Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TubeGeek on March 13, 2015, 11:09:52 pm

Title: Orange inspired project
Post by: TubeGeek on March 13, 2015, 11:09:52 pm
I am going to build myself an amp based on the Orange/Matamp tone. 

Any experts out there that have been down this road before and could offer me some insight?


I want thick distortion with sustain.  This link explains what I am going for:  Sleep - Dopesmoker (http://www.youtube.com/watch?v=hIw7oeZKpZc#ws)


I have ordered Heyboer Hiwatt 50W OT and PT for this project.  I also have a hiwatt size chassis and maple cabinet built that will work perfect.


Any info on this would be greatly appreciated.  I am in the beginning stages of collecting info and putting a plan together (layout).


Right now I am thinking of building from the orange overdrive series, which adds a master volume to the early 70's design. See schematic.


TG
Title: Re: Orange/Matamp style project
Post by: Glennjeff on March 14, 2015, 12:26:55 am
Wow,
Listening to that music got me stoned.  :l2:
Hope you chronic(le) the build.
Title: Re: Orange/Matamp style project
Post by: jojokeo on March 14, 2015, 04:15:08 am
I am going to build myself an amp based on the Orange/Matamp tone. 

Any info on this would be greatly appreciated.
I'm almost positive that sound/tone is not strictly from a tube amp w/out help from a pedal? I've got a pedal that does that easily. You try to do that by building a "specialized" tube amp and a one trick pony you will get and still very likely not reach that place you desire? Just my 2cents trying to save you money, time, & the trouble...
Title: Re: Orange/Matamp style project
Post by: VMS on March 14, 2015, 05:33:03 am
I think Sleep used Green amps, which might be based on matamp gt series amps.

www.youtube.com/watch?v=VlnWpzo2ZcM (http://www.youtube.com/watch?v=VlnWpzo2ZcM#ws)


Some links to Matamp schematics and info on green amps:

http://el34world.com/charts/Schematics/files/_Miscellaneous/Matamp_1973GT-120.jpg (http://el34world.com/charts/Schematics/files/_Miscellaneous/Matamp_1973GT-120.jpg)

http://el34world.com/charts/Schematics/files/_Miscellaneous/Matamp1973GT-120Schematic.gif (http://el34world.com/charts/Schematics/files/_Miscellaneous/Matamp1973GT-120Schematic.gif)

http://www.nicosonic.com/1st_tech_article (http://www.nicosonic.com/1st_tech_article)

http://www.planetoftheamps.com/amp-reviews.html (http://www.planetoftheamps.com/amp-reviews.html)
Title: Re: Orange/Matamp style project
Post by: TubeGeek on March 14, 2015, 10:40:21 am
I am going to build myself an amp based on the Orange/Matamp tone. 

Any info on this would be greatly appreciated.
I'm almost positive that sound/tone is not strictly from a tube amp w/out help from a pedal? I've got a pedal that does that easily. You try to do that by building a "specialized" tube amp and a one trick pony you will get and still very likely not reach that place you desire? Just my 2cents trying to save you money, time, & the trouble...


Yeah I hear what you're saying but I believe most of the tone is set by the amplifier and a pedal is used to add sustain and boost.  I already have 90% of the parts in my shop to build the amp so it's not a huge expense up front.  The only real expense was the transformers. 


This video demonstrates the vintage orange tone quite well.


https://www.youtube.com/watch?v=EcFCbzgBuMs (https://www.youtube.com/watch?v=EcFCbzgBuMs)
Title: Re: Orange/Matamp style project
Post by: TubeGeek on March 14, 2015, 10:42:43 am
I think Sleep used Green amps, which might be based on matamp gt series amps.

www.youtube.com/watch?v=VlnWpzo2ZcM (http://www.youtube.com/watch?v=VlnWpzo2ZcM#ws)


Some links to Matamp schematics and info on green amps:

http://el34world.com/charts/Schematics/files/_Miscellaneous/Matamp_1973GT-120.jpg (http://el34world.com/charts/Schematics/files/_Miscellaneous/Matamp_1973GT-120.jpg)

http://el34world.com/charts/Schematics/files/_Miscellaneous/Matamp1973GT-120Schematic.gif (http://el34world.com/charts/Schematics/files/_Miscellaneous/Matamp1973GT-120Schematic.gif)

http://www.nicosonic.com/1st_tech_article (http://www.nicosonic.com/1st_tech_article)

http://www.planetoftheamps.com/amp-reviews.html (http://www.planetoftheamps.com/amp-reviews.html)


Wow that is the clearest matamp gt120 schematic I have seen, thanks for the heads up!
Title: Re: Orange/Matamp style project
Post by: TubeGeek on March 14, 2015, 10:56:42 am
Several years ago I had a Matamp series 2000 come across my bench.  I immediately fell in love with it.  Something about the quality of construction and different way of doing things appealed to me.


The Series 2000 is not the high gain monster though, it is more of a bluesy type tone most well known to be used by Peter Green's Fleetwood Mac - Albatross.


What intrigues me is the circuitry design.  The FAC control, where it is inserted. The Matamp's have a cool design too. Matamp and Orange are pretty much the same thing to me.


I am thinking the way the cap switches are in these circuits play a big role in their tone(of course).  I have not analyzed it yet, not sure if I am that smart. :l2:  I am hoping some of the smarter dudes here can explain the circuit so it makes sense.  I attached a matamp schematic to reference what I am talking about.
Title: Re: Orange/Matamp style project
Post by: TubeGeek on March 14, 2015, 10:59:17 am
Another video that nails the tone I am seeking:


https://www.youtube.com/watch?v=KKb42Otbz5k (https://www.youtube.com/watch?v=KKb42Otbz5k)
Title: Re: Orange/Matamp style project
Post by: VMS on March 14, 2015, 11:33:47 am
If I'm not mistaken, this is the thread for that amp:

http://music-electronics-forum.com/t26551-3/#post320711 (http://music-electronics-forum.com/t26551-3/#post320711)


Title: Re: Orange/Matamp style project
Post by: HommeMarrBuckley on March 14, 2015, 11:35:46 am
Not an expert at all but definitely interested in this one TG.   A while back I was checking out the Matamp Gt 100.  According to many this schematic was pretty accurate.  Not sure with which amp you're headed.
http://vintageamps.com/plexiboard/viewtopic.php?f=4&t=99260 (http://vintageamps.com/plexiboard/viewtopic.php?f=4&t=99260)
I emailed a guy named John Mcneece who seems to know this circuit quite well.  Really interesting and nice guy---was browsing his site and came across Fender 400PS (nuts)
In regards to the GT he said
"The original GT was almost the same as the orange graphic, the OR has no second click switch, the EQ and FAC swap positions, plus a few slight component changes.
The Mats and oranges ran at 515-540 VDC on the plates. This affects headroom. Also it is rough on tubes. Marshall types usually end up at about 480VDC,
Their output transformers have a winding ratio that is different, extended frequency response, very hi-fi. The downside of this frequency response is a scary plate impedance that is very unkind to tubes. A modern EL34 will not last long unless the amp is played at jazz volumes. There are fixes for this but the amp will not sound have the 100% "Mat sound" so back to square one. "

I checked out Electric Transformers but were pricey and with this felt out of my realm--think I had trouble finding one of the rotary switches as well.  Planet of the amps site is pretty cool too.  I have seen your other builds so probably much easier for you to do.  Anxious to see what you produce.  When I want to go through walls, I dig some Pike, too.  High school and twenties--just fell in love with drop C and exotic tuning sound.  It came from the desert....Ahhh memories.



Title: Re: Orange/Matamp style project
Post by: HommeMarrBuckley on March 14, 2015, 11:49:33 am
Almost forgot and maybe off topic, but Steve's Sceptre or T-100 can probably achieve that sound as well.
Title: Re: Orange/Matamp style project
Post by: jojokeo on March 14, 2015, 02:45:03 pm
sorry I might have forgot to take into account the low tuning guitars contributing to that sound also. I was just looking at the schem briefly and going by experience.
Title: Re: Orange/Matamp style project
Post by: shooter on March 15, 2015, 08:42:37 am
Quote
The Mats and oranges ran at 515-540 VDC on the plates. This affects headroom. Also it is rough on tubes. Marshall types usually end up at about 480VDC

Is this how they're claiming "50W version" on the schematic.  I have a similar build done as a working prototype, my plate is at 430 and cathode R is 270 and I'm idling right at 25W/tube, but at the speaker the amps pwr is 24ish watts, which I would expect.  I'm having a hard time seeing 50W at the speaker without my tubes melting.  Can someone clear up my mud brain?

thanks
Title: Re: Orange/Matamp style project
Post by: VMS on March 15, 2015, 09:07:38 am
Mullard datasheet page 3 says Pout should be near 40 watts given that the Raa is the same:

http://frank.pocnet.net/sheets/129/e/EL34.pdf (http://frank.pocnet.net/sheets/129/e/EL34.pdf)

Title: Re: Orange/Matamp style project
Post by: shooter on March 15, 2015, 10:18:10 am
That's the datasheet I'm working from, but initially I was closer to the 3.5k Ra-a (B+370ish) but I changed taps and since B+ is closer to the 450 datasheet, I didn't use a 16ohm speaker to change my reflected impedance closer to 6.5k!!  Gotta do some measuring anyway so I'll do it with a 16ohm speaker n see if that gets me closer

thanks!
Title: Re: Orange/Matamp style project
Post by: Colas LeGrippa on March 15, 2015, 10:54:48 am
on the orange schems , C20 shows the same value as C19 which is 4700pF, I think it should be 10,000pF .


Colas
Title: Re: Orange/Matamp style project
Post by: TubeGeek on March 15, 2015, 02:36:03 pm
Looking over these designs I see something new to me:


The PT secondary HV centre tap connects to the middle +/- of the first filter cap node.  I am thinking this raises the B+ voltage higher than with just the 360-0-360 Pt specs?


This could be where the higher than typical B+ comes from, correct?
Title: Re: Orange/Matamp style project
Post by: shooter on March 15, 2015, 03:00:48 pm
Ya, I am Cathode biased, I was referencing the Matamp schematic that said 50W model, and that is cathode biased also.  That's what got me wondering how it's 50W - at the speaker, not as a room heater.

Title: Re: Orange/Matamp style project
Post by: TubeGeek on March 15, 2015, 03:02:56 pm
Another new thing to me is the depth, FAC controls. I am trying to wrap my brain around the mat amp design, it confusing to me.  I have a "mud brain" as shooter puts it!


They seem to me to be a way of filtering the signal.


The placement of these controls differs between them too.
Early matamp's have a more complex network that is inserted right at the input before v1a grid input and off the plate of v1a is another "fac" control.  The switching here is confusing as hell to me. :cussing:


Orange only has the fac control which is inserted off the plate of v1b.


My questions are how much does this affect the tone and I wonder what I am going to prefer?  I guess I will have to decide to build it and try them out and then I'll know what my ears like.  I'll probably begin with building the orange graphic mkII with a master volume as my foundation and experiment from there.
Title: Re: Orange/Matamp style project
Post by: TubeGeek on March 15, 2015, 03:04:06 pm
Ya, I am Cathode biased, I was referencing the Matamp schematic that said 50W model, and that is cathode biased also.  That's what got me wondering how it's 50W - at the speaker, not as a room heater.


Oh my bad.  You were referencing the series 2000.  I've got three of four schematics in front of me at the moment, it's getting a little confusing  :icon_biggrin:


I had that amp on bench, I'd say it's more of a 20W model for sure.
Title: Re: Orange/Matamp style project
Post by: VMS on March 15, 2015, 05:42:50 pm
To add to your confusement, these are probably somewhat proven builds:

for matamp I would go with schematic on this post:

http://music-electronics-forum.com/t38447-2/#post372170 (http://music-electronics-forum.com/t38447-2/#post372170)

and for orange with schematic on this weber kit:

https://taweber.powweb.com/store/kits_60b.htm#6o100 (https://taweber.powweb.com/store/kits_60b.htm#6o100)
Title: Re: Orange/Matamp style project
Post by: shooter on March 15, 2015, 06:30:54 pm
Quote
how much does this affect the tone and I wonder what I am going to prefer?

I think that's the point of the circuit, to give "lots?" of tonal choices.  I knew I seen that circuit, here's the link
http://home.comcast.net/~seluckey/amps/dual_lite/Dual%20Lite.pdf (http://home.comcast.net/~seluckey/amps/dual_lite/Dual%20Lite.pdf)

Good luck n thanks for clearing up the 20/40watt thing, so the amp schematic should read "50W heater, 20W amp" :icon_biggrin:
Title: Re: Orange/Matamp style project
Post by: darryl on March 15, 2015, 09:02:05 pm
The PT secondary HV centre tap connects to the middle +/- of the first filter cap node.  I am thinking this raises the B+ voltage higher than with just the 360-0-360 Pt specs?

(http://i497.photobucket.com/albums/rr333/valvetone/2015%20Projects/orange%20PT%20.jpg_zpshpkzluty.png) (http://s497.photobucket.com/user/valvetone/media/2015%20Projects/orange%20PT%20.jpg_zpshpkzluty.png.html)

The DC voltage at the transformer centre tap is exactly 50% of B+, so this circuit is a simple way to provide a reference for the junction of the series filter caps. In amplifier designs where the screen voltage is required to be 50% of the plate voltage, this centre tap arrangement is a very effective way of generating the screen supply.

The diode bridge in the above drawing is incorrect - the bridge needs to be rotated 90 degrees counter clockwise.
Title: Re: Orange/Matamp style project
Post by: TubeGeek on March 15, 2015, 09:25:44 pm
The PT secondary HV centre tap connects to the middle +/- of the first filter cap node.  I am thinking this raises the B+ voltage higher than with just the 360-0-360 Pt specs?

(http://i497.photobucket.com/albums/rr333/valvetone/2015%20Projects/orange%20PT%20.jpg_zpshpkzluty.png) (http://s497.photobucket.com/user/valvetone/media/2015%20Projects/orange%20PT%20.jpg_zpshpkzluty.png.html)

The DC voltage at the transformer centre tap is exactly 50% of B+, so this circuit is a simple way to provide a reference for the junction of the series filter caps. In amplifier designs where the screen voltage is required to be 50% of the plate voltage, this centre tap arrangement is a very effective way of generating the screen supply.

The diode bridge in the above drawing is incorrect - the bridge needs to be rotated 90 degrees counter clockwise.


Makes sense with the CT. Learned something new.  Seems obvious now.


Yes i saw the rectifier was incorrect.  This was pointed out in another forum as well, which may be where i found it.


I have been staring at these schematics this weekend in an effort to clear up any mud.  Im looking closer at Weber's design now.  Looks like they did all the work for me. Between all the info i have, i have got plenty to work from.  Ill post more as i get to it.
Title: Re: Orange/Matamp style project
Post by: Glennjeff on March 15, 2015, 09:32:27 pm
This circuit is different enough from "the usual" stuff to be interesting.
The tone is great for "that" style of metal.
I for one will watch with interest.

Is it the triple ganged switch across stage 1 and 2 that is doing your head in. Switches will do that

That switch appears to be providing a range of treble and bass contours to the preamp.

In the first two positions it is applying negative feedback that has bass emphasis, thereby cutting bass / low mid response.
The second position also puts a bright capacitor onto the gain pot.

In the third position the switch does nothing new.

In the fourth position it is putting a bright capacitor across the gain pot.


All the best
Glenn

Title: Re: Orange/Matamp style project
Post by: TubeGeek on March 15, 2015, 09:37:55 pm
This circuit is different enough from "the usual" stuff to be interesting.
The tone is great for "that" style of metal.
I for one will watch with interest.

Is it the triple ganged switch across stage 1 and 2 that is doing your head in. Switches will do that

That switch appears to be providing a range of treble and bass contours to the preamp.

In the first two positions it is applying negative feedback that has bass emphasis, thereby cutting bass / low mid response.
The second position also puts a bright capacitor onto the gain pot.

In the third position the switch does nothing new.

In the fourth position it is putting a bright capacitor across the gain pot.


All the best
Glenn


Switches have always caused me grief. 


This tone may not be everyone's cup o tea, but thats doesn't matter to me.  I like the tone enough to build one so when i feel like playing loud with lots of thick distortion, I can do it anytime i want :m11 I enjoy playing this kind of riffage while I record it on my looper and then sit behind the drums and bang away for a while.  It is a great stress reliever after a long day at work,  i have my looper setup with multpile outputs so i can also have a bass loop playing to its own output, into a bass amp.  Its a one man band setup and only i hear how bad i play  :l2:


Title: Re: Orange/Matamp style project
Post by: Glennjeff on March 15, 2015, 10:03:12 pm
The tone actually grows on you the more you listen to it.

Sounds like you've got a great "fun with my instruments" setup.
Drums are the best for de-stressing applications.  :icon_biggrin:
Title: Re: Orange/Matamp style project
Post by: MFowler on March 18, 2015, 12:14:54 am
I built this Orange amp quite a few years ago.
Title: Re: Orange/Matamp style project
Post by: lego4040 on March 18, 2015, 03:10:27 pm
Damn that green Matamp in reply 8 is the shit. Have you ever listened to the band "The Storm"? If not, Its like vintage Sabbath on Roids. Another amp to go on the Bucket build list
Title: Re: Orange/Matamp style project
Post by: TubeGeek on March 18, 2015, 10:37:37 pm
I ordered a pair of Celestion G12H-75 Creamback speakers for this project.


That means I will have three sets to choose from when it is done…Vintage 30's, Vintage Fane's and the Creambacks. 


I am going with a 2x12" cabinet, covered in orange tolex with white small cane grill cloth.


I have a fairly clear direction on the circuit now.  I've been studying and pondering it for a week or two now.  It's going to be based on the Orange OR80/120, Weber 6O100 and experiments with ideas from the Matamp/Electric schematic.  Hopefully I'll find what I am looking for between them after some noodling.


Title: Re: Orange/Matamp style project
Post by: MFowler on March 19, 2015, 01:31:36 am
I built this Orange amp quite a few years ago.


Thanks for sharing.


Looks like a nice circuit, does it nail this kind of tone?


Very versatile amp due to the ability to switch from Class A cathode bias 30w or Class AB fixed bias 50w.  I guess a person would need to find a good quality audio of this amp to compare with other Orange offerings.  Mine has plenty of gain and is loud.
Title: Re: Orange/Matamp style project
Post by: jojokeo on March 28, 2015, 11:08:40 am
Nice work Fowler, but what's the reasoning with all the pots being dual ganged like that (safety/redundancy?)? On some it would put them in parallel so they would be 1/2 the value of what the schem possibly? (I can't see the schem as it's too small).
Title: Re: Orange/Matamp style project
Post by: lego4040 on May 26, 2015, 03:26:33 pm
 :dontknow:  How did this amp turn out? Its been a few months. Also If I was intersested in building that Series 2000 for that Peter Green clean sound which schematic/layout would be the best to follow?
Title: Re: Orange/Matamp style project
Post by: TubeGeek on May 28, 2015, 10:35:36 am
:dontknow:  How did this amp turn out? Its been a few months. Also If I was intersested in building that Series 2000 for that Peter Green clean sound which schematic/layout would be the best to follow?


I have everything I need to build the amp but no time to do it. Now that the weather is getting nicer where I live, I will be spending my free time in the mountains camping.


The amp will get built just not sure when I will be inspired.  I'll update when I do get to it.
Title: Re: Orange/Matamp style project
Post by: TubeGeek on September 02, 2015, 06:48:17 pm
Summer is ending so I am getting back to working on projects.  :headbang:


I have clear coated the maple head cabinet and have worked out the details on the front faceplate and control plate.


Next step will be to mark the chassis layout and drill.


This weekend I am planning to tolex the 2x12 cabinet and speaker baffle.


Following that I will be working out the final details on the circuit I am building.  I have 3 or 4 schematics to look at.


Thought I would update on this project as I go...
Title: Re: Orange/Matamp style project
Post by: TubeGeek on September 02, 2015, 07:12:37 pm
I also painted the transformers
Title: Re: Orange/Matamp style project
Post by: lego4040 on September 03, 2015, 12:18:35 am
Oh that is nice sweet Cab. That's gonna be a heavy cabinet to lug around too, where did you score nice maple like that? Great grain and lining up at the dove tails.
Title: Re: Orange/Matamp style project
Post by: HommeMarrBuckley on September 03, 2015, 08:05:59 am
What transformers did you go with?
Are you using one schematic and veering off here and there?
Where you source the chassis and size?
Sorry for being nosey, just curious.
Looking pretty rad.  Nice :bravo1:
Title: Re: Orange/Matamp style project
Post by: TubeGeek on September 03, 2015, 09:32:01 am
Oh that is nice sweet Cab. That's gonna be a heavy cabinet to lug around too, where did you score nice maple like that? Great grain and lining up at the dove tails.


Thanks!  I found the spalted maple wood at my local lumber store.  My buddy did the wood work for me. 


I don't plan on taking the cabinet around much, it'll pretty much stay in my studio/shop.
Title: Re: Orange/Matamp style project
Post by: TubeGeek on September 03, 2015, 09:41:55 am
What transformers did you go with?
Are you using one schematic and veering off here and there?
Where you source the chassis and size?
Sorry for being nosey, just curious.
Looking pretty rad.  Nice :bravo1:


I chose to go with Heyboer's 50W Hiwatt PT and OT and a Hammond choke (reactor as Hammond says on it)


I am trying to iron out the circuit details but at the moment I am pretty much going with the Weber 6O100 circuit.  It is close to what the original circuit is, with an added mid control and a presence control.  I will be experimenting with different values and may not add the mid and presence controls.  That's why I had two faceplates made up, so I can experiment and see what I prefer.  I may also experiment with placement of the fac drive controls(matamp style). My goal is to build the original orange circuit with a master volume, this would be the overdrive series.  Weber has done most the work for me, I just need to build it and tweak to my liking.


The chassis size was sourced from a Hiwatt Custom 50 I built years ago.  At the time I built the hiwatt, I had 3 of these chassis made up.  I used one for the hiwatt, one for an ac30 and now this last one for the orange.
Title: Re: Orange/Matamp style project
Post by: lego4040 on September 03, 2015, 10:24:45 am
That faceplate is incredible, would you mind telling us your source? I need a faceplate for my 5G9 build. My Combo cab came in last week but I had to send back, mix up in their shipping department.
Title: Re: Orange/Matamp style project
Post by: TubeGeek on September 03, 2015, 12:18:17 pm
That faceplate is incredible, would you mind telling us your source? I need a faceplate for my 5G9 build. My Combo cab came in last week but I had to send back, mix up in their shipping department.


I take my ideas to a local laser engraver where we sit down and design the layout in corel draw and then laser etch the lamacoid product with the color I choose.


On a DIY project like this one I like to have the faceplate made up before I drill the chassis holes.  It makes it a little easier to get the holes lined up properly.


http://www.miragelaserdesigns.com/index.html (http://www.miragelaserdesigns.com/index.html)


We are in Alberta Canada, not sure if that'll work for you but he does ship his stuff all around the world.
Title: Re: Orange/Matamp style project
Post by: Fresh_Start on September 03, 2015, 12:36:13 pm
The DC coupled cathodyne phase inverters of the old Matamp and Orange amps have me confused. The Weber schematic above shows a "normal" AC coupled cathodyne with a grid return resistor connected to the bottom of a small cathode basing resistor. However, the old Matamp and Orange schematics simply show 100K cathode and anode resistors on the PI with the grid connected directly to the preceding stage's plate. No grid stopper and I don't understand how the PI triode is biased.

Help?

Chip

P.S.  Forgive me if this seems off topic.
Title: Re: Orange/Matamp style project
Post by: TubeGeek on September 03, 2015, 03:03:49 pm
The DC coupled cathodyne phase inverters of the old Matamp an Orange amps have me confused. The Weber schematic above shows a "normal" AC coupled cathodyne with a grid return resistor connected to the bottom of a small cathode basing resistor. However, the old Matamp and Orange schematics simply show 100K cathode and anode resistors on the PI with the grid connected directly to the preceding stage's plate. No grid stopper and I don't understand how the PI triode is biased.

Help?

Chip

P.S.  Forgive me if this seems off topic.


I am glad you asked! I have the same question.
Title: Re: Orange Project
Post by: Fresh_Start on September 03, 2015, 09:32:38 pm
Merlin has a nice explanation of cathodyne phase inverters, but it doesn't cover this variant at all.
http://www.valvewizard.co.uk/cathodyne.html (http://www.valvewizard.co.uk/cathodyne.html)

I don't remember seeing this approach before.

Cheers,
Chip
Title: Re: Orange Project
Post by: sluckey on September 03, 2015, 09:48:38 pm
Quote
Merlin has a nice explanation of cathodyne phase inverters, but it doesn't cover this variant at all.
Look at his page on the dc cathode follower. It's the same thing. Well, it is if you split the cathode resistor, putting half on the plate, half on the cathode.

     http://www.valvewizard.co.uk/dccf.html (http://www.valvewizard.co.uk/dccf.html)

That dc cathodyne has been around a long time. A couple years ago I converted a 1954 Rockola jukebox amp to guitar that had that PI. I kept the PI and PA and just put an AB763 preamp in front.

     http://home.comcast.net/~seluckey/amps/rocky/rocky.pdf (http://home.comcast.net/~seluckey/amps/rocky/rocky.pdf)

EDIT... The Magnatone 260 and 280A guitar amps both use that same PI. The 260 schematic is too big to post but here's the 280A...

     http://magnatoneamps.com/schematics/magnatone_280a.pdf (http://magnatoneamps.com/schematics/magnatone_280a.pdf)
Title: Re: Orange Project
Post by: TubeGeek on November 07, 2015, 04:47:18 pm
The long overdue project continues….


This project gets put on the shelf when I have requests to build for others.  It's been a while now but I finally have a weekend free of other's amp work so onto this project for a few days.


My goal this weekend is to get the metal chassis drilled and primed and possibly the first coat of paint completed.  My idea is to paint the outside and inside of the chassis with a hemi orange enamel spray paint.


I have been working on the chassis layout and this is what i have come up with.  I need to ask some opinions on the orientation of the output transformer.  Which way would you face the OT laminations? vertical or horizontal? Or would it even make a difference?


My thinking is to mount the OT with the laminations going horizontally because I think there may be less "magnetic flux" or force-fields going directly into the preamp tube area (top right of the pic), if it were to be mounted with the laminations going vertical.  Horizontal concerns me because they are in the same direction of the PT. Or are they far enough apart  that it won't matter?
 :w2:
Title: Re: Orange Project
Post by: TubeGeek on November 07, 2015, 04:56:06 pm
Here is the chassis inside layout so far
Title: Re: Orange Project
Post by: sluckey on November 07, 2015, 05:35:04 pm
Your layout resembles a Sunn. Maybe this will give you some ideas. I can post a gut shot too if this looks interesting...
Title: Re: Orange Project
Post by: TubeGeek on November 07, 2015, 06:09:08 pm
Judging by the sunn I doubt I will have to be concerned with the OT placement. Thx.
Title: Re: Orange Project
Post by: jojokeo on November 07, 2015, 09:30:53 pm
Turn your power tranny so the laminations are not pointing at your power tubes (turn it  90°). Laying down the OT does help with coupling but being on the other side of the chassis (which I always advocate) you should be fine either way. Solder or clip up a "listening device" to be sure. Separately wire nut or tape up your secondary windings of PT and apply power in it's position. Then attach headphones or ear plugs to the OT secondary. Listen to noise from PT as you move around the OT in various positions.
Title: Re: Orange Project
Post by: TubeGeek on December 06, 2015, 12:16:41 am
Made a little progress in between other projects...
Title: Re: Orange Project
Post by: TubeGeek on December 06, 2015, 12:19:12 am
One more...
Title: Re: Orange Project
Post by: Willabe on December 06, 2015, 12:31:21 am
Wow! That'll get someones attention!  :icon_biggrin:
Title: Re: Orange Project
Post by: jojokeo on December 06, 2015, 10:37:06 am
Looks great tubegeek but photos are a bit too small to even read what the controls are and any other details. Did you try "listening" to the trannies regarding placements? Results?
Title: Re: Orange Project
Post by: TubeGeek on December 06, 2015, 03:05:20 pm
Looks great tubegeek but photos are a bit too small to even read what the controls are and any other details. Did you try "listening" to the trannies regarding placements? Results?


The faceplate is not final yet.  I didn't realize when I had the plate made that the text was a little too close to the pots.  I plan to make another faceplate where the text is raised and maybe a little larger and will also decide on the control names at that point.  I want to rename "drive" to "FAC".  I may not have a mid or presence control either.  These details will be worked out after I get it working and experiment.  This plate helped me mark the chassis for drilling.  Orange isn't a popular colour of material so I had to purchase a 2x2' sheet of material, thus I am willing to go through a few versions before settling on a final design.


As for the transformer placement…I will cross that bridge if I have an issue with hum when powered up.


I was just excited to share pics of the painting.
Title: Re: Orange Project
Post by: jojokeo on December 06, 2015, 06:04:40 pm
Gotcha, I do the same many times where a control becomes different. Nice to have a faceplate "template" too.
Title: Re: Orange Project
Post by: nateflanigan on December 07, 2015, 08:28:35 pm

Cool project!

I have an Orange OD 120, it's an awesome amp, WAY more versatile than most people give them credit for.  I've always thought these would make a great DIY project.  The master volume on the stock schematic sounds really bad, you can take a little off but anymore and the tone goes out the window.  I converted it to a Lar/Mar which works great.

Title: Re: Orange Project
Post by: TubeGeek on December 09, 2015, 12:03:06 am

Cool project!

I have an Orange OD 120, it's an awesome amp, WAY more versatile than most people give them credit for.  I've always thought these would make a great DIY project.  The master volume on the stock schematic sounds really bad, you can take a little off but anymore and the tone goes out the window.  I converted it to a Lar/Mar which works great.






Awesome, thanks for commenting and sharing your experience with master volumes.  I may have a question or two for you before I am done if that's ok!?
Title: Re: Orange Project
Post by: navdave on December 09, 2015, 03:02:18 am
I've built two of these one a clone of an Orange GRO the other my own take on the same  Circuit tweeked to my liking both non master volume amps. These are not bedroom level amps and if you want distortion ....!!!  If you use a fuzz or distortion pedal you're in business
 Here is the link to the one I built the GRO clone with and without pedals.
http://youtu.be/0vI_HRBwK9w (http://youtu.be/0vI_HRBwK9w)
Title: Re: Orange Project
Post by: nateflanigan on December 09, 2015, 06:54:38 pm
TubeGeek, of course, happy to help in anyway I can. 


With the Lar/mar I can play at "reasonable" levels and still have the input gain set really high.  I don't know that I'd call it bedroom levels, but, I don't know, I'm still married  :w2:
Title: Re: Orange Project
Post by: TubeGeek on December 13, 2015, 10:45:54 pm
I've built two of these one a clone of an Orange GRO the other my own take on the same  Circuit tweeked to my liking both non master volume amps. These are not bedroom level amps and if you want distortion ....!!!  If you use a fuzz or distortion pedal you're in business
 Here is the link to the one I built the GRO clone with and without pedals.
http://youtu.be/0vI_HRBwK9w (http://youtu.be/0vI_HRBwK9w)


Cool, thanks for sharing that.  That's exactly what I am going for.  I was expecting to get that super thick distortion from the amp itself but that may not be realistic.  I don't play these kind of amps at bedroom volume levels often, I like to push some air out of the speakers.
Title: Re: Orange Project
Post by: TubeGeek on December 13, 2015, 10:48:35 pm
TubeGeek, of course, happy to help in anyway I can. 


With the Lar/mar I can play at "reasonable" levels and still have the input gain set really high.  I don't know that I'd call it bedroom levels, but, I don't know, I'm still married  :w2:


 :l2:  I will try a few different master volume circuits and find the right one. I can hardly wait to clear up my projects on the go to dedicate time to finishing this. It's looking like that could be in March next year. ugh.
Title: Re: Orange Project
Post by: nateflanigan on December 14, 2015, 06:15:47 am
You'll love it, really cool amp.  Sounds great on bass too.
Title: Re: Orange Project
Post by: TubeGeek on February 05, 2016, 11:34:21 pm
I am at the point of building the circuitry now....Here is a pic of my progress.


I have a few questions about the FAC control.  I see three options for where to place it.  The input, after first gain stage and after the tonestack, before the phase inverter.


What do you guys prefer? Any opinions or experience with this?


My gut instinct says at the input is where I will like it. I will experiment and see what I actually like but I was hoping for some input as to where I should begin with.


Also capacitor values seem to be different between the schematics and layouts I am referencing.  Any opinions on what cap values make the most sense?
Title: Re: Orange Project
Post by: TIMBO on February 06, 2016, 03:26:48 am
Man, That is some awesome amp. :icon_biggrin:
Title: Re: Orange Project
Post by: nateflanigan on February 06, 2016, 08:39:10 am
Looking good!


Here's the schematic for my amp. 
http://www.orangefieldguide.com/OFG_SCHEM/ODschem_A.gif (http://www.orangefieldguide.com/OFG_SCHEM/ODschem_A.gif)
It's the only Orange I've ever played, so I can't really comment on the location of the FAC control, other than that it sounds great and is very useful before the PI.  However as far as cap values go I pretty much only use the first three positions on the switch, it gets pretty thin sounding beyond that.
Title: Re: Orange Project
Post by: TubeGeek on February 06, 2016, 02:33:15 pm
I've built two of these one a clone of an Orange GRO the other my own take on the same  Circuit tweeked to my liking both non master volume amps. These are not bedroom level amps and if you want distortion ....!!!  If you use a fuzz or distortion pedal you're in business
 Here is the link to the one I built the GRO clone with and without pedals.
http://youtu.be/0vI_HRBwK9w (http://youtu.be/0vI_HRBwK9w)


Is the freq control on this right after the input?
Title: Re: Orange Project
Post by: TubeGeek on February 06, 2016, 02:39:55 pm
Looking good!


Here's the schematic for my amp. 
http://www.orangefieldguide.com/OFG_SCHEM/ODschem_A.gif (http://www.orangefieldguide.com/OFG_SCHEM/ODschem_A.gif)
It's the only Orange I've ever played, so I can't really comment on the location of the FAC control, other than that it sounds great and is very useful before the PI.  However as far as cap values go I pretty much only use the first three positions on the switch, it gets pretty thin sounding beyond that.


Thanks.


So in switch position one (33pF) you have the most low end and then as you switch up to the 4700pF, you have less low end frequencies?



Title: Re: Orange Project
Post by: sluckey on February 06, 2016, 02:56:09 pm
Quote
So in switch position one (33pF) you have the most low end and then as you switch up to the 4700pF, you have less low end frequencies?
It's just the opposite. In position 1 the signal must travel through that entire string of series caps. The total capacitance is equal to the reciprocal of the sum of reciprocals, IOW, the total capacitance value will be less than the value of the smallest cap in that chain, ie, less than 33pF. That's a tiny coupling cap and will only pass high freq. (That 33pf seems like a ridiculously small value. I wonder if it should be 330pF?) As the switch is mover to lower positions the total capacitance increases and allows more low freqs to pass.
Title: Re: Orange Project
Post by: TubeGeek on February 06, 2016, 05:46:42 pm
Quote
So in switch position one (33pF) you have the most low end and then as you switch up to the 4700pF, you have less low end frequencies?
It's just the opposite. In position 1 the signal must travel through that entire string of series caps. The total capacitance is equal to the reciprocal of the sum of reciprocals, IOW, the total capacitance value will be less than the value of the smallest cap in that chain, ie, less than 33pF. That's a tiny coupling cap and will only pass high freq. (That 33pf seems like a ridiculously small value. I wonder if it should be 330pF?) As the switch is mover to lower positions the total capacitance increases and allows more low freqs to pass.


I think you're right about the 33pF cap, it is 360pF on the schematics I am referencing.  Weber is using all 0.0047uF caps on the switch whereas the matamp and orange schematics are each using their own dissimilar values.  I'll need to experiment with what I think sounds best.


Steve, do you have an opinion on where you'd insert this cap switch either at the input or before the PI?


I just need to build the damn thing and experiment  :l2:
Title: Re: Orange Project
Post by: sluckey on February 06, 2016, 06:38:11 pm
I think I'd leave the switch right where it is. I like the idea of using all .0047s on the switch. Makes the math easy and I think it would still give an effective tone change.
Title: Re: Orange Project
Post by: TubeGeek on February 13, 2016, 12:31:41 pm
Just wired up the frequency analysis control (FAC), Drive, Contour....using all 0.0047uF orange drop caps


In switch position:


1: 1.2nF
2: 1.4nF
3: 1.8nF
4: 2.4nF
5: 4.4nF
6: Won't register on my DMM, i figure the math needs to be worked out to know this exact value or my best guess would be around 10nF


Assuming I have wired this control correctly, could have it backwards, won't know until I listen to it in use.
Title: Re: Orange Project...its alive!
Post by: TubeGeek on February 15, 2016, 02:24:13 am
The amp was born at 10:38pm last night. :icon_biggrin:


Sounds really good to me and exactly what I was going for. 


Now comes the fun part...getting to know the tone and tweaking until I am really happy.


I still have to tolex the 2x12 cabinet and apply the white cane grill cloth and have a final faceplate made.  Once all the details are finished, I will create a slideshow of the build along with audio of the amp recorded.  Stay tuned for that in the coming weeks.


I have been doing a happy dance since she was born! :headbang: :m11



Title: Re: Orange Project...it's alive!
Post by: Fresh_Start on February 15, 2016, 08:22:08 am
Yay!


Title: Re: Orange Project...it's alive!
Post by: lego4040 on February 16, 2016, 01:01:46 pm
 :worthy1: holy smokes. Maybe  using smaller boss style knobs would work
Title: Re: Orange Project...its alive!
Post by: HommeMarrBuckley on February 22, 2016, 10:06:11 pm
The amp was born at 10:38pm last night. :icon_biggrin:



NICE!


Can't wait to see/hear how it comes out.
Total tip top and love what you did so far.
Title: Re: Orange Project...it's alive!
Post by: TubeGeek on February 22, 2016, 11:37:53 pm
Update:


I had a new faceplate made with the text raised up above the chicken heads.  I also renamed a few things and added my logo to it above the pilot lights.


Working on finishing the cabinet.  Tolexing was finished yesterday.  I did the speaker baffle tonight.  I have the back panel to do and then it's complete.


I am surprised at the tone I can get out of this.  I figured I was building a one trick pony but I now know it'll do a couple nice tones.


Next will be a little video of the entire build process with the audio being this amp recorded....
Title: Re: Orange Project...it's alive!
Post by: Willabe on February 22, 2016, 11:40:33 pm
Man that thing is gorgeous!  :icon_biggrin:   

Next will be a little video of the entire build process with the audio being this amp recorded....

Oooooo, nice!    :icon_biggrin:
Title: Re: Orange Project...it's alive!
Post by: DummyLoad on February 23, 2016, 12:07:02 am
nice!   :icon_biggrin:


--pete
Title: Re: Orange Project...it's alive!
Post by: TubeGeek on March 06, 2016, 12:06:59 am
I have been playing the amp as much as possible, learning how to dial it in.


I find it requires a different approach to setting up the tone you want.  How the treble, high frequency drive and presence all work, the amp can be uniquely tuned.  What I am enjoying the most is the low end grind it has.  It is a fun amp to play if you enjoy that style of music.


I took it to the local music store for a demo and got some opinions and feedback from local musicians.  Here are links to a few short iPhone videos of the amp being played on my youtube channel:


https://youtu.be/wveEGviy-fQ (https://youtu.be/wveEGviy-fQ)


https://youtu.be/ohaBmMLxoGQ (https://youtu.be/ohaBmMLxoGQ)


A more thorough slideshow and recording is still a work in progress.
Title: Re: Orange inspired project
Post by: TIMBO on March 07, 2016, 03:13:27 am
Well done ,sounds awesome.
Title: Re: Orange inspired project
Post by: Glennjeff on May 07, 2016, 11:58:25 am
Everything about that amp project is fabulous.
Sound is quite unique and  I really like it, even if it make me want to self harm a little. :laugh:
Title: Re: Orange inspired project
Post by: TubeGeek on May 08, 2016, 11:23:42 pm
Thanks for the compliments.  One of these days I'll post a slideshow of the build...just been too busy to get around to creating it.
Title: Re: Orange inspired project
Post by: TubeGeek on May 26, 2016, 12:19:44 am
Final post.  I made a slideshow of this project:


https://youtu.be/K460r9ogeYE (https://youtu.be/K460r9ogeYE)
Title: Re: Orange inspired project (added slideshow)
Post by: SILVERGUN on May 26, 2016, 11:44:24 am
Great work!
Nice thread, documentation, and final product.
Keep up the good work and don't ever think we don't wanna see this stuff.

 :bravo1:
Title: Re: Orange inspired project (added slideshow)
Post by: TubeGeek on May 26, 2016, 01:40:20 pm
Great work!
Nice thread, documentation, and final product.
Keep up the good work and don't ever think we don't wanna see this stuff.

 :bravo1:


Thank you!
Title: Re: Orange inspired project (added slideshow)
Post by: HommeMarrBuckley on May 27, 2016, 11:17:02 pm
TG,
While watching your slideshow, you really conveyed the most important part: you thoroughly enjoyed your build!!  I must say I was smiling the whole time too.  Like others have done on this forum, as well, it epitomizes what planning and a thought out goal can become.  A super cool looking melody machine.  Well done and many thanks for documenting!  Very inspiring!
Title: Re: Orange inspired project (added slideshow)
Post by: Glennjeff on June 16, 2016, 12:09:34 am
Did you do the music with this amp, had as blast hammering out various modes of harmonic minor to it.
Title: Re: Orange inspired project (added slideshow)
Post by: TubeGeek on June 16, 2016, 09:31:47 am
Did you do the music with this amp, had as blast hammering out various modes of harmonic minor to it.


At the beginning of the slideshow I credit the music to a band called "Spaceslug".  The sound of my amp is similar to what you're hearing.  I haven't found the time to make a full band recording of the amp quite yet.


It is fun to jam too eh!?
Title: Re: Orange inspired project (added slideshow)
Post by: TubeGeek on June 16, 2016, 09:34:08 am
TG,
While watching your slideshow, you really conveyed the most important part: you thoroughly enjoyed your build!!  I must say I was smiling the whole time too.  Like others have done on this forum, as well, it epitomizes what planning and a thought out goal can become.  A super cool looking melody machine.  Well done and many thanks for documenting!  Very inspiring!


Thanks for the comment.  I sure did enjoy this project. 
Title: Re: Orange inspired project (added slideshow)
Post by: TubeGeek on November 30, 2016, 11:33:55 am
Update: 


I decided to change out the Celestion Creamback speakers for a Weber Black Shuck and Weber Gray Wolf.


The low end has opened up and the amp sounds even bigger and meaner :headbang: