lego's spin on Sluckey's AC15

[sluckey]

I am going shopping for something to use for buss wire.

I normally use 14AWG copper house wire but I'm out of that so I used 17 gauge steel electric fencing wire on this project. It's very stiff. I like it better than the copper. Use flux on every solder joint to ensure you cut through the galvanized coating. You can find it at Tractor Supply Co. Or go visit someone in the country. They'll gladly give you a lifetime supply. Here's a link...

http://www.tractorsupply.com/en/store/fi-shocktrade%3B-steel-wire-17-gauge-350-ft?cm_vc=-10005

[Willabe]

I am still looking for the meter jack tips that have metal threads and nuts. 

Mouser/Digikey used to have them, they probable still do. I think they called them heavy duty tip jacks(?), military spec, their metal clad.


               Brad     

[Ed_Chambley]

I am going shopping for something to use for buss wire.

I normally use 14AWG copper house wire but I'm out of that so I used 17 gauge steel electric fencing wire on this project. It's very stiff. I like it better than the copper. Use flux on every solder joint to ensure you cut through the galvanized coating. You can find it at Tractor Supply Co. Or go visit someone in the country. They'll gladly give you a lifetime supply. Here's a link...

http://www.tractorsupply.com/en/store/fi-shocktrade%3B-steel-wire-17-gauge-350-ft?cm_vc=-10005

Kewl, I have a tractor supply very close to me.  I will go by as I am sure I can find more to buy than this.


I normally use the copper as well, but this looks like it holds shape much better.


Ignore the question coming from another direction.  I sent it before I sent this.

[Ed_Chambley]

I am still looking for the meter jack tips that have metal threads and nuts. 

Mouser/Digikey used to have them, they probable still do. I think they called them heavy duty tip jacks(?), military spec, their metal clad.


               Brad     

Found them Mouser.  Red, Black and gray.  Thanks, I will get them on my last forgot that order.


I was looking at my 5 watt ceramic  22k block resistors and not sure if I am going to like how they fit.  Man, this board is tight.  I think I have spent more time planning on this board than any other.

[sluckey]

Hopefully I've made the last solder joint on this amp. (I know, wishful thinking)

If I do any more pics they will be on my website (eventually).

[SILVERGUN]

 

 

[Willabe]

Yeah! Looks top shelf!

And she sounds?

And how does the vibrato sound compared to your Warbler and Revibe?


           Brad     

[Ed_Chambley]

Great Work Sluckey!  Look for UPS tomorrow.  I just got through cross referencing the schematic to the layout noting resistor values.  Man, there is a lot of parts.  I am not sure, but I believe this is the most parts for a seemingly simple amp I have ever seen.


I have a long way to go, but I have a good guideline.  I hope I can get to this before it gets lost.  I believe it belongs in the archives when Lego gets his built.  I may not get done before I have to take a long break for some neck repair.


I hope it sounds great and you need no tweaking as it sounds like you are tired of working on it right now.


Thanks for this as I have wanted one for a long time.

[Ed_Chambley]

Hopefully I've made the last solder joint on this amp. (I know, wishful thinking)

If I do any more pics they will be on my website (eventually).

What is your tube lineup.  I would think you have some nice old stock.  Did your bias check out?

[lego4040]

  a picture is worth a thousand words. She is beautiful and I'm sure will ring like a bell. Is she going in a donor cabinet or a new one. My new tube book came in and I'm reading a article about adding a simple but worthy mod, the power attenuators. Even at 15 watts that amp is gonna be loud and being able to hit that sweet spot at lower volumes I couldn't see why not mentioning this

[sluckey]

I haven't powered the amp on yet, other than to check power supply and filaments several days ago. I need a break from this thing. I'll get back on it Saturday after I heal a bit!  I'm not even gonna look at it tomorrow. Well, maybe a quick peek.

[Willabe]

I'm not even gonna look at it tomorrow. Well, maybe a quick peek.

                   

[Ed_Chambley]

Does the footswitch just ground the grid turning off the tremolo?  I am using only the 2 high inputs as well and going to jump the channels with a rear mini toggle.  I have gotten some individual turrets and plan the same approach with the grid stoppers.  Could I simply wire to the turrets to jump the channels or would it be best to connect at the tube socket?

[tubenit]

Sluckey,

That is one of the best looking layouts and wiring jobs I've ever seen.  Phenomenally well done!  Incredibly impeccable work.

I can't wait to hear a review of how it sounds  .......... or better yet, a sound clip.  You're a great guitarist, so I know you could pull off something really nice to listen to.

Best regards and respect, Tubenit

[Ed_Chambley]

On the original schematic C25 is .033uf and is on the new Vibrato schematic which is C42, but a note stating .047uf in red appears as well.  Any reason for the variation or suggested different value?

[sluckey]

Does the footswitch just ground the grid turning off the tremolo?

No. The FS applies a ground to the 1M resistors in the phase shift loop which enables the oscillator.

Could I simply wire to the turrets to jump the channels or would it be best to connect at the tube socket?

I would wire to the turrets. That way each tube still has it's dedicated grid stopper. BTW, I used 33Ks between the turret and the socket.

On the original schematic C25 is .033uf and is on the new Vibrato schematic which is C42, but a note stating .047uf in red appears as well.  Any reason for the variation or suggested different value?

Yes. The schematic shows a .033. Another schematic I have says it's .005 and I didn't believe that. So, I checked on another forum to see if anyone knew the real value. One guy posted a closeup pic of his REAL 1960 AC15. The cap (and it's original) in his amp was really .047! .033 and .047 are close enough for me. I put a .033 on my board just to keep to the original schematic.

[Ed_Chambley]

Does the footswitch just ground the grid turning off the tremolo?

No. The FS applies a ground to the 1M resistors in the phase shift loop which enables the oscillator.

Could I simply wire to the turrets to jump the channels or would it be best to connect at the tube socket?

I would wire to the turrets. That way each tube still has it's dedicated grid stopper. BTW, I used 33Ks between the turret and the socket.

On the original schematic C25 is .033uf and is on the new Vibrato schematic which is C42, but a note stating .047uf in red appears as well.  Any reason for the variation or suggested different value?

Yes. The schematic shows a .033. Another schematic I have says it's .005 and I didn't believe that. So, I checked on another forum to see if anyone knew the real value. One guy posted a closeup pic of his REAL 1960 AC15. The cap (and it's original) in his amp was really .047! .033 and .047 are close enough for me. I put a .033 on my board just to keep to the original schematic.

So you just have a Switchcraft 12a connected to ground to enable the oscillator?  I can only see one wire, which I assume is grounded and the FS will open and close it if you decide to use one.  I usually end up not using a FS as I do not see myself using the VIB channel with the Vibrato/Tremolo off.  Come to think of I may put a switch along with the jack, but I remember the normal channel so great with the EF86 I think it may not be any value to even turn off the VIB/TRE.


I guess you got a second wind.  It is still fun even though I only ever need one more amp.  This one does it for me.  I will only mod the ones I have from now on.

[sluckey]

Well, I lied! It's raining today so I opened the shop and turned it on. SURPRISE! Everything works exactly as it's supposed to. This layout is now proven. The amp is quiet when it's supposed to be quiet.

The trem/vibrato is wonderful. IMO the trem beats the Fender harmonic vib in my revibe. And the vibrato really is a true pitch shifting vibrato. However, it only has one modulator stage so it's not as lush sounding as my Maggie M10A. And it doesn't have the chorus like effect that I can get from my Warbler which has three modulator stages. Still a nice sound though.

The trem effect is stronger than the vibrato effect so you have to twiddle the depth knob to match intensities. Don't know if that's a design character or a flaw.

The EF86 channel is louder and more in your face than the vibrato channel. And the Brilliance switch is very bright. It would be an improvement to replace the SPST Brilliance switch with a 6-position rotary switch with a variety of caps.

One of my concerns was would that 22K/3W resistor feeding node D hold up. Not to worry. That resistor only dissipates 0.6W so a 3 watter is fine. Ed, get those blue 3 watt metal oxide resistors that Doug sells and they'll fit your board nicely.

I'll be doing some scope testing, signal tracing, and voltage checks in the next few days to see if I can determine if the amp is really working well. More work has gone into this project than any before. So far, I'm very pleased.

There are a couple things I would change if I were gonna do this again.

1. Move the board 1/4" farther away from the pot side of the chassis.

2. Try to space the controls on 1 3/8" centers. My chickenheads are too close and are constantly running into each other. I've already changed them to avoid that, but I really liked the way the chickenheads looked on the front panel.

I'm gonna post one more pic that may be of some use to Ed and lego, or anyone else that choses to build this. This is the ground scheme exactly as implemented in my amp...

EDIT... big pic removed.

[Ed_Chambley]

What speaker and cab did you try?


Moving the board closer to the tube side/  Reason?  I am using an 8" chassis.


Does the cut not kill enough highs or you just mentioning a rotary for different tonal options? 


I have some cream 7/8 chicken heads on a build that look nice.  I was planning round cream fender knobs anyway since my opening is only just at 2".


2 watt should be fine for the 22k, shouldn't they?  I have some.

[tubenit]

Sluckey,

I hope this thread will be appropriately edited down to the basics and put into ARCHIVES at some point!

Bravo on the build!  Thanks for sharing your success.

With respect, Tubenit

[sluckey]

What speaker and cab did you try?

So far all I've tried is my 15" Eminence Big Ben.

Moving the board closer to the tube side/  Reason?  I am using an 8" chassis.

Just to give a little more breathing room for the input jacks.

Does the cut not kill enough highs or you just mentioning a rotary for different tonal options?

Cut works very well and if you hit the bright switch you will have to use it. I have a 6 position switch on my AC-15 Lite and it is a big improvement over the stock Vox Brilliance switch.

2 watt should be fine for the 22k, shouldn't they?  I have some.

If I had some I'd use them. If I had to buy some I'd get 3 watters.

[sluckey]

I hope this thread will be appropriately edited down to the basics and put into ARCHIVES at some point!

I wouldn't even know where to begin. What's important and what's not important? All the big pics have been removed so it's pretty much a text only thread now. And the ground scheme I just posted exceeds Doug's 'pixel' limit so I'll take that down as soon as I think all interested will have it.

Jeff, you've done a great job putting things in the archives. Wanna take the challenge? 

I plan to put this project on a page at my website whenever this numb feeling disappears. I plan to tell the whole story, including Barry's part. And all my big pics that used to be in this thread will be there. Maybe even some new ones.

[lego4040]

Steve I'm stoked your amp sounds fantastic and since mine isn't in chassis yet maybe I will go and do that. All those pics were mine and I'll be glad to resize and post them if we put it into archives. I have a rotary switch from bigdog guitars and can use that but change caps

[Willabe]

She Fly's!!!!!!!!!       

The trem/vibrato is wonderful. IMO the trem beats the Fender harmonic vib in my revibe. And the vibrato really is a true pitch shifting vibrato. However, it only has one modulator stage so it's not as lush sounding as my Maggie M10A. And it doesn't have the chorus like effect that I can get from my Warbler which has three modulator stages. Still a nice sound though.

That's great news!

Well now I have to build a 3 or 4 stage vibrato based on this amp that's just a standalone like the Warbler. I started to lay it out last year and posted what I had on this thread. But now I'll have to look at your layout and see if that will take less space over all. I think it does.


            Brad        

[EL34]

I hope this thread will be appropriately edited down to the basics and put into ARCHIVES at some point!

I wouldn't even know where to begin. What's important and what's not important? All the big pics have been removed so it's pretty much a text only thread now. And the ground scheme I just posted exceeds Doug's 'pixel' limit so I'll take that down as soon as I think all interested will have it.

All you have to do is post reasonably sized images and you are good to go
In focus, not too dark, cropped so that you only show what is of interest
A bunch of the images in this post were way too large with way too much non-subject matter surrounding the actual thing of interest.

Steve you have a ground scheme image that is larger than 1024 pixels or 800kb?

Click the images below to see how wide 1024px is
The top image has a bunch of wasted white space above and below the actual text
The bottom has been cropped, for those that don't understand what I mean by cropped

[sluckey]

Steve you have a ground scheme image that is larger than 1024 pixels or 800kb?

Yes. The file was actually 1754 x 580 pixels. I know that's a wide pic for a cellphone. But the chassis is 20 x 6.5. In order for the ground scheme to be readable the pic has to be wide. However, this is a moot point. The actual file size was only 66KB. So I came in way under your file size limit, but exceeded your 1280 pixels wide limit.

But no matter. The people I wanted to see it have done so and the pic is gone now.

[EL34]

lego4040 PM'd me and said he downloaded a image re-sizer app for his phone?

I don't know much about that since I have never owned a cell phone. 

send me your image by email Steve


EDIT:
I found a really cool web app that can crop and re-size images and it is very easy to use
Check out my tutorial on this page


http://el34world.com/Forum/index.php?topic=464.0

[lego4040]

EL34 I worship that you don't have a cell phone. For those with iPhone I got a free resize app and resized to the smallest size then uploaded to photobucket. If someone wants some of my photos I can send them to you directly so they don't eat up Doug's server space.

[EL34]

Thanks, but go ahead and post your images.
Posting images is not a problem if they are kept to a decent size


Just follow the guidelines on this page
I just did a tutorial that I hope people will like

Re-sizing an image is only the second step
The first step is to crop out any external stuff not important to the main image
Then your main subject will be as large as possible in the image

http://el34world.com/Forum/index.php?topic=464.msg168926#msg168926

[lego4040]

I always try to remember to crop out the crap. I was by the Hammond factory but no time to stop in. This last photos by Sluckey show me how to place my trannies.

[EL34]

I like that


Crop out the crap! 

[lego4040]

Thank you, I tried getting my mother in laws  new "smart tv" going  got it going just in time for BlackHawk Bruins Game. I've been reading some of the book I posted a picture of and what's I fiend interesting and I am thinking about is why do I or why would I want a tube rectifier when I can use four diodes? and create my DC. The book doesn't get very techie at all but I think I need to find another book that gets more detailed, so I fully understand and chew on a theory for awhile.

[sluckey]

There is an error on my schematic and main board layout. The resistor that connects to V5-8 is shown as 2.2K. It should be 1.5K.

The value difference is insignificant because V5B is a unity gain phase splitter. Changing the resistor will accomplish nothing as far as circuit performance, but it will make the circuit agree with the original schematic. I'm gonna change the resistor just because I'm anal about it!   

[Ed_Chambley]

Thank you, I tried getting my mother in laws  new "smart tv" going  got it going just in time for BlackHawk Bruins Game. I've been reading some of the book I posted a picture of and what's I fiend interesting and I am thinking about is why do I or why would I want a tube rectifier when I can use four diodes? and create my DC. The book doesn't get very techie at all but I think I need to find another book that gets more detailed, so I fully understand and chew on a theory for awhile.

http://www.ozvalveamps.org/jackdarrhandbook.htm
Here is jack Darr's book free PDF


Designing Tube Preamps for Guitar and Bass, just search.


London Power, Kevin O'Conner's series of books.  These seem expensive, but I finally got a couple of them and while they are not technically hard (which I like) they are just packed with information on modifications.


Gerald Webers book, hip desktop guide is good for the trainwreck pages and for modding fender amps.  The Super Reverb mods are nice.


No sooner the I began to understand Bias Vary Tremolo, this Vox thing came along.  I still look at the schematic and think what the $*@!.


Then there is always the RCA RDH4 which is free and located in Doug's Library and then there is Doug's library, which you may already know, but I bet you can still pick uo a thing or 2.


My favorite is Merlins Designing Tube Preamps for Guitar and Bass as he leans towards pentodes.  It is a really good reference book.  For instance, he gives you a multitude of ways to make different voltage dividers which has helped me shoe horn in extra tubes in preamps.


I am playing with a preamp design for about 9 month that has 4 completely different preamp tubes and his book helped me setup each stage keeping the gain controllable.  If I had to guess, I believe it is probably the most popular here on the forum.


Personally, I gained more understanding from Jack Darr's free book than any, but that I how I learn best.  Some are more visual and I remember Silvergun mentioning the Greald Weber video helped him a lot.

[Willabe]

London Power, Kevin O'Conner's series of books. I finally got a couple of them.....

Which 1's?


                Brad   

[Ed_Chambley]

London Power, Kevin O'Conner's series of books. I finally got a couple of them.....

Which 1's?


                Brad   

4 and 6.  Got them off Ebay, but I have not had a chance to crack them open yet.  A quick flip through and it looks like #4 is probably the best for those who already have some knowledge.  They are dog eared and dirty, but still very useable.  I plan to buy some more, but I have more books than I have time.    I got them specifically because of you and it is your fault if I don't like them.


Let's see, I am reading RDH4 a lot.  Building this Vox and making cabinets.  On my KT88 build, I am still not happy with the grill cloth, so I have some new stuff I am going to use soon.  I have a 5c1 Champ I robbed the cab for a 5e3, it has a 12 celestion blue and I need a cab for it.  I really like that amp a lot and it was my first true Point to Point build.  You get the idea.


I am doing the Vox now because Sluckey is leading the way and working out all the bugs.  How cool is that?

[Ed_Chambley]

There is an error on my schematic and main board layout. The resistor that connects to V5-8 is shown as 2.2K. It should be 1.5K.

The value difference is insignificant because V5B is a unity gain phase splitter. Changing the resistor will accomplish nothing as far as circuit performance, but it will make the circuit agree with the original schematic. I'm gonna change the resistor just because I'm anal about it!   

Not really a comment on the resistor, just wanted to get your attention.


You added the depth knob, but made this comment.


The trem effect is stronger than the vibrato effect so you have to twiddle the depth knob to match intensities. Don't know if that's a design character or a flaw.
I do not remember switching the Trem and Vib back and fourth nor do I remember if the original had the same intensity when switching.  The depth pot is a modification.  Is this a problem?  I don't have the original schematic handy so I don't know if the 1MA pot replaced a resistor or how you calculated the modification.

If the tremolo is simply stronger, then on the original amp it would have to been intended to be this way since no depth adjustment.  I am just wondering if the pot has the same effect on both.  I believe the pot simply controls how much of the modulation effect returns to the PI, but is it replacing a resistor in the Vib and not in the trem?

Just guessing as I do not understand how it could be different unless designed that way originally and I do not remember anything being off between them and I certainly am not second guessing your work, just trying to understand.
[/color]
[/color]

[Willabe]

I got them specifically because of you and it is your fault if I don't like them.

             


Those are the 2 hardest to read IMO, still good stuff. They have all the Power Scaling and compression/sustain stuff in them plus master volumes and high gain chapters. 1 and 3 is the most helpful. I'm still glad I have all of them, but I think 1 and 3 covers a whole lot of ground for most people.


            Brad     

[lego4040]

Thanks for that Ed, I'll put that in my zip and download. Maybe print it out and have it bound

[sluckey]

The depth pot is a modification.  Is this a problem?  I don't have the original schematic handy so I don't know if the 1MA pot replaced a resistor or how you calculated the modification.

The mod is not the reason for the difference in strength of the tremolo versus the vibrato. Open the visio file. Do a new window and arrange the windows side by side. Now put the original schematic in one window and my schematic in the other window. You'll quickly see the very minor changes between the two circuits.

And you can correct notes 2 and 3 while you're looking at it.

[Backwoods Joe]

My experience has been that the Tremolo by it self is stronger than the Vib/Trem together (for the same depth setting).
And the depth (intensity) pot (as Sluckey has on his layout) controls the the tremolo as well as the Vib.

[Ed_Chambley]

The depth pot is a modification.  Is this a problem?  I don't have the original schematic handy so I don't know if the 1MA pot replaced a resistor or how you calculated the modification.

The mod is not the reason for the difference in strength of the tremolo versus the vibrato. Open the visio file. Do a new window and arrange the windows side by side. Now put the original schematic in one window and my schematic in the other window. You'll quickly see the very minor changes between the two circuits.

And you can correct notes 2 and 3 while you're looking at it.

Already did and I see what you mean.  They are identical or as close as anyone would want. 


Backwoods Joe knows.    Vox amps I mean.  I do not remember the difference so it must not be an issue.

I am about 3/4 finished with loading the board.  Man alive, now I understand why we have PCB.


If going nicely and I may have a photo or 2 soon.  I ordered caps that I knew would fit, but I wanted to use up spme SoZo yellows and they are fitting nicely, even the .1's.  It really is a nice layout and I have plenty of room to solder.


I have a couple of parts I am still waiting on and I am getting some different Teflon jacket single strand I have been wanting to try.  Still have not started on the chassis as I am taking my time.

[sluckey]

Here's another change I had to make while testing today...

The 100K on the speed pot is too small. The oscillator will quit when the speed is turned to maximum. Replace the 100K with a 220K to fix.

[lego4040]

  noted.

[PRR]

> those that don't understand what I mean by cropped
> Crop out the crap!

First image, while not over-size, has sink, stone, clothes, and other crap around the object of interest.

Second image has the crap cropped out.

[lego4040]

Nice Ibanez 

[sluckey]

Second image has the crap cropped out.

We obviously have different views about what is crap. I was focusing on the tattoo! 

[Ed_Chambley]

I can find way hotter stuff than this, but I remember when the forum moderators took the position that things like this could be offensive to other members. 

I am far from a prude, just wondering if we have changed our positions.   Positions!

[sluckey]

Raising a girl to the age of 25 will adjust your position on a lot of things!   

[Ed_Chambley]

Raising a girl to the age of 25 will adjust your position on a lot of things!   

Lowering my age to 25 will do the most for changing my position on this.