lego's spin on Sluckey's AC15

[Ed_Chambley]

That's easy enough, top side? Leg 1or 3.

Top when looking at the schematic. Right lug when looking at the layout. But regardless of your viewpoint, it's the outside lug that ain't grounded. I recommend trying it as is first. You may be happy just the way it is.

I've been kinda drooling for this cab with Blue lately. I really like the blonde pic...

     http://www.avatarspeakers.com/vintage%20g112.htm

I like Avatar cabs.  They do a great job and this one is very similar in dimension to a Vox cab.  Basically it is a single "Bluesbreaker" (Backbreaker) cab.


Are you talking Blue speaker and Blond cab.  That is what mine is, but it would be cool to do the red Vox version.  That Vox grill cloth works with everything.  Anyway, good selection is you have the bucks.  The headbox looks good too.

[lego4040]

So I want to hook up the speaker jacks, Im using Hoffmans 3 way rotary switch and the new Hammond 1650F. I want to be able to use all 3 ohms availble with the switch but I dont think I can?

[sluckey]

I want to be able to use all 3 ohms availble with the switch but I dont think I can?

Correct. You can't use that switch with that OT. To use Doug's switch you would need the new 1650FA 'easy wire secondary' OT.

I used two jacks and wired the OT for 4/8Ω. I can't do 16Ω without restrapping the OT. Sucks, don't it?

[lego4040]

  I wonder if using a DPDT switch you can go between 4&16 ohm? I stare at these lines to long my eyes get buggy and I get a headache. I'm all wired up now except speaker jacks

[sluckey]

Wire it like I did and deal with it later if you feel the need. You need to get that amp fired up and start gettin' some satisfaction! 

[lego4040]

Tomorrow I'll fire it up :icon_biggrin:of coarse on the current limiter first

[sluckey]

I wonder if using a DPDT switch you can go between 4&16 ohm?

Here's a possible solution using a DPDT toggle switch. The pic shows using 3 jacks for more versatility but if you only want to switch between 4 and 16, just eliminate the 8 and 16 jacks.

[Ed_Chambley]

Tomorrow I'll fire it up :icon_biggrin:of coarse on the current limiter first

Firing up tomorrow.


Ya!!!!

[lego4040]

Amp is up and running, I did the poor mans variac and it's good. I'm taking some measurements now. 275vac on secondary and 335ish on rectifier pin 3

[lego4040]

  Hats off to Sluckey, I only played amp thru a 8" old speaker mounted in a cardboard box(bench test speaker) and this amp blew me away. At first I couldn't get vib to work and then remembered Eds dilemma. I stuck a jack in it and shorted the tip n sleeve and was in a time warp. Dual board version is verified baby. I took measurements were they were noted in Sluckey's schematic. I will post my measurements

[sluckey]

Outstanding! That really looks professional lego. We want to see some gut shots too. Bet your friends over on BYOC would like to know what you've been up to.

[sluckey]

At first I couldn't get vib to work and then remembered Eds dilemma. I stuck a jack in it and shorted the tip n sleeve and was in a time warp.

If you use a Switchcraft 12A (like the input jacks) and wire the switch lug to the ground lug the VIB/TREM will be enabled without anything plugged into the footswitch jack.

[Willabe]

Outstanding! That really looks professional lego.

Yes!!!!!!

We want to see some gut shots too.

Yes!!!!!!


                           Brad     

[lego4040]

I did use the 12A jack and will make that change, my vib and tremolo is reversed? I'll just flip switch. I cat believe the sound, on 2 it's sweet. Can't wait to crank it out

[sluckey]

OK, I just gotta know. Could you have squeezed this into a 17 x 6.5 x 2.5 chassis?

[lego4040]

With the two board version I built, all that open space with no board on top, I think you can have that in a 17" chassis. I am no pro builder but w careful thinking if where trans can go! Things will have to be carefully layered but I can see it. Your single board was 13"? You then have that space where my caps are for trannies, you can rearrange tubes to be closer and power tubes perpendicular. I'm no specialist but if your thinking of figuring it out, it's worth it to me. I can't wait to put this in a home 

[Ed_Chambley]

Well there it is.   Great looking amp.




I will get some photos up soon, I have been busy playing it and rolling tubes, changing voltages fitting speakers and dampening the cabinet some.  I still have to install the channel jump switch, right now I am jumping with a switch and plug.


Soon as you get a chance, play some Credence (CCR) with the vibrato and use your Gretsch.  I used my 335, man it really gets the groove.

[lego4040]

I have to redo my rotary switch, only works on one value? I just might stick the standard switch in when I order it. I went blank on doing the voltage checking, I was so excited. I couldn't remember how to check the wattage and all that. I still have to try and remember how  

[lego4040]

Who had that link to the mini chicken head knobs?

[Willabe]

Here's one;

http://www.tubesandmore.com/products/P-K900


              Brad     

[sluckey]

Who had that link to the mini chicken head knobs?

I bought a set and took them off the next day. Too tiny for my hands. They also look odd on the amp. Might be fine on a stomp box.

[lego4040]

Sluckey, If you got to look at my readings do they look kosher? Thanks fo the link on knobs. Ill have to choose one sooner or later

[sluckey]

Sluckey, If you got to look at my readings do they look kosher?

Look about perfect to me.

[sluckey]

I couldn't remember how to check the wattage and all that. I still have to try and remember how

See reply #495 on page 10.

[lego4040]

I saved that page yesterday too, I just went blank once it fired up I did the footswitch wire change and thats done. I'm noticing my normal channel is louder then my vibrato channel, if i put vib on 2 and play then plug it in to normal on 2 its way louder. Also I noticed that whatever channel I am playing in and have the top cut on 0 and the other volume  vol on 0 I get a buzz. If I turn one of those to clockwise just a little it goes away. This is some of my findings as I play with amp

[lego4040]

Sluckey this is what I came up with. My meter was acting up on mv readings.

[sluckey]

You're fine. That 18 watts is for both tubes. That calculated 58mA cathode current splits thru the tubes. Hopefully it splits evenly so you would have to divide the total current by 2 to get the current thru each tube. Really not a big deal in a cathode biased amp.

I'll check on some of your other issues soon.

[lego4040]

I just went over some other readings about Biasing and the tubes did not get overheated while playing. Your a mind savior. Hopefully I'll pull the trigger on a cab and speaker. Anyone ever use Mojotone Speakers? They have a Blue British speaker that's mode in England at a reasonable price

[lego4040]

Ed you still working on adding reverb to the amp

[Ed_Chambley]

Ed you still working on adding reverb to the amp

Not going to do a reverb because it doesn't need one.  With the channels jumped and the normal volume up just over the vibrato, running the vibrato with some speed you get quite a bit of depth.


Truthfully, once I got it into the head box and the speaker mounted I have not done anything but play it a lot.  I love the amp.  Like I mentioned, I had an original and I was young and sold it.  I have another now.


I love the thing.  I am going to do a few more things to it, but I am waiting so I can do all at the same time.  I don't always use the tube socket, but I probably will.  I have been using the Belton Bricks for reverb some and they are great, but a nice loop is probably making the top of the list.


I read your questions about the speaker.  I have tried a few different ones as I have many speakers and can use any cab I want and I have some of the highest regarded speakers and I not going to use anything other than the Celestion Blue.  I know they are expensive and I own 4 of them and I would not sell any of them for less than $300 because they are broken in well.  The one I put in the cabinet I would not sell for that cheap as I bought it new about a year ago and have been playing it in a 2, 12 with a greenback for about a year.  I pulled it and put my oldest one back in.


The amp sounds better to me with a single Blue than a Blue and Greenback together.  I also have a silver Vox 10" and it breaks up too easily with the amp.


Just my 2¢ on the speaker selection.  There is a reason everyone with a Vox amp either has one or wants one.  I do not know of another speaker like it and I do have a couple of Weber Blue Dogs Alnicos.

[SILVERGUN]

Truthfully, once I got it into the head box and the speaker mounted I have not done anything but play it a lot.  I love the amp.  Like I mentioned, I had an original and I was young and sold it.  I have another now.

Now that's a success story.....

Great work guys!

Lego, I'd just like to thank you again for coming here and sharing your project, and kicking these old guys in the pants...
It has been fun to watch.

[Ed_Chambley]

Truthfully, once I got it into the head box and the speaker mounted I have not done anything but play it a lot.  I love the amp.  Like I mentioned, I had an original and I was young and sold it.  I have another now.

Now that's a success story.....

Great work guys!

Lego, I'd just like to thank you again for coming here and sharing your project, and kicking these old guys in the pants...
It has been fun to watch.

Did not take much to get me going on it either.  I believe Sluckey was the same way.  I think he has been wanting to see if the layout would work nice.  It is great and there is no heat problems.


I play a lot more than I build.  I really love building and modding amps, but I would rather play.  I have always bee that way.  I never get tired of it like some of my friends say.  I have been looking at camcorders and plan to get one soon so I can demo the builds I have done.  Until then just keep in mind I am just an old hack with some nice amps.


The amp is Killer playing anything, but really shines playing CCR and Tom Petty and the Beatles of course.  What surprised me the most is how great it is chicken picken with a Telecaster.


Did the guit ar chick like her dig her amp?  ready to build another just like it, or did you learn a few things and maybe change it up a little next time.


What do you think about the overdrive you had in a AC15

[SILVERGUN]

I play a lot more than I build.  I really love building and modding amps, but I would rather play.  I have always bee that way.  I never get tired of it like some of my friends say.  I have been looking at camcorders and plan to get one soon so I can demo the builds I have done.  Until then just keep in mind I am just an old hack with some nice amps.

I'm gonna have to eventually get back there....I put it down about 7 years ago, and now I regret that....
I'm looking forward to those clips

The amp is Killer playing anything, but really shines playing CCR and Tom Petty and the Beatles of course.  What surprised me the most is how great it is chicken picken with a Telecaster.

That's something I'll never know...tried it..I'll stick to chicken eatin' 

Did the guit ar chick like her dig her amp?  ready to build another just like it, or did you learn a few things and maybe change it up a little next time.

Check the thread...I finally updated it

What do you think about the overdrive you had in a AC15

What overdrive? 
That's one thing that's open for interpretation around here....one man's overdrive is another man's clean channel 

[sluckey]

...I'm noticing my normal channel is louder then my vibrato channel, if i put vib on 2 and play then plug it in to normal on 2 its way louder.

Also I noticed that whatever channel I am playing in and have the top cut on 0 and the other volume  vol on 0 I get a buzz. If I turn one of those to clockwise just a little it goes away.

The normal channel is considerably hotter than the Vibrato channel. Ed and I both noticed that. I don't think there is anything wrong, just the nature of the EF86 channel.

I don't have the buzz. Will you ever play the amp with the cut at zero? Zero cut is really max cut if you wired the pot IAW the layout diagram. IOW, as you turn the cut clockwise the tone gets brighter.

[lego4040]

I'll never play the amp at zero so that weird issue won't be a problem. For reverb I built two beltin brick pedals myself, one is the BYOC reverb and the other is a rub a dub that I have in my rockabilly box this pedal is a multiplex junior(echo,delay)/reverb/modulation/llama overdrive

[lego4040]

Sluckey I made that speaker out to your design I got I shorten the yellow wire tomorrow. I took a break and built another CBGand go plugging for stripe bass and blues

[sluckey]

I'm thinking strongly about doing that too. It always bugged me to have a 16Ω tap that was not easily usable. There have been so many little mods that keep popping up with this amp that I may put together a pdf just to keep track of it all. If I do I'll let you know.

Did you catch anything?

[lego4040]

I caught peace and tranquility for about 2 hours, no fish. I'm working on getting all my get back in order, nothing like battling a big blue fish or striper. My family are all fishermen and we would eat all our catches. I need to rewrite rotary, I screwed up wiring and only one selection works. Its taking me forever to pick a cabinet, I was thinking a standard mojo Marshall style and mojo British blue. The only thing with that is the faceplate will be backwards the way the tubes are

[moonbird]

Hi all -


Very late joiner here. Wow a proven AC15 clone! Great work guys. Wow Sluckey 

Do you think Doug might cut a CNC board for this beauty?? Hope so!!

[sluckey]

Do you think Doug might cut a CNC board for this beauty??

Sure. Just click on the link at the bottom of this page to create your own board. Then Doug will use it to create a file to control his CNC. You can use my drill guide to mark the turret locations in Doug's program. Just keep in mind, his board will be longer than my board because the distance between adjacent turrets is greater than my .25" spacing.

I don't know if Doug can directly convert my drawing to a file suitable for his CNC. I'll ask him.

[lego4040]

Sluckey I redid the speaker outs, L>R is switch,4,8,16 ohms. I pulled out rotary switch, tested and all worked. I put it back and had issues. I pulled it out and and bypassed it for know. It plays so sweet I'm just gonna go back to original switch wit 220pf. Here is the back

[sluckey]

I sure do like the looks of that dog house. Just looks like it belongs. Every time I see your amp I feel like I should do one more, but stuff it in a 17" box.  Still wanting to do the speaker jacks like that too. I know I'll probably never use a 16Ω tap, but it just bugs me having one that's not available.

Don't give up on the tone switch. It's got to be something simple.

BTW, I'm really liking the sound of this amp through the 8" Vox speaker in my 'stuffed vox' project. Makes me really want that Avatar Celestion Blue cab.

[lego4040]

I won't give up on switch, I counted the six pins on top and Six on bottom, although they don't exactly line up like your picture. There isn't a pin directly above or bellow where the leads from amp and to vol pot go.  I will install the Power plug like you have, I did it the other way with plug Always connected and it's a pain in the butt to deal with on the bench. I'm heading over to avatars site again now. I should sell my 1930's Dobro and go get me a 2x12 cab combo

[Willabe]

I should sell my 1930's Dobro

Whoo!!!! Back up the buss, hold the phone!!!!

Old Dobro, send me a PM please!!!!


                  Brad     
                 

[Ed_Chambley]

I won't give up on switch, I counted the six pins on top and Six on bottom, although they don't exactly line up like your picture. There isn't a pin directly above or bellow where the leads from amp and to vol pot go.  I will install the Power plug like you have, I did it the other way with plug Always connected and it's a pain in the butt to deal with on the bench. I'm heading over to avatars site again now. I should sell my 1930's Dobro and go get me a 2x12 cab combo

What are your thoughts on a 2 12 cab?  Are you needing more volume or do you just want to mix and match speakers.  Mojo builds a 1 12 british style.  It is just like a 18 watt 2, 12 marshall only a single 12.


I have tried many different combinations of 12 inch speakers and found I prefer the Celestion Blue.  The Blue speaker has a more mellow upper mid and highs and compress easily and IMO is the Vox tone.  I tried it with two of them and I got enough volume to Gig it.  With a single 12 you cannot get up over a drummer with a clean, it breaks up some. 


What does work is using a NOS tesla EF86 on the normal channel with Amperex Holland NOS.  The amperex keep a clean signal and a higher volume than any I have tried.  Much more than JJ.  The character of the JJ's is very similar to old RTF's which I really like because they breakup early and do it nicely.


In the wiggle channel the RCA nos 12Au7 is a clear winner as it makes for a much more distinct Vibrato.  In the first hole a 5751 will make the normal channel have more volume before breakup and if you can get a Black Plate it is very nice.  Still the normal channel is much louder especially with the tesla.  A mullard NOS as usual has the mullard sound.  very round very smooth.


This amp responds to different tubes very much and in reality a whole set of new production work well.


On speakers since you are at 18 watts listen to some of Dr Z Maz
Dr. Z MAZ 18 Jr 1x12 Combo Amp Demo


They have speakers made for them, but looking at them and the sound is very much Greenback Celestion.  They chime, but I cannot hear any of the bell tones, but I have a Blue in a Tweed Deluxe build and it does have the bell tones.


Not trying to convince you on speakers because everyone likes different speakers, but putting a greenback with a blue in the same cab does not allow the bell tones to be cleary audible.  On the other hand I paired a Blue with an old Jensen p12q and this paired up great.

[lego4040]

Damn Ed, that's a chock full of info for the tube rollers. I do feel the vibrato is a little weak and could stand for a fuller vib, tremolo is perfect. I was joking about a 2x12, I'll never use or need it. I'm thinking the mojo 18watt Marshall cab. I don't know if this chassis (my cab has the ears out the side and make it 21 1/2".) hopefully not a lot of finagling and the chassis bolts will line up. Will that 12AU7 break the bank?

[SILVERGUN]

listen to some of Dr Z Maz

How bout that riff at 1:24?
I'll be stealin' that one for sure.

Thanks again for sharing all of your experience Ed....
Your like the E.F. Hutton of speakers.....please don't ever stop typing.
I never would have thought that I would be diluting the beauty of one speaker by mixing it with another....I always just pictured getting the 'best of both worlds'
Someday I'll hit the lottery and buy me and lego one of those Blues.

[Ed_Chambley]

The idea of the best of both worlds is a definite possibility in speakers, but this is why I prefer a center board in a 2, 12.  That being said, it is impossible to keep the from mixing in front, but it helps.  The Jensen speaker in the 2 12 setup I tested really shinned in the mids.  I am not a big fan of Jensens, but some amps really love them there is no denying that.  They always bring a vintage feel.


Here is why it works.  The Jensen is not as efficient and the highs naturally become more apparent as efficiency rises in speakers (generally speaking, there are intentional exceptions).  The Jensens added a vintage feel in the mids and are not as efficient, so did not overpower.  Similar to using the same speaker, you get more of the same things, but here you get more of a different thing while keeping the Celestion Blue in-front.  Don't tell me about costs.  Everyone who complains about the cost if Celestion Blues has wasted more money than that testing cheaper speakers.  Here is a thought.  have you ever heard anyone say they did not like them?  Craigslist is your friend, sometimes.  Do not be afraid of blown ones either which I find often.  Orange County speakers will recone them using original parts and after breakin you cannot tell the difference.


Sorry as I feel like I am hijacking, but we are building amps that need speaker discussion.


Lego- a 12AU7 is cheap.  You can still find new in box RCA on ebay for less the $20.  No one is really looking for them.  I bought 10, 2 5 packs from a guy at a Hamfest for $3.  They are RCA black plates which really doesn't matter in this slot.  Just a good NOS tube will do.

[lego4040]

  Spent over another hour with that    rotary switch, Im done. I'm gonna order the regular switch and keep that original. I tightened up pins in the ceramic tube holders, they felt loose. Played some more and noticed when in vibrato channel the normal volume acts like a master vol. I don't remember if its supposed to do that. It plays perfectly Sluckey. I have to cut slot for the IEC plug. Im done for today, time to get ready for hockey game.
LETS GO RANGERS

[lego4040]

I lied, I had to get the plug done, it was irking me. I didn't wire it in but it's in