lego's spin on Sluckey's AC15

[lego4040]

I added the cascade today

[Ed_Chambley]

Oh Ed, you just hard wired your amp for the cascade or did you use switch?

Just wired, no switch.  I had it on a 2 button Footswitch and found after playing I was using it all the time this way.  I remember when I had my original 63 I kept it jumped.  It really does not add much difference in tone it just makes everything available all the time.


I wanted to play it for a while as I knew it was going to be one of my 2 main amps.  I always use 2 as I have mentioned many times.  I have a 6V6 amp with 2, 10's.  It is based on the AA1164 Princeton Reverb which I use as my "Wet" amp and the Vox is now my dry amp since it distorts very easily.  The fender style amp has much more headroom and is much cleaner which IMO sounds much better with pedals.


Wrote that to say I have not done my final tweaking.  I don't really like Mods on an amp just for the sake of it.  If I do not use it in a live situation I do not add the mod because if I am recording I simply use another amp with the sound I really want.  I have found the Brilliance switch to be great with added flexibility.  Moving the footswitch wire for instant on wiggle is a good mod as well, if you want to call it a mod.  Slowing the tremolo and I changed the pot from Audio to linear because of preference.


So after using it for a little while this is all I want the amp to do because it does it very well.  It is really nice combining the 2 amps.  I have been working on a design for a long time that uses 2 EL84 and 2 6V6 and this has really helped me as I have never really focused on the EL84 much.  What is interesting is I much prefer a split load PI on the 6V6, but I prefer a LTPI using EL84.

[lego4040]

I cannot for the life of me wire that rotary switch correctly   I have a problem with all those tabs and getting them correct. I would like to put it on the vox tho. I am digging thru parts for the Stout as my next project

[moonbird]

For the past two weeks I've been playing all my amps thru a Weber 12" California

Sluckey - Does your California speaker have a metal dome? Is your Leslie cab on your website somewhere? If not, would you mind describing what you did with it? I have a couple of Model 122 cabs (no horns) that would be fun to play with.
BTW - I am about 60% done with the board for this amp. Hoping to join you all in narvana soon!! 


FWIW - I think this thread is great - been very inspiring to me!! Thanks to lego (hope the health stuff all works out well!!).


Thanks.

[sluckey]

Does your California speaker have a metal dome? Is your Leslie cab on your website somewhere?

Yes, I have the aluminum dome. It sounds very bright (I might say ice pick bright if I had good ears) with a strong bottom. The Leslie cab tames the brightness considerably, much more than a regular speaker cab. I just put the project on my website today.

BTW, I'm not advocating pairing a Weber Cali with the AC-15. I still want a Celestion Blue for the AC-15. But, the AC-15 just happened to be on the bench when I started the Leslie project. So, it's had a good workout thru the Leslie. I do think the Weber Cali is a good choice for the Leslie though. Of all the amps I've tried with the Leslie, I like my AB763 TDR best.

http://home.comcast.net/~seluckey/amps/leslie/leslie.htm

[moonbird]

Sluckey -- Great info thanks very much for posting! I also have a 12" Cali with "the dome". Have had trouble finding a good home for it - sounds like I found it!!

[lego4040]

Steve I borrowed your idea and cut some flooring down and put a coat of concoction on it. This is the old faceplate on it and I have some other ideas to pretty it up. I might want to add a top cover of sorts.

[sluckey]

Some things don't need to be hidden in a box. That looks pretty classy. It's just right to show it off. 

[lego4040]

Thanks, I'll finish plate this week and hopefully get me some wood for Your AC head

[lego4040]

A little prettying up, I haven't had much time to do anything lately except this quarter round stained atop off pan

[sluckey]

...If there are no photos or sound clips, it did not happen so the one I have does not make a sound if it falls in the woods.

Will we ever get to see or hear your AC15?

[Ed_Chambley]

Yes, I will get it done.  I have been putting off taking it apart, but I have been recording.  It is just a crappy version of yours!

Problem is I am lazy with the photos and move onto other things.  I have been playing the snot out of the thing.  I will take it apart and get some photos of the Lead dress so you can get that feeling of arousal.  You want cabinet photos as well?

Actually, I have built 4 amps since that one, but it is the most special and turned out really good and now I am doing some layouts for the new EL34 builds.

[SleepLess]

Hi.
Has anyone of you posted a video or soundfile somewhere to hear or see these Sluckey's AC15s?
What budget did you guys invest on this project (just the working chassis, not the cab and speaker(s))
Thanks! After a Revibe build, this looks like my next project... 

[sluckey]

I haven't seen/heard any sound clips. I used my Matchless Lightning as a donor and I had most other parts on hand. I only bought board material and a chassis. So I don't have a good idea of the cost. Lego or Ed may have a better cost idea.

[lego4040]

This build will run you close to the 300-500$ range depending on how you chose your parts. You can spend 1.50 for a Mallory cap or 15 bucks for a Jupiter cap, it's up to you. The parts list page here http://hoffmanamps.com/MyStore/perlshop.cgi?ACTION=enter&thispage=Amp_AC15Parts.htm&ORDER_ID=!ORDERID! Give parts and total cost minus transformers and tubes. So with those added you will be in the 500+range. I can honestly say I don't need to build anymore amps since I built the AC15, it is heaven sent. I added the tremolo mod to drop the speed even more and I am blown away. I rebuilt my champ clone into Hoffmans stout and I just finished a hifi stereo tube amp for my home. Thanks Doug and Steve for this expensive addiction 

[SleepLess]

This build will run you close to the 300-500$ range depending on how you chose your parts. You can spend 1.50 for a Mallory cap or 15 bucks for a Jupiter cap, it's up to you. The parts list page here http://hoffmanamps.com/MyStore/perlshop.cgi?ACTION=enter&thispage=Amp_AC15Parts.htm&ORDER_ID=!ORDERID! Give parts and total cost minus transformers and tubes. So with those added you will be in the 500+range. I can honestly say I don't need to build anymore amps since I built the AC15, it is heaven sent. I added the tremolo mod to drop the speed even more and I am blown away. I rebuilt my champ clone into Hoffmans stout and I just finished a hifi stereo tube amp for my home. Thanks Doug and Steve for this expensive addiction 

Sweet. It is about the same price range as a Revibe then. The transformers are costlier though, even Hammonds. You seem to really like it. I have built all the Fenders and Marshalls (over 30) and a Trainwreck Express but no Vox yet... I'm tempted.
Good Lord, I'm getting started again...

Did you build it as a head or as a 1X12 or 2X12 combo? If so, what speaker did you choose?
Thanks!

[lego4040]

I built mine for a head but still haven't gotten one for it. I am using a 12" for it now, it's made by VOM(guitar warehouse) and I can't complain. Sluckey swears by his 12" celestion blue after trying the amp with different speakers but that is close to 300 by itself. I love the Revibe I built, I had an issue with it but it was a matter of finding the right tube for V4

[SleepLess]

I built mine for a head but still haven't gotten one for it. I am using a 12" for it now, it's made by VOM(guitar warehouse) and I can't complain. Sluckey swears by his 12" celestion blue after trying the amp with different speakers but that is close to 300 by itself. I love the Revibe I built, I had an issue with it but it was a matter of finding the right tube for V4

I have a big 1X12 cab with an EVM12L. I may build this AC15 as a head as well. It's safer for tubes as well and avoid some vibrations on the components. A small 1X12 or 1X10 combo would be easier and more portable though. I also have an old EVM10S at hand. Oh well... So many possibilities, so little money... 

What I'd be interested in knowing is the dynamics of the amp and its headroom. Does it distort soon or can you really have lush cleans with it? I mean with small wattage amps generally they sound great between 8 and 10 on the guitar volume knob, but if you go below 8, the sound gets really thin and bad. You lose all the body of the sound. You don't get that with 50w amps and above. With a 100w amp you can use your guitar volume between 1 and 10. It's actually easier. With a 15w, your rhythm sound is on 8 and your lead sound is on 10. That's a very tiny space there and can be tricky to dial in while on stage. How does that amp behave in that regard? Is it good all the way?

Thanks!

[lego4040]

I haven't gigged the amp, I play it at home and my kin wouldn't be happy if I put this amp to 8. I will tell you it is LOUD and clean with that expected Vox sound. Did you read through this whole thread? Sluckey talks about his sounds and how it performs. Shoot him a PM

[SleepLess]

I haven't gigged the amp, I play it at home and my kin wouldn't be happy if I put this amp to 8. I will tell you it is LOUD and clean with that expected Vox sound. Did you read through this whole thread? Sluckey talks about his sounds and how it performs. Shoot him a PM

I read the beginning (pages 1 and 2) and the end (page 14)... lol. I will read through the 14 pages lego. Thanks!
Just to reassure you: my neighbours came knocing at my door yesterday to complain about "noise" (I quote them!) after seven minutes sharp of playing my tweed Champ 5F1 clone...  I had built it to avoid any complaints... 

[lego4040]

Even a champ is to powerful. You can build a 1/2 watt amp and get incredible sounds

[sluckey]

Sluckey swears by his 12" celestion blue

No, that's Ed. I'd love to have one based on his praise but so far I've just been too cheap.

Sluckey talks about his sounds and how it performs.

No, that's Ed too. I'm just a bedroom/shop picker for the last 35 years. I do crank it up in the shop occasionally and play for the neighbors across the street. I do like the way it sounds. I like the vibrato but prefer the normal channel.

I read the beginning (pages 1 and 2) and the end (page 14)... lol.

It's a looong thread. There are some nuggets scattered throughout the discussion but there's a lot of stuff like this reply. If you squeezed all the cream it would probably fill up one or two pages.

[lego4040]

Yes, it's a lot of stuff to look thru but it's a nice crowd here. My last build and I have a Hammond 290cax still in the box waiting for a home.

[Ed_Chambley]

I built mine for a head but still haven't gotten one for it. I am using a 12" for it now, it's made by VOM(guitar warehouse) and I can't complain. Sluckey swears by his 12" celestion blue after trying the amp with different speakers but that is close to 300 by itself. I love the Revibe I built, I had an issue with it but it was a matter of finding the right tube for V4

I have a big 1X12 cab with an EVM12L. I may build this AC15 as a head as well. It's safer for tubes as well and avoid some vibrations on the components. A small 1X12 or 1X10 combo would be easier and more portable though. I also have an old EVM10S at hand. Oh well... So many possibilities, so little money... 

What I'd be interested in knowing is the dynamics of the amp and its headroom. Does it distort soon or can you really have lush cleans with it? I mean with small wattage amps generally they sound great between 8 and 10 on the guitar volume knob, but if you go below 8, the sound gets really thin and bad. You lose all the body of the sound. You don't get that with 50w amps and above. With a 100w amp you can use your guitar volume between 1 and 10. It's actually easier. With a 15w, your rhythm sound is on 8 and your lead sound is on 10. That's a very tiny space there and can be tricky to dial in while on stage. How does that amp behave in that regard? Is it good all the way?

Thanks!

if you are planning to Gig the amp at 15 watts, you will have to be playing with a mature drummer and a nice sound system as it will need to be mic'd. 

It is Vox all the way.  I have tried many speakers.  Altec, Many Webers.  The amp needs a darker speaker like a Celestion Blue, but it sounds great with a Vintage 30.  A greenback is too bright.  EV's are too piano like for the Normal Channel and do not sound vox like.

I had an original 63 I sold many years ago.  It had all the problems.  I used a 1, 12" over-sized cabinet with a convertible back.  You can see mine here:
http://el34world.com/Forum/index.php?topic=17903.0

I use it for gigs along with a Fender based 2, 10.  It is close to the same wattage, but 6v6.

The EF86 channel does not have wiggle on it so you have to jump channels to get tones like Green River, but it does it well.

If I were planning to use it as a large gig amp I would add 2 more tubes and get a 30 watt OT with 8 and 16 ohm taps.  Then I could have a 2 12 cab for 30 watts and pull 2 tubes and use a 1 12 for 15 watts.

[lego4040]

Ed I didn't have a chance to read thru that link to much but who made that sweet head for you AC15? I want to leave mine out but with kids in the house I don't want to until it has a home

[SleepLess]

Thanks Ed for your insight on this build! Yes I plan to rehearse and gig with it. I don't think I need an AC30 it would be too damn loud. I play in small clubs with no more than 100 persons. Most of the time, they're only 50. I would kill everybody with an AC30. We do have a PA system and I always mike my amps, even when I play loud ones (30 watts and above). I use a Sennheiser E906 for that and we have EV PA speakers.

What about dynamics Ed? How does it respond to playing with the guitar volume knobs? Does the sound collapse below 8/10 on the guitar?

I know the EVM12L is neutral. Some hate them for that reason, I love them for that same reason. The fact that they don't colour the sound of the amp at all is what makes me love them. Plus the fact that with 200w of power a single unit can handle any amp. I don't need two or more speakers to handle a big Marshall 100w amp. My 1X12 with my EVM12L is good enough!
Well, I need to save a little and then I'll launch this AC15 project. I hope Hammond offers a EU PT, I need 230V here.
Thanks again!

[Ed_Chambley]

Thanks Ed for your insight on this build! Yes I plan to rehearse and gig with it. I don't think I need an AC30 it would be too damn loud. I play in small clubs with no more than 100 persons. Most of the time, they're only 50. I would kill everybody with an AC30. We do have a PA system and I always mike my amps, even when I play loud ones (30 watts and above). I use a Sennheiser E906 for that and we have EV PA speakers.

What about dynamics Ed? How does it respond to playing with the guitar volume knobs? Does the sound collapse below 8/10 on the guitar?

I know the EVM12L is neutral. Some hate them for that reason, I love them for that same reason. The fact that they don't colour the sound of the amp at all is what makes me love them. Plus the fact that with 200w of power a single unit can handle any amp. I don't need two or more speakers to handle a big Marshall 100w amp. My 1X12 with my EVM12L is good enough!
Well, I need to save a little and then I'll launch this AC15 project. I hope Hammond offers a EU PT, I need 230V here.
Thanks again!

I ride the knobs a lot.  The normal channel with the EF86 is extremely sensitive and if pushed becomes very mid focused, you know normal pentode reaction.

The vibrato channel needs to be hit hard to break loose.  The tremolo and vibrato are very focused and the channel is tight but the EL84's still distort easily as they will.

If you are playing pubs it is a cool amp.  I have played in very small rooms with it.  Being it is a head/cabinet I can turn the cabinet towards the wall so I can crank the amp then mixed at the PA.

[bonzerinc]

Hey folks-

I've been reading this thread for a few weeks getting ready to build one of these. I'm wondering about the difference between jumping and cascading the channels. Jumping puts them in parallel, so you've got them both at once. Cascading puts them in series, so you've got both at once with two gain stages. Could you use a sort of selector switch along with a series-parallel switch to be able to have all options (either channel on its own, both in parallel, or both in series) with a single input?

I tried to attach an image, but it doesn't show up in the preview, so I hope it works.

I've only made a couple of amps so far, both from kits that included fairly complete instructions. Those were a Tweed Deluxe and a JTM45+, both from tubedepot.com. I figure that, once I have a Vox clone, I'll have all the classic 60s amps I need. I may be in way over my head on this one, but it's time to go off road, so to speak.

Thanks,
Michael Bonner

[sluckey]

Could you use a sort of selector switch along with a series-parallel switch to be able to have all options (either channel on its own, both in parallel, or both in series) with a single input?

You could probably do it with a single input jack and this 3 pole 4 position rotary switch...

https://www.tubesandmore.com/products/P-H394

You may want to start a new thread if this project gets kicked off. Sometimes new stuff gets buried in long threads like this one. I'm interested to see what you come up with.

[Willabe]

Is this what the vibrato sounds like on the amps you guys built? (1st 30 seconds of the clip.)

I think it sounds great!

http://youtu.be/qOyvfdvGQCI



                     Brad     

[Willabe]

Is this what the vibrato sounds like on the amps you guys built? (1st 30 seconds of the clip.)

I think it sounds great!

No really, I wasn't trying to be funny.

I don't recall you guys saying the you liked vibrato all that much? (Maybe Ed did?) I seem to remember Sluckey saying he liked the Revibe he built as his favorite?

Maybe it's just me but I think that short clip of the Vox is a really great sounding vibrato.


                  Brad     

[sluckey]

Yes, that's the vibrato sound. The tremolo mode is more conventional but does sound better than Fender's roach or bias vary trem.

I played with the vib channel a lot in the beginning but then just kinda forgot about it. The vibrato effect is great (in fact, that's why I built this amp) but the lack of tone control makes the vib channel sound kinda ho-hum. I much prefer the EF86 normal channel to the sound of the vib channel. I think Ed likes to jump the two channels.

The AC15 vibrato sound is very similar to my Maggie, but I prefer the sound of my revibe over the AC15.

[Willabe]

running the vibrato with some speed you get quite a bit of depth.

So only sounds good or sounds much better at faster speeds, depth wise?


                    Brad     

[Willabe]

Yes, that's the vibrato sound.

Well I'll be, thanks. Nobody posted a sound clip so I didn't know.

(see the above post with quote.)


                       Brad     

[Willabe]

...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.

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.

The vibrato effect is great (in fact, that's why I built this amp) but the lack of tone control makes the vib channel sound kinda ho-hum.

In the trem/vibrato circuit, V1b only has 22K for a plate R. Couldn't V1a/b be set up like a Fender BF 2 stage input with a tone stack (B/T) ? Put 100K for a plate R on V1b with maybe even K bypass cap to help increase gain to make up for the TS losses? (Unless the K bypass cap will mess with V1b's boot strap?)

Might even have a little more gain then the Vox circuit did stock even with the TS?


                   Brad     

[sluckey]

In the trem/vibrato circuit, V1b only has 22K for a plate R. Couldn't V1a/b be set up like a Fender BF 2 stage input with a tone stack (B/T) ? Put 100K for a plate R on V1b with maybe even K bypass cap to help increase gain to make up for the TS losses? (Unless the K bypass cap will mess with V1b's boot strap?)

V1B is a standard cathodyne phase inverter (same as V6B). You need two equal amplitude but opposite phase instrument signals to work with the two opposite phase vibrato modulation signals.

I had looked at trying to increase the gain. V1A is about the only candidate and it's already running pretty high. Anyhow, it's not like there isn't enough gain, just that the normal channel is much hotter when the volume controls are set to the same number. It was just an observation and never really bothered me. I guess an easy fix would be to use a linear taper volume control for the VIB channel!   

[Ed_Chambley]

Yes, that's the vibrato sound. The tremolo mode is more conventional but does sound better than Fender's roach or bias vary trem.

I played with the vib channel a lot in the beginning but then just kinda forgot about it. The vibrato effect is great (in fact, that's why I built this amp) but the lack of tone control makes the vib channel sound kinda ho-hum. I much prefer the EF86 normal channel to the sound of the vib channel. I think Ed likes to jump the two channels.

The AC15 vibrato sound is very similar to my Maggie, but I prefer the sound of my revibe over the AC15.

I have the channels jumped all the time.  They are not out of phase either.

I am planning to install the switching for the cascode, but I am leaving the channels jumped.  With both you can use the EF86 preamp along with the wiggle for the pentode tone.  Really nice.

[Willabe]

V1B is a standard cathodyne phase inverter (same as V6B).

That's right, I know that.    But all cathodyne PI's are not the same in output. So if not signal voltage gain then current drive?

Anyhow, it's not like there isn't enough gain, just that the normal channel is much hotter when the volume controls are set to the same number.

Do you think there's enough gain to slip a BF T/B TS in between V1a and V1b?


                            Brad   

[sluckey]

But all cathodyne PI's are not the same in output. So if not signal voltage gain then current drive?

This PI is not being used for voltage or current gain. It's being used to develop two equal but opposite phase signals to work with the vibrato modulator.

Do you think there's enough gain to slip a BF T/B TS in between V1a and V1b?

No way. You would need a post gain stage just like the Fender amps. I got plenty of Fender amps already.

It was always my goal to faithfully reproduce the AC-15 circuit as far as the signal path is concerned. The only mod I have in the signal path is the 6 position Brilliance switch and both extreme positions function exactly the same as the original Brilliance switch. The trem mods only dealt with providing more control over the speed and depth. The original only had a 3 position speed switch and no depth control.

[Willabe]

Ok, thanks.


                  Brad     

[Willabe]

How about this? Think it will work?

For the cost of 1 extra 12AX7; BF TS- T/M/B, volume and 2nd stage of phase shift. (Not a Vox anymore but still usefull?)


                   Brad   

[Willabe]

It's being used to develop two equal but opposite phase signals to work with the vibrato modulator.

I think I see what I've been missing.

The modulator's 2 triode's are being turned on/off, opposite of each other by the LFO driver's plate and K. So because of that, it's 'picking' which R/C network from the plate or K (low pass/hi pass) from the preceding stage will be amplified.

So what I drew up only the 2nd stage will have phase shift/pitch shift vibrato because the 1st stage is not being modulated.

I printed up the Vox, 3 Maggies and Bandmaster 6G7A. Then I drew them all out along with the Warbler I already had drawn out, to study them.

I'll go back and print out what you wrote in your scrap book on trem/vibrato. I think I'll understand it a little better now.

My Gibby GA77 is all most finished, all I have left to wire up are the front panel controls. So I'm looking for something new to build.

I'll start a new post on this for a new build and leave this thread alone.


                      Brad   

[sluckey]

How about this? Think it will work?

That won't work. Coming out of the first cathodyne you are mixing the out of phase plate and cathode signals back together. Those signals will cancel (unless you are doing this to Ed's amp    )

For the cost of 1 extra 12AX7

For the cost of one less 12AX7, you could have a nice Dumble. 

So I'm looking for something new to build.

Are you wanting to use the AC-15 vibrato circuit in another type amp but also have a good tonestack too?

[Ed_Chambley]

How about this? Think it will work?

That won't work. Coming out of the first cathodyne you are mixing the out of phase plate and cathode signals back together. Those signals will cancel (unless you are doing this to Ed's amp    )

What is soooooooooooooo hard about adding a triode?  Maybe even a FET since it is a vibrato shouldn't HAVE to be a tube.

Also, how do you guys make those multiple quote sections?

[sluckey]

I just click the quote icon.

[Willabe]

Are you wanting to use the AC-15 vibrato circuit in another type amp but also have a good tonestack too?

Yes.   

I'll have to build it to hear it for myself.

I don't care about a pentode preamp gain stage and just want to play around with the vibrato channel.

I'm not big on EL84's, 34's or Dumbles or heavy gain or crunch. I listen to it, things with that tone sometimes but I don't really have a desire to sound like that. When I was in my 20's I did.     

I'll come up with something with 6V6's. 



                Brad     

[sluckey]

Looking forward to see your project.

[Willabe]

Thanks     

[TNblueshawk]

I know there is tons of funs in doing my own board but did Doug offer up the longboard version of this amp?
 
Whew, I just reveiwed all 14 pages, every word. That took awhile. I had to catch up and readjust my mind. Took a crap ton of notes. Now I have to organize my thoughts and plan. I need to sell a few things for some dough for this one....or listen to my wife go nuts again and just start stocking up on stuff   
 
I took a siesta from building most of last year (small amount of burn out) but man was my wife happy.
 
Oh, just a thought but for those that start new threads on this project it would be cool to link them to this one for ease of finding I guess. So if someone uses the search engine we know this one should pull but will all the others? I guess it depends on how good the search function is and that I don't know here since I haven't used it much.

[Willabe]

Oh, just a thought but for those that start new threads on this project it would be cool to link them to this one for ease of finding I guess.

Sure, that would be good.


               Brad