Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Ed_Chambley on August 20, 2011, 08:38:20 am
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Anyone ever built an amp which is an AC 30, but driven by a 6v6 to shoot for the output of 22 watts of the deluxe? There are characteristics of both of these amps I really like. I prefer the AC 30, but you have to get the thing so loud to really get that vox sound. On the other hand A Deluxe Reverb sounds great at lower volume output and the reverb is more to my liking.
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It's called an AC15, with just a pair of EL84's.
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There is an editable AC-30 schematic and layout here:
http://www.el34world.com/Forum/index.php?topic=575.0 (http://www.el34world.com/Forum/index.php?topic=575.0)
Just eliminate two tubes, change the remaining two to 6V6. Use a 330R/10w resistor.
With respect, Tubenit
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It's called an AC15, with just a pair of EL84's.
The AC 15 sounds nothing like the old AC 30. I have had both. The new AC 15 sounds less like a Vox than the Egnater Tweaker does. While not a bad sounding amp, it certainly does not sound like what I think of as a Vox sound. Particle board, cheap speaker, PCB and reverb that is not dimensional at all. The new AC 30 is the same way. As always tho, preference is always personal and the sales of the new AC 15 are strong, but the used market in my area has become flooded with them. It is fairly easy to pick-up a AC 15 less than a year old for $300.
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There is an editable AC-30 schematic and layout here:
http://www.el34world.com/Forum/index.php?topic=575.0 (http://www.el34world.com/Forum/index.php?topic=575.0)
Just eliminate two tubes, change the remaining two to 6V6. Use a 330R/10w resistor.
With respect, Tubenit
Thanks, I'll check it out.
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There is an editable AC-30 schematic and layout here:
http://www.el34world.com/Forum/index.php?topic=575.0 (http://www.el34world.com/Forum/index.php?topic=575.0)
Just eliminate two tubes, change the remaining two to 6V6. Use a 330R/10w resistor.
With respect, Tubenit
Any way to open this type of file other than using a CAD program? I looked and cannot find a PDF version.
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It opens with ExpressSCH which is a FREE download. The SCH Library has 100's of editable schematics and layouts so it's a very useful program to have. http://www.expresspcb.com/expresspcbhtm/Free_schematic_software.htm (http://www.expresspcb.com/expresspcbhtm/Free_schematic_software.htm)
Given your criteria, this is what I would attempt IF I were going to build it. There is a layout there to that you can easily edit to match the schematic.
With respect, Tubenit
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It opens with ExpressSCH which is a FREE download. The SCH Library has 100's of editable schematics and layouts so it's a very useful program to have. http://www.expresspcb.com/expresspcbhtm/Free_schematic_software.htm (http://www.expresspcb.com/expresspcbhtm/Free_schematic_software.htm)
Given your criteria, this is what I would attempt IF I were going to build it. There is a layout there to that you can easily edit to match the schematic.
With respect, Tubenit
I use Mac Computers, I tried eagle, but wouldn't work. I will find something that will work. Thanks for the
info.
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> It opens with ExpressSCH
I thought these opened in JSchem ?
http://dhost.info/jschem/ (http://dhost.info/jschem/)
"Cross platform with near-native OS integration for Windows, Mac OS X, Linux and commercial Unixes"
Free. Written by a fellow forum-visitor.
Oh, I see in the notes: "JSchem can read ExpressSCH (.sch) files."
However ExpressPCB is Windows-only, Jschem is Java underneath so should work on nearly "any" platform (maybe a high-end smartphone? Ugh!).
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I lived in England in the early 70's and there was real VOX AC-30 where we jammed. I know nothing about contemporary versions. Man, that was a barnburner of an amp.
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Yes, for Mac you can use Jschem, it is ok, but I cannot get the undo function to work on Mac and rotating grouped items ends up with the component looking like tagliatelle! That is not a complaint, just an observation.
It has been very useful for quick & simple schematics and is free. More complex schematics begin to require professional CAD software.
A 6V6-AC15 type circuit is on my own to do list. To my mind the AC15 circuit is not simply "half an AC30". These circuits have been changing ever since the sixties, but you could very generally say that the AC15 has a small pentode preamp and the AC30 has a triode preamp. It depends on which year, which channel, etc. and you can really get many pointers from looking at all the variations of both, or even the AC10 too.
Best, tony
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Since the AC15 uses a EF86, I thought I'd throw this idea out which uses a 5879 pentode which reportedly is less microphonic. This is a version of DaGeezer's HoSo56 which is a great amp!
Using this idea would allow an extra triode freed up to have a 12AT7 driving the reverb.
And it would give you essentially 3 different amps tones!
Just another thought. With respect, Tubenit
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It's called an AC15, with just a pair of EL84's.
The AC 15 sounds nothing like the old AC 30. I have had both. The new AC 15 sounds ...
Right. The modern amps sound like modern amps.
I meant, it the 60's, Vox also produced the AC15. And it sounds like a quieter AC30. There was also a version produced with a pair of 12" speakers, called the AC15 Twin. The only way to tell it's not an AC-30 (apart from volume) is to count the number of output tubes.
My point is only that if you want the same sound, but quieter, use a smaller output stage.
That, and that 6V6's don't sound like EL84's (especially under distortion). You'll want to pick one or the other, or know what you'll be getting.
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i have built an AC15 that has a pentode preamp (same component values but a 6AU6 instead of an EF86. it's probably wrong but its a cheaper tube and has a bit more gain. i like the sound) and a triode preamp. the triode preamp is the treble and normal preamp of an old AC30. no top boost.
i love this amp. the only thing i might add is something that does the exact opposite of the "cut" control. something that cuts bass instead of treble. the combination of these 2 and the 3 different preamp volumes makes a very versatile amp.
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It's called an AC15, with just a pair of EL84's.
The AC 15 sounds nothing like the old AC 30. I have had both. The new AC 15 sounds ...
Right. The modern amps sound like modern amps.
I meant, it the 60's, Vox also produced the AC15. And it sounds like a quieter AC30. There was also a version produced with a pair of 12" speakers, called the AC15 Twin. The only way to tell it's not an AC-30 (apart from volume) is to count the number of output tubes.
My point is only that if you want the same sound, but quieter, use a smaller output stage.
That, and that 6V6's don't sound like EL84's (especially under distortion). You'll want to pick one or the other, or know what you'll be getting.
OK, now I am following you. I did not know of the AC15 twin. I need to do a little research.
Thanks
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HotBluePlates knows his stuff and has been my amp building mentor. He is super knowledgeable about the vintage amps in particular.
There are numerous early AC15 models with schematics listed here under the VOX category.
http://www.el34world.com/charts/Schematics1.php (http://www.el34world.com/charts/Schematics1.php)
With respect, Tubenit
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I only know that stuff because there was a great vintage guitar shop outside of Nashville that had all the cool british amps.
There was a point in time where they might have 4 early-60's AC-30's, a few AC-15's, a pair of AC-50's... and of course, all the old Marshall, Selmer and Watkins (WEM) stuff.
So I've heard some of the cool british amps, when most vintage shops are lucky to have a few blackface Fender amps.
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HBP--
Mackie2 here:
i haven't been on here much in a while--Mike "E"'s Guitar is out of BIZ at the old location--He sold the Building and moved his operation to his farm--He still has an internet BIZ--has some cool old amps still!
My Avtar Amp with red cap is a TRI-AMP: Pwr PP 6SN7's, EL84's, and 6L6 or 6V6--All variable PWR except 6SN7--No solid-state reducing B+--
Later,
Send me an email: mackie2@comcast.net
Mackie2
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Now that is truly a shame!!
Everyone: If you like Brad Paisley's tone, perhaps the #1 reason he is playing Dr Z amps is because Mike E had them in his shop before anyone else caught on. I was there when Brad was trying them out, and bought his first Dr Z amp.
Anyway, that's a major loss for Nashville. I always felt Mike (and Jody) was a real class act. And he had all the stuff no one else in town had.
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Everyone: If you like Brad Paisley's tone, perhaps the #1 reason he is playing Dr Z amps is because Mike E had them in his shop before anyone else caught on. I was there when Brad was trying them out, and bought his first Dr Z amp.
Paisley uses z amps along with bruno, ac30's and has a trainwreck as well. I have tried many z amps and never found one I really like. Must be me cause many rave about them. There is a place here in North Georgia called Humbucker Music and they have an extensive website as well. They have tons of z amps. Cool thing about Humbucker is they actually stock what they have on their website. Sorry for the plug guys, I have no affiliation with them, it is just a really great place to visit to check out all those great amps in one place. They have Two Rock as well. Great sounding amps, but I really don't get the pricing. Waaaaaay to expensive for clone amps. I guess I am just an old fender amp guy. I like every fender amp made before CBS and I like a lot of the cbs's as well.
That is why I am looking into a vox/6v6. I am just finishing up on a JTM45 (i am preferring some mullard el34's over the kt66) and looking for my next adventure.