Single Ended Amp with Reverb?

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eddiejg
Senior tube assistant
Posts: 166
(12/3/03 10:36 pm)
 Single Ended Amp with Reverb?
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 I have a guy wants me to build a single-ended 6L6- more or less a 5F2A.
But, he wants reverb.
I looked around the web, but can't find a schematic for such an animal.
While I scan my Torres book, anyone else out there been there, done that?
Any pitfalls to watch out for?
Thanks.
-Ed
 
bnwitt
Senior tube assistant
Posts: 146
(12/3/03 10:57 pm)
 Re: Single Ended Amp with Reverb?
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 Ed,
build him a revibe too!
 
eddiejg
Senior tube assistant
Posts: 167
(12/3/03 11:10 pm)
 Re: Single Ended Amp with Reverb?
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 That's on my list of things I have to/want to build, but not for this one.
Although, looking at it, I wonder if it could be adapted to be a reloop instead of a revibe?
Anyway, anyone with experience with the SE with reverb?
Torres book says reverb can be added to ANY amp.
-Ed
 
bluesbear
Hey get your own solder
Posts: 283
(12/4/03 12:23 am)
 Re: Single Ended Amp with Reverb?
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 I suggest that you look at the Princeton Reverb, aa1164 circuit for inspiration. It looks to me like you could add reverb to just about any amp using that design. I may try it on the tweed Champ clone I'm building......just for fun!
Tell us how you work it out.
Good luck!
Dave
 
Wanabejimi
Junior tube assistant
Posts: 26
(12/4/03 9:10 am)
 Re: Single Ended Amp with Reverb?
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 Click on the "Hi Octane Ultra" with brutal gain and reverb. This is basically a jcm 800 preamp into a single ended el84 amp. Would give you some ideas of adding reverb into a s.e. amp

www.ax84.com/hioctane.html
 
eddiejg
Senior tube assistant
Posts: 168
(12/4/03 10:31 am)
 Re: Single Ended Amp with Reverb?
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 Thanks, guys.
So, I'd mix the reverb into the input of the driver section of the preamp tube.
And I need another OT just for the reverb.
And I'd need A 12AT7 & Another 1/2 12AX7.
I might as well add another 12AX7, switch to 2 6V6's instead of 1 6L6 & make the Princetone Reverb with tremolo too.
But, if I stick with my original plan of SE 6L6, can anyone recommend a particular reverb unit that would probably work best with a low power amp like this?
Or what is the original unit used for the PR?
Also, any suggestion for the extra 1/2 12AX7 I'd have?
Not that I want to complicate the design any more, but I hate to waste resources!
Thanks.
-Ed
 
bluesbear
Hey get your own solder
Posts: 284
(12/4/03 10:59 am)
 Re: Single Ended Amp with Reverb?
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 For tremolo, take another look at the aa1164 schematic. Simple, few parts, only uses 1/2 a tube and sounds sweet. I'm not certain how to tie this in on a single ended amp, though. I'd like to try it, too, If anyone could tell us how.
That ought to be a sweet amp when you're done.
Dave

Edited by: bluesbear at: 12/4/03 11:03 am
 
eddiejg
Senior tube assistant
Posts: 169
(12/4/03 11:19 am)
 Re: Single Ended Amp with Reverb?
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 I wouldn't add trem to the SE, I'd only include that if I abandoned the SE for the PR completely.
I'm curious if trem would work on an SE, though.
Without thinking about it too much, I'd say that it won't work, but I'll probably be wrong.
Anyway, more advice & suggestions for the SE with reverb will be much appreciated.
-Ed
 
bluesbear
Hey get your own solder
Posts: 285
(12/5/03 1:14 am)
 Re: Single Ended Amp with Reverb?
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 The Vibrochamp says that tremolo will work on a single ended amp but that circuit uses a full tube while you only have 1/2 tube to spare. The Princeton trem circuit only uses 1/2 tube....but I don't really know how or where to tie it in, especially with cathode bias. If anyone knows how, let us know. I'm starting my Vibrochamp Reverb this weekend.
Dave
 
eddiejg
Senior tube assistant
Posts: 173
(12/5/03 9:10 am)
 Re: Single Ended Amp with Reverb?
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 Dave-
You're building a Vibrochamp with reverb?
Can you give me some details?
What reverb circuit are you using?
What reverb tank?
Do you have a complete schematic?
Thanks for any info you can share.
-Ed
 
Tiny Daddy
I will work on all amps
Posts: 343
(12/5/03 9:12 am)
 Re: Single Ended Amp with Reverb?
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 Ampeg (sorry no schematic) used voltage-doublers on either side of the center-tapped filament winding to get +/- voltages for a dual op-amp reverb driver and recovery circuit. All this in a 50-watt tube amp. I assume they used reverb circuitry similar to Fender Blues Deluxe.
 
bluesbear
Hey get your own solder
Posts: 288
(12/10/03 11:55 am)
 Re: Single Ended Amp with Reverb?
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 "You're building a Vibrochamp with reverb?"
As soon as I can figure out what I need.

"Can you give me some details?"
Not much to tell...just a Vibrohamp with reverb added.

"What reverb circuit are you using?"
I need work out a tremolo and reverb circuit that uses 2 tubes. The Vibrochamp circuit with a Fender style reverb would need 2 1/2 tubes. I either need a reverb circuit that only uses 2 halves or a 1/2 tube tremolo circuit that will work on the Champ.

"What reverb tank?"
Probably the same as a Princeton Reverb (small).

"Do you have a complete schematic?"
No, I figure it out as I go. Then, when I get everything together and working, I draw a schematic.

If anyone has any ideas on a tremolo and reverb circuit that uses 2 tubes, please let us know.

Thanks!!!!!

Dave
 
eddiejg
Senior tube assistant
Posts: 177
(12/10/03 1:04 pm)
 Single Ended Amp with Reverb?
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 Dave-
I found out a little more info on this.
In order to get it to work with the SE, you need an extra 12AX7 stage to mix the signal with the dry signal before it goes into the power tube.
If you look at the schematic wannabejimi linked above, they used that method there (it's way over on the right near the power tube).
So, I think you're looking at 3 tubes just for the reverb & trem.
It may be possible to do it with 2 tubes, but I can't find any schematics showing how to do it.
Unless someone can tell us how to use Doug's reverb tank # 4FB3D1B- capacitor driven.
Does this mean it doesn't require any tubes?
-Ed
 
eddiejg
Senior tube assistant
Posts: 178
(12/11/03 9:34 am)
 Single Ended Amp with Reverb?
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 OK.
A little more info:
www1.korksoft.com/~schem/...ocket2.pdf
This is an Ampeg with reverb & tremolo & uses 1 12AX7 to drive both.
I'm assuming this is the type of circuit that would use the 4FB3D1B unit that Doug sells.
However, since it's push-pull, you will probably have to use the extra stage (1/2 12AX7) to mix the reverb into the dry signal for SE (unless that 1/2 tube is already performing that duty).
Still, that's under your req for 2 tubes or less.
If my assumptions are correct.
For me, maybe reverb with just 1 12AX7 (1/2?)?
Any Ampeg experts with some additional knowledge/wisdom?
-Ed
 
Tiny Daddy
I will work on all amps
Posts: 352
(12/11/03 2:01 pm)
 Re: Single Ended Amp with Reverb?
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 I am thinking the Ampeg "echo unit" is digital, not a spring reverb.
 
eddiejg
Senior tube assistant
Posts: 179
(12/11/03 2:49 pm)
 Re: Single Ended Amp with Reverb?
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 Thanks.
If that's so, does anyone know of an example circuit that uses the 'capacitor driven' reverb tank that Doug carries?
Thanks.
-Ed
 
Tiny Daddy
I will work on all amps
Posts: 355
(12/11/03 4:16 pm)
 Re: Single Ended Amp with Reverb?
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 May I suggest a simple cathode follower using 12AU7 (12AX7 may work also) with plate to B+, 1M grid resistor, 3.3K in series with 47K cathode resistor, .022uF input coupling and 1uF output coupling. Connect the cathode to the 3.3K, then 47K to ground. The 1M goes from the grid to the junction of the 3.3K and 47K.
 
eddiejg
Senior tube assistant
Posts: 190
(1/9/04 1:34 pm)
 Re: Single Ended Amp with Reverb?
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 Dave-
How you coming along with this?
I'm almost ready to start building mine next week.
-Ed
 
Moosehead2
Junior tube assistant
Posts: 44
(3/15/04 9:25 am)
 Kevin O'connor
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 If you check out Kevin O'Connors's "generations of tone" he show tonnes of stuff you can do with a SE amp including reverb, tremolo, triode pentode switching etc.. Its all based on the champ. My favorite is the champ with a super lead preamp circuit...cool.
 
eddiejg
Senior tube assistant
Posts: 248
(3/15/04 10:39 am)
 Kevin O'connor