Reverb using two triodes

[tubeswell]

Carvin runs a single 12AX7 reverb circuit in all of their amps, and it works rather nice, if it is not quite Fenderish. No external reverb transformer needed either. I can send a schematic if it helps.

That sounds like another promising lead hasserl. The tubeswell@hotmail.com address should be able to handle attachments.

Cheers

[Tubenit]

12AX7 reverb

I have used one 12Ax7 for reverb on 12 different amps and like the sound of it. I have owned a Princeton Reverb and used it for comparison. I also don't do surf music and only dial my reverb to about 3-5 max. Using a PR, I dialed it to between 2-3. Frankly, I like this specific reverb design using one 12Ax7 better because it reverbs more mids. I am not saying it's better but simply that I prefer it.


So if you are using it sparingly, you might find this works for you? You'll need to download ExpressSCH to open these files (I have built all of these):

http://www.el34world.com/Forum/yabb2...num=1163435923
http://www.el34world.com/Forum/yabb2...num=1199629316
http://www.el34world.com/Forum/yabb2...num=1163456681
http://www.el34world.com/Forum/yabb2...num=1163457605

I might add that Gibson and some other companies made amps with one 12Ax7 driving the reverb such as the Gibson Scout.
http://www.el34world.com/charts/Sche...7RVT_SCOUT.pdf

[Bruce / Mission Amps]

I have used one 12Ax7 for reverb on 12 different amps and like the sound of it. I have owned a Princeton Reverb and used it for comparison. I also don't do surf music and only dial my reverb to about 3-5 max. Using a PR, I dialed it to between 2-3. Frankly, I like this specific reverb design using one 12Ax7 better because it reverbs more mids. I am not saying it's better but simply that I prefer it.

Even if you are using one 12AX7... one to drive the tank and one to recover the tiny <10mavc signal from the other side of the tank, .... for great reverb, I think you'll need three amplification stages.
6-10mvac of reverberation from the tank is usually less then the AC hum noise floor! One more triode after the tank running flat out with a gain of 40 is only going to net you 240mv to 400mv of signal to work with. Mix that with a dry signal and there isn't much reverb.
Not saying it can't be done of course but for really good, rich sounding reverb, there is still another triode or gain stage somewhere that works after the mix and usually it is not the phase inverter.
How do we hear the amp you referred to in the Hoffman piece?

[Tubenit]

12AX7 reverb

Bruce,

I easily acknowledge that you (and many others) have far more knowledge about amps and probably reverb than I do. I am strictly a hobbyist at best with very little knowledge of electronics. Perhaps what I am using would not satisfy others? I would also presume you have a better feel for what others are actually looking for in an amp than I do. In light of that, your advice and approach might be the better way.

I am not trying to talk anybody into trying this method. I am simply saying it suited my needs just fine.

I do know that the owners of the amps that I have built and sold have been very happy with it and dial their reverb between 3-5 similar to what I do. I have had other forum members build some of these amps that I provided schematics for and report liking the reverb. I have had many others who have a long history with Fender amps hear my amps in person and express thinking the reverb was nice. I know that some of the D'Lite builds take a similar approach and have heard those owners report liking the reverb.

Again it is not Dick Dale or even Ronnie Earl or Anson Funderburg. It is far more subtle than that and may not be what others like. I never turn the reverb beyond 5 on my amps because it is becomes more intense than I like. And as I mentioned I used my PR on 2-3.

I am happy to send soundclips of songs I have done with these amps to anyone who requests them and leaves me a email to send to. No problem. Like many recordings, I do add some delay to the mix. I don't have a way to post my soundclips currently.

For those who don't have ExpressSCH, here is a website with some of the schematics that I referred to. Maybe something from these schematics will explain why it works or shouldn't work.

http://s28.photobucket.com/albums/c216/tubenit/?sc=3

Someone who is a regular poster on this forum and is recognized for knowing about amps can try it out and post the results. That might provide the most reliable information and source.

Having said that, I have yet to have anyone tell me there wasn't enough reverb for them doing it this way. And I am simply trying to respond to what I understood the original question to be.

With respect, Tubenit

[Bruce / Mission Amps]

Bruce,

I easily acknowledge that you (and many others) have far more knowledge about amps and probably reverb than I do. I am strictly a hobbyist at best with very little knowledge of electronics. Perhaps what I am using would not satisfy others? I would also presume you have a better feel for what others are actually looking for in an amp than I do. In light of that, your advice and approach might be the better way.

I am not trying to talk anybody into trying this method. I am simply saying it suited my needs just fine.
...
With respect, Tubenit

That's OK too and absolutely nothing wrong with that.
I went over and got that program to see what you are doing and it looks good.
I am not big reverb fan myself but the biggest customer complaint I always hear from players who want solid reverb is that, if it doesn't sound like big, fat, blackface Fender reverb it isn't reverb! .
Actually there are four camps out there... weaker and or thinner reverb is just fine, stand alone Fender reverb is rock-a-billy awesome, black face Fender reverb is the KING of amp reverb and the last one, I don't need no stinkin' reverb!
What is funny is that the BF Fender reverb freaks never have their reverb up past about 2.5 to 3 and then turn it down further when playing live!

[tubeswell]

I am happy to send soundclips of songs I have done with these amps to anyone who requests them and leaves me a email to send to. No problem.

Hi Tubenit, nice collection of photos and schems. (I couldn't get a MacOSX version of ExpressSCH to download, so the photobucket site was great Thanks).

Can you send me a soundclip of one of your reverb amps with the 'verb on 2-3? I'm not a fan of too much reverb myself, but I like a little to make the music come alive.

Address is tubeswell@hotmail.com

Cheers

PS I know I am about to wander slightly off the topic, but (since when did that stop me?) anyhow I note that you made your chassis' the way I made my 5F2A one. I'm interested in how you coloured up the dash-board? I saw a site on home-anodising Aluminium.

http://astro.neutral.org/anodise.shtml

I may have to seek another thread on this on the cabinetry forum, but did you by any chance anodise it and colour it, or did you colour it some other way? :-)

[Tubenit]

reverb sound bit

Tubeswell,

I have sent you two tunes I have previously recorded with the amps I posted schematics of. The reverb is set at about 2.5-3 on them. Hopefully that will be helpful to you. If not, I would be happy this wkend to record something specific trying to just demonstrate the reverb.

I am a hobbyist on a budget. So on all my amp chassis (which I buy blank), I simply etch the front chassis panel with 120 grit orbital sanding and follow using 7 coats of automotive lacquer basecoat followed by around 5 coats of clear coat. I sand with 320 grit after the first 3-4 basecoats. I am simply using Duplicolor spray cans from an auto store. I then use some decal letters from a hobby shop that cost less then $2.

Automotive lacquer holds up well on my cars in 100+ temp, snow and ice etc...... so I thought it would hold up on my amps. It has worked for me just fine. It certainly isn't as durable as anondized or powder coating but I have had zero problems using this method.

As a side note, the cabinets and guitars on the photobucket are also homemade by me.

Best regards, Tubenit

[tubeswell]

Thanks for the clips Tubenit

Like the Plexi 'verb - very cool. Do you mind me asking what were the primary and secondary Z's on the reverb tranny and the pan? It's cheaper for me to get trannys made up locally than order them in from overseas. I just need some specs (if you please).

Cheers

[Tubenit]

R/T and pan

I just use Fender type "replacement" Reverb trannie and pan. 25k/8 and the pan has 2250 ohm output. I may have bought it from Hoffmanamps or WeberVST ....... I don't remember.

Glad you like the Plexi 25w reverb amp. It's got a nice tone to it, I think.

With respect, Tubenit

[d95err]

What is funny is that the BF Fender reverb freaks never have their reverb up past about 2.5 to 3 and then turn it down further when playing live!

Looking at some schematics, it seems that Fender for some obscure reason is using a linear pot for the reverb control. This would explain why you get insane amounts at very low knob settings. Using a log pot (like any other volume control) would seem to make more sense and give a more useful range.

[JoeK]

I was quite interested in seeing the schematic for verb with two triodes but the links have gone and the bucket account doesn't seem to have a revrb schematic. Any idea if this info is still around?

[tubeswell]

I was quite interested in seeing the schematic for verb with two triodes but the links have gone and the bucket account doesn't seem to have a revrb schematic. Any idea if this info is still around?

Go to the Hoffman forum or the Dumble forum and search for 1 tube reverb. Basically most of the schematics I have seen use a modified BF topology for the reverb circuit and 1 triode for the driver connected to a BF-style RT, and 1 for the recovery. You can use a 12DW7 with the AU7 side as the driver and the AX7 side as the recovery. It is not as lush as the BF style reverb.

An alternative mentioned earlier in this thread is a pentode/triode tube like a ECL82 or ECL86 with the pentode side loaded to a champ style OT (5k-8k primary Z) and pan, and the triode as the recovery. This should get you a pretty decent reverb

Or you can go the transformerless route (as described on Merlin's Valve Wizard site)

[Tubenit]

Adding 1-tube reverb

Try the link above. With respect, Tubenit

[JoeK]

Adding 1-tube reverb

Try the link above. With respect, Tubenit

Thanks I just finished reading that thread when you posted your reply, looks very interesting and I think even if I use a different triode count it will help me understand reverb a bit more. Cheers Joe. Tell you what happens tomorrow.

[diagrammatiks]

I just got done trying a couple of different cap coupled circuits and the one described by merlin on his site is really good.

the only problem is that you need at least 3 triodes.

the srpp is real nice driving a 600-800 ohm tank though.

maybe a 6ac10 for three stages?

could try piggy backing the recovery stage off of another stage as well.