Stand Alone Reverb with bias vary Trem?

[Willabe]

What do you guys think? Can we do this? Has anyone here done this? Might sound really good.

Tore-T ReVibe is in parallel and a 6G16 Vibroverb is in series with the verb first, then the trem.

This would have the trem injected into the verb driver tube, so it would be in series?    

Sluckey said not long ago that bias vary trem works with cathode bias too.

Do I have it drawn right where/how the trem signal is injected?  Does the 220K grid return R go to ground and the trem signal is injected into the junction of the grid return R, grid stopper R and coupling cap?

Here's a drawing for a start;


                                    Brad        


 

[phsyconoodler]

Go look at a Vibrochamp.Do it that way.The vibrochamp wiggles the cathode of the preamp tube and it's a nice tremolo.I'm not sure how it would work with a reverb tank,it might open up a can of oscillation worms.

[HotBluePlates]

This would have the trem injected into the verb driver tube ...

Is the desired effect to have the reverb strength pulsate, like you were turning the reverb pot up and down?

[Willabe]

Is the desired effect to have the reverb strength pulsate, like you were turning the reverb pot up and down?

No, it's really a few ideas and phsyconoodler might have already hit the nail on the head. After all it is just a Champ, at least before the verb tank.    

I really love the sound of my 5G9's bias vary trem and I really love the sound of my SA verb unit.

So, I just thought it might be an easy thing to add the bias vary trem to a SA verb unit. Just 1 more tube and now you have trem and verb in the same box. Like the Tori-T ReVibe, but way less parts, space and a different sounding trem. But now that you point that possibility out, I was just re-reading today about trems in TUT 2 something that maybe sounds close to what your asking?

KOC says, "Usually the modulator is placed in the primary signal path..." Then, "But we can choose to modulate just the reverb signal, which can mimic echoes with even more realism." Which is where I came up with the idea.  Hmm....    

I had a BF SR that I giged with for a long time in the Chgo. blues clubs but never liked it's trem. I definitely would have been able to use the bias vary trem sound back then. I still have a BF PR and it's trem is like the SRs sound to me.

IIRC, Tubeswell said that part of why the bias vary trem sounds better is that it ends up running the output tubes a little warmer/hotter. What I do know is that I love the sound of it.

Sooo....

On 1 hand if I have a SA trem/verb then any new amps I build for myself would not need duplicate term/verb circuits. Less $$, less build time and less space in each build.

OTOH, if I go out to play (which I haven't done in a long time) it's 1 more thing to carry and will it sound as good as if the trem/verb were built in?

Only, way to find out. I guess I'm gonna have to build it, but how?      


                              Thanks,   Brad          
  

[jeff]

Is the desired effect to have the reverb strength pulsate, like you were turning the reverb pot up and down?
No,...

 I don't want to put words in HotBluePlates mouth, but I think he asked his question because it looks like you'd only be adding trem to the wet(reverb) signal. Your dry would be unaffected by the trem.

will it sound as good as if the trem/verb were built in?

It'll be a totally different animal

 The trem is before the input of the tank and not after the tank's output. So even if the trem was all the way up to the point where the volume shut off and on instead of just varing a little in volume, the springs would still be shaking. The sound of the shaking springs would be amplified by your main amp. So it'd be more like someone wiggling your dwell pot as you played. Could be a cool effect, but if you're after trem it's not gonna be the same sound.

I'm not sure about the circuit itself, but that's what I see as far as it's placement.

[sluckey]

If you have an AB763 amp you can easily see if you even want to do this. As for your circuit, here's how I would try to modulate the reverb driver tube...

[HotBluePlates]

I don't want to put words in HotBluePlates mouth, but I think he asked his question because it looks like you'd only be adding trem to the wet(reverb) signal. Your dry would be unaffected by the trem.

Pretty much right.

I guess I should've asked, "do you want to 'verb the wiggle, or wiggle the 'verb?"

As drawn, it wiggles the 'verb, which may not be what you'll want.

[jeff]

Will bias trem on a SE sound bad?

On a PP, because the two tubes are out of phase, the modulation frequency is cancled out.
On a SE won't you hear the oscillation? And since this is driving the tank you'd be shaking the springs weither or not you were playing.
I think that may result in unwanted reverb tank noise(???like setting your SA reverb unit on a washing machine???).

I'm not sure, but thought it'd be a good question.

[HotBluePlates]

On a SE won't you hear the oscillation? Even if it is too low to hear you'd be shaking the springs weither or not you were playing.

Tremolo rate is around 3-7Hz. Far too low to hear. Probably too low to overcome spring inertia with no other signal.

[Willabe]

I found these Garnet Gnome SE 6L6 cathode bias very trem. One has reverb the other doesn't.
Still thinking about all your replys.

http://www.el34world.com/charts/Schematics/files/garnet/garnet_g15tr_gnome.pdf            

http://www.el34world.com/charts/Schematics/files/garnet/garnet_g15t_gnome.pdf


            Thanks,        Brad    
                

[Willabe]

I don't want to put words in HotBluePlates mouth, but I think he asked his question because it looks like you'd only be adding trem to the wet(reverb) signal. Your dry would be unaffected by the trem.

So it'd be more like someone wiggling your dwell pot as you played. Could be a cool effect, but if you're after trem it's not gonna be the same sound.

I don't want to put words in HotBluePlates mouth, but I think he asked his question because it looks like you'd only be adding trem to the wet(reverb) signal. Your dry would be unaffected by the trem.

I guess I should've asked, "do you want to 'verb the wiggle, or wiggle the 'verb?"

I think you guys are right. I suffer from tunnel vision, completely forgot about the dry signal parallel to the wet signal.      

The KOC quote does not mention if the trem is pre or post to the verb.

I thought about this for a while and although this verson would not be power tube bias vary, this might work and sound good? It would now have trem on both the dry/wet signals.

What do you guys think?


                   Brad      

[sluckey]

You can't pick up the dry signal from the cathode of that first triode because of the 25uF bypass cap.

Your trem signal can never get thru the depth pot because of the grounded wiper. Look at the vibrochamp.

[Willabe]

Doh!    

How about this? Strike 2?

Hmmm.... Or, I could move the K bypass cap to V1b and re-work the FB loop to be like a Vibro Champ? Strike 3?


                     Brad      

I just noticed, if #3 works, I probably don't need both coupling caps, the .1 on V1a's K and the .047 on the dry/mix CF's grid.  

[jeff]

How's about roach trem(twin reverb) strapped across the output jack?

[Willabe]

How's about roach trem(twin reverb) strapped across the output jack?

Hi Jeff,

Hmmm....    

That might work.         While I don't like the sound of the roach style trem, I don't see why I couldn't use the old style trem instead?

Both dry/wet signals would have trem on them after the mix control, which is post verb. It would be going to the input grid of the amp you are feeding the verb/trem. Might have to cut the trem signal way down, but so what. Maybe change the depth pot to 1M or would that increase the trem signal? Would have to lift the depth pot ground with a switch when not using the trem. It would bleed off signal when not in use, same as a BF roach trem. 


                             Thanks,    Brad