SRPP Tube-Driven Studio Spring Reverb

[Reo]

Hi all - have been lurking for a while, this is my first time posting.

I would like to build a spring reverb driver using the Valve Wizard's SRPP design:
http://www.valvewizard.co.uk/reverbdriver.html

I have looked at most of the other spring reverb threads on this forum (good info, thanks!) but I have a couple of questions about this circuit, specifically:

• What's the best way to implement a drive-level control?
• I'd like to use this circuit to drive Type 9 tanks, but I can only find them with input impedances that are either too low or too high....the circuit's designer recommends and input impedance between 100-300Ω but the only Type 9 tanks available are either 10Ω or 800Ω? Is there a way around this?
  
  I was thinking I might drive two Type 9 tanks in parallel....two 800Ω tanks in parallel would be 400Ω which doesn't seem overly-high?

Any help is greatly appreciated....I haven't done too many builds yet so this is definitely a learning process but I'm also looking to get it done in the next two weeks so I can start using it. I'll post pictures/info from the build in case anyone else is interested.

Thanks,

Reo

 

[joaquins]

800Ω should be good for that... higher inpedance won't harm the tube circuit, will have less power going to the tank but higher impedance tanks should have better sensitivity... so just look at the level, if it works for you it's ok!

I'd give it a try.

JS

 

[zebra50]

Hey this looks like a really nice project!

Do you have plans amplifier or buffer for the output of the reverb?

 

[ruffrecords]

Easiest way to add a drive control is to put a pot at the input to the SRPP.

I have a lot of time for the Valve Wizard but he is not always 100% correct. A 10V pp input will certainly make this circuit clip. Other than that it should work fine.

Ian

 

[Reo]

Thanks everyone, it helps a lot to have some other people look this over.

Easiest way to add a drive control is to put a pot at the input to the SRPP.

I have a lot of time for the Valve Wizard but he is not always 100% correct. A 10V pp input will certainly make this circuit clip. Other than that it should work fine.

Ian

Thanks - will do.

Hey this looks like a really nice project!

Do you have plans amplifier or buffer for the output of the reverb?

Yes, but they're still a little vague at the moment....

I'm going to use the driver to drive two tanks in parallel and then I was thinking of adapting a tube-based mic-preamp circuit to use as recovery amps, resulting in a stereo reverb.

I was thinking about using NYD's "One Bottle" design, as it looks pretty straightforward and should perform better than just having a single triode for each tank output.

Do you think the One Bottle could work well as a recovery amp?

I guess the input would have to be modified to accept the 2,575Ω output of the Type 9 tanks I plan to use.....I'll look around for a thread on how to do this.

Cheers,

Reo

 

[Reo]

If I use the NYD One Bottle for the recovery amp, would it be appropriate to feed the 2,575Ω output of the reverb tank straight into the grid of the first triode?

 

[PRR]

Yes.

 

[Reo]

Ok, thanks - hope to get the PSU section figured out by tomorrow and order the parts ;D

 

[thomasdf]

How did the build and testing go? I am interested in that SRPP design, what should I use as "receiver" gain stage, after the springs?

The belton springs I want to use (and already have) have a 10 ohms input impedance and 2575 ohms at the output.

I read on the site that the heaters would need 30V. Is this ok to feed the tubes such a high heater voltage? Won't they burn fast?

 

[PRR]

> I read on the site that the heaters would need 30V.

*Elevated* 30V. Not the same as heater supply.

> springs I want to use (and already have) have a 10 ohms input impedance

Use a transformer!! Tubes are high-impedance things. Merlin lists ways to slap a *medium* impedance spring with a tube. 10 Ohms is LOW impedance. Tube can't make adequate power in 10 Ohms without a transformer (or massive tubes).

 

[CJ]

reverb transformers are cheap,

heard some good solid state driven tanks at the guitar shop,

this is one case where it does not really matter which is used, tubes or solid state, as the springs will hide any sonic differences,

had an old Alamo amp in the other day, weird transistor supply voltage taken off the pwr tube cathode, had an S line tank that said "Assembled by beautiful girls in the state of Wisconsin"  on th sticker, had a  nasty feedback ring at about 1000 hz,

 

[thomasdf]

mmh.. Ok! I guess I'll stick to transistor for that stereo spring reverb I had in mind..!

Thanks for your input, I'll have a look at reverb transformers just for my personnal knowledge