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Hoffman Amps Forum image Author Topic: STINGER BY DENIS CORNELL - ROMANY PLUS  (Read 8412 times)

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Offline TIMBO

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STINGER BY DENIS CORNELL - ROMANY PLUS
« on: December 09, 2017, 02:50:44 am »
Hi guys, This is a scratch build I started a very long time ago.
http://www.guitargear.net.au/discussion/index.php?topic=47812.0
I have added a one tube 6BM8 one tube reverb.
I have finally completed this project and thought all was done, took it to a gearfest and got heaps of feedback.
Removed the 6BM8 and found this to be the problem.
Tried a few more valves and problem persisted.
After some mods, this is the circuit now.

Voltages-
pin2 - 15.8v
pin6 - 208v
pin7 - 208v
pin8 - 1.29v
pin9 - 131v
 :dontknow:

 

Offline PRR

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Re: STINGER BY DENIS CORNELL - ROMANY PLUS
« Reply #1 on: December 09, 2017, 10:48:48 am »
Increase the 100K from * to #. A lot.

Note that Fender sometimes used 3,300K (3Meg) here, not 100k; which means adding another gain stage.

Resistors go both ways. This "dry" resistor also leaks-back wet signal INto the reverb path.

The Champ-class amp has just about enough gain stock, but adding a reverb path and mixer forces real compromise. Low dry gain, non-wild reverb strength, or extra gain.

Offline kagliostro

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Re: STINGER BY DENIS CORNELL - ROMANY PLUS
« Reply #2 on: December 09, 2017, 01:51:26 pm »
On VOX Cambridge the 3.3M resistor is bypassed with a cap



Franco
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Offline PRR

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Re: STINGER BY DENIS CORNELL - ROMANY PLUS
« Reply #3 on: December 09, 2017, 03:23:05 pm »
> On VOX Cambridge the 3.3M resistor is bypassed with a cap

Same on many Fenders. This network is just high-enough impedance it will lose treble, so we compensate.

AND the reverb driver is taken from the *second* stage. So much higher signal level, and we can take much more loss on the dry side of the reverb mixer. This loss works both ways: reverb return does not leak-back to reverb input as much.

Offline TIMBO

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Re: STINGER BY DENIS CORNELL - ROMANY PLUS
« Reply #4 on: December 09, 2017, 04:24:48 pm »
SO, It would be much better to insert the reverb off pin1 V1??

Offline PRR

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Re: STINGER BY DENIS CORNELL - ROMANY PLUS
« Reply #5 on: December 10, 2017, 12:23:43 am »
> better to insert the reverb off pin1 V1??

Then how are you going to bring the Return back in?

Offline TIMBO

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Re: STINGER BY DENIS CORNELL - ROMANY PLUS
« Reply #6 on: December 10, 2017, 12:30:07 am »
Hi PRR, This is how I have done it.


Works great, with lots of boing.
There is no signal loss or tone loss.

Offline sluckey

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Re: STINGER BY DENIS CORNELL - ROMANY PLUS
« Reply #7 on: December 10, 2017, 07:14:56 am »
The reverb level pot has dc voltage on it. Does it sound scratchy when you turn the knob?
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline kagliostro

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Re: STINGER BY DENIS CORNELL - ROMANY PLUS
« Reply #8 on: December 10, 2017, 08:53:59 am »
Quote
The reverb level pot has dc voltage on it.

and the .001 cap between * and 1Ma pot ?

Franco


Quote
EDIT:


I was looking on the wrong side of the 3.3M resistor  :BangHead: :BangHead: :BangHead:
« Last Edit: December 11, 2017, 08:06:02 am by kagliostro »
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Offline TIMBO

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Re: STINGER BY DENIS CORNELL - ROMANY PLUS
« Reply #9 on: December 10, 2017, 12:58:51 pm »
NO scratchy pot that I noticed.

Offline PRR

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Re: STINGER BY DENIS CORNELL - ROMANY PLUS
« Reply #10 on: December 11, 2017, 12:44:31 am »
The 0.02u cap could go on the other side of the 3.3Meg.

Offline TIMBO

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Re: STINGER BY DENIS CORNELL - ROMANY PLUS
« Reply #11 on: December 11, 2017, 02:09:37 am »
I'll give it ago. :thumbsup:

Offline TIMBO

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Re: STINGER BY DENIS CORNELL - ROMANY PLUS
« Reply #12 on: December 11, 2017, 03:42:35 am »
WORKS GREAT!!!!!!


PRR, was this insertion point your original thought?

 


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