Comments on: Improving Green Board Reverb http://billmaudio.com/wp Small amps, big sound. Thu, 09 Sep 2010 12:00:31 -0400 hourly 1 http://wordpress.org/?v=3.0.1 By: bill http://billmaudio.com/wp/?page_id=34&cpage=1#comment-10660 bill Mon, 09 Aug 2010 13:51:39 +0000 http://billmaudio.com/wp/?page_id=34#comment-10660 The 330K resistor sends a slightly stronger signal to the reverb. No tone difference. The 330K resistor sends a slightly stronger signal to the reverb. No tone difference.

]]> By: Greg Mauser http://billmaudio.com/wp/?page_id=34&cpage=1#comment-10393 Greg Mauser Thu, 05 Aug 2010 20:19:38 +0000 http://billmaudio.com/wp/?page_id=34#comment-10393 Hi Bill, I didn't see the answer I was looking for in the previous posts. In the green board reverb mod, can you elaborate on the difference of the reverb sound when using the 330K instead of the 470K for R56? I'm asking because I put the Ruby tank in and it sounds REALLY good but my ears are not as finely tuned as yours and I have not tested at all levels yet. Thanks so much, Greg Hi Bill,
I didn’t see the answer I was looking for in the previous posts. In the green board reverb mod, can you elaborate on the difference of the reverb sound when using the 330K
instead of the 470K for R56? I’m asking because I put the Ruby tank in and it sounds REALLY good but my ears are not as finely tuned as yours and
I have not tested at all levels yet.

Thanks so much,
Greg

]]> By: Glenn Heller http://billmaudio.com/wp/?page_id=34&cpage=1#comment-7776 Glenn Heller Mon, 21 Jun 2010 04:19:49 +0000 http://billmaudio.com/wp/?page_id=34#comment-7776 Thanks Bill. I do love the re-routed 'pre-master' reverb path making the balance much better while I change settings between full master and low master. Perhaps a linear pot change will be next for the reverb. Thanks Bill. I do love the re-routed ‘pre-master’ reverb path making the balance much better while I change settings between full master and low master. Perhaps a linear pot change will be next for the reverb.

]]> By: bill http://billmaudio.com/wp/?page_id=34&cpage=1#comment-7576 bill Thu, 17 Jun 2010 23:51:01 +0000 http://billmaudio.com/wp/?page_id=34#comment-7576 I have not tried Dieter's mod. R43 on the green board is R37 on the cream board. Fender increased the value to 1MΩ. The difference is not really noticeable. I have not tried Dieter’s mod. R43 on the green board is R37 on the cream board. Fender increased the value to 1MΩ. The difference is not really noticeable.

]]> By: Glenn Heller http://billmaudio.com/wp/?page_id=34&cpage=1#comment-7444 Glenn Heller Wed, 16 Jun 2010 05:24:16 +0000 http://billmaudio.com/wp/?page_id=34#comment-7444 Hi Bill. After installing this reverb mod on my green board, I felt the reverb sounded more ditorted as i increased preamp overdrive (in a brittle way, not a true reflection). And still a bit noticable with pre amp down and main volume up. Upon reading the first comments by Dieter Billinger on 1/1/09 I'm wondering if you've also tried his resistor and cap mod to the reverb circuit? Upon looking for R43 on schematics it appears to say (910K) but is that a standard value? Am I looking at the wrong resistor? Can you help "clear this up"? Hi Bill. After installing this reverb mod on my green board, I felt the reverb sounded more ditorted as i increased preamp overdrive (in a brittle way, not a true reflection). And still a bit noticable with pre amp down and main volume up. Upon reading the first comments by Dieter Billinger on 1/1/09 I’m wondering if you’ve also tried his resistor and cap mod to the reverb circuit? Upon looking for R43 on schematics it appears to say (910K) but is that a standard value? Am I looking at the wrong resistor? Can you help “clear this up”?

]]> By: bill http://billmaudio.com/wp/?page_id=34&cpage=1#comment-5643 bill Thu, 29 Apr 2010 13:52:11 +0000 http://billmaudio.com/wp/?page_id=34#comment-5643 That tank is probably the wrong impedance for the BJr. Use the stock Accutronics 8EB2C1B tank or the replacement Ruby or MOD tank available from Mojo Musical or Antique Electronics. You can also see how to repair the usual problem with the tank here: <a href="http://billmaudio.com/wp/?page_id=46" rel="nofollow">http://billmaudio.com/wp/?page_id=46</a>. The red wire goes towards the middle of the amp. The black is under V1. If you're interested in improving the tone, start with the basic mods. Upgrading the transformer doesn't help much if the amp is strangled by the stock electronics. There's no magic about where you buy your tubes. A pair of JJ EL84s from Mojo, Tubestore, Antique Electronics, etc. are the same. Matched 12AX7s are a waste of money. That tank is probably the wrong impedance for the BJr. Use the stock Accutronics 8EB2C1B tank or the replacement Ruby or MOD tank available from Mojo Musical or Antique Electronics. You can also see how to repair the usual problem with the tank here: http://billmaudio.com/wp/?page_id=46.

The red wire goes towards the middle of the amp. The black is under V1.

If you’re interested in improving the tone, start with the basic mods. Upgrading the transformer doesn’t help much if the amp is strangled by the stock electronics. There’s no magic about where you buy your tubes. A pair of JJ EL84s from Mojo, Tubestore, Antique Electronics, etc. are the same. Matched 12AX7s are a waste of money.

]]> By: Ron Ditty (P-strat63) http://billmaudio.com/wp/?page_id=34&cpage=1#comment-5603 Ron Ditty (P-strat63) Wed, 28 Apr 2010 03:08:44 +0000 http://billmaudio.com/wp/?page_id=34#comment-5603 Hi Bill: The reverb on my creamboard FBJr died. After replacing it with another tank, I found the original to be the problem. The replacement is from a 1980's Musicman RP112-65 combo. The trouble is that now the reverb is very noisy. Unusably noisy. I don't use a lot of reverb to begin with, just enough to add 'life' to the sound. Is it possible that I put the wires on backwards (I don't want to swap them until I know that I won't damage a 'vintage' tank.), or is this tank bad also? Which tank would be a good replacement? Soon, I'll be ordering the stand-by switch and your new transformer. There's a guy on e-Bay selling matched tubes for the FBJr that I'm considering, either him or the Amp Doctor. Thanks for your help, Ron Hi Bill:

The reverb on my creamboard FBJr died. After replacing it with another tank, I found the original to be the problem. The replacement is from a 1980′s Musicman RP112-65 combo. The trouble is that now the reverb is very noisy. Unusably noisy. I don’t use a lot of reverb to begin with, just enough to add ‘life’ to the sound.

Is it possible that I put the wires on backwards (I don’t want to swap them until I know that I won’t damage a ‘vintage’ tank.), or is this tank bad also? Which tank would be a good replacement?

Soon, I’ll be ordering the stand-by switch and your new transformer. There’s a guy on e-Bay selling matched tubes for the FBJr that I’m considering, either him or the Amp Doctor.

Thanks for your help,

Ron

]]> By: Matthias Huth (Leipzig) http://billmaudio.com/wp/?page_id=34&cpage=1#comment-3684 Matthias Huth (Leipzig) Wed, 03 Feb 2010 22:13:40 +0000 http://billmaudio.com/wp/?page_id=34#comment-3684 Hi Bill, I've done the reverb kit in my '91 green board Blues Junior. I dont changed eitehr the capacitor nor the resistor. So the hum and noise is gone and all is in function. Only in case I turn the volume to 12 the reverb will missed a bit. May be if I would use a 330K resistor instead of the 470 K (R56) the result will be better. Thanks a lot. Matthias Hi Bill, I’ve done the reverb kit in my ’91 green board Blues Junior. I dont changed eitehr the capacitor nor the resistor. So the hum and noise is gone and all is in function. Only in case I turn the volume to 12 the reverb will missed a bit. May be if I would use a 330K resistor instead of the 470 K (R56) the result will be better. Thanks a lot. Matthias

]]> By: Dieter Billinger http://billmaudio.com/wp/?page_id=34&cpage=1#comment-2 Dieter Billinger Thu, 01 Jan 2009 23:31:48 +0000 http://billmaudio.com/wp/?page_id=34#comment-2 Reverb tone/distortion suggestion: I was thoroughly impressed by the improvements in my green board Woody Blues Junior, but I did find that the reverb was somewhat distorted either by signal overload or an excess of high frequencies causing harmonic distortions in the reverb springs. I found that turning the tone down on the guitar to reduce the highs had a dramatic effect on the cleanliness of the reverb. This lead me to believe that the problem was probably caused by excess highs in the reverb tank as opposed to general signal overload. It just happens to be that I didn’t have a 680K resistor on hand to replace R43 however I did have a 300K and a 390k on hand which I placed in series to get the needed value. (at least close enough for rock, country and blues). The junction point of these two resistors was an ideal spot to try and do some tone experimenting with the reverb. I pulled out my old capacitance substitution box and connected it between ground the resistor junction to see if a suitable capacitance will clean up the reverb distortion. Indeed this proved to be very worthwhile. I found that placing a 2.2 nf cap between the resistor junction and ground provided a remarkable clean up of the reverb signal without a substantial loss to the reverb signal. Reverb tone/distortion suggestion:
I was thoroughly impressed by the improvements in my green board Woody Blues Junior, but I did find that the reverb was somewhat distorted either by signal overload or an excess of high frequencies causing harmonic distortions in the reverb springs. I found that turning the tone down on the guitar to reduce the highs had a dramatic effect on the cleanliness of the reverb. This lead me to believe that the problem was probably caused by excess highs in the reverb tank as opposed to general signal overload. It just happens to be that I didn’t have a 680K resistor on hand to replace R43 however I did have a 300K and a 390k on hand which I placed in series to get the needed value. (at least close enough for rock, country and blues). The junction point of these two resistors was an ideal spot to try and do some tone experimenting with the reverb. I pulled out my old capacitance substitution box and connected it between ground the resistor junction to see if a suitable capacitance will clean up the reverb distortion. Indeed this proved to be very worthwhile. I found that placing a 2.2 nf cap between the resistor junction and ground provided a remarkable clean up of the reverb signal without a substantial loss to the reverb signal.

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