From: maschuckert@gmail.com   
      
   On Wednesday, August 5, 2015 at 5:26:31 PM UTC-4, ad4k...@msn.com wrote:   
   > On Sunday, January 12, 2014 at 1:52:54 PM UTC-6, hugeshows wrote:   
   > > Hello all,   
   > >    
   > > One of my favorite tube amps has to be the Sherwood S-5000.  It's a little   
   gem of an integrated amp that is quite easily underestimated.  Most people   
   would put it in the same class as a Scott 299, also a 6BQ5 amp, although the   
   Sherwood is really a    
   7189 amp, and actually uses the higher plate voltage possible with the 7189.    
   It also has larger output transformers, and manages to put out 24w RMS per   
   channel.   
   > >    
   > > The pre-amp section, despite having dated ideas about tone control and   
   Fletcher-Munson curves (thankfully switchable) maintains a very neutral and   
   open sound.  The bass and treble knobs are actually usable and helpful at   
   times, and don't have some    
   insane Q that belies their center frequency.   The phono section is   
   startlingly good so long as the original Telefunken 12AX7s are occupying the   
   two sockets in the phono section.  There are a handful of other tubes that can   
   work there as well, but    
   filament hum and microphonics plague any U.S. made 12AX7 or 7025 I have ever   
   tried in this amp, shield or no.   
   > >    
   > > The use of 7199 tubes as the phase splitter/driver tubes is somewhat   
   unfortunate since they are hard to obtain these days.  The upshot is that they   
   seem to last a very long time in this circuit, and they sound quite good.    
   Some have attempted to use    
   6GH8A in this position, or modern Russian 7199 that are actually re-pinned   
   6GH8A, and I would strongly discourage that.  They don't sound right at all.    
   Just ask the ST-70 crowd.  You'd have to modify the circuit, and I think that   
   in this case, that's    
   just daft.  The 7199 last too long and sound too good to make that a useful   
   mod, IMHO.   
   > >    
   > > In this thread, I will be going over the basic steps of reviving a   
   Sherwood S-5000 as I rebuild yet another one of these beauties.  This is more   
   or less your standard re-cap job, plus replacing the selenium rectifier in the   
   bias supply.  There are    
   however some things that are specific to this amp, little tricks for dealing   
   with the tight chassis space, and other stuff too.  The way capacitors are   
   mounted in this amp is a real pain.  It uses twist-lock can caps, one of which   
   is mounted at a 35    
   degree angle.   
   > >    
   > > If -YOU- have an S-5000 or S-4400 and you have any questions about it,   
   please feel free to ask away and I will cover the topic in this thread.  I've   
   dealt with just about everything there is do deal with on these amps, as this   
   will be the 6th one I'   
   ve restored.  The S-5000II is a totally different beast using 7591s, and I   
   will not be covering that amp here.   
   > >    
   > > Still trying to figure out where I will post pics and schematics so I can   
   post links here, so give me a little while on that.   
   > >    
   > > For those of you exclusively into DIY, the S-5000 circuit is a very cool   
   and sweet sounding 7189 amp.  It's the only amp I've seen that gets 24 watts   
   out of a pair of 7189s.  I've made one using the Triode Electronics ST-70   
   board as a front-end and    
   the result was so good that it sold for $1000 despite being a prototype and   
   not terribly well built.  It was in a Hammond box as I recall, but I did   
   engine turn the top at least.  So we can also discuss DIY around this circuit   
   in this thread if anyone    
   wants.   
   > >    
   > > This is my favorite vintage amp of all time, so I can talk about it   
   endlessly without getting bored.   
   > >    
   > > Feel free to ask away as I prepare some pics and schematics to get this   
   started.   
   > >    
   > >    
   > > -forkinthesocket   
   >    
   > Yea, I did miss a few details, I guess.  I wanted to see if I could work the   
   system before I dove in.   
   > I had read several posts about how good the Sherwood S-5000 is so I bought   
   my own.  Nice cosmetic condition but a blown PWR transformer.  Primary side.   
   >    
   > Main problem with getting a non-stock replacement is the tight fit and the   
   30VDC filament and bias voltage needed.   
   > The numbers on the transformer are B922J3-5 and A949005.   
   > If I can't find an original replacement, I will have to look at the   
   rewinding option.  Seem that would be a bit costly.  I'm in no hurry, so I   
   will wait a while.   
      
   You can check out these guys-   
      
   http://www.heyboertransformers.com/tubeamps.shtml   
      
   They made a custom power transformer for my LK72 Scott several years ago at a   
   very reasonable price. They may know what specs you need already or you'll   
   have to draw up a spec.    
      
   BR's,   
      
   Mark   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)