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   rec.audio.tubes      Tube-based amplifiers... that go to 11      52,877 messages   

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   Message 52,166 of 52,877   
   themend@gmail.com to All   
   Restoring a Sherwood S-5000   
   12 Jan 14 11:52:54   
   
   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   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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