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Restoring a Sherwood S-5000



 
 
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  #41  
Old September 11th 15, 05:13 AM posted to rec.audio.tubes
Big Bad Bob
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Posts: 361
Default PWR transformer for a Sherwood S-5000

On 08/02/15 11:33, so wittily quipped:
> 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

>
> New guy. Desperate for help.
> The post about restoring the Sherwood S-5000 caught my eye.
> I sure would like to do that, but....
> My poor amp has a blown power transformer.
> Any ideas on a replacement?
>


maybe search on Mouser's web site for a Hammond equivalent. They have a
*LOT* of tube transformers there, power supplies, output, impedence
matching, etc.. It's worth a shot. if you know the correct voltage,
amperage, physical size, etc. you might just get an equivalent that has
extra windings or whatever but still does the job.


Ads
  #42  
Old September 11th 15, 05:16 AM posted to rec.audio.tubes
Big Bad Bob
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Posts: 361
Default Restoring a Sherwood S-5000

On 08/07/15 16:29, MarkS so wittily quipped:
> On Wednesday, August 5, 2015 at 5:26:31 PM UTC-4, 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
>


interesting, I'll bookmark that too. Wish I'd known about that before
tossing old gear [because of bad transformers, thinking there was no
hope, but that was decades ago]


  #43  
Old October 31st 15, 11:40 PM posted to rec.audio.tubes
[email protected]
external usenet poster
 
Posts: 1
Default Restoring a Sherwood S-5000

Hi everyone,

My first post here. I've only briefly skimmed this thread but it sure looks to be a great resource for restoring the Sherwood S-5000. I've got one on the bench - the older version with the separate tube shields on the 12AX7s. I'm not getting any sound at all.

I've checked all the voltages on the schematic and found that V3 for both grids is way off. Should be -1V on one side and -1.5V on the other. I've got around 18v for each. I've checked all the resistors attached to V3 and they're OK. I haven't checked any caps, thought I'd seek advice before I start lifting leads.

My supply voltages all appear to be OK. There's 415v on the 7189 plates (using those Soviet EL84s), Bias is -16 but it still has the selenium rectifier and old caps. Someone changed out the 3-way power can but that's all that's been done. I've checked all the tubes and swapped out V3 with a known good one.

I'm still learning to troubleshoot tube gear and hoping to learn a good deal with this Sherwood. Any help would be really appreciated.

Regards,
Bruce

  #44  
Old December 14th 16, 09:09 PM posted to rec.audio.tubes
[email protected]
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Posts: 1
Default Restoring a Sherwood S-5000

I have an RCA S-5000 which looks very similar to your picture. Didn't open it up yet but is it the same?
  #45  
Old August 1st 20, 05:38 PM posted to rec.audio.tubes
[email protected]
external usenet poster
 
Posts: 1
Default Restoring a Sherwood S-5000

On Sunday, January 12, 2014 at 12:52:54 PM UTC-7, 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


Would you consider doing a restoration to my S 5000 ? Please call me at 406-461-8700
  #46  
Old August 2nd 20, 10:58 AM posted to rec.audio.tubes
[email protected]
external usenet poster
 
Posts: 2
Default Restoring a Sherwood S-5000

On Saturday, August 1, 2020 at 11:38:25 AM UTC-5, wrote:
> On Sunday, January 12, 2014 at 12:52:54 PM UTC-7, 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

> Would you consider doing a restoration to my S 5000 ? Please call me at 406-461-8700

 




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