Rebirth of Studer C37

[Ki Choi]

Ki,
If your Studer C37 ever misses Europe, I offer to host it for a long stay. And it will be in good company with my two A80s and a few Revox's ... As I still have a few Swiss franc coins and bank notes around since my last visit to Switzerland, it will feel at home!
Congratulations!

The 85A2/CV449 and the E130L/7534 are easy to get in Europe , e.g. at Billigton Export UK

http://www.tube-and-valve-electronics.co.uk/default.asp

Great, I will check them for the tubes also.

Guess, if the C37 would visit you in Portugal, I wouldn't have to look for the European version of PS Audio P300 and send it along...

 

[flez007]

Very nice unit Ki, are you going to re-wire to use an external preamp or leave it as-is?, it does look cool! - and of course will check with my local valve providers for those weird models you might need.

 

[Fred]

Very nice looking deck. BTW, do you know what the production year is for that model? Just curious.

 

[microstrip]

(...) To answer Roger's question from the other thread regarding input power, the machine is an European version with 220VAC 50Hz. My solution is to use a PS Audio P300 power regenerator that will take 120VAC input and will output 220V 50hz. Only the P300s shipped to outside of US can output at 220VAC. Otherwise, I have a 1KVA step-up transformer that can take US version P300 with 120V 50Hz output and bring it up to 220V 50hz. It would have been ideal to have the US (or Taiwan/Korean) version C37, but I should be happy with what I have.

Thus, if our European WBF members can help me source a P300 from there, I would be much appreciated.

Ki,

Unhappily the 240V P300 is very difficult to get in Europe. But the 240V P300 is just a normal P300 with a step-up 115/230V transformer. I have owned one longtime ago and for some time used it to power some 110V 60 Hz equipment bypassing the output transformer.

BTW, you can build a 240V /50 Hz generator very easily with a low quality 500W power pro-amplifier, two 115/60V 300W power transformers with the 60V windings in parallel and the 115V ones in series, and an MP3 player playing continuously a 50Hz tome. Or just build one as described in P. Horowitz "The Art of Electronics".

BTW2, surely you know this link, but other members can be interesting page about rebuilding a C37.http://forum.studerundrevox.de/viewtopic.php?f=7&t=707&sid=d29984be50172849363d642f541bba1e

 

[mep]

Ki-I checked through my tube stash and I don't have either one of those tubes.

Mark

 

[Ki Choi]

Ki-I checked through my tube stash and I don't have either one of those tubes.

Mark

Hi Mark,

Thanks for checking.

I have a lead on a PS Audio P300 from Bulgaria...to power the C37 so that rebuild of the electronics can begin. Shipping would be a killer...

 

[jdza]

Ki

Watch out for the 230V P300. Of all the ones sold in this country only one is still running .The others all failed. The one still running powers only a turntable motor. It cannot deliver close to the 300W in the 230V guise. I honestly don't think it wil last with the 250VA the C37 consumes. You may be much better of with the P600.

BTW nothing against PS Audio. The current P10 made a huge difference in my system as did the PPP before it.

 

[microstrip]

Ki

Watch out for the 230V P300. Of all the ones sold in this country only one is still running .The others all failed. The one still running powers only a turntable motor. It cannot deliver close to the 300W in the 230V guise. I honestly don't think it wil last with the 250VA the C37 consumes. You may be much better of with the P600.

BTW nothing against PS Audio. The current P10 made a huge difference in my system as did the PPP before it.

Very true. Some P300 had fans (unhappily they were noisy), but some others did not have - only the place to fit them. At 200W load (~0.8A) it heated a lot - the only heat-sink is the outer box.

 

[Ki Choi]

Ki

Watch out for the 230V P300. Of all the ones sold in this country only one is still running .The others all failed. The one still running powers only a turntable motor. It cannot deliver close to the 300W in the 230V guise. I honestly don't think it wil last with the 250VA the C37 consumes. You may be much better of with the P600.

BTW nothing against PS Audio. The current P10 made a huge difference in my system as did the PPP before it.

Thanks for the info.

I will look for a P600 instead. In the meantime, I found a 1KVA step up trasnformer just to get it going even with wrong capstan speeds.

Ki

 

[Ki Choi]

Very nice looking deck. BTW, do you know what the production year is for that model? Just curious.

I believe the recorder was an earlier version before 1964. I'll have look into it further based on its serial number.

 

[garylkoh]

Ki

Watch out for the 230V P300. Of all the ones sold in this country only one is still running .The others all failed. The one still running powers only a turntable motor. It cannot deliver close to the 300W in the 230V guise. I honestly don't think it wil last with the 250VA the C37 consumes. You may be much better of with the P600.

I burned mine out burning CDs in Singapore. All it powered was a CD burner.

 

[Ki Choi]

I burned mine out burning CDs in Singapore. All it powered was a CD burner.

Umm... Thanks Gary for your additional comment. I will definately pass on the Bulgarian P300. It might be more practical for me to find a P600 locally for 50Hz and put the 1KVA setup transformer I have for 230VAC.

 

[garylkoh]

I can't imagine it being two completely different models for 115V and 230V. I've got a P600 here in the US - I will try taking it apart to see if it can be made to output 230V from 115V.

 

[Ki Choi]

I can't imagine it being two completely different models for 115V and 230V. I've got a P600 here in the US - I will try taking it apart to see if it can be made to output 230V from 115V.

Great, Gary. When I talked to PS Audio about converting a US model with 115V to 230V, they said they no longer had the "part" to do the work... It would interesting if they just added a step-up transformer at the output...

 

[jdza]

Great, Gary. When I talked to PS Audio about converting a US model with 115V to 230V, they said they no longer had the "part" to do the work... It would interesting if they just added a step-up transformer at the output...

I spoke to someone who had a broken P300 in his workshop. It does have a transformer on the output. He cannot remember what happens at the input though .

 

[Ki Choi]

I spoke to someone who had a broken P300 in his workshop. It does have a transformer on the output. He cannot remember what happens at the input though .

The input can be either 115V or 230V for both US and other models, as I understand it. Outputs are fixed for the specific region, according to PS Audio.

 

[garylkoh]

If the P600 uses output transformers it might be possible to just put a pair of transformers in side. There seems to be space.

There is a voltage switch, but all it does is to parallel/serial the transformer primaries as per normal practice.

View attachment 2461


The P600 has two amplifier modules and the outputs are switched through two Potter and Brumfield T90 relays to run two duplex outlets per module.

View attachment 2463


There seems to be space (and four available mounting holes) to mount a large transformer. Since there are two output modules, may be two transformers will be needed.


View attachment 2462

 

[Ki Choi]

Hi Gary:

Thanks for the photos and comments.

Is the 115/220 switch for input voltage selection?

If one can utilize full power from any one of the outlets on the back of the unit, then the two outputs from the output modules must be tied together (maybe at the outlets?).

Just looked up the manual for P600, and I can understand why people are blowing up these things with relatively small load... "P600 was capable of 720 watts of peak power and sustained levels of 300 to 400 watts." From my EE days many years ago, if I were to try to power any equipment with large enough input transformer as a load (or the European model models with a setup transformer of at least 1KVA size), its inductive load at initial power on would be very hard on P600 even with no load plugged into the unit for the European model with step sup transformer. P600 should have been rated at 300VA continuous duty. It reminds me of the amp spec war in the 70's with companies quoting peak power vs more realistic RMS power. So we now know the P300 probably was only good for 150VA at best...

 

[garylkoh]

Yes, the 115/230 switch is for input voltage selection. The four outlets are paralleled at the circuit board, so I am guessing that the two outputs from the output modules are tied to the outlets through those two relays.

 

[microstrip]

Great, Gary. When I talked to PS Audio about converting a US model with 115V to 230V, they said they no longer had the "part" to do the work... It would interesting if they just added a step-up transformer at the output...

Ki,

Most P300s had an internal switch to change between 115 and 230V input - I have bought one 115V from the USA using Audiogon. But only the 230/240v had the step up internal transformer - may be they are referring to it.