25e5 output wattage?

Carbsandcaps

Carbsandcaps

Super Member
Just picked up a Sansui 1000 tube receiver (not 1000a). It uses 25e5 outputs and I was wondering if anyone has a ballpark estimate of output wattage? I don’t know much about this tube other than it uses a plate cap.

I already have plans to replace all the Suzuki and Elna caps. One of the voltage double caps is already leaking. IMG_3222.jpeg
 
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Carbsandcaps said:
Just picked up a Sansui 1000 tube receiver (not 1000a). It uses 25e5 outputs and I was wondering if anyone has a ballpark estimate of output wattage? I don’t know much about this tube other than it uses a plate cap.

I already have plans to replace all the Suzuki and Elna caps. One of the voltage double caps is already leaking. View attachment 3201304
Click to expand...
I have an early version 1000 and an SM-80 that use the 25E5 sweep tubes, there were at least two versions of the 1000, the early one has some similarities with the SM-80.
Yours may be the earlier 1000.
 
one thing I don't love about them though, the heaters are right across the mains using the 100v tap on the power transformer primary. If there is a heater-cathode short its going to be a bad time.
 
gadget73 said:
one thing I don't love about them though, the heaters are right across the mains using the 100v tap on the power transformer primary. If there is a heater-cathode short its going to be a bad time.
Click to expand...
Yes, this configuration really demands a 3-wire line cord for safety. Gotta say, I'm not fond of the germanium transistors in the phono pre either. Sorry, don't mean to run it down, and there are workarounds for all of this.

Jack
 
TriodeLuvr said:
That's probably a peak rating, not RMS. Outputs are sweep tubes rated for 10W anode dissipation. Continuous RMS output is likely to be closer to 15W or 18W.

Jack
Click to expand...

Some sweep tubes can handle a lot more power in audio service than the TV service ratings would indicate. I've always wanted a Sansui 1000, I think it's a very cool piece, and also interesting to have a tube amp from Sansui.
 
yep. the transformer primary has a bunch of taps. Its running off the 100v tap so its serving as an autotransformer if the input voltage doesn't happen to be 100v. Its an efficient way of doing it, its just the lack of isolation from the mains that I'm not in love with. If one of those output tubes develops a heater-cathode short you now have a hot chassis amplifier.

Grounded cord or an isolation transformer wouldn't be the dumbest thing to use here.
 
BTW, I have both the Sansui 1000 and the 1000A. The 1000A is restored and that went well. The 1000 is still a work in progress. "One Day..."
 
I got it all recapped and new bias pots installed but the output tubes and 6an8 preamps are testing very bad. It’s got output but not much. I found this damn Suzuki caps coupling the outputs leaking so bad that I couldn’t set the bias either the entire grid voltage was going to the plates of the pre amp tube or the preamp plate voltage was going to the outputs, either way they were red plating quick which I’m sure killed the outputs and probably the phase inverters. Replaced the caps and at least got my -29v for the bias. I’ll see how it sounds when the new tubes get here.

I see what you’re saying about the heater voltage off the mains. What a dumb idea! It will definitely be getting a 3 prong plug. image.jpg
 
Carbsandcaps said:
I got it all recapped and new bias pots installed but the output tubes and 6an8 preamps are testing very bad. It’s got output but not much. I found this damn Suzuki caps coupling the outputs leaking so bad that I couldn’t set the bias either the entire grid voltage was going to the plates of the pre amp tube or the preamp plate voltage was going to the outputs, either way they were red plating quick which I’m sure killed the outputs and probably the phase inverters. Replaced the caps and at least got my -29v for the bias. I’ll see how it sounds when the new tubes get here.

I see what you’re saying about the heater voltage off the mains. What a dumb idea! It will definitely be getting a 3 prong plug. View attachment 3203151
Click to expand...
You should replace the grey Suzuki caps, every single one.
 
25E5 (AKA PL36) was a common TV tube in Europe, never common in the US. 25BQ6 and 25DQ6 are probably decent subs, same pinout, though screen voltage would need to be lowered. I'd even consider rewiring for 25AV5 - no plate cap! But 25E5s aren't too expensive - little demand.
 
The grey Suzuki caps are well known for being leaky pieces of junk.


The EL36 (6v version of the PL36) sheets have audio amp operating conditions and say that an EL37 can replace them. I didn't study those two side by side but it really doesn't seem to be an awful tube. Ratings for the EL36 are much more audio-use like than what the 25E5 or PL36 sheet say though. Just a different application I suppose.
 
I've had issues with mechanical alignment between sections, usually its sloppy so one channel lags going up or going down, so it was possible to get it equal but it was a case of going slightly too high then tweaking it back down until it balanced.
 
So I filed out the center of one of the wipers so I got some adjustability to it but I’m wondering how close is close enough between the 2 pots? Ive got it pretty close but I don’t know what’s acceptable
 
Hi
I have a sansui SM-80, with sane output tubes as 1000 (25E5 or PL36). Can someone help me with bias setting? It's dificult to read PL36 datasheet for 330V plate voltage. I had set it to 40mA but I'm not shure if its too muche or too less.
Thanks
 
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