[sclamb]

I don't hear any tube rush or humming.

PS Whey hey, 1000+ posts. Another of life's milestones successfully accomplished

 

[sclamb]

I just sent this to Jack:

"Whilst I accept what you have said about the compatibility of the WA6 SE maxxed design with the 274B tube (I had a really big flash and lots of sparks falling tonight), there are a number of people who have modified their own WA6 amps because they believe that the first capacitor is too high a value at 150uf, where Sophia Electric state that is should be no more than 4uf. I know that you use a choke (inductor) in the WA6 SE design, but again the thoughts being expressed to me are that if the choke is not at around 20 henrys then again it is not sufficient to stop the current in-rush to the tube, which causes the flashing and sparking.

Would you share with me the values of the first capacitor (I believe that it is a 150uf Blackgate) and the choke that you use in the WA6 SE with premium parts upgrade that I have? If I wanted the amp to be modified to have the first capacitor changed to 4uf (in line with Sophia's recommendation), would you be able to do that if I send the amp back to you for modification (unless you have any associates in the UK that you would be happy to undertake the modification). Am I right in assuming that the rest of the amp, and its ability to drive low or high impedance headphones, would not be affected?

Please don't take this as any criticism on my part of your knowledge or expertise. I just want to be able to use the Sophia Electric Princess 274B tube without the flashing or sparking, which must be shortening the tube life and performance, and the best way to achieve that would be to be in line with their recommendations."

Let's hope for a response with some detailed information.

 

[takezo]

Quote:

Originally Posted by sclamb /img/forum/go_quote.gif The sparks and flash are immediate. Why do you ask? If I then turn the amp off, wait 10 seconds and turn it on again then I rarely if ever see the flash or sparks.

does it accompany any kind of noise thru the headphone?
i ask because jack told me many months ago that the SE and the wa5-LEhas a
soft start of approx. 8-10 sec.... i'm fairly certain he wrote that... i wish i hadn't
trashed all of my old emails. i'm not sure what this means or if it's relevant in
any way... just brain storming i guess.

 

[sclamb]

I sometimes hear (or think I hear) what sounds like electrical plates charging (if you see what I mean). Maybe described as a clicking/charging sound for a second or two and then silence. I sometimes hear it at switch off too.

 

[takezo]

Quote:

Originally Posted by sclamb /img/forum/go_quote.gif I sometimes hear (or think I hear) what sounds like electrical plates charging (if you see what I mean). Maybe described as a clicking/charging sound for a second or two and then silence. I sometimes hear it at switch off too.

that's probably the tube "rush" i mentioned above... all rectifiers make this initial
plate charging sound... it is never violently loud though...
what i was looking for was an uncomfortable loud popping sound associated
with arcing...

 

[sclamb]

I definitely don't hear uncomfortable or loud popping sounds, and I have to listen very hard to hear the plate charging sound. That said, I have not had the phones on the last few times I have started the amp, so I will try that next time I switch on.

 

[sclamb]

I decided to buy another Princess 274B tube which arrived today. I put it into the WA6 SE and switched on. No flash and no spark. The mesh plates just gradually turned orange with no white light first.

I will monitor this over the next few days, as I did not notice the first tube flash or spark at the beginning, and see if the new tube stays fine or starts flashing/sparking. If it does, I will be sending both tubes and the amp to Jack for either a full refund (including the new tube as he has stated the amp is compatible) or a replacement of the tubes and a modification to the amp to make it compatible.

Anyway, fingers crossed this new tube stays fine which may point to a duff first tube.

 

[takezo]

you know, i wouldn't rule out the fact that most soviet and chinese
made tubes have short lives... but good luck.

 

[sclamb]

Well, the first tube only had about 60 hours on it, so hopefully not that short-lived!

 

[takezo]

Quote:

Originally Posted by sclamb /img/forum/go_quote.gif Well, the first tube only had about 60 hours on it, so hopefully not that short-lived!

oh, did it die? how did it die? no more sound? or SQ became bad?

 

[sclamb]

No. It was the tube that was flashing/sparking on start-up. It still sounds fine, but I wanted to try another tube to see if perhaps the first one was faulty. The new Sophia did not flash/spark on the three times I have turned on the amp. I am hoping it does start flashing or sparking and that perhaps the first tube had a problem.

 

[takezo]

well... if the caps in the amp were still charged then it wouldn't
stress the rectifier as much as if they were drained... turning the
amp on and off within hours will not drain the cap entirely, not as
completely as if you turn it on 24hrs. later...

*the wa6 has caps that should drain in minutes... not hours...
sorry for the misinformation.

i wouldn't place too much emphasis on the sparks as much as
sound degradation and odd mechanical sounds from the tube itself...
but then again, i have a chinese gz30 tube that sounds very
good but pings and makes mechanical noises frequently on turn on
and turn off... got it over a year ago; it hasn't sparked nor died yet...

 

[sclamb]

Don't forget that I have the Blackgates in the maxxed version, so not sure if that makes a difference to the draining time. That said, the amp had been off for about 40 hours when I switched it on with the new 274B, so the caps should have drained. I shall see how it goes over the next few days. If the flashing and sparking do not happen with this tube then I shall send the one that Jack supplied back to him and ask for a replacement.

 

[takezo]

i may be wrong, and have been many times, but i think you should just
keep using the previous princess and see if anything happens to
the sound... and try getting a tube tester to check and see if the
rectifier is getting low on emissions unusually fast... for all we know
the vast majority of these princesses have sparking issues regardless
of amp being used and still not affect the sound quality

 

[jamato8]

No sparks are normal unless it is the forth of July in the US, new years in China and other celebrations but not in tubes, no way, no how.