Valve heater voltage. - World-Designs-Forum

bob orbell · #1 29th March 2017, 05:47 PM

Hi all, a question if I can, today I found that my Pre power supply has a faulty regulator, and the Pre valve heaters have been running with 8.9 volts for just over a week, it all came to light today because it just did't sound right, harsh in the mid band, the regulator has been changed and the heater volts are back to 6.3, should I junk the two tubes E88CC gold pin Mullards, it sounds better, but there is still some harshness. BOB

John Caswell · #2 29th March 2017, 06:24 PM

Hi Bob,
As the valves have been overrun for over a week I would junk them. It has probably reduced their life to quite a degree.

John

bob orbell · #3 29th March 2017, 06:38 PM

Thank's John, I was afraid that would be the answer,

. BOB

Richard · #4 29th March 2017, 07:25 PM

They are quite expensive Bob so feel free to pop them in the post and I can test them for you.

They are indirectly heated so, as long as the filament didn't melt, they may just have used up a little extra of their life the past week. The tester will show up a weak valve (usually due to old age)

bob orbell · #5 29th March 2017, 08:29 PM

O dear, they both got chucked in the bin just after I replied to John, one still survives though, I have been looking for replacements, you are correct about the price,

, I can send the remaining one to you Richard if you PM me your address, as I don't keep any members address. Thank's. BOB

Richard · #6 30th March 2017, 08:22 AM

Morning Bob, address sent. It would be interesting to know how it tests but the postage for just one may not be worth it esp if it's u/s.

bob orbell · #7 30th March 2017, 08:54 AM

Thank's Richard, I will send it to you for test, if it's US, it should fit in your bin OK

, if it test's OK, I will reimburse you the postage, thank's again. BOB

John Caswell · #8 30th March 2017, 09:09 AM

Hi Bob,
PM me with address and I will stick a couple of them in the post. I hate to see a grown man cry

John

Greg. · #9 30th March 2017, 11:55 AM

That's very generous! He's a very nice man, you know

bob orbell · #10 30th March 2017, 12:28 PM

Quote:

Originally Posted by John Caswell

Hi Bob,
PM me with address and I will stick a couple of them in the post. I hate to see a grown man cry

John

Well, that is most generous John and a big thank you. The tears are welling in my eye's as I type. PM to follow. BOB