Following the court case between Michael Douglas, Catharine Zeta-Jones and "Hello" magazine, there is a new paparazzo scandal!
The shot below was snapped whilst EC8010 and 7N7 were carrying out testing on the Instock amplifier.
The builder is very upset and is considering a $1,000,000 law suit for distress and damage to reputation.
For those who have followed the story of the Instock, I have removed the grid stoppers on the 6528 entirely and so the D3As' cathodes are now truly directly-coupled to the ouptut valve.
The amplifier can now deliver 20W and sounds a touch crisper.
I'll post a revised drawing soon.
7N7
P.S. That paparazzo was EC8010!!
The shot below was snapped whilst EC8010 and 7N7 were carrying out testing on the Instock amplifier.
The builder is very upset and is considering a $1,000,000 law suit for distress and damage to reputation.
For those who have followed the story of the Instock, I have removed the grid stoppers on the 6528 entirely and so the D3As' cathodes are now truly directly-coupled to the ouptut valve.
The amplifier can now deliver 20W and sounds a touch crisper.
I'll post a revised drawing soon.
7N7
P.S. That paparazzo was EC8010!!Attachments
- I am delighted with the results - indeed as I was with a previous 6528 experiment.
Because I use them in my OTL designs and I don't need competition finding them.
If you know anyone who collects old audio magazines, Audio Update (the old Ike Eisenson magazine) had a cover picture of a 16 tube output stage using 6528s that Murray Zeligman and I built back in the late '70s. I still have the chassis for that amp- mono only, though, since we had a limited number of tubes.
If you know anyone who collects old audio magazines, Audio Update (the old Ike Eisenson magazine) had a cover picture of a 16 tube output stage using 6528s that Murray Zeligman and I built back in the late '70s. I still have the chassis for that amp- mono only, though, since we had a limited number of tubes.
Re: 6528 stock
I have about ten 6528s in all.
It was a type introduced to me by chance by Rod at Valve & Tube supplies; he sold me my first five, four of which were Tung-Sol Chatham ones.
However the best ones were the six Raytheons I got from Micronetix (which did have substantial stocks I think) and another pair of Cetrons I got on ebay.
Frank, as a line stage valve I do not think that 6528 is an easy choice; how are you going to deal with the colossal Miller capacitance? (Ca-g = 23.8pF - and we all know that we can read that as at least 40pF) and mu is 9.....
Hence the cathode followers!
7N7
I have about ten 6528s in all.
It was a type introduced to me by chance by Rod at Valve & Tube supplies; he sold me my first five, four of which were Tung-Sol Chatham ones.
However the best ones were the six Raytheons I got from Micronetix (which did have substantial stocks I think) and another pair of Cetrons I got on ebay.
Frank, as a line stage valve I do not think that 6528 is an easy choice; how are you going to deal with the colossal Miller capacitance? (Ca-g = 23.8pF - and we all know that we can read that as at least 40pF) and mu is 9.....
Hence the cathode followers!
7N7
6528.
Hi,
Ah....and the Chathams were probably 6528s NOT the A type?
Actually, both are very fine brands I love both of them.
Mr.Miller will be driven from a S&B CVT, that is... I'll try a balanced SEPP stage behind the CVT (with C37 woodoo knobs of course
).
Just an idea though....
BTW, I know a local dealer that has some Raytheon in stock...need to ask the price though.
FWIW,the 6528 was used in a Gates transmitter,the BHF-10 and the tube is still carried by Penta Labs, Bruckner and Richardson.
Prices vary from 10 to 100 USD...deep sigh.
If SY keeps on gobbling up the stock it is going to be 6080s though,
Hi,
Ah....and the Chathams were probably 6528s NOT the A type?
Actually, both are very fine brands I love both of them.
Mr.Miller will be driven from a S&B CVT, that is... I'll try a balanced SEPP stage behind the CVT (with C37 woodoo knobs of course
).Just an idea though....
BTW, I know a local dealer that has some Raytheon in stock...need to ask the price though.
FWIW,the 6528 was used in a Gates transmitter,the BHF-10 and the tube is still carried by Penta Labs, Bruckner and Richardson.
Prices vary from 10 to 100 USD...deep sigh.
If SY keeps on gobbling up the stock it is going to be 6080s though,
6528
Hi,
For what I had in mind...the mu of the 6528 would be handy.
Trying hard to talk me out of it,he?
Actually,there is likely a Russian tube that may come close...need to look it up.
6C41 perhaps.
Is any of you familiar with the TFK ED8000?
Marvellous curves and superb sounding thing.
Oh,while we're talking OTL...I read somewhere that a trioded EL509/6KG6 had an Ri of only 150 Ohm.
Has anyone checked this?
Cheers,
Hi,
For what I had in mind...the mu of the 6528 would be handy.
Trying hard to talk me out of it,he?
Actually,there is likely a Russian tube that may come close...need to look it up.
6C41 perhaps.
Is any of you familiar with the TFK ED8000?
Marvellous curves and superb sounding thing.
Oh,while we're talking OTL...I read somewhere that a trioded EL509/6KG6 had an Ri of only 150 Ohm.
Has anyone checked this?
Cheers,
6c41
6c41 is like a 6080 with both sections paralleled , better still the 6C33 . I'm very impressed with the sound of the 6c33 , keep the anode dissipation under 50 watts and they just last and last . One problem with these Russian triodes is that they're variable test-wise . Still pretty cheap , just buy more than you need and select
316a
6c41 is like a 6080 with both sections paralleled , better still the 6C33 . I'm very impressed with the sound of the 6c33 , keep the anode dissipation under 50 watts and they just last and last . One problem with these Russian triodes is that they're variable test-wise . Still pretty cheap , just buy more than you need and select
316a
Re: 6528
Well you should try triode-strapped 13E1.
This one has Pa of 95W, can pass half an amp and has ra as low as 130 ohms.
I use a couple in one of my amplifiers
7N7
fdegrove said:Hi,
For what I had in mind...the mu of the 6528 would be handy.
Trying hard to talk me out of it,he?
Actually,there is likely a Russian tube that may come close...need to look it up.
6C41 perhaps.
Is any of you familiar with the TFK ED8000?
Marvellous curves and superb sounding thing.
Oh,while we're talking OTL...I read somewhere that a trioded EL509/6KG6 had an Ri of only 150 Ohm.
Has anyone checked this?
Cheers,
Well you should try triode-strapped 13E1.
This one has Pa of 95W, can pass half an amp and has ra as low as 130 ohms.
I use a couple in one of my amplifiers
7N7
Attachments
Bas Horneman said:
Yes when I first saw one I had to have them. I started with S/H ones at £10 each.
Billingtion's amplifier uses a strange collection of valves. I have not heard it.
Mine at present is using just a 5965 or 13D3 depending on mood and a 7N7. With only 320V of HT I get a gnat's over 30W. The 13E1s are running at 150mA each, so they will probably last for years.
The STC type is different and perhpas even better looking than the Mazda example I showed; there is also an EEV version with black innards and gold pins, but I have not had much luck with them.
7N7
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