Search found 9626 matches

by Paul Barker
Wed Feb 12, 2025 12:36 pm
Forum: Everyones Projects
Topic: A not simple GM70 SE but not monoblock.
Replies: 1
Views: 127

Re: A not simple GM70 SE but not monoblock.

Image

The 38 watts is class A1 but small amount of grid current as it approaches zero volts is expected. So a driver with low output impedance is for that reason.
by Paul Barker
Wed Feb 12, 2025 12:19 pm
Forum: Everyones Projects
Topic: A not simple GM70 SE but not monoblock.
Replies: 1
Views: 127

A not simple GM70 SE but not monoblock.

The chassis I was planning to make a 300b amp is changing. It should house instead a stereo driver chassis for a dc coupled GM70 stereo chassis.

The power supply for the driver should fit in its signal section chassis . As such this chassis could have flexibility to drive a 211, 212, 833a.

I ...
by Paul Barker
Tue Feb 11, 2025 12:31 pm
Forum: News
Topic: Welcome back WD(WAD) Forum
Replies: 26
Views: 5220

Re: Welcome back WD(WAD) Forum

Mine was accepted soon enough since its not an emergency it takes what it takes but it comes.
by Paul Barker
Sun Feb 09, 2025 7:03 pm
Forum: Buying and Selling
Topic: Any Brompton fans?
Replies: 8
Views: 8925

Re: Any Brompton fans?

Since you came back I’ll update you on this thread. A friend passed away and left me his Brompton in his will. So I have two now. But I had a stroke and just walk or go on buses or trains. I’m ok walking but not confident to ride a bike. Not allowed to drive yet because I still have symptoms. If ...
by Paul Barker
Sun Feb 09, 2025 3:25 pm
Forum: News
Topic: Welcome back WD(WAD) Forum
Replies: 26
Views: 5220

Re: Welcome back WD(WAD) Forum

Thanks though Nick.
by Paul Barker
Sat Feb 08, 2025 7:01 am
Forum: Everyones Projects
Topic: 6V6 Single Valve Headphone Amp
Replies: 24
Views: 9229

Re: 6V6 Single Valve Headphone Amp

Certainly the fatter el38’s wouldnt fit youre chassis. But out of all the higher powered higher transconductace beam tubes and pentodes I like the quite different el38 and genuine Mullard much more affordable, especially the pl38 @ £25 delivered from Langrex. Also falling off a log.

Poundstertcher ...
by Paul Barker
Sat Feb 08, 2025 6:53 am
Forum: Everyones Projects
Topic: 6V6 Single Valve Headphone Amp
Replies: 24
Views: 9229

Re: 6V6 Single Valve Headphone Amp

I had to look at the MO data for the kt77, because Ive never encountered it. Derek Rocco is selling JJ’s for £28 at todays prices buying them is like falling off a log.

What surprised me was the better distortion profile in class ab ul pp fixed bias compared to cathode bias.

Only one chart on ...
by Paul Barker
Fri Feb 07, 2025 11:44 am
Forum: Everyones Projects
Topic: 6V6 Single Valve Headphone Amp
Replies: 24
Views: 9229

Re: 6V6 Single Valve Headphone Amp

If you have room for two free el34’s I’d try those.

The triode ri is 910 ohm which is the biggest draw compared to the EL84 in youre situation. S triode is also high at 11.5 mA/v when youre looking for a cathode driver.

I dont have a working valve tester but I could plug them into my el38 amp to ...
by Paul Barker
Fri Feb 07, 2025 11:39 am
Forum: Everyones Projects
Topic: 6V6 Single Valve Headphone Amp
Replies: 24
Views: 9229

Re: 6V6 Single Valve Headphone Amp

I’ll clean up the inductance matter:

EL34 triode mu is 11. I can send two for nowt

Obviously el84 is mu 19. But 5k se might be ok, pp requires 10k. But 5k se isnt the usual 3 to one impedance ratio so might be a compromise on what you could hear with more load impedance and the associated ...
by Paul Barker
Fri Feb 07, 2025 11:31 am
Forum: Assorted Stuff
Topic: Nothing In Particular
Replies: 16990
Views: 8107066

Re: Nothing In Particular


I loved metalwork at school.

I got an O level GCE in the subject, but I can't remember what the test piece was, I think brazing was involved.

My first job, at Marconi, involved workshop training, for which I an eternally grateful. T'was there I increased my basic skills and added gas (oxy ...
by Paul Barker
Fri Feb 07, 2025 11:23 am
Forum: Jokes
Topic: Jokes
Replies: 253
Views: 231240

Re: Jokes

Image
by Paul Barker
Fri Feb 07, 2025 7:48 am
Forum: Your Fave Artists
Topic: New Led Zeppelin film alert
Replies: 8
Views: 8539

Re: New Led Zeppelin film alert

There is already a youtube from the Yard Birds to Led Zepelin.



Originally named The New Yardbirds.
by Paul Barker
Fri Feb 07, 2025 6:50 am
Forum: Everyones Projects
Topic: 6V6 Single Valve Headphone Amp
Replies: 24
Views: 9229

Re: 6V6 Single Valve Headphone Amp

EL34 triode mu is 11. I can send two for nowt

Obviously el84 is mu 19. But 5k se might be ok, pp requires 10k.
by Paul Barker
Fri Feb 07, 2025 6:15 am
Forum: Everyones Projects
Topic: 6V6 Single Valve Headphone Amp
Replies: 24
Views: 9229

Re: 6V6 Single Valve Headphone Amp

Big brother of 6V6; 6L6 has a mu of 8 likes a 5k load too? Isnt that enough. Also as a speaker driver 1.4 watts. Sounds pathetic but better than 6V6.

EL37 close to 6L6 has better mu of 9. BUT because its stated purpose suggestion by Mullard is as a push pull driver for a bigger output stage. So its ...
by Paul Barker
Thu Feb 06, 2025 10:32 am
Forum: Everyones Projects
Topic: 6V6 Single Valve Headphone Amp
Replies: 24
Views: 9229

Re: 6V6 Single Valve Headphone Amp

I know that Im a adhd pain in your’ backside.