Search found 6957 matches

by Paul Barker
Wed Aug 21, 2019 1:52 pm
Forum: Speakers
Topic: Fane 12-250TC Retro Speaker.
Replies: 282
Views: 28481

Re: Fane 12-250TC Retro Speaker.

I vaguely remember the famous magazine article on OB by the man who invented Q57’s the resistance of baffle was key in the design
by Paul Barker
Tue Aug 13, 2019 9:59 am
Forum: Everyones Projects
Topic: The Other 13E1 SE-OTL
Replies: 130
Views: 9732

Re: The Other 13E1 SE-OTL

You’re vigilance at this stage has saved us all from a thread fault finding it later which may have taken some time to zero in on.
by Paul Barker
Fri Aug 02, 2019 8:57 pm
Forum: Everyones Projects
Topic: Inverted OTL with 6SN7/6AS7
Replies: 93
Views: 4463

Re: Inverted OTL with 6SN7/6AS7

Interesting
by Paul Barker
Sat Jul 27, 2019 3:58 pm
Forum: Assorted Stuff
Topic: The Audio-Talk Motorcycling thread.
Replies: 488
Views: 43027

Re: The Audio-Talk Motorcycling thread.

Its a good day out for families. My kids liked the smells most.
by Paul Barker
Fri Jul 19, 2019 9:28 pm
Forum: Everyones Projects
Topic: Small Push-Pull Amp.
Replies: 19
Views: 879

Re: Small Push-Pull Amp.

Nowt wrong with triode strapped valves. Some prefer gk71 over gm70. I liked 813 triode connected as much as I loved 211 for their unique stand out extra not heard in most amplifiers. Entirely different to each other yet only mood or tastes depending on which way your preference lies.
by Paul Barker
Sun Jul 14, 2019 4:40 pm
Forum: Everyones Projects
Topic: GM70 PP
Replies: 67
Views: 2248

Re: GM70 PP

Might find examples on Russian enthusiast forums, using a translator to help you find the talk. Or maybe a search under images will pull up a circuit.
by Paul Barker
Sun Jul 14, 2019 4:33 pm
Forum: Everyones Projects
Topic: GM70 PP
Replies: 67
Views: 2248

Re: GM70 PP

I’m not up to date on gm70 sweet operating position. Depends on so much. There must exist examples of pp gm70 circuits. Otherwise you’ll have to create push pull compound characteristic curves put in you’re loafline which links the two and choose you’re operating Point and limits. Should all be in R...
by Paul Barker
Sun Jul 14, 2019 4:15 pm
Forum: Everyones Projects
Topic: GM70 PP
Replies: 67
Views: 2248

Re: GM70 PP

Not relevant for our use of the valve. Look at the characteristic curves.
by Paul Barker
Sat Jul 13, 2019 7:57 pm
Forum: Everyones Projects
Topic: GM70 PP
Replies: 67
Views: 2248

Re: GM70 PP

On valve choice, 813’s on sale sh which I bought were wildly different transconuctance , I expect due to used ones, because of their intended use got a real pasting. Nos barely available. To find four used matching near impossible.

Get the new gk71 or gm70
by Paul Barker
Sat Jul 13, 2019 1:07 pm
Forum: Valves
Topic: uTracer 400V upgrade kit available...
Replies: 28
Views: 6994

Re: uTracer 400V upgrade kit available...

I killed my utracer a long time ago now. Decided to enquire from Ronald about a new 400v one built by him. But he came back offering to repair mine free. He truly is the most supportive inventor / supplier I’ve worked with. But I’ve replied asking him to repair and update mine, but I told him I want...
by Paul Barker
Sat Jul 13, 2019 8:04 am
Forum: Assorted Stuff
Topic: The Audio-Talk Motorcycling thread.
Replies: 488
Views: 43027

Re: The Audio-Talk Motorcycling thread.

jack wrote:
Fri Jul 12, 2019 8:10 pm
I had one of those on my desert Jeep...

Never ask a man walking away from camp with a shovel in his hand what he's up to...
Burying his daughters boyfriend?
by Paul Barker
Thu Jul 04, 2019 12:54 pm
Forum: Everyones Projects
Topic: Inverted OTL with 6SN7/6AS7
Replies: 93
Views: 4463

Re: Inverted OTL with 6SN7/6AS7

Looks organised.
by Paul Barker
Sun Jun 30, 2019 6:07 pm
Forum: Everyones Projects
Topic: Inverted OTL with 6SN7/6AS7
Replies: 93
Views: 4463

Re: Inverted OTL with 6SN7/6AS7

Addendum I see the up dated 400 max bolts utracer is only £283 built by Ronald. Worth every penny, but he’ll also send the upgrade to 400v for 15 💶 (they used to be 300v as is my one.)
by Paul Barker
Sun Jun 30, 2019 5:46 pm
Forum: Everyones Projects
Topic: Inverted OTL with 6SN7/6AS7
Replies: 93
Views: 4463

Re: Inverted OTL with 6SN7/6AS7

Plotting characteristics is easy, measuring is hard because you have to give a short burst of power (i.e the specific volts/current at the specific grid voltage) so as not to damage the weaker component parts such as grid. Best get or borrow a curve tracer. Mine broke and I’m so far from electronics...
by Paul Barker
Sat Jun 29, 2019 4:48 pm
Forum: Everyones Projects
Topic: Inverted OTL with 6SN7/6AS7
Replies: 93
Views: 4463

Re: Inverted OTL with 6SN7/6AS7

Sounds like a nice recipe