audio-talk

Ooops!
E810F or E180F pin compatible if you leave pin 6 disconnected.

Just to say that have broken with tradition (my own) and have tried a 'modern' approach as a driver - an E810E ! in pentode mode - 10k load, 150v S.G, 100R bias. 200v ht, runs at approx 14mA - sounds Good, certainly worth a try if anyone is still looking for driver options for the PP3521 triode. To ...

Thanks Greg,
Didn't know that...

Since the replies to this post I have been playing with a Hammond 20H 20mA choke as anode load for an ML4 driving a KT8c - surprisingly good results but as expected being rather challenged at low audio frequencies.... Wondered if anyone might know of a pair of Hammond 156C chokes looking for a new h...

Thanks Paul,
Yes of course, I actually checked the inductance after sending the email....

CCS it is then!

Thanks.

Any one tried using Hammond 125BSE output's as load for driver stage at around 20mA.....any practical experience?
Or, waste of time...
Thanks.

Haven't built a PP amp since 1962 - but have you thought of the 6Y6, a very capable driver......

Yes, I like the PP3521 and have done for some time, also the PEN3520 which although a pentode makes a reasonable sub and can be a direct plug in. I too have used the USA types, UY-227 and UY- 224 (tetrode) but came back to the British types of the same period, MH4 being also from the 30's. Be intere...

Hi - I too have tried the PP3521 in SE using drivers recommended to drive PX4's but was never happy with the results - these were the H42 and AC/S2PEN types. Since seeing this thread I decided to try again using MH4's as drivers- good, but slightly low gain, I then tried MH4's in mu follower configu...

Sketch of cct - told you it wasn't anything special!

Valves are 6SJ7 6Y6 PT15

Hello Mike It is a long time Tonbridge I think.....Danbury was a loss, still have transformers working! I'll do a sketch (sorry no cgi here!) It's basically just the usual A2 format but using +ve drive to g1 + g2 strapped - works with most transmitter pentodes to varying degrees. Nothing new or spec...

Recently cobbled a 2E22 se A2 amp (g1+g2 driven) - excellent results. On a whim I substituted PT15's - now like many, I've used PT15's in class A with good results but not A2. Taking care not to overrun g1, results are comparable to the 2E22. Also careful to connect g3 to filament mid point or can o...

Me too

Couldn't agree more! recently put together a PSE 1619 SE amp (295V ht - 3.5k load - driven by 12gn7 a'la Pete Millett) very sweet sound + 1619's £8.00 from Langrex!) and ac htrs are fine!

Thank you Nic for your observations on using the 3C24 - pleased to say I was aware of modt of its foibles, but good to have them confirmed. Look forward to hearing the results of your tests. And thank you Nik for your thoughts too. You may vaguely remember that some years ago I posted several notes ...