Search found 116 matches

by ACPEN
Sat May 28, 2022 8:19 am
Forum: Speakers
Topic: Much modified Wharfedale Denton
Replies: 3
Views: 350

Much modified Wharfedale Denton

On a whim, I bought a pair of early Denton's for £20 (too much!) Not sure quite what I had expected but although drivers were in good shape they sounded aweful - no bass and very 'nasely'. I liked the boxes though - so decided to install Seas 18w 8452 00's that I' purchased in '99 and been used in a...
by ACPEN
Wed May 04, 2022 6:47 pm
Forum: Speakers
Topic: Kef Concord loudspeakers.
Replies: 22
Views: 19613

Re: Kef Concord loudspeakers.

Well, it seems to have taken me 12 years to find this thread! However, I've had the pictured set up around the same time so thought I might show it - as was mentioned, the original KEF arrangement was awful but the box and bass driver I kept - the box on top contains Monacor drivers and homemade xov...
by ACPEN
Wed Jan 26, 2022 2:35 pm
Forum: Buying and Selling
Topic: 3C24 MARSHALL etc
Replies: 0
Views: 480

3C24 MARSHALL etc

Hello,

Does anyone have one of these they could bear to part with?

Thanks

AC/PEN
by ACPEN
Wed Jan 12, 2022 4:16 pm
Forum: CD
Topic: CD
Replies: 0
Views: 627

CD

Cambridge Audio AZUR 640C CD player

Hi,
Recently acquired this player with only the RH output working - the coaxial o/p is fine through my AN dac - so why bother? well, just wondered if anyone has had similar problem (and the cure.)

Thank you

AC/PEN
by ACPEN
Sat Nov 13, 2021 11:19 am
Forum: Everyones Projects
Topic: TIM MELLOW OTL
Replies: 3
Views: 885

Re: TIM MELLOW OTL

Please search under Tim Mellow OTL - thats how I found it (had forgotten I'd written it!)
by ACPEN
Sat Nov 13, 2021 10:57 am
Forum: Everyones Projects
Topic: TIM MELLOW OTL
Replies: 3
Views: 885

TIM MELLOW OTL

Please see my note on the Tim Mellow OTL offered in the Buying?Selling section.

Rgds

ACPEN
by ACPEN
Sat Nov 13, 2021 10:54 am
Forum: Buying and Selling
Topic: TIM MELLOW OTL
Replies: 0
Views: 723

TIM MELLOW OTL

Hello In 2010/11 I reported on building the 6C33c OTL by Tim Mellow for my son-in- law and a version using 6C41's. The original 6C33 version is now for sale should there be any interest - offers please. It was described with photos in the thread at the time. It is now 10 yrs old and has been well us...
by ACPEN
Thu Jul 22, 2021 12:36 pm
Forum: Valves
Topic: Class A2 - heater hum
Replies: 7
Views: 1548

Re: Class A2 - heater hum

Yes, thats about where I'd got to - but dont understand the mechanism of why it happens.
Thanks for your thoughts.
Rgds
David
by ACPEN
Thu Jul 22, 2021 12:16 pm
Forum: Valves
Topic: Class A2 - heater hum
Replies: 7
Views: 1548

Re: Class A2 - heater hum

There is a null but still a loud hum with some valves noticeably worse than others - thats the bit I dont quite understand - I appreciate that the higher heater voltage may well contribute to this, but why only some valves.....
atb

David.
by ACPEN
Thu Jul 22, 2021 10:08 am
Forum: Valves
Topic: Class A2 - heater hum
Replies: 7
Views: 1548

Class A2 - heater hum

Hello I've built several A2 amps over the years usind DC filament heating - no hum problems mainly using 811a and DA41 / TZ40 types. Thought I'd try ac heating this time with humdinger pot. Results vary depending on type of valve used - with 6v 811a and 812a, no problem but with 7.5 types DA41 / TX4...
by ACPEN
Fri Jun 18, 2021 8:24 am
Forum: Everyones Projects
Topic: 45 SE
Replies: 170
Views: 28609

Re: 45 SE

Re last post - Age related memory error(!)
H30 is mu 80 and has the interesting and unusual specs for the time.
😁
by ACPEN
Fri Jun 18, 2021 7:33 am
Forum: Everyones Projects
Topic: 45 SE
Replies: 170
Views: 28609

Re: 45 SE

Might I suggest as contemporary (ish) the 4D1 Brimar (12v htr) or Osram H30 (mu 40) or the Osram H42 (mu 100 - 4v htr) interesting specs for this one - all B7 base. H42 listed as suitable to drive PX4.
Used them all to good effect ....
Rgds
AC/pen
by ACPEN
Tue Mar 09, 2021 3:14 pm
Forum: Everyones Projects
Topic: Osram 2v battery valve SE amp
Replies: 12
Views: 3915

Re: Osram 2v battery valve SE amp

Hi Dave - pleased to hear from you, and yes, correct!
All you need to now is explain whats going on....

😁
David.
by ACPEN
Tue Mar 09, 2021 10:49 am
Forum: Everyones Projects
Topic: Osram 2v battery valve SE amp
Replies: 12
Views: 3915

Re: Osram 2v battery valve SE amp

Following on from the above, I searched for any original use of the HF tetrode (S23) in legacy radio's of the pre war period - I found a service sheet for a Philips radio (1935) in which an equivalent (PM12a) was used, unusually as an audio amp. The interesting thing is that it appears to be used wi...
by ACPEN
Wed Feb 17, 2021 6:45 pm
Forum: Everyones Projects
Topic: Osram 2v battery valve SE amp
Replies: 12
Views: 3915

Re: Osram 2v battery valve SE amp

Audiojumble Tonbridge many years ago - always worth a visit, but when?
David. :D