If I tell you about an Idht similar to px4?

steve s · Post by **steve s** » Mon Aug 12, 2013 10:55 pm

Heres the cooking version, i believe the last version with the grey anode
These are marked up as osram, marconi, cosser and farranti, which has a slightly darker anode due to a few years in one of my amps.

steve s · Post by **steve s** » Mon Aug 12, 2013 11:00 pm

Hers some mullard made ACO44 some of these marked up as cosser and tungsram with respective numbers 4xp and pp12/250

steve s · Post by **steve s** » Mon Aug 12, 2013 11:12 pm

A few boxed ones

Thats it for tonight i have some mazda pp3/250 and some cosser made 4xp which has a slightly smaller anode on the lines of the cosser 2p but i'm not sure where they are.. I will have a route around for them.. More pics?

Paul Barker · Post by **Paul Barker** » Tue Aug 13, 2013 7:25 am

Thank you Steve. I noticed you refrained from commenting on sound.

Daren preferred the ones with cooling fins between those and the cooking ones.

I take it as read balloon's are better?

Have you an AD1 anywhere? I think I have one with the odd base not sure what it's called but also I think I have one in a BR4 base, though that one ought to be called something else instead. Very odd.

Maybe when we get together for valve testing session we can have a px4 listening session?

pre65 · Post by **pre65** » Tue Aug 13, 2013 9:21 am

Thanks for the PX4 tutorial Steve, I never knew there were so many variations.

steve s · Post by **steve s** » Tue Aug 13, 2013 4:17 pm

Paul Barker wrote:Thank you Steve. I noticed you refrained from commenting on sound.

Daren preferred the ones with cooling fins between those and the cooking ones.

I take it as read balloon's are better?

Have you an AD1 anywhere? I think I have one with the odd base not sure what it's called but also I think I have one in a BR4 base, though that one ought to be called something else instead. Very odd.

Maybe when we get together for valve testing session we can have a px4 listening session?

Its best to refrian from talking about the sound, i have cloth ears anyway.. The older ballons in my view are very good, there is a noticable difference in my opinoin

No AD1 unfortunately....i wish
the nickel anodes are usually a good sound, they usually have the cooling fins too.. I both like the look and the sound, although there is not alot in it across all of them there are really subtle differences...
Still awaiting the new transformers from pieter when i get them i will knock up a breadboard to test them out, maybe i can use it for px4 too as well as the px 25 .. that would be a good session to those interested

I will load up some more pics when i find the other valves..

Thanks phil for the comments.. Cheers

Steve

IslandPink · Post by **IslandPink** » Tue Aug 13, 2013 8:22 pm

I can see you really got into your stride there, Steve !
Very nice to see them .

PX4's and Pieter's iron should be a wonderful combination.
What sort of 'lams' are you asking for ?

Paul Barker · Post by **Paul Barker** » Tue Aug 13, 2013 9:28 pm

My single D1 is having it's first ever set of curves traced.

Phew, it is a goodun!

This bottle looks the same but has a BR4 base and is a Tungsram SPEZIAL. It was sold to me as an AD1.

Interestingly the two traces are virtually identical.

Andrew · Post by **Andrew** » Tue Aug 13, 2013 9:48 pm

That looks pretty linear too!

JamesD · Post by **JamesD** » Tue Aug 13, 2013 10:21 pm

You have a pair of AD1s!!!

Wow! It will be really interesting to see how they compare to PX4s... It looks really linear with the -50 line just starting to curve away from the others... Nice!

Paul Barker · Post by **Paul Barker** » Tue Aug 13, 2013 10:22 pm

The Cossor 4XP in the same envelope as the above two AD1 and AD1 SPEZIAL is clearly not the same valve.

Likewise the cooking Osram PX4 has a darkened part on the anode so has probably had a hard life.

Finally a Nickel anode PX4 with cooling strengtheners looks healthy but not the same as the AD1's which in my view look very interesting, to the degree an AD1 amplifier shall be considered, all be it with dissimilar bases.

Paul Barker · Post by **Paul Barker** » Tue Aug 13, 2013 10:25 pm

So for comparison here is the best PX4 trace next to the best AD1 trace.

The PX4 shows 833 ohms the AD1 660 ohms both measured on the straight section of the 0v line, which is about right for each valve.

interestingly the cooking px4 and the 4XP are fairly similar to each other. they would make an amplifier together.

IslandPink · Post by **IslandPink** » Tue Aug 13, 2013 10:29 pm

They both look absolutely top-notch !
I don't suppose you have an AD100 though ? !

Paul Barker · Post by **Paul Barker** » Tue Aug 13, 2013 10:30 pm

Paul Barker · Post by **Paul Barker** » Tue Aug 13, 2013 10:33 pm

JamesD wrote:You have a pair of AD1s!!!

Wow! It will be really interesting to see how they compare to PX4s... It looks really linear with the -50 line just starting to curve away from the others... Nice!

Yes it is easy to understand why they fetch high prices.

audio-talk

If I tell you about an Idht similar to px4?

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