audio-talk

simon wrote: I take back what I said about this being a cheaper hobby than golf....

I thought we agreed not to mention that word

Shhhhh! Say nothing! There are golfists everywhere...

steve s wrote: I emailed Pieter last night for a quote for some new transformers...
This affliction is a bugger

(a) I hope you have more success getting hold of him than I have - been trying to agree some amount of money to pay him, for a couple of weeks now ...

(b) What's your spec for these , Steve ? - just curious . What supply voltage - and cathode bias or fixed bias ? . Mine are 7K> 8/4R and good for about 10-12W . Sufficient for me running GM70 at about 720V B+ and cathode-bias , or a little more perhaps .

="IslandPink(a) I hope you have more success getting hold of him than I have - been trying to agree some amount of money to pay him, for a couple of weeks now ...

(b) What's your spec for these , Steve ? - just curious . What supply voltage - and cathode bias or fixed bias ? . Mine are 7K> 8/4R and good for about 10-12W . Sufficient for me running GM70 at about 720V B+ and cathode-bias , or a little more perhaps .

well mark the last time i used them it was on 5 k transformer... i think?

i need 10-12 k, i was thinking of running them lightly loaded at around 600 volts, although they will take 1200... i'm not going there
i remember them sounding ok. so i will see, I think the gain is about 11 so its an easy amp with about 40v + bias,
I would guess the price pf the transformers may well put me off though

steve s wrote: i need 10-12 k, i was thinking of running them lightly loaded at around 600 volts, although they will take 1200... i'm not going there

Dunno if it helps ya our-steveS but I've got a pair of 10/14K SE Hashimoto's not being used at the moment, I don't want to sell them but you're welcome to borrow with them if you're not too sure about the project being a keeper Steve.

These....


Spec -> http://www.tube-amps.net/images/Hashimo ... U_1024.jpg

DTB

Thats really great dave, let me see what Pieter comes up with 1st though


Thanks ...

Hashimoto have a good reputation, but I don't think those transformers are big enough for the GM70.

Paul Barker wrote:Hashimoto have a good reputation, but I don't think those transformers are big enough for the GM70.

I think he wants them for vt25 ???

steve s wrote:Whilst listening to Simons amps with the copper valves it made me think about those old british vt25's i have, they are close to 211 but close to the resolution of the px25, with some suitable outputs i guess they would sing

but now I'm getting confused.......

isn't vt25 a type10 equivalent?...if so it's only good for about 1.5 watts, or am I missing something??

diet: even more confused...there is another vt25 as designated by GPO and is LS5 equivalent, but that seems even smaller than the other one...there is no data that I can find for this one though.

Pauls rights i really need around 100+H for the vt25 .. But i did not want to turn Dave's offer down to quickly they are more suited than anything i have at the moment.. They may work if i run them lightly on the higher impedance windings
Its the british vt25 (DET25) not the us version.

There are two versions of the det 25 the early version that came out in the mid 30's and the later wartime version, they are really different valves
The early versions could not cope in aircraft , the later ones could,

Hello Ed. You're not the only one who is confused but there is hope. After hours of looking at data books I have finally sussed it out. The problem is there are two series of VT valves, one British and one American and valves with the same number are completely different. In this case the American VT 25 is cv603 or 210 while the English one is cv1025 or det 25. They are both triodes but that is the only similarity as far as I can see.

I have researched this topic because I have a large number of cv1094s which I believe are the military version of cv1025 but I haven't been able to get much out of them so far.

Hope this is of some value. Steptoe

Steptoe wrote: I have researched this topic because I have a large number of cv1094s which I believe are the military version of cv1025 but I haven't been able to get much out of them so far.

Hope this is of some value. Steptoe

CV1094

http://www.radiomuseum.org/tubes/tube_cv1094.html

http://www.r-type.org/exhib/aaj0076.htm

If you want a ready made GM70 amp, see these.

http://www.ebay.co.uk/itm/GM-70-Triode- ... 19e9049dfd

http://www.ebay.co.uk/itm/Paralle-Singl ... 19e9d69d3f

http://www.ebay.co.uk/itm/TRANSCRIPTION ... 3386c70001

pre65 wrote:

Steptoe wrote: I have researched this topic because I have a large number of cv1094s which I believe are the military version of cv1025 but I haven't been able to get much out of them so far.

Hope this is of some value. Steptoe

CV1094

http://www.radiomuseum.org/tubes/tube_cv1094.html

http://www.r-type.org/exhib/aaj0076.htm

They are a rare valve, i have one, and I've never seen any others..

How many do you have, would you part with a couple or more?

They are a rare valve, i have one, and I've never seen any others..

How many do you have, would you part with a couple or more?

Foot in mouth...

Will wrote:
Foot in mouth...

nail on head Will, nail on head!