recommended Output TX's for PT15 ?

[Pedro]

James,
I've tended to use Celestions ( Vintage 30's and Classic Leads mainly ) as well as old fanes when I can get my hands on them. Lovely in low powered EL84 amps.

It seems the Eminence range ( esp the Red, White and Blues) now get a good write up ( especially with the Americans on the Dumble discussion boards etc ) but I havent tried any yet.

At present my fave amp for gigging ( with my beloved 1994 PRS McCarty ) is my 18watter - with Mullard EL84s and Telefunken Ecc83s courtesy of SteveS.

I'd be very interested in hearing more about your guitar amp designs. I'm just knocking up a plexi 50w copy but the damn Dagnall power TX had a short and fried ! Also I have a spare JJ 300B I want to put to use in a practice amp for my own use.

Regards
Pete

[James D]

Pete,

I like the Vintage 30s - not so enamoured with other Celestions other than the cheapo 12" Rocket 50.

I like some of the old Celestions such as the G15M and Audiom 12-P for instance. Old Fanes are really nice

The Em Cannabis Rex is "awsome" (to quote my son who is a Vintage 30 fan) - I like then a lot too.

I put up a couple of guitar designs over the next couple of days using non-standard valves.

James

[Pedro]

I'll really look forward to that - but I hope that it doesnt slow me down ( even more ) on the PT15 build !!!

If you have any ideas for the 300B let me know.

I thought maybe I could gut my champ 6V6SE clone and have a 300B champ !
Might make a very nice practice amp indeed - Ive seen Gordon Rankin is building some pretty interesting guitar "engines" at present. Apart from those I've never seen a 300B used in a guitar amp !

Meanwhile the Dumble ODS clones are the most interesting and rewarding sound-wise Ive come across so far - pretty complex to build and tweak to find the elusive "sweet spots" though.

Rgds
Pete

this is getting very OT from the wonderful PT15 now so I'll stop.

[Pedro]

Right....

Nick has very kindly loaned me 2 of his 10K 211 TXs which are fitted to the board this afternoon ! Thanks Nick.

Now that I have some time on my side to choose carefully I wondered if there wil be any merit in ordering and waiting for AE's 10K ( 70ma ) TXs with amorphous cores. They sure look nice and I know Nick reckons they are worth the extra expenditure for the detail. I'm just selling on some band gear so may have the extra funds soon !

Question is, Is it worth doing it for the PT15 or is the ATH40 TX ( 6K5 ) from AskJanFirst just as good for the PT15 SE do you think ?

Meantime , I was gutted not be able to make Eggfest due to family commitments yesterday, but it was great to see Nicks set up and listen to a few tracks today through the OBs.
It was a taste of what I'd missed, but also was a great motivation to get away from repairing a couple of guitar amps and get moving on James's SE PT15/C3g design.

anyway, all views on suitable TXs for the PT15 most welcome, while Nick has sorted me out with the temporary 10K's

cheers
Pete

[James D]

You will hear a difference with the 10K amorphous compared to any normal iron trannie. The amprphous will be clearly better and so they should be for twice the price....

The ATh40s are excellent sounding and value standard iron output trannies - the amorphous are a real step up from that.

James

[Pedro]

Hi,

Would the ATH45's be a better Ask Jan First TX for the PT15 - they are 9.2K primaries, but are designed for 211's ?

I havent been able to get a reply out of AE in the last week so I think I may go for the ATH's ( ATH40's or 45's depending on advice ! ) and buy my chokes from Jan at the same time.

Based on what Steve, Corne and Walter are saying about the PT15 I think I may well be satisfied with the sound with the AJF tx's and save for the AE amorphous later on as an upgarde after circuit/component upgrades.

cheers
Pete C

[James D]

Pete,

I wouldn't go for the ATH45s.

I would consider the ATH33 which is a 10K transformer with taps at 6K and 8K so you can play with the OPT impedance. They are €141 each so a bit more money.

If you use Corne's excellent spreadsheet you can see that as the B+ goes up so the optimum OPT impedance goes up to, the ATH33 would let you play with different B+ voltages

I must say I was settling on Va=600V, Ia=50mA or 60mA and Vg=-70V as a nice OPT - with an 8K OPT setting it looks like 7 to 8 watts output.

James

[bouncy ball]

Hello,

"I would consider the ATH33"

ATH33, What brand is it? I am interested.

Thanks

Walter

[James D]

Hello Walter,

They are from AskJanFirst

I find Jan very helpful and with excellent service and products.

James

[Pedro]

James,

yes - a couple of primary load options- i think this is probably the best option for me at the moment

Many thanks for the tip

Pete