martin manning wrote:A Traynor has to have a Hammond PT, eh? ;^)
Didn't occur to me. But absolutely!
Ya, eh! For clarity not that organ company from Chicago.
<correcting sleepily reading off notes for ygm1 vs ygm3 specs>
The schematic calls for 400VDC and as Martin suggests something with a lower secondary and off their 300 series line would be an interesting upgrade tone-wise and for the life of power tubes. Kevin O'Connor suggests a stock 270fx (not 278x as I originally posted). Just ensure 6.3 filament current is ~3A (not 6A as I originally posted).
Best .. Ian
Last edited by didit on Sun Jun 21, 2015 1:18 pm, edited 1 time in total.
Barks, this PT is just too big for the amp. It could be that it was wound for a lower primary voltage, but there is also the fact that you are drawing much less current from it than what it was designed for (both HT and filament), and that is a contributing factor in the high secondary voltages too.
I opted for the 372, as mentioned, as it'll be closer to original spec.
I'm assuming it'll be easier to tweak plate voltage down than up - forgive me if that is a rookie error.
Looking over schematic and current inside pictures to correlate and understand the solid state rectifying circuit etc.
I know from the guys at Traynor that when they first re-issued the YGM3 a few years back, they just called Hammond and asked them to make the same transformers as they originally did... sadly, when they fired it up, it was a tube eating monster! THey had to re-work the transformer specs to bring downt he B+ in a big way. As i said in my own trials of Traynors and High B+ voltage, traynors run HOT! I forgot what my bass mate put out, I will check when i open it up this week to fix an issue i am having... but it was really high for a simple dual el84 combo. It also has a MASSIVE transformer, that is 100% stock. My Bassmaster put out crazy high voltage too, and I've gotten that under control with a 39 volt 10 watt zener at the moment. Still working that one out.
I didn't look carefully at the suggested Hammond specs - 300-0-300 w/ ss rectifier is gonna be a fire breather, you're gonna be swapping out el84s like they were bullets. Maybe the 370FX @250 would have been more modern, or the 275V mentioned as a compromise. At least it'll be vintage accurate and the preamp voltages will be as originally spec'd. Good thing the 300 series has a 240V tap and not 230V.
Might want to go for a (box) of the high power (JJ fat bottle?) or ruskie military 7189 types, maybe a vintage pair of USA 7189 is what's already there? ANOS USA 6BQ5s can be gotten for not crazy money off ebay, Matchless favored these in their hot amps, though they never got close to 400V. This thing's is fixed bias, right? At least you got that going for you. Maybe a fan?
BTW Is this the only EL84 fixed bias amp out there?
Well it'll be my 16th wedding anniversary next week. My wife will be treating herself to a £100 shopping spree in town. I will treat myself to a new Hammond PT. I have been given permission.
Forgot to mention: Dude! Buy the PT on your own tab, don’t make it your anni present, it’s supposed to be from her to you even if you are buying it yourself and have permission. Trust me, buy yourself something they can understand, a sweater, spiffy runny shoes, possibly a new set of BBQ utensils, a new shop-vac at the very worst. Don’t buy amp geek shit.
Oh well - what is, is!
Wife runs the business side of our studio so she understands!
It will be a vast improvement on the 7.5V and 456V currently.
At the moment It's got a pair of TAD el84's in. I've no idea what the fixed bias is set to or if it is even if it has ever been adjusted - I assume so.
The last pair of TAD's (that were already old when I put them in) were still working fine when I got these new ones - so I'm assuming them to be a robust tube.
Barks wrote:Oh well - what is, is! Wife runs the business side of our studio so she understands!
Five years from now you'll be playing your Traynor and go, "Honey listen, doesn't it sound just great!" And she'll say, "Yeh, sounds great. I still can't believe you bought a transformer to celebrate our 16th wedding anniversary."
It will be a vast improvement on the 7.5V and 456V currently. At the moment It's got a pair of TAD el84's in...The last pair of TAD's (that were already old when I put them in) were still working fine when I got these new ones - so I'm assuming them to be a robust tube.
Maybe it's biased super cold also adding to the high volatge, still all I can say is WOW. I would have figured this:
BTW which TADs?
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