Marshall 100 PT with Marshall 50 OT, question please.

[loudthud]

Raise your hand if you don't know your rectifier circuits. Have you ever heard of the FULL WAVE BRIDGE? Do you know one if you see it? The 50W PT might be 600 to 650 VCT, the 100W PT might be 330 to 350VCT. Do you think a 2204 is going to work with a 250V B+?

Is there going to be a thread in the future... I put a 100W PT in my 2204, the B+ is only 250V and the bias Voltage is only -25V... Is my transformer bad? Then after two pages of wasted guesses and you figure out you need a full wave bridge, your bias circuit isn't going to work. Yes, I'm talking to you with your hand up.

[BStringThumper]

Thank you all for your input. I bought the correct 50W power transformer.

[olddawg]

Back in the day it was common practice to remove 2 output tubes from a 100w Marshall to tame it a bit. The missing tubes and impedence mismatch caused earlier breakup. I've seen amps run hard like this for decades just fine. What's the difference?

[pdf64]

Well, the ones I've tried it on sounded worse, as the HT nodes, especially when overdriven, were a lot stiffer. So the break up seemed harsher with less power compression
That put more voltage and dissipation stress on the EL34 and some couldn't take it, causing expense and delay to try out a bad mod.
To be fair, I've not tried it on any lower HT 100W Marshalls (are there any?), they all ended up over 500V at idle with 2 x EL34.

[olddawg]

Well, the ones I've tried it on sounded worse, as the HT nodes, especially when overdriven, were a lot stiffer. So the break up seemed harsher with less power compression
That put more voltage and dissipation stress on the EL34 and some couldn't take it, causing expense and delay to try out a bad mod.
To be fair, I've not tried it on any lower HT 100W Marshalls (are there any?), they all ended up over 500V at idle with 2 x EL34.

Yeah.. it is subjective like anything else with sound. Makes a difference on what guitar, pedals, speakers, genres, and settings. All I'm saying is I have seen people deliberately do it for decades. The scale up is different... kind of apples and oranges... but I just put together a 2x EL84 amp using a 4x EL84 PT. I did no modifications to the 2x EL84 circuit and drive the living sh@t out of it into a speaker attenuator. Everyone loves it.

[BStringThumper]

Hi pdf64,
I don't know if you saw my last post, I installed the correct 50W power transformer in the 2204. The reason I wired the AC HT wiring to the switch first is due to a video I watched on AC & DC switching. The DC switching was like watching someone arc weld as the two contacts separated on a blade type switch, not so with the AC voltage. I'm also running diodes instead of a tube rectifier, but thanks for pointing that out, I understand what you mean. I wish I would have powered up that 100W power transformer before I put in the 50W. Even with the 50W PT the plate voltage is 466 with 35mA 65% PD on the EL34 tube. My thinking was with the lower current draw on the 100W PT with two missing tubes is the plate voltage on the two tubes would be over the max plate voltage of 500VDC for the EL34 , just like you had mentioned, and that it is also the rating on the F&T filter capacitors. The 6550 tube can put out anywhere between 49W to 56W at 70% PD. I was concerned for my 50W output transformer. I've heard of people doing it, never seen it. I'm not willing to chance it.
Thanks again for everyone's input/replies. This is a great group!