Marshall 9100

[Clemford]

I might have a chance to buy one of these but I'm not sure if it's a good amp or not. From what I've read, Marshall's lack in the low end, especially these ones and the 5881's are less desirable than EL34's. Some seem to like these and some hate them. I prefer an amp with a chunky low end. Thin ones seem so 80's solid state sounding. It's in great cond. with little use for 300.00, possibly 275.00 Should I pass? Also, are there any Marshall heads that have the same power amp section that I can compare this to? There aren't many reviews on these to go by.

[Reeltarded]

1st... Lacks lowend? Grrrrrr.. and LMAO.

Rebias EL34. Change couplers to .1uF. $275? I'd buy one for that. heh

[roberto]

9100 has two pairs of 5881 and two completely separated power supply.
I had the 9200 and it was a bit colder than standard marshall power amps, but with tons of definition and a stiff low-end. If it doesn't need to be retubed, 275$ is really cheap!

[gary]

I'm sure there was a design fault documented for these. Something like the bias supply being the wrong side of a fuse ?? i.e potential for the power tubes to lose bias in an unrelated fault condition. Might be worth checking into and budgeting for a modification.

[roberto]

Never had problems with mine, neither eard of similar problems, but I think it's easy and cheap to fix something similar.

[Clemford]

I'm sure there was a design fault documented for these. Something like the bias supply being the wrong side of a fuse ?? i.e potential for the power tubes to lose bias in an unrelated fault condition. Might be worth checking into and budgeting for a modification.

I read that the schematic is correct but the board was wrong so it has to be hardwired like the schematic.

[Clemford]

1st... Lacks lowend? Grrrrrr.. and LMAO.

Rebias EL34. Change couplers to .1uF. $275? I'd buy one for that. heh

I've read a few reviews that it was sterile and had no low end. It came with 5881's. I have a quad of new Winged C's but I don't think they'll clear the cover unfortunately. Which caps are the couplers on the schematic.

[Clemford]

[quote="roberto"]9100 has two pairs of 5881 and two completely separated power supply.
I had the 9200 and it was a bit colder than standard marshall power amps, but with tons of definition and a stiff low-end. If it doesn't need to be retubed, 275$ is really cheap![/quote

I read somewhere that the phase inverters are not the usual design. I wonder if that could cause these to be cold or a bit sterile.

[roberto]

Yes, there is a 12ax7 with both triodes in parallel as an input stage (presence is a bright cap with a pot on the cathode), then a 12at7 as phase inverter:
http://www.drtube.com/schematics/marsha ... -60-02.pdf

Well, if I were at Marshall that time, I had arranged only one 12at7 for the input of both channels, and then the pair of 12ax7 for the PIs.