If you have a 100 already and can play it, then why not? Make sure it has not been fiddled with too much, or can be returned to original specs.

I went to test it last night... Not good. The amp HAS been fiddled with, but it's expected things like 2 of the big caps thatvwere changed, probably a good few years back. The tubes are odd, since I can't see any brand on them, but the preamp tubes say Marshall.

The guy selling the amp is a drummer who knows NOTHING about amps. He's selling the cab as well but I'm not too interested. I had to take my own guitar for testing...
When we powered her up, he told me that it hadn't been powered up in a good few years. The bottles lit up and everything seemed ok... But... No sound. No hum, hiss, crackle, nothing. Checked the cab wiring and the jacks. Everything seemed ok. I switched her off and gave the guy an adjusted offer due to the fact that I will have to have it serviced.

I'm now considering that it may be the output transformer. I didn't check the fuses though. What else can it be?

Could be lots of things. If it's old then some other electrolytic could be dead, one or more of the tubes can be dead. The speaker cable could be broken, a pot (This happens often) can be so dirty that it doesn't let any signal through.

Just to add. For R7k you can't even buy all the parts the build a new one from scratch. A complete set of valves for that amp will cost about R2500 or so and a headbox is around R4000 and the innards around R5k to R8k. Keep that in mind ?

ez wrote: Just to add. For R7k you can't even buy all the parts the build a new one from scratch. A complete set of valves for that amp will cost about R2500 or so and a headbox is around R4000 and the innards around R5k to R8k. Keep that in mind ?

Yeah I made the guy an offer and told him that he can take his time to decide. I may be a little flexible on the offer. If it's a major repair that involves something like the OT and electrolytics, then I may as well butcher it and give it a master volume knob, but we'll see.

psyx wrote:

ez wrote: Just to add. For R7k you can't even buy all the parts the build a new one from scratch. A complete set of valves for that amp will cost about R2500 or so and a headbox is around R4000 and the innards around R5k to R8k. Keep that in mind ?

Yeah I made the guy an offer and told him that he can take his time to decide. I may be a little flexible on the offer. If it's a major repair that involves something like the OT and electrolytics, then I may as well butcher it and give it a master volume knob, but we'll see.

If its just the OT and electrolytics then its not so bad. Maybe R2k + labour. The problem with 100 Watters are the volume. Master volume won't give you the best sound and you need a really big($$$) attenuator to get them down to reasonable volumes. This is why I'm making a ±50 Watt version. Mostly the same tone but easier ($) to deal with.

Other than the fact that I could never use it with the volume over 2.5 and the fact that it needed a 4 x 12 cab, my old plexi Super Lead had the best tone out of any of the amps I've owned. EZ's idea of a 50W version sounds the business!

Chabenda wrote: Other than the fact that I could never use it with the volume over 2.5 and the fact that it needed a 4 x 12 cab, my old plexi Super Lead had the best tone out of any of the amps I've owned. EZ's idea of a 50W version sounds the business!

It's still going to be awfully loud. I bought a 100 Watt attenuator to deal with that. I think it'll actually be about 38-40 Watt, so I could probably *just* use it with my 2x12 without the attenuator, without blowing the speakers (no master volume).

With a 100 watter you can pull two of the power tubes and rebias it. The amp's output impedance will then be lower (I think) so you need to run the cabinet into a higher impedance setting to have them match again. So it'll effectively be a 50 watter. Not that the volume difference between 50 and 100 is that big.

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It's still going to be awfully loud. I bought a 100 Watt attenuator to deal with that. I think it'll actually be about 38-40 Watt, so I could probably *just* use it with my 2x12 without the attenuator, without blowing the speakers (no master volume).

With a 100 watter you can pull two of the power tubes and rebias it. The amp's output impedance will then be lower (I think) so you need to run the cabinet into a higher impedance setting to have them match again. So it'll effectively be a 50 watter. Not that the volume difference between 50 and 100 is that big.
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It certainly is if an over-driven driven valve, lead tone is what your after. If you are looking at a great clean rhythm tone that can be heard in a band setting then these amps are almost perfect. A tube screamer usually does a reasonable job of supplying a lead tone. Especially if the music that you are playing calls for 95% rhythm and 5% lead. Turning the volume up to beyond 4, using a tube screamer and 4 x 12, resulted in trouser legs being blown by the air pressure wave and rib cage vibration with my old one though.

A bit of a waste to use a Plexi Marshall as a 'base for pedals' dontchathink? (That's what Fender amps are for)

ez wrote: A bit of a waste to use a Plexi Marshall as a 'base for pedals' dontchathink? (That's what Fender amps are for)

:roflmao:

Perhaps in this day and age - BUT, when I was a younger man, where I lived there weren't too many options. I can remember going to a music shop and literally seeing piles of 60's Fender amps in a back room that had lost their smoke. You would have had a heart attack! The old Marshalls were the holy grail and I can remember us all plugging into the bass guitarist's one once for a jam session! They would work in any sized venue and as we had such crap PA gear and couldn't mic up(we were even using old Echolettes from the '50's with a roll of 1/4" tape and sellotape for the echo and a decent mic was another story too!), sometimes you needed the volume for your guitar(stuff the vocals!!). A tube screamer was the way forward - and your next dream was to get an analogue delay pedal or some form of reverb.

I did have some beautiful looking Fender amps, a white Tolex Bandmaster was one of them but it sounded too thin and weedy. The only one I ever liked was my '64 Princeton that I recently gave to Attilla.

Chabenda wrote:

ez wrote: A bit of a waste to use a Plexi Marshall as a 'base for pedals' dontchathink? (That's what Fender amps are for)

:roflmao:

Perhaps in this day and age - BUT, when I was a younger man, where I lived there weren't too many options. I can remember going to a music shop and literally seeing piles of 60's Fender amps in a back room that had lost their smoke. You would have had a heart attack! The old Marshalls were the holy grail and I can remember us all plugging into the bass guitarist's one once for a jam session! They would work in any sized venue and as we had such crap PA gear and couldn't mic up(we were even using old Echolettes from the '50's with a roll of 1/4" tape and sellotape for the echo and a decent mic was another story too!), sometimes you needed the volume for your guitar(stuff the vocals!!). A tube screamer was the way forward - and your next dream was to get an analogue delay pedal or some form of reverb.

I did have some beautiful looking Fender amps, a white Tolex Bandmaster was one of them but it sounded too thin and weedy. The only one I ever liked was my '64 Princeton that I recently gave to Attilla.

The Marshall Bass models sound really good. Which is why the one I'm making is a Lead and Bass in one ?

I had one - a 1970 100W that was very similar to the Super Lead. The guy I got both of mine from preferred the Bass for guitar - But then, he played a Les Paul....

psyx, sorry for the hijack there. I'll just leave this here.

ez wrote: psyx, sorry for the hijack there. I'll just leave this here.

Nah that's totally related! So no hijack there ?

ez wrote: A bit of a waste to use a Plexi Marshall as a 'base for pedals' dontchathink? (That's what Fender amps are for)

My super bass is a super pedal platform! Works super well with tube screamers and muffs. It actually nails the big muff tone to the letter. Which is what I intended to use it for anyway.

If you're using the big amp as a platform for pedals I'd say you won't gain anything by getting a Superlead. The lead version has less headroom than the bass and will be a bit less bassy and a bit more trebly but all in all they will sound very similar if used like this.

ez wrote: Master volume won't give you the best sound and you need a really big($$$) attenuator to get them down to reasonable volumes. This is why I'm making a ±50 Watt version. Mostly the same tone but easier ($) to deal with.

There are master volumes and there are master volumes. I ditched the Lar/Mar setup I initially installed in mine a while back in favour of an alternative design that has also been around for a long time, but that responds exceptionally well to the choice of pot. This setup leaves me wanting for nothing tone wise at any volume.

Here's a link to the video that made me change my MV setup to its current setup:

shaunf wrote:

ez wrote: Master volume won't give you the best sound and you need a really big($$$) attenuator to get them down to reasonable volumes. This is why I'm making a ±50 Watt version. Mostly the same tone but easier ($) to deal with.

There are master volumes and there are master volumes. I ditched the Lar/Mar setup I initially installed in mine a while back in favour of an alternative design that has also been around for a long time, but that responds exceptionally well to the choice of pot. This setup leaves me wanting for nothing tone wise at any volume.

Here's a link to the video that made me change my MV setup to its current setup:

How does this one work?

Edit: That does sound pretty good ? (I have already bought the attenuator haha)

It's wired Rich Mod style, and uses a specific PEC pot.