Taming the beast

[Gibsonman63]

I picked up a 1980 Marshall 1959 head (Plexi Circuit) recently. Last week I decided to field test it at my Thursday session. This amp has unbelievable volume. I have other 100Watt amps including a 1979 JMP, but this one is insanely loud. I pulled two tubes and turned my cabinet to the wall, but it was still entirely too much. This amp would be perfect in a large arena show in the 1970's.

I have not heard an attenuator that has impressed me enough to spend $300 bucks on.

Any suggestions? Maybe a larger grid resistor or grid bleed on one of the inputs or would that just be asking for a bunch of amplified noise?

I am not so attached to it that I wouldn't consider selling it to someone who wants to get even with thier drummer.

[Phil_S]

If this amp is in close to original condition and the "real deal", I'd be hesitant to do any permanent mod to it.

If you have an extra hole in the chassis or can find a place to make one that isn't too destructive (maybe somewhere on the rear), look into the Hall VVR. http://www.hallamplification.com/main.html?src=%2F#2,2 This will allow you to control the loudness without neutering your amp.

[Gibsonman63]

I haven't opened it up to look inside (yet), but from outside appearances, it seems to be unmolested. It has the four inputs and I have seen people use an input hole to install a Master volume.

[Alexo]

You could throw a few Zeners in line with the B+ to drop down your power, you could even probably get away with throwing some 6V6's in it if you get the load to 6K6/pair or 3K3/quad and tweak the bias voltage. I would use JJ's for those kinds of voltages.

But as has been said, with an old Marshall, you're probably better off keeping it as it is and finding a different amp that suits your needs.

[Phil_S]

See if it's possible to swap an input hole for the VVR. Do it so it's totally reversible. This will beat the pants off any attenuator. If this is the one with the vertical inputs, and it is unmolested, you have a valuable amp. Don't mess it up.

[Richie]

the VVR is for 50 watts or less

[Scumback Speakers]

If you need a good attenuator you should look at the Alex Attenuator. I have one and it works well, right up there with the HO/Ultimate and Faustine.

http://www.myspace.com/alexsattenuator

[CaseyJones]

I picked up a 1980 Marshall 1959 head (Plexi Circuit) recently. Last week I decided to field test it at my Thursday session. This amp has unbelievable volume. I have other 100Watt amps including a 1979 JMP, but this one is insanely loud. I pulled two tubes and turned my cabinet to the wall, but it was still entirely too much. This amp would be perfect in a large arena show in the 1970's.

I have not heard an attenuator that has impressed me enough to spend $300 bucks on.

Any suggestions? Maybe a larger grid resistor or grid bleed on one of the inputs or would that just be asking for a bunch of amplified noise?

I am not so attached to it that I wouldn't consider selling it to someone who wants to get even with thier drummer.

Just sell it to Eric Johnson and call it a day.

[Andy Le Blanc]

I frigged around with that light bulb attenuator the popped up in the forum.

It works, put an insert on the CT of the PT HT if I remember, on the ground
side of a bridge rectifier I suspect. To a row of sockets all wired parallel.
Try bulbs of different wattage's etc, It works pretty well.
I was surprised, the quality of tone down to half volume was good.

[Gibsonman63]

Light bulb limiting sounds like something interesting to try. I generally use a light bulb limiter to fire up amps that I have recently worked on. I have noticed that you can play through an amp and it, just not really loud, but louder than you would think and it doesn't seem to effect the tone.

[dartanion]

A 100W Marshall is a loud beast when running correctly. Some of those other 100W units that you have played were probably not running optimally. If you need it to quieter, an attenuator or less eff. speakers would help, but it's still going to be really loud. Pulling 2 power tubes isn't really going to help much as 50W is still freakin' loud.

You can do a DIY Airbrake attenuator. Just search on it here and there should be a few build threads. Skip the Ultimate Attenuator as it's not really an attenuator at all but more of a reamp (read, large load resistor off the amp's output into a small SS amp to the speaker). I have heard lots of good things about the Aracom Attenuator too.

[Roe]

larmar ppmiv, alex attenuator

[Phil_S]

the VVR is for 50 watts or less

Hmm....sorry, I didn't realize. Maybe you can put in two of them ?

[Gibsonman63]

Would it be possible to run this amp with a couple of 6V6s? I would guess that I would need to get the bias in range before swapping tubes. This would bring it down about 6 dB which would probably be about right.

Any thoughts on Yellowjackets?

http://www.thdelectronics.com/pdf/yj.pdf

Running two EL84s would work.

[Phil_S]

A single pair of 6V6 want to see an output primary of either 8K or 6.6K. You've got four EL34 in the amp? That output primary is probably around 2K (give or take a few hundred ohms). This is, IMO, too much of a mismatch.

I have no experience with Yellow Jackets. I understand they are safe to use. I am guessing they change the tone somewhat.

Remember, when you pull two tubes, the output transformer "requirement" doubles, from probably 1.7K to 3.8K. This means the secondary outputs also double, so that the jack (or selector switch setting) marked 8 ohm becomes 16 ohms, etc.

Some things to think about...

Really, I can understand being enamored with this amp. It is, historically, of significant importance to guitar players. In addition, you say that yours sounds exceptional and I don't doubt it. It's just that you really can't use this amp, can you? Painful that it is, if you can't afford to mothball the amp, sell it and get something really nice that is useful to you. For what I guess this amp will bring, you shouldn't have much in the way of monetary limitations for your new amp.