Old Marshall Plexi: Fully Wide Open video

That's the way we used to play. Wide Ass Open. Didn't matter if it was Marshall, Fender, Traynor, Sunn, or even old tube Univox. It was the only way to get any dirt without using a fizzface or fizz/wah as these were about the only pedals around. No master volume either. Sometimes it was hard to even hear the drummer.
 
flatrockmobile said:
That's the way we used to play. Wide Ass Open. Didn't matter if it was Marshall, Fender, Traynor, Sunn, or even old tube Univox. It was the only way to get any dirt without using a fizzface or fizz/wah as these were about the only pedals around. No master volume either. Sometimes it was hard to even hear the drummer.
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Still the best way....
 
I think the first video that 100 watt Marshall is in dire need of service that hiss is off the charts. A real Plexi Marshall in good working order is capable of producing 188 watts.
Now that Ken Fischer has been dead for 11 years. Ken had an extensive modification for 100 watt Marshall's 1st most 1959 100 watt Marshall's had a plate voltage of 470 VDC and wall voltage
back in the 1960'S was around 110 VAC so plate voltage could be as high as 520 VAC. Next Ken would drop the input voltage so on the plate's would be 375 VDC and replace the EL34's with 6V6
Now the filament voltage would be to low so a new filament transformer would be installed. Next on V-1 the first preamp tube 12AX7 on a stock Marshall the plate resistors are 100k with a 820R
bias resistor Ken would change the second 100k resistor to 220k with a 2k7 what that did was give you the cranked Marshall sound and just turn down the volume pot on your guitar to get a clean sound. Next a Marshall phase inverter is 100k 82k you want a 7-8 volt differential. Some stock Marshall's have this with 5% resistors most don't so one out of 25 sing stock.

I serviced Ken's amps on the west coast Now I let the cat out of the bag.

Ken F_.jpg
 
^^ I don't know about the technical stuff, but you are right that something was drastically off with that amp. Sounds awful.
 
I encountered some really bad noise with a JTM-30 once. It turned out to be a bad stage ground....only my tube amp was affected.
 
Marshall Related: I wonder why people clip the 'C19' bright cap in the DSL40C's???? It does NOT sound good in a stage volume setting....
 
Robert Herndon said:
Marshall Related: I wonder why people clip the 'C19' bright cap in the DSL40C's???? It does NOT sound good in a stage volume setting....
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I think some people complain that the red channel is too bright. But they don't disclose how hard they are running their amps. Lot of them seem to like this mod.

I have two JCM800 50 waters. A real Marshall and a, uhm, unreal Marshall. Lot of people encourage clipping the Bright cap on the JCMs. Personally, I hate it. At least put it on a switch. It all makes sense when you start making the amp work. And of coarse, the volume is tremendous at that point.
 
syscokid said:
Does this reduce volume and power using the 6V6's?
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Yes some what its still loud. I have a Express amp with 6V6 pair that will make your ears bleed.

I still love Marshall's down to 3 each 1/2 stacks 1- Park 75 1969 1- Super Tremolo 100 1967 1 Super Lead 100 1968 The EL34/KT77 is one of my favorite sounding power tubes of all time.

The best sounding amp I own is a ODS-50 I built it's two channel with Marshall transformers master volume for the clean channel and master volume for the overdrive channel
471 B+1 with KT77'S in combo form EVM-12-S speaker.

EL34 Mid Plate Skyliner 50 Watt 001.JPG

EL34 Mid Plate Skyliner 50 Watt 002.JPG
 
syscokid said:
I think some people complain that the red channel is too bright. But they don't disclose how hard they are running their amps. Lot of them seem to like this mod.

I have two JCM800 50 waters. A real Marshall and a, uhm, unreal Marshall. Lot of people encourage clipping the Bright cap on the JCMs. Personally, I hate it. At least put it on a switch. It all makes sense when you start making the amp work. And of coarse, the volume is tremendous at that point.
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Same amp I used to use "back in the day" and no doubt it was loud enough to stop your heart. Never thought of modding it ever, not once, not for a moment. And it was utterly reliable, at a time in my life when I knew nothing of caring for things or tube life, etc.
 
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