Marshall 30th Anniversary Series thread (6100 / 6101)

[Mike_LA]

Hey heyyyyyy !!!

New member from France !!

Since yesterday I have the 6101 / Black One / EL34 / G12 Gold …. WONDERFUL

Welcome, you will find a lot of love for the 6100 line here.

 

[Thoma]

...Since yesterday I have the 6101 / Black One / EL34 / G12 Gold …. WONDERFUL
...
In few days I’ll receive the 1x12 6912 Closed Back in 200 watts

Can’t wait.

Congrats!
Spoiler alert:
If you like the 6101 now, you'll love it with the 6912.
The little extension cab really blew my mind when I got mine.
The combination sounds incredibly huge.

 

[rtcook]

Hello. Welcome!

Where did you find the 6912? I'm looking for a blue one.

 Roger

 

[Kuga]

Congrats on your 6101! Great amps! I love my '97 LM6100.

 

[Thoma]

Where did you find the 6912? I'm looking for a blue one.

Cosmetically nice 6912s are rare birds, as those are 30 years old.
22 years ago I lost an ebay bid on two blue ones. I kept bugging the winning bidder for 20 years. Last year he finally sold me one of his blue 6912LEs.
For 20 years I could not find a sound one in Europe.
In the meantime I enjoyed my black 6912.
Good luck finding your blue example!

 

[rtcook]

I have a mint 1912 I am currently using. Would really like the matching blue 6912.

 

[Interstelllla]

Hello. Welcome!

Where did you find the 6912? I'm looking for a blue one.

 Roger

Reverb, from Germany > 570€ / 624$
Seller call it a NOS (and seems brand new).

There s another One from Slovenia but not NOS and semi-closed (can’t post a link until I’ posted 5 posts )

 

[rtcook]

Yes. Seen both of those. They are black. I really want a blue one.

 

[Mentalo]

Hey all, since yesterday I‘m new to the 6100 Club! Never heard of this model before and was eying at a DSL50. But last week a thought „hell I‘ll just give it a try“. Amp arrived yesterday and seems to be okay, never saw any item in my whole life shipped so negligently before. MIDI and everything is working, but at least one tube out of the 4 trashed. So I‘ll get a set of new ones and start biasing that mammoth on the weekend.

 

[Mike_LA]

Welcome to the club.

 

[Jethro Rocker]

Congrats!
Spoiler alert:
If you like the 6101 now, you'll love it with the 6912.
The little extension cab really blew my mind when I got mine.
The combination sounds incredibly huge.View attachment 144136

And makes an awesome little mini stack.

 

[Mentalo]

Sorry, don’t want to spam this thread with pics but damn this amp such a nice piece of Marshall history…

 

[anitoli]

Sorry, don’t want to spam this thread with pics but damn this amp such a nice piece of Marshall history…
View attachment 145666

You can't spam a 6100 thread with a pic of a 6100! All 6100's matter.

 

[Thoma]

All 6100's matter.

Agree.
Blue Amps matter.
Black Amps matter.

 

[Mentalo]

Hey Guys here comes the next challenge on my 6100 journey. Following my plan I equipped the amp with a NOS set of 6P3S-E tubes. I‘m trying to set the bias to proper specs, plate to cathode voltage reads 448V which seems to be in spec. But with the trim pot fully closed I can’t get below 52mA of idle current which seems way to high for my understanding. Do you have any suggestions how to tackle this issue?

Thanks in advance!

Edit:
I’m measuring with a bias probe at V8

R212 is a 33k resistor

 

[Thoma]

As many 5881 Amps have been modded for EL34 and vice versa, I would make sure that the Power Amp is ready for these tubes.
Having tried biasing 6П3С-Е in an 6100LM (original with factory 5881), I succeeded after desoldering the Zener Diode. That was enough to get the required voltage range.

If I remember correctly, my 6100LM Amp (marked for 230V) has significantly higher HT. It's close to 500V @ 240V Mains.
That's why I run it through a Variac.

 

[anitoli]

Hey Guys here comes the next challenge on my 6100 journey. Following my plan I equipped the amp with a NOS set of 6P3S-E tubes. I‘m trying to set the bias to proper specs, plate to cathode voltage reads 448V which seems to be in spec. But with the trim pot fully closed I can’t get below 52mA of idle current which seems way to high for my understanding. Do you have any suggestions how to tackle this issue?

Thanks in advance!

Edit:
I’m measuring with a bias probe at V8

R212 is a 33k resistor

Yes if the zener is in there running 5881's it will clamp the max bias voltage at -51v. 5881 may need a bit more to bias correctly. Also most 5881 schematics show R212 as a 22k, 33k should push it yup higher. Is there a zener in your amp? It would be ZD1 in the bias circuit.

 

[Mentalo]

Yes it’s still in there.

I don’t think that someone messed with it, it had TAD 5881 when I got it. I did some more research on that particular type of tube and it’s real confusing. Some guys tend to use the 6P3S-E really hot, like in the same range that I‘m right now, and they seem to be fine. Still would be nice to have some margin for adjustment.

 

[anitoli]

With standby on ( no sound) measure the voltage swing on pin 5 ( green wire) while rotating the bias pot fuly ccw/cw. Now clip one end of the zener and lift it up a bit so it's positively disconnected and measure again, what is the difference?

 

[Guitaraficionado74]

'92 model 6101, Blue. Love this amp! It has a Jensen C12K replacement speaker. Sounds awesome! I think I like it best as a clean pedal platform.