MARK 1

[domglop78]

Hello
Can someone give me to me a schematic of MARK 1 ( preamp and power amp)
i found some informations but no possibility to read correctly the values of resistors and capacities...
perhaps it will existe a PCB with layout about Mark1 ?(it will be fantastic)

nota: i don't know if the Mark1 have a reverb modul or a Graphic Equalizer modul

Thx for your help
dom

 

[user 21540]

I found this with Google.
https://schematicheaven.net/m-mesaboogie.html

Note that the availability of these probably breaches some sort of copyright. The certified Mesa tech in my part of the world told me he has the schematics for Mesa products but is forbidden to share them with other non-Mesa associated technicians.

 

[mark1406]

Handy circuits

I understand Mesa wants to keep tight lipped about its IP.
However in the case of the Mark 1 the cat is well and truly out of the bag. It amazed me that Mesa do amp mods to their amps. However, I have no idea what services they could offer.

Those are my Mesa observations.

Regards

Mark

 

[user 21540]

Handy circuits

I understand Mesa wants to keep tight lipped about its IP.
However in the case of the Mark 1 the cat is well and truly out of the bag. It amazed me that Mesa do amp mods to their amps. However, I have no idea what services they could offer.

Those are my Mesa observations.

Regards

Mark

Thanks for laughing at me -- appreciate that. Yeah there is only so much they can do. The Tubestore used to have them up but see what its says today:

"Unfortunately we were forced to remove all Mesa Boogie Schematics. Steve Mueller, one of the Managing Directors of Mesa/Boogie Ltd threatened to “aggressively pursue legal remedies” in forcing us to remove this helpful resource."
Source: Mesa Boogie Amp Schematics - www.thetubestore.com

You can however use Wayback Machine with the same URL and find this very same schematics though if you go back to the archived page in about 2016 or 2017.

https://web.archive.org/web/20160228085350/http://www.thetubestore.com/Resources/Mesa-Boogie
The truth is most of them aren't that helpful anyway as they are hand drawn and also portrayed backwards as compared with most guitar amp schematics.

 

[mark1406]

I thought Mesa tried to enforce one of their dodgy patents (the ones that were out of old mags that had no patent on them) on Marshall. I believe Marshall’s response was bring it on and Mesa did the ceasing and desisting.

I think it foolish to consider the Mark 1 intellectual property when it’s a Fender amp with mods. I would bet the mods on Rivera Fender amps are similar. I suppose the Mark 2 was the first Boogie with an original preamp design.

I should point out that I’m not wishing to offend, just saying it how I perceive it.

Regards

Mark

 

[premiumplus]

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[mark1406]

Here is an example of the Mark 1 P.I. stage using the 100 ohm tail resistor and the 820 ohm feedback resistor. I doubt there is a presence control on this amp.

 

[bluebug]

Here is an example of the Mark 1 P.I. stage using the 100 ohm tail resistor and the 820 ohm feedback resistor. I doubt there is a presence control on this amp.

View attachment 68

That's my amp! Yes it does have a presence control, I would like to know why do you mention the presence control?

I noticed your post here so I was going to ask if you can help with my questions on the fetron on my other thread where you probably took the picture, but I just saw you already responded so I'll go continue the conversation there!

Fred

 

[mark1406]

Thanks for your reply, I appreciate that.

Really, the amp has a presence control?

Typically, I don't associate a 100 ohm tail resistor with a P. I. circuit having a presence control.

What is the value of the presence pot?
Typically Boogie’s have a 10K presence pot. The tweed P.I. circuits have a 5K presence pot.

I assume the grid leak resistors are 330K and 1M. I think in my old Mark 1 from years ago had two 330K resistors.

 

[bluebug]

Thanks for your reply, I appreciate that.

Really, the amp has a presence control?

Typically, I don't associate a 100 ohm tail resistor with a P. I. circuit having a presence control.

What is the value of the presence pot?
Typically Boogie’s have a 10K presence pot. The tweed P.I. circuits have a 5K presence pot.

I assume the grid leak resistors are 330K and 1M. I think in my old Mark 1 from years ago had two 330K resistors.

Yes presence control, pic below from my thread (there are a bunch of other ones too). But I'll have to open the amp to check the presence pot value. I can try and find out the grid leak resistors values while in there if you need to know that.

Fred

 

[mark1406]

Judging by the photo I posted if your amp, the presence control is similar to the presence control of the reissue amps. The give away is the 0.001uF cap.