To the MKI Whisperer...

[FreeFormFunkified]

Has anyone ever modded their mid to late '70s MkI by adding a push-pull treble shift as the later MkII's had?
I dont even know if its possible to do, but that upper mid frequency with just a touch of extra gain in a MKI has been nagging at my imagination for a while. I can hear it in my head just dont know if thats what would get me that sound? Grasshopper patiently awaits your thoughts oh masters of tone!!! :mrgreen:

 

[igfraso]

In the Mark I, the GEQ has very little effect. An easy mod, is to move the GEQ in the circuit and place it after the Master Volume. There it is much more useful and might be of help for you.

 

[FreeFormFunkified]

In the Mark I, the GEQ has very little effect. An easy mod, is to move the GEQ in the circuit and place it after the Master Volume. There it is much more useful and might be of help for you.

I suspect there may be somthing wrong with my eq, when its switched in via the front switch it drops in volume almost in half BUT with twice the gain(another gain boost mode?), and when switched from the input under the chassis it doesnt work at all nor does the gain boost for that matter. There are a a few resistors on the eq
circuit board that dont look right(outsides slipping off the center). How easy is a mod like that to do, is there any info on the board or anywhere else for it?
Thanks Rob

 

[igfraso]

I don't know of any public info available.
I sent it to Mike Bendinelli in Petaluma and that is the only thing he suggested.

 

[FreeFormFunkified]

I don't know of any public info available.
I sent it to Mike Bendinelli in Petaluma and that is the only thing he suggested.

Mike Bendinelli!!! You got friends in high places :wink: Man id like to be a fly on the wall in that shop!
Next best thing is having this board and all the helpful people on here. Mabye someone will chime in with sometning. Many Thanks!

 

[Monsta-Tone]

It would be super easy to add the Pull Boost.
Igfraso is right too, the EQ would be way more useful after the Master.


Where are you located? I would be happy to fix your amp up. Shipping is not bad if you send only the chassis and tubes, not the whole amp.
I've got another Mark I in my shop right now!
My phone is 808 214 five seven four six.
My cell is 808 268 zero three eight four

This is a good time for a little tune up too. New filter caps, clean all pots & jacks, clean and re-tension the tube sockets, etc.

 

[FreeFormFunkified]

It would be super easy to add the Pull Boost.
Igfraso is right too, the EQ would be way more useful after the Master.


Where are you located? I would be happy to fix your amp up. Shipping is not bad if you send only the chassis and tubes, not the whole amp.
I've got another Mark I in my shop right now!
My phone is 808 214 five seven four six.
My cell is 808 268 zero three eight four

This is a good time for a little tune up too. New filter caps, clean all pots & jacks, clean and re-tension the tube sockets, etc.

Hey Monsta-Tone, thanks for the offer but that particular amp has been sent off to mesa for a full service, although I also have a reissue that I would love to do a few things to. I was also following your thread on the "Heartbreaker" sale, that is one one my favorite amps of all and I recently sold mine and deeply regret it, the love channel in boost mode with treble and mids maxed out was just heaven to my ears, but anyway thats for another thread! I definitely will give you a jingle, Thanks

 

[Monsta-Tone]

No worries!

It's 7 AM now. Feel free to call the house phone anytime.
The cell doesn't work at the house.