Mystery preamp

[Frank]

Just wondering if any of you good people know anything about the mysterious device in the middle of the rack, the ACT MP-1000 MIDI valve preamp. I've had this for more than 15 years now, got it from a shop in Newcastle in my student days and the entire internet seems to have zero information on who made it. I'm guessing it was a prototype unit for something that never went into full production as the panel printing doesn't properly line up with the LED display. It sounds utterly wonderful, tight compressed Fendery/Voxy tones and the best crunchy overdrive ever but I've got absolutely no idea of its history.

[FELINEGUITARS]

I've seen the ACT preamps before - they date from about 1987/88
They were a pretty good preamp , but got swallowed up the the tidal wave of excitement that the ADA MP1 created

Last time I saw one was in a music shop I worked out of in Surbiton
There were a few about but nowhere near the numbers of the ADA unit

Dont have any history on them though but if it works well for you hang onto it!

[Philly Q]

I thought Jonathan would be the man to answer this!  :D

[FELINEGUITARS]

BTW - is the Quadraverb in a parallel loop to the main preamp?

If not try plugging your preamp directly into the power amp for a bit
You may get a shock at how much tone, volume and dynamics the Alesis is sucking out of the signal

I discovered this when a Quadraverb I had went wrong and I had to send it off for repair
Once I plugged in directly I was blown away - and subsequently used a rack mixer to send most of my signal direct from the preamp top the power amp and tapped off just a bit to go through the effects unit and mixed it back in with the main signal - was tons better

I used a TOA D3 line mixer , but there are others available

[Frank]

BTW - is the Quadraverb in a parallel loop to the main preamp?

The mystery preamp has a programmable FX loop so 90% of the time the Alesis is bypassed and it's just guitar >> preamp >> power amp. I'm not having all that lovely valve tone messed up by digital tomfoolery! Just the odd song uses tempo-matched delay, otherwise I'd live without effects altogether.

[Frank]

I've seen the ACT preamps before - they date from about 1987/88
They were a pretty good preamp , but got swallowed up the the tidal wave of excitement that the ADA MP1 created

Last time I saw one was in a music shop I worked out of in Surbiton
There were a few about but nowhere near the numbers of the ADA unit

Dont have any history on them though but if it works well for you hang onto it!

I never really liked the ADA preamp, just sounded too mushy and weak for me. I'm hanging on to the ACT until it totally dies, can't live without it. And if it totally gives up the ghost then I'll pull the valve circuitboard out, clone it and build a simple three-channel version for myself. If I could find a circuit diagram I'd probably do this right now and mothball the ACT before it dies. Maybe time to open it up and trace the circuit myself!

[webweave]

I have some info on the ACT MP-100 preamp. I have one and a buddy of mine has three, we are keeping them going and have helped others keep them running.

The MP-100 was designed by William (Bill) Hannapel he also owned the company that produced them ACT (Analog Control Technology of Kalamazoo, MI.) Mr. Hannapel's name pops under a number of searches as a guitar player in a couple of bands and as a studio artists and he seems to have some relationship to Heritage Guitar Inc., also of Kalamazoo.

I have seen a photo of another preamp like the MP-100 which seemed by the description to have a motorized fader. I don't have the photo but I'm looking for it.

There is a story (unconfirmed) that ACT was sold to Halfer and was re-branded and sold for a while.
 
Cheers,
Brian

(Photo: William (Bill) Hannapel in his studio, notice the MP-100 on the rack.)

We have had much luck keeping these units running, they are very well built and easily modified.

[Frank]

Thanks for that, I knew if I waited long enough then someone would come forward with some info! My MP-100 is still in daily use and still giving good service after 23 years. Having said that, if anyone has formed any kind of support group to keep this wonderful piece of technology running then that's very useful information for me. Thanks again for the info!

[webweave]

I'm glad you like it. How is the battery in your unit? I've replaced batteries in all our units, you can't find the exact one but the replacements listed in the catalogs do work. Hell its only a plus and a minus no matter how many pins the things have. I actually put extended wires to the pcb and glued the battery to the cabinet to make the next change easier. That's how much I like them.

Do you have the manual? I have a pdf copy if you need it.

[Frank]

No problems with the battery here but it's only a matter of time I suppose. And yes, a PDF of the manual would be greatly appreciated as would any schematics in case I have to dig in there sometime!

[webweave]

How have you've been programming it without a manual? A cheat sheet?

I don't have a schematic, you now have all I have. the circuit is pretty simple to understand if you know TTL/6502 which is most of the board. The analog section is less than a quarter of the pcb and right around the tube.

If you do need to change the battery do it from the top, removing the board from the chassis is a major pain.
Here's a modern replacement part that works. NIC2510 3.6V  60mAh NiCd   Interstate Batteries.

[Frank]

Programming wasn't too difficult to figure out. I even managed to dump the memory into a WAV file and figure out hte MIDI program change, just through trial and error. Many thanks for the PDF, that's already told me how to revert edited patches if I accidentally overwrite them.

[webweave]

Glad you got something out of it.

Did you ever happen to get an editor or librarian working with your ACT?

[Frank]

Never tried any librarian software with it, I just assumend it didn't support SYSEX over MIDI so I'm putting my faith in the audio file for data backup.

In the event of dire emergency I've got the individual parameter numbers saved in a spreadsheet!

[studio714]

i have recently come to own one of  these - seems the battery is dead as it holds  no data changes and I hav no idea  how to profram it nor can I find manuals any help wold be greatly appreciated !