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Re: Need help on MP 1

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These are some difficult questions to ask, without knowing more about which version you have. There were a few different versions in the early days of the MP-1. If you can give me the serial number, that would probably help. I'm currently upgrading/rebuilding the 7th MP-1 ever made for a fellow ASOG member.

All the early MP-1s can benefit from HexFREDs and pi-filter upgrades to the + and - 225 volt power supplies. The + and - 225 volt regulators can be upgraded to achieve better regulation. The filament regulators and LV supplies do well as is.

The early MP-1s coupling caps were actually quite good, but of course upgrading to the current production Teflon RelCaps can't hurt.

The early phono stages were very different from current production, but they were still good performers. Adding/converting to a CCS in the phono stage is a worthwhile improvement.

The line-stage can also benefit from a CCS and the PCB will support it. There are upgrades to the circlotron output stage's servo that can improve its stability as well.

My all time favorite phono stage tube is still the Mullard military CV4024, which is available from The Parts Connection. They are currently on sale for $8. There are a good many different 12AU7 types that work well in the line-stage. I like the Sylvania 5814, which is a 12AU7 derivitive. A lot of different 6SN7s work well in the circlotron output buffer. Back to the Parts Connection, you can get a NOS Sylvania 6SN7GT, also on sale, for $16.

I hope this helps. You are welcome to send me email directly to discuss many other options as well.


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  • Re: Need help on MP 1 - mark 07:42:01 08/23/01 (0)


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