Advent MPR-1 mic pre

[k brown]

I'd love to get a knowledgeable person's take on this circuit; the MPR-1 was an accessory sold for the Advent cassette deck (I believe the first w/Dolby), to provide mic inputs for the set of Beyer dynamics that they also sold rebranded Advent.

It appears to be a bit more sophisticated than the usual 'ring of three' - Expected performance? Ideas for improvement? I modded mine for transformerless inputs (the stock ones are quite tiny), and three-position gain sw - but would love to know if more could be gotten out of it.

Thanks

 

[k brown]

Wow - no interest in this at all.

 

[musipol]

The design looks opamp-like with global FB( with a sw. to adj gain). Looks like they were biasing the input TIS97's with current in parallel thru the 100k and the xfmr sec. DC current thru the transformer doesn't seem like a great idea. Why is it you are so interested in this? Is the sound something special? It looks pretty ordinary to me.

 

[k brown]

It's just that i have a couple of them and would like to put them to good use. I'm using it without the transformers, and it sounds more transparent than op-amp based ones I've compared it to. Was just curious if it looked unusual to anyone, and if any improvements/optimizations would be suggested.

Thanks for taking a look.

 

[Turnbuckle]

It's just that i have a couple of them and would like to put them to good use. I'm using it without the transformers, and it sounds more transparent than op-amp based ones I've compared it to. Was just curious if it looked unusual to anyone, and if any improvements/optimizations would be suggested.

Thanks for taking a look.

This thread is pretty cold but I wanted to ask what opinion you arrived at regarding the MPR-1? I need a mic amp to boost the signal on a Shure M66 passive SUT based broadcast phono preamp. It outputs at Mic rather than line level. Having used and enjoyed passive preamps and given that the M66 cost more than twice the cost of the M65 (their tube phono pre) at the time of manufacture, I thought I’d roll the dice. I didn’t expect the gain issues however. The Advent MPR-1 is a lot simpler than pro units and uses RCA and Phono jacks rather than XLR. Any input is greatly appreciated.

 

[k brown]

This thread is pretty cold but I wanted to ask what opinion you arrived at regarding the MPR-1? I need a mic amp to boost the signal on a Shure M66 passive SUT based broadcast phono preamp. It outputs at Mic rather than line level. Having used and enjoyed passive preamps and given that the M66 cost more than twice the cost of the M65 (their tube phono pre) at the time of manufacture, I thought I’d roll the dice. I didn’t expect the gain issues however. The Advent MPR-1 is a lot simpler than pro units and uses RCA and Phono jacks rather than XLR. Any input is greatly appreciated.

Pretty neutral sounding, if a bit on the 'dry' and 'hard' side.

 

[Turnbuckle]

Did you recap it? After 50+ years, might be past it’s prime.

 

[k brown]

Did you recap it? After 50+ years, might be past it’s prime.

Yes; was the first thing I did.

 

[Turnbuckle]

Well that gives me a good sense of what to expect. Thanks again.