Impedance matching Mcintosh MC2301 and Shindo pre


Dear Audiogon,

This is a problem I wasn't even aware existed until recently! Impedance matching.

Mcintosh website has a downloadable file which quotes the MC2301 tube mono amplifier's "input impedance" as being 47,000 ohms.

I would preferably like to mate this amp with a Shindo pre amp, either the Masseto model, or the Vosne Romanee model. There are several figures available with the word impedance in them, so I didn't know which one to quote for each of the pre amps, so if you could check here
http://www.shindo-laboratory.co.jp/Front/indexe.html
I would greatly appreciate it.

I read that preferably there would be a 15:1 to 20:1 ratio (I think) and all the figures for the Shindo pre amps seemed to be way off that when compared with the MC2301's 47,000 ohms figure, but it's very likely I'm overlooking something here.

So, in terms of impedance matching, can I successfully mate the Mcintosh MC2301 with either the Shindo Vosne Romanee or Shndo Masseto?

Many thanks,

Jake
keysersoze311
Jake...what you need to know is the output impedance of the preamp which are not listed and the rule of thumb is you want a minimum of 10 to 1 (input impedance of amp to output impednace of preamp)and preferably 15 to 1 or 20 to 1. The stats on the website give you the input impedance of the phono modules in the preamp so you know what the load is that the cartidge you are going to be using is going to be seeing with that phono amp. So you still need to find out the output impedance of the linestage portion of the Masseto and the VR. And frankly it's not even that simple, because the output impednace is usually a static measurement at a certain point on the frequency band (usually 1KHz) but the output impedance may vary at different points on the frequency band. So I would try to find out what the max output impednace is for each of those units and use the max number to compare it to the input impedance of the MC2301. If you call the folks at Tone Imports (importers of Shindo) and ask them, they should be able to help you. You can mention to them that you want to pair either unit with the MC2301 and have them advise you as to their impedance matching suitability. And by the way, just because the impedance match may look good on paper, that does not mean the combos will necessarily sound good. So as with all things, there is no substitute to auditioning the units together to see if they are a sonic match that is pleasing to you. Good luck.
10 to one is what you need. The Shindo is 600 ohms out put and the Mac is 47000 input. You should have no problems as you are about 80 to one. Enjoy
Alan
I'm seeing both Shindo preamps display an output impedence of 600 ohms. Doing the math it looks like a 78:1 ratio. Either preamp should work fine.
ooops...missed that. Yep, Jmcgrogan2 is right. From an impedance matching perspective they ought to work. Now you just need to hear them with your MC2301s to make sure they are a sonic match. Good luck.