Ohm Walsh Micro Talls: who's actually heard 'em?

Juicy Music BLueberry: output impedance 3.5K ohms, not as low as the Manley perhaps but will cost less (Juicy may be in process of closing up shop however)

FWIW my ARC sp16 output impedance is ~20K ohm and the input impedance of my A3CR amp is just over 30K ohm.

Input impedance of new BElCanto Ref 1000m Class D amps is over 300K I read.

Wyred 4 Sound Class Ds are 60K ohm I read.

Also, stock IcePower Class Ds are only 5K or so I think I read, not a great match for just any tube pre-amp.

Juicy Music Blueberry Line Stage specs:

* Gain:16dB
* Frequency Response:-3dB 2Hz - 40kHz
* Hum and Noise:85dB
* THD:0.2% 20Hz - 20kHz ref. 2V out
* Max Output:40Vrms into 47k ohms
* Input Impedance:100k ohms
* Output impedance:3.5k ohms

Spoke to Matt at Bel Canto today. He says that what's called for is a preamp with an impedance output of between 50 and 100 ohms

- shrink and center the quoted text

Rebbi, there are a limited number of tube preamps avaiable that will fall in the 50-100 output impedance range but if a Bel Canto rep says it, then its advisable to stick with that. I'd steer clear of preamps with output impedance in the thousands if I were you. The Juicy Music preamps do have variable output impedance that can be swithced to low output impedance.

If you don't need a phono section, the Juicy Music Peach I (or II) has a selectable output impedance with a low Z option of 50 ohms. It's a heck of a preamp if you can be patient and fine one used.

IMO, the 3.5k Ohm output impedance of the Blueberry is too high to match with most solid state amps because of the risk of rolled off bass.

Rebbe,

YEs, the Peach is the one without phono and apparently lower possible output impedance also, so that would be the Juicy Music one for you to consider.

Tvad,

I know you've heard a lot of combos and have a good handle on the matching impedance issue between amp and pre.

Do you find that the ratio of amp input to pre-amp output impedance is a reliable indicator of performance? If so, what differences do you hear consistently as this varies? Are there thresholds regarding this ration that can be identified that reliably predict actual performance in certain areas?

Thanks for whatever insight you might offer up on this topic.