Has anyone used the aesthetix calypso preamp?

I was going to invest in a Calypso, but after reading the online documentation that warned against using it with low-impedance amplifiers, I went a different direction.

The MusicalSurroundings.com site quotes the following:

Recommended load is >50K ohms"

Both of my amps at the time, a Pass X-250 and Sim Audio Titan, operate at 20-22Kohms, less then HALF of the reccomendation. So they will work great with SOME amps - not great with others.

Check your amp specs before making any assumptions about compatibility.

BTW - I looked up the input impedance of the Ayre V5x that Bigtee uses and your Plinius SA250. The Ayre's 100k load is 'SAFE' for use with this pre, and your Plinius is 47k.

Though fairly close to the recommended 50k, you MAY experience some minor softening of dynamics and extension when used with the Calypso.

I suggest you contact Musical Surroundings to discuss your particular situation before any purchase.

I was checking in the owners manual and there is actually no statement to the minimum impedance that can be used with this preamp. Bhouser brings up a good point with this. I think, however, that the 50k is refering to a balanced impedance into the amp since the Aesthetix pre is designed to be used for balanced ins and outs. It actually converts a single ended input to a true balanced circuit in the preamp. This would place a single ended impedance at 25k for the amp. (The single ended outs are converted from balanced also) I use the Ayre in balanced configuration which shows a 200k input impedance to the Calypso(100k on each leg.)
I would give Aesthetix a call and ask them.
I used an Audible Illusions L-2 that was rated for no less than a 20k input but Art ferris told me 10k was ok and it did not use a buffer circuit like the Calypso which should make it immune somewhat to impedance mismatches.

I've been waiting two months and may cancel my order. Why start a business if you can't keep up?

Bigtee,

Not to beat the point the death, but-

I totally agree that buyers should qualify with and hold Aesthetix responsible for their statement about 'Recommended load is >50K ohms' on their website. They need to understand that I completely avoided the Calypso BECAUSE of this statement. If one should REALLY cut a specific published impedance value in half, multiply by 2, take the square root or whatever, then manufacturers are only confusing potential customers with such broad-and-simple compatibility statements. Unfortunately, I have read posts on AudioAsylum and AudiogoN from people who have experienced softened or even severely-limited dynamics when using the Calypso with certain amps, so careful system matching MUST be taken very seriously with this pre.

If an output buffer circuit is supposed to make the Calypso 'immune to impedance mismatches', then why would they even feel the need to quote an acceptable impedance load at all? And they mention nothing about the target amp's gain characteristics, which also affects compatibility.

The gain and impedance curves of your Ayre amp are apparently well-matched with this pre, so your experience would obviously be quite positive if the Calypso's other sonic attributes suit your listening preferences.

I decided to go with a tube preamp that has a transformer-coupled output rated to tolerate impedances of as little as 300 OHMS - that's 0.3K Ohms! This characteristic shows up dramatically through BETTER dynamics and impact from this tubed unit then any of the previous Solid-State pre's that I have owned - which is really saying something. Now THAT's true immunity to impedance mismatches to me...

But as usual, YMMV....
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