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Any Members Tried the Audio Interface CST-80 SUT?

My curiosity got the better of me and I just bought this SUT from Japan and wondered if anyone else had any experience with it. The very little I could find seemed to indicate it is a respectable unit and has even been likened to the highly acclaimed Cotter SUT.

It was made in the US around 1982 and came in two varieties. There was a 3 Ohm version with 30dB of gain and a 40 Ohm version with 20dB of gain.

I currently use a Fidelity Research FRT-4 which is excellent and has 4 different taps 100 Ohms, 30 Ohms, 10 Ohms and 3 Ohms + Pass Through for MM.  It will be interesting to see how it compares the FRT-4.

I will use it with my 1.0 mV / 60 Ohms Shinon Boron Red which currently uses the 100 Ohm tap on my FRT-4.

 

ateal
ateal OP
97 posts
 
bimasta, thanks for the great info. Can I ask which version you had, 3 Ohm or 40 Ohm and which selection of carts did you use.

Whilst I initially plan to use it on the Shinon Boron Red first, which seems to be a good match, I will ultimately want to use it with my Spectral Reference which may not be as ideal a match. The Spectral has a low output of 0.2mV and a very low impedance of 2 Ohm. 

I am hoping the low output and low impedance will not be too much of an issue with a quality unit like this. If it is an issue I can just revert back to the FRT-4.

Thanks again for the input.

bimasta's avatar
bimasta
227 posts
 
All I know is the model — CST–80/II H. Maybe that tells you something, but H is a bit ambiguous. After reading your post about 3- and 40-ohm versions, I inserted my ohm-meter probes into the RCA females, but got no readings at all, so I can’t help there either.

I’m searching memory back 20 years as to cartridges I used. It included — Accuphase AC2, VDH MC10, Linn Asak, Coral (aka GAS Sleeping Beauty), Blue Oasis, Audio Technica OC-9, Madrigal Carnegie One, Dynavector 23 Ruby, Ortofon MC20 Super and MC30 Super, Audioquest 909, Fidelity Research MC 201 and FR1Mk3F — that’s all I can recall now.

All sounded lovely, within their own limits. A couple were irritatingly strident in the highs, and I blamed either the cartridge or the CST-80 — but they may have been innocent, I didn’t know much about loading then. It is the mythical “straight wire with gain”, though of course it’s wound wire. (Or possibly wound foil; such a shame so little info is available.)

I mentioned a Thorens/EMT head-amp last time. I like it a lot, it’s dead-silent and has better dynamics when I’m using a passive preamp. But I invariably move back to the CST when using active preamplification, either tube or SS — its transparency and purity is utterly beguiling.

Remember, I’m expecting your review...



ateal OP
97 posts
 
Once again bimasta you have provided some excellent info. Thanks so much for the list of all those cart. 

I think your CST 80 H (high) is the 40 Ohm version like mine as I read elsewhere that the Low version is the 3 Ohm. It’s good to know that it appears very versatile. 

I won’t get mine for at least a week or two as they have not shipped it yet and it’s coming from Japan. But I’ll be sure to post my findings. 




lewm
12,531 posts
 
I've always wondered why manufacturers of SUTs use a resistance/impedance measurement (ohms) as a way of communicating the specifications of their products.  (Not all of them do it, but too many do.)  It's not very informative for the un-initiated.
intactaudio
293 posts
 
When it comes to transformers the two main factors to be designed around are the source and load impedances.  In the case of a SUT the source is a cartridge and the load is the phono stage.  This means that the cartridge impedance is the main factor that comes into play when mating it to a SUT. 

dave
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