The Rare Stax CPY/ECP-1 electrostatic phono cartridge & equalizer

I've had this rare piece of TT equipment for almost a year and just now recently set it up. It's a Stax CPY/ECP-1 Electrostatic Phono cartrdige and outboard equalizer. I've done some research on it when I initially got it and found virtually nothing on it except that it is rare and that it was reviewed in The Absolute Sound I believe back around when it was released in the late 70's

Outside of a recent ebay sale that just ended this february, it's hard to guage the value. I think the last Japanese auction ended in the $1800 dollar range. Regardless, I got this as part of a package deal with a nice TT and tonearm and a lot of 200 audiophile Lps, so I didn't pay really anything for it.

What's neat about it is that the original owner is an electrical engineer and designed an outboard power supply for the ECP-1 equalizer so one doesn't have to worry about the battery not working or charging. It works great and sounds nice to my ears, though when doing my research I believe it wasn't reviewed too favorably in TAS.

My question is if anyone has any experience with this setup or if anyone had any thoughts about it in general. It would be nice to hear from others.

I have some included some pics for reference:

I don't have any info on this, but I just sold a Stax CA-Y preamplifier. Also extremely rare and impossible to find info on. I put it up for auction with a buy it now price of $550.00. Audiogons blue book had a new MSRP of $1650.00 and a used price of $165.00 (this is basically all the info I could find after researching it for two weeks...). I started the auction at 10 o'clock in the morning but the listing didn't actually show up until about 4:00 in the afternoon. By 5:00 I had received a ton of emails from all over the world, it had over 20 watchers and sold within the hour. Bottom line is even though you can't find any info on it, make no mistake about it... That thing is highly sought after!!!:yes: Congrats!

wow. Not much to say except it looks cool. How does it sound?

Thanks Elgato. When the original owner was telling me about his TT and mentioned the stax phono cartridge, I was surprised since I had no idea stax made an actual cartridge.

Jgordon - It sounds fantastic. Smooth and warm if that makes any sense. It was designed so that MM/MC stages were not needed so you just plugged the output of the equalizer directly into the AUX input of your preamp.

Oooooh, that looks nice! :thmbsp: I think you did extremely well with that pick-up [pun ntended ]. Even if someone''s review wasn't glowing [Heck, half the reviews are thinly-disguised advertising, anyway], it's an interesting, rare and attractive piece of technology from a highly-regarded manufacturer. Can't be too bad, can it?!

What is the linear-tracking table you have it mounted on? I'm becoming more interested in linear trackers lately, and bought my first one just yesterday (a Pioneer PL-L1 Japan-market model), which I'll bring home on Saturday. Really looking forward to playing it! Any comments/suggestions for using LT TTs?

Arkay said:

Oooooh, that looks nice! :thmbsp: I think you did extremely well with that pick-up [pun ntended ]. Even if someone''s review wasn't glowing [Heck, half the reviews are thinly-disguised advertising, anyway], it's an interesting, rare and attractive piece of technology from a highly-regarded manufacturer. Can't be too bad, can it?!

What is the linear-tracking table you have it mounted on? I'm becoming more interested in linear trackers lately, and bought my first one just yesterday (a Pioneer PL-L1 Japan-market model), which I'll bring home on Saturday. Really looking forward to playing it! Any comments/suggestions for using LT TTs?

Click to expand...

Thanks It does sound nice so I have no complaints. It's actually mounted on an older Souther (aka Clearaudio) Linear Tonearm. I can't remember the model off hand. The Table itself is a VPI. I love the tonearm but I may possibly upgrade the table itself to something a bit more substantial.

I bet your excited about the PL-L1. I would be. That table is uber rare. Good job finding one and hope to see some pics of it.

Want to swap documentation?

Hi Rhiohki,

I have the STAX ECP-1/CPY set-up too, I bought it about a year ago from a laboratory in Paris, France. The sounds that I got out of it were very promissing, but there is a strong channel inbalance which makes it impossible to really use it. And it can't be properly compensated with the adjustment potmeter, unfortunately. I think I need to do some work on the equalizer unit to get it working right. On your picture, it seems that you have the schematics to this unit, so that would be of great help for me. In return, I could send you the patent that describes in detail how these cartridges work anyway. Are you interested? Thanks in advance for your reply!

nieuwekunst

Somebody just posted a thread recently about his late 60s Toshiba, I think, turntable with a switch for magnetic/condenser cartridge. And we discovered that Stax was the developer of that cartridge. Quite a coincidence that this thread would pop up.

hakaplan said:

Somebody just posted a thread recently about his late 60s Toshiba, I think, turntable with a switch for magnetic/condenser cartridge. And we discovered that Stax was the developer of that cartridge. Quite a coincidence that this thread would pop up.

Click to expand...

Interesting. This thread was actually created a while ago. I only know, in my research, Stax to have mad two types of these carts. The one that I have and another version. Do you know the model of the cart by any chance? It's always nice to hear from other stax cartridge owners.

hakaplan said:

Somebody just posted a thread recently about his late 60s Toshiba, I think, turntable with a switch for magnetic/condenser cartridge. And we discovered that Stax was the developer of that cartridge. Quite a coincidence that this thread would pop up.

Click to expand...

Yeah, that was me. I have a mid 70's Toshiba TT that is set up to play either Magnetic or Condenser. Toshiba had developed one during that time frame. I'm keeping my eye out for one myself!

Here is some informations about this stax setup

I also have a CP-y and the ECP-1 which I plan to use in the future.

I have to make the ECP-1 retipping and change the batteries in the CP-y.

Where can I find a new stylus or can do retipping ?

Many years ago, someone (Mr. Russ Sherwood) gave me some recommendations about this Stax pair. Here is the informations I want to share with you. I tried to contact him again but his email isn't good now.



Hi Marc,

Curious to meet you this way. In my not so humble opinion, there are only
phono cartridges that sound worse than the Stax CP-Y- none better. If you
need retipping, I can find that address for you but it will take a bit.
(they will retip and cartridge) The cartridge body has two Toshiba self
bias J-FET inside, one for each channel. In short- they are crap. I
replace these with a Panasonic part # FET-1. These are widely available by
removal from inexpensive ($2) electret microphone- even at Radio Shack but
I would use one from Digi-Key to be certain it is not a low quality one.
Hooks up just like the Toshiba except the panasonic goes gate drain source
and the toshiba goes drain gate source on the leads ( believe this is
correct). Because the bandwidth of the CP-Y limited on the low end by the
tone arm resonance frequency (should be 2Hz-3Hz) and on the top by the
transistor capacitance (100kHz-150kHz) the Stax phono pre is not really up
to the task of all that bandwidth. So I get bandwidth 2Hz-100kHz +-0.5dB
every time when I use a home brew phono stage for it. EQ is for a
displacement transducer rather than a velocity transducer. At the standard
groove level on a vinyl record- signal to noise is about 80dB- which is
10dB better than anything I have ever achieved with magnetic cartridge
(69dB). This means my system is very quiet until the tip touches the
record. I suppose (really certain) the Stax ECP-1 could be tuned up to
sound much better but I have never tried. Simple op-amp circuits or easy
J-Fet circuits do the job nicely.

As far as the short answer, a balance or channel level control added to the
ECP-1 can serve to balance out the failings of the Toshiba part. A 10uF 10
volt solid tantulum capacitor should be added between the left and right
ground at the cartridge. I solder this directly to the cartridge- mind the
polarity as the grounds are the power for the transistor- and then install
into the tone arm. As I say, never tried to fix the ECP-1 but am certain
it would be easy and obvious what to do for me these days.

As for value, these are as far as I know made of unobtainium, I bought
quite a few to have stock for the rest of my life. Most people do not want
to use them because of two main reasons. The channel balance- which you
know about and is of little concern to a person with a level control on the
ECP-1 and the wide bandwidth which can drive poor equipment into
horrendously horrible distortion which really sounds bad. So the value is
what a buyer will pay. I bought several more in 1995 and paid about $150
for each.

For me, I desire extreme amounts of clarity without a trace of harshness,
grittiness, or scratchy sound. The Stax provides more of this than any
other. Add to that its nominal tracking of about 1 gram and you end up
with long vinyl life and fantastic sound though you will have to jump
through a few hoops to get there.

Hope this helps and good luck,

Russ Sherwood

nieuwekunst said:

Hi Rhiohki,

I have the STAX ECP-1/CPY set-up too, I bought it about a year ago from a laboratory in Paris, France. The sounds that I got out of it were very promissing, but there is a strong channel inbalance which makes it impossible to really use it. And it can't be properly compensated with the adjustment potmeter, unfortunately. I think I need to do some work on the equalizer unit to get it working right. On your picture, it seems that you have the schematics to this unit, so that would be of great help for me. In return, I could send you the patent that describes in detail how these cartridges work anyway. Are you interested? Thanks in advance for your reply!

nieuwekunst

Click to expand...

I owned one of these in the mid-80ties. I experienced exactly the same problem as you: A strong channel imbalance not really possible to compensate for. I gave it up and sold it rather cheap.
But to the story there is a very positive part, and that is the Stax system provided me with the smoothest sound I ever have heard from any source. (OK, it is 20 - 25 years ago....)

If someone would like to publish patents and schematics (as mentioned elsewhere, I would appreciate that very much. (Or just drop me an email.)

Best regards
Rolv-Karsten Rønningstad

legarem said:

I also have a CP-y and the ECP-1 which I plan to use in the future.

---
Curious to meet you this way. In my not so humble opinion, there are only
phono cartridges that sound worse than the Stax CP-Y- none better. If you
need retipping, I can find that address for you but it will take a bit.
(they will retip and cartridge) The cartridge body has two Toshiba self
bias J-FET inside, one for each channel. In short- they are crap. I
replace these with a Panasonic part # FET-1. These are widely available by
removal from inexpensive ($2) electret microphone- even at Radio Shack but
I would use one from Digi-Key to be certain it is not a low quality one.
Hooks up just like the Toshiba except the panasonic goes gate drain source
and the toshiba goes drain gate source on the leads ( believe this is
correct). Because the bandwidth of the CP-Y limited on the low end by the
tone arm resonance frequency (should be 2Hz-3Hz) and on the top by the
transistor capacitance (100kHz-150kHz) the Stax phono pre is not really up
to the task of all that bandwidth. So I get bandwidth 2Hz-100kHz +-0.5dB
every time when I use a home brew phono stage for it. EQ is for a
displacement transducer rather than a velocity transducer. At the standard
groove level on a vinyl record- signal to noise is about 80dB- which is
10dB better than anything I have ever achieved with magnetic cartridge
(69dB). This means my system is very quiet until the tip touches the
record. I suppose (really certain) the Stax ECP-1 could be tuned up to
sound much better but I have never tried. Simple op-amp circuits or easy
J-Fet circuits do the job nicely.

Russ Sherwood

Click to expand...

So the inside of the Stax cartridge is something like a good old electret conedenser microphone, like the attached figure?

Rolv-Karsten

Stax CP-Y and ECP-1 in use

Dear all,

The thread I am replying to is rather old...

For who is interested. I have the STAX CP-Y cartridge and the preamplifier ECP-1 in use after replacement of the NiCD-batteries.

Both cartridge and amplifier were never used....

And now about the sound;
Very decent, absolute not that dynamic but sweet. Bass reproduction is a little behind.

I observed the output level to the line input is rather low.
I need to turn up the volume control more than compared to the position of it needed while listening to other sources.

The cartidge has been mount onto a SME 3009 SIII arm. The turntable is a Thorens TD150 from which I modified the arm board.

The preamp is an Accuphase C280V. Power Amp is an Accuphase P800. Speakers are from B&W, model 802 matrix SIII.

I hope I can find more information about the ECP-1 preamp such as a schematic diagram.

Kind regards,

Gert van Wee

Have a look here http://www.diyaudio.com/forums/analogue-source/208935-adding-gain-phonostage.html
I think this is correct.

Rolv-Karsten said:

Have a look here http://www.diyaudio.com/forums/analogue-source/208935-adding-gain-phonostage.html
I think this is correct.

Click to expand...

Hi Rolv-Karsten,

thank you for your reply.

The low output level is correct (confirmed).

It is not easy to get extra amplification by changing the design.

A simple additional line amplifier would be the solution but might imnpair the sound quality.

I guess it is better to turn up the volume to the required level.

Does anyone else has experience with this STAX cartridge and the accompanying preamplifier?

Kind regards,

Gert

I am pretty sure one could do better than the Stax electronics. A good stage with e.g. 2SK170/2SJ74 at the input and with e.g. +/-15VDC power supply could be better in my humble opinion. I have some Borbely line amp PCBs I plan to modify. Remember to bias the CP-Y with 9.6VDC to the right RCA jack's screen and GND to the left screen.
With a good power supply I doubt that the battery approach is necessary.
To all this i have read that the JFETs inside the CP-Y are crappy - fading with age. So it might be a major project to change these. Removing epoxy etc etc.