Ah, I was under the impression the Signal Transfer Company was solely a Gareth Conner operation (remote from yourself) and a 3rd party supplier/manufacturer you approved of for PCB's that were approved by yourself.
Perhaps that is because those two names always went together and maybe its an historic connection I'm remembering from E&WW days.
So all good then.
Edit... and yet anyone searching for 'Signal Transfer Company' will find this which I assume is not run by yourself:
Edit edit... but it finally links back to your site.
The Signal Transfer Company ▷ Mytholmroyd, Unit 9A, Topland Country Business Park, Cragg Road
Douglas I think what Mooly is saying is that the Signal Transfer Company name is now associated with poor service. However it's up to you whether or not you think it's worth a name change.
Additionally - there is an error on the site - a random "x" has found it's way into the top banner - in this part of the code:
Code:
<IMG SRC="stripest.gif">x
<P>I feel it would also be useful to enlarge (and embolden) the text about Gareth and the poor service provided in order to draw attention to it.
The entire site could probably benefit from a facelift to be brutally frank!
Sent email @ 1540 Greenwich time on Monday 30 Aug. Want to buy 4 PCBs and pay shipping. I sent to the xxxxxxxxxx7@gmail.com address.
Dear mr. Self,
not being particulary skilled in the art of designig PCBs using computers, I'd like to buy some PCBs for a trimodal load invariant class G. A hell of a machine, IIRC. Could this wish become true?
Thank you.
Signal Transfer Company
I recently purchased the balanced output RIAA PCB from Douglas Self and am most impressed with the quality of the PCB. Unfortunately I then discovered that the 2SB737 transistor is no longer manufactured and virtually unavailable now, so I bought some ZTX 951s as one of the alternatives suggested earlier in this thread. To my surprise I then actually found a few companies in the USA and one in Republic of Ireland who claim to have access to a supply of the 2SB737 (Dönberg Electronics - Electronic Components and Equipment) so out of curiosity I ordered some from Donberg and they arrived today. I am however aware that fake 2SB737 are available from sources like ebay - so my question is, is there an easy way of telling if the 2SB737 transistors I've bought are genuine items or substandard fakes with inferior performance? When I say easy I mean other than soldering them in to the above PCB and listening to the result. Fake ones are I believe very noisy. I've tested the hFE of the 2SB737s I've bought and they're all around 210.
I recently purchased the balanced output RIAA PCB from Douglas Self and am most impressed with the quality of the PCB. Unfortunately I then discovered that the 2SB737 transistor is no longer manufactured and virtually unavailable now, so I bought some ZTX 951s as one of the alternatives suggested earlier in this thread. To my surprise I then actually found a few companies in the USA and one in Republic of Ireland who claim to have access to a supply of the 2SB737 (Dönberg Electronics - Electronic Components and Equipment) so out of curiosity I ordered some from Donberg and they arrived today. I am however aware that fake 2SB737 are available from sources like ebay - so my question is, is there an easy way of telling if the 2SB737 transistors I've bought are genuine items or substandard fakes with inferior performance? When I say easy I mean other than soldering them in to the above PCB and listening to the result. Fake ones are I believe very noisy. I've tested the hFE of the 2SB737s I've bought and they're all around 210.
Compare the appearance with an original. These appear to be genuine.
https://www.ebay.com/p/662320799
https://www.ebay.com/p/662320799
I have 2SB737 in stock. Low Noise Transistors from Zetex and ROHM
These are from John Roberts' original inventory for the MC version of his 1980's Popular Electronics preamp.
FWIW the ZTX951 will be a little quieter: Low Noise Transistors: Comparing the ZTX1053A and ZDT1053 (Dual) vs. the ZTX689B and ZTX851 - Page 2 - Pro Audio Design Forum
These are from John Roberts' original inventory for the MC version of his 1980's Popular Electronics preamp.
FWIW the ZTX951 will be a little quieter: Low Noise Transistors: Comparing the ZTX1053A and ZDT1053 (Dual) vs. the ZTX689B and ZTX851 - Page 2 - Pro Audio Design Forum
The KSA992 is about 3nV/√Hz from some of my measurements, the 2SB737 is according to datasheet about 0.55nV/√Hz. So no, not a good substitute.
The ZTX951 is a PNP that has even lower voltage noise than the 2SB737, its complementary to the ZTX851.
But voltage noise isn't everything (often its not very relevant and current noise is more relevant - I don't have data on current noise for either of these).
Put crudely voltage noise matters for MC inputs, current noise for most MM inputs (due to the high impedance).
The ZTX951 is a PNP that has even lower voltage noise than the 2SB737, its complementary to the ZTX851.
But voltage noise isn't everything (often its not very relevant and current noise is more relevant - I don't have data on current noise for either of these).
Put crudely voltage noise matters for MC inputs, current noise for most MM inputs (due to the high impedance).
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By kind permission of Mooly and the other mods, I am making a one-off post to update everyone on the status of the Signal Transfer Company.
It took a little while to arrange, but most of the ST PCBs are now in stock. The quality is the same, with gold finish.
Specifically:
Trimodal power amp PCB002
Load Invariant amp PCB004
RIAA preamp unbal out PCB006
RIAA preamp bal out PCB007
Protection card PCB008
Compact Class-B amp PCB009
Low-noise balanced input PCB0012
Power amp PSU PCB0014
The Devinyliser PCB0017
One PCB I have not re-stocked is the MRP11 Precision Preamp PCB003. I have only had three enquiries this year
and they are expensive to manufacture. If you want a Precision Preamp do let me know and I will reconsider this.
Likewise for the Class-G PCB005; if people want to buy a decent number, I should be now able to get more made in a couple of weeks
I have also decided to sell some of my lifetime stock of genuine 2SB737's bought from Rohm some 15 years ago. I know there are many fakes but these are the real thing. The price is £10:00 each. Each device is tested for basic operation and beta before dispatch, and I am buiding a test rig to confirm noise performance.
Since I took over the affairs of Signal Transfer in May this year I have fulfilled 51 orders promptly, and more are being processed.
Please place orders by email. I do not look at this forum very often. I now accept PayPal as well as direct bank transfer.
In order to save the planet the Construction Notes will be sent in electronic form (PDFs) when the current paper stock is exhausted.
The Signal Transfer website is at http://www.signaltransfer.freeuk.com/
It took a little while to arrange, but most of the ST PCBs are now in stock. The quality is the same, with gold finish.
Specifically:
Trimodal power amp PCB002
Load Invariant amp PCB004
RIAA preamp unbal out PCB006
RIAA preamp bal out PCB007
Protection card PCB008
Compact Class-B amp PCB009
Low-noise balanced input PCB0012
Power amp PSU PCB0014
The Devinyliser PCB0017
One PCB I have not re-stocked is the MRP11 Precision Preamp PCB003. I have only had three enquiries this year
and they are expensive to manufacture. If you want a Precision Preamp do let me know and I will reconsider this.
Likewise for the Class-G PCB005; if people want to buy a decent number, I should be now able to get more made in a couple of weeks
I have also decided to sell some of my lifetime stock of genuine 2SB737's bought from Rohm some 15 years ago. I know there are many fakes but these are the real thing. The price is £10:00 each. Each device is tested for basic operation and beta before dispatch, and I am buiding a test rig to confirm noise performance.
Since I took over the affairs of Signal Transfer in May this year I have fulfilled 51 orders promptly, and more are being processed.
Please place orders by email. I do not look at this forum very often. I now accept PayPal as well as direct bank transfer.
In order to save the planet the Construction Notes will be sent in electronic form (PDFs) when the current paper stock is exhausted.
The Signal Transfer website is at http://www.signaltransfer.freeuk.com/
Thanks! This part has the correct pitch, but doesn't have the build-in LEDs like the original switches that were used on the board. Is there a source for those switches? Or, can I just use any LED there? I ask, because I may just mount the LED on the case panel. Is the LED necessary for operation of the circuit, or should I just leave it open?
How about the RCA jacks? many thanks!!
sure thing! I replied to your post on the DS preamp thread too…. I bought the RCA jacks at Newark. Search for 26M2040. Newark is out of the white ones, so just use two of the red ones and change the color of one using a marker.