Another Super High End Phono Stage! No expense spared...
- Thread starter Fasterdamnit
- Start date
sxty8goats
Super Member
It may even be cart dependent. A few weeks ago I went to a small AK event here in MA. I pulled my cart, M91ED/SAS, and brought it w/ a few others to the event in case anyone there wanted to hear them.
A couple days later I re-installed the cart. HUM, bad hum. I didn't do anything else to the 2 channel system beyond pulling the cart a couple days before and re-installing it. So my first thought wasn't a ground issue, it was cart issue. To test that, I grabbed another headshell loaded with an M97ex. No HUM. Crap, my favorite cart is shot.
I look around for a week or so and found a replacement M91ed body. Got it home, mounted it to another headshell. HUM. Both M91's HUM. M97ex, still no hum. WTF? Knowing I hadn't touched the 2 channel set up but reaching for straws I decided to check the ground. (Lots of in between left out here..
). Sure enough, the ground wire from the TT was not attached to the receiver. The 2 channel set up is on the same shelf as the 7.1 channel set up. I had done work to that, adding a media server. I must have tugged a wire that tugged the ground off of the post. M97ex doesn't hum w/ no ground M91ed does. (M97ex hums with no ground and no stylus)
Finally I built a very nice twin mono phonostage
by myself, its a 1963 professional broadcast cirquit-Design
(BY RIM RADIO COMPANY MUNICH) using 4 selected European type
low noise Germanium Transistors per channel (8 in total for Stereo)
for voltage I built an external twin Mono Sulzer Borbely regulator.
The sound of this NBV (newly built vintage) -phonostage is breathtaking clean, crisp, deep in stage, smooth on voices and sax...
Listening to Diana Krall with this RIAA System is a pure pleasue.)
you will need pretty expensive boutique stuff (maybe with tubes) to do it clearly "better".
Gain is not too high so best use slightly higher output MM system.
Thats the Phonostage for one Channel using only the finest vintage components
(discretly built like an old tube amp with point to point wiring instead of a cirquitboard )
For coupling and decoupling I used finest russian 400 Volts paper in oil mil spec tin sealed caps and german made
"Beyschlag" carbon low noise resistors from the 60s and 70s. (Selceted by hand to closest tolerances)
I really wanted that original sound of the 60s out of these RIAA fuzzboxes
Twin Mono sulzer-Borbely voltage Regulator for ultra quite 24 Volts DC
Regulator case
Transformer and rectifier box using 4 discrete
ultra fast - lowest drop "Schottky Diodes" per Channel
(Whole Rectifier also dual Mono)
First filterstage CRC using a horde of small 220uF (fast) capacitors instead of
giantly oversized caps...so alltogether +- 2000 uF per Channel is widely enough for only 4 small
signal transistors per Channel....no need for 20.000uf giant cap stuff here...
works, no hum, no noise ready for installation
(The black transformerbox finally also got its cover - after a week staying open for voltage and heat checking...)
Best regards from Germany
Willy
by myself, its a 1963 professional broadcast cirquit-Design
(BY RIM RADIO COMPANY MUNICH) using 4 selected European type
low noise Germanium Transistors per channel (8 in total for Stereo)
for voltage I built an external twin Mono Sulzer Borbely regulator.
The sound of this NBV (newly built vintage) -phonostage is breathtaking clean, crisp, deep in stage, smooth on voices and sax...
Listening to Diana Krall with this RIAA System is a pure pleasue.)
you will need pretty expensive boutique stuff (maybe with tubes) to do it clearly "better".
Gain is not too high so best use slightly higher output MM system.
Thats the Phonostage for one Channel using only the finest vintage components
(discretly built like an old tube amp with point to point wiring instead of a cirquitboard )
For coupling and decoupling I used finest russian 400 Volts paper in oil mil spec tin sealed caps and german made
"Beyschlag" carbon low noise resistors from the 60s and 70s. (Selceted by hand to closest tolerances)
I really wanted that original sound of the 60s out of these RIAA fuzzboxes
Twin Mono sulzer-Borbely voltage Regulator for ultra quite 24 Volts DC
Regulator case
Transformer and rectifier box using 4 discrete
ultra fast - lowest drop "Schottky Diodes" per Channel
(Whole Rectifier also dual Mono)
First filterstage CRC using a horde of small 220uF (fast) capacitors instead of
giantly oversized caps...so alltogether +- 2000 uF per Channel is widely enough for only 4 small
signal transistors per Channel....no need for 20.000uf giant cap stuff here...
works, no hum, no noise
ready for installation (The black transformerbox finally also got its cover - after a week staying open for voltage and heat checking...)
Best regards from Germany
Willy
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Wow! That is nice work. I'm surprised that you could find the proper semiconductors for a 1963 design. I would have expected them to be out of manufacture for several decades.
I see two monophonic boxes for the amplification and RIAA EQ, one box has transformers, rectifiers and a lot of capacitors, what is the third box, second from the right in the last picture? Is that power supply regulation?
And a final question, how do you tell input from output on the right and left channel amps? I would swear that both ends look identical.
I see two monophonic boxes for the amplification and RIAA EQ, one box has transformers, rectifiers and a lot of capacitors, what is the third box, second from the right in the last picture? Is that power supply regulation?
And a final question, how do you tell input from output on the right and left channel amps? I would swear that both ends look identical.
Hi,
thanks for the flowers
the mid box (the silver larger one ) is the adjustable Sulzer - Borbely "TANDEM" Regulator.
it also has an integrated active ANTI HUM device if there should remain any rest of hum coming out of the sulzer reg, it terminates even that (so I can be pretty sure that the 24 Volts DC coming out of that monstrous regulator are quite as a vacuum,
quite as the best battery setup or even quiter...)
The Regulatorbox has a twisted lock "2x Unregulated 35V DC Power In" jack (coming from the transformer, rectifier box),
outcoming ultra quitely regulated twin 24V DC go through japanese TAYMIA RC car loading jacks and cables right to the both RIAA Phonostages.
it does not matter wich power cord from there goes to the left RIAA and right RIAA "Fuzzbox"...
Those RIAA "Fuzzboxes" have TAYMIA power in jack and two RCA tone jacks.
The INPUT JACK is on the side of the power input jack the outcoming is on the other side...so its easy to distinguish.
One might install a FEMALE / MALE RCA Plug system but I dont need it.
The OC and AC Germanium Transistors you can easily get from ITT and Valvo/Philips brand
on ebay germany new old stock or you can "rip out" old transistor scrap radios.
I got mine matched from a guy buidling Guitar fuzz boxes
he is able to select them electronically to lowest noise, highest gain etc...
You can also slightly change the cirquit using new old stock russian low noise
Germanium resistors easily available on ebay.
Noise might be a little higher with them if not selected...
P.S. We Germans love it to overengineer stuff 
Even vintage RIAA boxes if newly built.
Best regards
Willy
thanks for the flowers
the mid box (the silver larger one ) is the adjustable Sulzer - Borbely "TANDEM" Regulator.
it also has an integrated active ANTI HUM device if there should remain any rest of hum coming out of the sulzer reg, it terminates even that (so I can be pretty sure that the 24 Volts DC coming out of that monstrous regulator are quite as a vacuum,
quite as the best battery setup or even quiter...)
The Regulatorbox has a twisted lock "2x Unregulated 35V DC Power In" jack (coming from the transformer, rectifier box),
outcoming ultra quitely regulated twin 24V DC go through japanese TAYMIA RC car loading jacks and cables right to the both RIAA Phonostages.
it does not matter wich power cord from there goes to the left RIAA and right RIAA "Fuzzbox"...
Those RIAA "Fuzzboxes" have TAYMIA power in jack and two RCA tone jacks.
The INPUT JACK is on the side of the power input jack the outcoming is on the other side...so its easy to distinguish.
One might install a FEMALE / MALE RCA Plug system but I dont need it.
The OC and AC Germanium Transistors you can easily get from ITT and Valvo/Philips brand
on ebay germany new old stock or you can "rip out" old transistor scrap radios.
I got mine matched from a guy buidling Guitar fuzz boxes
he is able to select them electronically to lowest noise, highest gain etc...
You can also slightly change the cirquit using new old stock russian low noise
Germanium resistors easily available on ebay.
Noise might be a little higher with them if not selected...
P.S. We Germans love it to overengineer stuff
Even vintage RIAA boxes if newly built.Best regards
Willy
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I found that a good regulated supply may be quiet but the sound IMO is clearer and more precise with batteries, but that may be just mental illness on my part.
sachu888
Spare the tigers, kill me
I found that a good regulated supply may be quiet but the sound IMO is clearer and more precise with batteries, but that may be just mental illness on my part.
Hi Philip,
I have found little harshness in the sound with Power supply,but it is not easily noticeable.
Regards,
Sachin
ghazzer
Senior Member
Sachin: You are using an R-core transformer as opposed to the standard old iron core transformer. Can you make any comments about the 'quietness', or noise suppression of this new type of transformer?
Or maybe you can point us to any research that you or Om reviewed before deciding on the R-core. It sounds like a very interesting and promising development.
I will be using an older iron core xformer that I already had, shielding it and remoting it from the OPS, CNC, LSA & SSP.
.
Or maybe you can point us to any research that you or Om reviewed before deciding on the R-core. It sounds like a very interesting and promising development.
I will be using an older iron core xformer that I already had, shielding it and remoting it from the OPS, CNC, LSA & SSP.
.
sachu888
Spare the tigers, kill me
Hi Steve,
R-core has no sound,no vibration,no humming,buzzing etc.Its totally quiet.Omishra has replaced a Toridal in an amp with R-corr and difference is day and night.Here are some advantages of R-core http://www.shilchargroup.com/Comparision _Chart.htm
Regards,
Sachin
R-core has no sound,no vibration,no humming,buzzing etc.Its totally quiet.Omishra has replaced a Toridal in an amp with R-corr and difference is day and night.Here are some advantages of R-core http://www.shilchargroup.com/Comparision _Chart.htm
Regards,
Sachin
Since you already have the old style transformer remove all of the AC from the chassis with the preamp circuit. A few feet away makes a huge difference.
With this delicate circuitry, low input voltage be certain to use soft recovery Cree diodes. The reverse recovery spike will leave noise on your DC buss.
ghazzer
Senior Member
Yes, it will be 3-4' from the PCAs, and properly shielded and grounded. Main drawback here is that the on/off switch will also be 3-4' away. The OPS PCB is laid out for the rectifier diodes to be mounted on the same substrate. How critical is placement of these diodes? 'Guess I could free wire them in the enclosure with the Xfmr (25-0-25).
BTW: The MA-6100 is now in Knoxville, waiting in Terry DeWick's queue.
BTW: The MA-6100 is now in Knoxville, waiting in Terry DeWick's queue.
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Last first, Terry is 5 minutes from my house. What a nice guy! Not to mention highly talented and the guy for tuner alignment.
You can use a DPDT toggle switch to turn on and off the DC supplies at the phono preamp PCBs. I would simply put in a terminal strip in with the transformer and mount the diodes and first filter cap(s) out there.
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Fasterdamnit
Super Member
dodog
Addicted Member
Nice one. I really like that power switch. Where did you get it? Is this a +/- 18V supply or are there just spares in that box? It looks like only the two on the left are wired up but I can't tell from the shadow.
Fasterdamnit
Super Member
Sachin-
These are wood cigar boxes- most come from mid and South America. I find them at the local flea market on occasion.
It is just a Rat Shack DPDT switch. I, too, like the flat toggle.
Great question about the extra batteries. I wanted to run 4 for 18V but brand new batteries are a bit over 9v so the resultant voltage was about 18.6v and the op-amps did not like that. One channel would cut out. Went back to +/-9v and it works great. So now there are two spare on-board. :yes: