After building lots of prototypes, first unbalanced and later with balanced inputs, I settled at the configuration show in this post. The posted configuration was considered the best sounding one that I have build and presented to my listening panel (actually 4 people, all used to listen to life music and owning high end audio systems).
I’m sure that posting these schematics is not going to make me famous, and I am aware of the fact that critiques here may make me look a bit silly. But I need to know, what do you diy people here, whose messages I am reading for years on end, think about the thing I concocted .
Let me know what you think of it…
Regards,
Frans de Wit
I’m sure that posting these schematics is not going to make me famous, and I am aware of the fact that critiques here may make me look a bit silly. But I need to know, what do you diy people here, whose messages I am reading for years on end, think about the thing I concocted .
Let me know what you think of it…
Regards,
Frans de Wit
Attachments
Very nicely build ! I like the chambers. The LME49710 is a bit noisy for MC work, so are the 51 Ohm resistors. Topology is fine but i whould use the new LME4990, reduce the 51 Ohm to 10 Ohm and take 1.2kOhm feedback resistors. I really like the simplicity of your design and you did a major efford in the PSU so why waisting SN in the input stage ?
I do not know if that new OPamp is freely awaillable I got mine as free samples.
You could also try the AD797, LT1115, LT1020, OPA211, OPA1611 and there is a new low noise chip from Analog Devices.
I do not know if that new OPamp is freely awaillable I got mine as free samples.
You could also try the AD797, LT1115, LT1020, OPA211, OPA1611 and there is a new low noise chip from Analog Devices.
When possible I will do a test with the proposed components, as I do not own a MC cartridge and my TD160b with SME3009 is not suitable, I need to arrange to use my friends player (and he lives Paris [I am in Holland]).
There is an audio sample available that was recorded using a Koetsu Rosewood Signature on a SME Series 20/2 record player. (For me it sounds like virtually noise free).
http://www.diyaudio.com/forums/digital-line-level/35621-diy-adcs-4.html#post2015941
Regards,
Frans de Wit.
Can you elaborate a bit on that, and maybe hint at a replacement strategy?
Regards,
Frans.
I consider series regs, such as you are using, are as outdated for good sounding audio as paper in oil caps.
Constant current fed shunt regs are very little more complex to build, but offer huge sonic benefits. There are numerous CCS/Shunt circuits here on DIYAudio.
And I agree with the other poster - your input R's are WAY too large for SOTA noise levels - especially on the MM inputs.
Regards, Allen
Constant current fed shunt regs are very little more complex to build, but offer huge sonic benefits. There are numerous CCS/Shunt circuits here on DIYAudio.
And I agree with the other poster - your input R's are WAY too large for SOTA noise levels - especially on the MM inputs.
Regards, Allen
What abouit upgrading to these
NewClassD UWB Regulator
The typical MM cartridge needs to see a 47k impedance, the selected values correspond with that. Is what you are saying, making a compromise on matching impedance in favor of lowered noise?
Regards,
Frans de Wit.
Last edited:
Yes, the LME49990 is very good in terms of technical data and the circuit i build with it sounds very musical. Thanks for telling me what resistors you use. i know this ones and they have good properties. Have not tried them sofar.
Concerning PSUs for modern Opamps you have to consider that they have very good PSU
suppression so do not expect a miracle when you go to shunt.
Concerning PSUs for modern Opamps you have to consider that they have very good PSU
suppression so do not expect a miracle when you go to shunt.
Yes I know, but this is an all out (at the least almost no expenses spared) design, if improvements can be made than I will consider.
On the other end, the PSU is really good filtered, I suspect that there is nearly no ripple at the regulator input, so the regulators are in a sort of constant current mode (the amount of current taken by the opamps is near constant) and there is a denoising stage after the regulators (using LME49710s) this should be nearly (if not totally) noise free (I suspect).
Any thoughts on this?
Regards,
Frans de Wit.
<at the least almost no expenses spared> For this type of design.
The INA217 looks interesting, maybe PBW and/or low frequency noise are a bit of a problem. You should definitely have a look at the CMRR, this is only 100db (compared to 120db for the LME49710). As I am a believer in simplicity it would not be my first choice, but one could make a little test and (almost) drop it in the schema I am using.
When i go after D.Self you already did a great job but on this forum are many fans of shunt PSU´s. I compared the LC Audio Low noise supply ( series ) with the Twisted Pear Placid ( shunt ) and heard a small improvement in terms of sweetness of sound, low level resolution and bass quality but it was not night and day.
I've been hearing this since the time of the LF351 but upgrading the 3-terminal horrors with superregs, or even better, shunt regs has always brought a very substantial improvement. Of course YMMV.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.