Bear, Qusp and Conrad:
That is about what I am looking for-an amp that does not impose it's sonic character over the music (different goal that a tube lover). So maybe an IC op-amp will be able to do this. Yes a differential test should bear this out.
John:
I see that balanced adds a little noise. To me, if the circuit noise is low enough, I can live with 3db if distortion is cancelled. The Early Borbely preamp is noisier than my op-amp RIAA preamps. I much prefer the sound of the Borbely than the IC unit, even with the noise. I know both designs are far noiser than your design.
Thanks,
Dan
That is about what I am looking for-an amp that does not impose it's sonic character over the music (different goal that a tube lover). So maybe an IC op-amp will be able to do this. Yes a differential test should bear this out.
John:
I see that balanced adds a little noise. To me, if the circuit noise is low enough, I can live with 3db if distortion is cancelled. The Early Borbely preamp is noisier than my op-amp RIAA preamps. I much prefer the sound of the Borbely than the IC unit, even with the noise. I know both designs are far noiser than your design.
Thanks,
Dan
The Borbely ought to be pretty darn quiet - is there a problem active component in there?
(higher than spec noise?)
Is the noise from the front end? (if so, that can be fixed)
Are you using the same supplies for the opamp version and the Borbely?
Is there any RFI getting in?
Keep in mind you said that you preferred the sound of the Borbely over the opamp versions, and neither on paper has distortion that you "ought" to be able to hear, so why do you prefer one over the other??
_-_-bear
PS. there is no bottom on this rabbit hole... enjoy the freefall!
(higher than spec noise?)
Is the noise from the front end? (if so, that can be fixed)
Are you using the same supplies for the opamp version and the Borbely?
Is there any RFI getting in?
Keep in mind you said that you preferred the sound of the Borbely over the opamp versions, and neither on paper has distortion that you "ought" to be able to hear, so why do you prefer one over the other??
_-_-bear
PS. there is no bottom on this rabbit hole... enjoy the freefall!
again what phono cart? - mc hi/lo output, mm?
really optimising design requires knowing source signal level, impedance characteristics
this is true for discrete and op amp based designs - you really have to choose a class of phono cart to proceed with a proper design
lo output moving coil carts preamps could use some low noise bjt input op amps
the same op amps would give high noise, possible errors from high bias current with a moving magnet, high inducatance cart
really optimising design requires knowing source signal level, impedance characteristics
this is true for discrete and op amp based designs - you really have to choose a class of phono cart to proceed with a proper design
lo output moving coil carts preamps could use some low noise bjt input op amps
the same op amps would give high noise, possible errors from high bias current with a moving magnet, high inducatance cart
Bear:
(JCX: I am using a moving magnet cartridge. 681EEE, V15, SC35, etc)
Erno's April 1985 Audio Amateur magazine project EB585 preamp has a single set of 2SK147/2SJ73 JFET transistors as the first stage. With these transistors, and the fact that they are not paralleled with more sets, the noise is not as low as any of his newer designs. My guess is the noise is about -60 to -70db. Have not measured it. I believe this is his first published preamp kit.
I feel that a small amount of noise is probably entering from the power supply, as they are regulated with the LM317/337 set-not a lower noise Jung style. Finally, I suspect that some noise that may be generated by the 15v zeners may be entering the base of the cascode transistors and passing to the input FET's. Finally I feel I do have a noisy transistor in the front end of one channel as it is about 6db noisier than the other channel. I have some replacement FETS (2SK170BL/2SJ74BL's) that I'll try in about a month when I get time.
Also, as Borbely splits the HF roll-off and the LF EQ in separate stages (with the HF roll-off first, then the LF EQ in the second. I feel that the HF noise in the second stage never gets attenuated by any HF roll-off as it was already done earlier), to me this should be more noisy than a single stage op-amp that has composite EQ on the feedback loop of the IC, where the HF noise of the one stage is attenuated by the RIAA HF rolloff.
There is no RF getting in the preamps-I checked with a scope. My IC preamp is being fed by a Lambda +/-15v supply that uses an LM723 into 2N3055's- quieter than the 3-terminal regulators, but most probably not as quiet as a Jung.
As far as my preference, I feel the Borbely is more "open" and "clear" than any of my op-amp units. Not sure why, but in reading I suspect the Borbely has no crossover distortion or IM in the midrange and high end as compared to my IC op-amp units. Still reading about what may cause the sonic differences.
Finally, you'll choke at what I listen to-an iPod in the Corolla with a stock stereo system! Next I use Sony 7506 headphones and a Hafler DH200 and Ohm B speakers.
Only the best!
Dan
(JCX: I am using a moving magnet cartridge. 681EEE, V15, SC35, etc)
Erno's April 1985 Audio Amateur magazine project EB585 preamp has a single set of 2SK147/2SJ73 JFET transistors as the first stage. With these transistors, and the fact that they are not paralleled with more sets, the noise is not as low as any of his newer designs. My guess is the noise is about -60 to -70db. Have not measured it. I believe this is his first published preamp kit.
I feel that a small amount of noise is probably entering from the power supply, as they are regulated with the LM317/337 set-not a lower noise Jung style. Finally, I suspect that some noise that may be generated by the 15v zeners may be entering the base of the cascode transistors and passing to the input FET's. Finally I feel I do have a noisy transistor in the front end of one channel as it is about 6db noisier than the other channel. I have some replacement FETS (2SK170BL/2SJ74BL's) that I'll try in about a month when I get time.
Also, as Borbely splits the HF roll-off and the LF EQ in separate stages (with the HF roll-off first, then the LF EQ in the second. I feel that the HF noise in the second stage never gets attenuated by any HF roll-off as it was already done earlier), to me this should be more noisy than a single stage op-amp that has composite EQ on the feedback loop of the IC, where the HF noise of the one stage is attenuated by the RIAA HF rolloff.
There is no RF getting in the preamps-I checked with a scope. My IC preamp is being fed by a Lambda +/-15v supply that uses an LM723 into 2N3055's- quieter than the 3-terminal regulators, but most probably not as quiet as a Jung.
As far as my preference, I feel the Borbely is more "open" and "clear" than any of my op-amp units. Not sure why, but in reading I suspect the Borbely has no crossover distortion or IM in the midrange and high end as compared to my IC op-amp units. Still reading about what may cause the sonic differences.
Finally, you'll choke at what I listen to-an iPod in the Corolla with a stock stereo system! Next I use Sony 7506 headphones and a Hafler DH200 and Ohm B speakers.
Only the best!
Dan
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Dan:
This is from Borbelys old webpage:
The All-FET phono preamp is a very sensitive amplifier and is capable of picking up small signals not only through its inputs, but also through vibration. It is therefore very important to make the whole amp as “dead” as possible from vibration. It is recommended to mount the board in a vibration-free way. There are several possibilities here; one is to use rubber standoffs, which are specifically made for this purpose. Further improvement can be achieved by mounting the whole board on a Teflon plate, 6-8mm thick. And a mumetal box will certainly put the icing on the cake…
The EB-707/432 ALL-FET MM/MC phono preamps input stage was specified as having <100 nV equivalent short circuit input noise. What I can see the only difference is that it uses four paraleled FETs at the input.
Hope this heps.
This is from Borbelys old webpage:
The All-FET phono preamp is a very sensitive amplifier and is capable of picking up small signals not only through its inputs, but also through vibration. It is therefore very important to make the whole amp as “dead” as possible from vibration. It is recommended to mount the board in a vibration-free way. There are several possibilities here; one is to use rubber standoffs, which are specifically made for this purpose. Further improvement can be achieved by mounting the whole board on a Teflon plate, 6-8mm thick. And a mumetal box will certainly put the icing on the cake…
The EB-707/432 ALL-FET MM/MC phono preamps input stage was specified as having <100 nV equivalent short circuit input noise. What I can see the only difference is that it uses four paraleled FETs at the input.
Hope this heps.
Tom:
I saw that a while back. jFETS seem to be very sensitive to thermal changes (which I see with a scope) and as some of this is high impedance, circuit board vibration becomes a small issue. My issue is not vibration. The preamp is in a steel box and the room is pretty quiet when I am seeing the noise.
Yes Borbely's newer preamps have paralleled FET's as compared to my unit. On my unit. the good channel noise is not too noisy, just more noisy than my preamp with the LM394 front end and the RIAA network in the feedback loop.
Not complaining about that as when listening at normal levels the noise is not an issue. When you put headphones on and listen to an LP between tracks, you hear a little noise at the level of the surface noise of the LP. The other channel is a bit higher-something that needs to be corrected.
Thanks!
Dan
I saw that a while back. jFETS seem to be very sensitive to thermal changes (which I see with a scope) and as some of this is high impedance, circuit board vibration becomes a small issue. My issue is not vibration. The preamp is in a steel box and the room is pretty quiet when I am seeing the noise.
Yes Borbely's newer preamps have paralleled FET's as compared to my unit. On my unit. the good channel noise is not too noisy, just more noisy than my preamp with the LM394 front end and the RIAA network in the feedback loop.
Not complaining about that as when listening at normal levels the noise is not an issue. When you put headphones on and listen to an LP between tracks, you hear a little noise at the level of the surface noise of the LP. The other channel is a bit higher-something that needs to be corrected.
Thanks!
Dan
Rational? Experience shows me that IC's do NOT sound as good as discrete devices put properly together, YET! If they did, I would switch to IC's almost exclusively. However, standard MEASUREMENTS will not bring out the significant difference that is found in listening. That is the problem. Leaving out the listening opinion, that remains consistent in my experience, makes a person believe, because of measurement, what is NOT TRUE. I.E. that measurement are all someone needs to build a successful audio product.
John,
You are trying to lay a RDBT (reverse double blind test) thingy on me.
Do a DBT between a good IC based design and a good discrete design and then make that statement. The LP's and CD's most of us listen to have been through dozens of 5532/4's and even more electrolytics. If there is anything in the sound you don't like, it's more than likely what is coming off the disc that's the problem.
The issue here is that blind statements about discrete designs sounding better are being made with no proof. No measurements to back it uo, no insistent DBT results, nothing.
We have a whole industry corrupted by anti opamp,anti feedback nonsense.
You are trying to lay a RDBT (reverse double blind test) thingy on me.
Do a DBT between a good IC based design and a good discrete design and then make that statement. The LP's and CD's most of us listen to have been through dozens of 5532/4's and even more electrolytics. If there is anything in the sound you don't like, it's more than likely what is coming off the disc that's the problem.
The issue here is that blind statements about discrete designs sounding better are being made with no proof. No measurements to back it uo, no insistent DBT results, nothing.
We have a whole industry corrupted by anti opamp,anti feedback nonsense.
are you telling us that the industry is already corrupted by allegedly false claims, or that it could become corrupted if these claims continue to be made.
Hi, if you can drop the J-Fet requirement, which for MC phono is not really an issue, there are quite a few CFB Op-Amps that have nearly the needed noise and way ace all other requirements.
Sadly they did not sound as good as a stock l'Pacific open loop J-Fet Phono...
My Best Op-Amp Phono was AD811 in "Phonoenhancer mode" (cartridge directly into the inverting input) with 75uS/3.18uS in the feedback loop followed by a LM6181 with 3180/318uS in the feedback loop (all very low impedance), linestage was another LM6181 with minimal gain followed by a 100R 10-turn wirewound pot as volume control. It was not a lot better than the "analogue addicts phono" but heck of a lot harder to build....
The l'Pacific was so dramatically better, subjectively, it was not funny.
Ciao T
I use independent reviews to make my statement for me. I trust what I hear, but I do not completely rely on it, and independent reviews are needed to confirm my listening opinions. Of course, some people don't believe in independent reviews, either, but I do.
Like Richard Heyser said many decades ago: 'IF two people hear something, then it is real.' RIP Richard.
Like Richard Heyser said many decades ago: 'IF two people hear something, then it is real.' RIP Richard.
Yes, I completely agree, but if I would have said that some Op Amps "did not sound as good" to Bonsai he would have said I´m a deluded subjectivist, so I tried it with some
measurable specs. But now these don´t matter too...
I attend classical concerts regularly (at least once a month) and I´m pretty sure
that a NE5534 is not all I need. (But without a double blind test I´m of course just
deluded. Unfortunately I can´t afford the Vienna Philharmonic for such a test. ;-)
measurable specs. But now these don´t matter too...
I attend classical concerts regularly (at least once a month) and I´m pretty sure
that a NE5534 is not all I need. (But without a double blind test I´m of course just
deluded. Unfortunately I can´t afford the Vienna Philharmonic for such a test. ;-)
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