John Curl's Blowtorch preamplifier part II

[john curl]

Ever onward. The best general topology I have found for either discrete or IC based phono designs is: Ultra fast, low noise, first stage gain block, passive 75uS roll-off, second stage fet input with feedback using other RIAA EQ elements.
This has been used with the JC-80, Vendetta SCP-2, Parasound JC-3, and the new Constellation Orion phono stage, coming soon. It is NOT the only approach: Perhaps just as good, or even better in some ways is the all passive EQ first used by Walt Jung, but also used by SY in his tube phono stage, on this website, and the Vendetta V3, coming someday, if I live that long. ;-)

 

[Joachim Gerhard]

I had success with active shunt feeback. I came up also with an active - passive combination implemented in an INA made from 3 Opamps.

 

[john curl]

INA's are unnecessary with 3 op amps IN THIS PROJECT, because they are extra noisy. Please, think it through.

 

[scott wurcer]

Did I confuse everybody? Sorry, that is how we talk around here, in some districts.

Keeps the wimmin away too.

 

[john curl]

Well, IF you go to CES, I will make sure that you are not asked to go to the Palomino, not that I would expect you to want to, anyway. This previous message was directed at the Europeans, who might know who:Benrd Ahne is, as he lives in Berlin.

 

[john curl]

In any case, we should try for a 1-2nV/rt Hz inclusive input noise design, so that Denon 103 or equivalent MC cartridges can be comfortably used without a serious noise penalty.

 

[Joachim Gerhard]

So what whould work is a linear stage at the input, then the 75usec passive, then a second stage with 318usec and 3180usec active ?
Yes, the INA will be 3dB more noisy.

 

[Joachim Gerhard]

I know Bernd of cause.

 

[john curl]

Yes, it would, and it is a bit too much, at the moment. Also, let's start with single ended. There is nothing wrong with single ended input. Generally, it is quieter, less complex, and most people here, like me, are too unsophisticated to have balanced audio cables from their turntable.

 

[john curl]

Well, I like Bernd, and we will 'hang together' (local dialect for 'meet up, usually for social activities') at CES, at some point. Got an E-mail from him, how about you? He is usually our 'designated driver'. ;-)

 

[scott wurcer]

Well, IF you go to CES, I will make sure that you are not asked to go to the Palomino, not that I would expect you to want to, anyway. This previous message was directed at the Europeans, who might know who:Benrd Ahne is, as he lives in Berlin.

Don't worry the CES makes the bottom of my list every year the venue being half the reason.

 

[Joachim Gerhard]

Ok, here is a simple bloch diagram.

 

[hitsware]

Yes, it would, and it is a bit too much, at the moment. Also, let's start with single ended. There is nothing wrong with single ended input. Generally, it is quieter, less complex, and most people here, like me, are too unsophisticated to have balanced audio cables from their turntable.

What the world needs is a balanced turntable
hookup that appears singled ended.................

 

[john curl]

Well, MY hookup is single ended and it will remain that way. I also drive 2 wheel drive vehicles and don't expect to go to 4 wheel drive, for much the same reason.

 

[Joachim Gerhard]

I have a balanced and a sigle ended setup and in both cases i get the humm down to nearly zero, so i agree. In a home environment single ended works fine and is more economical. Also with the same amount of input devices you get 3dB less noise.

 

[pooge]

Yes, it would, and it is a bit too much, at the moment. Also, let's start with single ended. There is nothing wrong with single ended input. Generally, it is quieter, less complex, and most people here, like me, are too unsophisticated to have balanced audio cables from their turntable.

Oh Sy, you sophisticate, you!

 

[pooge]

Well, MY hookup is single ended and it will remain that way. I also drive 2 wheel drive vehicles and don't expect to go to 4 wheel drive, for much the same reason.

Because you live in berkeley??

 

[Joachim Gerhard]

One could add a transformer anytime. They are not cheap but models from Lundahl and Sowter are affordable and very good.

 

[john curl]

Joachim, have you compared the Lundahl with the Sowter? Only serious response, please. I have not, and I am technically curious.

 

[Steve Eddy]

Joachim, have you compared the Lundahl with the Sowter? Only serious response, please. I have not, and I am technically curious.

Also consider the CineMag CMQEE-3440A.

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