PMA is only 1/2 right here. Actually it is better to avoid Toroid power transformers for preamps, at least, and use either E-I or R core. Parasound uses R-core, the Blowtorch uses special E-I. Both units use extra large transformers and lots of capacitance. We also take some steps to reduce peak current problems, as this is important, as well. We could discuss this sort of thing, like we used to, on this thread, if given a chance.
In my personal experience, I find very few warped records in my collection. Perhaps I store them better.
In audio, the proof is in the listening comparison. IF there is none, and every effort to bring a difference out is made, then don't bother. However, if there is a difference, and it is 'obvious' then forget engineering 'rules of thumb' and do it the 'right' way.
I had NO IDEA that I could improve one of Nelson's preamps so much by making a custom supply with everything increased in capacity. I just made it for a customer, who paid me to do it. I thought it was a charity project, where the customer wanted to give me a project so that I could more easily pay my rent that month. Only when I heard the A-B difference along with Gordon Holt, who immediately bought the improved power supply from my customer, and wrote it up in 'Stereophile' that I realized that an 'oversized' power supply could be significantly better sounding.
I then proceeded to rebuild the Vendetta SCP-2 power supplies to the same standard, and this became the SCP-2A, my first mod. This is how I acquire experience in what works, and what is just adequate engineering.
I had NO IDEA that I could improve one of Nelson's preamps so much by making a custom supply with everything increased in capacity. I just made it for a customer, who paid me to do it. I thought it was a charity project, where the customer wanted to give me a project so that I could more easily pay my rent that month. Only when I heard the A-B difference along with Gordon Holt, who immediately bought the improved power supply from my customer, and wrote it up in 'Stereophile' that I realized that an 'oversized' power supply could be significantly better sounding.
I then proceeded to rebuild the Vendetta SCP-2 power supplies to the same standard, and this became the SCP-2A, my first mod. This is how I acquire experience in what works, and what is just adequate engineering.
Last edited:
There's a good engineering reason for that- toroids have great bandwidth, exactly what you don't want for a power transformer.
I assume so have the folks at Boulder with all their 8-legs in the signal path, they certainly sit at a price point even rave Fremer reviews.
That's what I ended up using in my current line preamp (6 channel Heretical). Some line filtering, common mode filtering on the secondary end, good grounding practice, and Bob's your uncle.
Sy,
Then I take it you placed the electronic xo before the six pre's instead of after a pair of pre's going to your six amps. Why did you take that approach rather than a simpler 2 pre's with the active xo between that stage? Perhaps you are using a digital xo before the six pre's that would explain it, a dsp perhaps?
Then I take it you placed the electronic xo before the six pre's instead of after a pair of pre's going to your six amps. Why did you take that approach rather than a simpler 2 pre's with the active xo between that stage? Perhaps you are using a digital xo before the six pre's that would explain it, a dsp perhaps?
Yes, the pre comes after the XO and before the power amps. My XO (a DCX2496 with passive RC outputs) is fed with SPDIF and I want to minimize its noise by having the gain structure optimal at any volume setting.
I'm sure it meets their house sound requirements .....
Pics or just some ... err.....
as i said before , at your level ..... Pics .. - Status
- Not open for further replies.