John Curl's Blowtorch preamplifier part II

Status
Not open for further replies.
More than a few, at this point. :D Having actually been there and knowing well the sound of those particular voices and instruments from repeated exposure, I'd humbly submit that I know when the reproduction is realistic, within the limitations of the stereo paradigm.

If you get the idea that I won't/don't listen to poor recordings of great music, I've done a poor job of communicating. Sturgeon's Rule applies- 95% of the music I have is poorly recorded or mastered.
 
More than a few, at this point. :D Having actually been there and knowing well the sound of those particular voices and instruments from repeated exposure, I'd humbly submit that I know when the reproduction is realistic, within the limitations of the stereo paradigm.

If you get the idea that I won't/don't listen to poor recordings of great music, I've done a poor job of communicating. Sturgeon's Rule applies- 95% of the music I have is poorly recorded or mastered.
Then the ghost Rise Stevens will not have to haunt you.
 
AX tech editor
Joined 2002
Paid Member
There is a tight rope walk with this. Having a system that sounds the best with only the best recordings means you fell over to the side of audiophiledom

But how can this be? How can a system sound best with good recordings? Isn't it the RECORDING that is supposed to sound - with the amp only tasked with reproducing whatever is thrown at it - good recordings, bad recordings - as faithfully as possible?

Iow, a good amp should not add or subtract or change anything, just transparently reproduce. Thus, bad recordings sound bad, good recordings sound good - precisely because a good amp doesn't add it's own opinion.

Jan
 
Last edited:
But how can this be? How can a system sound best with good recordings? Isn't it the RECORDING that is supposed to sound - with the amp only tasked with reproducing whatever is thrown at it - good recordings, bad recordings - as faithfully as possible?

Iow, a good amp should not add or subtract or change anything, just transparently reproduce. Thus, bad recordings sound bad, good recordings sound good - precisely because a good amp doesn't add it's own opinion.

Jan

Well, I guess it depends how bad the recordings are and how tolerant the listener is to them. I'm not gonna sit there gritting my teeth thinking that I should be enjoying a bad recording just because I have transparent audio system. If I wanted that I could get a dentist to drill my teeth. Luckily for me I find quite a large part of my music collection to be quite reasonable quality. For some reason - perhaps the complexity of the recording there seem to be a disproportionate amount of classical recording that are below par.

. . . and you guys with analogue systems are in a different universe - you have all kinds of background noises to mask out all the nasties - Let's face it analogue can be the cleverest prettifier of all :)
 
While some WANT forgiveness, I find that accuracy WITHOUT significant added irritation can give the best possible sound. That is my goal, at least.
Many good amps add 'irritation' due to residual higher order non-linearities.
Some 'open loop' tube amps don't add 'irritation' but they are not completely accurate. That has been our dilemma for decades. How do we get both?
 
"The amplifier is connected to my more than 10 years of experience in the construction of power amplifiers HighEnd, verification of circuit topologies and countless listening tests.

Amplifier topology is complementary - differential and symmetrical from input to output. This means that both input and output are balanced. The output is not connected to earth. This topology allows a maximum suppress noise voltage penetrating the output of the power supply. Improved suppression of noise voltage to unbalanced output topology is about 30 dB.

Obvodobé solution is the MOSFET from input to output. These elements are all types of semiconductor greatest resistance to interference. The amplifier does not use feedback from output to input."

"Description

MOSFET stereo amplifier concept celosymetrická. Input: Balanced (XLR). Output: symmetrical. No overall feedback.

Parameters

Output Power: 2 x 100W / 4 ohm, 2 x 75W / 8 ohm
Input impedance 20kohm (symmetrical)
Frequency response 2 Hz - 65kHz (-3dB)
Gain 31 db
Dimensions 450 x 440 x 140 mm
Weight about 20 kg

It current limits between 8/4, its a toy ...... :cool:

I just listened to an LP rendition of a 1943 performance with Horowitz/Toscanini RCA Red Seal, of Tchaikovsky Piano Concerto No. 1, that I got for less than $1, and it sounds great, with no obvious problems. That is what good playback equipment gives.

Yep, especially at $1..........
 
For Higher order non linearities surely the first approach is heavy biasing, then after that going through the design element by element and eliminating every possible source of HF resonance with suitable damping measures and having no unsoldered connections anywhere - can't think of anything else.

edit: John, One thing I really don't understand is how you get your amps sounding good without using snubbers on your bypass caps. For me this is a recipe for a bad sound - am I missing something ?
 
Last edited:
AX tech editor
Joined 2002
Paid Member
Well, I guess it depends how bad the recordings are and how tolerant the listener is to them. I'm not gonna sit there gritting my teeth thinking that I should be enjoying a bad recording just because I have transparent audio system.

Yes indeed. I have lots of CDs and LPs that are really bad recordings, and I don't play them after the first few tries.
OTOH, music I really like I can enjoy no matter the system - even on the kitchen table radio. Go figure ;)

Jan
 
But how can this be? How can a system sound best with good recordings? Isn't it the RECORDING that is supposed to sound - with the amp only tasked with reproducing whatever is thrown at it - good recordings, bad recordings - as faithfully as possible?

Iow, a good amp should not add or subtract or change anything, just transparently reproduce. Thus, bad recordings sound bad, good recordings sound good - precisely because a good amp doesn't add it's own opinion.

Jan
I have heard systems that sound great with great recordings then collapse with so-so stuff. The most recent one I can remember was at T.H.E show last summer. Coffman Lab's - some of the best sound I heard. BUT only with great recordings. Lounge Audio LCR went through a pivital design change at the end of 2011 because of similar reasons. Maybe I'm letting my green designer skills, or lack, of show; But I have run into this crossroad more than a few times.
 
Status
Not open for further replies.