John Curl's Blowtorch preamplifier part III

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Power fets or bipolars ?
On semi NJL3281D MJL1302D three pairs per channel
ES9026PRO
A TPA3255 with good output coils does better. The designers of this amp are surely aware of this. So my question is: are there some trade offs made here between distortion and some other desired quality, and if so, what are these qualities?
Distortion level is not that important
Congratulations to Dimitri for being the happy owner.
Thank you Hans, but I couldn't afford it
 
Thank you Hans, but I couldn't afford it
Like most hi end amp designers, we can't afford what we design.
It's so true, but sometimes, when it's not too big a company and if we are involved in the development up to the final product, there is a way of, let's say, keep one of the prototype, that is not so far from the final product, aside ;-)
We should include this clause in our contracts.

So, you tell me, when a painter sells a painting, he doesn't keep it ! But writers always have some copies of their books.
 
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Looks like the low octave needs work, bass traps, location rearrangement or subwoofer augmentation.

Any other measurements of the room?

No, it rolls off starting at 40Hz... which is the driver/box response rolling off.
For the music I listen to, it is fine.

40 Hz is lowest fundemental on 4-5 string bass guitar.

Electric-Bass-Standard-Tuning.png


Typically, there is little played below 40Hz.


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Thanks for your expert opinion. But, no thanks. Maybe for a video surround sound system for the Effects channel.


As for 'water-fall' displays , time, reverb data etal. This isnt the forum for that. So, that is all you get here about my system.


THx-RNMarsh
 
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Stereophile did some measurements, my dear prof. T.

Classic characteristic ML. The rolled off HF response since day one. A good idea.

And just enough distortion to have a characteristic 'wide and deep" sound field on everything played thru it. to me... more blurred. But a lot of people like it over highly accurate.

The moderate distortion is at only 8 ohm load so things are a lot worse into many speaker loads of less than 8 ohms.

Suspect is the power amp section and not the front-end sections.

IMO.


THx-RNMarsh
 
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I'm not really complaining, I have just about everything audio that I want. However, I have made some very expensive phono stages for Constellation. Of course, I could build one for myself with the remaining Constellation prototype boards, but I am happy with my Vendetta in my CTC preamp. The biggest difference between the Vendetta and the Constellation is balanced input vs unbalanced input. Unbalanced is quieter (for self noise) and simpler. I prefer it. However the Constellation phono stages cost between $30,000 and $85,000, too much for my budget.
 
I am not sure what the question is about? can you be more specific, please? Compared what to what? ...
Comparison of measured acoustic output of amp that has "just enough distortion to have a characteristic 'wide and deep' sound field on everything played thru it" to another amp that "measured highly accurate" wrt. voltage output.

Reason I am interested is because your 0R22 resistor on speaker return that reduce woofer distortion would have an effect on measured distortion wrt. voltage output as well.
 
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