John Curl's Blowtorch preamplifier part III

[SyncTronX]

@Ray, Chris, DPH, Richard, John, Ultima:

Thanks for the clarifications and explanations and the insight. I'll get there. Growing Pains and at my age, who'd of thunk it.

Cheers,

 

[waltzingbear]

gain less than unity (1) is attenuation

positive and negative gain refers to polarity referenced to the original signal.

Cheers
Alan

 

[john curl]

It can be somewhat confusing, but: X50 or -X50 seems clear enough, and 6dB and -6dB means something else completely, or '2' and '1/2' which removes the (-) sign and the polarity completely.

 

[jan.didden]

In more formal publications you often see the absolute value of Vout/Vin as the gain value, without any phase information.

Like G = |Vout/Vin|.

This caters for gains both greater and smaller than 1 without confusion with a minus sign.

Jan

 

[scottjoplin]

Or a little mountain or valley symbol on the schematic at the input and output, my brain can handle that

 

[chris719]

They will sell plenty, because they made a good sounding product.

Have you heard it? I dare that say just because they weigh 200 lbs and are priced close to a Porsche 911 does not make them any good. The measurements are frankly embarrassing, I know you wouldn't put your name on that.

 

[scottjoplin]

I wasn't born yesterday, so I know a $93K amplifier doesn't get sold because it sounds good

 

[jan.didden]

Often sales of these products are low or zero, but they are a statement product positioned to increase sales of lower priced products inheriting the reputation and wow-factor. As a customer you can brag that you have 90% of the technology and performance of the top model at an affordable price point.
It is a well-known marketing ploy.

Jan

 

[john curl]

This amp most probably sounds excellent, because it runs open-loop with a tube front end. It probably has a big power supply also, adding much to its weight. If Fremer likes it, then I probably should give it a listen sometime. Perhaps at a show.

 

[PMA]

If Fremer likes it,

Yes, he often likes very extraordinary things.

He also prepared A/D digitized "hirez" files recorded from LP's to demonstrate different "sound quality" of various phone cartridges/turntables. Technical quality of these recordings was so poor that I can hardly understand how he could publish such thing. Or maybe I understand quite well. Based on what he likes, I would probably avoid it first.

Technics SL-1200G Versus Continuum Caliburn And SAT Arm | Analog Planet

 

[PMA]

This is what Fremer is giving to audiophiles. Cartridge resonance + tons of groove noise. And no real highs, they end at 13kHz. Aif files in the previous link. Good sound?

 

[billshurv]

He's gone one better with some rips of 10K cartridges recently!

 

[hitsware]

The xfmr gain in the amp would lend to an at least distinctive,
and perhaps delightful sound. (specs be damned)

 

[john curl]

PMA, you do yourself no favor attacking Fremer if you want to be in the hi end audio community. Technical complaints aside, it is like you being a wine maker and attacking a prominent wine taster. It just does not help your cause.
For the record, I hate comparisons like what he put up between the turntables, but then I hate digital as a rule as well. I have heard the Continuum several times on different quality systems, and I liked it.
I have not heard the latest Technics turntables, but I am usually disappointed in their sound, and I gave away one to one of my technicians without even listening to it.

 

[anatech]

Hi John,

I have not heard the latest Technics turntables, but I am usually disappointed in their sound, and I gave away one to one of my technicians without even listening to it.

That would be a certainty if you are expecting a really nice turntable. I doubt the arm does it any favors either. It just isn't designed to be a high end product.

-Chris

 

[Destroyer OS]

Often sales of these products are low or zero, but they are a statement product positioned to increase sales of lower priced products inheriting the reputation and wow-factor. As a customer you can brag that you have 90% of the technology and performance of the top model at an affordable price point.
It is a well-known marketing ploy.

Jan

Ya... I dont know about that. I seem to see a fair bit of ownership. It is probably more true in other fields.

 

[scott wurcer]

and I gave away one to one of my technicians without even listening to it.

True to your signature line? Mr. F gave a very favorable review to my $200 kickstarter turntable. I think cart and table ended up $279. U-Turn’s Remarkable $179 Orbit Turntable is A Crosley Killer! | Analog Planet

 

[billshurv]

Chris: easy enough to change the arm on the older SL-1200 at which point it becomes most definately high end in all but looks. I'd still rather hold until until one day an affordable SP-10 MK2 comes my way, but that might be a very long time.

Can't find the review online anymore, but the Dave Cawley modified SL-1200 with SMEV arm was the cleanest measuring TT they had seen. How much that matters in the hamstrung technology that is rock dragging through plastic is up to the consumer to decide .

Aside: Best set of Rotational measurements I have seen are off JP's Nak TX1000, with his SP10 a close second and the SL1200 a still close third.

 

[scottjoplin]

Ya... I dont know about that. I seem to see a fair bit of ownership. It is probably more true in other fields.

Yes, I don't think ultra high end audio is a field where you'd brag about being a peasant

 

[dadod]

I think I know the preamp;-)
So, we have a preamp witch works in two configurations, *with the same components*.
If I remember well, the distortions were low enough in both modes to can exclude any difference to come from there. Despite this, a lot of people tend to make the difference and have a preference. And I tend to believe there is really a difference in the presentation..
Now the question is; why ?
The only answer I can imagine is : Dynamic behavior.

Exactly, the same circuit/components, with the gain difference of both modes is 0.13 dB. The mode set by change just one jumper(J1 or J2), schematic attached.
I am inclined on the NFB side, but here I could not decide.
Damir