Six Acoustics York Review (phono pre-amp)

[Angsty]

You don't really need to test a phono preamps. The distortion of a cartridge is 3 to 10%. The quality doesn't matter.

Then why bother to test DACs given their THD+N levels tend to be orders of magnitudes lower than loudspeakers or integrated amplifiers?

I'm hoping that was a sarcastic comment, @Ralf Stocker .

 

[cgallery]

Not exactly. Nothing is fixed in stone. There are an infinite number of solutions that fit the desired curve.

Personally, I start by selecting one of the capacitor values. It could be random, but I aim for something standard in value. Then I calculate the resistor values around that. You don't have to chose the same capacitor I do! There are hundreds of phonostage designs out there that use different values than I do. I also split the passive EQ into two separate sections. That is not necessary! You can do it in one.

Regarding the inverse RIAA circuit, as I showed above there is more than one solution. Depends on the attenuation you are aiming for. The original circuit from Lipshitz was at -44dB. I shifted it up to -40dB and added the 3.18us zero. A number of companies have copied my exact circuit and sold as their own, including York. Why don't they sell the Lipshitz instead?

FWIW - the best reason for passive EQ is how it handles overloads such as pops and tics. I believe the testing here uses steady-state sinewaves, but you really need to use an impulse instead. It makes a huge difference, especially with tube circuits. A tic through a passive EQ will just clip and then recover without delay. If the EQ is in feedback loop, what happens is that during the transient the circuit goes open loop, which causes a very audible slew distortion, plus a recovery time to get the loop closed again. That results in greatly exaggerating the tic. Better to clip and move on than to go bezerk and recover.

Okay thanks for the explanation.

I do understand that as more products from a competitor appear to share identical component values (to yours), the chances of it being merely a coincidence become vanishingly small.

 

[Bob from Florida]

Ralf Stocker said:
You don't really need to test a phono preamps. The distortion of a cartridge is 3 to 10%. The quality doesn't matter.

Then why bother to test DACs given their THD+N levels tend to be orders of magnitudes lower than loudspeakers or integrated amplifiers?

I'm hoping that was a sarcastic comment, @Ralf Stocker .

It was trolling designed to elicit a response......

 

[Ralf Stocker]

Then why bother to test DACs given their THD+N levels tend to be orders of magnitudes lower than loudspeakers or integrated amplifiers?

I'm hoping that was a sarcastic comment, @Ralf Stocker .

Maybe. If you have a DAC with double zero THD and one with triple zero THD, and a speaker with 5% THD, then you won't hear any difference. The speaker dominates.

 

[Angsty]

Maybe. If you have a DAC with double zero THD and one with triple zero THD, and a speaker with 5% THD, then you won't hear any difference. The speaker dominates.

This is the measured lateral distortion curve (black fill) of the Zephyr MIMC Star.

Not quite as bad as stated across the board, but certainly higher than most solid state electronics. FR matters (after the RIAA curve is applied) as all phonos do not do a great job with it.

Soundsmith Zephyr MIMC Star Cartridge Lab Report

Lab Report Depending on where you look – the website, downloadable 'manual' or engraved on the bottom of the Zephyr MIMC Star's wooden case – the suggested tracking force varies from 1.8-2.0g, 1.6-2.0g and 1.8-2.2g. I performed all my tests at 2.0g where this 'moving-iron' pick-up tracked like a...

www.hifinews.com

 

[Jim Hagerman]

chosen topology sort of dictate the values of the parts

Here's more proof that there is an infinite number of solutions. Just change the capacitor value choices and the rest is done for you...

AnyEQ: Equalization

Hagerman Technology LLC - innovative vacuum tube products

www.hagtech.com

 

[Tubejack]

WRT noise and headroom, I use a 20V highly regulated linear PS. Brings the performance of these parameters up another level (per my listening only, not by instrument testing. Noise now non-existant at ear in driver distance.) I verified use of 20V PS with 6A as acceptable (vs 18V SMPS wall-wart.) Used with Ortofon MC Quintet Black S .3mv.

 

[BadAudioAdvice]

Do you have a link for the PS you are using?

 

[Tubejack]

Do you have a link for the PS you are using?

There are several sources like this. https://www.ebay.com/itm/353105734120. I communicated and wanted a 20v unit, which they sent. However, I believe they have internal adjustability over a voltage range. My unit is very stable and has extremely low noise as measured on a scope.

 

[BadAudioAdvice]

@Tubejack Thank you for the link, do you know offhand what DC plug size the York uses?

I'm tempted to order this and have it shipped to Amir for review, and also send the York again to review with the new power supply.

But I'm also thinking that I'm just throwing good money after bad, investing more into this...

 

[Tubejack]

The plug is the standard Output DC cable plug type: default 5.5*2.5mm (Polarity: Internal + / outside - ) as the jack on the York.

I don't consider it a bad phono pre. I think Amir's results verify that out, aside from noise and headroom. As he said, his negative recommendation was marginal. There are many positive reviews on the York. I drive DIY 2A3 amps and 97db efficient OB speakers (active biamped at <68hz with sand amps on the dual 15" woofers/side). Not sure what else I would buy in the price range. As an aside, Jim Hagerman claims it is a copy of his Bugle3 design. (See comments under the review https://www.analogplanet.com/content/six-acoustics-transparent-york-mmmc-phono-preamplifier). Amir gives that preamp a recommendation. ( https://www.audiosciencereview.com/forum/index.php?threads/hagerman-bugle3-phono-stage-review.43069/ ) I know the PS supplied with the Bugle was also a wall wart. (I don't see it for sale on his site anymore, just the PCB.) I have no dog in that fight. I have built Hagerman's designs in the past, and they are solid.

 

[Jim Hagerman]

(I don't see it for sale on his site anymore, just the PCB.)

Indeed. I have upgraded from the BUGLE3 to the BUGLE MC. Same core circuit and performance, but with loading and gain controls moved to front panel, and all in a metal box.