Shouldn't a Phono Stage Be Like a DAC? Why so expensive?

[amirm]

There's always JA...

https://www.stereophile.com/category/phono-preamp-reviews

Oh, I thought since they had stopped measuring turntables, they would not do so with their pre-amps either.

 

[Fitzcaraldo215]

There's always JA...

https://www.stereophile.com/category/phono-preamp-reviews

Hey, great idea. If all you have is a mono system, you only need to buy one at $2k, instead of doubling up.

 

[Cosmik]

Mostly unbalanced technology combined with mediocre specs at exorbitant prices.

You are most definitely keen on the balanced idea! What level of improvement to the objective specs are we likely to see? Do you have a preferred type of technology for this?

 

[jhaider]

Nobody is claiming that you get a statistical outlier for $300; they're claiming you get 'good enough' engineering for $300.

As for a reasonably price statistical outlier, I give you this, for 799 Eur / 999 USD:

-Fully balanced, XLR inputs and outputs
-Dual mono
-RIAA & DECCA curves
-Configurable capacitance & resistance & gain
-Optional battery / disconnected powers supply

And another feature that's useful and hard to find: a power switch!

I've gone through three phono preamps in the last couple years.

The first one was a Rane PS1. The problem with it is that the power supply uses a phone plug, with that little tab that's easy to snap off if you unplug it when not in use. If it had a power switch I'd never have bought another one.

Then came an Emotiva XPS-1. It was fine, and has a regular coaxial power supply plug. I thought it would have more options for MM cartridges, though.

The current one is an iFi iPhono, which I bought because of academic interest in the different compensation curves and the extra loading options. It is not a pretty package though. And you have to unplug it to turn it off.

This Pro-Ject might be the next and last one. It seems to do everything the iFi one does, but it looks much nicer and has a power toggle switch!

 

[watchnerd]

A fine phono preamp...

This Violectric box sports good specs at a reasonable price (€1300):

http://www.lake-people.de/produktdetails/PPA_V600.html

Anyone with same or better specs at a lower price?

That's a very well engineered box, but at $1400 I'd probably opt for the slightly inferior ProJect Phono Box RS for $1k.

My cartridge only costs $700. I can't see spending more on my phono stage than the transducer itself.

 

[svart-hvitt]

You are most definitely keen on the balanced idea! What level of improvement to the objective specs are we likely to see? Do you have a preferred type of technology for this?

The case for balanced topology is laid out here:

http://www.rane.com/note110.html

I think balanced is an example of smart technology.

The turntable is quite vulnerable to noise through the air.

The disadvantage of balanced is thermal noise.

Balanced could be regarded as in insurance against some types of noise. The thing about insurance is you don't know when and if you need it...

Personally, I wonder if some of the cable talk on forums may be due to unbalanced audio. People hear differences, but only due to induced noise somewhere in the audio chain; random, unoredictsble, irreplicable i.e. the perfect food for feeding audio myths.

Let me turn the question the other way around: Why do you think unbalanced audio is an acceptable solution?

 

[Cosmik]

Let me turn the question the other way around: Why do you think unbalanced audio is an acceptable solution?

I don't, necessarily. What I would say is that balanced or unbalanced is a difference of a few cents, or at most, dollars. We are talking about something that is pretty simple!

Someone above mentions the power switch. This, for me, is an example of where engineering excellence comes into play: is your phono preamp guaranteed not to send huge thumps or squeals to the speakers when switched off or on? This actually requires some thought in the design and is, I suspect, one area where eBay circuits will disappoint, as will many of the expensive boutique devices. Mass-produced little units for professional use will probably have the requisite circuitry built in, as will almost all integrated amplifiers - but these are the types of device shunned by the true audiophiles.

 

[svart-hvitt]

I don't, necessarily. What I would say is that balanced or unbalanced is a difference of a few cents, or at most, dollars. We are talking about something that is pretty simple!

Someone above mentions the power switch. This, for me, is an example of where engineering excellence comes into play: is your phono preamp guaranteed not to send huge thumps or squeals to the speakers when switched off or on? This actually requires some thought in the design and is, I suspect, one area where eBay circuits will disappoint, as will many of the expensive boutique devices. Mass-produced little units for professional use will probably have the requisite circuitry built in, as will almost all integrated amplifiers - but these are the types of device shunned by the true audiophiles.

One of the very few "professional" phono preamp I have found is a Sonifex box. Sonifex is big in broadcasting and other pro areas.

http://www.sonifex.co.uk/redbox/rbpa2_ld.shtml

The device costs €350, which could give you an idea of sensible prices for no-nonsense phono boxes of moderate specifications and few features.

It's unbalanced in, balanced out. In my view, this is an intelligent choice if you don't need cartridges with less than 1mV sensitivity (many MC cartridges have less than 0.5 mV sensitivity).

FWIW, Sonifex also has tiny boxes for unbalanced to balanced conversion:

http://www.sonifex.co.uk/cmulx1/index.shtml

http://www.sonifex.co.uk/cmulr1/index.shtml

http://www.sonifex.co.uk/company/logos-images/handbooks/passive_packs.pdf

 

[DonH56]

The disadvantage of balanced is thermal noise.

Not in general, and not theoretically. There are many design trades that can make a similar balanced or unbalanced connection exhibit better or worse performance, but fundamentally a differential stage provides greater SNR by a factor of sqrt(2) compared to a single-ended stage because the signal amplitude is doubled whilst uncorrelated noise (like thermal noise, shot noise, etc.) grows as sqrt(2). That is for a truly differential design; not all designs that claim to be balanced are fully differential.

 

[March Audio]

In my sphere of instrumentation and data acquisition balanced or differential is de facto. Audio is no different in terms of small signal integrity, so why balanced phono amps arent de facto is beyond me.

 

[DonH56]

There used to be a manufacturer that used a mini-XLR or mini-DIN connector (forget which, ages ago) to maintain balanced from the cartridge through the TT to the preamp. Makes sense to me. My guess for "why not" is cost and complexity (which also leads to higher cost, natch) plus history (difficulty of change). Since the vast majority are not balanced, they get away with it, and until TT manufacturers mount a balanced connector from the cartridge there is no incentive for preamp designers to change.

 

[watchnerd]

In my sphere of instrumentation and data acquisition balanced or differential is de facto. Audio is no different in terms of small signal integrity, so why balanced phono amps arent de facto is beyond me.

I got into a lengthy online debate at Head Fi with Mike of Schiit over this when I suggested they make a balanced phono amp; he was arguing that it made no sense, was totally unnecessary, was an act of intellectual masturbation, etc.

I persisted until they basically threatened to use the moderator tools unless I shut up about it.

 

[svart-hvitt]

There used to be a manufacturer that used a mini-XLR or mini-DIN connector (forget which, ages ago) to maintain balanced from the cartridge through the TT to the preamp. Makes sense to me. My guess for "why not" is cost and complexity (which also leads to higher cost, natch) plus history (difficulty of change). Since the vast majority are not balanced, they get away with it, and until TT manufacturers mount a balanced connector from the cartridge there is no incentive for preamp designers to change.

Here are two manufacturerers with balanced 5 DIN/mini 5 pin XLR in:

http://www.lake-people.de/produktdetails/PPA_V600.html

http://www.musicalfidelity.com/mx-vynl

Pretty practical, I think.

 

[DonH56]

Yup. What TT manufacturers have balanced connectors? Some must have for the preamps to have the input... In The Ancient Days I modified a few TTs and transformers for balanced I/O, and built up a little balanced preamp, but I have no idea what TTs have balanced connectors now.

 

[svart-hvitt]

Yup. What TT manufacturers have balanced connectors? Some must have for the preamps to have the input... In The Ancient Days I modified a few TTs and transformers for balanced I/O, and built up a little balanced preamp, but I have no idea what TTs have balanced connectors now.

Don, in some designs the tonearm cable is loose, i.e. not fastened to a set of connectors on the back of the player.

And the new Thorens have 2 normal XLR out:

https://www.thorens.com/en/td-907-en.html

 

[DonH56]

Interesting, thanks. Hopefully they didn't short the negative and shield of the XLRs by directly hooking up the RCAs.

Pretty sure someplace in the black hole masquerading as our basement (or maybe out in the one masquerading as our shed) I have some machined plates for Linn and a couple of other TTs that replace the standard RCA plate with a pair of mini XLRs or a DIN jack. Way back when I was able to finagle a friend to machine me a small stack of them at nominal cost (might have been beer, but I have a vague memory it was Jack Daniels Black, pricey little bugger ).

 

[svart-hvitt]

Interesting, thanks. Hopefully they didn't short the negative and shield of the XLRs by directly hooking up the RCAs.

Pretty sure someplace in the black hole masquerading as our basement (or maybe out in the one masquerading as our shed) I have some machined plates for Linn and a couple of other TTs that replace the standard RCA plate with a pair of mini XLRs or a DIN jack. Way back when I was able to finagle a friend to machine me a small stack of them at nominal cost (might have been beer, but I have a vague memory it was Jack Daniels Black, pricey little bugger ).

Impressive you demonstrated such foresight, experimenting with balanced decades ago.

I just can't understand why so many vinyl people experimenting with cables (silver, cooper etc etc) are so openly hostile to balanced turntable tech (cfr. watchnerd's experience, and my own, I may add).

Frankly, I guess I wouldn't at all be able to distinguish unbalanced vs balanced (as long as ground loops are not a big problem) by hearing... My point regarding balanced is more an intellectual one: Why settle for technology where uncontrollable factors could sneek in and distort the picture? Why take the chance?

I like technology that is well thought out, even if it costs a bit more.

 

[March Audio]

I got into a lengthy online debate at Head Fi with Mike of Schiit over this when I suggested they make a balanced phono amp; he was arguing that it made no sense, was totally unnecessary, was an act of intellectual masturbation, etc.

I persisted until they basically threatened to use the moderator tools unless I shut up about it.

Then he has no idea what he is talking about; and differential input is not esoteric, difficult or expensive to acheive.

Why is it that proven standard techniques in other electronic engineering spheres go out the window in domestic audio electronics?

 

[watchnerd]

Then he has no idea what he is talking about; and differential input is not esoteric, difficult or expensive to acheive.

Why is it that proven standard techniques in other electronic engineering spheres go out the window in domestic audio electronics?

The debate centered on whether the cartridge itself was inherently balanced (I was in the 'yes' camp):

https://www.head-fi.org/threads/what-a-long-strange-trip-its-been-robert-hunter.784471/page-108

 

[March Audio]

The debate centered on whether the cartridge itself was inherently balanced (I was in the 'yes' camp):

https://www.head-fi.org/threads/what-a-long-strange-trip-its-been-robert-hunter.784471/page-108

It really shouldnt be up for debate in terms of the benefit of differential input for noise and cmr.

Did no-one mention microphones and their cabling and pre- amps? no- one objects to differential there.