GoodSoundClub - Romy the Cat's Audio Site - The last phonocorrector: “End of Life" Phonostage

06-17-2015

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Romy the Cat

Boston, MA
Posts 10,155
Joined on 05-28-2004

Post #:	281
Post ID:	21716
Reply to:	21715

The Thorsten’s mark.

Yes, Thorsten was the man that made the initial modification in the EAR 834 and I need to note that it was not redesign of any kind but juts basic modifications and admitting the unnecessary things. Even though Thorsten is the industry person he did not play any game sand posted his write up open and public. My contribution to the projects was supplementing the EAR 834PT (“T” comes from Thorsten) with no dielectric capacitors (air caps) and bounding it with ET-2 transformer that make great phonostage to be “End of the Life” phonostage. I do not particularly care about my priority in this process as I do audio for MYSELF. All of those industry idiots do not get that for a person who does audio excessively for own needs all their stupid self-pomposity is very much irrelevant and their pretentiousness screaming is just a noise to me.

Still, do not discard behind the stupid TdP behavior the elegance of 834 TdP’s design and the quality of 834’s sound. > >

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

01-30-2017

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N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	282
Post ID:	22933
Reply to:	16916

Sound beats engeneering

Romy the Cat wrote:
fiogf49gjkf0d1)

3) The common mode filter you have at the PS’s input- why do you use them? They do eat some dynamics. As many time I removed them from all imaginary components as many time I witnessed better sound.

After a long break I'm slowly comming back to my system. Only now I've found the time to check that and I must agree with Romy: Removing CM filters, MOVs, arresters the rest of the engeneering crap (apart from the hour meter) from the power lines has cleaned the sound, its more emotionally involving, direct, the dynamical contrast does seem better. The change was rather subtle but noticeabe, in a bit similar direction as my experiments with vibration decoupling- some subtle veil got removed.

Cheers,
Jarek

Cheers,
Jarek
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01-30-2017

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Paul S
San Diego, California, USA
Posts 2,656
Joined on 10-12-2006

Post #:	283
Post ID:	22935
Reply to:	22933

Engineering Crap

Yes, an ongoing theme here at GSC: If it sounds good, it is good. Conversely, no matter the "logic", and no matter the "technical genius" or "technological breakthroughs", if it sounds bad, it is bad. Likewise with any sort of "logic" or "intuition" that is not actually borne out by acceptable sound: it is not good. The problem with the empirical/subjective method for audio is mainly time/money, also the Big Problem that the listener's tastes are required to make the judgement calls in the first place. Of course, this is antithetical to most engineer's ideas about who they are and what they and their ilk stand for; hence the discussions on their forums vs. here at GSC.

Best regards,
Paul S

01-30-2017

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N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	284
Post ID:	22936
Reply to:	22935

Its not that it sounds "better"

it's more similar to removing say some delicate wool from your ears. I guess some recordings benefited from a bit of the veil but then its a problem of the recording.

Paul S wrote:
also the Big Problem that the listener's tastes are required to make the judgement calls in the first place.

In this case I hear an increased recognition of low level details (e.g. when musicians take air in your hear it as taking air in), which
I'd promote to sth more objective than just down to the taste. Anyway, vinyls kept spinning.

Cheers,
Jarek

Cheers,
Jarek
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06-17-2018

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N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	285
Post ID:	24939
Reply to:	22936

Burn, motherf....r, burn!

t took me 5 freaking years to fin-anally install a second set of SUT's in my EAR834. 4 out of those 5 years was waiting for Tribiute Pieter to make me custom silver SUT's on nanocrystaline core. I even found him the wire. I went boutique and the new input path is silver WBT, Pieter AG SUT's 1:12, silver wireing from Neotech (the blue cables) and a TKD switch. After bitching at German mafia I finally went their way too as it's the only switch with a solid silver contacts. The switch was Paul S treated with all the contacts polished and protected with a dielectric grease (Paul I hate you for teaching me this procedure - it's such a pain). Now the path is being burned in. I found an ingenious way to do it: inject the signal (Hagtech's frybaby) to the input tube's socket and close the circuit with some 6.8R resistors at the headshell. This way all the path is current loaded including the tonearm wiring and the tonearm cable. 10 more days of burning (due to travels) and I try it! It will serve for a FR64S+Fr7f combo, connected by AQ Leopard.
And who wins the prize for the least optimal layout? Meee!
Cheers, Jarek

Cheers,
Jarek
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01-23-2020

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AlexBerger
Israel, Beer Sheva
Posts 20
Joined on 04-19-2010

Post #:	286
Post ID:	25764
Reply to:	24939

Bypass Schottky by Snubber

Hi,
I have the phonostage with the similar schematics that Romy has.The power supply use SiC Schottky diodes in bridge and 15H choke load exactly like on the scheme in this thread.Is it possible to bypass each Schottky diode by 10-100 pF capacitor?Does it work with a choke load power supply schematics?
Regards,Alex.

03-15-2020

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N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	287
Post ID:	25789
Reply to:	25764

Snubbers

Alex, why do you think you need them? I've never experimented with snubbers at the SiC's directly. I only put two input caps right after the bridge and a dropdown resistor which I use before the input choke. IIRC the value is 10nF/1500V. This released some stress from the input choke and quieted it. If you want to play with snubbers, there is a great article by Hagtech on how to calculate them:
http://www.hagtech.com/pdf/snubber.pdf

Cheers,
Jarek
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03-15-2020

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N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	288
Post ID:	25790
Reply to:	25789

More on snubbers

I was digging in my archives, trying to find what exactly input cap I've put and how. Didn't find that. IIRC I've put two, in V configuration, one output of the HV bridge to mass, another exit of the HT choke to mass. Found some traces of voltage at my HV choke showing the efficiency of the snubber. Here is the voltage without the snubber:

And with the snubber:

You can see how it gets rid of the ugly glitch.

Cheers,
Jarek
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03-15-2020

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N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	290
Post ID:	25792
Reply to:	25791

Capacitors & updates

I think industrial grade Arcotronics KP172 (from RS components ?), film and foil. I use them also as output coupling caps (2x0,47u)

Other changes I've made, not commented in my posts here:

- installed an all silver TKD switch (230GBP!) to switch 2 SUTs (silver and copper Tribute) + MM; don't remember noticing any sound change before and after
- changed loading resistors from Dales RN60D to Charcroft Z-foils; I fist burned them in for several days; this was quite a change - immediately increased transparency and better discrimination of tonal nuances, v nice! the loading resistors are on the SUT primary as this sounded IIRC a tiny bit more open and involving compared to secondary or split loading (Dave Slagle has as interesting post on that, which motivated my experiments)
- changed the input regular Tlf 12AX7 to selected red tip Tlf 12AX7 and the 2nd tube to selected low noise Sylvania 7025 (both from Brent Jesse); as far as I remember there was again increase in transparency but not as much as changing the loading resistors; have to dig out in my notes
- the power cord is DIY according to Paul S recipe with ebay Chinese pure coper plugs; now you can laugh: changed the fuse to russkie silver one; *both* changes again opened up the sound a bit

Other changes to come:

- looking for Amperex 0A2 with mesh plates
- will rewire MM input in silver with silver WBT RCA's - it now welcomes my top cart, Decca London Reference with silver AQ Leopard phonocable (will post on that in a separate thread)
- considering another red tip 12AX7 for the output but given the change was not big at the input it's more of an itch...a costly one at $275

Cheers,
Jarek
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03-15-2020

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AlexBerger
Israel, Beer Sheva
Posts 20
Joined on 04-19-2010

Post #:	291
Post ID:	25793
Reply to:	25792

Z-foil

Do you use input 50KOhm Z-foil resistor between input tube greed and GND?Does Z-foil sound colder compared to Dale RN60D?U used Dale before. Now I use Shinkoh tantalum resistor. It has similar to Dale tonal balance but sounds smoother.I heard a lot of good things about Z-foil resistors. But people say they have more cold and analytical sound compared to Dale and Shinkoh.
I also can recommend to you, Audio Note RCA silver plated sockets. One my friend compared them to WBT and prefered AN.I tired AN RCA sockets and preferred them to Vampire Copper that I previously used. Compared to Vampire AN sounds more open and vivid and they still have a good bass, mids and natural tone.

03-15-2020

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N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	292
Post ID:	25794
Reply to:	25793

Loading resistors & sockets

Alex, as I wrote I use Z-foils at the primaries of mu SUT's. I'm not sure if colder is the world *I* would use. I'm after immediacy and transparency and this is what they gave me. Also widening tonal discrimination, hearable esp with solo piano. My personal bias is against smookey rounded sound with veiled details.
Sockets - thanks but got already WBT's and are burning them in together with input Ag wiring, don't really want to go into sockets craziness again. Have been there Smile

Cheers,
Jarek
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03-16-2020

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N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	293
Post ID:	25795
Reply to:	25792

Low noise tubes

N-set wrote:

- considering another red tip 12AX7 for the output but given the change was not big at the input it's more of an itch...a costly one at $275

After a second thought actually the output tube is obviously in the feedback loop too, so perhaps changing it to low noise has more merit than just an audiophile itch.
Also contemplating changing the 750K feedback resistor from Dale to Z-foil.
Any thoughts?

Cheers,
Jarek
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03-17-2020

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Paul S
San Diego, California, USA
Posts 2,656
Joined on 10-12-2006

Post #:	294
Post ID:	25796
Reply to:	25795

What Works Where

The "funny" thing is, the part that "sounds the best" in one situation might not do as well in another situation. A great example I can remember is the fabled Vishay S102 resistor at the grid. Great for stepped attenuators; not good at all at the grid. The only way to find out is to try it. Likewise, some of the favorites have "sonic signatures", and it is possible (IMO) to get too much of something one "likes". I think this got pretty well talked to death in a capacitor thread, years ago.

Paul S

03-17-2020

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rowuk

Germany
Posts 454
Joined on 07-05-2012

Post #:	295
Post ID:	25797
Reply to:	25795

What are the REAL goals?

I find the fascination of boutique parts amusing. In the case of vintage tubes, using them is a guarantee that one day you will never be able to replace them. In my world, I want to optimize with „sensible“ parts, maybe even stockpile some extra tubes. I have never thought of a 12AX7 to be a great output tube, simply because of its high impedance (and thus sensitivity to loading/cables).
I really wonder how often the „rest“ of the system including source and setup is „good enough“...

Whenever I feel blue, I start breathing again.

03-17-2020

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N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	296
Post ID:	25798
Reply to:	25797

Good engineering parctices

I'm wondering if Romy experimented with the feedback resistor quality. His ingenious contribution to the design was to use the purest caps possible as in the feedback loop every imperfection gets amplified. So the next logical step after caps would be the resistor. I admit I'm a bit lazy here as changing anything in my layout costs quite some work.
Rowuk - in my world low noise selected tubes and ultra low noise resistors in crucial positions are a good engineering practice not a high end boutiqueness. Both z foils and red tip Tlf tubes come from medical/scientific equipment, not high end. The goal? You remember the touch of music on your cheeks that was not the air conditioning? Let's call it the goal.

Cheers,
Jarek
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03-17-2020

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drdna
San Francisco, California
Posts 526
Joined on 10-29-2005

Post #:	297
Post ID:	25799
Reply to:	25796

Physical attributes of devices matter

Every resistor, capacitor, tube, etc. are just physical devices that are optimized to come a bit closer to an ideal device -- a wirewound resistor may represent an ideal resistor, but it has inductance, capacitance, and other electrical and physical properties. All these properties have an impact on the circuit design. When one brand or type of device seems to "work better" in a certain position or application, it's related to how well it compensates for and interacts with the devices it is connected to. The goal is to get the overall circuit to closely approximate the ideal circuit on your schematic diagram to transmit your musical signal.

Understanding and keeping in mind how the devices that we select deviate from an ideal form (and what compromises are acceptable in a particular location in a circuit) helps to guide device choice. Listening tests are always important, and should serve to instruct us on our understanding of these compromises.

Adrian

03-17-2020

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rowuk

Germany
Posts 454
Joined on 07-05-2012

Post #:	298
Post ID:	25800
Reply to:	25798

The idea that the sum of the parts "quality" offers the best sound is flawed

We cannot view theoretical advantages of individual parts as the path to a better solution. The EAR phono corrector worked so well because the total concept was holistic. Thorstens modifications did not use the "premiere" parts to get the total solution. Even Romys solution was not a parade of lowest noise or highest specs. It was a holistic solution reached through experience and listening.

While "noise" could be a factor, I would consider the Sound and sound density to be a more worthy goal.

My "touch of music" will never be found with a hardware solution.
I disagree that imperfections always get amplified. In properly designed equipment, we leverage the sum instead of searching for the biggest numbers. We cannot decide if something is "more perfect" out of context.

Whenever I feel blue, I start breathing again.

03-17-2020

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Romy the Cat

Boston, MA
Posts 10,155
Joined on 05-28-2004

Post #:	299
Post ID:	25801
Reply to:	25798

It was 13 years back...

Yes, of cause I have experimented with the resistors quality. The way how the resistor is used in the feedback loop in my view make is less relevant. The feedback resistor is applied to high impedance source that make less signal to flow other the resistor. Also it is shunt resistor… The idea to use the “purest caps possible” come from the fact the in a capacitor the repolarization of dialectic is a problem and each dialectic has own residual polarization and own sonic signature. In some cases it is not important and the dialectic is full biased with DC voltage. In coupling caps for instance while the stage in class A1. In feedback there is no DC bias and AC constantly repolarize the feedback caps. Them then to repolarize air instead of a dielectric.

The loading R3 resistor is super critical for sound, so the cathode restores. I did not experimented with the resistors quality in this given feedback. Any resistor that you trust should go well in this application. I think I used Dale RN-55 or 60. I do not know how they are nowadays. The quality of those things is going up and down and what I did was 13 years back… I heard that some brands that I used to know and tested by me went down sound-wise very dramatically. So, I do not know what is going on now out there…

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

03-17-2020

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N-set
Gdansk, Poland
Posts 617
Joined on 01-07-2006

Post #:	300
Post ID:	25802
Reply to:	25801

Thank you

Romy, that's sort of a feedback I was hoping for, thanks. Ok, I see the point, with the feedback and R3 resistors. The last loads the loop. I have now there 1W Dale RN65D, guess Z-foils with their 0.25W dissipation won't work.
And what is your view on using selected low noise tubes? I have now such low noise Telefunken at the input and low noise Sylvania 7025 in the 2nd stage. Honestly they didn't produce much change wrt normal Tlf 12AX7 and 7025 but I still contemplate changing the output tube to low noise Tlf too. Motivating again by being in the loop. It's quite expensive though at $275.

Cheers,
Jarek
STACORE

	Target	Threads for related reading	Most recent post in related threads	Forum	Replies	Views	Started
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	Target	Threads for related reading	Most recent post in related threads	Forum	Replies	Views	Started
»	New	Where are our good phonostages?..	Omnigon Tubes...	Analog Playback Forum	61	665066	05-31-2004
»	New	The Expressive Technologies SU-1..	“too bright” or “resolution” or “details” with SUT prim...	Analog Playback Forum	33	375956	12-30-2004
»	New	EAR 834P Modification Guide..	The cap will not change volume in the pass band...	Analog Playback Forum	45	638822	02-09-2006
»	New	My Analog Playback: the fat lady has sung..	My analog setup update....	Analog Playback Forum	9	119405	04-04-2006
»	New	Phono stages with SU-1..	SU-1...	Analog Playback Forum	4	66052	11-23-2007
»	New	Chasing utopian better phono interconnect...	Did I miss something?...	Analog Playback Forum	6	110826	06-05-2008
»	New	Buying a last cartridge...	Lucky you...	Analog Playback Forum	80	809909	09-05-2008
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»	New	AMR PH-77: just another phonostage or more?..	Oh, yeah... the sound of the Thing Itself......	Analog Playback Forum	11	132263	07-05-2009
»	New	An interesting Russian pnonocorrector...	Uber-tweeky phono topologies deconstructed...	Analog Playback Forum	9	99273	03-01-2010
»	New	Expressive Technologies SU-1 and cartridge output and i..	MV and Ohms...	Analog Playback Forum	2	33597	07-07-2011
»	New	How to run MM-type cartridge into MC phonostage?..	Quite interesting....	Analog Playback Forum	6	67315	11-13-2011
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