GoodSoundClub - Romy the Cat's Audio Site - About EAR 834P Modifications

12-13-2008

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Romy the Cat

Boston, MA
Posts 10,184
Joined on 05-28-2004

Post #:	26
Post ID:	9154
Reply to:	9153

Interesting how you found the 834PT

Very good! It is very interesting how you will find the 834PT. Even in stock version (but with OK tubes) I found it demonstrate some interesting qualities. Do not use the 834PT output attenuator of you have one on the unit and make sure that the needle is loaded properly. The stock 834PT I belie come at 47K. I do not know your Decca cartridges but if they are MC and have high output then they shell have a LOT of wire on them and therefore might have very high impedance. So, it is most likely that 47K will work out for Decca. Still it is very simple to change the loading resistor to whatever you to.

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

12-14-2008

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

Post #:	27
Post ID:	9155
Reply to:	9154

OK Tubes?

Romy the Cat wrote:
Even in stock version (but with OK tubes) I found it demonstrate some interesting qualities.

So you do not recommend the stock tubes? Is it a specific change you recommend?

Romy the Cat wrote:
I do not know your Decca cartridges but if they are MC and have high output then they shell have a LOT of wire on them and therefore might have very high impedance.

Decca cartridges are not MC or MM. The stylus attaches to a thin flexible foil directly flexing in a magnetic field. There is no cantilever. The total moving mass is thus greatly reduced. Very dynamic, very musical, very detailed, but most importantly it has the hard to obtain "unpredictable" live sound.

Adrian

12-14-2008

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Paul S
San Diego, California, USA
Posts 2,672
Joined on 10-12-2006

Post #:	28
Post ID:	9158
Reply to:	9155

Your Own Tube Lore

Adrian, I wonder how you wound up with the never-mentioned FET 10? FWIW, it was one of the better all around phono stages I've heard, and - not that it matters - I prefer it to the EAR 834 I heard. Is this another case where it's full of old caps? I would not be at all surprised if futzing with those caps might yield as many benefits as playing with tubes, etc. in another phono stage.

I thought the point of selecting tubes is to use those that most closely meet your own requirements, since it's a given that they do not all perform alike. The best I have been able to do is to get a basic idea of which tubes to avoid or which might be candidates to try for any given, system-dependent application. Then, I pay my money, and I simply take my chance.

Meanwhile, the more "clear" my own phono stage has become, the more obvious the differences between tubes has become; and not just by make and model, but also sample-to-sample differences. And, just to further confuse the matter, I wound up going back to a "more clear" tube in the K & K after I broke in the "double twister" IC, which had the effect of dropping the system balance a little. I also wrote about my own most recent "interesting" experience with tubes (in the ML2 thread), when a new pair of input tubes gave me "the best sound to date" -- apart from a disappointing cut in harmonics, compared to the otherwise-lesser tubes. Basically, it's proven to be yet another hi-fi pisser that tubes - even "good" tubes - are just another annoying variable. And if we're talking [potentially] "good" 12AX7s, then we're talking yet another expensive variable/pisser.

Best regards,
Paul S

12-14-2008

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Romy the Cat

Boston, MA
Posts 10,184
Joined on 05-28-2004

Post #:	29
Post ID:	9159
Reply to:	9155

834P re-tubing.

drdna wrote:
So you do not recommend the stock tubes? Is it a specific change you recommend?

Better tubes will certainly give you better sound, in many cases more sophisticated sound. I do not know what tubes EAR uses as stock tubes nowadays, they might be acceptable. I bought my EAR near 10 years back, in London, and it came with EAR’s own rebranded Chinese tubes. They were OK but not great and there were a lot much better options.

The subject of 834P re-tubing is well coved elsewhere, with all expected candidates. I usually hesitant to give any recommendations for “improvement” if a request does not contain any defined and specific complain about the current results.

The Cat

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

12-14-2008

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

Post #:	30
Post ID:	9160
Reply to:	9159

Tubes in the 834p circuit

Romy the Cat wrote:
I usually hesitant to give any recommendations for “improvement” if a request does not contain any defined and specific complain about the current results.

Naturally, this makes sense. My question was actually specifically about the choice of tubes for the EAR 834p topology. Since we both deal with EAR 834p in context of high efficiency horn loudspeaker system, I thought it might be interesting to see if you thought any specific tube was well suited to this application or just "any" good tube is fine.

Smile

Adrian

12-14-2008

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

Post #:	31
Post ID:	9161
Reply to:	9158

History of phono stage

Paul S wrote:
Adrian, I wonder how you wound up with the never-mentioned FET 10? I prefer it to the EAR 834 I heard. Is this another case where it's full of old caps? I would not be at all surprised if futzing with those caps might yield as many benefits as playing with tubes, etc.

Ha ha. I have had the FET-10 for more than 20 years. I got this and SA-3 amplifiers from Nelson Pass when he still owned Threshold. Everything with various modifications with capacitor changes, wiring changes, etc., but the greatest benefit was coupling to a passive line stage, making the FET-10 phono stage especially magical sounding. Every other phono stage I have purchased or borrowed has inevitably left and the FET-10 has remained, however, I have never heard the EAR 834p. We will see.

Paul S wrote:
Meanwhile, the more "clear" my own phono stage has become, the more obvious the differences between tubes has become

Why would the circuit be becoming more sensitive to tube choice? I wonder if it is something about the toplogy?

Also Paul, you have clearly heard EAR 834p and the FET-10 in your system apparently. I believe you now have the K&K. I would be instructive to hear your thought on these different units, primarily to have more insight into how you listen. I will at some point make my own comments on the comparison of EAR 834p and FET-10 and we can then see if we listen in a similar way or not. I believe you know my suspicion, based on my theory of human listening.

Adrian

12-14-2008

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Romy the Cat

Boston, MA
Posts 10,184
Joined on 05-28-2004

Post #:	32
Post ID:	9162
Reply to:	9160

It might be used whatever you wish in the 834P

I have seen people use 12AU7, 12AT7, the circuitry might be tweaked and it will accept anything. I use a 7025 in second stage (look into the linked thread “Once more unto the phonostage dear friend!”). Hey, I even used a transistor as follower! I know Dima has instead in input stage a nuvistor… We also run 2-stage vision of 834P with pentode 7788 in fist stage. So, anything will work in there if the circuit is properly adjusted for the given tube/s. How will it all to Sound is another story…

The 12AX7 is very common tube. If you do not have a stash of your favorite 12AX7 tubes (like none of your electronics use it for instance) then I would not urge to run and to pay $200 for a 3 good 12AX7 but use whatever 834P comes with. Since you are just trying it then it is good idea to borrow the good tubes from some of your local guy.

BTW, the 834P is quite sensitive to electricity that is able to destroy it’s sound much more then bad tubes…

The Cat

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

12-14-2008

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Paul S
San Diego, California, USA
Posts 2,672
Joined on 10-12-2006

Post #:	33
Post ID:	9165
Reply to:	9161

The Power of Imagination?

Sorry, Adrian, I did not hear either phono stage in my present system, nor did I A/B them, but I "compared" them in my "aural memory", with the actual listening sessions spaced several years apart. Back around the time of the FET 10, maybe a little before, Berning also put out a couple of units (TF10/TF12, I think) that could also be made to sound pretty good. Then everything got worse for a long time. When the FET got old enough that I could afford one, I wound up buying the AI M3A, which gave me the impression it could be a world-beater... if... and I got caught up in modding it for years, until I found a hot-rodded hair-shirt K&K that someone else had already done most of the work on. That was a lucky stroke; it was a nice change to have so little to do to dial the thing in! I have already written lots about the K&K in its own thread, and I will be happy answer questions about it there.

I heard the 834 compared to a Klyne in someone else's system. I did not wind up wanting it like I did the FET. I found the 834 to be somewhat thick, congested and slow, not special, and not just compared to the Klyne, which went too far the other way, especially with the big B&W speakers. I heard the FET with big Fulton speakers (very good, actually, just not efficient). I thought the FET had very good range and wonderful balance, and I do not mean that as faint praise. We tried two different cartridges and it made their differences and the weaknesses and strengths of each quite clear without creating "issues". Early MOSFET stuff was pretty fuzzy, and there was none of that. It was basically neutral without being boring, which I think is swell and all too rare; a good beginning, at the minimum. The best Fultons could do color as well as any speakers I have ever heard, and the FET made them sound alive on that level, and the same with that very rare "relaxed" low-level detail. I really wanted one, but at the time they were too expensive. Then, they all just disappeared.

Best regards,
Paul S

12-15-2008

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Paul S
San Diego, California, USA
Posts 2,672
Joined on 10-12-2006

Post #:	34
Post ID:	9172
Reply to:	9161

Sensitivity Training

I would not say the circuit (per se) was becoming more sensitive to tube choice (and neither would I claim it's not...); I would say that as I have developed the system I have been better and better able to hear what more and more pieces in the system-wide "circuit" are doing, including tubes, so it's no longer just a matter of choosing tube type but it has also proven worthwhile to select particular tubes, according to the audible effect they have, within the system. Rather like VTA (or IC), actually. But I've had this problem for years, and I think lots of other people also have this gift/curse. And I'll bet lots more people still could develop the gift/problem if they just listened "consistently" with any kind of objectivity, let alone any idea of what music actually sounds like, and they went and paid attention to where their ears and taste took them. I see this as similar to (but not the same as) "spice-ing" the system, except the different tubes seem to have somewhat "deeper" effects than IC (once you get past the obvious dreck, of course). And, like Romy said, I don't see what difference any of it makes in a phono stage if the electricity is not primo. Really, I think it's just simple fooling around to swap phonostage parts unless the electricity is primo and one has good targeted listening skills.

It would be funny to find out it's true, but I would not be surprised if the FET 10 and the K & K sounded more alike than different, and certainly more alike than my K & K and the 834 I heard. How would that be explained by topology? I mean, go figure. Or the Boulder's "limitless" thing... from freaking op amps? What the hell is that?

Again, I am interested to see what might come from the "which-component-in-what-topology" theory, but my inner Raymond Lull always winds up rearing its head, and I can't help but think that the actual matter is considerably more complicated - arcane, even - and not so easily nailed down, in practice.

Best regards,
Paul S

11-24-2009

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valves
Posts 2
Joined on 11-24-2009

Post #:	35
Post ID:	12346
Reply to:	2071

Modification to the Ear 834P

Hello to everyone, am new to the sight. Been reading for a while and decided to mod my 834. I've had the unit since '96, purchased new from the local dealer. I have noticed a few differences from the schematic, the 220K load resistors R10 and R110 are absent. Following the coupling caps are jumpers labeled P2 and P102 to traces in the circuit board. Following the traces to the center of the board, there is a 100 ohm resistor in series with each coupling cap R18 and R118. Both traces seem to be connected to 47K ohm resistors R17 and R117, there also are two, 10K ohm resistors in the same area R19 and R119. Does any one know what the purpose of these resistors is for? Do I need to add in the 220K ohm resistors? None of the above resistors are on the schematic provided with the 834 or on the schematic on the web sight. Also would someone be kind enough to chime in with some recommendations for coupling caps. Space provided is tight. Just curious as to what other users find to be the best in the coupling positions. Thanks in advance, Valves

11-24-2009

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Romy the Cat

Boston, MA
Posts 10,184
Joined on 05-28-2004

Post #:	36
Post ID:	12347
Reply to:	422

To keep the Ear loaded.

valves wrote:
Hello to everyone, am new to the sight. Been reading for a while and decided to mod my 834. I've had the unit since '96, purchased new from the local dealer. I have noticed a few differences from the schematic, the 220K load resistors R10 and R110 are absent. Following the coupling caps are jumpers labeled P2 and P102 to traces in the circuit board. Following the traces to the center of the board, there is a 100 ohm resistor in series with each coupling cap R18 and R118. Both traces seem to be connected to 47K ohm resistors R17 and R117, there also are two, 10K ohm resistors in the same area R19 and R119. Does any one know what the purpose of these resistors is for? Do I need to add in the 220K ohm resistors? None of the above resistors are on the schematic provided with the 834 or on the schematic on the web sight. Also would someone be kind enough to chime in with some recommendations for coupling caps. Space provided is tight. Just curious as to what other users find to be the best in the coupling positions. Thanks in advance, Valves

I moved you post to the thread where it is belong; I hope you do not mind. I would not comment upon coupling caps as it would look as “recommendation without context”, something that I do not practice at my site. Regarding the R10 resistor, yes, keep it. This resistor is a bleeder – it discharges the output cap. If it has a significantly high volume, like 100K-300K then it has no impact when the corrector is running. However, when the corrector is off and there is no bleeder after the out caps then switching the corrector cables might create loud clicks. So, the R10 resistor is an assurance that the output cap will always loaded. It has no impact to sound of the corrector.

The Cat

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

11-24-2009

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valves
Posts 2
Joined on 11-24-2009

Post #:	37
Post ID:	12348
Reply to:	12347

Bleeder resistors.

Thanks for the reply. My 834 came from the factory without the 220k ohm resistors. I was wondering if I should go ahead and add them while I still have the unit apart. I purchased Caddocks for the repalcements but alas no where to put them without adding a few holes in the board, or maybe some other kind of bandaid. Also curious as to the other 6 resistors R18 and R118, R17 and &117, and R19 and R119. The last four seem to be connected to the output traces and ground. None of these resistors are on the available schematics, I may be parting hairs here, just wondered what I leave them in or take them out, Thanks again, Valves

12-03-2009

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Romy the Cat

Boston, MA
Posts 10,184
Joined on 05-28-2004

Post #:	38
Post ID:	12412
Reply to:	422

Martin Ruppel’s assault on EAR834P

I do not read German but here is another renderation of my 834P

http://www.jogis-roehrenbude.de/Leserbriefe/Martin-Ruppel-Phonoamp/MRuppel-Phonoamp.htm

I do not know what Martin ended up with and how it sound. It looks like he use huts MM needles. Still, the pictures are self-explanatory…

The Cat

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

03-28-2020

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Taso
Posts 1
Joined on 03-28-2020

Post #:	41
Post ID:	25809
Reply to:	22573

Caps infos

hello guys, greetings from Italy !! ..I would have a question being that they are still being optimized.

I have to buy the 6 caps that are on the PCB valves .. those at 400-450v.

On my ear..which I bought on ebay..they were self-built by a fan..the 100uf 400v caps were mounted..Sanwa brand, SD..85 ° series .. and I would say very normal.

Since I have a doubt about their state of health ... I avoid explaining why ... I was about to buy another 6 ... to assemble.

I would have found some Kendeil .. K05 series..a great price..I can choose between 100uF 450v or 220uF 400v..all 105 °.

I'm also finishing to solve hummm problems .. which are not however given by any mass loops .. those I have already fixed for good ... having excellent results.

I was wondering ... I was asking you..so .. if you buy back 100uF .. Kendeil..o if you switch to 220uF.

I would not, however, with such a higher capacity ... create noise problems .. overload diodes .. in short .. what I am looking for is exactly the opposite ... or improve something!

On some forums .. also on this ... I see in some photos that, for a fee, one cap, 4 caps are the same .. I don't know the value however .. but the other two are bigger .. I think the ones near the valve V1 or V3.

anyway give me some advice? while I buy them .. if I can benefit from them ... I would go to 6 x 220uF ... or maybe .. if I had to follow the photos I see on some forums .. put 4 of 100uF and 2 of 220uF ... even if not I know where the big two go !!

The fact is also that it seems to me that the original ear mounts 6x22uF ... and that the Chinese kits provide 6x47uF.

I point out that I have also redone the power supplies .. both anodic and filaments .. if you want to place the pattern and give me an opinion. maybe it can be useful to someone.

Thanks !!! and sorry for my english

03-28-2020

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rowuk

Germany
Posts 454
Joined on 07-05-2012

Post #:	42
Post ID:	25810
Reply to:	25809

Already done

Thorsten Loesch who came up with the mods, details what caps and why on the first page of this thread. Lacking interest for multiple years of auditioning caps, I just built it that way (2012 or so) and have had no urge to change anything. Romy has pictures and details of his mods.
"Change over C8 and C9 to larger value, "known good" sounding electrolytics, I'd be tempted to specify at least 100uF/385V Nippon Chemi Con (radial leads) VX series, these will be a VERY "tight fit". Also find a way to bypass them with at least 0.47uF Wima MKP04 or better (tight fit again). You could use Black Gates again, or Elna Cerafine if you can find them, the Cerafines I quite like, the Black Gates I don't like that much.

If I'd build another unit from scratch I would use a pair of Ansar
Supersound 32uF + 32uF 400V, but these are 4" long and 2.5" in diameter, no way you get them inside the original EAR case. And they cost around 50 Bucks each too.... ;-)

They are available from Cricklewood Electronics in London, you'll have to e-mail them for details.

http://www.cricklewoodelectronics.com/

If you modify an existing unit retaining the on-board supply change D1 & D2 to soft switching, superfast types and place a 100 Ohm 2W Resistor between the transformer HT secondary and the Diodes.

In a scratch build unit I actually would/do use a 240-0-240V Mains transformer and a Valve Rectifier (6X4/EZ90 or 6CA4/EZ80/EZ81), and make two electrically independent supplies, with the HT Rail in the EAR split up between the channels, so that C8 and C9 doubled up, R13 doubled up but changed to 200/220K per channal and R14 doubled up and changed to 20/22k per Channel."

Anything else that you do that is different will be "different". I do not believe most of what is written online. "People" are too willing to prove how knowledgable that they are and you find out the hard way that their level of "hearing" is not good enough to back up their claims (if they even did what they post).

I would suggest not reinventing the wheel. Either duplicate the efforts of someone else or return your device to the original state. If you are using one of those DIY kits, all bets are off on how long the traces hold up when unsoldering/resoldering.

Whenever I feel blue, I start breathing again.

09-02-2020

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Terry Maddocks
United Kingdom
Posts 5
Joined on 04-04-2017

Post #:	43
Post ID:	25931
Reply to:	9091

Deletion of V2 cathode capacitor and gain

Hi Romy,
I am currently in the process of rebuilding my 834 PT. I see you don't use the capacitor bypass on V2, does this have any effect on overall gain of the corrector? I've recently acquired audio Technica ART7 cartridge which is low (0.12 mv) output and for that, and other reasons, I do not want to lose gain in the rebuild. I'm assuming that there is also some benefit for sound in omitting it?
Cheers
Terry

"Music is enough for a lifetime, but a lifetime is not enough for music" Sergei Rachmaninoff

09-03-2020

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Terry Maddocks
United Kingdom
Posts 5
Joined on 04-04-2017

Post #:	45
Post ID:	25933
Reply to:	25932

834PT and MC cartridges

Hi Rowuk,

Thanks for reply, I use step up transformers, old Partridge 1:12 I think they are model 973B if memory serves me correctly. I haven't installed the ART7 yet. I currently use another AT cartridge - 33ptg ii which is a more "normal" output of circa .3mv... The gain from the combination of Partridge + 834 at present is just right for me, when I switch to the ART 7 I may have to go for a higher ratio.. Maybe 1:20 such as S&B or the Silk models from Sac Thailand.. And of course there are others.. But back to my original question as to whether the removal of V2 cathode bypass capacitor will reduce overall gain of the stage?

Cheers

Terry

"Music is enough for a lifetime, but a lifetime is not enough for music" Sergei Rachmaninoff

	Target	Threads for related reading	Most recent post in related threads	Forum	Replies	Views	Started
»	New	Denon 103: myths and the reality..	A young but mature horowitz...	Analog Playback Forum	29	417935	06-08-2004
»	New	About EAR 834P Modifications..	The cap will not change volume in the pass band...	Analog Playback Forum	45	642330	12-29-2004
»	New	EAR 834P Modification..	The cap will not change volume in the pass band...	Analog Playback Forum	45	642330	01-27-2005
»	New	The last phonocorrector: “End of Life" Phonostage..	Big cap banks...	Analog Playback Forum	310	1989880	11-13-2007
»	New	EAR 834P mods..	The cap will not change volume in the pass band...	Analog Playback Forum	45	642330	11-04-2008
»	New	AMR PH-77: just another phonostage or more?..	Oh, yeah... the sound of the Thing Itself......	Analog Playback Forum	11	133105	07-05-2009
»	New	Denon 103: myths and the reality..	A young but mature horowitz...	Analog Playback Forum	29	417935	06-08-2004
»	New	The tales of two phonostages: Allnic and 834PT...	The tales of two phonostages: Allnic and 834PT....	Analog Playback Forum	0	23511	12-21-2011

	Target	Threads for related reading	Most recent post in related threads	Forum	Replies	Views	Started
»	New	Denon 103: myths and the reality..	A young but mature horowitz...	Analog Playback Forum	29	417935	06-08-2004
»	New	About EAR 834P Modifications..	The cap will not change volume in the pass band...	Analog Playback Forum	45	642330	12-29-2004
»	New	EAR 834P Modification..	The cap will not change volume in the pass band...	Analog Playback Forum	45	642330	01-27-2005
»	New	The last phonocorrector: “End of Life" Phonostage..	Big cap banks...	Analog Playback Forum	310	1989880	11-13-2007
»	New	EAR 834P mods..	The cap will not change volume in the pass band...	Analog Playback Forum	45	642330	11-04-2008
»	New	AMR PH-77: just another phonostage or more?..	Oh, yeah... the sound of the Thing Itself......	Analog Playback Forum	11	133105	07-05-2009
»	New	Denon 103: myths and the reality..	A young but mature horowitz...	Analog Playback Forum	29	417935	06-08-2004
»	New	The tales of two phonostages: Allnic and 834PT...	The tales of two phonostages: Allnic and 834PT....	Analog Playback Forum	0	23511	12-21-2011