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In Reply to: RE: "trade and right of the maker laws" posted by Tre' on December 17, 2024 at 08:30:30
I also remember Tim de Pavaricini (the designer and the man behind EAR) publicly accusing Romy the Cat of stealing his design and Romy laughing in his face. To be fair Romy gave credit to designer and modified the heck of this pre with PTP construction. It wasn't a ripoff board from Alieexpress.
I don't see a problem with a home copy for ones private enjoyment or a picture to show off but a whole thread of a rip off on a popular Audio site looks problematic for a product still sold by the distributors in this country and I'm not sure why Rod allows it.
Edits: 12/17/24Follow Ups:
design about 80-85% of the Phonostage in the Marantz 7? Looks very close, so I wonder if TdP did some barrowing as well?Plus there have been some upgrades and mods I installed in this Clone I bought just as an experimented and has work out well. They are listed in a few forums around the internet. This is for my own personal use and will not be going any further.
Also, there is a very popular preamp that was built in the 90's and its design was straight out of the Linear Technology Applications.
Edits: 12/17/24
The very much non-definitive EAR 834P Modification Guide
by Loesch Thorsten
Hi,
Given that Romy already let the proverbial Cat out of the Bag (pun intended) I think I may have to make good here....
The EAR 834P is a very simple, but rather smartly designed Circuit, implemented by EAR in a rather skinflint fashion. It's performance is pretty good for the outlay asked here in the UK (where the MM input only Version in basic black sells for under $ 600. I would not recommend the version with the build in MC Stepups anymore (I used to for a while as the build in transformers are pretty resonable), but for the difference in price between the two versions you can get VERY MUCH superior Stepups that you only need to wire up. More on that later.
The result of the skinflint implementation is that while it offers rather good performance, it is being held back in performance by a number of "cost accountant" parts as well as some potentially smart features, that to me simply don't quite work as well in reality as they should in theory. Still, given the brutally simple design and implementation the sound this thing makes is a credit to TdP's abilities to design effective, commercial products.
But hell, this is supposed to be the "Modification Guide", not an Ode to TdP. The notes below come from scratch building EAR 834P copies, the odd mod to units owned by others and conversations with fellow modketiers. In general the improvements from the measures suggested below is NOT subtle. Credit for the majority of things in here should go to many and varied people (the list is too long to print and some prefer to be known just "Friends" or "Associates" or "Aquaintances" (you know who you are), errors, omissions, gaffes, spelling mistakes and other such are mine of course, solely mine.
In order for what I write to make sense I'll link in for now a Circuit Diagram of the 834P, it may soon have to disappear due to copyright issues, so download and save it now in case you don't have it.
There seem to have been some recent revisions to the Unit. I know about many a unit without C2 and some have an extra resistor in series with the output, supposedly to kill oscillation with excessively capacitive cables.
Tube rolling and the application of major overkill external tube regulated supplies has been discussed already. I'll not again do that in detail, peruse the archives please for details and many views especially on the tube rolling.
Forever onwards EAR and to the stuff for which you have to be able to use a Soldering Iron.
Step 1:
=======
Replace C1 and C7 with SCR/Angela/Mundorf/Audyn Tinfoil & Polypropylene Cap's NOT with Hovelands (IMHO). The MIT/REL Polystyrene & Tinfoil or their Tinfoil & Polypropylene may be as good or better, I have not extensively tried them. If you don't have the greenbacks for even SCR Tinfoils mentioned above, try Arcotronics KP 1.72, which I quite like.
If your views differ from mine use whatever capacitors sound "right" to you, may they be TCC Visconol, Vitamin Q or Jensen PIO or even Hoveland. It's your Money and your Phonostage.
Remove C5, R6 & R7, then bridge R7 with a piece of high quality wire. If you want to be sure to stop any possible tendency of oscillation in the cathode follower place a 100 Ohm carbon composite 1/4W Resistor in the R7 Position C5 and R6 remain omited. If you wish to retain an ECC83 for V3 change R9 from 68K to 120K. If you plan to change the V3 to a 12AU7/ECC82 or at least 12AT7/ECC81 leave it as is in Value.
If C3 & C4 are already silver mica (they where in some Units I came across) leave them as they are, if not try finding good quality NOS non magnetic Silver Mica Units, 1% tolerance to replace them. If C2 is present, and you find the sound of the unit a little too laid back, perhaps lacking in definition and extension of very high frequencies remove it. I like the sound MUCH better without C2. Again, other folks like other Capacitors, make your own selection, but PLEASE do not put some "selected Wima MKP's" in there or crapola like that.
The RIAA Capacitors are among the most sonically critical in any Phonostage, so don't treat them as afterthought, but as the main thing. No Skimping. The Capacitors MUST have 1% or better (lower) tolerance and ideally better than 0.5% matching between channels. I like silver mica (non magnetic) best, tinfoil & polystyrene second tied with magnetic silver mics units. Normal Aluminum Foil Polystyrenes of extended foil construction are another big step down, the generic styroflex are pretty awfull and polypropylene & aluminum foil completely useless, but that is just my personal view.
Step 2:
=======
Replace C6 with Elna Silmic 100uF/6.3V or if you must Black Gate 100uF/6.3V. The SG Series Sanyo Os-Con's can be used too, but I like neither the tone of the Os-Con or the BG's, they sound a little sharp, etched and aggressive to MY ears. Again, it's your money and unit. Some people liked BG's on the Cathode a lot. Go figure.
Step 3:
=======
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.
Transformers and rectifiers realy belong into a seperate chassis, so C10 and on are off board, I'd recommend per channel a filter chain using 3 pcs each of 510 Ohm Resistors and 3 each of Nippon Chemic Con 47uF/450V Axial Electrolytic Capacitors (Radioshack in the US sells them) or better for that. Of course such an external unit may be added to an original EAR and the HT MAY be split up there too as detailed above if the original supply is stripped out to make room.
To me such a supply sounds much better on pretty much all accounts compared to the original. I have tried both a completely split supply (two transformers and all seperate from there on) and "semi" Dual Mono Supplies that have a common Transformer and rectifier and split up after that.
I have found (not only for the EAR and other phonostages) that if only one main supply exists the arrangement originally used in the EAR is the better one. If you have two complete seperate supplies, bring the two grounds together near the Input, to signal ground and split the PSU Rail as discussed above, taking care to return the negative side of the second added capacitors directly to the same point where the original capacitor is connected.
Step 4:
=======
Place a 1 Ohm 2W Resistor between the LT winding and the Diode Bride D3, ideally replace D3 by individual schottky diodes. This will reduce the LT Voltage. If it is at around 34V already you can leave R16 (33R) alone, otherwise adjust the value until you get 34V across all the heaters together.
As the heaters are in series in the original EAR 834P it is essentiall if you "tuberoll" to make ABSOLUTELY CERTAIN that the used Valves have identical heater ratings. Some special quality Valves have got higher heater current draws and thus should not be used in the EAR.
Step 5:
=======
For the last few bits try changing Resistors, I agree this is seriously now in the margins, but I still find quite material changes in sound with changes in resistors. The ones with largest impact are:
R1
R2
R12
Also the series resistor in the output if fitted has been reported as quite critical.
Also with some notable influence are:
R3
R8
R9
R10
You are likely to even hear small changes from the other remaining resistors, but these will be quite small.
Depending upon the desired "tone" use whatever gives you what you like, Vishay/Caddock for detail, Allan Bradly (need to be temperature cycled in the oven to stabilise their value and then selected afterwards R2 and R12 are value critical) for warm and fuzzy vintage sound or Kiwame for a sound almost as cosily warm but slightly more modern, Rhopoint non inductive precision wirewound for a "neutral" sound, but the Rohpoints sadly don't come in 750k. I guess I myself would use Caddock/Vishay R12 and Rhopoint for the rest.
Step 6:
=======
If you have the MM/MC Version bypass the internal Stepups and the switching, on all versions you may find that higher quality RCA connectors (Cardas would be my take) may improve the sound further.
As MC Stepup I would at this time recommend the Stevens & Billington TX103, depending upon the needs of your cartridge set up for a 1:10 or 1:5 Stepup. The lower stepup ratio is preferable if your pickup has enough output. The S&B TX 103 vs EAR has been discussed here previously, no need to get into more details. You get the raw transformers and wire them up, finished. Mine are still withut case, just raw transformers with wiretails.
I hope this info is of use to someone, I appreciate feedback from those that have done the mods and remember, YMMV, presented here are ideas, part choices and procedures that make sense to me, they may the polar opposite from what you like.
That said, a suitably modded or scratch build EAR 834P plus a pair of Stevens & Billington TX-103's will give tremendous performance for the final bottom line investment and is likely to embarrass some of of the higher cost "spread" that is around in the High End.
Later T
and even this has some mods to it. Power Supply is totally different with a Choke added. My main filter caps are the same with better quality parts but the Caps on the preamp side are different values.I also bought a "MBL 6010D clone" which is not a true clone but very close to the OG preamp. I did some upgrades and mods to it. One of the best sounding preamps I have had in my system. Using better IC than the NE5532's and NE5534's it came with.
Edits: 12/21/24
It supposed to have those NE5532/4 since the original has them and it costs pretty penny. I thought about it too since I have MBL1521a transport and 311E speakers in a closet but I'll just buy one of theirs integrateds to match the look when I visit EU.
Edits: 12/21/24
Versions of the MBL 6010D, one has the NE5532/4 and the later version has the AD797 opamp. That's why I installed better IC's in mine and it made a huge difference in sound quality. It now has a very wide and deep soundstage. I had a Classe CP-50 and it was not this good. My BAT VK-30 and Transcendent Sound Masterpiece 300b preamps are different with over all musicality being with the Masterpiece preamp.I have two systems, one being all Tube from Tuner/ Phono preamp > preamp > power amp. Now I have a really nice Solid State system from Tuner/ Phono preamp all the way to power amp/s with class a/b power amp and Class D monoblocks. I really enjoy both.
Edits: 12/22/24 12/22/24
Those are your words. Once the patent is over then it is not a "rip off".
There are many examples of circuits being revived. With tube power amplifiers, the Williamson circuit and the Mullard circuit come to mind. Those circuits have been used over and over again, once the patents ran out, by many amplifier manufactures. Once the patent ran out there was nothing wrong with that and no one has ever expressed a concern over it.
So I really don't get what you're saying.
I'm not even sure there is anything patentable about the EAR preamp. To be patentable a circuit has to be something "new", something truly different and never done before.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
I very much doubt it. Its very hard to patent any circuit. Are you willing to post the service manual with all Fets clearly marked? Lets say it doesn't have to be the last one (but why not?) but the one before that. How about facilitating a build support and advice for the perfect copy?
.
Have Fun and Enjoy the Music
"Still Working the Problem"
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