6ER5 Tube Question - Wright WPP 100 Phono Stage

yep i have the answer to your question x1000 i knew George and probably owned more GW stuff then anyone on earth including the WPA22 which only 2 were made before he passed as the third was on the workbench when he died...and the reason why he chose the tubes he chose in ALL of his products was because there was probably NO ONE in the world that had more knowledge of tubes and their capabilities then GEORGE WRIGHT....he started in single digits hanging around one the the most knowledgeable TUBE guys in history...there ya have it

 

How about a quote from the Listener Magazine review, May/June 2002 about the 6ER5 tubes..."George Wright says he uses them primarily because they avoid the "degenerative capacitance" (up to 240 pf) that can result in high frequency deficiencies with other, more common high transconductance triodes like the 12AX7" Peter Breuninger closes the review with this... "I think this is one of the best buys in audio, and certainly one of the very best sounding preamps I've heard, at any price.

I talked to George a few times in 2007 when I needed parts and tubes. I asked about the 6ER5. He said he discovered it when he was doing electronic repairs as a teenager. It was used in TVs. One of his relatives (father or uncle) owned a repair shop and George handled the TVs. He said that's where he learned about tubes and circuits. He said the 6ER5 phono stage was an experiment that happened many years later, but was rooted in those early days. He wanted to try something novel just to see what could be done. He was happy with the results, but said the shortcoming was noise when using low output MCs. I'm including some of my email exchanges with him below. Since there's scant information on Wright products, it would be good for it to be documented somewhere.

For what it's worth, George said his personal favorite among his phono stages was the WPP100c, but he couldn't justify producing it any more because there weren't enough good tubes to keep it alive. He said it wasn't fair to existing owners to saturate the market. That sort of thoughtfulness seemed to be a core value of George.

Mark

From: Mark Ingles
Sent: Tuesday, June 26, 2007 12:59 PM
To: george@wright-sound.com
Subject: WPP100c compared to WPP200c

Dear George,

How much quieter is the 200c is compared to the 100c? Is it significant or subtle?

On Jun 26, 2007, at 9:31 PM, George Wright wrote:

Dear Mark,
The design of the 200C was to improve on what the 100C could do using tubes that are available as new manufacture. It took several years to get it Wright but the 200C is a lot quieter over the 100C and will work down to much lower output MC cartridges.
Best,
George

From: Mark Ingles
Sent: Friday, July 06, 2007 7:37 PM
To: George Wright
Subject: Re: WPP100c problems

Hi George,

Are there any components in the WPP100c that you've experimented with? Better capacitors, for example. I'm curious if anything can be done to improve on its already great design.

All the best,
Mark

On Jul 6, 2007, at 9:50 PM, George Wright wrote:

Dear Mark,
As to WPP100c and 200c, I found that upgrade caps can make the preamp less open and slow down the speed. I used Panasonic timing poly caps in the RIAA section because they are fast and accurate, others did not work as well so I have to say unless you like a lot of soldering the better caps are a bust in these units.
Best,
George

From: Mark Ingles
Sent: Saturday, July 07, 2007
To: George Wright
Subject: Re: WPP100c problems

Hi George,

I'm impressed with your point-to-point wiring. It's incredibly neat and tidy. How do you solder such tiny pieces so close together in such a cramped space?!? God only knows! Maybe you do most of the work outside of the chassis and then place it in during assembly.

I don't want to bother you, but if you're open to questions, I'd love to understand the circuit better. I see a four 10 uF and two 22 uF Xicon's and four small 330 uF electrolytics. What are they doing? There's a resistor directly in the signal path leading to the RCA output jacks. I think it's 604 ohms. Any information you're willing to share would be most appreciated!

Best regards,
Mark

On Jul 7, 2007, at 9:53 AM, George Wright wrote:

Dear Mark,
The 10uf are B+ decoupling for the plates of the 6ER5's and the 330uf are cathode decoupling. The resistors in the path of the RCA output jacks are there for isolation so if the outputs get shorted the 5963's will not get damaged. They are 604 ohm as the black in this case is a multiplier and not a zero and they are 1%. The small reddish resistors are German but I can not remember the brand, they bleed off the 1uf coupling cap if there is no load on the output so the caps do not build up a charge.
Back to the electrolytics, I have tried many types and brands and I haven't seen much change in performance, in my design I tried to off set there effects in the 100C, by using small bypass caps for better high frequency decoupling. .22 uf for the 10's and 22's and .1's for the 330's. As to the construction and soldering, I have taught these techniques to others in these fields and yes I can assemble small components in tight spaces and I have trained assemblers to do the same. Before I opened Wright Sound for vacuum tube equipment, I made customized solid state equipment for radio stations, recording studios and of course myself. I learned over many years how to assemble and build miniature electronics equipment.
I have very good eyes for close up work, were I would work other technicians would bring me a small diode or transistor because I could read the writing without a magnifier. As I age my eye sight is not as good but still better than most, it's my gifting and yes God does know!
Best,
George

My impression, from speaking with him, was that this was his preferred, smoother tube but that it was becoming difficult to find enough NOS. I left with the impression that his is the primary reason why he came up with the WPP200 which uses 5963/12Au7 tubes in their place.

My impression, having owned both, was that the 100 was indeed slightly quieter/smoother and that the 200 sounded more lively/dynamic but it wasn't a big difference and in the end, I retain the 200. More select tubes might have tipped the balance either way.

Perhaps, interestingly, George may not have been a brand/variant type of tube guy in that I had asked him what NOS of 2A3 tubes did he find worked best in his famous 3.5 monoblocks. (Why not "cut to the chase" and ask the creator, right?) He replied that he found the stock Sovtek 2A3's to serve just fine, to my considerable surprise, and didn't havea recommendation. (The early RCA's excel, I think.)

I'm left thinking he was more of a circuit thinker than a tube picker
having left us with some of the most true, point-to-point, simple/pure "valve" amplifiers and pre's I've ever heard...period.