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New member: gjm

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tmazz:
Any sonic changes could be a result of the tubes aging as well.

steve:

--- Quote from: gjm on May 30, 2022, 12:34:14 AM ---
--- Quote from: steve on May 25, 2022, 10:31:00 PM ---I hope all is well with you and family. This is an edit, but now I remember, Graham I believe. You lived in England, I sent the B11A via the route you stated, and you later moved to New Zealand as I recall.

I have made a change or two, not sonically, per se but for longevity. There are also a couple of extra features the
public might like to know.

After 10 years it would be interesting to see if any sonic changes occurred over time.

I have replaced the first (input) high voltage electrolytic capacitor, first stage of 5 filter stages, with a Polypropylene capacitor. After many decades, the electrolytic filter capacitor will eventually become leaky as they all do. The poly capacitor will remain in perfect shape for virtually forever. (It does not alter the sonics since 4 following heavy filter stages, including tube regulation.)

Two other interesting items that the public needs to know.

A. A toggle switch near the back power cord reverses the AC line polarity. (It does not affect the pin 1 ground wire).
In one toggle position, the sound will be more relaxed than the other toggle position. The optimum toggle position will depend upon the amp.

B. There is a rotational control in back so as one can compensate for differing amplifier input impedances (Z); say from
20k ohm input to infinite ohmage input of an amplifier. Of course the control is in parallel, never in series.

Good to hear from you and thanks for the review as well G.

cheers

steve

--- End quote ---
Yup - all as above.  :) My B11a has the switch and control on the back as described.
Sonic changes... I'd need to listen more to be sure, but one track I recently listened to sounded a bit 'muddled'. Not sure if that was the recording, though. The only other change that may have occurred (let's face it - audio memory is pretty poor despite what many reviewers would have us believe!) is that reproduction might not be as 'fast' as it was. Not easy to tell, especially when the power amp has changed.
Would you share the cap change details? Future proofing is only ever a good thing.

--- End quote ---

Hi Graham,

As Tom mentioned, tube aging could account for sonic changes. Thanks.

Changing the amp will almost guarantee the musical quality, speed etc of one's system will change.
A question, has the control on back been rotated, maybe by accident? Just a smidgen could cause a
change as well.

I changed the first filter capacitor after the rectifier from an electrolytic to a Solen polypropylene. It does not alter the sound as there are 4 other filtering stages afterwards to isolate. I still have a couple of the first filter capacitors in my parts box, and they are still test remarkably close to new after 20 years.

I also have one in my test phono stage and after nearly 20 years, the leakage current is still as near new. The reasons are the capacitor's repetitive charging current is so low, just a few milliamps (ma.), and the running temp is quite low.

I did add a 6th filtering stage just to make sure no hum with the super high gain audio systems some are using.
It also does not alter the sonics since it is next to the diodes and first filtering stage. Now 5 stages of filtering after it.

When designing, I ran specialized comparison listening tests with the 11A being in the system VS out of the system.
No sonic changes were detected over the years. Dozens of musical selections were used as some recordings are more revealing than others. Some day we might find a tiny error, but for now the 11A is the true world standard pre-amplifier. One can only match perfection no matter the cost.

One note, the interconnect cables (ics) need to be perfect as well, to match with the 11A. Designing them also required rigid specialized listening testing over months and I still test to this day. There had to be a change sometime back as Vampire, who makes all copper plugs and jacks, closed their business. I found a replacement and all is well.

Cheers Graham and hope all is good down under.

steve

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