Transformer Flux Bands

[Chris]

Thanks Richard, will take this into account that 5mm will give no clearance space for isolation washes etc, also is it worth fitting a copper flux band around the outside of the transformer and have it earthed?

Chris

[Richard]

It's not something I'd immediately think of doing Chris as there's a decent space between TXs and the amp isn't known for hum problems. That said, it's another of those things "out there" which might offer an incremental gain and which all add up.

[Chris]

Guess your right Richard, I tend to over think things but I remember the article in the supplement doing this to the pre2 tx's which I have done, there they are sat very close to each other.

Chris

[Richard]

Pre2 might be different in that they're output Txs for signal level and thus sensitive to picking up hum from near-bye mains TXs.
The problem was in being able to conveniently get them far enough away from mains TXs to prevent hum or shielding them.
The mains TX in Kit6550 may not radiating much hum and the OPTXs may not be as sensitive to it as the signal level ones in Pre2. In any case it's an external fit afterwards so give it a go later if you feel there may be mileage in it.

[Greg.]

When I tried to fit some massively bigger Sowter O/P Tx’s to my WAD 2A3PSE it introduced a buzz to the sound. Thinking it was caused by the closer proximity to the mains T/x, I tried the copper band around the core of that Tx. It didn’t make a blind bit of difference. However, Chris, you have raised a question for me. When I fitted the copper band, I did not earth it. I’m rebuilding my 2A3PSE at the moment and I’ve left the copper band on the mains Tx. Does it need to be earthed?

[pre65]

Originally Posted by Greg.

. When I fitted the copper band, I did not earth it. I’m rebuilding my 2A3PSE at the moment and I’ve left the copper band on the mains Tx. Does it need to be earthed?

I'd say yes.(but I have been known to be wrong.)

[bob orbell]

PSE are different to Push Pull, the later has better PSRR than former, I think. Bob

[bob orbell]

Originally Posted by Chris

I will try to use 4 or more fixings, not forcing or drilling out the TX's. Thanks Bob for underlining the fact of not compromising the integrity of the TX's, might be obvious but always worth stating the Do's and Don'ts. I have cork under the TX's now but will try different materials to see if there is any difference in performance.

Will order parts next week, have bought too many bits in the last week, cables, ribbon tweeters.

Rebuilt the pre 2 last week, massive improvement (new thread if interested)

Chris

Well my advice to improve the Pre II is scrap the piece of **** , the Pre III is light years ahead, but why do you need gain ? Matthews new Cathode Follower will also be very good, unity gain here, I had a Pre II years ago along with a KAT 6550 and found the Pre to be weak and very unmusical it also hummed, it was very quickly modified to CF, this was very good, I then moved on to John Broski's Akidio CF, this has proved to be bang on perfect with zero noise, the topology has excellent PSRR, the latest and possibly the last mod is regulated power supply's for my Pre and Phono . Bob

[Chris]

Sorry Bob, that your Pre2 build turned out to be piece of ****, mine is completely the opposite, I have a Ayon cd player that has it's own output so I do not need a pre amp. Below is an extract from a review of the Player.

"Many have failed, as their players have not delivered the finely contoured, velvety sound that comes from a good preamp.
The Ayon, however, is a different story! It has such a clean, well-balanced output that most preamps are not going to help it. Literally, there is a good chance that a preamp will detract from the Ayon's sound. Lately,I have been using three respected preamps at various price points, namely the Cambridge Azur 840E, Jeff Rowland Capri, and VAC Renaissance Signature Preamplifier MkII, and every one of them has to work to recapture what is lost from the Ayon. Shoving the signal through an additional set of interconnects and another component simply is not conducive to the ultimate Redbook performance. Consider that adding preamps vastly increases the cabling and electronics after the source.The VAC preamp is exceptional, and gets one almost back to the point of the Ayon’s pristine signal. It takes some of the best gear available to pass on a signal from the Ayon unmolested. The cleanest and most cost effective solution for the audiophile on a budget is to run it direct into the amp(s)."

However the Wad Pre2 enhances the sound completely of my Ayon player! Bob what you built is a completely different beast to what I am using from how you describe it.

[Richard]

Yes Bob seems to have been unlucky with his but many on here enjoy theirs.

The gain can easily be lowered but you cannot increase gain from a lower-than-unity cathode follower. It may pick up hum from a large nearbye mains TX so position it away from such.

I vaguely remember something about banding the TXs, can anyone point to the article or when it was printed?