Step Up Transformers

[bob orbell]

Hi all, I am thinking of trying some expensive SUT with the aim of removing some annoying sibilance, I know that John Caswell uses Sowter transformers in his phono, perhaps you would like to comment John, I have just been reading about Ortofon's top model, at £1200.00, don't think that I will spend that much, but is interesting to find out if they sound better than the WD model's, any comments?. BOB

[John Caswell]

Hi Bob,
Don't just try new SUT to try to get rid of sibilance as it may be that the SUT requires a Zobel network to calm it or the following phono stage has a HF rise.
Are you able to look at the frequency response thru an inverse RIAA network and a square wave. Very revealing!!
I use the Sowter 8055 SUT due to legacy use when I was in Broadcast. You want the best result, you fit the best components simple as that.
The only measurable difference I could find between the WD SUT and the Sowter SUT was a slightly improved LF response, mainly due I think to a larger core on the Sowter. Frankly I could not hear any difference, and the WD SUT is very very good indeed and does have the advantage of 10:1 or 20:1 step up or 10:1 centre tapped primary. The Sowter 8055 relies on accurate capacitive balance for the primary (which i find to be very good) but does have a centre tapped secondary for balanced amplifier use.

John

[bob orbell]

Thank's for the reply John, no I don't have a scope. or inverse RIAA, I have read about this in MJ's book, I may know someone who can help me, I will make enquiry's and post latter. BOB

[BadBass]

Originally Posted by bob orbell

I have just been reading about Ortofon's top model, at £1200.00, don't think that I will spend that much

How much do you plan on spending?

[bob orbell]

About £4-5000.

[FreddieJ]

Originally Posted by bob orbell

About £4-5000.

Man, that's a lot!

[bob orbell]

Another SUT goes open circuit, I ordered a few bits from Matthew yesterday and told him about the problem with the SUT's, he tells me that he is now using SUT's from another suppler, they are square as opposed to the one's from Peter, dose any one have any comments on these later transformers with regard to sound?, I have also considered the MC1 from Rothwell Audio, any comments. BOB

[Dave the bass]

Ooooerrr, I've never had one go OC TBH Bob. Is the secondary going open per chance? Grid leak from the 1st amplification stage popping it open? That'd be my guess.

[bob orbell]

Hi Dave, this problem has happened quite a few time's with mine and other members, it only happen's to the cylindrical 1-10 / 1-20 SUT, the problem is corrosion of a joint on the sec. there is a picture on here, somewhere , I have fixed quite a few, but am thinking of different one's now, it is not a fault of the phono stage. BOB

[Dave the bass]

Aaaahhh, I see what you mean Bob. I was thinking of ways a Phono stage could pop open a SUT.