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Output transformers ? sound quality ?

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#7
Transformer design still seems to be a bit of an art. Some Sowters are excellent, some less so. People generally consider Hammond to be, how shall we say, economy? Yet I thought the measured performance of one of their 1608 transformers was excellent.
 
#9
EC8010 said:
Transformer design still seems to be a bit of an art. Some Sowters are excellent, some less so. People generally consider Hammond to be, how shall we say, economy? Yet I thought the measured performance of one of their 1608 transformers was excellent.
Click to expand...

I've got a Hammond 1620. While perfectly serviceable, I've recently discovered it does not seem to compare to a Dynaco Z565. I'm still in the testing stage, hopeful that perhaps I have a correctable flaw in the design or a faulty tube.

On the positive side, the Hammond cost me less than half the price of a Z565. For the most part, the Hammond sounds just fine.
 
#10
Plitron offers fancy high end toroidal PP iron to 400 watts. PAT-4146-00 may be close to what your looking for. Not cheap.

PAT 4146-00 Application: EL34 150 W
This 150 Watt high power Push Pull output transformer,with a primary impedance of 2.2 kOhms and a secondary impedance of 8 Ohms with center tap (cathode feedback) and with 43 % Utra Linear taps, is intended for six EL34 or KT66 or 6L6 tubes at moderately high voltages (between 350 and 450 Volts). The -3dB (1 watt) bandwidth is from 0.6Hz to 118 kHz while the -3dB power bandwidth starts at 15 Hz, allowing this transformer to be used in applications where full and strong bass response is essential.

http://www.plitron.com/shopping/specs/414600.pdf

PAT 4147 might work if you dont need UL, is much cheaper.
 
#11
Heyboer! Alden always gives me exactly what I want, and I talk to him person to person. I've never been disapointed. You get custom made trannies for only $20 more.

I used Hammond for a few years, but they seem to have a problem with consistency. I purchased a couple of 1650N's not to long ago and I was not happy with the bottom end. It turns out they had the -3 db roll off point well above the 30 Hz they claimed it had. (30Hz-30KHz +/- 1 db). Defective? Maybe a bad batch? Perhaps.

I learned one lesson: Never cut the wires until your completely sure your happy with them, because you'll never get a refund if you do.

I haven't tried Edcor yet but I've heard very good things about them.

~~~John~~~
 
#13
Always read the claims regarding bandwidth (especially bass) carefully. Source Z needs to be specified to fully evaluate the claims. Said claims also need to give whether that its at -1dB or -3dB power or 1 watt etc.

I do not see where Hammond specifies source Z for the claimed bandwidth, it should meet its claim with tubes of sufficiently low Z out. Or it could be they had a flaw etc.

The Plitron pdfs specify a lot, including the tube plate resistance needed to achieve the claimed performance.
 
#14
Danbury tranformers have one model which is very cheap and surprisingly good - 6.6K I've used them several times from EL34 types to 2a3s Mids and treble are really very good - bass a bit lighter than Hammonds, but acceptable.

#Danbury Electronics. Tel: (01245) 328174. Fax: (01245) 328963. ...
http://www.danburyelectronics.co.uk/
20 Cutlers Rd, Saltcoats Industrial Estate
South Woodham Ferrers
Chelmsford CM3 5XJ - David (Dave) Brooks
http://www.livinginthepast.demon.co.uk/xformer.html
http://www.livinginthepast.demon.co.uk/valveaudio.html Mike Holmes
http://www.mc-h.demon.co.uk/xfrmrse.html danbury transformers

Model is😀anbury Code VT1041
 
#15
http://www.livinginthepast.demon.co.uk/xformer.html

Apologies for he above - the smaller 6.6k transformer is the VT425 Price £31.83

this has excellent mids and treble.

The larger VT1041 has better bass but in my view at the expense of those nice mids and treble. It's very gutsy and dynamic, though. I personally like the VT425 a lot, and the frequency response tests very well with no peaks and extended treble.
 
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