Last night I tried out the standard Maplins 6.6K OPT against the enhanced Super
6.6K OPT with thicker stack, now only available from the makers Danbury.
Amplifier is 2C2212b47591 in ultralinear, no global NFB. The stock part was
predictably lighter in bass, and leaner, but it was also clearer and more
detailed. The Super was richer, fuller, with a more bell like tone to the grand
piano and a bigger bass. Bit of a toss-up really - the clarity and detail was
nice on the one hand, and the fuller tone and bass on the other. I'd suggest,
therefore, that the stock part should be used with output valves with a bigger
rounded sound and good bass, and the Super with lighter, more detailed output
valves. Since the 7591s are more inclined to be lean and slightly bass light, I
left the Super in the amps. I later heard them drive some quad ELS 57s and the
sound was nicely balanced - just right tonally.
The stock part might be good with EL34s, or even a cheapo PP 300B amp using -
say - Sovteks. Thorsten Loesch has recommended exactly that in the past. This
would be an interesting starter project and should sound damn good. It would
also be possible to use the Maplins Mains transformer (also a Danbury part -
cost £29.99) in two monobloks. This means £60 a side for the iron - we're in
Chinese territory here! I'm building the stock OPTs into a rebuilt Leak TL12+
with the same front end - 2C2212b4. I thought of using EL86s which should be a
good match for 6.6K. Will report on results. Andy

Details:
Code VT425 'Ultra-linear' type output transformer for the original Maplin 20W
'Millennium' project. This is a Maplin stock item. Use Maplin Order Code DM53H
Price £29.99

Super 20 – 30W Output Transformer Code VT1041 Price £48.68 inc shipping to
UK Push-pull output transformer for use with a pair of EL34, KT66 or KT88
valves for 20 – 30 Watts output. Improved bass response.

Maplin 'Millennium' 20W Mains Transformer Code VT424 Mains transformer for the
original Maplin 20W 'Millennium' project This is a Maplin stock item. Use
Maplin Order Code DM54J

http://www.livinginthepast.demon.co.uk/xformer.html


=== Andy Evans ===
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