| johnm |
Hi.
Does anyone out there have access to the datasheets for the 2 transformers (and 1 choke) housed inside the black crackle-finish section of the pre-amp?
I know the following:
Primary = 110V (orange + brown) / 110v (black and green).
Secondaries:
300V - 0V - 300v (yellow / orange / yellow wires)
5V = x2 green wires
3.15V for 12AU7s = two white wires, and a single dark blue wire (goes to A+ on circuit diagram).
6.3V for 12AX7s = two black wires only.
Basically I have gutted the MC-7R and will be building a modern version of a (cut down) Quad 22 into this. I've always liked the sound of the 22 (when tone control circuits bypassed etc) and will be building a version to power my two Quad IIs. Before anyone says anything I realise there are better designs out there, but - for nostalgic reasons, and to perfectly compliment my Quad amps - I want to stick with this design.
I will be sticking to the original Quad 22 design completely, but will not be implementing any of the tone/filter controls or complicated input system or input pods. I have all the parts already. It will also be self-powered.
My question is can I use the Ming Da transformers for this pre-amp? And what choke would I need to give me the 330V @ 4.5mA I need? There is a 5-henry choke inside the Ming da but I don't know any details, and - being a bit 'green' with the more in depth side of valve theory - how to work them out... yet.
I know the 3.15V windings are redundant so I'll just cut those off and slip heatshrink sleeving over the ends. I think I'm Ok with the other windings, thought the HT is 300 - 0 - 300V on the Ming Da, and it's spec'd as being 310 - 0 - 310V on the Quad 22 (derived from the supply in the Quad II).
Any help/advice grately received... except Quad 22 bashing ;)
Many thanks!
- John |
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