Luxman MQ60 clone

This became to be my prestige project. I had tested the 50CA10 tubes in an SE-amp, and managed later to lay my hands on a substantial number of that pretty unobtainable tube, enough for a push-pull amp.
Being lazy, I had no other plan but to copy the Luxman MQ60, though I run into various versions, but I see no problems picking one of the designs (the one with the "best" tubes).

The pictures below show two different chassis. I started out with one made of wooden sides and coppertop, but this one has become the home of a 6L6-PP amp. Instead I got a Hammond aluchassis of approx the same dimensions as the original MQ60.

Transformers are bought, and so are tubes but thtat has been a very special story and I still have to check the tubes and see if they are working or not. I guess matching is even a lesser option ...
About transformers. The mains trainsformer is ordered according to the data of the original Luxman transformer and the output transformers are "off the shelf" from somewhere, propably Germany.





The very first design using EdCore's output transformers and god knows what mains tranny. This was ages ago.

Components stocked already. Guess they are still left.

Here we go again. Mains tranny from, OP-trannies from Analog-Metric in Asia.

Testing the layout.

Backlash. Just installed the heavy stuff but no wiring done. Looks cool in the setting evening Sun.

Serious checking of the sizes of the original chassis compared to a chassis from Hammond.

&Got the standard aluminium chassis from Hammond and have started to find out where parts are to go.

Holes drilled and filed.

Backside or front?!

A little note. I thought the EF86 aka 6267 was trioded.

Another peek at the original

... and the backside.

I will just have the indicator lamp on the front on my version.

The schematic.

Almost there.

&Looking good ....??!! or maybe not so good.

Ouch! Tubes to close.

Before a major fix, added a strengthening bar inside the chassis.

A sub-plate for the tube sockets and no fancy rings.

Using a file I elongated the holes to separate the tubes.

And here we go again. Sockets in place

Seen from the underside. Hope the chassis dont fall of the balcony railing.

Transformers in place and revealing a sling problem. The bell ends for the choke is shoring the connections. I can bend the solder tabs a bit but wonder if I will have den enuff isolated.
Also got different caps for the PSU, but these ones are closer to the original values but I need to drill a few new holes - no big deal.

Will this work?! Not a single solder blob yet but noticed during a dry-run taht the endbells of the OP trannies must be turned the other way and I can definitely rotade the sockets for the 50CA10 180 degrees. Will fix this right now!



MQ-60 Modification


Luxman MQ60

Luxman KMQ60

Tube 50CA10

Tube 50CA10 data