Marantz 67 se

the tweaker's benchmark gets raped by Lampucera

A fiend brought to me the MArantz 67 which was already tweaked to death. All caps that you can find there are aftermarket goodies. Even tve clock with dedicated power supply is already there.
But they did not IMPROVE the circuit, just changed 1:1 the same parts for more costly ones.
The outputr stage is oryginal - Marantz TOP OF THE LINE HDAM to be found in all top players all the way to 8 000 Eu.
What is HDAM I really dont know. it is something MYSTERIOUS that is so cool they had to hide it inside shiny cans.
They hide it - I open - sez I.

HDAM outpud circuit in a can

tadadadadadadadadadada    drums rolling ...........
open kimono time !!!!

So the HDAM is an amplification stage consisting of 8 discrete transistors and 11 resistors and 4 diodes.
Very nice of Marantz to use discrete components not op-amps, hats off to them, but calling it a revolutionary proprietary high definition stage - is a BIT OF OVERSTATEMENT. Too much marketing BS for my taste. Such output stage was an order of the day back in the times before opamps. Every kid in 1970 could do a stage like this on their first semester of electronics. So I do not consider it such a big deal.
Ken Ishivata "invented " transistors in the same way I "invented " tubes.

I should patent SNIPIT and cover NOTHING - (air) - in the golden can and call it Higfh Transparency Output Stage - HTOS.

I lampized the Marantz first using one triode as an amplifier. It is 6H6P with a 10K anode resistor and 300 Ohms cathode resistor without capacitor bypass.

I managed to convince the owner to add lampucera board inside - we took the digital signal from under the digi-out jack and run a wire to under the Lampucera's input RCA digital socket. The power I stole from a 12 V rail and run it through a 7805 regulator.

New outputs independent of old INTACT circuit for comparison.

This mechanism is a simple but good'un, we replaced it with a 15 Euro replacement from the shop. It is that cheap and easy to substitute.

Ze Sound

Now as good as the Marantz was, as good as the tweaked Marantz was, and as good as the lampized unit was, the Lampucera shows another level. It is in another league. Now this is closer to Marantz 12S  if not better.  That is a very succesful implant.