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I started this thread on November 22 last year, or about 6 month ago. 3 years back I went for single stage amps and 6 month ago I begin to conceptualize a move for a higher gain for MF and consequentially the DHT in output stage. Today the new MF channel for Melquiades is complete; the amp is finally closed up.  There was an interesting mystery there. I put a large grid stopper - 1K and that made very unexpected change – the gain went up for 2-3dB and frequency response got extended up. I measured is a few times. The crossover point is there and not changed with or without the grid stopper. The minus 3dB I get at 33kHz without grid stopper and at 63kHz with grid stopper. I have no explanation as I increased the grid impedance and the filter against Miller shall be faster. Anyhow, I do not complain as you understand…

Anyhow, the DHT channel is powered now with own dedicated filament transformer and I actually was able with it to get noise even lover – to 0,2mV. There is absolutely nothing coming from MF channel. Still, I took high a sensitivity woofer and the very-very minor 60Hz hum was there. So, all fear of people who have problems with AC on filaments and consequential modulations are warranted, thankfully it does not affect me and I stay with AC.

I am sure that for a next few weeks I will be talking about the “new” sound from Macondo/Milq and the searched 2dB of MF did changed a lot. I need some time to play with different configurations but as what I see now suggests that the project exceeded all my expectations – it truly sounds very-very nice.

I just played the Verdi’s Requiem with a killer cast of Ludwig, Ghiaurov, Schwarzkopf, Janet Baker, Gedda lead by Carlo Giulini. That was exactly what a doctor ordered. I have million thoughts about the change sound but I will withhold conclusions until I will be in the full control of what Milq/Macondo. So, far it is exceptionally good.

I have to note that despite that the double-stage DH MF channels look like does better in context of Macondo but it does NOT answer the question that I raised in the title of this thread: “Single-stage Melquiades vs. DHT amps”. My direct–coupled DHT is not just most stages but it is a different amp. The double-stager has much more idling output stage, it has completely different output transformer with different core, it has essentially only polypropylene and foil in PS, it has different crossover coil with different core and twice higher Q, it has exposure to different flavor of output tubes. So, I would let settle my excitement but who know what I would say if I was able to get from my single stage a few more dB and at the same time to load it twice lighter.

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