GoodSoundClub - Romy the Cat's Audio Site

In the Forum: Melquiades Amplifier
In the Thread: Planning my DSET

Post Subject: Two things I really liked...Posted by anthony on: 8/13/2015

Romy the Cat wrote:
anthony wrote:
I am not sure how large to make the filter caps for the DHT channel. At this stage I think I will start at 3000uF and perhaps try altering it a little up or down once the system is stable.

Hm, it is depends how stupid you are. The 3000uF is an average level of stupidity. In my amp I went for 36000 I believe that was accessibly stupid. In some amp DIYers make SETs with 8uF that is unsufficiently stupid. It is about how much you wiling your transformers, chokes and the rest PS and filter to be impactful to sound. Some folks make vintage tube rectification, use super-duper components in filtration and use very small last cap of a special type, let say paper in oil… Then the sound of the amp is 50% of the sound of PS. I do not say that it is bad and with proper tweaking all of it you can get fine result. I do not like this approach and I prefer to use large electrolytic to cancel out any sonic PS contribution. In my amp it is not about the contributive sound of passive elements but rather about unadulterated sound of active elements. Use the filtration to drive ripples to let say 1-3mMv and it would be good start.

When I read your text above I instantly realised that the '3000uF' filtering caps that I was talking about were for the two single stage channels and not the DHT channel. In your DSET schematic you use a 8000uF filter cap that shares the load for three first stages and the entire DHT channel, so perhaps a value around there is a better place to start. Driving the ripples as you suggest is what I will do. For a power supply that is driving the DHT channel alone, would you stick with one large filter cap or would you go for multiples of say 1000uF?

Romy the Cat wrote:

anthony wrote:
On another point, I got to Sydney a couple of weeks ago and listened to Tax's 'Koshka' Melquiades running a heavily modified AG horn system. I did enjoy my visit and am now quite confident that the Melquiades will suit my objectives. Of course this is a few hours listening in a new room but I heard a lot of things that I like.

It is nice to hear BUT: if you heard the Tax's installation then how you concluded that sound you heard was result of “good Melquiades” but not the result of Tax’s heavily modified AG horn system? What I am asking is how you in the sound that you heard you were able to attribute what you liked to the amps but not to numerous other aspects?

Although Tax has tuned his system to his tastes which are close but do not _exactly_ align with mine the system was capable of playing many genres of music which tells me that it was not a one-trick-pony tuned for a particular 'sound'. This system-wide determination reflects on the amplifiers as well, because I have heard several SET amps that blatantly impart their signature on the music from all genres particularly when used on lower sensitivity speakers (which Taxes are not). I don't want to hear the same sounds in all my music and I did not get that from Tax's system even though there were a couple of 'tunings' that I would like to do to align it properly with my tastes.

My biggest take home from the visit was the systems ability to swing in a balanced and cohesive way. The night before I had been to see Bruckners Eighth at the Sydney Opera House and as you are well aware this piece has large swings in which it seems as though the entire orchestra must throw caution to the wind and just 'do'. Even in the systems that I have enjoyed there always seems to be a 'compression' with these large swings, and this compression seems to be mostly influenced by the amplifier (and sometimes the source) that is driving the speakers, whatever they may be. With Tax's system the swing from light to dark to light and the way that it handled the transients in general was always composed and balanced and comparatively non-compressed. The fact that these transients were handled so well even with Tax's midrange that is a little 'heavy' or 'dark' for me tells me that the amplifier in use is very capable indeed.

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