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First of all: I have moved this thread into the Milq Forum…..

RonyWeissman wrote:

I'm going to try and build a Melquiades type amplifier (with some help from friends) following the advice given above  to make it as simple as possible.  I could spend more money for "different" transformer, but I will ask you for advice on that later if you don't mind.

Actually it is quite complicated as I do not think that I rave reasons to advise anything. I did not try a lot of different transformers with Milq and my chose of Lundahl was very targeted: I researched a lot and consulted with many people that I thought were serious, however that chose was not based upon my own experience.  So, the positive result that I got with Lundahls was in a way accidental, still it was positive. I would love to have different transformers bought of custom built and try it with Milq to learn hot is sound would change and I would probably do it if I was interested to become audio builder. Since I have not needs to go into this direction a stopped with Lundahl as it did very well, really-really well.

Still, I would to point out some moments that I have managed to learn. I would like to do it earlier as you, or perhaps others, should have all cards on the tables.

Since you damp the grid of the driver stage with the gas tube the Milq begin to sound very soft and very “elastic”. You could make an experiment by applying -3.4V of a fixed bias directly from filter of negative supply and the Melquiades will sound like a solid stage amp. The gas tube buffer will change the Milq sound very dramatically with this driver but at the same time it will make the amp quite melancholic sort of speak… So, you might need a very “fast” transformer with very high core acceleration rate in order to be able to “publish” all that multifaceted glory of Milq’s driver stage outside of the amplifier. The use of amorphous cores or any other fast cores of your choose is highly advisable.  From my point of view the Lundahl’s amorphous transformers were an excellent chose. They have multiple sections (you do NOT want to use taps) that could be easily rearranged to accommodate any loading you wish. Sonically the Amorphous Lundahls did excellent in full range-Milq.

There are limitations of Lundahls though. They have fix core mass and therefore you can not get a lot of current out of them. My first Milq that had a limited task to “compete” with vantage Lamm ML2.0 was running 200V and 200mA. It is OK mode for 6C33C but I would like to see in there a transformer gaped for 300-400mA. You can not get it out of Lundahl as they have “default” core-size and increase currant handling will loose inductance and consequentially bass. Lundahl is Sweden Company and if someone locally would “incentive” them to make custom transformer, for instance LL1627 but at 350mA and 12-13Henry, then it might be VERY interesting. It was the direction that I was considering to go but then I went for DSET concept and I do not care about inductance or currents anymore. I still use Lundahls in Super Milq: upperbass and HF channels.

Still if you wiling to “spend more money for different transformer” then by all means please do so. This is EXACTLY MY INTEREST the others to try Melquiades: to see what else is possible to get out of this amp. Still, I would highly encourage you to stay with very fast cores: amorphous, cobalt or whatever…

I would very highly advise you to talk with Tribute Transformers

http://www.tribute-audio.nl/

They do amorphous cores and with them you can specify any specifications you want. With 200V on plate you will not drive your tube more then 300mA (it will be less actually), so if you get from Tribute their amorphous thing with around 350A and over 10H then it will be fine. Target to get inductance enough to get 19-20Hz at full 60W of plate dissipation. The Tributes are very slightly more pricy then Lundahls. The only problem with Tribute is that I heard that it takes forever to make those transformers. It was why I did not go with them initially as I was not wiling to wait. I do not know if I was right and since I dived into DSETs I would never answer this question. Now it is your turn guys… BTW, the long lead-time that Tributes has is one of the reasons why I write it now and not “later”.  The only concern that I have I would my wondering what kind if initial plate loading to select for my loudspeakers if I have no flexibility to change loading…. (I do not buy the tap idea)

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