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Wojtek wrote:

I assembled SUN 2A3 amp for my friend and found it to be quality kit  and very easy assemble. Kit was old .I think late 90's so maybe quality deteriorated since then. I have variety of 300b Czech tubes and (Eml 300b , KR 300BLX 842VHD ) bought them to build 300b Melquiades but compression drivers buing frenzy is draining all modest resources I have. Lstening to those tubes I have to agree with Adrian assesment . The thing which attracted me to them was AA tube guys opinion that they sound solid state . They expressed the same opinion about6C33C so I fthght that this DHT will fit in the schema of things. Back to topic I found VT52 to be the best sounding tube, harmonically rich, dimmensional with full seductive midrange withouto little histerical qualities of tubes like 45, 6A3 . In Sun kit it sounded considerably better (to me ) with simple DC 6.3V filament than 6A3 and 45 amp .

About the out tubes I have a strong bias to 6.3 as Milq has already a very good a 14A supply for ½ 6C33S and to hook up one more amp for something like 6A3 will be very easy and comfortable. To be persevered I have order a transformer with 6.3 primaries and multiple secondarys:  2.5V, 5V, 7.5V. Still I would like do not have any AC transformers in the Milq chassis. People usually do not like 6A3 and any high voltage DHT time as they are too loud with AC supplies. However, in my case the amp will be DSET, high-passed at 3.2kHz, and I do not think that it will be a problem with noise at all. I did not feel that any modulation would be a problem as well. I might stay with 2.5V if the 2A3 turn out to be better than 6A3, I do not know at this point.

There are 3 basic groups of those tubes as I see them. First one has plate of sub 1000R: 2A3/6A3, AD1 and many others. The second has plate between 1500R and 2000R: 45, VT52 and many others. And the third one has plate above 5K: 10, VT25 and many others. Each groups need own transformer, I have a few for the first gas and none for the last groups. I personally would like to use something like 10Y and with my DSET setting it would not be a problem to wide a high-ratio transformer.  So, if I go for none-2A3 solution then it would be most likely not the second group but the third one. It is possible that the first group will be enough for me, of even that my single-stage high-mu IDHT will do just fine in the end. I will see how the Sun Audio kit will behave with MiniMe and will go from there. The MiniMe shell have a very upper range and if it was the case then it will decide the thing…

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