Last edited:
Hi juanitox,
This is a real curio!...your E55L spud amp. Could you please tell more about it and the system in which you use it...sources...loudspeakers...output transformers...design point of the E55L? If you use phono as a source, how do you deal with that?
Thanks and Regards, RC
I can't find any information about them, unfortunately.
I'm sure they're the basic ones, which I guess are level1. They were my first transformers in my 300b amp.. Around 2009. I remember primary being something around 3k. The Hashimoto's were most definitely more expensive.
In SE I have Bud's Level 1, 3.5K. Also his smaller 3.5K ones he made for Wright Sound 2a3 amps, which I prefer. I think they're good transformers, but I haven't heard Hashimoto. I'm mostly using NP Acoustics amorphous 3.5K SEs.
I have two pair H.Purvine IT's and just one pair of his PP OPT.
The IT are single end to push-pull, the OPT are Level 1- 6k6:0,4,8,16
Together, it was (and still is) the best sound I got from an A1 DHT push-pull amplifier.
The IT are single end to push-pull, the OPT are Level 1- 6k6:0,4,8,16
Together, it was (and still is) the best sound I got from an A1 DHT push-pull amplifier.
Last edited:
A have to say Bud is one a few "master coil winders" left in the world. His mid class and upper class transformers are excellent, but as with most things you need to pay up to get the best, his inexpensive xfrms are just ok, like electraprint or lundahl.
I've played around with SE300b for over 40 yrs and here what I've learned. The 300b sounds best with a 4k to 4.5K load and 4.35k seems to be the magic spot. 16 ohm speakers. The grid of the 300b likes to be driven, either with a IT or low imp. tube. One of the best I've found is the 6BX7, look at it's specs, you'll understand why. I don't like pentodes in triode mode. There is something to be said about another DHT, IT coupled driving the 300b grid. If IT then again the best you can afford, properly designed with amorphous or cobalt lams. If cap coupled no aluminum foil, silver or copper foil only.
As for tubes only real WE, European or Soviet. If you ever get to hear a real WE 300b you'll understand why. Never found an Asian tune that comes close.
I've played around with SE300b for over 40 yrs and here what I've learned. The 300b sounds best with a 4k to 4.5K load and 4.35k seems to be the magic spot. 16 ohm speakers. The grid of the 300b likes to be driven, either with a IT or low imp. tube. One of the best I've found is the 6BX7, look at it's specs, you'll understand why. I don't like pentodes in triode mode. There is something to be said about another DHT, IT coupled driving the 300b grid. If IT then again the best you can afford, properly designed with amorphous or cobalt lams. If cap coupled no aluminum foil, silver or copper foil only.
As for tubes only real WE, European or Soviet. If you ever get to hear a real WE 300b you'll understand why. Never found an Asian tune that comes close.
Yes, I'd agree. I prefer 5K to 3.5K. I don't like pentodes in triode either, except for DHTs like 2P29L and 4P1L. I cap couple with FT-2 teflon caps. I find teflon is the best. The 300b can sound a bit warm and euphonic, and all these things keep it more focussed. I still prefer the 2a3, though.
I agree, a true single plate 2A3 is magical. The FT2 is ok, but I've found any cap with aluminum foil adds a bit of harshness. I really love Silver foil w/ teflon...copper foil is a close second. I like paper/oil caps if bypassed with silver. But we we were talking transformers and I got a bit off track. The James are ok and the Hashimoto are decent. A LONG time ago a got a Sowter, pretty good, but no longer made. Bottom line is you need to pay up to get a decent transformer.
I had the good fortune of working for a areospace company for 30 years. I was the Senior Ops Engineer for the coil winding department and we had a CNC controlled coil winder, which when properly programmed could wind capacitors. I wound my own. I got Silver foil from Thomas and Skinner.
Looks like a mid-range* transformer. Is level 1 the entrance level and level 5 "high end"?
* 0.35dB loss I calculated
* 0.35dB loss I calculated
Last edited:
Oh, i forgot to say, did you checked the transformer? Frequency response? I was missing that in the datasheet.
Data doesn’t spec a drive impedance so naturally the freq response will also not be shown.
However, it does spec Lpri for a range of frequencies and signal amplitudes so the LF can be calculated wrt drive impedance and measurements confirm the inductance spec is accurate.
Wrt the HF, 20kHz no problem but as always there are things that unloaded (tube grid to signal common) secondaries show as ‘not so pretty’ despite it ‘sounding preferable’ (to me) compared with a resistor load which will quieten the squirrels. So it will be application dependant.
There are also phase balance issues wrt each half of the secondary, yet somehow it sounds overall ‘more whole’ or ‘complete’ than the tube based inverter/splitters that I’ve tried.