When I built the prototype
Simple 45/2A3, I used a pair of chunky PP opts hacked from a Harman Kardon A500 integrated, brought it to the shop (Angela Instruments). Steve hooked it up to his Pro-Ac Response 2s for background music while we worked. At the end of the day, he asked me to write about it for his old website. Since then I've used numerous SE OPTs on this circuit from cheap Hammond to Magnequest, Tango and Tamura. Tonyboy's sample is fitted with Hashimoto. Yes there is a difference in sound but the basic character of the circuit remains.
Through the years this has become my order of priority in building amps (that sound good to my ears):
1. Input/driver tube(s) has to compliment the basic sonic character of the output. I only use Art Deco period octals or 5-pin, big plates = warm midrange!
2. Fine tune the operating points (mainly by ear but I do use a scope to make sure all basic audio engineering parameters are fulfilled).
3. Power supply has to be stable and ripple free - cool running power transformer (over rated in capacity), always tube rectified followed by a choke.
4. Only carbon resistors and paper in oil caps in the signal path.
Tantalum resistors and silver foil caps in the signal path, Black Gates and/or Cerafines as cathode bypass and in the power supply can sound good but can also be over done, not unlike over cooking a fine steak!
From my late 90s Homebrewer article...
"Lately though, I’m realizing that there are Tango and Tamura “signature sounds”, the Tango tending to be leaner and analytical whereas the Tamura is “juicier.” Regardless of core material, both brands produce high quality sound and I would not want to open another debate as to which is better, but my taste tends to favor the Tamura."I remember vividly after mailing the draft (no internet then), Joe Roberts called and coaxed me to spice up the article by mentioning boutique parts quality and add something about Tamura vs. Tango to please other readers. Soon Joel, Nonong and William ditched their nickel core Nature Sound NS70SE and Tango NY15s for Tamura permalloy and amorphous...Come to think of it, do you guys regret?
IMHO, comparing Tamura, Tango or Hashimoto in a well built and good sounding circuit can be a fruitless task...best to just enjoy the music.
That said, a former student gave me a set of the latest top of the line Thomastik violin strings that cost $100. Still not sure if they sound better and easier to play than my favorite $70 Pirazzis...got to go and continue the break in session