Melvin Leibowitz EL84 HiFi?

[Zarrir]

Hi Valvefreaks. I was looking at the bellow Melvin Leibowitz 1961 design. So simple, 6watt per channel. My question is, can this be considered HIFI based on the current standards?

[shooter]

Cork sniffing HIFI, probably not by todays standards, but to play normal ppl music, should do fine.
for my "HiFi"  I used a 6sn7 driver, UL taped OT, but I used QuadSE 84's and SS rectifier, still wouldn't pass the cork sniff test though, but she rocked a pair of audio Nirvanas quite well!

[PRR]

This was cheap "fidelity" even in 1961. Poor push-pull. NO speaker damping.

May be a fun project. May "bring out" (or add) things you never heard in your records. But far from a transparent playback amplifier.

Nicely drawn, though.

[Ugly Distortion]

http://www.r-type.org/articles/art-003h.htm

I know they were selling tubes, but still I doubt Mullard would have gone through all this effort way back when if it didn't matter, and they also demanded quality iron which they didn't sell.

Resolution is like a drug, you can't enough.

[jjasilli]

My understanding is as follows. Until about 1962, OT's didn't have the full audio spectrum of frequency response.  They had about 100Hz -to- 8K or 10K Hz, out of 20Hz to 20K Hz. However, that limited range is fine for most human voice and mid-range instruments.


Another factor is THD = Total Harmonic Distortion.  This is a bit misleading as it includes all noise and harmonic additions not present in the pure signal input to the amp.  About 2% THD is considered acceptable with 5% borderline unacceptable.  SS amps have no OT to limit frequency response; none of the hiss & noise which tubes tend to have at least some of; and can have THD at tiny fractions of 1%.  Despite the textbook specs, many people prefer the sound of tube amps, even though SS amps score better technically.


Some hi-end tube hi-fi amps like the Harman-Kardon Citation II do have very low THD.  But they are said to sound sterile to some ears.