If you think a rectifier sounds better than another, then you do not have a technical problem, and small technical problems such as wrong heater voltage are irrelevant.
I don't have a problem at all. I know what I hear. Doesn't everyone?
I don't claim I can hear the difference, but the rectifier choice has an impact on voltage sagging, among other things, which makes a measurable difference to the amplifier's output signal.
A tube PSU is indeed a very complex phenomenon. When you make changes, some of them are clearly audible, some on the threshold of audibility, and some make no audible difference. The question isn't what you hear - that's personal to listeners and nobody else can tell you what you are hearing. The question is why you are hearing it. That's where all the maths, theory and equations come in.
Would you agree that it's fair to say that these pronouncements and posted judgements about the sound of tiny and/or obscure differences should be subject to some verification? A skeptical person would insist on some blinded verification before accepting a stranger's possibly biased writing. For example, I say to you that my cat talks to me, without words of course, but I understand her perfectly. I may believe it, you may believe it, but a skeptical person (like me) may want a better standard of proof.
Audio gives everyone a wide latitude of proof. After all, the important part happens inside our own noggins, so, who's to say I didn't hear it? But that same latitude allows us to be sloppy and not give our judgements the same rigor we would give to financial, political, or interpersonal matters. In audio, it's really pretty harmless, but in the real world, especially in my country, America, respect for the truth is evaporating and a strange anti-intellectual craziness is growing. Maybe that makes me more adamant in demanding rigor in our comparatively calm waters. Dunno.
All good fortune,
Chris
Audio gives everyone a wide latitude of proof. After all, the important part happens inside our own noggins, so, who's to say I didn't hear it? But that same latitude allows us to be sloppy and not give our judgements the same rigor we would give to financial, political, or interpersonal matters. In audio, it's really pretty harmless, but in the real world, especially in my country, America, respect for the truth is evaporating and a strange anti-intellectual craziness is growing. Maybe that makes me more adamant in demanding rigor in our comparatively calm waters. Dunno.
All good fortune,
Chris
1. You can't "verify" small differences in the tonal quality of acoustic instruments. It needs trained ears familiar with acoustic instruments. Orchestral conductors like Boulez etc, for instance, are very good at this, but most conservatoire trained musicians have a good ear for tiny tonal differences. It's their job.
2. You can't tell perfect strangers what they do and don't hear in their own listening room when you are completely unfamiliar with both the person and the listening room and separated by thousands of miles of ocean. You can't hear with somebody else's ears any more than you can see through walls, walk on water or predict the future
3. Telling perfect strangers they have a "problem" and are "hearing things" is insulting and we don't come to this forum to be insulted in this way.
2. You can't tell perfect strangers what they do and don't hear in their own listening room when you are completely unfamiliar with both the person and the listening room and separated by thousands of miles of ocean. You can't hear with somebody else's ears any more than you can see through walls, walk on water or predict the future
3. Telling perfect strangers they have a "problem" and are "hearing things" is insulting and we don't come to this forum to be insulted in this way.
You may bristle, but I didn't say any of the things of which I'm accused.
Been around opera and associated orchestras for many decades. I'm sorry if I've inadvertently offended you.
Chris
Been around opera and associated orchestras for many decades. I'm sorry if I've inadvertently offended you.
Chris
Here you are assuming that he only thinks it sounds better (or different.) It is quite possible that it does sound different. You can not know from where you sit what another person hears.
A far better approach on a forum is to explore why it might sound different and look for technical reasons for the difference. Please remember that your own perception is not global nor universal.
As to one reason why rectifiers may sound different there is interesting post about calculating time constants for power supply - at direct heating triode blog by Fred Mussett, third part about construction of LCR RIAA preamp.
Very nice pictures also.
Very nice pictures also.
While the 5U4 might work fine, using a rectifier with a 2A filament will result in a slightly higher heater voltage that is "in spec". One of the aspects that might contribute to your preference for the 5U4 is that it's directly heated. So maybe consider a directly heated rectifier that only draws 2A of heater current.
The common 5Y3GT might work. It's rated for only 125mA but might be OK since your voltage is lower than the 360v listed on the data sheet. You can use the 3 graphs in the data sheet to check. If it passes all 3 tests, based on your specific application, then you're good to go.
https://tubedata.edebris.com/sheets/093/5/5Y3GT.pdf
Agree.
Some thought provoking question. 🤔
Modelling the same power supplies (cLCRC), one with 5U4GB, other with 5AR4.
The stress test is the same, from 130mA static load (ideal) current jump to 260mA (till 200msec).
The 5AR4 version gives higher output (lower voltage drop at the same current), in this case 24.15V DC more (the 5U4G version gives 234.4V).
Is both PSU behaves the same way (except for the DC discrepancy -let's assume equalization-)?
Is one or the other PSU "sound" different in the same amplifier?
Thanks Bela. I've moved on to another PSU for the input section of the 2a3 amp, which is a 10Y stage. Very interesting results with different combinations, and in this case a SS bridge of 1200V SIC Wolfspeed diodes. I have actually bought the proper transformer for the 5U4 so I'll be replacing the 4.5V transformer. But it was interesting to find out what happens when you run rectifiers under voltage. Thanks guys.