Absolutely. I am curious but short on dedication to be a scientist. My point was that in addition to the effects you listed, there are a host of other differences in physical properties (which are rather tedious to measure) such as susceptibility to RFI, internal dynamic resistance, switching noise, mechanical resonance and thermal expansion of electrodes, to name a few, that affect the sum total of electrical performance and may yield noticeable difference. Hence it came as no surprise for me to find rectifiers with very similar B+ to yield noticeably different sonic presentation.
Yes, no doubt that a better understanding of psychoacoustics help. Seems every individual is "wired" a little differently.
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I've done it with a 6Z4 in a headphone amp. I used it as a soft start. It drops 20 odd volts, wastes electric power, and wore out after 2 years of almost 24H/day power on. It was also about $1. Next time it wears out I'll replace it with a wire.
Praise be to wires. And tho' not a single soul here commented on it, my prior comment on power-supply regulation, either absolute or proportionate. These little things called MOSFETS are just such amazing work-horses in the Power Supply department.
IFR610, as an example. 69¢, 200 VDS and 10 VGS.
Trafo → SS FWB + snubbers → 100 µF → 1 Hy → 100 µF → IFR №1 → 100 µF → IFR №2 → 100 µF.
That's become such a standard HV design for me that I just keep everything “in stock” in my parts caddy. I also include a 10 second B+ delay relay, because they're also cheap and easy. Put it at the "end of the chain". Protect the 610's with low value gate-source Zeners. I'm happy with cheap 7 volt units. Got a bag of 100 for like $2 at a swap meet. All tested good, and in-spec no less.
I regularly see better than –90 dB ripple on the output.
And I rarely opt for absolute regulation. Voltage-divider-chain is good enough.
Just saying.
KISS.
GoatGuy
Great, no problem Tony. Just like me, everyone including you is free to choose not to be a scientist, scientists being curious dedicated people working on phenomena science has not been able to explain. Being less experienced than you, I chose a more liberal open minded position to reduce babies being thrown away with the bath water.
it is hard to be "liberal and open minded" when you take people for their words at face value and not go out there and get it yourself....
sorry, you lost me there....i know you meant this one....this is a Scott LK38 amp that had a blown power traffo...
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Are you trying personal attack Tony? I thought you are a moderator.
sorry if it comes to you as such, no it is not directed to you at all..i apologise....
without my
hat, i am just a regular poster...what i wish is for members seek a "deeper meaning" on things and not succumb to a lot of snake oils out there...
PRR, DF96 and a host of others give good advice all for free, listen to them or at least try to understand what they are saying...
Apology accepted, no harm done. I was just confused, perhaps it is just my unrealistic expectation of your wording choice. I concede that you have more experience in tube electronics, but I work with electronics for more than 30 years. I am not that gullible, I hate snake oil and I do value your opinion and those of other members you mentioned.
Bravo… after all these years of posting, I continue to be surprised / amused / chagrined / and yes… stumped by the great advice of others that I just don't get at the first read-through.
Some of the advice takes days of clicking, reading, doing the math, clicking, reading, thinking about and so on.
Thanks all, GoatGuy
bravo indeed....i used to hate the postings of smoking-amp before as it made my head spin.....the deeper my understanding of tubes got, the more i got to like his posts....and of course who would not like that shirtless dude....? tubelab the tube torturer's contributions are well known....
SY's one liners pack a wallop.....i am glad to be learning from the tube gurus...
SY's one liners pack a wallop.....i am glad to be learning from the tube gurus...
Yes, all SSE boards sold since 2010 have had a place for a silicon diode (1N4007 or UF4007) in series with each plate of the 5AR4. This, along with a CL140 in series with the 5AR4's cathode solve the tube failure issue with some of the current production 5AR4's. There were some bad batches coming from Sovtek and JJ in 2008 and 2009 where several users had brand new tubes spark out on first power up, while the next one lived for years. The quality of today's tubes seems to have improved, but there is always the possibility of a bad batch, so I advise the use of the additional parts. The builder is free to install jumpers in their place, or try it both ways and hear the difference for yourself. I have never heard of any differences in over 100 boards sold.
Who, me? I am a scientific minded person, an electrical engineer at Motorola for 41 years, and I have always believed that the rectifier tube should not make much of a difference in a well designed circuit. Yes there are valid reasons why a tube and a pair of silicon diodes will sound different, but two different 5AR4's, both in good condition?.....Well I saw it for my self years ago and reported it back in posts #25 and 28 of this thread. This was an amplifier of my own design and the rectifier was loafing along at less than 100 mA.
More recently I came across a brand new Sovtek 5AR4 that made my amp sound sick. Not, gonna die tomorrow, kinda sick, but I'm tired of listening to this kinda sick. It turned out that even though the tube worked, and the B+ was within a few volts of the other 5AR4's, one plate had a lower voltage drop than the other, so there was some 60 Hz half wave ripple on the DC output. I heard no hum in the speaker, but my Yamahas are pretty rolled off at 60Hz. I think the bad sound was due to IMD products between the audio and the 60 Hz.
it's funny, years ago when cd players made their appearance on the market, I found a difference of sound between philips and sony and people around me said "but no it can not, is digital, there can be no difference! "...
I did not say anything and I continued my road ...
so when Tubelab says he heard a real difference in one of his own amp, I'm happy and so I have no psychological problem.
I did not say anything and I continued my road ...
so when Tubelab says he heard a real difference in one of his own amp, I'm happy and so I have no psychological problem.
I started using diodes in series with my tube rectifiers back about 16 years or more on my Quicksilver mono block amps. Before installing the diodes the rectifiers lasted less than 6 months. 2 amps x 2 5ar4's each amp=4)5ar4's. I put the diodes in 16 years ago and the amps re still running with the 5ar4's I installed back then.
Yes, I have heard differences between different 5ar4's and both had equal voltage on the plates. One of the best sounding 5ar4's I ever had lasted a few days before the showers of sparks upon turn on one day. After that I installed diodes before the plates on my Dynaco stereo 70's and moved on to 5u4's and damper diodes for controlled slow start up. I'm not a believer in these slow B+ modules being sold today under the idea of cathode stripping....wrong output tubes and too low a B+ for me to consider cathode stripping after all there are designs out there take the Allen Organ amps that use diodes instead of rectifier tubes and hey they have run 50 years or more some on the original tubes.
Sorry...I still don't buy the "If the amplifier or line stage was designed correctly you won't hear a difference." Been playing with electronics 40+ years not an engineer just a lover of decent audio within reason. I don't buy the idea that different caps sound different or different resisters sound different or those special interconnects or speaker cables make a difference.
I've seen one and one only instance where I thought I heard a slight difference in coupling caps in an amplifier and I may have been mistaken.
I could NOT reliably hear the difference, yet the customer could. I stated this back in post #28. Even when the customer told me exactly what to listen for, I could not tell a vintage Mullard from a fresh Sovtek in an amp of my own design. I observed this, didn't believe it, and tried different ways to disprove it, but it happened.
These results were quite surprising to me at the time. When he wanted a particular tube and coupling cap, I got those, after all he was paying for the amp build.
I had some "Made in Japan" 5AR4 tubes several years ago. I don't remember whose brand they were, but they were reliable and didn't spark out........ever, but I ran out of those.
Speaker wire.....is speaker wire as long as it is a heavy enough gauge for the current requirements......mine comes from the auto sound department at Walmart.
Interconnects can make a difference if the output impedance of the driving device, especially a turntable, is high. In this case the cable should be short and of a low capacitance.
Decent quality coupling caps should not make a difference, but they can in some amp designs. As long as the DC voltage on both ends doesn't change with applied signal, and the cap sees a high impedance load, the cap just "passes" AC and minor imperfections do not have a large influence. All decent caps should sound the same.
The cap feeding the grid of an output tube can see a varying load impedance as the grid is driven towards zero volts and positive. It can, and often will be forced to change its DC charge as the output tube draws grid current. How a cap reacts in this region will influence it's "sound." This is especially true in a guitar amp operated into the distortion region. Here, sometimes s crummy paper cap from the 1950's does sound "better" to some players.
Most are also quite piezoelectric. Some film caps and most electrolytics will also exhibit a nonlinear capacitance VS voltage curve.
I can not say whether or not I have ever heard a difference between the usual $1 to $2 coupling caps I typically use in my HiFi amps and the $5 to $10 Audiophile caps the I have put in some amps. If there is a difference, I can't hear it. Note that in these amps the coupling cap drives a mosfet follower on the output tube grid so the cap sees a non varying 470K ohm load.
I can hear a difference in a cranked guitar amp where the coupling cap is connected directly to the output tube grid. Some caps sound extremely bright (older white Mallory 150's), while others do not have as much high frequency crud. I can't say what causes this, I simply added a switch to disable the tweeter on my small portable cabinets when cranking guitar through them. I turn the tweeters on for keyboard use, they make the digital piano sound more like a real one.
I think we all went through the "hifidiotlogy" and that we are almost all out. the capacitive effect and the only thing that I respect in my cables, that and the length and the diameter. the contact points are important as well as the good insulation of the RCA terminal block, the rest is high-margin folklore