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    That Good Old Rectifier Sound

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    sKiZo

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    Re: That Good Old Rectifier Sound

    Post by sKiZo on Wed Nov 12, 2014 3:30 pm

    mantha3 wrote:I have 2 of the Big Bottle GZ37s and they are excellent.  I have a GZ33 as well.  These have become so scarce I look at tubes like this one we are talking about to run on a usual basis to preserve the Mullard reserve.

    Right now I'm looking at a NOS GZ37 for $120 thinking that sounds reasonable, and kicking myself for not buying two at $90 each when I had the chance.

    Bob Latino wrote:About the only time I can "hear" the difference between rectifiers is when a certain rectifier is pushed to the limit of its ability to provide a steady source of DC to the amp. This means only at real high volume levels. At lower volume levels I can't hear the difference between different rectifiers.

    You just described my listening habits perfectly. I suppose I could try doing some comparisons at what most consider reasonable volume levels with efficient speakers and all that yada yada ... but nope ... not the real me ... I prefer to LET IT ALL HANG OUT!! I've also mentioned from time to time my dbx bass synth and range expander ... I do know that can increase the demands on an amp ... significantly. Turn that stuff off, and it's like something dead crawled into my ears.

    Probably explains the difference I hear in rectifiers. The 5AR4 is borderline at best in my situation, and my impression of sterile sound with the solid state rectifiers may just be that I'm prejudiced against things that don't glow in the dark? I do know MY system has much more muchness using the big bottle GZ37. The WZ68 copper cap is strictly backup here.

    And no ... sag is definitely NOT desirable in a stereo system. You're not looking for effects or distortion as you would with an instrument amp.

    Tube Nube

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    Re: That Good Old Rectifier Sound

    Post by Tube Nube on Wed Nov 12, 2014 5:43 pm

    Can I unburden you of your extra GZ37?

    Also let me say welcome to the new "meat" on the forum-- by "meat", I mean Ham!


    JohnOPhonic

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    Re: That Good Old Rectifier Sound

    Post by JohnOPhonic on Thu Nov 13, 2014 3:08 am

    I was reading through this yesterday and shaking my head.  N3IKQ and Bob are absolutely correct.  If the rectifier is "good" and doing it's job, it is to block half of the AC cycle and allow the other half to conduct and "rectify" the AC into DC.  This has NOTHING to do with the signal path.  This has everything to do with the amount of voltage that will be presented to the plates and biases.  The filter caps and chokes smooth out the ripple, not the rectifier.  The only way it will affect sound is if it's loaded down and therefore the voltage sags more than usual (i.e. Bob mentioned with the possibility of volume cranked way up) or if there is some defect in the tube that might put out some trash that is picked up by the signal path.  If the rectifier is doing it's job properly, one would not be able to detect any difference in sound, no matter what the brand might be.

    JohnOPhonic,

    Electronic Technician,

    73 de KX5JT

    P.S. -- This is what my electronic background tells me. However, I am open to any corrections or discussions or rebuttals. Ancedotal accounts of "my ears tell me" but no electronics or physics to back up the statement will not impress me.


    Last edited by JohnOPhonic on Thu Nov 13, 2014 4:24 am; edited 1 time in total

    frank

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    Re: That Good Old Rectifier Sound

    Post by frank on Thu Nov 13, 2014 3:58 am

    Thank you for chiming in John(?). I'm somewhat of an interloper here, but welcome to the Dynaco Tube Audio forum!

    'Frank


    Last edited by frank on Thu Nov 13, 2014 4:06 am; edited 1 time in total

    JohnOPhonic

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    Re: That Good Old Rectifier Sound

    Post by JohnOPhonic on Thu Nov 13, 2014 4:03 am

    Thank you Frank! Yes it's John. John-O-Phonic being a moniker given unto me by another amateur radio operator during a hi-fi AM QSO (conversation on radio). I am very impressed with Mr. Latino, this forum and I am planning on ordering and building his version of the ST-70 in the upcoming months. I'm a "ham" guy and you know we are cheap. I believe great audio does NOT have to cost thousands and thousands and as someone approaching 50 yrs old in a couple of years, I doubt my own frequency response will allow me to tell the difference between a decent ST-70 and the multi-thousand dollar rigs. Never-the-less, I want great audio because I love MUSIC.

    It's great to be aboard!

    John

    frank

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    Re: That Good Old Rectifier Sound

    Post by frank on Thu Nov 13, 2014 5:04 am

    So, OK I'm going to go off on tangent here. Disregarding what a person hears, or thinks he hears.

    I'm not as learned as most posters on this forum. What I have "learned" is that all of the circuitry, from the source to the output devices(in this case power tubes), only serves to control(or modulate) the current flow from the power supply to the load(speakers). In this line of thinking one is not listening to the music, but is listening to the power supplied to the speakers as modulated by all of the electronics.

    JohnOPhonic

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    Re: That Good Old Rectifier Sound

    Post by JohnOPhonic on Thu Nov 13, 2014 5:28 am

    In the purest sense, you're correct. We are never "listening to the music" unless we are sitting in the concert hall/studio as it's being made. We are listening to reproductions from recordings and equipment or from broadcast transmissions and equipment.

    peterh

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    Re: That Good Old Rectifier Sound

    Post by peterh on Thu Nov 13, 2014 5:47 am

    frank wrote:So, OK I'm going to go off on tangent here. Disregarding what a person hears, or thinks he hears.

    I'm not as learned as most posters on this forum. What I have "learned" is that all of the circuitry, from the source to the output devices(in this case power tubes), only serves to control(or modulate) the current flow from the power supply to the load(speakers). In this line of thinking one is not listening to the music, but is listening to the power supplied to the speakers as modulated by all of the electronics.
    One should make a note that the powersupply is designed to be as clean DC as possible, and have
    very little AC remnants as possible. Any trace of AC makes the listening unpleasant ( hum),
    any changes of DC will make the listening inpression "strange".
    A good powersupply will not be part of the sound experience, a bad one will.

    JohnOPhonic

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    Re: That Good Old Rectifier Sound

    Post by JohnOPhonic on Thu Nov 13, 2014 6:47 am

    Very true peterh!  The rectifier tubes are not part of the "cleanup" process however... the filter choke and capacitors and resistors are!!  So they are more critical to having the ripple smoothed out as far as the B+ (plate voltage) goes.  This voltage ends up being our amplified signal as it is swung positive by one final (push) and negative (pull) by the other.  Any ripple will ride on top of it and appear as 120 hz hum.

    I'm learning all the time.... I know that the heater voltages can be a source of hum too since they are AC in the Dynaco's and can be induced into other parts of the circuit if proper wiring is not followed.

    The powersupply has no effect on frequency response of the signal, so cannot "color" the sound that way. Other than improper voltage, sag, ripple and hum... what other effects can the powersupply in general do to change the sound? These are the only things that come to my mind.

    sailor

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    Re: That Good Old Rectifier Sound

    Post by sailor on Thu Nov 13, 2014 10:33 am

    I have said for years that we audiophiles love our distortion. We perceive it as detail. The fact that rectifier tubes still exist is proof of that. As Bob said at low levels the sound difference between diodes and tubes should be nonexistent but when pushed tubes can't keep up with the power requirements and a sag in the voltage occurs. Fortunately tube sag [distortion] is pleasant to the ear so the rectifier tube is still around. Arguably, one of the best sounding amp. if not the best ever made by Dynaco was the tiny ST-35 and guess what, it used diodes for rectification. I am not knocking rectifier tubes, I still use them in my tube preamp and regulate the voltage from them with old fashioned tube diodes.[I love the glow]. But sag is distortion plain and simple.

    PeterCapo

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    Re: That Good Old Rectifier Sound

    Post by PeterCapo on Thu Nov 13, 2014 1:18 pm

    JohnOPhonic wrote:The powersupply has no effect on frequency response of the signal, so cannot "color" the sound that way. Other than improper voltage, sag, ripple and hum... what other effects can the powersupply in general do to change the sound?
    Hi John,

    One thing is the internal impedance of the power supply that varies with frequency.  The power supply has to respond to the demands the audio circuit puts on it (asking it to reproduce audio signals at different frequencies), and if the power supply has a higher impedance at one frequency than another, the sound will be affected.  Yes, the power supply is not in the audio signal path, but, as I believe you noted, the power supply provides the raw material for the amplified audio signal for the amplifier’s output.

    Electrolytics, especially the older ones, have significant equivalent series resistance (ESR) that varies with frequency, and this has been noted as a factor in the warm, rolled-off and maybe even sluggish quality of vintage tube amps (having their original, now very old parts).  There is also consideration of equivalent series inductance (ESL) as well, and there may be additional factors.  I think you’d generally have to look beyond the basic operational characteristics of this kind of power supply and into the particulars of how the components in the supply behave under different conditions.  The following discussion might be of interest: http://www.curcioaudio.com/Audibility_of_PwrSupply.htm

    Back to the original matter of whether different rectifiers actually sound different or not, I mean, this gets to the heart of a long running in-house debate in audiodom.  Do we only accept technical measurements and ignore what we might otherwise hear, or do we disregard the tech side and just hallucinate a lot?  I think a balance can be struck.  The tech side must always be in the picture, though if there is science that might explain the differences in subjective experiences, it either might not really be known by anyone, or, if more in-depth technical information is out there, well, most of us struggle as it is with the more basic things already under discussion.  At the same time, there are enough reports from different people in different places hearing differences in rectifiers (and other things) that I would find it difficult to believe that we are suffering from some kind of mass delusion.

    Regards,
    Peter

    deepee99

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    Re: That Good Old Rectifier Sound

    Post by deepee99 on Thu Nov 13, 2014 2:38 pm

    I'm going with mass delusion.
    Ain't it fun, everybody?
    Except back in my hamming days, I was frequently complimented on the quality of the signal from my Precambrian Age all-tube Collins S-Line, whether on CW or phone, from guys using newer, high-dollar Yaesus or Kenwoods, etc. with s/s on the front-end. Circuit design? Tubes vs. transistors? Crystal quality? Antenna? Ground? Luck? What about the Collins signal made it better?
    Guess if we knew the answer to that, there'd be no reason for this discussion board.
    As JohnOPhonic said, we're not listening to music, just electrons. It's time to call all the universe's electrons into the room and demand an explanation for their irregular behaviour.

    PeterCapo

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    Re: That Good Old Rectifier Sound

    Post by PeterCapo on Thu Nov 13, 2014 3:03 pm

    Here's another aspect of power supplies that affects the sound.  There has been a good deal of discussion in forums like this one (and other venues) regarding just the quantity of capacitance alone in the power supply, regardless of other features of the power supply's topology.  As many readers here will recall, the original Stereo 70, for instance, had 90uF worth of energy storage in the B+ supply.  There may be some difference of opinion as to how much to increase the capacitance, but I think many are in agreement that an increase in the energy storage generally improves the sound vs. the original 90uF.

    sKiZo

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    Re: That Good Old Rectifier Sound

    Post by sKiZo on Thu Nov 13, 2014 3:23 pm

    deepee99 wrote:
    As JohnOPhonic said, we're not listening to music, just electrons. It's time to call all the universe's electrons into the room and demand an explanation for their irregular behaviour.

    Technically, it's the end product pressure waves, not the electrons themselves.

    And really, it wasn't the electrons in the first place - it was the musicians themselves, tweaking, plucking, blowing or whatever they do to their instruments while we're not looking.

    Which of course in reality are just the product of their internal musings and skill.

    That leaves all of us inside their brains. Must get pretty crowded in there for some.

    Matters not - what we hear is all in OUR brains. How we interpret what's heard is strictly personal, on an aural and synaptic level. So, whatever it takes to makes ME happy. If personal preconceptions affect that, then so be it.

    PS. More important than bottle vs solid state? Good chiropracty. Just had my neck cracked professionally, and everything's sounding better now. Just wish I could still feel my toes ...  :-]

    deepee99

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    Re: That Good Old Rectifier Sound

    Post by deepee99 on Thu Nov 13, 2014 3:53 pm

    sKiZo wrote:
    deepee99 wrote:
    As JohnOPhonic said, we're not listening to music, just electrons. It's time to call all the universe's electrons into the room and demand an explanation for their irregular behaviour.

    Technically, it's the end product pressure waves, not the electrons themselves.

    And really, it wasn't the electrons in the first place - it was the musicians themselves, tweaking, plucking, blowing or whatever they do to their instruments while we're not looking.

    Which of course in reality are just the product of their internal musings and skill.

    That leaves all of us inside their brains. Must get pretty crowded in there for some.

    Matters not - what we hear is all in OUR brains. How we interpret what's heard is strictly personal, on an aural and synaptic level. So, whatever it takes to makes ME happy. If personal preconceptions affect that, then so be it.

    PS. More important than bottle vs solid state? Good chiropracty. Just had my neck cracked professionally, and everything's sounding better now. Just wish I could still feel my toes ...  :-]
    Skiz, obviously you need more bass if your toes ain't rattling.

    MarcVBelgium

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    That good old rectifier sound

    Post by MarcVBelgium on Thu Nov 13, 2014 4:24 pm

    sKiZo wrote:
    mantha3 wrote:I have 2 of the Big Bottle GZ37s and they are excellent.  I have a GZ33 as well.  These have become so scarce I look at tubes like this one we are talking about to run on a usual basis to preserve the Mullard reserve.

    Right now I'm looking at a NOS GZ37 for $120 thinking that sounds reasonable, and kicking myself for not buying two at $90 each when I had the chance.

    Bob Latino wrote:About the only time I can "hear" the difference between rectifiers is when a certain rectifier is pushed to the limit of its ability to provide a steady source of DC to the amp. This means only at real high volume levels. At lower volume levels I can't hear the difference between different rectifiers.

    You just described my listening habits perfectly. I suppose I could try doing some comparisons at what most consider reasonable volume levels with efficient speakers and all that yada yada ... but nope ... not the real me ... I prefer to LET IT ALL HANG OUT!! I've also mentioned from time to time my dbx bass synth and range expander ... I do know that can increase the demands on an amp ... significantly. Turn that stuff off, and it's like something dead crawled into my ears.

    Probably explains the difference I hear in rectifiers. The 5AR4 is borderline at best in my situation, and my impression of sterile sound with the solid state rectifiers may just be that I'm prejudiced against things that don't glow in the dark? I do know MY system has much more muchness using the big bottle GZ37. The WZ68 copper cap is strictly backup here.

    And no ... sag is definitely NOT desirable in a stereo system. You're not looking for effects or distortion as you would with an instrument amp.

    In some other posts, I noticed some (Skizo....) are familiar with the TAD company..... check this out :

    http://www.tubeampdoctor.com/en/shop_Other_brands_OEM_Tubes_Rectifier/GZ34_5AR4_Mullard_f31_X8E_NOS_NIB_3805

    Although it's way too expensive, I ordered mine today.... to be prepared when Europe bans the use of tubes in audio equipment ...
    (may sound crazy, but it is going to happen.......I'll have to move to the US :-)))

    Marc

    corndog71

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    Re: That Good Old Rectifier Sound

    Post by corndog71 on Thu Nov 13, 2014 5:15 pm

    [quote="MarcVBelgium"][quote="sKiZo"]
    mantha3 wrote:
    ...when Europe bans the use of tubes in audio equipment ...
    (may sound crazy, but it is going to happen...
    Marc

    Wait. What? Why? Surely you jest. jocolor

    sailor

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    Re: That Good Old Rectifier Sound

    Post by sailor on Thu Nov 13, 2014 5:35 pm

    I think, as has been already explained that the number one improvement to tube stereo is the improvement in electrolytic caps.
    Records are a different story. Almost all recordings, even vinyl records, are converted to digital then sent through a mixer board then digitally recorded then digitally compressed and modified to work on a record then turned back into analog and put on a record. By the time we buy the product it probably has been changed from analog to digital 4 or 5 times and sent through a massive number of OP amps. As audiophiles the best we can hope for is a system that makes us happy or at least we can live with.
    By the way, test instruments can't measure the variations in distortion made by the power supply because they usually measure at a set output and frequency. At a set output and frequency you don't get variations in the power supply hence no variations in distortion.
    I have been an audiofool and addicted sense 1972 and have purchased and sold and modified and built enough equipment to open a nice brick and mortar audio store. I have chased that perfect sound and finally came to the conclusion that there is no perfect sound. Just the sound that pleases you and makes you happy. Fact is the old Dynaco equipment has a lot of distortion some measurable some not but David Hafler had an ear for what people wanted to hear. So there are still people who swear by his original product even today. A couple of years ago I modified a SCA35 and put my findings on this board and quit frankly got hammered for daring to modify a Hafler designed product. I can tell you my redesigned driver stage [very small changes] improved the sound, lowered the distortion and made it 10 times more stable but nobody cared. That hurt, but I help people who have DOA tube amplifier kit builds on another board and am considered the resident expert when it comes to getting a new broken kit up and running so I can live with it. A few people on this board no which site I am referring to. Not flaming, just stating fact.
    As I said before [us audiophiles love our distortion, we perceive it as detail ]. No system no matter how expensive will ever produce Beethoven 9th symphony the same way a live orchestra and choir in a concert hall can. Not even close.
    Just my 2 cents, put down the soldering irons and test equipment and enjoy the music.

    peterh

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    Re: That Good Old Rectifier Sound

    Post by peterh on Thu Nov 13, 2014 6:08 pm

    It's a long debate why measurement does not reflect sound quality.
    Maybe one reason is that amp measurement is done on resistive load, when speakers
    is far from resistive and in addition reflects energy back to the amp where negative
    feedback has to react on the reflected signal.

    I had a hope to buy a hp3580A and start measure with resistive load and speaker load(s) and see
    what effect occurs, but this instrument gone away for me :-(
    Known is that some effects IS measurable some are not. ( yet )


    sKiZo

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    Re: That Good Old Rectifier Sound

    Post by sKiZo on Thu Nov 13, 2014 6:34 pm

    MarcVBelgium wrote:Although it's way too expensive, I ordered mine today.... to be prepared when Europe bans the use of tubes in audio equipment ...
    (may sound crazy, but it is going to happen.......I'll have to move to the US :-)))


    Tube detector stealths hovering over your house as we speak ... RUN!!

    $175 each ... at least I wouldn't have to pay VAT ...

    I took a peek at MojoTone (TAD's US supplier) to see if they listed your tube and stumbled across this. Might want to try one of these as a daily driver:



    Bit more reasonable at $23 ...

    JohnOPhonic

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    Re: That Good Old Rectifier Sound

    Post by JohnOPhonic on Thu Nov 13, 2014 10:01 pm

    Thanks for the replies.  This is a fascinating subject.  What I have learned of course is there is more to the "power supply system" that can affect the sound than I realized, in particular the impedance issues that Peter Capo mentioned.  I can wrap my head around that and agree.  

    That said, I'm not convinced that rectifiers, given they are within specs (i.e. within manufacturer tolerances) and not defective, will change the sound.

    MarcVBelgium

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    Re: That Good Old Rectifier Sound

    Post by MarcVBelgium on Fri Nov 14, 2014 2:53 am


    Tube detector stealths hovering over your house as we speak ... RUN!!

    $175 each ... at least I wouldn't have to pay VAT ...

    I took a peek at MojoTone (TAD's US supplier) to see if they listed your tube and stumbled across this. Might want to try one of these as a daily driver:



    Bit more reasonable at $23 ...[/quote]


    It's an addiction :-))), no cure available.......a jammer will keep the stealths away :-)))

    The GZ-34 STR you mention is a far more rational choice.... but who says I'm rational ??? O_O



    sKiZo

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    Re: That Good Old Rectifier Sound

    Post by sKiZo on Tue Nov 18, 2014 5:49 am

    Somebody refresh my memory ... will the 5U4 family work in an ST120? Electronically similar, but the 5U4's are direct heated instead of the indirect heat of a 5AR4 or GZ34 (or GZ37) ... best I can tell, that's internal, and the pin outs are identical?

    Major concern I understand would be "cathode stripping" on the power tubes, as they'll be getting full DC way before they're ready ... indirect heating avoids that by ramping current up slowly. You can get 5U4's on the cheap, but I suppose not a good trade off if you're saving money on a rectifier only to shorten PT life.

    Then again, that could be compensated for by adding a slow start board?

    PS ... I notice the TAD KT88STR's I just got heat up a LOT faster than the KT120's using the Mullard GZ37. I still give them a good five minutes warm up before jamming ... no big rush here.

    peterh

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    Re: That Good Old Rectifier Sound

    Post by peterh on Tue Nov 18, 2014 6:55 am

    sKiZo wrote:Somebody refresh my memory ... will the 5U4 family work in an ST120? Electronically similar, but the 5U4's are direct heated instead of the indirect heat of a 5AR4 or GZ34 (or GZ37) ... best I can tell, that's internal, and the pin outs are identical?

    Major concern I understand would be "cathode stripping" on the power tubes, as they'll be getting full DC way before they're ready ... indirect heating avoids that by ramping current up slowly. You can get 5U4's on the cheap, but I suppose not a good trade off if you're saving money on a rectifier only to shorten PT life.

    Then again, that could be compensated for by adding a slow start board?

    PS ... I notice the TAD KT88STR's I just got heat up a LOT faster than the KT120's using the Mullard GZ37. I still give them a good five minutes warm up before jamming ... no big rush here.

    5U4 does not have larger current capabilities then 5ar4, at least not at 500V. But it has a larger forward drop.

    cathode stripping is a myth at < 1000V B+ Forget about it! What _might_ be a concern is that solid-state
    rectifiers might give the PSU a voltage peak before the tubes start to conduct ( which by the way a 5U4 also
    will give !) . That's the real reason that you might need a delayed B+. But then, suddenly applying B+
    on a fully heated tube might in itself be bad.

    baddog1946

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    Re: That Good Old Rectifier Sound

    Post by baddog1946 on Tue Nov 18, 2014 10:45 am



    "We listen to live music and also at home—to understand the performers’ intentions and to connect

    with their encoded emotions and discover new personal reactions caused by them.

    In the end that’s more important than a lifelike experience. The live event is always tied to a

    particular time and place. As such it is a singular event.

    At home meanwhile we are in charge of the if, when and what. Our motivation and likely also our

    expectations are different. We look for the ‘magic’.

    Hence getting closer to that magic is the prime rationale for any playback chain."

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