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    That Good Old Rectifier Sound

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    frank

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    That Good Old Rectifier Sound

    Post by frank on Sun Nov 09, 2014 2:57 am

    I'm not sure if this is a survey or the start of a debate. I guess I'd just like to get other viewpoints.

    A while back I blew up my nice vintage Mullard rectifier. I'm pretty sure it was my fault. It was the only time I powered up my amp with the source volume cranked up, and it was the only time(yet) that I lost a rectifier tube.

    I had previously acquired a Ruby 5AR4 as a backup, so I put it in. Right from the start, I thought the sound was changed. It seemed more electronic-y, more transistor-y. Less warm and inviting, more cold and harsh. After some time, I ordered a "New Mullard" made-in-Russia. I have been using it since. I think the sound is somewhere between the original vintage Mullard and the Ruby. Much better, but not as good as before.

    So, I'm basically asking: Is this all in my mind? does anyone hear a definite difference between various rectifiers? I'm considering spending a boatload of cash in order to get another vintage Mullard, so your experience is appreciated.

    Thanks,
    Frank

    sKiZo

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    Re: That Good Old Rectifier Sound

    Post by sKiZo on Sun Nov 09, 2014 3:26 am

    Let the carnage begin!!  rabbit

    I also find that the rectifier used makes a BIG difference in what you're hearing. Some say, volts is volts, but the best argument I've heard is how the volts are created can have a a major impact on how the rest of the circuitry interacts. Same difference as you'd see changing a grid on a power tube ... electrons are electrons? With a rectifier, the operating characteristics of the tube design can and will change the linearity and response of the output tubes. Power draw and how many amps it takes to create the B+ can also shift the "sweet spot" of a design significantly. I suppose whether this affects what you're hearing depends on your equipment and listening habits.


    Anyway - the Chinese 5AR4's don't sound bad, but don't hold up when compared to a NOS 1950's Mullard 5AR4. I also find the GZ68 copper cap to be harsh/pinched compared to either. None of them hold up to a Mullard GZ37 that's my daily driver.

    Seems to me the biggest difference is that the 5AR4's are borderline capable on an ST120, especially trying to drive a quad of KT120's at 60mV. Right at the edge of browning out with high impact audio. The GZ37 doubles the max pass capacity of a 5AR4, so no worries about hitting the wall.

    I also ran a  Philips 5R4GYS for a bit and found that to be very capable with a quad of KT88's. Couldn't handle the KT120's at the higher bias though. Recently picked up a set of TAD KT88STR's and loving those, so I may try switching the Phillips back in and see what happens.

    Worth repeating ... these results are with an ST120. Any of the big bottles I use would be ... problematic ... on a stock Dynaco without some serious upgrades.

    PS ... haven't tried any of the "new" Mullards yet ... no big rush ... I'll wait till they've had a chance to establish a track record before biting.

    Oh. I never ever run signal to the amp until it's had a few minutes warmup. I've also got mine set up for slow start which helps. It's also the last thing I turn on in the system - otherwise, the HTPC digital server can put a pretty good thump to the speakers when it boots. Best avoided.

    deepee99

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    Re: That Good Old Rectifier Sound

    Post by deepee99 on Sun Nov 09, 2014 1:18 pm

    Skiz, ditto here. Amps are the last to light, after everything else has thumped in.
    I have a pair of antique Mullard GZ-33s that perform beautifully in the M-125s. But they're so spendy nowadays that I only pull them out for visiting royalty, or when the outside air temp gets down to -10F. The Webers work pretty well for my tastes, but there is something a little fatter and sweeter with the Mullards. Plus they look cool.


    sKiZo

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    Re: That Good Old Rectifier Sound

    Post by sKiZo on Sun Nov 09, 2014 8:06 pm

    I run my GZ37 full time here. Gonna find out just how bulletproof they really are.

    Keeping an eye out for a good spare, but right now it's not even breathing hard driving the new TAD KT88STR's ...

    Which btw are sounding better all the time. He shoots ... he scores!! cheers

    PeterCapo

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    Re: That Good Old Rectifier Sound

    Post by PeterCapo on Sun Nov 09, 2014 9:52 pm

    frank wrote:So, I'm basically asking: Is this all in my mind? does anyone hear a definite difference between various rectifiers? I'm considering spending a boatload of cash in order to get another vintage Mullard, so your experience is appreciated.

    Thanks,
    Frank

    No, it is not all in your mind.  Yes, I hear a definite difference between various rectifier tubes.  Instead of spending a boatload of cash on another vintage Mullard, consider the current production Gold Lion GZ34, Tung-Sol and Mullard labeled reissue 5AR4.  You might be able to buy all three for the price (maybe less) of one vintage NOS Mullard, and then you can report back on how they sound.

    Regards,
    Peter

    dougmon

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    Re: That Good Old Rectifier Sound

    Post by dougmon on Sun Nov 09, 2014 10:54 pm

    I'd just like to echo the opinions of many of the people here. I have an NOS Mullard GZ-34 and an old Scott (labeled Scott, probably Matsushita), and they both affect the sound in the VTA ST-70.

    In the near future, I'll be checking out at least the GoldLion GZ34 -- if it sounds good, I'll leave it in, and if it lasts, I'll report back on the sound.

    mark four

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    tube rectifier

    Post by mark four on Mon Nov 10, 2014 6:24 am

    i put some of my  mullard rectifiers  away and started using sovtek gz34's  just because of escalating prices of vintage tubes . you are correct about the three for the price of one vintage tube . if gold lion is better than sovtek i would move these out in a minute . what i read on jj gz34 tube i read didn't give good marks . it would be an interesting topic for discussion  . i am all ears .

    frank

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    Re: That Good Old Rectifier Sound

    Post by frank on Mon Nov 10, 2014 8:37 pm

    Thanks for the responses. I have learned this so far: If I am imagining that different rectifier tubes sound different, I am not alone.

    It looks like the Gold Lion GZ34 is made by New Sensor, as is the new Mullard. It doesn't necessarily mean they are the same tube, but I wonder...

    So far, no one is talking me out of getting an OS Mullard. This is disturbing.

    Jim McShane

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    Re: That Good Old Rectifier Sound

    Post by Jim McShane on Mon Nov 10, 2014 11:00 pm

    It looks like the Gold Lion GZ34 is made by New Sensor, as is the new Mullard. It doesn't necessarily mean they are the same tube, but I wonder...

    First off, let's be clear about something. Just because a tube looks the same externally doesn't mean it is the same tube! What about cathode melt, grid wire material, wire/electrode/element spacing, vacuum level, etc.? You can't see those things, but they are CRITICAL differences in tubes.

    Second, much if not all of a tube rectifier's "sound" is related to the internal impedance of the rectifier.  A rectifier tube with higher internal impedance will have a lower output voltage which will in turn affect the operating points of every circuit it powers. Higher internal impedance = larger voltage drop under load; and the higher the current draw from the rectifier tube is, the more voltage drop will occur. Also the tube's ability to deliver current is a function of the heater voltage as well. There is more cathode activity at 5.3 volts than at 4.7 volts although both those voltages are within normal tolerances for a 5 volt heated rectifier.

    The new trio of rectifiers are all made in the Saratov, Russia plant that is owned by New Sensor, although the plant was making tubes long before NS bought it.

    My experiences with the new Tung-Sol and Genalex branded tubes (I don't carry the "coin" or "wafer" based Mullard reissue GZ34) is that they are really good. I have had zero failures as well, and many of the rectifiers have gone to work in difficult circumstances. I've posted this before on another forum - I do not believe there is any reason to spend big money for the ever dwindling supply of NOS 5AR4/GZ34s. The new T-Sol and Genalex are GOOD!!

    So you don't need to be disturbed any more!

    mazeeff

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    Re: That Good Old Rectifier Sound

    Post by mazeeff on Tue Nov 11, 2014 7:42 am

    In the guitar world, tube sag is a commonly discussed subject. Here is a good article describing it.

    http://www.aikenamps.com/index.php/what-is-sag

    If you believe the article, and its relevance to audio amps, one could conclude that tube rectifiers do indeed have a impact on sound. The article describes "audio compression", as the result of sag. For some guitarists, this is sought after. Just curious how this relates to our world!

    Mike


    Last edited by mazeeff on Tue Nov 11, 2014 10:27 am; edited 1 time in total

    anbitet66

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    Re: That Good Old Rectifier Sound

    Post by anbitet66 on Tue Nov 11, 2014 10:15 am

    Gentlemen,

    As someone with the technical training from 30 years ago, I agree with Jim about everything he said about tubes (and some stuff he mentioned that I never learned about when in high school).  The recitifier will impart little to no "sound" to the amplifier since it should all allow the same current carrying capacity and "sag" when under load for any given type either NOS or new production.  There will be a difference when a recitifier ages and is not as efficient at its job, or if a different type is used instead. bom

    That said, I can imagine there are many reading these words, as well as Jim's and rolling their eyes and saying what a load of BS this is.  I have grown up using tube amplifiers all my life.  I am by no means an audiophile (or 'phool).  I definitely hear a difference between amps of all different types, but I have never heard a rectifier tube cause a major shift in audio quality other than putting an old worn out tube in place of a good one, or using a different type for a specific reason, usually because I don't have the correct one on hand and I'll use what I have.

    If a NOS Mullard, as an example, has a certain voltage drop and current rating and I find a sub $20 tube that matches the Mullards voltage and current specs, my guess is in a double blind test the results of listening would be statistically neutral as to picking which rectifier was installed in the socket at any given time.  But I would bet the Mullard would live a much longer life than the new tube, offsetting the much higher price that they command.

    That's just my 2½ cents worth.  Tony

    zx

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    Re: That Good Old Rectifier Sound

    Post by zx on Tue Nov 11, 2014 11:18 am

    Let me say thanks for all an any input on tube audio.... an from a tecks point of view... a lot may not look like it well sound diff....
    Good point on the ... rolling of eyes....Talk to most... an guys that build an sale $5-50K SSamps...
    Tube heads like to play with our tube sound.....an most in audio to day dont...an to us tube guys... it dose not have to be a BIG diff in sound....how ever i hear a diff in just about all things with the Right speakers...but i gess thats just me...hehe... an in the end thats all that matters...........
    Take a pr of Apogee Stages... Fullrang ribbon speakers i have playing now...ea have a flat Bass size of 4ea 12' drivers....an a mid-tweeter that would be 20ea 1" dome drivers ....thay dont miss much......

    Just one mans o-pine.....Have fun with tubes...



    Thanks for the site Bob...........................

    Dale Stevens

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    Re: That Good Old Rectifier Sound

    Post by Dale Stevens on Tue Nov 11, 2014 6:06 pm

    Tony, I'm new; Define "sag". Dale

    frank

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    Re: That Good Old Rectifier Sound

    Post by frank on Tue Nov 11, 2014 6:47 pm

    Dale Stevens wrote:Tony, I'm new;  Define "sag".   Dale
    "sag" is the drop in voltage which occurs when the current demanded by a circuit exceeds the amount the power supply can provide.

    mantha3

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    Re: That Good Old Rectifier Sound

    Post by mantha3 on Tue Nov 11, 2014 9:48 pm

    I have come close to buying one of these 5R4GYS made in holland....

    http://www.upscaleaudio.com/philips-5r4gys-made-in-holland/

    sKiZo

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    Re: That Good Old Rectifier Sound

    Post by sKiZo on Tue Nov 11, 2014 10:20 pm

    Been there, done that ...



    http://dynacotubeaudio.forumotion.com/t1649-philips-5r4gys-rectifier

    Short version. Looked nice amongst the other big bottles. It worked fine for a short time, then started fading fast. If you look at the meters, they're showing a strong 55mV right after installing it. Bias it up, turn it off, next time it'd be down maybe 5-10mV, and went downhill from there fast.

    Problem being, I bought it and let it sit while working on other stuff, and by the time I found the problem, it was past warranty. Too bad, so sad, was the response. Not sure how many hours I actually got out of it. Minimal.

    Haven't had it out for quite some time, having scored a tasty Mullard GZ37 to replace it. Currently running a quad of TAD KT88STRs, so popped it back in for a test. Topping out at around 30mV with the bias pots cranked all the way up. So ya, it's basically toast.

    Your results may vary.

    PS ... Sag is NOT something I have to be concerned with using the GZ37. That's got capacity to spare, even driving a quad of KT120s ... doesn't even breathe hard.

    Tube Nube

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    Re: That Good Old Rectifier Sound

    Post by Tube Nube on Tue Nov 11, 2014 11:00 pm

    After lighting up, and burning out a cheaper rectifier by turning the amp off and back on right away, I now find all my tubes are lasting years without trouble. With this expectation reasonably in mind, I wouldnt hesitate to spend between $100 and $200 if that's what it takes to get an old stock mullard gz 33, 34 or 37. It seems most reporting here hear a difference that, to me, is worth the cost of exploring it.

    If I prove to be a sucker, or my gear / ears not up to the task of discerning a difference, well, one can be as certain as death and taxes that the Mullard can be flipped!

    wgallupe

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    Re: That Good Old Rectifier Sound

    Post by wgallupe on Tue Nov 11, 2014 11:27 pm

    mantha3 wrote:I have come close to buying one of these 5R4GYS made in holland....

    http://www.upscaleaudio.com/philips-5r4gys-made-in-holland/

    I bought 2 from Upscale before I read about some of the 'concerns' mentioned by skizo. After reading Bob's comments that they should work OK and not harm an ST120 (but may reduce power output a bit), I decided to put one in my ST120. It's been working fine for almost a month now. Been checking bias regularly and it is stable. BTW, my power tubes are KT120s.

    Wayne

    sKiZo

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    Re: That Good Old Rectifier Sound

    Post by sKiZo on Wed Nov 12, 2014 1:46 am

    Keep us posted on long term service. I may have just got a bad one. As stated, mine biased right up out of the box, no problem. Just didna last long.

    The "not our problem" attitude of Upscale was a problem for me though. Yes, it sat for a while between purchase and plugging it in and I missed the warranty period (not by much), and I suppose it'd be hard to prove how many miles were on it. (mutter mutter mumble) ...

    If you have two, I would definitely switch out so both get a decent workout before the warranty expires. Just sayin' ...


    n3ikq

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    Re: That Good Old Rectifier Sound

    Post by n3ikq on Wed Nov 12, 2014 11:39 am

    I'm a newb but I find the conversation interesting. Having never heard the effect of different rectifier tubes, I can only speak from a theoretical point of view. As I see it, the job of the rectifier tube is to provide pulsating DC to the filter capacitor. The filter cap is the "pool" of electrons from which the output tubes draw current. As long as the pool remains sufficiently full of electrons, the tubes are happy. If during a transient like a base drum hit, the cap becomes starved of electrons, the B+ voltage will briefly sag effecting the sound. This can be observed with any cheap solid state amp when the panel lights dim to the music when running hard. Accordingly, B+ voltage sag, which is actually a design flaw, must provide a pleasing effect to some listeners and be partially responsible for the "tube sound". It would seem to me that the size of the filter cap would be the biggest determiner of voltage sag rather then the rectifier tube. I'm sure I'm not saying anything you all don't already know but I'd agree that a blind comparison between tubes would be the only "scientific" way to determine if the difference is really "all in your head" or not.


    Last edited by n3ikq on Wed Nov 12, 2014 12:01 pm; edited 1 time in total

    PeterCapo

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    Re: That Good Old Rectifier Sound

    Post by PeterCapo on Wed Nov 12, 2014 12:00 pm

    5R4GY is rated for 4uF capacitor. We've generally got around ten times that capacitance after the rectifier. Not sure it is surprising if they don't last?

    http://www.tubebooks.org/tubedata/HB-3/Receiving-Type_Industrial_Tubes/5R4GY.PDF

    Bob Latino
    Admin

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    Re: That Good Old Rectifier Sound

    Post by Bob Latino on Wed Nov 12, 2014 12:07 pm

    n3ikq wrote:I'm a newb with no pre conceived bias but I find the conversation interesting. Having never heard the effect of different rectifier tubes, I can only speak from a logical point of view. Very simply, the job of the rectifier tube is to provide pulsating DC to the filter capacitor.  The cap is the "pool" of electrons from which the output tubes draw current. As long as the pool remains sufficiently full of electrons, the tubes are happy. If during a transient like a base drum hit, the cap becomes starved of electrons, the B+ voltage will sag effecting the sound. This can be observed with any lesser solid state amp when the lights dim to the music when running hard. Accordingly, B+ voltage sag, which is actually a design flaw, must provide a pleasing effect to some listeners. It would seen that the size of the filter cap would be the biggest determiner of voltage sag rather then the rectifier tube. It would seem that a blind comparison between tubes would be the only "scientific" way to determine if the difference is really "all in your head" or not.

    I agree with what has been said here .. 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.

    An analogy (which admittedly may not be perfect) is that almost any car battery may be used to start an automobile at normal temperatures but some auto batteries do have more "reserve power" if you try to start your car on a very cold morning.

    Bob

    deepee99

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    Re: That Good Old Rectifier Sound

    Post by deepee99 on Wed Nov 12, 2014 12:16 pm

    n3ikq wrote:I'm a newb with no pre conceived bias but I find the conversation interesting. Having never heard the effect of different rectifier tubes, I can only speak from a logical point of view. Very simply, the job of the rectifier tube is to provide pulsating DC to the filter capacitor.  The cap is the "pool" of electrons from which the output tubes draw current. As long as the pool remains sufficiently full of electrons, the tubes are happy. If during a transient like a base drum hit, the cap becomes starved of electrons, the B+ voltage will sag effecting the sound. This can be observed with any lesser solid state amp when the lights dim to the music when running hard. Accordingly, B+ voltage sag, which is actually a design flaw, must provide a pleasing effect to some listeners. It would seen that the size of the filter cap would be the biggest determiner of voltage sag rather then the rectifier tube. It would seem that a blind comparison between tubes would be the only "scientific" way to determine if the difference is really "all in your head" or not.

    Hello November 3 India Kilo Quebec, welcome to the looney-bin. "Sag" is, methinks, something guitar-players obsess about as being desirable. For this bottle-head, the less the better and with capacitance the more the better. I don't want my amplifiers (or preamps) to be anything other than transparent. Yes, tubes add a certain flavour to the equation, but then, so does solid-state. It's a Ford-Chevy thing. To steal a line from MontanaWay of this board, tube amp design reached its nirvana in the 1950s and can only be improved upon with a few tweaks and the far better components available to-day, especially in the capacitor department. IMHO, s/s designs still have some catching up to the best Hafler and McIntosh tube sounds from back then.
    Here's a thread idea. What are the world's best caps for Hafler/Dynaco designs? We could start a whole nother food-fight.

    dougmon

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    Re: That Good Old Rectifier Sound

    Post by dougmon on Wed Nov 12, 2014 12:29 pm

    So, if I'm understanding correctly what Bob and Jim are saying, the only times different rectifiers make a difference in sound would be due to the wear on the given rectifier. That is, if a rectifier is fifty years old and in the middle or last stages of its life, it _will_ make the amp sound different than a brand new Sovtek. Is this correct?

    mantha3

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    Re: That Good Old Rectifier Sound

    Post by mantha3 on Wed Nov 12, 2014 2:44 pm

    Good to know and I won't make the same mistake.  

    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


    sKiZo wrote:Been there, done that ...



    http://dynacotubeaudio.forumotion.com/t1649-philips-5r4gys-rectifier

    Short version. Looked nice amongst the other big bottles. It worked fine for a short time, then started fading fast. If you look at the meters, they're showing a strong 55mV right after installing it. Bias it up, turn it off, next time it'd be down maybe 5-10mV, and went downhill from there fast.

    Problem being, I bought it and let it sit while working on other stuff, and by the time I found the problem, it was past warranty. Too bad, so sad, was the response. Not sure how many hours I actually got out of it. Minimal.

    Haven't had it out for quite some time, having scored a tasty Mullard GZ37 to replace it. Currently running a quad of TAD KT88STRs, so popped it back in for a test. Topping out at around 30mV with the bias pots cranked all the way up. So ya, it's basically toast.

    Your results may vary.

    PS ... Sag is NOT something I have to be concerned with using the GZ37. That's got capacity to spare, even driving a quad of KT120s ... doesn't even breathe hard.

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