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    Rectifier Tube Comparisons

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    audiobill

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    Rectifier Tube Comparisons

    Post by audiobill on Fri Jan 09, 2015 10:49 am

    Over at Headfi.org:

    http://www.head-fi.org/t/694525/dubstep-girls-massive-5ar4-5r4-5u4g-rectifier-review-comparison-rectifer-tube-rolling-thread

    Bob Latino
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    Re: Rectifier Tube Comparisons

    Post by Bob Latino on Sat Jan 10, 2015 9:14 am

    All of what the author is saying about each rectifier tube pertains to headphone amps and not audio amps that use speakers. I doubt in a double blind test that most people can hear differences in rectifier tubes UNLESS that rectifier tube is being used near the limit of its ability to produce DC for the amp. When really pressed hard to produce DC for the amp (real high volume levels) then yes - some rectifiers are better than others. I doubt that at normal listening levels the author of that article could tell the difference between one rectifier and another. If you are the person making the switch from one rectifier to another then you know which rectifier is in the amp at that time. Your listening will be influenced by that fact. At least he should have someone else do the rectifier switch behind a curtain (blind test) and then have a panel of listeners write down what they hear from this rectifier when they listen to the amp. Every time I see a "test" like this I put little faith in the results that are achieved from doing the test ...

    Bob

    sKiZo

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    Re: Rectifier Tube Comparisons

    Post by sKiZo on Sat Jan 10, 2015 3:16 pm

    There's such a thing as over stressing a rectifier too ...

    ... or at least that's my unscientific opinion comparing the 5AR4 to a GZ37 in my ST120 ... What a Face

    The amp sounds a bit pinched trying to drive a quad of KT120's with the 5AR4. An old production Mullard GZ34 tends to hold up much better when pushed, but the GZ37 barely breaks a sweat no matter what I throw at it ... and I throw it !hard! listening to prog rock with dbx expansion and bass synth. I'll save the Mullard GZ34 for special occasions.

    Even if it's all in my head, that's where the magic happens anyway, right?

    PS ... still haven't seen any reviews for the new production Mullards ... supposed to be a close match mechanically, but I do know one of the problems with any current tubes is the lack of the rare metals that gave the old tubes their special flavor. Last I heard, China's cornered around 97% of the rarest of the rare ...

    Gregg R.

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    Tube Rectifier Comparison

    Post by Gregg R. on Sat Jan 10, 2015 10:57 pm

    I spent last night plowing through DubstepGirl's rectifier compare; basically she/he prefers the rare-pricey ones to less costly tubes!

    I am not sure how you would perform a valid tube rectifier double-blind comparison. You would need to shut down the amp, wait for the tube to cool, insert the next tube, warm up the new tube, etc., etc. By this time you'll probably prefer the one that sounds louder/brighter. Back in the mid 70s when I sold hi-fi gear, we used a similar technique to dupe customers into buying high mark-up equipment: turn up the volume, treble and bass, and write up the sales order!! This was mainly for loudspeakers: all amps sounded the same, right!! Julian Hirsch said so. Somewhere along the line I developed scruples and got out of the hi-fi business. I remained unemployed for a long time.

    When I replaced the Sovtek 5AR4 in my VTA ST-70 amp with a Weber WZ-68, I heard a clear and unambiguous improvement in focus and clarity.

    skriefal

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    Re: Rectifier Tube Comparisons

    Post by skriefal on Sat Jan 10, 2015 11:34 pm

    Gregg R. wrote:I spent last night plowing through DubstepGirl's rectifier compare; basically she/he prefers the rare-pricey ones to less costly tubes!

    But but... they must be better. They're more expensive!

    This is why I read sighted reviews like this with plenty of grains of salt nearby...

    xdodge

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    Re: Rectifier Tube Comparisons

    Post by xdodge on Tue Jan 27, 2015 1:10 am

    OK I just blew my JJ GZ34s in my ST 70, about a year old and I run it hard !!!! Is there any one that would do better then another? If I have to order might as well put in the toughest one I can get.

    Thanks

    peterh

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    Re: Rectifier Tube Comparisons

    Post by peterh on Tue Jan 27, 2015 1:40 am

    A solid state would be more resilient. Either via soldering 2 1n4007 or purchasing a "cupper"

    xdodge

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    Re: Rectifier Tube Comparisons

    Post by xdodge on Tue Jan 27, 2015 3:16 pm

    peterh wrote:A solid state would be more resilient. Either via soldering 2 1n4007 or purchasing a "cupper"

    What exactly is a "cupper" ??

    peterh

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    Re: Rectifier Tube Comparisons

    Post by peterh on Tue Jan 27, 2015 3:41 pm

    xdodge wrote:
    peterh wrote:A solid state would be more resilient. Either via soldering 2 1n4007 or purchasing a "cupper"

    What exactly is a "cupper" ??

    http://www.webervst.com/ccap.html ( my bad spelling, sorry )
    The "copper" simply replaces gz34. The alternative ( 2 x 1n4007 ) needs to be soldered in place.

    deepee99

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    Re: Rectifier Tube Comparisons

    Post by deepee99 on Tue Jan 27, 2015 6:40 pm

    The Weber 68s work for me. Pmail tmadden on this board on some mods he's made to them so they don't die from internal heat. Unless you can afford NOS GZ-33s they are the cat's meow.

    skriefal

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    Re: Rectifier Tube Comparisons

    Post by skriefal on Tue Jan 27, 2015 9:30 pm

    Anyone like to offer Copper Cap mod services for those of us who don't have the tools (drill, vise, etc) to do it ourselves? Smile

    kaner

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    Re: Rectifier Tube Comparisons

    Post by kaner on Tue Jan 27, 2015 10:57 pm

    Bob is spot on. The rectifier's job is to start the process of turning AC into DC. The consequence of failure is hum or sag. Guitar amp guys can argue forever about sag and where it comes from, but in an audio amp all we are looking for is clean B+. Rectifier, Weber, diodes, whatever it takes. Just give me a clean B+ !!!

    xdodge

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    Re: Rectifier Tube Comparisons

    Post by xdodge on Wed Jan 28, 2015 12:58 am

    So been doing some searching, would this be an option???

    Nobsound® 2Pcs Shuguang 274B vacuum tubes new replacing 5AR4 5U4 5Z3

    http://www.amazon.com/Nobsound%C2%AE-Shuguang-vacuum-tubes-replacing/dp/B00O8WNR9C/ref=sr_1_18?ie=UTF8&qid=1422420692&sr=8-18&keywords=5ar4

    They look nice, but only 4 pins on bottom.

    skriefal

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    Re: Rectifier Tube Comparisons

    Post by skriefal on Wed Jan 28, 2015 1:08 am

    No. Those cannot handle as much current as a 5AR4. They might work in a pre-amp or other piece of equipment that doesn't push the rectifier to its limits. But not in an St-70.

    deepee99

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    Re: Rectifier Tube Comparisons

    Post by deepee99 on Wed Jan 28, 2015 12:05 pm

    skriefal wrote:Anyone like to offer Copper Cap mod services for those of us who don't have the tools (drill, vise, etc) to do it ourselves? Smile
    As I said in my previous post, just message Troy, who is tmadden on this board. His mods to the copper-caps have certainly worked for me. He's a good guy to know in all matters Dynaco/VTA etc.

    dmag

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    Re: Rectifier Tube Comparisons

    Post by dmag on Fri Jan 30, 2015 3:46 pm

    Ive had enough problems with the JJ  rectifier to switch to Sovtek. They seem to hold up much better.
    Genelex has been getting good results from a couple people Ive talked to. More money though.

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