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    Tube rectified

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    Captain Coconut

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    Tube rectified

    Post by Captain Coconut on Sat Oct 14, 2017 7:40 pm

    Just wondering why the M125 and VTA120 use tube rectification and not solid state. There seem to be arguments, pro and con, with the two methods; but in this case, is tube rec what the audiophile demands? Nostalgia maybe? Sound?

    Dogstar

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    Re: Tube rectified

    Post by Dogstar on Sat Oct 14, 2017 10:38 pm

    I've used both a real tube rectifier and a solid state Webber rectifier in my ST-120. I got the Webber when the tube rectifier I had went bad and I used it with the TungSol KT-120 I also installed at the time. I really enjoyed the sound.

    I'm now using a Genelex GZ34 rectifier with the Gold Lion KT-88's. I think the amp sounds ok...but to be honest I like the sound with KT-120's better. I don't think the rectifiers have as great an affect as the output tubes.
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    Kentley

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    Re: Tube rectified

    Post by Kentley on Sat Oct 14, 2017 11:54 pm

    IINM, the goal of VTA  and tubes4hifi design was to diverge as little as possible from the original Dynaco product. That meant keeping the general layout. Such things as the on/off switch in the rear, the unusual tube socket for bias, the inputs on the front, and the tube rectifier were retained. The quad cap, the transformers, and the driver board were modified and beefed up only as necessary while retaining the look and feel of the originals (Dyna ST-70 and MkIII). So yes, in a manner of speaking it was a nostalgic concept, at least. One of the beauties of this approach is that one with a real vintage Dyna unit could upgrade and update his equipment without throwing out the baby with the bathwater.


    Last edited by Kentley on Sun Oct 15, 2017 12:04 am; edited 1 time in total (Reason for editing : gramma)
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    Bob Latino
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    Re: Tube rectified

    Post by Bob Latino on Sun Oct 15, 2017 8:46 am

    Captain Coconut wrote:Just wondering why the M125 and VTA120 use tube rectification and not solid state. There seem to be arguments, pro and con, with the two methods; but in this case, is tube rec what the audiophile demands? Nostalgia maybe? Sound?

    Set up the way they are now, all the VTA amps can use either TUBE or SOLID STATE rectification. The Weber WZ68 and WZ34 solid state rectifiers plug right into the tube rectifier socket. Whether you use a tube or solid state rectifier is your choice. If (1) your room is large, (2) your speakers are relatively inefficient and (3) you play your music really loud much of the time, then maybe you should try a solid state rectifier? A tube rectifier will sag the B+ high voltage somewhat at high volume levels whereas a solid state rectifier will have little to no B+ sag at higher volume levels. Besides the Weber WZ rectifiers, you can also use the T-SSR01 solid state rectifiers made by CE Distribution and the Weber WS1. While the Weber WZ68 and WZ34 have a built in 3 to 5 second delay to mimic (somewhat) a tube rectifier warm up, the T-SSR01 and WS1 have no delay built in. You should use the the VTA TDR (Time Delay Relay) board with the T-SSR01 and WS1. This will allow the filaments to warm up on all the tubes for about 17 seconds before high voltage is applied. IMHO you can use the Weber WZ68 without the time delay relay board. The shorter delay built into the WZ68/WZ34 has proven to me over the past 10+ years to be enough of a delay to give a normal tube amp start up.

    Bob
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    tubes4hifi
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    Re: Tube rectified

    Post by tubes4hifi on Sun Oct 15, 2017 4:14 pm

    for power amplifiers, a SS replacement for the rectifier tube is probably a good idea.
    But IMHO, for preamps, I can hear a sonic difference (for the better) using a tube rectifier rather than a couple of SS diodes.
    Many years ago I modified several GGP preamps that were considered really nice, put in a tube rectifier and they sounded ALOT better,
    takes away alot of the harshness of diode power supplies and huge filter caps.
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    jfine

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    Re: Tube rectified

    Post by jfine on Wed Oct 18, 2017 8:27 pm

    Bob Latino wrote:
    A tube rectifier will sag the B+ high voltage somewhat at high volume levels whereas a solid state rectifier will have little to no B+ sag at higher volume levels.
    Bob

    I wonder if the yellow paper diode mod is applied to an M125, is this still true using a tube rectifier?

    Dogstar

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    Re: Tube rectified

    Post by Dogstar on Thu Oct 19, 2017 6:58 am

    The Tubelab.com Simple Single Ended amp I'll be building until I die has the option of eliminating the need for an external rectifier (tube or otherwise) by adding two diodes to the PC board.

    To me it seems the rectifier does not add or detract from the sonic quality of a tube amp through my not so scientific experiment with my TungSol KT-120 tubes. Perhaps others can hear a difference. I had to have a hearing test for my job and despite working as a manufacturing engineer for a company that uses CNC machining centers for fabricating parts. I'm out in the shop quite a bit and despite that, along with target shooting as a hobby my hearing is fairly well...though I do hear ringing that is noticeable when it's quiet which is why I listen to music at night to help me sleep.
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    Captain Coconut

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    Re: Tube rectified

    Post by Captain Coconut on Thu Oct 19, 2017 5:47 pm

    It seems like some tube aficionados would rather die than use a diode, while the EE crowd sees the use of rectifiers as unreliable, heat emitting, old technology. Tube rectifiers look cool though!
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    Tubes4ever

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    Re: Tube rectified

    Post by Tubes4ever on Thu Oct 19, 2017 10:51 pm

    Captain Coconut wrote:It seems like some tube aficionados would rather die than use a diode, while the EE crowd sees the use of rectifiers as unreliable, heat emitting, old technology. Tube rectifiers look cool though!

    I'm one of those aficionados. Just got a new GZ33 and it looks very cool!!
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    kaner

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    Re: Tube rectified

    Post by kaner on Sun Oct 22, 2017 8:32 pm

    Rectifier sag in a guitar amp is HUGELY important. The next time you hear a song end with a long electric guitar power chord you will know what rectifier sag sounds like. It's like a slow waffle in and out. Guitar tube amps push their tubes to (and past) their limits. In fact, that awesome Jimmy Page electric guitar sound is the tubes being pushed into distortion. The reason the best guitar amps still use tubes is because when a tube distorts, it creates a harmonic distortion. A wonderful fallout of early guitar amp designers like Leo Fender trying to save a bit of money on production costs, only to have guitarists run the volume up towards the max.

    Audio amps try to eliminate distortion and sag. The VTA designs are structured to run all of the tubes within their limits. Rectifiers, preamp tubes, power tubes. So when Bob suggests a SS rectifier tube for listeners that push the volume on their audio amps, that's why. Sag is awesome in a guitar amp, but undesirable in an audio amp.
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    Captain Coconut

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    Re: Tube rectified

    Post by Captain Coconut on Mon Oct 23, 2017 7:09 pm

    If you were designing a low power (say, 15-20 watts) tube amp, and you weren’t going to push it, would you use a tube rectifier? Is diode noise a real issue?
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    kaner

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    Re: Tube rectified

    Post by kaner on Tue Oct 24, 2017 12:24 am

    Personally I rectify with vacuum tubes and do not add the diode mod.  I can't bring myself to burning that candle just for the ambiance...
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    Tubes4ever

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    Re: Tube rectified

    Post by Tubes4ever on Tue Oct 24, 2017 12:46 am

    kaner wrote:Personally I rectify with vacuum tubes and do not add the diode mod.  I can't bring myself to burning that candle just for the ambiance...

    Totally agree.  I want my rectifier tube to actually do the rectifying.  Plus zero switching noise...which you have to put your ear right up to the speaker to hear with no input signal...but still...

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