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    Weber WZ68 now NOT recommended on Weber website!

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    sKiZo

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by sKiZo on Sun Sep 27, 2015 12:55 pm

    arledgsc wrote:
    If B+ has increased closer to 550V I will wire up my unused ST120 rectifier heater winding as a bucker with the incoming line voltage to effectively reduce the AC coming in about 5V.  This should reflect to 15-20V less HV AC at the rectifier input.  

    Hadn't thought of that ... I made an external bucker instead, using a transformer that's good for 6a. Will that spare winding handle the current?

    Wonder if you could wire up that extra heater winding for hot switching? Turn it on when needed, or not. I know my line voltage was at 124+vac when I first got going here due to a recent upgrade in the grid for a new housing development down the road. Power company has since got things back to normal, and the bucker is out of the loop ... for now anyway.
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    Kentley

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by Kentley on Sun Sep 27, 2015 5:24 pm

    Today I switched out rectification in my VTA ST-120. I replaced my trusty Mullard GZ-37 with the Weber WS1. The sound is comparable. One caveat -- lower your bias adjustments to minimum before you switch to the WS1. What used to be spot-on .54 VDC with the tube when the pots were at 2 o'clock became dramatically different with the Weber and now .54 VDC is achieved with the pots at 10 o'clock. Caveat rector!
    I've run it at moderate volume for an hour now and the temp. on the copper-cap reads at 156F. Way cooler than the WZ-68 which I melted down several months ago!
    DON'T TRY THE WS1 if you don't have the time-delay relay installed -- unless you wish to be blowing output tubes left and right. Bad pun intended. It blasts B+ voltage instantaneously -- no delay whatsoever.
    The WS1 is less than $20 from Weber Speaker Co. That is a good thing.
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    arledgsc

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by arledgsc on Sun Sep 27, 2015 6:47 pm

    Good job Kentley!  I probably need some form of inrush current reduction with the straight diode replacement.  I will work on that.  The lights dim a little for a second when the delay relay kicks in - more than usual.

    Skizo I wish the bucker idea with the main transformer was mine as that is a brilliant solution.   I got the notion from our forum member "peterh".   I'm sure a in/out switch would work on the bucker but would recommend only changing with power off and recheck bias afterward.
    http://dynacotubeaudio.forumotion.com/t2403-howto-cut-5v-from-the-mains-line?highlight=line+voltage
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    Roy

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by Roy on Thu Jan 18, 2018 4:36 pm

    Reading up on the rectifier options for the ST-120 build coming across this thread now and reading the current page for the ws1 rectifier on their site there is now an option for having a thermistor included in it for a few seconds warm up period - so would this ws1 with the thermistor require the delay board or not?
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    deepee99

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by deepee99 on Thu Jan 18, 2018 11:09 pm

    Roy D wrote:Reading up on the rectifier options for the ST-120 build coming across this thread now and reading the current page for the ws1 rectifier on their site there is now an option for having a thermistor included in it for a few seconds warm up period - so   would this ws1 with the thermistor require the delay board or   not?
    IMHO, the delayed start-up board should be required on all VTA amps, regardless of rectifier style. It's the cheapest insurance money can buy. Also Roy's "yellow sheet" mod. From there your options are limitless.
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    Kentley

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by Kentley on Thu Jan 18, 2018 11:35 pm

    I agree with deepee. The thermistor may provide a modicum of delay, but it may not provide enough (how many seconds in "a few"?).
    The TDR allows you to choose any rectifier without concern. It's worth the piddling extra expense.
    I've been running the naked Weber WS-1 for well over a year (with the TDR) and the real concern is, without sag resistors, your B+ may rise above the prescribed max. of 410 VDC. This will depend on your line AC. If that stays below 118, like mine (thank some god or other!) you should be fine.
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    Roy

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by Roy on Fri Jan 19, 2018 4:20 am

    hmm ok, I will put the TDR on the list.. thanks deepee, Kently!
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    Roy

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by Roy on Fri Jan 19, 2018 5:01 am


    so   my knowledge of circuits is not yet up to the point where when I look at the TDR board on the VTA site I can determine all the functions so
       would the TDR also eliminate 'filament flash' such as detailed in this circuit in the Carlsons Lab video?

    *edit* re reading the tubes4hifi page on the TDR unit, I think the answer is   yes =}
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    peterh

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by peterh on Fri Jan 19, 2018 10:17 am

    Roy D wrote:
    so   my knowledge of circuits is not yet up to the point where when I look at the TDR board on the VTA site I can determine all the functions so
       would the TDR also eliminate 'filament flash' such as detailed in this circuit in  the Carlsons Lab video?

    *edit* re reading the tubes4hifi page on the TDR unit, I think the answer is   yes =}
    Gaasp ..
    This guy don't even know that telefunken tubes are not mullards, and that the
    kind of "flash" discussed is limited to mullards ( phillips volvo etc)
    BTW, the mullards don't exhibit broken filaments, thus this issue is a non-issue.
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    Roy

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by Roy on Fri Jan 19, 2018 10:24 am

    yay I like non issues ^^ But overal I gather this TDR does indeed slowly up the voltage on the heaters then enables the high voltage to come on which will indeed help the lifespan of the tube set which is a good thing. The only questionmark I had was the remark that the WS-1 has some construction differences which may result in 'not good things' when the main voltage rises too much..
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    deepee99

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by deepee99 on Fri Jan 19, 2018 3:03 pm

    Roy D wrote:yay    I like non issues ^^   But  overal I gather  this TDR does indeed slowly up the voltage on the heaters then enables the high voltage to come on which  will indeed help the lifespan of the tube set which is a good thing. The only questionmark I had was the remark that the WS-1 has some construction differences which may result in  'not good things' when the main voltage rises too much..
    Roy, not sure about that with the TDR. I think the filaments light straightaway, burn for about 15 seconds, then the B+ comes on. Bob L,, Roy M., correct me if I'm wrong here. I'm not aware of an off-the-shelf device that defers filament lighting, although after watching your video it seems like a good idea.
    Unlike light-bulbs, tube filaments are pretty tough so I don't believe much thought is put into their longevity.

    nmchiefsfan

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    Join date : 2012-03-21

    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by nmchiefsfan on Fri Jan 19, 2018 3:52 pm

    The TDR delays the application of the High Voltage (B+) to the plates of the tubes. The voltage is applied instantly once the time limit has been met. It is used to allow the output tubes a chance to warm up prior to having high voltage applied to them. Another nice feature is a blip in AC power will cause the TDR to reset and delay the high voltage again so it helps with fast cycle issues.
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    deepee99

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by deepee99 on Fri Jan 19, 2018 4:23 pm

    nmchiefsfan wrote:The TDR delays the application of the High Voltage (B+) to the plates of the tubes. The voltage is applied instantly once the time limit has been met.  It is used to allow the output tubes a chance to warm up prior to having high voltage applied to them. Another nice feature is a blip in AC power will cause the TDR to reset and delay the high voltage again so it helps with fast cycle issues.  
    Yes, I neglected to mention that. I prefer the protection of a manual-reset GFCI which shuts everything down at a power blip, and when the lights come back on you can then re-set it. Between the TDR and the manual re-set GFCI I've never lost a rectifier, cap or power tube, and power fluctuations are regrettably frequent during winters here.
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    sKiZo

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by sKiZo on Fri Jan 19, 2018 5:58 pm

    Roy D wrote:Reading up on the rectifier options for the ST-120 build coming across this thread now and reading the current page for the ws1 rectifier on their site there is now an option for having a thermistor included in it for a few seconds warm up period - so   would this ws1 with the thermistor require the delay board or   not?

    Point of order - wouldn't a WS1 with a thermistor be a WZ68? It's the thermistor in that what causes the meltdowns.

    ... which I might add was never a problem here ... then again, my custom chassi has a whole lot more air space for convection cooling so it won;t go nuclear ...

    PS - I've got the manual reset GFCI adapter AND a GZ37 AND the "yellow sheet mod" AND a thermistor on the main AC line in ... do I still need a time delay board"  ;-}
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    deepee99

    Posts : 1908
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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by deepee99 on Sun Jan 21, 2018 1:03 pm

    sKiZo wrote:
    Roy D wrote:Reading up on the rectifier options for the ST-120 build coming across this thread now and reading the current page for the ws1 rectifier on their site there is now an option for having a thermistor included in it for a few seconds warm up period - so   would this ws1 with the thermistor require the delay board or   not?

    Point of order - wouldn't a WS1 with a thermistor be a WZ68? It's the thermistor in that what causes the meltdowns.

    ... which I might add was never a problem here ... then again, my custom chassi has a whole lot more air space for convection cooling so it won;t go nuclear ...

    PS - I've got the manual reset GFCI adapter AND a GZ37 AND the "yellow sheet mod" AND a thermistor on the main AC line in ... do I still need a time delay board"  ;-}
    Depends on your OCD levels. Me, I'd get one Smile

    eickmewg

    Posts : 87
    Join date : 2014-08-29

    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by eickmewg on Mon Jan 22, 2018 7:40 am

    I installed a TDR on my ST120. At the time I had a GZ34 rectifier in the amp. The rectifier arc'ed when the high voltage kicked in. I asked Roy about this and my recollection is that he suggested I shouldn't use a tube rectifier with the TDR. I then put my WZ68 back in the amp. The GZ34 got put in my Magnavox 9304 amp where it has been happy and works fine. Maybe Roy can refresh my memory.

    I think in addition to the thermistor, a WZ68 has some big cement resistors for some voltage sag missing from the WS1.
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    pedrocols

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by pedrocols on Wed Jan 24, 2018 12:03 am

    I have been running the same WZ68 on one of my VTA 125s for over two years. I had to replace it in the other one but even that one lasted over a year.
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    Peter W.

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by Peter W. on Wed Jan 24, 2018 10:12 am

    Hmmmm.... This is going to look as if I am engaging in apostasy coming from me - but for those running their various amps without a cage, thereby exposing all to heat and voltage, it would seem that there is no particular reason to put anything on top of the rectifier, copper, solid, drilled or otherwise.

    And, as there is at least some real-estate around the rectifier socket, building the components into a nice finned heat-sink seems to make sense. And with perhaps phenolic or silicon lagging, it could even be reasonably safe.

    Thoughts?

    http://kam-alu.com/pic/other/2013-10-22-19-32-017.jpg

    eickmewg

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    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by eickmewg on Wed Jan 24, 2018 10:24 am

    I have drilled my WZ68 with three 1/4 inch holes on two opposite sides and a 1/4 inch hole on the top. I also have a 6 inch boxer fan that I use to help cool the power transformer. With both of these, I can easily touch the top of the WZ68 for a second or two with no discomfort. So, it seems to run at a nice, relatively cool temperature.

    Dogstar

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    Join date : 2014-06-23

    Re: Weber WZ68 now NOT recommended on Weber website!

    Post by Dogstar on Mon Jan 29, 2018 2:21 pm

    About a year after I got my amp my Sovtek rectifier I got with the amp died..I forgot if it red plated or just stopped working and as a solution to my situation it was recommend that I try a Weber WZ68...so I got two and popped one it that worked flawlessly for over a year. I did eventually put a Gold Lion rectifier in that works flawlessly but a while ago I was experimenting with a 6SN7 tube with an adapter in the center position on the board. As a precaution I put the original WZ68 in and so far the amp is still running flawlessly.

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