VVR Circuit Schematic
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VVR Circuit Schematic
I've used the search function here and have not been able to find a posted VVR schematic. Is this something that is readily available?
Re: VVR Circuit Schematic
Here ya gowallybob wrote:I've used the search function here and have not been able to find a posted VVR schematic. Is this something that is readily available?
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Re: VVR Circuit Schematic
Many thanks Dana!
Re: VVR Circuit Schematic
This may help.
http://ampgarage.com/forum/viewtopic.php?p=65052#65052
http://ampgarage.com/forum/viewtopic.php?p=65052#65052
Tom
Don't let that smoke out!
Don't let that smoke out!
Re: VVR Circuit Schematic
Thanks for the info guys. I'm a little hesitant about hanging a pot off the B+ even though it sound like you guys have done it a bunch of times. If you had only two or three levels of voltage reduction (with a switch) what would they be, i.e., 100% & 50%; 100%, 75%, and 30%; etc.?
Re: VVR Circuit Schematic
Wallywallybob wrote:Thanks for the info guys. I'm a little hesitant about hanging a pot off the B+ even though it sound like you guys have done it a bunch of times. If you had only two or three levels of voltage reduction (with a switch) what would they be, i.e., 100% & 50%; 100%, 75%, and 30%; etc.?
If you measure the current flow through a 1 meg pot to ground with 500v on it (That is what the pot is rated at by the mfg) you get .5ma .5ma x 500v = .250w or 1/4 watt. So the 1/2 watt pot is only running at 1/2 it's rated power @ it's mfgs rated voltage. Since most TW are running 400v or less there is even more of a safety margin. Now bolt that pot to a grounded metal chassis and put a plastic knob on it to further isolate your human fingers and I really don't know how it could be any safer. I would be more worried about the standby switch shorting out as it has all of the current from the power supply going through it and also has high voltage on it only there is no plastic knob . If you aren't afraid to reach over and flip a standby switch then why would you be worried about the pot? Just my 2 cents
Re: VVR Circuit Schematic
Double post
Server error. Seems like more often than not, when I post I get this debug error thing and then when I go back it has double posted. Anyone else having this problem??
Server error. Seems like more often than not, when I post I get this debug error thing and then when I go back it has double posted. Anyone else having this problem??
Re: VVR Circuit Schematic
Yuuup!UR12 wrote:Double post
Server error. Seems like more often than not, when I post I get this debug error thing and then when I go back it has double posted. Anyone else having this problem??
Only too bad that it does'nt count for a post.
I was told that knobody would take me seriously unless i have at least 1000 posts...
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Re: VVR Circuit Schematic
Thanks for the circuit schema UR12.
Yes it does the same thing to me but not as frequently lately. Today it's taken a lot longer to post my messages but it hasn't "hung-up".
Yes it does the same thing to me but not as frequently lately. Today it's taken a lot longer to post my messages but it hasn't "hung-up".
All excellent things are as difficult as they are rare__B Spinoza
Re: VVR Circuit Schematic
I've been using the VVR on a cathode biased amp and have been very happy with it. If I use it on a fixed bias, do I just get one of those dual pots and divide the bias supply with the other pot? I'm assuming the other pot will also have the 100K resistor (i.e. in series with pot and goes to ground) hanging off of it so that the bias supply can drop down to 10%. Is that correct?
Thanks!
-FunkyE9th
Thanks!
-FunkyE9th
Re: VVR Circuit Schematic
There is a little more to it than that. What you propose may or may not work depending on the bias circuit in the particular amp.FunkyE9th wrote:I've been using the VVR on a cathode biased amp and have been very happy with it. If I use it on a fixed bias, do I just get one of those dual pots and divide the bias supply with the other pot? I'm assuming the other pot will also have the 100K resistor (i.e. in series with pot and goes to ground) hanging off of it so that the bias supply can drop down to 10%. Is that correct?
Thanks!
-FunkyE9th
Re: VVR Circuit Schematic
Bummer...I was hoping it was that simple. I guess I gotta look into it some more...Thanks!
Re: VVR Circuit Schematic
Last edited by Tubetwang on Fri Oct 24, 2008 2:03 pm, edited 1 time in total.
Re: VVR Circuit Schematic
If putting a VVR on my cathode biased tweed Super clone, can I use it like zener diode for limiting max voltage too? Darn 365-0-365 PT gives me 440 on the plates. My 6V6 Super clone has a 342-0-342 Pt and 400v on the plates. Would you then use a fixed resistor in series with the pot ?