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Post by edoetsch on Feb 14, 2013 15:01:16 GMT -7
I purchased tubes a while back when the tubestore carried Saratov's Rated at 36 which I think was the recommended value for the Route.
I've done my best to bias with the Weber Bias Rite using a previous post form this site. However, since I am not an electrician I am still a bit worried.
Are there any bias settings that would be dangerous to any part of the amp? Or is the only risk a potentially bad tone setting?
I am using the JJ GZ34 rectifier.
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Post by wubberdubber on Feb 14, 2013 15:06:22 GMT -7
Yes, if the bias is too far off, the tubes could red-plate (which will take out the tube, and possibly a few components attached to the tube socket)...if too low, you won't burn anything up, but it won't sound good, low volume, etc. Main thing is don't bias the tubes into red-plating.
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Post by muzacman02 "Jamie" on Feb 15, 2013 6:12:47 GMT -7
Do you have a Bias rite? if you bias to 36 ma that may be a bit hot but should be fine, i learned the hard way biasing too hot, it causes the amp to be very squashy sounding and the tubes will burn out FAST!, the KT66's are pretty robust however I would have it checked by a Tech if possible just for the sake of not causing other component Damage
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Post by Deleted on Feb 18, 2013 15:29:00 GMT -7
I purchased tubes a while back when the tubestore carried Saratov's Rated at 36 which I think was the recommended value for the Route. I've done my best to bias with the Weber Bias Rite using a previous post form this site. However, since I am not an electrician I am still a bit worried. Are there any bias settings that would be dangerous to any part of the amp? Or is the only risk a potentially bad tone setting? I am using the JJ GZ34 rectifier. If you know the plate voltage you can get a more accurate picture of where your amp needs to be biased. With the amp off, set a voltmeter to at least a 1000VDC. The negative lead of the voltmeter goes on pin 8, and the positive lead goes on pin 3. Turn the amp on, let the amp warm up a bit, and take your reading. At the upper right hand corner of Myles Rose's page Amplifier Blueprinting you'll see a red bar above a picture of Myles with his friend Loni Specter. This red bar contains an Excel sheet which Myles created awhile back. Just type in your VDC on line 6, and the maximum anode rating on line 7 (Gold Lions are 30 watts. Shuguangs are 25). Press enter and you'll get suggested settings on the heat meter (line 11). Any # in the green will work fine, and are safe. Red settings would be considered unsafe for your output tubes or worse. Blue settings are cold. They are not unsafe, but are not an optimal running point for your tubes. You might however like them. When making changes with the bias pot let the amp settle in for 15-20 minutes before taking a reading. The bias takes a little while to settle in. I hope this helps.
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Post by edoetsch on Feb 21, 2013 11:15:44 GMT -7
I have the bias rite from Weber and would prefer not to touch pins to the tube without being instructed in-person first. I combed over the long posting about biasing (somewhere on this site) that I printed out and I am sure I followed it as best I could with the bias rite. I remember that the voltage changed on the meeter as I turned he bias pot. This made adjusting a bit more difficult because I kept having to divide the voltage and mA as I moved the dial.
I am using Saratov's Rated at 36 which I thought were identical to the old groove tubes the Doc was using back in 2006.
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Post by Deleted on Feb 22, 2013 0:42:32 GMT -7
I have the bias rite from Weber and would prefer not to touch pins to the tube without being instructed in-person first. I combed over the long posting about biasing (somewhere on this site) that I printed out and I am sure I followed it as best I could with the bias rite. I remember that the voltage changed on the meeter as I turned he bias pot. This made adjusting a bit more difficult because I kept having to divide the voltage and mA as I moved the dial. I am using Saratov's Rated at 36 which I thought were identical to the old groove tubes the Doc was using back in 2006. The 36 means nothing for your purposes. It is for the tube vendor's purposes only. The Saratov's are a Russian made tube. I'm not sure if it is a 25W or 30W tube (plate dissipation). If you go to the "Ask The Experts" section and "Ask Myles..." he will help you out. Does the Weber tell you the voltage on the plates? You need to know that. Yes it does tell you the plate voltage using the V P setting on the V.I. switch. Just use that number to calculate the bias in mA for each tube. Doc does recommend 36mA per each output tube while using the rectifier you have in there.
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