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-   -   Art Audio Quintet MK1 EL34 PP resistor value (http://www.diyaudio.com/forums/tubes-valves/232500-art-audio-quintet-mk1-el34-pp-resistor-value.html)

ken1967 21st March 2013 09:01 AM

Art Audio Quintet MK1 EL34 PP resistor value
 
Hello, I have been enjoying an Art Audio Quintet MK1 EL34 PP ( the one with switch Triode & Ultra Linear) for several years now since I bought it second hand several years in London.

This liittle amp used 2x EL34 per channel and run 15w with triode and 25w with Ultra linear.

Now one of the resistor for EL34 is burnt. The resistors used stated 560 ohm. However I am not sure if it is the original one as the amp is some 20 years old and some parts may have changed since. The circuit diagram I can find online how 470 ohm. Which one should be the right one? Thanks

Ken

DF96 21st March 2013 10:31 AM

You don't say whether this is the cathode resistor or (possibly) the screen grid resistor.

ken1967 21st March 2013 04:44 PM

Should be the cathode resistor, sorry not too good at circuit but it link to the one of the pins of the tube...

knickle 21st March 2013 05:24 PM

If the resistor really is a 470 R, sure is screen grid resistor, not a cathode one, but the output power as UL for a pair of EL34 isnīt too low? What is the plate voltage ?

DF96 21st March 2013 06:04 PM

The standard Mullard 5-20 cathode resistor for UL EL34 is 470R (5W?), but this runs the valves quite hot. Provided you don't intend doing continuous sine wave testing then 560R will be cooler and, perhaps, slightly better on normal music.

The screen grid resistor could be 470-1k - value not too critical, maybe 2W dissipation.

DavesNotHere 22nd March 2013 02:27 PM

I have subbed 560 ohm in place of 470 in amps that the b+ jumped too high due to line voltage changes.

I use Mills mra-12 560 ohm resistors in that location.

and there is a few places online to get them one that I use often is Parts ConneXion - The authority on hi-fi DIY parts and components.

ken1967 27th March 2013 04:50 PM

So it seems 560 ohm ( 15w ) should be better than the 470 ohm (15w ), right?

Ken

Tesla88 28th March 2013 11:45 AM

You have a stereo amp with a total of 4 power tubes in the same configuration and you burned just one resistor , screen resistor, so just measure or simply look at the screen resistors of the other 3 EL34 tubes , they are the same...


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