Sean- As noted, the Joule amps outboard power supply module IS a variac and 85-90 v is the recommended power as per the manual. Thanks for the tip, Sean, I did not know that the AVS 2000 produces a clicking sound; that does not seem to be what I want! I will contact Judd at Joule after the weekend, but just wanted to see if any of 'youse guys' had any ideas for me.
Voltage regulation for Joule amps
I am wondering what if anything others are using for locking the AC voltage for their Joule amps. Based on the built-in voltmeter, my AC varies substantially, when I have the variac set for 89 volts and then the output tubes biased at 27-28, I find that it can be down as low as 82 volts as short while later, with the bias dropping down to 22-23!! I do not have the amp on a dedicated line and can try that next, after the XMAS lights are gone, but I'm betting it is a problem with the power delivered to my house. The difference in price between a Monster 2000 and an Exact Power 15a is almost $1K!! Any thoughts? TIA and Merry Kwanzachristmakah>
Showing 5 responses by swampwalker
Sean, I know that I am not technically knowledgeable to go around making changes in this unit, if what you are saying is that a "regulated power supply" would be a replacement for the variac. esp. since the variac is connected to the main amplifier by two different power cords with different terminations (one male and one female, IIRC). That is the reason I was looking for something like the the Monster AVS 2000 of the Exactpower since I think what I need is something that would supply a constant voltage. The fluctuation at the amp (downstream of the variac) is about+1, -5 volts. I just double checked the manual and the indicated range is about 83-87 volts. It generally seems to sag more than go up, both in the magnitude of the change and the frequency of the change (i.e., it most frequently reads below the initial nominal setting). This causes the bias on the output tubes (6C33C-Bs) to drop from 27/28 to 23/24, and compromises the sound. The variac is near a warm air outlet and the amp itself is on an outside wall. Of course, it runs quite hot and I am sure alters the ambient temp around itself by several degrees. The variac is about 2-3' away and slightly lower down, but as I said, close to a warm air duct. Could these temperature fluctuations be having an effect on the voltage the variac delivers? As you can see, my knowledge of things electrical is quite limited. TIA. I will, of course, contact Judd at Joule tomorrow. |
I understand that the bias on the tubes will wander and I'm not too concerned about that. What I am concerned about is if the voltage wanders and the bias wanders and they both wander in the same direction, I will either end up with the tubes dramatically under-biased, resulting in a too-laid-back presentation, or dramatically over-biased, resulting in (I think) premature wear and/or failure (which I am told can be quite dramatic on this OTL amp!). |
Jsl- Rites? Not sure what that (those) are. My amp is a VZN-80, which I imagine is basically a half of a pair of VZN-160s. I am told it can be modified to a monoblock, but based on my room and ancillary equipment, I cannot imagine going any further up the line in terms of power!! The recommended voltage is 83-87v. |
Thanks, J. I will give that a try when my amp comes back from a trip to SC.:-( Unfortunately, something appears to have given out. See my other thread for details. http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1104378496&openmine&zzSwampwalker&4&5#Swampwalker |