[chadbang]

 
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I thought this might be the better place for this thread
 
Hi, I just purchased this amp from another member, but, unfortunately, I'm not a Millet expert (nor was the other member). Can Millet Hybrid experts tell me anything about this amp? I know it seems to be a "maxed" version, but that's all. The sound is okay, but nothing special through my Senn HD650s. I was wondering if this is an "approved" build. Also, I see one open slot where the big Nicholson caps are (CR1c and Cr1D)  that usually looks filled on other versions of this amp. Is this built correctly? The amp just doesn't seem to have much air or extension in its frequencies. I've tried all three types of tubes it in. I guess I'd like to know if this is a Kosher build, or some variation which might be missing something?  I'd heard good things about his amp and I just wanted to know if I got a proper build. I can email or post bigger pics if you need them. Thanks alot for your help!
 
16 photos:
 
http://smg.photobucket.com/albums/v336/chadbang/?action=view&current=P1100061.jpg#!oZZ1QQcurrentZZhttp%3A%2F%2Fsmg.photobucket.com%2Falbums%2Fv336%2Fchadbang%2F%3Faction%3Dview%26current%3DP1100084.jpg
 
 
The big picture
 

 
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[jdkJake]

The build looks pretty like a standard BJT DB Max. The unfilled caps at CR1C and CR1D are just that, unfilled. You have the minimum amount of capacitance for that position. One could argue for more, but, whats there should suffice.
 
Most importantly, did you re-bias the amp when you changed the tubes?
 
You should probably recheck the power supply voltage as well as verify the DB bias as well. Until you know the unit is setup correctly and the DB and tubes biased correctly, evaluation of performance is moot.

 

[jdkJake]

BTW, for your HD650's I would stick with the 12AE6 tubes. 

 

[chadbang]

Thank you very much. I wasn't sure, but the more I read today, I was pretty certain it was a DB Max. I listened to it all day and the 12FK6 tubes seemed to sound best to me. As far as biasing the amp, I worried because i have no experience at that at all. I do own a multimeter, but as far as how to use it.... yikes. I guess I'll have to look around youtube for how to bias it. Is it difficult?
 
Quote:

The build looks pretty like a standard BJT DB Max. The unfilled caps at CR1C and CR1D are just that, unfilled. You have the minimum amount of capacitance for that position. One could argue for more, but, whats there should suffice.
 
Most importantly, did you re-bias the amp when you changed the tubes?
 
You should probably recheck the power supply voltage as well as verify the DB bias as well. Until you know the unit is setup correctly and the DB and tubes biased correctly, evaluation of performance is moot.

 

 

[jdkJake]

http://www.diyforums.org/MAX/MAXsetup.php

Just take your time and be careful as the amp is live when you do this process. Ideally, the DB will not need to be tweaked. Usually, once set, they hold fine. The tube bias needs to be changed each and every time you change a set of tubes. The bias can be radically different for each and every set of tubes.

Generally, most builds now bring out test points to the back of the chassis to make this process easier. In your case, you will have to go "old school".

Again, just take it slow.