minasu Posted October 15, 2008 Share Posted October 15, 2008 Hi All, I just buy Luxman MQ-80 with failure 6336s. Now I already replaced good condition (about 70%) 6336s, now I would like to improve its sound by adjust DC balance and Bias. Could you show me how to get MQ-80 manual, schema, DC Balance and Bias adjustment? I am also looking to buy two NOS 6336s. Your assistance is very much appreciated. Hoang Quote Link to comment Share on other sites More sharing options...
Tarheel Posted October 17, 2008 Share Posted October 17, 2008 Welcome to the forum Hoang. You could try hifiengine.com/ for your manual. They have over 2500 manuals available. Chuck Quote Link to comment Share on other sites More sharing options...
seti Posted October 17, 2008 Share Posted October 17, 2008 Forum member IBSlammin knows of someone in the US who services Luxmann gear. You might trying sending him a PM. He has some killer Luxmann tubes amps. I would try Brent Jesse at audiotubes.com or ebay for the 6336 tubes. I don't know the seller but here are 3 6336 tubes on ebay http://cgi.ebay.com/Tubes-3-new-6336-Tung-Sol-Factory-Matching-NOS-USA_W0QQitemZ370070436995QQcmdZViewItem?_trksid=p3286.m20.l1116 Quote Link to comment Share on other sites More sharing options...
minasu Posted October 17, 2008 Author Share Posted October 17, 2008 Chuck, Thank you for your information, I checked the website but they don't have MQ-80 manual. But I can download manual for my preampli CL-32. Thanks Hoang Quote Link to comment Share on other sites More sharing options...
minasu Posted October 17, 2008 Author Share Posted October 17, 2008 Seti, Thank you for your ebay information. I cannot find any the user as your mention "IBSlammin" on forum. Could you check again? Quote Link to comment Share on other sites More sharing options...
jbsl Posted October 18, 2008 Share Posted October 18, 2008 Link to a Luxman Yahoo group that can probably answer most of your questions. Sign up and post question. http://tech.groups.yahoo.com/group/luxman/ Quote Link to comment Share on other sites More sharing options...
seti Posted October 18, 2008 Share Posted October 18, 2008 Seti, Thank you for your ebay information. I cannot find any the user as your mention "IBSlammin" on forum. Could you check again? I'll send him an email regarding this thread. Quote Link to comment Share on other sites More sharing options...
artto Posted October 18, 2008 Share Posted October 18, 2008 minasu, welcome to the Forum! I have a couple of friends that also use Luxman but are a little more guru than I. I've emailed them. They probably have the answer & I'll post it if they do. For what it's worth, my Luxman MB3045 use DC balance and bias values of 0.75volts. They are an absolute B***** to bias. The MQ80 may be easier because I'm pretty sure it's not a cross-coupled/cross shunt design like MB3045. At any rate, hopefully I'll have an answer for you shortly. Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted October 18, 2008 Share Posted October 18, 2008 Seti, Thank you for your ebay information. I cannot find any the user as your mention "IBSlammin" on forum. Could you check again? I'll send him an email regarding this thread. Hoang, Here ya go: Call Audio Concepts in North Attelboro, MA 508-699-8819 They know their Lux tube amps. Let me know how you like your 80's. I have the MQ60's that run the 50CA10 tubes. Welcome to the Klipsch forum. tc Quote Link to comment Share on other sites More sharing options...
artto Posted October 18, 2008 Share Posted October 18, 2008 Hoang, here's another one: they sell the service & owners manuals etc for it courtesy of my friend Carroll. http://www.audiocircuit.com/index.php?c=LUX&cc=920&m=MQ-80#MQ-80 EDIT: Nevermind. I tried it myself & it appears they don't actually have any info on it "yet". I still haven't heard from my other friend so say tuned [D] Quote Link to comment Share on other sites More sharing options...
artto Posted October 19, 2008 Share Posted October 19, 2008 The bias is 0.85 volts at the cathode (test points TP2 & TP3). If there is a 10 ohm resistor across the test points (similiar to MB3045) then this translates to 85ma. The test points are usually labled on the bottom of the circuit board under the chassis. It sounds to me like there is only a bias adjustment on the MQ80 (unlike MB3045). But for what it's worth, the bias and DC balance values are the same on the MB3045. BTW, have you seen any Luxman M300? I might be interested in buying some. Quote Link to comment Share on other sites More sharing options...
artto Posted October 19, 2008 Share Posted October 19, 2008 My friend also emailed me a schematic but its for the KMQ80 which is the Japanese version which uses 100vac mains. I can email it to you if you like. Quote Link to comment Share on other sites More sharing options...
minasu Posted October 19, 2008 Author Share Posted October 19, 2008 Artto, As your advice but it seems that bias 0.85mv overload for MQ80, the 6336s very hot --> I go down to 0.7mv, Now sound is better but not best. KMQ80 is the same MQ80, could you mail KMQ80's manual to me? Highly appreciated Your assistance. Regards, Hoang Quote Link to comment Share on other sites More sharing options...
artto Posted October 20, 2008 Share Posted October 20, 2008 I can't seem to email an attachment through the Forum email so I'll post it here. If you need better quality email me with your regular email address and I'll send it to you. I'm surprised that you feel the MQ80 sounds better with the tubes running cooler. On the MB3045 my experience has been the opposite. As a matter of fact, most people seem to have trouble getting the bias/DC balance values to 0.75v on MB3045 and must use 0.5v to 0.7v at because that's all they can get out of it. I have never had any problem attaining 0.75v and can easily push it to 1v or more. Maybe its just because my valves are in better shape ~ I don't know. I think I read somewhere, maybe in a DIY article that 6336 ran hot. The schematic definitely shows 0.85v for the bias so unless you can smell the transformer windings and more than normal phenol smell I wouldn't worry about using 0.85v. Also, I might add that my MB3045 need 60-65 minutes to warm up until they sound "right". At about 63 minutes something happens, the sound "locks in" and becomes much more focused and transparent. You can even see it on a volt/ohm meter at the test points. The voltage all of sudden stabilizes instead of teeter-tawing back and forth between the bias and DC balance. All three of mine have always done this since day one so its not due to aging. For what its worth, my friend said the MQ80 is supposedly the least colored of the Luxman valve amps. He also has a modification for MB3045 to use EL509, which he is quite sure is what the 8045G output valve was based on. One guy who has done the mod says it has even better tone. Quote Link to comment Share on other sites More sharing options...
minasu Posted October 20, 2008 Author Share Posted October 20, 2008 Artto, Thank you for you good confirmation about 0.85v, I have tried again with this level the shound is more tight and more attractive, now I don't afraid about heat of 6336 becasue it is normal Pls kindlysend attachment to me. Again thank you all of you about MQ-80 bias adjustment. Regards, Hoang Quote Link to comment Share on other sites More sharing options...
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