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My Luxman LX-33 integrated amp uses 11 tubes, 4 x EL34, 2 x 12AU7, 1 x 6AQ8, 4 x 12AX7I have put in new tubes which I like a lot but for the bias, ac, and dc voltage adjustments I have set them all on what appear to be default or middle position (?)
I do not have a manual for this amp as it is only available in Japanese.
It has a rather slight hiss in the right channel. It is not a big problem but it is not noticable in the left channel. I would like to know if this could be related to these adjustments.Also is it safe to use the amp without fine-tuning these adjustments? How will this affect tube life and performance?
Follow Ups:
To do this as is suggested by the manufacturer you will need to get the required bias figures from their instructions which are very likely contained in the owner's manual or, failing that, the service manual.
A quick web search didn't turn up any LX-33 manuals currently for sale and an AA search turned up a few references but no technical numbers.
I did however find one post by another LX-33 owner on the K&K forum . Perhaps you could email him to see if he has the biasing instructions?
His post (and linked email ) is linked below
Oh yeah, if the above doesn't yield results . . . While I was searching I ran across reference to a Yahoo Luxman Group. You might try over there as well.
hope this helps
Setting the controls to "middle" is not correct.You risk damage to your amp using it this way.
I doubt very much that the adjustments you have made would produce the hiss you hear. More likely would be the cleanliness of the tube pins/sockets, switches and/or circuit layout. The most important consideration will be the bias adjustment. Please measure the DC voltage from each of the EL 34 output tubes at pin 8 to ground and report back. If pin 8 is grounded, then purchase a half dozen 10 ohm/ 1/2watt resistors from Radio Shack, match 4 as closely as possible and install them between pin 8 and ground for all four output tubes. Then measure the DC voltage between pin 8 and ground and report back.
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