• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

1070 unbalanced volume

Richs_Trains

Richs_Trains

Well-Known Member
Hey All,

I have a 1070 that I have recapped the power amp, pre-amp/tone and power supply. I am able to adjust the DC offset and bias to spec of 0mv and 10mv and they hold steady for both channels. My problem is the left channel is noticeably louder a brighter than the right. I have listened with headphones and the problem is the same. I have connected a tuner (115) with a output control direct to the main amp and I get even sound from both channels. I had thought it might be one of the transistors on the pre-amp/tone board, but all those test good using the procedure on AK for a DMM. If all the transistors test OK using a DMM, does that mean they are in spec also? Is there a way to tell if the left is bad (too loud) or the right is the bad one (too soft). Can I measure the signal going into the pre/tone board using a DMM and compare left and right readings and also on the output side? Any ideas on my next step? Any help would be much appreciated.

1070_after_1.jpg

I would like to try reading at the 3 pins in the middle of the board (front being input and back output), assuming that the center is ground and left is left and right is right. Can I do this and both not do any damage and get a comparative reading? Thanks Rich
 
Register to hide this ad
Well, while waiting for some direction from the group, I decided to try some things.... I reversed the L/R on the input side of the tone board and the problem moved, I reversed the L/R on the output side of the tone board and the problem moved. I am guessing that this points to the tone/pre board being good. I decided to spray down the switches and selectors again and see if I'm just missing some dirt, no luck, but I did notice something strange.

The loudness control only seems to function on the quiet right channel, the louder, left channel. does not change when the loudness is pushed. If I use the reverse selector, the channels are slightly more even, but the loudness still is on the right channel only. Any thoughts???? Thanks Rich
 
Last edited:
So after leaving it sit overnight and letting the de-oxit soak, the loudness works on both channels and they are closer to being even. More and more I think it is a dirt problem, but I have de-oxit on this on pretty good. Going to let it sit so more and then work the switches again. Thanks Rich
 
This could be it. I've had a few that didn't correct on the first try with Deoxit, but after another application or two, the problems finally went away. Hope this does it for you!
 
Sometimes one or two cleanings isnt enough. Im working on a 2230 right now that Ive had to clean the tone control pots 5 times before i started getting clean fluid out of.

I would think the problem may be a switch being dirty still. They can never be too clean!
 
You have to be careful when cleaning controls, you can wash the damping grease out and then they lose that 'silky' feel. I see this all the time from over zealous cleaning efforts.

Tom
 
Thanks Tom, I try to stay away from sliders when possible and have always been a little 'cheap' with the spray. Sometimes it is hard to beleive just how dirty these things are are. Rich
 
catrafter said:
You have to be careful when cleaning controls, you can wash the damping grease out and then they lose that 'silky' feel. I see this all the time from over zealous cleaning efforts.

Tom
Click to expand...
Will going back with Faderlube F5 help that? Do you recommend it if you have had to clean quite a bit?
 
I am not really sure about the different kinds of caig products, except what I have read. It seems all of the D-5 series contains solvents and lube, the D-100 series is just lube and no solvents, and the D-N5 series is a non drip version of the D-5. Red (D) for regular pots, Green (F) plastic/faders and Gold (G) for metal contacts. I try to use the correct solvent for the application and the add a drop or two of the D-100 series, they sell it in a needle valve dispenser. I stay away from faders only because cleaning them does affect their 'silky feel' and usually just put a dab of F-100. Rich
 
When I use faderlube when cleaning pots I always tip the pot back with the shaft up so the liquid does not wash the grease out.
You keep that "silky"feel.

Bob
 
You must log in or register to reply here.
Back
Top Bottom