problem with hafler dh-101 preamp

laotzu61

in the middle of november i picked up the above preamp on "the bay." the seller did explain it needed "some tlc," and that there was a problem with the bass pot sounding a bit dusty. that's not the problem.

the balance control is on the same shaft as the volume control; right behind it. what's happening is that the right channel consistantly goes in and out; there will be sound from the right speaker, then it cuts out. (rta 12b's) when i try to adjust the balsnce control, the right channel may kick in and may not; sometime it will kick in on it's own. the speaker cable connections are good on both preamp and speakers. this is driving me nuts! i did put de-oxit and lube on, and it works decent for awile, and then back to square one. any suggestions as to what is going on would be appreciated very much. also, is it possible this can hurt the right speaker? thankyou very much. :frown::frown

laotzu61

correction: i should have stated speaker connections are good between amp (onkyo m-504) and speakers, as are interconnects between amp and preamp.

Msabot1

Sounds like a defective pot,been a while since I saw a balance and vol on same post. Quick fix was that lube you hit it with,should tell ya something. That amp is far too good to risk,picked one up short time ago,glad I did. Don't blow yer output on that stage by running off that pre.

laotzu61

Msabot1 wrote: »

Sounds like a defective pot,been a while since I saw a balance and vol on same post. Quick fix was that lube you hit it with,should tell ya something. That amp is far too good to risk,picked one up short time ago,glad I did. Don't blow yer output on that stage by running off that pre.

thanks for the response. should i not run the preamp, then, until i can locate a replacement pot? if so, any idea where i can find one? i've done a search, and can't dig up anything.

laotzu61

also forgot to mention that whether or not the right channel kicks in seems to be dependent on the volume level of the source material. (cd or lp)

drumminman

laotzu61 wrote: »

also forgot to mention that whether or not the right channel kicks in seems to be dependent on the volume level of the source material. (cd or lp)

Do your 12B's have fuses in the upper Xover?

I had this exact problem years ago. One speaker would simply cut out or not come on at all. I could bring it back on by rapidly turning the the volume up most of the way, sort of flicking it, and then turning it back to a moderate level. What I discovered is that the fuse in that speaker was not seated all the way in the fuse holder. Once I pushed it all the way in that speaker worked perfectly. Hasn't been a problem since.

Make sure your fuses are fully seated in the holders. I would also replace them - sometimes they can have an issue that causes them to pass the signal intermittantly.

laotzu61

thanks, drumminman! i'll check it out. would you happen to know what type (value?) fuse i need for replacement?
thanks again

drumminman

0.75A fast blow.

laotzu61

thanks. i took off the top hats on both speakers. the fuses seem to be seated properly and don't look to be blown, but i am going to get replacements anyway. what i did notice is that on the left speakers circuit board, on the far left, there is a component (capacitor?) that has a piece of rubbery foam-type strip underneath it, and the right speaker circuit board does not; exposing what may be another cap underneath it. i hope this makes sense; don't know if this would make any difference or not. i'm also finding it impossible to find a replacement 3-gang concentric pot (volume-balance control) for the hafler. btw, i found out dianna krall is going to be in your area on tour next year, but nowhere near me. may have to go out to my sister and neice in asheville!!

laotzu61

here's an update on my problem with the dh-101. i picked up a kenwood c1, and everything works fine thru it. i then connected the hafler back up and started playing around. when i play cd's (player connected to aux) the right channel (speaker) still kicks in and out. when i play lp's and push in the phono 1 button, there's no problem, which now leads me to believe that the problem is with the aux button on the hafler. first, for those of you familier with the dh-101, can i connect the cd player to maybe phono 2 or another output; second, can i use de-oxit on the aux button for a possible better connection? thanks, and merry christmas to you all!!

doctor r

Merry Christmas. You can use any input except for ones labeled "phono". The phono inputs are designed to deal with a low voltage input from a cartridge and the CD player input voltage is probably 2 volts. The deoxit can be used on the switch and also I would look at the wires from the switch to their attachment. It is possible that you have a solder joint that is failing and when there is movement it causes just enough contact to work for a time. If after cleaning the switch contacts, you still have the problem, then touch up the solder joints that attach this switch if possible.

laotzu61

thanks. i'll check it out.

laotzu61

doctor r wrote: »

Merry Christmas. You can use any input except for ones labeled "phono". The phono inputs are designed to deal with a low voltage input from a cartridge and the CD player input voltage is probably 2 volts. The deoxit can be used on the switch and also I would look at the wires from the switch to their attachment. It is possible that you have a solder joint that is failing and when there is movement it causes just enough contact to work for a time. If after cleaning the switch contacts, you still have the problem, then touch up the solder joints that attach this switch if possible.

i just wanted to say "thankyou very much" for the info. i took the connects out of aux and put in tuner and it now works like a charm! therefore, i would assume there is in fact a problem with the aux connection, which i will get to at a later date. right now, i just want to kick back and enjoy dianna krall without the right channel kicking in and out! thanks again, and have a great holiday.

zingo

Congrats!

laotzu61

thanks, zingo. i'm a happy camper right now! have a great holiday.

doctor r

Glad you are now able to enjoy the music. Happy holidays.
Rick