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Luxman R-117 distortion in the mid and upper range.

dbtommy

dbtommy

New Member
I have a newly purchased (used) Luxman R-117 that I've noticed distortion in the mid and upper ranges and those ranges seem to be recessed (filtered into the background of the overall soundstage).
Any thoughts would be greatly appreciated.
Also any suggested techs that are good with this type of problem /trouble shooting, located in the Worcester /Boston /Nashua triangle? Would be appreciated as well.
Would like to get this checked out.
Thanks in advance!
 
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dbtommy said:
Any thoughts would be greatly appreciated.
Click to expand...

Or not so appreciated :(:). I'm afraid my first thought is that the symptom description is too subjective for it to be of much help in diagnosis.

But to try to be helpful, I have a few suggestions that might help you, and/or a decent tech, to home in on the nature of the problem:
  • Check whether the problem occurs with different program sources.
  • Check whether the symptoms change if you fiddle with switches. Loudness, subsonic, and tone defeat would be "likely suspects".
  • If you have the means, connect the preamp output to a known good power amp and speakers, and check whether the problem still exists.
I'm hesitant to suggest this, due to a vested interest, but Holt Hill Audio in Andover has someone I'd consider a decent tech. You'd need to be patient, with lead times measured in months.

Someone will be along to suggest a re-cap. It's not impossible that it would help. It would be very costly at commercial labor rates.
 
Does this occur when using a good set of headphones ? If it does then it might be easier to locate the issue with a can of freeze spray. Looking at schematic work your way through the audio circuitry spraying each component while listening for the issue to vanish or get worse or change somewhat. You can make a few differently shaped masks to shield nearby components allowing the freeze spray to only squirt through the opening in the masks made from card stock or thin plastic. Works well for me to isolate issues like this. Would be hard to do if using speakers that are not in listening position while spraying but could be done with speakers small enough in work area or on bench top.
I am in the Worcester area if you need help.
Mr. Bill
 
I'd agree with the above that the switches, tone controls, etc. need a good cleaning. The pre-amp switching IC is also a known failure point, from what I understand.

If you have a 2nd preamp, you can try plugging into the amp in jacks directly, with the jumpers removed to isolate whether the amp section is clean sounding.
 
Speaker relays are notorious for going bad on these and can cause similar issues.
Try tapping on them if you can carefully with a wooden or plastic chop stick and see if the sound changes.
Controls on these are notorious for needing a good cleaning. This is a must and it requires taking covers off to get at them.
 
chazix said:
Or not so appreciated :(:). I'm afraid my first thought is that the symptom description is too subjective for it to be of much help in diagnosis.

But to try to be helpful, I have a few suggestions that might help you, and/or a decent tech, to home in on the nature of the problem:
  • Check whether the problem occurs with different program sources.
  • Check whether the symptoms change if you fiddle with switches. Loudness, subsonic, and tone defeat would be "likely suspects".
  • If you have the means, connect the preamp output to a known good power amp and speakers, and check whether the problem still exists.
I'm hesitant to suggest this, due to a vested interest, but Holt Hill Audio in Andover has someone I'd consider a decent tech. You'd need to be patient, with lead times measured in months.

Someone will be along to suggest a re-cap. It's not impossible that it would help. It would be very costly at commercial labor rates.
Click to expand...
Thanks Chaz,
Also possible Bias adjustment?
Am also noticing background hum when idle between tracks. Thought these were supposed to be dead quite?
 
Mr Bill said:
Does this occur when using a good set of headphones ? If it does then it might be easier to locate the issue with a can of freeze spray. Looking at schematic work your way through the audio circuitry spraying each component while listening for the issue to vanish or get worse or change somewhat. You can make a few differently shaped masks to shield nearby components allowing the freeze spray to only squirt through the opening in the masks made from card stock or thin plastic. Works well for me to isolate issues like this. Would be hard to do if using speakers that are not in listening position while spraying but could be done with speakers small enough in work area or on bench top.
I am in the Worcester area if you need help.
Mr. Bill
Click to expand...
Yes, same through my Sennheiser HD650's.
I'm certainly not a tech but have looked at the service manual and schematics. I have a rudimentary understanding of schematics and topology in general.
Given that It would take me along time to get through the operation you suggest and then still not know the 'real results' of my efforts.
I may take you up on your help offer. I am going to go through some of the other members suggestions such as remove the jumpers and isolate the pre-amp section from the amp and try another pre through the amp.
Thnx Bill
 
dbtommy said:
Yes, Good idea. I will try that. Have several.
I'm going to pull this unit out of the rack and on the bench to check this out.
Thanks
Click to expand...
I just pulled the unit and set it up with a speaker selector running three sets of speakers. They all suck in the same way as through my Cornwall IIIs.
Has to be the unit.
Was going to try that as a first step deduction anyway, but now that we have that done and gone...Thanks for the suggestion RVT.
 
Fairlane said:
Speaker relays are notorious for going bad on these and can cause similar issues.
Try tapping on them if you can carefully with a wooden or plastic chop stick and see if the sound changes.
Controls on these are notorious for needing a good cleaning. This is a must and it requires taking covers off to get at them.
Click to expand...
To Fairlane and Sam, I guess it's time to open this thing up and take a look. May take awhile as I need to order some DeOxit.
Frustrated. Maybe tapping with a big hammer would fix it? lol!!! Ehh, not really laughing...:(
 
dbtommy said:
Thanks Chaz,
Also possible Bias adjustment?
Am also noticing background hum when idle between tracks. Thought these were supposed to be dead quite?
Click to expand...
Went through the tuning process of turning treble up, bass down for tone balance. slight improvement but same poor quality and slight distortion.
Low filter off and on, nope. Same through Phones. Just tried hookup to speakers B. Same poor sound result.
 
Sounds like you have a bad component most likely a transistor or an electrolytic cap somewhere in the audio circuit. A good place to start would be to measure all the power supply voltages with a meter to make sure everything there looks to be in order. Then I would start with the freeze spray following the audio path through the various circuits.
Do you have an access to an oscilloscope and a meter and some type of source that would output an audio tones like a signal generator or a CD player with a test CD containing audio tones ? These 3 test items can be very useful for troubleshooting issues such as this. Remember I am only 20 to 30 minutes away should you need to bring it here to try finding your issue. Most good car parts stores sell freeze spray under $20 a can. Auto techs use it also for checking out suspected bad sensors in cars and trucks.
GOOD LUCK
Mr. Bill
 
dbtommy said:
I just pulled the unit and set it up with a speaker selector running three sets of speakers. They all suck in the same way as through my Cornwall IIIs.
Has to be the unit.
Was going to try that as a first step deduction anyway, but now that we have that done and gone...Thanks for the suggestion RVT.
Click to expand...

Any time.
Good luck getting it right.
 
Mr Bill said:
That was already done when he has stated that he had the same issues with the headphones.
Click to expand...

I think I risk being pedantic here, and I apologize if I am. But it is quite common for distortion problems to NOT be evident with headphones, due to their much lighter load on the power amps compared to almost any speaker.

Not saying that that is relevant in this particular case, but I think it could be.

As long as I'm kibittzing, I'd like to highlight that the symptom, as described, seems like something that is affecting both left and right channels. It's not a sure thing, but that tends to implicate problems in circuitry that is common to both channels, like power supplies.

Among the common power supplies that feed the R-117's power amps are + and - 16V supplies for the differential stages. The power amps might be able to limp along with one of those supplies being absent or low, so those are something that a tech might want to check.
 
chazix said:
I think I risk being pedantic here, and I apologize if I am. But it is quite common for distortion problems to NOT be evident with headphones, due to their much lighter load on the power amps compared to almost any speaker.

Not saying that that is relevant in this particular case, but I think it could be.

As long as I'm kibittzing, I'd like to highlight that the symptom, as described, seems like something that is affecting both left and right channels. It's not a sure thing, but that tends to implicate problems in circuitry that is common to both channels, like power supplies.

Among the common power supplies that feed the R-117's power amps are + and - 16V supplies for the differential stages. The power amps might be able to limp along with one of those supplies being absent or low, so those are something that a tech might want to check.
Click to expand...

BUT the original OP already stated the issue was in the headphones. Not sure about his amp I do not have schematic BUT at least some of the Luxman amps I have serviced take their headphone outputs off of the preamp stages. this suggests again to me that his issue could be from a bad Power supply rail or PS filtering or could be from a transistor or cap on its' way out in the preamp or tone controls section of this amp. I would be looking for issues there first. He never responded on whether or not he has any test gear including a meter. So I am guessing he is thinking this whole thing over as to what he wants to do going forwards. Sounds like he needs to find someone close by that can help r-teach him how to troubleshoot issues like this which is why I volunteered to help him since he is very local to me.
Mr. Bill
 
35 yr old unit. When my NAD 317 hit 30 years things started going, the intermittant static drove me nuts. Replacing mechanical relays in preamp solved that problem, but then more serious problem started. Did not want to pay to have it serviced, so bought a new amp Marantz Model 50 with electronic controls, switches and relays, should be trouble free for 20 years or more!
 
dbtommy said:
Went through the tuning process of turning treble up, bass down for tone balance. slight improvement but same poor quality and slight distortion.
Low filter off and on, nope. Same through Phones. Just tried hookup to speakers B. Same poor sound result.
Click to expand...
It prolly needs a good tech to check it out and replace out-of-spec parts (like main power supply caps).

Good luck! :thumbsup:
 
Mr Bill said:
That was already done when he has stated that he had the same issues with the headphones. There was no need at that point to try different speakers was there ?
Mr. Bill
Click to expand...

Except my question (post #4) came before headphones were mentioned.
 
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