• 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

Loss of volume do I have an Amp problem? Help with diagnosis

B

bobspets

Well-Known Member
When listening to LPs via receiver turntable setup I am having to turn the volume setting higher and higher to receive the same volume level I previously enjoyed. As I do this I see the level meters are reaching close to peak output. The problem does not occur in the FM section. Your thoughts?

Thanks in advance
Bob
 
Register to hide this ad
Sounds like your phono section make have a problem. Is the AUX input OK as well? What model is the amplifier? Are there volume pots for the inputs? Have you tried another cartridge?
 
Stylus maybe not mounted properly in the cartridge ? Or maybe the magnets are losng their strength ?

It would be strange fro a fault in the amp to affect both channels equally. It happens but not often.
 
drknstrmyknight said:
Sounds like your phono section make have a problem. Is the AUX input OK as well? What model is the amplifier? Are there volume pots for the inputs? Have you tried another cartridge?
Click to expand...

Thanks for the reply. Haven't tried the Aux. No, no seperate volume for inputs.
Haven't tried a new cartridge, does a cartridge "loose volume" over time?
 
JURB said:
Stylus maybe not mounted properly in the cartridge ? Or maybe the magnets are losng their strength ?

It would be strange fro a fault in the amp to affect both channels equally. It happens but not often.
Click to expand...

Thanks for the reply. Is "loss of volume" typical for cartridges with a fair amount of use?
 
drknstrmyknight said:
Sounds like your phono section make have a problem. Is the AUX input OK as well? What model is the amplifier? Are there volume pots for the inputs? Have you tried another cartridge?
Click to expand...

Thanks for the reply. Haven't tried the Aux. No, no seperate volume for inputs.
Haven't tried a new cartridge, does a cartridge "lose volume" over time?
The receiver is a Scott 390
 
I've never noticed a cartridge just start losing output over time. However, loss of strength in the magnet(s) could do it, so I mentioned it. Pretty odd for something like that to happen to the amp without some sort of audible distortion.
 
JURB said:
I've never noticed a cartridge just start losing output over time. However, loss of strength in the magnet(s) could do it, so I mentioned it. Pretty odd for something like that to happen to the amp without some sort of audible distortion.
Click to expand...

Yes, it's odd I don't notice any distortion
 
i take it yours is the 390r model ?
just looked at schematic and level meters are wired just before main amp inputs .. so this is rather baffling . in theory the problem cant happen unless i am missing something such as frequency coming from turntable or riaa amp doing weird stuff to main amp .
what i am saying is whatever the level meters are showing should be whatever the main amp is seeing .. will be just same for tuner or any other input ..
its looks a pretty busy bit of circuitry in that unit by the way
 
Last edited:
you could try a couple or 3 things ..
switch 390 off and let record keep playing for 3 or 4 tracks then turn 390 back on and see if vol returns ..
do opposite and turn TT of for a while with amp on .
turn it all off and back on in a few minutes ..
try one channel at a time .. like just right TT input then left .. don't think this will yield much but you never know .
try work switches whilst vol dropped and see if it comes back ...
 
petehall347 said:
you could try a couple or 3 things ..
switch 390 off and let record keep playing for 3 or 4 tracks then turn 390 back on and see if vol returns ..
do opposite and turn TT of for a while with amp on .
turn it all off and back on in a few minutes ..
try one channel at a time .. like just right TT input then left .. don't think this will yield much but you never know .
try work switches whilst vol dropped and see if it comes back ...[/QUO

Thanks, I gave those suggestions a try, no dice. Just to clarify the TT volume is constant just lower than previous and lower than meters would appear to indicate. As I listen now seems TT has less "punch" as well not sure how to quantify that other than describing it as subdued though that may be an effect of lower volume.

I was looking at the cartridge the other day and thought the stylus was significantly worn though I hadn't noticed any difference in sound up to this time. I think I will switch it out and compare. I have an identical replacement stylus. I shouldn't need to adjust anything when replacing the stylus correct?
Click to expand...
 
Update ripping hair out! new problem HELP So I took the Amp. to my local audio shop and explained the problem and had them service the unit. I talked to the Tech. he said he ran the unit through all inputs and speaker selections and he could find absolutely no abnormalities, but he cleaned the switches and I took it home. I hooked it back into the same system as before and until today it ran flawlessly.

New problem I played several LPs this AM all going swimmingly until the left channel suddenly drops out right sounds great left dead. When I switch the unit on for a few seconds both meters are normal, this is very brief just as the unit is switched on. As a new event that left channel is lost in FM as well.
Let me digress a little, before I put the 390 into service a few years ago I had the unit professionally serviced power switch was replaced and all switches cleaned and tested.
I took it home and it ran flawlessly until the original problem I mentioned in this thread began.
 
Bobspets, can you show how you've wired up the turntable to the receiver? Something is amiss in how you've set the system up if the tech was able to get it running correctly.

Other possibility is if it has a speaker protection relay, the left channel relay contacts could be oxidized leading to decreased or intermittent sound. We have heard of wonky power switches also doing odd things.
 
Hey Mech986 good to see you, I really appreciate the reply.Looks like you changed your handle, but I recognize your cat. Is he still with us?

Not able to take any pics at the moment, but I'll try to explain the setup. So I have the 390 hooked to Dual 1246 via the standard rca cable directly to the phono input then I have my DCM 500s (LOVE E'm) hooked to the 390 via standard speaker wire/cable though I am using the second set of speaker inputs as a matter of fact I'm going to switch to another speaker input now and see if that makes any difference.
 
I do clean the stylus regularly, but I have some doubt that cartridge itself might have an issue? I hate these damn intermittent problems makes it hard to nail down.
 
I just switched speaker inputs no change. I did forget to mention one thing, when I switch the unit on I can hear some static in the right speaker for a few seconds. I'm gonna switch speakers see what happens.
 
Sounds like a faulty protection relay possibly. Does the static go away as the volume is turned up?
 
Switched speakers and wires. I can get right or left if I switch wiring order still can't get both simultaneously
 
It doesn't last long enough for me to adjust volume That was supposed to quote faber12s comment
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom