Volume control for Yamaha A-520 Integrated Amp

sgautam

Active Member
Joined
Aug 23, 2012
Messages
225
Points
43
Location
Nellore
Dear friends,

I have a Yamaha A-520 integrated amp which is rated at 75 watt. SQ is extremely good and is hugely powerful. It really sings and has worked reliably for the past 2 years.

Of late the volume control is acting weird, the volume suddenly increases on its own. The problem appears after an hour or so of working and after some time it subsides.

I took it to a local techie who cleaned it but it didn't help. I didn't want to risk opening and ruining it further. I am located in a very small place in AP so kind of stuck with it. I love the amp and it is used atleast 4/6 hours daily as it runs our DTH radio setup driving two sets of speakers. So I need to get it running ASAP.

Please chip in with your advice, many thanks.
 
is it happening when you operate from remote or turning the knob with hand?
before i had semilar issue with yamaha rxv2095 and i cleaned the volume knob with deoxit and problem was gone.its a alps volume control unit.
i dont have any idea about your amp
 
If the issue is with the potentiometer, it's an easy fix. You need a dual 100k log pot with a 6mm d type shaft.

Plenty of them around. Will check around and post a link to buy them online
 
But check if this is volume control related
Does the volume change random ly?
Is there noise when you change volume?
Does the volume changing stop temporarily if you change the volume yourself?
 
in case this is indeed a volume control issue - you can either buy this

ALPHA RV16 Type Dual Potentiometer B100KX2

should be a direct replacement

21 Step High Precision Step Potentiometer A100KX2

this is a more durable design using a stepped volume control

Please note that the taper may be different ( so the nature of volume change may be different. My suggestion would be to go with the second one). A bit of jugaad using some leads may be needed to connect the second pot to the pcb. Please make sure the PCB is retained - a lot of lazy techs will take the wires and solder it directly to the pot
 
@ sgautam,

try to remove the volume knob and spray WD40 lightly....CTC (Carbon Tetra Chloride) also helps..spray the same using a syringe.
 
Dear all, sorry for my delayed response. Thanks a ton for your inputs. I will try to check it myself before going ahead further, will also try lubricating it and check.

The volume increases on its own after 30 min or so. It will be normal once I switch off/on. The amp is not remote enabled. Its a old one probably 1990 vintage.

Thanks Greenhorn for the links. I will buy the second one as advised after I am sure that the pot is at fault.
 
Yes will keep that in mind. Otherwise also I don't think I can get the correct dia. In that case will the replacement work normally or is there any issue in that.

Sent from my Redmi Note 4 using Tapatalk
 
you can get the dia using a kids ruler.
it need not be accurate - there are a few standard sizes which are few mm apart + different end types, so some margin of error is fine.
if you get the wrong type, you will not be able to fit the volume knob back - you will have to use it without a knob, or some different knob( not desirable)
 
Last edited:
Back
Top