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Fixing Volume POT on a Used Preamp and Why I had to do it.

Rega

KiranPS

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I wanted to share my experience on buying a used preamp , how it was damaged, and how I did some more damage to it and How finally fixing it, actually worked out in my favor. This is so that someone else who might have bricked an expensive audio gear can actually salvage it pretty easily.

I got a used Musical Fidelity A5 Preamp (1 year old According to the seller) for 50k,
during the sale the seller sent me couple a pictures of the preamp and right away
I noticed a 1 cm dent in the Solid aluminum handle.

I guessed this could happen only if someone had
dropped the preamp on its handle or if someone had filed it off. When I asked the
seller he told me that the amp got dinged when the amp was being pulled out of the
Rack and he also assured me that everything else was fine and the Unit was not opened.

Here is the email I got fom the Seller
The Pre amp was not dropped. The pre is working fine and we have not experienced any problems in the Volume pot or other any other parts in the pre amplifier. Rest Assured , all the buttons in the front panels work flawless and the sounds the way it should.

I believed the seller and ordered the unit and it arrived the next day (Did not have original packing).
Right away I noticed that the amp either had been used for much longer than a year
or the owner did not take very good care. Second I noticed when pulling the amp out of the
cardboard box that something was rattling inside the amp. Third I noticed that the
volume control knob was loose and was shaking as if the POT screw was loose. Now I knew
that someone had infact opened the unit.

This is when I realized Buyers Beware !!!! . No matter what the seller said, I should have checked the Amp personally visually before buying. I would never have paid 50k for a used bangned up Amp with stuff rattling inside the cabinet.

Now I know that if a seller says there is very little damage, You should assume that the damage is a lot worse than what he is revealing. If the seller says there is a little crack, assume that the whole thing is broken in two :) , do a visual inspection and then buy it.

To the sellers credit, he did offer to take the Unit back when I told him about the state of the unit. Since I had opened the Unit to see what was rattling and did some damage of my own, I could not return the unit to the seller now in right conscience.



I wanted to see what was rattling inside the cabinet because I did not want to switch on the unit with some loose screws shorting some power circuit.

I had some reservations about opening an audiophile grade preamp , and I was wary of letting out the Expensive Pixe Dust and Magic Spells the Audiophile druids have locked inside the cabinet during the assembly. I assume that is why these devices cost a fortune when you buy them new.

Well I decided to open it, When I opened the unit up I found that two screws that held the main PCB were missing, these had come loose and were rolling about in the cabinet. All the other screws on the board was also loose so I tightened all of them. I wanted to now fix the loose POT , this is where a I should have had a little patience.
I assumed that the volume knob was just pressed on to the POT shaft so I tried to pull it out, so that I could fasten the Pot screw.
I did not realize that the Volume Knob had its own screw that should have been first loosened with an alan Key. When I used some force and yanked the Knob, the whole shaft from the Pot came out along with the Knob destroying it completely.

Now I thought, well Ive lost Rs 50k. After a brief self loathing , I decided to look if I could get a replacement part. It was an ALPS 50k Log Pot, I looked online and found the part both in RSIndia and on Ebay from a german seller. Just to be safe I ordered from both the places and got the EBay unit first. I de-soldered and removed the Old POT and Soldered the new Pot. The new POT was bigger but the Pot Pins matched perfectly, The mounting pins did not match so I just bent them away. Since the POT is support by the body with the screw it did not matter that much.

With the new Pot in place I found that the volume control was a lot more smoother and then a little research i found out that the POT I got is infact called ALPS Blue Velvet POT that is preferred in audiophile gear. The one that was already in the unit was a standard motorized pot. So things did work out well.

Now I have a perfectly working Musical Fidelity A5 Preamp with Upgraded Audiophile POT for volume control. I'd have to say that internet , ebay etc have enabled us to locate pretty hard to find parts easily.

The First Image is the Old Pot with the Shaft pulled out.
The Second Image is the Blue Velvet Pot.
The Third is the Ding on the amp handle.
 

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koushik

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This is very sad to know. Anyway is it working perfectly now?
Alps blue velvet is one of the finest pot, if not the finest. It should work as a positive mod to your preamp. A boon in disguise, as they say.
 

Thad E Ginathom

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Very unhappy to hear of your experience with this seller. How can anyone do this, and with a high-price item too? :mad:

Since I had opened the Unit to see what was rattling and did some damage of my own, I could not return the unit to the seller now in right conscience.
Proving your ethics to be much superior to those of the seller.

After a brief self loathing

:lol: :clapping:

Great writing does not have to consist of many words, and you've hit it there! Just perfect.

I fear my "self loathing" might, in the circumstances, have been much longer than yours, and I don't think I'd have got together to actually repair the situation.
Now I have a perfectly working Musical Fidelity A5 Preamp with Upgraded Audiophile POT for volume control.
Brilliant. Well done, and thank you very much for sharing.

How does it sound?
 
Last edited:

reignofchaos

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Is this the same one that coolvikas was selling? I guess forum members should be wary of him then.
 

KiranPS

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Is this the same one that coolvikas was selling? I guess forum members should be wary of him then.

I don't think so, I got it from Coimbatore via a link from olx. To be fair the seller did offer to take it back.
 

KiranPS

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This is very sad to know. Anyway is it working perfectly now?
Alps blue velvet is one of the finest pot, if not the finest. It should work as a positive mod to your preamp. A boon in disguise, as they say.

It's working perfectly, but it a tad bit bright when paired with parasound amp and epos speakers. I read that MF amps are usually bright , I guess they work well when paired with Warmer speakers like warfdale etc.
 

koushik

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I am not sure if Wharfedale is warm. In my opinion, wharfy too is bright sounding. Try B&W or Quad. For some reason I am not remembering any warm sounding speakers than there two.
BTW what is your range of budget?
 

tirthankar

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Good job there. Alps blue velvet is the second best pot Alps makes, right after black beauty. It's tracking and channel balance is quite good for its price.

Have you checked for signal bleeding in the pot by turning down the volume to the lowest point and then putting your ears right next to the speaker?

I would suggest you wait around 25-30 hours for the new pot to settle in. Also, you should keep changing the volume, at least over the usable range. Or else there may be deposition in the pot in the long term which messes up tracking.
 

KiranPS

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For some reason I am not remembering any warm sounding speakers than there two.
BTW what is your range of budget?

I am saving up so that I can get a sonus faber in the 3-4 L range. SF sounded great when I auditioned them.
I'd probably change the preamp if it does not sound good on the SF.
 

KiranPS

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Have you checked for signal bleeding in the pot by turning down the volume to the lowest point and then putting your ears right next to the speaker?

I do notice signal bleeding , I am able to hear faint music playing even when the volume control is turned all the way down. More worrying part was that I can also hear a very faint hum even if the pre amp is not connected and just the parasound amp is on. Is this normal ? . Is the parasound picking up ambient noise ?
 

koushik

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More worrying part was that I can also hear a very faint hum even if the pre amp is not connected and just the parasound amp is on. Is this normal ? . Is the parasound picking up ambient noise ?

Is your Amp used one? If that then do check the Power Caps and also check the ground of the AMP as well as your house supply. Improper grounding can even destroy your speakers
 

Audio_Freek

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Kiran PS,

Hats off for your gentleness to say "Since I had opened the Unit to see what was rattling and did some damage of my own, I could not return the unit to the seller now in right conscience"

I haven't come across much gentlemen like you in life,50,000 INR is a huge amount (even though if you earn 1 Crore per annual) .Great that you are very patience even after knowing that the seller has tried to cheat you.

And wat to say about your attitude,amazing one, just you have drafted a thread with your experience to help others.

"GOD Bless"

If i was in your position, would have tracked the mobile number and would have damaged his face(Sorry for being violent:), if he refuse to repay the money.There is nothing wrong on your side as din got the stuff for 10 or 20% cost,U just paid the actual cost.

This is cheating, you being genuine buyer had given money and he has cheated you purposely.


Atleast you got some force to fix the issue and somehow find the justice for the money you spend, thats makes bit happier.


My personal advice, Dont buy used amps or speakers until you investigate on your own eye and make decision.Else move on the trusted source like "For sale" in our forum ,Ebay etc,Its really difficult to trust even a person who i very close to us,

Every (IN)HUMAN is running towards money, and there is no guarantee that they will not stamp you.

Be-aware,and awake.

Finally thanks for a neat description of your experience, hope the fm's who read this would learn something, if not before:)
 

Thad E Ginathom

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50,000 is actually more than I have ever spent on a new hifi item. Not more than the RRP before discount, but more than I spent. Kiran PS is both generous in spirit to the seller as well as resourceful in repairing the amp. Last, but not least, he writes a great story. A post to remember :)
 

KiranPS

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Thanks for the support guys.
I was assuming all along that I was the only one to blame for this, well I guess the seller is also to blame for sending a banged up unit in the first place. I don't make anywhere near , to make 50k trivial for me. I buy audio gear by saving up every month, since its more of a passion for me than a luxury I can afford. I was beating myself up for a very expensive mistake.

I feel much better now. Thanks once again.
 

Thad E Ginathom

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I figured, from that self-loathing, that it was not a trivial amount. I've felt the same way about smaller accidents: if I add a few together I can imagine what it was like for you. Fifty-thousands don't grow on trees, even in the gardens of our wealthier members :eek:

Been through those moments when, thinking I'm being really careful, I open a case --- and parts fall over the place. Finally realised that I could not reassemble a clock when I was about twelve, but still made many other mistakes since.
 

KiranPS

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Is your Amp used one? If that then do check the Power Caps and also check the ground of the AMP as well as your house supply. Improper grounding can even destroy your speakers

Koushik,
Its a new Amp, I changed the extension chord and the noise has come down a lot. I guess I need to run a separate earth wire just for the HiFi Circuit.
 

Audio_Freek

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Thanks for the support guys.
I was assuming all along that I was the only one to blame for this, well I guess the seller is also to blame for sending a banged up unit in the first place. I don't make anywhere near , to make 50k trivial for me. I buy audio gear by saving up every month, since its more of a passion for me than a luxury I can afford. I was beating myself up for a very expensive mistake.

I feel much better now. Thanks once again.

I too sail in same boat, I use to save monthly and get some stuff once in 6 months, not a part of upgradation just as collection and will sell the old-set-up when i feel out of interest.

Only one thing i can say here, Mistakes are common even in GOD, else he would have not created CULPRITS and FRAUDS in society where noble and gentle people live.

So Learn from Mistake is the best way to compensate the mistake done, I cant agree that you are committed a mistake- so dont feel guilty

IF TRUSTING THE FELLOW MEN is a mistake then,Life itself a mistake

Be cautious on getting things, i Feel bit sorry that am From Coimbatore, really feel for my people, it was the land for good hearts once ,now everything getting spoiled coz of money:(


Await for some BIIIIIIIIIIIIIIIIIG surprise gift from God, he never disappoint good hearts:)
 

tirthankar

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Koushik,
Its a new Amp, I changed the extension chord and the noise has come down a lot.

Extension cords are a bad idea, especially for quality electronics.

I guess I need to run a separate earth wire just for the HiFi Circuit.
Why only earth wire? I say go for a dedicated power line including earth for your Hi-fi equipment, straight from the meter box. Any good quality thick gauge wire will do. I use 4 sq mm finolex for live & neutral, and 2.5 sq mm for earth.
If not possible from meter box, at least from the first distribution box inside your house.
Clean power is worth it.
 

Dietmar

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Hello Kiran,
I have a Musical Fidelity Amplifier A5. I have seen that you have experience with the volume control. My Amplifier ist making terrible noise when I turn the volume control knob. I need to exchange the volume control unit. It is coupled with a motor to control volume by the remote control. Could you please tell me wehre you got a spare part and what the part number is. Do you have a Tip how to exchange it? Is there something to consider during repair?
Thanks für your feedback end best regards,
Dietmar
 
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