Volume pot for Trio KA2000

[andyuk71]

Hey everyone.
Newbie Andy here - have already posted in the wrong place, and managed to get an illicit ebay link in too, apologies...
Anyway, hey to you all and thanks for having me
I'm attempting to restore my parents' old Trio KA2000. The 50k ohm dual volume pot requires replacing first, it's not salvageable unfortunately. I've found a seller on eBay and they look legit (he makes them apparently), but with postage, it's $111...
I've seen several restoration posts of the old Trio on here, hopjohn's being particularly notable, so it has inspired me to have a go myself. I'm a maintenance electrician and no stranger to a soldering iron, and though electronics are not my forte, I am excited to learn.
Anyway, I was hoping that some kind folk on here might be able to steer me to an alternative source for the volume pot? The specs are as follows Resistance: 50K/50K dual deck, Tap type: Audio, Loudness tap: 15K - it's four gang if that refers to the number of connections.
Looking forward to your words of encouragement!
Cheers,
Andy.

 

[goodolpg]

I've Googled KA2000 volume control quite a bit and haven't found a definitive answer.
I did see a KA2000 with the case off and the control looks like a dual pot control. First post in this thread...
https://audiokarma.org/forums/index.php?threads/the-ka-2000-restoration.845076/
Didn't read the whole thread, don't know if he had the same issue as you.

Hopefully someone will offer a suggestion. Seems like one of the parts places like Mouser would maybe have one.

 

[andyuk71]

I've Googled KA2000 volume control quite a bit and haven't found a definitive answer.
I did see a KA2000 with the case off and the control looks like a dual pot control. First post in this thread...
https://audiokarma.org/forums/index.php?threads/the-ka-2000-restoration.845076/
Didn't read the whole thread, don't know if he had the same issue as you.

Hopefully someone will offer a suggestion. Seems like one of the parts places like Mouser would maybe have one.

Thanks goodolpg. The thread you link to is hopjohn's incredible restoration. I've read every word previously, but as the unit he worked on was in general good condition, he didn't need to go near the pots. #
Thanks for doing some googling - I've done similar in the past and drawn a blank which is partly why I've joined the Audio Karma fraternity. Ultimately, there is an option available, but it's a pricey one, but hopefully someone on here, as you say, will offer a viable suggestion.
I think I'll post my ebay link on the dollars and sense thread, maybe get some traction there?
PS Yes, it's a dual concentric pot for separate left and right channel volume control, 50k ohms, with loudness taps.

 

[Tom B]

If you can show a picture, we may be able to suggest something

 

[goodolpg]

Maybe he can post a shot of the inside of his unit, if not he mentioned considering this one...

And this post shows the inside of the same unit the OP has

https://audiokarma.org/forums/index.php?threads/the-ka-2000-restoration.845076/

No idea if the user or service manual would have numbers or specs for that control.

ADDED--hifiengine has the manuals though I'm not sure if they are taking new members. If they are, it's safe, they won't spam you or sell your info.
https://www.hifiengine.com/manual_library/kenwood/ka-2000.shtml

 

[Tom B]

The auction site has many listings of Dual 50K, some with the 4th tap for loudness. They are Chinese made ALPs controls, and I have had good results from them. The only thing is that they are single shaft dual controls, and dont allow seperate L and R adjustment, but truthfully, your amp should always be equal l and r.
The cost for the many options is below $20

Check the one being sold for $100 or more. It probably has a single shaft as well.

 

[goodolpg]

I just looked at the hfe manuals
Kenwood(?) part number R04-2208
Specs 50 Ohm (T2-26) x 2

EDIT/ADDED from a similar thread, it was pointed out the control is 50K ohm.

 

[Tom B]

There is one advertised for $10.68 free shipping from China. * pins so it has a loudness tap, just not sure of tap value

RK27 Japan ALPS Logarithmic Potentiometer

1pc 8pin Potentiometer+1pc PCB, Knurled Shaft, Shaft Length 25mm, Diameter 6mm
Resistance 50KAX2/100KAX2 Selectable(get what you selected), 8pin with Loudness
RK27 Type Logarithmic Potentiometer, Dual-unit for Stereo Audio, Made in Japan

 

[Tom B]

I looked at the $90 one advertised on the auction site for the Kenwood KA-2000, and it is a single shaft as well, and wont allow for seperate L and R control. It is not an exact replacement, even though it says it is.

 

[spark1]

If you are talking about seller hifiaudio, I would advise looking elsewhere. His listing are not reliable, and if you find that the part you buy from him does not work, he will claim that you installed it incorrectly or damaged it.

He does not make parts, nor does he have them manufactured to his specs. He finds Chinese parts and resells them...in many cases at ridiculous prices.

 

[andyuk71]

If you can show a picture, we may be able to suggest something

Thanks for helping me with this, much appreciated. I'll take the advice on the seller hifiaudio with regard his reputation, and to be honest, the price alone makes it prohibitive for me.
Thanks also Tom B for your efforts - I'll do a search on the text you have pasted and have a look at it

 

[andyuk71]

There is one advertised for $10.68 free shipping from China. * pins so it has a loudness tap, just not sure of tap value

RK27 Japan ALPS Logarithmic Potentiometer

1pc 8pin Potentiometer+1pc PCB, Knurled Shaft, Shaft Length 25mm, Diameter 6mm
Resistance 50KAX2/100KAX2 Selectable(get what you selected), 8pin with Loudness
RK27 Type Logarithmic Potentiometer, Dual-unit for Stereo Audio, Made in Japan

Tom I've actually bought one of these and installed it last year. It works though it has stepped volume increments and though it's dual, it's not dual concentric so you can't split the channels. It's a solution of sorts, but...

 

[Tom B]

Thanks for helping me with this, much appreciated. I'll take the advice on the seller hifiaudio with regard his reputation, and to be honest, the price alone makes it prohibitive for me.
Thanks also Tom B for your efforts - I'll do a search on the text you have pasted and have a look at it

Andy, Whats wrong with the existing control? Can't it be cleaned using a wash spray and then Faderlube?

 

[andyuk71]

Sadly Tom I made a rookie error a couple of years ago when I first decided to have a look at this - I received the amp from my parents in working condition, but the volume control was incredibly noisy. I tried 'wiping' the pot with the amp powered off, but that didn't solve anything. Then, convinced that the pot was faulty, and critically, before it had ocurred to me that something like wash spray may fix it, I decided to go in feet first and see if I could dismantle it to clean it... - see photos below. It may still be salvageable by someone who does this for a living but I'm not experienced electrically at component level. At that stage I decided to replace it and found the same ALPS unit that you found too. I installed that and it worked but it's not dual concentric and the volume works in increments rather than analogue/linear - so for example, if the lowest volume is too loud for quiet listening, you've nowhere to go as the next detent is no volume.
I've kept my eye out for a complete amp on ebay that I thought I might be able to use for spares. But they're quite sort after and aren't cheap! Anyway, I recently took the plunge and bought a Trio KA2000A a couple of weeks ago; it's the same model but slightly later and has a silver front. It's working and I love the sound, but in reality it too is probably due some TLC. So I decided to stick with the KA 2000A and have another try at restoring my parents' KA2000. I can't wait to get cracking and have dismanlted it already, but unless I have a viable replacment for the volume control, it's a bit pointless...
I've just had my Fluke on the bottom pot that I haven't, erm, dismantled, and it seems ok. I get about 45k ohms to each side of the pot when operated each way (not explaining that very well), and measure 11.7k ohms at 'full volume' to the loudness tap. So if push came to absolute shove, I could probably re-assemble the pot and just wire both L and R channels to the bottom pot. I'd lose the ability to control both channels separately but in all honesty, I think I could live with that as a compromise.
So unless I do manage to find one, that's where I'm at!

 

[Semanon]

I see a parts unit at auction that's only a little more than the quote for the pot from the auction site. If you have some cash, buy that and have parts forever.

Short of that, consider abandoning loudness and balance until the exact right part comes up, and replacing your pot with volume-only capability.

Also, you might turn this thread into a 'fix-my-pot' thread. With the right photos the smart minds here might be able to salvage it and educate others in the future.

Good luck.

 

[andyuk71]

I see a parts unit at auction that's only a little more than the quote for the pot from the auction site. If you have some cash, buy that and have parts forever.

Short of that, consider abandoning loudness and balance until the exact right part comes up, and replacing your pot with volume-only capability.

Also, you might turn this thread into a 'fix-my-pot' thread. With the right photos the smart minds here might be able to salvage it and educate others in the future.

Good luck.

Thanks Semanon. Can't find that parts unit auction myself... A good suggestion though. Also agree with your other ideas. Particularly the 'fix my pot' thread idea. Cheers

 

[Semanon]

Search Kenwood instead of Trio. I believe they are identical, except badging.

Wait a minute...I'm thinking Andyuk might mean that you are in the UK. Figured that out all by myself, I did.

 

[Semanon]

it's four gang if that refers to the number of connections.

4-gang means four separate potentiometers in a single package controlled by a single knob. It’s sometimes referred to a 4-deck.

This is a photo of a 2-gang, 4-gang, and 6-gang pot.


This is also a 4-gang pot, with two conductive plastic wafers per section.


A 4-gang, dual concentric has two separate controls, an inner shaft and an outer sleeve/ring. This is what the Trio has for volume and balance.

EDIT: READY-FIRE-AIM! The amp has a 2-gang, dual concentric pot. Balance is obtained by separately controlling the different decks of the pot. One to self…read the schematic before making any assumptions.

 

[Semanon]

As far as ‘Fix my pot’ goes, I think you have disassembled the balance section. Even if you have totally destroyed the front section, you can recover the volume section at the rear. This would mean no balance control, but at least he unit would be running.

EDIT: see above for my bad assumption.

 

[andyuk71]

A 4-gang, dual concentric has two separate controls, an inner shaft and an outer sleeve/ring. This is what the Trio has for volume and balance.[/QUOTE]

Semanon, thanks for the education regarding the correct meaning of gangs in this context - I mistakenly thought that gangs referred to the number of terminals. I understand the concept clearly now, many thanks