Can Anyone Tell Me What This Pot Does in AN Soro?

[juancho]

See attached photo. There is a pot in the bottom right corner that doesn't appear in the circuit diagram. Can anyone tell me what its function is?It's on the input board

 

[kevinkr]

Can't see the pot, and probably like most members here have no clue what an AN Soro is.. (And not going to google it.)

How about a description, better picture and a schematic?

 

[miklos]

Audio Note Soro SE an expensive Integrated Amplifier with 6L6 output tubes.
In the picture must be the ECC82 driver tube with 15k plate resistors and the 470nF coupling caps to the 6L6 G1. No clue about the pot, maybe a fuse?

 

[juancho]

Done somewhat in haste so here's some more details:

1. AN Soro is indeed the Audio Note Soro amp
2. The picture shows the input board and the pot is there in the bottom right hand corner
3. The amp is not mine and I am diagnosing at distance for a friend. If I could see the amp I could work it out in seconds....
4. No pot is shown in any Audio note schematics
5. So I'm really looking for someone with Soro experience to be able to tell me
Thanks

 

[Mooly]

It looks a big pot. Could it be for hum bucking (or whatever you guys call it )

 

[juancho]

Its on the input board........

 

[Mooly]

And its got to be placed somewhere

(I don't know, I would have to see how the pot is connected. I assume you have just the one pot on that board. Valve heater is common to both, so hum bucking was my best guess)

 

[zelgall]

Oddly enough, it doesn't appear on the other photos of the Soro or the Oto, which uses the same board.

http://audiofederation.com/wp-conte...591-audio-note-soro-phono-se-open-chassis.jpg

 

[miklos]

And its got to be placed somewhere

(I don't know, I would have to see how the pot is connected. I assume you have just the one pot on that board. Valve heater is common to both, so hum bucking was my best guess)

I don't see any hole on it to turn the pot.
Are the output tubes working in parallel ?

 

[miklos]

Done somewhat in haste so here's some more details:

1. AN Soro is indeed the Audio Note Soro amp
2. The picture shows the input board and the pot is there in the bottom right hand corner
3. The amp is not mine and I am diagnosing at distance for a friend. If I could see the amp I could work it out in seconds....
4. No pot is shown in any Audio note schematics
5. So I'm really looking for someone with Soro experience to be able to tell me
Thanks

Can the schematics be posted here?

 

[Mooly]

I think I can see a slot although it looks a sealed and captive component. The pot reminded me a little of the old wirewound types used for convergence adjustment on old CRT TV's.

 

[Mooly]

Can the schematics be posted here?

I suspect that would be an infringement of copyright as it seems a fairly recent (current ?) production unit. If someone has a diagram then they should be able to describe what the pot does, or where about in the circuit it connects.

 

[JonSnell Electronic]

I remember those pre sets from years ago. They are carbon composition 1W and have a 270 deg rotation. I think, if AC heaters, it is the centre adjust for hum. An afterthought maybe. Following the connections will prove it.

 

[juancho]

4. No pot is shown in any Audio note schematics
5. So I'm really looking for someone with Soro experience to be able to tell me
Thanks

 

[kevin gilmore]

possibly in series with the filament to lower the voltage a bit.

 

[juancho]

possibly in series with the filament to lower the voltage a bit.

Regulated heater psu I'm afraid

 

[zelgall]

If you look at the photo link of the Soro in post #8 you will find there is no pot on that board and that since the Oto uses the same input board, also with no pot, it may be special. Maybe if you can get your associate to take a decent photo of the board and the area of the pot you could get a decent answer. It could be a different revision than most and perhaps someone, even you, living in the UK, could just phone AN and ask.
All of the guesses in the world won't get you any closer to an answer.

 

[juancho]

If you look at the photo link of the Soro in post #8 you will find there is no pot on that board and that since the Oto uses the same input board, also with no pot, it may be special. Maybe if you can get your associate to take a decent photo of the board and the area of the pot you could get a decent answer. It could be a different revision than most and perhaps someone, even you, living in the UK, could just phone AN and ask.
All of the guesses in the world won't get you any closer to an answer.

It is of course obvious that there is no pot in the photo in Post 8-noone is questioning that. I also know that other Otos were built with the pot. Not surprisingly I did suggest the owner contact Audio Note who haven't replied either to e mail or phone calls.

As I clearly and politely stated in Post 4 I'm looking for someone with direct experience of the Oto or Soro with this set up who can tell us what its function is, not wild guesses. It's prudent to establish precise function before the not so experienced owner replaces it as it's causing intermittent noise.

 

[juancho]

We received a reply from Audio Note today. The pot was used for balancing the ht voltage between the channels on early OTOs (and probably Soros?). Later models just used the two 20k resistors shown on the schematics that are around as it was largely redundant.

So that explains exactly why when the pot gets noisy it manifests as an intermittent crackle on both channels