Minor Channel Imbalance at low volumes

ashneel · 4590

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Offline ashneel

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on: January 18, 2013, 04:06:09 AM
At very low volumes, I get the impression that the right side of the HD650s sound a bit louder. My voltage and resistance checks are also all ok.
I've tested directly through my ipod, and it isn't headphone defect. I've also swapped the L/R channels, but it is the same.
 
Apparently analog potentiometers controlling volume, exhibit some degree of channel imbalance, at low volumes? Is that true. Can someone plz help



Offline Grainger49

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Reply #1 on: January 18, 2013, 04:19:47 AM
This is typical with a volume control that is low cost.  The tracking, i.e. matching from channel to channel, is poor when you don't spend upward of $30 for a pot.  There are quite a number of posts of Bottleheads who have improved upon the tracking and sound with a more expensive part.  Do a search on either volume control or pot in the Crack folder. 



Offline ashneel

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Reply #2 on: January 18, 2013, 04:27:36 AM
Thanks for the help and advice..I just wanted to know if that was normal, and not smthg I messed up during construction. It only occurs at very low volumes, not "normal" listening levels, so I'll be able to live with it  :P
Amazing how you get instant help on the Bottlehead Forum..Cheerz



Offline Paul Birkeland

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Reply #3 on: January 18, 2013, 08:42:12 AM
You can also remove the red and white wires that go form the RCA jacks to the pot and solder in a pair of 100K resistors in line with each wire to attenuate the input to the pot.

This will mitigate some of the poor tracking at lower levels.


Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Zimmer64

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Reply #4 on: January 18, 2013, 10:46:06 AM
Had a similar problem with my Quickie at the time. Once I had put in an Alps pot (moderate upgrade cost), the problem went away.

Best

Mike

Nelson Pass F5 Turbo V2, Quickie (mod), S.E.X. 2.1, Tubes4hifi SP14, Dynaco VTA ST 70, Tubelab SSE, Vroemen Diva Superiore ER4, Jordan JX92S VTL, 47 labs 0647 CD, Aqvox DAC, Rowen Absolute pre / psu / power amps, BG Neo3 / Betsy / Eminence A15 open baffles


Offline ashneel

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Reply #5 on: January 18, 2013, 10:40:54 PM
It is not actually bothering me..though can you link me to a decent and affordable pot? I'm sorry, I'm new to all this. Ebay would be quite helpful since I'm in Mauritius..



Offline Zimmer64

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Reply #6 on: January 19, 2013, 08:39:34 AM
I bought an Alps RK27: http://www.alps.com/WebObjects/catalog.woa/E/HTML/Potentiometer/RotaryPotentiometers/RK271/RK27112A00AK.html

Here is a place in the UK: http://www.hificollective.co.uk/, but you get the Alps probably also on the bay.

Mike

Nelson Pass F5 Turbo V2, Quickie (mod), S.E.X. 2.1, Tubes4hifi SP14, Dynaco VTA ST 70, Tubelab SSE, Vroemen Diva Superiore ER4, Jordan JX92S VTL, 47 labs 0647 CD, Aqvox DAC, Rowen Absolute pre / psu / power amps, BG Neo3 / Betsy / Eminence A15 open baffles


Offline ashneel

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Reply #7 on: January 19, 2013, 09:39:40 AM
Thanks mate, UK shipping to Mauritius is quite fast. Will these be ok?
http://www.hificollective.co.uk/catalog/-c-61_96_98.html?sort=6a&page=1
They're about 12pounds



Offline Zimmer64

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Reply #8 on: January 19, 2013, 09:43:53 PM
Yes, take the 100K Ohm one.

Best

Mike

Nelson Pass F5 Turbo V2, Quickie (mod), S.E.X. 2.1, Tubes4hifi SP14, Dynaco VTA ST 70, Tubelab SSE, Vroemen Diva Superiore ER4, Jordan JX92S VTL, 47 labs 0647 CD, Aqvox DAC, Rowen Absolute pre / psu / power amps, BG Neo3 / Betsy / Eminence A15 open baffles


Offline earwaxxer

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Reply #9 on: January 20, 2013, 04:54:14 AM
Yep - cant go wrong with the Alps....

Eric
Emotiva XPA-2, Magnepan MMG (mod), Quickie (mod), JRiver, Wyrd4sound uLink, Schiit Gungnir, JPS Digital power cord, MIT power cord, JPS Labs ultraconductor wire throughout, HSU sub. powered by Crown.


Offline andrewuk

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Reply #10 on: January 20, 2013, 05:05:23 AM
Its a funny old thing about volume controls or pots discussions rage, all over the galaxy, about the virtue of Alps over that make over some other one and although I have tried quite a lot the only thing I am sure about is that an Alps never has the problem outlined as the start of this thread. And, imo, that is the only virtue. I have never reliably heard a make of pot sound better than any other cheapie, or indeed the sort of 24 stage switches that have a couple of dozen surface mount resistors or indeed Dale's the like of which are lovely and cheap on eBay from Hongkers. Transformer based volume controls are in another league entirely but not without their problems i.e. mismatched impedance.