SSL Alpha Channel Gain Pot problem

frabo · 12th February 2010

Hi,
two weeks ago I send back my Alpha Channel as a warranty case.
If I turn the Gain pot up to 12 o'clock and more, I got a lot of "dusty" and "crackling" sound.
Today I got a new one. And I'm very surprised, with the same problem !
I have an soundfile attached. - no Input-signal, Eq and Limiter is off, you hear only the preamp. The Output is at 12 o'clock.
- around 4 sec. I arrived the 12 o'clock zone. The loudest crackles are at 100 % gain.

Somebody with a problem like this ..?

Best regards

Frank

Matt Syson · 12th February 2010

Hi
So you get back onto the dealer and say you are still unhappy, that is what they are for.
Matt S

Jim@SSL · 12th February 2010

Is anything connected to the input? Any cables etc?

As the previous poster suggests, if this is a replacement unit under warranty you should go back to the dealer.

Sorry to hear of the problem - this is not a known issue to us.

MIKEHARRIS · 12th February 2010

i recently learned that if youre leaving the ALPHA Channel digitally...you need to put a SPDIF cable from your digital interface to the SDIF in ...so the A C will know what clock rate you are using.
Without...you will have pops & clicks

frabo · 12th February 2010

Thank you for your fast response.

Jim, I have these noise with nothing connected to the unit.
Just the output to a mixer and turn the gain pot ...

I'm in contact with the ssl support and I will bring it back to the dealer tomorrow!
But I'm very scared about exactly the same problem with the "new" unit !?
And I wonder that all of you with an Alpha Channel doesn't have any scratchy noise when you turn the gain from 50% up to the last quarter ...

Ahh, I checked it again, and I figured out that the scratchy noise is not so loud if you turn the VHD up to 50 % ...!? And it is mor or less away when VHD is 100% ....
But if VHD is 0% it is terrible !
I'll let you know how this story ends...

f.

Jim@SSL · 14th February 2010

There is no such thing as VHD at 0%. At the left it gives you 2nd order harmonic distortion, and to the right it gives you 3rd order. VHD only starts working when you drive the preamp into distortion.

Quote:

Originally Posted by frabo

Thank you for your fast response.

Jim, I have these noise with nothing connected to the unit.
Just the output to a mixer and turn the gain pot ...

I'm in contact with the ssl support and I will bring it back to the dealer tomorrow!
But I'm very scared about exactly the same problem with the "new" unit !?
And I wonder that all of you with an Alpha Channel doesn't have any scratchy noise when you turn the gain from 50% up to the last quarter ...

Ahh, I checked it again, and I figured out that the scratchy noise is not so loud if you turn the VHD up to 50 % ...!? And it is mor or less away when VHD is 100% ....
But if VHD is 0% it is terrible !
I'll let you know how this story ends...

f.

frabo · 15th February 2010

I know about that. I don't want to talk about VHD. I just want to tell you about the settings where the machine makes the worst sound.

Please, all of you with an Alpha channel, try the settings like this if you have scratchy sounds with the gain pot. Or is it just me with now two broken units?

PsilohsaiBiN · 29th April 2011

Wow, I know this thread has been dead for about two months but I have a similar problem. My Alpha Channel makes the same noises, but even worse! Whenever I turn the gain pot to around 9-10 o clock, I get those noises and clear as day FM radio interference, 103.9. This is with the VHD knob all the way to the left. Now, if I engage the VHD knob a tiny bit, the RFI goes away (just for your information, the station who I am picking up has an antenna located about only two miles from my house).
Also, if I increase the gain a bit, the RFI also goes away. Seems that perhaps, if you live close to radio stations, Alpha Channel is more susceptible to RFI than other preamps? I tried everything to fix this. I plugged it into practically every outlet in my house, upstairs and downstairs. Picked up the RFI everywhere. I mean, I know for a fact that I have good cables and that I am grounded. I also have several other Class A preamps(Alpha is AB I believe, don't know if that could have anything to do with it)that don't ever do this. I dunno, at least I'm not the only one. I just might have to send mine in as well. Jim@SSL, you sure you've never heard of this with Alpha Channels before?

2Loud · 30th April 2011

there is "noise" trouble with the input pot from the beginning
- lots of user reports, have same experience, however it
crackles only in when in move / turn, no appearance in signal.
surprised SSL still ignores - there were dozens of questions
about it on different sites..

Matt Syson · 30th April 2011

Hi
So you should phone or Email SSL and get a proper reply for these 'troubles'.
If there is no real response then return them to SSL or it's dealer using the 'proper' proceedure and then ask / demand your money back.
If you buy a 4 quid toaster (about 5 or 6 Dollars) from your local supermarket and it fails to make toast you would take it back and would get a refund.
Jim@SSL is sticking his neck out by 'representing' SSL on this forum and is correctly trying to establish and ascertain repeatable facts and I only hope for his sake that 'management' are responding correctly to the concerns that are being raised.
Matt S

2Loud · 3rd May 2011

These "troubles" actually exist, and not in small amounts
but they haven´t any serious impact on signal...
its just bit weird, but hey
it works...
maybe like new toaster loosing paint after first toasting,
still toasts!!

Matt Syson · 4th May 2011

He
Effects such as 'RF pickup' and 'scratchy pots' are part of the design compromise (in common with MUCH gear). It may be there is insufficient space or serious cost implications to 'improving' the overall design.
If tested to extremes almost ALL gear will have 'problems' of this nature to some extent.
Yes they can be improved in many respects but it may impact on other aspects.
SSL know how to make excellent gear and I cannot explain why this particular unit (according to this thread) seems to have a problem.
I would be interested in opening one up and finding out what is going on sometime.
Matt S

fullscale · 4th May 2011

From the SSL FAQ site:-

'When the gain pots on my Xlogic SuperMicPre are in motion, I can hear an increase in noise during the gain transition?

A small amount of audible noise when the pots are in motion is expected. This is a combination of motor control cross talk, DC servo technology and mechanical noise created as the wiper moves over the potentiometer tracks. With the large amounts of gain and the implementation of direct coupled Super Analogue technology within the input amp circuit these small artifacts are inevitable. The designer has traded a small amount of pot transition noise to ensure the integrity of the sonic performance.'

Not the same unit granted, but a similar scenario. It sounds like in order to keep the signal integrity there's a trade off of an audible noise when the pot is being turned.

Matt Syson · 5th May 2011

Hi
Good, so it is using DC coupled circuitry which will 'suffer' some artifacts when the circuit conditions are changed.
ALL pots create SOME noise when operated although it depends on type, composition and speed of operation (among others) to determine how much noise.
The usual way to avoid the majority of these noises is to have a capacitor to prevent DC conditions from changing but they have chosen not to do this for signal integrity.
Matt S

Edwards · 6th May 2011

Happy to report that my Alpha Channel is as quiet as a mouse until I tell it to be loud!

drtechno · 10th May 2011

its because they used the wrong type of control applied to that circuit. but, just thier quirks.

leutholl · 19th May 2011

I bought my SSL Alpha Channel brand new and have the same noise. Actually two issues:

1) FM-like sound sweeping up and down whenever I push a button or change a knob that is in the signal chain. It disappears after 10s but I wonder if it's still there or if I can't just hear it anymore (frequency to high...). Turning the VHD a little up helps.

2) the lite limiter introduces clicks when it engages to start limiting. there is a crackling noise when the LED goes from green to orange and if you have a sound with a long sustain flipping around the limiter threshold you have some much clicking noise that you really have to switch the limiter off...

Now as for 1) i can understand that when the signal is DC coupled that such artifacts can occur. Not too much of a problem for me. but 2) is killing the sound....

I'm wondering if you guys have ever came across the 2) problem. And if yes, maybe there is a workaround....

I'm can't send the SSL back as I bought it in another country and it won't cover warranty in my country... ;-(

Thanks.

Matt Syson · 19th May 2011

Hi
I doubt there is a 'workaround' if noise 2 is that bad. It needs to go to a dealer or back to SSL. Not sure what the suituation is but someone should take responsibility for NEW units.
What sound source are you working with?
Matt S

leutholl · 20th May 2011

I use it as a preamp for my passive Rhodes Mark I (unbalanced Jack plug). Will try with other sources soon...
Does SSL cover warranty in all countries even if I didn't buy it in my home country?! Apple does and Avid too! Maybe they will exchange it here in Switzerland. (I bought the unit in England at digitalvillage).

Thanks.

Matt Syson · 21st May 2011

Hi
Talk to Digital Village about it. Apart from large carriage costs it should be the same as if you lived in northern Scotland or somewhere distant from them.
Matt S

oxide54 · 21st May 2011

persistance is definately key to dealing with them, thats all i'm saying.

bryanta1999 · 31st January 2012

@PsilohsaiBiN I am having the same problem. I have been having the problem since I bought it but didn't pay it much mind as when I turned the VHD it would go away, but i recently started to investigate and notice that it was a radio station that was being picked up. As I went to record I would hear the radio station behind my voice as clear as day. it actually sounded better than my car radio. SSL said they have never heard of this, but when I found this thread and noticed that a lot of people have been having this problem I told them that I was not the only one and to reference the thread.

12th February 2010	#2
Matt Syson Lives for gear Joined: Sep 2004 Location: UK Posts: 4,822	Hi So you get back onto the dealer and say you are still unhappy, that is what they are for. Matt S __________________ Matt S www.mseaudio.co.uk

12th February 2010	#3
Jim@SSL Solid State Logic Joined: Nov 2006 Location: Oxford, UK Posts: 1,443	Is anything connected to the input? Any cables etc? As the previous poster suggests, if this is a replacement unit under warranty you should go back to the dealer. Sorry to hear of the problem - this is not a known issue to us. __________________ Head of Workstation Partner Products Business Solid State Logic New Nucleus setup videos for ProTools, Logic, Cubase, and Ableton now online http://www.youtube.com/sslvideos

12th February 2010	#4
MIKEHARRIS Lives for gear Joined: Jul 2002 Location: MIAMI FLA Posts: 1,685	i recently learned that if youre leaving the ALPHA Channel digitally...you need to put a SPDIF cable from your digital interface to the SDIF in ...so the A C will know what clock rate you are using. Without...you will have pops & clicks __________________ harrisaudiosystems.com

12th February 2010	#5
frabo Gear interested Joined: Jan 2010 Posts: 17 Thread Starter	Thank you for your fast response. Jim, I have these noise with nothing connected to the unit. Just the output to a mixer and turn the gain pot ... I'm in contact with the ssl support and I will bring it back to the dealer tomorrow! But I'm very scared about exactly the same problem with the "new" unit !? And I wonder that all of you with an Alpha Channel doesn't have any scratchy noise when you turn the gain from 50% up to the last quarter ... Ahh, I checked it again, and I figured out that the scratchy noise is not so loud if you turn the VHD up to 50 % ...!? And it is mor or less away when VHD is 100% .... But if VHD is 0% it is terrible ! I'll let you know how this story ends... f. Last edited by frabo; 12th February 2010 at 11:45 PM.. Reason: news

29th April 2011	#8
PsilohsaiBiN Gear Head Joined: Oct 2010 Location: Long Island, NY Posts: 66	Wow, I know this thread has been dead for about two months but I have a similar problem. My Alpha Channel makes the same noises, but even worse! Whenever I turn the gain pot to around 9-10 o clock, I get those noises and clear as day FM radio interference, 103.9. This is with the VHD knob all the way to the left. Now, if I engage the VHD knob a tiny bit, the RFI goes away (just for your information, the station who I am picking up has an antenna located about only two miles from my house). Also, if I increase the gain a bit, the RFI also goes away. Seems that perhaps, if you live close to radio stations, Alpha Channel is more susceptible to RFI than other preamps? I tried everything to fix this. I plugged it into practically every outlet in my house, upstairs and downstairs. Picked up the RFI everywhere. I mean, I know for a fact that I have good cables and that I am grounded. I also have several other Class A preamps(Alpha is AB I believe, don't know if that could have anything to do with it)that don't ever do this. I dunno, at least I'm not the only one. I just might have to send mine in as well. Jim@SSL, you sure you've never heard of this with Alpha Channels before? Last edited by PsilohsaiBiN; 29th April 2011 at 03:27 AM.. Reason: cause

15th February 2010	#7
frabo Gear interested Joined: Jan 2010 Posts: 17 Thread Starter	I know about that. I don't want to talk about VHD. I just want to tell you about the settings where the machine makes the worst sound. Please, all of you with an Alpha channel, try the settings like this if you have scratchy sounds with the gain pot. Or is it just me with now two broken units?

30th April 2011	#9
2Loud Lives for gear Joined: Jan 2009 Posts: 569 1 Review written	there is "noise" trouble with the input pot from the beginning - lots of user reports, have same experience, however it crackles only in when in move / turn, no appearance in signal. surprised SSL still ignores - there were dozens of questions about it on different sites..

3rd May 2011	#11
2Loud Lives for gear Joined: Jan 2009 Posts: 569 1 Review written	These "troubles" actually exist, and not in small amounts but they haven´t any serious impact on signal... its just bit weird, but hey it works... maybe like new toaster loosing paint after first toasting, still toasts!!

4th May 2011	#12
Matt Syson Lives for gear Joined: Sep 2004 Location: UK Posts: 4,822	He Effects such as 'RF pickup' and 'scratchy pots' are part of the design compromise (in common with MUCH gear). It may be there is insufficient space or serious cost implications to 'improving' the overall design. If tested to extremes almost ALL gear will have 'problems' of this nature to some extent. Yes they can be improved in many respects but it may impact on other aspects. SSL know how to make excellent gear and I cannot explain why this particular unit (according to this thread) seems to have a problem. I would be interested in opening one up and finding out what is going on sometime. Matt S

4th May 2011	#13
fullscale Gear Head Joined: Jun 2005 Posts: 30	From the SSL FAQ site:- 'When the gain pots on my Xlogic SuperMicPre are in motion, I can hear an increase in noise during the gain transition? A small amount of audible noise when the pots are in motion is expected. This is a combination of motor control cross talk, DC servo technology and mechanical noise created as the wiper moves over the potentiometer tracks. With the large amounts of gain and the implementation of direct coupled Super Analogue technology within the input amp circuit these small artifacts are inevitable. The designer has traded a small amount of pot transition noise to ensure the integrity of the sonic performance.' Not the same unit granted, but a similar scenario. It sounds like in order to keep the signal integrity there's a trade off of an audible noise when the pot is being turned.

5th May 2011	#14
Matt Syson Lives for gear Joined: Sep 2004 Location: UK Posts: 4,822	Hi Good, so it is using DC coupled circuitry which will 'suffer' some artifacts when the circuit conditions are changed. ALL pots create SOME noise when operated although it depends on type, composition and speed of operation (among others) to determine how much noise. The usual way to avoid the majority of these noises is to have a capacitor to prevent DC conditions from changing but they have chosen not to do this for signal integrity. Matt S

6th May 2011	#15
Edwards Gear maniac Joined: Oct 2008 Location: Tokyo, Japan Posts: 204	Happy to report that my Alpha Channel is as quiet as a mouse until I tell it to be loud! __________________ http://danieledwards.net http://myspace.com/danieledwardsmusic

10th May 2011	#16
drtechno Lives for gear Joined: Aug 2006 Location: Rapid City, SD Posts: 602	its because they used the wrong type of control applied to that circuit. but, just thier quirks. __________________ In live sound, we make the band one with the environment, In recording, we define the environment in which the vision of the song is recorded.

19th May 2011	#17
leutholl Gear Head Joined: Jan 2009 Location: Switzerland Posts: 42	I bought my SSL Alpha Channel brand new and have the same noise. Actually two issues: 1) FM-like sound sweeping up and down whenever I push a button or change a knob that is in the signal chain. It disappears after 10s but I wonder if it's still there or if I can't just hear it anymore (frequency to high...). Turning the VHD a little up helps. 2) the lite limiter introduces clicks when it engages to start limiting. there is a crackling noise when the LED goes from green to orange and if you have a sound with a long sustain flipping around the limiter threshold you have some much clicking noise that you really have to switch the limiter off... Now as for 1) i can understand that when the signal is DC coupled that such artifacts can occur. Not too much of a problem for me. but 2) is killing the sound.... I'm wondering if you guys have ever came across the 2) problem. And if yes, maybe there is a workaround.... I'm can't send the SSL back as I bought it in another country and it won't cover warranty in my country... ;-( Thanks.

20th May 2011	#19
leutholl Gear Head Joined: Jan 2009 Location: Switzerland Posts: 42	I use it as a preamp for my passive Rhodes Mark I (unbalanced Jack plug). Will try with other sources soon... Does SSL cover warranty in all countries even if I didn't buy it in my home country?! Apple does and Avid too! Maybe they will exchange it here in Switzerland. (I bought the unit in England at digitalvillage). Thanks.

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21st May 2011	#20
Matt Syson Lives for gear Joined: Sep 2004 Location: UK Posts: 4,822	Hi Talk to Digital Village about it. Apart from large carriage costs it should be the same as if you lived in northern Scotland or somewhere distant from them. Matt S

21st May 2011	#21
oxide54 Lives for gear Joined: Nov 2008 Posts: 1,011	persistance is definately key to dealing with them, thats all i'm saying.

31st January 2012	#22
bryanta1999 Gear interested Joined: Jan 2012 Location: Atlanta, GA Posts: 1	@PsilohsaiBiN I am having the same problem. I have been having the problem since I bought it but didn't pay it much mind as when I turned the VHD it would go away, but i recently started to investigate and notice that it was a radio station that was being picked up. As I went to record I would hear the radio station behind my voice as clear as day. it actually sounded better than my car radio. SSL said they have never heard of this, but when I found this thread and noticed that a lot of people have been having this problem I told them that I was not the only one and to reference the thread.