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GS 1 input switching

post #1 of 4
12/15/10 at 7:41am
Thread Starter 

I have a question on what to expect in terms on how a GS 1 (stepped attenuator) performs on input selection.

 

Last night I noticed this. Please tell me if it’s normal, or if anything may be wrong, or if I made a mistake on how I set things up.

 

Also, can anyone else reproduce this?

 

- use spare computer power cord for power

- connect CD source to Input 1 using RCA and a T-split (I will connect using pass-through later for tests as a pre-amp)

- turn power on and let warm up for 5 minutes

- set to high gain and plug phones into Jack 1 (furthest to the left while looking at the amp head on)

- play CD

- turn volume up slowly

- change setting to Input 2 with CD playing on Input 1 only (Input 2 is not connected to anything)

- after about 1/2 volume up to 100% (12 o-clock position up to 6 o-clock) I can hear the CD playing on Input 1 however I hear it on the Input 2 channel that is not connected to anything (no cables plugged in)

- repeat with cables reconnected to Input 2 and hear CD on Input 1 that is now not connected to anything (i.e. CD playing on oppiosite Input)

- repeat with various headphones (K271MkII, HD25SPII, HD650, etc)

- repeat with Jack 2

 

Please let me know if this is expected behaviour or not.

 

This does not bode well for source testing if I have this right.

 

Perhaps I connected it improperly, I am not sure.

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post #2 of 4
12/15/10 at 7:45am
Thread Starter 

I got this from Justin a few seconds ago in a PM. So no problems at all regarding expected perfromance. That part is good news. :)

 

 

 

Some bleed-through is going to be expected between the 2 inputs, because it is just a simple 2-way switch that selects the input.  

 

Thanks,

Justin

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post #3 of 4
12/15/10 at 9:45am

 

Quote:
Originally Posted by ipm View Post

- after about 1/2 volume up to 100% (12 o-clock position up to 6 o-clock) I can hear the CD playing on Input 1 however I hear it on the Input 2 channel that is not connected to anything (no cables plugged in)

- repeat with cables reconnected to Input 2 and hear CD on Input 1 that is now not connected to anything (i.e. CD playing on oppiosite Input)

 

This does not bode well for source testing if I have this right.

 


How frequently do you run high gain and more than 1/2knob spin in actual use? For most people the answer is very rarely. If you do need this much gain & volume knob, you probably have a very low output source (which wont bleed through) or very insensitive headphones (which wont pick up the bleed through).

 

Many preamps/source selectors have bleed through if you really turn things up. I wouldn't worry about it.

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post #4 of 4
12/15/10 at 11:38am
Thread Starter 

nikongod,

 

That's what I was thinking over lunch as well, and that is probably what I will convince myself of soon enough.

 

Other than that issue, the amp is pretty good so far.

 

I just was not expecting the bleed through.

 

You say many have this problem. Is this related to design, price, or parts quality? The answer is probably not from what my limited knowledge tells me. Even so, perhaps the source select switch itself can be improved somehow. Those are random thought though.

 

In any case, I will play with the amp some more over the next week or two to see what I think.

 

Regards,

 

ipm


Edited by ipm - 12/15/10 at 11:39am
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