[GAD]

I just got a new in box GS-1 with stepped attenuator in a trade. Beautiful amp, but I'm having what seems like a problem.

Putting this amp in place of my XP-7, the GS-1 delivers anemic sound with painfully little volume.

Where I have the XP-7 knob at say 10:00 for loud rockin' volume, I can put the GS-1 to max and still wish for more, even on high-gain. I get the same result on either input.

My chain is FLAC (Foobar) -> S/PDIF -> Lavry DA10 -> XLR-RCA -> GS-1 -> Senn HD-650.

If I keep everything the same and swap out the GS-1 for the XP-7, I'm blown away. Compared with the GS-1, I get substantially more volume from the DAC's headphone jack. Hell my Hornet on low gain blows this amp away.

From what I've read, something ain't right. I got the unit sealed NIB from someone I trust, so I'm wondering if maybe there's a problem with the unit?

I'd love to find out that there's a jumper I need to pull somewhere...

Thanks,

GAD

 

[GAD]

I also get the same results on either headphone jack.

GAD

 

[GAD]

Talk about awesome service - I'm already talking with Justin about it...

GAD

 

[daltonlanny]

GAD,
Just curious...
What did you find out from Justin about the problem?

 

[GAD]

I'll post more when I have a definite answer. We're pretty much there, but it wouldn't be fair to him to post speculation.

GAD

 

[randyruiz]

The XLR out of the DA10 is balanced and in most cases the XLR-->RCA adapter will convert to single ended. You might be in a situation where there is no conversion between balanced and single ended.

I am not sure what kind of problem this can cause (feeding a balanced signal to a single ended amp) but it is somewhere to look. The DA10's XLR outputs can be converted to Single ended by jumpers inside the DAC. Check the manuals and adjust.

 

[spraggih]

Well I am glad it seems to be working out. I also hope when the time is right and you have all the specifics that you post the resolution so others who uncover the same thing can search and find the potential answer.

But I completely understand waiting until you know all the facts and have a resolution that is tested.

 

[GAD]

It seems there are two issues:

1) The amp was originally ordered with the low gain "set to unity". I'm not sure why, but the original owner ordered it that way. That in and of itself was really not an issue, though it added to the "this amp is too weak" feeling.

2) When Justin built the amp, he seems to have built it with Gilmore Lite gain specs on high (6X) vs GS-1 specs (8X).

This coupled with the fact that the amp I'm used to (RSA XP-7) has a much higher gain, AND the fact that "the curve on the DACT volume controls means you have to turn it up substantially higher than most volume pots" made me feel that the amp was inadequate.

Justin will fix the high gain and adjust the low gain back to normal for me at no charge (I pay to ship it).

I would like to say that Justin was *awesome* through all of this. He had me measure voltages at loop-out and pre-out using test tones and various volumes (I love my fluke!) until he knew what the problem was.

He was patient, methodical and always polite and helpful.

A+ for customer service!

GAD

 

[GAD]

Quote:

Originally Posted by randyruiz /img/forum/go_quote.gif The XLR out of the DA10 is balanced and in most cases the XLR-->RCA adapter will convert to single ended. You might be in a situation where there is no conversion between balanced and single ended. I am not sure what kind of problem this can cause (feeding a balanced signal to a single ended amp) but it is somewhere to look. The DA10's XLR outputs can be converted to Single ended by jumpers inside the DAC. Check the manuals and adjust.

Thanks for the idea. I had already tried that, but it was still an excellent observation.

GAD

 

[Andrew_WOT]

Quote:

Originally Posted by GAD /img/forum/go_quote.gif Justin will fix the high gain and adjust the low gain back to normal for me at no charge (I pay to ship it).

I would leave it at unit for low gain. That makes tuning volume for sensitive cans much easier with DACT, you have finer control at low gain and less overlap between low and high gain. Hope that makes sense.

 

[GAD]

Why would there be finer control? Wouldn't the steps be the same, only starting at a lower volume?

GAD

 

[Andrew_WOT]

Quote:

Originally Posted by GAD /img/forum/go_quote.gif Why would there be finer control? Wouldn't the steps be the same, only starting at a lower volume? GAD

http://www.head-fi.org/forums/showthread.php?t=166438

And Justin's explanation
Quote:

Many people find even in the low gain position, they never go over 12 o'clock on the volume knob. This means with a stepped attenuator, you're only going to get about 8-10 different volume levels to choose from. But the stepped attenuator has 23 positions total, so the rest are wasted. By lowering the gain so that when the volume control is maxed out, it is basically what used to be 12 o'clock, you have more precise volume positions to choose from. With a volume pot (standard) this isn't an issue.

 

[GAD]

Interesting - thanks!

GAD