need help on XP 20 (pass thru )

[TOGA]

Hi,
I got a used XP20 and I didn't know where it come from, but surprisingly, there is no serial no. on the back. Anyway it works just fine until today when I connected it to home theater system.
Ok, according to user manual version 2008, to operate pass-thru here is what to do
1. connect pre/pro to input 5
2. press pass-thru button on remote controller twice, then the volume will show 64P 64P, that mean preamp will work as 0dB gain.
3. to exit, press pass-thru once, volume will automatically show 00P 00P

On 2011 version manual, the pass-thru works on 75P 75P instead and once exit, input and volume will return to the last setting.

BUT, on my unit, pressing pass-thru twice bring the input 5 level to 59P 59P, and I can still adjust the volume to anything xxP, but I tried to increase
64P to match the user manual (2008) but it maxed at only 63P. The worst is that once I exit the pass-thru the volume changed to 59L 59R instead of 00L 00R as user manual stated. Much believe in XP20 I switch to input1 expecting the volume to be 00 but Boom !! the CD played at volume 59L 59R my ear drum and tweeter were almost fried.

Without serial no. I doubt I could get any help from local dealer.

Any advice ?

Toga

[turntable]

Hi Toga

perhaps have a read of this review - it states max vol is 63 low gain and 68 high gain. You might be doing something wrong?

Have you played around with the high and low gain settings - It looks like you are still on low gain setting.

Pass Labs XP-20 Preamplifier Review - Dagogo | A Unique Audiophile Experience

Mine is the current release, so works with 75P on pass thru and back to zero if I change input from 5 to any other. First time I have pressed the HT button was now :-)

cheers

[TOGA]

Thanks
Mine was set in low gain. Can't imagine what would happened if it was at high when
I disengage HT mode. The volume number in HT mode is not a great concern as much
as not-return-to-zero. it is very dangerous.

now in contact with Pass directly, but first thing they asked for is serial numbers, which
I do not know, but he said the other place where I can find serial number in on the bottom. I will check. I hope this is just a software problem. a new EPROM would fix this.

otherwise, as I bought it used, I just resale and find other unit or upgrade to XP30.

Toga

P.S. no surprise that this was your first time to press this HT button, nobody at local dealer even know how it work. it is seem to be unpopular function in high end preamp.
but for my system, it is an essential. I even need XLR Bypass in for my main system, this XP20 is used in secondary system.

[TOGA]

FYI
My XP20 has been taken care of directly by Pass's worldwide technical support department.
They will program me a new PROM with reasonable charge. And I cannot even
tell them the serial number.
What a great service.

Toga

[BlueFox]

Originally Posted by TOGA

The volume number in HT mode is not a great concern as much as not-return-to-zero. it is very dangerous.

The volume number in regular two channel operation is also dangerous. For whatever reason, Pass calibrated the volume of the XP-20 to be between 0 and 83! What kind of a scale is that?

I toasted the tweeter and mid-range on my right Magico S5 one night while incrementally bumping up the volume on the Pass X600.5 amps to see how loud the S5s could play. I was expecting at some point to hear clipping or distortion. Something to indicate I found the limit. At 83 I was thinking this sounds great, but it is just way too loud. Just as I was going to back off, the right speaker went dead. The whole time I was doing this 'experiment' I was thinking 100 was the max, not 83. What kind of a scale is that?

Oh well, live and learn. Expensive lesson, though.

[Masterlu]

Originally Posted by BlueFox

The volume number in regular two channel operation is also dangerous. For whatever reason, Pass calibrated the volume of the XP-20 to be between 0 and 83! What kind of a scale is that?

I toasted the tweeter and mid-range on my right Magico S5 one night while incrementally bumping up the volume on the Pass X600.5 amps to see how loud the S5s could play. I was expecting at some point to hear clipping or distortion. Something to indicate I found the limit. At 83 I was thinking this sounds great, but it is just way too loud. Just as I was going to back off, the right speaker went dead. The whole time I was doing this 'experiment' I was thinking 100 was the max, not 83. What kind of a scale is that?

Oh well, live and learn. Expensive lesson, though.

How many db's do think you were hitting?

[BlueFox]

That night I was just listening, but it was definitely more powerful. Until then, I kept the max volume number in the low-mid 70s. Depending on the song, the Radio Shack digital SPL meter could easily dance in the low 100s, and bounce over 110, with response Fast, weighting C.

[turntable]

Originally Posted by BlueFox

The volume number in regular two channel operation is also dangerous. For whatever reason, Pass calibrated the volume of the XP-20 to be between 0 and 83! What kind of a scale is that?

I toasted the tweeter and mid-range on my right Magico S5 one night while incrementally bumping up the volume on the Pass X600.5 amps to see how loud the S5s could play. I was expecting at some point to hear clipping or distortion. Something to indicate I found the limit. At 83 I was thinking this sounds great, but it is just way too loud. Just as I was going to back off, the right speaker went dead. The whole time I was doing this 'experiment' I was thinking 100 was the max, not 83. What kind of a scale is that?

Oh well, live and learn. Expensive lesson, though.

Not sure I even understand the statement.

Pass has documented that there are 83 x 1db steps from -73db to + 10db of gain.

That is 0 - 83 on the volume control.

What do you expect Pass to do to better help? Sometimes, even us males need to read the manual.

btw, +10db gain is not that high as lots of other pre amps go to +20 and +25db gain.

To me it sounds like Magico speakers don't play very loud without failing.

If nothing was distorting when playing, can't understand how one can blame the pre amp.

[TOGA]

Originally Posted by BlueFox

The volume number in regular two channel operation is also dangerous. For whatever reason, Pass calibrated the volume of the XP-20 to be between 0 and 83! What kind of a scale is that? I toasted the tweeter and mid-range on my right Magico S5 one night while incrementally bumping up the volume on the Pass X600.5 amps to see how loud the S5s could play. I was expecting at some point to hear clipping or distortion. Something to indicate I found the limit. At 83 I was thinking this sounds great, but it is just way too loud. Just as I was going to back off, the right speaker went dead. The whole time I was doing this 'experiment' I was thinking 100 was the max, not 83. What kind of a scale is that? Oh well, live and learn. Expensive lesson, though.

With normal source, I really curious how your ears withstand that level of sound. I will never used the number on display
As an indicator when I should stop, I use my ear drum. No speakers and amplifier will have a chance to survive from preamp at max volume for long. Not even the PA system. Please remember to save your hearing. It will not come back Bluefox.

Toga

[BlueFox]

It wasn't very long, but long enough to damage the speakers. As I said, I was about to lower the volume when the drivers went. While it was an expensive mistake, I have to admit the performance of the speakers was impressive. To be able to play so loud, and stay composed, is outstanding. Of course, since then I have come no where near that level. Alon told me to keep an SPL meter handy and periodically check the level. The loudest I go now is in the low 90s, and that is only occasionally.