Pass Labs Aleph Question - balanced vs unbalanced?

Ghostrider45 and Wloeb,
Thank you both for the explaining the design of Aleph amps. As an owner of Aleph 5, I've tried all three types connections: balanced, RCA w/ shorting pin, RCA w/o shorting pin, all from ML No. 39. My question is, from the circuit design point of view, what are the benifits or drawbacks of not connecting the shorting pin on the XLR input when operating throught the RCA input? On the other hand, does the input impedence change at the RCA input when the XLR shorting pin in inserted? Though this may not produce much effect as the 39 has pretty low(<50?) output impedence. Thanks.

A quick comment about the shorting pin - I don't know why but my current Comcast HDTV feed is very low in volume. Commercials are normal, which is infuriating as I have the volume super high for the show, and then the commercials are defeaning - but anyway - The Aleph 5 is not powerful enough without the shorting pins in place when used via RCA in for me.

All that to say, 1) I hate Comcast, and 2) with the shorting pins in, you will get more power.

I'll quote the aleph 5 manual:

"The Aleph 5 is shipped with a shorting plug between pins 1 and 3 of the input XLR connectors. This shorting plug sets the gain of the amplifier to 26 db when you are using the RCA unbalanced input. Removal of this plug will set the gain to 20 db. Needless to say, you will remove this plug when using the balanced input. There is no penalty for not using this plug withunbalanced operation, and if you ahve particualrly efficient loudspeakers, you may find that you prefer it this way."

Note that I haven't had the chance to get shorting pins (originals lost long ago) and I am currently using 2 twisted and bent paperclips in each pin, with no noticeable decrease in sound quality. He he.....

Lightminer,
Indeed, with the manual in hand, I've been wondering more than once what Nelson Pass was hinted at when he said "...with...efficient speakers, you may find you prefer it this way". Prefering the extra volume range offered by the 6 dB difference, if one uses, say, horn speakers that simply blast out at lowest volume settings when pin 2/3 are shorted? I doubt. Sounds like a gain in quality instead of quantity. Maybe just ask Mr. Pass...Anyway, it's easier to ask questions than dragging out my Horowitz and pretend I am EE major. The 6 dB is easily adjusted by the No. 39 to compare the effect of shorting pin 2/3, and to tell the truth, just like you said, with the pin, it's more powerful. But it's accompanied by a little edge on transients, which might bring the perceived soundstage closer. Kind of like the passive/active difference in preamps.

Agreed - I know he is big on 'fewer gain stages are better' in general, maybe it skips some amplification circuitry - shorter circuit path? Must be something like that. With pin in place it must somehow participate in circuitry involved with the balanced operation??? Agree that without asking its all conjecture...... (But perhaps the one thing we can be definite about is it skips some amplification stage and should have shorter circuit path).