Gain Pots on ST PRO series amps

jethro · « **on:** 19 Mar 2005, 11:45 pm »

James,

My system now has two spare channels on my 8B-ST PRO that I could use for bi-amping my left and right IB1. If I use the balanced and un-balanced output s on my SP-1.7 then I could avoid using an un/balanced splitter cable, however, I believe I would have to adjust the balanced amp down by 6 dB using the gain pots. Are the gain pots on the PRO series linear ? i.e. will half of the pot travel give me -6.5 dB ?

I have the parts to make a splitter cable, I just thought I would see if bi-amping makes any changes before making a new set of cables.

Thanks.

James Tanner · « **Reply #1 on:** 20 Mar 2005, 12:21 pm »

Hi Jethro,

The Gain from the 5.1 Balanced and Unbalanced outputs on the SP1.7 are the same. We did it that way so you could mix and match the outputs without a difference in the volume/gain from channel to channel.

james

jethro · « **Reply #2 on:** 26 Mar 2005, 03:23 am »

James,

I'm still confused. I currently use the center and sub-woofer balanced outputs on my SP-1.7 into a 4B-ST since my unbalanced sub-woofer output on my SP-1.7 doesn't work (waiting for the next SP-1.7 upgrade to get it fixed). I use the left and right front un-balanced outputs from my SP-1.7 into another 4B-ST. I have IB1's for the left, and right, and center. I always have to set my center output level trim 6 dB (actually 5.5 dB) lower than my left and right front when using a sound level meter to calibrate my system. Since my SP-1.7 is actually an upgraded SP-1, would the un-balanced/balanced output levels be different ?

Thanks.

James Tanner · « **Reply #3 on:** 26 Mar 2005, 12:52 pm »

Hi Jethro,

Maybe I am wrong on this one - I will find out on Monday for you.
Come to think of it I use the RCA outs for my Back 6th and 7th channels and the 5.1 balanced for my LCR LS RS and SUB and I do have to increase the Back 6 and 7th by 5DB.

james

James Tanner · « **Reply #4 on:** 28 Mar 2005, 04:13 pm »

HI Jethro,

Your right - I'm wrong.
Checked with engineering and the XLR balanced outs on the SP1.7 are 6dB hotter than the RCA's.

james

jethro · « **Reply #5 on:** 28 Mar 2005, 08:29 pm »

Thanks James.

I think I will just use my RadioShack sound level meter to reduce my amp's gain instead of trying to guess how far to turn the pots.