[jimbo]

I just made the upgrade from single-ended to balanced connections in my surround system.
The system:  SP1 - 7bst x 2 - 6bst. 
Interconnects:  Harmonic Tech. Pro Sillway II  - XLR


- Seems one of the 7bst is now playing at a much lower level than the other. I've completely troubleshot the system and have zero doubt that the problem is in one of the 7bst amplifiers. Either the gain in one is too sensitive. Or, more than likely, the gain on the other is too low (as one 7bst level matches to the 6bst set at 2V fairly well).
- This was never an issue when running these same amplifiers single-ended.

I've searched the amplifier over and can find no gain adjustment. Anyone have any idea what may be
causing this?

Thanks in advance for your assistance,
-J

[jethro]

Did you check the balanced vs un-balanced switch ?

Are they PRO amps ? If so are the pots adjusted to full scale ?

When you say "completely troubleshot" did you switch the 7B-ST
by themselves and leave everything else un-touched ?

Are your SP-1 channel levels set correctly ?

Are you using an analog source thru the SP-1 bypass ? If so
is your source ok on both channels ?

I'm not sure if this matters, but is your speaker's polarity correct ?

You've probably checked all of these already but just in case...

HTH, Steve

[jimbo]

Yep, checked all that stuff. -
No, they're not pro model amps with user adjustable gain.

When using a digital input, the SP-1's level (with one of the 7bst) must be "boosted"
nearly 8db to equal the volume of the other channels. -
When using 2-channel paypass, the level of one 7bst clearly overpowers
the other. An adjustment to the balance control of nearly 50% towards the
quieter channel is required to brings their levels back into similarity.
Again, there are no issues when using the single-ended connections.

There seems to be no sonic difference between the two 7bst other than their gain (which seems fixed).

I'm really confused by this...   

Did you check the balanced vs un-balanced switch ?

Are they PRO amps ? If so are the pots adjusted to full scale ?

When you say "completely troubleshot" did you switch the 7B-ST
by themselves and leave everything else un-touched ?

Are your SP-1 channel levels set correctly ?

Are you using an analog source thru the SP-1 bypass ? If so
is your source ok on both channels ?

I'm not sure if this matters, but is your speaker's polarity correct ?

You've probably checked all of these already but just in case...

HTH, Steve

[James Tanner]

Have you tried reversing the 7B's in the system to make sure the problem stays with the specific 7B?

james

[jimbo]

Yep, sure have. - One definitely plays at a lower level than the other.

Have you tried reversing the 7B's in the system to make sure the problem stays with the specific 7B?

james

[James Tanner]

OK sounds like we need to get it in for service.

james

[jimbo]

I was afraid of that.
I shall contact service.

Thanks for your assistance,
-Jim

OK sounds like we need to get it in for service.

james