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Bi-amping my Quad 22L2 towers

Hi folks, been a long time since I posted here, and I have learned a lot on this site since I bought my first set of decent floorstanders in 2009. I have a question that my research into the manuals and other internet sources is not answering. This is likely because my speakers are old and out of production. I was wondering about bi-amping my Quad 22L2s. They are 2.5 way towers, with two sets of binding posts on the back panel, split between HF and LF. I just bought a Jolida 3502s integrated and I am losing some of the pinpoint imaging I get with my Parasound separates (P3 and A23). Wondering about hooking up the Jolida taps into the HF posts, then connecting the A23 to the Jolida using the variable outputs on the back of the 3502s integrated, and running taps from the A23 to the LF posts. This way I still get the tube effect in the pre-amp stage. Would that fry the internal crossover on the Quads? Would I have to open the Quads up and remove the internal crossover and use an external, active crossover to achieve any real benefit? Would this be any different than just using the Jolida as a tube-pre? Thanks in advance.
realremo

Showing 2 responses by almarg

almarg's avatar
almarg
9,670 posts
 
@realremo
... simply running the quads off of the variable outputs of the Jolida and using it as a tube pre.

NO!!!  Doing that is what could cause damage, to the Jolida. Recall that running a tube amp unloaded can result in damage to the output transformers and/or the output tubes, due to what is known as "inductive kickback" or "inductive kick." And damage is especially likely if the amp is operated unloaded while its output stage is processing a signal, which is what would happen if you were to do this.

If you want to do this, load resistors should be connected to the outputs of the amp. 8 ohm resistors rated to handle 100 watts or thereabouts, or 16 ohm resistors rated to handle 50 watts or thereabouts, would be suitable.

Good luck. Regards,
-- Al

almarg's avatar
almarg
9,670 posts
 
After looking at the specs and descriptions of the 3502s and the A23, and the manual for the speakers, and doing some calculations regarding gain, it appears to me that the passive biamp configuration of those components that you proposed (without an active crossover) would be safe and would work. I wouldn’t want to speculate, though, on whether the resulting sonics would be better or worse than what you have now.

In doing so, you would most probably find that you would have to somewhat reduce the settings of the gain controls on the rear panel of the A23 from their max ("THX Reference") position, in order for the gain of that amp to match the gain of the power amp section of the 3502s. Otherwise bass frequencies would be overemphasized.

Regards,
-- Al
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