Bi-amping MBL 101's - combining tube & ss

If your main amp's speaker connections inside your speaker's are equally split or "Y'ed" to each driver's crossover, it should be doable. Your "extra" pre-amp gain is key. Splitting the pre-amp signal has to meet the input sensitivities of both amps.

You would disconnect your speaker's "split" leads to the bass driver's crossover, and leave the upper driver(s) connections intact to your current amp.

Then, connect your new amp to the bass driver's input crossover. If no input crossover is used, then, connect the new amp directly to the bass driver. How each speaker section, bass and trebles, responds to gain from two different amp's is a balancing trick. The input sensitivity and output ratings of both amps should be matched carefully to even out the bass and treble responces so different levels of gain result in even volume level gains for two different amps.

If bass and treble balance is a problem, I'd consider adding a good quality attenuator or volume controller on the bass driver like a subwoofer's gain is adjusted for different recordings and rooms. A higher end Niles volume controller just before the bass driver connection may do it for you.

If you have enough preamp gain to split your preamp signal, another way is using a Behringer DEQ 2496. One cleanly split preamp signal pair goes to your current amp and treble drivers, and the other split pair to the Behringer's analog inputs. Then, use the analog OUT's to connect to your new bass amps. Connect the new amps leads only to your bass drivers. The Behringer's analog outs/ DAC's in lower frequencies is quite good. It also adds a good volume controller only effecting the bass driver, plus, EQ adjustments. You can use the parametric EQ and adjust +/- any frequency the bass driver reproduces. Then, adjust the main Behringer's main volume to the bass amp.

With the DEQ 2496, you can leave frequency settings to flat (leveraging your internal crossovers)or add in the parametric EQ to your taste. It also has a 12 dB boost to offset marginal preamp signals to better meet the amps input sensitivity.

I'm not a engineer, but tossing ideas out as a consideration.

Maxitonus, your reply is so misleading but obviously your own opinion and from the date saying "about 8 years ago" suggest you owned a very old model.

I own the version prior to the current MK2's as of date and there is no such metalic sound present what so ever you refer to nor the coloured sound so you have left me scratching my head wandering what the hech was wrong with your set-up.

Davidhyman, I had PM'd you previously did you receive. These speakers are true bi-wired but in relation to your question above I do not know because I have not tried and do not know of anyone who has. Possibly ask someone over at MBL but then again they will most likely just want to steer you into using their amps etc.

VAC Statement 450 mono blocks paired up with Vac's Sig. pre are a match made in heaven with these speakers period, nothing else I have heard comes close.

I second Dev advice - the "metalic" only shows in MBLs when they are not properly setup - and this includes improper room acoustics. Some amplifiers, irrespective of power could make them sound also anemic and thin, highlighting their intrinsic colorations.

My experience was with old 101C - and used with the wrong ancillaries they could sound this way. But when everything was perfect they sounded great.

I also was told that current models are much improved in these aspects, but have no experience with them

thanks dev.

what do you mean by PM'd me?

as i said, i ain't giving up the bernings! i gotta make this work or i gotta pass on the speakers.

Soundsbeyondspecs, thank you! i think i get it. i'll have to re-read a few times to fully digest.

make sure my preamp as dual outputs to two sets of amps.

might have to put some variable control between bass amp and speaker.