Peachtree Audio Nova - No subwoofer connection


I just switched from speakers (Martin Logan Ethos) needing no subwoofer to a pair of monitors (Reference 3A MMC Serie) which have an advertised lower limit of 40-42 Hz. This is fine for most of our listening but there are occasions, like when watching movies, when additional bass would be nice. I have a Polk Audio Micropro 4000 which seems very capable but the Nova has no dedicated connection for a sub. I talked to a Peachtree technician who said the only way to connect a sub is to use a splitter at the RCA pre-out connection dividing the signal between the Peachtree 220 amp and the sub. I tried this before and, of course, the sub works fine but it changes the overall sound in a not good way.....and I'm not good at judging minor changes.

I also use the Behringer Ultracurve 2496 in the system and separating the signal this way bypasses the sub's signal from the equalizer so auto room adjustments won't include the range of frequencies that would be produced by the sub. I suppose that if there was a dedicated sub out connection the result would be no different. Because base frequencies, though, are a big part of adjustments for the purpose of room equalization, this is a problem.

Because the 2496 has an unbalanced 1/4" aux out" it crossed my mind that it could be used for a sub. The manual doesn't seem to address this and I've not found discussions about this on the Internet. I've also not been unable to establish communication with Behringer for their help.

There's a good chance that I'm off base on some of these assumptions about this all works but if anyone has suggestions that might help with this dilemma it would be much appreciated.
128x128broadstone
ZD, the ML's are wonderful and I still have them but when I was looking for a pair of speakers for my little garage system, I came across these Reference 3A serie's and just couldn't pass them up. I don't know if you've ever heard them (these are the originals and, supposedly, only 100 were made) but IMO and for my personal taste they are one of the best I've heard. I like them as much but in a slightly different way as my ML's which are 20 yrs newer, and I was having a difficult time deciding which to keep. With the 3A's I have more latitude in amplification choices should I decide to look again into tubes and partly because of that factor the I have the ML's for sale on Audiogon, eBay and Craigslist. This takes first place in difficult decisions for change especially since I've had them for such a short time and I wasn't even looking for a change.
I appreciate the comments but I'm still having problems deciding how to go with this. I'm getting conflicting information not only from the Internet but from Peachtree Audio and Polk Audio as well. Peachtree says the only way to feed to the sub is to use a splitter from the pre out to deliver signal to the amp and powered sub simultaneously. I tried this and, of course, it worked but, and I have no idea why, it resulted in overall somewhat degraded sound.

Polk told me, and this is in the Micropro 4000 manual as well, that I should parallel out from the power amp to both the main speakers and the "speaker" terminals on the sub. These terminals look like speaker level inputs as would be the inputs on a passive sub and if this were the case that connection would bypass the sub's amplification circuitry; they assured me that this is not the case and all capabilities would remain operational such as volume, phase control, room balancing, filters, etc. I'm confused. Having a speaker level signal delivered to anything other than directly to a driver makes no sense unless their is some attenuation circuitry reducing the signal level. Also, what about the impedance reduction resulting from paralleling the speaker outputs.

I mentioned earlier that I have a Behringer DEQ 2496 that can accommodate a sub. I can put it back in the system if it comes to that but I prefer to keep it simple where I can. My experience with the use of subwoofers is limited to my years ago home theater listening at which time my amplification equipment all had dedicated sub outputs. As you all can tell my knowledge on the subject is also quite limited so I need help.
"These terminals look like speaker level inputs as would be the inputs on a passive sub and if this were the case that connection would bypass the sub's amplification circuitry; they assured me that this is not the case and all capabilities would remain operational such as volume, phase control, room balancing, filters, etc. I'm confused. Having a speaker level signal delivered to anything other than directly to a driver makes no sense unless their is some attenuation circuitry reducing the signal level. Also, what about the impedance reduction resulting from paralleling the speaker outputs."

I get why you think this might be a bad idea, but its not. Its perfectly OK to use the speaker cable connection the way Polk recommends.
ZD, with nearly all systems you would be correct, but not in this case.

Jim (Broadstone), I'll start with what is most important:

DO NOT CONNECT THE SUB TO THE OUTPUTS OF THE PEACHTREE 220 AMPLIFIER, unless Peachtree says it's ok, and they have said that it's not ok. I and Kijanki explained the reasons in this thread.

Although powered subs which provide speaker-level inputs almost always do in fact incorporate attenuation circuitry to reduce the signal level provided to the sub's amplifier, and although such subs almost always provide a very high input impedance to a power amplifier they may be connected to (resulting in negligible loading), the design of your specific amplifier appears to completely rule out the use of that kind of connection. At least without the use of a very specialized adapter incorporating DC blocking capacitors, as explained in the other thread.

Regarding connection of the sub to the preamp, can you tell us the exact model name or number of the Peachtree Nova? If it is this one, for example, it appears to have two individually buffered sets of outputs, each having low output impedance. Connecting one to the power amp (preferably Pre Out 1, which is described as being "discrete class A") and the other to the sub should work fine in that case. Aside, perhaps, for subtle possibilities such as ground loop issues that may arise when interconnecting three components.

Best regards,
-- Al
ZD and Al, I'm always glad when you guys respond to my concerns and I've applied your advice more than a couple of times. This one, though, is a bit scary and I probably could have provided more information for you to consider in the first place.

First, the component I'm using as a preamp is the Peachtree Nova 80WPC integrated amplifier. It has two outputs, one marked "pre out", the other is labeled "line out". I accidentally connected the amp to the line out plugs once and thought I'd blown my speakers with the incredibly loud resulting volume.

Also, Peachtree didn't tell me NOT to use the speaker level signal to the sub; they simply said that the splitter from the pre-out connections was the only way. I tried to discuss the specific issue with Polk sub but they, like me, didn't know enough to feel comfortable giving more advice than that concerning the pre-out splitter.

It strikes me that there are 2 ways to do this; the first is to use the splitter method but, and it could have been my imagination, I thought that this resulted in some sound degradation. The other is to reincorporate the equalizer. Is this a good assumption and is it the sonically the best choice?