Splitting Pre Out-OK or Not

[Scott W]

I have several pieces of audio gear and am always trying different things,so my question is ,is it alright to split the pre out with Y adapters to run cables to 2 or more amps without hurting the preamp/receiver.One of the ways I have done this is plugging 2 Y adapters into the R/L pre outs of a receiver then sending the signal back into the main in of the same receiver with one set of cables and to another power amp with another set.I don't typically run two sets of speakers at the same time but, if I did could it damage anything.

[Feanor]

I have several pieces of audio gear and am always trying different things,so my question is ,is it alright to split the pre out with Y adapters to run cables to 2 or more amps without hurting the preamp/receiver.One of the ways I have done this is plugging 2 Y adapters into the R/L pre outs of a receiver then sending the signal back into the main in of the same receiver with one set of cables and to another power amp with another set.I don't typically run two sets of speakers at the same time but, if I did could it damage anything.

I have done this myself without any problems. There is little possibility of damaging the preamp or power amps, and absolutely none for the speakers regardless of whether one or two pairs are driven.

The issues would be (a) the preamp is a relatively low gain unit and cannot provide sufficient voltage to driver both power amps, and (b) having two power amps will reduce the total impedance "seen" by preamp with a resulting drop in damping factor but it is unlikely to be dangerous to the equipment.

If you have tried it and you get enough volumes and good sound, don't worry about damaging anything.

[blackraven]

Call the manufacturer of your preamp and ask them they forsee any problems with doing this.

[Scott W]

I don't think I would be able to contact the manufacter for either unit I've been doing this with,one is an old Realistic STA 2300 receiver that I believe is from the late 70s or early 80s and the other is a Harman Kardon citation 17 preamp that I have no idea of when it was made but looks like early 70s gear,it has 2 sets of pre outs but I split one set to go to a powered sub.Part of the reason I had asked this question was that I may be winning another HK amp(AVI 200II) very soon that has pre outs/main in and would like to use the front channel pre outs to drive a 2 channel system and still use the amps speaker outputs for 5 channel HT.Thanks Again

[O'Shag]

Hi Scott,

you sound like me! I do believe that in many cases biamping brings sytem performance to another level. The observation about the preamp having enough power to drive the two amps is valid. In my regular listening system, where I listen to Sirius Satellite Radio on my Dish Network VIP 622 DVR connected to a Musical Fidelity Trivista DAC driving a Carver C4000t then driving two Mark Levinson No 27s biamped, I've tried a number of configurations. I do find the Carver does run out of juice pushing two amps, which is noticable as a slight lessening of dynamic presence. Even though it has two main outs, its power supply, I think, lacks the requisite juice to drive two amps to the same degree as it can drive one.

However the following solution may be applicable to you and produces awesome results. The first pre-requisite is that your amps be capable of being driven in balanced mode. The lack in 'push' power is ameliorated by running a pair of signal cables (single-ended) to an ACTIVE balanced line driver, which converts the signal to balanced. The transformer in the balanced line driver adds gain before passing the signal through in balanced mode. For bi-amping, two splitter (Balanced XLR type) cables are required, which will be connected into the xlr output sockets fo the balanced line driver. Then two pairs of balanced cables are connected to the two pairs of balanced cables to the two amps. Its a little work to set up and will cost a bit extra because you'll need two extra pairs of balanced cables and a balanced line driver - which must be of the active variety (will be plugged in to a power socket) i.e. passive will not add sufficient gain (you don't need hi-filutin' cables and line driver, just soundly made professional quality) . The results are well worth it. Most speakers benefit considerably from bi-amping, even if they sound really good to begin with. There will be less strain to the sound and there will be a lot more of it. The soundstage will grow considerably. Problem is, with most speakers, so much amplifier power gets sucked up in the impedences of crossover networks.
By the way, the Carver C4000T is a smashing preamp especially given the price it can be had for..

[Scott W]

Hi Scott,

you sound like me! I do believe that in many cases biamping brings sytem performance to another level. The observation about the preamp having enough power to drive the two amps is valid. In my regular listening system, where I listen to Sirius Satellite Radio on my Dish Network VIP 622 DVR connected to a Musical Fidelity Trivista DAC driving a Carver C4000t then driving two Mark Levinson No 27s biamped, I've tried a number of configurations. I do find the Carver does run out of juice pushing two amps, which is noticable as a slight lessening of dynamic presence. Even though it has two main outs, its power supply, I think, lacks the requisite juice to drive two amps to the same degree as it can drive one.

However the following solution may be applicable to you and produces awesome results. The first pre-requisite is that your amps be capable of being driven in balanced mode. The lack in 'push' power is ameliorated by running a pair of signal cables (single-ended) to an ACTIVE balanced line driver, which converts the signal to balanced. The transformer in the balanced line driver adds gain before passing the signal through in balanced mode. For bi-amping, two splitter (Balanced XLR type) cables are required, which will be connected into the xlr output sockets fo the balanced line driver. Then two pairs of balanced cables are connected to the two pairs of balanced cables to the two amps. Its a little work to set up and will cost a bit extra because you'll need two extra pairs of balanced cables and a balanced line driver - which must be of the active variety (will be plugged in to a power socket) i.e. passive will not add sufficient gain (you don't need hi-filutin' cables and line driver, just soundly made professional quality) . The results are well worth it. Most speakers benefit considerably from bi-amping, even if they sound really good to begin with. There will be less strain to the sound and there will be a lot more of it. The soundstage will grow considerably. Problem is, with most speakers, so much amplifier power gets sucked up in the impedences of crossover networks.
By the way, the Carver C4000T is a smashing preamp especially given the price it can be had for..

Most everything you said is way over my head,It has only been in the last year that I have even owned seperate components,it used to be an Onkyo receiver and some Cerwin Vegas.One of the reasons I joined this forum was to ask my newbie questions,I appreciate your input but your talking brain surgery to a brick layer at this point.

[E-Stat]

...could it damage anything.

Nope. Worst case is you may not have enough gain to drive both amps or as Feanor indicated the impedance drop could roll off the top a tad. Give it a whirl and see how it sounds.

I did that for a while when I used powered subs with a former set of speakers.

rw

[O'Shag]

Don't worry Scott - you'll get there.

[Scott W]

My biggest concern was that I might damage something,When I first got my Maggie SMGs,I was driving them with a Yamaha M-70 which says 8-16 ohms by the speaker connections but 4-16 in the instruction mamual,I dozed off in my chair one day and woke up a few hours later to what sounded like a tiny crackling boom box,Thought for sure I had ruined the amp but everthing still works fine,I'm just not using that amp for those speakers anymore.I have to admit that I am impulsive buying gear sometimes(you should see my basemnt,looks like a used audio gear store) and I am buying a Yamaha PD 2500 power amp later today,I didn't realize that this is a professional amp before commiting to buy,I was impressed by the 360wpc @ 4ohm rating,To the best of my knowlege I believe professional amps like this are used for DJ,PA etc???.So I hope that it won't be a step backward from the Hafler 9290 I am using now.I guess if nothing else I could use it to drive some subs.