Help with Tri amp hookup

[Markep]

I have moved to NC from NJ, and in the process, I am trying to transplant my Linn LK85, and Linn AV5140 setup. I didn't pay sufficient attention when I unhooked thesystem in NJ, and now I am struggling to figure out what to do. I understand how to hook up the speakers with the 3 separate power amps, but how do I hook the power amps up to a pre-amp/receiver ?

Thanks for any help.

[dingus]

unless the the pre-amp/receiver has 3 sets of outputs, you must have been using a signal splitter.

[Markep]

I don't remember that the pre-amp had 3 sets of outputs, so I guess there was a splitter. Is this a fairly standard type of item that is easy to buy ?

[dingus]

if you dont have everything unpacked yet, then i would do that first and then see if you can find all the pieces and get everything connected the way it was before.

splitters are readily available, but i've only seen rca's that do a 1-to-2 split (something like this),
http://columbiaisa.50webs.com/cable_splitter_rca.jpg

....so i'm not sure how you would have had a 3rd amp incorporated into the mix.

[E-Stat]

and now I am struggling to figure out what to do.

I see two possibilities:

1. You have tri-amped speakers using an active crossover to drive three separate drivers in your pair of speakers. Preamp drives crossover which has separate outputs for bass amp, midrange amp and treble amp.

2. You have three separate amplifiers for a multichannel system. Your AV preamp/receiver has separate outputs for left, right, center, rear left, rear right (also back left and back right if 7.1). If a receiver, there may be jumpers to the internal amplifiers in place.

rw

[Markep]

Linn AV 5140 speakers have an optional card ,which I have, that makes the speakers "Aktiv". The cards in the speakers are matched with corresponding cards in each of the three amps, and thus one amp each matches up with the tweeters, mids and woofers. The cards bypass the speakers normal crossovers. Unfortunately, I left behind the prior pre-amp/receiver, as part of my house sale, so I have now ended up with a system I don't know how to get to work again.

Hopefully someboody can point me in the right direction.

[E-Stat]

The cards in the speakers are matched with corresponding cards in each of the three amps, and thus one amp each matches up with the tweeters, mids and woofers.
Ok, so that is the first scenario. Your active crossover is the series of cards. Each amp will need output from the preamp and the speaker leads from each amp will go into the appropriate set of terminals in the back of the speaker. As dingus suggested, you can use RCA splitters to provide separate feeds for each amp. If you're unsure as to which amp drives which driver, you can always hook them up one at a time to get the right frequency range match.

Good luck!

rw

[Markep]

Thanks E stat. The Amps are marked, so I do know which one goes with each set of drivers. With respect to the splitters, I will need 2 of them, splitting the split signal again and leaving one side of the second splitter open. Does it matter which of the amps gets the "first split" , so to speak, and which gets the last ?

[dingus]

i'm thinking that if you are handy with a soldering iron, a diy solution would be better than splitting the signal twice. then again, i've been told by more than one knowledgeable and experienced person that splitting the signal once (1-to-2) does not degrade the signal, so splitting it twice may not be an issue.

[E-Stat]

Does it matter which of the amps gets the "first split" , so to speak, and which gets the last ?
No, but there is a relevant consideration when using this approach. The preamp's output sees the combined input impedance of the three amplifiers which lowers the value. You need to be careful about choosing a preamp which can handle such a load.

rw

[Markep]

Hmm. The preamp that I did have driving the 3 Linn amps was a Rotel surround sound preamp. I left the Rotel with the house to service the surround, and I have a 15 year old Luxman pre amp that I am thinking about using with the Linns, but I don't want to hook it up and find out the hard way if it cant handle the load. How can I tell if the pre amp can handle the load ? If I buy a new pre amp, is there any particular spec I could look for to tell what it can handle ?

[E-Stat]

How can I tell if the pre amp can handle the load ? If I buy a new pre amp, is there any particular spec I could look for to tell what it can handle ?
Ideally, you want a very low output impedance to drive a low impedance amplifier load (say 20k ohms). It's not something that would damage the older unit - the sound would lose some dynamics and roll off the top a bit.

rw

[Markep]

I found a review of my Luxman TP-117 pre amp, which I have linked below, but no mention is made of its output impedance. If you don't mind, please take a look at the review and see if I missed it somewhere.

Thanks for all the help, I may yet get this stuff running again !

http://www.fmtunerinfo.com/TP-117reviewSR.pdf

[Markep]

One other thought, I also have a Linn LK1 pre amp, about 24 years old, but I am using it in a different room and it works great. I do know that its output impedance is 71.5 ohms, would this be a good match for the tri-amp system ?

Edit - I just looked up the input impedance for the LK-85 power amps, and they are 10k ohms.

[E-Stat]

If you don't mind, please take a look at the review and see if I missed it somewhere.
No, you didn't miss it in the test. The other factor that conspires against you is the need for relatively long cables which increases the capacitance. Your situation is almost like that of a passive arrangement.

rw