Powering a vintage Polk Audio Monitor HT system with vintage amps.

pMac76

Hi all,

I have a few newbie questions to ask that a search hasn't found. Apologies if they are repeat questions.
I've just decided on Polk Audio Monitor 7's for my main speakers after hearing them at a friends place. I love the idea of recycling vintage gear for a HT system.
I'd like to get a 7.1 system with my Oppo BDP-83 player outputting to a series of vintage stereo amps.

My first question is; do the speakers need to be powered by equal wattage or can the fronts be powered by a bigger amplifier compared to the surrounds?

Secondly, how would you go about amplifying a subwoofer and centre speaker(s) in this type of setup.

Lastly, how do you setup a vintage system sonically? I mean is there rules or calibration tools you can use to get the right volume levels, delays from different amplifiers?

Thanks for any help you can give me or pointing me in the right direction.

Cheers,
Peter

westmassguy

I have a HT system using all vintage Polks. My 2As required more current than my AVR could safely provide, so an external amp was required. The remaining Center, Surrounds and Rears are powered directly from the AVR.

pMac76

Thanks for your input westmassguy,

I guess I was wanting to avoid using an AVR and just use my oppo player with vintage 70's amplifiers if possible?
I just love the sound from my current vintage stuff so much more then my HT setup. I also like the idea of using/recycling vintage equipment in general. Now, I'm not trying to be cheap about it, my initial research shows me this would cost me 2 or 3 times as much as a reasonable AVR or the cost as much as good AVR ($2000AUD).
Sorry I'm not trying to discount that option, but rather trying to explain my reasoning for the idea.

Thanks again

tonyb

DSkip wrote: »

The oppos don't sound great as preamps. Vintage amps will also require work soon if they haven't been checked recently. I'd be scared to have that many vintage amps that I rely on.

Good points and all valid ones to consider. More to the point, you can do as you want, setup the Oppo to do all the processing, but I don't think it would sound all that good. Also the amps, if you have a 7.1 speaker system, that's 8 rca cables additional that need to go to 7 channels worth of amplifiers and a subwoofer. Another route is to get a receiver with pre-outs, let the receivers built in amplification handle everything but the 2 front left and right speakers. Just add one vintage amp for the front left and right speakers. You still get the vintage sound, plus don't have to buy all those RCA cables.

Does the OPPO 83 even decode the most current surround formats ? I'm not sure that's why I'm asking. Just out of curiosity, I know you like the vintage Polk sound but what vintage amps are you talkin'....exactly ?

pMac76

Thanks for the warning guys, I guess I'll have to adapt my idea to at least include a pre-amp as well as the oppo player.

For the record I was fully intending on servicing the amplifiers or buying from vintage audio shops that sell serviced units with warranty.
The amplifiers I had in mind were something like a Marantz 140 power amp for the fronts (2ch x 75w), and something like a Marantz 4270 quadraphonic amplifier for the surrounds and backs(4ch x 25w). Hadnt figured out the centre(s), maybe another stereo amplifier, not sure for the sub.
I'm also not sure if a quadraphonic amp could power two sets of surrounds?

A lot of affort for sure, but I was after something different sounding, a display cabinet full of vintage amps to show off and ya, bragging rights about it all.

Also tonyb, the oppo doesn't have the latest surround formats , but I'm not sure that bothers me.

Nightfall

DSkip wrote: »

I'd be scared to have that many vintage amps that I rely on.

This is my thoughts too. Don't be fooled by "serviced". This doesn't mean they replaced everything, only that they replaced what was obviously wrong. I truly love my Yamaha CA-1010 but it can be aggravating. A channel goes out, I get it fixed. 6 months later a channel goes out, I get it fixed. It's currently sitting unused because the left channel is out... Unlike a pair of speakers there is an awful lot that can go wrong:

tonyb

Yep, vintage amps are going to need servicing, and probably on a regular basis, so be prepared for those costs. You would need a HT pre amp, not a 2 channel pre amp, which will cost as much if not more than a receiver would.

I don't think you'd find anyone here who doesn't love a solid vintage system.....for music, HT is another animal.

boston1450

I despise vintage

westmassguy

A good AVR, with "Pure Direct" or similar, will bypass all the built-in signal processing. Use the analog outputs on your Oppo and it's internal DACs for 2 channel. Use the Optical or Coaxial output from your Oppo for Home Theater. That's the easiest and least expensive way to do what you want to do. Add an external amp for the fronts.
Even mid-fi AVRs have built-in calibration for Home Theater, which you will definitely need. A powered subwoofer is also needed.

Schurkey

"Home Theater" will typically need a powerful center channel, powerful left and right front speakers, while the side and rear speakers can be significantly smaller and less-powerful. A subwoofer--internally-powered or not--is practically required; especially if the main L and R speakers don't have deep bass.

Multi-channel music will typically require all speakers and channels to be equal. Multi-channel music is MUCH more demanding than multi-channel movies everywhere except maybe the subwoofer. Oh, sure, you can run multi-channel music through a home-theater system, it's acceptable but it's not optimum. I know of NOBODY who has a proper multi-channel music system.

You're going to need considerable processing of the various channels--time delay to account for speaker position, subwoofer crossover level(s), lip-synch delay to allow for the time required for video processing, volume adjustment(s) to promote channel balance, and of course the actual Dolby or DTS decoding scheme(s) plus D/A conversion...the list goes on and on. If the Oppo has this sort of processing built-in...fine...I'd be surprised.

You need a proper multi-channel preamp/processor, (pre/pro) then you would connect the outputs to the (line-level) inputs of several stereo (or multi-channel) receivers, integrated amps, or power amps. Clearly, power amps would be preferred to integrated amps, which are preferred to receivers.

A quality pre/pro could cost as little as ~$400 on the used market. "Vintage" stereo receivers can sometimes be had for the carrying; if you rescue them from the curb on "cleanup week". As said, you can expect to pay more to have the "vintage" equipment refurbished than the purchase price will cost you.

pMac76

Thanks everyone for taking the time to explain what would be involved. For the moment I'll probably just start with an AVR and vintage stereo amplifier as tonyb suggested.
I still love the idea of adding more vintage amps at some stage, but I hadn't realized how fragil the vintage amplifiers are, nor what serviced actually means with amplifiers.

daddyjt

pMac76 wrote: »

Thanks everyone for taking the time to explain what would be involved. For the moment I'll probably just start with an AVR and vintage stereo amplifier as tonyb suggested.
I still love the idea of adding more vintage amps at some stage, but I hadn't realized how fragil the vintage amplifiers are, nor what serviced actually means with amplifiers.

Don't be scared of vintage amplifiers. Amplifiers typically don't have many moving parts, and a properly serviced (All electrolytic capacitors replaced, power resistors checked, rail and bias voltages calibrated, dc offset checked, and power switch cleaned - as well as any needed repairs completed) vintage amplifier will give you 20+ years of trouble free service. In fact, I think you'll find most "vintage" amplifiers to be somewhat more robust than current (pun) offerings. However, that service is not cheap - expect to pay $200 ~ $400, depending on the amp, for a qualified individual to perform these tasks.