Running two pair of OLA'S together

[Andrew055]

I have a Technics SA 500 receiver that is currently powering one pair of OLA'S. I just acquired a pair of NLA's  and would like to run them together. My question is whether I should just run one pair on the main and one pair on the remote at the same time or run then in parallel or serial and if so how? I was just concerned about whether my receiver which is rated at 55 watts into 8 ohms would be enough?

[JKent]

I think it should be fine as long as you are not filling a stadium. That's a real nice vintage receiver. Panasonic makes quality electronics and even though the Technics line is mass-market they're built well.

According to the owner's manual (available free, along with other lit here: https://www.hifiengine.com/manual_library/technics/sa-500.shtml) if you run Main + Remote at the same time 8ohm speakers are fine. If you run 4 ohm speakers you can only do Main OR Remote.

Kent

[Andrew055]

Are both the OLA's and NLA's both rated at 8 0hms?

[JKent]

Look at the speaker connections on the back. One terminal is marked "0" and the other "8 Ohms" (on the OLA at least. I've never seen the NLA but I'm sure they're the same).

[Norman Nicolai]

I had a set of OLA’s and NLA’s at one time not too long ago. They were both rated at 8 ohms. If your speakers are truly OLA’s and NLA’s, and no one has replaced any of the original drivers or fooled around with the internal wiring, they should both be rated at 8 ohms. I ran mine off the main and remote speaker terminals of my my HK3490 receiver which was rated at 110 WPC and had no problem.

I think you may like the combination. To my ears, the OLA’s high frequencies were just a bit rolled off, and the NLA’s were a just a tad too bright. In combination they worked well together. You can fool around with the 3 position switch on the back of each speaker to tune them to your taste. Just in case you are not familiar with it, the classic “stacked Advent” combo has the bottom speaker in a traditional orientation with the tweeter on top. The stacked 2nd speaker had the tweeter on the bottom and the woofer on top. I think the idea was for speaker imaging you wanted both tweeters closer together.

I’ve since gotten rid of the NLA’s. I was running out of room in my basement and had to make some choices. I think the OLA’s sounded just a bit better for the jazz and classical that I listen to more frequently.

Have fun and let us know how you like them!

[Doug G.]

The thing to remember with solid state amplifiers is, no matter if they have main and remote terminals or not, the speakers are being driven from the same output transistors. There are not separate outputs for the main and remotes. There are merely switching schemes to turn one or both pairs on or off.

If an amplifier is capable of driving 4 ohm loads, the switches will typically be wired so the speakers are in parallel with both on. If an amplifier is not designed to drive a 4 ohm load, the switches will be wired so the speakers are in series with both of them on.

The way to check is to connect a pair of speakers to, say, the main terminals and turn them on. While they are playing, with nothing connected to the remote terminals, turn the switch for the remote speakers on. If the main speakers keep playing, the switches are wired in parallel. If the main speakers stop playing, the switches are wired in series.

A pair of Advents dip pretty low in impedance at some frequencies and are much better driven by a separate amplifier for each pair, even though they are rated at 8 ohms. This is true of most setups. In spite of what manufacturers advertise, a 4 ohm load stresses an amplifier quite a bit more than an 8 ohm load. More current flowing through the output devices produces more heat which, of course, is the enemy of longevity.

I have four Advent stacks in my quad system and each pair is driven by its own stereo amplifier - four stereo amplifiers or, in my case right now, two quad amplifiers.

 

Doug

[Norman Nicolai]

After reading the post by Doug G. I did some subsequent reading and found out that many people thought that NLA’s should not have been rated at 8 ohms, that a 4 ohm rating would probably been more accurate. Bottom line: NLA’s are not a good candidate for Advent stacking.

I was probably pretty lucky mixing my OLA’s and NLA’s as stacked Advents. The receiver I was using, the HK3490, was advertised as a “high current” amplifier. High current amps are supposedly better at handling low impedance loads than most other amps. At least that’s what I have read. I don’t know if that’s the reason I did not have a problem. Maybe I was just lucky. But if I were you, probably not a good idea to use NLA’s in a stacked Advent set-up.
 

 

[Doug G.]

Usually, a problem will not present if the speakers are driven at reasonable levels which is why most manufacturers claim the ability of their amps to drive 4 ohm loads. It's just something to be aware of and I believe, if memory serves me (a danger, these days), Advents, whether original or New, dip down near two ohms in some spots on the impedance curve. Pete would know better than me.

Doug

[Martin]

Pay attention to what Doug G. says, above, because he is correct.

[Andrew055]

Thanks for all the good advice. I decided it wasn't worth it in the long run to risk damage so I will leave well enough alone. 

[Frank Braswell]

Hi, I'm new to the group and thank's for allowing me to join. I'm a long time advent speaker fan. I have been fortunate enough to listen to the vast majority of analog equipment over the past 40 yrs. and that includes the majority if not all speaker brands. I have owned my fare share of analog equipment and speakers. I haven't owned any advents since the late 70's early 80's. recently I picked up a pair of OLA's with the beveled cabinets and restored them cosmetically the drivers are oem and needed nothing, the previous owner had refoamed the woofers correctly. they sound just like I remember not complicated fairly neutral and warm with good bass. not many speakers can do this at this price. I pick up a second pair of NLA's with the walnut bullnose cabinets. I personally like the OLA's better but they are both great sounding speakers. for a two way speaker they kick a**. I run the pair stacked powered by a JVC jrs-501 in my mancave (garage). sometimes I play them fairly loud and they bring a smile to anyone who hears them even my wife. she's a klipsch fan. haven't had any issues with impedance differences. the bass response is impressive when you stack them. i'll just leave them alone maybe hard wire them to eliminate the connectors. my only question for the folks in the know is what is the purpose for the masonite around the woofers and tweeters on the OLA's

[Doug G.]

Welcome, Frank.

My main system is quadraphonic with four Advent stacks and it sounds wonderful.

Upstairs in my train room, I have another system with just  a single pair of Advents. Last night, I was playing an LP of big band hits from the 30's - 40's by Enoch Light's band and it was astounding how good it sounded. That's the thing about Advents. If a source is good,Advents really bring that out.

Doug

[Doug G.]

Oh, and as to your Masonite question, the Masonite rings on the woofers act as spacers to allow a 10" cone to be mounted in the 12" frame. Kloss needed the frame to be deeper than normal so the cone excursion could be great enough to take full advantage of low frequency reproduction and so the voice coil former wouldn't bottom out at high signal levels. At the time, there were no 10" frames deep enough to accommodate that aspect and so, he used a 12" frame and the Masonite rings to span the space.

The Masonite on the tweeters just acts as a mounting for the cone/dome.

Doug

[blanddawg625]

Hello, everyone. I currently have a pair of NLAs with New Advent/1s on top. And I have noticed all the talk of impedance dips. However, these dips are so quick(usually 1/100th or 1/10th of a second), that receivers or amps capable of handling 4 ohms are fine. The way to go is with a separate power amplifier if you really like it loud. Mine are run by a Crown PS200 which is an A+A/B+B class and is conservatively rated at 170 into 4 ohms. High current is what makes most separates safer at lower impedances.

[jessiAV]

You are quite correct that high current amplifiers can drive lower impedance loads reasonably well. Reproducing dynamic music means that there will be short-duration current demands from your amplifier, which typically last much less than 1/4 of a second. However, a speaker's impedance/reactance characteristics remain largely predictable.

[Markkb]

“Bottom line: NLA’s are not a good candidate for Advent stacking.”

I’ve been running a double stack of NLAs for years. A person needs to understand their amplifier. It needs to be capable of a 4 ohm load. As reported, stacked Advents can dip to 2 ohms. If the amp is capable of an 4 ohm load, and after deciding to run them, feel the amplifier for heat. If it’s too hot then turn down the volume or don’t run a stack. 
There’s a great write-up/analysis by Pete B on stacked advents, ( I couldn’t find it) but I believe there is a suggestion to run them with the rear switch set on decrease to lessen the 2 ohm impact. 

I’d appreciate if someone can link that.