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I want to stack my OLAs (Advents), would appreciate some guidance

OP Music

OP Music

Active Member
Hey guys, I have two pairs of Original Large Advents (utility cabs) that I would like to power with my Marantz 2325, I just want to make sure I'm doing this right. From most everything I've read, there seems to be a consensus that powering the Advents in parallel is the way to go. Will my Marantz be able to handle the low impedances of the Advents when stacked and wired in parallel?
 
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There is only one way to find out. I once had a Marantz 2245b that had no problem driving a 4 ohm load. I would think that the 2325 would have no issues doing the same.
 
Stack the speakers so that the tweeters are next to each other (top one upside down). This will give you a D'appoluto (spelling?) configuration (mostly) and remove any symmetry issues with the offset tweeter (not being left and right had pairs).

'ner
 
All this concern for 4Ω is gonna kill my amp. I have never worried about that but some say there are units out there that can't drive that load. I don't know what those are.

9" to milkcrate height stands, jumper from + to + and - to - on the speakers and flip over the top one like 'ner says and hook up the main speaker wire. Enjoy it, really is a nice speaker system. Way more than a single pair.
Or you can run separate speaker wires to each speaker and use the main and remote (A+B, Spk 1 Spk2 or whatever it is on the 2325) to play both sets so you can listen to one pair at a time. I have never done this but electrically it is the same as using the jumper.
 
Before my Nikko came to live with me, I ran a 2325 with stacked OLA's for quite awhile w/o a problem.

If you go for high volume, you might want to check the heat coming out of the Marantz from time to time. I'd take it easy on adding any bass boost (in my room, my OLA's never needed it with the 2325, in fact I actually found myself turning the bass down a couple of notches with some music).

Good luck to ya. I miss my 2325 - darn nice receiver you have there!
 
If you have spare receivers or integrated amps, give them each their own amp. This guarantees the impedance issue won't happen and you have more control over the volume separately.
 
KingBubba said:
If you have spare receivers or integrated amps, give them each their own amp. This guarantees the impedance issue won't happen and you have more control over the volume separately.
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Why do you say this. I think it perpetuates the idea that there isn't anything out there that can run a 4Ω load, when in fact there are so many that will that I don't concern myself with thinking a unit won't run that load. 4Ω speakers have been a choice since about the time they started making speakers and it seems most manufacturers knew this.

We see some specs that don't mention the 4Ω rating and folks assume that means it can't when in many cases the info printed on the back of the unit specifies that the unit can in fact run a four ohm load as a single speaker or as a pair of 8s in parallel using the speaker switch and running two pair.

and then we get to the doomsayers talking about the lower impedance being the death of the rig. Sure it requires more current but big damn deal the unit was built with components to supply that demand. Not picking on you there King but really why do folks get so concerned about it when a simple investigation for each unit will confirm that it can indeed run a pair of AR3a speakers at 4Ω or any number of other loads. Unless you get that rare instance with a low quality unit that is not designed to play normal speakers and says avoid 4 ohm loads.

Its gear, its old, it should be able to put out!!! and if it can't and prefers to be retired, let it put out smoke and I'll retire it. Until then, get em hot running em. The integrated amp I just returned to its owner runs very hot, a couple hundred degrees. As designed. No big deal. Crank it up.
 
ranch 22b said:
Before my Nikko came to live with me, I ran a 2325 with stacked OLA's for quite awhile w/o a problem
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Just curious what Nikko you are using. I just picked up a second set of NLA's to pair with my Alpha/Beta/Gamma II components. I've been dreaming of a second Alpha II, so each pair would have their own amp. I've read that Advents like power and two Alphas could certainly provide that!
 
Blue Shadow said:
Why do you say this. I think it perpetuates the idea that there isn't anything out there that can run a 4Ω load, when in fact there are so many that will that I don't concern myself with thinking a unit won't run that load. 4Ω speakers have been a choice since about the time they started making speakers and it seems most manufacturers knew this.

We see some specs that don't mention the 4Ω rating and folks assume that means it can't when in many cases the info printed on the back of the unit specifies that the unit can in fact run a four ohm load as a single speaker or as a pair of 8s in parallel using the speaker switch and running two pair.

and then we get to the doomsayers talking about the lower impedance being the death of the rig. Sure it requires more current but big damn deal the unit was built with components to supply that demand. Not picking on you there King but really why do folks get so concerned about it when a simple investigation for each unit will confirm that it can indeed run a pair of AR3a speakers at 4Ω or any number of other loads. Unless you get that rare instance with a low quality unit that is not designed to play normal speakers and says avoid 4 ohm loads.

Its gear, its old, it should be able to put out!!! and if it can't and prefers to be retired, let it put out smoke and I'll retire it. Until then, get em hot running em. The integrated amp I just returned to its owner runs very hot, a couple hundred degrees. As designed. No big deal. Crank it up.
Click to expand...

I was using a Mac 4100 receiver to drive a pair of AR 3a's, and a pair of AR3's, stacked. No problems, as that receiver has the capability to drive up to 3 pairs of 4 ohm speakers simultaneously. But I decided to experiment with running an additional amp(Adcom GFA 5400) for one channel, and the Mac for one channel, with a tube pre tying it all together(I've also tried the 5400 driving both pairs, and that worked to). Believe it or not, the sound improved. Better tonality, better separation, better soundstage. Could it be that lightening up the stress on the Mac helped? Who knows? But I would have to agree that if you have the additional hardware around, why not at least experiment? Can't hurt.
 
Big honkin' receiver with paralleled output devices. They don't even address speaker impedance in the manual, but I wouldn't expect a bit of trouble if the unit is in good shape to begin with. Just put your hand on top if you're running loud for long to be sure it isn't getting too hot. OTOH, if it's not in good shape, dried out thermal grease and questionable bias and protection, then all bets are off.
 
I have stacked NLA's powered by a Sony 100 wpc stereo amp from the mid 80's. Internally A plus B option outs are wired in series. I follow the Sony recommendation.
IMO, depends on how hard you drive them.
 
Back in '77 I bought two pair to stack along with a 65 watt Pioneer integrated, after listening to the Stacked Advent demo at several stereo shops. Many of them were promoting the idea. They sold a lot of them, mated with various Pioneer, Kenwood, Marantz receivers with no mention or discussion of impedance ratings...... I wonder how many of those receivers were returned because they failed? Very, very few is my guess. Nowadays, it seems the advice is to "proceed with caution" when stacking 8 ohm speakers.
 
Generally speaking, if an amp or receiver has 2 sets of outputs for speakers, the designer anticipated that it would be more then likely that 2 sets of 8 ohm speakers would be driven at the same time. If both (or one) set of speakers were 4 ohms, that would be a different story.

Decreasing the speaker load increases the amplifier power, and while that isn't bad, it can put a tax on the amps power supply that drives the output devices, and if that happens, puts the output devices into the proverbial "clipping" mode, which sends DC to the speakers and death to the voice coils if continued at high volumes.
 
Regarding the stress of high current on the 2325, the unit is probably 40 years old and we, at this point, don't know its history. I do know that my G6000, which is in about the same wattage range as the 2325, was fine with an 8 ohm load, but a 4 ohm load caused it to go into protection, if I wanted to crank it up. In addition, the amount of heat generated with a 4 ohm load was increased. Heat does kill these old units all the time. I stand by my suggestion.
 
ConradH said:
Big honkin' receiver with paralleled output devices. They don't even address speaker impedance in the manual, but I wouldn't expect a bit of trouble if the unit is in good shape to begin with. Just put your hand on top if you're running loud for long to be sure it isn't getting too hot. OTOH, if it's not in good shape, dried out thermal grease and questionable bias and protection, then all bets are off.
Click to expand...

KingBubba said:
Regarding the stress of high current on the 2325, the unit is probably 40 years old and we, at this point, don't know its history. I do know that my G6000, which is in about the same wattage range as the 2325, was fine with an 8 ohm load, but a 4 ohm load caused it to go into protection, if I wanted to crank it up. In addition, the amount of heat generated with a 4 ohm load was increased. Heat does kill these old units all the time. I stand by my suggestion.
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Being protective of an old worn out tired receiver is doing it a dis-service. It is not performing as it should and needs some work. Sound quality could be compromised or it may just be the protection circuits but whatever if the unit goes into protection driving a 4Ω load, it ain't right. Sitting back and proclaiming it the greatest sound ever because it is vintage, cheap and hasn't been brought back to spec a false proclamation. Get the unit serviced so you don't need to use two volume controls and guess how to set them to get Stacked Advents to play properly. One very good reason to go with a power amp instead of a receiver but that is for another discussion. Rock on with Stacked Advents. I really need to hear these again, one of the better speaker systems I had back in the day.
 
Blue Shadow said:
jumper from + to + and - to - on the speakers and flip over the top one like 'ner says and hook up the main speaker wire.
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I couldn't find any jumper cables long enough (on the internet) to do the job. Also, I think my speaker wire is too fat of a gauge to simply put jumpers on them. Any suggestions? The speaker terminal connectors don't seem to be the easiest things to connect two wires to.
 
Using the A and B speaker outputs on the Marantz would be the way to go. No problem with two sets of 8 ohm speakers like the large Advents. Ran my stacked sets of New Large Advents with a Pioneer SX-1010 and SX-1250 with no problems. Now stacking a pair of AR3a speakers is a different story. That load can dip under 2 ohms. Thought about using a pro amp like a Crown XLS2502, but wound up with two Adcom GAF 555II's.
 
I used the word jumper as a verb. I guess I should have said jump. Speaker wire is fine to go from top to bottom, same wire going from one back to the amp.

You can use crimp-on connectors. You can simply strip a section of wire a couple feet from the end and wrap it around the Advent terminal and then go to the other speaker. I probably just used bare wire, probably something thicker than 18 gauge and wrapped one wire on and then started at least 90° away and wrapped the other so that I could tighten the thumb nuts.
 
So if you wanted to stack The Smaller Advent Speaker, which is nominal 4 ohms, would you connect them in series so that they look like an 8 ohm load to the amp?
 
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