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Main and remote speakers not working together

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Bread

New Member
Day 1 newb here. I just set up an old Technics amp and connected some Sony speakers and a subwoofer to the 2 main and 2 remote speaker ports. I understand the intended use for these ports are for different rooms, and you wouldn't normally use both together, but I want to use them both. The issue is when I play from main or remote, the sub works fine. But when I try to play both at the same time, the sub stops working and only the speakers have sound. (Speakers and sub are all rated at 6 ohm impedance)

I've looked at some threads here and it seems like there is conflicting info. Some say they should work at the same time and some say the only way for this to work is to connect them in series (which I do not know how to do) or get another amp. Can someone explain why this wouldn't work and if there is a solution?
 
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Is it a powered (active) sub, or a passive (not powered) sub?
Are you going to be using them in one area or two?
How many main speakers are you using, 2 or 4?
 
are you saying you have the sub connected to both the main and remote terminals? you might not want to do that and only connect the sub to one speaker terminal, or ask those "some people" for a solution.
 
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Can you detail exactly what you have connected to what? e.g. speaker 1: + to red, - to black on amp's speaker A left connection. Do that with all speakers and the sub so we can figure this out. Also, giving the make and models of everything would be helpful.
 
just as an aside, two man speakers and the subwoofer, each at 6 ohms, presents a 2 ohm impedance to the amp. something to consider

This doesn't answer why the sub doesn't work, but I'm thinking it might be connected out of phase.
 
the skipper said:
are you saying you have the sub connected to both the main and remote terminals? you might not want to do that and only connect the sub to one speaker terminal, or ask those "some people" for a solution.
Click to expand...

I have connected the sub to the main and remote at separate times. Let me further clarify. On the amp there is room to connect 4 total speakers. 2 Main and 2 Remote. I've done testing so far with 2 speakers and a sub in all variations. When I connect the Sub and a speaker to the main and a speaker to the remote, Sub and speaker work fine when just Main is engaged, but when Main AND Remote are engaged, sub stops working and only the speakers works. When 2 speakers are connected to main and sub and connected to remote, everything works as expected when Main OR remote is engaged, but when both are engaged the sub stops working. In all variations, the result is the same.

I may need to brush up on my electrical knowledge, cause maybe the issue is with the impedance. As I mentioned speakers and sub rated at 6 ohms. On the back of the amp it has a rating of 8-16 ohms for both Main OR Remote and Main AND Remote.
 
goodolpg said:
Is it a powered (active) sub, or a passive (not powered) sub?
Are you going to be using them in one area or two?
How many main speakers are you using, 2 or 4?
Click to expand...
One area. The sub and speakers are passive.
I've tested with 2 speakers and a sub.
 
swechsler said:
Can you detail exactly what you have connected to what? e.g. speaker 1: + to red, - to black on amp's speaker A left connection. Do that with all speakers and the sub so we can figure this out. Also, giving the make and models of everything would be helpful.
Click to expand...
Does my reply to the Skipper answer your question about the connections?
Amp: Technics Stereo Integrated Amplifier SU-V77
Speakers: Sony Speaker System Model SS-MSP66SL
 
Bread said:
Does my reply to the Skipper answer your question about the connections?
Amp: Technics Stereo Integrated Amplifier SU-V77
Speakers: Sony Speaker System Model SS-MSP66SL
Click to expand...
Not really, still not clear. But I think the problem is related to the fact that it was common on Technics amps and receivers for them to put MAIN & REMOTE in series when you selected both of them. If you connect speakers to MAIN and leave remote disconnected, then select MAIN+REMOTE, do you hear anything? If not, it's because they are in series, and since there's nothing on the remote circuit, that means that the MAIN speakers are in series with nothing.

Looking at the back panel, I'm pretty sure this is the case. You'll note that it says minimum 8Ω for either one or two sets connected at once. If the speakers were connected in parallel when both were connected, this would yield a 4Ω load, so then it would also allow 4Ω when only one pair was connected. It's obvious that this amp is not suitable for low impedance speakers, which is why they use a series circuit. Therefore, I don't know if there is a solution that will work with this amp.

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Yeah, it would be more feasible if it was a powered sub.
I'm not sure if running the sub in series would be safe, plus you'd maybe only get one side (left or right) of the bass signal. Someone smarter than me would know.
 
From the service manual:

Screenshot_20211025-201014_Xodo Docs_1.jpg

It's a series connection. Not a good idea to use an amp like that with two pairs, when one is a sub. IMO, not a good idea to ever connect two pairs to an amp like that, unless you never use both pairs at once.
 
The subwoofer appears to me incompatible with the receiver you're using it with.

Seems it's intended to receive a summed mono, speaker level input. The receiver you're trying to use it with doesn't have that type of output/connectivity.
 
Passive subs used with left/right speakers that weren't designed to work together isn't recommended. The whole purpose of a subwoofer is to relieve the main speakers from reproducing low bass. With a passive sub, there's no way to match volume levels, no way to isolate the sub from the main speakers, and no way to cross the subs and mains at compatible frequencies. In addition, you're robbing amplifier power from the main speakers. Investigate the feasibility of incorporating a plate subwoofer amplifier into your system.

https://www.parts-express.com/Dayton-Audio-SPA250-250-Watt-Subwoofer-Amplifier-300-803
 
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Some passive subs have crossovers with high pass filters so the mains are isolated, so to speak, from the sub. However, that's not the case here.

It's a sub/speaker setuo from a HTiB. It's basically intended for use with active crossover/home theater receiver, but with a twist inasmuch as the receiver directly powers the sub with a summed mono power output rather than a summed mono line level output.

I'd suggest if money need be spent to make it work, that money be spent towards a different sub (and maybe speakers too) that's more directly compatible with the Technics, rather than IMO, good money after bad.

https://www.parts-express.com/Dayton-Audio-SUB-1000-10-100-Watt-Powered-Subwoofer-300-628 (~ $160)

Or $20 more for the 12" version.

Those don't have high pass filters but in many cases the HPF is a sub is only a 6dB/octave capacitor filter. Easily accomplished externally with "bass blockers".

Or search around Craigslist or whatever. There are alway some sorts of subs listed there.
 
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Yeah, that Technics can only handle an 8 ohm load so they wired the speakers in series. Not a very good amp to try to do what you are doing. Even just one pair of 6 ohm speakers will tax the amp.
 
Yup, depending your market subwoofers can be had for way less than new pricing.
I have the Dayton sub 1200, was very happy with it. Careful though with the spring clips if you wire to them. Large gauge wire might not fit or the clips might separate, unless they changed the design. I bought mine new years ago. No issues if you use the RCA's.
Picked up a "better" sub at garage sale, that's the only reason I'm not using it now.
 
coonmanx said:
Yeah, that Technics can only handle an 8 ohm load so they wired the speakers in series. Not a very good amp to try to do what you are doing. Even just one pair of 6 ohm speakers will tax the amp.
Click to expand...

Regardless, the main problem is not the receiver. The main problem is the subwoofer is just not compatible with the connectivity of the receiver.
 
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