Speaker connection

[Clansman1968]

Hi I have a pioneer cassette deck connected to pioneer amp I also have a pioneer 8 track player/ recorder with built in amp what's the best method of connecting them to the same speakers .

[Simon Gittins]

I would think a speaker switch is the best method.

Whatever method you use, you need to make sure that both amplifier outputs don't get connected togetether.

[Hartley118]

A silent amplifier output looks like short circuit to another amplifier. Switching is the solution.

Martin

[Radio Wrangler]

Also, make sure to always bring the volume right down to zero before operating any speaker switch. Switching speakers while playing creates transients fed back into the output of amplifiers and risks blowing up output transistors.

This is a good precaution even with amplifiers having their own speaker switches built-in. They often don't have enough protection for them to be operated risk-free.

If one or both your amplifiers have output switches, then you can't use them and still be able to arrange an interlock to prevent amplifier-driving-amplifier trouble.

In general, some amplifiers have bridge outputs, and even those with one output pole at ground might give you an earth loop if the cold ends aren't also switched and kept separate. If it's a car 8-track player with moderate or more output, then it is very probably a bridge output with both poles to each speaker being 'hot' and must be kept separate.

David

[Clansman1968]

Thanks for the advice guys.

[Kentode]

What a coincidence! I was looking for a pair of bookshelf speakers in storage and found this. I was just about to put it in the "for sale" thread, but you can have first refusal here if you want.

Never been used, l bought it eight years ago for a "project". If l had a pound for every project I never finished...

No obligation.

£12 + p&p.

[Simon Gittins]

You will have to use the switch in the opposite way to the labels of course as it's intended to connect one amplifier to several speakers. Connect the "AMPLIFIER" terminals to the speakers and use the "SPEAKERS PAIR 1" and "SPEAKERS PAIR 2" terminals for the amplifier outputs.
You will also need to check the exact behavior of the switch with a meter in order to heed the important advice in Post 4.

[McMurdo]

I think that switch box might lead to an accident!

[dave walsh]

I have some eight track player/recorder gear [non working] and probably not as good as the OP's Unit. I've never considered two systems shairing the same speakers before, only the more usual separate sources via the amp and switched inputs with one set of speakers but clearly it can be done. I presume the difficulty is a lack of a separate signal output from the 8 Track machine?

With reference to the appropriate warnings about the speaker switching I wouldn't be that confident about not making a mistake myself but that's just me perhaps? I'm guessing that the Pioneer/Cassette Amp combination might be a bit better quality than the 8 [narrower] Tracks Player/Recorder, so a dedicated pair of speakers, for the latter, might not need to be very expensive. Given that the 8 Track system was [I believe] originally designed as a music source for American vehicles, a pair of redundant car speakers might be highly appropriate Of course if the OP only wants to play both set ups through the one spkr pair [for direct comparison perhaps] or might be short of space, it's a different matter.

Dave W

[Please don't use my vehicle comment to talk about cars-it's not allowed as it creates major problems for the Mods!]

I think Kevin just pipped me at the post there but was much more succinct!

[Vintage Engr]

I'd just like to endorse what others have said about speaker switch boxes....
I recently repaired a really nice Sansui amplifier for someone. The original fault was that the output transistors on one channel had gone s/c.

I replaced all output transistors, as the originals were NLA, & I'm a perfectionist. So I substituted better types & re-biased. All was perfect, the amplifier was soak tested for two days, & returned to its owner with a warning & some discussion about checking the speaker cables etc. I was assured that 'nothing had changed' with the customer's installation, & that 'anyway, there's another amplifier also feeding the same speakers, & that's o.k.' - It's always worked o.k.

Two days later, a phone call 'I don't know what I've done but it doesn't work'.
After questioning the owner, it seems that a couple of switch-boxes had been added.
I decided to make it a field call.

You don't want to know, - you do?

So there's the nice Sansui, fed from a variety of traditional sources, the speaker output of the amp then fed to an array of switches. The Sansui, 30W /channel. The other source, a CD jukebox, 150W/channel. three sets of speakers, 8ohm, 4ohm, & 6 ohm.... Sansui rated min load 8ohms. Further switch selector: (The original 8ohm 30W speakers can be connected to another source)

The switch selector functions:1 room, 2nd room/ 3rd room, & all /any speakers on at the same time, or not. The speaker selector switch appeared to be...'make-before-break'
For fun, as I had taken an impedance meter with me I checked the various options at 1KHz.... around 1.9 ohms, & almost any variant up to 8 ohms.

'Nuff said, - I replaced the output transistors, (this time it was a different channel, who cares?) With a stern warning to just use the speakers one pair at a time, & only connected to one amplifier, I left, having been further paid for my efforts.

The moral of the story, I'll leave that to you to decide! Switch boxes? Only if you know what you are doing.

David.

[Vintage Engr]

I forgot to mention.. The customer likes the wick turned up high. It was certainly too much for me, loud, really loud. I shall take ear-defenders if I go back!

[Nickthedentist]

I would be tempted to use one of those transformers that are sold in car audio places to connect the speaker outputs of the eight track player to a spare input on the amplifier.
https://amzn.eu/d/0FcsvTb

[Kentode]

The house appears to have voted, overwhelmingly, against the use of a switch box in this instance.

I withdraw my offer.

[vu2nan-nandu]

Two DPDT switches are required.

Here's the schematic.



Nandu.

[dave walsh]

You've confused me there at post #13 Ken If the OP decided to get a second pair of speakers in the end, the switch box issue would be redundant. You made a good offer The very extreme example described by Vintage Engineer in posts #10 and #11 is possibly illustrative of someone who's arrogance is only exceeded by ignorance and the inability to listen. I was completely unsurprised to "hear" that he likes to turn up the volume. I've got a nephew like that- not alone in his approach to the world. He's very nice on a one to one basis but hopeless in terms of reliability. Nothing is ever his fault!

Dave W

[ben]

You say you have a cassette deck, amp and 8 track recorder.
You don't say what models they are. This would enable us to check the inputs and outputs of each unit.

I would imagine the cassette and 8 track have line in and outputs. Or at least, a headphone output.

I would connect as follows:
Pioneer amp to speakers.
Cassette line out to Pioneer amp 'tape' input
Pioneer amp 'tape' rec output to either cassette or 8 track line input (depending on which you want to record onto)
8 track line or headphone output to pioneer amp aux input.

Hope that helps.

[Kentode]

Originally Posted by Clansman1968

Thanks for the advice guys.

You're welcome...