How to make Sony SQR-8750 real SQ? + something else...

[CZmok]

Hello quadraphonicquad!

I'm the noob to vintage SQ sound, please don't beat me for stupid questions but I need little help.

1.) is that true, only way to reproduce SQ sound is to connect inputs to these red 4ch connectors and switch the amp to 4ch mode? (see pictures) Do I need some other equipment to reproduce 4ch sound for example from PC, maybe some sound cart which is able to generate 4.0 sound?

2.) Is somehow possible to use AUX (or phono1, phono2) input to reproduce 2x2 stereo (4 speakers) sound but with ability to control volume for each speaker independently? I just found way how to reproduce 2x2 stereo but I can control volume just for right or left NOT for front or back.

3.) About radio... What is the best way to connect modern FM antena (and which one?) to this amp? Now, I use only wire, but it is not so nice.

Thank You very much for discussion and hints.

CZmok

 

[par4ken]

That receiver would have an SQ decoder built in. Make sure it's set up for 4-channel and not bridged for 2-channel operation. Select your 2-channel source and press the SQ button,, to decode to 4-channel.

If you are using a separate decoder connect it's input to the 2-channel tape output, it's outputs can connect back to the amplifier as you have shown.

I don't know about the Sony but most manufactures switched stereo to the front speakers only, so to run stereo from both front and back amplifiers you might have to go from the tape output through a Y connector cable to supply front and back 4-channel inputs with the same signal.

Most vintage equipment was made for a 300 ohm balanced antenna, you can simply use a Matching Transformer 75 Ohm to 300 Ohm (Balun) to connect to the coaxial cable more commonly supplied with modern antennas. Finding a good FM antenna these days can be difficult. Many TV antennas are designed to cover the FM band as well, and should work OK.

 

[CZmok]

Thanks @par4ken. I tried configuration You mentioned (SQ switched, 4 chanel mode, 4 speakers in A, AUX input), but in this case just hum gets out from speakers. Might be a bug of amp?

 

[par4ken]

What does that Aux cable connect to? You need a stereo source to hear anything through the amp such as a CD player or computer sound card. The wire connected to the FM antenna terminal is on the ground side and won't function as an antenna that way. You could try attaching separate pieces of wire to the 300 ohm terminals and you might be able to pick up local stations.

 

[CZmok]

On the other site of AUX cable is smart phone connected to 3,5 mm jack. I gues it is able to reproduce stereo sound.

Soo, only way I'm able to reproduce sound from 4 speakers (2x2 stereo but without controling front or back speakers) is:

- amp switched to 2 chanel HI power mode in the back side of amp.
- 4 Speakers connected to A front and B front. Back speakers are disconected by deafault.
- Speaker selector is switched to A+B mode
- Switcher on the front side of amp is also switched to 2channel mode.
- Input Aux (or phono1 or phono2) is pressed.
- Any other settings from inputs aux, phono1 or phono2 is not able to reproduce sound from 4 speakers.

Any other idea how to reproduce true 2x2 stereo or full logic sound from my device? Many thanks to everbody.


About the antena. Acording the manual I believe I connected tha cabel right.. Actualy it does not have 75 ohm, bud it seems working somehow.. BUt I wont something nice, not just peace of cable...

 

[par4ken]

You can use all 4 output channels 2x2 as I said if you use two Y connector cables to combine front and back amplifier inputs together.

 

[CZmok]

thanks for You patience with me. So I have to use BLUE inputs instead of RED (see picture)?

 

[LuvMyQuad]

About the antena. Acording the manual I believe I connected tha cabel right.. Actualy it does not have 75 ohm, bud it seems working somehow.. BUt I wont something nice, not just peace of cable...

The antenna is not connected correctly, as both leads are connected to the ground side terminals. The connections you are using are for connecting a bare 75 coaxial cable, which is not the type of cable you have connected. With the 75 ohm cable as shown in the manual, the outer ground shield connects to the strap while the positive center connects to the single terminal to the right.

You will likely have better luck connecting to the 300 ohm terminals just above it, one wire per terminal.

 

[CZmok]

Thanks @LuvMyQuad !

I will change my antenna settings.

By the way... Should work FM radio also in SQ mode? My actuall setting is:

- 4 speakers in A speakers input (LF, RF, LB, RB --> 4 channels)
- Amp is switched to 4 channel mode on back side of amp
- FM input is pressed
- if selector is on 2ch --> play just front speakers
- if selector is set to any of 4 channel option (2+4, SQ, R-MTX or DISCRETE) then play nothing, just hum.


I'm not sure if its ok or bug of amp?

Thanks.

 

[par4ken]

thanks for You patience with me. So I have to use BLUE inputs instead of RED (see picture)?

View attachment 56987

Yes if you connect to the blue inputs (via Y connectors) you will have full control of the outputs (2X2) stereo only.

 

[CZmok]

Yes if you connect to the blue inputs (via Y connectors) you will have full control of the outputs (2X2) stereo only.

Thank You @par4ken !

How to do that if I have device just with 3,5 mm jack? Does exist some kind of reductions from 3,5 jack to 4 cinch (2x Y)?

Is thaht true, that this blue inpust is only one which is able to play in SQ? I thought it will be able to use more than one input for SQ. :-(

I have to read what exactly mean "monitor selectors" (4ch, 2ch-1, 2ch-2). Or do You know it? Maybe is possible somehow combine inputs and monitors...

 

[par4ken]

If you want to use SQ you have to use the stereo inputs (Aux) as you originally posted. Then switch the SQ button on, for decoding stereo there should be other options such as RM that might work better. SQ is meant primarily for SQ encoded records. The Amp needs to be set to 4-channel and speakers connected to the front and back outputs.

 

[CZmok]

If you want to use SQ you have to use the stereo inputs (Aux) as you originally posted. Then switch the SQ button on, for decoding stereo there should be other options such as RM that might work better. SQ is meant primarily for SQ encoded records. The Amp needs to be set to 4-channel and speakers connected to the front and back outputs.

hmm, that exactly does not work. Nothing plays, just hum. Records have to be SQ encoded? If I played for example from YouTube, then it will not work? Maybe that is the issue?

 

[Circular Vibes]

Anything 2 channel should give you 4 channel when you select SQ. There is no special signal to activate SQ. Has this receiver been serviced recently or the controls and switches cleaned?

 

[CZmok]

Anything 2 channel should give you 4 channel when you select SQ. There is no special signal to activate SQ. Has this receiver been serviced recently or the controls and switches cleaned?

Just for sure... If I will have settings like this:

- Switched to 4 channel mode on back side of amp
- 2 cinch (1 Y) are connected to AUX and other side of cable is 3,5 mm jack playing Youtube
- AUX input is selected on front side of amp
- 4 speakers are connected to A output (LF, RF, LB, RB) and selected this ring of speakers
- SQ is selected on front side of amp

it should play 4 channel sound and I should be able to control each speaker separately? If Yes, then It is gonna be bug probably.

Amp was serviced but the man did not know how to works SQ sound and other programs of amp and tell me to test it. ..

 

[LuvMyQuad]

Just for sure... If I will have settings like this:

- Switched to 4 channel mode on back side of amp
- 2 cinch (1 Y) are connected to AUX and other side of cable is 3,5 mm jack playing Youtube
- AUX input is selected on front side of amp
- 4 speakers are connected to A output (LF, RF, LB, RB) and selected this ring of speakers
- SQ is selected on front side of amp

it should play 4 channel sound and I should be able to control each speaker separately? If Yes, then It is gonna be bug probably.

Amp was serviced but the man did not know how to works SQ sound and other programs of amp and tell me to test it. ..

Leave it all connected as described above. But switch the front mode selector to discrete instead. You should hear stereo coming from the front channels.

 

[Circular Vibes]

You seem to have it hooked up right and understand how it should work. I think it needs service. I wonder if the 2/4 channel switch on the back has failed, is very dirty, or bypassed by a previous owner to get a louder 2 channel system when quad failed commercially. If you can get help from the person you bought it from or another tech, that seems the logical step.

 

[par4ken]

Just for sure... If I will have settings like this:

- Switched to 4 channel mode on back side of amp
- 2 cinch (1 Y) are connected to AUX and other side of cable is 3,5 mm jack playing Youtube
- AUX input is selected on front side of amp
- 4 speakers are connected to A output (LF, RF, LB, RB) and selected this ring of speakers
- SQ is selected on front side of amp

it should play 4 channel sound and I should be able to control each speaker separately? If Yes, then It is gonna be bug probably.

Amp was serviced but the man did not know how to works SQ sound and other programs of amp and tell me to test it. ..

You don't need any Y connectors to use SQ, what you were asking about before was to get stereo from both the front and the back, then you would need the Y connectors.
Everything else looks fine. Might be a problem with the amp.

 

[CZmok]

Leave it all connected as described above. But switch the front mode selector to discrete instead. You should hear stereo coming from the front channels.

I hear stereo from front speakers if 2-ch is selected on front side of amp. If I choose DISCRETE as You told me, then nothing gets out from speakers. You can check this video: New video by Štěpán Čmok (sorry for brightness).

 

[par4ken]

I hear stereo from front speakers if 2-ch is selected on front side of amp. If I choose DISCRETE as You told me, then nothing gets out from speakers. You can check this video: New video by Štěpán Čmok (sorry for brightness).

When you switch to discrete you have to connect to the discreet inputs. You seem to have skipped over SQ, you should try 2-4, SQ, R-MTX to see which sound the best for your program source. All 3 of those switch positions will transform your 2 channel input to 4 output channels.