Distortion!! Technics SU-Z35 AMP /Technics SB-3110A Speakers - UK Vintage Radio Repair and Restoration Discussion Forum

treble6 · 10th Apr 2018, 7:21 pm

Hello, I have the technics amp and speaker combo thats used to be my dads.

Basically I was looking to set up the amp with my sony bm10 bluetooth receiver and got it too work but the speakers are very distorted....

now i did pull the speakers apart as i was going to build some new enclosures as the originals have seen better days.. the lacquer has peeled in places.
im wondering if i have either wired the speakers back in wrongly or if the amp has blown or something?

any advice greatly appreciated.

the speakers are 2 way.. but use just a +/- connection, theres no HF/LF

paulsherwin · 10th Apr 2018, 7:31 pm

Why have you wrecked the original speakers? It's a difficult and skilled job to build good speaker enclosures, even if you know what you're doing.

Hifi speakers contain a crossover circuit to send the appropriate signal to each driver. It's also important that the speakers are all phased correctly (i.e. they all move in and out together).

From what you've said so far, it would probably be better to chuck what's left of the Technics speakers in the bin and buy a new pair of vintage speakers from a local eBay seller. They often don't cost much.

treble6 · 10th Apr 2018, 7:52 pm

Haha I havent wrecked them, they are just a bit worse for wear and i took a look at them to see if it would be simple to just remove the peeling lacquer or construct an exact copy of the enclosure themselves, what i would like to know really is the wiring situation or configuration as i thought i wired them back in as they came out, there 4 wires off the crossover, a green and red, it appeared the on both the left loudspeaker and the right loudspeaker the green went to the (-) and red (+)
but on the tweeters one tweeter the black went to (-) and yellow (+) and on the other speaker the tweeter was wired the opposite? could this be correct?

paulsherwin · 10th Apr 2018, 8:21 pm

Well, two of the wires will be for the woofer and the other two for the tweeter. Both speaker units should be wired in the same way. The speakers will sound better with the tweeter wired one way round or the other.

There should be no obvious distortion if the speakers are wired like this, so any distortion will be caused by something else, such as overloading the amplifier input. Is the distortion still there if you listen on headphones plugged into the amp headphone socket?

treble6 · 10th Apr 2018, 8:31 pm

I've wired both right and left exactly the same now and the distortion has gone. I think I have an amp issue though as the balance adjuster will select the left speaker and completely cut the right speaker out which it should but if I switch the the right speaker fully I can still hear music coming from the left. It's low volume but I can still hear it.

I've just taken the top case off the amp and there's dust dating back to the 80's in there, but no easy way to get at that balance switch from behind.

kevinaston1 · 10th Apr 2018, 11:26 pm

Hi Treble6,

You will find a service manual on the Electrotanya website, which will show you (in a basic way) how to dismantle the front panel to get to the balance control.

Hopefully, it will clean up with switch cleaner. If not, a replacement balance control will be difficult to source.

Kevin

Diabolical Artificer · 11th Apr 2018, 6:35 am

These are IC amp powered amplifiers I think but still not to be mucked about with if you don't know what your doing. still that never stopped most of us when we were beginning.

When mucking about with anything electronic, it's a good idea to take loads of good resolution pics of the guts especially wiring details.

As your very unlikely to have the balance cranked all the way over to one side, best leave be or follow Kevin's advice.

Hope you enjoying your Dad's hifi, Andy.

ben · 11th Apr 2018, 10:33 am

If speakers sound rough or 'rattly', then you may have perished foam suspensions - inspect yours. This is a very common problem. example here

If the foam is rotted you would be well advised to just buy some new speakers. Places like cash converters usually have them for cheap.

A shot of contact spray (Servisol 10 is probably easiest to find) in the balance control will probably solve your troubles there.

treble6 · 11th Apr 2018, 11:53 am

Many thanks to all for input so far! and its been great to hear the system once again! I remember when my dad had this system, he had a deck as well but that got thrown at some point!
To be honest still sounds pretty good! but seems strange to hook up my laptop to it though. haha.
I have had trouble with the Sony BM10 blue tooth receiver. It seem to start to work if plugged into aux inputs but then stops working after a while, and the laptop says no speakers attached to receiver, so maybe some contact spray in the inputs as well?
The volume slider also misses sometimes, when you slide up or down, and the sound sort of crackles.

But being the adventurous fellow I am I managed to get access to the bass, treble and balance board, which was actually just a few screws under the unit and a few tabs holding the board in place. It's still attached to the other boards so I'm going extra careful!!
So I'll grab some contact spray and give it a whirl!

As for the mountain of vintage dust, would a can of 'air' be the best bet? I don't want to get the vacuum in there really. I was thinking a small paint brush too.

PsychMan · 11th Apr 2018, 3:42 pm

If the laptop is losing sight of the Bluetooth module when it stops working, Id imagine the module is faulty and no amount of contact cleaner will make a difference. Might want to check its power supply is OK, if it is might as well chuck it as its likely tiny SMD stuff inside and beyond economic repair.

A noisy volume slider would benefit from some switch cleaner. As with the pots though, you need to make sure you get the cleaner inside to the slider or pot and use it sparingly. Often pots have little cut outs you can stick the nozzle of an aerosol switch cleaner. Once you get the cleaner inside, work the control back and forth a good number of times and then test.

Using a vacuum is fine, or air duster. Just don't go assaulting any cables ribbons or other stuff inside with the vaccum nozzle !

. In the grand scheme of things a little dust is not going to have any negative impacts so just be careful and if you can't get it perfectly clean just leave it.

One more thing, try and use something like servisol super 10 which lubricates as well as cleans. Some switch cleaners are solvents that evaporate and leave controls dry and rough to use. WD40 would lubricate and perform switch cleaning to an extent, long term its pretty crap though and will cause more problems in my experience. Has hundreds of uses, and is crap at most of them

treble6 · 12th Apr 2018, 8:05 pm

Hi, the laptop is still connected to the Bluetooth receiver but it seems as though the receiver is losing the signal from the amp inputs?

But it's all fine if I just plug my laptop directly to the amp though the aux inputs.

On a side note. I have to say I'm actually surprised how well the system sounds. It's not been fired up for a good amount of years! It's pretty hefty at mid volume!!

And I just did a very light dusting job with a small paint brush and careful hovering, it's not perfect but much better!

So it 'sounds' like Servisol 10 is the best bet for the volume and various switch sliders then?

Thank you very much for the info fella's.

Diabolical Artificer · 13th Apr 2018, 6:58 am

Glad you're enjoying it. The SU series were not one of Technic's better amps, but still miles better than most contemporary amplifiers modern music centres.

"So it 'sounds' like Servisol 10 is the best bet for the volume and various switch sliders then?" Everyone swears by there favourite cleaner, bit like asking what the best football team is.

A.

treble6 · 14th Apr 2018, 12:29 pm

Yes, totally agree its not top notch but for the age of the amp which isn't much different than myself just for it to work let alone produce a half decent sound have to say I'm pretty chuffed!

So i take it you would maybe advise a different cleaner then?
any suggestions welcome... I can then make a choice.

PsychMan · 14th Apr 2018, 8:13 pm

I only mentioned servisol super 10 as a cleaner because it lubricates and cleans and is easy to get. Its not necessarily the best but it does what you need. Deoxit D5 is good but costs a lot to import, Im sure there will be many other brands that are equal or better. Ultimately it doesn't really matter which one, just try and avoid WD40 (in my opinion)

10th Apr 2018, 7:21 pm	#1
treble6 Retired Dormant Member Join Date: Apr 2018 Location: Bristol, UK. Posts: 6	Distortion!! Technics SU-Z35 AMP /Technics SB-3110A Speakers Hello, I have the technics amp and speaker combo thats used to be my dads. Basically I was looking to set up the amp with my sony bm10 bluetooth receiver and got it too work but the speakers are very distorted.... now i did pull the speakers apart as i was going to build some new enclosures as the originals have seen better days.. the lacquer has peeled in places. im wondering if i have either wired the speakers back in wrongly or if the amp has blown or something? any advice greatly appreciated. the speakers are 2 way.. but use just a +/- connection, theres no HF/LF

10th Apr 2018, 7:31 pm	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,968	Re: Distortion!! Technics SU-Z35 AMP /Technics SB-3110A Speakers Why have you wrecked the original speakers? It's a difficult and skilled job to build good speaker enclosures, even if you know what you're doing. Hifi speakers contain a crossover circuit to send the appropriate signal to each driver. It's also important that the speakers are all phased correctly (i.e. they all move in and out together). From what you've said so far, it would probably be better to chuck what's left of the Technics speakers in the bin and buy a new pair of vintage speakers from a local eBay seller. They often don't cost much.

10th Apr 2018, 7:52 pm	#3
treble6 Retired Dormant Member Join Date: Apr 2018 Location: Bristol, UK. Posts: 6	Re: Distortion!! Technics SU-Z35 AMP /Technics SB-3110A Speakers Haha I havent wrecked them, they are just a bit worse for wear and i took a look at them to see if it would be simple to just remove the peeling lacquer or construct an exact copy of the enclosure themselves, what i would like to know really is the wiring situation or configuration as i thought i wired them back in as they came out, there 4 wires off the crossover, a green and red, it appeared the on both the left loudspeaker and the right loudspeaker the green went to the (-) and red (+) but on the tweeters one tweeter the black went to (-) and yellow (+) and on the other speaker the tweeter was wired the opposite? could this be correct?

10th Apr 2018, 8:21 pm	#4
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,968	Re: Distortion!! Technics SU-Z35 AMP /Technics SB-3110A Speakers Well, two of the wires will be for the woofer and the other two for the tweeter. Both speaker units should be wired in the same way. The speakers will sound better with the tweeter wired one way round or the other. There should be no obvious distortion if the speakers are wired like this, so any distortion will be caused by something else, such as overloading the amplifier input. Is the distortion still there if you listen on headphones plugged into the amp headphone socket?

10th Apr 2018, 8:31 pm	#5
treble6 Retired Dormant Member Join Date: Apr 2018 Location: Bristol, UK. Posts: 6	Re: Distortion!! Technics SU-Z35 AMP /Technics SB-3110A Speakers I've wired both right and left exactly the same now and the distortion has gone. I think I have an amp issue though as the balance adjuster will select the left speaker and completely cut the right speaker out which it should but if I switch the the right speaker fully I can still hear music coming from the left. It's low volume but I can still hear it. I've just taken the top case off the amp and there's dust dating back to the 80's in there, but no easy way to get at that balance switch from behind.

10th Apr 2018, 11:26 pm	#6
kevinaston1 Hexode Join Date: Aug 2014 Location: Featherstone, West Yorkshire, UK. Posts: 386	Re: Distortion!! Technics SU-Z35 AMP /Technics SB-3110A Speakers Hi Treble6, You will find a service manual on the Electrotanya website, which will show you (in a basic way) how to dismantle the front panel to get to the balance control. Hopefully, it will clean up with switch cleaner. If not, a replacement balance control will be difficult to source. Kevin

11th Apr 2018, 6:35 am	#7
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,669	Re: Distortion!! Technics SU-Z35 AMP /Technics SB-3110A Speakers These are IC amp powered amplifiers I think but still not to be mucked about with if you don't know what your doing. still that never stopped most of us when we were beginning. When mucking about with anything electronic, it's a good idea to take loads of good resolution pics of the guts especially wiring details. As your very unlikely to have the balance cranked all the way over to one side, best leave be or follow Kevin's advice. Hope you enjoying your Dad's hifi, Andy. __________________ Curiosity hasn't killed this cat...so far.

11th Apr 2018, 10:33 am	#8
ben Dekatron Join Date: Aug 2006 Location: Madrid, Spain / Wirral, UK Posts: 7,498	Re: Distortion!! Technics SU-Z35 AMP /Technics SB-3110A Speakers If speakers sound rough or 'rattly', then you may have perished foam suspensions - inspect yours. This is a very common problem. example here If the foam is rotted you would be well advised to just buy some new speakers. Places like cash converters usually have them for cheap. A shot of contact spray (Servisol 10 is probably easiest to find) in the balance control will probably solve your troubles there. __________________ Regards, Ben.

11th Apr 2018, 11:53 am	#9
treble6 Retired Dormant Member Join Date: Apr 2018 Location: Bristol, UK. Posts: 6	Re: Distortion!! Technics SU-Z35 AMP /Technics SB-3110A Speakers Many thanks to all for input so far! and its been great to hear the system once again! I remember when my dad had this system, he had a deck as well but that got thrown at some point! To be honest still sounds pretty good! but seems strange to hook up my laptop to it though. haha. I have had trouble with the Sony BM10 blue tooth receiver. It seem to start to work if plugged into aux inputs but then stops working after a while, and the laptop says no speakers attached to receiver, so maybe some contact spray in the inputs as well? The volume slider also misses sometimes, when you slide up or down, and the sound sort of crackles. But being the adventurous fellow I am I managed to get access to the bass, treble and balance board, which was actually just a few screws under the unit and a few tabs holding the board in place. It's still attached to the other boards so I'm going extra careful!! So I'll grab some contact spray and give it a whirl! As for the mountain of vintage dust, would a can of 'air' be the best bet? I don't want to get the vacuum in there really. I was thinking a small paint brush too.

11th Apr 2018, 3:42 pm	#10
PsychMan Octode Join Date: Jun 2013 Location: Fleet, Hampshire, UK Posts: 1,765	Re: Distortion!! Technics SU-Z35 AMP /Technics SB-3110A Speakers If the laptop is losing sight of the Bluetooth module when it stops working, Id imagine the module is faulty and no amount of contact cleaner will make a difference. Might want to check its power supply is OK, if it is might as well chuck it as its likely tiny SMD stuff inside and beyond economic repair. A noisy volume slider would benefit from some switch cleaner. As with the pots though, you need to make sure you get the cleaner inside to the slider or pot and use it sparingly. Often pots have little cut outs you can stick the nozzle of an aerosol switch cleaner. Once you get the cleaner inside, work the control back and forth a good number of times and then test. Using a vacuum is fine, or air duster. Just don't go assaulting any cables ribbons or other stuff inside with the vaccum nozzle ! . In the grand scheme of things a little dust is not going to have any negative impacts so just be careful and if you can't get it perfectly clean just leave it. One more thing, try and use something like servisol super 10 which lubricates as well as cleans. Some switch cleaners are solvents that evaporate and leave controls dry and rough to use. WD40 would lubricate and perform switch cleaning to an extent, long term its pretty crap though and will cause more problems in my experience. Has hundreds of uses, and is crap at most of them

12th Apr 2018, 8:05 pm	#11
treble6 Retired Dormant Member Join Date: Apr 2018 Location: Bristol, UK. Posts: 6	Re: Distortion!! Technics SU-Z35 AMP /Technics SB-3110A Speakers Hi, the laptop is still connected to the Bluetooth receiver but it seems as though the receiver is losing the signal from the amp inputs? But it's all fine if I just plug my laptop directly to the amp though the aux inputs. On a side note. I have to say I'm actually surprised how well the system sounds. It's not been fired up for a good amount of years! It's pretty hefty at mid volume!! And I just did a very light dusting job with a small paint brush and careful hovering, it's not perfect but much better! So it 'sounds' like Servisol 10 is the best bet for the volume and various switch sliders then? Thank you very much for the info fella's.

13th Apr 2018, 6:58 am	#12
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,669	Re: Distortion!! Technics SU-Z35 AMP /Technics SB-3110A Speakers Glad you're enjoying it. The SU series were not one of Technic's better amps, but still miles better than most contemporary amplifiers modern music centres. "So it 'sounds' like Servisol 10 is the best bet for the volume and various switch sliders then?" Everyone swears by there favourite cleaner, bit like asking what the best football team is. A. __________________ Curiosity hasn't killed this cat...so far.

14th Apr 2018, 12:29 pm	#13
treble6 Retired Dormant Member Join Date: Apr 2018 Location: Bristol, UK. Posts: 6	Re: Distortion!! Technics SU-Z35 AMP /Technics SB-3110A Speakers Yes, totally agree its not top notch but for the age of the amp which isn't much different than myself just for it to work let alone produce a half decent sound have to say I'm pretty chuffed! So i take it you would maybe advise a different cleaner then? any suggestions welcome... I can then make a choice.

14th Apr 2018, 8:13 pm	#14
PsychMan Octode Join Date: Jun 2013 Location: Fleet, Hampshire, UK Posts: 1,765	Re: Distortion!! Technics SU-Z35 AMP /Technics SB-3110A Speakers I only mentioned servisol super 10 as a cleaner because it lubricates and cleans and is easy to get. Its not necessarily the best but it does what you need. Deoxit D5 is good but costs a lot to import, Im sure there will be many other brands that are equal or better. Ultimately it doesn't really matter which one, just try and avoid WD40 (in my opinion)