Hi all
Just picked this little unit up think it’s an A/B setup. It’s a Matrix M400 but trying to find a schematic is a nightmare no luck at all. So hoping someone on here has one and refurbed or the actual schematic. It looks to be handmade not come across a mains in with a 0R resistor connected there before PET cap yeah so not sure what’s idea on that? Also there are no fuses at all again never seen that before either. I think it has some type of inbuilt relay protection unit fitted hence loosing the fuses.
Also the amount of electrolytics in there never seen so many. Is that a good or bad thing always thought less the better.
Also no trimmers so I’m assuming it’s fixed bias? If so need to work out which resistors are for the bias and probably need readings taken as it looks like it’s not been used in a while. So no doubt drifted.
The transformer not worked out spec on that yet but looking at the mosfets it’s probably good for 250 watt per channel pushed to the limit. Definitely a dual supply transformer poss 500va not sure of rails yet letting it run up on the Variac.
The fan is constantly running so think thermosistor or circuitry needs looking at. Not even hot. Unless it’s supposed to run continuously?
All in all the gear in there is pretty top spec. So if anyone has any info be much appreciated for sure. Even if it’s just bias ratings and voltages on the rails be great. I think I’ll re cap just something I’ve always done on older gear. Plus the caps in there pretty crap considering the rest of the components. Cost cutting suspect.
Pics attached.
Just picked this little unit up think it’s an A/B setup. It’s a Matrix M400 but trying to find a schematic is a nightmare no luck at all. So hoping someone on here has one and refurbed or the actual schematic. It looks to be handmade not come across a mains in with a 0R resistor connected there before PET cap yeah so not sure what’s idea on that? Also there are no fuses at all again never seen that before either. I think it has some type of inbuilt relay protection unit fitted hence loosing the fuses.
Also the amount of electrolytics in there never seen so many. Is that a good or bad thing always thought less the better.
Also no trimmers so I’m assuming it’s fixed bias? If so need to work out which resistors are for the bias and probably need readings taken as it looks like it’s not been used in a while. So no doubt drifted.
The transformer not worked out spec on that yet but looking at the mosfets it’s probably good for 250 watt per channel pushed to the limit. Definitely a dual supply transformer poss 500va not sure of rails yet letting it run up on the Variac.
The fan is constantly running so think thermosistor or circuitry needs looking at. Not even hot. Unless it’s supposed to run continuously?
All in all the gear in there is pretty top spec. So if anyone has any info be much appreciated for sure. Even if it’s just bias ratings and voltages on the rails be great. I think I’ll re cap just something I’ve always done on older gear. Plus the caps in there pretty crap considering the rest of the components. Cost cutting suspect.
Pics attached.
Attachments
I'm assuming no one knows much about these. Anyhow schematic would be great.
Problems going into protection mode sorted relay knackered. Also LEDs not very bright on hfe test. Think it's the LED chips which is also causing the fan to stay on it's 12v but got constant 6.3v running through so it's open. The ptc thermistor knackered but new one put in but spec no clue. Original on heating up would flicker from 53r to 180r would not sit at a specific reading despite constant heat source applied. New one in but think its curie point is 100r. So is that right for this model? No clue. But it's not switching off fan sitting at 22r. Not gonna get above that as fan running. So the LED chips I think are knackered or LEDs are on there way out. Which forms part of the fan circuitry. So if I change them out LEDs first cheap option if not I can get two new chips.
Sound well those exicon mosfets pretty darn good. Very surprised.
Also these new double sided pcbs what a nightmare getting the solder off seems to me its like a throw away job as you cannot get to the solder topside where components placed. Stupid design if you ask me.
Problems going into protection mode sorted relay knackered. Also LEDs not very bright on hfe test. Think it's the LED chips which is also causing the fan to stay on it's 12v but got constant 6.3v running through so it's open. The ptc thermistor knackered but new one put in but spec no clue. Original on heating up would flicker from 53r to 180r would not sit at a specific reading despite constant heat source applied. New one in but think its curie point is 100r. So is that right for this model? No clue. But it's not switching off fan sitting at 22r. Not gonna get above that as fan running. So the LED chips I think are knackered or LEDs are on there way out. Which forms part of the fan circuitry. So if I change them out LEDs first cheap option if not I can get two new chips.
Sound well those exicon mosfets pretty darn good. Very surprised.
Also these new double sided pcbs what a nightmare getting the solder off seems to me its like a throw away job as you cannot get to the solder topside where components placed. Stupid design if you ask me.
According to an owner in 2011 it outputs ( approx ) "200W/Channel " at 4ohms and there seems to be various builds of it lending to the belief that "its a kit" or a small company as it does not conform to modern British electrical standards .
"Company " ? owned by "Andy " who wound his own transformers --one sold on eBay for £25 .
Got more info -Mosfet powered PA amplifier for DJ Band Bar Club 19-bands-bars-theatres and yes its ( or was ) a UK manufactured item also for churches-schools --seems Rick Wakeman had one as well as the "Band of the Royal Marines " .
Soft start-SC protection -switchable output clip protection -short circuit /overheat protection --Thermistor controlled twin speed fans .
At 8 ohms it outputs 120Watts.
There you go Shock -BTW -- how is your cat ?
"Company " ? owned by "Andy " who wound his own transformers --one sold on eBay for £25 .
Got more info -Mosfet powered PA amplifier for DJ Band Bar Club 19-bands-bars-theatres and yes its ( or was ) a UK manufactured item also for churches-schools --seems Rick Wakeman had one as well as the "Band of the Royal Marines " .
Soft start-SC protection -switchable output clip protection -short circuit /overheat protection --Thermistor controlled twin speed fans .
At 8 ohms it outputs 120Watts.
There you go Shock -BTW -- how is your cat ?
Cheers Ducan. Yeah it’s strange set up and definitely does not follow your normal circuitry. Lot of caps in there. Funny enough I replaced all the psu caps one I pulled on it and hey ho the cap came off but the internal positive and negative terminals stayed on the board that’s a first for sure. I think it’s supposed to have buzz 900 and 905 mossies but these in it are pretty darn good. I mean without tone controls I’m hearing stuff not picked up before. Running through a pairs of 70s PA speakers the whole house has been shaking ha ha.
Thanks for info and explains why not much information about and obviously not willing to part with schematics for it I’ve heard some bit funny about that. Mind you don’t help when you need to fix it.
Can’t knock it bloody good little amp.
Sort LEDs out next week. Not sure on the output on windings again not your typical voltages. £25 quid that’s sounds a bargain to me.
Did think it was a type of kit. Mind you I only ended up paying 25 quid for whole unit cost me 8 quid to get it going. So think I’m quids in there.
Gives me something to go by.
Oh Matilda me cat still not 100% but got the cat’s protection involved she’s registered with them because of me cancer and heart so want her to go to a good home. But there gonna cover the cost of scans biopsy etc. But hopefully nothing too serious. Bless her. What’s really bad is her original medical record has been completely re written from original don’t think that’s legal I’m assuming that’s because they where telling me nothing wrong but on her records was saying there is. But they’ve tried to re write that but there stuffed there for sure. So I think they want her well before I kick the bucket as they say. Thanks for asking.
Thanks for info and explains why not much information about and obviously not willing to part with schematics for it I’ve heard some bit funny about that. Mind you don’t help when you need to fix it.
Can’t knock it bloody good little amp.
Sort LEDs out next week. Not sure on the output on windings again not your typical voltages. £25 quid that’s sounds a bargain to me.
Did think it was a type of kit. Mind you I only ended up paying 25 quid for whole unit cost me 8 quid to get it going. So think I’m quids in there.
Gives me something to go by.
Oh Matilda me cat still not 100% but got the cat’s protection involved she’s registered with them because of me cancer and heart so want her to go to a good home. But there gonna cover the cost of scans biopsy etc. But hopefully nothing too serious. Bless her. What’s really bad is her original medical record has been completely re written from original don’t think that’s legal I’m assuming that’s because they where telling me nothing wrong but on her records was saying there is. But they’ve tried to re write that but there stuffed there for sure. So I think they want her well before I kick the bucket as they say. Thanks for asking.
Yeah I read up about them being hi end components. Do sound good for sure had it running since around 10am. No hiccups at all they have also installed small ceramic caps across the pins on base apparently something to do with ringing not come across that before.
She’s not a lap cat but loves to lye over me legs and feet on the couch but if I get up she wraps her legs and claws in to stop me getting up ha ha and another one is head like we do against pillow asleep. But must admit first cat I’ve had that’s had so many issues.
Oh and she’s like a dog she has her soil spots in garden and does the rolling around in it and I have to rub her belly at same time. Tell ya she has some strange habits. Another is sitting in sink with tap running she’s quite happy sitting there getting soaking wet ha. Cats usually hate water not her. But what makes me laugh is when I’ve stroked her or rubbed my head on her she gives me the look and then starts having a wash so I keep doing it can go on for about an hour ha ha. Anyhow that’s half of it. Can’t beat em they like to rule the roost.
So you never got another then?
She’s not a lap cat but loves to lye over me legs and feet on the couch but if I get up she wraps her legs and claws in to stop me getting up ha ha and another one is head like we do against pillow asleep. But must admit first cat I’ve had that’s had so many issues.
Oh and she’s like a dog she has her soil spots in garden and does the rolling around in it and I have to rub her belly at same time. Tell ya she has some strange habits. Another is sitting in sink with tap running she’s quite happy sitting there getting soaking wet ha. Cats usually hate water not her. But what makes me laugh is when I’ve stroked her or rubbed my head on her she gives me the look and then starts having a wash so I keep doing it can go on for about an hour ha ha. Anyhow that’s half of it. Can’t beat em they like to rule the roost.
So you never got another then?
It was part of the family and we really missed it when it died and your right it always thought it owned the house not me, just couldn't go through the loss again.
Mosfets are inclined to VHF oscillation given the chance by bad circuit design or layout as you are a member of the Radio Museum you might have come across them in HF "old school " communications receivers or old CRT TV tuners , you know the ones with the multiswitches for the channel tuner with PC86/88-PC97/900--PCC189 valves.
Mosfets are inclined to VHF oscillation given the chance by bad circuit design or layout as you are a member of the Radio Museum you might have come across them in HF "old school " communications receivers or old CRT TV tuners , you know the ones with the multiswitches for the channel tuner with PC86/88-PC97/900--PCC189 valves.
I understand that quite surprising how it hits ya. Definitely like losing family member. I was the same to be honest but when I was still married she went on and on about getting a kitten so I gave in. But funny really as she was her cat but was quite happy to leave her behind but to be honest I'm glad she did. Great companion and keeps me going so plus allround for me.
Yep I'm with you now. Like say mosfets new to me so it's all learning curve. But must remember there mimicking valves.
All switched off now ordered some new LEDs see if that does the trick. If not ill get some nos chips. There's a tip in the circuit for fan motor I think its 121 something like that as well but it's riveted in yuk easier with nut and bolt. Haven't tested that funny enough check that tomorrow. All on front end with the gain controls completely separate from main board.
Yep I'm with you now. Like say mosfets new to me so it's all learning curve. But must remember there mimicking valves.
All switched off now ordered some new LEDs see if that does the trick. If not ill get some nos chips. There's a tip in the circuit for fan motor I think its 121 something like that as well but it's riveted in yuk easier with nut and bolt. Haven't tested that funny enough check that tomorrow. All on front end with the gain controls completely separate from main board.
Well no schematic but job done. The ic for vu is for green and red LEDs someone put in orange not sure make a difference but it now works on changing them out. You need it at - 12bd before they kick in and that's loud enough for sure got to 0 centre db house could not take nor me ha. Fan sorted the triac knackered so switched on all the time new one installed. Odd one the dials have green LEDs in them but someone had decided to to cut off the leads. So there now working. So took bit of time but job done but it does make me wonder why people mess around with gear and bugger it up. Don't get just leave it alone.
Sound pretty exceptional obviously running it through PA speakers too much power for my other speakers. Just go bang.
Done.
Sound pretty exceptional obviously running it through PA speakers too much power for my other speakers. Just go bang.
Done.
Well it's had a week now of non stop use 8 to 10 hours per day and caps truly bedded in now.
Sound exceptional good all round acoustics in the low mids and highs. Good detail not sterile at all. Handles all types of music pop, R and B reggae classical rock soul jazz etc and through TV it catches you out. Volume up to clipping point not for long may I add no distortion still nice and transparent no loss of detail. So I think price wise although not many around or any information on them worth a punt.
Sound exceptional good all round acoustics in the low mids and highs. Good detail not sterile at all. Handles all types of music pop, R and B reggae classical rock soul jazz etc and through TV it catches you out. Volume up to clipping point not for long may I add no distortion still nice and transparent no loss of detail. So I think price wise although not many around or any information on them worth a punt.