Hi, I have one of this, I got it from my mother's uncle. The same problem with the balance switch and the imput selector... Thanks for you video!! I also have the original speakers, AM/FM tunner and stereo casset deck
I'm sure you will find someone to buy it :-D The old amplifiers are simple, no digital madness to fail in a complicated way. I have an ancient Pioneer Sa-706 amplifier, it has never failed me.
I like you to put 10 vids on a day cos I enjoy watching them all saw the archive one and VCR one and this one today tell the troll to pee off and mind his ow business, keep up the great work and put MORE on
I don't communicate with the troll. He sends much 1 way communication but he is banned and all the names he uses go directly to the bit recycler. Reminds me of an old boy that lived up the street when I was a kid old Eddie Mills. He would phone the cops on a 5-year-old kicking a tin can down the street. No exaggeration he called the cops on me and a buddy when we were about seven playing street hockey because the ball once rolled into his front yard and we were trying to dig the ball out from his hedge and he phoned the cops on us wanted 7-year-olds charged with trespass. That's the mentality of John shithead.
I love these little amps to work on. I know you think it's not worth sourcing parts, but I'm sure you'd find one of those switches on another piece of junk in short time. But yeah, I know, it's not an important enough project to worry about. I love the dual amp layout, makes fault finding a lot more easier. Oh, Love the newer cat 'intro' too, Classic!
I was working on a buddies Sanyo receiver of the same power and vintage that had a speaker switch problem. These were round buttons and there was a black plastic washer between the switch and front panel that had a split in it. That washer was hanging up and preventing the button from depressing fully, when i removed it the the switch worked fine. You have a different problem thats not fixable without a new switch (good luck with that). i cleaned all the controls and replaced some power supply caps that looked suspect and a power output module that had gone south. The amp is back in his home office and working just fine, for a 40 year old unit the fix was not bad - about $20 in parts.
Nice repair on that Akai. Like the clipping light to save your speakers. that was a bit rare back in those days to have that feature. Not many units had this yet. Btw, don’t worry to much about Johnny, tangle with the wrong person, and someone will lump him up... starting with a fat eye or two.
Always remember to dip your wick LOL :D Seriously though that's a great tip. Ebay is probably the best place to get flux these days, though Big Clive made his own by dissolving rosin in IPA
Make sure its a flux designed for use on electronic circuits; my boss bought several different liquid fluxes on line, only to find when they arrived that the bottle said "not for electronics use". Rosin flux is best; that's *flux* and not soldering paste, which contains powdered solder! Fluxes designed specifically for leadfree solder are both conductive and corrosive, and must be removed from the circuit board afterwards (typically water soluble). Rosin flux is generally non-conductive and noncorrosive, and cleans up with alcohol.
@@countzero1136 , beer, soda and coffee are all horrendously corrosive to circuit boards, and just a drop or two can do major damage, especially to double-sided or digitalized boards.
I have u04 its super sounding, phono input best i heard, works perfect, meters i think are slow, cliping i never saw, compared to marantz 7000, luxman l4, yamaha a 1020 it is winer
Great amplifier, legendary... What are some of the easiest amplifiers to work on? Anything stand out? Something very serviceable and therefore should last a bit longer. Some that come to mind are the early Sansuis or even those Yamaha AX700s
Well i'm not the man you're asking but i'll throw my hat in the ring... pioneer a30 I'd say. Super simple but also doesn't use STKs, you can repair that thing no sweat and do it for nothing. And it's not some anemic thing either, still has some juice and very clean. Unfortunately there's no service manual online which is kinda lame. And I'm talking about the original one from the 80s, if you web searched pioneer a30 you'll find they've since made a new amp with the same name... ugh.
If you compare the before and after sound, it's night and day. The "before" sound was harsh and awful. I initially thought it was room echo and the microphone doing injustice. But the "after" sound made a huge difference. And I'm also inclined to consider rail voltage imbalance as the cause. But it would have been great to have tried it with a sine wave and a scope before fixing it. About the switch, it can be a pain to source an appropriate one. And at $25-50 cost to your door, it probably would have cost twice as much as the market value of the unit. Good idea about swapping switches. I did the same on a Teac R2R swapping the speed switch for the 7/10" reel switch. After all I didn't use 7" reels much and with servo tension, the difference was minimal.
Oh yes it was night and day. Voltage imbalance to voltage amp the cause and likely the bad solder at the regulator. As to switches you are right in the cost and then there is the surprise when some dipshit at the supplier doesn't follow directions to mail parts and sends FedEx and they stick their 37.50 broker fee on top. Someone has sent me something for repair and they sent ur DHL. Fortunately DHL now requires payment of broker fees before they deliver. They are calling every day and i am not accepting. So eventually the person will get their unrepaired unit back with a bull for return shipping. FedEx just leaves it at the door and sends the bill 2 weeks later.
that clipping light is a nice feature even a lot of high end amps don't have that. i guess it monitors the speaker output for distortion? is is possible to add one to other amps that don't have it?
I think that the clipping light detects a DC component in the speaker output. Somw amplifiers had automatic safety features which disconnected the speakers
I had the opposite reaction to the flaw you found in the switch. Since you found the broken nub (seemingly in one piece), and since the amplifier isn't worth enough to chase down a replacement, and since you were going to swap the switch with an unbroken one that isn't used as much, my reaction would have been - let me see if I can repair the switch nub with some plastic glue. What would there be to lose, and even if it's a little more fragile, it won't be used all that often? After all, this repair was just for the fun of it anyway. Why not try the switch repair?
I have tried a similar thing on a Technics amplifier. The plastic glue did not support the pieces toghether enough and the switch was still kind of useless. It was a simpler switch and I was able to find a... kinda compatible replacement on aliexpress.
For the sake of testing, i have 5x panasonic small home theater speakers rated at 5ohm. Would i damage them or the amplifier if I were use them for testing when diagnosing an issue like this on any amp? Thanks for taking us on your journey to fix these things, really helps a novice like me.
They're not actually all that complex, and can be repaired (Even without 3D printing the plastic bits, though that does make it easier these days), though they're fiddly to work on, but hey, if you can't get a replacement, what ya gonna do?
I have a very similar AKAI that has the strangest problem: It sounds fine and works well, but when I turn it off it keeps playing for quite a few seconds (10 to 30 depending on the volume setting) and then clips and shuts off. Does anybody have a clue?
It seems your unit leaves the speakers connected on shut-down. Many amplifiers use a relay to disconnect their speakers during power on/off so this effect is not heard.
When the light comes on your driving the outputs into saturation put a scope on the outputs and you will see it 300 watt speakers would still do the same thing
Uhhh, isn't this your FIRST ever amplifier?? It's worth fixing for posterity and nostalgia alone! Smh, you're talking about it like its just an old POS. lol. (it might be) But I would have thought it had a higher value to YOU?
True. If you were to feed 25 watts of pure clean power through a 0.5 watt speaker, she cooked. But clipping still can damage a speaker, let's say a 15 watt speaker may be ok with 25 watts of clean power but 30 watts of clipping will make that speaker receive more of a DC voltage and the voice coil will have less air cooling and cook prematurely.
@@Thanson199415 What does it mean to feed power through a speaker? Answer = poorly stated assertion. If you cause a 0.5w speaker to dissipate 25watts then yes it will burn. Clipping may mean an increase in DC at the load only if the amplifier has no output capacitor or if it is not transformer coupled. A direct ie- no cap output amp driving a load is a BAD idea, but even so if the clipping occurs in a balanced way at both rails, then there will be no increase in a DC component.
Clipping certainly does blow speakers. More so than over power. I replaced drivers in a set of very expensive kef speakers more than once when the teenager if the house had a party when his parents were away and cooked the speakers with a 50 watt amp. The speakers rated 200 watts. The speakers however were the least of the kids worry. Even though they cost over $600 to repair that was nothing compared to the damage his friends did to the house. About 80,000 in damage.
@@12voltvids and so you were there with your triggered oscilloscope monitoring the situation as the kid did this, and you saw clipping? The 20w speakers driven by a 50w capable amp, gee what could go wrong? You have a story, but I doubt it is correct.
That clipping feature should have been a standard on all home amplifiers.
Hi, I have one of this, I got it from my mother's uncle. The same problem with the balance switch and the imput selector... Thanks for you video!! I also have the original speakers, AM/FM tunner and stereo casset deck
I'm sure you will find someone to buy it :-D
The old amplifiers are simple, no digital madness to fail in a complicated way.
I have an ancient Pioneer Sa-706 amplifier, it has never failed me.
I really like Japanese integrated amplifiers from that era, not expensive and easy on the ears.
I have an Akai sounds great after switches cleaned.
This is so cool, I like it quite a bit when you talk about your life and the devices that you used. Cheers from Italy. :-)
I love the machines of this era
I like you to put 10 vids on a day cos I enjoy watching them all saw the archive one and VCR one and this one today tell the troll to pee off and mind his ow business, keep up the great work and put MORE on
I don't communicate with the troll. He sends much 1 way communication but he is banned and all the names he uses go directly to the bit recycler. Reminds me of an old boy that lived up the street when I was a kid old Eddie Mills. He would phone the cops on a 5-year-old kicking a tin can down the street. No exaggeration he called the cops on me and a buddy when we were about seven playing street hockey because the ball once rolled into his front yard and we were trying to dig the ball out from his hedge and he phoned the cops on us wanted 7-year-olds charged with trespass. That's the mentality of John shithead.
@@12voltvids well done Dave love your videos you are the top guy you really know your stuff
I love these little amps to work on. I know you think it's not worth sourcing parts, but I'm sure you'd find one of those switches on another piece of junk in short time. But yeah, I know, it's not an important enough project to worry about. I love the dual amp layout, makes fault finding a lot more easier. Oh, Love the newer cat 'intro' too, Classic!
I was working on a buddies Sanyo receiver of the same power and vintage that had a speaker switch problem. These were round buttons and there was a black plastic washer between the switch and front panel that had a split in it. That washer was hanging up and preventing the button from depressing fully, when i removed it the the switch worked fine. You have a different problem thats not fixable without a new switch (good luck with that).
i cleaned all the controls and replaced some power supply caps that looked suspect and a power output module that had gone south. The amp is back in his home office and working just fine, for a 40 year old unit the fix was not bad - about $20 in parts.
Nice repair on that Akai. Like the clipping light to save your speakers. that was a bit rare back in those days to have that feature.
Not many units had this yet.
Btw, don’t worry to much about Johnny, tangle with the wrong person, and someone will lump him up... starting with a fat eye or two.
Thanks, Dave for that tip on dipping solder wick in flux ! Will try to find flux in my area! Sure miss Radio Shack!
Always remember to dip your wick LOL :D
Seriously though that's a great tip. Ebay is probably the best place to get flux these days, though Big Clive made his own by dissolving rosin in IPA
Make sure its a flux designed for use on electronic circuits; my boss bought several different liquid fluxes on line, only to find when they arrived that the bottle said "not for electronics use". Rosin flux is best; that's *flux* and not soldering paste, which contains powdered solder! Fluxes designed specifically for leadfree solder are both conductive and corrosive, and must be removed from the circuit board afterwards (typically water soluble). Rosin flux is generally non-conductive and noncorrosive, and cleans up with alcohol.
@@countzero1136 some folks don't know that IPA is isopropyl alcohol, and not beer...
@@goodun2974 Good point - especially given that Big Clive was mentioned LOL :)
@@countzero1136 , beer, soda and coffee are all horrendously corrosive to circuit boards, and just a drop or two can do major damage, especially to double-sided or digitalized boards.
great class and explanation! . Is it advisable to put thermal paste between the Darlings and the heatsink? what kind do you recommend?
I have u04 its super sounding, phono input best i heard, works perfect, meters i think are slow, cliping i never saw, compared to marantz 7000, luxman l4, yamaha a 1020 it is winer
I have this same device, with a little problem. Would be great to quiz your mind on a solution!
Nice one
Great amplifier, legendary... What are some of the easiest amplifiers to work on? Anything stand out? Something very serviceable and therefore should last a bit longer. Some that come to mind are the early Sansuis or even those Yamaha AX700s
Well i'm not the man you're asking but i'll throw my hat in the ring... pioneer a30 I'd say. Super simple but also doesn't use STKs, you can repair that thing no sweat and do it for nothing. And it's not some anemic thing either, still has some juice and very clean. Unfortunately there's no service manual online which is kinda lame. And I'm talking about the original one from the 80s, if you web searched pioneer a30 you'll find they've since made a new amp with the same name... ugh.
If you compare the before and after sound, it's night and day. The "before" sound was harsh and awful. I initially thought it was room echo and the microphone doing injustice. But the "after" sound made a huge difference. And I'm also inclined to consider rail voltage imbalance as the cause. But it would have been great to have tried it with a sine wave and a scope before fixing it.
About the switch, it can be a pain to source an appropriate one. And at $25-50 cost to your door, it probably would have cost twice as much as the market value of the unit. Good idea about swapping switches. I did the same on a Teac R2R swapping the speed switch for the 7/10" reel switch. After all I didn't use 7" reels much and with servo tension, the difference was minimal.
Oh yes it was night and day. Voltage imbalance to voltage amp the cause and likely the bad solder at the regulator. As to switches you are right in the cost and then there is the surprise when some dipshit at the supplier doesn't follow directions to mail parts and sends FedEx and they stick their 37.50 broker fee on top. Someone has sent me something for repair and they sent ur DHL. Fortunately DHL now requires payment of broker fees before they deliver. They are calling every day and i am not accepting. So eventually the person will get their unrepaired unit back with a bull for return shipping. FedEx just leaves it at the door and sends the bill 2 weeks later.
that clipping light is a nice feature even a lot of high end amps don't have that. i guess it monitors the speaker output for distortion? is is possible to add one to other amps that don't have it?
I think that the clipping light detects a DC component in the speaker output. Somw amplifiers had automatic safety features which disconnected the speakers
It has even copper shielding on transformer, not bad.
Back in the time when even relatively cheap products were well made
I had the opposite reaction to the flaw you found in the switch. Since you found the broken nub (seemingly in one piece), and since the amplifier isn't worth enough to chase down a replacement, and since you were going to swap the switch with an unbroken one that isn't used as much, my reaction would have been - let me see if I can repair the switch nub with some plastic glue. What would there be to lose, and even if it's a little more fragile, it won't be used all that often? After all, this repair was just for the fun of it anyway. Why not try the switch repair?
I have tried a similar thing on a Technics amplifier. The plastic glue did not support the pieces toghether enough and the switch was still kind of useless. It was a simpler switch and I was able to find a... kinda compatible replacement on aliexpress.
For the sake of testing, i have 5x panasonic small home theater speakers rated at 5ohm. Would i damage them or the amplifier if I were use them for testing when diagnosing an issue like this on any amp? Thanks for taking us on your journey to fix these things, really helps a novice like me.
This amp I believe will work with 4 or 8 ohms speakers
So 5 ohm no problem.
@@12voltvids will give it a try then. Thanks for your help!
Those switches are still available from alps. Got some spares here from last time I ordered some for a arcam amp.
I'm sure they are, but don't need the hi cut filter.
I have never seen the Voltage Amp IC mounted to the surface of the board like that. Every one has been vertical, I assume to help with cooling.
The flat one is likely just the preamp so won't be passing enough power to get hot
Do they use identical switches for the speakers and the filter ?
No totally different, you saw me using a crowbar to install it right. You know to make it fit. 😀
👍
Have you ever tried a solder sucker? I find it great and easy.
Yes I have one, I hate it. That's why I seldom, if ever use it.
I've had good luck with the gootwick brand one. I believe it's a rebadged Edsyn Solda-pult, or maybe a clone. Cost me $20 something from jaycar.
OMG now I know how push button switches with a locking mechanism work.
They're not actually all that complex, and can be repaired (Even without 3D printing the plastic bits, though that does make it easier these days), though they're fiddly to work on, but hey, if you can't get a replacement, what ya gonna do?
They work similar to the clicky ball point pen mechanisms.
I have a very similar AKAI that has the strangest problem: It sounds fine and works well, but when I turn it off it keeps playing for quite a few seconds (10 to 30 depending on the volume setting) and then clips and shuts off. Does anybody have a clue?
It seems your unit leaves the speakers connected on shut-down. Many amplifiers use a relay to disconnect their speakers during power on/off so this effect is not heard.
When the light comes on your driving the outputs into saturation put a scope on the outputs and you will see it 300 watt speakers would still do the same thing
I would have just left the spring off.
Your cat in this intro surely is pissed. I wonder what happened.
To my ears the akai dbx tape decks were the best, nakamichi are overrated
Nakamichi were junk but don't tell the enthusiasts that because they don't like to be told they wastes their money.
Uhhh, isn't this your FIRST ever amplifier?? It's worth fixing for posterity and nostalgia alone! Smh, you're talking about it like its just an old POS. lol. (it might be) But I would have thought it had a higher value to YOU?
Thats because it is an old POS
@@12voltvids LOL Fair enough. It sure is a special one though! ;)
@@Johnathan_Waters
Pretty basic unit. Fine for background music.
Ok come on. Clipping does not damage speakers. Over power does. Clipping sounds bad.
True. If you were to feed 25 watts of pure clean power through a 0.5 watt speaker, she cooked. But clipping still can damage a speaker, let's say a 15 watt speaker may be ok with 25 watts of clean power but 30 watts of clipping will make that speaker receive more of a DC voltage and the voice coil will have less air cooling and cook prematurely.
@@Thanson199415 What does it mean to feed power through a speaker?
Answer = poorly stated assertion. If you cause a 0.5w speaker to dissipate 25watts then yes it will burn. Clipping may mean an increase in DC at the load only if the amplifier has no output capacitor or if it is not transformer coupled. A direct ie- no cap output amp driving a load is a BAD idea, but even so if the clipping occurs in a balanced way at both rails, then there will be no increase in a DC component.
Clipping certainly does blow speakers. More so than over power.
I replaced drivers in a set of very expensive kef speakers more than once when the teenager if the house had a party when his parents were away and cooked the speakers with a 50 watt amp. The speakers rated 200 watts. The speakers however were the least of the kids worry. Even though they cost over $600 to repair that was nothing compared to the damage his friends did to the house. About 80,000 in damage.
@@12voltvids and so you were there with your triggered oscilloscope monitoring the situation as the kid did this, and you saw clipping? The 20w speakers driven by a 50w capable amp, gee what could go wrong?
You have a story, but I doubt it is correct.
@@12voltvids We got a troll 🤣
I hate sliding pots...
`They are kind of goofy aren't they?