SteveAndBell
1.21 Gigawatts
Hi all and Happy New Year!
I posted a quick vid on YouTube late last year showing my recently acquired AKAI M-8 Monoblocks in running order soon after I pulled them from the main cabinet: https://www.youtube.com/watch?v=U-zcXtBRpGM The rest of the machine was a bit of a basket-case as the alloy cam had crumbled and there were a few other major problems... but the Amps work perfectly :yes:
I have plans to box them up individually each with their own multi-voltage power transformer (found elsewhere in the Reel-to-Reel cabinet) allowing them to run either on their native 110V or our Aussie 240V and I've gathered the extra transformer & major parts required but haven't yet progressed due to holidays & having too many other things to do. As you can see my YouTube Vid received a comment from a 'Señor Minks' asking how to do this as he wants to do the same to his and as luck would have it I managed to find another M-8 locally with the exact same major problems and at a reasonable price so I nabbed it and thought it appropriate that I do a step-by-step guide on how to pull the Amps from these machines.
I've linked the YouTube video to this thread so hopefully 'Señor Minks' will join AK and reply with his progress as I go. I don't consider myself a technical whizz but have a basic understanding & respect of audio, electronics and Mains & HV Valve/Tube circuits so grab your popcorn and feel free to add your own comments to this thread along the way because this may help others do the same or similar in the future. Be patient though, for those in the know this obviously isn't a difficult job but this may take a while and drag on a bit.
OK, first thing's first, do not attempt this is you don't understand the dangers of mains potential voltages plus just as dangerous the stored energy of a HV capacitor. Make sure your home safety switch is fully functional (hit that TEST button!), never use two hands when working on live equipment (even put one behind your back!), take your time and you should be fine... but it's always healthy to be a little paranoid when working with this stuff as cockiness will get you dead real quick :sigh: Also, be aware that old gear like this may not have been powered up in decades so hitting it with full mains voltage can be bad for things like old & dry capacitors. It's always best to slowly power this stuff up with a Variac initially and always have a fire extinguisher at hand in case some goes 'pop' and crucifies itself in the process. Whatever you do, NEVER leave any gear in 'unknown' working condition connected to power when its unattended and in fact it's good practise to always unplug it whenever you don't need to have it powered up, even when you're still working on it! Safety first :thmbsp:
Righto, the first actual step... we need to test that the Amps work in their original form before we get hacking away at them. As per the pic attached it's best if you grab a couple of el'cheapo 6.5mm to RCA adaptors as this will allow you to connect a signal to the Line input sockets on each Amp much easier. I'm just using an old Smart Phone via RCA Cable for this as my home made test box accidentally got zapped when working on something else and is yet to be repaired While you're at it buy a cheap 6.5mm to 6.5mm audio lead (like a guitar lead), cut it in half, strip the insulation back to expose the conductors and use them as speaker leads connected to the Speaker sockets on the front of each Amp. Be sure to connect the Line-In signal and the Speakers before powering on and as per usual make sure the Volume controls are at minumum (all the way anti-clockwise). Also, these Amps wont make a peep unless the machine is in RECORD mode so while pressing the red button in turn the mode lever around to 'REC'.
OK, we're nearly ready to go for the fire-up. Check that your Line or Headphone Level signal source is actually working and the volume is up at maximum. Double-check your speaker connections making sure you have no short circuits and that the wires are properly connected at the speaker terminals. Check one last time that you have the unit in REC mode and those Volume controls are set to minimum then power it up! You should notice the tubes glow after a few seconds but leave it for another 20-30 seconds to ensure they're properly warmed up then slowly turn the Volume up on each Amp. Hear anything? If so, slowly continue adjusting the volume up and up and you'll hopefully have yourself sweet, sweet music
If not there are many things that could be preventing this but we wont know how to start troubleshooting until you tell us what the problem is. An example on my original units was that one of the big slider switches that's activated when the REC mode is set was faulty on my Right channel Amp. A few seconds poking around with a small plastic rod found that straight away and pressing on it firmly got it working fine and that was all I needed to prove all was OK at this stage. My 2nd M-8 (pictured) has a different problem, the Right channel Amp isn't Amplifying the input and just makes all sorts of strange humming & pulsing noises when the Volume is turned up past a certain point. Tapping into the 5-Pin DIN connector on the side of the cabinet I managed to get it to amplify the music I was feeding it so again that's all I need to know at this stage but good to keep in mind for later.
So 'Señor Minks', can you get yours to this state and if so how does it sound?
I posted a quick vid on YouTube late last year showing my recently acquired AKAI M-8 Monoblocks in running order soon after I pulled them from the main cabinet: https://www.youtube.com/watch?v=U-zcXtBRpGM The rest of the machine was a bit of a basket-case as the alloy cam had crumbled and there were a few other major problems... but the Amps work perfectly :yes:
I have plans to box them up individually each with their own multi-voltage power transformer (found elsewhere in the Reel-to-Reel cabinet) allowing them to run either on their native 110V or our Aussie 240V and I've gathered the extra transformer & major parts required but haven't yet progressed due to holidays & having too many other things to do. As you can see my YouTube Vid received a comment from a 'Señor Minks' asking how to do this as he wants to do the same to his and as luck would have it I managed to find another M-8 locally with the exact same major problems and at a reasonable price so I nabbed it and thought it appropriate that I do a step-by-step guide on how to pull the Amps from these machines.
I've linked the YouTube video to this thread so hopefully 'Señor Minks' will join AK and reply with his progress as I go. I don't consider myself a technical whizz but have a basic understanding & respect of audio, electronics and Mains & HV Valve/Tube circuits so grab your popcorn and feel free to add your own comments to this thread along the way because this may help others do the same or similar in the future. Be patient though, for those in the know this obviously isn't a difficult job but this may take a while and drag on a bit.
OK, first thing's first, do not attempt this is you don't understand the dangers of mains potential voltages plus just as dangerous the stored energy of a HV capacitor. Make sure your home safety switch is fully functional (hit that TEST button!), never use two hands when working on live equipment (even put one behind your back!), take your time and you should be fine... but it's always healthy to be a little paranoid when working with this stuff as cockiness will get you dead real quick :sigh: Also, be aware that old gear like this may not have been powered up in decades so hitting it with full mains voltage can be bad for things like old & dry capacitors. It's always best to slowly power this stuff up with a Variac initially and always have a fire extinguisher at hand in case some goes 'pop' and crucifies itself in the process. Whatever you do, NEVER leave any gear in 'unknown' working condition connected to power when its unattended and in fact it's good practise to always unplug it whenever you don't need to have it powered up, even when you're still working on it! Safety first :thmbsp:
Righto, the first actual step... we need to test that the Amps work in their original form before we get hacking away at them. As per the pic attached it's best if you grab a couple of el'cheapo 6.5mm to RCA adaptors as this will allow you to connect a signal to the Line input sockets on each Amp much easier. I'm just using an old Smart Phone via RCA Cable for this as my home made test box accidentally got zapped when working on something else and is yet to be repaired While you're at it buy a cheap 6.5mm to 6.5mm audio lead (like a guitar lead), cut it in half, strip the insulation back to expose the conductors and use them as speaker leads connected to the Speaker sockets on the front of each Amp. Be sure to connect the Line-In signal and the Speakers before powering on and as per usual make sure the Volume controls are at minumum (all the way anti-clockwise). Also, these Amps wont make a peep unless the machine is in RECORD mode so while pressing the red button in turn the mode lever around to 'REC'.
OK, we're nearly ready to go for the fire-up. Check that your Line or Headphone Level signal source is actually working and the volume is up at maximum. Double-check your speaker connections making sure you have no short circuits and that the wires are properly connected at the speaker terminals. Check one last time that you have the unit in REC mode and those Volume controls are set to minimum then power it up! You should notice the tubes glow after a few seconds but leave it for another 20-30 seconds to ensure they're properly warmed up then slowly turn the Volume up on each Amp. Hear anything? If so, slowly continue adjusting the volume up and up and you'll hopefully have yourself sweet, sweet music
If not there are many things that could be preventing this but we wont know how to start troubleshooting until you tell us what the problem is. An example on my original units was that one of the big slider switches that's activated when the REC mode is set was faulty on my Right channel Amp. A few seconds poking around with a small plastic rod found that straight away and pressing on it firmly got it working fine and that was all I needed to prove all was OK at this stage. My 2nd M-8 (pictured) has a different problem, the Right channel Amp isn't Amplifying the input and just makes all sorts of strange humming & pulsing noises when the Volume is turned up past a certain point. Tapping into the 5-Pin DIN connector on the side of the cabinet I managed to get it to amplify the music I was feeding it so again that's all I need to know at this stage but good to keep in mind for later.
So 'Señor Minks', can you get yours to this state and if so how does it sound?