Hello there!
I've been visiting this community for some time now, but this is the first time I've ever needed to post, so allow me to introduce myself briefly. I work as a guitar tech in Spain and I record and produce my own music. I recently acquired an Akai 4000DS MKII reel to reel that I plan to use in my production chain, add color to certain tracks, echo, mastering and even some live recordings. I know this deck is not quite there at the HIFI spectrum, but that's why I got it.
I'm still waiting for it to arrive, but I'm already preparing the mod. It's an american 120V 60Hz unit, but we use 220V 50Hz in Spain. I could use a step down transformer but they're pricey and too big. The smaller adapter plugs seem very sketchy to me and I just don't trust them. To me, it makes more sense to convert the unit itself, it will only be used in Spain (or Europe if I ever sell it).
I have experience repairing and modding simple electronics, but it's not my area of expertise, so I'd rather just ask. I looked at the schematics and it seems to me that the only difference between models is the powerboard, which basically has only different transformer. There's a scrapper around here that will sell me an original european transformer for cheap. My question is, do I need to replace anything else in the deck or will it work fine if I just swap one transformer for the other?
In this schematic, down to the left the transformer my unit has (TI LET-19), and to the right of it, the transformer I'd need (TI LET-17). It looks like everything else is pretty much the same, except maybe having to replace the fuses and remove the little cap following the power cord? Any insight would be greatly appreciated!
In any case, will keep you posted with the progress of the mod and will add pics in just so if in the future has this same issue, they have an easy page to refer to.
Thanks a lot!
I've been visiting this community for some time now, but this is the first time I've ever needed to post, so allow me to introduce myself briefly. I work as a guitar tech in Spain and I record and produce my own music. I recently acquired an Akai 4000DS MKII reel to reel that I plan to use in my production chain, add color to certain tracks, echo, mastering and even some live recordings. I know this deck is not quite there at the HIFI spectrum, but that's why I got it.
I'm still waiting for it to arrive, but I'm already preparing the mod. It's an american 120V 60Hz unit, but we use 220V 50Hz in Spain. I could use a step down transformer but they're pricey and too big. The smaller adapter plugs seem very sketchy to me and I just don't trust them. To me, it makes more sense to convert the unit itself, it will only be used in Spain (or Europe if I ever sell it).
I have experience repairing and modding simple electronics, but it's not my area of expertise, so I'd rather just ask. I looked at the schematics and it seems to me that the only difference between models is the powerboard, which basically has only different transformer. There's a scrapper around here that will sell me an original european transformer for cheap. My question is, do I need to replace anything else in the deck or will it work fine if I just swap one transformer for the other?
In this schematic, down to the left the transformer my unit has (TI LET-19), and to the right of it, the transformer I'd need (TI LET-17). It looks like everything else is pretty much the same, except maybe having to replace the fuses and remove the little cap following the power cord? Any insight would be greatly appreciated!
In any case, will keep you posted with the progress of the mod and will add pics in just so if in the future has this same issue, they have an easy page to refer to.
Thanks a lot!
I'll give your thread a bump by saying that C1 is there simply to suppress sparking across the switch contacts.
However, for safety reasons, I won't comment on the viability of the transformer substitution.
The transfomer has a dual primary.
Wired as shown, they are in parallel.
Simply wire them properly in series.
Wired as shown, they are in parallel.
Simply wire them properly in series.
Besides the transformers, the circuitry connected to the motor and tension switch through J7 / P7 is slightly different in all three versions. They do not appear to be interchangeable. Look at the pin out of the J7 / P7 connection for each version.
Perhaps the motor too, but I can't find the motor as a separate item in the parts list.
So I think you need to get the whole motor block assembly from the scrapper too.
Perhaps the motor too, but I can't find the motor as a separate item in the parts list.
So I think you need to get the whole motor block assembly from the scrapper too.
Also, if wiring it to run on 240V at 50Hz, the capstan belt needs to be shifted on its smaller-side of the flywheel and motor shaft pulley.
Otherwise the speeds will be off.
I own the 4000D, basically the same machine, and they all have the 50/60Hz belt option.
Otherwise the speeds will be off.
I own the 4000D, basically the same machine, and they all have the 50/60Hz belt option.
Actually, in the notes on the right hand side of the page, #4 says the transformer block and motor block are different for each area.
So you need both.
So you need both.
That was my initial idea! The american transformer has two 120V primaries and it seemed to me that wiring them in series would allow for 220V use (240V really, but that's within ok), do you think it would work?
I saw that and I agree, but at the same time, I don't think there's more than one kind of motor, even looking at parts in eBay I can't find two motors that are different across all MKI and MKII models, so is the motor really different?
I haven't had the chance to open up the deck yet as I still don't have it with me, but maybe the power block and motor block was factory designed to be a one single unit and that's why the whole thing would change depending on area. I don't know, I can't be sure, but it certainly looks like the motor is always the same, maybe not the few caps and resistors surrounding it, though. Rebuilding that small circuit wouldn't be much of a hassle, I think.
About this, I'm a little confused at how current talks to both the transformer and motor in the european model. In both models it's the second primary that talks to the motor, but in the european one, the second primary only talks to the motor, while in the american model they seem to be somewhat linked together through the J7/P7... With the slight differences in caps and resistors around the motor, I guess the motor always expects to see the same voltage, that's why the components around it vary from one model to another, right? I'm just circling around the question of "is the motor really the same?" but I think it is.
Thanks a lot everyone for your answers so far! It's been really helpful, I can see the light at the end of the tunnel now. Let's see if I get lucky and someone has done a similar job to one of these or another deck, maybe I can clear up some more questions. Meanwhile, I'll get ready a post with a mod I've recently finished on an old italian electric organ, it's sounding sweet.
Lots of love!
The actual motor may be the same for each, but the "Motor Block" is not. From the schematic, the motor block consists of the motor, the tension switch, some capacitors and resistors. This "block" or assembly, has a plug (P7) on it, which plugs into the jack (J7) on the power board. The pin connections are different for each version, so even if the connectors from different versions fit together, it won't function correctly and could cause damage.
As for the motor power, with the LET-17 and LET-19 transformers, it comes from the BLU - GRN coil which is actually a secondary winding.
The primary of the LET-18 transformer functions as an auto-transformer and the motor power comes from either the 100V GRN tap or the 120V YLW tap, depending on the positon of switch SW 8, and the RED common tap.
As for the motor power, with the LET-17 and LET-19 transformers, it comes from the BLU - GRN coil which is actually a secondary winding.
The primary of the LET-18 transformer functions as an auto-transformer and the motor power comes from either the 100V GRN tap or the 120V YLW tap, depending on the positon of switch SW 8, and the RED common tap.
So the mod is slightly more complex than I anticipated, but it is still doable, isn't it? My scrapper guy said I'd only have to swap the transformer, but I really didn't think so.
Thanks!
Thanks!
Congrats on getting the 4000ds Mk II. I have the same exact deck and recently repaired the power supply thanks to the help from some of the people on this forum.
On the suggestion of one of them, I also replaced all of the 458 transistors with modern KSC1845 transistors. This made a BIG improvement, and I highly recommend it. It seems that much of the "tape hiss" of reel to reel decks is the hiss from crappy 1970s transistor preamp circuits. At 7.5ips, there is very little hiss and it sounds awesome with these transistors. You want the sound of tape, not transistors. Just be careful -- it's easier to clip the old transistor and pull the legs out one at a time. If you don't have a 7.5ips capstan sleeve, PM me.
This deck is in the perfect sweet spot: sounds like tape enough to add color to your recordings, that tape kind of distortion on cymbals and natural compression, and fun to use, something "special" to tape live and talk about with people. But not too good, because if you can't tell the difference from digital, it's just a waste of money on tape.
Have fun and good luck.
On the suggestion of one of them, I also replaced all of the 458 transistors with modern KSC1845 transistors. This made a BIG improvement, and I highly recommend it. It seems that much of the "tape hiss" of reel to reel decks is the hiss from crappy 1970s transistor preamp circuits. At 7.5ips, there is very little hiss and it sounds awesome with these transistors. You want the sound of tape, not transistors. Just be careful -- it's easier to clip the old transistor and pull the legs out one at a time. If you don't have a 7.5ips capstan sleeve, PM me.
This deck is in the perfect sweet spot: sounds like tape enough to add color to your recordings, that tape kind of distortion on cymbals and natural compression, and fun to use, something "special" to tape live and talk about with people. But not too good, because if you can't tell the difference from digital, it's just a waste of money on tape.
Have fun and good luck.
Last edited:
Yes, I think so. Changing both parts is what the factory does to regionalize the deck anyway, according to the service manual. So your modified deck should meet all the original specs, especially for speed accuracy, which is critical for compatibility with other decks.
Best of success!
I'm sure you're right, but for the OP's purposes, maybe even using the deck on a "unique" playback speed of its own is not a problem. 🤔
Many people use these decks in such a way that what they record will never be played back on another deck. It's not for listening to commercial recordings, and speed can be tweaked in digital mastering anyway. Just a suggestion if the modification is difficult.
I thought of running my deck at approximately 10ips.
A tape recorder that is "off-speed" will also exhibit a difference in audio response due to not being biased for said "off" speed.
That is why seperate internal calibrations/adjustments are used for each proper speed.
That is why seperate internal calibrations/adjustments are used for each proper speed.
That's true. But on the 4000ds mkii it's just an EQ switch for the two speeds and I tend to use the 3.75 setting even on 7.5 for the extra high end, because it needs it. HF response depends on the tape and a lot of other factors IME. I interpreted the OP as using it as a creative tool more than something to be calibrated precisely... I'm just throwing that suggestion out there, that if extra mods are all for a 10% tape speed difference or need hard to find parts, it might not be worth it. Up to the OP.
Great! Thanks for the tip! Looking for info on the deck I stumbled across your post a few days ago, I'll read it more thoroughly once I get mine. I will keep the transistors in mind for sure, I'd rather do all the surgery at the same time once I open it up.
Alright! I'm more optimistic now, I'll take a good look at it, see what's really different around the transformer compared to the european unit and change those parts. I've researched a little more and it seems like the motor is always the same, but a few components change, which I hope won't be a headache.
About the speed, I initially thought I didn't care if my speeds were off, as I'd record and play everything with this one deck, but thinking about it, I'd rather have it to work correctly. Maybe one day I'll need to play someone else's tape, or maybe my deck will blow up for some reason, it'd be an incredible pain in the derriere to recalibrate a different deck to some random off speed, so I'll just try to keep it as stock as possible in that sense. I'd love to add some speed mod with a switch and pot though, so I can make it go super fast or hyper slow on purpose, but that will come later.
Thanks everybody!
@fernandito "I'd love to add some speed mod with a switch and pot though, so I can make it go super fast or hyper slow on purpose, but that will come later."
Not unless you're willing to get very complex and custom-design an appropriate electronic servo control and a completely different motor.
It's simply not a simple "switch and a pot" idea, sorry.
Besides, that borders on butchering the deck up beyond reason.
If you want fancy features, go for a deck that already has such controls.
Not unless you're willing to get very complex and custom-design an appropriate electronic servo control and a completely different motor.
It's simply not a simple "switch and a pot" idea, sorry.
Besides, that borders on butchering the deck up beyond reason.
If you want fancy features, go for a deck that already has such controls.
Agreed! Especially considering I just unpacked my unit and it's quite in impressive good condition. I expect some electronic cleanup will have to be done but it looks good on the outside. The plywood is slightly chipped here and there but it's alright. Next step is opening it up, checking the whole powerboard and planning how to proceed with the voltage conversion. Thank you!
Hello there!
I've been disassembling the unit, cleaning parts, cleaning the pcb's, etc. It seems to be in decent shape to my untrained eye. I looked at the motor block and it expects to see 100V at 50-60Hz, so, comparing the different area models, I think it's safe to say the motor's always the same. If you look at the components surrounding it, R12 and C7 are present in both models, meaning, the massive silver can cap and the big cement resistor attached to the motor are always there.
However, in the CSA american version there's just C7 (2uF 250V) and R12 while, in the CEE european version, C7 is drawn with a discontinued line making a square around a 2uF and 0.5uF 300V caps in paralel. This means I can keep the same cement resistor but the silver can cap should be replaced by the CEE version to ensure the motor receives the voltage it wants.
Apart from that, there's another difference. In the CSA version, the tension switch is wired directly to the main power switch, but in the CEE version it's wired directly to the motor, with CR1 in paralel. I assume CR1 is another kind of enclosure containing a 0.1uF 500V cap + 120K resistor in series, but I couldn't find it in the parts list. Does anyone know why this is like that? I can wire a cap and resistor to the switch without a problem, but I'm curious to know why in one model it's wired to the main power switch and in the other it's wired directly to the motor with CR1 in paralel.
If I've understood correctly, the changes I'd have to make would be:
I'd also like to know why in the CEE Version, the main power switch SW6 has no fuse. I believe in the CSA Version there's a fuse right after AC in case an idiot like me plugs it into a 220V outlet. Wouldn't the CSA Version also be safer with a regular fuse in case of a power outage, a power spike or something like that? I'd throw in a fuse in there aswell if that was the case.
Another question that pops into my mind is, would this unit benefit from a 3 core plug with ground? The BSI model is for 240V and it's shown in the schematic how it was manufactured with a 3 core plug. Seems to me that a 220V unit could also use it for safety reasons and also to potentially eliminate unwanted noise? I could wire the whole thing as shown in the CEE Version and solder a third core to a common ground. I have to replace the cord anyway, as it comes with the american plug, so I'd rather do the whole thing at once.
Thank you!
I've been disassembling the unit, cleaning parts, cleaning the pcb's, etc. It seems to be in decent shape to my untrained eye. I looked at the motor block and it expects to see 100V at 50-60Hz, so, comparing the different area models, I think it's safe to say the motor's always the same. If you look at the components surrounding it, R12 and C7 are present in both models, meaning, the massive silver can cap and the big cement resistor attached to the motor are always there.
However, in the CSA american version there's just C7 (2uF 250V) and R12 while, in the CEE european version, C7 is drawn with a discontinued line making a square around a 2uF and 0.5uF 300V caps in paralel. This means I can keep the same cement resistor but the silver can cap should be replaced by the CEE version to ensure the motor receives the voltage it wants.
Apart from that, there's another difference. In the CSA version, the tension switch is wired directly to the main power switch, but in the CEE version it's wired directly to the motor, with CR1 in paralel. I assume CR1 is another kind of enclosure containing a 0.1uF 500V cap + 120K resistor in series, but I couldn't find it in the parts list. Does anyone know why this is like that? I can wire a cap and resistor to the switch without a problem, but I'm curious to know why in one model it's wired to the main power switch and in the other it's wired directly to the motor with CR1 in paralel.
If I've understood correctly, the changes I'd have to make would be:
- Replace Transformer LET-19 for LET-17
- Replace C7 for the CEE Version C7
- Rewire Tension Switch SW5 to the motor and add CR1 in paralel
- Replace CSA Version fuses for CEE Version fuses
I'd also like to know why in the CEE Version, the main power switch SW6 has no fuse. I believe in the CSA Version there's a fuse right after AC in case an idiot like me plugs it into a 220V outlet. Wouldn't the CSA Version also be safer with a regular fuse in case of a power outage, a power spike or something like that? I'd throw in a fuse in there aswell if that was the case.
Another question that pops into my mind is, would this unit benefit from a 3 core plug with ground? The BSI model is for 240V and it's shown in the schematic how it was manufactured with a 3 core plug. Seems to me that a 220V unit could also use it for safety reasons and also to potentially eliminate unwanted noise? I could wire the whole thing as shown in the CEE Version and solder a third core to a common ground. I have to replace the cord anyway, as it comes with the american plug, so I'd rather do the whole thing at once.
Thank you!
Don't forget the conversion from US to EU is not only voltage change but also mains frequency change. Probably the flywheel belt has option for 60/50 Hz run.
Yes, absolutely! This unit doesn't have a frontal knob to control the Hz input. It does say in the back it's a 120V 60Hz unit, but the motor itself runs at either 50/60Hz, so I guess the transformer (and other parts) swap compensates for that somehow? Maybe there's some adjustable switch inside of the unit I haven't seen yet. I will definitely explore this question further in the service manual, thanks for bringing my attention to it!