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Akai GX-4000D

Stereo Reel to Reel Tape Recorder (1978-85)

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Akai GX-4000D


The Akai GX-4000D features include a 4-track stereo and monaural recording/playback system, Twin VU meters for indicating recording and playback levels, Recording indicator lamp, Recording safety button, Monitor selector switch, Sound on sound recording procedure, Microphone jacks and Microphone recording level controls.


Track system: 4-track, 2-channel, stereo/monaural system

Heads: 1 x GX playback, 1 x GX record, 1 x erase

Motor: 1 x 4-pole induction motor

Reel size: up to 7 inch reel

Tape speeds: 3 34  7 12 ips

Wow and flutter: 0.08% (7 12 ips)

Frequency response: 30Hz to 24kHz (7 12 ips)

Signal to Noise Ratio: 60dB

Total harmonic distortion: 1%

Input: 70mV (line), 2mV (DIN), 0.25mV (mic)

Output: 0.775V (line), 0.3V (DIN)

Dimensions: 440 x 315 x 230mm

Weight: 13.2kg


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Reviewed Mar 16th, 2018 by vladimirescu

With a very reliable mechanics, this recorder benefits the latest year '80 modernization of the AKAI technicians. Playback and recording is so fidelity as a semi-professional tape recorder of the 600 series has.

Reviewed Apr 17th, 2017 by crisenna


Reviewed Nov 09th, 2015 by dorucraciun


Reviewed Aug 13th, 2014 by szandor6911

I recently bought an Akai gx 4000d for only 20 dollars but it seems the capstam sleeve is not on the front so i took the head cover off and found one device that does twist off and does fit the capstam but i just want to make sure its the right one. Can someone please explain or better yet upload a pic of exactaly where it would be at? This is my first reel to reel and I am not even sure how to put the reels in,can someone also upload a pic of the head cover off and tape going through it so i can see it? I tried downloading the manual but it is not downloading for some reason,thanks for any help on this.

Reviewed May 05th, 2014 by guix3212




re: GX-4000D

Hello everyone, this place is fantastic.

I just entered this world of reel to reel with a GX-4000D, but I find a small problem at 7 1/2 ips. As the tape advances slightly more than half the coil, it seems that they have no force and stop. In 3 3/4 it is not appreciated, but at fast speed it occurs in reading / recording as well as in forward / backward movement.

Is it possible with a belt change to be solved? If so, someone can help me and tell me if to change the strap it is necessary to remove the front cover also or only with the back and top is enough.

Thank you very much, all help will be well received. It's my first tape recorder and I'm a bit lost.


I have been working on fixing up one of there and after getting it to finally record the recordings are tainted by a vibrato type effect, It sounds super cool but there is clearly something wrong... any thoughts??

re: vibrato

Is your S.O.S. (sound-on-sound) function on? Turn it off.

re: vibrato

It’s probably what they call wow and almost all recordings on tape have some degree of it. Older tape machines tend to have more wow, especially on lower recording speeds, cassette can be even worse than reel to reel in my experience because it is recorded at 1 7/8 IPS (inches per second) while most reel to reels record at 3 3/4 or 7 1/2 IPS. Proffesional recording decks most often record at 15IPS and 30IPS (some do 7 1/2 as well) which produces significantly less wow and “flutter” which is the tremolo like effect created by the sound of the tape cutting in and out very quickly. Wow on the other hand is that wobbly pitch variation effect that you hear on tape recordings. Depending on how much wow your hearing on your machine, there could be potential problems if it’s an extreme amount of wow, so much so that it’s really distracting from the recording. The potential things that could be causing the wow are to numerous to speculate but it could be nothing at all is wrong. I don’t actually own this particular machine so I can’t say how much is normal but I hope this helps. Maybe search YouTube for this model and see how other people’s units sound in comparison.

GX-4000D VU Meter Lamps

One of my VU meter lamps has failed. Is it correct that the meters for the GX-4000D are sealed, so that the bulbs cannot be replaced?

re: GX-4000D

I have purchased a GX-400D and discovered the VU Meter lamps don't work. I have checked power and 7.5v AC appear at the VU meter so power OK. VU meters seem to be sealed units so question is "how do I change the lamps"?

re: GX-4000D

Thank you for creating this forum. My unit has such sentimental value (I inherited from my mother since her passing) .
This issue arose about two weeks ago. My right tape reel spins for approximately 2 minutes then it slows down and comes to a complete stop. Also, there's squeaky noise coming from the motor. Would you be able to provide some insight on how to repair?

karodimitrov's picture

re: GX-4000D

I thing you must clean all tape mechanism.Same and for the pinch roller.Check too if no cracks in the rubbers and if necessary-replace them.Check the motor for radial play and lubricate it.If the play is too big,afraid motor is gone.But it's difficult to give you an answer from first post here.
It would be better if you check and tell me and i'll thing about it and tell you....:)))
P.S.The rubber should be soft when pressed with a fingernail and free of grease.
Same for the belts.Clean all them with alcohol (pinch roller too).

re: GX-4000D

Hi all

I have just perceived a black GX-4000D in a rather good state with 6 Maxell professional 7" recorded tapes.
After cleaning the deck on the outside and rubber wheel, and solving a crackling potmeter tested the sound with AKG headphones: Not bad but i hear some reverbs in treble maybe because the tapes are old recordings. Treble is also some hissy and it lacks some bass. Seems to sound some coloured in midbass, mids are very clear. Heads should be cleaned also and demagnetised.

After several tapes with good stereo sound i decided to revive this tapedeck. Downloaded schematic and the audio circuit is rather simple. Adjusting the heads would be not easy and i will leave this part first, as i guess this would fit best to the tapes i have with it.

So what parts should be replaced? I think of coupling caps an filter lytics. Other tips?
Have a casettetape demagnetiser but that way to small for these huge heads :)

karodimitrov's picture

re: GX-4000D

The best way to demagnetizing is using inductive soldering iron.Just pull the trigger and approaching his transformer to the heads without touch them,then remove it.Several times by this way and heads be OK.This method helps me many times.It works too for old TV screens (to demagnetizing).Check too electrolytic capacitors in preamlifier-they are old and may be screwed.Replace them.C27,C28,C31,C34,C35,C36.Pay particular attention to C22, C27 andC34.
Now I remember for a SONY TC-K-terrible sound-if you can call this "sound".After demagnetizing using aforementioned method-WOW...Its safety-don't worry.I never use casettetape demagnetiser-this works better.

re: GX-4000D

Hi, I have one of these on the bench at the moment. No sound from Playback or Source input. traced audio through input preamp circuit to TR5 but no output to headphones or rca outs. Changed the caps above but no joy. any ideas? Thanks

karodimitrov's picture

re: GX-4000D

Check "Tape-Source" switch and clean it well.

karodimitrov's picture

re: GX-4000D

Monitor selector.

re: GX-4000D

Thanks Karodimitrov for help.

Had checked the schematic for coupling caps and found 12 in each channel. Will replace them for standard but good stuff. Philips blue lytics i prefer above black gate exotic rubbish, Marcons and Nippon Chemicons are fine too.

Just cleaned the heads and they where rather clean allready. Played a tape and pressed some on the heads and on the tape gently. The sound became worse, more dull so the adjustment is fine.

The sound is very good allready and am pleased with this deck, will play around with it. The better recordings in special are fine in sound, treble sounds fine, no echoes/reverbs (eg JJ Cale's Troubadour album from vinyl recorded)
Think deck was parked a long time it had to burn in some, in a while the coloured sound dissapeared allmost completely.

Matter of fact i have a C shaped coil on mains supply with pulse switch which i use as tool demagniser. Will try to demagnitise with that tool. (reels away please.. :D )

karodimitrov's picture

re: GX-4000D

This deck is great machine and I think you will enjoy its perfect sound for a long time.
But is advisable to demagnitise the heads(use your coil or whatever it is),because even the deck has built in demagniser(some models of decks have such),sometimes he can't help.
And make this regularly while you are together...:D)
Regards and good luck...fan of AKAI.

re: GX-4000D

Dear Sirs,

I am seeking for GX-4000D, or GX-4000DB-R.

Can You help me? What is the price?

Thank You in advance

re: GX-4000D

I have two GX-4000D units and I am very happy with both. The prices I've seen are quite varied. They go for around $100.00 to $500.00 and up. It all depends on the care that the unit received over it's lifetime. You must also be aware that these units are vintage and some replacement parts are hard to find. Be careful where and who from you purchase your unit. The only downside, I am aware of, is it only has two speeds. Good luck!

re: GX-4000D

I have both new belts for my GX-4000D recorder but looking at the service manual it would appear that you have to remove every side panel, front panel, back panel etc. to change the main drive belt (no problems with the counter belt). Isn't there a way to change the main drive belt without having to disassemble the entire unit ??


re: GX-4000D

I am not a tech but I have changed the belts on two GX-4000D units. Try not to be intimidated. It was a slow process but I did it without any problems. If you follow the repair manual, it will help you greatly. Good Luck!!

re: GX-4000D

Thanks many times for the site and all the great information

GX4000D transistors

I have had my GX4000D for many years and, about five years ago, it started getting non-specific failures such as one channel quiet or distorted or recording unbalanced. I resoldered all the transistors and this helped but didn't cure the anomalies.

I read on many threads that the 2SC458 transistors made during the time of the assembly of the tape recorder had a poor reputation - prone to early failure, leakage or noise - so I took the thing apart and replaced all the 2SC458 transistors (16 of them) with newer equivalents. I left the 2SC945 transistors (8 of them) because they tested OK and didn't have the same poor reputation.

I had to reset all the record, playback and UV meter levels with the help of a tone generator and the net result has been perfection. Nice clean sound, balanced and distortion free. I should have done it 5 years ago.

re: GX4000D transistors

Hi there, I have recently acquired a GX4000D and I think it has the same problem. Could you please let me know the number / name of equivalent transistor that you used? Kind Regards - Annie

Mic Input Distortion

Just picked up one of these machines and I noticed that the left mic input is very distorted. Right input sounds great. I'm new to analog recording and this is my first machine so I'm hoping there is an easy fix for this. Is this problem likely to be caused by a bad connection or maybe the jack just needs to be cleaned out a bit? What would I use to clean it if that was the case. Any help is very much appreciated.


Akai GX4000DB

I have recently acquired an Akai GX4000DB which records fine but plays back on one channel. I took the front plate off and sprayed the tape/monitor switch with contact cleaner and found the other channel plays back when the switch is depressed - hence I can get one channel playing back in the Tape and the other in Monitor position. Does anyone know the part number of the tape/monitor switch and where to get one from. Also I note that the capstan sleeve and top nut is not present. Any help welcome



Akai 4000d

Hi All.
Can someone please advise. I have just bought an Akai 4000d to play my old tapes from the 70's It plays fine, however the switch to change tape speed does not work. Is this a belt problem, electris switch or could it be either.

re: Akai 4000d

You have to use the captan adapter to play at a different speed

GX-4000D Tape Speed

The capstin drive, that holds the tape against the pintch roller, has a bknurled screw top.
Unscrew Counter clockwise, and remove the speed change sleeve, screw the knurled screw back on, so you won't lose it and the sleeve is stored under the head cover, carefully pull it straight up and put sleeve on the storage post there.
That's it.

Swissaudio Uruguay's picture

Akai 4000 speed change.

Hello! The key does not change the speed. Only changes the bias and equalization. If you want to change the speed, you must change the diameter of the capstan removing (9.5) or placing (19) screw on the capstan. The screw thread is reversed. Carefully and good luck!

I also have the Akai 4000d

I am having the same problem as well, I am not sure what is causing the problem, but now I know it might be something inherited with the akai gx 4000d if and when you locate the problem please let me know as well, I have a lot of old tapes I used to listen to and can't right now.


Swissaudio Uruguay's picture

Akai 4000 speed change

Hello! The key does not change the speed. Only changes the bias and equalization. If you want to change the speed, you must change the diameter of the capstan removing (9.5) or placing (19) screw on the capstan. The screw thread is reversed. Carefully and good luck!

Akai 4000D speed problem

Hi David , the speed on these akais is changed by sliding a sleeve over the capstan not by the switch ,the sleeve and nut are located above the head cover (4000D) or under it (GX4000D) the switch only alters the equalisation . Hope this helps .

What a time capsule

It's rather incredible that both these manuals survived enough decades to arrive here for those of us who come across a machine that survives a few decades. A rather chaotic path all must have taken, much cudos to those who preserved the documentation. The internet contains a lot of white noise, but these nuggets remind me why I still use it (if not mp3's...)


Manual definitely clarified some of the finer points of use.. but that service manual allowed me to repair the mechanics of the thing. I believe there is still much fine tuning of it in the future, but now I'm listening to transcriptions of records my grandfather made during the 60's in the Marshall islands.

Anyone know where to get outer capstan should I run into speedier tape? I found measurements so I might just fabricate it if I run into the need...

I just recently boug

I just recently bought a black model gx-4000d off of e-bay,
runs smoothly, however when it records, the level is dramatically
lower than what it is set at with the monitor, and it tends to
distort with high frequencies.
Can anyone help?
machine tassimo

Akai Model GX4000 D - Reels from late 50s / early 60s

Intrigued to hear you are listening to recordings made by your grandfather in the 1960s. We do have a set of recordings here, some from the mid-50s, some from the early 60s. I have been offered an Akai GX4000 D. Would that allow me to listen to these early recordings as the machine features "4-Head" technology which presumably was not available in the 50s/early 60s. In fact, one does not know what recording technology was used to produce these tapes - presumably very basic mono recording... How did you manage with your grandfather's tape reels?

1960's tape recorder

I was just reading your post about having recordings made in the early 60's. I had a 4 track recorder (don't know the make now) in 1960. I did some personal recording of oral histories of my family at that time. A few years ago, I got hold of a 4 track (again, don't know what kind) at a yard sale and tried to find these family recordings on the pile of tapes I have in a box. Couldn't find them. I am still wanting to find them so I just bought an AKAI GX4000D on ebay to try it again. Hasn't arrived yet but am looking forward to it. Anyway, it's amazing how well the tapes remain in such good condition after all this time. And, they did make 4 tracks in the early 60's. You probably got your tape deck by now. How did it work out?

Gx4000 D reels

I believe these were made from 2nd half of the 60's into the 70's. I don't have specifics other than my uncle's memory of his father during his couple of years he lived in the islands before college. Some of the reels are commercial (Schumann's 3rd being my current favorite) while others are mixes with the track listing in Norwegian in which I can only pick out the basics. (Say the Russians tape which starts with a quartet by Tchaikovsky, then Borodin, followed by a symphony of Borodin and Prokofiev.) I have a feeling many were made early 70's (back in the US) because his latest record player was a Dual 1219 produced from 70-72, though I'm sure he had turntables before that. Everything I've played has been stereo. Oddly, I've come across tapes at the faster speed though the outer capstan appears to have been separated from the player for many many years. I have around 40 (?) of these reels in toto, most of which I haven't had the chance to listen to. Currently I'm trying to fix a tube amp I've modified from a kit, so it might be a little while before I'm running again. I'll let you know if I get more specific information.
I can't see why this player wouldn't handle older reels as long as the tape speed matched, though Hawaiian music at half speed is good for laughs.


thank you very much for this site

amirrosi's picture

akai GX-4000D

thank you very much for this site

akai gx-4000d

I just recently bought a black model gx-4000d off of e-bay,
runs smoothly, however when it records, the level is dramatically
lower than what it is set at with the monitor, and it tends to
distort with high frequencies.

Can anyone help?


Clean and demagnetize heads. Clean also pinch roller. Your problem will be solved, i hope.
Best Regards,


Clean and demagnetize heads. Clean also pinch roller. Your problem will be solved, i hope.
Best Regards,

1st off clean and

1st off clean and DE-MAGNETIZE the heads. As these machines get older the recording levels get a bit lower than the source level. Adjust the levels accordingly. Other than that there isn't much you can do unless you send it in to a shop and have them go over it, which considering it's age isn't a bad idea.

The model you've got is probably a 4000DS not a GX-4000D. the GX-4000D is a later model and is silver faced only.

GX-4000D black

Not right, theres also a black model of the GX-4000D.


I have a GX-4000DB with one channel down (not playing).
Anyone knows what model it is closest to:
GX-4000D, 4000DB, 4000DS or another one?
which schematic or manual would fit it better since I were not able to find the GX-4000DB.
Please, reply here so everyone can benefit and let me know at


The GX 4000D is closest, the

The GX 4000D is closest, the 4000DS or any non-GX models are different from the GX's

AKAI GX4000D/AKAI GX4000DB Service Manual

Service manual uploaded

Manuals download

Thanks so much. So many ppl trying to rip ppl off by overcharging on eBitch...You're the best man :)

Thanks very much for the

Thanks very much for the gx-4000d service manual.. very very much appreciated. I followed it to very closely.. even adjusted the auto shut off lever so that it was at 5mm according to my caliper.. mine was a bit off.. also spent hours on amplifier adjustment.. used an oscilloscope on my computer.. since my sound card has rca in and out.. it sounds way better than when I got it.. in fact.. in comparison to the source channel.. the tape sounds slightly clearer.. only slightly.. you have to have a very good ear to notice the difference.. I also have an akai aa-1150 that I play it through. It's just amazing. I haven't really found much luck in adjusting the bias filters using 100khz though... I've kinda just had to play it by ear until it stopped distorting... it still needs some slight tweaking I believe.. but, overall it's far better than it was.


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