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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 11th Jan 2019, 10:06 pm   #1
barrywebb
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Default Akai GX4000D poor sound

Hi all i have just bought this deck and the sound from phones socket is very poor, distorted, etc.
Not tried it with a output amp at the moment just wondered if anyone has had this issue.
Barry.
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Old 12th Jan 2019, 6:14 am   #2
TIMTAPE
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Default Re: Akai GX4000D poor sound

This could be various issues.

Headphones need to be compatible with the deck. The deck is designed nominally for 8 ohm headphones. If yours are higher than that, the headphone volume will probably be lower, perhaps much lower. Turning the deck's output to maximum may well cause distortion.

Before anything else, I'd suggest connecting the deck to a stereo amp's line in sockets via the deck's line outs.
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Old 12th Jan 2019, 11:43 am   #3
Kentode
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Default Re: Akai GX4000D poor sound

Hi Barry, are you using a known good tape and recently cleaned guide paths and heads?

Or is it an unknown tape that came with the deck?

You may also need to demag the heads.
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Old 12th Jan 2019, 9:43 pm   #4
barrywebb
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Default Re: Akai GX4000D poor sound

Hi its a known good tape recorded from my Akai 4000DS mk2 stripped it down today and cleaned all controls with contact cleaner.
Plugged it in a amp with good cables but its still the same sound very distorted seems to be the head switch when i spray it it wont work for 20 mins and then comes back to life but mainly on the right channel and after flicking the switch about 5+ times it comes on left channel as well as right.
But still very distorted i think i may have been standing for many years.
Any more help would be much appreciated.
I have also cleaned the heads with 99.9% Alc.
Barry.
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Old 13th Jan 2019, 1:01 am   #5
Michael Maurice
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Default Re: Akai GX4000D poor sound

If it is the track selector switch, you may have to remove it completely and strip it right down to clean each contact individually or even replace it if you can get one small enough.
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Old 13th Jan 2019, 2:36 am   #6
TIMTAPE
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Default Re: Akai GX4000D poor sound

The only switch which can cause complete loss of signal is the Monitor switch. The others like Tape type, EQ arent nearly as critical for this.
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Old 14th Jan 2019, 12:30 am   #7
barrywebb
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Default Re: Akai GX4000D poor sound

Hi I have cleaned the monitor switch and it seems to be working fine the only problem seems to lie with the head selector switch I have managed to get hold of one on ebay s/hand but it has to come from across the pond USA.
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Old 14th Jan 2019, 12:37 am   #8
stacman
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Default Re: Akai GX4000D poor sound

Isn’t the Akai 4000 models the ones with the transistors that go faulty?, 2SC types, Ive got a GX 4000 that plays back ok but recordings are distorted, more on one channel than the other, probably a similar issue, Will have to get someone to look at it ,
Regards, Alan.
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Old 25th Jan 2019, 11:40 am   #9
barrywebb
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Default Re: Akai GX4000D poor sound

Would anyone know what and were the bad transistors are on the main board there are quiet a few on there and i would rather not change them for the sake of it if most are good.
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Old 25th Jan 2019, 2:38 pm   #10
barrywebb
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Default Re: Akai GX4000D poor sound

The more i look into it the more Transistors sc458 with black legs i find.
Is that what i should be looking for?
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Old 25th Jan 2019, 3:35 pm   #11
stacman
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Default Re: Akai GX4000D poor sound

Yes very common on these models, the transistors go noisy, pretty sure there has been threads on this issue in the past recommending compatible replacements, and how to change them.
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Old 25th Jan 2019, 3:46 pm   #12
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Default Re: Akai GX4000D poor sound

Yes, for a common problem with those types of transistors see Post 16 in this thread:

https://www.vintage-radio.net/forum/...d.php?t=115284

Lawrence.
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Old 25th Jan 2019, 9:05 pm   #13
TIMTAPE
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Default Re: Akai GX4000D poor sound

Quote:
Originally Posted by barrywebb View Post
The more i look into it the more Transistors sc458 with black legs i find.
Is that what i should be looking for?
Yes from memory they are the faulty ones. I think there can be about 16 of that type involved and I'd replace them all on sight. For years I used to replace them wholesale on Akai tape machines with common BC types but the pinouts are different and it's easier to make a mistake when bending leads to go into the correct board holes. I eventually went for new stock 2SC 458's from my normal trade supplier. With the PCB in situ, replacing them can be difficult. Patience is much needed !
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Old 28th Jan 2019, 6:44 pm   #14
barrywebb
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Default Re: Akai GX4000D poor sound

Well got there in the end and it sounds lovely.
I replaced all of the 2SC 458 Transistors there was 14 in total all had black legs.
All back together and in pride of place with the rest of my vintage gear.
Just so you all know you can change the transistors with out removing the board but you have to remove the board holding screws so you can pull it out just enough to get your hand in to remove them.
Anyway all done and thanks for everyone help with this project.
Barry
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Old 28th Jan 2019, 7:33 pm   #15
stacman
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Default Re: Akai GX4000D poor sound

That’s handy to know Barry, as I stated, I have a GX4000, what Transistors did you replace them with, and I might be able do it myself without a major stripdown,
Regards, Alan
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Old 28th Jan 2019, 10:06 pm   #16
barrywebb
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Default Re: Akai GX4000D poor sound

Alan ive sent you a PM.
Barry
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