preamp issue

[aje123]

I just picked up a cheap used preamplifier for my kenwood tuner and km-893 amp.My problem is the pre is Aiwa with the round 8 pin connector on the tuner in and on the output to amp,my amp only has rca inputs?? I do believe i can run tuner to rca pre aux and use it that way but have no way to hook up amp.I have never saw a preamp with these type of conn. before,Any way to make it work with cables or adapters ?? its just temp. for testing uses. thanks a bunch

 

[Blue Shadow]

not much we can do without a model number.

If you can find the manual that tells you what pins have the signal you need you can make a connector or go in and mod the unit.

 

[Ds2000]

Or a pic of the back.

 

[aje123]

Here is a pic.

 

[Ds2000]

Yeah no work around. May need to make a din to rca cable. or see how it is connected inside and fudge an RCA connection from it.

 

[gtv2000]

If those are 5 pin DINs a standard DIN Tape to RCA adapter might work. You can search eBay for them.

 

[aje123]

not 5 pin or does it just use 5 pin f the 8

 

[Blue Shadow]

The SM for the GX-110 is on HFE and it shows how that unit is hooked up to the DIN plugs. Most are 5 pin but there is an 8-pin. If the connections are standard for the 5 and 8 pin units meaning a 5 pin will plug into an 8 pin you could use these 5-pin to RCA which are available on the web, verifying that the connections are what you need...pin whatever to tuner L, tuner R and some you don't need and the ground.

I would think that Aiwa did this unit the same as the GX-110 and you might search that unit as I believe we have gone through this unit once for this same reason here on AK.

If this is going to be YOUR unit, I would rip out that damn DINs and slap in a nice piece of plexiglass with some RCAs mounted in it for those connections, losing the interconnect to the player for auto play features, I guess.

 

[aje123]

thanks all, for the info. i will look into finding some adapter cables,i have seen 5 pins.

 

[loudnoises]

thanks all, for the info. i will look into finding some adapter cables,i have seen 5 pins.

Those look like 8pin jacks. Just count the holes, the sizing of the connector is standard. Search that site for "8 pin din" and you'll find cables. I fully recommend checking schematics before connecting a cable tho, not all cables are wired the same, and there's no way of knowing if Akai did a 1:1, 2:2 etc or if they went 1:8, 2:7 etc. It's like ethernet cables. there's the standard 1:1, then there's also crossover cables with conductors swapped. Don't get mini-din, wont fit; Large din. Check schematics, if it's a normal pinout cables are cheap, if not plugs are also cheap.

5 pin is MIDI. Don't buy that.

8 pin was used in car audio (adcom, alpine et all) in the 80s +90s, but aside from that there's likely nothing current that uses it anymore. But cords, jacks and plugs are all readily available. Most car companies switched to min-din later on as well. The large din connectors work great, but they're very easy to crush vs the mini-din.

Looks like it might have a balanced output. Might be very nice in the future for you paving an easier upgrade path.

 

[rlisin]

Not a balanced output.

You need an 8 pin DIN plug. Buy one and make your own cable (or have it made for you).

If you buy an RCA to 8-pin DIN cable (if you even find one, which I doubt), it will most likely have a different pinout. That will be bad, best case the cable will not work, worst case you'll damage your amp and speakers.

According to the service manual, this is the way the plug should be wired:

Plug is male (left).
Pin 2 is ground (-) for both channels.
Pin 3 is L+.
Pin 5 is R+.

That's all you need to and should connect.

The other active pins in this preamp's output are 1 (power control output), 6 (spectrum analyzer output) and 7 (described as "H input in AFB on" - whatever the hell that is). You DO NOT want to connect any of these pins to your power amp, especially pin 1.
Pins 4 and 8 are inactive.

DIN plugs are confusing because they are symmetrical and it's sometimes hard to tell which side is which. If you're not sure which side is which when looking at the plug (for example whether the pin you're looking at is pin 4 or pin 5), connect the right channel first (pins 2 and 5). Ground is pin 2 which is in the middle, so it can't be confused with another pin. R+ is pin 5. If you get the side right you'll get the preamp output signal. If you get the side wrong, you will connect to the inactive pin 4 and get nothing. But because pin 4 is inactive, you will not damage anything.

It is important to get it right before connecting the left channel. If you confuse pin 3 (L+) with pin 1 (power control output) you will send 20V to your power amp input (if i'm reading the schematics right). That will be very bad.


Service manual from which I got this information is here:

https://freeservicemanuals.info/en/servicemanuals/viewmanual/Aiwa/GX120/BX120/

 

[aje123]

thanks all i just have some issues to work out, will make it work soon. thank you

 

[aje123]

hey all, i just ordered some 8 pin din's along with a few caps from Mouser will get tomorrow. I hope i have some time this coming weekend to play around with this issue. I will keep you all posted. thank you

 

[aje123]

i just started this making cable issue,I had made a cable last night,for preamp to amp.I could only get schematic for gx-110 but should be same ? My need to knows are:Is the left right channels same pins from tuner into pre as preout to amp. HFE gx-110 shows left/right neg. for some odd reason?? thank you

 

[aje123]

update made one cable,from output of preamp to amp.I then ran tuner through aux. input on preamp.I turned it all on get music through both speakers but have a humming noise in speakers with the music which gets louder with volume?? what next?? any ideas thank you

 

[loudnoises]

update made one cable,from output of preamp to amp.I then ran tuner through aux. input on preamp.I turned it all on get music through both speakers but have a humming noise in speakers with the music which gets louder with volume?? what next?? any ideas thank you

recheck your connections inside the cables, might have a strand shorting where you soldered.

 

[aje123]

will do, but i rechecked it all,yes possible. any pther options if all good? thanks

 

[loudnoises]

will do, but i rechecked it all,yes possible. any pther options if all good? thanks

nothing having to do with the cable, if it's indeed wired right. Never seen inside one of those.

 

[aje123]

checked all. I even thought it was the amp,but tried my sansui as an amp on aux. which I know is good and still humming but have music. ground pin 2, left+ 3, right+ 5 thats it. thank you
.

 

[aje123]

made the ground connections for both channels in cable where it goes to the rca plugs,twisted outer strands together an soldered to a wire leading to pin #2 ground of the 8 pin din. Should i have not done this at this mid point location?? It seems its a loud hum or feedback hum??