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Looking for original 1970 Radio/Stereo


ddezso

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The 70's radio was monaural, and there were two styles. One had the seek feature on the volume knob and the other did not. Both had 3 AM buttons and 2 FM.

If I recall correctly, the antenna switch was above the tuning knob for both. There was a later model that had a rocker style switch to the right of the tuning knob, but if memory serves, that was for the later year cars. (Someone please correct me if I'm wrong.)

Enrique

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Yep, Enrique. Your'e backwards. The early style Hitachi AM only had auto seek tuning and the antenna switch to the right side of the radio. The later Hitachi AM/FM had the horizontal switch above the tuning knob. I have a picture of the wrong radio for Derek's car, but no good pictures of the correct one. I guess I better stop my restoration work and take some pictures!

When I bought 26th, she had an FM radio and I later updated her to FM / Cassette. Getting into the restoration thing, I paid dearly for an A+ AM radio and felt really foolish. Finding one in working condition that is only going to light up one 6" speaker so that you can listen to static is going to seem pretty dumb, IMO. I see them on eBay from time to time.

post-4148-14150796179126_thumb.jpg

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Does anyone have or know where to get an original 1970 240Z radio/stereo?

It's the big missing piece for my interior work

I have one home but I still miss the rigth knob, but this is the early model, AM only with the power antenna on the side of the switch/vol button.

post-7137-14150796179283_thumb.jpg

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Does anyone have or know where to get an original 1970 240Z radio/stereo?

It's the big missing piece for my interior work

The correct radio you are looking for looks like this one below..

My understanding is only a Hitachi AM Radio (not stereo) came with the 1970Z.

pb0200010jz.th.jpgClick the pic for full size

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Thank you Chris!

(Sorry about the goof, but I'm glad it was caught. I hate finding wrong info.)

By the way, you CAN put two speakers in the rear of the car, and you'll find that ALL of the plastic panels have the "grill" already pre-drilled for "stereo" speakers. (*)

The HARD part is finding a bracket to hold the speaker onto the left hand side of the car (by the antenna). Fortunately, it is a simple matter of looking at the RH side speaker bracket to fabricate a LH side bracket. Then just simply run a pair of wires from one speaker to the other.

Now, someone with experience with speakers please chime in. Should you wire the additional speaker in parallel or in series? I vaguely recall that one way causes higher resistance (increased ohms) and the other reduces it, which can cause speakers to be blown out. We aren't talking mega-watts of power here, but I'd hate to blow an original speaker (even if replacements are readily available and it would be hard to detect the change).

E

P.S.: (*): There is a subtle difference between the early plastic panels and the later panels. If your car has the vents in the hatch, then it should NOT have a "grill" drilled through in the plastic just above the shock towers. Additionally, the dimensions of the "bump" for the evaporation tank are different between new and old. (plastic evap tank vs. metal)

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Yep Enrique you can add a speaker to the other side assuming he has the speaker grill holes. the orginal owner did it to my Z, using a factory speaker mount plate. I have a 71 with the "air" vents on the Sail panel so the speaker "grill" was there for my car, his 70 may or may not have it.

As far as the wiring goes, If you wire it in parallel (meaning: you put both + speaker wires together and both - speaker wires together and connect them to the factory radio wires) . this way will put more of a strain on your old radio than wiring in series.

If you do it in series you would do it like this: connect the + speaker output from the radio to the + on to speaker "A", then you connect the - speaker output from the radio to the - on to speaker "B" and you run a 3rd "jumper" wire from from - side of speaker "A" to the + side of speaker "B" there by completing the circuit.

Thank you Chris!

(Sorry about the goof, but I'm glad it was caught. I hate finding wrong info.)

By the way, you CAN put two speakers in the rear of the car, and you'll find that ALL of the plastic panels have the "grill" already pre-drilled for "stereo" speakers. (*)

The HARD part is finding a bracket to hold the speaker onto the left hand side of the car (by the antenna). Fortunately, it is a simple matter of looking at the RH side speaker bracket to fabricate a LH side bracket. Then just simply run a pair of wires from one speaker to the other.

Now, someone with experience with speakers please chime in. Should you wire the additional speaker in parallel or in series? I vaguely recall that one way causes higher resistance (increased ohms) and the other reduces it, which can cause speakers to be blown out. We aren't talking mega-watts of power here, but I'd hate to blow an original speaker (even if replacements are readily available and it would be hard to detect the change).

E

P.S.: (*): There is a subtle difference between the early plastic panels and the later panels. If your car has the vents in the hatch, then it should NOT have a "grill" drilled through in the plastic just above the shock towers. Additionally, the dimensions of the "bump" for the evaporation tank are different between new and old. (plastic evap tank vs. metal)

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Connecting speakers in series increases resistance. Two eights = 16 ohms.

Connecting speaker in parallel decreases resistance. Two eights = 4 ohms.

Power is inversely related to resistance so the parallel speakers will be louder, but you may blow them too.

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i got lucky since i saved an old twin post pioneer AM/FM casette from one of my old cars. just had to make a face panel from plexiglass. not great but a coat of black paint and it will pass for now.

one other thing i noticed when i added the pass/side speaker is that you have to be careful of the depth of the speaker. use as shallow a speaker as you can get if buying new.

a standard depth (don't have the specs) speaker's magnet will hit against some of the vent hoses preventing or at least making it difficult to replace the side panels. i fabricated a mirror image bracket and was able to fit an old aftermarket speaker barely. it will do for now, but i will be replacing with a shallower set. if using OEM speakers, the magnet size might not be an issue since i believe they are a much smaller diameter and might clear any obstructions.

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Connecting speakers in series increases resistance. Two eights = 16 ohms.

Connecting speaker in parallel decreases resistance. Two eights = 4 ohms.

Power is inversely related to resistance so the parallel speakers will be louder, but you may blow them too.

Understand that the load on the amp (the radio) will be greater doing it in parallel thus creating a greater risk of blowing the radio itself.

If it was me, I wouldnt want to risk frying my 35 year old radio...i mean you will get a little louder sound by doing it parallel, but are you really looking for louder hissy AM radio sound? or are you trying to go back to OEM for the sake of your Z being more orginal?

for me the answer was to put a stereo/w remote control and 2 speakers in back in a removable(2 screws and a plug and its out)

"box" for decent sound, and leave the stock radio in the dash in working order

maintaining the orginal dash look.

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I don't know what's on AM where you live, but the only thing to listen to down here is Rush Lindbau and cha-cha music from Cuba. I don't think I'm going to be doing too much cranking on the tunes. But you know how it is. I'll show up at a car show some day and somebody will say; "that's not original"! There's enough of that forcasted for Her Majesty! The original AM radio units on a 1970 build would have only one speaker on the left side mounted next to the antenna.

While we are talking about it, though. Datsun offered an optional Hitachi 8-track / radio unit. I believe they were standard to the Fairlady ZL model and optional to the S30-S, HS30, and PS30. Remember the thread we were talking about all the options? Then, I got into a conversation the other day about Clarion being the original intention for the radio units - not Hitachi. I don't think, however, that Clarion units made it to production.

CW-

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Since my goal is to have a mostly stock-looking driver, absolute originality isn't crucial. That said, I do want it to look "period" so I will try to find a stock-looking radio of some kind. But I'll be using both speakers in back, probably with a small amp that has an auxiliary input jack for my iPod.

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Thanks for all the input guys. Since I am not going to have a frame off showcar but just want a tight, clean refreshed Z car, would one of the later radios like the one you pictured 26th-Z, fit into the slot on a 1970? It looks to have AM and FM and I assume it is stereo......?

That way I still have the period look rather than a blue neon flux capacitor retratactable removable DVD flat screen stereo.

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Thanks for all the input guys. Since I am not going to have a frame off showcar but just want a tight, clean refreshed Z car, would one of the later radios like the one you pictured 26th-Z, fit into the slot on a 1970? It looks to have AM and FM and I assume it is stereo......?

That way I still have the period look rather than a blue neon flux capacitor retratactable removable DVD flat screen stereo.

ROFL aint that the truth!

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Regarding the speaker wiring (series vs. parallel), the important thing is to have the total speaker load match the rating of the radio power amp output. In addition, the speakers should have a power rating that is the same or higher than the power output of the radio. I'm not sure where to find these tidbits of information, perhaps in the service manual somewhere?

For arguments sake, let's say the radio is designed to operate into a 4 Ohm load. You could hook up one 4 Ohm speaker, two 8 ohm speakers in parallel, or two 2 Ohm speakers in series. All three variations would present the same 4 Ohm load to the radio.

Now let's say the power output of the radio is 20 Watts. If only one speaker is hooked up, it should be rated for 20 Watts or more. If two speakers are hooked up, they should be rated for 10 Watts or more.

When connecting two speakers together in a mono setup, I'd wire them in parallel. That way if one blows, there is still a load on the radio's power amp. Without a load, the power amp section could burn up.

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  • 4 months later...

Found this while going through some paperwork. Hope it helps others:

Hitachi Car Radio Model KM-1520ZC Operating guide.

Will post more later, but for now:

SPECIFICATIONS:

CIRCUIT SYSTEM: All transistor superheterodyne with RM am. system

TUNING RANGE: FM 88 ~ 108MHz; AM 535 ~ 1,605KHz

TRANSISTOR: 13

IC: 1

DIODE: 9

THERMISTOR: 2

POWER SUPPLY: DC 12V negative ground

CURRENT CONSUMPTION: 200mA (with no signal)

AUDIO OUTPUT: 3.5W (THD 10%)

LOUDSPEAKER: 5 1/8" PM 4 ohms

ANTENNA: Power Antenna (RO-74B)

WEIGHT: 2 lbs 14 oz.

This is from the P7630871 Brochure from Hitachi LTD.

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  • 2 years later...

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