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Discussion Starter #1
I have a converted Am radio with 2 speaker connection and an RCA amp out connection. The instructions are to use the radio for the front speakers and run the rear speakers off an amp. I have a 4 channel Alpine for this. But I also have a radio shack 8 track that I want to go into the speaker level inputs. Can I run the radio to the amp via the RCA and run the 8 track to the inputs at the same time? I wont run the radio and the 8 track at the same time.

Should I run all 4 speakers from the amp?
 

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You can run all 4 thru the amp, you'll just need a pair of RCA Y cables from radio shack. That's how I run mine.
I used the level controls on the amp to set the relative volumes between the front and the back.

What I miss is the front / rear fader. In fact, it's on my list to find one I can stash somewhere I can reach it and run another pair of rca's to the trunk.

My rear speakers can take WAY more power than my fronts. When I'm listening "quiet" I can use more front to balance the sound, but when I lean on it, the fronts distort unless I can drop the level some.

If your front speakers sound good out of the amp, you get to keep your fader.

Then Bi-Amp the other 2 channels and connect a sub to that Alpine!!!
 

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Discussion Starter #3
Thanks Jim, no sub in my plans :) I have the 4x6 plate for the kick panels and 4" rounds for the rear.

I dont really understand the RCA Y cable though. The 8 track has a pair of speaker outputs, the radio has a pair of speaker outputs and a pair of RCA outputs.

If I put the 8 track into the amp and have all 4 speakers hooked up, will the sound come out all 4 speakers? or just the channel pair I have the 8 track hooked up to?
 

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kevin if you need help on it my kid knows how to do it. on the amp you take rcas from stereo and on 8 track you only got wires probally so you need to modify the ends to make them work.
 

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It sounds like your AM radio is a two channel unit that has an added-on pair of RCA's so you would not be able to fade between the speaker level outputs and RCA outputs.

What would be best would be to add an automatic source switcher for under $40. You connect the RCA output of your AM radio as the master and the 8-track as the slave. When the master is on, the slave is turned off (at the input). When the master is turned off, the input from the slave is turned on. It is all done automatically so you don't have to worry about damaging anything by forgetting to turn one off.

You would also need to add a line level converter to your 8-track outputs to convert them to RCA so you could plug them directly into the source switcher. Most line level converters also have a low voltage trigger which turns on a a 12V line when there is a signal on the speaker line. You would need this to turn on your amplifier if you did not want to add a simple switch.

Connect the AM radio and 8-track (with converter and trigger) to the source switcher, connect the source switcher to the amplifier, wire the amp outputs to your front and rear speakers, adjust your outputs, and you're done.

By using the 8-track as the slave, you could leave it on all the time so that the amp would be on. Then whenever you turned on the AM radio, the radio would take over and play through your speakers. Turn both off and the amp turns off.

Here's a couple of links to what you would need:
http://www.logjamelectronics.com/piempss2.html
http://www.logjamelectronics.com/pieeisloct.html


Now, the easy way is if your amplifier has line level inputs available is to connect the RCA out of your AM radio to the low level inputs of the amp and connect your 8-track speaker level outputs to the line level input of the amp. Post up your amplifier brand and model number and I can probably look it up for you.
 

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Discussion Starter #6
Steiner, Interesting! let me clear a couple things up. I was looking closer at the manuals and am starting to understand.

the AM radio actually has a kenwood AM/FM/Ipod radio inside (one of those $300 conversions). The radio (head unit) has a internal amp powering the front speakers and the RCA out for connection to the amp and rear speakers. It has a fader built in as well and a remote turn-on for the amp.

The Amp is an Alpine MRP F200, it does not have a input selector, so all 4 channels are seperate.

The 8 track is an NOS radio shack model from the 70s with only a right and left 4-8 ohm speaker leads.

I read that the connections recommended by the radio guide of internal amp for the fronts and amp for the rear is not the best. The article recomended powering all 4 speakers from the amp. So I can put the rear channels in the RCA in to 3-4 channel and the AM/FM fronts into the line level inputs on the amp in channels 1 & 2. That way I still keep my fader. That leaves the speaker inputs for 3 & 4 open. I could use those for the 8-track, but I would only hear the 8-tracks from the rear.

Does that info help?
 

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Discussion Starter #7
I was thinking about this on the drive to work.

I can drive all 4 speakers from the amp. Head unit drives rear via RCA (3 & 4 ch) and fronts via ch 1 & 2 speaker level input. The 8 track would be hooked up to the PIE line level converter and run to the RCA fronts (1 & 2 ch).

That leaves the rear ch 3 & 4 speakers. Can I attach the 2 sets of 8-track speaker connections to both the PIE line level converter and the speaker level rear ch 3 & 4 input? I wont have a fader, but oh well.

That just leaves the amp remote on. The head unit has the remote on and the PIE line level converter has one too. Can I attach both to the amp? or will the 12v back- feed to the PIE or head unit hurt them?

I could put a SPDT in the mix, I would just have to hit the switch before turning on the head unit or 8-track. I would run the head unit with my IPOD 90% of the time. The 8 track would be mostly for looks, but would be used for "special" events :D

Am I getting closer? :)
 

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Steiner, Interesting! let me clear a couple things up. I was looking closer at the manuals and am starting to understand.

the AM radio actually has a kenwood AM/FM/Ipod radio inside (one of those $300 conversions). The radio (head unit) has a internal amp powering the front speakers and the RCA out for connection to the amp and rear speakers. It has a fader built in as well and a remote turn-on for the amp.

The Amp is an Alpine MRP F200, it does not have a input selector, so all 4 channels are seperate.

The 8 track is an NOS radio shack model from the 70s with only a right and left 4-8 ohm speaker leads.

I read that the connections recommended by the radio guide of internal amp for the fronts and amp for the rear is not the best. The article recomended powering all 4 speakers from the amp. So I can put the rear channels in the RCA in to 3-4 channel and the AM/FM fronts into the line level inputs on the amp in channels 1 & 2. That way I still keep my fader. That leaves the speaker inputs for 3 & 4 open. I could use those for the 8-track, but I would only hear the 8-tracks from the rear.

Does that info help?

In that case, use a 4 channel source switcher:
http://www.logjamelectronics.com/piempss4.html

With the switcher, you would need two line level converters. One for converting your front set of speaker outputs for the radio to RCA, and the other for converting your eight track. Since you would not need a low voltage trigger, you could just by an inexpensive set of line converters without the trigger function.

You would then connect a set of Y connectors to the eight track's line converter to make it four inputs (non-fading). A Y connector is just a female RCA splitting into two male RCA's.

Connect the eight track as master and the radio as slave. Connect the four outputs to the amp and wire the amp to your speakers.

You would want to use the eight track as master then and not use the low voltage trigger for your amp turn on. The radio would stay on all the time as the slave which would keep the amp turned on, and when you turned the eight track on as master it would switch over to your tape without the amp turning off.

You would want to turn on the eight track and set your amp gains for the front and rear sound to suit you. The radio would still have the fade function.
 

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This looks like the ticket! Just sounds like another $100 to do this correctly :( Thanks!!
If you only need $100 to finish something, then you're my hero.
 

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Discussion Starter #11
Ha! The rest of the car is asking for money all the time! :D I still need to make this big amp fit under the dash! No other place to put it on my vert. Then I have to fit all the wires, mount the speakers, upgrade the alt, etc, etc... you know the drill! :)
 

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I pulled up your amplifier and thought of the easiest and cheapest way to do it.

You amp has both a four channel input and a two channel input, both of which will result in a four channel output.

You will only need two line level converters and one SPST normally closed relay. One of the line converters can be a standard one, but the other should be one with a low voltage trigger for a 12V signal.

Connect the radio fronts to one line converter. Run the output of the line converter and the radio's rear RCA to the channel 1-2-3-4 inputs on your amp.

Connect the low voltage trigger line converter to your tape player. Run that to your amp's 1/3, 2/4 inputs. Connect the 12V trigger line to your amp's turn on terminal.

Connect your radio's amp trigger wire to the coil of the SPST relay and also to the amp turn on terminal. Run the 12V power supply connection for you tape deck through the normally closed set of contacts on the relay.

When your radio is on, it will open the 12V supply to your tape player so that it cannot be turned on. The radio will turn on the amplifier and your fader will work.

When the radio is off, the tape can be turned on. The line converter will turn on the amp. It will play through all speakers but will be non-fading.

It would be best to set up the gains on your amp to get the best front/rear mix with the tape and leave them there. You can use the radio's fader to adjust the mix when you're playing it.
 

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Discussion Starter #13
Hmmm, you kinda lost me now.

I pulled up your amplifier

Your amp has both a four channel input and a two channel input, both of which will result in a four channel output.
Can you let me know where you pulled that up? I have the online manual, but it does not state the 2 into 4 outs anywhere.

Connect the radio fronts to one line converter. Run the output of the line converter and the radio's rear RCA to the channel 1-2-3-4 inputs on your amp.
OK, I understand this. All 4 RCA amp inputs would be for the radio.

Connect your radio's amp trigger wire to the coil of the SPST relay and also to the amp turn on terminal. Run the 12V power supply connection for you tape deck through the normally closed set of contacts on the relay.

When your radio is on, it will open the 12V supply to your tape player so that it cannot be turned on. The radio will turn on the amplifier and your fader will work.

When the radio is off, the tape can be turned on. The line converter will turn on the amp. It will play through all speakers but will be non-fading.

It would be best to set up the gains on your amp to get the best front/rear mix with the tape and leave them there. You can use the radio's fader to adjust the mix when you're playing it.
I understand this section too, but I have to look a little closer at the relay specs.

Connect the low voltage trigger line converter to your tape player. Run that to your amp's 1/3, 2/4 inputs. Connect the 12V trigger line to your amp's turn on terminal.
This is where I am having trouble. After the RCA inputs are filled, that leaves the 4 channels of speaker level inputs and the 1/2 3/4 pre-amp outputs for a sub (which I may do later)

11 Pre-Out Jacks (MRP-F200 only)
These jacks provide a Front + Rear summed
output (Non-fading ). This is an ideal output for
driving a separate subwoofer amp. This output is
full-range, and is not affected by the crossover.

I could not find any 1/2 3/4 inputs. :confused:
 

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Discussion Starter #14
Steiner, BTW, this is a really neat way to control this! Thanks! :beers:

Connect your radio's amp trigger wire to the coil of the SPST relay and also to the amp turn on terminal. Run the 12V power supply connection for you tape deck through the normally closed set of contacts on the relay.

When your radio is on, it will open the 12V supply to your tape player so that it cannot be turned on. The radio will turn on the amplifier and your fader will work.

When the radio is off, the tape can be turned on. The line converter will turn on the amp. It will play through all speakers but will be non-fading.
 

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Discussion Starter #15 (Edited)
Mocked up the amp and it fit! Right between the defrost duct, dash brace and glove box. Clears the ashtray and everything! :hurray: I was really worried about that! I have to fab a mounting plate with bracing everywhere, but that should be fun. Now I just have to decide which way the gain adjustment goes.

Towards the left: It will be a bear to adjust with the dash installed, but the inputs are pointing towards the radio and speakers towards the glove box.

Towards the right: easy to adjust the gain, but the radio inputs will have to go to the other side and speaker wires would be pointing towards the radio. I have to think on that.

On the 8 track issue. I can put the connections into the 1 and 2 speaker level inputs to at least. The question is can I connect the 3 and 4 channel inputs to the 1 and 2 in in series? If I pretend the Amp input are speakers, I can run the negative from ch 1 to the positive of ch 3 and the same for ch 2 & 4 and that would put the ohms at 8 for each side. The 8-track is rated at 4-8 ohms (8 watts :)) and then use the balance for side to sie and the gains for front to back.

How does that sound?
 

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Mocked up the amp and it fit! Right between the defrost duct, dash brace and glove box. Clears the ashtray and everything! :hurray: I was really worried about that! I have to fab a mounting plate with bracing everywhere, but that should be fun. Now I just have to decide which way the gain adjustment goes.

Towards the left: It will be a bear to adjust with the dash installed, but the inputs are pointing towards the radio and speakers towards the glove box.

Towards the right: easy to adjust the gain, but the radio inputs will have to go to the other side and speaker wires would be pointing towards the radio. I have to think on that.

On the 8 track issue. I can put the connections into the 1 and 2 speaker level inputs to at least. The question is can I connect the 3 and 4 channel inputs to the 1 and 2 in in series? If I pretend the Amp input are speakers, I can run the negative from ch 1 to the positive of ch 3 and the same for ch 2 & 4 and that would put the ohms at 8 for each side. The 8-track is rated at 4-8 ohms (8 watts :)) and then use the balance for side to sie and the gains for front to back.

How does that sound?

I apologize. I gave you the wrong info on your amp as I just looked at it quickly. The 1/2, 3/4 connections are pre-outs which would be used to take your signals and run to another amp. I thought they were a combined input to allow you to run one set of RCA's which the amp would combine to supply all four outputs. Sorry.

Those preouts are good to have however if you ever want to add a sub. You can get an amplified 6" or 8" tube fairly cheaply to mount in the trunk later down the line and use those preouts for the signal. Then you'd only need to worry about the 12V signal and +/- power connections to the tube. You'd be amazed at how well just a small sub will round out your music.

Whatevery you do, do not connect any of your line levels going to the amp together or you will damage the output circuitry in the stereo. You would also not want to use the tape player balance as a fader as it would sound terrible as you would have left coming out the front and right coming out the rears or vice versa. You would not be adjusting both channels simultaneously as in fading, you would still be adjusting left/right level.

The best thing to do is to go back to my original (well, second original) suggestion of using the 4 channel source switcher with tape player as master and radio as slave. You may be able to find that switcher cheaper and you can use two regular line converters which should only run about ten bucks a piece.
 

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Thanks. Crutchfield has the 4 switcher for $39, but PIE has the line converters cheaper. I will go that route, but still use the relay to handle the amp trigger :) I appreciate the help!
If you connect the tape as master and radio as slave on the switcher, you will not have to do that. With the radio on when you want to listen to either, it will supply the amp turn-on 12V signal. When you turn on the tape, the switcher will ignore the radio's inputs and use the tape's inputs. The radio 12V lead to the amp will stay high.

Also, since you don't need the low voltage trigger line converters, you can get a cheap set of the Scosche brand from Wal-Mart. I'm pretty sure I've got one stashed away somewhere....
 
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