I have a mini-stereo that doesn't have an aux input. As a result, it's just kind of sitting around collecting dust, since I can't use the Empeg with it. Today I got curious about hi-jacking the tape-player, which never got used, even when I didn't have the Empeg. So today I cracked open the case, and went poking about to see what I could see.

What I saw was that the tape player circuitry was attached to the amplifier unit via a nice little plug, labelled with R out, L out, PG, R in, L in, AG, 10V. I dug out one of my four remaining tapes, popped it in the deck, and hit play. Thanks to my trusty yellow multimeter, I discovered that the R out and L out voltages drop to 0 when I hit stop, and rise above 0 as soon as I hit play. The R in and R out never dropped to 0 voltage, so I presume that's the signal from the radio I'd be recording onto the tape if I hit record.

I'm also assuming that R out and L out are 1V signals, since the voltage levels are approximately the same as the voltage levels I measured coming out of the RCA jacks on the back of the Empeg, barring minor fluctuations that I'd expect from having different music playing.

The idea is to hijack those R out and L out wires from the tape deck, and run them to some RCA jacks, which I'll plug the Empeg into. Prestoneato, tape mode becomes AUX in mode.

Sanity check, since I'm still mostly faking it when it comes to electronics: good idea, bad idea?

(In otherwords, I'm not so concerned about wrecking the mini-stereo, but I don't want to do anything with the potential to wreck the Empeg.)

I assume that your voltmeter was set to read a AC signal and not a DC signal right?
If so, then the RCA outputs on the Empeg should be reading about .7 volt in AC mode.

If thats the same level that your tape deck in your mini-stereo outputs, then you're pretty safe to assume that the RCA outputs can connect to the signal INPUTS to your Amplifier in your mini-stereo.
Just keep your RCA wires and empeg well clear of the 10V wire - that could do some damage to your empeg if it got shorted onto the RCA cables by mistake.

The wire labelled AG is the "analogue ground" and is what the RCA cable (between your Amp in your mini stereo and the rear of the mini stereo) "shields" or outer wires in the cable should be wired to - and what one lead on your multimeter should be connected to - the other wire you conenct your multimeter to is the Left or Right "out" signal from the tape deck.
Don't know what the PG wire is for - some kind of Ground signal I'd bet.

The RCA cable to your rear RCA sockets in your mini-stereo will have the two "ground"/shield - (normally bare copper sheath or strands of wire) wires in the RCA cables joined together at the AG wire/connector.

The centre conductor in the each RCA "cable" will connect to the Left or right "input" wire to the mini-stereo as appropriate (red wire in RCA cable to right, white wire to left input) - this wire is normally sheathed from the outer shield/straded wire by a coloured sheath and this is the "signal" carrying conductor (the bare wire is the "ground" or return wire - more or less to simplify things).

Red RCA connector colours mean right channel - White RCA connector colours means this is the left/mono channel.

Look on the rear of your empeg, the two RCA outputs have Red or White "coloured rings" inside the RCA connector sockets to show left or right channel.


Other than the above, it sounds reasonable (- as all ideas do - at least until something goes wrong)

For $20 get you one of these....

http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F002%5F001%5F019%5F005&product%5Fid=12%2D1999

...or one of these...

http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F002%5F001%5F021%5F002&product%5Fid=12%2D2052

You may have to play with the empeg volume to make sure you are not clipping.

With both of these you should be able to connect to about any audio system.

PG could be power ground?

- Trevor

For $20 get you one of these

But going to and back from magnetic or FM radio doesn't help sound quality very much...

I've made the hack considered above on an old one-piece Kenwood radio/double cassette/turntable/amp/equalizer unit.

I hacked into the wires from the play-only cassette deck, attached the wires from the cassette deck and from the RCA inputs to a selector switch and from that to the amp/eq part - for the case I'd ever feel the need to duplicate a tape.

I had no problems with noise or signal levels... YMMV though

/Michael

Agreed, you do lose some quality however if the system does not have RCA connections it probably isn't the best anyway.

The thing I like about the adapters is that they will work anywhere. If I started cutting into my friend’s stereo or a rental car they may not like that.

Hot damn, now there's an idea. An empeg boombox! Just tear open an old boombox and mount a sled (one of robricc's, that is) in there, connect the wires, and BOOM, you have an empeg boombox. Even bester would be one with a CD player on the top so you could switch from empeg to CD. Even bestest would be one that could do digital audio extraction from the CD on top and dump the mp3s to the empeg. Even bestest of all would be one with wireless internet connection to get the ID3 tags from allmusic.com... We can dream can't we?

But for real, ever since I saw that computer with the empeg sled mounted in it, I've been alert to other sled mounting options. Mounting it in a boombox might be a neat idea.

If I started cutting into my friend’s stereo or a rental car they may not like that.

Tsk, tsk... have they no faith in you?

But yeah, one might be in a situation where a hardware mod, while possible, isn't an alternative - and for a temporary setup those solutions are great. In cars, cassette decks seems (at least around here) to start getting scarce - specially in new cars - so the FM version might be the most universally appliable.

But I see no obvious reason not to try the hack if he has any confidence at all in his hardware skills.

/Michael

I assume that your voltmeter was set to read a AC signal and not a DC signal right?
If so, then the RCA outputs on the Empeg should be reading about .7 volt in AC mode.

I tested DC first, and didn't get much. Then went to AC, and started getting readings fluctuating between .15 and .3, which is what I got from the Empeg, as well. I'll double check this before I do anything drastic.

That's a great explanation you gave, thanks!

I thought about both of those. I'll eventually get one of the FM things for road-trips taken in not-my-car, but I don't want one for home use. I also thought about the cassette adapter, but decided I wouldn't like the looks of the wires dangling from the front of the deck. I could probably string the wires through to the back, but what the heck... I'm having fun poking around with electronics and learning stuff.

if the system does not have RCA connections it probably isn't the best anyway.

Actually, it's a fairly decent system (for a bookshelf), it's just a little old. I've certainly seen much, much worse systems that *do* have RCA aux in connections, and I've also seen some newer fairly expensive systems that also don't have aux in connections. I got this system before mini-disc players, iPods, and what-have-you were invented, but long after vynal went the way of the dodo, so there was much less need for aux in.