Stumped: Beat-up Akai deck doesn't like NR?

[lo.fi.love]

Hey folks,

I've got a really interesting problem here. My tape echo deck, an Akai 1730D-SS, is acting up and it will no longer "accept" a dbx encoded signal on one of its channels.

I've had it hooked up to a dbx 150x NR unit for nearly a year and it worked just fine until last week, when it stopped receiving a signal on one of its channels. I tried a few things to find the cause. Here's what I did:

1. dbx 150x, with the same configuration as always (record volume knob in the same position, pots on the 150x in the same position, cables checked out, etc). No signal / faint signal.

2. I disconnected the NR and made a straight connection from a cassette deck to the Akai. The channel responds as expected when monitoring the tape AND the source. Strong signal. Sounds good when I plug in my headphones. No distortion other than a faint mains hum.

3. I tried different cables, using the dbx 150x again. No signal / faint signal when monitoring the source or tape.

4. I tried using a dbx type II NR unit, different cables. No signal / faint signal when monitoring the source or tape.

This is an old, beat up tape deck. It has four channels but I only use the "Left" channels ("front" and "back") because there's a weird mechanical noise on its two "Right" channels. It also wasn't taken care of by its previous owner. The Left "rear" VU flutters a bunch when I turn on the power.

Has anybody seen this happen? What could possibly cause this problem? I'm inclined to think that it's just an old deck that has lived past its usable life.

Opinions? Guesses?

 

[vincedog3]

wow that is a good one. I would think a bad capacitor in the buffer circuit if the Akai employs such a scheme. That is weird indeed.

 

[lo.fi.love]

I think I'm just going to chuck this deck into the trash.

(I live on the West Coast, so this actually means "I'll take it to the electronics recycling facility" )

A co-worker is going to sell me a TEAC X-10 deck and a X-10R that her dad gave her (I'll calibrate & clean both and sell one of them), so I'll use one of those as my new effects deck. Plus, I can use it to play all of the funky 3.75ips tapes that I've accumulated. The Akai was usable only as an effects deck because of its weird issues.

 

[Tim Gillett]

If the Akai records and plays back a normal input then there's nothing wrong with it. If it doesnt work with the dbx there's something wrong with the dbx.

A recorder that will work normally but "doesnt like NR"? No such animal AFAIK.

Cheers Tim

 

[lo.fi.love]

If the Akai records and plays back a normal input then there's nothing wrong with it. If it doesnt work with the dbx there's something wrong with the dbx.

A recorder that will work normally but "doesnt like NR"? No such animal AFAIK.

Cheers Tim

Yeah, that's why this is so confusing. I tried literally every option that I could but for some reason it still wouldn't work. I'm going to do some more trouble shooting but I'm still going to dispose of this deck once I get my hands on one of the TEAC decks.

 

[Richard King]

If I recall correctly, the DBX 150x is a 2 channel unit. It sounds to me that one channel is working and the other isn't. I would simply swap the inputs/outputs on the two channels and see if the problem goes to the other channel on the tape deck. If it does then you know for certain that the problem is in the DBX unit (or, less likely, the cables). From your description I would suspect the DBX unit(s) before the deck.

 

[Richard King]

I'm still going to dispose of this deck once I get my hands on one of the TEAC decks.

I don't blame you. Those Teac decks were quite nice in their day.

 

[technoplayer]

I'd put my money on the Akai having a funky issue. I have owned or used several different models since the 70's, and to a number each one flaked out on me at one time or another. My first 1730D-SS had the cheap metal cam thats a key part of the play lever mechanism just disintegrate.
The next one had intermittant electronics. IIRC it would start playing fine then one or two channels would just slowly fade out...not CUT out mind you, but fade out as if a know were being turned.

It's gotten so I am a die-hard for the TEAC/ TASCAM machines. Entirely different world with build quality.

 

[jedblue]

Just as an aside Jeff, and something you're probably already aware of with your 5050, but for all my 1/4" two track and full track machines I find I have no need for noise reduction at all, either in tracking, master or echo duties.

If you could score another cheap 1/4" two track for echo duties rather than a 4 tracker, you could probably ditch the dbx completely?

Geoff

 

[lo.fi.love]

If you could score another cheap 1/4" two track for echo duties rather than a 4 tracker, you could probably ditch the dbx completely?

Perhaps, but I'm a big fan of echo at 3.75 and 7.5 ips. The hiss @ 3.75 could be more than I'm willing to deal with. I'm sold on the TEAC X-10R that I mentioned, so I'll try it without NR once I get it.

I actually haven't been able to use the MX-5050 yet. It still needs to be calibrated. My friend with the oscilloscope and MRL tape needs to get off his lazy butt... !

 

[jedblue]

I use the Nagra at 7 1/2 for echo and that's not a problem noise wise, nice and clean. I'll set it up at 3 3/4 as well and see if that's too noisy and let you know. I don't bother with them at 15 ips for echo. I find that it's just too short.

You might find with the 5050 that you can get it pretty close with it's own internal oscillators and the adjustment pots although it'd be good to calibrate the playback levels off a tape first. I got one out of Germany for a tenth of the price of an MRL one and I'm just about to pick up a millivolt meter off eBay so I'll be all set to calibrate all my decks on my own. I'll send you the link for the reference tape if you like.

I've also got some links somewhere for 5050 manuals that you can download that describe how to calibrate it off the internal oscillators if you don't have them.

G