I recently purchased a DX-8 DBX unit for my Teac 80-8(some of you may have seen my posts regarding a diy control cable which I was finally successful in making) I finally used the unit two nights ago tracking drums and was simply blown away by how good it sounds! I was VERY cautious about level setting and with all DX-8 channels bypassed I set my input levels so nothing went over 0db VU. I experienced no "pumping" or "breathing" issues. The tracks sound super clean, quiet and warm as can be, however, on track 7(left overhead) playback there was this intermittent HUGE jump in volume from time to time. The volume suddenly jumps up and then returns to normal off and on throughout the recording. It sounds as though you suddenly cranked up the gain knob or threshold on a compressor. With the dbx bypassed you can hear it on the tape so it seems to be an encoding malfunction. I triple checked all connections and swapped out the DX-8 channel 7 card with channel 4 and sure enough the problem moved to channel 4. I bypassed channel 4(hi hat track) and recorded 2 back to back takes of the same song. On playback I now had the problem on channels 7 and 8 throughout the first take but nothing on the second. I just don't understand what would cause such a huge jump in volume. My inputs aren't hot enough to even create that hot a signal. The dbx encoding circuit must be amplifying it. Suggestions? Any help is greatly appreciated! Thanks.
Yeah after messing with this thing some more I'm pretty sure the relays are the problem. I cleaned the card slots thoroughly and the 3 problem channels are still intermittent when I wiggle or tap on the cards. It sounds as though the DBX is engaging and disengaging, thus it seems like a big jump in volume but really its the same as if the decode was turned off. I tried cleaning them but all I can do is spray them you can't really get to the contacts to burnish them. I ordered 2 new replacement relays to try so we'll see if that works. Unfortunately relays are about $12 bucks a piece plus shipping. I found some on ebay for $8 and $5 shipping but supply is limited and if more go out, which they eventually will, this is gonna get expensive. I'm gonna be using this thing on a daily basis and I LOVE the sound so in the long run its worth it.
Since heat is the known enemy, I'd suggest keeping the dx8 separate from the 80-8 and either removing the top plate or modifying it with a few vent holes if none exist.
Since heat is the known enemy, I'd suggest keeping the dx8 separate from the 80-8 and either removing the top plate or modifying it with a few vent holes if none exist.
The unit is under the 80-8 and there is plenty of ventilation. The DX-8 is vented top and bottom and there is about an inch of space above and below. The relays themselves on these 3 problem channels seem looser than the others when you shake the cards. I think they're just worn out.
I just received the 2 new relays I ordered and installed them in the channel 8 card and it now seems to be working perfectly and is not intermittent when I tap or wiggle that card. I just ordered 4 more for the other 2 problem channels. The rest of the channels are solid, at least for the time being. Here are some pics of the installation:
thanks! i won't be freaking out if i need to work on it now........lol the "tech" who last worked on this deck said two channels were messing up as described and thought it was head alignment which made no sense to me..............
