DBX-400 and good IC's to do the job right

[jbeckva]

All wires are not created equal Jer...

Yep or PCB layouts... Interesting.

 

[premiumplus]

Here's a PDF file of the original OM. I just got one of these too, and I was surprised at the complexity of the unit when I opened it up. I don't think you can have out of phase signals with it, because I checked out all the connections with a low ohmmeter, looking for a dirty switch or other fault before I hooked it up. All the outer shields of the RCA connectors are to ground, which I believe would preclude the possibility of out of phase operation, right? It's totally passive with the exception of the LED indicators.
I'll be interested to see what you discover. I was going to clean all the switches on mine but they are all working great, and that's a very good thing. It looks like a PIA to disassemble to the point of getting de-oxit into those switches.
FWIW, I can't hear any signal degradation with or without my 400. It sure solved a lot of interconnect issues for me!
View attachment dbx 400 Owners Manual_original.pdf

 

[jbeckva]

Here's a PDF file of the original OM. I just got one of these too, and I was surprised at the complexity of the unit when I opened it up. I don't think you can have out of phase signals with it, because I checked out all the connections with a low ohmmeter, looking for a dirty switch or other fault before I hooked it up. All the outer shields of the RCA connectors are to ground, which I believe would preclude the possibility of out of phase operation, right? It's totally passive with the exception of the LED indicators.
I'll be interested to see what you discover. I was going to clean all the switches on mine but they are all working great, and that's a very good thing. It looks like a PIA to disassemble to the point of getting de-oxit into those switches.
FWIW, I can't hear any signal degradation with or without my 400. It sure solved a lot of interconnect issues for me!
View attachment 15048

I can hear one tho.. and that is the weirdest thing. The switches all operate perfectly. Hmmm... I think I am going to try starting simple (line in to line out, all monitors and proc loops switched out, and up/down through the tape loop on the preamp), then see where it goes wrong. Knowing my luck tho, I'll get it all patched back in, and then not have any issues anyway...

 

[BubbaH]

Im pretty sure I have read other threads elsewhere, of people having similar issues when hooking it up direct like that. At least sound degrade. I bought mine used. Have always just run it through the tape loop as you described. Much like premium, it has always worked perfectly for me. I dont use any processors, and use the processor side for more inputs.

 

[jbeckva]

Well I got it hooked back up. Signal path for testing is - CD in, up to the 400 via the pre's tape 1 loop/monitor, back down with nothing patched in, and out to the amp via the pre's output stage.

Sounds good...

Maybe I don't push my luck at this point... or I might tho LOL. Ideally I'd like to have the digital side with the same capabilities as the analog side i.e. being able to copy both ways, and both being able to record the phono output.
...
...
...
However... and going along with Joe's point ... (I've completed the above - digital on one loop, analog on the other, no EQ)

Bet this was my main "bottleneck".. piece of crap IC I didn't realize I put back into play. The gold plated kind I have now do a much better job, and I'm now accustomed to them.

Guess I am a believer now, hehehe. Now who's got a few tara labs hanging around, collecting dust???



("Professional Grade" - my ass... )

 

[jbeckva]

ps.. moving this out of the DIY section. Solder iron "threat" cancelled..

 

[premiumplus]

I've had strange problems with interconnects before. Is it possible that you have an open ground connection on one channel of that IC? A ground loop condition might have happened and played hell with your frequency response. I've had strange things, real strange things happen with flakey grounds. On the subject of interconnects, my humble opinion is that the main improvement we get from a new set of cables (at damn near any price too) is a new, good (at least for the moment!) set of connectors and a nice electrical connection at the RCA connectors. I have seen it so often in my experience with RCA cables! I remember working in stereo sales back in the seventies and having systems set up all over the store, each with a handful of cables, and loose grounds would cause grief. Sometimes they'd hum, but many times the sound would suffer just like you describe in your original post.
You've got a sweet system, Jer! Don't get bummed about the dbx 400...It solved a bunch of problems for me (2 tape decks, 3 processors, an equalizer, a line in from my secondary system, and an input from my PC) and I can hear no degradation of signal quality. The 400 is a nicely engineered unit and it uses high quality switches.

 

[Gepetto]

Well I got it hooked back up. Signal path for testing is - CD in, up to the 400 via the pre's tape 1 loop/monitor, back down with nothing patched in, and out to the amp via the pre's output stage.

Sounds good...

Maybe I don't push my luck at this point... or I might tho LOL. Ideally I'd like to have the digital side with the same capabilities as the analog side i.e. being able to copy both ways, and both being able to record the phono output.
...
...
...
However... and going along with Joe's point ... (I've completed the above - digital on one loop, analog on the other, no EQ)

Bet this was my main "bottleneck".. piece of crap IC I didn't realize I put back into play. The gold plated kind I have now do a much better job, and I'm now accustomed to them.

Guess I am a believer now, hehehe. Now who's got a few tara labs hanging around, collecting dust???

View attachment 15051

("Professional Grade" - my ass... )

Professional grade is a great marketing term...you have to be very careful who is using the term

 

[eminence1963]

I've had strange problems with interconnects before. Is it possible that you have an open ground connection on one channel of that IC? A ground loop condition might have happened and played hell with your frequency response. I've had strange things, real strange things happen with flakey grounds. On the subject of interconnects, my humble opinion is that the main improvement we get from a new set of cables (at damn near any price too) is a new, good (at least for the moment!) set of connectors and a nice electrical connection at the RCA connectors. I have seen it so often in my experience with RCA cables! I remember working in stereo sales back in the seventies and having systems set up all over the store, each with a handful of cables, and loose grounds would cause grief. Sometimes they'd hum, but many times the sound would suffer just like you describe in your original post.
You've got a sweet system, Jer! Don't get bummed about the dbx 400...It solved a bunch of problems for me (2 tape decks, 3 processors, an equalizer, a line in from my secondary system, and an input from my PC) and I can hear no degradation of signal quality. The 400 is a nicely engineered unit and it uses high quality switches.
View attachment 15055

Is that a sub on the floor?
What kind is it, if it is?

 

[jbeckva]

I've had strange problems with interconnects before. Is it possible that you have an open ground connection on one channel of that IC? A ground loop condition might have happened and played hell with your frequency response. I've had strange things, real strange things happen with flakey grounds. On the subject of interconnects, my humble opinion is that the main improvement we get from a new set of cables (at damn near any price too) is a new, good (at least for the moment!) set of connectors and a nice electrical connection at the RCA connectors. I have seen it so often in my experience with RCA cables! I remember working in stereo sales back in the seventies and having systems set up all over the store, each with a handful of cables, and loose grounds would cause grief. Sometimes they'd hum, but many times the sound would suffer just like you describe in your original post.
You've got a sweet system, Jer! Don't get bummed about the dbx 400...It solved a bunch of problems for me (2 tape decks, 3 processors, an equalizer, a line in from my secondary system, and an input from my PC) and I can hear no degradation of signal quality. The 400 is a nicely engineered unit and it uses high quality switches.
View attachment 15055

No fears - it's sounding good now. I think those old IC's I had were junk, really. Whole lot of insulation to fool one into thinking there's good conductivity, but in reality...

 

[jbeckva]

Here's what I'm currently using. Although they've been known to do some rca jack mangling if you're not careful, overall decent quality. Until/if I ever go with trying a pair of the big-dog kind, which I'll be hooked and then...

 

[BubbaH]

Those look decent from the pic. Cant be any worse than the Mono Price IC's. The first install was extremely hard to connect. Seems though, after being connected for a while they are no longer as tight a fit as they were when new.

 

[Web Police]

You have a screwdriver pinching the cable, that can't be any good for it. If pinched hard enough it could alter the phase angle by 180 degrees.

 

[jbeckva]

You have a screwdriver pinching the cable, that can't be any good for it. If pinched hard enough it could alter the phase angle by 180 degrees.

That was to hold it in the right position, so everyone could see the tiny ass signal wire with the shield not that much bigger. POS cables.

 

[Gepetto]

No fears - it's sounding good now. I think those old IC's I had were junk, really. Whole lot of insulation to fool one into thinking there's good conductivity, but in reality...

View attachment 15056

Do you see a shield Jer??

 

[jbeckva]

Im sure if I put it under a scope. But yup I could build an ic out of cheap earbud cables that would be better

 

[orange]

You know, Jer, that if you put the L on R or manage to run input on the output side etc you can have all sorts of fun.

 

[premiumplus]

Is that a sub on the floor?
What kind is it, if it is?

The black box in front of the grandfather clock? It's a 12" guitar extension speaker cab I built. Semi open back, with a 12" Celestion greenback speaker in it.

 

[premiumplus]

Here's what I'm currently using. Although they've been known to do some rca jack mangling if you're not careful, overall decent quality. Until/if I ever go with trying a pair of the big-dog kind, which I'll be hooked and then...

View attachment 15057

Those look identical to the ones I'm using. Are they single cables, not stereo pairs? 6 foot long, fairly stiff wire? I bought a bunch of them. They do grab those RCA jacks like you said!
I'll post up some pix tomorrow...

 

[Web Police]

Do you see a shield Jer??

Some of them Skanky Chaska whores would cut the blade off the screw driver and call the handle a Dalkon Shield.