dbx 150 without manual

[moviebuff2]

Hi everyone:

I just got a dbx 150 without its own manual. The equipment is for my project of dubbing some of my own audio reel-to-reel tapes onto my video. The tapes were recorded with dbx type I noise reduction equipped with my Teac X2000R. Unfortunately, my TEAC has been on strike for some time. My working Sony reel-to-reel does not have dbx noise reduction.

I want to use the dbx 150 to decode the audio signals from the Sony before feeding them to my soundcard.

I don't have problem making the connections between the equipments. What I don't know how to use is the Noise Reduction (In & Out) on the front panel of the dbx 150. What do I have to use in my case (see below simplified diagram)? In or Out?


Sony reel-to-reel (playing dbx-encoded audio signal without dbx encoder/decoder-------->dbx 150--------> Computer sound card

(Cornucopia, I need your expertise )


Thanks

[Bodyslide]

Manual can be found here, but not sure what the cost is.

http://www.vintageaudiomanuals.com/-D-.htm

[moviebuff2]

Thanks, Bodyslide

I think this is the same person I found on eBay after I had posted my inquiry here. The name of the store is also Vintage Audio Manual. I got one copy.

Cheers

[BJ_M]

hmm - i just sold one on ebay, i may have the manual for it somewhere ..... ill look around


i have 2 more plus a lot more tube and vintage gear when i rebuilt my studio last year

[moviebuff2]

Thanks BJ_M

I think I figured out what the manufacturer meant by "In" and "Out". "In" means "On and "Out" means "Off"!

I thought the company referred to Line In and Line Out.

Anyway, I will refer to the manual when I receive it in order to make sure that I set up everything correctly.

[moviebuff2]

Hi everyone:

I have been struggling with this dbx 150 and need your help, please.

I have some dbx I-encoded tapes. I want to play them with my tape player that does not have a dbx decoder. So I bought this used dbx 150 to decode the signals coming out from my tape player.

I connected my tape player's Line Out to the dbx 150's From Machine Output. Then I connected the dbx 150's To Console Input to my receiver's Line In. Then I pressed the In button of the Noise Reduction of the dbx 150.

I think the dbx-encoded sound from the tape player is decoded by the dbx 150. The decoded sound is then sent to the receiver.

But the sound is terrible. Too much bass. Both bass/treble settings are at middle, i.e. no gain, no reduction. It sounded just like I was decoding a non dbx-encoded tape. And I am 100% sure that the tape was encoded with dbx I because I encoded it with my TEAC R2000X.

Please help!

[SingSing]

From the ebay photos, there are two pairs of input/output. One pairs of the input/output is from pre-amp in -> compress -> output to recorder, the other should be recorder out -> expand -> to power amp.

You may be using the wrong pair of i/o.

Note : I remebered the dbx/dolby format war, where the more political savvy won.

[moviebuff2]

Hi SingSing:

Thanks. Yes, there are 2 pairs of input/output. One is label Tape Machine, the other, Console. I think dbx uses Console to refer to Receiver (Amplifier).

I think my connection is correct since when I switched the Noise Reduction to Out (i.e., Off), the sound was "perfect" with all hisses & noises since it was not decoded.

A friend of mine just told me that many sound cards cannot handle the dbx input and this causes distortion like "excessive bass".

I tried with my A/V receiver. The same thing happened.

My friend told me to read carefully the manual to see if the manufacturer mentions anything about "input overload". Sure enough, silly me who assumed a Panasonic to be the same as my David Hafler! LOL

My Panasonic has something called A/D Attenuator. This function is set to "off" by the manufacturer. When a sound input is too much for the receiver to handle, setting the A/D Attenuator to "on" will handle it. I changed the setting to "on" and everything sounds fine now.

This never happened when I still had the David Hafler. dbx sound coming from my TEAC R2000X was handled by them without any troubles.

Now I know why my David Hafler power amp & preamp sold within minutes after I put them on eBay! hm... And I thought that I dealt myself a good deal by changing them for a Panasonic with "video" stuff. gr...gr...

Cheers

[BJ_M]

you sure it is not dbx type 2 ?

another thing is that the dbx 150 will have +4dBu levels on the output and your consumer equipment is -10dBV ... The standard -10dBV level equates to 316mVRMS which is about a quarter of the voltage of the professional +4dBu reference level, or almost 12dB lower. You would be overdriving your receiver. You can pad down the output or get a converter.

[SingSing]

It does sounded like overload. The blue tuning ports at the front panel does look like output level controls, Try those. Or Buy those $48 audio attenduattor.

[moviebuff2]

Hi BJ_M & SingSing:

Yes, it's dbx Type I. My tapes were recorded with the TEAC R2000X which is equipped with dbx Type I only.

When I turned off the A/D Attenuator of my receiver, the signal "over" was lit frequently and I heard distortion. The manual says this is "input overload" and when this happens, turn on the A/D Attenuator. I did that and the problem goes away.

Do you think this input overload can cause any damages to my receiver?

Thanks

[SingSing]

Ney, audio signals are self limited when designed by electronics engieers. The distortion you heard are known as clipping, were the excess signals are leveled off by circuit.