Pacific Recorders Multilimiter

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Baltimore

Well-known member
Joined
Nov 19, 2005
Messages
268
Location
Baltimore, MD - the Charm City
anyone have any info on these boxes? I'm looking to disable the "feature" where the output signal (seemingly randomly) flips polarity...here is why:
I was tracking bass for this motorhead-ish band and per the bassist's request didn't use a bass amp. I split the signal to API>multilimiter>tape and rat pedal>API>tape, recorded on two separate tracks. I only listened to the distorted channel during tracking (bassist was in control room, he only wanted the dirty). come mix time I realize that the multilimiter changes polarity a few times each song. I cut the wave form and flipped the flopped parts and was able to work around it, but what a pain in the ass.

I usually HATE DI only bass, but these tracks sound pretty amazing and I'd like to use this setup again, without the hassle.
 
[quote author="Baltimore"]anyone have any info on these boxes? I'm looking to disable the "feature" where the output signal (seemingly randomly) flips polarity...here is why:....

....I usually HATE DI only bass, but these tracks sound pretty amazing and I'd like to use this setup again, without the hassle.[/quote]

I just unpacked a bunch of manuals and stuff after a recent move, and I think I saw one for the Multilimiter. If so, I'll check it and get back to you.
 
Found the manual. This box is made in a motherboard-daughte board configuration. One of the daughterboards is the AM process card. Find it, it should be labeled.

On this card is a trimpot, labeled R321. Turn this pot fully counter clockwise, and cycle the front panel TEST/OPERATE switch to the TEST position and back to OPERATE. This will remove the phase flipper and set it to positive phase.

This unti also contains a PEAK CLIPPER circuit. To minimize its' effects, find trimpot R309 and turn it fully counter clockwise. On the front panel, find the POSITIVE THRESHOLD control, and turn it fully counter clockwise. If you want to remove the PEAK CLIPPER (diode clipper) completely, you'll need to remove LEDs D305 and D306. I'd also replace IC305 with something better than the 1458 that's in there.

On another note, there is a pretty steep high pass filter on the input that has a rool-off of 54db per octave, with a cutoff of 40Hz. Removing this would be beyond the scope of this post.
 
Hiya JD,

would there be any chance at all, of getting a copy of the manual from you ? ( Scan / Photocopy etc)
I got a real sick one here, and i got no drawings, or any info regarding it.
Can't find one anywhere !!!!
will sort you out for doing it :grin:
Regards,
Steve :thumb:
 
[quote author="Kid Squid"]Hiya JD,

would there be any chance at all, of getting a copy of the manual from you ? ( Scan / Photocopy etc)
I got a real sick one here, and i got no drawings, or any info regarding it.
Can't find one anywhere !!!!
will sort you out for doing it :grin:
Regards,
Steve :thumb:[/quote]

Hey Steve,

My scanner at home is DOA. I've gotten a new one, but it may be a few days before I can get it up and running. When I do, I'll send you a copy, but in the mean time, I may be able to help, if you describe your issues.

John
 
[quote author="jdiamantis"]
Found the manual. This box is made in a motherboard-daughte board configuration. One of the daughterboards is the AM process card. Find it, it should be labeled.

On this card is a trimpot, labeled R321. Turn this pot fully counter clockwise, and cycle the front panel TEST/OPERATE switch to the TEST position and back to OPERATE. This will remove the phase flipper and set it to positive phase.[/quote]


Hmmm...my cards are labeled A1-A4, and none of the trimpots are labeled with more than 2 digits. I thought maybe R21 on card A3 but the only pot on A3 is R17. There is a trimpot labeled R21 on A2, perhaps that is it?

This unti also contains a PEAK CLIPPER circuit. To minimize its' effects, find trimpot R309 and turn it fully counter clockwise. On the front panel, find the POSITIVE THRESHOLD control, and turn it fully counter clockwise. If you want to remove the PEAK CLIPPER (diode clipper) completely, you'll need to remove LEDs D305 and D306. I'd also replace IC305 with something better than the 1458 that's in there.

I'm not terribly worried about the clipper, the box sounds great and i use it for its dirt.

On another note, there is a pretty steep high pass filter on the input that has a rool-off of 54db per octave, with a cutoff of 40Hz. Removing this would be beyond the scope of this post.

My unit appears to be modded, and I haven't noticed any loss of low end. Maybe someone already removed it.

Thanks for the help.
 
[quote author="Baltimore"][quote author="jdiamantis"]
Found the manual. This box is made in a motherboard-daughte board configuration. One of the daughterboards is the AM process card. Find it, it should be labeled.

On this card is a trimpot, labeled R321. Turn this pot fully counter clockwise, and cycle the front panel TEST/OPERATE switch to the TEST position and back to OPERATE. This will remove the phase flipper and set it to positive phase.[/quote]
Hmmm...my cards are labeled A1-A4, and none of the trimpots are labeled with more than 2 digits. I thought maybe R21 on card A3 but the only pot on A3 is R17. There is a trimpot labeled R21 on A2, perhaps that is it?[/quote]
The card should be labeled AM Process Board. If there is no label on it, it will be the one with 3 LED's on it. It will also have a flip flop chip, a 74C74.
 
[quote author="jdiamantis"]

The card should be labeled AM Process Board. If there is no label on it, it will be the one with 3 LED's on it. It will also have a flip flop chip, a 74C74.[/quote]

alright, the card with the 74c74 has 4 trimpots. r50, r12, r5, and r18. I'm assuming it will be r50, it is close to the 74c74, the other three are on the opposite side of the board.

Please let me know if you get the schematic scanned. I'd be interested in maybe removing some of the unnecessary bits.

Thanks again.

Kevin
 
[quote author="Baltimore"][quote author="jdiamantis"]

The card should be labeled AM Process Board. If there is no label on it, it will be the one with 3 LED's on it. It will also have a flip flop chip, a 74C74.[/quote]

alright, the card with the 74c74 has 4 trimpots. r50, r12, r5, and r18. I'm assuming it will be r50, it is close to the 74c74, the other three are on the opposite side of the board.

Please let me know if you get the schematic scanned. I'd be interested in maybe removing some of the unnecessary bits.

Thanks again.
Kevin[/quote]

The trimpot in question (a 100k) has one terminal grounded, the other connected to TP31, which is connected after the input cap on the card, a 1uf film. The wiper is connected to an opamp non-inverting input labeled IC306, a 1458. It seems as though you have a different version of the card than either my schematic or updates show.
 
Hiya John,

My scanner at home is DOA. I've gotten a new one, but it may be a few days before I can get it up and running. When I do, I'll send you a copy, but in the mean time, I may be able to help, if you describe your issues.
Much apreciated that is :grin:

I'll dig it out when I get home tomorrow, and I'll give it a run over, and see whats up eith it, I can't remember what the fault was :oops:
I just remember it not working right... :wink:

Thanks again !

Steve :thumb:
 
Alright, I found the right trimpot and it no longer flips polarity, which is very nice! This box is not very hifi sounding, definitely loses a bit of high end articulation, but it sounds nice and muscular for anything needing some beef.

Thanks so much for your help!
 
Hiya JD,

Whoa, sorry for the late responses, but i've been 'net' less for the past month.
Anyway, would still love to get hold of a copy of the manual / service data for the Multilimiter, as the one i got, doesn't pass any signal. I've only had a quick look, but looks like signal is getting there, but not coming out !!, I've also got activity on the LED boards. Sorry to sound a little vague :wink:

Kindest Regards,
Steve :thumb:
 
[quote author="Kid Squid"]Hiya JD,

Whoa, sorry for the late responses, but i've been 'net' less for the past month.
Anyway, would still love to get hold of a copy of the manual / service data for the Multilimiter, as the one i got, doesn't pass any signal. I've only had a quick look, but looks like signal is getting there, but not coming out !!, I've also got activity on the LED boards. Sorry to sound a little vague :wink:

Kindest Regards,
Steve :thumb:[/quote]

Hi Steve,

I just bought a new scanner/copier/printer/coffee maker this past weekend (finally) and if I get some time this week, it should be up and running by week's end. If so, I'll import the manual and either post, or PM copies.
 
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