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PCM Advice (PCM41 and PCM81 related)

High Pedality

Member
Messages
668
Hey friends,

To avoid having to comb through seemingly countless PCM threads to find a couple of simple answers/opinions I thought I'd add to the clutter.

I'll preface by saying I'm a long time effect pedal fanatic. I've owned countless vintage and boutique pedals and about everything in between but I'm very new to rack effects. Upon doing some research and talking to some friends at work, it seems like the Lexicon PCM series is highly regarded and something worth experiencing. So true to form, I get YouTube and Reverb open simultaneously and start making bad decisions.

So a couple of weeks ago, a PCM41 popped up for $400, which seemed like a pretty great price compared to the usual $700 I see around. In really great shape too. So It arrives and I'm loving it. Nothing mind melting or anything but I'm insanely impressed with how many effects you could squeeze out of this for the time and square wave, pitch shifting modulation in 1980??? I thought that was the Moog 104-m's thing, haha! Super cool. All that to say, the unit is quite noisy. Hiss and hum both. Possibly a grounding issue? Probably never been recapped? Yes, I have messed with all of the different gain staging on the unit. Different combinations of the Input dial as well the button and dial on the back of the unit. Even when I unplug my guitar from the rack, the same amount of noise persists. I'm not an electrical engineer so I really don't know but I do know enough to troubleshoot within my skill set and it's absolutely the unit that is emitting this noise. Another thing I've noticed is that the filter buttons have little to no effect whatsoever.

Fast forward and a PCM81 shows up for a killer deal and I bite on it. Should arriving here tomorrow. Seems to be celebrated for it's Concert Reverb, Circular Delays and other stuff and has quite a group surround that unit as well. I love that it's stereo so I don't have to buy two of them and I can just immediately wire it into my patchbay as my main hardware effects processor.

So that's where I'm at but I have questions...

1. Is the PCM41 an inherently noisy unit?
2. How obvious or subtle are the filter buttons?
3. Can the PCM81's delays touch on the vibe of the PCM41? (I'm expecting a lot of no's here, haha)
4. If I decide to have the unit serviced, where can I do so and what should I expect to pay?

Thanks so much, everyone.
 

Anje

Silver Supporting Member
Messages
2,061
The PCM41 is one of the few rack units I regret selling.
I don't recall it to be particularly noisy to the point of being an issue, especially in a guitar rig; but this topic can be so subjective without more real first hand actual factual data/experience in front of the rig to appreciate the level of "noise" we're talking about. If you feel it's an issue for you and the unit doesn't have any maintenance history, it could be a good idea to have it serviced. I don't have address in the US on hand, but I'm sure you could contact Lexicon for some advice and/or others will chime in here.
The filters work, but you realize they only are part of the delay feedback path don't you? Effect then can be subtle depending on the material / signal source / rig / settings you're using.
The PCM81 is great, but as we were discussing in the PCM70 thread, it will require some work to have it come close to the natural character / "grain" of the PCM41; even more so with those earlier units that had specific (and GREAT) analog I/O sections and much more ancient conversion circuits. I find those hard to beat if you're looking for some "character" and a sound that kind of naturally blends with and nicely "seats behinds" and/or "expends" the source material, if that makes sense; especially when you start driving those early units hard which emphasizes their analog sections & sound character.
 

hydroquebec

Member
Messages
2,069
4. If I decide to have the unit serviced, where can I do so and what should I expect to pay?

I don't know too much about the 41, but if you do need to have it serviced, a few of us have had good experiences with Advanced Musical Electronics in Los Angeles.
 

High Pedality

Member
Messages
668
The PCM41 is one of the few rack units I regret selling.
I don't recall it to be particularly noisy to the point of being an issue, especially in a guitar rig; but this topic can be so subjective without more real first hand actual factual data/experience in front of the rig to appreciate the level of "noise" we're talking about. If you feel it's an issue for you and the unit doesn't have any maintenance history, it could be a good idea to have it serviced. I don't have address in the US on hand, but I'm sure you could contact Lexicon for some advice and/or others will chime in here.
The filters work, but you realize they only are part of the delay feedback path don't you? Effect then can be subtle depending on the material / signal source / rig / settings you're using.
The PCM81 is great, but as we were discussing in the PCM70 thread, it will require some work to have it come close to the natural character / "grain" of the PCM41; even more so with those earlier units that had specific (and GREAT) analog I/O sections and much more ancient conversion circuits. I find those hard to beat if you're looking for some "character" and a sound that kind of naturally blends with and nicely "seats behinds" and/or "expends" the source material, if that makes sense; especially when you start driving those early units hard which emphasizes their analog sections & sound character.

Thanks for the reply. Yeah, I definitely know the filters just effect the repeats. I have pretty particular ears and I can barely tell if they're doing anything at all so it seems like they're caput. I just reached out to Harmon and they said they haven't serviced the PCM41 since 1994. Kinda figured that was going to be case.

I'll for sure look call Advanced Musical Electronics when they open today.
 

Jerrod

Gold Supporting Member
Messages
13,901
Advanced Musical Electronics is likely more convenient for you. That said, if you need another option, British Audio in Nashville did the work on my PCM-42 and were quite good.
 

ctreitzell

Member
Messages
4,078
open that PCM41 up, take some pics and share 'em here

I don't know anything about a PCM42, tho

PCM80/81 are fantastic units. Again, as we've said to death...and long before I ever got one: the factory PROGRAMs are a recording studio starting point...from 1995...they are mostly subtle or OTT

Diving into tweaking is immediately required IMO to unlock the glory

You need to be at least stereo with the PCM8x

If you haven't already, make sure you peruse
https://youtube.com/channel/UChRXGm_7EGQeIB4CbEK9t0A

Also, realize the PitchFX on the PCM8x are excellent...there are only a few pitch shift factory programs: the secret to those is the ADJUST knob

Making the Resonators work takes some effort; but once dialed in are a special experience...highly ambient and ethereal if you can get there

congrats, have fun!
 

High Pedality

Member
Messages
668
167028725_10225194785126688_6999843552357847224_n.jpg


Not exactly seeing anything funky visually. Nothing leaking, burnt, loose, etc... Weirdly enough, it smells amazing inside this thing, haha.
 

High Pedality

Member
Messages
668
So, I'm a complete bonehead.

I didn't realize these were TRS units. Before I was literally just plugging my guitar into the rack, into the an amp, hence the buzz.

Upon receiving my PCM 81 in the mail, on the back of the unit it says "balanced input/out" and then I was like, "oh man, you've gotta be kidding me". So all that today, both units are wired into my patchbay working flawlessly. I do have one question though about the PCM81. It seems to be touchy on the self oscillation front. If I turn the input up past 9'oclock on any source, doesn't matter what it starts to feedback. I'm assuming it's a setting that I'm unaware of. Any ideas?
 
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ctreitzell

Member
Messages
4,078
So, I'm a complete bonehead.

I didn't realize these were TRS units. Before I was literally just plugging my guitar into the rack, into the an amp, hence the buzz.

Upon receiving my PCM 81 in the mail, on the back of the unit it says "balanced input/out" and then I was like, "oh man, you've gotta be kidding me". So all that today, both units are wired into my patchbay working flawlessly. I do have one question though about the PCM81. It seems to be touchy on the self oscillation front. If I turn the input up past 9'oclock on any source, doesn't matter what it starts to feedback. I'm assuming it's a setting that I'm unaware of. Any ideas?
Whoops! Good you got it working.

You have a feedback loop. What is your PCM81 patched into? A computer DAW? Maybe Patch your returns to a channel? rather than the main FX return...I typically struggle with this too. My PCMs are in my guitar rack rig 95% of the time and the output feeds a separate mixer then straight to power amp and I never get a feedback loop that way.

Also, coupled with how subtle most of the FACTORY PROGRAMs are; you will find yourself cranking up the input just hear the FX. The sooner you get tweaking parameters, the better
 
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High Pedality

Member
Messages
668
Whoops! Good you got it working.

You have a feedback loop. What is your PCM81 patched into? A computer DAW? Maybe Patch your returns to a channel? rather than the main FX return...I typically struggle with this too. My PCMs are in my guitar rack rig 95% of the time and the output feeds a separate mixer then straight to power amp and I never get a feedback loop that way.

Also, coupled with how subtle most of the FACTORY PROGRAMs are; you will find yourself cranking up the input just hear the FX. The sooner you get tweaking parameters, the better

The ins and outs are wired via XLR M and F into two channels of my patch bay which all feeds into a Universal Audio X8p interface. I notice that yeah, basically what you said, if I don't have them patched on the front of the bay, the meters will just be surging all the way up and then when I patch them in, it's fine. This happens with both the 41 and 81. I'm just confused because this is literally how I have all of my other recording, outboard gear wired in and I have no issues at all. Is it just the nature of them being time based effects perhaps? Is there a setting in globals that would fix this? I can't really see any other way to wire them in to track and mix with. Thanks so much!
 

ctreitzell

Member
Messages
4,078
The ins and outs are wired via XLR M and F into two channels of my patch bay which all feeds into a Universal Audio X8p interface. I notice that yeah, basically what you said, if I don't have them patched on the front of the bay, the meters will just be surging all the way up and then when I patch them in, it's fine. This happens with both the 41 and 81. I'm just confused because this is literally how I have all of my other recording, outboard gear wired in and I have no issues at all. Is it just the nature of them being time based effects perhaps? Is there a setting in globals that would fix this? I can't really see any other way to wire them in to track and mix with. Thanks so much!
Yeah, you don't want the main return back to your DAW...if it is routed to the whole mixer FX loop and coming out your monitoring you will have issues
feed mixer channels for your returns and get rid of the feedback loop. Often the AI drivers will do this for you and that's where you need to adjust your routing; if you route in a return you'll get a feedback loop, IME

Also, you previously said "self oscillation"...which had me thinking of PCM patching, which is something else altogether!
 




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