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Post by dagogo on Apr 24, 2019 9:04:09 GMT -6
Hi, I am a longtime lurker and have learned much here. I hate to have a problem post as my first, but I am having a bit of a dilemma and do not know how to resolve and if there are any ideas here I would certainly appreciate any input.
I bought a used Heritage MCM-8 500 chassis. During testing, everything seemed fine, until I installed two Helios 69 modules. The audio output is badly distorted, but ONLY when there are 2 Helios mods installed. One Helios mod sounds fine, as do Electrodyne & Purple modules, no problems with those.
I have recreated the issue several times and checked with XLR outs, Dsub out, & summing mixer out...all the same result... distorted signal through both Helios outputs once a second Helios mod is installed....position does not matter. I have another 500 chassis and tested the Helios mods in those, they sound normal, like they always have.
I emailed Heritage, they responded to check the pinout of the helios modules...."it may be that the ‘compression link’ pin is being used for some other feature and, being those linked by default, causing any interference."
So, where to find a pin out of the Helios 69? I called vintage king and am waiting to hear back but I would be curious if anyone here has any ideas. To me, it seems like an issue with the Heritage unit. I've used the Helios modules in 2 other 500 Chassis and have never had a problem. Why would the Heritage unit be dealing with the link pin outs differently than other manufactures? Thanks for any input.
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Post by christopher on Apr 24, 2019 10:32:24 GMT -6
Hi, and welcome!
Before going to far, if you haven't already make sure to try the Heritage plugged into a different outlet, preferably different circuit, also use the IEC cable from your other 500 box to rule that out as well.
My R6 lunchbox sounds like the world's most expensive walkie talkie when its plugged into the same strip my computer is on. Plugging into other outlets fixed it, hopefully you'll get lucky.
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Post by dagogo on Apr 24, 2019 11:36:12 GMT -6
Hi Thanks!
Good idea, just realized since I had to move the unit yesterday to test with DSUB snake, I actually did use a different circuit and IEC cable with same result. I have been using synth output from JDI direct box and a condenser mic to test with same results...
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Post by svart on Apr 24, 2019 12:04:25 GMT -6
Sounds like you're maxing out your power supply. Heritage has this disclaimer: "Maximum audio rails current: 1.6A per rail, or 400mA per rail per slot, whatever is reached first" Which IS a lot, but if you're able to run a handful of modules UNTIL you plug another in, that says to me you're reaching some kind of hard limit. You might take out a couple of the other modules and try JUST the two helios modules and see if they can work alone. As for a "compression link", I'm not sure what they mean by that. you can try to contact what's left of Helios here (I think): www.helios-audio.com/ |
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Post by Johnkenn on Apr 24, 2019 12:37:07 GMT -6
So it’s not just the normal lack of headroom from the Helios units? With a mic, I could overload those pres into ugly distortion at like -20db.
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Post by drbill on Apr 24, 2019 13:11:46 GMT -6
Try swapping Helios #1 with Helios #2 and try one helios (#2) by itself and see if it's clean - to make sure that #2 alone is clean. If it is clean, that's one weird problem.
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Post by dagogo on Apr 24, 2019 13:20:18 GMT -6
Thanks a lot for the link! It doesn't seem like a power supply issue to me, because the problem happens when the only the 2 modules loaded in the rack are the Helios modules. So, with either Helios installed as only module, good sound. When both Helios installed, both signals are weak/distorted and there are no other mods installed. With the rack fully loaded with other brand modules and phantom engaged there are no issues.
In combing through some old Helios threads, I did read something about how Tony Arnold had something setup (or idea?) that you would be able to interface the eq in the pre module directly with the compressor he was working on...but I don't know if that was for the 500 series or the Helios rack...or whether anything ever came of it. In any case, I'm not aware of any jumpers with the 500 module itself.
I guess it's kind of hard to describe distortion...but this is not a "normal" distorted sound, like when something is overdriven. It's a weak, thin, buzzy, horrible sounding, "something's wrong with the signal" kind of distortion.
edit:
Yes, Either module alone is clean! Also, both sound great (normal) in my other chassis.
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Post by Johnkenn on Apr 24, 2019 13:34:44 GMT -6
That would be the sound of Helios distortion. Lol. Really not usable at all. More like bad clipping. I actually had to pad the Helios’ to get USABLE sounds...and then used a compressor for makeup gain. Excellent tone after that, though. Believe it’s from not having an output transformer. Anyway, if you have one in and aren’t getting the distortion at the same place when you have two in, there’s obviously something else going on though.
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Post by jcoutu1 on Apr 24, 2019 13:40:38 GMT -6
Put them in slots 1 and 3 rather than consecutive slots. I had a pair of 500 modules that didn't play well next to each other. I think that had to do with the link as well.
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Post by dagogo on Apr 24, 2019 16:00:34 GMT -6
That's a good idea...I've had them in slots 4/5, 5/6, 1/8, 7/8 & maybe 6/7 will experiment some more as have nothing to lose...
OK, testing again and found some more weirdness...
Helios mods in 7/8. I have source plugged into 8 (nothing input to 7). I plugged the dsub line 7 output into patchbay and I hear the audio yet I have nothing plugged into that input! I also hear the audio through the dsub channel 8 output.
To rule out snake issue, I went back to XLR, when plugged into channel 8 output, I can hear the clicks as I adjust the gain on Helios module in 7.
I then reversed (signal in line 7, can here gain clicks from module in 8 though nothing hooked up to inputs or outputs to module 8.
I wonder if I monitored a single modules output, but put a reversed phase input signal into the 2nd module if that would be telling?
I think John may be right...it could very well be just the Helios clipping sound. When I padded down the source (with the 2 modules installed), I did get a relatively clean signal, though almost no level at all, I had to dime the monitor controller just to hear it. Somehow the signals seem to be merging within the chassis...and sort of half canceling & distorting the output signal. Weird that it seems to happen only with the Helios mods.
Incidentally, no channels are active within the summing buss and pushing those buttons doesn't change anything.
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ericn
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Post by ericn on Apr 24, 2019 17:30:23 GMT -6
Welcome to RGO, the Heritage Rack has a separate PSU regular for each slot so while I doubt moving stuff around will help it can’t hurt.
While you can’t contact Helios, you can contact Heritage and they might very well be interested in solving this so that the next guy isn’t banging his head against the wall, it can’t hurt.
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Post by svart on Apr 24, 2019 18:01:03 GMT -6
That's a good idea...I've had them in slots 4/5, 5/6, 1/8, 7/8 & maybe 6/7 will experiment some more as have nothing to lose... OK, testing again and found some more weirdness... Helios mods in 7/8. I have source plugged into 8 (nothing input to 7). I plugged the dsub line 7 output into patchbay and I hear the audio yet I have nothing plugged into that input! I also hear the audio through the dsub channel 8 output. To rule out snake issue, I went back to XLR, when plugged into channel 8 output, I can hear the clicks as I adjust the gain on Helios module in 7. I then reversed (signal in line 7, can here gain clicks from module in 8 though nothing hooked up to inputs or outputs to module 8. I wonder if I monitored a single modules output, but put a reversed phase input signal into the 2nd module if that would be telling? I think John may be right...it could very well be just the Helios clipping sound. When I padded down the source (with the 2 modules installed), I did get a relatively clean signal, though almost no level at all, I had to dime the monitor controller just to hear it. Somehow the signals seem to be merging within the chassis...and sort of half canceling & distorting the output signal. Weird that it seems to happen only with the Helios mods. Incidentally, no channels are active within the summing buss and pushing those buttons doesn't change anything. Sounds like there is indeed some kind of link going on between the two. Probably best to contact Helios about it now. |
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Post by Johnkenn on Apr 25, 2019 15:52:57 GMT -6
You should send them to me for a year loan so I can check them out in my API Rack  |
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Post by dagogo on Apr 26, 2019 11:45:22 GMT -6
I'd probably send them for a week if you had an MCM8...hehe. I did receive a polite email response from the Helios link posted above saying they don't have any documentation available "for the reissue from a 3rd party (Tony Arnold)"...evidently they didn't take over his stuff. I'm working on a couple of other things and will report back.
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Post by matt@IAA on Apr 26, 2019 12:18:04 GMT -6
I'd probably send them for a week if you had an MCM8...hehe. I did receive a polite email response from the Helios link posted above saying they don't have any documentation available "for the reissue from a 3rd party (Tony Arnold)"...evidently they didn't take over his stuff. I'm working on a couple of other things and will report back. Do you have any documentation on them? Schematic or even a block diagram? I have some Helios docs from the net but don’t know how close they are to yours. If you take some photos I can probably figure out the pin out for you by tracing the pcb. |
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Post by stratboy on Apr 26, 2019 13:31:42 GMT -6
My Bento 10 has some link features that make it not like some 2-slot modules in odd-numbered spaces. Not the same problem as you’re experiencing, but it leads to my (and others’) suggestion to experiment more with slot placement.
Also, I would keep after VK. They’re good folks and a Heritage dealer. They used to sell the new Helios. So if anybody is going to have the ability to get to the bottom of this, it’s them.
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Post by dagogo on Apr 27, 2019 12:01:49 GMT -6
No I don't have any documentation at all. They did not come with manuals and I haven't been able to locate anything thus far. I agree VK is probably the best bet for this. They did take my info and I have purchased from them and am hoping they come through. With all of their past association with the Helios reissues I can't believe they don't have a schematic much less a pin out.
That is a great offer dogears thanks. If I come up empty at VK I will take some photos. It's certainly something that would probably be helpful to others down the line as well.
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