tdw1 installed...input hum issue

[kristin]

hey there...love this site but never posted a question before...i searched for a q similar but could not find...so here goes.

i just installed the expansion card in my td-10 which i have had for a very long time. when everything was done i noticed a hum in my headphones. after playing with it a bit i figured out that the hum goes away when i take out the stereo input coming from my portable cd player.

any ideas???

i thought maybe i should initialize with the input plug out but i am worried that it will initialize back to the original td-10 without the wave expansion card new stuff. i guess this is a second question that relates to the above...

thanks in advance

[Shep2112]

The hum is most likely a ground problem between the cd player and the TD-10. It's unrelated to the expansion board. You mentioned it goes away when you unplug the cd player, which backs up that theory.

Do you hear it with the Input on the TD-10 all the way down? What about with the cd player volume all the way down? The problem is caused (I assume) by the fact that you're using a headphone level output into a line input.. You're basically plugging a small amplifier into an input designed for a weak signal. try the volume between 3 and 5 on the cd, and then turn up the input enough to hear it, does that help? The trick is to play the cd player loud enough that you get the noise level down, but not so loud that it overloads (and distorts) the input on the TD-10..

Does this make things clearer?
-Eric

[edm]

Re: tdw1 installed...input hum issue

Originally posted by kristin

any ideas???

I have heard, and occassionally experienced, a slight hum after upgrading a TD-10. The "acid test" is if you get erratic triggering on the "Brushes2" setting because it is the most sensitive.

I have had mixed reports about whether anything can be done about this. Once when I took a TD-10 in for repair due to this faint hum, I was told "that's normal and sometimes happens because the TDW-1 causes the TD-10 to be so much more sensitive than before." At least, this is what the repair shop guy told me that Roland told him!

I have another TD-10 in the shop right now because of this hum and erratic triggering on the Brushes2 setting that can't be suppressed with a change in sensitivity settings and have yet to get it back after at least two months, maybe three (it's been so long I can't even remember anymore). They finally sent it to Roland for them to look at and now the shop guy seems awful unavailable, but I digress...

My bottom line advice: If you can at all live with it somehow, do so as getting it fixed seems to be a nightmare waiting to happen. I have never had a "hum repair" go very well at all...

Sorry I don't have better news...

Ed

[Shep2112]

Why would a sensitivity change increase output hum though? They're 2 different things. I'll have to check the difference between both of mine I guess..

My unexpanded TD-10 is being repaired currently.. It was a store demo and had some tracking problems with the wheel, and the power switch was iffy.. They're replacing the wheel, the switch and the 3 knobs on top too.. But some of things Roland has back-ordered, so it'll be a couple more weeks they said.. (authorized repair, not Roland direct)

[edm]

[QUOTE]Originally posted by Shep2112
[B]Why would a sensitivity change increase output hum though? They're 2 different things. I'll have to check the difference between both of mine I guess..

"All boats rise with the tide." That is, when sensitivity is increased, that means more amplification which means any background noise -- including hum -- will be more pronounced.

Ed

[Shep2112]

That's basically what I started replying with, but then had to run out and just got in and luckily saw it before I got too far into my reply

I think the noise might be more noticeable with the brush sound for the simple fact that's there's less going on, and you're listening more critically/may have the levels turned up a little higher to hear it better.

Reversing the PSU sounds like a cool idea, I'd be interested in doing that. Removing it sounds like the most effective way, but also sounds cumbersome. It should be possible to isolate the circuits inside from the PSU with some index paper and aluminum foil and a wire attached to the main ground inside the unit. Then you could leave everything intact.. What do you think? The paper would keep the foil from shorting anytyhing, and then the wire lead with ground the foil to give it a purpose for being installed..

[Shep2112]

Yeah strange they don't know about that problem.

I know shielding is limited, what about using a lead sheet or something? or building a box around the psu?

I'd still like a way to rack mount my td10 into a small rack with my DI's, but I don't wanna spend $60-70 on it, and I'd like to have it be reachable from the throne, without needing a stand (ie mount it on the rack).. I guess if I had a rack case, I could move the psu to the case, but maybe the reversal is the cleanest solution. Did you have to extend any wires in the process? is it just like 6 wires or so, or is there more in this one?
-Eric

[Shep2112]

Yeah same here, I even make sure the headphones out is all the way down when not in use, just to reduce any extra possibility of noise, either from the op-amp running the phones jack or the amplified signal being close to the line outputs.. noise has never really been a noticeable thing here, even with my studio monitors.. there's a higher amount of noise in my preamps -85dB than my td-10's are putting out.. But maybe it would help a little somewhere for me

[Shep2112]

You know, now that you mention it, my Sony headphones have noise if I turn it up to the 9 o'clock position, which is about right for those phones level-wise for me. Maybe it needs cleaner output chips or something. I'll bring it into the lab at school and have one of the instructors give it a run-through. They all work at local repair centers and instruct on the side..

Mine's not 60Hz though, it's just general hash in there, like turning a guitar preamp up without playing.. just kinda yucky sounding..

[Shep2112]

Actually I meant with that Roland rack adapter. I thought making my own rack unit could be kinda cool, but the labeling will be difficult. It won't look very nice at all if I do that, but 2 rack spaces would probably do it, if I decided to go that route. I liked rack mounted gear a lot more, since you don't have to spend as much time setting it up and it doesn't get scratched as easily, etc..

I'll keep everyone posted if i come up with some kinda solution..

[inewt1]

For what it's worth, I also talked to Roland just this past week about this hum problem, and of course they'd never heard of it. The rep. said the repair techs would be the ones to see something like that. Of course, he didn't have a number for me to reach them. I posted a query here on this subject awhile back and got the same answers I'm seeing here - which was very helpful. I'm just now getting around to the pursuit!

On the headphones. I've noticed that the hum is more noticable my Sony MDR-7506's than a great set of Sennheiser's that I have. The dynamic range is better too. I ohmed them out for the heck of it, the Sonys about 4 and the Senns 8.

SG

[Shep2112]

Cool, yeah the Sony's are really nice for playing through and don't break up too easily..

Wow, 4 ohms on the Sony's, damn no wonder they're so loud.. I'll open my td-10 again one of these days and start poking around and see what I see I guess.. =)

[inewt1]

Yeah, I've been using my Sony cans steadily for the past 2 years. They were a replacement, as the first set fried a driver after about 3 months use. Replaced under warranty, and been fine ever since. Of course you know they'll croak tomorrow. Shortly after I got the replacement set, a good friend that does sound told me he had trouble with them holding up, and he'd replaced them on a couple of occasions, but these are still sounding fine.

[Shep2112]

Weird, my cousin got a set in Mexico while on tour and he's had them for quite a few years. I don't know how many gigs he played with them, but they sounded fine when I played through them 2 years ago.. He sold all of his gear to me, so he hasn't been playing in a while.. And now he wants to get some V's (He had a TD7 kit, and then got a DM5 for it).. ahh drummers..

[inewt1]

It's that fever.........my palms sweat whenever I go into a decent music store. Scared to go in just to look around, unless my credit bill is down a bit. Feel my pain?