Howdee!

This may be the wrong forum so feel free to move?
I recently got a tr808 for cheap(ish) but it has a couple of issues! the slight cosmetic stuff I can deal with, but distortion on the toms, clap and snare i'm less tolerant of!

More specifically there is heavy distortion on the toms (not on the congas though, which use the same outputs) and the snare and clap seem to have a distorted reverb tail to them? this only becomes relevant on the snare when the 'snappy' is brought in.

Anyone have any Ideas? I spoke to a tech guy and he suggested a problem with the output stages or a psu thing?

Anyone experienced this before, and am I likely to be able to fix/get it fixed without it costing me an arm and some legs?

Cheers
Steve

My 808 has seen better days, but it does play back fine. However; due to the years of filth that have worked its way in, at times adjusting the pitch on the tom/conga can lead to unpredictable responses, and I have found a simple switch cleaner can resolve this issue. But your problem sounds a bit worse. I've never opened up my 808 as I've seen pictures and it looks like a scary job! I would certainly get yours looked at as it sounds like it needs some TLC.

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http://soundcloud.com/richie-royale
http://www.mixcrate.com/richieroyale

Also, have you tried the individual outputs and the main? I would expect the problem to be present on both outputs if it is a problem with the individual signal generators.

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http://soundcloud.com/richie-royale
http://www.mixcrate.com/richieroyale

Hey
Yeah I tried it on both outputs its the same!
I will get it looked at, I just hope its not going to be either terminal, or a case of finding expensive replacement parts!

I'm sure it is fixable, just budget for labour costs as it might take some time to find the fault unless your technician is well versed with an 808.

These links might be of use.

http://www.dinsync.info/2010/02/roland-tr-808-service-manual.html
http://www.technologytransplant.com/index.php?cPath=5_13 Parts

http://fileshare.eshop.bg/equipment_mfg/Roland_5.html This says it is a link to the 808 service manual, but I've not checked the downloads available at the end of the link.

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http://soundcloud.com/richie-royale
http://www.mixcrate.com/richieroyale

Thanks!!
Usfull links!

He's pretty well versed with most things (he was a tecky at Real World I believe) so should know what to do!
He fixed up my Linn LM2 recently so I trust his skill!!

There is a noise source that contributes to the sound of the toms and the snare (my 808 is modded to give me separate control over this noise) - it's possible you may have a problem here, which may be an easy fix.

hth

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Adam Inglis
A Disco Ate My BABY!

ahh! This sounds like it could be the one!
I'll get this looked into!

Does anyone more knowledgeable than me on such matters know or can tell from the service manual ( http://www.dinsync.info/2010/02/roland-tr-808-service-manual.html ) what the part is.
The Noise generater I mean?
Or indeed where on the circuit of said item the problem could lay?
Thanks!
If I can try and track it down before it goes to service it could save some time (and therefor cash!)

Ok I found the thing on the schematic on page 7 but it doesn't have a part number on that page and i can't find it elsewhere, but I don't know enough really!
Any help is massively appreciated!
Steve

The noise circuit is on p8, and is shown at the right hand side of the page. There are a couple of labels coming off marked "WN" for white noise, and "PN" for pink noise. You'll notice the white noise generator was slightly altered and the updated circuit is shown too. It's basically a transistor, an op-amp and a few resistors and capacitors - nothing special, nothing expensive, an easily replaced if duff. That's if the culprit is indeed that circuit. If the noise is distorting, there's a trimpot in there that you see is marked with a suggested level for the noise output. It might be worth checking it's set correctly.

Hey thats great!
You seem to know what your talking about!!
I'm sure the problem must be in that circuit because looking at the schem its only sounds which are using the white or pink noise as part of them!
Interestingly it isn't effecting the marracas though, which is on the same board as the clap?
maybe if I upload samples of the effected sounds you could get a better idea as to weather the problem could be here?
Thanks so much!
I really could do with getting this sorted!
Steve

Here is a link to the sounds!
All recorded dry as nun and un-compressed!

http://www.mediafire.com/?iuu2f4bm9pyw318

Thanks again!

Thanks for the audio. It may be that the problem is still present on the maracas, but it's hidden by the other aspects of the sound. I'm not that familiar with the 808's maracas to be honest!

I still say the first thing to check would be the level of the noise output. If you read p.14 of the service notes, you'll see a table of what to check for each voice. If you're confident and able to meter something with the unit open and switched on, checking the noise level is easy. If you're not sure about it at all, give it to someone who is.

Without taking a proper look at things, I'd guess that either the noise level is set a little too high - but not much - or some other component in the noise circuit is causing the distortion. My reason for thinking this is that the problem is common to all the sounds using noise. Have another close listen to the maracas and see. I'm not saying that's definitely it - but it's where I'd start.

Hey yeah this is possible with the marracas that I wouldn't hear it as its not meant to have any release to the sound (the artificial reverb) so it may not have a chance to show as with the others?
I'll look at that trim pot!
Thanks again for the help!
I'll let you know how I get on!
Steve

Quote vetsdiggy:

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Here is a link to the sounds!
All recorded dry as nun and un-compressed!

http://www.mediafire.com/?iuu2f4bm9pyw318

Thanks again!

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Ha ha - now that sounds just like mine does when I have the noise pot turned up! Nice and crunchy!
The maracas has it's own high pass filter that is prob taking out a lot of that low and mid range crunch that the filters on the other voices are leaving in...

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Adam Inglis
A Disco Ate My BABY!