The Official Sequential/DSI Forum

Oscillator Issues

Re: Oscillator Issues
« Reply #40 on: September 06, 2017, 10:59:56 AM »
Hi Propheteer-

This is a public forum for mostly customer interaction, with some interaction from DSI. If you have additional information or want a personal response, the fastest way to achieve that is always going to be by contacting us directly.

We've already commented on this particular topic here:

http://forum.davesmithinstruments.com/index.php/topic,1573.msg19989.html#msg19989

If you have new troubleshooting information please contact us directly. Rest assured our silence does not imply disregard. Because this issue is still being evaluated and classified, we have no new comments other than what has already been stated.
SEQUENTIAL

Re: Oscillator Issues
« Reply #41 on: September 06, 2017, 06:44:14 PM »
Okay, after speaking with Dave Smith support and following their instructions, the problem has been revealed to be a faulty voice chip on the main board. :(

So sadly not something that can be fixed by a firmware update.

I'm waiting to hear what my options are, but I think I'll probably have to return the Rev2 (sigh).

I don't think I could fit a new motherboard, that'd be a bit too techy for me.

Oh well, I feel better that at least it's been decisively diagnosed.

I await instructions from Dave Smith for what's the quickest way to have it resolved.

For anyone interested my final video shows the problem (and the rather neat inside of a REV2 too! :)

https://youtu.be/uxAHS151G0s

Propheteer

Re: Oscillator Issues
« Reply #42 on: September 06, 2017, 10:24:30 PM »
Thanks for letting us know, this is what I feared too. While in my case it wasn't something that hit me over the head as it was a lesser fault, it's still a fault. Which means the synth is also worth less as an asset should I wish to sell it in future. So looks like I'll have to return it to my retailer. Love the synth but don't think I'll risk it again. Real shame. :( was the first DSI synth I'd ever really liked and they turn out faulty!

I'd have no problem fitting a new motherboard personally (esp on a modern synth like this with basically an empty chassis; have already seen inside on DSI insta), I've fixed vintage synths for years and had to fit similar things to other modern synths that had issues, but what I can't be doing with is putting down deposits for boards, returning old ones (at my expense) insured to the US etc on a BRAND NEW SYNTH.

If i'd have gone through support as you did I think it would have taken to long to miss my 'easy return' window with the retailer. THe fact that even one other person doesn't have this issue on the 8 voice should have tipped me off. I may contact DSI anyway just to get it in writing. 1500 isn't really joke money. :(

BTW in my case i think that 'bit of saw' on the triangle is actually the filter on one voice that opens up too far, if I turn down the cut off I can make the 'sawy' one almost match the tone of the others (though they sound duller). With this all in one synth chips the oscs and filter are all there so a bad chip can manifest as filter or waveform issues just like an old dying Juno 106's voice chips!
« Last Edit: September 06, 2017, 11:02:39 PM by Propheteer »

Propheteer

Re: Oscillator Issues
« Reply #43 on: September 06, 2017, 11:09:28 PM »
I'm waiting to hear what my options are, but I think I'll probably have to return the Rev2 (sigh).

https://youtu.be/uxAHS151G0s

Yeah for me that 'no sound' on a key happens when shape mod is on full (not 50%) but same thing, just one voice does it the rest are fine.

Are you going to get another one? Would you miss it now if you decided not to replace it with another REV2? I love this synth but I'm worried that these faults may develop over time even if a 'new' unit shows no signs of faults. And unlike old synths where you could fix them yourself in years to come with simple components or plug in chips, these are all tightly packed SMT components almost impossible to be user fixed (much like the cursed Andromeda A6 and its legendary faults)

Propheteer

Re: Oscillator issues and bugs, or do I have a faulty synth?
« Reply #44 on: September 06, 2017, 11:24:36 PM »
Additionally, if there is a problem DSI should just confirm if its a bug, reproduce-able, publish the root cause and corrective action. Publishing a knowledge base/FAQ
of issues on the web (with affected serial#) would also help.

Personally,  I don't have much confidence in American factories and many are sub-par to China factories (have seen many). 

Have to agree with this a bit. I've had nothing but quality issues with every US made synth I've bought in recent years (Moog and now DSI basically). Both had severe faults that needed or would need replacement parts and work on my end.

I also agree that they could have just said in this thread if these synths were 'meant' to be doing this, through some really undesirable but as designed feature (flaw) rather than try to bury it through the usual 'contact us at support' to keep it off the forums! Only by talking to other users openly do we find patterns (much like the Sub 37's famous filter pot issue) that can confirm pretty quickly if something is right or not.

I have contacted DSI and my retailer this morning to get the ball rolling. Was about to start recording with the REV2 over the next 2 weeks or more so this is quite annoying/disappointing.

Re: Oscillator Issues
« Reply #45 on: September 07, 2017, 02:33:44 AM »
I have an issue with the pulse wave. When shape is set to 99% there is no sound across the keys except for four or five keys in the upper range. Same on both oscillators. I have already contacted support.
IMac Mid 2013, Cubase 9Pro, Prophet Rev 2 8voice

Propheteer

Re: Oscillator Issues
« Reply #46 on: September 07, 2017, 03:01:45 AM »
I suppose one upside of getting a new mainboard from DSI is that it can be pre-tested by them on all waveforms across all keys and certified before sending it, if we return synths to get another one there's no guarantee the next one won't have similar faults too (and other faults like keybed or encoders - so if we have a good one physically which I do I'm loathe to swap it for one that could have physical issues just to get a good voice board).

I think I want to keep the synth, it's so useful and sounds glorious even up against certain VCO synths I've got here. Would miss it for sure. The only pain is costs of sending the old voice board back to the US (from UK), that won't come cheap and adds to the cost of the synth which is still brand new. Will see what DSI say.

Re: Oscillator Issues
« Reply #47 on: September 07, 2017, 04:19:03 AM »
I suppose one upside of getting a new mainboard from DSI is that it can be pre-tested by them on all waveforms across all keys and certified before sending it, if we return synths to get another one there's no guarantee the next one won't have similar faults too (and other faults like keybed or encoders - so if we have a good one physically which I do I'm loathe to swap it for one that could have physical issues just to get a good voice board).

I think I want to keep the synth, it's so useful and sounds glorious even up against certain VCO synths I've got here. Would miss it for sure. The only pain is costs of sending the old voice board back to the US (from UK), that won't come cheap and adds to the cost of the synth which is still brand new. Will see what DSI say.

Yes I too am in the UK and like you would rather not have to return it.
I'm in Nottingham and retailer I purchased from in London, so I'd have to repack it and pay a courier to send it back and knowing my luck it'd get lost!!!
 
Everything else on my Rev2 seems to work perfectly so like you I'd be reluctant to change it for another one.
It appears most Rev2's have niggles of some kind so if I could get this sorted without the hassle of sending it back that'd be the ideal solution for me.

I've informed my retailer I intend to return it, as my 14 day no quibble return/refund option expires tomorrow, so hopefully DSI will be in contact today to let me know what my options are.

Yes I'd love to keep the synth, but tbh I don't want the hassle of diagnosing another unit which I feel might be the case if I get another, so if I can't 'swap it out', I'll probably just return it for a full refund and look for something else instead. :(

Will wait on an update from DS support.


Propheteer

Re: Oscillator Issues
« Reply #48 on: September 07, 2017, 05:17:28 AM »
yeah, understood. I know the mainboard should be very simple to swap in though, some screws out of the case, out of the board, put new board in then do it all back up again. Not a complex synth at all internally. I can't seem to find anything else that quite hits the mark like the REV2, god knows I've looked long enough (and owned enough synths new and old). REV2 just seems to have that magic combination of every feature I've wanted + good analog sound + decent price + 5 octaves and all the modern luxuries like LFO/Clock sync on everything.

Re: Oscillator Issues
« Reply #49 on: September 07, 2017, 06:36:13 AM »
Appreciate the replies gents. Ill smoke this over and see how it plays out for me.

Re: Oscillator Issues
« Reply #50 on: September 07, 2017, 06:54:42 AM »
yeah, understood. I know the mainboard should be very simple to swap in though, some screws out of the case, out of the board, put new board in then do it all back up again. Not a complex synth at all internally.

Well if replacing the main board is as simple as you say, then that would be my preference tbh.
I'm no expert but I'm relatively capable with a screw driver and that way I get to keep the synth too. :)
As like you, I think it's great and it looks super cool sat next to my beloved Prophet 12 too!  ;D

Re: Oscillator Issues
« Reply #51 on: September 07, 2017, 07:18:42 AM »
Actually, after watching that video back, there's even some inconsistencies with the sound in that board before the note drops, so it's probably actually 5 voice chips that are effected, all be it not as severely as the dud.
Listen from 1m 48s and you'll hear an audible change at 1m 53s point.
God I'm a geek!  ;)
« Last Edit: September 07, 2017, 07:25:50 AM by jazzygb1 »

Re: Oscillator Issues
« Reply #52 on: September 07, 2017, 06:20:07 PM »
I suppose one upside of getting a new mainboard from DSI is that it can be pre-tested by them on all waveforms across all keys and certified before sending it, if we return synths to get another one there's no guarantee the next one won't have similar faults too (and other faults like keybed or encoders - so if we have a good one physically which I do I'm loathe to swap it for one that could have physical issues just to get a good voice board).

I think I want to keep the synth, it's so useful and sounds glorious even up against certain VCO synths I've got here. Would miss it for sure. The only pain is costs of sending the old voice board back to the US (from UK), that won't come cheap and adds to the cost of the synth which is still brand new. Will see what DSI say.


I think I've already mentioned this... but I was having the buzzy saw on 4/16 voices.  I replaced my main board.... and I still have the same problem.  So I wouldn't be optimistic.  If replacing the board fixes this problem please let me know.  Ha, I could try a third.  That said replacing the main voice board was pretty easy.  Just have to remove a bunch of screws, then unplug a few things... Not very difficult.

Propheteer

Re: Oscillator Issues
« Reply #53 on: September 07, 2017, 08:46:42 PM »
Everything concerning the voicing of the synth is on that board (unless you have an add-on voice card too) so it's strange that your problem didn't go away, was it exactly the same? same voice too? Unless there's some kind of per-voice control logic chip on the controller (upper) boards I can't see how swapping to a new mainboard would be the same, unless the board they sent you they didn't test properly either? which would be a schoolboy error of epic proportions!

Yeah the mainboard looks easy as anything. When you've fixed leaking battery damage on a Polysix mainboard and brought back an AX-80 from the dead due to the power supply area being completely ruined, popping in a new board in is like making a sandwich :)

Had to fit a new control panel to my Sub 37 which was easy enough but more tricky than the REV2 mainboard as had a ton of bolts on every pot + awkward panel access.
« Last Edit: September 07, 2017, 08:48:19 PM by Propheteer »

Re: Oscillator Issues
« Reply #54 on: September 08, 2017, 11:19:31 AM »
Ok after following the steps mentionned above i retested it and i fo have on 4/8 voices a very faint buzzing it is hardly noticable but it's there, also i noticed my PW on the Square wave getting thin the upper the keyboard i go if set to 90%. I am seriously considering giving it back and take my money now :(

Re: Oscillator Issues
« Reply #55 on: September 08, 2017, 11:55:07 AM »
Hi Alphacode909-

Have you contacted our customer support directly? support (at) davesmithinstruments.com
SEQUENTIAL

Re: Oscillator Issues
« Reply #56 on: September 08, 2017, 05:15:20 PM »
Everything concerning the voicing of the synth is on that board (unless you have an add-on voice card too) so it's strange that your problem didn't go away, was it exactly the same? same voice too? Unless there's some kind of per-voice control logic chip on the controller (upper) boards I can't see how swapping to a new mainboard would be the same, unless the board they sent you they didn't test properly either? which would be a schoolboy error of epic proportions!

Yeah the mainboard looks easy as anything. When you've fixed leaking battery damage on a Polysix mainboard and brought back an AX-80 from the dead due to the power supply area being completely ruined, popping in a new board in is like making a sandwich :)

Had to fit a new control panel to my Sub 37 which was easy enough but more tricky than the REV2 mainboard as had a ton of bolts on every pot + awkward panel access.

I do have a 16 voice, but it's definitely the meain board.  Removing the  expansion board didn't make a difference.  And it's exactly the same.  4/16 voices have a buzziness to their triangle.  Which makes me wonder how prevalent the problem is.  And made me hesitate to swap out a voice board again.  That said, as mentioned above, it's not really noticeable when you actually get down to programming.  But it's really annoying to know that it's there.

Propheteer

Re: Oscillator Issues
« Reply #57 on: September 08, 2017, 10:54:59 PM »
well I contacted DSI two days ago, only had the ticket number no actual reply yet and i'm on my last day of return window... love the synth but something isn't right here for so many people to have this issue.

Re: Oscillator Issues
« Reply #58 on: September 09, 2017, 06:49:23 AM »
Hi Alphacode909-

Have you contacted our customer support directly? support (at) davesmithinstruments.com

Thank you , i am sorry to say but i decided to send it back today on the 30day money back scheme my shop offers. This is clearly a big issue and in my opinion INACCEPTABLE for an instrument of such price for at least DSI to not acknowledge it publically.

I am afraid the Curtis chips will fail after some time and i will have lots of trouble to get replacement parts from US.  This is my 2nd product from DSI i have issues with so i am not taking risks. Most of your synths are really really great and i love my Pro2 and will keep it forever, but doubt i will ever buy a DSI product in the future.

Re: Oscillator Issues
« Reply #59 on: September 09, 2017, 04:28:19 PM »
Hi Alphacode909-

Have you contacted our customer support directly? support (at) davesmithinstruments.com

Thank you , i am sorry to say but i decided to send it back today on the 30day money back scheme my shop offers. This is clearly a big issue and in my opinion INACCEPTABLE for an instrument of such price for at least DSI to not acknowledge it publically.

I am afraid the Curtis chips will fail after some time and i will have lots of trouble to get replacement parts from US.  This is my 2nd product from DSI i have issues with so i am not taking risks. Most of your synths are really really great and i love my Pro2 and will keep it forever, but doubt i will ever buy a DSI product in the future.

That's a shame as their synths sound yummy! :)

However I can totally understand it considering your experiences.

I wouldn't worry about the Curtis chips failing though, as they are pretty much ubiquitous in DSI synths and have no record of failing to my knowledge.

I think the problems with the REV2 stem from their choice of voice chips. Certainly based on this thread they'd seem to be a bit fickle at least.

My retailer is replacing mine with a brand new replacement, so fingers crossed it'll be a case of second time lucky for me! :)

Though I'd be lying if I said I didn't have reservations about the replacement also having issues, but I love my Prophet 12 and I really like the REV2 too, so I'm giving it the benefit of a doubt.

I do feel long term maybe Dave Smith will either have to change the voice chip design and probably up the cost as result.

Only time will tell.

I know they had problems with the Prophet 08 back in the day and they sorted them out eventually, hopefully they'll do the same with the REV2 too. :)
« Last Edit: September 09, 2017, 04:38:28 PM by jazzygb1 »