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<div dir="ltr" data-setdir="false">I just tried as AS3340 in my JP-6 and changing the PW does affect the pitch (mostly noticeable in the higher octaves). The autotune can compensate for it though (adjust PW, hit Tune button).</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Doug <br></div><div dir="ltr" data-setdir="false">synthparts.com<br></div><div><br></div>
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On Thursday, December 19, 2019, 3:12:35 PM PST, ColinMuirDorward <colindorward@gmail.com> wrote:
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<div><div id="ydpea96d023yiv1930414145"><div><div><div dir="ltr">Out of curiosity, does anyone have an mks80 rev4 and/or Jupiter 6 they could test for this problem? </div><div dir="ltr"><br clear="none"></div><div dir="ltr">My brother sold his mks80 rev4 already, but claims the pitch error was quite bad in his unit.</div><div dir="ltr"><br clear="none"></div><div dir="ltr">In the next model, the rev5, Roland apparently switched the 3340 for a proprietary VCO chip. <br clear="none"></div><div dir="ltr"><br clear="none"></div><div dir="ltr">Colin</div><div dir="ltr"><br clear="none"></div></div><br clear="none"><div class="ydpea96d023yiv1930414145yqt9618605964" id="ydpea96d023yiv1930414145yqt22023"><div class="ydpea96d023yiv1930414145gmail_quote"><div class="ydpea96d023yiv1930414145gmail_attr" dir="ltr">On Thu, Dec 19, 2019 at 3:48 PM Tom Wiltshire <<a shape="rect" href="mailto:tom@electricdruid.net" rel="nofollow" target="_blank">tom@electricdruid.net</a>> wrote:<br clear="none"></div><blockquote class="ydpea96d023yiv1930414145gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex;"><div>My own view of it is that if you want cheap, you buy the Alfa AS3340. If you want original and can afford it, you buy the CEM3340 G. The V3340 falls somewhere in the middle and therefore doesn’t offer a unique selling point for DIYers.<div><br clear="none"></div><div>Coolaudio don’t care, since Behringer needs tons of ‘em! ;)</div><div><br clear="none"></div><div><div>Tom</div>
<div><br clear="none"><blockquote type="cite"><div>On 19 Dec 2019, at 13:53, ColinMuirDorward <<a shape="rect" href="mailto:colindorward@gmail.com" rel="nofollow" target="_blank">colindorward@gmail.com</a>> wrote:</div><br clear="none"><div><div dir="ltr"><div>I didn't see a lot of discussion on this topic include the v3340. Not sure if people had already collected the CEM and AS versions by the time the Vs came out, or what, but the coolaudios don't seem to be on as many work benches.</div><div> I just checked a neutron and no surprise that I could not find any pitch error there. <br clear="none"></div><div>I have a lot of as3340s, so when my next prototype comes in, I could check for error variation between chips.</div><div><br clear="none"></div><div>Colin<br clear="none"></div></div><br clear="none"><div class="ydpea96d023yiv1930414145gmail_quote"><div class="ydpea96d023yiv1930414145gmail_attr" dir="ltr">On Thu, Dec 19, 2019 at 10:01 AM Tom Wiltshire <<a shape="rect" href="mailto:tom@electricdruid.net" rel="nofollow" target="_blank">tom@electricdruid.net</a>> wrote:<br clear="none"></div><blockquote class="ydpea96d023yiv1930414145gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex;"><div>A quick test on my Pro-One doesn’t reveal any tuning problem. I routed the LFO to PW on oscillator A, then listened to Oscillator A’s ramp wave alone (so no beating to confuse things) and couldn’t hear any difference, even with maximum mod depth and maximum LFO rate. Checking the output on the oscilloscope showed no pitch variation either.<div><br clear="none"></div><div>That said, there’s some evidence Sequential *did* select 3340s. The ones regarded as “not good enough” were used for LFO duties, and if you check the PCBs you’ll see paint blobs on those ones. I’ve never seen anything documenting what the tests were though. Maybe they just built the things and swapped out any that caused a problem, put a blob on them, and then used them later where it wouldn’t matter.</div><div><br clear="none"></div><div>A more interesting test which I might get to later would be an A/B/C comparison on my 3340 test board between CEM3340 G, AS3340, and V3340. Despite having all three chips on the shelf, I’ve never actually done this.</div><div><br clear="none"></div><div>Tom</div><div><br clear="none"><div>
<div><div style="font-family:Helvetica;font-size:12px;font-style:normal;font-weight:normal;letter-spacing:normal;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;">==================<br clear="none"> Electric Druid<br clear="none">Synth & Stompbox DIY<br clear="none">==================</div></div>
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<div><br clear="none"><blockquote type="cite"><div>On 19 Dec 2019, at 12:06, Mattias Rickardsson <<a shape="rect" href="mailto:mr@analogue.org" rel="nofollow" target="_blank">mr@analogue.org</a>> wrote:</div><br clear="none"><div><div>I remember talking to Dieter Doepfer about this back in the day... Ah, here it is:<div><br clear="none"></div><div>/mr</div><div><br clear="none"></div><div><br clear="none"></div><div><br clear="none"></div><div><span style="font-family:sans-serif;font-size:12.8px;">At 17:52 2003-02-02, Dieter Doepfer wrote:</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">> > -----Ursprüngliche Nachricht-----</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">> > Von: Mattias Rickardsson </span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">> > Gesendet am: Mittwoch, 29. Januar 2003 11:10</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">> > An: </span><a shape="rect" href="mailto:hardware@doepfer.de" style="text-decoration-line:none;color:rgb(66,133,244);font-family:sans-serif;font-size:12.8px;" rel="nofollow" target="_blank">hardware@doepfer.de</a><span style="font-family:sans-serif;font-size:12.8px;">; </span><a shape="rect" href="mailto:technik@doepfer.de" style="text-decoration-line:none;color:rgb(66,133,244);font-family:sans-serif;font-size:12.8px;" rel="nofollow" target="_blank">technik@doepfer.de</a><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">> > Betreff: A-111 problem? (PW affects Frequency)</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">> ></span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">> > Hi,</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">> > I have a problem with several of my A-111 High-End VCOs:</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">> ></span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">> > The pulsewidth (both PW knob and PWM input+knob) affects the frequency</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">> > of the oscillator. I.e., when turning the PW knob or PWM modulating with</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">> > a slow LFO, the frequency makes a clearly audible change.</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">> >...</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">></span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">>Dear Mattias,</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">>I forward your inquiry to our A-111 specialist Matthias Marass</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">>(mailto:</span><a shape="rect" href="mailto:keyboards@doepfer.de" style="text-decoration-line:none;color:rgb(66,133,244);font-family:sans-serif;font-size:12.8px;" rel="nofollow" target="_blank">keyboards@doepfer.de</a><span style="font-family:sans-serif;font-size:12.8px;">)</span><span style="font-family:sans-serif;font-size:12.8px;">. He is responsible</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">>for the final tests and repairs</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">>of the A-111. He will answer you directly.</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">At 15:36 2003-06-11, Döpfer Musikelektronik - Keyboardservice wrote:</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">Dear Mr. Rickardsson,</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">the influence of the external and internal PW</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">control voltage to the oscillator frequency is a</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">problem of nearly 80..90% of the CEM3340 we ever</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">used. Unfortunately there is no chance to repair</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">this problem. The only way would be a strict</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">selection of the CEM3340 circuits.</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">...</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">Best regards,</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><span style="font-family:sans-serif;font-size:12.8px;">Matthias Marass</span><br style="font-family:sans-serif;font-size:12.8px;" clear="none"><a shape="rect" href="mailto:keyboards@doepfer.de" style="text-decoration-line:none;color:rgb(66,133,244);font-family:sans-serif;font-size:12.8px;" rel="nofollow" target="_blank">keyboards@doepfer.de</a><br clear="none"></div><div><br clear="none"></div><div><br clear="none"></div><div><br clear="none"></div><div><br clear="none"></div></div><br clear="none"><div class="ydpea96d023yiv1930414145gmail_quote"><div class="ydpea96d023yiv1930414145gmail_attr" dir="ltr">Den tors 19 dec. 2019 10:42Oakley Sound via Synth-diy <<a shape="rect" href="mailto:synth-diy@synth-diy.org" rel="nofollow" target="_blank">synth-diy@synth-diy.org</a>> skrev:<br clear="none"></div><blockquote class="ydpea96d023yiv1930414145gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex;"> > ... "So as a conclusion the goal is to have on pin3 as close as <br clear="none">
possible to -5V and the PWM to tune error will not manifest itself."<br clear="none">
<br clear="none">
I did not find this to be the case since I always run any 3340 circuit <br clear="none">
from a precision 5V reference. The solution for me was to get the <br clear="none">
CEM3340 rev G. The CEM3340 has the detune too, it's just that it is <br clear="none">
quite small. I can't remember exactly, but I think it's in the region of <br clear="none">
+/-1 cent. It would almost certainly be there on the SH-101.<br clear="none">
<br clear="none">
Alfa's solution is to use the newer AS3340-HYB. The other thing to do is <br clear="none">
make your own triangle or saw to pulse wave convertor from an op-amp or <br clear="none">
comparator external to the chip.<br clear="none">
<br clear="none">
When repairing an OB-Sx I found that the AS3340 did not work well as a <br clear="none">
sub for the original CEM3340. Even with the various resistor changes <br clear="none">
required to get the AS3340 to work properly, the VCOs in last three <br clear="none">
voice card positions on the motherboard displayed a very audible pitch <br clear="none">
instability at pulse widths at less than 45%. Clearly, there was some <br clear="none">
layout issue but although I tried all sorts of things (including bus bar <br clear="none">
0V and liberal dousing of capacitance) it wouldn't solve the problem. <br clear="none">
Again, the solution was to replace all the VCOs with CEM3340 G.<br clear="none">
<br clear="none">
Tony<br clear="none">
<br clear="none">
<a shape="rect" href="http://www.oakleysound.com/" rel="nofollow" target="_blank">www.oakleysound.com</a><br clear="none">
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