Anushri changing pitch while playing
  • Hello,

    My battle with making anushri works in a modular environment continues.
    Basically this beautiful machine (it is definitely beautiful sounding when it works) changes its pitch after some time of sending it CV sequences.
    the same behavior happens also with midi.

    Initially I thought I was sending some midi cc message that was changing the master tune and pitch but it does the same with CV and gate.

    The change is towards very low octave and lowest pitch.
    Test yesterday night was with a sequence in the C3 – A3 range that after 10 min changed to a very low octave that my tuner could not detect (it was showing G-1).

    I have opened it and checked the Voltages and I found only two things that do not really comply with the test as shown on the website:

    - Point 3: it says it should be similar to point 2 but negative…point 2 is 8.3V while point 3 is -7.2V – VCO CV: it tracks well when it is playing the right octave (if I send C3 it says 2.03 V) but as soon as it changes its behavior it show 0.4 V

    to change this behavior I usually need to go into the Latch and Hold, Jamming mode and tweak knobs until I get the right pitch and octave.
    This is not convenient while playing live of course.

    Any idea of what can go wrong? something I can check? components I have to change?

    Thank you

  • Forgot to mention
    CV and Gate sequence is sent through a calibrate CVpal via Ableton Live.

    So I am sure pitch is accurate.

  • Thanks for sharing this – very interesting!

    One of my three Anushri’s shows the same behaviour, but only after it has just been switched on AND I’m starting to play immediately. You can very clearly hear the pitch drop for about 10 seconds, after which it is too low to hear. So this must be similar to your issue, except the circumstances are a little different. When I wait a few minutes before playing (letting things warm up a bit), I have no problems.

    From you description it seems the negative side of the power circuit is not working well: my guess would be that the LT1054 is somehow damaged, or not seated properly. The latter makes most sense: temperature changes could make or break contact between the IC socket and the LT1054 pins (when these are not well connected in the first place: IC not pressed into its socket properly).

    I’m going to check up that part as soon as I get some time … first just it deeper into its socket.

  • Thanks for your insight.
    I will have a go with playing it immediately after turning on and will check the LT1054.

    I tend to wait a bit before playing it just because I want it to warm up to keep in tune :)

  • Update on the isue.

    LT1054 is correctly in place so I assume it is damaged.
    I had a n electric surge some months ago and this could be the reason.

    Also if I check volt at both side of the diode in position D2 (1N4001), I read 9.08 V on the top side and 8.34 V on the bottom.
    The DIY resource says that I should read a drop of a few mV, but we are in teh region of 700 mV in this case.

    So I am not sure if i have to buy just a new LT1054 and a diode or just the LT.

    Thanks always in advance for the tips.

  • > drop of a few mV

    few hundred mV.

    A 700mV drop is fine.

  • The voltage drop on the diode is fine – no need to change that.

    Did you try to get the LT 1054 as deep as possible into its socket?

    The 7905 could in principle also be the culprit, but that is far less likely (pretty sturdy things). Might be worth buying one of these too though (pretty cheap), just in case, if you’re ordering anyway.

  • ok, thanks to both of you.
    As usual good support.

    I have to order the components and unfortunately I cannot find them anywhere that does not charge me a whole lot of money for shipping…:(

    Asking again just in case, do you think there is some more elements I shall substitute?
    this will justify the shipping costs

  • Where are you based?

    On ebay they are a little more expensive, but shipping is usually cheaper …
    Just be careful not to oder the (tiny) SMD version :-)

    Here is one example: http://www.ebay.de/itm/1-x-LT1054CN8-Switched-Capacitor-Voltage-Converter-with-Linear-Te-DIP-8-1pcs-/160832695536

  • thansk for the tip.

    I am in UK (London).
    Found it on ebay and bought already.
    :)

  • I’ll have a look at my own misbehaving Anushri – might well be the same issue.

  • Hello again,

    So I have bought new LT1054, installed it and still the same result in point 2: -7.23V.
    SO it is not this component.
    The same value I can read at the rectifier…maybe it is the 7905 that is broken?

    While I was playing with it, I decided then to try to change the firmware and upload the latest one (0.92).
    Now it seems a little bit more stable but I am struggling to calibrate it (again…)
    the range trimmer doesn’t seem to have much effect…I am always about 50 cents apart in two different octaves.

    Anyone?
    Shall I change the 7905?
    Is the Voltage ok?

  • What is the voltage on the 7905 output?

  • Hello Oliver,

    it is still -7.23V

  • Then either your 7905 is defective, or there is a short on the board between the traces corresponding to the 7905 input and output.

  • thanks for the advice.
    I will check as soon as I go back to the studio :)

  • Hello again,

    So I have changed the 7905 and I still have the same read (-7.33V).
    I decided to connect to the eurorack power just to have a check and I read -12V at the same position (point 2).
    Is my power supply defective or not powerful enough? I think so.
    I decided to calibrate Anushri then while connected to eurorack
    No luck, I cannot make the range to work. Range is always very large (almost one semitone)

    TO be honest, I do not know what to do.
    It is either a very bad build (not mine…) or there is something else.

    Before i decide to throw it to the bin (i would like to make music more than troubleshooting) do you have any suggestions?
    Thanks

  • I guess you mean point 3, not point 2 in the above?
    Point 3 is the output of the LT1054 AND the input of the 7905, and should be the inverse of the DC voltage of your power supply minus the voltage drop over the diode.

    Please use the image on the troubleshooting page (scroll down http://mutable-instruments.net/anushri/build ) carefully: easy to confuse pins …
    The green dot (bottom pin!) is where you should measure -5V (that is the output of the 7905).

    You could post some images of the front- and backside of the part of the PCB where the 7905 etc. sit? That usually helps: a second pair of eyes does wonders :-)

    If you have cooling fins on the 7805 and 7905, make sure they do not touch.

  • Here they are

    https://drive.google.com/open?id=0B_bRjHeM5AIwLTF6LVFfdV9pcWs

  • Soldering does not look bad (though you might want to clean up between the legs of the 7905!).

    Do you measure -5v at the bottom pin of the 7905?

  • Some of the ICs (especially the smaller ones) do not seem to sit deeply in their sockets – but the view from above could be deceiving :-)

  • Thanks for looking
    I do measure -5V at the bottom of the 7905
    All ICs have been pushed in.

    The strangest thing is that sound is very full when triggered through cv gate and very weak when I use midi…

  • OK, then the power supply part seems perfectly fine.

    Have you tried reseting things to ‘factory settings’?

  • Hello,
    Just found the time to check it.
    Reset to factory, nothing change

    I try to set the offset first and no way of getting a calibration with less than 50cent apart between two octaves.
    I am using a well calibrated CVpal as CV source…no idea how can solve it.
    It seems really insane to me that this synth is so difficult to calibrate, it has always been like that.

    I am only willing of changing some other components…any idea?

  • There are some known solutions to calibration issues:
    http://mutable-instruments.net/forum/discussion/7969/can039t-calibrate-anushri-properly

    There is some tolerance on components (always), so sometimes you are unlucky and need to change one or more.

  • Done.
    It does work for the moment.
    Finger crossed.
    Thanks for your help.

  • Enjoy making music, finally!

    And keep that spare LT1054, just in case :-)

  • Well thanks but I have to say that it does not keep the tuning…I always have to go into the setting page (secodn button) and adjust the master tune and octave….

  • Do you have software compensation on or off, by default?

    Also, if you have not, the temperature does change the tuning, so you need to allow for a warm-up period. It is analog, after all …

    See the VCO tuning section in the manual.

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