# \#1007 midimuso midi-cv **URL:** \ **Category:** FAQ\ **Created:** [July 15, 2020, 1:06pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446 "2020-07-15T13:06:09Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![lookmumnocomputer](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/lookmumnocomputer/32/23_2.png) [@lookmumnocomputer](https://lookmumnocomputer.discourse.group/u/lookmumnocomputer)\ **Post date:** [July 15, 2020, 1:06pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/1 "2020-07-15T13:06:09Z")
Right! its on its way, I figured id make the thread! this module took a bit of teething, so I’m sorry for the wait but surprisingly still keeping to a module a month!!! give or take a week here and there. I’m putting together the documentation and videos etc for it today/tomorrow. everything including the listing should be up on Friday. fingers crossed!! it comes with the CV12 chip with slightly modified code including return to bass characteristics, defaulting on the mode 4 channel Mono, and also C as 0v (the standard actually has A as 0v), I bought a bulk from Midimuso and will include with the listing, and also it comes with the 2 4504’s as it was pointed out to me that they need to be Texas instrument ones, as other manufacturers 4504’s showed slightly erratic behaviour. so to save some head scratching I got a whole bunch of them too. ---
**Author:** ![twinturbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@twinturbo](https://lookmumnocomputer.discourse.group/u/twinturbo)\ **Post date:** [July 15, 2020, 3:39pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/2 "2020-07-15T15:39:25Z")
ahh super. I think this will be an enabler for a lot of us that may have a suitable keyboard 🙂 ---
**Author:** ![fredrik](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/fredrik/32/682_2.png) [@fredrik](https://lookmumnocomputer.discourse.group/u/fredrik)\ **Post date:** [July 15, 2020, 3:51pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/3 "2020-07-15T15:51:17Z")
> [@lookmumnocomputer](#): > > other manufacturers 4504’s showed slightly erratic behaviour (or more likely, the design depends on undefined behaviour (I mean, we’ve already seen the rather creative use of a non-regulating LM317 in the original muso 😃)) EDIT: Wait, the reference schematics use MC14504, but that’s not a Texas component? Confused. ---
**Author:** ![d42kn355](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/d42kn355/32/273_2.png) [@d42kn355](https://lookmumnocomputer.discourse.group/u/d42kn355)\ **Post date:** [July 15, 2020, 4:52pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/4 "2020-07-15T16:52:14Z")
Thank the gods… this has been hanging on my wall for a while now 😛 ![image](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/1/16e4fce057622989d349711602d0bff9c2332767.jpeg) ---
**Author:** ![d42kn355](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/d42kn355/32/273_2.png) [@d42kn355](https://lookmumnocomputer.discourse.group/u/d42kn355)\ **Post date:** [July 15, 2020, 4:55pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/5 "2020-07-15T16:55:13Z")
I’m totally going to use my old ass Miracle Piano Keyboard lol… Just need to disable its onboard speaker… ---
**Author:** ![Bitnik](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/bitnik/32/274_2.png) [@Bitnik](https://lookmumnocomputer.discourse.group/u/Bitnik)\ **Post date:** [July 15, 2020, 5:05pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/6 "2020-07-15T17:05:42Z")
> [@d42kn355](#): > > Miracle Piano Keyboard Oh we had one of those when genius son was a little boy. Had to give it away when we moved back from London. ---
**Author:** ![lookmumnocomputer](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/lookmumnocomputer/32/23_2.png) [@lookmumnocomputer](https://lookmumnocomputer.discourse.group/u/lookmumnocomputer)\ **Post date:** [July 16, 2020, 5:48pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/7 "2020-07-16T17:48:03Z")
yes sorry fredrik that schematic had the wrong component designation. ---
**Author:** ![lookmumnocomputer](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/lookmumnocomputer/32/23_2.png) [@lookmumnocomputer](https://lookmumnocomputer.discourse.group/u/lookmumnocomputer)\ **Post date:** [July 16, 2020, 5:49pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/8 "2020-07-16T17:49:17Z")
but yes that’s is also very true! I mean it doesn’t seem to. and to be honest I have not tried it with other brands and I may very well do so!± infact im going to order some and see what happens. I may aswell see what midimuso is on about. before I question the voodoo gods!±!! ---
**Author:** ![lookmumnocomputer](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/lookmumnocomputer/32/23_2.png) [@lookmumnocomputer](https://lookmumnocomputer.discourse.group/u/lookmumnocomputer)\ **Post date:** [July 16, 2020, 5:49pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/9 "2020-07-16T17:49:57Z")
a classic! the miracle piano ha ---
**Author:** ![heckseven](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/heckseven/32/23483_2.png) [@heckseven](https://lookmumnocomputer.discourse.group/u/heckseven)\ **Post date:** [July 17, 2020, 3:30pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/10 "2020-07-17T15:30:18Z")
It’s up! [https://store.lookmumnocomputer.com/collections/all/products/1007-midimuso-midi-cv-module-pcb-panel-chipset](https://store.lookmumnocomputer.com/collections/all/products/1007-midimuso-midi-cv-module-pcb-panel-chipset) ---
**Author:** ![ChristianBloch](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/christianbloch/32/56_2.png) [@ChristianBloch](https://lookmumnocomputer.discourse.group/u/ChristianBloch)\ **Post date:** [July 17, 2020, 4:31pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/11 "2020-07-17T16:31:22Z")
![Thank you for your purchase! - LOOK MUM NO COMPUTER - Checkout](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/d/d96cde6ff751dd5878a335c4be31a1e9019bdcc1.png) Was all set to order a third VCO too, but it’s back ordered. ---
**Author:** ![Riggidyboo](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/riggidyboo/32/10_2.png) [@Riggidyboo](https://lookmumnocomputer.discourse.group/u/Riggidyboo)\ **Post date:** [July 17, 2020, 4:37pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/12 "2020-07-17T16:37:35Z")
I’ll start a Tayda list ---
**Author:** ![heckseven](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/heckseven/32/23483_2.png) [@heckseven](https://lookmumnocomputer.discourse.group/u/heckseven)\ **Post date:** [July 17, 2020, 4:53pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/13 "2020-07-17T16:53:30Z")
Yeah. I got the last one I think. For now. I hope more are on the way. The same for the mixer. ---
**Author:** ![lookmumnocomputer](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/lookmumnocomputer/32/23_2.png) [@lookmumnocomputer](https://lookmumnocomputer.discourse.group/u/lookmumnocomputer)\ **Post date:** [July 17, 2020, 5:14pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/14 "2020-07-17T17:14:46Z")
aaah sorry on the VCO’s! they are back next week! I hadn’t realised until a bit too late on those ones!! Im pulling together a video on the midi module at the minute, it shouldd be up on Sunday, running through the build and calibration etc. ---
**Author:** ![Riggidyboo](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/riggidyboo/32/10_2.png) [@Riggidyboo](https://lookmumnocomputer.discourse.group/u/Riggidyboo)\ **Post date:** [July 17, 2020, 5:54pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/15 "2020-07-17T17:54:39Z")
I think this covers it [https://www.taydaelectronics.com/tl431acl-tl431-precision-shunt-regulator.html](https://www.taydaelectronics.com/tl431acl-tl431-precision-shunt-regulator.html) [https://www.taydaelectronics.com/40-pin-2-54-mm-single-row-pin-header-strip.html](https://www.taydaelectronics.com/40-pin-2-54-mm-single-row-pin-header-strip.html) [https://www.taydaelectronics.com/10-pin-box-header-connector-2-54mm.html](https://www.taydaelectronics.com/10-pin-box-header-connector-2-54mm.html) [https://www.taydaelectronics.com/10uf-25v-105c-radial-electrolytic-capacitor-5x11mm.html](https://www.taydaelectronics.com/10uf-25v-105c-radial-electrolytic-capacitor-5x11mm.html) [https://www.taydaelectronics.com/a-553-0-1uf-50v-ceramic-disc-capacitor-pkg-of-10.html](https://www.taydaelectronics.com/a-553-0-1uf-50v-ceramic-disc-capacitor-pkg-of-10.html) [https://www.taydaelectronics.com/10-x-22pf-50v-ceramic-disc-capacitor-pkg-of-10.html](https://www.taydaelectronics.com/10-x-22pf-50v-ceramic-disc-capacitor-pkg-of-10.html) [https://www.taydaelectronics.com/0-01uf-50v-80-20-ceramic-disc-capacitor.html](https://www.taydaelectronics.com/0-01uf-50v-80-20-ceramic-disc-capacitor.html) [https://www.taydaelectronics.com/1uf-50v-radial-tantalum-capacitor.html](https://www.taydaelectronics.com/1uf-50v-radial-tantalum-capacitor.html) [https://www.taydaelectronics.com/1n4148-switching-signal-diode.html](https://www.taydaelectronics.com/1n4148-switching-signal-diode.html) [https://www.taydaelectronics.com/connectors-sockets/wafer-housing-crimp-terminal/serie-2500-2-54mm/wafer-connector-2-54mm-3-pins.html](https://www.taydaelectronics.com/connectors-sockets/wafer-housing-crimp-terminal/serie-2500-2-54mm/wafer-connector-2-54mm-3-pins.html) [https://www.taydaelectronics.com/connectors-sockets/wafer-housing-crimp-terminal/serie-2500-2-54mm/housing-connector-2-54mm-3-pins.html](https://www.taydaelectronics.com/connectors-sockets/wafer-housing-crimp-terminal/serie-2500-2-54mm/housing-connector-2-54mm-3-pins.html) [https://www.taydaelectronics.com/connectors-sockets/wafer-housing-crimp-terminal/serie-2500-2-54mm/wafer-connector-2-54mm-2-pins.html](https://www.taydaelectronics.com/connectors-sockets/wafer-housing-crimp-terminal/serie-2500-2-54mm/wafer-connector-2-54mm-2-pins.html) [https://www.taydaelectronics.com/connectors-sockets/wafer-housing-crimp-terminal/serie-2500-2-54mm/housing-connector-2-54mm-2-pins.html](https://www.taydaelectronics.com/connectors-sockets/wafer-housing-crimp-terminal/serie-2500-2-54mm/housing-connector-2-54mm-2-pins.html) [https://www.taydaelectronics.com/connectors-sockets/wafer-housing-crimp-terminal/serie-2500-2-54mm/crimp-terminal-connector-2-54mm.html](https://www.taydaelectronics.com/connectors-sockets/wafer-housing-crimp-terminal/serie-2500-2-54mm/crimp-terminal-connector-2-54mm.html) [https://www.taydaelectronics.com/resistor-10-ohm-1-4w-1-metal-film-pkg-of-10.html](https://www.taydaelectronics.com/resistor-10-ohm-1-4w-1-metal-film-pkg-of-10.html) [https://www.taydaelectronics.com/resistor-5-1k-ohm-1-4w-1-metal-film-pkg-of-10.html](https://www.taydaelectronics.com/resistor-5-1k-ohm-1-4w-1-metal-film-pkg-of-10.html) [https://www.taydaelectronics.com/resistor-220-ohm-1-4w-1-metal-film-pkg-of-10.html](https://www.taydaelectronics.com/resistor-220-ohm-1-4w-1-metal-film-pkg-of-10.html) [https://www.taydaelectronics.com/10-x-resistor-100k-ohm-1-4w-1-metal-film-pkg-of-10.html](https://www.taydaelectronics.com/10-x-resistor-100k-ohm-1-4w-1-metal-film-pkg-of-10.html) [https://www.taydaelectronics.com/10-x-resistor-10k-ohm-1-4w-1-metal-film-pkg-of-10.html](https://www.taydaelectronics.com/10-x-resistor-10k-ohm-1-4w-1-metal-film-pkg-of-10.html) [https://www.taydaelectronics.com/10-x-resistor-1k-ohm-1-4w-1-metal-film-pkg-of-10.html](https://www.taydaelectronics.com/10-x-resistor-1k-ohm-1-4w-1-metal-film-pkg-of-10.html) [https://www.taydaelectronics.com/10-x-resistor-270-ohm-1-4w-1-metal-film-pkg-of-10.html](https://www.taydaelectronics.com/10-x-resistor-270-ohm-1-4w-1-metal-film-pkg-of-10.html) [https://www.taydaelectronics.com/14-pin-dip-ic-socket-adaptor-solder-type.html](https://www.taydaelectronics.com/14-pin-dip-ic-socket-adaptor-solder-type.html) [https://www.taydaelectronics.com/16-pin-dip-ic-socket-adaptor-solder-type.html](https://www.taydaelectronics.com/16-pin-dip-ic-socket-adaptor-solder-type.html) [https://www.taydaelectronics.com/6n137-high-speed-logic-gate-optocouples-ic.html](https://www.taydaelectronics.com/6n137-high-speed-logic-gate-optocouples-ic.html) [https://www.taydaelectronics.com/tl074-quad-operational-amplifier-j-fet-pdip-14-tl074cn.html](https://www.taydaelectronics.com/tl074-quad-operational-amplifier-j-fet-pdip-14-tl074cn.html) [https://www.taydaelectronics.com/14-pin-dip-ic-socket-adaptor-solder-type.html](https://www.taydaelectronics.com/14-pin-dip-ic-socket-adaptor-solder-type.html) could not find this on Tayda > **[FAIRCHILD DM74LS14N HEX INVERTER WITH SCHMITT TRIGGER 14PIN QTY = 1 | eBay](https://www.ebay.co.uk/itm/FAIRCHILD-DM74LS14N-HEX-INVERTER-WITH-SCHMITT-TRIGGER-14PIN-QTY-1/114094504883?hash=item1a908ffbb3:g:xUgAAOSw~QdeNY69)** > > HEX INVERTER WITH SCHMITT TRIGGER. MANUFACTURER = FAIRCHILD. alternate: [https://www.taydaelectronics.com/74hc14-7414-ic-hex-schmitt-inverter-high-speed-cmos-ttl.html](https://www.taydaelectronics.com/74hc14-7414-ic-hex-schmitt-inverter-high-speed-cmos-ttl.html) [https://www.taydaelectronics.com/16-000-mhz-16-mhz-crystal-hc-49-s-low-profile.html](https://www.taydaelectronics.com/16-000-mhz-16-mhz-crystal-hc-49-s-low-profile.html) [https://www.taydaelectronics.com/l78l05acz-l78l05-78l05-5-volts-100ma-voltage-regulator-ic.html](https://www.taydaelectronics.com/l78l05acz-l78l05-78l05-5-volts-100ma-voltage-regulator-ic.html) [https://www.taydaelectronics.com/5k-ohm-trimmer-potentiometer-cermet-25-turns-3296w.html](https://www.taydaelectronics.com/5k-ohm-trimmer-potentiometer-cermet-25-turns-3296w.html) [https://www.taydaelectronics.com/10k-ohm-trimmer-potentiometer-cermet-25-turns-3296w.html](https://www.taydaelectronics.com/10k-ohm-trimmer-potentiometer-cermet-25-turns-3296w.html) [https://www.taydaelectronics.com/brass-standoff-spacer-screw-hex-male-m3x10mm-silver.html](https://www.taydaelectronics.com/brass-standoff-spacer-screw-hex-male-m3x10mm-silver.html) [https://www.taydaelectronics.com/nut-3mm-for-screw-m3.html](https://www.taydaelectronics.com/nut-3mm-for-screw-m3.html) [https://www.taydaelectronics.com/phillips-round-head-screw-m3-0-5mm-heat-sink-to-220-to-247-transistor.html](https://www.taydaelectronics.com/phillips-round-head-screw-m3-0-5mm-heat-sink-to-220-to-247-transistor.html) [https://www.taydaelectronics.com/8-pin-2-54-mm-single-row-female-pin-header.html](https://www.taydaelectronics.com/8-pin-2-54-mm-single-row-female-pin-header.html) [https://www.taydaelectronics.com/2n3904-npn-general-propose-transistor.html](https://www.taydaelectronics.com/2n3904-npn-general-propose-transistor.html) [https://www.taydaelectronics.com/6-35mm-1-4-stereo-phone-jack.html](https://www.taydaelectronics.com/6-35mm-1-4-stereo-phone-jack.html) [https://www.taydaelectronics.com/leds/round-leds/5mm-leds/red/led-5mm-red.html](https://www.taydaelectronics.com/leds/round-leds/5mm-leds/red/led-5mm-red.html) [https://www.taydaelectronics.com/resistor-100-ohm-1-4w-1-metal-film-pkg-of-10.html](https://www.taydaelectronics.com/resistor-100-ohm-1-4w-1-metal-film-pkg-of-10.html) [https://www.taydaelectronics.com/tl074-quad-operational-amplifier-j-fet-pdip-14-tl074cn.html](https://www.taydaelectronics.com/tl074-quad-operational-amplifier-j-fet-pdip-14-tl074cn.html) [https://www.taydaelectronics.com/14-pin-dip-ic-socket-adaptor-solder-type.html](https://www.taydaelectronics.com/14-pin-dip-ic-socket-adaptor-solder-type.html) [https://www.taydaelectronics.com/tl072-low-noise-j-fet-dual-op-amp-ic.html](https://www.taydaelectronics.com/tl072-low-noise-j-fet-dual-op-amp-ic.html) [https://www.taydaelectronics.com/8-pin-dip-ic-socket-adaptor-solder-type.html](https://www.taydaelectronics.com/8-pin-dip-ic-socket-adaptor-solder-type.html) Tayda does not have the midi sockets, alternative: > **[Amazon.com: CESS DIN Female 5-Pin Jack Socket Connector Panel Mount Soldering -...](https://www.amazon.com/CESS-Female-Socket-Connector-Soldering/dp/B01G0Q3XLK/ref=sr_1_2?dchild=1&keywords=midi%2Bsocket&qid=1595009575&sr=8-2)** > > 5-Pin DIN Female Socket Panel Chassis Connector in Nickel or > **["Neutrik Rean NYS325 5 Pin DIN Female Chassis Connector" from...](https://www.parts-express.com/neutrik-rean-nys325-5-pin-din-female-chassis-connector--092-154)** > > Neutrik Rean NYS325 5 Pin DIN Female Chassis Connector ---
**Author:** ![twinturbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@twinturbo](https://lookmumnocomputer.discourse.group/u/twinturbo)\ **Post date:** [July 17, 2020, 5:56pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/16 "2020-07-17T17:56:46Z")
Order is in 🙂 I need to take stock of my build and testing progress. I have forgotten what modules are tested and fully working. ---
**Author:** ![antoine.pasde2](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/antoine.pasde2/32/326_2.png) [@antoine.pasde2](https://lookmumnocomputer.discourse.group/u/antoine.pasde2)\ **Post date:** [July 17, 2020, 6:07pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/17 "2020-07-17T18:07:37Z")
> [@Riggidyboo](#): > > could not find this on Tayda FAIRCHILD-DM74LS14N-HEX-INVERTER-WITH-SCHMITT-TRIGGER-14PIN The 74HC14 should do just fine as it is capable of ±4mA and this circuit won’t use more than about 1mA. > **[74HC14 7414 IC HEX SCHMITT INVERTER High Speed CMOS TTL](https://www.taydaelectronics.com/74hc14-7414-ic-hex-schmitt-inverter-high-speed-cmos-ttl.html)** > > VARIOUS - Get It Fast - Same Day Shipping ---
**Author:** ![Riggidyboo](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/riggidyboo/32/10_2.png) [@Riggidyboo](https://lookmumnocomputer.discourse.group/u/Riggidyboo)\ **Post date:** [July 17, 2020, 6:09pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/18 "2020-07-17T18:09:10Z")
I was hoping someone would chime in with that useful information Thanks ---
**Author:** ![lookmumnocomputer](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/lookmumnocomputer/32/23_2.png) [@lookmumnocomputer](https://lookmumnocomputer.discourse.group/u/lookmumnocomputer)\ **Post date:** [July 17, 2020, 6:21pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/19 "2020-07-17T18:21:07Z")
thanks Antoine! the all seeing eye!!! ---
**Author:** ![antoine.pasde2](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/antoine.pasde2/32/326_2.png) [@antoine.pasde2](https://lookmumnocomputer.discourse.group/u/antoine.pasde2)\ **Post date:** [July 17, 2020, 6:21pm UTC](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446/20 "2020-07-17T18:21:57Z")
The 74HC14 is fine for driving the MIDI THRU outputs. ![image](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/5/5e9559cd3bdb4ce7d59ae2c819584ba7162ba227.png) Surprisingly it might be a bit marginal for driving the LED’s transistor, which pulls about (5-0.7)/1k = 4.3mA, but the 74HC14 is still better than the 74LS14 which is only rated for 0.4mA for a high output. I would just replace that 1k resistor by 1.2K to be on the safe side. Shouldn’t affect the LED’s brightness significantly. EDIT: I was going off the Texas Instrument data sheet, according to Tayda’s web page, the 74HC14 can drive ±5.2mA so it’s OK as-is with the 1K resistor. The 74LS14 on the other hand could use a 12K resistor… which would still probably give a plenty bright LED as the transistor would still be saturated. [Next page](https://lookmumnocomputer.discourse.group/t/1007-midimuso-midi-cv/1446.md?page=2)