#2700 twin t drums

twinturbo · 2021-05-13T06:41:52.064Z

Ahh Super… Still need to build that case as nothing is set up.

fredrik · 2021-05-16T17:48:00.147Z

#2700 TWIN T DRUMMR

This is the PCB and Panel set to build the #2700 TWIN T DRUMMER, A Twin T Drum module based on early organ drum voices, primarily the Rhythm Generator described in practical electronics early 1978. The info on this project is over here :-...

Price: GBP 28.00

Caustic · 2021-05-16T19:10:27.155Z

Tail end of latest video has a demo!

lookmumnocomputer · 2021-05-16T19:11:52.048Z

just putting together the documentation! and schematic for peeps who wanna build it with other means!

thanks to the eagle eyes :D.

twinturbo · 2021-05-16T21:20:51.154Z

order is in… ( twin t to 20 )

Riggidyboo · 2021-05-17T20:01:16.517Z

BOM for US folks (scroll right to see links) IC was still sourced from UK. Pots and inductor took some sourcing, so maybe order those 1st.
Edit: The .47uf(470nf) caps in my list are huge. Probably should get these box ones instead.

taydaelectronics.com

0.47uF 470nF 63V 5% Polyester Film Box Type Capacitor

ARCOTRONICS/KEMET- Get It Fast - Same Day Shipping

Price: USD 0.16

RythmCONTROL
Id	Designator	Package	Quantity	Designation	Supplier and ref
23	FB1,FB2	Metal Film Resistor 1/4	2	10r	10 OHM 1/4W 1% Metal Film Resistor Royal OHM Top Quality
27	R1,R9,R10,R14,R16,R29,R31,R45,R46,R50,R58,R62	Metal Film Resistor 1/4	12	1k	1K OHM 1/4W 1% Metal Film Resistor Royal OHM Top Quality
33	R23	Metal Film Resistor 1/4	1	2k2	2.2K OHM 1/4W 1% Metal Film Resistor Royal OHM Top Quality
28	R2,R17,R32,R47	Metal Film Resistor 1/4	4	150k	150K OHM 1/4W 1% Metal Film Resistor Royal OHM Top Quality
29	R3,R8,R18,R24,R33,R39,R48,R55	Metal Film Resistor 1/4	8	68k	68K OHM 1/4W 1% Metal Film Resistor Royal OHM Top Quality
30	R4,R5,R19,R20,R34,R35,R51,R52	Metal Film Resistor 1/4	8	10k	10K OHM 1/4W 1% Metal Film Resistor Royal OHM Top Quality
31	R6,R15,R21,R37,R53	Metal Film Resistor 1/4	5	27k	27K OHM 1/4W 1% Metal Film Resistor Royal OHM Top Quality
32	R7,R12,R22,R38,R54	Metal Film Resistor 1/4	5	47k	47K OHM 1/4W 1% Metal Film Resistor Royal OHM Top Quality
34	R25,R41,R42,R56,R59,R60,R61,R11,R13,R26,R43,R40,R44,R63,R64,R65	Metal Film Resistor 1/4	16	100k	100K OHM 1/4W 1% Metal Film Resistor Royal OHM Top Quality
35	R27,R28,R30	Metal Film Resistor 1/4	3	1M	1M OHM 1/4W 1% Metal Film Resistor Royal OHM Top Quality
36	R36	Metal Film Resistor 1/4	1	4k7	4.7K OHM 1/4W 1% Metal Film Resistor
47	R49,R57	Metal Film Resistor 1/4	2	18k	18K OHM 1/4W 1% Metal Film Resistor Royal OHM Top Quality
1	C9,C6	Polyester Capacitor	2	15nf	15nF 0.015uF 100V 5% JFA Mylar Film Capacitors
2	C1,C10,C8,C7,C4	Polyester Capacitor	5	47nf	47nF 0.047uF 100V 5% JFA Mylar Film Capacitors
3	C17,C20	Polyester Capacitor	2	1n5	1.5nF 0.0015uF 100V 5% Mylar Film Capacitors
4	C13,C14	Polyester Capacitor	2	33nf	33nF 0.033uF 100V 5% Mylar Film Capacitors
5	C15,C21,C22,C23,C28	Polyester Capacitor/Ceramic Capacitor	5	470nf	470nF 0.47uF 100V 5% Mylar Film Capacitors
6	C2,C3	Polyester Capacitor	2	150nf	150nF 0.15uF 100V 5% Mylar Film Capacitors
7	C16,C12	Polyester Capacitor	2	10nf	10nF 0.01uF 100V 5% JFA Mylar Film Capacitors
8	C24,C5	Polyester Capacitor	2	100n	100nF 0.1uF 100V 5% Mylar Film Capacitors
9	C11,C18,C19	Polyester Capacitor	1	4.7nf	4.7nF 0.0047uF 100V 5% Mylar Film Capacitors
	Capacitors Make them polyester or anything fancy above ceramic
	If you end up having to chuck in a couple of ceramics it won’t be the
	End of the world, but ceramics may introduce the odd unwanted noise
	Here and there, it aint the end of the world but its a bit of a funky one
12	100mh L1	100mh Inductor	1	L	100mH 6x8mm 10% Tolerance Shielded Radial Lead Inductors \| eBay or https://www.digikey.com/en/products/detail/RLB1014-104KL/RLB1014-104KL-ND/2561370?itemSeq=365039179
13	Q1,Q2,Q3	2n3904 Transistor	3	2N3904	2N3904 NPN General Propose Transistor
14	U4	Voltage Regulator	1	L78L05_TO92	L78L05ACZ L78L05 78L05 +5 VOLTS 100mA Voltage Regulator IC
15	C25,C26,C27	Electrolytic Capacitor	3	10uf	10uF 50V 105C Radial Electrolytic Capacitor 5x11mm
16	D1,D4,D5,D9,D14,D17	LED_D5.0mm	6		https://www.taydaelectronics.com/catalogsearch/result/?q=5mm+led
17	D2,D3,D6,D7,D10,D11,D12,D13,D15,D16,D18,D19	D_DO-35_SOD27_P7.62mm_Horizontal	12	1n4148	Search results for: '1n4148'
24	J1	PinSocket_1x10_P2.54mm_Vertical	1	MAINBOARDINPUT	40 Pin Male 2.54mm Single Row Pin Header Break away Round Pin Gold Plated
25	J2	PinSocket_1x10_P2.54mm_Vertical	1	MAINBOARDOUTPUT	40 Pin 2.54 mm Single Row Female Pin Header or 10 Pin 2.54 mm Single Row Female Pin Header
26	J3	Multicomp_MC9A12-1034_2x05_P2.54mm_Vertical	1	POWER INPUT	10 Pin Box Header Connector 2.54mm
37	RV1,RV3,RV5,RV7	Alps Potentiomter B470k/ B500k/ even B1M if your funky	4	KICK B470k	https://modularaddict.com/parts/potentiometers-3/9mm-round-shaft-6-35mm-vertical-potentiometers B500k
38	RV2,RV4,RV6,RV8	1M Trimpot, 470k is also fine if you can find them	4	1M KTrim	1M OHM TRIMMER POTENTIOMETER CERMET 25 TURNS 3296W
45	U1	DIP-14_W7.62mm_LongPads	1	4011AE	CD4011AE RCA INTEGRATED CIRCUIT X5pcs \| eBay
	4011AE has much better decay to the more modern 4011B.	Still plenty of the AE type about, treat yourself :D.
46	U2,U3	DIP-14_W7.62mm_LongPads	2	TL074	TL074 Quad Operational Amplifier J-FET PDIP-14 TL074CN
	BIG JACK SOCKETS		12		6.35mm 1/4" Stereo Phone Jack

taydaelectronics.com

14 pin DIP IC Socket Adaptor Solder Type

GTK - Get It Fast - Same Day Shipping

Price: USD 0.05

fredrik · 2021-05-17T20:09:03.883Z

Riggidyboo:

4011AE has much better decay to the more modern 4011B.

Did anyone get around to test a UBE? (that’s the modern version of AE).

lookmumnocomputer · 2021-05-17T20:23:13.573Z

sorry fredrik I missed that in the thread! nice… learnt something new I didn’t realise they offered modern and unbuffered. I have ordered some and when they turn up ill pop one in and I will let you know

lookmumnocomputer · 2021-05-17T20:23:56.778Z

thanks riggidyboo I will share a link to this on the main page!

Dud · 2021-05-17T21:59:12.921Z

BratAttack · 2021-05-21T01:25:04.515Z

Well, ordered a couple off these and some dual vcas. Looking forward to adding some more modules.

lookmumnocomputer · 2021-05-24T11:37:27.004Z

Ok so the 4011UBE 's turned up that @fredrik asked to test.

yes they do work however they do have more decay. If you drop the 4011UBE into the circuit as it is, the decay knob on max would cause the drums to oscillate, so in order for it to still be controllable to your liking with the preset potentiometers may I suggest to swap

R2 150k
R17 150k
R32 150k
R47 150k

with a higher resistance, I think the best bet is 470k which will give the preset potentiometer plenty of travel for you to adjust the decay knob to your liking.

I will make sure to drop these resistors in to double check for myself later on today.

twinturbo · 2021-05-24T20:00:26.662Z

100% have shipped mine … the 4011’s have turned up . need to check the rest of the BOM.

Twin T’s Twin T drums comming shortly

lookmumnocomputer · 2021-05-24T20:51:42.125Z

good to know! I have footage of building it I will have it commentated within the next few days, the only thing I suggest build notes wise if you tackle it before is solder the 3 resistors on the front of the control pcb first. this project got pretty busy so some resistors are on the front, you’ll know which as the footprints are on the other side

Beau · 2021-05-27T17:35:28.095Z

just built mine and all ok except the lights. They work fine if I plug a lfo in, but they dont light up if I use my beatstep. Any ideas anyone? Thanks, Beau

fredrik · 2021-05-27T17:54:57.506Z

If I’m reading the schematics correctly, the input LEDs just shows the input level with no pulse stretching, so it could just be that the pulses are too short to notice.

(no idea what the beatstep is using, but synth triggers tend to be 1-5 ms or so, which may not be noticeable)

Riggidyboo · 2021-05-28T21:33:56.587Z

@lookmumnocomputer 2700 BOM says Qty 1 for 4.7nf cap, but there is 3.

lookmumnocomputer · 2021-05-28T21:49:06.011Z

aha thanks for that riggidyboo

EDIT ITS NOW FIXED CHEEERZZZ

lookmumnocomputer · 2021-05-28T21:52:16.408Z

yes to backup what fredrik is saying, the led is just mirroring the trigger inputs. interesting they don’t light up for your beat step. as the beat step standard gate is still wide enough to see. in the ones I built I tested it and was happy enough with the LED’s even on short triggers. however this may be because I use super bright LED’s I did not think to try dimmer LED’s with it. ill have a look and see if just piggybacking some capacitors might solve your problem let me give it a go.

but @beau is it sounding alright? glad it is actually working!

Beau · 2021-05-29T16:04:06.394Z

yeah it works fine Sam. It lights up if I plug an LFO into it, just not the beatstep