eml 101 voltage controlled filter

1 2 3 4 5 6 7 8

A

B

C

D

87654321

D

C

B

A

+V +V+V +V

-10V -10V

-10V

-10V

-10V-V

-V

Eref

KBD1/SEQ CV

KBD2 VCF CVMIXER

FROM

Eref

FilterKBD Track

CV

EXPONENTIAL AMP 1.2V/OCTVCF Cutoff

VCF ModeLPF

BPF

HPFVCF OUT

TO VCA

LPF Out

BPF OutHPF Out

Res (Q)VCF Input

FROMVCF Mix

REF Voltage -10V

1

910

+V

-V

+15V

-15V

GND

-V

8

6

5

uA 726

+V

4K7

50K

10K

10K

470R

1K5

BC550BC550

1K5

2K2

6K8

4K7

50K

1K

10K2K49

10K

10K

10K

2K49

470R

37K4

100R1N4148

uA 7265K6

267R

1K5

22K

8K2

5K

15K

1K5

1N4148

22K1

10K

10K 470R

15K

3K6 3K6

3K6 3K6

10R 10R

1K

10R10R

1K

100K

100K15K

1K

50K

100K

100K

3K63K6 3K63K6

1M51M5

221K

100n

3p3

C

6n

C

6n

C

6n

C

6n

1n

100n

ZENER 8V2

VCF OUT MIXER

CURRENT DRIVERS

INTEGRATORS

TRANSISTOR PAIR 1 PAIR 2

TRANSISTOR

3

26

U1

TL071

3

26

U2

TL071

3

26

U3

TL071

3

26

U4

TL071

3

26

U5

TL071

3

26

U6

TL071

3

26

U7

TL071

3

26

U8

TL071

3

26

U10

TL071

3

26

U9

TL071

Cutoff

50K

50K 50K

ORIGINAL ICs :U1,3,4,5,6,10 = uA741 U2 = 1456U7,8,9 = uA748U11 = uA726TR. PAIR 1,2 = TD101

Use TL071 for all ICs, for Tr. pair use matched NPNs (~1mV) or tr. pairs likeMAT02 or 2SC1583, or you can use CA3046 or CA3086 instead, with pinsshowed in brackets, and use it for expo tranny also, but you lose uA726heated stability so you must consider using separate CA with heating andsensing transitor shceme (like shared with VCO expos). You can put discrete NPN in place of 726 and lose some temp. tracking, but it's not crucial in VCF.Q1,2 are labeled "14", use some NPNs.Capacitors C can be changed with some higher values for different effect.

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(5)(6)

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(7) (10)

EML-101 Multimode VCF1998. Drawn by Marjan Urekar