Disclaimer
This is just an amateur pedal with no intention for profit or to infringe any trademark.Tube Screamer is a trademark of Hoshino Gakki Co.
Nutube is a trademark of KORG INC.
This pedal is not for sale. If you want to buy a similar pedal I recommend you Ibanez NTS Screamer.
Schematics
Some ferrites are used to filter noise at the input and output. +9VDC power voltage is also filtered by means of an EMI filter Murata NFM3DPC223R.
Op-Amps +4.5V mid voltage is generated by a LM4041 voltage reference.
Grid DC bias voltage is generated from +5V DC-DC output via a 4K7 resistor in series with a 10K trimmer. The trimmer midpoint is filtered with 10µF capacitor and connected to the grid via 33K resistor as recommended by manufacturer.
An MMBT5089 NPN transistor buffer is used between the two triode sections.
NPN buffers are also connected at the input and the output of the pedal.
An Op-Amp buffer is used at the output of the second triode section, the buffer output is connected to the 100K Mix linear potentiometer.
NuTube triodes have 500K linear trimmers on anode loads connected to +9VDC.
+5VDC is connected via 240R series resistor and filtered with 1µF capacitors to provide the required filament voltage to triodes.
R8 and R38 pull-down resistors are required to avoid popping when engaging or disengaging the effect via true-bypass 3PDT footswitch.
S1 is the switch that allows disconnecting the clipping diodes. BAV199 are dual diodes in a single SOT23 package. R14 shorts one of the diodes to provide asymmetrical clipping.
R13 can be removed to disconnect C8 220nF capacitor and disable bass-boost mod.
The output of the mix potentiometer is connected to the tone section via an Op-Amp buffer.
Volume potentiometer is a 100K audio/log taper.
Op-Amps +4.5V mid voltage is generated by a LM4041 voltage reference.
Grid DC bias voltage is generated from +5V DC-DC output via a 4K7 resistor in series with a 10K trimmer. The trimmer midpoint is filtered with 10µF capacitor and connected to the grid via 33K resistor as recommended by manufacturer.
An MMBT5089 NPN transistor buffer is used between the two triode sections.
NPN buffers are also connected at the input and the output of the pedal.
An Op-Amp buffer is used at the output of the second triode section, the buffer output is connected to the 100K Mix linear potentiometer.
NuTube triodes have 500K linear trimmers on anode loads connected to +9VDC.
+5VDC is connected via 240R series resistor and filtered with 1µF capacitors to provide the required filament voltage to triodes.
R8 and R38 pull-down resistors are required to avoid popping when engaging or disengaging the effect via true-bypass 3PDT footswitch.
S1 is the switch that allows disconnecting the clipping diodes. BAV199 are dual diodes in a single SOT23 package. R14 shorts one of the diodes to provide asymmetrical clipping.
R13 can be removed to disconnect C8 220nF capacitor and disable bass-boost mod.
The output of the mix potentiometer is connected to the tone section via an Op-Amp buffer.
Volume potentiometer is a 100K audio/log taper.
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| NuTube Screamer Schematics, page 1 |
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| NuTube Screamer Schematics, page 2. Grid bias voltage +5V DC-DC converter |
Bill of Materials
| Part Number | Mfg Name | Description | Qty | Reference | Value |
| CRCW06030000ZSTB | Vishay | Thick Film Resistors - SMD 0603 1/10watt ZEROohm Jumper | 2 | R13, R14 | 0R |
| ERJ-3EKF1001V | Panasonic | Thick Film Resistors - SMD 0603 1Kohms 1% Tol | 7 | R5, R9, R16, R23, R25, R27, R33 | 1K |
| CR0603-FX-1004ELF | Bourns | Thick Film Resistors - SMD 0603 1M 1% 1/10W | 7 | R3, R7, R8, R11, R24, R26, R31 | 1M |
| C1608X7R1V105K080AE | TDK | CAP CER 1UF 35V 10% X7R 0603 | 8 | C3, C4, C5, C6, C7, C18, C19, C23 | 1u |
| RC0603FR-073K3L | Yageo | Thick Film Resistors - SMD 0603 3.3kohms 1% Tol | 1 | R28 | 3.3k |
| ERJ-3EKF4701V | Panasonic | Thick Film Resistors - SMD 0603 4.7Kohms 1% Tol | 1 | R15 | 4.7k |
| C2012X5R1E475K125AB | TDK | CAP CER 4.7uF 25volts X5R 10% 0805 | 2 | C21, C31 | 4.7u |
| ERJ-3EKF4701V | Panasonic | Thick Film Resistors - SMD 0603 4.7Kohms 1% Tol | 1 | R35 | 4k7 |
| CR0603-FX-1002HLF | Bourns | Thick Film Resistors - SMD 0603 10KOHM 1/10WATT 1% | 6 | R1, R2, R10, R12, R22, R32 | 10k |
| GRM21BR6YA106KE43L | Murata | CAP CER 10UF 35V X5R 0805 | 15 | C1, C2, C10, C12, C13, C14, C15, C16, C17, C20, C24, C25, C26, C30, C33 | 10u |
| SRN4018-100M | Bourns | FIXED IND 10UH 1.3A 180 MOHM SMD | 1 | L1 | 10u |
| C2012X5R1V226M125AC | TDK | CAP CER 22UF 35V X5R 0805 | 1 | C32 | 22u |
| CR0603-FX-3302ELF | Bourns | Thick Film Resistors - SMD 0603 33K ohm 1% | 2 | R17, R18 | 33k |
| 06035D473MAT2A | AVX | CAP CER 0.047UF 50V X5R 0603 | 2 | C9, C29 | 47n |
| GCM1885C2A470JA16D | Murata | CAP CER 47PF 100V C0G/NP0 0603 | 1 | C11 | 47p |
| ERJ-3EKF5102V | Panasonic | Thick Film Resistors - SMD 0603 51Kohms 1% Tol | 1 | R19 | 51k |
| RC0603FR-0768KL | Yageo | Thick Film Resistors - SMD 0603 68kohms 1% Tol | 1 | R34 | 68k |
| ERJ-3EKF8202V | Panasonic | RES SMD 82K OHM 1% 1/10W 0603 | 1 | R41 | 82k |
| RC0603FR-07100RL | Yageo | RES SMD 100 OHM 1% 1/10W 0603 | 1 | R29 | 100 |
| ERJ-3EKF1003V | Panasonic | RES SMD 100K OHM 1% 1/10W 0603 | 2 | R6, R40 | 100k |
| EEE-1VA101XP | Panasonic | CAP ALUM 100UF 20% 35V SMD | 1 | C22 | 100u |
| RC0603FR-07180KL | Yageo | Thick Film Resistors - SMD 0603 180K 1% 1/10W | 1 | R36 | 180k |
| ERJ-PA3F2200V | Panasonic | RES SMD 220 OHM 1% 1/4W 0603 | 2 | R30, R37 | 220 |
| GRM188R61H224KAC4D | Murata | CAP CER 0.22UF 50V X5R 0603 | 3 | C8, C27, C28 | 220n |
| ERJ-3EKF2400V | Panasonic | RES SMD 240 OHM 1% 1/10W 0603 | 2 | R20, R21 | 240 |
| CR0603-FX-4303ELF | Bourns | Thick Film Resistors - SMD 0603 430K ohm 1% | 1 | R39 | 430k |
| CR0603-FX-5103ELF | Bourns | Thick Film Resistors - SMD 0603 510kohms 1% Tol | 1 | R4 | 510k |
| PTV09A-4020S-A104 | Bourns | Potentiometers 9mm 100Kohms Audio | 1 | VOL | A100K |
| PTV09A-4020F-B502 | Bourns | Potentiometers 9mm 5Kohms Linear | 1 | TONE | B5K |
| 3314G-2-103E | Bourns | TRIMMER 10K OHM 0.25W SMD | 1 | RV1 | B10k |
| PTV09A-4020S-B104 | Bourns | Potentiometers 9mm 100Kohms Linear | 1 | MIX | B100K |
| PTV09A-4020S-B504 | Bourns | Potentiometers 9mm 500Kohms Linear | 1 | GAIN | B500K |
| 3314G-1-504E | Bourns | TRIMMER 500K OHM 0.25W SMD | 2 | VR1, VR2 | B500k |
| BAV199235 | NXP | Rectifiers DIODE LOW LEAKAGE | 2 | D1, D2 | BAV199 |
| BLM31PG121SN1L | Murata | EMI Filter Beads Chips & Arrays 1206 120 OHM | 2 | FB1, FB2 | BLM31PG121SN1L |
| PJ-202A | CUI | CONN POWER JACK 2.1MM PCB | 1 | J2 | DCJ0202 |
| SSL-LX5093GD | Lumex | LED GRN DIFF 5MM ROUND T/H | 1 | LED1 | GREEN |
| NMJ4HCD2 | REAN | Phone Connectors 2C MONO 2-SPST NC | 1 | J1 | INPUT |
| LM4041CIDBZR | Texas Instruments | Voltage References Adjustable Precision Mcrpwr Shunt .5% | 1 | U4 | LM4041CIDBZ |
| LME49723MA/NOPB | Texas Instruments | Audio Amplifiers Dual Audio Op Amp | 2 | U1, U3 | LME49723 |
| MBR0520LT1G | ON Semiconductor | Schottky Diodes & Rectifiers 0.5A 20V | 1 | D3 | MBR0520LT1G |
| MMBT5089 | Fairchild Semiconductor | Transistors Bipolar - BJT NPN Transistor General Purpose | 3 | T1, T2, T3 | MMBT5089 |
| NFM3DPC223R1H3L | Murata | EMI/RFI Suppressors & Ferrites 0.022uF 50V 2A' | 1 | CF1 | NFM3DC |
| 831-87-032-10-001101 | APEM Inc. | Conn SIP Socket Strip SKT 32 POS 2mm Solder ST Thru-Hole | 1 | U2 | NUTUBE 6P1 |
| NMJ4HCD2 | REAN | Phone Connectors 2C MONO 2-SPST NC | 1 | J3 | OUTPUT |
| TPS62175DQCR | Texas Instruments | IC REG BUCK BST ADJ 0.5A 10WSON | 1 | U5 | TPS62175DQCR |
| MHS122K | APEM Inc. | SWITCH SLIDE SPDT 300MA 30V | 1 | S1 | clip |
PCB Layout
Top side
This is where all SMD components are mounted
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| NuTube Screamer PCB layout Top side (components) |
Bottom side
This is where all the connectors and through-hole components are mounted: DC jack, input/output jacks, switch, potentiometers, LED and battery clipping contact for GND contact with enclosure
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| NuTube Screamer PCB layout Bottom side (connectors) |
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| NuTube Screamer PCB and 1590B enclosure dimensions |
3D assembly
Eagle layout can be imported into FreeCAD 3D to create a 3D assembly image that allows placing the different holes in the assembly and checking proper mechanical assembly.
LED had to actually be moved because it interfered with tone pot.
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| NuTube Screamer 3D assembly drawing |
Could this also operate from +18v, instead of +9v?
ReplyDeleteThanks, Don
Yes, it could perfectly work at +18V, I have made simulations and you would have around 10dB of more gain.
DeleteAny suggestions or method, on setting the 3 trimmers, for the correct voltages, for grid bias and anodes ? Thanks, Don
DeleteYou can find the gain sweet spot by injecting a 1kHz sine wave at the input and tuning the trimmers until you get maximum output at the triodes anode outputs.
DeleteThis comment has been removed by the author.
ReplyDeleteFind Frequency response simulations at +9V and +18V at the end of this post, i just updated:
ReplyDeletehttps://rezzonics.blogspot.com/2018/05/nutube-screamer-spice-simulations.html
nice
ReplyDeleteThis comment has been removed by the author.
ReplyDelete