Toshiba

2SK170-GR - N-Channel JFET Low Noise Audio | Toshiba

Name: 2SK170-GR - N-Channel JFET Low Noise Audio | Toshiba
Brand: Toshiba
Price: 0.5 USD
Availability: InStock

MPN: 2SK170-GR ✗ End of Life

In Stock Ships in 1-3 business days

[DATA_NEEDED: Drain-Source Voltage] Vdss 2.6 mA to 6.5 mA Id TO-92 (3-pin) Package

From $0.5 USD / Unit

MOQ: 1 |

Price updated: 2026-09-12

Volume Pricing

Qty	Unit Price	Extended
1	$0.72	$0.72
10	$0.65	$6.50
100	$0.58	$58.00
500	$0.53	$265.00
1,000	$0.5	$500.00

ℹ️ All prices are in USD

View Datasheet (PDF) View Alternatives

Quantity

Drop-in alternatives for 2SK170-GR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.

Quick Comparison Tool — Select alternative parts for side-by-side comparison:

2SK170-BL

✅ Drop-In

Toshiba

📦 TO-92

N-Channel JFET (Junction FET) · Silicon N-Channel Junction Type · Low Noise Audio Amplifier · 12 mA · 40 V · BL (highest Idss grade of 2SK170 family) · [DATA_NEEDED: gate-source voltage rating] · [DATA_NEEDED: Idss range for BL grade]

✓ In Stock

$2.1 / Unit

View Datasheet →

2SK117-GR

✅ Drop-In

📦 TO-92

same GR Idss grade 2.6-6.5 mA and same pinout; slightly different channel geometry/noise curve

📋 Reference alternative (not in catalog)

LSK170A

✅ Drop-In

Linear Integrated Systems

📦 TO-92

N-Channel JFET Amplifier · Single · 40 V · [DATA_NEEDED: Gate-Source Voltage] · 10 mA · 400 mW · 2.6 mA to 6.5 mA (VDS = 10 V) · Ultra-low noise (audio-grade)

✓ In Stock

$0.94 / Unit

View Datasheet →

LSK170B

✅ Drop-In

📦 TO-92

pin-for-pin 2SK170 replacement, Idss 6-12 mA vs GR 2.6-6.5 mA (about +100% bias current)

📋 Reference alternative (not in catalog)

LSK170C

✅ Drop-In

📦 TO-92

pin-for-pin 2SK170 replacement, higher Idss grade (roughly 12-20 mA) requiring bias circuit adjustment

📋 Reference alternative (not in catalog)

2SK170-GR Maximum Ratings & Electrical Characteristics

Transistor Type	N-Channel JFET (depletion mode)
Grade	GR (Idss 2.6 mA to 6.5 mA)
Idss (Zero-Gate Drain Current)	2.6 mA to 6.5 mA
Application	Low noise audio amplifier
Package	TO-92 (3-pin)
Mounting Type	Through Hole
Technology	Silicon N-Channel Junction Type
Pin Count	3
Replacement Series	LSK170 (Linear Systems)

2SK170-GR Pin Configuration

Pin 1	G (Gate) — Gate - high-impedance control terminal
Pin 2	D (Drain) — Drain - connects to positive supply side
Pin 3	S (Source) — Source - connects to ground or bias resistor

Safe Operating Area (SOA) & Thermal Characteristics

No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.

Typical Applications

2SK170-GR is suitable for 6 applications: Phono Preamplifier Input Stage, Discrete Audio Preamplifier, Condenser Microphone Buffer, Low-Noise Measurement Front Ends, Guitar Effects and Instrument Inputs, RF and Oscillator Gain Blocks (LF).

🎧

Phono Preamplifier Input Stage

The 2SK170-GR is a classic input device for moving-magnet and moving-coil phono stages, where cartridge signal levels are in the millivolt range and any input noise is amplified by the RIAA EQ network. Its N-channel JFET gate presents gigaohm-level input impedance, preventing cartridge loading and preserving high-frequency response, while the GR grade's 2.6-6.5 mA Idss allows a bias point that minimizes input-referred voltage noise without excess dissipation. Designers run the device at roughly half Idss via a self-bias source resistor and parallel multiple matched units to reduce noise by the square root of the device count. Because Toshiba discontinued the part, matched GR stock or Linear Systems LSK170A replacements are typically specified today.

Recommended

🔧

Discrete Audio Preamplifier

In discrete hi-fi and instrument preamplifiers, the 2SK170-GR serves as the first amplifying device after the volume control or input selector. The JFET's extremely low 1/f corner noise keeps the noise floor below the thermal noise of the source impedance, while its depletion-mode operation permits simple one-resistor self-bias with no gate supply. The GR grade Idss (2.6-6.5 mA) suits battery-powered preamps where standing current is limited. In differential or cascode front ends, matching Idss across the pair is essential - designers measure and bin devices to within a few percent to cancel offset and even-order distortion. The TO-92 through-hole package also makes it easy to hand-match and solder in point-to-point audio builds.

Recommended

2SK170-BL · Toshiba 2SJ74-BL · Toshiba

🎥

Condenser Microphone Buffer

Electret and externally polarized condenser capsules need a follower with near-infinite gate impedance to sense the capsule charge without discharging it, and the 2SK170-GR is a canonical choice. Configured as a source follower, the GR-grade device draws only a few milliamps, important in 48 V phantom or battery-powered microphones, while its low input capacitance minimizes capsule loading and high-frequency loss. The gate leak resistor (typically 1 gigaohm) biases the gate at DC, and a source resistor or current source sets the follower current near half of Idss. Matching is less critical than in differential stages, but Idss measurement is still recommended to set the bias point correctly per unit.

Recommended

2SK170-BL · Toshiba LSK170A · Linear Integrated Systems

🔬

Low-Noise Measurement Front Ends

Laboratory and industrial instrumentation that measures signals from high-impedance sources - pH probes, photodiodes, piezoelectric sensors - benefits from the 2SK170-GR as a source-follower or common-source buffer. The JFET's gate leakage is in the picoampere region, so it does not discharge high-impedance sensors, and its low voltage noise keeps small signals resolvable above the floor. The GR grade's modest 2.6-6.5 mA Idss suits low-power portable instruments. For precision work, bias the device in a cascode to stabilize drain voltage and reduce Miller capacitance, and shield or guard the gate node to prevent leakage paths across the PCB surface.

Recommended

LSK170A · Linear Integrated Systems 2SK170-BL · Toshiba

🎸

Guitar Effects and Instrument Inputs

High-impedance instrument inputs - guitars, piezo pickups, ribbon microphones - use JFET buffers to avoid loading the source and dulling the tone. The 2SK170-GR's gigaohm gate impedance preserves the pickup's natural resonance, and the GR grade bias current keeps battery-powered stompbox circuits economical. A simple source follower with a 1-10 megaohm gate bias resistor is the standard topology; the device's low noise ensures hiss stays below audibility at typical gain settings. The DIY audio community actively recommends 2SK117-GR as a direct replacement with the same parameters and pinout, since original 2SK170 stock is exhausted and re-marked counterfeits circulate in the surplus channel.

Recommended

2SK117-GR (Same-grade same-pinout replacement from Toshiba) 2SK170-BL · Toshiba

🌐

RF and Oscillator Gain Blocks (LF)

Below the VHF range, the 2SK170-GR also performs well as a low-noise gain device in local oscillator buffers, crystal oscillators, and IF front ends where a bipolar transistor's base current noise would be excessive. Its high transconductance for a small-signal JFET and low feedback capacitance support stable Colpitts and Pierce oscillator operation, and the GR grade current keeps crystal drive within safe limits. In receiver front ends for LF/HF bands, a cascode connection with the 2SK170-GR as the lower device minimizes Miller effect and improves reverse isolation. Designers verify the drain-source and gate voltage ratings against the Toshiba datasheet before applying supply voltages.

Recommended

2SK170-BL · Toshiba LSK170B (Active-production replacement for RF designs)

Recommended Products Summary

2SK170-BL Toshiba Used in: Phono Preamplifier Input Stage, Discrete Audio Preamplifier, Condenser Microphone Buffer, Low-Noise Measurement Front Ends, Guitar Effects and Instrument Inputs, RF and Oscillator Gain Blocks (LF) LSK170A Linear Integrated Systems Used in: Phono Preamplifier Input Stage, Condenser Microphone Buffer, Low-Noise Measurement Front Ends 2SJ74-BL Toshiba Used in: Discrete Audio Preamplifier 2SK117-GR Same-grade same-pinout replacement from Toshiba Used in: Guitar Effects and Instrument Inputs LSK170B Active-production replacement for RF designs Used in: RF and Oscillator Gain Blocks (LF)

What is the Idss of the 2SK170-GR?

The 2SK170-GR has an Idss (zero-gate-voltage drain current) of 2.6 mA to 6.5 mA, which is the GR grade bin. Toshiba grades the 2SK170 into bins such as GR and BL, where GR is the lowest-current grade and BL is 6-12 mA. Selecting the GR grade lets designers set a lower bias current, reducing power dissipation and tuning the noise-versus-current trade-off in low-noise audio input stages. Datasheet source: Toshiba 2SK170 datasheet PDF.

Is the 2SK170-GR discontinued?

Yes, the Toshiba 2SK170-GR is an end-of-life (EOL) part; the entire 2SK170 family has been discontinued by Toshiba. It remains available from surplus and remaining distributor stock, and Linear Systems explicitly markets the LSK170 series as a direct, pin-for-pin replacement for the 2SK170 in TO-92, SOT-23, and SOT-89 packages. For new designs, plan around LSK170B (6-12 mA Idss) or match GR-range units from LSK170 stock.

What is the best drop-in replacement for the 2SK170-GR?

The best drop-in replacement is the Linear Systems LSK170 series in the TO-92 package - Linear Systems documents it as a direct, pin-for-pin replacement for the Toshiba 2SK170. For a same-brand option, the Toshiba 2SK117-GR has the same GR Idss range (2.6-6.5 mA) and the same pinout, making it a direct replacement from the same manufacturer. Verify Idss grade and match devices before substitution in matched-pair circuits.

What is the difference between 2SK170-GR and 2SK170-BL?

The difference is the Idss grade bin only: the GR grade has Idss of 2.6 mA to 6.5 mA, while the BL grade has Idss of 6 mA to 12 mA. Both share the same die, package (TO-92), pinout, and low-noise characteristics. Choose GR for lower bias current and lower power dissipation; choose BL when you need higher transconductance and headroom, at the cost of roughly double the standing current.

What is the pinout of the 2SK170-GR in TO-92?

The 2SK170-GR in the 3-pin TO-92 package uses pin 1 = Gate, pin 2 = Drain, and pin 3 = Source (flat face facing you, leads down, numbered left to right). The gate is the high-impedance control terminal, the drain connects to the positive supply side, and the source to ground or the bias resistor. Always confirm against the Toshiba datasheet pin diagram before PCB assembly, since TO-92 pinouts vary across manufacturers.

Where can I buy the 2SK170-GR and what does it cost?

The 2SK170-GR is available from surplus and remaining-stock distributors. Reference pricing is approximately $0.50 per unit at 1000-piece volume, with unit quantities around $0.50-$0.70 (as of 2026-09-13; one listed reference price is $0.498 from AiPCBA). Because the part is EOL, stock varies by seller, and counterfeit re-marked devices are a known risk - buy from reputable distributors and verify Idss on receipt.

2SK170-GR vs LSK170B - which is better for a phono preamp?

For a phono preamp, both are excellent; the LSK170B is more practical today. The 2SK170-GR offers the original 2.6-6.5 mA Idss bin and the classic ultra-low noise signature, but is discontinued and subject to stock risk. The LSK170B (Linear Systems, 6-12 mA Idss) is a documented pin-for-pin replacement with equal or better noise, active production, and RoHS-compliant packaging. Use GR parts for restoring original designs; use LSK170B for new builds and long-term availability.

Is the Toshiba 2SK117-GR a direct replacement for the 2SK170-GR?

Yes, the Toshiba 2SK117-GR is widely regarded as a direct replacement for the 2SK170-GR: it shares the same GR Idss grade (2.6-6.5 mA), the same N-channel JFET silicon-junction construction, and the same TO-92 pinout. Audio design forums document it as having the same parameters and pinout. Check the transfer characteristic and noise figure in your specific bias condition, and note that the 2SK117 is also a discontinued Toshiba part, so both may need LSK-series substitution long term.

Can the 2SK170-GR be used as an input buffer for condenser microphones?

Yes, the 2SK170-GR is well suited to condenser microphone buffer stages because its JFET gate provides extremely high input impedance, which is required to sense the electret/condenser capsule without loading it. The GR grade's 2.6-6.5 mA Idss allows a bias point that balances noise against battery drain in powered microphones. A self-bias source resistor and a high-value gate resistor set the operating point; device matching matters in differential or parallel configurations for lowest noise.

What is the Linear Systems equivalent for the 2SK170-GR?

The Linear Systems equivalent is the LSK170 series, which the manufacturer explicitly documents as a direct replacement for the Toshiba 2SK170. The closest match to the GR grade (2.6-6.5 mA Idss) is the lower-current LSK170 grade - LSK170A - available in the same TO-92 package as well as SOT-23 and SOT-89. LSK170B covers 6-12 mA, matching the BL grade. Contact Linear Systems for tighter noise and Idss sorting options, as the company offers factory selection.

Why is the 2SK170 considered low noise, and what is its noise figure?

The 2SK170 is considered low noise because it is an N-channel JFET with no gate oxide: conduction occurs in the bulk silicon channel, avoiding the 1/f surface noise typical of MOSFETs, and the wide channel geometry yields very low input-referred voltage noise at audio frequencies. The precise noise figure value is not stated in the summary data available here - consult the Toshiba datasheet noise curves - but the part was specifically marketed by Toshiba for low-noise audio amplifier applications.

How should I bias a 2SK170-GR in an audio input stage?

Bias the 2SK170-GR as a depletion-mode JFET: source-to-ground through a source resistor so the gate sits at 0 V and Vgs becomes negative by the resistor drop. Target roughly half of Idss (about 1.3-3.3 mA for the GR grade) for a good linearity and margin trade-off. Measure each device's actual Idss, since GR units range from 2.6 mA to 6.5 mA, and match pairs for differential inputs to minimize offset and second-harmonic distortion.

What are the key specifications of the 2SK170-GR that engineers should know?

The 2SK170-GR is a Toshiba N-channel silicon junction JFET for low-noise audio, in a 3-pin TO-92 package. Key specifications: GR grade Idss of 2.6 mA to 6.5 mA, depletion-mode operation (conducts at Vgs = 0), high gate input impedance, and very low input-referred noise marketed specifically for audio amplifier inputs. It is end-of-life, with the Linear Systems LSK170 series documented as the pin-for-pin replacement. Verify remaining parameters (voltage ratings, Yfs, capacitance) against the Toshiba datasheet.

What is the lead time and availability for the 2SK170-GR?

Because the 2SK170-GR is discontinued by Toshiba, availability depends entirely on remaining distributor and broker stock, and lead time is not guaranteed or manufacturer-quoted. Some distributors show stock that ships immediately, while brokered quantities may take days to weeks with quality risk. For production programs, qualify the Linear Systems LSK170 series, which is in active production, or the equivalent-grade LSK170A, to remove supply risk from your bill of materials.

Is the 2SK170-GR RoHS compliant and lead-free?

Compliance status for the 2SK170-GR is not confirmed in the data retrieved for this page: the original Toshiba production run predates uniform RoHS labeling, and TO-92 through-hole parts of that era may have tinned (lead-containing) leads. Treat RoHS and lead-free status as unknown and verify with the specific seller's certificate of conformity before specifying it in a compliant product. The LSK170 replacement series from Linear Systems is documented as available in RoHS-compliant packaging.

Engineering reference data for 2SK170-GR — comparison, design guidance, and compliance information.

Selection Guide

Choose the 2SK170-GR when you are restoring or servicing original Toshiba-era audio equipment and need the authentic 2.6-6.5 mA GR grade, accepting EOL stock risk and the need to verify authenticity. Choose the 2SK117-GR for the same grade and pinout when 2SK170-GR stock is unavailable, with the caveat that it is also discontinued. For all new designs, choose the Linear Systems LSK170 series: the LSK170A targets the GR-like lower Idss range, while the LSK170B replaces the BL grade at 6-12 mA and is the default recommendation for new phono stages and preamps requiring higher transconductance. The LSK170C suits high-current, high-headroom stages. All five devices share the TO-92 pinout (G-D-S), so PCB footprints and layouts transfer directly across the family.

Comparison with Alternatives

Parameter	This Product	2SK170-BL	2SK117-GR	LSK170A	LSK170B
Package	TO-92 (3-pin)	TO-92 - same	TO-92 - same	TO-92 - same	TO-92 - same
Brand	Toshiba	Toshiba	Toshiba	Linear Systems	Linear Systems
Idss Grade	GR (2.6-6.5 mA)	BL (6-12 mA)	GR (2.6-6.5 mA)	Grade A (closest to GR range)	Grade B (6-12 mA)
Transistor Type	N-Channel JFET	N-Channel JFET	N-Channel JFET	N-Channel JFET	N-Channel JFET
Pinout	1=G, 2=D, 3=S (TO-92)	Identical	Identical	Pin-for-pin replacement (documented)	Pin-for-pin replacement (documented)
Lifecycle Status	EOL (discontinued by Toshiba)	EOL	EOL	Active production	Active production
Primary Application	Low noise audio amplifier	Low noise audio amplifier	Low noise audio amplifier	Ultra low noise audio/acoustic	Ultra low noise audio/acoustic
Approx. Unit Price (qty 1, as of 2026-09-13)	$0.72	[DATA_NEEDED]	[DATA_NEEDED]	[DATA_NEEDED]	[DATA_NEEDED]

Key Differentiators

Lowest-current grade in the 2SK170 family (vs 2SK170-BL)
Active-production equivalent available (vs 2SK117-GR)
Honest trade-off: higher-current grades give more transconductance (vs LSK170B)

Design Notes

The GR grade spans 2.6 mA to 6.5 mA of Idss - a 2.5:1 spread. Never assume a nominal value: measure Idss of each unit at Vds = 10 V, Vgs = 0 before biasing. In differential input pairs, match devices within about 5% of Idss to cancel offset and even-order distortion. Counterfeit and re-marked 2SK170 parts circulate widely since discontinuation; buying from reputable distributors and verifying Idss on receipt is essential.

Estimated: bias the GR-grade device at roughly half its measured Idss (about 1.3-3.3 mA). With a 15 V supply and a drain load of, say, 4.7 kilohm, dissipation is a few tens of milliwatts - far below any thermal concern in TO-92. The real constraint is the drain-gate voltage rating: consult the Toshiba datasheet for maximum ratings and keep the drain-gate bias well inside the limit, especially in cascode or oscillator circuits where swings exceed the quiescent point.

For through-hole TO-92 audio circuits, keep the gate trace short and guarded: a high-value (1-100 megaohm) gate leak resistor plus PCB surface leakage can dominate noise and offset. Ring the gate node with a guard ring driven at source potential, clean flux thoroughly, and use glass-epoxy PCBs. In follower configurations, place the source resistor close to pin 3 to minimize loop area. This mirrors the layout practice shown in Toshiba application examples for the 2SK170.

Compliance Information

RoHS

Unknown

REACH

Unknown

AEC-Q100

Not Applicable

Lead Free

Unknown

Halogen Free

Unknown

Conflict Minerals

Unknown

Original 2SK170 production predates uniform RoHS labeling; verify certificate of conformity with the specific seller. The LSK170 replacement series is documented as available in RoHS-compliant packaging.

Data verified on: 2026-09-13 — data verified and curated by XAIPART's component engineering team

Sources: Manufacturer_Datasheet, Distributor, Manufacturer_Product_Page, Manufacturer_Datasheet, Octopart, Distributor, Distributor

Related Components & Terms

Toshiba 2SK170-GR 2SK170-BL 2SK117-GR LSK170A LSK170B Linear Systems 2SJ74-BL JFET junction field-effect transistor N-channel depletion mode Idss TO-92 package low noise audio amplifier phono preamplifier transconductance (Yfs) gate input impedance EOL (end of life)