SKU: 9638951494

RED-25 Discrete Opamp

Sale price$22.50 Regular price$25.00
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Ships within 48 hours · Estimated delivery Jul 26 - Jul 31

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Description

RED-25 Discrete OpampThis kit contains all components necessary to build a RED 25 opamp. This is without a doubt the simplest discrete opamp kit available on the market today. All the heavy lifting is done for you, courtesy of the pre mounted SMT components. The RED 25 is Whistle Rock Audio's version of the sought after Huntington era AP2520 from API. Although a mostly SMT discrete opamp may seem unorthodox, you can be assured that all the components in the RED 25 have

This kit contains all components necessary to build a RED-25 opamp. This is without a doubt the simplest discrete opamp kit available on the market today. All the heavy lifting is done for you, courtesy of the pre-mounted SMT components.

The RED-25 is Whistle Rock Audio's version of the sought-after Huntington era AP2520 from API.

Although a mostly SMT discrete opamp may seem unorthodox, you can be assured that all the components in the RED-25 have been carefully selected with a no-compromise approach. Throughout the prototyping stage, no less than three different manufacturers of equivalent SMT transistors were evaluated. It goes without saying that only the very best were chosen for the RED-25. In fact, performance measurements of the opamp show that the RED-25 is on par with its through-hole counterpart.

All surface-mount resistors are Susumu thin-film resistors and all capacitors are Murata C0G/NP0 types for the lowest noise and distortion achievable.

The RED-25 sounds large and impressive. The low-end alone is worth making it a part of your tone arsenal.

FEATURES:

  • Supply voltage: +/-12 to +/-18V
  • Matched input transistors
  • Quiescent current draw: +/-30mA @ +/-16V
  • Dimensions (LxW): 1.1"x1.1"
  • Height: 0.95" from the tip of pins to top of output transistors / 0.625 from lowest solder joint to top of output transistors
  • Gold finished pins
  • Standard 990 / 2520 footprint
  • High current output
  • Carefully selected quality components throughout
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    Shipping Notes
    • Free Standard Shipping on $100+ Orders to the USA.
    • Except Preorder products are shipped in 48 hours.
    • Delivery to the USA:
    1. Standard Shipping : 3-10 business days
    • If time is of the essence, please consider selecting expedited delivery for faster service.
    Exchange/Return Notes
    • We offer a 30-day return/exchange service after receiving.
    • Final sale items are not eligible for returns or exchanges.
    • To process your return/exchange, please contact us at [email protected]
    • Please click here for more details>>> Return & Exchange Policy
    SKU: 9638951494

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    4.4 ★★★★★
    Based on 24 reviews
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    Verified Purchase
    Jerry W. Eastman
    Fort Morgan, US
    ★★★★★ 4
    Hard to set day/date.
    Color: A-Black
    Watch very professional looking and appears to be well made. Everything about this watch is what I have been looking for at a reasonable price. The only issue I have is how to set the watches features, time, date, and day. The instructions are very clear and well written, to a point. That point being the instructions say to move the "crystal" to the first notch, to adjust the day/date, and the second notch for to set the time. What the instructions fail to mention is the day/date adjustment must be turned a full 24 hours to the next day or date settlings. Also, trying to hit just the second notch is almost impossible as the is no distinct way of knowing if you are in it or not,
    WAS THIS REVIEW HELPFUL?YesReportShare
    Reviewed in the United States on March 30, 2026
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    Verified Purchase
    1Defender
    Charlottesville, US
    ★★★★★ 5
    Big face, easy to read.
    Color: A-Green Luminous
    Great watch ! Large face and hands makes it easy to read, Backface glows in dark if enough light is exposed to it. Showered a few times, no problem. Will hit the waves later this week. Update on that later. Very happy with purchase and seller. Can recommend.
    WAS THIS REVIEW HELPFUL?YesReportShare
    Reviewed in the United States on June 1, 2026
    J
    Verified Purchase
    J655
    Chelsea, US
    ★★★★★ 5
    Good price
    Color: A-Green Luminous
    I bought a return. It was 5 bucks cheaper. It looks nice and wears well. I like the color and material. I did have a little issue with setting the date. The day is in English and Chinese. That's a first, lol. It's usually in English and Spanish. It would be a nice gift for a youngster to learn military time.
    WAS THIS REVIEW HELPFUL?YesReportShare
    Reviewed in the United States on May 9, 2026
    J
    Verified Purchase
    Jennifer
    West Palm Beach, US
    ★★★★★ 3
    Broke within first 3 month
    Color: B-Green 2
    I wore it for work due to no clock and not being able to look at phone on the clock. Instead of relying on managers to tell me the time and so on I bought this. Was quite reliable until I dropped it a few times then one day I could only tell time through the minute hand. Had to replace it with a digital because I do not trust a mechanical one at the moment due to this. Also the glow barely worked, it'd glow but not bright enough to tell time and not for long. I'd say I guess you get what you pay for although it should withstand dropped better internally. Durability sucks and comfort was there.
    WAS THIS REVIEW HELPFUL?YesReportShare
    Reviewed in the United States on September 8, 2024
    J
    Verified Purchase
    J. Vuocolo
    Bozeman, US
    ★★★★★ 2
    Nice looking, but Will Not Keep Time!
    Color: C-Black Luminous 2
    This is my second watch from this company. This was a different style! The first one ran perfect for 3 years! So I brought another one. This one, out of the box was slow. I changed the battery, still, slow! I even brought a second one from them, it too is running slow.
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    Reviewed in the United States on March 31, 2026

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