The OPA2134 with JFET's is a high-end DIY stereo amplifier for dynamic headphones. It was designed with an emphasis on maintaining simplicity in the signal path, and utilizes an all-discrete, fully-complementary topology featuring a JFET input stage, current-mirror VAS (voltage gain stage), Sziklai complementary feedback pair (CFP) output stage, and no global negative feedback. 

It is also ideal as a pre-amplifier line stage. Just add multiple inputs and a selector switch. Its low output impedance and high output current capability allows it to drive a power amplifier over long interconnect cables without signal degradation.

Designed to be a compact AC-powered desktop unit, it provides high performance with relatively minimal complexity for an all-discrete design. In conjunction with an off-the-shelf enclosure solution, the amplifier is simple and inexpensive to build. 

Based on the Kumisa III by Benny Jørgensen, it adds several significant enhancements by Alex Cavalli. Alex and AMB teamed up and performed SPICE simulations and fine-tuning, as well as printed circuit board layout. The project was conducted with community participation, in an open-source manner , and the result is an exceptional amplifier you see here. 

Amplifier is designed to be easy to build, but is not recommended as a first-time project for the beginner.

pcb is FR4 1.6mm 2oz Blue  (HASL)

Shipping Address &

Combined Shipping

 We ship to confirmed addresses. If there is a different address that you would like to have the item shipped to, please let us know.  When you buy multiple items, we will do combine shipment and. If send us an email or message, we will respond in 24 hours.

Shipping Time

We ship the item next day after the payment has been received. If there is a delay in the shipment, we will notify the buyer immediately. We use Regular air mail or Priority Mail depending on the item purchased.

Delivery Time

Delivery times are different depending on the shipment method. Priority mail takes approximately 2-3 days . The delivery time is up to the post office.

Returns/Exchange

We accept exchange/returns within 14 days of customer receiving the item. Buyers pay the return shipping. Item must be sent back in original condition for exchange or return. For returns on products that are unwanted, there is a 20% restocking fee for the item. Please message us or email us in regards to returns/exchanges.

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