It’s a sunny Saturday. It has been agreed to have a measurement of some amplifier to check their power output. Located at Bintaro, I bring my Rigol Oscilloscope and Sanwa True RMS Multitester. Both should be enough to give rough measurement of the power output (and check whether they operate at A or AB class). As a source, we use 1 kHz tone, and around 7R/120W of dummy resistor.

I forgot how to activate Vpp and Vrms of this Rigol, so we use an additional RMS meter to measure the output. But finally I remember how to activate them and that simply simplify the testing.

After the test has been completed on several amplifier, we continue the session by some listening test and I take some pictures. Enjoy it 😉

Ultimate version of MP50Di. PCB designed by local hobbyist, Mr. Didik. Complete unit below made by Mr. David.

Seriously made power bank!

Boutique part test! Mention at least 10 pcs of high end brands used here. Don’t say you are a serious DIY if you can’t mention at least 15 brands… (roughly I see at least 14 brands).

Bias measurement. Also can see whether the amp still operates at A or already move to AB.

Bias measurement in detail.

Ultimate modification of Yaqin VK-2100 hybrid amplifier. Need some magic touch on its SRPP side. Very powerful on the final stage, with around 90W of power each channel!

Seeing something unusual here? 😉

The F4-Hybrid amplifier. Massive power bank, some interesting tweaks also found here (if you can notice that).

It’s time to fire up. Three Talema toroidal transformers definitely more than enough to deliver the juice needed by the power amp.

Plugging in the tubes for the SRPP side of Yaqin VK-2100. Different tube could produce different sound.