he Audio Valve Nut - Trials and Tribulations of setting up An Audio Test Bench

Hi, Will from the U.K. Just a bit of my background before we start:

Electronics Technician for the past 27 years, worked for British, French, American, Japanese and Korean Electronics Companies and the Medical Industry.

While in Collage studying, a few of the lecturers were in their 60’s and were from the 40-50’s era and said Valve Amplifiers were by far the best compared to the Semiconductor Amplifiers. So, I said to myself, one day I will build a Valve Amplifier and find out. There are many good semiconductor amps about but are 5-10 times the price. I like to listen to music reasonably loud and started to notice the harsh clinical sound with semiconductor amplifiers and that were getting irritating to listen to. May be an age thing?

That day has now come to build that Valve Amplifier. I decided to start collecting equipment over the last couple of months to set up an Audio Test Bench. Started browsing over the internet for good Stereo HIFI circuits or built Valve Amplifier’s. Built Amps expensive, need a large jump in faith to go that route. May need to try out may different amplifiers, Speakers, combinations, and other equipment and match it up to get a good system. Looked at a few Chinese Amps online but hearing about quality/ warranty issues decided to look for circuits and build a proven design.

Found Blueglow Electronics online hosted by Mark, saw his KT88 Amp build and thought that will be a good place to start. Started sourcing parts and found the O/P transformers from Edcor are almost twice the price here in the UK. Found Hammond supply a suitable replacement but on further investigation they have a dip in the frequency response at about 18khz. I probably would not notice as my top end hearing is not that good anymore. If I’m going to build an Amp, I’m going to build the best I can. Then found “Skunkie”, watched all the videos and enjoyed them. Nice to see somebody who can Solder Correctly, it’s quite common to see people even in the trade who can’t Solder correctly. Keep up the Good Work with the Videos and Instructions.

Decided to buy a cheap 12W Per Channel Chinese Valve Amp just to get started so I could start testing speakers while searching for designs I could get all the parts for. Tested about 10 pairs of speakers so far, got 3 good pairs so far. 1 pair for the workshop, 1 as a spare and 1 for the living room. The others may be good with other Amps/setups but 1 or 2 were not good at all for top brands. For a cheap Chinese Amp. the sound is quite good with the right speakers, now I’m listening to the sound stage and can hear changes / variations in how the music has been mixed, live is amazing with the right recording. Quality is far better than Quantity. Oh My God , I have turned into an Audiophile.(Looks like I have always been an Audiophile but didn’t know it) .

Just purchased another Chinese Amp (so cheap, It would cost that much just for the transformers and the case alone) but this one is an EL34 Single Ended Output just to see the difference between the types of O/P’s to see which one I prefer. OOOPPSS falling further down the Audiophile Rabbit hole. Also I want to try an experiment with it, Use their components and then use quality components and see if there is a marked difference. Getting close now to completing equipment acquisition to set up the Audio Bench. Around Christmas time I will re design my current setup for a proper Audio Setup ready for some proper testing/experimenting. Bring on the Tube Rolling.

Attached are a few Trials and Tribulations on the way.

(If you want to see more I’ll do a part 2 Just let us know).

The Trials And Tribulations in a Nut Snell