Current project - Guitar / stereo amplifier

Hi all,
I wonder if any of you have seen the all valve AF amplifier project that I had envisioned (for many years), and was a target project or the recent transformers pages?

I have so little time these days, but by skipping breakfast and lunch I can get to work early, then either use the HF radio, or use the company metal workshop. I have finished calculating the transformers, choke and wound them. The chassis is drilled and all the components mounted ready for wiring. Even the PA and one triode all hooked up in each channel to test it.

(Picture link deleted - security problem with external storage server hosting the picture)

Stereo "single-ended" (6 + 6 Watt) amplifier chassis.

I bought some Russian NOS tubes: 6Н2П (ECC83) and 6П14П-ЕВ (EL84). They are absolutely fantastic and appear give the full spec. The only difference is that the 6Н2П tube heaters are 6.3V only on pins 4 and 5, NO 12.6V with a tapping on pin 9, so they are not a direct plug-in for the ECC83, but the ECC83 will work instead of the 6Н2П with only 6.3V on pind 4 & 5. The amplifier can deliver 6 Watts RMS per channel, although the anode current and G2 current is a little high. HT is about 340V DC for the final stage and 210V DC for the triodes.

A friend at work made a custom wooden enclosure for me, including two speaker chambers. I have 6" 30W speakers of the 1980's car-stereo style. They sound beautiful and cover the range from 70Hz to about 18kHz (-3dB). I have a couple of HiFi speakers that I robbed from the city dump and they will handle 100 Watts, with a range of less than 35Hz to more than 25kHz. These will be used as external speakers.

As you can see I have used a 3-channel tone control circuit. This is because my 70 year old ears are not what they were and I thought I could use three channels to better effect to make up for that which my ears are lacking.

As you can see there is a lot of 3D printing. I can create the files 3D at work and just upload them in the evenings during my "stolen minutes". Transformers-, choke formers, capacitor holder and even the Gnd/210V/340V buss-bar under the chassis is a PCB with 3D printed supports. I even 3D printed the knobs, but they will shortly be painted black with a bit of white hookup wire sleeve down the pointer.

Finally, a Guitar pickup only gives a few mV but the computer Line output gives more like 500mV. Instead of switching I have used a resistive attenuator at the input to give me Hi and Lo input levels.

So, shall I have it labelled "Narshall"? "Lythall"? "SM0VPO"? on the speaker grille? We shall have to see.

Best regards and goodnight from Harry - SM0VPO