Hello Steph ....................CORRECT warning for the tube sockets ! Good idea to install a digital voltmeter in front........monitoring the current of the 6C33... A 10 ohm resistor in the cathode circuit will read mV in current mA..........100mV will read as 100mA... Layout is indeed very important and designing it is thoughtfull with thisamp as well as any other amp...........;;we see quite different wrong layouts in many commercial sold amplifiers today where the looks are the dominating sales item..... Use solid core wiring of substantial gauge for the filament wiring to help drain the heat away ...........and those chinese made cheap and faulty sockets must indeed be avoid. Also good idea to mount the sockets on spacers , it will help with better ventilation flow of the heat. An inrush current limiter may be usefull too ...............the use of 105°C electrolytic capacitors also . This might be a nice project for you..... but a bit of warning because it is not so for beginner newbie DIY builders ..... I am not a fan of overal NFB to obtain those fabulous distortion measurments on sinus waves etc ....but with this amplifier maybe a small amount of NFB ....adjustable / variable and with possibility to switch it off .......may be usefull to experiment for driving some loudspeakers .....and if you don't need it the better . Succes and a lot of joy building the beast ......

i enjoy seein you do things your way. i enjoy listening to you exaplin your process.

Hi, I may have a go at constructing these, but I’m going to wait until you have one up and running and a final parts list before I jump in, I’m hoping I can use Hammond’s irons from Mouser! I have a couple of tubes, and just to see the filaments glow with 6.3v, I can confirm they get HOTtttttttttt😮 Looking forward to the next vid.

Hi Steph many thanks for your comprehensive vids on diy hifi electronics... Great stuff.. I've done the mods on the Willsenton r8... 👍👍👍👍 Funny you should mention Edcor.... I'd purchased some power trannies manufactured by them from a supplier in Germany.. it was the only option as 1 I lived in France..... pass tence and 2 Edcor wouldn't supply direct to me living in Europe... Anyway I digress, the finish on one of the BLUE transformers were utter crap, bubbling and flaking up and some rust... Complained to the German suppliers and they blamed Edcor, I contacted Edcor and they blamed the German lot.... It wasn't a great experience I must say... Table tennis between two we're not to blames..... So I repainted the buggers in a metallic silver finish.... So as you can imagine it left a bad taste in my mouth... Hay Ho we live n learn................ Sometimes.. Keep up the good work Steph....

I love mirrored monoblocks. Those things are monsters! Very cool.

Give this amplifier a name Steph !........

Looking good Stephe. They sure are monsters - lovely ones

Don't cut a hole for a cheap digital meter before testing. I bought some for my 845 se bias meters (low voltage across filament resistor to ground) and they jumped all around uselessly, even with a regulated supply that is super stable. The cheap analog meters I replaced them with are both better looking and functional.

Just a little detail ................give enough ventilation holes for the underside panel....

The 6C33C amp/s is/are lookin good Stephe! I wouldn't recommend the silver coloured heat transfer paste like they use on CPU's though; just use the normal white Silicon one! If you let even ONE ATOM of that silver stuff get ANYWHERE it's not supposed to be - especially on your fingers - you're gonna have a crappy looking silver-blemished black amp chassis forever, cos the silver gets into the paint! The white silicon heatsink compound stuff just wipes off with white spirit, although you should check if the white spirit affects the powder-coating. Hey did you say a TWO HUNDRED Henry choke for the 6C33C? Not even 'just' 20 henries? You're gonna have to mount these monsters on castor wheels lol! - Or did you mean just 2 henries?

It looks good so far!

One thing about your power supply you might have already checked. The 50ohm resistor and the 220uf cap form a low-pass filter and the -3dB cutoff is at 14.46Hz. Are you comfy with that?

Good tip on Soviet vs Chinese sockets. Bad crap is all over the place nowadays, hard to discern for an untrained eye. Nice to see a cheap pentode like a 6J52P there, but beware the microphonics.

Looking forward to the finished amp. I had a pair of 6c33c sitting on my bench for a while but I never pulled the trigger on it and sold them on. Curious about how you'll manage to get the BIAS to stay in place. Seen some reviews of those amps that complained about some runaway voltages/currents.

What's your favourite amp you have made it modified?

Hey Stephe, perhaps you stressed it, but where do you get those nice looking chassis? I need one larger for my 300b... Its evolution continues and it needs more room... Thanks

I'ts easy to tame toroids inrush current, when used as the power transformer. You just put a C60 NTC resistor in series with the mains. Problem solved.

As far as I understand it, toroids are problematic for mains power duty as they saturate very easily when dc is present on the line, which with all the electronic PSUs these days, is common. You can make a dc blocker circuit to stop this. The SE O/P toroids are designed to accommodate their specified dc current without saturating. Inrush current on switch on can also be an issue, so a soft start circuit can solve that issue. So I can see why you are not keen on them.

I'm concerned that a small diameter piece of metal could be pushed in between the spacers on the valve, tube to you, by children, with possible disastrous results . Cheers Cliff.

Just turn the power transformer or the opt 90°....