A2 211 in a box!!!!

[Nick]

Well, given that Steve has posted about building a breadboard amp. I had better post some pictures on my amp in a box, just to maintain symmietry.





More of Colins quality woodwork, all the rest is my fault

[pre65]

Do i spy 6D22S "television damper diodes" ?

[Cressy Snr]

Hi Nick

Nice to see it lit up. Having seen the amp in the flesh, I know it is big, but it looks very clean and minimalist at the front, showing off those big triodes very effectively.

How's it sounding at the moment.

Steve

[Nick]

Do i spy 6D22S "television damper diodes" ?

Yep, extra points for Phil

It is a tad heavy, fits Pauls original definition of boatanher in that its just possible to more in on your own, but less that easy.

[simon]

It may be in a box, but it's a bigger box than average.

Out of interest what's your fatality rate like with the damper diodes?

[pre65]

I purchased 8,use 4 in the ECL82 power supply and had no fatalities (yet !)

[Nick]

Out of interest what's your fatality rate like with the damper diodes?

I got those two to use in the 300b regulated supply, so they have been ok for a year or so. I should get some spares. But no failures yet.

[Dave the bass]

Flippin' Rad! That looks "awesthum" as our merrycan friends say. Very big, very neat and very tidy (and also very-in-a-box...hurumph)

Well done Boss, <doffs cap>

DTB

EDIT. Forgot to add, I spy pictures of rooode ladeez with no clothes on in your workshop too, tch tch

[andrew Ivimey]

I managed to break 4 6DS22s and it was my fault. The sockets weren't bolted in flat on the chassis so when the pins were pushed in there was extra strain on the bases; all that thick glass getting hot and perhaps brittle but boing!!!!! four down. One out of four arrived from USA broken so that's five altogether.


Given that I am using eight now and haven't had any go down since I remedied the fault, I am beginning to think they are fine.

Nice looking amp Nick - mine are always so shabby!

Sowter metal throughout?

[Andrew]

Chuffin 'eck, very nice Nick. Where's the handles Nick? And the sign that says 2 man lift.....

[IslandPink]

Truly it is the New poor man's Ongaku

ILPS

[Lee S]

Awesome, Nick!! Nice job. What's the valve compliment? 211 obviously, with the damper diodes as a FW rectifier. What are the front end valves though?

[Nick]

6sn7 as voltage amp, el84 cathode follower to drive the 211, idles at about -55v on the grid, 950v B+, 80ma, swings about 180v P/P clips around 32w into 8R

[andrew Ivimey]

That's nice Nick, EL84 as pentode? Ongaku works pretty much the same though different valves; 6072SRPP into 5687(triode) ending as cathode follower at about -55volts on the grid of vt4c.

When I swapped the Hammond 10ks to Audionote ones I got so much more substance and welly, authority and .... well it sounds pretty good, anyway.

What do you reckon to those Sowters (are they sowters?) as outputs?

[Nick]

I am very please with the outputs, how they compare to others well I don't know, I compaired them to my AE 211 outputs and they are different, but its a hard difference to put into words, I would be hard pressed to say which is correct/better, but I think in this circuit. and the sound I was trying for the Sowters won out. Maybe I will witter more about the difference at Olwston.

Its running in nicely now, at first I was unsure, it sounded better on the board, but there are a few new bits in there, and I think they are bedding in now.

The general shape of the circuit is very similar to the Ongaku, but with more headroom, the driver rails are 500v instead of the Ongakus 200v. and the voltage gain is spread over more stages than the SRPP.

And there is a lot less silver in it that the Kondo Ongaku