211 or 845 project

[h00hbt]

Anyone know of a good 211 or 845 stereo layout? Im searching for a new project to start after the summer.

Cheers

[Bas Horneman]

Hi h00hbt,

Saw your post over at the asylum. Do you have 845's or 211's? It seems to me this is one of the biggest obstacles to building an amp with either of them.

Cheers,
Bas

[kevinkr]

The GM70 is another choice to consider, widely available and pretty inexpensive. I'm currently working on an IT coupled GM70 design after abandoning a design based on the 211 which at the time was getting hard to find new.. One set of vintage VT4C in my possession did not give me sufficient confidence.. They're a bit easier to get now, but cost a lot more than they used to.

[h00hbt]

Hello Bas & kevinkr

Well I havn´t got the actual tubes yet but I was thinking of going for transmitter like tubes. I have a set amp based on GM70 already so Im happy in that matter. Yes, 211 are somewhat scarse so maybe 845´s are a better choice. I could go PP but I hear this wears the tubes more than SE so I think I will settle for SE. Mercury vapor rectifiers would be great in the PS.

So if you know of a schematic I would be grateful

Cheers

[kevinkr]

Originally Posted by h00hbt

Hello Bas & kevinkr

Well I havn´t got the actual tubes yet but I was thinking of going for transmitter like tubes. I have a set amp based on GM70 already so Im happy in that matter. Yes, 211 are somewhat scarse so maybe 845´s are a better choice. I could go PP but I hear this wears the tubes more than SE so I think I will settle for SE. Mercury vapor rectifiers would be great in the PS.

So if you know of a schematic I would be grateful

Cheers

PP operation does not in any sense negatively impact tube life, SE operation actually is harder on a given output tube because you generally run class A at very high currents in order to get reasonable linearity. PP amps can be run at much lower quiescent currents and can produce > 4 X the power of a single SE output tube operating at similar voltages and currents.

I personally prefer SE amplifier designs sonically speaking, however to say that PP configuration is harder on a tube than SE is just not true.

Not a big fan of MV rectifiers, see this thread for why: Looking for a 866a powersupply schematic

[h00hbt]

Ok, this is good news about PP and tube life....read something somewhere about this puting stress on the tubes. MV rectifiers are a bit dodgy but I like them, this is not a must have. I found a schematic, se link, -what do you think of it?How Hashimoto Sounds

Cheers

[tinitus]

Originally Posted by h00hbt

Hello Bas & kevinkr

I have a set amp based on GM70 already so Im happy in that matter. Yes, 211 are somewhat scarse so maybe 845´s are a better choice.
Cheers

exstremely nice looking

845 Trioden-Monobloecke von Robert Troesch

[tinitus]

another amp worth a look

6C33C-B SE Verstaerker von Juergen Buschmann

[djn]

Another amp to look at is the Tim Mellow 25wpc 6C33C OTL. I tried to attache the write up but it is too big. Email me at djnagle@comcast.net if you want a copy. Cheers.

[wrenchone]

GM70s or 813s are both easier to find (and cheaper) than either the 211 or 845. From what I hear (especially in the case of the 813) easier to drive, too. I have to admit that the 211 and 845 have that retro "Flash Gordon" look, but I'm not willing to pay a big, fat premium just for that.