Search found 4206 matches

by Andrew
Fri Sep 07, 2007 7:43 am
Forum: Everyones Projects
Topic: 6AS7 SE OTL
Replies: 24
Views: 23364

The ouput valves are effectively Cathode Followers right? So unless I'm missing something, a constant current source would do the job, yes, and keep the blighters in check, to boot. But you might be better of with something like the IXYS IXCP10M45S, I think you might find it easier to dial in the re...
by Andrew
Thu Sep 06, 2007 8:39 pm
Forum: Beginners
Topic: Aikido power supply
Replies: 29
Views: 23913

Down side of the SS reg, is I don't know enough to build one thats good for 150ma @ 450v. I am sure it can be done though. But without that I can't do a direct comparison. I've managed to get as far as 100mA @ ~220v so, yes, I reckon Nick's right, it's possible, my issue has been getting them quiet...
by Andrew
Thu Sep 06, 2007 8:29 pm
Forum: Everyones Projects
Topic: 6AS7 SE OTL
Replies: 24
Views: 23364

That's some bias/cathode arrangement! I assume all the valves have to be balanced to stop one or t'other hogging all the current?
by Andrew
Thu Sep 06, 2007 8:08 am
Forum: Beginners
Topic: Aikido power supply
Replies: 29
Views: 23913

Well, its only my bias, but the idea of increasing the source impedance of a power supply by adding resistance to burn voltage seems a mistake. I would agree, unless its a lash up to try something out, and then a variac seems a better solution for prototyping. I would also avoid multiple LC combo's...
by Andrew
Tue Sep 04, 2007 6:27 pm
Forum: Beginners
Topic: Variac !!!
Replies: 6
Views: 8133

2A is about 500watts at mains voltages, so at 500v you should be able to draw 1 amp, or 500mA at 1000v or at 250v 4 amps and so on.

I don't think anyone but perhaps Paul, Nick and Darren with their SE behemoths needs that much HT at that kinda current.

cheers,

-- Andrew
by Andrew
Tue Sep 04, 2007 8:53 am
Forum: Assorted Stuff
Topic: Rapid Valve Sockets
Replies: 7
Views: 7321

Thanks, that's what I thought too.

cheers,

--Andrew
by Andrew
Tue Sep 04, 2007 7:56 am
Forum: Everyones Projects
Topic: DTBs 6B4G
Replies: 361
Views: 220052

Oh no Nick's got the Were Wabbit...caged in......quick someone get the Holy Hand Grenade....
by Andrew
Tue Sep 04, 2007 7:14 am
Forum: Everyones Projects
Topic: D3a linestage
Replies: 24
Views: 16269

Pretty impressive, how does it sonically compare to the old Cathode Follower?

cheers,

-- Andrew
by Andrew
Mon Sep 03, 2007 11:08 am
Forum: Everyones Projects
Topic: D3a linestage
Replies: 24
Views: 16269

When I looked at this circuit, I thought nah it will never work, but then I looked up the Miller cap of the D3A and then added a bit for safety and got about 180kHz or something with a quick/rough calculation.

Now, that suprised me, there you go I thought, always worth thinking about these things.
by Andrew
Mon Sep 03, 2007 9:57 am
Forum: Everyones Projects
Topic: D3a linestage
Replies: 24
Views: 16269

Hi Nick, What's the freq limit of the sig gen you have? It would be really interesting to see where this circuit starts to roll off in real life and if it matches the predicted 3db point of 100k into Miller Cap of D3a triode. Theory says it should be well out of audible range, of course. cheers, -- ...
by Andrew
Mon Sep 03, 2007 7:52 am
Forum: Assorted Stuff
Topic: Rapid Valve Sockets
Replies: 7
Views: 7321

Hi Andrew i am using the rapids B9A CERAMIC CHASSIS GOLD PLATED and they seem fine pin seem to be tight good fit hope this helps Colin Hi Colin, Just to check this is the normal pitch, not the small pitch; there's nothing worse than an order turning up and you got the wrong bits. thanks, -- Andrew
by Andrew
Sun Sep 02, 2007 8:12 pm
Forum: Everyones Projects
Topic: DTBs 6B4G
Replies: 361
Views: 220052

No, well certainly not as silly as the idea I had last night....I had this odd thought for PSU for an amp I've been scheming up, a MC no step up phono amp. The PSU will be a buggar, so I thought what about a series stack of 12v sealed lead acid batteries, paralleling them up to charge them dead quie...
by Andrew
Sun Sep 02, 2007 6:33 pm
Forum: Assorted Stuff
Topic: Audio Jumble, Kent.
Replies: 16
Views: 12936

The perfect 300B driver is like the perfect phono!

I suspect neither exist!

cheers,

-- Andrew
by Andrew
Sun Sep 02, 2007 5:01 pm
Forum: Everyones Projects
Topic: DTBs 6B4G
Replies: 361
Views: 220052

Nick wrote:Looking at the Atilla driver stage, its still only passing 5ma though.
I think more like 15-20mA is about right.

cheers,

-- Andrew
by Andrew
Sun Sep 02, 2007 12:02 pm
Forum: Everyones Projects
Topic: DTBs 6B4G
Replies: 361
Views: 220052

Other than the pentode, that aikido driver stage is the same as the one I used to driver the 300b's in Doncaster. In that case it was another 6n6p as JRB front to a aikido, with a ecc40 before that. Simon, the driver you heard driving the 6c33c's was also very similar, in that case it was a ecc83 (...