Search found 4044 matches

by Andrew
Tue Jul 03, 2018 4:12 pm
Forum: Everyones Projects
Topic: Adventures in LCR Phonos
Replies: 16
Views: 246

Re: Adventures in LCR Phonos

I would ditch the grid leak bias, that big resistor is a potential source of hum noise, and as the 88 ages it may runaway, especially if you replace the 88 with something with more GM, like D3A. By all means try it as is, but be prepared to chase hum. This is one of those times when a bigger cap and...
by Andrew
Tue Jul 03, 2018 7:33 am
Forum: Assorted Stuff
Topic: Next Owston meet 30 june/1 July 2018
Replies: 174
Views: 5842

Re: Next Owston meet 30 june/1 July 2018

IslandPink wrote:
Mon Jul 02, 2018 8:40 am
I'll meet you half-way : it was two tracks, ie. one LP !
It was plenty ;)

Thanks to Steve for organizing, great to see everyone again.

Andrew
by Andrew
Tue Jul 03, 2018 7:31 am
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 1014
Views: 70063

Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Hi Mick,

I wont' ask what happened. You really need Panasonic FR Series, high ripple, not cheap but worth it.

cheers,


Andrew
by Andrew
Thu Jun 14, 2018 7:51 pm
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 1014
Views: 70063

Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Those remaining are:

Neal : 4 x large
Michael L 2 x large

Neal are you planning on being at Owston?

thanks,

Andrew
by Andrew
Tue Jun 12, 2018 9:35 am
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 1014
Views: 70063

Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

IslandPink wrote:
Tue Jun 12, 2018 8:32 am
Thanks - another 8 would be handy for two more boards. Will you be at Owston ?
Planning to be there.

Andrew
by Andrew
Tue Jun 12, 2018 7:52 am
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 1014
Views: 70063

Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Mark, I've got a also got few spares, if you need them.

Andrew
by Andrew
Tue Jun 05, 2018 7:13 am
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 1014
Views: 70063

Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Hi Mark,

Yes, it's a SK129, select preferred height depending upon required degs/watt and ambient temp.

cheers,

Andrew
by Andrew
Mon Jun 04, 2018 7:58 am
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 1014
Views: 70063

Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Hi Mark, Non epoxy caps, not taking that risk again ;) http://uk.farnell.com/kemet/c2220c474j5gactu/cap-mlcc-c0g-np0-470nf-50v-2220/dp/1679460?ost=1679460&ddkey=http%3Aen-GB%2FElement14_United_Kingdom%2Fsearch Pretty much any green LED, I use the HLMP Y502, data sheet can be found here http://uk.far...
by Andrew
Thu May 31, 2018 7:56 am
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 1014
Views: 70063

Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

I've heard from Mick, anyone else care to choose Owston or the Royal Mail?

best regards,

Andrew
by Andrew
Tue May 29, 2018 8:30 pm
Forum: Stacks
Topic: DHT Heater Group Buy notes.
Replies: 25
Views: 3399

Re: DHT Heater Group Buy notes.

Multimeter measures 115mV AC at the simulated filament (resistor). What's normal? Might be better scoping it. 115mv :shock: that's huge, are you certain it's all ok? The AC component should be tiny, like less than 2mV (from memory) please have look at the FFT graph/imagess in the group buy for refe...
by Andrew
Tue May 29, 2018 8:24 pm
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 1014
Views: 70063

Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

I received a delivery of back ordered parts today so I can start shipping again, I'm still short the 1K Carbons for just two remaining boards and will go hunting for those. I owe..... Mick : 2 x large Thomas: 4 x large Neal : 4 x large davedms: 2 x large Michael L 2 x large For those going to Owston...
by Andrew
Tue May 22, 2018 3:04 pm
Forum: Stacks
Topic: DHT Heater Group Buy notes.
Replies: 25
Views: 3399

Re: DHT Heater Group Buy notes.

The TL series have internal references, the output of the actual device is relative to this reference, which in turn is set by the potential divider on the REF pins.

Andrew
by Andrew
Mon May 21, 2018 10:31 am
Forum: Stacks
Topic: DHT Heater Group Buy notes.
Replies: 25
Views: 3399

Re: DHT Heater Group Buy notes.

Nick wrote:
Mon May 21, 2018 10:07 am
To quote Andrew
The TLV431 should just drop in, the voltage pre-regulator, the LD1085, is referenced from the TL431
Yep, the whole unit is referenced off the TL device, no need for other changes.
by Andrew
Sun May 20, 2018 9:40 am
Forum: Stacks
Topic: DHT Heater Group Buy notes.
Replies: 25
Views: 3399

Re: DHT Heater Group Buy notes.

Well found, Nick.

The TLV431 should just drop in, the voltage pre-regulator, the LD1085, is referenced from the TL431, so you should be good to go. Just set Rx and Ry according for the TLV431 rather than the TL431.

cheers,

Andrew
by Andrew
Mon May 14, 2018 7:00 pm
Forum: Everyones Projects
Topic: 6C33C SE-OTL Project
Replies: 53
Views: 1724

Re: 6C33C SE-OTL Project

I can see there being some potential for distortion with grid current, but can it run away, with a current source in the cathode ? Whats to stop it. at least with a resistor instead of a current source there will be some degeneration to pull it down if it wants to float up, not so with a current so...