Search found 4031 matches

by Andrew
Sun May 20, 2018 9:40 am
Forum: Stacks
Topic: DHT Heater Group Buy notes.
Replies: 12
Views: 2799

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: 27
Views: 696

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...
by Andrew
Sat May 12, 2018 1:52 pm
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 988
Views: 66139

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

IslandPink wrote:
Sat May 12, 2018 11:48 am
Good to see you standing up for my principles there Andrew ! :D
My pleasure, Mark ;)
by Andrew
Sat May 12, 2018 10:05 am
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 988
Views: 66139

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

Folks in the group buy, All the parts are here but despite my best efforts to avoid partial deliveries I have ended up with a back order for some of the critical resisters, these are in the area that Mark and myself spent all the time perfecting. When I changed the recipe last time, Mark tore strips...
by Andrew
Wed May 09, 2018 6:12 pm
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 988
Views: 66139

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

Just to be clear, I don't intend to ship the kits with the two current set resistors, please see here http://www.audio-talk.co.uk/phpBB3/viewtopic.php?f=19&t=5500 as I don't know your intended voltage, although I assume your not using an input transformer larger than 9 volts AC; two off 250mWatt gen...
by Andrew
Mon May 07, 2018 7:02 pm
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 988
Views: 66139

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

The parts from the US have arrived, UK based parts to arrive this week.

Hopefully, I should be able to start sending packs out towards the end of the week.

best regards,

Andrew
by Andrew
Mon Apr 30, 2018 1:23 pm
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 988
Views: 66139

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

Quick progress update. I am waiting for delivery of an order from the US for parts not available in sufficient quantity in the UK.

best regards,

Andrew
by Andrew
Wed Apr 25, 2018 8:03 am
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 988
Views: 66139

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

Thanks, chaps, looks like everyone who contacted me has confirmed.

Please consider the group buy closed.

Andrew
by Andrew
Thu Apr 19, 2018 1:16 pm
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 988
Views: 66139

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

Neal, did you still want some?

thanks,

Andrew
by Andrew
Mon Apr 16, 2018 11:39 am
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 988
Views: 66139

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

Yes please, thanks for clarifying that, Nick.

Andrew
by Andrew
Sun Apr 15, 2018 6:22 pm
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 988
Views: 66139

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

OK, now that Easter is behind us I am in a position to start building up the group buy and, all being well, parts availability not withstanding, ship in a week or two. There has been a few changes to the orders and so I have lost track of where we were. For the sake of clarity and to avoid disappoin...
by Andrew
Sun Apr 08, 2018 6:44 am
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 988
Views: 66139

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

I mean are the backs of the transistors live, needing mica spacers?
A isolating spacer is needed unless you replace the D44H11, providing you don't need to be in the upper end of the current specs, the regulator is an all plastic part.

Andrew
by Andrew
Fri Apr 06, 2018 4:45 pm
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 988
Views: 66139

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

So, is it OK to mount the transistors on heatsinks remotely and run wires to the boards? Not sure it would be my first choice; it will certainly increase strays/parasitics and there was a lot of work in the layout of the PCB to keep noise to a minimum. And, don' forget both transistors are carrying...
by Andrew
Wed Apr 04, 2018 7:15 pm
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 988
Views: 66139

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


OK Thanks Andrew - so they are same size (80 x 50mm) and same BOM apart from 2 extra caps and I assume it doesn't include heatsinks as the large boards expect the transistors to be mounted remotely and wired to the solder pads - do I have that right ?
That's correct.
by Andrew
Tue Apr 03, 2018 10:01 pm
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 988
Views: 66139

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

Andrew does it make any difference to the group order which board is supplied? Nope, no problems either way, and this goes for anyone. If you take the small boards and then find you'd prefer the large, I'll happily swap as long as you cover the postage and the PCB are returned unused, or visa versa...