Search found 571 matches

by RhythMick
Mon Mar 09, 2020 7:08 am
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 1114
Views: 135601

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

Allow 4v for regulation. So for a 300B (5v + 4v) is 9v peak, over 1.414 is 6.36v RMS 6.3v tx should be ok. 6v might be if your primary is 5% high. I went for a dual 7v toroidal with 4.4A secondaries to give plenty of headroom. I also used the 63mm heatsinks for the 300B. These are onboard the smalle...
by RhythMick
Sun Mar 08, 2020 7:25 pm
Forum: Everyones Projects
Topic: DHT Heater using VCCS - PCB or Kit (Possible Group buy)
Replies: 1114
Views: 135601

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

I can also highly recommend Andrews boards. I run the standard boards (as opposed to the large) with 300B no issue. Make sure you size the transformer with plenty to spare - I had a buzz which eventually tracked back to toroidal overload.
by RhythMick
Sun Mar 08, 2020 4:05 pm
Forum: Everyones Projects
Topic: New old px4 amp
Replies: 9
Views: 466

Re: New old px4 amp

Very nice. Next Owston?
by RhythMick
Thu Feb 27, 2020 2:11 pm
Forum: Everyones Projects
Topic: yet another boring one trick pony turntable build
Replies: 87
Views: 8757

Re: yet another boring one trick pony turntable build

I have a MOTH machine. Haven't used it for ages.
by RhythMick
Thu Feb 20, 2020 6:02 pm
Forum: Everyones Projects
Topic: GM70 PP
Replies: 151
Views: 12963

Re: GM70 PP

Nice work and nice result.
by RhythMick
Sun Feb 09, 2020 5:37 pm
Forum: Everyones Projects
Topic: GM70 PP
Replies: 151
Views: 12963

Re: GM70 PP

I know it's obvious, but won't the change of rectifier change the operating points of the valves? Especially changing tube to SS.

If you're really wanting to compare the sounds of rectifier circuits wouldn't you need to regulate the HV ? Maybe you already do?
by RhythMick
Wed Nov 20, 2019 5:15 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 808
Views: 76893

Re: Remember These?

Capture.PNG
Page 483 of the RDH v4 confirms... not that I've yet grokked the other formulae on that page
by RhythMick
Wed Nov 20, 2019 4:15 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 808
Views: 76893

Re: Remember These?

470nf into 39k gives 9Hz, about right. Maybe could be lower, but its parts box stuff. Again I'm showing where my understanding may be flaky - I just love doing that ! :D I thought the equation for the -3db frequency corner was 1/(2pi*R*C)... where R is the parallel resistance of anode load and grid...
by RhythMick
Wed Nov 20, 2019 3:15 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 808
Views: 76893

Re: Remember These?

Thanks for sharing the circuits. I would love to try an OTL in a year or so, watching this with interest. What speakers do you intend to drive with this? I’m driving my 8 Ohm Fane single driver speakers. These are 100dB efficient have a flat impedance characteristic and never drop below 7.4 Ohms. T...
by RhythMick
Wed Nov 20, 2019 3:12 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 808
Views: 76893

Re: Remember These?

coupling caps are 470nF ? Am I reading that right ? Should it be uF ? 470nf into 39k gives 9Hz, about right. Maybe could be lower, but its parts box stuff. Again I'm showing where my understanding may be flaky - I just love doing that ! :D I thought the equation for the -3db frequency corner was 1/...
by RhythMick
Wed Nov 20, 2019 1:49 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 808
Views: 76893

Re: Remember These?

Thanks for sharing the circuits. I would love to try an OTL in a year or so, watching this with interest.

What speakers do you intend to drive with this?
by RhythMick
Wed Nov 20, 2019 1:46 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 808
Views: 76893

Re: Remember These?

coupling caps are 470nF ? Am I reading that right ? Should it be uF ?
by RhythMick
Sat Nov 16, 2019 11:10 pm
Forum: Everyones Projects
Topic: Steampunk!
Replies: 7
Views: 967

Re: Steampunk!

Mike H wrote:
Sat Nov 16, 2019 10:16 pm
Likewise!

Image

Here's some possible inspiration...
-
Cholmondeley Arms_2078c.jpg
-

It's a lamp, is all :D
Brilliant
by RhythMick
Sat Nov 16, 2019 9:44 pm
Forum: Everyones Projects
Topic: Steampunk!
Replies: 7
Views: 967

Re: Steampunk!

Watching
by RhythMick
Thu Nov 14, 2019 11:24 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 808
Views: 76893

Re: Remember These?

Cressy Snr wrote:
Thu Nov 14, 2019 7:29 pm
Nah it looks fecking horrible.
I took it off. It looked like a pair of chokes with a chip basket over them. :lol:

It’s now been cut down in height, and turned through 90 deg.
Much better.
I actually spat my tea then ... ROFL