audio-talk

Page 483 of the RDH v4 confirms... not that I've yet grokked the other formulae on that page

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...

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...

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/...

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?

coupling caps are 470nF ? Am I reading that right ? Should it be uF ?

Mike H wrote: ↑

Sat Nov 16, 2019 10:16 pm

Likewise!



Here's some possible inspiration...
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Cholmondeley Arms_2078c.jpg
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It's a lamp, is all

Brilliant

Watching

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.

It’s now been cut down in height, and turned through 90 deg.
Much better.

I actually spat my tea then ... ROFL

IslandPink wrote: ↑

Thu Nov 14, 2019 3:39 pm

...it was ECC40 direct-coupled to a 45, which was choke-loaded and cap-coupled to a 300B

I plan to try 45 in that middle position very soon

Interesting. I've started with the view that I'll use relatively inexpensive coupling caps to experiment and get the value right, but I'm skeptical about the effect on the sound of different makes. I'm prepared to give different makes a listen once I've got the value right, but I'm expecting the £7 ...

When I got into amp building a few years ago I did a lot of reading before I got around to building anything. I took away from that reading an aversion to the coupling cap which has until now strongly influenced my amps. Last weekend I changed my DHT SE amp to cap couple V2 (71A) to V3 (300B). The i...

I went with thermistors in the mains primary, bypassed by relay after a few tenths of a second.

BTW, one of the things that makes winding a choke input choke different from a cap input one is the voltage it has to withstand from one terminal to the other, so the way the windings are laid down and insulation between layers becomes important. The Lundahl datasheet quotes "insulation between win...

Why not think about a slow start option?