audio-talk

Just chiming in to say my P7s need 50mA for max drive and about 1-5 mA in practice to be loud!

Happy New Year!

James still lurking around

Glad your feeling better Phil... us old foggies need to take care of ourselves... I'm just getting back to normal from my reaction to the 4th COVID booster I had 4 months ago - touch and go for a while but seem to be getting better now. Funny thing was it took out my ability to communicate and that ...

Really sad news - still at 82 years old he did well. The split with Dave Brock will never be mended now... I love his playing on Space Ritual - as great as I remember from all the Hawkwind concerts I went too... Space Ritual.jpg Listening to this again also reminds me how good Lemmy was at anchoring...

Very interesting design and it prompts a couple of questions - as ever! I experimented with ring circle small drivers myself and found it can work well, it did have some lobbing measurable but not audible to my ears. Questions that occurred to me are: 1) What were your thoughts on time aligning the ...

Hi Ray,

Nice design and very nice work!

I have been researching using my Sony's for a Luminaria following your recommendation and it looks very interesting!

ciao

James

Quick aside... RE's compound pair is the Sziklai or complementary pair that I like a lot but it is prone to burst oscillation in its simple form as it has multiple internal feedback paths with lots and lots of gain and very little damping on its hf behaviour - I have found it can be stabilised by a ...

Hi Nick, Thanks for the clarification and indeed the case I was referring to ended up with balanced feedback off each collector circuit and was a Class A PP solid state amplifier but I've had similar experiences with SE SS and valve amps too. My experience is that its easier to optimise the way a st...

Please remember that all the views of and types of feedback are all expressed within the context of the system it is being used in - there is no universal panacea... global feedback, interstage feedback, local feedback, negative feedback, positive feedback, etc. all have their place in ones system b...

Paul...I'll swop my amplifier knowledge and experience for yours... Anytime!

Hi Steve, Its not that your understanding is wrong - what you describe happening is correct but the cause and effect is described the wrong way round for conventional description - although the mathematics of sine waves frequency and phase response allows both descriptions... Conventionally we would...

Agree with Nick - the small value bypass caps are there to ameliorate the phase angle at high frequencies and to keep the feedback negative at those frequencies - it is a side effect that one might consider this as maintaining values of negative feedback across the positive gain bandwidth of the amp...

Yeah telecoms drove a lot of the better triode and pentode designs from USA & European manufacturers...

6SN7 released by RCA in 1939 as an audio tube with datasheet included in the 1940 RCA receiving valve book for the first time. Developed as a double triode version of the 6J5 single triode that was released in 1937 as an audio triode. Later use as suitable for multiple roles including TV sets due to...

In terms of linear valves.... the 6SN7 is as linear as any valve and the 6SL7 is not far behind and more linear than any other IHT with its gain (mu) so brilliant choices... particularly in a GFB circuit.

Its interesting to see the sort of systems that the talented diyer ends up with too - many and various paths to Nirvana!

ciao

James