audio-talk

Good stuff Phil - looks like the project is working out well.

Ray P wrote: ↑Thu Jul 09, 2020 6:49 pm Good stuff Phil - looks like the project is working out well.

Thanks Ray.

I drilled and tapped the mosfet and PCB mounting holes and populated the second PCB a while ago, but that's it for tonight.

The MOT spade terminals were smaller than I realised, so I've "bodged" them until the proper 4.8mm ones turn up

I'd like to think I'll have stereo MoFo's this weekend.

I've just fired up the second unit, and I'll leave it playing on the test bench for an hour before tweaking the bias to its final value.

I don't anticipate getting them set up in the main system tonight, but something to look forward to in the morning.

Well, of course, I couldn't wait till the morning.

I'm playing a Carpenters CD, and the sound quality is different from what I'm familiar with.

Seems clearer, and more expansive. Bass is clearer, and a bit more of it, but it's not prominent. Karens voice is even more delightful than I remember. Can't find any disadvantages at the moment.

Obviously need more listening time with different types of music to really get a handle on things.

I found it's a nice mix .. I think mine combines all the advantages of no output transformer valve amp and what solid state aspires to be.. . If that makes sense
No colour/ greyness/ lack of detail

Stereo MoFo's.

After a bit of thought I went for the BIG 6800uf capacitors, and mounted them as close to the PCB as possible.

I've switched off now, 'cos I'm going for a walk soon.

I've tried a varying selection of my musical tastes, but as I'm liking what I hear I'll play some more when I return.

I'm considering getting a pair of Hammond 193V chokes, 150mH @ 3A, now that the amp is worth refining.

What chokes did you use Steve ?

I used 193t, I cant imagine a bigger choke will make it sound any better unless you need more power

pre65 wrote: ↑Sat Jul 11, 2020 11:30 am Stereo MoFo's.

steve s wrote: ↑Sat Jul 11, 2020 3:24 pm I used 193t, I can't imagine a bigger choke will make it sound any better unless you need more power

You may be right Steve.

if you really must tinker with it why not try a couple of exicons. I'm willing to bet it will be more enlightening than a couple of expensive chokes. They might cost you £4 each but well worth the experience.

Thanks Ed, but I don't have the skills to select one that would work, and then it's a gamble.

I'll stay with what I've got for now.

ed wrote: ↑Sun Jul 12, 2020 5:21 pm if you really must tinker with it why not try a couple of exicons. I'm willing to bet it will be more enlightening than a couple of expensive chokes. They might cost you £4 each but well worth the experience.

Reading up, my impression is there are advantages to having the choke there, it works similar to choke loading a valve ?
Also reading DIY audio, mosfets can start to sound a little grey when used as a voltage gain amplifying device...thats only what I've read so dont shoot me down... but this thing does not sound grey, just very open.
The amp sounds different.. I think it's good,
But what to I know..
If i messed with a suitable exicon or any other mosfet (unless I was sure otherwise) I'd probably still put a choke with it.. I like what it does

Unless I am missing something, that circuit wont work without a choke. I think ed means use a different mosfet as the power device.

Nick wrote: ↑Sun Jul 12, 2020 7:18 pm Unless I am missing something, that circuit wont work without a choke. I think ed means use a different mosfet as the power device.

One of my many skills is misreading nick, my apologies Ed..