help with calculation of a LR 318 / 3180uS riaa stage?

mseddon · Joined: 05 May 2005 Posts: 31

Hi Lars, I entered the name of the name d3a tube as per dmtriodep 'D3a/7721' on the component attribute editor line 'Value'. However LTSpice doesnt seem to pick it up. What am I doing wrong?

I tried 2A3 and also doesnt recognise it.

What did you change and where?

Sorry for newbie dumb questions - I feel I am nearly there. (I can get the example circuits running OK).

Everything is place to solder up the phono sage - just want to get final values right.
thanks, martin

reVintage · Joined: 07 Sep 2007 Posts: 336 Location: Sweden

Right click on the tube-name in question and add the correct name from dmtriodep.inc .

mseddon · Joined: 05 May 2005 Posts: 31

Heyhey! OK, it runs! - was doing it OK, just didn't include the word 'triode'. Doh!

Unfortunately no current - jeez its easier breadboarding...aargh

martin

reVintage · Joined: 07 Sep 2007 Posts: 336 Location: Sweden

Right click ".ac....." and go for "dc op pnt"

mseddon · Joined: 05 May 2005 Posts: 31

Hi Lars, I can get to see the numbers for the DC op points, but there is no voltage drop across the loads.

The AC sim seems to do plot the output graph OK (looks like neg riaa).

What is the procedure to check if the riaa EQ is correct?

thanks, martin

mseddon · Joined: 05 May 2005 Posts: 31

Halleluya! Praise the Lord - I think I finally got it. Only took 4 days. All currents running and riaa looking good. Will never have to make a real amp again. You gotta go into the ascii file and find out how to name the parts, then it's all hunky. well signing off for now, might even get a phono stage out of this. thanks for your help Lars, all - if ever you want some horns drop me a line.
martin

reVintage · Joined: 07 Sep 2007 Posts: 336 Location: Sweden

mseddon · Joined: 05 May 2005 Posts: 31

azurahorn.com - have sent 2 pairs to Norway. martin

sbench · Joined: 28 Jan 2005 Posts: 191

mseddon · Joined: 05 May 2005 Posts: 31

Then what we obviously need is a large selection of models for each type of tube, so that we can do some tube rolling...

martin
still flushed with success having got my LTSpice phonostage model running...

Just thought - the inverse riaa on the front of teh riaa model, fed into ones real life phono (as described) is just what one needs to test it with a rta sweep. Is this practical?

reVintage · Joined: 07 Sep 2007 Posts: 336 Location: Sweden

Hey,
I vaguely remember Dave mentioning this. Think he was to use it with lower frequensies to get the loadline(oval) with choke/transformer loading.
But maybe it was just a bad dream:) .

mseddon · Joined: 05 May 2005 Posts: 31

Thought I would close this with the finished phono - sounds very rich and alive, compared to CR phono stages I have built. LRC is definitely worth doing. And it's quiet. Cart is Denon 103 to Cinemag 1:14 MMMI-7C input trannie. I used cathode bias to get it going, with OS-Con caps, but can mod to battery bias at some stage. Bass models just a bit down on fixed bias, but doesnt sound it. Just enjoying it for now, and the return to vinyl . Hope someone notices the minimalist style, I rather like it. Just a plate with brass legs. (pls someone delete the earlier pics).

Thanks for the help, martin

reVintage · Joined: 07 Sep 2007 Posts: 336 Location: Sweden

Hello Martin,

Looks like a bombproof build, but why not boxed?. Minimalistic: Yes, but mini: No: wink: . Must weight a lot due to the hefty iron.