Search found 304 matches
- Sat Oct 08, 2022 12:58 pm
- Forum: Technical Discussion
- Topic: Circuit Analysis Jim Kelley Amp
- Replies: 22
- Views: 7216
Re:
Looking at the 30/60 schematic,I noticed the 6V6 screens are tied to B+ via a 2k/10w resistor. Why is it done like this,and not supplied from a lower voltage stage? 450v plus is really hard on 6V6 screens I think, Jim has used a given PT w/o a 2nd lower HT secondary, presumably a PT designed for us...
- Tue Jan 01, 2013 2:48 am
- Forum: Technical Discussion
- Topic: Lar/Mar PPIMV
- Replies: 68
- Views: 18977
Re: Lar/Mar PPIMV
Thank you!Reeltarded wrote:Larry! Happy New Year, buddy!!!
Happy New Year 2013 to all of you out there!
Wherever you are on this planet!
Larry
- Mon Dec 31, 2012 5:15 pm
- Forum: Technical Discussion
- Topic: Lar/Mar PPIMV
- Replies: 68
- Views: 18977
Re: Lar/Mar PPIMV
Is there some reason that the shielding is connected to the bias voltage? Would it be as effective or even more so if it were attached to ground? I ask because after installing it on an express build I'm getting what is obviously feedback or low frequency (~300Hz) parasitic oscillation when the Mas...
- Mon Dec 31, 2012 5:07 pm
- Forum: Technical Discussion
- Topic: Lar/Mar PPIMV
- Replies: 68
- Views: 18977
Re: Lar/Mar PPIMV
Using the shield to carry the bias voltage is an interesting idea that was not part of the original design. Off-hand I can't see a problem with that. Usually I don't use shielded wires by putting in a PPIMV into an amp, I just twist the cables and additional I'm running the twisted bundles close to...
- Mon Dec 31, 2012 5:00 pm
- Forum: Technical Discussion
- Topic: Lar/Mar PPIMV
- Replies: 68
- Views: 18977
Re: Lar/Mar PPIMV
It's the same when it's turned all the way up, but as you lower the volume the resistance to ground will increase, which will change the load on the PI. Thanks Martin. I think I will try it both ways and listen for the difference... dual 250Ks are delayed in transit. Martin is right and it's worth ...
- Sat Oct 02, 2010 7:52 pm
- Forum: Technical Discussion
- Topic: AO 35 into Spitfire master volume issue
- Replies: 16
- Views: 5637
Re: AO 35 into Spitfire master volume issue
A loud YUPP to the post beyond! Give me a pen, so that I can sign it 8) But... @ Gaz! When your Lar/Mar PPIMV in a marshall-esque fixed bias amp sounded like crap, then there's been either something wrong? Some simply forget to remove the cables from the coupling caps to the output grids :wink: Or y...
- Mon Jan 26, 2009 11:47 pm
- Forum: Dumble Discussion
- Topic: Dumble wrote a chapter for TUT6!?
- Replies: 13
- Views: 2507
Re: Chapter 6
A noteworthy exception is Dave Funk's book, which was probably from around that time as well. I still have it and I've always had the impression that Dave knows very well what he talks about. So Dave, if you're reading this, hats off to you, my friend. Too bad you never published part 2 of your wor...
- Tue Jan 13, 2009 6:54 pm
- Forum: Technical Discussion
- Topic: 1meg vol. pot vs 500K ?
- Replies: 6
- Views: 3706
Re: 1meg vol. pot vs 500K ?
... and makes the input of the next stage highly sensitive for catching all kind of noise!tubedogsmith wrote:If you use the 500k pots run a 470k resistor off the wiper. It will slow down the taper a bit but will work fine, you may even like it better.
Not a good idea IMO!
Larry
- Tue Jan 13, 2009 6:49 pm
- Forum: Technical Discussion
- Topic: Soldering the Unsolderable
- Replies: 6
- Views: 1940
Re: Soldering the Unsolderable
Dimp the contacts into silver cleaner fluid for a few seconds and then wipe it off w/ a paper towel. Sanding removes the galvanic coating and the basic metal doesn't solder very well.
Larry
Larry
- Sat Jan 10, 2009 5:04 am
- Forum: Dumble Discussion
- Topic: 70w Fender OT
- Replies: 12
- Views: 1716
Re: 70w Fender OT
the prim. impedance is 8k8 , so I could use the 16 ohm tap with my 8 ohm Altec for 4k4.I wonder if anyone of you has experience with this model. Just seen your post. No prob to use the OT w/ 2*6L6 as a 4.4K prim w/ 8 ohms load on the 16 ohms secondary, but it might be, that it saturates earlier as ...
- Mon Jan 05, 2009 10:46 pm
- Forum: Dumble Discussion
- Topic: D'lite 6L6 build: Bright!
- Replies: 45
- Views: 6167
Re: D'lite 6L6 build: Bright!
Wow that amp must have had a lot of brightness hitting the OD to warrant 390pf snubbers. I went step by step, first raised to 330p both - still brittle. Then 360p both, but still too brittle. Raised only the OD1 to 390p, but not enough - hence both now 390p. After this I've still heared some slight...
- Mon Jan 05, 2009 9:47 pm
- Forum: Technical Discussion
- Topic: mesa inverter bias
- Replies: 3
- Views: 1482
Re: mesa inverter bias
Exactly!Wayne wrote:More headroom, maybe?
It's the same advantage as a for the same voltage enhanced supply voltage to the PI's plate R's - but an enhanced supply voltage not always is a benefit tonewise.
Larry
- Mon Jan 05, 2009 9:18 pm
- Forum: Dumble Discussion
- Topic: D'lite 6L6 build: Bright!
- Replies: 45
- Views: 6167
Re: D'lite 6L6 build: Bright!
Last summer I've refined a Ceriatone for a buddy. Besides other minor tweaks I've put in a slightly lo-cut to the OD section, an additional .022 after the relay to the OD's entrance (with a 4.7M pop suppressing R to ground at the relay's side), to tame the amp's boomyness. But I couldn't get rid of ...
- Sun Jan 04, 2009 1:33 pm
- Forum: Garage Talk
- Topic: I'm broke but you may not be
- Replies: 11
- Views: 2977
Re: I'm broke but you may not be
Yesss! This one I've meant! Thanks Gary!gahult wrote:That's the F-14.
Larry
- Sun Jan 04, 2009 12:35 am
- Forum: Garage Talk
- Topic: I'm broke but you may not be
- Replies: 11
- Views: 2977
Re: I'm broke but you may not be
Ой блин! I'm not an expert concerning military stuff! I've meant the bird, Michael J. Fox was flying in that one film. Was it Top Gun? Was it a F18? A MIG29?Aurora wrote:F16 is single blaster.....novosibir wrote:Looks like a F16 from behind
Larry
Larry