Search found 554 matches

by diagrammatiks
Sun Dec 16, 2012 4:06 pm
Forum: Technical Discussion
Topic: Is the Triode universal PT good for an AC30?
Replies: 8
Views: 1536

Re: Is the Triode universal PT good for an AC30?

The 580 tap will be fine if you use a tube rectifier.

if you solid state rectify the voltage for el84s will be a little high.

They won't be higher then what some amps run el84s at though. As long as you pay attention to your biasing it shouldn't be a problem.
by diagrammatiks
Fri Dec 14, 2012 3:16 pm
Forum: Technical Discussion
Topic: psych effects of pot taper and perceived amplifier power
Replies: 24
Views: 5688

Re: psych effects of pot taper and perceived amplifier power

I think fender used a linear volume and master pot on early revisions of the hot rod deluxe series, not sure if they still do... the result was that the amps would be insanely loud at before the pot was even turned halfway..but not much louder after. gives the illusion of a beefy amp if people think...
by diagrammatiks
Mon Jun 25, 2012 10:23 am
Forum: Technical Discussion
Topic: Black Spragues
Replies: 8
Views: 1908

Re: Black Spragues

The red ones should say 160p somewhere on them. Those are the good ones to use.

Some of the yellow ones are ok too but it depends on the era. They usually have much higher voltages.
by diagrammatiks
Sat Jun 16, 2012 5:56 am
Forum: Technical Discussion
Topic: cathode follower vs. plate driven tone stack
Replies: 8
Views: 12355

Re: cathode follower vs. plate driven tone stack

you're more likely hearing the difference between series overdriven regular stages versus the overdriven cathode follower more so then the effect of tone stack loading. The difference to the tone stack in a marshall circuit is almost negligible but not having that cathode follower is going to have a...
by diagrammatiks
Fri Jun 15, 2012 9:53 pm
Forum: Technical Discussion
Topic: OT impedance
Replies: 20
Views: 3374

Re: OT impedance

You cannot use a DVM and measure the DC resistance to determine impedance ratio. DC resistance of teh windings tells nothing about impedance, or rather turns ratio. DC measurements can only briefly tell if the trafo is not shorted or burnt. If there are som specs printed on the trafo, or if you hav...
by diagrammatiks
Fri Jun 15, 2012 9:44 pm
Forum: Technical Discussion
Topic: OT impedance
Replies: 20
Views: 3374

Re: OT impedance

you have to determine the reading on the primary and then the secondary. that sets up a ratio between the two windings. if your primary reads 600ohms and your secondary reads 4 ohms then that's a 600:4 ratio. That means if you hook up a 4 ohm speaker to the secondary the primary will see 600 ohms. I...
by diagrammatiks
Fri Jun 15, 2012 9:38 pm
Forum: Technical Discussion
Topic: OT impedance
Replies: 20
Views: 3374

Re: OT impedance

sorry you said 4:600 in your original post.

that would be 2:300, 4:600, 8:1200, 16:2400
by diagrammatiks
Fri Jun 15, 2012 9:04 pm
Forum: Technical Discussion
Topic: OT impedance
Replies: 20
Views: 3374

Re: OT impedance

you can't measure it like that.

it's just a ratio.

8:600, 16:1200, and 4:300 are functionally the same transformer.
by diagrammatiks
Fri Jun 15, 2012 8:50 pm
Forum: Technical Discussion
Topic: Why so little Gibson amps clones ?
Replies: 30
Views: 11376

Re: Why so little Gibson amps clones ?

I would guess because they weren't that popular or widespread to begin with and therefore not a lot of people are looking to buy clones. In the US the used prices on the Gibson amps are fairly low. That being said the amps aren't hard to build, not any harder then any of the other amps that are usua...
by diagrammatiks
Fri Jun 15, 2012 8:49 pm
Forum: Technical Discussion
Topic: OT impedance
Replies: 20
Views: 3374

Re: OT impedance

are you sure it's not 8ohm at 1.2k?
by diagrammatiks
Mon Jun 11, 2012 4:33 am
Forum: Technical Discussion
Topic: Can anyone ID this capacitor type ?
Replies: 3
Views: 1066

Re: Can anyone ID this capacitor type ?

it's an epcos b32592 metalized polyester.
by diagrammatiks
Sun Jun 10, 2012 11:51 pm
Forum: Technical Discussion
Topic: Can anyone ID this capacitor type ?
Replies: 3
Views: 1066

Re: Can anyone ID this capacitor type ?

that's already a film capacitor.
by diagrammatiks
Sun Jun 10, 2012 10:39 pm
Forum: Technical Discussion
Topic: small vs large fuses ??
Replies: 9
Views: 1802

Re: small vs large fuses ??

radioshack and home depot have littelfuses they are less then a dollar, usually 4 for 2 or 3.

pretty common things now a days.
by diagrammatiks
Sun Jun 10, 2012 10:37 pm
Forum: Technical Discussion
Topic: looking for an amp that has the following topology.
Replies: 11
Views: 2459

Re: looking for an amp that has the following topology.

the pi is usually already a gain stage and provides enough recovery for the tonestack usually.

otherwise a cathodyne usually has a coupled driver tube in front of it.

hiwatts use a driver stage into the dc coupled phase inverter.
by diagrammatiks
Sun Jun 10, 2012 10:02 pm
Forum: Dumble Discussion
Topic: Does shielded wire really kill your tone?
Replies: 23
Views: 5342

Re: Does shielded wire really kill your tone?

If you just use a ground shield inside the amp that is grounded at one end and is non essential for the ground returns then you will get significant capacitive coupling. I don't follow, diagramatiks. Can you explain how the capacitive coupling to ground will be other than the capacitance per unit l...