Still no break-up. 2x 5F1's.

[Sea Chief]

Can you beg, borrow or steal another MM?

Unfortunately not. I know of no-one who has one.

Ive just seen an OS'scope 10m ditty on YTube and afaict I should be seeing as much as 2 VAC across the gtr cord. Ive ruled out both cables as a bare jack plug (IE w'out either wire attatched) reads the same. 0.1 VAC (or fluctuates to 0.2/ but doesnt change an iota on whacking strings or strings left alone).

Why the MM reads barely anything.. Ive no idea. Im exhausted with this.

Am I doing this 6v6 test/ does it need spkr in, does the vol knob need some vol introduced, or at max? or my 4ohm 7w resistor 'dummy load' in instead?

[Sea Chief]

A DMM like that with only 750V and 200V AC ranges probably doesn't compensate for the diode so it won't measure AC voltages less than a diode Vf.

That sounds entirely logical. Thanks Dave H.

[Dave H]

Am I doing this 6v6 test/ does it need spkr in, does the vol knob need some vol introduced, or at max? or my 4ohm 7w resistor 'dummy load' in instead?

Turn the guitar and amp vol pots to max. It will need a speaker or dummy load. When you get a good voltage on the 6V6 pin 5 try measuring across the dummy load and post the voltages.

[Enzo]

Sea Chief, let me tell you a story from my shop. This absolutely happened, none of it is fiction.


I had an old Crown 300 power amp in, and one channel was not right. I quickly determined one of the power rails was missing in the bad channel. One channel thus lacked V+. On this amp, there are five identical fuse holders across the front. The center one for mains, and the two on either side were V+ and V- for each channel. Power was not making it through one of the fuses. I pulled the fuse, and automatically checked it with an ohm meter. it was GOOD!!! In case I was being confused, I pulled and checked all five fuses with my meter. ALL good. I put them back in their holders - yes, I kept track of which one was in which holder - and the problem remained. So even though I knew the fuse was good, I replaced it with new anyway, and sure enough the amp worked. My curiosity raised, I subbed the "bad" fuse back in and the channel no longer worked. But the fuse tested OK, so I tried it in the other holders. it worked fine in them. I had one good fuse that worked fine in the other four holders, and any fuse other than this one worked fine in THE holder. But that one good fuse would not work in that one good holder. I tried rotating it, I tried end to end flip. I never did figure out just what the issue was.


I called my junior tech over and showed him this mystery. he replied "That is impossible, it can;t be."





ANother story. Not long ago I got in three Blues Juniors, new in the box. Complaint was no sound or distorted sound. I determined that the output jack was at fault. Fender uses a little right angle 1/4" molded plug and wires for the speaker connection. Fender also uses a shorting jack for the speaker, so with nothing plugged in, it shorts the output. What I found in these amps, all had the same issue. The molded plug was ever so slightly undersized, so when plugged into the jack, it didn;t push the tip contact quite far enough to clear the shorting contact. If I turned the plug in the jack, are pressed it slightly sideways, sound returned. A speaker cord with a plain Switchcraft plug om it worked fine in the amp. A simple reformation of the contact cured it. (That is fancy talk for bending it.) Point being that the plug is a regular old 1/4" male, it worked on almost all the amps, but not these three. The jack worked. This molded one works too, if I form the contact a hair. So working parts once again decide not to work with each other.


So don't overlook the possibility that your good guitars with your good cords into your good input jacks still might not work together.

[Sea Chief]

But Enzo my gtrs do work. They work fine in amp1 and amp2*. They work in my other 2 amps too & they sound good. Nothing untoward/ no odd noises/ no odd gtr volume/ no cable occasionally not connecting; the gibson sounds louder than the strat exactly as expected, not more, not less. I had a danelectro '59 J.PAge type reissue 2 years ago that sounded fine too, and hot pickups those: this gtr made amp1 get the most distortion a volmax, a mild OD Id almost say (but nothing so much as so 'exciting' at all- you had to dig in at full pelt to get it).

*just with no distortion until vol 9.5.

I am -only- concerned here on this thread with amp2. A plain jane 5F1.

So, 3 guitars that work fine then.. and still your adamant my problem lies here? No.

[Sea Chief]

Can you beg, borrow or steal another MM?
Meanwhile, with your current MM, measure VAC at 6V6 pin 5 (with black probe grounded to chassis). Plug the guitar in and hit a power chord. What does the meter read?

Nothing. 0.1 Vac. (Should I be reading DC then?)

WTF with this amp?

[DrGonz78]

Quick Question... Have you posted a clip of what the amp(s) sound like recorded? Perhaps you did but I scanned through and did not see.

[Sea Chief]

Quick Question... Have you posted a clip of what the amp(s) sound like recorded? Perhaps you did but I scanned through and did not see.

Amp.

No. I have no idea how to do this. Besides, it would just sound fine-but-clean.. clean.. clean up to 9.5 then some distortion just/ finally to 10. Im not sure any recording could say more than this tbh.

Ive just missed the whole of poland vs germany dicking around with this too! argh!! (poland 2-0 germany too :-O)

[Dave H]

Nothing. 0.1 Vac. (Should I be reading DC then?)

WTF with this amp?

Check you have the guitar and amp vol pots set to max and hit a big chord. It will read 0 Vac without an input signal.

And also check your DMM's 200V AC range by measuring the 6.3V heater supply.

[Sea Chief]

Check you have the guitar and amp vol pots set to max and hit a big chord. It will read 0 Vac without an input signal.

And also check your DMM's 200V AC range by measuring the 6.3V heater supply.

Amp vol.. forgot this! Im not used to having it anything but 0.

Ok. 30 VAC at max whackage (to 0 VAC no whackage).

[Sea Chief]

Have I finally put pay to the bad gtr output idea now? (30 vac @ pin 5 of the 6v6).

[Sea Chief]

4.8 vac measured across the 4 ohm dummy load (@ full whackage/ to 0 vac no whackage).

[Dave H]

Have I finally put pay to the bad gtr output idea now? (30 vac @ pin 5 of the 6v6).

Then your 6V6 should be begging for mercy. Now measure the Vac across your dummy load resistor.

[Dave H]

4.8 vac measured across the 4 ohm dummy load (@ full whackage/ to 0 vac no whackage).

Simultaneous posting, 4.8 Vac is about right. It's 4.8^2/4 = 5.76W

[Jazz P Bass]

Just about 6 watts output.
Not bad for a Champ.

Now, just for grins & giggles, remove the feedback resistor.
That should make it crunch earlier in the game.