Got a brand new Toy!

syscokid said:
Nice update pics. I really can't see anything wrong. You mentioned the larger value bias pot. That will still work, but it'll be more touchy when you're trying to adjust the bias.
Click to expand...
Like @Amp Mad Scientist suggested: ill pop open the speaker cab and check the resistance on the speakers individually and then the total for some peace of mind and to potentially rule out a screwed up impedance issue, since its 25 years old. Also changing the power tube sockets wouldnt be a bad choice either if some carbon is built up within.

Beyond that? Im hoping it was just a fluke from a bad tube being pushed too hard. The fuses got me screwed over until they ship lol
 
Clockworkmike said:
It is very possible there could be some break down internally at the cabinet, i certainly wouldnt rule that out considering its at least 25 years old
Click to expand...
Does the cab in question have one of those switchable jack plates?
070A6971-7E0A-4902-89EE-075720F6855A.jpeg

I had one fail on me a few years back...it was a weird and spooky kinda thing. I replaced it with something different, and no problems since...
 
Thatbastarddon said:
Does the cab in question have one of those switchable jack plates?
View attachment 58291

I had one fail on me a few years back...it was a weird and spooky kinda thing. I replaced it with something different, and no problems since...
Click to expand...
Yes sir it unfortunately does. Ive heard lots of conflicting things over them, like the switch internally screws up and sticks to one impedance ( stereo when you want mono) even when you switch to another. That is certainly something im gonna check with my meter and the amp's impedance switch too. Highly possible either one could be sticking
 
Clockworkmike said:
Yes sir it unfortunately does. Ive heard lots of conflicting things over them, like the switch internally screws up and sticks to one impedance ( stereo when you want mono) even when you switch to another. That is certainly something im gonna check with my meter and the amp's impedance switch too. Highly possible either one could be sticking
Click to expand...
Mine would randomly change impedance under load...if it were me....I’d get it out of there immediately. But I am biased by my personal experience with only one. It was difficult to test because it only did its weirdness under load at first...but I caught it by testing the lead immediately after shutting down during what I was hearing as symptomatic behavior. Sure enough it was switching itself internally(shorting or whatever). I replaced it with one of these:
1612716821265.png
...it required enlarging the mounting hole vertically....and I haven’t looked back.
:cheers:
 
Thatbastarddon said:
Mine would randomly change impedance under load...if it were me....I’d get it out of there immediately. But I am biased by my personal experience with only one. It was difficult to test because it only did its weirdness under load at first...but I caught it by testing the lead immediately after shutting down during what I was hearing as symptomatic behavior. Sure enough it was switching itself internally(shorting or whatever). I replaced it with one of these:
View attachment 58306
...it required enlarging the mounting hole vertically....and I haven’t looked back.
:cheers:
Click to expand...
No bueno por caca
 
Clockworkmike said:
Yes sir it unfortunately does. Ive heard lots of conflicting things over them, like the switch internally screws up and sticks to one impedance ( stereo when you want mono) even when you switch to another. That is certainly something im gonna check with my meter and the amp's impedance switch too. Highly possible either one could be sticking
Click to expand...

A. You plug a good speaker cable into the cabinet.
B. You connect the ohm meter to the end of the speaker cable.
C. For a 16 ohm cabinet, the meter should read 12.6 ohms approximately.

FLEX test DO THIS

with the meter connected as above, move the cable plug up and down, left and right.
Wiggle the plug around where it is connected into the cabinet. Flex the cable around in different directions.
The ohm reading should stay steady. Very little variations.

If the ohm reading jumps around wildly when the cable or plug is flexed:

Replace the cabinet jack, or whatever you need to do to obtain a steady solid reading.
The ohm reading MUST remain solid steady - no matter how much the cable or plug is flexed.

This is called a "flex test."
This is an industry standard test to verify reliability of a connector or cable.
Every cable or connector that is manufactured - is subjected to this test.
And, this is an extremely important test.
 
Amp Mad Scientist said:
A. You plug a good speaker cable into the cabinet.
B. You connect the ohm meter to the end of the speaker cable.
C. For a 16 ohm cabinet, the meter should read 12.6 ohms approximately.

FLEX test DO THIS

with the meter connected as above, move the cable plug up and down, left and right.
Wiggle the plug around where it is connected into the cabinet. Flex the cable around in different directions.
The ohm reading should stay steady. Very little variations.

If the ohm reading jumps around wildly when the cable or plug is flexed:

Replace the cabinet jack, or whatever you need to do to obtain a steady solid reading.
The ohm reading MUST remain solid steady - no matter how much the cable or plug is flexed.

This is called a "flex test."
This is an industry standard test to verify reliability of a connector or cable.
Every cable or connector that is manufactured - is subjected to this test.
And, this is an extremely important test.
Click to expand...
Will do!
 
Amp Mad Scientist said:
A. You plug a good speaker cable into the cabinet.
B. You connect the ohm meter to the end of the speaker cable.
C. For a 16 ohm cabinet, the meter should read 12.6 ohms approximately.

FLEX test DO THIS

with the meter connected as above, move the cable plug up and down, left and right.
Wiggle the plug around where it is connected into the cabinet. Flex the cable around in different directions.
The ohm reading should stay steady. Very little variations.

If the ohm reading jumps around wildly when the cable or plug is flexed:

Replace the cabinet jack, or whatever you need to do to obtain a steady solid reading.
The ohm reading MUST remain solid steady - no matter how much the cable or plug is flexed.

This is called a "flex test."
This is an industry standard test to verify reliability of a connector or cable.
Every cable or connector that is manufactured - is subjected to this test.
And, this is an extremely important test.
Click to expand...
Mine failed the flex test without flexing. Readings fluctuated between 2-36 Ohms with no movement. Dead switch.
Removed & replaced....problem solved.
I am not saying that it is the problem, but warning that it can be a hidden contributor.
Mine had passed the test(flex or non-flex) twice before the above noted failure, while exhibiting symptoms(changes in volume and/or tone briefly). Everything metered out as expected the first two checks I ran...I swapped amp heads(and speaker cable), and when it happened a third time I got the flux readings I mentioned. @Clockworkmike - That is what I meant by “weird and spooky”
 
steveb63 said:
AMS, I'm hoping that attenuator isn't the culprit?

Was working fine the night before I shipped it out.

@Clockworkmike is a sharp guy, I'm sure he had the connections and ohmage correct.

Man, I'm sorry Mike.
Click to expand...

I have a Weber Mass Lite 100 that will attenuate my 50 watt Marshall to zero volume. I've used it on my DSL40C's for years with no issues.

I seriously doubt the attenuating is to blame...IMHO
 
You must log in or register to reply here.
Back
Top