Print PDF
Favorite
Email
Step 7Replacing 'the other' caps
Other than the filter capacitors, the other caps in the amp will be one of these (Step 8 will help you identify each of these types) :
1) Coupling Caps -- connect the signal path between stages
2) Tone Caps -- roll off different frequencies to ground, for tonal effects
3) Cathode-Bypass Caps -- integral part of "cathode biased" circuits
Most of these caps will be of the non-polarized variety. The occasional cathode bypass cap could be a polarized, however.
The coupling and tone caps should have voltage ratings comfortably higher than the max voltage the circuit might see--with cap and induction spikes, just assume these should be 400 volts or greater.
The bias voltage for tubes rarely exceeds 10-15 volts, however. A 50V capacitor will work fine for the cathode-bypass caps.
Use a 30W soldering iron. Grasp the leads of the old caps (with needle-nose pliers, if you are smart), and apply the iron. They may take some wrestling to remove. If you can avoid cutting the lead, so much the better.
Pulling vs. cutting usually leaves you a hole to insert the new replacement cap. Finagle it in, solder and you're done....
Many people would say I'm a bad boy for not using 'orange drops'....(seriously, the amp sounds much better than before, with the new mylar caps..) I do expect to be criticized for not using them, but the majority of professional amplifier technicians say that the differences are subtle and a matter of taste...
Still, remember these are the caps that the audio signal passes through. So avoid the cheapest ceramic caps, for instance.
1) Coupling Caps -- connect the signal path between stages
2) Tone Caps -- roll off different frequencies to ground, for tonal effects
3) Cathode-Bypass Caps -- integral part of "cathode biased" circuits
Most of these caps will be of the non-polarized variety. The occasional cathode bypass cap could be a polarized, however.
The coupling and tone caps should have voltage ratings comfortably higher than the max voltage the circuit might see--with cap and induction spikes, just assume these should be 400 volts or greater.
The bias voltage for tubes rarely exceeds 10-15 volts, however. A 50V capacitor will work fine for the cathode-bypass caps.
Use a 30W soldering iron. Grasp the leads of the old caps (with needle-nose pliers, if you are smart), and apply the iron. They may take some wrestling to remove. If you can avoid cutting the lead, so much the better.
Pulling vs. cutting usually leaves you a hole to insert the new replacement cap. Finagle it in, solder and you're done....
Many people would say I'm a bad boy for not using 'orange drops'....(seriously, the amp sounds much better than before, with the new mylar caps..) I do expect to be criticized for not using them, but the majority of professional amplifier technicians say that the differences are subtle and a matter of taste...
Still, remember these are the caps that the audio signal passes through. So avoid the cheapest ceramic caps, for instance.
| « Previous Step | Download PDFView All Steps | Next Step » |
 |
Add Comment
|
