James asked:


im looking to make many improvements to my amplifier valveking to make pi? custom profile and low, I want the sound to have more? dynamic and I have heard that the capacitors that help a lot and theyre also cheap so? it worth it?

1 Comment so far

1. Saul on June 8, 2009 5:05 am

   In my opinion, a cap job is only really warranted when the caps are old and failing. There is a difference between different types of capacitors, and of course *values* of capacitors, but if you’re looking to improve the tone without changing any of the stock component values, I would not expect a cap job to produce the kind of tonal differences that, say, swapping out tubes would.

   Those who have done cap jobs say that things like mil-spec metal film resistors will give a smoother sound than your average electrolytics… but sometimes that grittier sound actually *contributes* to the tone! If you want a grittier, raunchier, fatter sound, I wouldn’t do a thing to your caps. If you want a smoother, more “hi fi” sound, with possibly (possibly!) slightly better treble response, then sure, look at upgrading your caps. I would assume that relatively cheap caps are already in your amp, though, so if you’re going to do a cap job, you better buy the good ones if you’re going to expect any kind of tone upgrade!

   The most significant tonal differences you can make to a tube amp are, in my opinion, swapping out tubes, upgrading the output transformer, and changing a tube rectifier to a solid state rectifier. I would focus my efforts on those first before you start thinking about things like a cap job or altering specific component values.

   Beyond that, power filtering. Upgrading your power filters might be another area to focus on – I would also look at this before I looked at a cap job. I’m not a big fan of “amp sag” (or speaker breakup, for that matter) and I prefer a more modern tone, and that means plenty of dependable solid-state rectifier power, plenty of headroom in the (well-filtered) power supply, and a high quality output transformer that won’t saturate… just like my speakers… I want speakers that are rated for 2-3 times whatever the wattage of my amp is, and an output transformer that is ideally rated at least 20% above the amp’s output as well. Not hard and fast rules, but more headroom will improve clarity and bass response in both situations.

   Feel free to email me if you are interested in doing these but aren’t sure where to start – I have a bit of knowledge/experience in this area, and might be able to offer suggestions/advice for you.

   Saul