Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Woodrow F Call on June 27, 2023, 09:38:13 am

Title: Matching Phase Inverter Coupling Caps?
Post by: Woodrow F Call on June 27, 2023, 09:38:13 am

Well, I'm at the beach and spending my vacation reading about tube amps and playing guitar.

I'm researching to figure out how I'm going to mod a blues junior when I replace the crispy tube board.

In "Inside Tube Amps" by Dan Torres, he talks about matching the phase inverter coupling caps..... looking, the appropriate instrument is pretty expensive and nobody seems to offer such a service.

Is this something that is actually worth doing?

Title: Re: Matching Phase Inverter Coupling Caps?
Post by: sluckey on June 27, 2023, 10:03:02 am

I like to use the same size and color.   :icon_biggrin:

Title: Re: Matching Phase Inverter Coupling Caps?
Post by: Woodrow F Call on June 27, 2023, 11:29:04 am

Quote from: sluckey on June 27, 2023, 10:03:02 am

I like to use the same size and color.   :icon_biggrin:

Lol. I guess it's not a thing to match them any further. Thanks!

Title: Re: Matching Phase Inverter Coupling Caps?
Post by: dwinstonwood on June 27, 2023, 11:40:12 am

You could use 5% tolerance caps like these:
https://www.mouser.com/ProductDetail/Panasonic/ECQ-E4223JFW?qs=9ouE0kzBZ2r6dmZAoqVSQA%3D%3D

I'm definitely far from an expert, but I think exact matching is more important in HiFi, like in phono preamps, etc.

Title: Re: Matching Phase Inverter Coupling Caps?
Post by: echuta13 on June 27, 2023, 01:01:41 pm

I agree its more of a Hi-Fi thing to match up caps.  I think It could be argued that unless you are going for a Hi-Fi sound,  that you may get more complexity from some mismatch in components which could be a desired thing (especially in a guitar amp).   I probably wouldn't dwell on stuff like this too much unless you have tons of time and like rabbit holes (which can be fun!)