Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: sean_thornton on June 27, 2014, 04:57:37 am

Title: Question about the 56T and the Little Wing
Post by: sean_thornton on June 27, 2014, 04:57:37 am

The capacitor values shown in the schematics don't indicate if they are microfarads or picofarads. Should I assume they are all microfarads unless noted otherwise?

Title: Re: Question about the 56T and the Little Wing
Post by: tubenit on June 27, 2014, 09:12:05 am

picofarads will typically be indicated with something  like  500pf  or 500p on my schematics.

With respect, Tubenit

Title: Re: Question about the 56T and the Little Wing
Post by: sean_thornton on June 28, 2014, 09:12:58 pm

Thanks Tubenit, so by default any other capacitor is a microfarad (uF), correct?

Title: Re: Question about the 56T and the Little Wing
Post by: PRR on June 28, 2014, 11:58:02 pm

Tube-amp main power supply caps are dozens of uFd (microFarads).

Tube-amp treble tone knob caps are often hundreds of pFd (picoFarads).

Tube amp bass tone control caps are often like a tenth of a uFd. Young guys note this as hundreds of nFd (nanoFarads).

Stage-to-stage coupling caps are often like a tenth or a hundredth of a uFd.

Cathode bypass caps tend to be a dozen uFd, though 0.68uFd is popular for a less-bass (lead) sound.

With these hints you can usually decode the units-style of the drawing. Of course elsewhere on the Web I have seen stuff that just don't make sense.

Title: Re: Question about the 56T and the Little Wing
Post by: sean_thornton on June 29, 2014, 07:30:38 am

Quote from: PRR on June 28, 2014, 11:58:02 pm

Tube-amp main power supply caps are dozens of uFd (microFarads).

Tube-amp treble tone knob caps are often hundreds of pFd (picoFarads).

Tube amp bass tone control caps are often like a tenth of a uFd. Young guys note this as hundreds of nFd (nanoFarads).

Stage-to-stage coupling caps are often like a tenth or a hundredth of a uFd.

Cathode bypass caps tend to be a dozen uFd, though 0.68uFd is popular for a less-bass (lead) sound.

With these hints you can usually decode the units-style of the drawing. Of course elsewhere on the Web I have seen stuff that just don't make sense.

Thanks PRR, i know the rule of thumb you posted but as you said there is stuff out there makes no sense. Luckily Tubenit, Geezer, and the other "mad scientists" on here provide very well thought out circuit and layout diagrams but i hate making assumptions, especially when around high voltage, so when i am in doubt i seek clarification.
We are actually lucky to have the knowledge base this forum provides.