Metropoulos Forum

Hi all. Is it safe/possible to change the two 0.68 uf caps in Metro 50w to two 0.47 uf, and in case, what difference would it make?

Yes it is possible...I have done it myself with different values such as .47 and .33uf on the cathodes. I unsoldered the .68's and used alligator clips to try various sizes but ended up liking the .68 the best. By dropping down to a .47 you shift the frequency of the mid boost that the caps provide but only you can say if you will like the sound. There is also very little voltage (couple volts) on the cathode so virtually any lower voltage cap will be fine.

Thank you. I have two Mullard Mustard 0.47 that I wanted to use. Change the other caps to Mustardcaps changed the amp for the better, in my ears.

I also have mustards in my two builds for tonal reasons but in the cathode position you may not notice much difference between brands. I am running several different brands of caps in that position and cannot tell much difference in tone between them. Changing the value will make a noticeable change though, so you may want to only do one cathode at a time and try the amp first before changing both. Let us know how you like those values in that spot.

Yes I will. It would also be interesting to see what parts of the amp controls what. What influences treble and volumes etc?