Metropoulos Forum

Anyone tried a Panasonic .68uf cap on V1b in place of the mustard cap? if so got any feedback?

Thanks

Turd

Also I want to try a 100k NFB resistor on the 4ohm tap instead of the 47k any feedback on this?? or should I put the NFB wire on the output jack positive terminal and not the tap what is the difference?

Don't use the jack for NFB. If you use the jack, your NFB depends on the cabinet you're using... so, not a good idea.

I don't like 100k/4ohm by the way...

Thanks
I built a 50 watt using the metro 50 watt instruction and it had the NFB wire to the jack so that is how I did it. are you using a 47k resistor for the NFB? what tap are you using? my 50 watt just sounds ok not what I was expecting it is with 68 specs It needs a little more gain I want to try the 70s specs what are your thoughts?

I personally can't tell much of a difference in the different types of materials for cathode caps. Different values yes but not the brand. Definitely try the 100k on the 4ohm and if it is too much you can try somewhere in between like a 68k instead. When you have it on the jack itself then the NFB changes every time you change the impedance setting. Do you have a ppimv installed on your amp? This will allow you to get a little extra overdrive out of your amp also.

The panasonic .68 uf cathode bypass definately affects the sound/feel to a degree. To use an analogy, you know how back in the day in elementary school, how you would start the year out with whatever supplies (like pencils & paper for ex.) your parents bought you. You remember the pencils with that 'soft' lead ? Even when they were very sharp they just were kinda 'uugghh', ya know ?? Then, you had the pencils with the real hard lead. If they were sharp they were very sensitive......if you press down hard the tip might break. But even then, the pencil wrote so much better because of the lead being harder, etc. Kinda funny 'cause both these pencil/lead types were 'NO.2'
Anyways, I see the mustard (along with Sozo & Mallory) as being more like the soft lead and the panasonic (polypropyline) as being more like the hard lead. It really depends on what you want tonewise. The Panasonic seems a bit more forthright and aggressive (penetrating/bite) while the Mustard is a bit more mellow/warm. A tube amp circuit is most definately a 'balancing act' concerning the whole 'clarity' vs. warmth' type thing imo.

thanks for the replies!!
I am going to break out the iron and do some stuff and some mods and if I don't care for it I can always go back.

Turd

Turd Ferguson wrote:Thanks
I built a 50 watt using the metro 50 watt instruction and it had the NFB wire to the jack so that is how I did it. are you using a 47k resistor for the NFB? what tap are you using? my 50 watt just sounds ok not what I was expecting it is with 68 specs It needs a little more gain I want to try the 70s specs what are your thoughts?

I'm using 47k on the 8ohm tap

Do you have the .68uF across V2's cathode resistor?

yes I do have it on the cathode resistor !! I did some stuff to it today and it sounds awesome!! I switched 47k NFB resistor wire from jack to 8 ohm tap, I put a Tung sol in V1 and Mullards in V2,V3,V4,V5 and biased them a little hotter and WOW!! haven't tried the Panasonic cap on V1b yet I think I am going to leave it for a while and let the Sozo's settle in and go from there.

Thanks everyone for your info!!

Turd