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Mk-IV 1K resistor before the EL-34 pin5.

PostPosted: Mon Oct 12, 2015 1:16 pm
by Stevedel
I built a Dynakitparts Mk-IV to power my Ampeg all tube preamp and Ampeg Classic 15" bass cabinet for my bass guitar. (I didn't need a 300 watt Ampeg tube amp in my "cubbyhole music studio".) When I ordered the Mundorf Silver in Oil coupling capacitors the guy at Sonic Craft indicated that I could change the resistors before the EL-34 pin 5 to Takman low tolerance carbon resistors. This, he said would give a noticeable improvement in sound quality.

At the time I didn't do it. I am now considering another Dynakitparts Mk IV for a stereo pair and am considering the change. Should I do this or just use the metal film resistors that I am going to use in the rest of the circuit.

I am looking for the best performance I can get without changing the PCB.

Thanks, Stevedel

Re: Mk-IV 1K resistor before the EL-34 pin5.

PostPosted: Mon Oct 12, 2015 8:57 pm
by battradio
That depends on if you like the hiss and random pops that old carbon comp resistors give you over quiet metal films .

Re: Mk-IV 1K resistor before the EL-34 pin5.

PostPosted: Mon Oct 12, 2015 10:39 pm
by Stevedel
Both of my amps were built with selected metal film resistors. I thought that pairs of Takman low tolerance, matched carbon films may work well in this specific application. Perhaps, matched pairs of Takman metal film resistors would work better.

Hopefully, someone can help me with their experience. It's not a big deal, but I like to build things the best that I can and move on to other projects. Rolling tubes can be fun but I don't wish to be altering the inside without good reason.

Thanks, battradio, for your input.

Re: Mk-IV 1K resistor before the EL-34 pin5.

PostPosted: Wed Oct 14, 2015 7:30 am
by Stevedel
I received an E-mail from Martin at Sonic Craft who indicated that Takman carbon film resistors is probably what I should use, in that application. I have used metal film in all other applications. I should be referring to them as Takman "precision" carbon film resistors.

Anyhow, I want to thank Sonic Craft for their superior customer service. All of my questions were delt with very quickly via E-mail. Also, I had entered the wrong value for some capacitors and when I realized this and notified them they corrected my mistake very quickly and efficiently.

Thank you Sonic Craft.

Stevedel