Moderators: pompeiisneaks, Colossal
I always hear these values increasing as more compressed and less concussive . Less fundamental punch and more upper harmonic content . I find it easier to play in a band the closer I get to those plain Jane stock low plate . I betcha this is a nice pairing with that music man el34 output, just a lil bit of give to dampen the midrange clarityjelle wrote: ↑Tue Oct 31, 2023 2:31 pm Thanks guys!
Plate cathode values are a bit different and the amp sounds great. It sounds very similar to 100K/1.5K, I wonder if I could tell which is which if compared to a 100K plate amp.
The chassis: location of boards was way off. I filled many holes with RTV, and put the chassis holes in the correct spots. The tube holes were left alone.
. Those Aerovox Cathode Bypass caps are ancient...I assume you reformed them and checked the ESR? Funny thing, for some reason I find many ancient electrolytic capacitors to reform to perfection and have low ESR assuming they are low voltage and low capacitance. The physically larger electrolytics (Capacitance & Voltage) obviously tend to be problematic if they are older. Like you, I don't waste my time trying to reform and use them...every time I do, they end up not doing their jobs very well. .GPD,GPD wrote: ↑Tue Oct 31, 2023 11:21 pm Jelle,
A very sexy build...I love the combination of the uber-rare NOS parts you are using. The 121K Plates coupled with the 1.69K Cathode resistors a good strategy given the scarceness of the usual suspect values here. For me, I'd run 1.82K on the Cathodes but 1.69K is surely close enough and you obviously had some 1.69K's of the right vintage of Electra's and IRC MEB's to handle the grid leak chores
I can also see you are using some sort of black thread locking compound similar to what HAD did back in the day. I noticed on some of his builds he was using "Corona Dope" as a thread locker...it has that telltale brownish or reddish hue to it. He used this to prevent arcing in some of his higher B+ builds...particularly some of the really early oddball, 1-off builds I've seen of his. A nice touch...besides, nobody really wants any of that hardware to come loose!
The white teflon jacketed teflon coax...RG188A/U? The lone MK3 Slope resistor married with the Dale's and those elusive LCA0411 Draloric's...all the period correct goodies...has to be a great sounding amp. Love the tidy lead dress and super soldering as well. Kudos! Very exceptional build quality...though that's sort of your calling card anyway.
I do like the sound of the power section with EL34's when you run the B+ up high (700+VDC) and then the screens down a bit lower so the tubes survive...its a big, round and bold sounding amp for certain. Very different compared to the B+ in the typical 450VDC of many ODS's. The bypass cap values are surely adding to the beefiness this amp should deliver. And all those NOS 6PS caps are well worth the trouble you put into sourcing them
Have any clips of it yet?
I hope it sounds as good as it looks