EF86 needs more drive?

[tubeswell]

My line of thinking was that if Joe rolls off a bit of bass out of the 1st stage with smaller Ck there, then you may not need to change the bypass cap on the subsequent EF86 stage as much (in fact it may be 'better' to leave it at 10-25uF). But try it and see. (It also depends on what size speakers you are running the amp through)

[JoeK]

I'm playing the amp through my 1 by 12 ported AX84 cab and it is a big sounding box compared to an open back combo etc so I think there will be more bass frequency but I've used the cab for deluxe and 18 watt builds for a few years now. I reduced the cathode bypass on the first stage to 2.2uf which helped a bit but I tried finding a sweet spot for a "sparkley" clean sound with the bridge pickup on my strat and I've still got the bass and mid on 1, treble on 8 and I'm rolling off the bass on my strat! So I might try some different cap values today. I've also been mucking around with voltages on the plate and screen and at the moment I've got 50K on the plate and 660K on the screen, the B+ is 235 at the node and I get 170VDC on the plate and 73VDC on the screen, been trying to work out the load lines ever since to see if the screen is dissipating too much The other issue I had with the amount of gain coming out of this EF86 stage compared to the other channel has been tempered with a 470K/470K voltage divider after the EF86 and before the 1M master volume so obviously I'm dumping half the output of the EF86 before it gets to the master. At the moment if I'm trying to get the EF86 into distortion I can lift the tone stack slightly to get more signal hitting the input and put the master volume on 1-2 and go from clean to grind with the guitar volume. I did a quick recording yesterday but I'm not good at playing or recording, what do people do when they need to attach an mp3?. Like building tube amps though. Think I worked out the mp3 EF86 1.mp3

[imaradiostar]

OK, just because I'm annoying and curious- wire the tone stack after the pentode and a single 500k pot and 5nf cap between the triode and the tone stack. Make sure there is a volume after the tone stack. I think it'll really get you where you want to go! It'll allow you to smack the pentode really hard then turn things down and mess with the tone after the pentode.

jamie

[JoeK]

OK, just because I'm annoying and curious- wire the tone stack after the pentode and a single 500k pot and 5nf cap between the triode and the tone stack. Make sure there is a volume after the tone stack. I think it'll really get you where you want to go! It'll allow you to smack the pentode really hard then turn things down and mess with the tone after the pentode.

jamie

OK as it's amp day and as my test amp is already like a spider web of 20 guage teflon I might just try it.

[JoeK]

Here is a schem of the amp as per my last post. Grrr forgot to add the 1m pot on the bottom of the tonestack to lift the TS "Raw" As this pot is parallel with the Volume pot it reads 500K to gnd.