My X10 has begun

[pamaz67]

Hey Surf, What's going on with your amp?
They say No news, good news........

Paolo

[surfsup]

I was in florida working all week got back late friday. I didnt stop near the office to check and see if my mouser delivery was there. I'll start again tomorrow prob. First step is get the voltages in line.

[surfsup]

Okay so I swapped the 1k5W for 680R5W and that got me 300, so extrapolating the line, I have two 330R 5W ohmites in there now. The voltages at the plate/OT are 342 dropped and rectified (a touch high, two 400R5W would be perfect):

AC standby off: 333/441
C1: 343
B1: 339
B2: 336
B3: 324
B4: 307
B5: 293

Since I have the VVR, I just turned it down to read 330 on the plates/OT.

I also swapped in a 0.0022 (223J) orange drop cap on the V1a coupling. Bass attenuation is much better. This amp is starting to really deliver. Rolling the guitar back to about 5-6 really cleans it up nicely without much loss in volume.

[surfsup]

So I swapped the cathodes on V1 as Paolo did earlier. It seems to "tame" the amp slightly. I think I will switch them back.

Observations:
1) overdrive still a tad bassy I *think*, this is with the neck pickup on a LP with AlnicoII HBs.
2) Gain pot at V1 is maxxed out at 30%, turning it more doesn't get louder.
3) bass pot still limited range as well at 20%
4) treble pot useful range about 50%
5) My tone pots are wired backwards, that might affect 2-4
6) VVR "works" across 0-10 but while turning it through from about 5-7 it sounds like a radio is feeding back into it. If I leave it at a setting between 5-7 there is a lot of crackle. I really like the VVR on the lower settings, really nice to have that with the MV so I want to keep it and figure this out.
7) Gretsch single coil w/Dynasonics sounds a tad thin (this was after the cathode switch)

[Colossal]

5) My tone pots are wired backwards, that might affect 2-4

Surfsup, if there is a problem with the labeling in the schematic that might have led you to mis-wire the pot, I apologize. Great to hear you are getting close to dialing the amp in.

[surfsup]

No, I'm afraid to say its just tone stacks confuse the s&#t outta me.

[Colossal]

No, I'm afraid to say its just tone stacks confuse the s&#t outta me.

Hahaha, dude don't feel bad; it's easy to make a mistake! I label the legs and wipers according to 1, 2 (wiper), 3 and double check the schematic before I solder. It's easy to make an error if distracted or if soldering in the wee hours and short on sleep.

[surfsup]

I think I've only worked on soldering a half dozen times before 10pm, thru midnight easy. Considering I'm at work at 5am that's wee hours for me!

[rhinson]

So I swapped the cathodes on V1 as Paolo did earlier. It seems to "tame" the amp slightly. I think I will switch them back.

Observations:
1) overdrive still a tad bassy I *think*, this is with the neck pickup on a LP with AlnicoII HBs.
2) Gain pot at V1 is maxxed out at 30%, turning it more doesn't get louder.
3) bass pot still limited range as well at 20%
4) treble pot useful range about 50%
5) My tone pots are wired backwards, that might affect 2-4
6) VVR "works" across 0-10 but while turning it through from about 5-7 it sounds like a radio is feeding back into it. If I leave it at a setting between 5-7 there is a lot of crackle. I really like the VVR on the lower settings, really nice to have that with the MV so I want to keep it and figure this out.
7) Gretsch single coil w/Dynasonics sounds a tad thin (this was after the cathode switch)

i just finished my build (no vvr) and experienced pretty much the same voltage situation that you have been documenting with the 2 1k's in the hv ac line------my idle dcv was about 260v or so on the plates if i remember correctly (my power trannie is a heyboer ac15 vintage clone that is around 326-0-326 nl and gives around 445vdc nl.) . so i'm gonna either lower my 1k's or use a 6ca4 rect. (i punched a hole just in case). i want about 300 -310vdc idle on the plates on my build.

the tone stack works fine and is bassy---this is normal for what this is. that's why i used a 1500pf first coupler and added a toggle for a parallel 8200pf cap----to get close to the .01uf that seems to be in one of the pics. i'm testing thru a 2-12, it make a diff. the .01 may be ok thru a single 12 greenback/blue like they come stock with. also a 3-way brite sw. with 100pf-off-180pf-----only way to go! my personal belief is the master is a dual 1ma with 1meg resistors on the outer lugs. --all in parallel with the 220k's. i only had a dual 500ka so i'm sticking with that for now---standard audio taper feel is not as good for this without the resistors on the outer lugs imo.
another way to add brightness back is to bypass the 470k into the 2nd stage with a cap (like the 470pf in a marshall for instance). rh

[surfsup]

Rhinson, that was quick! Geez...

You'll prob want a value near 620R 5W on the AC lines. 680 for me put my OT/plates at 300 with 122ac supply 300/300 pt.

How does your 1m vol on v1 work? Do you get a change through full rotation? I think this should be 500k pot not 1m. Colossal gave me an idea to parallel a 1m on the pot to lower its value. I need to change my bright switch caps (50/100 now) to higher values too.

[rhinson]

Rhinson, that was quick! Geez...

You'll prob want a value near 620R 5W on the AC lines. 680 for me put my OT/plates at 300 with 122ac supply 300/300 pt.

How does your 1m vol on v1 work? Do you get a change through full rotation? I think this should be 500k pot not 1m. Colossal gave me an idea to parallel a 1m on the pot to lower its value. I need to change my bright switch caps (50/100 now) to higher values too.

mine is actually a 500ka. i haven't had a chance to "dog it out" yet---that'll come later this week. the lower value pot helps slightly to bleed a little more highs (just like in guitar pots). i also used the 12ax7 in the 3rd stage with a 220k/56k divider on the input grid. also a cut pot instead of the set network. rh

[pamaz67]

So I swapped the cathodes on V1 as Paolo did earlier. It seems to "tame" the amp slightly. I think I will switch them back.

Observations:
1) overdrive still a tad bassy I *think*, this is with the neck pickup on a LP with AlnicoII HBs.
2) Gain pot at V1 is maxxed out at 30%, turning it more doesn't get louder.
3) bass pot still limited range as well at 20%
4) treble pot useful range about 50%
5) My tone pots are wired backwards, that might affect 2-4
6) VVR "works" across 0-10 but while turning it through from about 5-7 it sounds like a radio is feeding back into it. If I leave it at a setting between 5-7 there is a lot of crackle. I really like the VVR on the lower settings, really nice to have that with the MV so I want to keep it and figure this out.
7) Gretsch single coil w/Dynasonics sounds a tad thin (this was after the cathode switch)

Hi Surfsup and Rhinson.

1) I agree . also in mine it's like that
2) I 'm using the famous grid bleeding res, and it's working really well, with all the pot run that offers a wide variation of sounds spanning from clean to heavy OD. Surfs, you can switch that resistor in and out with one of your switched pot, and that could be nice IMHO.
3) My bass pot has a useful range of about 40% of the total run.
4) Same as above.
5) If they are wired backwards is just because they are wired as the vox pots.


Edit: I replaced the 10nF coupling cap after the first tube , with a 1nF cap and it's much more usable. The bass pot now , when the amp is used on clean sounds works on 100% of its rotation. Much much better.
The bright cap in mine works very well and it's really usable , giving two different flavours to the all amp, especially in the distorted sounds.

[surfsup]

2) I 'm using the famous grid bleeding res, and it's working really well, with all the pot run that offers a wide variation of sounds spanning from clean to heavy OD.

I am too, but a 100k. I need to change that. I might see if I could get a pot in there temporarily, then find a setting that works good for HB and SC and use the pushpull to set each depending on the guitar.

I probably should look into the RC filter on the PI as well. Maybe lower the R value a bit and raise the (f) a bit.

Edit: I replaced the 10nF coupling cap after the first tube , with a 1nF cap and it's much more usable.

I put in a 2n, I might leave that for a bit but I do have a 1n I can use.

The bright cap in mine works very well and it's really usable

What bright cap value?

[pamaz67]

What bright cap value?

standard 100pF. It's more than enough for me. I'm using a polistyrene over there

[surfsup]

Ive got a 100 and 250pf on my switch, working well. Also swapped the 100k gridleak with a 56k per original scematic and put a 47k on my pp pot switch to switch in series or bypass for 56/103k option w the 220k. Seems to work well. The slope switch still functions well also with the three options. I also changed the cathodes on v1 back to the schemo, think its better that way, a little dirtier. Also swapped the CC to stage 2 w a 1n0 and it tamed the bass a touch. Also rewired the tonestack. Everything works now louder to cw. First gain, treb and bass all work now through full rotation.

Was thinking about paralleling a 1m with the pin 1/3 of the first gain pot to in effect have a 500 there but now that pot works thru full rotation...? Maybe the tonestack being reversed had something to do with it.

Everything coming together. Still a "touch" blatty on the bass or when two strings are ringing together. Vvr still has a mid-zone of rotation that sounds like some sort of short to ground when the pot is btwn 5-7.

Amp if very quiet, not much static and no hum.