Looks like fun. A Voxy Pee Wee! :icon_biggrin:Awwww..now you tell me.
Checked the price of 6GW8s yet? :huh:
Hey boys! Happy New Year! SG great minds think alike.HNY, old timer! Yeah, we must be drinkin' the same KoolAid.
I'm torn.Creed?? :wink:
SG, those Hammond 6GW8 are quite likely Mullards, i have seen GE & RCA 6GW8 with made in markings of, Holland, Gt. Btn, & W. Germany.Cool, I'll snap a couple pics you can tell me if I've got the good stuff. I've never spent much time thinking about old type brands. I was a late bloomer with little money....not a good combo.
the Hammonds sounded best to me, however, still too EL84-ish sounding, so I passed. i have some of that AO-44 iron that i still haven't a clue what to do with... perhaps another 6005/6AQ5 amp?So maybe this is the destiny of the 6GW8? A poor mans single channel AC?
SG, voxy cops are watching your vox violations and such shenanigans. you have 24hrs to change cathodyne PI to LT, or else! you have been warned! :pI ain't scared. I'm all stocked up on ammo, whiskey, anti-inflammatories, capacitors, and bulk bridge rectifiers. They can't hurt me.
Did I see a crack in the 1K Carbon Comp resistor (PS Node A to Node B).Nice catch, I'll keep an eye on that.
If that resistor is cracked, check for shorts on the cap can too.I was gonna ask you about that cap. I've never messed with re-using old parts.
And before you start ripping things out, connect a power cord and check for proper AC voltages on the rectifier socket. If good, plug in ***ONLY*** the recto tube and check for proper B+ voltages. Even better, if you have a variac, use it to slowly bring up the primary voltage to 120 over a few hours. You may get lucky and be able to use the original cap can. I was lucky. In fact, I havent found a single can to be defective in the few Hammonds I've played with.
Yup, it's cracked and only reads 274 ohms. The other 2 are good @ 5.7k and 9.8k.Did I see a crack in the 1K Carbon Comp resistor (PS Node A to Node B).Nice catch, I'll keep an eye on that.
if you are open to suggestions... easy enough to add & remove if you don't like. helps immensely with cathodyne doubling distortion.That looks good. Should I consider bypassing it with a cap to retain highs?
--pete
I built one of Sluckey's Voxy Pee Wees over the summer, great amp.Haha. I had already forgotten about that! Sho nuff. I have the Visio file in my Pee Wee folder. SG should save your modified schematic. Could be something there that he needs/wants.
Done deal. I'm a schematic hoarder. I'm gonna start out super simple and then see if it needs anything. I've learned that less options is better options for me.I built one of Sluckey's Voxy Pee Wees over the summer, great amp.Haha. I had already forgotten about that! Sho nuff. I have the Visio file in my Pee Wee folder. SG should save your modified schematic. Could be something there that he needs/wants.
if you are open to suggestions... easy enough to add & remove if you don't like. helps immensely with cathodyne doubling distortion.That looks good. Should I consider bypassing it with a cap to retain highs?
--pete
I want it to sound exactly like a cranked Major through a full stack, so whatever I have to do to get there.
I trust you.
jim bob is gonna ...still. not. scared.
But I've got a couple questions:1. Look closely at the AO-44 schematic. What do you see? http://sluckeyamps.com/PeeWee/PeeWee.pdf
1) I don't see a center tap for the filament winding in my amp or the pics of sluckey's. Where is it?
2) Whats the best way to run the cap(s) at low voltage since I need to feed the rectifier filaments for it to light up?..I'm guessing I should just jump a couple diodes over for now?
Hey boys! Happy New Year! SG great minds think alike.HNY, old timer! Yeah, we must be drinkin' the same KoolAid.
I was gonna turn this into a Mini Micro Major, but we all know Majors suck so I decided to go down this already mostly paved path.
I'm thinkin I'm gonna call this one The Drama Queen after one of our long lost friends who so tragically lost his way over the last few years with the emergence of modeling technology, the acquisition of cheap overseas guitars, and just flat out fake news. An alternative name for the amp would be The Melted Snowflake. I'm torn.
I usually spend wayyyy too much time trying to make everything look perfect so I can never take pictures and then not post anything anyway.
It will be a joy to throw a couple parts at this and see where it lands. In the process I'll try to snap some pics and maybe even play a couple riffs through it.
As long as nobody hurts my feelings I'll stick around. :rolleyes:
Thanks Pete, I have to remember that grid stopper trick. I think Merlin describes that a high value doesn't mess with the high end correct? It's very late for me and I have no time to look up the exact reason why?if you are open to suggestions... easy enough to add & remove if you don't like. helps immensely with cathodyne doubling distortion.That looks good. Should I consider bypassing it with a cap to retain highs?
--pete
I want it to sound exactly like a cranked Major through a full stack, so whatever I have to do to get there.
I trust you.
yes, switchable would be cool to have clean-ish option as well.
jim bob is gonna hunt you down for even comparing to a Major. :icon_biggrin:
Thanks Pete, I have to remember that grid stopper trick. I think Merlin describes that a high value doesn't mess with the high end correct? It's very late for me and I have no time to look up the exact reason why?if you are open to suggestions... easy enough to add & remove if you don't like. helps immensely with cathodyne doubling distortion.That looks good. Should I consider bypassing it with a cap to retain highs?
--pete
I want it to sound exactly like a cranked Major through a full stack, so whatever I have to do to get there.
I trust you.
yes, switchable would be cool to have clean-ish option as well.
jim bob is gonna hunt you down for even comparing to a Major. :icon_biggrin:
SG - I've build the CAT pi w/ ECL86s and I had to lower the load resistors down to 56k to lessen the output. BUT, if I'd added that grid stopper maybe I could've left them at 100k like your schematic? Pete please confirm if possible? Thanks brother
SG, those Hammond 6GW8 are quite likely Mullards, i have seen GE & RCA 6GW8 with made in markings of, Holland, Gt. Btn, & W. Germany.Here's some pics
so how many of those cute tubes fit inside a KT88 :icon_biggrin:17?
17? As in the letter Q??? :icon_biggrin:so how many of those cute tubes fit inside a KT88 :icon_biggrin:17?
Blasphemy! Boy-Drama says...there's nothing that can replace or sound as good as KT88s, NOTHING! I say, "what did you say?" Who can hear anything after actually playing KT88s???
...sandwich TS inside of the NFB loop for that major major tone. oh wait, this is a żżvox?? now i'm confused. oh hell, just insert TS in front of cathodyne & ditch NFB and viola! Major Vox? meh! peace out!
--pete
SG, those Hammond 6GW8 are quite likely Mullards, i have seen GE & RCA 6GW8 with made in markings of, Holland, Gt. Btn, & W. Germany.
Here's some pics
So there was sound. I have a nice sweet chime up til about 3 on the volume and then it starts getting unruly. I don't think I ever got it up to 10 because it was just a screeching little bees nest of distortion and oscillation, before I could even get my guitar volume up.
:l2: The only thing missing was the FIREQuoteSo there was sound. I have a nice sweet chime up til about 3 on the volume and then it starts getting unruly. I don't think I ever got it up to 10 because it was just a screeching little bees nest of distortion and oscillation, before I could even get my guitar volume up.
oh, so what you're really saying is that it sounds just like a major? :icon_biggrin:
--pete
You shouldn't need the voltage dividers in there after the pi coupling caps if you lowered the 100ks to 56ks... Just saying. And no power tube cathode bypass cap?! Sacrilege... If it were me I'd throw in a simple crossline MV... but I always mod the pot filing away the uppermost trace. When full up it's out of circuit without a switch. A nice little feature having it your way just like Burger queen.I did put the voltage divider after the PI and it worked like I wanted. I put some bypass caps across the series resistors and it made a noticeable improvement.
FIRE isn't what it used to be... you can find it being applied to old glory nightly in about any major US city near you... :sad2:
fender 112K cathodyne load line would swing less, 94K even less. shoot for about 1.2mA Ib at 270V B+ with either. however, with the fender or hammond plan, the output swing will still be pushed though a stage with a gain of 1 - limiting the drive swing from the preceding stage would make more sense. one way would be to split the anode R of the cathodyne driver and requires just 1 part.I read right through this initially.
I read right through this initially.:laugh:
Then one where there's an '86 into another '86... this is plain evil... >:)
You may want to add 1N4007 diode protection in for each 6CA4 anode, just in case the 6CA4 is getting old.I updated the schematic to reflect the voltages and added those diodes (thanks, I like insurance)
Have the EF86 and the triode anode voltages all idle biased up ok? One pain with the 6GW8 (and any triode pentode) in a PP arrangement is that not only do the two output stage pentodes need to have reasonable idle current balance, but the two triodes need to sit their anodes at reasonable idle levels, otherwise the signal can start to get wacky too early.
So, it appears that my pre PI voltage divider was also dividing the voltage at the PI cathode. I'll insert a cap right after the divider and re-measure. Unfortunately I'll have to wait til later.Bingo! The cap will fix that.
I confirmed this by snipping out the the V div. path to ground and now I'm seeing 44VDC on the PI cathode.