Ruidoso Bill
Active Member
Yes, that is how I had it wired before all of this mess.
Kegger/blueglow kt88 project
- Thread starter Tubeglowpio
- Start date
Yes, that is how I had it wired before all of this mess.
Ruidoso Bill
Active Member
Ruidoso Bill
Active Member
I have mechanically reassembled everything, the pin 8 junction should be to the top of the 1st cap along with one of the choke wires. the second choke wire to the B+, the 200uf cap, neg side of this cap to ground.
I am pretty sure the thing will work now but I am to bushed to finish wiring it up, maybe tomorrow.
I sure want to say thanks, I hope not premature to all the fine folks that gave me a hand, I owe you one but you're all much smarter than I to begin with!
Thanks again.
Bill
I am pretty sure the thing will work now but I am to bushed to finish wiring it up, maybe tomorrow.
I sure want to say thanks, I hope not premature to all the fine folks that gave me a hand, I owe you one but you're all much smarter than I to begin with!
Thanks again.
Bill
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Ruidoso Bill
Active Member
Thanks, your post is what got me to looking for a contributing problems, many thanks!
Ruidoso Bill
Active Member
Just a quick update, I got anxious for the new caps and tube so tried an old set, I was showing B+ for the very first time, wow, felt good! With 120 VAC in from the variac I and show 580 VDC on the B+.
I am going to replace the tube and caps and keep them for spares, don't trust possible damage with the arching and fuse blowing.
Thanks again to everyone that helped me out!
Now on to the rest.
I am going to replace the tube and caps and keep them for spares, don't trust possible damage with the arching and fuse blowing.
Thanks again to everyone that helped me out!
Now on to the rest.
Good deal, glad things are working out. I would bet that the tubes and caps are OK and undamaged. You could damage the caps with too much voltage, but as you saw you never got much voltage at all. Tubes are sometimes tougher than you think. If you can run them in the circuit and they're not arcing anymore and the amp's voltages are fine, they're probably good to go. Your fuses all took the hit.
Ruidoso Bill
Active Member
Thanks, I had ordered them when desperate, is it normal for it to hum a little? I at first thought it was my variac but think it the tube.
invaderzim
Super Member
I started with the Alex Gendrano version of this amp and while it was excellent I do have to say the more I implement the Kegger modifications the more it amazes me. I've added the grid leak and grid stopper resistors to the 6AQ8, increased capacitance from 10 to 30 on the capacitor before it, LED bias and negative feedback and the sound just keeps getting better and better. With the way it is sounding now it annoys me that people think of the 'tube sounds' as soft and overly warm since this is really quite detailed.
I am almost to the point where it matches the blueglow build. I just need to change the plate load resistor and add the switch for UL. I'm running 6L6GCs or KT-66s in it right now so I may add a switch to the bias so I can change it over to KT-88s and back easily.
I am almost to the point where it matches the blueglow build. I just need to change the plate load resistor and add the switch for UL. I'm running 6L6GCs or KT-66s in it right now so I may add a switch to the bias so I can change it over to KT-88s and back easily.
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Ruidoso Bill
Active Member
I am going to do some more amplifier wiring today, I really enjoy the building but I must admit getting a little excited to hear it.
invaderzim
Super Member
That is the most difficult part in any build, not rushing towards the end to get to hear it.
It is taking a lot of self control for me to do one upgrade at a time that way if something goes wrong I'll know what did it and I can hear the effect of each change.
Ruidoso Bill
Active Member
invaderzim
Super Member
At least you got the gene for proper wiring layout. That is looking great. Mine always look that way in my mind when I plan it but end up looking like:
Ruidoso Bill
Active Member
At least you got the gene for proper wiring layout. That is looking great. Mine always look that way in my mind when I plan it but end up looking like:
Progress for today:
I ended up making brackets (nothing wrong with drilling more holes) and heat shrunk the Nichicon caps vertical
Finish the Pot and the led bias stuff and done?
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Ruidoso Bill
Active Member
Pretty darn exciting day for my build. I went through my wiring versus schematic three times, got the nerve to start bringing the amp up with the variac on a dummy load with a 1 khz tone feeding both channels, no smoke!
Actually hooked one of my speakers up and could hear the tone, brought it back down and moved the speaker over to the other channel and again heard the tone starting around 70 vac in.
Everything back on dummy load, checking the B+:
100 vac in = B+ 323 vdc
110 vac in = B+ 383 vdc
115 vac in = B+ 410 vdc
120 vac in = B+ 444 vdc
So exciting, sound out of both channels, tomorrow it gets the work out into dummy load, check it with my osciliscope.
Super rewarding feeling, haven't built from scratch for nearly 50 years, the dynaco rebuilds don't even come close!
Got to share that excitement when the tubes start warming up, and you hear the tone, Mark Walker shared, pretty cool!
Actually hooked one of my speakers up and could hear the tone, brought it back down and moved the speaker over to the other channel and again heard the tone starting around 70 vac in.
Everything back on dummy load, checking the B+:
100 vac in = B+ 323 vdc
110 vac in = B+ 383 vdc
115 vac in = B+ 410 vdc
120 vac in = B+ 444 vdc
So exciting, sound out of both channels, tomorrow it gets the work out into dummy load, check it with my osciliscope.
Super rewarding feeling, haven't built from scratch for nearly 50 years, the dynaco rebuilds don't even come close!
Got to share that excitement when the tubes start warming up, and you hear the tone, Mark Walker shared, pretty cool!
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Ruidoso Bill
Active Member
Spoke too soon!
I am blowing the fuse and the top of the KT88 one is glowing brighter than the other. Still the tone, still good B+. As you can see the tube on the right is brighter
This fuse issue started when I turned the amp upright, makes me wonder if I have another pinched wire.
I am blowing the fuse and the top of the KT88 one is glowing brighter than the other. Still the tone, still good B+. As you can see the tube on the right is brighter
This fuse issue started when I turned the amp upright, makes me wonder if I have another pinched wire.
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I built this amp once (stereo) then sold it. After experimenting with several other amps since then (6BQ5 SE) & considering a DHT, I’ve decided to build another. Only this time, more simplified in the mode I preferred. For starters, no bias switch, triode only, EL-34, 15 watt GXSE OPT.
I’m really interested in the mono-bloc & separate PS discussion. I think both ideas would take this amp beyond ultimate.
I’m gonna enjoy following this thread!
invaderzim
Super Member
That is a bummer. The nice thing with clean wiring is it is easy to trace where they all go but hard to do with it right side up. Most likely a heater wire since one is glowing that much differently? It is a completely uninformed guess though.
JohnT123
Super Member
This is my version of the amp in discussion. I like working with Aluminium and the Blueglow build vids got me excited to build my first hi-fi amp. I've been doing guitar amps for more than 20 years but always thought my chops weren't good enough for "serious audio" work. Marks video series just pushed me over the edge. I'm officially down the rabbit hole.
I should add that the chassis and transformers were purchased years ago to built a stereo version of a VOX AC30 for a guy. He bailed on the project and stiffed me. Funny how it all worked out..
Ruidoso Bill
Active Member
That is one super neat assembly, I try hard but can't come close to that, what a great job!
Ruidoso Bill
Active Member
Well, I resoldered every connection last night, blew the fuse when I hit it with straight ac out of the outlet, I guess the variac nurseses it.
I decided to try to isolate (Divide & Conquer) it so disconnected the B+ to the amp side, no blown fuses, connected the B+ without the OPT's hooked up, still no blown fuses. Connected the Right channel, no blown fuse and got my tone. Connected the left channel and zap, lost a fuse. I now know where to look.
My wife is commenting how much more patience I am learning, sigh
I decided to try to isolate (Divide & Conquer) it so disconnected the B+ to the amp side, no blown fuses, connected the B+ without the OPT's hooked up, still no blown fuses. Connected the Right channel, no blown fuse and got my tone. Connected the left channel and zap, lost a fuse. I now know where to look.
My wife is commenting how much more patience I am learning, sigh
