I built them, probably like most, specifically because they had light blubs in them lol. But it just felt like a spot light on my face because they are just so bright and that was too distracting while listening. What a great conversation piece though!
I am may be having a problem though, but it could just be the way I am measuring. When I measure from the neg on the output cap to ground, I am getting 11-12vDC. It even happens when I have the caps hooked up to the DIYStore speaker protection board, which should close the output relays upon detection of DC. This makes me think my ground has DC on it and the problem is the way I am measuring it.
I am may be having a problem though, but it could just be the way I am measuring. When I measure from the neg on the output cap to ground, I am getting 11-12vDC. It even happens when I have the caps hooked up to the DIYStore speaker protection board, which should close the output relays upon detection of DC. This makes me think my ground has DC on it and the problem is the way I am measuring it.
I recall the presentation at BAF where I wired it together on stage and
announced, "If it doesn't work, let's hope it at least catches fire."
When it lit up and the music came on I got the biggest reaction from any
audience ever....
I have some inventory of those bulbs and such, and have been playing
with the big SITs with them, just for kicks.

A little off topic, but the ZenLite amp http://www.firstwatt.com/pdf/art_zv1.pdf was the first power amp I ever built and it's still one of the coolest builds I did thus far.
Light bulb loads simply rule.
Light bulb loads simply rule.
Attachments
..... been playing
with the big SITs with them, just for kicks.
![]()
be careful, pitch's and forks....... you can't confess having fun and free time, while Greedy Boyz are eagerly waiting for fix

I recall the presentation at BAF where I wired it together on stage and
announced, "If it doesn't work, let's hope it at least catches fire."
When it lit up and the music came on I got the biggest reaction from any
audience ever....
I have some inventory of those bulbs and such, and have been playing
with the big SITs with them, just for kicks.
![]()
"If it doesn't work, let's hope it at least catches fire." That’s just too good 😀.
Which big SITs have you tried so far in this topology? I have been planing a De-lite project with some 2sk182es. Can’t wait to hear the sound coming out of this simple amp!
I have some inventory of those bulbs and such, and have been playing
with the big SITs with them, just for kicks.
![]()
You know how much I love those light bulb amps. Post some big SIT porn please. 🙂
Which big SITs have you tried so far in this topology?
All of them in a preliminary survey. I will be going back to that shortly
to refine the circuit.
I will be going back to that shortly
to refine the circuit.
Great!!

Germanium 2SB206 and this amplifier become the " DeLite-Antique" version in the spirit of the early semiconductor pioneersI will be going back to that shortly to refine the circuit.
First Electric Bulbs by Thomas Edison

Well I figured out my DC measuring problem - needed to have a load on the outputs for it to work properly/measure properly. However, running PS at 80v I cannot bias the 6N50D2s at 25v. One channel will go to 26, but running the potentiometer wide open the other channel tops out at 23v. The source pin of both channels is 1.5v.
I have it running right now with the B1 Korg and 90db sensitive 3ways and man it sounds good. It's even quieter than my other kit amp, the Akitika GT101. I do have a 5mH inductor in between the power supply caps and snubber caps on the bridge. I can't hear anything with my ear against the speaker. And this setup has a whole other level of tone color and humanness compared to the chip amp I was using. Going to spend the rest of the night listening to my music all over again 😀
I have it running right now with the B1 Korg and 90db sensitive 3ways and man it sounds good. It's even quieter than my other kit amp, the Akitika GT101. I do have a 5mH inductor in between the power supply caps and snubber caps on the bridge. I can't hear anything with my ear against the speaker. And this setup has a whole other level of tone color and humanness compared to the chip amp I was using. Going to spend the rest of the night listening to my music all over again 😀
Listening to harder stuff like Halestorm you can tell the bass isn't the same as my chip amp - not as deep or as powerful. The treble is a touch soft too, but I knew that going in with this design. The midrange is beautiful and resolving(as it is supposed to be with this unit), and you can clearly hear the difference between music created on a computer vs real people playing in the studio. One of these days I will get some horn speakers hooked up to this DeLite amp, but sooner I will have some Tang Band Metronome's to play with (93db sensitive and no crossover). I am so glad I can enjoy these now - took me years to get around to finishing them.
A new De-Lite is born!
Reading this thread was exactly what i needed to get me out of my lack of building slump! I LOVE the "FRANKENSTEIN" chunckyness of these parts. I am currently waiting on a second set of capacitors, bridge rectifier, and 1 0hm power resistor to make a second discrete leg of the power supply. My transformer is a dual 75V secondary currently paralelled. When I tested a single Channel the sound was amazing with just the 300 watt bulb. However, the sound is a bit harsh with 2 channels. Adding the 200watt bulb in paralell removed the harshness but also removed some of the vividness the single channel had. With the single 300 watt bulb I am unable to get 25Volts at the drain; 23ish is all i can get. With the addition of the 200 watt bulb I can easily adjust the drain to whatever I like but 25 Volts definetly sounds best. In other news its been a 100 degrees for the last few days here in the East Bay of sunny California and this is not the best "summer amp build". Its a bit cooler today and De-Lite is warm but not out of control.
Conclusion for the day is this amplifier is DELIGHTFUL in so many ways. Thanks Nelson and all the builders before me for insipiring me! I'm already building my next amp in my head and am seriouly thinking about taking up welding so I can make my own heat sinks.
Thanks to George "audiorasp" for his genorsity!
Reading this thread was exactly what i needed to get me out of my lack of building slump! I LOVE the "FRANKENSTEIN" chunckyness of these parts. I am currently waiting on a second set of capacitors, bridge rectifier, and 1 0hm power resistor to make a second discrete leg of the power supply. My transformer is a dual 75V secondary currently paralelled. When I tested a single Channel the sound was amazing with just the 300 watt bulb. However, the sound is a bit harsh with 2 channels. Adding the 200watt bulb in paralell removed the harshness but also removed some of the vividness the single channel had. With the single 300 watt bulb I am unable to get 25Volts at the drain; 23ish is all i can get. With the addition of the 200 watt bulb I can easily adjust the drain to whatever I like but 25 Volts definetly sounds best. In other news its been a 100 degrees for the last few days here in the East Bay of sunny California and this is not the best "summer amp build". Its a bit cooler today and De-Lite is warm but not out of control.
Conclusion for the day is this amplifier is DELIGHTFUL in so many ways. Thanks Nelson and all the builders before me for insipiring me! I'm already building my next amp in my head and am seriouly thinking about taking up welding so I can make my own heat sinks.
Thanks to George "audiorasp" for his genorsity!
Attachments
that's Fugly!

including that funny pre left on the bench and that funny Bose spk left top
(have 2 pairs of these, different era, in Daughter's room ; in fact , she is having Roommates, along with Hafler pre , more than 10yrs now - as core of her kid system)

btw. Sauce is still hot 🙂

including that funny pre left on the bench and that funny Bose spk left top
(have 2 pairs of these, different era, in Daughter's room ; in fact , she is having Roommates, along with Hafler pre , more than 10yrs now - as core of her kid system)

btw. Sauce is still hot 🙂
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