kodabmx said:
I'm finding the difference between the 20D2 and 50D2 to to be subtle but noticable. They both sound great. To my ears the 20D2 has a slightly more natural presentation. Mids are clearer, Bass a more distinct, the highs a bit less airy. There may be some hF roll-off but fortunately my aged ears can't detect it.
Jeffrey
Blew another MOSFET on a transient. Added diode strings for the input.
Never "blown" a tube on a damned transient!
Here's the thread 😛 6P45S PPP Monoblocks.
TL;DR: They make 110W RMS @ 30Hz and sound just great IMHO.
EDIT: I've now tried 500W bulbs instead of the 300W and it seems to have increased the output (light AND sound)!
Never "blown" a tube on a damned transient!
Here's the thread 😛 6P45S PPP Monoblocks.
TL;DR: They make 110W RMS @ 30Hz and sound just great IMHO.
EDIT: I've now tried 500W bulbs instead of the 300W and it seems to have increased the output (light AND sound)!
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Another update in case anyone is interested... with 300W bulbs and the MOSFETs biased for 27V across them, the heatsink is 65c...
With the 500W bulbs in place but the same 27V across the MOSFETs, the heatsink is 80c! When it blows up, I'll know why LOL
With the 500W bulbs in place but the same 27V across the MOSFETs, the heatsink is 80c! When it blows up, I'll know why LOL
One more followup I Guess...
I've added a fan. Using the 500W bulbs now.
I know it's come a LONG way from the simple de-lite that Mr Pass came up with, but his goal was to get people to DIY. I've been doing that for years with tubes, but never solid state. It's always basically been witchcraft to me how they work, and they aren't nearly as robust as a tube save for throwing it on the floor, but Nelson's original amp made me finally tinker with transistors.
It's really amazing how much better it sounds as a source follower though! My next amp idea will probably be a push pull source follower using output transformers! Let's see how these things work and if I can make 50W using 150V B+ for the output MOSFETs (which will be these same IXTH6N50D2 I think without blowing too many parts up. My only hinderance is how expensive "thermal management" is compared to tubes! I could build an entire tube amp for the cost of a big chassis with big heatsinks! When this covid thing is dying down, I'll check my surplus spots again.
Oh ya, it takes 400W from the wall, too!"
Koda
I've added a fan. Using the 500W bulbs now.
I know it's come a LONG way from the simple de-lite that Mr Pass came up with, but his goal was to get people to DIY. I've been doing that for years with tubes, but never solid state. It's always basically been witchcraft to me how they work, and they aren't nearly as robust as a tube save for throwing it on the floor, but Nelson's original amp made me finally tinker with transistors.
It's really amazing how much better it sounds as a source follower though! My next amp idea will probably be a push pull source follower using output transformers! Let's see how these things work and if I can make 50W using 150V B+ for the output MOSFETs (which will be these same IXTH6N50D2 I think without blowing too many parts up. My only hinderance is how expensive "thermal management" is compared to tubes! I could build an entire tube amp for the cost of a big chassis with big heatsinks! When this covid thing is dying down, I'll check my surplus spots again.
Oh ya, it takes 400W from the wall, too!"
Koda
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Nice! Has it changed the sound in any way? When it's safe to gather again, will you bring this to the GTA meet (whenever that may be)?
how is the damping factor with bulbs?
I used a similar setup:
1000W 230V bulbs, 19Vpsu 1A bias the bass was mudd
I used a similar setup:
1000W 230V bulbs, 19Vpsu 1A bias the bass was mudd
It's not bad at all since I'm running the MOSFET as a source follower. II switched back to 300W bulbs because I could smell the damned thing. The heatsink was 104°C when I turned off lol
I have a small update?
I found my old Lawry 6V6 tubes and swapped them in in place of the 6P3S. I also swapped the 6N8S for RCA 6SN7 that happen to have black plates and a date code from 1957 🙂 So what? LOL
It's the perfect combo of old meets new IMHO.
The output MOSFETS are now IXTH6N50D2.
I found my old Lawry 6V6 tubes and swapped them in in place of the 6P3S. I also swapped the 6N8S for RCA 6SN7 that happen to have black plates and a date code from 1957 🙂 So what? LOL
It's the perfect combo of old meets new IMHO.
The output MOSFETS are now IXTH6N50D2.
I'va been thinking about three legged critters again. The lone ones. You know which ones. Zen. Why? Becuse, when you feel lost in the woods, you make a large circe and after a while, found yourself at the point of depart. Which, in my case (and maybe your is): ONE (three legged) active device, one fullrange speaker (ok, two - stereo).
Just when we think that everything has already been said, done, built... There is that worm in the back of the head which unsuspectedly pops out
and says : wait, have you tried... And so it goes.
So, I was thinking the following:
De-lite is the great amp for my needs (Fullrange in the OB/sort of). And I like the lighbulbs (I had built an F2-lite before and I liked it).
Now, the solution should be simple: Just go ahead and build the De-lite. But, there's a problem, and I think some other diy-ers may share it: Filter capacitors. Done properly, I would prefer a 80-100 V supply, and some 100.000uF of capacitance. That means a lot of $$...
Instead, I have an empty pocket, an inductor and 19V switcher PSU.
So, I was wondering:
Can De-lite be built with an
IXTH6N50D2 part, but with an inductor and a 19V switcher PSU?
I know that we will end up close to a Zenductor, but... not quite.
Did anybody try this? Nelson maybe? Would it sound better than a Zenductor?
Just when we think that everything has already been said, done, built... There is that worm in the back of the head which unsuspectedly pops out
and says : wait, have you tried... And so it goes.So, I was thinking the following:
De-lite is the great amp for my needs (Fullrange in the OB/sort of). And I like the lighbulbs (I had built an F2-lite before and I liked it).
Now, the solution should be simple: Just go ahead and build the De-lite. But, there's a problem, and I think some other diy-ers may share it: Filter capacitors. Done properly, I would prefer a 80-100 V supply, and some 100.000uF of capacitance. That means a lot of $$...
Instead, I have an empty pocket, an inductor and 19V switcher PSU.
So, I was wondering:
Can De-lite be built with an
IXTH6N50D2 part, but with an inductor and a 19V switcher PSU?
I know that we will end up close to a Zenductor, but... not quite.
Did anybody try this? Nelson maybe? Would it sound better than a Zenductor?
With it hard to find 300w light bulbs perhaps a 250W heat lamp might be a good substitute and a red 250W
heat lamp looks a lot like Nelson's icon !
heat lamp looks a lot like Nelson's icon !
The lamp is not a problem (yet). I had an idea to wire ten 12V lamps im series. The problem is the PSU (hi voltage hi cap valued hi $$ 🙁 )...