Very nice! I would love to hear it in person.....The "tube" on the right was made in the U.S.A.
Are you planning to package it so as to provide safety insulation? The first thing I thought of when I saw your photo was the new packaging for the newest Cree light bulbs that they call Four-flow (I think).
All plastic case with strategically placed ventilation holes so that they get air flow through heat sinks no matter what mounting position.
Thanks Dr Mazzola for the clear image of the "twins". It is clearly a bright idea. I looked up the tech sheet of its power device a while ago, and wrote it is a depletion-mode FET [unlike R100]; but it is not a SIT. This makes sense to use this semiconductor in this application because it is both a depletion type and has pentode-like characteristics like the pentode vac tube. And it will not shatter when accidentally dropped on a hard surface.
Best regards
Best regards
In due time, I hope you'll get your chance to hear it.
Good question about safety insulation. Naturally, we expect to provide electrical safety equivalent to the original tube. We are considering several options, including a plastic envelope with ventilation like you suggested with that image of the Cree bulb. Of course, your favorite "glowing glass bottle" can dissipate way more thermal power than those LED bulbs are rated to pull from the wall plug! I will be seeing Cree friends at the Applied Power Electronics Conference next week. I'll ask them about it.
Good question about safety insulation. Naturally, we expect to provide electrical safety equivalent to the original tube. We are considering several options, including a plastic envelope with ventilation like you suggested with that image of the Cree bulb. Of course, your favorite "glowing glass bottle" can dissipate way more thermal power than those LED bulbs are rated to pull from the wall plug! I will be seeing Cree friends at the Applied Power Electronics Conference next week. I'll ask them about it.
Very nice! I would love to hear it in person.....
Are you planning to package it so as to provide safety insulation? The first thing I thought of when I saw your photo was the new packaging for the newest Cree light bulbs that they call Four-flow (I think).
All plastic case with strategically placed ventilation holes so that they get air flow through heat sinks no matter what mounting position.
The videos were not intended to render an audio comparison but the difference is obvious. On the same video recorded with sale phone , the tubes sound clear and those ss devices do not, they sound grainy, no matter what that guy in the video says...
i listened, and the part that seemed odd to me is that the volume/gain setting of the amp itself seemed altered between the two examples, to the point that its rather obvious that the two sounds are completely different. I'm wondering why the 6L6 amp wasn't compared against a pair of SS devices at the output, particularly when a PP tube amp will make sound with one tube anyway (tho not well or for long). Who would ever use both the tube and SS device simultaneously anyway? That's not a real world example.
Last edited:
I should add too... I'm also a guitar player. My main amp is '68 Ampeg with 5881's converted to use 5U4. A good tube amp acts as an extension of the instrument itself. I know the dynamic 'touch' of an amp, and that twin lacks a lot of touch in with Semisouth, particularly in regard to a clean tone.. simply because you didn't offer it. If it was good.. you'd offer it.
Please find attached [per the teaching of Dr. Mazzola] a simplified output stage of a Fender Twin guitar amp using one 6L6 and a solid state substitute by iMPOWER Systems for the second 6L6. Curious questions for R085 are like those for 6L6:
1. What are its idle and peak currents?
2. Is Vds at its cutoff =~+450V
Best regards.
1. What are its idle and peak currents?
2. Is Vds at its cutoff =~+450V
Best regards.
Attachments
Doctor Mazzola,In due time, I hope you'll get your chance to hear it.
Good question about safety insulation. Naturally, we expect to provide electrical safety equivalent to the original tube. We are considering several options, including a plastic envelope with ventilation like you suggested with that image of the Cree bulb. Of course, your favorite "glowing glass bottle" can dissipate way more thermal power than those LED bulbs are rated to pull from the wall plug! I will be seeing Cree friends at the Applied Power Electronics Conference next week. I'll ask them about it.
Did you learn anything interesting talking to the Cree folks at the Applied Power Electronics Conference? I have long been a fan of their products and have followed the evolution of their replacement LED bulbs with great interest. I have wondered if they use their own SiC mosfets in these A19 bulbs. If so, that could explain the ability of these devices to survive where their competition can't.
Great question!
David Cox, Director of Alliance Development at Cree Lighting, gave one of the plenary speeches at APEC this year. His talk was entitled "Power Architectures for the Next Generation of Solid State Lighting." In his talk he talked about the value of potentially using SiC power devices in various power electronic circuits used in LED lighting. He definitely mentioned Cree SiC MOSFETs, but it was also clear that they don't use them in Cree lighting products at this time. Cost, cost, cost is the hammer that controls everything in white lighting. Some one asked him for the date when Cree would offer a 10 year warranty on their LED products (prompted by his many claims of customer savings due to the long life of the Cree LED lamp). "Not now" was basically his answer.
David Cox, Director of Alliance Development at Cree Lighting, gave one of the plenary speeches at APEC this year. His talk was entitled "Power Architectures for the Next Generation of Solid State Lighting." In his talk he talked about the value of potentially using SiC power devices in various power electronic circuits used in LED lighting. He definitely mentioned Cree SiC MOSFETs, but it was also clear that they don't use them in Cree lighting products at this time. Cost, cost, cost is the hammer that controls everything in white lighting. Some one asked him for the date when Cree would offer a 10 year warranty on their LED products (prompted by his many claims of customer savings due to the long life of the Cree LED lamp). "Not now" was basically his answer.
The "tube" on the right was made in the U.S.A.
I'm glad I bought a pile of those.
I'm glad I bought a pile of those.
Hello Mr. Pass.
I hope this tube replacement is also available for DIYers to buy; preferably as pre-matched pairs or quads.
Best regards
I can think of other things to do with these than plugging into old guitar amps. I'll bet Papa could do some very creative designing if he had a couple to play with. I'm glad I saved those old tube sockets .... They might come in handy for a future Burning Amp project!
Hello poynt99. I did watch the video, and heard a difference in performance. I thought this early prototype was a great idea which can/may be optimized further to excel which I hope it will. Its full potential is yet to come.
I still have about a thousand of the R085's, so a project with them is
feasible. I have to finish some other stuff first...
Thanks Papa. I'm sure that you will come up with an another amazing and ingenious design.I still have about a thousand of the R085's, so a project with them is
feasible. I have to finish some other stuff first...
I was actually thinking of a use for Dr. Mazzola's modules beyond their original purpose. I envisioned a DIY amp that would use the tube replacement devices as output modules that would not need the support of a separate heat sink. I assume they could be used in parallel as they would be in many higher power tube amps. I don't know if that would be practical but I thought it would make for a cool retro design kind of reminiscent of the Zen light bulb amps if the solid state tubes were mounted on top of the chassis.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.