The "$250" Amp? - 6LU8 Compactron SE, UL
- Thread starter Wigwam Jones
- Start date
Wigwam Jones
Caesar non supra grammati
The power section from the amp is prototyped:
More on this later...stand by...
More on this later...stand by...
Tapehead47
Addicted Member
Looking sexy! Finally, something is emerging....
Great stuff, guys. Thanks Wigwam, for the photos. I've started a new folder for this project.
rick
Great stuff, guys. Thanks Wigwam, for the photos. I've started a new folder for this project.
rick
Wigwam Jones
Caesar non supra grammati
Thanks, Rick. Good news, folks, about that transformer. You see that big honking toroidal transformer sitting there? Well, it turns out it's even a better deal than Antec advertised.
You see, this is an Antec 3T275. Here's a link to the specs:
http://www.antekinc.com/trans.html
http://www.antekinc.com/AN-3T275.pdf
Now, in the pdf file you see above, it gives this rating:
I/P 115 V
I/P 115 V
O/P 275 V
O/P 275 V
O/P 6.3V 4 Amp
O/P 12.6 V 3 Amp
But that's not what it is.
It is this:
Notice - no 12.6 V O/P. So Squidward called them up and it turns out that the real specs for this transformer are 6.3 V @ 5 amps and 6.3 V @ 5 amps.
At least, that's what we think at the moment.
Don't rush out and buy the transformer yet - we're testing.
I had a great time at Squidward's house on Sunday. Pakprotector stopped by and we had quite the chat-up. I learned much from both of them (thanks, guys).
When I left Squidward's house on Sunday evening, he was still soldering the heaters up - but he was planning to see tubes glowing by Sunday night.
So that's where we're at. If the story about the transformer is true, it's the best deal ever on a power transformer, and it's about to become their number one best seller.
I will shut up now, share a few more photos, and let Squidward talk.
He did all the work. I took a few notes, took a few photos, and generally got in the way.
We are going with a tube rectifier design - you see one of them sticking out here. But notice - Squidward, Kegger, and Pakprotector (I think it was them, I could be lying accidentally) came up with this awesome idea of wiring in all four sockets you see - they can test a number of tube rectifier designs in the prototype, and go with whatever works the best, be it one tube, two tubes, or what-have-you. So this is for experimentation.
This part is uber-cool. This is Squidward's brainchild. This modular piece will be host to the compactron tubes we're talking about for this design. But, with the awesome modular design of the power section, this amp could support innumerable tube topologies, using any number of different tubes. 300 volts and a bunch of amps for the 6.3 means lots and lots of different choices could be made - and with this modular design plate, you could have fun experimenting to your heart's content.
Here's one more shot of the overall layout. Note that Squidward intends to run the heater power down one side of the chassis, and the tubes to the output transformers down the other side. This should keep spurious noise to an absolute minimum.
I can't wait!
That is looking AWESOME!
Any guess on a tentative timetable for a parts list and final schematic????:scratch2:
That is looking AWESOME!
Any guess on a tentative timetable for a parts list and final schematic????:scratch2:
Wigwam Jones
Caesar non supra grammati
We are still in the early stages, but you've got the right idea. First the prototype - Squidward's going to need some time to test and try and test again until he and Kegger and everyone find something that is livable, makes sense, and doesn't blast the budget.
Then the schematic and parts list, followed by the build, step by step and inch by inch.
The case you see here won't be the final product - that's a pure prototype that Squidward found, and he's really happy with it for prototyping.
One thing we're discovering as we go along is that it is easier to work within a budget constraint, and it forces you to be creative. When you're building your own amp, you use the parts you have, the budget that works for you. But when you have to think about the other guy's pocketbook, and presume that they don't have the workbench full of parts of all kinds that you do, your thought dynamic changes.
Squidward is loving it. He says he's really reaching for a final design that will not only appeal to all the newbies out there who want to build that 'first amp' and have something to really be proud of, but also the ways that things can branch off from there - sky's the limit kind of stuff - but all based around the power section they've designed and the same basic circuit they've come up with. So from mild to wild - this thing will rock. Once all the newbies (like me) have gotten their feet wet with a design that really works and can be built by anyone - and we've done it - then the craziness starts.
One thing that Squidward is wrestling with is the chassis design. It can be a budget-buster, and perhaps not everyone will want to do the same case design. After all, the amp is the amp, whether you stick it to a hunk of plywood or bend up a beautiful aluminum custom case. But we're giving it lots of thought, we'll come up with something, never fear.
Three popcorn thread
Anything worth having is worth waiting for....:thmbsp:
Anything worth having is worth waiting for....:thmbsp:
Here's a few thoughts on the mechanical assembly of the prototype.
The cheap Edcors have exposed solder lugs. They are also not the most beautiful transformer. They are also slightly hefty, which is a good thing, but they requires some space. The cheap Antek is really really out of this world beefy for what it is. It's also no beauty queen. What I'm getting at here is that one might consider under-the-chassis mounting options for both of these transformers. This is primarily why I had to "switch horses in the midst of a stream" (thanks FDR) and ditch the original chassis prototype for the one you see in the pics now. When you under-mount all that iron, you are using up chassis space that you can usually use for other purposes. I commonly mount chokes and caps under top mounted transformers, re-using the bolt holding the transformer to the chassis. Unfortunately, these options disappear when you under-mount. Because of these factors, I would advise anyone building this amp to strongly consider a larger sized chassis. The working area that you see in the picture is 16.5" x 9.5". I divided it evenly with the aluminum angle iron support bar you see in the pic. My chassis is 3" deep, and I believe this will give enough clearance for the iron.
I am recycling a piece of network hardware that I gutted for a chassis. This chassis cost me $5 at a junk shop. It is made of sheet steel, making it easy enough for me to drill out. I have a cheap punch kit for larger holes. I was able to make all of the chassis modifications with the following tools:
Hand drill
Drill bits up to 1/4"
Stepped "unibit" drill bit up to 1"
Punch kit for larger holes (i have a very cheap one from Harbor Freight)
Metal saw (I used an electric jig saw, but someone could use a hand saw)
I build with a lot of 6-32 screw hardware. I buy it by the box from the hardware store. I do a lot of crazy projects, so I have a lot of screw hardware. However, the final build will probably use something standard like some different sizes of 6-32.
If one was comfortable with simple metalworking, a good chassis choice that one could simply buy from the Internet would probably be a Hammond enclosure. Hammond makes an enclosure that is made of aluminum, and is 17x10x3. Radiodaze sells this enclosure for $29. It also is in a size that comes with a cage, if someone wanted that as an option for safety around pets/children. The cage is $45, but it's optional (and some people might really want it).
I guess what I'm thinking is that I might make a drill guide and instruction set that focuses on that Hammond box. Then there would be a standard part that could be included in a BOM, for simplicities sake. I can imagine that many people will deviate and put their amp in widely different enclosures, as well. I believe that the largest stumbling block for this project for many people will be the chassis work required. I can live with the target audience of a build document having no electronic build experience whatsoever, but it would probably behoove them to have decent mechanical and/or hand fabrication skills. This will probably be great for people who are mechanics, artists, tinkerers, etc. but not so great for the less mechanically inclined. Chassis choices would then be more expensive, but perhaps come as a more finished product. If anyone has thoughts on top plate or enclosure fabrication, or experience with services that provide top plates, etc. I'd love to hear them.
The cheap Edcors have exposed solder lugs. They are also not the most beautiful transformer. They are also slightly hefty, which is a good thing, but they requires some space. The cheap Antek is really really out of this world beefy for what it is. It's also no beauty queen. What I'm getting at here is that one might consider under-the-chassis mounting options for both of these transformers. This is primarily why I had to "switch horses in the midst of a stream" (thanks FDR) and ditch the original chassis prototype for the one you see in the pics now. When you under-mount all that iron, you are using up chassis space that you can usually use for other purposes. I commonly mount chokes and caps under top mounted transformers, re-using the bolt holding the transformer to the chassis. Unfortunately, these options disappear when you under-mount. Because of these factors, I would advise anyone building this amp to strongly consider a larger sized chassis. The working area that you see in the picture is 16.5" x 9.5". I divided it evenly with the aluminum angle iron support bar you see in the pic. My chassis is 3" deep, and I believe this will give enough clearance for the iron.
I am recycling a piece of network hardware that I gutted for a chassis. This chassis cost me $5 at a junk shop. It is made of sheet steel, making it easy enough for me to drill out. I have a cheap punch kit for larger holes. I was able to make all of the chassis modifications with the following tools:
Hand drill
Drill bits up to 1/4"
Stepped "unibit" drill bit up to 1"
Punch kit for larger holes (i have a very cheap one from Harbor Freight)
Metal saw (I used an electric jig saw, but someone could use a hand saw)
I build with a lot of 6-32 screw hardware. I buy it by the box from the hardware store. I do a lot of crazy projects, so I have a lot of screw hardware. However, the final build will probably use something standard like some different sizes of 6-32.
If one was comfortable with simple metalworking, a good chassis choice that one could simply buy from the Internet would probably be a Hammond enclosure. Hammond makes an enclosure that is made of aluminum, and is 17x10x3. Radiodaze sells this enclosure for $29. It also is in a size that comes with a cage, if someone wanted that as an option for safety around pets/children. The cage is $45, but it's optional (and some people might really want it).
I guess what I'm thinking is that I might make a drill guide and instruction set that focuses on that Hammond box. Then there would be a standard part that could be included in a BOM, for simplicities sake. I can imagine that many people will deviate and put their amp in widely different enclosures, as well. I believe that the largest stumbling block for this project for many people will be the chassis work required. I can live with the target audience of a build document having no electronic build experience whatsoever, but it would probably behoove them to have decent mechanical and/or hand fabrication skills. This will probably be great for people who are mechanics, artists, tinkerers, etc. but not so great for the less mechanically inclined. Chassis choices would then be more expensive, but perhaps come as a more finished product. If anyone has thoughts on top plate or enclosure fabrication, or experience with services that provide top plates, etc. I'd love to hear them.
I see that people are eager for a time-table. I don't want to be coy, but I don't really want to speculate on that at this time. I know there must be some level of apprehension that things might never come to fruition, and be "never done", but I can assure you that I full believe that this is not the case. Wiggy is managing this project beautifully, and I believe that we will end up with a great final document describing the build process from A to Z. What we do not want to end up with is a sub-par build, and overall dissapointment in the final product. Because of that, even tho we are working diligently, I am tempted to "do it right" and rush nothing. I will have the prototype built by the end of next weekend, for sure, and then it goes to Keg for final testing/tweaking. After that, I have the joy of basically reverse engineering all that we did, and painstakingly build a new one on a new chassis while Wiggy shoots each step. When this project is finished, it will have consumed many dozen (if not hundreds) of hours of labor including the services of a few professionals including a photographer and circuit designer (or two). It's nice to see people so eager to get started, but for now sit back, watch the progress reports, and maybe set aside a buck or two!
Jim Shearer
Active Member
Hey, no rush! Like they say,"Plan the work, then work the plan." If it isn't 'done right,' then guys like me who know NOTHING won't be able to finish it.
And THANKS for all your hard work! :yes:
Cheers, Jim
And THANKS for all your hard work! :yes:
Cheers, Jim
Kegger
R.I.P. 1/12/1966 - 6/1/2017
I See Ed's point of view on the outputs not being sealed/exposed for the touch,
and some may not like there look as well as the exposed side of it, but for some
including myself I don't have kids/pets and find the industrial look of the outputs
actually kinda cool looking and will more then likely mount mine on the top side.
Nice progress Ed on the test Mule!
and some may not like there look as well as the exposed side of it, but for some
including myself I don't have kids/pets and find the industrial look of the outputs
actually kinda cool looking and will more then likely mount mine on the top side.
Nice progress Ed on the test Mule!
Sir MLS
Active Member
I have been looking to buy an S5 16LS amp kit but I am holding off to see this amp come to fruition. I am very interested and this would be a first build for me. I am a pretty good DIY kind of guy but know nothing about how to design a tube amp.
Thank you guys for all your hard work and I will patiently await the unveiling of the " final, or should the first iteration of this amp."
May be a list of the basic fundamental parts for this amp could be compiled so the newbs could start stocking up and get ready to build.
Again thanks,
Scott
Thank you guys for all your hard work and I will patiently await the unveiling of the " final, or should the first iteration of this amp."
May be a list of the basic fundamental parts for this amp could be compiled so the newbs could start stocking up and get ready to build.
Again thanks,
Scott
Wigwam Jones
Caesar non supra grammati
Scott, thanks for the encouragement and I hope you join us in this mass build. I'm a newbie too, and also know nothing about tube amp design (but I'm learning). As far as the parts go at the moment, Ed (Squidward) has done a good job of pointing out that basic hardware (like nuts and bolts) are about all that is 'for sure' right now. We don't even have a working prototype - and although we have high confidence that what we have will work - we have not proven it to ourselves yet, nor have we convinced ourselves that there is not another method that would allow better results.
Buying based on 85% certainty might be an OK risk for you - or me - but we really can't ask people to start stockpiling parts and then tell them "Oh, nevermind, we were wrong about X or Y or Z." For the experimenter or hard-core DIY tube guy, maybe that's no big deal - he tosses the parts in the box for some later project. For newbies like you and me - that's a part that will probably never be used, so the money is essentially wasted.
If you have been following along the prototype build so far, many of the parts have been discussed, such as the model number of the power transformer. But if you run out and buy that, and we decide later that it's not such a great transformer for our uses, that's no fun.
I know that the temptation is great to 'get involved' by buying parts now - it makes us feel like we're moving ahead instead of just waiting. But I would urge you - and anyone who wants to do this build but who does not already have a box o' parts or a workbench full of tubes and transformers - to hold off for now. We promise to move with all due haste - but we really, really, want to be sure that when we publish a BoM (Bill of Materials) and a schematic - they are not going to be changed in any appreciable (meaning costing you money) way.
Hang in there! Save up the nickles and dimes! We'll get there!
