Author Topic: Classic amp topologies made with submini tubes  (Read 16499 times)

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Kevin Mitchell

Re: Classic amp topologies made with submini tubes
« Reply #40 on: December 19, 2016, 02:51:58 PM »
I haven't even come close to finishing my submini blackface style amp  :icon_lol: 

Lookin' great Thomas!

thomasha

Re: Classic amp topologies made with submini tubes
« Reply #41 on: February 07, 2017, 03:25:06 PM »
finally made a video for this one, is there someone still interested in these small amps?


Kipper4

Re: Classic amp topologies made with submini tubes
« Reply #42 on: February 07, 2017, 03:47:43 PM »
That's great Thomas.
Yes I'm still intrested, I will eventually get around to doing one.
Don't give up the good work mate.
Jellybean dodging since 2012.
Smoke me a Kipper. I'll be back for breakfast.

Metaldestroyer

Re: Classic amp topologies made with submini tubes
« Reply #43 on: April 10, 2017, 02:13:33 AM »
Alright, here it is in its open, unboxed form. Only took 3 years to make.



It isn't quite a classic amp topology but it is based on a Top Hat Club Deluxe which is based on an AC30 Top Boost channel. I used 6n17b for the preamp, 6n16b for the PI and 6p30b for the output stage. The whole thing runs off of a 12v DC adapter which then goes through 2 SMPS: one MAX1771 for the HV and one TPS564201 for the heaters. I'll post a full schematic when I get around to drawing one; the one I worked off of to build it has some mistakes and I changed quite a few values in order to get it working.

When I first plugged it in, it sounded grainy and was barely audible. So I went back in and replaced the PI circuit with the one Thomasha used for his JCM800, which didn't solve the problem. Then I noticed I forgot to ground the OT secondary, which made the whole amp stop making sound. Then I figured out I had flipped the secondary common and one of the primary leads  :icon_redface:. It's a wonder the thing output any sound at all, but somehow I didn't kill the tubes or the transformer so it's fine I guess. Now all that's left is to take the whole thing apart and put it in the box.

tommycataus

Re: Classic amp topologies made with submini tubes
« Reply #44 on: April 13, 2017, 03:55:15 AM »
I'm definitely still interested in this subject. Metaldestroyer, that looks and sounds awesome! I'd love to glance at a schematic if/when you have time to draw one.

The problem I am having is mainly due to the fact that I'm new to building tube amps. Other than specific transformers that are named, I don't understand what to look for. I do understand the risks and have worked with high voltage circuits before.

I'm guessing the SMPS circuits negate the need for a power transformer, but what about the output transformer? What do I look for in the primary and secondary coils? Am I limited to only a few options or are there myriad choices out there? I'm keen to learn more about this component in particular, but Google falls a little short on the detail. Thanks in advance.
"Remember, there's a big difference between kneeling down and bending over." - FZ

jubal81

Re: Classic amp topologies made with submini tubes
« Reply #45 on: April 14, 2017, 01:27:53 AM »
That TPS564201 looks like a great chip. Looking forward to seeing the schem. Great work!

thomasha

Re: Classic amp topologies made with submini tubes
« Reply #46 on: April 14, 2017, 10:13:38 AM »
Nice build, hoping to see some pictures too, it already looks interesting with those chicken head knobs.

You could also tell us more, if there were any problems with your build

I wanted for some time, to make something fail proof, so it would be easier to other members to build, but the SMPS is always the most problematic part and introduces a lot of noise if not tamed adequately.
If you managed to get around this would love to see your layout and which inductor  and mosfet you're using with the MAX1771.
I found some good inductors some time ago, but during me testing there was also a lot of them that just vibrated too much, and produced this coil squeal sound.
Another member showed me a guy at ebay selling smd SMPS that could deliver up to 20W at 200v. Maybe that could make the whole process easier.

You had luck with your build problems, the tubes and OT are more forgiving than the SMPS chip, I think I lost the track of how much I already burned just because one filter cap had a bad solder joint.

keep the good work going!



Metaldestroyer

Re: Classic amp topologies made with submini tubes
« Reply #47 on: April 20, 2017, 02:22:47 AM »
I'll just drop this off here  :icon_biggrin:



I'll do a full write up with schematics, stories, pictures, etc. when exams stop

thomasha

Re: Classic amp topologies made with submini tubes
« Reply #48 on: September 12, 2017, 06:01:43 PM »
wow that looks awesome, need to make some pictures like that.

Some time ago I finished another build, that was more like a remake of an older amplifier.
The superfly using russian tubes never had enough gain to me, (at lower volume settings...).
So I changed it to something in the line of the jjs amplifier with only one triode in SE.
The circuit and the looks where both night train inspired, and I named it the "Tiny Nightingale"

Here some pictures:






Cheers,
Thomas
« Last Edit: September 13, 2017, 09:05:26 AM by thomasha »

tonyharker

Re: Classic amp topologies made with submini tubes
« Reply #49 on: September 13, 2017, 08:33:06 AM »
Can you make your pictures larger please?

EBK

Re: Classic amp topologies made with submini tubes
« Reply #50 on: September 13, 2017, 08:36:02 AM »
Can you make your pictures larger please?
If you take out the "m" at the end of his links, you can see the larger version.
No affiliations. If I glowingly mention specific merchants or products, it is because I like them without having to be paid to like them.

Ripthorn

Re: Classic amp topologies made with submini tubes
« Reply #51 on: September 14, 2017, 01:43:33 PM »
Maybe 5 years ago I made a 2W plexi/JCM800.  It was based around a 1959 super lead, but when I saw how similar it was to the JCM800, I worked up a relay switching system that would allow me to be in plexi mode with either input 1 or inputs 1 and 2 jumped and then I could flick a switch (or use my foot switch) and go into a JCM800.  It sounds quite good, but I don't use it a ton.  I'm thinking of building something else into that chassis.
Exact science is not an exact science