Antek toroid PT for an 18w TMB build?

[joulupukki]

I’m wondering if anyone has successfully used one of these power transformers for an 18w build?

https://www.antekinc.com/power-transformers/

If so, which one, and did you have to make any adjustments or changes to voltage dropping resistors/etc?

[joulupukki]

My best guess is that this one would work, but I'll admit I'm a newbie to understanding exactly what to look for...

https://www.antekinc.com/as-1t300-100va ... ansformer/

[Bieworm]

There are plenty alternatives for that PT. I find toroidal transformers not very pretty and I understand/read they are more prone on making mechanical noise or vibrations.

[Unit_1]

I was looking at the same thing about 15 years ago and the prices for toroidal iron made it an unacceptable choice. They produce less 60hz (or 50) hum and therefore can be closer to sensitive circuits, and are used in power bricks for pedals as well as tokamac reactors so everything from A to Z that needs a quietier power source.

The pricing on the link you provided surprised me, they certainly have come down in price, and I was also surprised to see they have chokes, PT and OT's. Nice. I may have to try this afterall.

There is no reason why you can't try, it looks like they have everything you need. To mount you'd have to cut a piece of metal plate, and bolt that to the chassis using the four holes supplied for the normal PT, and drill a hole in the center of the plate for the mounting bolt for the toroid, otherwise there'd be a biggo hole and nothing to bolt to. Or you could use G10 circuit board material, it's lighter and extremely strong.

So the biggest obstacle is you'd have to fabricate the brackets. I've been using a drillpress since I was 11 so no problemo.....

[joulupukki]

Awesome. Thank you for letting me know. I think it will likely be a temporary PT until the Mojotone/Heyboer is in stock so I was thinking to just mount it on the chassis with some zip ties.

I’ll probably also use two 1N4007 diodes before it hits the plate pins on the 6CA4 rectifier as current limiters. I’ll report back how it goes and, of course, compare with the Heyboer once it arrives.

[joulupukki]

Just to report on this, it does work. I hooked it all up yesterday. If it wasn’t for my anxiousness in diagnosing a crazy loud hum problem (which turned out to be that I missed soldering the ground of the main cap can) I wouldn’t have blown the slow-blow fuse.

I’ve got more replacement fuses coming and should have it up and running quickly again.

Because this AnTek PT is a temporary I didn’t bother shortening any of the leads and so it’s a little bit of a rats nest in there. I mounted it with zip ties (I know, kind of sketchy) and in general it definitely doesn’t look normal. But the amp works (mostly - I’ve got a couple of hum/scratchiness issues to troubleshoot).

[geoff 1965]

That looks good to me, the toroids don’t have the aesthetics of a heyboer etc but if it works why not use it.
Just a point on your el84’s cathode capacitor/resistor,separate them so air can flow around the resistor as they get hot and if your capacitor is touching it will act as an heat sink.something mojotone need to amend on their layout.
Good luck

[Unit_1]

That looks good to me, the toroids don’t have the aesthetics of a heyboer etc but if it works why not use it.
Just a point on your el84’s cathode capacitor/resistor,separate them so air can flow around the resistor as they get hot and if your capacitor is touching it will act as an heat sink.something mojotone need to amend on their layout.
Good luck

I just finished my 18w layout, note the space between the capacitors and resistors.... Why did I do my own layout? I like drawing, lol... plus I can print out the template in actual size to make my own circuit board out of G10, elmers glue stick works great to stick the paper to the epoxy board before drilling........

[zaphod_phil]

That looks good to me, the toroids don’t have the aesthetics of a heyboer etc but if it works why not use it.

Good luck

Toroidal PTs tend to be built more to Hi-Fi specs and I suspect you may get a bit less sag than with a regular RS clone 18W PT.

[joulupukki]

Probably so. I am not well-versed in all of this stuff since I only recently got into tube amps. The amp sounds pretty stellar right now and I do have a proper PT on order. It’s just backordered. But I am really curious to see if I can discern any difference. I’m half-way tempted to just cancel the order and keep this toroid in there since it seems to be working pretty well and I wonder if the normal PT would introduce more hum. All of this, obviously, I’m mostly clueless about.

[Unit_1]

Probably so. I am not well-versed in all of this stuff since I only recently got into tube amps. The amp sounds pretty stellar right now and I do have a proper PT on order. It’s just backordered. But I am really curious to see if I can discern any difference. I’m half-way tempted to just cancel the order and keep this toroid in there since it seems to be working pretty well and I wonder if the normal PT would introduce more hum. All of this, obviously, I’m mostly clueless about.

I was reading the specs on those and they have internal shielding to help minimize hum. I suspect you may have more hum when you replace them.

The rumor/hearsay is they aren't as dynamic, but I've never met anyone that actually *tried* it to see.

I have a fully populated (components/wires/pots/sockets/soldered) set of Hiwatt DR504 boards (power board and main circuit board are separated on the Hiwatt) that I put together 14 years ago before the $#!+ hit the fan economically and health-wise for me and my wife, and I'm going to try using these Toroidal transformers to complete that.

Then I can compare with my DR504 with Mercury Magnetics, which is my most used amp.

[zaphod_phil]

I’m half-way tempted to just cancel the order and keep this toroid in there since it seems to be working pretty well and I wonder if the normal PT would introduce more hum. All of this, obviously, I’m mostly clueless about.

With a "normal PT" you may need to adjust the orientation of the OT to minimize hum, using the well-known "headphone trick".

[zaphod_phil]

I’ll probably also use two 1N4007 diodes before it hits the plate pins on the 6CA4 rectifier as current limiters.

How would those 1N4007s help?

[joulupukki]

I have a fully populated (components/wires/pots/sockets/soldered) set of Hiwatt DR504 boards (power board and main circuit board are separated on the Hiwatt) that I put together 14 years ago before the $#!+ hit the fan economically and health-wise for me and my wife, and I'm going to try using these Toroidal transformers to complete that.

Then I can compare with my DR504 with Mercury Magnetics, which is my most used amp.

Hope your collective health can improve. I’d love to hear how that experiment turns out for you so be sure to report back.

[joulupukki]

With a "normal PT" you may need to adjust the orientation of the OT to minimize hum, using the well-known "headphone trick".

Right. Although the one drawback on this chassis is that it’s a pre-determine location since the big square and mounting holes are already cut and drilled for the original-style PT (the Mojotone/Heyboer).

[joulupukki]

I’ll probably also use two 1N4007 diodes before it hits the plate pins on the 6CA4 rectifier as current limiters.

How would those 1N4007s help?

Not sure now actually. At some point I had read that these diodes could be used as current limiters. Not sure if that’s the case at all, but I guess for now they act as backups to the tube rectifier.

[Unit_1]

I’ll probably also use two 1N4007 diodes before it hits the plate pins on the 6CA4 rectifier as current limiters.

How would those 1N4007s help?

Not sure now actually. At some point I had read that these diodes could be used as current limiters. Not sure if that’s the case at all, but I guess for now they act as backups to the tube rectifier.

I used this as well as a capacitor. It's to prevent PT failure if the rectifier tube melts down.

[joulupukki]

How would those 1N4007s help?

Not sure now actually. At some point I had read that these diodes could be used as current limiters. Not sure if that’s the case at all, but I guess for now they act as backups to the tube rectifier.

I used this as well as a capacitor. It's to prevent PT failure if the rectifier tube melts down.

What exactly does the capacitor do in this location?

[Unit_1]

What exactly does the capacitor do in this location?

That's a very good question. My guess is to help protect the diodes if the rectifier goes out, otherwise why 3kv?

I first saw this on the "lightning" amplifier layout, on the ceriatone site.... but on a 8 pin.
http://www.ceriatone.com/ceriatone/wp-c ... iatone.jpg

[joulupukki]

What exactly does the capacitor do in this location?

That's a very good question. My guess is to help protect the diodes if the rectifier goes out, otherwise why 3kv?

I first saw this on the "lightning" amplifier layout, on the ceriatone site.... but on a 8 pin.
http://www.ceriatone.com/ceriatone/wp-c ... iatone.jpg

Gotcha. Thanks.