NEW EXPRESS BUILD!! A FEW PROBLEMS!! NEED HELP!!

[bigbeck]

I've only seen them in HI-FI builds. But the price kind of makes me wonder too. Maybe they're better in some ways than conventional iron? In the majority of cases, you get what you pay for. But there are exceptions.

Since a PT has no bearing on tone,unless it's vibrating like hell or injecting noise into the circuit, I don't see why they can't be used.

I just can't imagine a cork sniffer using a pair of these cheap PT's in his rig. They'll pay more than that for a couple of caps.

[soma_hero]

I used an Antek in my GainClone and it works perfectly, no heat issues at all.


Prslespaul, unhook your heaters and measure each one. What do you get, 3V on each or 6V on each?

[paulster]

How come more guys aren't using these?

Is there something wrong with using a toroid PT?

I've only seen them in HI-FI builds. But the price kind of makes me wonder too. Maybe they're better in some ways than conventional iron? In the majority of cases, you get what you pay for. But there are exceptions.

Since a PT has no bearing on tone,unless it's vibrating like hell or injecting noise into the circuit, I don't see why they can't be used.

Toroids differ from EI transformers in a number of areas. One is that magnetic leakage is much lower, which is a good thing. It means that you can place it much closer to the OT or to other sensitive components and it won't induce 50/60Hz hum anywhere near as much.

Another is that their regulation tends to be better for a broadly equivalent size. This means that under load they'll typically sag less, so exactly what you'd want in a hi-fi build.

If the sag under load is different, the voltages in the amp under load will be different and consequently the sound will be different. This is a fact, and is how power transformers do affect tone. For the most part though, a 50W PT (for example) from most manufacturers will have a broadly similar stack size and similar winding gauges, so its performance will also likely be in the same ballpark. It will have more of a bearing when a transformer's ratings are really pushed, which is common of vintage amps.

However, since we don't know what the regulation figure on the original Wreck PTs was, and I don't imagine anyone has measured it and compared it to this particular toroid we can't say whether or not it will practically behave differently in its real world application, even though the specified secondary voltage may be the same.

Toroids are also more prone to core saturation and have a wider passband, which means that noisy mains can result in more noise reaching the secondary than with an EI transformer, so it's something else to consider.

If you're specifying a new transformer for a ground-up build I can't see a good reason for not using one as the behavioural differences between a toroid and an EI can be factored in to the design. If you're trying to clone an amp and the original iron is still available though, it is one less variable to worry about to go for the same iron.

[bigbeck]

If the sag under load is different, the voltages in the amp under load will be different and consequently the sound will be different. .

I agree with that. But if the PT is sized properly to begin with,there will not be enough sag to make a difference - except maybe to a dog. So maybe I should revise my earlier statement to: A properly sized PT will have no effect on tone that the average musician can actually hear while playing the guitar through it..

I do realize that many vintage amps had the wrong size PT in them,along with poor filtering. So if you're building something vintage, you have to be wrong in order to be right!


I just think that the PT is an extremely trivial component as far as tone goes,providing it's sized correctly. There's just too many other bigger fish to fry in any given build, that even us non-dogs can hear.


Thanks for the info on the toroids.

[mlp-mx6]

Given that the available current from a spec Wreck power xfmr is pretty stout, I don't think sag is much of an issue. 250ma is plenty for a 50W (or more) amp.

[paulster]

So if you're building something vintage, you have to be wrong in order to be right!

That's it in a nutshell!

And, yes, the Wreck transformer is pretty stout and the filtering is quite high, so I think this particular toroid will likely work well.

[bigbeck]

I just ordered 2 of these PT's. One for a Wreck and one at 200V for a little 6BM8 Push pull build. That one is $29.00

I'm trying to do it all wrong so it comes out alright! Does that make sense?

[paulster]

I'm trying to do it all wrong so it comes out alright! Does that make sense?

It wouldn't be you otherwise!

[bigbeck]

I'm trying to do it all wrong so it comes out alright! Does that make sense?

It wouldn't be you otherwise!

Spoken like a man who knows.

[bigbeck]

I used an Antek in my GainClone and it works perfectly, no heat issues at all.


Prslespaul, unhook your heaters and measure each one. What do you get, 3V on each or 6V on each?

What did you get on yours? 3V would be nice because you get a CT out of the deal. And if they're 4 amps @ 3V they'll be 8 amps at 6V. Right?

[bigbeck]

Well I have the AN-2T300 in my possession and the heater taps are not what they show on the website schematic. one is 6.3V and the other is 12.6V. What's the best way to drop 6 volts on that 12.6 volt tap?

I didn't actually test these heater taps. I just read the label that's attached to the PT.

[paulster]

Use the 6.3V tap for power tubes and the 12.6V tap for preamp tubes with the heaters in series rather than parallel.

[bigbeck]

I knew there had to be a reason as to why I liked you. Thanks

Maybe this is the reason why prslespaul had crazy sh!t going on with his heaters. Although he said he had both taps in series and got 6.3V.

I sent Antek an email about one of the heater taps being 12.6V on the tranny label and 6.3V on the spec sheet. Maybe that's why they're so cheap - you never know what you're going to get.

I did get a response from them a couple of days ago as to why the description page shows 3V taps - It's a typo!

Let's see here, one page shows 3V heaters, the schematic shows two 6.3V heaters, the label on the PT shows one 6.3V and one 12.6V heater tap.

Is it any wonder that no one uses these f*****g things! Wonder what I'll get when I hook up a meter?

I also bought the AN-1T200 and the tranny label does indeed match the schematic. So that one is ok - maybe.

[bigbeck]

I just got a response from Antek about the 12.6V secondary on the 2T300 PT.

They actually have two versions of this PT. One has two 6.3V secondaries and the other has a 6.3 and a 12.6. They're shipping me the correct one at their expense.

[passfan]

Working in the electrical industry it's common knowledge that windings in transformers have a polarity. I wonder if you swap ends on one of the windings you are trying to parrallel and see if it runs cooler then. Forgive me if you solved this already , I got lost on page 2 and may have given up and replied prematurely.