Egnator Rebel 30 Power Tx secondary voltages???

[J M Fahey]

Oh, no problem.

Personally Iīd make very certain about what the proper voltages are, as in, as Dave H suggested: 380V DC , not AC, meaning 280+280V AC ; not sure abias tap , maybe somebody can measure what that amp (or a similar one, fixed bias uses) but in any case 50 or 60 VAC looks reasonable, in any case better than 260VAC, would estimate current for all and specially filaments, and plain order a properly made one.

I think the original one was marginal , lots of them fail, a new one wound to same specs may be somewhat better, only because it uses better iron , not much improvement possible for copper because "copper is copper" and the main problem is getting much more of it inside the same window space.

And there we have the problem with the one you have today: since window space is strictly limited:


when your winder calculated wire diameter both for filaments and high voltage, filaments 200% of what was needed and HV 140% of proper value, he had to use thinner wire.
Thinner than what was originally used, which was already marginal.

So even if you drop *voltage* , wire will still be way too thin and overheat, so my suggestion is that after the Forum reaches an agreement on whatīs needed, with input from various members, Iīd wind a new, properly sized one and be safe.

Unfortunately, although the *brand* is Egnater, Bruce has not much say (as in *zero*) about what they do.

Heīs a member in various Forums, even here, and already explained the problem: he sold the designs and the use of the name to a group of investors, who clearly want to get rich quick, and apperently chose cheap suppliers in China, *specially* for the transformers.

The electronics side seems to be well made but they had tons of problems with transformers, plus they seem to have ordered a million of them, so when people has a problem, they send a new one ..... "more of the same", thatīs why I am not suggesting to order an original one from Factory but an aftermarket one, or a `properly specīd and wound one.

FWIW I have pictures of what the Factory sent as replacements : the exact same transformer, with the covers crudely perforated (on a desk drill or worse) for "ventilation" and a 12V PC type fan, to be mounted pointing to the transformer and cooling it

Bruce Egnater has no control over that and is obviously dismayed at the use (abuse) they are giving to his brand.

[robo]

Hi J M Fahey,

I agree it would be more sensible and safer to have another Tx made with the correct voltages.

My estimation would be for transformer secondaries :

HT: 260vac--280vac(max) ct 260vac--280vac(max) @ 200mA

BIAS TAP: 100vac @ 100mA

FILAMENT: 3.15vac ct 3.15vac @ 3A(min--to provide for 2x 6V6; 2x EL84; 1x 12AX7(P.I.))

LT: 15vac ct 15vac @ 2A(min--to provide regulated 12vdc for: 4x12AX7 Pre-Amp Tubes; and Op- amps and Relays)

I think that should work?
What do you think?

I didn't know about Bruce Egnator selling Egnator Amplifiers,that is a shame seeing as the people whom bought it dont seem to give a fig
about their customers,yes the old favourites rearing there ugly heads...Avarice and Greed! Great Shame.

Thanks again for your help.

[J M Fahey]

We are getting closer but we still need some extra data.

We have no idea of what voltage is actually needed at the bias tap and the low voltage regulators.

Iīll post the power supply section (empty) schematic and please fill the unknown parts values, you have the actual amp there and can check them, then we can adjust our estimates.

Just 2 points that make me go slow on this: just comparing to other amplifiers, 100VAC bias tap sounds almost twice as usually needed; you do not need to specify a mA rating for it, itīs just a tap from the main winding; but if you do, transformer maker will follow your instructions faithfully and either wind an unnecessary extra winding just for this (remember we are iin a tight place) or wind part of the main winding just for 100mA instead of 200mA as needed.

The transformer winder will not reengineer your design because thatīs not his job, heīll faithfully do what you order, good or bad, so be careful on what you ask for.

Hope some other Forum members have also some suggestions, for example I would like to know what a "normal" bias tap VAC and 6V6/EL84 VDC fixed bias is, to better suggest what you may need and any other consideration they might add.

So far the original idea had been to try to save what you had, and in principle I would have agreed, but I guess even if you solve the voltage problem, that weīd be stuck with too thin wire, thatīs why I suggest winding another.

Didnīt suggest rewinding the same because seen from a commercial winder point of view, itīs a huge waste of time and they canīt reuse the old wire on a new job, pulling already varnished (read stuck together) laminations is a mess, etc.

Might make sense if you had wound it yourself, because you donīt pay yourself a salary but would consider it a hobby, but itīs not the case.