Rocket Power Transformer

[jul059]

What do you guys think about this power transformer for a Rocket? do you think the voltage is high enough? It's a toroidal 240-0-240 rated for 50 VA.

http://www.antekinc.com/details.php?p=671

These transformers are quite nice, especially with the cases.

http://www.antekinc.com/details.php?p=734

[rock_mumbles]

What do you guys think about this power transformer for a Rocket? do you think the voltage is high enough? It's a toroidal 240-0-240 rated for 50 VA.

http://www.antekinc.com/details.php?p=671

These transformers are quite nice, especially with the cases.

http://www.antekinc.com/details.php?p=734

I used the older version of that PT in a two tube 12AX7 and EL84 SE amp with ss diode rectifier and had a B+ voltage of about 325V ...

I have data from builds using several of the Antek PT's and they seem to have lower voltages in circuit than a standard EI transformer with the same voltage rating ...

I don't know about it powering a Rocket ... maybe a 1/2 Rocket, also there isn't a 5V rectifier tap

[overtone]

well, the 50mA does not cut it even for half a Rocket. If you want to veer off the map, one should at least keep an eye on your tube data sheets.

[jul059]

What do you guys think about this power transformer for a Rocket? do you think the voltage is high enough? It's a toroidal 240-0-240 rated for 50 VA.

http://www.antekinc.com/details.php?p=671

These transformers are quite nice, especially with the cases.

http://www.antekinc.com/details.php?p=734

I used the older version of that PT in a two tube 12AX7 and EL84 SE amp with ss diode rectifier and had a B+ voltage of about 325V ...

I have data from builds using several of the Antek PT's and they seem to have lower voltages in circuit than a standard EI transformer with the same voltage rating ...

I don't know about it powering a Rocket ... maybe a 1/2 Rocket, also there isn't a 5V rectifier tap

I realise I described the wrong transformer. Please go see the link!

In the spec sheet, it says 241 V at 0.4 A secondary. Did you wire the two secondaries in parallel?

From what I gather from this site : http://www.ampbooks.com/home/classic-ci ... power-amp/, this would be in the proper range for an AC30. Is the rocket that much different?

[rock_mumbles]

What do you guys think about this power transformer for a Rocket? do you think the voltage is high enough? It's a toroidal 240-0-240 rated for 50 VA.

http://www.antekinc.com/details.php?p=671

These transformers are quite nice, especially with the cases.

http://www.antekinc.com/details.php?p=734

I used the older version of that PT in a two tube 12AX7 and EL84 SE amp with ss diode rectifier and had a B+ voltage of about 325V ...

I have data from builds using several of the Antek PT's and they seem to have lower voltages in circuit than a standard EI transformer with the same voltage rating ...

I don't know about it powering a Rocket ... maybe a 1/2 Rocket, also there isn't a 5V rectifier tap

I realise I described the wrong transformer. Please go see the link!

In the spec sheet, it says 241 V at 0.4 A secondary. Did you wire the two secondaries in parallel?

From what I gather from this site : http://www.ampbooks.com/home/classic-ci ... power-amp/, this would be in the proper range for an AC30. Is the rocket that much different?

My brother and I and several others have used/tested and shared voltage data for several different Antek PT's (granted most of our testing was done on the AN series transformers and now they have changed a bit and are the shielded AS series) ... from our testing, their data does nor correlate with our in use data, some PT's do perform better than others ...

Our testing was done on low power SE and PP amps with an 18 watt being the highest current draw circuit ...

I now see the error in their spec's ... their spec's are what you would get if you only load the HV taps ... in a tube amp both the filament supply and HV are loaded so you will not get 241V @ 400mA from the HV with a heater load on the transformer ...

The Antek 1T300 works well in a ss diode rectified 5E3

I used Duncan's PSUD II to model an amp with the Antek 1T250 ... in that amp it modeled as a 250V 90mA transformer ...

I've used the Antek HV primaries in both a center tap orientation with a full wave rectifier and paralleled with a bridge rectifier both give about the same voltages ... lower than an Edcor, ClassicTone, Hammond transformer with the same spec's.

It would only be a ~$45 experiment to see if the AS-1T250 will work in a Rocket or not ... so build a ss diode rectified Rocket and hook one up and see how it works

They are cheap PT's ... I use them in experimental builds, amps that I don't really value ...
Also the case you have referenced is for one of the 50VA PT's not a 100VA PT so that won't work.
As far as I'm concerned it's not worth spending the ~$20 on the case ... you'd be better off spending another $25 or so on a real Rocket PT.

[jul059]

Thanks rock_mumbles.

I'm thinking it might give some great sag to the amp. What do you think?

[jul059]

sorry, double post.

[rock_mumbles]

OK, I just did the math on an AC-30 PT, I'd expect the same for a Rocket ... it's a 200VA transformer ... the Antek is a 100VA transformer.

So it looks like my initial feeling that the Antek would be OK for a 1/2 Rocket was correct ...

[jul059]

Right. Thanks! Looks like I'm out of luck. The next 200VA available transformer from Antek is 300V. A little too high I think.

[Hepcat]

I have purchased three transformers from them in the past before I knew how to figure the final rectified and filtered voltage under load. Unfortunately, no matter what configuration I chose, the end voltage was well over 500 volts, too much for even the JJ 6L6 and 6V6. I don't quite understand why they would make tube power transformers that aren't useful for guitar amps. Yes I know I can use an EL34 setup with a lowered screen voltage but I leave that to the Hi-Fi guys. I'd use them in my amps if they worked.

Ken Zuercher
Zuercher Amplification
www.zuercheramps.us

[jul059]

I have purchased three transformers from them in the past before I knew how to figure the final rectified and filtered voltage under load. Unfortunately, no matter what configuration I chose, the end voltage was well over 500 volts, too much for even the JJ 6L6 and 6V6. I don't quite understand why they would make tube power transformers that aren't useful for guitar amps. Yes I know I can use an EL34 setup with a lowered screen voltage but I leave that to the Hi-Fi guys. I'd use them in my amps if they worked.

Ken Zuercher
Zuercher Amplification
www.zuercheramps.us

What was the rated VAC of your transformers that had over 500 VDC once rectified?

[Hepcat]

350 Volts per secondary. 700 total Pk to Pk. So 700 divided by two is 350 (duh) X 1.414 give 494 volts after rectification. Needed 325 and didn't know then (three years ago). The transformers are still on a shelf (just looked at them to get the secondary voltages.

[Hepcat]

Just returned to the Antek web site. The only 320 volt transformer is a 50 watt unit. They do have a 275 X2 100 watt unit (out of stock naturally) for $34 but it has no 5V winding. I'm OK with the SS rectifier and may do a version of a Rocket,mixed with a Matchless DC30 to see what it sounds like. I don't clone amps anyway, just start with the best designs and tweek them to my taste.