rocket transformers

[M Fowler]

OK now I have a question regarding wiring the A-470S OT. The wiring instructions notes:

Primary 4300 ohms CT

Blue/white to plate tube 1
Green/white to screen tube 1
Red B+
Green to screen tube 2
Blue to plate tube 2

Secondaries:

Black common
Brown 4 ohms
Orange 8 ohms
Yellow 16 ohms

I don't find that I would need to use Green/white or Green wires is that correct?

Mark

[mlp-mx6]

Correct. The "screen" wires would be for ultralinear connection, which your amp (according to the schematic) does not use.

[M Fowler]

mlp-mx6,

Thanks for the reply I was sure this was the issue but you know two heads are always better than one.

Mark

[Ron Worley]

Both Allyn and RJ had some, not sure if they still do.

Heyboer will make a one off for you, it will just cost a bit more ( I had a custom 120 / 240V Express PT done, and it was about $30 more than ToneSlut's price.

I would suggest that there be a group buy of them =- One guy takes the lead, orders 10 or so, then handles the shipping of them, just like Allyn did. Hell, Allyn might be up for another buy if there's' enough shown....

[Zippy]

Before we jump all over a group buy, is there yet a concensus on what is "right"?

[joebob]

This OT seems like it would work for a Rocket: 4200 & 4,8,16 output, rated at 60w at $70. They have nice PT's too.

http://www.edcorusa.com/products/transf ... -4_2k.html

[M Fowler]

I had to go to three different suppliers to get my Rocket trannies. The choke 158L from Parts Express. The OT A-470S from Triode. And since I could not find the PT I'm experimenting with one from RJ 245-0-245.

Looking back I was told I could have just used the 260-0-260 and I think that would have been fine. I didn't like the wiring for the A-470S it was very small primary wires and different color coding from the Heyboer.

Not sure I want to build another Rocket at this point it has been a pain.

Mark

[dave g]

I didn't like the wiring for the A-470S it was very small primary wires and different color coding from the Heyboer.
Mark

What gauge wire do you think is used to wind the primary itself on your typical OT?

Yes, the color coding is different from Heyboer's because it follows the original Dynaco code.

I personally like the Dynaclone A470 better than Heyboer's. YMMV

[M Fowler]

Dave I was just blown away for a while at the smaller size of the wire compared to the Heyboerl. I am over that now and your right. I am sure that this will be a great amp when I get 5 watt screen resistors I seem to have misplaced or did not order.

Mark

[RJ Guitars]

This OT seems like it would work for a Rocket: 4200 & 4,8,16 output, rated at 60w at $70. They have nice PT's too.

http://www.edcorusa.com/products/transf ... -4_2k.html

I looked at these units when we were doing the group build on the Rocket amps and found there was not room for it on a standard wreck chassis. At that time we really didn't have the official transformer specifications for the Rocket (...do we know absolutely that Ken Fischer used a Heyboer wound Dynaco 470 variant???). You can see one Rocket build rear view on the back of the Dave Funk built Malou amp. http://www.thunderfunk.com/History.html Is that a Heyboer?

Make sure you take a look at the footprint of this unit, it's huge... although I believe the quality is very good and the price is excellent. Just make sure you've got lots or real estate. Edcor caters to the HiFi community and oversized is the norm for most of their iron... I have been working with them to develop a more appropriately sized 35 watt tranny... I'll report on that after I get the prototypes here to review.

rj