Choke choice

[Tdale]

What would be a good choice for a choke for a Rocket (Z-wreck)?

A link to a website would be greately appreciated!

Tommy

[selloutrr]

the schematic says 15 Henry 25mA I believe the original Choke was made by Stancor. no longer in production.

Try Tubesandmore.com

Hammond P-T155J

Filter Choke - Hammond, Open Bracket, 15 H, 30 MA
Specifications
Rating: 15 Henries, 30 mA
Max. VDC: 400
Resistance: 1,026 ohms
Mounting centers: 2" u-frame
Weight: 0.3 lbs.

RoHS Compliant

Economical "open bracket" - channel mount.
Tolerance of 15% on both inductance & resistance.
Inductances measured at rated D.C. current.
Minimum 5" long leads.
Units will exhibit less inductance at slightly higher currents or more at lower currents.
Perfect for high voltage power supply filtering.

[Ken Moon]

I thought the preferred choke was the Hammond 158L, at 15 H and 75mA (400R dcr).

I don't think that 30mA choke has enough current capability.

[Ken Moon]

Good sources for Hammond trannies/chokes:

stf-electronics.com
angela.com
radiosupply.com

They all have the 158L for about $21 plus shipping.

[surfsup]

Edcor has a 15H 75mA 440R choke also. I just ordered one.

[M Fowler]

I thought the idea is to get a choke that has the correct DCR and mA rather then matching the Henry's. Pick a choke with DCR of roughly 400DCR 75mA then look at the henry. Correct?

The wreck is diferent less DCR and higher mA

Mark

[Ken Moon]

I think the difference between a big choke with, say, 100 ohms DCR, vs. a smaller one with 400 ohms DCR, would only be a few volts drop in the screen and preamp voltages - the total load the psu sees on a Rocket should be much larger than that 300 ohm difference. You'd see a similar variation from different line voltages.

Choosing the right current capability seems more important - if it's too small it could smoke, and if it's too high, the choke will act like it has less inductance than it is rated for, since inductance is inversely related to current.

Just guessing, though - youse guys are the experts on these amps, so feel free to bash me on the head if I'm wrong

[Tdale]

But what are the values I'm looking for in a Rocket? H, Ohm, mV ?

Anyone know what is in the original?

Tommy

[Ken Moon]

I think there are a lot of threads on this, so try some searching.

The correct specs are 75mA, 400 ohms DCR and 15H. I think some of the previous threads go into details about the original Stancor (IIRC), which is no longer made.

[RJ Guitars]

The Edcor "Rocket" choke was made to my specifications at 15H, 75mA, 347 Ohms. These were the specs provided to me as appropriate for a Rocket build . I was a little surprised to see this choke listed on the Edcor web site but I suppose I never ask them to protect the part number. Most of the Wreck transformers we have were made available because Rob Hinson chose not to protect his part numbers... which I think was extremely decent of him.

The Edcor is similar to the Hammond 158L although i think you'll find the Edcor craftsmanship to be a cut above almost anyone else in the transformer business.

rj

[selloutrr]

I just pulled from the Rocket Stickie

if it's 75mA

it might be good to update the files

Taylor Rocket Schematic- Updated 6-5-08.pdf

[RJ Guitars]

You are right, I never saw that before.

You will see AC30 chokes rated at 15H, 19H and 20H, but always at 100mA.

In the case of Trainwreck, I think Ken Fischer used what he could get his hands on and didn't see the need or want to pay the tariff for VOX OEM parts. I know this will bring cries of anguish but concerning a choke in this particular spot on this particular circuit, if you get close, it's close enough.

rj

[M Fowler]

For non trainwreck (wreck) your looking for 170ohm DCR and 150mA from 5H to 10H will work.

You look for the DCR, then the mA, and finally the Henry.

For my wreck I used the Hammond, Open Bracket, 7 H, 150 mA
Specifications
Rating: 7 Henries, 150 mA
Max. VDC: 500
Resistance: 100 ohms
Mounting centers: 3.56" u-frame
Weight: 2.3 lbs.

RoHS Compliant



Mark