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Dowdy Chokes

73.192.21.240

Posted on January 6, 2016 at 13:12:12
deafbykhorns
Audiophile

Posts: 650
Location: Florida
Joined: October 17, 2003
What is the physical size of this plate choke and inductance if gapped for 50ma?
Also looking for Grid choke henries of BCP 16NI

 

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RE: Dowdy Chokes, posted on January 6, 2016 at 15:10:56
mqracing
Manufacturer

Posts: 4302
Joined: June 29, 2000
This will be my third attempt to post a reply. Darn cell phones and tablets... pain in the ass. Finally have gone to my desktop to post. Shew.

anyway... stock Dowdy plate choke is gapped for 40 madc and produces approx 125 henries. If gapped for 50 mils the expected L would be approx 100 henries. These come supplied in bell end caps. Weigh approx six pounds each. Stand 3.375" tall.

If you know or can picture the Dynaco Stereo 70 ouput... this guy is about the same size... it just has 3/8ths of an inch less stack.

The BCP-16 grid chokes come in channel frames (steel or brass). they are shirt pocket models--- you can fit two into your shirt pocket. L varies with which core material is chosen. Where (circuit wise) would you be using it?

MSL













Builder of MagneQuest & Peerless transformers since 1989

 

RE: Dowdy Chokes, posted on January 6, 2016 at 16:00:54
mqracing
Manufacturer

Posts: 4302
Joined: June 29, 2000
values of L (OCL) per core material choice for BCP-16 grid chokes.

M6 >1000H

Low Ni >2000H

High Ni >3000H

can also be supplied with a small air gap for 1 madc with a yield of 400H

Was originally designed by Freed Transformers as a plate choke in the early to mid fifties.

The conservatively stated L's hold whether the grid choke is a Junior or Senior model.
The approx dcr's are Senior 3800 ohms. Junior 2400 ohms. Remember that in this case dcr
might well be your friend (think damping). Juniors have the advantage of lower winding capacitance.
Pricing is near the same with a slight premium for senior due to more of the expensive core material in it.

Recommendation. High nickel works best in low drive (ac volts) applications... where the voltage across it will be
less than five or ten volts. For a typical use between driver tube and output stage of a power amp (where drive level is
say thirty, forty, fifty and up volts) the low nickel or M6 is the better choice.

Always comes in channel frames. Steel standard. Brass optional.
Supplied with solder terminals (you supply the hook up wire of your choice).

MSL






Builder of MagneQuest & Peerless transformers since 1989

 

RE: Dowdy Chokes, posted on January 8, 2016 at 07:01:43
deafbykhorns
Audiophile

Posts: 650
Location: Florida
Joined: October 17, 2003
Plate choke (43ma) to 2A3(JJ40W)-- Cap -- Grid Choke --GM70

I think the Dowdy would work great in this scenario

 

RE: What is the footprint (L x W), posted on January 8, 2016 at 19:12:34
deafbykhorns
Audiophile

Posts: 650
Location: Florida
Joined: October 17, 2003
.

 

RE: What is the footprint (L x W), posted on January 10, 2016 at 04:08:10
mqracing
Manufacturer

Posts: 4302
Joined: June 29, 2000

Dowdy plate choke

mounting depth 2.375"
overall depth 3.5"

mounting width 2.25"
overall width 2.8125"

height 3.375"




Builder of MagneQuest & Peerless transformers since 1989

 

RE: Ready to order a pair in 50ma, posted on January 21, 2016 at 18:37:26
deafbykhorns
Audiophile

Posts: 650
Location: Florida
Joined: October 17, 2003
These are good for 400-430?

 

RE: Dowdy Chokes, posted on March 17, 2016 at 13:12:03
deafbykhorns
Audiophile

Posts: 650
Location: Florida
Joined: October 17, 2003
Mike with Magnequest can wind some nice looking iron.
Changing my 300b-IT-GM70 to 300b- Dowdy Choke -Grid Choke- GM70 and bumping up current from 28 to 45ma.

I was using a Hammond 126 IT, things should improve somewhat.
Hammond also had to replace one of my 726 transformers, it hummed like crazy and end bells were ringing.



 

RE: Dowdy Chokes, posted on March 19, 2016 at 01:30:45
mqracing
Manufacturer

Posts: 4302
Joined: June 29, 2000
Great picture. Thank you for your post. I enjoyed making the Dowdy's for you!



Builder of MagneQuest & Peerless transformers since 1989

 

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