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Grid Chokes

Posted on August 17, 2016 at 09:56:39
Gordon Rankin

Posts: 2836
Joined: June 9, 2000
Hey Mike,

What are the option and sizes and any details on the Grid Chokes you are offering? I know there is the BCP16GC, but didn't you start making a smaller one?

J. Gordon Rankin


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RE: Grid Chokes, posted on August 18, 2016 at 20:58:50

Posts: 4307
Joined: June 29, 2000
Here is a grid presentation of the various models\options of the BCP-16 GC (grid choke).

Original size (let's call it Senior) is available in two different coil configurtions. The standard and the Plus. The plus coil is our special winding configuration which is a symmetrical twin coil (mirror imaged) noise canceling (humbucking) design. The Senior is available in M3, M4, low nickel and high nickel.

The senior yields >1000H on the M series lams, >2000H on the low nickel and >3000H on high nickel.

Approx winding resistance of the senior grid choke is 3800 ohms.

The senior should be ordered when your swinging tens of signal volts. And for higher levels you'd want to stay away from the high nickel. I can advise upon your inquiry.

Also don't discount the M3.and M4. options. Even at the published spec (1000H) the impedance is 63.8K at 20 hz. At 30 hz the inductive reactance is 94.2K. As you double the frequency the inductive reactance. also doubles.
For example it would be 188.5K at 60 hz and a whopping 314K ohms of impedance.

The technical advantage of the M series is that they have much higher max flux density capacity and we are operating them significantly below that maximum value. Hence they will have very, very low distortion.

remember that nickel should (if you value clean reproduction) be operated at far, far lower flux densities. As an approximation low nickel should be operated at half of the available flux capacity of the M. series lams and high nickel at only approx a quarter of the value of the M. series.

We also have available a junior sized BCP-16 GC. It has a reduced core area (smaller lamination size and stack). It is intended for low signal level applications like in a preamp as just one example.

The junior is also available in the standard coil design as well as the plus series upgrade as discussed above. The junior is available in both high and low nickel. Generally you will want one of these two depending on drive level.

Interestingly since L is a function (in part) of the magnetic path length the smaller and more efficient magnetic circuit of the junior yields results that will meet the min inductance figures published for the senior grid choke.

The DCR is approximately 2400 ohms.

All of our grid chokes are supplied in channel frames. On the senior you can choose between brass or steel channels. The junior is only available with steel channels. All of our grid chokes come with solder lugs (terminals) so that you can use whatever hookup wire you prefer.

Hope this is helpful.


Builder of MagneQuest & Peerless transformers since 1989


RE: Grid Chokes in vintage low nickel, posted on August 19, 2016 at 10:27:30

Posts: 4307
Joined: June 29, 2000
thanks Alonzo for reminding me that I have some inventory of vintage low nickel for the senior grid chokes. This is a fifty plus year old stash that was made by Allegheny Ludlum and converted by the Arnold Engineering Company.

Builder of MagneQuest & Peerless transformers since 1989


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