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May 08, 2021, 05:37:12 AM

Author Topic: Similiarities to Western Electric  (Read 190 times)

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Offline tim273

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Similiarities to Western Electric
« on: May 04, 2021, 03:58:07 AM »
I saw this on the Western Electric site and it looks like they are using some of the same technology as you mentioned on the technology page of this site:  https://www.westernelectric.com/91e. Great minds think alike!

Offline Paul Birkeland

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Re: Similiarities to Western Electric
« Reply #1 on: May 04, 2021, 05:11:44 AM »
It's interesting that they are using parallel feed iron.

To get 20 watts out of a 300B, you'd have to run it at maximum voltage and near maximum plate dissipation and drive the grid positive.  This is a decision that will come at the expense of tube life.
« Last Edit: May 04, 2021, 05:23:02 AM by Paul Birkeland »
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Offline tim273

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Re: Similiarities to Western Electric
« Reply #2 on: May 04, 2021, 05:25:17 AM »
It's interesting that they are using parallel feed iron.

To get 20 watts out of a 300B, you'd have to run it at maximum voltage and near maximum plate dissipation and drive the grid positive.  This is a decision that will come at the expense of tube life.

Apparently they say their design doesn't sacrifice tube life:

"Our patented steered constant current source always keeps the tubes within their safe operating area. This means full power dissipation without sacrificing tube life."

Offline Paul Birkeland

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Re: Similiarities to Western Electric
« Reply #3 on: May 04, 2021, 05:29:49 AM »
Here is what the old WE datasheet said on the subject. 

I'm actually building a high power 300B amp for a local customer who wanted something a little different, and I warned him to always have a spare set of 300Bs on hand and not to expect a whole lot of life if he pushed the amp hard. 

On the positive side, if you assume the possibility of pressing into A2 at higher powers, you can load the 300B with a 5K output transformer and get really nice overall performance and the high power.
« Last Edit: May 04, 2021, 07:11:35 AM by Paul Birkeland »
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Offline Deke609

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Re: Similiarities to Western Electric
« Reply #4 on: May 04, 2021, 09:03:09 AM »
... On the positive side, if you assume the possibility of pressing into A2 at higher powers, you can load the 300B with a 5K output transformer and get really nice overall performance and the high power.

From the WE website blurb: "Class A3 parallel feed single-ended triode topology"

What on earth is "Class A3"?  Some middle ground between A2 and AB?

It will be interesting to learn more about how the amp's "Microprocessor controlled bias" works.

cheers, Derek
Derek
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Roon Intel NUC ->  Yggdrasil DAC -> BeePre (w/ BeeQuiet and EML 300B)  -> Kaiju (w/ DCFil and EML 300B) or Stereomour II (2A3 [EML Mesh] and 45 Conversion [EML 45B])  -> Audeze LCD4

Offline Paul Joppa

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Re: Similiarities to Western Electric
« Reply #5 on: May 04, 2021, 09:27:15 AM »
So far, it's all marketing-speak. My guess is that their "steered constant current source" approaches push-pull with a dynamically-varying "constant" current. There's an old engineering joke about dazzling with detail vs. baffling with [email protected]#t, which is probably relevant here... :^)
Paul Joppa

Offline Doc B.

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Re: Similiarities to Western Electric
« Reply #6 on: May 04, 2021, 09:59:13 AM »
I saw this on the Western Electric site and it looks like they are using some of the same technology as you mentioned on the technology page of this site:  https://www.westernelectric.com/91e. Great minds think alike!

The phrase that came to me was "imitation is the most sincere form..."
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Offline Deke609

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Re: Similiarities to Western Electric
« Reply #7 on: May 04, 2021, 10:05:33 AM »
Hah! I think for marketing, the saying might be restated as: baffling with detail (no sale) vs. dazzling w/ BS (great success!)   :D
Derek
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Roon Intel NUC ->  Yggdrasil DAC -> BeePre (w/ BeeQuiet and EML 300B)  -> Kaiju (w/ DCFil and EML 300B) or Stereomour II (2A3 [EML Mesh] and 45 Conversion [EML 45B])  -> Audeze LCD4

Offline Paul Birkeland

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Re: Similiarities to Western Electric
« Reply #8 on: May 04, 2021, 10:34:36 AM »
This is an approximation of how I'm doing it.  Most of the bias voltage appears at the grid from a negative supply and the CCS between filament and ground provides the rest. This will keep the tube optimally biased until it's super dead. This thing is going to eat 300Bs though!
Paul "PB" Birkeland

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Offline Doc B.

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Re: Similiarities to Western Electric
« Reply #9 on: May 04, 2021, 11:35:42 AM »
Which half of the 1/2 6CK4 are you using, the plate or the cathode?
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Offline Paul Birkeland

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Re: Similiarities to Western Electric
« Reply #10 on: May 04, 2021, 11:39:38 AM »
This probably makes more sense!
Paul "PB" Birkeland

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Offline Thermioniclife

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Re: Similiarities to Western Electric
« Reply #11 on: May 04, 2021, 05:18:08 PM »
Hey PB, while most of this is beyond me I am curious regarding the last schematic you posted. I see that there are 2 Od3's in series,
I am wondering why this is used, is it because of keeping the cathode current under control by sharing the load between 2 vr's or perhaps the the the high B+ supply? Also I see that you are not using the internal jumpers pins 3 and 7 as a safety or is that not present to keep the sch. simplified? Just askin. Thnx.
Lee R.

Offline Paul Birkeland

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Re: Similiarities to Western Electric
« Reply #12 on: May 04, 2021, 07:00:08 PM »
The 0D3s just reduce the voltage going to the 6CK4 to keep it from drawing tons of current across the cathode choke.  If you pull the 0D3s out, the 6CK4 won't conduct, nor will it pass signal, and the grid bias at the 300B will become more negative, so the jumpers aren't so necessary.  The schematic I posted was something I drew out in a couple of minutes and is nowhere near a finished design, more of a sketch of what such an amp might generally look like.
Paul "PB" Birkeland

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Offline Gerry E.

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Re: Similiarities to Western Electric
« Reply #13 on: Yesterday at 12:52:11 PM »
To get 20 watts out of a 300B, you'd have to run it at maximum voltage and near maximum plate dissipation and drive the grid positive.  This is a decision that will come at the expense of tube life.

Just a thought - Maybe they know that their new graphene coated 300Bs are up to the task?  When and if the amp ever becomes available I could easily see some type of disclaimer that ends with "... only when used with genuine current production Western Electric 300Bs".   

Gerry

Offline Paul Birkeland

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Re: Similiarities to Western Electric
« Reply #14 on: Yesterday at 01:30:33 PM »

Just a thought - Maybe they know that their new graphene coated 300Bs are up to the task? are in the business of selling 300Bs.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man