NEWAS - Grid and Anode Chokes

SET

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SET

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Grid and Anode Chokes
Jan 9^th, 2010 at 5:39pm

Hello everyone!

Well, One day I got to reading about the benefits of grid chokes.

#1 Low impedance to ground meaning less noise.

#2 Better recovery from clipping as the cap can discharge faster due to the low DCR.

#3 The generation of a substantially larger load for less distortion.

#4 Of course this was the big one for me greater dynamics, sheer punch! �

Little did I know just how much they can effect the sound!

Especially in an SE amp like mine.

My amps 811-10's are hard to drive because they run in Class A2 and the 811 has a 39k grid resistor so when the grid goes positive it pulls current.

I use a 6EM7 tube to drive it with which it is essentially a 6SL7 and a 10 watt power triode with a 700 ohm plate impedance which is darn near like a 300B only this is used as a cathode follower to drive the 39k grid resistor.

Now with the new grid choke we are talking about 100's of thousands of ohms while still providing a low DCR path for the grid current.

Another issue I had with the Cathode drive was the loading I use which is a 12K cathode resistor which is much of a load.

Now with the Anode Choke, the Cathode Drivers loading is 100,000 ohms plus.

Whats the significance of this all?

Well, It was jaw dropping to say the least!

Everything was virtually improved!!!!!

More space, air, resolution, decay's, image stability and coherency, impact!

The impact just totally blew me away, If you thought my amps were gutsy before your not going to believe them now!

The sound stage is larger, virtually huge, really huge, going well past my side walls.

Layering is nothing short of phenomenal.

Resolution of information, harmonics, textures, body, image outlines were greatly enhanced. They were good before but they are just so more real like.

I was afraid I might not like what I heard "Tonally" boy was I wrong!!!!

Talk about sweet! These amps now have more warmth at start up then with several hrs of listening. And the top end is silky smooth!!! Oh My God smooth!!! yet there is more information.

The Bass lines are dramatically enhanced. I hear more pitch definition along with longer decays, the skin of the kettle drums from Master and Commander were absolutely spectacular.

The amps clipping characteristics were enhanced. I used the Titanic sound track to investigate the enhancement and wow!

When clipping occurs in my amps, it has a hang time to a certain extent! Well that hang time was dramatically reduced. This helps with the amps integrity of the music.

Overall its as though the amps have a far greater sense of ease and extension of notes I especially hear this with the bass, its as though some of that subterranean stuff is now even more evident to the point of feeling it in my chair on recordings that were not formally known for it! Down right spooky stuff!

Also its one thing to have deep bass but I swear it seems wider and more defined from any part of the sound stage, holy cow!!!

Below are the chokes, the grid is the small one and the anode is the larger one.

Also here is the latest full picture of one monoblock

SET

Oh Yeah! The price for all this performance! Can you believe $150??? The improvements are worth ten times or more easily to my ears!

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forch God Member Offline I love YaBB 1G - SP1! Posts: 1037 Gender:	Re: Grid and Anode Chokes Reply #1 - Jan 10^th, 2010 at 7:15am Hey Dan, keep sharing your upgrades - very interesting and you can put it terms a lay man / dummy like me can understand! Nice work. F rch
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Re: Grid and Anode Chokes
Reply #2 - Jan 10^th, 2010 at 10:59am

Thanks, Forch!

Its an astonishing upgrade � Wink

More can be done to the amps supply to get it quieter and even more dynamic, as if the thing isn't dynamic enough already! It will kill many SS amps that I have heard watt for watt with out so much as a blink IMO.

I have a 50 watt single stage SET amp on the drawing board that I'd like to get built after some small projects to take care of around here.

The 50 watter is intended to redefine the word "Dynamic" Remember that Tom Evans amp you heard in NY!

Well my design by the #'s could be 3-4 times The Linear A's Dynamic Conductance �depending on the Linear A's primary impedance of its output transformers.

One thing for sure its getting Grid Chokes!

I'm getting to think this combination of an Anode choke and Grid Choke is even more potent than an inter-stage transformer!

SET

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forch God Member Offline I love YaBB 1G - SP1! Posts: 1037 Gender:	Re: Grid and Anode Chokes Reply #3 - Jan 10^th, 2010 at 11:08am Yep, I keep my eye open for the Evan's amp on Agon, but they are few and far between and still keep their price. Out of my range, unfortunately. How are you going to do a single stage in the 50 watter? F rch
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SET

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Re: Grid and Anode Chokes
Reply #4 - Jan 10^th, 2010 at 12:11pm

forch wrote on Jan 10^th, 2010 at 11:08am:

Yep, I keep my eye open for the Evan's amp on Agon, but they are few and far between and still keep their price. Out of my range, unfortunately.

How are you going to do a single stage in the 50 watter?

F Cheesy

rch

Well, the gain or Mu of an EL84 tube is about 425 which is 2.5 times more than any EL34 or 6550, KT88 and so on.

Now when you Parallel tubes the gain increases. with ten tubes in Parallel thats a Mu 241 with no feedback. 50 watts across a 5k primary is 500 VAC of signal. With the Mu of 242 you need just 2 volts in! this doesn't account for transformer losses but its close enough! And if I want I can have a driver stage that I can bypass to allow for the single stage operation. Easily driven by most line stages.

The Key to Tom Evans amps dynamics is the single-ended loading that creates large dynamic conductance numbers. Thats (Trans-conductance of a tube X Load) when you parallel its additive.

Most PP tube amps have a conductance number of 5-10 with a few going higher. But noting like the Tom Evans amp!

Which would be something like 4 paralleled EL84's = 40,000us or .04x a load of say 2500 ohms which would be a dynamic conductance of 100!

Well with ten tubes its something like .100 X 5000 in my design or 500 for a dynamic conductance. this can go higher with the Svetlana SV83 which has a trans-conductance of 18,000us Its the tube that Decware has made popular in some of his amps! He also uses high loads for superior dynamics.

Imagine 300ma of current response from a fraction of a volt!

I have an old console SET amp from yrs ago! that I reverse engineered! It was very strange in its design! I believe it used this very principle for creating a two watt amp that literally blew away my old HK Citation Amp that was dynamic enough to keep up with a Classe power amp! That two watts had more punch than my HK enough that pictures on my apartment walls would move from the impact created by it!

I never investigated it on the bench to see if it was really linear but I noticed it had a circuit to enhance loading for the single pentode tube.

Funny I have discussed this concept with a friend perhaps 10 yrs before I ever saw the Linear A amp!

Benefits are very low distortion even lower than many PP amps!

You can forget any side effects from paralleling the tubes because your going to here more information than what is typically heard with a level of dynamic impact that is absolutely scary!

SET

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SET

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Re: Grid and Anode Chokes
Reply #5 - Jan 12^th, 2010 at 4:25pm

I just ordered my second set of grid chokes for my input stage!

I just got done with a listening session and I'm still blown away with these things, There should be some improvements from using them even on the input of the amp especially where Miller Effect Capacitance is at the tubes maximum for my amps due to the C4S current source maximizing the tubes gain.

I just shook my head, As my Jenifer Warns Hunter CD which I have on Black Memorex and have listened to this recording for nearly 20 yrs now sounded so huge that I'd swear it sounded as though I had an extra 10 feet of of apparent sound stage! There is just no question about it!!!

The sense of space is just so easy to hear, every part of the sound stage has a level of definition I just haven't heard before. Speakers are even pulling off a larger disappearing act, images are further behind the speakers as well.

SET

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forch God Member Offline I love YaBB 1G - SP1! Posts: 1037 Gender:	Re: Grid and Anode Chokes Reply #6 - Jan 13^th, 2010 at 1:11pm Dan, thanks for the explanation. Wonder why more manufacturers go that route, being that the EL84 is cheap and plentiful....
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SET

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Re: Grid and Anode Chokes
Reply #7 - Jan 13^th, 2010 at 4:13pm

forch wrote on Jan 13^th, 2010 at 1:11pm:

Dan, thanks for the explanation. Wonder why more manufacturers go that route, being that the EL84 is cheap and plentiful....

Yeah Forch, The EL84 is very special and a few manufactures have taken advantage of it!

Like this Lectron which I had the opportunity to at least see! It got a Class A rating from Stereophile Magazine!

I think it was some $3000 20yrs ago.

Lets not forget Raggy's Mahi's or the Stingray!!

My gut feeling over the Tom Evans Linear A's is that his amp likely surpasses most EL84 designs and many other tube PP types for dynamics and distortion as Tom's amp is lower than many PP types and funny how it is a SET design!!!!

Think paralleling all those Pentodes is going to seriously hinder the sound?

Think about all those SS amps with 10-30 paralleled devices!

If you think there is, read this! a preamp from CJ with 10 paralled triodes/channel!

http://www.stereophile.com/tubepreamps/8/index.html

I wish I could of heard the Tom Evans with you!

I probably would of been even more motivated to build my project earlier!

Also I will be using grid chokes with my 10 tube PSET EL84 Monoblock.

I often refer to as my 10 Man Amp! I can't imagine the dynamics it could generate! �Its funny how much odf an emotional effect that can have on me. Don't get me wrong I still want everything else to go with it and in my experience with high loading,high dynamic conductance it often does come!

Other News on my home front! New Midrange diaphragms are coming this week which I talked to the Engineer that had them developed for his business he told me that he has been ecstatic over them because the manufacture was able to eliminate the high frequency bounce back �common in all Klipsch mid-range drivers, the resulting sound is very smooth extended! They should be here by the weekend!

I am just pumped over all this stuff!!

SET

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dirtyragamuffin God Member Offline Vacuum tubes for all! Posts: 1861 Oshkosh B'Slosh Gender:	Re: Grid and Anode Chokes Reply #8 - Jan 14^th, 2010 at 12:51pm Great stuff, SET! Your amps always sounded wonderful--what you're describing sounds phenomenal!
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SET

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Re: Grid and Anode Chokes
Reply #9 - Jan 14^th, 2010 at 2:59pm

dirtyragamuffin wrote on Jan 14^th, 2010 at 12:51pm:

Great stuff, SET! �Your amps always sounded wonderful--what you're describing sounds phenomenal!

Thanks Raggy,

Yeah the amps are just scary unreal!!!!! yet they are in no way taken as far as they can go, yet I can't imagine them getting better but I know its possible yet!!!

My new Klipsch Mid-range Diaphragms are here and I'm hoping for an even smoother response as I was told these new diaphragms are one of the technically best in contrast to what Klipsch has been using! Both past and present!

I don't know fast I can get them in but I'm working on them now!!!! Construction is a little different then I envisioned but if they do what Bob Crites says they do I will be just ecstatic!!!

Working on them now !!!!!

And Raggy, I know how you love huge soundstages but you ought to here the size of mine now!! Also What makes it real scary to me is the level of definition from all parts of it! The lateral impact is one of the shocking areas as well!

So Raggy, If you can get away I'd love to give you a demo day or night!!!, I also have some new recordings with some of the best darn bass I have ever heard! And talk about fast and tight!!! I had a Bass Player here for a demo and he introduced me to these new recordings that are just awesome!!!

Also I can't remember if you heard my Burson Discrete Op Amp-Sony CDP Mods with the Sony's supply increased by 10x with Muse electrolytic �caps feeding the Burson's! its just a monster now just strutting its stuff in this system! �

Cheers

Dan

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tomelex Senior Member Offline Audio is what you hear... not what you see Posts: 348 Watertown Gender:	Re: Grid and Anode Chokes Reply #10 - Jan 15^th, 2010 at 11:01pm SET's on fire! � Somebody find an extinguisher! You da Maann! � I ain't sure what dynamic conductance is but I want some! � Rock on! � t melex
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SET

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Re: Grid and Anode Chokes
Reply #11 - Jan 17^th, 2010 at 7:17am

Yeah, I do get exited don't I � Roll Eyes

�I had "No Regrets" here yesterday for 5 hrs, said its the best midrange that he has heard from these yet � Tongue

I can't complain myself �

he said the level performance and system resolve was pretty amazing so the new midrange diaphragms are a complete thumbs up Wink

along with the other mods.

Later

SET

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Rooze God Member Offline Posts: 1756	Re: Grid and Anode Chokes Reply #12 - Jan 17^th, 2010 at 8:35am SET gets my gold star award for outstanding contributions to this website. Even though I don't participate much these days (in the hobby and in the forum), I still enjoy checking in every once in a while, and SET's enlightening posts and the enthusiastic way in which they are delivered always cheers me up no end!
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dirtyragamuffin God Member Offline Vacuum tubes for all! Posts: 1861 Oshkosh B'Slosh Gender:	Re: Grid and Anode Chokes Reply #13 - Jan 17^th, 2010 at 3:04pm Amen to that! I may not always understand what half of it means but I really enjoy reading about your audio escapades, SET! Makes me wish I was an EE...
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SET God Member Offline SET Posts: 807 Gender:	Re: Grid and Anode Chokes Reply #14 - Jan 17^th, 2010 at 7:39pm Hey Thanks Guys! I never got a gold star before!
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