choke question

rockstah · Post by **rockstah** » Thu Apr 12, 2007 1:25 am

what is the purpose of the choke?

im trying to figure what 3h to 10h means. how does say a 3h and 10h compare in tone and or what are they both doing or not doing compared to each other?

Mark

novosibir · Post by **novosibir** » Thu Apr 12, 2007 4:49 am

Trying to get it on the point, but w/o becoming scientifical:

In combination with the following filter cap, a higher inductivity choke is filtering more of the remaining ripple out of the DC voltage, supplying the screen grids, as a lower inductivity. So the power stage does add less of the odd order harmonics to the sound, especially when driven hard, what makes it sound smoother.

A power stage with a lower inductivity choke is adding more odd order harmonics to the tone, what makes it sound more raw or crude.

But we're familiar with some odd orders in the tone and our ears would miss it, if they suddenly aren't there.

Although, what sounds 'better' to us or to our ears is depending on the whole amp, the voltages, the characteristics of the OT & speakers, aso. and last but not least on your personal taste.

It's pretty like the taste of a soup - some salt & pepper (ketchup, chili or whatever) you'd need in it, that it's tasty for you - but have you put in too much or you forgot to put it in, you won't like it.

Larry

BTW: A higher inductivity choke helps to make the amp less ghosting w/o make its playing feel stiffer.

Wicksy · Post by **Wicksy** » Thu Apr 12, 2007 7:10 am

Damn, its good to have you around here Larry. That explains it better than any book i've read. Cheers!

rockstah · Post by **rockstah** » Thu Apr 12, 2007 11:21 am

thanks Larry so the 3h would be more agressive than a 10h. but the 10h would be less stiff to play. smoother. the 3h adds more odd order harmonics than the 10h. in other words a 3h would be better than a 10h for say something like Van Halen tone?

guitronics · Post by **guitronics** » Mon Jun 04, 2007 8:03 am

There are people in the electronics design world that do nothing but develop power supplies ....for a living.

The "H" Stands for "Henries" and gives a value to the Inductance of the choke.

The Inductance is how well the Choke filters out ripple (AC) in the power supply. More "H" gives you more Filtering...less Power line hum.The 10 H is much more effective than the 3 H...assuming they both handle the same current.

Inductance means roughly that you "Induce" a voltage and current into a magnetic core.In short, the magnetic properties aid in smoothing the AC artifacts into purer DC.

There are also Filter (Electrolytic) Capacitors,Resistors, maybe regular capacitors in the Power supply.Sometimes there's also a "Regulator"...a Solid - State (Semiconductor) device that holds the voltage to a certain value.

Tube amps are very primitive in their power supplies, in fact - if most modern circuits used these power supplies, they would be unreliable or not even work. The cool thing about these power supplies is that they are perfectly suited to vacuum tube amps for guitar....adding compression effects, sag, etc.

In a high -end Tube Power amp for listening to recorded music,these P.S.'s would introduce distortion.Not Good for Audio reproduction, but great for guitar, since distortion is wanted! That's why at least 1/2 of the "Electric Guitar Sound" is the FX,Amp,and Speakers.The Guitar is the other 1/2.

ToneBone · Post by **ToneBone** » Thu Oct 11, 2007 4:11 pm

On a related note, is there a correct way to install a choke? That is, are the two wires comming from each end of the choke's winding so there's only one correct way to wire it? There's normally two black wires but I've never known if it matters which way it's wired in the amp.

bluze81 · Post by **bluze81** » Thu Oct 11, 2007 9:55 pm

I have tried the 5h,3h,7h 10h, chokes, for rock tones I really like the 3h, its raw and sounds more agressive than the others, the 5h sounds more compressed but good, the 10h I have is a Merc, and is super smooth,never tried a 20h.

5150loveeddie · Post by **5150loveeddie** » Thu Oct 11, 2007 10:43 pm

How about the Ma rating of a choke? Will it change something in the tone? I just got a 5H 150ma instead of the more ususal 100ma, trying to illiminate more the ghosting and it seems more high mid heavy, something in the mids are not like ususal OR is it? Might have to try a 100ma rated choke there and see the difference...

novosibir · Post by **novosibir** » Fri Oct 12, 2007 8:29 am

ToneBone wrote:There's normally two black wires but I've never known if it matters which way it's wired in the amp.

Doesn't matter! If it would matter, the cables would have different colours.

Larry

novosibir · Post by **novosibir** » Fri Oct 12, 2007 8:34 am

5150loveeddie wrote:How about the Ma rating of a choke? Will it change something in the tone? I just got a 5H 150ma instead of the more ususal 100ma, trying to illiminate more the ghosting and it seems more high mid heavy, something in the mids are not like ususal

When you crank the amp, so that due to the enhanced output power and enhanced (screen's) current through the choke it's reaching the rated for current, the choke is driving into saturation and its inductivity drops down.

So your 5H choke suddenly will be only a 1H coke, or a .05H choke, depending on the current draw - and your sound then is different.

Larry

5150loveeddie · Post by **5150loveeddie** » Fri Oct 12, 2007 2:22 pm

novosibir wrote:
5150loveeddie wrote:How about the Ma rating of a choke? Will it change something in the tone? I just got a 5H 150ma instead of the more ususal 100ma, trying to illiminate more the ghosting and it seems more high mid heavy, something in the mids are not like ususal
When you crank the amp, so that due to the enhanced output power and enhanced (screen's) current through the choke it's reaching the rated for current, the choke is driving into saturation and its inductivity drops down.

So your 5H choke suddenly will be only a 1H coke, or a .05H choke, depending on the current draw - and your sound then is different.

Larry

Fantastic Larry thx man!!!

Post by **Brian Wallace** » Fri Oct 12, 2007 5:28 pm

Doesn't matter! If it would matter, the cables would have different colours.

Some do have different wires, one red and one black, but it still doesn't matter.

novosibir · Post by **novosibir** » Fri Oct 12, 2007 6:08 pm

Oh yes, shure! I just forgot to mention this

Larry

guitronics · Post by **guitronics** » Fri Oct 12, 2007 9:40 pm

Don't wanna step on toes.....

The Choke is part of the "Cleanup Circuit" that takes the rectified DC with garbage in it and makes it more like the pure DC you'd get from a battery.

We all want to get the garbage out!

Here's the parts in a typical tube amp power supply: Step up and Down Transformer, Diodes,Electrolytic Capacitors, maybe non - Electrolytic Capacitors, Resistor(s), and a Choke.Some designs are infinitely more sophisticated.

The goal of the parts between the Transformer and Amplifier is to eliminate 60 Hz hum, 120 Hz hum, and multiples of these frequencies.

An unplugged guitar with the volume turned up on an amp is the sound of the hum we're trying to eliminate.

Amp manufacturers put in the cheapest parts which they deem are "Acceptable" in order to make profits, and to compete with other makers.

H = henries, and indicates the filtering capacity of a choke. At Audio frequencies, the more henries, the better....until you reach the point of diminishing returns.

Henries is the result of how many and what type of steel laminations present, and how many turns of wire.

The Current rating is based on how many turns of what size wire used.

More wire requires more laminations in order to get more windings on the core.

Unless you're doing a new design,I'd stick with the stock choke's ratings.

If there were significant variations in sound,believe me; the amp makers and transformer/choke makers would be promoting different models.

Here's a link to a wiki >

http://en.wikipedia.org/wiki/Choke_(electronics)

novosibir · Post by **novosibir** » Fri Oct 12, 2007 10:51 pm

A good explanation, guitronics!

And don't worry! There's nothing in it, what could step on somebodys toes

Larry

Metropoulos Forum

choke question

choke question

Power Supply Choke(s)

choke question