Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: daveyajd on May 25, 2019, 11:06:01 am

Title: Choke size
Post by: daveyajd on May 25, 2019, 11:06:01 am
I am collecting parts for my mMatchless Lightning build and I’m wondering what size choke I would need.
In a previous post sluckey said he has used a Hammond 193B which is 12H 100ma 155 ohms.
I’m wondering if I need to go that big or if something a little smaller (cheaper) will work and still sound like it should. How do I know what size is enough?


Aaron
Title: Re: Choke size
Post by: shooter on May 25, 2019, 12:38:34 pm
looking at this schematic;

https://el34world.com/charts/Schematics/files/Matchless/Matchless_lightning.pdf
the choke is AFTER the power tubes so it doesn't "see" the big current load.  just a worse than napkin guess 50mA rating should be ok, the "bigger" the henrys the better PS filtering for pre and G2 of the power tubes
Title: Re: Choke size
Post by: sluckey on May 25, 2019, 01:10:41 pm
The Hammond 193B has a much higher current capacity than is needed for the Lightning. The only reason I used it is because it was sitting in my parts cabinet doing nothing.  :icon_biggrin:
Title: Re: Choke size
Post by: daveyajd on May 25, 2019, 02:12:26 pm
Awesome. Thank you all so much. I will look at something a little smaller.
I see a Hammond 157J that has 10H 65ma 205 ohms. That seems pretty close while still having plenty of H.
Is there a number that I want to be close to as far as Henries or resistance?
I read post on here that referenced Merlin’s book and said something like: the sum of the two caps x H = anything over 200 being acceptable.


Aaron
Title: Re: Choke size
Post by: vampwizzard on May 25, 2019, 10:45:52 pm
I used the small fender style choke from the store here on my recent matchless and it worked very well.
Title: Re: Choke size
Post by: dpm309 on May 27, 2019, 12:47:22 pm
I built a Lightning 15 a few years ago and used a Hammond 158M, 10H, 100mA, 195 ohms. Sounds great!
Title: Re: Choke size
Post by: daveyajd on May 27, 2019, 02:54:20 pm
That’s great! Did you build your lightning pretty much to spec as far as filtering? I will pick something up around those choke sizes.


Going to try to get fancy with this build and do a lighted logo and maybe light the faceplates up too. We’ll see.


Aaron
Title: Re: Choke size
Post by: dpm309 on May 27, 2019, 06:45:13 pm
Yes, used the spec filtering for the Lightning. I did add a "cut" control and a boost switch but other than that, it is similar to the Lightning.
Title: Re: Choke size
Post by: vampwizzard on May 27, 2019, 07:01:34 pm
Yes, used the spec filtering for the Lightning. I did add a "cut" control and a boost switch but other than that, it is similar to the Lightning.

+1 on converting MV to Cut or adding a cut control to these amps. When you set it, start with volume, then tone, then cut. makes it a lot easier to dial it in without getting that ice pick thing.
Title: Re: Choke size
Post by: daveyajd on May 27, 2019, 07:45:18 pm
I did have a cut control initially because I was basing my layout partly on Sluckeys version. But I took it out. Guess I need to add it back in.  :icon_biggrin:
It is set up as a pot/cap connected right off the master pot, right? I was also wondering about other types of MV because I’ve heard the crossline style isn’t the best. What othe types have you all used in this amp?  How did you wire the boost switch in and do you find it useful?


Aaron
Title: Re: Choke size
Post by: vampwizzard on May 27, 2019, 08:40:39 pm
Theres some stuff on this forum and the guitologist on YT just did a video explaining the types of MV's and their application. Youre correct about the location. You can view the cut controls off vox's for more inspiration.