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Posted new design: "Jonokuchi" destop amp

post #1 of 45
1/31/11 at 6:02pm
Thread Starter 

jono_front.jpg

 

jono_inside.jpg

 

People have asked me for a DIY tube headphone amp design that will drive small speakers (like computer speakers) for quite a while.  I just posted such a design, called "Jonokuchi" (Jonokuchi refers to the beginner ranking of sumo wrestlers).

 

Details are here:

 

http://www.pmillett.com/Jonokuchi.htm

 

It's a simple amp, nothing revolutionary, using 13EM7 tubes.  It can be built point-to-point, or I have a PCB available that makes it an easy build for a newbie.

 

Pete

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post #2 of 45
1/31/11 at 8:09pm

It looks like a fun and easy build, particularly with the PCB.  Thanks for sharing it.

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post #3 of 45
1/31/11 at 10:57pm
I like those graphs!

Thank you for another great project Pete - you've done so much to help our hobby along.

Now... do I have a spare $200 around here somewhere....
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post #4 of 45
2/2/11 at 2:49pm

Thanks for sharing this amp, it looks like a fun build!

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post #5 of 45
2/7/11 at 11:37pm

Perfect for what I need :)

 

I've decided to make this my first build.  I ordered the Edcor transformer package you set up on their website.  Right now I'm going through the BOM, and found a minor mistake and also had some questions.

 

For part "Resistor, 220k ohm 2W small film", the quantity is 2 but should be 3 I believe, as you have it listed for R4/R6/R7.  There are also two small price miscalculations on your BOM: 1. you listed the price of the PCB as $30 instead of $40, and 2. on the speaker binding posts you put quantity 2 but didn't extrapolate the price accordingly. :)

 

For "Resistor, 330 ohm 2W small film", Mouser has a minimum order limit of 2000 for part number "660-SPR2LT521R331J" .  I see you have these resistors starred with the comment that others can be used.  I'm guessing there should be no problem if I use the alternative "594-5083NW330R0J" which is a metal film resistor, even though the rest of the resistors I have in my cart for this amp section are carbon film?  Or would I need to use purely metal film resistors in this case?

 

Once the above concern is confirmed or denied, I will make the mouser project public and post it here with in stock parts for people who wish to build this cool little amp. biggrin.gif

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post #6 of 45
2/8/11 at 10:45am

One can mix various resistor brands & types freely as long as power ratings (and in some extremely high voltage amps voltage ratings {does not seem to apply here, and almost never in a cathode resistor, just general FYI}) are respected. 

 

The KOA SPR carbon films in the BOM are pretty pimp, and the amp looks like sex with the green resistors on the red PCB. Perhaps a call or email to mouser is in order? They sell most other values in that line as singles, and 330ohms is not exactly an unusual value.

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post #7 of 45
2/8/11 at 12:02pm

You can always pay more for the same resistors by buying from the boutique sellers.  Kiwame is the same as the Koa SPR series.  There are a lot of good 2W resistors out there so the sky really is the limit. 

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post #8 of 45
2/8/11 at 1:01pm

Looks great Pete, you can count me in to put one together :)

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post #9 of 45
2/9/11 at 10:25am

Pete, unless the board has changed from what you have on the site, you may want to switch these on the BOM:

 

C9+C10 to C5+C6 (0.1uF 630V)

C14+C15 to C9+C10

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post #10 of 45
2/9/11 at 12:51pm
Thread Starter 

 

Quote:
Originally Posted by n3rdling View Post

 

For part "Resistor, 220k ohm 2W small film", the quantity is 2 but should be 3 I believe, as you have it listed for R4/R6/R7.  There are also two small price miscalculations on your BOM: 1. you listed the price of the PCB as $30 instead of $40, and 2. on the speaker binding posts you put quantity 2 but didn't extrapolate the price accordingly. :)

 

For "Resistor, 330 ohm 2W small film", Mouser has a minimum order limit of 2000 for part number "660-SPR2LT521R331J" .  I see you have these resistors starred with the comment that others can be used.  I'm guessing there should be no problem if I use the alternative "594-5083NW330R0J" which is a metal film resistor, even though the rest of the resistors I have in my cart for this amp section are carbon film?  Or would I need to use purely metal film resistors in this case?

 

You are correct, the 220k resistor should be 3 pcs. - thanks, I will fix the BOM.  On the 330 ohm, the part you mention is fine. 
 

Quote:
Originally Posted by nikongod View Post

 

The KOA SPR carbon films in the BOM are pretty pimp, and the amp looks like sex with the green resistors on the red PCB. Perhaps a call or email to mouser is in order? They sell most other values in that line as singles, and 330ohms is not exactly an unusual value.


I agree!  I guess I didn't notice the minimum was a full reel at Mouser! 

 

Quote:
Originally Posted by spritzer View Post

You can always pay more for the same resistors by buying from the boutique sellers.  Kiwame is the same as the Koa SPR series.  There are a lot of good 2W resistors out there so the sky really is the limit. 


 Parts Connexion has the "Kiwames" in almost every value, so that is an option to keep all the same resistor type.
 

Quote:
Originally Posted by HiGHFLYiN9 View Post

Pete, unless the board has changed from what you have on the site, you may want to switch these on the BOM:

 

C9+C10 to C5+C6 (0.1uF 630V)

C14+C15 to C9+C10


You are correct.  I thought I fixed that, but maybe I forgot to push the update to the web site.  Sorry for the confusion!
 

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post #11 of 45
2/9/11 at 3:23pm
Thread Starter 

OK, the BOMs should be fixed.  Freaky - my local copy had been updated, but for some reason when I published the website updates these files did not get replaced, even though a newer copy existed in my local web.  So I manually deleted the files on the server and re-published.

 

Guess I have to enter the current century and dump FrontPage one of these days.

 

Pete

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post #12 of 45
2/9/11 at 3:26pm

Wow, nice design.  I just added this to the list.  Definitely interested and I love how accessible you made it for DIYers of all levels.

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post #13 of 45
2/11/11 at 10:28am

Looks great!   Thanks for sharing yet another neat amp!

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post #14 of 45
3/6/11 at 5:31am

Has anyone built this amp yet? I would very much like to know how it sounds!!!

 

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post #15 of 45
3/6/11 at 7:55am

This has now been added to my list to build.  I like the fact that it is right in a good price range with the PCB.  I will most likely do it p-t-p though.  I just like the freedom of lay out that way. 

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