[knestle]

Hi, Guys,

I'm the new kid on the block.
I'm 62, semi-retired, deaf in one ear (it's a monophonic world for me), totally ignorant in the area of electronics, and about to start my first ever electronics project.

I'm collecting parts for a cmoy amp in the little Hammond enclosure.

My questions (only two at the moment) are about upgrades to the basic design.


Question 1.

I want to add the TLE2426 rail splitter.

All I've been able to find are seveal schematics that show the TLE2426 in the circuit with the ground going 'somewhere'. Where is 'somewhere' ?

I am guessing that I just use one of the long pads that run the length of my board and connect the ground of the TLE2426 and all other grounds to the same pad. Good guess?


Question 2.

I would like to add buffers (BUF-634). In all of Tangent's articles (a gold mine for newbies like me) he specifies the 8 pin DIP, but due to limited space available I am looking at the TO-220 five pin version.

Is there any reason why the TO-220 style would not be acceptable? Would I need heatsinks with these (my guess is no)?

Question 3. (yeah, I know I said only two)

Would either or both of these upgrades have side effects that need to be addressed?

If these subjects have already been mulled over and beaten to death, I apologize (I've looked everywhere I could think of, and have found nothing), please point me to the right thread or FAQ.

TIA

Ken

 

[Zemo]

Hey man! Excellent to see an ambitious newb!

1- yes, you're correct, the ground (labeled output on the TLE2426 schematic) does get tied to one of the longish pads on the board, as does anything else that needs to be tied to ground.

2- the TO220 style would be just fine, as long as you get all the pins conncted to the right things. And no, no heatsink will be necessary.

3- there are certain side effects...the TLE2426 has a bit of current draw, and the buffers ahve a lot. This means greatly reduced battery life...as long as you're prepared to deal with that, you should be fine! To limit the current draw of the buffer, choose which value resistor you want to use for bandwidth limiting wisely! Tangent reccomends 200ohm for one buffer..but if you're going portable, I wouldn't feel bad about having it as infinite (no resistor, no jumper) to conserve battery life. Also, in the enclosure you mentioned, only one battery will be feasable, so choose capacitor values accordingly.

And speaking from experience, the smallest hammond, at about the size of a pack of cigarettes, is extremely difficult to cram everything in to. I'd suggest getting the enclosure with the same hight and width, but more depth. part# is 1455C1201. It'd end up looking a lot like this:

Hope this helps!

-Z

 

[skyskraper]

do you reckon the mico cmoy would fit in to that smallest hammond case? im adding a mini volume pot and a "mute" button to it. no need for a power switch as the 3.5mm sockets i am using are switched.....

 

[Zemo]

yeah, I bet you could make tangent's micro cmoy layout fit in the smallest hammond. I made my cmoy layout fit in a hammond just fine, so it is doable.

About the switched 3.5mm jacks...you sure you won't be tying something to V+ or V-? That is, are you sure that all of the connections used to pass power through arn't going to be touching left, right, or ground channels? Cause that could get messy....

-Z

 

[knestle]

Quote:

Originally Posted by Zemo And speaking from experience, the smallest hammond, at about the size of a pack of cigarettes, is extremely difficult to cram everything in to. I'd suggest getting the enclosure with the same hight and width, but more depth. part# is 1455C1201. It'd end up looking a lot like this: Hope this helps! -Z

Thanks for the confirmations, Zemo.

Actually, I already have the 120mm box

. I knew 80mm was not going to be enough, but 120mm is esthetically unacceptable to me, so I'm going to trim it to 100mm (go figure). That extra 20mm makes all the difference!

Have fun

Ken

 

[MD1032]

My buddy tpg fit my Meta42 with socketed op-amp, jacks and stuff, two 8-pin BUF634's, the TLE2426, and the 9-volt battery in my hammond enclosure (the real small one, it's an excellent enclosure...amazingly solid!).

Of course, he just happens to be a master at getting things like this in small places.

 

[bubbagump]

Quote:

Originally Posted by knestle I want to add the TLE2426 rail splitter. All I've been able to find are seveal schematics that show the TLE2426 in the circuit with the ground going 'somewhere'. Where is 'somewhere' ?

It took me an extraordinary amount of searching to really understand how to use the rail splitter. The lights didn't go on until I found these cmoy pictures. The second picture down is the TLE2426. And then looking at the board layout of the meta42 here, I finally understood the purpose and wiring of the rail splitter. Looking at this picture the green is the virtual ground loop. I'm still fuzzy though how the wiring of the TLE2426 ground works with relation to the virtual ground on the cmoy.

 

[skyskraper]

zemo: yup it seems that im ok on that front. if it do turn out that it ties everything together then ill junk that idea and move to a pot with switch in it or to a mini slide switch... i think i should have plenty of room in the smallest hammond for all that

i just need to find some appropriate hardware so i can attach a little keyring or loop that will let me attach it to a lanyard. having a mute switch is gonna be useless if i have it in my pocket and it keeps triggering!!!

 

[knestle]

Hey, Z man,

I don't know if this is what you had in mind but:

Look at one of those two-key-ring connectors that uses a push-button to allow the unit to seperate in the middle.

If you use just the push-button half you could put it in a hole

in the Hammond enclosure. A very strong and secure attachment, and easily removable.

Ken

 

[skyskraper]

ooh wicked idea. ill defn look in to that one. the lanyards i have, have a locked hook on them so its really easy to get on and off as it is.

lemme know how u go adding the rail splitter, im new to this as well but am about to order some to add to my cmoys in progress (hehehehe 4 on the go atm

)

 

[knestle]

skyscraper,

Sorry I got my posters confused.

Has this been covered (in what thread or FAQ?) / is this possible:

An onboard circuit for recharging li-ion 9V without removing them from the case.

Ken

P.S. All this got started because I bought an Archos Studio 10 to listen to for 4.5 hours a day. It works fine but can't put out enough volume in the noisy van I drive on my part time job.

 

[skyskraper]

hmm i was sure id seen a circuit somewhere around the place that had provisions for charging 9v batteries.

id just cheat and get one of those nine volt battery snaps and solder a dc plug onto it. have a dc socket on the amp wired in to the battery and put the 9v snap onto the 9v bit of your charger. im not even sure if it would work. hehehe sorry i can't be of much help im just a newb too