Thank you panomaniac!
Those are the first polys I've ever owned so you can Imagine my surprise when I got them expecting them to fit in that tiny case.
I was originally going to use some black gates but got talked out of using them. If I had it to do over I would just go ahead and put them in instead. Oh well, I think they add character to the amp sitting on top.
I put a Neutrik 1/8" stereo plug in so I could use that curly plug that came with the SI to hook up my MP3 player without the need for rca adapters and such.
I was powering it off a 10 amp regulated supply but noticed a low frequency hum. I think its do to the fact the supply is very old and only has a half bridge rec on the trafo. In the top pic its being powered off of a 17Ah lead acid.
I think the final setup is going to be an all battery powered setup with a Sony DiscMan with digital out, a battery powered NO DAC, and the battery powered SI.
Those are the first polys I've ever owned so you can Imagine my surprise when I got them expecting them to fit in that tiny case.
I was originally going to use some black gates but got talked out of using them. If I had it to do over I would just go ahead and put them in instead. Oh well, I think they add character to the amp sitting on top.
I put a Neutrik 1/8" stereo plug in so I could use that curly plug that came with the SI to hook up my MP3 player without the need for rca adapters and such.
I was powering it off a 10 amp regulated supply but noticed a low frequency hum. I think its do to the fact the supply is very old and only has a half bridge rec on the trafo. In the top pic its being powered off of a 17Ah lead acid.
I think the final setup is going to be an all battery powered setup with a Sony DiscMan with digital out, a battery powered NO DAC, and the battery powered SI.
KT said:
I used some epoxy/plastic dipped 2.0 uF poly's that are a little wider than the board (but not very tall). I then mounted them in the through-hole pads that were originally for the L/R post-volume control input. With the "inputs" hanging off the other side of the board, I soldered my input leads there.
Note that doing it this way requires you to remove the 10k resistors between the input and ground and remount them before the caps. Furthermore, you then have to solder wire bridges to the old capacitor input pads.
I actually went overboard and removed the high-pass RF filter as well.
The end result is decent, but I don't think that it's necessary. I noticed that my DC offset increased quite a bit (+55 mv in one channel, -33 in the other -- the stock amps have 3-5 mv offset in either channel). This may be due to RF. That's why I'm going to advocate soldering BG's on to the pads, since the bg's are so small that you probably won't lift the pads using them.
I'll try to take some pictures of my modded SI when I have some spare time.
Mike
I replaced the stock cap with a 1500uf 16v generic I had laying around and it seems to work just fine.
Its hard to tell with all that stuff jammed in that tiny case, but I used very small wire to go from the cap leads right to the business end of the input resistor.
I ended up with 0mv offset on the left and only 3mv on the right
.
MEXXX
Its hard to tell with all that stuff jammed in that tiny case, but I used very small wire to go from the cap leads right to the business end of the input resistor.
I ended up with 0mv offset on the left and only 3mv on the right
.MEXXX
MEXXX,
That's a really cool idea to go for the minature configuration w/ caps on top. Half the fun of reading these posts is to see other people's great creative ideas regarding the enclosures. The mini design really brings home that "David vs. Goliath" feel to the project. It'll be fun for you to see the wide eyes of your uninitiated friends.
That's a really cool idea to go for the minature configuration w/ caps on top. Half the fun of reading these posts is to see other people's great creative ideas regarding the enclosures. The mini design really brings home that "David vs. Goliath" feel to the project. It'll be fun for you to see the wide eyes of your uninitiated friends.
time to add to the list of SI recasings! here's some photos of my amt aluminum chassis (i still need to solder the guts to the inputs and outputs) and power supply together. each secondary of the transformer will eventually power a t-amp in a bi-amped configuration
here are the other photos
An externally hosted image should be here but it was not working when we last tested it.
here are the other photos
well, i worked on it all day and managed to finish the amp about 6 hours ago i've been listeing to cd's and watching north carolina beat illinois since then. here she is in all her glory!
it may look normal on the outside, but it has special guts.
squeezed in amt's already miniscule chassis is an LT1083 low dropout regulator with all the fixings. the 15vac transformer secondaries equates to about unregulated 22.4vdc at the filter caps. this is fed to the regulator which drops it to any voltage between about 1.25v and 15v based on the resistance of the potentiometer. it also features 120hz ripple rejection with a 33uf cap on the adjust pin, a potection diode between the input and output, and two 3300uf panasonic fc series caps in parallel on the output (the most i could fit in the chassis!). to accomodate the point-to-point wired regulator circuit i had to "mount" the board sideways behind the volume pot. this not only saved space but placed it closer to the regulator, inputs, and outputs.
the volume pot is a 50kohm alps blue velvet, the rca jacks and binding posts are from parts express, the dc power jack and plug are from switchcraft, and the wiring is all upgraded to 22ga utilizing only the necessary traces. i also used kemet ceramic 0.01uf 50V axial X7R differential caps on the outputs.
i've been listening to it with the regulator output at a rock solid 13V and it sounds great. the TA2024 chip gets much warmer at 13V than it does at 12V, but not burning hot. vocals and cymbals sound incredible. bass is also improved but it's hard to say how much because my definitive speakers don't go very low. my favorite cd so far has been August and Everything After by the Counting Crows. I also liked a couple of Sting's songs (i.e. If I Ever Lose My Faith In You and Fields of Gold... yes, i like some of his stuff too
)
a few more photos are in here as well.
i've been listeing to cd's and watching north carolina beat illinois since then. here she is in all her glory!
An externally hosted image should be here but it was not working when we last tested it.
it may look normal on the outside, but it has special guts.
An externally hosted image should be here but it was not working when we last tested it.
squeezed in amt's already miniscule chassis is an LT1083 low dropout regulator with all the fixings. the 15vac transformer secondaries equates to about unregulated 22.4vdc at the filter caps. this is fed to the regulator which drops it to any voltage between about 1.25v and 15v based on the resistance of the potentiometer. it also features 120hz ripple rejection with a 33uf cap on the adjust pin, a potection diode between the input and output, and two 3300uf panasonic fc series caps in parallel on the output (the most i could fit in the chassis!). to accomodate the point-to-point wired regulator circuit i had to "mount" the board sideways behind the volume pot. this not only saved space but placed it closer to the regulator, inputs, and outputs.
the volume pot is a 50kohm alps blue velvet, the rca jacks and binding posts are from parts express, the dc power jack and plug are from switchcraft, and the wiring is all upgraded to 22ga utilizing only the necessary traces. i also used kemet ceramic 0.01uf 50V axial X7R differential caps on the outputs.
i've been listening to it with the regulator output at a rock solid 13V and it sounds great. the TA2024 chip gets much warmer at 13V than it does at 12V, but not burning hot. vocals and cymbals sound incredible. bass is also improved but it's hard to say how much because my definitive speakers don't go very low. my favorite cd so far has been August and Everything After by the Counting Crows. I also liked a couple of Sting's songs (i.e. If I Ever Lose My Faith In You and Fields of Gold... yes, i like some of his stuff too
)a few more photos are in here as well.
BWRX said:well, i worked on it all day and managed to finish the amp about 6 hours ago
An externally hosted image should be here but it was not working when we last tested it.
it may look normal on the outside, but it has special guts.
An externally hosted image should be here but it was not working when we last tested it.
squeezed in amt's already miniscule chassis is an LT1083 low dropout regulator with all the fixings. the 15vac transformer secondaries equates to about unregulated 22.4vdc at the filter caps. this is fed to the regulator which drops it to any voltage between about 1.25v and 15v based on the resistance of the potentiometer. it also features 120hz ripple rejection with a 33uf cap on the adjust pin, a potection diode between the input and output, and two 3300uf panasonic fc series caps in parallel on the output (the most i could fit in the chassis!). to accomodate the point-to-point wired regulator circuit i had to "mount" the board sideways behind the volume pot. this not only saved space but placed it closer to the regulator, inputs, and outputs.
the volume pot is a 50kohm alps blue velvet, the rca jacks and binding posts are from parts express, the dc power jack and plug are from switchcraft, and the wiring is all upgraded to 22ga utilizing only the necessary traces. i also used kemet ceramic 0.01uf 50V axial X7R differential caps on the outputs.
a few more photos are in here as well.
I'll be going with something similar in one of AMT's chassis Probably a LM338 based regulator @12.5 or so volts on Tangent's "Tread" board and an external 15v/2.5 amp wall-wart.. I'm going to be using a Noble pot instead of the Alps Blue Velvet (I have a bunch of these nice 10k noble's that are Alps BV fighters), and I'll be combining it with all the mod knowledge I've acquired from my adventures along with Pano's and other's.
Looks good, though. I'm sort of surprised you didn't use the chassis as a heatsink instead, though.
I've just got to finish up my order with AMT
Mike
Top notch!
Well, I must say, there is some top notch modifying going on here.
Good work all around.
Like the new amp, Mike. Very clean wiring job, looks like you really know what you're doing. I like the PSU, too.
A couple of questions, comments.
Very clever idea on the dual power supply to power an active system.
Where do did you fond these panny filter caps? I've been using nichicons, which are very nice but don't have the handy screw terminals like yours do.
It looks like you have a heat sink on your voltage regulator. Did it get warm? Mine did not, but was sinked to the case. Maybe you should get a heat sink on that Tripath chip. Running as hot as they do can't be good for long life. It "seems" to me that the sound quality goes down a bit as the heat goes up.
I'm using a little stick-on heat sink that came from ebay, I think someone here posted it. Just right for the chip. Only $1.
Good work all around.
Well, I must say, there is some top notch modifying going on here.
Good work all around.
Like the new amp, Mike. Very clean wiring job, looks like you really know what you're doing.
I like the PSU, too.A couple of questions, comments.
Very clever idea on the dual power supply to power an active system.
Where do did you fond these panny filter caps? I've been using nichicons, which are very nice but don't have the handy screw terminals like yours do.
It looks like you have a heat sink on your voltage regulator. Did it get warm? Mine did not, but was sinked to the case. Maybe you should get a heat sink on that Tripath chip. Running as hot as they do can't be good for long life. It "seems" to me that the sound quality goes down a bit as the heat goes up.
I'm using a little stick-on heat sink that came from ebay, I think someone here posted it. Just right for the chip. Only $1.
Good work all around.
those panasonic computer grade caps were actually from digikey. manufacturer part #EEG-A1G223FGE, digikey part#P10078-ND. i found places with higher value caps for about a third the price but they were larger cans and had no other information about them other than capacitance and voltage rating.
that little heat sink on the regulator is part of one that used to be for an old pentium processor. i hacked it to fit inside the chassis. the regulator does get warm because it has to drop about 10 volts. the heat sink and the chip still only get fairly warm to the touch, regardless of how loud (reasonable levels) or long i've been playing music. i wanted to sink the regulator to the case but the case is already grounded due to the dc power jack and the metal back of the regulator case is at the output potential. i don't have any insulating thermal pads either, so i just hacked an old cpu heatsink. i did also make a small one for the ta2024 chip but didn't know how to hold it on the case. are the little heatsinks you guys use are held on with just a piece of regular double sided tape or a small dab of thermal paste or something else?
that little heat sink on the regulator is part of one that used to be for an old pentium processor. i hacked it to fit inside the chassis. the regulator does get warm because it has to drop about 10 volts. the heat sink and the chip still only get fairly warm to the touch, regardless of how loud (reasonable levels) or long i've been playing music. i wanted to sink the regulator to the case but the case is already grounded due to the dc power jack and the metal back of the regulator case is at the output potential. i don't have any insulating thermal pads either, so i just hacked an old cpu heatsink. i did also make a small one for the ta2024 chip but didn't know how to hold it on the case. are the little heatsinks you guys use are held on with just a piece of regular double sided tape or a small dab of thermal paste or something else?
Most double-side tape is a foam-core and will only insulate. I dont suggest it.
I picked up a set of copper "ramsinks" and a batch of "Arctic Silver" thermal adhesive. ...something like 99% conductivity efficient. Pricey tho, I think I paid $14 shipped for the epoxy and 4 ramsinks, but will take care of all my tripath cooling woes for my next few amps.
...will post pictures tonight of the ramsinks and my source as well.
--BillyM
I picked up a set of copper "ramsinks" and a batch of "Arctic Silver" thermal adhesive. ...something like 99% conductivity efficient. Pricey tho, I think I paid $14 shipped for the epoxy and 4 ramsinks, but will take care of all my tripath cooling woes for my next few amps.
...will post pictures tonight of the ramsinks and my source as well.
--BillyM
Thanks for the part # on those panny caps. Digikey, of course. I have such a hard time navigating the Digikey catalog.
Good idea not to ground the regulator, keep away from ground loops! You should be able to find an insulating pad over on Digikey, just don't ask me where they are... I grounded my regulator as it is the only negative connection to the case.
As for the heat sinks, I got them from "wluk" on eBay. Nice little guys with thermal tape already on them. Cheap too. They are called a "ramsink", made for video boards.
Good idea not to ground the regulator, keep away from ground loops! You should be able to find an insulating pad over on Digikey, just don't ask me where they are... I grounded my regulator as it is the only negative connection to the case.
As for the heat sinks, I got them from "wluk" on eBay. Nice little guys with thermal tape already on them. Cheap too. They are called a "ramsink", made for video boards.
panomaniac said:Thanks for the part # on those panny caps. Digikey, of course. I have such a hard time navigating the Digikey catalog.
Good idea not to ground the regulator, keep away from ground loops! You should be able to find an insulating pad over on Digikey, just don't ask me where they are... I grounded my regulator as it is the only negative connection to the case.
As for the heat sinks, I got them from "wluk" on eBay. Nice little guys with thermal tape already on them. Cheap too. They are called a "ramsink", made for video boards.
Best place I found for TO-220 insulating pads was from Allelectronics.com.. They had kits (pad + all mounting hardware) for like $0.33 each or something. If you need a wallwart to power your regulator, they're a great source for those as well.
Digikey is actually pretty easy to use if you know how to enter the right stuff on their search engine. If you want a real pain in the ****, try using Mouser/newark .. That's just like smashing your skull against the wall.
Of course, I have some of their paper catalogs, which are pretty handy.
Digikey is my favorite parts supplier to buy from. Mouser is pretty good too, and they at least carry the Vishay Dale RNC series along with some other good stuff (good quality1/8" jacks, and cheap quality IC sockets).
It's funny how much of the computer overclocking stuff has been permeating into audio in various ways (heatsinks/heatsink compound, enclosures, etc.).
motherone said:
the thing is the LT1083 only comes in a P or K package. the ones linear sent me are TO-3P which is larger than the TO-220 package (gotta love free samples though!). i haven't seen any place that has TO-3P insulating pads but then again i haven't looked that hard.
motherone said:
i couldn't agree more. although it could be much better, it is better than mouser/newark unless you know exactly what you're looking for.
some more news for you fellow t-amp fiends out there. i got a temp probe for my DMM and measured the operating temperature of the SI TA2024 chip and the LT1083CP regulator. interestingly enough, with unregulated 23V in, 13V regulated out, and the amp playing at a moderately loud level, both the chip and regulator heatsink hover around 52ºC which are acceptable temperatures for both parts. the ambient temperature in the room was 25ºC and the air was pretty still even though my window was open.
i should be testing my amplifier's performance this week as well. i just have to get access to the proper equipment and figure out how to use it.
i should be testing my amplifier's performance this week as well. i just have to get access to the proper equipment and figure out how to use it.
output cap question
Hello, I'm new to the forum. Thanks to all for the generous sharing of information!
Being ignorant of electronics and clumsy with soldering, I wasn't planning on doing any fancy modding—just change the connectors, wiring, pot, and batteries. Near the end of project, after a successful test run and a martini, a drop of solder landed right on output capacitor c20. While cleaning up the carnage, the tiny cap came right off.
Any advice on what I should do? Re-attach the original? Upgrade it and its partner? Is polarity an issue? My speakers are 15ohm, 95db speakers if that matters.
Thanks, Lokitas
Hello, I'm new to the forum. Thanks to all for the generous sharing of information!
Being ignorant of electronics and clumsy with soldering, I wasn't planning on doing any fancy modding—just change the connectors, wiring, pot, and batteries. Near the end of project, after a successful test run and a martini, a drop of solder landed right on output capacitor c20. While cleaning up the carnage, the tiny cap came right off.
Any advice on what I should do? Re-attach the original? Upgrade it and its partner? Is polarity an issue? My speakers are 15ohm, 95db speakers if that matters.
Thanks, Lokitas
Well you've got yourself in a mess there.
C20 is one of the output filter caps, I think, being fed from L6.
Tripath call for a 0.47uF in this spot, but the Sonic version is not marked, so we don't know what the value is.
Polarity should matter here, but I don't know how to tell with those little SMD caps. Anyone? It may a stacked film cap and thus not polarized. I sure don't see any markings.
You could replace C20 and its brothers. While your at it, replace the coils and the power supply cap. The results should be great, but it's probably more work than you were counting on.
C20 is one of the output filter caps, I think, being fed from L6.
Tripath call for a 0.47uF in this spot, but the Sonic version is not marked, so we don't know what the value is.
Polarity should matter here, but I don't know how to tell with those little SMD caps. Anyone? It may a stacked film cap and thus not polarized. I sure don't see any markings.
You could replace C20 and its brothers. While your at it, replace the coils and the power supply cap. The results should be great, but it's probably more work than you were counting on.
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