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Old 22nd October 2011, 07:07 PM   #981
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Because reusing the transformer you already have would save some money.
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Old 22nd October 2011, 09:33 PM   #982
Rush is offline Rush  United States
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Quote:
Originally Posted by woody View Post
Because reusing the transformer you already have would save some money.
Antek has a 15+15 volt AC transformer rated at 300VA for $36 plus $11 shipping in the USA.

Antek - AN-3215

I sold the old transformer with bridge and caps on eBay for $25. Also sold the input boards to a guy in Australia for $25. I may have been lucky, but the transformer was a wash with the fees and all.
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Old 24th October 2011, 03:02 AM   #983
fab is offline fab  Canada
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Default Class A higher current

Quote:
Originally Posted by Rush View Post
Yes FAB, that's what I did. Worked out very well. I use it as a tweeter amp, running 17.5 VDC on each rail.
Hi Rush

Ok for a tweeter amp where the power requirements are reduced a lot...
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Old 2nd February 2012, 02:35 AM   #984
WSJ is offline WSJ  United States
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Troubleshooting a Hafler HD-220 board can be difficult due to limited access to the solder side of the board. Quick Disconnect Terminals will fit at the bottom of the board by drilling a second hole 0.200 form the existing wire hole. Smaller connector socket and pins can be used for the input. This allows the board to be removed form the amp and folded out form heat sink. A current limited lab power supply can be used if a ground jumper is added form the power supply ground to the input ground.

There is a possibility of problems due to contact resistance, however, this mod will provide better access for troubleshooting and testing.

TERMINAL QUICKFIT .052"DIA .250"
http://www.keyelco.com/pdfs/M60/M60p53.pdf
Digi-Key - 1287K-ND (Manufacturer - 1287)
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Old 10th February 2012, 11:59 PM   #985
pongagt is offline pongagt  United States
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I'm recapping a Smart version DH-220 and i am undecided on what caps to use for the 1000pF and below caps. Mouser has Kemet PFR series polypropylene 5% caps in all the right values including the .39uF and .005uF. I have never heard of them and i don't know how they would be for audio use. The Smart version already has some of the mods listed on this thread but i thought it would be a good idea to refresh the caps. I'd appreciate if anyone can comment on these caps or what brand to use for the referred values.
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Old 15th February 2012, 04:53 AM   #986
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Quote:
Originally Posted by pongagt View Post
I'm recapping a Smart version DH-220 and i am undecided on what caps to use for the 1000pF and below caps. Mouser has Kemet PFR series polypropylene 5% caps in all the right values including the .39uF and .005uF. I have never heard of them and i don't know how they would be for audio use. The Smart version already has some of the mods listed on this thread but i thought it would be a good idea to refresh the caps. I'd appreciate if anyone can comment on these caps or what brand to use for the referred values.
Please provide a link to this Smart DH-220, schematics, pictures of your progress, etc.

Thanks in advance.
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Old 15th February 2012, 03:20 PM   #987
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http://www.smartdevicesinc.com/pdf/ta120-ta242.pdf
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Old 15th February 2012, 04:58 PM   #988
pongagt is offline pongagt  United States
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Quote:
Originally Posted by jackinnj View Post
Thanks for the link. I didn't know that existed.

My amp is the TA242 which is a Hafler DH-220 modded by Smart Theatre Systems for movie theaters. I bought one for $100 best offer on Ebay. You can get good deals on these because most people don't know anything about them and they don't have the external looks of a home amplifier. The beauty is in the inside of the amp. My amp had a loud hum in one channel when i received it but it just turned out to be a wire that came off the volume control. My neighbor has around 13 of these so i will be able to compare a modded amp to a stock amp. I plan on comparing it to my Bryston 4B SST amp on my living room home theater system with Paradigm Studio 60's. Eventually the amp will be used in my bedroom as a vintage 2 channel system with a Tandberg 3008A preamp and not so vintage Ascend Acoustics Sierra 1nrt monitors.

The Smart TA242 amp has a torroidal transformer, heavy duty bridge rectifier, heavy duty power cord (still only 18awg) and power switch, main capacitor circuit board, and input volume controls. The boards are PC19 revision C. They also have a connector on each board so the boards can be swapped out by removing 4 screws. This was very convenient considering the amps were used for movie theaters and it made it very easy to swap out a dead channel. Many theaters are installing more powerful sound systems so some of these amps are popping up on ebay.

I have changed the terminal strips to rca jacks and binding posts.
Changed the stock 10,000 mfd caps to 18,000 mfd Nippon caps.
Upgraded to a higher rated bridge rectifier that i bought from the same seller on Ebay as the capacitors.
Installed a 14awg power cord and i am going to upgrade the rest of the 18awg wire that feeds the capacitor board.
I have started collecting capacitors for doing a complete swap out with Elna Simic II 100 mfd and Wima, Panasonic, Dayton, or Kemet polypropylene films caps depending on what is available.

The linked picture is the stock TA242.

Click the image to open in full size.
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Old 16th February 2012, 02:21 AM   #989
eyoung is offline eyoung  United States
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the prior post had 3 o/p pairs not a dh220...some pic and descriptions...
E
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Old 16th February 2012, 02:33 AM   #990
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Quote:
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the prior post had 3 o/p pairs not a dh220...some pic and descriptions...
E
Probably a Hafler P230 or something.
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