Tracopower AC-DC transformers.

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jasonallenh

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I've seen these a few times, and used them with decent results...

http://www.tracopower.com/products/tmp.pdf

Could I get some opinions on these? I know for high-draw items, they won't cut it... but the +/- 15V supply seems like it could be great for first projects. An EQ/Compressor running off a 15 volt supply seems like it would be perfectly happy!

Discuss? Shun? I like you guys  ;)
 
With efficiencies in the 75-80% range, they are switchmode supplies.  Fine if they are well filtered to keep any noise out of the audio (good modern ones are).  Beyond that it depends on pricing and availability.

Complaints?  Smallest 48v supply is 310ma - enough phantom power for a 24 channel console.  Dual supplies only go to +/-15 (no 18 or 24).  No supply has +/-15v and 48v
 
Plastic casing? I'd leave them away of my stuff, I should test if I would connect my stuff via a wire to it, maybe they are fine, but I'm a little worried with the plastic casing. I could have some fan with ±15V 1A or ±15V 0.5A +5V 3A for some mixed projects...

JS
 
1 % Ripple  :eek:

That is equivalent to 40 dB Ripple Rejection.
Good ol' LM7815 has a minimum Ripple Rejection of 62 dB...

These modules will require serious filtering for audio.

Best,
Carsten
 
culteousness1 said:
1 % Ripple  :eek:

That is equivalent to 40 dB Ripple Rejection.
Good ol' LM7815 has a minimum Ripple Rejection of 62 dB...

These modules will require serious filtering for audio.

Best,
Carsten

Whoah!  Missed that spec when I scanned the data.
 
mjrippe said:
Complaints?  Smallest 48v supply is 310ma - enough phantom power for a 24 channel console.  Dual supplies only go to +/-15 (no 18 or 24).  No supply has +/-15v and 48v

Yep, even with my somewhat limited knowledge, I knew phantom 48V was out of the question. Compressors/EQs may pull it off, but definitely not suitable for pres or tube stuff.

culteousness1 said:
1 % Ripple  :eek:

That is equivalent to 40 dB Ripple Rejection.
Good ol' LM7815 has a minimum Ripple Rejection of 62 dB...

These modules will require serious filtering for audio.

Best,
Carsten

Obviously there is a price to be paid for 'cutting corners,' but to a newcomer to DIY, do you feel that the less-intensive PSU build and perceived safety from this make it worth the price of more caps?
 
culteousness1 said:
1 % Ripple  :eek:
Apples.

culteousness1 said:
Good ol' LM7815 has a minimum Ripple Rejection of 62 dB...
Oranges.

culteousness1 said:
1 % Ripple [...] is equivalent to 40 dB Ripple Rejection.
No, it's not. "Ripple and noise", as specified in the Tracopower datasheet, are purely referred to the output. "Ripple rejection" is how much an AC component at the input is attenuated (rejected) by the time it gets to the output. Old school linear regulators like the 7815 tend to have their ripple rejection specified for 120Hz, as that is the dominant frequency component you need to deal with after a full-wave rectifier. As the 7815 datasheet shows, ripple rejection drops off fairly rapidly for higher frequencies, mostly because of the regulator's limited loop bandwidth.

Whether the Tracopower unit's output spectrum will be more or less harmful to a given audio circuit than a transformer/rectifier/7815 tag team is hard to guess without further details. With common SMPSes I would expect most of the ripple energy to be at and above the switching frequency. The TMP modules seem to have a fixed 100kHz switching frequency, which eases filtering requirements.

JDB.
[some audio circuits are more willing to detect and rectify HF signals into the audio band, too]
 
jasonallenh said:
I've seen these a few times, and used them with decent results...

http://www.tracopower.com/products/tmp.pdf

Could I get some opinions on these? I know for high-draw items, they won't cut it... but the +/- 15V supply seems like it could be great for first projects. An EQ/Compressor running off a 15 volt supply seems like it would be perfectly happy!

Discuss? Shun? I like you guys  ;)
SMPS have been given a bad rap in audio, and indeed there are some awful ones around, particularly in wall-wart format, but now there are many rather decent SMPS that can be used for audio with just a simple LC filter.
I would say for DIY, their only justification is size and, to a minor extent, heat.
But for something that is sold to a customer, the safety certification is highly valuable.
 
abbey road d enfer said:
joaquins said:
Plastic casing? I'd leave them away of my stuff, I should test if I would connect my stuff via a wire to it, maybe they are fine, but I'm a little worried with the plastic casing.
Why?

I'm wondering the same thing... if it's in a properly shielded case, how's that any different than any other internal PSU?
 
I don't know if it's internally shielded, if it is there should be no problem. Small "lossy" transformers working at HF may be a problem to have close to some sensitive nodes, while output noise may be filtered without much problem with one or two LC stages the EMI takes a bit more work to get rid of.

JS
 
I haven’t tried the TracoPower AC-DC power supplies you mentioned but I have tried their DC-DC converters. I must admit that I was sceptical because I have always have bad experiences with SMPS but they are actually great for entry level DIY projects.

I am planning on using THIS in my new Eurorack live rig. The ripple/regulation specs are even better than the AC-DC parts and they have no high voltages (just a laptop charger input.) there are also higher current versions but at this price and size I think they are great!
 

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