[seaverd]

Any suggestions for a good headphone amp.  I would love a nice DIY project?

[seaverd]

One more question Mouser and Digikey are out of this cap until mid March:

EKY-500ETC220ME11D

Any suggestions on where I can buy a couple of them?

Thanks,

Dan

[rhing]

What is this cap for? No one has recommended it for the TDA7297.

[seaverd]

rhing,

I copied it and pasted it from the first post in this build guide.  Is there a typo...its the third cap listed in the parts list.

[devinkato]

Is it okay to use an unregulated DC power supply with this?

This one in particular - http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2102094_-1

[Folsom]

Is it okay to use an unregulated DC power supply with this?

This one in particular - http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2102094_-1

Yes. You just don't want to use things too close to 18v, because if you get too much of a spike it might fry it.

[mboxler]

Is it okay to use an unregulated DC power supply with this?

This one in particular - http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2102094_-1

Hmmm...that looks like a 2.1 x 5.5 mm plug.  I think you want a 2.5 x 5.5 mm.

I go this one...works very well.

http://www.ebay.com/itm/290727815800?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Mike

[S Clark]

Took the TDA7297 over to a friends place today.  This has a Panasonic and two Sprague orange drops, but still has the rectifier, the led, and the pot- powered by a 7AH battery.  I blindfolded him and we went back and forth with his Rogue integrated.  We agreed that the Rogue had more musical vocals with greater depth, but gave the nod to the 7297 on imaging.  Bass accuracy and quickness were deemed a tie.  Needless to say, he was stunned when he saw what was competing so closely with his $1200 amp- and not exactly pleased.  I've got another one that I've still got to mod and compare again.  Fun, fun, fun. 

[Folsom]

So far they do better with non-phono sources as far as I can tell.

I am going to swap in an Elna Silmic 11 for next to chip duty. Might have to be smaller, so more off board or mounted under.

When comparing mine to a Bryston 3BSTT, it was pretty shocking. And thats before yanking a series cap, MOV, and replacing the tinsel cable on the SMPS that was used. The bass was slightly shy, and overall lacked a little authority, but it was more accurate with some stuff. The highs on the Bryston lack some timbre that small circuits seem to keep a bit better. (Or higher voltage)

[devinkato]

I just completed the mods - Holy moley, night and day difference.

Bass is MUCH more present, and tighter.  The amp runs much cooler as well.  I didn't notice any large change to mid/high clarity personally, but it really feels like it's extending 2 octaves lower than it did at stock configuration.  I really feel like we're cheating the system with this little guy.  Unbelievable value.

[elb]

Hello all,
just an update.

waiting for Nichicon Muse BP 1 uF to arrive,in the meantime I have reinstated the Jantzen Superior Z caps.(no hum issues this time)

Removed the volume pot.The volume is now controlled  with a Silk TVC.

Just a personal observation.
when people report on modifications to this amp and indeed all other types of cheap ebay amps,the first comment is usually on how the bass has improved.
Sure bass is important but what about the whole spectrum.To my old ears the mids and highs remain the same,no improvement to be had.

One more thing,I have added an off board power supply capacitor bank.

Thank you.

[devinkato]

Sure bass is important but what about the whole spectrum.To my old ears the mids and highs remain the same,no improvement to be had.

I agree with you.  The bass improvement to me was important because I felt that it was rolling off too early in the stock configuration.  By improving the bass, the mods help bring it to sound more "flat". 

The mids/highs remaining the same isn't a bad thing - in the stock config, they're pretty darn good - everyone (myself included) praises the imaging of the amp, which is mainly a function of the mids/highs.

[Folsom]

Don't forget that input caps take a minute (or 20hrs) to burn in.

[devinkato]

Just ordered a stepped attenuator with surface mount resistors, I don't think it comes with through pins, so I'll have to mount it off board.

What do you guys recommend for hookup wire?  I'm really trying to avoid any inducted noise or loops.

Thanks!

[Folsom]

For signal go small, 28ga.

Rhing likes some shielded stuff, check the 3116 topic for info.

[devinkato]

Thanks salis - have you ever tried using reclaimed cat5 cable?  That's the only stuff I have on hand that approaches 28 ga.

[rhing]

For signal go small, 28ga.

Rhing likes some shielded stuff, check the 3116 topic for info.

On one of my TDA7297 amps, I used 0.5mm (24AWG) Mundorf Silver-Gold wire twisted in a pair from the RCAs to the Alps Blue Velvet volume pot. I have also used Mil Spec 22AWG Teflon-insulated solid core Copper wire twisted in a pair in my other TDA7297 amp with good results. My runs are short, so I'm not too concerned about inductance.

I've used shielded hookup cables in my Class D amps to avoid any RFI. This is not a concern with the TDA7297 chip amp.

[Folsom]

Cat5 is great if you can keep it short.

[devinkato]

Cat5 is great if you can keep it short.

Cool, this is going in a VERY small enclosure that will also house the capacitor buffer that you outlined in one of your previous posts.  All internal wire runs will be very short.

Should be a real giant killer.  I still think that there could be a good application for these in an active car audio setup as well.

[Folsom]

What are you going to power it with? It has basically no filtration. Sure the Power cap is very low ESR, but unlike big giants in AB world, there is no filtration, or RF rejection of any sort.