[I.Greyhound Fan]

I know this is an old thread but I need some help.  I have a Class D Audio CDA-254 kit amp that I want to upgrade.  It has the 300VA torroidal transformer and I want to upgrade to the Antek 400VA.  Does any one know which model that I need as there are several with different specs?  The amp just does not seem to have enough drive for being 250wpc. It did not seem to drive a pair of MMG's that well.   It has been sitting in my basement not being used.  My Adcom AVR sounds better.

Also, I have been thinking about swapping out the 4 resistors, 2 on each board for Carbon Riken or Audio Note Tantalums to see if I can warm things up a bit.  I doubt that they would change the sound but it is worth a try.  I used these resistors in the Pass B1 preamp that I built and they sure made things sound warm  and smooth.

Thanks for the help!

Larry

[mboxler]

Do you know the output voltage of your current tranny?  This one is 34 volts, which will give you around a 48 volt supply.  Seems they have changed the amp names...the CDA-254 is no longer listed.  The CDA-250 must be the new CDA-254???

http://www.antekinc.com/as-4434-400va-34v-transformer/

Mike

[I.Greyhound Fan]

My current transformer is an AN-3332 300VA and the outputs are as follows-

115v
115v
32v
32v
18v

So I assume I need a 400VA with the same voltage?

I found these 2-

http://www.antekinc.com/as-4435-400va-35v-transformer/

http://www.antekinc.com/as-4434-400va-34v-transformer/

[mboxler]

The new CDA-250 requires +- 42 to +- 52 volt supply.  I assume the old CDA-254 is the same.

Your 32 volt tranny will rectify to 32 * 1.414 or around +- 45 volts.  A 34 volt tranny will give you around +- 48 volts.

I like to split the difference, so the AS-4435 would work.  The AS series is shielded, the AN series is not.  Don't know if the makes a difference.

It would be interesting to check the output voltage from your current setup, to make sure it is around 45 volts DC.  Home voltages do vary!

Hope that helps!

Mike

[I.Greyhound Fan]

Thanks for the help.  I will go with the AS-4435.  Hopefully the upgrade will yield a little more oomph!

The amp can definitely use a little more gain as well.

Has anyone changed any of the Resistors or Caps?

[wushuliu]

Thanks for the help.  I will go with the AS-4435.  Hopefully the upgrade will yield a little more oomph!

The amp can definitely use a little more gain as well.

Has anyone changed any of the Resistors or Caps?

Hm, I dunno 5.5A cap for your Maggies sounds kind of low from what I've read about them. I seem to recall them needing more power earlier in the thread. I have a feeling you need either a MUCH bigger transformer or a higher power CDA amp, or both. Probably need to beef up the caps too if you have the stock ones.

[I.Greyhound Fan]

Hm, I dunno 5.5A cap for your Maggies sounds kind of low from what I've read about them. I seem to recall them needing more power earlier in the thread. I have a feeling you need either a MUCH bigger transformer or a higher power CDA amp, or both. Probably need to beef up the caps too if you have the stock ones.

Do you think jumping up to a 500VA or 600VA transformer would help? 

[Nick77]

Its important that you have the larger power supply or buy the blank and add your own to increase capacitance. TSHA Pannys.

http://www.classdaudio.com/power-supplies/upgrade-power-supply/

[wushuliu]

Do you think jumping up to a 500VA or 600VA transformer would help?

yes. also what Nick said. the power supply is the weak spot for cda amps. even my old two ways benefited when I had those amps.

[I.Greyhound Fan]

If I wanted to replace the caps in my current power supply, what values do you recommend?  Are there any caps with a warmer sound for this application?  I have no problem soldering.  Or I just may buy the bare power supply board for $40.

[wushuliu]

If I wanted to replace the caps in my current power supply, what values do you recommend?  Are there any caps with a warmer sound for this application?  I have no problem soldering.  Or I just may buy the bare power supply board for $40.

I used 6800uf panasonic thsa. 8200 as well I think. Been awhile. As long as they are rated for your voltage get as much as you can. I think I had 90k at one point. The board is easy to desolder iirc.

[wushuliu]

The cda site offers 60k I see so that makes me feel a little better about my recommendation as I try to be conservative. Do at least 60.

[I.Greyhound Fan]

Would the 6800uf 63v caps be ok with this Antek transformer for the CDA or do I need lower voltage caps?

http://www.antekinc.com/as-4435-400va-35v-transformer/


https://www.banzaimusic.com/Panasonic-TSHA-6800uF-63V.html

[srb]

That's the maximum voltage for the capacitor, there isn't a problem using one rated higher and in fact is good practice to de-rate them for safety margin and longevity.

Steve

[wushuliu]

Would the 6800uf 63v caps be ok with this Antek transformer for the CDA or do I need lower voltage caps?

http://www.antekinc.com/as-4435-400va-35v-transformer/


https://www.banzaimusic.com/Panasonic-TSHA-6800uF-63V.html

Yes 63 is fine.

[I.Greyhound Fan]

Much thanks!

Larry

[GRACE RUBY]

It might also be related to an appliance with a motor that cycles on and off, like a refrigerator or an air conditioner.

Steve

good advice, these amps are as sensitive as any out there, I know there are many kinds all under the heading of Class d, mine is the 12 pounds and  only 25 watts per channel kind and I had a lamp next to it with incandescent bulb and it made the amp buzz, and traditionally that is a great thing, good equipment is very sensitive, mine is a sigma 7th order 1 bit, with over 2 million x over sampling,  if anyone knows about it please pm me.

PS a iron choke on the power chord really effects the sound for the better, smoother, sometimes

Ruby

[GRACE RUBY]

To me an amp should not be treated like that. It should just work with a simple power chord. To buy other treatment products, I also not sure whether it works, could end in give more problems than solving it.

Hi WIM

my cardas power line turns my D amp into a whole new machine, there is a difference anyone can hear.

[GRACE RUBY]

I'm from Malaysia, currently having a pair of Wharfedale Denton 80th Anniversary, amplified via Marantz PM6005, distort when volume pass 12 o'clock, also feel that the speakers need more juice, thus I have ordered SDS-400C since got offer price, I'm using JDS Labs ODAC, no preamp yet, any to recommend? What happen if I drive directly using ODAC?

the Denton's have a very layed back sound, try thermostat cable (solid 5 wire) non OFC, this is very fast wire
and good luck

[wim1983]

Hi guys, recently doing some experiments, and cut off some wires, but dunno how to put back, I would like to configure to use RCA single ended input only, but I'm not able to figure how to, here's the pic, it seem there is no jumper to set RCA or Balanced XLR? Hmm, it takes me sometimes but still cannot figure out how the RCA/Balanced XLR switch works, there are 4 wires initially from the switch, white yellow white yellow, the connections very complicated even I check back my pictures, do I need to install jumper ports on nearby the bridge port?






Can give me clear details how to use RCA input only? For max gain, I just need to desolder left and right gain jumper parts, then put a jumper right?