$175 Class D amp--120 wpc

nodiak · « **Reply #2300 on:** 20 Dec 2010, 04:49 am »

Anyone added a volume pot to CDA-254? If so would really appreciate pics to help with wiring.
I have 10K Bourns and 25K from ebay (used for B1).
Don

Mass. Wine Guy · « **Reply #2301 on:** 20 Dec 2010, 05:22 am »

The amp arrived yesterday and I hooked it up with a Beresford 7520 DAC in the mix. I'm going to remove it to see how things sound without it. I need to do a lot more listening before I judge this amp completely. It images very well, good sound stage. I'm not positive that I like the overall sound as well as with my Adcom 535, but this is a very tentative observation.

I also have a hum since installing the amp. A cheater plug did not remove it.

jtwrace · « **Reply #2302 on:** 20 Dec 2010, 05:24 am »

Quote from: Mass. Wine Guy on 20 Dec 2010, 05:22 am

The amp arrived yesterday and I hooked it up with a Beresford 7520 DAC in the mix. I'm going to remove it to see how things sound without it. I need to do a lot more listening before I judge this amp completely. It images very well, good sound stage. I'm not positive that I like the overall sound as well as with my Adcom 535, but this is a very tentative observation.

I also have a hum since installing the amp. A cheater plug did not remove it.

Are you using it with XLR or RCA inputs? Are the jumpers installed accordingly?

Mass. Wine Guy · « **Reply #2303 on:** 20 Dec 2010, 05:41 am »

I'm using RCA connections. Jumpers?

TrungT · « **Reply #2304 on:** 20 Dec 2010, 05:44 am »

MWG
Shoot some picture.

jtwrace · « **Reply #2305 on:** 20 Dec 2010, 05:48 am »

Quote from: Mass. Wine Guy on 20 Dec 2010, 05:41 am

I'm using RCA connections. Jumpers?

Did the previous owner use RCA's? If so, then you should be all set. If not, you do need to install the jumpers for RCA operation.

jtwrace · « **Reply #2306 on:** 20 Dec 2010, 05:53 am »

From Class D:

The important thing to remember is… do not use the – on the input for single ended. Connect the + to + and the negative to G (ground). If you connect to -, it will damage the amp. For balanced input, just remove J1 and J2 jumpers completely. J1 and J2 have jumpers on pins 2 and 3… this is for single ended input. If you change the jumpers to pins 1 and 2, it will reverse the polarity… most situations this will probably not sound as good, so no need to mess with that.

For the potentiometers included, the black wire goes to the center pin on the pot, and if holding the pot with pins facing up, the yellow wire goes on the left, and the red wire on the right.

wushuliu · « **Reply #2307 on:** 20 Dec 2010, 07:03 am »

Quote from: Mass. Wine Guy on 14 Dec 2010, 01:36 pm

Uh, resistors? I thnk I remember what those are from my Vietnam War protest days.

Ha. That gave me a good laugh...

waltsok · « **Reply #2308 on:** 20 Dec 2010, 02:19 pm »

Wow, I didn't know about the input wiring importance. I must have gotten lucky and wired the negative to ground, properly. I received no instructions with the sds254, but did with cda224.

On quick note the Holcos provide a much smoother presentation, less grain, warmer with better image depth and resolution than with my PRP resistors, and surprisingly, easily discernible. I also have some Takmans and Rikens I'll report on if any different.

Nick77 · « **Reply #2309 on:** 20 Dec 2010, 02:56 pm »

Quote from: waltsok on 20 Dec 2010, 02:19 pm

Wow, I didn't know about the input wiring importance. I must have gotten lucky and wired the negative to ground, properly. I received no instructions with the sds254, but did with cda224.

On quick note the Holcos provide a much smoother presentation, less grain, warmer with better image depth and resolution than with my PRP resistors, and surprisingly, easily discernible. I also have some Takmans and Rikens I'll report on if any different.

Very curious to hear a report on the Rikens, one of my favorites. Thanks

Mass. Wine Guy · « **Reply #2310 on:** 20 Dec 2010, 03:20 pm »

Quote from: jtwrace on 20 Dec 2010, 05:53 am

From Class D:

The important thing to remember is…

I do not understand this at all. The unit was built by the seller, who did use RCA cables. All I did was connect everything to the proper right/left or positive/negative.

jtwrace · « **Reply #2311 on:** 20 Dec 2010, 03:23 pm »

Quote from: Mass. Wine Guy on 20 Dec 2010, 03:20 pm

I do not understand this at all. The unit was built by the seller, who did use RCA cables. All I did was connect everything to the proper right/left or positive/negative.

Fine. Then start the troubleshooting process as you normall would. Shut off each component one by one going to the amp. Does the hum go away?

Mass. Wine Guy · « **Reply #2312 on:** 20 Dec 2010, 07:59 pm »

Ok. I disconnected every thing except the preamp, amp and speakers. Hum still present. I've requested that the seller let me return the amp to him.

jtwrace · « **Reply #2313 on:** 20 Dec 2010, 09:23 pm »

Quote from: Mass. Wine Guy on 20 Dec 2010, 07:59 pm

Ok. I disconnected every thing except the preamp, amp and speakers. Hum still present. I've requested that the seller let me return the amp to him.

That's not what was recommmended above though. Shut off each component one at a time until you get to the amp, if it's still there then unplug the inputs and leave the amp on with the speakers connected.

This really isn't hard. We'll get it fixed with a little bit of patience. Worst case is that something took a shot in shipping. Everything is easily fixed though.

Mass. Wine Guy · « **Reply #2314 on:** 20 Dec 2010, 09:44 pm »

I will be glad to do the troubleshooting steps again and try getting it right. Thanks.

Badwater · « **Reply #2315 on:** 21 Dec 2010, 02:31 am »

I have read most of this very long thread and have pulled the trigger on two SDS 224 amplifiers, large power supply and gigantic transformer. Ordered last Thursday night and it arrived today. Great service.

I have read most of this very long thread, but still have couple of simple questions: On the SDS board is it necessary to install the LEDs and the on/off switch using the molex connectors or can I just leave them off for the time being? I know that the gain pots are required but not sure about the rest.

i plan to install this in old Dynaco SCA80Q integrated amp case that I have as a first cut to see how it goes. I should be able to use the speaker terminals, RCA's, on/off switch and power cord.

Thanks,

Bill

jtsnead · « **Reply #2316 on:** 21 Dec 2010, 03:31 am »

you do not have to install the leds and switch

Feanor · « **Reply #2317 on:** 21 Dec 2010, 03:33 am »

Quote from: Badwater on 21 Dec 2010, 02:31 am

I have read most of this very long thread and have pulled the trigger on two SDS 224 amplifiers, large power supply and gigantic transformer. Ordered last Thursday night and it arrived today. Great service.

I have read most of this very long thread, but still have couple of simple questions: On the SDS board is it necessary to install the LEDs and the on/off switch using the molex connectors or can I just leave them off for the time being? I know that the gain pots are required but not sure about the rest.

...

No, it isn't necessary to connect the LED or On/Off cables. Just leave them unconnect as I did when I first put the amp together. In my case, I eventually added the On/Off and pairs of blue LEDs for Power On and amber LEDs for Standby -- but this is entirely optional.

I guess using Standby voids "in rush" (or whatever it's called) when the AC to the power supply is switched on and leaves the power supply capacitors fully charged -- not that the seems to cause noice or any other problem with the SDS.

topp · « **Reply #2318 on:** 23 Dec 2010, 09:32 pm »

What are you guys using for your internal wires?
AC electrical runs?
Board to RCA input jacks?
Board to binding posts?

Thanks,
Topp

guest44244 · « **Reply #2319 on:** 25 Dec 2010, 04:26 am »

has anyone in the houston texas area built one of these ? would like to build a cda-1000 and 2000 but this looks like a little over my head and i have no soldering abilities .
donc

$175 Class D amp--120 wpc

guest44244