$175 Class D amp--120 wpc

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avionic

Re: $175 Class D amp--120 wpc
« Reply #2440 on: 26 Mar 2011, 05:11 pm »
Shipping seems to take some time from connex. You can go to this link and ask Cristi directly     http://www.diyaudio.com/forums/connexelectronic/
 He seems to monitor that board fairly closely and should get back to you soon.

wushuliu

Re: $175 Class D amp--120 wpc
« Reply #2441 on: 26 Mar 2011, 05:16 pm »
For those that have bought an SMPS from connexelectronic, how was the experience?  I ask because I placed an order for a 500VA unit 2 weeks ago and it still shows as 'processing' on their site. Aside from the auto-responder when I placed the order, I've heard nothing from them despite sending them a contact email via the form on the site.

I did ask for a 32v version of the unit so it's possible that there is some work needed to process the order, but 2 weeks with no contact or feedback starts to get a bit concerning even for a smaller internet vendor.

Yes it's a bit frustrating buying from him (Cristi). My first experience was very irritating and I had to learn to go with the flow. It's a one-man part-time operation and he never tells you if he's out of town or backed up. Still, I've ordered multiple times and all items came through. If you ordered regular air mail and not express it will take about 3-4 weeks. Looks like he hasn't posted on diyaudio for about 2 weeks as well.

dwk

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Re: $175 Class D amp--120 wpc
« Reply #2442 on: 26 Mar 2011, 09:24 pm »
Thanks for the feedback. If this is somewhat typical, then I'm not going to freak out about it at this point.

corndog71

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Re: $175 Class D amp--120 wpc
« Reply #2443 on: 28 Mar 2011, 07:27 pm »
I want to build the 250x2@8ohms amp which calls for 60-70v transformer.

I see Antek has a 1000VA transformer that's rated 64v / 7.8A

So my question to anyone who can answer is what size fuse should I use?

8amp?

sts9fan

Re: $175 Class D amp--120 wpc
« Reply #2444 on: 28 Mar 2011, 07:32 pm »
If you want 60-70VAC that transformer is not correct.  That will give you closer to 90VAC with a standard bridge.

corndog71

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Re: $175 Class D amp--120 wpc
« Reply #2445 on: 28 Mar 2011, 08:02 pm »
 :o
Seriously?

...   :scratch:

Are you sure?

So would something like this be more suitable?
http://www.antekinc.com/details.php?p=132

srb

Re: $175 Class D amp--120 wpc
« Reply #2446 on: 28 Mar 2011, 08:11 pm »
If you want 60-70VAC that transformer is not correct.  That will give you closer to 90VAC with a standard bridge.

You meant to say "DC" in both cases?
 
The power supply requirements for the amplifier boards are in DC volts (i.e. +/- 60VDC to +/- 70VDC).  The transformer specifications are in AC volts.  After rectification the DC output will be 1.414 X the transformer secondary AC voltage.
 
60VAC input X 1.414 = ~ 85VDC
70VAC input X 1.414 = ~ 99VDC
 
Decide on your target DC voltage then either multiply that by .707 (or divide by 1.414) to determine the proper transformer secondary AC voltage.
 
Example:  65VDC X .707 = 46VAC transformer secondary voltage
 
Steve
 
 
 
 

corndog71

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Re: $175 Class D amp--120 wpc
« Reply #2447 on: 28 Mar 2011, 08:44 pm »

You meant to say "DC" in both cases?
 
The power supply requirements for the amplifier boards are in DC volts (i.e. +/- 60VDC to +/- 70VDC).  The transformer specifications are in AC volts.  After rectification the DC output will be 1.414 X the transformer secondary AC voltage.
 
60VAC input X 1.414 = ~ 85VDC
70VAC input X 1.414 = ~ 99VDC
 
Decide on your target DC voltage then either multiply that by .707 (or divide by 1.414) to determine the proper transformer secondary AC voltage.
 
Example:  65VDC X .707 = 46VAC transformer secondary voltage
 
Steve

Thanks, Steve.   I'm still learning.

So would this be suitable?  http://www.antekinc.com/details.php?p=139

srb

Re: $175 Class D amp--120 wpc
« Reply #2448 on: 28 Mar 2011, 09:24 pm »
So would this be suitable?  http://www.antekinc.com/details.php?p=139

Yes, the 45VAC secondaries would give you ~ 64VDC after rectification by the power supply.  I always like to operate components at less than the maximum permitted voltages (but I have also been known to underclock my computers!).
 
I don't know which modules you are using, so the 1000VA transformer could be a little overkill, but I like big transformers, and what's an extra 2 pounds, .3"D and $16 among friends? (vs. the 800VA model AN-8445).
 
Have fun with the build.  I know some prefer SMPS power supplies vs traditional linear supplies, but I have not built one of these and can't comment on the difference with the Class D Audio modules.
 
Steve

HiroPro

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Re: $175 Class D amp--120 wpc
« Reply #2449 on: 30 Mar 2011, 11:19 am »
You guys are not going o like this.......



I bought one of these, sent it back for gain change, upgraded the PS by more than doubling the capacity and did a bypass with high audio quality cap, burned in for over 200 hours and I still thinkg it sounds most lacking.  No life, no envolvement.  I keep visiting this thread hoping to read that someone has found the magic bullet to make this thing sound like what you guys are whistling.
As it is its barely worth what I paid for it

You want the SDS-254 unit that can handle lower ohm speakers. Really for your setup you need SDS-254 run bridged. I'd also consider the DPS-500-s SMPS from audio power. Only then will the IR PWM really perform on those Maggies!!!
« Last Edit: 31 Mar 2011, 01:43 am by HiroPro »

bruson

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Re: $175 Class D amp--120 wpc
« Reply #2450 on: 30 Mar 2011, 12:52 pm »
Yes, the 45VAC secondaries would give you ~ 64VDC after rectification by the power supply.  I always like to operate components at less than the maximum permitted voltages (but I have also been known to underclock my computers!).
 ........
 
Have fun with the build.  I know some prefer SMPS power supplies vs traditional linear supplies, but I have not built one of these and can't comment on the difference with the Class D Audio modules.
 
Steve

I have one SDS 258 and run it stereo using +-72vdc from a connex SMPS with classDaudio approval.

It runs HOT! I will eventually get a PS with 60-65vdc for longer life.
The SMPS generates less heat but more than I expected.

I soldered the inputs on to the circuit board for improved sound.
Biggest improvement was getting rid of the gain control and soldering in vishays I had used in other projects. Those pots suck.

Sounds clean and clear, better than the icepower 1000 I was using. Great value.

It'll end up on the back of a speaker bi amping it and I'll get another later for the other channel.


corndog71

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Re: $175 Class D amp--120 wpc
« Reply #2451 on: 30 Mar 2011, 04:53 pm »
I have one SDS 258 and run it stereo using +-72vdc from a connex SMPS with classDaudio approval.

It runs HOT! I will eventually get a PS with 60-65vdc for longer life.
The SMPS generates less heat but more than I expected.

I soldered the inputs on to the circuit board for improved sound.
Biggest improvement was getting rid of the gain control and soldering in vishays I had used in other projects. Those pots suck.

Sounds clean and clear, better than the icepower 1000 I was using. Great value.

It'll end up on the back of a speaker bi amping it and I'll get another later for the other channel.

What value resistors did you use?

bruson

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Re: $175 Class D amp--120 wpc
« Reply #2452 on: 30 Mar 2011, 07:31 pm »
What value resistors did you use?

I used 10K to match my subwoofer level.

Speakers are a Geddes Nathan clone that I've built.
10" B&C driver and B&C de250 tweeter on a 10" DDS waveguide.
Fairly efficient speakers. Around 94-95dB

HiroPro

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Re: $175 Class D amp--120 wpc
« Reply #2453 on: 31 Mar 2011, 02:04 am »
You want the SDS-254 unit that can handle lower ohm speakers. Really for your setup you need SDS-254 run bridged. I'd also consider the DPS-500-s SMPS from audio power. Only then will the IR PWM really perform on those Maggies!!!

pelliott321 !!!!

Those Maggies would sound amazing with this transport proposition using ClassDAudio.com


PC-->Halide Design SP/DIF USB BRIDGE-->Audio-gd NFB-10WM DAC-->ClassDAudio.com SDS-254 AMP bridged with dedicated Audio Power DPS-500-S SMPS per module.

Now then and only then could you really make judgement using your expensive Magnepans regarding the IR PWM performance. It really doesn't matter how much capacitance you add to the reserves when the amp module it's self can't drive the speakers properly. Also the input section of the non SDS units are known to cause impedance issues. To be fair please do contact Tom and swap that amp for the SDS-254 and do consider a decent SMPS.

SDS-254 2 x $235 + DPS-500-S 2 x $225 plus the chassis you already have...

It's gunna take a grand of class D investment to drive those maggies properly!!! They eat current for breakfast and so does your xover I bet!!! You've never heard 20.1 with GB ribbon etc/mods until you've driven it with HIGH CURRENT!!! With a lot of loudspeakers it wouldn't pay off spending extra money on the SDS series bridged and that SMPS but your speakers most certainly would gain from the investment!!!

beat

Re: $175 Class D amp--120 wpc
« Reply #2454 on: 1 Apr 2011, 06:15 am »
Just ordered one of the new ti-600 kits.. i needed more power to my woofers which dip down to 2 ohm....  Will post results soon.

peace. Beat

pelliott321

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Re: $175 Class D amp--120 wpc
« Reply #2455 on: 4 Apr 2011, 06:45 pm »
Thanks HiroPro
I hear you.  I only want to drive the bass panel which is 4ohms.  I have 150watt SS driving them now and a 55 watt KT88 driving the mids and ribbon. I am in the decision process of which active xover I am going to get/DIY and then try the Damp on the bass panel my 150watt SS on the mids and the kt88 amp on the ribbon.
When I listen to the 254 full range on another (standard box speaker) of the maggy is when I hear this amp lacking.  There is plenty of power, its just lifeless, non-envolving, compared to my other amps.  It will be fine running the bass panel

I also run a pair of subs that go from 40hz on down and I cut off the maggy bass panels just above that.  My room gives me a bass bump from 40 to 60hz
 

HiroPro

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Re: $175 Class D amp--120 wpc
« Reply #2456 on: 4 Apr 2011, 08:44 pm »
You don't have SDS-254 I believe. That unit in your pictures looks like CDA-224. The PSU you have looks to small to have enough current even for the 224. I'd get a bigger linear or SMPS. This is what's affecting the SQ IMHO.

pelliott321

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Re: $175 Class D amp--120 wpc
« Reply #2457 on: 5 Apr 2011, 08:08 pm »
sorry I miss spoke I have CDA-224, which is irrelevant.  It works fine for the bass panels.  I just could not tolerate it as a main amp on any speaker.

rajesh

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Re: $175 Class D amp--120 wpc
« Reply #2458 on: 12 Apr 2011, 09:17 am »
I had purchased the CDA 254 in March 2010. Lovely mids and crisp highs but it is very lean in the bass department. Moreover, it heats up where I've marked in the pic.


mikeeastman

Re: $175 Class D amp--120 wpc
« Reply #2459 on: 15 Apr 2011, 03:45 pm »
I've have a CDA-254 (built by Gary Dodd) that I got to run a sub, but as I have't built the sub yet I thought I'd try the amp on my OB 7s, WOW. So now I have a SDS-254 on its way and I would like to up grade both amps as much as I can and as I've gotten some good tips off this site so far , figured this would be the place to ask. I also have a Dodd tube buffer kit coming and want to put both on the same chassis. The amp/buffer will have 1 set of inputs and I will not use any of the pots or switches . My system is battery powered and I'm using the 12 volt power supplies from Class D, any suggestion on up grades for them would also be appreciated. If this works out I plan to build a second amp/tube buffer and bi amp either a set of GR Super Vs or some other OB speakers. As I'm new to this,  pics and diagrams would be very helpful. Thanks in advance for what I know will be some great advice.