$175 Class D amp--120 wpc

Nick77 · « **Reply #2340 on:** 4 Jan 2011, 11:35 am »

Quote from: toxteth ogrady on 4 Jan 2011, 01:43 am

Thanks Nick. Did Tom say 63v capacitors would work well specifically with the 258 or was he speaking about the 254? 10000uf 63v snap-ins with a 35mm diameter will be much easier to find.

The conversation did revolve around the 254, might want to double check on the larger amp.

toxteth ogrady · « **Reply #2341 on:** 6 Jan 2011, 08:29 pm »

Here's a more exotic option for the power supply. The boards are designed to take Jensen four-poles. Hubba hubba.

http://www.musicaldesign.com/MC_PS200.html

EDIT - I just got an email back from John Hillig saying that Class D Audio has actually sent them some customers. So this supply will work--very tempting

Also for anyone looking to add more capacitance to their 258's using the stock boards, I found a U.S. source for United Chemicon 80v 10000uf's for dirt cheap prices: http://www.futureelectronics.com/en/technologies/passives/capacitors/aluminum-electrolytic-capacitors/Pages/5585385-ESMH800VSN103MA50S.aspx

poseidonsvoice · « **Reply #2342 on:** 6 Jan 2011, 08:51 pm »

Quote from: toxteth ogrady on 6 Jan 2011, 08:29 pm

Here's a more exotic option for the power supply. The boards are designed to take Jensen four-poles. Hubba hubba.

http://www.musicaldesign.com/MC_PS200.html

EDIT - I just got an email back from John Hillig saying that Class D Audio has actually sent them some customers. So this supply will work--very tempting

Also for anyone looking to add more capacitance to their 258's using the stock boards, I found a U.S. source for United Chemicon 80v 10000uf's for dirt cheap prices: http://www.futureelectronics.com/en/technologies/passives/capacitors/aluminum-electrolytic-capacitors/Pages/5585385-ESMH800VSN103MA50S.aspx

You can also get the Universal power supply board from Peter Daniel of Audiosector. It is also drilled for 4 pole capacitors if that's what you fancy. The price per board I think is $10.

Here is a link.

Anand.

rjyap · « **Reply #2343 on:** 7 Jan 2011, 04:36 am »

Anyone know the actual specs for SDS-4? Is it 250w @ 8ohm and 500w @ 4 ohm? What's the input voltage requirement? I try to email Tom twice for past one week but didn't get an answer to above question. I email Christi from Connexelectronics and advice to go for separate SMPS for each board due to better channel separation. So now I had a flexibility to either get 2 x SDS-258 + 2 x CDA-258 or 2 x SDS-4 + 2 x CDA-258. I'm getting one SMPS800R for front channel, SMPS500R x 3 units for center channel, surround and back surround speaker.

HT cOz · « **Reply #2344 on:** 8 Jan 2011, 02:39 am »

Wow did you guys see this thing? It even has the IEC socket! http://connexelectronic.com/product_info.php/cPath/25_46/products_id/124?osCsid=1ikvno4j5l4a85akd57lpui0c5

Barry_NJ · « **Reply #2345 on:** 8 Jan 2011, 03:00 am »

Quote from: HT cOz on 8 Jan 2011, 02:39 am

Wow did you guys see this thing? It even has the IEC socket! http://connexelectronic.com/product_info.php/cPath/25_46/products_id/124?osCsid=1ikvno4j5l4a85akd57lpui0c5

Yes, about 2 pages back...

http://www.audiocircle.com/index.php?topic=76400.msg885116#msg885116

boudy · « **Reply #2346 on:** 11 Jan 2011, 12:06 am »

What fuses are y'all with 60,000uf capacitance using? I just blew an 8A slow-blow, undoubtedly due to the high inrush current caused by the large capacitance.

mjosef · « **Reply #2347 on:** 11 Jan 2011, 12:15 am »

The power supply I used had 10A fuses, after I had souped up the capacitance to 55K uF, I tried 8A fuses which promptly blew...so went back to 10A, and it was all good.
YMWV

dwk · « **Reply #2348 on:** 11 Jan 2011, 04:29 pm »

Okay, finally got my SDS-224 up and running over the weekend. I figured letting it sit around for ~6 months or whatever would allow it to age like fine wine.....

Impressions so far are very good even just using the gain pots - resistor mod coming as soon as I settle on my gain setting.

I'm headed towards a 3-way active setup though, so I need another amp module. (woofers will be taken care of by an existing amp). My chassis isn't big enough for 2 amp boards plus the PS board plus the xformer though. I have a 2nd matching chassis that I could make into a power supply unit, but I'm a bit concerned at having the PS board that far away from the amp units - the idea being that shorter leads from the PS to the amp boards will allow better power delivery. (Is this really a big concern in practice?)

What do people think of having the xformer and stock ClassD PS board in one chassis, and then a 2nd ps board w/ caps (maybe the musicaldesign jensen unit) in the main chassis next to the amp boards? This 2nd stage would just be fed the DC from the initial supply. Would this type of 2-stage PS setup be prone to oscillation or other problems? I guess the alternative would be to simply house the xformer in the 2nd chassis and run AC into the amp chassis, but it seems like a missed opportunity to have a separate box and still end up having the rectification happen in the main unit.

bigdirty · « **Reply #2349 on:** 11 Jan 2011, 04:40 pm »

Quote from: dwk on 11 Jan 2011, 04:29 pm

My chassis isn't big enough for 2 amp boards plus the PS board plus the xformer though. I

using transformer covers, i mounted them on the outside of the enclosure.

boudy · « **Reply #2350 on:** 11 Jan 2011, 06:56 pm »

After blowing through 10 bucks worth of fuses I figured out that TA had taped the wrong two transformer secondary leads together for the center tap, d'oh!

Hopefully someone can benefit from my woes...

Quote from: boudy on 11 Jan 2011, 12:06 am

What fuses are y'all with 60,000uf capacitance using? I just blew an 8A slow-blow, undoubtedly due to the high inrush current caused by the large capacitance.

RichG · « **Reply #2351 on:** 21 Jan 2011, 11:16 am »

Hi Guys,

Just came here to ask if anyone has had contact with Tom recently?

I've been trying to email him for the last couple of weeks concerning an issue with a board but have not had any response. This is somewhat surprising as I have always had very quick response in the past and have been very happy with the service he has given (I've now bought four different amps from him). Perhaps he is on holiday?

cheers,
Richard

poseidonsvoice · « **Reply #2352 on:** 21 Jan 2011, 12:38 pm »

Quote from: RichG on 21 Jan 2011, 11:16 am

Hi Guys,

Just came here to ask if anyone has had contact with Tom recently?

I've been trying to email him for the last couple of weeks concerning an issue with a board but have not had any response. This is somewhat surprising as I have always had very quick response in the past and have been very happy with the service he has given (I've now bought four different amps from him). Perhaps he is on holiday?

cheers,
Richard

What issue is it? Perhaps we can help.

Anand.

RichG · « **Reply #2353 on:** 21 Jan 2011, 01:17 pm »

Thanks for the offer Anand, but it relates to a board which was DOA that I returned to him a number of weeks ago.

RichG · « **Reply #2354 on:** 21 Jan 2011, 06:04 pm »

I've just heard back from Tom so panic over and issue gone!! Tom was indeed having a break with family and getting ready for what is likely to be a busy 2011.

zoula · « **Reply #2355 on:** 22 Jan 2011, 02:58 pm »

Hi,

I have just purchased a SDS-254 and it come with no literature...
It is not a big problem since it could not be simpler to put together. But i have a little question about the supply.

If I what to fuse the input is a 2A slow blow fuse is ok???

Thank you

RichG · « **Reply #2356 on:** 23 Jan 2011, 11:45 am »

Quote from: zoula on 22 Jan 2011, 02:58 pm

Hi,

I have just purchased a SDS-254 and it come with no literature...
It is not a big problem since it could not be simpler to put together. But i have a little question about the supply.

If I what to fuse the input is a 2A slow blow fuse is ok???

Thank you

If your on 220/240v supply then 2A is probably just about enough but may blow due to in-rush current at switch on due to the supply caps charging. Probably safer to go for 3A. If your on a 110 Volt supply then use 5 or 6 Amp fuse.

Remember to keep some spares. There's nothing worse than a fuse blowing when you switch on and not having one to hand!

cheers, Richard.

Barry_NJ · « **Reply #2357 on:** 23 Jan 2011, 03:25 pm »

Quote from: zoula on 22 Jan 2011, 02:58 pm

Hi,

I have just purchased a SDS-254 and it come with no literature...

Literature is available on-line here...

http://classdaudio.com/index.php/Manual/?___store=default

jtwrace · « **Reply #2358 on:** 23 Jan 2011, 03:29 pm »

Quote from: Barry_NJ on 23 Jan 2011, 03:25 pm

Literature is available on-line here...

http://classdaudio.com/index.php/Manual/?___store=default

and the #2357 posts of literature.

Mitch311 · « **Reply #2359 on:** 23 Jan 2011, 03:59 pm »

Quote from: jtwrace on 23 Jan 2011, 03:29 pm

and the #2357 posts of literature.

So, with this said, this is going to seem a tad lazy.....

I'm looking at a Small Gigaworks High Grade 24bit/192khz DAC http://cgi.ebay.co.uk/High-Grade-24bit-192khz-DAC-fully-assembled-kits-/120551270004?pt=LH_DefaultDomain_0&hash=item1c116a6674 seen there.

This is to run into a CDA-254 with gain adjusted to 35. There has been some thought over at diyaudio that I would possibly need a buffer built between these two. Would this be the case? From my limited understanding of this issue, the gigaworks DAC is 75ohms output impedance where as the amp likes 7-10k ohms impedance in? Am I going to notice a SQ problem because of this?

I'm looking at putting in a stepped attenuator or dual gang log pot (10k impedance as recommended by Tom) in just before the amp as a volume control. I also plan to have a analog input (prob RCA) these two inputs would run through a DPDT switch for input selection and then through the volume control then into the amp.

Most likely analog input will be an IPhone. SPDIF or coax input from both a computer and the TV through the DAC which will be by far the most common sources.

TL:DR -> Do I need a impedance buffer for this amp? Will I notice a SQ difference?

Thanks for all the help.

Mitch