[Steidl Guitars]

No life....

Bummer.  What speakers are you driving?  What pre-amp and source?  Just curious...

[wushuliu]

As it is its barely worth what I paid for it

Well, there are a lot of descriptions a lot positive some negative in this thread but I don't recall no life or involvement type of remarks. Certainly not the above statement, even by the disenchanted. Maybe you've already done this, but if you could give a run down on your setup as requested above that would help.

That said, could be you just don't care for it. If *everyone* said they loved these amps, I'd be worried.

EDIT: looking back your previous posts you mention dull sounding and 'upfront' as well and I do think there is some bad synergy. Something isn't right.

[pelliott321]

sorry I did not mean to come across that harshly and I did get a person flame from a member



I was hoping to use these amps in an 3 way active xover system.  This was going to be the mid panel amp, but when I listen to this amp compared with the TAD 60 tube amp (55watts per channel) or even the dbSystems 150watt monos I use for the bass panels (which is known for being dark sounding which is why I use for the bass), the Damp just sounds dead.  It improved with the doubling of the PS caps with a wondercap bypass.  Its is listenable and  if I did not have anything to compare it to I would say its fine, but its not
If any one has another suggestion for pumping some more air in this thing I will give it a try otherwise its a boat anchor and not a very good one at that   

[poseidonsvoice]

The version of the Class D amp you have (which isn't the SDS254-the upgraded balanced/differential version) would probably not have the bloom of a tube amplifier-sorry. You might want to try another TAD 60 for your midrange amplifier. The other option is the SDS254 which is what I have.

Maggies are nice speakers but they are very power hungry, active crossover or not. Active crossovers really do help though. Although they advertise sensitivities of 85dB/2.83V/1m, the ones I have seen actually measured are about 81-82dB/2.83V/1m. They drink wattage.

Where do you live? Do you have anybody nearby that can lend you the SDS 254?

Anand.

[Steidl Guitars]

if I did not have anything to compare it to I would say its fine, but its not

Surely you've tried other gear that you didn't like as well as what you already own -- heck, I sure have, and those usually cost me a lot more than what this unit costs. 

Clearly, this amp doesn't work for you in your rig, despite it working well for others.  Cut your losses and move on, life's too short. 

 

[toxteth ogrady]

Impedance matching is critical with these amps. What you're describing sounds like an impedance mismatch. Your photo doesn't show what your source or preamp is and that's the first place I would start looking. That said in my experience Class D in general does not convey 'emotion' the same way that tubes or even solid state can. Again, I state this as my experience, but it is simply one of the areas that I believe class d can't compete with tubes or good solid state. In other areas it can run circles around tubes and solid state.

[corndog71]

Can anyone tell me the dimensions of the SDS-258 and Heavy Duty DC Power Supply PCB's?

[poseidonsvoice]

Impedance matching is critical with these amps. What you're describing sounds like an impedance mismatch. Your photo doesn't show what your source or preamp is and that's the first place I would start looking. That said in my experience Class D in general does not convey 'emotion' the same way that tubes or even solid state can. Again, I state this as my experience, but it is simply one of the areas that I believe class d can't compete with tubes or good solid state. In other areas it can run circles around tubes and solid state.

That's a good point. The input impedance of the CDA-254 is a very low 3K (or maybe 7K if its one of the newer iterations-see website) which was a design oversight in my opinion. The input impedance of the SDS254 on the other hand is 47K! This can make a massive difference, if your preamp is not up to the task.

Anand.

[pelliott321]

output impedance on my preamp is less than 200ohms

[pelliott321]

Anand, i really do not understand you comments about active xovers. 
At least what I am thinking about is what sits between pre-amp and amp.  It would have three channels per side controlling the the lowpass, bandpass and high pass to the bass amp, mid amp and ribbon amp.  I am looking at two possibilities.  Building the linkwitz 4way on Paul Elliotts (esp) site or the easy way minidsp.   I might go with minidsp because its cheap and easy to see if this will ork and if so then build the analogue way 

[poseidonsvoice]

Anand, i really do not understand you comments about active xovers....

You don't have to. It's just my opinion (which isn't worth much to anybody but myself!). Expanding on it would go off topic, so if you would like to know, you can pm me, that's okay.

All the best in your search for audio nirvana,

Anand.

[LejfK]

Long time listener, first time caller:

I've been following this thread for a while b/c I've been thinking about adding external aps for the front two or three channels of my system. I run Strata Minis (and a Ref 100 center) off of a Pioneer SC-05.  It has pre outs.  I've always thought I could use some more headroom and last week I blew some internal fuses during a particularly raucous movie scene so now I really think I could really use more headroom.

I'm not too technical but I can follow instructions.  It looks like the SDS amps are preferred.  I've been thinking of making mono blocks because I've always dug the idea.  I'm also leaning towards those connectix switching power supplies that wishuliu tried for simplicity - although if linear really is the way to go, I could probably be talked into it.

So,is this plan reasonable/feasible, or am I missing something?  Would the pre-outs work on the SC-05?  How sensitive are these amps to connectors/internal wires?  Any other suggestions - I'm all ears.

[Rclark]

A few questions:

Would the sds 1000 kit, or dual 254's work as biamped monoblocks?

Would I need two cases for that?
referring to the new kit that has dual 254's, to be clear.
Is that one guy still building cases for these things?

[regis]

mmm hi
 i have this buffalo II and want to use the balanced output  section using the XLR output connectors to connect to a SDS-258 balanced XLR input .
      I have a SE preamp  only using the  + and GND , . it' of no use  if i want balanced output to the SDS-258 ! ?
 
     My guess is i need to find a balanced preamp with in/out XLR's . ,  to keep the stereo balance philosophy optimized ?

Output on this will be appreciated

regards
rolie.

[jtwrace]

Is that one guy still building cases for these things?

I don't think he is.

[regis]

HI Folks   
 i have this buffalo II and want to use the balanced output  section using the XLR output connectors to connect to a SDS-258 balanced XLR input .
      I have a SE preamp  that i want to add so i can use  use the volume pot on it  . By doing so ....will it annul my setup of the buffalo II and SDS-258 balanced topology ?
 
     

some feedback   will be appreciated

regards
rolie.

[stigs]

Hey Rclark.If you are looking for a reasonable case you might want to look at a Techical Pro PA1000 which I used for my build as it has all the hard work done for you.Rear panel has rca,1/4 inch and xlr for inputs,also for outputs it has speakon jacks as well as 5 way binding posts.For power it has a fused IEC jack.I removed the 1/4 inch input jacks for Cardas GRFA rca jacks and Cardas CCGR binding posts.One more feature this amp has that is note worthy is that it has gain control on the front panel which I modified to accept the SDS254 gain controls.Amp was purchased at Amazon real cheap,and all other jacks purchased at Sonic Craft on line.Front knobs I got aluminum ones at Rat Shack.

[runemaster]

Hi all,

I have read all the pages from first to here, and something caught my interest - Gain. Can anyone please explain to me :

1. does preamp's gain be a match to the Class D amp's gain? Saw an add on a preamp stating Gain = 12db. Then what should I set the gain for Class D amp if I am in this situation?
2. technically, why must the preamp's gain be the same as power amp?
3. If a buffer is used, which is no gain, must the power amp's gain be max out?
4. What is the difference or disadvantage if the gain of preamp does not match up with Class D amp?

Thanks for helping. I bought 2 SDS-224 and was hoping to make them into a monoblock. Still waiting for the amp since last week. Hope that I can get my hands on the the next week

cheers

[jtsnead]

I am using my mono sds-254 amps witha Dodd Audio Buffer with out any problems and it sounds great!

I would leave the gain pots all the way up or do as others have and install Vishay resistors for the pot's to full/fixed gain.

[dwk]

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.