[mboxler]

So, would something like a pure I-20 work with one of these amps?
Or would you still need a separate pre-amp?

I think it should work...the problem would be with volume control.  The remote for my i-20 was crappy at best, and stopped working soon after I bought it.  If/When that happens, you'll either be manually adjusting the i-20 volume using your docked device, use BOTH gain controls on the SDS amp, or a combination of the two.

I'll try it tonight and report back.

Mike

[mikeeastman]

Nothing is grounded because it runs off D/C, as far as I know there is no gnd in D/C gear. If I'm wrong about that were would the GND run to? 

[mboxler]

Nothing is grounded because it runs off D/C, as far as I know there is no gnd in D/C gear. If I'm wrong about that were would the GND run to? 

I'm new to this, but here is how I understand it...

Circuit ground should equal the greatest negative potential in the circuit (in your case...-50 volts DC).  This way, everything in the circuit will measure a positive voltage from that point. 

A metal chassis can have varying effects on components contained within it.  By connecting the chassis to the amp, both the chassis and the amp will be at the same potential, reducing unwanted interferance.

I can't remember, but are the standoffs aluminum?  As I recall, the chassis ground on the board is also a mounting hole.  As long as there is no paint or anything to open the connection, you may have connectivity from the board to the chassis automatically.  A DMM will tell.  If not, do what Trung says.

Okay, let the corrections to my explanation begin 

Mike

[krikor]

Never got around to fusing my SDS monos, but figure I should now that they have become a permanent fixture and I can seal up the chassis.

Any reason, safety or sound quality, I wouldn't want to use these manual reset circuit breakers in lieu of fuses?

http://www.parts-express.com/pe/showdetl.cfm?partnumber=075-154

[vlad335]

Question: I am considering buying the SDS-1000 kit to run the front stage of my system. Would it be OK to run just 3 channels for L/C/R and leave one channel idle with the SDS 254 modules?

[underdawg]

yes resetables can fail shorted and never blow in my experience when a fuse goes its gone.

[mboxler]

Question: I am considering buying the SDS-1000 kit to run the front stage of my system. Would it be OK to run just 3 channels for L/C/R and leave one channel idle with the SDS 254 modules?

That would be okay.  However, if your center channel speaker is less efficient than your left/right, you may want to bridge one of the amps to drive the center, and drive the left/right with the other.  Is the center channel 8 ohm?  Tom's site doesn't show power into a 4 ohm speaker with a bridged SDS 254. 

Just a thought.

Mike

[vlad335]

That would be okay.  However, if your center channel speaker is less efficient than your left/right, you may want to bridge one of the amps to drive the center, and drive the left/right with the other.  Is the center channel 8 ohm?  Tom's site doesn't show power into a 4 ohm speaker with a bridged SDS 254. 

Just a thought.

Mike

All three speakers are 4 ohm with identical drivers, ( 3 way Swope center and towers.) so if I can run 3 channels that would work great. Maybe use the spare channel for another sub later.

Thanks

[krikor]

What's up with the classdaudio website? Just tried to look up some info and I get errors and different languages. Anyone else seeing this or is it just me/my browser?

[srb]

It's not you, it's the website.

[vlad335]

Looks like they changed the website again. Looks nice but pretty much the same info. No more USPS shipping and the Audio Circle code no longer works.

[bruson2]

I've been lowering the gain on my amps to match my subs better.
Going from 11K resistors to 14K the amps have gained in clarity at a moderate volume. I did not expect any change.
Same brand Vishay resistors.
Anybody else notice this effect?

Speakers: B&C DE 250 tweeter, B&C 10PS26 woofer.

[mboxler]

I've been lowering the gain on my amps to match my subs better.
Going from 11K resistors to 14K the amps have gained in clarity at a moderate volume. I did not expect any change.
Same brand Vishay resistors.
Anybody else notice this effect?

Speakers: B&C DE 250 tweeter, B&C 10PS26 woofer.

Hi...

Do these resistors replace the 10K pots?  I'm not sure how you are getting any volume at all.     Or do the newer amps have different pot values?

Mike

[maxitonus]

Some opinions from a french audiophile:
-I use my SDS470 with Duntech Prince's,i have just removed the RCA inputs which allows to  avoid a parasitic capacitance(better)
-The treble precision and balance are highly depending upon the pot's position, the best being around 50% opening (i'ts connected directly to my Weiss DAC2 which has a digital volume adjustment)
-In order to favourize extreme treble,i advise to use litz balanced XLR interconnects, the best for me is (+)8X0,28 (-)4X0,28+25X0.05 ground:1 or 2 AWG24 wrapping wire (silver plated)(dia 0,51),minimum length
The best  mains power cable is made with 4 wires, each one having 8X0,28 litz strands,2 are turning clockwise, 2 counterclockwise, in order to reduce inductance to the minimum possible.

The result as obtained when listening can be compared according to my personal opinion) to the best amps available today,( i own also an AYON TRITON II), but a friend allowed me to test also at home a DEVIALET D premier,and i think one couldnt recognize the 2 amps if blind tested.

[sl_1800]

I think it's time to move up. I have used a CDA-254 kit for 2 1/2 years, today I ordered the SDS-470 kit.  I would like to find a chassis for it that is different than the stock Class D chassis, I really don't like  IEC connectors, prefer PowerCon, and I prefer SpeakCon over binding post.

[bruson2]

Hi...

Do these resistors replace the 10K pots?  I'm not sure how you are getting any volume at all.     Or do the newer amps have different pot values?

Mike

I tried 18K for more clarity. The negative feedback sound was, uh, negative to my ears. I think increasing amounts of negative feedback is used to reduce the gain, to a point.
Tried 1k for fun. More gain, a lot more PS and amp noise. Less clarity.
Now using 4.7k and attenuating volume into amp with resistors to match sub level.

[john dozier]

I have the Spiral Groove Mastering amp and found the best sound was obtained by removing the gain fixing resistors. Regards

[mboxler]

I have the Spiral Groove Mastering amp and found the best sound was obtained by removing the gain fixing resistors. Regards

Hi

Is this the Spiral Groove Studio One mixing monitors Amplifier ($600)?   There isn't a lot of info regarding this amp, but the review (which could be yours) is stellar.

Mike

[john dozier]

The review is mine. The more I improve the front end of my system, the better the system sounds-real proof of a transparent amp. As you know, class d is not digital, but it is high frequency, needing special design and layout techniques as well as careful choice  of components. For example, ClassD audio uses Niobium coupling caps (the only use of them that I know of) This care in selection and layout, I think produces an amp that can compete with the best in the world. There is a great deal of high speed circuitry knowledge in California. Regards John Dozier

[bruson2]

I have the Spiral Groove Mastering amp and found the best sound was obtained by removing the gain fixing resistors. Regards

Does Spiral use the same input opamp, or transistor, as the SDS series?

I'd like to remove my gain R, but would removing it cause instabilities in single ended configuration (versus balanced)?

Did you replace the R with a wire or nothing?