[Barry_NJ]

I thought of posting in the existing sticky-ed thread, but it pertains to the lower powered offerings and is already very large, so I thought a new thread was warranted.

I'm interested in a dynamic, high-powered (500+ watts/channel), amplifier for my system, and there are a few options available on their web site:

TI-600 Kit plus a second TI-600 amplifier module, for 600 watts/channel @ $390

CDA-1000 Kit , for 500 watts/channel @ $325

CDA-258 Kit plus a second CDA-258 amplifier module, for 1000 watts/channel @ $450

It's a bit confusing because some of the descriptions aren't clear...

Package deal includes 1 of our most powerful 500W X 2, or 100W X 1 Class D Power Amplifier modules, Large Power Supply, 500VA AnTek Toroidal Transformer, and transformer mounting kit. This is a great combination of components for a complete audiophile quality power amplifier. The power supply included in this kit is capable or running two amplifier modules. With the included components you can build a 1000W 8 Ohm stereo amplifier or 4 channel X 500W 4 Ohm or 4 X 250W 8 Ohm.

Another confusing note...

Specifications:
· Output: 250 X 2 - 8 Ohm, 250 X 2 - 8 Ohm
· Bridged Output: Not Recommended

Will it do 1000 watts bridged as suggested in the CDA-258 Kit?

Looking at the differences between the CDA series and SDS series boards:

Our new Super D Series audio power amplifiers are built on the highly acclaimed reputation of our CDA series amps. Our goal was to keep the excellent sonic qualities while adding a state-of -the art balanced input stage (also accepts standard single ended input) and external adjustable gain controls. We've also added a better cooling system, Molex connectors for external LED's, power switch, and gain controls (included). The balanced input stage is one of the finest available and normally only found on very expensive high-end equipment.

I wonder if it's worth the cost difference for me(?) I don't plan on running a balanced input, nor do I feel the need for adjustable gain, as my pre-amp, an Audio Alchemy DLC, doesn't offer balanced output, and runs passive until 0dB and then goes into an active mode. I also have a Musical Fidelity X10-D line buffer that I thought I'd hard-wire, build into, the amplifier as an input buffer, so the lower input impedance of the CDA boards shouldn't be a concern.

Any thoughts or guidance is greatly appreciated.

Maybe Tom has time to chime in(?)

Regards, Barry

[srb]

When I inquired about the CDA-258 module back in late February, I was told that it could be bridged for use with an 8 ohm load, but not for a 4 ohm load.  I was also told that a larger upgraded heatsink was now standard on this module, though the website even now doesn't show it.
 
From Tom on 2/26/10:
 
"Yes, the [upgraded] heatsink for the 250W X 2 into 8 ohm is standard now.

Some like the idea of monoblocks, but you probably won't notice any sonic difference. These amps are very efficient and the power supplies are capable of running two amps with no problem. These amps when in mono mode are running in full-bridge mode. The sonic quality is the same in either stereo (half bridge) or full bridge mode. Only the 250W X 2 into 8 ohms is not recommended for 4 ohm in full bridge mode. Our other amps will run 4 ohm with no problem, either stereo or bridge."
 
I also asked about the TI 600 module and was told:
 
"The 600W amp is the TI chip and sonic quality is not as good as our other amps with the IR chip. Our IR based amps are some of the finest sounding audio amplifiers on the market today. The TI rating of 600W is actually at 10% distortion, so our 250W X 2 4 ohm, 500W X 1 8 ohm is actually rated full power at 1% so actually are more powerful. Our IR based amps are more powerful than people think and all are surprised when they listen to them. The actual distortion levels of these amps through almost all of the power range is more like .006%.... very good!"
 
Hope this helps shed a little light on the puzzle.
 
Steve

[Barry_NJ]

Thanks Steve, the information is appreciated. As my speakers are rated at 8 Ohms, I should be safe running the CDA-258 in Full Bridged Mono for a kilowatt of power to each channel.

[dvenardos]

Barry,
Just curious why do you need so much power?

Don

[Barry_NJ]

My current speakers, Anthony Gallo Acoustics 'Nucleus Reference 3.5', are less power hungry than my earlier 'Reference 3.1' version was, but they can easily handle the power, and really seem to come to life when the extra head room is available, even when played at lower volumes.

[dvenardos]

Fair enough.

[Barry_NJ]

Figured I'd post this here as it really helped answer some of my questions, but the running of the 258 boards in bridged mode is still in question...

I created a small table of the different boards with the official printed specs.  I can also work up an unofficial spec sheet if people will PM details of conversations with Tom regarding unpublished performance.



Kind Regards,
Robert

[Construct]

Figured I'd post this here as it really helped answer some of my questions, but the running of the 258 boards in bridged mode is still in question...

They have a commercial amp they call the SD4.  It is one ohm stable, but I don't have specs (Possibly 250 wpc in to 8 ohms)  Same price as the SDS-258.

[walkern]

I can't speak to the question of bridged operation, but I do have experience with the older and newer 254 model boards.  The overall character of the amps sound very similar to me, but with the SDS board (using exactly the same power supply) I'm getting a little more 3 dimensional soundstage, a little better layering of front to back depth, and perhaps a wee bit more refined sounding treble.  I'm not using balanced inputs, nor did I need the input level controls (using a Pass B1 buffer as a preamp)... so I would guess the subtle differences have only to do with the quality of the input section.  I've always admired the Gallo speakers for their terrific dimensional character, so the SDS boards might maximize their extraordinary talents in that arena.

In either case though, I think you'll be very impressed with how good the ClassD amps are.  Every time I fire up my system I am pleasantly surprised with how great my music sounds now.

Neil

[Barry_NJ]

Thanks Neil, very valuable information regarding the audible differences you found between the CDA and SDS boards.

[jtsnead]

Hi Barry,
I also have the SDS 254 which has killer soundstage and imaging,
I can relate to your situation I used to have Gallo 3.1's that I traded
in on my Joseph Audios, I felt I needed more midrange body, do you
get that with the 3.5's. I did have some Wyred4Sound monos (250w) driving
the 3.1's and it helped them open up and tightend up the bass a bit,
I did not have the sub amp.

So I would get the SDS-258, which I might be ordering soon also.
Good luck and let us know what you get.

JT

[Barry_NJ]

Hi JT, at the moment I'm still researching, but if I did get the 254 boards I'd get 2 and be running them bridged. The 3.5s are an 8 Ohm load not ht 4 Ohm of the 3.1, and yes, they do have more mid range body than the 3.1 did. They also have more immediacy and coherence than the 3.1 did. I really do love them.

[Barry_NJ]

Has anyone compared the TI and CDA/SDS boards? I seem to recall reading some where that the TI doesn't sound as good. If that's the case, why even sell them? The pricing/power is close enough that I'm not sure why one would purchase the TI board over the others.

[srb]

I seem to recall reading some where that the TI doesn't sound as good. If that's the case, why even sell them? The pricing/power is close enough that I'm not sure why one would purchase the TI board over the others.

It was Tom from Class D Audio that said that the TI's sonic quality was not quite as good as the IR based amps, and that the 600W amp's distortion was 10% THD at the 600W rating.
 
However, they are stable at 2 ohms and the IR-based amps are not, which would make them a better choice for very low impedance speakers or 2 ohm subwoofer loads.
 
Steve

[Barry_NJ]

Thanks Steve, that cleared things up for me.