SB3 mod (including DAC mod) question..

95bcwh · « **on:** 31 Jan 2006, 03:44 pm »

Hi,
Have anyone tried Vinnie's full SB3 mod (i.e. using the modified DAC too, run the analog out to preamp)?

How does that compare with using the SB3 mod digital out running into DACs such as Benchmark DAC1, Bel Canto DAC1/2, + all other more expensive DACs..??

I'm sending my SB3 to Vinnie but I still haven't decided whether to go for full mod.....

Appreciate you sharing your experience..
RV

JLM · « **Reply #1 on:** 31 Jan 2006, 09:17 pm »

RV,

I have the full mods shown on the RWA site, but have only run it via analog outputs. It's sound quality without break-in matched my stock Sony S7700/Ack dAck! v.2 combo for less money plus adds volume control, full arm chair convenience, and internet audio streaming. I really don't see the need for a pre-amp.

Boybees · « **Reply #2 on:** 31 Jan 2006, 11:28 pm »

JLM,

Have you compared modded SB3 analog out vs. modded SB3 digital out/Ack! Dack! 2.0?

That’s the very comparison I’m fixing to make, once I get interconnects matched and properly burned in.

The Dack! 2.0 (I have the ultra-rez option) is an outstanding output stage. It’s a high bar to set for Vinnie’s analog mods . . .

95bcwh · « **Reply #3 on:** 31 Jan 2006, 11:44 pm »

JLM,
Wow..that's impressive... so Vinnie wasn't boasting when he claimed on his website that we can throw away our external DAC!

I wonder what is the impedence of the analog output stage of the SB3? I have a amp with 50k input impedence.

Thanks
RV

F-100 · « **Reply #4 on:** 1 Feb 2006, 12:58 am »

Output impedance on the SB3 is 220 ohms according to this FAQ.
http://angerman.net/squeezeboxfaq/book.html#SB-HARDWARE-IMPEDANCE

Vinnie R. · « **Reply #5 on:** 1 Feb 2006, 03:07 pm »

Quote from: 95bcwh

JLM,
Wow..that's impressive... so Vinnie wasn't boasting when he claimed on his website that we can throw away our external DAC!

I wonder what is the impedence of the analog output stage of the SB3? I have a amp with 50k input impedence.

Thanks
RV

Hi 95bcwh,

After analog output mods, the output of the SB3's is fed directly to the RCA output jacks (via Auricaps). According to the data sheet for this dac, it can drive as low as a 5k load. The 50k input impedance of your amp will work fine here. Keep in mind that after the mod, the max output voltage of the SB3 is reduced to approx. 1Vrms. As long as the input sensitivity of your amp is 1Vrms or lower, you'll be able to drive it to full power w/o a preamp.

Regards,

Vinnie R. · « **Reply #6 on:** 1 Feb 2006, 03:11 pm »

Quote from: Boybees

The Dack! 2.0 (I have the ultra-rez option) is an outstanding output stage. It’s a high bar to set for Vinnie’s analog mods . . .. . .

Yes, it is indeed a high bar.

By converting the SB to battery power and using the internal dac and modded output stage (instead of transmitting over the S/PDIF interface), you can expect the modded SB to be competitive with the dAck. Which one is better really depends on your system synergy and listening tastes...

95bcwh · « **Reply #7 on:** 1 Feb 2006, 03:16 pm »

Hi Vinnie,
It's good to have you back! I thought on your website you mentioned that the output level was reduced from 6Vrms to 3Vrms?

1 Vrms is a bit low I must say..I have a Bryston 4B-SST and there're two input sensitivity levels as follow:

29dB - 1.8Vin = 300W @ 8 Ohms
23dB - 3.6Vin = 300W @ 8 Ohms

Hence I think 1Vrms is stretching a little bit. I probably do need an active preamp

Oh, by the way, Vinnie, did you ever compare your DAC mod with other external DACs (as I mentioned in the first thread?)

Thank you for your time.
RV

Vinnie R. · « **Reply #8 on:** 1 Feb 2006, 03:20 pm »

Quote from: 95bcwh

Hi Vinnie,
It's good to have you back! I thought on your website you mentioned that the output level was reduced from 6Vrms to 3Vrms?

1 Vrms is a bit low I must say..I have a Bryston 4B-SST and there're two input sensitivity levels as follow:

29dB - 1.8Vin = 300W @ 8 Ohms
23dB - 3.6Vin = 300W @ 8 Ohms

Hence I think 1Vrms is stretching a little bit. I probably do need an active preamp

Oh, by the way, Vinnie, did you ever compare your DAC mod with other external DACs (as I mentioned in the first thread?)

Thank you for your time.
RV

Hi RV,

Sorry for the confusion. My website referred to the Vpp output, not Vrms. I will change this to avoid confusion.

If those sensitivity ratings of your Bryston are in fact Vrms, you'll need an active preamp with voltage gain
Yes, I've compared the battery modded SB3 to the battery-powered Monica 2 dac and battery-powerd SN dackit. It holds its own quite well against them

JLM · « **Reply #9 on:** 1 Feb 2006, 03:45 pm »

Boybees,

The Ack dAck! v.2 (with high output and high resolution options) was sold before the RWA fully modded SB3 was fully broken in. And I've been changing/modding amps so I really can't say with great definition. But without full break-in the RWA SB3 was a roughly a close match to the Ack dAck!

95bcwh · « **Reply #10 on:** 1 Feb 2006, 04:30 pm »

How much is this Ack! Dack! with high resoulation?

mcgsxr · « **Reply #11 on:** 1 Feb 2006, 08:12 pm »

http://www.ack-industries.com/dAck!.html is what you are looking for.

FYI, I sold off a highly modded external DAC, after hearing a stock SB3... I do intend to get it modded, but even in the native state, it is a great piece, and like JLM, for me, I don't need a pre, I sold that too!

95bcwh · « **Reply #12 on:** 1 Feb 2006, 08:12 pm »

ok, I just spoken to Bryston, they said that the 1.8Vin is Vrms therefore if I choose to use the analog out from modded SB3 I will need an active linestage.

dc_guy · « **Reply #13 on:** 2 Feb 2006, 04:42 am »

I have compared the two, going back and forth from the modded digital out (to a battery-powered Ack! Dack 2) to the modded analogue out.

I prefer the modded digital out. A little more top end, a little more sparkle, a little more soundstage. The analogue out is a little smoother, quieter, and smaller.

Paul_Bui · « **Reply #14 on:** 2 Feb 2006, 06:47 am »

Quote from: dc_guy

I have compared the two, going back and forth from the modded digital out (to a battery-powered Ack! Dack 2) to the modded analogue out.

I prefer the modded digital out. A little more top end, a little more sparkle, a little more soundstage. The analogue out is a little smoother, quieter, and smaller.

While I am breaking in the AudioSector NOS DAC with the modded SB2 as transport, I tend to agree except that I am not sure which I prefer just yet.

JLM · « **Reply #15 on:** 2 Feb 2006, 10:04 am »

95,

1.1 V rms SB output and 1.8 V rms Bryston input doesn't mean that it won't work, just that you'll lose 2 - 3 dB of output without a pre-amp. Depending on room size, amp size, speaker efficiency, how loud you listen, etc. it may be enough. You can always try it without a pre-amp.

In my case (6 wpc Clari-T and 89 dB/w/m speakers) the low output from the SB made the overall output marginal.

Boybees · « **Reply #16 on:** 2 Feb 2006, 11:57 pm »

Quote from: dc_guy

I have compared the two, going back and forth from the modded digital out (to a battery-powered Ack! Dack 2) to the modded analogue out.

I prefer the modded digital out. A little more top end, a little more sparkle, a little more soundstage. The analogue out is a little smoother, quieter, and smaller.

Nice summary. I've started my comparisons, and I've noticed some of what you describe but not enough to form a preference yet.

dc_guy · « **Reply #17 on:** 3 Feb 2006, 01:12 am »

Thanks! I love the RMA battery mods -- the background is really wonderfully black. I knew the Ack! Dack 2.0 would be hard to beat -- I've got the teflon caps and it has been long fully broken in.

My one regret is that the neither the Ack! or the Squeezebox have balanced outs.

95bcwh · « **Reply #18 on:** 3 Feb 2006, 06:11 am »

JLM,
You're right. Probably I should just give it a try. I have spoken to Bryston and they told me that with 1Vrms, the 4B-SST can only output maximum 100W into 8 Ohm.

I don't listen to loud music, and I have a very small room 3m width 3m height and 4.5m length, My speakers are a pair of Veracity HT3, rated at 85dB sensitivity, 300W.

but I have no clue how loud is 100W

JLM · « **Reply #19 on:** 3 Feb 2006, 11:13 am »

95,

100 watts = 20 dB of gain

With your room size there will be virtually no loss of spls (sound pressure levels) from the stated efficiency rating of your speakers.

In this case then, max in room spl = gain + speaker efficiency = 105 dB

Now the question for you is how loud 105 dB is. Get a hold of a spl meter. It most useful to know just how loud you listen. I found out I was listening at much lower spls than I thought. For me, 85 dB is quite loud. An even easier approach would be to just turn down the volume three of the smallest differences you can hear (one 1 dB equals the smallest perceivable difference) for a 3 dB (or half the power) loss. BTW 3 dB also equals half the difference between half as loud and as loud.