Thank you Devil Boy...
I appreciate all the help! |
Good news is the input voltage sensitivity of the sim is 490mv, so it only needs about a half of a volt to play at full power. If you get the dac and integrated you are interested in, you should be in good shape.....as long as you don't change the dac, since it has such a low output impedance. |
Devilboy-
Here are the specs on the 700i
including the input sensitivity
Type Solid State
Configuration Dual-Mono / Balanced
Class of operation - Amplifier A/AB
Single Ended Inputs (RCA) 5 pairs
Balanced Inputs (XLR) 1 pair
Input Sensitivity 490mV - 6.0V RMS
Input Impedance 23,700 Ω
Monitor Loop 1
Preamplifier Output 1 pair @ 50 Ω (RCA)
Output Device Types - Amplifier Proprietary MOON BiPolars - 6 per channel
Output Binding Posts Gold-plated WBT
Output Power @ 8 Ω 175 Watts per channel
Output Power @ 4 Ω 350 Watts per channel
Output Impedance 0.02 Ω
Damping Factor > 400 |
Although I don't know the output voltage sensitivity of the dac, I think the main issue is the sim's input impedance. 23,700 is waaaaay low. Personally I would avoid it. YMMV. |
Well, first of all, the input impedance of the sim is a VERY low 23,700 ohms. Personally, I wouldn't buy it based on just that spec alone. Even if your dac has a low output impedance, it kind of paints you into a corner acoustically. Meaning, if you keep the sim, you limit your dac choices to ones the MUST have a low output impedance. Apperently the dac you mention has a low output impedance of 33 ohms either from balanced or single ended, which would be ok with the sim. I think there are better amps (ss or tube), that would have a higher input impedance. Also, I don't see a mention of the output voltage of the dac. What is the input voltage sensitivity of the sim integrated? |
Hi Devilboy-
I looked up the specs of the 700i and the DAC that I am interested in.
Integrated Amp Sim audio 700i 23,700 ohms Input impedance
Specs on Tube DAC-II-MK2 Accustic Arts are below
Digital inputs up to 192 kHz: 2 x S/P-DIF; unbalanced 75 Ω (COAX)
1 x TOSLINK; optical
Digital input up to 96 kHz: 1 x USB 2.0
Digital inputs up to 48 kHz: 1 x AES/EBU; balanced 110 Ω (XLR)
1 x S/P-DIF; unbalanced 75 Ω (COAX)
1 x S/P-DIF; unbalanced 75 Ω (BNC)
Digital outputs: 1 x S/P-DIF; unbalanced 75 Ω (COAX)
1 x AES/EBU; balanced 110 Ω (XLR)
Analog outputs: 1 x balanced 2 x 33 Ω (XLR)
1 x unbalanced 33 Ω (COAX)
Using your rule of thumb I should be OK. Correct? |
Unless the integrated has a passive preamp section, incoming voltage, 2V,3V, etc, shouldn't be a factor since the preamp section usually would be active. You should note, however, the input impedance of the integrated. Incoming and outgoing impedance is important for EVERY component, regardless if it's cdp to preamp, dac to preamp, or preamp to amp. The general rule of thumb is that the output impedance of a component should be ten times LESS than the input impedance of the component it's going into. For example: if the output impedance of a cd player or dac (whichever your system has), is 5,000 ohms, the input impedance of the integrated amp should be 50,000 ohms or greater. 5,000 ohms is very high but they do exist. The industry standard for an amp's input impedance is 47,000 ohms. |
Devilboy-
Would this apply to an integrated amp?
Plan was to go Media server->DAC->Integrated amp |
Passive preamps don't have a gain stage. The only voltage driving the amp will come from the cd player or dac above the preamp. Make sure the input voltage sensitivity of the amp is less than or equal to the output voltage of the cdp or dac or else the amp won't play at full power. Impedance matching is equally important. |
I have a Sim Audio 700i integrated amp.
No plans to change. What is the ideal setup for best SQ?
Thanks |
What is the difference between active and passive pre-amp? |
Audioengr: May I ask why you believe a transformer based preamp is better than a resistor based preamp? |
Active preamps all add noise, distortion and compression. The only good thing is they usually have stronger drive than a DAC. Just get the right DAC with strong drive and use a transformer linestage.
Once you have a low-jitter source, you will easily hear what an active preamp does to this source. Many times, the gains in tranparency and detail from low-jitter are lost if you use an active preamp. |
what is issue with active pre-amp? thanks |
Music servers are easy to use, at least some of them. The problem with these is generally sound quality. It can be improved significantly by adding a digital reclocker.
If you want the best possible SQ, this will not deliver it. The best SQ is currently from a select group of USB to digital converters. You will need a computer, like a Mac Mini and playback software like Amarra to make these sing. Then need feed a decent DAC, like a Wired for Sound DAC2 or Metrum Octave.
Use a transformer-based preamp like these http://www.audiocircle.com/index.php?topic=89744.0 and you will get a good result. Use an active preamp or receiver, and all of the great SQ will be buried.
Steve N.
Empirical Audio |
I think you are on the right track. If you have no CD's, building a system around hi resolution downloads makes sense as your primary source. Part of what you should consider is your taste in music. If your interest is primarily classical, be aware that there are an enormous number of classical SACD's available, and SACD is possible only by playback of the discs. Even with that consideration, with outstanding equipment, SACD sometimes offers only marginal improvment over red book CD. The high res stuff I would expect to be closer still.
I have ~ 1600 CD's, hundreds of SACD's and a an outstanding CD player, and I still plan on putting together a computer based system within the next few years. If you want to focus on digital sources, you have to think that a computer (or server) paired with a DAC is the future. Might just as well go that way from the start! |
