or Connect
AVS › AVS Forum › Blu-ray & HD DVD › Blu-ray Players › Oppo BDP-105 "Sound Quality" Check Thread for Audiophiles
New Posts  All Forums:Forum Nav:

Oppo BDP-105 "Sound Quality" Check Thread for Audiophiles - Page 18

post #511 of 1458
Do you have a link to the -20db attenuators that you use?
Interesting hearing about people using amps with different ranges of input impedance with good success.
I had forgotten that Oppo had mentioned using something like that if impedance was too high or low on amp.
post #512 of 1458
SilverLitz,

So in your opinion, if starting a system from scratch and utilizing oppo as a preamp, you believe that a stereo amp with input impedance of 100k ohms would be preferable?
post #513 of 1458
Quote:
Originally Posted by SilverLitz View Post


I do not think an amp's input impedance would have much to do with the volume. The volume would be determined by the gain of the power amp.

Lower source (Oppo) output impedance and higher amp input impedance are generally a good thing leading to a flatter frequency response and particularly better bass. An amp with low input impedance is easier to drive, requiring less current from the source.

You are correct.  That tech(!) needs a lesson in Ohm's Law.

post #514 of 1458
Hi

Can anyone confirm that regardless of the setting I select for multi channel speaker configuration, that the dedicated stereo output (rca or XLR) will unaffected? If the stereo sound can be affected by these settings, how do I eliminate the interaction.

I'm a new user and a little confused by the myriad of settings. At the moment I am using the Oppo in a two channel stereo and am using the dedicated stereo jacks only.

Thanks
Barry
post #515 of 1458
Quote:
Originally Posted by Kal Rubinson View Post

You are correct.  That tech(!) needs a lesson in Ohm's Law.

Kal,

Thanks for weighing in on this issue...Do you believe I am going about my selection process for an amp the wrong way?

I would greatly appreciate an opinion from you regarding my search for an amp/amps that will mesh nicely with a 3.1 setup.

Speakers are 86db, 8 ohms nominal with dips to 6 ohms. Recommended wattage is 25-150
Room size is medium, price point is flexible to 5 grand.
Open minded about tubes for home theater.
Obviously to be run direct into oppo 105

Thank you for your input!
post #516 of 1458
Quote:
Originally Posted by Slinkee View Post


Kal,

Thanks for weighing in on this issue...Do you believe I am going about my selection process for an amp the wrong way?

I would greatly appreciate an opinion from you regarding my search for an amp/amps that will mesh nicely with a 3.1 setup.

Speakers are 86db, 8 ohms nominal with dips to 6 ohms. Recommended wattage is 25-150
Room size is medium, price point is flexible to 5 grand.
Open minded about tubes for home theater.
Obviously to be run direct into oppo 105

Thank you for your input!

With an output impedance of 100-200ohms, any amp with an input impedance from 10Kohms and up will work fiine.  Beyond that, there are too many options.  Currently, I am using a Parasound Halo A31 which might do but I have no experience with your speakers and these might be too much for them.  I have not used any tube amps in more than a decade.  

post #517 of 1458
Quote:
Originally Posted by Kal Rubinson View PostWith an output impedance of 100-200ohms, any amp with an input impedance from 10Kohms and up will work fiine.  Beyond that, there are too many options.  Currently, I am using a Parasound Halo A31 which might do but I have no experience with your speakers and these might be too much for them.  I have not used any tube amps in more than a decade.  

I though you were using Classe!

 

Have used the Oppo straight to the amps and if so what did you think better, same or worst that with a pre-amp?

post #518 of 1458
Quote:
Originally Posted by Kal Rubinson View Post

With an output impedance of 100-200ohms, any amp with an input impedance from 10Kohms and up will work fiine.  Beyond that, there are too many options.  Currently, I am using a Parasound Halo A31 which might do but I have no experience with your speakers and these might be too much for them.  I have not used any tube amps in more than a decade.  

Kal,

Thank you for clearing up that misinformation. I wanted to share with you the handful of options I have been going back and forth between. Under the misguided notion that I had to strictly adhere to a 470 to 1 ratio for the oppo to work properly, this makes life much easier in choosing an amp to pair with the oppo.

The speakers that I am trying to mate the amp to are 3 Gradient 5.0 bookshelf speakers. The .1 is a PSA XS-15 powered sub.
The following are what I'm trying to decide between:

1) Parasound Halo A31
2) Odyssey Stratos HT-3
3) Van Alstine Synergy 240/3
4) Bryston 9BSST2 3-channel amp
5) Vincent Audio SP-331MK and a Wyred 4 Sound mAMP

Anyone can chime in on this, but I would really appreciate your input Kal!
post #519 of 1458
Since I have no experience with your speakers, I cannot help except to point out that the Bryston 9B is a 5-channel amp. I have one of those, too.
post #520 of 1458
Quote:
Originally Posted by Slinkee View Post

Kal,

Thank you for clearing up that misinformation. I wanted to share with you the handful of options I have been going back and forth between. Under the misguided notion that I had to strictly adhere to a 470 to 1 ratio for the oppo to work properly, this makes life much easier in choosing an amp to pair with the oppo.

The speakers that I am trying to mate the amp to are 3 Gradient 5.0 bookshelf speakers. The .1 is a PSA XS-15 powered sub.
The following are what I'm trying to decide between:

1) Parasound Halo A31
2) Odyssey Stratos HT-3
3) Van Alstine Synergy 240/3
4) Bryston 9BSST2 3-channel amp
5) Vincent Audio SP-331MK and a Wyred 4 Sound mAMP

Anyone can chime in on this, but I would really appreciate your input Kal!
All good choices. I, like Kal have the Halo A-31. It's a good, solid performer and I think it's 250wpc into 8 ohms would work well with your set-up. Everything I've read regarding amplifier to speaker power ratios seemed to point to an amplifier whose rated power falls somewhere between 150 to 200 percent of a speakers rating is ideal. Far more drivers are damaged or destroyed by pushing an underpowered amp into clipping.
post #521 of 1458
Actually, the Bryston 9BSST2 can be ordered in a 3, 4 or 5 channel configuration.
post #522 of 1458
Torq,
Thanks for the power ratio numbers. I haven't heard that little nugget of info before.
post #523 of 1458
Quote:
Originally Posted by Slinkee View Post

Actually, the Bryston 9BSST2 can be ordered in a 3, 4 or 5 channel configuration.
ah, yes. I recall reading that a long time ago but I have never seen one with fewer than 5 amps.
post #524 of 1458
Quote:
Originally Posted by Slinkee View Post

Torq,
Thanks for the power ratio numbers. I haven't heard that little nugget of info before.
You can read your heart out HERE. It's the whole google search page and contains lots of articles on the subject.
post #525 of 1458
So I `ve been reading the Oppo manual, specifically DRC (Dynamic Range Compression). I think default setting is auto or on, but for pure audio I would think off would be your best bet. What is everyone doing with this setting?
post #526 of 1458
Quote:
Originally Posted by Slinkee View Post

Do you have a link to the -20db attenuators that you use?
Interesting hearing about people using amps with different ranges of input impedance with good success.
I had forgotten that Oppo had mentioned using something like that if impedance was too high or low on amp.
I am using attenuators from http://www.goldenjacks.com/
Ian Lamb can build you RCA or XLR ( not on a website, but he can custom built it for you)
Price was about 35GBP for the pair of -20db XLR attenuators.
Some reviews are here:
http://theartofsound.net/forum/showthread.php?t=8402
post #527 of 1458
Quote:
Originally Posted by Kal Rubinson View Post

ah, yes. I recall reading that a long time ago but I have never seen one with fewer than 5 amps.
It's available as a 3, 4, or 5 channel amp at Audio Advisor.
post #528 of 1458
I just added a set of large AQ Sorbothane feet under the unit. This had a very beneficial effect, making the sound more relaxed, and the sonic background apparently blacker.
post #529 of 1458
Quote:
Originally Posted by eganz1 View Post

I just added a set of large AQ Sorbothane feet under the unit. This had a very beneficial effect, making the sound more relaxed, and the sonic background apparently blacker.
I am assuming only CD, DVD and SACD playback could potentially be affected, but no digital sources like USB, HDMI or SMB/DNLA. Am I correct?
post #530 of 1458
Quote:
Originally Posted by RouslanB View Post

I am assuming only CD, DVD and SACD playback could potentially be affected, but no digital sources like USB, HDMI or SMB/DNLA. Am I correct?

Interesting I bought some on Amazon was going to try the same thing see if I can see a difference, I doubt it
post #531 of 1458
Quote:
Originally Posted by RouslanB View Post

I am assuming only CD, DVD and SACD playback could potentially be affected, but no digital sources like USB, HDMI or SMB/DNLA. Am I correct?
Yes, I observed this on SACD playback
post #532 of 1458

I acknowledged that it is available but I have yet to see one.

post #533 of 1458
Quote:
Originally Posted by wse View Post

Interesting I bought some on Amazon was going to try the same thing see if I can see a difference, I doubt it
If you guys are buying sorbothane check out McMaster-Carr.
I don't know what retailers are selling this stuff for now but in days past things like sorbothane feet were an uber-rip-off,imo.
You can buy sheets of it in different densities or least I did some years ago.
post #534 of 1458
Quote:
Originally Posted by Milt99 View Post

If you guys are buying sorbothane check out McMaster-Carr. I don't know what retailers are selling this stuff for now but in days past things like sorbothane feet were an uber-rip-off,imo. You can buy sheets of it in different densities or least I did some years ago.

Thank you, they still sell it what thickness should one use?

McMaster-Carr: http://www.mcmaster.com/#ultra-soft-polyurethane/=m7m3ip
post #535 of 1458
Quote:
Originally Posted by Slinkee View Post

SilverLitz,

So in your opinion, if starting a system from scratch and utilizing oppo as a preamp, you believe that a stereo amp with input impedance of 100k ohms would be preferable?

As I said before:
Lower source (Oppo) output impedance and higher amp input impedance are generally a good thing leading to a flatter frequency response and particularly better bass. An amp with low input impedance is easier to drive, requiring less current from the source.

I believe the important factor is the ratio of the amp's input impedance to the source's output impedance, and a good rule of thumb is for this to be a MINIMUM of 10-20X. Since the Oppo's output impedance is ~100, and amp with 100K ohm input impedance, and the 1000X ratio, should work together fine.
post #536 of 1458
Quote:
Originally Posted by Slinkee View Post

Bigguyca,
What volume do you listen to on the oppo? I spoke with oppo tech support trying to figure out the best amp to run direct into the 105. They give the recommendation that the stereo amp have an input impedance of 47k ohms. If a stereo amp with an input impedance of 100k ohms is used, it could be too quiet even at 100 volume level on oppo. In the opposite direction, an input impedance of 22k or below might make the volume level too loud even at lower volume levels on the oppo.

Further info on output impedance of oppo 105: Front L/R (both dedicated and multichannel) are both 100 ohms, but remainder of multichannel (C,surrounds, etc.) are 200 ohms.

They said that for optimum use of direct connections, 2 or more amps would be needed. A stereo unit utilizing 47k ohms and a second unit utilizing 100k ohms for center and surrounds.

Thought this might be helpful!

 

Slinkee ...

 

There's no law of nature in this universe(or others) that says the volume level of an amplifier depends on its input impedance!!! None whatsoever!

 

So you either misheard/misunderstood what he meant or he has no business being in the electronics business. As others have said, the volume of an amplifier is determined by two main things. Its input sensitivity and its gain. That's it and nothing else...

 

Now, on the question of valid input impedances, since the Oppo is a voltage source device with a low output impedance of 100-200 ohms, it will feed well into an amplifier with an input impedance is 100x or more, so 10K or greater. Most amplifiers fit this requirement quite easily as you may know.( BTW, basically the RCA output section of the 105 is an LM4562 with a 200 ohm output series resistor. The XLR has two 200 ohms in parallel for both legs to produce a 100 ohm equivalent resistance).

 

Now there are some amps which may have what I call 'exotic' input drive sections that are very reactive, i.e their input impedance varies widely with input frequency. For example, tt could be 10Kohm at 20Hz but 2Kohm at 20KHz. This can create problems to the source device as it constantly sees a fluctuating impedance instead of a constant one and hence change the combined frequency response (and possibly add distortion) of the whole setup... BUT I believe these amps are rare but in case they are not, then it would explain why some folks felt the direction connection of the Oppo outputs to their amps was a bad combination.

 

In summary, any modern amp should connect to the oppo just fine. If the input sensitivity of the amp is too low(e.g 100mV at the input to produce full scale output power), you can place HQ attenuators between the Oppo and the amplifier and will be right as rainsmile.gif... 


Edited by dmusoke - 4/7/13 at 10:30am
post #537 of 1458
Quote:
Originally Posted by turk 182 View Post

So I `ve been reading the Oppo manual, specifically DRC (Dynamic Range Compression). I think default setting is auto or on, but for pure audio I would think off would be your best bet. What is everyone doing with this setting?

Off,Off,Off ...did I say off?biggrin.gif Why would you want to compress your HQ lossless audio? If its to keep baby quiet or neighbors happy, then turn the volume down or watch in your own sound-proofed HT room.

post #538 of 1458
Quote:
Originally Posted by SilverLitz View Post

Quote:
Originally Posted by Slinkee View Post

SilverLitz,

So in your opinion, if starting a system from scratch and utilizing oppo as a preamp, you believe that a stereo amp with input impedance of 100k ohms would be preferable?

As I said before:
Lower source (Oppo) output impedance and higher amp input impedance are generally a good thing leading to a flatter frequency response and particularly better bass. An amp with low input impedance is easier to drive, requiring less current from the source.

I believe the important factor is the ratio of the amp's input impedance to the source's output impedance, and a good rule of thumb is for this to be a MINIMUM of 10-20X. Since the Oppo's output impedance is ~100, and amp with 100K ohm input impedance, and the 1000X ratio, should work together fine.

???... you meant to say an amp with HIGH input impedance is easier to drive, requiring less current from source....

post #539 of 1458
Thank you all for the great input and information!
post #540 of 1458
Quote:
Originally Posted by dmusoke View Post

???... you meant to say an amp with HIGH input impedance is easier to drive, requiring less current from source....

SORRY! Low output impedance good, high input impedance good. HIGH input impedance requires lower current. V = I *R; I = V/R, => as volume is driven by the voltage the amp's input sees, the higher the impedance (similar to R, but more complex, accounting for capacitance and inductance reactance as well as resistance), the lower the current needed.
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Blu-ray Players
AVS › AVS Forum › Blu-ray & HD DVD › Blu-ray Players › Oppo BDP-105 "Sound Quality" Check Thread for Audiophiles