A Guide to Amplifiers

[LP Scream]

Originally Posted by Big Daddy

The thread is too advanced for me too. I must have been intoxicated when I wrote it. Read post #2 of the Amplifier Manufacturers thread. It is much easier to understand.

http://forum.blu-ray.com/1457088-post2.html

Under normal circumstances, you are only using a few watts for an average movie. However, it is a good idea to have as much headroom as possible for the peaks. My recommendation is to buy the best and most powerful amplifier you can afford. The amplifier will have enough power to satisfy your needs and at the same time you will not have the urge to upgrade in the future.

According to JBL Pro:



http://www.jblpro.com/pages/general_faq.htm
http://www.jblpro.com/pub/technote/lowpower.pdf

If you plan to buy an external amplifier to power your speakers, don't waste too much money on a receiver. Just buy one that has pre-outs for all the channels and spend the rest of the money on a 3-channel or 5-channel Emotiva amplifier. If you don't plan to buy an amplifier, then buy the Onkyo TX-NR3008.

Thanks a lot Big Daddy!

I think I'll get the Onkyo TX-NR3008 .. but do you think getting the XPA-3 for the front and XPA-2 would make a real difference? especially with my Paradigm setup? would the front benefit from the Emotiva?

[crazyBLUE]

Originally Posted by LP Scream

Thanks a lot Big Daddy!

I think I'll get the Onkyo TX-NR3008 .. but do you think getting the XPA-3 for the front and XPA-2 would make a real difference? especially with my Paradigm setup? would the front benefit from the Emotiva?

The sound quality from running external amplification will be better then not having the amps LP.

I would just buy the XPA-5 instead of the XPA-3 & XPA-2 . That would be more then enough to drive the 5 speakers.

[Big Daddy]

Originally Posted by LP Scream

Thanks a lot Big Daddy!

I think I'll get the Onkyo TX-NR3008 .. but do you think getting the XPA-3 for the front and XPA-2 would make a real difference? especially with my Paradigm setup? would the front benefit from the Emotiva?

An external amplifier enhances the sound and gives you more headroom. However, don't expect a miracle, particularly if you are using a high quality receiver. After a certain point, you can spend one thousand dollars more and only receive marginal benefit. The benefits that you receive generally depend on your room & its treatment, your hearing, your equipment, particularly the speakers.

[rarredoa]

I have been asking questions similar to this for a while now, so I apologize. I found a schematic for a speaker-level to line-level converter. It is nothing more than a voltage divider circuit that attenuates the signal 47 to 1 using nothing more than a couple of quarter-watt resistors.

Any thoughts on this?

Will this generate any ground noise?

[Big Daddy]

Originally Posted by rarredoa

I have been asking questions similar to this for a while now, so I apologize. I found a schematic for a speaker-level to line-level converter. It is nothing more than a voltage divider circuit that attenuates the signal 47 to 1 using nothing more than a couple of quarter-watt resistors.

Any thoughts on this?

Will this generate any ground noise?

I have never used one of these, but I know that unbalanced (RCA) inputs/outputs of audio equipments are very sensitive to noise and hum, especially when you connect something else to them. Usually at short distances there should be no problems in using the adapter.

The High-to-Low Adapter can be made cheaply, but if you want to use it in home theater, make sure it has sufficient power rating. There are some inexpensive and some high-end options available that you can purchase from Amazon or Ebay. Some of them have additional noise blocking circuits. If you get any kind of noise problems, use an isolation transformer. Read the http://forum.blu-ray.com/home-theate...isolators.html.

[rarredoa]

Originally Posted by Big Daddy

I have never used one of these, but I know that unbalanced (RCA) inputs/outputs of audio equipments are very sensitive to noise and hum, especially when you connect something else to them. Usually at short distances there should be no problems in using the adapter.

The High-to-Low Adapter can be made cheaply, but if you want to use it in home theater, make sure it has sufficient power rating. There are some inexpensive and some high-end options available that you can purchase from Amazon or Ebay. Some of them have additional noise blocking circuits. If you get any kind of noise problems, use an isolation transformer. Read the http://forum.blu-ray.com/home-theate...isolators.html.

Sweet! Just the kind of answer I was looking for. Once I finish building the adapter (just waiting on rca jacks and banana connectors) I will use my RMS meter and see what kind of voltages I get out of the newly formed pre-outs. I was thinking of using pink noise. What do you think? What voltages should I expect?

According to the schematic I am using, the 47k ohm to 1kohm attenuation (1/4 watt resistors) should be sufficient to be used with an amplifier of around 400 watts or so. I plan on using the epx3000 to power my rti 12's and possibly (in the future) another outboard amp to run my CSi5 center channel.

FYI my vertical center channel gives me a good soundstage, although I had to boost the center levels on the receiver by 5 db's. I am hoping that my center channel will benefit from the future power boost (Gemini XGA-3000, bridged to 400 watts) and give me stronger center performance. Clarity is amazing, even whispers, at about 8 feet from listening position but beyond 10 feet or so, dialogue is difficult to understand without cranking up the receiver.

[Big Daddy]

Originally Posted by rarredoa

Sweet! Just the kind of answer I was looking for. Once I finish building the adapter (just waiting on rca jacks and banana connectors) I will use my RMS meter and see what kind of voltages I get out of the newly formed pre-outs. I was thinking of using pink noise. What do you think? What voltages should I expect?

According to the schematic I am using, the 47k ohm to 1kohm attenuation (1/4 watt resistors) should be sufficient to be used with an amplifier of around 400 watts or so. I plan on using the epx3000 to power my rti 12's and possibly (in the future) another outboard amp to run my CSi5 center channel.

FYI my vertical center channel gives me a good soundstage, although I had to boost the center levels on the receiver by 5 db's. I am hoping that my center channel will benefit from the future power boost (Gemini XGA-3000, bridged to 400 watts) and give me stronger center performance. Clarity is amazing, even whispers, at about 8 feet from listening position but beyond 10 feet or so, dialogue is difficult to understand without cranking up the receiver.

Assuming that the speaker level outputs of receivers have a voltage up to 40 volts and most amplifiers require an input voltage of approximately equal to 1 to volts, you would probably need a 20 to 1 attenuation or more (approximately 25 db's).

If you plan to bridge an amplifier to drive a speaker, make sure the speaker is 8 ohms. If the speaker is 4 ohms, don't bridge the amp as you may end up with scrambled eggs instead of an amp.

[Big Daddy]

rarredoa,

You should check the following thread. I created it partially because of your question in this thread.

http://forum.blu-ray.com/pre-pro-amp...-pre-outs.html

[rarredoa]

Originally Posted by Big Daddy

Assuming that the speaker level outputs of receivers have a voltage up to 40 volts and most amplifiers require an input voltage of approximately equal to 1 to volts, you would probably need a 20 to 1 attenuation or more (approximately 25 db's).

If you plan to bridge an amplifier to drive a speaker, make sure the speaker is 8 ohms. If the speaker is 4 ohms, don't bridge the amp as you may end up with scrambled eggs instead of an amp.

The CSi5 is an 8-ohm load, so I'm not worried. I wish I would have read your post on calculating the resistor values. I used the schematic which may or may not be suitable for my application. Either way, it's just resistors on Perf-board, so i'm not worried if I have to re-bias the circuits.

My next question is; how do I know what the speaker-level output of my receiver is? I don't recall seeing it on any specs? is the 40 volts value pretty typical for a 90 watt/channel receiver? I am pretty sure that the 40 volts is a peak value, correspondent to "loud" listening. Please correct me if I'm wrong

[Kali157]

Just wanted to say thanks BD. I had a question about amp types. Your stickies help me out quite a bit.

[Big Daddy]

Originally Posted by Kali157

Just wanted to say thanks BD. I had a question about amp types. Your stickies help me out quite a bit.

Thank you. I am glad the thread was useful.

[Sithlord75]

After some info and this seems to ideal place to ask.

I've just bought myself a new 3D LED TV & 3D blu-ray player for £1500 and I've just read that you need a 3D receiver to get lossless audio.

Please tell me this ain't the case ? And how come my current receiver can't decode the HD audio on 3D titles like it does on 2D blu-rays ?

Also, I've just upgraded my hdmi cable to 1.4. Will I need 2 of these ? 1 from player to amp & 1 for amp to 3D TV ?

Thanks.

[Big Daddy]

Originally Posted by Sithlord75

After some info and this seems to ideal place to ask.

I've just bought myself a new 3D LED TV & 3D blu-ray player for £1500 and I've just read that you need a 3D receiver to get lossless audio.

Please tell me this ain't the case ? And how come my current receiver can't decode the HD audio on 3D titles like it does on 2D blu-rays ?

Also, I've just upgraded my hdmi cable to 1.4. Will I need 2 of these ? 1 from player to amp & 1 for amp to 3D TV ?

Thanks.

If you want to use 3D, you need a 3D Blu-ray player and a receiver that is 3D compatible and supports HDMI 1.4. If your receiver is not 3D compatible, then you must bypass the receiver and connect the 3D Blu-ray player directly to the TV with an HDMI cable. Yes, you need two HDMI cables.
In order to get HD audio, you need a multi-channel receiver that supports HD audio. Almost all new receiver support HD audio. The receiver does not have to be 3D compatible. 3D is only for video.
There is no such thing as HDMI 1.4 cable. The 1.4 classification refers to the HDMI chip in the BD player and the HDMI chips in the receiver and the TV. There are two types of HDMI cables: Standard and High Speed. You need a High Speed cable for 3D video. Almost all new HDMI cables are high speed. Chances are that most HDMI cables below 10 meters will work for 3D video.

[Sithlord75]

Thanks for the info, Big Daddy.

The new 3D player i've bought has 2 HDMI slots on the back of the player, so it's good to know that i can still use my receiver an still get HD audio.

I take it i can still stick to my HMDI 1.3 cable to run from my player to amp & just use the 1.4 cable from player to TV ? Or would i still need another 1.4 cable for player to amp ?

[Big Daddy]

Originally Posted by Sithlord75

Thanks for the info, Big Daddy.

The new 3D player i've bought has 2 HDMI slots on the back of the player, so it's good to know that i can still use my receiver an still get HD audio.

I take it i can still stick to my HMDI 1.3 cable to run from my player to amp & just use the 1.4 cable from player to TV ? Or would i still need another 1.4 cable for player to amp ?

As I mentioned before, the HDMI classifications (1.3 or 1.4) refer to the transmitter and receiver chips in the player, AVR, and TV. There is no such thing as HDMI 1.3 cable or HDMI 1.4 cable. Cables are either standard or high speed. For 3D, you need a high speed cable. Almost all new HDMI cables are high speed. Your previous HDMI cable should work perfectly. Some newer HDMI cables also have Ethernet.

Read the following information about HDMI cables and HDMI versions:

http://www.hdmi.org/learningcenter/kb.aspx#49
http://www.hdmi.org/learningcenter/kb.aspx

When you're matching a Power Amp to a PA Speaker, a good rule of thumb is to pick an amplifier that can deliver power equal to twice the speaker's continuous ICE power rating.