# Building/understanding an amp/audio processer



## audionub65 (Jun 12, 2010)

Uhhh I have no clue were to start and would like to learn a bit about this. I understand the whole circuitry, I'm studying electrical engineering. What I want to know is like putting a kit together and how I would go about doing this.

What I need: 5 Channel 4 ohm support with 200 RMS per channel, and a audio processor with digital out because its coming from my PC with a subwoofer output.

Audio processor: I love the Audyssey auto EQ and would like to Incorporate this with my new audio processor?

Receiver I'm using: Onkyo HT-RC260 sounds good but just need to up the circuitry to house my new speakers I'm building that use 4 ohm load and likes power.

Thanks!


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## Jungle Jack (Jul 28, 2009)

Hello,
What kind out budget are you working with? Also, if your AVR has Preamp Outputs, you could always add an Outboard Power Amplifier and get far more power.
Cheers,
JJ


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## audionub65 (Jun 12, 2010)

Doesn't seem to support it and my budget is $300-400 and if there is something for a bit more that makes it that much better, I will take it.


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## Jungle Jack (Jul 28, 2009)

Hello,
Finding a 9 Channel AVR for 3-400 Dollars is going to be next to impossible. The cheapest 9 Channel AVR I can think of is the TX-NR1008 (B-Stock) from Accessories4less for $749. ($1,399 MSRP) 9 Channel AVR's are pretty much only offered on upper tier AVR's with 7 Channels being the norm on less expensive AVR's.
Cheers,
JJ


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## audionub65 (Jun 12, 2010)

I don't need a 9 channel, I just need 4-5 at 200 or so RMS at 4 ohm capable load. I also don't mind building a power amplifier and or a DAC to get what I need.

Note: amp like this: http://www.diycable.com/main/images/product_giant/542/inside-1.jpg 

Thanks


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## Jungle Jack (Jul 28, 2009)

DIY will provide you with tremendous value and a much better understanding of the inner workings of Amplifiers and Speakers.
Cheers,
JJ


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## audionub65 (Jun 12, 2010)

Whats the forum I should join up then to get what I need?


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## Jungle Jack (Jul 28, 2009)

Hello,
We have DIY Subforums so you do not need to leave this Forum.
Cheers,
JJ


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## Jungle Jack (Jul 28, 2009)

Hello,
We have DIY Subforums for Speakers and Subwoofers so you do not need to leave this Forum for that. As for Amplifiers, I am not sure about the best place for DIY Amplifiers, but I am sure someone will chime in.
Cheers,
JJ


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## vann_d (Apr 7, 2009)

audionub65 said:


> Doesn't seem to support it and my budget is $300-400 and if there is something for a bit more that makes it that much better, I will take it.


The power supply for 5 x 200W @ 4 ohm is going take your whole budget. You need to reconsider your budget or your power needs.


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## Jungle Jack (Jul 28, 2009)

Hello,
A used Onkyo TX-SR805 would come surprisingly close to reaching that threshold all the while offering the latest Surround Codecs, HDMI Switching, Audyssey MultEQ XT and more. The 805 is the only AVR of the 800 Series that had this level of Amplifier Power and boasted a THX Ultra2 Certified Amplifier Section. All 800 Series since the 805 have been THX Select with the exception of the 806 which did not deserve to be THX Ultra. Something Professional Reviewers made a point of bringing up.
Cheers,
JJ


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## audionub65 (Jun 12, 2010)

This is going to be used for a PC receiver and requires NOTHING fancy.

Needs: 4 ohm stable amp with 150-200 watts of power, digital in, auto calibration would be nice, subwoofer output and supports 4-5 channels.

Hope this helps narrow it down and hopefully a receiver could come close to this and I'm using this for 90% music and 10% HT.

Thanks!


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## Jungle Jack (Jul 28, 2009)

Hello,
Your stated power needs require a fairly expensive AVR or going the used route like the 805 I referred to. You could go with a Refurbished SC-07 for $699 that originally retailed for 2000 Dollars and the same Store also has the SC-37 which is the followup for $999. Both are THX Ultra2 Plus which means they are stable into 3.2 Ohms. The 37 does seem to have even more power into 4 Ohms.
Cheers,
JJ


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## audionub65 (Jun 12, 2010)

Read reviews and the 805 is the cheapest but saw there seems to be some issues with it. I thought building my own 4 channel supply/ my own receiver would be cheaper. Any other receiver suggestions? I just need something that can handle 4 ohm with 4-5 channels, digital in and sub out. I don't need anything fancy or even HDMI, just something with my specs.


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## Jungle Jack (Jul 28, 2009)

Hello,
As it is 4-5 years old, there are some that have developed issues, but the same can be said of any AVR. I purchased an 805 new the first day I could and sold it to a close friend who lives in the same city as me and it is still going strong.

The ones that have had issues have mostly been with the Display (there is a cheap DIY fix) and some with HDMI Board issues. However, there are many Members here who use it the 875 which is very similar, the 705, and other x05 Series. This includes several Moderators here.
Cheers,
JJ


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## audionub65 (Jun 12, 2010)

I will be buying the Onkyo TX-SR805 7.1 once I can sell my Onkyo HT-RC260. The amount of power and the audio on it seems the way to go as it is great at doing that.

Thanks to you all for your help!


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## Jungle Jack (Jul 28, 2009)

Hello,
The 805 remains in my mind the greatest value in the HDMI Era of AVR's. For 1000 Dollars, you got THX Ultra2, well over 100 Watts into 5/7 Channels, Audyssey MultEQ XT, and more. It honestly offers 98% of the power of most Flagship AVR's.

Such that they are several years old, I would highly recommend making sure everything works before any money is given. If the Seller has a stellar Seller Rating on Audiogon or Ebay, I might still go for it, but local would be ideal.
Cheers,
JJ


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## audionub65 (Jun 12, 2010)

Buying it used for $440 shipped on Amazon


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## Jungle Jack (Jul 28, 2009)

Hello,
That works. Amazon does provide you with a safety net even if it is a Marketplace Transaction. The 805 still is a fantastic AVR that is only lacking 3D and Networked Capabilities from keeping it from being no different than any current AVR. However, nothing for 340 Dollars has an Amplifier Section like the 805 let alone Audyssey MultEQ XT.
Cheers,
JJ


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## audionub65 (Jun 12, 2010)

Bought it for $435  Can't wait for it!


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## Jungle Jack (Jul 28, 2009)

audionub65 said:


> Bought it for $435  Can't wait for it!


Hello,
It truly is a classic. I highly doubt there will be another 1000 Dollar THX Ultra2 AVR with Audyssey MultEQ XT. It is great that you have a measure of protection by purchasing through Amazon. While I still prefer local sales when dealing with used AV Gear, this definitely seems like a happy compromise.
Cheers,
JJ


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## audionub65 (Jun 12, 2010)

I need help: I got my unit and is HEAVY and this unit produces the same amount of heat as it is on or in standby, how do I make it not be so hot when in standby?

Note: My old receiver had to turn off HDMI pass-through but can't seem to find that.
Thanks


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## Jungle Jack (Jul 28, 2009)

audionub65 said:


> I need help: I got my unit and is HEAVY and this unit produces the same amount of heat as it is on or in standby, how do I make it not be so hot when in standby?
> 
> Note: My old receiver had to turn off HDMI pass-through but can't seem to find that.
> Thanks


Hello,
That seems strange as the TX-SR805 does not have HDMI CEC Control if memory serves. Granted it has been many years since I had an 805 and only kept it for a few weeks until the TX-SR875 was available.

With my 875, that I used solely as a Preamp, I ran it 24/7 for over 3 Years. Thus, I do not have a good baseline for how much heat it generates when on Standby. I suppose if it is that hot, you could unplug it at night. It should not lose its settings if doing so.
Cheers,
JJ


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## audionub65 (Jun 12, 2010)

Is it bad that I keep unplugging and plugging in the power cord INTO the receiver? I would do this about 4 or so times a day. 


Any settings that you can recommend me to use to make it more musical other then Audyssey? Also, my tweeters are allot harsher and had to be brought down to -5 dB or so because of this (-3 by receiver and I added some). My other one didn't need any. The tweeter I'm using are $7 and plan to build new pair that will use SEAS h1212, would this alleviate the issue or is it just emphasize the higher end more?

Any other settings to reduce heat other then turning off the Audyssey EQ thing? The heat seems to becoming from the tech (terms of HDMI, plugins, speaker terminals, you name it) side of things (back left and right of receiver) and the power regulation section doesn't produce even half the heat that the tech is producing.

Note: already set my speakers to 4 ohms as I don't need all this power and my speakers are 4 ohms anyways. Were can I disable this "HDMI-Control" that is spoken in, " http://www.hometheaterhifi.com/volume_14_3/onkyo-tx-sr805-receiver-9-2006-part-5.html "

Digital out is set to Game/TV, if I change it to CD will this give me better quality sound?

Thanks


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## Jungle Jack (Jul 28, 2009)

Hello,
I would not use the 4 Ohm Setting as all it does is reduce the available power by a large amount and the 805 can handle 4 Ohm Loads in the 6 Ohm Setting. Audyssey is not a major heat producer. The reason there is not an option for HDMI Control is that your AVR predates HDMI CEC. Control allows for Passthrough of the HDMI to your TV when the AVR is on Standby and other convenience features. Something the 805 cannot do.

I had both an 805 and 875 and did not hookup a Speaker Cable to either and they still ran hot. Much of the heat is from the area around the HDMI Board. That being said, I used the 875 for 3 years and ran it 24/7 and never had an issue. If that concerned about heat, you could always add a Fan. Also, the Amp Section Bench Tested quite well in terms of S/N, etc.. Never many complaints about the Highs.

The HDMI Control they are talking about in the Review is to turn off HDMI Output altogether. It took me a second to figure that out. These days AVR's interact with other HDMI Components with one being designated the Controller. This is what HDMI Control usually means.
Cheers,
JJ


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## audionub65 (Jun 12, 2010)

Thank you so much for all your help and answering it in a timely manor. 

I'm not worried about the heat affecting the receiver, just I'm in a small room and this is producing allot more heat then what my old receiver did and just wondering if there was any way to reduce it.

I will keep the 4 ohm setting when running my speakers normally (low volume) and when I watch a movie I will switch it to 6 ohms.

How do I go about disabling HDMI altogether?

Thanks a ton!

Nick


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## Jungle Jack (Jul 28, 2009)

Just turn HDMI Monitor Off in the Setup Menu. If memory serves it is under the first Submenu.


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## vann_d (Apr 7, 2009)

audionub65 said:


> I'm not worried about the heat affecting the receiver, just I'm in a small room and this is producing allot more heat then what my old receiver did and just wondering if there was any way to reduce it.
> Nick


More power = more heat unless you change to a more efficient design unfortunately. Class A/B is just not very efficient.

Edit: nevermind... you said heat is coming from different section. You sure? Low voltage section seems weird for massive heat gen.


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## audionub65 (Jun 12, 2010)

Heat isn't being produced by the power area( giant horizontal heatsink). It is being produced by the rear left and right sections of my receiver. I decided to just add a 500 RPM fan to the rear left side were there is a small heatsink and power it off some 12 volt source inside the unit and be done with it (yes this isn't going to help my situation but will just keep the unit cooler and I have a spair fan for the hell of it). I looked around and seems this is what it is.

Thank you both and I will post anything else I find needing reiteration.


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## audionub65 (Jun 12, 2010)

Weird thing I discovered.

When I plug in my usb stick, or sometimes a change of a window the receiver automatically reduces the volume FOR my open programs. The rest of my PC (media player) or anything that wasn't part of the opening or sound will play normally. The thing that pops up and close it and open it again, it goes back to normal.

Rephrase: plug in a USB,my audio all turns down a notch. Until I close the program (my movie program, or a audio program or YouTube or anything that plays audio or video) and start it back up, the volume will stay lowered.

Hope this makes since as this is a weird thing that I never experienced before and gets quite annoying (some programs be a higher volume some are lower).

Note: Also when my media player is open and I unplug the cord, the volume stays low until I re-open my media player.

Hope this makes sense.

Also, can I start to unplug the HDMI board or the other boards that aren't needed without damaging my receiver? I want to do this to reduce heat, prolong the life of my receiver and do it for the hell of it .


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