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My Sure IRS2092 Amplifier Build

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  • Wolf
    replied
    Re: My Sure IRS2092 Amplifier Build

    Originally posted by robertcottiers View Post
    OOPs...I have just been pulled over by the router bit police

    BTW : If you happen to See/Hear from Shawn A(alias bigfoot)tell him I said hello,he does not appear to have a valid e-mail anymore.

    Bob
    I let him know you're about....
    He does have a newer addy than you likely have.
    Later,
    Wolf

    Leave a comment:


  • robertcottiers
    replied
    Re: My Sure IRS2092 Amplifier Build

    OOPs...I have just been pulled over by the router bit police

    BTW : If you happen to See/Hear from Shawn A(alias bigfoot)tell him I said hello,he does not appear to have a valid e-mail anymore.

    Bob

    Leave a comment:


  • Wolf
    replied
    Re: My Sure IRS2092 Amplifier Build

    Originally posted by robertcottiers View Post
    do is use a cove bit on either side of the power switch and a simple chamfer around the perimeter....

    Bob
    Actually- that would be a 'core-box' router bit, not a cove. Coves imply using an edge with the bearing guide, whereas, the Core-Box bits require you either use a router table or an added/clamped straight edge to guide your router/wood.

    Agreed on the Forstner bits....

    Later,
    Wolf

    Leave a comment:


  • hongrn
    replied
    Re: My Sure IRS2092 Amplifier Build

    Thanks Neil, you ARE the amp sifu...

    Leave a comment:


  • neildavis
    replied
    Re: My Sure IRS2092 Amplifier Build

    Originally posted by hongrn View Post
    I hope Neil will chime in to answer your question #1 about the voltage requirement versus output, but yes, the higher the voltage, the higher the output. The Sure amp is built for rail voltage between 55VDC and 65VDC, and exceeding 65VDC will shut it down.
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    The other thing to consider is the behavior with lower impedance loads. The most important specification to consider for an amplifier is the safe operating area (SOA) of the output devices. The SOA curve for the output devices used in the reference amp is shown in the second attachment. What's most important about this curve is that it shows how you can have high voltage across the device at reduced currents, or high current at low voltages, but you can't have both high voltage and high current (which would be "outside" the dashed lines). The SOA curves are for single pulses, and it's not clear how you would select the curve for a class D amp, where the pulses are repetitive, but the key take-away here is that the amp will be able to deliver more current with low voltage rails. For example, if you run the amp with 50V rails you would only get (50/1.41)^2/8, or 157W for an 8 ohm load. However, at that lower voltage you could use a 4 ohm load and still stay safely within the SOA curve. At 4 ohms, the amps will put out a bit more than 250W, according to the measurements in the IR reference design document. So that's another reason for accepting the Sure product as a 250Wx2 amp.
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    Kind of a wordy answer, but hopefully the technical issues are clear. The simple answer is that the board is in the 250Wx2 class, and how much power you *actually* get depends on the supply voltage and the load.

    Leave a comment:


  • arlis_1957@yahoo.com
    replied
    Re: My Sure IRS2092 Amplifier Build

    I built one with a 40-40 and ended up with 60.3vdc. Its really nice.

    Leave a comment:


  • jsr
    replied
    Re: My Sure IRS2092 Amplifier Build

    Ha forgot about the rms thing. Told ya it was stupid. Thanks guys.

    Leave a comment:


  • hongrn
    replied
    Re: My Sure IRS2092 Amplifier Build

    I hope Neil will chime in to answer your question #1 about the voltage requirement versus output, but yes, the higher the voltage, the higher the output. The Sure amp is built for rail voltage between 55VDC and 65VDC, and exceeding 65VDC will shut it down.

    On question #2, transformers are rated in AC voltage, which is rectified to DC voltage through a bridge rectifier. To figure out the DC voltage, you take the AC voltage and multiply it by 1.41. Since the maximum DC voltage for the Sure amp is 65VDC, 65/1.41=46, you can theoretically pick a transformer with 45VAC secondaries for the amp. However, keep in mind that house voltage can vary by as much as 10%, so there's a chance the rectified voltage may go over 65VDC, triggering the amp to shut down. That's why I picked a transformer with 40VAC secondaries, rectified to 56.4VDC (40x1.41=56.4) to power the amp and stay within its voltage requirement. I hope this helps.

    Originally posted by jsr View Post
    Some stupid questions from a stupid person (um...me)...so be gentle...

    I can't find any power info on the IRS2092 datasheet. From what I've seen with chip amps, the power is directly related to the supply voltage. It appears the IR reference design to get 250W at 8ohm requires +/-70V. The Sure uses 55 to 65V rails, but claims the same power (250W into 8ohms). Is the Sure making that or is it lower power (such as at the +/-56V used here)?

    Stupid #2: Does the power supply boost the transformer's voltage? I thought it just provides filtering, but the output of Hong's transformer is +/-40V while the PS output is +/-56V.

    Thanks.

    Leave a comment:


  • JimHRB
    replied
    Re: My Sure IRS2092 Amplifier Build

    Regarding #2, the transformer voltage is VAC which is RMS. The DC output is the peak voltage (1.41 times VAC RMS) after rectification and the large caps.

    Leave a comment:


  • jsr
    replied
    Re: My Sure IRS2092 Amplifier Build

    Some stupid questions from a stupid person (um...me)...so be gentle...

    I can't find any power info on the IRS2092 datasheet. From what I've seen with chip amps, the power is directly related to the supply voltage. It appears the IR reference design to get 250W at 8ohm requires +/-70V. The Sure uses 55 to 65V rails, but claims the same power (250W into 8ohms). Is the Sure making that or is it lower power (such as at the +/-56V used here)?

    Stupid #2: Does the power supply boost the transformer's voltage? I thought it just provides filtering, but the output of Hong's transformer is +/-40V while the PS output is +/-56V.

    Thanks.

    Leave a comment:


  • robertcottiers
    replied
    Re: My Sure IRS2092 Amplifier Build

    I may have started it but you guys are going to finish it...Gentleman start your routers :D

    Bob..Watching from the bleachers

    Leave a comment:


  • hongrn
    replied
    Re: My Sure IRS2092 Amplifier Build

    Great find Ron. See what you started Mr. Bob?

    Leave a comment:


  • Ron_E
    replied
    Re: My Sure IRS2092 Amplifier Build

    Originally posted by hongrn View Post
    Bob,

    1. How is the Corian sold? How large a piece does it come in?
    2. Can it be cut with a regular table saw?
    3. How do you polish it?

    Thanks.
    This site has small Corian pieces. http://solidsurface.com/sheet-materi...rder/sqft_sort

    Ron

    Leave a comment:


  • robertcottiers
    replied
    Re: My Sure IRS2092 Amplifier Build

    Great deal there Neil.. $4 is dirt cheap.

    Bob

    Leave a comment:


  • hongrn
    replied
    Re: My Sure IRS2092 Amplifier Build

    Thanks Don. I didn't know Corian generated that much dust.

    Originally posted by donradick View Post
    I just researched this in depth - you can find smallish corian pieces on Ebay pretty cheap that are good for faceplates or backpanels.
    You can even find cheap corian cutting boards for larger pieces.

    There are a number of threads here on PETT about working with corian. Consensus I got is that carbide router bits work well,
    but be sure to wear breathing protection.

    HTH,

    Leave a comment:

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