[mikeeastman]

I'm burning in an amp and right now I have a CD player straight into amp with no vol control what would the vol  level be at, full , 1/2, no? Amp out is connected to dummy speakers.

[*Scotty*]

Tell us the amp make and model. Why? Well, a CD player frequently has a max output level of 2volts or more. The amplifier's input sensitivity may be less than 2volts in for full power output. For example, I have a couple amps that have an input sensitivity of 1volt in for full power output. If I hooked up a CD player straight in to these amps they would spend a LOT of time in clipping and might fail due to excessive heat in the output devices.
 This is where it pays to know the input sensitivity of the amplifier before you do something like this for burn in. I would use a preamp to attenuate the signal in situations like this to something I know doesn't produce more than a ordinary SPL from my loudspeakers with no clipping.
Scotty

[FullRangeMan]

Usually CD players are 2V on RCA outputs.
There was a odd NAD player that was 5V to drive big SS amps as Krell.

[Speedskater]

Remember the old US power amp test.  The 1/3 power warm-up period was often the most demanding part of the test.
While a modern amp might require a short warm-up, they don't burn-in.

[mikeeastman]

Thanks for the replies. I couldn't find input impedance ,so just dug an old pre out of the closet and set at 1/2 vol and called it good.

[YoungDave]

I couldn't find input impedance ,so just dug an old pre out of the closet and set at 1/2 vol and called it good.

I sure would not do that.  I'd be looking for between 1/2 and 3/4 of the maximum rated power output at the music peaks, significantly less than that for the music average level.  At any rate, I cannot advocate running an amp at some unknown output level at all.  Besides, burn-in is not that important - but if it was, don't you think it might be important to do the burn-in right?  It is hardly likely that just running music at an unknown level is going to be right...

I've built a number of amplifiers and tested many more.  You simply have to know the maximum output level (in voltage, not power) so that you can measure and set the levels you want to achieve.  A scope, spectrum analyzer, and (as a minimum) an AC voltmeter are required here.

[*Scotty*]

Mike what amp are you breaking in?
Scotty

[mikeeastman]

Mivers icepower 1200AS. The amp itself probably doesn't need much burn in but there are the new wire and connecters, also I added high-pass caps ( Jupiter copper foil ) to my Mivera pre and they need min 200hr but really like 400hr for full burn in. I want them both to have 200hs before I give them a listen. I'll probably lose patience around 150 hr and take a listen though.

[poseidonsvoice]

Mivers icepower 1200AS. The amp itself probably doesn't need much burn in but there are the new wire and connecters, also I added high-pass caps ( Jupiter copper foil ) to my Mivera pre and they need min 200hr but really like 400hr for full burn in. I want them both to have 200hs before I give them a listen. I'll probably lose patience around 150 hr and take a listen though.

I've posted answers that are relevant to this question numerous times on Mivera's forums but it gets lost in all the off topic posts.

The overall gain of the 1200AS is 26dB.

The input sensitivity to reach max power (which is ~ 600 watts/8 ohms or ~ 1200 watt/4 ohms) is about 3.5V RMS. 600 watts or 1200 watts into those respective impedances is about 69V RMS.

The input sensitivity to reach 311 watts/8 ohms or 622 watts/4 ohms is about 2.5V RMS. 311 or 622 watts is about 49.9 V RMS.

Obviously an input of  0.25V RMS then into the Mivera 1200AS amplifier is about 4.99V rms output which is about 3 watts/8 ohms or 6 watts/4 ohms.

If you used a CD player with 2V RMS (or higher) into the Mivera amp, connected to 'dummy speakers' without a preamp/volume control to drop that 2V RMS to something miniscule (like 0.25V rms), you will destroy your dummy speakers, your ears or both.

Best,
Anand.

[mikeeastman]

Dummy speakers just resisters in a box so my ears would be safe.  I wasn't sure, so I add pre so all is well.

[rollo]

  I have yet to demo a class "D" amp that did not take 400 to 500 hours to settle. Use 8 OHM resistors instead of speakers to break in. It is also a good thing if one owns an old DVD or Cd player  or music server to use as source. Save your lasers.
BTW I recommend 12 hours on 12 hours off. The dielectrics are what need time to form. Then there is that module. Takes time. Be patient.


charles

[poseidonsvoice]

Dummy speakers just resisters in a box so my ears would be safe.  I wasn't sure, so I add pre so all is well.

Make sure the resistors (preferably wirewound) are rated for twice or thrice the output power so they run cool or have a small heatsink attached to them. If you are using music for the break in, they probably won't get too warm.

I usually use 25 watt dummy resistors (not speakers!), and use a preamp, where I turn it down and measure the output voltage to about 100mV (0.1V) to 250mV (0.25V) RMS.

I used to  have a CD from Hagerman, called the FryBaby which had a track where a sophisticated electronic waveform was recorded – a combination
of wideband noise and variable frequency amplitude modulation, and I would run that on repeat.

Now, I use my DIY based Hagerman Frykleaner:




I set it to the lowest output voltage of 0.25V rms (toggle in above pic, set to LO), connect that directly to my amp, attach 25 watt dummy resistors to the output binding posts and let the amp 'break in.' I can break in cables, capacitors, amps, preamps, whatever I want pretty much. I use it for testing as well to see if any of my DIY designs blow up 

http://www.hagtech.com/pdf/fryklean.pdf

Best,
Anand

[jtwrace]

You can use these too.


https://www.parts-express.com/cat/dummy-load-resistors/1535

[poseidonsvoice]

You can use these too.


https://www.parts-express.com/cat/dummy-load-resistors/1535

Fantastic stuff, I've looked into those too...

Best,
Anand.

[rollo]

  Ah the Franken fryer good unit. Fry away and don't forget the shrimp


charles

[mikeeastman]

That is the dummy speaker I was using, but you guys got me worried so I hooked an old pair of ADS 200ies I had in my closet. I'm actually using my DVD/ SACD player I only use to watch DVDs as I've not played an actual cd for over 4 yrs, I only listen ripped CDs so I don't care about the laser. The sound is not bad considering the player and speakers.