Crown

[SteveJewels]

That is good to know. Techron amps are used in my work, I see them all the time.

One of the tests we do to electronics for commercial aircraft is to generate audio frequency interference and either couple it through a transformer onto the power input line. Aldo we create either an electrical or magnetic field and expose the avionics to that.

[RMC]

Hi Lost...,

Since you requested it in post # 14, and considering the fact I see No copyright indication anywhere on the document, here's a picture of the Crown ad. No sledgehammer anywhere in the pic though! Bottom left, talks about "...bone-rattling bass..."

Because its been pinned for 20-25 years or so, maybe more, on a wall in my audio room, along with many others from different equipment makers, it has changed color a bit over the years...

Funnily, bottom right of the page, Omnimedia Corp. Crown's Canadian distributor at that time was previously the distributor of BGW amps in Canada for many years, as well as Gauss and others. Regards,

Richard

[Earl K]

Great News Barry about AE Techron servicing Crown.

Thanks for sharing that!

[SteveJewels]

I use Crown amps to power my turntable. 🙂🙂🙂🙂🙂

[LostInTennessee]

Thanks RMC for posting the add. I own 2 PS-400, 5 D150A Series II, 3 D150A, 3 IC-150A, 1 SL-2, 1 SL-1 (AMCRON version), DC300A, and 2 XLS 1000. Big Crown fan here....

[1audiohack]

I use Crown amps to power my turntable. 🙂🙂🙂🙂🙂

What do you use for a signal generator?

Barry.

[SteveJewels]

What do you use for a signal generator?

Barry.

For version one, which is the version that was working when I last had it setup, I used a Hewlett Packard/Agilent 33120a. It is an arbitrary waveform generator.

It has Option 1, the high stability time base which is frequency stable to 1 part per million per month.

Version two, which I will set up when I get the gear to Rockford, uses two of the Arb Gens linked together. They have the ability to run one as the Master and the other as the Slave so that I can remove the phase shift capacitor from the turntable motor and power the two sets of poles separately. The slave Arb Gen can be adjusted to be phase delayed relative to the Master.

I haven't figured out how I will determine the optimum phase shift to use nor how to monitor it. I do know that more phase shift (as induced by the capacitor) is needed to start the motor than is needed to keep it running. I am hoping that I will be able to determine by listening the optimum phase shift needed to minimize lobing. Here is a link to a paper on ESA, Electrical Signal Analysis, of electric motors. https://oaktrust.library.tamu.edu/bi...=1&isAllowed=y

By using Arb Gens, I can also program the shape of the 'sine' wave. It is possible that having a more rounded shape to the top of the wave may reduce the lobing effect.

Using Arb Gens will also eliminate the inherent V vs I phase shift that occurs when a sine wave voltage passes through a capacitor. If V and I are in phase before the capacitor, I will lead V after the capacitor, adversely affecting the Power Factor. A Power Factor of 1 is when V and I are in phase. Anything less than 1 is undesirable. ELI the ICE man is everywhere. LOL

I grabbed a pic of a Techron 7700 we are presently using in the lab to generate electric and magnetic interference to test avionics for a 777X. I will post it when I get a chance. 2,585 watts into a 2 Ohm load. Several can be ganged together if you need more power.

[SteveJewels]

Techron 7700

[1audiohack]

….I haven't figured out how I will determine the optimum phase shift to use nor how to monitor it. I do know that more phase shift (as induced by the capacitor) is needed to start the motor than is needed to keep it running...

Thinking out loud, and simplifying as I go, if the motor is elastomer mounted, make contact with anything perpendicular to the shaft on its case with the stylus of an old turn table and o scope the magnitude of the lobing forces in the shell, adjust phase to minimum? See, I really am a hack.

I grabbed a pic of a Techron 7700 we are presently using in the lab to generate electric and magnetic interference to test avionics for a 777X. I will post it when I get a chance. 2,585 watts into a 2 Ohm load. Several can be ganged together if you need more power.

I love those things! I have four 7782's, perfect for audio.

interesting link on motors, still chewing through it.

Barry.

[SteveJewels]

It has been a while since I have torn it apart but IIRC the motor is hard mounted. Here is a pic;



I was thinking of trying a 3 axis accelerometer, using just X and Y and adjust as you suggested, for minimum vibration.