JohnRoberts

Re: Studio Monitor Power Amp
« Reply #20 on: January 22, 2013, 12:19:23 PM »
While there is plenty of negative feedback to reduce the impact, a class D power amp is effectively PWM modulating the power supply DC voltage to make audio AC, so indirectly the PS quality matters.

I don't wish to overstate the importance, but everything matters.

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.


tv

Re: Studio Monitor Power Amp
« Reply #21 on: January 23, 2013, 05:02:39 AM »
This is at least equally important with class-AB chipamps, from the small 5-watters to their bigger variants.

If you sprinkle when you tinkle, please be neat and wipe the seat.

ppa

Re: Studio Monitor Power Amp
« Reply #22 on: February 02, 2013, 04:19:21 PM »
just for info,

I have a mosfet amp module (that I have designed) soon available rated of 100W/8ohm 180W/4 ohm on AB class. Seems that it sound good, a friend of mine said me that he prefers it to his Perreaux amp.

Moreover should be available the chassis too, it is a 2U type. 
 
Pier Paolo     


PS: just if someone wants to try it.
« Last Edit: February 02, 2013, 05:04:17 PM by ppa »

ppa

Re: Studio Monitor Power Amp
« Reply #23 on: February 02, 2013, 07:30:28 PM »
moreover is not so complicated to assembly as you can see in the photo, but, in any case, is not for beginners, we are speaking of a 180W/4ohm amp.
 

Moby

Re: Studio Monitor Power Amp
« Reply #24 on: March 26, 2013, 08:59:32 PM »
Hypex amps are realy great. I have 10 different modules installed in my studio and all of them works cool. To be honnest, they don't sound like Bryston but amps every buck I payed   :)
For microphone transformers,  BV.8,  Bv.11,  Bv.12, etc.. contact me at mobyelectronics at gmail dot com

JohnRoberts

Re: Studio Monitor Power Amp
« Reply #25 on: March 26, 2013, 10:09:23 PM »
Hypex amps are realy great. I have 10 different modules installed in my studio and all of them works cool. To be honnest, they don't sound like Bryston but amps every buck I payed   :)
Great.. Amps aren't supposed to sound like anything...  Bruno did well..

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

alexc

Re: Studio Monitor Power Amp
« Reply #26 on: March 27, 2013, 06:27:31 AM »
Speaking of pwm modulating of the power supply, didn't that early Carver amp achieve that thru mutually transduced magneto constrictive means?

I seem to recall, many years ago it was a big deal - modulating the psu by means other than  ..  transistors ..

Is there a relation to the class d digitally modulated things of today?

-- my amp is bipolar.
-- my other amp has tubes :)
I ping therefore I am

Moby

Re: Studio Monitor Power Amp
« Reply #27 on: March 27, 2013, 08:44:09 AM »
Hypex amps are realy great. I have 10 different modules installed in my studio and all of them works cool. To be honnest, they don't sound like Bryston but amps every buck I payed   :)
Great.. Amps aren't supposed to sound like anything...  Bruno did well..

JR
Sorry for my poor English , I wanted to say that Bryston sounds a bit more accurate but Hypex plays great for that money :)
For microphone transformers,  BV.8,  Bv.11,  Bv.12, etc.. contact me at mobyelectronics at gmail dot com

JohnRoberts

Re: Studio Monitor Power Amp
« Reply #28 on: March 27, 2013, 09:46:14 AM »
Speaking of pwm modulating of the power supply, didn't that early Carver amp achieve that thru mutually transduced magneto constrictive means?

I seem to recall, many years ago it was a big deal - modulating the psu by means other than  ..  transistors ..

Is there a relation to the class d digitally modulated things of today?

-- my amp is bipolar.
-- my other amp has tubes :)
AFAIK Bob Carver has not made PWM amps unless he did something recently. His old marketing has included gobbleygook about transformers I think he was an early adopter of Bridge mode and Class G/H for high power and efficiency. A little poetic licenses to talk about transformers being involved in multi-rail amps.  8)

While Bob deserves both credit and demerits for his early Flame linear work, (Good for relatively high power back in the day, bad for inadequate output device protection, that made them easy to kill).

I still get a chuckle over his Stereophile shootout where the matched the transfer function of some uber expensive audiophile amp with his cheaper transistor amp...  Amplifiers are a mature technology and when properly executed far from the weak link in any audio chain. Most of the recent progress in amp technology is making them bigger/cheaper/more efficient.

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

alexc

Re: Studio Monitor Power Amp
« Reply #29 on: March 28, 2013, 06:37:35 AM »
Here's a link to an interesting paper by Bob Carver - covers the 'magnetic field effect' amp and tailored transfer functions  :)

http://carvermk2.com/Docs/Carver%20Magnetic%20Field%20Whitepaper.pdf

Seems the magnetic thing was a triac circuit in the psu traffo primary.
« Last Edit: March 28, 2013, 06:40:47 AM by alexc »
I ping therefore I am


JohnRoberts

Re: Studio Monitor Power Amp
« Reply #30 on: March 28, 2013, 10:50:04 AM »
Here's a link to an interesting paper by Bob Carver - covers the 'magnetic field effect' amp and tailored transfer functions  :)

http://carvermk2.com/Docs/Carver%20Magnetic%20Field%20Whitepaper.pdf

Seems the magnetic thing was a triac circuit in the psu traffo primary.
Thanks I knew there was a reason I was blocking that out... Bob is a very clever guy but the marketing who hah in that "white paper" gives white papers a bad name.

As I suggested the amp uses multi-rail supply AKA Class H and invented by Hitachi IIRC.  Using a light dimmer circuit on the transformer primary to scale for 2/4/8 ohm load seems clever, several amps would use different transformer windings.

The "Magnetic Amp" is more clever branding than descriptive of what is going on, but the amp did squeeze a bunch of music power from less iron/aluminum.  For a while Clair Brothers, used these for serious sound reinforcement, but as Clair Brothers often do they modified the amps with bigger PS caps and IIRC replaced the power switch or something odd like that.

Bob is a good engineer and his appreciation for importance of transfer function is more important than this trick amplifier that burned across the consumer market like a meteor.

If I wasn't busy I would search out his patent, but trying to make sense of his ad-speak using a triac on the transformer primary as a "regulator" has limitations. Triacs are like the hotel califorina, you can turn them on, but you can't turn them off. You need to wait until the AC waveform returns to zero, so like a light dimmer, you adjust where you turn it on on the already falling waveform to get a lower voltage. Unfortunately if the music decides that it wants more voltage instantly, you need to wait until the next mains cycle , say 8mSec for FW rectified supply.

But a clever overall design, that I tend to under-appreciate because of the hyperbolic marketing. The scary part is I suspect Bob was involved in that too. He struck me as a little frustrated as he mastered the amplifier technology better (IMO)  than effectively dominating the marketplace, while he did quite well for a time (several times).

JR

PS: on my list of related amplifier tricks, that I never got around to doing, and now never will because Class D makes them all moot, was an idea to add a similar back slope regulator on the secondary to vary just the lower intermediate PS rail of a class  G/H amplifier. On the secondary side I could literally pull less voltage from the same single high voltage winding, delivering on the promise, Carver hinted at (crude power factor improvement). I used this variant synchronous rectification trick in my Loftech TS-1 power supply back in the '80s to pull a high current 5V supply from a 15V winding without wasting 2x the power as heat in a pass regulator. This amp low voltage/power rail could be regulated based on actual musical demand to make the amplifier very efficient by sizing it to match the music demand closely. The high rail is always sitting there charged up and ready to meet sudden transient needs. The low rail can be brought up higher in several mSec as needed so you don't give up all your efficiency running off the high voltage rail for more than a few Msec. A good idea for maybe a few decades ago, not so much now.  :'(

 
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.


 

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