2. amps-preamps
  3. 140029-80294

Does anyone care to ask an amplifier designer a technical question? My door is open.

I closed the cable and fuse thread because the trolls were making a mess of things. I hope they dont find me here.

I design Tube and Solid State power amps and preamps for Music Reference. I have a degree in Electrical Engineering, have trained my ears keenly to hear frequency response differences, distortion and pretty good at guessing SPL. Ive spent 40 years doing that as a tech, store owner, and designer.
.
Perhaps someone would like to ask a question about how one designs a successfull amplifier? What determines damping factor and what damping factor does besides damping the woofer. There is an entirely different, I feel better way to look at damping and call it Regulation , which is 1/damping.

I like to tell true stories of my experience with others in this industry.

I have started a school which you can visit at http://berkeleyhifischool.com/ There you can see some of my presentations.

On YouTube go to the Music Reference channel to see how to design and build your own tube linestage. The series has over 200,000 views. You have to hit the video tab to see all.

I am not here to advertise for MR. Soon I will be making and posting more videos on YouTube. I don’t make any money off the videos, I just want to share knowledge and I hope others will share knowledge. Asking a good question is actually a display of your knowledge because you know enough to formulate a decent question.

Starting in January I plan to make these videos and post them on the HiFi school site and hosted on a new YouTube channel belonging to the school.


128x128ramtubes
brownsfan
1,508 posts
 
@atmasphere,
"I don't use the word 'believe' because I made the measurements which showed that the power cord **without question** can affect the amplifier's performance. The measurement is easy- the voltage drop from one end of the power cord to the other. Its not rocket science and its not mumbo jumbo woo. Anyone with a 3 1/2 digit DVM can do it. After you know what the voltage drop across the cord is, then measure the resulting differences in the amplifier: output power, distortion and output impedance. You will find that they all change. So by this simple means you have a tool to correlate with what you hear.  So in a nutshell, I don't believe it, I **know** it."

Ralph, thanks for providing this insight.  I have been accustomed to thinking about power supply to amplifiers primarily as avoiding reduced current supply, not avoiding voltage drop.  I had not really considered voltage drop before.  I was especially intrigued by your statement regarding measurability of differenced in distortion as a consequence of voltage drop.  My power usually measures around 120-123V from the duplex, in other words, it is a bit on the high side.  I run my system through a PS Audio P-10 with the voltage set at 117 V (tube life!) , but my M-60s are supplied straight from the wall.  They are not happy running through the P-10!  From the point of view of distortion from the M-60's as a function of voltage, would you expect a measurable difference in distortion over the range of 115-125 Volts?
jaycawley
1 posts
 
Hello. I have a McIntosh mono block 501 that is hard blowing fuses
when I turn it on. Ideas? Thanks.
ramtubes's avatar
ramtubes OP
460 posts
 
* Discussion on diode transients and measurement thereof here:  https://electronics.stackexchange.com/questions/323507/bridge-rectifier-4-diodes-vs-single-chip


Not much meat or it sounds. I didnt read the whole thimg. In my RM-5 preamp I found the coupling of the power transformer to make a great difference. A well coupled primary has less noise, however a loosely coupled primary was worse. Takes some digging to see this. 

I felt it best to use the Grid to take the pulses. What a cord might do I, dont think much.

I would like to see some scope photos of these diodes compared to others all the way down to the slow 1N4000 series.
atmasphere's avatar
atmasphere
11,861 posts
 
my M-60s are supplied straight from the wall.  They are not happy running through the P-10!  From the point of view of distortion from the M-60's as a function of voltage, would you expect a measurable difference in distortion over the range of 115-125 Volts?
You would certainly be able to measure a difference, not just distortion but also power.

It seems that conditioners like the P10 are not happy with higher constant loads on them- they work fine with higher power solid state amps that have otherwise low quiescent current draw, but tube amps with larger draws (for filament circuits, perhaps also class A) seem to cause them trouble. For that reason we usually recommend running the amps straight out of the wall.
If you want a really nice conditioner, a company called Elgar used to make some that are quite impressive.
ffzz
26 posts
 
A couple tech questions for Roger. Others please chime in too.

Is it possible to estimate how much amp power will be enough (i.e. never clipping) simply based on speaker specs (assuming they are correct), and listening habit/situation (i.e. distance from speakers, loudness)? 

If so, how?
More to discover