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.
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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
testpilot
922 posts
 
@ramtubes, how do you make a power cord that blocks DC?
clio09
3,354 posts
 
ramtubes - So, you don’t believe power cables make a difference other than connectors and isolation transformers are worthless? Is that correct?

I don’t think he is saying connectors make a difference sound wise as some people might lead you to believe. In other words a Furutech connector won’t sound any better than an Oyaide connector. He is saying just use good ones. For me that means the ability to get a snug fit with the outlet (I use Hubbell hospital grade) and a means to make a good connection with the wire (I use off the shelf "Oyaide" connectors I buy on Ali Baba).
eldiablokid
1 posts
 
Hello
 How can I use a Plinius SA 250 amp setup for 230v in the USA, thanks John 
ieales's avatar
ieales
1,201 posts
 
Sorry to say this is a horrible product.
Ouch!
Power in Los Angeles could be very problematic.
I added a 5300 in about 2003 and it was a significant improvement even though my amp had an internal LC power filter. At the time, I auditioned 2 Panamax, 2 Monster and 1 Furman. The Furman was best, followed by the 5300, then the Monsters and Panamax. Each added it's own coloration.

15 years later in Oregon with different electronics, it still works and I like what it does. Cable and other jacks remain unused.



atmasphere's avatar
atmasphere
11,781 posts
 
JA measured a low 84dB sensitivity but with a higher/smoother impedance he deemed them "a very easy load for the partnering amplifier to drive."
@prof
Tube amplifier power has traditionally been expensive. Inefficient loudspeakers as mentioned above only became possible in the era of solid state since that power is so much cheaper. Unless you are in a very small room, I'd consider a different speaker as 140 watts isn't a lot of power when dealing with a sensitivity that low, regardless of the 'difficulty' of the speaker.

@clio09

this is the power cord he was referring to that does make a difference under certain circumstances:

http://tubeaudiostore.com/pocoyoucanac.html

Otherwise as Roger noted in his last post just get a cord with good connectors.

Apparently though Roger sees or saw fit to build his own power cord setup using some pretty heavy gauge wire (see page 12); this suggests (if actions speak louder) that he does think they make a difference, else why go through the bother?

(FWIW a power cord with light gauge but good connectors will not bring home the bacon, generally speaking. I've seen power cords, not just the connectors, heat up.)


I first heard how dramatic a power cord can be at the 1990 CES in George Cardas' room. The impact and nature of the bass was easily heard by all present to be quite different and with more impact when stock power cords were replaced by a pair that George offered. I found it disturbing; at the time I just didn't understand what was happening (and it clearly was not snake oil as it was repeatable) but I also knew enough to not buy the explanations that were offered (which clearly **were** snake oil).


But in time I found out that all you have to do is to simply measure the effects a power cord has on an amplifier. Generally speaking, the more power the amplifier draws, the more you will hear differences between power cables. 
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