My new favorite amplifier?

Post by **Eric D** » Thu Feb 09, 2012 5:08 pm

For those of you who know me, you know I have fixed a lot of amplifiers, and I have heard a lot of amplifiers. Sure, plenty of other people have heard more than I have, or have fixed more than I have, but most anyone would agree, my exposure to amplifiers is above average.

Well, today I finished repairing a Focal 4.75 (which belongs to a member here). I was shocked to say the least.

Now, don't get me wrong, this is the PG forum, and I am still a die hard PG fan. I just feel obligated to mention anything I come across which jumps out from the rest of the pack.

This amp is one of those.

When I first opened it up to repair it, I was not too impressed with the guts. They are simple. Nothing special, and no parts which I have not come across in other amplifiers before. There are two transformers for the power supply, but it is still just a big single power supply. It uses 4 TO-247 MOSFETs for the power supply, and two TO-247 sized BJTs for each of its 4 channels.

I am guessing the amp is made in the same factory as the PG Ti line is. The terminals look to be identical (keyword "look"), and many other aspects of its build quality look similar to the PG.

Power wise it is rated at 75W x 4, and I found it to be around 80W a channel, so nothing special there either.

SQ is where this amp shines. I have been using the same test bench with the same equipment for years now. And I have found it to all be very consistent. I also listen to a lot of the same CDs when testing amps, so I am pretty used to the tracks I have heard so many times. As soon as I started playing this amp it sounded different. I could not place what was different, but something was different. I did not have any reason to really like this amp, so I figured it could not be my mind playing tricks on me, but I kept telling myself it was just in my head.

Then it hit me. I have listened to one CD from Nine Inch Nails in particular MANY times with other amps. It is pretty much my reference CD. I listen to it over and over on my test bench. Well after years of playing this CD there were plenty of points in songs where I had no idea what the lyrics were. Even after all that listening I could not make out certain words, they just blended into the music. With this Focal 4.75 I could hear the words cleanly and obviously. I know this is was not an A-B comparison, but I am still shocked at how much detail this amp exposed.

So, I guess the bottom line is I am very impressed with this amp. Am I going to run out and buy a bunch, no. Is it better than PG? Maybe it is better than some amps from PG, but I still like my PG amps plenty.

So, the real reason I am posting this is I just look forward all that much more to the new Elite amp lineup, and how they have what it takes to spank this Focal.

Post by **kg1961** » Thu Feb 09, 2012 5:54 pm

glad you so happy with her now lets talk so you own her

Post by **joerg** » Thu Feb 09, 2012 11:52 pm

Finally Eric backs up what i was telling u all the time, Mike! Focal always was the only brand i´ve choosen over Phoenix Gold since Phoenix Gold got past the ZXTI line. But i´m curious as well when it comes to the new Elite Lineup.

Mr. Wild · Post by **Mr. Wild** » Fri Feb 10, 2012 3:10 am

We are talking about differences which cannot be measured. Not freq. response or THD or S/N ratio. These differences really seem to exist even though many don't believe in them.

I wonder what it is that makes a good amp? PG are "high definition" amplifiers but maybe the Focal is even higher definition. In a pic from ampguts.com I found, there doesn't seem to be any op amps in the main amplifier section. Could this be any part of the good SQ?

http://ampguts.com/forum/attachments/fo ... 53f227-jpg

BTW is the focal triple darlington? Looks like it might be.

Post by **Eric D** » Fri Feb 10, 2012 3:53 am

All I can guess is the amp has really high damping factor or something to help control the speaker better.

The best amp I have ever heard was the Soundstream Class A Picasso. I actually did an A-B comparison between it and a few other amps, it easily won every time. I no longer have that Picasso to compare, but I am guessing this Focal amp will be similar. As a bonus the Focal has a much bigger and better power supply. The Class A Picasso has a VERY weak power supply.

I wish there were some way to quantity the results I got, but I can think of none. It still has me in disbelieve I could hear the lyrics in a song I have heard probably 100 times and finally understand them.

I should also add this, the Focal seems to have many of the same parts as older Zapcos do. I have a small older Zapco, and it is also one of my "reference" amps. The Zapco sounds every bit as good as the Class A Picasso, just with a lot less power output.

Both the Focal and the Zapco use TIP BJT outputs. I think there are TIP36s in there and the opposite matching transistor as well.

Post by **Eric D** » Fri Feb 10, 2012 4:00 am

I just remembered something else which may be why this amp sounds better.

After fixing the amp I put it on my new oscilloscope (yes, I bought another oscilloscope), and looked at its output. When I ran the amp up to clipping, it would "soft clip". Even well beyond the range of what the amp can do, it would round off the corners on the signal by a significant amount. PG amps don't do this, RF amps don't do this, actually I have not seen any other amp do this.

Well, I think this may be a sign the amplifier has HUGE amounts of feedback. So much feedback, that when the output becomes significantly distorted, the amplifier does everything it can to force the signal back to its original shape. A lot of people don't like amps with high amounts of feedback, but maybe that is why this amp is better.

Also, considering the amp was fed 13.8V of input and I got just under 80W a channel out of it, I would say the amp is highly regulated. I am sure it will keep its performance under a wide range of battery voltages.

Post by **kg1961** » Fri Feb 10, 2012 6:03 am

so does anyone want to buy this amp? i have to talk with Eric about what it cost me to fix but i will let it go cheap

MW3 · Post by **MW3** » Fri Feb 10, 2012 9:23 am

Interesting amplifier. Has two transformers yet power supply/output stage seems to only dictate one.

I never cared for a Picasso, it was gutless. Nice amp for listening at low levels in an IASCA car back in the day.

But that's no fun. Headroom is where its at.

What are the output devices?

longboard · Post by **longboard** » Fri Feb 10, 2012 9:36 am

ive got a focal dual monitor here and a fp 800.1

there great amps the dual monitor we used when competeing in iasca on a set of k3 power speakers sounded great im going to use it on a set of ti elites in the lexi

itchnertamatoa · Post by **itchnertamatoa** » Fri Feb 10, 2012 3:35 pm

Eric D wrote:A I no longer have that Picasso

that would be my fault ....

Post by **kg1961** » Fri Feb 10, 2012 3:38 pm

ha ha its my fault he loves the focal
what can you do

Post by **Eric D** » Fri Feb 10, 2012 6:09 pm

Morgan, the Focal has dual transformers, but only one pair of rectifier diodes (each with two diodes in one package), so it is just a single power supply.

The outputs are TIP35C and TIP36C I am pretty sure.

I think I need to pop it open and snap some photos for people to see.

Post by **kg1961** » Fri Feb 10, 2012 6:35 pm

i would love to see the repair eric
i just deleted the photo i sent you yesterday

Post by **ttocs** » Fri Feb 10, 2012 6:43 pm

sounds like you had one of those OMG audio moments? I can remember having a similar moment when our sales rep dropped off the new diamond hex componants for us to demo back in 94-95. To that point ID was our gold-standard for SQ and I remember sitting there lookin at the diamond tweet held on with tape to our sound board and being just amazed at the difference in the a-b comparison....

shawn k · Post by **shawn k** » Fri Feb 10, 2012 7:19 pm

Have to give Focal credit. When they finally released some amplifiers.... they did it right! Good stuff!

00goobs · Post by **00goobs** » Fri Feb 10, 2012 8:37 pm

Soooo, would one think there is a voodoo enhancement somewhere in the frequency range? Maybe the midrange? I wonder if using a dual channel o-scope would reveal differences in the output at certain frequencies between 2 amps receiving the same signal?

I think I've heard a difference between my older ZXTi amps and M series in the midrange. I would like to know if there is a way to see the difference using an o-scope....

Post by **Eric D** » Sat Feb 11, 2012 7:29 am

I highly doubt something is different related to frequency response. I am still thinking it has to do with lots of feedback, and lots of control over the speaker.

Post by **kg1961** » Sat Feb 11, 2012 5:52 pm

very very odd i wish i new more about how amps work

neverman · Post by **neverman** » Tue Feb 14, 2012 1:34 am

ttocs wrote:sounds like you had one of those OMG audio moments? I can remember having a similar moment when our sales rep dropped off the new diamond hex componants for us to demo back in 94-95. To that point ID was our gold-standard for SQ and I remember sitting there lookin at the diamond tweet held on with tape to our sound board and being just amazed at the difference in the a-b comparison....

I'm still loving on my Diamonds, I've worked very hard over the last, almost TWENTY flippin years, to keep this set running. I've replaced a driver and a silk dome over the years and both x-overs... It's getting hard to think I'll have to give them up when something new "bad" happens. Eton did me right! I do remember that 1st time in the showroom when I heard them and was totally blown away. I'm sure I could do better somehow now but I'm so used to that sweet smooth effortless music.

STROKD · Post by **STROKD** » Fri Feb 17, 2012 4:33 am

Eric, Ive heard the Focal amps as well and think they sounded great...

Have you ever tested an Audison VRx or their new Thesis lineup (replaced the VRx_ not the amp called The Thesis)...

The VRx is the best damn amp Ive ever heard, but I was wondering what it sounded like compared to the Focal/Zapco/Picasso you liked so much.

lowblueranger · Post by **lowblueranger** » Sun Feb 19, 2012 1:45 pm

I might be interested in the amplifier,pm sent.

Post by **kg1961** » Sun Feb 19, 2012 2:46 pm

please send the pm to eric ha owns the amp now

Post by **Eric D** » Sun Feb 19, 2012 4:23 pm

STROKD wrote:Eric, Ive heard the Focal amps as well and think they sounded great...

Have you ever tested an Audison VRx or their new Thesis lineup (replaced the VRx_ not the amp called The Thesis)...

The VRx is the best damn amp Ive ever heard, but I was wondering what it sounded like compared to the Focal/Zapco/Picasso you liked so much.

I have never even seen an Audison amp in person. I would love to try one.

I also have not seen a Sinfoni, and would like to try one as well.

Post by **smgreen20** » Sun Feb 19, 2012 9:49 pm

I know this isn't IN PERSON, but here are some pics of my own Audison LRx5.1k

shawn k · Post by **shawn k** » Mon Feb 20, 2012 6:46 am

My VRX4 300.2 I ran for a while.

Sexy