MAT02, 03 Elektor preamp schematic

[Samuel Jayaraj]

jacco,

Sorry that I did not read your post careful enough. How do you compare the sound of the opamp vs. discrete preamps? both hi-end ofcourse, but the sound?

resolution,

Thanks for that schematic. Yes that was the simplest one I was after because I want to check this vs. the one with the servo.

peranders,

Thanks for the update on availability. I will contact AD in India to get the MAT03s; I already have about 8 Nos. of MAT02s.

[peranders]

Originally posted by Samuel Jayaraj
Thanks for the update on availability. I will contact AD in India to get the MAT03s; I already have about 8 Nos. of MAT02s.

Notice though that SSM2210, 2220 are much cheaper and the same transistors.

[Elso Kwak]

Originally posted by peranders
Notice though that SSM2210, 2220 are much cheaper and the same transistors.

This is simply not true. Yes the datasheet claims the same specs but when I measured MAT02s and SSM2210s the former had much higher hFE. Also I noticed different sound.
See also:
http://www.diyaudio.com/forums/showt...189#post492189

[jacco vermeulen]

Originally posted by Samuel Jayaraj
How do you compare the sound of the opamp vs. discrete preamps?

Just build the circuit, you will not be dissapointed.
In my opinion Elektor made a very elegant design, with an attractive pricetag.

550C/560C are still my fav. small signal transistors.
Great specs, their low price makes them tops for selecting/matching.I still have 100s of them.
Types with lower noise ratings are way more expensive.

I think elektor made a number of poor designs.
Their Hitachi Mosfet Crescendo was built by the thousands,not a great amp in my view, the design loved to swing the wrong way.
I built the discrete preamp that was designed at the time of the 1st edition Crescendo's, and it was total crap.
As the designs were meant for DIY purposes Elektor took the path to designing circuits that were DIY foolproof for quite some time, stuffed with Miller,Lead,Lag compensation.
Elektor later designed circuits that were too difficult for most of their readers, their IGBT power amplifier was not a succes , i gathered, Mark Alexander's IGBT design just moderately.

I built an elektor poweramp with entrance SSM22**'s, at the time i gathered that the SSM used the lower end MAT's, beside the low cost package. Maybe that has changed, MAT0*'s still cost at least twice as much though.

I built this design because i liked it.
For a line stage you can probably use the SSM's if they differ a little from the regular MAT's, otherwise the circuit is even cheaper to build.
The offset servo gives you next to none DC, i love the sight of Leds and they produce far less noise than regular diodes.
Besides being subjective i am not going to state which is best, this circuit outperforms the initial double OP27 integrated circuit from elektor and it costs less.
Comparing it with the OPA627 is not fair moneywise, the lowest i know of abroad is like $20 each, the shop here around the corner sells it for $47.
Personally i rave about the OPA627/637, on another thread i just posted on how i even used a bunch of them in my 8 channel car amps.
Unlike the OP27 the OPA627 has been specifically designed for audio applications.
The japanese industry has been designing state of the art audio transistors for a long time, i am paying at most 1/5 th for Sanken's 1216 (and Toshiba's 5200) now that they have become more common compared to 15/20 ago, the Sanken's i regard as brilliant audio power transistors.
In my view the chip industry still has not reached the end level in integrated audio circuits.
Nelson Pass lately stated that some prefer white, some red.
I like the Burr Brown sound, even if it is integrated.

I agree with you that elektor's discrete design is not just another electronic mag circuit, it sounded wonderfull hooked up on several class A power amps with full power bias in 8 ohms and ESL's.

[jacco vermeulen]

Originally posted by Elso Kwak
Also I noticed different sound.

Nice thread, Elso.
A lot of the details in your KISS layout underscribe my findings.
e.g. : as i have the skills and possibilities of constructing steel casings i see no point in alloy case building, mine are 1/3 " plate minimum with threaded holes for hardened/chromed hex bolts.

Is it possible to give some specific details on the toroid choke cores you mentioned ?

I am asking because i am building a large number of Pass amps for an active system, currently thinking of adding two Zen XA's, for which i want choke regulation.
In 2005 i want to have a go at Pass's monster, for that i just hauled two 5000VA toroids in my garage.

The Amazon lines sounded nice, but remind me a tadd of Gregory Peck in Paraguay. You have twins ?

Wacko.

[Nexus]

Hello Resolution,

do you have a pcb layout of the UFOA.PDF schematic from post#17?

Best Regards:
Nexus

[arasuk]

Hi !!!

I Just build the circuit & tested this preamp, finding its quality Appreciation in this Thread.
I am having some problems, This preamp is giving out DC ?ve10.23 volts, I have checked no shorts, I have Used Bc 550/560c Instead of MAT 02/03, due to the non availability of original matched transistors.

Hope guys here will help me.

Thanks
Arasuk

[resolution]

Hi Nexus,

Sorry about the delay getting back to you.

As it happens I do. I use Pads PCB. I can email the file to you as is, or compile it into a multi-page pdf. It is a double layer with top ground plane.

I've included a 3 page pdf for your perusal.
P1. Schematic
P2. Top
P3. Bottom

All PCB layouts are 2:1 un-mirrored

If you need all the PCB details in pdf or CAM photo then can you give me a few of days - it my wife's birthday the day after tomorrow and things are just a bit manic right now with that and work.

Let me know what you require.

Kind regards

res

[Nexus]

Hello Resolution,

yes, I am interested in the PDF variant, I do not use PADS.

But pdf is fine, you can use my email if you wish.

Thank You in advance.
Nexus

[Bgt]

Jacco,
I've built many crescendo's on my own PCB's and they're the best. I also have the Rotel RC990/RB980 combination+NAD 162/272, but they are not as good as the Crescendo.
Go figure. I use a homemade passive with the Crescendo's and they are way better than the commercial units.
Its a matter of opinion. I use them with Driade's boxes.