NXP Webinar May 2025 (728x90)
Become a Member
elektor
elektor
Members Only​
Article

Crescendo Millenium Edition

remake of a famous amplifier

Crescendo Millenium Edition
Crescendo Millenium Edition
In early 1984, Elektor magazine beat the competition hands-down by publishing the design of a then-revolutionary MOSFET amplifier. Even now, this amplifier enjoys an enthusiastic following. In response to many requests, we have brought the design up to date and given some attention to improved reliability and operating safety. The output power is 90 watts into 8 ohms or 135 watts into 4 ohms, which should leave little to be desired for most users.There are surely not very many circuit designs that continue to enjoy such a high level of interest more than ten years after their original appearance, as does the Crescendo power amplifier from 1984. In part, this is due to its completely symmetrical design, which was in fact an unusual feature at that time, but unquestionably it is mainly due to the use of power MOSFETs in the output stage. A lot of people happen to be fervent fans of these devices. Even people who swear by valve amplifiers and are allergic to anything with ‘semiconductor’ in its name often have a weakness for MOSFETs, and are thus prepared to make an exception for them. Sadly enough, most of the problems with the amplifier in question had to do with the MOSFETs.
Log in here as a subscriber to read the article.

This is a MEMBER ONLY article. You need a subscription to read this article.

Benefits of a subscription
  • Unlimited access to online Member Only articles
  • 3 new editions Elektor Magazine (digital)
  • More than 5000 Gerber files
  • 20% member discount on e-books (at elektor.com)
  • 10% member discount on Products (at elektor.com)
View the offers
Available from €5.33 per month.
What is Elektor Exclusive?

Materials

Gerber file

CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor GREEN and GOLD members can exclusively download these files for free as part of their membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service.

Elektor recommends the Elektor PCB Service service from its business partner Eurocircuits or AISLER as the best services for its own prototypes and volume production.

The use of our Gerber files is provided under a modified Creative Commons license. Creative Commons offers authors, scientists, educators and other creatives the freedom to handle their copyright in a more free way without losing their ownership.

PCB

Component list

Amplifier board
Resistors:
R1 = 1MOhm
R2 = 47kOhm
R3,R22 = 470Ohm
R4,R5 = 1MOhm 8
R6,R7,R11,R12 = 47Ohm
R8,R9,R13,R14 = 1kOhm
R10,R15 = 330Ohm
R16,R19,R30,R31 = 22kOhm
R17,R20,R28 = 270Ohm
R18,R21 = 8kOhm 2
R23 = 12kOhm
R24,R26 = 10kOhm
R25,R27 = 33Ohm
R29 = 120Ohm
R32,R33 = 220Ohm
R34,R35 = 0Ohm 22 / 5W low-inductance, e.g., MPC71 series
R36 = 10Ohm / 1W *
R37 = 1Ohm / 5W
P1 = 1kOhm preset H
Capacitors:
C1 = 2µF2, MKT (Siemens), lead pitch 5mm or 7.5mm
C2,C4,C5 = 1nF
C3 = 180nF
C6,C7 = 100µF 25V radial
C8,C9 = 220µF 25V radial
C10,C12,C14 = 100nF
C11 = 10nF *
C13,C15 = 1000µF 63V radial
Inductors:
L1 = 9 turns 1.5 mm dia. ECW around R37, inside diameter 8 mm
Semiconductors:
D1,D2 = rectangular face, red
D3,D4 = zener diode 3V9 / 0.5W
T1,T2,T6 = BC546B
T3,T4,T5 = BC556B
T7 = BC560C
T8 = MJE350
T9 = BC550C
T10 = MJE340
T11 = 2SK537 (Toshiba)
T12 = 2SK1530 (Toshiba)
T13 = 2SJ201 (Toshiba)
Miscellaneous:
5 off M3 spade terminals, PCB mount
3 off ceramic (or mica) isolating washer for voor T8/T10/T11
2 off mica isolating washer for T12/T13 (e.g., TO-218 sheets size 21 x 24 mm)
Heatsink: <0.5° K/W (e.g., Fischer type SK47/100 mm, Dau Components)
PCB, ord3r code 010001-1
Mainsd power-on delay PCB , order code 974078-1
Enclosre, e.g., Monacor (Monarch) type UC113/SW
*) may be omitted
Protection board
Resistors:
R1,R4 = 390Ohm
R2,R5 = 120Ohm
R3,R6 = 18kOhm
R7,R9 = 1kOhm / 5W
R8,R10 = 5kOhm 6
R11,R25,R30,R31 = 10kOhm
R12,R13,R24 = 1MOhm
R14 = 150kOhm
R15 = 39kOhm
R16,R20,R21 = 220kOhm
R17 = 330kOhm
R18 = 12kOhm
R19 = 330Ohm
R22 = 15kOhm
R23 = 680Ohm
R26,R27 = 4kOhm 7
R28 = 470kOhm
R29 = 3kOhm 3
Capacitors:
C1,C2 = 150pF
C3,C4 = 22µF 63V radial
C5 = 47µF 63V radial
C6 = 2µF2 MKT (Siemens), lead pitch 5mm or 7.5mm
C7,C8

Discussion (0 comments)

elektor

sercan 2 years ago

can it work good with new components instead old?
2sk537=IRFBF20
2SK1530=ECW20N20
2SJ201=ECW20P20
BC550C=BC850C
BC860C=BC860C


cs.png (83kb)
Reply
elektor

Brian Tristam Williams 2 years ago

See Ton's comments from below: "Never replace original components with alternatives. Even if if properties are close to the original, this can have unforeseen consequences like instabilities and oscillations. Sadly no exact replacements are known. The 2SK537 was used for its thermal properties, not the high voltage specification."

Thanks!
Reply
elektor

Fabrício S Taveira 1 year ago

Yes, no problem!
Reply
Show more
1 Attachment(s) 2 Comment(s)
elektor

TonGiesberts 2 years ago

Never replace original components with alternatives. Even if if properties are close to the original, this can have unforeseen consequences like instabilities and oscillations. Sadly no exact replacements are known. The 2SK537 was used for its thermal properties, not the high voltage specification.
Reply
elektor

sercan 2 years ago

thank Ton;
I am going to do your new project that 's been Fortissimo amp. But Really I am like to listen to mosfet sound. Do you have or know  any project with mosfet amplifier on elector?
Reply
elektor

TonGiesberts 2 years ago

Sorry, no MOSFET amplifier is planned at this moment. I hope you'll like the Fortissimo-100 amplifier. 
Reply
elektor

sercan 2 years ago

dear Ton Fortissimo is like a diamond for me. thank you.
Reply
Show more
1 Comment(s)
elektor

Laszlo Takacsy 1 year ago

I wonder if you can advice how to get the pcbs manufactured with a recommended service company, without subscribing the magazine itself. Is there someone outhere who has the gerber data and sepcialized in producing these pcbs? I downloaded the data as suggested above, but the files are in an anknown format, I guess they are protected.  Or I need to subscribe in order to get the Gerber files?  
Reply
elektor

TonGiesberts 1 year ago

You need to have an account to download the gerber files. A subscription is not needed
Reply
Show more
1 Comment(s)

Embed Code