Just wondered what people thought of this amp, I have built on once but broke it and never got to listen to it. They are cheap and are good quality but are they that good?
Velleman nv
I belive this is the schematic:
Boscoe
Velleman nv
I belive this is the schematic:
Boscoe
Not really , no current sources , low PSRR. Darlington OPS shunted by 680pF ... questionable stability. A similar amp with a current source and a true 2 stage emitter follower output scheme would be miles ahead in durability and sound quality. (below) is a similar but much more refined amp , it's sonics would overwhelm the velleman by a VERY wide margin at the cost of 3-4 more devices (cheap). The Velleman is more of a "student" amp , not really Hi-Fi 😱 .
OS
OS
Attachments
It's a typical low cost kit amp, using cheap darlington outputs. It'll work - thats about the best you can say about it.
The person in that thread was trying to run the amp from higher supply voltages. on 35V supplies (using a 2x25v transformer) this circuit is OK - this is typical supply voltage, while Velleman show 40V supplies this would be the unloaded voltage, and will soon sag under load.
I run a pair of TIP142/147 all day long, with +/-38 to +/-40V supplies, into 4 ohms with no problems whatsoever.
Mind you, they are Guitar/Bass/PA amps, which get a beating.
Yes, supply voltages sag a lot under heavy load.
Mind you, they are Guitar/Bass/PA amps, which get a beating.
Yes, supply voltages sag a lot under heavy load.
Good amplifier
I have built this amplifier, and it works well, no problem with stability or distortion.
I have built this amplifier, and it works well, no problem with stability or distortion.
Hi ! very interesting minimalist amp
May i ask about its sound ? what are you using as preamp ?
Thanks and regards,
gino
the sound of transistors that DO NOT provide their audio specs can and will be horrible
Then again you will never be able to source and reliable TIP 142-147 and the circuit suffers from a number of problems
It will stand a chance with far lower rails but still its a ticking bomb All kits produced on the above circuit and even more sophisticated with VI limiters eventually find their way to the creator
Keep away!!!! When small (60Watt ) powerful, plenty of kick, surprisingly clean sound ? check Dx amplifier or a P3A at this ratio of part count you will find nothing better in class AB add to that all parts available and loads of support !!!
Kind regards
Sakis
Then again you will never be able to source and reliable TIP 142-147 and the circuit suffers from a number of problems
It will stand a chance with far lower rails but still its a ticking bomb All kits produced on the above circuit and even more sophisticated with VI limiters eventually find their way to the creator
Keep away!!!! When small (60Watt ) powerful, plenty of kick, surprisingly clean sound ? check Dx amplifier or a P3A at this ratio of part count you will find nothing better in class AB add to that all parts available and loads of support !!!
Kind regards
Sakis
it's also so strange connected , those tips, i bought one, but stopped assembling halfway, since it never can be a great sound and 100 watt rms??... Just take a tda 1794 with toshiba's 5200 and 1492 and Build a psu with quite some caps 4700uF. or maybe larger and a decent torrodial. With a nice large coolblock and decent components and some filtering on the inputcaps( Psu) and you'll probably wil need two torrodial psu's sym lower votage for 1492 and higher voltage for the 5200 and 1492... It can sound good, even on a testboard, but it wont be the most bbeautifull build ever seen...
Hi just a curiosity.
The " voltages sagging " should not be the consequence of an undersized power supply ?
However ... i am still trying to understand if this design is stable or not.
Me too i do not like the pcb at all ...
i cannot understand this mania of small pcbs ... okkey ... they are cheaper.
Thanks, gino
- Status
- Not open for further replies.