Audio Power Amplifier by Douglas Self

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Member
Joined 2014
Paid Member
It's easy to replicate modern concert sound in your house: Just dial volume to ten and it will be as unintelligible as most concert sound is - WAY TOO LOUD, lots of room reflections to reduce clarity - just total crap - instant hearing damage - won't matter if the amp is clipping or not.


You obviously go to different concerts than I do. I'm old fashioned and use real live acoustic performances as my reference, rightly or wrongly.
 
Hi billsbury

Any amplified concert I've been to since 85 has been way too loud and it does not matter the music type.

Most modern instruments are designed to be loud so a large gathering of people can hear. Wind instruments particularly are next to impossible to play quietly. Violins can be piercing depending on who's playing and how well setup the instrument is. Acoustic guitars got metal strings so they could be louder. Even a piano can be kind of loud depending on the player and the piano. Surprisingly, old-style drums can be played fairly quietly but modern drums with hydraulic heads are abysmal tonally and lack any good dynamic output, so get bashed a lot.

Personally, I don't need to hear any of these things as loud as they are in real life in my living room. When I was young and foolish I cranked up the stereo but soon realised it did not sound as good and had a bad physiological effect. Now I'm old and foolish and listen to things quieter.
 
The Rectron is about 5x the Nexperia capacitance - chip layout and process differences.

But if your design is ok with the 2.5pF, it should be ok.

Once you are above a few volts Vr, the change in capacitance if quite flat anyway in the big scheme of things.


Is there anything better out there ??

What I have is a diode that needs to conduct forward at 1/3 of the cycle , but quickly
goes reverse to as much as -80V reverse for the other 2/3rd.
https://www.fagorelectronica.com/im...des-for-High-Speed-Switching-Applications.pdf


Have you tried any "ultra soft recovery" high speed diodes ? The reverse recovery seems to be the performance variable for both the high power
schottkey and ultrafast diodes when used in a class H application.

This "recovery" can easily be seen even in simulation.

OS
 
Unintelligible at high volume ??
A 200W class D 12" sub + 2 LM3886's for >100hz , I can go at least 2/3rd's volume
@ 110db and the clarity is phenomenal.
A little too loud right at the HF monitors , but nice at the other end of the room.
Over 2/3 volume , cans and windows "buzz" detracting from the hi-fi. Had to
caulk some glass on the older windows and doors.
Had to just put cans separated in the cupboard behind the sub , the glass canning
jars "chimed" too loud.
I only go loud for some songs that "demand it" . I like to carry conversations
(without shouting) while listening.

OS
 
It's easy to replicate modern concert sound in your house: Just dial volume to ten and it will be as unintelligible as most concert sound is - WAY TOO LOUD, lots of room reflections to reduce clarity - just total crap - instant hearing damage - won't matter if the amp is clipping or not.
I think David's friend is more like Alfred Brendel trashing the Bosendorfer at ANU :)

If Alfred came to my shed in Cooktown, I would be asking Theme & Variations nicely if they could just ship up a Steinway for his pleasure.

I would expect the recording (TetraMic but no 788 :() to leave me very dissatisfied that I don't have the 1000W or even a 200W anymore and perhaps take up astx's offer :eek:

On the other hand, I've pointed out there is modern music (?) where clipping 50% of the time is undetectable .. let alone objectionable. :cool:
 
Member
Joined 2011
Paid Member
If you don't mind a 20V max reverse bias constraing, these are pretty low. Otherwise perhaps the 1N916B

_
 

Attachments

  • Image1.png
    Image1.png
    463.1 KB · Views: 237
That is SMD and in DIY not everybody is ready to use it. Is there any THT diode with similar low capacitance?


Why , the larger packages (D-pac ,SOT223 , 10mm smd resistors) are as
large as through-hole.
No flipping boards over or clipping leads. Those 1/8w smallest resistors are
way worse to apply than some SMD.

A hybrid , like the Holton amps , are advantageous.
The only components I don't like are the 363 tiny dual transistors and the
smallest smd resistors.I don't like the SOP 8-pin IC's for my servo ,
but they are just .$40c , I could fit the whole servo circuit just where
the DIP would go.

Soon , there will be almost no choice for through-hole. Many on Mouser
are tagged "obsolete" .. with just remaining stock.


OS
 
Why , the larger packages (D-pac ,SOT223 , 10mm smd resistors) are as
large as through-hole.
No flipping boards over or clipping leads. Those 1/8w smallest resistors are
way worse to apply than some SMD.

A hybrid , like the Holton amps , are advantageous.
The only components I don't like are the 363 tiny dual transistors and the
smallest smd resistors.I don't like the SOP 8-pin IC's for my servo ,
but they are just .$40c , I could fit the whole servo circuit just where
the DIP would go.

Soon , there will be almost no choice for through-hole. Many on Mouser
are tagged "obsolete" .. with just remaining stock.


OS

I am prepare myself to start soon some SMD, probably small preamp first.
Still I don't see any SMD replacement for video transistor like 2sa1381/2sc3503, with very low Cob. Any suggestions?
 
www.hifisonix.com
Joined 2003
Paid Member
I've gone 'mixed assembly' - SMD parts are easy to mount and you can build compact boards with them. I still use leaded for critical parts (like FB resistors or resistors and that have high voltages/powers across them).

There's some fantastic 0805 and 1206 NPO/COG caps available now - not may film caps can compete and you can get them at 500 - 1kV ratings. mouser has a good range.
 
Member
Joined 2014
Paid Member
Hi billsbury

Any amplified concert I've been to since 85 has been way too loud and it does not matter the music type.


I did say acoustic. Reproducing megadeth concerts at home is not my idea of fun.


Most modern instruments are designed to be loud so a large gathering of people can hear. Wind instruments particularly are next to impossible to play quietly. Violins can be piercing depending on who's playing and how well setup the instrument is. Acoustic guitars got metal strings so they could be louder. Even a piano can be kind of loud depending on the player and the piano. Surprisingly, old-style drums can be played fairly quietly but modern drums with hydraulic heads are abysmal tonally and lack any good dynamic output, so get bashed a lot.

Personally, I don't need to hear any of these things as loud as they are in real life in my living room. When I was young and foolish I cranked up the stereo but soon realised it did not sound as good and had a bad physiological effect. Now I'm old and foolish and listen to things quieter.


Like the late, great Peter Baxandall I prefer to sit further back in the hall where the average levels are much lower and very similar to those of normal listening levels at home. At the Royal opera house I pick the balcony so i get a direct line of site to the orchestra pit.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.