Precision Matched Vishay IRFP240 IRFP9240 MOSFETs and IRFP240 MOSFETs
- By rhthatcher
- Swap Meet
- 51 Replies
Attachments
An arguably better replacement for the resistor in a CRC power supply - R21 PS module
- By tombo56
- Power Supplies
- 341 Replies
R21 is power supply add-on module that replaces resistor between two capacitors in a standard CRC power supply and transforms it in to the regulated power supply. It has high PSRR and output current, low dropout voltage, output impedance, and noise. Transient response is good and module dimensions are small.
It works, as is without any changes, from 10 to 65 V output voltage and load up to 10 A, with dropout voltage of 0.15 V for 10 A load, PSRR greater than 100 dB @ 100/120 Hz and total noise less than 3 uV. Headroom voltage is 0.5V for 10 A load.
Single rail module dimensions, including heatsink, are 70 x 60 x 38 mm.
Why I made and published this is explained here:
https://www.diyaudio.com/forums/pass-labs/376002-amplifier-extension-power-supply.html#post6759478
As I see it, the most favorable property of this regulator module is that it can be used as an upgrade on wide variety of existing power supplies and that it can be easily utilized on one DIY project and then repurposed for another one. With this add-on regulator, single power supply is upgraded to the level above dual mono PS configuration.
Measured performance:
That's all fine, but there is a catch.
You can't use regulator at 0.3 V voltage drop in the ordinary CRC power supply, as there is a substantial ripple voltage at the first capacitor in the CRC line and there is also some mains voltage variation. In example, usual 30 mF capacity will provide 1 Vpp ripple at 3 A load. Minimum drop that can be used is half the ripple voltage + min. regulator headroom: 0.5 + 0.3 = 0.8 V. Add some headroom for the mains fluctuation/voltage drop at load and, realistically, 1.5 - 2 V drop is what can be used as a minimum on A class power amplifiers.
There was some voltage drop on the resistor in the CRC chain, so only 1.5 V is lost. That shouldn't be a problem, but if you really need every volt, then replace diode rectifier bridge with active rectifier (LT4320). This will provide 1.5 V higher rectified voltage in comparison to diode bridge.
For the new designs, you can order transformer with 2 V higher secondary voltage.
Building
Complete documentation including BOM, one click shopping cart, gerbers and build guide is attached. I've made a reasonable effort to provide documentation that will be sufficient for anyone to build this module, however this project is not suitable for beginners. Design is made with through hole components, as much as possible. There are only two really easy to solder SMD components that require fine soldering tip.
Parts
Recent parts shortages postponed project for 8 months. At any moment, something from the parts list was not available. I had to find and verify suitable replacements. Situation is increasingly frustrating and it is hard to obtain all parts from only one source or at all. I've prepared one click Mouser shopping carts for easy ordering, though you'll certainly need to adjust them.
Mouser Electronics, Inc. Croatia
It works, as is without any changes, from 10 to 65 V output voltage and load up to 10 A, with dropout voltage of 0.15 V for 10 A load, PSRR greater than 100 dB @ 100/120 Hz and total noise less than 3 uV. Headroom voltage is 0.5V for 10 A load.
Single rail module dimensions, including heatsink, are 70 x 60 x 38 mm.
Why I made and published this is explained here:
https://www.diyaudio.com/forums/pass-labs/376002-amplifier-extension-power-supply.html#post6759478
As I see it, the most favorable property of this regulator module is that it can be used as an upgrade on wide variety of existing power supplies and that it can be easily utilized on one DIY project and then repurposed for another one. With this add-on regulator, single power supply is upgraded to the level above dual mono PS configuration.
Measured performance:
- 104 dB PSRR @ 100/120 Hz at 0.3 V headroom and 5 A load
- 2.5 uV total noise @ 5 A DC load or 17 nV/rtHz noise density @ 1 kHz
- 0.01 % load regulation @ delta I = 9.3 A (2 mV output voltage change for the 9.3 A load increase at 30 V output)
- 0.001 %/V line regulation @ delta V = 10 V (1 mV output voltage change for the 10 V input voltage rise)
- 40 uOhm output impedance @ 20 kHz
That's all fine, but there is a catch.
You can't use regulator at 0.3 V voltage drop in the ordinary CRC power supply, as there is a substantial ripple voltage at the first capacitor in the CRC line and there is also some mains voltage variation. In example, usual 30 mF capacity will provide 1 Vpp ripple at 3 A load. Minimum drop that can be used is half the ripple voltage + min. regulator headroom: 0.5 + 0.3 = 0.8 V. Add some headroom for the mains fluctuation/voltage drop at load and, realistically, 1.5 - 2 V drop is what can be used as a minimum on A class power amplifiers.
There was some voltage drop on the resistor in the CRC chain, so only 1.5 V is lost. That shouldn't be a problem, but if you really need every volt, then replace diode rectifier bridge with active rectifier (LT4320). This will provide 1.5 V higher rectified voltage in comparison to diode bridge.
For the new designs, you can order transformer with 2 V higher secondary voltage.
Building
Complete documentation including BOM, one click shopping cart, gerbers and build guide is attached. I've made a reasonable effort to provide documentation that will be sufficient for anyone to build this module, however this project is not suitable for beginners. Design is made with through hole components, as much as possible. There are only two really easy to solder SMD components that require fine soldering tip.
Parts
Recent parts shortages postponed project for 8 months. At any moment, something from the parts list was not available. I had to find and verify suitable replacements. Situation is increasingly frustrating and it is hard to obtain all parts from only one source or at all. I've prepared one click Mouser shopping carts for easy ordering, though you'll certainly need to adjust them.
Mouser Electronics, Inc. Croatia
Attachments
Audio Board - Asus - REW
- By jeffrowland
- Equipment & Tools
- 5 Replies
I ran some tests with REW while waiting for the Scarlet 2i2 3rd.
On the Asus motherboard there is a 5.1 that I use in 2.1 (4front/modified) and on the subwoofer there is a 5" Vifa.
Here is the measurement of the card with this configuration.
How do you think?
On the Asus motherboard there is a 5.1 that I use in 2.1 (4front/modified) and on the subwoofer there is a 5" Vifa.
Here is the measurement of the card with this configuration.
How do you think?
Remove tweeter from cabinet
- Construction Tips
- 14 Replies
Would anyone be able to provide some suggestions for removing a tweeter from a cabinet. I don’t have any experience fixing speakers, but thought I tried. I have an old Fischer and Fischer 1000 built in 2000 that I am restoring. I’m trying to remove a damaged tweeter. The outer plate seems glued-in, but why would someone do that? The bass drivers are not glued-in and were removed easily. I don’t want to exert too much force as to not damage the aluminum plate. Things I tried:
1. I used a heat gun to loosen any glue, but I don’t think I got it hot enough I was afraid of using too much heat.
2. Prying/pulling: I exerted more force than I thought should be necessary, but I stopped due to fear of damaging the outer plate.
Any thoughts would be appreciated.
1. I used a heat gun to loosen any glue, but I don’t think I got it hot enough I was afraid of using too much heat.
2. Prying/pulling: I exerted more force than I thought should be necessary, but I stopped due to fear of damaging the outer plate.
Any thoughts would be appreciated.
opinions
- By bikerjay
- Electronic Design
- 5 Replies
I got my speakers built today. I just need to figure out the crossovers. I'm attempting a 2.5 way (as I understand it) since it is a MTM. I'm still not 100% on any of it really but what phase should look like on a graph is what I'm least sure of. Phase is represented by the thin line. I'm confident that its not perfect but it's not bad either
Attachments
For Sale PCB set for Douglas Self Preamplifier
- By Wolfman1969
- Swap Meet
- 14 Replies
Complete PCB SET for Douglas Self Preamplifier from Elektor [april. may, jun 1012}.
7 PCBs + all 3 ELEKTOR issues in PDF format about building the preamplifier
costs 70$ + shipping
7 PCBs + all 3 ELEKTOR issues in PDF format about building the preamplifier
costs 70$ + shipping
Rescuing & Reimagining a Technics SL-100c
- By mcrushing
- Analogue Source
- 95 Replies
Dissected, but far from dead:
Here lies the nerve center of an essentially brand-new Technics SL-100c:
So... Where to begin?
Browsing eBay on a recent evening, I ran across a listing to the effect of, " !!PARTS!! Technics SL-100/1500 Tonearm, Platter, Motherboard, Otherboard. "
Okay, uhhh... [clicks mouse]
As advertised, the seller was parting out a "damaged in shipping" 100c that he'd purchased "as a return." After some back-and-forth, a story emerged: Apparently someone bought this $1k+ turntable on Amazon, stripped off the stock cartridge and then returned it in the original box (minus most of the original engineered packaging). As many likely know, there's sort-of a supply chain purgatory where (literally) billions of returned items languish for long periods before being either bundled and resold or trucked off to a landfill. Never did I imagine those items to include things like brand-new turntables with ultra-accurate coreless motors that hifi mags have been raving about.
According to the seller, the unit was basically loose in the box and took a beating in transit: Dustcover destroyed, tonearm badly damaged, chassis cosmetically irredeemable, and... motor working perfectly. Unable to stop myself, I bought the motor, platter and everything you see here for a few hundred bucks.
Why tho?
Well for one thing, I've since confirmed the performance: Assembled with the motor just sitting on my desk, the RPM iphone app shows the platter running at 33.34 +0.03, w/f 0.15% (and even better at 45). That DUSTS the belt-drive deck I spent a mint on five years ago (which frankly leaves me wanting in other ways as well). More than anything, I just want to get my hands into this. I lust after classic broadcast decks, and have long wanted to join the SP-10 club (yes, I've spent a lot of time on The Incredible Thread). But for a lower price-of-entry, and given the specs above, this seems like a pretty cool alternative challenge.
And before anyone asks: Yes, I'm a bit out of my depth. I know this will cost more than I think. I don't yet have all the tools I'll need. There will be massive research and a lot of trial and error. I know there's a lot I don't know, and I'm prepared for this to take a long time.
So all that said, this thread will serve as the build log.
It's getting late, but at some point over the weekend I'll post my progress so far, my overall plan, anticipated next steps, and a few questions for the forum.
Really hoping a few of Technics Heads (and other experienced folks) will vibe with this project, follow and advise.
Cheers!
Here lies the nerve center of an essentially brand-new Technics SL-100c:
So... Where to begin?
Browsing eBay on a recent evening, I ran across a listing to the effect of, " !!PARTS!! Technics SL-100/1500 Tonearm, Platter, Motherboard, Otherboard. "
Okay, uhhh... [clicks mouse]
As advertised, the seller was parting out a "damaged in shipping" 100c that he'd purchased "as a return." After some back-and-forth, a story emerged: Apparently someone bought this $1k+ turntable on Amazon, stripped off the stock cartridge and then returned it in the original box (minus most of the original engineered packaging). As many likely know, there's sort-of a supply chain purgatory where (literally) billions of returned items languish for long periods before being either bundled and resold or trucked off to a landfill. Never did I imagine those items to include things like brand-new turntables with ultra-accurate coreless motors that hifi mags have been raving about.
According to the seller, the unit was basically loose in the box and took a beating in transit: Dustcover destroyed, tonearm badly damaged, chassis cosmetically irredeemable, and... motor working perfectly. Unable to stop myself, I bought the motor, platter and everything you see here for a few hundred bucks.
Why tho?
Well for one thing, I've since confirmed the performance: Assembled with the motor just sitting on my desk, the RPM iphone app shows the platter running at 33.34 +0.03, w/f 0.15% (and even better at 45). That DUSTS the belt-drive deck I spent a mint on five years ago (which frankly leaves me wanting in other ways as well). More than anything, I just want to get my hands into this. I lust after classic broadcast decks, and have long wanted to join the SP-10 club (yes, I've spent a lot of time on The Incredible Thread). But for a lower price-of-entry, and given the specs above, this seems like a pretty cool alternative challenge.
And before anyone asks: Yes, I'm a bit out of my depth. I know this will cost more than I think. I don't yet have all the tools I'll need. There will be massive research and a lot of trial and error. I know there's a lot I don't know, and I'm prepared for this to take a long time.
So all that said, this thread will serve as the build log.
It's getting late, but at some point over the weekend I'll post my progress so far, my overall plan, anticipated next steps, and a few questions for the forum.
Really hoping a few of Technics Heads (and other experienced folks) will vibe with this project, follow and advise.
Cheers!
Amplifier with Predictable Output Impedance
- By Jontie
- Solid State
- 14 Replies
I'd like to present a design for a power amplifier, the main features of which are as follows:
The principle on which the design is based is that of a current (high-impedance) amplifier, using feedback to reduce the output impedance.
Full details, including a practical design example, can be found at: https://robinet.co.uk/amplifier-design.
I have attached RTA spectra plots taken using REW, showing the performance of this design at 1 Watt into 8 Ohms, and at 100 Watts into 4 Ohms.
Comments will be welcome.
- The output impedance can be varied from a fraction of an Ohm, to several Kilo-ohms, by selecting two resistors.
- The amplifier is stable with virtually any load.
- It is very robust, and can survive accidental short-circuits.
- Total harmonic distortion is below 0.02% at 1 watt into 8 Ohms, up to 40kHz (This is a real measurement, not a simulation).
The principle on which the design is based is that of a current (high-impedance) amplifier, using feedback to reduce the output impedance.
Full details, including a practical design example, can be found at: https://robinet.co.uk/amplifier-design.
I have attached RTA spectra plots taken using REW, showing the performance of this design at 1 Watt into 8 Ohms, and at 100 Watts into 4 Ohms.
Comments will be welcome.
Hello from Saudi Arabia!
- By jareif
- Introductions
- 1 Replies
I have been scouring these forums for the past few months as my sons and I have embarked on a loudspeaker design project (two projects concurrently, actually). We have finally run into a roadblock which I don't know how to resolve and have concluded it is time to join the forum officially and seek some help!
We are an American family residing in Riyadh, Saudi Arabia.
Here are simple blender images of my two sons' designs:
We are an American family residing in Riyadh, Saudi Arabia.
Here are simple blender images of my two sons' designs:
How to fix these?
I have this speaker that stopped working and put my Yamaha into protect mode . I took it apart once but couldn’t find a x over or anything??? It seems a cord got loose and i attached it to the wrong spot .
Attachments
NE5532 is a popular opamp
- By lineup
- Analog Line Level
- 104 Replies
Look at these two circuits. They do the same.
The difference is the single and the dual supply.
Another difference is the capacitor C1 and C3.
Because the negative voltage at input pin C3 should be put 'upside down'.
This goes for all bipolar opamps with NPN input transistors.
And when using dual voltage supply.
If a bipolar opamp has PNP transistors input the C3 should be turned the other way.
Iron Pumpkin(s) and other smaller vegetable animals, Tips 'n' Tricks thread
Well, origin thread is here : Iron Pumpkin(s) and other smaller vegetable animals
If nothing else, read at least first several posts on linked page , to grasp enough info about concept itself.
This one having two purposes :
-placing all necessary info about final iteration,
-trying to layout clearer picture of what's fuss about,
-with edits of this first post - making comprehensive list of tips and tricks and funny fine details , and answering on any clever or dumb question you'll possibly have ......either here or further in thread
(3 purposes then , not two
)
edit at 22.05.2020. short how-to-do for Iron Pumpkin SE, referencing to post #2:
do not connect buffer output to Turtle
maximize trimpot R36 (measure across R39 to confirm max value)
R37 position is irrelevant for now
if you're sure that you connected everything properly, just power it on
set positive and negative rails to +/-12Vdc , with trimpots R9 and R10
power off, place DVMdc crocs across R34, power On then fiddle with R36 to set 20mV across R34, then fiddle with R37 to set 0mV DC offset at output
do everything the same with other channel, connect outputs of buffers to Turtle, enjoy
If nothing else, read at least first several posts on linked page , to grasp enough info about concept itself.
This one having two purposes :
-placing all necessary info about final iteration,
-trying to layout clearer picture of what's fuss about,
-with edits of this first post - making comprehensive list of tips and tricks and funny fine details , and answering on any clever or dumb question you'll possibly have ......either here or further in thread
(3 purposes then , not two
)edit at 22.05.2020. short how-to-do for Iron Pumpkin SE, referencing to post #2:
do not connect buffer output to Turtle
maximize trimpot R36 (measure across R39 to confirm max value)
R37 position is irrelevant for now
if you're sure that you connected everything properly, just power it on
set positive and negative rails to +/-12Vdc , with trimpots R9 and R10
power off, place DVMdc crocs across R34, power On then fiddle with R36 to set 20mV across R34, then fiddle with R37 to set 0mV DC offset at output
do everything the same with other channel, connect outputs of buffers to Turtle, enjoy
Full Range EQ
- By Nelson Pass
- Pass Labs
- 349 Replies
I am happy to present you with a project that I did 5 years ago which has served me well since.
- The Equalizer for Full Range Speakers Essentials Kit is available in the diyAudio Store.
Baby's first sub-filter
- By njswede
- Subwoofers
- 2 Replies
I found myself with time on my hands and enough parts to build a subwoofer and a plate amp (based on The Bog Standard) so I figured "why not?". I also needed a filter, so I drew one up. It's probably pretty naive. Just a simple preamp/buffer and a second order Sallen Key filter. I want to be able to set the cutoff frequency, so I made one of the resistors in the Sallen Key-filter variable. This works in SPICE as well as on breadboard. But is this too naive? I'm also getting about 50-60 degrees phase shift at the cutoff frequency. Should I be worried about this? Ideas for improvement are appreciated!
Design Phase - 35Hz Tapped Horn w/ Compression Chamber (Hog Scoop + Inverted Driver)
- By Databass
- Subwoofers
- 8 Replies
Design Phase - 35Hz Tapped Horn w/ Compression Chamber (Hog Scoop + Inverted Driver)
This project has been inspired by all the love for Hog Scoops... And the fair share of hate they get as well.
This will bee my first attempt at an 18" horn subwoofer.
Proposed plan is based on the well known "Hog Scoop",
a tried and tested free design hosted over on the freespeakerplans.com forum.
https://www.freespeakerplans.com/?view=article&id=31:hog-scoop
Drawn up nearly 20 years ago, this well proven classic has stood the test of time and is a very
clever piece of speaker box design, still to this day.
Credit for this creation must go to Stipe Ercegovic, more commonly known a Staiper, a well respected member on the Speakerplans Scoop subforum for a long time,
but he disappearred from there several years ago and doesn't seem to frequent these places anymore.
The Hog Scoop, technically an F1 hybrid of sorts, the offspring of two genetically similar species,
living a life somewhere between a tapped horn and a traditional back loaded "scoop".
A rear loaded horn with the bonus of the driver shooting into the horn path, or a tapped horn enclosure
equipped with a compression chamber.... Call it what you will, this quarter wave resonator is well capable of
hitting the low bass notes and producing high SPL when equipped with the right hardware.
So, I would like to run inverted drivers in a slightly tweaked version of this enclosure, something similar to the image attached to the end of this post.
These are the M4.18 subwoofers, made by MM-Acoustics in Europe, a Macedonian outfit headed by Marjan Milosevic, a regular poster and long time member over on SP.
My god, they look absolutely amazing, so business like.
This is the look I am going for.... They are absolutely badass indeed.
Anyway..... enough airy introductions, and down to business then !!
Hog Scoop Hornresp input parameters
First things first, I decided it would bee prudent to simulate a hog scoop with a driver in it's normal orientation first..... Cone side out.
This was to bee my baseline sim, a benchmark to work from before l went tweaking the original design.
And staight away I ran into problems.
For a start, the speakerplans.com forum isn't very active these days..... And a huge amount of information from back when it was is just lost.
Many externally hosted images are not there any more, there are many dead links, hosted plans, you name it, gone !!!
It didn't make my research easy but I did what I could with what I had.
That said, there were many helpful and informative threads to bee found amongst all the bickericking and the politics in the Scoop subforum.
So, lets discuss what was available to find on the net first.... Multiple posts regarding the Hog Scoop hornresp input parameters were scattered around the web....
And just not consistent.
I was hoping to pull some numbers out of a post or a sketch somewhere but straight off the bat, numbers and posts were conflicting.
Unfortunately, I found more than one set of digits, which only infuriated and confused me even more.
Here are the most posted (and reposted) HR Hog Scoop numbers, I beleive they orignally came from Staiper, and these ones were the most common to bee found online,
copy and pasted in at least 4 different places, so I am inclined to stick with the guy who originally penned the Hog Scoop design. He did create it after all.
Stipe Hog Scoop
S1 = 750
Con = 112.8
S2 = 1062
Con = 42
S3 = 1770
Con = 51
S4 = 2544
Con = 47
S5 = 5700
Vrc = 0
Lrc = 0
Fr = 0
Tal = 0
Vtc = 49456
Atc = 86
Re-posted by bitzo,
https://forum.speakerplans.com/forum_posts.asp?TID=16974&PID=214119&title=database-simulation#214119
toastyghost,
https://forum.speakerplans.com/forum_posts.asp?TID=16974&PID=727583&title=database-simulation#727583
Bee,
https://forum.speakerplans.com/forum_posts.asp?TID=72607&PID=828911&title=hog-scoop-drivers#828911
and salzburgsound system
The next set of input data numbers to bee found were these ones you see below.....
--------S1 = 750
Par = 0.10
S2 = 750
Par = 200.90
S3 = 1700
Par = 61.00
S4 = 4740
Par = 12.10
S5 = 5700
Vrc = 0
Ap1 = 0
Lrc = 0
Lpt = 0
Vtc = 37060
Atc = 1453.10
Posted by Heathrow B Line
https://forum.speakerplans.com/foru...=901195&title=scoop-hr-reference-guide#901195
epa
Freddi
And one more, with newer and revised numbers, taken from a post by user "epa" from 2014.
S1 = 750
Par = 0.10
S2 = 750
Par = 187.90
S3 = 1700
Par = 52.00
S4 = 4740
Par = 12.10
S5 = 5700
Vrc = 0
Lrc = 0
Ap1 = 0
Lpt = 0
Vtc = 41091
Atc = 2210.00
Posted by epa
Other than these three sets of input parameters, I did find a few posts by Staiper himself, modeling the Hog Scoop as an exponential horn,
in quite a numerically sparce fashion I must add.... It would seem this stripped down form of modelling came from Rog Mogale himself.
i will link after the following
---------->
Staiper Exponential Hog
S1 = 750
S2 = 5700
L = 260 EXP
Vtc = 36000 (with driver)
Atc = 1000
https://forum.speakerplans.com/forum_posts.asp?TID=8887&PID=218876&title=hog-scoop#218876
Staiper Exponential Again....
S1 = 750
S2 = 5700
L = 257 EXP
Vtc = 37000
Atc = 9000
https://forum.speakerplans.com/forum_posts.asp?TID=8329&PID=77534&title=tapped-horn-design#77534
And finally....... An attempt at simming a Hog Scoop by the man, Rog Mogale himself.
S1 = 750
S2 = 5700
L = 240 EXP
Vtc = 35000
Atc = 890
https://forum.speakerplans.com/forum_posts.asp?TID=8329&PID=77097&title=tapped-horn-design#77097
And here is a good thread full of interesting tit bits where Rog discusses his exponential scoop modelling methods with others.
https://forum.speakerplans.com/forum_posts.asp?TID=8329&PID=77097&title=tapped-horn-design#77097
A must read for anyone into this line of work.
Annd..... Time to take stock.
All my research and reading paid off, but unfortunately I still feel I do not have any concrete numbers for a Hog Scoop simulation binge.
So, I took some time out and drew up a scaled plan of the Hog, just enough to play with.
it gave me a much more definite idea of the direction I asm going in, speaker boxes ofthen quite literally build themselves as the project goes on.
Solutions are often just so obvious when you have the material object taking shape before your eyes.
And measurements can bee taken from the plan and scaled up to something that resembles real world numbers.
(Drawing attached)
And just to bee sure, I am going to get my hands on one side panel first, (18mm sheet board 986 x 950mm) and draw it out @ a life size scale on the floor.
Drivers for this design
I currently have 2 B&C 18TBX100 (4 ohm) belonging to a friend to use for the first 2 boxes and am debating which drivers to buy for the rest.
Quite likely B&C as well, I like the power handling (1500w) and price of the 18SW1OO.
When given the option, I usually buy 4 ohm versions of any driver when I can.
They can often bee had for the same price as their 8ohm equivalents but sometimes not. Sometimes they are just more hassle to obtain but I do make an effort to
use 4 ohm drivers when ever I can.
I am also open to other brands, I do know I need a certain type of driver to do well in these boxes and if one particular driver turns out to bee
especially suited to the task it will surely bee strongly considered.
So far, everything is going well.... The only other uncertainty I have right now is the design of the rear chamber.
I am not sure exactly how it will end up but I am confident the design (and build) process will answer it's own questions if and when they arise.
More on that in detail later.
Okay, I think I have written enough for now.... Any advice and criticism is warmly welcomed.
Please feel free to join me on my journey of discovery and don't bee shy to interject or comment if need bee.
This project has been inspired by all the love for Hog Scoops... And the fair share of hate they get as well.
This will bee my first attempt at an 18" horn subwoofer.
Proposed plan is based on the well known "Hog Scoop",
a tried and tested free design hosted over on the freespeakerplans.com forum.
https://www.freespeakerplans.com/?view=article&id=31:hog-scoop
Drawn up nearly 20 years ago, this well proven classic has stood the test of time and is a very
clever piece of speaker box design, still to this day.
Credit for this creation must go to Stipe Ercegovic, more commonly known a Staiper, a well respected member on the Speakerplans Scoop subforum for a long time,
but he disappearred from there several years ago and doesn't seem to frequent these places anymore.
The Hog Scoop, technically an F1 hybrid of sorts, the offspring of two genetically similar species,
living a life somewhere between a tapped horn and a traditional back loaded "scoop".
A rear loaded horn with the bonus of the driver shooting into the horn path, or a tapped horn enclosure
equipped with a compression chamber.... Call it what you will, this quarter wave resonator is well capable of
hitting the low bass notes and producing high SPL when equipped with the right hardware.
So, I would like to run inverted drivers in a slightly tweaked version of this enclosure, something similar to the image attached to the end of this post.
These are the M4.18 subwoofers, made by MM-Acoustics in Europe, a Macedonian outfit headed by Marjan Milosevic, a regular poster and long time member over on SP.
My god, they look absolutely amazing, so business like.
This is the look I am going for.... They are absolutely badass indeed.
Anyway..... enough airy introductions, and down to business then !!
Hog Scoop Hornresp input parameters
First things first, I decided it would bee prudent to simulate a hog scoop with a driver in it's normal orientation first..... Cone side out.
This was to bee my baseline sim, a benchmark to work from before l went tweaking the original design.
And staight away I ran into problems.
For a start, the speakerplans.com forum isn't very active these days..... And a huge amount of information from back when it was is just lost.
Many externally hosted images are not there any more, there are many dead links, hosted plans, you name it, gone !!!
It didn't make my research easy but I did what I could with what I had.
That said, there were many helpful and informative threads to bee found amongst all the bickericking and the politics in the Scoop subforum.
So, lets discuss what was available to find on the net first.... Multiple posts regarding the Hog Scoop hornresp input parameters were scattered around the web....
And just not consistent.
I was hoping to pull some numbers out of a post or a sketch somewhere but straight off the bat, numbers and posts were conflicting.
Unfortunately, I found more than one set of digits, which only infuriated and confused me even more.
Here are the most posted (and reposted) HR Hog Scoop numbers, I beleive they orignally came from Staiper, and these ones were the most common to bee found online,
copy and pasted in at least 4 different places, so I am inclined to stick with the guy who originally penned the Hog Scoop design. He did create it after all.
Stipe Hog Scoop
S1 = 750
Con = 112.8
S2 = 1062
Con = 42
S3 = 1770
Con = 51
S4 = 2544
Con = 47
S5 = 5700
Vrc = 0
Lrc = 0
Fr = 0
Tal = 0
Vtc = 49456
Atc = 86
Re-posted by bitzo,
https://forum.speakerplans.com/forum_posts.asp?TID=16974&PID=214119&title=database-simulation#214119
toastyghost,
https://forum.speakerplans.com/forum_posts.asp?TID=16974&PID=727583&title=database-simulation#727583
Bee,
https://forum.speakerplans.com/forum_posts.asp?TID=72607&PID=828911&title=hog-scoop-drivers#828911
and salzburgsound system
The next set of input data numbers to bee found were these ones you see below.....
--------S1 = 750
Par = 0.10
S2 = 750
Par = 200.90
S3 = 1700
Par = 61.00
S4 = 4740
Par = 12.10
S5 = 5700
Vrc = 0
Ap1 = 0
Lrc = 0
Lpt = 0
Vtc = 37060
Atc = 1453.10
Posted by Heathrow B Line
https://forum.speakerplans.com/foru...=901195&title=scoop-hr-reference-guide#901195
epa
Freddi
And one more, with newer and revised numbers, taken from a post by user "epa" from 2014.
S1 = 750
Par = 0.10
S2 = 750
Par = 187.90
S3 = 1700
Par = 52.00
S4 = 4740
Par = 12.10
S5 = 5700
Vrc = 0
Lrc = 0
Ap1 = 0
Lpt = 0
Vtc = 41091
Atc = 2210.00
Posted by epa
Other than these three sets of input parameters, I did find a few posts by Staiper himself, modeling the Hog Scoop as an exponential horn,
in quite a numerically sparce fashion I must add.... It would seem this stripped down form of modelling came from Rog Mogale himself.
i will link after the following
---------->
Staiper Exponential Hog
S1 = 750
S2 = 5700
L = 260 EXP
Vtc = 36000 (with driver)
Atc = 1000
https://forum.speakerplans.com/forum_posts.asp?TID=8887&PID=218876&title=hog-scoop#218876
Staiper Exponential Again....
S1 = 750
S2 = 5700
L = 257 EXP
Vtc = 37000
Atc = 9000
https://forum.speakerplans.com/forum_posts.asp?TID=8329&PID=77534&title=tapped-horn-design#77534
And finally....... An attempt at simming a Hog Scoop by the man, Rog Mogale himself.
S1 = 750
S2 = 5700
L = 240 EXP
Vtc = 35000
Atc = 890
https://forum.speakerplans.com/forum_posts.asp?TID=8329&PID=77097&title=tapped-horn-design#77097
And here is a good thread full of interesting tit bits where Rog discusses his exponential scoop modelling methods with others.
https://forum.speakerplans.com/forum_posts.asp?TID=8329&PID=77097&title=tapped-horn-design#77097
A must read for anyone into this line of work.
Annd..... Time to take stock.
All my research and reading paid off, but unfortunately I still feel I do not have any concrete numbers for a Hog Scoop simulation binge.
So, I took some time out and drew up a scaled plan of the Hog, just enough to play with.
it gave me a much more definite idea of the direction I asm going in, speaker boxes ofthen quite literally build themselves as the project goes on.
Solutions are often just so obvious when you have the material object taking shape before your eyes.
And measurements can bee taken from the plan and scaled up to something that resembles real world numbers.
(Drawing attached)
And just to bee sure, I am going to get my hands on one side panel first, (18mm sheet board 986 x 950mm) and draw it out @ a life size scale on the floor.
Drivers for this design
I currently have 2 B&C 18TBX100 (4 ohm) belonging to a friend to use for the first 2 boxes and am debating which drivers to buy for the rest.
Quite likely B&C as well, I like the power handling (1500w) and price of the 18SW1OO.
When given the option, I usually buy 4 ohm versions of any driver when I can.
They can often bee had for the same price as their 8ohm equivalents but sometimes not. Sometimes they are just more hassle to obtain but I do make an effort to
use 4 ohm drivers when ever I can.
I am also open to other brands, I do know I need a certain type of driver to do well in these boxes and if one particular driver turns out to bee
especially suited to the task it will surely bee strongly considered.
So far, everything is going well.... The only other uncertainty I have right now is the design of the rear chamber.
I am not sure exactly how it will end up but I am confident the design (and build) process will answer it's own questions if and when they arise.
More on that in detail later.
Okay, I think I have written enough for now.... Any advice and criticism is warmly welcomed.
Please feel free to join me on my journey of discovery and don't bee shy to interject or comment if need bee.
Tokin DEFISIT Duo Capacitor Output Stage Amplifier
Here is my latest Tokin SIT amplifier. It is a DEFISIT amp (Depletion Enhancement Follower SIT) output stage based on Nelson's First Watt SIT-5 output stage. Diyers more knowledgeable than me picked apart what information Nelson provided in his SIT-5 owners' manual (https://www.diyaudio.com/community/threads/first-watt-sit5.418023/), and I rode on their coattails and came up with this version.
My build is only the output stage, and it incorporates the duo output capacitor arrangement which can be tweaked to adjust the amount of current amplification that the mosfet part of the DEFISIT push-pull output contributes to the total current amplification. This is a departure from the regular DEFISIT amplifier, where the SIT and mosfet both fully contribute to the total current amplification.
Here are a couple of LTSpice simulations. I did many simulations, but these two are what I based my design on. I chose -47VDC for one sim since I intended to build it using one of my existing amplifier chassis and power supply. I chose the -63VDC for the other since that is a reasonable voltage that will take advantage of the power capability of the THF-51S and still keep the power supply voltage reasonable for capacitor voltage and heat sink heat dissipation.
As shown in the simulation results (47VDC power supply and 2.0A Iq), the measured current through C4 connected to the SIT drain was 361mA peak, the measured current through C7 connected to the mosfet drain was 150mA, for a total of 511mA. As a check the current measured through the speaker, R8, was 509mA - close enough. So the contribution of the mosfet was 150mA/511mA = 29%.
I have not included the LTSpice screen shots of power output but the 8 Ohm power output was nearly 23W at 1% THD and 4 Ohm power output was nearly 40W at 1% THD.
63VDC PS 2A 8R 1Watt:
63VDC PS 2A AC signal current through C4, C7, and 8R Speaker:
47VDC PS 2A 8R 1Watt:
47VDC PS 2A AC signal current through C4, C7, and 8R Speaker:
As mentioned I decided to build the 47VDC version. The chassis and power supply is from my BAF2015 Amplifier - A SIT Mu Follower Revisited With Feedback (https://www.diyaudio.com/community/...t-mu-follower-revisited-with-feedback.408193/). The power supply is CLC, comprising 2x22mF - Hammond 156B - 2x22mF, and an Antek AS-3218 transformer per channel for full dual mono construction.
I put together a PCB design and sent it off to JLCPCB for fabrication. In addition to stuffing the PCB once I received it, I also changed the CLC filter from V+ supply to V- supply.
Initial power-up and subsequent Iq and SIT Vds adjustments went smoothly, and Iq and SIT Vds were stable.
Next up was testing with an 1kHz signal and distortion measurements. Unfortunately when powered up with an AC line powered 1kHz oscillator connected, the amp immediately blew the powerline fuse. So it was trouble shooting time. After checking the schematic and pcb, checking that the input capacitor was not faulty, and not finding any visible ground shorts with the meter, I was baffled.
I knew that the issue was mostly likely a grounding problem and that it only manifested itelf when an input device was connected to the amplifier. Luckily a thought came to me fairly quickly - when I changed the CLC filter from V+ to V- supply, I forgot to move the power supply connection to safety ground on the CLC filter board. The correction was made and success. Only one fuse was permanently damaged.
The dim bulb tester came in handy here as once the fuse blew, the dim bulb tester went in and I was able to probe around with power and not blow anything. In addition to using it during trouble shooting, I always use it for first power-up testing of power supplies during various stages of construction and first power-up testing of audio circuits.
As for the amplifier supply not shorting with no input device connected but shorting with an input device connected, I gave it some thought. The power supply was for V-, with V- from the supply connected as power to the amplifier circuit. V+ from the supply was connected to the amplifier circuit board as ground. The V- from the supply was ground in the previous amplifier but I forgot to change it so it was now incorrectly connected to chassis safety ground. With no input device connected to the amplifier circuit, the power to the amplifier board was floating. Although the V- was also connected to the chassis safety ground and to the powerline/IEC ground, there was no other direct connection to V+, so no short. The live from the powerline/IEC was connected to the transformer primary, which was isolated from the transformer secondary. Also the speaker and input jacks were isolated from the chassis. So with no complete direct connection of V- to V+, the current can only flow through the audio circuit. The chassis was connected to V- but there was no path for the current to flow from the chassis to power supply V+.
When the oscillator was connected to the amplifier input, the circuit was completed, current flowed, and the fuse blew. That was because the oscillator was AC powered and had a safety ground connection. So the oscillator line safety ground connected to the oscillator power supply ground, then connected to the oscillator signal ground, then connected to the amplifier signal ground, then connected to the amplifier V+. The oscillator safety ground is also connected to the amplifier safety ground through the line ground, and the amplifier safety ground is connected to amplifier V-. The net result was amplifier V+ and amplifier V- were connected together - a short circuit. There was a CL60 thermistor at the amplifier power supply ground connection. That would have limited the short circuit current: 47V/10R = 4.7A. Fuse was 2.5A slow blow.
I have swapped power supply polarity before but had always remembered to switch the safety ground connected, until this time.
So always be careful. Electricity can kill.
My build is only the output stage, and it incorporates the duo output capacitor arrangement which can be tweaked to adjust the amount of current amplification that the mosfet part of the DEFISIT push-pull output contributes to the total current amplification. This is a departure from the regular DEFISIT amplifier, where the SIT and mosfet both fully contribute to the total current amplification.
Here are a couple of LTSpice simulations. I did many simulations, but these two are what I based my design on. I chose -47VDC for one sim since I intended to build it using one of my existing amplifier chassis and power supply. I chose the -63VDC for the other since that is a reasonable voltage that will take advantage of the power capability of the THF-51S and still keep the power supply voltage reasonable for capacitor voltage and heat sink heat dissipation.
As shown in the simulation results (47VDC power supply and 2.0A Iq), the measured current through C4 connected to the SIT drain was 361mA peak, the measured current through C7 connected to the mosfet drain was 150mA, for a total of 511mA. As a check the current measured through the speaker, R8, was 509mA - close enough. So the contribution of the mosfet was 150mA/511mA = 29%.
I have not included the LTSpice screen shots of power output but the 8 Ohm power output was nearly 23W at 1% THD and 4 Ohm power output was nearly 40W at 1% THD.
63VDC PS 2A 8R 1Watt:
63VDC PS 2A AC signal current through C4, C7, and 8R Speaker:
47VDC PS 2A 8R 1Watt:
47VDC PS 2A AC signal current through C4, C7, and 8R Speaker:
As mentioned I decided to build the 47VDC version. The chassis and power supply is from my BAF2015 Amplifier - A SIT Mu Follower Revisited With Feedback (https://www.diyaudio.com/community/...t-mu-follower-revisited-with-feedback.408193/). The power supply is CLC, comprising 2x22mF - Hammond 156B - 2x22mF, and an Antek AS-3218 transformer per channel for full dual mono construction.
I put together a PCB design and sent it off to JLCPCB for fabrication. In addition to stuffing the PCB once I received it, I also changed the CLC filter from V+ supply to V- supply.
Initial power-up and subsequent Iq and SIT Vds adjustments went smoothly, and Iq and SIT Vds were stable.
Next up was testing with an 1kHz signal and distortion measurements. Unfortunately when powered up with an AC line powered 1kHz oscillator connected, the amp immediately blew the powerline fuse. So it was trouble shooting time. After checking the schematic and pcb, checking that the input capacitor was not faulty, and not finding any visible ground shorts with the meter, I was baffled.
I knew that the issue was mostly likely a grounding problem and that it only manifested itelf when an input device was connected to the amplifier. Luckily a thought came to me fairly quickly - when I changed the CLC filter from V+ to V- supply, I forgot to move the power supply connection to safety ground on the CLC filter board. The correction was made and success. Only one fuse was permanently damaged.
The dim bulb tester came in handy here as once the fuse blew, the dim bulb tester went in and I was able to probe around with power and not blow anything. In addition to using it during trouble shooting, I always use it for first power-up testing of power supplies during various stages of construction and first power-up testing of audio circuits.
As for the amplifier supply not shorting with no input device connected but shorting with an input device connected, I gave it some thought. The power supply was for V-, with V- from the supply connected as power to the amplifier circuit. V+ from the supply was connected to the amplifier circuit board as ground. The V- from the supply was ground in the previous amplifier but I forgot to change it so it was now incorrectly connected to chassis safety ground. With no input device connected to the amplifier circuit, the power to the amplifier board was floating. Although the V- was also connected to the chassis safety ground and to the powerline/IEC ground, there was no other direct connection to V+, so no short. The live from the powerline/IEC was connected to the transformer primary, which was isolated from the transformer secondary. Also the speaker and input jacks were isolated from the chassis. So with no complete direct connection of V- to V+, the current can only flow through the audio circuit. The chassis was connected to V- but there was no path for the current to flow from the chassis to power supply V+.
When the oscillator was connected to the amplifier input, the circuit was completed, current flowed, and the fuse blew. That was because the oscillator was AC powered and had a safety ground connection. So the oscillator line safety ground connected to the oscillator power supply ground, then connected to the oscillator signal ground, then connected to the amplifier signal ground, then connected to the amplifier V+. The oscillator safety ground is also connected to the amplifier safety ground through the line ground, and the amplifier safety ground is connected to amplifier V-. The net result was amplifier V+ and amplifier V- were connected together - a short circuit. There was a CL60 thermistor at the amplifier power supply ground connection. That would have limited the short circuit current: 47V/10R = 4.7A. Fuse was 2.5A slow blow.
I have swapped power supply polarity before but had always remembered to switch the safety ground connected, until this time.
So always be careful. Electricity can kill.
symphonic-mpd
- By papalius
- Vendor's Bazaar
- 417 Replies
The content of this thread is my personal opinion and does not represent performance based on objective metrics.
Information about symphonic-mpd, a CRAFTED LINUX for Raspberry Pi4.
It has been developed to target audiophile who want high quality music playback on I2S output.
Official Forum
symphonic-mpd
If you are interested, please ask your questions in this thread.
In order to use the SD images of this distribution, you need to join the official forum.
If you would like to join, please email me below with your handle name.
symphonic.mpd@gmail.com
kubotayo@jcom.home.ne.jp
mark.create@gmail.com
Information about symphonic-mpd, a CRAFTED LINUX for Raspberry Pi4.
It has been developed to target audiophile who want high quality music playback on I2S output.
Official Forum
symphonic-mpd
If you are interested, please ask your questions in this thread.
If you would like to join, please email me below with your handle name.
symphonic.mpd@gmail.com
kubotayo@jcom.home.ne.jp
mark.create@gmail.com
Troels Gravesen AtiRi
- By noamgeller
- Multi-Way
- 22 Replies
So, the kit of the AtiRi has been bought and I am thinking of pumping it up and make a Kawero Classic clone (kind of) out of it.
But I need your help regarding the bass segment.
My plan is simple, take the two way AtiRi (15Liter) and put on a 40Liter bass reflex cabinet. untill now same as Kawero.
The woofer I will use for the 40Liter is the 10inch Faitalpro RS350. it will be driven by Hypex Fa501.
Now, I really really want to nail this bass, clean accurate, powerful.
So the following ideas are:
1. 40liter-bass reflex with one RS350 10inch driver
2. 40liter- closed cabinet with one RS350 10 inch driver -infinite baffle
3. 40liter- Closed cabinet with Two!! RS350 10 inch driver
I know its more about opinions and everything is a compromise but it would be great to hear your preferences.
Thanks!
But I need your help regarding the bass segment.
My plan is simple, take the two way AtiRi (15Liter) and put on a 40Liter bass reflex cabinet. untill now same as Kawero.
The woofer I will use for the 40Liter is the 10inch Faitalpro RS350. it will be driven by Hypex Fa501.
Now, I really really want to nail this bass, clean accurate, powerful.
So the following ideas are:
1. 40liter-bass reflex with one RS350 10inch driver
2. 40liter- closed cabinet with one RS350 10 inch driver -infinite baffle
3. 40liter- Closed cabinet with Two!! RS350 10 inch driver
I know its more about opinions and everything is a compromise but it would be great to hear your preferences.
Thanks!
3-way - port tube placement and braces
Hi all
I'm trying to design a 3-way speaker based on mid-range and tweeter I already have (used in a 2 way speaker some years ago).
I decided to add SB26SFCL38-8 to these 2 drivers in bass reflex configuration. The volume for the woofer will be around 88L with a resonant frequency is 27Hz.
I want create a cabinet with hard plywood 19mm with external size WxDxH 38x55x63 (the height is a constraint).
The cabinet will have a "small room" for the mid and tweeter of about 8L.
The port tube will have diameter of 9,2 cm and length of 22,5 cm
I have 2 main doubts now (may be more 🙂)
1. Where put the port tube. I have not enough space below the woofer do I would like to place it upper. Something like this...
I also did a try with 2 port of 6,6 cm and 24,5 cm length below the woofer.
What do you think is the best solution?
2. How many braces, where to place them and how shape them. I'm not so expert about this aspect.
I'm trying to design a 3-way speaker based on mid-range and tweeter I already have (used in a 2 way speaker some years ago).
I decided to add SB26SFCL38-8 to these 2 drivers in bass reflex configuration. The volume for the woofer will be around 88L with a resonant frequency is 27Hz.
I want create a cabinet with hard plywood 19mm with external size WxDxH 38x55x63 (the height is a constraint).
The cabinet will have a "small room" for the mid and tweeter of about 8L.
The port tube will have diameter of 9,2 cm and length of 22,5 cm
I have 2 main doubts now (may be more 🙂)
1. Where put the port tube. I have not enough space below the woofer do I would like to place it upper. Something like this...
I also did a try with 2 port of 6,6 cm and 24,5 cm length below the woofer.
What do you think is the best solution?
2. How many braces, where to place them and how shape them. I'm not so expert about this aspect.
For Sale ATC SB76-314SC
For sale a pair of ATC SB75-314S in very good condition and with fresh new surrounds.
They can be used as well to replace the SB75-314SL because they behave and measure equal to those. Just Some better an more linear roll off in the SL. The SL has not a resonance peak more than 12dB below crossover point at 500/600Hz.
Price for the pair will be 450€ + PP fees + Shipping at cost.
They can be used as well to replace the SB75-314SL because they behave and measure equal to those. Just Some better an more linear roll off in the SL. The SL has not a resonance peak more than 12dB below crossover point at 500/600Hz.
Price for the pair will be 450€ + PP fees + Shipping at cost.
Schematic request: Alesis BRC (Big Remote Control)
I looked around and can't find a good place to file this thread, so if I missed something, Mods, please feel free to relocate.
I am about to purchase an Alesis BRC which will (hopefully) control my HD24 [24-track hard disc recorder]. It was originally designed to control many ADAT machines, daisy chained together. ADAT uses SVHS tape for audio recording. Anyway the HD24 is 24 tracks od digital recording onto hot-swappable hard drives. But since access is orders of magnitude faster on the HD than spooling tape, there can be sync issues... (it CAN allegedly daisy chain HD24s to provide 48+ tracks, up to 128 max or something silly like that)
I have the Alesis service manual, and it indicates an appendix for the schematics, but they are not there. It must have been a separate file or insert added at the repair facility. I do have the "confidential" service tech final testing procedures at the end of the copy of the manual I have so it seems to be "complete".
Please have a look around and see if you have one or can point me to an online source. I can't find it anywhere and I was digging pretty deep...
Thanks in advance for any help!
I am about to purchase an Alesis BRC which will (hopefully) control my HD24 [24-track hard disc recorder]. It was originally designed to control many ADAT machines, daisy chained together. ADAT uses SVHS tape for audio recording. Anyway the HD24 is 24 tracks od digital recording onto hot-swappable hard drives. But since access is orders of magnitude faster on the HD than spooling tape, there can be sync issues... (it CAN allegedly daisy chain HD24s to provide 48+ tracks, up to 128 max or something silly like that)
I have the Alesis service manual, and it indicates an appendix for the schematics, but they are not there. It must have been a separate file or insert added at the repair facility. I do have the "confidential" service tech final testing procedures at the end of the copy of the manual I have so it seems to be "complete".
Please have a look around and see if you have one or can point me to an online source. I can't find it anywhere and I was digging pretty deep...
Thanks in advance for any help!
NSM4202A LED Display Module Replacement for Philips / Sony CDM Transports
- By NoNameXII
- Digital Source
- 16 Replies
I have an old Krell MD-2 CD turntable, and (among other issues) several segments have gone out on the LED display. After looking around online, I found one person in France that had built a replacement, but details were kind of scarce, so tried to reverse engineer my display module based upon the tidbits of information that I was able to uncover.
After hooking it up to a scope, it appeared to use SPI (keep in mind that I'm not very smart), but I just got rubbish when I created a small Arduino program to read the data, so I traipsed through the available LED drivers on DigiKey, and came across the MM5450 as one of the very few chips that didn't require I2C. Upon reviewing the data stream again, it appeared to fit with what was required to drive this chip. Anyway, I did the best that I could to guess the pinout of my existing display board (it uses an unmarked glob to hold down the IC die), and was able to reconcile it with the MM5450 pinout, so I made up a board, bought some parts, and tried it out. It appears to be fully functional, so I thought that I would share it here so that others can create a replacement for themselves as necessary. I'm kind of hoping that since this hardware is over 25 years old (and apparently out of production for quite some time) that Philips won't mind too much the publishing of plans for a replacement...
Anyway, here goes with the information:
Feel free to use this information however you wish, so long as you don't make anyone pay for it. I don't care if you charge someone to assemble a board for them or something (it's none of my business), but the information should be kept in the open. I abhor GPL-like licensing, but I do expect you to not be a turd.
I am just a hobbyist (and a really unintelligent one at that), so I do not make any representation that information is accurate, safe, or suitable for any purpose, even a purpose that may be implied by the information. In other words, I did the best that I could, it worked for me, but it's not on me if you hurt yourself or start a fire or something.
I have the board shared at OSH Park (https://oshpark.com/shared_projects/P3nC9ISV) for convenience. I make nothing from this link or design (AFIAK), and I don't care from where you order your board.
BOM:
Electrical Schematic:
View attachment NSM4202A Schematic.pdf
Front of PCB:
Back of PCB:
Gerbers for PCB:
View attachment NSM4202A.zip
DipTrace Schematic and Board Files:
View attachment NSM4202A DipTrace Files.zip
After hooking it up to a scope, it appeared to use SPI (keep in mind that I'm not very smart), but I just got rubbish when I created a small Arduino program to read the data, so I traipsed through the available LED drivers on DigiKey, and came across the MM5450 as one of the very few chips that didn't require I2C. Upon reviewing the data stream again, it appeared to fit with what was required to drive this chip. Anyway, I did the best that I could to guess the pinout of my existing display board (it uses an unmarked glob to hold down the IC die), and was able to reconcile it with the MM5450 pinout, so I made up a board, bought some parts, and tried it out. It appears to be fully functional, so I thought that I would share it here so that others can create a replacement for themselves as necessary. I'm kind of hoping that since this hardware is over 25 years old (and apparently out of production for quite some time) that Philips won't mind too much the publishing of plans for a replacement...
Anyway, here goes with the information:
Feel free to use this information however you wish, so long as you don't make anyone pay for it. I don't care if you charge someone to assemble a board for them or something (it's none of my business), but the information should be kept in the open. I abhor GPL-like licensing, but I do expect you to not be a turd.
I am just a hobbyist (and a really unintelligent one at that), so I do not make any representation that information is accurate, safe, or suitable for any purpose, even a purpose that may be implied by the information. In other words, I did the best that I could, it worked for me, but it's not on me if you hurt yourself or start a fire or something.
I have the board shared at OSH Park (https://oshpark.com/shared_projects/P3nC9ISV) for convenience. I make nothing from this link or design (AFIAK), and I don't care from where you order your board.
BOM:
- U1 - Micrel MM5450 (PLCC-44) LED Display Driver
- DS1-DS4 - Kingbright ACSA03-41SGWA-F01 7-Segment Common-Anode LED Display (Green, other colors probably available)
- D1-D2 - 0603 SMD LED (Green for use with the specified green LED digits)
- R1 - 7.5kOhm (or higher) 1206 SMD Resistor (controls brightness)
- C1 - 1000pF 1206 SMD Capacitor
- J1-J3 - 0.1" header system of your choice
Electrical Schematic:
View attachment NSM4202A Schematic.pdf
Front of PCB:
Back of PCB:
Gerbers for PCB:
View attachment NSM4202A.zip
DipTrace Schematic and Board Files:
View attachment NSM4202A DipTrace Files.zip
Why would an amp designer intentionally use different OPT impedances for Left vs. Right?
- By wparks
- Tubes / Valves
- 22 Replies
(I posted this on the AK forum, and so far nobody can give me a good answer, so a gold star to the one who can . . .)
So I'm thinking for my next tube amp build I would really like to do a little integrated 6AQ5 push-pull, so I was researching some of the greats, and apparently the Voice of Music 1404 integrated amplifier (581 console) really stands out as a super performer based upon many comments I have read.
I have a one page schematic, as well as a pdf copy of the SAMs posted below for the model 581 console, which used essentially the same chassis. It very clearly shows that the left and right output transformers are different- one has a primary impedance of 5700 ohms, the other is 7000 ohms. This is confirmed in the schematic, which indicates a different DCR for each primary (325 vs 340 ohms per side). These are not two "alternates" or an accident, this is a deliberate design choice to use a different load line (but same operating point) for left versus right.
Does anyone know why this would be done? I have never seen that before.
BTW I think the super cheap 6AQ5 (essentially a 6V6 in a 7-pin peanut) will be very fun to play with- guitar amps are using them like crazy but still seem to be quite overlooked in new audio builds.
So I'm thinking for my next tube amp build I would really like to do a little integrated 6AQ5 push-pull, so I was researching some of the greats, and apparently the Voice of Music 1404 integrated amplifier (581 console) really stands out as a super performer based upon many comments I have read.
I have a one page schematic, as well as a pdf copy of the SAMs posted below for the model 581 console, which used essentially the same chassis. It very clearly shows that the left and right output transformers are different- one has a primary impedance of 5700 ohms, the other is 7000 ohms. This is confirmed in the schematic, which indicates a different DCR for each primary (325 vs 340 ohms per side). These are not two "alternates" or an accident, this is a deliberate design choice to use a different load line (but same operating point) for left versus right.
Does anyone know why this would be done? I have never seen that before.
BTW I think the super cheap 6AQ5 (essentially a 6V6 in a 7-pin peanut) will be very fun to play with- guitar amps are using them like crazy but still seem to be quite overlooked in new audio builds.
Attachments
Apollo Light Drive
- By gerrittube
- Power Supplies
- 4 Replies
Light fantastic
“The P1 power amplifier requires a super clean high current power supply to turn the low voltage line level music signal into hundreds of watts of output power. To do this, Siltech designed the Apollo Light Drive. A super-strong AC-powered light source is used to drive a photo-electric cell, giving a totally noise-free, galvanically isolated DC output. This then drives the amplifier’s output stage, keeping it absolutely immune from mains-born distortion. The idea behind this is not new, but its execution in a high powered amplifier is extremely challenging. The result is ultra-clean, low distortion power – and lots of it.”
Has anyone tried DIYing this concept?
https://www.siltechcables.com/saga-amplifier-system/
ZEN Amplifier Mini with IRF610 as Headphone Amplifier for 32 Ohm
The ZEN Amplifier concept is simple. But it works great.
Here is such an amplifier but with less current and uses IRF610 as MOSFET.
It makes a simple and sweet headphone amp.
Building shouldn't be difficult.
The heatsinking it takes is not so much.
There is some THD, but it is mainly 2nd harmonic.
So, it would be good listening.
The amp is designed for 32 Ohms headphones.
For other impedances it may need tweaking to make it alright.
Here is such an amplifier but with less current and uses IRF610 as MOSFET.
It makes a simple and sweet headphone amp.
Building shouldn't be difficult.
The heatsinking it takes is not so much.
There is some THD, but it is mainly 2nd harmonic.
So, it would be good listening.
The amp is designed for 32 Ohms headphones.
For other impedances it may need tweaking to make it alright.
