Hi gang,

Long-term lurker here on DiyAudio (on my phone normally). I apologise if this is in the wrong section.

I picked up some second hand Jamo E875 speakers in Australia but one of the drivers don't have it's cone piece anymore and is completely exposed.

I'm unable to find any direct replacement part for it - would anyone have any other recommendation on what could fit as a replacement?

https://i.imgur.com/ZMNBKyY.jpg

Thanks,
Hein.

Sold

I need a way to enable others in my household to access and play music from my MacPro (not a laptop).
Background follows...

Technology

Mine


My wife's


Stereo system

MacPro has a hardwired digital connection to my stereo system's Hypex plate amps with DSP.
As it stands the system has no other available inputs (wireless or bluetooth) into the stereo system.

So, I can not send music directly from any other device to the stereo system. The stereo has no other inputs remote or otherwise.

I use Apple's Music app. Works perfectly.

Goal

Enable my wife's or other's iPad Pro to remotely access my Mac Pro's Music app. So she can play music on the attached stereo system.

Note: She has a different AppleID than I do, but I would think a way must exist to permission her to control things.

I use Apple's Remote.app on my iPad to control the stereo when I sit in my listening spot (away from my desktop), but I can't figure out how to make this work from my wife's iPad.

Thoughts and guidance appreciated.

Hey everyone, just wanted to post quick that my "real job" has been really busy, so I'm even slower than usual in answering emails and what not.

Hi i was looking at the part list for the lk-85 complete list of all components and was comparing the it to the parts in my lk-85 and i spotted 3 transistors that dont match , they are the input transistors C1SSB on the part list it says they should be 2C4391

can anyone help me find info on these C1SSB SMT transistors should i change them for the 2C4391

thanks

Hey folks. I've found this thing that I think is interesting, and I'm trying to understand how it works. I think DSP is fun and cool, but don't have any education in the how-it-works department.

Here's the thing:
Stereo to 5.1 Channel Converter in Max/MSP

I'm particularly interested in the LMS-based upmixing section, mostly about center channel synthesis. I wasn't able to download the MAX patch from the link, but but I was able to recreate the important bits in MAX, once I figured out the gen~ function. I emailed the author about the broken DL link, but no response.

(Max / MSP What is Max? | Cycling '''74 pretty cool tool for sound monkeying on yer computer. Free evaluation.)

From the link:
"The least-mean-square (LMS)-based method uses a decorrelation technique using the LMS algorithm. One of the original stereo channels is used as the desired signal d👎, and the other is considered as the input, x👎, of the FIR filter. The output y👎 represents the correlated part, which is used as the center channel, whereas the error e👎 that is the uncorrelated part is considered as the surround channel."

So I though that center channel y👎 would contain the common content and I could subtract that from the L and R channel (and double it) and play
(Left only content) - (L/R common content) - (Right only content)
across a 3 channel front and it would be cool.

But it doesn't work like that. Why? I made a patch with a tone generator with a L/R panner on front feeding into the modified LMS upmixer (ctr subtracted from L and R), running into a set of meters on the upmixers output, and it doesn't seem to function like I expected. (It doesn't seem to work right on listening to music either.) In fact, the REAR channels are set up as Left minus Center, hmmm.

Trying to figure out how it works leads me to more detailed questions, but I figure I'll try to get some educated individual to take the bait here before I spend a lot of column-inches laying out my ignorance. This is already getting into TL-DR territory.

Anyone out there interested in explaining this thing?

I had some magnets left from earlier projects, so I made this contraption for fun.
Its a bass driver with nine rows with 19 magnets in each row. The magnets size is 4x10x40mm, and a 12Um Mylar sheet stretched 4 mm over the magnets.

The perforated metal is a shelf from IKEA called "Bottna".

Today, it has four loops of 0.32 (28 gauge) copper wire. Each loop has four turns in the magnet gap. The loops are connected in series, giving a total of 5 Ohms and sensitivity around 85 dB/2,83 volt

The wires are taped to the Mylar using Kapton tape for easy replacement. (works surprisingly well, with very low distortion)

The big question: How to make the most Spl efficient wiring? Maybe using thinner wire in parallel?

Any suggestions?

Regards/ Jonas

I recently sold a USB PC oscilloscope pcb on ebay.
Got an email and it said he was very happy with the scope after fixing all the dry solder joints !

I have been soldering for 40+years.
I have a Radio, TV, electronics examination board pass in practical electronic skills from 1981.

If it was so bad how come it was fully tested and worked ok for me ?
I can only guess the electrons were jumping the gaps ?

I am building a preamp with a separate power supply chassis. I searched for threads discussing this topic, but didn't find one that was a good match to what I am planning.

My power supply chassis will have a custom transformer to drive four dual-rail supplies (filtered, but not regulated) for analog circuits and one single-rail regulated supply for digital circuits. The IEC ground will be connected to the chassis ground. I am currently planning a 14 conductor umbilical so all supplies will have their own ground connection, so all these supplies will be floating with respect to chassis ground and to each other.

The preamp chassis will use four dual-channel UltraBib regulators - two for each channel (one supplying +/- 17v for Salas DCG3 amps, and one supplying +/- 10v for op-amp circuits).

I'm assuming I want to have a single star grounding point in the preamp chassis to provide a common grounding point for each of these separate circuits. Do I need to somehow connect the preamp chassis ground to the PS chassis ground? If so, I assume I will need a 15th conductor in my umbilical and connect through a ground-break circuit, but I'd rather avoid this unless it's really necessary since I'd have to use a bigger umbilical connector.

Thanks.

When some simple power IC project is finished people often need to connect headphones to it. There is more than enough power and in that way one does not need to build separate headphones amp, saving hardware and work. I compared several schematics used by Japanese companies and noticed that usually headphones output is connected in parallel with speakers output using just one series resistor in the range from 220R to 680R rated 0.5W or 1W. This is simple and indeed works quite well in practice. There is one downside that phones are driven from high impedance and that creates some frequency irregularities. Is there better way to connect headphones in parallel with speaker outputs. Would it be better to use two resistor voltage divider which will have impedance matched to the impedance of headphones? Any ideas?

Hello,
My first post for home audio. I currently have dual 4-10s made by Tekton. I'd like to high pass these speakers to work from 50hz into a 4ohm load maximum rms by amp 300watts.

The Tekton Design 4-10s have a low pass crossover up to 200hz. So, I'm thinking I could crack open the subs and add a passive high pass from 50hz. That way the subs will be bandpassed from 50hz to 200hz. I'm thinking a 12-24db crossover slope would suffice.

I'm looking for hows to build my own. Parts and diagram if you'd be so gracious to help out?

Overview: I have Tekton Design Ulfberht mains. And I have dual 4-10s which I'd like to bandpass. I'm looking to add dual subs from 50hz and below and is why I am here inquiring on how to passively dual bandwidth the 4-10s.

Much thanks in advance,
William

Looking for a medium-sized tower project to go with my 300B SET amp. Also wondering how the Ceramico's might compare to the Elsinore with the same amp. Room is large-ish about 14 X 18 and music taste runs from folk to jazz to rock. Not into really loud volumes but love the sound of my 300B on current SBA Arya's.

thanks, john

Hello guys,

I modified a MosFET based 100w amplifier, I'd like to know if the resulting simulation is good enough for an actual build. Any thoughts?

Many Thanks!

I'm a DIY Audio newbie after buying a pair of JPW ML-310 speakers on eBay. I've had them apart to check out the drive units and crossovers and and now thinking about what to upgrade. See attached photos.

The crossover is pretty straightforward and I think I will definitely replace those electrolytics for polypropylenes . They've got to be 20 years old apart from anything else!

I am also wondering about making some improvements to the crossover to reduce the baffle step in the response but don't want to do anything until I've got datasheets on the drivers.

The bass-mid appears to be a Peerless unit, KO-100 PL. I can't find a datasheet other than for the KO-100 WFR which has a different frame so not sure it's Thiele parameters and response/impedance curves will the same. Anyone know where I might get a datasheet for the KO-100 PL?

The tweeter looks to be a variant of the Peerless SR-19 DT, which I do have a datasheet for, but the marking on the back (T - 19) isn't what I expect when I compare it to other images of the SR-19 DT on the web. Can anyone definitively identify it?

The cabinets appear well built out of chipboard with the front baffle strengthened with an MDF skin. Isn't that what Wharfedale are shouting about in their latest Diamond range? 😉 There is a decent amount of wadding in there too as well as a rear-facing reflex port. Haven't worked out what it's tuned to yet. Will measure the internal dimensions and port dimensions and plug the numbers into WinISD or Speaker Box Lite to find out!

They sound only just about OK at the moment; the midrange and treble sound a bit congested to me. I'm hoping changing the caps will sort that out. I may also experiment with the value of the tweeter series resistor and/or change it to be an impedance-matching L-pad configuration instead.

Grateful for any thoughts or comments!

Hello,
I have a hifonics saturn amplifier, amplifier is dead,I checked lm494 and there is no pwm signal. I.C has voltage. No decices are blown up in power supply or output, i'm not very familiar with this brand.any help to repair would be greatly appreciated.

Thanks

Looking for the value of SMD resistor in the drive section of the PS.

I believe it to be a 3/4 watt 2010 size SMD.

I believe the non-marine version of the amp is the A6450.

Thanks

I used DN2540 for higher currents, I guess can't use it for this low current so I'm looking for schematic to make a CCS for 1.33mA.

Any suggestion will welcome.

TIA
Felipe

Hey All,


For the past 6 months I've been working on a project to build my own Ultrasonic Vinyl Cleaning machine.



To summarize: it works very well. I bought a 6L Ultrasonic tank, built my own motor assembly for rotating the vinyl in the liquid and piped the tank drainage through a pump and 10inch water filter for filtration.


However, (and this is where I need help), I'm having issues with small 'fibers' in my cleaning liquid after filtration. I've tried a number of different brands and types of filters (also different grades), but I keep having the same problem.

The fibers are very small, you really need to look hard at the liquid to see them, however, they are there and they are numerous. Even using 0.2 micron filters cause the same problem.



Any ideas what is happening? Alternatively, does anyone have a suggested brand / make of filter that I should try?



I live in Europe, so I'm kind of limited by what's available here.


Cheers,



Fish

I've gone through this power amp and replaced the following parts that tested bad:
-the PNP driver transistor tested open and was replaced with an MJE15029. It was already an old NTE replacement when I received it.
-the two 1n914 diodes around it also tested open

I'm getting sound. However it sounds like a very poorly biased transistor. It's fuzzy/spitty sounding with low volume. The volume is only full for a split second when it powers up and powers down.

Where do I look?

I have a scope, but it's packed up. I will get it out if I have to. For now I've got an earphone protected from DC by a 0.1uF cap in order to probe around the circuit and listen to the signal. I have good sound at the output (loaded by R27 -- a 1.5k resistor) with no speaker attached. If I attach the 15" 8 ohm speaker I get the sound described above.

EDIT: to add...
All caps test good (no shorts. electrolytics range up and range down on an ohm meter). All diodes test good. All transistors (including the OP transistors pulled out of circuit) pass a diode test. Rail voltage is correct.

Anybody else do this?
I bought an old hotplate at a yard sale which is essentially some nichrome wire wrapped at about one turn per 1/8" over a 3/16" mandrel. The coil is weaved into the the channels of the ceramic base. I measured the resistance cold - 16ohms. I ran a variac into it to see how much the coil impedance changed over the 75W output of my variac. It increased about 1ohm. It gets hot with 2.5 amps running into into it. Doesn't turn red.
Anyway I think it's a great noiseless 16ohm load to test a power amp at full output swing with.

Hello, I'm trying to repair my PA A3000db. The power supply transistors were all destroyed so I will replace those 16. I checked the resistors in parallel and they are all within tolerance. The output transistors checked out fine except for 2, so I will replace those. Resistors checked out fine.

Two out of the five larger capacitors are bulging at the top, so should I replace all 5?

Also it looks like the black stuff from the outside of all the capacitors melted and got everywhere. Is there any way to remove this?

In general how do you figure out which are the driver transistors? I want to replace them.

Is there anything else I should check before ordering parts?

Thanks for the help.

Hi,

I appended this in Design & Build => Construction Tips, but did not get a reply. Trying here in Loudspeakers => Multi-Way ...

I'd like to try a modification to the Parts Express "Blast box". It would use the same amp (Class D 2.1 Amplifier 2x50W+100W, PE #320-635) and Subwoofer (DCS165-4 6-1/2" #295-198). I'd use a 10" passive radiator instead of an 8". The main enclosure would be ~0.5 cu-ft (14.1 cu-liters).

Rather than two midranges and two tweeters facing forward, I'm planning to use four full-range drivers "magnet to magnet" as with the "b8r".

I have been really impressed with the Tang Band W3-881SJF 3" drivers (#264-911). I was planning to use two ~200 cu-in (3.28 cu-liter) sub-enclosures, each with a center support having four holes and the magnets within 1/8" (3.5mm) of them.

Here are the TS numbers for the Tang Bands:
-Resonant Frequency (Fs) 100Hz
-DC Resistance (Re) 6.6Ω
-Voice Coil Inductance (Le) 0.8mH
-Mechanical Q (Qms) 6.44
-Electromagnetic Q (Qes) 0.41
-Total Q (Qts) 0.39
-Compliance Equivalent Volume (Vas) 0.07ft³
-Mechanical Compliance of Suspension (Cms) 1.32mm/N
-BL Product (BL) 4.47T·m
-Maximum Linear Excursion (Xmax) 0.5mm
-Surface Area of Cone (Sd) 32cm²

I don't know how to calculate the ports on the sub-enclosures. What would be the best way to port them? Any other recommendations?

ANY feedback will be appreciated.

-Mike Mac

I have a number of different chinese SMPS boards, they are very affordable seem to perform well.

I've noticed the description on the pcb's listing 2 output types.
That leads me to believe that the output voltage can be set by changing the value of a resistor on the board.
Or
This is a multi-purpose pcb and the other option on the board requires different components altogether

Is it possible to change the output to 36 or 48 volts by changing resistors?

Just to be clear; there a 2 different smps's in the picture. One is listed as 24V 6A, with 48V 4A as a possible alternative. The other one is 24V 9A, with 36V 7A written on the board as alternative

If it is a matter of changing a resistor or 2, I'd like to know where to start experimenting

Hi,

This might sound daft!!

I've got a pair of Eltax Symphony 6 speakers, to my ears they sound ok/good.
The problem with them is that we have just moved to a smaller house and they are way too big for our sitting room.

Here's my plan...turn them into bookshelf speakers.

The cabinets have 2 speakers, a tweeter and a 6 1/2" bass/midrange and a port. I don't have the spec for either speaker apart from what is printed on the back of each speaker Music Power 150W, Sinus (RMS?) Power 80W.

I've come across several resources which deal with the design and construction of speaker cabinets but all need more in depth specs for the bass/midrange. This I don't have.

A few questions to get me started:

Where do I get the spec from?
Can I do some tests to get the spec I need?
Is there a generic model for people like me!?

Many thanks

Ron

PS I'm a furniture maker so the woodworking side is something I should be able to do.

I have an old AB amplifier, don’t like the sound, its not valuable and it’s out of the rotation. It does have a massive transformer and 64v at the rails. How much power can I get out of a stereo pair of mono class d modules with dsp (subwoofer) 500 watts per channel into 8? 2 ohm stable?...module/design suggestions? General suggestions? Thanks

Got the pair playing in my office today.

Woden Design's Twin EL166 ML-TL (with my own variations). Executed as an MTM with an FF85KeN. We started this one before FF85 was discontinued, you could use your favorite mid-tweeter -- i think Alpair 6M should be a good candidate -- or a tweeter of your choice.

Lots of good well controlled bass. Even thou XO work is still at early stage, i am quite happy with them.





dave

From where I can order a service manual/schematic/wiring diagram of above mentioned car radio cassette ?

Thank you very much.

Some URL's:

Jeep Grand Cherokee Radio Problems — Car Forums at Edmunds.com

Jeep :: ZJ MP3, ...

Alpine Chrysler Car Radio Codes Here

CHRYSLER Car Radio Stereo Audio Wiring Diagram Autoradio Connector Wire Installation Schematic Schema Esquema de Conexiones Stecker Konektor Connecteur Cable Shema | Electrical Wiring | Chrysler

X24C00 smd ALPINE P4704345-F 51T65123W02 or W03 51T45258W02 CHRYSLER Service diagrams free manual schematic download, fix datasheets,programing software eprom bins, repair electronic equipment,help how to disassemble.

https://web.archive.org/web/20060418131505/http://sterr.narod.ru/auto/para.htm
http://www.bimmernut.com/forum/showthread.php/29723-schematic-terrorist-someone-speaks-russian?

Headphone Amplifier
Hello, I recently build Rod Elliot's project 113 (headphone amp, low power speaker amp)
I've tested it on my speakers in series ( I only made one channel to test the schematic) 12ohm, around 2 watts, the sound is gorgeous..
Would putting more BD's in parralel increase power? Or Can I make a darlington design from BD's and some power transistors?
What about swapping the BD's with TIP41/42 for example, or I need some drivers even for the tip's.
At +-18v I can get around 25w which is enough.

I haven't looked at Class D for a few years and wondered about the current state of the art.
Not which amp has the best performance (seems to be the Purifi 1et400 at the moment) but the circuitry and techniques used.
There is a lot of interest in the SMPS world in Zero Volt Switched and similar circuits - of which there is a remarkable number of different variations.
But not all of the SMPS concepts work well as Class D amps.
Is the audio world still stuck on what is essentially a bipolar version of a buck converter?
I notice that at least one tech company has a ~6 MHz 😱 ZVS Class D amplifier for industrial use EPC9065 High Frequency ZVS Class-D Power Amplifier but their audio amp looks quite ordinary.
The specs of the Purifi 1et400 are pretty impressive, does anyone have any information about the circuit?
The switch speed is 500 kHz which is not exceptional, so is the amp essentially similar to the earlier nCore Hypex amps that achieved low distortion from careful feedback loop optimisation?
If so then there's a reasonable case not to bother with expensive SOTA semiconductors or ZVS complications, just stick with silicon MOSFETs.


David

The attached Excel file will show all possible resistor combination that (within a specifiable margin) fits the given/requested/wanted/mystery value.

There is one .xlsx file (no automation) and one .xlsm file (that contains automatic filtering) in the attached .zip archive (but you may not want to run 'foreign' macro's on your system, in that case you need to do the filtering by manual excitation of the keyboard and mouse).

The manual 🙂
1) Set the wanted value in cell A4
2) Set the wanted range (E96, E48, ... E6) in B4
3) Set the precision (margin that makes the calculated value shown) in C4
4) Set the precision (margin that makes the calculated value adored) in C5
5) Goto; Data -> Filter -> Advanced -> List Range = $J$5:$J$774 and then check 'Unique Records Only'
6) Done

Post #8 has an updated version http://www.diyaudio.com/forums/soft...-parallel-resistor-solutions.html#post5008844
Post #9 has the macro-code as text http://www.diyaudio.com/forums/soft...-parallel-resistor-solutions.html#post5008855
Post #15 has the latest version http://www.diyaudio.com/forums/soft...arallel-resistor-solutions-2.html#post5014775

WTB your diy Aleph J or F5 project made in accordance with Mr Pass minimum specifications and genuine parts designation. In the spirit of Mr Pass sharing of his designs with diy community for non commercial use. Prefer West Coast or east of Mississippi due to shipping costs. Please PM me. Thank you.

Hi guys,

First point, I'm french, and I'm not a big user of English Language, so I will try to be the more comprehensive as possible xD

After some reseach, read topic again and again, I will try to make an amplifier with the parts for an old ONKYO SR606.

My goal is to make an amplifier with the specs below

- 2x80/100W under 8R
- Analog input in the beginning
- Get the parts from the ONKYO, but with a LME49811 that I have in stock
- DIY !!
- Use the project linked here for base : Project 8 – BuildAudioAmps

The voltage after the bridge is 2x55/56V. The LME are genuines.
All schematics are on the second post below 🙂

I will use an ESP32 for check the voltage, temp, delay start, and maybe the preamp for a next part.

Concerning the box, I have assembled something with a subwoofer heatsink and some metal parts 😀
A beautiful paint all will be nice 🙂













I created this topic for shared the information, and for find help and solution if I have some question, I hope ^^

Hantek DSO5102P USB 1Gsa/s 100MHz 7'' TFT Digital Oscilloscope 40K 2CH 2Chanel | eBay

Has anyone ever used these? Any input on them? Just looking for something smaller and more modern that the old 465B lol.

Hi there!
I'm Jtore from Italy, I've been passivley using this forum for a bit now, then I decided to sign in and hopefully contribute.

I'm not new to audio or DIY but new to tubes and willing to learn.

I'm addicted to KICAD and sometimes I send my design for production.

I'm sure I will enjoy my time here and want to thank everybody for the useful info anyone can find in here.

Y'all have a great one!

Ciao
Jtore

For those that havnt seen one of these.

LCR-T4 TRANSISTOR/ESR/DIODE/TRIODE TESTER

Got one from Amazon with a case for $40.

Stereophile March 2021 Edition Page 33
Zen Vs ELEKIT TU-8600

Long time no see but back in the day this wasn't allowed wasn't it ?
F4, F5, F6 Aleph and many more from same seller.
BRAND NEW HAND MADE PASS F6 CLASS A AMPLIFIER | eBay

Hi, my name is Chris. I'm here looking for resources for a speaker project.

I have a few older hifonics amps here that have been rebuilt and ready to assemble.

The board supports are missing for these amps .

Wondering if I could possibly use nylon boots and washers to make new supports for the board ?

Asking this since I have no idea on where to buy new ones I’ve searched online and don’t see any like the originals.

Stairway to Heaven- Is the acoustic guitar at the first 2 or 3 minutes on the left or right?

My real question is if channel one is right or left on my dbx 234 crossover?

Hi folks -

Looking for one of these, in good working condition, new or used.

Call me crazy, but I'm trying to avoid the $58 shipping that Hypex is charging me.

I'm currently using Volumio but was curios what others are running.

What is happening these days exceeds anything I've seen before. I knew the stock exchange is mostly decoupled from the real economy, being mostly a speculation playground, but what is happening these days is insane.

Melvin Capital went under the water after being caught in the GameStop crossfire. A $1-5 (according to BofA) stock of a retail company, affected by the malls crisis and the games downloading business, traded up to $380, 600% up since January 12th, whoever was short is FUBAR.

https://www.washingtonpost.com/business/2021/01/27/gamestop-amc-reddit-short-sellers-wallstreetbets/

How Reddit and WallStreetBets blew up GameStop’s stock - Vox

KOSS, EXPR, AMC, FOSL, NOK, CVM, NAKD, maybe others, all stopped from trading, after unbelievable trade volume numbers.

I myself didn't see such a mess since the 2008 disaster. WTF is this going, only God knows, but certainly it doesn't smell kosher.

About 10 years ago I had an itch to do car audio from my former 90s teenage self which all started when my friend gave me a Hifonics Thor X that wasn't working right (in 2010ish). Then almost immediately came a Soundstream MC140x followed by some Rockfords, Orions, Precision Power, etc. There were a lot of broken amps out there and I knew with my highly limited skill and nature to attract 'useless' hobbies that fixing amps would become a 'thing' for me!

That and of course we all owe our spare time in fixing these pesky amps to Perry. - Without him, we'd be treading through Facebook Group mayhem and thinking about landfills and recycle shops piled high with rare car audio amplifies. Thank you Perry, and I hope you are yours are all doing quite well!

The years that followed ~2010 through about 2012 I burned myself out. During that time, the hobby, turned addiction, turned into a side-business. I started fixing amps for stereo shops, and random customers who dropped by etc. Some folks I still talk to, but many others left much to be desired. I didn't have business cards or anything, in fact it was a shoe-string budget business. The spare change made was barely enough to keep a few bucks in my pocket. While it did make me a few thousand bucks (maybe) on maybe about ~100 amps I fixed or attempted. it wasn't worth it in the end.

There were also scarier times where I'd drive around shops, sometimes not even in the best of areas, often finding no work, or loads of junk. I met people who had the amps, but lets just say - many were shade-tree installers. I mean, look at the clientele of your average bass-head is all I should say here. It drove me mad sometimes. I remember one time I fixed a RF amp for $30 bucks and the owner only wanted to give me $10 or nothing. It got a little scary from time to time, and so I stopped doing it all together. I sold all my main gear (Except my Fluke meters) to the 'next' guy.... and then that was that.

Fast forward to the now, and I find myself in a situation where I'd like to re-birth the hobby; but this time in a way in which I can stand for and enjoy it. I don't need the pocket cash, but that doesn't mean I have deep pockets either. No more will I be working on all the junk, nor will I travel to shady shops etc. I'm going to do this for myself, for my own, and be highly selective in what I work on. I'll only look at what I personally call are interesting amps - USA and possibly European only. Any amp that has a company history - or back story will be my desire. Nothing from Asia. No class D unless its an interesting and quality made one (Nothing from Mmats lol). I only want to work on stuff which I would actually use, or something that has useful life for a/my collection or another collector.

Orion
Soundstream
Zed Audio

To name a few.

I'm going to be building my bench test gear, dedicate about a 2x5' space in my shop for electronics repair. I have a nice Weller solder/desoldering station, a Fluke 16, some 12v Pb batteries, charger, and a 14v 40A power supply I pulled from a wrecked camper (BTW thats a good way to find some pretty beefy simple on/off PS units for practically no cost). I'm going to set up this area with some switches, relays, etc to minimize clutter for testing and such. Shelving with spare parts and equipment (which I will purchase as the needs come in based on what the amps need for testing). Basically I'll probably need an Oscilloscope and a frequency generator more than likely. I used to do this out of piles, boxes, baggies, and tool boxes... but now I want to do this with active shelving, parts organization (Or perhaps parts via JIT from places like Mouser etc).

Does anyone have a recommendation for hobbyist setups?

Does anyone have any information on the vintage output transformer manufacturer Electrical Windings company

"<a title="All about our sweet vacuum tubes 🙂" href="forums/tubes-valves/">Tubes / Valves2</a>"

The obvious answer is active device non-linearity, but this is too generic and abstruct. BJTs have an exponential input characteristic, which means, the more current passes through the base, the easier it is to pass more. The output characteristic, that is, the collector current at a constant base current, is not a horizontal line. It is neither a line with a positive gradient, but a curve albeit with small positive gradients. As if these imperfections were not enough, there is also a voltage dependent capacitance formed by both depletion layers at the emitter-base interface and at the base-collector interface. Since, a transistor silicon chip is thin, the emitter-base depletion layer and the base-collector depletion layers are in close proximity, and the electric field at the latter affects the electric field at the former. All these unwanted characteristics of NPN and PNP doped silicon crystals contribute to a transistor operation that is not simply linear, but depends on device voltages and applied frequencies.

Since, this forum is intended for enthusiasts to build their own amplifiers, I would like those who have primarily the understanding of the concepts to comment. The question is how does amplifier topology circumvent these unwanted transistor properties? I would like the discussion to first consider simple three stage amplifiers, differential inputs, VAS and the power stage including its driver.

Please note, I am not asking to repair my amplifier. That, thanks to this forum, specifically, Mooly and mjona and other contributors, still works and is daily filling my home with beautiful music.

Wanted to share this project I designed and built about a year ago.

I wanted to use the GU-17 a very cool tube. It’s the size of a el84 but has two plates and 2 control grids. It’s has only a single cathode and screen grid however.

This means a pentode push pull output stage can be designed with a single bottle. This little guy can make a pretty easy 8w maybe even 10w if pushed hard.

I also used a input transformer on this design. It’s not performing phase splitting duty this time though. Only voltage gain and loading the feedback network.

The driver and phase splitter is a LTP using a 6H8C dual triode.

For the power supply I used a capacitance multiplier for B+ and a simple regulator for the screen supply.

The output transformers I used are vintage units out of a GE receiver. They measure very well.

I’ve included the circuit and the PS as well as some FR/distortion/noise sweeps at 1,6&8w.

This amp also has clip indicating LEDs in the screen circuit. Very interesting to see how loud the amp will play before those light.

Hi all!
I just bought the above 2.1 class D amp. Unfortunately I didn't notice that the subwoofer cut off frequency is set at 180hz. Is there any way I can mod the subwoofer
cut off freq to lower hz?

Do you have a good schematic for a push-pull amplifier using type 50 tubes? I have four of them, and test strong.

So I was revisiting STA540 lately and found out, through manual measuring, that the metal tab of the chip is tied to the stand-by pin. Do I need to isolate the chip from the heatsink if the heatsink is tied to earth (not DC common)?

It is interesting that the datasheet never mentions what the metal tab is tied to.

Hello, I recently designed a power amplifier with capabilities of around 120W. The problem came as I connected the speakers and turned it on. What happened was the speaker started moving and making noise without any input signal. I also measured the voltege between speaker terminals and my multimeter showed the same voltage that was on the positive output of the power supply, sience Im using dual polarity type psu.

I hope someone here has some insight on the topic, it would be really helpful.

orion hcca 150 pop top blowing fuses, open up to look inside i notice power supply fets are all IRF48v but 2, those are 50n06v . it looks like they where all replaced dont know why 2 are 50n06v. any one knows the correct original fets or whats a better upgrade . also notice on the output fets there's a 2n6490 in place of a 2n6491

I'm collecting the sales information for my various posted projects here, going forward. 🙂 This is mainly so folks can buy bare PC boards to DIY if you don't want to lay one out yourself and have it fabricated. The schematic, BOM, and layout of my boards are all posted at the project links below, along with build instructions for each project.

If you need a board, or want to buy an assembled unit, please visit my website: http://www.agdraudio.com/ .

Happy DIY'ing! 🙂

-agdr


OPA1688 Super CMOY project, with the TPS3701DDCT comparator (DIP-6) adapter PC board

Project thread: http://www.diyaudio.com/forums/head...y-2x-9v-real-ground-headphone-relay-pcbs.html


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Inverting Version Of The NwAvGuy O2 Headphone Amplifier project

Project thread: http://www.diyaudio.com/forums/head...avguy-o2-headphone-amp-vs-original-thd-n.html


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O2 Booster Board project

Project thread: http://www.diyaudio.com/forums/headphone-systems/244473-o2-headamp-output-booster-pcb.html


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O2 Desktop Amplifier

Project thread: http://www.diyaudio.com/forums/headphone-systems/229934-version-o2-desktop-amp-oda.html

Hello!
I recently got a non-functional NAD C352, and I plan to use it as a project to get better at electronics and amps.

When turned on, the orange light turns on, but it never turns green. If I’ve understood it correctly, it can’t get out of protection mode(?). I’ve fiddled around with the amp for several hours, but don’t know where to go next. Do any of you wonderful people know where to look? Are there for instance any specific capacitors I can check out which usually causes this problem?

All help is appreciated.

Hello,
I want to build my own USB soundcard for Windows 10 with at least 384kHz/32 bit DAC, like PCM5102 or similar, and for at least 192kHz/24 bit ADC.

Now I have XMOS interface, which only supports output. I like XMOS, it sounds good, it has no noise, it works well with Windows 10, which I am using. But the problem is, that it has no input.

I have module with WM8782 ADC, which is 192kHz/24 bit ADC with I2S output. I don't know how to connect it to my computer. I was searching, I found interface CM6631, but I didn't found any module, which has wired input interface. Only output one. I also found that some guys overclocked it's output to 384kHz/32 bit, but I didn't found any modules or projects, that uses input and output interface. Do you know any? How can I use CM6631 as input?

Second chip I found is CM6635, which supports I2S input and output at 768kHz/32 bit, but I didn't found any datasheet or projects with it. Do you have any informations about this chip?

Thanks.

I have developed a regulator for directly heated tubes that is capable of 1.5A continuous output current. The topology is that of a voltage controlled current source that is high impedance for all but the lowest frequency's of the audio band.



It has a tracking pre-regulator in the negative return consisting of a LM337, this is connected to an adjustable shunt reference and keeps the voltage over the output transistor of the constant current source at a constant voltage.



See the attached images of my prototype, it works flawlessly. The heatsink is a
RAD-A5723/50 STONECOLD AVAILABLE FROM TME.EU





Specs are as follows:



Dropout voltage : 4V worst case scenario
Output voltage : Adjustable between 2.5 and 7.5V higher is possible
output current : 1.5A continuous, about 2A short circuit

Output noise : hard to measure, its below the noise floor of my instruments. There is some popcorn noise on my scope but its low amplitude.

Input voltage : 6.5-30V with no troubles, if the input electrolytic is rated for 35V


Features: Slow start of filaments, thermal overload protection and short circuit proof on a sizeable heat sink up to 7.5V output voltage. The Current source is hard limited to 2A of output current, and the 337 will also limit the current at about the same voltage.



Drawbacks: Higher input-output voltage than some other regulator designs due to the addition of a tracking pre-regulator, you lose about 2V extra due to this addition. But this also means that the LM337 soaks up most of the dissipation at higher input voltages. And gives the benefit of the LM337 internal protection circuitry.



Parts kit contend.

the parts kit will consist of a green ENIG-ROHS board and all the parts pictured on the prototype except the heatsink and m3 stand-offs and to220 thermal silpad. The schematic will be included. And you just have to solder everything yourself. Its all through hole with generous pads so it shouldnt be a problem for anyone who has ever held a soldering iron. One note: the resistors will all be in the same bag so you need a ohms meter or be able to read the color codes for assembly.



price

the cost of one parts kit for one module will be €15. Shipping at current postage rates through POSTNL or DHL whichever is cheapest.



Currently taking firm orders with no down payment, for any questions please ask them here and i will answer them when i have the time.

Hi,

in these days I'm enjoying my 8 Power Cyrus. Great sound, I love this amp so much

Nevertheless, a small problem. I drive it using one of my vintage preamps: a Meridian 101, a Hafler DH-101 and a Quad 33. With any of those sources, the Cyrus' input sensitivity is quite high, so I'm forced to use only a small portion of the volume potentiometer. Nothing serious, but annoying a bit

I've opened the Cyrus cover, and I've seen several links on the board, some with a jumper installed. I am wondering if any of those is intended to set the input sensitivity

Anyone knows something more?

Thanks a lot for the attention, Paolo

I have a gutted but good transformers GT SE-40. The outputs are 1.9K and good for around 40W even though I think that’s optimistic. They have a cathode feedback winding off the secondaries as well as a UL Tap. The B+ is around 475-495V.

I’m soliciting for ideas for finals in a project using sweeps, or something different. I know I can use a pair of KT88 or three EL34, 6L6 per channel, but I’d rather have some fun.

Maybe three 6AV5 in UL per channel?

Thanks for any suggestions and I’m not picky about filament voltage. I can swap out the filament transformer.

Hello

I just bought woo Audio wa 2 and its new, but I'm now experiencing hum/buz when my volume is at clock 11 or higher, my sources are A&K KANN ALPHA and Burson Conductor C3 ref, I have noticed when using KANN ALPHA the Buzz is less noticiable than when using BURSON C3 REF.

any idea what's wrong with my setup, is something to do with the grounding?

I also tried with 2 pins power plug but noise is same and when I touch the WOO WA 2s Chassis I can feel the current I'm assuming the W2 is not properly grounded?

Also whe not using any inputs the Buzz/Hum is almost gone.

Should I buy isolation transformer? Will it help?

Attaching driver board for the above amp. The smd transistors marked DA and BA are bad. Can I replace them with BCX56 and 2SA1416S?

I’m working on a Digital Designs Z2 amp .

Does anyone know of a good part number for the 47mh inductors?

And I know it had been mentioned a few times but I can’t seem to remember the part number for a good replacement for the D1302

Does anyone know ?

Hi guys,

2 questions:
- Does anybody know the capacitor value from the photo?

- Both output driver boards work on one side of the amplifier (creates a PWM), but when plugging them into the other side of the amplifier they does not create an output PWM.

6n137 optocoupler replaced, driver transistors replaced. All resistors read the correct value.
INPUT pins of the driver boards has the correct GND, VCC, PS PWM and output PWM.

Hi,

I am extremely interested in drivers and have printed out every single driver ever produced, but i can't get to grip with Vifas numbering..

Troels hade a sheet but it isn't correct. I found that out when I bought two different models of P17. One was the usual P17, the other one was branded Vifa P17 but the only parts between them were the magnet assembly.

The cone was different, the dust cap was hard and larger, basket was stamped and when I checked it against troels chart, nothing was correct..The magnet should have been bigger and
thinner than P17WJ00-08. It was nothing like the well
known P17 polypropylene cone driver. The cone was a lot stiffer and felt almost like a hard paper cone.

As per the table at Troels site they should be exactly the same in all aspects, which it isn't

Is there any siter on here that has the correct spec sheet and list for what letter/number means what when it comes to Vifa??


By the way,does anybody know how much of the Vifa patented technologies SS got hold of?


Dont get me wrong, SS and Seas are my favorite brands, but If Vifa were in business still, they would be my go to brand asths their extensive driver catalogue was truly superb.

Best wishes, JK

Now off to tune my 23,5hp 69cc track racing scooter( out out over 30hp on the crankcase 😉

Another SS on my bench today. This amp works on the bench for the most part, but here are the previous repairs and also current issues:

Repairs
PS Fets
PS Caps are now XICON 2200uf16v
Right channel using mis-match TIP107 (ST and original mix)
Right channel TIP102 un-touched
Evidence of new driver boards
Q75 and Q76 were replaced or re-soldered using OE parts
Right channel MPSA14 under the board was badly soldered not even sure if all 3 legs were attached

Problems needing addressing
TIP107 in right channel mis-matched - Will replace with sequential ST brand units
ALL the switches sound like garbage and need replacement
At least the gain pots sound like nails on a chalkboard and need replacement
Both 10w snubbers need to be re-attached and secured
General condition of the amp guts is fair. Needs some cleaning and TLC

Again, the amp barely working and since the switches and gains need replacement I pulled the board (Thats when I found the TIP107 mismatch as well)

Question1: On the TIP107s in the right channel. Looks like the previous failure only required about half the TIP107 to be changed (Mismatching now) and did not take out any of the emitter resistors, but of course with the MPSA14 being replaced I'm just hesitant about anything in this area. Should I replace the emitter resistors when I change the TIP107s?

Question2: Should I replace the TIP102 + emitters in the right channel seeing as the TIP107 bank had issues?

Left channel no illnesses, however I know that for the past 10+ years this amp has been used as a sub amp in bridged more.


I'll post more issues as I find things out.

Hi,

The question is simple although maybe a little dumb.

I have a Meanwell LRS200-48V which is a 200W@48v PSU, and I want to power a Sure Electronics Gremlin amp, which is a 400wpc @3ohm, and around 150wpc @8ohm if you want to keep distortion as low as possible...

So... I can use my actual power supply to power it, without a problem, but I think the PSU will be a little bit short of breath in some situations or passage of dynamic music. So... solutions are:

1-. get a more powerful PSU, which are more expensive and hard to get in my country, or

2-. get another identical PSU and wire it in parallel with the one I have.

Is alternative 2 doable or not? Is there any other considerations to look at?

Thanks in advance.

Hi,

I'm still learning about sound, and am hopefully a decent builder.

I'd like to try a modification to the Parts Express "Blast box". It would use the same amp (Class D 2.1 Amplifier 2x50W+100W, PE #320-635) and Subwoofer (DCS165-4 6-1/2" #295-198). I'd use a 10" passive radiator instead of an 8". The main enclosure would be ~0.5 cu-ft (14.1 cu-liters).

Rather than two midranges and two tweeters, I'm planning to use four full-range drivers "magnet to magnet" as with the "b8r".

I have been really impressed with the Tang Band W3-881SJF 3" drivers (#264-911). I was planning to use two ~200 cu-in (3.28 cu-liter) sub-enclosures, each with a center support having four holes and the magnets within 1/8" (3.5mm) of them.

Here are the TS numbers for the Tang Bands:
-Resonant Frequency (Fs) 100Hz
-DC Resistance (Re) 6.6Ω
-Voice Coil Inductance (Le) 0.8mH
-Mechanical Q (Qms) 6.44
-Electromagnetic Q (Qes) 0.41
-Total Q (Qts) 0.39
-Compliance Equivalent Volume (Vas) 0.07ft³
-Mechanical Compliance of Suspension (Cms) 1.32mm/N
-BL Product (BL) 4.47T·m
-Maximum Linear Excursion (Xmax) 0.5mm
-Surface Area of Cone (Sd) 32cm²

What would be the best way to port the sub-enclosures? Any other recommendations?

Thanks, feedback will be appreciated.

-Mike Mac

I just took the voltages from the protection circuit in an NAD 2200, and I'm hoping for an extra set of eyes on a few numbers that I'm scratching my head over.

The one that's most concerning is the -45.5V I'm seeing where there's supposed to be -35V. Thoughts?

I've trying to spin up a new amplifier design--at least 200W into 8 ohms.

My simulation experiments have shown me that the output triple is the way to go, as opposed to the various CFP variations. I am using a diamond buffer like Bob Cordell shows on p. 267 of his 2nd edition book. My outputs are NJW0281 and NJW0302, 4 of each in parallel. My drivers are MJE15032 and MJE15033. My pre-drivers are KSC3503 and KSA1381. All of this is pretty much as Bob suggests.

I've been trying to increase the bandwidth of the output stage from the 20 MHz range, but have been frustrated. The MJE1503x parts were limiting things. I tried substituting an NJW0281/0302 for each of them, and that helped a little.

Then I tried a thing. I replaced the MJE1503x with 3 each of the KSC3503 and KSA1381 wired in parallel. This increased the bandwidth of the output stage by about a FACTOR OF 3! I now have 45 degrees of phase shift at 27 MHz and -3 dB at over 60 MHz. You may ask why I need a 60 MHZ output stage. The answer is that I'm wanting to increase the feedback factor at 20 kHz, and the first way of doing that is moving the 2nd pole further out.

Has anyone else used multiple paralleled KSC3503 and KSA1381 as drivers?

I'm attaching a schematic of the triple output stage.

I simply cannot afford this product I want. I'm wondering if there is anyone I could pay to help me design a clone of this? Or if there is a DIY product on the Forum like this with plans I could build one from? If you scroll down the page you can see a photo with the top off.
DECWARE all tube gain stage / purist preamp model ZSTAGE

Hello to all,

I've been seeing alot of designs using MTM 2 way and TMM 2.5 way .

To those who've experienced both designs , Whether by listening to commercial speakers or DIY ones, What do you think sounds better between the two designs in terms of imaging , soundstaging and detail retrieval, Given than both use similar driver and similar baffle width?

Thank you

I have for sale a pair of PHL 10" high sensitivity mid bass drivers.

Light HiFi use high passed at 100Hz so barely tickled!

Asking £200 plus postage for the pair.

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Greetings. I have a noisy Denon DP 3000 drive unit. The culprit is in the drive circuits and I was hoping someone would have the service manual to share...
Thanks

Hi there,

we're planing to build some amplifiers based on the great concept "LPUHP" originally discussed here: The Wire - Low Power Ultra High Perfromance (LPUHP) 16W Power Amplifier

We plan to add a DC servo to the mix. I attached a schematic of what I have in mind and am looking forward to comments on it, especially if it's feasible to use the upper lead of R207 (normally connected to GND without the servo) to input the feedback signal from the DC servo.

Cheers, Jürgen

Hello, I have a Realistic sta 820 with fm radio signal dilemma. On startup the signal is weak, after 2ish minutes the signal is strong. Fm stereo is working when cold. Any ideas?
Thanks

I'd like to wire up an external on/off switch for my bench speakers for those times when I'm testing an amp that has a DC thump at power on and off. Idea obviously being that I'll switch on the speakers a few seconds after powering on the amp and switch them off right before powering down. (If I had a bench preamp with a speaker switch, I'd be good, but I use an old smartphone as my signal source, feeding it directly into the amp.)

So, I have a DPDT slide switch handy--is there any reason not to connect both the + and - speaker wires through the switch, versus just + or -?

I would like to know the "pecking" order for materials used in film capacitors for audio.
So generally speaking would polypropelyne be better than polyester? as well as metalized compared to non metalized?.
Where do foil and film/foil combinations fit in? Are they better?
I always thought that polystryene was at the top end for materials but now I'm not so sure!!

I know this is a very subjective question, but I read that the "wima" brand is not well regarded in audio so is there a couple of brands that are beter to use in solid state amplifers.
I have used Wima's in the past but have nothing to compare them against.

Good evening guys.

I am hoping someone can help me with a problem?

On Wednesday I totally re-capped my old Cyrus 2 amp. What I did do is change all the caps for non polarized caps. Everything worked fine and sounded great. I then realized that some of the caps are polarized and wanting to keep the unit original I replaced the caps that should be polarized with the correct caps, paying attention to polarity. Since doing this the phono line has stopped working completely, all other inputs are fine. Please can someone guide me in the direction to diagnose the problem.

I am a novice in this area so any help is much appreciated. Thanks so much

Hello everyone,
I'm looking for a speaker construction project of some medium hi-fi quality.
Unfortunately, most of the "troelsgravsen" buildings are not available to me at the moment (I have a wife 🙂
however, I found two projects that interested me:
Daedalus
or:
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do you have any opinion which of the speakers will play better on my PASS A5 in bi-amp mode?
Alternatively, you do not know of any similar FAST / MTW (W) speaker building projects.
My design highlights are:
Jenzen-Illuminator
or
Jenzen-ATS

I’d like to refresh my SE120 by replacing the power supply capacitors, rectifier bridge, and adding an inrush limiter.

I believe the stock DH120 has 6600uF 60V capacitors, and the common upgrade is 22000uF 63V. Should I look to do the same on the SE120?

Mouser has some Kemet 33000uF 63V caps for $19 a piece. They’re cheaper than the 22000’s.