Hiya, I have joined this site, as I am currently learning how to fix audio hi-fi equipment and would love to have access to somewhere like this to ask questions and seek advice as I go about my learning journey!

Dear Forum,

Trying to repair a Powernode N180 with power failure. This is an early generation (second?) of the Bluesound Powernode.

The problem manifests itself by the infamous “red Play/Pause” button. This version has a combined PSU/pre amplifier board.
I have replaced most (large) electrolytic capacitors in the PSU, as these were “bulged”, completely dried out and no capacitance at all.
After the repair and switch on, strangely a small capacitor blew up on the Hypex NC102 power amplifier board. After that all elco’s on the NC102 were also replaced.

At present the Powernode is mostly working again: staring up normally, can be seen from the BluSound app, music can be streamed and headphone output working.
Only the NC102 power is not working. It appeared that +/- 42V power is missing.

It is very hard to debug this failure, as traces on the PSU board cannot be traced on the PSU board. Probably an active element in the switched power supply has failed.

Can someone help me with a schematic diagram of the Bluesound Powernode N180?

(if copyright issues prohibit this, please send me a DM).

Many thanks in advance,
Martin Deisting
The Netherlands (proud Home of Hypex!)

Thought I would share this here, posted elsewhere before, nearing completion now.

I had the tweeters laying around, so I figured I would go for these.
I am using a simplified geometry to make build easier, but keeping angled parts to eliminate standing waves. I modeled it in Solidworks so I could calculate internal volume with all bracing in place (have not done bracing yet). Here is the basic geometry:


Next step, build a little scale model section to make sure everything is going together well, I dont have that much woodworking experience.


So far so good, time to get the wood, got nice sheet of MDF



A few other notes on the build

I am using double thick front panel for rigidity.

Also, these speakers are very very similar to YG acoustics Carmel 2.
The tweeters all almost the same - YG uses scanspeak tweeters custom made for them, with I believe a slight difference.
The woofers are also very similar: Same size, same basket and motor structure. Only difference I see is YG makes machined aluminum cones that they send to scanspeak to be used, while the regular scanspeak drivers use pressed aluminum cones.
Other differences, the waveguide built into the YG speakers, crossover differences, YG have an internal resonation chamber instead of a port to outside, and of course, the YG cabinets are machined aluminum.


Front baffle going well, tweeter flush mount looking all good. I was a bit concerned, never built speakers before, or did a flush mount, but it seems to all be going well.


And woofer hole cut as well, ordering woofers now to test fitment


Woofers arrived


Sexy magnet structure


Test mounted, starting to look like a speaker

G'day Guys,

I am currently designing a PCB for a fairly bog standard phono stage based on the NE5532. Nothing fancy or important here.

The typical way I would handle the power supply would be something like some 7815/7915 regulators on an off board power supply pcb.

Is there a good reason not to put the 7815/7915 regulators right beside the OPamps power supply pins?

Is there a technical reason not to do this?
I can think of cost reasons but it seems to me like putting the regulator right beside the OPamp with the regulator output cap functioning as the OPamp decoupling cap to be superior.

I've modified my beloved commercial speakers; Braun LS200. In fact, these speakers sound decent, at least to me, and they received many positive reviews. But that was about 40 years ago--in the 80s era. If compared to nowadays speakers, they aren't perfect speakers though. They have a lot of cabinet talk. I solved this problem by try reducing mid-bass output from the dual 10" woofers. It was achieved by reducing Q of the woofers' low-pass to allow amplifier to provide more control to the woofers. Then, a slight EQ on the upper high region was added, by means of increasing Q of the low-pass of the 2" dome midrange to gain a couple of SPL there. Finally, the mid-high region was too strong as a result of midrange's mod. Hence, I decrease some duty of tweeters by raising their cut-off frequency a bit. All of these were done with extensively use of simulations on VituixCAD.

For technical detail:
Woofer - the 100uF capacitor was replaced with a lower capacitance of 68uF to lowering mid-bass output and gained lower Q at the same time.
Midrange - the 33uF capacitor on the high-pass section was replaced with lower capacitance of 22uF to flatten frequency response curve that was risen due to the woofers' midrange reproduction. And The 14.7uF capacitor on the low-pass section was replaced with 22uF too to produce more mid-high region for personal preference.
Tweeter - there was an overlap at mid-high region as a result of midrange's mod, the solution was to reduce some duty of tweeter's operating range. Consequently, the 6.8uF capacitor was replaced with 3.9uF.

I need some opinion, analyzing or even criticizing on my modification such as pros and cons, should do and should not do suggestions, although I am already satisfied with it.

Hello, I have a question.

I am designing a push pull audio amplifier with 2SK1058 and 2SJ162 mosfets.

Normally they are used with a 0.22Ω source resistors.

What about to put these 0.22Ω resistors connected to the drain?

Thanks

I've bought a laptop cooler to use with a pair of Fosi class D monos without realising that it was USB powered. Is it possible to somehow convert this to an AC plug connection?

Hello Everyone,

I'm looking for power distribution body/box, where I can put 5 – 6 Schuko outlets of Furutech FT-SWS or FT-SDS. I need either finished products, or place where can make specific size. The body I need is very high quality: thick, solid, heavy, and stable. To insure stability and minimize vibrations.

Anyone know, and what best material used (Aluminum, Extrude Aluminum, Steel … )?


Thanks so much.

Hello everyone,

Im looking to sell some Ian canada stuff
1. Fifopi Q7- $140- sold
2. Fifopi Q3-$80
3. Reclockpi - $30
4. Scpure clock 45.158 mhz - $130- sold
5. Hdmipi Pro - $70
7. 2 ucconditioner 5v with ultracap - sold
8. 2 ucconditioner 3.3v with ultracap- sold
9. uconditioner 5v- 60 each
10. Unconditioner 5v- 60 each
11. unconditioner 3.3v - 60 each
12. Unconditioner 3.3v - sold
13. Transportpi - sold

Pictures to follow

Buyer pays shipping and paypal fees.

Thanks

Hi,

Up for sale is crown xls 1002 amplifier. Barely used.

Buyer pays shipping and PayPal fees

Asking $250 or best offer.

Pictures to follow.

Thanks

TI continues to surprise us with top notch products. After the OPA1656 I 'discovered' the OPA1637. A fully differential amplifier with excellent audio specs.
Ordered the eval module to get a head start*. I can see several places where this would fit very well, like fully balanced post-DAC filtering and/or I/V conversion, fully balanced preamps, fully balanced active filters/xovers. And, my own target, an improved fully balanced AutoRanger.

Anybody here with similar ideas?

Jan

*If the international shipping system holds up, hopefully.

Hello All,

I'm trying to change the Bluetooth pairing name on my QCC3034 Bluetooth chip. This chip is integrated into the Amplifier board im using on my project (Wondom JAB5). I was told by Wondom that I can accomplish this by using the Qualcomm TRBI200 via QCC_Tool. I purchased the TRBI200, downloaded the latest version of BlueSuite which comes with the latest drivers for the TRBI and can get my computer to recognize it. The problem im having is that BlueSuite and QCC_Tool does not recognize it or detect it. Am I missing something here? Do I need any additional steps to activate the TRBI so that it can be detected by the Qualcomm software? I created the key file and unlocked it as well, but does not help. fyi, I'm using the MOSI, MISO, CLK, +3.3v, GND pins for this. I'm also using Windows 10.

Any suggestions will help, thanks in advance!

hi i am having trouble connecting to win 11 - i swapped the cable and seamed to be sorted - turned dac power off last night and it gone again - any help please

Hello. I'm from New Jersey, USA. Have been an electronics experimenter since a child in the 1970's, and building/repairing audio equipment since then too. My nickname Kolchak comes from the 1974 TV series Kolchak The Night Stalker, hard to believe it premiered 50 years ago! Time flies! I remember when our local electronics store, had rows of vacuum tubes behind the counter!

Kind Regards - Kolchak

I’m looking for a very basic, intro type book on circuits, I mean absolute beginners guide. I have no electronics background so what most on here would consider basic is probably not to me.

I’m faking my way through things by being careful and following instructions but it’s just not very smart doing it this way.

Greetings everyone!

I am a new member and I am looking for help. 🙂

I have a helmet bluetooth intercom using the QCC3024 IC, unfortunately the IC got burned due to over charging. Can I just replace the QCC3024 IC and the intercom will work again? Or it needs some sort of programming for it to work?

Thanks in advance.

Great vintage DAC based on DPA's discrete 1-bit current-pulse convertor.

Faceplate in good condition for its age, casework a bit scratched sadly. Most importantly all working and sounds very good.

Coaxial RCA and Toslink inout. 1 x RCA phono output.

Pics to follow soon when better light available.

Will sell for £225 inc. UK postage given cosmetic condition.

Collection from Edinburgh possible.

Thanks

Eastone

Hi.

I just found this forum because i opened up mijn ADAM Sub 8 because it is dead. And i googled pictures of the boards inside and found a recent topic.
I repair for myself some old stuff. Synths, drumcomputers, R2R, just some basic soldering etc.
See you around 🙂

I would like to share my blog post where I do a full test with measurements on the CHR120 along with subjective listening impressions. The cabinet is 28 liter tuned to 40Hz.

https://josephcrowe.com/blogs/news/markaudio-chr120

I wanted to embark on a build of a Frugel Horn XL but the donation link here: https://www.frugal-horn.com/FHXL.html doesn't work. Is there another way to get these plans?

Folks,

I've started my Pass Labs journey with the purchase of a X150.8 power amp earlier this month. The reason for this post is that I've had a BAT system comprised of a VK-55SE tube amp and a VK-80 tube preamp. It was a great system-open rich holographic. Fast forwarding I still have the tube preamp which is driving the X150.8 (driving Zu Def. 3 speakers). However, presentation seems veiled, loss of texture, detail of instruments and voice, and note decay. What it does bring over the old system is rock solid expanded space (wide and deep) and much better localization than previous set-up. Per a friend's advice who owns a X350.8 mated with a XP-22, I was advised to let it break-in a week or two. At this point not much of an improvement.

So the ultimate question is it a break-in issue, component mismatch, or some other issue that may be causing the issue? My earlier research based on impedances pushed me towards "no issues" since the X150.8 has 100k input impedance, while the preamp is at 300 ohms.

My ultimate objective is to have an entire Pass system to replace my original tube system (having equal or better SQ). However, I was hoping that would be later than sooner due to the investment just made. Anyway, just doing a sanity check.

Many thanks.

Neil

I searched through a lot of thread here and did not find anyone building an Onken cabinet with two drivers.
Has anyone done sims or built one?
I am thinking of 2 12's, does this effectively double the size of the cabinet?

Looking for a compact pcb for a 70033k transformer footprint and basic regulator, does such a thing exist?

I have a Panasonic RS-280S receiver that I'm working on restoring. Link with pics of this receiver: https://www.hifiengine.com/manual_library/panasonic/rs-820s.shtml . Everything works on it except the light bulbs and the meters showing the output to each speaker. Where can I get all new bulbs and meters for this receiver? How do I replace them, anybody with previous experience?

Hi,

Does anyone know of any devices to replace the CS8422 now that it is discontinued?

Thanks,
G

We are currently developing hi-fi MC cartridges.You are welcome to come to us for customized cartridges!

We can accept MC vinyl cartridge customization, such as different types of needle bar customization, different voltage output customization, etc., individual appearance customization, etc.

Depending on the configuration, the price is also different. Interested friends can take a look at the samples in our store first. Of course, the price for bulk orders will be lower than the retail price.

https://www.ebay.com/itm/204703055422
https://www.ebay.com/itm/204571396117

Picked up a Akai M8 I plan to restore that touts having "cross field heads". Looks like this is just for recording and am curious how well this works. TIA

Hi everyone,

Many music recordings are normalized such that the largest samples are full-scale, but after interpolation, the signal then usually has to exceed full scale. This often makes digital interpolation filters go into hard clipping, as they are rarely designed to handle this. The recording itself is not clipped, but it makes an interpolation filter without headroom clip. Benchmark Media has dubbed this intersample overs, and found that some recordings have hundreds of intersample overs, see https://benchmarkmedia.com/blogs/application_notes/intersample-overs-in-cd-recordings

When you use a digital volume control, it depends on the exact implementation whether it solves the issue. If the volume control is done before any digital filter and if it is set a few decibels or more below maximum volume, then there is no problem. If the signal first passes through an interpolation filter with no headroom and then through the volume control, reducing volume won't help.

At the end of a now-closed thread, @jean-paul asked me to compile a list of DACs with and without intersample overshoot issues. Unfortunately it will be a very short list, because I have no information about most of them.

Some four years ago, I made a test signal that makes it very easy to determine whether a DAC has or hasn't headroom for intersample overs. It consists of two high-pitched sine waves that produce very audible intermodulation products in a DAC that clips on intersample overs. The test signal and an explanation (in English and Dutch) can be found in the attached zip file. There are two other audio files, depending on whether there is an issue, the test file will either sound like one or the other.

Could everyone who wants to participate play the test signal over their DAC with the digital volume control at maximum and a bit lower than maximum, compare the sound to the other two files and report the result and the DAC or DAC chip model? I will then add the results to the list. To prevent blowing up your ears and your tweeters, the volume should not be too high, so don't do the test if there is no way to control the volume on the analogue side.

Thanks in advance,
Marcel

P.S.: when you play it from a computer, you have to make sure somehow that the computer doesn't change the volume and doesn't do any sample rate conversion, otherwise you might be testing your operating system instead of your DAC.

Lists:
DAC or DAC chip model: clips on intersample overs at full digital volume; clips on intersample overs at reduced digital volume setting (if applicable)
Valve DAC of Linear Audio vol. 13: no; no (the only digital gain settings are 0, -6 and -12 dB)
Typical NOS DAC: no; not applicable
AKM AK449x DACs with the exception of AK4495: probably; no
Gustard X16 (ES9068AS): yes; no (-2 dB)
ES9039Q2M (bohrok2610's DAC): yes; no (-1.5 dB)

Sample rate converter model: clips on intersample overs at full digital volume; clips on intersample overs at reduced digital volume setting (if applicable)
Foobar2000 with RetroArch (resampling to 176.4 kHz): yes; no (-2 dB)
Texas Instruments SRC4392: yes; probably

It should be noted that sample rate converters that have essentially the same fixed-point number ranges at input and output cannot have 0 dB gain without intersample over problems, at least not when they are interpolating.

I learned about it via mention from another player at the open mic last Friday. He then played a song in tribute. I changed up one of my three to "jack straw", which I played with all the finesse of a bulldozer clearing a patch of land. Someone later told me he hadnt heard that in 20 years, so I must've rendered it in at least recognizable form, for Phil.

Saw a video discussion on YT with Phil. He's an audio guy; they talked of the Wall of Sound, how the mics worked and he even knew what the capsules used were for and why that didnt serve so well for vocals. He said his bass had an individual output for each string, but he never used it "too confusing",

I've also read his book "Searching for the Sound".

RIP Phil

Thank you for this forum. I had been active on another foum modifying an LKS DAC. I've moved beyond that particular DAC and its streamer and am now looking here, especially for ethernet to I2S streaming. Like many before I've been introduced to Iancanads through the Gabster videos.

As per the title. Nowt else to say!
£30 plus post

my attemps werent succesfull and i also dont own an big enough heatsink and an transformer to complete it as is, by attempts i meant copy-ing the circuit into ltspice and changing the values, i also didnt have enough time.

A pair of these for sale. I haven't personally used them but they have signs of being soldered. Otherwise mint. Measure 6.6ohms DCR.
£30 plus post

4 of these nice aluminium coned drivers. All unused. All measure approx 7.8ohms DCR.

£25 per pair of £40 for them all plus postage.

Hello everybody,
i'm new here. here for a specific thing and hope to expend my knowladge.

Reagrd from the otherside.

What pair of BJT recommend me for single ended class A emitter follower on 16 ohm load?
Input 10 volt max, 0.5A max, best flat transfer curve possible (and possibly sound).

Many thanks!

Hello,

I'm excited about having joined diyaudio. I'm very much looking forward to improving my diy skills and to contribute to the community where I can.
I did build some speakers from soundblab and now I started to create and calculate my very own projects.
The first was a very cheap TL with the fabulous Markaudio CHR70. I'm about to finish the filters.

Cheers
Roesel

Post your favourites throughout the year in here. I'll start with EMF and their new album The Beauty and the Chaos

https://rateyourmusic.com/release/album/emf/the-beauty-and-the-chaos/

I am going to try and document the configurations and setting I am making on a fresh win 11 install to reach the goals of the title. If possible.

1. first thing I am left shifting the task bar and un combining taskbar icons and labels. This setting is under taskbar behavior.
2. Uninstalling bloat ware.
so I just searched for programs and features and was forwarded to apps/installed apps and was able to uninstall a lot of things that I do not need. I have a suspition that this is the short list of installed apps and that I will have to use powershell to get an actual appx list but that is in the future if needed.

3. Should have been first but using advanced system settings, select best performance and then re place the check mark for show thumbnails. the advanced system settings are in settings / system / about.
4. Oh my! what can be done about the start menu? I'm searching now.
wasn't so bad used personalization / start to get more pins and turn off some recommendations.

5. Just found other software hidden in system components game bar / phone link ect. Will try and uninstall some things without power shell for now.

6. no update today except to ask how some of the responders think that they can talk an office manager into paying me hundreds of units of money to put a different start menu on the office workstations. One person in this or the computer thread suggested that the employees should get different jobs because of the operating system.
Again my point for this is to get the best out of it not replace it.

Sorry for the rant, so things bled over from the computer thread

9-10-24 6PM gmt-5
7. open up task manager and turn off auto startup for one drive and edge (I suspect that this will be turned back on by updates.)

8. go to settings / accounts / your profile and switch to "sign in with local account"

9. update powershell help
update-help
run this in powershell as admin
Get-AppxPackage > c:\list
open c:\list with notepad
find the packages that you don't want but remember if you don't know what it is then ignore it for now

As a goof I ran" Get-AppxPackage -Name xbox | Remove-AppxPackage" to remove packages with xbox in the name and I removed "your.Phone" I will let you the repercussions.

9.001.
I have installed 10 on another machine and let it upgrade to 11 so that I have a base line. This base line machine will not be modified beyond personalization settings.

I am setting this base line PC because I am starting to think that it is fine for the common user with little more than letting onedrive run but don't sync your folders other than the default one drive folder, installing a preferred web browser and turning of suggestions.

I’m here to absorb information and apply that in a Sibelius build. So it will be different from the original, but I don’t know which of my ideas are feasible or beneficial for the result

How's that for an intro? I was introduced to this sport of "buy and hope 'they' don't find out" by a well experienced friend who didn't know when to quit and now owns an entire good sized pole barn full of any type of audio equipment we could dream up. I currently own two stereo sets myself, including a pair of AR bookshelf-sized speakers. I have components and plans to build a pair of La Scalla style of speakers. Also have a Panasonic RS-280S receiver that I'm working on restoring. Link with pics of this receiver: https://www.hifiengine.com/manual_library/panasonic/rs-820s.shtml I'm not sure if I should start a new post on these projects somewhere else on the site or can they be discussed on this thread? Things I want to know on these projects: Where can I get all new bulbs and meters for this receiver since they of course all burned out? How much is this thing actually worth if I sold it, like will it be worth my time restoring it? Where could I get build plans for my speakers?

Hi guys, I'm new hear.

Im in no way an electronics expert, but i do dabble swapping out faulty capacitors in power supplies, and faulty pots in amps etc.

So i have a few QSC RMS 2450 amplifiers. Only one of them has this strange issue.

When i turn it off, after a few seconds, the clip lights light up and distorted audio can be heard. After maybe 6 seconds of this, the clip lights go out and none distorted/ clear audio can be heard. I can even turn the volume pots up and down and it controls this audio as if the amp is still on, although it's not putting out the same sort of volume as when the amp is on.

This will carry on for maybe 30 seconds or so, untill the amp completely goes off and silent.

I'm guessing it's something to do with discharging of capacitors, but can anyone explain why this is happening, why this is the only one of maybe 8 of these amps I've had over the years and how i fix / solve it? Thanks

Hi,
Can anyone suggest a decent 845 SET amp either in Kit or made within 1500$ range?

New here but have been on similar forums for awhile. Here to see what’s different and learn a thing or two.
Best,
Mark

All items in perfect condition and most unused, collected over years. I think AVID mostly. Various sizes.

£15 for everything plus shipping.

When I measure my Markaudio Alpair 10.2 TQWT speakers separately at the listening position I see no dip around 100Hz, but when I measure both speakers at the same time (orange) a wide dip occurs at 100Hz. It seems as if both waves at the listening position get out of phase at 100Hz. I have the same effect with Harbeth P3 speakers. Does anyone understand this effect and how it can be corrected?

Just interested in people's opinions on this.

Hi
Does anyone happen to have the service manual of the AP "Portable One Plus"?
Can't find it online and AP wouldn't provide it 🙁

Original source is here, just to make it clear that these are not my designs. Since i don't speak bulgarian, i can't ask anything about the design so its far easier to post it here. Quite fancy building this design as i've always fancied a quad. (did look at the 405 designs too) I am not certain whether I can substitute the 2SA1837 toshiba parts out for something like sanken 2SA1859A. It also suggests using ZTX552 for T5 which i can't find and ZTX752 for T6 which i've substituted for ZTX753. Are the MJL21194 main outputs the best or is there a better part. (the parts list i have differs from the parts on the schematic)

Last of all, the power supply design that i was intending to use was a 2x 50V 625VA toroid with 2 rectifiers filtered by 4 22,000uF caps. I noticed that the original 909 psu has some additional components and the +/- rails are offset. (+57.8V and -53.4V)

Schematic. I also have the Eagle design files with both schematic & pcb.


PCB

Hi All 🙂

Long term lurker from India. Have had some decent speakers from the likes of PMC in the past. However, looking for a change as we all do, I ended up getting a pair of 3 way DIY speakers built with the SB Acoustics Satori. These have startled me, in a most pleasant way. And now I cant stop looking for the next big idea.

I must admit that, at this point in time, Iam driven by enthusiasm rather than dry science. And I've probably dived at the deep end of the pool in my first attempt to swim, by purchasing the drivers for my first OB build.

Looking forward to reading and learning and sounding out my duff ideas against the combined wisdom of the forum. Thanks for having me here 🙂

Thanks and best regards
newlash09

Not audio... but the Fox audio was in stereo...

Shades of Kirk Gibson with that walk off homerun...

BUT, last night, THAT was a Walk Off Grand Slam.

Wow. An instant classic.

Your team is down by one.
Bottom of the 10th.
Bases loaded.
Two Out.
It's Do or Die.
First pitch.... adios! Way over the Golden State Fwy.

Hello

New member here. Im interested in hifi, music on cds, 2 channel audio. Recently ive changed old amplifier to balanced circuit amp. Hope i will find some interesting stuff on this forum.

Greets Newman

Hello!

I'm a life long audio enthusiast and obsessive tinkerer. I started by taking apart my uncle's old HAM radios just to see what was inside. If only I had a few of those gems around now! I do however have a pretty large collection of pro and semi-pro recording gear in my studio, as well as quite a few home hifi systems and odds and ends. I'm the guy everyone brings their broken or unwanted stuff to. I try to pick through it all and these days about 60 or 70% of the time I'm actually able to render it useful (at least to me)! No matter what, I always learn something new when I tear down a piece of equipment. But alas, surplus audio gear is a bit like a homeless pet: try as I might, regretfully I can't save them all.

Looking forward to getting and possibly contributing some great advice to the experts on this forum.

Thanks,
Ryan Freeman

Hi, everyone! I'm a Hi-Fi Audio hobbyist from time to time (due to other interests in my life) since about 14 yrs old. This forum seems to be the most informative and having proficient experts which I've been learning a lot from.

I changed a 75W bulb into a 20W Led bulb.
At nigth i notized the bulb glows faintly, but clearly visible through the milkglass cover (its a lamp outside my front door) even it is not switched on.
I suspected leakage from a faulty switch or cable.
But leakage resisistance was unmeasurable high.
Next i measured the current, 4 uA !
Gotta be capacitive coupling, i have no other explanation, less than 100pF seem to be enough for that bulb, truely amazing

Hi, i am really interested in learning Audio transducer design but do not know where to start. I have knowledge in building speaker enclosures now i want to learn designing and simulating the driver it self. If any one of you can help me with the subject please suggest me a way that helps learn audio transducer designing.
Thank you

Hi again 🙂

Ok, I know that there are numerous threads on 601 tweeters, but I'm now looking at 'near-equivalent' replacements, and wondering if anyone has tried any?

My pair of B&W 601 (the original - I guess S1?) are suffering from the typical defunct tweeters - both of them. I knew this when I bought them - I got them cheap for that reason. I fancied the challenge of fitting new dome-coils, but that isn't turning out too well even tho' I figured I positioned them spot-on... I also topped up the ferrofluid - perhaps too much?! Interestingly, the tiny feed wires on mine look as tho' they were vaporised - someone must have driven them hard.

Anyhoo, whilst I keep experimenting with a tweeter repair, I'm also looking at other options such as a near-equivalent replacement. I am not concerned about the physical aspect of the installation as I'm reasonably confident I can tackle any mods required, but just that it is a close audio spec match to the original. There must be hundreds of folk looking for this, as these superb speakers are failing almost always due to their obviously-delicate tweeters.

I don't think there's any mileage in buying 'genuine' second-hand replacements, as their lives will be of an unknown span. Brand new (say S2 or S3) B&W tweets are silly money, so again are out of the equation as these are old speakers that barely justify this. So, that leaves either a successful 'repair', or an equivalent fit.

Sooooo, any ideas folks? Someone must have tried this?! Or am I going to have to be the first?! I've read they 'cross-over' at around 4kHz and are 4 ohm resistance, so surely any decent quality tweeter of that near-spec will work well?

So, any ideas on near-equivalent tweeters? 🙂

Thanks.

Hello guys, my name is Graham 2439. I've just inherited a Marantz CD273 Special Edition CD player - no extras, manual etc.
The item seems to be working - all lights and buttons live. I have hooked it up to a pair of old Wharfdale speakers and I can faintly hear that it's working, but there is no volume and it appears no control on the player. QUESTION: do I need an amplifier and if so could someone tell me what I should be looking for?
Many thanks for any help

I just finished working on a PA-2400. Recapped it and replaced the carbon film resistors in the signal path with metal film. The amp was in good working condition prior to the work. The distortion I measure before and after are very similar. The spec quoted by H/K is:


When I measure 1kHz @ 1 Watt I get higher distortion:


When I measure at ~72Watts distortion numbers are better:


Do you think this is normal for a PA-2400? Does anyone happen to have one?

In general, what would cause the harmonics? The amp sounds great to me, and I don't want to go chasing a problem that isn't a problem.

Wuzhi Audio markasından bir Çin amfisi aldım ve hatta 150 W aldım. Benim sorunum Bluetooth veya AUX ile bağlandığımda müzik sesi cihazların gövdesinden geliyor. Hoparlör bağlasam da bağlamasam da.

Translated I bought a Chinese amplifier from Wuzhi Audio brand and even got 150W. My problem is that when I connect via Bluetooth or AUX, the music sound comes from the body of the devices. Whether I connect speakers or not

Hi. I am new here in the forum. I am planning to build my first tube preamplifier pair with my solid-state power amplifier. I am not a circuit designer, and I am not so good at technical stuff, but I have done a few DIY amplifier assemblies by myself with the help of schemes. So I am open to suggestions of a well-made pre amplifier board/kit to start my work. Because I can't work an amp from scratch, a preamp kit will be a nice option.

When I was going through many posts here in the forum, I was a bit confused by the lot of preamp boards.I want to learn and upgrade little by little to understand the sound. That's why I am planning a DIY path. I don't know if I can do this with my zero knowledge, but I am very much willing to build one.

I hope you all can guide me. Thank you so much 🙏.

I'm planning a 6GV8 headphone amp using current source loading on the triode stage, and wondering about an appropriate output transformer. Rails will likely be around 200VDC. I'll probably be driving Something similar to an Audio Technica M60-XA. I'll likely be shooting for 10X gain, closing the loop around the XFMR.

I hate to admit it but I bought too much. Below are all my overstock of transistors from my early days of through-hole building and repair. They are well counted and organized as in the pictures but only of use, to those who know how to. That's you guys 🙂

$40 +$7.52 shipping in the lower 48

Hi,

has anybody the design of the crossover?

I know they use the TN-1 dividing network but i dont know how they do it.

Thanks for your help.

Josef

Hello. I have a Yamaha RX-v373 receiver that seems like it may have the DSP issue. Diagnostic mode shows no error in the Ti reporting in or check-sum. All speakers and such work in diagnostic/bypass mode. Normal power up results in no sound, "cinemaDSP" indicator shows on screen but speaker indicators do not. This exists in all profiles. All relays seem to be clicking normally with the possible exception of the final speaker relay.
I had left the receiver on for a day or more after using for dvd's one night. It seemed to work fine immediately after I found it, but the next time I tried it resulted in the no-sound condition.
Any thoughts on whether this is or is not the DSP? Or is there some other circuit I need to check? I have the PDF of the V373 service manual so I can reference from that for specifics.

Hi there, just acquired a Cambridge Audio edge W amp. Looking at images on the net it looks like the top is held on by quick release fasteners. Anyone know how to take the top off?
Thanks

Simon

Good morning,
I' m interested in building a dedicated PC for only transport purposes, to play files and send via USB to an external (high-end) dac.

I looked to many implementations, with expensive LPS, 2 or 3 cases for power supply.....BUT at the end every motherboard has onboard VRM for low voltage regulations 1,8V, 3,3V, 5,V...
and these regulators are 100% switching
LPS to power the mobo, the cpu, the hard disk is completely useless, if the voltage regulators onboard on the MOBO produce for example 100mV ripple!

my question is:
How to choose a MOBO in order to have the best VRM and the lowest ripple?

there was a past topic now closed:

I ask for example @skibum @geraldfryjr @marce if they can help, thanks

​

Hello all,

New member here. I have replaced boards on several GFA-565 amps now and I had a peculiar issue on one of them. The board worked fine for about a month or so, and then the unit came back to me with the user complaining that it was running hot - really hot. I checked the bias and it was way off - inexplicably so. I adjusted the bias to the limit but couldn't bring it back into spec.

For background, I'm still using the "older" BFA-565 boards and not the updated EBFA-565 - this particular board was done about 2 years ago; adjusting the bias to the limit and telling the user to turn off the amp while not in use was an acceptable solution, but he wanted a complete fix that I didn't have the time for then, but I finally got the time now.

I went through both output blocks and everything tested out correctly. I then went back to the main board and re-tested all voltage points. Most everything tested within spec except that the bias voltage range (reference his linked spreadsheet on his site: https://www.dropbox.com/s/kr8w2nrcx...85 Input board performance checklist.xls?dl=0) is about .05v out of spec and about .1v from where it was when this particular board was installed. I highly suspect that this is the root cause of the bias jumping. However, I have no idea what the root cause of this "jump" was. I could simply change out the two resistors (R141 and R162) until I'm able to get the bias adjustment into an acceptable range. This is not an ideal solution as I'm worried that I may just be wallpapering over a potentially larger issue. I would much prefer to get at the root cause of this bias jump.

Any help would be greatly appreciated. My electrical engineering background is primarily in high-speed digital signals with minimal exposure to power electronic circuits (and I'm 25+ years removed from school at this point) so I'm a bit unsure of exactly how the biasing circuit is supposed to work.

I am selling used vinyl records in very good condition, both the cover and medium. All of them were purchased new, handled carefully and stored properly. The linked spreadsheet contains details and, whenever available, a link to the corresponding entry in the MusicBrainz database. The price is in the last column.

Payment via Zelle.

SOLD!

Hi, want to buy a ready to go (assembled and tested in chassis)linear power supply for 12vdc 3A dac.
5.5/2.5mm center positive pin.
Mains is 230 50hz(Europe)
Thanx

Hi all!

I’m tuning the active crossover (CamillaDSP running on a Pi) in my 4-way system with side-firing woofers, and I’m having a hard time understanding one issue.

My listening position is about 2.7 meters away from the speakers, and my ears are at the same level as the mid-dome. This puts my ears approximately 2.975 meters from the side-firing woofers.



If there is no delay configured in CDSP between the woofers and the other three drivers, I observe a significant dip at the crossover frequency (around 125 Hz), which makes sense to me (blue line). Based on my calculations, assuming the speed of sound is 343 mm/ms, the sound from the woofers will reach my ears about 0.8 ms later than the sound from the other drivers. So, I added a delay of 0.8 ms to the other drivers (green line), and while there was some improvement, it didn’t fully achieve the expected summation of the individual drivers' measurements.

I then experimented with several different delay values, taking measurements after each adjustment, and found that a delay of 2.5 ms gives me a response (yellow line) that accurately reflects the summation of the woofer and midbass response.



What I’m trying to understand is: Why is there a difference between the measured results and the math?

Hi everyone

I just joined this forum, where I saw lots of interesting posts on amp with STK circuits repair.
I have 2 non-working Technics SU-V2 amps (link for service manual here : Technics manuals | Hifi Manuals Free: page 5) that I want to repair.
Both have faulty STK8040, so I intend to replace them wih discrete components such as those described in another thread of the forum.
But prior to that, I have to make sure the rest of the electronics is OK ... and I need help for that.

To start with, amp #1 : both STKs (IC301 and IC302) are dead, and so is tone controller op amp (IC303) => I removed those 3 circuits and tested all measurements points in the ”pre-STK" amp section (transistors Q301 to Q318 area) as mentioned on the schematics.
I found out some differences with nominal values : are voltages supposed to be the same as indicated on the schematics or does the removal of the 3 ICs have an impact on their values ? If so, which values should I expect ?

Thanks for your help

Hello all, I want to build a two way speakers for a room in which we makes party with friends.
I want excellent sound, but with low cost speakers and probably this will be a difficult mission and for that i want help from you. I decided this year to make two two way speakers and next year will add a subwoofer probably one big 18 inch Precision Devices PD-1851 or BMS 18N862 , but no budget for them now.

For woofer my budget is 100-130 euro and i prefer to be 10 inch because no more space for bigger driver/box.
For CD i hope to fit in around 50 -60 euro
I searching for low cost woofers with high performance, to get maximum DB and i find LaVoce WAF102.50 which give me 119db in 25 liters box with 150 watts signal by WinISD.
For CD I see that have many cheap options but which is better i don't know, I also check here in the forum, but that what i find is mostly more expensive like BMS 4550 and B&C DE250 and try to find second hand BMS 4550, but i cant find used in my country,and i hope you guys to help me to choice best value for the money. I also see in the LaVoce brand very nice curve of the LaVoce DF10.144LK at price which is in my budget but i'm not sure will be ok or not for this woofer or you will suggest me some other woofer which will sound better.
Please give suggestion for excellent sound 10 inch woofer and CD 🙏
-------------------------------------------------------------------------
I have also 2 tweeter SEAS 27TDFC, but im not sure if they would be suitable for a high performance 10 inch pro driver.

This is a Chinese supply from Ali, I saw that the parts are be not readable, and repair
difficult.

No, it is not, the driver ic is the L6599ad I think. based on the outputs to the mosfets
who fit. But maybe it is with all L 65 series that way, so I need to remove the small pcb.

I see it has feedback, and as such also burst mode, this is not something a amp is happy with.

Idea was remove the feedback and set the frequency to resonant point or just above it,
now afraid to enter capacitieve mode, because the frequency will be fixed, but do just above
resonance for shure. this point make it possible the supply act the same as with a 50 Hz big Elco
supply.

Hi. I'll make myself a pcb for the B1-Nutube, check the picture. Since it seems to be usefull for some other members, I open this small GB.

It is the Firstwatt circuit, with optional on board power supply using a Meanwell AC/DC 24V converter and additional CLC filtering (smd parts), before the original B1 CRC filtering. There are pads on the board to still connect an external dc power supply if you wish so. It still supports 2 inputs and two separate volume pots.
The AC/DC Meanwell power module MPM-20-24 is good from 80 VAC to 264 VAC, so good around the world... The PCB size fits the Hammond 1455N2201 chassis.

The PCB has a generous ground plane as the original FirstWatt, the AC section is located in the left corner, the audio in/out on the right, well separated. Each channel trace is separated by a ground (shield) trace. The input traces are routed from the bottom, the output from the top...

The PCB will come with the complete BOM, parts silkscreen and schematic.

Please right down your name and quantity. This small GB won't be open for long, so act rapidly. I'm almost done with the pcb desing. Cost should be 20U$ + Paypal fee and shipping cost to you. We should be good for at least 5 pcb. Will try to place the order in the next 1-2 weeks.

I'll keep you posted. Thanks
SB

20 Feb Update: Now reaching for QTY: 15, price will be around 16U$ then...

Hello Everyone.

This may sound like a newbie question, but I don't want to blow-up the P50, so I ask you folks before trying...

I want to use a Topping P50 for it's neat design, compact size and seemingly sufficient current output capability of 2x 1A @5V

My application needs a total of 1.6A on one 5V rail.
The P50 supplies 2x 1A on separate rails
The Regulators used are TPS7A4700 and their App Note states that the chips may be paralleled to get higher output current capability by 0R1 resistors in each output line. I guess I could implement this easily if really needed 😉

But here are my questions:
If I just parallel the P50 outputs with a Y-cable, will it "survive" 1.6A @ 5V?
I plan to place some additional passive cooling on the back side where the regulators sit. Or would this not be needed?
Which other provisions should I take to make paralleling for 1.6A safe?

Suggestions are really welcome!

Thanks and Regards,
Winfried

Hello Everyone.

This may sound like a newbie question, but I don't want to blow-up the P50, so I ask you folks before trying...

I want to use a Topping P50 for it's neat design, compact size and seemingly sufficient current output capability of 2x 1A @5V

My application needs a total of 1.6A on one 5V rail.
The P50 supplies 2x 1A on separate rails
The Regulators used are TPS7A4700 and their App Note states that the chips may be paralleled to get higher output current capability by 0R1 resistors in each output line. I guess I could implement this easily if really needed 😉

But here are my questions:
If I just parallel the P50 outputs with a Y-cable, will it "survive" 1.6A @ 5V?
I plan to place some additional passive cooling on the back side where the regulators sit. Or would this not be needed?
Which other provisions should I take to make paralleling for 1.6A safe?

Suggestions are really welcome!

Thanks and Regards,
Winfried

Hi everyone,

I wanted to start a discussion on the differences between the original Sanyo-manufactured STK ICs and the modern alternatives available in the market today.

I've attached an image showing the internals of three STK412-170 ICs. The first one is produced by Sanyo, the original manufacturer, while the other two are produced by different manufacturers currently available in the market.



Let's delve into:

• The differences in manufacturing technologies.
• The performance of these ICs using objective data and testing results.
• Any personal experiences or insights you might have regarding the reliability and quality of these modern alternatives compared to the originals.

Looking forward to an engaging discussion and learning from your experiences!

I'm repurposing some gear I've acquired over the years to build/rebuild a subwoofer plate amp.
The main power source is approximately ±37v AC from a Toroidal transformer, which should give me around ±50v DC after rectification (I think).
I need to bring this down to a single ± DC output between 9v and 15v for the pre-amp/LPF.
What decent low cost options do I have, other than a secondary power supply or un/rewinding lower voltage taps into the transformer? I can't find a single DC output buck converter that can handle ±50V input, so I'm hoping someone here might be able to point me in the right direction or suggest an alternative..