Hello.

I got my hands on an Mmats D3000.1 with the output shorted.
The reference it uses is IRFB4710, but it is now obsolete.
Does anyone know what replacement would be ideal for this amplifier?

thanks

Hi
this is my first post.
I am looking for solution for my ub9000 . it can not output hdmi signal. other function works

can someone help me which chipset error cause this problem?

Friends, i need suggestions for small bookshelf enclosures for 4fe32 that i found in storage. I am thinking about making small travel system. I got mp3 player, small classD amp, even found tiny sub. Now i need something covering 150Hz up. Something for hotel room instead of headphones. Portable, cute...

Hey there! I know that this is a pretty common discussion topic, but I've looked around and haven't found the exact answers that I'm looking for.

It seems like a lot of people look to tackle the the 300B SET as their first build and are cautioned from doing so. While I'm not super experienced in the world of building from scratch, I've done quite a few restorations of various amps, and I recently built a Darling just to see if building was something I enjoyed. I did, and it just made me want to build more, so here I am. I spent some time reading about sonic qualities of different projects employing the 45, 46, 2a3, 300B, etc. The 300B sounded enticing, but I wasn't sure if it was quite right for me. My speakers are quite efficient (a 3-way JBL system using the 130A, 2410, and 075), so no tube is really off the table, and the power of a 300B isn't fully necessary.

A friend of mine brought over his amp recently, which is a 5U4 rectified, single ended 300B, driven by 2x C3g's per channel. I really loved what I heard–everything just sounded effortless in a way that I haven't heard before. Recordings where I would usually have to dial in tone adjustments just sounded great from the start, and crisp bass was present like I haven't heard from my speakers before. It seemed to suit just about any type of music that we auditioned with, from jazz to stoner metal. So, I'm seriously thinking about going for the 300B. His was done by a Japanese builder using current production ISO transformers and choke (FC-20s for outputs), and I'd like to use the same iron.

I don't know if I want to copy the amp that he has, as the 4x C3g will just add another $400+ to the cost of tubes (I know $400-500 isn't a lot in the grand scheme of building a 300B amp, but I'm also not looking to spend more than I absolutely have to). I also don't want to get into a design that's incredibly different or blows my budget, so I've been looking at the Sun Audio SV-300BE and the Audio Note Quest as other schematics to work from. My question is, would I be disappointed by the sound produced by an amp driven with the 6SN7 after liking what I heard from my friend's amp?

Any thoughts are appreciated. Thank you!

Hi, I am currently working on my poor man's 300b amplifier. I am building it in the case of an old 50's UK military power supply using the transformer and choke. It was stabilised design, and I am hoping to use two of the old smoothing capacitors as well. Both are TCC TYPE 92 1M 750v DC WKG at 60oC. one is 4 uF and one is 10 uF. I am at the point of testing the PSU and a bit anxious of resurrecting these 70+ year old components. When I first gingerly powered up on the variac monitoring the power consumption, there seemed to be a bit of instability, but it seems ok now. I have run it at reduced voltage for about 5 minutes. Apart from DC leakage, are these know for catastrophic failures. Visions of them exploding and catching fire like lithium ion batteries spewing cancerous PCBs all over the place..... They seem rust free, and don't appear to be leaking.

Opinions and wisdom please.



I know they are not 300bs, I did say poor man's....

Hi,

This is my first post so bear with me please,

I have been collecting parts to build the Tim Mellows OTL for about 3 months now and have now started the build..

This is my second recent valve project , I did build a Mullard 5-10 back in the 70s so I chose the Mullard 3 -3 stereo as my return valve listening (mainly due to having the ef86 /el84 tubes + transformers from an old tape recorder) it sounds fantastic but it is not quite loud enough.
I have spent the year playing with different circuits and Tim,s circuit seems the most sensible OTL yet, so I have decided to go with it... I will post pictures of the progress as I go.

Hi, I have this spectrum analyser Kenwood GE-87 (EQ) and the displays are disturbed by a dirty signal as you see in the attach video...

What could it be? I also attach the diagram wiring

Following my publication of the article "Alternative Configurations of the Simple JFET Source Follower" in 2008 :
http://www.diyaudio.com/forums/pass-labs/128571-some-other-source-follower-configurations.html
and the subsequent publishing of the DAO headphone follower circuit using the Loveltech LU1014 power JFET :
http://www.diyaudio.com/forums/head...follower-headphone-amplifier.html#post1130743
there has been a few private builds, as well as a few evolutions since the first circuit.

In August this year, we promised to publish an updated version with a few added features. This we now called DAO SE :
http://www.diyaudio.com/forums/pass...ce-follower-configurations-9.html#post3126245

More information will follow later in the next weeks, but here is a teaser first from our proto build.
It still needs cleaning and then final assembly.
The front hole will take a 5-pin Mini-XLR socket for our AK701 headphone.

🙂


Patrick

Note that I do not suggest building this due to the fact that it is overly simplistic. Might be good as a mod to a broken existing amp.
This is an untested modification to provide an EF3 output stage for the SWTPC Lil Tiger amp. An emitter follower is also
added in front of the VAS to provide a higher input impedance. Thread on the original design with pictures:

https://www.diyaudio.com/community/threads/swtpc-lil-tiger-amp-18w-spice-simulation.414282/​

The closed loop frequency response showed a large peak around 3 MHz so a Cdom cap was added to eliminate it.
This amp as originally designed failed when driving 4 ohm loads and it is logical to keep the TO-126 transistors as
drivers on board and add much bigger outputs with emitter resistors off board. I'm thinking BD911/912 or TIP35/36
which are all currently available.
Note that this is a single gain stage amp and therefore it should be very stable, but EF3s are known to have local oscillations
so proceed with caution.
Front end transistors are all high voltage to support higher supply voltages.
A goal was to have about 100 mA in the outputs, with enough heat sinking one could go much higher into class A,
also 20 mA in the drivers and 5 mA in the pre-drivers.
Again this is UNTESTED so just a concept.
I found the chassis for my amp but can't find the circuit boards right now, maybe in the future.

The LtSpice file is attached:

Schematic:

Halo, I am Bruno, happy to join this group.

Hello!
Im Chris and I live on the east coast of the Great White North. I'm 52 , and a Crane Op by trade.
This is a hobby.

That said. I just enjoy audio older equipment , post 1965 and Pre2005.
I've collected various pieces Marantz, and yamaha. I have also acquired some early 1980s Realistic receivers.

I've on the manufacturer bench a couple of Chinese kits , just to build and play.

I also enjoy going over schematics ,and hope to build one day a few Bryston or Hafler power amps.

Oh I hate to sell this, but the bills are due and I have to let it go. Famed Barney Oliver Hewlett Packard amplifier. Number 284 out of 400 made. Comes with custom speaker cables. But note, it is missing the top panel. Which is just a flat piece of metal. Never got around to making one.

These typically sell for around $1500-1600. Asking $1250

Hello World from Texas

Anyone know how to create a simulation from this schematic

Hello everybody,

Im intending to build an analog tube stage for an ES9038 dac, inspired by Lukasz Fikus circuits. It seems to be differential output dacs, and the board uses two 9038 chips. I saw that left and right negative outputs come together (paralleled?) before entering the opamps, as well as the positive ones.

Since I want the dac negative outputs to send the signal to the tubes grid, I took the signal right before the first resistor, where the left and right negatives are already together. Did it on both 9038 chips, so I understand that I will have stereo output with separate left and right channels, is that right?

All comments will be really appreciated.

Tks all!!

Hi all.

I have a Banda Viking 15.000 which doesn't power ON at all. If anyone have some idea where the softs start receiving power. Also if the preamplifier board on the left is dependent by amplifier board from right side. In a photo attached is a photo with the joint between the 2 boards.

Looking for a pair of Audax TM025C3 1" titanium tweeters.

I have this Chinese copy of the Brazilian design that is powering up to the point where the Power and Clip LED are on.

When I got it, someone had fitted two IRF640N's in the blown side and made things worse. This uses the outputs marked as H9.

I have read through as many threads as come up in search for IRS20957S. This is very nearly identical to the Sundown SFB-5000.

So far what I have done is.

Replaced the blown side outputs with IRFB4127. The other side still has the original H9 installed.

Replaced two defaced 6 leg drivers with ZXGD3005E6TA on the blown side. The other side are still original pair.

Replaced four 15V Zener Diodes, four 4148 and four 13 Ohm gate resistors on the blown side. The other side is original set.

Replaced both IRS20957S. Replaced two 10 ohm resistors also.

Replaced three TL074's

Replaced LM319

Replaced one LMR62014XMFE/NOPB.

Power supply is operational. I have 15V out of the lower supplies now. I have clean drive to Pin 3 of both IRS20957's but Pin 2 is ~3.8V.

I have watched the you tube video. This amp had more issues likely from previous tech fitting in 640's.

I have at one point removed the 4427 and the two diodes. I saw what looked like starts of drive signals on each IRS20957 output pins. I did have over 5V on Pin 2 this way.

Seeing that, I put it all together to get result of both LEDs lit.

What I am not sure of is the choice of using the IRFB4127 or the choice of using the IRFB4127 only on the one side.

Aside from making both sides match, I have replaced everything I have found defective, what am I missing?

I'm having difficulty adjusting the channel positive and negative output current limiters. It seems the pots R541 and R542 have no effect.

All AC voltages are peak measurements not RMS.

If I follow the service manual (Maximum Power Output) and adjust the test input to get a 25.5V output into a 4R load then the output current should be 25.5 / 4 = 6.375A (actual measured is 6.08A). Probably due to losses in the load test leads.
The 0.1R sense resistors R531 and R532 should drop 0.608V with 6.08A current. But instead they drop 0.317V. Which suggests the resistance is actually 0.055R and not 0.1R.
With the pots (R542 and R541) set to max, the Vbe supplied to the sense transistors is only 0.307V.
I don't have any SPS2325 nor SPS2324 sensing transistors (Q516 and Q517) so I am using KSP42B and KSP92B transistors. The tiny current on Vbe of these transistors is tested at about 0.748V. This means the these transistors are always in cutoff independent of pots R542 and R541 settings. Hence, no current limiting.

Causes might be:

• the sense resistors (coils) are not dropping enough voltage.
• the sense transistors I used for Q516 and Q517 have higher Vbe than the originals
• this circuit has AC reactive behaviors I don't understand.

Has anyone sorted this out, short of bumping up the current sense resistor values? To say 0.15R?

Any and all help is appreciated.

Just for fun, I'll start this thread to go along with the one for electrolytic capacitors. Lets see what others would choose/recommend and that they use/recommend.
So to make it more logical as far as comparisions go, and to focus on the application, I'll narrow it down to a part that I am looking at for options, one that would fit the particular footprint (5,10,15mm lead spacing) on a amplifier pcb design I am evaluating. The part selection will have the same capacity and voltage ranges ( 63VDC to 450VDC) suitable for the function of input coupling into a power amp having an input of 62kohm.
This is a link to a Mouser page that selects the candidates, which are in stock at this time, there is enough of them to choose from.
https://www.mouser.ca/c/passive-components/capacitors/film-capacitors/?capacitance=1 uF&dielectric=Polypropylene (PP)&lead spacing=5 mm~~15 mm&termination style=Radial&voltage rating dc=63 VDC|~100 VDC|~160 VDC~~200 VDC|~250 VDC~~350 VDC|~400 VDC|~420 VDC~~450 VDC&instock=y&sort=pricing&rp=passive-components/capacitors/film-capacitors|~Voltage Rating DC|~Lead Spacing

The cheapest is the Panasonic ECW-FD2W105J ( $0.595CDN) vs the most expensive Vishay BFC241611005 ($8.90)

Hi everyone.

I just joined diyAudio. I wanted to gain a better understanding of the principles of tube amplifier design, construction, and operational theory. There is a wealth of knowledge here and many great examples of DIY builds. I am excited to be a part of this community.

I have been addicted to DIY audio for many many years, but just recently decided to give tubes a try. Based on the minimalist design and great sound, I wanted to start out with a single-ended-triode (300B) kit that could be modded rather than going full-on scratch-built as my first experience. I spent considerable time researching and I found myself torn between Sun Valley, Sun Audio, Elekit, and Audio Note. Not a lot of comparison reviews out there for these contenders. Buying an amp without hearing it or touching it can be stressful. I ruled out the ones based on circuit boards and eventually decided on the Sun Valley 300B (SV-S1616D) with the Hashimotos. My decision factors were point-to-point construction, price, and footprint (aesthetics), and the great experience I had emailing with Victor at VK Music. I just received the kit and the tubes last week and the quality is exceptional. I went with the V-cap ODAM upgrade, and I have a few other upgrades in mind as I get into the build - upgrade the IEC to 3-terminal to add earth ground, upgrade the volume pot, add audio grade tube sockets, perhaps better quality hookup wire, maybe upgrade a few resistors, and even considering the idea of a hardwood front panel. I bought the GZ34 rectifier tube so I can experiment with the sound difference between tube vs SS rectification. I am looking forward to the building and learning experience.

Thanks for reading my intro and happy DIY'ing to you all.

WTB: Wadia Digilink 30 or 40.

hi i own an behringer uca 200 but due to crappy op amps and old electrolytics it haves issues with noise and a few other things and my idea is to desolderbit and move it onto a new board. lare there any pcbs that are well made and just have the dac section build out on them or do i have to make one from scratch? im intrested in a new pcb mostly so it could be integrated into other projects or have better quality components and shieldieng.


this is the jrc2740 if im not mistakenand here is the noise floor measured with an osciloscope

WTB: Genesis Digital Lens

WTB: Audio Alchemy TDI PRO-32.

Hello,
I am working with qcc3008 adk and I cannot make it doing what I want.
It's about Bluetooth connection.
No problem for pairing on power on, it find the last connection and connect to it automatically.
But when I go with my phone a little far, the links break, no problem for that of course, but when I go back after somme times, it doesnt automatically reconnect, I have to go in my bluetooth preference and tip on the name of the bluetooth link. Is it a way to automatically remake the connection without having to go in the phone menu?
You can find attached my Config Set Dumb File (in zip because xml seems to don't be allowed here)
Thanks a lot
Hugues

Long story short: I screwed up the length of this port royally

It utilizes a Tang Band W5 for the low end

Anyways....take a look at the screenshots of the model. The one that looks like a proper rectangular 3 way cabinet is how it looks now. Yes, I already built this.

What I want to do is modify it by cutting out a portion of the port.
My questions is whether this crazy outlet shape will still function as port even with the one face still remaining in place. Thoughts?

Hi everyone .
I'm writing to you from France ; i hope you'll forgive my poor english .
I registered on this forum to thank Jim Griffin . Some pictures will help understand why .




It's a modified CBT24 ; the voltage divider diagram is different :


Speakers are bolted on a metal front plate



The whole system is EQed via a miniDSP SHD studio now coupled to a brand new DSP NUOXUN LM848rts . I did'nt have time until now to play with this dsp but soon ...
I have some measurements too .
Thanks , Claude

Hi,

When I started Wild Burro 15 years ago, my dream was to find something pre-existing that could be easily turned into OB speakers with hand tools. I spent hours looking at Ikea, on Amazon, and at stores that sold cheap kit furniture for some nearly complete OB option, but never found what I was looking for. I hadn't thought about it for years, but as I was sitting not-so-far from the factory on a quick work trip to Minneapolis, I suddenly realized that the fodder for my original vision has been common for a few years now: cornhole boards.

For example: https://www.amazon.com/Triumph-Woodie-Tournament-Cornhole-All-Wood/dp/B01K27PX0C/ (I have no experience with any particular model.) So many choices for graphics! And I bet free used cornhole boards are not difficult to find in most locales.

The standard 6" cornhole hole isn't big enough, but a few minutes with any number of cutting tool variations should do the job. I bet the persistent could accomplish the task with a $10 jab or compass saw. The world is awash in jig saws, 1/8" rotary saws (Rotozips), and small sawzall options, many under $50. If you don't mind destroying the front bushing, the $17 Harbor Freight corded drill with a 1/8" rotozip bit might last long enough to cut two holes and then drill the screw holes (go easy with the lateral force).

24" is not wide enough to get as much bass as you can get out of a Betsy but it is wider than some commercial OBs that gained popularity in the meantime. You could extend them any number of super easy and affordable ways, maybe with options based on stiff insulation foam cut with whatever you used to make the hole, pre-cut panels from Home Depot, or whatever else. You could probably play around with the box the cornhole boards likely come in to figure out how big you want the wing(s) to be.

When Wildburro started, many of us were goofing with DIY low power tube amps that were possible to build with less space and tools than it takes to assemble a speaker. My hope was to give us a way to listen to those amps. Now, though, many are playing with super cheap imported tube amps, meaning there might be even more folks looking for simple, affordable speaker options. Even though there are so many pre-built options for speakers, you can't have efficiency without size and for speaker cabinets, size means cost. So, at least from what I've seen, our speaker options remain excessively limited.

If you try it, let us know how it goes!

Paul

My father asked me to help him with fixing his citation 12 and he asked me if I could convert it to MOSFET using Nelson’s design. I said sure. I cleared the board and this is how far I have gotten on the main board.



Both channels have been done this far. I’ve then realized that the bottom of Nelson’s page had an option for a complementary output, which he said is the better design. So from what you see above, I have to remove the diodes as Nelson removed them. The schematics between the two pretty close, but there were a few changes. After investigating, I found that there was a board that was put out by member TAZZZ. This member made more changes to the schematic, but it is very close. I’m wondering if these changes were due to using different outputs and transistors since the originals are no longer available. Regardless, if I use TAZZZ’s design or use Nelson’s from his DIY page I do intend on using IRFP240 and IRFP9240. For the transistors, I am still trying to figure that out. Either MPSA42/92, 2N5551/2N5401, or since TAZZZ’s boards used 2SA970 and 2SC2240 I may go a different direction. Possibly KSA992/KSC1845 for their low noise if the current is low enough, or possibly BC550c/BC560c is voltage is low enough, or maybe ZTX694b/ZTX795a if people consider these low noise. I know Echowars is a fan of them.

Anyways, my question is, is there a design that is preferred? If I go with Nelson‘s original plans, it would be less expensive as I can use the original board. His board layout on the page is very hard to read, does anyone happen to have a cleaner image of it? There is a member here who has TAZZZ’s boards available, his second version of the design, but with the cost of the boards and shipping from Germany, it could add up. I do understand that if I go with Nelson’s design, and I make the changes to the outputs and to the transistors that I may need to make changes to the schematic, so that might be inevitable.

Just curious if there was a preferred design between the two. If shipping from Germany and cost of boards ends up being too much were there any Gerber files made available to have your own printed? I really want to get this amp going for my father. I just really don’t know what is the right way to go.

Thank you,
Dan

Hi everyone,

I've salvaged a few parts from a Sony HCD-XB5, with a working STK4231II.

The parts I have are:
- Power Transformer
- Main Board
- Power Amp Board
- Heatsink

For now I pretend to keep the Power Amp Board and the transformer.

My objective is to make a preamp, output and protection board to use with the STK.

The features I want are:
- Relay driver circuit
- Speaker protection with power-up delay and instant relay opening at turn off
- S/C protection based on the overload detection circuit
- Speaker fuses (I know it's not a great idea but it might protect the OPS, if loads are shorted and the protection does not engage)
- Headphones output based on resistive voltage divider
- Audio preamplifier with equalizer, tone control, balance and volume control
- Microphone and line level inputs

My biggest problem now is the protection circuit, I have the protection IC, but I suspect it might be faulty. There are no replacements for this ICs that I am aware about. Any suggestions of circuits that perform similar to the uPC1237? I have looked at a few, but I need help to understand how the overload detection works.

I also don't know if the voltage divider is adequate or if it should be higher or lower.

I've attached schematic of the output circuit I've made in LTSPice.

The Sony HCD-XB5 manual is a very large file, it is available here, the main board circuit schematic is in page 54 of the PDF, and the power amp board circuit schematic is in page 58 of the PDF. The boards are interconnected via connector G.

Regards
Danny

Hello,

I plan to develop my own board to convert a USB flow to a SPDIF flow, because the "ready to use" boards cannot be easily integrated in my other designs. The highest possible quality is the goal of course.

I have read this old post, but it is 15 years old (!) and it is closed.

I only need to generate a SPDIF output for the classic 16bits/44.1kHz CD format, because I only lesson to this format, and I will convert this SPDIF flow to a ST optical output to feed my Wadia 9 DAC. (if higher rates are possible, why not, but it is not mandatory).

So it seems to me that the PCM2906 is an option (the CM6631A looks complex and requires a firmware configuration tool), but maybe you have newer recommendation ??


Question 1: According the PCM2906 datasheet available here., the attached Figure 36 shows that a Power Supply at 3.85V, whereas I would expect 3.3V: what is the explanation ?

Question 2: As I plan to only use the SPDIF output, I can probably ignore the pins 15 and 16, and consequently C11 and C12 can also be ignored. The pins 12 & 13, respectively VinLeft and VinRight can probably also be ignored.

I will appreciate your replies,
Thank you very much,

Selling the following:

-1 Pair of Seas CA26RFX 10" Woofers. These units are new -- $200
-1 Celestion CN0617M 6.5" Neodymium Midrange -- $40

$20 flat domestic shipping for each or $30 for both lots.

A very interesting article has appeared in EDN, about an ultra-low distortion oscillator:
https://www.edn.com/ultra-low-distortion-oscillator-part-2-the-real-deal/
Very nice and well researched (member @SandyTodorov1 proposed an oscillator using some of the principles described in the article), but one point caught my attention: the use of a LDR optoisolator for the amplitude control.
Quoting the author:

The LDR or photo-resistor part of it is of course linear, but the LED...

Click to expand...

Of course?
That was certainly not my experience. When used sparingly, in oscillators and THD meters, they work well enough, but their value needs to be diluted with parallel and series resistors, and they can easily degrade over time, ruining the performance of the instrument.
To be sure, I made a quick and dirty experiment:

I used a bridge configuration, because I thought it was required to reach a sufficient resolution. All the resistors are high-quality MF made by Ohmic, and U1 is the differential input of my ST1700 distortionmeter.
The voltage across the LDR is 1.4Vrms and I adjusted the current through the LED to be close to the equilibrium, leaving a small residue to allow the THD-meter to synchronise.
I tested various couplers, one from Clairex and another one bought from internet. I also brewed my own version, based on a professional metal/glass LDR mounted in front of a green LED.
The THD at the junction of R1 and R4 (suitably corrected) was comprised between 0.008% for my version to 0.1~0.15% for the others. Not exactly brilliant, and in fact I could have dispensed with the bridge and measured the THD directly

Hi Everyone!

It's been a while since I seriously engaged this forum, so hope you'll be kind. I wanted to let the DIY community know I successfully completed a 3-way center channel using ScanSpeak drivers and a Hypex plate amplifier along with some lessons learned. I have a modest 5.1 home theater. Because of the room dimensions I sit about 10' away from the stereo but often at an angle. I wanted something relatively small to fit on top of an entertainment center with excellent off-axis response and excessive dynamic range. What I did not need was deep bass. This was always going to be a satellite center.



Let me start with the measurements. These are taken with the speaker in place. The red line is on-axis, green is 45 degrees horizontally, and black is 45 degrees above axis.



The curve matches my side speakers, but the 80 Hz high pass function is half in the processor, half in the Hypex DSP.

The components:

• Hypex FA123 3-way plate amp
• Tweeter: SS Illuminator D3004-662000
• Midrange: SS Illuminator 12MU-8731T00
• Woofers: Revelator 18W-8531G00
• Cabinet: Solen custom 24" x 10" x 12" (really excellent work BTW)

Crossovers are LR4 with digital delay on the mid and tweeter. Minimal EQ was needed on the woofer and tweeter while the midrange was left untouched. Some of the woofer EQ probably has to do with surface resonances being placed on the entertainment center. Crossover points are:

• 350 Hz
• 3000 kHz

The Hypex filter designer is not very friendly compared to the miniDSP apps I've used in the past. Especially when iterating settings, but at the end of the day it gets the job done. This project was roughly inspired by the projects of Troels Gravesen, but also, kind of out of frustration with his and several commercial designs trying to eek out every last Hz of bass for a center channel. IMHO, for my needs, they were all too big without much value. That is, I'd need 2-3x more cabinet volume for an ideal ported cabinet to lower the f3 point. I don't mean to denegrate other designs, just want to explain why for my aplication I really didn't follow their path.

This was my first active design and I think what I liked most about it was being able to make a crossover without compromise. That is, it was straightforward to implement LR4 and the matching delays needed. I honestly don't have the chops to have done all of this with a passive crossover. The other thing I really like is optimal power balancing. The woofers get as much power as they are rated for and so does the midrange without wasting anything in resistors or using an excessively large linear amplifier.

Please let me know what you think and if you have any questions.

Hi, all. I'm Mark and I live in Maryland, USA. I've been interested in audio since I was a kid and I'm particularly interested in digital audio both for improving audio playback equipment performance and for measuring audio equipment.

.................................................................................

Hello gentlemen,

I have the following filter on my CD:


This filter flattens the response which would otherwise tilt down towards high frequency. Currently the response is this:



The response is a little ragged 1 kHZ and I wish to tweak the filter to attenuate more on the low end - do you guys have any suggestions (no DSP please) .

The 2-3 kHz hump will be taken care of with a notch filter.

Cheers,
Kris

Hi guys

I am new to DIY. I am German and live currently in Portugal . That’s why the bad English.

In the last couple of weeks I was just reading and surfing in the DIY forum

Why I am here? I would like to get some knowledge about DIY speakers. Maybe I will try my own DIY if I think it is feasible for me and not to complex

Cheers
Christian

Hello, I have made same thread in "Loudspeakers" section, but I think this one is more apropriate. I have Paradigm Studio SUB 15 and it started to shut off on higher volume, after some time it turns back on. I have removed 2 "D class" amps from it and in one I found a failed capacitor it is marked 225K and 250V, no other markings on it. Maybe You could tell me what kind of capacitor it is and with what brand and model I should change it? Thanks

I want to share my projects, learn from audio masters 🙂

I'm afraid I don't really know anything useful about electronics and not very much about audio equipment. However, I do love music and I am fairly miserly . If a piece of equipment is needed I'll try to make it, regardless of incompetence; if a piece of equipment develops a problem I'll try to mend it, ignoring my abysmal track record.

I have more DDDAC stuff for sale:

1. Several assembled V4 main boards - £95 each SOLD
2. Quite a few assembled V4.4 (Tent) DAC boards with Nichicon Muse caps- £95 each SOLD
3. Power Supply - separate listing to follow
Prices exclude shipping.

I’ve been reading Linkwitz’s site and got confused about the shape of open baffle loudspeaker. His LX521 has a keystone, or keyhole, shaped baffle which makes sense if you read his page. However, most other open baffle loudspeakers have very simple sheets of rectangular plywood which are relatively huge. Some builders attempt to round off the corners or have sweeping curves resembling Samurai Jacks kimono. My question is, does it matter? I imagine a smaller baffle will allow for more cancellation of the lower frequencies requiring a larger speaker for lower midrange, or you can use a smaller speaker with a bigger baffle for the same effect. I get that. Also, as the frequency goes up the panel should narrow. -?

Does room size matter? If the baffle is too big it would be the same as installing speakers in the wall. I guess there is a baffle to room size relationship?

I also don’t understand how an open baffle woofer makes any sound whatsoever. I’ve played woofers, not in a box, and there is no bass. So what magic is going on if there is a minimal box with no front or back?

After all that, please post some links or references where I can study this.

You could do this just by feeding the output of the DAC into an ADC, then putting in error correction code that uses that ADC data. Wouldn't that fix the overshoot problem as well as other non-linearity problems?

Hi, I have own this amp since early 00s. Really like it but it has sound problems. When I press Source Direct, the sound works.
When I use the tone controls, the sound is weaker on the left channel and on the right channel the level of sound (amplitude) varies
And sometimes the sound crackles.

Any idea what could be causing this issue?

Br CD

My apology if this has been discussed and I shall be grateful if someone can point me to the right place for the answer, for I searched and did not find the answer that I am looking for.

For a +-35Vdc PSU:

• 2500VA transformer with 25Vac (50A) x 2 output
• total 100mF electrolytic capacitors

What inductor value should I use? I know there is probably different preference but is there a general rule of thumb where I can start and do the tweaking from there.

Thank you.

I can across an original Lafayette KT-550 that need some attention and repair, I have the schematic but no voltage on it in particular I need bias procedure, if somebody have those info please help, thank you so much in advance

Hi guys,
after reading about MyRef and MiniRef I stumbled upon this project, which should be similar to MiniRef I guess, but with bridged LM3886 and a remote feedback that is connected to the speaker terminals, thus taking cable impedance and inductance into consideration.

The guy that came up with this (Dragoljub Aleksijevic) wrote about all the advantages of a bridged approach as well as remote fb, but I presume that's all well known stuff, so no need to go into it.

My question is - is this similar to MiniRef design appart from the bridge and fb (I think so, but with different op-amps, chips and values I can't tell)? Also, do you think this approach could be an improvement?

scheme:


and the pcb:

Hi All,


In the attached schematic, should the input grounds be connected together? Should the same be done with the output grounds?
Is there risk of noise?

Will this circuit work with power supplies from 20v and 22v?

Thanks,

Vince

I’ve had a Sony CDP-790 since the 90s and it’s been working fine. I’ve recently taken it to the heat and dirt of the Italian countryside and it has started to show its age a little. It recently wouldn’t read any cds so I cleaned the laser and the microswitches and reassembled. Now it reads and plays fine but I seem to have introduced another problem – it will not eject cds. My current getaround is to operate the cd drive on a board on top of the machine, so that when I want to change cds it’s a relatively easy (but hugely irritating) dismantling to remove one and replace with another.

• The tray will insert smoothly when it is open. It does not eject.​
• Both the microswitches appear to be working. I can nudge the ‘closed microswitch’ to stop the tray insertion process. I can ‘nudge’ the ‘fully open microswitch’ to stop the TOC reading.​
• When I press eject (or use the remote) the tray motor does not turn (under any circumstance, even if I’ve removed the belt to lessen its load. Instead the machine reads the toc, displays the results (number of tracks and total time) and then (after a couple of seconds) displays ‘track 0’​
• Similarly, after playing a cd the machine will display ‘track 0’. As far as I recall, this is not what it used to do: after playing a cd it would display the number of tracks and total time until the cd was removed.​
• I have tried disconnecting electricity for a few hours to give the machine time to compose itself but to no effect.​

Any thoughts on what the problem is? There were occasional intermittent problems with tray loading/ejecting before and no doubt a new belt would be an improvement but since the tray motor does not turn when I press eject the belt doesn’t (yet) come into it.

https://sound-au.com/index.html

Scroll to project 48
I bought the board a while ago and during several house moves I lost the circuit board and all the bits I had purchased to solder it up.
I have four [4] cheap "subwoofer" drivers from HTiaB bass boxes the amps of which died and not worth repairing.
They have massive roll surrounds and very high Fs ( 47Hz) and a Vas of 25 litres.
I was thinking I should try and use these in as small a box as possible and use the ELF controller.
So the question is this.
Is it a worthwhile project and does the controller work, and is it a beginners thing? My soldering is OK but I'm really a fumble fingers and my eyesight ain't the best these days
I did try selling the drivers here a couple of years back and I got no inquiries at $40- each even after dropping to $30- each

After reviewing several designs in this forum I've come up with the following:

I've seen bleed down after the CRC as seen below.
I've seen the bleed down replaced with a LED.
And I've seen a bleed down with the LED post regulator.
For the sake of simplicity I'm thinking that the LED in place of the bleed down is
the 'best' solution because it serves two purposes. It serves as a bleed down and
a power indicator?

Regards,
Dan

I'm calibrating a Revox B77 and these are the frequency curves. First one, slow speed, second one fast speed.
Slow speed response is pretty good.
I changed C1 on the left channel from 2.7nF to 4.7nF and the curve is now flat.
The right channel has a bump from 1 to 12k and I can't seem to flatten it out. I changed C3 to 1.5nF but that only affects the range above 10k-12k. I tried several other values (2.2nF, 3.3nF, 4.7nF) but that doesn't do the trick. The sound is not bad at all, but still one can hear the difference L/R in this sensitive area. I'm looking for ideas to improve the right channel.

Slow speed 3 3/4


Fast speed 7 1/2

Here's a short video with all content including woodwork created by John Lapaire of what the mic hears going from on to off horizontal axis on an Eminence Alpha 8 for:bare speaker; scaled EON style lens and truncated Karlson lens.

I hope it plays as John's choice of music brought up copyright issues.

With some cases, EQ could be helpful as coud be rising on-axis response.


Login to view embedded media

I hinted at this build previously in another thread, and it seemed to entice some builders as to what I might be doing. The premise of the theme this year was to attempt a multichamber woofer alignment. I had some drivers, and an initial idea started that snowballed into this exercise.

I started with a 3 ltr cherry veneered cabinet that I picked up last summer at one of Meniscus' last sale days. Rear is 3/4", the rest is 1/2" material. I also procured a pair of Kartesian SUB120-8 woofers that same outing for these boxes. The idea was to use a pair of DSA135 PRs to either side, and a yet unnamed tweeter as their companions. I'm pretty sure I hinted at this build in the Wavecor new Cone tweeter (TW045WA01) thread, as that is what I chose to be of equal driver quality. I just could not find another treble driver I wanted to use here.

Then the theme came to be, and I used a bunch of 2x2 poplar from Home Depot and the miter saw to extrapolate the exterior secondary chamber. The further goal to have the DSA215 PR on the rear of the cabinet to tune the rear chamber. Yes, I am using a Double-Bass-Reflex with PRs as I've not seen it done anywhere else. The rear chamber was about 2.8 ltrs all done. Being the 2x2 poplar braces the exterior of the inner box volume, there is no internal bracing. This is something else I have wanted to do for a while. To top it off, the sides and rear would be clad in 3/8" Lexan panels to finish the enclosure and show off the internal construction. The staggered tunings of a DCR, or as in this case DBR (like Fostex), are meant to spread out the tunings in the bass and keep the active driver happier and reduce its xmax load. I feel this application was successful.

Using; almost an entire roll of 1/8" Neoprene adhesive sealing tape, a bunch of poured epoxy to fill in the gaps between the inner and outer cabinets and the mitered poplar joints, a bunch of flush-head 1/4-20 stainless steel bolts and trim-screws, double-thick poplar for the front baffles, and some magic eraser melamine foam and wool/denim fill materials ensued to come to project fruition.
The Lexan sides were flexing with internal pressures, so I had to add some cross-members to mount their centers and keep them taut and stiff. The rear PR had the mounting holes in the Lexan drilled and tapped, and the Lexan panels were drilled and tapped to accept machine bolts to adjoin the rear vertical edges.

Due to the construction and the Wavecor/Kartesian drivers, the name Anomalies stuck.

Then I took to Jurgen Micka's on-line multichamber bass response modeler: https://www.micka.de/en/advanced.php

This allowed to find the proper tunings to make this perform as required without boomy or one-noted bass response. It takes a bit of learning to use it, but things have to be entered 'just so', or it will show skewed results. It showed tunings of the relative chambers to be 55Hz for the inner, and 70hz for the outer. Mind you, the series tunings will show as different when measured, and came to be 84 and 38Hz respectively.

Additional notes here- the DSA135 PRs have consistently measured heavier than spec and tune lower than intended. I ended up adding 10grams to each DSA135 and 74grams to the DSA215. The model in Micka in combination with the PR section of Unibox to help find the masses required came out to 35grams and 70grams. I used the half constructed cabs without the rear chamber walls to measure the tuning to 53Hz for the 10gram masses on the DSA135, which is very close to the targeted 55Hz.

Then problems arose when I started trying to utilize the Kartesian SUB120-8 woofers. I feel the manufacturer could improve these, but did not reply to my query. I feel for $100 each that these should be more error free than I experienced herein.

Problem #1; Another poster pointed me to another user who had had issues with them being noisy. There is no air-pressure reduction path for the woofer when in rearward travel. There is no pole-vent, no vent in the bass-cone, and no core periphery or phase plug to allow this. The other user showed me how he used an exacto knife to cut 2 holes in the cone behind the dustcap to relieve the pressure issues, of which I also obliged. I cut one set of holes, and the noise was improved but still present. I then removed more material, and I ended up with 2x holes, one to either side of the voice coil, of about the diameter of a US dime. I was satisfied with the outcome, and placed them back in their boxes while I worked on the cabinets.

Problem #2; I had the cabinets done enough to try and measure and target the tunings, so I pulled them out of their boxes to attempt the process. I ran them free air with some test tones to confirm reliable operation. The first one was fine, but the second one created an awful racket!! It literally sounded like aluminum oil-canning, but I could not find anything wrong with the cones or the excursion itself. While moving the cones by hand, I rotated the driver to look at all of the operation from all angles for forward and rearward motion. The rearward motion had one spot of the spider popping rearward once past a certain xmax, and would return to flat upon position zero. I got out the Aleene's Tacky Glue and a cotton swab. Then I added the glue to the spider around the area of protest on both surfaces of the spider and let it dry. It did not reoccur upon testing after the repair.

I also had to apply E6000 to the terminals on the Kartesian and Wavecor drivers because I can't stand loose terminals.

FR/HD measurements of the Kartesian were decent, albeit lower sensitivity than I was hoping for. Since I targeted these for the theme, I ran with them, but I also purchased a set of SB Acoustics SB12CACS25-04 as a backup plan if not totally satisfied or if the Kartesians decided to just up and die for another unforeseen reason. At this point I was pretty disappointed and almost washed my hands of them for this project. The xover utilized here was of a series topology, as the name Anomalies pretty much required I do something out of the normal. I also recut the extra 1.5mm radius earlier on the baffles while in the last construction stages so I could just drop the SB12 in after the event was over. At the event and at home, I felt the sensitivity was just too low for my typical use being at ~75dB net for the Kartesian SUB120-8 (Version 1). The FR/HD for the SB12 were also decent, and better than that of the previous woofer by way of more reduced distortion. The swap post-event yielded a much improved sensitivity of about 80dB for the SB12CACS25-04 (Version 2). The bass also sounded more palpable and it blended well with the TW045 much better in both looks and sound. I only had to remove 2 resistors to make the SB12CAC happy and sound right with the proper bass weight.

Edit: xover point is about 1.8kHz, apparently I forgot that bit of info.

Being the volume of this box was so packed full of the intended items, I had to get clever for the xover placement. The tweeter highpass capacitor and a few resistors are placed with strong plastic velcro directly behind the tweeter on the inside top panel, and the rest was placed underneath the cabinet between the feet rails that also supported the input terminals out back. I had just enough thickness and real estate area to make it all fit. I even potted the coils for the tweeter that I personally wound by hand. It was the first time I'd done this, but it was just something that made them easier to mount. I used stainless screws for the coil center mountings, as it did not affect the inductance values.

Conclusion? I like the way these sound, quite a bit in fact. The tweeter has an open and clean quality, and the midbass is really tuneful and sounds great.
Was it worth the effort? For the looks, absolutely! The cherry inside the poplar for the contrast, the wrapping of the Poplar around the cabinet under the transparent sides lets you see everything you want to know or experience. For the work required? Man- these took a LOT of work, a LOT of materials, and a LOT of sound optimization; to get them to sound right. Would I do it again? Likely not. To say I've done a DBR with PRs that nobody else has attempted? That is the priceless quality to my efforts.

EDIT: I just could not leave well enough alone apparently. Something didn't sound like I wanted it after the initial excitement subsided. Normally I don't take this long to get it right. All I did was tweak a couple resistor values because they seemed a hair chesty and almost dull. I don't know that many would have noticed the change to be honest, but it makes them seem more sensitive and a bit more open sounding. I have replaced the graphics pertaining to the previous version.

I hope you read through this and found you learned something from it. I know I did. As to below, this post shows from Version 2, the next post will be Version 1, just to keep them separated. Post 3 will have cabinet images...
1- is an inaccurate summation of the rear-PR nearfield and the V2 system gated response. Bass output should be lower than pictured.
2 and 3 are of the nearfield PR response of V2.
4- gatedFR of Version 2
5- HD of V2.
6- relative sensitivity of V2
7- V2 Impedance
8- xover of V2
9-front baffle of V2

I'm just idly wondering if anybody has uses AAC for speaker boxes?
the 600 * 200 * 50 panels are about $9- each locally about the same cost as ply or high density chipboard

I have this portable "hybrid tube" headphone amplifier. The Little Bear B4-X. I adore it, it sounds just to my liking. It runs on battery power, and I generally use it by plugging it into my phone, ipad or laptop. However, it has a flaw. If it is connected to, let's say, my laptop, and then I plug my laptop in to charge, the headphone amplifier produces a fairly loud 60hz hum through the headphones. When I touch the metal chassis of the laptop, or the metal parts of the 3.5mm audio signal cable leading to the amplifier, or the metal body of the magsafe charging cable, the hum immediately vanishes. Therefore, it is only possible to use the amplifier with a source that is ALSO running on battery power.

I'm not knowledgeable enough to know why this might be, or how I could attempt to fix it. Perhaps there is some modification I can make to the device which will solve this problem?

I have tried reinforcing the chassis ground on the amplifier itself, even adding a second lead from the negative leg of the battery straight to the grounding hole on the PCB. Nothing seems to make any difference. I have some experience building audio electronics from kits. I know my way around a soldering iron. So if I knew WHAT to do, I could certainly do it. I found this sub after a search, and thought maybe someone here could help me.

I welcome any input or suggestions. I've attached a picture of the PCB here, in case it helps. Thanks in advance.

I'm looking at this Pioner SX-737 which has distortion on one channel, the distortion starts after 20 minutes of playing.

The only other thing to mention is that this sandcast resistor becomes incredibly hot after only 2 to 3 minutes, so hot that I can't hold my finger on it.

Any ideas guys? Thank you!

Hi,

Short version: this WOT preamp had 220r resistors on the secondaries even though every schematic I've seen shows 5k-10k. I swapped for 3.3k when putting in an L pad and I'm wanting to make sure this isn't a problem for some reason I'm not appreciating.

I've got a relatively new to me Welborne Labs Ultrapath preamp. You can see a schematic and assembly manual here: chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/http://4tubes.com/2-SCHEMATICS/BY-BRAND/Welborne-Labs/ultrapath_1.pdf

Mine is one of the later, fancier versions in a nice wood box that uses Welborne's proprietary remote stepped attenuator and switching. (as shown here: https://hometheaterhifi.com/volume_12_4/show-report-rocky-mountain-audio-fest-10-2005-page-29.html) It was a pretty neat idea before the MUSES chip (and others) came along. Mine also appears to have been factory assembled.

The attenuator doesn't have a huge range and I was getting too much gain. There was supposedly a gain setting option, but I don't think this one was equipped with that. When I flip the only DIP switches that I think would do that, I get no output. I can't find a good schematic or manual for the attenuator nor are the individual boards or front accessible because it is all glued together (a good reason for not installing those parts).

To deal with the excess gain, I'm trying an L pad on the output (partially because the output transformers, like other WOT preamps I've had, can pick up some hum if this is close to an amp). 6.8k/3.3k works well. But in installing them and replacing the factory R8 (resistor across the secondary of the OPT), I noticed that the resistors were 220r. The only schematics I've found show 5.11k or 10k, which is more what I'd expect. 220r seems like a pretty big load on the output of a pre.

The rest of the oarts values are consistent with schematics I've seen and the selection is consistent with what Welborne would have done at the factory (Caddock). This isn't using R4 or the LED, but not all ultrapath pre schematics do.

Is there some reason it needed more of a load? I can't think of any, but the 200k input impedance it is driving now isn't adding much to those output resistors. I could always source lower value resistors for the L pad if needed. For all I know, there were different transformer versions used and different parts values and I don't want to put these big Electraprints in harms way.

And finally, if you've got a schematic or information on the Welborne remote attenuator/selector set up, I'd love to see it.

Paul

Plug and play. No drivers required. Nice sounding DAC, made with quality components. Nice acrylic top plate so you can see inside. Very cool look.

$125 plus shipping OBO

Thanks!

I remember himself best as the sleezy prof in "Animal House" but his signature performance was as a surgeon in Korea.

https://www.wsj.com/arts-culture/fi...-88-88866396?mod=hp_trending_now_article_pos2

Hi I used to make the superb Faradaysound low density concrete cabinet loudspeakers. Someone from this platform enquired about them, as I still provide a diy construction booklet. Anyone else interested? Peter

I am interesting for the Mundorf M-Lytic AG (10000uf 63v) for replacement my old Sprague 81D (6800uf 63v) on my PSU.

Would anyone can tell me what is the sonic quality different in between Mundorf M-Lytic AG and Sprague 81D?

Some people said the Mundorf M-Lytic AG sound bright. It is ture?

I like the sound transperant with a good dynamic.

Hope someone here can help me to find out the best caps which may suitable for my need.

Thank you,


Tom

Hello, hope everyone has a great day !

I'm working on this shunt regulator project, a high voltage (250-300V) design for tube amps. The error amplifier is a vanilla LM324 with a separate supply (labelled Vcc below) external to the regulator board. See schematic below.



I have made the error amplifier section as a separate board and it seems to work as expected. However for a build where it would be integrated in the whole regulator I have outstanding questions:

• I placed the final load resistor R_load2 on the separate board so measurements could be made, but is it necessary now that the output drives the mosfet gate?
• In a general sense, are load resistors needed between cascaded op amp stages and if yes what are the requirements for determing an optimal value? Or on the contrary are they detrimental to the performance? For example in my circuit is the first gain stage load resistor R_load1 necessary? I have put large-ish values for R_load1 ansd R_load12 so as to not load the stages too much.
• Should I put a series resistor on the non-inverting input of the first gain stage for protection? The error voltage potential divider's top resistor will limit current for positive swings but what about the current from the speed-up capacitor C1 or in the case of reverse ground voltage when schottky resistor D9 starts to conduct? If a series resistor is needed I think it should to be equal to the inverting input resistor Rg1 (10K) yes?
• The LM324 is a bipolar input opamp, so it needs some input current. Given the high impedance of the error voltage potential divider, should a FET-input opamp be used instead? I have read somewhere that FET inputs are sensitive to noise voltage, not sure if it would be better suited for this task. My understanding is that the current draw of the bipolar LM324 input would just add to the divider chain current and the offset in output voltage can be compensated by adjusting the reference voltage.

Please do not hesitate to signal any errors and aberrations you notice, I'm relatively new to this, especially the opamp part. As always I appreciate any input on optimizing the circuit.

Regards.

I've seen a lot of talk about external heat sinks but not how to actually mount them. Can I mount my amplifier IC's onto my case inside, and heatsink at the same place outside and use the case for heat transfer? Or should I cut out the case so the IC mounts directly to the heat sink (with isolating material + continuity test)? I have heat sinks at home that are flat on one side and have fins on the other.

I have 2x ceiling speaker boxes made of MDF and plasterboard for my KEF Ci160QR speakers.

I read it's a good idea to stuff the boxes but I'm not sure if I should be 'loosely' filling it with polyfill or lining the cabinet with polyester wadding?

I don't wish to use anything like rockwool or fibreglass which would pose a respiratory risk.

What is ideal here?

Thanks.

I am a new member to diyaudio, recently got into electronics and interested in getting better and understanding the principles behind building a good amp, dac, etc. There's a lot of good knowledge and builds on here and would love to be apart of the community.

I'm new to reading schematics (and designing power supplies) and curious to know what is happening in the Baby Ongaku PS. I should note that my ultimate goal is to use a transformer I have on hand that doesn't have a 6.3V CT.

So, from what I can tell, the amp has what is more or less a choke input featuring 22uF and 100uF filter caps followed by a 100k bleeder resistor. Does that sound about right?

When it comes to adapting the schematic to suit my PT, would I just run the 0V and the 6.3V from the PT to the 12AT7 and put the 22uF cap and the 100k bleeder resistor directly to ground?

Many thanks!!

GD Folks,

I’m having a problem with IRS2092/CSC3120 oscillating.

Over the past couple of weeks, I got in a couple of DS18 CandyX5B and a Taramps TS600x4. Each amplifier displays the same failure mode.

The DS18 5CH, employs either IRS2092 or CSC3120 for the sub channel, the Taramps uses IRS2092 for all four channels.

Taramps; shorted outputs in three channels, replaced IRS2092 and output FETs, two of the three channels powered up ok, good R-R oscillation, however the third channel appears like it wants to start R-R oscillation, zooming on the scope it does have sq waves before it flatlines and it repeats this until the unit is turned off.

DS18 X5B; 3 units came in, each with similar reports of sub channel not working. One unit uses CSC3120 and the other 2, IRS2092. Each unit appears like it wants to start R-R oscillation, zooming on the scope it does have sq waves before it flatlines and it repeats this.

Thus far I’ve only messed with the DS18 with the CSC3120, I’ve replaced it with a new IRS2092, and used various values of caps for pin 4 to alter the oscillating freq, I’ve measured the resistors around pins 7 and 8, both are with spec. I’ve compared these values with the other two DS18 amplifiers, measured and all measure around the same resistance.

In the one unit I messed with, I replaced the resistors with new. All to no avail, the unit remains the same and shows as if it is trying to start oscillating. All other components around the FETs/output of the drivers are testing ok.

I’ve attached a couple of scope screen captures to aid with my description of what’s happening. Anyone ever saw something similar and remedied it?

Hi all!

I am a new member. I started getting into audio maybe 5 years ago. I started with mass produced speakers such as KEF and other well known brands but soon got into open baffle builds through Caintuck Audio. I've since built/bought maybe 4 pairs of open baffles, and then built some cabinet speakers using single driver designs, and have not looked back!

In the search for the perfect woofer and talking to people in my state I discovered a man who built speakers for a large theater in my country (teatro de São Paulo), I went to his house and discovered that he built speakers and in my opinion they looked good built and very good.
Any thoughts on handcrafted speakers?
What should I take into consideration?
I didn't ask him but I will ask here, how do I get the tille small parameters for these homemade speakers?
There I saw brands of speakers that for me were examples of speakers such as Bose, Celestion, Selenium, Fosgate, Ophera, Harman Kardon, Focal and the famous Sony.
And all these speakers he was arranging

Hello - my name is Nik. I'm from Denmark - and to be very specific, the small island Funen in the middle of this tiny kingdom (until recent a tiny queendom).

I'm absolutely new to this stuff and hope for some help.
I saw a thread here about a rebuild of a NAD C370 which inspired me to take my NAD apart, to do a rebuild of my own - with some help (I hope 🙂).

Well that must be it for now...
Nik

While checking the output transistors in my 565 (in circuit) I measured 0.018 ohms when checking emitter to base, not .05 .06 volts. All the outputs I checked ,even on the working amp tested this way. Does this mean that they are shorted?. I have not been able to go further until this question is answered. Yes, this is the first transistor amp I've tested. Please help. Thanks, Kevin

Some were upset by my last Repair / Rebuild.
So all I will say is this.
They sounded like rubbish before.
No treble, and one side had almost no mid-range.
I investigated, found many issues, and it was decided to do a full rebuild.
These are factory original. Matching serial numbers. Never touched before now.
Did you notice one side using different parts ? From the factory.
After the rebuild using far superior parts, everything is now working as it should.
Plus some.

To head off all the old worn out arguments.
A lot of the capacitors are in parallel banks. The capacitance of each bank was matched to the original.
The old inductors were measured, and the new inductors were selected for correct inductance AND dcr.

If the owner wishes to comment further (they are a member here) then that is up to them.

Hello,
I'm facing an annoying issue with my DAC. I use the Denafrips Hermes as a DDC, connected to my PC via USB, and outputting AES/EBU to my DAC. The problem arises when playing files above 96 kHz or switching off my PC ; the DAC produces an irritating ticking sound that seems to come from a relay ( RY2 as shown in the attached schematic) .
Are there any modifications that can be implemented to avoid this ticking sound?
or
can i just jumper RY2's Pin 7 to 8 and 4 to 3 and remove the relay from the digital section ?
thanks

Would it be possible to 'erase' a magnetic multi-pole strip / sheet to 'record' a short piece of low fidelity music on it (using an electromagnetic head etc.) ? The resulting 'tape' is then expected to be 'played back' using a hall-effect sensor, much like a music box. Kindly note that this cannot use a standard cassette system for legal reasons.

What would be the feasibility of the above and any issues (magnetic or other) that one might face while doing so ?

Thanks.

I’ve been playing with an equalizer. I discovered that my speaker system sounded better when I boosted 3dB at the woofers’ operating range. Since my speakers have 2 woofers per cabinet, I realize that one way to achieve 3dB gain at woofers’ operating range is to adding the third woofer to each cabinet. However, I also realize that paralleling 2 woofers together will obtain 6dB gain on woofers’ operating range. So what is the benefit of adding the third woofer to the existing two woofers connected in parallel? Should the 3rd woofer be connected in parallel or series, assume all drivers are identical?

Guys,
i know you both have your webpages excel workbook on Brian's , and freecad scripts on Lords
i want to tweak this design for different drivers
is the Staiper mini scooper MS-18 MK2 and MK3
source page here
MS-18 MKIII

Hi ! i have this british amp with output devices mounted of the metal case that works as heathsink ... very british way

in a word it looks quite messy
In a car audio amp i have seen this much more elegant solution with a thermal conductive sheet and a bar to keep the devices attached on the surface


This solution among other things will allow for a easier removal of the entire board
I have spotted some bad solderings but i would like to work out of the case
Any suggestion ? Thanks a lot
gino