I've got an original Elekit TU-8200 that I built back in 2016. It's developed a hum in the left channel, audible in the speaker as well as headphones. I've swapped the pre-amp and power tubes to no effect. Googling led me here (well, the Elekit forum here, but alas I can't post there yet 🙂, and suggests I need to replace my FET(s).

I've measured the voltages at the documented test points, and several on the left channel are out of spec. Anything else I should check, or just order some FETs and swap them out?

And @vkung if you're watching, I suspect you'd be able to nail this one down quickly.

Thanks!

Voltages (12AU7 and 6L6EH):

1 -> 3.8
2 -> 3.5
3 -> 3.6
4 -> 3.6
5 -> 123
6 -> 119
7 -> 127.1
8 -> 116.1
9 -> 220.2
10 -> 208.9
11 -> 1.1
12 -> 0.58
13 -> -20
14 -> -17.3
15 -> 0.03
16 -> 0
17 -> 0.46
18 -> 0.43
19 -> 285.8
20 -> 271.5
21 -> 285.4
22 -> 318.3
23 -> 291.3
24 -> 279.8
25 -> 287.4
26 -> -33.2
27 -> -34.5
28 -> 5.9
29 -> 6.2

Hello

just a quick comparison between a CD (16Bit/44,1KHz-Rip) and a LP (16Bit/48KHz-Rip).
Same song and same audio segment.
First: Audacity > Analyze > Plot Spectrum

CD
LP

Second: spec
CD

LP


I am amazed, i had expected a worse quality of the LP.

Thorens TD126 MK III + Ortofon OM20, Pioneer SX 950, ACER D270 for analog ripping.

Happy holidays to you all

Hello all. I am planning to upgrade my Buffalo IIISE (9018) DAC, which currently uses a Sonore Audiobyte USB to I2S board that can only handle DSD up to DSD128. My source is a Small Green Computer Sonic Transporter i9 and player is a Sonore Signature Rendu Deluxe. Works great upsampling everything via HQPlayer to DSD128, but I'd like to explore the higher rates.

The new setup will feature the BuffaloIIISE Pro (9028) and a JL Sounds USB to I2S board capable of handling DSD512.

In preparation for the build, I was wondering if anyone who has done such a build could recommend the proper DPLL dip switch settings for the BIIIPro 9028 DAC to give a good lock on DSD256 and DSD512 with no extraneous noise while minimizing jitter. Of course I will do my own experimentation, but having a starting point is always helpful!

Thanks in advance for any advice given!!

Hi, I plan to use the following transformer setup:


The diagram bellow shows a 'regular' hum balancer wiring.

In this case there must be galvanic connection between the fillament windings and ground.

R-drop resistors are needed to drop from ~9v AC to ~6.3v
R11-12/ 21-22 are chosen 1k so that it has neglibile effect when it shortens the transformer winding (leftmost), and the R-DROP.
There are seporate R-drop and hum balance wiring for two identical tubes - this is for symetrical load distribution between the two transformers.
The HT transformer is connected that way as well - to share load from both primary transformers.

But would it actually work?
As far as I understood, the hum balancer shifts the fillament AC phase, so it kind of cancels out relative to the tubes power supply.
Here the balancer is connected to ground and the fillament potential 'starts' ~3 volts above the ground.
// R-drop should be ~8.1 ohm, R fillament is supposed to be ~18 ohm
There could be other options for wiring, I allready got confused drawing this one 🙂

Next option is regulated DC power supply, so the rectifier kind of 'isolates' the fillament ground from the common ground.
Least favourable is adding seporate heater transformer.
In general I want to keep it as simple as possible with the layout above.

Regards - Emil

I have a Schiit valhalla 2 preamp. It was working quite well till last month, after which it started giving a problem of losing one channel after about an hour of usage. When I turn on the amp, it plays just fine, then after around an hour or so, the left channel starts to distort/crackle and then mutes itself. It then restores itself after about a minute and sometimes it doesnt. I have tried a few ways to debug the issue from Changing to New tubes as well as changing New tube sockets as well as changing to a New potentiometer. But the problem remains. Tried cleaning the input and output rca Jacks as well but to no improvement. If I use a different preamp, everything plays just fine, so no issues with any connected equipment as well.


I suspected a cold solder joint somewhere, but could not really find one upon inspection (but it may be there)

Can a failing coupling capacitor be a suspect ? Tried using a magnifying glass to inspect a cold solder joint but could not find one. Whatever looked dry, i reflowed New solder on them.

Please advise

For Sale: Emerald Physics CS2 speakers with MINIDSP 2x4

Sold these to a friend years ago and recently traded them back for a Hypex amp.

I have the original CS2 boxes (a bit ratty), but the original Behringer DCX2496 was replaced with a standard MiniDSP 2x4 unit.

The speakers themselves look very clean with zero issues. Pickup in west sub of Chicago only....to big/heavy to ship.

I recently built a "pseudo clone" of these CS2 with the four Eminence 15A Alphas but with Heil AMT tweeters that I am sticking with (builder's bias?).

How's $675 picked up?

I also have a pair of PASCAL stereo amps 500Watt/125Watt (4 channels total that are prefect to biamp these CS2) that can be added to the sale if needed...

Hi, LM1875 circuit:



The 1k/ 330p network is a low pass 482kHz I guess. Is it a good idea to tweak it to around 10kHz?

The datasheet states that the chip is stable at gain >= 10.
Is it ok to lower it to 6 or 4?
The preamp levels are high and I don't need gain of 10.

The circuit is intended to work in the range 2k5 - 10k. A HF driver for a bass guitar cabinet, 2k5 active crossover before the amp.
I want to minimize all hearable HF noise, introducing LPF and reducing the gain.

HI,
I am hunting a single to pair up a single I have had a while. They're from the Eico HF50( and maybe HF52 ). Trade or purchase. I have some UTC LS-series or perhaps some tubes( ask, I just might have what you seek ).

Douglas

I'm looking for either....

A new stylus for my current Ortofon 2M Bronze. (The Black stylus fits),

A new Denon DL 103,

Or I've just see a Denon DL 103R for a similar price.

Turntable is a Project 1 Xpression with carbon arm and my phono stage is a Cambridge Audio Alva Duo so MM/MC.

I know carts have been covered lots but I just want to know if there's anything else I should be looking at for around £450? Or if not, what would be the best of the 3 I've mentioned.

Any advice appreciated.. And Merry Christmas!

Hey Guys
Since it is getting almost impossible to find Elna Silmic anymore,
What caps have you found that are very similar that is a good replacement?
I like that smooth warm sound
Of those silmics .

Scott

Hi Guys, What could be possibly be causing this problem, any advice would be appreciated?

I’ve been attempting to formulate an empirical formula for finding Q-factor of second-order filter by using graphical method. Say we could find Q-value from the frequency response curve. And, finally, I obtained it, that is, Q = 10^(x/20) where x is the -dB at Fb (box resonance). I verified with theory and many examples and it worked.

For example,
if x = -3dB, it yielded Q = 0.707 or Butterworth slope
If x = -4.5dB, it yielded Q = 0.58 or Bessel slope
If x = -6dB, it yielded Q = 0.5 or Linkwitz-Riley slope
Etc.

Nonetheless, that formula can only be used for Q of enclosure. It wouldn’t work for electrical fIlter because I cannot find the corner frequency on the amplitude curve. So anyone advise me how to find corner frequency from the frequency response graph? Don’t suggest me to look at -3dB point because it would be correct only for Butterworth filter.

Hi,

I am from France. I am in my fifties and was really passionate about electronics as a teenager. I missed the opportunity to work in this field for various reasons and did not pursue it even as a hobby. But....

I recently bought a Meridian 557 amplifier and decided to recap it myself. This may be the first of a new long list!

Thierry

Over the weekend i came across an old FET 2 preamp in slight need of attention (blown MC input, malfunctioning muting relay).

This was hardly a statement product in its heyday but the quality of case, pcb and layout really impressed me. The sound also exceeded my expectations.

Fwiw, i think that it would make an excellent simple project for anyone wishing to build a nice sounding discrete preamp. I am fairly certain that its phono section is better than any of the el-cheapo, single opamp designs.

So, this morning i attempted drawing the circuit. Although trying to be careful, i may have made an error or two, so if anyone spots anything funny please let me know.

The preamp has a separate MC gain stage which, being a common gate circuit is rather unusual. It uses a parallel 2N5566 and i found that a 2SK389 works quite well. The trimpot is used to set 0v at the input which seems to be quite reliable and stable.


Predictaby, this is the worst sounding part of the unit. Most probably because of the PS - remember this pre is built for a limited budget. Entire pre is supplied from a nice but tiny 30VA 2x20v toroid followed by a bridge, 2x2000uF Mallories and separate 7824,7924 for each channel. No local regulation, just single caps per rail near the line amp (no markings, must be around 100uF)

IME a MC gain stage requires the absolute best PS with batteries or dedicated Jung type regulator to sound acceptable.
Coupling cap to MM stage is a 1uF polyester-looking Electrocube.

R1 is selectable for 3 values - 50, 100, 200 ohm.

I've been wondering how to calculate crossover frequency of the third-order crossover and its parameters from the schematic.

Let us consider second-order crossover, there are two formulas to calculate the parameters of the crossover which are crossover frequency and quality factor. The crossover frequency of the second-order filter is calculated from resonance formula: f = 1/(2 x pi x sqrt(L x C)) and the quality factor is calculated by Q = sqrt(CR^2/L).

But, how about third-order system? Are there formulas for calculating crossover point and Q-factor as the second-order system?

I know the simulator software can do it very well. But sometimes it should be more handy with hand calculation.

Assume we have a series 6.8uF capacitor and a shunt 0.2mH inductor, we can easily obtain crossover frequency and Q-factor of this second-order filter by using two formulas above. What if we add a second series capacitor of about 18uF to it, now the crossover is converted to be third-order system, can we find crossover frequency and Q-factor (if any) of this third-order filter?

Hello all, long time lurker here.

Hi all 🙂
After successfully completing excellent SA2014 from @astx , I decided to build the SA2015 V-Mosfet (4x SA2015 in one box). I want to build this amplifier for Bi-Amp wiring and compare with single amp wiring (SA2014).

This 4x SA2015 V-Mos will be housed in a single 5U/400mm box from modushop. The feeding of these 4 modules will be handled by 2 massive 500VA toroidal transformers from Toroidy_pl. Each module will have a separate power supply (4x 15.000 uF Nichicon).

Original thread ASTX: https://www.diyaudio.com/community/...ance-class-ab-power-amp-200w8r-400w4r.235194/

SA2015, PSU , transistors --- (all from astx)


Softstart (incl DC protect)


SSR3 speaker protect


If anyone would also like these protections they can join the ongoing GB.

Ground Loop


* All input and output connectors will be of premium quality as well as the internal cabling, ...probably from SUPRA.

Hello.
NAD T748 V1
Works fine, just one problem.
Analog Source one......no sound.
All auther sources works fine but the sound appears only after 10 seconds

That is, if I select an input, it appears on the display but the sound will only appear after 10 seconds. There is never any sound at analog input number 1.

Factory reset doesn't help.
Last firmware is installed.

Thanks


Service manual

https://acrobat.adobe.com/id/urn:aaid:sc:EU:7d422752-fb6b-45b5-aaa3-3ae30999865c

Good evening, everybody! I’m from western Ukraine, city Khmel’nytskyi. It’s my new account, because old one (viking_km) is deactivated since I didn’t used it for a while and it was registered using ruzzian email a long time ago. Now I’m here because my interest to build devices with good sound has been reopened again 🙂. Right now I want to build a tube RIAA phono stage and buy some vinyl turntable

I guess you'd say my hi fi tastes are high-middle-brow: bought my first AR speakers, Marantz amp and Shure V15 in about 1972. I have mostly Yamaha electronics now, though I'm no longer much of a fan of the variable loudness control that led me to Yamaha originally (I think it is really a variable high filter). Still like AR speakers but I've picked up JBL's and Bose and Klipsch over the years. I found this site by looking for a particular topic of how stylus force deforms a vinyl record.

Hello everyone,
a few years ago I bought my Elekit TU-8200 which I built myself.
Now I would like to check all the voltages as suggested in the manual but it seems to be quite difficult as the components are mounted upside down on the board ....
Is there someone on the forum who has already marked all the control points on the welding side who wants to share his experience, in order to help even inexperienced people like me ... ????
Photos would be appreciated
Thank you in advance 🙂

Genuine Sanken SP-40w. This is single channel one no. IC. I purchased this from DiyAudio member who pulled it from his amplifier. US $15 + shipping + paypal fees. I guess Sanken S-40w is same as this IC.


regards

Hi Guys, I recently purchased this sub on the belief it was working. When I switch it on it makes crazy noises. When connected to a source it sounds like it's playing full range but also when those strange sounds. Any suggestions?

This was asked for in another thread, so I thought I'd start it here, though it was not asked of me.

I have only really assembled one pair, which I dubbed the "Foster-Franken-Coax". This used 12" Foster woofers and 1.5" Foster dome tweeters, both from a pair of Sears-branded speakers.



I have no data or measurements, this was before I got more serious into the hobby.

The tweeter was held in place via a short length of ABS pipe, glued with epoxy to both the pole-piece and tweeter back-plate. The tweeter leads were made with solder wick going through the cone, where I made a small slit and sealed it back with glue. I briefly tried these in a Karlson 12" box, where they performed horribly, way to small Vb for the woofers. I then stuck them in a large-ish sealed box and gave them away to a buddy who I haven't heard much from in a long time. That was about 10-12 years ago.

Now, those who have handled these tweeters know they are fairly massive. I can't help but imagine that since then, the glue must have failed or is about to. Whether this happens at the pole-piece or tweeter back plate, it will brutally and irreparably take out either if not both the woofer cone and voice coil. I should check up on said buddy and see if these have met an horrible demise or if I have underestimated the strength of Lepage 20 minute epoxy.

What are your experiences with DIY coaxial drive units?

Hi,

I use a chinese XMOS I2S interface board (Crystal upgrade XMOS XU208 DAC + cpld card USB digital interface I2S DSD output for AK4497 ES9018 ES9028 ES9038 decoder E4 007-in Amplifier from Consumer Electronics on AliExpress) with a chinese ES9038 board (ES9038 Q2M DAC DSD Decoder Support IIS DSD 384KHz Coaxial Fiber DOP | eBay).

Several different drivers were tested, they all produce the same issue: I get periodic audio pops (buffer overflow/underrun? Recording+its spectrum in attachments) every few seconds. This does not happen when I feed S/PDIF directly from the PC to the DAC.

I've done a quick test playing back a 400Hz test signal via foobar (happens everywhere - videos, browser, games) and depending on the sample rate these pops appeared in different intervals:

44100 Hz: every 88s
48000 Hz: every 95s
88200 Hz: every 44s
96000 Hz: every 44s
176400 Hz: every 22s
192000 Hz: every 25s

I've tried the same USB interface / DAC combination on three different Windows-PCs (all Windows 10), they all show the same result. Then I tried installing a fresh version of Ubuntu, didn't change any driver related settings, and there are no pops at all with the standard alsa drivers on any sample rate. Since the DAC itself doesn't "see" the OS, I guess it's not a DAC issue.

Apparently this XMOS device doesn't work properly under Windows 10. Did anyone experience something similar with these devices? Could this be a firmware related issue which can be solved by flashing the firmware?

Are I2SoverUSB, diyinhk and WaveIO still recommended USB/I2S interfaces? In case I find no fix I'd buy a new interface and would much rather have existing customer support this time.

FH3-inspired Foam Core Mini Build HOWTO

I've gotten some requests to provide details of how to build the FH3-inspired mini speaker in foam core and thought that a new thread with the "how to" might be useful.

If you have been following the Foam Core or Cornu Spiral threads (http://www.diyaudio.com/forums/full-range/223313-foam-core-board-speaker-enclosures.html and http://www.diyaudio.com/forums/full-range/225622-ever-think-building-cornu-spiral-horn-now-you-can.html), this will be familiar. I recently built a smaller all foam core speaker inspired by the very elegant FH3 to see what it sounds like without having to cut any wood or having to invest too much time in the shop (if I had one). Being made of foam core boards from the dollar store, the maximum dimension would be 30 inches. I also wanted to use a smaller less expensive driver to match the smaller cabinet and to save money. Having my favorite budget Vifa TC9FD driver (Vifa TC9FD-18-08 3-1/2" Full Range Paper Cone Woofer 264-1062) on hand, I set out to design the new mini FH3-inspired speaker by scaling the cross sectional areas of the speaker's horn as a function of the driver piston area Sd. My calculations showed that the FH3 has nominal cross sections of 2x Sd at the folding point, 4x Sd at the base, and 1.06 x Sd at the terminus choke point. These were calculated from the published dimensions of the FH3 (http://www.google.com/url?sa=t&rct=j&q=frugel%20horn%20mk3%20plans&source=web&cd=9&cad=rja&ved=0CGMQFjAI&url=http%3A%2F%2Fwww.p10hifi.net%2FFH%2Fdownloads%2Ffrugel-hornMk3-1v0-250212.pdf&ei=h8TuUNO5K4W80QGh2YD4AQ&usg=AFQjCNFRzgZK1QjpBt2V3mP5wK3U97zfUw&bvm=bv.1357700187,d.dmg)and one of the recommended drivers - the MA CHR70. Armed with this knowledge and constrained by a maximum height of 30 inches, and knowing that the cabinet needs to be at least 4.5 in wide for the baffle to properly mount the Vifa, it was a simple matter to derive the cross sections at the fold point, the base, and the terminus for the Vifa driver.

The resulting principal dimensions that came out of the scaling were surprisingly even and simple: 2.5 inches x 2.5 inches x 2.5 inches at the fold point for a base depth of 5.0 inches, and a terminus gap height of 1.33 inches. The cabinet is sloped back at an approximate 5 deg angle to form a parallelogram when viewed from the side. Rather than deal with angles, I measured a setback of 2.5 inches from vertical to approximate the angle. Thus will also require the height of cabinet (vertical) to be only 29.9 inches in order to preserve the 30 in length for the baffle. So we now have a very slender looking cabinet that is 4.5 in wide x 5.0 deep x 29.9 in tall. Such a cabinet would not be very stable and tip over easily requiring outrigger feet for stability. Foam core construction permits the neat ability to make compound or complex curved walls at will. Thus I decided to curve the rear horn walls outwards to give the base stability and provide more expansion for the rear facing horn mouth. So I expanded the rear mouth from 4.5 in to 12 inches over a distance of 10 inches.

Before actually putting razor to foam, I simulated the response in HornResp just to make sure the bass output was reasonable and to see where the tuning frequency was. It looked ok, with a main low bass peak at about 70 Hz and a dip around the 125 Hz region which is OK because that is the Fs of the Vifa and there should be enough output from the driver to fill in. diyAudio

The build went very smoothly, one just has to use a good straight edge (I used a masonite panel) and a sharp razor. Make sure you account for the thickness of the board (3/16 in) as the dimensions above are internal dimensions. Draw the plan on one of the sides and begin by hot melt gluing the back panel. Use a square piece of foam core as a gage to ensure 90 deg angle while the glue sets. Then glue on the internal angled divider. Also use the 90 deg gage to ensure squareness. It helps to glue in sections at a time as 30 inches is too long of a stretch to do in a single stroke with hot melt. Then glue the front baffle, which I made wide to cover the front joints. It is trickier than the back or divider to glue as it is not lying directly on top of side. You can make construction easier by gluing it on the side just like the back if you make the sides deeper by 3/16 in to accommodate the thickness. Then bracing needs to be added, I had 3 major brace locations. These are cut to fit and jammed in place with hot melt taking care not to distort the squareness of the cabinet. I also added some front brace strips to serve as ledges for the final side to be glued on. I also added a second 4.5 x 4.5 in piece of foam behind driver for a double layer to give more support for the driver mounting.

Then a curved piece needs to be glued over the terminus to provide a smooth flow at the mouth. Curves are made by scoring lines deep enough just to pierce the paper on the concave side to allow the foam to compress when you bend it.

Next comes mounting the binding posts and adding wire to receive the driver once it is all buttoned up. I hot melted the binding posts onto the back and added crimped wire connectors with wiring for the drivers.

Now comes the dampening plan, I used the suggestions from the FH3 plans and added pillow stuffing into the closed end and used open cell foam to line the walls adjacent to the driver, ideally felt should be used. The top is left off for adjusting stuffing after build is complete. Now the second side panel is glued on with pva glue and a combination of hot melt at stragegic points to act as a tack while pva dries. I used books and dumbbells to clamp the side. Rubber bands can also be used to apply tension to clamp baffle edge to side as side is not on top of baffle.

Once the side gluing is complete, check for any leaks or gaps and fill in with more pva or run hot melt glue over gap to seal. Now the base is glued on with hot melt. Do the straight sections where the main box is first, then glue the curved sections in bits at a time while bending the horn mouth outwards like a wing. Hold in place with your hand while hot melt glue sets. It makes a nice graceful curve which now doubles as support feet.

Finally, cut the hole for the driver - use a template and center it at 2.5 inches down from the top. Glue small strips of wood where the screws go to provide purchase for the wood screw threads. Install the driver and now add stuffing to cavity behind driver and maybe 2 inches below driver but no more as that will kill bass extension. Use a temporary means to fasten top on and listen to speaker, and adjust stuffing as needed to taste. I used quite a dense pack behind driver to absorb reflections that could go back out the cone. Once you are satisfied with sound, hot melt glue the top on and you are done.

How does it sound? Fantastic! There is plenty of warm deep punchy bass emanating from the terminus. The Vifa does a great job with the mids and highs. The sound stage and imaging are superb. The sound stage does not feel as wide as the Cornu but that is to be expected as it is not 24 or 28 inches wide. I like how the bass and mid bass sound more balanced than Cornu, but overall, the Cornu's wide sound stage and impressive mid bass still manages to knock my socks off. The foam core FH3-inspired speaker definitely is one of my favorites and I understand its popularity: not only does it sound great, it looks really nice. I like how it sounds so much that I started on the build of the second channel and promptly ordered more Vifa drivers as I am borrowing the ones from the Cornu spiral.

Each speaker uses about 3.5 sheets of foam core board. The total cost of each speaker is under $20 including driver, binding posts, foam core, and glue. The build time (not including glue drying time) is about 3 hours per speaker. The second one goes faster due to the learning curve.

Give it a try, it is a lot of fun, they sound great, and look even better. 😀

these designs are NOT in any way approved, endorsed, or connected to the real frugal-horn.com Frugel-Horn designed/developed by Scott Dave, Chris.

Hi all! I'm going to be looking for help troubleshooting my Elekit TU-8200, built in 2016. I'm not much of an audiophile, but I like building things and I've always been pleased with this amp.

Cheers!

Chris

Probably a trivial question, but it seems odd to me. In datasheets and other sources, it states that line levels are either 2Vpp or 2.5Vpp for consumer, and 4.5Vpp for professional line levels. The standards state consumer levels as 894mVpp (-7.78dBu) and professional as 3.472Vpp (+4dbu). There's also a "standard" called "semi-pro" that seems to be anything in between.

Maybe those non-standard standards where devised to prevent clipping and where intended for inputs only? If so, using those levels as outputs, as they often are, defeats that purpose.

Other than the ARD standard (4.384Vpp/6dBu) which appears to be strictly adhered to, there are some insane nameless standards for some power amplifier inputs, ranging from 5.515Vpp (8dBu) to 34.732Vpp (24dBu)!

Can anyone enlighten me?

Hi,

I have an option to buy a pair of secondhand Hawthorne Sterling Silver Iris speakers. To me, the treble looks very rolled off and I read mixed reviews on the web.

Should I proceed with the purchase or will I be disappointed?

I've often considered OB's but the cost including shipping to the bottom of the world is large so this pair of SSI's is my only practial option to owning OB's.

Thanks for any comments
Andrew

I have an older model NAD C542 that I have changed the optics/ribbon cable and it's back working again. The issue I am seeing is that the temps on the caps and I believe transistors are running at temps over 125*F. I believe they are part of the PS? Is this normal when a disc is being played? Perhaps I should change out these caps and transistors? Any help would be appreciated! Thanks 🙂

I have been using two of these vented 6.5 cu. ft. subs with my stereo/home theatre system since 2000. While they have been re-aligned since then, they are big and they are not pretty. I plan to repurpose these 'classic' drivers in a servo-feedback design or die trying. 🙂

I'm servicing a MACKIE PPM 808M that channel 1 doesn't work but channel 2 is just fine. I've determined the input op amp (U3A - NJM4560M), is bad. This is the input op to the power amp board from the mixer board. Of course the part is obsolete. Anyone have any recommendation on which of the following similar parts I should use as a replacement?

NJM4565M
NJM4580M
TLC272BCPS

Also, how important would it be to replace the good NJM4560M input op amp on channel #2 with the same new op amp part number that I'm using in channel #1?

Hello all,

I'm not much of a DIY person when it comes to audio (or anything else in fact) but do have a love for music, mainly jazz and a sizeable vinyl and cd collection. Have always been listening to solid state, except for a little Musical Fidelity tube box that is now idle. But I have always been interested to learn about the magic of tube amplifiers. I have recently pulled the plug an bought a DIY amplifier from the Dutch version of Craigslist. Now in need of some advice on how to connect everything as it came without cables.

The gear in use right now: Linn LP12 or Rega P25 => Audio Analogue Bellini => Musical Fidelity P270 => Jamo Concert 5. I still have some other gear, part of it set up at my girlfriend's house.

Vincent

...and in addition to being ultra-low distortion, it is low cost as well. The idea was to use high-impedance DHTs that you can pick up for significantly less $ than the good low-impedance triodes, and a cheap input tube. I also used an inexpensive Edcor 5k:8 25W SE transformer. Nothing exotic.

I ran 520V for B+ and 100mA quiescent current, which gave about 19W output at onset of clipping (still 0.3% distortion, but rising very steeply after 19W).

My output tube is an 826, a 60W high impedance transmitting triode, but this approach works well with pentode output stages as well. I actually started this design with 811A in mind. Whatever it was it needed a thoriated tungsten filament, that's for sure. If I had it to do over again, I wouldn't use the 826. Too many NOS tubes are gassy, and without getter material on the inside of the glass you have no visual clues that you are buying a bottle of air. I had a very high rate of returns when purchasing my small stock.

Why call it Corona? Well, the output tube plate, when viewed from above reminds me of the sun's corona. That and the virus by the same name gave me a lot of extra time to work on this.

I'll follow up with posts on theory of operation and detailed performance tests, but here's the simplified schematic and a photo of the amplifier itself to start.

I'm a new member to the DIYAUDIO family. A little about myself, I'm located in southern California and have built many DIY kits over the years. Cabinets from Jeff Bagby all the way to some big Troels Designs. Just recently finished the DTQWT 212 MK III built from all 24MM thick baltic birch plywood. Those cabinets were insanely sturdy.

Hello DIYAudio Community,

I’m excited to join this vibrant community of audio enthusiasts! My name is Ali, and I’ve always had a passion for vintage high-quality sound systems. I am particularly interested in audio restoration, as I am currently working on a project related to it.

I’m looking forward to learning from all of you, sharing my own experiences, and contributing to the discussions. Thank you for letting me here, and I can’t wait to dive into the world of DIY audio with you all!

Ali

Hi. I joined this forum a while back to learn and research but I am finally getting around to designing and building my truck audio system. I have a 1981 Chevy pickup with very little space but I want really high quality sound. Many years ago I had a 91 Mazda MX6 and I designed the sound system so that I could turn the volume really low or really high and it would always sound the same and it did not hurt at any volumn. I like to be able to hear everything and have it really loud sometimes. I love almost all types of music except I don’t get jazz, opera, or really heavy thrasher metal, sorry. That is what interests me.

New here....having channel/power supply issues with amp and/or graphic EQ. Hoping to gain some knowledge and suggestions to correct the issues. I regularly loose left channel....if I partially unplug the EQ (Pioneer SQ-550) to a half-way loose-ish insertion I can regain stereo. First guess is bad power cord, but I'm no expert. Looking for other thoughts, recommendations and/or actions to take to correct the issue.

Hello,

I am a new member of this forum. I come from midwest United States. I've been interested in electronics since grade school. I've worked as electronics technician since mid 1980's. I'm pretty much retired now but still tinker around with miscellaneous projects. I've just recently become interested in audio electronics.

I am a career electrical engineer in the area of medical instrumentation and imaging system design. I have retired and now have time to put my electronics lab back together and spend some quality time with electronics. I have always had a passion for audio amplifiers, through Heath Kits I built at an early age. and have decided to take on designing an audio power amplifier for use at home. I have been reading as much as I can, simulating various designs and look forward to interacting with members in diyAudio on questions I have.

Greetings to the Forum.
My name is Michael, I am from Arnstadt, Germany.
Working as technician in semiconductor industries as reliability engineer.

20 -10 years ago i was interested in car audio an hab build some systems into my cars. After some years of nothing i had started to build "quick and dirty" a 2-Way aktive Speaker System from some leftovers that a had found in the cellar.



My interrests are in building LS-Systems and new to me electronics like amps and pre amps.

Hello! I am currently building a soundsystem in the southwest of the UK, we have small beginnings but I am building towards a system with XOC TH18 subs, cubo 15 kicks, and MT121 mid tops to play a mix of genres, but mostly tekno, jungle and dub. I am also a DJ and producer so owning a soundsystem has been a goal of mine for a while now. I am new to all of this, having only started a few weeks ago but have been a lurker here for a while, looking to use this great community as a way to gain more knowledge and know-how from more experienced people.

Cheers!
Marley

New to this group, obviously. How I got here? ChatGPT. Why I'm here? I purchased a Kenwood Basic M2 in Japan in the early 80s to drive my Sansui PM-C200s (only released in Japan). Long and short of it is, sometime in the late 80s I shorted a speaker output, damaging the Sanken DAT transistor for that channel. I had it repaired at a stereo shop and it worked flawlessly for another 10 years before it happened again! At that point the entire setup went into the attic. Fast forward, my daughter developed an affinity for vinyl. We began buying old vinyl together at sales, used stuff stores, etc. Now I need something to play them on. So I pulled the old setup out of the attic, including my JVC QL-Y66F turntable. Now I need to repair my M2. I do have a smaller Kenwood amp in the interim but it does not compare to the M2. So the obvious question is... Is there an alternative to sourcing Sanken DAT1521N and DAT1521P transistors besides used on eBay? I know the drill. They were a specialty product produced for Kenwood and only used in the Basic M2 and Basic M2a. They have been out of production for decades and no data sheet was ever published. I am adamant about repairing this beast. Any insight is welcomed.

I am going to use a couple of 266N12 Hammond transformers to power some Rod Coleman Raw DC modules (for his V-9 DC modules). If I want to twist the secondary leads to minimize hum, I think I want to twist the Blue with the Red and the Grey with the Yellow. Does this seem correct to minimize hum from the wire pairs? I want the parallel configuration.
Thanks
Dave

I’ve seen more than one person assert that you don’t need expensive drivers to make a really good MEH. I have no reason to doubt that, but what if you wanted to simplify things by just making a 2 way MEH, but you also wanted it to be full range ie no subs required. There is at least one mid/ woofer which seems not only capable of covering say 30hz to 1000hz but of doing so with exceptional performance. I am of course talking about what may be the best driver yet produced, the Purifi 10”. Yes its expensive, but I’m wondering if you could make a really great sounding full range MEH with just one Purifi 10” + CD per channel and hence save on buying multiple other mids and woofers ?

There are plenty of experienced MEH builders of this parish and I’d love to hear their thoughts on this.

Hi everyone, I want to share and hopefully get some inputs/feedback on my first two-way design. Please feel free to give any notes/pointers on what I missed.

Background
I've been lurking this forum for years and has been fascinated by the design work of all the people here but never pulled the trigger on doing a build.
And now it's the start of a new year, I decided it's time to try and do a project.

I've set a few priorities for this project:

1. 2-way design - I looked at this project as a learning experience and I think that I would miss out on the crossover design aspect if I were to do a full-range (which I believe is a very good choice for a first build for most people)
2. Ported enclosure - similar to 1st point.
3. Low cost - Since this is a first project, I don't want to spend big, but I also don't want it to be a very low quality build.

As for measurement, I know that a lot of people think that doing a design without measurement is only a waste of time (which I understand) but for this "kickstarter" project, I decided to hold off on purchasing measurement gears as the next step in my journey, just to have something to listen to at the end of the day.

Driver Selection
As for the drivers, the main considerations are availability and cost. Due to the fact that I live in the country where SB Acoustics are manufactured, it is pretty easy to get an SBA Driver.
I've been reading other people's designs with SBA drivers and I've read a couple of times that their published specs are close to real measurements, which is good for my non-measurement approach. Considering the low-cost target, I've went with their entry level 4 inch PFC series SB12PFCR25-4 and SB19ST-C000-4.

I use VITUIXCAD for every step in this design phase

1. Enclosure Design
I've inputted the parameters on the Enclosure Tool and come up with the tuning below, then I exported the SPL and Impedance



2. Baffle Dimensions
For aesthetic purposes, I try to get close to 1:1.62 for the dimensions, and considering the driver frames, I've came up with below design



3. Taking out IEC Baffle from Manufacturer Traced SPL
I would not go into details, but basically I followed the "design without measurement" guide on the stickied thread.
In summary:

1. Trace Woofer Manufacturer data using "SPL Trace"
2. Model an IEC Baffle diffraction response using "Diffraction" tool (Important note: SBA data is from 31.6 cm mic distance)
3. Take out IEC Baffle from traced SPL using "calculator"
4. Do the same for tweeter

As a result, we get the half-space response.

4. Simulate On-Baffle Responses
For the tweeters, I used the diffraction tool with the baffle dimensions above with a 1000mm mic distance on-axis, import the half-space response, and export the 4-pi response with simulated off-axis responses. (which is very not ideal from what I understand, since there will be a lot of uncertainties occuring in the off-axis, due to dome design, etc, CMIIW)

For the woofers, there are a few more steps I did:

1. I modeled the baffle and driver location according to drawing above, with the same settings as the tweeter (1000mm, on woofer's axis)
2. I exported out the raw diffraction/bafflestep response
3. Import the half-space response of the woofer
4. Export the full-space simulated response.

So we get 2 exported response (raw diffraction and simulated full-space with traced SPL),
Using the merger tool, I imported the exported SPL response from enclosure tool and set the raw diffraction response from Diffraction tool as the LF part.
The HF part is the exported full-space woofer response (with the traced SPL) from the diffraction tool.
Then exported the merged response



4. Main Software Page
On the main software page, I imported the following as my drivers:

Woofer
SPL - Exported from Merger Tool
Impedance - Exported from Enclosure Tool

Tweeter
SPL - Exported from Diffraction Tool (full-space on-baffle response)
Impedance - Traced Manufacturer Graph

I set 17mm as the z depth of the woofer (I've seen this number on another person's project while lurking, but can't seem to find the exact page. I believe it was acquired through the late Jeff Bagby's technique to find acoustic offset), and -105mm as the y offset.

5. Crossover Design
The impedance peak of tweeter is at 1khz, and the woofer's response started to become messy around 4khz, so I decided to aim 2-2.5 khz as the crossover point.
After trying out and messing around, here is what I came up with.




6. CONCLUSION
Now what is remaining from me is to get any feedback from the forum, is there any steps I might have missed? Or if you have any input to the crossover design, what you would have changed, please let me know, I'm all ears for any improvements.

I'm planning to start the build in 2-3 weeks time so I still have time to make corrections and any changes.

And yes, after building the speaker, it is the plan to buy a measurement mic (I'm thinking UMIK-1) to conduct a proper measurement and validation of the design, and maybe design a new crossover using measured data.

Thank you, and looking forward to your feedbacks on this.

Good Evening Everyone. So am looking for a pair of the scandinavian Audiolabs SAL08C08 6.5” inch full range drivers new or in very good condition. Here’s a picture of the drivers. Please let me know if you have them and we can work out price and shipping. Thank’s Jeff

I'm really really out of touch with the audio world, I used to have a lot of amazing equipment but as I started listening to less music I traded it all in and got a pair of KRK RP5s powered studio monitors for the computer and a pair of the KRK RP8s for movies and home theater. I would like to add a subwoofer to the RP8s and for ease of use I purchased this amp due to the XLR in/out/.

https://www.parts-express.com/Dayto...W-Subwoofer-Plate-Amplifier-with-DSP-300-8010

I'm going to make a sealed enclosure, I would like the speaker to be physically protected but I don't think a 4th order box makes sense. Outside of that I think a down firing sealed enclosure would work best if I'm not going to have the woofer physically protected inside of the box. This way I can make it an end table or something as well. Any thoughts on a woofer that would be a good compliment for the KRKs?

I was initially thinking a 10" but I want more base so then I thought 12" would work. Then I figured I would just go for it with a 15" until seeing this:

https://www.amazon.com/Rockville-RVP18W4-Replacement-Subwoofer-Woofer/dp/B00MP5J7PM/

And this

https://www.amazon.com/Skar-Audio-SDR-18-D4-Subwoofer/dp/B07J4WCL3W/

Which both seem like my kind of absurd. I would be open to some isobaric designs as well as I've found some pretty good deals on 2x8ohm 12" so I can run them at 4ohms for that amp.

Anyway, please just help, I'm not set on anything other than that amp and down firing and keeping the budget around $125 for the woofer.

Thanks in advance for any input, I just don't have the brain power to spare to research this enough to make an informed decision. I think those KRK Rokit 8s have a frequancy response of 45hz to 20khz.

Keysight DSOX1102G Repair Question

Hello All,

I have a 6-year-old Keysight DSOX1102G scope. After sitting for about 6 months in a closet I went to use it and it booted up with an error message “System Concerns Detected – P-Clock failure – The default setup was loaded.”

After consulting the Keysight website (Not user friendly) I found a reference to that problem that suggested upgrading to the latest firmware, and running “Utility > Service > Diagnostics > Hardware Self Test.” I did that, but I still have the problem, but with a slightly different error message “ System Concerns Detected – System clock is defaulted – The default setup was loaded.” The last suggestion from the website document is to try a “Secure Erase” which is defined as an “aggressive reset.” Not sure what that may mean, and I have not tried it yet.

If I reset the date and time the machine seems to work, but once I power down, I am back to “System clock is defaulted” situation
Keysight wants $744.00 for a repair.

Any advice appreciated.
Thanks
ceulrich

I have an open box Electro-Harmonix

Hi Guys,

Need help on figuring out a way to use the Sony Stereo receiver which was originaly ment for 120vac in a country where we have 220vac supply.

i asked a local transformer manufacturer and he suggested to use an Auto Transformer which has one winding.

would 50hz supply the existing transformer which is made from 60Hz and at which type of situation would the original transformer be damaged

Re winding is out of question.

all help is welcomed.

I’m interested in buying a few MPAudio / Stammheim LT3045 power supplies to complete a project. I have a number of them already but haven’t been able to source more.

Thank you.

Who has the Schematic of MusicFidelity A1000 Preamp, that's the same board as EPP150 Preamp. I am rebuilding the board, the pcb has been manufactured， but cant find any schematic and components value of it.

Well, I bought a preamp board from AliExpress, hooked it up, and was delighted with it for the last two weeks--very nice sound for the price. This morning I went to turn on the system and, though the preamp was on (the power LED is lit up), the volume was SO low even at full volume I could barely hear it, though I could hear something.... What are the first things I should do to troubleshoot what the problem is? Thanks in advance for all your help.

Just taken out from a working amplifier, if you fancy Naim amps you probably know what these are, asking price 525 eur

this is the schematic, i used two op amps (the ne5532 and the tl072) and two loads an weird 8ohm pair of iems and my hd559 the amlplifier seems to improve the bass extetion and current drive of my basic ugreen dongle and otherwise works fine but it makes a weird noise when its not plugged into anything, i sadly cant post the recording of this noise but its an high pitched noise simmilar to boiling water thats diffrent from the typical mains hum.

Hello, a bit ago the amp suddenly died when sitting at idle and not playing anything, after that when trying to power it up just pops the speakers and goes into protect.

I only have some basic knowledge of amp repair. The tools I have are a scope, multimeter, thermal probe and soldering iron.

In the amp I was able to identify 1 dead output fet (B31N20D), but I also wanna check the overall health of the amp and if everything is working like it should, as it has been repaired before by someone else.

Currently I've removed all of the output FETs for testing, it seems to power up fine, but I found that a KSP92 transistor on a card gets very hot (over 70c). Along with some other transistors on the card being about 50c.

The card:



What would be the next steps? The KSP92 isn't shorted according to the multimeter.

Some observations:
One side of the output side:
Gate: 0v (has some sort of pulses)
Drain: +64v
Source: 0v (has some sort of pulses)

The other side:
Gate: -78v
Drain: 0v (has some sort of pulses)
Source: -74v


EDIT: measuring output section without and with signal (37hz sine wave) applied
One side gate:

One side source:


Other side gate:

Other side drain:

Speaker outputs:


Edit 2:
Removed the hot KSP92, but seems there are 2 of them in parallel, so now the other one gets hot.
Measured what's going to the removed transistor:
Base and emitter: about 84v
collector: pulses

why would they be getting so hot?

Dear friends,
the voice mic on my Bose QC 35 II did mute pretty early. Only peaks were faintly audible. You cannot ajust the voice volume besides self listening. I did replace the the original board, last week , still the replacement MEMS - mic sounds awful, with a bad call-quality even in quiet environments. It sounds as if the if the noise suprression defeats the voice, even in completely quiet environments. Noise suppression for voice works indepedently from the ANC that controls environmental noise vs music. For this, condenser mics are used, see the image of the U-shaped main board. The condenser mic on the left is for picking up environmental noise for music, he part marked U500, the MEMS on the right, is for picking up environmental noise for speech. The MEMS for speech is on an extra board.
I do not know much about MEMS. There is pretty much room inside the QC 35.

I wonder if I could replace the MEMS for voice (marked MU20 6A04) with a better sounding condenser mic and, if possible, how.
Or at least replace the MEMS with a better model, though it seems they all sound pretty much the same, AFAIK.
Any ideas and advices?
Thanks a lot Salar

Hi,
I would like to retrofit my old speakers by replacing the tweeter to SB Acoustics SB29BNC. Speaker sensitivities is 93dB, the crossover point is 2.5kHz (as noticed in manufacturer datasheet), the tweeter looks like Focal TC90 TD5 (6R, 93.5db).
I have no skills to use VituixCad for designing crossover, however, I have .frd and .zma files created by FPGraph from manufacturer datasheet.

The original crossover is 4th order.

I didn't find a lot of projects implemented with that SB Acoustics tweeter (SB29BNC) at diyAudio forum- the one and only was by @perrymarshall .

Any help will be appreciated.

Hi all!

I'm new to speaker design as I've only ever built kits in the past.

Like many before me, the TechIngredients Voigt pipe youtube video piqued my interest in Voigts.

Unfortunately, no frequency response graphs were published for it and so I decided to try and model it to see what it might be like.

I am new to hornresp and would like some guidance on whether I have set it up correctly. Based on the thread "Voigt Pipe Design", I think I should use direct radiator, transmission line, offset port, 3 segment, parabolic in input wizard.

Attached is my exported Hornresp record. I have also attached the driver spec sheet, and the speaker diagram from TechIngredients.

There's a missing dimension regarding the height of the port. And rather than using 9.75" for the port width, I decided to use 10.625". I assumed the height of the port to be half the width of the port, hence in my sim the port is 27cm x 13.5cm.

I tried to draw the internal cavity within the cabinet walls in order to calculate the areas at the different sections. S1 = 1.9cm x 27cm, S2 = 21.4cm x 27cm and S4 = 37.5cm x 27cm.



I've no idea how to set L34 hence don't know what the right S3 would be. In the attached record, L34 is equal to half the port height. But doing so makes the schematic diagram look like the port extends beyond the "horn"?




In any case, what my input is like right now is:



Any guidance on how I can improve my inputs would be much appreciated!

Hello all,

i looking to make a secondary system to put in my office. (i spend many hours) actually i have a pair of chr70 in stock i find them not very good against my MAOP10 and SB20
when i see the money i have put in my sb20FRPC30, it's wonderful even if the maop10 are better
the idea is to find like the sb20 something with a wonderfull price quality ratio.
i have seen aiyma drivers wich are cheap but i have never listen
i would like to make a low volume 2-15 liter internal boxes, or a mini onken or an affordable waw
What can you advise me?

SOUNDSTREAM OLD SCHOOL AMPLIFIERS
Hello, my name is Wade Stewart. I am the engineer that designed and manufactured all of the Old School Soundstream amplifiers and crossovers from 1981 through 1998, all REFERENCE, CLASS A’S and old RUBICON amps. I am here for any discussions, questions or any other need you may have concerning old school Soundstream amps and crossovers. I also offer Schematics, Owners Manuals and Repair of any older Soundstream amps.

I've started my Half Changs. I'm using 18mm "maple/birch" ply that I found at my local Lowes. It turns out that the ply has a birch veneer side and a maple veneer side . The birch side is very erratically figured so I'm going with the maple side. The drivers will be FE206s - that pile of blankets in the background covers them as they are burning in.

As you can see, the cabinets are all cut and the driver hole has been routed. I'm waiting on the delivery of a 30º chamfer bit I ordered from MLSC to finish the holes before assembly.

That gives me time to start asking questions and soliciting advice. Specifically:

- Damping - right now I'm planning on damping the rear, top, bottom and one side of the chamber to start. I have some polyester batting but was intrigued by the use of cork in the recent PAWO thread. I'd appreciate any advice/opinions about my damping locations and choice of materials.

- Bracing - I'm planning three internal braces. One horizontal offset behind the speaker, another window brace a little more than half way down the chamber, and a vertical brace from the lip of the vent slot angled up to the front (like Marce used in his Curvy Chang). Should this last brace be offset or centered? Again, any comment or advice is welcome.

- FE206 prep - the drivers already have about 36 hours of burn in and should easily have 100 by the time I'm ready to mount them. Dave has told me that he's now working on a 2nd gen of 206 mods (EnAbl, etc) so I am holding of on any intense mods right now but will be adding duct seal to 3 of the 6 arms and a felt pad to the rear of the magnet. It would vastly improve the WAF if I could color the cones flat black or very dark brown, Dave has indicated that his new mods may allow black gloss acrylic in the final stage and though I'd prefer it not to be shiny, I might have to settle. Has anyone out there successfully dyed or stained Fostex cones and dark color? And, if so, how? Scottmoose has suggested ~4 ohm series resistance so I will try that, also.

Work, family and waiting for the router bit will mean I won't get back to these for a few days but I'll post again once they are partially assembled and ready for damping, etc.

I'm working with a Hifonics Zeus 3200-1D and I'm searching for illustrations and data sheets for this amplifier repair project,any info will be greatly appreciated

Good morning everyone.

I want to preface that I have already done a lot of searching and reading on this subject but obviously quite a lot was over my head and there is incredible abundance of information to sift through. So I do apologize for asking something that is well covered and likely well understood by most members. Thank you in advance.

On to the situation. Long story short, I've always had a huge appreciation for music but never had the budget for a high quality setup so I have mostly stuck to midrange headphones and vintage scores from CL and the like. This has been adequate so far and has greatly surpassed what's available to average consumers at a reasonable price. My daily driver for the last 8 years or so has been a 1968 HH Scott 2550-W "Scottie" with its proper enclosures that I scored for $50. The drivers were smoked when I got it so I grabbed some 6.5" paper cone boses from the parcel shelf of a Mazda Millenia when I was at a junkyard and by mostly luck, these have been a great fit for the system. Its a bookshelf SS unit so I know it's not creme de la creme but it does sound great to my ears when placed well in the right sized space. The highs roll off a little early and bass extension isn't anything to write home about but it does blow the doors off what most average people would consider "quality sound" and is very pleasant to listen to for extended periods.

All that being said, the unit just runs out of steam in a larger space. My SO and I recently became home owners (finally, hooray) and I now have a much larger space that I need to fill with quality sound and the shortcomings of my setup are more apparent than in the past. I know that replacing a 10wpc with a 7wpc amp for a larger room, is a little backwards but I'm hoping with high sensitivity drivers and well designed enclosures it will work out how I am imagining.

So for amplification I'm planning on a cheap chinese SE EL84 unit. I know that I love the tube sound from a couple guitar amps that I have and I'm ready to splurge a little bit and dip my toes into the water. The unit in question is a Reisong A10. They are absolutely terrible out of the box with nearly 10% distortion at 1w output but with some simple modifications they can perform well up to 6-7wpc. I know this is a gamble but after watching Skunkie Designs youtube series fixing this amp, I am pretty confident it will be a good performer afterwards and a risk I am willing to take. I'm new to enclosure and amp design but I'm very handy with a soldering iron - everything from microsoldering on phones to building LED grid arrays for aerial advertising.

My room setup is funky. The main listening space is 14' wide by 20'ish long with a vaulted ceiling starting at 8' high on the left to 11' on the right. There is a large opening on the right side of the room that goes to my kitchen and dining room and would like to be able to pass music through to enjoy while cooking. Not ideal conditions but that's what I'm dealing with. I would like the enclosures to be close to the wall. I also know that I much prefer paper cones compared to other construction methods.

Given my constraints (full range, open sound stage, good dispersion, high sensitivity, paper cones, budget friendly, placed close to wall. needs to fit in with MCM furnishing) it seems to me that a Pencil setup with 4ish" drivers could potentially fit the bill. I have read through some of the blind driver comparison threads to get an idea of what people like subjectively and to then look at the specifications of said drivers to try and find a fit.

First up are a couple of Faitalpro offerings.

The 3" 3FE22
Pros - Very cost effective, good sensitivity, excellent off axis FR.
Cons - Bass rolls off quite early at 250hz and without a tried and proven pencil design (that I could find) for this driver I wouldn't know where to start dimensions wise

The 4" 4FE32
Pros - Cost effective, good sensitivity, very good off axis response, good response down to 150hz
Cons - off axis performance slightly reduced compared to 3FE22, same issue of enclosure design

Then there are a couple Mark Audios, the Alpair 10p or 12p
Pros - Proven, available Pencil enclosure designs, highly regarded by the community for quality etc
Cons - less cost effective, less sensitive, less off axis performance and they are apparently intolerant of poor amplification (I hope for this to be inconsequential but remains to be seen)

So long story short I guess my questions are:

Does a pencil design suit my use case? Am I on the right track regarding driver selection? If not, what would you suggest? Is there a good pencil design available for the Faitalpros?

Thank you all, this site has been a great resource so far and thank for taking the time to post on here, it has been immensely helpful already.

Hi from Christchurch, NZ. I'm trying to be retired from electronics design but I've got to keep my brain ticking over. I am here due to finding a very helpful post describing how to fix the problem with my Keysight oscilloscope. Perhaps I may be able to return the favour by sharing my wisdom.

Hi all

New here and hoping to start a build for 2-3 subs with your help. Have build subs before, its not the skills that I need help with but the technicalities.
My goal: improve my music listening experience A LOT!

Already have my first post for the DIY / subwoofer forum ready 😎

I have a pair of these beautiful 2" Ceramic drivers. I mounted one of them in a box, tested it and used it gently for a couple of days. It did not fit the design so now I'm selling them as I don't have any project to put them in and I'm getting rid of some stuff. The driver measured spot on to the advertised specs and sounded great when I briefly listened to music through it (with an active crossover slope of 24db an octave at 800HZ). So you would be getting a brand new pair. I also have the square cell adapters for them, but those were never used. I will throw them in.
https://www.madisoundspeakerstore.c...cuton-cell-c51-6-286-2-ceramic-dome-midrange/
https://www.madisoundspeakerstore.com/midrange/accuton-square-cell-adapter-for-c51/

I'm pricing the pair at $1,200 (plus shipping) but I am more than willing to consider trades for woofers, mid ranges or tweeters so please feel free to ask if you have something around. I tend to use Scanspeak and Purifi stuff.
I am located in Southern California near Temecula
Cheers!

Looking for blue heat shrink if anyone has some to spare. I messed up my Mouser order this week.

3/16 in blue.

If you have something, please PM me. I'll cover postage and pay for a few inches. Located in USA.

Thanks

Hi!
I'm trying to find out what is wrong with this amplifier. It works fine for some 15minutes, then I can randomly hear some sharp "pops" from right channel. This popping sound is getting louder and louder and finally right channel gets hot and there is lots of DC at output. It burned one of my test speakers. I resoldered the amp board and changed 4 zener diodes (16volts and 39volts). Did not cure the problem - and now im using dc blocking caps at output to prevent any speaker damages.

Anyone familiar with Levinsons and such a problems?

Best regards.

Hello every one, I just joined. Thank you very much for approval or joining member here. I'm just started built and upgrade my tube amplifiers. I look forward to future interesting items in here. Thank you again for everyone and Happy holidays!🙂

Hello, i designed and built this +/-90v smps that supplies a class D irs2092s amp. The smps not only has an isolated +/-90v output, but also an isolated +5v output thats supplies a bluetooth module, connected to the irs2092s amp audio input.

I am having startup issues, that i hope someone can see the issue or solution to, that i will explain:

If i turn the bluetooth module on with an external supply, connect to it with phone, wait a few seconds and then turn the smps+amp on, everything is fine and plays nicely.

If i connect the bluetooth module to the smps +5v, and turn on mains power to smps, the irs2092s amp starts up but makes terrible noise on the speaker output, gets hot, and draws loads of current…? Sometimes the module even breaks.

The only way i have got the system to work at the moment is by having the bluetooth module already on and connected to a device. Im not sure why.

I need to design some sort of staggered startup system, this js my idea but im not sure if it would work:

I could use an rc timer that runs on the 5v, which turns on two relays after ~10 seconds which lets the +/-90v flow to the irs2092s.
This way, the bluetooth module is already on before the irs2092s.
Would it be safe to suddenly relay the irs2092s with +/-90v? I assume the modules onboard capacitors would charge up very quickly.

WiiM Pro Ultra room EQ for my workshop. I turned the sub bass off for this. Dogs weren’t happy and legged it out of there when it played the tones. Maybe I had the volume too high ha ha (this for the B&W 703s). There’s a big refinance peak in the room at 150-200 Hz which is really excited at high volumes - the room is a bit small for the 703s - the KEF LS50s are better I think with the sub bass. I’ll have to try those later.

As requested the 1et400s buffer for the 1et7040sa.







With below the gerberfiles.

Hopefully a quick question.

Regarding the “distortion adjuster” (for want of a better term), P3, on the front end board of BA3.

Is the absolute value of this pot critical? I forgot to order some 100r trimmers (as per the schematic). I have a few 200r trimmers though. Would they work just as well?

This is the tube heater supply for a phono preamp I built many years ago, the LT1084 is bad and I would like to use LM1084. The load is 1.2A. I don't see a problem but want to make sure I didn't miss something. I am also asking as a general question as I tend to build similar power supplies.

Hi,

I'm building a gainclone amp, and I need a rotary selector to switch between sources. I have three inputs to the amp, and I bought one of these:

Rotary Switches : Rotary Switches : Maplin Electronics

I got the 4-pole 3-way one and that's fine, but will this switch do for audio?

Can you recommend something else I can use for this purpose? This is my first attempt at something like this and I'm not sure if this switch will work or not, I'd like to be sure before I solder everything up.

Thanks,

Looking to make a passive input selector for multiple RCA inputs into a single preamp input. Would like 4 input selections. I just dont understand the nomenclature enough to select a good switch on my own. If someone has a link to an acceptable switch I would appreciate it.

My pair of the large ESS AMT-1s arrived and I am seriously impressed by them! I did only some quick and dirty measurements and they are flat and very low distortion, I guess they will sound great.

I will report my progress in this thread - trying out different combinations with direct radiators, paraflex and horns and ultimately a synergy horn with them.

Dear diyer, a silly question: is it possible to insert vertical radial power resistors instead of axial ones on the emitters of the final bjts?
Like this:

Same technology certainly: wirewound. In my opinion there should be better heat dissipation, as well as better distribution on the PCB (because developed in height) . I've seen few applications with radial power resistors, I don't understand why: do they have contraindications?
Thank you for your usual availability. a good day everyone
Ros