Hi,
I have the ALPS27 Motor Potentiometer that I bought some time ago. I got it with a circuit for the remote conrol. But Ihave been looking all over to get a circuit diagram so that I can determine exactly what the J3 connector is used for. But I can not find anything. Any help with this is greatly appreciated.

I've a DSL710 that has the usual no disk issue. It's been written that it's really a detector issue, but no matter. After opening the unit to my surprise I to found a HOP-1000 laser instead of a HOP1200s that I expected and had previously ordered. Can someone confirm or dismiss that the two lasers are interchangeable,? The player at present plays factory CDs but no CDR or DVDs. So most certainly it's the laser unit....

Hello,

Name is Chris and I am working on taking a 1950's Zenith console and replacing the long-dead guts with newer (albeit pretty cheap for now) components. Keeping the the existing speakers but replacing pretty much everything else.

I will be posting in a few areas looking for specific help.

Thanks in advance!

Good afternoon everyone. I sold or gave away all of my programs but, bass box pro. Am looking to make a slot vented box for a pair of Mark Audio drivers I’m very fond of. The CHN-50s. I believe they are the best fullrange driver out there for the money hands down. So what program can I use to get the best results? Sorry if this has been asked before? Jeff

Whenever visiting DiyA, the first thing I do is scrolling to the bottom of the page to set the theme color and time/date format to my liking, but if I decide to log in and after a while log out, the theme color and time/date format cookies gets deleted at log out, would it be possible to exclude the following two cookies from being deleted at log out:

• diyaudio_language_id
• diyaudio_style_id

I have tried to use couple of cookie extensions in my browser and lock the cookies but it doesn't always work.


BTW, the placement of these theme color and time/date format settings at the bottom of the page and the behavior is rather annoying and frustrating when one have to reapply these setting several times a day, here's what the procedure look like right now:

• Scroll all the way down to the bottom of the page (or use "End" button on the keyboard)
• click on theme button
• page represents the available styles in a pop-up window, but... AT THE TOP OF THE PAGE far from the bottom
• ok, make a large mouse movement to the TOP OF THE PAGE to select the style...
• page reloads and GOES BACK TO THE TOP, hey I am not done yet!!!
• ok, one more round of this nonsense circus... scroll all the way down to the bottom of the page
• ... click on the "YYYY-MM-DD / 12-hour clock" and select the one used in our region.

...rinse and repeat...........

• page represents the available styles in a pop-up window, but... AT THE TOP OF THE PAGE far from the bottom
• ok, make a large mouse movement to the TOP OF THE PAGE to select the style...
• page reloads

Not fun.

Hello all. David Seymour here. Long-time stalker, first-time poster. My current project is a bass guitar combo amp using this Sunn 200S preamp from EffectsLayouts.com coupled into this cheapo Chinese mono power amp stage. Meant to be small enough for solo practice and lugging around, but powerful enough for small ensemble gigs, maybe even with a modest drummer. Heatsink, cabinet design, and 8Ω speaker selection is done, but I need help figuring out the power supply. I'm definitely not a qualified electrical engineer. I'm handy with schematics and a solder station, but I know better than to mess around with power mains.

The Sunndering preamp is designed for DC 9V, presumably 500mA is plenty. The Chinese power amp PCB says it accepts wide power supply range, dual voltage DC +/- 20V-90V (not sure what that additional 12V input is on the bottom right.) I'm thinking 200W, 45V or 60V would be best, right? Trying to keep costs down; it's a bass guitar amp, after all, not a HIFI or audiophile grade application.

Is there such as thing as a ready-made solution for this? If not, can anyone point me to some existing DIY solutions, schematics, BOMs, etc? If not, who is able to design such a thing for cheap?

Thanks and cheers! 🍻

Preamp stage:


200W Power amp stage:

Longtime audiophile now venturing into DIY audio projects….

Hi guys! Are there any DIY tapped kick horn projects anywhere in the world? Or have such projects already been realized and I haven't found them? Or to put it another way: There are no TH kicks because it is perhaps impossible to construct a tapped horn as a kick horn? Or has no one tried to develop one yet? Questions, questions! I'm hoping for a little exchange of experience from the experts!

Best regards

I'm building a new system using a SEAS 4" Full Range and a SEAS 6" woofer. I'm trying to determine the point on my preamp volume control that represents enough power to blow the 4" driver (coil melt or cone damage) so that I don't get to or cross that boundary during listening sessions. 90% of the time I'm probably listening in the 65 to 85dB range, which I know isn't close to the power handling of the speaker. However, I'm sure we've all experienced a time or two when very loud is very good and inhibitions aren't properly in place. 🙄

The speaker has a 3.3ohm voice coil resistance. Handles 40W long term and 100W short term. If I use the equation of W = V-squared / ohms then it looks like somewhere around 11V amp output is the stopping point. I'm wondering if I can put my voltmeter on AC mode across the speaker terminals and figure out where the volume equals 11V and don't exceed that number on the preamp. (I also have an oscilloscope if that is a better tool to use.)

I'm asking in the Class D section because I'm using an ATI AT524NC amp that puts about 350W into 3.3 ohms at full tilt.

This amp plays good audio but sometimes it will just start clipping.It does that even when there is no audio playing.

Any suggestions?

This amp power up has rail and regulated voltage.I drive a signal in the amp but am not seeing no oscillation on the outputs.Driver ICs have supply voltage.

Any suggestions?

Hi. I don't mean to sound like a Gil Scott Heron song, but I'm new here, will ya show me around?

I'm tying to get the maximum level from a Source player that has both options of RCA's and XLR's outputs.
I would like to unbalance a balanced source, does that mean a straight short between pin 1 and 3 or ...

Decoupling capacitor between pin 1; Negative and pin 3; Gnd ? If so what type, material, size?

I'm used to studio gear and this Source player is a quasi balanced device, too sensitive for my likings.

O/C between 1 an 3 results in buzzzzzz

David Seymour here. Long time stalker, first time poster. I studied music production and audio engineering many years ago, am just getting back into it. I've designed or modified many stompbox circuits, mainly bass distortion, octave fuzz, reamping. Working on a few more primo balanced mic/instrument preamps. I'm a bass player, but no longer have a bass amp, so I'm currently building a combo amp from components designed by smarter people than myself. I need help with the power supply section, which I'll be posting about shortly.

Thanks and cheers everyone for generously sharing so much expertise!

Hi all,

I guess I am posting this because it is a requirement to post.
🙂

Anyway, I never posted anything since my skill sets are still very novice and I never really had a question or challenge that I needed to seek an answer for. However, that is changing so I wlll be posting my question shortly that I hope someone can answer and lead me down the right path.

Dave

Hi everyone, and nice to meet you.

My name is Jan Zuidersma, I am from South Africa.

I have a little mix of vintage hifi equipment, and I also enjoy doing DIY audio a lot.

Looking forward to learn and share with you people.

Hi. I'm from Ukraine. I need help finding some service manuals.

I'm looking for recommendations for a quadrature rotary encoder with detents that has nice high-quality feel. Ideally, I'd like somewhere around 16-25 steps per revolution.

I've used the Bourns PEC11 series previously, and these work ok but feel kind of cheap.

Anyone have any experience with Nidec or Grayhill, or have other recommendations? I was looking at the Nidec REC20-25-201-1.

Thanks.

Hi DiyAudio community !

I’m really happy to finally join this forum after countless hours of reading fascinating threads. This place has been incredibly helpful as a guest, and I can’t wait to get involved as a member!

I work as a fabricator in metal working field, in a small but cosy workshop. I mainly work around art work production and design for other artists. As well as this exciting job, I'm interested in diy practices and open design ideas.

Last year, I discovered the joy to have a listening room. After a lot of different vintage hifi setups, it was time to build my own !I’d love to share more about it in a dedicated thread.

✌️

We got a new sky glass gen 2 tv on saturday and it seems that the only audio output is through eARC and my dac doesn't have a eARC connection. For using normal 2 channel stereo would it affect the sound quality going through a device that enables me to go from a eARC cable to a optical cable.

Hi everyone..I have been trying to find the volume control for the headphone amplifier output for Philips CD/Magnavox CDB 650..
The control is Alps ZV103A...I need to know where to buy it..Needing 4..
Thanks.

dynaco sca35 - having an output transformer rewound - should i do both?

I started this thread to post the spreadsheet that I use to keep track of vacuum tubes that I have dealt with. I keep it updated as needed. I have posted older versions on diyAudio before, but they get lost in the crowd.

I have used this spreadsheet for years and have fixed several mistakes. I can't guarantee that there aren't any more. Use at your own risk, and consult a tube manual if in doubt.

I made this spreadsheet for my own use over a period of at least 20 years. It is not always consistent or complete since it was intended for my own use.

If there are any questions, requests, or comments feel free to post them, especially if you think that there is an error.

I'm sure that there are more goodies hidden in a dark corner of my 20 TB NAS drive box. I'll add them as found.

Hello,
I'm a novice at speaker enclosure design, so please forgive me if this is a dumb question. I'm designing an enclosure for a pair of small (3.5") full range speakers to use in a bedroom/office setting where high volume is not needed. I currently have the speakers in enclosures with a cylindrical port sized to achieve what seemed to be the lowest I could reasonably go without getting huge peaks and valleys in the transfer function curve using an app I found online.

While I like the sound of the current setup. I want to change some things to improve the overall setup and want to try to improve the bass output while I'm at it. Now, I'm looking to construct a multi-chambered enclosure with the full range drivers on each end of the front baffle and a 3" mini subwoofer in the center. To get the lowest bass output I can with a flat transfer function curve with the sub I'm considering, I need a very lengthy port that will take some creativity to build into my enclosure given the size limitations I have placed on it. I'm looking at using a labyrinth port design to achieve this.

After running different port scenarios in my app (single port, multiple ports all of different sizes, lengths, round and rectangular), I've concluded that a single port out of the speaker chamber gives me what I think is the best, flat response until it hits a steep drop off at the low frequency end. The geometry constraints of the overall cabinet makes it challenging to fit the labyrinth port in the box efficiently.

Finally to my question. Is it acceptable to have a single port out of the sub chamber, then Tee it a short ways downstream, then have two runs switch back and forth, terminating in two outlets? Can I count the length of port tubes on each side past the Tee toward the total length of port, or does the Tee somehow reduce the effectiveness of what comes after it.

Thanks for any advice you can give.

After some experimenting I'm left with some spare M2x input stages I'd like to sell.
All these were in my amplifiers working before their removal.
I have four IPs9's and two Cedarburgs v2.

Asking $20ea. plus shipping.

Hi all,

My Rotel RA-611 produces excess hiss - enough that it's audible from across the room with the volume at zero. I believe the issue is in the Tone/Preamp section, since if I pull the connectors to the main amp the hiss is gone.

I've traced through the circuit with an audio probe and it's nice and quiet until the collectors of Q204 and Q208. From this point forward there is the loud hiss in the circuit. I thought it might be the 50 year old transistors, so replaced the 2SC644s with KSC1845Fs, which made no difference. All of the voltages match the schematic, the capacitors have been replaced and the carbon resistors have been replaced with metal film - also made no difference.

Please find the schematic attached.

Many thanks in advance for the help!

I found a dead Krell FPB 200 on sale for cheap. The seller wrote that it goes into protection immediately.
from past experience i knew, its gotta be a short somewhere in the output drive.


what too heavy and those handles at the back make no sense, it messes up the front frace when placing it down.
the fins are also quite pointy and sharp, you cant grab it there.


So i started taking it apart.

Its well built, easy to take apart. a few screws here and there, and everything comes off in modules.

but its huge, its heavy. and its overbuilt as heck.
i mean what you need so many transistors to drive the output stage?




and its microprocessor controlled (biasing trough optocouplers that switch in and out resistors. it measured the rail and output voltage and currents at all time.




If its one of these, i might be screwed. Unobtanium TO-3's



i didnt wanna do this to it, if possible:







But after measuring several spots, i found no short.
so i kept digging, taking apart this PCB sandvich, comparing Left and Right for meter readings
and found a reading that wasnt equal on one so i looked whats hooked it to.
a shorted transistor, but after lifting the legs i noticed the short was still on the PCB

turned out to be a shorted silver Mica capacitor (1100pF)

after replacing it (all eight), it started working again!


for good measure i gave it a new set of electrolytics, the old ones where still good but the new ones are slightly lower esr and may last a while longer now.



After listening for a while.. i noticed this thing is a damn room heater.

60W in Standby!
180W when turned on..
1600W when theres a signal going in without even a load connected.. Class-A of course.

i listened a few hours and my room went to 35c.. nothing i want in my room 24/7.

it sounded good, nothing that immediately kicked me off my chair but alright for an class-a amp. may not have the right speakers for it.

i found my "jaboost" opamp-amp that ive built afterwards sounding slightly less fatiguing over long sessisons. and you dont want to leave the room afterwards.
https://www.diyaudio.com/community/...her-dont-expect-miracles.423889/#post-7929116


Its gonna find its place, someday, somewhere.

These have been unavalable for some time. It is a circuit for EQ of dipole woofers.
I am hoping someone has one they would be willing to part with.
Thanks

I have played around with similar simple circuits in the past for fun with numerous BJT Darlington Pairs as single package or discrete. Usually obtained around .0006 to .001%
1Watt THD1 using the classic 5534 as the driver. Typical expected 18 to 27 watts with op amps that you might tippy toe into the 22 volt area. ( Yeah Whatever more like 15 to 22 watts) to be safe.

A circuit design example was requested. So I made sure I was not blowing smoke up my own butt. Put together a more final circuit with hopefully real world stability margin.
Then run it up close to crest power and see what THD20 ( 20 kHz) was. Then post another sim amp that people love so much. Somebody might do a PCB ( probably not) and remind me diode thermal tracking makes everyone yell at the clouds. Until someone just has fun and is actually creative enough to build one. Woo Hoo

I like using diodes sometimes, because its fun and also easier with op amp drivers to use Boot Strap current source for the hardest swing you can get. Maybe live the Fantasy of getting 25 to 27 watts into a 4 ohm load. It actually does swing rather well driving a Darlington pair. The simple bias adjustment circuit will basically get you going dead centered at 50%. If you want to run 85 to 100ma for high frequency numbers about 55 to 65% will do it.

Yep T0-220 package for power transistor Using 80 volt 80 watt, 50 MHz fT with around max 1 amp current expected hfe should Hold 80 to 100 and yes minimum is rated 35 to 40 like a zillion other T0-220. D44VH10(NPN),D45VH10 (PNP) manufactured currently by On-Semi



------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Bandwidth 1 Hz to 514 kHz stability phase margin 50° ( thumbnail click to enlarge)


Clipping Behavior 4 ohm load ( thumbnail click to enlarge)


No Overshoot / Gain peaking 20 kHz 4 ohm load ( thumbnail click to enlarge)


THD1 ( 1 kHz) 2.83V output 1 Watt

THD20 ( 20 kHz) 2.83V rms output 1 Watt


THD1 ( 1kHz) and THD20 ( 20kHz) with 300mV input and 900mV input 8 ohm and 4 ohm

8 ohm load
============================
300mV input 8 ohm Load 1.2 Watts output
============================
THD1 .0004 %
THD20 .003 %
============================
900mV input 8 ohm Load 11.2 Watts output
============================
THD1 .003 %
THD20 .007 %
-------------------------------------------------


4 ohm load
============================
300mV input 4 ohm Load 2.4 Watts output
============================
THD1 .0004 %
THD20 .006 %
=============================
900mV input 4 ohm Load 22.5 Watts output
=============================
THD1 .004 %
THD20 .01 %
-------------------------------------------------

Slew Rate Measured 10 kHz 10 Volt Peak to Peak , 5 Volt Peak Delta X Delta Y 10% 90% 551 Nano Seconds
= 14.5V/us Slew Rate

Hello everyone. I got an idea looking at Peter Morris PM90 speaker if it could be used as line array cabinet with appropriate waveguide, then someone has offer "half" version of it with only one 12" and I really like it.
My idea is that single 12" design tilted to side.
Like a small line array high-end cabinet with fixed angles using coaxial dcx464 on "DOSC" waveguide crossed at 650Hz, together with mb12n405 on folded horn of PM90.
It could be active powered by DigiMod 3004pfc4 using two channel in bridge 1x3000w for mb12n405 and other 2 channel 2x1000w for dcx464.

Here is the pic of how it should look being only 650mm wide, array should consist of up to 5 cabinet with 5* to 20* angle for each cabinet with all 5 cabinets making vertical dispersion angle of about 62* and horizontal, it should be about 100*.

Regarding waveguide, something similar has been used in VIO L1610 crossed with dcx464 at about 500Hz as their specs tell.

This is just an attempt to connect two designs into one from a person that doesnt have much knowledge about designing speakers, so I would kindly request a help to see if this design have any potential.

Let's assume that the dcx464 would work well on such a horn from example of the VIO L1610. What would be advantages and disadvantages of mb12n405 midbass arrayed 2-5 cabinets on each side above dual 18" subs for live sound reinforcement? Will it have same quality, coverage pattern and possible lower crossover point to subs compared to PM90 or single 12" design may not work that good ?
Volume for the 12” would be about the same as in PM90 speaker.

Hello!
Very light background in diy from building Eurorack synth modules and from hanging around with circuit bending and sound art people. Newbie woodworker, synth noodler, ex-dj, ex-concert & event photographer, hobbyist fruit and berry gardener, some sort room acoustics weirdo/nerd, wannabe dry stone waller.

I have a small dedicated listening/media room in an old wooden house with quite studio'ish diy acoustic treatment. Current speakers are my first diy speakers, B&C 15CXN76 elements in 120l (net) bass reflex enclosures (Piste15 kit by Samu Saurama/audiovideo.fi), a stereo pair of Eminence LAB12 in ~32l closed enclosure sub/low bass speakers to compensate speaker placement related problems and a Genelec 7360 to bring some roundness to the lowest half octave with nice support from the room. Livingroom has Genelec 8340.
As an old raver / dj I'm interested in "party mode quasi-PA, but HiFi" speaker builds and I'm aiming to build a small sound system for my wife's 50th birthday party, she is a lot heavier basshead than me, so I need all the Emotional Support SubWoofers.

looking specifically at Radian:

https://radianaudio.com/collections/ribbon/products/lm8k-wide-band-planar-ribbon-transducer

it says the conductor material is "aluminum foil"

but aluminum is a material that suffers from fatigue when repeatedly bent. in a planar the "voice coil" and the "suspension" are the same part - so you now pretty much have aluminum suspension. the only other drivers i can think of that have aluminum suspension is Beyma Bullet Supertweeters ...

but Beyma Bullets have replaceable diaphragms, in fact i replaced it on mine ( due to issues unrelated to aluminum fatigue ). it doesn't seem like you can replace the diaphragm in a Radian driver.

would this be a cause for concern in a high SPL application ?

does GRS planar also use aluminum foil or do they use copper ?

does it make a difference for durability ?

thoughts ?

EDIT: i should add that Beyma Bullets have recommended frequency range of 5khz and up, while the Radian is recommended down to 250 hz so it would probably see a lot more bending of the diaphragm, though that's just a guess, not scientific analysis.

I'm building a open baffle/dipole speaker and want to try a rear mounted tweeter. The problem is the only extra tweeters i have are different, similar sensitivity though. Both are 4 ohm. The amps im using are ice power amps, is it safe to wire them up in series and try it out?

Hello friends. For a long time already, about 5 years I had unfinished acoustic systems, but recently I decided to finish them all the same. The speakers consist of a bass segment, which in turn is built of a double membrane stack, each with 4 stators and 3 membranes, a total of 6 membranes and 8 stators composed by isobaric. As well as a high-frequency emitter. Everything that I do I will gradually spread here.

For me, hum and noise are the most important aspects. I may not be able to hear THD 0.1%, but I definitely can hear hum if there is any.

Below is a simple way to implement balanced input. When the resistor ratio matches between positive and negative side, it gets optimal common mode noise rejection.



I am not going to convert my amp to balanced interface, but let's see what if we use the same principle to the existing RCA unbalanced interface.
Let's replace the opamp with a power amplifier. Like this, you can see it does reject common mode ground noise.

1. Ground noise is canceled when R1/R2 = R4/R3.
2. Don't bridge the signal ground to the chassis.
3. R5 is necessary, R5 needs to be << R2 so that the negative feedback ratio won't change much when the signal ground is floating in air.
4. Be careful when adding volume pot directly to the input of the amp, it is equivalent to an out-proportional R3. The noise cancellation condition no longer holds true. The work around is put a unit buffer after the volume pot.
5. As the input impedance of the signal ground is very low, 10 Ohm in this case. I would not call this a balanced interface. It is a still unbalanced interface. However, it has the capable to reject some of the ground noise. It will be an improvement to the existing RCA interface.

PS: C2 should be equal to C1 to get optimal results. Thus, the improved version is C1 = C2 = 22u.

PPS: In some situation, it might not be easy to put extra R3 or keep R3/R4 ratio constant. For example, a volume pot. I post a compromised version at #11. Although it cannot cancel out ground noise completely, the ground noise won't get amplified, either. Thus, only the differential signal is got amplified.

It has been a long road designing the Emerald Physics 600.2SE amp, but what we have finally achieved is totally worth it and an amazing sounding amp. This amp has enough power to satisfy any speaker one could imagine or need. I want to thank Jan Hofland for his help on this project as he designed the HyperSET tube buffer that feeds the 600w class D amp the audio signal. We are now finally starting production of this hybrid amp - a 600wpc Class D amp with a SET tube buffer (E88CC or NOS 6N1P). Accepts balanced or SE inputs. Selector switch for tube or SS buffer. The sound is powerful, smooth and clean with just the right secret sauce of a SET goodness. The grip on the bass is incredible. Built in integrated logic controller for graceful startup and shutdown to allow proper tube warmup and no thump. Chassis is satin finish bead blasted and black anodized CNC’d aluminum with a luxurious feel and heft (5mm thick panels all around). Real galavanometer VU meters to show power levels and quality Neutrik XLR/TRS connectors and premium Viborg pure solid copper binding posts.





Have a listen to this amp with some Vanguard bookshelf speakers:
Login to view embedded media

Hi! my wife buys a lot of bread boards for institutions and in the last two years the quality has severly dropped. Like the holes are not clean and contact is bad and so on. Do any of you have a reliable source for good quality bread boards?
Thanks.

Hello DIYers,

I'm new to this hobby and planning to make myself a set of home theatre speakers using my 3D printer. Maybe later also a sub if need be 😉

I saw this sub/mid range woofer, the TangBand W5-1138SMF, which seems to have really deep low end. I've seen it paired with the Dayton Audio RS100-4 ("Dinas" speakers from this video).

I really liked the concept and tinkered a bit in WinISD and VituixCAD. However, now I'm wondering if there wouldn't be other options to replace the RS100-4 with something more geared towards high end and let the Tang Band do the job in the mids.
Would you have anything else to recommend? Mainly cheaper. I had issue finding something that would crossover nicely at 1 kHz or so.

Also, how bad would the distortion be if a tweeter was to be crossover too close to Fs with a DSP ? I've read somewhere that it might be less of an issue than with a passive XO.

Anyway, happy to be part of the adventure!

Intrigued by good reports (Scott Wurcer and EUVL) on BF862 JFET I also got some. The idea was to build a preamp based on JBOZ and B1 concepts with gain of 2 (enough to drive F5) and ability to drive 5K next stage impedance. Also, 6-7 V of undistorted output signal is needed.
This is what I ended with and it's all I hoped for, it sounds great, better than 2sk170 in same topology - I suppose it's due to much higher transconductance and smaller parasitic capacity. The only "problem" is that BF862 is an SMD part but that's easily cured with small adapter PCB.
This is the preamp and PSU schematic:

I've always considered 10dB as the 'nominal' value for line stage gain in a preamplifier. Does that sound about right to you?

Simple question: Why do most (almost all) negative feedback amplifiers use Miller compensation rather than lead/lag? The latter has a much flatter Bode plot of the OLG which, I believe, should increase the slew rates.

What’s the disadvantage of a lead/lag (other than the need for larger caps)?

Hi All,
Need an advice to troubleshoot my Pioneer PD-75 CD player. Unit was working fine till one day. Now, putting CD into the tray is closed and after 5-7 second the tray is opens. I opened the cover and found that the laser head is not moving to the center of CD. The lens is not lost ( this is a common problem with this players), Also, the laser head was working excellent till now. I will appreciate any suggestions.

Sioux
Here is a higher power version of Choctaw.
Output 26 Watt with +/-25VDC supply.

Bought a AVT150H
Upon first use only the clean channel worked.
Now i opening up to look at it and the TDA7293 chips have been replaced before and have failed again. One looks to have let out smoke.

I amp hoping to replace the AVT50-62-00 with a class D power section. If anyone can assist me with this undertaking.

Can these even be done? Thanks!

hi, I would like to kindly ask for any help/advice.

I have had these speakers for almost 20 years, and I'm thinking about upgrading its crossover.

Speakers are 8 Ohms and with cross-over frequency 3kHz.

I plan to use Mundorf components, 4,7uF and 10uF capacitors - I guess both are for the tweeter. These are visible on this upgrade:
I'm not sure if the existing original is the same design, I guess I will find out once I will open the box 🙂

But I'm not sure about inductors/coils. Based on calculations, I should use 1-1,5 mH inductor for the woofer and 0,4-0,5 mH for the tweeter.
I guess these values will not be marked on the existing crossover and I'm not sure if I'm correct and will not corrupt the sound.

This is how probably original crossover looks like: https://bowerswilkins.encompass.com/item/12592525/Bowers__Wilkins/ZZ10340/

thank you in advance for any input,
Tomas

A friend of mine built a tube output stage a couple of or three years ago using old radio PCBs, and it totally got my brain buzzing—I had to try it out myself. Meanwhile, I came across Pilovis’ low-voltage PL504 output stage and figured it’d be a good experiment since the plate voltage isn’t crazy high. 🙂 That’s been in the works for about a year now.

Unfortunately, Pilovis’ design didn’t really click for me, but I did get a taste of that sweet “tube sound.” Then I built an ECL86 output stage that I’m pretty happy with. It’s not perfect, but even with used radio parts it sounds decent. I put it together using Alex’s “RH universal” circuit and a switching power supply. 😉 Now I’m starting to dive into winding the output transformers…

Shorting the secondaries provides a very smooth mute with no switch-pop noise. However, is this safe for the device connected to my input? The device in question is a Shure Wireless Receiver with a 100Ω output impedance.

This keeps bugging me after seeing a video (forgot where) about how to optimize active crossovers. In it the presenter deftly uses tools to create absolutely ideal LR4 crossover slopes. My question is, does it really matter if the speaker works correctly?

Here's an example. I overlay an ideal LR4 high pass filter for 3 kHz on top of the tweeter response with a filter. In the context of the total speaker, I have the output response and phase matching I want. Is there much value in fixing the area between 2 kHz and 4 kHz so that it more closely tracks the ideal LR4? My intuition is to leave it alone, less filters is better and that there's no practical benefit in attempting to peen this curve to "ideal." Am I wrong?

Hello, I'm from China, I'm a technician a friend recommended this forum for me to know more about audio and technical issues. I'm excited to be here and to learn more

Hello,

May be this subject has already being discussed. I understand that this might be frustrating for some people to go over it again. But here is my question:-

A year ago I was trying to troubleshoot a Denon AV receiver. Denon (as an example) uses Sanken Complementary transistors. This amp is 5.1 output receiver. So I need 5 Complementary types (as an example 2SD2390 Complement to 2SB1560). Apart from being complement to each other, they have to read the same Vbe and same hFe. (Matched) I understand that. So when I applied to a store providing these, the question was " Do you want them Matched pairs ?" I replied yes.

Now I am in the process of repairing a QSC RMX2450 completely burned both channels. Measuring around, I understood that the transistors are fried, drivers, power transistors, etc. QSC uses in this instance Toshiba 2SC5200 and 2SA1943 complementary pairs.

I read in this forum that these are constructed in very tight tolerances so they do not really need to be matched and incidentally the supplier did not ask me whether I want them in matched pairs. Searched a bit on the web for matched pairs, resulted in no hits for matched pairs. However for the pre-drivers MJE15032 and MJE15033, there was a question do you want them matched pairs ?, and there was a hit for matched pairs on the web.

Dazzled !! Can this be true ?

Seems I have made a mistake in assuming I could connect my ucd250 modules directly to my Najda dsp.
The nadja has 6v outputs and approx 2kohm impedance and the ucd250 needs 6.5v, and has 1.8k impedance.
I'm assuming I need some sort of buffer stage to go between them, any suggestions for a basic buffer kit?

So I'm wanting to build my own two-way with a 15" bottom end and looking for something to get close to the venerable JBL 2235.

In Australia the SB Audience Bianco-15SW400 costs $299 has some very similar specs.

Both modelled here in 130 Liters. How does this look?



Opinions appreciated!
Cheers.

Hi everyone. XrayTonyB built a cool little tube amp kit from Douk Audio on YouTube about 4 years ago, and I want to try one myself. I haven't done anything with electronics in a while, so I want to check with someone who knows before I go messing with the circuit at all. It has two "magic eye" tubes in it that I really don't want. Since I plan to wire the kit point-to-point instead of using the included PC board for the audio portion, if I could eliminate those two tubes and the associated components, it would save me a whole lot of work.

Here is the schematic with the connections and components that I am considering eliminating marked with red. Can anyone confirm that I am not going to mess anything up in the other parts of the circuitry by doing this? Sometimes weird dependencies happen. It seems to me that they are completely isolated from everything else.

I would just ask XrayTonyB since he is a member here, but I don't seem to have the ability to send private messages to anyone. Link to his build videos: Login to view embedded media
With his few small mods, I think it would be a neat little amp for me to build. It tested good after he built it and put it through a series of tests on his bench.

Also, has anyone built this amp recently? Does anybody have one that they built recently, and if so how do you like it? It seems that current versions eliminate the loudness control that XrayTonyB cut out of his when he built it, but I haven't been able to confirm that yet.

Edit: updated schematic to show final values.

It appears the KSA1220AY parts for the M2x IPS6 boards are no longer available in small quantities.

Does anyone have these on hand in the USA that is willing to sell/share enough for 10 PCBs (10qty)? I will share the extra boards I ordered from JLCPCB and the KSA parts with others at cost.

I believe I can acquire all the other parts myself, so I just need the KSA parts to finish up a complete BOM.

Cheers!

Greetings and Good Day!

After many years, I have finally got around to finishing my 8-channel amplifier. I will post pictures soon, to aid in troubleshooting.

Components used:
SMPS: MicroAudio Cobra-S2 https://micro-audio.com/store/product/cobra-s2/
^Datasheet: https://micro-audio.com/store/wp-content/uploads/2022/05/COBRA-S1-1.pdf
Amplifier Modules (4): https://shop.icepoweraudio.com/product/300a2/
^Datasheet: https://shop.icepoweraudio.com/wp-content/uploads/2024/04/ICEpower-300A2-Datasheet-1.4_.pdf

The issue is as soon as I turn the SMPS on, it goes into protect mode.
This only occurs when an amplifier module is hooked up. It will sit, powered on with no errors if no amp module is connected. Therefore, I feel the module is sending a DCError signal to the SMPS, sending it into 'protect' mode.

BEFORE I hooked up the SMPS to the amp module, I verified all voltages:


I do not have anything hooked to the 'Basic+ Control Connector', as I am not using BTL. Perhaps I need something from this section hooked up to the SMPS?


I also am not using the 'Aux connectors J4 & J5' on the SMPS. I didn't see anything here I needed. There is a pin for FATAL (error/fail) but so does the J3 connector (and evidently it is working, as it is sending the SMPS into protect).
J4/J5 (not in use):

J3 (HIGHLIGHTED pins in use):


Perhaps I need to hookup J3:5 and J3:6 above? 'Amplifier enable (Opto isolated) E' and 'C'??? I could not find anything on the amp module that made sense to hook them up to.


I really appreciate anybody's help in advance--I'm definitely confused!

Thank you!

Hello everybody, I hope everybody is doing well. I recently purchased line stage 6sn7/300b based pre-amplifier. It uses toroidal power transformers as outputs transformers. The sound of the pramplifier as it was received was ok but not exceptional compared to the LTA pre I have been using. To see if the SQ improved I bypassed the input select rotatory switch, the balance potentiometer and replaced the remote controlled attenuator with a Goldpoint ladder attenuator, replaced the gain adjust potentiometer with a simple voltage divider circuit. The SQ has improved a good amount but not quite to the LTA pre level.
Can you advice on improving the output transformers? the ones installed are meant from converting 120/115 Volts 50/60 Hz to lower voltages for regulated power supplies. I am curious about kind of bandwidth of these transformers have when used in the audio frequency band. I guess I could buy the 2 models used and run a test...
The other potential improvement is to replace the coupling caps, installed are metallized propylene (MKP) in parallel with a paper in oil caps. All theses parts the potentiometers, selector switch, attenuattor and capacitors are common inexpensive parts.
I know the design is good and the preamp has the potential to get better SQ from it. Thank you in advance for your replies. I am interested on learning more about tube amps in general. Take care.

Selling two like new FaitalPRO 6HX150. Planned to use these for some stereo towers but decided to go another direction.

Used in testing for about 1hr, not given high power.

Looking for $150 shipped each or $250 for the pair within CONUS.

Driver specs:
https://faitalpro.com/en/products/Coaxial_Loudspeakers/product_details/index.php?id=351020100

2sj18/2sk60 2 pairs
200usd + shipping 15usd
+PayPal fee or ff option
Or Revolut

With one of my RYTHMIK subs (bought as a kit) when I plug the power cord into the IEC input there is a flash.

Been going on for a few months and decided to take a look yesterday.

These have an input voltage switch and when I took all of the shrink wrap off of the switch it did look suspect.

So I start to map out the wiring and it doesn't look like anything I have ever seen, which is not saying too much. I look on the transformer and it says this transformer has two primaries but one is center-tapped. I have never seen that before which helps explain my confusion.

Easy enough to identify what is what - I feel confident I have it wired with the primaries in parallel but wonder if anyone can explain why this arrangement? Does it have something to do with the dual input voltage? I cannot imagine why this would be needed. Is there a country with 180 volts AC? Assuming center tapped mean it is in the center.

Before I turn it on I would like to know if there is something I am not aware of.

If someone knows the information it will be appreciated.

Thanks and take care,

I decided to simulate the SWTPC Universal Tiger using newer high speed, high beta output devices. Here is an old thread with the schematic: http://www.diyaudio.com/forums/showthread.php?threadid=41926

It does not simulate well with the original output devices, lots of crossover distortion and so on. However, I don't trust the On-Semi models for the old devices. The newer devices make a dramatic improvement. I was only able to do this using Andy C's improved, actually degbugged, models for the output devices, thank you AndyC: http://www.diyaudio.com/forums/showthread.php?s=&threadid=20460&highlight=

I don't know if I'll finish this, but attached is the LT-SPICE model for the improved output stage. I doubled up on output devices so that it will be safe driving 2 ohm loads, and increased the driver bias current. I suggest rail fuses for protection and of course a front end is required. I don't trust the output stage for thermal stability, it should be analyzed. I thought people might be curious to see it in simulation.

Andy's models must be added to the LT-SPICE library, as well as these below. Anyone checked the mje15034 and mje15035? :

.MODEL mje15034 npn IS=3.92866e-12 BF=260.938 NF=1.02215 VAF=15.3399 IKF=0.160087 ISE=1e-08

NE=2.54491 BR=26.0938 NR=1.10885 VAR=153.399 IKR=1.60087 ISC=1e-08 NC=1.89024 RB=0.41209 IRB=0.1

RBM=0.41209 RE=0.0001 RC=0.208002 XTB=0.897431 XTI=1.39234 EG=1.206 CJE=1.61534e-09 VJE=0.698417

MJE=0.382854 TF=1.03079e-09 XTF=1000 VTF=100000 ITF=42.9041 CJC=1.04458e-10 VJC=0.441587 MJC=0.23

XCJC=1 FC=0.8 CJS=0 VJS=0.75 MJS=0.5 TR=1e-07 PTF=0 KF=0 AF=1


.MODEL mje15035 pnp IS=5.81508e-15 BF=313.373 NF=0.85 VAF=40.5017 IKF=0.897023 ISE=6.74258e-16

NE=1.04249 BR=0.958017 NR=0.894461 VAR=148.639 IKR=7.05393 ISC=6.74258e-16 NC=2.84461 RB=3.62039

IRB=0.1 RBM=0.1 RE=0.000923293 RC=0.233799 XTB=2.92628 XTI=1.01325 EG=1.17461 CJE=1.5597e-09 VJE=0.99

MJE=0.554057 TF=1.35882e-09 XTF=1000 VTF=467.207 ITF=58.3338 CJC=1.58888e-10 VJC=0.4 MJC=0.23

XCJC=0.786287 FC=0.8 CJS=0 VJS=0.75 MJS=0.5 TR=1e-07 PTF=0 KF=0 AF=1

Pete B.

from AudioAsylum

https://www.audioasylum.com/cgi/vt.mpl?f=hug&m=153563

I wish I could find a used PAP-C1... If you have one and aren't using it, please let me purchase it! I'm located in upstate NY, and will pay for shipping from anywhere (on Earth).

Thanks!!

Does anyone have a Windows XP install disk they could give or sell me? Or a copy with the password decrypted.

I need a pukka XP machine to run the software I wrote myself in da last Millenium. Yes. I've tried the various Virtual machines but none of them give me the functionality I need. To put this into perspective, I run a DOS window under Win 98 on the XP machine.

Machines that have XP drivers are all more than 10 yrs old. I found one but I lent my pukka XP install disc to a friend who promptly lost it

For sale are four B&C DE250TN-8, brand new. I bought 12 DE250s and 4 that were sent were the TN version and it's too late to exchange them. Looking to get $115 shipped each, or $425 for all four.

Hi,

I'm approaching this starting with an RPi5 & 8-ch DAC (DAC8X), I'll use CamillaDSP.

I want to pickup a stereo set of speaker woofers and tweeters as well as some amplification that will give me good sound so I can experiment with active crossovers. Budget AUD$1000.

I can solder and cut timber.

Thanks.
Richard

Hello all,

Purging some audiophile resistors used in speaker crossovers, all have a 10W power rating. Leads are plenty long for use. All are 50% or more off from retail. All include shipping/Paypal costs and will ship to USA/Canada. I will also take $100 for all the resistors listed below.

UPDATE: ALL RESISTORS SOLD!

Duelund 1R2 [black] - $15 each (2 available)
Duelund 2R2 [brown] - $10 each (2 available)
Duelund 6R0 [brown] - $10 each (2 available)

PathAudio 3.9 ohm - $15 each (2 available)
PathAudio 6 ohm - $15 each (2 available)

Thanks for reading!

Best,
Anand.

I recently could acquire a pair of Quad IIs in need of restoration for a very decent price although without the tubes. I want to share my thoughts on and experiences during the restoration and would of course like to get a few opinions.






Both amps are not very clean - pictures of one of them are attached. One of them (pictured) had at some stage the resistors and the cap on the tag board replaced. It also has an additional fuse for the power tubes. The other one seems pretty much original with all the original resistors and caps.

My goal is to keep the amps as much in an original state as reasonably possible and do not make any irreversible changes, which of course rules out any changes to the chassis and keeping all the original parts even if they are no more used. On the other hand I will do an upgrade to modern safety standards which implies proper use of mains ground amongst other things. I will not use the Quad 22 preamp.

Chassis:I will add a notebook style connector with 3 poles using a 3d printed adapter. The fuse holder will be replaced by a modern one and fitted with a 3d adaptor. A mains switch will be put in the opening of the old mains connector again with a 3d printed adapter and finally a RCA socket in place of the 6 pole connector again, guess what, with a 3d printed adapter.
The chassis must have been spray painted at some point in the past and cleaning it removes the paint anyways, so a repaint is in order.

Tag board: Here I am yet unsure if I should replace it completely with a PCB or try to clean it and just replace the components - it is really very grimy. Any opinions?

Power tube sockets: Yet unsure if I should reuse them or replace them with either screw mounted sockets or also creating a small PCB. Currently I tend to reusing them.

Wiring loom: There may be some risk of broken insulation, but I would take the risk if I keep the tag board. Of course it is also grimy....

Filtering caps: They are no more in really good shape, so I will probably create a PCB for it and a 3d printed holder which fits in place of the old canned caps.


There would. of course also be the option to create a complete new PCB with all the tubes using the original circuit and mount that together with the original power transformer, output transformer and choke onto a new chassis. But even thinking about it amounts to heresy I guess....



Toni

In this series of posts I will give an introduction to SpeakerBench. The presentation is based on a 2-part article Claus Futtrup and I wrote this year for audioXpress magazine. Rather than a general discussion, we focus on a specific application: leakage loss as identified with our proposed advanced transducer model. The advanced model is compared to classical Thiele/Small modeling, with reference to detailed in-box measurements.

Hi all, I'm new here and looking for help with my Rotel RA-611

Hello,
I am selling an AD1862 DAC board to be completed as shown in the photo for 65 euros + shipping.
The components all arrived from Mouser. The chips were purchased from Paddy Garcia on Diyaudio.
I can ship cheaply to many EU countries.
Best regards
Guglielmo

Hallo,

the forum software asks me to introduce myself, but too much talk about privacy probably isn't something I was prepared for when signing up for a forum on technical oriented talk.

Back in the 90's , I bought a pair of diy ACR Axton AX-80 that I still own. Maybe one of the highest value/price products ever made.Of course, it's not high end, it was ever easy to find even more accurate loadspeakers. But it's still getting expensive then, despite the years havin passed.

A funny detail of those speakers is the 50mm soft-dome kalotte that deforms instantly and heavily on touch, but also restores instantly.

Audio Power Amplifier, 2 Channel, ± 2.5V to ± 17V, SOIC, 8 Pins LME49720MAX/NOPB

Same chip as LM4562

Quantity 100

Sealed in cut tape and anti-static bag direct from Farnell


Hi

I don't post much here (long term lurker) but I have been on ebay since 2003 with 100% positive feedback.

These op amps were bought directly from Farnell for the refurbishment of a mixing console but it never happened so I offer them for sale here.

Price through the forum is £150 delivered anywhere in the world, payment by paypal (goods and services - I'll cover the fee). If you would rather you can purchase through ebay: https://www.ebay.co.uk/itm/285980142866

Hopefully someone will get the use out of them.

This GB is Closed.

Amplifier description and discussion -. Q17 - a QUAD405 audiophile approach to perfect sound
This is a full open source project. All documentation, source files, including gerbers, are available at github.
I had no intention to start a group buy, but I get daily mails with people asking to subscribe or to sell to them boards etc.
You may subscribe by adding your name to this google doc.
https://docs.google.com/spreadsheets/d/144EP7ZezFLFgZeNq8q8LCgoa5Lb6z94TKbopFC7S6aw/edit?usp=sharing

Please do not subscribe if you are not sure if you want to participate. Once you put your name on the list, I'll take you in consideration and when target is reached I'll go further with PCB order.
Gold plated PCB is Cu 2oz, 1,4mm thick, FR4, Black. Price per PCB is 27euro and include 2SC2240BL/GR transistors.
Other PCB's are standard Cu 1oz, 1.4mm thick, FR4, black. Price per PCB is 15euro and include 2SC2240BL/GR transistors.
All PCB's for active power supply include 2 Saligny Standard - new version.
For those who prefer a ready mounted module, there will be a very limited batch, at 250euro/module single output stage, or 300euro/module double output stage. Parts are hard to obtain, so do not miss this one.

Shipping to EU is 22euro.
Shipping outside EU is 38euro.
All prices do not include VAT and Paypal fee - for EU. I can ship without VAT if you buy on your firm and is EU VAT registered.

Thank you for your interest in Q17 amplifier. I'm sure you will enjoy at fullest.

Regards,
Tibi

I was discussing my current blues harp preamp design with my dad, and he mentioned that Borbely may have had some concern with FR4 boards...maybe a non-linearity of the material's dielectric constant with varying electric field strengths...something I wouldn't think of as being a huge issue in the audio spectrum, but...I wouldn't know.

I'm wondering if anyone is familiar with his comments on the subject, and maybe could furnish a link to an article somewhere?

Sorry if this is in the wrong place.

Hi everyone. I'm looking for information about bias adjustment.

Anybody ever attempted replacing a socketed op-amp in some audio device with a circuit board plugged into that socket? There are discreet component opamps that are available to do that if that is what you are into, but is it common to say add an active filter circuit into an existing product with this method? I was looking at a Fosi box x5 phono amp that has no subsonic filter but does have socketed opamps for users to fiddle with. Pulling that op amp and plugging in a small PCB with the same op-amp and some filtering caps/resistors around it might be a non intrusive way of modding the original circuit to incorporate added filtering stages to try out.

Hello all,

I have some NOS Airpax double pole mains circuit breakers available for sale

They are high quality, unused, hydraulic-magnetic, fast-acting, 250VAC, 7.5A breakers with an attractive white toggle

• 35mm (1 3/8") cube, push-on 1/4" tabs and requires a 12.5mm (1/2") hole for mounting
• Perfect for medium-sized, transformer input, amplifier projects
• Doesn't require drilling an extra hole and mounting a fuse!
• USD 20 ea plus postage

Data sheet: https://www.sensata.com/sites/defau...04-25/ourproducts_snapak_series_datasheet.pdf

Cheers, Ralph





https://audiofile.net.au

Hello all,

I have a NOS Lambda MB1236 Mains Noise Filters for sale

This is a dual stage Common-mode & Differential-mode noise filter for mains connection

Rated for voltages up to 250V and 36A (!) with screw terminals for input & output

Data sheet: https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/1048/MB_Series.pdf

Ultimate filtering at the point of power entry to a sound studio or within high power equipment

I'm thinking USD 80 plus postage or open to offers

Cheers, Ralph

https://audiofile.net.au/

Hello all,

I have a pair of Hewlett Packard HP 17505A Chart Recorder Amplifier Modules for sale

In very good physical condition but untested. USD 40 plus postage takes 'em both

Cheers, Ralph

Hello all,

Here is a roll of NOS Hewlett Packard HP FSMC-28480 / 9270-1037 Chart Recorder Paper

USD 25 ea plus postage. I have two rolls

Cheers, Ralph

Hi,

I have purchased two REL T5 subs from a guy locally. Don't ask but I was unable to test them since he had no power cables and he was at his work so I just grabbed them. Came home and both dead. No power whatsoever. Changed the fuse, still nothing. I opened the amps and saw both amps same spot with leaked caps and resistors got bad too looks like. Talked to REL and they said "looks like those need to be changed". I have some soldering skills but not for small spots like this.

Can someone help me in South Florida (zip 33326) to fix this or at least direct me to a place with fair prices? I don't want to pay more than $50 (both) to get these fixed. Otherwise, it is not worth it for me.

Here are the photos of the amps.

BTW, the drivers look brand new. Not even a tiny issue on them.

Thanks for the help!