i have some screw terminal capacitors but i cannot tighten them up fully as the threads are probably partly stripped.

any tips for this problem?

After long reading and considerations, I decided it would be good to find out if I was able to build a small Synergy horn using CNC and 3D printing. There are many designs floating around, but most of them just do not fit my idea of size and complexity of build. SPL Runt looks like a good candidate for such a project, so I will use it for inspiraton.

The target is crossover to bass at 135 Hz and 120 dB / 1 m at full power. Or as close to this as practically possible. Crossover via DSP, option for passive would be nice. Speakers to be used - most probably BC 8PE21 and DE500 for the prototype. Most probably, other CD will need to be used (e.g. BMS 4550). Prototype will use 18mm MDF, since that is what I have at hand.

Step 1 - 3D model - is done (well, without some details depending on step 2).
Step 2 - Hornresp model to tune the design. Attached. Not sure, if this is good, bad or usable. To me it seems I can reach my target with a bit of EQ.
Step 3 - prepare CAM files - WIP.

Progress with other steps will follow once I get back home next week.

In optimized conditions for each, which devices generally measures better - thd/gain/output impedance/etc

I have been using a Presonus Temblor T10 subwoofer for the past 3 years. It used to work just fine, until it has been kept idle for about a year now. When I use it now, the Volume knob behind the sub has become so sensitive, that I can't go more than one mm from -30dB.



The woofer gets too loud and distorts. Does the volume pot need to be changed? If so, where do I get some schematic to know the value of the pot?

Hello🙂
Don’t know where to post this issue of mine. This is regarding my bookshelf b&w dm301 speaker. I want to replace all original caps but unfortunately I cannot find the value of one the cap's 11uf 70v . This is for the LF side with .9mh in line. Any recommendations?
Thanks and more power

Hello everyone. I come from Virginia, USA.
So happy to take part in this community.....

Hello all, looking to set up with subwoofer specific hardware for testing and measuring drivers and assembled cabs

I can use REW/ARTA on the software side but what about the hardware side of things. I believe a USB interface is needed. Will have to find a good portable one up to the task

Your opinions and experienced is valued more than google searches. I already purchased a Bheringer calibrated Mic and have a Yamaha MG12XU mixer with USB for non-mobile use. What's considered to be a proper setup in the chain of hardware?

I used to match power tubes in an amplifier by measuring the tube operating temperature. It takes a large lot of tubes, but same tube dissipation equals with operating bias point and tube gain is matched to me. What do you think?

I'm building a BA2018 preamp, and would like to have balanced outputs. There seem to be three options.

1. Build two boards, and make it symmetrical balanced.
2. Use transformers to create the balanced output.
3. Use a balanced line driver.

The cheapest option would be (3). There seem to be boards on EBay for $5 or so, and the parts cost looks minimal. There is the issue of providing 12V (usually). Any thoughts about that? Has anyone here designed a board for this purpose? (It seems like something useful.)

I've actually built two boards, though (as I say in the other thread) am having trouble with one of them, which might have to be ditched, hence am thinking ahead.

Other question. In the BA2018 thread, Wayne remarks (here) that a couple resistor changes (to R18 and R20) are needed for balanced inputs, as well as the big change of connecting -IN through R17. (The original schematic was for single-ended.) But these do not appear on the schematic linked from the store page (here). Are those changes needed or not?

WTB a pair of Acoustic Elegance td10m

just getting into chifi with few questions, hopping to get some answers from the experts here

I was looking at some of the IRS2092S amps and ran across this one with AC input for power on and speaker protection. This seems unnecessary to require 110/220 for amp power on just to prevent speaker power on and off thump.

Has anyone tested these? Maybe someone could explain the benefits of this design.

I am building a self contained DIY Streamer using a Raspberry Pi running Volumio paired with a HiFiBerry DAC2 Pro and would like have it run off a linear powersupply. Now what I'm looking for is a powersupply that:

1. Is a bit more powerful than the Pi USB-C powersupply (27 watts, 5v, 2.5A) so it can drive a:
   • Waveshare 7.9" widescreen HDMI display
   • HiFiBerry Dac2 Pro
   • Solid State Drive (size and make TBD, might re-use one of the ones I have sitting around)
   • Buck step-down converter used for TSOP38238 IR Receiver
2. Can be fit inside a Galaxy 1GX283

The plan is to use panel mounts for any of the Pi connectors I need but have the DAC2 RCA's stick out the back as well as the SD Card. The rest of my parts are as follows:

• On off switch
• Ethernet Extension
• Various ribbon cables
• Micro B Right Angle Plug Down and Micro B Right Angle Plug Up adapters
• HDMI Right Angle R Bendand HDMI Straight Plug adapters
• Micro SD to Micro SD Card Male to Female Flexible Extender

My goal is to be able to powered everything on/off via that switch and have possibly power the DAC and Step-down converter + IR sensor directly connected to the switch rather than through the Pi. I've found that once I connect the Step-Down converter to the DAC's 5v out I start to get low voltage readings on the PI when powering everything with Micro USB.

I'd love suggestions on what kinds of kits there are that might meet my needs. If you have any questions please let me know.

I love sound systems because they enable us to digest great music through our ears into our minds. I used to DIY home rigs (did about 25 in total). I'd love to pick your brains for thoughts, ideas, and harsh criticism when needed.

Hello all, I am new to this form and DIY audio in general although I have long had a passion for audio. I currently own a pair of revel M106 and my father owns some Salon 2s. I am interested in making the "Best" Horn loaded "party" speaker. I am a big fan of music festivals and want to recreate that chest thumping bass and levels where I need to put my musicians earplugs in but as high fidelity as possible. I have been taking some inspiration from the likes such as funktion-one, hennessey sound https://www.hennesseysounddesign.com/point-source/ , and KV2 VHD2 https://www.kv2audio.com/products/vhd-series/vhd20.html . This sound system will eventually be placed in a "great room" likely a flown array to get even front to back coverage. I am currently thinking of 4" 1.4" exit beryllium compression tweeter such as https://radianaudio.com/collections...s/951-4-diaphragm-1-4-exit-compression-driver and possibly paired with one of these horns https://www.parts-express.com/B-C-M...ctivity-Horn-70x55-4-Bolt-294-6184?quantity=1 . Hennessey makes mid bass and subwoofer boxes that do 75-300 and 25-100hz respectively that I would like to emulate or possibly just purchase.

My biggest question still is how to complete the midrange likely 275/300-1???hz I want to have as high fidelity as possible but it also needs to be comfortable at 120 and reach up into that 130+db peak levels.
maybe https://www.madisoundspeakerstore.c...nx-003-e0073-08-6-graphene-cone-woofer-8-ohm/
or Purifi Ushindi 6.5" PTT6.5M08-NAA-08

I plan to do this all on active dsp crossovers with 7 separate amplifiers to get the timing, crossovers, and frequency response perfect.

Any and all advise is welcome!

Carbon fiber, solid aluminum outlet plate with mounted R1 outlet. New, never installed
$200 plus shipping.
Thanks for looking.

I have a milling machine.
Max speed around 2000rpm.
I'd like to mill slots for component lugs in FR4 PCBs or stripboard.
Has anyone done this and can advise cutters & techniques to avoid the cutter jamming or breaking?

I have a Marantz CD-74 on the bench. Initially, it would NOT read any CD. The platter would not turn at all. I tweaked the height adjustment screw and laser power pot just enough to get it to read a CD. Then, I worked through the adjustment section of the SM. There are only 4 adjustments called for -- Laser Output; Turntable Height; Radial DC-offset, and PLL Circuit adjustment. I do not have the Philips test CD, so I performed these adjustments over a handful of commercially pressed CDs, and the adjustments are all well within specs.

Now, the unit will play most CDs but not all. When it plays, the RF eye pattern looks reasonably good. It's about 1.2v PP, the eye is sharper on some CDs compared to others. Even on the ones it plays well, it takes a moment to start up. If you watch the eye pattern on start up, you can see that the machine takes two or three trys before it locks in and plays. I only tested with commercially pressed CDs.

I should mention that the CDs that it will not play, are fine on other players I have.

There are NO philips blue radial caps in the unit. The caps are all Elnas and test good in circuit with a Peak ESR meter. The power supply voltages are spot on.

Because of the effort at startup, I am starting to suspect that the Focus Offset or Focus Error Adjustment may need to be adjusted. These adjustments are not covered in the SM.

Does anyone know the adjustment procedure for these two pots on a CD-74 or CD-84? Since I finally have it playing some disks, I am very hesitant to change the settings of either of these without more information.

Alternatively, is there something else I should be considering given the above?

I have a problem with several of these modules for my BGW amplifiers. One module has this problem where -when I plug it in it will work fine for 20 or 30 seconds, then it will make a big "pop" noise and the music will come out distorted. Or, when I turn on the amp, it will make a (snap, crackel, pop) noise, and the music will come out distorted, then it will make another distinct pop noise, and the music will come back out clean again for another minute or two... and then it will make that pop noise again, and the music will come out distorted. Djk, do you have any ideas? It sounds like a cap or something on the module, but I don't know where. Also, I have three other of these modules that are toast. When I turn on the amp with these modules, it imediately cuts off and goes into protection. I have been trying to get some replacement transistors for the modules as well. Djk, I read a previous post to a question you answered about another guy who was trying to replace them too. I know that you said to use MJ15024 for earlier, and MJ15024/25 for later, but I cannot find these anywhere. Some of my modules have Motorola (SJ 7394 7852), or (SJ 7394A 7952/ 7939) or (SJ 7407A 7926) or (RCA 6803407, C, 7913). In the service manual it says to use SJ 7394 (part #1854-7394) for the upper rail of the module, and SJ 7407 (part #1853-7407) for the lower. Does anybody know where I can get some replacements comparable to these at a reasonable cost. Also, does anybody have any additional tips, tricks, comments, or suggestions for testing procedure of the transistiors, -or general maintenance of the modules. I am an amateur and NOT an experienced pro, so I would really appreciate any additional input. Thanks

Hi, interested in hi-fi from 70's. 80's and 90's and all types of music. Just getting back into vinyl after restoring a Garrard SP25 mk2 deck. Currently working on an HMV radiogram for a friend.

Anyone who's working on any unit and using any pmc marked chinese transistors, here is some die measurements. It's a 2SC3519
I accidentally killed this one with arround only 20volt dc
Looking like 3.5mm die size i dont know if its good or not.
I used some pliers to open up this transistor.
Edit1: I use this transistor in my amplifier (Pioneer sa7800) it holds up with a TO220 70-90watt transistor. I plan to replace it with something genuine.

Hello all.
I have an RF 400.4 on the bench, all powers up fine and stable current draw. No overheating.

The problem is with the front channel, it's picking up noise from the cd source unit, you can hear the cd tracking when loading and skipping the disc.

The reach channel has clean audio and doesn't pick up any interference.

I've tried switching the rca's, earthing the rca shields to the head unit, using the same earth for head unit and amp. I've also repaired loose rca input solder joints and cleaned crossover and gain pots so far.

When I turn the front gain down the noise reduces but when it's turned up its very apparent.

All 4 rail caps are bulging.

Any help appreciated, thank you

I just created a small universal add-on to measure capacitors with my DMM. It’s based on a thermo-sensor that I received with some of my DMM’s. I just used the connector and cut the wires.

Just hold the capacitor you want to test on the small pcb traces and voila, you have your capacitance reading.

Regards, Gerrit

Back in 1968 the typical drivers for 2N3055's were the 40361 and 40362. I suspect these were Quad's 38495/6 (although shipped with a heatsink flange). They might have been the 40634/40635, which seem to be uprated 40361/2.
The BD139 and BD140 can be used as replacements but would need some refitting to accommodate.

Candidates for TO-18 devices back then rated at ~65V+ were not common. The BC107 types could only manage 45V. Perhaps a selected BC107 for 65V? The BC477 was rated at 80V but I think it was introduced later. Replacements could be 2N5401/2N5551 though some have suggested BC546/BC556 but at 65V that is marginal. The MPSA06/MPSA56 are obsolete, as are the ZTX304/504 which were suggested as options too.
Does anyone know what the U17219/U17229 devices were based on?

Hello all.
I have an RF 400.4 on the bench, all powers up fine and stable current draw. No overheating.

The problem is with the front channel, it's picking up noise from the cd source unit, you can hear the cd tracking when loading and skipping the disc.

The reach channel has clean audio and doesn't pick up any interference.

I've tried switching the rca's, earthing the rca shields to the head unit, using the same earth for head unit and amp. I've also repaired loose rca input solder joints and cleaned crossover and gain pots so far.

When I turn the front gain down the noise reduces but when it's turned up its very apparent.

All 4 rail caps are bulging.

Any help appreciated, thank you.

Hi,

I have a pair of Diatone P610MB single-driver speakers (40 years anniversary) in wooden cabinets and I would like to add a super tweeter. I would appreciate your advice in-terms of what to chose (as I'm not an expert), a few questions:

• Any specific models that you would suggest?
• is super tweeter or compression driver preferred?
• shall I chose an Alnico tweeter (given that the Diatone drivers are Alnico)
• do I need to add an attenuator as well?

thank you in-advance for your advice!

Hello
I'm music lover and audiophile lover till i am 15, it was in 1990.
I'm deeply interested in this forum about renovating vintage material.
And i now want to build my own triode amplfier

all the best

I'm looking for a simple ADAT to 8-channel analog out. Doesn't need to be fancy, 44.1/16 is enough.

I'd prefer it to be a pcb as it is to integrate with some other boards. Something like a ADAT to 4x stereo SPDIF is also an option as spdif da converters are easier to find. Or as a last resort a reliable source for the Wavefront AL1402. I don't fancy making aboard for such an application but if that is the only way...

Got this Linn all working fine , digital outs also working fine
Nothing comes out from analog outs Both XLR and Rca
any ideas

While I am not new to DIY audio equipment, I am newer to this forum (I've been a member for just over 3 months). In these last three months I have already accumulated quite the pile of shame. I have pretty much been a part of every single group buy since I joined and picked up other projects along the way. With a backlog of projects I found my self continuing to purchase new projects to do “down the line” versus completing the ones I already have. So, I have created this thread to hopefully stay focused, I blame the ADHD, and build what I will consider the central point of my audio system(s).

Nothing I have planned is set in stone and would love feed back from the community. There are Probably some oversights that I have yet to encounter.

• Support multiple projects by other forum members
• Learn a bunch of stuff along the way
• Unintentionally be overly complicated? Probably.
• An Internal DAC on Input 1
• DAC with USB, optical, and possibly other inputs
• With the DAC on IN1 I want at least 3 additional Inputs
• Inputs 2-4 must support XLR and RCA
• Some sort of front panel display even if it's simple
• Front panel power switch
• Headphone Jack
• A well-designed front panel with simple controls
• With the final goal of having fun with it. That is the point after all?

The Preamp controls I have decided to go with John's Preamp Control boards. I have the boards and parts in hand to assemble and test. I like the layout and the functions of the front panel display and controls. Including the feature of being able to use a remote control.

The preamp section I think I am going to go with the Omicron. Due to its size, affordability, performance, and the ability to act as an HPA and a preamp. I think this fits the bill nicely. I have these almost fully assembled, I am missing a transformer and some random bits that I missed on my Mouser order.

The DAC portion of this project I have decided to go with a project from @abraxalito. After much Success and enjoyment from my competition of his Abbado II project, I'd like to implement more of his work into this build. I also will more than likely be getting another I2S input board/selector that I used in my Abbado II build.

I have begun to start on a front and rear panel design in FPD. Its nothing to special as I'm still relatively new to this program. I have decided to go with the Modushop 2U Pesante 02P400B. The internal dimensions of 400mm x 430mm x 80mm should be plenty to fit everything I need inside.


The Omicron uses SE inputs on the board, which works if I'm using SE inputs but what if I am using balanced?
I thought of using the Universal Buffer from Neurochrome, but I have to set up a switch to change from either SE to balanced on top of needing a buffer before and after the omicron. I don't think this is that great of a option, but I am open to ideas.



Attached below is a capture of my front and rear panel ideas and the preamp control boards plus omicron and its PSU. The front panels and rear panels are done for all the options I have decided on (This will change if I go a different route with anything)

Rear panel has the first input removed since the DAC will be internally wired to it, Then the three other inputs the Outputs, the I2S input selection for the DAC, IEC connector.
Front Panel has the preamp controls, volume, input, selection, display, and LED for showing which input is selected. There is then a mirrored side with the input selection for I2S. Crossfeed switch for the Omicron, Power switch, and the headphone jack.

Thanks for reading! I'll post updates as they occur. If anyone has any ideas for this project please post them! I am open to them!

Got the Chinese board with this chip on it. Meters work OK with normal program material but with little or no signal, the pointers
"bounce around" their rest position, like noise is getting in. Suggestions?

THANKS

$25 plus postage.
Thanks for looking.

M

Greetings,

I would like to share an idea of an audio amplifier that I wanted to develop for my home speakers.
The target is to build a 200W Circlotron with the following guidelines:

- Zero global feedback
- Same N polarity output devices: for a wider range of output devices including IGBT.
- PnP auto bias: no need to adjust bias even when swapping output devices between BJT, MOSFET (Enhanced) and IGBT.
- No thermal tracking.
- Output devices never switch off: no switching crossover distortion with low idle current and no transconductance doubling.
- Symmetric and flat output impedance.
- Modular: swappable voltage stage, driver stage and power stage boards.

This is the start, with the follower power stage section as in the picture.

It will follow the gain stage with different solutions:

- DC coupling: more challenging and it may require DC servo.
- Capacitor coupling.
- Interstage transformer coupling with tubes.


I wish that people interested in this project will enjoy all contributions and have a complete ownership of the results in the DIY community.

As it was done under the top cover of the Commodore Amiga 1000, I wish to print names or signatures on the future PCB boards.

Thanks to Kendall and Cordell

Alfonso Pelizzo

I have generally found that the ripple pool simulator in Hornresp works surprisingly well, to figure out the radiation patterns of:

Dipoles

Bipoles

end fire and gradient arrays

It probably seems counter intuitive that software that was based on nothing but "dropping stones in a pool" can work so well, but I've had good results. If you guys remember my thread about the Bang and Olufsen Acoustic Lens, a lot of the early sims were done with nothing but the ripple pool simulator.

The problem is that the GUI is unbearable.

Having to click on individual pixels like it's 1985 and I'm making sprites on a Commodore 64? There's gotta be a better way.[/b]

Does anyone know?

• • I know that Vituixcad can simulate the response. Something that's tricky with Vituixcad is that you can't watch the wave propagation. And being able to do that is really helpful. For instance, the Hornresp ripple pool simulator clued me in to the fact that the sharp edge on the B&O lens is a problem. (They never fixed it, so they may not even know!)
  • ABEC can obviously do it, but making loudspeaker meshes with ABEC is about as much fun as going to the dentist

Someone on Facebook made a post about a piece of software called "Treble Audio Suite" which looks like it can do it, but it's $1500 for a license, per year. Way too much for me.

Edit:



Looks like Mabat had the same idea (see above.) But I don't think it ever made it into any of the releases. And, also, the ability to introduce delay and create arrays is really what I'm looking for. I want to simulate gradient arrays in particular.

A bit unsettling, hotel prices in Paris have fallen by as much as 50% England's star equestrian kicked off the team for whipping her horse. Japan's Shoko Miyata demoted for smoking a cigarette (how Un-French is that!). Delta Airlines expects to lose $100mm as flyers avoid Paris.

I am trying to find modern equivalents for HZ6A1L and HZ162L zener diodes and I would appreciate it if someone could help me find suitable replacements.

According to the datasheet I found, the HZ6A1L has values of VZmin = 5.2V and VZmax = 5.5V. The closest ones I found for that one are BZX55C5V1 and BZX55C5V6 zeners. Which one would be a better fit?

The HZ162L has values between 15.7V and 16.5V. The closest one I found for that one is BZX55C16.

I'd also appreciate it if someone could explain the ranges in voltage ranges in zener diodes and how they impact the choosing of equivalents.

Hi everyone,
I was messing around a bit on my Cambridge 851N Streamer/DAC and thought of swapping the final opamps (BB OPA2134 SMD) with discrete ones.
After removing the 2 original opamps and soldering the new ones I noticed random noise mixed with the audio on one channel (right channel). I though that maybe the new opamps were oscilation or just not good for the purpose, etc, and dessoldered them and placed the old ones again.
Now, random noise on both channels, higher on right channel. This is on both RCA and XLR oupput as the opamps feeds both.
So, again, these are smd's and soldering and dessoldering these can be tricky and I think I may have applied heat for longer than I should.

The +15V and -15V for the opamps are OK. The traces are also good. I measured the audio ouyput and I read negative DC voltage on both channels. the voltage goes up and down. Is around -2v on the left channel but on the right channel goes up to -15v sometimes.
I asking for some help on which component can maybe be damaged due to overheathing. Maybe the small 47p capacitors aroud the -15V rail close to the opamp?
I'm adding some files. Also have the full schematic.

Any help would be greatly apreciated!
Againg, everything works well, except for the noise caused by the negative DC.

Thanks
Andre

When building a variable power supply, where is the ideal place to put the variac? before or after the power transformer?
Thanks in advance.

So whenever i connect the NFB cable to the secondary there is this loud hum that even at the max volume i can hardly hear the music and when i disconnect the audio input it just gets increadibly worse tubes literally start to scream but when NFB is not connected i get proper sound and i dont know why but sometimes when i connect the NFB it just works and i get great sound
what might be the reason of this

Thanks

Here is the amp schematic

Hello,
I'm looking for some help finding some Shuguang EL156 tubes. Apparently they are not made anymore and are hard to find. Any help would be greatly appreciated.

Thank you.

I have two Thor subs, each with its analogue crossover. With peerless xls 12" drivers. At present crossover set at 50hz I think. I am not guaranteeing the crossover is working, but they were working when made up.

I've never used these, and so they need to go to someone who will.

Each individual subwoofer with its crossover £150.

Collection from Guildford Surrey. No posting for obvious reasons... 🙂



Thanks.

As mentioned earlier, we intend to perform our own distortion measurements on a collection of IV converters we have on hand, for our own education.
https://www.diyaudio.com/community/...st-tht-i2s-input-nos-r-2r.354078/post-7594471

Here are the measurement results.
All thanks are due to Fran for all the measurements.


Patrick

.

Hello All!

I built a small rig to play in a small outdoor area, but Im having a lil trouble with my QSC amplifier clipping out on the subwoofers, and it seems like Im not getting all of the wattage out of the this amp. Everything I bought used from FB, because I cant afford new. I play mostly House, R&B, and Disco. Heres the setup:

• QSC MX-1500a - used and rebuilt amp by QSC pro, connected to subs with banana plugs, bridged.
• Two homemade bass cabinets with one 18" Soundtown 8ohm sub each, around 450watts RMS, my closest guess is STLF-1804-8. 25 x 25 x 30.
• Two JBL G-734 15" tops
• Crown XLS-402 amp for the JBLs
• Rane EQ (Its flat except for lowered midrange)
• DBX 1066 compressor
• DBX 223XL crossover used in 2 way, crossover at around 120hz
• Mixer is Rane Seventy two
• BBE maximizer is on its way to help sweeten the sound.

Connections:
Mixer->EQ->Compressor->Crossover-> Each Amp.
Im aware I should put the EQ after the compressor, which might help quell some of the midrange, I still have to try that, but thats another story.

Subs are wired in parallel, I think its possible that the amp doesnt have enough wattage for these subs. It should but it doesnt act like it whether I use it bridged or stereo.
Amp sounds fine, but even after severely compressing/limiting the signal to even out bass peaks, I still get a clipping amp and popping out of one sub, and the output doesnt seem to be 1000 watts, and im testing in my house. (RIP my ears). The bass doesnt seem to have as much pressure as other systems Ive seen. BTW I did reverse polarity on one of the sub to make sure they werent out of phase, theyre not. I did alot of tuning with the compressor settings to get to this point. If I dont use the compressor, of course the amp clips much quicker.

So I said ok, Ill buy a Crown CE-2000. It should be 1950 watts bridged at 4 ohms, this should work right? Nope, its clipping out too at near max volume. I think this amp is one of their lower quality amps.
So now Im thinking I dont have nearly enough real power to drive these subs.

Does anyone have any suggestions as to if Im setting something up wrong, or which old heavy duty quality amp I should buy used to drive these subs?
Im having a hard time being able to figure out the quality used amps from the cheap ones on my own.

Right now, Im looking at pics of the interior of the amplifiers to see which ones are actually heavy duty vs the cheap ones. But Im not an electrician so its ignorant guessing. I know how to tell with Car Audio amps, but not with PA Amps.
I see huge transformers in pics of a Macro-Tech 2400 or Crest Audio CA9 that the MX-1500a or CE-2000 dont have.
I was also looking at a QSC PLX-3400 but Im not sure thats up to snuff either, but I can find it easily online.

What say you guys?

A friend has the following compression driver in his 3 way system and one of them has gone bad. Does anyone know of a source for a used or NOS of this driver? Thanks.

https://audio-database.com/YAMAHA/unit/ja-6681.html

or

https://josephcrowe.com/blogs/news/yamaha-ja6681b-compression-driver

Finding a vintage compression driver today is like discovering a historic car in a farmer's barn.
Here I'm talking about the driver Yamaha JA6681B. This driver was also sold (after some tweaks to prep it for PA applications) by Meyer Sound. The driver got the name MS-1401A.
So MS used the driver in some PA speakers and also in studio monitors, e.g. 833, https://device.report/m/e1d3ec4c25873f9add652e1187081958d6d4211c3def248664dc783ffc0264e0.pdf

Hypex Fusion 3 channel plate amplifiers, FA253, (250W + 250W + 100W),

These are older version so can't do FIR filters

Selling as changing to multi-channel DAC setup and can't use them.

Price SOLD

Power (4Ω):2 x 250W + 1 x 100W
Power (8Ω):2 x 150W + 1 x 100W
Can also bridge the 2 x 250w to create a 1 x 500w amplifier.
Channels:1 channel / 3 way
Technology:NCORE®
Family:Fusion Amp Family
Mains voltage input:100-120Vac / 200-240Vac ±10%



Connections:
Analogue balanced XLR in and through
Analogue unbalanced RCA input
Digital AES in and through
Digital S/PDIF in and through
Digital Optical TosLink input
USB 2.0 configuration interface

I remember a short project/article in an old ETI magazine (perhaps 1986?), the premise was to recreate a valve sound using transistors (5x MPSA42?). From memory the preamp had a two small transformers back-to-back and a rectifier to create an HV rail and a gyrator config using at least one transistor for the PSU. It was at least two stages and had an RIAA network slung between them, feedback was provided by emitter resistors?

I think the ETI copy had something white on the front (like a synth). Could also be wrong on the year (85-87).

Don't suppose anyone remembers the article or has a stash of old ETI's?

Recently retired, now I have the time to recreate those wonderfull memorys of my teenage years when I first discovered the amazing sound that a pair of Altec A7 Voice of the Theaters delivered. Starting a referb job on an old pair I found and hope to pick the brains of all great minds on this site...thanks

Would like to buy a Hans Polak MC phono published in Linear Audio

/Anders

Hello,

once again an annoying problem... I have a Sony CDP-X229ES that has the problem that after start playing the music the spindlemotor slows down, stops and then nothing works on the player. The functions only work again after the device is switched off and on again. However, reading the CD works perfectly, and start playing the CD works immediately, but then......
I have already cleaned the drive, replaced both motors (spindle and laser unit) and last but not least changed the laser unit. Supply voltages are all present and in value.
To my chagrin, I have to admit that repairing CD players is not one of my top activities. Does anyone have an idea where I can continue, or does anyone even know the error?
Thanks in advance for your effort

SOLD

Thinning out the number of amps I have. I built each of the amps for sale for personal use and am selling for below cost of construction.

Basic details: Deluxe 4U chassis. ThatcherDIYAudio boards, Antek AN-4218 transformer, PRP metal film resistors, Mills power resistors, CDE 380LX 33,000uF 50V PS capacitors, Cardas and Kimber wiring, EAR Isolation feet. Functions perfectly. Will be carefully packaged for shipping.

$775 incls. shipping within Continental US. Payment via Paypal.

Just wondering how much something like this is worth? It's about 18cm across and 7cm tall and nice and heavy!
Here's some pics:



(matchbox for scale)

Hello everyone. Nice to be here. Hope I’ll manage to do interesting audio projects to share with you👍

For sale in verry good condition and top working drivers from Eton Germany.The Kit-8.2 is a 3 way loudspeaker with top Eton Hex bass and mid driver and silk dome tweeter.This is a steteo kit.I also have crossovers build on the original plan with top parts,but this add and price is only for the 6 units.If someone interested plese contact me.Look on the pictures for condition and data.Shipping within EU is free,outside plese ask for shipping costs.

Hello diyAudio members , i've registered a couple of years ago and been reading along here but never really posted anything. Now that i'm finally having a bit of a diy audio project i'd like to discuss some things here with people that are a bit more experienced in the audio field. I've done electrical engineering so i'm a bit familiar with general (micro) electronics, but audio is a whole thing on it's own. Have a good day and enjoy your music!

Hi everybody,
I'm trying to make a mono, phantom powered version of Elektrosluch with a balanced out. Elektrosluch is an open source design created by Jonas Gruska of LOM Audio, basically it's a stereo EMF detector with an OP amp preamplifier (schematics here).
The core of my idea is to use an OP amp chip like NE5532 and build a single-ended input to a differential output amplifier powered through the +48 phantom power provided by my recorder. I came up to this design, can I have a comment on that?

Hello

I have a rockford fosgate punch p1000-1bd hooked up to a Power HX2 15" (RFR3115) subwoofer wired up to 1 ohm. I had it in the car for some time, but it was never playing how i would like it to. The amp is rated 1000W RMS at 1 ohm but it dosen't fell like 1000W, the sub bearly moves. Also i noticed that if i turn gain higher the amp start clipping so i have gain set to 4 out of 11 is this normal? I measured with an osciloscope that my headunit signal is not clipping and it's not, also checked the amps pdf and it says RCAs can go up to 5V but i only have 2V. The amp also hes something called Punch EQ whitch i have at 0 because if i turn that up the clipping just becomes worse, the amp dosen't have a clipping light but i measured the signal with an osciloscope and saw it was clipping alot. Also when i turn gain up and the amp starts clipping it starts to make some weird noise, I alreday opened the amp and checked the resistor that some people said it breaks, also took out the main capacitors and measured them and then were good. I was testing it on a bench with a stable 13.8V, the plus minus voltages inside are around +30V and -30V. I have a fealing that the problem might not be in the amp but in the preamp. Amp still works but it just dosen't feel like it is putting out the power it should. Or is this just normal for that amplifier? Could it be that my box is not good? i do have a 70L ported box but in the subs pdf it is suggested 100L box.

Any help would be greatly appreciated.

Hello, I'm a diy tube amps enthusiast. I've had this account for a while and I've been usually able to find all the answers I need without posting. Now I need to message other user. Thanks!

New, just mounted, with the crazy Hope they would have sung with 3.5w set. They play but Need more juice to work. Sell with purchasing invoice dated few days ago. In the picture you see they still have the post-production powder coating on their suspension. Ask for 700 Eur plus shipping costs.

A friend of mine (Bogdan Rosca) did this recently and asked me to upload some information about his construction as he's not so used (yet) with forum activity.
The input, interstage and output xfmrs are made by me, so you know who to put the blame on 🙂
The test is made with a Lowther full range and a mike Umik 1, otherwise on a resistive load the response is pretty linear even if the signal is processed through 3 audio xfmrs per channel 🙂

**Cancelled on 31 July due to lack of interests.

I intend to order AD1865N-J dac chips from Digikey. They are supplied by Rochester Electronics. They are probably the last place on earth to stock brand new, genuine AD1865N-J chips (No N-K grade chips available).
Some project proposals here :
https://www.diyaudio.com/community/...2s-input-nos-r-2r.354078/page-72#post-6525201
https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-439#post-7738612

I did the calculations ie. shipping cost to me, import tax + DHL tax handling, shipping materials to you, etc etc. + a Starbucks coffee from you
48USD (covers shipping registered + tracking to you) sounds about right.
I need at a minimum of 5 more pieces to proceed. I will eat the rest of the chips.

I will leave this open for a couple days here to see how things go.

Anyone affected by the above? They probably asked some junior coder to do a quick patch and the whole planet goes down.

A genuine ‘Oh ****’ moment.

What can you do but shrug your shoulders?

Just looking in the Guardian at the airports that are down: La Guardia, Singapore, Hong Kong, Toronto, Gatwick, Milwaukee - the list is huge.

Testing a pair of these shows sensitivity seeming to fall short, about 87 dB / 2.8 volts / 1 metre. (the actual sound level measured at 2V is about 84 dB, so extrapolated). Pulling off the deflection pads completely brings the output up another 3ish dB to roughly 90 dB until about 9-10 kHz, where it rises to about 93 dB. I know my numbers are close to correct since a Bliesma T25B on an Augerpro 6.5" waveguide comes in at 98ish dB, as expected.

The Raal spec sheet claims about 4-5 dB more than I measured for the 70-10D, so what am I missing here? Both tweeters show the same numbers and the response curves match well so it shouldn't be a case of a bad unit.

G'day Guys,

I am working on a PCB design to fit in place of a Broskie 12VAC Aikido PCB.
Long story short, I have run out of tubes for the 12VAC Aikido so it is time to pass that sought after board onto somebody else.

It's also a good excuse to use a FE2022 essentials kit I impulse bought from the store a while back.

The catch is that I spent 6 months making a chassis around the Aikido. I spent too much time cutting, folding, drilling, sanding and painting not to reuse the chassis.


The new pcb has to go here:

The goal is to get everything onto one board so that I can simply replace the donut and PCB and button everything back up for immediate use.
Hopefully no drilling into my lovely paint work. Definitely no cutting!
That means a PCB of the same dimensions as the 12VAC Aikido or at least the same hole centers.

I am working off of the V0R1 schematic:

I have removed R14 as it isn't needed.
I have removed the trimpot P1 as I am not worried about DC offset.
I have removed R11/R12 as I am using a bipolar supply.
I have removed R9/R10 as I think these are an RC filter for an external DC brick and I will be using a regulated linear supply.
I have kept C6, just in case.
I have decreased C4/C5 to 100uF which seems sensible to me as decoupling for a regulated PSU.

Thus I have come up with this:

The PSU will be a VRDN. I was going to shoot for +/-24Vdc rails but I don't have any appropriate donuts, so I will run +/-20Vdc rails.
I have applied the changes Mark Johnson recommends for immunity to manufacturer variations in the LM317/337.

And here is the first draft of one channel of the FE2022 part of the circuit.

Shown with the output caps of the VRDN on the left.
I am happy with the parts placement.
The grounding is subject to change as I layout the PSU but I intend to keep the signal ground separate from the PSU ground except for the single point of connection.

I am going to see if I can fit separate regulators for each channel driven from the combined cap bank.
a) LM317/337 and denoiser parts are cheap.
b) This should allow me to get the regulator outputs closer to the FE2022.

I am wondering if with the output of the regulator so close to the FE2022, whether decoupling is necessary at all?

I have seen suitcase boomboxes, ammo can boomboxes, cardboard boomboxes, PVC pipe boomboxes, and Pelican case boomboxes. How about a dinning room table boombox build?

The $30 CraigsList dinning room table:





Strip off the extra pieces:



Trim off the rounded over edges:




The other end:


This is roughly what I am thinking of for the subwoofer layout. The 6" subwoofer facing forwards and the two 7" passive radiators facing backwards:

I believe the lines in the table are groves that they cut into the bottom to keep the table from warping. Since they are on the inside I can fill them in with epoxy for strength if I need to.

The plan is to have the sub in the left half of the box and the electronics in the right half of the box. The actual speakers are some bookshelf speakers I REALLY like. Rather than trying to build my own imperfectly tuned speakers I am going to go with professionally built speakers and just do the sub/electronics box then hang the speakers on the sides so they are removable.

So now I have a rough cut front and rear:



The pieces are 3/4" thick supposedly maple. If it is maple it is a soft maple. I usually work in hard maple. I think it is another wood... Alder? Beech?



They look they are going to make the boombox pretty tall. Some alternate driver and passive layouts:


The board is a piece of Ipe I plan on using to enclose the box. It will pretty much set the depth of the box:


Maybe I will rearrange the drivers a bit:

Wise people of the forum, greeting from the bottom of the planet.

I'm looking for recommendations on the best shielded signal cable to use in a tube preamp and tube amp that I'm building, together with a supplier I can source from. Cable for anywhere in the US or Europe is OK. Here, in NZ, there isn't a lot to choose from, and what there is to choose from is little better than a wet piece of string.
Ideally, the cable that is sonically and electrically ahead of the pack is what I'm looking for and also something easy to work with and that holds its shape once put into position.

Looking forward to hearing from those more experienced than myself.

Thanks!

A set of concept subwoofer cabs to trail a few drivers and choose a system for my mini DJ rig which I am calling the VolcanoSS or Volcano Sound System

It should be noted that the low volume cab sizes as drawn are designed for Low Vas/high Xmax drivers/very high power type of drivers such as the DS18 ZXI12.4d and ZR12.4D. The cab concepts will explore if drivers that can usually be heard from a street away can be ported to domestic and live use. This cab volume is easily increased for use with regular drivers

Build is using any stiff machinable material or combination off. Walls are designed to use 'thickness for stiffness' and at minimum MDF for pro or XPS for domestic duty and PVC foam for super heavy duty. MDF can be painted or veneered, but best performance and durability results are with an FRP sandwich. This will remove any remaining flex in the MDF appropriate to super sub duty

Driver location keeps the roll surrounds out of the main air volume, and the air cupped by the cone will add to the main air volume. A FreeCAD macro is used to determine the exact box material volume and then cavities are created, and the macro shows the new material volume. The difference of the two is the chamber air volume. The model takes the air volume within the driver cutout area and loss due to braces into account using this process

A small desktop CNC is required to build up the former in areas thicker than the panels and the tricky bits, but the cab can also be done using kerfing and knowing use of hand tools

The design can be reproduced in any manner or for any purpose. There is no IP concerns but keeping the VolcanoSS name is desired. This is just a design concept and can change


Volcano TLS
First up is the Volcano TLS, a sealed design concept targeting heat management. The driver is fitted reversed so that the motor assembly is in free air. It can be configured for any driver size, and cab volume is adjusted by changing the height of the upper and lower secondary air volumes. Both secondary volumes aren't required to be used at the same time or at all

The upper and lower chambers can also be closed off to use as an electronics bay. Or another chamber slice can be added to the cab for such use. A cavity or pod attachment can be done to the rear panel for terminals or electronics

The large blank face can take a fabric print sock or Plexiglass window. Mesh from a very large strainer can be modified to fit over the back of the driver. A rim for the mesh can be machined or printed. Alternatively, a fabric sock can be fitted over the whole speaker and recommended easy method

A second unit can be built on the other side of the face for a dual opposed setup

As drawn, the model is for a DS18 ZXI12.4D vs DS18 ZR12.4D trials, but the model can be adjusted to any driver and internal volume
Model specs (variable)
Internal air volume 19L
Width 360mm, height 540mm, depth 332mm
Wall thickness 32mm




Volcano Kiss
Another sealed design concept with heat management for a conventionally mounted driver. The long side panels are 3mm alloy plate to couple internal air to the room for heat dissipation. An alloy heat collector shrouds the magnet and couples to the internal 3mm alloy plate rib. This plate is spaced out from the back panel using battens

The back of the magnet also couples to this plate for heat transfer as well. The plate has a hole that the pole vent fires through and, with the battens acting as standoffs, couples back into the cab air volume. A lock can be added to the top surface of the shroud to secure the magnet if desired

This alloy rib runs across the cab and couples with the alloy side walls. Why alloy side walls?

This is a fairly flat cab, two can be brought together for dual opposed. The back is deliberately kept clean to allow this

As drawn, the model is specifically tailored for a DS18 ZXI12.4D, but the model can be adjusted to any driver and internal volume. Volume is changed by changing height

The third pic is only the alloy structure. Let's call it a 'TF radiator'. Last pic shows dual opposed

Model specs (variable)
Internal air volume 24L (driver is 4L)
Width 360mm, height 450mm, depth 248mm
Brown = wood, red = internal wood, grey = alloy




Volcano TLAmp1 and TLAmp2
Will be building this one to break the driver in and test the small Sd proof of concept thingy for the pro mobile subs. This folds such to fit in the car but also, if it works well, will form the basis for the potent instrument amp. Preferred over the BR due to managing the pipe resonances better, tuning the pipes in HR as a TL. Full story here
https://www.diyaudio.com/community/...fer-cabs-design-and-build.415232/post-7745529

Bretheren -
How long do woofers last ? Please hive, weigh in on the prospects of building one last system from old stuff or giving it a local makerspace which does a lot with high school kids, maybe one of them will get the bug to build audio. The speakers I'm thinking about below go into a music practice room and will be used for playback of amateur recordings with my groups and YT and other recordings of very assorted music and widely varying quality for practice and rehearsal. No engineered listening space with carefully chosen source material and recordings.

It's been thirty years since I built the last project , a pair of Dynaudio 15W75 + Focal tweeters which has served nicely in our kitchen since. Previously during batchelordom in the late eighties , It was a pair of 17W75 6.5" drivers + Dynaudio tweeters,The 17W75 have sat for the last 25 years, replaced by a pair of Quested 10" nearfield monitors , now also gone.
The kitchen speakers are about to be retired in a remodeling , and I'm wondering if all three drivers would make a worthwhile bi-amped 3 way. A pair of ICEpower stereo amps + a line level crossover to drive them. So cost of this system with pretty good amps ~$500 with cabinet material. I'll note that the 17w75 system had very very dead cabinets and really detailed mids down to the sealed box rolloff - the cabinets were two shells - 1/2 plywood inside with interior bracing of 1" aluminum struts with 1/4-20 threaded rod inside those, the threaded rods drawing the plywood together and then the tubing filled with GreatStuff. Those assembled boxes then we glued inside outer shells of 1/2 MDF and veneer. Cabinets for these new speaker liner boxes could be rolled into the new kitchen cabinet order.

But what line level crossover frequency makes sense for a 6.5" and 4" ? Can I clean the kitchen drives of accumulated grease without compromising the surround ? What else about this project doesn't add up ?
Getting rid of every bit of old stuff to the makerspace and buying a pair of Elac or Wharfdale bookshelf speakers would probably do just fine for this if the above is not a good idea.

Thanks for reading !

I am working on this for a friend. The volume pot definitely is bad but sourcing a new one is not working (loudness tap) and wanted to ask for opinions on what I see may be options:
Schematic attached for clarity.
The volume pot is a 100KBX2, I have not pulled it yet but it should be linear taper and of course it has a loudness (contour) tap. There is a 6.8K resistor on the tap to ground with the contour off, add a capacitor in series with it on. The loudness switch is not a requirement.
Possible options:
1) Use a 100KAX2 log taper pot and remove the loudness circuit. Just removing the loudness circuit with a linear pot will result in too much signal to quickly, with a log taper that may not be the case?

2) Use a linear taper (or log taper) pot and add a resistor from the input to ground to keep the signal level attenuated. Maybe 6.8K + the resistance form the loudness tap to the input.

I have 2 Visaton W200S-8 units here. I would like to use them as woofers in a sealed three way arrangement. For the mid I want to use a 3" wide range unit, that can be filtered low (say 250-300Hz) at the low end and high (say 4-5Khz at the high end). Thinking of a 3/4" soft dome tweeter for this.
I have worked out the sealed air volumes for the W200S-8, and think to have decided on a volume somewhere between 28.7L (Bessel) and 16.2 L(Butterworth). and erring on the bessel side. Maybe even going below it with 30L total.
Is that a good idea? Any input here is welcome, as long as it remains sealed (I want no smear on the low end).

Another big question is this one: How to choose a sealed air volume for a full range mid mid driver? For instance if I where to use a Tang band w3-881SJF from 300Hz upwards.. what sealed alignment or volume would be appropriate and why?

Suggestions about alternative mid drivers are welcome, as are tweeters or other advice! I do however want to keep crossoverdesign simple as I will be doing it by ear (more ears here though..).

Kind regards!

It’s been a long time guys, I’ve taken a long break from amplifier repair because of the cheap Chinese bullcraps, the fakes the clones and the knockoffs. However a friend bring this to me and I couldn’t resist the good “old school” days….what are the gate resistors used in this amp powersupply and does the IRFP264 are the original FETs installed at manufacture?

If anyone has a set of these in good condition, I am interested.

The TDA7052, with its minimal requirement of external components, seems to offer an attractive alternative to the popular LM386 in applications where high power and very high audio quality are not priorities.

• No output coupling capacitor
• No Zobel network
• No ripple filter capacitor for the low-power stage
• Potentially twice the output power for the same power supply and load impedance

Its limitation is in the power dissipation which is already 0.91W with a 6V supply and an 8Ω load. That's about the maximum for a small DIP package and makes it impractical for operation from, say, a 12V supply with an 8Ω load.

Does anyone know of a type with the same minimal requirement for external components but with provision to mount it on a small heatsink, such as one in a TO-220 package?

Hello all,

Edit: I've changed my pricing a bit. I removed option b, and reduced the price on option c for both switches. See below for details. Quantities are limited.

For sale are two different low-voltage remote switches. The first switch (smaller one #1), was designed out of the need to have a small footprint switch module, that would allow a press ON/OFF function for Ian Canada's DAC stack. More specifically, it was intended to work together with Ian's LinearPi PSU's that already included a Slave Control Input function. Each PSU could be daisy chained together, so that a single press of a switch would power ON (or OFF) all PSU's. I also needed a 'one switch' ON/OFF functionality with LED status for STDBY and ON indicators. Since my recent designs have included mini-ITX computer cases, of various size and shapes, this type of switch would be perfect. The reason for my departure from traditional black and silver audio enclosures to mini-ITX cases, has largely been the fact I was/am getting tired of the same old style cases, and wanted the challenge of developing my case modding skills. And, almost all modern computer cases have a; (1) momentary on/off pushbutton switch, and (2) at least 2 built-in LEDs for POWER and HDD that are brought out to the front panel for easy access and use. These (LEDs) would work perfectly for my application and this switch. All LEDs and switches make use of Molex KK connectors, so that can be user mounted.

Switch #1 - The first switch(below) was designed, and intended to work specifically, with the LinearPi PSU. It does not switch high-voltage, but intended only for low-level voltages. It will work with other low-voltage applications as well. Images are below.



Switch #2 - The second switch is a more traditional switch that includes a 120VAC soft-start feature for large initial current flow. However, the control functions are still low-voltage, and make use of a MO switch, with STDBY and ON LEDs - as used with the smaller switch described above. In addition, to the higher-voltage soft-start feature, this switch also has an independent built-in switch that may, or may not be engaged(user selectable w/jumper) to control an electronic relay with LED indicator when used, or active. This switch behaves as a simple SPST action. For my application, I also wanted a 5VDC supply available as well for use with future projects. The Meanwell (IRM-10-5) power module supplies 5VDC, and is rated at 2.0A. This low-voltage remote switch has found it's way into some of my recent projects, including a new chip-amp, as well as a new preamp board. All SMDs are professionally soldered, except for a couple ICs that I will solder before shipping. A couple images are below.



All LEDs and switches on both boards make use of Molex KK connectors, so they can be user mounted. Instructions/diagram will be included in the your order.

I'm offering these boards in 3 different configurations; (a) PCB with all SMDs (soldered), (b) SMD PCB with bagged T/H components(kit), and (c) fully assembled and tested. Prices are;

Switch #1:
a) $20 - PCB with SMDs soldered
b) $36 - all TH parts bagged
c) $40 - assembled and tested

Switch #2 (soft-start):
a) $30 - PCB with SMDs soldered
b) $50 - all TH parts bagged
c) $55 - assembled and tested

About the pricing... The biggest parts expense is the Meanwell power module. Flat postage of $10.00 for any single switch, any single configuration. Postage cost for 2 or more will be estimated. USA Only. PayPal only.

I only have a few boards of each, so don't miss out. Please PM me if you are interested, or have any questions.

Thanks,
Rick

Hi, I purchased a used set of 6422cfp, and they came with tweeters.

Anybody know what they are and how to separate the unit from the mount frame?

I have a heavy hand and am notorious for oops...

Looking for some insight. Fresh meat here- Need 8 Channel AMP for DIY speaker project. Getting 8X200 store bought etc would cost a small fortune. Came across a DIY amp using 2 L15D with an SMPS500R..
I want to use 8 L15D with a Connex SMPS2000RxE 60V. Doable or is there a better way? Budget build- Amp boards total is like $250 for 8 of them- need 8X200-300W @4ohm clean. The speakers Im building will need 150-200W for the woofer alone- then enough to power the Mid/TW



Links to both-
https://www.amazon.com/.../B07TV.../ref=ox_sc_act_title_1...


https://connexelectronic.com/product/smps2000rxe/

Hi All -
I'm trying to decide on getting back into speaker design and building , at least for one project. Will be glad to hear opinions from the present day. I'll post my query in Multi-way shortly. Cheers

Hello, long time lurker and have had this account for a while but realize I have never posted in this thread so I haven't been able to message other users 🙂

Hi. What Zout would be prefered for driving 13 meter balanced cables? According to spec they should be ca 1000 pF but I measured them with a DE-5000 to be around 1500 pF. I know zero ohms would be ideal but what would be a realistic figure?