Hi everyone ! I have this soundigital amplifier to repair and at first glance it has damaged final mosfets! The abbreviation of mosfets is C2, what kind of mosfet are they?

Hi,

I have just finished designing my crossover for a three way speaker. Now I want to put the crossover in small box which is availble in the upper side of the midrange enclousre.
It´s dimensions are 30,5cm x 12,2cm x 9cm. There the complete crossover should be placed.
I have 7 coils in my crossover design. Two core coils for bass (red), one core coil and two air coils for midrange (blue) and two air coils for tweeter (green).
I have already read the article about placing coils from troels side:
http://www.troelsgravesen.dk/coils.htm

I am now struggeling placing all the coils in the small box without interacting each other (induction and crossover talk wise).
I have greated two suggestions (see attached pictures). Which one you would use?
Can you give me some suggestions what is the best placement?

The new DIYAudio forum face looks good, by any technical standards, and with a few improvements could be close to perfect.

Then why am I subjectively no longer tempted to open the forum and post? It is not the quality of the current existing content, this followed a down path for years now, it's not the bore of endlessly teaching the basics like the Ohm law, it's not the endlessly seeing the same dusty implementations of 50 years old concepts and circuit topologies, it's not reading again and again the same stupid/wrong advice and being tired of rebuking and streamlining the topics.

It's simply no longer having fun to get involved in what I subjectively perceive as an impersonal and unfriendly virtual environment. Or I am getting too old for this ****. Or I need a new hobby.

One to another, I subjectively find the new forum format annoying, which is a nice way to say I hate it. BTW, I am turned off by the ASR forum as well (same software, I infer).

Hey guys, I recently finished recapping a C370. All the caps on all boards have been replaced. No other components have been touched. All swaps were checked for correct values twice. All solder joints were measured for continuity with other joints on the same trace and also checked to ensure there is no continuity to neighboring traces.

I'm trying to get the unit fired up for the first time since the refresh and the following happens (dim bulb tester used):

- DBT switch is off
- Amplifier power button is in the "on" position
- DBT switch to "on"
- Amp power light turns on, DBT no light
~1.5 secs later
- Amp power light still on, something clicks in amp (sounds like relay), dbt flashes on and immediately shuts off along with another click from amp

The last event repeats about once every second.

I don't dare leave the DBT on for more than two cycles of this since I don't know what's going on.

Is this a result of all the caps being fresh and drawing too much current and setting off a protection circuit? If so, what's the solution - just let it click on and off until it settles down?

Or has something gone terribly wrong?

Hy.

I got audes 75w104-4 AUDES
Some time i heard this in 50L vented box but i dont like that only have huge(5db) 50hz hill.
So now i want tray something deeb and loud.
I but i to may room.
Witch type box? vented or bandpass?

Henri.

I need to rewrap the inductors on my Kicker 06zx750.1 class d monoblock car amp as the shielding on 1 has failed, 2nd doesn’t look too bad to where it would malfunction so I tested it on my cheap-o LCR tester and got a reading of .12mH and .32-.36ohms. Does that seem anywhere near right for this amps inductors?

As far as the inductor itself it seems to be a brown(green on 1side) core that measures 40x23x15mm with what seems to be 10awg magnet wire (waiting for wire gauge feeler) it has 35 turns total, 20 1st wrap, 15 on 2nd wrap.

I guess I could just rewrap each core with appropriate length/size/turns of magnet wire and just be done with it, but would like to know what the inductors for this amp are supposed to test as so I can make sure it’s correct. Thx

Hello all,
The amp in my son's car stopped working a while back. We checked the fuses and confirmed that it is getting power. He was going to replace it but we found that you could order a replacement board from Rockville, so that's what we did. We have the amp opened up and the old board removed but before we just slap in the new board I have a question. On each of the long sides of the board there are some tabs that were held down with metal straps to the amp housing. The tabs themselves were not screwed down but they did have a white paste under them. I don't know what these tabs are or what the white paste is but I would like to clean it up and put fresh "paste" down first. It's this some type of heat sync paste or dielectric grease? Any help would be appreciated. I imaging Rockville isn't the only company with this type of design.
Thanks in advance!
Matt

Hello,
for sale a new, never used or installed ACUTEX STR 415 in perfect shape.
160 150 euro+ shipping and Paypal fees.
Best regards
Guglielmo
Italy

Some kind person gave me a pair of Quad988 speakers a few months ago( I had to drive a few hundred miles to collect them). They are now my destination speakers, and hence, I am offering, for free, pick up only, these open baffle projects that got me hooked. No crossovers, I used minidisp.
1. 8”high qts PE buy out woofers and Fountek 2” aluminum full range driver. Mounted in solid cherry OB frames.
2. 6-1/2” PE buy out woofers mounted on a quite complex cherry baffle. Built to be used with 26” Apogee ribbon. Includes rear mounted floor brackets. I sold the Apogee Centaurs from which the ribbons came. Sounds great, if you like open baffle. I put a lot of hours into making these.
3. 4 way open baffle speakers with Dayton N16 tweeter, 3” tang band bamboo full range mid, the same 8” woofer as above, and two 10” GRS subwoofers in a W frame arrangement. This pair was great fun. 3/4” mdf. With baffle covers.
I live 100 miles from anywhere, Andrews NC, but if you are visiting the Smoky Mountains anytime soon, they are on my doorstep.
cheers,
Peter

Did someone here succeed in using a MOTU 8A with a Linux PC? I want to use the MOTU just as an 2 channel audio interface with REW, not for mixing. Preferably with Ubuntu, another Linux or Windows will do as well, as long it runs within VirtualBox.

Please post in thread or message me.
Thanks

Looking for any sizes, but mainly 50 cm^2 sd and 8-16 ohm.

The BMS4550 seems to be a golden standard for 1" based MEHs. Are there any alternatives (with up to double its price)? I really like the Beyma CP755 compression driver, it is a 1.4", so its equivalent would be BMS4554. My next MEH build will use a planar driver for HF, but I still do not want to give up on the classic construction and its higher SPL potential - and I am still undecided whether 1" or 1.4" driver and which one. I think the horn itself can be built in a way that it would work for both dimensions with different 3D printed (or machined) throats.

Short story: Corner line arrays can save space, can eliminate ceiling and front wall reflections, and can be fairly efficient. Using 24 Vifa TC9s, a 3.5" full range driver, a corner floor to ceiling line array was created. The array measures and sounds pretty awesome and achieves the design goals.



Long story: If you read Toole and other research, it says that the reflections that color the sound the most are the ceiling and front wall (the wall behind speakers). Reflections from side walls can add a sense of spaciousness but reflections from the ceiling and floor are perceived as modifying the frequency response.

Horns can be used to prevent ceiling and front wall reflections, but to control reflections at mid frequencies (sub 500 Hz) requires large horns. There are some active threads with folks trying to solve this problem by using cardoid cabinets for woofers, which is a pretty cool way of doing things, but there are problems.

I played with horns for a while and I could get good sound using Altec VOTT mid horns and constant directivity SEOS horns, but the sound was never quite of the peerless variety. The balance of the HF with the rest of the spectrum was never quite right. Horn speakers also tend to be big and occupy a lot of space and this annoyed me. And thus were born some design requirements. The new speaker should:
1. occupy less space,
2. control ceiling and front wall reflections, especially in the lower frequencies (below 500 Hz),
3. have a smooth on-axis response and uniform off-axis response and,
4. be fairly efficient, have low distortion, and have the dynamic headroom to hit 110 db peaks.

Toole kind of gives it away in his book that an ideal floor-to-ceiling line array would solve some of the key issues in sound reproduction in the home (figure 18.3). He describes the Keele CBT array as a practical implementation of an ideal floor-to-ceiling array with perfect drivers.

From here, putting the arrays in the corner was a no-brainer. It would completely get rid of the front wall reflection, and the floor-to-ceiling nature of the array would avoid ceiling reflections also. And I had a room that allowed a corner design.

The next question was the choice of drivers. Keele’s CBT uses a cone and a dome. But his arrays are relatively short. The floor-to-ceiling array would need a lot more drivers, meaning more cost, more wiring, and more worrying about unit to unit consistency.

If a smallish full range driver was to be used, the Vifa TC9 was an obvious choice. It has one of the smoothest frequency responses amongst full range drivers, a low distortion motor, and with Vifa manufacturing it, you could be relatively assured that there would be good unit to unit consistency. There are many designs here on diyAudio that use this driver. The Manzanita OB uses this driver. And many others have used it in their design. Seeing it used in Wesayso’s heroic tower build and other line array builds sealed the deal. Plus the TC9s are relatively cheap and I love cheap 😉.

The construction is relatively straight forward. It’s a three-sided cabinet. The front baffle is as narrow as possible so that the drivers can be as close to the corner as possible. The drivers are flush with the front baffle. I had this design in my mind for at least a year but never got around to building it. Finally, after months of frustration at never finding the time to build the cabinets, I asked my friend John (carpenter) to build the cabinets and wire up the drivers.

John completed the build and the arrays are playing music. They occupy very little space, can go plenty loud, are pretty efficient and very low distortion (each driver is barely moving even at loud levels). Using a single 3.5” driver ensures a uniform off-axis response up to a high frequency, above which the Vifa does start to beam, but it is relatively well controlled. The on-axis response is flattened using DRC software, i.e., automatic room correction. The final result is quite good. Measurements coming up shortly. There is still a long way to go. The EQ is doing a pretty good job, but I think it can be better.

Looking for good used 8" mid/bass pr. for two way ported box. Old Kef, Celestion, Philips, etc or ScanSpeak paper cone (just hate plastic). Recommendations welcomed.

Recently acquired HP330B vacuum tube distortion meter. Since HP part #s from 1950s probably not much help now maybe one of the engineer types on the forum could recommend modern replacements that would work. Meter probably needs to read AC volts up to at least 100kHz (5th harmonic of 20kHz).

I have an Ian FifoPi in one system fed with an Andrea Mori entry level clock. (TWTMC-PPG). Obviously this has its own psu, doesn't get power from the Fifo. The other crystal is a Crysyek. The fifo will still select the correct clock for a given frequency family as designed.

Does the Kali work in the same way?. So I can remove a crystal and replace with a Mori clock. I understand there may be a couple small smd caps to remove also if using an oscillator and not a standalone smd clock. I have a couple of new clocks from Andrea and a Kali to play with.!

I came across this super simple tube-based shunt "regulator" circuit which I think is pretty cool. For use with line amps requiring a clean 15-30 ma supply. It's simplicity gets me wanting to try it using a DC Link for the final 220uf capacitor. The ability to trim the voltage is appealing to me as well as choke input, although I'd trim it then replace the trimmer with a resistor. Also not needing heatsinks, IC regulator chips, etc... is appealing.

Looking at the circuit below it doesn't seem to be a "regulator" at all as it has no solid reference voltage, it floats with mains variation. Is it more like a simple ripple-canceling shunt? Or is it indeed regulating the 2-4 volt drift my house mains might experience? For line amps I'm not really too concerned about the 2-4 volts my house mains may vary, ripple cancelation is more important.

I have a few questions (this is one reason I need to learn spice this year):

1) Is it too simple? (whatever that means) to be a reliable circuit.
2) What effect does the mu of the shunt tube have on the operation of this circuit?
3) I've never seen a 6SN7 used this way, I thought it was a "voltage triode" not a "power triode".
4) The vertical deflection dual triodes 6BX7 and 6BL7 are base-compatible with 6SN7 (6BX7 10u; 6BL7 15u) and considered "power triodes". Would those be more reliable long term? Do I need to have 20u? Would more amplification factor be even better?
5) Is the 2k5 trimming voltage or current?

Discussions about class D audio amplifiers from Connexelectronic

Hello all,
I have recently acquired an olive Snaxo 2-4 that has been reconfigured for use with Linn Keilidhs. I would like to return it to original so I can use it with SBLs.

Is anyone able to advise on component values or have a schematic to share? A good picture of an SBL version would be really useful as well.

Below are some pictures of mine along with values of capacitors currently installed.

Thanks in advance

Martin



Dropbox - HF with values.jpg

Dropbox - LF with values.jpg

Dropbox - LF.jpg

Dropbox - HF detail 1.jpg

Dropbox - HF detail 2.jpg

Hi!

I'm currently deciding what to do with all the fuse holders installed in the case of an old amp I'm repurposing. How do you best fuse an analog power amp with transformer-based power supplies?

There's two independent power supplies, one for each stereo channel, delivering 2x +-50Vdc @ 5A. Obviously, one slow-blow fuse will be placed on the primary of each transformer. That leaves me with 4 fuse holders 🙂

Option 1: Fuse the amp output, in the signal path

Pro: Best possible protection for speakers
Con: Amplifier not really protected against malfunction
Con: The fuse, being essentially a temperature(current)-dependent resistor, will introduce distortion

Option 2: Fuse each of the positive and negative rails, right after the main power supply capacitors

Pro: Protect amp and speakers against malfunction
Con: Bypass capacitors on amp board can still discharge into speakers during malfunction
Con: When a fuse blows, one power rail will disappear, but the amp might continue with just the other rail. This would make the amp clip either positive or negative half-waves. A surefire way to kill speakers. Am I mistaken or is this a real concern?

Option 3: Fuse GND, right after the main power supply capacitors

Pro: Similar to option 2, but would alleviate the concern regarding disappearing rails. They'd both disappear at once.
Con: No protection should I ever run the amp in bridged mode

Option ?: Something else?

I'd love to hear your thoughts. Thanks!

1. original amplifier circuit.
2. after a little tweak Apex ax2022 -)

Seems like it should work? What are your thoughts?

Hi guys,
I am searching for a simple digital panel meter like these:

Blue DC0-500V LCD Digital Volt Panel Meter/Voltmeter New - UK seller | eBay

LED Digital Voltage Meter Voltmeter Panel DC 4.5~30V Small Mini Blue Portable | eBay

Digital-Panelmeter PM438 Panel-Meter PM438 | eBay

They are probably all based on the same chipset anyway.
The thing is, I want to measure a few volts negative to the power supply ground. I believe these panel meters have floating inputs, so should be possible, but I cannot find any information on the negative common mode for the input.
Any of you have experience with these and/or know the allowed input CM?

Edit: some descriptions say something like: power supply 3-12V - must be galvanically isolated from measurement voltage. But that does not say anything about allowed CM range for the measurement input.

tia,

Jan

104 db / watt

400 W AES

copper demodulation ring

https://www.eighteensound.it/en/products/lf-driver/8-0/8/8nm610 8ohm
does it get any better ?

looking to cover about 250 hz to 1 khz

here is what it looks like inside:

Login to view embedded media

Hi,

I'm looking for a matched pair of SJDP120R085, and I would like to swap it with a pair of 2SJ27 (it's not a Typo, it's Yamaha 2SJ27 and not Sony 2SJ28) that I have.

Take note that there are no known design using these 300W Yamaha P-channel SITs, and their characteristics vary a lot (I have come across 16 pieces of these, they measure very different). So, they're probably not for everyone, but if you're familiar with SITs and want to know how a genuine 300W P-SIT sounds, 2SJ27 doesn't show up very often.

Attached is a picture of the SIT (marked 5 and 9 in the photo), as well as their measurements.

Please send me a PM if interested.

Hi everyone.

I bought a Hana SL a few weeks ago, but I'm having some issues, with IGD in particular. I've tried all the various printed protractors (which have worked well in the past), but no luck this time. So, I was wondering if anyone has one of these for sale, or even if I could possibly borrow for a small fee etc? I'm based in Berkshire, UK. Thanks!

Chris

Edit: One of these popped up on ebay so I went for it. I was surprised how far out of alignment I was, as I thought Conrad Hoffman's arc protractor scaled correctly and on high-quality photo paper would be fairly accurate. The SL is sounding fantastic now and the IGD has reduced significantly. Now just to dial in the azimuth...

Hi there,

I know most PA speakers now use DSP. But if I was to include a good DSP, like MiniDSP into my speaker, it would double the cost of my amplifier/signal path.

Im going to use an IcePower amplifier coating around £100, and as far as I understand the cheapest MiniDSP module is about the same cost...?

The thing is, I only need a few notches of EQ. Can it be done with a passive EQ setup? Is this something one can buy?

Thank you!

Hi all,
I have a question about upgrading
Nad 2700 amp.
Where can I get power Capacitors replacements for this old amp?
Power Capacitors 2 x 10000uf – 80v
Power Capacitors 2 x 10000uf – 120v

I found this upgrade kit (which I would probably get) containing
35 Nichicon audio capacitors KZ, FG, FW, KW but power Capacitors are not included.
Any directions or general thoughts about my plan (should or should not) would be highly appreciated.
BTW, The reason for the upgrade is that It makes some dearty sound from the speakers like bad contact sound from time to time. Do you think changing the Capacitors of a 30 years old amp might solve it?

My speakers are martin logan source.


Thanks

Hi, I bought a used 8000p and find the right channel sometimes drops in volume for a short time before returning. It seems worse right after being powered on, once warmed up after about 5-10min it seems to stabilise and not have this issue any longer. I have been testing this by joining the left/right inputs together so they play the same source (in mono). I measured the bias as and found the left channel was almost zero and right a bit higher than expected. Both about 25mV now. I can’t see any overheated components or other damage (the right side +12V dropper resistor PCB through hole is a bit brown on one leg but not bad). Any ideas welcome as to what it could be!

Hello, how can I conduct a test on a PX25 tube with a TV-7D/U tester?
The tube chart contains test data for a CV1040 (which is identical to the PX25) but I can't figure out where and how to place the tube.
Do I need a special adapter for the European B4 it to fit into the UX4 base?
Any help would be appreciated.

I finally found a better power supply transformer match for my endlessly fiddly little DIY linestage/preamp project. Only 5V too high in this case.

But maybe it isn't really too high, taking into account the load presented by a 12AU7 after it warms up and starts to conduct? It sure would be nice if this is gonna be OK now that I have the hum issues worked out.

Specs say max. 300V on the plate.

Downstream of the 100K feed resistors on plate pins 1 & 6, at power-on with cold filaments, for a short time I have 305V.

Quickly drops to around 90V as filaments warm up.

Do the tube specs refer to plate voltage after idle conduction starts? Thus the second uncertainty: if that's supposed to be the unloaded value post-dropping-resistor, is 5V over still acceptable for a few seconds before filament warmup?

Once again, thanks in advance for all of y'all's lovely input on this. 🙂

Per a marketing email this morning, ESS Labs have a one-day sale on the large Heil AMT at $120/ea, limit 2, using discount code ILOVEESS. If you've been thinking about a pair of them, now's the time to jump.

Bill

Question on TL594.

Pins 9&10 go to the amp's PS drivers, but pins 8&11 are connected to ground. Shouldn't 8&11 be connected to +12?


Someone modified the PS drive circuit of this amp. IRF3205 in the PS, PNP/NPN PS drivers. I dont see the drivers connected to +12v either. Both 8&11, and driver transistors are connected on the same trace with a PINK/PURPLE wire soldered back to Ground terminal. I think thats wrong.


Also this amp is using large un-synced TO247 rectifiers instead of the a square & round ones usually found in these amps. The two large square rectifiers are in-tact, but usually these amps have a smaller round one. Photos next.

Board has been repaired before. Looks poor to me. Board condition is poor. Notice heat under transformer. Heat under PS fets. Lots of broken via/pads. I may just move the purple wire and return to owner if that 'works'.

I’ve built a (Deacy-style) guitar amp from the output stage of an 18v 1.5w portable radio (Hacker Democrat Rp34). I’m powering it using a 5v/2.4a powerbank and USB buck booster module set to 18v. I also have a Range Master treble booster in the guitar signal line that can be swicthed in or bypassed. See attached diagram.

The amp is quite noise free when the guitar is silent but when you play notes on the strings behind every note you hear a sympathetic fizzing, fuzzing buzz. This buzz decreases in volume when I touch the inductors on the buck booster while playing. And it goes completely when the guitar strings are silenced.

With the treble booster engaged a loud squealing noise is added in, which seems to be triggered by the lightest of touches on the guitat string and sometimes it will continue to squeal even when the strings are silent.

I’ve tried powering the amp using a 12v DC wall supply the sound is a lot cleaner (compared to the buck booster also at 12v). I am fairly certain that the buck booster module is responsible for the noise and I think I need to filter the power coming from it.

1. I’ve read that a Pi filter - capacitor-inductor-capacitor - might be what I need but despite some research my very limited knowledge of electronics is holding me back. Could anybody recommend a very general starting point for the values of these components? [powerbank is 5v/2.4a, buck booster is 3w max output set to 18v, amp is 18v 1.5w going into a 16ohm speaker]


2. Also I've read somewhere that Pi filters are "not suitable for varying loads" - an amp is a varying load, isn't it? The same website recommends an L section filter "as its output voltage do not vary largely with load current.” Is that correct, should I actually be making one of these instead?

3. Am I missing something else?

I have gotten a pair of LT12 "Wolverine" speakers for basically postage. They work but the main cones are shot.
I have found one speaker parts dealer in Australia list the recone kit as being available from a US supplier.
Yet I have yet to find any dealer who lists or has access to any parts for these speakers.
I can't even get a dealer to help me find an equivalent 12" kit (I can salvage the "wizzer" cones) using the information I have about the voice coil, spider, etc., for the speaker.
These are nice speakers to work with and I can't believe there is no way to get them reconed
any idea would be great

A little smoke and a blown fuse, low B-

I built a TSE 300B for my adult son a couple of years ago. He and his girlfriend seem to have a habit of turning it on and off without waiting for it to cool off. (I replaced the fuse once before.) He says before it stopped working, he smelled something and then it blew a fuse. The amp has a CL-90 in it, but I’m thinking the quick on-off-on was the cause of the problem.

I replaced the fuse and put in the tubes and started it up; one of the bias meters went to zero while the other was pinned and then the fuse blew.

I took it apart and looked at the circuit board and didn’t see any problems.

Next, with only the rectifier tube and the 5842’s in place I got a B+ of over 400 and a B- of 170 and then after a minute some smoke. This time I checked and the solder around R25(36K, 3W) was burned off.

Am I correct in assuming that the problem is the low B- and that the either D2 or D3 (FRED’s) are bad?

Any suggestions on how to troubleshoot?

Thanks, Jacques

I'm currently building a DG300B and want to use relays to change between three output options: 4 ohm OPT secondary, 8 ohm OPT secondary to binding posts, 8 ohm OPT secondary to an XLR headphone jack.

The amp is rated at 10W. Would a 2A signal relay be sufficient, assuming the output would never be switched while the amp was outputting?

From what I've read, higher power relays have issues due to needing a minimum load current to keep the contacts clean, whereas signal relays avoid this issue?

Hello!

I'm building an analog stereo amp that can be switched to bridged mode. i.e. a 4-channel amp with a switch on the back. Each channel shall have it's own DC offset speaker protection, so I'm looking at 2x stereo protection boards.

This protection board I'm looking at. They state "Stereo module for 2 channels. (not bridged because GND common)". I'm going to copy the shown wiring diagrams here:



This leaves me confused. It would force me to buy 4 instead of 2 boards. Why is the bridged setup different? Bridged amps share a power supply, so they share GND on the power input and speaker output anyway. I just don't use GND as a speaker output, that's all.

I'm assuming the module measures DC between D+/D- and G+/G-, and has the relays switch D+ and G+. In bridged mode, the speaker would plug in between D+ and G+. If one of the amps blows, a DC offset may appear between either D+/D-, or G+/G-, triggering the protection module and breaking the connection to the speakers.

So what's up with only using half the module in a bridged setup?

Thanks a lot!

I'm preparing to DIY build a Line Array pair of speakers, being convinced with:

- their cylindrical dispersion
- more efficient with distance vs point source
- multiple drivers equal less cone excursions needed - huge argument IMO
- better heat dissipation with multiple voice coils vs one larger driver

Now, I want to use about eight, full range drivers with no crossovers and ideally no sub. Inspiration came from Grandinote Mach designs. Of course, there are many other LA models, but most use crossovers - I prefer to avoid them.

Perhaps only the top one driver or top two drivers could be mounted in an open baffle? - something to consider later.

I need help in choosing the right drivers.
Goals are:
(1) bass going to 40 Hz, but if it will be 50 Hz , hmm maybe i can live with that
(2) best as possible transients, microdynamics, the lowest distortion
(3) more pistonic

As its usually the case in audio, goals 1 and 2 are hard to have together so as 2 and 3.

For 40hz bass i will most likely need eight larger drivers? 8 inch, 6.5 inch?
What if the Line Array will be positioned in room corners forming a type of horn? Very wide baffle gives +6 db, while a quarter volume of space should improve low freq. by approx 9dB, right?

Can it be done with 5 or 4 inch drivers?

Transients.
Here is a good presentation by founder of german Gauder Akustik
YouTube

Since accelaration = Force / mass.... i'd love to have very low moving mass.
Some smaller drivers have like 2-6 grams moving mass which would be excellent.
However, they are made of paper bamboo or aluminum.

The guy from Gauder is saying that ceramic drivers are superior in terms of impulse response to all other cone materials. However, ceramics/alum have a resonance peak at 7kHz and i dont want to use crossovers to avoid that peak.

My main questions is: are ceramic cones in general better in terms of speed, transients even when they weight 20-30 grams vs smaller 2-5 grams paper cones?

Or maybe carbon fiber drivers will strike a good balance of all these qualities?
For example:
Dayton Audio CF120-4 4-1/2" ? it has freq resp. 50-15khz and mass 6.8gram

How about Tang Band W3-2141 3-1/2" Paper Cone? Cone mass only 2 grams
resp 75-20khz.
Price is similar about 30 bucks.

Your input greatly appreciated!

Let’s say spec calls for 2.08A. If I get a transformer they produces 2.08A even, is that fine, or should I leave some buffer? Get slightly bigger than what I need?

I wasn't sure where to post this one.

Before the idea was a thought I always liked that Les Paul design. Every stage of the making looks perfect. Very cool Login to view embedded media Login to view embedded media

Hi. I'm dealing with a Pionner SA 408 amp. I want to recap it, bias it and so on. I've attached the schematic.

Almost all electrolytics were Elna caps (dark blue ones, they label says (RE)). The main power filtering were Nichicon and the small ones were also Nichicon.

Here a pic of the main board (preamp & amp section):




And here a pic of the phono preamp (right) and power supply section (not complete):


This is my recap so far:

C53 & C54 Nichicon UPW. These are the two big power filtering ones

C49, C51, C52, C53 & C56 Panasonic FC. All these caps are near the big power supply ones except C51, which is in the phono preamp section.

C1, C2, C11, C12, C46, C47, C31 & C32. All of them were electros. Since they are small values (220nf, 1uf, 2.2uf & 3.3uf), I put film caps there.

In the remain positions I've put Elna Silmic II

For what I know, there's some debate about what is in the signal path and what's not. Since it's not that clear, I made my best based on my little knowledge. But I might be wrong about some positions, please let me know if should do some changes.

There are plenty of ceramic capacitors all around. Should I change some of them for another type of cap? There are lot of small ones (47pf, 68pf, 100pf, etc), but there are also some big ones (47nf). I've never come across any information regarding these, so I'm kind of lost here.

I started a thread a couple years ago when I wanted to recap the phono preamp only. Some very nice users gave me advices about what to do. But I got a bit overwhelmed and realize that I needed to learn more. Some advices were regarding the value of some input/output caps. It turns out that these caps are pretty small in this unit. Is it true? Here the thread I meant:

https://www.diyaudio.com/community/threads/pioneer-sa-408-recap-phono-preamp.339995/#post-5846574

About the biasing:

I've dealt with a few amps of this era and all of them had trimmers to set the idle current and to center the voltage at the output. All of them were class AB. In this amp there are not trimmers whatsoever. There are not big caps at the output as well, so I guess this is a different design. Any ideas about what can I do?

I really appreciate any help. Just trying to learn 🙂

Cheers!

For sale: Two Alpair 10 Gen 2 speakers.

I'm the original purchaser. Never used.
$125.00 shipped in USA for two speakers. Double boxed. Paypal.
Thanks.

I am the original purchaser of this tube amp kit. Through chip amps, Tubelab projects, commercial items, and other avenues, I never built this kit. The plastic bag the PCB came in is open when I inspected after purchase but that is all. The kit is complete. It’s been on the shelf and the downsizing is in full swing.

Currently unavailable commercially but here is the link for more information.

http://www.s5electronics.com/gtube.html

https://tubedepot.com/products/stereo-tube-amplifier-kit

Some build notes: https://wa5znu.org/2009/12/K12G/

DIYaudio thread: https://www.diyaudio.com/community/threads/s-5-push-pull-power-supply-upgrade.126955/

http://www.s5electronics.com/gstereo.html

$150.00 shipped in the U.S. paypal only. Thank you.

Hi

I'm back...

Its up and running, now I'm hoping I can "improve" on it.

Put it all together in a "box" which makes it a bit easier to move around. The amp has a 1M pot on the volume - I've attached schematic. Given the lower impedance of modern sources and the high output of them, I'm wondering if lowering the value of the volume pot will help in reducing the "brightness" of the amp? I put a voltage divider on the input signal to try and reduce the incoming signal strength ( brought the 2v down to a 1.4v...) It helped a bit with the overall distortion, but I'm finding it a bit bright. I removed the tone controls, but will be putting them back in with a bypass switch should I wish to not use it anymore. I realize I can change the tonal signature using those, but seeing as I want to replace the 60 year old pot with a new one anyway, thought I would see if a different value would help. And ideally, I would like it to sound good without any tone control.

Reading about potentiometers and input impedance is causing me a bit of confusion, which is not difficult to do. Any experience you might have to share would be greatly appreciated.

And, I'm thinking of adding another output tube on each channel in order to increase the output signal strength so I don't have to "push" the amp so close to distortion levels. I've been looking at schematics that have EL84's run in a parallel SET configuration and it seems like it might be possible to do with this amp? I have the space for the extra tubes. Guess I'm wondering if the output transformer is going to be able to handle the additional power? I have no idea what the output transformers are rated at unfortunately.

Thanks for taking the time to read through this.

Per

Not the most urgent issue, but it keeps annoying me.

I prepare an image with a clean white background. 100% white.

When it renders in the forum image-view, there's a big shadow on the bottom. I checked my source, 100% white. And when I open my image outside the forum viewer it is 100% white. But my eyes and several tools say there is a shadow. And it is 3/4 white where I put full white. That's a 2.5dB display error in audio terms.


Yes I can open images outside the forum. But in recent days I have seen screen-grabs which appeared to be shadowed twice. One (not here) appeared to be 25% white bottom shadoow for no reason except screen-grabs. (No we can't teach all e-geeks how to handle images nicely.)

Is this a simple option that can be set off?

Hi everyone,

I recently obtained a NAD 3240PE for very little money. It had some dirty potentiometers and switches so I desoldered them and gave them all a good clean in the ultrasonic cleaner. However, I made a very (very) stupid mistake while soldering back the switches. Everything was fine, except that I appear to have shorted two pins of the output selector 🙁 😡

When I turned the amp on, it burnt a 3R3 resistor (R462) and blew a fuse. I replaced the resistor, fixed my soldering error, and now I measure -70,3V DC on the output of the right channel. Now, my electronics skills are not that great (I'm stil learning but it's a lot to take in), but if I understand correctly this means the Power Envelope circuitry is triggered to supply high voltage to the output stage, and the output stage may be shorted?

My question to you is; has anyone seen this problem before, do you think it can be fixed (given that I would be able to find replacement transistors) and what would be my best next step? I've printed out the circuit diagram and components list which I obtained from HifiEngine but I'm not (yet) good at reading schematics. All I see is a load of transistors... I am willing to learn!

Thank you in advance.

Hi all…

I recently picked up an UPL with what seems to be 2/3 of the 96kHz digital interface, because someone rather inconsiderately swapped the front panel with that of a unit without the front panel digital jacks…!
Does anyone have some photos of the front panel digital I/O jack board? I’d love to be able to somehow roll my own front panel board. I guess layout shouldn’t be that critical right…?

Thanks in advance…

FYI, my new 2-way design has been posted at my website:

http://www.geocities.com/woove99/Spkrbldg/Usher_2way/Usher_2way.htm

Any comments are welcome!

I want to make a violin amp, that will consist of an encosure with single channel amp (a 60 watt class D amp) with one or two full range drivers.

Given that the lowest note of a violin is 196 Hz, I beleive that interesting compromises can be made.

I think a drivers is a good choice, because "lack of bass" will not be a problem, and small drivers tend to have better directivity.

Here is my list of candidate drivers so far:

• Tang Band W4-1320SJ https://www.parts-express.com/Tang-Band-W4-1879-4-Full-Range-Driver-264-903
• Tang Band W4-1879 https://www.parts-express.com/Tang-Band-W4-1320SJ-4-Bamboo-Cone-Driver-264-847
• Seas FU10RB H1600 https://www.madisoundspeakerstore.com/approx-4-fullrange/seas-prestige-fu10rb-h1600-08-4-full-range/
• Faital FaitalPRO 4FE32 https://www.parts-express.com/FaitalPRO-4FE32-4-Neodymium-Professional-Woofer-16-Ohm-294-1122
• LaVoce FSN041 https://www.parts-express.com/LaVoce-FSN041.00-4-Neodymium-Full-Range-Woofer-8-Ohm-293-711

The problem is that I have heard none of them, so I am only discriminating by specs, and the critiques I have read.

Idealy I would try and hear them all, but I thought I could perhaps get recommendations from this group, and if the list can be shortened further, perhaps I can order the best two or three and do listening test !

This relates to the renovation of a vintage 1940/50's PA amp with an 807 PP fixed bias output stage that included a rarely seen PP grid choke. The original amp didn't include feedback but I am aiming for a 'presonance' control that will need some frequency management of feedback to ensure stability, even though feedback level is circa 6dB max.

A draft schematic of the modified PI and output stages is shown below. The 2TU6981 PP grid choke provides a high impedance load to the PI stage without having to use relatively low valued grid leak resistors (ie. 100k). Each choke half has a high primary inductance of circa 600H at 40Hz, but also a 16kHz resonance from a circa 200pF winding shunt capacitance and a few hundred mH leakage inductance, followed by another resonance at 30kHz, as indicated by the impedance plot shown below. The choke inductance needed some modified PI stage output coupling cap management at the low frequency end otherwise it causes an LC related response peak with the PI stage output coupling cap at what was a noticeable 40-50Hz.

The renovation is nearly complete and the amp happily provides 40W clean in to a resistive load, and about 70W cranked. So now to the application of feedback for the presonance effect. The OPT is nicely interleaved so I am not expecting significant resonance effects from that aspect, and can include some HF phase compensation (across feedback resistor and using some series output inductance) if needed for such a low level of feedback. I need to add in a dominant open-loop HF filter which will be a capacitor across the PI stage anodes, but will get to that once I have the grid choke under control.

So back to the grid choke and how to tame its behaviour. I've just confirmed that there is a dominant 16kHz ringing on a low frequency squarewave signal through the amp. My initial guess is to shunt each choke half-winding with an RC to apply something like a 100kohm dampening above 10-15kHz, as that seems the simplest way forward. Happy to hear of any other options to try and mollify the resonance effects of this grid choke (apart from ditching it 🙄). I should get to this on the bench in the next few days to see how much influence the RC can be, and how much HF roll-off I need for feedback stability.

Tim

Hi folks, I'm on the hunt for a Goodwill signal generator, model GAG-808D.
Below is a photo of a similar model, this is the 808G.
The 808D has a digital LED readout but similar styling to the 808G.
Happy to pay shipping from anywhere in the world.

Most or all internal links I find in posts are broken in the sense that they point to the wrong page. I find that if I cut the page number by about half, then I can find the intended post. Below is one example.

There is a link to a poem found in a different thread

In this post, which is given in the new format...
https://www.diyaudio.com/community/threads/has-anyone-seen-this-front-end-before.209658/post-3001597

...please find a link to the poem; it is the last link given in the post, as part of the last phase, "...(his words, not mine), which culminated in a masterpiece of poetry." Note: the link is not on the first line which also reads "a masterpiece of poetry." This link is in the old format.
http://www.diyaudio.com/forums/solid-state/2309-power-amp-driver-block-topology-6.html#post237453

Clicking the link, you will find that it incorrectly points to this page, page 6.
https://www.diyaudio.com/community/threads/power-amp-driver-block-topology.2309/page-6#post237453

The actual poem is found on page three here,
https://www.diyaudio.com/community/threads/power-amp-driver-block-topology.2309/page-3#post237453

Every link that I've encountered has been like this one.

Anyone out there got a schem for this box? Got one where sone resistors have burned beyond identifiability (and it hums tunelessly).
Cheers, Mike

I don't have enough experience to pick a design direction with confidence!
after letting my project collect dust for what feels like most of a year, I want to pick it back up and as of now, I intend to go the same route I had before, but my shopping cart is gone as is the notebook I was using, so I'm back to the initial concept check, but since I'm a novice with actually finishing speakers I'm not confident in my brainstorming/sketch/prototyping phase like I usually am.
The woofer seems to be the only difficult part of most speakers- it's the size (so it's the box) and watt draw (plus possible venting) so I would love to see what is common with other builders, what they aim to get from the speaker and cabinet, and the type/use of the project. I really feel like I might be doing goofy stuff like trying to aircool a modern motorbike engine in order to run an electric generator indoors.
original idea was something like: ~40-20,000 hz active 3 way with ~ 8"-10 inch woofer with 1-1.65 CF enclosure, probably sealed - easier design tolerances and shallower roll off. Woofer crossed over pretty low to some 3-6 inch anything-but-sealed-back midrange about .1CF enclosure and a 1" dual ring radiator tweeter (the part I'm most sure of).
I plan on hanging these from where I currently have my speaker ceiling mounts, which ATM bear a dissimilar pair frankenstein 3 way made out of a wine case and something that a wine case might be superior to, are powered with a technics sx-1200 6 channel 100w per amp, although I've intended to buy a mini dsp with this order to play around with and possibly integrate in an iterative upgrade, and if I do that will probably build a piggyback box for each channels amps and crossovers.
I am (and was when I was doing this months ago) all over the place with what I should do for the woofer which everything else is kinda dependent on to establish the size and operating framework. Flit between vented and sealed, then ok I'll make it 2 ft-as big as I can stand, then think my original bass freq was a childish guess and up the f3 by 20 hz, change it again. doubt myself, stop for a while. start back in the cycle of indecision.
are the numbers I'm posting logical to everyone else?
feel free to harshly critique the style since it looks like a disjointed lunatics lucid glimpse through the clouds. if desired, I will promptly explain/rewrite any part unclear or disliked by anyone on request.

Hello!
Which of the following resistors suitable for the upgrade of digital section of DAC or CD player? Not for I/v stage.

1) Caddock MK132
2) Takman metal film
3) Vishay naked TX2575

Which one improved the microdynamics?

Thanks in advanced!

Hey,

The headunit in my bass van started to forget everything after turning acc off.
Headunit is Pioneer MVH S520BT. Just over 2 years old. Since its not losing 12V constant i assume it has a problem with memory chips. After taking it apart i found 2 memory chips inside. One is W25Q16JV and second one W25Q64JV. How possible is that one of them is faulty thus it forgets everything after turning off ignition?
I have 0 experience with headunits thats why i thought i look here for help first.
Thanks.

Plz help me repair my sansui G 6000 amp, I was biasing the amp, when the fuse got blown fuse ratings 125v 4 amperes replace the fuse with 250v 2 ampere it got blown too instantly. Then got one from my old sansui it was rated 125v 5A I turned the amp on, smoke came out of left channel probably from a resistance next to petentiometer.

Then I Immediately switched it off, kept the bias settings to low by anticlockwise turned it on. now smoke from right side resistance most probably.

I have no idea what damage did I do the driver board F-2856.

The board looks okay there is no black joint or contact.

plz help me fix this.

here is the video of the last time I checked it
https://drive.google.com/file/d/1BNkQ8OO2RzytRr6PtP-nQAlt-XW_jv_3/view?usp=drivesdk

Hi!
I have 8 subwoofers amplifiers that need a subwoofer signal. I have a 5.1 decoder that outputs 2.2V signal. How can I make it from 1 out to 8 in.
Thanks
//Rian

Amp not powering nor drawing any current at all. Using TL594 and LM358 (Latch). Posting this here while I start to look through these values.....

TL594
1. 0.085
2. 1.121
3. 0.052
4. 0.042
5. 0.035
6. 0.020
7. 0
8. 14.33
9. 0
10. 0
11. 14.33
12. 14.21
13. 1.134
14. 1.134
15. 1.134
16. 0

IC2 LM358
1. 0.002
2. 1.134
3. 0.005
4. 0
5. 7.08
6. 13.25
7. 0.002
8. 14.21

Hello,
I am looking at the Doge 10 MkIII tube amp (integrated)
The amp has a sub-out, which Doge tells me is not low passed (is full range)
The amp has a Pre-in

Could I run a cable out of the sub-out, into the MiniDSP 2x4 (split the bass off to woofers) and then run the mid and high-range output (minus woofer bass) back into the pre-amp of the same amp?

My goal is to be able to run a 2 way speaker with an active X-over using a tube amp.

Then other option would be to split the source through the MiniDSP and then only feed the mid/high into the pre-in of the Doge ... this would be bypassing the Doge preamp section and only using it as a power amp.

I was hoping to use the pre and power stages.


Hope the is clearly enough written! Thanks for your imput / ideas!

I have replaced a pair of RCA clear top 6CG7 with shield with a pair of 1964 6N6P with gold coils, not round spaceship but square getters. They are to me they sound better better than 6N30 DR. or 6N2P I 's
The valves have in gold print a flattened diamond logo 2 factories used this style of logo Foton & Reflector opinions as to which factory made them differ on the internet does anyone have a definitive answer as to where they were made please .

hello guys,

im looking for a diytube get set go pcb or the clemetine boards... if it's used thats fine too.. Please let me know if you have any.


thanks

Hi world!
Very pleasant new look for my favorite audio forum!
My request is in the title, or class D equivalent amplifier (2x mono or 1x stereo)
Regards.

Hi! I have recently been on a hunt for outlets for an extensioncord for my audio gear and i have seen quite a bit of different types of conductors. I have no exprerece when it comes to which type off plugs are best for power cables and outlets, and now im reaching out to you all experience audiophiles for help.

I was wondering what is the best conductor for a outlet? (230V)

Brass
Pure copper
Phosphorus copper

Did you guys also notice the introduction of a rating system for members, with levels and metal colors?

This makes me puke. I am halfway out of here.

Hello dear DIY-Audio-Members,
I´ve recently bought a good working M-Audio DMP-2 for 30€ and would like to mod the phantom power. I´ve measured only 40V and it would be great, if someone knows a good way how to modify the DMP-2, so it puts out 48 (+/- 2) Volts. I´m experienced in soldering, but I don´t have a schematic for this unit. I have a lot of pictures of the board, if it would help.
Does someone have a solution?

Thank you and greetings from Germany,
Jan

Hi

Somebody brought this amp to me saying that it is totally dead. Upon checking I realise that it is using a "ICEpower 125AX2" module, a class D power amp combined with the SMPS. I injected a signal directly to the power amp and it is working. There is no power to the preamp board. There is a 3 wire cable coming from the module to the preamp board and it connects to the 7915 and 7815 fixed regulators. There is totally no voltage on these wires. I guess if I can provide the +15 and -15 volts to the preamp, then the amp will work. I cannot source the schematic for the module, only the preamp schematic can be downloaded (attached). The module is a smd board and looks very complicated to me. Instead I was thinking about providing a separate +15vand -15v just for the preamp. Will this work and will it cause any interference to the SMPS. Please advice.

Thanks

Hello there.

I have a NAD B326 integrated amplifier with some trouble.

Shortly after i turn on the amplifier, I start getting some poppings sound, from both speakers (at different times). They somehow seem to get louder the longer the amp is turned on. The sound occours independent on volume level and source.

One of the caps in the power supply has started denting on the top, so it might be this cap. Maybe some discharging? However, I would have expect same pops from same channels, if this was the case..

What can this be?

Some people say that these are "The Dogs B....s" (as we say in the UK). I don't.
If anyone would like them/some for cost of postage, they are welcome. These have come out of 'classic' CD players, so I believe them genuine. Please contact me via the PM system.
Best wishes to all.

What usually kills the high frequency in a room?

What treatments are recommended to preserve the high frequencies?

Here is my expert (amateur) take on building the set of MA Pluvia7 bookshelf speakers.

These were hand crafted in a clean and sterile environment using only a Circular saw with an eyeball to guide each precision cut, which results in unique panels, so unique that in same speaker no panels are of equal to any other panel and each have their own characteristics, simply put no panels are of the same size on either of these cabinets.

Both speakers were created with their own method. One cabinet has the finesse and art to it that can only be achieved with slow, meticulous and ignorant method of clamps and glue. Whereas the second cabinet features the ruggedness and strength of screws and a power drill. You could say a 18v power drill resides in its heart as a result. Combined both of these in a pair results in meticulous sound that can never be replicated again.

Each cabinet wall has their own story to tell. The baffle, rear, top and bottom is the result of leftover cement covered hardwood from two year old construction site that was left and neglected overtime in the roof by the experts of roof construction. However, this results in a very favourable position as the width of this wood is an exact width required as per the construction plan. The side walls are another matter and required a journey in these troubled times to venture out and procure from very large establishment, there it lay in its deep slumber and was yanked from the shelf and was taken out to have it butchered.

Here, I present the creation of not so beautifully hand crafted Pluvia7 in its full glory in a tiny form. However, be warned and do not let its tiny form fool you for it is just as heavy and rough as a burning log in deep forest.

Now, you must have an irresistible urge to know, how do they perform?
I have one word for it.

Abysmal.

Hi folks,
First time post.
I have two sets of bose companion 3 on my desk, they have been flawless till now.
One of them now has a scratchy crackle which sounds a little like overpushed input but is there at all volumes of input and volume. Swapped out speakers and inputs but is always there with the one amp/bin.
I’m reasonably handy with tools and hoping someone can point me in te right direction as to what this might be.
Thanks for reading.
Dave.

I’m not 100% what I have here but I know it’s worth something so I’ll take anything reasonable and appreciate not ripping me off LMAO. There are two separate boards here

Hi.. I have a great doubt about power handling of the speaker.
Some brands rate under IEC pink noise test.
Some brands rate under EIA RS 426B.
What is difference between both.😕

Well, what the title says, i want to drive a " """"400w""""" Acoustic USA Spekaer" (16 ohm, actually sounds good with a simple TDA2030 amplifier, guitar high frecuencies are handled well and bass sounds kinda nice but lacks volume, a giant capacitor(4700uF) in pararallel with a resistor at the inverting-input fix this but the saturation of the TDA2030 is notable, speacially bass, like an integrated Fuzz pedal, sounds cool tho)
I just want some recommendation of a chip, obviusly the 400w are fake, and my budget is not up there for building a power supply that big ( i already have a 110-12V 3Amp transformer and a LM350K (Adjustable Voltage regulator like the LM317, but Rated for 3A and in a TO3 package), so anything higher that the 14w of a TDA2030, that supports well low bass frecuencies, and can handle the speaker below will be nice.
The input will be a Simple Passive Bass, if a preamp is needed no problem there, any recommendation, diagram or whatever is accepted, i am not a electronics engineer (yet) but keeping it simple and in the Analog-part of the electronics will be good

Question.....If I have a SS Class A/B vintage amplifier (B&K ST140 for instance)....And it is known to not play well with low impedance speakers (Magnapans for instance)......Could I put a Xohm resistor on the speakers to show a higher impedance to the amplifier?

Hey Guys,

This forum has helped me a lot in learning and building speakers. In the past, I did do couple of build using Mark Audio Pluvia 7 drivers as per below build thanks to Dave's design plans.

Bass reflex: https://www.diyaudio.com/community/threads/ma-pluvia-7-bass-reflex-bookshelf-speakers.354125/

And

MLTL: https://www.diyaudio.com/community/threads/fullrange-bipole-mltl-speaker-build.351281/

I did not keep the MLTL for long due to their size. but, I still have the bass reflex speaker and have quite enjoyed them over the time.

I am now looking at building another set of speakers, as the Pluvia 7s don't quite offer much in bass region, leaves me wanting more. In the past, I did use them with subwoofer, but now I am simplifying my setup and don't want to add subwoofer in the mix.

What are my options for a fullrange speaker build that offers bass down to 30-40hz region and still sounds good up top and in midband? Being in Australia, options of getting the speaker drivers are bit limited and importing can be costly. As such, I am keeping my options limited to what is currently available locally from darcher.com.au.

So far, her is the list of the drivers that are locally available.
Mark Audio Alpair 10p: http://www.darcher.com.au/store/index.php?route=product/product&path=59_60&product_id=95
Mark Audio Alpair 11ms: http://www.darcher.com.au/store/index.php?route=product/product&path=59_60&product_id=99
Mark Audio Alpair 12P: http://www.darcher.com.au/store/index.php?route=product/product&path=59_60&product_id=67

Before I go ahead and order couple of drivers, I just wanted to get the recommendation on which drivers to get and which design to build.

Here is what I am looking for.

• Easy to drive (around 90-91db sensitivity)
• Good bottom end (around 30-40hz)
• Somewhat flat frequency range
• Good soundstage and imaging

For now, I am thinking of building Pencil design http://frugal-phile.com/boxlib/pensils/Pensil10p-plan-140613.pdf with Alpair 10p, but I am open to other suggestions both in speaker driver and box design (apart from Furgal horns), but as said above, in Australia its bit limited. Will the bigger drivers be better alternatives?

Has anyone given some thought to the idea of a diyAudio Full Range Reference Project and groupbuy?

My thoughts were:

A modestly priced driver. Say the FE103/107 or FE126/127. The 40-1197 would have been a strong canidate if it was readily available.

The enclosure would be a simple t-line or folded pipe with dimensions that would allow the use of standard boards so that the woodworking was not scarry.

A simple BSC, a well documented webpage and of course rhe friendly and knowledgable in the forum.

This way, several of use could compare speakers to this reference project and discuss.

Anyway, it is just a thought.

Regards,
GM.

Hi all, when designing your drivers how do you calculate the magnetic field strength "out where the membrane is"?

And what are the values you find there? Many thanks.