I’m new to the site and looking at getting into DSP as an active crossover for my various DIY speaker builds. I mainly make 2-way speakers and am intrigued with using digital to replace analog crossovers. Looking for advice from the group. This strictly for home use and experimentation so trying to keep budget in mind.
Thanks in advance

Greetings. I know that MDF is pretty much standard for speaker cabinets, but I've been reading about high density fiberboard (HDF). I wonder if it might be superior to MDF. Because it's stronger, maybe thinner panels could be used? But maybe it's more resonant than MDF?
Does anyone here have experience with speaker cabinets made of HDF?
I'm about to start designing yet another pair. Any suggestions/ advice is appreciated!

Hello, please help me, I have a sony dav-dz830w home cinema, which does not start, I have disassembled it and I have removed the model 07dav-power-13-mp power supply.
I don't have much knowledge of electronics, but I started by checking the fuse and the transformers, and they gave me the correct values.
Later I checked the voltages with the power board outside the unit, I got the schematic in addition to the board to be able to check the problem.
When reviewing the voltages of the different connectors, I obtained the following values in the CN906, which I think is the one that starts the unit, I obtained the following voltages with respect to the ground of the connector itself or of the EB904, ground signal of this area, according to the wiring diagram the plate.


CN906

Pcont1: 0.01v
Pcont2: 14-15 v (oscillates)
Pcont3: 0.3v
E+4v: 4v
D+3.3V: 3.2v
6v: 8.5v
d-gnd: 0v
d+5v: 4.95v
m+8v: 7.8v
m+gnd: 0v
12V: 11.9v
a-gnd: 0v


On the Cn 903, I have these voltages:

Diat+12 = 11.8v
Diat+Gnd= 0v



In the CN 904 :

+31.5v=31.5-32.6v (oscillates)
+31.5v=31.5-32.6v
Gnd= 0v
Gnd=0v



CN907:

6v=8.5V
P-Gnd=0v
P-Com2=14-14,5 v (oscillates)

These are the values that I obtained with the multimeter, I assume that the CN906 is the one that allows the boot, since it gives power to the main board, the others are outputs for the amplification card, IR, etc.

My first question is if these voltages are correct, on the other hand if I put the power board in its place in the DAV unit with its grounds, I don't have any type of voltage on any of the CN906,903,904,907 outputs.

What can happen?, I have managed to get the service manual and the schematic of the power board model 07dav-power-13-mp.

But I don't interpret it very well, nor do I know what could be happening with this, my knowledge of electronics is limited, could someone please help me.



Thank you.

I'm new here, I hope to find a solution to my problems and be able to share my experience with everyone.

Hello. I am using this for my preamp heater circuit:



I also connect that the output to an LM555 timer that activates a relay and all sort of jazz.
the thing is that i get some mishaviours because of this turn on noise:



if I switch it off and turn on again, looks like this, and everything works flawlessly:



any idea on how to reduce that noise?

is this because of the voltage doubler?
the diodes inside the BR310?
may be transformer inrush current?

THANK YOU!

I love my GFA-5200, and it sounded great. However, I felt it had lost some bass, so I decided to completely overhaul it and replace all the capacitors. While trying to adjust the bias, I caused a short circuit, and the amp stopped working. So I replaced all the MOSFETs, diodes, and transistors on both channels and adjusted Q007 and Q008. All the replaced parts should be the same as the originals. Since I'm just an interested hobbyist electronics enthusiast, I'm not sure if I did everything correctly. The amp is working again now, but the square wave has a slope in the bass range. Is this normal, or is there a problem somewhere?

Can anyone help me find and fix the problem?
I've attached the schematics (I only have the schematics for the GFA-5200b; my unit is an older, simpler version) and the curves I measured with my oscilloscope at 40Hz and at 500Hz (blue is output).

Hi i am 75 yrs old just found this site and see people still interested in the MELLOW MONSTERS I have made over 50 pairs
To share share my original Mellow Monster speaker plans, on Multi-page PDF .included are plans to cut out plywood using a Radial Arm Saw for airtight construction.

I'm on the hunt for the code numbers for the DL18MT. I think I have one but you can't go on looks. It appears to be an EVM18B but it's too new. has a bump plate.

The number stamp is 818-0882
Cone 74186/18099
VC 8997899
Magnet 84851

Hello,

I am a little late in starting on my InDIYana 2023 build, I spent quite a bit of time testing drivers to see which ones would work best for what I wanted to do. For those who do not know, the Midwest Audio Club has an annual get together in Fort Wayne Indiana in April where one of the things they do is have a friendly theme speaker contest. This years is, Mix a =>8" driver to a tweeter <=104mm inna box <=1.5 cubic feet. My entry will be a Wavecor WF223BD01 8.75" woofer, Seas Prestige 27TBCD/GB-DXT tweeter and Dayton 10" passive radiator in about a 1.3 cubic foot box, about 21" tall, 15" deep and 12" wide.

Enclosure front/back/top/bottom will a pseudo translam with me making translam panels then butt joining them with a lock rebate joint. The baffle itself will start out as a 3" thick panel, but more than half by weight will be removed from it by the time the enclosure is done. Top/bottom/back will be ~1.125" thick panels with the sides being regular 3/4" baltic birch panels with ~1/4" cherry thick veneer applied to them.

BTW, I am soliciting name suggestions for this build, so please suggest some!

HI Everyone,
I have a Levinson 31.5 Transport that was working beautifully. The motor/gear for the close/open lid quit working. But it still plays CDs.
Maxon was the motor/gear OEM. I contacted them with the gear number and motor number. The told me that since the motor is 20+ years old
they could not cross reference this motor/gear any longer.
Please, I needing help finding the DC voltage. Or a spare motor. LOL
I believe when the motor stopped working, the power supple for the motor went out also. I am only getting about 2 to 5VDC momentarily when
I hit the open /close button over and over. I believe the motor is bad because I feed it 5vdc up to 12vdc and nothing happened. I tried rotating the motor
armature shaft with plyers and it will not move.

Any help would be greatly appreciated.
Thanks so much for you valuable time,
Tom

I just received some V6 Classics from Carlos at Burson/Supreme Sound. I reached out after seeing a thread on DiyAudio about offering samples and wanting to step my Music Hall 25.2 DAC up a notch or two. Big Thank You!

My Music Hall 25.2 DAC and ph25.2 Headphone Amp have been my daily companions while I work from home during the pandemic so they have been getting 6-8 hours of use daily and I feel I've become very accustomed to how they sound. Everything is stock aside from replacing the stock Electro-Harmonix tube on the 25.2 DAC with a Gold Lion.

Tube swapping was a great cheap and easy inexpensive upgrade for this DAC. The Electro-Harmoni stock tube is what I consider to be on the neutral and dry side. The Gold Lion adds a touch more warmth and romance and an additional sense of spaciousness.

So far I have about +- 20 hours of listening to the V6 Classics which replaced 2 X OPA2134 and 1X OPA2604.

One of the criticisms of this DAC is that it can sound a little rolled off and isn't the most revealing. For me, it's one of the reasons I like it. Prior to the Pandemic, I was mostly a vinyl/analog listener and really only used digital to search out new music on streaming services or on my daily commute to work. Since buying this DAC, I've pulled my CD collection out of mothballs and picked up a decent transport.

While this isn't a review of the DAC, the description of its character it is important because the biggest change I noticed right off the bat is the V6 Classic opamps brought so much more detail retrieval and openness to the sound that I was very surprised what I had been missing all along. I've been mostly listening with AudioQuest NightHawks and NightOwls and I find them to be a great example of the differences between the stock opamps and the Bursons. The V6 Classic is similar to the NightHawks in the sense that it's more open sounding with a bigger soundstage and a bit more even bass response, where the stock opamps are more like the NightOwls being more intimate and more bass-heavy.

Overall, I would easily recommend this upgrade for users of the 25.2 or 25.3 DAC. While it may seem like a steep investment for a $599 piece of equipment, it really takes what is already an overachieving product up to a new level. You can spend allot more and get allot less as they say!

Since swapping is so easy with this equipment, I'm going to give the V6 Classics some more listening time and then reinstall the stock opamps and report back.

Hello, I have been searching to no avail online to answer a question about impedance wiring, crossovers, and amp load. What I have are some very old 70's PA/Musician speakers that I use both for music on solid state amps and my guitar tube amp as well. These old Peavey speakers had a passive crossover that I am working to redesign and things have become a bit too complicated for me. Originally 2x 15 inch 8 ohm woofers in parallel back to the crossover (so 4ohm), 2x 45-ohm horns in parallel back to the crossover (so 22.5ohm) and 2x piezo tweeters which don't have an ohm rating back to the crossover. It's not a good design, and the tweeters im going a different route with which will match the woofers impedance, and I ended up putting in a single 4-ohm woofer instead of 2-8ohm's. I am also making different cabinets. Each bank of parallel speakers has its own signal coming from the crossover, and the negative terminal just daisy chains around all of the speakers. To me it appears that each bank of speakers effectively parallels all the speakers at the crossover. (All passive crossover design's are this way). Does that not mean they are all paralleled? I read in a few forums that speaker banks at the crossover do not parallel and the amp will see them individually so 4+22.5+4 instead of whatever the 5 speakers would be paralleled together. Is this true? can someone clarify how this makes any sense?

Now for the nitty gritty, 4+22.5+4???? okay so I have also read if you are mismatching impedance that you should use similar impedances. Well, those are definitely not similar impedances. The crossover says (4-ohm) on it but I think this (22.5ohm) may have been damaging my old Randall tube amp. Is this safe to run? What can be done? I don't want to wire resistors in parallel to drop the horn bank more, wasting power and heat, I would rather just completely buy new ones that are rated correctly. They sound decent and I have used them for 25 years on solid state amps with zero problems, but the math makes zero sense to me. So to go a bit further on my impedance question, for simplicity lets say my speakers are all 4 ohm 4+4+4 in each cabinet. Say I connect both cabinet's to left and right channels to my solid state amp. Does that mean my amp is then powering all these banks of 4-ohm speakers? would the two 4-ohm cabinets not also make paralleling and make both cabs 2-ohm total now? Its all very confusing to me. I really don't understand how the crossover which wires 3 parallel speaker banks in parallel doesn't do paralleling. I hope someone can help me I am confused. Thank you all!

Hi, interested in Soekris DAC, I consider different board versions and matching parts.
USB not required.

Shipping to Poland, EU.

Thanks,
Dominik

I am wondering if anyone has tried matching these tubes, and if so are the results all over the place? I built a pair of monoblocks each using 4 tubes in PPP configuration loosely based on the Ciuffoli OTL v8.2 schematic. I have 12 tubes and am measuring the cathode current at 145v Anode and at -50 and -55v bias points. I have results at -50 ranging from 50ma to 245ma with clusters around 110 and 220ma. I am going to need probably 8 more to get 2 fairly matched quads. Surely for a military application they can't be this bad?

Legendary phono amp in perfect condition. All electrolytics have been replaced. Im the second owner. See photos for the cosmetic condition.
Not many C models have been made, so pretty rare.

2850€ + shipping

Located in Finland

-Antti

Hi All,

I'm LTspicing my first tube amp dablings. 300B fantasies. I noticed the following:

When the input signal on the grid exceeds the cathode voltage, the 300b output tube clips.
On the 12ax7 input tube however, the grid signal does swing past the cathode voltage. Which is correct? Is this supposed to happen or is this a modeling discrepancy?
Probably common sense to you. Yet I haven't found the answer. Perhaps you would like to point me to the obvious truth. Thank You!

Kind regards,

Ruben

Hello, I would like to build a center speaker as a part of a surround sound system with two/four x 4" fullrange drivers. No tweeters and hence no crossover will be used. The drivers need to sit horizontally . Any tips for the distance between the two drivers? Will a sideways tilt enhance off axis seating experience? Will there be benefits if isolated enclosure is provided for each driver vs all the drivers sharing the enclosure volume? Thanks in advance!

Hi all.

I have a modern solid state active studio monitor speaker that after 25y bit the dust in a glorious cloud of smoke (Behringer Truth 2031a) and was beyond me to repair, especially when it was cheap to replace.
The amp for this was based around 3 x 38w LM3886T. with a bi-amplified design for the woofer and "ferro fluid cooled tweeter".

I thought it might be a fun project and an excuse to read my Merlin Blencowe high fidelity tube amp design book to convert this in to a valve amplified speaker.
My first port of call was to check the impedance of the speakers assuming they would read 4ohm.
The woofer did but the tweeter did not register for resistance and measured a really small capacitance.

My immediate thought was that the tweeter had fried also, but my friend suggested it may be piezo based as they can read like this?

The cabinet is a sealed unit so I haven't inspected the back of the speakers yet.

Firstly, does this sound plausible, and if so how can I test the speaker? Would it be safe to connect it to a consumer audio receiver?

If so can this kind of speaker be driven by valves given that the anode load is normally a product of output traf and speaker impedance?

Lastly if this seems doable would anyone have any schematics or component suggestions I look at as a starting point?

Thanks

on my ebay : https://www.ebay.it/itm/365482429667

Hi everyone, as per title, I need some help in trying to resurrect the amp. was working perfectly until, unfortunately, the speaker terminals, on the speaker side got loose and shorted. massive fry up the PWM session, 3 fried original 2N6488. anyway, opened it up and found more were not in good shape and once removed the bars, I had to go full strip down.

Out of the total 25 2N5488 I could only test 8 good and out of the 2N6491 1, most of the latter broke when trying to remove from the bar, despite using Perry's suggested method. to cut the story short, I removed all from the PWM and output, including the SF163/A and the LM317T/337T. went to local electronics shop and got BD911 to replace the 2N6488 and BD912 to replace the PNP 2N6491.

SF163/A came out good so put them back.

MSPA06 tested on board and all look good.

MCT2V octocoupler also tested on board and seems good. anyway, I wne on and read in the past I could add power with just a barebone structure in place, so I put back the BD911 driven by the MSPA06 for the gate drive and 2x BD911 per rain in the PWM, SF163/A and powerd up with a 12v bulb as safety.

Didn't smoke anything and I got VAC out of the secondary of the main toroid and VDC aout of the center pin of the SF163/A, I only got 1.7 VDC on the SF163 and -2 VDC of the SF163A, this using the driver output GND as reference. also, REM doesn't seem to do anything as soon as I power up the amp goes on.

I tried Perry's trick or desoldering one leg of the thermal protection, but that doesn't seem to change anything on the REM circuit. so I checked again the octocoupler on the left, the R and the diodes, and the 2 MPSA06. all seems good by the reading when checked in diode mode. i have drawn the schematic as best i could, and i ended up with the exact same diagram of what was posted here already. i need some help troubleshooting this nice amp. I know and I'm sure there are better sounding amps out there, but I just love the form factor, the tone, and the looks.
i have a switch to enable REM ON/OFF and I can see 12V or 0 when flicking it.
Power led also not lighting up

original schematics credit to 90scaraudio from this thread: https://www.diyaudio.com/community/threads/orion-2150gx-repair-help.220408/

Hi everyone, I have been developing a 6-in 8-out RPi5 soundcard, and I am looking for people to test it. Please see this thread on ASR. You can DM me on this forum as well if you are interested.

Hello everyone, I have a Mark levinson model "86280-0W690" and I would like to repair it myself since the repair cost is high and I have a little experience repairing but I need the help of someone with experience, my amplifier does not send signal to the speakers, the amplifier turns on and allows you to increase the volume on the radio but does not send sound to the speakers someone to help me I will leave several images of the model

Hello all.
I have InPhase src6 high to low converter.
How can i make bass remote for this?
I can't find it for sale anywhere.

Brüel & Kjaer - Microphone Amplifier Type 2603

From the late 60s!

The 2603 is about 55 years old, it dates back to 1966~1969.

This preamp needs some care, but the overall condition is good, and fair given its age.

Was planning to restore it but never got to it so I'm letting it go.

ASKING PRICE € 575,00 + shipping

There are 6 or more tubes in the circuitry, and as far as I can tell most, if not all of these tubes are still available in case you need a replacement one day.

I have no idea of the condition of these tubes. Neither do I know if the capacitors need replacement. I never switched it on; it was sitting in my music studio as an eye catcher, waiting to be restored one day. All parts are there. And the unit looks well preserved, which is a good indicator.

It could be non functioning, and require quite some work;
It could require just a minimal check up and of you go.

I can give no guarantees. The unit is sold as is.

To know how it sounds, look on Youtube for:"Brüel & Kjaer Type 2603 vacuum tube preamp"

I collected several PDF's of this device and line of equipment, including the schematics etc.
I will happily send them to you (saves you some research)

Please note: this preamp does not work with regular XLR mics - although you could probably mod it to do so.

It does seem to work with line signals as a DI, as you can see from the linked video.

It accepts the following mic capsules from B&K: 4131, 4132, 4133, 4134 ..
Combine the above capsules with a B&K "Cathode Follower" type 2612, 2613, 2614, or 2615.
The above parts are available on Reverb and through other places and sellers.

---

The inputs and outputs require a type of B&K plug that is hard to find. Luckily these connections accept simple banana plugs too, which fit like a glove. The ins and outs are basically (unbalanced) line signals. One could easily fashion a set of adapter cables that go from banana plugs (male) to 1/4" jack (female) for day to day use.

---

Connections are as follows:

"Amplifier input" = the main line input, which accepts a banana plug
The small hole underneath this and other plugs is ground; accepting a banana plug as well
"External Filter Input" = actually an output !! Clean signal from this out
"Recorder" = allegedly this is a more fuzzy / slightly distorted output

---

The overall gain is adjustable by the "Input Potentiometer" and "Meter Range" switch.

---

The power connector is a Nema 5-15R.
Adapters are available to regular IEC etc.
Alternatively you can connect a power cord directly using the screws adjacent to the inlet pins.

---

My location is Belgium. Items are shipped safe and secure with tracking etc.

Please contact me for a shipping quote for your specific location.
I'll be happy to make you a personal quote.

Have a nice day!

Soy nuevo aquí

I am looking at getting a combination GPS chart system and sonar fish finder unit for my 18’ runabout.
Not new to boating but these things didn’t exist when I was younger.
Do any of you have experience and or recommendations?
I also want to know about the SD cards vs built in charts and yearly update subscriptions.

Yes, I am asking elsewhere, I just trust many of the people here more than strangers so anything helps.

I thought it would be nice to have dedicated thread to talk about cameras and such.

To start things off…

On a whim, I bought a $17 manual focus C-mount lens with M4/3 adapter for my LUMIX GX-1. It’s 35mm focal length which gives 70mm equivalent FOV in 35mm format. I wasn’t expecting much, but the lens arrived and it’s nicely built all metal (black anodized aluminum) and laser engraved markings with butter smooth operation. Multi coated lens elements, a round 12 blade aperture. When I installed it on the camera - it instantly transformed the feel and how you take pictures - because both aperture and focus are now mechanical rings and you have to use it just like the old school manual film cameras. I left the camera on aperture priority and applied compensation when needed. Test shots showed nice sharpness wide open at F/1.6 (although very narrow plane is in focus) and superb narrow depth of field to isolate the subject. Nice bokeh - smooth tonality in out of focus regions. Color rendition is excellent. I don’t see any light falloff even wide open. I did not expect it to work so well, frankly. Here are some test shots in the lab. I’m a happy camper. This is a nice portrait lens and it’s going to add another dimension to manual shooting. Damn amazing for $17!

Highly recommended! They make adapters for other camera formats. I chose M4/3 for mine. Here is the one I got. It even comes with two threaded C mount spacer rings to allow macro photography.

Lens looks like this with adapter:

Mounted on the camera it’s quite compact for a short telephoto:

Here is a closeup photo wide open, note the tight depth of field and smooth out of focus regions:

Farther away and still wide open (look at the text on the driver handles):

Color rendition is nice - very accurate:


I can’t wait to use this to take candids or on the street.

The main thing is that it brings back the muscle memory of using my old film cameras. Instead of holding to my eye, I look at the screen to focus. My camera has a magnifier patch to check focus.

I am going to replace the power cord in my preamp. It has a two prong plug and I am not clear on the polarity.

This is a picture from the schematic of the main power cord. Should the hot wire be connected to the prong with the red arrow?

Presenting thread here : https://www.diyaudio.com/forums/pass-labs/349248-singing-bush.html

Please , keep all tech. questions there.

Now , the Meat:

in case of kits , there are 3 elements :

A: Mu pcb with all parts , except mosfet puck and big output electrolytic ; which means - pcb , opto , trimpot , small elco , few MF resistors , handful of 3W MOX resistors , polycarbonat 1uF caps , zener ......... in short - everything , including wire ring and needle connectors (tip: I'm not crimping , but soldering them)

B: SIT gain pcb with all parts , except SIT , of course ; which means pcb , input JFets smd presoldered , reg , elcos , trimpots, Graetz, MFilms , small mosfet , bjts , zeners, LEDs , diodes ....... in short - everything , including wire ring and needle connectors (tip: I'm not crimping , but soldering them)

C: Schade gain pcb with all parts , except Mos puck and Iron ; which means pcb , input JFets smd presoldered , regs , elcos , trimpots, Graetz, MFilms , MOX, bjts , zeners, LEDs , diodes ............. in short - everything , including wire ring and needle connectors (tip: I'm not crimping , but soldering them)


so , 2 different kits (each being Stereo , of course) :

Option 1 : SIT Singing Bush = A+B (with Mu 3W MOX resistor set optimized for THF51/2SK182 as gain part, so 0R4 up and 0R2 down) ....... price 110E**

Option 2 : Schade Singing Bush = A+C (with 3W resistor set optimized for Mos Puck as gain part , so 0R2 both up and down) .......... price 110E**

Option 3 : Should I stay or Should I go SIT or Schade = A+B+C (with augmented 3W resistor set for Mu pcb - one 0R4 group and two 0R2 groups , which covers both SIT and Schade Singing Bush) ....... price 160E**

Option 1 down : just pcbs of Option 1 , no parts , smd JFets presoldered on gain pcb ....... price 70E**

Option 2 down : just pcbs of Option 2 , no parts , smd JFets presoldered on gain pcb ....... price 70E**

Option 3 down : just pcbs of Option 3 , no parts , smd JFets presoldered on gain pcbs ....... price 100E**

For any option above , if you don't want smd JFets ( you have your own stash) , shave 20E from final price

**Paypal fee and P&P , tracked for anywhere - included in said prices


'cause I still have some space in post , here is list of parts :

A - MU PCB:
********

Caps:
1uF MKC Philips - 12pcs
3300uF/16V Pana - 2pcs

Resistors:
MF 600mW - 6pcs
MOX 3W - 20pcs
Trimpot multiturn - 2pcs

Semis:
ZD 8V2 - 2pcs
4N35 - 2pcs

Misc:
ring wire conn.- 2pcs
needle wire conn.- 4pcs
PCB - 2pcs

B - SIT PCB:
*********

Caps:
1uF MKC Philips - 2pcs
10uF/25V Pana - 6pcs
470uF/35V Pana - 4pcs
1000uF/16V Pana - 2pcs

Resistors:
MF 600mW - 32pcs
Trimpot multiturn - 4pcs

Semis:
LED 3mm green - 10pcs
1N4148 - 4pcs
ZD8V2 - 2pcs
1N4001 - 2pcs
IRF510 - 2pcs
LM317T - 2pcs
2SK2145BL - 12pcs on board
Graetz DB1 - 2pcs

Misc:
ring wire conn.- 6pcs
heatsink for IRF – 2pcs
PCB - 2pcs


C - SCHADE PCB:
***********

Caps:
1uF MKC Philips - 2pcs
10uF/16V Pana -4pcs
470uF/35V Pana - 8pcs
1000uF/16V Pana - 6pcs

Resistors:
MF 600mW - 34pcs
MOX 3W - 2pcs
Trimpot multiturn - 6pcs

Semis:
2SK2145BL - 12pcs on board
ZD8V2 - 2pcs
BC517 - 2pcs
LM317T - 2pcs
LM337T - 2pcs
1N4001 - 4pcs
Graetz DB1 - 2pcs

Misc:
ring wire conn.- 6pcs
needle wire conn.- 4pcs
PCB - 2pcs


contact , either via PM , or directly >zenmodiyaudio@gmail.com<

Important: I resorted recently to making pcbs at our Chinese Brothers pcb factory , strictly from quality reasons ( getting tired expecting local fab to get that funny new machine doing Ping! , so I can finally see decent stop lack on my pcbs). Thus - things can be somewhat slower ........ but I wasn't fastest before , so there is no surprise ; slow, but sure ......

Hello everyone,

Joined here in the hopes of having build questions answered! Is the front baffle meant to be sandwiched between the two sides?

When I look at the 5x5 cut plan the front baffle length is 898mm but I'm not sure these measurements match what is on the sheet FH3-1.

On that sheet it looks like the front baffle goes over the two sides.

I cut everything except the sides already so I'm wondering how to do things right!

Hi all,
I'm looking for two sets of FQP3N30/FQP3P20.
They are intended to be used for HPA-1.
EU location is prefered vs shipping costs.

Cheers

I've seen recently a lot of praises for a local indonesian fullrange driver builder called Aurel Bryan. But i can't find much info about it or reports that don't come from Indonesia. Does anybody have any experience with this brand or more info about their drivers? They look wel made i have to say...

Hello,
So I have a trio kenwood ka6004 amplifier, but no left channel. However, when i switch off or power down the left channel prouduces sound then fades away. Why and how to fix please

I have this CD player with strong distortion on both channels like white noise, even with a silent audio track. The player worked perfectly until it was connected to amplifier that I had never tried before 😞. This makes me think of a problem with the analog output or from the DAC onwards, the tracks are read and can be heard. The service manual is easily found online. I started to probe the power supply voltages and apart from slight deviations they seem ok, I have a USB digital oscilloscope available that does not show me the RF signal with an eye pattern. It seems to me that there is a DC component in the output. In short, lots of ideas but confused, can someone give me a hand?

[UPDATED: Workbook here - Google sheets workbook with all the information organized.]

I've done a bunch of google searches and not found too much on this particular amplifier, insofar as repair and upgrade. The power caps have leaked, and one of the power fuses is blown. I have the whole amp apart which is in otherwise beautiful condition. I'd like to replace where prudent (while I'm here) and upgrade where that's sensible.

• 15000 uF Nichicon caps are here now, and all leaking. Suggestions here?
• I'm wondering about the electrolytic caps that are here, while everything is open. Replace? Suggestions?
• Any resistors I should be considering for upgrade?

I have been in the market for an HCA-3500, but the right one has yet to show up. That seems to have some good information for the DIY guys. Unfortunately I've not been quite so fortunate with this model. Any input is kindly appreciated!

Filippo

Hi all! I've been a long time forum lurker, but now hope to participate and engage further. I've been an audio and gear enthusiast for the better part of the last 30 years, and have started performing light electronics repairs in the last few years. As my skills have increased I've started taking on new projects as I have no shortage of old gear to work on. Thank you to everyone who have unwittingly helped me so much over the last few years, and I hope to engage with you all here further moving forward. Cheers!

Two VRDN boards for sale, fully working as I used them for my DAC.



Asking EUR 30 each or EUR 50 for both plus shipping to The Netherlands.

Hi guys, i have two modules icepower 1000asp damaged with high voltage, so exposed some components. Anyone can say the code of part number of TA218 and TA210

I have 2 pairs (4 units) of 10” subwoofers, ADS S10. I’m going to install them to my car. However, only one pair is original, the other has been repaired (new voice coils replaced). I will use a Soundstream reference 405 to power them. This amplifier is capable of driving 1 Ohm load on subwoofer channels. However, I’m wondering if I should install all of these four subwoofers in my car, or should only use one good pair. Because I’m afraid if the repaired pair will make the sound worse or not. But, the crossover frequency for subwoofers will be (always) set below 200Hz, so I’m not sure if the repaired subwoofers will affect sound quality of the whole system. Please share your thoughts.

Hello

I have a Bryston 4B-SST clone kit for sale, it never being assembled, all part are include, but there was no output power transistors included in that kit. So you will need to buy the output power transistors.

I did not buy the preamp and the power supply, so there is NO preamp and NO power supply in that kit.

The price for that kit are $ 80 plus the shipping cost, I sell only to a canada buyer, because shipping outside of Canada are too much troubles and cost a lot.

You need to have some good experiences in electronic to do that kit, I can not help you for the asssembling of that kit.

I include a cd of the instructions and scematic. Everything will be well packed in the original box, as you can see in the photos.

Payment can be made by interac-e-transfer

I live in Quebec.

Gaetan

Hello,
Yes, so it is not audio use, or not directly.
In my turntables, I'm using a double DDS generator to run my Airpax/Premotec motors. For that I'm using LM3886 based amp modules, 2 channels. That is not a straight choice I think, I had some ringing problems before I've inserted 2 antiparallel 47uF caps at the output of the chipamps, but I always wanted to try TDA7293 because I saw some others use those without problems.
Now I need a 3 channel amp (also building a 3 channel DDS gen) and there is no ready made 3 channel module, so I've decided to make one. I have power supplies, so did not put it on the board, but plan to use a simple Graetz and 4x 22mF caps.
So, if you have experience with these chipamps, would you have a look?
As I know the feedback resistors has to be placed the closest possible (some even solder on the IC legs) and obviously in/out has to be separated. Any other thing to watch?
On other threads, there was links to a document listing pitfalls in implementing amp with TDA7293, but the link does not work any more :-(
Thanks!
JG

MM PHONO RIAA Preamplifier - KIT - A very good preamplifier that sounds very good compared to many transistor preamplifiers. Much discussed on many forums and built by many of our colleagues.

Kit for building PHONO RIAA Preaplifier with tubes russian 6N3P-E (high quality audio grade, 5000+hours life). Is a stereo variant - for two channels one single board.

Variants:

• complete - all components and tubes - assembly - 65EURO + 15 Euro shipping to EU.

I am sending to EU only.
Note: NO power transformer, NO case.

https://postimg.cc/SJJbCJP0



Attention, electronic tube mounts work with dangerous voltages that can cause death if you are not careful and do not know how to use them.

For more details, please send me PM.

Purchased on December 2024. Used 3/4 hours.
350 €

If I connect 2 amps to 1 speaker what are the dangers?
I use a a big-box Blue-Ray receiver to power my 4.2 system. I may love my subs but my neighbours are not impressed. My original satellites have been replaced with bookshelf speakers. Turning subs off at night is not a good option as the crossover frequency is too high (120hz).
I have no plans to use 2 amps at the same time. When my home theatre system is off I want another amp to provide a full range signal to the front satellites.
Is this okay?

PCF 802 KIT - PHONO RIAA Preamplifier

Kit for building PHONO RIAA Preaplifier with tubes. Is a stereo variant - for two channels one single boards

Variants:

• only tubes - 25EURO + 15 Euro shipping to EU. I am sending to EU only.
• PCB - tubes - sockets - 50EURO + 15 Euro shipping to EU. I am sending to EU only.
• complete - all components and tubes - assembly - 65EURO + 15 Euro shipping to EU. I am sending to EU only.

Note: NO power transformer, NO soft start function, no power supply module

Attention, electronic tube mounts work with dangerous voltages that can cause death if you are not careful and do not know how to use them.

For more details, please send me PM.

Link with photos: https://postimg.cc/gallery/yHGGGJB

I'm looking for a dual SMPS with approximately +/- 30 volts and 30-60 watts.

In general, it seems very difficult to find dual SMPS with voltages of +/- 18-32 volts and 20-80 watts.
If anyone has any tips or sources, I would be very grateful.

Hi everyone I am a dj and some times if I can I do gigs but the problem that had came to me is that some cafes or plases that I dj dont have any type of speakers. Now the problem is that i dont have my pa and where i live there is not a lot plases where I can rent pa system so I was thinking that I could build a pa system out of them until i dont have enough money to buy some better speakers. So what do you think is it a good idea or not and i will anyway build a box for that speakers so i dont have noting to lose.

Hello everyone,

I am planning to build an active 3-way loudspeaker. I would like to use four side-mounted woofers (10 inch), two midrange drivers (6.5 inch) and an Air Motion Transformer as a tweeter.

Everything sounds quite normal, but why two midrange drivers? I would like to have a wide horizontal dispersion, but a strongly focused vertical dispersion. To achieve this, I don't want to use the “classic” M-T-M arrangement, but bring the two midrange drivers closer together and place them directly above each other (about 18 cm distance between the centers of the drivers) and place the AMT directly above them. Due to its design, the AMT already has a strong vertical directivity with a wide horizontal sound dispersion.

I plan to use crossover frequencies of approx. 80-100 Hertz and a fairly low 1150 - 1200 Hz. My own calculations based on Excel templates from the forum have shown that a crossover frequency higher than 1200 Hz could cause problems with unwanted lobes in the midrange.

I have not yet completely decided on the drivers. I have the following favorites:

• 10-inch bass: Purifi PTT10, SB acoustics WO24-TX, Scan Speak 26W
• 6.5 inch midrange: Purifi PTT6.5, SB acoustics MW16-TX, Accuton C173
• AMT: Mundorf 197PP27R-7

You can find a very simple concept sketch of the speaker from the front and from the side in the attachment. B = Bass, M = Midrange, AMT = AMT 🙂. I am thinking about dividing the loudspeaker in two cabinets per side to make it easier to handle. The thin lines in the back have a recurring distance of 10cm. Hence, the loudspeaker would be around 135cm high.

I would be very interested to hear what you think of this concept and what suggestions and ideas you have for improvement.

Thank you and best regards
Klaus

Orders now are open on 'Dark LED' passive filter/IV stage boards, ready built and tested or as a kit for the baseboard with a pre-built and tested filter plug-in. PM me and please don't forget to include your chosen payment method and location so I can quote you inclusive of fees and shipping.

'Dark LED' combines a grounded base (discrete) cascoded stage followed by a 9th order LC filter, then passive I/V followed by a single-ended output buffer, designed to deliver lowest noise. The LC filter does the job of removing DAC images which, when in NOS (no oversampling) begin at 24.1kHz where this filter gives 40dB attenuation. Input sensitivity is +/1mA for 1VRMS out. The grounded base input stage presents a very low impedance to your DAC chip's current output (typically of the order of 5ohm) which helps it give of its best.

Here is how an 18kHz sinewave looks on a typical very-lightly filtered NOS DAC, compared to the filtered output of 'Dark LED' reproducing the same signal :





Preferred payment method is via Wise which typically adds a 2% fee. Our receiving currency is CNY, alternatively USD or Euro. PayPal may also be used, in USD but will attract higher fees, 5.5%.

Price for a Dark LED built and tested unit including top-mounted filter board : 920RMB (~USD128)
A kit with most SMD parts pre-soldered at JLC, filter plug-in pre-built : 720RMB (~USD100)

Physical dimensions: 72mm * 65mm, max height 25mm. Fixing centres : 60mm * 60mm, M3 holes.

Shipping is in addition and depends on your location and speed of service. Courier (FedEx, TNT, DHL) typically takes 8 - 10 days and e-packet four to eight weeks. Not all locations can be serviced by e-packet though.

FAQs

What else is needed to turn the built up Dark LED filter-I/V stage into a fully operational DAC?

You'll need, as a foundation, an existing DAC with a current output, +/1mA R2R chip. A few examples of suitable DAC chips are PCM56, PCM61, AD1860, AD1865 and PCM1702, these all have +/-1mA output in Iout mode. Your base could be an existing DAC board where you wish to bypass its on-board I/V (perhaps a socketed opamp) or maybe just a lash-up on perf-board with your R2R chip of choice. If your chosen DAC chip includes an opamp, be sure that this isn't in-circuit and the input to 'Dark LED' is being taken from the Iout pin of the DAC chip. With a socketed single opamp I/V the DAC Iout can usually be taken from pin2 (-ve input) of the socket when the opamp's removed.

Next you'll need a well regulated low noise power supply of dual rail +/-18V rated at 100mA or higher. An LM317 and LM337-based board set to the correct output voltages will be the bare minimum noise-wise. If you already have a single winding AC supply (an AC wall-wart) then 18VAC at 10-20VA would be in the right ballpark. Use a half-wave rectifier so you get both rails from a single winding or alternatively, a centre-tapped trafo. I don't recommend using switching supplies due to issues with common-mode noise, its very hard to filter out.

Third you'll be wanting some output sockets, typically RCAs so you can connect your Dark LED I/V to your amp or preamp. But your existing DAC may already have these, fed from its own filter stage.

What will I have left to solder if buying the kit version?

The parts JLC hasn't soldered are three NP0 capacitors, several 0.1% thin film resistors, ferrite beads (all 0805 size), SOT-89 transistors, 7mm dia inductors and the through-hole parts which are electrolytic caps and connectors.

What, if anything, is unique about Dark LED's design?

The LC filter is hand-built with in-house wound close tolerance gapped ferrite cored inductors, selected NP0 ceramic caps and the rest of the circuitry uses discrete (bipolar and MOS) transistors to deliver as low noise as possible. To this end, an SE (single-ended) approach is taken with I/V. The name 'Dark LED' comes from the use of infra-red LEDs as voltage references, which are very low noise indeed.

The use of IR LEDs helps reduce intrinsic and power-supply coupled noise meaning that a heroic ultra-low noise PSU isn't required, LM317/337 deliver satisfying results sonically at around 20uV audio band noise. Some technical background to the design can be found on my blog : https://www.diyaudio.com/community/threads/i-v-stages-and-noise.391189/post-7146239

I had a look on the market, did not find one, so we built one. 🙂
We have designed a small form synchronous rectifier, aka ideal bridge, using modern ultra low Rdson mosfets.
It started as a small side project, but the results are so good that we want to put this in production and make it a standard product.
The advantages of such bridge are very well documented:
Active rectification - Wikipedia
http://www.ti.com/lit/wp/snva595a/snva595a.pdf
Synchronous Rectifier Circuit | Active Rectifier | Radio-Electronics.Com
http://peufeu.free.fr/audio/alim_mos_diode/


Linear product presentation.
https://www.youtube.com/watch?v=x74SSPgKiNA

While this video is about automotive product, the principle is similar.
https://www.youtube.com/watch?v=X5qFJ5XNi9A



Specifications:
- operates from DC to 600Hz
- AC operating voltage 6Vac to 51Vac
- DC operating voltage 9Vdc to 72Vdc
- Iq = 1,5mA
- continuous load current up to 16A or more depending on mosfet configuration.

Do not use centre taped transformers (and centre taped used as main reference ground).

The price will start from 35euro and go down with volume as we get parts in lower price.
Up to 100 units - 35 euro
Up to 200 units - 30 euro
Over 200 units - 25 euro

GB google spreadsheet is open till 1st March included
https://docs.google.com/spreadsheets/d/144EP7ZezFLFgZeNq8q8LCgoa5Lb6z94TKbopFC7S6aw/edit?usp=sharing

Regards,
Tibi

I assembled the following revision of the light version of the board, three channels of 100W PWM DAC with DSP ADAU1452.
Since there were some changes to the board structure, I decided to create a new topic to avoid confusion. Description of the previous version of the board here.


On this board revision, I add three auxiliary ADC inputs and two discrete input/output ports from the DSP. This expands the possibilities of external control of the chipboard.
To coordinate the operation of the ESP32 module and the DSP via the I2S port, a clock frequency detection circuit was implemented on the I2S bus; this was done to eliminate the transient process when receiving I2S data.


An ESP32 module was added to the optical input/output board to implement wireless audio transmission via Wi-Fi and Bluetooth.





Starter projects for Sigma Studio.

Aliexpress sells the Audio Network Transmission Interface A404 module, which supports the DANTE data transfer protocol.



The A404 module can be connected to the 3-Way DSP Amp using the adapter I assembled.



This solution, using Dante software, allows you to transmit two stereo channels to the 3-Way DSP Amp via the Ethernet.



The price of the 3Way DSP Amp + adapter board without the DT AES67 module is $105.

Attached to the post is an archive of a folder with files for the starter project for Sigma Studio.

This all started with my 'Convergence' project on a quest for a great bandpass design using a PR as the exit. Initially it was a TB W8-1445A (one-off production sample from the Tent Sale, and also this next item too) and an Eminence 12" PR. I wrote up the project here:
Techtalk Speaker Building, Audio, Video Discussion Forum

I had enough output with the 200W, but the extension on the bottom was lacking. It was made known to me of a commercial company, James Loudspeaker, that sells this kind of design commercially. This only fueled the desire to make this a viable little monster. It was well liked at InDIYana 2017.

Then I went to dig deeper...

I got a UM8-22 and RSS315PR, removed about a 0.25" for the mounting hole, coined the project 'Overdrive' in the same box, and got a little more extension, but the output then suffered. It seemed like where the amp was peaking out was where the design finally hit enough output on the 200W amp. I had a thermal driver failure in this setup, but ultimately do not know what the initialization of that traumatic event was. It could have been amp clipping, or just an inability to expel the heat being the kind of design this is, but I don't feel it was due to wrong box, or overexcursion. I had a replacement in it after that, and never had a problem up to removing it last weekend to make the retrofit explained herein happen for the finale of this 3-year design process. The models did not predict any issue to be concerned about before commencing down this previous path, and I've had several people review them just as reassurance.

I feel if you have a smaller living room or bedroom and require a subwoofer that either of these above would likely be sufficient, and the box isn't big at all. This was definitely a case for Hoffman's iron Law in terms of output vs Xmax.

And now the finale...

About 6 months ago, I started looking for another upgrade path to improve this design and make it what I want from it. On a whim, I modeled the UM10-22 in the same box, and to my surprise I might add, it basically gave me the same result the Um8-22 yielded in terms of response. The improvements were mainly in Sd, Xmax, power handling capacity, and nominal sensitivity. So- same response, but more and better of the 4 specs just stated. I'd call that a win!

I waffled over whether to take the plunge for a good bit of time, because not everyone is happy with this line of subwoofers. It wasn't until there was a sale on the Yung amplifiers in June that I had to make up my mind quickly. Rory was in town around that time, and we had a discussion about this project and the possible options, and he felt my aim was true. I had a lengthy exchange with MattP at PE via PM about the possible reliability concerns of both the amp and the woofers because he has had them himself, and likely not been totally congenial with them. I'm sure he put them to task. He said the 10 was a worthy step-up, and take boosted low end very well. He also said they have not had recent issues with the Yung amps. Since it came from the horse's mouth, I was reassured and bought the Yung SD500-6 amp right before the sale ended. I then picked up the UM10-22 at the Tent Sale a month later for a reduced price.

Now with supplies in hand, I had to modify the box. Most of the time when retrofitting, you just get out the jig-saw and cut a larger hole. Being this is a bandpass, I could not just do that. So after old-units removal, I had to slice off the front chamber of the box. Then I used the former 8" mounting holes as bridge mounts for the false-center. I marked the center using the corners of the box since it's a square x-section, and routed a new rebate, followed by a new through-hole. I marked and drilled mounting holes, and then I biscuit and glued the front back on. Of note- the driver does fit through the PR hole, but barely! I'm glad I had both sides of the driver accessible to position the driver appropriately, or this would have been extremely difficult.

Then I had to cut the new amp through-square, and I'm only lacking about 0.75" in dimension from taking up the entire rear panel. I had to remove the 4 braces I had glued in for the last iteration, and then glued in 2 new braces per side of the box for strength and resonance control.

I used a 4-pole terminal block for connection of amp to driver. There is a bridge connecting the center 2 connectors so that the DVC is connected in series. As for wiring, I wanted something really solid. The UM series takes banana plugs, and I had a set of "polycarbonate locking bananas" and some 2/16 Belden Brilliance wire handy. I used both wires for a net-13AWG assembly per terminal, and CRANKED on them in the jack with a pair of pliers to make them tight. Then I heat-shrunk the banana to jack connection for ultimate durability and keep them from coming apart. I wasn't going to use them for speaker cables, as the locking types tend to break with repeated use, and IMO are kind of a pain to undo and reconnect. I deemed this an acceptable use for them since they would only be attached once.

So- there is the process of this build. Now for the grit in numbers and graphs (see below), as well as some assembly photos of the adaptation.....

Model, along with the amplifier boosted response and inherent highpass pictured below. I found this perusing AVS forum via google looking for just this answer. It therefore does extend below the 30Hz highpass with the boost applied from the preamp board. Note that Unibox is capable of modeling this in segments, and I've pieced this image together to show it in one image.

The finger access rebates are a wise thing to include if you ever think of removing a driver this heavy from a box so small and tight.

Now that the arduous computer modeling was done, and the hair-pulling had subsided, it was time to relax and listen to some music as well as also pummel it with a movie. I have it currently positioned on the floor in front of my entertainment center, just to the left of my right front. I played a movie soundtrack or 2 with some good music songs, and then flipped the phase knob to 180 as something just seemed off. Initiate beat lockdown! All of a sudden it roared to life in my setup. I don't know for sure, but I might have hooked up the amp in reverse to have caused this, or it was just needed to get the summation right. With a 4th order rolloff on the Fenrir on the stands, and the likely 4th order acoustic plus 4th order active rolloff on the sub yielding an 8th order total rolloff, it's hard to say without tearing it back open. The Anthem is at +3 on the sub-out as stated, as it helps to engage the auto-on circuitry that is not able to be bypassed. Gain on the Yung was set at about 1:00, and the xover about 11:00. When I fiddled with it, the sound didn't change much above there due to the inherent rolloff.

I was using the 'Batman and Robin' soundtrack, as I know it quite well. R. Kelly's 'Gotham City' has very dynamic hits, and that just sounded wrong, along with Smashing Pumpkin's 'The End is the Beginning...' never sounding thin like it was this time around. Then there is Jewel's more emotional non-album version of 'Foolish Games' that has a very tonal bass line. Important or not, it's a good disc to own. I then popped Bass Mekanik's 'Download' in to see what it as capable of. 'Out of this World' has a dropping sweep to 10 cycles, and it handled it quite well with a slight Xmax reduction just below the HP rolloff, but it never cut out completely. Then Moonstone with the dominant 27Hz frequency really made this thing shake out the bass. The 8" would have complained, but this thing held its own.

Then I popped in 'Independence Day: Resurgence'. I know the UM8 played this movie with a bit of struggle, but took it just the same. The UM10 on the other hand is a MONSTER in this alignment. I had bass for days and then some. I was really shocked and the jaw popped open a few times because of it. In fact, this is the best bass I've heard since either; 1- I ran Marianas, or 2- Matt ran his dual 18TBX100s. Tight and tuneful, and never sloppy, this thing made explosions in movies sound like they are supposed to. It was fine at the same level setting as the music, but felt it was a little overblown in output, so I dropped it to 12 noon. I'm really pleased with this endgame, as it does what I'd hoped it was capable of doing. Bandpass designs are really low distortion alignments as long as the port turbulence is accounted for, or replaced by a PR as in my case.

Some additional notes:
-If this amplifier is to be placed on a sub on a room boundary, or even in a corner, I would think hard about using the non-boosted amplifier, or even shorting the 2 caps out that provide the main boost on the preamp board by way of a DPST to make it an optional +4dB at 25Hz. The secondary boost is provided by the 30Hz highpass filter at about 1.2dB of gain. I learned this over on AVS forum here, useful starting at about page 3:
DIY Speakers and Subs - AVS Forum | Home Theater Discussions And Reviews

-This 'Overdrive10' design is assumed to be flat theoretically to 22Hz with the boost engaged as-is. The amplifier response profile along with the supposed anechoic non-boosted response above in the model plot, and it should be pretty close, barring room gain changes.

-If making a bandpass sub of this type, or even just a PR box, I highly recommend measuring the tuning with an impedance sweep to verify it is as it should be. Being the nature of the bandpass beast, having it off by 5Hz can really impact the extreme rolloffs of the design.

-Spikes might be a requirement due to how much this thing shakes when it operates.

-Unfortunately, this is not a cheap sub. $169 for the woofer, $90 for the PR, and $238 for the amplifier. I got the PR for $16 and the woofer for $136 at the Tent Sale, and the amp for $200 on sale, not counting the other drivers and passive that I tried out in this configuration. The Yung 200 I had was a door prize at MWAF that started this ball rolling 2 years ago with the Convergence drivers I already had. It's been a long case of R&D this time around.

In conclusion- I'm happy with this version, and will likely leave it naked MDF for a good bit dreading taking it apart to finish it and not have the bass presence for that pending period of time. At a gross volume of just over a cubic foot, I personally have not heard a sub do what this thing can, outside of being in a car. It can be loud, do it cleanly, and plumb the depths. I couldn't ask for more, except maybe a second one! Really though, one is enough.

If you have any questions, please just ask.
Thanks for looking!
Wolf

I could use a little assistance on the step-by-step to bias adjust my HCA-1000A.

I've watched a few "generic" YT videos on this for other amps and sort of get the basics, however the forum posts, videos and articles I've read have not been on this unit, or haven't provided enough detail for me. Some procedures have been close but when things state "measure from the output rectifier emitter" I sorta get lost. I know, I sound like an idiot. I just would like to learn.

I've got a DMM and some 'nads to give this a try, but I need some baby steps. If someone could point out where/what I should be placing my leads I'd really appreciate it, and then I can pay it forward someday.

Long time reader, now wanting to be a more active part of the forum.

I'm mainly interested to learn more about complex simulations of waveguids and bass reflex ports 🙂

Hi everyone,

I’m looking to hire a video production company to create a short promotional video for my small business.

There are so many options out there, and I’m unsure what to look for in terms of quality, pricing, and reliability.

Should I prioritize companies with big portfolios or go for smaller, more affordable teams?

Are there red flags to watch out for when reviewing past work or client testimonials?

Any tips or recommendations would be greatly appreciated

especially if you’ve been through this process before.

Hi all DIYers from Athens, Greece.

I' m selling my best diy project I made 11 years ago under the invaluable guidance of Mr. Nikos Salas.

I tried to use the best components I could afford (and find) at the time, inclusive of a sturdy aluminum case and a toroidal transformer (from a specialist in Poland).

I used silver WBT solder throughout and I made the best solders possible (see photo)!

The phono worked for approx. 18 months with a VDH The Frog (MC-high cartridge) with great results!

For a short period, I easily configured the insides for MM cartridge as guided by Mr. Nikos. Again, great sonic results.

Since then, the phono remained in this configuration but disconnected from my stereo due to a "different hobby orientation".

To be able to re-swap again to MC configuration I prepared a bag containing every component as well as detailed instructions. If I'm correct I didn't omit anything.. 🙂

Unfortunately, I cannot help in any technical question as I have forgotten everything about this project, sorry. Mr. Salas could help here if possible.

I'm asking 800 euros + shipping.

For overseas buyers: you should also provision for customs fees but I don't know if it's possible because I have no selling experience outside the EU and eBay.

Thank you for reading this listing,


Stavros.

For my final bachelor's (EE) project , I've decided to build a battery powered PA speaker.

I am using a single RCF CX12N251 coaxial speaker as a driver and two HYPEX UCD400HG HxR amp modules to drive the woofer and the tweeter. For DSP I am using ADAU1701 board from wondom.

The main question for me is which route should I go in regards to power supply? Because the amp modules require +/-60Vdc (Bi-Polar).

For example, using two LiFePO4 12v batteries, and building two boost converters to boost them each to 60V, put them in series and use the middle point as GND? Ofc, trying to keep the noise as minimal as possible.

Anyways, if you have any experience or similar let me know. Looking for the "best" option for a class D.

Much appreciated!!

Hi guys I have to share my unscientific experiment.
I got bored in my hotel room so I thought I try something crazy.
I pulled the opamps out of my Chinese R2R DAC and also out of my Accuphase c-3850 preamp clone boards from Ali that normally use NE5534 on the input.
Took some wires that fit nicely into the opamp sockets and connected all in in/out fashion.
Result is very good. Dynamic detailed spacious sound.
All is powered by the Jan Didden silent switcher that runs off a 5v power bank. It puts out positive and negative 15v for the Accu boards and 5V for the Dac itself.
Listened for about 2 hours with only using up 1 bar of four from my 10a/h power bank.
I used my phone with USBplayer pro in bit perfect mode.
Absolutely stunning without any expensive opamps involved.
Gain is very high but for road use I will put the volume pot between the two Accuphase clone boards
If I use my tube amp I can probably get away with using only one Accuphase board.

Hello,
My name is Miko, and I'm excited to join this forum. I'm passionate about music and vacuum tubes, and I'm always eager to learn more about DIY audio projects.

Greeting to everyone,
I am a HIFI enthusiast for many years, but now want to built something myself.

Let's see what this journey will bring 🙂

Best,
Thommy

Hi all. Lately I've been working on a hybrid MLTL box that has a single 180 degree bend with no filling, just a completely empty duct to experiment and understand what happens inside. Previously I had built a BR box using the same speaker (without tweeter and without crossover). In both cases I made some measurements with REW obtaining graphs of SPL, distortion, harmonics and impedance, obtaining different results. I wanted to compare my results with those obtained by other people who have built transmission lines. In particular I am interested in the distortion and harmonics graph. I searched online without finding anything, this seems strange to me, perhaps I have not looked in the right places. What do you think?, are there people in this forum who want to share their data?. Ciao and thanks.

Does anyone have a small 1-5W SET valve amp that they are not going to use? Working or not working considered.

Thank you, david

New. $160 shipped CONUS

Hello!

I recently purchased Furutech fp-126r and Furutech ft- 903r from an official supplier. Nice, but the protective cap of the fp-126r and the nut of the ft-903r, it turned out, are attracted by a neodymium magnet.
Please, someone with experience with these connectors, share if they have similar observations.

Hello!
I recently joined this club, so I should say a few words about myself. My passion is to create the best conditions for audio equipment to do its work perfectly.
Dan.y

I had the idea to combine the mid range and tweeter section of the Philharmonic BMR towers with an Eminence 15 woofer in an open baffle. Raal tweeter and BMRs would be in a MTM configuration like in the tower. I've built crossovers but always from kits or circuits that were pre-designed but never my own. I need A LOT of help figuring out what to do here? I have an inquiry out to Philharmonic Audio to see if they'll share some info with me or sell me x-overs but I've not heard back. I'm thinking I want to x-over to the Raal at around 3K hz (as specified in the Philharmonic BMRs) and a x-over to the Alpha15 at around 500-600hz. The Philharmonic towers use a 4th order Linkowitz-Riley x-over between the tweeter and the BMRs and a second order Linkowitz-Riley to the woofer. Ive heard that the x-over point on the Alpha 15 should be set much lower to get a higher actual crossover i.e. 100hz would give a x-over at 700hz for example. Not sure what I'd need to achieve a smooth transition between the Alpha 15 and the BMRs. Any help and advice (including you are in way over your head) is welcome. Thanks

I've wanted to build a bridged amplifier as a project for a while, so I decided to first simulate a schematic in LTSpice. However, I got really weird results. The first channel looks fine, but on the second, the waveform doesn’t go as low as the first channel (I’m not sure how to explain it better), and the top is heavily distorted. Also, when using the Fourier function, the first channel gets around 0.003148% THD, while the second one is around 0.4–0.5%.
Also in lt spice simulation, i used the universal op amp 5 if that matters.

Here is an image:

The green wave is the 2nd channel and the blue the first.


Heres the schematic:

I have been reading a lot of older threads, and I have run across a number of negative statements about MTM driver arrangement.

I am considering an MTM layout for a future project. It will be a pair of 5 or 6 inch drivers with a conventional dome tweeter (no waveguide), with active crossovers. For the sake of discussion, we can assume I would use LR4 crossovers at 200 Hz and 2000 Hz. I have dual 12 inch woofer cabinets.

I do my serious listening while sitting in a specific comfortable location. I do not need a big "sweet spot".

I am interested in any opinions about the inherent characteristics of the MTM layout, both positive an negative. Obviously the MTM layout has a more narrow vertical dispersion than an MT layout, but beyond that I am interested in any theories about why an MTM layout would have a characteristic sound quality.

Thanks !

I spotted some amusing videos on youtube on the audio designer Angela-Gilbert Yeung. I would like your input on the products she/he puts in the market.
Ans can someone give me an explanations for the massive amount of silicone that is randomly sprayed in the audio builds?

I want to make 5kw class D amplifier , but getting confused in output stage ,,, IGBT vs Mosfet

I want high quality audio , comparable to linear amps ,,, I am new to class D

This tutorial is designed to get you started and tweaking a decent crossover… whether you're new to crossovers, or have built speakers before and are looking for a design method that relies on listening and doesn't require measurements.

The acoustic concepts apply to an active or passive crossover, since the needs of the speakers are the same in both cases. The simple but effective example crossover included here with formulas is of the passive type. With it you will achieve a much higher quality of crossover than possible using basic online calculators, and there is enough explanation to enable you to take it to the next level. Math has been kept light.

For illustration, I will be assuming a dome tweeter and a mid sized mid/woofer but with a little common sense this tutorial can apply to more than just two-way systems using typical drivers.

• Adding a sub to existing speakers - https://www.diyaudio.com/community/...overs-without-measurement.189847/post-7378329
• Notes on 3-way speakers - https://www.diyaudio.com/community/...overs-without-measurement.189847/post-3031202

INDEX

Preparation
Post 2 - Choosing the crossover frequency - Part 1
Post 3 - Choosing the crossover frequency - Part 2
Post 4 - Directivity
Post 5 - Choosing the level
Post 6 - Baffle step diffraction
Post 7 - The design process

Design
Post 8 - Flattening the woofer's impedance
Post 9 - Flattening the tweeter's impedance
Post 10 - The woofer's crossover
Post 11 - The tweeter's crossover

Tweaking
Post 12 - Phase and diffraction
Post 13 - Tweaking the woofer
Post 14 - Tweaking the tweeter
Post 15 - Tweaking the system


You'll need to achieve these goals…
As this tutorial covers more than you may need, here is a list of the essential steps in case you don't plan on reading all of it.

1. Choose a crossover frequency based on your drivers

2. Choose the tweeter level (how loud it should be)

3. Flatten the impedances

4. Add the crossovers

…then on to tweaking. The rest of this tutorial helps in understanding how it works which will make the tweaking process more successful.

The goal of a crossover
Is to blend the sound from the two drivers (woofer and tweeter) so they work together as one. It may need to make the drivers as loud as each other, to divide the frequencies between them, and to correct or sidestep the limitations each driver will have.

Crossovers will not cut the drivers off suddenly at some frequency. There is a more gradual roll-off, somewhat like rolling a treble or bass control down. This means the drivers will be working together near the crossover frequency.

I have just dismantled my new A100 as it stopped sending sound to the speaker terminals. You have to carefully remove the side cheeks. They are just glued in and they have a glass insert as I cracked one while praising it off. You then remove the 2 screws at the flaring and the case slides off easily. Nothing much to see in terms of blown capacitors but have to test the transformer. Everything else works perfectly and did until the sound stopped. I doubt if the sound issue is anything to do with the firmware but want to try it anyway but can’t find anywhere to download it. Has anyone out there got a copy they could send me? Thanks, Paul

I am here to learn and hopefully get some guidance along the way, still a noob.

Hi All,

New to DIY audio but looking to learn how to upgrade my old marantz cd273se. Hopefully to improve the sound as I love the tda1541 chips

just a chill guy that loves audio

In this episode Brian Ding speak about how he came to develop the Rythmik Audio Servo Controlled Subwoofers and the importance of Thiele parameters.

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Hi team, not really an audio question but I know there are plenty of brains around here… I need a very simple current limiter / softstart for an 18v DC motor, just need to slow the initial turn on hit, half a second would be fine. Motor runs at around 3-4 amps but start and full load would be a lot higher. Thought about an NTC or a two position switch with a resister that could be inline for a bit then change switch position to direct (Cut out the resistor).

What do you think?

Cheers

I have a pair of Radian Neo745PB compression drivers and a pair of Ciare PR614 Horns to mount them on and I am looking to building a 2 way system to complement them and finally give them a proper home.

I am in search of a woofer to start the design process and since I am located in Italy it makes sense to limit the field to the great speakers made here. 18 sound, RCF, B&C, Ciare, would be easy to source here. Here is my active list in a google sheet which your invited to add anything that might be of interest. LINK

How to go about marching a woofer to these compression drivers? I am open to suggestions but I was envisioning a 10" or 12" woofer. How does the response curve, the efficiency, the power handling guide the woofer selection?

The setup will be BI amped with some Powersoft Q3002's and I plan on doing active crossovers with a miniDSP or a rack mounted DSP such as a EV DC-ONE

The intended use is for a mix of home stereo, portable DJ setup, band practice, and just general PA usage. The plan is to add a sub at some point.

The budget is around 160EUR for each woofer.

Volume wise I dont have a hard constraint but something in the 40-55 liters sounds reasonable.

What other requirements or constraints am I missing to nail down a driver before moving to the cabinate design fase?

Thanks