I have for sale soft start module for power amplifiers. Module was never used in practice. It could be triggered via push button or shut down in case of high temperature of case/heatsink. All temperature sensors, wires, contacts...etc. are included. Module was bought via Aliexpress, but looks the same as this:

https://www.audiophonics.fr/en/soft...ard-and-protection-for-amplifier-p-10225.html

Price is: SOLD

Hi ! i have a curiosity about this kind of drivers

i wonder what kind of advantage provides the use of those little lenses around the dome
Clearly they limit H and V dispersion But what are the benefits versus normal domes ?
Thanks a lot

For some time I would like to have an audio-transformer suitable for measurements of class-D-amps with BTL-output configuration
that will be converted from symmetric output to asymmetric scope input.
With the primary driven by low impedance amp and the secondary more or less unloaded best signal integrity may be expected.

The problem is non-linearity of the magnetic core increasing drastically with signal level and to low frequencies.
There exist special magnetic highly linear materials, but not available to me.
And available audio line-in transformers cannot handle loudspeaker levels.
They simply are too small, here it is size that matters.
So why not use one off-the-shelve toroid mains-transformer -
connecting the primary 230V winding to the amp
and the secondary to the scope.

In my stash I discovered an 48VA toroid with 24V secondary, giving close to 10:1 or 20dB attenuation.
I think there is nothing special with this, so similar transformers might yield similar results.
For the test I fed the primary with my MOSFET-Class-AB-Mono-Block, driven by the MOTU M4 soundcard.
The secondary was connected with the input of the soundcard.
Sample frequnency was set to 192kHz.
Here is the summary of THD measurement at various levels and frequencies.
All in all this is much better than I expected after disappointing measurements of audio line and mic transformers.

Hello, I have a friend who have a a pair of the original ATC SCM12 model. It performs really good for its age, but it is a speaker on the "dark side".

The tweeter it uses is the Vifa D26NC-15-06 which is supposed to be flat and with a little spark in the 16khz area, so we don't understand why its dark sound.

I want to ask if it is possible to make some kind of mod in the crossover to make them a little bit brighter. Here are the pics he has sent me of the crossover. Thanks in advance for any help 🙂

Attached is an American-German developed 2" mid-dome driver found in the ADS and Braun speakers. The unit in the photos was taken from ADS L980/2 speakers. As can be seen, the magnet is covered by a large metal cup on the back, blue arrow. I've acknowledged that the cup was installed there for forming a chamber or a closed enclosure to lowering the Fs of the unit.

In the L980/2, the high-pass crossover for that mid-dome is published at 450Hz. In addition, its bigger brother which utilizes the same midrange unit, the L1590/2 speakers, is published at 350Hz. While the smaller brother, the L880/2, is published at 550Hz, but it has no metal cup installed on the back of the magnet, as their bigger brothers, for lowering the Fs.

What's the trade-off of lowering the Fs, between having and not having the rear chamber on the back of the magnet? This question also applies to the large surround usage, in the picture of the front of the dome.

I’ve got two power amplifiers for the candidates: a 5-channel Soundstream Reference 405 and a 2-channel Nakamichi PA-302. I’m going to employ both of them to my speaker sets.

Here is the list of my speaker system:
Front speakers: 4” Boston Acoustics CX-4
Rear speakers: 5 1/4” Boston Acoustics Pro 5.0
Subwoofers: 10” MB Quart QM250 SUB

Definitely, the MBQ subs will be driven by the SS amplifier, as the SS is 3/5-channel and provides a subwoofer channel.

I have two options for the combination of the speakers and amplifiers:

Option A)
Front: Nak + CX-4
Rear: SS 405 + BA 5.0

Option B)
Front: SS 405 + CX-4
Rear: Nak + BA 5.0

It seems to be an easy question for somebody but there’s a little complexity, for me, there.

The CX-4 is labeled power capability of 20W nominal and 40W peak. While the Nak is rated power output at 80Wpc and the SS is rated at 40Wpc in 3-channel mode (bridge). All values are based on 4 Ohms impedance car audio standard.

So, I’m not sure if option A, using the CX-4 with two times power amplifier (the Nak), would harm them or not. And, for option B, the SS has lower power but in practice it’s recommended to set the gain of the front amplifier higher than the rear amplifier, thus, the front amplifier should have more power than that of the rear.

Which option do you prefer?

Hi All,

Just wondering, is it a good idea to use a single ended amplifier for headphones, given that the phone impedance vary over a very wide range? I have come up with a circuit as attached, and wonder whether it will work as an output stage of a headphone amplifier? Appreciate any comments, on whether it will work, or any changes that will make it work. Thanks!

Hello,

I can't seem to solve this problem:
Technics amplifier SA 150.
Using Aux in via a cable (RCA/3.5mm stereo) from my laptop
Laptop has mains power supply, no earth.

I get a severe computer like random noise.

Quiet when disconnected on the amp side.
Noise goes away when I run a short wire from the amplifier antenna shield ground to one of the RCA input grounds. - Solved and almost usable.

However, I now have some mains hum which goes up and down with the volume so it is from the input.
It stops when I disconnect the cable on the laptop side.


It does not stop when I disconnect the laptop power supply (run on battery).

I previously used my Marantz SR340 amp for this purpose with identical setup and there was NO computer noise and NO mains hum.
All this has been introduced by swapping amplifiers.

How can I troubleshoot and fix this this?

Best regards
Bernt

As a relative newb to DIY audio, but having a solid ability to solder and follow directions, though lacking understanding of theory, I see all these amplifier builds, but nowhere near as many preamplifiers to control volume and/or tone? What would be a good beginner level preamp kit or build for someone who already has a nice class A amp? I am finding out that "front end" "line stage" "preamp" and more can all mean the same thing as far as control goes, so it can be very confusing for the beginner. If needed, the amp I'm trying to control is a Pass Aleph 30. I have a phono preamp already, so just a stereo preamp is what's needed. Class A preferred. I've been going cross-eyed trying to figure this section out. Any help from the gurus is appreciated.

Cheers!

I have recently develop this PCB it is used to make unbalanced audio signal in to balanced, this allows
to use amplifiers in bridge output configuration "mono".I have here this module mostly for the PA150
amplifier boards "LM3886" but it can be used for other audio amp modules, it is operated with +15 and-15
Volts.Pictures with assembled parts as an example.
If you enjoy this kind of stuff you could check here:
https://www.ebay.de/usr/dialedinmusic?_trksid=p4429486.m3561.l2559

Hey guys. So I plan on doing another 3D Printed speaker but this time, as the title suggest. I will be doing 2.1(or 2) setup. 2 reasons for why I want to do isobaric. I want to keep the box small (using the 2 4" daytons will increase the box size which I don't want to do - I want to keep the speaker handy or the ability to be carried and put almost anywhere that I want.) and 2nd is that I want more bass from a 4" daytons nd105. So can anybody give me tips on how I can utilize everything properly. Suggested box size, thickness of the 3d printed housing (I used 5.2mm on my first build) passive radiator size or literally building tips of the whole system since I am fairly new to this DIY audio.

Parts:
Aiyima 2" 20w full range
Dayton ND105
DSP 2.1 from aliexpress (good reviews tho)
21700 batteries with BMS

Goal:
-Keep it fairly "small"
-With passive radiator so that it is less sensitive on placement in the room
-Harman Kardon sound quality(?)
-won't cost an arm and leg to build. ($200 max)

I think that is it? Please feel free to educate me. I am here to learn. Thank you so much!

Attached is the output stage of a preamp board I'm building and what I measured for the amplifier input stage(don't have schematic). Am I correct to conclude the voltage divider and coupling cap on the output is redundant and can be eliminated?
I'm still populating the preamp so it's easy enough to leave out. I'd like to keep the signal path as simple as possible.

Just picked up a pair of large drivers at a garage sale, Radio Shack 40-1315 15” drivers. For 10 euros, not a huge risk.

Can’t find much info apart from that they would be 8 Ohms (DC resistance is indeed 5.9 Ohms), 100W and go from 35 Hz to 12 KHz. If all that is true.

Is there somewhere a RS catalogue (scanned at sufficient resolution to be legible) describing these?

They would be a musical instrument speaker, like for a guitar amp or for an electronic organ.

Have yet to attempt a listening test (open baffle 1.70 x 1.20 m).

Thanks for any info or pointers!

Just wanted to say hi!
I bumped into this forum multiple times and I alway got useful informations.
I got into building speakers lately and I want to do creative designs for DJs. So I decided to register and ask you some valuable questions

have a good day

ale

Eu estou gostando do fórum, estou lendo no tópico https://www.diyaudio.com/community/threads/ebay-amp-is-500w-believable.309168/page-5
e gostaria de postar uma resposta.

Saw this tiny 500W amp board on Ebay.
IRS2092S 500W Mono Channel Digital Amplifier Class D HIFI Power Amp Board J3K7 191466622261 | eBay
Are the figures for this general type of amp even believable, or are they a total exaggeration? Thinking of using a pair to drive a pair of 15" subs in relatively small sealed boxes with a Linkwitz transform equaliser. Not to a very high sound level but I expect the overall efficiency will be down the toilet. Also thinking of experimenting with 3 boards as a low voltage 3-phase AC source for driving a motor. Just for fiddling around, nothing practical.

So... is this kind of board worth the trouble?

Edit -> updated broken link

For Hifi helper woofer to compliment either a fullrange or coax…..is there really such low HD as claimed?

Second installment of Plethora of Pinjatas series of amps

Started with this

I'm looking for the full range and tube amplifier.

Guys,

I used to buy fuses at Radio Schack but it closes now.
Does anyone know where to buy fuses in Southern Cal, Orange county?
Thanks.

I believe this was drawn up in some sort of CAD program and whoever did the drawing saw the right shape on screen but didn't check the orientation.
I've done this sort of thing many times in my own board designs, but it's not something I'd have thought would get through QC at a company as big as TE Connectivity and I'd also have thought that somebody before me would have said something to Digikey.
So, I might well be wrong, which is why I'm asking you to take a look and say if you see anything amiss.
Thanks

Anyone ever own or hear the Eminent Tech LFT-8B speakers? I had them for many years and I think that they're still pretty unique. A dipole with ultra-thin mylar sheets, etched with metal lines, through which the current from the amp radiates, and an 8" sealed woofer. Remarkable clarity and window into the recording. However, very sensitive to the room and difficult to position for full effect. I ended up replacing them.

EDIT: The problems encountered initially have been solved in this thread by numerous tests and with the assistance of jpk73 and mdardeniz as well as the contribution of element of the work of JeffYoung. I give files here and i will see to establish component list.

Hello everyone, three years ago I built two NAP 250 clones from naim, these were my first DIY projects and even if they already give (very) good results, I still made some errors so I wanted to launch myself into a new, more successful version, so I reworked all this on the net and on this forum as well.

I redid all the diagrams in Kicad directly in order to improve the design of the PCBs and their skillscreen printing by sticking as closely as possible to the original NAIM
I placed output transistors on the PCBs and not wired in the air which improves stability and construction
I changed my PCBs to double-sided 70 microns instead of double-sided 35 microns like on the old versions
I note as my work progresses all the verified information in my diagram
I went through plenty of pictures of the original Naims to determine the correct values and was able to correctly determine and identify three versions of the phase correctors to the driver transistors as well.
I determined the values of the phase compensation resistors according to the output transistors used.
I was able to correct an error on a value of a capacitor, on the input filter it is a 470pF and not a 330pF.
I changed the output capacitors on the regulation card for "high" ESR capacities >1.7ohms which corrects an oscillation problem.
I was able to determine that without the protection circuit on the amplification board the sound is not particularly improved and that the offset is much longer to go down when switched off


this time I use the original drivers (MJE243/253) on the regulation cards and not those recommended by Neil mcbride which greatly improves performance and stability
I then searched for better substitutes for the unavailable transistors by closely studying many datasheets namely the VBE (ZTX384 or ZTX108) and the output ones, the Mj15003 not being the best.

I thus tested with the oscilloscope and by ear for the VBE the 2N2222A in comparison with the 2n5551, my choice fell on the 2N2222A which seems to me a little better to the ear but also on the noise in the data sheet. I also tested the ZTX690B and 2N6428 it's works but it's not better.

For the output ones I tested:
BUV22 but they are not really suitable for the ear it is not very convincing and I think that the bias and the drivers are not suitable, there is too much crossover distorsion with MJ243/253 drivers.
Mj15024 they seem better to the ear than the Mj15003 but they are only 15A so there is no point in taking T0-3 boxes, there are also too much crossover distorsion with Mj243/253
2N6341 They are suitable and sound better to the ear making 40mhz for 25 amps they are probably the best performing so I have chosen it for my new amplifier.

I had noticed Phase compensation problem with 2N6341, I didn't initially understand the problem, I was able to fix it as you can see later in the topic.

The adjustment of the phase compensation is more or less delicate it depends on each type of power transistor used but it also depends on the PCB layout. If the MJ15003 and the BUV22 are quite easy to adjust, the same is not true of the Mj15024 and especially the 2N6341. Having done the setting for the PCB layout used in my amplifier (V2.1) I cannot give the optimal values for the latest files I give here (V2.5)

I give the correct values for version 2.1 so that you can directly use these PCBs if you want to build the same amplifier without having to do the adjustment. For those who would like to use the latest more advanced version, you will have to make the adjustment yourself. The rest of the topic will show you how to do it.

For the components I chose the original MPSA06/56 from diotec and not those from central component as for my old creations, indeed central component makes copies and not originals, something that I did not know.
For capacitors I chose for the amplification card very high voltage WIMA and also for the miller. (on my old version I took 39pf in Mica, there I took 33pF and 47pF)
i take organic polymer low esr for the AMP BOARD
For the NAPS Board please note output capacitors 10Uf must have a esr >1,7 ohms for stability of the supply.
For filtering I chose a very high quality EPCOS 22000uF 100V capacitor 4 milliohms of ESR, 57 amps of rejection capacity in place of the previous Mundorf 22000uF 80V (7 milliohms 33Amps)
All my components are ordered on Mouser by preferentially choosing the manufacturers

For the resistors I chose to switch to 1W or 2W in metal layer in order to further reduce the noise against 0.5W on my previous realizations
only the 0.22 ohms on the output is wound due to lack of availability.
For the plugs I chose larger plugs more suitable for 2.5mm wiring and above all offering better contact and better manufacturing quality.

For the pairing of the transistors I invested in a second-hand RIGOL DG1022Z BF generator which allowed me with my oscilloscope in XY mode to draw the characteristic networks of the transistors which I had not done during my previous achievements, I had simply used the HFE.
I ordered series of transistors and as I had other of my previous orders I was able to operate pairings on:
BC550C in LTP are matched
VAS ZTX653/753 are matched
MPSA06/56 on the protection circuit are matched
MJE243/253 in drivers are matched
2n6341 output are matched

On the regulation boards I used identical paired MPSA06 series and also paired MPSA56 series
MJE243/253 drivers and 2n6341 output drivers are also paired
capacitors are MKP higth voltage general purpose
resistors are 1W-2W metal too

For the variable resistors I take multi-turns unlike my previous amplifiers, in fact the single-turns are not precise enough and can move with time and vibrations.

The transformer is a high quality encapsulated nuvotem talema 500VA to reduce vibration and ground buzz

The 4 cards are mounted, I still have the last heatsink to manufacture, I am waiting for my aluminum case and the last parts in order to start the final assembly, I expect to receive the case in less than 15 days.

to note unfortunately on my PCBs I made a footprint error on the 39pF capacitors which were far too big, I was deceived by a bug in the Mouser search system which was giving me 4uF capacitors instead of 40pF.. .
I have since corrected the error in a new version of my PCBs in Kicad but my PCBs being already ordered I use those with this footprint error.


Here a caracteristics of a transistors i use two différent resistor for the base 100K and a 3300ohms for testing different currents


Here you can see phase compensation problem

First regulator board, note larges Capacitors are organic polymers low esr and not electrolytics. C105/205 later changed by united chemicon electrolytic with 1,8 ohms ESR
On the first amp board there are not the circuit protection i want to test with ears with and without the circuit protection when the amplifier will be finish.
here on a 2Ohms resistor
here the test of stability on the regulator down it's a power rail of the regulator board it's about 100-150 mv variation on a square wave 1000Hz 100mV in the amp
47pF are on the other side...

a heatsink with his isolate board to isolate from the PCB

Here V2.1 correct values for phase compensation are:
R26 1800 ohms
R27 1800 ohms
R29 2000 ohms
R30 2200 ohms
(note for the drilling of the heatsinks that the two output transistors are not perfectly aligned either on the AMP BOARD or the NAPS BOARD)


Here the last files of schematics and Kicad PCB V2.5 (V2.4 For regulation NAPS board), This version is better the holes are aligned for the T0-3 but the values for the phase compensation must be developed:

Hello everyone Tell me, is it possible to tell from the photo whether it is the original or a fake? And where can I see the decryption of the production date code?

Hi all,
I feel this should be basic knowledge, maybe I am using the wrong search terms or phrases, but spent 2 evenings (several hours) searching how to do this and came up blank

I am looking at building my first amplifier - I am looking at a class AB board from AliExpress which needs a 30v-0v-30v AC input.
I found what I thought was a suitable AC transformer but would like to ask How do i wire the 4 wires of the transformer to the board?
It has 230v input and 2 x 30v output AC?
Would anyone have a sketch or drawing showing how to connect?
I cant save individual images from the listing to show but here are the links to the items I am looking to purchase. photos in description

https://www.aliexpress.com/item/330...=scene:pcDetailTopMoreOtherSeller|query_from:

This is the toroidal transformer i was going to use

https://www.aliexpress.com/item/100...3LUQVq7c&utparam-url=scene:search|query_from:

Does anyone know spesifications on the audio note morite ref. Nr 8029.

Second question is: can it be used in the dddac 1794?

No-1
No-2

Over the years many tube circuits caught my eye and challenged my ability to understand and sure enough I came to understand how Triodes worked but not Pentodes.

So taking my knowledge of modern electronics, Jfets, Mosfets, Transistors, IC's etc. I decided to think about Triodes and what property does a Triode have that no other modern devices have. One thing stood out - the Grid, Grid resistance can be very high when negatively biased relative to the Cathode, also its capacitance can be very low typically 1-2pF (this remains true if gain is kept low). OK so you say that a Jfet can do this but a Triode Grid can be very robust as regards large over voltages and typically if a Triode fails it goes open circuit whereas a Jfet can easily go short circuit.

Now I was thinking that it would be interesting to build a Triode front end with very high Grid resistance and low gain (say about x3) to keep the Miller effect down. With a Grid capacitance of say 1.5pF I could be looking at no more than about 6pF effective Grid input capacitance. I bought some GE (or Chinese copy) JAN 5670W tubes these have much the same specifications as 5670 2C51 6385 396A etc. This is a small Dual Triode that can dissipate (Anode dissipation) about 1.35Watts per Triode maximum. Here is a graph of its Anode voltage vs current for different grid voltages:

Next question is bias, where do I want the DC bias point to be on this graph? After some thought I came up with the following thinking:

• DC bias dissipation must be lower than the tube's maximum so about 1 Watt seemed OK
• DC bias dissipation should not be too low (small currents increase noise)
• The DC bias sweet spot needed to be in a place that looked most linear (Grid voltage curves evenly spaced and as straight as they get)
• The DC bias sweet spot should be nowhere near positive Grid voltages (relative to the Cathode)

Hence the "sweet spot" at Anode current of 8mA and Anode voltage of 130 Volts (a DC bias dissipation in the tube of about 1 Watt).

Having tested my JAN 5670W Dual Triodes (and I had bought a lot of them) I knew that for a fixed Anode current and Anode voltage the Grid voltage varied quite a lot around that -1 Volt to -2 Volt range. So then came the "eureka" moment, I realised that I needed a circuit that did the following:-

• Kept the DC bias current flowing from Anode to Cathode at always 8mA (the final circuit was about 8.15mA)
• Kept the DC bias Anode voltage at always 130 Volts
• Allowed the DC bias Grid to Cathode voltage to vary quite a lot to keep the above true
• Set the Gain to x3 and give me plenty of negative feedback local to the Triode to reduce distortion and keep Miller effect Grid capacitance low

Another "eureka" moment and I realised that I was throwing away all the Triode front end preamp circuitry I had ever seen over many many years - never to touch it or go near it again because it never set both DC bias current and DC bias Anode voltage and made them both fixed and constant. So now I had a circuit that was very tolerant of quite large specification differences between Triodes and even between different types of Triodes. Here is the circuit in its simplest form:

The 6K Anode load resistor used has a constant current flowing through it so it fixes the Anode bias voltage. It does this by Ohms law - voltage across the 6K Anode resistor is 8mA x 6K that's 48 volts. So the Anode voltage stays at the HT supply voltage of 180 Volts minus the 48 volts which is 132 Volts. So you have a fixed Anode to Cathode current because of the 8mA current sink and a fixed Anode DC bias voltage. The advantage of this is fixing two axes of the characteristic curves for this Triode at the good place (the sweet spot). Obviously for AC signals then of course the current from Anode to Cathode and the Anode voltage are varying around the DC bias values.

Ltspice scheme or normal scheme Which one is good?

I am trying to repair several Sonos Connects which have no analog output. I have already repaired the power supply boards, which were working ok but had higher ripple due to failed electrolytics. I have drawn the analog board circuit, and have traced the issue down to the mute circuit which I have posted below. I have modeled the circuit in LTSpice and have found that it is not operating properly. Can anyone help describe what exactly this circuit is trying to accomplish? I am especially confused by the 2.2uF tied to 12V on the right side. There is voltage present at the negative terminal of that capacitor. Even removing the 680K, there is still a few volts present there. I am also seeing around 15.2V after the leftmost BAT54. Removing the 10uF capacitor reduces this and causes Q1 to operate as I expected, but I am not sure what is causing this.

Fully built and tested. Clearing out some unused gear. $200 USD

My publishers inform me that the 2nd edition of Small Signal Audio Design has reached the practicable limits for the size of a book. (It is 750 pages long) Perhaps it is as well not to write a book you can't pick up with one hand.

I therefore propose to split off all the material in SSAD2 on phono amplifiers and vinyl replay generally, add a bunch of new stuff which I have thought up since, and make it into a separate book.

This is some way down the line (next year at earliest) but I would be very glad to hear opinions on what the book should contain, especially stuff not currently in SSAD2.

Hi!

I have an LS1 with a shorted power transformer winding. Does anyone know what the specs on these for a replacement ?
From the schematic I do have rectified voltages : 415 for HV and 22.7V before regulation for filaments. That would equate to somewhere around 295VAC and 17VAC windings but I would love confirmation.

RB-TK2150 diy hiend class T amplifier for sale 67€
Genuine Tripath evaluation pcb board with TK-2150 chipset applied,with all active components and heatsinks also the correct inductor cores are supplied.
Tracked shipment to European union
Skematics sended together with articles.
Payment by PP
If you enjoy this kind of stuff check my stuff related:
https://www.ebay.de/usr/dialedinmusic?_trksid=p4429486.m3561.l2559

I have this sample pack of WBT connectors and I am looking to mate 2 of them up and sell or trade the rest. These buggers are $67each!!! And before I go and spend $134 plus tax and shipping for a pair to match what I have, I thought to see if anyone else has some laying around in their stash I could buy or trade for??? Anyone???

I have red/black 785
Red/black/gold 765
And a white/gold 745

HI
I am a freelancer offering 2d Animated video Services. I am facing a problem in one project where I have to edit audio of clip. I did some research and found that I will have to use Audacity for this project.

Now I am trying to install it in my pc and it is showing memory error on installation. Does anyone in this group has experience with Audacity Software

Hello can anybody help with schematic for this amp ? I have C2016,C2017 blown and not sure what size mylar capacitor is needed. Also L2000 is burnt If anybody can point me in the right direction for schematics and also where to purchase parts that would be awesome.

Hi,

I am wanting to do a 2 way build with beryllium compression driver (if I can find a 4" else 3" diaphragm)

Any thoughts on the purifi PTT10.0X04-NAB-01 (or even 2 of these) vs the 18sound 15NTLW3500

Hi, I´m from Santiago, Chile

X-Altra Mini II Preamp, fully built with Goldpoint Volume Pot. $800 USD

New input transformer, higher than usual output voltage level - check the peak to peak voltage in the 10kHz square graph, 100Ω source, 200k load, no Zobel network whatsoever. In the 10Hz-200kHz sweep graph, level response x2, x4, x6 for the x1 input (green)
Compared with triode 26 (in photo) I think it does about the same thing but with way lower distortion 🙂 - still, not comparing apples with oranges...

Hello everyone, I'm from New Zealand. Glad to meet everyone here. I'm a software engineer who is interested in electronics especially audio products. Please help me as I'm a newbie especially in analog electronics.

I have wanted to build a high efficiency speaker for a long time but something else has always seemed to jump the queue. camplo's 2 way thread and some of the ideas there inspired me to buy a pair of Faital HF146R drivers. I plan to use Faital 15PR400 woofers but I haven't bought these as yet. I found mabat's Ath waveguide tool at the same time and since then I have been trying various different waveguide designs and simulating them with ABEC. mabat's tool makes that very simple in an infinite baffle. To go further and turn that into a free space simulation in an enclosure is a bit more complicated.

I found a design which seems promising and have begun simulating this in an enclosure with various edge treatments to see the effect of those.

The waveguide is difficult to render and show the contour but the attached images should give some idea.

I'll post some more details and images of the simulations to show the sort of output you can get from ABEC. I enlisted the help of DonVK to help me get my head around how to drive it and it is now starting to make some sense.

Although at the moment this project is still quite virtual I do intend to build it in the real world. To that end I have bought a CNC kit which I am in the process of building up. Hopefully it will work well enough to allow me to mill the the majority of the cabinet by CNC.

UPDATE: 02-June-2024: This group buy is now closed.

After the second Omicron group buy closed in September last year, there has been a number of requests for more boards, so here is another chance to get them. Building Omicron may be a nice summer project! 😉 This GB will close at the and of the day on Sunday, June 2, 2024. If you're interested, be sure to sign up before then.

The following four boards (bare, unpopulated, parts not included) are offered in this GB, in any combination:

• Omicron through-hole PCB: a 80x110mm, two-sided board that carries two amplification channels, optional crossfeed, DC protection circuit, and the output filter. All parts are through-hole and regular sized, so the board is easy to build. The output stage is heatsinked, so the amp can be run at higher quiescent current if needed.
• Omicron SMT PCB: a 60x90mm, two-sided board that carries two amplification channels, relay-switchable crossfeed, DC protection circuit, and two output filters (one for headphones, one for line output). The board itself serves as a heatsink for the output stages. Most parts are SMT, but with no parts smaller than 1206 or SOT-23, this board is reasonably easy to solder by hand.
• Omicron power supply PCB: a 130x80mm, two sided PCB that carries an AC mains filter, 230/115VAC mains voltage selector, a power transformer, a pair of regulators, and an quick-turn-off circuit that works together with Omicron's DC protection. This board is optional - you can power Omicron from other suitable power supplies - but it has been tested in multiple builds to work well with the Omicron.
• Omicron DC protection PCB: a 50x50mm, two sided PCB that carries a copy of Omicron's DC protection. This board is not needed to build the Omicron, which already includes the same DC protection circuit, but may be used with other headamps. The quick-turn-off of this protection works together with Omicron's power supply board.

What it is

• Omicron is a compact, inexpensive and easy to build headphone amplifier with uniquely low distortion, very musical, pure, clean, liquid sound and perfect clarity even in the most harmonically complex pieces. As one of the first GB participants put it, "The clarity is surreal."
• Designed to work with 32 to 600 ohm headphones and tested with a range of over-the-ear and on-the-ear cans from AKG, Beyerdynamic, Grado, Klipsch, and Sennheiser as well as with lower impedance 16 and 8 ohm headphones, such as AKG's K3003 3-way in-ear monitors; even white Apple EarPods (tethered ones, both 1st and 2nd generation) sound great with Omicron, too!

Features and benefits

• Ultra low distortion; at -140dBc, Omicron is an order or two more linear than other "high-performance" and "ultra-high performance" headamps. Omicron adds neither dirt nor fairy dust, offering exceptional clarity and fluidity of sound. With Omicron and a good pair of cans, music just carries you away. And if you want to look at the measurements, we have them, too.
• Simple and inexpensive to build. One channel of Omicron is built with just one dual opamp, two transistors, ans a bunch of resistors and capacitors. The circuit allows broad opamp substitution and has been tested to work well with many modern (e.g. OPA1642) and not-so-modern (NE5532) opamps. At the time of the first GB, the total cost of parts to build one Omicron board (two channels) was just $42.
• Built-in fast (10ms) and sensitive (80mV DC) headphone protection.
• Built-in optional cross-feed circuit, helping to create a more realistic soundstage.
• Compact and easy to build.

Pricing

• $5 per one protection board, $15 per any other one board, plus shipping.
• Shipping is calculated at checkout. U.S. Postal Service offers inexpensive shipping to the continental U.S. starting at $3.80 (USPS Ground Advantage) with tracking or $1.60 (USPS First Class Mail) without. International shipping (USPS First Class International Package) will cost somewhere between $16 and $20, depending on the destination. Should you want to buy something else from me, I of course can combine shipping.

Technical details

• The main thread has lots of details, including full schematics, part lists, board outlines, assembly instructions, and more. The first post in the main thread includes a list if links to most useful posts. I will review the thread in the coming days and update it as needed.
• The DC protection has its own thread.
• Part lists aka BOMs has been published for each board. I will update the BOMs over the next couple of weeks making sure all parts are available and any errors and omissions discovered so far are corrected.
• We support Omicron builders in the main thread.

If interested in purchasing any of these boards, please reply to this thread. Copy this sentence along with everything below into your post and add your own line as follows:

(1) Your name here on diyAudio -- (2) TH board, pieces -- (3) SMT bare board, pieces -- (4) PSU board, pieces -- (5) DC protection boards, pieces, -- (6) Country to ship the board(s).

Try to preserve formatting.

Running List for Subscription:

drof -- 1 -- 1 -- 1 -- 0 -- Poland
Brakspear75 -- 1 -- 0 -- 1 -- 0 -- UK


This group buy will close on Sunday, June 2, 2024. Be sure to sign up before then.

I had originally intended to just make a few small (EQ'd) sealed subwoofers; I like their sound-quality, size and simplicity. However I'd also like multiple (at least three) distributed ones for reasons of room-mode smoothing and room flexibility. In that case the subs may not be near the main speakers, so being able to 'localise' them would be unfortunate.

I'm convinced that most people can't localise sources below 80hz (certainly not below 60hz), especially if the sources are from multiple places simultaneously. But if the subwoofers output extraneous higher frequency noises (harmonics, resonances etc), then that could easily destroy the illusion. So I'm now considering 4th-order bandpass types of enclosure, because an acoustic low-pass filter will catch more sources/causes of higher frequencies than an upstream electronic filter. Though an acoustic band-pass is much more difficult to achieve, especially without degrading the audio quality itself. So this is all a bit tentative, and I shall reserve judgement on whether to go with bandpass or sealed for the final versions.

The drivers are like the venerable LAB12, which many people will be familiar with. My actual ones are from BK electronics here, named the FAB12; a small upgrade in specs but essentially interchangeable. They would have been ideal in small sealed boxes but I think they might also work in bandpass configurations. I'd forgotten how finnicky and buggy WinISD is (to be fair, it never got past beta, but I'm only just starting to find my way with Hornresp at the moment). However, with some persuasion WinISD has suggested this is possible:

A frequency response between 25hz and 80hz (-3db) up to 109dB at 1m (peaks) within Xmax - achieved from 320watts and 63L total internal volume. A 10cm diameter by 39cm long vent would reach about 27m/s air velocity, which is not ideal but (I gather) still within what many people seem to find acceptable for subs -assuming rounded vent ends.

There is a lot of talk around the internet of bandpass being slow and muddy, allegedly due to the vent output affecting timing in various ways. That is a concern, but the group-delay actually doesn't look too bad in winisd, at least. Here it is shown (for comparison) against a sealed box with typical high and low pass electronic filters instead of acoustic bandpass types; by comparison the bandpass is less smooth but I'm pleased to see that it isn't massively high at any point:

(the bandpass still needs a subsonic high-pass filter, according to winisd, hence one was added for the sim. Most sources/amps roll off by then anyway, but IMO better safe than sorry).

So i wonder if the poor reputation of the bandpass is due to also poor implementations. It is 'much' more affected by quite small deviations, which is no less of a concern to me, but one which could in theory be overcome. I guess the drivers would need to be well run in and the boxes tuned via actual measurements, rather than just applying generic driver specifications and winisd simulations.

Anyway, I had feared the bandpass box would need to be massive, but actually those sizes and SPLs seem reasonable. As I'm intending to go with distributed subs there will be at least three, so would total nearly 114dB at 1m, or 105dB at 3m/10' (before any remaining room modes muck things up). In practice I'd likely attenuate one or more of the subs for balancing, but also in practice some may be nearer than 3m/10'. So that still seems plenty for music (and occasional films) in quite modestly sized rooms, unless I'm being naïve.

So.... these were my initial thoughts and reasoning; if anyone spots flaws or disagrees I'd be very interested to know. This will be a slow project - time is limited and access to workshop facilities very rare. I'm also intending to pair these subs with another parallel and more complicated build; multiple entry horns. However, I have the drivers and so will hopefully be spending/wasting time on some kind of prototypes reasonably soon.

Cheers
Kev

If you have unused parts to populate Clave Fremen MyRef boards, I’d like to buy them.

hi,
my ML 38s preamp damage by wrong voltage, i check it the line part is good, problem is on logic control, the logic have three programable ic, if once damage must cant power on, one is cpu(mc68hc11a) one is eprom 27c512, one is peel18cv8, the problem is on peel18cv8 because its very hot, and cannot read data use my universal programmer, 27c512 is ok and have read the data, the cpu i check ref voltage also is ok
now i have new peel18cv8 but have not the inside data, please help me where can get the data, i have ML 332 also use peel18cv8 to logic control, i use 332 18cv8 in 38s, the panel have respond but not proper work, i think 18cv8 is differ version because the label code is differ
please mail me if someone have 38 or 380 18cv8 data code, i can share 38s eprom data and 332 18cv8 data,
thank you vey much
steven

Does anyone have an extra module they'd like to sell?
I have a Marants HD amp1 from a friend that uses this module and that needs to be replaced.
Unfortunately, the unit is not available to hobbyists from hypex.
PM plz

Hello.

Fifty something music lover here in the UK.

Not a major 'tinkerer' nor constructor but I like good sounding audio.

I enjoy building streamers; both Raspberry Pi (current favourite using moode after years of RuneAudio but not keen on Volumio) and recently I've moved to an Intel NUC (using Daphile which I think is an incredible system). I'm sure I have a Chromecast Audio somewhere too.

Playback is through the very under-appreciated Tangent AmpsterII and JBL Control 1s and old sub but soon to change to Tangent Spectrum X4s and Tangent AS-160 sub which all suits my budget and small listening space.

Music choices range far and wide, some classical, some ambient, 50s through to modern but not too current (it all sounds the same) or too Heavy Metal (I like my eardrums unscathed!). Also enjoy good online radio stations too.

So, that's me.

This project has taken a different turn with an impulse purchase ZR12.4D driver not doing too well in sims for sheer output. Now the floor is open for a replacement choice, and in the meantime I need to get at least one cab up and running by August. I have been sitting on a 10" driver for a couple of years as stocks of those ran out, and I couldn't get three more. It's never returned to stock since. I'll use it now to get one working cab and then source 4 drivers that can do this role

The job is spending most of the time as HT and music on an open boat deck 3x6m and part-time as practice PA for some aspiring young students to plug their school instruments including electric bass/double bass and the acoustic instruments wearing synth pickups to mess with school material in form of the systems regular use music with a couple of examples given below. They will be plugging into my Roland Pro gear including digital mixers and synths from the Aira range as well as Akai pro gear

Normal use will be tube for the tops and tube flavoured class d for the dubwoofers and all tube flavoured class d for the girls pro use

The urgentish need is to have something three of the girls can plug in for lil demo in August of what they're doing, but the school PA has no low bass

So space is dire short, transport difficult and sizes must be kept as small as possible but the output needs to be clean and solid. Pls see the two examples of the usual listening material

Login to view embedded media Login to view embedded media
Let's see if the Bagheera Sound System can ever be born (name is a pun on the boat, which is a cat, amongst other great cat fetishes)

Driver chosen for the point source efficient tops are the PRO-ZT69. The system will be a speaker in each corner with a phantom centre

This is the unobtanium 10" in 20L and Fb 43Hz against my recently compiled virtual references for subs out of small boxes in WinISD and the top, with all at full power. There is over-comprehensive DSP tuning available in the Roland MX-1 digital mixer which will be the brains of the system as well as a DJ-202 for one of the girls to learn to perform on. Not the MX-1 though. I was lucky to score the last new one in Au and no one is touching this most unusual kind of device packing King Tubby into 18in/18out digital channels 😀

The master active speaker will also hold a DSP board featuring HT in the form of AC3 and DTS with full i/O

The blue traces are the 10" and the PRO-ZT69 both at full power. This is what I have to work with for the moment and to pick 4 new drivers for the sub array for the system

Hi all,
Putting together a feasibility to build the Helios tx project.
Can anyone enlighten me on the part specs for the crossovers, in particular the resistors? Wondering if they are 3k, 12k,5k,3.9k ?

Thanks, David

I have a M-Audio Firewire 410 Digital Audio Interface that I'd like to give away. The unit works and comes with the power supply, cable and original box. If you're near San Jose, CA you can pick up the unit. If not, we can arraign shipping. It shouldn't be expensive to ship it only weighs 5lbs.

I figure nothing ventured nothing gained right?

For a current project I'm working on I would like to use a carbon fiber shell. Google doesn't have any good news for me in terms of price so I figured I would ask the community lol.

Hello, I purchased a used B&K ref 200.5 and letting it run for a few hours with nothing hooked up it's really warm to the touch. I measured heatsinks at around 150 degrees but I have heard they do run really hot just idling. I tested DC offset on all 5 channels and channel 1 and 2 are between 6-7.mv's, the other 3 channels are around +-1mv. I'm going to adjust Bias and DC offset and wondering if Bias setting is 200ma across the fuse holders like most B&K mosfet amp's? I haven't been able to find a service manual for this unit yet. If anybody has one I would be greatful!
Thanks

Best CD player Cambridge ever made. Upsampling with Swiss-software, Anagram Technologies, to 32-bit Blackfin DSP chip at 384kHz/24-bit. Full dual differential twin Analog Devices AD1955 DACs with 3 filter modes. Heavy-duty disc drive. Can act as DAC--accepts digital inputs. Absolute Sound review from 2013, https://www.theabsolutesound.com/articles/cambridge-audio-azur-851c-cd-playerdac/. Original owner, bought new in 2014. In great condition, sounds wonderful, not a scratch, only caveat is that the on/off and eject push buttons on the front panel and the remote are a bit finicky. Often takes two or three presses before engaging, though play and forward/reverse ok. Asking $600 + shipping.

Hi, I'm an enthusiast looking to build a nice tube amp, I'm just tired of the sharp electronic amplification. I have a ton of used vac tubes I'm sorting through, alas most of them will go in the bin as they're mostly TV tubes. It's been about 45 years since my single semester EE class in tube design so the cobwebs are deep....

ram 100 mk2 port length needed please - after an experiment i realised my cardboard ports were lost - i got some more but need an owner to slip a tape measure in there

In your experience, which of the following toroidals have been consistently of better quality, regulation and quiet (no buzzing/humming etc):

- Antek
- Avel Lindberg
- Hammond
- Triad Magnetics
- Toroidy (poland)
- Plitron (since they changed hands however, I cannot find their transformers on the web)

- Any others ?

Is there any you would specifically recommend or specifically eliminate ?

Thanks

Hello everybody. I was hoping for advice on a 3 way build I've been tinkering with for some time - everything from the basic concept to implementation details. So here goes!

General intro: this was supposed to be a riff on the LX-mini, just a bit muscled up. So it uses an 8" up-firing woofer (Dayton RS-225) in a sealed cylinder base, with a 5 1/4" open baffle midrange (Peerless NE-149) and a SEAS DXT tweeter (H1499) mounted together in a 9" x 12" panel suspended over the woofer. A miniDSP 10x10 box does XOs and PEQ.

The "interesting" directivity patterns this would generate were acknowledged going in. Maybe it's an inherently bad idea. I was drunk on inexperience and Linkwitz's website!

After blowing two $100 DXT tweeters in testing, I took to doing measurements with an LR4 at 2500 Hz in place. Which was my intended XO. But the freaky on- vs off-axis behavior of the NE149 right there (which looks worse in my measurements than the spec sheet - maybe baffle effects?) caused warts that made me want to move the XO lower and try to bury that. So the screenshot shows my hacky attempt at a simulated 1600 Hz crossover, using driver data that was already rolled off at 2500. The shorted 2500 filter block is in the schematic to remind me it's already present in the acoustic data. If need be, I guess I can really implement it like this! But that leads into the questions:

1. Will I tend to blow the DXT trying for a 1600 Hz crossover? (I see the power dissipation graph in V-CAD -- kilowatts, what? -- but would welcome real-world experiences....)

2. Given that it is what it is, physically, at this point - should I try to tune it for steady power in room rather than on-axis/listening window, by boosting the mid-range? "Just listen to it myself", of course. I will, when I think I won't pop more pricey tweeter voice coils. What do other people (expect they might) prefer?

3. Am I interpreting the situation right here, thinking that the directivity & DI plots shown are just inescapable features of this sealed-OB-sealed Frankentower? Previous versions had even-grosser directivity issues around the crossover region. But I think the current gross directivity issues are just the bed I have to lie in??

I initially just PEQ-ed the drivers to flat, slapped on LR4s at 300 and 2500 -- thought it sounded pretty good, and got on with life. But now I am trying to do a more proper development.

Any insights are much appreciated!

Hi everybody.

In these days I'm checking a vintage piece of gear for a friend, an equalizer module that used to be part of a mixing console installed in the iconic Crystal Sound Studio. This facility opened in 1967 in Hollywood, CA, and housed a number of historical recordings such as many hits by Stevie Wonder, Weather Report and many other artists.



Andrew Berliner, the studio's sound engineer, built most of the equipment of the studio with a highest-quality, no-expenses-spared attitude. Then, in the late '80s the studio was bought by Roy Bittan, long-time keyboardist for Bruce Springsteen's E Street Band, who recently decided to auction most of the studio equipment.

This eq module I have here includes many high quality components such as many military-grade precision resistors, 10 Grayhill rotary switches (still working flawlessly after almost 50 years!), a proprietary API-style discrete op-amp and finally a fair number of ICs labelled 'NE535V', possibly made by Signetics.
I've never heard before about this chip: judging by the connections on the pcb, it's a classic single op-amp in a DIP8 case. I suspect it might be somehow considered as an early version of the classic NE5534, but actually I couldn't find any valid info on the net.



So here's my request: does anybody know something more about this mysterious vintage chip?

Thanks!

Neurochrome Preamp Power Supply

https://neurochrome.com/products/preamp-power-supply

Neurochrome Universal Buffer
https://neurochrome.com/products/universal-buffer

I am putting a pair of Icepower 200asc class-d boards into separate boxes. Do you need, or should you use a AC line filter with these? and if so, any recommendations.

Hello,

just to share an active rectifier, vertical mount, I designed for those who need to pair it with an clasic transformer based power supply, for those interested all the details is on pictures including gerber and bom file! I'm not tested it, but I have plan to build one for me, enjoy! : )

Features:

• Maximizes Power Efficiency
• Eliminates Thermal Design Problems
• DC up to 600Hz
• 9V to 72V Operating Voltage Range
• IQ = 1.5mA (Typical)
• Maximizes Available Voltage

Datasheet -> https://www.analog.com/media/en/technical-documentation/data-sheets/4320fb.pdf
gerber file -> https://www.diyaudio.com/community/attachments/gerber_active-rectifier_pcb_2024-02-22-zip.1276544/
bom file -> (suplier www.lcsc.com) -> https://www.diyaudio.com/community/attachments/bom_active-rectifier_2024-02-22-zip.1276552/

I've been into electronics ever since I got a ham radio license at 14. I love music and have been an audiophile for many years. Here's to further growth of music playing technology.

Hi gents ,
My monoblocks have the above heard through the speakers, the right mono is what I would consider a normal pop but the left mono sounds pretty bad , like a proper cracking sound . Also I the left mono needs more volume than the right mono ( the volume controls are separate on the Freya preamp )

They’re vintage British amps and look to be all original internally.

There are no schematics for them ( Alchemist Genesis)
So what should I look at replacing or testing?

Stock photo ( I can take some photos if needed)

I'm doing a project with two 3-way boxes (4" and 8") and I want to build the best box possible.
I was thinking about using 10mm marine plywood for the entire box and for the midranger I was thinking about using a fully sealed 7 liter egg-shaped box (But this will be done on a 3d printer).
After finishing the larger box, I would apply 10 coats of rubberized paint to the inner walls of the box (People from my city said it was necessary, why? I didn't really understand).
I'm thinking about putting audiophonic cloth on the front but I'm not sure about that yet.
Does anyone have tips or opinions?
I would like to know what would be the best design for a 3-way box?

I'm also thinking about buying the ingredients too (Speakers, components for the crossover, internal lining and everything). The amplifier will be a 100w 2.0 semi-tube amplifier.

I found an old pair of 8" 2-way speakers from the late 1960's in a thrift store and set them up in a small listening room. The sound was okay but vocals and piano sounded veiled.

I opened them up and saw that the crossover consisted of only one 5 uF capacitor in series with the tweeter. I had a couple of Solen 6.2 uF caps so I replaced only one for a side-by-side comparison. No difference in sound.

I also had some Jantzen .4mH inductors so I soldered one in series with the woofer. Vocals and piano from the same recording came to life.

On my to-do list is to purchase a UMIK-1 and do some measurements so that I can try to design a proper crossover for them (and others) but for now, this ad hoc crossover is doing fine.

This is the 3d printed speaker I made using dual aiyima 20w 2" drivers and basic zk502L amp.

What is it?

Hi !

I have 2 pairs of Acoustat and both pairs work fine but i want
to change all parts in the HV bias circuit.
one pair is a Model 3M having MK-121-2A interface and the second pair
is a Model 3 MEDALLION SERIES having the MK-121-C interface.
Both have same components on this HV bias board,
After some research on the web, a guy answered me to change the values of 5 HV capacitors from 3300pf
to 4700pf . MOUSER part number: 75-564R30GAD47.
Is it an updated ?

Other MOUSER parts numbers are:

diodes : 583-R5000F-B
500 Mohm Bias resistors: 588-SM104035006FE

My name is Dennis and I have been repairing / tweaking / building tube guitar amps for a couple of decades. Not sure how I have not been connected with this great site for so long.

Bob Heaton was my Dad. His funeral was on Friday. He was 90. He wasn’t a famous engineer or recording artist or anything, but he was my Dad and he was unique and much loved by all who knew him.

He wasn’t a member here since when he was doing DIY audio the internet hadn’t been invented! But I get the feeling that he would have enjoyed this forum and the conversations that go on around here. I’m sure he’d have enjoyed the thread about gravity too as he loved science.

He had lots of technical hobbies, these included Amateur Radio, DIY audio, electronics and Photography and he would also maintain his cars himself for many years.

He was my inspiration to take on some DIY audio projects.

Some of his projects included:

A Home made record deck based on a second hand turntable, but with a home made arm and a ceramic cartridge made with the help of one of his friends who had a lathe and a metal work setup.

A stereo amplifier. This used the Sinclair 3W pc chip if I recall correctly and the chassis was his own folded aluminium effort. It had tone and balance controls along with the usual volume control.

A pair of large bass reflex full range speakers based on the goodmans axiom 8” driver.

These were all built from chipboard and finished with a stick on wood finish laminate. The record player unit had a built in storage space for vinyl and one of the speakers also had a side pod for record storage.

He would love to sit at the apex of the speaker triangle on the floor so his ears were at the level of the drive units and would enjoy the stereo effect and the surprising amount of bass from a 3W amp. I think the drive units were rated at 6W. Tocata and Fugue would shake the room even at 3W.

When I bought Douglas Self’s audio books and showed them to my Dad, he remembered the name from many Wireless World articles. There was often an up to date copy in the house along with Practical Wireless and Electronics Today International, and an occasional copy of Elektor. These accompanied many of the Amateur Radio magazines like QST and the RSGB magazine. He had articles published in both.

The QST article was kind of a crossover between audio and radio. The idea behind the article was that to make Morse code signals easier to hear, you could limit the audio bandwidth to a narrow range around the carrier frequency. These days you’d use an opamp or two. It was novel because it used an acoustic resonator. It used a small loudspeaker from a transistor radio affixed to the top of a parallel sided glass tumbler. Doing a frequency sweep with our Wein Bridge oscillator, we found the resonant frequency. We then added a series LC circuit tuned to the same frequency to create a simple narrow bandwidth band pass filter.

It was surprisingly effective! You could easily hear Morse code signals that were otherwise buried in the noise!

He lived to see and hear my DIY audio efforts and was astonished at how much detail he could hear on my system and how good the bass was for such tiny speakers. He enjoyed hearing about my discoveries and the ways I managed to fix the self inflicted defects I had inadvertently introduced along the way.

He would have loved to see XRK’s photography thread on here as photography was his lifelong favourite.

He will be very much missed, particularly since he was really the only person I knew who could understand any of the DIY audio stuff! (Apart from the folks here of course!).

RIP Dad.

I confess that since I’ve begun designing passive crossovers, I’ve never use any other crossover slopes except the second-order. The reason is I don’t know how to deal with it without calculators. Lol

Thanks to Dickason’s cookbook, it provides a formula for calculating the Q-factor of the second-order filters. And I always utilize it. But that is limited for the second-order only.

Therefore, I wonder whether the other ordered crossovers; the 1st, 3rd, and 4th, have Q-factor?

And I’d like to ask everyone to share your designing procedure of any crossover orders besides the second-order filter.

For me, with second-order design, I use the standard resonance formula to find the corner frequency and, then, use the Q-factor formula, available in Dickason’s textbook, to find or adjust L/C values to achieve the desire Q.

Please share your procedures on other ordered crossovers to us.

Hi, I purchased some Chinese Accuphase clone Vu meters, and contacted the seller and he said they are to be hooked up via the speaker wires.. I am running 3 power amps in a single case (a 3way setup with each channel in a single amp case), and I want to run a single vu meter in each case...vs running 3 vu meters per case. My intention was to hookup the VU meter before my Xikica Crossover and run a cable to each amplifier case to power a single meter for that channel..

Is this possible? How can I do this?

This is the meter I purchased...
Just found this amazing item on AliExpress. Check it out!
$569,67 10%OFF | Reference Accuphase Audio Power Amplifier VU Meter DB Level Header Indicator Peak With Backlight Beautiful amp DIY meters
https://a.aliexpress.com/_mtW8SQ6

Once every while I Google "Cubo" or I get pictures send from happy Cuboteers, which I sometimes promise to upload to a variety of international forums that I visit. Having made such a promise this week without further ado:

Charlysays Cubo Subs 18NLW9400/ 18NLW9000:







Swarup Dalal Cubo 18's:



Cubo 18HP1060:



Cubo Based Sound System, South Australia:





Cubo 12 at ADEV2019:



Emanuel 6 times Cubo 12:




JP Dutreuilh Magnum Opus:







Rosssss224, Super Bass Horn, Cubo Kick 15:




Teknopaul finished his 5th Cubo 12:



Enjoy...

Hello
NAD D7050 amplifier shut off after 3....5 minutes and goes over standby mode.
No speakers or headphones connected.
All voltages of alimentation are ok
+ - 29v ok
5v..ok
5.6 ok .
Firmware...ok,I can update firmware with usb stick,no problem.
Reset ok.....no problem


Led is amber or white is power on...no red.


He can power on after one hour if I unplug it of power 230v.

Thanks

Service manual

https://elektrotanya.com/nad_d7050.pdf/download.html

PCB for DAC 8xTDA1387 (DAC ICs included and soldered) + tube output PCB.
3 sets available.

45 Euro+shipping worldwide.

https://i.postimg.cc/DwpTJmLn/IMG-3335.jpg

Hello,

I haven been using an old Marantz SR340 as my main amplifier for my music, driven by a laptop through the Aux input.
It worked great for years.
Then at some stage, Upon power on, I suddenly heard a loud abnormal pop and humming noise from the right speaker.
I repeat the power cycle and it was gone.

One day I turned it on for longer with the noise present to do some troubleshooting.

I suddenly smelled something and immediately turned the amp off. I know that smell very well.
The the smell came from the right speaker and then I knew immediately that the problem with the amp is DC into the speaker.
The amp was fine again after this but I stopped using it. The speaker is still ok as well b u I know it burned the enamel on the coil wire.

So what can be causing occasional DC onto the speaker in such an amplifier? Only sometimes.
It has a 2 driver transistors in the output stage and they are directly driven from IC Q701 = uPC1225H The transistors are Q703=2SD896 and Q705=2SB776

I have attached a small section of the circuit as I do not want to get in trouble for copyright etc.

I have an idea for a stereo system design that uses 1 stereo amp for each of the 2 speakers. How do I wire stereo amplifiers to drive a single speaker. It seems to get a lot of discussion and is quite a common setup but I can't find any concise / explicit diagram which lays it out in such a way that there can be no confusion.

Stereo amps are the normal / commonly available product so they're easy and cheap to buy but obviously not designed to drive a single speaker. So how do you wire them to do that?