Hi!
I'm about to buy technics amp. So i want to ask which is better, the su v65a or su v7. Also some opinion on the sound and how much they worth.

Say hello to my newest victim.



So far, I’ve replaced the stock power supply with a Jameco linear regulated power supply and the very crappy pot with a resistor ladder attenuator.

Currently, I’ve removed the relay closest to the pot, to make room for the new pot, but to avoid burning down my house can anyone confirm I’m bypassing it correctly?

Below is the pinout of the relay:



Using the above I'm guessing I just need to short these 2 pins on either side



The thing is the 789 has relay's up the wazoo. I figure this is the reason I can't check if I'm connecting the right pins, because the signal from the RCA jacks to this relay isn't actually connected, from another relay I'm assuming, until this thing powers on.

Am I doing this right? I've desoldered the relay and am just waiting for the go ahead to short pin 2 to pin 4 and pin 9 to pin 7. I know for sure that pin 2 and pin 9 are shorted to the attenuator's input for their respective channel.

Lastly, near the 24V input voltage there is a rail splitter to two 12v rails and the original pcb has space for two smoothing capacitors. I’m willing to bet they were removed due to cost constraints. Would there be any benefit to adding these back in, and what value capacitors I should put in?

Thanks!

I'm looking at building an amplifier from Class D modules (ICEpower). I am using balanced XLR cables everywhere in my system, so would like to build this amp with XLR input, even if the amp is not designed for balanced input.

How much of a problem is this? I thought I should be able to connect the ground pin to the chassis ground, and add a resistor between the XLR and the amp input? Or is there more to it? Or a potentiometer? I don't the correct value at the moment.

I am NOT a DIYer so it may be a stupid question. The seller doesn’t know what amp this but he says it is supposed to be a Pass Labs circuit. He bought it from someone.

Can you tell what model it is? And how well/cleaned it is made? Looks neat to me.

This is also what he mentions about the specs but I don’t know how accurate it is.

Very nice sounding 30wpc class Internal working voltage: two groups of independent double 35V DC



Pure Class A output power:

26W*2 8 ohm speaker

30W*2 4 ohm speaker



SNR: 108db

Hello all…been lurking for a few months…this place has been a gold mine of info. Thanks!
So I just finished my first kit build (Sambas) and I’ve got the DIY bug. I would like to build some MTM bookshelf speakers. Definitely LR’s and hopefully a center if that works.

Drivers:
Woofers: Dynavox LW6004HR-N
https://www.parts-express.com/Dynavox-LW6004HR-N-6-1-2-Honeycomb-Cone-Woofer-295-626


I really like these for aesthetic reasons and due to the manufacturer reputation and positive reviews.

Tweeter:
I wanted to use Dynavox tweeters as well but PE only has one model of their tweeter and it’s on clearance with only one in stock.

So I tried to get close to the woofer sensitivity and landed on these:
Morel MD 29
https://www.parts-express.com/Morel-MDT-29-1-1-8-Soft-Dome-Tweeter-277-010

Encloser: as far as material I haven’t gotten that far. I know I want large bookshelf that will go on stands.

Crossover: no clue! Hopefully I can get some help here 🙂

Questions:

1. Do my choices seem like a good idea?

2. How do I calculate box volume when using two woofers? Any help would be greatly appreciated

3. I’m hoping I can build a third for center channel…that’s doable right?

Thank you in advance!!! I’m not sure how this will develop but I’m determined to see this through till completion.

I'm selling all my capacitors for half price, plus postage (usually around £4).
Let's start at the most expensive, and my favourite capacitors. If only I could design a speaker around a single 2.7uF capacitor. There would be no way in hell I'd sell these. Not cheap, but by far the most natural sound.
2 x Audyn True Copper Max 2.7uF 630v - £260 plus £3.29 postage (would be £520! plus postage through hificollective) = £263.29



2 x Mundorf MCap Supreme EVO Aluminium Oil 33uF 600VDC - £105 plus £3.29 postage (£210 hificollective) = £108.28


2 x Audyn True Copper Max 0.33uF 630v - £78 plus £3.29 postage (£157 hificollective) = £81.29


2 x Mundorf MCap Supreme EVO Aluminium Oil 5.6uF 800VDC - £48 plus £3.29 postage (£96 hificollective) = £51.29

Hi

I’m building a little hifi setup that’ll use XLR interconnects and speaker cabling. This is just for aesthetics but It’ll be balanced where applicable .

What is the rule of thumb for when to use a male or female SOCKET? I real that it’s:
Outputs = Male
Inputs = Female
So…
Sources: (media player): male socket,
Preamp: Inputs: all female sockets; Output to amp: male sockets
Amp input: female
Does this carry over to speaker cabling:
Output from amp: male
Speaker: input female

Correct?
Thank you

Hi!

Does anybody have more info on the driver array Perlisten uses?
How does it work? What type of crossover and frequencies do they use?

I think the drivers might be Seas custom units, some of the components look like Seas made, but I am not shure.

If one would like to try it out DIY style, how would one go about? What drivers to use?

In my simple mind the use of such small drivers and membranes for the mid register could possibly be a superior sounding solution.

Would like to know what there is to know about this configuration, especially when it comes to crossovers used.

So I couldn't figure out why my amp sounded very bad until I finally saw the (short -120v) and (open-240v) selector connection holes on the board. I connected a jumper and then tested it, with amp disconnected because that made it easier to inspect with my multi-meter and I finally had my full voltages, 72v, not the 38v I had before. In my moment of joy I rushed and I forgot about the capacitors. When I connected the smps to the amp the connection arced loudly and with a blueish white color. The hbp500 smps had a blown mosfet, fuse, rectifier, and driver. I've ordered another smps because it'll be nearly a month to get most of the replacement parts that were blown and I can't find the driver part numbers on the power supply because they have obliterated the part#'s anyways. I cannot afford to pay another $40 for a third smps I really need to know if the amp could blow my new smps and how I can test it if it can. I do not have an oscilloscope yet only a multi-meter right now. Thanks in advance.

I revisited the HummingBird PCB layout, separating the input stage and moving the BIAS trim up, plus some other minor updates.
I think i'll go for a test.


Gerber files:

Sold out!

- Galaxy GX383 chassis (2U, 330x230mm, iron top and bottom, 3mm silver front panel, sealed)

- Galaxy GX387 chassis (2U, 330x170mm, iron bottom, 3mm black front panel) + top substitution with 2mm aluminium cover GALAXY 347-387 without any hole (unpacked but unused)

- Rear panel Galaxy 343-347-348 (1U, 40x330mm, 3mm black, sealed)

- Additional 2mm aluminium cover GALAXY 347-387 (330x170mm) without any hole (Sealed)

- Front panel Galaxy 343-347-348 (1U, 44x334mm, 3mm silver, sealed)

- Front panel Galaxy 383-387-388 (2U, 84x334mm, 3 mm black, drilled but unused). Features holes for Alps RK27 pot centrally and 6mm hole at 50mm from the border to be used with a switch or led holder (can provide it in black or chromed)

- Rear panel Galaxy 343-347-348 (1U, 40x330mm, 3mm black, drilled and used). It is this very panel and I can provide it with new RCA connectors and IEC filtered socket

- Large and small black knobs (Not in picture. Sealed)

Two pieces of TDA1541A-R1

SOLD




Op-amps -
4 x LT1028 DIP unused - £25
4 x LT1122 DIP unused - £20
4 x OPA604AP DIP unused - £10

Used, selling together as set -£10
2 x NE5532AP
4 x NE5534AP
2 x OPA2604AP

Hi friends!
When you‘re working with shielded/coax wires, which usually have quite some strands (…), how do you connect them to the connector/solder-lug?
Most of the times the shields sums up to 1-2 mm² or even more. Do you cut part of the strands?

Hello, could I ask for an evaluation of the design of this amplifier? It should be able to supply 360/600W to 8/4ohm. Alternatively whether anyone would be willing to do tests and pcb? Thanks for the replies.

4x Rhopoint Resistors GG102D 120Ω 0.1% - SOLD

Asking 50€ + shipping costs and any fees.

If the price is off let me know or make offers.

Please contact me through PM.

First 3 faders don't work.....sending midi CC messages even not touching them. I desoldered first one just to check....MIDI OX sending values even without it. Strange thing is that 3 rotary pots above the first 3 faders act like volume control and they supposed to be pan knobs, all the rest works fine. IC on PCB 74HC4052d, 74HC1640 .Brain is ARM STM32F103. Which chip controls midi input? Even when i change the midi channel and midi CC number for the first 3 channels it acts the same.....HELP BROTHERS!

video https://streamable.com/a6cx3l

Of the best sellers, how many of a kit get sold?

Have some of you double driver XKi and Karlsonator worked out well?
For a little one I'd liked to try two Eminence Beta8A in parallel - with K-tube on top.

For more impact - two Pyle PYM1298 (Eminence built and same as Kappa12A)



For

For

I will buy 2SK2013 and 2SJ313 only original Toshiba.
Does anyone have them?

I have just had the strangest experience with my pair of DCX464. I bought them new, they sat in a box for around a year and then I took one out and did a few sweeps at living room SPL level to measure the FR and impedance with a horn. I put it back to the box and pulled it out another 9 months later. Again, I did a few sweeps with a horn and without it at comfortable levels - I would say 95 dB/m absolutely maximum, more probably less - since I did measure mostly a few cm from the mouth. I used the log chirp from Clio Pocket and a solid state amp I am normally using, which has no problems at all (except for a little noise and hum, which is another story). This time I took out both - measuring one on a horn and one without it. I got some strange results, so I did more measurements swapping the drivers, etc. The unused coil was always shorted or connected to the other channel of the test amplifier.

The drivers were sent back to BC for investigation since one unit had suspicious measurements on MF FR and Z, the other unit had suspicious measurements on the HF unit. They took the drivers apart and the membranes were smashed (they say, I have not seen any evidence of that). They suspect severe overload of the drivers (which has never happened!), but were kind enough to replace all the membranes free of charge.

I wonder what does one need to do to destroy the membranes of the drivers (all four!) - what voltage/frequency can damage these without a horn and on a 300 Hz horn? I did nothing but the FR sweeps. I have measured compression drivers like this for many years and none was destroyed by that (even the tiny 1" compression tweeters). I am puzzled, what could have happened? Either I have destroyed them with the (relatively silent) sweeps or they must have been damaged before I bought them new in a factory sealed box.

Hi All,

I've 4 x Quasimodo V4 PCBs for sale: 8 €/each plus shipping.

Regards,
Vasco Soares

I have a Pro-Ject Classic SB turntable that fails to power on. I have replaced the Speed Control Board and the Power Board and still no luck. The last thing to try is this motor, but i'd like to find a simple way to determine if it is good or bad. is it possible to use a multi-meter to do this or is there another method I could use to get power to it without the speed board and power board? Thanks for your help!

If I want to add a second driver (the same driver, in series) to a design, would I have to double the effective cabinet volume for the same response? I haven't quite got to grips with designing a cabinet with multiple drivers that share the cabinet volume. Is it simply additive, does one driver bound the others (where there are a mix of ranged drivers) or is there a more complex interaction.

I am wondering, what are the pros and cons of single 12inch vs 2x8inch used as woofer in a 3way?

Cons area variances between them is around 10%, 8 inch take less space and is more WAF friendly.

12 inch makes big box.

Both can go deep simiraly, a lot of pro 12 inchers even can't go below 40Hz...
But there are some who can 😉

Just thinking about my future build, and if we would put aside form/space and higher efficiency in pro drivers, than...

What's the reason to buy single 12inch vs 2 8inch to act as woofers in 3 way?

New, never used, UMS compatible TO3 mounting brackets for 2017 VFET amp. These were for the original VFet amp kits from 2017.
$120 including USPS flat rate box to CONUS.

1 pair Sony 2sj28 KF-33 from CircuitDIY Acronman
$225 including USPS flat rate box to CONUS

Both Brackets and 2sj28s combined for $300 shipped USPS flat rate to CONUS

PP F&F

Life has intervened 🙁
Up for sale is my AkitikA 1KHZ2PPM 1 kHz Oscillator kit. Please see https://www.akitika.com/1kHzOscillator.html for more information.
Asking $50.00 shipped. CONUS
Thanks for looking!

- SOLD -

Selling this VFET amp from the original/first lottery. As everybody knows, designed by Nelson Pass. Beautiful sound! 🙂
The amp is in perfect condition. For the wiring I opted to use Duelund cable - which I've found to sound awesome.

The kit cost 650usd when sent to Finland - plus the Duelund cable. So looking for 700 euro. Buyer pays shipping. Will be packed to withstand UPS handlers.

- Jukka

Hello friends, I'm still learning and asking.

Login to view embedded media
Is this noise that comes out of the opt normal? Is it oscillating?
I am using a square wave at 1khz, 1vpp.
I tried it with sine wave and at some frequencies it does the same thing, is it something bad?

I have it connected with a load, the oscilloscope and a function generator.


Another question that I was looking for in the forum and I didn't know how to search for it.

Thank you for your time and wisdom.

Hey, I am a complete newbie and currently planning my first project.
I want to build a simple A/B switch with volume control. I found plans and ordered parts, now the only thing missing are the wires. On the website I ordered my parts I only found "audio cable" but only on 100m rolls, wich is way too much.
Can I use cables from old/broken audio equipment or XLR cables?
If not, what do I have to search for?
Greetings

Hi all,

This is my first post. I am trying to get started with crossover design in XSim and saw in several places that you can extract the frd and zma files from the manufacturer's datasheet with the FPGraphTracer tool. All of the links to that download pull up a 404 Not Found webpage. I was wondering if there are any alternatives to that tool or if anyone has any other means of downloading it.

Thanks!
Colin

This is An Acoustic Research AR-XA in fantastic condition, plays and sounds fantastic.
Solid Walnut plinth,
It has a lightly use Grado Black cartridge on it.
Has many upgrades including Tonearm Sapphire bearings,new Springs, new Litz wiring, RCA back panel jacks,and many more listed on the invoice picture on the listing.
Local pickup only Huntersville, NC area
$600

Does anyone know where I can buy more of this PCB board? I bought it from Watts Tube Audio ages ago but I believe they are out of business. I believe it was called “red swirl”. It’s 1/8 thick. I can’t seem to find it anywhere.

thanks

Need help in finding an Accustat medallion schematic & parts list for Accustat medallion MK-141-B. Want to upgrade parts.

This is a little bit of software I wrote to meet my particular preferences for a music server/player:

• Play random albums (rather than individual tracks).
• Run locally (no dependence on 3rd parties, or an internet connection at all)
• Use a normal web browser as a client (so it works on any device, including phones, with no need to install anything).
• Support ReplayGain (so I don't have to keep adjusting the volume up and down, especially for new vs. old recordings).
• Glowy neon and LED bits (because why not).

I released it to the public in case anyone else finds it useful, but bear in mind that since I wrote it for myself, I didn't put any effort into making it easy to use, or any thought into what features other people might want. Also note that it has no auth, so don't expose it directly to the internet unless you want everyone on Earth to have access to your music collection.

Here's what the client looks like in a desktop browser:


And in a phone browser:


And a short video clip of the spectrum analyser:


To run the server you need to

• Install both the .NET 6.0 Runtime (or Desktop Runtime) and the ASP.NET Core Runtime.
• Extract Paramuse_1.1.zip to a folder somewhere.
• Edit appsettings.json and set BasePath to where your music is stored.
• Run Paramuse.exe
• Wait a while for it to scan all the music (should take just a few seconds with an SSD. It might take a minute or two if the music is stored somewhere slower). Only MP3, OGG and FLAC are supported.

It should work on Windows, Linux and Mac, but I've only tested it on Windows. It should also have relatively low hardware requirements, but I haven't experimented with that either.

Once the server is running, you can connect to it with a web browser on port 8080, e.g. if the browser and server are on the same machine, this will be http://localhost:8080. If you want to connect to it from a different machine then you'll need to find the server's local IP address and use that instead of "localhost". You need a newish browser (current Firefox and Chrome work; old phone browsers may not).

The client has just the bare minimum needed to play albums. In the box at the top it shows details of the currently playing track, with some controls (prev/next track, play/pause, shuffle, a timeline, and a volume control). There's also a spectrum analyser just because I love those.

Underneath is a list of every album that was detected. All audio files in the same folder are classed as a single album, so it only works properly if you organize your music well. The actual names will be read from ID3 tags where possible. It will also get album art from ID3 tags, or from separate image files if either are present. There's a play button next to each album to play that album directly. You can also click on the album to expand it to list all the tracks it contains.

There's source code available on GitHub or my own website.

Great horns to replace those honky Klipsch metal horns
will throw in large format drivers for $100 extra
Professionally built
$600

Hi all
I'd like to use 4 irs2092 in parallel on one +-65V (1500W) source, like I saw it in several youtube videos
(all components from aliexpress)

• https://www.aliexpress.com/item/100....order_list.order_list_main.22.27df1802OC3TUx
• https://www.aliexpress.com/item/100....order_list.order_list_main.58.27df1802OC3TUx

While with only one irs2092 everything works fine, problems arise by adding further irs2092 in parallel.

Problem:
impulses at loudspeakers with 2Hz to about 10Hz randomly (rally noisy loud spikes)

so there is a kind of interaction of these amps , ..no idea what is the reason

I already tried:

• changing the audio input signal (different Bluetooth receiver & dsp boards) -> no impact
• different combination of irs2092 (to check if any of these is particularly damaged) -> any mix gives similar result (->no single defect of one amp)
• R13 is 101 (not sure if this plays a role as described in other posts)

I only have basic electronic and soldering skills, and would be thankful for your support.
best regards

Iancanada 37A Sine Pi Finished with SMA cable. $65 with cable plus shipping from the US.

and why?

Hi guys. I recently bought a Cambridge 640a v2 amplifier and I have a problem with a flashing LED. When you turn it on, you hear a click and after a while it goes into standby mode. diode signal shows an error requiring DC service. I checked R42, I am publishing photos of the measurements. Could this be the reason?

I've been tweaking crossover networks of ADS L1590/2 speakers.

First, let me explain the reason for this modification. The sound character of these speakers tends to lean towards bright, opened midrange and, some people describe it as a little bass-shy. For me, I consider them to be too pale though. The objective is to gain more bass and tame the midrange.

Since each speaker is about 42kg in weight, I didn't pick them to the measurement. I just use simulation of the crossover instead, along with reading "tweaking crossovers without measurement" thread.

Okay, here is the simulation result of the original crossover. As you can see, there's definitely a spike on the upper midrange, around 1.5-3.5 kHz, as depicted in red circle.



I started tweaking by adding single resistors to tweeter and midrange circuits and lowering low-pass filter of the woofers. This is aimed to reduce midrange and tweeter levels.

Next, I move to tame the midrange spike. I performed by adjusting the low-pass's capacitor of the midrange. From 15uF to 37uF, the response curve has now become flat.



Here I have some questions.

1) According to the online calculator, the original 15uF and 0.4mH filter gives Q of 1.162, whereas the modified 37uF and 0.4mH gives Q of 1.825. Both Qs are considered to be quite high. So, will it cause any problems, e.g., impedance issue?

2) Will it cause problem from using the 37uF for low-pass of the midrange in which it's larger than 33uF of the high-pass's section?

I have FOUR (4) Dayton Audio RS180-8 7" Reference Woofer. asking $50 each, $100 per pair plus shipping or buy all four for $200 and get free shipping in the USA

I have TWO (2) Dayton Audio RST28A-4 1-1/8" Reference Series Aluminum Dome Tweeter 4 Ohm asking $50 per pair plus shipping.
these were in a custom set of studio monitor speakers that were finished but never used.

or buy ALL for $250 with free shipping in the USA. may consider offers.

Mirage 460. Voice coil lead broken. Tried to solder without success - just smellt burned cotton. Any suggestions?

Hi,

i have a "WHAMMY" Pass DIY headphone amp circuit board for sale.
Thread: https://www.diyaudio.com/community/threads/whammy-pass-diy-headphone-amp-guide.317803/#post-5317268

Cost: 20€ / pcb
Shipping to all destinations in a padded envelope without insurance or tracking (or you asking for other options):

• D (without islands): 3€
• UK much paperwork for me to the customs declaration, so 10€ shipping costs + 2€ paperwork = 12€
• World Wide: 5€

This ist last version with both resistors on board. ;-)

Best regards ...Carsten

In other words; Are kick bins "invented" to relieve bottom and midds from the high power content in the kick drum region of the frequency spectrum? Thus needing higher durability/power rating relatively?.
-Or is kick bin simply the nickname for second lowest cabs in a 4 way system?
Cheers?

Hi everyone,

Here is a quick description of the repair of the switching power supply -SMPS- of a Beolab 3 active loudspeaker (Bang & Olufsen, circa 2010).

Symptom described by the old lady who entrusted it to me for an attempt to repair: the speaker no longer works. The other one is OK, so she's listening in mono. I notice that the indicator LED does not light up when the speaker is plugged in. I then suspect a power supply problem. I'm not too familiar with that type of PSUs but we'll see...

After disassembly (thanks to the excellent tutorial on Youtube), I quickly access the circuit board of the power supply.



I can easily see that an SMD filter capacitor near the D501 diode bridge has exploded. I don't read any value or code, so I unsolder the second properly to measure it (10nF). I will change both.



I then take a look at fuse F501, it is cut, to be replaced! Not sure that the diode bridge is still operational, I unsolder it to test it completely out of the circuit, but during the operation I damage it. It's (solidly) soldered to the double sided circuit and my (low cost Chinese) desoldering pump isn't powerful enough to clean everything thoroughly, a pin in the bridge jumps out in the extraction. No big deal, I have to order capacitor and fuse, I'll add the bridge...

I receive the components in 2 days (thank you Mous.., perfect as usual), I resolder the 4 components (1 x Through Hole 250V IEC TL SL 2.5A TR5 series 382 fuse, 1 x KBP208G rectifier bridge, 2 x SMD Ceramic Capacitors 250VAC 0.01uF C0G 1206 10%). 2 photos: work in progress, finished:



Quick test after reassembling the cables, the red LED indicator lights up.



All I have to do is bring the speaker back to the lady and test it on signal. Hope it can help someone if needed. A new PCB sells for 300€.

I'll keep you informed when it's plugged on the B&O system again!

I bought Yamaha A-500 with defect for 30 bucks .. I replaced burned output trans, it working, but speaker protection circuit does not switch output relay.. I am not sure, if is there delay only , or is there some voltage detection yet ... Any advice? I have to set up bias(don´t know exact value) and offset (don´t know where)

Here is schematic...

You made want to stop reading here, if you're wanting a full detailed review. I condensed an email from my best friend about his experience is this past weekend. I trust his very experience ears, along with the other audiophiles who were there. Here is what he said, "The bottom line is, I sold the amp to someone who wanted to hear for themselves what it sounded like.

I took the amplifier to a meeting with four or five audio gear nuts. We were able to listen on very revealing reference speakers in a really nice treated room. We had been listening to a $2,000 Class A B amplifier in a system, and had been listening for over an hour to the wonderful sound. When the mini gan 5 was put into the system, people started losing interest. The amplifier was bright compared to the class A B amplifiers. It also created listener fatigue. The same exact songs we had been listening to were now irritating. I could go on forever about the highs mids and lows soundstage excetera, but what I just wrote above is all I needed to hear to sell the amplifier within 3 hours. Class D is still light-years away from class AB in sound quality to our ears. The differences were noticed within 10 seconds by everyone. When you take the magic away, the human brain notices quickly.

this is my first subwoofer build, hence I'm still guessing and relying on modeling software. Previously i read on my friend's built which used DVC of this subwoofer, when looking at good price of this item without breaking my wallet and good result on simulation, i think my friend had a good choice on drivers.

However they are discontinued, but I'm lucky to get second hand item - 3pcs already, looking for 1 more - but they are single voice coil version. When I put into online simulation, it seems SVC has lower Fb than DVC but double in box volume which is not an issue since this is for home subwoofer.

When i google on recomended box, most of the thread lead me to car subwoofer which ended between 1-1.25 cu.ft volume but simulation give me 2.2 cu.ft. I have no issue up to 3 cu.ft box volume.

Can i rely on software simulation for box volume? which volume should i build? i will use 2x18mm plywood with internal bracing and powered by nu3000dsp.

It will be very helpful if anyone can share any experience on using SVC of this item for home sealed subwoofer.

btw this is just for stereo music, no plan to make any home theater

These days here in Greece we are mourning a giant. The great, composer Mikis Theodorakis is no longer with us. But he is in our minds and hearts forever.

I have 1 set of boards left for sale.

PCB: 1,6mm, 2oz, green, HASL
Price: 20eur + shipping
Payment: Paypal

On page 556-557 Jones shows a QBasic program for calculating a Type A step attenuator resistor stack. I copied this exactly as shown into an online QBasic compiler (qbjs.org) and I cannot derive anything meaningful. My results for a 10k 'pot', 2.5k output, 8 steps, 3 dB per step:


Note that instead of each line adding 3dB each time (0,3,6,9,12...), it instead concatenates the term into 0,03,033,0333.... and of course terminates after 333dB.

Anyone played with this before, or know more about QBasic that can spot an error in the book?

Here is a link to the qbs.org compiler:
https://qbjs.org/?code=Q0xTCkE9MApC...CPUIrQwpBPUErRApOPU4rMQpMT09Qzy8gICBSLULHNC4i

There are not many 1" CDs with 1 3/8" thread available.
I nice exception is the BMS 5531ND for example:
https://www.bmsspeakers.com/fileadmin/bms-data/product_data_2019/bms_5531_datasheet.pdf
I am wondering why?

Hi.

The resistor R47 - 22R1 has failed in one of my channels. Would anyone know its wattage rating? I can only go of its size, which is 6mm long, 2.4mm wide on the ends, and 2mm wide in the centre.

Thanks

Can someone please check the math below and comment if anything looks wrong?

I'm buying a TPA3250 based Class D amplifier. It states it can take a 18v-32v DC power supply. I plan on only using a Dell 19.5v / 3.5amp out (65w) laptop power supply and don't need a lot of power for the speakers in question.

I estimate I will get a max of 17w per channel into 8 ohms (or 31w into 4 ohms)

I'm trying to design a 25W stereo amplifier for my senior project using the LM3886 IC but seem to be running into some problems with my power supply.


Here is the design I made in LTSpice, its mostly taken from the datasheet. The power supply is on the same PCB as the amplifier itself.


I am powering this amplifier with a 240VA transformer (40VCT, 6A) (https://www.mouser.com/datasheet/2/410/F_273U-780989.pdf) . I've done some general unloaded voltage testing on the transformer and have found no issues. I chose this transformer rating through calculations done with the equations provided at the bottom of the LM3886 datasheet.

Most recently when I plug the transformer's secondary winding to my PCB I blow my 10A fuse that is located on the primary winding. How do I go about troubleshooting the problem if I am unable to put power into the board and test things properly? I have triple checked the MUR860 diodes that are located in the center of the board and everything appears to be biased correctly.

I do not know if my transformer and wall socket models are very accurate, I set the series resistance to 10 ohms since it resulted in a realistic current for a wall socket in the US. Because of the voltage step down however (120V wall socket to 40VCT), my current is 3 times what is in the primary winding in LTSpice and is leaving me extremely confused on the next steps. My only idea is to add a current divider circuit between the secondary winding of the transformer and the voltage rectifier in order to get a more ideal current entering my LM3886 chips.

Another thing that I am confused about is when I calculate the voltage and current that my power supply should be feeding into the IC (based on the datasheet and my desired power output), I get about 20V (positive and negative) and around 3A per amplifier circuit. When I run tests on LTSpice however, it seems that the input impedance on the IC power pins is so high that I am inputting current in the order of micro amps. Is this a result of simulating the IC in rest mode (powered on but not playing music)?

The Live Edge Open Baffle speakers took 1st place at the Parts Express 2023 International Speaker Design Competition, top ranked against 58 competitors.

When my friends visit, most have never heard anything like these. When you play classic Miles Davis recordings, they have a huge, lifelike, warm, present sound. If you play Rush or Porcupine Tree, they handle the dynamics and bass with ease.

$30,000 OBO.

They have stunning imaging, a huge sound stage, high efficiency, enormous dynamic range.

They are made from gorgeous 1.5" thick slabs of Live Edge birch purchased at Big Red Sawmill in Palmyra Nebraska.

They were featured on the cover of AudioXpress Magazine, January 2021. Numerous hobbyists have built the design based on plans on DIYaudio. These are THE original speakers, designed by myself, Perry Marshall. Cabinets built by Seth Cothron.

I am parting with them because it's time to make room for more new designs.

These are active DSP driven speakers. They need to be biamped (any high quality 4-channel amp, or pair of 2-channel amps of your choice). They are shipped with a MiniDSP 2x4HD Digital Signal Processor. It has inputs for analog, USB and fiber optic cables. DSP is "Photoshop for sound" and allows miracles that are impossible with old school passive crossovers.

When room reflections don’t match direct sound from the speaker, it sounds unnatural. Textbook speaker designs pretend the room is not there. But not only does the bass have room modes and standing waves, but the mid and high frequency reflections add LOTS of clues for your ears. Good clues make your ears happy.

PERFORMANCE SUMMARY

• 30Hz to 25KHz with silky-smooth response in a real room that has real reflections. Not just in an anechoic chamber.
• True Constant Directivity sound pattern 30Hz to 25KHz so imaging is superb anywhere in the room
• Open Baffle Dipole sounds great even behind the speakers
• High Efficiency – 95dB 1 watt/1 meter. Sounds great and plays loud even with “flea watt” single ended vacuum tube amps
• High Power Handling and High Output – 100 watts & 115 dB running full range; 500 watts & 120 dB with subwoofer
• Near-perfect impulse response
• Near-perfect phase response
• Low Distortion (<2% above 60Hz; <1% above 150Hz at 90dB)
• Easy to drive: 8 ohms (4.5 ohms minimum)
• Live Edge wood is so beautiful, non-audiophile wives of non-audiophile men gasped when I showed these on a screen in a Zoom meeting.
• 3-way system is bi-amped (not tri-amped) using a MiniDSP 2x4HD.

It is not possible to buy anything like these at any hifi store. Open Baffle / Dipole designs are loved and celebrated for their room-filling sound and lack of boxiness, but are extremely rare. Live edge real wood is equally rare. They have a HUGE "Wife Appreciation Factor" - spouses love the natural wood. Competition Judge Jerry McNutt said, “The best way to not sound like a box is: Don’t use a box.”

The Live Edge Dipoles sidestep every pitfall of conventional designs. Giant notes roll out of the speakers. You enjoy a huge sound stage. You are immersed in 3D ambience, clarity and resolution. Dry recordings become spacious. Drums and toms hit with visceral, fist-on-sternum impact. These hold their own against the world's most prestigious designs - Wilson, KEF, Focal, Genelec, Estelon, YG Acoustics.

Constant Directivity means you have flat frequency response on axis, and as you turn the speaker in any direction, the level steadily drops off axis, but the octave to octave balance remains flat. Then imaging will be great anywhere in the room.

You can walk all over the room—even stand on the far side of the left or right speaker, and you still clearly hear the other speaker across the room and the imaging is still stable. There is no one “sweet spot.” Music sounds fantastic anywhere you go in the room. You can walk around and behind the speakers and they still sound great!

They are equipped with 18" Eminence Kappa LF woofers; 8" Radian 5208-C mids, with Beryllium diaphragm Coaxial compression driver firing through the center. A rear firing tweeter means the energy from the room matches direct sound. An L-Pad for the rear tweeter allows you to adjust balance.

The front-firing Beryllium tweeters are extremely transparent; bass is rich, expansive and authoritative; thorough top-to-bottom coherence and integration; warm, ambient and enveloping stereo image. They effortlessly fill a large room to overflowing with palpable output and dynamic range.

They sound best 3-5 feet (1-1.5 meters) from a rear wall.

On DIYAudio you will find extensive discussion of these speakers with full technical details. The photos here include in-room measured frequency response, impulse response, step response and polar heat map.

Shipping is by truck to the continental USA and will be arranged. Local pickup is encouraged, from my home in the Chicago suburbs. You can also come for a listen.

Hi all. I know this was discused earlier, but the topic is soooo old...
So, i made my own in ear monitors with Knowles BA drivers GV-32830-000 and, obviously the next few days i spent with the big issue (for me):
HOW DO I MAKE THE SOUND BETTER? WHAT KIND OF DRIVER COMBINATION SHOULD I USE AND WHAT KIND OF CROSSOVER I SHOULD MAKE?
So, probably the main question in this thread would be...... : Are there any templates for buildin your own decent sound with impedance, resistors and induction metering?
Is it possible to find a guide or something so i could build a better sounding CIEM's?

Thanks in advance.
Sorry for my grammar and English mistakes, im not a native English speaker so to say.... 🙂

Has someone used one XLR cable to replace the double phono connection between the preamplifier and the power amplifier. My connection is about one metre long.

Spent a good amount of time online but can seem to troubleshoot this. I should note that this is my first Thorens TD124 mkII so I’ve never experienced one in top working order.

When I got the turntable the idler wheel seemed to have issues with engagement. I’ve since gone through a detailed cleaning as per the many resources online and while everything is running and functioning great, the idler wheel does not engage the platter. It just sort of flops around.

I understand that with the platter off it will not fully engage.

Out of curiosity, I put an extra turn on the idler linkage spring to pre load it. This made the idler engage and the platter spin but this should not be the fix. I worry that this is putting stress on all components in the chair and will induce rumble. Also it seems like the clutch can’t stop the platter in this state.

I’ve cleaned and lightly polished and lubed all linkage parts and there is no build up of old lube.

Any help would be appreciated!

Good evening am looking for a pair of gently used pair of the Alpair P7’s or brand new. Here’s a picture of them. You can e mail me at Jmboo1922@gmail.com. Thanks Jeff

Hi all,
new here and pretty new to the DIY DAC world.
I have setup a Raspberry Pi 3b+ with PurePi, FifoPi and a Innomaker DAC 5122 on top.
I have powered the FifoPi from the PurePi 3.3 power supply with short cables.
All other connections are through GPIO.
All seem to be up and running, but I cannot get any sound out of the DAC.
I tried different Moode settings such as Allo Boss DAC in slave and non slave mode, or IANFifo II but nothing seem to work.
Any idea what I might be doing wrong?
If I remove the FIFOPi and put the dac directly on top of the raspberry, it works.
Thanks for your help,
Simone

Building another SSE! Went to get another Temco Motor Run Cap, but they appear to be out of stock everywhere. Would this one work as an alternative? https://a.co/d/0S0hZmo

Is there a better option out there? Something perhaps better sounding (if this component affects sound) or better looking?

The KA-Electronics Flat, Balanced Input/Output MC Preamp PC board, normally $39.95, is now $20 Off for a limited time.

Product information: https://ka-electronics.com/shop/index.php?route=product/product&path=63&product_id=122
Construction information: https://proaudiodesignforum.com/forum/php/viewtopic.php?t=1179
ZTX851 transistors are available here: https://ka-electronics.com/shop/index.php?route=product/category&path=65



Use Coupon Code "DIYAUDIO20" at checkout. International shipping available.

Enter the coupon code at checkout here:

For sale a pair of Rods negative bias psu regs with pair raw dc psu. Price would be 50eu plus 6,50 euro shipping inside EU with tracking. The boards are suoerb build and working without problems. Mire info on contact. Payment paypal for friends.

I'm having a Toslink out on my TV and would like to dmux the singal to I2S. Any suggestions what to use for that task? I was looking at a board with a DIR9001 IC but I'm not sure if it would do a good job or not. Here is the link to DIR9001 based board.

If you are doing nothing more than spin your loudspeaker you will end up with a living room evenly covered in vomit.

Best regards
Bernd

I have bought a pair of seas full range speakers. And now i hope
the good people in here will give me some input on what type of
cabinet is the best for this driver.
Should i go for a horn construction like Dallas or Jericho or a closed 60 L box
or 70L bass reflex box both the closed and the bass reflex boxes are found in the app notes from seas.

http://www.hasaudio.co.nz/images/SEAS/H1597-08_FA22RCZ_Datasheet.pdf
http://www.hasaudio.co.nz/images/SEAS/FA22RCZ_AppNote.pdf

All sugestions are welcome in this prosess. I just hope i get a lot of ideas to try out.

Hello friends I am new here and found this forum very interesting. Thank you for accepting me.

Hi,
I built 4 coaxial speakers according to the B&C CX10.64 reference design. For initial testing, I bi-amped them. Completely blown away by the sound !!!

Next step is to build and install a crossover. Unfortunately, the information the B&C provides is limited to the schematic with component values. (see attachment)
I understand, of course, that they don't want to name brands here, but I get a little lost when searching for components.

Can you help me on my way with this. There is so much information that I can't see the forest for the trees.
I had already understood that low resistance coils (thick wire) and high voltage capacitors help reduce distortion.
But where is the sweet spot? The speaker in question is a coaxial type with 500W continuous power.

Also, I think it would be useful to use some kind of protection to protect the HF driver. But what?
Any other things I should pay attention to?

Thanks for your answers.

Regards,
Johan

Firstly, I know absolutely zero about DACs! So I would like advice on how to improve the performance of my system in subjective terms of ‘being there’ with - mainly - small scale classical music. I have a large collection of mainly older CDs.

My present CD set-up includes a TEAC T1 Transport (which is a troublesome thing) and a Philips 850MkII used for SPDI/F output only. My DAC is a SABBU - Second version. So any recommendations MUST have SPDI/F coax input. At my age I wish to spend less than a fortune and will consider Ready to Connect boards, good fully sorted used boards/units. Any used offers must be from UK/Eu.


[The rest comprises a well built Hypnotise pre, a Bonsai KX2 Power amp (Also a Bonsai first version NX, Joachim Gerhard ‘Sonics Allegretto’ speakers all connected with Yamamura Churchill
Ic and spkr. cables].

Being ‘beyond elderly’ (82 in 5 weeks) and have a very shaky right hand so only the simplest soldering is possible. I have a few useful chassis units suitable for boards and a few transformers, but would prefer a plug and play solution which will comfortably out-perform the SABBU.

Many thanks,

Brian

Hello all,
may I introduce my newest build:
A power amplifier, only with TO39 metal can transistors (-> this project on my own page, in german)

Some month ago I got a large amount of old unused electronic parts.
Including many transistors in TO39 housing: BC140, BC160, BSX45; also many electrolytic capacitors of larger capacity: 4700uf etc ..
Too good to throw away, so what can you do with it?
I got the idea to build an amplifier with it and only use these TO39 transistors, even for the output devices.
Some might think that's nonsense, but it doesn't matter: here the thing is and it works.



After countless LTSpice simulation runs, I finally made the PCB layouts and had the boards made.
Since you always order several boards, I designed the layouts in such a way that the remaining boards could also be used for "normal" amplifiers, e.g. with TO126 and TO264, SOT-93 or similar transistors. For this reason, the TO39 output transistors sit on their own circuit board.
The capacitors in the parts convolut were all axial, so the power supply board has space for axial and radial smoothing capacitors.



The power supply is regulated and offers a stable voltage of + 20V and -20V.
More is not possible for the amplifier, since the transistors BC140 / BC160 can only withstand 40V.
The supply contains an electronic fuse which switches off the operating voltage of the amplifier if a set current value is exceeded.
There is also an interface that enables the power supply unit to be shut down with an external switching voltage; this is e.g. used by the DC-Protection.



The output transistors are sitting quite close together and have no heat sinks; with convection only they don't get rid of their heat, so a fan is required. Here, however, a very low air flow is sufficient, so that no annoyingly loud, powerful fan is necessary.


So the amplifier can continuously deliver 30 watts into 4 ohms (per channel) without unhealthy heating.
If someone misses the obligatory small coil at the output: it will later be on the DC protection board; but at the moment the Amp works without it, no problems.
Everything is fitted onto a PVC plate for the function test. The next goal is to make a suitable housing. And, consequently, to replace the SOT-93 series transistors in the power supply unit with the extra board with TO39 transistors.

Here are some more photos and oscillograms.



output board assembly:
the resistors for the output transistors are fitted to the downside of the board.
after every new fitted transistor was tested, if they all work as one

(There are 7 PNPs, 8 NPNs on the main board, 20 PNP / NPNs each on the output board, a total of 55 transistors, per channel)


sinus 1000 Hz .......................sinus clipping 1000 Hz............rectangle 1000 Hz..................triangle 10000 Hz
(each with probe head 10:1)


-> this project on my own page, in german

Amp: Audio Research D70 MkII

Background: I have been attempting to identify and replace resistors that are causing fuzzy output distortion. I have also disconnected the 16 and 4 ohm outputs, and wired a pair of modern binding posts to the 8 and 0 ohm outputs.

I discovered that somehow, the amp is now producing an upward curve starting around 1k and peaking at +4 dB at ~18k (see attached measurements, both channels). I have verified that this is not a problem with my measuring equipment by testing another amp. I'm taking measurements with a 7.5 ohm load resistor at 1v output level.

My first thought was that I screwed up a resistor value, but I've been careful about that, and I'm not necessarily replacing matching resistors on both channels if only one seemed bad, so how would I get identical behavior on both channels?

Second thought is that someone I crossed wires from the output transformer and created this effect? But I'm not sure how that would even work.

I'm on the verge of throwing it at my tech and having him pull my *** out of the fire, but I'd at least like to try fixing whatever I've done....

Hey all,

New member here about to take on a TD160 restoration project. I've scoured across the site and internet and have not found proper plans or dimensions for a new plinth.

I could take apart my TD160 and measure and all that but my wife's uncle is a woodworker and would enjoy building a new plinth but I would have to send him the dimensions/plans as he lives several hours away.

Any leads to help a guy out?

Thanks in advance.

I recently purchased an Allen&Heath Zed-14 for a price that was too good to refuse. There is one thing about it that is a total non-starter for me, the pre-fade Auxes are Post EQ and Post insert. Given the lower price point of this model there are no internal jumpers to configure the options on these auxes. So, off to the service manuals.

I have a plan that needs a bit of critiquing. I have included the schematic for the Mixwizard set up for pre-eq aux, and traced the signal path.
I have also included the Zed, highlighted the stock signal pat,h and circled the components that see audio in red for stock, blue for modifications. There's a blue "X" where I plan to place the cut and a blue line where I plan to tap. My main concern is that when the highpass is not engaged, there appears to be no 47K pull-down resistor for C18.

Thoughts?
Chad

Hi guys,
I’m trying to troubleshoot a noise issue in a digital reverb circuit that’s driving me nuts. Here’s the schematic. Hope you could
Give some advice, I don’t own an oscilloscope and this makes troubleshooting a pain.

I was able to trace down the noise to ADC U201 SDOUT. When shorted to ground, U202 DIN is also grounded and the noise stops.
Grounding U201 /RST resets U201 U202 and U203 and the noise goes away while grounded, but reappears once /RST is high again.
Grounding U201 AINL does not eliminate the noise , therefore I thought the problem was isolated to U201. Replaced it with another cs5340, but no luck. Also thought about this being a problem with the supervisor circuit u205, and replaced the stc809 with a mpc809t but still no luck.
Any ideas??
Thank you very much,
Fran

Setting up a system I will use for a small festival I arrange annually, and have been thinking a bit about the power situation. Typically I will rent a 20-40kVA trailer but both the cost and efficiency is not that great.
As I understand when it comes to generator power you can not treat it as a normal outlet where if for example you have a outlet that is fused at 16A, you will have excess power for peaks on top of that. So that is why for example my sub amp, a Morin x-1304 rated to output up to 4x7380w, can be connected with a regular schuko plug. The average consumption will be about 1/8 of the peak assuming a crest factor of 9dB and pushing it just into clip, resulting in a actual draw of 3690w. Surely it is pushing it to run the amp att full load on all channels in 2 ohm, but in theory possible.
Now with a generator you will not have the extra peak capacity. If the generator can deliver 20kVA that is typically some 5-7kW per phase, leaving very little headroom.
The 40KvA trailer is great and provides really nice stable power and gives resonable headroom, but it does cost quite a bit to rent and run.

So, the frustrating part is that it seems like in reality I would not need such a large generator. If I just had enough capacitance, it only needs to provide enough for the average consumption. So for example with my current system the speakers are rated to around 10500W RMS. Assuming extremely compressed music with a 6dB crest that gives 5250w draw. In reality I would probably be down a DB or so from max and normally play music with 7-8dB crest, giving around 2625w actual draw.
So rather than renting a machine that delivers many times more than I need, can I not add a buffer between generator and amps to handle the peaks and instead run a much smaller generator?

Perhaps a large inverter generator like a 7kW Honda will actually provide enough peak power, but seems to only exists single phase versions, do get very expensive and hard to find for rental in the area.

One solution would be an online double conversion UPS. Those used to be very expensive, especially if they should be able to handle these kind of power levels, but looking at Alibaba there are some units below €1000 with shipping that can deliver over 10kW on 3 phases with a 3:1 crest factor according to the specs. Add some €500 LifeoPO4 cells having great capacity for momentary discharge, and it seems like I could build a little wagon to act as buffer between generator and system ensuring smooth constant sine wave output with greatly increased peak capacity.

So add to that an old 3-phase 10kVA diesel for €500 or so, and then for around €2000 total have something that I would think will beat the €5000 Honda by far when it comes to how much peak power it can deliver.

I'm not that knowledgeable about electricity, and especially high voltage 3 phase, but seems quite doable with off the shelves products not requiring any expert knowledge, but can ask an electrician for advice if needed.

Is it a bad idea, and have I made any miscalculations or incorrect assumptions?

I have been wondering if a din rail/smps is a good option for an audio power supply. One that I have been looking at for 24 VDC output is the SDR series by Meanwell. The noise is a repectable 100mv @20MHz and with a filter should be able to be reduced. Is there any negatives with using a din rail system for audio? This is the link I was looking at https://www.bravoelectro.com/sdr-120-24.html
Thanks for comments.
MM

I have a working volume control made on NE 5532 chips for sale. the price is $50 + shipping costs
made on the basis of the project: https://www.audiostereo.pl/topic/138246-level-controler-aktywna-regulacja-głośności-projekt-diy/

So it seems pretty well-established at this point that a parallel LCR in series with a driver (as opposed to a series LCR in parallel with a driver) can function to suppress any extra HD from the increased sensitivity around breakup (and, I guess, HD-driven IMD too).

But, can a typical passive low-pass filter do the exact same thing, e.g. 2nd order LR or 4th order LR, as long as the slope starts early enough that there is significant attenuation around the peak?