Hey All,

After extensive research, talking to engineering nerd friends, and general hair-pulling, I'm here for advice.

My project is a standalone, 8-channel (octophonic) sound source; audio read from files stored internally or read off a disk.
Signal path is: WAV from flash memory->8-channel DAC->8 channels of amplification->speakers
Essentially, user presses a button to play, and controls gain of four stereo pairs that play in sync.

I have seen an 8-channel player on the market, used mainly for art installations, that looks just like what I'm trying to do in terms of DAC. It's called a Waveplayer8: http://www.waveplayer-systems.com/
I'm guessing the quality with that isn't great, but the quality for this project doesn't have to be, either. I'm fine with 16-bit sound. While I could just try to track one down, I'd much prefer making something more customized and understanding the signal flow.

I'm guessing there are projects like this out there, but I've been unable to find them.

Starting really small, with about 3w per channel, I'm looking at something like this:

1. Power supply:

• AC-to-DC power supply
• Voltage regulator

1. Microcontroller:

• ADAU1452 digital signal processor with integrated sigma-delta DACs (one per channel)
• Crystal oscillator for generating the master clock signal for the DSP
• I2C interface for communication with external devices, such as an SD card reader

1. Memory storage:

• SD card slot for storing the 8-channel sound file
• Voltage level shifter to convert the 3.3V I/O signals of the SD card to the 5V logic level of the ADAU1452
• Pull-up resistors for the I2C interface

1. Audio output:

• 8 output buffers with a gain of 1 (one per channel)
• Output coupling capacitors to remove DC offset from the signal
• Output connectors to connect the analog signals to the amplifiers/speakers

For context, this is my first time building anything more complicated than a condenser mic. Any advice would be very much appreciated, large or small.

Friends,
I have finished the design of the soft start scheme for my dual mono amplifier Q17, where 2x 500W toroidal transformers will be used. The main switch will be on the rear panel.



If you see any bugs or room for improvement, ...

Hi folks,

Looking for ideas on the following.
I want to build a desktop system and envisage a pair of powered speakers to minimise wires, connections, enclosures etc. The main heatsink limits me to about 35W of heat so the choke loaded Mofo seems like a good/efficient choice. So assuming a 24V supply, I would be looking at ~1.5A through the MoFo. I anticipate a power supply capable of providing 3A to leave some headroom.
I plan on using the DIY FE2022 and want to build in some voltage headroom here too.
So the question is the power supply...
I could use two Meanwell SMPS supplies on each side to give 24VDC for the Mofo and 36 or 48V for the DIY FE2022. But I hope that there might be a more elegant solution that is relatively cheap and Noobie friendly to generate low power 30-48V for the preamp from the MoFo supply. In an ideal world I'd like to run the whole lot from a 24v laptop supply or similar. I'd really like just the RCA and power cable going into the box and not mess with mains AC.
So the question is how to get enough voltage swing from the front end/power supply.
As always, your thoughts and guidance are appreciate,
TIA.

I'm working on restoring a Bose 1801. I've replaced electrolytic caps, opamp, carbon comp resistors, main caps, and added DC protection.

I'm having a stability issue in one channel. This is shown in the pictures. It starts happening at very low power. I was talking to Leestereo and he suggested playing with the value of the phase capacitor C8. It is 200pf originally. Raising it made things way worse but lowering it to 100pf solved the issue but destroyed the square wave performance. I don't have any values between 100 and 200 on hand. I tried a new 200pf cap and it had the same issue as the original.
I've had this issue 2 other times and one time I had to raise the value of the VAS cap. The other time it was the resistor in the output network, I don't know what it is called. R47 does that job in this amp.

I've attached the schematic.

My amp that I built years ago periodically crackles or makes other noises. I want to open it up and touch up the soldering.

It would be fun to upgrade or change since I am in doing the work. Any ideas with instruction would be helpful. Any ideas on things to check would be great also.

Thanks.

https://linhkienloadai.vn/blogs/du-an-loa

right on the end-speaker projects


https://translate.google.com/

'Barevids' Sam on Youtube is doing an interesting video series where scaled-down 2" micro-subwoofers get 3D printed and testing inside a model automobile, to compare different enclosures. The fun part (IMO) is that when filmed at a high frame rate with sped up real-world music, the final videos can be played back slowed down by 6x, and they look and sound exactly like a 12" subwoofer playing normal bass.

Testing is done at 4 frequencies (power or excursion limited, determined separately for each tone), 150hz, 198hz, 270hz, and 360hz (corresponding to scaled frequencies of 25hz, 33hz, 45hz, and 60hz).

At this time none of the submissions take advantage of boost the output of both sides of the cone (e.g. 6th order bandpass), they are all either reflex variants or 4th order bandpass as far as I can tell (one seems to be BP4 with horn loading on the output). So I designed and submitted a simple 6th order parallel bandpass and it may get shown! Here is the bulk of my submission:

I've designed a a large 6th order parallel bandpass box using winISD and Sketchup. I am using Sketchup Make 2017, which I had assumed was 'v17', but didn't see any way to export to STL. DAE and SKP are attached. Happy to save to older versions of Sketchup if needed, or download an older version that can export STL.

It's designed to be as loud as possible while minimizing excursion across the test bandwidth as much as possible. The back chamber is about 2/3 of a liter tuned to ~155hz, the front chamber is about a half liter tuned to ~360hz. It should perform very much like a vented box made of just the back part for the lowest two notes; no excursion problems at 150hz, possible excursion problems at 198hz (exactly the same as my best effort basic vented box design, fwiw). Then it should start getting some boost at 270hz from the front resonator, then get a massive boost at 360hz. Attached winISD graphs are shown at 10 watts.

Outside dimensions are 182mm x 108mm x 78mm, with 4mm walls. By definition it has to be a two part box; one end is the access panel panel which should slide in nice and tight. Its double thick since it isn't easily braced; half of it is designed to slide inside the main box. I don't know how to seal it such that it will still be removable! I also don't know how hard it will be to secure the woofer in place inside the box, and I didn't put in any reinforced points for mounting screws. The magnet is designed to go into the rear chamber (away from you when installing), though the tolerances are probably not tight enough to matter.

I've never worked with a 3d printer before so I don't know if my design is even printable. Everything should be supported from below except the rear chamber port tube, which runs parallel to the bottom without anything under it. Please let me know if I need to redraw that!

Click to expand...

Response:

Hey Chompy! Ahh this looks brilliant! I look forward to doing this one! Ill have a play around with it if needbe in sketchup to get it to print well, i think it looks okay as is but ill have a closer look nearer the time of printing 🙂 Thanks for the submission!
Sam

Click to expand...

I also tried designing a large simple reflex, but it ended up being identical to the back half of the above BP6, with no advantages for these test parameters (size isn't penalized for example) so I didn't submit it. Conceptually I think it could be interesting to print a BP6 as a complete vented box with a separate front resonator, and test it both before and after attaching the front part.
I'm fully aware that the inaccuracies of winISD, the scale of this project, and my lack of 3D materials experience may make the entire design a joke; I'm very curious to see the impedance plot of the finished print if it gets used, to see if it correlates. I put some effort into determining the inside volumes of the chambers minus the port tubes before drawing up the enclosure, but the bracing is not really accounted for nor was any end correction made on the lengths of the ports (though the 'middle of the wall' ends should match reasonably with the winISD 0.732 default). Being a 3d print there's no excuse for the ports to not be flared, all edges rounded over, the bracing much fancier, etc, but I'm at the limits of my sketchup skills as it is...

Questions, thoughts? Anyone else want to try? Feel free to post it here if you do!

Here are the test and woofer parameters: https://docs.google.com/document/d/13YayzCsIZ58GIl6czQCEoz9ShTWKgAfU_1n6SGTBByo/

Intro video: Login to view embedded media
Video for how to submit: Login to view embedded media
Episode 1: Login to view embedded media Episode 2: Login to view embedded media Episode 3: Login to view embedded media Episode 4: https://www.youtube.com/watch?v=y7KKPThsA8U
Episode 5: https://www.youtube.com/watch?v=KSvCiuMgGIo
Episode 6: https://www.youtube.com/watch?v=_ws6HA5aXzk

Hi!

I have old CD player - Maranty CD-40. Actually it is my first CD player. It does not want to play CD's. Cleaning laser did not help.
It does not read disc properly - after long time it was off it did read TOC and displayed track numbers and total timing but it was just for a second.
Usually it is trying to read, making strange noise and nothing. Disc is NOT spinning at all.

YouTube

You can see on this video what is going on.

It seems that electronics is 'confused'. Sometimes even if there is no disc inside it is trying to read and play disc. Can yuu help, please?

I have for sale a pair of Usher 8948a midwoofers, pair of 9950-20 tweeter and crossover for the following project:
https://diyaudio.pl/forum/praktyczn...-4-10-usher-8948a-9950-20-projekt-by-yoshi_80

All items are still sitting in complete loudpseaker which is not in use. Slightly used for 2 years, mainly for classical and jazz music.

Will consider selling in below options:
1. Whole set (woofers, tweeters, crossover) 400EUR
2. All drivers without crossover 350EUR
3. Woofers and tweeters separately - price to be discussed
4. Can even sell whole loudspeaker if anyone interested, but shipping needs to be discussed.

All prices are negotiable, for person interested in whole set I am open for your price proposal, similar for drivers set.

Shipping within EU is free in given prices (normally it costs 30EUR)

Hello,

One of sound filter knobs is brocken in my pioneer receiver. Please review pictures and its size and let me know if someone have one. 1:1 match is not important.

Regards,
Turkel.

Got some files of Goldmund-style Preamp design, based on Mimesis 27 PreAmplifier.
I have transformed the file to Altium format, also ASCI or so.

The Mimesis 27 uses A20 modules as front-end amplification, but in this way, additional A2 PCBs are required,
so the design shown here cancels the modules, directly place the components on mainboard, which I think is more friendly for DIYers, unless you're pursuing 1:1 Clone.

As for power supply, the filtering capacitors adopt axial design, very iconic for this type of Preamp; it's actually capacitance multiplier, 45-0-45 VAC Input.
The Iconic blue-shell axial capacitors: Vishay BC (Philips) 470uF/63V, 1000uF/63V, 021 Long Life series.

Rifa PEG long life series is also my favorites too.

Haven't decided how and what to share, just started the soldering work.

***Notice:
All information, resources are provided AS IS.
The information shared may or may not contains incorrect, inaccurate contents.
The provider have no any obligation to be responsible for any consequent loss.













Feedback capacitor: Nichicon MUSES?









The PCB produced on the basis of file.

I think all of the past/present DAC "topologies" are as follows:

(1) Discrete (R2R, etc. Examples: Soekris, Denafrips, etc)

(2) ASIC (single chip, may also have digital filter inside. Delta-Sigma, Bit-stream/MASH, R2R, DEM, CC, etc. Examples: Philips TDA1541, AD1862, PCM63, AKM 4499, ESS9038)

(3) Firmware (FPGA. Example: Chord)

Other:

Parallel ASIC. Examples: Accuphase "multi-multi" ( 4 parallel PCM 63), diy: tda1543 http://www.diyparadise.com/8x1543dac.html)

Anything missing from this list?

Hi everyone. I’m new but happy to be here. I have a pair of speakers that I have been working slowly at since college. Started in Electrical engineering and then went into ministry instead. The boxes are very large and custom finished. My grandparents paid for the materials and my uncle built the boxes. My grandparents have since passed and my uncle ‘s Parkinson’s is now advanced to the point he cannot do woodworking any longer. All that to say these cabinets have a lot of sentimental value to me.

the components were…what I could afford at the time. I have acquired in the time since 2 dynaudio d-54-af midrange drivers (someone told me these are excellent midranges) and 2 Peerless XT25TG30-04 tweeters which were also recommended.

I have a grant for a bit of time off from ministry (3 weeks) and funding for a renewal project. I would love to finish these With the new tweeters and midrange.

the cabinets are very large, I had a 12 and a 15 mounted on the front of each. I can’t add dividers if necessary.

what I need is help with woofer and crossover recommendations. I use a Yamaha 150 watt amp. What I want are to make these the feature pieces of a stereo music system. I want as much range as possible, to be able to play them without needing a sub. I want them to sound good and cover a full range so I can enjoy not only the look and the memories but also the music. I see Madisound has faital pro 15” woofers on sale. would those work?

really looking for woofer advice and tips. Thank you all for being willing to help!

Last items I have remaining out of the FirstOne bundles I have sold recently.

1x Spare FirstOne Large Module (Used) v1.4. £110 (firm)+P&P
1x Hypex SMPS3kA400 2 x 65 VDC 3000w power supply and wiring loom - very little use only around 12 hrs on it. £150 (or nearest offer)+P&P

Items will be available from here until they're sold. UK buyers preferred, but happy to ship anywhere.

Suitable for replacements, or could be used together to power a high fidelity subwoofer.

Thanks.

I have a daughter with good ears and an interest in good sound. We have built a couple of Nelson Pass amplifiers (ACA, ACA Redux and M2) and will continue to explore this aspect, but I am interested in building a pair of desktop speakers that would use a ribbon in open baffle and a woofer in an enclosure or SLOB. Can anyone point me to such designs or threads or make other recommendations?
Many thanks in advance

Am I the only one who thinks linked amps should be called primary and secondary or main and auxiliary? Master and slave feels inappropriate to me.

Hello,
I made a small guitar headphone amplifier powered by a ac to dc 9v psu.
It is noisy but it goes silent when I connect neutral to ground outlet pin.

I know it is not safe to do so, but at only 9v ?

Thanks

I have an opportunity to purchase up to 30 pairs of TOSHIBA 2SK1530 & 2SJ201 MOSFET's. They are NOT matched and the price from Tokyo is $60/pair. They are only available as pairs of 2SK1530 & 2SJ201. This is the best price I could find in Tokyo, others wanted $40 - 140 each piece, so $60 a pair still seems high to me.
I don't need nor want 30 pairs, so I thought others might be interested. The price including shipping and PayPal fees from Tokyo to Wisconsin, USA. I would like to keep the group buy only for North America as I've had such problems shipping to G.B. and Europe.
If interested reply to this thread, I'm not overly excited about this purchase due to the cost, so I would gladly join the little to no interest group. However, if there is a demand, then I will put this together.

I’m putting together a hybrid OB / horn speaker. I have 8 x AE Dipole 12 woofers to play with, so 4 per side. Current plan for them is a 1.5 arrangement whereby 2 of them are low passed at 100hz, whereas the other 2 are low passed at c. 600hz. This post concerns the 100hz low pass ones. I am thinking I might put each one in a U frame. Alternatively I could put 2 in a SLOB with wings, similar to the configuration XRK used on his XSD speakers.

I’d welcome any thoughts or comments from the OB cognoscenti on the relative merits / disadvantages of these options, or indeed any other suggestions.

I have a little problem finding the right Magnetic Hydraulic breaker to a couple of Threshold 4000's from -78 and -79.
I have already done a full restoration of blown OPS, but those breakers (that have failed afterwards) seems to be some crappy ones that doesn't live longer than 35 years 😉

Does anyone know specs to look for, or do you know where to find the right ones?

Best regards

Figge

Have here a nice and cheap pair of GRS 8FR-8 drivers and like to put them in a simple cabinet.

Data sheet GRS 8FR-8:

Resonant frequency fS 39 Hz
Electrical Q QES 0.46
Mechanical Q QMS 2.94
Total Q factor QTS 0.40
Suspension equivalent air volume VAS 64 litres
DC resistance RE 7.02 Ω
Voice coil inductance LE 1.28 mH
Maximum linear excursion Xmax ± 3 mm
Efficiency η₀ 0.81 %
Efficiency bandwidth product EBP 84
Overall diameter 203.2 mm
Baffle hole diameter 184.1 mm
Mounting depth 98.4 mm
Diaphragm material Paper
Voice coil diameter 38.1 mm
Magnet Ferrite


Proposal:

There is a long running and popular thread on Distributed Mode Loudspeakers started by @xrk971 which you can find here https://www.diyaudio.com/community/threads/a-study-of-dmls-as-a-full-range-speaker.272576/

I have learnt a lot from all the contributors to this thread and have built a number of successful DML’s. Its a very interesting technology that gives great results for not a lot of money which is one of the reasons its been popular on this forum.

This thread is best seen as a stub of the DML thread exploring exciter design. There are many exciters available commercially and they are relatively cheap compared to other loudspeaker drivers so why should we bother looking at DIY options? Same as any other AudioDIY project, to see if it is possible to build cost effective alternatives to commercial designs and, especially in this case, to explore new ideas, push the state of the art and, explore options not available to commercial manufacturers.

Commercial exciter design is targeted at the mass market and so engineering costs are constrained by what the market will bare. All commercial products have to absorb a lot of costs that don’t apply to DIY designs. Take away profit margins, distribution costs, marketing expenses, and some of the engineering costs targeting presentation rather than performance and the amount of money dedicated to sound engineering (sorry!) is less than 50% of the purchase price and for some components can be a lot less.

In the next three posts I will outline each of the areas I am looking at and then, as time goes by, post the results of experiments as they happen. All contributions and questions are warmly welcome as always, but if I end up talking to myself that’s cool to, I do that a lot.


Burnt

I have a very good album of Chet Baker. Called 'Embraceable You'.
He was a trumpeter.
But he also did some good singing.
Unfortunetly he was a drugist. He died too soon.

Do you know some other artist(s) that take drugs?

Hello,
I have a Quest QM215FR dual 15” with 1.5” HF.
The speaker is a 3-way quasi design (specs attached) with the upper 15” speaker operating as a midrange extension. The cabinet has both LF and MID driver rear cone open to each other, No baffle. From the specs the LF to mid crosses at 400Hz and from mid to HF crosses at 1.6Khz.

The crossover is somewhat huge. Large inductors. The LF has a second order Lowpass with the mid a having a bandpass second order. HF has a high pass with attenuation network of resisters. No bulb protection. Simple as it gets however, there is an additional rather large LCR series network across the LF speaker acting like a band stop filter or to remove a resonant peak from the sub LF?

I like to remove the x-over altogether and operate the speaker with a 3-channel plate module. LF/MF/HF an Amp driving each speaker.

Has anyone configured a crossover curve to work with quasi 3-way using the Mid LF quasi principal of extending the mid range to 1.6K without effecting the Sun LF response? I’m not sure about what I need to do with this LCR across the LF for best performance? Guessing it’s purpose is to dampen the peak in impedance at free air resonance? I could be wrong. Or is it to improve the mid LF influenced by the low LF?
Both Low LF and Mid are the same speaker eminence 15” driver bass/mid speaker.

Anyone delt with this type of design have any tips for configuring?
Any advice appreciated.

Rob

What is the simplest way to make a circuit that will allow AC or DC voltage to pass UP TO a value that you set or specify, with decent millivolt accuracy in terms of the voltage limiting feature?

Considerations

• When the limit voltage is reached, the circuit should continue to allow voltage equal to limit value to pass (it must not cut it to zero).
• If necessary to choose between AC or DC, then AC would be preferred.
• The circuit will should have four connection points, two "input" which can be 0-35V (ac or dc; input range can be adjusted to make it work), and two "output" ports
• The output must pass from 0.01 mV up to the voltage limit set.
• If input was AC output must be AC; if input was DC then output should also be DC.
• Ideally, the circuit should be passive and should not require power to operate.
• Should be able to handle at least 100 mAh of current.

happy new year every one !!!🙂

This thread is a actually a copy of an existing thread in a Greek forum .Obviously the thread is there to inform and attract costumers and actually working very well .

I presume that there is no point on placing a similar thread in the diyaudio to attract costumers but still articles comments and photos are nice to see and read for every one .

i would like to welcome any forum members if support schematic or any kind of help is needed and i will be more than happy to provide. Don't expect e mail in 2 minutes but i ll do my best to answer as fast is possible .

Most of those amps i keep schematics from, that i will be very happy to share and also i have very good memory resources about common failure and repair tips ...

enjoy

Hi,

I’m building a 12” fullrange speaker, and I’m a bit confused what is the preferred wayin speaker cabinet design. I’m a mechanical engineer and I have an opportunity to run complex FEA simulations. I had a base design, what looks too flexible, so I started to reinforce it.
I’ve run Steady State Dynamic (Modal) analysis, do check the dynamic behavior of the cabinet. The result is very confusing:
Base design:

• First resonant freq is around 80Hz
• max. normal displacement is 0.1mm
• max. normal acceleration is 8G

Modified design:

• First resonant freq. is around 180Hz
• max normal displacement is 0.03mm
• max normal acceleration is 50G

My guess is that the new design will have less influence to the sound because if the side of the cabinet act like the speaker membrane, and generating sound waves, the amplitude will be much smaller, and the membrane are is also much smaller.

Is this assumption correct?

Adding more reinforcement moving the resonant freq. up, and reducing the “membrane are”.

Another interesting thing is that the displacement of the 2nd and 3rd resonant frequencies much less, so have to focus on the first.

ok folks this ones a bit out there but here goes - ive got tascam 22-2 - i

would like to add the autostop feature from the x10 - and others - im locked

out of vinylengine - so i cant get any info on what parts needed or if its even

possible - i would appreciate it if someone sends a message to vinylengine

giving my email - johnnykojic@hotmail.com - as im locked out, reset

password not working - its happened many times to me - thanks all

I was wondering if someone has already done something like that. Otherwise, gather feedback.

So summer is coming, cookout and bbq season is around the corner.

It is nice to play some smooth soul while sipping cocktails.

Ive been having this idea of buiding cheapish set of speakers using an somewhat efficient full range and power it using some chi-fi stereo bluetooth module. Up to 10w would be plenty I believe.

Thinking about bass reflex, visaton bg20 that have 92 something sensitivity. The cabinets would be pretty big I belive, around 60 liters to go down as low as Fs 38hz , right? Would put them on wheels. Sensitivity would drop a bit as they would be placed outside no walls - need bsc.

Power would come from a battery.

Has anyone done a design like that?

Big Hypex UcD Clearance.

They have been used just for testing when calculating crossovers. 50/60 hours used.

Set 1: Hypex UcD180_HxR + Hypex SMPS 400/180 (4 sets available. PVP 228€, asking 110€ each set)

Set 2: Hypex UcD400_HxR + Hypex SMPS 400/400 NO LONGER FOR SALE. I WILL KEEP THEM.

I will only sell for sets (1 UcD + 1 paired SMPS) unless you ask for a lot.
PP fees and shipping not included.

Verry little used, some good two months old in perfect condition. Nice output trans for 300b,2a3 or other tubes. This is 90mA version. Price 350 euro plus 16,90 euro shipping inside EU.They cost me almost 600 eu with shipping from Don Audio Germany! Payment by paypal for friends.

Matched pair, produced in 2020,I buy this last year but have only used this for about 20 hours. Tubes like new in original package. Price 300 eu or best offer. Shipping inside EU 12,50 euro. Payment thru paypal for friends.

For sale hammond chokes from 19x series.
One pair 193j and one pair 193h.All together 150eu plus 22,90 euro shipping inside EU. Payment by paypal for friends. This are like new.

Hi all,
Does anyone think that old school 12v 10amp plus "car" battery charger transformers are good for anything?

Jeremy

Hello
Does anyone know of a usb sound card that has a digital input. It also needs to be linux compatible and not very expensive.
Help appreciated.
Thanks
thyristor44

https://www.bugamps.com/ no affiliation. Just sharing. Not on their website yet...but on his facebook page.

Hello,

My receiver have 2 antenna ports, as usual in all receivers)))
1) AM Loop
2) FM Unbal 75om

I have one antenna - AM loop only. Can I connect it to FM port? Actually when I connect it works OK but it may also damage tuner or reception of rf may not be high quality. Please Advise.


Regards,
Turkel

hi - im using the above - all line ins ok but no phono- are there different types of card for MM etc?

I have gradually being buying materials to build the Honey Badger amp, but due to various reason I have stopped for about 2 years. On April 2021 I bought CDE 380LX filter caps (16 of them) and have stored them in a dry room-temp place. I believe I will complete the project next year, so they will have stayed unused for 3 years. Will they have gone terribly bad until then? Is there anything I can do to save them? Maybe charge-discharge each one a few times?

Sold

I have 31 NOS pieces Valvo D3A tubes in original boxes, 5 boxes have small defects. I intend to sell a lot of five tubes for €110 but if you want more let me know. Tubes cannot be matched. The price does not include shipping costs. PayPal accepted, registered shipping plus 5% PayPal fees. With PayPal Freund, the 5% does not apply and can be sent without tracking, shipping with a tracking number costs around €17.99 within the EU, depending on the package size. Within Germany without insurance with shipment tracking as S packaging approx. 7 €. Shipping within Germany only this week until Thursday. Outside the EU it may vary by country and need to be checked with DHL

Some speaker crossover parts.
2 x 0,33mH copper paper in wax
2 x 0,12mH copper paper in wax
2 x 2,70mH copper foil feritte
2 x 22uF obbligato pio caps
Price for all would be 40 euro plus 17,90 euro shipping inside EU. Payment by paypal for friends.

After 32 years, Hi-Fi World magazine has ceased publication. The company producing it has became financially unviable due to loss of bookstand sales in the High Street and at railway stations and airports around the world during the Covid Pandemic.

I've been a long time subscriber and will be sad to see it go as it was the closest Hi-Fi magazine I know to a hobbyist publication.

Unfortunately, the September 2022 issue was destined to be the last.

The magazine was the work of a lifetime for the editor and publisher, Noel Keywood and I wish him and all those associated with the magazine all the best for the future.

Some members may remember Hi-Fi World's excellent DIY Supplements (see attachments).

I've been thinking....Dangerous I know! On another forum a fellow was reporting that he was using a Portable Power Supply (A LiPo battery in a box with a Pure Sine Wave Inverter) to power his system. He suggested that it got him totally away from the "Grid" and all its noise and distortion. I've done a lot of work and built a number of these +Solar Generators" for the Overlanding RV crowd and I know the best of the best still has issues with the inverter phase of the operation when used with delicate electronic equipment. This morning I'm reading a review in Stereophile about the "FE - HYPSOS"....A stand alone power supply to be used in place of supplied outboard power supplies. Very interesting article, BTW. So...I was thinking, with Li battery technology exploding as to amp-hours and limited voltage drop over its discharge cycle, would it be practical to build HiFi equipment that runs on 12, 24 or 48V DC and do away with the whole AC to DC conversion in the equipment. You would charge up your LiPo battery at night from the grid, or during the day while at work off solar, and run your system for hours when needed. Pure, Clean, Voltage stable DC power...No grid connection during play. Wouldn't this drastically reduce the cost of components if they didn't need elaborate power supply filtering etc? LiPo batteries are relatively light weight, have huge amperage discharge available and have life spans of 20+ years with the ability to be recharged thousands of times. Current Lithium batteries don't catch on fire like older batteries did...So don't go there. One LiPo power supply unit could run the entire system rather than multiple power supplies in each unit. Yes-No.....Go back to bed?

I'm looking at it as not only a noise/performance issue (as many folks have really horrible grid electricity or live in apartments with outdated infrastructure)......But also as a manufacturing cost savings and weight saving for shipping. No heavy toroidal transformer and extra heat sinks. Shipping cost have become a huge part of the cost of manufactured goods.

Selling 24 pieces of MIC29502WT LDO Voltage Regulator 5.0. I used these for Tube heather circuits as well as in my Aikido OTL Tube headphone amp that I bought from hvforless the boards on eBay. Ask 6€ for a piece. The price does not include shipping costs. I don’t need them anymore, PayPal is accepted, registered mail order company pays the additional 5% PayPal fees. With PayPal Freund the 5% does not apply and can be sent without tracking, the shipping with tracking number costs within the EU are approx. 13,99€, without insurance and tracking as XS packed 6€ . Shipping within Germany €6, but only this week until Thursday. Outside the EU it may vary by country. I can combine shipping. If you are interested send me a PM.

Hello

I have an opportunity to buy 7 pcs of the famous 6c33c, but there are from different batches/years of production. Is this important? There will be used in a future SE amplifier.

TWTMC-DBM-F 5.6448 MHz to 11.2896 MHz
New Frequency doubler 5.6448 MHz to 11.2896 MHz

$150 shipped in the US - this was the last one Andrea had when I bought it.

Hello community,
As far as I know, there is a relationship in the throw distance and low frequency development, so I ask those who have used EMS drivers, which will be suitable for a room that is only 3 meters. That is, if we subtract the chair in front of the equipment, the listening position (ears) would subtract about 30 cm from the throw distance, before reflecting the sound on the wall behind. This means that my listening point, given that the speakers will eventually not be butting up against the front wall, could be between near-field and mid-field, at about 2.3 meters or less.

Of course it's always preferable to have the widest extension, so I originally thought of the LB12MKII, but I'm pretty sure a larger spacing is needed. So the next best candidate in terms of extension was the LB8MKII.
Now I've been looking at the LB8MKII, LB7MKII and LB6MKII drivers, with the first one being the lowest in frequency range of course, but given the limitations, does anyone know which would be the most suitable for this space?
Btw, I'm using a 300B SET integrated amp (about 7 watts).
Looking forward.

Looks like the ransomware gang the hit royalmail.com did a good job. 12 days later and they still can't ship any international parcels. I think this kind of stuff is only going to get worse - I heard they were asking for £12 million. Unbelievable.

In the meantime, I can't ship anything until the issue is resolved.

😠

Rest in Peace. The Wizard of Foz


Fosgate invented the first car audio amplifier in 1973, with his company; Fosgate Electronics which became Rockford Fosgate.



Millions owe it to him the legacy and legitimacy of aftermarket Car Audio.

https://en.wikipedia.org/wiki/Jim_Fosgate

https://www.tnt-audio.com/intervis/fosgate_e.html

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I have 1:1 isolation transformer(110,220 -110,220) 0.5kW.
Can I use the isolation transformer as a power transformer for a vacuum tube amplifier?
Thanks for your responce.

Most of the Rotels amps RA920/93/932 and later RA 1, 2 etc are reputed to produce a lean bass anf the lack of a loudness does not arrange things. I want to modify the RA932 tone controls. I have compared some older models and found that the resistors and caps values are different, although the Variable potentiometer is 20K. Any engineers or electronic pro can tell me which of the following tone controls will produce a better bass? The first schematicsis that of my Rotel RA932 amp. The 2 others are RA840bx and RA971.

Or a 2SK133 or 2SK134.

I am in the process of modifing my dddac. I will add a buffer and some bether powersupplys. it will also get transformer output. The only thing I miss Is the opurtunity to conect a cd transport to it. I see tentlabs have a spdif in I2s out board. then I would only need to get a board with multiple i2s in and 1 out. Audiophonics has one board like this.

The only problem is tentlabs is out off stock. Do anybody now off some other boards with spdif in?

Hi

I have a situation where I need to delay a pair of B&W DM100i speakers for ~8ms. I have an another set around 3 meters away from the speakers. Is there any way to do it without expensive hardware?

I recently had to replace one of those cheapo stereo B100K pots that china graciously sells in packs of 10+ on amazon. I did not replace it with the same, instead, while looking for an ALPS pot that would fit I stumbled across a "ladder attenuator". For those who don't know, the ladder attenuator is essentially a ~23 position switch that has actual resistors across the poles, such that each "notch" gives you a specific resistance for extremely stable volume control. Mine is 23-step and it fit without a problem even though it takes up a lot more space than the tiny B100K. Obviously I could not mount it directly to my preamp board, so I had solder wire leads to the attenuator, which then soldered to the preamp.

I honestly did not expect there to be much of a difference, but WOW there is a huge difference and in a good way. I don't really know how to put it because this amp already sounded good, but with the ladder attenuator no matter which volume notch it is set to, the sound is impeccably clear and the separation between the stereo channels seems to be a lot more defined and precise. This separation makes sound come across as bigger, with more presence and a "wider" span.

The most noticeable changes happen at lower volume levels. The best way I can describe it is like this: with the regular rotary pot, when the volume is low certain sounds are more prominent than others...so you effectively end up with portions of sound that are inaudible. With the ladder pot, as long as it is set to an audible level ALL sound is audible, even subtle sounds.

So if you are want to do ONE upgrade to your amp that will produce meaningful and beneficial results, try a ladder attenuator. I am using one I got from ebay for about $25 that uses "dale" resistors. They are all over ebay.

What cause this to burn and how to replace it

I accidently destroyed a chip on the board so If you have a board with a bad laser you don't know what to do with it, I could be interested to buy it. Thanks

Hi ... does anyone have a copy of the original Praying Mantis tonearm?
Lost mine long ago. It might be time for a 2023 upgrade after 45 years. Linears have short arms, could work again. I've built two in the past, but were too flimsy.
Zene

Hello everyone, hope this is the correct sub forum.

I’m working on finalizing my plans for the music and tv in our new townhouse’s living room. As commonly seen, I’m designing within the spouse acceptance factor. That being said here’s my perceived options, all active with dayton kabd boards.

I’m currently in the middle of building a 1.1 system with a center consisting of two rs100p-8’s sealed with the dc28f tweet and a Tang Band W5 sealed in .23cf. This would be a benign setup with very modest bass, the small subwoofer will actually have a high shelf filter to have flat response to maybe ~30hz. Of course overall spl will suffer greatly but the lady, and neighbor probably won’t enjoy percussive content after dinnertime, so the design will be low spl flat-ish bass.

With the rather pedestrian 1.1 system, I’d be in need of a small stereo bookshelf pair for personal music listening. This pair would be limited to a set of .23cf cabinets with an anarchy 5.5” sealed, peerless 1.5” fr and 5/8” tweeters. It’s not a very large room but the .5 cf bookshelves I’d like to build would probably be a little big looking.

The last option that I feel is realistic is gutting and restoring an old ~.44cf polk center with dual anarchy 5.5’s, a 1.5” and 5/8”. This option has the ability to be a one speaker system that would be too big if there were other speakers around the room but if sold as the only speaker I want to have, it would be an easy sell.

The main question is whether I should put all my eggs into one basket (gutted polk dual 5.5” center) have what I would consider a pretty nice speaker, or compromise on a small stereo pair and small 1.1 system. Would I even be able to achieve the stereo effect in a small oddly shaped room with small bookshelves close to the wall and one probably kinda in a corner? Because if the speaker placement/size will prevent the stereo effect then wouldn’t it be wiser to just go all in on a good center? Two eq’d anarchy 5.5’s on ~150w model more than enough spl for what I’d realistically ever use. I could program a knob to attenuate bass depending on the time of day.

I appreciate that among amplifiers this is probably the easiest to point to point, however I am trying to package this neatly, so am on the lookout for pcbs...
cheers
edited to add that I am asking for any availability of boards that I would propose to buy. I am not looking for a charitable donation...

Hi,
I finished the PCM 2707 based DAC. The DAC is based on the recommended topology by TI. It works, however it reproduces sound with some very weird distortion, where some of the frequencies got echo. The specific sounds are audible many times with continually decreasing magnitude (with 4-5 audible repetitions). Does anyone have a clue what might be an issue? The sound got the same signature as if I was using old WINDOWS XP sound echo chamber mode. Just to be more specific: I used different USB cables- it did not help, also checked sound settings and all enhancements are disabled. I was not able to find much information about this chip on forum. Some photo attached. Here is a link for the project:
https://hackermagnet.com/usb-dac-pcb-with-pcm2707/

Well, you know I've been on this site for a while and I've had an end game in mind for my stereo system. These days I find myself convalescing to some degree, so things are pretty slow around my house, so I got the time and all the hardware. This project is based on what I think would be the best diy system to play with building active speakers and have the most flexibility when tuning a multichannel active speaker system while still having a way to easily switch back to an everyday system that can run a fully passive system for everyday listening that doesn't consume as much energy.

Recently I was able to horse trade for a dbx 4820, well I don't need to tell you that this is just what I was hoping to base this entire system around. It has direct balanced digital inputs, room correction, a multitude of features for sound contouring and measuring. I guess I could have gone the minindsp way or deqx but these solutions just don't seen as interactive and I just wanted to take another approach.

The only problem with the 4820 is there is no easy and cost effective solution to controlling all the 4820's channels volume simultaneously. It needs to be good quality. What I really need is a serious 6 channel preamp that also has a feature to run a separate amp and speaker system for everyday listening. I scoured that net for something suitable and came up with the Thule PR350. This is a really decent analog preamp, looking a bit more into it reveals that it has a completely seperate digital and analog sections and the seperation between the circuits (for the most part) it controlled by mechanical relays. That sounds like it would be super simple to modify into exactly what I need.

So the features on this preamp that I will use are the direct 6 channel RCA input to control volume on all 6 mono amps powering the active speaker setup and then the preamp also has a feature to have a separate direct XLR in to XLR out with simple buffer and volume to control the passive setup. The opamps are mostly OPA2134. These are excellent quality opamps. The volume control is handled by several lm1972 ic based volume control chips. These are excellent volume control ic's and are still in production today and seen in some seriously high end gear.

So you see how this project is going to play out, I'm not really sure anyone else is going to be interested but for the curious I will post my progress on this thread. The first step is repairing the Thule, it has some blown opamps but the control circuit is in great shape. I've used this preamps direct XLR feature for many years. It is a really high quality direct volume control. The circuit for this feature even has it's own little, highly regulated power supply. It's a beautiful preamp.

Another thing I'm going to do is post lots of nudes of the 4820. I've scoured the net and can't find any and I don't know about you but I love looking at nude photos of gear and I hope this helps others on their quest by making these available.

Hi guys,
I need a good model for a triode suitable for a cathode follower that can swing some 300V pk to pk.
One candidate i have in mind is the PC92 because of the 250V heater to cathode rating.
Does any of you have a model that would work in Circuit Maker (3f4) or could easily get adapted to.
Other suitable suggestions/models are welcome
Thanks,
Pete

I need input buffer for baxandal tone controller. Schematic is given below
Thanks in advance

Nice verry little used pair of chokes. Price 110 euro plus 16,90 euro shipping inside EU. Payment by paypal for friends. This cost new 110eu each by Don Audio Germany.

I was hooking this amp up and like an idiot I wasn’t paying attention and the ground wire hit the positive terminal of the battery bank

It blew 2 traces on the bottom of the board and also took out a couple of power supply fets .

I fixed the traces and I am going to replace the power supply fets and drivers .

Is there anything else I should check to make sure nothing else got shorted ?

The output section seems to be fine
The power supply driver board in the amp is the same clone as all the other big amps

I find this sonogram from Dibirama site very useful. Very informative and understandable how the driver sounds.

What program can export flat sonogram like this?

LM4780TA Diy audio amplifier kit included power supply PCB 44€ more shipment
LM4780TA IC with PCB more power supply PCB with connectors and pré amp pcb.
Tracked shipment,shipment to US on request
Skematics sended together with articles
Payment by paypal

So I mistakenly posted this in solid state. Any ideas?

First time poster (long time lurker 😁)

I’m trying to drive a 3e tpa3255 module with a differential signal from an adau1701 DSP via I2S by feeding a pcm5102 module (the common purple one) with a mono signal on the left channel and the same mono signal (but inverted in the DSP) on the right channel. It seems to work but sometimes when I remove the inversion I can still hear some signal, when I’d expect none (except some noise from slight variations in the output stages). Maybe interference on the I2S?

Anyone tried this? Should it work? Any downsides? Any tips?

Keen to use this approach to keep weight and noise down and quality up in a portable PA party speaker.

Thanks for any help!

I’m intrigued by this newish design from Bert D that appears to be a horn / SLOB hybrid. In particular I’d like to understand the arrangement in the throat area of the woofer array. Any body got any insight into the design?

Hello. I have a pioneer pl 71 down in my basement with speed issues. (runs way fast) One of the 502 potentiometer on the motor PCB is literally falling apart. The metal slider has come off.

Is this 502 pot interchangeable with one of the Chinese made 502 pots available on ebay? Are there better quality components to be found? I've been looking at 5k ohm trimpots at website in my home country, and there are many different kinds ranging from 150mW - 1 W. Is this a important factor?
Could I play around with a multimeter to find the correct rating?
I have been looking at the service manual , but I can't really tell if there's any relevant information there.
As you might have guessed by now, I'm very much a newbie in this field.

While having had the turntable serviced by an vintage audio repair shop, the guy said the whole motor was probably shot and in need of replacement.

I however have a hunch that this 502 pot is the culprit.


Wanted to get some feedback from someone with some experience working on electronics before shopping for multimeters, random parts and soldering tools 😅

Any help is much appreciated.

Hi,

I have an Aiwa DX-666 which will not read CDs. The spindle spins up for about 10 secs then stops, and 99 appears on the display. Everytime I hit 'play' the same thing occurs. The RAFOC unit is a CDM-4/14. With no CD in the drive one can see that the radial arm moves to the innermost position and the lens moves up and down a few times. I have measured the laser current which is 50 - 55 mA, and the eye pattern is about 2 V pk to pk on a scope however this is not a clean pattern (more like a bird's nest) as the spindle stops turning after about 10 secs which is not enough time to adjust the scope trigger etc. I have re-capped all the electrolytics on the servo - preamplifier board except the bipolar one.

I have a Service manual but it is for a CDM-2 so I am not sure if the test procedures and given measurements would apply to the CDM-4. The manual mentions various 'service positions' and how to select these but not service position1; I have not attempted to set these yet. I would be very grateful if anyone could offer any advice. I am not familiar with repairing CD players and to be honest am feeling a bit lost so any help would be great.

Could I also ask if anyone knows where I can download a service manual for the CDM-4.

Many thanks.

I had to buy an isolator from usb ground noises from my puter to my DAC, i decided to buy two,

the IFI AUDIO ISILENCER https://ifi-audio.com/products/isilencer-plus/

and the wisdDenfender https://wiki.wisdpi.com/wisd-audio/wisddefender

My DAC's USB cable is 5m long, pluged on my pc's USB 3.0 back port,

the IFI does half the job removing most of digital noise, but still a lil wind blowing noise at high level at $70

my surprise was the Wisd device, it removed all noise, as if it was a toslink optical device and at around $40 priced, for 3 dongle, usb < usb, usb C< usb, usb c < usb c pack

Sometimes dearer doesn't mean better.

😉

HI, Ive had two of these chips die on me two different boards unexpectedly. Does anyone have a couple theyd part with? Its

XL7015E1 used on TPA3255 boards. Let me know. Im in US. Ty​

I can't figure out the deal with this ps. The wave going into the drive transistors is clean the output is like this.

Good morning, I just recently put together an amp with these amp boards without reading up one the issues they might have. One is oscillation and it was recommended to charge the 1K resistor to 910 ohm one. The AC ripple is near zero on both boards and the DC offset is 6 mv on one board and 10.5 mv on the other. I have not changed the resistir yet.

I have an Leader old analog scope that is 20Mhz with dual trace and a 1khz sine wave is not very steady with the peaks fluttering around and I cannot seem to drive a signal through the other channel.

First of all, I have not used a scope that much, I do, to check power output mostly on the projects I build so I can provide details to a potential buyer but I need some advice on checking for other issues. I always put in speaker protection and make sure there is a Zobel network and a Thiele networks as well to quell most issues. I do not want to have someones speakers burn out because of an amp issue. Is there a proper procedure to check for oscillation on a scope and what does it appear like on the screen. ?

Any advice would be helpful. I have hooked up my old test speakers and the sound is good, but the balance seems off a tiny bit, could be my preamp or my ears as well.!

Thanks Wayne

I heard a speaker yesterday that had superb tight and tuneful (multi-note) bass. It utilised 2 of these 15” woofers per side and the following information was provided in the blurb; reinforced paper diaphragms, 800W power handling, 4.5” voice coil, aluminium demodulation ring, twin spider suspension, ferite motor and +/- 14mm excursion. Sensitivity must be in the 90s. Here are some photos:




Anybody know what these woofers are?

Hi - looking to replace surrounds on Tannoy Arden mk1.

I see a very complicated process posted on utube recommending using voltage to raise cones etc - though also note some of his difficulty was due to having non-notched surrounds, making it very difficult to navigate round the cone reinforcements.

I have reconed quite a few drivers easily using common sense and general practical skill (regular simple woodwork projects and model aircraft on a basic level).

So;
Without using specialist equipment mentioned , and with the experince above; how do folk rate the Tannoys in difficulty - is it easy to imagine me accomplishing the re-surround or are the SGM-15 drivers a league to far in anyoine's opinion.

I notice the foams on mine appear to go underneath the reinforcements - N.B. I know this speaker had a recone early 90s at the Tannoy factory.

Any bits of advice etc welcome.

thanks.