Hi everyone


Trying to troubleshoot my Orion HP 4800. It powers on and works however the rear ch3/4 speaker output is very low. Gain has to be turned up almost all the way and even then it is very hushed. I assume it is some sort of fault.

When connecting the 3/4 channel to 1/2 channel, speakers play nice and loud. Seems that the 3/4 channel output has some fault

ESP light is constantly on.

Any advice would be appreciated.

Hello,

Is someone aware of a brand tool to measure the inductance of our loudspeakers passive coils that is precise enough for the task to be usefull while not costing too much, please ?

I have not the monney for an expensive one nore I have an extensive need in the future but few loudspeakers refurbishing and one or two diy. I do not want either to purchase something that is not usefull because not precise enough for the job.

Well I am in europe so I surmise less choice than China and USA and btw shippment became expensive too. While Amazone warehouse have stocks in Europe.

Which unit to buy cheap and good enough ? Or the minimum items needed in the tool description to be able to chose one ?

I have also the jigg for Arta but I am not sure it is possible to measure the inductance without too much complex math for me.

Many thanks

Hi, I'm wondering if a subwoofer made of kevlar with carbon (hybrid fiber) is any good.

Kevlar or aramid fiber has very high stiffness but little damping whereas carbon fiber has better damping but less stiffness.

So, would a hybrid fiber that has aramid and carbon in its composition have the advantages of each of the materials?

When I say hybrid fiber, I mean the two materials intertwined in a single structure, different from a cone made with carbon at the top and Kevlar at the bottom.

The picture below is a fabric made from Aramid and Carbon Fiber, as I said.

A friend of me is a audiophile. He has a luxman SQN150. If I look at the specs, I see 2x ECC83 and 4x EL84, so this must be a PP circuit,
His last investment was to replace the standard 5x20 fuse with a "special" fuse bought at a dutch hifi shop. He claims that he can hear a significant difference. At the (dutch)website where they sell this stuff there is a description wich made me laugh: " these fuses have the latest innovation on passive Quantum Inductive coupling. After the specific conditioning process followed by a signal of 1.000000 Volt called quantum tunneling it is causing the conducting channels within the special melting wire to change. After that theÿ add a quantum inductive surface wich contains graphene ( carbon of one atom layer in a hexagonal structure) to stabilize the electrical wave which feeds the system.

Wow, that sound cool. Price for this item varies from 75 -200 euro's (!). that sounds like ******** to me. I made several tube amps for friends of me and use good components within the design like metal film resistors, oil filled capacitors and good output transformers like Lundahl or toroid ones; that's worth it. But, a fuse wich is only is between the mains ac input and the (toroid) power transformer followed by a tube rectifier and classic R/C/L circuit cannot ( to my opinion) make a difference.

Comments please !
Erik

Hey,

I've just bought a second hand krell kps20i and i'm looking for some info on this machine as it has a few possible problems.

First, the player makes quite a bit of noise when the disc is spinning, eg not what i'd call quiet anyway.

second is that i seems to produce quite a bit of heat on the left side when running, i guess this is the psu area...

Other thing is the lcd display is not working correctly (time display i think) some of the characters are broken, i guess this is a fault..

Are any of these things (apart from the LCD) "normal" for the kps20i ?

Thanks

Reuben

Yes I did do multiple searches. On this forum and others.
Here is a picture of what they look like. 5 legs with one leg cut off.
I have access to these in numbers and would like to use them in my audio citcuits. Has anybody else done this.
Has anybody got a data sheet or a schematic which uses them ?.

I was wondering where the paterns best match. 1400? The Beyma is the one in the 80x30 waveguide. I assume the narrower patter lets the AE run a bit higher than with a SEOS 12/15 and a compression driver. Where has the TD12m been used to with a SEOS15 or SEOS12?

Thanks in advance

Its been a while but Hi to all.
I may have been completely stupid here (?) but I've recent decided to go back to my past HiFi amplifier love and purchased a Meridian 101b & 105 (the 105s casings as a bit rough but apparently fully working). However, having looked at the the 105's, the power supplies are 103.5!! Is this correct???

Many thanks
Rob

I am planning on making a speaker with all 8 ohm drivers, tweeters, 5 1/2" mid, 8" woofer. I'm thinking of just wiring them all in parallel and using a high pass capacitor to step the signal from low to high. Will this work? Is there something I need to consider when doing this kind of design? I absolutely don't want to get into modelling x-overs or building a fancy 3 way x-over, I realllly want to keep it stupidly simple and just tweak the roll off points and be done.

I am looking for a bass-reflex enclosure frequency response formula for plotting a curve in a calculator program I am making as a course project. Can anyone give me any leads to where I can find that formula? I tried this :

http://homeswinghome.free.fr/audioreceipes/bassreflex.htm

but it doesn't seem to work. Am I doing something wrong?

2n3440 npn or 2n5415 pnp are low noise transistors. They are used in old vintage amplifiers but they sound well enough but now a days they are very hard to find.i want to replace 2n3440 with new type of transistors is there any modern transistors that can get close to these transistors?
Is there any possibility to replace 2n3440 transistor with today's modern transistors??

For sale a pair of Ghentaudio STEREO aluminium cases with Neutrik inputs.
They had installed some amps but in perfect condition.

Valid for Nilai, UcD, Ncore, NcoreX and Ncore_MP series
USABLE Internal dimensions: 280 (D) x 190 (W) x 57 (H) milimeters
Price for each case: 130€. Both cases 220€. PP fees + shipping not included

They can be supplied with hypex amps. If interested, PM me.

I bought this receiver about 30 years ago and it has been doing quite fine all this time.
Recently one problem appeared: the Radio forgets its presets when power-off.
I've found a post in this forum about a somewhat similar problem related to a 5-10 years younger AV model that has got a CR2025 battery inside.
I've been searching in the STR-GX40 service manual and I have not been able to find a battery symbol on the schematic diagrams.
Question: Would anybody have an idea how this receiver is storing presets (what technology is used? ), on which of the many PCBs inside is this stored and maybe which component would be defective?

Looking for a few pairs. NOS only please.
Payment by Paypal and willing to ship to Manila Philippines
Thanks

https://www.bmsspeakers.com/index.php-138.html?id=bms_15cn890
Ill be using Mini DSP for crossovers and EQ
this will be for home LCR and 18CN862 subs
Yes/No Suggestions

Keith

is there a connection between 0.707(critically damped sealed box Qtc) and 0.707 as in (sqroot of 2)/2?

im retarded… But it’s fun 😝

Hammond, Edcor and??
Is there anything else on a market reasonably priced and easy to order?

1. Would there be a difference between felt diffraction that is a circle with a hole for the tweeter vs the rectangular felt pads that is shaped like a square around the tweeter?
2. Would all loudspeakers benefit from felt dffraction pads?
3. Is there a formula for the diameter of the hole for the felt pad with respect to the diameter of the dome tweeter?

DA converter module with dual PCM1702 (balanced mode), regulators, I/V stages and output buffering taken from ML 39 CD Player; $200 OBO.

New Reliable Capacitor REL-CAP RT .1uF / 200V high quality Polystyrene film capacitors. Great for use in Parasound HCA-2200II and HCA-3500 stereo power amplifiers for power supply bypassing. Sold as a set of four (4). Recommended by John Curl! USA shipping only. $20 plus First Class mail cost. PM please.

I have an 834p where the switch is not being held close to the chassis. The nut that should be holding it has come undone and the threads stripped. Any suggestions of a part to use to replace the switch? Also, any insight how to remove the on/off knob? There doesn't appear to be a set screw, but the knob seems firmly in place.

Howdy, y'all!

I'm an electrical engineering student, and I've been learning about and experimenting with audio for quite some time.
My current setup is a pair of KEF Q100s, powered by one of the dayton DSP board amps with a custom EQ curve applied.

I recently have been interested in multiple-entry horn designs, hence why I came here since it seems that the community is fairly active and interested in them.

SOLD

Asking $45 $35 to include USA shipping

For sale are 4 boards from Michael Stark, I got on the big auction site. Three were built up, one is bare board. I have the original description of the boards, BOM, and schematics which will ship with the boards. Only parts as soldered and shown in the pictures are included.

I understand there have been concerns about the reliability of these boards, and I was planning to change over the full preamp board, by desoldering and reusing the parts to this design:

https://www.diyaudio.com/community/threads/the-ultimate-tube-preamp-power-supply.389308/

The two filament DC boards were used for 6SN7 tubes for about 100 hours without issues.

The one high/low power board was tested with a tube rectifier supply and filter choke and worked at the testing stage, but was never put in circuit. The other high/low board is bare. There is red enamel on that board over one area of solder mask scuffing.

I have a single Lavoce tn131.00 and need a second, as they are currently out of stock in the US until June. If you have one, or a pair, to sell let me know.

Hi ... does anyone know or have a reference to the force exerted on the tonearm at the stylus point?
Nor am I talking about antiskate as this will be for a linear arm.
Zene

Story time,
Here I am looking around at my dream shop (cabinetry, wood and metal fab) wondering how to have a little fun on the weekends. I retired mostly from live audio and recording industry about 6 years ago. My new business partner is talking about experiences he had with old school Turbosound and L-acoustic rigs as if he could remember the sound quality compared to modern stuff. I have acquired a little piece of land on which a bunch of audio tech, friends and family gather for fireworks & BBQ when the touring schedules are permitting it. I used to rent an AC generator and a PA system (like Nexo M6 / RS18) for those events but soon find out it was much overkill for most of the time since the jam bands don't even make it to the event sometimes. We end up using 10% of the SPL for ambiance music and karaoke our way through the night. Me and the boys then started messing around with car audio to replace those little JBL Bluetooth mini boom box that are just no fun at all besides for a crowded beach. That's when I found out about little tinny all integrated class D amps from China that run on 24v and have a sub output with adjustable low-pass filter. Since I had zero expectations for the quality of my 35$ by-amp system, I ordered the cheapest 4" car coaxial speakers and 6,5" subwoofer from amazon, watched a couple of car audio subwoofer maker videos and installed WinISD on my computer. That's how I found out how difficult it is to scale a box design for a smaller driver... I ended up with a baffle arrange at 90° and two different ported chambers on each side. One was 42,5L and the other 13 L. I made the ports long and narrow so I could tweak them by jamming wood panels in them to adjust the tuning. My old Smaart program was useless since I was metering the room as much as the box. (Even in a 40' x 40' x 16' garage!) I then checked if the impedance by frequency curve from WinISD was matching my observations and it was off by 3 Hz at both peaks. I took that result for a win even if I lack the knowledge to compare but one thing is for sure, I was hooked to building my own speakers. I then found out that the little port the software told me to put on my boombox top boxes, in relation to the volume, was really giving the boost at around the same frequencies the software was predicting. They don't sound good, but still, they flatten the response. Smaart was helpful in that range. The boombox perform well enough that the boys now want to make me listen to their last recording mix after a couple of beers. I made two other copies for friends who use power tool batteries as PSU and they’re still going strong. I even solve the karaoke thing by using a little 9v premp and mixer.

I now want to learn more about physics, driver parameters and simulation tools so I can figure out more stuff to build and have fun with especially since the fabricating is almost instantaneous for me. (Materials in stock, CAD, CAM, CNC router, sheet metal, paint booth, industrial woodworking tools, cnc lathe & milling, etc.) I feel like a spoiled kid. For now, I'm more into DSP and sound over IP stuff to mess with as for my commercial and PA back ground but I will get to the HIFI stuff eventually I'm sure. My first order of business is a mini line array PA that will replace that first project. I saw 16 channel audio interface with dsp on each of them that are available for less than I toughed possible. To me, that means I can purchase Amp and PSU modules and fiddle my way to the LO-FI mini line array PA or Atmos territory.

Thanks for reading this, I'll be in the subwoofer forum asking about a silly 6,5" driver Mini Paraflex-C box design.
Long live this great forum!

Excuse the basic thread/tittle but I have never really had to shop for a speciifc heat sink before!


I need a heat sink for two TO-220 devices that are currently bolted to the top of a tube amp's top panel, the 4-40 bolts are 38mm apart. See attached pic.

Where can I find flat heat sinks from Mouser that I could drill and tap for 4-40 hardware?

Thanks!

This amp came with 4 bad bipolar caps 10uf. I replaced with 2 22uf. Amp comes on and relays clicks. But as soon I give signal the relay starts to go off and on cycle. There is good output signal on one pin of relay. I tried to force relay to come on but then Amp tries to pull current and goes into protect. All the output mosfets have good gate oscillations.

I bought a 2nd hand nc1200 amp and want to redo the signal wiring. One of the signal cables is too short and the nampon wire was cut (?). I want to replace it and contacted Hypex- the cable is only $8US but they want $75US for shipping!! Does anyone have an extra they could sell me or know of a vendor who can supply one from the US?


Thanks for any help...

Hi Everyone,

It's been a while since I've been posting on this forum. I thought I might share the schematic and possibly PCB layout of the 'Spartan 10' phonostage, which I designed a couple of years ago and made into a commercial successful product, selling the last one in December 2022. Hopefully this counts as 'DIY' as I did indeed do it myself! Among other features it has...

• Superb RIAA accuracy to ±0.1dB, absolutely none of the usual colouration found in almost all other phonostages that barely make ±0.5dB or worse
• Spotlessly clean high frequency reproduction, through the use of limited high frequency negative feedback on the uncompensated input amplifiers
• Very low distortion, from double-stage design that shares the amplification between two amplifiers stages
• Low noise input amplifiers, optimised for real moving magnet cartridge impedance characteristics
• Low frequency crossfeed, a unique switchable filter that cancels low frequency noise
• Mono switching for getting the best out of mono pressings
• 3rd order subsonic filtering from 22Hz
• A fully linear split supply with start-up relay muting

It's a pretty straightforward single-page schematic, but works very well.

MF

The original Hitachi 2SK1058 2SJ162 have long disappeared from the market. NOS are very expensive and from unknown source. Some new MOSFET power amp design use the RENESAS 2SK1058 2SJ162 instead.

Currently, Mouser has the Renesas 2SK1058, but the 2SJ162 is out of stock. You can buy the pair from parts house in Hong Kong. Some even offer matched pair for additional cost.

What is the assessment of the RENESAS 2SK1058 2SJ162 in audio power amplifier construction?

I'm looking for the transistor that goes in Q-2_2 in the pic. This is a hifonics brx3016.1D

Would any of you be so kind and give me the core dimensions and/or the dc resistance values of the original A-470 transformer?
I have the winding data but would need this additional data to be able to check if my attempt to calculate winding Rac/Rdc relation and proximity loss real/imaginare part is correct.

Complete data from ANY other OPT/amp combination would do as well.

Ideally, what i would need is the following:
Amp circuit diagram, specs, frequency response curve and measuring conditions
Core dimensions
Winding build up
Isolation build up
Primary and secundary turns per layer
Primary and secundary wire size
Primary DCR

Thank you for any assistance
Pete

SOLD

Asking $200 or best offer, to include USA ground shipping.

I am clearing out some wire from the stockpile I will likely not be needing. Most of the wire is 600V wire, unless otherwise noted. Most comes on spools, but some of the PTFE finer gauge wire, and the KV 18 gauge wire are in baggies. Most is USA made, but the BNTECHGO is from China. I tried to estimate feet remaining on the spools, but I am sure I was conservative on all of them and you will get more wire than listed.

26 lots in total

CHASSIS WIRE

1- BNTECHGO 14awg, 20 ft each of black and red
2-BNTECHGO 16awg, 20 ft each of black, red, white, green and blue
3-Vampire cryo upocc 18 awg solid core, 10 ft each of red and black
4-Chinese 18 awg silicone insulated stranded, 20 kV high voltage, 25 ft of white, in bag
5-Milspec PTFE silver plated copper, 18 awg, 20 ft of green
6-Alpha wire, pvc over solid copper, 18 awg, 5 ft of black, 10ft of yellow and 10ft of green
7-Milspec PTFE over silver plated copper, metal spool, 18 awg 75 feet of white
8-Carol pvc over stranded 20 awg copper, 20 ft of black
9-Alpha 20 awg pvc over solid copper, 25ft of red and blue, 15ft of black, 10 ft of yellow
10-Alpha 20 awg PTFE over silver plated solid copper, 15 feet of white
11-Milspec PTFE over silver plated copper, 24 awg stranded, 30ft of white, 30ft of wht/brn, 30ft of red/grn all 3 in baggie
12-Milspec PTFE over silver plated copper, 26awg stranded, 30ft of purple, 30ft of wht/org, 30ft of wht/rd/brn, 30ft of wht/blk all 4 in baggie
13-Milspec PTFE over silver plated copper, 28 awg stranded, 30ft of purple, 30 ft of rd/wht both in a baggie

Enameled Magnet wire

1-Belden, 18awg, 30ft.
2-Remington, 18 awg, 10ft
3-Belden 20 awg, 100ft
4-Belden 24awg, 150ft
5-OCC 24 awg, on cardboard spool, 50 ft.
6-Belden 26awg, 400ft
7-Fay 26awg, 400ft.
8-Belden 28awg, 400ft

Packed in a USPS Large Priority Mail flat rate box.

SOLD

Asking $120 or best offer, including USA ground shipping

Wire spools I likely will not use in the near future, ready for their next home. 600v wire unless otherwise noted

All are poly/pvc coated, USA sourced wire.

22 awg

Carol brand
1-solid core, 40ft of brown
2-solid core, 40ft of white
3-solid core, 30 ft of white
4- stranded, 30ft of red
5- stranded, 25 feet of black

Alpha Wire
6-stranded, 40ft of black
7-stranded, 35ft of red
8-stranded, 1000v, 20ft of orange
9-stranded , 1000v, 20ft of gray
10-stranded, 1000v, 30ft. of brown
11-stranded, 1000v, 35ft of purple
12-solid, 1000v, 60ft of black
13-solid, 1000v, 60ft of red
14-solid, 1000v, 60ft of white

24AWG

Alpha wire, all stranded

15- 50ft of red
16- 50ft of yellow
17- 40ft of blue
18- 50ft of brown
19- 30ft of gray
20-20ft. of white

shipping in a USPS medium flat rate box

Does anyone know of a reliable source for Toshiba 2SJ313/2SK2013 FETs?
There are a number of listings on EBay, but I do not know if the parts are genuine.

I recently got AT-OC9XML cartridge and I want to build op amp based MC only preamplifier that's powered from USB power bank. I decided that I use the circuit of Phonoclone from RJM Audio.

I could use DC-DC converter to step up the 5V USB voltage to 24V and use TLE2426 to split the rails for +12V and -12V.

But I'd like to keep it more simple and use rail to rail op amp. There aren't many op amps out there for audio use that are designed to be powered from only +5V. One such op amp is LME49721.

I came up with this schematic:



I have lots of those USB-C connectors so that's what I'd use. R2 and R9 set the gain. AT-OC9XML has 0,4mV output so 180 ohm would give about 55 dB of gain for 0,7x line output.

As there's no negative voltage rail DC offset would be pretty high so fairly big output cap is needed. Before I start with the PCB layout I'd like some feedback about this. I'm an electronics hobbyist for many years but I'm new to audio circuits.

My idea is to make this SMD only build that would fit in slimline Hammond 1455B1002 (100x72x19mm) case.

Can anyone recommend a way to place a thermal pad in a filled zone?

George

Are there any N.Pass amps that have a front end using parts widely available in 2023, i.e not SK170/SJ74?

Or circuits that can use replacement input devices widely available in 2023?

Hello,

This are my last DAC. The pictures are self speaking.

First pictures are with test boards single side and the last are with the finished pcb, double side. The last one it is the block diagram.

Hey all,

I'm hoping someone with prior hands-on experience can help me. I'm considering a 3 way using a Hypex 3-way active plate amplifier and ScanSpeak components. For the midrange I can pick either a 4 or 8 Ohm driver which is broadly equivalent except the usual: The 4 Ohm version has 3 dB more output at the same voltage. 87 vs. 90 dB.

The 4 Ohm has a minimum Z of just around 3.6 Ohms, while the 8 Ohm has a minimum Z around 7.5 Ohms.

Given this is an active design, and my choice of amplifier, and equivalent maximum power handling (80W) for both, is there a reason not to use the 8 Ohm version? My inclination is to think that this plate amp will do better > 4 Ohms than below so I should stick with the 8 Ohm version.

Thoughts?

Thank you,

Erik

https://insolvencyintel.co.uk/mqa-l...qDjxkx-MgW9jkuDNRHYa0zeQ17wLjf22yOKuXwoHmv74U


MQA LIMITED

Appointment of Administrators
In the The High Court of Justice
Court Number: CR-2023-001732
MQA LIMITED
(Company Number 09123512)
Nature of Business: Sound recording and music publishing activities
Registered office: 2nd Floor, 110 Cannon Street, London, EC4N 6EU
Principal trading address: 11 Latham Road, Huntingdon, Cambridgeshire, PE29 6YE
Date of Appointment: 3 April 2023
Names and Address of Administrators: Philip David Reynolds (IP No. 21190) and David Hudson (IP No. 8977) both of FRP Advisory Trading Limited, 2nd Floor, 110 Cannon Street, London, EC4N 6EU
Further details contact: The Joint Administrators, Tel: 020 3005 4000. Alternative contact: Maya Hettiaratchi, Email: Maya.Hettiaratchi@frpadvisory.com
View the original Gazette notice

Hello friends,

A while ago I bought an immaculate pair of JBL 2213H for a very fair price. I have always heard that these woofers produce a very clean and deep bass in large enclosures. So I decided to build a pair of speaker out of them. I got a pair of Morel TSCM 634 midrange drivers and a pair of Aurum Cantus G1 Ribbon Tweeters from Parts-Express. After two weeks of measuring and building xo, I managed to get a very flat and surprisingly fantastic sound from them. The only issue is that the woofers still play bass frequencies of 100-50Hz a little too loud for my taste. The test cabinet I have put them in right now were built for a DIY JBL L100T (ten years ago or so). I guess they are like 60L or maybe a little bit larger.

According to WinISD a volume of about 100L with a long port of 26" (length) and 4" (diameter) should make them sound right. So I have decided to use PVC swage pipes and use 90-degree bends to make the port fit. Please see the drawings attached.

Any input about what I am going to do is greatly appreciated. Do my calculations make sense? Is the port OK? How about, if the vertical end of the port goes even higher than the woofer? Should I be worried about any kind of distortion or resonance from such a port?

Please see the attached pics.
Thanks.

Hi guys.
Can a brand new preamp tube suddenly go bad?
I am working on an old (and heavy, 31 kgs!) McIntosh MC275. While measurering voltage on different sections, it suddenly started to hum on one channel. I had nothing connected to the inputs. And it hums independent of the volume setting.
After checking all possible ground connections, I began swapping the KT88 power tubes, hum did not change. Then I swapped the preamp tubes. It has one 12AX7 for both channels, and then for each channel a 12AU7, 12BH7 and 12AZ7 (mine uses 12AT7's). When swapping the 12AU7's, the hum changed to the other channel. Then I used 2 working 12AT7's (cause I don't have 12AU7's) and hum disappeared almost completely.
Does that mean that one 12AU7 has become bad?
Thanks in advance.

Hi!

I would like to ask you for your advice about simulating bass reflex speakers.

My wife and me are about to build four 15 inch ported speakers for the local Reggae sound system. We are new to building loudspeakers. We are insecure what to build because simulators seem to disagree.

We would like to use the speakers above four 18 inch scoops between 80 Hz and somewhere near 400 Hz. The speakers will be close together in one stack and run in mono.

We did our simulations with Hornresp and with WinISD. We wish to thank all people who write and maintain these programs.


Hornresp shows a Helmholtz frequency of 55.1 Hz and a frequency response that falls by 1 dB between 70 Hz and 200 Hz. Falloff is very gradual. WinISD says the same cabinet is tuned to 71 Hz with a narrow 3 dB resonance near 88 Hz. Impedance minimum in each program is close to the frequency that the program states.

For this simulation we used the JBL 2226H datasheet, four cabinets with 87 litres each in half-space, cabinet resonances are masked. Temperature 20°C, inductance is included. Did we get something mixed up? Here are our input screens for simulation:


Should we worry about the peaky response from WinISD? The fall-off with frequency we get from Hornresp would be welcome but we're afraid of the peakiness in the WinISD result.

We are planning to tune the ports after assembling the cabinets but as it is, it's difficult for us to find a usable range for port length.

We imagine it's difficult to simulate the right kind of coupling between speakers in a specific case. We are aware there will always be some difference between simulations and measurements. Can Hornresp predict a peaky or flat response with multiple drivers? There have been some similar threads before but they seem to be asking different questions. We would be grateful for your help.

Best wishes
Axel

EIKI LC-XB21B / Sanyo PLC-XW57 lamp ballast did not ignite HID lamp. Projector did not give any warning with LEDs, just 3 times try to start and then cool down lamp and goes to standby.
I find on ballast board 2 diodes are dead. They are in series and together parallel to output, middle point is used for ignition transformer primary (or secondary) side supply. Probably, as I not had schematic. Ballast is Rubicon RPB-7491EA, PCB is D7491M-03.
What parameters must have replacement diodes? Marking on diode is 83A, D5 on image.

I got into 3D printing and I think I have started already too many threads here, so I am starting this one to share my 3D printed audio stuff.

The first one is a back cover for BC 8PE21. I printed it with only 11% infill to use some leftover filament, for strength I think it would need more. Also, the strength could be improved by adding ribs - especially on the flat part, the sides seem OK. Its intended use is for using the 8PE21 with a RCF H6000 horn or with the 135 Hz midbass horn by John Inlow. It fits the driver fine. For me, making one from wood would be a nightmare. 3D printing is easy🙂

Edit: Here is the index of the posted models from page 2 on:
Post #17: Mount piece for Visaton FRS8M (by arcgotic) 3D printed audio stuff (with STL files)
Post #25: 20 cm paraline (not the best design, for experimenters only) 3D printed audio stuff (with STL files)
Post #61 Screw in driver to 3" diameter two screw bolt on (may not work for all drivers) 3D printed audio stuff (with STL files)
Post #65 8PE21 front aperture 3D printed audio stuff (with STL files)
Post #101 34c9 base 3D printed audio stuff (with STL files)

Some more K-tubes: https://www.diyaudio.com/community/threads/3d-printed-audio-stuff-with-stl-files.349459/post-6890665

SOLD!


Sonore Audiobyte, working pull from parted out TP BIII 9038 Pro DAC. I was running in synch, using clock on Audiobyte. Was using it with Roon (showed up as unidentified I2S bridge), played native DSD128, but it also connected and played from Win 11 laptop. I have a DIY manual which was copied from a post at Audio Circle. It explains the built in oversampling controlled by dip switch and how to power the USB side, if desired. I always powered it with 5v. Still a great sounding isolated USB to I2S module. $125 shipped in CONUS. Sonore has a basic description and old drivers link on their discontinued products page.

https://www.sonore.us/legacy.html

SUPPORTED PCM RATES
44.1 KHz-384 KHz

SUPPORTED DSD RATES
2.8 MHz (DSD64) - DoP, native (via ASIO)
5.6 MHz (DSD128) - DoP, native (via ASIO)
11.2 MHz (DSD256) - native (via ASIO)
22.5 MHz (DSD512) - native (via ASIO)

I'm scompracer on ebay. 100% positive feedback, 514 transactions, 133 as seller.

https://www.ebay.com/usr/scompracer#tab2

What would be considered an upgrade to my Alpair 7 Gen 3 drivers? I was looking at the FF105WK drivers but I'm not sure that these would be an upgrade. I use a subwoofer in my system, which is mainly used for You Tube music videos. Thanks for any responses.

Does anyone have or know where to find measurements of this driver?

Mostly interested in burst decay and phase response

40ies design

can somone please tell me why it is my yorkville parasource ps12p is giving out 7volts ac and 5 volts dc on the woofer output?, it is making a sort of a screaching noise on the loud speaker, please tell me what can cause this

Alright, let’s get crazy and build (in our mind) a state of the art sealed speaker cabinet and replace the internal air with other gas of other properties, for example Helium.
As sound waves travel differently through different mediums… what would you think the outcome would be?

Hi everyone!

I'm building a copy of a 1953 marathon tube amp and have ran into an issue replacing the two selenium rectifiers with 1n4007 diodes in the new build. Keeping in mind that the diodes go in reverse order from the selenium, I've wired it up to match the original.
However, the circuit isn't working, I get 119v to the first tube heater (50l6) and onwards to the last three tubes (PP 50L6 with two 12SC7s) the rectification circuit isn't generating B+ to power the rest. No voltage past the first cap (C1) I've attached a schematic of how it's currently wired. Beating my head against the wall, because it's wired as the original but no B+! What do y'all think? What am I missing?

I am about to build a new set of subwoofers, based on either Faital 12PR320, or BMS 12ND630
Since, I will have a lot of room-gain, I was thinking about making it sealed, not ported.

I will have the possibility, to perform EQ, and I like the idea, of playing with REW, rather than fiffle with the ports.

My plan is to buold a 60 liter enclosure, realizing that EQ will be needed.

What are your thoughts, regarding a sealed anclosure?

Greetings from Denmark, Michael

Hello all
Thinking of something DIY hack against drive failure and power outage attached to the main pc. This pc has a dongle with 8 Bluetooth connection ability and a really good Wi-Fi dongle. The 65" screen attached to this is the main screen for entertainment, DAW, pc monitor

Pair of USB flash drives in raid 1 on a powered hub plugged into a solar topped powerbank? Will this work as a cheap raid 1 array accessible by all the devices on the network?

Thanks and regards
Randy

Matched pair of tubes used for about 40-50 hours in like new condition with original packing. Price is 300 euro including shipping to EU with tracking. Payment paypal for friends.

Hey folks,

I need some guidance here. I have some experience on class a/b amps, have troubleshooted and restored a lot of pioneers, marantz, realistic, etc...
But this is my first Nikko power amp.
I have replaced all electrolytic caps, and a few faulty components: 4 out of 8 output transistors were shorted, so I replaced all output transistors and a burnt fusible resistor.

2SA1095 -> 2SA1215 (Q733,734,737,738)
2SC2565 -> 2SC2921 (Q731,732,735,736)
2SD882 -> KSD1691 (Q727, 728)
2SB772 -> KSB1151 (Q729, 730)

There is no bias offset adjustment on this amp, just IDLE current adjustment trim pots, but the TP testing points are not showing anything usable.
Power supply seems fine, the rails are providing correct voltage but some of the output transistors are showing incorrect voltages.
On the left channel the negative side of the circuit has displaying some positive voltage on most transistors, Q733 and Q737 bases are 26v, when I presume should be showing a negative value.
On the right channel a similar problem is happening but in the positive side of the circuit...
I simply "copied" the original placements of the transistors (there are no shorts with the heatsink).
I am not leaving it on for long since it can burn something, It is drawing about 1A @ 127V.

I need a peer to review and help me to troubleshoot this issue.
DMM, o-scope, thermal camera, etc are available...

Looking to build a pair of line source/column speakers for mids-top from 250hz up. I like the width and throw of the line source design, as well as its portability. It's for a little PA with 12" Cubo kicks on each side, and a x2 12" centre cardioid sub. (it's for that sort of music with lots of head/brain Bass, rather than body bass), to be used outside in the summer and low-ceiling basements in the winter, for like 200 people.

Thinking of a column with a minimum of x8 drivers close together to minimise comb filtering using either 3" or 4" drivers.
What do people think of using a 2-way driver like a JBL stage2 4". Then I dont have to have a separate tweeter in the middle (if i did i'd go for a planar) ... unless i build a curved design, due to top end due to cancellation. If the 2-way idea is bad, I'd go for a FaitalPro 3" FE22 or Peerless TC9FD00-04

Any plans anyone? Or tips from experience? I'm fairly new to speaker building.
Hoping to find some tested plans or experience here or someone to persuade me to build something else and not buy a pair of proBox Achat 804. advice, please.

Hey guys! I'm Jos, an embedded hardware engineer from The Netherlands. I am into vintage audio gear by hobby, but also really like a modern smart home. Right now I can turn on my audio setup with a smart power outlet, but I don't have many means to change the volume or input. It just feels wrong to get a modern surround processor connected to classic systems.

Here is the solution I came up with:


In summary:

• Full analog audio path with opamp amplification and a relay based attenuator.
• ESP32 DEVKITC module for relay control and wireless MQTT integration with Home Assistant server.
• Every channel wired up to ESP32 ADCs to switch output based on what input is playing.
• 12V Trigger output for semi modern power amps.
• Two rotary encoders and a round smart watch IPS screen as the user interface.
• Neopixel output for good measure.
• USB C power input with switching converter and linear regulation.

This is the power supply plan:


The idea is to use a TI TPS65130 symmetrical switching converter to change the 5V USB input to a +/-12V output which is cleaned up by a TPS7A49/TPS7A30 low noise LDOs for super clean +/-10V for the opamps. We can then steal the 12V for the trigger output. The remaining 3.3V we can take from the ESP32 module.

The end result is this circuit board:


A mockup for a 3D printable enclosure is also getting closer:


Finally, I have a lot of code to learn. ESP-IDF with the LVGL graphic library got me this for now:


I am gonna pull the trigger and order the PCB next weekend or so. I have attached the schematic. Does anyone have any feedback or ideas for now?

Hello, I am trying to find a replacement for this cap. Can't tell if MKT or MKP etc. They are for the output stage of a DAC (1uF, 63V apparently). Thank you.

Grounding issues are a pain, and trying to sort out a unit someone else has messed with is a pain. Here I have both issues in one.
Someone had messed with ground wiring at the input terminals. I think I sort of got it how it should be but am still having a weird issue. I've done a recap/overhaul on the unit but am stuck on this grounding issue.
Currently, there is a buzz in both channels.

Originally if I had a signal connected to tuner or aux it would bleed through when unselected. Distorted and at normal listening levels, unaffected by volume. The ground wire from the input switching board had been grounded to the ground of the input jacks. When I put it on the chassis this stopped happening. But there is still a buzz in the output. Unaffected by volume as well. And it is coming from the preamp as it is gone when I run a signal directly into the amp. It did seem to make some difference to the noise where I grounded this wire. If I grounded it to the ground bus at the main caps, it was louder than when grounded to the smaller bus near the terminals.

Here's the weird part that I'm hoping will give enough of a clue to figure this out.
If I ground the input signal to anywhere on the chassis, I get that distorted bleed through again. That definitely isn't normal.
I'm pretty sure this issue was here before I did my work, but someone was in here before.

Any ideas?

Greetings from Vermont
I have a Dayton SA1000 which seems to be in excellent condition. When I ran it through the pre out of my old Yamaha DSP -A3090 the volume was extremely low from a 15” sub. So I ran it through a smaller sub still minimal volume. I am not in anyway versed on repairs in regards to audio equipment. I do have a bolt meter and can follow some basic instructions. Any suggestions would be much appreciated.

The F4 is finally back home, a few adjustments, some soldering of components which were not correctly installed, bias adjusted and voltage stable at 200mV as per project, I will soon insert it into my chain past the Audio Research SP9 while the BA-3 preamp in the build as to have an extra voltage on the output to drive the F4 but I am starting to itch at what comes next, what about a big box with both preamp and power amp, kind of a Class A integrated amp with about 50W output?

Hi everyone


Trying to troubleshoot my Orion HP 4800. It powers on and works however the rear ch3/4 speaker output is very low. Gain has to be turned up almost all the way and even then it is very hushed. I assume it is some sort of fault.

When connecting the 3/4 channel to 1/2 channel speakers play nice and loud.

ESP light is constantly on.

Hi,

I've built a few diy subwoofers with good results. I uploaded a pic of one I built. I want to build one more with a 15" driver for more output. I listen to mostly music and some HT. I love tight bass with no distortion. I also am into wood working so I can make any size box and have room for a nice size sub. I did want to go ported. I'm really lost on drivers and was wondering if someone could help steer me to a great 15" driver for a home subwoofer. I have a bridged amp putting out 625w at 8 ohms but may decide to go with a more powerful class D power amp. First I'll try what I have. When I called Parts Express they suggested this driver: https://www.parts-express.com/Adire-Audio-ADBR15D2RA-Brahma-15-XBL-DVC-Subwoofer-294-116?quantity=1 My budget is around 500.00 for the driver.

Any help is appreciated.

Any suggestions of measurement hardware?
OmniMic V2 / DATS V3/CLIO/ milliohm meter /Earthworks
I currently have a Behringer ECM8000 for live PA , not sure if it is good enough start.
Thanks

I bought the amp used from USAM and received it today then proceeded to set it up.

Set up consists of:

Parasound A21+
Rogue RH-5 preamp
Yamaha CD-S1000
NAD C658 DAC/pre
Mirage M760 speakers
A mix of AQ Water and Acoustic Zen Matrix Reference interconnects
Zu Audio speaker cables

As soon as I powered it up there was a very apparent and loud hiss coming from the right speaker. Left speaker is quiet.

I replaced the speaker cables and checked all connections. Hiss still present.

I used both balanced and unbalanced cconnections. Hiss still present.

I used multiple sets of balanced and unbalanced cables. Hiss still present.

I put in place a new set of speakers. Hiss is still present.

I swapped out the preamp. The hissing is still present.

I replaced the A21+ with my Pass Labs XA-25. Hissing sound is gone.

It is loud enough my wife could hear it in the next room, she has very sensitive ears. Unless you are aware of something I am not I cannot fathom where the problem lies.

I know enough to be dangerous about working on these electronic devices so I don't want to accidentlly blow something up.

Any insight from the significantly more experienced will be greatly appreciated.

Jay

On the old forum software it showed a signature at bottom of messages.
I used this for my website.
Seems to have gone missing in new forum software.

Hi,

A friend of mine bought a defective SONY TA-VE800G, since it fits the look of his other Hifi Components (Yes I know...)

The right channel is very distorted and has almost no power, at first I thought that would be an easy job, replacing a transistor or a cap.

But since the problem is not comming from the preamp nor the power amp, I am a bit clueless, maybe someone has an idea?

Also I have a quick question on the side, that "AV Reciever" doesn't have any surround input, so how the heck does it make surround sound?!


Greetings,

Plermpel

Hello, I am trying to find a replacement for this cap. Can't tell its type. They are for a DAC board (2200pF, 100v, 2.5% apparently). Thank you.

I'm building another pair of Ripole subs and sharing the build pics here. These are a bit more compact than my earlier builds.

The woofer cabs are 3/4 red oak plywood with oak edge members inserted and rounded over. This arrangement looks better than exposed plywood edges but it's a LOT more work. The "C" center section is solid brown oak indexed to the cabs with oak dowel pins. The cabs and center section are held together with all-thread rods and button head cap nuts.

The light-colored cabs will be oil stained with a mixture of 1 part golden oak, 3 parts natural, and then a bit of powdered turmeric root is added for a yellowish tint. The brown oak center section will have a darker red oak stain for a nice contrast. The finish will be two or three sprayed-on coats of clear satin polyurethane with a #320 sanding step between coats.

More to come as I complete them, but for now-- enjoy the build pics.

Below - Rabbited cab panels bank together for gluing:



Below - Cab glued and clamped:



Below- Cab edges notched on the table saw to accept edge inserts:



Below- Red oak edge inserts held in place with stretched painter’s tape while the glue sets:



Below- Cab with mitered edge inserts glued in and sanded flush:



Below - Woodwork completed on cabs and center C-section:



Below - Rear view of assembly with edges rounded to 3/8” radius on a router table:



Below - Front view, ready for stain & satin clear coat.


Below - Details stained and first coat of satin poly clear sprayed on:


More to come…

Hi Guys,
i would like to know what the best resistor for a power supply with CRC circuit? thank you! Maxpou

Pair of tubes from Valvo Germany. I buy this about 6 months ago and used it about 100 hours in my 300b amp. They sounf verry good and there is no hiss and no hum. Price would be 40 euro plus 8,90 shipping with tracking inside EU. Payment paypal for friends.

Pair of chokes 10H 200mA 82 ohm. In top condition verry little use. I buy this by mauser for 75eu each. Price for bouth is 100eu including shipping to EU with tracking.

Rod Coleman pair regs for dht tubes pcb revision 7 with complete pair of raw dc supply. Iv used this with 300b tubes with top results. Price would be 100eu including shipping to EU with tracking.

If I had a trio ka6004 amp but had to give it away. Regret and the rest ever since. Can anyone help me on where I could replace it?

I have 5.4 mtr brand new supra lo rad mk2 2.5mm core shielded mains cable inc drain wire £97 worth sell £70

Hi,

Has anyone heard/measured the SB Acoustics PFC coaxial drivers with the "factory" crossover?

SB Acoustics, SB12PFC25-4-COAX (4 inch)
SB Acoustics, SB13PFC25-4-COAX (5 inch)
SB Acoustics, SB16PFC25-4-COAX (6 inch)

I am most interested in knowing how they sound, as I am willing to use 4 or 6 of these for ATMOS and SURROUND duty.

XO are designed by SB Acoustics team and curves are optimized for 15° off-axis.

Cheers

Hello everybody,
by no means, I'm an electronics "guru" quite the reverse.
I will appreciate if someone explains me in the simplest terms how to wire Hypex NCAS500MP H-Bus connector J7.
This amplifier has two power supplies, a standby supply and the main power supply (PS).
Would like to avoid damaging the amplifier with faulty wiring, this is why asking for very much needed help. A manual for the present amplifier is attached.
Questions I would like to ask for help to answer :
1. To activate the main power supply (PS) and power the amplifier. Is it J7.3 to J7.9 pins must be connected (wired together) ?
2. A standby supply. If I have understood correctly, can be used in external power supply 3.3VDc to 12VDc. This method is favoured by Hypex .
Is it J7.1 and J7.2 pins are used for that ?

Had a pair of these for a number of years. Are they any use ? Worth anything ? Are the magnets alnico ? Any information about them really.

On the back of one of the magnets it says :

Custom built
Allen organ
8 ohms 292 0008
67 7243
031