I have some midrange speakers that I'm trying to design a ported box for. I'm a bit confused about what frequency I should tune the port to.
Another question is: when tuning the box in WinISD, should I aim for a flat graph or a peak? The aim of the speakers is not SQ but rather loudness. but I am unsure if I am better off with a flat response or huge peaks at around 250 Hz (that's what I was able to reach with a non-negative port). I have atteched a picture of the "peak" respons box

Hi there
It is some while for me writng again something. Personal things led me away from audioo hobby.
But i am back and have much fun again with building stuff.

Lately build an Hiraga amplifier with PCB' s friom Jims audiio, the kubota reg version
I decided to give it a LCL poiwer supply with 80 mH Lundahl chokes LL2772. After first fire up it sounded rather good, but after few tracks and some run in the upper bass is too loud, and bass is boomy, and treble with shshs sounds. Though i calculated the LCL ps with Duncans PS designer it is not sounding right. After removing the chokes out of circuit and there in place 0,33 ohm resistiors, so in fact a Pi filter it sounded much better. Better bass responce and less sibilance

This is my first attempt:
500VA toroid transformer to bridge rectifier with Fets ( diyaudio group buy, from Prasi) > 75000uF> 80mH choke> 31000+31000 uf, each rail/ and each channel apart
so per channel total of 274000 uF of capacity

LL2772 choke is connected in common mode fot extra filtering, the 1+ A bias DC current is then counteracted in the core of the choke

Maybe i should have chosen a bigger coil with less resistance, or add a resistor after the choke, or should choose another capacity distribution (eg first 31000 then choke, then 75000+31000 to amp.)

Matter of fact is the filtering looked good on PS designer, but in AC function with music it is a whole other story. Does anybody have same results with CLC PS ?

Hi everyone, my name is Bruno, I'm Brazilian.

I have a pair of Yamaha HS8 monitors, in the signal input circuit, there are 6 NJM4558M op amps, I would like to upgrade to NJM5532M because they are faster, I fear the circuit will wobble.
Will I gain sound quality?
I see that some people put OPA2134 in place of NJM4558...
Could someone more experienced give me an opinion?


A photo of the input circuit board:


Datasshet NJM4558M:
https://www.njr.com/electronic_device/PDF/NJM4558_E.pdf
Datasheet NJM5532M:
https://br.mouser.com/datasheet/2/294/NJM5532_E-1917664.pdf
See pages 14 and 42 in the service manual.

Hi all! I was going to post this in the speaker forums, but now realize this is more of an amp question.

I have a lovely active Genelec 8040b studio monitor... but ... I would love to rip out all the electronics from the speaker and (safely) put them in a separate enclosure. Then the dream would be to use speaker wire to connect the woofer and tweeter (2 x 2-wire) over a modest 20ft cable run without any detrimental effects to sound quality. It would still be the same pairing of amp/speaker, and yes, before you ask, I would close up any resulting holes in the cabinet resulting from the surgery. Since this is a commercial product, I know this would void the warranty, but I don't care haha. I don't have a schematic, but the brochure states it is a class B amp design.

You might be wondering why on earth I'd like to do this? I need to put the speaker in a location where there is already 2 x 2-wire 14awg speaker wire in place, and routing 120V power is technically very difficult.

Before I open up the speaker and test this myself by splicing in 20ft of speaker wire, I would love to know if anyone has ever done such a thing?

Hi everyone !
I am planning to build a high output three way speaker using fullrange drivers for the midrange. Why not just midrange drivers ? Two things. From personal experience I have noticed that many fullrange drivers have cleaner, less distorted mids than a lot of said-to-be "good" mid drivers at the same or even at a lower price tag. Second thing, I will only be using first order crossovers for this project, so the mid drivers will have to reproduce a non-negligible part of the high frequency content of the signal, hence the need for the wide dispersion characteristics that come with good fullrange drivers.
So, what are your suggestions ? I am not able to listen to enough drivers to find the most appropriate one all by myself, that's why I'm asking.
Thanks in advance

Hello everyone!
I want to make a basic preamp for a low pass filter 300 Hz (5x stage [5x 10k ohm 5x 50 nF]).
So i made this PCB Design, no idea if it will perform well.
Any ideas to improve it?

Thanks for your time to answer here, its a big help 🙂.

Parts:

2] 1k ohm
1] 22k ohm
2] Red caps = 100nF

Hi, just currious about the famous Koda Preamp gain circuit. If we look at the few pictures available, seems to me it use the LU1014D, with some large Mosfet, with possibly a CRC supply filter, and JFET input buffer.

Parts choice seems pretty usual: vishay, PRP, and MFR25 film resistors, Elna for audio, Muse and Nichicon Rubicon VZ electro caps.
Even the power supply rectifiers seems to be on the board.

Anyone knows the used topology? Just curious…

SB

Looking to replace faulty one but cannot find a spare or vintage replacement-anyone any ideas?

Hi all,

Can anyone suggest a track, as I am running out of ideas searching where is the cause of my old Studer A730's todays issue : as soon as it's powered on, even if lid is open, motor starts spinning backwards at full speed and machine doesn't respond to any order. Swing arm goes full travel outward to disc end, lens tries focusing and laser beam is visible.

Machine fully overhauled 3 years ago (all electrolytics, fresh battery) and it has been playing faultless since. I hadn't used it at all during last 3 or 4 months, but until then it has been working flawlessly.

Some years ago it has been retrofitted by Studer with a CDM-4/16 drive (Neues Laufwerk für A730 Umbaukit MkII 1.630.027.81)

I checked all power supply voltages (+5/-5V, 12V, -15V) and they're all within specifications.

For the time being I'm lost...

I'm in need of 2pcs LND150N3 to repair a friends guitar amp. They seem to be unobtainium at the moment.

Thanks

Hi!

I am looking for tube buffer or preamp design using with 6DJ8 or maybe someone can suggest better tube for this project. Looking for very good soundstage, very low THD like 0,01% and less. Something that touches mind body and soul. I like to use one tube per channel or one tube for stereo buffer like Aum Acoustics Single Triode Tube Buffer. Can anybody point me to the right schematic to do something like this Aum tube buffer?

I am planning to use high PSRR power supply like 21 century Maida regulator for high voltage and for heaters also PSU with 100db PSRR. Balanced in and output option using some buffer or any better ideas how to solve that issue to use both balanced and unbalanced tube amp?

I picked up these sample schematics looking for very low THD, PSRR and good attenuated harmonics. It would be good if the gain for this buffer or preamp rather low. Planning to use sometimes up to 2Vrms input and output balanced 4Vrms option.

Please comment about these schematics and your experiences with this kind of tube amps like:


or


or

https://www.tubecad.com/2019/05/blog0465.htm
or


https://www.tubecad.com/2022/07/blog0561.htm

Any help and your experiences with a tube amps would be highly appreciated. 🙂

Good day, gentlemen

due to lack of time to realize this project i offer it for sale.
the main transistors have not even been opened by mouser and the others are new from my findings. I also have instructions with me.
I don't want to enrich myself but simply give it away at a fair price.alone the transistors are more expensive than this offer.
want for everything
€160 plus shipping

First watt F6 board for sale .

30 USD + SHIPPING

So, I've got a 506 CD player and I'm wondering what I should do with it as I don't play CDs any more. Thought I'd ask chatGPT and this is what got. Which I thought was fascinating and somewhat scary at the same time. Can't help but be impressed, particularly with the bit about S/N starting 2 & upgrades...

what DAC chip is in a Meridian 506 series CD player?

The Meridian 506 series CD player uses a proprietary DAC (digital-to-analog converter) module developed by Meridian, rather than an off-the-shelf DAC chip from a third-party manufacturer. The specific model of the DAC module may vary depending on the exact version and year of production of the 506 CD player. Meridian has not publicly disclosed the specific DAC module used in the 506 CD player. However, Meridian has a reputation for developing high-quality proprietary digital audio technologies, and the 506 CD player is widely regarded as a high-end audiophile-grade CD player.

how easy it it to upgrade a 506 from 16 bit to 20 bit?

It is not possible to upgrade the Meridian 506 CD player from 16-bit to 20-bit. The 506 CD player was originally designed and manufactured with a 16-bit DAC (digital-to-analog converter), which means that it is only capable of processing 16-bit audio signals. While it is theoretically possible to replace the 16-bit DAC with a 20-bit DAC, doing so would require extensive modifications to the circuitry and firmware of the CD player, which is beyond the scope of a typical user upgrade.
Furthermore, even if it were possible to upgrade the 506 CD player with a 20-bit DAC, the improvement in audio quality would likely be minimal, as the difference between 16-bit and 20-bit audio is subtle and may not be noticeable in most listening environments. It is also worth noting that the audio quality of the 506 CD player is determined not just by the bit depth of the DAC, but also by factors such as the quality of the transport mechanism, the power supply, and the analog output stage. Upgrading any of these components may result in a more noticeable improvement in audio quality than upgrading the DAC alone.

I'd read that 506 player with serial number starting 2 were upgradeable to 20 bit?

You are correct, some of the later Meridian 506 CD players with a serial number beginning with "2" were offered with an upgrade path to 20-bit resolution. This upgrade was performed by Meridian and involved replacing the original 16-bit DAC module with a 20-bit DAC module, as well as making other modifications to the player's circuitry and power supply.
However, it's worth noting that this upgrade was only available for a limited period of time and may no longer be available. Also, the upgrade may only be available for specific models or versions of the 506 CD player, so it's important to check with Meridian to confirm if your specific player is eligible for the upgrade.
If you do decide to pursue the upgrade, it's important to have it done by a qualified technician who is familiar with the Meridian 506 CD player and has experience performing this type of modification. Additionally, it's important to carefully consider the cost of the upgrade versus the potential improvement in audio quality, as the benefits of upgrading from 16-bit to 20-bit resolution may be relatively modest and may not justify the expense.

what sort of price does the 506 sell for in the UK?

The price of a Meridian 506 CD player in the UK can vary depending on several factors, including the specific model and version of the player, its condition, and whether any upgrades have been performed. As the 506 CD player is a discontinued model, it is sold primarily on the second-hand market.

Based on current listings on various UK-based online marketplaces, the price of a used Meridian 506 CD player typically ranges from £500 to £1,500, depending on the factors mentioned above. Prices can also vary depending on the seller, so it's always a good idea to shop around and compare prices before making a purchase.

It's worth noting that the availability of the Meridian 506 CD player may be limited in the UK, as it is no longer in production and may be difficult to find in certain areas. Additionally, as with any second-hand purchase, it's important to carefully evaluate the condition of the player and its components before making a purchase to ensure that it is in good working order.

I wonder how much inductance is in typical headphone. Say a 32 Ohm device. Or other.
Somebody must have possibility to measure inductance.
Do you know?

so i'm currently looking at a Marshall re-issue plexi from 1987 that has been hacked by someone attempting to make mods and remove the effects loop, needless to say i've had to rewire much of the pre-amp and replace a tube socket (someone cut a plate pin from the V1 tube socket) and replace missing components in order to get back to original but encountered something that i can't account for...now with the pre-amp volume controls fully counterclockwise there's still signal....i've lost my mind investigating grounds to no avail so am left wondering if this is normal??

I'm working on the DIY Sony P V FET OS2 P CH output stage. I,m missing the R8 resistor at 27K does this resistor have any special characteristics

A friend has asked me to adjust the intonation of his Jazzmaster. Turns out it has screws with heads that need an Allen key. The required size is about 2mm or maybe 1/16 inch. Does anyone know the exact size? I don't really want to drag the guitar around the aisles of the local hardware store to see which size fits. Picture of setup below.

https://static1.s123-cdn-static-a.com/uploads/6485140/2000_62bb4e2baf6e2.jpg

I am looking for a vintage amp or a vintage looking chassis for a project lamp for my listening room. Must be not worth for restoration as an amp as I will gut it.

Yes I said that, I want to make a "lamplifier". I have a couple of Manley Snappers that have a cool glow but need a bit more illumination for certain listening times.

I'm hopping to build a lamp with some edison style bulbs (dimmable, wifi controlled) to illuminate the front of the room.

I'm thinking of using the knobs for switch and dimmer (volume).

Have tried eBay but have not found anything I like.

Ok

I admit i haven't been the most active member since 2016 😛

I'm still here... And i would like to send a private message and i am being treated as a "NEW" member





So... Do I have to make some random post's (how many?) to show that i am a human being,
or some ADMIN can fix this? Or is there another solution?

I would really like to send a private message to another member.

Cheers

I saw that the correct size for PR is twice the sub size, but as I want a minimum box size, I wonder if I can increase the total surface of the PRs, in order to reduce the box size, bellow the recommended size for the speaker characteristics.
I plan to build a sub with a Dayton Epique E180HE-44 with it’s associated PR HE180HE-PR.
could I put 4 PR (One on each side of the box)?

Ok folks, in honor of the man himself, Mr. Nelson Pass, I am offering this space heater for free - all you have to do is be a bona fide fan of The One and Only, and come pick it up locally in Vancouver as this thing weighs around 100lbs.

So what do we have here, well this is a decommissioned & repurposed VFD with a very high quality tubular fan added to push air through some truly enormous heat sinks. I won't hazard a guess at exactly how much power you could push through this and still keep the gain stages at comfortable temperatures but I bet it is a lot. The top layer of this beast is the CLC power supply full of big caps, inductors, bridge rectifier diodes (some fancy soft recovery ones if I recall correctly) and a monster toroidal transformer. At a guess there is probably $1,000 or more in parts here before we figure out the heatsinks.

This would be a great winter space heater for one of Nelson's Class A designs - Nelson you brought me a lot of joy over the years - this is my way of saying thank you.

Tell us why you deserve this and it's all yours.

Cheers

(Didnt know where to put this - ended up in fullrange as those are the drivers used)

Link to an interesting youtube video by Dave Rat on stereo/hifi reproduction and why he thinks it still falls short: Speakers Don't Sound Real, Lets Build One That Does
The demo uses a, multi-mic'd, guitar played back through four fullrange speakers; all pointing in different directions.
(His, practical, methods might make some of you shudder, but, you cant deny, he has an infectious curiosity for all things sound related)


I think he has a good point about how things are/can be recorded vs how we, try to, listen and recreate the original enviroment... What do you think?

The floorstanding T-M-M speakers I'm building are 8-1/2" wide by 10-3/4" deep by 44" high, and sit on a carpeted concrete floor in the lower level of our home. I was planning to add four spikes to the bottom of each somewhat top-heavy speaker to penetrate the carpet and increase its stability.
I see that many people place little metal cups under speaker spikes, presumably to protect the floor. Wouldn't these just eliminate the value of the spikes?
Also, I've read that using spikes increases speaker cabinet vibration. I'd assume this is a bad thing in most circumstances, but does it all come down to the room and personal taste?

I have started building the Pass PLH project but stumbled on Papa's suggestion to make P2 a 2-5W trimmer resistor, which part is suggested for this. I can't find trimmer resistors this high? Also, what about R6 wattage? is it OK as a 1/2w or 1W resistor?

Also, can I use 27V power supplies like in the JLH version? Is there any mods I have to do to use lower voltage supply?

I noticed that many (mostly vintage commercial) TL speakers aren't stuffed with a damping material but lined instead with something like acoustic foam or polyester mat. Usually this lining occupies about one half of the cross section, may be a bit more. So my question is how does it change the development process? I may want to try a polyester mat (the stuff used for like winter jackets) as it just easier to work with. Can I just average the density over the cross section? I rely on Hornresp if it matters.

About 18 months ago I purchased a pair of Jordan eikona 2 drivers. Just before I was about to start making some sawdust I had to move house which put the whole speaker project on hold. Fortunately for me my new house has something that I've never had before, a workshop. My original speaker plans had been for a pretty ordinary box as this was as much as I could manage with my old set up. With the space my new workshop offered I could get really creative. A complete redesign was required. The house move presented many other projects that needed to come before the speakers such as new equipment racks and wiring mains electricity to the workshop.
I have finally got to the point where I can start making the cabinets. I have the design sorted, and have made the jigs and tools that will be required and have received most of the materials.
I'm planning on splitting the thread into two parts. First off I'll describe my design decisions. Then I'll document the actual build.

My design goals are to achieve the best possible sound quality (of course) and to make something that visually wows, not by being over the top and garish but by being beautiful. I don't have the largest listening room so they are going to be stand mounted and reasonably compact.
I think my design should achieve these goals.

First installment to follow soon.

Niffy

I love tuners. I've got several of them, including receivers. This time I decided to recap my old Mission Tuner. It's been built in 1985, April 20th to be precise (thanks to Mission folks who identified this on the PCB). Why did I do that? Because it's 36 years old, and the blue Philips caps are not known to last forever. Also, I noticed that it's going wrong sometimes, not able to keep frequency or signal, whether cold or warm (alternatively). So I thought that I could see what's around and detect potential problems here at first.

The PCB is quite simple to get out, I won't insist on this. Always take pictures before, and use some small paper sticks to remember where the wires go.

Taking the electrolytic caps apart and measuring them (twice on 2 different devices), ALL blue Philips were out of specs. Really out (like 2µF instead of 100, or ESR > 40ohm...). The only one that was good was a small yellow Nichicon (probably an old repair).

Good news, as it is a quite simple job to do. Hoping that it will be enough.

Having taken out all of them, I'm now able to make a comprehensive list (BOM) that I post as a picture down this page. in case it's useful for someone without unsolder them all before ordering. There could be some small differences if the model is different, of course, but I guess it should be near the values on this list. Of course, would anyone need the xls file, just ask.

I post a picture of the PCB once all electrolytic caps taken out, so one can see where they take place and which values they are. I wrote values on the picture at the exact place where you'll find the caps.

I'm waiting for 680µ/16V I had forgot to order on my first try 😕 to finish the work. While I'm waiting for the parts, I've decided to repair the small issues (broken plastic lugs as usual on the Mission apparels, cleaning and solder reflow where necessary, maybe a metal cover on top of the HF tuner section if I find some adequate piece of steel in my small recycle mess...).

I'll post pictures of the final condition if after all that, the tuner is OK.

Thanks for reading, I'm happy if it can help someone.

If I had a heavy duty (HC3200) RCF amp that is rated to 110v, would there be an economically viable way to change it for 240v input? Assuming there isnt a switch on the unit ive missed! I read somewhere its a transformer based amp, whether thats the same transformer, in any case it sounds like it might not be so simple...

hi everyone

I'm looking for a very good woofer that can go low in a enclosure of 150liter of even smaller.

I was planning on using my eminence omega pro 15 but they dont go low enough in 150l so im looking for alternatives:
I require about 98db eff driver to mate with my pr170mo and hivi rt2h ribbons
so far, the best via simulation is the:
Beyma 15b100

I wonder if im missing many other otions

any help would be great
thanks

SOLD

Selling assembled and tested Miro's AD1862 DAC. You need to provide additional AD1862, operational amplifiers such as LM6171, as well as power supplies. It was bought in this form here from the forum. It works great. The asking price is 75 euros + shipping.

Just thought I'd give these a try, they've been sitting on my shelf for years. MSP were an Aus manufacturer during 50s-70s
These are their 8TAX/15 Alnico full rangers, 8", 15 ohm, Fs 50 Hz, Qts .84 power 8 watts.
Plonked them in a pair of 30 L test boxes, well stuffed.
How do they sound? - Low end, a bit recessed, but not bad; Mids- low treble pretty good, full & well balanced, but no high highs to speak of, sound OK with a couple of piezo supertweeters. Saxaphones sound glorious on these.
If anyone in Western Sydney wants to try Alnico Full-range nostalgia, come & get 'em, they're surplus to requirements here & need a good home

Anyone figured out which FETs they used on this card? Thanks!

i have no machine for measurement so i ask here

Good evening,
I have a Orion XTR1400.1D.
It was in use for maybe a year. I bought it new but not in the box or at least told it was new.
The batteries on my truck died and I assume they killed the amp when it was boosted.
I have been reading as much as possible to figure out what to test.

It’s very obvious that the transistors blew up. Smoke/smell/burn marks. I had no output but the amp had the light on but not the protection light. No fuses blew it has 4 30 amp fuses on the amp.

I attempted to replace and they simply blew up again.

I am going to order more but would like to not run in circles replacing random parts. It’s obvious they were defective.

I have another amp that functioned torn apart to replace one of the potentiometers on it and am trying to use it to compare readings.

I think I have a dead short in the amp somewhere as I have continuity between positive and negative terminals and my other test amp is not like this.

None of the capacitors are swollen. I have tried checking the transformer for shorts and can’t seem to find anything wrong.

I have a soldering iron, soldering pump, I just ordered an oscilloscope should be in the next couple days.
I have a multimeter as well.
I’ll post a picture of the blown up internals tomorrow when I get a second.

I would appreciate any help

Hello all

Need some help here...

Got this amp last week, good cosmetics, it worked ok. I decided to check bias and DC offset. DC offset in left channel was 8 but it responded well to the pot correction. Right channel was 20, and with pot all the way counterclockwise it went to 10, and that was it. I have to match and replace input transistors I know. I ordered them.

Bias was 16.5 mv at R88 both channels. I adjusted it to specified 33, but other mosfets were all over the place, from 18 to 45, so I turned it down to about 25. Same in left channel. It worked like this for a couple of days, and then - kaboom! Blew both 10A fuses in right channel, and thermal protection LED came on. I found four shorted output IRF244s: Q99, Q92, Q13, Q2. I have no idea what happened...

So, a few questions:

1) I was using outboard turn-on strip, with amp's power switch in ON position - could that do it? Worked fine on all my other amps over the years;

2) Does this amp have a turn-on/turn-off disconnect relay? Because in my case sound comes on as soon as turn it on, and continues for a few seconds after I turn it off;

3) I have located IRF244 mosfets, albeit not cheap. What else should I check for before I plug them in, put the amp on my variac, and pray?

Thank you
Mark

Hello all,

I made some years ago a tower speaker with a side woofer. The woofer (SAL SRP2530 - Kevlar membrane ) is working more like a subwoofer an is cut at ~140Hz.
The tweeter is BS26ADC-C000-4 and for the mid I use Alpha-6A. Crossover frequency are 140Hz and 1600Hz. It is a ported box and I measured -6db@45Hz and -10db@37Hz. The woofer box is ~37L without speaker.

There is a better woofer/subwoofer to work in this box and to not be expensive? Preferable to be available in Europe.

Hi guys,
I've been working on a small boombox based on TD7396 chip.
using 4 Ohm dayton ND140 for lows-mid in parallel with 8 Ohm dayton DC28F-8 for highs.

The system sounds quite good but not as loud as i expected ( and intended, it's a boombox after all)
I checked consumption with a bench power supply, and it draws 640mA @ 14.1V so around 9 watts for a steady 100Hz sinewave

The chip datasheet says that for 14V power is 20W for 4Ohms or 32W for 2Ohms.
As my load is about 2.66Ohms : 1/(1/8+1/4), i would assume to be in the 27ishW. Instead of that, i'm not even at the rated power for 4Ohm !
Chips were buy from farnell, a reliable electronic retailer, i don't think those are fake

What am i missing ? Do someone has any ideas ?

Hello,

Been collecting subwoofers, and the time has come to uncollect them. For pickup only in Los Angeles because they're bulky and heavy, so shipping is a no-go. Photos included are not mine but are representative (except I don't know where the grille is for the Dynaudio subwoofer).



Have a Dynaudio BX30 12" ported studio subwoofer. As far as I know, the amplifier is fine and the driver is not. It's one of the fancy 4" coil Dynaudio drivers, but it looks like the spider gave out, as it's the floppiest thing I've seen this side of [delicious] silken tofu. Big 76 liter cabinet with a large port, 140 watts RMS output @ 8 ohms amplifier (because of the large cabinet, doesn't need much power). $93 firm, pickup in Los Angeles. PDF attached or at: https://usermanual.wiki/Dynaudio/BX30.1158802585/html

Sonance 12-250 home subwoofer. Very nicely finished in piano black. Dead driver, open coil. Otherwise nice, aluminum cone, woven lead wires, big magnet. Really nice - front mounted controls, but behind the grille so they're invisible. Would be great with any nice 6 - 8 ohm driver (low Qts probably better to take advantage of the cabinet volume). $67 firm, pickup in Los Angeles. https://www.sonance.com/product-archive/92365


Exodus Audio PR18 18" passive radiator, cast frame, super well made, with mass kit: $40 firm. PDF attached of specifications.


Squeezebox Boom - very cool Squeezebox-based digital audio streamer with stereo biamplified speakers with a sliding dynamic EQ. $63, this one can be shipped.

Cheers,
Tal

I am considering the purchase of this caliper:
https://www.amazon.com/dp/B018D9JPPA/?tag=best-digital-calipers-20&asc_source=browser&asc_refurl=https://www.bobvila.com/articles/best-digital-caliper&ascsubtag=0000BV0000130907O1400072020230206080612
Anyone have experience with it? Anyone have a suggestion for a better one?

I have two of these, new and sealed:
https://diyaudiostore.com/products/diy-biamp-6-24-crossover

I don't even remember why I have these or where they came from, but someone else can have them for $50 shipped CONUS.

Hi all,

I am getting output signal on the secondary ground. Resistance between primary ground and rca ground is in Meghan ohms.

SOLD Working board fully populated with standard kit parts, including Korg tube and additional capacitance multiplier board (allo.com serial number SBC01-027-001, which could be easily disconnected). No power supply or connectors or volume control. $66 plus shipping ($10?) to USA only.

SOLD

Hi, I have a new pair of EML 30A tubes for sale. I purchased the tubes 3 weeks ago and really not my cup of tea. Looking for a new home. Fielding reasonable offers.

For sale a pair of RACAM amp at 150euro + shipping

For sale an ACP+, EU only, 100euro + shipping

Hello,
Did someone tried these headphone SE output transformers?
https://www.aliexpress.com/item/1005004775304356.html
Looks promising I think.
Thanks,
JG

SMSL SA-98E with TDA7948E chip that sound very nice...non-stock power supply. Works great, need to unload some stuff....

How's $75 + ship?

I have a 50ASx2se I have built into a ghent audio case and I wanted to know if this board here that I received by accident can be used with this as a Buffer. Its aOp-Amp pre amp board. It only has one Op Amp. DO I need a buffer with dual opamp? I am running the icepower single ended RCA and plan on going just output of my Dac to the icepower. If I can use this do I go from RCA input to the input on the board and then from audio out to the 7 pin connector input on the icepower?

Hi so I've got a number of 10" drivers available to me at the moment and I'm trying to decide on the best boxes to build for them. The intended purpose is to replace the current reflex subs I'm using for my function band (Thomann Pyrit 12A - 96 litres) with something a little more efficient and just because I'm interested in building some subs with the drivers that I have and seeing what you can get out of a small box with a small driver. So really the criteria is as small as possible and as efficient as possible. 50Hz-160Hz ish. 40Hz is probably unattainable without an excessively large box and I can always build some THAM15 or ROAR/Paraflex for some 15s I have lying around if I need something bigger. The portability and weight factor is a fairly big thing because I need to transport in a Vauxhall/Opel Zafira Tourer the entire PA plus my keyboard rig.

My initial thoughts were for something like double THAM 10s which seem quite driver flexible and are around 120 litres. However after seeing the ROAR designs and in particular something Circlomanen designed on Martinsson's website I'm keen to get some more information about it and similar projects. I've posted the file here, I gather it hasn't been built but I know Circlomanen has built other similar boxes. Have posted the drawing for clarity.

Any assistance welcomed.

Thanks

My project for the winter is to find assistance or start the hunt for a new speaker. I use to own a complete working set for a bose lifestyle 135 home theater set, but unfortunately after a recent superbowl party the receiver got wet and no longer works. I was wondering if it would be possible to still use the soundbar without the bose 135 receiver and use another non bose receiver? The soundbar inputs consists of a 9 pin input, a headphone jack input, and a subwoofer input. Any ideas, or forms that could assist?

Thank you!
(Pictures below)

Hello all!

I recently acquired 5 JBL 2245H drivers, and have been researching what to build with them. So far, building some JBL 4345 clones, and a 2245h sub are what I'm leaning towards.

I would greatly appreciate any constructive advice on the matter.

Thank you.

Hi All! I am looking for advice on a project that I have coming up. I am setting up and building out a DJ and live music venue, and being a fan of horn loudspeakers, got to thinking about building a really big horn sub (or two) into the stage as part of the build. I will need to build the stage and support it anyway, and thought that I could build the supports in a way that would configure the interior walls of the horn. The stage will be 30" tall, and will be 20' across and 11' deep. I would like to have the frequency response be at least -3DB at 20 HZ, but lower would be nice, and I am hoping to cross over to horn based mains at around 60 HZ. The available space will be 2.5' X 11' X 20'. This should be enough room to build two, with the openings being on the 20' front of the stage towards the outsides where the main L and R speakers will be placed. I was thinking I could use DSP on the the horn subs to time align them with the mains. I have a couple of 18 inch subs pulled from a pair of Energy ES-18XL subwoofers on hand, but am willing to buy something else if these won't do. The venue is around 2400 square feet with 11.5' ceilings. Is this crazy? I have been looking online for examples of this but haven't found any yet. Any advice on how best to do this, and opinions on its feasibility would be much appreciated.

Hello DIYers. I am just about to begin my great adventures into DIY audio. Ive been browsing through these forums for many years now and wanting to build my own system for the same length of time.
I am finally going to take the jump and throw all my hard earned cash into something which will hopefully be a great success!
I have reasonable skills with soldering etc, and a basic understanding of electronics, being an electrician for over 20years, but thats big wires and AC voltages, not the the tiny electronics side of things I am about to dive into. The general understanding of how the inners of amplifers, pre amps actally function will be a steep and enjoyable learning curve.

My starting point will be putting together an F4 amp. This may sound like a poor option with the ACA being a simpler beginners project. But why not, the best way to learn is to jump in feet first.

I already have a lot of very simple and maybee stupid questions and advice to ask.. So be prepared 🙂

https://www.stereophile.com/content/chatbots-take-hi-fi-issues

dave

I've observed a few of SLOB projects come to life on here . A few carried to completion , and some caught in the web of "analysis-paralysis", and yet others hamstrung by unobtanium drivers (result of supply chain ripples)

Why did I build this:

1. To utilize the random scraps of cheap poor quality COVID era ply and other wood in my garage
2. To provide a simple to build , cheap, good sounding example.
3. Use readily available woofers with fairly common T/S specs that can easily be substituted in case of future non-availability .
4. 2 way design with easy to work with drivers .

Drivers used per speaker :
mid-woofer: 8 x 6.5 poly cone woofers https://www.parts-express.com/6-1-2-Poly-Cone-Woofer-4-Ohm-299-609?quantity=1

mid-tweeter: GRS 8" planar https://www.parts-express.com/GRS-PT6825-8-8-Planar-Mid-Tweeter-8-Ohm-272-126?quantity=1

The planar makes this design what it is ... it can run as low as 200 Hz (heck .. I ran it full range at low volume and it worked) and has reasonably flat response .

The bass response is good to 50 something Hz with usable response down to between 40 and 50 Hz depending on positioning . Once again, I haven't set up my measurement rig yet .

While this design doesn't hit the lowest octave, it s strengths are that it
1. gets the bass fundamental and mid bass correct , allowing easy subwoofer integration.
2.is crossover friendly .. shouldn't be hard to crossover . This is essentially a Full range - woofer assisted design aka FAST

I haven't got my measurement setup working so for now, I've rigged up a 2 way crossovers at 500 Hz . I've tried various slopes and a bone stock 2nd order (or even a first order) Butterworth slope driver at that frequency sounds pretty good.

Tested with a run of the mill Yamaha receiver (cleaner + less bass) and also a pair of stock aiyima A07 mini amps that I haven't yet had a chance to tweak for more performance (more bass than the Yamaha but a tad less clear)

More to come . I may have to rebuild this with better materials and more attention to baffle dimensions and shape, wing design, rear wave treatment etc .

If anyone is interested in building a SLOb, this is a fairly cheap way to do it .. and not too bad sounding .

Hi all.
Is F5t v2 suitable to drive planar speakers with 3R resistance or is it only good on 8R loads?
Is there anyone who has already done this experience?
All suggestions are accepted.
Cheers

New Build
This will be the third time I have built this amp section so I know it works fine, and is normally very quiet.
I normally don't use a choke but did this time.
But if I ground R1 the amp hums/Buzz very loud along with some whooshy noise.
I tried grounding C2 directly like I have seen done and the amp hums exponentially louder until shut off.
The amp works without this grounded at all as long as the negative feedback is connected.

Test I have done:
All preamp tubes removed, No change.
Preamp section disconnected from amp section no change.
Phase inverter tube removed, hum & buzz gone. Just a normal low hiss
Changed Inverter tube to one I know works, no change.
Grounds test (several points) show less than 1 ohm all the way to the power outlet.
I don't have a scope, but my meter shows less than 2 volts of AC at the power caps. B+ 473
Plugged another amp with the same amp circuit to the same power outlet, with no issue.


Other symptoms:
When turned off the speaker takes a bit to stop making sound (can't remember if that's normal)
The power caps instantly drain almost completely at shutoff. Normally it takes a couple of minutes with a drain resistor attached.

I have had one of these amps for a while and have just finished replacing most of the aged components.

I have though never found a circuit diagram for it on line or seen anything much from other owners.

Anyone have or had one in the past or worked on one?

Hi,

I have been designing.my 2way bass reflex speakers and now they are complete, Proud moment for me 🙂😉, I have checked the frequency response which seems to be ok, however removing all these biases I like them when they play music.
I am stuck at one point here on my winISD model, where it shows me Cone Excursion exceeds limits from 59Hz to 145Hz over full signal power of my amplifier @40Watt. I am paranoid on this as I fear that may damage my dayton speakers at this level. The cone excursion starts to exceed from 10watts of power.
I am attaching the graphs from winISD and need your inputs and opinion how to limit the excursion as I am stuck in the situation. Also I will appreciate any other design inputs good or bad on improving the design.

Thanks folks and look to have your support, help are welcome.!!!!!!

Regards

Cleaning up the mess...

I was going through a box of semis and found a tube of Toshiba 2SC5200N. I needed one for a SLB power supply project, but for some reason bought a tube of 25. 24 remain.

$2 each + ship. Or $40 for all 24 + ship.

Suppose one constructing one integrated amplifier to keep it understandable lets say one P3A and one DOZ preamp
Integrated amplifier no one is messing up between amplifier and preamplifier
so there is one coupling capacitor / DC blocking capacitor in the output of the DOZ and one more in the input of the P3A
can we remove one capacitor ?
only one capcitor between the two devices should be enough
any ideas ?

Anybody ever tried cloning this amplifier? I am planning to make a PCB.
Is the schematic correct?
Will it work perfectly after implementation or do I have to change anything? Also, will it make any trouble if I eliminate the servo circuit from the amp?

Due to unavailability of some transistors, I want use 2SC2073/2SA940 pairs throughout the whole design and 2SC5200/2SA1943 for the output pairs.

Waiting for expert's suggestion. Thnx in advance!!

The easy little kit
Notes-------------------------------------
Ebay link:
(link 1) Two board *stereo* kit TDA7293 Parallel from HappyShop
(link 2) Two board *stereo* kit TDA7293 Parallel from Min9988
(link 3) One board mono TDA7293 Parallel from Happyshop
(link 4) One board mono TDA7293 Parallel from Fly-XY

Power circuit:
Fortunately, the kit came with 220uF power caps for the amp board, which is perfect for clear sound and cool running of TDA7293. This setup with 220uF (or 330uF) power caps assumes that there will be larger power supply capacitance (a real power supply board).

Voltage:
If you push for quality, the Antek AN-3222 transformer is low priced, drops only 2v @13a and has ideal specs for use with TDA7293. If you push for power instead, AN-4228 is about max. However, 25+25vac dual secondaries transformer is typical and that's what I'm using.


Cap values:
I'm changing the 47uF bootstrap cap to 100uF to assist low bass (valid range 68uF to 100uF).

I will omit the 10uF Mute cap (location is right side of the board, near speaker jack) for zero delay.

A highly effective power circuit upgrade is shown at post#30.

Instead of the 22uF FB-shunt cap (which is far too small), I'm using a 680uF 16v cap paralleled with a 0.47uF electrolytic cap for good treble. I'm also using a 1n4007 antiparallel pair as safety clipper to restrict this big cap's discharge to 0.65v. Photo is at post#29

The 105, 1uF box cap is your input cap, but there's other fun options to use, such as 4.7uF (or smaller) Elna Cerafine paralleled with a tiny polyester (to DIY your own low cost blackgate), etc. . . Try some variety and choose which you like.


Resistor values:
The leftmost 22K resistor is Input Load. Valid range is from 15k to 28k. A difference in value can alter the midrange loudness. If you don't need the adjustable feature shown in the schematic with 100kVR||39k, then just use a simple 22k or 25k resistor for input load.

The gain divider is the factory standard 22K/680R and although this will work, I disagree with bad performance that generic values cause. Instead, I would like to use 27K/730R for great quality. If you want quality results, the feedback resistor and the feedback-shunt resistor(s), MUST be placed underneath the board, close to the FB-Shunt cap. The feedback resistor is installed from pin14 to pin2. The feedback shunt resistor(s) are installed from pin2 to FB-shunt cap. It fits easily and shown at post#24.
The above is new text and new schematic. Previously, there had been some problem getting sufficient gain; however, a just-right gain divider setting with resistors direct (not inserted to pcb), and a power circuit update was the combination that got this little amp up to high fidelity.
See assembly photos starting at post#24

It does use a power board:
Due to the power circuit mods for power filtering at the amp board (in the photo attachments at Post#30) we didn't need a CRC type power board, so here's a simpler edition.
(5x3300u caps per rail and a pair of prefab bridge rectifiers is similar but easier.)

See also Bob's power supply

Yes, new content that uses the schematic (above) starts at post#24--previous discussion might not be applicable to the new schematic, so you will probably want to skip ahead to post 24.

Super new at this guys. I pulled apart the crossover and upgrading components. The tweeter had a 4uf 200vdc and I am replacing with 3.9uf 100vdc. Is there any problems with doing so when it comes to VDC. And what's the difference in vdc with tweeters

Hi,
I need for a line stage 2SA1175/2SC2785. What is the best replacement I can buy ? I need about 100pcs/each.
Many thanks
Dieter

Intended to learn simulation, this amplifier schematic comes up. Yes, it's a modification from some schematic around internet. I did use Micro Cap 12 to simulate. The simulation result looks like output power = 21.1W (RMS) and THD is about 0.02% when D1/D2 being 1N4749. The quiescent current for each output transistor is about 975mA, if my simulation is not so wrong.

There is a significant question to be asked here: is this safe to use +/- 19VDC or even +/- 21VDC for NE5532A for listening? because according to NE5532A specification from TI, its absolute power supply is +/- 19VDC.

Is this Class-A BJT amplifier schematic worth a tryout? Do you think there is a better schematic to try? Under consideration of utilizing NE5532A for voltage gain and DC servo, and SC5200/SA1943 as output transistors. BTW, for learning purpose I already used KiCAD 6 to get a PCB layout and routed, about 2.5"x7", not send out for PCB sample manufacturing yet. I know there are so many DIY experienced people around here, that's the reason I am asking. Don't laugh at me.

Wood has gotten ridiculously expensive if you are forced to buy at end user stores. At the same time the quality you get has gone down. At least where I live. Ply wood has large chunks missing in the surface that have been fixed and hollow spots. Noting you can put wax on or clear coat. Fiber board is rough as sand paper, in the past at least one side was fine sanded from the factory. MDF is often so bend, you have to re shape it for weeks until you can use it.
I have an alternative, that may be interesting for some DIYS guys here.
Since I have a low priced circular saw with a long guide rail for cutting perfectly straight lines, I have started to use old furniture and panels from all kinds of sources for my builds. I collect clean, usable material, cut of the unusable excess and store it.

Lately for example I got 12 doors from an old living room closet wall in different sizes, veneered in wonderful cocobolo. With some careful planing how to cut, I will build a large subwoofer from it.
If you ask, there are always people which are happy to get old furniture or left over building material picked up, as they may have to pay otherwise for it.
Recently I bought a table saw in a close out for 105€, which is perfect for smaller cut's which are more complicated with the guide rail.
It has paid for it self in short time, as I do not have to drive to the hardware store that often anymore.
There is one problem I want to address: Used panels may have screws or nails hidden, which can ruin a saw blade. If you are in DIYS you probably have an electronic line finder. I use it in the metal setting to check before I cut.

Seems like the amp shouldn't power down until the heat sink is pretty warm or even hot to the touch. Any tips?

I have some equipment with a bog standard LCD 16x2.
I built one system up and noticed in one part of the software the display corrupts.
So I checked solder joints etc and it seemed fine.
So removed display and fitted a new one which worked fine.
So bad display ?
I wanted to see if it was software timing problem so soldered bad display into a new pcb.
Now it works fine in the new pcb !

So had a serious look at my software timings and they are all above what spec suggests.

Not sure where to go next ? unless it was a bad solder joint that looked ok ?

A year ago i bought this amp as defective on one channel.
I repaired it and then it has been on my shelf for a while.
Now i will need an amp to drive 2 fronts and 2 rear speakers in my RV (camper)
i will probably use a portable sub together with my setup.
My idea is something like 2 pairs of infinity kappa and a tube sub.
I will not destroy my interior with a big subwoofer.
Question sell the Harman and buy something newer and better sounding or keep it?

Pelle

Hi

have some problems with my vfet,suddenly it lost all power, can hear faint sound when volume to max, same level in both speakers.

it´s not the source or preamp, using them with my f6 now.

i measure the power into the output stages be 33.somthing volt , shouldn't that be 36volt, can this be the meanwell power supply is gone bad

Andreas

Hi folks!


Does anybody have the schematic of Pink Triangle's THE PIP or the PIP 2 ?

I remember listening to the PIP2 a long time ago and found it very good - a phantastic battery powered amplifier with a very unusual look.
I also remember a HifiNews article rewieing this item vaguely ( it consists a transconductance amplifier and passive riaa).
It seems for what reason ever PT discarded the product early, it was no great succes (which does not say anything about sound quality).

Any deeper knowledge ?

greetings
Klaus

Hi all

Some hesitation on adding to the pile of Sony V-Fet threads. So this is aimed at logging MY refurbishment of a Sony TA-5650.

(My TA-4650 thread is https://www.diyaudio.com/forums/solid-state/376634-sony-ta-4650-fet-thread.html that didn't actually go so well)

First of all lets get some resources out of the way (just in case)

Service manual: best copy by far I've found is at hifiengine although others exist they are resolutely monochrome 🙁
Service bulletins: yes! most important is the 'dutch' one as it details mods to bias and component changes made to enhance longevity (Has ANYONE seen that in English?)
Circuit operation: see "Sony TA-4650 new circuit operation" for a how it works document that broadly applies

Other links:
https://www.diyaudio.com/forums/solid-state/311612-sony-ta-5650-restoration-doc-breaths-life.html
What I hope this thread will mimic 🙂

So here goes, as usual I haven't finished this project yet so its not a tale of, "this is how you" it's recorded live 😀

I find it very useful to step away from the project and document it.

I have *TWO* Sony TA-5650 amps and one set of working power transistors
Serial 601467 - marked as 601518 internally
Serial 602370 - marked as 300378 internally

602370 has Grey Elna Caps fitted rather than blue Nichicon ones, as a side note, it is also missing a positive power rail, at least without Vfets

To me it looks like 602370 went back at some point and got a new serial (?!?) Unless someone knows what the internal numbers actually mean anyway...

601467 is cleaner, as both of these are 'pre-loved' maybe it's been serviced, I couldn't tell you. Anyway I'm going with 601467 from here in. A decision that would have been best made BEFORE I robbed the output board for the TA-4650 project.

Can I just say I hate wire wrapping. I really hate wire wrapping.

Andy

Hello everyone. I found a Project Phono Box mm/mc phono preamplifier at a garage sale, the model that is powered by an external 16v AC source.
Since I already have an IFI ZEN Phono, I want to experiment with modifying the Project towards the Actidamp II, just to see how it sounds.
I have found the thread of said modification, but when I look at the circuit board I see that as IC it has TL 071 CP.
I have searched for information and I see that this integrated is not dual.
How could they use it as a dual IC? Or is there a dual version of the TL 071?
Since I haven't bought the transformer yet, I haven't been able to test it, I don't know if it's working.
Another question. Is it convenient to spend time in the modification towards the Actidamp?
According to what I have read, it would be the original scheme of the designer.
Greetings.

Want a giant-slayer amplifier for short money? NAD built the 2600A and its twin the 2700 THX in large numbers. You can find one, maybe with some minor fault that reduces its price to beer-money territory.

This circuit does a lot of things right, right from the factory:

• degenerated IPS
• IPS loaded by a current mirror
• IPS doesn't directly drive either the VAS transistor or the miller cap. It's lightly loaded.
• triple EF output stage
• generous stability margins. (We need this when the OPS rails boost from 54V to 92V when the "power envelope" kicks in, that creates a blip in the output. That blip should settle and stabilize in less than 500nS, healthy stability margins allow this.)

It doesn't sound bad stock. From the factory this is similar to Doug Self's "blameless" amplifier, doing almost as well as anyone knows how to with single-pole loopgain roll-off.

But can we do better? Can we improve its distortion performance by 20db? Will it kill Krells and mince Macs? You know it 🙂


Step 1: This amp comes with a built in preamp, a couple of JRC opamps that implement both the bridging switch and the front-panel volume knobs.

Even a 5532 is better than these opamps. Better yet, just remove R121 and R123 and jumper over them to defeat the preamp and run the "lab input" (aka "THX input") straight into the power amp section. Aaah that's better.

Deleting the bridging support is no sacrifice, as there's NO earthly reason to bridge this amp. With 92V rails, this amp is marginal for a 4-ohm load before bridging -- you're reaching deep into the SOA of the outputs to drive 4 ohms at anything near full rail voltage. Bridging it just makes this worse: 8 ohms becomes equally marginal and 4 ohms suicidal. Just don't.

Step 2:

With a few substitutions, we can convert the factory circuit to TPC compensation. With two-pole roll-off in the loopgain, we can reach >55db of feedback in the audio band, instead of the ~35db we get with the factory circuit. See comments 5-7 and 22.

A word of caution, these PCBs have a very thin copper film. I often use the dremel to gently remove solder mask and clear off some copper, but that doesn't work well for the NAD -- the bit goes right through the copper to the fiberglass! :-C Ah well. If this was the kind of amp whose build quality audiophiles crow about, we wouldn't be hacking it up would we?

Step 3:

Adjust the input network and NFB network for reduced distortion and improved DC balance, see comment #9.


Step 4:

Add filtering on the +18V rail, and improve the IPS current source with an LED; see comment #15.


EDIT: First attachment is the stock circuit. Please ignore the 2nd attachment, which is an older rev of this mod. The "latest and greatest" circuit is in comment #22. Cheers!

I’ve never seen such a big ribbon driver before, nor one with such an extended frequency response. On paper it looks like and option of something close to a FAST system. Of course, there are no THD measurements and I can’t find anyone using them (the pdf is marked preliminary). Are there obvious trade offs with ribbons tweeters trying to go this low?

LM8K - Wide Band Planar Ribbon Transducer - Radian Audio


Brian

Hi all,

I have two potted (epoxy filled) and shielded (Iron can) O-Core Transformers for sale. Both are brand new, and unused.

Originally purchased from James Transformer for a project that never happened....such is the way it goes sometimes.

Transformer Spec:

VA: 50

Pri: 240v
Sec1: 0-18v
Sec2: 0-18v
Sec3: 0-18v
Sec4: 0-18v

Premium quality transformers. Both tested and working.

£65 ea, or £115 the pair. Inc postage in the UK.