[EDIT]: SOLD. No longer available.

Latest (3rd generation) version of the popular miniDSP digital crossover and signal processing unit, "TRS" version with balanced analogue input and outputs, plus mini-TosLink, SPIDIF RCA and Bluetooth LDAC/APTX/AAC digital inputs (in addition to USB, of course).

All specs available at the manufacturer's site: https://www.minidsp.com/products/minidsp-in-a-box/flex

MINT IN BOX condition. Only used once for a system set-up.

250 GBP asking price. Payment by PayPal, or cash on collection.

Located in London (UK).
Shipping Worldwide via Parcelforce approx. 30 GBP.

I'd welcome your opinions on what you think is the best 6-7" woofer for use in a 30L (1cu.ft) 3 way with xover around 600hz?

I'll have 150watts for the woofer.

I currently have these on my radar:
Seas ER18RNX
Dayton Esoteric ES180
Hi-Vi D6.8 ('cos I've got them already)

Thank you!

I saw this on FB.

"Work in progress …. Alpair 10.3 gold transmission line fully inspired from Jordan TLA design

First driver in full range mode

Second driver ( bottom ) filtered around 250 Hz with second order crossover

Plenty of dynamics , full bass response ( not yet measured )

My current speakers : magnepan MG12qr with custom made feets and external crossover"

Is it possible to do this with all drivers? Maybe Alpair 11MS?

Many years ago with the help of people in this forum I built a sub with a driver I had, a 10" which was pretty good.

That sub has been dismantled years ago. And I'd like to build a new one, to go low.

The room I'm running it in is only 3x6 meters so it doesn't need to be ridiculously loud. But I'm trying to find a good driver. The problem is that there are so many of them out there in the market, and I have no idea where to start

How can one tell if a driver is a good candidate? What specs should i look? Is it possible to look at the T/S parameters to quickly discard bad candidates?

Hi there! been a while
A frind carpenter luthier have some little home based studio and he got some speakers somewhere. They are Polkaudio rt55i. he wanted to make a box and he can litterally make any box. Control room is little, like 6x9, but still the box could potentially be big and inside an insulating, non mechanically connected with studio, dry wall.
I took the meassurements, vas method didnt worked out well so had to make the mass one...
Any suggestions welcomed, this are supossed to go in ceiling. Was thinking about a TQWT with new front bafle.
And a question, where would one choose roll off to begin considering TL dB/oct decrease and a little room? like 40hZ?
I was having fun a and then started doing something probably stupid, trying to compensate TL peaks with Difraction peaks. Not sure seems risky... could be adjusted at least in seem, anyway still room response not known

Hey there,

I have this huge 24inch speaker from fane laying around since quite a while and I always wanted to build an enclousure for it.
My main problem is that almost every design I could think of is using way more space than I am willing to sacrifice.
I‘m thinking that with a sinple closed box I‘m just not using the whole potential this driver is giving but in order to get a well playing ported box I need more than 1000l to really play below 30hz.

I would be super happy if anybody has a Idea on what enclosure is fitting this speaker the best.

My goal is to have a box with a volume around 500l total to use for watching movies and listen to some music.
I want the sub to play from mid 20hz up to at least 80hz.

The TS prameters are:
fs: 21hz
Re: 6Ohm
Qes: 0.54
Qms: 4.1
Qts: 0.48
Vas: 980l
Vd: 3.8l
Cms: 1.7MNx10^-4
BL: 17.1Tesla
Mms: 316g
Rms: 11Ohm

Thank you guys!

Hi,
do any of you have the Thiele & Small parameters of the Focal 5N302 loudspeaker?
I enclose a photo of the speaker.

As the title says, I'm on the search for information about coaxial drivers. I'd like to get a better understanding of the characteristics of the different types. And is there a design that is better than another?

My current speakers use a coax driver with a separate HF wave guide for the coax dome tweeter. Then I see there are also coax speakers use the woofer cone as the wave guide for a dome tweeter. And there are coax drivers that use a compression driver.

I am playing with the idea of adding a coax driver to the project I'm working on (home stereo, sound quality prioritized over spl). If I choose a coax driver, I would be looking for a 6" to 8". The coax driver would be for mids/ highs, and it will be crossed to a 12" woofer at around 300hz.

Is there a particular advantage to a coax driver using a compression driver for HF? I don't have any experience with horn speakers in hifi speakers, so I don't know what to expect. I've heard people discussing that the HF wave guide in front of the mid driver causes distortion, depending on the size of the wave guide. And people talk about how cone excursion is a problem when using the woofer as the HF wave guide.

I'd like to hear what you guys have to say on the subject.

The objective here is a pro-sound sub useable from 40hz upwards, with a net volume somewhere around 10 cubic feet.

The driver is a Planet Audio FU18, which is a clone of the old Cerwin Vega Stroker subs. It's a dual two ohm voice coil, so the power plot is really 2 watts, but I think the efficiency is pretty good anyway.


I anyone has the inclination to have a look at the Hornresp file, it would be very much appreciated.





Layout will be pretty well like this picture, but the upper chamber will have 4 ports passing through to the lower chamber to symmetrically load the woofer. It's an old speaker and I don't know that it has the strongest cone int he world. Two ports will simply be holes cut in The 17mm plywood used for the build for ease of construction.

I have 2 CSS SDX10 subs that have open voice coils but are otherwise in great condition. The woofers move freely and the cones and surrounds are in in excellent condition. CSS said they can't repair. I'm looking for any suggestions for how I might repair or there is a repair shop that might have a voice coil that would fit before I throw them out.
TIA,
Jim

I was furnished a pair of Burson Audio V6 Classic opamps to evaluate. The deal is that in exchange for the evaluation pair of opamps I try them out and post my impressions here. So here we go...

1. They work. No issues in my simple opamp-based 2-stage phono preamp (input opamp > passive RIAA EQ > DC coupled to output opamp). Voltages check out, it plays sound.
2. The only objective feature I can give you right away is DC offset.
   • The previously used opamps are LM4562. With those in the preamp, the DC offset at the outputs is 2.1mV in one channel, 1.3mV in the other channel.
   • With the Burson V6 Classic opamps, the DC offset is very slightly higher: 2.1mV in once channel, 2.8mV in the other channel. Since the V6 Classic has a JFET pair input, I'd expect its DC offset to be higher than that. It did take a half-hour or so for the DC offset to come down from about 10mV shortly after power-on.
   • The DC offset was much higher with a pair of OPA2134, but unfortunately I can't put those back in now because they're now installed in a different preamp. I did try OPA2134 in this circuit first, but saw almost half a volt DC offset, decided to try LM4562, and wound up settling on those.
   • So... The V6 Classic opamps have notably lower DC offset in this circuit than OPA2134, and only slightly higher DC offset than LM4562.
3. As far as my subjective impression goes, the V6 Classic opamps sound good to me in this particular circuit, for whatever that's worth. Maybe the V6 Classic sounds a bit 'warmer' or 'rounder' than with the LM4562 in circuit, but I suppose that's not surprising since many have described the perceived sound of LM4562 as more 'detailed', 'analytical', 'clinical', etc. than other opamps like OPA2134, etc. Any differences are subtle, as you would imagine. I figure THD levels from any reasonable opamp are going to be so low as to be inaudible, so one should expect any differences to be small, unless something was seriously wrong.
4. Physically, the package is super-easy to install and remove from standard DIP8 sockets. It's very friendly for those who wish to 'roll' opamps. You're far less likely to bend pins inserting or removing these Burson V6 opamp packages than with a standard dual inline 8-pin opamp IC.

For those who care, the system used consists of a rebuilt Thorens TD124 turntable with Audio Technica ATP-12T tonearm and Audio Technica AT-VM95ML cartridge, into the preamp described above, into a passive selector switch and stepped attenuator, and finally to a pair of JBL LSR 305P active speakers. The listening room is small, about 4 meters wide by 8 meters long by 2.5 meters floor to ceiling.

I hope that helps someone. I'll report back if I have anything noteworthy to add.

Interested in building some enclosures to run some tests.

Sealed Enclosure (Sphere) 1.25 cu.ft
Egg Shaped Rectangle 1.6 cu.ft staggard with a 3" port 7" long below it.

Testing some builds to try and accomplish flat response across entire bandwidth 20-20khz possible thinking of using a passive radiator to assist the driver.

Please Advise ......

TX

What types of connectors are reliable and suitable for the umbilical cable between a power supply and a low-power device, like a phono amplifier or DAC?

I'm trying to use the line level inputs of the WM8731 and the "Absolute Maximum Ratings" below was confusing to me:

As can be seen, the datasheet says the absolute minimum for analog inputs are AGND(0) - 0.3V = -0.3V whereas a line level input could swing to -1V. I also see a lot of projects just using the line inputs on this chip disregarding -0.3V. I see on the datasheet and it definitely works. So the logical conclusion is that I'm missing some obvious knowledge. Could anybody explain?

Best

Hello all,
am new to the idea of using a preamp, always thought I could get away with a volume control on the source and directly go into the power amp. However, lately I dabbled using the preamp section of a Yamaha AV1 receiver between source and power amp (ARC VS115) and it has a bit more "foundation" with it. SO now I am infected with the idea of getting a balanced tube preamp and really intrigued by this chinese clone
Hi End AudioResearch ARC Tube Preamplifier Balanced/RCA IN&OUT,12AU7/ECC83+ECC88/6DJ8 Preamp DIY Kit|Amplifier| - AliExpress
There are many questions just arising from the text (it can be found on ebay as well, but the pictures on this ad are better)

Assumptions:
1) the coupling transformers are to connect unbalanced inputs and process them as balanced
2) the rectification and voltage regulation is included (board and part-wise, except the EZ90 tube)
3) hard time finding a transformer fitting the requirement 280V (two sides), this one is quite close 80W pure copper R-core transformer for tube preamp / phono 280V-0-280V +6.3V *2 | eBay
would one get away in connecting the 2nd 6.3V circuit in series to the first one to tap of 2A @ 6.3V and for the series connection 12.6V at (2A, instead of 3A)?
4)not familiar with preamp topology...no need for an output transformer???
5) a quick search would have the total cost for board, transformer, tubes at 335 US, worth it or better get something what looks like the finished (copy)?
12AU7 ECC88 Valve Tube Bile Preamp Pre amp American ARC Circuit Tube HiFi Balanced Bile Preamp Chassis shell/finished machine|Amplifier| - AliExpress
for roughly twice the price
6) I am really interested in building a kit this time (it has been a long time since I did something in the amplification world)

What are your thoughts? Have you build one of these clones yourself?

Cheers
brxl

I‘m not sure if this is the right place to ask, but:
The plastic part of the power-switch of my old audiolab 8000P broke apart.
Since they‘re nearing their 40 years, many probably get discarded or cannibalized... so, maybe... has anyone a spare powerswitchbutton, or knows of someone having those around?

Pls PM
Thanks very much...
David

I'm working on an upgrade modification for this GFP-750 preamp. Once the cap portion of the upgrade was installed, I noticed I had no right channel when the unit was out of passive mode. I've checked components, traces, solder joints, and voltages. Some of the voltages are off on the right channel, but I can't figure out what is causing them to be off. Any help would be appreciated.

Had these for about 8 years. *They do NOT have crossovers, front grille and misc. parts. They are wired to be actively amped. To best of my knowledge, all drivers are OK. Free to haul away. I'm about 1 hour north of Tampa. Please message me to arrange pick up.

It's probably unlikely to lead to anything, but in case you have a Silent Switcher you do (no longer?) need...Any feedback will be appreciated - thx.

Hi,

Not sure if its the correct forum, however, does anyone recognize these components? "CCB" 745. This at the output of an DAC, so i am guessing this is may be some protection diodes(maybe 15v zeners?) but they where arranged a bit different than expected. SOT-23 package

Dynaudio Esotec 15W-75-4 Ohm woofers and D-28 tweeters

As on photos, speakers are 100% flawless working in IMHO in great shape. ( Other than back-foam on woofers has disintegrated and was removed..like on all of them). Both woofers measure 3,3 Ohms ..and tweeters 5,4 Ohms/DC resistance.

Asking for 260€ plus shipping for all 4 speakers.

Regards, Davorin

I just received my T34B tweeters today and got all excited to open them up and admire the fine European craftsmanship, but what i found instead was a back chamber of a driver had come off in transit. The other one still was intact but I only needed to pry very lightly and it came off as well.

The problem is they glued the chamber onto the polished and plated surface of the magnet asy. The magnet surface isn't rough enough to adhere to the adhesive they used so it can get a good bite on it. Needless to say I'm not impressed. At least you guys can see what these things look like inside. There is a 35mm disc of wool felt for dampening inside the chamber. Nothing fancy. I swept both drivers without chambers and they both sound fine, so I'll glue to chambers back on again.

Very disappointing. I thought the Germans know what they're doing with this stuff.

http://buildaudioamps.com/project-3/

Hey forum people,

Does anybody know weither the line, marked by a blue line, is correctly placed? Should i put a GND wire under it?

Question 2: Is the power inductor as in photo left upper corner, the right choice ? Is there a difference between axle and no-axle?

Greets, Wouter van Wegen, PascalByThree

Having SB20FRPC30-8 & Wavecor wf182bd07(4Ohm). Currently using the wavecor in a 2 way with the wavecor tweeter TW030WA08. Would be cool to make a MLTL - But also don't want it too big (wife friendly) 😊 "Don't have PC so can use those fancy programs I read about a lot are using"
Regards Tomas

From symmetrical to asymmetrical using the Fibonacci series.

In self-construction it is advantageous to use asymmetrical parts instead of symmetrical ones. When choosing measures I have a habit of choosing values from the Fibonacci series to avoid having parts with multiple measures.

In my latest MDD3ZC350 V2 prototype I improved the detail of the reproduction by moving the base supports from a symmetrical to an asymmetrical configuration and repositioning the force application points. The use of asymmetrical parts can also be advantageous in other projects (frames, stands, racks, ...) by reducing the possibility of triggering spurious vibrations.

In the first version of the MDD3ZC350 prototype the supports were at the vertices of an isosceles triangle (central figure – 3 symmetrical supports). The position of the supports divides the 340 x 340 x 20 mm plywood base into four sections (a), (b), (c), (d) with mirrored shape and constraints in pairs. The vibrational energy that can be stored in section (a) is the same that can be stored in section (d). The vibrational energy that can be stored in section (b), is the same that can be stored in section (c). More or less damped vibrations can be triggered both between sections (a) and (d) and between sections (b) and (c). The subsonic mount bracket was fixed in the center of the underside of the triangle and facilitated the triggering of unwanted vibrations.

In the second version of the MDD3ZC350 V2 prototype the supports were at the vertices of a scalene triangle (figure on the left – 3 asymmetric supports). The position of the supports divides the 340 x 340 x 20 mm plywood base into four sections (a), (b), (c), (d) with different shape and constraints. The vibrational energy that can be stored in section (a) is different from that which can be stored in section (d). The vibrational energy that can be stored in section (b) is different from that which can be stored in section (c). Vibrations can NOT be triggered between sections (a) and (d) or between sections (b) and (c). The subsonic mount bracket is attached close to the top mount further reduces the likelihood of unwanted vibration being triggered.

In a base with 4 supports (figure on the right – 4 symmetrical supports) there are four sections (a), (b), (c), (d) with the same or specular shape and constraints. The vibrational energy that can be stored in section (a) is the same that can be stored in sections (b), (c) and (d). More or less damped vibrations can be triggered between all pairs of sections. If there are problems, the configuration can be transformed into an asymmetrical one with 3 supports by adding a fifth support slightly higher than the others in asymmetrical positions. The material to be used can change according to the system and the floor in which it is used, it can be rigid or yielding, elastic or inelastic.

The use of supports in asymmetrical positions can be useful in self-construction where design systems with simulations that directly control the vibrations of the parts are not used. If a symmetrical system is well designed, with no vibrations, switching to an asymmetrical setup will bring no benefit.

Thanks for the attention.

So I've been DIYing and I'm wondering, is it ok to keep ground wires from different signals connected?

For example #1 I'm making a simple XLR A/B box, and I'm not sure if I need a three pole switch or if I can use two and keep ground wires from both inputs connected to the output.

#2 I have two TRS inputs and 2 TRS outputs, and I'm gonna use a switch to split sides or keep them stereo. If the switch is on, TRS output #1 will only out merged L sides from both inputs, and #2 merged R sides, and when the switch is off, both stereo signals should just pass through. It's the same situation, do I need a triple pole switch, with the 3rd pole being used to disconnect grounds while not splitting sides, or is it ok to keep them connected at all times?

Just been daydreaming about speaker builds, and thought I liked the look of Visatons, because they're cheap and have have pretty neat Frequency Response charts. Until I go to calculate the enclosure and they come out freakishly huge. Like, 200 litres for an 8 inch woofer (W 200 8). The 6.5 inch version has a qts of 0.81, and a similarly sized cabinet. I was scratching my head for a bit, wondering if the datasheet was wrong, until someone mentioned 'open baffle'. So does that mean you can either stuff them in a smaller cabinet and ruin that beautiful flat frequency chart, OR just rely on your room to do that for you? The other thing that comes up is a lot of people seem to like them for replacing 'vintage' speakers. So i guess in a small enclosure they're kind of a bit lazy, warm, quiet - good for the oldies? They do have a bit of that aesthetic to them. They don't have that aggressive kind of garish 'Lamborghini" kind of design language that others go for.
That said they have these 4 inch FR speakers that look great for satellites or bluetooth speakers. I haven't quite looked at their 12 inches - but I'm thinking those would actually work quite nicely in a guitar amp?
Interested in anyone's experiences with them
https://www.soundlabsgroup.com.au/p/V-9063-W170/W+170+-+8+Ohm
https://www.digikey.com.au/en/products/detail/visaton-gmbh-co-kg/FRS-8-M-8-OHM/9842306

Hi, i have had stability benefits in all op-amps by soldering a 100v orange philips type capacitor (suitable horse size) directly on top of the + and - pins.

Hello, I have a question that runs in my mind about crossover freq, we have the usual passive crossovers low pass/high pass 2.5khz , 3, 3.5 ,4 etc, and active with a knob from 250 to 100hz for low pass on car amps for example.
Let's say we need a high pass filter for our tweeters let's say at 3khz ( active or passive doesn't matter ) , now if we look at the musical notes frequencies , closest to 3khz we have :
if we look for 3.5khz we have:
3520hz which is closer to 3500, we use 3500 instead of 3520 for "easier manufacturing" component values ? or why.

Is there a difference if we cross over at 3khz or cross over on the " exact note freq " at 2959hz ?.

, Bruno.

I have an 'old' radio in my truck (2001 ram) that won't find any stations, won't play stations manually tuned, and if saved in memory and retrieved will 'play' but be full of static. Its kinda unique, for whatever reason, as in i haven't seen a picture of another one on the internet so far (there is one craigslist post of the part number, but thats it). Plenty of other models of radios (i have 2 others) for the 'same truck' (anything from like 1970-2002, trucks, vans, durangos whatever), just not this particular one. I've been hoping to fix it, instead of just replace it, both because of the 1.5 din size and uniqueness and then stick a bluetooth module in the thing probably on the CD lines to modernize it just a tiny bit. Are there some tests i could do to narrow down the FM issues? I assume its not the truck, as i have 2 other radios I've stuck in the thing and both work just fine with the same hookup, one being as old and one being a tiny bit newer (and its taken a swim).

This is the face of the radio in question. Part number P82301040.



I replaced it with this one (from a donor truck) when the tuner originally died (its been a while). One day the volume knob died and this whole project got kicked in motion. Turns out a rotary encoder in it had the backing/detent disc shatter. Simple fix, right? Get another Alps EC11 encoder with a threaded body, 4mm slotted shaft 30mm long with button. Apparently this is not a thing that exists (anymore? or because the manufacturer bought so many they have a custom part?). So instead i got the cheapest 15 position 30 detent EC11 i could find and hoped for the best. Opened it up and took the disc, stuck it in the old body and it works fine. Sadly, this one was flooded at least once in my yard and the CD player doesn't work, even though it takes and ejects CDs, the CD motor spins when forced and the laser motor seeks if moved out of place. In practice it never spins up (wired in leads to spindle motor and checked) just throws an ERR and splits out the CD when you try to play. Since i had planned on intercepting the CD lines for the bluetooth thing this is also technically broken for me. And its ugly, though it was uglier. It had amber LEDs on the balance knobs. Those were just slotted in, so i removed those and its slightly less ugly now. But its also not unique... this seems to be one of the most normal radios for my truck (I think the version that looks like this but also has a cassette is the most normal one). So instead I still hope to fix my original radio.

Donor radio face, part number P04704373AE.




I kept looking all over for even a bad picture in a scrapyard of my radio on the hopes of just mixing parts to make one working one, still haven't seen another example in the wild. Its the internet, how can there be no other examples of this anywhere? Widening my search i came up with a few more radios with faces more like my original. Fairly common to see a cassette only version like this: Cassette only on Ebay. Then some more strange ones that don't appear on lists of radio options for my truck: No cassette only on Ebay. No CD only on Ebay. Weird stuff. But this last one, no CD but otherwise very similar face to mine also has an identical(?) plug layout, and i saw a cheap and clean one up for bid and got it on hopes of the board being a de-populated version of mine. No such luck there. Here is the clean face of my 'new' radio. Looks like its almost never been touched...

'New' radio, part number P04704360.



And now for the guts. The boards are very obviously quite different, but it does look like the tuner section is fairly similar. Maybe i can compare them to help find faults in mine? The new one does work in my truck, while the old still doesn't, Also note the date code, i assume, on the big chip at the bottom 95 48. Which is a bunch older than my 2001 truck. A big bunch. As far as i know its the original radio though. Original radio board with CD.



'New' radio without CD. Date code on its big, but different, chip is 94 52, so a fairly similar vintage. Also so darn clean. No idea what this is out of to be this clean.



But the cans are probably the same. So yay? Maybe? Or do the supporting tuned thingies need tweaking to make it work so its basically hopeless? Original can.



'New' can.



I have temporarily run out of knowledge though. I can do electronics to some extent, but i know nothing about voodoo, err radio. I do think that can has something to do with it. No idea if that is whats broken. So far testing voltages on the two boards seems close enough on all the pins of the cans that i would say it should work, if it works, or i'm not supposed to get voltage but something fancier and i don't have the tools to measure it.

I did have another thought here as i got the very clean 'new' radio. I don't actually care about the CD player. Only wanted it for the bluetooth module to splice into and play silent CDs with phone music instead. This is how i had read others having done it, either with cassette or CD. Seemed like a fun project to 'modernize' without actually going for a ugly modern 'solution'. But, would it be simple to splice into the AM source instead, before the mux which i assume is somewhere (haven't really gone down this path yet) either breaking the traces from the AM source completely or putting in some switch that does it. Then i could have the 'new' radio play FM normally and hit the AM/FM button would swap to bluetooth. I assume the board doesn't care what the source is doing on the AM side unlike the cassette/CD side, where if it doesn't play it won't stay on that input.

Fun little project so far even though i haven't done much.

Following my experiments with the modular power amp https://www.diyaudio.com/community/threads/rcp130-modular-lateral-mosfet-power-amplifier.368795/ where I gathered knowledge regarding several types of input stages I finally chose the mirror loaded complementary symmetrical IPS described here: https://www.diyaudio.com/community/threads/slone-amp-final-solution.379346/

When using a symmetrical complementary IPS loaded with mirrors we face ourselves with the typical problem: “the VAS input voltage is not defined by any reference voltage, so it depends on the VAS base current and the Early voltage of each transistor connected to that node, as well as the common mode offset current of the LTP.”

To circumvent this problem, I added a 1k resistor (R12) between the emitters of the top CM (Q10) and VAS bjt (Q3). Fig 1


Fig 1 (R12 action)

According to Keantoken, R12 works actively by converting the VAS and CM into a CCS (analogous to the standard 2Q CCS).

As I see it, the current in the CM is perfectly defined and produces a voltage drop across R2 (Q10 emitter degeneration 133ohm).

R12 transfers this voltage to the emitter of the VAS Q3 so a fixed current runs through its degeneration resistor R11.

NOTE: R12 can not be replicated in the lower VAS (Q5) because that way both positive and negative VAS would try to fix a current in the bias spreader and due to differences in NPN PNP transistors, the current would never be exactly equal… (Both VAS currents would fight each other).

As is, R12 fixes the current on the positive VAS and the negative VAS just follows as if loaded by a CCS.

Another benefit from this configuration is that OLG is not severely decreased as in the case where both VAS currents are regulated.

Lowering R12 value increases VAS current stability but lowers OLG. The 1kohm was chosen because it represents a good compromise between current steadiness and High OLG.


Fig 2 (New circuit OLG plot)

-------------------------------------- NOVELTY DRIVEN CASCODE ------------------------------------

I chose to cascode the input jfets because when the cascode is “Driven with output signal” it does minimize voltage fluctuations between the sources and drains of these JFETS.

This “constant voltage” approach can effectively reduce higher order harmonic distortions.

In my prototype, the voltage divider that sets the cascode base voltage Fig 3 (R37 R45) is modulated by input signal through the connection CCSP…. While this method works, there is always a small current diverted from the Jfet sources to the voltage divider and Input Jfets Vds is not really constant.


Fig 3 (Prototype driven cascode circuit)

In my new design Fig 4 I chose to drive the cascode bases through a NFB replica coming from the output signal.

In this case the negative feedback replica circuit (R59 R60) modulates both positive (Q7 Q8) and negative (Q12 Q13) cascodes, through the bases of the followers (Q19 Q20).

This way, by carefully choosing R60 value (1k98 ohm) I can stabilize the voltage between the Drains and Sources of the IPS JFETs.


Fig 4 (New Cascode drive circuit)

Looking at Fig 5 I placed two test points: JD on the Drain and JS on the source of input jfet J1.

When running the simulation, we see that JD sits at 9.572V and JS at 98.6mV

Plotting V(jd)-9.572 and V(js)-98.6mV we see clearly that both curves are coincident and by tuning R60 we can actually null the difference.

Here we see 542uV Vds voltage variation @ 1KHz 290W.


Fig 5 (Input Jfet Vds plot)

Viewing the results of the .four command Fig 6 (1Khz 290W), we observe that THD is minimized when both curves are coincident.


Fig 6 (1KHz 390W FFT)

I hope this new method gathers enough interest to produce a fruitful discussion on how to best “drive” both cascodes simultaneously.
To facilitate analysis I am including and .ASC file that can be used for testing.

All models are included in the .ASC file so it runs directly in LTSPICE.

This simulation is initially set to produce 300W into a load of 5ohm @ 20KHz

You can choose other values by modifying the values of:

.param power=300

.param freq 20k

.param rload=5

Control transient is:

.tran 0 {{delay}+(20/freq)} {delay} {timestep}

DISCLAIMER:
The present schematic must not be used for commercial purposes.
This is can only to be used as a DIY project.

Need some help guys. I broke down this sub yrs ago & forgot what model its is. I've searched everywhere but cannot find a Sundown with this basket. It is possible it was swapped but wanted to check here first. It's a 12" with dual 2ohm coils. I need to recone it but dont know model or where to get recone kit. Any help would be much appreciated.

Hi, I have an old Primare A20 that’s been working fine for many years. Recently it’s started to hum through the speakers. The noise sounds like ground hum and is there even with no inputs connected and doesn’t vary with the volume. The sound is the same through both channels. I’ve checked and all the ground connections are fine. Is there a particular component that could cause this issue?

Just discovered these recordings on the White Album Super Deluxe. Never knew they existed. Like the Beatles Unplugged. Anyone know what microphone Harrison had in his Esher studio?

I'm working on a line array design that will go behind an acoustically transparent projector screen. The original idea was to use six 6.5" drivers and six Neo8 planars. But modeling in WinISD, and test speakers showed more low-end drop off than I was hoping for. So now I am considering changing the design over to a 2.5-way design; running the six speakers directly behind the screen upto 550 Hz, and the speakers that would be behind or below the projector screen only upto 80 Hz; hoping that the omni nature of the lower frequencies will not give me horrible diffraction artifacts off the projector screen frame and any other gear that happens to be in front of the speaker.

I am leaning towards having all 12 of the 6.5" drivers share a common rear chamber tuned to Q=0.707. My thinking is that as the frequencies rise above 80 Hz that the effective Q of the enclosure will shrink (because the low frequency drivers will be 15 dB down above 200 Hz) - improving impulse response. Is this a bad idea? Do 2.5 way speakers need to have the low frequency driver(s) in their own enclosure for some reason?

For six of the 6.5" drivers:
Q 0.707 = 6627 in^3
Q 0.577 = 16,100 in ^3 Almost 3x the volume required!

First DIY amp build. Got four NC500MP modules, planning two put into a box: https://uk.farnell.com/metcase/m550...250mm/dp/1510826?CMP=e-email-sys-orderack-GLB (for a total of two boxes). Also planning to design a pcb (block diagram attached) to perform auto signal sense, and mute on startup, 12V IO. What do you think? Any tips of advice? Thanks.

Wonder if anyone has come across this before, I just got one of these caps:
https://www.mouser.com/datasheet/2/40/ffve_ffvi-3162691.pdf
and it came with a dot marked by one of the terminals. Does anyone know if that indicates a preferential polarity, an outside foil or whatever? There is nothing written anywhere about it.
I noticed larger capacity Solen PP have a + indicator as well. Should that be taken as the preferential plus or high impedance side connection?
thanks!

I'm working on an upgrade modification for this GFP-750 preamp. Once the cap portion of the upgrade was installed, I noticed I had no right channel when the unit was out of passive mode. I've checked components, traces, solder joints, and voltages. Some of the voltages are off on the right channel, but I can't figure out what is causing them to be off. Any help would be appreciated.

This driver has a cone that appears to have been an available replacement cone as seen in the Harmon Kardon images as well as being an exclusive clone for Brociner speaker drivers. It is in very good condition. DCR is good but there is a slight cone rub. I inquired with Lowther about re-coning this and they quoted approximately 800 euros (before Brexit) for new cone, re magging of the motor, and an updated basket design. I’m on the east coast and can deliver within 200 miles of nyc. The cabinet is solid but cosmetically poor. I will provide any and all info within reason. Asking $3200.00.
Open to reasonable offers. I’m selling this driver, which I will likely never have enough money to buy ( I found this one)
due to financial calamity. BTW, I’ve been on EBay for 20years 100%. Handle is Shokujitsu.

So I have this Memphis car Audio PR 1 × 1000 class D monoblock amplifier that I got from a buddy of mine and as soon as I turn the amp on, the protect light turns on. But after checking on my wires making sure that they were connected correctly the weirdest thing happened, when I would reconnecting the blue remote turn on wire to the amplifier, the light is blue for a few seconds then turns red as soon as I tighten down The wire... So I pop the top cover off the amplifier to further inspect it, and noticed there's these metal plates with three prawns that are rusted/ burned up. What are these connections and is it repairable?

Hi Everyone,
I have a problem with my Denon AVR-5803 and am hoping that an expert here can help me troubleshoot it. This receiver turns on for a few seconds, then turns off and the power light blinks quickly (twice a second). Any help will be greatly appreciated!

Considering eval1 for purifi amp, but it will have to fit with other amp modules for a 6 channel amplifier.
This will got into a custom case with speakon and xlr cutout.
I see the eval1 has solder pads for speaker output, so I don’t need to remove the jacks.
For the xlr, there is nothing indicated. Can I get the signal from wire soldered underneath the board or should I remove the xlr sockets to solder wires to my chassis sockets?
Thanks!

Hi All… UK expat based here in Singapore.

This is actually my first post on diyAudio… so please forgive me if this is in the wrong section or if the attached pictures are too big... or even if this post is a little lengthy.

OK, I’ve been reading and gathering as much information as I’ve been able to first, prior to posting. This is having come across a Threshold S/350e power amp locally, for sale.

Due to the age of these amps, I know it’s de rigueur to replace the power filter caps, change the tantalum to an electrolytic cap on the FEB, check (de-solder) and/or replace any output transistors that may have failed and replace the carbon composite resistors due to drifting for something more appropriate… amongst others !

However, before I effectively go ahead and purchase this superb amp and “go to town” on it, I’m by no means an electronics “guru”, but I know enough to refresh these amps and perform upgrades etc. So, would appreciate as much feedback or suggestions as possible from others members on here… and perhaps, if the man himself, Mr. Pass, would be kind enough to provide some additional enlightenment.

The following is what I plan to do, so far…

• Replace power filter caps; any recommended value… or is it just a case of the largest value, lowest ESR and highest ripple relative to correct voltage and physical size that will fit ?
• Replace base emitter resistors with Dale NS Series (non-inductive) 1% 2.5w wire wound; any alternative type recommended ?
• Replace (C7) 4.7uf tantalum with electrolytic; low ESR recommended or alternative type for stable and long life ?
• Replace (C4) 220uf electrolytic; low ESR recommended or alternative type for stable and long life ?
• Replace (R37) 6.2Ω 1w carbon composite; any alternative type recommended ?
• Replace (T1) trim pot with multi-turn type for easier adjustment from top of amp; any thoughts on this ?
• Replace (C7,C8,C9,C10) power supply pcb (small) electrolytics with low ESR types; any thoughts on this ?
• Add bypass caps to power filter caps; any recommended value and type ?
• Fit a soft start circuit; any recommended brand ?

Also…

• I’ve read somewhere on the internet but it wasn’t explained how, the balanced input impedance can be raised from 600Ω to approximately 50kΩ; any thoughts on this ?
• Replace (Q5) 2N5566 with IFN2N5566 I’ve read it is/can be beneficial to replace this JFET; any thoughts on this ?
• I understand a matched pair of IFN2N5566’s is required for the above point; any thoughts on this ?
• I’ve read about one member; kevd having significant trouble some time ago trying to bias his amp which eventually turned out to be an incorrect CNY17-4Z optocoupler instead of a CNY17-3. I understand the FEB on these amps have (U1,U3,U5) three (3) CNY17-4Z optocouplers; do all three (3) need to be replaced as per component list, or just U3 adjacent to the trim pot ?
• I’ve seen pictures of the (C12) 0.15uf/400v replaced with a WIMA polypropylene; any thoughts on this ?
• Considering the idea of replacing the rectifiers with pcb modules utilising SiC Schottky diodes mounted on heatsinks; any thoughts on this ?Based on experience working with PA systems, I know all too well in general it takes more “energy” or power to drive the LO end, compared to the MID’s and HI’s. So this is what I have in mind at the time of refreshing this amp; my plan is to keep this amp as standard and run it Class A/AB @ 150w per side for the moment. Then, if I purchase a second amp, reconfigure it to an SA/3.9e and run it Class A @ 60w per side for driving the MID’s and HI’s, while using the first amp and run it Class A/AB @ 150w per side for driving the LO’s… this is to allow for “headroom”.

Hopefully, the overall above configuration will be a good match for driving a pair of B&W N804’s @ 89dB, which are notoriously current hungry and a fairly difficult load to drive down to 3Ω.

Perhaps an additional thought to allow closer location of each amp to each speaker without having to cross any of the cables etc., a more intriguing or adventurous idea would be to create a pair of S/350e “hybrid power” amps, using the existing double bridge rectifiers in each amp.

Looking at the schematic, mount a second transformer in each amp with a centre tap (how would this work with both 31v & 50v taps ?) two split the power filter capacitors using a custom sourced pcb then reconfigure and bias one side to run in Class A/AB @ 150w for the LO’s and the other side to run in Class A @ 60w for the MID’s and HI’s… would anyone like to enlighten if this is doable somehow ?

Other suggestions or input is welcome and greatly appreciated.

TIA… Phil.

Hello everyone! I was wondering if you could help me out.

A while ago I took on the challenge to build myself a quad NAD 3020 power amp with an ESP 4 way crossover, and a NAD 1020 pre amp. Without tone section, but with the 1020/3120 high level pre-out. Which would make this a NAD 1120 if you like. I know I do 😉
Clone power amp and PSU PCB's I purchased from Scafas.
I also bought a Chinese clone of the pre amp, but I thought it would me more fun to make this myself.
And so it began...
This is the first time I am making a PCB. A challenging task I must say!
After a lot of time fiddling around with Circuitmaker I came up with something I think I'm happy with. One channel only for now.

I really don't know if it's any good. Could you shed your light on this design for me please?

• I copied the circuits from the service manuals and more or less followed the original PCB layout
• I took the original NAD3020 pre amp section (with the benign crosstalk error). Rail voltages +29,9V and - 25,6V
• ripped out the tone section
• added the 1020 hi level pre out. That one runs on +-20V.
• and hooked them up together, using the rail voltage of the 3020.

Questions I have:

• is it possible to increase rail voltage on the high level pre out from 20V to 30V without changing resistor values? (R5xx)
• Could you check on the value of resistors R541 and R539? I think I might have muddled this up.

PCB version with and without Gnd plane added, for visibility tracks on back layer
Thanks a bunch!

The 4066 4PST analog switch is widely used in vintage audio gear, but is notoriously BAD, both in THD and on-resistance. Analog Devices has a new switch out that is vastly superior---the ADG6412. It DOES require an adapter board to drop it into the 14-pin DIP footprint of the 4066, but a clever fellow has made some available in this thread:
https://www.tapeheads.net/threads/adg6412-possible-new-4066-replacement.103635/

Hi All!!

I am trying to have some fun with op amp swapping with an old bose 901 equalizer series IV. I also have a series III which is fully discrete. The series IV euqualizer came with LF353, pretty bad. I mounted machined socket so I could swap them. I then installed RC4558, bad highs, super harsh. I moved to TL072, improved things, smoother, but loss of volume. Changed to NE5532, getting better. Do you have any other suggestion to mount a "better" opamp? I included schematics of one channel.
Thank you!!

Just went thru a huge post on the LM3886 and a few on the TDA7294 on fake chips. With batch numbers which are not legit.
This seems to perplex a lot of people. When I built my first TDA7294 amp. The chips I got blew up the second power was connected.
Not being able to find original chips I found some which was marked Made in Singapore.
These worked. They were pushed to the chips power limits and it did not fail.

So here is my take on fake parts.
They are what we call in India backdoor parts.
I first ran into this problem in 2002 when I launched my first Digital Ignition. Only to find people were selling digital Ignitions for 1/10th the price.
So a year was spent trying to solve this problem.
These units were all stamped just like the original factory units. As part of my investigation I even purchased a few and opened them up. To find they were legit.
Finally just as I was about to give up. The mystery was resolved for me. These back door parts are stolen. Either from inside the factory or while in transit from the factory to OEMs.
Theft of chips and electronic circuits is a multi million dollar industry. To avoid being tracked its a very common practice to file off batch numbers and just replace them with garbage.
The first guy in the chain got the parts for close to free. He then files off the batch number Prints something different on it. And then sells it to re-sellers for 1/10th the price. The re-seller than marks it up by 100-200% and sells it to the customer.

Just thought I would share this story. It fits perfectly with what we are seeing happening with fake transistors and parts.
In fact goto any whole sale market in any major city and you will see them taking delivery of large consignments with no paperwork.

This is rampant in countries like China and India. And in the USA on ebay.
Stolen parts go for about a cent on the dollar. When purchased from the first guy. The final re-seller makes about 100-300% margin.
When it comes to other parts like Caps. They have a time expiry date i.e. if they are not sold in x months after manufacture their values fall. And they are unfit for regular sales channels so these also get dumped for cheap on the market.
There are guys who rebrand a similar IC or a poor quality IC but the numbers are small.
If you want more info on this look into the stealing of ICs and the volumes that are stolen every year.
I have seen both types i.e. crappy / wrong products rebranded. And original items rebranded.
There are many legit chip companies that do this on the side.

Hello!
I am trying to use hornresp for Tang band w1772 in the horn Jericho and SUG1. Can anyone help me to get that?
Settings in hornresp.

Im trying to understand why the designer of this amp. Used these components on the Phono Input.
He has soldered the following components between the Phono in to ground.
To the positive pin he has soldered a 47K resistor. At the other end he has soldered a 4.7K resistor to ground.
Between the Positive and the negative he has a 3K3 ceramic cap. When I enter this up in the simulator it shows a drop of 10% in the input signal.
But there must be a reason for doing this. After looking at hundreds of Phono sections I do not see anybody else using this.
The 4.7K to ground seems rather low. Most other designs use 100K to ground.
Have included a pic.
Should I mod this or leave as is ?.

Dear all,

I have been working on a little CLI tool which makes it easy to create a config for Henrik Enquist's amazing CamillaDSP.
I am mainly into headphone listening so I wanted to have a solution to quickly create a config with EQ correction data from Jaakko Pasanen's wonderful AutoEq and also add different crossfeed presets.
Maybe the tool is useful for someone here. That would be great!
Since CamillaDSP is more and more integrated in RaspberryPi based audio solutions like moOde the tool can also be handy in that use case.

This is it: https://github.com/Ebert-Hanke/autoeq2camilladsp

I am happy to hear what you think about it. Also if someone has more in depth knowledge on the specific DSP implementation of classic analogue crossfeeds I would be happy to hear it.
Thanks!

Cheers,
micha

I came across a Triaxiom 212c mounted in a diy enclosure. It was teamed with a Decca Kelly DK30R ribbon tweeter. The triaxiom is in pristine condition except it is missing the horn on the coaxial tweeter. The DK30R requires a new ribbon so I can understand why the enclosure only cost $20.

It seems the original owner had simply used the triaxiom as a woofer only and had removed the horn from the coaxial tweeter. The tweeter tests ok so I was hoping to find a junked triaxiom somewhere in order to buy the horn. If anyone is able to assist I would like to hear from them.

I am in need of a replacement ribbon for this speaker. Does anyone know who repairs the ribbon holding plate?

I would highly recommend anyone with novice to intermediate repair skills to get Perry Babin’s repair tutorial. I’ve been doing car audio repairs for a few years now, but not having any formal training, I was pretty good at simple repairs, but nothing really deeper than blown outputs or bad switches.
I recently got an updated version of Mr. Babin’s tutorial and started to seriously study it. I had 2 amps (a JL Audio E6450 and a Power Acoustik TS1920 Plasma Sphere) that had been sitting for over a year with bad power supplies that I could not figure out. Within 2 hours of studying the power supply section in the tutorial, I fully understood how the P/S works, and how to test the driver IC. The very next day, I got into both amps, and found the problems on both amps within 30 minutes. Ordered the parts, got them today, and happy to report that BOTH amps are now working. If you are SERIOUS about learning how to fix amps, don’t hesitate to get his tutorial. He has a free website that will give you plenty of info and a basic amp repair tutorial. https://www.bcae1.com/
Check it out!

When calculating the volume of a line source enclosure, is it just a case of taking the required volume for one driver and multiplying it by the number of drivers, or is there more to it?

Thanks for reading!

Hello all.

I am currently trying to troubleshoot and repair a W200 Sub as a personal project/learning and it seems to have gone a bit beyond my circuit knowledge having exhausted most of the obvious testing (attached images blue=tested, yellow=replaced). A repair had been attempted by a family member prior and some of the tracers damaged so I had to repair them first.
The board is a 104-A05426B00V-E and is an ICE3B0365J chip, and after finding the chip datasheet have gotten the following readings;

1.SoftS - Unreadable (fluctuating)
2.FB - 473mV
3.CS - 0
4.Drain - 330V
5.Drain - 330V
6.n.c. - 110mV (fuctuating)
7.VCC - 15V (fluctuating)
8.GND - 0

I vaguely understand what each pin is for, but I'm not sure what values I should be expecting in order to trace where any extra voltage is being lost, or being gained. I am assuming the Feedback voltage is too low so it is cycling restart, but I might be misunderstanding the datasheet. The transformer secondary is not receiving any voltage at all which I assume is due to the VCC not being stable.

Any insight into this would be very much appreciated.

XHello everyone. Can anyone help me look up SMD components with code 6J as shown in the picture. This smd trandito is in the DAC circuit of the Marantz 6007 CD. Does anyone have the service manual for me, please?

I have newly aquired a used 27.5 and need to adjust the Bias on both channels .
I have the schemtics and some description of the circuits , I think it is R114 which does the bias adjustment but not sure what should be the voltage acrosss Emitter resistor points... in my previous ML29 amplifier it should be +26.4 millvolts

Thanks for any help!

Georg

I would like to achieve 100wpc out of a no-feedback class-A design. My first thought for achieving this was to run my BA3 as a bridged mono amplifier and build a second one for the other channel. Is this possible? It's been a couple years since I built it, and all my knowledge seems to have dripped out my ears.

Hello I been going through some bags of parts and found this bag with approximately 200 transistors, all new, but what are they?

Dipole drivers for sale new, never used:

BG NEO3W planar: with shallow back cup (one pair has back cups removed, but included) 4 pairs available, $150/pair
BG NEO8S planar: double magnet high output version, 2 pairs available, $250/pair

AE Dipole 10: 2 pairs available, $600/pair
AE LO12 D8: 1 pair available, $650pair

add shipping from NY, USA

I constructed my best DIY high end Speakers using multiple constrained layer damping to build a woofer enclosure that is far superior, a audio muffler design for the midrange and unique dipole multi position tweeter. The speakers have a unique vintage but modern design and can be converted in a compact version with amazing sound.

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I have an ADVANCE ACOUSTIC. MAA 406
The amplifier goes into protection after a few seconds.
After a few tries, it sometimes manages to stay on.
Can someone get me started?

Here is the schematic of the PA 7 nakamichi amplifier
Noticed that the LTP doesn't get any feedback from the output
Can somebody explain why ?
can somebody comment that in terms of sound quality ???


After that there is couple of more questions ....
in basic terms and except the feedback thingy this shares similar principal of operation with the ESP design p68, at least for the output schem.
Now Rod in his article suggest this amplifier for sub woofer use since there some concideration about crossover distortion or poor freq response , even though it is clearly stated that he didnt notice anything while listening to the amp .
So i wonder if a similar problem applies for the PA7
Then again there is a bit of wierdnes in the design since the amount of outputs is pretty high for 60 V rails .... I understand that this apmplifier with that ammount of outputs will easily drive any load regardless of the speaker impedance .
In the PA7 i also notice fairly hi ballast resistors 1R that also is a question

Thank you very much

Any recommendations ?

Hello,

I started using Moode Audio a few years ago and was always blown away by the difference between a dedicated Pi Streamer (with moode at that time) and my normal desktop pc... this is also where my "audiophile" jorney kinda began, things in the OS and on the hardware seems to really to matter
And while Moode Audio is a kinda good out of the box expierence, it really lacks the ability to be customized (you can do it but updates could break things you changed for example and there is always a limit of how much you can do and stay combatible with existing things)

I also looked at Volumio... but it never apealed to me, specially since i also heard the worse SQ as many others people reported
SqueezeBox/PiCorePlayer also never really appealed to me but i actually never tried it, i just never was a fan of LMS since it looks and feels kinda outdated

I recently started using DietPi (after trying to run Arch Linux) and i think its one of the best OS bases for the Raspberry Pi 4, you stay completely in the official "Raspberry Pi OS" realm but with benefits that DietPi brings via minimalizing the OS and their scripts
I currently just use the DietPi OS to use the raspberry pi 4 as "Audio Gadget" and CamillaDSP to route the audio from usb input to the dac output (this also sounds better then going directly from PC to usb input of the dac, this way you can also use RPI4 hats and use the RPI4 as "DDC" for your PC, which will be one core feature of this custom os)

Soo... now to this thread, while it would be great to make a own streamer os image from the ground up and share it with others this is way out of my comfort zone, so what i actually wanna do here is document my journey of tweaking the dietpi os to my liking and needs, so other users may get inspired or even try to help build with me the perfect streamer OS

i wanna document each step so that it would be easy for others to actually replicate the exact OS im using (well and for me in case something goes wrong, haha)

So what goals do i actually have?
1. being able to use the raspberry pi 4 as DDC for your PC
2. use the raspberry pi 4 as standalone player (basicly what moode/volumio does) for possibly best quality (tho from my tests using the RPi4 as DDC isnt far off if not identical!)
including for example cd support and dlna support
3. keep the OS as minimalistic as possibly
4. try to find the best software for each "step" (for example one huge step up for me was using linear phase EQ inside EasyEffects instead of other IIR solutions like CamillaDSP)
5. tweak the OS itself for better SQ (for example underclocking the RPI4, maybe trying realtime kernels later and so on)

i did got some inspiration by "GentooPlayer" and one thing that really intrigues me is the script-server, it could be used to offer install scripts (and other things) of the software i use to make things way more userfriendly (install dietpi, install script server, get my config files and go from a nice web interface 🙂) this seems way less hassle then building a own OS image too i think

What you guys think about this? would some of you interested in such a custom OS ?

New TDA1541A DAC D/A Converter NOS (non-oversampling) module replaces SAA7220B filter and includes muting function for CD players.
$70 each plus shipping. PayPal only. 2 are available.

Sold "as-is" and no warranty is expressed or implied. No returns or refunds. Sells and ships to USA residents only.

Hello evertone.

I am trying a copy of a simple Zobel network and can't seem to identify this component (the small white one in the picture) I assume it is a small value resistor, but I have never seen one like this before? It's secured to an Ohmite WH series 5W resistor. I have all the other components to hand so I am going to breadboard and see how it works at virtually no cost, but would love to know what the stange white component is.

Thanks!

HELLO........I HAVE A AUDIO PROCESSOR NAME:-R2A15218FP RENESAS AUDIO PROCESSOR--[8 CHANNEL ] AUDIO PROCESSOR.......ACTUALLY IT DOSENT HAVE ANY DATASHEET TO MAKE A CODE FOR THAT AUDIO PROCESSOR.......................................................IS IT POSSIBLE TO MAKE A CODE FOR ARDUINO..............................PLEASE I AM TRYING A LOT TO DO THAT PROJECT........I WANT HELP.........CAN YOU HELP ME...... AND I FOUND A LITTLE ABOUT FEAUTRES FOR THAT PROCESSOR DATASHEET

I have spent quite a lot of time experimenting with several modes of i2s connection, grounding and wiring and here is the final conclusion that I came to:
I have experimented with the following 3 methods of connecting converter to DAC via i2s:
1. TTL with only one ground wire and 4 signal wires (data out, lrck out, bck out, clock in)
2. TTL with 4 ground wires running in parallel with 4 signal wires
3. RS-485 using flat ribbon cable
And soundwise the winner is #2. TTL with only 1 ground wire has sound that has a small amount of noise which makes it very hard to listen to for any continuous period of time.
RS-485 sounds better than TTL with one gound wire but it has a small amount of noise as well that is quite difficult to listen to for a long period of time.
Also I want to say that I conducted the following experiment with RS-485. I cut the flat ribbon cable into 4 balanced pairs whereby 1 balanced pair was used for each i2s signal (data out, lrck out, bck out, clock in) and then I twisted wires in every balanced pair. So in efect I got 4 twisted pairs for RS-485.
I was unpleasantly surprised because it turned out that 4 twisted pairs sound worst for RS-485 than just standard ribbon cable. Why is that so, I don't understand.
Another experiment that I conducted was wrapping each balanced pair in a copper tape and connecting all these copper tapes to the DAC's ground. This configuration produced very bad sound with some kind of distortions which are very difficult to listen to. Why is that so? I can't find any explanation in view of the fact that as far as I can see people like to use standard HDMI cables or custom made HDMI cables for balanced i2s and such cables are sold at very steep prices.
Could anyone explain this phenomenon?

I asked the GPT guy, but I don't trust him that much, as for several times it answers dubious or incorrect responses... And I think some topics are somehow biased.

So I wanted to know:
BTJ or JFET?
How accurate are its answer?

GPT:

JFETs in the Gain Stage:

• High input impedance: JFETs typically have a very high input impedance, making them suitable for applications where a high input impedance is desired. This minimizes loading effects on preceding stages and helps maintain signal integrity.
• Low noise: JFETs tend to exhibit lower noise characteristics compared to BJTs, making them advantageous in applications that require low noise performance, such as audio amplifiers.
• Simple biasing: JFETs have simpler biasing requirements compared to BJTs, making them easier to implement in some cases.
• Voltage-driven loads: JFETs have a higher output impedance compared to BJTs, which makes them more compatible with voltage-driven loads such as capacitive loads.

BJTs in the Gain Stage:

• Higher current gain: BJTs typically have higher current gain (β) compared to JFETs. This higher gain can be advantageous in applications where higher amplification levels are required.
• Lower output impedance: BJTs generally have a lower output impedance compared to JFETs, which can help drive low-impedance loads such as speakers more effectively.
• Wide availability: BJTs are widely available and offer a wide range of options, making them suitable for various amplifier designs.
• Cost-effective: BJTs are generally more cost-effective compared to JFETs, which can be a consideration in some designs.

In summary, JFETs are often preferred for their high input impedance, low noise characteristics, and suitability for voltage-driven loads. They are particularly beneficial in applications that require high input impedance and low noise performance. On the other hand, BJTs offer higher current gain, lower output impedance, and cost-effectiveness, making them suitable for applications that require higher amplification levels and driving low-impedance loads.

This same plug is on the MTX Terminator 250. Made by PPI. I have one and love it and still use it in my vehicle, running 400 watts mono into two subs. THe issues the that amp and this one is that samn Molex connector for the speaker wire, etc. Is there now a better way to replace that? Mine is sporadic and i temporarily fixed it by putting a nickle squeezed in beside the plug and working so far )this put the needed pressure on the plug I guess.
What's the easiest way to replace this today? 5-way binding post? What will work?

I am looking arround to low frequency transducers like Focal Audiom 15ax.
Especially the values for Vas (635 L) and Cms (the driver's mechanical compliance = reciprocal of stiffness, in m/N) so as Qms are exceptionell large and the resonance frequency f-res is very low (22,8 Hz). This value is by the use of cloth surround instead rubber very noteworthy and an indicator for a very low weight (mass) of the diaphragm (cone).
All this features saves an unparalleled combination of clean and tight bass so as a very low bass at the same time, if the camber volume is appropriate therefore.

Drivers with similar parameters that I know are the follow:
- Cabasse 55ND
Cabasse haut-parleur 55ND
- HKM XX-21
(formerly WESTRA/TESLA, see attachement)
- 2x McCauley 6258
McCauley.com : Products: Components > 6258: Specifications

Unfortunately the Cabasse 55ND is too expensive and the HKM XX-21 has to strong variations between the individual devices.
From the McCauley 6258 I use two pieces in one chamber. Unfortunately in the meantime very expensive in Europe (and amazingly not in United States), now twice as expensive than 14 years ago by German's old distributor "Sirius".

Which additional currently available bass drivers in this size have similar parameters (as close as possible to the Audiom 15ax for use in large cabinets, i. e. VAS between 500-800L, f-res. below 25 Hz and Qms above 10)?

Thank you for any hints.

One pair. 15 years old. Used. And one is reconed by Kimon Belles of Focal 12 years ago.

Rims are a little beat but everything seems to work and sound fine.

95.5 dB/W/m
Nominal Imp: 8ohms
DC resistance 6ohms

$399 plus shipping. Paypal only. Thanks

Many a PCB cad appears to be going over to cloud and subscription, wonder why that is, Eagle comes to mind, going over to Fusion and a subscription being asked for, is this a good or a bad thing?

I've been using Labcenter and was looking for something a little better.... no wonder I couldn't find Eagle, kinda leaves their users in a lurch if they start asking for a monthly fee.... I myself would avoid Cloud based CAD like a plague so that means RS Design Spark and others is a no. no for me, what do other folks think here?

As time goes by my choices seems to dwindle.

Dave

Another project I will no longer pursue...I bought these drivers for a Pluto type Speaker years ago...

(2) Aurasound NSW2-326-8AT 2" Tweeters
(2) SB Acoustics SB16PFC25-08 6" Woofers

All never been used - removed from box for these pics.

Buy some PVC Pipe and you good to go...

How's $130 shipped for all CONUS?

Hey all,

Just gutted a Hafler P2400 for the chassis to make my second ESP P101 (sweet!)

So I have the transformer and original rectifier and plug. I do not remember the Rail voltages, but the Power supply caps were 75VDC, so around 65 - 70V rectified.

TT-XL280 is what it says on label, and I believe this transformer was used on quite a few amps...

I will find out exactly what the secondary windings are when I have an idle moment...

How's $60 + ship from Chicago sub?

Tested,functional + symmetrical source with LM317,337. Price 70€. Postage EU included in the price.Very good sound. IO-OPA2134

Hi everybody!!!
I need service manual/schematics of Mark Levinson 334 power amplifier.
Can you help me?
Thanks in Advance.

I came into some Zenith transistors,, if there is a Zenith to common transistor substitution list out there, I can't find it... Does anyone know if one exists??
Putting the Zenith number into the alltransistor site won't do it...
TIA

Hello all, I will attempt a ported sub after successfully building my first sealed sub.

My driver of choice is the Dayton Max X 10-inch. Link: https://www.daytonaudio.com/product...-high-excursion-dvc-subwoofer-2-ohms-per-coil

Power will be supplied via Crown XLS 1502.

I will build the box on Dayton's recommendations of 1.1 cubic feet with a tuning frequency of 28-29hz. Currently, I am having trouble figuring appropriate port configuration.



In WinISD port length is 36 inches when the port area is 4 inches tube, with 24m/s air velocity. Or 46 inches when its a 4 x 4 (16 inch) slot; however it's 46 inches in length. I would have to do a lot of folds just to get that to fit. Then my volume would shrink, so I would need an even bigger box than what Subbox Pro is suggesting.





Using sub box. pro my port is always outside the box. I input the driver as taking up 0.1ft3




The issue is the port is stupidly long, with a port velocity of 28 m/s, regardless if it's a slot port or a tube port. My use case is music, so I would like to keep this at a safe level and not have any amount of chuff or distortion, or audible noise. What Can I do to rectify this situation? I am not well-versed in how certain parameters affect others.

It almost seems that the subwoofer cannot be built due to the required port lengths. I have not even added any bracing yet. Is there a software that works better than box pro that is free so I can visualize it? Would be nice if Subox automatically increased my box size to keep the 1.1 interval volume.

Thank you in advance.