Hi,
I have been working on improving a Philips CD730 (similar to CD920/910). Added spdif out and updated the usual caps.
The unit was working fine but now suddenly only outputs digital noise/garbage on both analog and spif out. I checked voltages to all ic's and opamps and no problem there. Even swapped the opamps (which i placed on sockets) but no change.
Is there anything obvious i am not seeing as a problem now?

Wouter

Can i use the inputs in the red circle in the attached image, to supply 5 Volts from a linear power supply to the Singxer F-1, or how can i do it??

Thanks for you help

I listen only to classical music and opera, and am looking at taking the next step up in speaker performance.

After trying a full range driver approach and realizing that they are not very good for classical music, I moved up to a pair of 2-ways with Jeff Bagby's Piccolos. That was a major improvement over the full range and now I'm finally enjoying the music. However, as good as the Piccolos are, they still don't give me quite the "big" sound that I am looking for with classical symphonies.

So now I'm researching the next step up, and believe that it has to be at least a 2.5 or 3-way. Troels Graveson has two new open SBA Satori designs that particularly interest me.

SBA-761

SBA-741

The SBA 761 is a 2.5 way and the SBA 741 is a full 3-way. Both use the TW29RN-B-4 for the tweeter and the MW19P-8 for the woofer. The difference is in the midrange and the cabinet design. The SBA 741 uses a 4" MR13P-8 for the midrange while the SBA 761 relies on the 6" MW16P-8 for that purpose.

I'm not going to ask which one is better, because that probably can't be answered. What I want to know, however, is what differences to expect in the sound.

Troels discusses the main differences on his website as follows:

With the 761 he says that by mating the MW16 and MW19, the latter gives quite a lot extra power in the lower registers. The combined membrane area is 277 cm^2. And that pays off in not only bass, but also upper-bass and lower midrange, which is a very important frequency range giving volume to grand piano and the cello.

The 741, on the other hand, uses a 4" driver for the midrange, which is much better at handling the upper midrange and lower treble compared to any 6 or 7" driver. The lower treble range he specifies to be ~800-1300 Hz while treble starts at 1280 Hz.

He adds that it comes as a surprise to some that 6" drivers are very often used to handle the treble, although it is very common in 2-way configurations in order to keep the cost down. However, this in a way contradicts the idea of the 761, essentially diminishing its value as an alternative to the 741.

What I am particularly interested in is any difference in the way the two will handle a sudden sharp string attack. When I listen to classical music and there is a sudden attack by the violins, for example, I want to hear a very, very sharp "kzing" and not a dull mushy "zuhm". This might have a lot to do with transient response and the cabinet themselves, so it may be difficult to predict.

Finally, I have two questions.

Which of these, the 741 or the 761, do you think will give me the better "kzing" on sharp violin attacks?

If you listen a lot to classical music, which would you choose? The 741 or the 761.

Thanks.

Hi

Is it possible to setup in CamillaDSP with Moode audio following configuration?
https://www.diyaudio.com/community/...overs-without-measurement.189847/post-6680665

Use the mixer to copy one channel to other for a mono output and then design the crossover within the left and right channels connected to the HF and LF driver of a single speaker.

Propose of this setup will be find best XO for two way speakers. Is it setup bellow OK is it possible to have capture playback channel only 1.

Hi Folks. I have multiple caps for sale about $900 worth of capacitors. They are all used (burned in and ready to install in your new project)
The bunch goes as follow:

Sonicap gen1 33uF 200vdc- 6 caps- $250 plus shipping-Current price $97 from online store each.
Sonicap gen1 10uF 200vdc- 2 caps-SOLD
Sonicap gen1 15uF 200vdc- 2 caps- $60 plus shipping- Current price $58 from online store each
Sonicap gen1 1uF 200vdc- 2 caps- SOLD
Miflex KPCU 0.10uF 600vdc- 2 caps- $25 plus shipping-Current price $26.94 from online store each.
Jatzen Alumen 10uF 100vdc- 2 caps- $100 plus shipping- Current price $118 from online store each.

Save big and get these ones!

Got a piece of 3 mm acrylic to copy the AER Goldie. YouTube hybrid DML 4 Part easy simple build., Really! Instruments resonate on large surfaces way larger then most piston drivers. Less all the mechanical restrictions these panels are acting much like musical instruments. This technology is going to get real good fast. I think the simplicity and inexpensive design warrants more attention and interest. I'm hooked. This seems to be to good to be true but IS. Michael

Could we possibly create a refference topic on human hearing or audibility tresholds? I see endless discutions on better or worse thd sources, preamps, amps, dacs fighting their religious wars around -130db of THD +N when Dolby S circuits used on tapes established that below -81db we can't generally hear a damn thing in normal conditions.It might by just an opinion I share...but other than that what would be your scientific proofs of a different world than the one I think I'm living in?
We might probably hear some noise if we'd be living full time in an anechoic room, but with typical 30...60 db ambient noise i don't see anyone in need of more than -81db SNR or THD so why do we keep on proving how stupid everyone else's noise source is once it's past our hearing tresholds?
Why do we pretend to have heard, seen or made better products than others based only on lower numbers when most ears on Earth won't be able to hear it?
I only chose a random Dolby S movie on youtube, but you can google for others if you never heard a good deck with dolby s.I actually never heard a good deck with dolby s in terms of dynamics, but the lack of audible noise was a clear cut thing for me on Sony TC S1.I'm going to work soon on a Pioneer with dolby S...Maybe that will be a bit better in terms of dynamics .
I'm 45 years old and I can't hear any damn noise below 79db in a normal living room. THD and noise are the same thing below the audibility treshold. Can you hear anything lower than what dolby S can provide?!
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Hey all,

I've got a PHD5 Earthquake that suffered partial output failure. Amp is using HIP4080AIP and TLC271 in the output section. I replaced all output fets P50NE1 with IRF3710 (16). I also replaced the HIP4080 with a HIP4081 which I had available. The amp powers on and ONLY draws 0.25A and with green power LED, produced rail voltage of 80v. I briefly see ~10vDC on both speaker terminals then it goes down to 0v. Regulated voltage seems to be 5 to +13vDC on the opamps.


The HIP4081 is different than the HIP4080. When I put the original HIP4080AIP back in, the amp seems to work OK. Idles at 1A and passes audio.

HIP4080AIP includes a comparator that I guess this amp is needing to use.

I dont have any new HIP4080.

How can I be assured the original HIP4080 will work reliably, or should I wait and order new HIP080? These are very high rate failure components... but the original is some odd 20 years old and seems to be working. Apparently Newark is getting new stock of HIP4080AIP by 8/17/22 but then chatting with Newark online support they're saying 375 days. Farnell in the UK appears to have stock but I cant seem to have them shipped to the USA.

Hi!

I have a question about the application of the AES48 Standard when it comes to using two balanced inputs in the same enclosure. In this case the application is that of a re-amp box, thus ground isolation is important.

As per figure attached and the AES48 standard, generally Pin 1 of Input 1 is grounded to the enclosure. If Pin 1 of Input 2 were to be grounded as well, I believe that it might cause noise or interference should Inputs 1 and 2 be coming from totally different sources whose ground is not common.

However is this practice 'safe'? i.e. Is it ok for Pin 1 of Input 2 to not be grounded with the enclosure? As technically Input 2 would not be compliant with the AES48, right?

Thanks!

To be specific the early Iconic cabinets where the top, bottom and side
plywood edges are visible on the front

Needing the measurements of the Front Baffle cutout
for the Rear mounted Speaker.
The width of the side of the frame like appearance it forms
also possibly radius of the curved corners

Viewing the 1943 catalog The outer dimensions are easy to find.
39.5" High
25.5" Wide
17.75" Deep

Need the front frame measurements

I am basically using the model numbers from the 1943 catalog
Page 2 , Figure 1 and Page 3

Specified as Model 812, 812-PM, 814, 814-S
all basically using the same bass cabinet
with different options for field coil or
permanent magnet and higher gain amplifier
for phono/microphone

Which is why I titled the thread as So.
But if anybody has other useful Numbers, Model
Numbers or Search terms related to the Iconic
please suggest or provide links.

Only interested in this cabinet/baffle style



The General Purpose Model



Early Cabinets where bottom/sides
plywood edge is visible on the front.

Links, Discussion, Owners, useful search terms,
and Plans
Incredible welcome.

Far as Snobs and Negative Technical
Jibber, about why its old and no good.
I DO NOT CARE ! DO NOT POST

Positive discussion, fans and plans

Hi.

For an arts project I am working on I want to modify a cheap turntable to be able to play back records super slowly. From around 15RPM up to the standard 33,3 RPM.

I need the speed from 15-33 RPM to be adjustable with a dial.

I am not going for high quality playback, but more for the effect.

My thinking is adding a potentiometer inline between the regular speed selector switch and the actual motor.

Does this sound like a feasible solution?

Hope to hear back😀

I'm interested in exploring open baffle. Been reading a fair amount and wanted to gain experience so threw together something with materials I had around.

My system is 4-way active with digital xo and room correction, with sealed subs covering the bottom. They are ok to cross up to 80Hz, but I'd rather cross them lower, at 60Hz or less. I envision 8" mids and TPL-150 for tweeter (been reading StigErik's thread with TPL as dipole - and 21" woofers!!!).

I see most builds using 15" woofers, usually 2 of them (and no subs?). Most early work favored high Qts woofers, such as Eminence Alpha 15A. Martin King also liked the 15A, but he designed for passive crossovers. And later threads/posts seem to be ok with lower Qts woofers. So not sure what I'm looking for in a woofer.

Understanding if I need twin 15", or one, or 12", or 10" is kind of confusing so I assembled a quick OB with a couple Beyma 10G40 I have (Qts: 0.3, Xmax: 7mm, big motor). The MDF baffle is 32mm (2x16mm) and added the aluminum square tubes to gain baffle width, reaching 45cm. Placed it 90cm away from the wall, and took some measurements.

The room is pretty nasty: 5 x 4.85 x 2.4 meters, so basically square and height is almost half the length/width. This creates problems with bass response and I'm in the process of treating the room mostly with bass traps. Linkwitz recommends no treatment on the front wall...but mine is being processed, so I will have treated front wall and the speakers can be placed out up to one meter from the wall.

Pictures of the experimental setup 🙂

once I've tried to simulate simply closed box in these programs, and in each case the results was different
I put the same Vb for the same driver and the Qtc f3 and others was different. what is to belive to?

In your (the members') opinion, how critical is the quality of a Selector switch? I've been trying to source a selector for my pre-amp kit that was not included in the package. I've heard the sound of MARANTZ, PIONEER...etc and most restorations do not mention a replacement of the switch, but to just "Deoxit!" I bought a used MARANTZ and that was what I did to return the function of my switch and the balance knob. A generic switch will work, but the sound quality and durability compromised?
I'm sure there must be a quality standard applied at some point, but what would be a good switch brand name that would be reliably in that standard?

Francis

G'day Guys,

A question of theory or best practice or some such.

For something like a fairly generic OPamp based preamp, is a regulated PSU really that important?

For example:


Does a regulator eg: 7815/7915 or LM317/LM337 etc actually offer a noticeable performance benefit over just bulk caps or a CRC psu?

Isn't the PSRR of modern OPamps such that regulation is perhaps unnecessary?

I want to use three tweeters (same model), for example, three Scan D3004/6600, in a MMTTTMM design. Well, here're some imaginary patterns. Pick one.

There're too many possibilities I can't draw them all out. You could mount the tweeters unpside down, or switch 90 degree.




What, is this a very bad idea actually? Lay it on me, brutal truth.

From my personal point of view. The only advantage of class D amplifier over class AB amplifier is the efficiency of power supply. PWM can make the utilization rate of power supply exceed 85% when the output voltage is maximum. Therefore, class D amplifier can show its advantages when using voltage above + -50v. Preferably + -50v or + - 70V. That is to say, the total voltage is between 100-140v.
If the voltage is very low. For example, +12v VPP. Then digital amplifiers have no advantages. Because class AB amplifier is easier to design and manufacture at low power than Class D amplifier. Simple. Lower cost. The playback effect is also better. For example, lm1875 of + -25v and TDA2030A of + - 18V.
Or tda2005 with + 18V. In terms of sound quality alone. Class AB is better than class D.
It has no PWM conversion process. No EMI electromagnetic radiation. No output inductor is required. The inductor will change the output sound.
I think many people are making tpa3116. I think it is a relatively high distortion. The voltage is very low. An amplifier with low power. I didn't find it useful. I think tda2005 can achieve better results. Cheaper cost. It is also easier to make. I will spare a little time.
About 20 minutes. Design data. Then upload it here. I expect that a total of one CPU radiator is enough for stereo. No fan is required. It can meet the BTL voltage of output + -15v.
The standard circuit adopts bootstrap boost capacitor

I intend to build an amplifier based on 3e Audio's TPA3255 board. I'd like to include a volume control, but I don't need an input selector or tone controls, so hopefully I can just add a (passive) volume control.

In this article I read that there should be high ratio between source output impedance and amp input impedance, something like 100:1 or more. Given that the input impedance of the TPA3255 board in 10kΩ, the output impedance of my source (a Topping E30 DAC) shouldn't exceed 100Ω. Unfortunately, the output impedance of this DAC is unknown (Topping doesn't mention it in the specs).

Would it be recommended to just add a stereo potentiometer between the DAC and the TPA3255 board? If so, given that the output impedance of the DAC is unknown, what resistance would you recommend for this potentiometer? And I assume I need the logarithmic type?

I am looking for help identifying the value of capacitors C332 C333 C342 and C343.
The amp is a kicker KX400.1

Is there anyone that might be able to repair a 125ASX2 power amplifier?
I might have miss-connected the input or output and now it doesn’t work.

I want to wire 6 drivers together, four with an Re of 2.4 ohms, and two with an Re of 10.2, to share the power as evenly as possible.
I came up with the attached diagram, but have no idea how to work out the total load, or the relative power across each driver:

Hi everyone!

I am wondering if there are certain parameters that will make popular opamps like NE5532, LM4562, TL072, OPA2134, and others, to give the best performance as far as THD and sound quality?

When I studied datasheets for those opamps it seems that the lowest THD is achieved when R load is 2k.

Another parameter that I noticed was the voltage. For example, OPA2134 gives better THD performance when powered with dual 18V power supply.

One more parameter could be the gain. For example G=1, 2, ..., 100

The question that I have is, on individual basis, what would be best circuits that will allow those opamps to give the best sound they can produce?

Any comments are appreciated!

Thanks,
Pavlo

I find the "elastic search" problematic for a number of reasons (and I am certainly not alone).
Here are already two issues I find annoying:
-I didn't find a way to search for the threads started by a specific member in a specific forum
-The number of results of a search is limited, and bypassing the limit isn't easy or straightforward

Hey everyone

I have old Volvo 850 rear door speakers, which are blown, and i wanna rebuild them

I've found some cones made of 'carbon fiber' or polyurethane, can they be used instead of blown paper ones? Also - which glue you'll recomend to use?

But I have another issue - old tweeters - they have broken plastic, and i couldn't find anything looking close to them(Photo of tweeters bellow), or their type on market, but I've found some 'close variants' on aftermarket speakers, but i don't want to destroy other speakers to rebuild mine.

Any solutions ?

p.s. I'm newbie, or rather, 'noob' in this theme

p.p.s. Tweeter top size is around 47mm, bottom - around 15, height around 45, and bolt width around 3mm

Hi all...

If I had two of these:

KPT-305​

SINGLE 8-INCH TRACTRIX® HORN-LOADED MID-BASS DEVICE​

The KPT-305 is utilized as a mid-bass device in the 4-way fully horn-loaded KPT-MCM-4-Grand and the KPT-745. It augments the low frequency sections of these speaker systems for effortless, distortion free bass in large auditoriums

...and wanted to replace the 8" mid-bass drivers with say two of these (or similar):

B&C 8CXN51 8" Professional Neodymium Coaxial Speaker 100 x 100 8 Ohm​

...would this be something worth pursuing? Is this even worth trying to model with Hornresp (something I haven't learned to do yet) or would I be better off just building a true MEH (Synergy) horn?

Reason I ask is I have access to a pair of KPT-305-MB's and want to replace my Bohlender-Graebener (BG) Radia SA-320 in-wall's with something more dynamic and move to point source type presentation.

Thanks in advance!

Mark

I was able to get a Yamaha B-2x, I am planing for a full recap, my tech told me that he does not have the time to chase parts.
So I am going to find all the part and he is going to swap it.

I was able to find a pdf file with all the parts, however the list is from 2015.

Can you guys help find better caps for the project ?

The 4 100,000uf 6.3v are hard to find, the diameter of 2.0 inches, a seated height of 1.975 inches, and 3 lug design (1 dummy for additional mechanical attachment strength) with a lead spacing of 1 inch.

Since the amp runs hot, I was thinking using 125C caps

https://www.hifiengine.com/manual_library/yamaha/b-2x.shtml

thanks for your help

Selling the following:

1 pair of SA-9 Amorphous core Output transformers : 3.3K - 4/8/16 / 80ma and (optimised for 300B) : 650€/pair
1 pair of ITA-01 Amorphous core Interstage transformers, gapped at 35ma (used with a 46 in the driver stage of a 300B) : 400€/pair

950€ for all 4

All transformers are in excellent condition, selling due to upgrade to Nano-X versions.
Great set for DHT drive DHT SET monoblock amplifiers

Items are located in Belgium and will ship worldwide

Would anyone know what teperature of heatsink on Quad 303 running at idle should roughly be? I measure 45c at about an hour of idle. I thought maybe it's a bit too hot so tried bias settings but that didn't change anything.

I think that the resonant series method is the safest method of measuring an inductor because it does not depend on the voltage level applied by that I made this device with 7 capacitors selectable between 0.1-2.2 microfarad and with the possibility of injecting dc current into the inductor by means of a CCS with setable current 0-100mA ,what do you think, Thanks

Hi all

Just wondering if anyone would care to explain the pros and cons of having the CD diaphragm at the back vs at the front of the pole piece. I have seen both configurations on a range of CDs and wondered what the reasons are.

Thanks

Hi guys,

I am looking for a Fast/Soft rectifier for my F5...a "block" type package, with either screw mounts or tabs...something 35A plus.

I have heard great things about the IXYS bridges:

http://www.partsconnexion.com/PDF/l363.pdf

Problem is, they are PCB/solder pin mount. I really don't want to attach the big, solid-core secondaries from my transformer to those.

So what do you guys know? What is the preferred rectifier these days? Any recommendations?

You probably know what this is if you are here reading it 🙂

It is a killer amp/receiver using Tripath TA3020 chips! Amazing sound but I am moving and I have been trying to sell it on some sites (FB, OfferUp and Craigslists) but nobody knows how awesome this amp is. It is huge and heavy. So, cannot ship it (don't have original box anyway) but if you are in South Florida, you can pick it up.

The volume knob is missing but I bought a brand new remote control so didn't even bother to get a new knob. It works like it should.

Here is the thread to get more info: https://www.diyaudio.com/community/threads/motorola-dcp501.69293/

I am asking only $40!

PARC Audio full range drivers, from Japan, are on sale, 30-50% OFF.
They are famous and highly valued by wood cone.

DCU-F071W, 5cm Wood cone, 36USD, 2 in stock (new)
https://dream-creation.jp/image/unit/F071W/DCU-F071W.pdf
DCU-F101W2, 8cm Wood cone, 51USD, 4 in stock (new)
https://dream-creation.jp/image/unit/F101W2/DCU-F101W2.pdf
DCU-F101G, 8cm Glass Fiber cone, 45USD, 4 in stock (new)
http://dream-creation.jp/image/3rd_model/DCU-F101G.pdf
DCU-F121W, 10cm Wood cone, 58USD, 2 in stock (new)
http://www.ritlab.jp/shop/product/speaker/pdf/parc_audio/DCU-F121W.pdf
DCU-F121K, 10cm Kevlar cone, 64USD, 2 in stock (new)
http://www.ritlab.jp/shop/product/speaker/pdf/parc_audio/DCU-F121K.pdf
DCU-F131W, 13cm Wood cone, 85USD, 4 in stock (new)
DCU-F131W, 13cm Wood cone, 61USD, 2 in stock (slightly used for demonstration)
https://dream-creation.jp/image/unit/F131W/DCU-F131W-7.pdf
DCU-F131P, 13cm Pulp cone, 71USD, 2 in stock (new)
DCU-F131P, 13cm Pulp cone, 611USD, 2 in stock (slightly used for demonstration)
http://dream-creation.jp/image/2nd model/DCU-F131P.pdf
DCU-171PP, 17cm Polypropylene cone woofer, 100USD, 1 in stock (new)
http://dream-creation.jp/image/3rd_model/DCU-171PP.pdf
The prices may change depends on currency rate.
Shipping cost depsnds on the country too, around 30USD by surface.

Some videos:
Login to view embedded media Login to view embedded media Login to view embedded media Login to view embedded media Login to view embedded media https://youtu.be/h0Q4vvlMjR0

The aim is to unify the approach to testing new FET devices:

https://www.nist.gov/news-events/ne...gest-guidelines-assessing-emerging-transistor

I have a Spec-2 that was functional when parked in the turn of the millennium. I do have replacement primary filter caps for it from Newark. Unfortunately, I see that the old caps leaked (literally) and the PCB traces are corroded. I’m offering it for parts. It’s likely got good: transformer(s), temp compensation diodes (way obsolete), finals, drivers, sheet metal and knobs.
if you can actually use it, drop me a reply. I’m quite flexible on terms. I am capable of completely reviving it. I just don’t have the time to put into it. I’m not as young as I once was.

Hi,

I'm new here, please be gentle with me🙂

I have a Sony Playstation 1 - SCPH 1002 that has the AKM-AK4309AVM Chip/ DAC. I use the Playstation with my system to play my music collection.

Now, the Playstation is not reading discs. The disc is only spinning clockwise and anticlockwise. And I'm also hearing a click noise when the disc is spinning.

Before this happened, I did open the Playstation to look inside for some fun. And when I put it back together, the problem started.

I don't know what the hell I have done? I don't have the skills, patience and knowledge like the members on this site.

I'm aware there are members on here that use the Playstation as their main,second and backup CD player.

I don't want to lose this wonderful machine! Can someone on here repair this fault for me? I have no problem paying for the costs.

My Playstation is totally original. I don't want to have any mods done to it.

I'm in Southall, West London.

Thanks.

Shane.

For sale is a pair of icepower 200asc monoblocks using ghentaudio cases. Included is a pair of 3' XLR cables.

Hey guys and occasional girl,

As much as I adore this hobby and the gains that can be made from slapping big woofers on big baffles I do wonder about these new all singing and dancing soundbars?
I'm seeing some good reviews out there. It's inevitable that our hobby will change over time and much loved technologies/techniques will be superseded.
All that said.....anyone have opinions on decent sounbars vs decent "traditional" speakers?

A question for any truly advanced level mavens.
When we decide to fit a dataset with a line there are well defined algorithms like Least Squares fit in statistics.
All clear cut and reproducible.
When I want to, say, equalise a speaker then I have to best fit a curve with Poles and Zeros.
In parametric equaliser nomenclature that's centre frequencies and Qs, lo-pass and hi-pass, shelves and so on.
Similarly for a cross over, there may be a need to tailor the electrical response so the acoustic response behaves correctly.
Rather than just trial and error "there's a peak there so let's drop a parametric notch on that", has anyone seen any work on how to optimise the process?
The statistics literature has many ways to fit splines and the like but not quite suitable for this AFAIK.
It seems there should be some work on this but perhaps it's too nerdy for DIY?

David

made a start on the plinth for the sp10 yesterday,out with my veneer press to laminate the 25mm panzerholz to the 38mm chipboard, yes i know controversial and im sure the arm chair experts will be crapping their pants but if its good enough for the yamaha gt2000 then im sure it will be fine here.
west expoxy system was use to bond the panzer to the chipboard,normal adhesives are out due to the resin content of the panzerholz.




left in the press overnight and now i have this.



im undecided on the final thickness at the moment,i need to draw it to scale and see .

I can't believe I'm writing this, but I'm looking for a pair of Tango FG-50S transformers to build an Arch/SIT Nemesis amp. Alternatively, I'd be interested in a 64:4 Ohm transformer with similar specs.

I might have some v-fets for a partial trade if there's interest. For payment I can offer bank transfer or PayPal. Shipping would have to be to Austria, Europe.

Thanks for looking!

DD DM1500a, randomly blown power supply and output FETs, was told own hooked up subs wrong?

I removed all P.Supply and O.Put FETs, no switching on the tl494c or the lm393, I remove both to see what empty pads are getting/giving and it’s flat lines everywhere but 12.6v where it should be for each to function pins 8, 11, 12 on 494 and pin8 on 393 but 7.5v on pin 3 of 393), amp boots up blue light ok idling at .03a, I tried installing a known good lm393 to see if that does anything anywhere and it changes nothing. 494 gets no triangle wave/gives no waves, same as 393 regardless if good ICs installed for each or not.

Nothing else is probing bad with my DMM, except Q20, Q22 & Q28, Q30 are reading shorted between legs 1&3 with probes one way, same on each of the 4, but not when I reverse probes, so I’m assuming amp is designed as such and they are not actually shorted.

Currently reading up on the tl494 to see what it needs to operate, I know they have 2 comparators that need to run right to function (pins 1&2 + 15&16) and i am assuming the 393 is part of that and needa to function correcrly first before the 494 starts operating as it should.

Seems i have the hardest time with DDs for some reason, although the last i worked on had a bad PIC 😅 Any help greatly appreciated, i finally just got a new GPU and am in the process of rigging back up my watercooled gaming rig, almost ready for that guide, i have never wanted learning material this bad before ...lol

Hi,

most recently I stumbed across an article pulished by the German ELRAD electronics magazine in 1985. It describes the build of a 2 x 550W power amplifier, using Hitachi's 2SJ50 and 2SK135 latFETs.

As I still have plenty of these ancient power devices, I feel some itch to build this beast. Alas, the ECG40 dual transistor in the differential input stage is obsolete since a long time. Someone in GB offers them via eBay, but I don't trust this trade channel at all, at least not for obsolete semiconductors.

ECG40 has some sophisticated properties: V_ceo = 100V, f_T = 150 MHz, h_fe > 400 being the most prominent ones.

Are there any equivalent or replacement parts available? I guess the replacement doesn't need such high V_ceo, due to the cascode arrangement with two video transistors.

Another question: The author claims there aren't current balancing resistors necessary, due to the power devices' close tolerances. Is this claim trustworthy?

Still one more question: Note the swapped polarities between capacitors C5 vs. C6. What's the reason for this?

Best regards!

Good Morning All.

My wife has successfully established a wedding celebrancy business here in France, and (especially since the end of covid confinement) business is booming.

After 'messing' around with a couple of homebrew solutions, we have settled on a Behringer MPA200BT (https://www.thomann.de/intl/behringer_mpa200bt.htm) as a BT receiver and speaker. The mike that is supplied with the unit works fine for any readings that guests may make, but is not suitable for my wife.

She needs a wireless mike, handsfree (so either a lapel or discrete headset mike) that has good range and can tolerate 'line of sight' interruptions by the wedding couple etc. The transmitter also needs to be as small and discrete as possible.

A couple of other things that my be pertinent:

The majority of weddings are outside, so there may be wind, leaves rustling in the trees etc.
The biggest wedding we have done to date is 107 people, for which the Behringer worked fine.
A ceremony can typically last 30-50 minutes, so a rechargeable unit would be preferable.
I try and limit the distance between my wife and speaker to 10 metres, but occasionally we may have to go to 20 metres.
All 3 inputs may be live at the same time (BT, Behringer mike and new mike), so interference between them is a no-no!

We are currently using a 50€ Amazon device https://www.amazon.fr/gp/product/B07F3K6D6W/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1), which works fine and would be OK but it won't tolerate line of sight interrupions, where transmission is lost and silence descends...

I'd be grateful for any suggestions of devices, or further reading, for a better solution. Our budget is up to 400€

Zu Audio Omen Dirty Weekend II. Black satin finish. Delivered October 2021. No defects to finish that I can see. 1cm vinyl bumpers used instead of Zu’s expensive feet. They have a weak adhesive and are easily removable. Dimensions/specs: 36” tall with a 12” by 12” footprint, 54 pounds. 12-ohm load with efficiency claimed as 97 dB and a bandwidth of 35 Hz – 22k Hz.

Asking $1000. (Paypal fees and shipping additional)

ODW is no longer in production as of this year and their last stock was priced at $1499. Zu’s new entry level Union6 is $2899. This is a great opportunity to get one of the best values in audio.

Original box and packing foam available. UPS ground estimate $160-$200. Or better yet, spend a dirty weekend in Vegas and take a dirty weekend home.

Hi All...

I have built numerous of different topology of amplifiers and they do sound different, subjectively. To my ears that each has their own "character" to work best for each different genre. A great commercial loudspeakers pricetag are on the high side, endup I am looking into high performance loudspeakers, especially the very famous Purifi, SBacoustics, Bliestma recently. I am very new to those parameters especially on the time allignment, cabinets calculation, and carpenter works. I guess I might end up playing a lot of different speaker drivers and variants of cabinets during this journey, so I might as well join into the digital community and neglect on passive XO, and reduce the difficulty on carpenter works.

To step up the game, I am trying to make myself a DSP for this, but in a very practical, elegant, useful, and ultimate way. Attached with the device architecture that I am looking for. The multilevel Halfbridge topology MA12070 are actually very smart, (I am working on it myself for the PV industries and I am trying hard to make a 24V rails to output a 240Vrms without any boost circuits in the circuits.) To reduce the complexity, there will be no AD/DA chips during the processing paths, so guys there will be NO AKM or Sabre or your beloved R2R voodoo on this.


-2 x 4Ways DSP
-8 x 120Watts
-2 x ADC for calibration

-Streaming capability, Tidal or whatsoever.
-Audiophiles said they dont need a TV for their hobby, but i need it definitely. So it must has a 4k HDMI output, or even a 8K output with RK3588.
-8.8"inch LCD on the device for GUI.
-etc etc.

I have pick the chassis for this application too, its a 80(H)x320(D)x280(W)mm and it looks great.


Heres another idea: With digital XO, i can set a variants of XO preset for different genre of Music, but thats a very future stuff as I need to modify the playback apps for it to switched automatically.

Any comments or any guys who wish to join the development are most welcome!

How much bass boost do you consider ok to use with your fullrange speaker before you start to become concerned about distortions, intermodulation distortion probably being the most relevant?

I just aquired a pair of speakers. They are custom made by a skilled cabinet maker, based on the design of the original owner, the man who gave them to me, a former math teacher. He told me it is a bass horn designed in proportion based on the golden ratio. They have fostex full range drivers. The sound is wonderful and rivals the best speakers I've heard. I can get exact measurements later, the wood is 12 layer plywood. They are about 5 feet tall. Im wondering what you all think of this design, there are no folds inside just one flat piece of plywood going from the center to the bottom of the front baffle. Im not sure what exact driver is used. Thank you for your comments.

LinearX LMS in a Dell Dimension v333c (sorry, no monitor) software v3.72 on disk; M31 microphone, manual, breakout cable, mic cable etc. Also DOS and Win3.1 backup disks.


LEAP with dongle, both manuals, v4.60 on disk.


You can update to the last version of both at: https://www.physical-lab.com/


Also have two HP-500 printers for those who want to print natively from LMS/LEAP (add 75.00 ea.)


Buyer pays shipping from 14850 and please name you preferred shipper.


All will be packed well by someone who's used to shipping $35K Gibsons...


Thanks for looking! John

I came across this audio product site. It has unpriced (perhaps too expensive) audio hardware and software but may be worth a look.
https://www.nti-audio.com/en/products/software/speaker-test-software

Greetings everyone. I’ve been dabbling with audio upgrades and soldering for some time; however, I’m now doing a diy Dac project and need soldering advice. I use Cardas flux and solder (seems like there’s flux in the solder, also). While I always get great results, the flux remains on the board as a paste. I use a qtip and alcohol to clean off the flux, but, it’s tedious and time consuming. Is there a way to expedite the process?

Any and all advice appreciated!

Thanks,

John

Does anyone know the lower limit of R8? I have a QCC5125 BT board with an ES9023P that's powered from 3.3V. It has R8=100k with give 1.6Vrms output (no load).

I would really like to get the output level down to around 1Vrms without resorting to using a voltage divider. The datasheet says for 1.9Vrms, R8=220k. If I do linear interpolation of the known values, R8 would be a negative value for 1Vrms, so I'm guessing it won't work. That's assuming the change is linear though.

just picked up as early model of that. I designing a new sub-chassis for it. saw review of three commercially available sub-chassis that identified he center of gravity. Which is odd to the right a few inches. Which causes uneven pre-load on the springs.
Am i missing something in thinking that i should make one where the COG is under the spindle?

Looking for two W18NX001 Nextel. Used, in good as almost new shape and in Europe because of shipping cost.

If you‘re willing to sell me a pair please pm me!

Sometimes designer tries to solve a purely technical problem but at the same time creates a circuit that also has desirable subjective qualities. One such circuit is active gain control by the late Peter Baxandall. Basic idea was to create log action from the linear pot. Even the best log pots have audible discontinuities. Baxandall’s circuit solves this issue providing a silky smooth log action from the linear pot.

The circuit I used is from Texas Instruments tidu34, designed by Ian Williams. There was a TI demo (mono) pcb which used SMD parts. I used stereo TH pcb designed by the forum member Prasi (with a little help from Dragan100). Hat down to Prasi for excellent two sided board.

Original circuit is just attenuator but the circuit I used has 6dBs gain obtained by adjusting R8 in the original schematic. For testing purposes I used cheap TL074 DIP14 opamps because high performance quad opams in DIP14 package are hard to find. I had some problems with obviously fake TL074 bought from Ali Express and marked TI. Another pair of TL074 made by ST gave perfect results. Since TL07x are not very load tolerant I used higher value resisitors than ones in the original schematic. But even with resisitors several times the value marked in the original schematics subjective results were excellent. If DIP14 quad opamps like NJM 2060 or TLE2074 are used one can benefit even more from the lower noise that original resistor values provide.

What I like about this circuit is excellent control of volume combined with great sound. Unlike most log pots Baxandall’s circuit is pleasure to use. It is possible to adjust volume very precisely. Sound of the circuit is seductively smooth yet at the same time detailed and dynamic. It’s pity that Baxandall’s active gain control is not used more in industrial HiFi products. It is my impression that inverting stage of Baxandall’s circuit is responsible for the fine subjective qualities. First CD that I tried with tidu034 circuit was Tomasz Stanko’s „Soul of Things“ (ECM Records). I was surprised how palpable piano sounded and how detailed the sound was at low listening levels.

Hi,

One of my Abletec Anaview ALC110-2300 is totally unresponsive.

Nothing changed in my setup, and It wasn't shorted nor physically damaged. It just wont produce any sound nor give any voltage. This amp was working properly last time I used it.

I checked the spec sheet to see if there is fuse, and there isn't; only one for the secondary lines which it's not blown.

Any suggestions?

Hi everyone ! I have a Taramps MD 5000.1 amplifier that works fine on the test bench! The output off set is precise and does not give any problems! in the car, on the other hand, with the volume of the car radio set to 0, the amplifier moves the subwoofer back and forth, as if it were oscillating, then the oscillation disappears when the volume is given!

Cancelling this sale and relisting under another thread

Looking to send this to a new home, all together - pickup only in Austin, TX. Sorry, no shipping.

Included:
ACE-515 power conditioner
GFS-6 Speaker selector
GCD-575 CD player. The drawer opens then closes immediately. Otherwise fully functional.
GFP-555 preamplifier
GFA-535 amplifier. One channel dead. I purchased two of these dead, revived one and gifted it to a friend. A channel went out on this one biasing it up after the refresh. Had too many other projects to want to mess with it.
GFA-555 amplifier. Was functional when stored years ago, but my lightbulb tester says it has a problem now. Havent even tried to dig in, would rather send it on to a new home.

Also included: a transistor set from BD-Enterprises, originally purchased as spares from another DiyA member and potentially useful for either amp:
20-2SC2326K-AA
20-2SA1016K
4-2SA1207
2-2SA1210
4-2SA970BL

Everything above, except the 535, has been with/around my family since it was purchased new.

I have too many other amps to give these any more time.

$500 takes it all.

My humble 3 Amp system :

2 x Bookshelf : Woofer 6" 80W (50Hz to 5000Hz) + Tweeter 20W (1500Hz to 30K)

2 x Sub 8" 120W (25Hz to 1200Hz)

Linkwitz-Riley 3-Way 4th Order filter (24dB/Oct)

BASS: 20Hz~250Hz MID: 120Hz~4500Hz TREBLE: 2500Hz~30K

And that's my question : Is it Ok those overlapping frequencies ? (assuming I could equalize the high SPL at those frequencies)

Thanks.

I built a custom Jim Holtz Statements speakers a long time ago and decided to use them as monitors for home studio but I get bad sound only when playing my synth. I know the problem isn't with any other part in the chain other than the speakers or amp because I can play synth just fine from an headphone amp+headphones but on the other hand the speakers and power amp sound fine when playing through them recorded music. I'm sure I'm doing something wrong and suspects somehow artifacts are created because of the specifics way of the set up and location.

I tried measure loop gain of tpa6120 but i see weird problem. As you can see, Vin is 0db, that mean Vfb must be -6db (1/2 divider) but i got about -26db. I tried both Ltspice and tina spice, it's still the same, replace tpa6120 with some VFB opamp and i got correct -6db, is this a "feature" of CFA opamp?

Bear with me, its raining here and i‘m quite close to starting on this project so figured some planning might be in order. 😎

Been putting together pieces for a whole new entertainment system/wall for the new house now for a few yrs!

This will be a 2.2 setup, front wall is 13‘ wide, open floor plan back wall is 28’ , vaulted ceilings open to upper loft. here’s where i‘m at……. mains are 10” mtm (eminence delta 10b / b&c de250) stacked on top of eminence lab 15 in a 4 cuft sealed box (one each side)
i already have all these components so thats non negotiable, I got the boxes as flat packs because it was so much easier! (See pic)

idea was to stack the mains on the subs a little eq and time alignment , call it a day. (see pic for sub fr curve in 4’ sealed, light blue line……the other lines are for the mains (delta 10b) in different box tunings)

so seeing as theres a 60” wide x 30” deep x 24” tall ‘cabinet’ space just sitting there on each side wasted i thought about trying something like this (see crude drawing) just for the heck of it.…..goals with the experiment are to reduce distortion and make it easier to meet the 98db sensitivity of the mains. I realize it will limit the low end extension some but ill be using a 30hz high pass anyhow you look at it. I wanted to keep the folds to a minimum to keep flow and maybe reduce delay? And another question would be is the 4 cuft box too much to front load……i could smack together a smaller box or pack that one to reduce volume if need be, just trying to keep it simple.
Any help simming or modifying dimensions would be awesome……the external dimensions of cabinet or mouth exit location cannot be changed due to room limitation. (See pic of specs for lab 15, its a special order unit a little different than stock)

appreciate it, Bob

Fostex T500AmkII cd tweeters. These are top Fostex cd tweeter model. I have owned YL, GOTO, Raven ribbon and JBL cd tweeters and these are refined, sweet and musical like the YL/GOTO. Not lacking in body or tone.

Alnico magnets, 8 Ohm, 103db, freq response 4KHz-35KHz, recommended crossover more than 7KHZ. I ran at 8KHz up in JBL DD55000 clones very successfully.

https://www.lautsprechershop.de/pdf/fostex/fostex_t500a_mk2.pdf

Will be packed carefully and shipped. Buyer to pay shipping. Tweeters are in Australia and will be shipped from here. AUD$2500 (approx USD 1780)

Im looking for a matched or close matched pair of this tubes globe typ with nos or near nos mesurments.

Hello, hope someone might bring a sanity check on this.

Although I've successfully built and use 2 decent quality LDC mics, I haven't done any troubleshooting or repair on a Large Diaphragm condenser.

My friends sent me his Mic when it completely lost all output. First thing I did was open it up for a visual and basic continuity check. I disconnected one of the capsule wires and measured the DCR of the capsule. It measured a little under 2 ohms. My understanding is that a LDC capsule is a capacitor consisting of a backplate and a diaphragm, where the backplate gets charged with a 48vdc phantom voltage. So, its looking like a nearly dead short to me. I expected the capsule to measure like a capacitor, virtually open !

I just wanted to see if some of you might verify my expectations on my friends dead AT4040. Ha, the 2 ohm condenser capsule.

Thank you,

Best, Phil Donovan

Hi everyone.

I present to you today a small class A hifi stereo amp project based on :

• famous power transistors the sc5200.
• Elna cerafine audiophile output capacitors.
• Alpine audiophile knob

The sound of this amp is very clear with a lot of current, I tested it with jbl 4430 speakers, the result is very impressive!!

Attached is the complete manufacturing video on my youtube channel where you will find other audio projects.

Login to view embedded media

Hi, Im looking on a pair of Fostex tweeters used to buy for a fair price. Plese contact me if you have some for offer.

NAJDA IS NOW SOLD-THANK YOU

WAf Audio Najda dsp, preamp, dac. Built at factory 2017. I am second owner. Used sparingly since then. Not used at all by me. In excellent condition. A great versatile dsp for multiway speakers. Original owner set it up and ran it in a mutliway horn system and had great sucess in the time he owned it. Comes with factory box/packaging, factory verification certificate. Excellent condition. Is in Australia. Sorry but I cant answer too many technical questions on operation but know there is much info on net. AUD$600

Hello ! Does anyone have a schematic for Avaline ILX 1202 power amplifier ?

Or equivalent ...

Thks

Hi,
What are the pros and cons to use a Bessel 12 dB slope crossover over a 12 dB Linkwitz- Riley, please ?

Does the Bessel need a physical offset when made passive like the LR ?

Does the Bessel exhibit better group delay if used for a bass to woofer driver cut off ?

What about the off axis when used for a tweeter ?
Can we use one for the low pass and the other for high pass without problems ?

Thanks

I was curious how the WE 91E single ended power amp can deliver 20 watts with single 300B. Finally I found their US patented paper which is very interesting to read.

I'm just putting the finishing touches on my first Class-D DIY amplifier. It's nothing fancy, just an ESP32-WROVER board (to be running Squeezelite-esp32) connected to a PCM5102 board for DAC via I2S with this wired to a rather inexpensive TDA8932 BTL Mono Amplifier Board while I'll be using to power a single bookshelf speaker. The amp is advertised as working best at around 24V. I've been digging through my box of discarded AC adapters hoping to find a match and the best I can find is an old Lenovo Laptop AC Adapter which runs at 20V and can provide up to 90W (which on my math is around 4.5A). My understanding of electricity is that amperage provided will be a matter of what the device pulls in, so I can use an overpowered amp without fear as the board will draw however much it wants in a given moment and that 4.5A is just the ceiling for what it can provide.

To sharpen this information towards a couple questions:

(1) Am I right in thinking this will work as a PSU for that little amp? Happy to hear tales of success or woe on other similar builds using Laptop AC PSU
(2) I'm considering splitting the PSU into 2 power channels with 5V for the ESP32 and the rest for AMP. Anyone want to advise against this? I can just use a separate USB power adapter, but seems a bit silly to use two cords.

I went a different route with my sub amp since the amp I was working on has nothing but issues . One day I will repair it but in the mean time I’m using different amps .

My amps consist of 2x Digital designs M5A’s for the subwoofers.
A digital designs D4.100 for the mids
And a D4.75 for the tweeters .

My head unit is an Alpine ILXA-W650.
The head unit has an eq I believe crossovers and other adjustments like time correction .

My question is adding this piece a Benefit for the system or just a waste of money and I should just use the headunit and set everything up through it .

https://ddaudio.com/active-pre-amp/dsi-3/

Speaker Crossover Calculators

I found this awesome calculator. Want to do a hi-pass x-over for SEAS Prestige 27TFFNC/G tweeter at 4-5kHz combined with 6dB attenuation (based on measurements using variable LCR pot I got from Parts-Express).

My questions are:
1) Can I just put the capacitor in series in front of the 2 resistor attenuation circuit?
2) I thought proper attenuation required LCR, not just 2 resistors. Is there any disadvantage to just using the 2 resistors shown in this calculator?


I chose the SEAS Prestige 27TFFNC/G tweeter because the small size allows me to put it very close to the mid-woofer. I figure with an x-over this high, it is more important to get better dispersion than any improvement in sound quality.

https://www.madisoundspeakerstore.c...stige-27tffnc/g-h1396-1-textile-dome-tweeter/


Strange thing is the identical tweeter but in rectangular shape gives a smoother output

https://www.madisoundspeakerstore.c...7tffnc/cg-h1406-1-textile-dome-tweeter-4-ohm/

Hi everyone,

Just before I start, I'm a complete noob at this. I apologize in advance if I get things wrong.

I currently have a really tall tapped horn (not sure which type exactly though) that was given to me and I really like it. I recently got an old subwoofer from my dad, so I want to build a mini tapped horn that preferably is light and small to carry around, while still being loud and getting to the low frequencies.

The old subwoofer/driver I have is a Fusion EN-SW12ES. Note there is like no documentation/specs online except here, however I'm not sure if that's accurate.

Now I have no idea if this subwoofer would be well suited in a tapped horn, but from what I understand, tapped horns are good because they get really loud. I plan to use this subwoofer for small DJ gigs (like college house parties, DJing with friends, etc.) so I want it to be loud while still being compact enough to carry around, compact and light enough that I can lift it by myself. I usually play lots of bass-heavy music, such as trap and EDM.

I've been looking at some tapped horn plans; mainly the two I was looking at was the THAM12 and CUBO12. Additionally I was looking at a MTH-30 but I think that may be too big. From what I understand, the THAM12 may be better specs-wise, but the CUBO12 is smaller, easier to build, but does really bad under 40hz.

Due to the lack of documentation on my driver, I can't really simulate different enclosures in Hornresp well (or accurately, I doubt the linked spec sheet is accurate to be honest). I also can't simulate the CUBO12, so its hard to compare the two tapped horn enclosures I was looking at.

Right now, I think the THAM12 might be the best option for me (however my decision changes literally every day 😅)

What is the best tapped horn enclosure that is small enough and can get to low (enough) frequencies? I know there isn't a good compromise, but I've been stuck researching and comparing the THAM12 and CUBO12. Or even would this be better in a non-tapped-horn enclosure?

I needed to house a general-purpose lab filter and its supply in a case.
The case had to be metallic, and steel, to minimize the influence of external magnetic and electrostatic perturbations.
The device had to be class II, to avoid ground loop issues, and it had to have a minimal primary/ secondary capacitance, because the tens of µA it creates can induce pV or nV drops along the shields of unbalanced devices.
In short, it had to be as quiet as possible.
A 50 Hz transformer inside was out of the question, because of the huge shield it would have required.
This left me with two possible solutions:
-A traditional wall-wart, connected with an umbilical
-An ultra low noise mains supply, small enough to fit inside the case

I didn't want the inconvenience of a wall-wart: I wanted something completely self-contained.

For the supply, I used this concept:
https://www.diyaudio.com/community/threads/symetrical-colpitts-oscillators.329968/post-5601529
The frequency of operation is ~100kHz, sinusoidal, and the I/O capacitance is <10pF, of which most is "dead" capacitance, from GND to GND.
This means that no dreaded "Y" capacitor is required, unlike a regular switcher.
The power required is +/-18V @ 30mA, + the LED, which the supply can easily provide

The case had just enough room to accomodate all the circuits, + the shielding and the class II insulation, but it would have meant an awkward ergonomy for the front panel, making the instrument unpleasant to use.

The solution I finally opted for was to attach the supply outside of the case, but it needed to be protected, mechanically and electrically.
I found this ad-hoc cover, fulfilling all the requirements:



Do you guess what it is?

Yes, a sardine can. It was the right size, and had all the desirable properties.
I over-painted it, maybe should I have left it natural?

anyone knows which DA chips are in ?

all I can find ( no pics inside!) is "18 bit 8* oversampling DACs"

TIA

Hi

Recently I bought a Micromega Solo CD player to use as a transport.

Just thinking if it’s good to diy some simple conversion to a pure transport.

My thoughts include both internal processing and external aesthetics…

1) take out all unnecessary analogue part of the circuit
2) change all wires to pure silver wires
3) change the power and output transformers to higher quality ones
4) install a hdmi i2s output
5) replace the acrylic cover with a gorilla glass one
6) diy a lighter clamp

Welcome any comments and advice.

Many thanks


Best regards

I have a total of 12 left, after a overseas buyer purchased around 18-20.
Would like to get $20.00 each plus whatever shipping USPS to your location would be. Probably not more than around $6.00

.