Just as everyone else, I am running down on my reserve of 2SK389/2SJ109s, and am looking for the best possible substitute.

The LSK389 is only available in N-JFET, and is not pin compatible. So for me no solution.

The most obvious solution is to use still available 2SK170/2SJ74 matched pairs. If you have a large pool, you can get them even better matched than the 2SK389/2SJ74 (spec at 3% match).

http://www.diyaudio.com/forums/showthread.php?postid=1689279#post1689279

But how about thermal coupling ?

You can glue them on the flat surfaces with silver epoxy, but you mess up the pin compatiblity to the duals.

So this is my solution. 😉

It has a factor of 3 more thermal contact surfaces than just gluing on the flat surface, for much improved thermal coupling, and is still small enough to fit in most applications, with a footprint of 16x8mm.

The heatsink helps to increase thermal insertia and hence thermal stability, and keep the temperature a bit lower than without.

They are not extrusions (with a minimum order of 1 ton in weight), but rather CNC wire-cut from solid. This also explains the rough surface finish, which is an added advantage as it increase surface area for heat exchange.


Merry Christmas,
Patrick

USB WiFi dongles confirmed working


COMFAST CF - WU735P
D-Link DWA-125 Wireless N 150 USB Adapter
D-Link DWA-182 Wireless AC 1200 Dual Band Wifi USB Adapter
Edimax AC600 Wi-Fi Dual-Band Directional High Gain USB Adapter
TP-Link TL-WN722N 150Mbps High Gain Wireless USB Adapter
TP-LINK TL-WDN3200 N600 Wireless Dual-Band USB Adapter
TP-Link TL-WN725N 150Mbps Wireless N Nano USB Adapter






Direct Ethernet(PC to PC, PC to Laptop, Laptop to PC or Laptop to Laptop) settings if you can't connect via WiFi a big thanks to Indiglo for these



Daphile Settings

IP address: 10.0.0.60
Subnet mask: 255.255.255.0
Router: leave blank or 0.0.0.0
DNS servers: 1.1.1.1
Search domains: 0.0.0.0

PC Settings
IP address: 10.0.0.61
Subnet mask: 255.255.255.0
Default gateway: leave blank
DNS servers
Prefered DNS server 1.1.1.1
Alternate DNS server: 1.0.0.1





if you know of any more please leave a comment with the name and i will update the list

Does anyome have access to actual in cab measurements taken from a Vifa M22WR09-06 driver?

I'm trying to sim a crossover and can't find anything other than the ancient Vifa factory measurements which dont help me with the in-baffle/box response.

Thanks

Here's a try using a Klipsch Heresy I with K22 spec woofer.

I may have not damped the port enough.

The Z peak, normally in the 65Hz region is flattened. Some peaking in the response curve shows (as does significant port output)

Hello,
Maybe some people on here will be able to answer this:
I'm looking to construct a Simple Speaker Protection Circuit using 2 x Back to Back Electrolytic Capacitors. To get reasonable Low frequency Response using a 12" 8 Ohm Driver, - (looking at commercial designs) - I assume that I will be needing a Capacitance Value of at least 2-3000 Microfarads to go in series with the Speaker Output. My Power Amplifiers run 60 volt Plus and Minus Rails, so I was thinking that 2 x 6800uF Capacitors connected Back to Back with a Voltage Rating of 40 Volts would be adequate. Somewhere else suggested using a Diode connected across each capacitor, with the + of the diode connected to the + of each capacitor would work better, to do with keeping each capacitor formed. At the moment, You cannot get Bi-Polar Caps with more than 2,200 uF at 25 Volts.
Here, I'm trying to get away from the idea of Isolation Relays or Series Forward Biassed Power Fets, because all of this can still fail. I'm looking to transfer no more than 50Watts of RMS Power, the rating of the drivers.
I'm sure that with everyone's vast experience on here, someone will know the answer! Thanks, and Kindest Regards - Telnet100

Building speaker cabinets I can do.
Building a crossover? Uhhh....

I'm building a pro audio cabinet. But the final design was just too big. I had to downsize for portability and the trick was that I would need a high pass filter for this box.

BassBox Pro Tech Support is telling me I need this:
What you need is an active 2nd-order high-pass EQ filter with Q = 2. This should provide a +6 dB bump at the filter frequency and a 12 dB/octave roll-off below the filter frequency.

Can someone help?
Maybe sample schematics or plans I could modify for my needs.

I'm open to any guidance.

I have around 100 120v:11.5v 80VA power transformers that I am trying to find a use for. They are basically factory seconds with various connector issues, etc. I also have a more or less unlimited supply of 26awg magnet wire from shaded pole fan motors of the same situation. I am thinking about cutting the "El" cores of the transformers open, 3d-printing bobbins and making "EE" core filter reactor chokes with an air gap between the "E" sections to prevent saturation because of the DC. Maybe lay a piece of fish paper between them for better insulation/separation. 26 awg isn't very thick, but I could wind several conductors in parallel for better current capacity. Does this idea have any merit at all? Is there a better way of going about it? All of this stuff is going straight into the trash if I don't snatch it up first, and I hate seeing it go to waste.


Edit: I also have a cache of microwave oven transformers as well, which I have done several things with. I've considered the same "EE core with air gap" format using them instead. They'd be huge, but I imagine the inductance would be huge as well. I'd of course cut the original windings out.

I just saw this article and I thought you guys might like it. It looks like a company created a special type of screw to help turn drywall into sound absorbing panels. I'm really curious how they perform. Considering the price of building a room with great acoustics this would be an amazing way to improve a room, as well as a whole house, for peanuts.

New Spring-Loaded Screw Turns Drywall Into Sound-Absorbing Panels.

The remote control seems weak.
Its not the batteries, they are new and have correct voltage.
Its for a quad77 cd player and the remote only works when close, say a foot or 300mm. What goes wrong?
Thanks
thyristor44

If someone from European Union has a pcb with Twisted Pear 9028Pro (preferably without Tridents) which he doesn't currently use, please pm me.

I am building a Troels larger box design and he uses quite a bit of internal bracing with nice round routed holes etc. With the current price of lumber in the US I found that steel bracing would be much cheaper on a cost per stiffness basis. Plus I prefer welding and cutting to routing.


So I am thinking of a rigid space frame internal construction and with front mdf baffle and sides attached to the frame. Still keeping the designed internal volumes.


Any big drawbacks to this plan?

This is a tough one, but a very serious inquiry and I am sort of desperate for a solution. I'm wondering if there's any way to lower the output impedance of my SP200 headphone amp, to better match the ridiculous 9 ohm impedance of my beloved Shure SE846 IEM's.
----------------------------------

Some background:

I recently upgraded all the phone amps in my recording studio. after extensive trials with every highly-regarded amp under $600, I settled on the SMSL SP200.
(Not the Massdrop, which I didn't test) It's amazing for the money, and after a psu cap upgrade, which tightens the loose LF, it's staggeringly good.

Unfortunately, I stupidly only tested the amps with studio cans, from 250-600 ohms. I forgot that low impedance IEMs might give different results. My Shure SR846 are about as low as it gets, at only 9 ohms. The SP200 was independently tested as having about a 1.3 ohm output, and yes the mis-match is extremely audible. Harsh, distorted, and a massive loss of LF.

So that's where I'm at. I REALLY don't want to start looking for alternative IEM's, although that may be the only solution.
=============================================

AND SO:

To be clear, I need lower impedance, not (just) lower gain.

I tried an inline resistor network at 80 ohms, but while this brought back the LF and lowered the distortion, it also killed a significant amount of HF. (resistance is not capacitance.) Ugh .....

Maybe a different resistor network design would work better? I know there are L pads, H pads, etc. They all drop the volume, but maybe result in different amounts of HF loss? But probably not, so on to possible amp-mod solutions:
-------------------

I don't have a schematic, so all of this will be tricky even for you guys. For me, it's like a chimp doing quantum physics equations. Well, regardless:


Idea #1: Maybe change the amp's gain structure, by lowering both the input and the output resistance?


Idea #2: Maybe add a little "buffering" circuit on the output. Unity (or even - 6dB) gain but with a super-low output impedance?


Idea #3: Maybe use a different op amp?
The two stock SP200 gain op amps are OPA1612A.

The Benchmarl HPA4, a $3,000 THX-888 design, uses 2 OPA 564 op amps. Surprisingly, (to me) It also uses a pair of OPA1612A dual op-amps as "error-correction" amplifiers.

The HP4A has a rated output impedance of “less than 1 ohm” .
Given my SE846’s 9 ohm impedance, that could actually make a big difference to me.

I’d LOVE to know why Benchmark used this alternate 20-pin power ic, and then used what the SP200 uses as some kind of ancillary circuit. What is “error-correction?”

And the obvious questions:

# Can the OPA 564 be used as a direct-replacement for the SP200’s 1612A? (I suspect not)

# If so, could it possibly have a lower output impedance?
- I’m guessing that this is indeed why Benchmark uses the 564, but then something in that IC requires the “error correction” 1612A’s to be added. In which case, there is of course little hope of a direct-swap.

The B1 thread is already bigger than 1500 posts. In this big pile of information I'm not able to find which JFET's can be used instead of the standard 2SK170/LSK170/2SK370 types.
Purpose of this thread is to make a list with suitable replacement JFET's for use in the B1 buffer. Any information on the performance of the replacement devices compared with the standard ones is welcome.
Some possible alternatives:
J309
J310
2sk117
2N5459

Preferably pro audio. Pair.

🙂

I get this board, you see "48V" on power input

you see on board LM2575T-12 (Input 45Vmax)
my board has LM2576S-12 (Input 42Vmax)

so, of course both can't be used with 48V,
because there is a direct connection form power input to the regulator.

so, I'm looking for a discussion on diyaudio with but unfortunately
all threads are longer than I can read

What can I do?
change the regaulator to LM2575/76 HV

I like to do anything to change the board to get the values from datasheet

Trying to simulate a bass tone controll.
Seems I get the same frequency responce at all potentiometer states.

What could be wrong...

I've noticed a quite few people seem to be having all sorts of problems using WinISD when trying to design speaker cabs. So i thought i'd explain how i do it.

Enter the Thiele Small parameters from the drivers data sheet in the order you see in my screenie.





A = Qes

B = Qms

C = Fs

D = Re

E = Vas

F = Pe

G = Xmax

H = BL

Pay VERY close attention to the terminology, as there are multiple choices available to choose from in WinISD. This is because not all manufactures list them identically. One incorrect entry and your design will we way off, and will NOT work as you hoped.

For example - Vas might be listed as 9.288 cubic feet, which is the same as 263.00 Liters in my screenie. If you carefully click on the appropriate position, in this case L as shown by the red arrow, you are able to change it to match what your data sheet shows.





Also notice how the text in the white entry boxes are coloured. Green, Blue and Black.

Green = Manually entered data

Blue = Automatically calculated

Black = No data

If you Carefully follow the above advice, then you should be now be able to design boxes more confidently and accurately. I've been using WinISD for many years this way, with great success both commercially and privately.

Happy building and listening,

Regards

Zero D

I have a halfler dh 220 that has the high end Fantasia upgrade with the turn on thump kit installed also . I have noticed a humm/vibration that happens about ever 45 seconds and last for about 5 seconds . You can feel it also if you put your hand on the amp while it’s doing it . Any thoughts this doesn’t seem normal to me ?

I have a updated Hafler Dh 110 that when I touch the Bass tone knob I get a hum through the speaker and also the knob wiggles when moves up and down and side to side . All other knob are tight . ? Any thoughts

It seems difficult and/or quite expensive to find a symmetric DC power supply capable of adjustable rails of up about 70 Volts DC capable of delivering about 5-6 amps.

In my possession, I already have a:

- 1000 VA toroidal transformer (120/240 VAC -> 2 x 50VAC).
- dual gang 40 VAC -> 40 VAC 10 amp variac (Powerstat 116CU-40-2)
- 160 amp rectifier
- about 200,000uF @ 200 volt electrolytics.

So I decided to do the following, please indicate if you see any flaw with it.
The idea is to feed the 50 volts from each secondary of the transformer to the 40 V inputs of the dual gang variac. The outputs are rectified and filtered and I get a very powerful (with very little ripple) power supply of up to about +/- 70 volts DC at about 10 amps max.

One issue I am thinking is that specific variac is specced to run at 60Hz. If I move this to a 50Hz country, I presume the max current rating will probably be less but does anyone see any other issue ?

I am adding a picture here:

Some years old but in top working condition build with top parts and the sound is verry good from this little chip amp. Plese se on pictures for more detail. Transformers are from Talema with 18V secondarys. The psu is build with Panasonic Fc 7 pieces 3300uf 35V per rail. There are four rails so all together 4 x 23100uf.The lm 3886 pcb are from Brian GT build with good parts like Amtrans and Takman resistors, Elna Silmic and Panasonic Fc and Nichicon capacitor. The speaker conector are missing but I ordered new one, so the buyer will become complet build, plug and play amp. The enclosure you must build by yourself. Sorry no time for this. Price is 250eu plus shipping inside EU
Or best offer.

For sale: transport USBridge Signature from Allo - sold

I bought this USBrigde Sig in March 2021. It has been used for less than 50 hours or so roughly. I only added a heatsink on the raspberry Pi CPU. The rest is original and working condition. It also includes an USB dongle (also bought from Allo) for wifi with very good range and speed. I also include the SDCard with Volumio pré-installed and including latest driver for the dual band wifi dongle.

Price on Allo.com: 239$ main board and 24$ USB wifi dongle (USD).

I would sell for 190$ USD for both or 170$ for main board w/o wifi dongle

Note: It does not include the power supply.

Shipping price needs to be added of course. Please specify preferred transport.

Fab

Hifonics VI Colossus amp half in protect

Started working on an old Zed Hifonics VI Colossus, which is essentially 2x Mono block amps I believe inside. Separate everything.

One of the amps powers up fine. Not sure if it will play though as I'm servicing the other amp which has the RCAs on it.

The bad amp, with RCAs, powers up for about 5 seconds or so and then falls into protect. My DVM is sensing +2~3vDC on speaker terminal which rises up to about +3vDC before the amp kicks into protect. Positive and negative rail voltage seems to be alright during that time. I found numerous bad solder joints which I cleaned up. Rail caps are testing good off the PCB.

There are no opamps on this board, only discrete components. Regulated voltage appears to be OK.

I've not seen very many VI amps.

Does anyone know what components I can remove to keep the amp powered up for testing, or any other thoughts as to why there would be +DC on speaker terminals?

Photos in a moment.
Thank you

Hi has any one listen to the DNA Sequence speaker or build a similar line array?

On paper its sound good, and I like the idea about line arrays, but until now it's has always been 2 or 3 ways systems for me.

So why did I start this thread? I just want to gather as much information about the DNA line array as I can.

Please tip in😉

Beginner's Chip Amplifier, HiFi LM1875, The Amplifier Board

This is for the purpose of an accessible hifi chip amplifier, it is in reference to Commercial complete Gainclone kit for a beginner? - diyAudio and it is by request. Here's LM1875, at low cost, and easily made by following the "play by play" photographic format (starting at post#24). The LM1875's "only 5 pins hookup," and the absence of spike system noise, can give you 25 watts per channel of high fidelity, at a bargain price, and with an easy time of building your own amplifier.

But, first, let's have a look at how "not" to use the LM1875: If you're planning the maneuver of pushing inefficient speakers with great force, then try something else. Our introductory LM1875 project here, has not been paralleled to withstand 4 ohm speakers.

LM1875 works great with efficient 8 ohm or 16 ohm speakers: Since this thread starts from Gychang's post and since he is famous for the full range hifi genre speakers, then I think that the laid-back hifi sounds of LM1875 could be a perfect fit. Any reasonably efficient 8 ohm speaker is suitable.

Circa 2012 update
Suitable transformer voltage is actually 18+18vac or less. These transformers are affordable: Antek - AN-0518 Monobloc/dualmono build is recommended for current control and wider imaging. For good longevity don't give an LM1875 chip access to more than 1a~1.5a worth of transformer. That's why Monoblocs really make sense.
Input load resistor should actually be 10k (not 15k).
Due to lack of NFB-shunt cap, consider adding high quality output cap assembly, in series to the speaker, for long lasting speaker protection. Adjust capacitance value to suit speaker size for enhanced headroom. Output caps strongly recommended if using irreplaceable speakers with Any chip amplifier kit or project. (click this link to see older nearfield design). The 2012 edition is a slightly refined version of the circa 2008 original, and suited to studio mixer/desktop use.

Circa 2013 update
With its gain of 34X, a computer sound card or digiplayer can drive this amplifier easily, without straining the source device. Now for 2013, it does have the NFB-shunt cap so it can't amplify DC. The parts paralleling shown is for high end quality at low cost. Output caps are no longer shown on the schematic but they are fun to use for bass and headroom enhancement. Tone option: To compensate for a peakish speaker, add just ONE of this model 4.7u from V+ to V- (rail2rail cap) at the amplifier board's power circuit to cause quieter midrange with higher resolution. Mains fuse and speaker jack fuse are suggested. Each monobloc produces up to 25 watts of power to an 8 ohm speaker.

Power Supply
Here are CRC power supplies for these monoblocs:

Option: You can use 3300uF 35v or 50v caps, such as Nichicon FW or Panasonic FC.

Transformer Voltage
Example transformer voltage is 18+18vac
Click on best match for your application to see a hookup diagram.
♦ Your mains is 120vac and your transformer is 18+18 or less?
♦ Your mains is 230vac and your transformer is 18+18 or less?
♦ Your mains is 120vac and your transformer is 36+36 or less?(dual primaries in series)
♦ Your mains is 230vac and your transformer is 9+9 or less?(dual primaries in parallel)
(please assure that the transformer output is 18+18vac or less)
And see Decibel Dungeon for a briefing on how to power your audio amplifier, including construction and safety.

Transformer Amperage
Greater durability can be had via good design and a right-sized transformer, or you could use a lot of fuses.
Monobloc/Dualmono:
♦ 36va*0.67=24 watts, which is perfect; however, we might want to adapt to dual secondaries and twin bridge rectifiers to maximize the little 1 ampere transformer. Use a mains fuse.
♦ 50va*0.67=33 watts, which is a bit too much; however, that's safe if given a Center Tap transformer (just one bridge rectifier) And the CRC power supply. Use a mains fuse and speaker jack fuse.
Stereo:
♦ 100va, instead of breaking chips, you may choose to use mains fuse and rails fuses for right channel amplifier board and rails fuses for left channel amplifier board and speaker jack fuses for each speaker. No matter if stereo or monobloc, a minimum of 7 fuses is mandatory if the transformer is greater than 50va.

Before powering on the new amp
Here's AndrewT's checklist:

AndrewT said:

Have you powered up via a bulb tester?
Keep this bulb tester in circuit until AFTER you have completed all tests and proved you have everything wired up correctly.
Have you powered the transformer alone and checked you have it wired correctly?
Have you powered up the transformer and rectifier and checked you have it wired correctly?
Have you powered up the transformer, rectifier and smoothing capacitors and checked you have it wired correctly?
Have you powered up the transformer, rectifier, smoothing capacitors and one channel of amplifier and checked you have it wired correctly?
Have you shorted the amplifier input and checked you have near zero output offset?
Have you measured the output noise with the input short in place?
Have you removed the input short and re-checked the output offset and output noise?
Have you connected your source and re-checked the output offset and output noise?
Have you tried moving the volume control and switching the source off and on and checked the output offset during all these changes?
Now you are ready to connect a dummy load.

Click to expand...

I would also like to suggest putting a capacitor in series with the speaker for protector. It costs less than replacement speakers. And you get the Bonus of fun bass efficiency tuning for maximized headroom (a lot more power), by simply reducing the capacitance size to match what the speaker can do and roll-off what it can't do. This makes your amplifier output only what the speaker can use. Cheaper: If installed at speaker ground of a stereo build, two speakers can share the protector.

Avoiding destruction
It may be very difficult to get up and running without the NFB-Shunt Cap, so here's a photo of the old 2008 project re-fitted for greater durability and so it won't amplify DC. This added part, NFB-Shunt Cap is the electrolytic cap in the upper-left corner pictured. Whatever else it may do, it is absolutely certain to give you better odds at building a working amplifier. So, use it.

I am planning to build a music system. I was searching around some amplifier boards, and I found these two PAM8610 2x15w and TPA3110 2x15w which are good but which is better? Also I am using 12.6V BMS 3S 20A 18650 Lithium Battery Protection Board to power the board.(also I heard that Pam8610 has some noise distortion and something)

hi I need help, I have a nad av 713 5.1 surround digital amp and it is making static and pop noises in both channels and in both speaker sets (A&B) I have tried cleaning the potentiometers and it hadn't helped 😡 also i have tried all the inputs and they have the same problem if anyone have any ideas of the culprit i will be more then happy tor hear

thakns

I am coating the interior of a speaker enclosure with these bitumen damping pads:

Solen Electronique Inc. | DAMPING PAD

The pad have a thick easy to remove plastic film under the self adhesive side, but on the other side, there is a very thin plastic film that is very hard to remove.

If I try to peel it, only small sections can be peeled peel off at a time, as the film has no elasticity.

Is it meant to be removed ?

I would prefer to leave it, because the pads have an unpleasant bitumen smell, and it would save the trouble.

On the other hand, felt needs to be glued to the pads, and perhaps the film is not a great surface.

Suggestions would be appreciated.

Hi guys I have 143x LME49990 to sell from an old stock I recently found.

101x Are new and unused, bought from Digikey in Jan 2016. 10€/pc
34x New and unused. Buy date unknown but must be before 2016.

8x Are used. 1€/pcs will only be shipped when buying new parts. Max 2/person depending on demand.

PM if interested.

Hi,
I've got a pair of beautifully made pyramid shaped speaker cabinets. Mixed wood finials with ebony.


They're 75cm tall, with a 30cm square base. The internal volume is 21L.


The cut outs for the 3 drivers are; 1", 4" & 7 1/2".


Sell the cabinets on, or invest in getting them working?


Cheers for any advice.

I am concerned about impedance matching of a microphone circuit. This is an electret mic.

Perusing standard XLR type audio cables, I don't see any impedances mentioned. This would be handy. Anyone know what this number might be?

I would assume the output of the mic and its associated circuit would match this at typical audio frequencies.

Thanks
Fritz

Hello!

I have a speaker restoration project with missing parts on the crossover, i got the component values and types from a helpful member on another forum.

I made some drawings from the crossover (not a professional). Can somebody explain how this crossover is working (mainly the woofer section) and what it does? I have the very basic knowledge of crossovers but i haven't seen this type of crossover when trying to find from different forums.

Second question is about capacitors. I know that the tweeter capacitor is MKT 160V 3,3uF and woofer capacitors 68uF and 22uF are raw electrolytics 100V. Can i use modern MKP capacitors on the smaller 22uF and 3,3uF values or should i stay with electrolytics?

I will be very happy if somebody have time and knowledge to answer these questions. 🙂

Hi


This Mark Bass amp uses a SMPS, which I am working on. Does anyone know the part number of the power supply mosfet driver IC marked as IC5 on the schematic. It is a 8 pin IC (DIP). They have scrapped off the part number of this IC and I am unable to trace it. Please assist.


Thanks

Unique, very very low THD CFA 120/230W amp

This is going to be my next project of the CFA. Why it is Unique? This is only amp, I know, using OIC(output inclusive compensation, or pure Cherry) and thus lowers crossover output stage distortion. I did simulate similar CFA amp with lateral MOSFET output, but not yet built( I hope Chris will do real world amp of it soon). This one use all BJTs and triple output. This kind of a compensation was discussed a lot(Cherry wrote an article) and D. Self said in his book that is not possible to make practical amp with this as it's to unstable. I think opposite, it is very possible and it should be done. Here I use OIC in combination of the shunt compensation(actually two shunt compensation) and in simulation the triple does not need additional internal compensation, at list in the simulation.
As I think that most people will satisfy with 120 W/8 ohm, 230 W/4 ohm I used only three output pairs. This amp has THD at all frequencies and all powers below 7 ppm, and THD1k below 2 ppm.
I did try different IPS, and going always back to the Baxandall pairs at the input, with diamond input I gain nothing, simple diamond or bootstrapped, and here I use CCM in combination with the Hawksford cascade for the VAS. It is possible to simplify the VAS and not loose in distortion level, and I could show the simplified version too.
Distortion harmonic distribution is quite benign and this is a way to excellent sound. It is DC from the input to the output using DC servo to kip output DC offset below 1 mV. I was trying different ways to connect DC servo with as less as possible influence on the signal path, and thanks to OS I choose this way I used here.
This is just a study as I intend to add all needed protection. First idea is to use capacitance multipliers for the output stage with a protections incorporated on the same PCB and this I've use in my TT amp and it works flawlessly. Other idea is to use output transistors as protection units(not standard current limitation, sound influence is to bad) and not yet sure how to do that.
BR Damir.

Hi everyone I need assistance identifying a blown smd ic by the power supply section

There are 4 powerfets and 2 banks on the amp IRF3205(but they're not in the amp,I took them out)

Readings were taken with the blown smd ic removed.
On the blown smd ic
Pin1 and pin 2 are receiving 12v from the battery + but not directly, the voltage is buffered by a transistor
Pin 3 runs with a 10 ohm resistor to the first bank's gate.
pin 8 is running with a 10 ohm resistor to the gate of the power fets in second bank.
Pin 7 is ground
Pin7 runs to the source of both power fet banks
Pin 5 runs to the E2 on the tl494
Pin 6 runs to the E1 on the tl494

Good day!
Would like to ask if you can help me.
I am looking for all information regarding old Philips DAC Series:
TDA1544;
TDA1543;
TDA1545;
TDA1387.
I'm interested in all kinds of technical information, technology, history, technological differences compared to TDA1541.
Maybe you know the sources where you can get such information.
Thanks in advance!

A question or two to those who have used this FDA in non-ADC applications. I'm building a preamp/volume control for a listening system.

I will be running it on +/-5vDC supplies so the bias will be 0vDC. Since I am not trying to force the COM pin to particular voltage other than ground I am trying to figure out what to do with the pin. The data sheet says, "For a VOCM voltage at mid-supply, make no connection to the VOCM pin." But later says to "Depending on the intended application, a decoupling capacitor is recommended." I have seen implementations that are mid supply and ground biased with the bypass cap and others with the pin tied to ground. Tying it to ground makes the most sense to me but I wanted to ask what others had done. 😕

Second question: How high of a resistor value can I use and keep the chip stable? I'm using the chip as a unity gain buffer that create a differential signal from a single ended signal and I'm trying to keep the input impedance high. Is 10k for the input and feedback resistors too high? I know noise will go up but 1k or 2k2 resistors seem too low for an input impedance. I just wanted to make sure the device is stabile with higher resistor values.

Thanks in advance,
Brian

Hi,
A bit of background to my question. In my country (India) Elektor stopped publishing about over a decade ago. I rarely missed my monthly copy of it and retained ones with audio amps by Ton Giesbert and T Giffard. And now other local electronic magazines too are hard to find at book stands. I prefer the printed copy over online.

But it looks like the printed versions will not be available as is the trend, there arent many buyers I guess 🙁. There are many sports, social, audio magazines that also ceased and are a thing of past now.

So whats my problem with online? For one there aren't many that I know and even if they are there today they will vanish tomorrow. It wont be wrong to say that printed copy of magazines last more than the online counterpart.

Since everything is turning online, please post list of online electronic magazines (audio or general), if any, preferably free.

Thanks and Regards,
WonderfulAudio

Please,can it to produce good sound car speakers in home? I know that speakers most have property box.If sensitivity is 92db what is difference between car and home speakers,and what kind of quality produce car speakers

Hi Folks,

I have an old TU-8200 I built around 10 years ago which developed an intermittent channel issue a couple of years ago which now seems permanent. It's an odd failure as you'll see so hopefully someone has an idea of what's going on.

The setup:
Source is a new laptop or android phone via stereo 3.5mm jack to either the 3.5mm stereo input on channel 2 -or- the 3.5mm stereo input on a BBE sonic maximizer 282i. When the BBE device is in the chain, a pair of RCA cables from it's outputs to channel 1 or channel 2 on the TU-8200. TU-8200 uses tung-sol 6550s and JJ ECC802s tubes in ultralinear configuration. Regular speaker cable to a pair of Klipch bookshelf speakers.



When connected correctly, with and without the BBE device, there is sound out of one channel only(R). when I swap the RCA cables so that R=L and L=R, the sound moves to the other channel(L).


When I pull the 3.5mm cable a bit out of it's jack, in either the BBE input or the TU-8200 input, I get mono sound out of both speakers, though there is a bit of hum as well.


I've swapped cables, BBE devices, and tubes with the same result. I opened up the TU-8200 and inspected for bad solder joints, repaired a few questionable ones. caps all look fine as well.


So, what am I missing? I'm pulling my hair out on this one!

I was using my amp today, and after about 6 hours, suddenly the volume dropped to a very low level. I turned down the volume, switched off the amp, and a few minutes later I turned the amp back on, turned up the volume and everything went back to normal with the volume. I am not sure why it happened. I usually use my amp 6-8 hours at a time. Has anyone else had this issue?

One of my DACs uses a 6th order (Butterworth?) digital filter. What would this correspond to (apodizing, linear phase slow roll off, minimum phase slow roll off, etc.)? And what would the impact be on the impulse response?

Hi,
i have built the Rod Elliot Project 113 HPA and now would like to have a simple delay and DC protect for it.

Please suggest to me simple DC Protect and Delay.
By simple i mean with common components and through hole parts.

I have the pcb but no circuit for this AD797 line pre-amp.

Can anyone direct me to, or supply a circuit for this please.

I have a Kicker zx650.4 that has no power at the ic. Several NPN, Pnp 2n4401/4403 transistors have legs have rusted or corrision where they broke the legs right off.
Q12 the silk screen is missing and was wondering which transistor is used here and in which orientation a photo would be helpful of this area.

Any thought of this as VAS transistor , will be comparing against KSC3503.

TSC497CX

Hi!

I am searching for reviews of Seas Trym kit. Can you help me?Have anybody these speakers?

Thanks

Best regards

FRank

What would cause the same bank on all of the transformers to blow their fets? Output section appears to be fine which has me wondering what happened.

Hi I want stream hi res Spotify through my sound system on a budget, I am looking at using the Yamaha WXAD 10 MusiCast in link below. It has a Burr-Brown DAC. I'd be connecting it to my Sony STR-DG820 home amplifier. It is a 12 year old digital HDMI amp.

Currently when I play music I have to turn on my tv and use my Chromecast ultra 4k and stream to it that way through my Sony amp. With the Yamaha WXAD musicast I won't need to use the TV and can plug it straight into amp. Would it also have better sound quality this way than using Chromecast?

I'd be streaming from my phone a Mi Max which rates as excellent when connected to an external amp in test below. I'm not sure of the best way to do this? There is a lot of rave about the raspberry Pi4 but I think that is only when using a PC.

Xiaomi Mi Max 3 review: Lab tests - display and audio quality, battery life, speaker loudness

https://www.amazon.com.au/Yamaha-WXAD-10-MusicCast-Wireless-Streaming/dp/B077Z9DWYD

Resolved: Convert my blown GK bass head to donor preamp?

I have a Gallien-Krueger rb200 bass head with a blown power amp section -- the preamp section still works using the effects send.

Could anyone comment on a feasible way to use this preamp with another power amp? Pop another power amp into the chassis?

I really liked the sound of this amp compared to more modern solid-state amps and I'm pretty sore that I was unable to fix it. It was $40 so any rat-rod suggestions welcome. I believe it just needs 12v to the preamp board and send the signal out. Am I wrong?

So I have 4 in wall (atmos) speakers off Amazon, built a box sealed done, but temporarily.

My goal was to buy volt 10 for atmos, BUT c19 has caused a few problems,
I did order ht10 x5 and 4 lab15 at the time.
Over a year ago from diysound ground.

So let's try and build a set

Please correct me if I am wrong / educate

My thoughts
- 10" driver maybe 8"
Speakers on list
b&c 10fcx64 or 8fcx51
Eminence kl3010cx ,
what compression driver ?
Open to other ideas,
( goal is a really nice to really really nice speaker)

Box probably like the volt 10
Will try ported and sealed box in winisd

No idea on how to make the xover stuff.


So please educate me
If there is a good post with alot of info please attach

heard on the AM radio this morning -- she caught him using a MAC.

I am working on an amp and I need to supply 3A at 6.3VDC to a 3C24 tube.
I am working from this schematic but I can't really figure out how to physically mount the diodes so they are easily wired up AND heatsink them appropriately.


I'd ideally like to use the chassis as a heatsink but I'm totally open to suggestions.

Any pictures of similar set-ups would be greatly appreciated!

I am thinking of ocp and dc protection circuit for Apex h900 and its derivatives.
If you have any documents can you share? I draw pcb, I can share it on the page.

Hi Folka I recently purchased a really cheap no-name amp from “Banggood” supposedly a TPA 3116 IC Tpa3116 class d bluetooth 5.0 hifi 2x50w stereo amplifier support usb tf card rca aux usb stick Sale - Banggood.com
…I just needed something simple for the bedroom. For the price the sound isn`t so bad but the speakers pop rather loudly on power-up . I`m afraid of eventual damage to the speakers so I`m looking to the experts for a solution. Is there a simple “filter” (spike suppression)? I could use on the line out? I once had a problem with “Hum” on a system and a simple filter solved it, so I`m thinking something similar. Can somebody help me please, I kinda like this amp. Obliged

Hello,
Lots of audio equipment requires regulated, low noise power supply. Heres my attempt to design universal, quiet and relativly cheap power supply for those needs.

The idea of making this project came after seeing this thread. Basically, this is PSU part of my headphone amplifier.
Good old LM317 and LM337 regulators and half wave rectifier. Board can be powered by AC-AC wall wart or transformer. Those wall warts are cheap and easy to use as there is no contact with potentialy dangerous mains wiring.
Voltage at input passes by CLC filter. If desired, inductors can be replaced by 0-10 ohms resistor or even shorted. That would push costs even lower in tradeoff of small performance drop. Regulators are protected by D3 and D4 diodes.
Instead of using more common voltage divider to set output voltage I decided to use zener diodes. Dynamic resistance of zener diode is lower than required resistor which should result in lower output noise. By default 13V zeners yelds about +/- 14.5V at output with less than 10mV diffrence beetwen negative and positive rails. Output voltage can be changed by choosing diffrent zener diodes.

Cadj capacitors are of course present, something from range 10-47uF is recommended. There are two LEDs at both rails. Besides being indicators they run at relatively high current, providing constant load to regulators which keeps low output impedance.
Board measuers 100mm x 45mm. That means cheap PCB fabs like JLCPCB can be used. Latout PDF printed at A4 paper should be 1:1 of board size.
All required files such as schematics, BOM and gerbers are attached to post.

I'm open on any suggestions or improvements.

Hi! As anyone of you ever heard of AES amplifiers? It was in the last decade a very important italian brand, they were designed by Stefano Sgandurra and they has tree gain stages with irf hexfet, seeming to me like the adcom 8002 power amp by Nelson Pass, is there anyone who has any notice?

So I managed to buy a broken SVS PC 4000 Amplifier for repair, This thing is packed with all kinds of stuff. Bluetooth, DSP, Phone App.

I managed to disassemble the plate amplifier its rather rugged/crowed with assembly plates to get to the main parts. I think I found the issues:

- Blown soft start stage.
- Blown Power Factor Correction stage.

I'm waiting on parts but the world is moving slow parts on back order, I wanted to share the parts, build quality of this amplifier is "reasonable quality".

#Configuration.

- PFC Stage.
- LLC Design. LLC
- Full Bridge amplifier (Vent Caps, IRS2092 driver)
- 2 Layer PCB.

#Parts used.

- UCC2863 PFC
- L6599AD (LLC) + LM358
- SF2008 Diode (PFC BOOST STAGE)
- HV MOSFETS P33N60E X 4 + X2 P33N60E Soft Start.
- STM32072 32-bit, m3 core.
- ADAU1718 (DSP, stereo audio codec)
- 100 V, 1200uf caps used. DC BUS. Vent
- 450V, 330uF. (High Voltage) Capxon.

# Parts to be replaced
- UCC2863 PFC
- L6599AD
- HV MOSFETS P33N60E X 4 + X2 P33N60E Soft Start.

I'm looking for a woofer to go from 45 Hz to 1000 Hz in as small enclosure as possible (max 15-20 liter).

Best I've found is a closed box Dayton RS180 where I'll have a -6 db at 45 Hz.
So with a little EQ It'll get there.

Any other candidates? 🙂

Like many others, I have an SAF-40B with a torched OPT. Or I'd sell mine as is.

I've been reading a fair amount but still can't quite get my head around it. JBL CMCD-81 was suggested to me and after reading everything I could find about it I'm now interested. Maybe more so on a CMCD-61. These, however, seem to be quite difficult to source and almost not used by hi-fi enthusiasts...so makes me wonder.

My understanding so far is 2" compression drivers have the great advantage of going up high in the treble (which I don't need), but might sound thin in the 300-500Hz region (which I do need).

Since I'm looking at 350/450 to 2500Hz for the midrange driver I'm wondering if a cone midrange horn might work. Maybe I don't need a phase plug to get to 2500Hz cleanly? What are the cone driver parameters that make it ideal for horn loading?

FWIW, it's an active system with digital crossovers and room correction. The tweeter is a Beyma TPL-150H. I was thinking of a 300Hz Tractrix or a Yuichi-type horn to try and reduce center-to-center distance to the tweeter.

Thank you!

I was doing ok with this today untill i came across, something i dont understand so maybe someone can assit to enlighten me


the 2 ringed vales,both are 0v and not what i expected as this is the the good channel


the issue is with the centre voltage(again @-144mv), which isnt the issue as im working my way through it, its the fact the these 2 values are not what i expected.
Q 602 B/E voltages are the wrong way round on the diagram, but couldnt change the upload before i realised.

Hi all,

I have performed the service bulletin modifications on mine and have a strange issue with the voltage on the collector of the negative regulator pass transistor.

I’m getting +/- 36 volts in to the board ( NB+ & NB- ) and see the raw +38v DC on the collector of the positive regulator pass transistor, as well as the expected 100hz ripple.

On the collector of the negative pass transistor I measure about 28 volts and see no ripple.

The power supply is supposed to put out +/- 25 volts and puts out +/- 26.3 V.

I recapped it as well as installing TIP41Cs in the place of the original SD234 ( TR712 and TR715) pass transistors but am a bit worried about this strange result, any ideas?

Service manual is here: https://www.vintageshifi.com/repertoire-pdf/pdf/telecharge.php?pdf=Yamaha-CR-2020-Service-Manual.pdf

Many thanks,

I recently bought a r-core 30w dual 12v transformer for a pre amplifier board that has dual 12v or 18v in. On input side there are four wires. Black and which I will be using for the 115v and red and yellow green for the 230v. Question is what wire do I use for the ground or do I just isolate the red and yellow green from shorting anything out and ground to the chassis from the iec input? On the secondary’s there are two blue and two brown wires. On the pre amplifier board it is dual 12v-0-12 or 18v-0-18. Question is what wire do I use for 0? I’ve seen it done one wire each for + and - and the other two wires for 0 i believe but I want to be very sure I wire everything correctly so that’s why I’m asking. Any help would be greatly appreciated

I'm still struggling to understand 6th bandpass calculations. To convert a 4th order to a 6th order I simply put a port in the sealed enclosure, right?

But in order to calculate the port size do I treat the sealed portion of the cabinet as a separate enclosure?

e.g. 520 * 340 * 100 = 9 litres gross. A 55 * 170 port should offer me around 65Hz, right?

I'm unsure as to one enclosure's affect on the other.

good, used conditions, runs only in non smoking rooms with no pets
comes with original power supply and the remote control
location is Germany

ask for 380 euros

SOLD

Highest power supply for a dual TPA3116D2 amp

I want to buy the 2021 Nobsound NS-15G TPA3116 amp but i do want 2x100 watt in 4 ohm or close to that since most class d amps has a max power rated at 10% thd, what is the highest i can go for, i know smsl make a 24 volt 6.75 a and nobousound a 24 6a power adapter,supply, is that enough ?

I need a good but cheep input selector (rca) for 4 units, i don't want the cheapest like this, don't like the size,shape of it, anything that can be recomended TronicXL Analogue Stereo 4-Way Input Audio Switch 3x 2x RCA Female 2x RCA Switch Switch Input Soft 1 Output 3 Input Audio Switch Loudspeaker Boxes HiFi: Amazon.de: Electronics & Photo

I have 20 pieces of ON Semi 2SK3703-1E MOSFETs, in the sealed package delivered from Mouser. $40 shipped in the US, $50 shipped to most of Europe and Asia, PM to verify postage).

Thanks-
Ed

For Sale: 100 pcs On-Semi MPSW06
$100.00 + $4.95 shipping

For Sale: 100 pcs of On-Semi MPSW56 Transistors
$100 + $4.95 shipping.

Hi,


I've got a Pioneer GM-2200 amp that I bought recently, it is not working as it should - gives DC voltage on both speaker outputs.

PCB looks ok, I can't see any burnt components.

Any pointers on how to find the fault?
It was 20 years ago since I last did any trouble shooting in electronics, so can't remember much about amps... Would appreciate some help.

Schematics and service manuals:

https://www.opelperformance.se/pioneer/GM2200.pdf
https://www.opelperformance.se/pioneer/GMH100_PIONEER.pdf

Hi,

I'm looking for TOSLINK receiver modules like EAPLRAA4. It seems that everything in this category is sold out when I search DigiKey and OEMstrade.

Any suggestions for RX modules that are available in the hundreds without having to negotiate with traders and parts of unknown origin?

Thanks,
Børge

Hello all,
I need help identifying this part. Came with other spares and not familiar with this one.

Thanks

The last ones from the group buy. now for 12 euro each + paypal+ship

Hello folks, I want to build an audio power amplifier, but not for music use. The objective is to build an AC power supply.


A signal generator that can output between 40 Hz and 400 Hz will drive this amplifier, which will output up to 250 Vrms. The output will be feedback controlled to the adjusted voltage level. As you might guess, distortion and other audio quality metrics are not important. Stable voltage output, good regulation, and sustained maximum power output is important. Initially I want to achieve 1 kVA power, but with the option to increase this as needed.


I looked for circuits online, but the ones I find don't go as high voltage as I need. What kind of topology do I need to consider for this? Valve amps seem to be a nice fit for this purpose, but I neither have the experience with valves, nor can I source any valves here locally. Can you guys point to me to any relevant information on this subject? Maybe books written by the audio greats that touch on this subject so that I can buy that book?

Sold...Noir Headphone Amp

Sold


I built this to pair up with an ACA but, unfortunately, it is not compatible in the way I wanted to use it. I have tested this electrically but have not ran an audio signal through it.
$35.00 shipped. US shipping and PayPal only. Gift/Friends

Hi

I've an old Audio Innovations Series 500 that seems to have gone wrong. I've replaced the four EL84s and three ECC83s and am waiting to get my hands on a pair of ecc88s to complete the valve upgrade programme.

However, I was surprised to find that replacing the 84s had no effect as I'd previously thought that they were shot. I'm wondering if there is some other failed component inside it. I have the schematics but I'm not very experienced with tube amps - just love the sound - and would like to ask if there's anything in particular I should check first. I read somewhere that a particular capacitor goes and that leads to tube failure but cannot remember the details..

Symptoms are as follows:

• 
  Humming (well it's allways done that a little bit, I guess there is a bad earth in there somewhere).
  Very very low output which distorts if you turn the volume up all the way, but stays quiet.
  Phono stage is dead quiet, no output at all.

I guess the first thing would be to test the output from the tape loop. This will provide some indicator for the phono stage.

Can anyone suggest the sorts of things I should look for? What typically fails in these amps? I can post the schematics if it would help.

Thanks

JonB

Hi, this morning I found a Sony CDP-30 CD-player on a fleamarket. Couldn't resist for €2,50. I want to compare it to some of my Philips players. It had been in the rain. I dried it, and when I came home I opened the case to let any damp escape. I dried it carefully with a hairdrier, not too close.
To my amazement, it came to life when I hooked it up. It wouldn't read a cd and did not spin. After I cleaned the lense, however, it does read the disk and spins. It reads the index very quickly and the display is functional and shows the disk content. So, there's actually not much wrong with it, I think.

It plays the disk, but makes a scraping noise that sounds like the spindle is not turning freely. Any suggestions?