Hi, I am going to make a set of 2-way speakers. This is my second project, but this time i started from zero. So I choose these drivers:
1.Woofer: MONACOR: SPH-210
2. Tweeter: MONACOR: DT-107

So the box will be with volume around 30l, poted probabbly triangal ported in 25Hz.What is your opinion ?

And I am having hard times figuring out what crossover frequency to use, the tweeter says 3000Hz but I dont realy like it, what are your sugestions?


Greetings!

Hi all,

I'm itching to try a different design from my normal work, which could best be characterized as high quality PA builds.

The floor-the-ceiling line arrays, made to go into room corners, look particularly good to me.

From researching many line array threads, I've seen that the floor and ceiling are supposed to extend the line's length, perhaps theoretically infinitely...
I take this to be a very good thing...

But I also see more and more commercial column designs promoting beem steering such as one just announced by RCF.. Product Detail - RCF

I get that commercial designs are unlikely to be able to match ceiling height and thus take advantage of extending from floor-to-ceiling. So it seems vertical pattern control could be very beneficial then.

My question is: with a normal 8ft or so ceiling, do you see beem steering such as in the RCF being an advantage?
Or does the non-steered, reflection extended line from the floor and ceiling totally suffice? Would the extended line be harmed be steering?

I realize the need for discrete control of all the drivers in the line...I'm just trying to decide if it would be worth the effort to attempt building in steering capability.
(So far, looking at the usual 3 1/2" drivers... Yikes the channels !!)

Thx... mark

hi got thenutube pcb kit ect, and about to get all the bits n pieces , i have a question would the likes of a 24v wall power outlet like this one
( 24V/2A DC 2-Pin EU Power Supply/Adaptor LED Strips/CCTV/Label Printers etc 2.1mm | eBay)
be ok ? if not could you recommend a similar alternative type ?as getting the triad in the uk you get clobbered with postage thanks

Hello all,
I have changed all capacitor in my Parasound HCA-2200II but not the NP type that sits on the transistor board on the diagram it says NP 10V / 50 ?? but there is a 10uf 80V

My question what is best to replace it with?
the 2 x 47uf is replaced with Elna silmic II 47uf 100v

Regards
Soren

Hi all

New here and I do apologize if I'm in the wrong place.

So I'm working on a soundbar/sound furniture and my very first step is the electronics in this setup.

My need list is:

HDMI arch input from tv
Airplay
Wifi
Room correction.

HDMI input:
HDMI ARC Adapter, ARC Audio Extractor with Digital Optical TOSLINK SPDIF/ Coaxial and Analog 3.5mm L/R Stereo Audio Converter for HDTV Soundbar Speaker Amplifier - Newegg.com
or
Digital interface with HDMI / MHL input to I2S / Coaxial / Optique output - Audiophonics

Thinking this might do the trick

Airplay and Wifi:
WiFi&Bluetooth HiFi Stereo Receiver Board With I2S Up2stream Pro V2

AMP:
TINYSINE TSA7500B 2.1 Amplifier Module Bluetooth TPA3221 aptX 2x100W + 200W - Audiophonics

This might be ok

Room correction:
Any good advice?

Drivers: Looking at some good full-range drivers but am undecided if I should go full range + sub - or mid + tweeter + sub.

The whole idea is to build it into a tv furniture of sorts, and have great movie sound but just as much great sound for music.

This is the first step - how can I achieve what I'm looking for in regards of input from tv, Spotify and process it so I can be sent to drivers.

Please if anyone have the slightest remark for a noob like me, please make a shout out.

I'm moving to our new house in less than a month and the build will hopefully commence there about. Hope to be able to show something that will make other people build something like this as well 🙂

I have Jensen Imperials that I enjoy greatly (with 18" DIY subs, 5 amps actively crossed when all is working). One of my mid horns gave up the ghost. I bought some Great Plains Audio 909 and paired them with Altec 511B. Oddly, compared to the remaining Jensen RP201 horn, the MUCH larger Altec/GPA has significantly less presence in its lower range, say 500hz-900hz. They are almost unlistenable if I cross to them much below 1khz . I haven't actually tested response with signal generator and mic, but it's pretty easy to make relative evaluation since all drivers are actively crossed over. I put the GPA drivers on the Jensen horns and the result was similar. These were my first "vintage" speakers, so I have very little actual experience with horns. I'd appreciate suggestions. Which (relatively inexpensive) drivers might be better suited than these GPA? Or if anyone knows where to get a replacement diaphragm for RP201 that'd be swell...

Need some phenolic spiders, looking around on some websites such as Ebay, Electric market...but could not find where is selling them.

Would you like to tell me the shop that sell the phenolic spider of speaker ?

Thanks and Best Regards,
MichealDon

Hi all,

Is it possible to create a buffer like a B1 with the 2sk170/lsk170 loaded by a J113. Curious if this would allow for a buffer with specs closer to the traditional b1 and not as finicky as the J113 loaded by J113 as in the crossover. But, I'm sure there is something I'm missing.

Looking for some helpful advice on building these lesser known Nagaoka D-99 horns. I heard them in a record store when visiting Tokyo over the summer. The shop owner was kind enough to send photos of the plans, which are all in Japanese. I haven't been able to shake the idea of getting a pair for myself but there are some apparent challenges...

I am not a cabinet maker so I would probably want to contract someone to build the boxes for these. Finding one nearby (DC suburbs) that can decipher the photos I have seems unlikely. Anyone on here specialize in these types of projects or know someone who does?

In addition to the photos below, I also have a very clean PDF of the D-99 ES-R ver. II with adaptions for the FE108ESII driver. I'm guessing the [wiki=[wiki=Fostex FE108EZ]%[/wiki]]%[/wiki] would work too?

Does anyone know if I can create my own drum tracks in garage band and then import them into the BBManager and sync with the pedal? If this is possible will it use the beat buddy sounds?

Thanks!

Hi Forum,

I'm new here, and hopefully this questions haven't been asked before - have tried to look through the posts in this awesome community.

So far I've created my own analog A/B signal switch, where the main signal is from a dynamic microphone. But I'm searching for at more robust/digital approach to this, thinking on using chipsets somehow or is there another "industry standard approach"? 😕

I'll attach some photos of the current build so far.

I have 4 independent mono XLR signals going in the system and then by the press on one of the four footpedals (Boss FS-5U) the signal goes from the output "A" to a sub output "B", without clicking when changing, due to what I understand as a change in the DC?

I must say that I'm not an expert in electronics and my prototype has been build by a deceased tech guy...

Hope to see some nice contributions to my "problem".

Cheers, Rasmus - Denmark 😛

Folks:

I'm no engineer, as we may well soon conclusively determine, and I could use some oversight. I would like to include a bi-color LED as a power indicator in a preamp project and would appreciate some guidance on the circuit I've cobbled together.

A few things to note:

1. The bipolar power supply should be assumed to be always on.
2. The preamp power supply will be off when the preamp is in "standby" mode and on when the preamp is in its "on" mode.
3. The bi-color LED is a two legged device.

My concern with this design is that a short circuit might exist in the brief moment when the preamp power supply is switching between its "on" and "standby" states.

What I like about this circuit is that it's pretty simple, consisting of just five parts (2 relays, 2 resistors and the LED). But will it work properly over the long run and is there a better, more reliable and efficient design?

All input is appreciated.

Regards,
Scott

Hello all


Im from Europe, Malta

Issues coming, DIY Member please dont lol, its not a stupid question !!!

Ita s big problem


I want finished D4k5 and Xlite UCD amplifier, impossibile now !


1. Where can I buy small quantity MICROMETAL T157-2 / ARNOLD MS157060 ?

Mouser, Digikey, LCSC in China, Conrad and Reichelt Germany no have.

Its not available by all big reliable Distributors

Its have try everywhere,

Yes its possibile to buy from authorized Micrometal Distributor, but only whole quantity starting from 500 USD. small quantity or samples not available

Only 1D23A-220M ICE Components 22uh Class D Inductor / 4 USD

ICE Components: We Make Custom Transformers, Current Sensors & More

are available by Mouser

2. Are working 3th party Inductors for Class D available ?

Where to buy small quantity ?

3. Bukalapak- Indonesia and Alieexpress offer something but I dont know its working or fake Inductor, I want buy Original from reliable supplier.

Bad cheap compnents and Class D amplifier not work, same if using Chinese TL071 and CD4049 in D4K5, amp will not work. only original TI

i d like to ask if somebody knows a test circuit to check these ic's..a circuit for example to apply the voltage,input signal,and with the osciloscope check the low side-high side outputs...thanks....

Hey everyone. I've seen on some amplifier builds there are these chassis mount rails where resistors and capacitors are mounted on them for the high voltage components. Does anyone know what they are called? If not, can anyone recommend a way to mount all those components inside the chassis?


Thanks.

Hello everybody.
My knowledge of electronics isn't that high but I'm learning. Fixed other amps before but I've only recently took it to the next level and learned about rail voltages and bought an portable osciloscope. That being said, I'm taking on the power supply first as it had problems and I also managed to short pins 7-8 on the TL494 and I think that one of the transistors went as well, as now I lost even the power I had on the chip. Ordered a set of transistors, I was just wondering if anyone knows what power I should read on the pins of the TL494 and how can I calculate it myself? Also, the FETS are being driven with 5V? As before the short, I had 5V on one bank and about 2.8 on the other, which I believe it was due to another faulty transistor as well. Thank you

Maybe I will create a passive crossover network in the next time for this loudspeaker, but only for the upper two rails (midrange and tweeter) for using a tube amp or single ended amplifier like a ZEN.
The most easy task is the adjustable active low pass for the bass - here I will use a good car hifi version like the syrincs subcontrol II - go to post #5 about
http://www.diyaudio.com/forums/analog-line-level/268053-low-pass-filter-subwoofer.html
More difficult is the appropriate choice for the cut-off frequencies.
Maybe one of the members has performed this already.
Thanks for any hints and reporting of already present experiences in order to several different tweeter models, which are released over the time of manufacturing of the Keltik.
under
http://www.diyaudio.com/forums/multi-way/192988-linn-isobarik-pms-clone-21st-century.html
there is to find a schematic of the Keilidh schematic for crossover network, maybe this is suited, so that only an additional high pass is necessary.

I am new to this DIY audio
I have a pair of 120w fusion speakers (40w at 6ohms) which I'd like to run from a mini amp
I'd like to use an 18v battery to use it portable but with an SPDT switch to switch inputs between the 18v battery and a 19v laptop power supply
Ideally would have bluetooth aswell

Could anybody reccomend an amp/board to use? Thankyou

EDIT **I have just stumbled across this board "TDA7492" which says its 2x 50w at 6ohms, also has a cooling fan on the chip

Anyone have any experience with this combo?

Does anyone know the value of this cap ? I took the pic off another post since my friend is trying to repair the amp and asked me if I knew the value .

It’s circled in red

I am a little stuck with hopefully the final stages of repairing a Luxman L-430. Some assistance would be excellent if someone feels like casting their eye over this.

Attached is the schematic and the full service manualcan be had from here, with a couple of spurious pages for a different amp.

I have replaced one blown output device in one channel and a couple of cooked resistors in both the power supply and the output stage. When analysed statically with a multimeter the problematic channel appears identical to the good, however the bias current won't adjust to any more than 10mA or so.

I am reluctant to poke around with a probe without more idea of where to look, but supply rails appear fine (61V or so), the only difference I can measure between channels is that the voltage on R122 is much lower on the problem channel and LED801 is barely lit.

Some initial discussion of this amp here.

Hello,
I need 4v, I am dropping it from 14v with adjustable smps (buck converter), I also need linear regulator after the smps because of voltage ripple.
The ideal solution would be to use adjustable linear regulator ajdusted to 4v and supply 2 volts higher to it from smps.
But I have L7805CV 5v regulators at home.
I am wondering if I can use L7805CV and supply 4v or a bit more to it and get 4v out without the risk of damage (3.7v - 4.3v is in the tolerance).

Also I have been told once by a member of this forum to add reverse biased diode across the linear regulator if using it after smps to avoid damaging the linear regulator... I did a research, but couldn`t find where exactly to put it, my guess is across input and output pins on linear reg?

Thank you for help

Hey!

So I got one of these weird disc things for about $1.
The seller told me that it's a military grade resistor, and it might be one. I used my 20000 count meter on the 20 Ohm range and couldn't get a usable reading as it was close to the resistance of my probe wire and stuff.

There are a few colored dots on it reading black-brown-black-red-gold-yellow(?), but they don't match the resistance of 1 mOhm or something ridiculously low.
I also couldn't get an accurate inductance reading (with a resolution of 100nH), so maybe not an inductor?
It's not a diode either.

There are a few numbers on it but I couldn't find anything.

I have attached the pictures below.

Thanks!

Hello,

I just received a Marantz DV7600 the other day (That I purchased on eBay.. ok go ahead and laugh.. lol) and upon unpacking her and plugging her in.. Nothing, no power. So I tried four other power cords and still nothing. So I contacted the seller and they swore that the unit was working.. Which, She's so pristine that it's just killing me. So I had started the process of wanting to return her because I just figured the thing is just DEAD! But I had an idea to pop off the cover and check for a bad fuse... Sure enough there is a bad fuse on the power board. On the board it says "250v T2AL", which I got the fuse popped out and it says the same thing.. though in reverse.. I can figure that it's 250 volts.. but I'm not sure about the T2AL part?? And I don't know whether I need a fast burning fuse, or slow, etc? Do I need an "Official" Marantz part fuse for this, or will getting one from somewhere else effect the player negatively. Obviously I want to see if this is just a simple fuse problem, or if there's something more mighty going on. Also.. I paid just over a Buck for the unit.. is this good, and if there's a problem beyond a fuse problem (if it's blows them right away.. is it worth it to get it looked at and fixed)?
Thank you to anyone looking at my post and helping me with commentary. I really appreciate it! Take care out there!

For sale is a Tubelab SE-II 45 headphone amp with volume control (conversion to speaker amp possible, see below).
I recently finished another TSE and have way too many amps and projects so looking to move this one along.

This TSE has been optimized for headphones ranging from 40ohm to 300 ohms (and likely 600 but not tested).
ElectraPrint 5K:32 with 250ohm load resistors to present a more ideal load to the 45 (and to avoid accidental use without headphones connected).

PARTS SELECTION:
- ISO Japan power transformer for extremely quiet, buzz free operation. (I tried Hammond 370EX & 370HX before and the mechanical noise was too loud)
- ElectraPrint 5K:32 output transformers
- Neurochrome 21st Centry Maida HV Regulator for ultra-low PS ripple. This was essential to get hum free operation. Standard CLC and even CLCRC had audible hum with Senn HD650, 103db sensitive headphones.
- DACT CT2 20K stepped attenuator
- AudioCap PCU Copper Film & Foil 0.1uF coupling caps
- WBT-0210 CuMs Topline Nextgen RCA sockets
- Audio Note Nickel Plated 4-pin sockets
- Takman REY and TKD metal-film resistors
- Test sockets on rear panel for setting 45 bias. Pre-drilled holes for 5842 test sockets.
- CNC-milled chassis from Landfall Systems
- Kimber TCSS and Mogami coax wiring

Chassis dimensions: 15.5 (W) x 11.75 (D) x 3.25 (H)
B+ set to 285V on HV regulator.
Biased at 32mA, I measured about 1W, 3% THD to 33ohm and 250mW, 0.95% THD to 300ohm.
If you remove the load resistors, you can squeeze out 1.7W, 3.5% to 33ohm, and 283mw, 0.7% THD to 300ohm.

In this configuration, parts alone would cost atleast $1650. I spent over $2K along the way due to components not be sufficiently quiet for a headphone amp (such as hammond transformers, choke, ASC PS caps etc)

I am asking $1450 including a full tube set: National Union 45's (matched), Amperex Gold Pin 5842 and Sovtek 5AR4 (easily worth over $100)

SPEAKER AMP CONVERSION OPTION:
- If you would like a 45 speaker amp, I can remove the ElectraPrint OPTs and you can fit in any other 5K:8 ohm OPT in it's place. In this case, I will include a new blank front panel and deduct $200 from price. You will have to drill holes for speaker binding posts in the rear or side.
- If you don't need volume control, I can remove the the DACT and wire the RCA directly. In this case, deduct $150 from price.

Other notes:
- The PT is not compatible with 2A3, but with minor modifications this can be converted to use 300B's. That said, the B+ would be rather low.

Thanks for looking, feel free to ask any questions!

In a second-order filter, it is usually seen the reversing polarity of one driver assuming the 2-way system. Mostly, it would be a tweeter. Why the tweeter, not woofer? Could anybody please explain the reason?

I have just started recapping the board and noticed that the capacitors CG13 and CG14, and CG14 and CG16 were switched on the board when compared to the schematic and parts list. Strangely enough is that the marking (circle around the capacitor) on the board fits the size of the capacitors when swapped.

Is it simply a misprint on the PCB and should I swap the capacitors (ignoring the fact that the original capacitors were swapped around, perhaps by mistake?)?

Perhaps the attachments will make it clearer what I am trying to describe... 😛

Hello

Anyone would have the schematic of the Rega Brio-3 amp ?

Even a schematic with no parts value.

Thank you

Bye

Gaetan

I try bougth Wayne's BA 2018 linestage, got this error (Your cart has been updated and the items you added can’t be shipped to your address. Remove the items to complete your order).😕😕😕

Anyone have pics of the power supply driver area?

Or happen to know the value of the resistors ?

During this down time from work I, like many of us, have some free time on my hands. I've always like the look of the mini line array like the Nonsuch4 by the now gone Seventh Veil Speakers. I completely understand now what the articles said about the Nonsuch4. These things are pretty good sounding with nothing more than wiring them in parallel/series to get an 8 ohm load for the amp. I used some Fountek fe87 3" I had bought years ago to do such a project. I recycled an old speaker cabinet by cutting out the front baffle and leaving enough room to screw the line array to it. The cabinet has a 2" port 4.5" long. Once again I am totally surprised by how good this one speaker sounds as my center channel speaker. It obviously didn't sound to good in a horizontal position but was short enough to stand vertically in front of the home theater amp below the tv. No filters/crossover of any type. I have enough of the fe87's to build to floor standing speakers and a proper cabinet for the center channel. My wife even commented that the new center channel replacement sounds pretty good. More to come with some proper cabinets later for proper stereo testing with a dedicated subwoofer.

Mini Line Array kinda

Another kinda Mini Line Array

Not sure why the links are doing this. Something with google photos I guess. The link works for me.

Edit: I was hoping there would be some interest discussion as to the actual science of choosing crossover points but I can see that's not welcome here. Sad.

Recently I purchased an Ashly FTX-1000 off eBay auction. Upon arrival, it became clear that this amplifier had suffered a catastrophic failure. See attached photos for more information. The seller was excellent, refunded the cost immediately and apologized. He did not want the amplifier back.

I do not have schematics for this amplifier. If anyone does, I would be interested to see them. The module that failed had 4 2SK1058s, all of which are shorted. This leads to question #1:

1) Did Ashly use a Quasi-complimentary output stage with lateral MOSFETs? That seems like a very odd decision given the fact that an excellent compliment (the 2SJ162) exists. If they did not, then it is possible that the failure was caused by a previous service. I can't tell if it has been serviced, however, since any evidence has been burned away with fire.

More information will be posted as I get further into this. I will likely try to clean the destroyed board in some way so I can (hopefully) get a better idea of what parts are charred and what parts aren't.

Unless I can source an FTX-1000 output module before I have a chance to cannibalize this amp for parts, I have no intentions of fixing it. I do not currently know if the main power transformer has suffered any damage, or if it's just dirty.

Interestingly, the sil-pads are still intact! This should answer any questions about whether sil-pads are biodegradable since everything else in the area has pretty much rotted away. I suspect that this amplifier has been sitting for quite a few years since it has almost no smell.

Edit: No, COVID-19 is not the reason it doesn't smell, as I can still smell the dog from from about five feet away.

I am trying to manually solder parts on a 4 layers board I designed myself; it's the first time I'm using a 1mm thick board. Don't mention "reflow", I got burned too bad to try it again.

3 out of 4 layers are essentially ground planes. Parts are small 0402 and DFN. I soldered such parts using both hot air and my Metcal tools many times, an 2 layers boards 0.8mm thick with ground planes countless times, without any problems.

Now I hit a wall. Nothing solders properly, 63/37 doesn't flow and wet any pad via connected to ground planes, even with the hot air tool set to 420C, which is huge for Sn/Pb. The otherwise excellent Metcal tools also don't melt the 63/37 in those pads.

Obviously it's a heat dissipation issue, these little boards (2"x2" so far) appear to be excellent heat sinks, and I would expect even worse as the board size increases. The obvious solution is to use a hot plate preheater, and I'm ready to invest in one, but which model? There's plenty of models on EBay, but quality is ???, while a Metcal model is rather pricey and is very basic. Anybody has any experience with these tools? Not expecting any boards larger that (say) 6"x4".

I'm designing a power amplifier with tone controls to be fed with the output of RIAA preamped MM cartridge signal. The signal level after the RIAA preamp is about 500mv and the 3-band tone controls can either cut or boost the treble, the mid and the bass. Upon boosting, it can give out about 2.6v @ 20Hz, so, can the STK459 handle such voltage? This circuit I intend to use is based on the above figure with the NE5532 instead of the TLO32:

Two days ago, while the 9038Pro/Mercury was playing, I touched the volume control knob, volumite, and the playback went to the right channel only. Turning the control all the way counter clockwise gave some left/right playback. I killed power to the whole box, BBB/Hermes/Cronus/9038Pro/Mercury. Re powered and the vol/control functioned normally. This has happened before, static discharge when touching the dac box. So, I discharge my body by touching an unconnected preamp first, forgot this time.
Fired up the system today and thought, this just doesn't sound right/good! Kind of a distorted blurry sound, best I can describe it.
Switched in different amplifiers, no difference.

The clock on the dac board is un-powered, clock comes from the Cronus.

-ICHIBAN

Hello friends There are 2 pairs of 2sk413 and 2sj118. I'm looking for a scheme that I can use them. Is there a circuit diagram you can recommend

IRLB3813 and IRFP7430 Triode-curve

After drooling over unobtainable (for me) Pass SIT jfets and expensive hard to get Sony and Yamaha SITs I looked around at some normal switching fets from IR for an extended range of voltages with typical Triode character.

The IR part IRLB3813 has an distinct Triode curve starting at 5 volts and increases to 20 volts or so.

They are cheap and easy to get, and the 30 volt rating is plenty enough for my 25 volt power supply. I bought some of them and replaced my old IRFP150 in an no global feedback power-resistor drain-loaded Zen amp i am experimenting with at the moment. The result is quite astonishing....

At 10 volts D-S over the fet it has a lot of distortion and sounds quite terrible.
With 8 volts D-S and a 0,75 ohm source-resistor it sounds very very nice. Very present and alive. It is a whole new amp compared to the laid back and comparably mellow sound of the IRFP150.

Even though it has a Ciss of 8 nF and needs a low impedance output preamp it does not sound harsh. There is no lack in highs. It sounds like a very powerful 20 watt amp, and i am quite astonished by the amount of power it can produce. The amp should be able to output 1,5 watts, but it sounds like it has 20 watts or so. I know it does not. Today my kids told me they could hear the music through the walls of our house. They were standing next to the running car outside and was worried it would irritate our neighbors.

Hello everyone, I am new to the forum and new to the tube amp rabbit hole. I have been looking for my first tube amp project and I'm thinking about this one. My question for the extensive diyAudio knowledge base, is this worth rehabbing? I can pick it up for $80. Thanks for your help, Rob.

Hi Guys wondering if there is some advice on this amplifier and the phono stage.

A friend asked me to look at an amplifier that seem to hum on the phono stage. Now all I have is DJ decks and I plugged them in and indeed it hummed.

I swapped round the cables and the hum went from left to right channel. So I presumed its my decks and I swapped it for the other deck and still the same. I was now puzzled as it seems to indicate I have faulty leads/decks so I then accidentally removed the the separate ground cable and the hum completely disappeared.

My DJ days are done but I remember it only used to hum when the ground cable was NOT plugged in and not the other way round!!

Is this normal?? Any advice from someone with experience on this would be greatly appreciated!

I noticed something missing from the straight-through amps I have built then realized my RCA Pro Series receiver (2004 vintage, I still have it) has DSP and spatial expansion functions that greatly enhance the audio ambience. There are other things to decode from CD's and maybe MP3's also, so unless I use my DIY amps as repair blocks for a system with that stuff built in, I will have plain "boring" audio straight from a CD player.
I found only a few enhancement IC's such as the hard to get TDA3810, JRC NJM2701, and QX2020 plus some more advanced chips that look to require some extensive DSP knowledge to work with.

The TDA3810 by the spec sheet causes as much as .1% distortion, NJM2701 either 3% or .3% I couldn't read it well, and nothing found on the QX2020.

Has anyone found and analog spatial expander IC's that are easy to use and cause little distortion ?

After a successful design of a high power bass amp with GU50 I wanted to find out some nonstandard application possibilities and limits for this tube in UL mode . The resulting application might be useable for a bass amp again or a hifi power stage. I want to share the results here. It is a translated short summary of my contributions to that topic posted in this German FORUM . It might be interesting for some of you.

First let us have a look to the tube itself. It is a “real old style pentode”; the screen grid (G2) is not in the shadow of the control grid as in beam power pentodes. What is the consequence? If the plate voltage is lower than the G2 voltage than the G2 current in much higher than in a beam power pentode like KT88. Taking into account the maximum allowed G2 power dissipation we can expect a lower maximum G2 voltage than e.g. for a KT88. Looking to available application data from LS50, E/FL152 and GU50 (they are all the same type of pentode except for the heater voltage) here are some observations which confirms this assumption:

1. In PP pentode mode up to a plate supply (Ub) of 400V the G2 voltage (Ug2) is limited to 250V
2. In PP pentode at Ub=600V/800V Ug2 is limited to 300V
3. In PP Triode mode Ub= 400V is allowed
4. In a LS50 report there have been shown static data values for triode mode with Ua/Ug2= 800V

Some conclusions/observations
- For higher Ub (basically > 300V) we need a separate UL winding for G2)
- Ug2 up to 800V is possible

Using these constraints I have made a test circuit with a PP UL OT having a separate screen winding (20%/40%). MOSFET drivers allow to drive the powerstage with AB2. The plate supply (Ub) is 800V, the screen supply is switcheable between 400V and 600V.

The results:

Case 1) (moderate)
Ub=800V, Ug2=400V,Raa 7K8,UL=20%, AB2 with NFB. The output power is about 120W.
G2 is not going red what I have expected. The first scope picture is showing the result:

- at the upper scope : Ug1 and Output at 7,8 Ohm
- at the scope below: Ua and Ug2

You can see on the scope picture the voltage ratio between the plate voltage (Ua) and Ug2 caused by the UL mode. The duration of Ua <Ug2 is limited, as well as the voltage difference.

Case 2) (aggressive)
Ub=800V, Ug2=600V,Raa 7K8,UL=40%, AB1 with NFB. The output power is about 120W.
A scope picture and a distortion measurements are attached. Again G2 is not going red, as long as we are at AB1. (Ug1max=0V). I have done some “duration tests”, several hours running at full power. The power stage has shown stable behavior.

I personally might use case 1) in a bass amp and case 2) in hifi applications. I know that an UL OT with separate G2 winding has some obstacles (cost, complexity etc…). For myself I have learnt something about screen behavior of the GU50 in UL applications with separate screen supply. Looking to tubes still in production: I would expect a comparable behaviour shown above if I would do the test with EL34 – as long as the tube are from a reliable manufacturer.

Hans- Georg

It's been 16 years since my last log in so go easy on me. I'm looking for a suggestion for a sub?

What 10" sub will fit a .9 sealed enclosure with a mounting depth of 4.75 inches? It will be on an old Punch 500 (500 rms x1 @ 4 ohm or 250 rms x2 @ 2ohm). I have two enclosures.

I don't know anything about tuning I just want what I have to sound as best as it can. It's in an old antique truck, not trying to win any comps here or break the bank... Any suggestions for a sub?

hello
i have wharfedale sys 5000A amplifier with loads of of burnt out components in the pre amp section.
has anyone got schematics for this amp?
many thanks in advance.

Looking for some feedback/suggestions on my scheme for regulating amp rails and voltages for use with OP Amp IC's. The current needed for the IC's is less than 30mA. The use of the MC78 and MC79 are for both buffer and also that I can easily swap them for even lower voltage output units for use with a wider range of LDO that follow them. In actuality, both U2 and U4 will be on a separate PCB that will be fed from U1 and U3.

Thx
S

Having spent many years tinkering with and repairing solid state amps, the lure of building my own amp has been lingering. I originally intended to build a solid state amp from scratch but the quad 606 clone I was planning isn't really all that unique amongst what I already own. Looking for that "something different" to build has drawn me to the dark art that is vacuum tubes. That and a work colleague who has been restoring his old leak TL12's. Having spent the last week or so looking at various designs, I can see that it's quite a deep dive to get into.

Based on what I currently have and use (inter-M R300+ and Tannoy 10" super reds 91dB/W anechoic in a 9' sq room), I reckon a push pull design in the region of 20-30W is probably the most sensible. From that I came up with 3 options that are all pretty similar:

1. Mullard 5-20
2. Claus Byrith 4-30
3. Pete Millett Uniamp

Transformer wise, I've been looking at Primary Windings, VVT, Sowter, Hammond, Toroidy and Lindahl. The standout for me so far is the primary windings offerings for both the mains transformer and the output transformer as they offer a good discount when ordering two items and the specifications seem pretty good. VVT and hammond seem similar. Sowter and Lindahl are no doubt some of the best but cost a bit too much, although the lindahl LL1663 output is reasonably priced. Toroidy I'm not certain on as toroidal transformers don't seem to be common in valve outputs. Edcor can be bought in from the EU with semi reasonable shipping cost.

Valve wise, I'm thinking of sticking with JJ tesla parts that match the designs. They appear to represent good value and, based on what I've read, are supposed to perform very well.

What I'm trying to work out is whether any one of these designs is definitely the superior. From what I've read, the primary issue that I will see is one of input sensitivity. I use a marantz AV7701 preamp, currently utilising the balanced outputs. The millett amp is obviously going to be the most expensive as I have to factor in the need for both the pcbs and the sowter phase splitting transformer. I did wonder whether I could simply omit the sowter transformer as I'm already using a balanced signal but then if it were possible, I'd lose the galvanic isolation it offers. Is the uniamp design worth the ~£200 greater outlay? Is the CB 4-30 a big improvement over the standard mullard 5-20?

I have a 120 V transformer that looks like it has dual center-tapped secondaries (image attached). Hoping someone can answer the following for me:

1) Can I parallel the secondaries and use this transformer as if it had a single center-tapped 24 V secondary winding?

2) If yes to 1), do I get 24 A, making this a ~576 VA transformer?

3) Anything I should know about the 3 V and 7 V windings?

Thanks in advance.

I built a 20w gainclone some years ago I believe it's an xk202 module, don't remember the chip model. I was going to sell it then thinking what can be bought in a nice solid aluminium case for very little I wondered what people think about a gainclone compared to a T amp or other similar amps

So, recently I did some work on a board, and to my surprise it was a very negative experience. I needed to desolder a few through-hole components, a task I have found easy in the past, and it was not easy at all, with plenty of damage to the traces. It was a hybrid PCB with both SMD and through-hole. I suspect my secret-weapon desoldering tool, one of old ones with a rubber squeeze bulb on it, struggled with Pb free solder or cheap PCB substrate or cheap cladding. My soldering iron is also cheap and long in the tooth.

So what is out there for me to look for? Think cheap. Thinking both of the auction sites and also used Weller stuff. These are sometimes on online classifieds, but I don't know enough about how to mix and match irons and stations sold separately.

I still have 0 X TU-882R , 0 X TU-H80 and 2 X TU-882AS. I want to sell these amps at my cost.

During these unprecedented times, I want to provide individuals a productive, rewarding hands-on activity to do while safely staying at home.


There are so many reviews about this amp

ELEKIT TU-822R

REVIEW: Elekit TU882 tube headphone amp: assembled | Headphone Reviews and Discussion - Head-Fi.org


REVIEW: Elekit TU882 tube headphone amp (kit and assembled) | Headphone Reviews and Discussion - Head-Fi.org


TU-882AS $325
Made in Japan

Stay Safe.....

So, I am upgrading the capacitors in the crossover of my speakers. Most of the swaps have been straight forward, but there is one on the midrange that I'd like some advice on. There are 3 components parallel to the woofer; (From Positive -----> Negative) a 10uf electrolytic, a small air core inductor and a 5w 0.27 ohm wirewound resistor. Normally a Zobel Network is just a capacitor and resistor right? Is this some sort of phase alignment network? Anyways, I've figured that I need approximately 0.3 ohms of added series resistance if I replace the electrolytic with a polypropylene film. My question is, does it matter where I add that resistance within the 3 components? For example, should I add a 0.3 ohm resistor before the film capacitor, after the film capacitor, or just increase the original 0.27 ohm resistor to a 0.56 ohm, or does it even really matter? Thanks!

Ay
I have 2 of these Baldwin amps.
I hope to put one in a solid state Leslie.
The other?
It is 3 amps in one and I thought it might make a nice audio amp.
Guitar amp?
Any info or suggestions would be appreciated.
A schematic would be great.

Hi all,

I'm running PulseAudio Crossover Rack software on Raspian Buster & I'm experriencing horrible digital distortion when I loopback audio in PulseAudio from source back to a sink - but only when using samplerate's over 88.2k.

This happens whether I'm looping back from the input from my HiFiBerry DAC+ ADC / from a cheap USB Soundblaster input or a S/PDIF input... The strange thing is though that it plays perfectly for a few seconds, then the distortion kicks in. It's not a digital saturation type of sound but more like R2D2 "bleep-blrrrp-bdleep" almost as though something's falling out of sync after 30s of playback.

I initially thought that it was because I'm running out of CPU but this happens whether I'm using the Pi2B+, 3B or 4. Even the 2B manages loopback @ 88.2K albeit with a few minor glitches here and there.... This is not a huge problem obviously but more of a nuisance.

I'm puzzled because even the Pi3 plays 192k flawlessly with tonnes of headroom whether playing local audio/video sources, streaming DLNA sources, Network streams using PA-Prefs, Bluetooth Audio sources from my phone or laptop. It only falls apart when monitoring from a loopback source, and only when over 88.2k.

Does anyone know why this occurs?

Thanks,
Darp

hello
i have had this mini hifi for several years with no prob.a week ago the display turned off and doesnt show anything....any thoughts where i should look??

Hello everyone

I have in my possession, to repair this amp, but I do not have his partner ST-CA 1080.

Well, when you connect it, nothing happens, no sound, no lights on in vumeters or standby mode, despite pressing the power button.

I checked voltages at certain points of the circuit on the motherboard, and I've seen different voltages at various points, which leads me to determine that it is not the power supply.

I made the connection bridge TP701 which forces the amplifier to turn on.
By doing so, power relays are activated, and the lights of the vu-meters are on, but nothing else works.

I have checked many components of the motherboard (resistors, transistors, diodes, capacitors,) and I have not found any that are wrong.

Any ideas of where to look?

Any help will be appreciated.
Thanks in advance.

I've been playing with Hornresp modeling compact offset bass horns for HT use. Design parameters are a sub that goes to about 120dB from 20-150hz in as compact a space as possible - I have a 22" max width restriction. I'm planning on building two subs to be placed in the front room corners and external proamps plus MiniDSP equalization would be utilized.

After modeling several different 15" drivers, the Dayton 15" Titanic seems to produce the most dBs and the smoothest frequency response for very small enclosures. Attached is a Hornresp design I ended up with and a preliminary layout, which ended up being about 2.5'x2.5'x2'. I've designed and built several different types of speakers before, however, I've never built a bass horn. Do any of you experienced horn builders have any feedback or comments about the design?

Thanks,
Vince

Hi everyone,

Long time reader, first time writer.

Through work I have happened upon heaps of old UPS units from a disused data center. The units are ridiculously large. They measure about two double fridges in width. That does not include batteries as they were connected to two banks of batteries that each took up a room the size of banquet halls. 😱

Is there any parts in such equipment that can be used for diy audio?

I opened one of them and found, among other things, a bank of 54 electrolytic Epcos capacitors rated 500v 3900uF. They are, as everything else there, huge. If size is not a problem, can these be used in a power supply for a power amp?

There was also a “ABL8RPS24100 - AC-DC CONVERTER, DIN RAIL, 1 O/P, 240W, 10A, 24V”. This can be tuned to put out between 21-28 V DC. Would this be any good for a chipamp perhaps?

Also, there were quite a few large 3-phase transformers, but they did not state any input/output voltage.

Does any of you diy-wizards have any input/insight as to the usability of this?

Best regards,

McLure

This korean half bridge has me stumped a bit.

Previous owner states he purchased the amp, it was playing perfectly, and then suddenly shut down. Upon initial inspection the amp had been previously repaired and im guessing the repair tech incorrectly placed all the mosfet clamps between the fets and the sink!

Consequently ALL of the output fets are smoked and all have been removed. No solder bridges present after removal. Power supply fires up beautifully on 10v. Then the muting relays click off and the amp immediately shuts down (rail voltage is usually around 110v when this occurs).

I then inspected the 12v voltage regulation circuit which employs a pair of TA78t12. One was destroyed showing continuity across all pins. I removed both and measured voltage at the veirs. To my horror, full negative rail voltage was present on the input of the regs at powerup!

I do recall something about some amps using the negative rail voltage as a virtual ground so the 12v supplied to other components is stable. Is that the case here? Or should I not have negative rail voltage to the input of the 12v regs?

Thanks in advance.

Ps Im also having a difficult time finding a replacement for said voltage regulators. Origionals were a 3amp capacity in a to-220 case.

Today I have put together an amp with the Hifimediy T4 Jantzen board that was laying around for ages. I have made a linear PSU for it that runs on about 44 volts.

After let it run for a while and listen to music on a low volume level I noticed that the heatsink on the pcb is getting hot. Almost beyond touch temperature.
The sound is just fine (okay, okay my other amps are Nelson Pass class A amps lol). My speakers are IMF TLS50's

Is the high temperature of the heatsink normal or could there be something wrong?

I forget can’t think today .

Do the 640’s go on the negative rail ? So they see negative rail voltage and the 9640’s see positive rail voltage ?

Every time I have asked someone about that "Black Line" you see on some caps I get a different answer. Some tell me to have the line more positive some tell me to have the blk line negative.

The other day I watched a rather unusual video where the guy was checking his caps with his scope and thought why didn't I ever do that. Watching his video I found out that the line doesn't mean anything. He checked several caps from the same vendor with different results. Could this possibly be why some of us have battled noise when we do a build?

Hi All. Help needed with identification of transistors in attached

S503u has the latest Spiral II DAC.
Left (503 - OLD DAC) Right 503u with Spiral II DAC.

Warranty Repair
The customer is responsible for freight charges to ship the product to us for diagnosis and repair.
If the repair is determined to be covered under warranty, we will ship the unit back to the customer via the same shipping method in which it was received at no cost to the customer.

Hello everyone,

My Nak preamp has a hum that doesn't goes up with volume control. Frequency seems to be at 60Hz, plus to this I can hear something like "radio talking" also doesn't go with volume. Hum is present with no devices connected to inputs.

Sound anyway clean, no distortion.

I've checked power supply, everything seem to be OK +/- 0.2V from Service manual values.

Looks like ground problem, can't find it.

Out of ideas.

Thanks in advance!

M

So I've pieced together components for my Class D amp, including a powerswitch,and I just want to confirm with you that this will work safely, as I'm still learning about electronics. :-/

The powerswitch is rated at 5A.

I've got a Connex SMPS600RS that converts 220V AC to 38VDC.

The Amp board is specced to use 18.1A max current.

The way I understand it is that 19A x 38V = 772 Watt;
772 / 220 = 3.5 ampere.

Am I correct in understanding that the powerswitch on 220V will get a max amperage of around 3.5A, and therefore this powerswitch should be safe to use?

Hi am looking desperately for schematics for my philips cdr mpdel CDR765.
thanks for your help
abes99

salve , qualcuno ha lo schema di questo finale di potenza ?

hi everyone. i have a ep2500 that im repairing. the output transistors are shorted.anything else i should on this amp? any common issues?..thanks!!!

Hey there, I'm Adam a complete nOOb. I have been reading the forum from quite a while and decided to jump on board. I'm going to create a 3d printed sound system on my own. Big ambitions maybe due to Coronavirus quarantine.

Thanks for all your useful contributions and sorry for the tons of questions I might ask you 🙂

Best, Adam

As you may have red, a couple of weeks ago had a problem with (probably) a loose screw that reverted in problems with Q2 and U2. Talking about my loved TSE 300B.
Ended with a bad 300B, now I have new Emission Labs 300B.
Doing all routine checking (175V on 5842 plate, around 60mv on 300B plate..) I discovered a little, a small, an insignificant detail that surely passed unnoticed when TSE was built, 5 years ago : a B+ of 422V
That’s too much….how couldn’t I notice it at the time?

So I’ve begun to re-read info in the thread and understand that correct B+ should be around 390V, I’m roughly 30V too high  so how do I lower B+?

First have reduced C4 from original 20uf to 10uf, B+ changes from 422V to 413V…..good but still not enough and that why I’m asking for your help.

Any suggestion how could I reduce B+?

For example, would it help :
- a couple of CL 90 thermistor on both legs of transformer?
- add another R-C to the C-L-C rectifier after C5?
- add a resistor after or before the choke?

Don’t know, what do you think? Any help will be greatly appreciated.

Regards

g.

Hi. Does anyone recognise this card?
I just bought a player, but i havent got it yet, just a picture. It is digital out, but what is it.

Thanx in advanc
Allan

For fun i bought this tiny TDA7492P module from Sanwu.

TDA7492P Wireless Bluetooth 4.0 Audio Receiver Digital Amplifier Board 50W+50W | eBay

No fancy buttons, mic etc, just plain Bluetooth + Line-In.

The module is not "dead silent", there's some noise, but not from digital domain. Another nice feature is the signal amplitude driven automute-function.

While poking around on the board to get the pinout of the BT chip (sanded down) i thought, the 4 vias at the bottom are something like TTL UART. Well, no, it's USB and the module's enumerating as an USB audio device. 😀

Now we have BT + Line-In + DAC (16bit/48kHz) + Amp for less than $7.50.

A shame that the BT-DAC is SE only.

(The Bluetooth chipset is from "ZhuHai JieLi Technology")

My son got a request to build a suitable box for two Hertz HX380 15 inch drivers. The challange being getting two 0,41 Qts, 130 liter Vas drivers into a box not exceeding 810 X 500 X 480 mm (194,4 liter).

I appreciate bassreflex just about as much as root canal work without anesthesia or dog poo on my hamburger, so that kind of excludes that option.

A straight run of the mill closed box lacks any real midbass punch with this kind of drivers, and any kind of tapped horn or higher order BP ended up at least twice the maximum allowable size.

I have never built a 4th order bandpass before and I like the PPSL type of box, since they tend to sound very punchy, clean and "alive" if done right.

After a few hours of Hornresp backed meditations on the problem I came up with this quite simple to build layout.

We choose isobaric loading to get some real useful Bl to drive the short quarter wave front resonator and to help pressureize the car cabin even at high power levels. The huge Le and high Qts tends to dull and muffle the midbass response when pushing some real power into the driver. Isobaric loading doubles the Bl and doubles the power dissipation capacity of the voicecoils and keeps distortion at bay when needed the most.

Hi all,

This is my first post here. Can someone help me identify the capacitor in the attached image please?

I recently bought a pair of Epos ES22, sold to me as having one with a non-working tweeter. Initially I thought the tweeter was blown but upon closer inspection it could be the capacitor on the negative wire to the tweeter has failed instead. It's possible the tweeter itself is fine: the diaphragm is intact and the coil too. It could do with new ferro-fluid but that's besides the point right now.

I've had the multi-meter to the binding posts and to the bare tweeter wires (the tweeter is disconnected). The red/positive terminal gives me a continuity sound upon testing, but the black/negative does not. As mentioned, the black/neg side is the one with the capacitor you (hopefully) see in this post.

Thanks in advance!

G.

I'm a big fan of active studio monitors and I'd like to experiment with some of my own without totally blowing out the bank. I might eventually work my way up to the Hypex DSP plates, but I'm thinking something similar to the amps in my Adams (20W/50W) or JBL LSRs or something along those lines. Probably asking too much to get DSP in there too, but for experimentation purposes I'm probably happy to just run them off an external MiniDSP.

I know I can get any number of cheap rackmounts, but I'd like to stick to plates. Suggestions?

P.S. Not totally opposed to standalone modules that I have to assemble on a back plate myself, as long as there's good info on the wiring.

I can't find it in the specs..?

Sure Electronics AA-AB35281 3x200W Class D Audio Amplifier Board - T-Amp

I mean, it's a T-amp obviously but I'm wondering what chip.

Ok so I've already got myself a very good microphone for acoustical measurements.
However the standard laptop soundcard is utterly crap you could say.
With an external microphone preamp and amplifier I was able to do some measurements using REW as the software.
Problem is that it is kind of a hassle to get everything hooked up.

So I was thinking about getting a setup together in a 3U flight case that I can take with me and can be used to do some audio/acoustical measurements.
I have also seen ARTA software wich looks really nice to also do some impedance measurements.
I currently used the Dayton DATS V2 for this and this works but would be nice to do some measurements at higher power.

SO first things first I would need a USB audio interface. 19" if possible and would be nice if it has some ADAT capability. (I need to test/repair a lot of gear so this would be usefull for testing gear with ADAT interface)
After some searching I came across teh following:


Behringer umc1820 UMC1820 | Interfaces | Computer Audio | Behringer | Categories | Music Tribe - Behringer)
Price is very low for what it has to offer.
I'm not the greatest fan of Behringer. Bad build quality etc.... (altough the DCX2496 did impress me)


Next up is the Focusrite Scarlett 18i20 | Focusrite
A little bit more expensive. Has higher available sample rate.
The extra input display is also nice as an indication to not overload things....

Ok the extra inputs are overkill for just acoustical measurements but it is the only one that has Adat and it would be nice if I can use it to test some Adat gear.

So next up I would need an amplifier, Resistor to measure impedance and then some connectors/switches frontpanel etc.....
So I have a UCD400 module lying around that could be used as an amplifier. Have some spare transformer somewhere also.
Don't know if the switching noise residue would be problematic for measurements.....

The high impedance inputs of the interface could also be used for some distortion measurements of preamps etc....I do have a Audio precision for that in my lab but it is not that portable for when I need to do some measurements on site.

So any advice is welcome.
I have seen the QA401 and QA460 wich I like but I Wouldn't have ADAT then.

I am starting this thread because the iraud200 thread started to become too long to read and process because of all of the little experiments, discussions, etc. This thread is only for quick reference on how to manage the iraud200 board. Use the other thread for more info. on fine details and more detailed understanding.

I chose the iraud200 boards from an ebay seller because I wanted a 2 ohm capable single channel board capable of handling around +/- 70 volt power supply and 600+ watts per channel. iraud200 seemed to be the only option available for these specs. The next closest runner-ups were the iraud350 which at best handles a 4 ohm load. The iraud200 and the iraud350 are close cousins. That means that they share some attributes and problems.

Both boards have the fundamental problem that they are way over-driving the irs2092 chip. One of my copies of the iraud350 worked, but eventually it was the irs2092 chip that failed. That board had a small, tall heat sink pasted to the irs2092 chip to help with the problem. I over-currented the transistors and lost them and replaced them with irfb4227 for more current, which the chip was apparently unable to drive despite heat sink because the 2092 was the next thing to go. I thought it might work to try a board that carried the irfb4227 stock, so I went for the iraud200 and hoped for success with 2 ohm loads. I was sorely disappointed up front. I really wanted this to work, so I became determined and eventually I successfully forced the board to behave. I would like to share the secrets of this success with other DIYers who see the iraud200 as a potential option to get what they want.

The iraud200 sports excellent protections and current/power capability. The irfb4227 transistors are magnificent and capable of stunning currents such that just two of them can be used to drive over 20 amps through a 2 ohm load.

When my board(s) arrived, I was greeted with obvious Quality assurance failures that made me very suspicious. No heat sink grease on the transistors .. no heat sink on the irs2092 chip. I did not dare power them up until I had the transistors greased and a tall little heat sink on the irs2092 chip. When the parts arrived for that, I was in for yet more disappointment. The boards fired up and worked beautifully for about 3 minutes. Then they quit. I thought they were burned, but actually not .. the boards sport overtemp protection which had turned the boards off because the heat sink had become too hot (imagine what would have happened with no heat sink grease).

Later, It turned out that the cause of the overtemp failure was a high frequency parasite that resonated in the output filter and leaked back into the feedback loop. Before I knew that though, I learned a lot of things about the board in my attempts to beat this problem. To make the list complete though, I am going to list all of the problem of the board including those already mentioned.

1. No heat sink grease on the transistors (easy fix with heat sink grease)

2. No heat sink on the irs2092 chip which can't drive irfb4227 safely without it. Get a small heat sink from ebay or such about 10mm by 10 mm by 35mm and get heat sink glue to glue it on there .. try not to get the glue on the pins of the chip (don't know how crucial this is .. never became a problem for me)

3. The fudgers did not follow the proper feedback loop specs from the example docs. Don't know why, but they made several changes. First, they eliminated the 150 pf delay cap and accompanying 1k resistor (really bad idea) out of the feedback loop. Second, they slightly adjusted the ohmage of the floating ground (no biggie) third, they eliminated the input capacitor and allowed you to direct DC drive this board .. it should in fact be able to output DC current (interesting, may find uses for this later) . You can forget about the DC input/output option they built in pretty much and not worry about the tweaked floating ground except that I think it adds a little hum to the output. The killer is the elimination of the delay cap and resistor in the feedback loop. This exacerbates the problems we already have, trying to drive the high gate charge of the irfb4227 by boosting the feedback switching frequency to around 800khz. It also feeds the parasite OUCH!!!! This thing is trying its hardest to burn out the irs2092. Turns out that the iraud350 does the same thing. If you have either board, you will want to fix the feedback loop.

To fix the feedback loop, order 150pf ceramic caps rated at at least 150 volts and 1k surface mount resistors of the proper size. This board has a single 200kohm resistor that acts as the feedback voltage reducer. You can continue to use it, only you have to put a 1k resistor between it and the transistors output, then connect the junction between those two resistors to ground through the 150 pf capacitor. This slows down the switching frequency and in my case allowed the board to run without overtemping. However, it was still very hot and it made me nervous to run it/them.

4. Interestingly the high temperature would sometimes disappear for as much as several days, which I eventually learned to be a result of a faulty connection between the output filter capacitor (the big one just behind the heat sink) and ground.. or .. eventually ... a destroyed output filter capacitor. When the connection from cap to ground would disappear, the parasitic resonance between cap and output inductor would die with it, the board would cool off, but obviously, there would be a lot of rf on the output line because only half of the filter would be operating.

5. The output filter capacitor was not rated properly. It should have been 0.47 uf and 200 volts or higher AC rated film capacitor. In stead, it was 1 uf and 100 volt, which the parasitic resonance destroyed after a period of time, leaving a board that didn't overheat, but also basically had no proper output filter capacitor. You will need a high power soldering iron .. like 40 to 60 watt to swap that capacitor out .. otherwise the solder won't melt well enough. .. but don't reach straight for the correct 0.47uf 200 plus volt capacitor to replace this with because it's a potential parasite feeder .. see number 6.

6. After putting the correct capacitor in place, the board(s) still ran dangerously hot. I added some resonance dampening caps and a resistor (I'll show these crucial details in detail) .. this got one of the boards to behave, but the second one didn't because its parasite was a little livelier. I tried tweaking multiple resistors in the feedback loop to change this to no avail. That's how I became convinced that the parasite was living in the output filter. Smaller output filter capacitance in the output filter helped cool the board, so I ordered several options of parts to take that output filter cap position. Eventually, the combination that killed the tougher parasite on the second board was a 0.27 uf film cap rated at 275 volts as the output filter cap, and a second capacitor of 0.22 uf (275 vac film) connected in series with 4.1 ohm 4 watt (suggest at least 5 watts for this 5 ohm is probably fine) dampener resistor across the boards two output terminals. (output and 0 volt .. right next to each other) Whala ... success!!!!!!!!!!!! The parasite could not make it past the tipping point, so it remained a virtual nothing of empty space-time.

7 The board has 3 10uf (nonpolar) ceramic caps that help the floating power supply function. These were smaller than the caps on other variants of the circuit I had seen, so I purchased a bunch of 10uf 50 volt and soldered them on in parallel with the pre-existing caps. This is the first parts change I did to try and fix the boards, which didn't work, so I don't know if it's required or not, but it's a good idea I think.

8 There are two versions of this board .. the 4 ohm version and the 2 ohm version. The 4 ohm version has a smaller output inductor. Yes, I know, there are four pins on the inductors which makes them look like pairs of inductors, but two of those pins are not electrically connected and only stabilize the inductor. If you want the 2 ohm version, make sure it says 2 ohms and maybe double check that the inductor is filling up its (square) space all the way ..

9 also, don't get a version of this board with oversized storage capacitors because they'll get in the way of a heat sink for the output inductor. The output inductors are a little small, so to stay safe, heat sink grease a heat sink to them and then when you are done fiddling, replace the heat sink grease with heat sink glue. The output inductors definitely have to have the heat sink to protect them if the boards parasite problem has not been fixed yet. The main heat sinks are likely to require supplementation as well, especially if you haven't killed the parasite yet.

10 Using ferrite beads on the 0 volt lines to the power supply, I was able to get two of these boards to co-exist on a system with two plus poles and two minus poles that shared a common 0 volt line. This normally risks the 2092 chips getting all befuddled with rf on the 0 volt line that comes from the other board, but I was able to smile by simply putting two ferrite beads on each 0 volt line. Yay!!!!!!!!

So, this is the intro. page .. as days progress, I'll get to work making all of this information more visual and understandable.

Hi All,

I'm having some trouble getting my brutefir setup working.

I'm planning on using the optical input and 8 analogue output channels of my X-Fi Titanium sound card for an active filtering system.

The thing is I have no idea how to map the inputs/outputs of the sound card to brutefir. The sound card is detected by the system and works. I can use speaker-test to generate audio output on the first two channels, the rest do not work.

Below is the output of aplay -l

I don't have any setup in my /etc/asound file, I have no idea how to do this. I haven't been able to find any documentation for it.

I have an analogue input and output on the sound card. I'm inputting 2kHz and getting nothing out. My current filter setup is a 1kHz high pass filter.

Any pointers or help would be much appreciated!

This is the output from brutefir when I start it.


These are the input outputs I have setup in .brutefir_config.