Hello. I have a new home Kawai digital keyboard, 120 V input, 2x50 W speakers (but I use the headphone amp anyway, or computer VST), >$4000.

What should I put between my keyboard and the outlet to keep the keyboard well? (Hereafter 'power bar', though that might be misleading.)

Power: I don't really have reason to think the power coming to apartment/outlet will be unreliable, besides storms or rare outages, or that I have fancy protection. I'm not sure how to verify this. (See below: I might have had voltage out of 100v-135v magnitude at some point.) Townhouse, probably suburban.

I assume I should at least get a good enough surge protector--what would that mean?

Currently I am deciding which power conditioner to keep (allowing it to count as a surge protector.)

(Any reasons for/against power conditioners?)

If I had reason to be wary of my power, I might consider an Uninterrupted Power Supply instead, since there is a computer component of the keyboard (I have the keyboard off when not in use). I'm not afraid of power outages particularly, so maybe this would be to protect against brownouts etc. (also likely irrelevant).

One of my conditioners that I'm trying is a Panamax that is supposed to turn off power temporarily when it detects 100v to 135v (I think), and otherwise has 331v clamping with 1575 J protection. It has turned off twice now, presumably because of some split-moment of a voltage problem, maybe because it was mistaken. I assume this wasn't due to a surge, just something outside of 100v to 135v. I don't know.

I suspect that having the Panamax shut off power would be more dangerous to the keyboard than having even a few seconds worth of brownout, and that I therefore don't like this particular feature. However, without the Panamax, I can't detect any problems except surges and blackouts, so if something were going on, I wouldn't be doing much to stop it (except noise filtration.)

I also don't know how this feature alters the effectiveness of surge protection. 135v < 331v, after all. Does this affect J rating, either?
The other unit should have 181v clamping and probably more endurance than 1575 J, but no such anti-brownout/swell feature.

Which of these options might be better?

What should I do now?

And for future reference, when I replace the power bar, what should I consider getting? Some sort of surge protector, some UPS? How can I know what I need?

Thank you.

Hi,

Why couldn't someone make a DIY audio receiver? Licenses,etc aside (not talking about the legal battle part).

Get the HDMI bit stream via some sort of capture card, decode the bitstream, tons of kodi / ffmpeg code already exists to do this, in pre, then virtualize the objects in as many channels/speakers as you desire, hook up a whole wack of cost effective usb soundcards to DAC it out to external amps. Heck 24.2.10. An RPi4 could easily handle this. Isn't hdmi 2.1 audio max 31Mbit/s? That's nothing for a multi-core arm processor with neon to handle for receiver duties.

I mean anyone could easily do all the software, it would be a weekend project to slap together a bunch of open source stuff and do some digital dsp. Just need to get the bit stream via HDMI, there are already those splitters which do the edid/content protection bit and extract the audio stream.

Is there any HDMI->usb capture card that will get the raw audio bitstream coming in? Does anyone know of any?

Hello, although I do not participate much in the forum I am a regular reader.

I have purchased a Marantz cd73.

The player does not work, the drawer opens and closes, the "Laser" led is on and the green LEDs on the top cover light up. But it does nothing else.

You can hear the noise of the drawer motor running, but the arm does not work either.

The recommendations that I have read are about the power supply, I have measured and I have the voltages equal to the diagram.

Someone knows and can guide me where the problem may come from.

The image is borrowed from the web.

Apparently someone at some point made a modification to one of the rectifiers in this Orion HCCA 250r (see photo). Does anyone know why the capacitor would have added?

Hi All,

I am looking for a reasonably priced pair of working XO's for the NS1000M.

I know there are multiples pairs on HiFiShark, but they aren't as tidy as i'd like for the price they want.

Let me know what you've got.



Thanks

Oliver

Or at least I'm calling it Take 7.
It's really the 3rd completely different cabinet.
Other 'takes' were trying out different size ports or different drivers, etc.

They've all been desinged to go with subs at 100Hz like my previous synergy thread 100Hz two-way synergy project.

That thread ended up turning into this 60x40

I've truly enjoyed this speaker, to the point I wanted to build another for stereo, but it's too damn big and heavy to move around. About 100 lbs.
One of the biggest joys in audio for me, is being able to move gear around, listen outside, swap stuff around, always making comparisons and learning.
So I've spent a few months researching how to get the synergy goodness, but shed alot of weight.

Anyway here's the outcome.

It's a 90x60, that has very close to the same primary horn width and height, but of course less depth due to its wider pattern.
It weighs in at a glorious 45 lbs !!!
Uses two dirt cheap faital 10FE200's as mids, and one not so cheap b&c dcx 464 coax cd, ...but getting the CD down to 500Hz is what lets it work.

I did a few things different from my previous attempts that all tried to adhere to the conventional synergy wisdom.
Biggest change was putting the mid ports in the center of the horn instead of in the corners.
I made a test horn where I could block ports easily and experimented a bit. I couldn't find a compelling case for corner ports, in terms of how the HF and VHF were effected.
That was a peasant surprise really, because I wanted the ports in the horn center as part of a weight reduction design. It allowed the mid drivers to go on the top and bottom in small cavities, and the horn side walls be all the cabinent there is.
Like this

Plus, ports in the center of the horn are just plain easier to make 🙂

Also made a simple box to test port sizes and shapes, port thickness, and how much port frustrum matters. Picture a sealed box where you just lay a plate with various port tries on top, and move it around over the cone.
I used plates out of 12mm BB and thin steel sheet, and ended up choosing a 10:1 compression ratio in terms of hole size.
Surprisingly, I could not find anything to beat a simple round hole aligned with the center of the cone.
Neither could i find a reason to use thin ports, or even do anything to the wood hole other than a little roundover smoothing.

The port holes' center is 7.5" from the throat. Basically, the 10" drivers sit as close to the horn apex as possible, which also puts the port nearly under the center of the cone.

I always have to give sincere thanks to BWaslo for his speadsheet....I simply could not make a synergy without it.
Also need to thank Makita for my track saw Lol. It makes the bevel/miter cuts so easy and true...much better than i can do by table saw and sleds.
Oh, I've found I like to make the horn start at 1.4" square, and not have to round out the walls to mate the CD. It's been easier to add museum wax to the horn corners in the mouth.

Syn7 may or may not get a secondary flare depending on outdoor testing.
I should be able to make a detachable flare like in the first pic fairly easily.
What I really want to do is add a tractrix flare as the secondary flare.
Ala the K-402. I figure the K-402 first 2/3's from the throat is pretty much straight sided conical, and the last 1/3 tractrix. A conatrix or a tractical, depending on which end you look from haha

Garage Speaker with one driver

Hi Community,

I am new in this forum / this is my first trade so please be patient with my novice question (I think i did read most of the threads about BLH and also did try to understand it as far as possible ..)

I saw on Thingverse a very nice design for a BLH based on a Visaton FRS 8 M an thought about printing it also for me and use it as an Internet Radio in my workshop (Back Horn Speaker V2.0 BL2 - Bluetooth, Active, Passive by guppyk - Thingiverse).
For this purpose i am required to redesign it bymyself in order to add a display on the front. Then i started to play around with Hornresp in order to understand the theory / relations about it a bit more.

Now i want to ask you guys if you have suggestions if there are ways to make more out of the given FRS 8M or if it's worth to build (print) them. If not i could also go with a Bassreflex design ...

Please find attached my Inputs from Hornresp and also my current design (The area inbetween the driver and the Horn output shall be used for the display / electronics).

The size is limited by my 3D printer (205mm x 205mm).

regards
Christian

Hi.
I have a defective relay in my Sony amp.
RY701 (see attachment)
Any suggestions for replacement?
Thanks!

I've built a HV supply for my DIY hybrid ESLs based on a CCFL xfmr and capacitive multiplier. Runs from a 12V wall wart and produces ~3KV (adjustable). Also has a music sense circuit which can be left unpopluated and bypassed (always on or on with external switch). There is a SMT LED on the PCB to show when the circuit is active and a connector for an off board LED for same.

The PCB is 2.50" x 4.00" double sided; mixed SMT and thru hole.

If anyone is interested in building this, I can make the gerber files and BOM available. I'm not familiar with how to do a group buy, but if someone else wants to run with it, I'll do what I can to assist.

ZD3 was broken and R40 became very hot.

After replacing ZD3, ZD4 R40 and R39 i measured the temperature with heat cam. R40 and R39 become very fast hot. About 120°C(250F).

Is that normal ?

I think the original ones were 5 watt resistors, length: 0.94 inch, diameter: 0.29 inch. 270Ohm.

The amp works fine, but i tested only for 20 min.

I have this center and was curious if I could run one woofer as a mid and the far other side woofer as the woofer. Crossed to a larger planar or ribbon tweeter 8” or under.
This current center used the same 6.5”
Woofers, a 4” midrange and a metal dome tweeter.

Has anyone ever made a center channel with one one of the woofers running the mids?
Would this work better then the current setup? I really wanted a better tweeter and these woofers are pretty cable of both bass and midrange.
The midrange is this same speaker but the 4” version.
http:loudspeakerdatabase.com/Peerless/HDS-P830990

Hi needing suggestions for a capacitor replacement in my crossover. The cap pictured was what was originally in my speakers (Mission 734). I replaced this electrolytic cap with a polypropylene cap and found the sound improved in terms of clarity but became harsh/brash. The replacement cap was a custom designed one that id like to replace with a good brand. Can anyone recommend a cap that will sound softer like the original cap but still offer the improvements in other areas. Please name the brand and cap value that i could use as i dont understand the writing on the cap pictured. Thanks

Anyone have any pics of the board in this amp ?


Someone cut out caps and there are 2 wires on the bottom of the board that I don’t know where they go

I’m assuming the 4 caps are 0.001

my amp is power up, i'm getting harmonic sound, when i put an input jack in and a bad humming out the output. need your help please. thanks i try to up load schematic.

Hi, I bought a Denon avr-1913 receiver used and the left surround channel is low and noisy. I have been doing research and I'm trying to test and see if it's the output transistor, am I in the right ballpark? It's my first time working on an amp, any help or direction would be appreciated.

update: I tested all the transistors and got consistent readings on all of them (I think)

service manual: Table Of Contents - Denon AVR-1913 Service Manual [Page 2] | ManualsLib

Hi,

I plan to build a passive summing mixer with 8 inputs and 2 outputs.
I follow this diagram :

All inputs resistors are 6.8k ohms

To calculate the summing resistor I use the New York Dave formula (I/N)*R/((I/N)-R, where I is the input impedance, R the desired output impedance, and N the number of channels.
So, here, the summing resistor is 165 ohms

How to calculate the output summing resistors needed if I want to add a second output to this diagram ? Each output need to be at 150 ohm for the mic pre amp that after.



Thanks

Hi All!

I picked up a near mint condition Music Hall Mambo integrated amplifier from an acquaintance's mother. She used it but sparingly, which is evident by how clean it is. I got it for a reasonably good deal-- $550.

This is a 50lb Class A integrated. It's really nicely made, but I'm fooling with the idea of making it into an upgrade/modification project. I know that Underwood HiFi and maybe Parts Connexion were offering modifications that cost near $1,600. See Mambo | Underwood HiFi.

I popped it open today to poke around. Here are some photos.





Any advice on where to make modifications?

I was thinking of figuring out the following:

Swap two caps on gain signal --or at least what I think is the signal
Change electrolytic caps from Elna to Mundorf M-Lytics, etc.
Change out the Burr Brown 2604AP OP Amps (x 5)

Any help would be greatly appreciated!

For the money this little DAC cost I think its one of if not the best $250 I have ever spent on a piece of stereo equipment. My only complaint was the range of the Bluetooth left something to be desired. It would cut out 15 feet away with good line of sight. BUMMER....
Well as it turns out there is a simple fix for this that I find hard to believe the factory didn't build it this way.
If you unscrew the BT antennae and look at the Brass elbow there is a setscrew like thing. Its actually a very thin cover that when opened reveals the solder connection for the antennae. An electrical radio friend of mine told me the optimum length for a BT antennae is 31mm based on the wavelength and the length it needs to be to resonate, thus making the most of the available signal. This one as it turns out is significantly shorter than that.
The fix is to slip the black plastic cover off the elbow revealing the existing antennae. Remove the elbow cover with a screwdriver and desolder the existing wire. Next measure out your new one FROM THE ELBOW WHERE THE WIRE BECOMES EXPOSED AND IS NO LONGER SHIELDED BY THE METAL. Y our total length of the wire will be a little longer than 31mm. Like 38-40 or so.
Cut it, solder it on and be sure to slip a piece of heatshrink over the wire so the wire and solder joint inside the elbow will not touch the elbow. Verfiy your 31mm length and put the black plastic cover back on.
And enjoy your SIGNIFICANTLY improved BT connection. Mine is a hell of alot better. I haven't measured it but it works great everywhere inside my house. Compared to previously its a huge improvement.
*I can not vouch that the 31mm length is indeed the optimum length but my friend is a pretty smart dude and mine worked great.

Enjoy.

Jeff

Power Supply for Class-D amplifier module

I've built several small (~500mA) dual rail power supplies; mostly 12-15V stuff for a pair of opamps each. These have been very simple designs since the current is very low.

However, I'm looking at my first "serious" dual rail linear PSU, something to power one Class-D amp. The module I'm currently considering is the ICEpower 500A, a 500W (@4Ohms) amplifier module. It requires a dual-rail power supply between 45V and 80V, with 75V being "recommended".

With the smaller power supplies it was easy to get started, but this seems like something else. I'm hoping for a few resources / pointers in the right direction as to where I can find information on building something like this. Perhaps I've missed it, but I couldn't really find very much!

Phill

please delete

So, everyone knows the equal-loudness curves, which show the sound pressure (in dB SPL) needed to achieve a particular loudness in phons through different frequencies.

This curve is fundamental for many areas of acoustics and hearing, however, I wanted to bring more information out of it.

Firstly, they don't show the variation in loudness of sounds with a same sound pressure through different frequencies. That is very important, specially if you want to understand how a "flat response" should sound like when you feed it with pure tones of the same amplitude.

Secondly, the unit phon itself isn't the closest to be linear with perceived loudness. The unit sone was made for that, but needs corrections for very loud and very quiet sound (and it's a bit of an approximation anyway, loudness is very subjective, but this is still better for a psychophysical approach than phon).

So, I took the data from ISO 226, converting the values from phons to sones and the values from db SPL to Pa (pascals) to find a loudness curve for each frequency, relating the perceived loudness with sound pressure.

For example, for the 100 Hz frequency, the data is:

I then performed a fitting to find the values for other sound pressures. The model I used is a simple power-law expression:

L = A·p^γ

Where L is the loudness, A is a constant, p is the sound pressure and γ the exponent (a dimensionless constant)

Not only this model provided a near-perfect fit (R² > 0.999 always), it is also the same used for gamma correction, and the value of γ (gamma) tells a lot about dynamics.

If γ = 1 for a given frequency, then the perceived loudness is directly proportional to the sound pressure. Which only happens in one frequency, around 60 Hz.

If γ < 1, then the perceived loudness is compressed, meaning that doubling the sound pressure doesn't double the perceived loudness. Everything above 60 Hz is compressed, and the most compressed frequencies are exactly those we are most sensitive to, between 2 and 6 kHz.

If γ > 1, which is the case for everything below 60 Hz, then the perceived loudness is expanded, so doubling the sound pressure more-than-doubles the perceived loudness.

The constant A is a different one for each frequency, and also has a different dimension for each. Its unit has to be sone·Pa^-γ, so it's only the same dimension if γ is the same. Nevertheless, it's still useful to compare their values, for they tell a lot about how each frequency is "intrinsically loud".

Here's a graph of how the A constants and γ values vary with frequency

The graph on the left will give the overall shape of the equal-pressure loudness contours. The graph on the right tells about the dynamics of each frequency and how the contours will change with different sound pressures.

So, using these data, it's possible to make the contours I wished for.

Here they are:

Each curve in the graph on the left shows the variation in perceived loudness for pure tones of different frequencies with the same sound pressure.

The curves on the graph on the right has been normalized so the loudest frequency of each curve has a value 1, and it helps visualizing how the proportions between the loudness of each frequency changes with sound pressure (due to their different dynamics).

In the curve for 20 mPa (the cyan curve), the frequencies around 15 kHz are just about 40% as loud as the frequencies around 3 kHz (the loudest in all cases). But, for 2 Pa (black curve), they're 80% as loud as 3 kHz. Their loudness relative to 3 kHz double.

The bass frequencies change even more. In this same range (from 20 mPa to 2 Pa), frequencies around 40 Hz go from being 1% as loud as 3 kHz to 10%.

The frequencies between 2 and 6 kHz keep their proportional loudness because their γ are nearly the same, around 0.585 (they have the same dynamics).

Although the data may be imprecise, this is just an approximation when it comes to your actual loudness perception. But in a way or the other, this is still useful for a ton of qualitative observations.

The main observation being that, no mater how an equipment is good at keeping its profile (flat or whatever other it has), the equalization will sound different at different SPL, increasing the overall loudness will also increase the bass and mid-bass (from 20 to 600 Hz) and treble (12-17 kHz) relative to mid-highs(2-6 kHz).

These contours also help "equalizing by ear", as they give a notion of how it should sound, taking the loudness of 3 kHz as a reference. The only thing you need to know then it's the sound pressure level you're dealing with.

For a reference, here's a little table I took from wikipedia:

Hi Guys,
Just managed to pick up:
LINTRON Toroidal Mains Transformer 15V @ 30VA



Is this going to sufficient for driving a single LM3886?

I found a formula on the Lansing Heritage site, derived by Frank Massa working for RCA at the time in the 1930's for calculating excursion of a compression driver.



I don't however know if the 'area' of the diaphragm is taken as a flat piston or considering the area of the dome. Anyone know which is correct? I am assuming that it is considered a flat disc when calculating the area.



"P = .0034 X f squared X d squared X Ap squared, all the foregoing divided by Ah"

Where:

Ap = diaphragm area in square inches
Ah = throat area in square inches
f = frequency in Hz.
d = peak diaphragm amplitude in inches
P = power output in acoustical watts


Assuming a 3" diaphragm compression driver diaphragm at 800 hz, given 0.060" to the phase plug ( I haven't measured that yet ) and a throat of 1/10th the 3" diaphragm ( 10:1 compression ) I get in the neighborhood of 78 acoustical watts at the point where the diaphragm hits the phase plug.



P = 0.0034 x 640,000 x 0.0036 x 49.96487 divided by 4.99648 = 78.33 Acoustic watts


The formula explicitly states that the area of the slots in the phase plug is considered the throat for the calculation of throat area.



If we say 75 peak acoustical watts, that works out to 138.75 dB sound power level at the phase plug exit. Coupled to a horn with a directivity Q of 10, and measured at a distance of 3 meters, this calculator: Sound power level SWL and sound pressure level SPL distance compare acoustic power sound source noise Conversion of sound pressure to sound intensity conversion sound level energy level strength directivity factor coefficient sound intensity SIL - se


The result of plugging in the above numbers says 128.21 dB pressure level at 3 meters distance.



Am I way off base, or does this seem correct? The driver in question has a 3" diaphragm and a 1.4" exit.

Hi everyone,

I want to run an idea past you guys regarding building a 2.1 cinema system
On a 30ft houseboat frequency response down to 16hz.

What i propose is building tanband horn speakers from plans with
A 4"tanband full range driver, a pair of these will be the front speakers
These are bookshelf speaker sized and would be constructed
Using stacked plywood.

The bass speakers, i want to use an infinite baffle as i have read
That its capable of super low frequency bass and is used by
Electronic organ players to get the 16hz fundamental they do this
by fitting a pair of 12" bass drivers in the ceiling and using the loft as the infinite
Baffle, i propose using the floor and bilge as the baffle as its
30ftx9ft and 3ft deep, the floor is made from 20mm marine ply
And is braced every 4ft as the structure of the boat, the hull is
Sea going and extremely thick fibreglass.

Would this work to form an infinite baffle and also do the tanband
Horn plans produce a good sounding speaker?

Thanks, Mat.

All ready to give away a very sweet sounding amp and speaker system to my sister and brother in law when I discovered one channel on one of the three sources not working at all.

Three pairs of RCA input each pair connected to a relay - I managed to desolder the 10 pin relay and replace it with a socket and a new relay but still no joy on the same input source. Relays are triggered by three way toggle switch on the front of the amp. Relays are TQ2 5V DPDT Type Form C

https://b2b-api.panasonic.eu/file_stream/pids/fileversion/4514

Output from the circuit board is the same pair of cables sharing a ground connection and L and R for all three relays. There's a couple of resistors and transistor on each relay - I don't understand why I only get one channel if the relay is working.

Any Ideas very welcome Pictures from Ali Express site with source relay board in the middle.

I believe this is the end of almost what trying to aim at?

And if i folded that 240 cm at 120cm+120cm i would fill in the response and because it would be the harmonic of 120cm which is 214hz to its own and 107 is the Fb /3. i probably have misspoken and theres a variety of ideas and options here including other intervals of 240 or compounded approaches. Paraflex is a good one, roar is great, ODTL is outstanding!!! And ODOE TL is the cats meeow, but the tip of the iceberg for a taped driver might be placing it in the middle of two qw paths which themselves are split at midpoint? Or a mathematical version of pipe harmonics and open ended pipe harmonics, etc?

B@se wave cannon, etc... lots to read and lots of ideas!! Heres half of nothing but close to a unsimmed(wont fit into the programs assigned fuctions) guess? 240 cm @ 120/120 seals the deal? Or ? Its only 30’degrees closer in a compound? Vs standard Qw pipe at 90. And however method we can use to describe the phase at various layouts ‘offset’?

I would like to be able to cut lacquers from a DSD source with lathe automation. This requires four channels. Two channels feed the automation and the other two channels feed the cutterhead. The Modulation signal that feeds the cutterhead needs to be delayed by either 1200ms or 800ms depending on the record speed.

For PCM I just take four channels from my DAW. I don't have a multichannel DSD workstation. There are plenty of two channel DSD playback devices.

Mini DSP sells the MCH Streamer which can stream eight channels of DSD. I asked MiniDSP and they said there wasn't enough memory to delay the stream.

What could be used to delay the DSD stream to give me the Modulation signal?

Hello, I owned a Threshold S/300 for several years then sold it about a

year ago.

I drove a pair of Acoustat model 2+2's with it. I am now considering between

a used Pass Labs X150 and a Threshold S/350E. The S/350E was

upgraded by John Soderberg. Both used pieces go for about the same

price and both are rated 150wpc into 8 ohms. I liked the rich, warm

sound quality of the S/300 with my Acoustats.

Which of the 2 amps would be the better

choice as far as rich, warm sound?

Selling a pair scanspeak d2905/9900 in good condition, dome has some cosmetic.
Asking $200 shipped, US shipping only.

Would like to use some arrow tips I have, and was trying to think of a "well" or tip reciever, and thought, has anyone ever used a speaker spike/inverted cone? Found ones from dyna, 5/8" diameter and about 1 1/2" long. Any other thoughts are appreciated! Learning before building......

I realize this may be a stupid question but.... I am considering going to DC heaters on a preamp. The original design elevated the AC heater voltage 60V. How does one accomplish the same thing if using DC? One cant just float the 6.3VDC on the 60VDC of the original design can you?
Thanks in advance.

I have an HK990 that functions properly but the right channel runs 10 degrees F hotter than the left when measured at the heat sinks. Is this enough to be concerned about? (I'm a novice at circuit level electronics, so it's something I don't feel qualified to chase down and repair if it is.)

Also, if anyone knows of a good technician within 75 miles or so of Lansng, MI that would be good at servicing this unit, I would appreciate the referral. (Blackies in Grand Rapids, MI is the closest authorized HK service center, but I wasn't overly impressed with them.)

Thanks for your thoughts.

Happy New Year to all of the Pass Labs followers out there! It's nice to have a refuge where we can distract ourselves during difficult times.

I hope things settle down and return to a sense of normalcy in 2021. Until they do, stay healthy my friends!

Hi friends

I'll build a ladder attenuator with 25K Load resistance.
The calculator I used (attached) shows a few resistors are repeated (say, position 8a - 4a, 3a - 1a etc.)
I have to solder every single one into its position because they're going into a different b-position, is that correct? or would they pass through the respective a-position at the value, and through the next deck into the correct respective value?

scratching my head...

I’ve built this Aikido Cascade using a 6SN7 from Aikido Cascade & 300B Power Boosted. It’s in use as a input gain stage before my phase inverter.

It measures quite well as far as distortion and amplification is concerned. I cannot find much information about this diagram, so it’s hard to check any of my measurements with it’s design parameters.

I wonder what would be the input and output impedance for instance. For which input level would it be designed? What would be the optimum value for a volume control at the input?

I think I already get full drive with only 0.7 V Peak to Peak, so what would be a good way to lower the amplification without losing the Aikido design philosophy?

Regards, Gerrit

Quick question: Does the primary impedance of an OPT scale linearly as load on the secondary changes?

In other words: If I connect 8ohm speakers to my 8ohm tap, the primary OPT impedance is 5k - so if I connect 4ohm speakers to my 8ohm tap the primary OPT impedance will drop to 2.5k (4/8=0.5*5000=2500)?

Doing the math for a different scenario:12ohm speakers on the 16ohm taps will result in 75% (12/16=0.75) of 5k = 3750 ohm primary impedance?

Same thing for 3ohm speakers on 4ohm tap?: 3/4=0.75 * 5000 = 3750 ohm primary impedance?

I was wondering if anyone could tell my why my PS would drop voltage with it only pulling about 5-10 amps. I have replaced all the "pass transistors"? (TO-3)

no text

Got a Onkyo TX-NR807 MDC with a bad HDMI board. There was a known issue with the soldering on the DTS chip and the factory extended the warranty for quite a while. Unfortunately, that extended warranty is past. The owner had asked me to see what I could do with it, and I was able to reflow that 320 pad BGA with a heat gun, and the repair lasted about 3 months. Started failing again, and additional attempted repair has been futile.

So I am looking for a used, functional HDMI board. The manual calls it
BAHDM-0132-1B, the actual label on the board is BCHDM-0132.

Anyone have any leads on where I might find a good one (for a reasonable price)?

Looking for a nanoSHARC

To sell almost as new, because I did soldered it to a Preamp, a top quality TKD 2C-2511 stereo log 20K motorized pot + Hifi-Collective Glass House control board + IR remote control.

Selling, because the decision went into another direction.

Price is 150€ + transport + 3% PayPal fee.

All box thoroughly.

Super quality pot!

Paid for it one week ago +200€

Thanks for looking

I ordered all the parts to build another one of these preamps but the boards went out of stock. Looking to buy one for what you paid in full from diyaudio. Willing to cover the extra ship if needed to Houston, TX.

Looking for a pair of Magnequest plate chokes to hear how a complete magnequest parafeed setup will sound like. Thanks.

Ok so I'm new to all this , but learning

I have a 3 way speaker , that I need to work out a Xover for it

The midrange is a 5.25" dynaudio driver

I measured 5.3ohms DC resistance ( both measured identically )

Does this mean the drive unit has a 8ohm impedance?

Or maybe 6ohm ?

No idea if dynaudio make 6ohm drivers ...but a reading of 5.3ohms DC seems low for a 8ohm driver ?

Any info greatly appreciated

Hello Folks,

I've put a bunch of effort into designing a workload of small PCBs on a 100x100mm board. Some of the small boards contain SMD and THT components, the individual boards are separated by v-scores to easily separate them after manufacturing. I have seen such board workloads in the LT4320 thread, so technically that should work and so far the theory...

A few moments ago I chatted with JLCPCB to verify the right way of ordering my workload. It turns out that JLCPCB cannot (anymore?) produce v-scored PCB workloads containing THT and SMD component layouts.

I'm not experienced in PCB manufacture, this is my first project, so who ever can help, please advise!

Thanks and Regards,
Winfried

Working on old PL3000 pre with switching issues. Powers up defaulting to Tuner input correctly. When I switch to another high level input it will switch LED to new in put but the tuner LED stays on also. Doesn't do this every time but at random. See that the relays are no longer available. Uses relay that matches 16pin DIP footprint. Looking for same footprint that matches on small signal relay. Not finding. Service manual talks about a relay regulator circuit but can't find info on that. HELP!

Hi,
I am looking for 2 pairs of EDCOR PC600-15k transformers with European sourcing.

Don-Audio indicates a purchase period of 2 months.

Does anyone know a faster solution?
THX!

Dee

Given the scarcity and high prices of new old stock SJEP120R100 transistors, I have been wondering if they could be salvaged some from other equipment.

Based on the following excerpt from a 2009 press release, it looks like they were originally intended for other more industrial uses:

"SemiSouth believes this is the first SiC transistor to enter production in the audio amplifier market. The JFET has traditionally been featured in rapidly growing markets for solar inverters, and server and telecom power supplies, among others."

Link to Press Release

Its a long shot, but does anyone know of specific equipment likely to have used these that might be available as scrap or obsolete?

Does anyone happen to have a pair of Sowter 1:1 input transformers (10K or greater) on 3/8" threaded bushings that they would sell?

I have this idea of using an input transformer as a phase-splitter in a PP 6B4G/2a3. So I would like to know if there are any relatively low mu triodes that could go between the input transformer and the output tubes. For reasons too embarassing to go into my input transformer has to be used at 1:4 or 1:8. Any suggestions would be greatly appreciated🙂

For Sale: Alpair 7 –Grey-R3

Third generation Alpair 7 in grey color. Never used new in the box. I have 4 of them.

Will ship double boxed. $290 + 10 shipping for $300.00 Paypal works best.

Hi all,

I have a problem with my Rotel RA-930BX. It simply is totally off!

Fuses are ok, I measured the AC in the board and it is ok also.

Maybe it's an easy thing, but I can't find where's the problem!

Just stopped listening to the music! 🙁

Any help will be much appreciated.😱

I wanted to keep hold of this but now 3e do a mono amp and I have a subwoofer project, I am going to give the 3e board a go due to smaller footprint.

£60

Don't have the original box but shall provide a sturdy bix and package well.

Hello,
I am in the process of building a pair of Woden Bloodhound speakers for my PC and I would need help figuring out how to choose an amplifier and DAC to drive them. These speakers use MarkAudio Alpair5.2 drivers.

I know this is a diy audio forum but electronics is a bit out of my capacities I think 😱
How do I make sure I am not over/underpowering my new speakers?
Does anyone have recommendations on what to choose?
I don't need anything fancy, only stereo, no bluetooth, etc.
Thanks!

Hi all,

I have the parts to beuid an F6, sans toroid. But the standard 4U enclosure will not meet with my wife's decorating approval. The amp will go in the living room and there is no place to put it without it looking obtrusive.

I have plenty of places I can put a 2U high unit out of sight and still provide for good ventilation.

So, I was thinking to make two 2U monoblocks but with the output MOSFETs connected to their own heat sinks on each side of the chassis. It will look like a lower profile steroo amp but actually be a monoblock.

Questions: What are the issues in doing this? I'd have to run wires to the SD and G pins from the board to each MOSFET on each side. Probably 4~6 inches for each run. Will this be a problem?
Any suggestions?
Has anyone tried ths?

Many thanks for your help.

Hi everyone, and happy newyear

Sorry if this has been discussed before, could not find anything on it.

I have very much enjoyed dado's 200W CFA thread and downloaded the .asc file from post #1582 assuming it is the newest.
I did not have the IRFP240Ckst/IRFP240Ckst models handy, so instead I used the following models from Ian Hegglun.

*VDMOS with subthreshold (c) Ian Hegglun
.model IRFP240h VDMOS (Rg=17 Vto=4.0 Kp=6 Lambda=3m
+ Rs=40m Ksubthres=0.15 Mtriode=0.35 Rd=0.15
+ Bex=-2.3 Vtotc=-6m Tksubthres1=4m Trs1=3.5m Trd1=5m
+ Cgdmax=1.3n Cgdmin=10p a=0.35 Cgs=1.2n Cjo=1n
+ m=0.4 VJ=0.75 IS=10n N=1.5 Eg=1.1 Rb=10m Trb1=3m
+ Vds=200 Ron=0.15 Qg=45nC mfg=VishIH1907)

*VDMOS with subthreshold (c) Ian Hegglun
.model IRFP9240h VDMOS (pchan Rg=9 Vto=-3.76 Kp=9
+ Rs=64m Ksubthres=0.15 Mtriode=0.2 Rd=0.25 Lambda=4m
+ Bex=-2.3 Vtotc=+6m Tksubthres1=4m Trs1=3.5m Trd1=5m
+ Cgdmax=1.6n Cgdmin=30p a=0.5 Cgs=1.4n Cjo=1n
+ m=0.4 Vj=0.75 N=7 Is=10u Eg=3.15 Rb=50m Trb1=0
+ Vds=-200 Ron=0.5 Qg=44nC mfg=VishIH1907)

I then ran the bode plot as is, without changing anything else. It gave strange results, with a phasemargin of only ~39°.
Went backwards in the thread and found dado's latest zip file with schematic and models. It sims fine with expected results.
Then I changed the schematic from dado's zipfile to use Ian Hegglun's models, and I get the above strange behavior.
My impression was that the models from Hegglun and Cordell are all good, but they clearly behave differently.

Is there a consensus on which models to use for IRFP 240/9240 ?

Regards
Jørgen

I’m new to this so please go easy on me...I have a Boston acoustics sub woofer with an rca jack that I need to replace. Was able to get the old jack off the board but I can’t seem to get the old solder out of the 4 holes so I can install a new one.

I’m looking to recap my old hailer amp and get into some diy audio a bit and figured this was an easy starting point. I got a hakko soldering iron, tried 750 and 850, different tips, lots of flux, suction and wick. It’s like the solder in the board won’t melt at all. I tinned my tip and all that. Not sure this picture helps but I must be doing some newbie mistake...

Hi,


I've recently got a logitech s220 2.1 speaker system and it works but it has a very low bass.
I've checked the speaker with a multimeter continuity test and it works as it should.

The system has a main volume button and the bass has it's own too both seems to be working but the bass only audible when both is turned to maximum. The satellite speakers are working loud and clear.


I've checked the capacitors and they seem fine visually. I don't have a capacitor meter and haven't taken them out from the board yet.


So my question is that what could be wrong? Am I right suspecting the capacitors or there could be something else too?


Thanks!

Hi , does anyone know what type of transistor this is?
See attached fotos.

Hi!

I am trying to build a mono amp based on bridged TDA2030 (2050) with output transistors TIP35/TIP36. I found a schematic that seems ok here https://320volt.com/wp-content/uploads/2009/03/200watt-anfi-devre-semasi.png and I copied it in EasyEDA to build a PCB. But I am not sure if I've done it correctly, particulary the transistors connections.

Here is my schematic:


and here is an autorouted PCB I want to use as a reference:


BUT with a similar schematic (I don't have the link, but is quite similar, without any input filterning and decoupling), the PCB looks entirely different, regarding the connections of the transistors (BDA249/TIP35C and BDA250/TIP36C):


I used schematics/footprints contributed by other users for TDA2030 and TIP35C/TIP36C and I din't change anything in pins/footprints.

Is my procedure that wrong?

TDA2030 schematic and footprint:


TIP35C schematic and footprint:


TIP36C schematic and footprint:

Hi, I've been playing around with the DEQX for about a year now and
I've tried many speakers and combinations of measurements/corrections.



While I'm not completely thrilled with the DAC capabilities of the Hd Express II
I think that the room correction capabilities cannot be ignored.



So I wanted to share something I tried that I think sounds really good and also ask a question about it.


The usual method to correct the drivers (in this case Kef LS50's) with open baffle 15" woofers below)
is to measure each driver from up close and then correct and only then do eq corrections on the room.


Well I decided to try something different this time and I was pleasantly surprised. 🙂


I wired BOTH speakers (highs/lows separately) to the same amps so that both speakers
were playing in mono. Then I did my measurements from the listening position and then cut and pasted
the one side side to the the other so that both speakers are using the same FIR filter. I then separated

the drivers so they each get their own amp. And then I took the average response on both speakers playing simultaneously
and applied EQ.




And well it does sound really good. Im wondering if tehre's any explanation for this? Only thing I could think of is that using the same filter sort of 'averages' out the response in the room better.


Anyways there it is, hopefully someone more knowledgable can chime in on whether this is a good idea or a bad one.

I'm looking to build my own power distribution box. And hoping that someone out there can help with a few points.

I'm getting a dedicated 20A circuit installed in my house later this month. And a whole house surge protector. So I'm looking to build a unit without surge protection or power conditioning. Just clean and simple power distribution.

I'd like to build a 10-outlet box using five Hubbell HBL5362 duplex receptacles. One of them will be un-switched, or possibly have a separate switch. For connecting to the wall outlet (also HBL5362), I plan to use a 12AWG shielded cable. I'm a bit of a novice when it comes to things like this, but my trusted audio tech has agreed to mentor me on this one.

So here are a few questions:

1) What's the optimal type of enclosure and material? Seems many go with machined aluminum.
2) Does anyone sell "blanks" for power distribution boxes?
3) How important is a ground terminal? Many (usually higher end boxes) have them. Many don't.
4) Better to somehow solder the power cable in directly or use an IEC socket?
5) Should I install a circuit breaker in the box?
6) I'm assuming each duplex should be wired directly to the IEC socket rather than wired in series.

I think those are my main questions. But I'm happy to take unsolicited advice too. I don't want to show up to my tech knowing nothing...(!)

Hello,
I have a room which is approximately 7x4m, where I watch TV, listen music on my couch which is on one half of the room, or listen music in background while working at my table which is on the other half. In all three cases I'm facing the long side of the room, but pointing towards different points.

I was thinking to place 3 speakers on the long wall so I would use the left and middle one as left/right when listening on the couch, middle and right when listening on the table, and left and right (maybe with some contribution from the middle one) when watching TV.

I also would like to build myself the speakers as two ways using an active crossover. I could use DCX2496 as active crossover and room compensation using three setups for the different listening points.

What do you think about it? Is it a good or a terrible idea?

ES9023,just unmonted it from the case.
It comes with the original PSU and the JG Buffer.
All that is neded is a PSU for the buffer.
150 Euro or 180$ + shipping.

Allo USBridge Signature for sale with Shanti Power Supply. Bought from a head-fi user earlier this year. Going a different direction. Good condition kept in a clean smoke-free room.

Looking for $325 shipped and insured in the USA

PM for pics. Thanks for reading!

Hello, I am repairing 401m. I've had it for a while (Years) and have just gotten back around to it. This one is a weird one and I'm at a loss. I am thinking that the main IC (IC2) may be faulty.

Checked the power supply and output transistors and all check out fine.

I removed Q20 and Q21 because I couldn't get the amp out of protect. Verified that there was not 5v going to pin5 but the amp is still in protect.

Applied 12v to the pwm IC and the power supply powers up fine. Verified a nice solid +/- 62v and 15v rail. Amp pulls a low 2 -3 amps at idle.

Everything outside of IC2 seems to be functional. It just thinks something is wrong for one reason or another. I'm almost tempted to short the emitter and collector on Q22 to get the relay to turn on to see if I can get audio out of it.

Any suggestions are greatly appreciated and thanks for you help~

I’m going to build a sealed enclosure with a single full range driver in it for a desktop nearfield audio mixing monitor. An incidental bonus would be a driver that has a ported enclosure size that’s close enough to allow experimenting in the same enclosure but this is not necessary. I’m good at woodworking. I prefer paper and if not then poly. I have been looking at some of the usual suspects: tang band, foster, Mark audio, Dayton audio, visition, etc. after 40 years of rock guitar my hearing is shot above 10k so that doesn’t matter much in this case although some of these speakers have pretty impressive upper extension.

What choices have worked out well for you guys and given the best results?

Thanks,

George

So, I'm starting a project along the lines of a Helium -- just a little tyke (6.5" high, 4.5" W, but 6" D), and rather than the ND16FA-6, was wanting to use the ND25HF-4. It looks a lot smoother and flatter, and it should let me push the X-over frequency down (which I think I want to do), and if I'm not mistaken I think it is a step up from the ND16. I built a pair of overnight sensations, and I think the ND20FA-6 sounded pretty decent. Maybe they aren't that different (same family)?


Here's the problem:


Tweeter be big -- box be small!


Dayton Audio ND25FA-4 1" Soft Dome Neodymium Tweeter




There are a couple of options here:
1) buy the version without the face-plate and figure out how to mount it


Dayton Audio ND25FN-4 1" Silk Dome Neodymium Tweeter Element 4 Ohm


2) modify the face-plate into a square 2 1/16", which looks doable I could do that, but it looks like it might make the face-plate a bit flimsy, but I could reinforce that if necessary


Has anyone done either of those two things? Or, does anyone know if there are options for changing the face-plate. It's not clear whether the voice coils can be replaced, or whether the tweeters can be disassembled (which would make modifying the tweeter a bit easier).


Thoughts?


Other tweeters to consider:


HiVi TN25 Fabric Dome Tweeter (small rectangular flange that would work)



Tang Band 25-1166SJ 1" Neodymium Soft Dome Tweeter (flange could be modified)


Peerless by Tymphany D26NC56-06 1" Fabric Dome Tweeter 6 Ohm (might work as-is, or could modify)

Hi looking to install a cheap speaker like Timpano
TPT-MD8 8 ohm in place of the stock speaker. Do I need to adjust the cross over cap etc...no help from manufacturer

• Nominal Diameter8"
• Power Handling (RMS)130 Watts
• Power Handling (max)260 Watts
• Impedance8 ohms
• Frequency Response80 to 9,500 Hz
• Sensitivity95 dB 1W/1m
• Voice Coil Diameter1.5"

Thiele-Small Parameters

• Resonant Frequency (Fs)72.6 Hz
• DC Resistance (Re)5.8 ohms
• Mechanical Q (Qms)19.3
• Electromagnetic Q (Qes)0.69
• Total Q (Qts)0.66

Hi,

First post on the forum, and seeking a bit of advice. 🙂

As a first attempt at building a valve amplifier, with an aim of learning more about valves in general, I've built a version of Pointdexter's Audio Tropic 6v6 musical machine.

It's up and running, adjusted as per the design, and various threads from back in the day. Sounds nice, and I'm quite happy with it. Doesn't hum, hasn't caught fire, arced over or anything else amusing. 😀

I've just been doing a few measurements to see what it's actually turned out like; I've no more fancy test equipment than a cheap multimeter, Hantek USB scope, and REW.

I should add that I aimed to build this as cheap as possible, primarily because I wasn't entirely sure I'd get it to work. So it's a lab experiment rather than aimed for perfection like some of the lovely builds on the forum.

I designed the board trying to keep the input audio route straight and the heaters away from the input side as far as possible. Laser transfer and etched at home effort. 😉

I redesigned the PSU to take advantage of the most cost-effective transformers I could get hold of shipped to/in the UK in a sensible timeframe. More relevantly I'm also running extremely cheap 100v line transformers as OPTs. This was inspired by http://home.alphalink.com.au/~cambie/6AN8amp/M1115.htm ... 😀

I've attached Poinz' schematic here (again), along with my schematic, a few photos and some measurements.

The issue I'm seeing is that I can drive the amplifier into clipping at 1khz just beyond a measured output power of 2.5w, which seems on the early side.

I'm assuming the bass rolloff I'm seeing is from the tiny OPTs. The -3db point at 1W is around 44hz, and at full power, more like 56hz. I'm okay with that, so long as it's the OPT causing it. Limitations are fine! 🙂

It makes about 5.5w into 8ohm, at 1khz flat out. That's for a 2v measured p2p input. Haven't tried driving it harder, as it's already firmly clipping at that point.

Basically wondering if what I'm seeing power/clipping wise is about right?

Cheers! Paul

This seems fairly basic/fundamental, but I cannot find a definition
of "push-push" for two drivers. I read what seems like mis-used or
perhaps contradictory or unclear usage of this term.

Does "push-push" strictly refer to two drivers mounted with opposite
direction of cone motion, without ANY mention of:
1.) wiring polarity
2.) shared air volume
3.) firing direction (although I presume it means "facing opposite directions")
4.) Isobaric or not

So what is the definition ?

Does it ONLY refer to force-cancellation for purposes of controlling

cabinet vibration ?

Hi Guys,

I had wanted to do it a long time ago but.....anyaway I'm finally on vacation and I have a litte bit time to put in place some modifications, substitutions and calibrations on my old active loudspeakers Audio Pro A4-14 Mk2 that I have bought more or less........thirty years ago. 🙂

I have replaced the suspension rings of the woofers, Sipe "AS.130 42148" with new foam rings, I have replaced the two old electrolitics capacitors on the DC power line with two electrolitics on high capacity to improve the current request on transient, I will clean the potentiometers and the switches with a specific spray, I will substitute the critical tantalium capacitance on the signal line.
After these activities I will calibrate again the bias of both power amplifiers and the ACE Bass circuit like indicated on the Service Manual.

Below the first one photo concerning the capacitors substitution on PA circuit, more photos will follow.

Kind regards
franco🙂

Can i change the surrounds of my woofers to softer ones?

Hello all. I have a pair of 12" woofers currently installed in a 3 way system. Some years ago they went for resoration due to surrounds and voice coils being in bad shape. The surrounds back then were accordian cloth and the speakers could easily go as low as 25hz in 40ltr sealed cabinets. After they were sent back to me, to my surprise i found out the surrounds were changed to some really rough and stiff type which was again accordian. It wasnt the normal cloth type they had before. I contacted the guy who overhauled them and he told me that they were the only suitable ones he could find and that the cabinets i have would no longer work with these woofers. So after sending in the speakers for T/S measurements, with his help i constructed a new pair of speaker boxes which are the current ones. They are vented, around 70-80ltrs volume for the woofer alone. The vent is 10cm in diameter and 3 cm in lenght. The woofers are -3db at 800 hz.

Bass response is very mellow, maybe a even a bit too much (comparing to their previous sealed enclosures where it was more tight and on the punchier side) but what i still cant get over after years of time is the fact that it cuts off at 50 hz. Which just bugs me out as these are big enclosures with big speakers in them. So my question is can i change the surrounds to a softer type without making a mess out of the bass response? T/S paremeters for the woofers are as follow:

Fs: 60 hz
Qms:3.32
Qes:0.60
Qts:0.51
Mms:35.86 g
Cms:0.19 mm/N
Vas:76.27 ltr
Bl: 10.22

Thanks in advance.

Just a quick one, what's the best stuffing to go from adiabatic to isothermal compression? It's for a second chamber of an aperiodic enclosure, so sound absorbing is of no importance. I just presume high specific heat, high density and high thermal conductivity would be desirable. Would copper wire ( screening from old coax? ) have any worthwhile advantage over polyester?

Dear all


I bought a DBX 234xs crossover which I need to interface with my hifi system.



The DBX xover is a professional device and I'd like to undestand what's the best way to connect it between my unbalanced preamp and power amp. I know that working with balanced/unbalanced devices can be tricky.


I plan to build my cables. I have RCA female connectors on both amp and preamp. The xover has female XLR input and male XLR output socket.


Can you suggest the best way to connect?


Pietro

Price will be:
250 Euro for Chassis + Handles + Internally mounted Steel Plate for mounting components
241 Euro for Chassis + Handles

For payment and ordering, follow link

Ricerca - 1HFTOXIC

You can't place an order till after January 1st, 2021.

If you're purchasing the Cardas Back Panel then you need to order these parts:

CARDAS PARTS SUPPLIED BY SONICRAFT

Binding posts

Cardas CCGR S Binding Post, Sonic Craft

RCAs SHORT VERSION

Cardas GRFA S RCA, Sonic Craft


RCAs LONG VERSION

Cardas GRFA L RCA, Sonic Craft

XLRs

Cardas CM F XLR Chassis XLR, Sonic Craft[/QUOTE][/QUOTE]

Alternatively you could use Neutrik XLR jacks.


Shorting Pins For XLR's - OPTIONAL

Cardas CGSP, Sonic Craft

If you want to use other RCAs and Binding Posts then choose the back panel with pilot holes.
The XLR cutout is compatible with either Neutrik or Cardas this is common on both back panels

Chassis Specs

10mm thick Aluminium Front Panel - Anodized Black or Silver

Dimensions
450mm wide
500mm deep
165mm tall

Heatsinks 500mm x 165mm

Heatsinks will be drilled and tapped to be compatible with all Firstwatt amps in the store (UMS spec) as well as some additional holes that use more of the heatsink real estate, as well as add the option to mount longer pcbs etc.
Back panel is predrilled and cut to accept:
Schurter IEC
Neutrik or Cardas XLR
Pilot hole to drill out to RCA size of your choice - it is suggested to use Cardas
Pilot holes to drill out to binding post size of your choice - it is suggested to use Cardas
Holes installed for handles.

4U x 500mm Toxic Masculinity Chassis

So far the list is:

Blk Dynamite x 2
Savu x 2
Mr Dewk x 2
Pico x 1 (maybe 2 if required to get to 25)
Gary S x 1 (maybe 3 if price is reduced further)
pwagner x 2 (maybe 3 if price is reduced further)
Hey Bill x 1 (maybe 2 if required to get to 25)
Super_BQ x 1 (maybe 2 if required to get to 25)
Mirio x 1 (maybe 2 if required to get to 25)
Ozorfis x 1 (maybe 2 if required to get to 25)
TungstenAudio x 1 (maybe 2 if required to get to 25)
ItsAllInMyHead x 1 (maybe 2 if required to get to 25)
Gnub x 1
Subbu k x 1
hifibluedevil x 1
BrianGasberg x 1
Gerald1951 x1
Cakyol x 1
vvs07 x 1
6L6 x 1
Theodosis O. x 1
Dennis Hui x 1
Kasey197 x 1
Sampsonite x 1
Argos x 1
wg45 x 1
dantwomey x 1
32y0 x 1
Kbergsson x 1
Analogdiy x 1
ggetzoff x 1

Hello,

Just got a FCS-926 Equaliser, I've been looking for one for some time, it has analogue filters which are digitally controlled..
Info about the unit here: FCS-926 | BSS Networked Audio Systems

Unit arrived with multiple marks and was quite dirty so I thought I'd clean it quickly before installing it.
As soon as I opened it I noticed these awful modifications as if someone 'serviced' it with a kitchen knife, it's absolutely butchered.. 🙁

Can someone trace the changes and help me understand what has been done?

Back panel MIDI connectors:


Real Time Analyzer:






Front panel ribbon connector:


R92 disconnected:



Cheers!