They are in a plastic tube and have been since I bought them about 10 years ago from Digikey. Shipping would be from Germany.

I would like 100 euro for the lot with shipping on top.

I will post photos later.

Thanks

I'm into Audio of all sorts, and have to do most of the repairs myself as it's almost impossible to get any repairs done specially to vintage stuff. This site has valuable information.. Thank you

I'm wondering if there is someone out there that has a working amp circuit board for a realistic sta 2700.

I'm looking to build an Aleph Mini, currently trying to gather parts to order, for now I have found:

https://www.ebay.co.uk/itm/266392011176?mkevt=1&mkcid=1&mkrid=710-53481-19255-0 - the pcb
https://www.ebay.com/itm/156560013829 - mosfets
alternatively, but I'm not sure if it'd be quite right - https://www.ebay.com/itm/115126018088?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=wGG0QMocRHa

https://a.aliexpress.com/_EIU0SPC - enclosure

I'm just not quite sure about the PSU, what board / transformer should I use, and how to wire the potentiometer, switch.

Some sound clips of this speaker recorded with my phone and powered by my SuSyLu 100w Class A amp:

Test of SuSyLu 100W Class A Amp - YouTube

Example of speaker in dark “espresso brown” stain and satin lacquer with Duratex coated baffle.


Example of beautiful build by as8912:


Another Example of a floor standing FAST TL by Plott:

This is a great shot of the internals as provided by Plott:


Example of a floor standing TL version of this speaker by Moutik:


Example of a smaller sealed version with PS95-8 full range drivers by Jimk04, here.

I wanted a speaker design worthy of the exceptionally high performing ScanSpeak 10F/8424 Discovery 3.5in full range driver. I decided that a short sealed Dagger TL coupled with a sealed bass unit would give me the best overall transient response and clarity. I decided to mate the 10F/8424 with the superb Dayton RS225-8 aluminum cone woofer for bass duties. The design ended up as a 24 liter volume for the woofer and a 1.1 liter 3-sided pyramid Dagger for the 10F/8424. The important external dimensions are: 10.0in wide baffle, 7.5in CTC distance from woofer to fullrange, and 24 liter internal volume (sealed). You can make the height and depth to suit your individual case, but it will need to be deep enough to house the Dagger. The internal dimensions I settled on were 8in wide x 12in deep x 16in tall.

However, if you make it out of 18mm plywood like the ones I had my cabinet maker build - make the box using these dimensions.

Dimensions of sealed box version: most important is to make the width 10.0in (external) and CTC spacing between drivers 7.5in and adjust the depth and height so that you have about 24 liters volume. If you make it out of 18mm plywood it ends up about 18in H x 13.5in D. The 10F is located 4.5in top to center. You will need a rear chamber for tweeter (fullrange) so use a sports cone or wooded “Dagger” tall 4 to 5 sided pyramid. Stuff Dagger and main box with polyfill or fiberglass to taste.

New SketchUp Plans by @jrKC for sealed version here.



The short sealed TL is made of three 6in wide x 12.5in long triangles. Construction will use 1in thick pink XPS foam and regular foam core for the short TL. The front baffle will also use a thin sub-floor plywood in order to provide adequate support for the heavy 8in driver. The design will have the option of a bass reflex vent that can be sealed for use with a Linkwitz transform, or opened up for some additional bass when group delay is not an issue. The system will use miniDSP for XO and EQ duties and bi-amped. Here are predicted results in 4pi space with baffle step and diffraction effects accounted for. XO will be at 500Hz with 4th order LR. The RS225-8 is an exceptionally flat response driver and choosing a slightly higher XO frequency will keep the distortion on the 10F very low while giving more weight to the mid bass as it comes from an 8in woofer. Calculations show that with Linkwitz transform, bass extension should be about 42Hz (f3) with max SPL around 101dB.

SPL vs freq for sealed case at 24v (no Linkwitz transform) - the hump at 2.5kHz is the baffle diffraction:



Impulse response for sealed case:



Group delay for sealed case is 2.5ms at 100Hz and 5ms at 50Hz:



For bass reflex option, here is SPL vs freq at 24v:



Here is group delay for bass reflex (2.5in dia x 11in long vent - rear firing) case, not too bad actually (about 10ms at 50Hz)



Here is the Sureply thin baffle with driver holes and drivers to show basic look:



Here is construction on XPS enclosure beginning:



Here is the enclosure with Dagger TL internally mounted and bracing, wiring, and terminal cups installed:



Currently waiting for liquid nails glue to dry...

Edit April 27, 2015: New LR2 XO @350Hz and new sound clips of many different genres. Have a listen, this speaker sounds fantastic!

10F/8424 & RS225-8 FAST Ref Monitor - Page 2 - diyAudio

Here is the new LR2 XO @350Hz:


Update April 30, 2015: New Butterworth 1st order linear phase XO (BW1 XO):


Phase for BW1 XO:


Step Response for BW1 XO:


200Hz Square Wave with BW1 XO:



1.6kHz Square Wave with BW1 XO:



New sound clip with 1st order BW1 XO: http://www.diyaudio.com/forums/atta...or-10f-8424-rs225-8-fast-bw1-350hz-clip-b.asc

Edit May 14, 2015: Stereo Pair completed!



Edit Dec 16, 2015: forgot to post final lock-down configuration with Harsch XO:


IR:


Step response:

More info on final setup here: 10F/8424 & RS225-8 FAST Ref Monitor

Distortion:


Group delay about 5ms at 50Hz:


Edit Jan 5, 2018: using passive 1st order transient perfect XO for past 2 years.


Recent implementation with film caps and air core:


frequency response and phase using passive XO:


Impulse and step response:


Latest tweaks to the passive 1st order XO with simulation files:
10F/8424 & RS225-8 FAST Ref Monitor - Page 95 - diyAudio





Edit Dec 3, 2018: BOM for XO is here.

Edit: Dec 27, 2018 - Wxn just built a pair using SB23NRXS45-8 and TG9FD-4 with DSP from a DCX2496 here. The results look great and he did a great job on the cabinet:


Nice waterfall:


Edit: Dec. 27, 2018 - I should have mentioned that Aatto built a nice set using the SB23NRXS45-8 with 10F/8424 as well but using a bass reflex box and miniDSP and also with passive XO, but can't remember what he is currently using here:


Also, forgot to mention the nice set with RS225/10F that I built in espresso brown stain - these are working out real well as the WAF is excellent as evidenced by the fact that they are upstairs next to the TV 🙂 :


And of course, here is my current setup. These have been my main speakers for over 2 years now and, I keep coming back them because they sound so nice and balanced. The sharp percussion and wonderful stereo imaging also bring me back. Here they are in my speakerlab, now re-done post basement flooding (back in July 2018) with a new engineered wood flooring, so the echos are a mess and sound treatment is definitely needed now that carpet is missing. Looks nice and clean though - the clutter is building up again (mostly foam core speakers in storage around the corners).


Edit Dec 16, 2019: Thanks to JPS64 for making a super layout for the XO PCB. This will make building this speaker that much simpler.


Edit Dec 21, 2019: new TL floor stander for RS225:
10F/8424 & RS225-8 FAST / WAW Ref Monitor

Measurements of TL here.



Edit Dec 22, 2019: Just wanted to remind folks that there was a design made for this speaker XO with an RS100-8 and RS225-4 here:
10F/8424 & RS225-8 FAST / WAW Ref Monitor



Edit Mar. 20, 2020: Revised plans for the TL in all 3/4in BB plywood.


Photo of the TLs in action next to the sealed version:


Edit March 30, 2020: Vistaton B80 Variant with modified XO



Edit May 19, 2020: this is the XO for the 4ohm RS225-4. You can use your favorite 8ohm 3.5in full range on top. Just make sure it’s 8ohms and adjust R1 to taste.



Edit July 24, 2023: Keantoken developed a crossover specific to the TC9FD-8 to be used in this speaker with the RS225-8. The response looks very smooth and has a wonderful step response. More info here:

https://www.diyaudio.com/community/threads/10f-8424-rs225-8-fast-waw-ref-monitor.273524/page-196

Schematic:


Measured frequency response appears to have 1st order XO near 1500Hz.



Nice stuffing/padding plan collected by GUJoe:

In a joined effort, Bill, Dagfinn and I went into much detail by developing replacement diagrams for MM cartridges, divided into two parts, first the output section with coil, that we called the Generator, and second for the complete Cantilever assembly.
An achievement never realized before to the best of our knowledge.
Having developed the transfer functions for both both parts, we were able to prove that these two parts don't "see" each other, in other words, the external load on the Generator does not influence the Cantilever's movement in any way.
Another benefit by having the replacement diagrams, was that it was now possible to find the optimal load in LTSpice for a specific cartridge as regards to it's FR.
Because being too long to put it in a posting, we have added the results in the attachment as a PDF.

Happy reading,

P.S. A few typos haven been corrected and further explanation has been given to indentation.

I have been playing with WinISD and have decided to attempt to design a speaker with a slot port. This is what I have made in SolidWorks pretty quickly. The slot is 1in x 8in with a total length of 32in measured from the centerline of the port. I included rounded corners to hopefully lower air speed.. I am asking here if this is realistic and if this works. I found a woofer that I could use to tune the enclosure to 25 Hz.
These are supposed to be decent-sized speakers. The total dimensions of the enclosure is 27x13x9.5, this is a section view to show the port path.

I was following Ian Hegglun's thread "Towards a wideband non switching Auto Bias power amp",
and I was inspired by one of his ideas - Alexander-type input stage and VAS based on op-amp LT1223.

I wasn't familiar with this op-amp, as it seems too fast for typical power amplifier.
There is no point to use expensive ($10.00), high slew-rate op-amp, just to throttle it
later on in order to make the amp stable.

But, if it's driving VAS not from the output, but via rails (like Alexander amp),
the whole amp is more stable and less temperamental.
This amp here shows slew rate of well over 200 V/us, and it's a very simple schematic.

My past attempts show that it's very difficult to actually build stable amp that
can achieve slew rates over 150 V/us. This is first amp I see, that shows phase margin over 75, and
also decent gain margin. In the sim, it seems to be solid, well behaved amp.
So I think I'll give it a try.
First, I came up with LatFet version (dual-die Exicons ECW20N20 & ECW20P20) - that's the one I'm
going to build, and later on with HexFet version.
Both versions show similar results in LtSPice.
Noise floor (1kHz FFT) is at -280dB, and all harmonics are below -120db (inaudible).

Update 29 March 2025: Based on the actual build, C4 should be removed. With it, amp had tendencies to oscillate (when using LT1223).
I keep it in the schematic, purely for the simulation purposes. Apparently LTSpice sim is slightly disconnected from reality.
Also, gate resistors have been changed to R2: 220 Ohm and R3: 100 Ohm.

Update 30 March 2025: If using different op-amp, C4 should be present (2pF).
The following op-amps have been confirmed to work correctly (besides LT1223):
LT1357, TLE2071, TLE2081, AD711, OPA134, LF356. These op-amps were not simulated in LTSpice, just confirmed that they seem to work OK
in the real amp. The schematic and sim may not be optimal for these op-amps, so there might be some space for improvement
if using non-LT1223 op-amp.

Update April 2025: Actual amp has been built and finished. See Post #47.

Update April 2025: HexFet version has been built and tested. See Post #55.

Hi,

I'm trying to offload several DIY audio parts and even a pair of full speakers. I will charge actual shipping/insurance costs to your destination based on your preferred shipping arrangement (coming from Aurora CO 80016). Here are the items I have for sale:
Sold - $1000 - DIY Aleph J in 5U Chassis
$1000 - DIY Bookshelf Speakers with 15W/8530k-00 ($220/ea retail) + Seas Millennium ($482/ea retail) + Jantzen Crossover
Free - Pair of planar magnetic tweeters of unknown manufacturer - will ship with first person to buy > $100 worth of gear from me
$110 - Pair SB Acoustics SB17NAC35-4 (1 impedance measurements never mounted + 1 BNIB)
$180 for 4 or $100 for 2 New Peerless HDS 830875 Midwoofers (1 taken out of cardboard to look at but never mounted or measured)
$180 for 4 or $100 for 2 used Seas ER19RN-TRD mid woofers (These were in surround sound speakers for about 2 years)
$80 for pair of GRS PT6825-8 8" planar mid/tweeter (new)
$70 for pair of GRS PT6816-8 8" narrow planar mid/tweeter
$80 for pair of Dayton RS52AN-8 2" Dome Midrange (new)

$1500 for all remaining

While there is a bit of ambiguity purchasing a DIY loudspeaker designed by me. All I can say is that these sound excellent. Except for overall output level, everyone who has listened to the bookshelf speakers prefers their sound over the pair of Kairos (Jeff Bagby design) I built previously. They image very well and don't require any EQ to my ears unless I use them in my office as desktop speakers. I've built lots of speakers from LX521, Troels "The Loudspeaker" and really find their sound signature second only to the LX521. "The Loudspeaker" was fun because it had no practical output limit in a domestic setting. Of course they are 5.5" drivers so best crossed over to subs if you want to play loud but without or for near field they sound fantastic. There is just something special about this pairing of great drivers. I've attached the final simulated response captured as a screenshot. I can provide design files in SoundEasy but can't launch the app anymore due to lack of support on modern computers. If I remember correctly I did end up padding the tweeter down a little more by ear but you can always manipulate L-pad to your liking.

For references check out my eBay/Reverb rating (user jf4828 on both). I'm happy to do transactions through those platforms if you prefer but would have to charge a bit more to cover selling fees....

I'm happy to snap some more photos if needed; just let me know what you'd like to see 🙂

Joel

$145 shipped CONUS. These drivers have been mounted briefly, but not seen any use beyond testing.

Hello everyone. My name is Andrés and I'm from Argentina.
I use Google Translate to write and be understood.
Vine a este sitio buscando información, ayuda, consejos y curiosidad.

Hola a todos. Me llamo Andrés y soy de Argentina.
Hago uso del traductor de google para redactar y que me entiendan.
Llegué a este sitio en busca de información, ayuda, consejos y curiosidad.

I'm looking for a schematic of a transistor amplifier. This isn't a push-pull amplifier. It's a different setup.
I've attached a simplified diagram to clarify the order.

Unused. $75 shipped CONUS

Brand new. $60 shipped CONUS or $45 local pickup in Dayton Ohio

Found

Looking for 1 complete crossover & mounting plate for the Realistic / Radio Shack Nova 8B or Optimus 5B speaker system. Prefer a complete one with uncut wires. Will take a pair if necessary.
Thanks!

Login to view embedded media
Crimping is king these days.

I am considering two DACs one (ZEN Air DAC) uses the Burr-Brown Native DSD1793 DAC chip; the other one (Topping DX3 Pro+) uses the ESS ES9038Q2M chip. Which one is better?

Hello all and thank you in advance for any advice you can give!

I'm a long-time music lover but relatively new to tube audio equipment. I built both the TU-8200 stereo amp (currently running KT88's and with upgraded caps) and the TU-8500 preamp. This stereo is used 99% for phono input (Project Carbon Debut EVO with upgraded sub, platter, and cartridge). Currently running through Fostex BK-16 Folded Horn spearkers I also built.

I've been generally very happy with the sound. The volume is ample for my moderately sized open living room/kitchen. I rarely use this stereo with headphones.

However, lately I've been reading a lot about 300B tubes and other options and the TU-8900 looks really intriguing. I am wondering, how much of a difference am I going to notice trying out the 8900 with my setup. Open to trying different speaker and/or preamp options in the future, but the first step would be the new amp.

For reference, my musical taste is varied but a large amount of what I listen to is both old and new soul and funk with a healthy amount of fusion and jazz thrown in. Lettuce, Tower of Power, Stevie Wonder, Bill Withers, Weather Report, Earth, Wind & Fire, Amy Winehouse, Khruangbin, Donny Hathaway, The Meters, Otis, JB, Aretha, Herbie, well, you get the picture. However, I listen to a fair amount of other stuff, occasional hip hop and electronic music, jazz, psychedelic, etc. I grew up on classic and 90's rock. I don't listen to rock as much anymore but occasionally throw on things like Led Zeppelin, Pink Floyd, Soundgarden, Alice in Chains, Radiohead, Flaming Lips, etc. Rarely play classical and occasionally some folksy stuff (Dylan, Joanna Newsom, Joni Mitchell, Cat Stevens, etc.).

So I guess I'm asking if, for my musical tastes, will the 8900 offer something above and beyond what I already have? If so, for the music I frequent, would 300B or 2A3 be a better choice? At the price of these tubes, it would get a bit costly to do much tube flipping.

Thanks again!

Best,

Josh

If anyone’s got some spare BF862s (not the sketchy ones from eBay - tried those, definitely not legit), I’d be happy to buy at least 10 pieces.

Hi people 😀

I have necessity to build a kit similar to this
http://www.siliconchip.com.au/cms/A_101145/article.html
For the dog of my neighbor. (I cannot sleep anymore 😡 )

what type of piezo tweeter can I use?
which is it the maximum power that I can use? 😕

I have to look for datasheet of the manufacturer..

Hi All,

I'm Brendon from Perth Australia.
Thank you for welcoming me into this community...

I'm a newbie in the audio world and look forward to learning more a d enjoying the journey.

The most important thing in an EMI filter are the coils, these must have a particularly high permeability and a very low internal resistance, smaller coil values and very large X2 capacitors are best in order to achieve a lower cutoff frequency of the filter, be careful with Y capacitors, too high values can trigger the FI!

The last picture shows a Chinese DC filter and EMI filter board, which sits directly in front of the transformer in a ChipAmp amplifier.

I had a few of these laying around.

6 sets are allocated to Poland.

The rest are up for grabs.

$10/each .+ shipping at cost.

R

Rod's instructions say "a 0.5°C/W heatsink for normal hi-fi use if the quiescent current is maintained at the minimum recommended of 20mA."
I don't know what to do with that.
This is the heatsink I was considering and I found this calculator, but I'm not sure what value to use for Ts (max).

Hi there !

After an attempt to design a bluetooth DAC, with questionable technical choices, I decided to be reasonable and make an S/PDIF version.
The DAC is still based on the PCM5102A chip, without additional preamplification stage, and the 100x50mm 4-layer PCB receives one ground plane per layer, connected together by vias.

I will use this module for S/PDIF to I2S conversion: https://www.audiophonics.fr/en/inte...spdif-to-i2s-dir9001-24bit-96khz-p-17274.html
For volume control, I'll use this: https://www.audiophonics.fr/en/preamplifier-modules/motorized-volume-control-board-50k-p-15006.html

From what I understand, the DIR9001 module will synchronize to the S/PDIF clock, and the PCM5102A will also synchronize via the I2S bus. I still connected the MCK pin of the DIR9001 module to an oscillator, so the DAC should keep running correctly without an S/PDIF signal, because my Tripath amp does not like to operate without a source.

I placed an LC filter at the 12V input because the DAC will be powered by an external SMPS power supply. Please tell me if the values of this filter are correct.
As advised for my previous design, the low noise 3.3V LDO is cascaded to a much larger 5V LDO to lighten its workload.

As this design was quite conventional, I couldn't resist adding a quirk, a high pass RC filter, for optional use.
Indeed, I chose the PCM5102A because it is the only decent DAC chip that I felt capable of implementing, being a beginner. But I know that it tends to be a little too generous in low frequencies.
So I added this high pass RC filter which cuts at 48Hz in the hope of being able to obtain more controlled and clean bass, if the need arises. I can use capacitors with significantly different values to fine-tune the filter. Let me know if this is a bad idea 🙂

EDIT : I just saw a big error on my high pass filter which in reality is a low pass 🤣. I am going to correct this and I am thinking of using a relay in order to be able to bypass this filter easily.

And here are the pictures :

Looking in another thread whith an unusual current limiter an idea struck me.
Here is a simple current limiter working on the base current of the output transistors.
Of course there is some potential problems. We must have output transistors with a known current gain jus as well as the drivers and the limiters.
And when the base current is limited the fast switching will also be limited. But it is simple and nearly fits a SOA with max current at low voltage for the output tranistor and 0 current with max voltage. If the current gain is 100 for all transistors max current is about 15 ohm from full voltage. Max current 5,3 A in this case and the half with the output short to ground.
The IS 1 and 2 is just for DC simulation.

I'm planning to build the above crossover and have a 25ohm rheostat I'm hoping that there is some way to use for P1.
Is it possible to sand a portion of the metal rheostat body and solder the 15ohm resistor to it as a 3rd lug, or do I just
need to purchase a wire wound 25ohm potentiometer with 3 lugs? Rheostat in question is pictured below.
Thank for your help.

Hi, my name is George, living in Germany.

I am looking for interesting discussions about audio/hifi equipment and sound improvements that I can use in my home.

Hello,

I'm searching for the latest firmware for my Marantz NR1504.

The reason?

Certain internet radio stations don't play anymore on my Marantz NR1604 and NR1504.

For the NR1604, I found, asked and received the firmware on this forum. Thanks again. And this solved the problem.

So I'm looking for the firmware now for the NR1504.

Many thanks in advance!

Stijn

I'm finally restoring my inherited Quad 303!

I'm following this guide:

https://www.rs-online.com/designspark/refurbishing-a-classic-quad-303-amplifier

I've replaced all the capacitors and everything went good 😉

Now to the problem:

Adjust RV100 for 33.5 volts between tags 5 and 9

One of the channels gives me an irregular reading of 38-41v with the pot all the way up. With the old pot setup it was reading 60v.
I only had to make minute adjustments to the power supply pot and the other channel.

What do you guys think is the culprit?

I'm a noob with a soldering iron.

Hi!

Back with a Sony TA-F770ES. The pour thing has blown its output mosfets.
These 2SJ200/2SK1529 seem pretty close to the 2SJ115/2SK405 in the Luxman LV series that I successfully replaced with IRFP340/9240 with only very minimal modifications. I know from experience that these Sony amps can be pretty unstable, is there anyone that has tried this replacement before and/or can simulate what results this would give and if there are any mods that have to be done to the bias circuit for example ?

Thanks !!

Hi all,

I am building a class D power amplifier and got a bit confused on how to read the specification on the power switch and whether it will actually work for the purpose.
This is a 200W mono construction, 400VA/40V toroid transformer with 200 uF filter caps and a 2 second softstart from the late Newclassd solution

The power switch I have bought is specified to 10A 250V, but got a bit confused on the fuse power specification on 2W for one-pole and 1.6W for 2-pole. Have I bought the wrong switch for this application? Any suggestions to what spec I need - both for the switch and what fuse to use 🙂

The switch: https://docs.rs-online.com/dd66/0900766b81148d4e.pdf

and the specification sheet:

I've no idea how to read a circuit diagram. Can somebody please tell me the transformer output voltages on page 10?
Thanks in advance.

Hi guys,

What happens to a voltage regulator when started up on a variac?

I am about to test a tube power supply with a regulated 12.6v heater supply (lt1086) and a 265v regulated b+ (treg)

My question is will this hurt the regulators in some way?

My guess would be that there is no ill effect. That the regulators simply won't regulate when their input voltage is below their minimum drop out.

My punny brain can conjure some horror scenarios when this would cause wild current flow but I am guessing this is my feeble mind displaying it's feebleness.

This will be my 2nd go around at building multi-way speakers and have decided to try a MTM configuration. When designing the crossovers, is there anything I need to do differently than I would do in a TW 2 way crossover? The mids will both be the same make/ model. I've ran some sims through xsim and removed one of the 2 mids after building one to see if it reacted. It did but not in the way I had expected. The SPL actually went up when disconnecting the 2nd driver. 1st pic is with 1 mid. Pic below it has both hooked up. Would that be normal?

Guten Morgen involved people,
I would like to show you nice solution for MM cartridges from Nick Sukhov. He is a legendary audio circuit designer based in Kyiv, Ukraine.
MM Phono stage-XXI (Su-XXI) by Nikolai Sukhov, thanks to the "aperiodic" HF correction invented by him back in 1980 [first described in the article "High-quality preamplifier-corrector" in the USSR Radio magazine No. 3/1981 pp. 37-40, which became “The best publication of the year” in 1981] allows you to get rid of the input circuit resonance "MM head inductance + cable and phono stage input capacitance", due to which, above the resonance frequency (usually in the region of 14 ... 16 kHz), a frequency response decay is formed with a significant slope of 12 dB / octave ( like a second-order low pass filter). With aperiodic correction, such a drop is eliminated and the sound of $50 MM cartridges becomes as transparent and detailed as that of top MC k$ cartridges. Similar circuit solutions appeared 20-30 years later among high-end Phono preamps under the names "Neumann pole", "Damped EQ", "Enhanced RIAA - eRIAA", "Phædrus Phlux active phono cartridge". Thanks to the original "passive cooling" solution with 150 kOhm input resistor instead of 47, the Su-XXI provides an unprecedentedly low noise level of -85 dBA in full compliance with the standard input level of 5 mV @ 1 kHz (and not the "maximum input" - a typical marketing trick) and with an equivalent input MM-source 500 mH / 1 kOhm connected (and not the "shorted input" - another trick of the steamers). Finally, thanks to the use of a high-output impedance voltage amplifier stage with a load Z(f) in the form of an RIAA-chain (overall gain 1+Z(f)/R, voltage amp open collector stage gain is also proportional to Z(f)+R, so loop gain is almost constant across the entire audio band), a "passive-active" frequency-correcting circuit is formed with an almost unchanged feedback depth from 10 Hz to 50 kHz (55 dB constant loop gain). This design of the deep RIAA freq response correction of 40 dB eliminates the “diseases” of both excessive gain at high frequencies and insufficient gain at low frequencies, which provides both a high stability gain margin (22 dB) and a uniquely low THD of 0.00006% at a nominal input voltage of 5 mV @ 1kHz and 0.0006% at +20dB overdrive.

Anybody has a reference for a simple ADC board with an spdif output? I prefer coax output but optical is also an option. 16/44.1 is plenty for the use I have in mind.

I'd like to build one into my preamp so that all analog sources get converted before switching and sending out of the preamp. So it is for my fm radio, an old tape deck, turntable etc. DAC board are 13 a dozen but ADC boards look scarce.

I have been printing another large MEH. Finally got it finished and vaguely measured. It is 630mm wide and 360mm tall. The horn is 350mm long without the comp



Here are the measurements:

The measurements were taken with the mic at the mouth in a small room as in the image above so they aren't ideal but I will try and get some better measurements soon.





With the sims I had managed to get it up to around 2khz however it drops off rapidly above 1.3khz. I have managed to get smaller drivers up to 2khz before so thinking it is cancellations across the cone?

I might try doing some modelling in Akabak of just the front chamber and taps to see what I end up with.

Hello everyone,

I have an Audison SR1DK with a weird issue. The output at startup is not at full power and it gradually rises to full power. Changing the gain does not affect it much, and the signal is clipped when the gain passes a certain threshold.

Also, does anyone know the value of this capacitor (C128)?

Hi to all. I love music and have my dedicated room to listen and HT. I had a great pleasure to treat it myself, although still not perfect it has been improving. I am here to learn mostly and to share some of my experiences.

Best regards,

A. Duarte

I bought a pair of these as basis for some experimentation.

I have listened to them a bit 'out of the box', but did not really like the sound. A bit harsh and a bit weak in the LF bass was the impression.
After some simulation, I have drawn the conclusions that the feedback DC cap could be increased (120uF), and so can the input cap (3,3uF). That could improve the bass slightly.
I put a 1000u bipolar for the feedback (to the left of the grey input cap), and soldered another 3,3u in parallel to the input cap on the back of the PCB.

From measurements I found that bias needs to be increased to reduce distortion. I added a 5k trimmer in the position seen on the picture and tuned it to the minimum Iq for lowest distortion at abt 1W. A value of 4,3k seemed to do it on both boards, and that resulted in a emitter to emitter voltage of abt 7mV, which translates to abt 16mA per output pair.
Distortion now stays below -100dB at abt 1W 8ohm. Improvement was abt 10dB with bias adjustment.

I'm looking to build a compact and lightweight speaker for bass guitar and electronic drums. I'm looking for 110dB at 40Hz at 1m in 4pi space. It may be a 2 or 3 way design.

At the moment, I've modelled NE265W-04 in a 30L box tuned to 33Hz in winisd. This is giving me 108dB at 40Hz at 23.6V (150W) in winisd so 102dB in 4pi. It's a 10 inch speaker and weighs 5 lbs.

I'd like to keep the box volume about that size. And I want to keep the weight of the driver down. And the power manageable. And I need a 4 ohm speaker. And 8dB more output without throwing 8dB more power at it.

Wishful thinking or can I do any better?

Is there a way to search for drivers that will work in that size box and predict the output at 40Hz without modelling? Just something to get in the ball park so I don't have model each and every speaker? Ideally a quick glance at the ts parameters should tell me if it's suitable.

I did try sorting based on peak excursion times cone area. But that doesn't tell the whole story.

I'm just trying to figure out how to use my fancy LCR meter. All I want to do is measure the impedance of a 1:1 audio transformer and compare against the data sheet.

Data sheet says impedance should be 15K with a 600 ohm load but the LCR is spitting out 3.2k. I have bought the handheld DE-5000 to verify the first LCR but ability meters agree.

All I have to do is hook a 600ohm load up to the secondary, right? I'm totally confused

Sold

Sold

Hello everyone,How does kapton and enameled cooper wire stick together in the speaker voice coil and does the cooper wire not lose after winding, what is the methods curing done by baking at high temperature or is there an adhesive on the kapton surface,

Some speaker repair technicians said that there are self-adhesive versions of cooper wire and self-adhesive versions of kapton material and both are activated with ethyl alcohol and then baked in 350F for 45 minutes to make them stick together,If anyone knows exactly how this sticking process is done by speaker manufacturers, I would like to learnThank you very much in advance

Just an interest,

How old do you want to be when you retire?

Any thoughts about jacking in and getting the "Good Life" or is it looking a bit doggy..

Any pitfalls from those that already have...

Thought it might be fun to see what the thoughts are..😱 or

Victor meldrew always comes to mind....
http://www.youtube.com/watch?v=c1qs_eFRXqs&feature=related


Regards
M. Gregg

I forgot how long I have these pcbs; heck, even added (just for giggles) one small cap, just to have a reason to make new gerbers
Anyway, N-MOS/Schaded N-MOS/SIT source follower, loaded with P-MOS in Mu-Follower arrangement, blatant shameless flipped Xerox of Papa's BAF 2015 amp Mu part

Mosfets are IXYS hockey pucks
SIT can be THF51, 2SK180, 2SK182

Single rail supply, GND up, neg 60Vdc down (remember that GND is State of Mind - I did use +/-30Vdc PSU from my T-Bed 2 accordingly wired, without using center rail)

Iq 3A2

Necessary pictorial info about "main" pcb


(late) edit on Jan 25. 2024. - change of Mu resistors values, as per Ben Mah's suggestion - post #17, https://www.diyaudio.com/community/threads/lazy-singing-bush.388164/post-7069779

in short - 0R2 at SIT side, 0R3 at puck side

Some pairs of heatsinks for amplifiers, salvaged from dead AVRs:

Two pairs 18,7 x 15,3 x 4,0 cm











One pair 19,7 x 13,5 x 5,0 cm









Make me a fair offer ...

I've been looking into Frugel-Horn XLs as I'd like to build my own speakers for mostly low level listening. Having limited woodworking experience and tools, I'm looking at a kit from KJF Audio but have a few questions I'm hoping the hive mind may be able assist with.

Firstly - does anyone have experience of the KJF kits and whether they are a good quality product?

Second - would a Pluvia 11, Alpair 11 or Alpair 10.3 give me the least bright sound in the XL box?

I tested both using DATS3 and they look fine. These are perfect for 1st order XO or a 2-way system. Here's the link to PE item page:
https://www.parts-express.com/pedoc...rs225p-4a-reference-series-specifications.pdf
Current price is $66 each. I'm asking $100 for the pair - i'll cover shipping in the continental US. Who knows what will happen to the PE price once the import tariff is implemented.

Hi.

Handles in PA-speakers: I have used 2 different options:

1. 100% DIY with a handle-cutout in the plywood and somesort of "box" behind
2. Store-bougth handles (flip, inserts, metal, plastic).

1) i cheap on materials and typically takes up more volume. 2) is a bit more expensive, less flexible, but takes up less volume and is much faster.

Please share your novel or orginal ideas for handles.

Kind regards TroelsM

I noticed on some of my Bliesma M74A mids there was an intermittent buzzing sound around Fs (400 - 500 hz) which disappeared when I put pressure on the small WG front flange portion.

Underneath the foam flange sealing gasket on the under side of the driver, there are 4 small allen head screws. I've discovered some these screws have bottomed out in the holes before the full clamping force is imparted on the VC ring asy that is sandwiched between the two metal parts. I did find some excess powerdercoat inside the screw holes, keeping the screws from seating at full depth inside the holes. Chasing the threads with a bottoming tap would likely be the most correct way to fix this, but I don't have an M3/0.5 bottoming tap or thread chaser, so I had to improvise and came up with the following simple fix...

I've inserted a 0.5 mm stainless steel washer under each of the 4 flange screws, which still allows the head of the screw to sit flush with the flange surface.

Important - only deal with one screw at a time !!! You don't want to risk the VC going out of alignment, so be careful. These are precisely aligned components you're dealing with here.

There is a light thread locking compound on these threads, so go slowly and carefully when removing the screws to avoid thread damage. Tighten the screws back to about 4 - 5 inch lbs. (If you need an exact torque figure, this is about right).

You dont need thread locker if you tighten the screws down evenly. Once you mount the driver, it will automatically be compressed together by the baffle screws, so there won't be any chance of the 4 small screws backing out on their own.

The small buzz was completely cured with this fix. It was noticeable on 2 out of my 4 M74As. I'm likely being very picky here, but I didn't want to risk a VC misalignment or shifting with these screws having an uneven clamp load on the VC asy. Again, once you mount the driver, it should no longer be a concern.

Hello all, i have a Marantz 8b project for sale if any one is interested.
I lucked into this unit a couple years ago & never got it to work.
The unit is missing the guts of one output transformer but the other is there. I did resistance checks on power tranny and all seems fine. choke is also good as well. It will come with covers.
I’ll post some pics shortly.
Thanks, Mark

Hi.

I thought that all compression drivers used the same thread? When trying to mate Eminence Asd1001 with an mrh-80 horn from Monacor it works fine for the first 5-6 turns, but then it jams up. Data sheets for the parts have the same thread. Comparing with a Noname driver the asd1001 thread is slightly off.

Anyone else tried something like this? I'm tempted to cut of some of the internal thread in horn, but it seems wrong. It should fit?

Kind regards TroelsM

I recently built an LM3886 amp, which I posted here. I read that some prefer the sound without the feedback capacitor (Ci on the datasheet) and was wondering why.

I know the DC offset will be higher without the capacitor and I plan on trying that the next time I open it up as I built mine with the feedback capacitor.

My guess would be different bass response but my training is in repair not engineering.

My question is: Can anyone describe the sound difference with and without the feedback capacitor?

Thanks.

I'm about to start my first DIY audio project and build my first active speaker using some passive speakers I already have. The speakers are from a brand called Sonab, and I’ve had them for many years (fuge series).

My goal is to build an active speaker system that will:

• Connect with other speakers (master-slave setup),
• Include Bluetooth (with high transfer rates),
• Have advanced audio inputs,
• And of course, use a well-designed acoustic enclosure for the speaker.

I studied Electrical Engineering, and during my degree, I took some courses on Signal Processing, including Audio DSP, so I’m not afraid to dive deep and even build the system using separate components if needed. I’d love to end up with a robust system with great sound quality.

During my research, I found two interesting all-in-one boards that seem to cover most of what I need:

• TinySine TSA8800B
• Wondom JAB5 AA-JA33286

Both are based on the same DSP (ADAU1701) and offer similar power output, which seems to match my needs.

However, after reading some threads here on DIYAudio, I noticed that some people don’t fully recommend using these boards and suggest going in another direction—usually more expensive when looking at a full system.

Since I’m willing to explore and buy separate boards to build my own setup, I’d really appreciate some advice:

• Is there a better DSP/audio processor you'd recommend that has good performance?
• Has anyone here used TinySine or Wondom (especially JAB5 or TSA8800B) and achieved good sound qualityafter proper DSP configuration?

For reference, my speaker will be around 220W RMS total, built from one woofer, two midrange drivers, and one tweeter. I still need to measure each driver’s individual power, but I couldn’t find full specs yet.

Thanks in advance for your help and tips!
Shay

I got this amp from someone so I could attempt to fix it as a way to practice and learn how to repair class d amps. I don’t know what happened to the amp, but half of the PS fets were shorted or exploded, all of the output fets were shorted, there was a short on the 2113S. I checked all the gate resistors they all checked out good, I checked the Zener diodes and they all seem fine. The amp will power up fine, rail voltage is present, high side 59.9V, low side -59.2V. +15vdc and -15vdc is present. However, when audio signal is introduced the amp immediately goes into protect. It does the same if the switch is moved from master to slave. There is .129mV of DC offset.

I don’t know if this amp should have significant dc voltage on pin 16 of the 494 when main power and ground is applied but remote is NOT applied. I’m wondering if this could be the issue because the amp sits at 3.226V with B+ and ground and no remote applied. When remote is applied in the absence of an audio signal, the voltage on pin 16 drops to 2.949V, then when audio signal is applied, voltage on pin 16 jumps to 7.918V and the speaker relay and protect led are triggered. Pin 15 has 4.949 when remote is applied.

I’ve rechecked all of the fets and there are no shorts present. I could find no obvious shorts in the inductor on the output. The amp doesn’t exhibit obvious signs of a short condition on my bench power supply, the supply doesn’t go to constant current mode.

I’m sure I’m missing something, if anyone has any ideas of what I should check, please let me know. Thanks in advance.

I am trying to revive a Luxman L-11. This amp hasn't been used in years and needs the DC Offset adjusted and I am sure that the BIAS will require this as well. If anyone has any information on this or has a service manual that they can either share or sell, I would be most grateful. I have found the schematics for this amplifier but there in nothing there that helps with the adjustment of the offset or BIAS.
Thank you all.

Hi Folks!

I'm designing a linear dedicated PSU for the Behringer DEQ2496 (and DCX).

I need an advice. In this current draft drawing, the 10v ground is connected to the 15v ground. I don't know if I can connect 2 ground lines for 2 different transformer/rectifier.

Enclosed is my last draft.

Thanks for your help.

Stephane

Hello all, trying to down size inventory a bit & have a pair of Stephens Trusonic 150cx 15” full range Speakers in very good condition, no tears and both in working condition. I had these mounted on open baffles & do sound great.
Let me know if interested. $500obo.
Regards, Mark

Hi There
I need some 6800uf to 10000uf caps. Screw-In type. 100V
4 or 8 ,I'm not sure yet.
Let me know what you have.
Thanks 👍

Came across a paper sort of similar in nature to Bruno Putzey's work on ferrite distortion/noise in class D amps. Please see attached.

It appears to be something similar to what I have noticed in much lower power DSD dac circuits where ferrite beads are commonly used with the intention of reducing noise problems, but may in actual practice have some adverse side effects by way of adding some distortion/noise of their own.

So my local place that I had purchased from closed down.
Need to call around but wanted to inquire where you guys ordered your wood from?
If I could get it precut assume shipping cost reduced.
Looking to get 6-8 full 4x8 sheets. Baltic Birch no filler (I've come across a website selling BB Baltic Birch but looking it it seemed to have filler with outside veneers)

Any other Marine grade plywood or other that is just as good? (density)
These will be tour grade subwoofers (2 at 507Lt box) covered with Duratex or Raptor Liner.

One of my early projects: the Objective 2 (or O2) headphone amplifier, built as a preamp. 4 RCA inputs with rotary selector, one stereo RCA output. Includes 15 volt AC adapter (this is an important detail, don't use a 12v DC adapter!).

Sold

Asking $40 obo, local pickup in San Francisco preferred. Will ship ConUS at cost.

I have spent several hours over the past two days searching for size/shape compatible surrounds. The most likely candidate so far are surrounds from Simply Speakers.

The surrounds attach to the underside of the SBX500 woofer discs which is a shiny metal surface - presumably aluminum.

Two years ago I attempted surround replacement to the undrside of 5" woofers with a poly cone and those surrounds coincidently came from Simply Speakers. That attempt was not successful due to the awkwardess of accessing the underside of the cone and the clear, fast setting adhesive provided by Simply Speakers. I think that clear glue was rubber based. There was not enough time for me to position the surround on the cone before the glue got too stickey to work with. They then sent me some conventional slower setting white glue.

I expect that gluing a surround to the underside of these Technics SBX500 woofer discs will be fiddly and somewhat time consuming. My question is will the conventional white' slower setting glue bond properly with the metal surface of the disc's inderside?

The attached photos are as they are now. The residual old surround material on the disc's underside is still in place. I am debating on attempted removal by blade & scraping or trying some type of solvent.

For Sale: Elliot Sound Products P-101 Amp. One of my favorite amps, and has been used on conventional, planar and Electrostatic speakers...

Powered by a SMPS and housed in an old Hafler Chassis. Looks and sounds great...with +/-60v rails, over 300 watts @4 ohms. Exicon output devices.

$350 + ship, or pick up in West sub of Chicago...

Amp built years ago when TA0103A were popular - with a Hypex SMSP400 SMPS. Turn on and Turn off thump (these Tripaths were notorious for these thumps) have been mitigated with delays.

Sounds great / clean. See attached pics and Application notes.

Ships from West sub of Chicago

How's $450 + ship? CONUS only please....

Hey all, seeing quite a few Yaquins on Swap Meet, so thought to post mine...

Yaquin MS-110B Tube amp. 50 watts/channel. Biased set and ready to go. New-ish tubes that test very good on my tester. Comes with original manual, fancy remote and cage removal tool. Slight scratching on top from cage, but very clean condition.

Output power: 50W + 50W (6Ω)
Harmonic Distortion: ≤ 1.9% (1kHz)
Frequency Response: 10Hz - 65kHz (-2dB)
SNR: ≥ 85dB (A)
Input sensitivity: ≤ 0.3V (1kHz)
Load Impedance: 4Ω-8Ω
Tube: KT88 × 4 12AU7 × 2 12AT7 × 2
Dimensions: (length) 300mmX (W) 420mmX (high) 200mm
Weight: approximately 25 kg

Features: (from ebay ad...quite funny)

• Power tubes use the latest improved KT88-98 and strong output push-pull circuit.
• Preamplifier part is as "SRPP" circuit and excellent "long tail" type inverter circuit. So that a wider frequency response and better sound quality.
• Audio output transformer dedicated silicon steel imported from Japan (0.35mm thick) and oxygen-free copper wire and special high-strength multi-layer winding process grouping production (divided into 15 layers), so that the machine wide frequency response, ensuring high the machine, , the low-frequency sounds good, transparent and powerful.
• The machine adopts well-know brand dedicated audio BC capacitors and also Philipps (MKP) nonpolar capacitor.
• High quality gold-plated resistor, the main channel using a dedicated sound Japan (ALPS) volume motor potentiometer with quiet background music, noise low, no sound pollution and durable.
• High voltage power supply for the automatic delay control, can effectively extend tubes life.
• Switch between ultra-linear (UL) and three poles (TR) connection mode, to meet different user needs.
• Function with remote control and high quality headphone output.

New on ebay around $1200...How about $750?

Pick up in West sub of Chicago...or can ship for $$ (55 pounds)

This thread's purpose is to assist builders with their Aleph Jzm kits.

For general discussion, customization, parts substitutions, or anything unrelated to the kits, The Aleph Jzm thread is perfect.

The goal is to have this thread be a quick source for relevant information for kit builders. It will also be used as a source of information to update the Aleph Jzm Build Guide. At this time, comments are not active in the build guide.

For builders specifically needing help with their power supply, please search for a thread supporting your specific power supply, create a separate thread as needed, or post your question in the The Aleph Jzm thread.
For those needing assistance with their amplifier boards or overall assembly and wiring, please post the following:

1) The current step # from the AJzm build guide.
2) Well-lit, in-focus photos of the build in its current state.
3) A description of the issue or question.

The purpose of this thread is aimed for people who (or recently completed) are currently undergoing construction of the Elektor Preamplifier 2012 that was published in April, May and June 2012.
See these links.
https://www.elektormagazine.com/labs/preamplifier-2012-1-introduction-and-line-intonevolume-board-110650

http://https://www.elektormagazine.com/magazine/elektor-201204/19844

Your constructions, ideas, problems, images etc would be valuable for other constructors to view.

Although, most readers will be familiar with the Elektor project, below i have list some basic details below.
Printed Circuits Boards for this project are available direct from Elektor: -

LLLL BOARD (110650-6V120) £14.95
POWER SUPPLY BOARD (110650-5V110) £16.95
FRONT PANEL BOARD (110650-4V110) £11.95
INPUT BOARD (110650-3) £22.95
Preamplifier 2012 (2) (110650-2) £22.95
LINE-IN/TONE/VOLUME BOARD (110650-1) £22.95

I asked the question some months back: How do our loudspeakers compare to expensive, high end, HIFI brand loudspeakers?"

I have answers.

The Short of it:
For those of you who do not want to read this entire write up I will be kind and put my summary up top in a bullet list. There was 3 of us who went. One musician, one loudspeaker builder, and one wife who only ever listens to the system the former two have and doesn't know how any of it works. We listened to 60 systems in one day. Back to back to back. We then came home and listened to my systems.

The BAD

• Most of them do not sound good
• Most of them have a roughness to the upper mids that just sounds terrible. They use these great drivers but drive them straight into their cone resonances. This was the #1 thing we all found wrong with about 80% of the systems
• I swear they pick their crossover points at random. Their crossover networks are pretty goofy
• A lot of them have phase issues. You stand up and it just sucks. You move to the left and it sucks. You have to sit directly center
• Some of them were amazing. These were generally ones where the loudspeaker designer was right there in the room and you could ask him questions. I will get to these units in a bit
• Anything with DSP had a roughness to it. Every single one of us, by the 3rd floor, could walk into a room blind folded and tell you if it was a DSP system or a passive system. Passive ALWAYS sounded better. We listened to about 60 systems back to back throughout the course of a day. DSP to the 3 of us = no good. Was not really subjective. It was objective.
• A lot of them beam really badly. The ones that don't, have a harsh upper mid range
• Do more expensive drivers sound better? Yes, if you use them properly. Saw some $400 drivers implemented horrendously and some implemented properly. And everything inbetween. But mostly the former.

The good

• A couple of systems were just incredible. All of these except two had the loudspeaker designer in the room.
• The better systems used either bespoke of expensive drivers.
• There were a couple mid tier systems that sounded really good.

You can skip the individual review and go to my comparisons with my own loudspeakers at the very bottom
Lets go through one by one now (I am not going to include most of the bad ones. They sounded so bad I had to just get out of there. If it isn't listed below here and it was at the show, it sounded like crap):


This 4 way was great. It had dynamics and a lightness. Lows were washed out but it was still good



This was ATC. I hear people praise their old mid dome here so I checked them out.

This two way was horrendous. One of the worst speakers at the show. The driver on the table is what they were showing off. Do not buy this thing. It was sticky, like someone covered it in honey. I would guess in your house it'd be covered in dust within a couple weeks. Bad, just all bad.


Morel

These were great. The mid is the one up top and is ported. The woofers down below are also ported. These were REALLY good. I spoke with the engineer about how they don't measure or simulate well. He explained their motor design in detail. It will not simulate right because their design is so different. They have special software they have to use for their motor designs. The price point of morels now looks very attractive to me.



This one wasn't playing. I just thought it was a fun design with the dual AMTs in front of the woofer


MTM Illuminator design. What's not to like? Horrendous upper mid range. So sharp and attacking. Not good. Lows were good, not very dynamic. No idea what they cost but its too much. Feel like the designer dropped the ball here.


I will now never build a line array. This thing just sounded odd. Like a blade of people singing on the left and then a blade of instruments on the right. It was all washed out vertically. Hard to explain. Not a fan. None of us liked this, all of us thought it was just strange sounding. And not strange in a good way.

Full range driver build by Songer. Second best sounding full rang behind a Voight pipe Alpair 11 build. This thing was great. Good dynamics, good upper mid range, very nuetral, good dyanmics. It had it all. It is a giant full range so it beamed like crazy. Move your head left or right and the tone changes. But still very good.


I think these are called frugal horns? Big woofer and a compression driver. Engineer was in the room. Not my cup of tea but the BEST compression driver I have ever heard. He crosses these to the woofer at 700 hz. Pretty impressive and fluid, natural sound out of these. The big woofer lacked dynamics to say the least.




Triangle Art

These were bad. Like just plain bad. Maybe they would sound good if you were 60 feet back in a big room? Crazy directional. Everything sounded muddy. All looks, no beauty.


AudioVideo Artistry

******* AMAZING. What do the Accuton driver's sound like? ******* AWESOME. End game design right here. Nothing topped these except their big brother which will be on this list somwhere. These Accuton drivers are insane. I think he has at least $7k, at LEAST, worth of drivers and crossover components in each of these.

Do expensive drivers sound better? In this case, YES YES YES, they ******* do. I had to shake this man's hand. Can't stop gushing over these.



Alright, we need to chat about these domes. This dome was, BY FAR, the best mid at the entire show. Everything else pales in comparison to these. I asked him if I could buy a set of the mids and he said I could. I just have to call Playback Distribution and ask for a replacement pair. I will be buying a set. Maybe we can get a group buy together? I'm telling you, you haven't heard ANYTHING like this before. These are like sorcery. I will be making a second post where I try to buy these. This is a game changing driver.

As a speaker in totallity these were AWESOME. They are small, but they blow out of the water almost everything else at the show. Another one where the engineer was in the room. I spoke with him 3 times today. Kept coming back.


These were ok. Harsh upper mid. Tweeter were good but they ran them too low. A lot of expensive stuff to sound like garbage. Crazy.


26" dual opposed woofer. It shakes the building. Sounds no different from my coffee table subwoofer in my office. This doesn't hit as low as my coffee table. Impressive...... if you don't have a coffee table that hits to 11 hz.




Tannoy

You like jazz? These are for you. Grainy, poor imaging, you are hyper aware that the sound is coming from the speaker. No low end dynamics. Great for trumpets and a saxophone. Pretty sure they were made for that.


My first taste of open baffle. My buddy liked them. I did not. Sounds all washed out. Someone moved a table and the guy had to jump on the dsp to correct the room again. Not for me. Zero bass


More open baffle. More of the same, washed out and not defined. These had bass because of the horn. That was even a little washed out.



Harsh upper mid. Looks cool, doesn't sound very good.


PS Audio

These are some of the best at the show. If you can tame a mid planar, nothing really compares for silky smooth vocals. Paul did it right. I have half a mind to use a planar mid for every mid I do even though I just gushed over those mid domes.

I wanted to build a DIY amplifier for my speaker. I just assembled it on a perfboard for testing, and when I tried adjusting the bias, nothing happened. When I checked, there was no bias voltage, so I started checking from the long-tailed pair and found weird voltages. I tried replacing the current mirror transistors (Q4 and Q3), and there was no difference, so I tried replacing Q5 and Q1, but nothing. Looking at the board, I don’t really see missing connections. I tried disconnecting the VAS, and nothing really changed. Where should I look?

Hello all 🙂

Just to introduce myself, have been modifying and playing with electronics, mainly audio, for years, in the early days often fixing them after I'd broken them ! Work in IT, networking, virtualisation etc and electronics is a hobby, for fun. Have a number of classic (old, British) transistor amplifiers all modified in some form or another.

Latest is Lehmann Audio BCL which needs fixing after somebody tried upgrading it and just went too far.

Looking to build more and fix less, I'd like to try building a tube amp.

Hello guys 😉

This is my current project. Its a MiniDSP style active crossover heavily inspired by Cyperpits Octavia. Its still a work in progress and most of all a experimentation/test bed for me to learn how to design audio electronics.

It's based on a ADAU1466, similar to what is used in the fusion amps. The goal is to have a stereo analog input, SpDif in and out as toslink and RCA, 8 analog outputs and a trigger out to wake up amps as signal is detected.

For now I have only finished my "DSP core board" The DAC's and ADC are just cheap aliexpress modules for now. I almost finished my own DAC and SPDIF-out board based on the PCM5102A's. The ADC board is also conceptually done but still needs a lot of schematic and pcb work. This is what it looks like on the inside.


When I get my own DAC and ADC board the connections to the DSP board will be done via ribbon cables with every second line being GND to ensure good signal integrety.
I designed it this way with seperate PCB's as it allows me to focus on one thing at a time without making it unnecesarily tight and expensive to iterate. I can then try different DAC's or ADC's at a later time without having to pay for a new DSP chip and vice versa. It needs a fairly big box to allow all the connections on the back anyway.. Each pcb is 99x99 mm so they stay in the cheap range at JLCPCB. Its a 4 layer PCB with SIG on top, GND, POWER and SIG/GND on the bottom. Im currently using a Wondom ICP5 to program the DSP instead of the expensive USBi as I had it on hand. However, I hope to be able to make my own USB programmer based on the freeusbi and integrate it on the board eventually. But the software part of that scares me a bit as I have zero idea how it works with windows drivers and whatever..

It all started because I was playing around with a Wondom Jab5. I really loved Sigma Studio but I really did not like the wondom quality. The noise floor was unacceptable and eventually one of the amplifier chips on the board just died.. Having fallen in love with sigma studio I couldn't just go with a minidsp and my fusion amps also do not allow you to use sigma studio even though it is beeing used behind the scenes in both devices. I couldn't find any other product with less questionable quality than the wondom or the likes...
So I got the brilliant idea of making my own xD
As a Mechanical engineer I knew that I was waaay out of my comfort zone. However, thanks to opensource projects such as FreeDSP, analog devices excellent documentation and engineering support, and youtube channels such as Phil's lab it seems it may actually be possible for me to make something that works 😍

The DSP board is working and the overall unit performs surprisingly well. I belive the limiting factors currently is mostly the ADC and to some extend the power delivery for the ADC's which will be much improved in my own design. However, I have some wierd issues that I am currently trying to trouble shoot:

1. When the ICP5 is connected I get a lot of audible noise in the speakers both white noise, a whine and some kind of periodical ticking. It goes away when the programmer is disconnected again. This was also the case when using wondom dsp's with this programmer. Im not sure if it will be different with a USBi or if its something with my design. I was considdering to add some kind of isolation between the ICP5 and my DSP but was afraid to overcomplicate things in the first go.
   Any ideas how to get rid of this? it is a bit annoying when experimenting in sigma studio.
   
   
2. I get a bit of noise and a periodical clicking noise as soon as I connect my AC/DC adapter. Even though my DSP is turned off (I only break the positive line, the negative is connected directly to the DSP board) and no source is connected. This is the adapter i use: Ac-adapter-100-240v-to-12v-3a-dc
   I also tried a 7v mean well one, while it gets significantly better its still there. Not sure if theese adapters are simply not suited for audio, or if my power interface is to simple. with limited knowledge on this matter i pretty much coppied the Octavia power input with some small changes (added a fuse and a diode to the reverse polarity circuit).
   
   
   
   
   
3. I am having some wierd EEPROM issues. Most of the time it works as intended but sometimes it just refuses to write the program to the EEPROM. The wierd thing is I do not change any settings related to the EEPROM to stop it working or to get it working again. It seems pretty random. Its not related to on time. Can this be a SPI noise thing? related to the ICP5 (guess not because sigma stuido can talk to the DSP just fine)?. Faulty EEPROM?

Please critizie all you want, I want to learn from this 😀

I was not paying close attention, but, a whole range of WIMA caps was knocked out by a lack of film to make them with no hope to replace them

The EOL was sent of Feb 28 2025 and last order was march 12th. Thats pretty dramatic.

🙁

https://www.mouser.com/PCN/Wima_WIMA_Letter_MYLAR_PET_PEN_27_02_2025.pdf