I bought a 1000A. Just replaced ALL the electrolytics, oil caps and a few others. New diodes. Works and sounds great except when playing it will make random popping noises every minute or so. I tried wiggling all the switches and the control pots are cleaned but can't seem to find out whats doing it. Any suggestions?

Up for sale:
10,000uF/63V Vishay - MAL225658103E3 - 4pc, $10.00ea
4,700uF/63V Vishay - MAL205018472E3 - 4pc, $10.00ea
10,000uF Panasonic - ECO-S1HA103EA - 4pc, $6.00ea
Condition - Brand new

I am looking for an owner of Sibelius speakers who is also able to perform sound measurements. I am building a Sibelius clone (see other thread) with the Markaudio Alpair 10.2 or 10.3 and would like to have measurement data to be able to tune the speaker similarly. I would like to see a measurement from 20Hz to 20Khz with the microphone at 1 meter from the driver and a 2nd measurement with the microphone just in front of the bass opening. I am very curious how well the Sibelius cabinet supports the driver.

A new thread to discuss DIY guitar pickups.

I recently built one using six electret microphones. Every other one is wired out of phase with the adjacent mic. The set of six therefore cancel, for far field sounds. Each is arranged to be below the corresponding string, which is near field to the mic. It works pretty well - I've had it out on stage at an open mic more than half a dozen times. Other players say it sounds good. Different sound than you'd get from a piezo bridge pickup or stick-on puck.

Why microphones? I normally play classical nylon, which of course doesnt work with the magnet based embodiment shown below. I melted the hot glue and ripped out the coil, to use the plastic shell as a pre-made holder for the electret mics to start. The three low strings on this guitar are from a nylon set.

As you may know I am in the final stages of my first ever build (measuring and tuning). In the meantime, I am thinking through the concept for my next project and I am thinking a small 3-way monitor with horizontal orientation, i.e. this layout:





The conceptual requirements are:

• self contained (i.e. electronics i.e. amps, crossovers built in) stereo pair
• as compact as possible: dimensions as small as possible while still fitting the plate amp and drivers
• very good LF extension (this is in conflict with the above)
• SPL low to medium (no high SPL should help the above)
• simple (to make) cabinet. Sealed box.
• cost low to medium (i.e. low to mid tier drivers, MDF as main box material, cheaper electronics if available

Questions:

• what are the options for plate amp and crossovers module? I am only familiar with Hypex FA series and from those it would be either the 123 or 253. They are both 360mm long, which would dictate the minimum size (width). I would like to find similarly featured options cheaper and smaller, if available
• what would be a few driver options for each channel?

For example, if the overall width is 36cm, then a abt 20cm woofer can be (tightly) accommodated, together with a abt 12cm midrange and abt 5-6cm tweeter (typical tweeters with 10-13cm plate would not fit). Woofer chamber will need to be small, which would limit the range of suitable woofers, I suppose.

Hello,

I joined hoping to find a solution to my problem, seen some threads from guys that are very knowledgeable about the circuits and components, figure to give it a shot here and maybe learn a thing or 2.

My B4-X recently stopped working and I've been trying to fix, but I am very new to this kinda thing. The tubes no longer light up or heat up but I'm not sure which part would need replacing or fixing (DC-DC Converter or tube or something else?)
I've done what I can with a multi-meter and seen that the battery is fine, sitting at ~12.5 V. Where would I probe to check the DC-DC converter and the tubes and what should I expect to see? What else might have failed to cause this?

Thankful for any information

Cheers!

I'm a new member here
ヾ(´︶`*)ﾉ♬
(^y^)

Hi Folks!

I would like to turn an AES/EBU Input which I don't need/use



into a Toslink Input. But neither Neutrik nor anyone else seems to have a mechanically compatible product. The electronics after the socket with sensor are less of an issue.

This product would do the job, but does not fit mechanically:


Thanks for your solution suggestions!
Regards,
Winfried

Hi. My name is Ian. I like to work on and build tube amps. I've come to this site many times for help but haven't joined until now. Look forward to chatting with you all.

pls delete post

Nice to meet you all! Been working on some 3d printed speakers which eventually led me here.

Balanced audio technology VK500/1000: "Single-Ended Bridge" Topology, 450W into 4 Ohm

About
http://www.balanced.com/resources/brochures/1998/VK500desc.pdf
I read:
A typical solid-state amplifier
will have four or five gain stages, with a feedback loop traversing these same
stages to correct the signal. The VK-500 uses only two gain stages—without
global feedback. Unusually direct for any amplifier, this purist signal path is even
more surprising in a design of such high power. The ingenuity of the signal
path is complemented by a unique single-ended bridge topology that allows the
use of superior N-channel MOSFETs in both driver and output stages. The
result is a clear, open sound that breathes life into music.
This sounds like a design from Mr. Nelson Pass.
Also the review about
Balanced Audio Technology VK-500 Reviews
and
Product Review
Perhaps a transition from a "ZEN"-topology to a "CSPP" (Circlotron)??
Who knows more about BAT's topology?

I'm trying to gather details on all available stepped attenuators. Anything and everything that's available, off the shelf premade, kits, diy, parts to make one
The obvious choices like DACT, Goldpoint and some others are I'm certain very good, but considering the cost and that I'll need several units over time I'm hoping for a less expensive solution. I was ready to purchase 2 Goldpoint blank units but stopped. Maybe something for under $80USD is possible? Thanks!

1) 24 Steps or more
2) 2 decks
3) If premade 20-25K ohms, 5K Linear, 100K linear for one design
4) I'll accommodate any size

Hello everyone, after 30+ years of my equipment in storage my son has decided to revive it and begin becoming a car audio enthusiest. Hoping to find some information here to help in that journey. Thanks Justin

Been into audio for a long time, but haven't diy'd much yet. Closest thing I've done is build a lyra 8 synth. Looking into doing a headphone amplifier next to power some HE1000se headphones. Also have a pair of rotel rb 1070 amps I'd like to refresh running some vandersteen 2c. Computer programming / math is my background.

Hi all, I am installing some more powerful sub amps in my home set up and I have an interesting 'problem'
To cut a long story short when I earth the chassis I have a GND loop sound the signal GND is NOT connected to the chassis earth and I have double checked. So the chassis each is only a safety earth and not related to 0V signal in any way directly as far as I can measure. The chassis has no connection to the board. Apart from the heat sink and this houses the output transistors in the normal way, no short as far as I can see or any leakeage

Any ideas, it has a relay for soft start but this is only on the Signal out. The transformer has L, N only connections and I have rewired the unit for mains as I have added a 12V fan with power supply (thermally operated) so very clear on all of the mains connections. It works its just the 'GND loop' sound that I want to remove but still want to keep it safe and have the chassis earth

Any ideas ?

CFP really shines at low bias current. My last MOSFET output DIY amp runs too hot as my like. This might be my next one.
The THD in simulation is about -100dB with 10KHz.

mosfets are used in the input stage and the VAS. I find they are just better than BJT in this context.

Hello everyone,
So I'm finally getting round to repairing my tweeters. Will it be a good idea to change the voice coils aswell? If so from whom do you recommend I buy them.

Folks,

Over in the other meta thread we have been discussing the TDA1541.

https://www.diyaudio.com/community/threads/building-the-ultimate-nos-dac-using-tda1541a.79452/

Based on my experiences, various articles and application notes and practical work by a number of peeps we now have a pretty decent understanding of the TDA1541 and what makes it really tick. Much of it is in line with my previous understanding, but where before I had many black boxes I now have a better feel for the internal circuits and the various implications.

---

In short:

1) The TDA1541 needs a syncronised DEM system with correctly sized DEM filter capacitors and a way of feeding the DEM Oscillator pin's that do not cause DEM switching feed trough into the substrate. Empirically 8 X DEM Clocks (352.6/384kHz) offer the best objective performance.

Very low frequency DEM oscillators with big value electrolytic capacitors are an alternative but a bit questionable insofar as it takes hours of the DAC running to get to correct operation and long term stability is highly questionable. In the end both achieve the same fundamental result in different ways.

2) The TDA1541 has significant capacitive feedthrough from the digital inputs into the substrate and from there into the outputs. It is best imagined as a coupling capacitor of ~ 12pF between each digital input and the analogue outputs. 12pF does not sound like much but with MHz bit clock frequencies there is a lot of feedthrough.

Slowing down the edges of the input signals will reduce this. By using "Simultaneous Mode" we can lower the Bit Clock frequency maximally. At 192kHz Sample Rate we only have 3.072MHz Bit clock in this case. It means the edges can be slowed down much more without ill effects on the digital side, compared to I2S mode which typically has 12.288MHz Bit clock at 192kHz.

Existing "SIM" converters unfortunately (almost) all use the fallacious "stopped clock" system, which maximises the clock speed so a lot of clock feedthrough happens for a short duration and then nothing for the rest. This means we cannot slow down BCK edges too much, nor any others. So I will not consider such systems desirable.

There are debates around analogue stages and other TDA1541 related circuitry, but they are not (yet?) part of this project.

---

So, what is the project?

Make a PCB design (open sauce, free as in Free Speech and Free Beer) for a TDA1541(A) frontend that accepts an Amanero standard USB Module, incorporates an SPDIF receiver (optical, Coax and XLR) and includes an IIS to Simultaneous converter that outputs a continuous BCK at 16 X FS and the necessary LE Signal and Data and slew rate and voltage swing limiter circuitry.

Just add a TDA1541 (we might bring the IC position onto the PCB with other bits, this remains to be seen), power and analogue stage (where nobody seems to agree on anything).

As this is DIY Audio, we want to do this in discrete logic, not using CPLD or FPGA or bought in CPLD/FPGA Modules. Why no complex logic? Typically we find a few 100pS P-P additive Jitter from CPLD, FPGA or CPU's (e.g. XMOS). Ground bounce and other problems are significant. The IC cases are distinctly DIY unfriendly, a tool chain and programmer is also needed. It adds up. We can reclock to block a lot of this, but still, why?

---

With an Amanero Footprint (we can add more) the USB input is taken care of. For SPDIF the WM8804/05 series is EOL and others re unclear. So adding a CS8412(14) footprint is probably easiest, we can add suitable adapter PCB's for WM8804, CS8416/DP7416, AK4118 etc. on the PCB.

The main challenge is that we need to take a BCK of 64 X FS and a 2 X 32 Bit Data steam on one data line and output a BCK that is divided by 4 and two Data lines that have 16 Bit Per sample.

There are a number of possible approaches using shift registers, but as we need an input register to hold data from the I2S input (say 8 X 74HC595) and then an output register (say 4 X 74HC165) to hold 16 Bit that go to the TDA1541, this rapidly becomes a logic IC grave. We can find some 16 Bit Shift registers but these still account for a lot of circuitry.

On the plus side, the logic in this case becomes very transparent, obvious and easy to design and debug. Still 16 IC's or so seem a lot to me. It does remain an option.

An alternative would be to use the 74HC(T)40105 FIFO. As we have separate input and output clocks and the "elastic" FIFI we can stuff our 16 Bit into the Input side at the 64 X BCK speed and clock our data out steadily at 16 X BCK and the FIFO takes care of everything.

This would use one 40105 FIFO configured as 64 Bit Delay line with data taps at 16/32/48 and 64 Bit's so we can have the input bit's for our FIFO arrive simultaneously.

Two more 40105 FIFO handle data build as a 32 Bit X 4 FIFO. We stuff bit's into the first FIFO from where the ripple immediately to the output. We then clock out using our 16 X FS BCK. On the input side we invert MSB and only pass actual 16 Data bits, stopped input clock to block off the rest.

I think the FIFO solution is by far more elegant. An option for a secondary PLL with VCXO (or a VCLCXO) can be designed in as well.

A discussion start is here:

https://www.diyaudio.com/community/...ac-using-tda1541a.79452/page-517#post-7939329

So, if anyone wants to join into the discussion and project, feel free.

Thor

Looking for a Bliesma T34B-4 tweeters (pair).

Hello, I repaired by XPS2 as it no longer had enough output to power the turntable motor. As per earlier thread the XPS2 service manual is here:

https://www.vinylengine.com/library/roksan/xps2.shtml

Firstly here are some notes on the circuit diagram as it is a bit sparse. IC 706 is an M706 counter, pin 8 is Vcc (+15V) and pin 5 is GND (0V). IC 324 is an LM324 op-amp, pin 4 is +Vcc (+15V), in 11 is GND (-15V). OP1 and 2 are LM1875T power amp ICs,pin 5 is V+ (+28V) and pin 3 is V- (-28V).

I added some further labels to the circuit diagram as follows. Outputs A (shown as AA by mistake) and C are 90 degree phase, one of these is connected to E and hence OP1. Outputs B and D are 0 degree phase, one of these is connected to F and hence OP2.

The capacitor and resistor on the - input to OP1 are C26 and R7, and that on the - input to OP2 are C25 and R5.

A few years ago I replaced most of the mini electrolytic caps, these are annoyingly small and fail due to overheating. This year a few of them needed replacing again, PSU was still not working. I found that the 33/45 and the Operate/Standby switches were high resistance, Fortunately pressing them many times restored the contacts.

I found that C25 and C26 had both failed being close to the hot LM1875 chips. When replacing them I lifted the opposite end of the corresponding resistors (R5 and R7) and soldered the new caps between the resistor lead and ground, then shorted the old C25 and C26. This left the new caps further away from the hot ICs. I now had outputs from both OP1 and OP2, but the OP1 (90 degree phase) AC output voltage was half that of OP2 (0 degree phase). It was only when I connected a scope that I saw that OP1 output was not a continuous sine wave but rather a series of bursts of sine followed by no signal. Replacing the LM1875T for OP1 restored normal output and the turntable was back in use.

Also note that the 22k ohm resistors between OP1 / OP2 output and - input are SMD parts on the track side of the PCB. I lost one so replaced with a resistor with leads.

Regards,
John

Hello there and thank you for giving me access and any guidance you can provide. I came across a line array design that caught my attention and I would like to make a couple of them to see how it is. It has 1 x 6.5" and 1 x 8" and a driver. It does not say the size and the design does not explain if it is 2 way or 3 way, although I personally understand that the 3 way is more complete.

Does anyone have a source for an assortment of SBM belts?. Just one kit with a bunch of sizes.
"That sight" seems to only have SBS. I need better.

Any ideas?

Thanks

Working on a Kicker KXA2400.1, there doesn't seem to be much info out there on these. Found schematics of the KX (not "A") series, radically different. Powers on, everything looks reasonable, protect light comes on then goes off, draws about an amp once it's stable, no output.

Opening it, found a nice flash mark where a little lockwasher came from somewhere and wandered over to short the positive rail busbar (near the green LED & USB port) to the grounded pressure plate for the rectifiers. The washer was mostly vaporized and the rail is no longer shorted -- the positive rail comes up to voltage fine, but the negative rail is dead.

Also found a blown capacitor in between the two output coils, replaced that, still doesn't work. No other obviously failed components or flash marks from said washer shorting other things before meeting its demise.

Weird power supply architecture, using two non-isolating boost converters instead of the usual transformer. Seems to be asymmetric as well, the positive rail having more transistors and higher voltage rated caps than the negative. And here I thought Rockford was the king of trying to find new ways to patent a switching power supply.

Anyone worked on one of these yet and have any pointers, or perhaps a schematic of it?

Thanks!

Here is a 1990 circa Citronic PPX300 Lateral MOSFET amplifier, made in the UK!. As some will know these PPX amps are very well built and reliable. (The bigger versions have drain fuses on each MOSFETS)

100 watts @ 8 ohms per channel, 500VA transformer, three pairs of lateral MOSFETS per channel, 2x10,000uF filter caps, headphone output via dropping 68ohm large resistors and caps (big ceramic resistors in pic) No relays. DC protection via TRIAC crowbar. Also includes some sort of VI limiting circuit to protect the gates? Looks like there is drain resistors for each MOSFET? Help limit current instead of fuses like the bigger models? Dead silent main outputs and headphone outputs

All seems original. Just going through a little refurbishment. Nearly all capacitors are still in tolerance except for the DC blocking input caps around the level pots. Changed them from 10uf to 100uf for a lower high pass frequency. Changed the feedback DC blocking cap to 470uf. There is a few tantalum caps but they measure spot on.

Bias was a bit hit and miss. The bias pots have an unknown value. On the case of both pots there is melted part, I guess to prevent movement? Little sticker on top to prevent dust ingress. Both pots fell to pieces when I removed them. I tried a 470 ohm pots as a replacement but got very little movement in bias so I tried a much high resistance 5k pots for now. Bias quite sensitive to these high resistance pots. Higher resistance increases bias, lower resistance lowers bias. Set bias at 150ma. The bias transistor gets rather hot though on both sides no matter the bias current. Too hot to touch, approx 50c, TR7/TR17 2n5416 in pic .

There also seems to be a Thermistor (TH1) connected between P and N gate resistors. Anyone know why?

The dropping resistors for the opamp 15v supplies will need replacing, Heat cracking 1.8K I think.

Subjective sound qualities... Bass very good, top end best I have ever heard. Very smooth.

Does anyone have a schematic for the PPX300? I have a schematics for the PPX900 but there is differences and board printed component numbers are different on this 300. Thanks.

Hello,
I'm looking for the spec of this 3 ways project but I cannot find any info, please help. (I already have the box and drivers ready ;-))
Thanks
ADZ

Looking for two B&C Speakers DCX50 for a loudspeaker construction project in our non-profit cultural association.

Willing to pick it up in germany or uk.

Does anyone happen to know the pinout of the 25 way snake socket on an Alesis Surge Electronic Drum Kit? - my old 70's band has got together for another gig, and the drummer has just changed his Alesis DM6 drum module for an Alesis Surge drum module. He only got the module, and is using his DM6 snake lead, which from what I can gather is wired differently to the one for the Surge. I'm doing the PA, so am expected to sort things out! 😀

Basically everything seems to work, other than the Hi-hat Controller, which does absolutely nothing, I've had the controller to pieces, and have just changed the membrane switch inside (just in case - as it's cheaply available from Aliexpress). Unfortunately, I don't have access to the unit, or the lead, to play with - or in particular a Surge so I could test it.

While I say 'everything else' works, all the plugs seem to be plugged in the wrong places, and he's presumably swapped everything over with the controls? - but to be fair, it sounds pretty damn good 😀

Googling finds a bit on info, but none of it sounds very confident, and if I'm going to wire a 25 way plug to socket for an adaptor, I'd like to be confident it's going to work.

Thanks for any helpful suggestions, other than shoot the drummer!!.

I have been developing a new compact stick-on Bluetooth True Wireless Stereo (TWS) amp for passive speakers. It lets you turn any set of passive speakers into an instant streaming solution to have music anywhere in your home, workshop, garage, pool, picnic, etc.


Each amp just needs a local power outlet from the wall or can be battery powered. The amps connect and are paired to each other wirelessly for stereo left and right with a single Bluetooth connection.


The wireless connection to your smartphone, tablet, computer, etc. works instantly and easily for frustration-free Bluetooth 5.0 quality sound. Successful connections are confirmed with a quick tone (no annoying voice) and LED blink from the light pipe indicator at the “eye” of the letter “i” in the word “Link”.


Internally, the Bluetooth RF modules are capable of Bluetooth 5.0 standard (345 kbps max bit rate) and has terrific range and reliability. The Class D amps (TPA3116 based) driven by the Bluetooth RF modules are capable of 50W into 4ohms and 25W into 8ohms, and are wired in parallel bridge tied load (PBTL) so can actually handle 2ohm loads. The amps come with dual 24v 3A desktop universal voltage SMPS modules. Optional low profile 12v 2A wallwart style SMPS (in white) are also available for minimal visual footprint when used along side of decorator furnishings and significant-other-sensitive interior spaces. Even at 12v, 83dB sensitive speakers play plenty loud and clean for most home uses. The sound quality is excellent and the simplicity of it all is fantastic.



Here the Vera-Link is seen attached to the back of the Vanguard speaker:


Here is a nice clean no mess speaker installation in my upstairs bedroom. The white power cables and wallwart blend in very well. All you need are speakers and some stands. You can drive it from your smartphone (which is how most of us listen to music nowadays in my house):


Here is the 24v 3A desktop power supply (two are provided with set):


This is the 12v 2A wallwart power supply (USA and EU plugs available) in white:


The Vera-Link amp kit will sell for $199 a pair complete with 24v 3A power supplies and high quality gold plated banana plugs. The amps come with hook-loop strips with self adhesive for installation to any speaker. 5 unique Vera-Link amp pair Bluetooth names will be available so that you can have multiple sets in one household without confusion.

An early review by Stereo Times is now online:
https://v2.stereotimes.com/post/vera-link-wireless-amplifiers-by-greg-voth/

Also one on Tone Audio magazine:
https://www.tonepublications.com/audiophile-apartment/vera-link-the-most-fun-you-can-have-for-199/

You can order them here:

https://verafiaudiollc.com/

It’s one of those lunchbox size amps, from the 80s. It’s in mint shape with a cover, I played through it with my electric banjo and it sounded awesome. It has multiple inputs and outputs, a graphic EQ and a cool echo/ reverb.

The only problem is, I was testing it outside, so there was a lot of background noise, but if I put my head near it, I could definitely hear white noise. Not hum, or crackling, but smooth, full spectrum background noise- steady volume level with nothing plugged in, pots at any setting.

Once I heard it, I could I notice it from further away. I definitely couldn’t hear it while playing through the amp, but in my quiet apartment, I know it would drive me nutty,

The service manual is linked, but some of the descriptions of the testing I didn’t quite understand. anyway, I’ve replaced capacitors before, even SMD components, and I’m pretty sure I could replace transistors. Only $250, could probably get it for $200

What are the chances I could get that noise floor down, and how?

That’s my question.

here's the service manual/ diagrams, link and pdf.

http://bee.mif.pg.gda.pl/ciasteczko...eger/Gallien-krueger_200MV_Service_Manual.pdf

thanks!

This schematic came up in a conversation on another forum and it intrigued me so much that I drew it up in LTSpice and took it for a spin. It seems to perform vwell. I'm trying to understand the working principle and I think what look like current mirrors are actually working as common base amplifiers. But why? What's the idea behind a design like this? Anyone familiar with it?

Hi to all, finally some news regarding this project. I took up working on the amp and brought it back to life, after some extensive fault-searching. It is now up and running, repaired and mostly overhauled. I am waiting only for the three big capacitor cans (C904, 905, 906). Plus some final work 🙂

Thanks to @Mooly for walking me through the repair of a SONY TA-3650 last year, I would not have made this one without your advice. I am happy I could apply my learning this time! I also posted this message over at Audiokarma, where member rswojo scanned the service manual for me (thanks!)

This thread here is the sequel to an older one where I already announced the SONY: https://www.diyaudio.com/forums/sol...0-amp-2sd46-output-devices-2.html#post6665620

This amp is put together very tightly, so work was a bit difficult at times. It is tedious to unscrew a lot of stuff in order to access some parts: if you want to get to the output devices, you need to unscrew a horizontal bar on the upper side of the four individual heatsinks and unscrew each of them from below (two screws). Then you'll find that all the outputs are soldered into the sockets... Three (SONY 2SD88) of four were shot; the fourth (and intact) one was a SONY TX-183S. So somebody already had tried something. Obviously this transistor type (to my knowledge e.g. found in the SONY TA-3200F) seems to be more rugged. All 4 substituted with MJ15024.

Various resistors in both channels in various places were burned. Some small transistors had visibly exploded. The two unobtainable SONY drivers in each channel had miraculously withstood the damage. After pulling the outputs, replacing the burnt resistors, and a lot of testing of the main amp on a DBT (impossible to do this without) and comparing voltages, five other transistors were substituted.

The emitter resistors of one channel were open, which was invisible, so it took me a while to understand that this was why I could not get bias voltage there. After the repairs there was still intermittent distortion in the left channel, which went away when I poked at the bias pot. This also took some time; I found a nearly invisible broken trace close to the solder joint.

After the repair (better get that done first), I started the recap with mostly Panasonic FC which I like a lot. Slightly enhanced capacitance where possible: I went up from 220uF to 330uF (higher voltage) in the emitter feedback caps of the phono and pre amp, and from 470 to 680uF in the main amp for a lower f3. WIMA films for low value coupling and feedback caps.

As the power supply is intensely regulated (it is nearly the same circuit as the 6200F, missing one transistor, but for the rest very similar), I did not up the capacitances very much (for fear of making the transistors smoke). I put in 1800uF/35V FCs instead of 1000uF/10V at C807/808 in the power supply. The main filters will be those blue United Chemicon cans with 50mm diameter and 10000uF/100V which fit exactly in the space of the old ones. C904 will be substituted by a KEMET 1000uF/200V, which will also exactly fit the clamp (25mm).

I put in new dial lamps (8V fuse type). To access them the faceplate needs to be unscrewed, then you can also recap the pre amp which is fixed to the bass/treble pots. The stereo lamp is not fixed yet (stereo works), and I'll unscrew the dial glass again in order to clean the sides from old lacquer and put on new glass stain; the light is very dim and not very green. Maybe I'll then also change the Mylar input cap of the preamp into a bigger polypropylene which I left out for the moment. I'll also change the 4 pots in the main amp to new ones and will substitute the input cap C701/751 from a 0.22 green Mylar to a 0.47 WIMA MKP4, which I also very much like. So still some work ahead indeed.

There are endless variations of this simple circuit changing the voltage, bias current, and JFET. I'm optimizing here for relatively low Z headphones and overall simplicity.

The gain is 6 dB. Output bias current is 100 mA.

The circuit board is 50mm x 50mm.

Note: the LTSpice output distortion FFT is a little misleading as the JFET and MOSFET 2nd harmonic tend to cancel and how much cancellation depends on the headphone load and output signal. I just happened to hit a minimum at the simulation conditions shown. Typically it's about 0.2 % at -20 dB output.

I have for sale custom made aluminium enclosure for D class amplifier. Front plate is made from 10 mm aluminium, side plates from 12 mm aluminium, other plates from 3 mm aluminium. All 10/12 mm plates are CNC machined. Enclosure has extremely fine black power coated finish, so it quite resistant on finger marks. Enclosure comes with blu illuminated LED latching button, set (4x) of quality speaker terminals and main power switch/IEC inlet. Outer dimension are: 380x286x90 mm (feet and speaker terminals included). Inner dimensions are: 333x263x75 mm. Weight is around 4kg. Amplifier enclosure is suitable for 3e amplifiers (holes already drilled) and others too (Purifi Hypex), with some modifications of coarse.

Price is 175 EUR + PP fee + post costs

If you have a pair to part with…

Hi, I'm restoring a couple of Quad 2 monoblocks. The amps worked a long time ago and I have replaced all the rsistors with Kiwames, the main psu caps with F and T 15 + 15uf caps and the other electrolytics with decent quality Nichicons. Coupling caps have also been replaced. On turning on the amps the rectifier and output tubes all flash as if the amp is oscillating wildly. The cathode resistor (5 watt) is getting very hot quickly so the tubes are dissipating much more than they should. Both monoblocks are behaving identically so it cannot be a case of a poor /missed connection. I tried adding two x 22pf caps to the grids of the output tubes which made no difference. So my questions are:

1. Any pointers on the cause given these amps are generally stable?
2. Any pointers on the best way to test given I don't want to have the amp operating with this level of excess dissipation?

Thanks in advance
David

I am thinking about creating a tutorial for a wireless DSP-capable DAC based on a Pi (3/4/5) and a HiFiBerry HAT. I wanted to get some feedback to see how much interest there would be in this kind of project/tutorial.

The idea is to be able to have a DAC that is fully DSP capable but is not directly connected to another computer. Audio is sent from a computer running Linux or WSL2 under Windows 11 over the LAN (wired or wireless) to the Pi, where any DSP is carried out and then the audio is rendered via the HiFiBerry HAT. Audio is streamed as uncompressed PCM in a fixed rate and format of the user's choosing.

I am currently working up this concept with a DAC8x HAT and I wanted to see how much interest there would be in a tutorial. Other audio HATs for the Pi by HiFiBerry can be used, or even USB audio interfaces, etc. using the same approach and only small modifications to the setup. The audio quality is primarily determined by the DAC itself, and the user is able to change that at will.

Hi All,

I have noticed that when the volume is tuned down with no sound that the left Vu meter on my Luxman M03 is showing a reading of (0.01) and the right is (0.00). There are no issue with sound etc and the Vu eventually went back to (0.00) after a short listening period. I have however noticed after starting up again a while after that the left VU is reading (0.01) again.

Any ideas on what could be causing this.

Thanks in advance.

So I've been on the lookout for an affordable, small diaphragm/body omni mic for room measurements. Something that will be be more omni to a higher frequency than a 1/2" mic body. I've had my eye on the MicW M416 for that purpose for some time, but last month I saw that Behringer sells a new measurement mic that looked like it would fit what I was looking for so I took a chance and ordered one.

It's called the ECM PRO, and it's clearly "inspired" by the DPA 4091, or Neumann MA 1. But as of this writing, it is only about $40. There is a calibration file that you can download for it that is highly suspect. I tested it out against one of my calibrated ECM8000's with a tweeter in a low(ish) diffraction cabinet, IR windowed, and trying to get the diaphragms in close to the same point in space.

Here is on axis ECM PRO uncalibrated and ECM8000 calibrated:

Here is ECM PRO 0 degrees to source and 90 degrees to source:

And for comparison, that ECM8000 also at 0 and 90:

I haven't tested it at low frequency yet, but the ECM PRO is as expected, more omni than a ECM8000. Unexpectedly, however, this particular one needs only minimal calibration.

Hi all.

If you don't know about the Rush cascode I suggest you use Google and your other preferred resources to get some background information. Here are some threads and pages where it has been discussed:

http://www.4qdtec.com/pwramp.html

http://www.4qdtec.com/preamp.html

http://www.diyaudio.com/forums/showthread.php?threadid=61289

First of all, I need to add that I don't have much experience in electronic design. My comprehension and understanding at this point has come entirely from resources such as DIYAudio, Doug Self's site and many other free internet resources. Even though comprehension has come relatively easy for me, everything I know has still come from theoretical sources and not true time-tempered experience.

The Rush Cascode is a manifestation of the differential long-tailed pair. Same concept, different ways to implement it. It was first used by englishman Christopher Rush of THX fame, who is still designing today (info provided by AKSA).

In some posts here on DIYAudio, the Rush cascode has been dismissed quickly after theoretical and mental comparisons to the conventional long-tailed pair (henceforth referred to as the LTP) as an input scheme. I think more thought and work should be put into its understanding.

The Rush cascode can be difficult to get working because of its speed and gain, not to mention DC offset and temperature compensation if one intends to make a DC-coupled amplifier. However, there are things we can do to get around this, which I intend to expand upon.

The rush cascode can be difficult to make stable for the following reasons:

1: High gain.

2: High speed.


The common solutions to this are:

1: A degeneration resistor between the emitters to decrease gain.


Firstly, it seems there is a misconception that like the conventional LTP, the Rush Cascode benefits from using high-gain transistors. In my simulations I have found this to be inaccurate.

I have the following observations to present:

1: The distortion of the Rush Cascode is more dependent on the degeneration resistor than it is the transistors used. A low degeneration resistor will in my experience get lower distortion.

2: Stability decreases with higher-gain transistors.

I have the following suggestions when implementing the Rush Cascode:

1: Use low-gain devices, like the 2N5771/5769, with as small a degeneration resistor as possible.

2: Increase open-loop gain in other parts of the circuit instead of the cascode itself. This will result in better stability and distortion than the other way around.

3: Use both legs, rather than one, to increase OLG and VAS speed.

I believe that the Rush Cascode should have some 'net coverage, which is why I am doing this. More people should know about it.

So I want to make a Wiki page and/or PDF that talks about it along with some example circuits. I also have designed and amp on the sim that has a nifty thermal and DC offset compensation scheme, although it requires some calculations.

I want to see more circuits with it, and I want to see how others get past its shortcomings.

Attached are some ways I have used it in the simulator.

- keantoken

Simulation of a BTL 4x4 LM3886 amp with protection.

For performing any modification steps I want to have the genuine circuit diagrams. Maybe one of the member can upload this.
in post #51 under
https://www.diyaudio.com/community/threads/2sj49-2sk134.1188/page-3
is mentioned, that one of the most used circuits was choice for the power amp.
This URL in German I have found concerning this models
http://www.hifi-forum.de/viewthread-84-24940.html

Hi Everyone,

Earlier this year, I was fortunate enough to purchase an original 1996 vintage Aleph 5 amplifier. It was described as being in working condition, but since it was located in another city, I couldn’t test or inspect it in person. I only recently got my hands on it.

When the amp arrived, it was freezing cold, so I knew it wasn’t safe to power it on immediately. In my excitement, I decided to take a peek under the hood, which led me to remove the side heat sinks so I could get the top off. Since I’d already planned to replace the original, aging capacitors, I decided to proceed with the upgrades.

I replaced the original Pani 220uF capacitors with Silmics, adding 1uF Wima bypasses, and I swapped out the four original 33,000uF cans for new 47,000uF ones.

At this stage, I noticed something concerning: the fuse holder showed signs of excessive wear, and instead of the factory-specified 4A slow-blow fuse, a 6A slow-blow fuse was installed. It dawned on me that I might have made a rookie mistake—modifying the amp before confirming that it was actually functioning. With that realization, I reassembled everything, triple-checked all the connections and capacitor orientations, and prepared to test the amp. For what it’s worth, I didn’t see any signs of damaged components or previous repairs inside.

For testing, I powered the amp using a dim bulb tester with a 100W bulb and connected a pair of multimeters to monitor the DC offset at the speaker outputs. I understand that a class A amplifier will typically keep the bulb brighter than a standard amp, making it harder to interpret the results.

On powering up, the bulb initially went bright, briefly dimmed, and then brightened again. The real concern was the multimeters showing large amounts of DC at the outputs, prompting me to immediately shut everything down. I wasn’t able to catch the exact peak DC values because of the quick shutdown, but as the power supply discharged, the meters both showed around 1V DC for an extended period.

This brings me to the part where I’d appreciate some guidance. I’m thinking of disconnecting the output stages from the main board to isolate the issue. This would let me test the power supply voltages and determine whether the front end is feeding DC to the outputs, helping narrow down which section of the amp is causing the problem.

Does this troubleshooting approach sound reasonable? Or is there a chance that my testing process itself was flawed?

Thanks in advance for your advice!

Hello all,

I'm in the midst of tweaking my 3-way crossover and I could use some help. My drivers are an Eminence Alpha 15 woofer, a Mark Audio Alpair 12P midrange and a GRS PT2522 planar tweeter. They are in an open baffle. Here is what I have





I realize having the resistor in series on the woofer is not ideal.

I only had frd and zma files for the GRS but here's the frequency response graph on x-sim





and here's the measured in-room response:




as you can see, there's a dip in the mid-range.

Things I'm thinking of doing:

changing the 68uF cap to the woofer to 33uF to smooth the spike at 250K. Change the 1.1uF cap on the LP filter section on the midrange to 5uF. Increase the values of the resistors on my tweeter L pad.

I tried an L pad on the woofer and it sounded terrible. I didn't have a bunch of values of resistors available for use however. I tried resistors in the 2-3ohm range. What would you recommend to attenuate the bass?

As is, the speakers sound pretty good but I'd love to get them more balanced

thanks!

Hi all,
for sale Edifier MR4 studio monitors. As these measured well with respect to linear frequency response, I bought it to check recording quality of hindi film/classical music. The purpose is served and the same are for sale. Pictures were for Indian website so I had to put name and date.

• Like new condition. Just 2 months old. And not used much. Just tested 35 to 40 titles of Hindi film/classical music cds songs for ~20/30 seconds.
• Another reason for sale is need funds for a new DIY project.
• Probably has carry in warranty still left for 9/10 months. (Service center India : LINK )
• Original Bill, box, cables and literature etc. available.
• Sound quality is good with just enough bass .
• Tone controls with neutral position.
• Headphone, Aux, TRS and RCA inputs.
• Video of working and sound test available.
• This will probably be for India sale only. Or if anyone is visiting India.
• If any question ask.

Price is Indian Rs. 9000/- (significantly lower than original price). Shipping Extra at buyers risk.











Thanks and regards.

Hi All, Recently get mauthe clock from my grandfather and fix it. Nice to see you all

Hello retro fans!

I visited local Red Cross flea market and bought a nice vintage art deco-style Mauthe mantel clock, sold in 1965.

The box's oak veneer coating had some erosion, but Osmo furniture wax fixed them easily. Mechanism is labelled W45 XXVI sno 97199
The mechanism is working and it has three bells but seems to not ring on right hour count. Any ideas before I show it to local watchsmith?

Next project. What to do with the high quality drivers one already owns. Left overs from projects that changed or never was.




Drivers are:

2 x Beyma TPL-150/B: https://www.beyma.com/speakers/Fichas_Tecnicas/beyma-speakers-data-sheet-amt-TPL150B.pdf

4 x Jantzen JA-8008 HMQ: https://jantzen-audio.com/wp-content/uploads/060-0008-1.pdf

2 x Beyma 18PWB1000Fe/S: https://www.beyma.com/speakers/Fich...data-sheet-low-mid-frequency-18PWB1000FeS.pdf

Since I already have Infinite Baffle subs in both my home theater (2 x 18") and my 2 channel setup (4 x 21") in the living room, why not also have it in the upstairs office?
Also, I've always been curious in finding out more about Open Baffle. All the superlatives I read about OB seem to fit my ideas of how music could sound in a room.

The idea:

Room is W3,1 x D4,6 x H2,4 m (ab. 10 x 15 x 8 ft) with slanted ceilings in the width direction. Wall height below is 1,2 m (4 ft).

Put the 18's in thick panels, one left & one right, and attach them to the studs (cc 0,6 m (2 ft)) on the 1,2 m wall. Wall panels are too flimsy to be used as is.
There's a space behind the wall that is big enough for the IB to work. Use them up to 100 Hz.

Build smallish (?) baffles for the 8" and AMT's in a D'Appolito and hang them from the ceiling about 1,5 m (5 ft) in front of the wall where the 18's are mounted.
Open the AMT's back and play dipole. X-over 1500 - 1800 Hz.

Use a MiniDSP Flex8 to do the crossovers, DSP and Dirac. (Already have this also)

Buy some class D amps to power each channel.
Maybe IcePower: https://www.soundimports.eu/en/icep...OlLo3S6XKRe-XzumApw7YwO4ijBXg34UaAkgAEALw_wcB
With power supply: https://www.soundimports.eu/en/icep...OlLo3S6XKRe-XzumApw7YwO4ijBXg34UaAkgAEALw_wcB

Maybe a Wiim as source to play music from Tidal: https://www.wiimhome.com/wiimultra/overview

Questions:

- Is my small room suitable for this idea?

- What width should the baffle be to be able to get output down towards 100 Hz from the 8's?

- Do I maybe have to buy some bigger drivers also to help the 8's to get down to 100 Hz, in a WMTMW?

- If I raise X-over to 150 hz, maybe that will help? Or is that too high for the IB?

These are my thoughts so far and now I would like to hear from you, the people with much more experience in OB. I'm a noob.
Is this idea at all feasible?

I have been an audiophile since my youth. First good diy speakers were Wharfedale Unit 5 three ways. Great with my Lenco L78 and Goodmans 110 receiver. Progressed through various speaker builds. A nice one was a Proac R2.5 clone but my favourite so far is a Falcon kit for my T27/B110 Kefs from the seventies with a matched to serial numbers crossover. Also done some amp building , SunAudio 300B and SunAudio pre amp, as well as OTLs from Bruce Rozenblit.

ok so i need some direction as to a 1.4" compression driver. I am looking for a 1.4" compression driver for a 800Hz horn. Budget is $400 each. So far I have looked at:

Beyma CP755/Nd (a little over budget)
Faital Pro HF140 or HF146/r line
RCF ND940
SB Audience 65CDN-T
Beyma TPL150 - Not a compression driver but could look at as I would save $ not building a 800Hz horn
B&C 980TN
B&C 1090TN

I probably have missed a bunch also.

This is for a hi-fi speaker not a P.A. system. For now its just a 2-way with a 15" but may add a supertweeter at a later date.

Thanks for any help!

Hi,

Looking for chassis that are similar to what's being sold here in the store. Mostly interested in 4U and 5U and compatible with F4, F5, F5T, F6, Aleph J...

I'm in Canada (Toronto) so preferably something that can be ordered from a Canadian vendor to avoid import duties and costly shipping.

Any clue where to look for these? Any help is greatly appreciated!

Thanks! Cheers!

I was given a Mc2105 that was dead and heading for the scrap yard. I decided to fix it and 2 years later I have climbed the learning (designed new power boards in KiCad) curve and have it running. I am now ready to build a new amp .

Greetings I am a new member. I am very interested in repairing electronics. I’ve done a lot of it by myself already. I am 59 years old, and I have enjoyed taking things apart and trying to fix them pretty much my whole life, often using using online schematics and service manuals. It’s very gratifying. I am also a musician currently experimenting with electronic banjo. I chose a name for my last musical project, Shad Dart, because it is a fishing lure for catching shad. Where I live by the Delaware River, they swim up river to spawn . The interesting thing is when they’re coming up river they are not eating anything, but for some reason they can’t resist biting on the shad dart. The predominant theory is that the little prickly tail of the lure tickles their nose as they are swimming upstream, and it annoys them or maybe they bite it out of curiosity. Anyway, I feel like it describes my interest in music and electronics and repairing things, something just gets in my face, and I can’t help myself I have to bite on it

Paul

Since my miniDSP SHD has been such a turd as a streamer I thought I would move my 2020 Mac M1 Mini to streamer duties (panic bought an M4 Mini and decked it out for my main computer). I had been using a 13 year old MacBook Pro but I liked the ability to tuck the Mini away.

Anyway, the MacBook pro was fine. I've done lots of measurements with it over the years using a UMik and REW. I've more recently been using a Microsoft Surface since the MBP wasn't capable of running the most recent versions of REW. Annoyingly, the Mini no longer supports optical so I switched over to USB between the computer and the SHD.

Sorry for the long build up, but here's where things get strange. I could easily tell that songs played via the Mini lacked bass. So I broke out the UMik and did some measurements with the Mini. Sure enough, looks like there's a 50hz high pass filter. I hooked up an external sound card that has optical out and I got the same result.

Just to be clear, I was running REW from the Mini. USB to the SHD or an external USB sound card with optional to the SHD both appear to have a 50hz HP high pass. The external sound card is good. The UMik is good. And the SHD (while a crummy streamer) is good.

I then broke out the Surface again and measured and things were back to normal; 50hz down to my high pass protection for the horn sub was back. The difference is clearly audible (I have a Lil Mike horn sub).

Any idea what's going on?

Hi all,

I'm very green to the idea of a PC based DSP. I currently run a MiniDSP HD2x4 but if you've seen what they're doing due to tariffs, it's crazy priced now to the point of extinction. Most other commercial options don't seem to come clone to this, REW importing, filtering to 10hz, etc. All this is pretty big for me as I use this for a large subwoofer network (16 of them). I'm looking to expand and instead getting more MiniDSP I'm looking to see if I can just do it myself with a PC instead. I've searched a bit, seeing Hifiberry, CamillaDSP, etc. But I'm not sure what would be ideal for my purpose. I went to YouTube thinking there would be videos on these to showcase their use, but sadly, didn't see much.

I'm looking to do a PC based DSP that is fairly easy to setup with the context of just doing typical delay, phase, EQ with several channels of subwoofers. Ideally able to filter down to 10hz or lower. I really appreciate features like importing REW, infrasonic filters and a good compressor or limiter. Those are most important to me. I've never built one or know what all goes into it. I'm happy to build a PC for it, or get a little PC or Pi or whatever. It's mostly to explore DIY and have something modular that I can scale to larger amounts of outputs.

Any suggestions for hardware and software for this is greatly appreciated!

Very best,

This is an idea which has been noodling about in my head for some time. A small portable active speaker, of modest cost. Something I can easily build multiple copies of, something I can give as a gift if I choose. I have friends who are decent woodworkers who have inquired about making a copy of one of my existing speakers, but they have balked at the expensive drivers and electronics I use… so this is something I can point to and say “you can copy this…”

I also like the idea of an expandable speaker where a second woofer cabinet can be added to extend the bass response and give higher SPL capability. I got this idea from the Barefoot Sound, where several of their very fine monitor speakers are expandable in this way.

========== =============

Primary Goals

The finished system shall be a compact, active, 3-way with 8” woofer, with a total internal volume of 16-24 liters, with sealed box bass alignment. Update: 10" woofer in a 25 liter volume.

Performance Goals

• Bass response F3 = 40 Hz.
• On axis within target response +/- 1.5 dB from 100 hz – 16 kHz.
• Directivity Index within target response +/- 1.5 dB from 500 Hz – 10 kHz
• No specific max SPL goal or harmonic distortion goal, other than these performance attributes shall be optimized to the extent possible given the drivers selected and the other requirements.

Secondary Goals

• Low driver cost and low electronics cost. At this point, “low cost” is not really defined, but low driver costs would be in comparison to Scanspeak Revelator, Satori, Bliesma, Purifi, etc. I was thinking on the order of $250 of drivers per side, but this is flexible. In terms of electronics, “low cost” means significantly less than a Hypex FA-123 ($550 per side).
• Easily replicable. This means easily built with readily available parts. I may want to make multiple copies to give as gifts.
• Simple cabinet finishing that does not require weeks of shaping, sanding, veneering, sanding, varnishing, polishing, etc.
• Easily portable.
• A modular design which would allow me to design/fabricate a second bass driver/cabinet later. This would extend the bass response and expand the SPL capability. Update: Modular design is no longer needed with the change from 8" to 10" woofer.
• An opportunity to try new techniques and learn new skills which can be applied to my future high end projects.
• An opportunity to discover new information which would be of use to other DIY speaker builders and developers.

What are the electronics options? One option I have been curious about is the line of equipment from MiniDSP. The Flex and Flex-8 are both serious high performance gear. I might use the Flex-8 on a future project. The cost of the Flex-8 (or a pair of Flex’s) pushes the cost into the same range as Hypex Fusion, so this is not appropriate for this project. However, a good stepping stone into the world of MiniDSP software/hardware is the 2x4HD. It has lower performance than the Flex, which is also a 2-in/4-out device at double the cost. But the 2x4HD is good enough for this project. Another compelling reason for me to work with the MiniDSP 2x4HD is that it would be a good development tool for any future project, allowing me to have a DSP in the loop when I develop prototypes.

A single 2x4HD shared between two speakers will not provide the necessary 6 channels of signal required by a pair of 3-way speakers. But a single 2x4HD could be used in an active/passive speaker. This is something that has interested me for some time. A passive crossover from tweeter to mid, then active crossover from mid to woofer. There would be 2 amplifier channels required. I find the challenge of this architecture intriguing.

The interesting thing about this approach is that the passive crossover does not need to perform any EQ of the drivers within their individual pass band, nor does it need to manage the overall EQ or voicing of the speaker. This can all be done by DSP. The DSP can also provide BSC for the woofer channel and the mid/tweeter channel. The DSP can tailor the bass response of the woofer. The passive network will need to provide a high-pass and low-pass function for each driver, and relative level matching between tweeter and mid. The passive network will manage the relative magnitude and phase of the drivers through the crossover, and as a result of this, it will manage the directivity index.

The passive network will also manage any out-of-passband EQ. The most likely need for this would be a notch filter on the woofer or midrange at a frequency above the low-pass filter. For example, if the midrange passively crosses to the tweeter at 3k, but the mid has a + 9 dB breakup peak at 8k, the DSP will not be useful in managing that peak. Any EQ at 8k would affect the tweeter response, which would be quite unfortunate. Thus the passive network will need to handle that.

So at this point, I believe this is how I will proceed. There are a lot of amplifier options which offer low cost and acceptable performance, so this remains an open decision.

j.

================== Update 2/01/2024 =================

Index to important posts or milestones
post numbers are included with links

Decision to use a 10” woofer 119
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7447588

Process of defining cabinet dimensions 132
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7449092

Simulating flat face tweeter vs tweeter with waveguide 124 135 164
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7448383
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7449284
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7450834

Concept sketch 197 236
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7452598
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7455272

Decision to use SB15NBAC 236
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7455272

Electronics block diagram 280
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7457445

Prototype testing of tweeters 289 314
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7457716
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7472903
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7471898

Simulations with prototype data to define mid/tweeter spacing 344 351
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7482295
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7482756

Cabinet construction photos 413 452
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7514053
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7522584

Structural bracing and damping strategy 429 439 442
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7517669
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7518089
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7518208

Cutting tapered bevels 466 467
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7526218

Cabinet assessment – looking for resonances 503
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7539527

Driver polar responses measured in finished cabinet 506
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7539853

Final passive crossover design, and system level polar response and Power&DI 583 605
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7558072
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7567335

Frequency response of Class D amplifiers 613 627 634
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7570120
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7570523
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7575669

Documentation
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7586028

Hello!
I'm new to DIY audio, and happy to learn.
Be ready for some basic questions! 🙂

I have an original ST-35 from the 1960s and a Dynakit version I built in 2012. All was going well. The old one is in storage and the Dynakit is the daily use. Upon power up the Dynakit one went quiet. I could see one tube was out. I decided to check out the reason (besides 13 year old tubes). Upon opening it up I see a burnt resistor. I was an early adopter of the EFB modification. I made my own board for it, but I no longer have those plans. The 100 Ohm resistor used across the tube pins 8 and 9 was fried for the dead tube. By the way, I have the 2012 version of the Audio Regenesis PC-13 boards in the amp. This is basically my issue - I can't find the original plans covering the EFB mod, the resistor was fried. I don't remember how to check this thing out or how to set the EFB bias pot.

I bought some new 100 Ohm 0.5W 1% resistors to replace the four used in the original EFB mod at each tube. I turned it back on and the tube is still toast (dimly lit and no heat generation). No sound comes out of either side. I also have a matched set of replacement tubes, but I do not want to put them in if I have another issue. Everything else looks fine visually.

A couple of observations:

I see on the one schematic I found of the old EFB mod that there is a 5 Ohm resistor between pins 3 of the tubes on each side. I see TP on either side of those resistors. I suspect that the bias is to be measured there and then adjusted. I do not have 5 Ohm resistors there, just a wire connecting the two pin 3s. Were the 5 Ohm resistors a temporary install to set bias or were they to remain?

Where else should I troubleshoot? Any help is greatly appreciated - I miss the sound. I am using the 1960s one now, but am a little concerned by its age and lack of use.

SOLD
One set of complete and tested Miro AD1862 DAC with York + Reclock board (USB-I2S interface)
In my opinion, this is the most direct and best combo for the gem, AD1862.
Sounds wonderful. It is a full, completed DAC kit, equipped with a pair of AD1862N DAC chips and a pair of Signetics NE5534 op amp is included on board the IV stage.
Play with your own op amp to choose your flavor after that, although i can say that the NE5534 is an enjoyable result.

You need the following PSU:
1. +5/-5V (VD),
2. +12/-12V (VA) directly to the DAC board

The York board's 'dirty side' is configured to be powered by the USB Bus ie. drawing +5V from your USB source. This can be changed to be powered from a PSU of your choice if you wish. Can be done very easily by opening a solder bridge on the York board as instructed by the user guide, and then soldering two wires from pads available on the DAC board out to the PSU. The XO and reclock circuit of the York is drawing +5V (digital supply) from the DAC board when you stacked and isolation from the USB 'dirty side' is achieved. Very neat and clean design. The York's reclocker board has been upgraded with AS318B Accusilicon XO.

With the exception of the op amps which are old and used, all others parts used are bought brand new, including the AD1862N chips, for the purpose of putting up the DAC.
All caps are high quality ones including Nichicon gold, Elna Tonerex, Panasonic FM etc.

I am asking Singdollars 430 (approximately USD$330) for this DAC , and i will cover the worldwide registered shipping with tracking available.
I am only ready to accept Paypal Family and Friends as payment.
I have shipped 60+ packages to US, UK , asia and Europe, not a single glitch so far.

More information of this DAC here :
https://www.diyaudio.com/community/threads/dac-ad1862-almost-tht-i2s-input-nos-r-2r.354078/
https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-128#post-6836256

I am currently finishing a build of the 24V 6GM8 / ECC86 Broskie Aikido line stage amplifier and the space I have in the chassis is very minimal.

Is there a simple way to modify the standard circuit to allow for headphone use? For example, can we increase the value of the output caps (C3) to ensure the frequency response for headphones is adequate?

Hi everyone.

As I mentioned in my introduction post, I recently built two wireless speakers. Both sound great overall, but there's one major issue: port noise, especially from the subwoofer.
I built the subwoofer using a GRS 8SW-4HE-8 8" driver. I settled on a box volume of 40L, excluding port and woofer displacement. I chose a tuning frequency of 26Hz. The transfer function magnitude and SPL curve for this particular configuration looked quite good:





For the port, I went with a 12 by 5 centimeter rectangular port. At a tuning frequency of 26Hz, this port has to be 60cm long. To accomplish this, I had to bend the port once inside of the enclosure. I also added an angle to turn the 90° bend into two 45° ones. Here's a rough sketch of how it looks like from the side:


I accounted for all wood thicknesses during construction to make sure the port length was accurate. The internal length of the port came out to be exactly 60cm, just as planned.

In WinISD, the simulated peak port velocity looked perfectly acceptable for this size and power level. At 90W input, the velocity peaks at around 18.5 m/s at 24Hz, which is already below the tuning frequency of 26Hz, so I didn’t expect any major issues with port noise.



Despite the promising results in WinISD, there are two major issues in practice:

1. It doesn't seem to produce much sound at 26Hz. Audible output really starts around 32–34Hz when sitting directly in front of it, not the 26Hz I was aiming for.
2. Port chuffing is excessive. From ~25Hz to ~40Hz, the port noise becomes very noticeable. At times, it seems louder than the speaker itself.
   
   I’ve attached a video showing the port noise when playing a 28Hz sine wave for reference.

Now my questions are:
Where did I go wrong?
Do I have to simply flare the port?
Why else is there so much port noise?

Over the years of Tube Amp repairs, and old instrumentation restorations, I have always relied on an incandescent bulb current limiter, in conjunction with a Variac. I finally decided to build a piece of kit to make this cleaner, and add a much needed isolation transformer.

It consists of two circuit boards, a Relay controller (no software, just good old logic), and a Lamp board. It contains a large 1000VA toroidal isolation transformer for isolation. There are three duplex AC receptacles on the rear panel that are not isolated, one being a 20A GFCI. The other two are switched on/off by the front panel. There are two ground isolated duplex AC Receptacles on the front panel. One is directly connected to the Isolation secondary, the other is bulb filament current limited by selectable incandescent bulbs controlled by relays. The bulbs are visible through the front panel making it easy to see if any current limiting is taking place. There is an input and output for connecting a Variac to use in conjunction with the current limiting section. The Variac input and output is also isolated from the mains.

Since the transformer had low voltage windings, I rectified and filtered them to provide fixed DC of around ±24V. I just hate wasting windings. The variac is also connected to a pair of Banana Jacks in case I need an variable AC source.

There is a Chinese made Power meter that monitors the isolated outputs.

The build was fairly flawless. I handplaced the SMD parts using a solderpaste stencil, and reflowed them in a modified toaster oven. Everything soldered fine, but I had a couple of bridges on a TSSOP part that I had to clear. The LEDs are too bright at only 5mA, so I might go back and change all the LED resistors. I used RGB LEDs for all of them, and pinned out all three LEDs. I could make any color based on which resistors I placed. I mixed some colors by using more than 1 resistor on them. The LEDs are Right Angle Light Piped to the front panel.

The Lamp Board uses E17 sockets for the incandescent bulbs. I designed this with 20W and 40W E17 bulbs which will not be discontinued as they are oven light bulbs which are exempt from being discontinued. I did discover that a 40W bulb really only draws 32W bulb at 120V which kind of threw my nomenclature into error. However, I was able to kludge in "Calibration" bulbs to get it closer to the desired levels. You can see the kludged bulbs on the back of the lamp board in the open top picture attached. I added a 40W (really 32W) to the 160W bank which then totaled actually 160W. I added a 15W E17 to the 80W bank (two "40"W bulbs) which then actually totaled 79W. I'm going to live with the 40W setting being 32W. The 20W actually was darn close when I used a 25W bulb there. I should have anticipated that 40W bulbs are 20% low. This is consistant no matter what brand I tried. I think I will make a modification to allow an external lamp to be put in parallel for higher powered applications, but so far, it has plenty of power for what I'm doing.

The final build had a lot of wiring to hook up. Mostly wired with 14AWG Elastomeric Insulated hookup wire. I used ferrules in all the terminal block wiring. I used lever Terminal Blocks from WAGO. The picture showing the open top was before I dressed the wiring up neater. There is a lot of wiring in there!

The enclosure panels were supplied by the excellent SENDCUTSEND company and were laser cut. Front, top, and bottom panels are 100mil Aluminum, and the rear panel is 70mil aluminum (because some of the press-fit connectors I used on the back would not work in 100mils). The Front panel is powder coated, also by SENDCUTSEND. I brushed the other panels. The side panels are heat sinks provided by HeatSinksUSA. They are extrusions that are thick enough at their base to drill and tap all the holes that hold the whole thing together. I didn't really need heat sinks, but they were readily available in the size I needed. The price for doing all the aluminum was surprisingly low, and far more accurate than I could manage with drill press, not to mention I have no good way of cutting thick aluminum panels.

The labeling on the front and rear panels is Vinyl originally designed for transfers to things like cups or fabric. But it allows full color, quite detailed nomenclature. I'm really happy how that turned out and it seems quite durable. The labeling was made by Ninjatransfers with their UV DTF Gang Sheet product. I suppied art from Adobe Illustrator.

I have spare circuit boards. If anyone wants to make one (for private use only), I am willing to share all the files for the enclosures, and I have left over raw PCBs.

I have a pair of brand new never installed T34B tweeters. I do not think these need any introductions as they are just amazing 🙂. Price is $1000/pair shipper in the US and PP-fees are included. Sorry US sales only. Thanks for looking.

Im looking at building this Class AB1 cathode biased amplifier based on this design here.
I have most of the components on hand, including a suitable power transformer and pair of OT's.
I am making a few changes, I am using an EF37A/6J7G instead of an EF86 and using 807 tubes instead of 6L6.

Few questions, is the 750pF capacitor across the CT to anode on the tube to remove oscillations? I find its odd only one half has this, ive never seen this before on such a schematic.
There is also an 820pf cap going across for the NFB loop, how critical are the values for these capacitors?
I have quite a bunch of silver mica caps on hand but nothing quite exact, ive got a few 680pF and 1000pF on hand if they will suffice.

Here is the schematic and a rough layout ive drawn of the turret board.
Another issue im unsure will be a problem is i mirrored the layout, so have to cross some wires over, not too sure if this is a worry, you will see what I mean with the channel on the left of the image.
The phase inverter was not too big of a deal, as i just swapped over each triode section.
Im unsure about the path of the heater wiring, but its just rough, I will probably move the tube sockets around some more and I have not included the power supply yet, but all the transformers will sit behind the 807 tubes at the bottom of the image. The filter choke im hoping will fit under the chassis.

Looking for a Purifi PTT6.5X04-NAA-08 drivers (pair)

Looking for a Purifi PTT8.0X04-NAB-01 or Purifi PTT8.0X04-NAB-02 (pair)

Looking for Hypex Nilai500DIY

Hi, after the request of @OldHector , I post here my own version of the Baby Huey with EL34 (that fits well with KT77 and other tubes).
I will also post some guidelines for other tubes like 6550 (I would avoid KT88 because the original pcbs have the sockets too close for KT88).

Let's start with a bit of hystory: this kind of amps have ultralinear and Schade feedback combined.

Schade original feedback (1938) can be found here:
https://www.dos4ever.com/uTracer3/Schade.pdf

Crowhurst reposted that kind of anote-anode feedback in 1952 here:
http://www.tubebooks.org/Books/Crowhurst - Audio Handbook No2 - Feedback 1952.pdf

Yves Monmagnon posted the PP Schade feedback (and phase inverter supply) in pentode configuration plus conventional gnfb here:
http://www.dissident-audio.com/PP_ECL86/Page.html

The EL84 development has been done in 2006 by @gingertube here using 40%UL and Schade feedback:

The EL34 version has been started by bandol (RIP) in 2018 here with 40% UL and Schade feedback:

Here I posted a similar thread with noted on the EL84 version:

Here I will report my takes on the EL34 version, but before a small introduction on Schade feedback:
Numerous tests have been done during the last 90 years, but just to report real measurements, I link some sources:

One is Broskie in 2001:

https://www.tubecad.com/march2001/


One is Bertola with his plts on Schade feedback only.
in 2013 he has tested on the curve tracer the 807a ( https://frank.pocnet.net/sheets/136/3/307A.pdf ) showing how Schade alone can triodify the curves:

source: https://www.bartola.co.uk/valves/2013/03/16/307a-dht-in-triode-and-schade-feedback/#more-1331

Some italians have done tests on the curve tracers too in 2021:

source: https://www.sb-lab.eu/schadeode-alternativa-ultralineare-triodi-virtuali/

There are many others curve tracer plots, but I will only report the ones above.

I fear that I may have created a problem for myself 🙂


I'm building a speaker using a BMS 12S305 (12", linear Xmax 11mm).
Using the formulas used by some manufacturers the calculated Xmax is around 14mm.
The design critieria, that has resulted in this choice is a compact, luggable cabinet and a decent output down to 40Hz (decent as in 110++ dB)



Given my need for transporting the speaker around I really need to have some kind of grille in front of the speaker to protect against physical damage.
Usually I use the standard round grilles that fits just over the speaker, but on examination it looks as if the membrane will hit the grille when pushing the speaker near its maximum extension.


I am not fan of the speaker wide nets (they seem to flimpsy to provide any real protection).


So: are there other options for protecting the membrane from physical harm or does anyone know of a method to provide more space between the membrane and the grille?


Regards
Martin



PS: This may not be the correct forum, but I guess it is here most experience with high Xmax-speakers is found

Long time builder, inexperienced designer. Attempting to make a simple low noise mic pre, with a high impedance input suited for dynamics & ribbons. Came across this circuit by Bob Cordell, dual jfet LSK489 with presumably an impedance in the many many mega-ohms. Anyone built one of these or something similar?



https://www.cordellaudio.com/JFETs/LSK489appnote.pdf page 11/12


I’m mainly trying to figure out the line driver, be nice to use both halves of the 4562 or I could just whack a THAT1606 on the end. Or use a 1646 instead of the 4562 entirely but it might be too hungry coming straight off the transistors without an opamp buffer? Or of course simply do an impedance matched driver after the existing buffer like so



The other thing is this pre apparently provides 60dB, it’d be nice to bring that up to 70. I’m not sure if that’s better squeezed out of the transistors at the front end or done at the end with an opamp?

Any thoughts? Thanks in advance

Hi all,
I'm looking at using the transport from my CDB630 and rebuilding/modifying to improve performance. Seems to the the floppy clamp/holder could be improved along with other mods to reduce vibration. Read someplace about a magnetic clamp or some other design? Maybe move it into a better chassis (thick aluminum w/vibration damping)? I added damping to the top cover, 1lb brass weight on top and sorbo iso-feet under chassis, which all made an improvement. I still like the DAC (crown S2) out to a tube stage, but might want to try a different DAC just to compare?
Or maybe someone has a Cambridge, Sony, Teac, etc transport for sale?

Hey guys,

has nobody some experience with the device mentioned above? It comes in two versions.

I am starting a new project. I am updating the satellite speakers of my system.

Last year I completed an active 3-way system with SB 12” woofer, SB 6” ceramic mid driver, and SB 1” ceramic dome tweeter. The Hypex amps located in the satellite stand, providing 250 W for the woofer, 250 W for the mid, and 100 W for the tweeter. The bass driver is mounted in its own cabinet, located a few feet behind the satellite. Crossovers are 200 Hz and 2 kHz. I have been astonished at how excellent the SB ceramic drivers have been. https://www.diyaudio.com/forums/multi-way/352767-active-3-hypex-sb.html

I always intended this system to be a learning experience, and I had always planned to build a more refined system later using better drivers. Originally, I was leaning toward ScanSpeak revelators or illuminators. I plan to keep the woofer boxes, and with the modular design with the amps in the stands and separate woofer boxes I can painlessly update the satellite speakers.

In October I purchased a pair of Satori textreme tweeters and a pair of Satori textreme 6” mid drivers. I made a set of measurements using a 24” x 24” test baffle, and later a prototype box. I posted the results here Link. https://www.diyaudio.com/forums/multi-way/343831-sb-acoustics-textreme-61.html post 608

I have begun construction of the new satellite speakers. The new cabinets will be similar, but not quite identical to the old ones. Like the SB ceramic boxes, I do plan to build a double thick front baffle, 1.5 inch thick. The sides will be profiled with a 1.5 inch radius round-over bit, exactly like the SB ceramic boxes. This new build will use a 2 layer plywood baffle instead of a composite solid wood / plywood baffle. Before I did not have enough experience with veneer to confidently apply it over a curve, so I used solid wood. Now I know I can do it with veneer. The top edge will be chamfered at 45 degrees to a depth of 1.5 inch.

The SB ceramic box is 13" H x 10" W x 9" D. The new box will be 13.5" H x 10" W x 9.75" D. So slightly taller, slightly deeper. The arrangement of the internal braces will be different. I learned a lot while making the first cabinets ("learning" is code word for screw-ups). I attached my simulation of the baffle diffraction effect on the tweeter response.

I do not have any digital representations of the cabinet design (CAD or Sketchup). I did that kind of thing for 30 years and it feels too much like work... I like pencil and paper.

I value everyones input. As I optimize the filters, I will share my measurements, subjective opinions, and my thought process...

Hello,

I've been involved with music for decades, actively in the past, but since I realized my talent didn't match my expectations , I prefer listening music. I enjoy my classical record collection and have switched to tube devices with full-range speakers in recent years. I hope my hearing lasts for a long time.

Best regards from Austria

Franz

$180 shipped in USA.

When I opened the package it FELT like the cardboard had never been opened before and the cardboard looks new.
As if the cardboard had never been bent past a certain point.
On both sides of the box the cardboard felt like it was never opened before. Do you know what I mean?
BUT THIS DOES NOT MEAN THEY ARE NEW.
I have no way of testing them.
If you want to test them I am in Nashua, NH, USA.

(3) NOS RCA 12BH7 12BH7A BLACK PLATE D Getter VACUUM TUBES 58455 -- NH USA --

No HiFi here! Just Audio.

I bought 4 mini PC; all of them have the audio jack missing the connection to the mass when off. So if your speakers remain on, you hear an annoying hum.
When you turn on the PC, everything is fine, no more hum, if you check with an Ohm meter, the mass is now connected.

I solved this issue by connecting the audio mass to the mass of the mainboard with a short bridge. Very simple to do, but you must be very careful.

The operation doesn't need any explanation, just look at the pictures.

BTW, you better replace the SSD pad with one 1mm or 1.5mm thick, the stock one doesn't touch the bottom panel, so it is useless. I also removed the SSD label. The right pad stays with the bottom panel, not with the SSD, when you open the PC.

Cheers!

A pair (2 pcs) of Faital Pro HF10AK compression drivers for sale, including a matching pair (2 pcs) of Faital Pro STH100 horns, all are brand new in factory boxes. Drivers are 8 ohm version.

These need no introduction and are usually sold for alot more. I paid almost double my selling price. My loss is your gain and I want these to go to a good home.

Price is $390 shipped to the lower 48 US states.

Hi all,

I was wondering if there is an old thread to point me to about how to customise the Onken / Fonken / etc. cabinets for different drivers, or if not, if somebody familiar with these can run me through the tuning process in general terms to make sure I'm not missing any considerations. I've read through and searched within a few Onken-related threads but not found anything comprehensive, but that doesn't mean it isn't out there. I've also definitely seen a few threads asking for advice about specific drivers lead to comments about appropriate box sizing but suggest that tuning will need to be done for them but can't find anywhere saying what this would entail.

Additionally, I've seen other threads saying that some designs for these behave like traditional ported enclosures and others function like aperiodic ones, and I'm not sure which the spreadsheet is for (presumably not aperiodic) nor if the design considerations are different for the other type.

I've been looking at the 2011 thread by Togril on creating an Onken for the Tang Band W5-1611SA, who seemed pretty happy with how their build went. I have the SAF model of the same driver sitting unused at the moment, so I thought I'd see if I came to the same sort of parameters before I start building anything (and I've got some fairly hard space constraints where I'll be putting these speakers that would mean that if I can find a way to design it to be marginally shallower that would help too).

I'm aware that there is a spreadsheet by one of the gurus of these speakers out there - the one by Cyr-Marc Debien from 2000 - and have been playing around with it. As far as I can see, the goal is to figure out an enclosure of about the right volume that is a sensible shape (with the usual considerations around ratios of length/width/height as for any other box) for the driver parameters whilst keeping enough box depth to allow for the required vent length that the calculator spits out. Some drivers will basically be unsuitable, and others can easily be fit into these constraints.

Where I'm getting confused is around decisions to do with vent dimensions - obviously making these wider or longer or changing the total number of them will dramatically change the required vent length, but I'm assuming they also impact sound in other ways so have no idea what I should be picking here as a starting point or what changes are generally likely to be 'safe' vs causing other issues.

Assuming this spreadsheet is a good way for me to design a box, I was also hoping to clarify some parameters / outputs in the spreadsheet itself that have me confused:

Firstly, why there are separate fields for "effective vent length" and "corrected effective vent length" and what is being corrected for? I'm assuming the corrected one is what I should be aiming to use in the final design, but wanted to make sure I'm using the right one, as in the tests I've done it is usually 10-20% different to the 'effective' one.

Secondly, what is the impact of changes to the "n=" / "Onken alignment" parameter on the final result? I'm assuming the 6.34 was what the original bass cabinets 60+ years ago (presumably designed by trial and error) ended up having once more modern simulation/calculation methods were applied to the old designs, and the 5.7 is a better compromise that has since been identified mathematically, but I'm not sure what it is compromising on or what changes up or down from this 'ideal' value are likely to do.

Finally, what influences the tuning frequency for the box/vents that this spits out, aside from driver parameters? Fb is one of the calculated values and can't be set by the user. With other vented enclosure calculators (or at least subwoofer ones) this is something that I believe the designer usually decides on along with box size, target Q etc, and these then are used along with the (fixed) driver parameters to determine the vent parameters, both area and length. Here it seems we are coming at this from the other side - based on a given vent area and driver parameters, a fixed 'optimal' volume, Fb, and Q are set, and the required vent length to achieve this is output. Is this understanding correct?

Hopefully someone can set me straight or otherwise point me towards resources that will help me figure this out on my own!

I have for sale, brand new in original factory boxes, never used, mounted whatsoever. They're NOT B-stock or gray market. Purchased locally brand new from factory authorized dealers.

DBX Driverack Venu 360 loudspeaker processor (96k sample rate, with AES/spdif inputs), brand new in original box with manual, sells regularly online for about $1000. Asking $600

QSC GX7 2 ch professional power amplifier, 800W/ch @ 8 ohm, 1200/ch @ 4 ohm. Very clean sounding, reliable, light weight. Brand new, sealed in factory box. Sells regularly online for about $900. Asking $500

Both units priced for quick sale at almost half of the regular selling price. Also advertised locally for sale in my area.

Shipping only to lower 48 states - pls ask me for a quote.

Send me a PM for more info if you're interested.

Hi,

I'm a high-end audio enthusiast, interested by modding, tweaking, and restoring things. I love vintage speakers and amplifiers, have a tiny collection of cool old gears (cabasse sampan 311, celestion ditton 33, jmlab 913, luxman amps, Sansui amps) and some modern stuff (hypex, topping dac, adam audio active speakers).

I've done some mic tweaking too, DIY builds. I'm a musician and a videographer, so I use a lot of my builds for work.

I'm based in the south west of france, near Pau, and i'm a long-time reader of diyAudio forum.