This is what i made up in ltspice, it works like crap becuse i probably missed something

Now I'm wondering, due to air dry alkyd varnishes like Elantas Elmotherm 009-0008 getting more and more expensive, are they somehow superior to regular alkyd boat varnishes you'd find at regular paint shops? And to what extent? Drying time? Anti-corona additives? Could regular alkyd varnishes contain offensive to the transformer chemicals?

I wanted to build the Kondo M7 all tube pre-amp, but discovered that the company founded by Kondo has taken the design a little further and my project will now take advantage of this to see what’s changed, what hasn’t changed and deliver the ultimate M7 for my system. The latest products being sold by Kondo Japan are very expensive so DIY is particularly attractive.

Although mine is a mono system what comes out of this still applies to the stereo version. I’m going to build from scratch, no ready made kits or pcb’s for which other threads exist to help those interested in that approach.

I hope this thread will be of interest, it’s going to look a bit like a diary of my build as it goes along. I really want it finished over the coming weeks.

Contents (by Post #):
25, 38 & 41 - main H.T. Power supply, schematic shaping up on #46
30 - adding a heater winding to an off-the-shelf power transformer
54 & 61 - shunt regulated heater supply
77 - H.T. power supply board build
88 - fixed -20dB attenuator design
90 - Line amp schematic
97 - Phono amp schematic
106 - Line amp square wave test results
111 - Line amp frequency response test results
112 - RIAA curve compliance test results
35 & 115 - RIAA design analysis, ‘correcting‘ the OEM design
118 - the finished unit

Dea DYIaudio community
I’m Marco, another fellow from Italy

My father passed me a strong passion for good old hi-fi tech and music on vinyls 🙂
I had the chance now to upgrade a bit my audio system and need some how to make it sound at best

Thanks in advance

I've got a CS-800X that's used for a "stereo" in a shop for many years. Doesn't see a lot of high output use, just running ambient music. Yesterday it started buzzing loudly so it was switched off. I turned it in today to debug and it initially buzzed loudly alternating left and right channels so I turned it back off. When I powered it back up again now it's just flickering green on the power light, again alternating between channels. The relays are clicking intermittently. DDT lights are off, speakers are fine (running on another amp now), fuses are fine and have never been replaced (by us), no other indication of issues.

I took the lid off and immediately noticed R103 on the power board (20W 400ohm) is coooookkkked, it's heated the adjacent areas around the board but looking at the schematic it looks like it's related to the fan but not much else?

~75V on both capacitors

Going to start towards verifying +26V and +/-15V output. Any other suggestions on where to start/what to suspect? Seems like it should be on the power board given that it's effecting both channels but that could turn out to be a bad assumption 🙂

Perry Marshall's Live Edge Dipoles inspired me to study them with the aim of developing my own variation on the theme. To do so, I had to develop Vituix models for the dipoles and for the Uframe, which I'd like to share. Perhaps someone can compare model predictions against their speakers.
Dipole modeling in Vituix is well known but running the model made clear that with dipole coax drivers, the coax mid woofer cone was being used over a much wider range than done in multi-way open baffle speakers and that there were consequences to that.
A U-frame model starts the same as a dipole model. Per Linkwitz, the acoustic impedance mismatch at the back of the U-frame attenuates the rear wave. Per Krekovsky, the U-frame's 1/4 wave resonance needs to be tamed which makes the Uframe response cardioid like in the low end.

I will do separate posts for each of my models

Hello friends. Im glad to join you here.
Love to bild speakers and amps. That is my favourite hobby for many years.

This totally reminds me of walking into a class for the first time and the teacher has you stand up and say something about yourself, which then leads me to the movie Stripes….. I can’t remember the guys name that “I like fast cars and fast women”.
I have no idea what to put here, I’m only posting here because I have to to post elsewhere on this site.

Disclaim: DIY at your own risk. No responsibility will be taken if precious amplifiers/speakers are blown.

Introduction
More and more SMPS are used in audio amplifiers. Meanwell desk SMPS for the newest V-FET amplifier is used. The feedback to use SMPS in the amp from all lucky winners is generally positive.

SMPS
Phoenix Contact Quint-PS/1AC/24DC/5 is selected for the test because of seeing and using them a lot. Its output voltage is 18-29.5VDC adjustable, very handy for future testing and different amps. The output current is 5A, but it has a boost mode, which allows 7.5A at 24VDC if the ambient temperature is not over 40°C. The residual noise is 40mV P-P, which is very low. They can work in parallel to increase the current or series to double the voltage. It is very well built, metal case, 105°C Rubycon and Nichicon capacitors. And all other components look very solid.

The most important feature is the build in protection function. They have built-in protections.

Capacitance Load Test

“True audiophile nervosa” cannot tolerate the oblivion of their best sounding, huge, beautiful capacitors from their beloved amplifier power supply. Some capacitors are be added in.
In the spec, the SMPS used does not list a max direct load capacitance load. But other similar SMPS can have 3000uF-8000uF direct capacitance load. Started from 1000uF and ended with a 10000uF capacitor, the SMPS can start. But one of the PS started oscillation on pure capacitor load. A 4.7K resistor is added and give the PS some small current load to solve the problem.

Does anyone know the parts number for a replacement woofer for the Tannoy D700? A friend has a pair with a missing woofer - I assume it got sent for re-coning at some point and never came back...... I could take the remaining one out and measure to see if I could find an alternative pair, but it's definitely option two. Any info - or replacement suggestions - would be most welcome.

Be keen to get them working again - a quick internet scroll seems to rate them very well.

I don't know what to do.
The amp only turns on after a few tries after being pluged in, but once it turns on it will work fine and then i can turn it off and on and it will work as intended untill i unplug it for a random amount of time, and then it goes back to not turning on.
If i remove the cover to try to find the problem, the amp turns on no problem even if left overnight, so the problem goes away
Any ideas on what could be wrong?
Attached is the power supply section of the amp

If i understand the circuit correctly
the switch turns on mains via a inducter to the main rectifier and capacitors via two inrush limiting resistors. Before the rectifier power is bypassed to transformer T101 that feeds a 7815 voltage stabilizer that powers a IR2153 half bridge driver that drives T104 so that it will provide all voltages needed by the amp and turn on the power relay to bypass the two inrush protection resistors.

I have used Alpha pots (made in Taiwan) in the past. I ordered a batch of pots for a project and have found that although they still have a nice smooth operation, their resistance tolerances leave a lot to be desired. In dual pots, the sections may or may not match. A 500K dual pot may be 500K in one section and 450K in the other. In a volume control, at lower volume levels, this causes the channel balance to shift. To get a pot with both sections the same resistance, you have to order a bunch and weed out the bad ones. The audio taper pots all seem to not really be an audio taper. They are more like linear until near the end of rotation, then suddenly the resistance changes. Mechanically they are nice pots, electronically not so much. Any suggestions for more accurate pots?

Poor Man’s Planets

Some time ago, in a grey November day I decided to do something about the sound of music in our bedroom. We used a Bluetooth speaker located in the top shelf of our bedroom commode/sideboard, which was neat but no real stereo.

Since I’m a bit of an audiophile naturally I would prefer a (cheaper) alternative to Duevel’s Planets, which are superb sounding omnis with a decent amp, but meanwhile around 1k €/$ a pair and quite large for such a small room - hence the name for the project.

Disclaimer: For me the greatest motivation to build something, whether it is artwork, music, software, home improvement, bikes or this speakers is to create and get something new, which wasn't there before and cannot be acquired otherwise – the days I was poor in any meaning are long gone.

Searching the internet and some retailers I found out about a building kit for classic omnis – as satellites with optional sub woover which would be a basis for some modifications but still 600 to 700 a pair – with unknown sound quality, and no builder or user feedback available … the idea was to use the shelf board as kind of box volume / semi open back solution for the “satellites”…

During searching for wood materials to make the base board from, the Focal Performance Expert Flax PC165F dual speakers came along since I was searching parallel for posibillities to simplify the design, and they are two way speakers and have a near perfect wood-color fabric membrane, and so the idea of simpler “Planets” with only one diffusor/reflector was born.

As they arrived I got my first headwash during this project: “No, you will not build such ugly color-mismatching wood extensions to the shelfboard!” and… much more later “Perhaps in white*, and I don’t want to see any black from the bed!” harsh conditions – I was speechless for some time – because I introduced the project some time ago – and it was wood the whole time.
*which is the second base color of the sideboard

So… time to redesign the materials and composition, from a straight plywood multiplex composition to a plywood – white plastics composition with white ironed edge-Tape around.

I changed the planet holder bows to chromed copper pipe, and bought white Christmas balls in 10cm diameter and a collection of 2 to 3cm diameter ones because it wasn’t possible to figure out the size of the sockets without buying and dismounting them.

And the main board to precoated white shelf boards from the hardware store.

After Christmas (I ordered my own present – a 200W Douk Audio ST-01 PRO Mini HiFi-tube amp)



…all materials had arrived I started to build.

As built plan (after) first build:



In a first step we cut the 125mm Sewage elbows parallel to the shelfboard in my father’s workshop.



I had to remove the inner section later.



I made several cut outs from the plywood until it fits.



Two layers of plywood were glued together/laminated and screwed+glued to the parallel boards, which have been screwed to the sewage-elbows before,





and the upper bows filled with brick-layered cut wood strips – I was not able to saw out the exact needed shape with the electric jigsaw, and was not enthusiastic enough to do so with the manual saw.


I had changed the width of the horizontal ear boards because the planned width seemed too narrow during building. In the effect I had some trouble with cutting and glueing the plastic board because I had to mirror one side to minimize waste and gaining enough area.






Turns out copper plumbing-Ts are eighter too large or too small, such I ended with screwing a short section/ring of 30mm plastic pipe to a wooden peg which perfectly fits in the chromed copper pipe bow. In the larger glass balls I put a wooden strip with a hollow nut in the middle, and in the smaller glass balls I glued a fitting mechanical bolt/screw and screwed it through the plastics ring together.



First test of the setup was sobering, I was disappointed, the sound was telephonic with a lot of resonances and nearly no bass. I had to ad to add additional wood bars behind, and wood strips to the front board to eliminate resonance of the boards and sound damping layering in the pipe-elbow ends, the elbow itself and a squared absorber foam block in elongation to the front board



– And to finally get some bass I added a passive bass reflection absorber box in the middle of the shelf.



And I added another wood block as support beam for a furniture foot used as a clamp to press the upper side of the speakers’ boards against the top board of the side board.

Now I was satisfied with the sound for some time – real good jazz speakers for soft to medium volume, with very precise stereo position and depth… And with some SciFi finish…



In May or June I built additional front boards from new 60cm long shelfboards (and remainders from the building process as support in the back) to increase the volume of the boxes mainly for bass…

It got more bass, but lowered brilliance and a second “headwash”, she didn’t want to see the new fronts again – too large!

So I only tested them from time to time but was never satisfied myself…

Some weeks ago I had another “sting” and sat down to redesign the speakers in terms of used volume and resonance prevention – I ended up with larger, slightly downward pointing front board - preventing steady front to back and “circular” reflections. Second topic was a slightly backward aimed /”opening” back board to prevent in phase front to back reflections – but both would require a real wood workshop for milling straight flush egdes – better tools and a complete disassembly and nearly total rebuild of the speakers… both a bit out of reach…



But since I got the “sting” I decided to do it half way! I used the electric saw to remove half of the back boards and the wood strips to the front. Then I added the 60cm front board which I cleaned from the supports and did it in a slide angle as planned and shifted so only 12cm longer, as long as the added absorber foam block before, connected / supported with wood glue, wood strips and 6 wood screws. Layered with flooring fabric at the ends – the absorber turned 120 degrees inwards. So there is a nice slight bass reflex horn like design (including the passive box) now.



The appearance changed a bit from technical (visual pipe elbows) to clean Bauhaus style.





The sound is brilliant, precise stereo position (i.e. Yosi Horikawa – Bubbles), room filling – great depth esp. in ambient (like) productions (i.e. Pink Floyd – nearly any Intro, esp. High Hopes [from the division bell], Hattler – Sand am Meer [from Warhol Holidays]; Carbon Based Lifeforms – M [from Interloper], Massive Attack – anything from Mezzanine, Dan Gibsons Solitudes – Rocky Mountains Suite), decent bass – I am very happy and satisfied …

…awaiting the final “headwash” when she notices the larger front boards, if, ever…

probability sinks, weeks in the aftermath … 😉

in the moment i'm writing this i'm lounging on the bed, listening to Moby and Two Lanes and simply enjoying the great sound...

Hello, I have spent part of this summer to try to build a nice two way speaker. I have used VituixCAD2 to help with the layout of crossover. The speaker elements are Scanspeak D2010, 851300 Tweeter (oldish but not used) and Monacor SPH-165KEP. Unfortunately there is no measurefiles from ScanSpeak or Monacor, so I have used Vituix to plot. It seems to work. I posted one time earlier here at diyAudio as introduction and was recomended this forum/thread. On recommendation from @knotscott I tried to make a RC zobel to improve impedance. Crossover at 4000hz is my goal and also what ScanSpeak tells. If I raise resistans on Monacor everything falls apart in some way, but impedance can be set to 6-8 ohms. Any suggestion is welcome.

Hey guys.

I have the chassis of an old Alesis poweramp, which I would like to turn into a relatively low power (20-40 watts I guess) stereo speaker amp for my living room TV.

I'd like to use the chassis as-is, and each channel has space for 7 transistors on its heat-sink. Is there any class AB design that you guys could recommend? I'm willing to design my own boards if needed, no need for a complete DIY kit.

Thanks 🙂

It´s 135 mm
Mark´t 8-9 ohm at the backside, but no modelnumber.

Regards John

A couple years back I went from a pair of passive dayton based bookshelves to a fully active system based on the daton PCX-12 coaxial. Details can be seen here: https://www.diyaudio.com/community/...s-the-box-less-important.392703/#post-7222109

These were a real learning experience from being my first go at active XO's, measurement, and PA gear. From the active XO side of things, I'm not looking back. The results that I have achieved (after investing the time) have exceed expectations that i dont think my patience could match rolling components in a passive xo.

Being PA coaxials with a small wave guide, the speakers have a very very narrow sweet spot for a residential sized room. I thought about experimenting with different waveguides but dont think I could sufficiently close the gap. One thing these do deliver though, is the party, and this was a design target for these. The super small sweet spot is 90% of my motivation to build a new set of speakers but solving this has many avenues that I could take. Some of my ideas are below, id be interested in hearing others suggestions.

1. Re-use the drivers but put the CD in a proper horn. Bonus, it only costs mdf and time. But again, the directivity may leave me lacking.
2. Go back to a traditional dome tweeter and build a set of 8" MTM's. This will help my LF xover to the sub and hopfully give me more even bass in the room/floor.
3. Make a 3-way 6.5" MTM with a 10 or 12" sub in each and leave the low lows to the UM-18.
4. .....Something else that wont break the bank

FS Four vintage US made Tung-Sol 12AX7 tubes. Tested and strong on TV-7D/U tester at 40-42 where 32 is passing. Price is $49 plus shipping within the US. Payment by check or MO, no Payal or other online payments so please don't ask.

Hi Folks,

here is an embarrassingly simple-sounding question: can I connect two power outputs of a 9V power supply to get enough current for a more power-hungry digital pedal?

I am considering getting a pedal board with an integrated power supply, probably this one: https://www.amazon.com/dp/B0CT34HZRG

The problem is that these board's power supply come with a bunch of 200mA outputs, and I need 300mA for my main pedal - Flamma FS06 amp modeler. So I was thinking of getting a splitter cable like this one (https://www.amazon.com/Mozeat-Lens-Splitter-Electric-Adapter/dp/B0CZ8JNS12) and just use two 200mA sockets for the Flamma.

Is there any reason it won't work? Thanks!

Hello,
How much does a preamplifier impact sound quality? Should the electret capsule primarily determine the sound quality? I’m considering purchasing the AD620BRZ, INA849DGKT, AD797ANZ, and MUSES03 for testing, but I’m unsure if they will work well together. I’m working on building a microphone for musical instruments and would appreciate any insights.

Thanks!

Hello,

I have built a subwoofer box for the budget subwoofer "GRS 15PF-8" and it didn't turn out the way i wanted/expected it to, let me explain. I have installed winisd to do some calculations on what box/port size ect. I have watched some tutorials from "Diy Audio Guy" on what parameters I should look at and what they should be. And I came to the conclusion that a box of 50x50x50 cm =125L or a little over 4 cuft minus the subwoofer air replacement is about 4 cuft and a port of 4x50 cm of 50 cm long gets the tuning frequency's matched up pretty well. This configuration gives a Transfer function magnitude graph that looks like this
with almost an 16 db gain at 29 hertz. Now here's the problem: I built this subwoofer box and it does not sound like this AT ALL!! It more sounds/feels like the 16 db gain is at 60 hertz instead of 29 hertz. I have taken it outside to ensure it is not something with my room and it shows the same results outside. I don't know what i did wrong here and i would really appreciate any answers to what it possibly could be.

Nanno Haasjes

ps. the amplifier i'm using is the skytek spl 500 (a little overpowering it i know)

Ha! (mods don't lounge this yet)

After dozens of diy experiments under a wide range of (domestic) conditions and speaker/listener placements (including height), I'm reasonably convinced by the empirical evidence and common-sense inference to state a theory of soundstage imaging depth. Bits had been posted over time to the Full Range Photo Gallery and various threads such as on-going "ragged coaxials".

Metaphysics or psycho-acoustics -- a progression?

Claim 1: It is the monophonic recording-through-to-playback-chain that is responsible for enabling soundstage depth perception; the stereophonic L/R is responsible for enabling horizontal directional perception.

Claim 2: A necessary and sufficient condition for a monophonic audio chain to enable the perception of soundstage depth that projected well beyond the speaker, is close time- and phase-alignment (coherence), including very-high-frequency components of the sound.

I call this effect "audio-lensing" and experienced it quite dramatically, replaying phone-recordings of my coherent near-field 15in/ceramic-tweeter "reflector-coaxial" (playing virtuosic violin music). Aiming the phone-top-end (Vivo iqoo Z7 with stereo speakers at the ends) in various directions and at various distance-combinations from self, and room boundary 1-7 meters away, the sound source was heard to project/float mid-air far from the phone and near or just-past the wall in the pointed direction. In one extreme case the sound "played" from second-floor balcony at ~7.5m. The phenomenon as observed was analogous to "lensing" in that the distances from the phone to me and to the perceived source were in reciprocal relationship; source was farther away if phone was closer to me (and the reverse). Again, this was a stereo-phone playback with one end-speaker pointed away, of recordings of a monophonic coherent near-field 15"/ceramic-tweeter 2-way. This phenomenon was not observed replaying other people's sound-clips but I did not have time to test very many.

I will be adding experimental observations I've had, and inferences to back up this theory. And audio-clips if possible. I'd appreciate members sharing their experience and insight.

https://www.diyaudio.com/community/...ials-with-ragged-response.408887/post-7783316

Pico's Dumb (ie Pico is Dumb) Biasing Trick for F6 and other Amps

As you may or may not appreciate many devices have a positive, negative, or virtually zero temperature coefficient.
Most mosfets have a positive temperature coefficient, ie as they heat up they draw more current when biased with a constant voltage source applied to the gate of the mosfet (provided the bloody voltage is adequate to turn it on).

To reduce the effect of this increasing current draw as the device gets hotter we can do a few things.

1) Reduce Delta T of the devices, eg larger heatsinks, better thermal pads ie improving Case to Heatsink performance, etc

2) Using source degeneration which acts as a form of negative feedback, ie as the device attempts to draw more current, an increasing voltage drop occurs across the source resistor which effectively reduces Vgs which then stops or reduces the amount of thermal current drift.

3) Using NTC thermistors in the bias circuitry, which effectively reduces the Voltage at the gate as the thermistors heat up, eg as seen in F5, and elsewhere. I used a similar method to this, in F4 beast builders ie building push-pull amps (mostly with hockey pucks) with zero degeneration.

4) Active bias control circuitry, optocouplers, hall sensors, discrete designs.

You can obviously also combine some or even all of these methods, to get the result you need.
There are probably quite a few more techniques than this, but I am telling the story and I don't want it to be batshit boring.

Even though I have successfully used method 3, and 4 in the past, I don't like "intelligent solutions", I like dumb simple solutions that don't require maths or too much intelligence.

I have often thought, there has to be a dumber way to do this.

So I am sitting on the toilet (it always happens like this), and I am considering my options with regards to voltage references, TL431, LM329, Zeners, Leds.
I start thinking about Zeners and leds, since they are dumber than the other devices, and remembering that Zeners below 5V have a negative temperature coefficient and zeners above 5V have a positive temperature coefficient, the light bulb turns on "aahhh you bloody dumb bastard" and gave myself an uppercut for not considering this earlier.

Many here have either personally built the F6, or are at least aware that in many cases, the 5.1V zener shown in the original circuit diagram is not quite adequate to produce the required voltage at the gate to bias the F6 to the required value.
Most of us have used 5.6V, 6.2V, 6.8V zeners etc, some have used LM329.

Well, all these devices have a positive temperature coefficient, you could probably say that LM329 is effectively zero but it has a very small positive temp coefficient.

So, what is stopping us from using 2 smaller valued Zeners to achieve the required zener voltage eg 2 x 2.7V zeners, and achieve a slight negative temperature coefficient.
LEDs also have a negative temperature coefficient with regards to Vf, but we will first consider comparing Zener diodes.

Anyway, so I decided to compare the observed measured differences in biasing up a Vishay IRFP150 mosfet (with zero degeneration) using 3 different zener configurations:

1) 2 x 2.7V zeners in series (effectively 5.4V)
2) 5.6V zener
3) 6.2V Zener
4) 3 x Green LED LTL 4231N - tested at a later date

The zener diodes were fed around 5mA in each case (more detailed information below)

A multiturn trimpot was used in each case (just like F6 circuit) to achieve exactly 3.925V at the gate.
I used zero degeneration on the mosfet to better illustrate the effect.

Results
------------------------------------------------------------------------

Case (1) 2 x 2.7V Zener Configuration
Initial Vgs: 3.925 V
Ambient Temperature: 21.8 deg C

Id at turn on: 1.32 A
Id at thermal equilibrium: 1.68 A

Vgs at thermal equilibrium: 3.899 V

Delta Id after thermal equilibrium: 1.68-1.32 = 0.36 A
Delta Vgs due to Zener: 3.899-3.925= -0.026V (negative 26mV)
------------------------------------------------------------------------

Case (2) 5.6V Zener

Initial Vgs: 3.925 V
Ambient Temperature: 21.8 deg C

Id at turn on: 1.32 A
Id at thermal equilibrium: 1.95 A

Vgs at thermal equilibrium: 3.936 V

Delta Id after thermal equilibrium: 1.95-1.32 = 0.63 A
Delta Vgs due to Zener: 3.936-3.925= 0.011 V (positive 11mV)
------------------------------------------------------------------------

Case (3) 6.2V Zener

Initial Vgs: 3.925 V
Ambient Temperature: 21.8 deg C

Id at turn on: 1.32 A
Id at thermal equilibrium: 2.25 A

Vgs at thermal equilibrium: 3.954 V

Delta Id after thermal equilibrium: 2.25-1.32 = 0.93 A
Delta Vgs due to Zener: 3.954-3.925= 0.029 V (positive 29mV)
------------------------------------------------------------------------

Brief Discussion of Results

As predicted during my toilet brainstorming, the 2 x 2.7V zener in series produces an excellent result, with a delta Id between turn on and thermal equilibrium of 0.36 Amps. This was achieved using the negative temperature coefficient of a 2.7V zener to our advantage.

The 5.6V zener is twice as bad, and the 6.2V, almost 3 times as bad as our 2.7V zener setup.

The test was performed on a large heatsink (relative to the heat dissipation of the device) flat on the floor, with excellent ventilation.
If the same test was repeated on a relatively smaller heatsink with regards to dissipation like one you might be using, and performed inside the chassis of an amp, we would expect to see an even greater positive affect with regards to using 2 x 2.7V zeners.

However, if I were to repeat this test exactly as performed above using degenerating resistors the results would be closer together.
This was merely done the way it was to clearly illustrate the effect, and I always try to avoid any kind of degeneration, so this kind of thing is of interest to me.

You could also try 3 x 1.8V Zeners for an ever greater effect.
Or you could use 2 x 3V or whatever you might have. Basically anything below a 4V Zener configured for the voltage you need, is going to have a nice affect.
EDIT: A 3 x LTL 4231N LED combination was also tested and gave favourable results like 2 x 2.7V zeners, however it has better regulation than the Zener combination.

It's up to you if you want to try this out. I am not into preaching, just sharing.



Test Conditions:

Zeners tested:
5.4V (2.7V x 2 in series) BZX55C2V7-TR
5.6V BZX79-B5V6.113
6.2V BZX79-B6V2.113
LED: LTL 4231N

Mosfet:
Vishay IRFP150

Trimpot:
10k 0.5W Bourns 3299Y series

Resistor feeding current to Zener
3.3k CMF55 (zeners biased at approximately 5mA - close enough)

Powersupply Feeding Circuit
Linear regulated lab powersupply set to 23V

Heatsink
MF35-151.5 just laying flat on ground.

Ambient Temperature 21.8 deg C

Biasing Circuit
F6 basic biasing circuit.

I'm looking at a local older speaker 2000ish that has a blown tweeter. Before I buy, it would be great to figure out the cost of buying a replacement tweeter as I'd probably have to replace 4 tweeters (each speaker has 2 tweeters). Seems like the original tweeter is a Scanspeak 2800. Problem is I can't seem to find data on it.
Any thoughts?

Hi, Can someone change my email adress on my diyaudio account ?. Some f**kery from google made my old email unusable , can't access it .
My current mail I can not acess anymore is bruno.ausmann.1@gmail.com . I would like to change it if possible, not a big deal , I just can't receive notifications anymore .
Thanks.
- Bruno.

I got the .asc file of the class a power amplifier schematic. in the description the PSSR value is 89db at a frequency of 1kHz. how do I get the PSSR value of 89db? can the master here help me to update the .asc file and display the PSSR value?
thank you in advance

I volunteer at my local Repair Café, a place where people can bring broken things to be fixed. I specialise in electronics and currently have a guitar amp to look at. The expertise on this forum would certainly help me when I get stuck!

Pretty straight forward guitar distortion, sort of compressor at some pot values. I think at this value its pretty much like grill distortion (putting a little DC at the grill of a single stage valve with a high value pot).
Second 1M resistor is amp input Z. Its the regular jfet as variable resistor circuit...

Should i add a buffer or is it not needed? Is there an easy way to get "automatically" more gain when there is 1.5V at the gate so the "pedal" is more gain stable?

Hi.
I am constantly looking to improve my hifi setup and prefer doing so at lowest cost possible. I have more time on my hands now since my capacity for working is reduced after a period of illness. I have a good hobby level knowledge of electronics and hope to be able to contribute with my own knowledge, as well as enjoy the wisdom of others.

Time to revisit Aleph J. I've been pondering this for a while, one of my new aims is to keep single ended throughout the chain (aim: unadulterated phase, so no push-pull M2, F4 or F6 designs). Options available to hod rod the Aleph J to provide more power into 4 ohms as I see it are:

1. Lower supply voltage, say 20v, increase bias to standard Aleph J. More into 4ohms, but power into 8 ohms is down to 20w.
2. Use Hughs/XRKs Alpha Nirvana instead - front-end is based on the Aleph J, but the output stage is Single-Ended Push-Pull. Good for 34W into 2.1ohms loads according to this post. Disadvantage/advantage, will sound different to the original Aleph J (Nirvana has a higher damping factor), little bit of phase shift of only 5.3deg at 20kHz.
3. Build standard Aleph J, but use one less output device per side (?) and/or reduce bias and use the Aleph J as a driver for a BA1 single ended output stage. Trim voltage of BA1 to 20-22v and bias as high as chassis/mosfets will take. Limits ultimate volume level into 8ohm loads, but should breeze through lower impedance loads.
4. Use double die output transistors with standard Aleph J (like IRFP150?) - is this an option, anyone done it?

Cheers

If the 2 boxes are the same dimensions and port size, but one is a folded voigt, would the low end bass sound similar in punch and detail?

Good day, I’m purchasing some parts but I’m seeing a product status that I’m not understanding…. I need mosfet IRF1404 from DigiKey but suffix as follows ZPBF is 180amp and the PBF is 202amp. I want to choose the one with the stronger amperage but what does “Not for New Designs” means on the status?

I've gone down a rabbit hole lately after learning about the Ikonoklast Tweeters. I have a rebuilt pair of the Infinity Walsh tweeters that I want to use in a 2 way Omnipole design. I found various posts about the old Walsh tweeters on this site and others describing their sound and how to rebuild them so I bought a pair needing TLC on EBAY and did just that. These Walsh tweeters are perfect, after all, with their 360 degree dispersion, for an Omni-pole. They are very fragile though and I am not sure exactly how to add them into a 2 way? So then, doing a bit of research, I saw the Ikonoklast version, that I believe are based on the Morotola powerline series 1141a. They are very sturdy, and go nicely down to 1800hz easy to XO, add an LPAD etc... I am thinking about building a pair into infinity style Walsh, then seeing how they go. Should sound very very good. The Ikonoklast speakers have very good reviews, especially their tweeters. There are plenty of threads 'out there' on how to properly use piezo tweeters that don't discuss the Walsh style at all, but can give good guidance on how to get great sound and overall performance out of them.

I will be using the SS 15w8351k00 firing directly up into an acoustic lense. That driver will receive a 2nd order XO to roll off around 2k. The Piezo Walsh will get a 1st order cap in series which will give it a similar XO point. According to Ikonoklast this is fine for this piezo. I don't think it would have been as easy to get the Infinity walsh to cross that low. And I really don't want to cross the 15w higher.

I will use .0002 mil hard Alumium foil backed by packaging tape(Mylar). I found the Walsh cone template out on one of the diy sites. I will then glue it to shape and then glue it to the piezo element. I don't know exactly how the Ikonoklast tweets are built, so I have to go with how the infinity Walsh rebuilders do it.

I will probably test my speakers, when they are finished, with my rebuilt Infinity walsh tweeters just to make sure they work, then I will sell them on Ebay if I can get the piezo walsh version to work.

Anyway, anyone wanting to try an exotic tweet in a two way can maybe experiment with something like this. Or anyone wanting to build some cheaply for an old set of Infinitys. The Infinity Walsh tweeters are hard to find in working order.

Orders now are open on Abbado II NOS DAC kits - PM me and be sure to include your payment method and location so I can quote you inclusive of fees and shipping. Abbado II is based on the work done developing 'Stack DAC' but has a much more convenient physical footprint of 100mm * 70mm using a 4 layer PCB and a single power rail of 9V. The maximum height is 20mm. Design wise, it's non-oversampling (i.e. there is no digital filter on-board) and the input format is I2S (three signal wire) at 44k1/16bits active within a 32bit frame. BCK is 64fs so 2.82MHz, no MCK is required. Output is nominally 1.3VRMS with a 6dB gain reduction option on-board and a limited range of overall level adjustment from a multi-turn trimmer. The gain reduction comes in handy when you want to use a pair of Abbados to create balanced outputs, the balanced output level can be kept the same as when unbalanced. In this configuration, the trimmer allows interchannel matching of output levels. Our I2S splitter board provides the functionality to run a pair of Abbados in balanced mode.

Preferred payment method is via Wise which typically adds a 2% fee. Our receiving currency is CNY, alternatively USD or Euro. PayPal may also be used, in USD but will attract higher fees, 5.5%.

Price for an Abbado II kit : 428RMB (~$59,€56,£47)
Price for Abbado II built and tested : 620RMB

Shipping is in addition and depends on your location and speed of service. Courier (FedEx, TNT, DHL) typically takes 8 - 10 days and e-packet four to eight weeks. Not all locations can be serviced by e-packet though.

FAQs

What else is needed to turn the built up kit into a fully operational DAC?

First, you'll need a well regulated low noise power supply of 9V rated at 200mA or higher. An LM317-based board set to the correct voltage will suffice if you already have an unregulated supply (like a typical wall-wart). I don't recommend switching supplies due to issues with common-mode noise, its very hard to filter out. That disrecommendation doesn't apply though when both the DAC and amp are within the same box, in that case the CM noise isn't a worry. We can supply an LM317-based board with either DC (for unregulated DC) or AC (for a transformer) input option.

Second - you may need a digital interface card. I say 'may' because some digital sources produce I2S directly (like Raspberry Pi, dedicated SDcard players) but most sources will either output USB (like a PC or laptop) or S/PDIF coax (a CD or DVD player) or Toslink. We can supply a card for interfacing one (or more) of those sources to Abbado's I2S input. A CM6631A-based card for USB input used to be the premium choice as it operates under 'async USB' and offers up to 192k sample rates. However since I upgraded my PC to Win11 I have met issues with the driver, Win7 worked fine though. Async USB has the lowest jitter however given it operates under high-speed USB it needs a ~USD20 isolator module to protect your DAC and amp from common-mode noise. A PCM2706-based interface has the advantage of only needing a $4 full-speed USB isolator and occupies the bargain basement slot for USB interfaces. You'll not get any sample rates beyond 48k with this card, but for a NOS DAC no higher rates are needed. For S/PDIF inputs, the board we recommend handles both coax (two inputs) and Toslink. Further, it has a switched I2S input - this can accept I2S from the USB source. A single pole switch acts as source selector, cycling through the inputs. An OLED screen is an option to indicate the selected input. This board needs a 5-12V supply, so it is fine being run direct from the DAC's 9V rail.

Third you'll be wanting some output sockets, typically RCAs so you can connect your finished DAC to your amp or preamp. We can supply these and we also have a PCB to mount them to make outputting Abbado to your system easier. XLRs would be the recommended way to output in balanced mode.

Lastly, and this is obviously optional for a DIYer, is a case. We haven't supplied cases in the past because they're so heavy (i.e. expensive to ship).

USB CM6631A card examples : https://www.aliexpress.com/item/32874113831.html www.aliexpress.com/item/1005004083748180.html
PCM2706 USB-> I2S interface : https://vi.aliexpress.com/item/1005008112740281.html
USB isolator, full speed : https://www.aliexpress.com/item/1005001369085297.html
USB isolator, high speed : https://www.aliexpress.com/item/1005001379930133.html
Multi-input S/PDIF card : https://www.aliexpress.com/item/1005002923079600.html
Coax/Toslink S/PDIF card : https://www.aliexpress.com/item/1005002772984954.html

Do I need special tools to build and test my Abbado kit?

You'll need some fine diameter solder (0.3mm is recommended), a temperature controlled soldering iron with a fine tip bit and a pair of tweezers. A magnifier comes in very handy but that depends on your eyesight. Desoldering braid is helpful for correcting mistakes. Abbado comes with many of the smaller parts already soldered down (most by machine). None of the parts to be soldered are microscopic (the smallest is 0805) and none of the ICs has pins closer together than 1.27mm. For testing you'll need a DMM (digital multimeter) which is able to read both Volts and Amps.


What's supplied in the kit?

A picture of the kit contents can be found at the bottom of this post, it contains the pre-soldered PCB plus all the components that mount on it (resistors, caps, inductors, ICs etc.). You need to solder DACs, logic, regulator and discrete transistors which are SMD parts plus various through-hole components. Input, output and power are supplied via 4pin Molex-style headers, we supply the mating half with crimped wires to these too.


What, if anything, is unique about Abbado's design?

Commercial NOS DACs typically have minimal filtering after the DAC chip itself whereas Abbado has a fairly steep (5th order) low-pass passive filter which also provides some NOS droop correction. This LC filter improves dynamics and makes the aural picture more clearly defined with acoustic instruments having a well defined position in space. Passive filters like this are extremely difficult to implement using off-the-shelf inductors as no commercially available ones have sufficiently close tolerance. So Abbado's inductors are custom, hand-wound. Having a passive filter prior to any active analog stage means the discrete buffer no longer 'sees' a step waveform out of the DAC chip, rather a continuous signal. Abbado's DAC chips are 'multibit' but they're not strictly speaking 'R2R' as internally they use no resistors. Instead, capacitors are used as elements in the DAC which have their charge constantly refreshed (similar to the DRAM in your computer) to compensate for any drift. By paralleling 16 of these devices and running them at higher current levels than typically used, the noise floor is considerably lower than with a single chip - this translates in practice to a 'warmer' sound where the acoustic ambience captured on a recording is more easily perceived. In order to achieve retrieval of these low-level ambience cues, the DACs' power rails need to be extremely clean and this is achieved through use of a pair of discrete series regulators fed from an IR LED derived reference voltage.

Hi all - I'm beginning to build some Overnight Sensations. I'd like to post my progress in the right place. Is there a dedicated area for speaker builds?

I need to make space and get rid of some 300B tubes. All tubes are in good working condition and were tested with a curve tracer. There are some nicely matched pairs!

Shipping from Switzerland to anywhere in the world.

• 300B: Svetlana "winged C" (used only for testing), TJ Fullmusic mesh plate (light use), Electro Harmonix (used only for testing)
  Full test data and availability list is available here: https://mbrennwa.github.io/curvetracedata/300B/index.html
• 32B: AVVT (light use, 300B substitute but with higher power / voltage limits, built like a tank)
  Full test data and availability list is available here: https://mbrennwa.github.io/curvetracedata/32B/index.html

Please consider the following ballpark prices when suggesting an offer (see post #6 below):

• TJ 300B and Svetlana winged-C: CHF 250 per piece
• EHX 300B: CHF 100 per piece
• AVVT 32B: CHF 300 per piece

Hi,
I have a Tanglewood T6 acoustic amp on the bench with noise problems around the effects section.
Managed to trace down the problem down to U201 /RST Input (CS5340-CZZ) Analog to digital converter. Shorting C222 gets rid of the noise but turns off the amp effects, since /RST input is at low level, of course.
I removed C222 and R201, and the noise was still present. However, with those componentes removed, when I tap R210 leads with anything metal (a multimeter probe, screwdriver etc) Noise goes away and the amp works as expected.
What do you guys think could be causing this? Replaced R201 with a jumper and C222 with a new cap, but the problem remains.
Thank you for your help.
Best regards,
Fran

Want to buy new or used in working condition AT&T 1261AAC optical transmitter.

I have just bought a used Technics amp which has a switch next to the speaker terminals giving the choice of 4-6 Ohms or 8-16 Ohms output. The speakers I intend to use with this amp have a stated impedance of 4-8 Ohms. Which output on the amp would be best to use. Many thanks.

A few people have asked about wiring up a dual mono amp. There are separate power supplies and lots of opportunity for cross channel ground loops and ordinary 'classic' ground loops as well.

Here is a scheme that should allow a dual mono amp to be wired up that is quiet - ie no hum.

The trick it to ensure that there is one and only one connection between the two amplifiers, and that is accomplished by bonding the input connector signal grounds together.

The wiring scheme uses two ground lifters, although you could cheat and just lift one of the amps, and ground the other directly to the chassis, but I suggest you just spend a little extra effort and use two ground lifters.

A major issue here, as in any DIY amp, is safety. Kindly note the chassis (assumed to be steel or aluminium) is bonded directly to the incoming safety ground (earth) on the IEC receptacle. You cannot under any circumstances omit this connection - it is the most important connection in any amplifier. Using the ground lifters, the two amplifiers and their associated power supplies 0V then float +- 1.4V around the safety ground (earth). For the ground lifters, I always recommend you use a decent 35A 400V bridge rectifier - details in the presentation.

For the transformers, use a Toroidy (based in Poland) audio grade device with a GOSS band to minimize the radiated mag field, or if specifying custom devices, ensure your order your transformer with a GOSS band. An interwinding screen will also help to minimize mains conducted common mode noise.

One final point: do not mount your input RCA connectors on opposite sides of the rear panel. Mount them next to each other in order to minimize the inter-channel loop areas - again, details in the presentation.

🙂

Hey everyone! My name is Alex and I'm into audio electronics, especially building and tuning amps and speakers. Recently got interested in tube amps and Class D solutions, as well as experimenting with homemade speakers. Here, on the forum, I hope to find inspiration, useful advice and like-minded people with whom I can exchange experiences. I will be happy to participate in discussions and share my projects!

Hi everyone , my JVC BR-S611U professional SVHS vcr vu meters don’t register signal when I try to record audio from XLR line puts otherwise it does record and playback the the audio very well . The strange thing is when mic inputs on front panel are used you can see the vu meters moving and you can hear the audio from the built in headphone amplier in both left and right channels also you can see the vu meters moving when you play back the recording you just made from mic inputs and audio from headphone amp as well the audio from line output through a external pre amp but when you try to record from audio from line inputs the signal dies not reach the vu meters and no audio is heard from the headphone amp and as mentioned above apart from this you can still record and playback the audio . What might be causing the problem ? I have the service manual for it . I purchased it used . It’s in very good condition the sound and video quality is the best I have ever seen from a vcr and this things weighs 50lbs 🙂 any kind help to trouble shoot this problem of why the audio signal is not reaching the vu meters and built in headphone amp when line inputs are used will be greatly appreciated! Thanks 🙏

hello , first at all , thanks for all precious informations we can find in the forum.🙂

I hesitate to build new cabinet for my woofer ( Xover = 500 Hz) , in order to reduce vibrations.
I found lot's information about the panel material , thickness , bracing , damping.. but nothing about the constrain we can apply on the panel during the cabinet construction.
Let me give you an example :
Consider we use a bracing , but the size is a little bit bigger ( or smaller) on the middle on each 4 sides , ( 1 mm for example).
So , the panel fixed on the bracing will support a flexion... based on my feeling , the panel frequency will increase.
Do you have any experience about this ? Is there basic theory about this ?
I hope my explanation is clear.

Thanks in advance !
Joel

I was always in love with good music and quality sound but never had the chance to build something interesting. I recently got a Cambridge p40 mk2 and a Kenwood kr 4600 which I want to fix and have them for hifi setup

Hi, im not exactly a new member per say. My former account is donovas and i've been a heavy lurker/light contributor for many years. My email has been deactivated hence the creation of this account. Anyways, i feel good to have a voice again and here is to many more years of learning! Regards, Eric

I've tested and listen to just about every concievable passive potentiometer (volume control), Bournes, Alps Blue Velvet, Alps Black Beauty, Penny&Giles, Dact Switched resistors, and transformer (TVC) based volume controls.

Nothing has equaled the transparency and dynamics of sound than that of a series/ shunt LDR arrangment in the attachement, it has no contacts in the signal path, I believe that is the secret.
The only stipulation that all these passive controls including the series/shunt LDR need I believe is,
1: Low source impedence (cd player) <1kohm
2: High input impedence (amplifier) > 33kohm.

Cheers George



8-3-2015
To explain a little the 5 photo attachments.

1st: Is the basic led/ldr and how it works in the Lightspeed Attenuator, it mimics a 10kohm series shunt logarithmic potentiometer.

2nd: Is the Lightspeed Attenuator stereo version, complete circuit diagram, note how the signal goes through nothing but one soldered resistor, no sound robbing light contact of a metal wiper on a resistive track in a volume control (potentiometers) in the signal path.

3rd: Is the same but a dual mono, good for room or system imbalances, (for some reason owners of both say the dual mono has the edge sound wise) I believe it's the fact you can precisely centre the image regardless of recording or environment influences.

4th: Is the buffer Nelson Pass designed a few years back for the Lightspeed Attenuator (later to be known as the B1 Buffer) for it to be able to drive low input impedance amps of less than 33kohm.

5th: Is the $30 Kemo M087N led tester you can get on Ebay. With this you can quad match your own set of NSL32SR2S(sorted) Silonex led/ldr's you'll need get about 15 pieces to get 2 sets of quad matched led/ldr's for two x stereo Lightspeed Attenuators. So go halves with a buddy and you can have one each.
Match the LDR resistances using a DMM, powering the LED from 1mA to 20mA, give them time as they need a few minutes to warm up.

PS: You can skimp on the cheaper NSL32SR2 but you have to buy almost twice the amount, as their low resistance is not as low and constant, they cannot get to quietest minimum volume level as the NSL32SR2S (sorted) can.

Cheers George

Priced to go. Shipping extra from Atlanta, GA.

(3) RCA 807 - Re-boxed. Nice tubes. $12.50 ea
(4) JAN 6080 NOS - original cartons. GE & Sylvania $15 / ea
(2) JAN 829-B (1) Westinghouse; (1) RCA. Re-boxed. Look new to me. $10 / ea
(1) Chatham 6336A (gently used?) $20
(1) JAN 1424 NOS in original carton -- WWII vintage? $10
(1) RCA 6JB6A Compactron NOS in original carton. $ 15
(1) Olympic 6KG6 / EL505 NOS in original carton. Made in Holland (Amperex?) $35
(1) RCA 6LF6-6MH6 NOS in original carton. $30
(1) Sylvania 6LF6 NOS in plain carton. $20
(1) Sylvania 6LB6 NOS in plain carton. $15
(1) JAN-CHS-6L6GA (Sylvania) Smoky glass. Re-boxed. $12.50
(1) Bradford 6HF5 NOS in original carton. $15
(1) Zenith 6LR6 NOS in original carton. $ 22.50
(1) RCA 6JR6 NOS $20
(1) RCA 6JS6 NOS in original carton. $20
(1) Sylvania 6DN6 - Looks new? Re-boxed. $10
(1) RCA 40KG6 used (untested). $10
(6) GE 6AS7GA NOS in plain cartons. $5 / ea.
(1) Raytheon 6KD6 used (untested). $10
(1) Phillips 6LX6 NOS in original carton. $30

By way of background, I've been intrigued by some of the very simple amplifier circuits presented here, and have wanted to explore quasi-complimentary designs for several months now.

Inspiration for this project has come from Gareth (TGM lineup), Hugh (AKSA-55) and Carlos (original DX amplifier). I had originally planned to assemble Quasi's Nmos200; however, difficulties procuring boards has left me with a bag of IRF840 MOSFETs and nowhere to turn!

The schematic I present is as simple as I can possibly make it, without comprosing it to the point where it is just a giant oscillator. If you can think of any way to reduce the parts count further please let me know. Likewise, if I've omitted something essential for function or stability I'd like to know too.

I know there are 101 ways I can make this 'better': CCS on the LTP, degen resistors, bootstrap or CSS on the VAS, RC filters on the rails, etc. For this project I want to keep it as simple as possible and then my next project will be to embellish this circuit with some extra features.

Please let me know if there's anything I've missed (noting my Keep it Simple design ethos) and check my R values.

Next step will be to prepare a board layout and send the Gerber files to my board house.

Edited 30 September 2016:

Please refer to the post #1384http://www.diyaudio.com/forums/soli...mentary-mosfet-amplifier-139.html#post4844098 for the latest circuit:
http://www.diyaudio.com/forums/soli...mentary-mosfet-amplifier-139.html#post4844098

I would be grateful if anyone can explain why the DF1704/6 filter chips need to have the bit depth defined for left-justified input formats. The options available are 24 bit left-justified, 16 bit I2s and 24 bit I2s. Does truncation take place if 24bit data are input to a 16bit I2s setting?

Hello all!
I recently interested in buying a tube preamp but the output impedance is very high, it has 5000 ohm.

Unfortunately, the load impedance of my system is around 10K as the input impedance of the active subwoofer and power amplifier is 12K and 100K respectively.

Would it be any problems regarding impedance matching issue?

Thanks!!

I have Apogee Duetta speakers,see the attachment

In my Duettas bass foils are broken, thinner ribbon plays the highs

In my Duettas high ribbons are ok

Original crossover was 500hz at 6db/oct

Ribbon for the highs plays better, last longer, if its crossed steep at 1khz

I dont like these style dipole speakers, too many variables with interaction with the room

So i want to make the highs ribbon part directive, narrow directivity and close the back

The high Ribbon is 1,3 meters long and i am wondering about cone driver spacing if i make synergy horn

So plan is to make two way tall synergy horn and play with cone drivers from 200hz to 800hz/1khz
And from ~ 1khz the ribbon can take over

I have 15 inch bass bins that can play 30hz to ~ 200hz.

In a normal synergy horns midrange driver spacing is pretty straight forward...

if i place the cone drivers same way as in normal synergy/meh, its a lot of drivers 🙃 3 inch cone drivers divided to both side, 1.3m tall....

Some people have repaired apogees by replacing the bass foils with cone drivers, see the attachment

So some ideas:

Red circles are the cone drivers placing examples in the pics, idea1, 2, 3...
.. unlike on the pic from the ribbon horn idea, the horn is of course closed from top & bottom, made to a horn

1) make a horn for the high ribbon only, close the back.
Use repaired style cone drivers from 200hz to ~ 800hz. Cone drivers without a horns

2) make synergy horn, like mentioned before, lots of drivers needed

3) make synergy horn with wide cone driver spacing

4) make synergy horn so that the cone drivers are only in the middle of the 1,3m tall ribbon, at the level of listening position

Any comments and advises welcome!

Trying to get my amps as clean as possible I seem to run into the same noise floor issue every time. On 2 channel amps that share the same power supply I get an increase of the noise floor by 5-15dB when I connect both channels to the amp. I have tried all the groundloop fixes I have found on here and it have helped significantly but the issue is still there. I also have a few dual mono amps that don't have this issue and I am starting to think this might be unavoidable given a shared PS.
I've attached a REW dump to illustrate the issue and looking to understand if its as good as it gets with shared power supplies or of I should keep chasing a fix?
It's the same with multiple amps and sources so not just one amp or source.

A restaurant has 4, full range, 8ohm sealed speakers attached to a stereo amplifier. (2 on each channel). Against my advice the owner paid me to install a passive subwoofer. (6 ohms).

Here's the thing . . . The full-range speakers bottom out at 100hz (I'll assume Fs is around that frequency). The sub has an Fs of 50Hz.
Will the differing frequencies of high impedance offer any protection?

I did the job. I told him I was not responsible, and not to turn it more than 1/3 of the way up.

I know 4 caps would negate the danger but he doesn't want to pay the extra.

Ironically, there's an abundant cheap solution for this kind of installation.

On another forum I came across mods for a Michell Gyro/Orbe turntable, replacing the stainless steel ball bearing by ceramic, plastic, changing the suspension turrets to use rubber o-rings (like on SME turntables) and mods for the motor etc.

What got me thinking is changing the power supply for the motor, which I believe is a Papst 24v? motor. My power supply is perspex box with 2 transformers but it should be possible to build a quiet DC supply, amplifier and a PIC to play a digitised sinewave. A second sinewave albeit at a higher frequency could be used for 45 rpm so no need to move the belts on to the larger spindle.

I sure something like this has been done, the part I'm lacking is what voltage is required by the motor, (I don't understand why my power supply has 2 transformers). Hopefully someone can point me in the right direction.

Hi,

I am building a subwoofer enclosure for a 21" driver and need a slot port that is bent once to get the total length for the tune (30hz). But I am wondering at what conditions require the port to be rounded at the elbow as opposed to a 90° join?

I have modeled in win isd and with a port area of 1500cm2, i have quite a bit of area to avoid chuffing and turbulence. Modelling in win isd gives me a port velocity of 9.5m/s at max input power (likely at a frequency i will eq out anyway, so more like 8m/s at a realistic frequency..).

My question is whether this is enough to avoid any chuffing or major turbulence effects that will affect the sound if i make my port with a 90° bend as opposed to rounding the elbow of the port by cutting the corner on the turn to be 45° (and mirroring on the other side to maintain consistent port area throughout the bend). I assume i am fine to keep it at 90° with a low-ish port velocity, but wanted some advice from someone who has built something similar before i glue up and going back becomes a major pain in the...

A cursory Google search mostly lists posts for round ports and home audio applications but as this is a PA speaker with a beefier driver pushing out more air than a home audio sub, i was wondering if the community here could advise me.

Thanks 🙂

Selling these as I managed to get a pair of the 'R' coaxes. Honestly I didn't hear much change between the two.

I should have the trim rings somewhere but as of this moment they come with these baffles. I used them like this open baffle.

£100 plus shipping, which shall be at cost and packaged very well. The baffles actually will help with their safety as they are flush in there.

I receive mails from AV Nirvana although I don't have an account over there and NEVER asked to send me mails.
There's a link in the mail to unsubscribe but it returns an error.
Filling the contact form asking to unsubscribe me also returns an error.
Any help appreciated.

Hi all. I'm a beginner to multiway speaker design. I hope to start my first project soon when I'm ready.

Here's a simple 3D print that hold 4 quantity AmyAlice filter boards to be used in a dual rail PSU setup. Very simple design, but works well.

This thread was started to break off the Semi-Inductance (AKA Lossy Inductance) calculator from the behemoth Hornresp thread.

=================================================
Purpose of the spreadsheet:
Import free-air impedance data files and determine the parameter values for the advanced semi-inductance model to accurately define the blocked impedance of the driver. Once the blocked impedance model has been properly defined the driver mechanical and electrical Qs are then calculated, taking into account this blocked impedance. If Vas is not already known, a second impedance file can be loaded in to calculate it. The second impedance file should have the driver either loaded in an undamped closed box, or with mass added to the driver cone. Once Vas has been entered or calculated, the remainder of the TSP(Thiele/Small Parameters) can be determined. However, it is not required to know Vas if all that is desired is to determine the parameter values for the advanced semi-inductance model.

Software Requirements:
The spreadsheet was developed for use with Microsoft Excel 2007 or newer.
The following Add-Ins must be installed and active:
- Analysis TookPak
- Solver Add-in

Supported impedance data file formats:
- Tab delimited
- Comma delimited
- Space delimited
- ARTA's binary impedance data file format used by the LIMP module, *.lim

Modeling software that supports the Semi-Inductance model:
- Hornresp
- VituixCad
- SoundEasy

Calculated Semi-Inductance parameter data for some woofers:
Thread for Drivers with Semi Inductance
Data-Bass-v2-Drivers (see individual driver pages)
Data-Bass-Forum (Semi-Le_Calc discussion and download)

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


Version 1 of the spreadsheet calculator was posted here: Hornresp Post#8506

Version 2 is attached below.
- Added capability to import 2nd impedance file to calculate Vas
- Supplemental parameters now calculated (BL, SPL, Mms, Cms, Rms)
- Added blocked and motional impedance plots
- Added driver parameter export file
- Updated name of the FDD model in the Hornresp driver data export
- Corrected bug in Hornresp driver data export for Xmax
- Added Links TAB
- Added Notes TAB which includes list of references
- Expanded content of the Directions TAB

Version 3 posted here: Semi-Le_Calc Post#30
- Added capability to calculate and export FDD model parameters if using added-mass method
- If measured data does not extend at least 2 octaves below Fs, pop-up window provides recommendation for achieving good convergence with the model
- Directions added for installing required Add-ins along with checking and auto-activation features for English installations of Excel
- Fix for VAS Calc issues with some versions of Excel
- ASCII file import improved to handle leading spaces
- Le(1kHz) calc now uses model data, if measured data does not contain phase

*******************************************
Brian Steele has added a page on his website concerning use of the semi-inductance impedance model.
The latest version of the spreadsheet calculator is also hosted on his website.
The Subwoofer DIY Page

Claus Futtrup, co-author of the Semi-Inductance AES papers, has a personal webpage with additional background information and timeline on the development of the Semi-Inductance and FDD models.
Scientific papers


Related links:
Inductance Cancellation Techniques
Hornresp Post#8228
Hornresp Post#8252

Hi, just got ahold of a nice NAD C545BEE cd player. It works perfectly using the remote control. But the front panel buttons are not responding. None of the buttons work.

Looking for insight on fixing this issue.

Hopefully someone has already fixed this issue on this or a similar model NAD.

cheers,
Luis

WOW there was a lot of intererest in the Heathkit i posted last night, so I have decided to let this one go also. came from an estate sale a while back. it is a BRAND NEW OLD STOCK kit. complete with all parts etc. OH the joy of building your very own heathkit!!!!

***Note, last picture is from the web to show what it would look like built.

I will do the same $125 shipped in the USA, worldwide extra

This might have been asked before but does anyone know?

I know some ears dislike metal tweeters, for whatever reasons, too hot, metallic sounding, ringing in their ears whatever. Then theres others that think soft domes are too dull, flat sounding, lifeless whatever. Tweeters dont seem to change as much as bass drivers and some of the same ones have been around for decades like the Scan speak D2010 for instance. These are actually a tweeter which I think sounds as metallic as I've ever heard from a soft dome, and they are still used in modern designs in the mass production market as well.

Anyone know of any other popular ones that lots just seem to agree on just sound good? Are there any which have a reasonable price as well? Would like to experiment more with different tweeters. And which is the best value for money to performance ratio as well?

I want to try out this preamp from Aliexpress but am not sure what they mean by testing the voltage at the points indicated. If the board already has a transformer built in and is delivering 18v--what is there to test for? And why would they create a break in the circuit with pads that have to be manually connected? images of the board and the schematic are here:

https://www.aliexpress.us/item/3256...gvDM28hl&utparam-url=scene:search|query_from:

Right now I have a 3 way system consisting of SB34, AC130F1 and 27TAC/bg. I am thinking of going with the Satori Textreme tweeter. My thinking is that the Textreme and AC130F1 are similar materials (composites) and would probably integrate better than the current set up. What are your thoughts? Am I misguided?

Hi,
where can i found the mica insulator for TO-264? I have this mica here ( see picture ) but i think it is not correct. thank you! Maxpou

Re-capping a spare 1200 I had and found the ground trace between C108 and C112 overheated, lost its top coating. In my 35+ years of working on these I’ve never seen this issue before on the boat load of 1200s I've dealt with, even the few with bad AN6675 motor drive ICs. This pictured PCB is out of a properly functioning unit when I pulled it. However, it was purchased second hand with unknown history. The whole PCB looks to be untouched and never been worked on. The surrounding electrolytic caps all tested ok.

Anyone ever see this issue before?

Hi all,

To my knowledge, the narrower baffle will provide a better image of sound. However, there are some designs that are likely to be considered narrow baffles, despite the full-sized enclosures. For example, the old ADS speakers model LXX30 series; here I'll use the L1530 as an example.

As can be seen, the midrange and tweeter of the L1530s are mounted on a small baffle located at the edge of the cabinet.

I'd like to compare the cabinet shapes of the L1530 and L1590, as depicted in the attached.

1) IF EVERYTHING, including the drivers and crossovers, is the same, which model will give a better image of sound?
2) In my view, the L1590s perhaps give a better image, but how about if we change the L1530 to the flagship L2030? The L2030 has four midranges installed in a vertical array. Hence, could it compensate for the destroyed image and result in a better image than the L1590?

Hi all,

Here to build a 4x th18 and synergy rig.

Hi everyone, names Morne, from South Africa, I'm a fitter by trade and an audio enthusiast, currently busy with a small project, need some advice! Thanks

Hi, I'm new here. 50 years old and I'm an audio enthusiast, loudspeakers and amplifiers, now I'm working on my second amplifier projec

Looking to gain more knowledge about active crossovers

I have 2 Antek AS-4445 toroidal transformers for sale.
$sold each

The 400VA toroidal audio power transformers have static shield between primary and secondary coils to improve the isolation and noise interference. They are specially designed to work on all standard 115V or 230V at 50Hz or 60Hz. These transformers have heavier gauge wires than the normal requirement to avoid the copper lost during the full power output. And they also have the magnetic shield around the outside to reduce the magnetic leakage. The dielectric test is more than 3500V in between primary and secondary coils. In most of the cases, this transformer can be output 20% more power from its rating at 60Hz power source without any problem. This transformer comes with 1 rubber pads and all mounting hardware.

• PRODUCT BRIEF​

• Weight: 9.0lb
• Dimensions: 5.1" d x 3.1" h

ELECTRICAL CHARACTERISTICS​

Hi everyone I am Mica from serbia I like to build and thinker with speakers and audio and i dont like to waste stuff like speakers that look good quality and i am a dj and thats why I joined this forum. 🙂

...from a long time lurker, who is about to re-start a hobby, hands on.

Hello everyone!

Feels a bit odd writing here after years of mostly (mostly? what else did I do??) reading. I haven't been active here as a member, but I did learn quite a few things that I wouldn't have otherwise.

So, it's only appropriate for me to now say thanks to all of you, who have shared knowledge, advice and flame wa... erm... passionate opinions here over the years, for others, such as me, to read and learn from.

I'll try to give back a little now and, well, along the way also ask a bunch of questions and propose all kind of ludicrous projects.

So... thanks everyone again and see you around...

Not sure if anyone has a spare/scrap UPL laying around.
I have a UPL66 (no front lcd and buttons) and would like to convert it into a regular UPL. So, I would need the front panel, LCD, etc. Mine is also missing the digital option and I would like to add that if I can find it.

And of course I'd like to add UPL-B1 but I seriously doubt I'll ever find that!

Let me know what you have, I'm located in New York.

Until now I have been performing simple LTS simulations for RIAA preamps, which is what I'm involved now.

I wonder if there's someone else doing something like this, or has done, so I can add those experiments to mine.

The ones I have been doing involved noise, frequency response and THD at several frequencies. Due to difficulties in finding proper discrete active parts, like FETs, I have more or less limited my sims to two stage preamps, with single or dual low noise ICs, FET and bipolar types, passive and active ones.

The next point is what you will use to power it with. What regulators?

Some years ago I opened a similar proposal, and the discussion was very much centered on what loads to use.

Carlos

Browsing donhighend and saw this link to some interesting new woofers and tweeters from a spin off company by the Sica founder, claiming Fibonacci principles applied to deliberate erosions to the cone through some new patent (will try to find it)

The 8" looks interesting, well they all do.

https://rsspeakers.it/products/w-220-50-fibonacci-2/

Think I found it https://patents.google.com/patent/IT202100017741A1/en

Claims:
I. Loudspeaker membrane or part of it in which superficial incisions or abrasions are made on the front surface, to form patterns capable of distributing the resonances of the membrane in the best possible way, minimizing distortions and linearizing the frequency response; II. Membrane or part of it as in the previous point in which the superficial incisions or abrasions are practiced only on the rear surface of the loudspeaker; III.Membrane or part of it as in point 1 in which the incisions or abrasions are made on both surfaces, front and back, according to figures which are not necessarily identical.

Pair of brand new Faital Pro HMF200 mid compression drivers. 2in exit.


Beautiful, elegant and natural sounding. Lightweight paper diaphragm that’s smooth and organic.
Must hear!

$650
Free shipping CONUS