Just finishing up a KT88 PP amp using dyna clone iron. It uses Pete Millet's compactron PP driver boards. Schematic here:

Push-pull driver board

The boards are built pretty much to this schematic.
My problem is that any feedback applied from the opt causes instant
oscillation. Both channels act the exactly the same leading me to believe I'm overlooking something simple. It plays well otherwise except the highs seem to rolled off a bit.
Thanks

I am interested in building th sb acoustics rinjani kit but i would have prefered a lover x over point than 3000hz. i then saw that the Rinjani Be version had a lower x over point at 2300hz. And i am wondering if i could use that x over but insted of the TW29BN i use the TW29RN insted. i know that different driver usualy arent interchangeble but i saw that Troel Gravesen are using those drivers on the same x over on many designs. Does anyone think that it is a bad idea and i should use the standard 3000hz x over with the TW29R tweeter?

I'm thinking to add the acrylic dust cover to my tube amp.
The amp is of "classic" design (with tubes and tranformers on top of the chassis) and cleaning it pisses me off more and more every week.
Fortunately, the cover itself can be made fairly inexpensively by the local company.
There are different ways to attach it to the chassis. I want it to be completely removable (not hinged). One can, of course, just slap the cover on top of (or around) the amp and hope it'll stay there regardless of cats and kids.
But are there some types of holders that can keep the cover from sliding? Some U-shaped things that can be permanently attached to the chassis and with slots wide enough to accept the acrylic sheet of 3-4 mm thickness?
Any other ideas are welcome too!

There is one thing in the live sound world i've never managed to get quite right and that's the top end. CD's seem like an endless world of options and possibilities, with limited modeling capabilities.



So with that, i'm currently building a set of slightly modified SMT 212's for testing. If they work the way I want, then i'll be adding a few more. I'm loading them with Lavoce WAF123.01 woofers, which have scary close parameters to the original SN-12mb's used in the cabinet. They will be bi-amped for mids and highs as well. Each mid/top cabinet will sit on a set of 90* coupled 40hz front loaded horns with 18lw2400 drivers. Modeled sensitivity of the flh's are about 112db @ 2.83vv. I have no way of testing the actual output but to the ears it sounds every bit as sensitive as modeled. If everything works and blends, then it will eventually be 4 of the 40hz horns on top of a single 21" tapped horn. and 2-4 of these cabinets will be on top of all of that.



Power levels will be 800w to each flh, 500w to each set of mids (for now). Once the addition of the tapped horns come loaded with 21ds115's, they will be 1.5kw each. The 40hz horns will be bandpassed 38hz to 120hz. Mids will be high passed at 120-140hz to i'm thinking maybe 1.2khz to 1.5khz. Once the addition of the tapped horn comes in then the TH will be 25hz to 80hz, flh's will be 60hz to 150hz, and mids will cross at 140hz.



Question is, what compression driver and horn would you recommend with this setup? I would like something that can play roughly 1.5khz and up, but also keep up with everything else. These will be used in small to medium local venues, and occasional outdoor events with 200-300 people.

I was highly considering the B&C DE250 coupled to the ME45 horn, but i have a feeling the rest of the rig is going to walk circles around it.

Some good suggestions would be excellent. And if you are already running the dual mids version of these cabs and can give feedback, that would be even better! Thanks in advance for all your help!

A little background:
These were good CD players in their day intended for DJ use so have features relevant to this i.e. cueing and ability to pitch bend etc
One issue though that has always bugged me was the sound quality from the DAC (PCM1700U-J) and as they only have analogue outputs you get the idea.

Having had a look at the schematics and data sheets of the DSP used (Sony CXD2500BQ) I believe it should be fairly easy to modify these to have a digital out.

Question is can I take the output of pin 60 off the CDX2500BQ directly or does this need to be buffered before going to a digi output RCA socket?

Of course at the moment pin 59 is going to ground which needs to be cut and a switch needs to be installed to toggle between on and off i.e. between GND and I believe anything above 0.7Vdd according to the data sheet.
Thing is it doesn't state a max, is 5v acceptable?

Thanks

on the attached diagram i have marked the + and - rail voltages.
Is there a reason they are different? (marked a)



also there is a realy high voltage 82.7v (marked b) that i cant work out how it gets to that figure given the surounding voltages


sorry if they are silly questions,but im trying to work my way back from the db LED board that isnt working, checking the voltages and getting 31v either side of this diode



the rest of the amp is working perfectly, its just this LED board that isnt working.


thanks 😱

Trying to try this TCXO in a cd player, And it seems to work well but only when connected to a 9v battery supply.
Connecting to 10v rail or dedicated 7509 results in TOC error

Any suggestions Please as to what i'm doing wrong?

Sorry in advance for a question with a possible obvious answer:

2 electrolytical capacitors in series, each rated for max 25 V, is it safe to apply 35 V at the 'outside' of these two capacitors?

If it is, is the maximum allowed voltage 50V?

I think it is but I am not sure. Thanks.

So my AT 440mla stylus met the hands of my three year old and was bent a good deal. I tried to gently nudge it back in line but now the thing doesn't even track.
At risk of ruining my records, I figured I'd replace the stylus, pronto.


Unfortunately the replacement styli are $30-70 more than I paid for the whole cartridge!


What would be a suitable replacement under $200? TT is an AR XA with a stock arm and generic DJ style headshell.


FWIW I liked the AT 440 but found it a bit sibilant.

Hi all
I have a Laney lc30 and when I got it the reverb was faulty. I metered the tank and the output was open circuit. I have just put a new one in and it still doesn't work. Any ideas thanks

For about 10 years now I've owned a Luxman PD121 turntable, which I've never gotten to a point that I feel it's performing to it's potential, and every time I've tried to get somewhere with it, I end up poorer and disappointed.

The turntable came to me with a problematic Denon tonearm on it that is way to loosey goosey and not a good match for the cartridge I already had that I've also not had much luck in pairing with something to make it live up to it's potential, an Ortofon Rondo Bronze.

So, that leaves me looking for a solution to replace the tonearm that will pair nicely with the Luxman turntable and Ortofon cartridge.

I turned to Ortofon customer support for advice, figuring they would have a better idea of what would pair nicely with their cartridge. Their support recommended an SME 3009 tonearm as an option that would pair nicely with the cartridge, and a "most recommended" tonearm upgrade for the luxman turntable. So I picked one up. I'm quite unhappy with this recommendation.

The luxman turntable comes with a metal/plastic puck with slot that is easily removed and inserted into the base, to install a tonearm. I downloaded and checked all documentation I could find on the luxman turntable to see if that would offer any useful information on what tonearms to pair with it - it doesn't. Only gives information as to how to remove/insert the puck - no recommendations or information at all whatsoever on what to pair with it, or how, or how to go about finding a decent pairing. I suppose back in the day that was left to the dealers to deal with. Anyways, what I was expecting was a tonearm similar to how the denon works - a threaded tube that fits through the slot, with a nut to tighten from underneath. What I received is a tonearm that comes with a metal plate with 4 tiny wood screws, and a tool to determine the proper point on a wooden base to drill holes, and secure the metal plate with the wood screws. Mind you, I did do some research before making this purchase, which was recommended by Ortofon. And I have found multiple examples online, with pictures, of Luxman PD121 turntables with SME 3009 tonearms on them. It appears they're screwed in, as designed.....into the metal/plastic puck.

I knew enough to not expect a wood screw to easily go into my turntable base, so I carefully laid out where the plate would go, marked points with marker, got my drill, and drilled some pilot holes for the screws to go into. And I then carefully attempted to screw the plate to the puck, and carefully broke the heads off of 3 of the 4 screws in the process.

I then went to the hardware store, picked up an assortment of 3 different types of screws, and tried again - as there was wiggle room to slide the plate over and try again where I didn't have holes plugged up with broken screws. And on the 3rd type of screw I tried, I finally ran into success.

This is not at all what I had in mind for tonearm installation, so I'm a bit pissed at Ortofon for recommending a tonearm that is clearly not designed for my turntable, despite it having been installed by some in the past. But...after throwing money at one, one is motivated to make it work.

So, the tonearm does come with 2 different counterweights. This was important, as counterweight weight was an issue in the past. The Ortofon cartridge was clearly heavier than the Denon tonearm I had was designed for, and I had to add extra weight to the counterweight on that arm to make it work - which was, in my mind, a half assed modification to use it outside of it's designed spec that would prevent me from achieving the full potential of the products. This was a big reason I was on this path of a new way to half *** something into working. So, I put the big counterweight on, put the cartridge on, let the arm loose, and it flew into the air. Even with the heavy counterweight screwed all the way in. Clearly, this weight is too heavy for my Ortofon cartridge. Then, I go to the smaller weight. Attach it, and the tonearm is always weighed down by the cartridge, even when the weight is as far out as I can make it. It seems my cartridge is in a no mans land of too heavy for the small weight, too light for the big weight. I went looking on ebay for SME counterweights, and found plenty of examples of those 2 sizes sold by themselves, no example of another sized weight in the middle.

As upset as I am at Ortofon recommending a tonearm that doesn't exactly pair nicely or easily to my turntable, at least that's a little understandable....but for them to recommend a tonearm that clearly doesn't pair at all with their product, is just beyond excusable. I'm beyond pissed at Ortofon support at this point.

Meanwhile, I do have a signet cartridge that is much lighter than the Ortofon cartridge. So I decided to see if I can at least get that working with this. And I found once I got that balanced, even with the tonearm lift in the down position, the needle hovers over the surface! Ugh!

It does seem as though the piece that contains the lift can be adjusted down, although it requires a tiny star screwdriver to loosen the adjustment screw. But yet another sign that things are just not paired right.

I'm a bit frustrated as this isn't the first time I've looked for advice or help in turntable setup, and it seems while there are plenty of people that will speak to the importance of researching these things, and pairing things properly, to find that synergy among the equipment, no one seems to be able to give any specifics as to just how to do that! I've made great efforts to research these things, ask around, ask the professionals, find the documentation out there, download it, make what I think are informed decisions....and I end up throwing good money away on equipment that doesn't pair at all. It's beyond frustrating.

A piece of advice that's sometimes thrown out there is to sell it off and buy something else. But that's advice along the lines of, well, if you don't want to do it, if you can't handle it, if you aren't capable... That's not exactly the case here. I'm willing to put in the needed effort. This is a decent turntable, it should be able to be brought up to spec and made to work. If it sell it off, then I'll just end up with another turntable that will inevitably need maintenance at some point, it's not like I'm not going to need to figure out how to maintain my equipment at some point.

I feel like - the world is just filled with people that have little useful advice beyond vague suggestions, and the knowledge I"m looking to get is just being lost by a generation that is disappearing. And I don't want to let that happen. Someone needs to keep these turntables going, I'd like to at least keep mine going for as long as I need it.


So....that's my story, that's my current situation. I'm awaiting tiny star screwdrivers to try and further adjust the tone arm. Although I'm still out of luck for the weight issue with the Ortofon cartridge.

Is there anyone here that can offer some real solid advice or suggestions here? I'd like to get this turntable up to spec, and the Ortofon cartridge in use to live to it's potential. How should I go about doing that?

hi all

i just bought a i2s to spdif hat for RPI from aliexpress .it's a wm8804 based hat. the hat come with DC inlet and feed the power to RPI. i try to isolate the power of RPI and the hat by removing the gpio pin for 5v,3.3v and all ground. then feed both RPI and the hat with 2 external PSUs. then volumio and moode show error as attached. what did i done wrong 🙁 ? if anyone has any solution or resource please please let me know.

thank you so much.
Pu

I have been working on transforming a wired active HiFi speaker into a streaming wireless speaker.

Here's what I combined/my items:

• Arylic Up2Stream Mini v3 streaming DAC module: Wifi Audio Receiver with Multi zone Control-Arylic.com
  – arylic
• 230v to 5v converter, isolated: 3pcs 5v 1a ac-dc power supply step down module bare board Sale - Banggood.com, and another one I tried is: 3pcs hlk-pm01 ac-dc 220v to 5v mini power supply module intelligent household switch power supply module Sale - Banggood.com
• Active speaker B&O BeoLab 8000: Bang and Olufsen Beolab 8000 Active Loudspeaker System Manual | HiFi Engine

How it's done
I have the Up2Stream Mini as a WiFi receiver for the incoming audio stream. This module converts the stream into an analog signal. Via a cable this signal is going from the Up2Stream Mini directly to the audio-IN connector on the amplifier board in the active B&O speaker.

How it's connected
The 230-to-5 volt converter is used to get the right power to the Up2Stream Mini. The input (230v) is tapped from the 230v that goes into the power transformer of this active speaker. Therefor I looked for an isolated 230-to-5 volt converter.

Problem
Everything works perfectly, but one thing: noise!

• Situation A: When the amplifier in the speaker is on & no music is playing, a slight noise can be heard. But in fact, it's not a real problem, because only in a distance of 15-20 cm, that noise can be heard.
• Situation B: When the amplifier in the speaker is on & music is playing, the noise is amplified and can even be heard at a distance of 2 meters. When the music is stopped, the noise level immediately goes down (as described in 'situation A').

Question
Who can help with a solution?

What is your experience which rectifier sounds better? It been a few years and no conclusion was posted here. I know some Hexfred are reported to not sound good, my post is referring to good sounding Hexfred that are the majority. Either newer diode is likely a good upgrade to vintage gear.

A friend of mine asked me to have a look at his Sansui au-607 saying it starts to get noisy after listening for a while. If he turns the volume knob it apparently clears up, until it needs another turn.

Opening it up today for a first time look the interior is typically dirty . . . . dust, oils, bread crumbs, bug bits etc. also Left end of board photo shows the start of heat discoloration. The photo doesn't show most of the crud that has accumulated on the cool side of the board , especially down near the bottom.

The controls will take a bit more work to uncover but considering the dirt and age I'm wondering how far to go. I don't have experience with anything like these old Japanese SS amps and so no idea whether to stop at spraying some cleaner into the pot . . . . . or if attempting to do a better job for my friend by dismantling and cleaning this roughly 30 year old amp is wise or asking for trouble.
Any advice?
TIA

I am about to build a speaker system, based on 2 Audiotechnology woofers + 1 Scanspeak Berylium tweeter.
The Amplifier is Hypex FA123.

In order to block DC, Hypex recommends a capacitor in series with the tweter.
As I see it, Hypex is not the only manufacturer, who recommends this, although, I see it as a disadvatage, removing one of the main arguments for an active system: no cross-over components.

My question, is, how to calculate the capacitor.
Some recomends that the cross-over frequence is in the range of half of the cross over, used in the Hypex module.

What do you think?
The lower the frequence, the more expencive capacitor!!
Any alternative ideas?
I did not yet buy the Hypex amplifier.

Thank you in advance for your help.

I am looking for a source for Phono Preamp grounding post's. Looking for a new parts supplier that has a couple sizes/styles available.

anyone know of a source? Preferably USA based?

Zc

Hi , at all.
I finished an amp, with 390v at plate and -68v in 300B Electro Harmonix cathode with 1K resistor.
Only have 68mA current.
If i lower the 1K resistor to 880ohms , to increase current , but low the voltage to 64V and 72mA.
Could i have 80mA or more current with the 400V ?

Santiago.

EDIT: This was user error. I was testing the SMPS like I would test a transformer -- in AC mode 🙂. Everything is working as expected!



I just received my SMPS from AliExpress and while trying to check the voltage its output pins got short-circuited accidentally.

This model is very popular in eBay and AliExpress, and attached is its picture from the seller's listing.

This SMPS is supposed to be 300W with main outputs +/-24V, and I shorted -24 V pin to 0 volt. I am hoping it is still repairable.
Can any one guess what might have blown by short circuiting the outputs?

(I posted this also in diysmps)

Thank you so much for your help!

Have a 500/1 here, came in shorted outputs.

PS fine, drive with outputs out seem ok. Install outputs and as soon as rail builds drive to outputs goes away and low ohm light comes on.

Output inductor tested ok out of circuit.

Ideas?

I am considering producing composite radiused corner caps that you can assemble with regular MDF via glued joints. It would be nice to get a gauge of how much interest is out there from people that may want a set.

In structural terms they could have foam core or be ribbed. The idea is to make them in 32" lengths so they can be cut to length. Working out the most cost effective way to do this at the moment.

Anyone interested?

Hey all, this is my first post at diyAudio, so apologies if this is the wrong forum for this but it seemed most appropriate given what I'm trying to do.

I'm working on the second revision of a DSP-based instrument (guitar/bass) effects board, and while I understand the digital side of things quite well, I'm in a bit over my head as far as the analog parts go. I'm intending on using an ADAU1361 as the codec to get the audio data in and out of the DSP (an ADAU1452), and thus need to be able to properly interface the raw input signal from the instrument, get it into and out of the codec, and then be able to drive whatever comes after in the signal chain - an amp, another effect, etc. The previous revision of this board used a pretty simple opamp-based input and output, but I'm not sure how well it actually performed, and this is the reason for my post.

At the moment, the input side has the following goals:

• High input impedance, to avoid loading down the pickups of the instrument
• Unity gain; the codec contains a PGA with between -12dB and 35.25dB of gain so I can amplify the signal after the fact
• Single supply, as the entire board is 3.3V
• 20-20kHz low-pass filter, to keep things inside the audio range
• 1Vrms full-range input to the ADC
• Single-ended, going pseudo-differentially into the ADC
• Low noise; the source signal could be very weak and may need to be amplified significantly by the PGA

The output side I'm not quite as confident about, but is basically the mirror of the input:

• 1Vrms DAC full-range output
• Low output impedance, to drive whatever comes next in the signal chain
• Filtering? Not sure what (if anything) would be needed here that the DSP couldn't do itself
• Single-ended

The ADAU1361 codec supports both single-ended and (psuedo-)differential inputs and outputs, and I plan on having the input driven pseudo-differentially (to have it go through the PGA), and the output driven single-endedly.

Now, I can build up these circuits - opamp based, sallen-key topology for the filters, etc. - but I'm not really sure how to properly analyze them to determine ahead of time how well they're going to perform. I can build up the circuits in SPICE, and do some analysis, but I'm not really sure how to determine what the analysis is telling me or whether or not the changes I make are going to correspond to a better final result.

For the first iteration of this board, I used an input buffer/filter that I found from some bass guitar effect and the output buffer/filter as specified in the datasheet for the DSP (ADAU1701) I was using. As mentioned before it DID work, but sounded very tinny and hollow. Ideally, I want it to be as transparent as possible; there should be very little difference between having this in the signal chain (with the DSP just doing a pass-through of the input data to the output) versus not having it in the chain at all.

I'd prefer not to mess things up and have to respin the board, so any advice you all can give me on how to do this right the first (second?) time would be greatly appreciated. What properties should I look for in the opamps I'm using? What analysis should I do in the SPICE sim? How can I make sure that the design is going to behave correctly before I commit the design to PCB? I could potentially breadboard the input and output filters, but I'm not really sure how to properly measure that they're doing what I want them to do. I do have an oscilloscope and a signal generator, but I don't know what to measure beyond checking that the signal goes in and comes out biased correctly.

This schematic is what was used for the first revision.


Any suggestions or tips in getting this design up and running are greatly appreciated!

Roswell Pro Audio was founded by Matthew McGlynn, whose first entry into the pro audio gear industry was RecordingHacks.com. RecordingHacks provides detailed analysis and descriptions of thousands of microphones, as well as some of the most ambitious mic shootouts ever produced.

McGlynn's deep experience with hundreds of microphones over many years — learning how they're built, and why they sound the way they do — led to the formation of Microphone-Parts.com, a DIY electronics company that sells premium studio microphones in "do it yourself" kit form.

Roswell Pro Audio borrows from the research and development work done by MicParts, but takes its products in a different direction. Roswell's designs distill the various capsule and circuit combinations into best-in-class offerings that have won acclaim from musicians, home studio owners, and Grammy award-winning producers and engineers.

Roswell Pro Audio | DIY Microphone-Parts | Matthew McGlynn - YouTube

Hello all

I am working on a dual mono LM3886 power amp and need extra trafos
for theese two cards:

SSM2141 chip +5534 op amp output

Input balance signal, output unbalanced signal, suitable for system modification in which the front stage is balanced signal output, and the rear stage has no balanced signal input.

Product Name: SSM2141 Balanced RCA Conversion Board

Power amplifier board main board input voltage: AC15V -0- 15V
(main voltage can be selected within the range of AC double 12-18V)


How many watts an what kind of a transformer is recommendable ?
Is it best with one or two ?

Glad for answer, stay safe !

Hi All,

I am a total novice - I have built an F5 (I had a lot of help), and Aleph J (also with much help) and the F6 twice. Additionally, I built a Bottlehead 2a3 SET and a handful of tube and SS phono stages. All were totally paint-by-number affairs. Suffice it to say that I can take directions and execute very well, but I don't really know what I am doing.

I have two ACAs that I am running as bridged monoblocks (v1.6 with 24v supplies). They sound great, however, I prefer the sound of the amp in the true single-ended stereo configuration. It is just short on power into my 12 ohm speakers (they are listed at 97db, but I don't know if they truly are that efficient). Of all the solid state amps I have owned, the ACA sounds closest to a tube single ended triode (and I don't have to deal with tubes). I think I just like the way single-ended amps sound.

This got me thinking: would it be possible to build an amp using the ACA boards (basically the circuit) but with more powerful output MOSFETs?

Before you say "dude, just build an Aleph J" - I have built one... I actually prefer the sound of the ACA, for whatever reason.

I think with some help from the knowledgable folks on this forum, I may be able to build a beefy ACA by using more powerful output MOSFETs.

Objectives:

• Single box, stereo configuration
• Roughly 10 watts of Single-ended output into my 12 ohm speakers
• Use the existing ACA v1.6 boards without having to cut new traces or anything
• Keep it simple
• Safety, Safety, Safety

Assumptions:

• I will need a larger chassis with greater heat sinking (probably get the deluxe 4u)
• I will build linear power supply
• I can use the same JFETs and ZTX450 transistors in the circuit, but most of the other values will need to be changed to account for the more powerful output MOSFETs

So, the first step is trying to figure out which output MOSFET to use. I pulled up the MOSFET the ACA kit ships with on Mouser - the IRFP240PBF. From there I filtered by the case size (TO-247AC-3), N channel, Gate Source threshold voltage = 2V and VGS = 10 (I picked these because that is what the IRFP240PBF is). I began looking for other MOSFETs that had datasheet specs that were similar to the IRFP240PBF, but had a higher power dissipation.

I came up with the following list:

• IRFP264PBF
• IRFP460BPBF
• IRFP360PBF
• IRFP360LCPBF

The IRFP264 has the highest forward transconductance (which, I think, is the signal gain) and the lowest Rds(on). However, it's Qg -gate charge is the highest of the bunch (I think lower is considered better in this application, but I could be wrong).

Conversely, both the IRFP460BPBF and the IRFP360LCPBF looked like the closest match to the IRFP240PBF on the spec sheets, with the obvious exception being the Power Dissipation is much higher.

Does anyone have any thoughts as to which MOSFET is a good candidate for this project?

Hey Gang!

So I finally stopped procrastinating replacing resistors and pads that lifted off the PCB and went for it. I usually have very bad luck. So I watched a bunch of videos from guys that do a lot of PCB repair and learned a few things AND employed them. Especially using Antech sticky flux with desoldering braid. What a difference.

I was able to get things apart and then remove, and replace the resistors and adapt the leads to traces and Hot Glue the resistors in place to salvage the PCB. I had another thread about this months ago and several really helpful members also suggested using the KISS method. (Keep it SIMPLE... STUPID. LOL) Subwoofer Amp Help Needed! Original ProMedia 2.1

I thank them and despite the fear of ruining it, like usual, after much procrastinating, I did it. (I hope)


So, now to remount the Transistors to the heat sinks. Seems like a white Foam Tape is on the Chassis Plate that the transistors screw to. There was some powder when removing the transistors off the plate/foam tape heat sinks. (Pic below)

What am I supposed to use/do to make this reliable and effective. I've searched and maybe I'm using wrong search criteria, but I'm not finding the answers I'm looking for. Everything but!

Please point me in the right direction!!

Thanks Gentlemen!

Regards//KP

I am looking to get a mic so I can do some speaker design work, and am just about to pull the trigger but noticed someone mentioned a UMik1 doesn't have ability to extract phase the same way a mic like the Dayton EMM6 can, and that you need to do a workaround. Is this correct?

If so, is it more beneficial to have a calibrated UMik1 or an uncalibrated EMM6? Or both?

I just thought I’d drop a note (a long note) here about my recent experiences which I hope will help anyone who considers using solid wood as speaker cabinet building material. If you don’t want to read my story, you can go to the end and see my conclusions.

I’d like to start out by saying that I love working with solid wood; building entertainment units, shelves, and most of all speakers. I especially like working with thick slabs of heavy wood. It’s hard to explain but it feels like you’re carving and moulding your speaker cabinets instead of assembling panels. Which of course is nonsense, but I’m a tactile aesthetic kind of person; the kind of intolerable amateur woodworker who is always running a hand along a sanded surface and smiling. It makes me happy.

To be clear, I’ve got no beef with MDF or plywood – I have built two sets of speakers using MDF and one with ply – I just loved working on all the speakers I built with solid wood. I know the risks of building with a totally organic material like solid wood and I understand the extra care required in the treatment of the material, but I also appreciate that with care you can achieve furniture grade results. And my wife appreciates it too. Which is one of the reasons I can get away with filling our house with big speakers.

The speakers which this story is about are 1.45m tall floor-standers made of 31mm panels of solid Pacific Maple which give a lovely gold/tan/red colour in the grain. The back panel and bottom panel were made of a sandwich of ply and MDF because I had to cut costs somewhere. Wood is expensive.
The basic details of the speakers are below for those who are interested:
• Tweeter: Scan-speak D2905/9900
• Mid = Eton 7-360/37
• Woofers = 2 x Scan-speak 25W/8565-01
• Net internal volume of 133 litres with rear firing port tuned to 22Hz
I won’t go into the crossover details here because there were seven revisions since the original crossover design… I like to tinker.
It had third order filters with some impedance equalisation, mid smoothing and tweeter attenuation.
I was younger back then and I make no apologies for loving bass that went boom. Yes, I know it was wrong: I measured a 6dB peak around 50Hz – 60Hz, but I left it and I loved it! I listened to a lot more dance music back then.

Anyway, I finished building the speakers in 2008 when I was living in the Crows Nest area of Sydney. Crows Nest is surrounded by water inlets, dripping forests, is reasonably close to the beach, is at sea level, and not least of all quite close to that big harbour of Sydney. All those points add up to humidity levels between 50% and 95% every day – hot or cold. Which is fine because the wood I used was purchased from a supplier in the local area. The speakers lived quite happily in Crows Nest for seven years without any sign of wear or damage. It seemed like they would be upsetting neighbours for decades to come.

This time last year, some big changes happened in our lives and we had to move to Canberra. Canberra is an inland town, surrounded by cleared farmland, is at altitude, and has no natural waterways. There is no humidity to speak of whether it’s hot, cold or even raining. Canberra, although being a lovely town, is practically a desert.

After about three months of living in Canberra I noticed some cracks appearing in a few of the joints of the speakers. A month later the cracks had broadened and a few more had appeared in other joints. Almost all the panels had cracked in some way except for the ply/MDF back panel.

You can see in the picture the dark line where the front panel is pulling away from the sides. The top panel is also separating.

I found a local timber yard and furniture maker called Thor’s Hammer (great name!) which was recommended by friends who had bought furniture from them. I spoke to a bloke there named Gerry and told him about my situation. He said, “Yeah, that will happen. You should expect the moisture content to drop by about 12%, which means a lot of shrinkage.”
I asked if there was anything I could do to stop the moisture loss like sanding back and using oil to seal instead of varnish or something. The wood was expensive and I didn’t want to start again. Could I strengthen the joints?
“Nope. It’s going to shrink anyway. The joints are probably fine. The best you can do is leave it another couple of months to make sure the wood has reached the point where it’s as dry as it’s going to get, then sand back the varnish, fill the gaps with resin, sand back again, and use a flexible natural finish like oil.”

I had some time while I waited for the speaker cabinets to find their natural Canberra level of moisture and I figured if I was going to have to pull the speakers down, then I may as well tinker some more. I always thought the speakers sounded good (in all their versions), but the bass really was boomy with too much excursion. I’m older and …well … just older now and don’t appreciate the boom quite as much. I fired up Soundeasy and got designing. After a couple of months of designing and comparing options, I decided since the cabinets were already huge I could quite easily turn them into a transmission line.

I replaced the ply/MDF back panels with solid Pacific Maple like the rest of the cabinet. Sourced locally in Canberra. I took some more advice from Thor’s Hammer and left the lengths of wood inside to season for a month before joining lengths and cutting them into panels. This was also to find their moisture equilibrium.

Four months of repairing, woodworking, construction and a lot of sanding later, I have functioning speakers again. I used oil instead of varnish, which made the wood grain in the cabinets a little darker, but nicer looking. I finished a few months ago, but I let them settle in before I wrote this just to make sure there wasn’t going to be any more movement. So far, all good.

The only issue I have with the gaps now is my own mistakes I made with the resin. Otherwise it’s smooth to the touch (I ran my hand along many times), and they have a bit of a reclaimed timber look about it. From one metre away you can’t tell that there were ever any gaps.


As for the sound, this was my first attempt at a transmission line and it lead to a lot of tinkering… I was in heaven! I had my measurement mic out every weekend for months! I had some phase issues which resulted in a slightly unorthodox fourth order filter for the woofers and third order for the mid and tweeter which did the trick. I did a lot of experimenting and ended up with lots of heavy stuffing in the transmission line which seemed to have only a little effect on the bass extension, but did tighten it up nicely. I now understand what people mean when they say their transmission line has tight and clean bass. It really is something different to the ported and sealed enclosures I’ve built. It goes deeper without lots of cone excursion and kickdrums have a nice clean “thump” without the boom. That’s all the subjective remarks I’ll make.


I am very happy with the results. So, this is a precautionary tale but like all good stories, the main character learns a thing or two along the way and it has a happy ending.

In conclusion, if you choose to build with solid wood:
• Solid wood behaves like a live material – it expands and contracts with moisture levels.
• If you build with solid wood be aware that moving to a different climate may cause your panels to split or buckle.
• Source your wood locally and season it. If possible leave it inside your house for a month or two before you build.
• Don’t be scared off. There are ways to repair the damage from split wood, but not ways to stop it.

I’m sorry this ended up so long. I started typing and it just went on.
I hope this has been helpful to anyone who considers using solid wood. I intend to continue using solid wood.

AJ

Hi

I'm seeking some advice and any help would be much appreciated.

I have built a simple DAC that I am very happy with. The sound quality is excellent. There is just one thing that could be improved.

It has single-ended outputs that output about 3.2V peak to peak. These are directly coupled from the output stage, which is a differential amplifier (the INA2137) via a 33ohm series resistor (to somewhat protect against accidental shorting of outputs).

My issue arises when I have the DAC plugged into a mixing desk (an older Mackie model). It works fine until I power down the DAC, and then those channels start to pick up a lot of mains hum.

The simple fix is of course to turn down the volume on those channels, but I wonder if this could be fixed by adding a pull-down resistor to my outputs. It's only a short cable run of a few feet, but with no power my DAC outputs are high impedance / floating and that's enough to cause mains coupling into those lines.

I guess it's more common practice to add pull-down resistors on device inputs, but I don't want to mess with the Mackie.

I'm wondering what's typically done in this situation with pre-amps, DACs and the like. If pull-down resistors are added, it would solve this problem, but could affect the efficacy of the output stage, which would now see a lower output impedance when in use than it otherwise would. And I guess, more importantly, the desk, or other gear I plug the DAC into would see a higher input impedance.

I could:
1. Do nothing, and mitigate the hum by leaving the DAC powered on or only open those channels on my mixing desk when I'm using them.
2. Add a pull-down resistor. In which case, what value suits this application, and would I also add a capacitor in-line so I'm only pulling down A/C?
3. Something else I haven't thought about.

Thanks in advance for any suggestions.

Craig

Can vintage receivers and amplifier sound like new amplifiers? Lets discuss 1974 to 1980 vintage vs new amplifiers. New and vintage are of same design. There is no new technology. Both amplify a signal the same. Both use transistors, capacitors and resistors. Both have an AC to DC power supply. What are the differences? Plenty in the components. What is the difference in components?

First, the rectifiers are very quiet today in the power supply. The power supply is paramount to good sound. All an amplifier is, is a modulated power supply. Most new amps use Hexfred and some may use SIC rectifiers. Old receivers have noisy rectifiers and were not closed matched either adding to the noise. New amplifiers use better filtering vs old amplifiers or receivers.

The old capacitors in the audio coupling circuits (circuits that amlify the music) were of ordinary design and never produced to accurately pass audio. In older tube amps, they were quite good in many cases of passing good audio. Tube capacitors are low value film type capacitors thus better materials were used. Solid-state uses high capacitance electrolytic capacitors and these were not made to pass quality audio. They were the same as a power supply capacitor that has a different function. New amplifiers use what is called audio grade electrolytic capacitors and they greatly outperform the old capacitors.

The transistors are somewhat the same in late 1960s and '70s amplifiers. Old transistors were low noise audio transistors, but low noise at the time period. Newer transistors operate more quiet. But, the level of low noise does not make a large difference in the sound. Phono sections are the largest benefactors of quiet transistors. But, for the most partsnew transistors do not necessary sound better (some may disagree with me). The are exceptions such as First Watt amplifiers. But, you are getting into an area you may need $5K speakers to clearly hear the difference. First Watt has many models and the transistors are tuned for a certain sonic signature. If you can afford a $4K+ amplifier, you may have no interest in a vintage amplifier or receiver.

Resistors have not changed much. Older vintage used for the most part carbon resistors and newer amps use metal film. There are boutique resistors today vs none years ago. They may make a difference, but frankly not a lot. Most new amplifiers use standard metal film, not boutique resistors. In some cases new amplifiers may use carbon film for the more lush sound. Not a bad decision. Old potentiometers may require a DeQxit cleaning. I have always had good success on 'scratchy' pots, but you may need a new replacement. Most 1974-1980 used a separate power switch, thus new manufacture is readily available. If an odd resistance is encountered, replace with next higher resistance pot and bridge the potentiometer with a 1/2 watt resistor to achieve original resistance.

So, what happens to a quality designed vintage receiver or amplifier using the better new components and an upgraded power supply? A lot! First, the small soundstage becomes huge. Better clarity and lower distortion. This includes higher order distortion that also effects the quality of sound. The power supply can use 2 to 2.5 times the original capacitance for better filtering. The new capacitors are much smaller than old capacitors thus fit well in the higher capacitance values.

Old receivers and amplifiers may use an op-amp in the phono section and at times in the pre-amp. These old op-amps were not designed for quality audio like the new op-amps. And, some prefer discrete new design vs any op-amp.

Some think when you upgrade an vintage amplifier or receiver, you will still get the old sound. They also do not think the superior parts adds to the sound quality. These same audiophiles are not technical in the least.

I say you replaced the poor performing parts, what's left? Transistors? Older carbon resistors? The transistors do not make a huge difference. Both old and new are made out of the same silicon. Old carbon resistors are still used today. Basically carbon is carbon, nothing complicated about that!

An upgraded vintage amp and receiver will sound very different and very good. Rebuilders on ebay used audio grade capacitors. They may need to be prompt to double the power supply capacitor capacitance and to use Hexfred or SIC rectifiers, but they will and can upgrade your vintage receiver for a base cost around $400. They will check for out of tolerance resistors too. They also know what resistors to look for due to their experience.

I used to say no way to solid-state as I am a tube amp audiophile. I rebuild an Allied 395 (same as Pioneer SX-1000TW) and was shocked how good this receiver sounded. It is close in performance to my best tube amp and I used Revel M22 speakers that are reported to outperform KEF LS50. Not a shabby speaker to hear quality sound despite what one audiophile said. I have not directly compared my Allied 395 to a new Rega Brio or Cambridge CXA81 amplifier, but I think my Allied 395 would compare. Would my Allied 395 compare to a First Watt amp? No way, but it still sounds good.

Three non op-amp vintage receivers are: any Pioneer in the SX-800 (not SX-890) and higher number such as SX-1010, etc. Any Marantz 22xx series. And, the low cost sleeper? Onkyo TX-2500 MKII (40 watt per channel) & TX-4500 (60 watts per channel).

Your thoughts?

Hi

My first post in this part of the site.

I am just starting to use Spice to model analogue circuits for the audio out from DACs. Several DACs provide their output as a current swing. As an example, the classic TDA1541 sits at a -2mA current sink with no signal and then swings ±2ma for full level.

I know that a current source with both AC and DC characteristics is available in Spice but the actual behaviour of a 1541 o/p is going to be more complex than that e.g. a finite output impedance. I thought about modelling this as a resistor in parallel with the current source?

Also, what is connected to the other end of the current source? My two current thoughts are either ground or the -6V supply.

TIA

Michael

I’m looking at building a new HIFI and at present are in the process of selecting components.

The system will be a DAC with DSP -> AMP -> 2 way speakers bi-amped with active crossover. I have the scope to add a sub later if I feel it’s needed. I also have the gear and understanding to take measurements & implement for active crossover.

Based on my research my current thinking is;
1. DAC - miniSHarc DSP + Buffalo III DAC
2. Speakers – SEAS W18NX001 + T25CF001 (there are a few plans around based on these so I can easily change cabinets if desired).
3. AMP - HYPEX 4 x UcD180HG with HxR


My Questions;

1) HYPEX Modules – The UcD180HG with HxR will be sufficient to power the proposed speakers, but I’m wondering whether it’s worth considering upgrading 2 of the modules to the UcD400HG w/HxR for the W18NX001 drivers for additional headroom (n.b. The W18NX001 is rate at 90W RMS continuous into 8Ohms). Therefore UcD180HG for the highs UcD400HG for mid lows. Is this just overkill?

2) For the tweeter, a potential upgrade would be T29CF002 but is a massive step up in price vs. the T25CF001. I am considering the T29CF001 as a substitute but is still double the cost of the T25CF001. Would it be worth it? What can I expect?

3) Speaker Porting – If I was building a Sub I’d definitely go closed box for the benefits of a flatter response (understanding impact on power requirements). Can the same be done for Mains (i.e. sealed box)? I don’t see a lot of un-ported designs so am wondering if there’s a reason why other than efficiency? I’m thinking of trying say the SEAS Bifrost or Troels CNO-T25 designs but un-ported.

Any thoughts and experience with the above appreciated.

Thanks in advance

I needed a U1899 fet to repair and old instrument. In my search for data I found this data booklet. So here it is, in case it may be of use for others:

http://bitsavers.informatik.uni-stuttgart.de/components/siliconix/_dataBooks/1986_Siliconix_FET_Databook.pdf

It is too large for upload. Should the one at the link disappear I have a copy.

(This part of the diyaudio site seems to "self-oscillate" the most about old parts. One of the admins might move it to a better location - thanks).

I've got this issue with the HF section of one DCX464 being almost 5.5 dB less sensitive at some frequencies than a second unit. I'm hoping anyone has something to say about how this is possible with such costly units. Could it be that the build spread is this big? I very much would like to doubt that!

A bit of background:
I've been working on a synergy horn using the B&C DCX464-16 and Faital Pro 12H500. The horns are finished and pretty well constructed with only minimal differences. But when measuring the two DCX units this afternoon, the HF of one was almost 5.5 dB down compared to the HF of other unit at 3.6 kHz 😕😕.

No settings were changed in between, as can be seen from the mids respons of the two units, which is pretty identical. I have tried covering the woofer entries with solid plywood, but it made no difference.

A thought that came to mind was, maybe they had accidentally put in an 8 Ohm HF membrane instead of a 16 Ohm version, but that would result in similar frequency respons curve, right? Just to be sure, I measured the DC resistance, which turned out to be 8.3 Ohms on both units...

I removed the "faulty" HF unit to check if there might be an issue with the membrane, but it seemed fine.

I'm at a loss here and my next step will be to contact the distributor (toutlehauteparleur in France) to apply for an rma.

I thought maybe Bennett Prescott would have some insights?

I was about to start designing a passive crossover for the horns, but this frequency difference makes it really difficult. What will happen if an HF gets blown and gets replaced? There's no way to design for this big differences in SPL🙁.

Update:
For the solution, see post #13.

I have a B&O ICEpower 200ASC that I was thinking about using for the output of a guitar amplifier.

I also have a 500VA Hammond toroid power transformer 120/240:120/240... I'd wire it 1:1.

Electric guitar bandwidth is only about 80 to 1200Hz-ish.

The purpose would be to maybe "warm up" the sound a bit.

Am I asking for trouble / bad idea?

Hello,


Its an amp form 70s, TEC System 5000 (supposedly Toshiba Electric Corporation.) Pream + power amp.


This morning a high gain condenser mic feedback happened and it got quite loud. The mic signal came through an external audio mixer output inthe the preamp's RCA input.

After the event it seemed the right channel is dead, but then I discovered that it plays just at very low volume compared to the left one. The two power meters also show different power levels.

Not sure if the power amp has any a speaker protection system (ie relay) except a electrolyte capacitor in the center point of NPN and PNP transistor between two 0.33 ohm resistors. Im not wrong about the capacitor.

It seems to me that the power transistors are operational.

Can you suggest what to check next or perhaps you can already assume whats the oroblem.

Thanks
Rando

Just recapped this one and looking through the service sheets the copy I have at least doesn't have the dc balance adjustment procedure or values, does anyone have any experience with this?

Thanks

Hi Folks!
Now I'm developing a new version of "FreeDSP Classic SMD A/B" which is named "FreeDSP Classic SMD A/B plus II"
This board has two additional features. Embedded PCM5102 for DIG6/7 output plus Ez-USB Fx2LP board slot for embedded FreeUSBi .
The other features keep the concept as FreeDSP Classic SMD A/B.

• Dual configuration EEPROMs for program A/B selection.
• 2V r.m.s. Unity Gain I/O
• Power ON/OFF and Reset muting.
• I6S(3 times I2S) buffered digital output Header
• I2S Digital Input
• Single DC12V power supply.

The current version board had PCBA done at JLPCB. Design information will be updated soon.


CyberPit

From Curt's speaker design works page: Speaker Design Works

The latest finalist design seems to be using a Morel CAT328 tweeter rather than the discontinued Dayton RS28F. The older schematic is below:





Does anyone have the updated version, or know the parts values?

TIA!

Hello,

My Pioneer TX-608 tuner has strange manners.
I can keep turning at the ‘tuner’ wheel untill tomorrow, nothing happens.
It seems as he has no reception at all.

The signal indicator doesn’t move, also the fine tuning meter doesn’t move, whatever I do. There is power on the unit.

My radio knowledge is not so fantastic. Last time I was really helped alot by the community here, so I wonder if there’s anyone who can help me find the problem?

Thank you in advance,

Vintagelover

Pioneer TX-608 AM/FM Stereo Tuner Manual | HiFi Engine

I have a valve integrated, audio innovations series 3 MK2. Uses 12AX7 and ECL86.

Lovely amp, great sound etc etc etc. I also have a chinese 6P1 amp, also ovely soudn but different flavour.


Both have a volume control that is a simple pot, 100K I think.

AFAIK, on the chinese amp this volume control is situated on the line in from the input RCAs, ie acts as a simple attenuator. Why is it when I turn the pot up all the way (ie defeated) I get hum/buzz etc etc (like full power)?

Next question, the AI300 is the same although I think that in this case the volume pot is after the preamp section and before the ECL86s. Turn it up more than halfway and you hear a significant amount of hum/buzz. Again, why is this?

I was under the impression that with the pot turned all the way up, you were basically having the amp running at full power (eg like a power amp). Reason I ask is that I've just built a passive pre and was going to use the attenuator on it to control volume rather than the one on the amp. (although even with the volume halfway up on either amp, befoer I hear buzz, I still have enough gain). A RLD should be started in the near future.

A bit rambling I know, but comments please!

Fran

Thanks in advance for reading

What started as a faint hum in the left site of my 2CH Marantz amp has inspired me to rebuild the whole thing on perf board.


(The gold/black theme was completely by accident. Had no idea the protoboard had gold contacts on top.)

Sadly a 2SC3423 transistor has transitioned into the afterlife, and I think the upstream 2SC2705 has terminal cancer (hFE is 74). I do not wish to spend $40 getting two exact replacements to Canada and find out that they're fakes.

(enlarge)

One question I have is whether Q721 sees more than 40V? The A1015/C1815 would be a good candidate but Vce-max is only 50V.

I have on hand:

New from Digikey:
10x sets: BC557B/BC447B https://www.onsemi.com/pdf/datasheet/bc556bta-d.pdf
2x sets: KSA1381E/2SC3503D https://www.onsemi.com/pdf/datasheet/ksa1381-d.pdf https://www.onsemi.com/pdf/datasheet/ksc3503-d.pdf
4x sets: KSA1015Y/KSC1815Y https://www.onsemi.cn/PowerSolutions/document/KSA1015-D.pdf https://rocelec.widen.net/view/pdf/riwfxedwmh/ONSM-S-A0003585266-1.pdf

Also authentic Sony pulls: 1x set 2SC3421Y (hFE 153)/2SA1358 and 5x sets 2SC1815 (hFE 241)/988a

Can you please recommend replacements for Q721 and Q725 based on what I have?

A) Replace left-side C2705 (Q721) in section E with right-side C3423 from section F (hFE 188). Replace all of section F with A1381/C3503 sets?
B) Use BC557B/BC447B (voltage?) for both sections E and F (because noise doesn't matter in the driver stage?)?
C) Replace all of section E with KSA1015Y/KSC1815Y (voltage?) sets and all of section F with KSA1381E/2SC3503D?
D) Replace all of section E with section F plus the one C3421Y, and all of section F with A1381/C3503 sets
E) Other?

I'm looking for the service manual or the wiring diagram of a "Teac model 2" mixer ..... not 2A, can someone provide it to me? thank you

Hi,
I'm looking for specific resistors, inductors, and capacitors for a speaker build.

I'm willing to buy larger no specific lots if they include what I need and do not cost more than my solen costs.

I'm looking for high quality audio grade components.

Capacitors
300uF - Pair (or 6-100uF or 4-150uF)
33uF

Inductors
0.1mH - 18 gauge min
1.0mH - 18 gauge min
3.9 or 4.0mH - 16 gauge min
18 or 20mH - 16 gauge min

Resistors
2 - 7 ohms
4 - 7.5 ohms

I have the following set of conditions. My source is a 2 channel DAC board. The output from both channels should be an identical mono signal. I need to feed the inputs to an ICEPOWER 50 ASX2 (BTL Mode from the company). It has two inputs and one output. As I don't have a scope, I don't know whether the signal is inverted on the output of either DAC. It appears that the output is floated above ground as the ground side of the output measure 33.5 ohms to ground on each channel and 67 ohms across both black leads, one from each channel.

I purchased the GhentAudio chassis which is not different than the pictures shown on their web site and I could only find one orientation that would provide 4 screw holes properly aligned with the board. It is more centered than the arrangement shown on the web site and leaves no place to add an RX board if one is needed. There is no schematic or drawing showing how to wire the inputs using the XLR, RCA and switch to select XLR or RCA, so I am not certain how it should be wired up. I am including the information I have on the DAC board output and a photo of the schematic & block diagram shown.

As I understand it, the AMP needs to have one input inverted. Can I just switch one of the ouput leads from the DAC? Will I need to use an RX card and if so, where and how do I mount it? See the actual board mounted in the chassis.

Thank you all in advance for any help you can provide.

I really hope I'm posting in the right place, there doesn't seem to be a subforum dedicated to stupid questions. I'm having a hard time trying to pin down which speakers I should chose to build.

I'd like to build my own multi-way speaker system instead of sinking a lot of money on ready-made speakers. I've been scouring the Multi-Way speaker section, looking at pictures of members system, but it actually gotten me even more confused as to which setup I should choose.

I've been using KRK Rokit's 5 active speakers for years. They do the trick nicely, but now, it's financially viable for me to upgrade to passive speakers and an amp system.

I took a look at commonly available speaker kits, such as Paul Carmody's, but I'd like something a little weirder, a little bigger, and perhaps a little better. What I'd like to end up with are a pair of big floorstanders, something in the ballpark of Troels Gravesen's 3-way floorstanders or 5-way speakers.

The speakers would be used in my 20sqm bedroom. I'm not pressed for time and would like to build them slowly over time. It would be nice if I could keep the budget sub-700$.

I'm looking for any pointers, any suggestions. I'm sorry if my questions seem redundant or uninformed. I guess we all have to start somewhere.

EDIT: If that's of any help at all, the speakers would be placed in two corners of the room. The room itself is a fairly standard rectangle, but as a high ceiling, about 3 to 3.5meters.
I have access to a fully fledged wood workshop, but I don't feel like getting into a very complex build.

Looking for a refined switch to toggle between two inputs for a DAC.


Thanks in advance for your suggestions.

To connect a network player. The VD player I had in mind was an old pcm1795 based Luxman

I have built, bought, exchanged and accumulated lots of stuff during the time and I have to let some things go.

For sale this Alpeh 5 power amp built to the best of the specs and components:
Dale military 1% resistors.
Nichikon Fine Gold caps for signal
Toroidy 600VA audio grade toroid
120000uf per rail united chemicon black capacitors bank.
Jantzen audio silver cables for output signal.
Big, heavy and nice case with and oversized radiators.

It has less than 60h of running time.
I could let it go for 1400€ shipping to EU included.
Just the case is more than half of the price i'm asking

hi, i am looking to purchase a pair of
12bh7 tubes

black plates
brimar or mullard or RCA
measured with proven results
preferably from EU

Hello.
I would need some help from Denmark. there is something I'd like to buy at Eskilstrup but the seller doesn't want to ship to Spain.
Thank you in advance.

Hello!

Working on a SoundLab CD player (part of a Coomber 2241). There's one piece of the circuit board which I cannot identified, only marking on it is "8643", and it's marked X1 on the circuit board. Fuse?

Any comments one this 2 way high end speaker kit from Seas?

18cm Nextel coated paper cone woofer and a very expensive new 29mm tweeter.
http://www.mamut.net/dynabel/the_bifrost.pdf
They have chosen a EBS alignment - what does that
mean?

Hi

I'm going to be winding my own inductors for my speaker build.

I'm trying to figure out the best dimensions in terms of the length of the coil and the internal diameter.

Looking at Solen Inductors (which is what Caps I'm using), they seem to stick to 1:2 length:diameter eg 25mm length and 50mm diameter.

Jantzen seem all over the place as do most others.

Then I found this article: An introduction to the air cored coil
which suggests trying to make the cross section of the windings as square as possible. This seems to back Solen's measurements.

The best example of a Solen inductor is 1mH which is 16x32x64 lxdxD.

Does anyone have any other info to help?

In the article in the link above, it suggests a circular cross-section would be the best but they are difficult to manufacture. Considering I'm doing everything from scratch, I'm sure I could get close if not a rounded-edged cross section.

Cheers

Hi all

I am just starting to use Spice to model analogue circuits for the audio out from DACs. Several DACs provide their output as a current swing. As an example, the classic TDA1541 sits at a -2mA current sink with no signal and then swings ±2ma for full level.

I know that a current source with both AC and DC characteristics is available in Spice but the actual behaviour of a 1541 o/p is going to be more complex than that e.g. a finite output impedance. I thought about modelling this as a resistor in parallel with the current source?

Also, what is connected to the other end of the current source? My two current thoughts are either ground or the -6V supply.

TIA

Michael

Good day I'm having trouble identifying the value of a zener diode #c125t it came out of a theloudest.com tL1023 class D amplifier in the audio section that's near the drivers on the side connected to the negative rail.
I've googled it the number is recognized but there's no information about it. I'm lost can anyone help, please.
This amp needs to get of my bench

Hi All,

I have for sale a pair of 18 Sound NSD1095n 16 Ohm 1" compression drivers.
Very nice,detailed sound. I've owned Beyma TPL150 and these are up there on that level when mounted on XT1086!

Looking for £200 inc. UK delivery. Will ship elsewhere at cost.

Thanks for looking!

Hi, I have for sale two pairs of Wavecore SW259WA02 8ohm, aluminium cone 10 inch subwoofer drivers. Much underestimated drivers! Can get nice and low in a small box.
All light use and working 100%

£360 per pair inc. UK shipping.

Will ship worldwide at cost.

Specs here: SW259WA01_02_subwoofers

Thanks for looking!

I never thought sitting eating my breakfast today that I would encounter a pianist that would effect me so profoundly - Mine Kawakami.

Checking her out online I found that much of her music is only available for downloading but then I got lucky and found - CD Japan.

Can any Japanese members direct me to a Japanese site dealing in s/hand CDs. There's nothing showing on sites outside of Japan. I'd like to buy quite a few of her CDs, so mint second hand would save me a lot of money - appreciate any help.

Stuart

Greetings Maestros,

here i am building amp based on iraudamp9 with 3 pairs of output, with the intention of driving IRFB4227 OR IRFP240. old project that i failed to run before but now i seem to know part of the problem, much thanks to Jan Lester for his advice on this amp. it would not be possible without him.
here is the spec:
similar to IRAUDAMP9 notes with some extras, and i play around with its OCSET and CSH
in the hope of not tripping.
on CSH pin: 7k6 to diode and 2k2 to Vs
on OCSET PIN: 3k3 to vref and 7k6 to -supply
on DT: tied to -supply through 2k2
on Vb: bootstrap cap 47u to Vs
on VCC: reserve cap 47u to -supply

currently its driving 3pairs of IRFB4227, it was heavy to drive, so i took external switching supply to supply the mosfets bias, then it stops glitching whenever i try to crank up the freq. seems like the bias current isnt enough as Jan has mentioned. (because my LM regulator is floating in the air without heatsink, i didnt notice it was overheating).
now i could achieve 360khz (maximum trimpot turn: because my trimpot is only 500ohm), but then the
IC gets to almost about 60 degree celcius
while the totem-pole 2n5551/2n5401 gets to almost 70 degree celcius.
again, upon consulting with Jan, it seems that 2n5551/2n5401 is not suitable for the drivers, in term of wattage and that it needs to have low saturation voltages. if anybody could elaborate on whats happening here, i would be glad.
i think IRS2092 has a hard time driving this totem-pole load. (again this is what i feel, if anybody has experience and knowledge on this, feel free to let me know), or perhaps there are other factors causing this irs2092 IC and totem-pole driver to get this hot,
my target is to achieve no more than 50 degree Celsius on both IC and totem-pole driver hopefully.
and hopefully it this could crank up 1k7watt with 90volt 2 ohm without tripping or overheating anything. Amen.

Hi all
after many years of work, my 6950 starts to show some issues when turned on.
The volume control starts showing random values rather than the one that was left before being switched off the day before.
Moving back the volume there is a "error -2" message (indicating a mismatch beteween the volume and the value indicated on the display).
Switching off-on again everything goes fine.
When the working temperature is around 40° (display indication) everything goes fine.
As I hear a relè with a bad noise during the seconds before the "error -2" message, l suspect that maybe the reason.
Does anyone have a schematic to help?
My version is the full solid state 6950, not the hybrid.
Thanks in advance for your help.

Hi!
I am in the process of building my first project. I plan to post it here later, as there will be some result. It's a long story.
Almost all components have already been purchased.
But I again had the idea of MTM, although I had already abandoned this idea, as I thought that in the active version, MTM has fewer advantages + a limited budget.

My drivers set: 12" + 4.5" + ribbon tweeter
Makes sense MTM: 12" + 4.5" + Ribbon Tweeter + 4.5 "(as close as possible)?

4.5" from 250-300 Hz to 2500-3000, Tweeter can from 2500 Hz without distortion

Will a large effective area Sd be more useful than negative from interference?

Thank you

Amp will not power up .

It came in with blown power supply fets gate resistors and drivers

Replaced those parts . Now the amp will not power up .

I get 0:00 volts on all pins of the 3525


Any ideas ?

I replace a 4 zone amp with a new 6zone x 60w amp for my local golf club, the existing speakers are 100v line and it worked great. I added a new zone with 3 new 100v line speakers I bought (1.5/2.5/5/10/15 tapping) no matter what wattage I select as soon as I connect them I get this pulsating squeal sound. New to this so not sure what is happening. Ran a temporary cable to an open area to test them without any possible interference and they did the same thing. Not sure how to resolve. Any help?

It's labeled United Electron with a 5-21 code on the side. I know they relabeled tubes from everywhere for re-sale. Bottom shows a circle with 13 in it.
Thanks

Goodday all.
I need some advice plse. I'm working on a Pioneer SX990, but the wiring is a bit confusing on the output stage board. Why do they use two different earth points on the board for each channel.E1 and E2 and E3 and E4 seems to be the same earth point. But if you look on the output board schematic ground 1and3 and also 2 and 4 is split. Can I not just connect ground 1 and 3 together and 2 and 4. This is a bit confusing.
Regards
Jan

If Russian write 68000 Mk, is it 68 uF?

Thank you

Hi all,


I'm looking for a volume control potentiometer (dual gang, 100kOhm, logarithmic) that has a threaded length > 10mm. I had a look on Mouser and all I can find is some push latching ones that I'm not sure I want.


My front panel is 8mm thick aluminium, and I need to be able to have some length to the threaded section of the potentiometer so that I can screw on the mounting nut + washer.


I don't have a bench press, so can't recess the mounting hole easily at all, and there's not enough space in the box to come up with some other mounting solution.


Any parts that might help please?

Hello everybody! I am attempting my first repair on the plate amplifier from a QSC HPR 153F 3-way pa speaker.

I recently bought it used and had it freighted to me. It definitely sat in the cold for a little while. When I first powered it on, I noticed very little bass compared to the other HPR 153F I already had. A few seconds later it made a loud honking sound and flipped it's internal breaker.

Taking a look inside revealed a few shorted transistors (2SC5200/2SA1943)
I also noticed all of the 0.1R 2W resistors were measuring around 0.4R.
The pcb has a "hot" side with all through hole parts. I think I'm going to just replace all of the parts on this side. I've also noticed a couple open circuit resistors on the smt side I will need to replace.

Should I be considering replacing the electrolytic capacitors as well?
Cosmetically they look fine.

Also, should I check the resistors in the other speaker I have? Could this have been the cause of the failure of the amplifier?

Thank you!

EDIT: I learned from a friend to check the internal resistance of the meter before measuring something so small. Most of the resistors were actually fine.

The system consists of:

Faital Pro 15 inch, using MiniDSP LR2 xover

Mid bass 8 inch, using MiniDSP LR2 for High Pass only

Mid bass 8 inch to horn, passive LR2

Horn to tweeter, passive LR2.

Do I follow the "textbook" rule of + - + - in this four way?

Regards.

Hi guys i decited to create this thread tho take some information about 4'inch, recomendation, advices, best bang for the buck

My personal project is using a MC/145 PHILIPS box, and My plans are to replace the original driver with something more modern, around 15 dollars per speaker

I am completely inexperienced in building cross overs.
I have a need to build speakers.

What resources are best to learn the components and foundational design of passive cross overs?

Books, videos any help?

Thanks,

Joe

Way back in pre-history, I built the Dynaco Trio -- Preamp, power amp, and tuner. I still have them!

Having the utmost respect for Nelson Pass, and his design genius, I made my way here. I thought I'd start with the WHAMMY so I can jump right in with my Audio Technica ATH W-1000 Sovereign cans. I'm sort of leaning towards waiting for the chassis to be included with the parts kit -- assuming it's not another year before that happens!

If the build goes smoothly, I'll move into the ACP+ and then build a pair of ACA V-1.8's to drive my Omega Super 3 XRS towers. I'll probably be ordering a pair of Zu Dirty Weekends at some point this year.

This site is awesome! Friendly, knowledgeable members, and access to the best designs (and mods) on the planet!

Hello,

I've been lurking here for a while, and have been intrigued by the positive feedback for 15" Audio Nirvana drivers. It seems, though, that current production is essentially a new speaker (apparently made in a new factory since some time in 2020). I've attached datasheets for the old and new variants but for a quick glance:


.. and those frequency response plots! It looks like the old version is about 92dB@30Hz, 96dB@40Hz where the old one is about 83dB@30Hz, 85db@40Hz; significantly less output at low frequencies. In fact, the new variant looks like it starts rolling off at about by 6dB/octave 100 Hz.

The vendor mentioned that this is the best sounding driver of all they manufacturer, that it represents an improvement over the old Super 15 ferrite, and that specs are really meanigless. Even if I were to accept that at face value, it does appear to me that this is a totally different driver, and any advice/recommendations/praise from prior to 2020 doesn't necessarily apply to the current offering.

So, would folks agree with my assessment that the current Super 15 is essentially a different product than the old Super 15? If so, does anybody have any experience with the new variant?

Thanks!

I have the newer 1ohm Stable versions of the CXA line amplifiers. This the Monoblock 46cxa8001. Powers up green Led, No audio present at speaker terminal. Measured 1.47vdc across speaker terminals. It been awhile since I've repaired these, need some help to rimind me of the trouble shooting steps.

I have hesitated about posting this because I assume it is not a new idea, and it is only justified by my subjective opinion of the effect.

I originally used this as a way of hiding exposed edges of self builds, and noticed an aural effect, that I could not ignore. I now would not have a speaker without these additions, so convinced am I of the benefit.

As the picture shows I have a strip of thin wood (or card) <3mm thick about 3-4 cm wide the length of the cabinet on both sides. It stands away from the baffle about 1-2 cm.

The effect it has is to bring a more focused sound, to the extent of increasing presence, and improves the high frequencies.

It takes 10 minutes to try it out fixing the strips with blutak.

My uneducated guess is that the strips interfere with the diffracted waves from the edges of the cabinet. I would be interested in any views.

Hey there,
New to the forum. Id like to try my hand at speaker building. After doing some looking around, I've become intrigued by the idea of a single driver full range speaker. To be honest it sounds almost to good to be true. So I assume Im missing something here. Could I get some of the strengths and weaknesses of this type of speaker design.

From what I understand there is no crossover required for this type of speaker, and the bass comes from the enclosure design.

I wonder why I haven't seen more commercial versions of this type of speaker. If this is in fact a very nice sounding design, I think it'd be good first speaker build for me.

Thanks Justin.