Hi Thanks for reading Is it okay to use safety capacitors ceramic x y type, in an amp power supply, in place of small film or aluminium electrolytic.
How do you think this may affect the psu
Also, i'm getting some dc on the mains which is causing my toroid to buzz, are there any transformer types that are not so affected by dc mains ofset

Hello I`m having some trouble to find a way to bypass the PD0050, so ideas for NON OS or lowering the Oversampling rate will be welcomed !
If i do use the data input LRC - DATA and BCLK the input format should be ? Any schematic will be quite handy ! Thanks !

Selling my Audio Note Lexus LX-96 Speaker cables.
The cables are different in size - 1 pair is 3 meters and the second is 2 meters. They were made specifically for me by the owner of Audiofilo in Valencia Spain - an official Audio Note reseller. Cables made in December 2021 so pretty much burnt in and are in perfect condition. Sale due to upgrade.






Sale price is 475 euros. Shipping to EU. I will also throw in spare silver jumpers I have in stock.

It is somewhat ironic that the owner of a brand new USB turntable with 6g tracking force is thinking of contactless playback, a playback system that will preserve records forever, however I hope you will forgive me for starting this discussion. It has been in my mind for several days, inspired by this picture of record needle and groove playback.

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Hello,

I receive my new pair of Bliesma M74B recently and would like to share some results.

While expensive I find that newcomer is a breakthrough in large dome medium driver for a long time. Hificompass did extensive measurements on those and all have been confirmed here also.

What I would like to share is the use of a passive twin filters (only two inductors and two capacitors to reduce somewhat the two main breakouts (around 13-17 kHz) of the beryllium dome.
You will notice that the two peaks are reduced by about 10 dB but more important is the reduced third and fifth distortion figures.

Of course at those frequencies, it is mandatory to measure exact values of the capacitors and adjust the inductance accordingly. I use 20 x 16 x 30 m coils that I found at a very low price on internet and 1 mm diameter enameled copper. I also use a RLC bridge to get values that were optimized via the wonderful VituixCAD software

The accidentally erased master tape of Steely Dan's 'The Second Arrangement' has resurfaced in the form of a well-preserved cassette and DAT tape. Steely Dan fans worldwide are in ecstasy after it's discovering:
https://www.theguardian.com/music/2...ow-steely-dan-fans-uncovered-their-holy-grail
The complete story and song can be read and listened to here:
https://expandingdan.substack.com/p...an-roger-nichols-tape#§the-digital-audio-tape
Also, the tapes will go on auction to cover the costs of the studio work to get it digitized.
Enjoy..

The maximum output power (clipping) is 14W (when the screen consumption of FU50 is 37W), the damping coefficient is around 4-5 (although I think damping is not important, this is another topic), the distortion of 5W is about 0.5%, and the distortion of 10W is about 1.8%The red font on the circuit represents the working points measured in practice. So this circuit has these characteristics:-Maximize the scope for selection and management to reduce opportunities for JS to hype specific models-Open loop circuit, more friendly to output transformer-More combinations and combinations for easy gallbladder replacement fun-Minimize the use of transistors as much as possible, facilitate construction, and be friendly to beginners. Because in fact, both stacked and unordered can be partially replaced with JFET or MOS transistors. However, there are not many opportunities to purchase genuine products domestically, and MOS is even less friendly to beginners in welding and installation. Nevertheless, it is still unavoidable to use MOS transistors for voltage reduction in the grid grid power supply.-Try to use impedance compatible output transformers for easy modification of old machines.-Try to use self-sufficient bias to facilitate direct replacement of power tubes. Still, I do not object to the modification. If possible, you can change it to a fixed bias for self-sufficiency, but please also modify the power supply voltage together.-Regarding C3, it also affects low-frequency transients and frequency responses, and if possible, you can try it yourself. The implementation uses a 4.7uF capacitor.-Regarding the feedback quantity, R14=470K is a moderate feedback quantity. If a resistance value between 330K and 430K is used, there will be more changes and distortion will be reduced. Let's try it out for yourself.

Hi, I am running two of these modules at +-60v and the bias current from cold is 60mA per rail is this too high?

Hi guys,
I was wondering if any might have a schematic for an old Fosgate PR250 amplifier (70s vintage)? I recently picked up a couple of them, as I recall they sounded great and had a novel amplifier circuit. They did break a lot though. I'll probably replace the amp portion with a chip-amp.
thanks,
Leo Smith

I wanted to bypass the horrible ESS DAC in my Oppo BDP105 to play through my tried and true RME DAC.

Are there any plug and play solutions to do this?

Do these look okay? They are not very deep, 3 1/2" x 16" x 24" to be exact.

I will load with a rockwool after I fix up the 1/4" back panels.

Being somewhat shallow as they are, will they be very effective with heavy rock wool behind stand mounts?

Next I am planning to make at least one larger diffuser framed the same way, also loaded with RW. Something other than skyline. 24" x 48" x D? If I were to style it the same way as the three imaged, only fashion slats in an every other pattern across the front. Questions are how wide and how widely spread apart should they be to turn that absorber into a panel that does some of both for MF & HF?

Similar idea to certain dual purpose acoustic panels popular on the open market atm, the multi frequency square shapes.

I'd like to know the impedances of these drivers: HT, MT, and TT.

Can we trace back the impedances of the drivers from the crossover schematic?

Thanks for the help.

Hi all, I have built a Pi-based 3-way active crossover using CamillaDSP. However I do not currently have a manual volume control, and this is next on my list of improvements as it's not all that convenient to do it via CamillaGUI every time. I am wondering if anybody can recommend a nice-looking volume knob (black) that they've used on their own project? I did find some candidates on AliExpress but they tend to be more focussed on "value" and I want a more premium look.

I have 6 of these ICs (genuine NOS).
2 sold in second, now only 4 pcs left.

$50 each + shipping,
or buy min 2 pcs
then shipping is free

PM me if interested

Thanks

Hi
I was watching this video.
Login to view embedded media He is using a 15 watt chip amp and he uses 0.22 Ohms 2 watt resistors
to combine 2 channels into one 30 watt channel .
His speaker is 8 ohms.
I have a similar situation I am repairing a guitar amp but I have
A 4 ohm speaker...
What resistors should I be using?

Thanks

Does anyone know where to get a schematic diagrams for a Crown 400 amplifier?

I have three of these woofers in as new condition. $125 a piece, you pay shipping. Each box is about 9lbs, shipped from 47150

Hi everyone, I've been on a speaker building hiatus for a few years but getting back into it

For this new design I'm working on I want to focus on both something that I screwed in the past and something that I really need this time, which is as flat as possible off axis response

I've been searching for drivers for a while now, tweeters, full ranges and BMRs

Something that caught my attention is that most if not all Dayton Audio tweeters have really good off axis response on the datasheet, almost too good to be true

For example comparing the two bellow, the Peerless one becomes a mess off axis after ~12 kHz and at that level it's 10 dB down at 60° compared to on axis, while the Dayton Audio one it's smooth and not even down comparing 60° to on axis

This pattern repeats for many models and this message would never end if I compared every single one I've looked so far, but Dayton always has a response that looks too good to be true and other brands with a not so good response but that looks more realistic, specially off axis

Is Dayton screwing the measurements? (or purpose or not), is the 1/12 smoothing hiding the mess? Doesn't look like since it would still go down on average

Thanks for any insight

https://www.parts-express.com/Dayto...Silk-Dome-Shielded-Tweeter-275-075?quantity=1



https://www.parts-express.com/Peerless-DX25TG59-04-1-Fabric-Dome-Tweeter-264-1020?quantity=1

hello,

sennheiser offer color rings : Red, Orange, Yellow, Green, Blue, Purple, Brown, Black.

How do you sort colors ?

Same question can be applied to neutrick rings 😉

I recently found

U-PRO2S digital power amplifier module extended capacitor+P2601 balanced io input board module on AliExpress.​

Anyone build with AliExpress sourced parts? Are they legit or counterfeit you think?

I'd post a link but not sure if it's ok. One can search with the above and find it.

Paul

Hey everyone,

I purchased some 6ak5 tubes to start messing around with.

After trying several schematics and nothing working, I attempted my own configuration and this is what I got.

This so far does exactly what I want, except for a high pitch squeeling noise I cannot get rid of. This is pretty much the first schematic that has gotten my a volume output from a tube.

I am plugging this device directly into a 100w solid state amplifier. Again I can hear everything perfectly like the way I want, I just need to get rid of this noise. I attached a schematic.

I was recently pulled over by officer Cal for ‘quoting without attribution’ and have no issue with that but I had tried the partial quote (responding to the prior post) and it didn‘t relay to the reply box, clicked, double clicked, tried a few different things and can’t get it to show up……..am I missing a step?
Using Ipad 5th gen if that matters

thanks, Bob

Help please. We have a PA speaker system we use for events in work but it is only as portable as the length of the extension cable! How can I use this in the middle of a field? Can I buy a portable power supply and if so what wattage conversion would I need for say 800 watts speaker system. Or would I need a power invertor to a leisure battery? Again what size?

Just bought a pair off Ebay for desktop use, but did not realize I need to fill all the way up to 300Hz. Any help appreciated designing a single driver solution for 300Hz and under. Trying to keep cost low on the driver. Thx!

I have for sale a pair of Saburo loudspeakers I built as a test in MDF cabinets. The cabinets would need acoustic treatment (I used the acoustic foam elsewhere) and finishing unless they were used in a garage system or similar. Loaded with treated Fostex FE126E drivers. Drivers will not be sold separately. Pickup only in Oakville Ontario. Asking $150 OBO, lowballers will be ignored.

I came across a speaker manufacturer called Grandale Audio ( https://www.grandaleaudio.com/ )
they seems to have one flagship full range driver of around 3-4" which they have used it in all their speakers.
its available on amazon
https://www.amazon.in/Grandale-17E-Full-Range-Woofer/dp/B09QKQRC9F

this driver has Fs at 110hz and been used in line array model G7 ( https://www.grandaleaudio.com/grandale-g-7/ )

now I plan to use these drivers in a floor stander but not as line array. Instead I plan to use 8 of them as woofers in a sealed or ported box to handle below 300hz. two of them as mids to handle from 300-3khz. then use two drivers as tweeters. one in the front at ear level and one at top as ambience tweeter.

will such a configuration work? I am guessing this configuration is called 2.5 way??

since all are same drivers I shall go with single order filter network.

I need to replace the passive radiators on an old set of Kenwood LSC-6000's. The foam surrounds on the passives is rotted away. Strangely enough, the drivers are okay. The client would like to keep the sound as close as possible to the original, so I'm on the hunt now for a replacement.

Pertinent info:

Cabinet measures: 12" x 24" x 10.25"
Radiator measures: 212mm across TOTAL.

what else do I need to know? The radiator fits down into a recess, meaning that the 212mm would be nice to hit spot on... although I feel that won't happen.

One magnificent piece of equipment! Comes without cart.

Morning y'all.

Have aforementioned machine. Bought it because a previous owner had tried to replace dac chip with a piggyback 2x TDA1541A double crown - paid less than what you would pay for a single double crown. I was chip harvesting but now want to get this unit working because it is so nice. I'd read that they were heavy, but hadn't grasped what that meant in reality - yep, it's heavy!!

There has been a bunch of work done on this be previous so I have contend with all of that in order to find faults. I cannot easily return it to original baseline as a start point. It has been put in NOS, the SAA chip has been removed and was not supplied. As manufactured this unit used the non-A TDA1541 chip but it came to me after attempt to use 1541A chips. I don't have and non-A chips myself so will continue with the bodge. I have to check to see if additional timing cap was added for oscillator.

My first question is relatively simple

I'm pretty sure that the CDM1 should spin up when the cd door shuts regardless of there being a disc present or not?

Currently it does NOT spin up when no disc present - but it does when you insert a disc. It does not read TOC

I've mucked about with these Philips and Marantz TDA1541 players a bit so I'm not a complete novice but I'm also far from being expert repair tech.

The first thing I did was to replace the usual suspect 33u axial cap on the laser control board - this has been my simple remedy in the past - but alas this machine requires something more. Today I will go through and reflow solder, griplets etc. and follow any other suggests I can find online.

Hello everyone,
I'm belgian and my hobbies are HiFi music and old receivers from the 70's. I've just started to service an old marantz cd-73 because 2 technicians didn't want to take a look in it. But I understand why now... I've decided to register on diyAudio cause I want to exchange with other people about my hobbies.

Hello
I have a pair of KEF 103/4 speakers. Did these speakers have an intact front grile cloth? I don't remember if they also were attached by circular magnets? How do I remove the bottom plastic wrap around with the KEF badge? Does it just snap off? I want to replace the U-shaped plastic wrap around with the original black grille cloth under the KEF bage on the right corner? Need help please.
Antohny

I have 12 pcs of these..NOS condition !
=> All gone !

$10 each + shipping (min buy 4 pcs)
or take them all then shipping is free

PM me if interested

Thanks

Up for sale is an used NAGAOKA MP-200 cartridge it has been used maybe 10-20 hours only! So condition is
great!

Item is located in Slovenia EU.
Shipping worldwide.

Price is 300 EUR including shipping.

Payment via paypal or SEPA bank transfer.

I am refurbishing a Teac reel to reel and am replacing a 9 pin male connector that plugs into a noval tube socket on the PCB. I did some searching and couldn't find anything.

Anyone here know where I can get one?

This amp uses NTP35N15 for the outputs .

They are obsolete .

Does anyone know of a good replacement for these ?

I was wondering if it's safe to run a pair of Alpine ddt-s30 tweeters on a Taramps TS 400x4...one tweeter per channel??

Hey!

I'm trying to figure what kind of connectors I need to purchase for the signal section of this AIYIMA board:

https://www.aiyima.com/products/amplifier-board-aiyima-b2d2205-tpa3255-4ch-315w-power-amplifier




Can anyone help? From what I gather it seems like some sort of "JST XH" connector? But no idea which size...

Hi all.

My 2-way speaker project has come to the point whrere i have bought drivers, tested them and know about size of the speaker.
(SBacoustic tw29txn-b & AT 18h52)

I will be using wavequide (jantzen 165mm) on tw29txn-b tweeter, and little selfmade wavequide on 18h52 (diy 200mm)

Thing is i would rather make from aesthetical reasons a sharp edged box, but i know that in "normal" nonwavequide elements rounding edges is benetifical.
I read that 1 inch is minium for it to have positive effect, and even more 1,75 inch is better (more depth in soundstage, reference from Lynn Olson)
----------------------------------------------------------------------------------------------------------------------------------------------------------------------

-So what is your experience? Do i need rounded edges with wavequides or not?
I feel that because wavequides shape sound direction edgerounding would be not needed, but i don't really know..

Hello all, sorry for this question. But I’m not sure if I think correct.

I want to build a +/- 15v supply with only positive regulators (7815).
i have 2 windings on my transformer.
is this how to do it?

R1-R4 is 0.33R
BR// Daniel

Hi All

Looking for a pair of these to try for preamp output coupling duties. Maybe a quad.

250V preferred as I believe these were tighter tolerance (+/- 5%).

I can see there are quite a lot for sale on eBay but who knows which of these might be genuine.

Anything out there?

Thanks

Ian

My uncle has the original RockOla jukebox that came from my grandfather's old pharmacy/sundries store back in the late 50' or so. He's in the process of restoring the tube amp and such, but would like to keep the original speaker in it and it needs a recone. It has a Jenson 12" A12PM in it. He said he found somewhere in Florida, but he's afraid the cost of shipping will be more than the service. He thought he might be able to do the recone himself, but his hands aren't' steady as they used to be at 75 years old and he's afraid he won't be able to solder the voicecoil leads back on without puncturing the cone. So I figured I'd ask the experts here where is a good service that won't mess up this piece of his childhood history? He lives near Branson, MO FWIW.

I'm selling my Beolab 6000 with C Transformer (pair) 100$

Hi folks,

not having found an affordable DSP alternative which is functionally comparable to my failing DEQX PDC2.6p, I am on the verge of deciding for a miniDSP Flex Eight because I'm driving digital 3/4way active DIY Speakers.

Drawback is that the Flex Eight does not have an ADC, so playing my LP records is a significant issue. To mend this I have just found this "Analog Digital Converter PCM1804 RCA to SPDIF 24bit" board at Audiophonics.fr, but am unable to judge if this board would be appropriate for decent Phono AD conversion.

SPDIF or Toslink Output are OK (as an initial solution) as my digital sources are selected with a digital source selection box (CAS2.V3SE) anyway. Putting the ADC board into a box and provide a good, stable and low noise power are no problems, but I think the optimum would be a board integration into the DSP system by I²S connection (maybe as a second step solution).

As the PCM1804 is really an old chip, I am unsure if the 40€ ADC board linked above would really be a viable solution. for Phono

I'm greateful for any advice or pointings to better alternatives.

Thanks and regards,
Winfried

Hello ,
I need suggestions from here , currently I using 3way seal speaker ,off course not happy with low frequency.
So , I decided to add 15in woofer for my 3way seal speaker. In case which one is right choice for my existing system?
For seal AE 15 TDH or AE dipole 2x15in per side .
For future I would like to add full range driver and can be used at two ways speaker too that is why I consider to use open baffle .

I'm looking for a complete replacement power supply either used and working or new if available and anyone can help?Im based in the UK.

Amplitrex AT1000
Testing EF37A

every morning my amp is working and after a few drives lets say 2-3 shutting the car and turning it back on the amp kicks into protection mode. its the second day since installed. i have checked it before on a pc psu and a random aftermarket headunit i had and computer speakers and it worked, i decided to put it on my car and route full car amp kit and it worked. my brother just took it off his car.. its cooling down and even a few hours still cant get it on. i have tried removing all speakers and checked still nothing. also all rcas out still the same. its like the wires are brand new the speakers ohms match with it and rms is good for that amp i dont get why its happening..
well its kicking into protect when i am on acces and starting car dosnt make a diffrence.
and it does not say which type of protect mode i just read online that if the power light is flashing its protection mode and if its solid its working ok.
this is the same as my amp and same wires are connected but hes problem is basic rather than mine
video example Login to view embedded media

This is a reference video on Plywood VS MDF for speaker enclosures.....In a hurry, go to 25:00 minutes in and at 28:00 he says MDF is half as stiff as standard construction grade plywood.....Who knew! https://www.youtube.com/watch?v=EEh01PX-q9I

Hi there,

I’ve done a fair amount of searching and watching YouTube tutorials etc and although I think understand what impedance basically is from the standpoint of a dynamic loudspeaker (driver) and acoustic impedance (air), I’ve found nothing really explaining how they interact. Though I understand it is complicated.

Most information simply tells you how to read the impedance plots/simulations, with very little on the practical uses/implications of it.

I’m interested in bass horns and quarterwave resonators particularly. I’ve heard Tom Danley talking about ‘impedance transformation’ and I think this is what I’m interested in specifically.

Thanks

I have two previously unused Aero high voltage electrolytic capacitors. One has a slight dent.

My Atlas cap meter measures them at > 2600 MFD and .47 and .42 ohm ESRs.

Perfect for that HV tube power supply.

With new brackets.

$20 each set (1 cap and 1 bracket) + shipping

I have a 280VA main PT with 120v, 110v, and 100v taps on the primary. Using the 120V tap.

Would it be possible/advisable to use the unused 110v primary tap to apply a lower voltage to another PT (say a 35VA filament transformer?)

Effectively using the primary as an autotransformer…

Or will I risk burning out the windings between the taps?

Whether you are a highly informed connoisseur on a subject or a very smart person at all, it seems still not enough.

Your own experience is another important element to add, as well as your beliefs and the ability to face the "new".

Yet I know graduate engineers with top marks and industry experts at the highest levels of experience who are dumb, if you know what I mean.

Learning about the human capabilities is a wonderful journey, but there’s still something missing...

What makes someone a really special person?

Is anyone able to decipher this jumper diagram for a Broskie Aikido amplifier?

I have built the board with 6.3v DC H+ and installed jumpers J8, J5, J9 and J3 to wire the heaters in parallel exactly as John Broskie suggests. However, only valves V3 and V4 are lighting up.

Can anyone with a sharper eye determine if the instructions are incorrect or incomplete?

Crown D-150A II input sensitivity 1.4v ? Soundcraft MH3 can't drive it to full output. I think some bad luck on my part . I repaired the amp and set DC and Bias. All good but on my version of the PCB there is no way to set the input to .774v, Only the later version's have that. Maybe someone has some ideas? ?
My pcb has only one dual opamp and the layout is totally not the same.

SOLD.

Inspired by other threads, I designed my own version with two 12" car subwoofers. I plan to use it near field. I am curious how high it can play, I would like it to match my dual 3FE22 sealed boxes, which start rolling off around 150 Hz. Or my "Kallax" synergy horns, which should play even lower when finished. 18mm MDF, just large enough to fit the woofers. The chamber inserts are cut in parts to save material. I just need to cut one more side panel with a saw. I am curious how it will turn out.

Hello!

I'm wondering at the best way to ground 300mA heaters powered by a DC current source. I can see 3 options, probably there are many more. I use PL509 as an example, but this could be any P* tube:

I discard A, because the heater is positive against the cathode, and some datasheets only specify negative heater against the cathode.
Option B is fine, but we have both ends of the heater at a different voltage. Probably means nothing and it's a valid approach.
Option C is my preferred one, resulting in the same potential on both ends of the heater. There is, of course, a bit of current lost in the divider, and the resistor values are quite high.

I'm probably overthinking this, especially taking into account that P* tubes are designed for relatively high values of voltage tolerance between the heater and the cathode, but still would like to hear opinions, especially when doing tube measurements for gm, Ia vs Vg1 etc, like typically done in a tube tester.

Regards,
Jose

For sale my second pair of this superb drivers, used for about 6 months in monitor enclosures for back surround speakers and in top condition in original package. Price would be 300 euro including shipping in EU. Payment via Paypal. More info, plese contact me.

Just a simple question, if I've got a cm choke rated for 10amps at 300v there would be no problems using it for, let's say, 40amps at 24v?
Or there are some saturation mechanisms behind that I'm missing?

Works great! Shipped in the US for $200. This thing is a beast! 8" diameter, 3.5" tall and 29 lbs.

Can someone please tell me what type of ply I have here? If my pic works!

This r2r dac in aliexpress have trimpots, and picture enclosed. Anybody knows what's its for?

Hi

I want to install a pot to use as a passive volume control between a Cambridge Audio DACmagic 200m and a Aiyima A07 integrated amplifier.
The DAC has an output impedance of 50 ohms (I am using the unbalanced outputs).
The amplifier has an input impedance of 23kOhms @1kHz.
What makes my question slightly different is that the amplifier is mounted out of sight in a case (with a dedicated power supply), and I want to leave the integrated volume control at circa 50% so that kids cannot blow my speakers. I do not want to use the DAC volume control for separate reasons.
I am just going to use an APLS blue with less than 20cm of interconnect cable each side.

What value pot should I use?

Hi does anyone in the U.K. offer a build/design service ?
Thanks

Basically can I replace the one in photo 1 with the one in photo two? Thanks.

When I look at FR in a program like WinISD, do the T/S parameters for a driver help model the low end FR/Rolloff, or is the program assuming a flat-ish response driver and the box response is more of a contributor to low end roll off?

For example, when I take a driver, the manufacturer FR is this:


And when I do a basic modeling of that driver in an enclosure in WinISD, I get this:


So, at 25 hz, the driver in free air is down almost 10db from 100 hz, but in WinISD in a vented box example, the reponse is down only 5 db.
What's closer to reality?
The reason this matters to me: I'm looking at port velocity in a flared 2 inch port, and WinISD and Flare-It show I'd be in danger of chuffing at the power levels I anticipate, but at VERY low frequencies, like <35 hz. So I'm wondering if the port and driver will really be as excited below 35hz as WinISD models, or if the driver's roll off down there will make it lower than predicted?

It's possible to buy high quality aluminium cases on ebay/amazon which come from China. They fit together well and usually have output/input sockets and an on off switch included. There's a problem however - these cases are usually in sections and each part is coated in a substance that insulates it from the adjacent sections. Up to now I've spent a lot of tiiime rubbing off paintwork in a bid to try to make an electrical connection for the whole case and cross wiring between the different parts.

So my query is this - Is all this work really necessary? Does the whole thing have to be connected for safety and or screening?

I'm building a small enclosure for an 8 inch subwoofer. My goal is to make it as small as possible for the desired sub bass extention (32hz f3). I'm also aware of the internal bracing needed to avoid unwanted cabinet resonances and I have some metal available so I'm thinking of reinforcing the cabinet with it. Wood can work too and is more common but it also can ocuppy more internal volume.

My question is. Can this metal pieces interfiere with the magnetic field of the driver to the point where the flux is "weakened" thus making it less efficient or reducing sensitivity? I can imagine the magnetic field pattern can change. And the flux would go to the metal bracing (partially) if it's a bit close to the magnet, instead of concentrating the field in the gap/motor structure.

Hi all,

I'm putting together a series of laboratory experiments for classes I teach that involve several low-cost linear shaker motors - essentially high-excursion speaker motors with 8 ohm impedance.

Driving such motors is usually accomplished using laboratory grade power amplifiers with frequency response expending down to below 1 HZ. Those amps also run north of $3k for 100 watts RMS on a single channel.

My understanding is that DC amps should theoretically go down to 0Hz, which would enable a much lower cost solution. But nothing I can find on the market advertises a lower frequency response limit below 10 hz or so. Why is that? And is there any hope of locating an amp with a frequency response of say, 1Hz - 1 kHz?

Got one of these tweeters to play with. I noticed the voice coil is angled a bit. I know these things are rarely perfect but I didn't expect to see it this clearly by eye.

What do you guys think, is this going to be a problem? I feel like it might limit excursion if one side of the coil is in / out of the gap. I can not test it right now as I'm moving stuff..

Either way, I thought the photos might be appreciated.

I do notice that there is no damping material visible in the middle of the chamber! I assume there is some in the outer area that I can't see? Otherwise huh...

new still unpacked XP power ECL30UT03-P open frame AC/DC converter 5V 3A +/-15V 0.5A each, purchased from digikey $20 obo, 9pcs available
https://www.digikey.com/en/products/detail/xp-power/ECL30UT03-P/4487597

I'm a newbie, and looking forward to build a desktop speakers. Boenicke W5 clone thread got me interested. 🙂

Hey guys. I've been trying to get started programming the QCC5171 and since I'm locked out of the website's resources, finding info is pretty tough.

I've made a programming jig that people said has worked for other Qualcomm modules to directly connect it via USB, but nothing shows in device manager and there's no sound when I plug it in. Any ideas on what I might be missing? I have no access to the actual chip datasheet, so I have no clue outside of the module datasheet I was provided by the Chinese company I got it from. Even figuring out what program I should be starting with and how to set it up is proving difficult - but I think the answer to that one is Qualcomm MDE (seems to be where I would write the firmware, flash, and debug).

Hello Sub builders...

I have settled on a new mini project consisting of a BMS 12S300 in a very low tuned enclosure... BMS Specifies a 60L container for the given response with 110 mm / 517 mm long (presumably) circular port..

I would like a slot designed port and given my confused state i can't seem to find anyone coming up with definitive calculations for getting the correct port length etc.. maybe i am missing something. I have a rumour in my head the WinISD doesn't calculate specifically slotted ports.. maybe i'm being corrupted by something somewhere else on DIY.

BMS Recommends to use a port length almost half the size of mine and a circular cross section of 9500mm2, again thats almost half as much as my 21840mm2 (6X36X102cm) slot port.

Given the simulated response i just don't think i am getting the SPL i should be getting considering this type of driver... it has a super low FS. I have already tried to get more SPL out of the enclosure by increasing the volume by 8 litres...

I have attached some pictures of the simulated response with WinISD and some pictures of the enclosure... my instinct tells me that the port length is two small in width and too long in its entire length to the back.

The parameters as follows....

BOX = 67.8 L
Tuning Freq = 29Hz
VENTS = 6cm X 36.4cm
Calculated Vent Length = 102cm
1st port resonance 167hz (A bit undesirably low... LPF will be set around this point)

After putting together the box in CAD and calculating the volume displacement with the amp modules am i accounting for the rear volume independent of the port volume? i have tried to balance this with the suggested port length 102cm X width and size to somehow find the balance with a slotted port that will fit in unison with the suggested internal 67.8L.

Are there any subwoofer building experts out there that could at least help me approve what i have done as a valid design? I feel that i am overthinking things when in reality it could quite possibly be a bit more straight forward..

I really would appreciate any help where you can,

Lots of Kind Regards,

Dec

I am selling some audio transformers on Ebay and thought some of you might be interested.

I can give you a 10% discount if you buy directly from me (no Ebay fees) and pay by PayPal (much faster).

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So, buy with confidence.

Thanks for looking!

Looking to by a par but also interested if you just have one for sale. Thank you!

I was idly reading Robert Harley's review from some time back in The Absolute Sound (I wrote for TAS during the Harry Pearson days) of the Wilson Benesch Eminence, which can be yours for $232,000 the pair.

That review reminded me (I had reviewed three or four different Wilson Benesch models when I was writing for Stereophile over the course of 17 years) of something that I had forgotten:

That in many of their loudspeakers, including their TOTL Eminence, Wilson Benesch connects the midrange directly to the amplifier, letting the midrange "Run Wild."

Which means that the midrange (or a woofer-mid--WB's midranges are 7 inches) has to cope with all the bass the amplifier is pumping out, while the roll-off of the midrange or woofer-mid is at the top of its passband is purely mechanical and not electrical.

I recall being told the same thing about big Egglestonworks multi-way speakers.

I also recall being told that the very very nice ASA--Atelier de Synergie Acoustique--2-way monitors had a network only on the tweeter, and that the Dynaudio woofer-mids ran wild.

What I plan to do over the weekend is hot-wire the Eton 5-312 woofer-mid in my current prototype directly to the speaker terminals, with the wire running to the crossover sending a signal to the crossover, but with only the tweeter connected to the crossover.

Obviously, a woofer-mid in this circumstance is different from a "pure" midrange (I recall that WB's midranges use lighter cones than the same-size woofer-mids), but what I am describing is just about the same thing, as far as I know, as the ASA.

Furthermore, when I am breaking in woofer-mids, I run them wild in a literal shoebox (Kuru shoes) as an enclosure, and the upper-midrange performance of the Eton 5-312 so impressed me that I video'ed it! I urge everybody to listen to this: Login to view embedded media
In any event, Kate St. John has a lovely voice and a really subtle musical intelligence, and I give her two albums Indescribable Night and Second Sight my highest recommendations.

I tried to upload the album cover image, but the upload function was not cooperative, sorry.

So, just curious what other peoples' experiences have been, and I will update after I do my little experiment.

Thanks much,

john

I bought a pair of ESS Heil AMTs without realizing quite how heavy and bulky they are. So they don't work for my project but I hate to throw them away. I opened one and took an REW sweep, the other is unopened. You can see the datasheet here: Heil web page. I'll send them to anyone who will pay the cost of shipping and packing from zip code 89523. They are kinda cool...but odd!

Just completed work on the Burr Brown headphone application with the OPA2604.: 1k &10K, giving a gain of about 11. 10K shunted with a 100pF cap. and a 47nF/10R Zobel on the output. Works well with various types of headphones.
Unfortunately, the 2604 is now obsolete, the OPA1688 is recommended as a replacement.
This design relies on the high output current capability of the device, so BEWARE of non genuine parts!