Good Day,

I have designed and tested a valve heater regulator using a LM317 but am keen to use a LDO regulator (< .75V DO) to reduce both the component count and power dissipation across the regulator. Only caveat is that the heater voltage is elevated to 140V. So does anyone have any suggestion for a suitable regulator? The heater voltage is 6.3 V and there are two in parallel ie .6A although I can run them in series (12.6V @.3A).

Also what rectifier diodes are recommended, anything special or would the UF4007 suffice? One with a low forward voltage drop would be of benefit.

Thank you,

Hi everyone.I want to build stereo slim subwoofer towers with shallow subs.(want to add different bookshelfs,fullranges on sub towers in future)
https://www.intertechnik.com/media/1382436_124227.pdf
and
https://www.intertechnik.com/media/1382315_124171.pdf

It seems items are same except colors but black ones recommendation have 10-17 liters box and silver one has 40 liters.Is there any mistake with datasheets?
Regards

Hello guys,

first I would like to apologize if I did something wrong (put this thread in wrong section etc.), it is my first post in this forum.

Now to the point. I found similar thread on this forum yet my problem is a bit different. When I turn on the amp I can hear a little crack on both channels, therefore speakers are receiving some signal, however only right channel is working correctly. Left channel stays quiet until I crank up the volume to cca 11 o'clock which is really loud. Then both speakers are equal and everything is fine. Also if I unplug right speaker I can hear that the left one is playing music from cd player but it is VERY quiet.

Now I will describe what I did so far:
Checked all transistors on the output board, all of the output transistors are ok. Checked fuses, diods and all other transistors... everything fine. Then I moved to volume control / input selector board. Checked capacitors, couple of those smd transistors . Switched couple of those ICs which are right next to volume knob (yes I have SMD rework station) to see if different range of volume will start working but no luck... still same problem and at this point I am clueless. Is it right to suspect Z86E21F1 on HA7A control board ?

And also I was not able to find schematics for HA7A only for HA7Z :/ That is why I am running around with multimeter and going trace by trace, shooting blind what could be wrong.

I've already spent couple of days trying to diagnose this amp but at this point I am stuck and dunno where to continue or what to suspect, therefore a bit of help would be appreciated 🙂

Oh, and I am also using PSX-R alongside with Cyrus 3 but that one is fine. I "unmoded" the amp for just the wall plug but problem preserved. Then I switched back to PSX-R configuration.

Thanks in advance for any suggestion.

P.S.: if you guys will need more tech info please let me know. I don't have the amp on my hands right now (writing this from university), therefore I was not able to write which exact components I checked etc.

P.P.S.: Sorry for any grammar error... I am not native English speaker.

Hello guys, I’m desperate to find an original power supply for this amp. It was handed down to me and I listened to it all the time but my partner threw out the power supply by mistake thinking it was for the keyboard we were getting rid of!!! 😡

If they are pure unobtainium would anyone happen to have a circuit diagram or know how to make one?? I have done a little research and there isn’t much online wrt the power supply. What I did find is what it needs a 19v+/- ac supply.

Any help would be much appreciated.

Matt

FE83En sound is nice vocal.










FE83En sound at YouTube
YouTube Live Test-FOSTEX FE83En at 2.5 meter(Logicool C270n HD Webcam、PC、TASCAM 102i、AKG P220で配信) - YouTube

I just happened to be looking around at audio websites during the last few days and noticed that some new models have appeared at Audio Nirvana since I was there last. Most noticeably the 'classic' line has expanded to include 12- and 15-inch models, in both ferrite and alnico versions. In addition, there is now a whole range of 'horn' models that have very unusual cones, as if a horn was built in. I haven't looked at that website for a year, but I can't find any comments on these models so I'm wondering if these are actually brand new and no one's noticed? I'll provide links to the T/S specs to save everyone from navigating that impossible site. 😉

http://www.commonsenseaudio.com/an10classicalnicospecs.jpg
http://www.commonsenseaudio.com/an12classicspecs.jpg
http://www.commonsenseaudio.com/an12classicalnicospecs.jpg
http://www.commonsenseaudio.com/an15classicspecs.jpg
http://www.commonsenseaudio.com/an15classicalnicospecs.jpg
http://www.commonsenseaudio.com/an8hornspecs.jpg
http://www.commonsenseaudio.com/an8hornalnicospecs.jpg
http://www.commonsenseaudio.com/an4hornspecs.jpg
http://www.commonsenseaudio.com/an3cfspecs.jpg

What is the final solution for anti-pop during power-on AND power-off on these boards?
I've read more than a few threads searched on google and using DIYaudio search engine. Nothing seems like the final solution during power-on AND power-off. The cap/resistor/schottky diode solution seems to work during power-on only.

Don't mean to beat a dead horse here, but hopefully future google searches will illuminate this thread as the final solution after we get some good responses in here from current owners/DIYrs. Thanks!

Four new, unused Jensen Mic Input Transformers JE-115K-E (note: theses are the previous version to the current Jensen JT-115K-E, current price $73 each). Build a high quality mic pre with these, an NE 5532 IC, and a few resistors and capacitors.

I would like to sell all four together. Asking $100 for the four, including shipping to the US.

Please PM if interested. Thanks.

11/26/2020 ***SOLD***

“Hans: An eye for an eye leaves the whole world blind, I believe that wholeheartedly.
Billy: No it doesn't. There'll be one guy left with one eye. Hows the last blind guy gonna take out the eye of the last guy left, who's still got one eye! All that guy has to do is run away and hide behind a bush. Gandhi was wrong, it's just that nobody's got the balls to come right out and say it.”

Before someone takes out my eyes, I want to build a speaker so when the eyes are gone, I will have something to listen to instead of chasing the guy behind the bush blindly.

My first post here. So, not sure if this is the right place for this question.

I wish to build a bipole mltl speaker using full range speakers.

Late last year, I came across few DIY speaker designs and I was impressed with it. Furthermore, I am also impressed by the design of Apple Homepod and Sonos Sub desgin. So, I went ahead and build one small bipole speaker using cheapest that I could find locally, Dayton PC105 4ohms (PC105-4 4" Full-Range Poly Cone Driver - Dayton Audio) driver, two of them in one box mounted back to back. Initially, I went with sealed cabinet but than ended up drilling a large hole and put a bass port, and I was impressed with it. Bass went lower than what the specs said and what I expected. It is nice and punchy and clean. No lingering boominess. Well this was speaker made by what was available, no measurements or calculations were used to design the cabinet, just went to hardware store and asked them to cut a long plank in 5 equal parts for 4 walls and last part cut in half for top and bottom. Anyway, it was a good outcome. This leads me to building a proper calculated speaker cabinet with better drivers but 4 of them in one cabinet.

So, what I am looking to build is...

A bipole speaker with 4 drivers 2 in the front and 2 in the back in MLTL cabinet for better bass.
The reason I went for fullrange is to avoid any crossover designs as I am just getting into DIY and want to reduce any complications. I would prefer to use 4 small drivers (3" or 4" inch) instead of mid woofer and big woofer for bass extensions.

Any suggestions on drivers to use. Any suggestion on speaker cabinet designs and cabinet measurement calculations and etc. What about the power requirement, I assume using 4 speakers in one cabinet will require more power.

Appreciate your help.

Hi all,

I'm building speakers with 3 drivers (treble, mid, bass) and bass port.

There's a multitude of info. here on various x-over designs, I'm looking for a passive system with linear response that might be avilable as a kit or at least based on an existing PCB. The speakers will be ~150w, 8 Ohms.

Words mentioned, I've seen 'eliptical' plus various 'orders'...

Any takers?

See my Audiogon ad. $1250 plus shipping.

Rare class T (switching class D) Tripath-based amplifier.
Excellent sounding amp. I have moved to a Class A stereo amp, so I am parting with this one.

I purchased it used from a hifi shop. It was advertised as from a non-smoking home and I also live in a smoke free/pet free home. Very clean with no marks on the face plate and very good top and sides and rear (see pictures).

It has served me well and I am certain you will be happy with it.

The 150.2 produces a strong 150 WPC into 8 ohms, and 300 WPC into 4 ohms. BAL and SE inputs are provided, along with a 12V trigger and detachable A.C. power cord.

Like the 150M, the 150.2 produces very little heat because of its high efficiency, so it is ideal for in-cabinet installations.
International buyers will pay actual costs for shipping

Hi all of you.
I bought 4 Scan Speak 15W/4524T02 at 4 Ohm. I am building a two bookshelf boxes with 2 mid woofers and one 8 Ohm tweeter. Should I just double the box volume designated for one speaker and should I just double the port area and keep the same length?
Thank you in advance.

The pandemic has left me with a backlog of 12 drivers which need surrounds. Normally I am quiet fearless about such things but all 12 are vintage drivers which need to turn out well. 4 of them are bentrene (polystyrene) ESS drivers. I have not shimmed before. Advice? Good shimming videos? Specific experience with bentrene drivers? Thanks

When you bridge an amp normally you feedback each branch individually and it gives what it gives. This type of error corrector acquires differential output and provides correction on one side only. To show how effective it adjusts, I take a VAS stage of gain +/- 5 on each branch to drive a nonbiased low quality pair complimentary transistors. One side receives directly the input where the inverting side receives corrected signal.

With 10v output I get a distortion of 0.04% with 10khz and perfectly stable.
The result is superior with AD8008.

Hayk

The pandemic has left me with a backlog of 12 drivers which need surrounds. Normally I am quiet fearless about such things but all 12 are vintage drivers which need to turn out well. 4 of them are bentrene (polystyrene) ESS drivers. I have not shimmed before. Advice? Good shimming videos? Specific experience with bentrene drivers? Thanks

I've had a pair of Epos ES12s for a number of years, and always loved them.
Recently bought a second pair for my girlfriends cabin, along with the stands.
The seller stated that he had replaced the front baffles/mid drivers a few years back due to rot. Figured, great, already replaced and newer-ish, well cared for.


When I got them, I noticed the speaker was totally different Epos molded unit, composite I think.


Attached is a photo of two different baffles: the newer one in the foreground and the 'older' one from my ES in the background.



The newer one is much larger, but feels to be same weight and stated specs. The rest of the baffle is exactly the same.



Anyone have any ideas the differences in sound, is the newer much better than older? I am afraid my set up and space don't lend to really tell a large audio difference, but it sounds as if the newer ones are.....cleaner, sort of? Brighter? More detailed but slight sound of tin can compared to my older ones.



Thank you!!

So, I run a sound company that hugs the line between DJ work and the corporate/live sound world. I've also learned if you have time & money, it's wise to spend what you have most of, and due to the Covid thing, I obviously have more time. So, I've spent most of this year building speaker cabinets & gear racks in anticipation of the day they actually can get used.

Just like everyone else though, my business isn't making the $ I thought it would this year & 'adapting to the new environment' instead of waiting for the environment to get back to normal is what seems necessary lately. I've been analyzing through what aspects of my company could make money on their own, because there simply aren't any audiences to put a PA in front of lately.

Anyway, I have 2 different ideas that I believe would work:

#1 Buy/build a CNC setup: Put it to work making knockdown cabinet kits for DIY kinds of people. That machine could also (possibly) source work from our local construction industry, and maybe make artwork for Etsy or something like that. Also, it makes sure the audio side of my company has a bottomless supply of speaker cabinets, I'd just have to buy drivers & amps 🙂

#2: Spraying U-Pol Raptor (or similar): This is the goop I've been spraying my cabinets with, and it's actually a DIY bed liner for pickups. Pretty sure it wouldn't be difficult to post a few pics online & get the phone ringing to refurb speaker cabinets, car sub woofer boxes, jeep bumpers, tool boxes & whatever else can fit in my limited spray space. I'd shy away from full vehicles & pickup beds though, I don't have the space & there's other shops in town that are better set up for that.

The CNC idea would require some $ investment on my part and time to get going, but it wouldn't necessarily be limited to local business. Shipping could make it workable for people all over the countryside. It also doesn't require a ton of my time once the machine is cutting up a job.

The idea of spraying Raptor has basically no barrier to getting it going, other than the willingness to do it. It also has the downside of it wouldn't make a nickel without me actually doing the work, where the CNC idea can to an extent. It also would be limited to a more local market I'd imagine.

So my question is this : Which way would you focus your attention on? Do you see another idea I've missed?

Thanks in advance!
Todd

Hi,


some resistors in tube amplifiers need to be able to handle some higher wattages, as you know. Is there any reason, why I shouldn't combine resistors to increase their max. power values? Or doesn't this create any difference or dangers and I don't have to buy the whole range of high power resistors of any value to be able to experiment at home without waiting for ordered parts all the time?


Thank you!


poppy

1.1" (29 mm) Soft Dome Tweeter

Bold North Audio Releases Soft Dome Tweeter Completely Designed and Assembled In America | audioXpress

Its nice to have a tweeter that is built in the USA. The price also seems to be reasonable, compared to the European ones. The manufacturer claims that this tweeter can be used down to 1kHz. Do you think that we really use this tweeter down to 1kHz using a passive crossover?

Bought a pair of these Dutch Masters from the local classifieds and, well, discerning audiophools best look away now, I stuck them in the worst enclosures thinkable. That's right, just some cardboard removal boxes. Yes, it's a bit like drinking a vintage Claret from a plastic cup (something I may or may not have done in the past...), but cheap and cheerful fun.
IMG_7688 by ctjr, on Flickr

IMG_7690 by ctjr, on Flickr

The verdict? These drivers have a very special sound all of their own: excellent drivers, not exactly neutral sounding but very nice for the stuff I like to listen to (and more besides). The soundstage is huge, the imaging is good too and, surprisingly, the speakers are hard to locate when listening with closed eyes. These speakers have no right to sound this good under these circumstances, yet here we are. The cardboard boxes act like a slightly undersized leaky box (just like many historical enclosures were build for these drivers); a very promising direction to look when it's time to build them some proper cabs

Bass, obviously, is not earth-shaking, but with floor coupling and room modes in a square 4x4 m, the bass is very, very acceptable. I ran a few frequency sweeps and the drivers comes in at around 40-45-ish (just like it says on the tin) and already produces quite a credible sound at 60hz. Nothing earth-shaking, but then again, that's neither useful nor desirable in a small city apartment build before sound proofing was a thing.

Anyway, lots of interesting possibilities with these drivers, they're definitely keepers.

Check this out: So as you can see, the far speaker is toed out while the near one is toed in significantly more than the other is toed out. My point is this is where they have to be to project a perfectly coherent sound stage where they disappear and only the music remains. 1/8" deviation by either and the image disappears. Very strange. I stumbled on this positioning while incrementally toeing them further out. I was not paying attention to symmetry but rather that they faced my listening chair at the same trajectory which is a bit off to the left of center. I knew this. When I adjusted them to zero toe in/out since they were so close and moved my listening position to center, it ruined the image. Is it possible my listening position is coincidentally exactly where the room acoustics place the sweet spot relative to where the speakers are located? These are Acoustat Monitor 3 ESLs. Both are exactly the same geometrically with no defect. I suppose my question is..can the room dictate speaker positioning regardless of symmetry?

Hi Everyone,

It's been a few years since I did much electronics diy, or posted on the forum, but I've recently been doing more, including the kit from the diyaudio store of Nelson's new crossover; I'm also planning a new FW amp build, maybe M2X, maybe F3, to use with it.

Searching out parts I came across a big toroidal transformer from a surplus site, which was cheap because it had few markings. I bought it on impulse, thinking I might need to rewind secondaries and that they might be fun (at least once). However after checking it out I'm wondering if I might be able to use it without doing anything. I've attached a couple of photos below.

It was sold to me as 1000VA, but I doubt it's as big as that. It weights about 11 or 12 pounds, is 5.5 inches in outside diameter, and about 2.5 inches high, so judging by this and other sites on the internet (like Rod Elliott's ESP site) it is more likely be between 500VA and 800VA. Which is still pretty big.

The side I presume is the primary (black/brown/white) has dual windings, each measures 2.6 ohms across black/brown, 2.2 ohms between black/white, and 0.6 ohms between brown/white. (This doesn't add up, but my meter may not be perfect, of course. Or maybe it's to be expected on a transformer.) The other (presumably secondary) side has four windings, all measuring the same, higher resistance. (Can't remember the value without checking.) Two are red/black, two are yellow/orange.

I tested it with a small AC voltage and then scaled up slowly. It turns out that if I connect the two primaries in series then each secondary gives slightly below 18V, which seems close enough. I used a modest load - can't remember precisely - so there was a reasonable current draw.

The plan is to wire the primaries in sequence, with a CL60 between them, as Nelson shows in his article on several FW amps. 110 V on this side, from the wall. Each of the secondaries would have its own rectifier bridge, and then all four would connect in parallel to a filter. With a little luck a big CLC filter, but that's not really relevant. (Although I note that in a thread of mine from a few years ago AndrewT said when secondaries are "bifillar", whatever that means, you can wire them in parallel to the same rectifier.)

So here are my questions.

1. Is there any reason to think I have it the wrong way round, and this is some sort of transformer to scale low to high voltage? Doesn't seem likely - just thought I ought to check. The "primary" side has the clips shown in one of the photos, if that helps.

2. I doubt I'm proposing to wire the primary side the way it was intended. I don't think this makes any difference, does it? 110V on the primaries in series will produce half the voltage in the secondaries that 220V would, which was presumably the idea. So as long as I don't draw more current than is safe then there should be no problem, right?

3. What would the purpose be for the off-center tap on the primary side? I'm not planning on using it, but I'm curious.

4. Any reason my plan for using this in a stereo FW build wouldn't work? If so, is there any advantage to wiring the secondaries in some other way than what I propose?

Thanks in advance for any input.

Best

Nigel

I have some 3 way towers that I would like to convert to 3.5 way actives. Any recommendations for DSP to use? My receiver's pre-outs and my amplifier inputs are un-balanced RCA jacks. I don't have a computer connected to my system and I don't want to add one. This is for home use in my living room. Here is what I'm considering.

freeDSP Aurora - I like it the best, but I have to pay for shipping from EU, I will need to add a lot of parts and time to make it work. The analogue inputs and outputs are balanced so I might need to add buffers to make it work with my un-balanced equipment.

MiniDSP 8x8 HD - Has everything I need but there is no way to access the DSP directly with Sigma Studio. This might not be necessary, also I see some posts saying miniDSP products have low quality ADC and DACs, not sure how much this matters in the real world.

2X miniDSP 2x4 HD - A little cheaper than the 8x8 HD, but managing two devices might make paying for the more expensive miniDSP a better solution. Same pros and cons as the 8x8 HD.

Something else?

Choosing the final parts I need to order for my SSE and working out pricing for various OPT options. One thing that really makes a difference is shipping charges.

I stumbled upon some relatively ugly 5k into 4/8ohm OPTs on ebay from China. They are described as "8-10 watt" and the specs match up approximately with the Transcendar 7 watt units and they are close to the same size as the Edcor XSE 15 watt units but the Chinese ones have a considerably thicker stack (35mm vs. 27.7mm). I have determined that 4-5 watts is about all I need 95% of the time.

I've made an offer on them and if it is accepted I will end up with two of them for $60 CAD including shipping. For comparison, the Edcors would be more like $130 CAD including shipping.

Believe me when I say, I do not have any expectations whatsoever about these OPTs. I know George stated on his site that people are unlikely to upgrade OPTs so they should buy what they really want the first time. Well, if these OPTs are crap, I will have no qualms about pulling them and upgrading to Transcendars.

This is basically just an experiment, with the benefit that it will expedite my ability to build and bench-test my amp. I'll update this thread when I have some experience with the OPTs.

What might cause noise like this? Class D amp.

Can't hear it on monitor speaker, just wondering?

Hello!

I am building a simple, cheap-o sub, something to cover the 35-100 Hz bandwidth. I am using the following speaker, Onkyo W20170A:

8 inch
Qms: 3
Qes: 0.372
Qts:0.331
Fs: 39 Hz
Vas: approx. 59 liters
Power rating: 30 W

I have placed it in a ~33 liter enclosure, with a 7.5 cm diameter vent, tuned to 35 Hz. Earlier it was tuned to 28 Hz, but there was a significant loss in power handling. Now I have tuned it to 35 Hz, there is an enormous hump (audibly) on about 33-34 Hz, and a huge loss on everything between 38-53 Hz.

Given the low Qts, should I tune it higher, like at Fs, or is there another issue? It seems what's happening is what you call "loss of headspace" for the bandwidth between the vent resonance and the -3 Db point at 55-60 Hz. Ideas?

Thank you in advance.

Hi,

I'm looking for internal photos of the DAB module that's inserted into the back of the DRA-700AEDAB AV receiver. The service manual sadly doesn't include the DAB module's circuitry. If anyone has the schematics for the DAB module, that would be even better.

Thanks so much in advance!

Sven

Looking for a pair of the BEX4008 or 16, if anyone is looking to sell. Thanks!

Hello all,

I'm thinking about linear power supply improvement.

Rectifying 3 phases transformer is better than single phase one because we obtain quite DC voltage without any smoothing. So if we use 3 phases transformer and then smoothing capacitors, the ripple quality will be far better than single phase version.

The problem is that in domestic use, we have only access to single phase AC.

What do you think about the usage of a Variable Frequency Drive (VFD) unit to transform single phase to 3 phases AC before supplying a 3 phases transformer ?

Another benefit could be also to increase the frequency of AC lines (up to 400Hz ?) in order to reduce more the ripple with same amount of smoothing capacitors.

I know that VFD generates shopper DC but do you think that transformers could handle that and smooth the current to have sine wave current at secondaries (as AC motor) ?

I thought I could just send a DM/PM to a mod, but that option doesn't appear to exist...

By which let me clarify, to include eARC from my TV, Airplay, HDMI input for a disc player, remote volume control, and room correction. And hopefully not spending a billion dollars.

I want to run a system of fullrange very efficient 2-way woofer/horn combos, maybe needing subwoofers and therefore possibly 5.1 bass management, and something like Audyssey/Dirac to fix the high frequency response droop of constant directivity horns. My default and seemingly cheapest idea is an AVR with preouts, AVR powering woofers and DSP amps powering the horns, the DSP providing highpass crossover and time delay versus the woofers. This is a little kludgy as it makes an extra A/D-D/A step.

I know miniDSP (and I presume others) make a variety modules. But is there any way to really do what I want without buying a expensive AVR or pre-pro? Or might I just as well stick to my kludgy plan?

The earpads for these headphones are smaller than what is commonly listed on eBay. They are 2.5"W x 3.12"H.

Where is a good source for Sony replacement pads?

I've been toying with the idea of building a 3-way speaker based on Troels Gravesen's CNO GRANDE design CNO-GRANDE for some time now. Why not build the CNO Grande you ask? Three reasons basically. Because I want to use some drivers that I already have on hands, because I'm not interested in overpaying for the kit from Jantzen audio, and lastly because the crossover values were not made public, so I'd have to reverse-engineer it anyway.

The CNO Grande is using the following Seas drivers: two W18NX001 woofers, a modified Seas W12CY0003 mid, and a T29CF002 tweeter.
E0042-08S W18NX001
E0044-08S W12CY003
E0040-06 T29CF002

Here is a link to the modifications to the mid driver: W12CY003

I'm guessing it's a few coats of surround glue applied with a brush, with the driver sitting on a low rpm turntable. I'll be doing these modifications myself, monitoring the results via measurement.


My design will be using the following drivers: two Seas U18RNX/P, a modified W12CY0003 mid, and a Morel ST728 tweeter. I'd get the enclosure professionally built, I simply don't have the time, space, tools, nerves or skills for that, sadly.

http://www.seas.no/index.php?option...e&id=102:h1571-08-u18rnxp&catid=44&Itemid=461
E0044-08S W12CY003
https://www.morelhifi.com/product/st-728/

Why this selection?

I currently have a TQWTL running the U18RNX/P and ST728 combo (factory matched tweeter pair), so I already have like half of the drivers.

And I'm convinced that the U18RNX/P is a better driver than the W18NX001 (W18 in black, U18 in red, matched sensitivity; look at the FR spikes in the W18 graph).



The ST728 looks better too. In my current 2-way design it has astonishing, near-constant directivity, resulting in a rock-solid stereo image. (T29 in black, ST728 in red, matched sensitivity)



I tried to model the crossover in VituixCAD using traced SPL and impedance curves, which are attached with this post (CNO_clone.zip). This is what I have come up with so far (XO points at around 1kHz and 4kHz, notice the 21mm setback of the tweeter):





I'm not sure I like the group delay and phase response.

I realize that the simulated response is not going to match the real-world, nor the in-box response, and much less the in-room response, but I have to start somewhere. The modifications to the W12 aren't taken into account either, obviously.

Now on to my questions:

How should I go about translating the simulated crossover into a real world build? I have a UMIK-1 and REW, so I can make basic measurements, although I have yet to spend more time with it.

Does the crossover topology make sense for my driver choice? Any criticism is welcome.

I really hope to get a discussion started, so any input is welcome.

I've already started building a small sealed standmount mtm, similar in layout to the old AE-2 but w very tightly grouped drivers. I'm using a small format tweeter and 15W rev's.
Any issues with the midbass drivers being so close, 1cm gap? Ie vertical sweetspot.

Q150 Bookshelf Speaker | KEF

Going to remove the drivers and XO to put together a rather tall MMUMM with 6” woofers and an active filter from woofers to the UniQ.

Will post some measurements once the Kefs get here and I get them apart.

On request here’s the builders thread for the assembly of the Inverted J-FET Circlophone.

The Inverted J-FET Cirlophone PCB was initially strictly intended for personal use only, but after several private requests over time I decided to make it available for the DIY community.

The component placement document (PDF) with reference designators matches the schematic.
The silkscreen (component) values on the inverted J-FET Circlophone PCB correspond with the schematic and are all correct, but the reference designators DO NOT match the attached schematic.
Cross-marked components without component values are ONLY for experimental use and/or a different outputstage configuration.

Highlights of this version:
Scalable outputpower, rails up to 50V
JFET input, (virtual) absence of gate/base modulation
Improved step response of the CFP configuration
Reduced phase inverter dissipation
Original Circlophone features:
No (very low…) cross-over distortion, semi class A
No need for thermal tracking the output devices
Idle current 200 mA, Gain : 28 dB

Long shot here, but I'm in need of 2 power transformers, one for a 222C and the other for a LK-48. As it works out, they're both basically the same power transformer. I have one of each amp here in my home for repair / refurbish, and neither even have the old 'dead' PTs on them. So, I don't even have a decent core to send in for a rewind. As such, I'm looking for 'dead or alive' units. ANY help here would be greatly appreciated! Many thanks!!

Tom D. - Wharfcreek@Outlook.com

Has anyone brought one of these. I should get one in the next day or two to assemble. It took a long time to get delivered because the 1st one shipped got bounced back to the seller.

I was looking for a low power reasonable performing 2 channel amp to run my tweeters in tri-amp speaker. The specs aren't the best, but seem ok if you don't push the limits of its power. I doubt if I would use more than 10w peak. The reason for this choice it is seems to have speaker protection that I hope works during power on and power off cycles. Going to use a 100VA 36vct transformer with it. After I bench test it if it works well I have to find a case and heatsink for it.


2018 GC version LM4766 dual channel HIFI power amplifier board diy kit | eBay

I'm not sure what is wrong with this amplifier, it Powers up and has a different curcuit than the cxa amplifiers. There is no output at the speaker terminals.

Hi,

I recently bought a paire of Onken enclosure for Alpair 7.
As I had already built FH3, FHXL , Pensil, I wanted something different and decided to buy a pair of MAOP 7...the last project ;-)
Well, not sure if I want to keep this enclosure or go back to FH3....I may be tempted by a WAW project.
What are the best option regarding the onken enclosure?
Keeping the Onken and build another onken WAW?
Or a brand new project?
Crossing must be analogue
Thanks for your help.

Ok after hooking up my old record player for the first time in 23 years I was very impressed by the sound of it. (using an old pioneer receiver for phono stage).
So I decided to start picking up vinyl. Bought an old thorens td 125 turnable but now I need a decent phono pre.

I wanna build the Aleph Ono with mc part included.

I got a pcb layout and Bom from another forum very kind forum member (sylvian bergeron) . But these are in dns format which I can’t open and even if I could I don’t have any experience working with pcb routing software.

They are mono boards
It is a version without output capacitor.

The power regulator and power transformer are on separate pcb’s so it is’ actually the xono version.
I will make these two relative simpel psu boards just the old fashioned way with a permanent marker.

there ’s a company here in the Netherlands that can make the pcbs for the main amplifier board.

They charge me the following

PCB 220x115mm - finishing with HASL, Green soldermask, White component printing

45 eur for converting DNS to gerber RS274X

2 pieces for Euro 99,42 (per print €49,71)
5 pieces for Euro 136,80 (per print €27,36)

Delivery Euro 6,00

delivery time between 1 and 2 weeks

And underneath the actual questions:

Is there anyone one out there who owns a set of pcb’s that you are willing to sell or know where to by them?

Is this a competitive price and where in the Netherlands do I get a better deal?
would anyone be interested in pcb’s?
(so I can order more pieces to reduce costs)

Ok that is a long story for some simpel questions

Anyhow awaiting yourrespons

I ordered two 2x10" sealed vertical cabinets that will serve as both subwoofers and stands for a pair of bookshelf speakers. I am buying a Minidsp SHD and will be using room correction and active crossover between the bookshelves and the subs. I will be playing around with different crossover points and curves to find what works best for me, but I think I will be somewhere in the 250-500hz range.



Are the Peerless by Tymphany 830668 are a good choice for this setup? Are there better options out there for the price, or will these do just fine? The enclosures are 2 cubic ft a piece, so 1 cubic ft per sub.

Hi, Gang,

I'm redoing my PAS-3X and will not be going back. But - I know someone who wants to keep the tone controls prefer the 3X versions as they are out of the circuit at center position.
I'm including the local caps and knobs, to be fair, the knobs are pretty ratty but I think they should go as a set.
I'm not sure what a fair price is, so here goes - $35 + shipping, or best offer. If these sell today, maybe I was a bit low. And seriously, if I'm out to lunch on my pricing, feel free to let me know.

Thanks,
Frank

FS.GENUINE PETER DANIEL AUDIOSECTOR LM3875 KIT ASSEMBLED BOARDS PLUS HIGH QUALITY CASE.NEVER USED.COMLETE WITH INSTRUCTION MANUAL.JUST ADD TRANSFORMER.UK/EU SALE ONLY.£85 plus postage at cost.

I want to ask about the corona wind type plasma,like the Plasmasonic headphones or the Nelson pass cloud speaker,I believe the Corona tweeter from Lansche is the same type,its corona discharge that is modulated push pull from both sides by electrostatic force,like a Stax but instead of membrane there is plasma.

its different from Alen Hills Plasmatronic /Magnat sphere tweeter/Ionovac,these are glow discharge that makes sound by getting bigger hotter and then cooler smaller.This is picture of the Plasmasonic headphones

My question is,how can this "corona wind" type plasma device work? I learned that the net charge of plasma is neutral,so how can the push pull stators push it with electrostatic force if the plasma is neutral?

When I imagined it in my head,when one stator is negatively charged,and other positively charged,wouldnt the plasma cloud go both ways?! I mean the negative charged particles in plasma cloud go in the direction of positive stator,and positively charged part of plasma goes the other way towards negative stator,my thinking is probably wrong?


Is it possible to make the plasma cloud have net negative charge instead of net neutral?

I have one pair of the SB Acoustics Satori MW16PNW-4 for sale. This is the 6 1/2 inch white cone mid-woofer, 4 Ohm. Asking $150 US; I will ship for free inside the US only.

I have one pair of the Aurum Cantus G3Si ribbon tweeters for sale. Asking $150 US; I will ship for free inside the US only.

Neither of these have ever been abused or over driven. They have never been soldered.

I doubt I have the original shipping boxes but I will very carefully pack them and double box them to keep them safe.

I have a PayPal account; please send me a Private Message if seriously interested.

1 pair gently used, never soldered SB17 CAC35-4 Mid Woofers.

Priced at $86.50 each on Madisound, etc.

Asking $150; will take serious other offers.

Great for a 2-way or even very small 3-way; very low distortion, ceramic coated aluminum cones. These are 4 Ohms; works well in closed box 7 liters and up; works well vented in 18 liters and up.

I agree to pay shipping but ONLY inside USA lower 48!

PM for SERIOUS inquiries ONLY!

Hello,

I'll be building a new set of cabinets, the same as my last set but they weren't didn't fit as tightly together as I would've liked. So I'll be building another pair which will then be veneered and finished by Boesch who usually renovate and finish classic Rivas.

When I was putting together my previous pair and I was fitting the Silent Coat butyl damping sheets I noticed that it didn't actually make that much of a difference at all when I gave a knock on the wooden panels. Do you know at wat sort of frequencies butyl damping is most effective? And what are the most effective damping compound to fit in different chambers of the speaker? What would be most effective in a bass cabinet (20 - 300 Hz) and what would be most effective in midrange chamber (300 - 3.000 Hz)?

Would like to hear your suggestions.

Thread closed.

I have a built SB15SFCR39-8 passive woofer that I no longer require. It was built Jan 2020 to test the woofer and then used in a small 2.1 system. The enclosure has been built with an industrial theme, removable baffle and uses birch plywood coated in clear matt polyurethane. It does not include the isolation feet (in pic) which have been replaced with nail in nylon floor protectors.

This is not a subwoofer but a woofer for use in a small to medium room partnered with small speakers to make a 2.1 system.

Woofer SB15SFCR39-8 which is equivalent to a 7" woofer and has been coated with Visaton LTS50 to protect and dampen the cone.
Vb=23 litres, ø63 port, Fb=33Hz, F3=41Hz, F6=34Hz, SPL=87dB, rated power 60W.

There is no crossover, active filter or amplifier and would be suitable for a builder of electronics who can build a sub processor (stereo-mono mixer, filter, gain, phase) and a small power amp. If a passive xo is required then a filter using 22mH + 100uF 2nd order works well.

Pick up only in the Newcastle NSW area (close to Belmont).

I have had the folly to bid and buy the following turntable but realised (too late) that the output cables may not be at all the standard ones but instead the Hypertac ones. I am not an engeneer and therefore would have no idea how to connect them to my Rogers Ls 5/8.



Can someone tell me whether the unit has normal output or only the Hypertac one ?


Thank you very much !



Having forked out 2200 UKP you can understand that I am rather worried ...



Alexander , the audio fool

Looking for one or two pair Acoustic Elegance Dipole 15. Paying with paypal.
I prefer a seller from Europe. Please PM me.

Thank you!

Andre

Time to break down and upgrade my old Tek scope. It is great, but I really want a storage scope. Don't need it fast. The last storage scopes I used were still phosphor storage (mainframes and 466)

Looking at auction offerings,
Tektronix 2000 series, much older, controls like on my old one.
Tektronix 300 series, circa 93-94 or so. CRT based
Tektronix 1000 series, the newer LCD based
Some HPs, but I know little about them. Always had Tek back in the factory. Some newer off brands, but I know zero about them.

Then there are the PC based USB scopes. We get a bigger screen of course, but do they really do the job of a traditional external trigger, delayed sweep, storage etc? I guess as slow as 20Mhz would be OK.

The "boss" wants me to spend less than $200. Just outbid on a 1002B last night.

I'm looking for a very simple DSP crossover. I have found trigaudio and I am negotiating with them. They normally sell in MOQ 300, and I need maximum 20 (for reselling in my small DIY shop).

Are there any other alternatives. I'm not looking for a MiniDSP competitor, but just a very basic board.

Dear members,

Because the original plate amp from Final S220 subwoofer died, I ordered a Hypex FA251 plate amp. Not knowing there are no filters installed...... I read the manual and searched for tutorials but I haven't got a clue what to do😕

First of all, do i need measurements to design the filter or can i use some sort of default settings for subwoofers?

I attached the specifications from the manual.

Thanks in advance.

Barry

Well, 2 months after warranty has ended my power supply stopped working.
I replaced fuse and found it still not turn on and had a bad smell to it. So I opened it up and found C3 completely burnt out and cracked. Does anybody know the value or has schematics?

Thank in advance
Neville

Hi.I found these drivers on taobao com. Do you think they worth the money ? Does anyone have experience with them?
Here the drivers
https://world.taobao.com/item/528908373538.htm?spm=a312a.7700714.0.0.HxRUd3#detail

https://world.taobao.com/item/531656628653.htm?spm=a312a.7700714.0.0.MLY787#detail
Best regards

Hello, asking for help please in trying to identify a kind of subwoofer I've seen in the past and remember vague details about.

It has like a curve sided V in the front of the driver. Not fully enclosed. I believe it was first worked out by a Dutchman? Used in the 1950s originally.

Thanks!

Hello all,everybody.
I was asked to repair a previously repaired Audison lrx 4.000.
What are its original mosfets? where can I find the wiring diagram ?

Thanks

OB/FR is where I ended up finding myself seeing 'Nirvana' after much experimentation and study. Simply my preferences, not necessarily anyone else's Cup of Tea. Still crazy over Horns, simply no room for them.

I'm an admitted Couch Potato when not online or working so HT is important to me as well as music. My music takes preference regards quality of sound and a year ago I saw myself needing separate systems for each. When I started studying amplification I also saw myself investing bucco dollaro to meet all needs.

Of late I'm wondering if all this is necessary for those of us of meager means.

I'd like to see sensitivity of high 90's for music just because of distortion concerns, not because I'd seek lower powered amps. Subs don't really concern me that much as to my way of thinking I see all kinds of options there that I believe would integrate fairly well for Movie use and I personally don't need to rattle the walls for entertainment when a helicopter flies over. Again, simply me.

Some guys run tubes for both music and HT. Out of the question financially for many of us as well as beyond our DIY skills for many. I'm not seeing GC as a meets all needs alternative anymore and even done DIY properly not an inexpensive task. I do like them as alternatives to standard fare for Office use and plan to limit my excursions there to that purpose for near future. Of late I'm also over at Nelson's page primarily spurred on by Scott Mouses comments regards build difficulty being easier than many GC's in another thread. I'm also impressed as to how many testimonies from guys believing they sound just as good as or even better than tubes. They are still beyond my skill levels without a good deal more reading. Financially appears to be doable.

Stay with me on this, I'm getting there.

Posted in another recent thread I bring into play the multi amp units from Emotiva, Outlaw, Rotel and even used Bryston. You can't knock a 20 year transferable warranty. 3 years old Brystons are fairly affordable and most that invested that initial sticker price likely treated such as the investment they were.

I don't personally know tubes but all that run them claim this is the ultimate. Financially I'm starting to see these above mentioned units as 2nd. best alternative and combined with high sensitivity OB/FR speakers a good bet for both music and HT . I haven't read a great deal about each companies processors but I'm sure there is a Sub out and if not many are versatile enough in hook-up options to get you plenty of power for Subs unless you simply must have 20hz. at 110 decibels.

Adding an active XO and equalizer if individual felt such necessary (I'm not convinced, especially if you used dual Subs, think gain settings likely adequate) should integrate well enough to give you a pretty kick tail music and HT system for reasonable dollars.

Many guys are posting low buck OB efforts of late but some don't meet both needs and several that appear they would aren't telling us how they are powering same.

Moderator - Asking much but could we see a separate gallery section for OB efforts? It's growing rapidly.

I'd like to hear from those of you who have built that are happy if you believe your choice meets both HT and Music needs as well as how you amplified. Kind of a dual topic question but really a combined question I thought answered best posted here.

Move it if you desire.

Show off guys - please. Many of us want the whole story.

Thanks - Bluto

I'm trying to design a sub-sofa subwoofer using the RSS265HO-44 and can get what seems to be a nice enough power response using the LS wizard by tweaking the sliders and adding polyfill etc, but a pretty ordinary power response overall when I go back to the main screen.

And that's after 'saving' the response in the LS Wizard.

Can anyone tell me which is likely to be more representative of the real world response??

Auditorium 23 Hommage Cinema loudspeaker | Stereophile.com

Link above. Can someone explain to me the midrange horn expansion? From the outside it looks like a parallel wall tractrix deal with the compression driver just dumping into the back end, but that cannot be the case, else it would have some high q tomfoolery in band.

Is there an initial expansion that is folded inside that I can’t see? Any guesses?

Edit: oooh is there an expansion that passes down, through the final expansion, into that horn ‘base’ then curves around to the back of the final expansion? Like one of those western electric horns that passes through itself...??

Hi,
I have pondered a more powerful single ended design than the SE El509 in triode or SE300B'

Both the 6C33C and GM70 are capable of at least 15 - 20 watts

The GM70 run at lower B+ say 750- 850v DC appeals to me

I have some 6C33C tubes but read they are problematic to balance and stabilize .

Welcome idea's on this issue and driver tubes used .

I learned from Morgan Jones Valve Amplifiers that the min current required for choke input is approximately equal to Vin(rms) divided by L(H). That means as the current is lower the induction has to be higher. I wonder if this formula still apply if chokes are in series and using the total induction summed up??

Hello

I am looking for the datasheet of this DAC because I want to tweak a Audio Alchemy "Dac In The Box". I want to know if I can supply it with +- 12 V in the analog part.

Thanks

Philippe

CEC (C.E.C) claim by their mostly amplifier models, it's class A (here in Germany even "Pure Class A") The name of circuit topology is "LEF (Load Effect Free). The developer is Mr. Carlos Candeias. Have a look to this URLs: Amp 3300R:
CEC AMP3300R
and Amp 5300R (Amp5300R Amp 5300R Amp5300)
CEC EUROPE WEBSITE
The last model delivers 120W/8 ohms and 135W/4 ohms, as to read in the CEC datasheet
If anybody can posted the schematic of one of both models, I will make an evaluation. I guess, the term "Pure Class A" is concerning the pre-driver stage and driver stage of a push pull complementary CFP resp. Sziklai pair, but I don't know this exactly.
If there really pure Class A by the output power devices, where is a heatsink with the appropriate sizes?
Thank you very much for your posted schematics in advance

You could say this is a self induced nightmare as I knew buying the Shanling cd-t80 on ebay from a seller in China would void the warranty. After using it for very few hours the cd stopped spinning. The lens still moves to try to read the disc. After a few seconds it displays the no cd message. So now I have a nice looking, aluminum clad, rather large paperweight for my desk. I was using a Radio Shack step up transformer to power it up. I wonder if that could have caused a problem as the voltage would still be 60cps not the 50cps as it was designed to run on. I was told this wouldn't be a problem. What is a problem are the audio withdrawal symptoms I'm now experiencing now that I don't have the Shanling to listen to anymore. The upgrade in sound the player gave me was amazing. I'm thinking of buying from an authorized local audio dealer the new cd3000 that Shanling just recently introduced. Anyone interested in a big paperweight? Maybe I'll list it on ebay and chalk it up to a lesson learned the hard way.

Despite lacking expertise, someone asked me to see if I could determine why a Rotel RA-1412 is not working. It has dual power supplies and my first thought was to look there. My skills are rudimentary and with some coaching, it appears that both power supplies are OK.

The amplifier's problem is no audio output. The first thing I noticed was two 8 amp rail fuses were missing on the left channel's power supply board. Replacing them cause a DBT to glow brightly. I checked rectifer diodes, stabilizer transistor and output transistors.

Two of the four left side outputs are blown which are 2SD426. The internet searching I did this afternoon identifed two potential replacement candidates. MJ15022 and MJ21194. Limited quantities of both are on hand at a major supplier.

I am poor at reading data sheets.

Both of those tentative replacements claim audio amplifiers as an application. But most if not all their numbers exceed those of a 2SD426.

I understand that within some parameters, more can be inconsequential or perhaps even better. My hope is that someone here can either vouch for an MJ15022 or MJ21194 as being suitable or suggest an altogether different one.

At this time, my intention is replacing all four 2SD426 outputs on the left channel only. Being dual power supplies, my thought was to leave the right channel's functioning 2SD426 outputs in place.

I opened up my very inexpensive dvd player yesterday to try to look for upgrade options. I noticed that the opamp used for the audio output was an NE5532. Could anyone recommend a specific opamp to upgrade to, or is the NE5532 a decent opamp that I shouldn't worry about replacing for now. I noticed someone talking about an OPA2134 as a replacment. Any suggestions would be apprecited.

Thanks

Rob

Hey guys,
Having a problem with a Sony 5-CD changer. When I load a disc, the mechanism grabs it and starts to spin it, but the disc won't read. No track count, total time etc. Pressing play only shows an attempt to read track 1, but then it goes back to showing "0" on the display. The disc spins perpetually, even if I press the stop button. It will only stop and return the disc to the slot when you press eject.
When spinning, it makes a chirpy sound -- like the laser is trying? Not really sure (see video: Shared album - Simon Cohen - Google Photos ).
I've tried cleaning the CD and the lens with isopropyl alcohol -- no difference.

Other things I've tried to diagnose:
- Laser diode appears to work -- I can see a faint purple light when the diode pops up to read the disc
- Tracking servo appears to work -- when I advance the module on the rail manually, and press play, it returns to the closest position to the hub.

Any bright ideas or is this thing toast?
Thanks!

Hi Everyone

I changed the electrolytics in my friend's Pass Volksamp Aleph 30 based on the recos I received in this thread:

Best choice for Aleph 30 re-cap

I'm now testing the amp to confirm everything is operating within spec. Can someone kindly confirm if following measurements are OK?

1) Both + & - power supply measurements show 25.6V DC with 64 mV ripple.

2) DC offset is 73 mV on one channel and 10 mV on the other; I believe these are fine, but is it unusual for the channels to vary that much?

3) I'd like to check the bias, but I'm not sure where the test points are. The amp is physically a little warmer than I'd expect at 56C.

Thanks in advance

I know enough about electronics to be dangerous, and my forte is old tube radios, so trying to figure out the protection system in a modern-ish hi fi amp has me puzzled, especially since Denon doesn't put voltages or useful circuit descriptions in their service manuals. I guess if I was a qualified service technician I would already know, right?



So, what had happened was:
I turned on the amp, and it hung at "1 Front Large". (I only have 2 speakers and was using it in stereo mode). Front controls were non-responsive. I didn't realize that was the protect mode, but...


(If I remember correctly, it had turned on, but I had a phono pre-amp plugged into the front AV inputs I'd forgotten to turn on, and didn't want to frighten the Denon, so I turned it off to turn on the pre-amp, and when I switched it on, that's when it would no longer work.)



I took the thing apart and immediately recognized 2 very swollen 10,000 uF capacitors. Well I know about caps, and I measured them, and they were about 30 or so uF each. Wow, how did I not hear hum as they slowly deteriorated? Anyway, Mouser has some nice Nichicons, so I replaced those, and a handful of other power supply caps for the helluvit, and...


No change. I was thinking maybe it's the microprocessor, because certainly it would tell me if it was in protection, right?


Anyway, after much futzing around, I decided to connect speakers to it, and noticed it only sends output to the Front B speakers. (Nothing on the front works, so no volume, no speaker selection, etc.) I noticed a loud pop, a brief hum, and then nothing. I then noticed the woofer of my cheap test speakers was being pulled way in. DC! Holy crap.


Disconnected the speakers and put some 10 ohm resistors (about 5 watts) so I could poke around. Yep, DC on the collectors of the front Left and Right channels. Also, wide DC swings on the base of both.


I disconnected the pre-amp board, to see if that was the source of this DC voltage into the power amp stage, and that disabled the protect circuit, the base voltage swung above my scope's screen, and before I could comprehend what was happening, I heard my 10 ohm resistors sizzling and burning.


Now they're 20 ohm's each! OK, so we'll put the preamp board back in.


Trouble is, I can't figure out what would affect both channels the same, and whether the bad caps had anything to do with it.


All DC voltages from the power supply seem normal.


The service manual is available from VinylEngine, but I don't have permission to post a link here. I presume Denon's amps of the mid-2000s are similarly designed, and hopefully someone can guide me.


A good tutorial on how these amps work, and a way to figure out which transistors are part of the amplifier, and which ones are part of the protect circuit would be helpful, as would some basic things I could check.


I have a scope, a soldering iron, and an account at Mouser, so that's enough to make me dangerous, I think. I would like to get this thing fixed and off my bench so I can go back to my tube radios and record players.


Thanks.


Dan

FS: 2x completed LM3886DR [SOLD]

Everything is now SOLD

Update Dec 13, 2020: SOLD

Update Nov 22, 2020: chassis is sold, only boards remain

The pictures show a chassis, but that is not included. Only the completed LM3886DR boards and cables are offered. See post #5 below.

For sale is a pair of completed Neurochrome LM3886 Done Right modules.

I built these about two years ago, see here.

I have since pulled that Connex SMPS for use in another project. I have too many amps and am trying to downsize and declutter!

Asking $50 (USD) for local pickup, or $65 shipped in the USA (USPS flat rate priority box). Domestic only at this time (sorry, can't do international right now).

Thanks for looking!

There are several quantitative measurements for low voltage audio power supplies which are easy to implement -- PSRR, Output Impedance (and transient response), Noise, etc. In the digital audio realm, I would guess that reverse PSRR could also be important. More difficult to measure are regulator error amplifier issues.

Which do you consider to be the most important criteria for vacuum tube power supplies?

PSRR, or "Line Rejection"?
Output Impedance (or transient response)
Noise

cosmetically nice, no lock assemblies only suspension, no cover
1019 has good quiet motor, needs lube job. I cannot change speed, runout return working has Shure M44E cart and stylus. $125 + shipping

Does anyone know where I can get a manual for this meter? I've had it for years and have lost mine. I am not having luck finding one online. I sent a message through the mastech website and got an error message in Chinese...