Hello to all.

I have a set of Wharfedale Pro LX-12 which I love.

Hooked them up recently again and noticed that when a song is playing and the bass hits the top speaker (only on one in this case the left) cuts in and out with a little crackling while the right one plays perfectly. Lower the volume and it seems to come back and stay steady.

Bottom end plays perfectly. The just the top on one speaker.

Seems like something is loose. checked the wires inside and all connection to the speakers seems sound.

Anything else I should check that may be a known culprit to my issues with the speaker? 😕

Thank you in advance and hope everyone stays safe.

Hello everyone,

I would like to put out a few questions regarding the scaling of horns / waveguides. I assume it would be nice and interesting to hear the comments and opinions of the learned forum members on this topic. The main questions would be:

1) Are horns scalable? If yes, then which types are and to what extent?
2) Is it possible to scale a horn along certain directions only? For example, the width and height change with depth remaining the same.
3) How are the characteristics such as cutoff frequency, directivity, frequency response etc. of a scaled horn related to those of the original?
4) What would be the advantages / disadvantages, if any, of horn scaling? Is it worthwhile scaling an existing design ?

I am quite sure that at least some of you have thought about / tried similar things. It would be nice to know the results from such attempts in particular. Thanks.

Hello
I'm thinking to build a NOS DAC and I found a bare PCB on Ebay, at Jim's Audio store.
TDA1543 x4 CS8412/14 NOS DAC PCB w/ vibration proof clock PCB highly musical !! | eBay

This PCB has an SPDIF input and an analog audio output. I will also need a digital input selector (1 optical + 1 coax) to connect my CD player and PC on.

I have no experience on DAC's, so I would appreciate your opinions about this PCB. I'm looking for a budget project, a kind of audiophile, because the most of the time I'm listening to classical and jazz music.

Do you think that it's worth and meets my demands? Does anyone try it?
Thank you in advance.

used in 5V suply of usb/i2s converter. dont use this dac anymore so its a waste to let it sit here. 80eur. its already desoldered and legs straightened.

have some other bg left, but not much ( 25v 1000std , 50v 220uf std, 6.3v hq nx)

Wanted:

A copy of the service manual for the Iwatsu TS-8123 Storagescope.

Does anyone here have a copy?

Or own one of these scopes?

Hello, I have different PC now (Dell optiplex 990) and struggle with the SPDIF output.
Most motherboards have the two pin SPDIF out straight out the motheboard, but mine doesnt have this connection.
Does exist some board or something like that which will make SPDIF lets say out of PCI?
Because I dont want to use USB/SPDIF converter.
Thank you very much for help. Best regards, Michal

looking for waveguides for Seas T35C002 domes. Thx

I decided to do this so that I can have PCB that will drive various OPS for experimentation. The 4 transistors were each under $1 bought in quantity. Many days of curve tracing to create matched pairs.

All of the resistors, terminal blocks and PCB together probably cost more than the semiconductors.

If I burn up this board while experimenting, I will not be throwing away a bunch of money. On the other hand, making such an experimenter board from PL JFETs and MOSFETs would be relatively expensive.

+ / - 35V rails. 3mV DC output offset. 2.2mA bias front end. 10mA bias second stage.

Gain slightly under 10x

Output impedance 55-ish ohms.

Better than 60v p-p before clipping.

Bandwidth is insane. -3dB 14.3 MHz with a peak 10-ish MHz. Phase is quite wonky out in the MHz space.

Good enough to use as a driver for various OPS experiments.

Front end devices are 2SA970BL/2SC2240BL
Output devices are KSA1381E/KSC3503E

Feedback resistors ended being 1k after some experimentation. The schematic will be changed to reflect 1k feedback resistors.

Has anyone tried down firing ports on bookshelf speakers?

It would seem to eliminate the problems with rear ports being too close to the wall and if the tube is long enough, it would be up behind the tweeter.

In these Wharfedale Diamond 220 speakers, I am wondering about the size of the gap the bass is coming out of. Isn't the small size going to provide resistance and therefore the port is not a "normal" port size/length?



If I you were to use a 2" diameter downfiring port, how much space would there need to be between the port the the bottom base/platform?

Guys


Can anyone recomend any Youtube video's too watch as a newbie?


I'm building my first class D

I am wondering, in the pursuit of low noise, would it be possible to use the leakage current of something like a 1n4148 to bias up the grid leak? and eould this offer noise benefits over-say, a run of the mill 1/4W metal film?

Rohde & Schwarz UPD: #1 Troubleshoot then Restore to Glory




I just opened up my UPD and thought I would get it up and running. I don't know whether to keep this in the UPD thread or start a new one.

Anyone that has completed the Cap replacement on which are the most likely
candidates?

Mother Board?
Power Supply board?
I need to post this so I can find it and read it again while posting my other questions.

ELKO Caps, Brand is elko yes?
It's hard to see in there, and dusty.
I'll blow it out soon.

Yes, I have the top and bottom off the unit.
There is additional shielding (sheet metal) that
needs to be removed.

Are we talking the PSU board or Power Supply?
Power supply being on the BIG heat sink with the
two shielded transformers. I haven't testing anything,
just trying to only remove the screws and parts needed
then ID the proper parts for replacing.

Goal is to get it working before doing hard drive and
DOS upgrades.

I'll post what pics I have. My UPD is optioned out except for
the AES-EBU Spidf and the 2nd Digital plug in with COM 2
and word port.

Any one who's refurbed this have a BOM or Digikey order etc?

Does anyone know of a good repairer for oscilloscopes and other such equipment in the UK?

I'm happy to consider both professionals and amateur enthusiasts/hobbyists.

Hi everyone,

A few years ago, I built a Madisound FR kit BK-12m Folded Horn with some generic hand me downs. I really like their sound and immediacy, though I realize the frequency response may be non ideal. There is something I seem to like about sound without crossovers between an amplifier and a driver.

Sources are mostly over the air antenna, discs and the usual streaming platforms. A Pioneer SC97 does the processing and amplification. I generally use only LR for music. Room is a rectangle 15ftx30ft, with the speakers in a listening area that is a 15ftx15ft square, using 3 of the walled sides of the rectangle.

Fast forwarding to now, I have a pair of Polk lsi15 for left and right. Since opinions seem varied on the matching lsic / lsim 706c, and they are difficult to find or cost most than what I paid for my used pair of lsi15, I wanted to check if there is a full range driver for center channel that folks recommend. I could do a flatpack kit or or open baffle.

Total cost ~ $200.

Other options are to use the center from my previous setup - a Pioneer SP-C21. I am also curious about coaxials drivers like KEF.

With the equalization of the pioneer receiver, which of these will provide the best dialog ?

I'll admit that the most improvement in dialog was by a heavy curtain to cover a glass window directly behind the listening position.

Thanks in advance for any help and suggestions.

Looking for an Audio Research CDT dead or alive. preferably one with a bad laser or other problems. will consider a fully working unit if the price is right.


ZC

Two power amps I used in a DIY subwoofer setup for a while. Purchased both new from Parts Express a couple years ago and both are still in great shape.

Crown XLS 1002 - $125

QSC GX3 - $150

Hi,
Does anyone know what kind of capacitors used in BAT VK-40 "6-pack" capacitor upgrade? Is it possible to purchase the correct capacitors and do it myself? Thanks for your help.

I've gone through the kaleidoscope of in-series inrush and current management ideas, and pretty much all end up either (a) sucking power, (b) having a inrush spike on bypass.

I'm both (a) running 600mA class A and (b) charging 6mF of caps to get a smooth 1Vpp ripple. I'd like to have both (ie full load and inrush) so that the voltage regulator and the capacitor are started together to minimise the time to start. (the cap also acts as a low pass filter for the switching)

IXYS did a 'reference' design using a Zilog CPU to manage inrush (Digital Inrush Controller if you want to google) by essentially having the Zilog produce the PWM required to switch to manage the current through the system.

A faster option perhaps would be using a CPLD such as a MACH04 - this even exists as a breakout-style board. The CLPD can generate fast PWM based on an input mapping and trigger signal. The internal clock is 16MHz and so would be possible to create a 100KHz or better PWM.

External zero crossing, triac and mosfets could be used to handle the AC 240V power with high speed galvanic (ie 50Mbps+ capable) could then be used to isolate AC from low level voltages.

My university degree had realtime and embedded as part of this so I understand some of the gotchas in timing, concurrency etc with CPUs hence the interest in CPLD being more realtime focused with minimal boot time, fast response and singular purpose.

Just wondered if anyone has looked into this already?

Hey there folks. Over the last couple of years I've played around with a lot of configurations of Sigfried Linkwitz's systems and now that I've settled on one, I'm looking to let go of excess equipment gear, some slightly used, some new in box. Most items are located at my new home near Vancouver, BC Canada, except for the L26 Sub-woofers which are available in Nevada City, California.

Photo of all items here: Gear for Sale - Google Photos

Here's what's on offer:

1) Peerless SLS 830668 10" Woofer: Peerless SLS 830668 10" Woofer - Coated Paper Cone
-3 pairs available
-$80 per pair, new, never-opened, plus shipping at cost or pickup on Salt Spring Island, BC Canada

2) Seas L26RO4Y 10" Subwoofer : Seas L26RO4Y 10" Subwoofer - 4 Layer VC - (D1004-04)
-currently on backorder at Madisound, so you could save some dough and get them sooner!
-2 pairs available
-$480 per pair, new, never-opened, plus shipping at cost or pickup in Nevada City, CA
-shipping via UPS Ground most places in US seems to be around $30 per set

3) Seas Prestige FU10RB H1600-04 4" Full Range : Seas Prestige FU10RB H1600-04 4" Full Range
-3 pairs available
-$105 per pair, plus shipping at cost or pickup on Salt Spring Island, BC Canada

4) Hypex FA122 Fusionamp (125W+125W) : Hypex FusionAmp FA122
-1 pair available
-$650 for the pair, new, never-opened, plus shipping at cost or pickup on Salt Spring Island, BC Canada
-will throw in a remote and remote module for full asking price ($40 new)

5) Hypex FA123 Fusionamp (125W+125W+100W): https://www.madisoundspeakerstore.com/speaker-amps/hypex-fusionamp-fa123/ Hypex-FA123
-1 pair available
-$700 for the pair, lightly used, plus shipping at cost or pickup on Salt Spring Island, BC Canada
-will throw in a remote and remote module for full asking price ($40 new)

6) miniDSP 4x10 HD : https://www.parts-express.com/minidsp-4x10-hd-2-analog-in-8-analog-out-2-digital-in-out-dsp--230-338
-1 available, includes remote (usually sold separately)
-$440, lightly used, plus shipping at cost or pickup on Salt Spring Island, BC Canada
-original packaging, comes with remote, power supply, mounting brackets, optical and USB cables


Feel free to direct message me with any questions, or reply on this thread if the answer might be useful to others. I will indicate sold items as they are purchased.

Thanks for looking!

-Brent

I have a number of HV (100V-600V) film caps that I've removed from old equipment. I set up a crude leakage tester by putting a microammeter in series with an adjustable DC power supply. For each cap, I ran it up to the rated voltage. They fell into roughly three groups: First, some showed leakage right at the resolution limit of my meter, showing 0.00-0.02uA. Second, some showed leakage around 0.2-0.3uA. And third, some showed leakage around 1uA.

I understand that ideally, a capacitor should block DC perfectly, with no leakage. But these leakage amounts seem so small that these should work fine in a lot of positions in most circuits (say, a tone stack with no DC, or a cathode bypass cap), assuming that their capacitance value is still in spec. So what would you consider the upper limit for leakage current in a film cap?

I have done a special deal on PCBCAD51 for DIYAUDIO, members only.
10% off normal price.

http://murtonpikesystems.co.uk.servepreview.net/pcbcad51download450.html

Hi

I am trying to build my first WAW with passive crossover. The woofer will be Peerless 830869 which will be housed in a MLTL cab. The full range will be MA Alpair 10p and will be housed in mid-tunnel. Desired crossover point is around 400 Hz. Baffle will be 9.8 inches wide hence baffle-step will be around 465 hz.

I am attaching the dxo file along with some pictures. I used Xsim and Jeff Bagby's response modeller for my design. Please have a look and help me to make it better. Thanks in advance.

Hello,

I'm looking for an online electronics tutor to help me to reach a point where I can design my own audio circuits. You don't have to be a qualified electronics teacher but someone with good knowledge, maths, and enthusiasm.

Since 2012 I have been experimenting with building audio gear kits, upgrading/modifying recording consoles, in 2017 I landed a job as a service tech at my local hifi shop where I now manage my own service department repairing all sorts of audio equipment, mainly hifi but also pro audio.
In 2017 I also did a year of electronics to consolidate all the bits of knowledge I learned over the years, however since then I have been pretty busy with a young family, and due to lack of practice, I forgot a lot of stuff, especially when comes to maths.

I have a lot of good resources at hand in terms of books, e.g Art of Electronics, Designing Power Amplifiers (Bob Cordell), Small Signal Audio Design (Douglas Self),

I'm familiar with simple BJT/JFET DC, AC circuit analysis but I'm not sure how do I go about scaling this up to more complex topologies, multistage amplifiers etc.

I have a special interest in distortion and how it affects the perception of sound, especially when comes to power amplifiers.

Ideally, I would like to establish a long-term relationship and I would be looking for, let's say, 3 email exchanges a month and one zoom/skype call, where you can give me a list of study topics, math exercises etc.
My aim is to develop an understanding of the design process rather than completing any specific project.

If you feel that you could/want to help me then feel free to send me a message.

My audio related social media:
Yestersound
Loudandclearworkshop

All the best,
Hubert

I have recently acquired a near mint Luxman R-3055. Looking to restore back to new or better performance. It belonged to an older fellow and it hasn’t been powered up in years. Was in the original box, packaging and manuals. If you blinked it appears new. It was so clean there was no dust inside. One capacitor @c169 had some leakage which could be glue as it tests okay. I have a nichicon FG on the way to replace it.

So here is the question, what should I replace to make it good for the long run?

I have sourced all 75 electrolytic capacitors and have found elna silmic II, nichicon FG or better and mundorf for the two large power filter caps.

Should I go for it or what should be done. I have no reason to believe the output transistors, power transformer, diodes or opamps aren’t in good condition. I did find a service sticker from 1987.

There is zero indication from visual inspection that any work has been done. It’s clean and totally original. Except for the goo out of C169 it’s pristine.

Some of the capacitors were marked? Does that mean anything.

I've had the 2145, no lift 1-4khz, nice boost in highs, just needs bass boost to sound balanced.

But the fa22 looks nice too, needing the passive eq ckt though. And no phase plug, eventhough the cylinder in the 2145 seems too short.


What do you think ?

Brand new (stunning!) painted top with expanded metal, for Eico 2080 integrated amplifier. Also have brand new bottom panels.

$39 each. far below cost.

Hi all,


Currently I am making a bluetooth speaker out of a 70's speaker to get a bit of a retro look.



I connected a 12V battery to a step down converter parallel to an amplifier board. The step down converter is to power a bluetooth audio receiver.



When I checked yesterday, I powered the bluetooth audio receiver to a different power supply for testing if the Amp worked and I got nice sound out of it. However, today I connected the bluetooth receiver to the step down converter and turned it on and didn't work. The bluetooth gets power and I can connect to it with my phone and play music, however no sound comes out.



I unplugged the bluetooth and got it on the independent power supply again, to see if something happens there, but also again, no sound comming out.
I did some tests and if I turn on the amplifier, I get a sound for about 1 second before it turns off again, this is with just the 12V battery powering the amplifier and nothing else.



Does anybody know what can be the cause of this? I tried checking the signal with a multimeter on AC onto the speakers directly and I do get around 3mA of signal, but nothing happens. Can this be a broken amplifier board or broken speakers?



Things I checked.
I have 12V on the amplifier board.

There is a direct connection from the sound input (at jack level) to the sound output (at the speaker)

There is a connection between the ground of the speaker and the ground at the amplifier board.



Any help would be appreciated

I really like stabilised B+ for everything i build.


Ive allready done maida-style regulators with a tube as a pass element, and i have used current source loaded EF184's for control of the tube.. Both gave excelent results.



I was looking at the denoizer for the 317 found in this thread https://www.diyaudio.com/forums/pow...canceller-retrofit-upgrade-317-based-reg.html


and i figured, what if i combine all these ideas into one?


I figured i could CCS load the pentode with the adjust pin of the 317 and run the 317 as cascode with the pass tube.



Im curious as to what people think of this..

Crutchfield has a tool which allows one to listen to various speakers, through your "defined" headphones. Video explains how:

Crutchfield - Seriously Into Audio Since 1974

Of course, limited to their house brand and other brands they carry such as KEF, JBL, Revel, Jamo etc.

hi i have a dcm sw10 but what id like to know is it a good subwoofer or is it time to upgrade

Can such a rectifier circuit be built? How is the result?

The 300B tube amplifiers that I want only have a single 8 ohm tap. I find it to be quite a chore trying to find a high sensitivity 8-ohm speaker.

So far I have looked at Klipschorns (used), pi speakers kits, and diysoundgroup Titan 615 (no longer sold?)

Are there any other designs I am missing with at least 95db sensitivity at 8 ohms?

I have some clear sounding speakers these days, something I never had before.

..and I've become convinced that software EQ is bad..

When I play music straight through the amp (no software EQ) it sounds great

With EQ enabled, the tone adjustments are obvious, but in general; specific instruments are less discernable, sounds are 'muddied' or 'blended' in a way.

Is this technically valid ?
Is there a word for this ?

I'm familiar with the Fourier transform. In particular the way the phase and frequency information are separated, then recombined after the frequency amplitudes has been adjusted.

Surely this can't be ideal. It's not the way frequency and phase interact and attenuate in reality..

I want to blend my Eclipse TD508Mk3 single 8cm (3") speakers with a small, fast sub. (not yet selected). In their enclosures they are 10db down at 52Hz.
I would like to use an active high-pass filter (like a MiniDSP) to reduce cone excursion and bass distortion without negating the impulse-response/time-domain advantages the 508's are known for. I'm thinking 24 or 48db slopes around 80-120Hz should accomplish this and hoping that passing at this low a frequency won't hurt the sound. Is finding the best crossover setting something better to do by ear or crunching the numbers first then verifying by listening? Is spending more for a better crossover like a Pass worth it or is any crossover likely to do more harm than good?
I appreciate your thoughts!

Will we have 3D printed fungus sound absorbers next? Fraunhoffer think so.
Fungus as a sound absorber

Hi there good people, quick hornresp question.

I'm using hornresp to design a tapped tapered transmission line. I have found a configuration that looks very promising, but cant seem to get the filling to stick.

it works fine in the loudspeaker wizard, and the spl graph looks great however clicking save on the wizard, and then calculating, it shows the old spl values without the effects of filling.

Am I missing something?

https://www.americanradiohistory.com/Archive-High-Fidelity/50s/High-Fidelity-1951-Summer.pdf

Page 10
I find interesting how well people like Paul K loved the BROOK amplifiers.
He goes on and on about the the BROOK especially the 12A

Now you have to read carefully but below is a snippet from the article above.

Paul W Klipsch writes:

" However, for the benefit of those readers who still insist on knowing the author's personal preference for an amplifier to use with the Klipschorn, here is the answer: the Brook. Not that this is a better amplifier than the others mentioned by name, but for the following reasons: 1) it is a good, low- distortion wide -range amplifier, z) it has a rather definite upper power limit which prevents damage to the delicate high- frequency speaker driver used in current Klipschorn systems, 3) it has a very highly refined preamplifier with proper equalization provisions, and 4) it is amenable to a very slight revision for full bass extension applicable to Klipschorn (referred to as K -1 re- equalization). The specific designation of this amplifier is the Brook 12A3 -K -1 and is rated at 10 watts output. Significant is the fact that it has been found to deliver 9.5 watts of clean output at 3o cycles. This is more than adequate power for driving high efficiency, horn -type corner speakers. Probably, for home use, peak amplifier output of 1 watt would suffice to feed a Klipschorn. ""

I've seen this modification mentioned before.

Joe Roberts in Sound Practices wrote a little blurb about it. Read it in the corner of the schematic below.
Joe is referencing the Paul WK article.

The 12A could be slightly modified to be a 12A3-K1 this mod was specifically for K horns.

The picture below is from the magazine Sound Practices
They mention the K1 mod in the corner.



So here is my question
Has anyone here ever seen or read about this K1 mod for BROOK 12A amplifiers?
I have an idea of what could easily have been done.
But I'm curious if anyone has seen one in the wild???

What directivity can 3 sources produce?

Hi,

A single source gives 360 degrees radiation pattern.

Two sources, in a cardioid give radiation in one direction only. The total directivity angle is 180 degrees.

So, adding more sources produce narrow directivity.

If 3 sources are used, how narrow does the directivity get and how should the drivers be positioned/delayed/tracked(and attenuated, if needed), assuming sources are omni on their own?

I would like to simulate.

Thanks and Regards,
WA

I realize this may be a simplified schematic but looking at this circuit I have a question about current flow. If I had the 10v supply turned on without turning on the + and - 15v supply would there be any chance of damaging the jfets and would there be any current flow ?

I am in the process of building a Tubelab SSE and wanted to see if anyone has any output transformers and power transformers they wanted to sell before I pull the trigger on new ones.
I am located in Vancouver Canada so will be after 120v.
Please let me know what you have available?

Regards,

Bassy

Hi, I'm looking for board layout for the LM1876 on a single supply for 48-52v. I've been tasked at work to design an amp for 2 x 15 watt horn speakers to be poe powered the board should preferably be single sided.

Hi,

I have recently purchased an ARC SP8 Rev 3 from the '83 in working condition that I Would like to upgrade with some modern parts and ideas. I have already recapped the preamp PSU, upgraded 2 OPAMPS, changed the rectifier diodes and put new valves on it, I first Would like to concentrate on the PSU. Voltage references based on noisy zener diodes is my next step. I Would appreciate it very much to have some feedback on several points I Would like to share with you.

My strategy is to replace 2 zeners and a LM329 with the attached circuit (vRef):

1. 2 B+ voltages (phono and line) are regulated using 1 12BH7A and 1 ECC83 (this one working at 400 V, far over specs ?!) together with a couple of tl2071 OPAMPS. Both cathodes of the ECC83 are paralleled and biassed with a noisy 10V ZENER. I Would like to replace the ZENER with the low noise referred equivalent. To provide enough current to the voltage reference I plan to get additional 6mA from a 24v available regulator.

2. An additional 24V ZENER is used to power a tl071 OPAMP attached to the base of a darlington set acting as a HT voltage regulator. I believe the circuit proposed above can provide lower noise at the OPAMP power supply.

3. A LM329 is also used as a fixed reference of an inverting tl071 input. It is a nice device but also a bit noisy.

I Would appreciate your comments / suggestions.

Kind regards

Toni
Barcelona

I have been tasked with the repair of one of these lummoxes.
Principal symptom - gradual loss of positive going swing on L channel as
it heated up. Found that some of swing returned if I cooled the + side predriver
(MPSA92) so I replaced it, and the adjacent current sources (BC556x2) This
helped a lot but when I gave L and R a good roasting, found the same fault
appearing on the R channel. Transistor replacement did not help. I'm beginning
to suspect some deeper systematic issue. Audiolab could(would?) not help and
referred me to a service dept in Germany (I'm in New Zealand!). Does anyone
know of any "known issues" with these amps?.
Cheers, M.

iam sure this question has come up before or is even unanswerable but i will ask regardless.

Iam planning to build a kt88 amp, i found the circuit for the modified williamson circuit on the Plitron website. A friend mentioned to me that fixed bias was for guitar amps and i should convert to auto bias. Should i keep the fixed bias or convert it back to the williamson? Your thoughts, opinions and past experiance would be greatly appreicated.

Hello,

I have a Lab 15 just waiting to be put into use in my HT. I have played around with designing an enclosure for it. But until now I didn't have an amp. Now I have a TA3020 amp and SMPS800RE on their way to me. This should be plenty of power for the sub.

Design goals:
For use in a home theater, so the lower this can go the better.
I am looking to keep this around 5 cf. (6 cf max.)

I am looking a making a TL with a response down to 20 Hz. Total size is ~5 cf.
A br including the port models about the same size and fr.

I am looking for anyone that has experience with TL or tapped horns for home theater. In searching the forum I found a some people using these for pro audio use. But not much info on HT.

Later tonight I will try to post measured T/S and box sims.

Hi All, this is my first post. I am attempting to design a speaker and I have some questions. I have searched the Internet and have not been able to find adequate answers.

The first question is in regards to the voice coil. In order for me to get a comparable Mms to stock speakers I need to use a thin wire (36 awg) to obtain a value of 6 ohms Re. This wire gauge is rated for only 0.21 amps, yet the stock speakers are rated at rms power values reflecting currents ten times this value. Am I correct in assuming that because a music signal is so dynamic one does not consider the rated rms current of the wire? If this is the case just how does one determine if the wire gauge is adequate for the application?

My second question is in regards to the suspension of the diaphragm assembly. Other than centring the voice coil in the gap, are the any intrinsic benefits to a spider? Are there alternatives to a spider?

Lastly, the only information I have found technical enough to design from are the two papers “Green Speaker Design” published by KLIPPEL GmbH. Are there any other good design guides out there?

Thanks

Selling a pair of Dynaudio D-76AF dome midranges.

They are new - NOS, never used. In original boxes.

They were part of a Dynaudio Xennon-3 speaker kit project that was started, but never finished. A friend of friend purchased Dynaudio raw drivers and Xennon cabinets to build these and never finished as he passed away.

This pair was never mounted and originally purchased as spares to another set of D76 that were mounted in cabinets.

I measured DC resistance of each with Fluke DVM. Each measure 5.2 ohms. I also briefly applied low level music to verify proper sound and no distortion. Both sounded fine.

Just as an FYI, I also have the 24W100 woofers and D-28 AF tweeters. These are new - NOS in orig boxes as well.

Asking $425 OBO. Selling as a pair. Prefer to sell here instead of that auction site.

Will post pictures in the next day or so. Or message me and I can email some..

Willing to sell the cabinets as well, but I won't ship those. Need to pick up in the mid-atlantic area (Baltimore - Wash-DC). Willing to drive part way if you want to buy the cabinets.

thanks.

Hello. There is a difference from qtc cabinet point and smoothing impedance peak between this two situations please : 1. Enclosure uniform full filled with fluffy stuffing material. 2. Half of enclosure filled with same quantity of stuffing material. I strictly ask for effect into qtc of the cabinet please, thanks.

the other day while searching for digital chips found those in evenlope.

~150psc qty, 5eur/eah or trade to 570ohm values(to 144psc or at least 8psc)

Wondering if this was done by the factory or is a manufacturer defect?

The pot is for the crossover frequency

Hello
At present, I am restoring Lowrey's Orchestration Plus Project, and I am looking for Second Hand Lowrey MX-1 Organ Parts.
I am particularly interested in the CPU Board, the Memory Board, the Parallel Interface Board, and the Orchestration Plus Boards.
If Anyone can help, I am quite willing to send them the proper Antistatic Packing Materials to safeguard the assemblies during shipping/transport.
Thanks, and Kindest Regards;
Telnet100

hi,

have anyone the schematic from this amp?

yamamoto a-08

thanks
sonix

A new run of these boards is now available! Please see the following thread for details:

http://www.diyaudio.com/forums/soli...ble-here-bal-bal-se-se-lpuhp.html#post3516741


Hi Guys,

After having messed around for quite a while with several variations of Nelson's D1 with various modern DACs, I've finally come up with one that I think is worthy of being posted for everyone to use.

I've combined the excellent transconductance of a power mosfet, with the low distortion of a JFET buffer to get to the circuit below. It's basically a low impedance D1, with a different mosfet, and a B1 buffer in place of the old mosfet based buffer. You could probably call it a D1B1.

The circuit below provides about 2 VRMS at 0dBFS output when used with a ES9006 run in stereo mode. Performance is superb, and all the measurements are attached. THD+N is 0.000515% (-105.5dB) at 1kHz -8dBFS. This is without matched fets, and a seriously kludged home-made PCB, which means it can be made better with a decent implementation. Even the way it is, I think it sounds excellent.

This circuit could easily be adapted to work with any DAC, and provide almost any gain needed. The gain was set so low to minimize voltage swing at the DAC output.

The source of the mosfet sits at 1.65V which is what the DAC wants to see, and the drain sits at a little over 9 volts which allows direct coupling of the B1 input to the drain. Gain can easily be increased by increasing the value of R1, R2, R3, and R4 while maintaining the same ratio.

I'll be starting a PCB layout with this circuit and the ES9018 DAC which should provide some pretty incredible performance.

Anyone feel like helping with the digital side of the DAC?

Cheers,
Owen

We know residual B+ hum tends to cancel in PP stages, the same going for the heater supplies - higher PSRR for PP. Can we get away with AC then? What about IMD?

i have one packed with 50 NAIS relays - DS-2E-M-DC12V-1C / AG 205344B99 (silver (Ag) with gold plating) for sale. High sensitivity: 200mW input power Type DIP-1C can be used with a 14-pin IC socket. Only complete packed is for sales. Relays were still made in Japan. Asking 100€ + Shipping + PayPal + 4% fee. I still have 2 packs more of these Nais relays, all of which were bought from Arrow / Spoerle Electronic in Germany. Shipping only with registered mail by DHL from Germany. Shipping prices are different depends on the country.

I'm interested in putting together a powerdrive circuit for an 845 amp that I've got built. I'd like to replace the fairly tame class A1 capable driver stage that I'm currently using.

I've discovered though, a lack of 2SK2700 mosfets.. I could order on ebay, but I kind of hate ordering stuff from China.

Are there any other compatible mosfets out there that would be suitable for the powerdrive as implemented on this page 845 SE | Tubelab ?

I've been searching online to find equivalent mosfets, and I'm coming up with stuff that is severely lacking in many of the specs I've found for the 2SK2700.

One suggestion was the STP3NK90ZFP.. But it's got a much lower power dissipation rating, and much higher drain-source resistance..
In trying to match up specs on Mouser's website, I've found parts like the Cree C3M0065090D http://mouser.com/ProductDetail/Cre...fT7raD8v7sJKQWPXTvN7IFrDEDiDpnHams%2bSBZJ8w==, but rds-on is higher 90mOhm, power dissipation is lower @ 125W, but continuous drain current is MUCH higher though 36A..

Or the Fairchild FQA11N90_F109 http://mouser.com/ProductDetail/Fai...=sGAEpiMZZMshyDBzk1/Wi2h9uecfVnmSNyG138FKIdM=.. Which looks somewhat similar, although higher rds-on..

What are the important specs with regard to the powerdrive circuit as implemented in the 845SE tubelab page.

Any suggestions?

Hi guys,

I'm writing here hoping that someone found the same behavior or can give me any advice to repair a Crown I-tech 6000 amplifier.

The amplifier came to me not turning on at all. Power diode D1005 from BCA output stage was shorted. I replaced the bad one and the one that is in parallel. After some preliminary tests everything looked OK with one exception. The repaired channel (CH1) is overheating and in ~ 2 minutes it reach over-temperature and is shut down. I must stress out that it passes clean audio until it is cut down by overtemp protection. Cooling system is ok and is throttled progressively to max speed.

First thing to do was to adjust overlap/underlap according to service manual. No improvement. After that I swapped the front-end PCBs between channels and the problem moved on CH2. I made a lot of measurements with oscilloscope and compared with the working channel but nothing came out. Feedback, differential drive to gate drive boards, VP/VN voltage was measured and everything looks ok. Also each component ohmic resistance from bad front-end was compared to the same component on working front-end and nothing. I have no idea what can cause excessive heat dissipation in this BCA topology.

Now I'm out of ideas and ask for diyaudio community help.

If someone needs the full service manual please write me a private message.

Does anyone have a FR plot of the 3" Vifa Scan Speak dome with an appropriately sized rear chamber on it? All of the published graphs are without a chamber and that doesn't show the full low end rolloff potential to incorporate into the xover design.

I'm planning a 4 way mid field monitor build with these drivers.

Woofer - SB 34NRXL75 up to 200 Hz
Low mid - B&C 8NDL51 200 to 900 Hz
Midrange - Vifa D75MX41 900 to 3500 Hz
Tweeter - Seas T35C002 3500 Hz and up

The crossover planned is fully passive 2nd order LR slopes (if i can get away with it) and the option of biamping LF section separately from the low mid with either passive or active filtering. I could have built a 3 way with a better mid driver, but I need 110dB capability (mostly for tracking drums) with low total HD across the whole bandwidth and the D75 mid dome won't cope with sub 900 Hz xover and still play loud enough due to limited xmax.

I didn't have access to the Volt 752 dome or better yet the big ATC, both of which would have been my first and second choices. I've heard the 3 inch Vifa SS dome in other designs and like it alot if run above 900 - 1000 Hz. It can play very loud and clean as long as its not pushed too low. I have 2 pairs of them in case I decide to do a 2.5 way MTM to get more low end and help with BSC while trying to keep up with the midbass section. I'm aiming for -6 dB power response from 100 Hz - 10 kHz which sounds the most natural to my ears.

The tweeter choice was after hearing the shear dynamic capability and low HD of the large T35 Seas dome, even without a waveguide (which I still may use). It has ample HF extension on its own, especially with some passive filtering EQ tricks and it will live a long life crossed over at 3.5k 2nd order LR. I really love the way these large domes sound in general. Im not a fan of most cone mid drivers mainly due to HF cone break up plus the way they beam at higher frequencies. That doesn't mix well with the driver it needs to mate up with and hurts power response as well. I was tempted by the big Beyma TPL150, but it sounds too aggressive in the lower mids to my ears, plus the limited vertical dispersion kills it for me.

Im open to suggestions. If anyone has some constructive input I'd really welcome it.

Guys,

I am trying to diagnose a loudspeaker that I bought as a kit. I believe there may be an issue with the engineering of the bass unit. The woofer has been fitted in a more or less standard cabinet (for that supplier) and does not sound right to me.

I have spent vast amounts of time reading up. I have found many references to the work of Martin King, George Ausperger, Bob Brines etc. Unfortunately the alignment tables, worksheets etc. mentioned can be found nowhere, and now I am stuck.

I hope that someone could point me in the right direction. If the documents are free for sharing, I hope that someone is willing to do so.

I am a practical guy looking for a solution. I am willing to share the details of the design (drawing of box) and woofer. Maybe someone is willing to help?

I have measured the line length, SI and SO and the terminus size.

Hi, Gang,

Mine is shot, reasonable replacements are pretty thin on the ground - does anyone have a working PA 211 for a PAS-3X for sale?

Thanks,
Frank

Putting together a 4 way design using SB acoustics SB34NRX75-6 12" woofers, thinking of using an SB17NRXC35-8-UC uncoated mid woofer AND a Silver Flute W17RC38-08 to handle the upper bass region.
A pair of Morel CAM 558 2-1/8" Soft Dome Midranges and a pair of Dayton RS28F-4 1-1/8" Silk Dome Tweeters.

Have the woofers in cabinets, plan on ordering mid woofers next week.
My thinking on using two different mid woofers is to smooth out any resonances or nuances.
Any thoughts?

And so it begins...(?)

For quite a while I've been reading through the various threads on the DIY line arrays based around the the original IDS-25s (Wesayso, Fluid, AttilaM, et. al.) . After giving it a lot of thought and working through some numbers I decided there was no more standing around on the sidelines - time to get in the game. 😀

As a bit of a Xmas present to myself I just put in my order with Madisound for a whole bunch of TC9FD18's. Price was $7.85 USD each for quantity>=45 with free shipping. As much as I was hesitant about line arrays due to the total driver cost, when I started putting together the full build sheet I came to realize that the other expenses, coupled with time and effort needed made the issue of driver cost relatively minor (or at least more palatable) in the grand scheme of things.

Got a cabinet design laid out on paper. The plan is to keep it relatively straightforward - a dampened plywood box, plenty of bracing, front-mounted drivers on a single layer baffle. About 2.2L per driver stuffed.

We'll see if this plan survives first contact with the table saw. 🙂

I'll try and keep this thread updated as things progress At this point I don't expect much construction to happen until the week before New Years.

-b

Interested in design guidelines for minimizing H3 in LTP drivers. I know there has been a bit of work with tuning the k resistor in a simple grounded cathode stage, but I haven't seen any relating to LTP stages.

Has anyone done and published any such work? Tube selection, circuit design, anything?

Going to be building a set of smt 212's to try out. Im using the b&c 12pe32 drivers in the cabinet but im still struggling to find a compression driver that will match well. And size? 1", 1.4", or 2"
Anyone have any reccomendations?

Hello all-

I'm hoping to find a PCXO solution that has the following features-

-Presets changeable via key command (I'd like to use an Elgato Stream deck)

-mutes outputs during preset change (presets will get changed with music playing)

-ASIO support or other low latency audio driver option. I think WASAPI should work (I'm not familiar with it), but ideally I'm trying to get my full latency on an IIR preset down to sub 1ms.

A little background, this is for a recording studio with multiple users. I can get a KVM switch for troubleshooting, but ideally the PCXO will be run with no mouse or keyboard. Being able to use the Stream Deck (or similar) then is important because it creates a simple interface that anyone can understand, and limits access to someone messing with the routing etc.

Worse case I can use a daw with assignable midi mapping, like Studio One. But it seems that a dedicated solution might be less messy.

Thanks!

For quite a while my speaker design was settled. It's three way with a sub; main speakers being SEAS L18, Morel EM1308 and Morel MDT30. I won't bore you with the xover details but the sound was seamless from top to bottom, plenty of depth and ambience and a wonderfully natural timbre - especially piano and acoustic guitar. Jazz made you feel like the performers were in the room with you. Very inviting and enjoyable.

So about 15 months ago I decided on an upgrade. The MDT30s were about 20 years old and probably past their best, so I replaced them with new ET338s. Changed the capacitors from Ansar Supersound to Jantzen Silver z-cap and the resistors from Jantzen superes to Mundorf Supremes.

I can't tell you how disappointed I was with the sound. That ability to put performers in the room was diminished, piano sounded dull and rounded and acoustic guitar just sounded wrong. The sound as a whole was a bit light and 'weak', lacking body and dynamics. Very polite is a good description.

I've spent hours fiddling with the crossover to try and get back the sound I had. I did improve things but never felt happy. Along with the horrible thought of how much all the new parts cost I was about ready to give up. I even changed the caps back in case it was them, but it made no difference. Last week I came to the horrible conclusion that all else being exhausted, it must be the tweeters. So I decided to go back to the MDT30 and give them a try.

First problem to overcome was the cabinet. The MDT30 faceplate is quite small and no longer fitted the cabinet. Thankfully the faceplates on Morel tweeters have similar fixing holes and I was able to fit the ET338 faceplate to the MDT30 body.

So how did it sound? Firstly a slight negative: the MDT30 isn't as sharp at the very highest frequencies. It's a known MDT30 trait and isn't really problematic unless you are listening for it. But, and here we go, my 'in the room' sound was back, piano was full and resonant and guitars totally natural. Sax comes along with solidness and the ability to convey expression - much the same for vocals. Finally, I am able to relax and listen to music again!

One small added benefit. The MDT30 has an even low frequency roll off, but is a bit ragged. The different profile of the ET338 faceplate cures this though I'm not convinced it alters the sound in any way.

Morning and thanks for letting me join.I am not new to electronics,and loved tinkering for years but i am,i would suggest a novice.
I am currently learning from scratch using 'Al's electronic course on Udemy (not sure if this is known by you guys and if its considered any good).
I am learing just for my own benifit, to eventualy build something, repair items and just do it for fun realy.
I am currently repairing old NAD amps, particularly, 3130,3240pe and 3020 versions
🙂

This weekend I have completed F2J. The sound reminds me of my EL84 with no NFB, but with more details and tighter bass. Really sweet sound, the midrange is magical, female voices are perfectly clear and natural. I tried the amp with Karlsonator, but F2J waits for Alpair 12P in some fancy cabinet 🙂 I also tried with ordinary speakers with XO but as expected the sound was rather dull, too dark.

First Watt F2J with Karlsonator 0.53 3FE25 - YouTube

One problem is that - and it was also the problem in the simulation - that the pot is out of the range, so I can't set a perfect clipping - photo attached. So I think I need to reduce the value of R5 to 1.8k or... increase R4. Also, my JFET has the gate reverse leakage current below 0.3mA (at 25 °C, Vgs=-15V, Id=0), so I am thinking about increasing the value of R6.

Mr. Pass, thank you very much for this amp.

Guys, I'd like to get a somewhat portable system for driving a pair of Aurasound 50w 4ohm bass shakers, aka tactile transducers. I already have a big, heavy Crown amp but I'd like to go smaller and lighter. Before I waste time and money I'd like to know if a class D bass amp, such as the Trace Elliot Elf, could do the job? I'm wondering just how well it could handle it since the caps aren't that big so repetitive shaker "hits" might not be possible. I don't want cheap Ebay amps. I need something better built, which is why I thought maybe these small class D bass amp heads might do the trick. Any thoughts or suggestions appreciated. Thanks.

Hello, I am new here. Not an audio nut, but really like gear and music and love figuring out how things work. I came here to find out if I can fix a $20 thriftstore reciever to use in my garage. I need to figure out how to replace the relay. Looking forward to learning!

Has anyone modded one of these or rolled different tubes in this? I know that GingerTube has mentioned a Music Angel EL34 amp - that was a few years ago, but is it the same version?

Hi there,
is there a basic circuitry that completely eliminates a line level output transformer and behaves exactly like this, i.e. keeps the differential output level constant regardless whether one of both terminals is grounded or not? Quasi the opposite of an instrumentation amplifier consisting of three opamps...
Best regards!

i recently purchased a nad 3020 series 20 amp that was not working,mainly to see if i can get it going, a good learning tool for me, the problem is i am way confused.The service manual i have for it lists different components than what is installed, actualy they more match the 3020A, but even this isnt totaly acurate, so i am wondering if someone else messed about with it before me, which is very possible i guess.so i am at a loss which service manaual to use.should i totaly believe the original?.The other real issue is the little LED board that is installed.when you look at the parts list it shows for example that D803 should be a diode, but is in fact a 2w-680 ohm resitor, and C807 should be a capacitor, but looks like a diode
the service manual only goes up to C805.see attached.So as you can see i am a bit confused .com.

I have attached photo of the board and the 2 alternative parts lists

Appreciate any help or comments you may have, thanks, paul.

Hello.

From several month ago, i have found Class D amp for me.
Finally i arrived journey's goal.

For comparison amps, bought its from Aliexpress and ebay for 3 months,
TPA3116, TDA7498, TPA3255(EVM), TAS5613, STA516B (AB32516).

First time, i bought 3116, 7498. 3116 was just bought, not use.
7498, It's not bad. but, when it's bass sound reached some area,
gave feeling stuffy. maybe it was caused by circuit design and Chinese
electronic parts on PCB.

Then i wanted new 7498 have well designed circuit. But, by seller's problem,
it had to changed to TAS5613. It was better than cheap 7498.
i had used 4 months, But, still not satisfied in detail.

I gathered more information about Class D amps form diyaudio.
Got information 3255, bought it. and same time EVM, too. haha.
During wait delivery, i saw post mentioned AB32512.
I interested, but, there were 3 models 32512, 32514, 32516.
32512'sound quality was verified many people.
then i wondered how about 32516 in new line up.

Finally, i had six amps, tested, then concluded 32516 is best in i have.
3255 was good. EVM was better than 3255 from China.
But, 3255's tone was quiet for me. Both were same.

and 32516, it was good. powerful at all range, and detailed.
In long time, i excited first time.

my speaker's output is 100W. any amps can drive it in my small room.
Compared with amps' output, it not large. it couldn't make 32516 warm.
it stayed in cold. same reason, Meanwell 600SE-48 was overpowered.
Too much fan noise, i installed fan controller, then down fan speed to lowest.
But during play music, it stayed in cold, too.

Someone interest to 32516, i recommend smaller power than expected.

Hello, im debating, building a line array. I would like to try a design that has been built and tweaked. I mostly listen to folky male artist Ray LaMontaign, type music.
My room is a dedicated hometheater that sounds great, but i would like more. Im definitely doing two different systems. One audio two channel and my existing 7.1.4 theater.
I like vintage type gear, parasound has some great powerful solid states and theres tons of tube preamps too.
I was looking at the chb-50 build by markaudio just beginning to look around