Controlling your Beheringer DEQ2496 from listening position to optimize the sound of your home Stereo System
By I.G and A.R - Rev.0 June 14, 2006
issi.geier@yahoo.com

Many audiophiles around the world are integrating the Beheringer DEQ2496 with there home sound system for optimizing the sound by room correction, system sound correction, sound imaging and "on the fly" improvements for far from perfect recordings.
Optimizing the DEQ2496 for room correction, system correction and sound staging should be done from listening position for best results.
Our ear and brain is very good with identifying a relative change in sound and imaging. Moving from our listening position in order to tweak and make a change with the DEQ setting interrupts with our ability for identifying relative sound change and resulting with frustration with our sound optimization process.
We want to keep the DEQ physical location close together with our CD / DVD players and our amplifiers. This enables us to have it connected using short high quality interconnect cables for best sound.

The solution is to have a remote control to our DEQ2496!!!

Two methods of remote control are presented; both were tested and used by us:
1. Separating the DEQ front panel and extending it with a long flat cable (5Meter) - It has a Low WAF (wife acceptance factor) -
2. DIY remote control using 12 Channels IR control Infra Red remote circuit, DC motors, solenoid actuator and Tape Recorder rubber belts - High WAF .

See attached file for details, pictures and instructions

All thoughts and comments welcome. Please help me point out problems, errors and suggestions for improvements.

The goal is balanced input, negative feedback and around 25-35 watts.

Per Eli Duttman’s suggestion in post #3 in this thread
https://www.diyaudio.com/forums/tubes-valves/349589-7591a-amp-design-35w-x2.html
I am incorporating combination bias for the 7591’s They will be new production.

New production 5AR4’s seem to arc over easily so i’ve added some diodes to help that problem.

Not sure I have the negative feedback exactly correct but hopefully it’s close. Everything else is pretty straight forward.

I plan on building 2 to make a stereo pair, Attenuator is stepped so stereo balance can be maintained across the pair.

Recently while working with a $2 Bluetooth board, I found myself digging through my drawer of wall-warts, and found a Motorola 180-0711 power supply from an old Palm PDA.

The sound was so much better than the smps I had been using, I decided to open this linear supply and see what it had going on.
The supply not only had a regulator, but a pair of inductors, multiple capacitors, an ic, additional diodes. While I haven’t traced the circuit to analyze things further, I did add a snubber to the main diode, replaced the main cap after the diode, and added an X cap for the incoming A/C.

Highly recommended for users of 5v line level devices, are available for around $10-$15 on the auction site. These are about 20 years old and will likely need the caps replaced, but are a relatively good bargain imo.

newb here, first post. I would like a simplified ACA wireing diagram to make the ACA one RCA only in, and only one Output. I want bridged mono only. I do not understand the use of the 39K resistor on the back panel. Do I need this for a simple monoblock? Thanks in advance.

I started out with the Salas Simple Shunt Regulator http://www.diyaudio.com/forums/powe...listic-salas-low-voltage-shunt-regulator.html but with a TL431 as the reference with a trim pot for an easily adjustable power supply however I really wanted to use lm329 but you don't have the convenience of adjustable Voltage Out like you do with TL431.
Then I had an idea...........

Here it is.
Simplified constant current source at input (I already have these laying around ie IXTH20N50D (not IXTT package)) it does the job.
D1 is LM329 but I don't have a model for it so I used a 6.2V zener just in simulation don't let that give you a brain melt down.
R2 is a 5k Trimpot set at 1k for around 24V out.
For a supply voltage below 24V either increase the value of R9 eg 18k or consider using a precision 2.5 V reference etc. There are quite a few different ways to achieve the supply voltage you require.






Output impedance.






Feel free to tweak this anyway you wish, I'm sure you guys can think of some improvements or modifications (I have thought of a few other ideas also)

😉

Gents, I just ordered 2 SCA kits. I have a spare 3 pin 19.5V 6.15V 120W power supply from Dell so I did not order the Meanwell 24v 5A.. I will be running a single ended stereo then balance monoblock at 8ohms. I read from SCA web site that the power supply is 19V for 8ohms.. Can I use my spare Dell power supply with the latest Rev kit? Answers or comments appreciated. Thank you

Hi guys,
Would it make sense to purchase an old pre-amp that has two phono outputs and upgrade the caps etc that are in the signal path or buy a dedicated phone pre-amp that can take to inputs for mm?

Pre- amp I have in mind is the Nicco TRM 500/600/700 series that would feed a Dynaco St70 valve amp and also a marantz pm 6004 amp & cd player by beens of a speaker selector switch.

Answer and recommendations would be gratefully appreciated.

Precision model 10-40 tube tester $40, in very good visual condition.
Will need checkout before use. Local pick up only, in the Madison, WI area.

See post#8 for photos.

Dear all,

is a 'super tweeter' something we might strive for in high-end audio ?

I mean tweeters which go up 'til 50-70 or maybe even more KHz in frequency.

We all know what's the max. freq. of a CD, we know Nyquist, sample rates, Hi-Res Audio and human hearing (I hear 'til around 16k at the age of 40)..

A friend of mine argued such tweeters might be good (even if the source will never play any signal into these lower 'ultrasonics') because of upper harmonics and we can feel them, allegedly.

What's the truth ? Do they make sense or is that complete BS and we're good with high quality domes, ribbons, AMTs etc. going 'til 20k in average ?

Hi everyone, I'm not really new here as I joined in 2012 😀 but have only recently started to become active. I've just caught the tail end of a group buy for a turntable speed controller created by one of our members, I'd missed the actual group buy but luckily another member had one for sale, result!

Which brings me to my question - why are PMs restricted to one every 20 minutes? Is this a default setting or does it change based on post count etc? During the discussions of the above mentioned controller I found I had to wait to send PMs, and was concerned I was coming across rude by not responding promptly to messages.

Cheers!

Barry.

I've never seen one but have read that they exist as they were around in the mid-late '60s.
So, anyone have any in their collection?

Thank you

I'm wondering why we don't see more car audio drivers suggested for open baffle bass.

I see the Eminence Alpha 15A suggested a few times ($60 at PE), but that has a low Xmax of 3.25 mm. For similar cost, you can get an Image Dynamics CTX128, that has the same impedance, but it's a 12" driver with a 16mm Xmax, which results in 2.5 times the linear displacement capability of one Alpha 15A, which should mean more linear SPL capability and cleaner bass at lower frequencies.

Another option is something like the Infinity 1262W. This is a DVC that's slightly more expensive, but it does provide the option of being able to "tune" the Q by simply not connecting one coil, or shorting one coil with a resistor to achieve a particular Q. Oh, and with its 12mm Xmax it has almost double the linear throw of the Alpha 15A.

Many of these drivers are designed for stupid people behind the volume controls so they should be sturdy enough for OB use.

My NAD 2200PE amp put out a really weird sound when I turned it on a while back. It was hooked up to my passive sub.
I've hooked up my Mp3 as a source later on, and some times it puts out this awful sound, and sometimes it does not. And, it will play music just fine.

I tried it a few nights ago, and it still plays music, no nasty noise. I don't understand what could cause this noise.
If it helps, a few years ago, I turned on the amp for my my sub and discovered the sub was blown. Weeks b/f the sub worked just fine. I replaced the driver, and all was fine for 2 years. That's when, one day, I turn on the amp and that awful noise was coming from the sub.
That's when I put the amp on my workbench where it's been sittin' lonely w/ nothing to do.
Could this be a DC offset thing or a bias adjustment out of whack? This is a class G amp, btw.

Hi all
This amp has AOT460 mosfets with 100ohm gate resistors can I use 3205 with 47ohms. Thank you.

Hi im looking for starsound boards driver cards and power supply cards

UPDATE 15-SEP-2019: deadline to commit to this group buy, see post 15.


I decided to order a batch of custom made "Pass Aleph style" heatsinks as shown in the attachment. The heatsinks will be black anodized, 200 mm tall.

Before going ahead with the order I thought I'd ask around how much interest there is for these. Maybe it's worth to do a group buy. Approximate costs depending on number of heatsinks:
- 20 pieces: 140 EUR / piece
- 50 pieces: 95 EUR / piece
- 100 pieces: 80 EUR / piece

(these prices do not include shipping, handling, tax and stuff)

If you are interested, reply to this thread add yourself to the list. This is not yet a final commitment! I just want to get an idea of how big the order might be.

mbrennwa / 8 pieces
mordikai / ??? pieces
gkirbyjones / ??? pieces
Zen Mod / ??? pieces
6L6 / ??? pieces

Hello,

The struggle with two nearly-born amps (if I'm lucky🙂 lead me to this question: What part of diy-ing do you dislike? If you love it all, feel free to build me a few amps, it's your pleasure!

Here's some of the things that annoy me:

- sanding the chassis untill it's showable (I use wooden chassisses)

- forgetting to order an essential component = wait another three weeks

- searching ad infinitum for a little spot in the too tiny chassis to mount a certain component (e.g. resistors to reduce heater voltage; heater trafo's)

- Getting the heater supply at the right voltage (this actually took me two afternoons with some additional problems....)

- The fear that one of the power trafo's will be badly connected and burnt to oblivion (I used to test old trafo's without using a fuse, hence my experience with and paranoia for smoking trafo's....)

- The fear that the amp will sound much worse than it did in the breadboarded version......

- The fear that things will fall apart....

But ofcourse that's all forgotten afterwards.... 😱

Thank you dear diy-shrink, I feel better now. Let's sling some solder!

😀

Simon

Hi,

I've got John's boards for the Aikido Octal (Oct 2018 design) linestage and ACF-2 buffer and while going through the design /parts realized all is not as it seems.

There are lots of errors in the documentation, not to mention missing part values and duplicates. I was wondering if somebody has already built the new 2018 boards ? Some help would be nice. Thanks.

Regards.

Hey there!
I've read trough all the synergy posts I could find on the forum and learned very much about the concept thanks to you guys!
I'd like to thank the developers of xsim and hornresp and mr.Danley for his work on multiple entry horns!

My synergy horn build consists of
1x1" BMS4550
4x4" Celestion TF0410MR
2x10" 18Sound 10W500

After playing around with the filter feature in Hornresp, I came to a point where the response is pretty flat.
For that I only use a high pass on the horn and a high pass on the mid.
As far as I understand and see from the simulations, the position of the entry points acts like an acoustic bandpass filter.
So is it necesary to lowcut the midrange speaker, as the horn already does that acousticly?

Does anybody have any observations?

Here's snaps from the Hornresp simulations:

Horn Dimensions:


Tweeter (BMS4550) 1"


Midranges (Celestion TF0410MR) 4"


Woofers (18Sound 10W500) 10"


Snaps from XSim:

Here's the layout:

Highpass at 2000Hz on the Tweeter
Highpass at 500Hz on the Mids
Lowpass at 500Hz on the Woofer

Frequency response of the filter

Cut it at 2k so it so it's easier to compare with the Hornresp freq response.
It's pretty flat from 2k on both frequency and phase wise.

The resistors are for some padding on the tweeter and midrange.

What do you guys think?

Is there any way to derate the manufacturer's numbers to come up with realistic TS parameters before buying?

I have all the test equipment to measure parameters once the driver arrives but last time I just ended up paying return shipping and being back where I started. The driver was so different than the specs that it would not have worked.

I was looking at buying the Dayton Audio DCS380-15 as an example.

I have a pair of speakers that use the discontinued Scan-Speak 21W/8554-00, but unfortunately one has just stopped working (no obvious signs of damage).

I was wondering if anyone knows of a source of this driver (in the UK), or might have suggestions for possible repairs?

Like many people in audio, Geno built what he thought would be a one off Digital to Analog Converter (DAC). Little did he know that would turn into leaving his previous life as a Computer Scientist and he and his wife Sherri starting Geshelli Labs.


Geshelli Labs | Ep 40 - YouTube

A company in CA is blowing out 12V DC 2A wall-wort type power supplies on eBay for a buck apiece with free shipping. Perhaps because they have a nonstandard output connector? Regardless, it's a handy-enough value to keep some around. I initially ordered a couple to check out. They came Priority Mail and they're good-enough little switchers, with about 1mV of noise over 100kHz BW while delivering 1/2 amp of output. There's no doubt the merchant is losing money on this, but hey...

AC Adapter 12V | eBay

I was looking at geoff's class-a site and noticed this amp. It uses jfet upfront, and is fully complementory.

I would like to know:

1) how does it work? it has a fully complementory vbe generator, 🙂. and it also has a very interesting feedback scheme. I would appreciate any insight into how it works.
2) I am interested in what has to be done to replace the jfets;
3) and I would also be interested to use some irfs as output devices, 🙂.

Any insight is apprciated.

Need to get a road case for my Vox AC15. Any recommendations on where I should get it from or tips on searching for one? I don't want a universal case and don't necessarily want to spend more than I spent on the amp itself haha. Thanks in advance!

Hello everybody.
Integrated amplifier TECHNICS SU 7600.
Protect relay not click.
If I activate the relay manually right channel ok,but -33.5v on left channel.
I desoldered 2 power transistors,drivers no problems,all parts are ok,no blown fuses or resistors.
Thanks.

SM

TECHNICS SU-7600 SERVICE Service Manual download, schematics, eeprom, repair info for electronics experts

Hey guys,

I started thinking about building a Dual rectifier and I found some schematics for the 3 channel solo head.

I decided to redraw them in KiCad both so they're easier to work with and also because eventually I would need to make the PCBs.

So far I've found one thing I don't quite get.

Can any of you wiser than me tell me where the " 1' bus " (down-right) is connected to?



It's totally possible that I am missing some stupid detail.

Thanks a lot.
Tomas

Hi,

I've lived with this as a plate load for some while. Low capacitance and high impedance with the 'mu output' for low output impedance, whats not to like?.

Have recently acquired a good Tek analog scope, and I'll let the pics tell the story. I constructed it using perfboard layout as close to the original PCB's and used the recommended parts. Yep, it sounds great.

With mu output there is a voltage gain of 6dB at 500kHz, and square wave rings (at any frequency), screen shot is 1kHz.

Taking output from the plate of the tube (at the 'bottom' of R1), all is clear up until well past 1.5MHz, the stage starts to roll HF off at a tick over 100kHz, and down by 6dB at 250kHz there abouts, no visible distortion of sine wave at all, until it rolls completely off well below 2MHz.

Any thoughts?.. buy a CCS kit that doesnt oscillate, yep.. but the super low capacitance and high impedance is what attracted me to this years ago. Could it be (and I'm not a SS guy), simply a matter of increasing the stopper to 100R or 1K in lieu of the 10R as specified.

Anyway, hope someone finds this useful and any information, suggestion is much appreciated. .. Gary are you still around??

Thanks.

Hi all, I have this old NAD 3020 which I am refurbishing. I want to recap it with Nichicon audio quality caps, but I am not sure exactly which caps to do. I am sure lots of people already did this and might still have a list of which caps to replace. If so please pass it on as well as any other tips and advice would be appreciated.

Thanks in advance.

Hey,
I’m looking for a digital volt meter for testing an f6 amplifier. I need to set bias and offset accurately. I have a fluke 110 but don’t think it’s accurate enough. I’m not opposed to buying something used or older but it has to be reliable and accurate. I can probably spend $100-150.
Suggestions please

Seeking comments about Toroidy push pull output transformer for 300B project, nd would like to use 6.6K primary.

Tube output transformer [6,6kOhm]

Any good??

Hello everyone,

I'm curious if anyone has first hand experience with Radian's new ribbon elements. They have released a line of planar ribbon high frequency elements and also released a line of coaxial speakers that utilize these drivers for the tweeter. They also have waveguides for the ribbon elements that could be very useful.

From a lot of reading it seems these drivers have had a lot of thought put into them. One of the designers seems to be Igor Levitsky who was involved in BG and SLS.

Overall there seems to be a lot of love for the BG products. I'm surprised to have not found more experiences of working with these drivers around on forums, especially considering their rather reasonable pricing.

If you have heard one, worked with one, or have any thoughts I would love to hear about it.

Here is a link to the ribbons Ribbon - Radian Audio

Here is a link to the coaxial with ribbon tweets
Coaxial-Ribbon - Radian Audio

(Note: I'm putting this in Multi-way due to these likely ending up as a component in a bigger multi-way system. If this needs to move go ahead and my apologies.)

I’m looking for a recommendation for a digital volt meter suitable for testing an
F6 amplifier? I currently have a Fluke 110 but I don’t think it will measure accurately enough for setting the bias and offset. But I’m not sure. If this can’t handle it I’m looking to pick up something, probably used that is reliable and accurate. I’d like to keep the cost around $100.
Suggestions please

Hi,

I have an Hitachi HA-4700 that sounds great, but the left channel is about 1db down, all across the frequency range. I have recapped it and set the bias. I checked the preamps and both have identical output. The power rails are also identical. I also changed all the fuse resistors in the power amp stage. I'm beginning to think it must be one of the power transistors or the volume pot (which would be impossible to get). I replaced the balance pot a while ago, so I know it's not that.

Anyone got any other ideas?

Cheers,

Theo

Hi folks

I bought one of those 'JLH 1969 Headphone Amp' PCBs from ebay, which isn't actually a design by JLH himself, it just uses the 1969 design as a basis.

I went to the trouble of sourcing all original components, NOS transistors, Wima and Rubycon caps, Neohm, Welyn and Vishay resistors, no cheap Chinese parts at all (other than the heatsinks).

For a chassis I took an old Show PA-18 mono PA amp and stripped it down, then bolted a 3mm piece of aluminium on the front.

Last night I came to fire it up for the first time and when I hit the power switch, the blue led came on, but immediately, smoke was emitted, so I turned it off.

On inspection, two resistors have burned out, it was only powered up for a second or so, so hopefully not much else ha been damaged.

Anyone got any idea where to start diagnosing and repairing this thing? This is my very first ever amp build to reach completion, so I'm a bit clueless where to start.

I'm servicing a friend's Rotel RX-855 receiver.

It has two mains transformers - one for each channel. One transformer has only one output ie AC1/AC3 in the schematic. I think it provides +/- 40V DC when rectified.

The second transformer has failed (low impedance primary) and has two outputs, one the same as above (AC2 and AC4 in the schematic), plus an additional AC output (AC5 and AC6) which is used for additional circuitry. Can someone please confirm the output voltage for AC5/AC6 - I may need to source an aftermarket transformer if I cannot source an original. Or alternatively, point me to a source of replacement transformers.

I have been trying to find out why you would want to supply an amplifier with a ground lift achieved by a 100R resistor in series from chassis (earthed) to circuit 0v?

My power amp has this and my preamp does not. So of course the preferred return will be via the preamp input leads ground rather than the 100R to the chassis and earth on the power amp mains plug?

I have successfully reduced a bit of hum on my preamp and also had an unexpected increase in sound quality trying a low impedance earth connection like this article suggests - basically taking the circuit earth through a separate low impedance connection. (2 plugs on one amp)
http://tech.juaneda.com/en/articles/Ground_and_safety_earth.pdf.

I was going to try the same approach on the power amp, and discovered the 100R lift and wanted to understand why you would do this, and does it need to be part of a system approach, meaning you would want to do the same with the preamp if the 'lift' was for some reason preferred?

Thanks,

Hi there, just reporting some images not loading from a remote site on this excellent article page.

Audio Component Grounding and Interconnection - diyAudio

Thank you!

Good evening everyone. I am looking to sell some of my drivers I have on hand. I would prefer selling in 2 pairs if I can. Saves on shipping. I will only ship to the 48 United States. Buyer pays shipping unless it’s over $600.00 then I pay shipping. Please e mail if interested in asking what drivers I have for sale?

Here’s a few fostex drivers for sale?

1. A pair of Fostex FE208NS drivers new. Asking $400.00 you pay shipping.

2. A pair of the Fostex FE208NS Sigma drivers and a new extra one for a back up. Comes with 3 fountek Ribbon Tweeters. They are the bigger ones. I paid around $120.00 each tweeter. They are brand new. Asking for all the drivers $650.00 for everything. I will pay for shipping.

3. A pair of the Fostex FF225wk brand new. Asking $140.00 you pay shipping.

I have more Fostex drivers and mark Audio. I can send pictures if needed. You can p.m. me or e mail me. Thanks Jeff

Hi folks,
I got a 60W mono Amp with TPA3118 chip that doesn't seem to work. There's no signal whatsoever coming out of it. The power LED is on though and I can measure 24V in several random places on the board. If I connect the driver directly to the line out of the Bluetooth receiver, I hear music, so the amp should be receiving a signal.
Do you have any idea how I can figure out what's wrong?
Here's an image of my setup: 20210927-215911 — ImgBB

Thanks in advance!

SOLD.
Thanks.

All sold.

Sold. Peerless NE149w-08. Pair.

Sold. Eclipse W6520-4.

Sold. DynaVox LW6004PMR-NC. Pair. Excellent. $80, shipped conus.

All cutoff at 100 hz to subs, so had easy time.

Thanks, Don

I got my 600VA 24V AnTek transformer today. I was surprised to notice that the input wires are 18awg while the output wires are 12awg. I would have expected them to be equal, or even for the output to be smaller. Why the large size jump?

I inherited a box of old tubes from an old electrical repair shop that was in a building planned for demolishing. Apart from a lifetime's supply of UY11 tubes (that would be more than 1!) and store cupboard essentials such as EN32/2050 ... ;-) ... there were a couple of transmitter triodes 8000 in RCA boxes.

I'd assume they were replaced as part of routine maintenance, so probably used. They are dated from the 50's.

Looking at the tube data it looks like they could be used without having to have Frankenstein re-animating voltages - say 750V - so I was wondering if they could potentially be useful.

Hi guys,

I'm trying to repair a Linn AV 5150 subwoofer with hum. I acquired it from a gentleman here in Dallas. He tried to repair it unsuccessfully and was simply fed up with it so I picked it up trying to have some fun with it and maybe learn a little bit about electronics along the way.
When I inspected the board I saw a bad thermistor. (I was told that the board was sent to a repair shop where they replaced the capacitors and the board was tested OK). Any ways, I have the schematics for the power supply, the amp, the LED and the Fan controller. The schematic for the power supply shows a temperature sensor where the bad thermistor is. I have very limited education in electronics so I can't figure out the specs for the thermistor just by looking at the schematics. Can anyone here give me a pointer on how to take a guess at the specs of the thermistor?

BTW, Linn is no help. I sent them an email couple weeks ago... They haven't responded.

The attached PDF shows the temperature sensor on p. 3 where the thermistor is highlighted.

Any help is greatly appreciated. Thanks a bunch in advance.

I don't know jack about tubes or tube amp design. But I do know that KT120s and KT150s are capable of producing higher output power levels from some basic research I have done. Does anyone know of any kits or plans to build up monoblocks that can produce >150W @ 4Ω? I have too many projects going on right now to spend the time to teach myself tube amp design from the ground-up, so I'm looking for something that is like a "turn-key" type of kit/plan.

I am searching for a high quality stereo audio ADC for the Pi. There seems to be lots of DAC boards out there (HATs and USB based) but only know of one good quality USB dongle with stereo input (Behringer UCA202) and two HATs with stereo input (Wolfson Audio Card, and the Audio Injector HAT by Flatmax studios). In terms of THD or THD+N these are not bad (THD+N is around -80dB to -85dB). I would like another 10dB or more.

The idea is to build a preamp (analog and digital inputs) around a Pi 3. This would stream audio over a wired or wireless LAN connection to clients, with a Pi 2/3 in each loudspeaker and subwoofer. The number of clients can be increased by adding more client PIs. I already have the streaming audio part working.

I currently use a BayTrail Soc computer for input under running Ubuntu Linux. A PI could do this just as well, and is better suited to embedded applications than a desktop computer and OS in many ways.

Does anyone know of a higher quality stereo ADC for the Pi that might work in this application? This seems to be a niche that has not yet been filled. Also, I would prefer something that doesn't require a custom kernel...

Another approach would be to use a standalone analog to spdif digital converter and an spdif only input on the Pi. Sample rate out of the analog-to-spdif would need to be at least 96k, however. Any suggestions on that are welcome as well. Thanks.


.

DJ Subwoofer Replacement Pro Audio 12" PA Sub Woofer Loudspeaker Equip – 5 Core

Anybody ever tried these? A pair is $54 U.S. shipped. I am thinking of doing a open baffle project using them. They are from India. They do not list any T.S. Parameters or F.R. graphs. Not a good sign, I know. I know the Betsy's and LTA, and A.N. 12" drivers are available but I am broke. $ 54 won't bring the wife down on me.

I just became aware of this web site:
The Audio Amateur Home

So someone has bought a domain name. Have they bought the rights? Or are these magazines in the public domain?

Hi errybody, I've been lurking around here for ages, been tinkering with all kinds of things audio for ages and making speakers for a... a while?

I saw something interesting that possessed me to post here: fuzzy FFF 3d printing. Speaker baffles, enclosures and waveguides with rough textured surfaces might have some interesting properties....

Which also got me thinking.... could one print something like an acoustic binary zone plate for a full range midrange driver?

I am having a problem with one of my Classic 150.

Upon turn on the High Voltage (Screen) LED immediately goes into dimmed mode indicating protective shutdown.

This usually happens when it has been played at excessive levels and the amplifier goes into protective shutdown. The reset process when that happens is to shut down the amplifier and wait for about 30 seconds then restart, the fault normally clears.

I cannot get the fault to clear.

I have checked the following:

-replaced speaker with 4 ohm load resistor, no change
-disconnected input cable, no change
-tested all 8 power tubes (6550), all test very strong
-spoke to ARC, they had no ideas

Prior to not using the amplifiers for a while I thought I noticed that on occasion that mono block tripped the protective shutdown at much lover listening levels than in the past, at the time I thought that I was merely 'imagining' it but perhaps this was a symptom.

Any suggestions?

Just finishing the set-up [ YES Again} of the new H/T amplifier and as it's a cheap unit is doesn't have inbuilt DSP bass management.

On a very tight budget as usual so I'm looking at some options at the cheap end on the market.
One option is the Dayton Audio LF-DSP[ $150-] but on Gumtree I just found a used Behringer UltraCurve Pro DSP 8024 selling cheap at $130- which is the same cost almost as the Dayton unit

Dayton Audio DSP-LF Low Frequency DSP Controller
Just wondering if I should take punt on the S/H unit and its probably steep learning curve or go with the dayton unit??
Comments welcome as well as advice

Hello everyone!

Well it's been 10 weeks in the making with a lot of learning along the way, but here I present to you the:




We were given these speakers and narrowly saved them from being taken to the tip. They appeared to have water damage, many dents and scratches, the grilles were torn and ragged and the mids/tweeters were damaged. Liking the look of these older speakers and being drawn in by the 12" woofer, I wanted to do something to save them.

I would like to say a massive thank you to system7 and Galu for all their help and advice along the way, as well as raymondj, planet10 and everyone else who contributed or offered help and suggestions. It would not have been possible without you!

The Goodmans Magnum-K2 is a large (29cmx38cmx61cm) chipboard cabinet 3-way finished in teak veneer and is understandably very heavy. It retailed for £46.20 in 1971 and it's specs are:

Impedance: 4 - 8 ohm
Max. RMS power: 50W
Frequency Range: 30 - 22,000Hz
Sensitivity: 2W produces 96dB in the average domestic listening room

(Thanks Galu for finding the above)

Here is a brochure page for the range of Goodmans speakers at that time (thanks raymondj):



Here is the original thread: https://www.diyaudio.com/forums/multi-way/374378-restoring-modifying-goodmans-magnum-k2s-advice.html


Modifications

• Crossover redesign (thanks Steve!)
• Relocate crossover to bottom of cabinets
• Upgrade internal wiring (2mm)
• Construct mid enclosure
• Replace mids
• Replace tweeters
• Strip veneer and refinish
• Restore/add black paint on baffle and grilles
• Replace velcro on baffle and grilles
• Replace posts
• Alter the way the bass driver is secured
• Filled various imperfections, especially on the rear of the cabinets
• New gaskets
• Add additional dampening material to the internal walls
• Recover grilles with new foam retro fabric
• Custom grille badge

The above is a summary of the main changes, but I am sure there are other little things I have forgotten.


Replacement Drivers

The mids seemed to have extensive PVA glue on them from some sort of repair, and definitely sounded below par to me. It's possible they sounded as originally intended, but if that was truly the case then I wouldn't rate them very highly. The tweeters may have been ok, but they looked fairly poor cosmetically. We decided to replace them both.

The drivers used are the Faital 5FE120:



and the HifiDIY X1II:



Using this tweeter, the frequency range will improve slightly to 20 - 22,000Hz

The original crossover looked like this:



It was located on the small piece of removable ply board that the posts are attached to.

Diagram of original crossover:



Please excuse my rubbish scribbling!

With the help of system7 (and Troels by proxy? 😉), we ended up with this:




Cost

By all rights, this probably should have cost more. But Freecycle/Neighbours/The Shed yields wonders from yesteryear, a failed project, some spares left over etc. I begged, stole and borrowed quite a large percentage of the materials needed for this, and the total cost ended up being just over £200, I am sure if I had purchased everything it could have easily been double that. By FAR the most expensive components were the Clarity Cap ESAs at half the total. The Faitals were a quarter of it at £51. I am sure this could be done even cheaper still if NPEs were used, the Tweeters weren't replaced and some things were ignored/skipped.

So without any more delay, lets have a look at some:


Build/Process Pictures 🙂

Original cabinets and condition they were received in:



They've seen better days!

Pretty ugly chocolate mousse brown rear panel:



Both drivers looking damaged or worse for wear:




Stripping the cabinets


Most of the stripping has to be done via the bass cutout. Removing the tweeters was easy. The mids were a little adhered by their very old gasket foam tape but did come out with a little persuasion. From there, you can place your hand in and push the large bass driver from the back. The crossover, wiring and 2 large foam pieces (per cabinet) have to come out via the bass cutout. We did briefly consider altering the cabinet so the back was removable, but in the end it seemed like it would be too much hassle and needlessly weaken what is a very strong cabinet. You can see that the teak veneer has a very red colour to it, and that the baffles were a very faded black. There were a large amount of staples that needed removing (from the velcro strips) this was not fun!



Because they were obviously allowed to get damp at some point, the LARGE amount of foam in the cabinets had a VERY strong musty smell. They were in the house when we first got them, and coming downstairs in the morning was a little unpleasant. We quickly moved them to the garage. We treated the foam with vast amounts of bicarb and a good airing on sunny days.



Here we had sanded the veneer (something which we later found out you SHOULD NOT DO!) and the baffles in prep for painting them black:



We also sanded the awful chocolate mousse brown backs which were just painted chipboard and filled a lot of bumps and dimples in the chipboard round the edge:

[url=https://ibb.co/D4kZnrq]

We also noticed when removing the bass drivers, that there was some corrosion to the metal at the rear of the drivers:



We didn't want this to continue so we used some hammerite on it:




Painting/Dying

One of the things that we wanted to do was get rid of the red wood. Neither myself or the wife are particularly fond of red wood, so a darker brown was chosen. We started off using an acrylic based paint to paint the veneer. This ended up looking absolutely awful:



It wasn't a problem to remove, though! It peeled straight off!



We changed course, and went for a dye this time. To start with, we stripped back the cabinets as much as we could and bleached them:

[/url]



We started applying Littlefair's wood dye (a fantastic product) and this was all going very well....



UNTIL... we waxed it:



Total lack of experience on our part, but the wax ruined what had looked rather nice. It wrecked the finish and made it look patchy and awful and to our surprise (despite the bleaching) showed a lot of the original red!

At this point we honestly thought it was game over! I contacted the company who made the dye for advice and they said that not only should be not have sanded the veneer (scrape off the excess wax and clean) but they would finish it with a dye mixed with polyurethane and acrylic. They said all the wax would have to come off first and gave some advice on how to do this.

Copious amounts of white spirit to dissolve the wax, then (if it will take it) washing up liquid and water plus LOTS of kitchen roll. We used the white spirit and were pleased, then moved onto the washing up liquid. This was causing some issues and we decided that it was getting too wet (something we had been warned about). Thinking that things couldn't possibly get any worse, we used citrus Swarfega with grit in it as it's more like a paste, strips oil based products and contains citrus which is a good cleaner... and..... this did the trick:



We lightly scrubbed it with an old nail brush and you can see how much is coming off on the kitchen roll:



And after applying the new dye with polyurethane and acrylic in:



Dyed, varnished and protected in one! We applied this one sparingly with a cloth in several layers. Phew!

We used this dye and varnish combo on the backs to get rid of the horrible brown:



Finally, we used black acrylic spray paint for the back of the grilles and the baffles:



The baffles and were given several coats of clear polyurethane varnish as well as the yellow paper the posts are sat on.


Mid enclosure / Driver Replacements / Crossover

The Faital 5FE120 required about a 5L enclosure.

View from bass cutout:



We started by using a cardboard box to see what size MDF we would need to get from the shed:



Then cut several peices BUT we had to assemble them inside the cabinet, which was lots of fun 😛



Done!



We fixed in place and sealed with a LOT of hot glue and liquid nails:



This presented a problem... the way to secure the bass driver was to put your hand in through the mid cutout and use a stubby screw driver to hold the inverse facing screws/bolts whilst tightening them from the front with a spanner or socket. So remove this issue, we used liquid nails to fix small chunks of MDF behind each screw hole so that we could secure the driver from the front:



The cutouts were too small for the replacement drivers. Not by much, but the original Goodmans mid was 4" and the new Faital is 5".



The tweeter (which I got cheap from a friend who ordered the wrong size) would technically fit, but when I got it I found the spade connectors stuck out a little. The tweeter cutout would need a couple of notches to allow the connections to sit without being mangled. We had to make these notches top and bottom as opposed to left and right because the mid enclosure would be in the way:



Mid cutout increased:



Of course, the cutouts in the grilles would have to be increased and the black paint touched up:



And here's some of the grilles being refoamed:

https://ibb.co/2gX9D4R

I got given some 5mm grey foam (for upholstery?) and we just used PVA to adhere it to the board once they were sanded off:

[/url]

Cutting foam is not easy without tearing it!!

The grille fabric we ended up using I also got given:



We love the retro look of it, and think it matches the darker dyed veneer. I’ll save pics of this on the grilles for the end 🙂

I recently picked up a pair of 2SK82 vfets, and it occurred to me that I’m halfway to what I need to build the 2016 Sony DIY amp.

PM me an asking price on your spare pair of 2SJ28. Or if you’re looking for a trade, I can offer a curved tracer matched pair of Semisouth SJEP120R100.

My moms threatened to toss them out, nice cabs but need new mids and tweaters , maybe I could hide them somewhere until can get new drivers cheap ..
Maybe as a stands or something.. not sure if there worth fixing at all but bass drivers work .. surrounds were shot on everything else .

Hello,

I have a JVC AX-2 with problems on the VC5022 IC, but it doesn't seem to work, I inverted the IC channels and it worked perfectly. I did a lot of research and I couldn't find the original IC for sale, there are only fake or defective ones on the market. Does anyone have a schematic of this IC to build a PCB to replace the IC?

I don't have much knowledge in electronics, but I believe I can build a PCB, I just can't find any schematics with the components.

thanks to anyone who can contribute!

I would like to buy Rod Coleman shunt cascode pcb V4.

Art

Hi all,

I'm making a PCM1794A project without the board and cost cutting limitations of the Chinese modules. It's for personal use but I'm wondering if there's demand in which case I could run it as a small commercial venture.

I'm a part-time electronic engineer, more digital than analog but it's easy to do with the datasheets. All digital chips are Texas Instruments apart from the MCU. Here's the spec:

• 2x balanced outputs, 132db/A
• SPDIF 50PS jitter.
• I2S pins if SPDIF isn't soldered.
• 5v input, can be VBUS and noisy.
• Very low noise LDO's for the 3.3v and 5v audio rails.
• 6x NE5534 or equiv.
• Panasonic 2% film ciltering caps.
• MCU for audio power stage shutdown after 3 minutes.
• Dual 12v/-12v boost & inverter, low ripple.
• LED outputs for power, standby, error, receiving.
• Very small size.

Active power consumption = 5v, 0.67A
Standby power consumption = 5v, 0.02A

I'm using SPDIF but it's becoming difficult to find motherboards with this connection. HDMI requires an extraction chip and introduces jitter, USB introduces complexities for Async mode and most vendors lack specification details. I still concluded for stereo SPDIF is the best source.

I'm also using only a balanced output. I use Adam Audio speakers which in my opinion are the best speakers in the world at a given price point. This however will hinder those without balanced.

Any thoughts, reflections, guidance, much appreciated.

Board pictures are without silk.

The listing:
240V (International) Edelweiss-3 Preamp Plus. Class A1 OTL vacuum tube Headphone | eBay
The review:
WAVEBOURN EDELWEISS-3, HEADPHONE AMP/PRE AMP (FULL REVIEW). - YouTube
Explanation of differences of 2021 prototypes:
Edelweiss-3 2021 production prototypes - YouTube

A friend of me will connect this cartridge (4mV output) to the MM-input of Linn's LK-1.
In genuine condition there is an input load of 68pF and 100K (instead the most usual 100-150pF and 47K).
The recommendation input load resistor under
Grado Labs - Sonata3
is between 10K and 47K (a wide range).
But no value of "pF" is mentioned.
Who know typical values for this cartridge ?
Are there anywhere diagrams of this cartridge with use of different load values ?

Thank you very much for an advice.

My speakers (Vandersteen 3A) use terminal strips with screw bindings for the speaker connections, and I love how tight and secure they are. I'd like to use the same strips for my amp project, but I can't find any that are spec'd for a 1/2" spade. I've posted on the Vandersteen forums, but so far no luck. Does anyone know where I can get something like this? Mouser doesn't even measure the channel width.

Hi everyone!
Im working on a jl audio xd600x1.
Im ready to solder the ir2101 but i have a diode in short. Part number is D15.

Anyone have the value?

Thanks

Hi all, I'm a newly register member to this board. I hope I am welcome here even if I am not electrically trained.

Has anyone heard this new Pass Labs X2.5 pre-amp? How does it sound compared to the X2 it replaces?

I have a BAT VK-20 pre-amp driving the BAT-VK200 power amp and I'm thinking of upgrading to a Pass lab pre-amp. Will the new X2.5 be a significant enough improvement or do I need to go to double decked X1? Space is a concern.

I am currently experiencing a loss of low level details, and I find that the BAT VK-20 needs a long run-in time, after turn-on from standby to sound it's best.

My friend showed me the schemetics of the X2.5 and it shows much simpler circuitry layout than the X2.

Will there be a new X1.5 to replace the X1 soon?

Appreciate any comments.

Hi Members.


I'll be soon re clothing the speaker covers of my B&W DM110's.
The frames a plastic of some sort and I have regular speaker cloth.
My brief is to successfully glue the cloth to the frame at minimal cost, & I want to avoid staples


What type of glue can I use?
I have Crafters Choice Tacky Craft Glue, & Selleys PVA glue.
Are these suitable?


.


Thanks.

WTB: Philips CD POR-2 transport assembly in any condition or Servo Drive board with 6.8 version.

Do I look at the FR curves?

This is for a 2-way and the good folks at minidsp suggested an active crossover. They told me their OpenDRC-DI is made for 2 channel stereo. The nano is multi-way.

I just want to use their OpenDRC-DI for parametric EQ of the woofer running full range. I have the tweeter on an LRC circuit now.

I just received an early HP 201C oscillator, looks to be a 1957 unit based on the tube date codes. It needs the usual rehab (caps, cleaning, etc.) but otherwise appears to be in solid shape.

One issue is that the vernier shaft is siezed up; it won't turn, and it's stuck in the disengaged position. I tried to saturate it with PB Blaster overnight, but that didn't free it up.

I'm not totally familiar with this mechanism, so I'm not sure which way to try to "persuade" it. It's stuck with the knob flush against the faceplate, and the flange not in contact with the main dial; am I correct in assuming that it should actually be sitting forward of that? I mean, if I remove the main knob and dial, I should be able to tap the back (interior) side of the vernier shaft toward the front to free it up - is that right?

After reading already famous article by AllenB I decided to write alternative tutorial for those who'd like to take completely different path. I'd like to thank him for inspiration to do so!

INTRODUCTION: „For great sounding multi-way driver relative phase must be equal at all frequencies. Period.”

Typical approach in loudspeaker design is provided in many articles as follows: choose drivers, choose baffle, choose crossover point and filter orders, apply corrections. Phase is too difficult to understand, so lets omit that.

This one will be different as it will deal with phase alignment in the first place and only then all other things. This almost step-by-step guide is aimed for reader familiar with basic loudspeaker building principles, having moderate experience but still struggling with consequences of typical approach. I hope this article will be somewhat helpful or at least wake a challenge to try it and compare with previous results. So lets start with

BAFFLE STEP DIFFRACTION: use wide (~60cm) front baffle. Therefore LF roll-off will start under 300Hz where room modes start to help. This way you may avoid electrical compensation at all. Use two LF drivers instead of one as it will make matching even easier, especially with bipole push-push type design (one LF driver facing backwards, both in-phase) and give you additional LF sensitivity usually lacking in regards to tweeter. Gains: no need to introduce large inductance for electrical baffle-step compensation and to ruin transient response and sensitivity. Increased sensitivity for LF band; need for attenuation of tweeter level is reduced.

ACOUSTIC PHASE ALIGNMENT AND DIRECTIVITY: using shallow waveguide for tweeter will align acoustic centers by placing them on the same vertical axis and hence aligning acoustic phase (nothing complex here) plus it gives improved HF dispersion pattern. Gains: much wider listening sweet spot, airiness, less reflections from walls. Trade-off: slight roll-off of top HF frequencies (usually above 12k) and more pronounced 2k-4k region. So seek for HF driver with upward increasing frequency response if you want to compensate for that. Even with „normal” drivers I find benefits much more pronounced than this trade-off.

By placing HF driver on top of LF driver’s baffle within its own baffle will give you some space to fine-tune it's position after all further steps are done (so you'll end with what you started but on different precision level as you'll have speakers phase-aligned also electrically). See fig 29-31 here to get the general idea of acoustic phase misalignment side-effects. Make sure there is smooth transition without pronounced „step” between baffles. Also, HF baffle will benefit from thin soft damping material separating it from higher order vibrations coming from LF baffle so HF baffle and waveguide won’t be amplifying them.

To reduce LF driver beaming at 1-3kHz region rounded baffle corners with at least 10cm radius will be beneficial. Hard to build (at least from wood), that's for sure. Even if tweeter is capable and crossed low (below 1.5kHz) and have a very large waveguide (at least 30cm) round corners for LF baffle will give some dispersion benefit for midrange.

FLATTENING THE WOOFER'S IMPEDANCE: rule of thumb is to flatten with Zobel only to a some degree. Lets have it in detail. By using Zobel we get woofer impedance (and electrical phase response) ruler flat at its HF region. HF driver isn't impacted by LF driver’s Zobel so its impedance will be raising. Its phase will be shifted in the same region: Z and phase curves are following each other like twin-sisters. With flat LF impedance due Zobel at its max individual responses of both drivers in this region will be gradually getting out of phase in regards to each other ending with maximum phase difference up to 45 degrees at top end of frequency range. This will introduce unwanted additional HF cancellation and "lifelessness" in upper midrange as usually observed. That's why its usually suggested to tune R value for Zobel "by ear" by gradually increasing its value, usually without explaining the reasons why it should be done.

When we increase R value compared to „flat” version LF driver impedance curve starts to raise from being flat. With some optimal R value its phase curve will mirror that of HF driver. If phase nulls before impedance raise for both drivers luckily or deliberately are placed on the same frequency then with some particular R value of LF driver's Zobel they will get very close to being exactly in-phase at the whole top end high frequency region. Therefore individual driver responses will sum together nicely instead of response being gradually attenuated with increasing frequency as in case with totally Zobel-flattened LF impedance.

So we have are obvious gains here - electric phase gets aligned and there is less loss of HF energy for combined output (if any). Also, by increasing Zobel's R HF roll-down gets less steep for LF driver just because of less degree of shelved 1-st order filtering. It can be hard to find the best R value without seeing measured Z and phase curves, still with good ear it is possible to get pretty close. Do it by ear this time 🙂

FLATTENING THE TWEETERS IMPEDANCE: same as previous, except in this HF resonance region we'd like to see HF driver impedance as flat as possible as it overlaps with usually flat impendance (and phase curve) of LF driver in this very sensitive region both for ear and for crossing. Due wild phase swing peaks and dips in combined response are expected on both sides of tweeter resonanse frequency unless we flatten it by damping it with a notch filter (RLC series filter parallel to HF driver). This is the second part of key to getting drivers phase aligned (now in midrange region). RLC values can be calculated if you know Fo and Qes of the HF driver. Unfortunately these values may often be quite far from factory specs so results can be very erratic. I'd suggest to get free version of impedance analyzer (for example LIMP, part of ARTA software suite), solder five resistors according to LIMP manual, connect to sound card inputs and headphone output to see the actual Z curve. Play with R, L and C values. Start with R as average Z multiplied by 2 (16Ohms for 8Ohm driver), C ~5uF, L around 0.6uH. Change the values, measure again and see where it leads until you find the right values for flat Z curve around driver's resonance. Or calculate values according to methodology described here. Now when you have involved impedance measurement box, redo LF driver Z measurement after you flatten HF drivers resonance as phase shift may have been changed and LF Zobel will need to be corrected again to match the HF's phase.

Actually most efficient sequence would be to start with flattening tweeter’s resonance and then tuning Zobel for woofer. But it is always fun to see how close you could get by ear compared to measured optimal value, so if you want, take this little extra side-step first to test your ear 🙂

Note: Z flattening will also change rolloff slope of HF driver towards low frequencies. Usually it will get less steep and start somewhat earlier extending response more towards low frequencies. Depending on selected LF driver it may be beneficial for driver integration and transient response.

Should you use Zobel for HF driver to get its impendance straight? No, this will just lead to significant reduction of the upper HF output. But yes definitely in case you decide to add supertweeter to extend your HF range. In this case you’ll need to make notch filter for supertweeter to damp its resonance, then add and tune Zobel for HF driver to match supertweeter’s Z and also re-tune Z for woofer to match the same. In other words - get all "tails" tied together. This can bee seen as hint on how to align more than two-way speakers in general.

Series resistor (if any) must be put only after the hi-pass filter, and the filter component values must be corrected for combined resistance. If possible avoid using series resistor unless HF driver impedance is significantly higher and you want to match these to each other. Redo LF driver Z measurement after you implement series resistor to be sure that phase curves still match. If attenuation level must be even higher then calculate L-pad type of attenuation circuit. It means some resistance to be added parallel to HF driver (and flattening notch filter) most probably leading to overdamped resonance as the result. So after calculated L-pad is applied return to Z measurement and increase value of R in RLC filter to get back to flat Z around HF drivers resonance.

PHASE COHERENCE: must be achieved at this point! Will be fine tuned at the end.

CROSSOVERS: now that woofer and tweeter have flattened impedance and phase curves in crossover region it is easy to ruin it all by combining even and odd order filters for the drivers to match the different steepness of natural roll-off slopes of drivers. Don't. Orders must be the same type for both drivers as each order turns phase by 90 degrees. Doing the opposite would create obvious phase misalignment again. Its a good idea to start with finding naturally matching drivers that have natural roll-offs at about the same frequency with similar steepness so you can use same filter orders on both sides.

Regarding tweeter polarity: in case of both being 1-st order we have to invert the tweeter polarity as we have summed relative phase shift of 180 degrees. With both being 2-nd order – don’t invert (180+180=360=0). With third – invert again (270+270=540=180). With fourth - don't (even hope to build one correctly passively). Generally all filter orders higher then the first are said to negatively impact driver's transient response. Never measured it by myself, still i find first order filter to be the most pleasant sounding. With sensitive drivers (>93dB/2.83V) you can achieve decent sound levels without getting too close to cone breakup.

Crossing point: now when we have completely tamed HF driver’s resonance I see only few things that may prevent you from crossing even as low as at HF driver’s resonance frequency - distortion values typical for chosen HF driver and natural LF roll-off due small cone size. Isn’t that cool for a two-way anyway?

If you cross actively use 4-th , 6-th or 8-th order Linkwitz-Riley phase-aligned filters.

PHASE COHERENCE – FINE TUNING. Switch on pink or white noise generator for one of the drivers (or use radio hiss between stations), go to listening position and ask someone to marginally adjust tweeter’s position in regards to LF driver by moving it forward or backwards. The moment the speaker disappears you know that you have achieved probably the best you can make out with your with particular drivers, speaker enclosure and filter components. Repeat it with the second speaker. Connect the first one again and pull out your most loved records. Review tonal balance, airiness, imaging, presence.. you name it.

TWEAKING: any additional notch filters or series resistors applied for individual drivers after we have done phase alignment will ruin it. Still you can apply them to whole speaker as it will impact both drivers and their relative phase alignment will be kept unchanged, but absolute (total) phase change doesn't matter. So if you feel like having any irregularities in combined frequency output you can add baffle step shelving filter (parallel LR in series with the speaker) to compensate for lack of bass response and/or additional notch filter (series RLC parallel to speaker) to flatten obvious response peaks. But before you do that see if you can’t resolve these by mechanically improving drivers (by damping their baskets, etc) or just by changing speaker placement in room.

LISTENING: I'd say that without any measurement it is extremely difficult to detect the problems and get to their source.

First, your ear doesn't lie, but your brain most probably does.. at least for some time. Excitement of „new sound” compared to "old" will mask some of less pronounced problems. Still if there are problems, your brain will get tired by listening for longer periods, several hours are usually enough.

Second, your mind will adapt. You may like the sound for a week of lots of listening. After one weak break you may perceive your system tuning quite differently, perhaps less pleasant. Plus your speakers will typically sound differently in the morning (more harsh) than in the evening. So do the testing at time of of typical listening and take brake for at least one day in between sessions.

Third, your perception is loudness dependent. So test your system almost at the same sound level which you chose to be your typical listening level. If you like to do it on different levels then calibrated loudness correction must be put in place matched to sensitivity of your system and with input signal RMS (average loudness) leveled from one musical piece to another.

Also different compression levels and different tonal balance of recording techniques of different times will sound very different. That’s all too gets very complicated, I agree, but that’s about how we are built by nature and that’s how musicians’ and studio gear have evolved over time. Still I believe each of us can reach one’s „sweet spot” of necessary corrections combined and get our ears pleased.

EPILOGUE: This particular approach to loudspeaker design as a whole is new to myself. It came to me as the concept and became a method quite recently. Some parts of it have been covered in great detail by several authors. I devote this method to my grandfather which would have turned 98 today. He had „golden hands” and taught me patience working with lots of materials. Many thanks to him! And also thanks to Rod Elliott and Siegfried Linkwitz whose much more elaborate articles basically led me to create this very simplified one, and who found a time to answer me some of the questions personally.

That's about it! Questions, corrections and additions are welcome.

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I have been enjoying F5 and ACP for months now. I have build the chassis for ACP, remote trigger, switch and all works like charm, except...
I get hum from speakers. If nothing is connected or if only one channel (either one) is connected the amp is dead quiet. As soon as I connect second channel the hum appears. If I connect Chord Mojo directly, same outcome.
I did the test shown in this file and connected the inputs directly and hum appeared, same level.

Can you good people recommend any solution?
For internal wiring I used Mogami W2549 AWG22. Above linked PDF suggests using AWG14 wire for internal wiring to avoid Cross channel ground loop.
Any recommendations for the wires?

Here are the pictures if somebody can see something obviously wrong:

My method is to use a mirror to identify the first reflection point, then generally center the acoustic panel on that point. My speakers are ~19" from the wall, so there is overlap between the panel and the speaker.

Would you place the acoustic panels on the forward side of the first reflection point? Am I "waisting" material that's behind the actual reflection point/behind the speaker?

Hello,

Got a problem with my AVR1909. Problem began with unit going into protection mode after ~5-10 min. Checked power supply voltages and found that -15V is pretty low (~ -14), drops to ~ -13 and and around that moment protection mode kicks in.
Changed regulator (KIA7915P ->L7915CV, insulated central pin from radiator of course), got 0V on 15V rail. With this temporary setup (photo, only -15V regulator) and disconnected -15V pin from input board (tested that pin only when disconnected, i don't get it short to ground) i get constant -15V (looks like PSU is working fine?).

Any clues where to look next? 🙂 Thank a lot everyone!

Is 13ma to push 845 too weak. Has anyone installed this circuit? View attachment FB-211-845-115V-230V.bmp

Hi,

I have a pair of SEAS FA22RCZ that I would like to modify into a midwoofer.

I know this is a strange thing to do, so maybe I start from the beginning. I have a pair of SEAS22FRZ which I bought a long time ago. I like the sound but it is limited in its functionality as a full range. I missed the sizzle of a real tweeter and the bookshelf box i have for it is not big enough.

I am also a fan of Audionote AN-E speakers. They are just so pleasant to listen to over the long run, and in many hifi shows they are a quite a crowd puller. Even though there were other more dynamic speakers, louder punchier higher end stuff, this was the sound that I liked. So i was looking to make a clone inspired by it but i realised the driver is rather unique and it is not something you can buy easily.

So what I was looking for is a high efficiency 8" driver with low cone mass and powerful motor with a low Fs and a decent xmax. This is where it becomes interesting. Most 8" high efficiency drivers are pro drivers with a 95db efficiency with a high Fs about 70Hz. Most 8"drivers have a Mms of 20+ gm and relatively low efficiency. Most full range driver have low Mms, varied Fs but generally very low x-max. In the end I realise the driver to fit my needs is the one I already have which is the SEAS FA22RCZ with a Fs of 30+Hz, a xmax of 3mm and a Mms of 12gm.

I also intend to cross a bit higher at 4-5kHz, away from the sensitive band.

I am thinking of playing with it, since I intend of making use of it as a midbass, I want to see what modification to the cone that I could do to improve its performance further. I am thinking the "wetlook" to dampen the cone. But the real reason could be I kinda like the glossy look.

Just wanted to see if anybody has any experience with the wetlook? or coating the FA22RCZ?

Oon

$1750 shipped in USA (except AK, HI)

Shipping accounts for $300 of cost, so discount if pickup in Denver area.

These listed for $4600 when new.

There is scuffing in the clear coat on one side of one speaker. See pictures.

It's hard to notice these issues when they're positioned normally. I'm including the third party outriggers I bought to stabilize these speakers which cost around $175.

I do have the grills, also in excellent shape.

The Adagio floorstanding loudspeaker is a two-way transmission-line system featuring a 1.5 inch circular ribbon tweeter and dual 6.5 inch midrange/woofer "underhung" voice coil, ceramic-coated drivers. The three drivers are configured in a time and phase aligned D'Appolito MTM arrangement providing lifelike imaging over a large sweet spot range. The Adagio features superior cabinet construction and aesthetic contours that actually reduce cabinet diffractions.

Short review: Acoustic Zen Technologies Adagio Loudspeaker - The Absolute Sound
Very thorough review: 6moons audio reviews: Acoustic Zen Adagio

Frequency Response 30 Hz to 25 kHz (+/- 3 dB)
Efficiency 89 dB
Dimensions 48" H x 9" W x 13" Deep
Weight 78 lbs. each

I have the original boxes for shipping but that is crazy expensive, so pickup preferred.

Hi there, I have a question about diaphragm displacement when dual drivers are used in horn response. In the schematic the driver diaphragm seems to merge as one, and the diaphragm displacement window does not indicate that I am getting a reading for two diaphragms. Going on the notion that hornresp only sees one diaphragm, can I double the Xmax limit for one driver?

E.g. If one of my drivers has a Xmax of 6mm, can i now push the enclosure design to allow for a 12mm Xmax?

Thank you all for your time. 🙂

Amp does not produce proper class D switching even without the outputs in.

Driver board has been worked before - so condition is unknown.
I took out the outputs out of the board , they read just fine on the tester.

I've got some weird reading measuring the buffers - q24, q25, q27,q28.
DMM in diode mode -readings are between 156 - 264 depending which one i'm measuring ...i suppose they are kind-a dead. This seems odd buffers to die, but the outputs to survive.

As I can't find 2sb1236a/2sd1857a can I use 2SB649A + 2SB649A ?! Specs seems compatible ?

Schematics attached.