I have an older Parasound HCA-1000A power amp that has developed an issue where it's red LED "Standby" light is on all the time now but I'm still getting sound. The amp was modified years ago but never exhibited this issue until recently. Typically, when working correctly, when powered up the amp displays the red standby for a few moments while the relays are working and then you can hear a click and the red light goes out and the green LED "Normal" indicator comes on. Here's the weird thing. I noticed that when I disconnect my interconnect from the amp to my preamp the amp does not display the red LED standby light, it actually goes green and I hear the relay click. So, when the amp and preamp are connected with an interconnect I get the red LED Standby light (though I still get sound). It doesn't matter if preamp itself is on or off by the way, it exhibits the issue. I did try another interconnect just in case by the way, made no difference.

Here's a snippet from the Parasound owner's manual:
-------
The Standby LED will also light whenever there is a short circuit or other fault that triggers the protection circuitry. This may indicate that excess DC is present at the amplifier's input, a speaker impedance overload, a short circuited speaker line, or possible internal fault. If this LED remains lit, remove power to the amplifier and check all connections. During this time, the protection circuits should automatically reset.
-------

Once again, never had this issue with this amp over the years until recently, suddenly out of the blue. Seems to be related to the RCA inputs and my preamp's output. Since nothing has really changed in my setup is it possible that perhaps it's a relay or maybe even a cap associated with/near a relay is out of spec and and throwing the red LED? Odd thing is I still get sound, the amp's output is not muted in protection mode. I do not get a huge thump when I turn this amp on by the way. Any help would be appreciated, thanks!

Hi

I'm moving to a much smaller place and my old center channel simply does not fit in with my plans for the new place what so ever.

I would really like a very thin/shallow of 76MM(3") at most. I've found a few center channels that are that thin, but they all suffer from one or more issues.
Ugly, expensive or just not available here in Denmark.

I'm currently looking making a center speaker in the style of the Beosound Stage soundbar using 2 Peerless HDS(Or SLS) 134 (5.25") units. Since they are not vented to the back of the magnet system and shallow enough for the case. Maybe also play around with some passive radiators

If you know of a similar project or some drivers that would fit such a thin case. Please let med know, any help would be greatly appreciated. I've looked at an insane amount of speaker units and the Peerless units seems to be the only ones suited for this project

1) right angle acoustic suspension / air compliance
2) cardioid u-baffle full range
3) fun w paper horns

Hey all,


I am in the works to start building Hypex NCxxxMP based amps in the US (just got my OEM account approved and have a mock-up for my case being worked on from Protocase). I am making a list of all the parts I need, but the only two things I am having trouble acquiring are the female connectors for the J4 and J6 H Box connectors.


I have the exact male connector parts from the Hypex datasheet, but all I can find are ribbon cable female connectors. Since I am doing XLR only builds, I need connectors that can have my own wiring connected, just like the Ghent Audio cable harnesses.


Does anyone have an exact match part for female connectors that work with the J4 and J6 H Box connectors that allow for individual wiring with crimp style connectors, much like the power and audio out connectors on the board?


Thanks!

one of the channels starts squaring the sinewave at 13vac . The other channel goes to 36vac without distortion. Also its drawing .03 amps without the remote applied. I discovered the 4 drive transistors in the pic heating up so im assuming that's where the current is going. I replaced all 4 without any change.

my Kenwood A94 Amp has stopped outputting music to the surround speakers.
Main speakers and center speakers work fine.
When I stop the CD, Vinyl etc and turn the main and rear speaker volumes up and down I can hear the surround speakers hum. So do I have a capacitor on the surround channel breaking down or something else.
Derek

It seems my "Save Session" button is missing. Anyone have ideas about what I can do to get it back? I'm using Excel 2016 x64.

As I have way too many speakers - they are going for sale: 400,- Euro incl. shipping in Europe - Mini Monitors as described in this link: https://www.diyaudio.com/forums/mul...tion-designing-crossovers-measurement-70.html

Hello!

I'm quite new here so I wanted to introduce myself here. I'm 24 years old guy from Finland, currently working on a building acoustics / HVAC company. I'm almost a M.Sc. in acoustics and audio technology which gives me a lot of understanding about some theorethical aspects of audio things. However, I see that real practical experience often gives much more overral umderstanding on what actually works, and in that sense, I'm still a beginner.

I'm interested in many kind of diy-projects, mainly related to audio devices. I still don't have very good woodworking places or tools, so I especially enjoy all creative, relatively low budget diy projects, where I don't need any expensive tools, but where I can really make use of my small dremel 🙂.

I've already made couple of threads (one related to my current DIY driver + aperiodic box project) and I'm positively surprised about the friendly and helpful atmosphere.

Edit. Also, I forgot to mention that I enjoy making music! I don't want to push too much and bother others too much with marketing it, but if you're interested, just search my name on Youtube or something. I mainly make electronic music.

Hello guys, as per title how would you judge the measurement of my listening room from the sweet spot?

I attached the 2 channels (L/R) REW files. There is an emphasis between 100 and 200hz but i think it can be speakers design...i still don't think it's a big issue.

I don't know about decay and sub integration (crossed over at 75hz) as I'm not yet expert with reading these values in REW...

The room has a lot of Bass Traps but i could not do much because of the shape (it's an attic).

What is your opinion?

Thanks


LR - REW.zip - Google Drive

Which tubes with a 3,5kΩ 50w push-pull transformer.
Any ideas ?

I am thinking of building an amp for driving the electrostatic panels of my ML Aeon hybrids.


They aren't an easy load, with the impedance dropping to below 1.32r at 20khz, but the crossover is at 450Hz so the opt does not need to be anything special.


I'm not experienced with tube amps, so don't know whether I want an opt with UL taps, what HT I should use, and whether to stick to a pair of EL34s, of use something like KT88, or KT120s.


Please point me to a suitable schematic


A pair of these mains transformers seems suitable. Power Transformer Guitar Amp Valve Tube 6L6 DIY Supply Push Pull FIRM Components | eBay


and have a 40vAC winding for biasing.


For opt Hammond 1650HA 6.6k 200ma

Hello,

I have an Harman Kardon power amplifier HK 770 but he have little problem.
This HK770 is buying by my father around 80's but around 97's have problem with it. The power don"t work correctly and out voltage at right chanel and burn the speaker . . . .
I take this for try to repair.

I have one diode burned and cut in two parts. Is the diode D420 (Ref HK : 5632-ERB12-02) Diode, ERB12-02.
When i look on internet is look like Silicon Rectifier Diode from Fuji Electric.
But actually this diode is discontinued.

HK Service manual on my dropbox : [wiki=https://www.dropbox.com/s/52j8lodmxysk9mu/hk-770_SM.pdf?dl=0]%[/wiki]
Datasheet find about the ERB12-02 : [wiki=https://www.dropbox.com/s/6oe1lt8ioyxanqk/erb1202.pdf?dl=0]%[/wiki]

Can you help me for find an equivalent for replace this parts !?
(I don't know what information is important on the datasheet for find replacement parts. Have many type of diode on the market : Diode Zener, TVS, Rectifier, Schottky etc.. and have only HK ref : ERB12-02).
I put picture of the diode on my dropbox :
Pic 1 : [wiki=https://www.dropbox.com/s/vygv24ue32bpgig/Diode_1.jpg?dl=0]%[/wiki]
Pic 2 : [wiki=https://www.dropbox.com/s/5fpj3424l1j5sj9/Diode_2.jpg?dl=0]%[/wiki]

Thanks for the help

Best regards

Hello,

For sale a battery spot welder good for 0.03mm to 0.15mm nickel strip welding.
It has very light use with less than 500 welds.

I bougth it from here: CGOLDENWALL JST Pulse Battery Spot Welder Small Hand-held Soldering Welding Machine Micro-Computer 18650 Battery Charger Power Bank 0.03-0.15mm (220V): Amazon.co.uk: DIY & Tools

Sold

Was wondering what the value or color code for circuit R152 please and thanks

Hello
I am looking for a Procced PDT-3 digital output board ore a bad PDT-3

New.

Bought from sachu888 in July 2019. Incl. PSU.

AD797 still in protective packaging.

$ 100 incl. shipping (newprice $ 145)

SOLD: Recently released Nelson Pass 2-way Jfet XO kit (PCB + Jfets + Bias resistors).
Have 2 units available, bought extras 'cos I usually make too many mistakes.
My 2-board 3-way XO build went together without a hitch, so am offering 2 spares, singly or together.
$75AU + postage each, or local pickup Melbourne.
Cash or bank deposit.

Good day all.

I have a set of Ruark Crusader 2s, and the mid-range on the one speaker is giving distortion. It does not sound like mechanical distortion, so I believe it could either be a dry soldering joint, or bad capacitor in the cross-over.

I have attempted to open the speaker up by removing the driver(s), so I can get to the crossover, but are unable to get the drivers off, even after removing the driver screws. Are these drivers also glued onto the box by any means?

Any advice welcome.

I would really like to restore the output to my preamp but am fully aware from reading some of the Cyrus related threads here that this is unlikely to be a DIY success. Not least because there are no circuit diagrams available even for experienced audio electronics engineers to access.

So my key question is whether there might be a straightforward diy check that could result in a safe diy repair?

The issue with my unit is that it powers up fine and does not go into error mode ie orange power light or shut down. The unit has never blown a fuse and I can't think of any time it has been subject to a mains surge.

The headphone part works without issue, full volume control and sounds really good. There is though no output from the pre-out into my Smartpower amp. I have tried both pre-out 1 and pre-out 2. Input is fine across CD, Aux etc and all provide undistorted sound to the headphone ouput.

I opened the unit and found that the two large blue 4700 uf 40v caps (c319 and c317) were showing 3500 uf so replaced. Also noticed that one of the 100 uf 50v caps was bulging so replaced both with Nichicon Muse equivalent. This is as shown on the attached pics.

I have closely inspected the traces under the board using a magnifier and can see nothing that looks broken.

Those who are familiar with Cyrus will know that this is not a supported unit and even when it was there was a whopping £300 plus postage charge which is far more than it is worth.

I am really reluctant to bin this but before reaching that conclusion thought I should run this past the highly knowledgeable members on this forum. If you are able to help that would be welcomed and might result in one less bit of landfill.

Initial internal photos attached for reference.

I just bought a Linn Karik and a Linn Kairn for spares or repair. Both were dead or showed very little life, I paid £120 for the two with remotes.

The Karik was completely dead and showed no life, it had a silver slimline Brilliant supply in it that a HiFi shop had tried to fix but failed. Using a MM there seems to be nothing out of that Brilliant.

The Kairn would only show the green LED, dimly. It also has the silver slimline Brilliant in it and that showed life on the MM.

I swapped the Brilliant from the Kairn into the Karik and the Karik now works fine 🙂

The "repair" on the other Brilliant is Sub Optimal as in there are at least two capacitors that were loose and on one of the large capacitors the solder pad has come away from the underside of the board. Am I right in thinking that the only connection to those capacitors is on the upper non pad side? If so I will attempt a repair of the pad.

However that still leaves me with the Kairn. This does not seem to be a PSU issue as the PSU originally in it is working fine in the Karik.
(Unless the Karik does not use all the Rails from the Brilliant?)

I have had a quick look at the main board for obvious Caps damage and the like and I cannot see anything. Any advice on what usually goes wrong on these?

However, when I took off the front I could see that the battery is corroded but I cannot see much damage from corrosion on the PCB and have tested out the lines I can see with potential damage and they seem OK. One SM Capacitor is hard to read but that could be because it is in circuit(?)

Any ideas on what to look for?

The white is the damaged tracks but they are showing continuity. Purple is the capacitor I cannot reliably/at all read. I have removed the battery in this pic.


Corrosion/Leaking Battery

I only own only four items using tubes so no frequent need of a tube tester.

Yesterday, I spotted a local ad for a Sencore TC-114 "Mighty Mite" for $50 snd picked it up. No tube chart included but I downloaded a copy.

One tube that I would have occasion to test are 6AU7's and the chart explains that....

...."for (their) tube tester models without a socket #13 a 6EU7 tube inserts into socket #3 with a jumper wire between pin 5 & pin 1".

This TC-114 is a model without a socket #13. Would the accepted method mearly be to wrap a thin, non-insulated wire around those tube pins prior to insertion or something more elaborate?

Took me 5 years to finally get around and do this. Quite happy with the build so far, will post more later once all is wired and connected, have a few different screw on CDs to try as well will be fun. Not sure how I will paint them. Suggestions?

I was dismayed to discover one of the tweeters silent on these speakers i have loved for 20 years!
Checked output at the crossover ok, found the tweeter to read about 1K, so unfortunately not broken at the leadouts where a repair can be done. The other reads about 8R. I play loud, but not to have overloaded, but maybe so? I can see the ferrofluid still looking wet in the gap.
Has anyone been through this and where to get a pair of tweets to suit, any ideas most welcome!

I have an old ACI Titan II sub that was making a very loud buzzing sound. Woke me up in the middle of the night. I put my hand on the speaker and it was loose. Not the screws that hold the casing but the cone with the rubber surround became detached from the casing? I turned over the sub and using some black silicone adhesive I re adhered the speaker to the casing. It moves well when pushing it in with my fingers. I also read the coil with an ohmmeter and it read 4.7 ohms. I'm assuming it's good?
I decided to pull out the amp and have a look at it. The amp has a big toroidal transformer and two Nichicon LQ (M) 6300uF 63 wv caps that both were a little bulged at the top. One a little more than the other. I decided to replace them with two Nichicon LS (M) 6300uF 63 v (not wv).

Getting the old caps out (snap-in and solder) was a little difficult but it seems I was able to do it without destroying the circuit traces as I have done in the past with other pieces of equipment. Put the new one's in and all I get is the unit powers on but the woofer does not respond to any signal.

Any ideas what is wrong? Could I have damaged something while replacing the caps or was something else damaged when the woofer became detached and was making that loud buzz for I don't know how long until it woke me up?

I'd appreciate any help. I'd hate to have to get rid of it when it may be just a simple fix.

Thanks, Nick

ive got some toroidal 24v 200va dual windings

ive got 20 of them could not throw them away..
i have some elektronic knowledge.
i want to build power suply for an amplifier.


ive been looking at

13.8V 20A linear power supply


i like the design but i vant higher voltage. up to 40v

can someone help me with this?




and can i put transformers in parallel and series for higher voltage and va?

I used 3 way speakers Jensen with 12" bass. I changed it to 12" full range Electrovoice /92 dB, 30-13000 Hz/. I disconnected middle. Sound is cool, better some expensive speakers. Its very easy to build. I use with my DIY SE 2A3 RCA and Im very happy! /40 $ for towers and 200 $ for 2 El.-Voice/.

I found it really unfair that a very interesting thread on BJT and FET preamps was closed because the original creator personally thought it was taking a direction he didn't like or was interested in. The thread was this:

https://www.diyaudio.com/forums/analogue-source/357649-fet-vs-bjt-input-phono-preamp-new-post.html

I didn't think the original thread creator could ask moderators to close a thread because of an opinion. If that is the case, then it is wrong, it should be changed.

A thread does not belong to anyone, and if things started to go the direction they went, incorporating in that case a very important element to the equation, which was cartridge load, it was because the whole system of a RIAA preamp, could only be considered complete when the cartridge is included.

In that case because of what the simulations, LTSpice or any other, that I think were brought in to the action. Other participants, like Marcel vdG and Hans Polak, added their own information, and warnings, about cart and preamp interface. Hans did start showing some LTSpic sims.

I disagree completely that the suggested thread was the one to discuss the interface beween a cart and a RIAA preamp

https://www.diyaudio.com/forums/analogue-source/303389-mechanical-resonance-mms.html

The OTs claim arguing why the thread should be closed is completely wrong and does not sustain itself. His arguments are not valid and do not apply to the rules of this forum.

What should have happened is a warning to his behavior, instead of closing the thread.

This may be out of place here. If so, I apologize.
I've only owned one tube amp and quite new to this.

Basically the question is should I spend more money on output tubes or would I benefit by getting a more powerful rectifier - if I am phrasing that correctly?

I've had my ST120 for a couple years and wildly pleased with it.
The other day I had a 6550WE red plate. After a bit of reading it appears I need to replace the 10ohm 2w resistor and I intend to replace the one bad tube with four new ones because, WHY NOT?

I have never "tube rolled" so I am going to lean on the greater knowledge of this group.

I imagine speakers and music should be considered when "rolling tubes"? It's all a sonic relationship.

My system
Preamp: NAD C658 running Dirac Live
Speakers: Goldenear Triton Five
Subs: 12" sealed cabinets x2 powered by a Peavey CS800x (temporary power)
Music: Mostly Tidal via Roon though have Pioneer Elite PD-65 cd player and an AT LP120 turntable.
Artists: Tord Gustavsen Trio, Pink Floyd, Taylor Swift, Nora Jones, Lyle Lovett, Aurora, Beck - if it has imaging for days and sonically interesting, I'll listen to it.
What are my goals: IMAGING & TONAL BALANCE.

I've spent years and years trying to setup a system that is balanced and the speakers disappear in the room. I finally have it; Tord Gustavsen Trio are 10' through the wall, Yello's Planet Da Da (flamboyant mix) has sound seemingly coming from behind me, and that low bass in Boz Skaggs "Thanks to you" rumbles my underside.

As of now the ST120 is delivering very little bass due to the 70hz crossover I set by Dirac to integrate my subs. I have, at times, disabled the subs and driven the Tritons full range but only for a few minutes at a time. The bass output is impressive, the speakers and amp, but I have not done so at length.

In the future, however, with "Dirac Live with Bass Control" I'll have the option of delivering full range to the Triton Five's and Dirac will integrate the subs seamlessly. So, in the future the ST120 will be delivering full range output.

I could swing a set of GL KT88's, or a set of 6550WE's and a GZ33 without much concern but, I'm not sure what the benefits of either decision would be? I'm not even sure how a rectifier can affect the sound - from what I gather it has to do with headroom.

I plan on ordering parts on Tuesday, hopefully I will have some help from you folks by then.

Hi Everyone,
My old Bose Wave Radio, Model AWR1- 1W, recently stopped working.
At first it wouldn't power up at all. I got hold of the service manual and guessed, correctly, that a likely cause was the R6 resistor. I replaced it and that fixed the power up issue but it remains with no sound. All the displays are OK - stations, volume, clock etc. just no sound.
If you know how to fix or troubleshoot this problem I would appreciate hearing from you.
I've just joined diyaudio on a friend's suggestion. Also checked previous posts and haven't found any relevant info.

thank you.

Hello all,

Built this amp years ago and sadly need to let it go to next owner. The chassis is a monster DIY effort from a fellow DIY'er here on this site. The chassis is a very nice crafted Aleph X design with monster heat sinks

The amp is a Aleph 5 from Brian at Chipamp.com. The PS tranny is a quality Piltron, and has four 56kuf caps.

The unit get nice and toasty and runs full out bias with the set resistor (R19) pulled. The power supply has 140F switches on the sinks. Currently have only Balanced inputs, but SE RCAs are back there - more pics forth coming...

I do not want to ship as I have NOT been having good luck with shipping lately (send and receiving)

Also have a circular Aleph X Meter (cheapie from ebay) that needs the center holes reamed to be inserted.

So local pickup - West sub of Chicago... $650

Looking for a functional CDM 4/19 drive or laser assembly or a stranded cd player that has that drive.
Thanks.

I know that there are a few threads on this DLM4500. But I am stuck on this amplifier and I need help. All I need is the small daughter card on the DLM 4500. The version I have will not fit a lm319 and tl072. Can anybody help me on where to find just the daughter card or help me with the PDFs so I can make my own daughter card that fits an LM319 and TL 072. I'm working on a very sentimental amplifier and I really don't want to shelf it. I have called dozens of places to see if they had a DLM 4500 and they are not very helpful. It seems like we are community sometimes but other times nobody wants to help in up-and-comer. I'm just learning and basically self-taught but I love working on amplifiers and I love the whole car audio community. Thanks, Amp Gutz

I'm looking for a 200Mhz 2 ch oscilloscope.... at the moment I'm looking at the Rigol DS2202A or E version and the Siglant SDS2000X-E.

Which would you go for.... or any other for that matter?

Dave

I am using a phono amp with a grounded grid first stage. It has a bad habit of picking noise up from other things plugged into the same circuit. It seems to usually be from any switching power supply on the same power supply. The same phono amp will make no noise in a different system. My questions:

1. Where is the noise getting into the amp
2. What can I do to fix it?

I have used powerline cleaners with no reults.

I've used 2 of these in series in humbucker arrangement for DHTs like 26 and 01A. I no longer use these tubes, more like medium size drivers with 16mA current.

Spec is 8mA, 150H, 3700R.

So before I build up something with two of these in parallel, how is it likely they'll function? I should get 16mA, 1850R, 75H. But what of the doubled capacitance? I don't have measuring equipment to check the frequency response, so can somebody hazard a guess at the results - maybe a loss of treble?

Ok... I'm doing some repairs and I'm having trouble finding a data sheet for this IC and thought maybe someone here might have seen this before. It appears to be distributing a clock signal of ~11.2896MHz to four AK4524 Audio codecs... Here's a pic.



The markings as far as I can tell are as follows:

MK70-1
231120A
0240CA

If I have the orientation correct then the output on pin 6 is going through the 33ohm resistor and then to the four AK4524 codecs...

I've tried Google and distributor/manufacturer websites, but came up empty. Does anyone have any idea what this is and what the pin out is?

think my pdr509 has a generic two pin power cord. I unplugged the cord from the unit.
Does it matter how it is put back in - ie for hot/neutral orientation?

Hi to everyone...

A few days ago I took on the task of rescue my old Nakamichi 700 II (1973-79) and the first thing I come across is a lack of 12 Volt output from the power supply PCB, the voltage It is not stable and varies randomly to such a degree that in the multiple measurements I made I registered 0. 4.5, 9.7,12.5, 13.2 and even 14.6 Vol. All of the above once you have tested the output of the corresponding winding in the transformer and checking that it is correct . In fact, the outputs that feed the vumeter bulbs are correct and they turn on when current is applied to the equipment.
I am not a scholar on the subject, I checked the 8 main components of the 12vol stage, the rectifier package, the two transistors, the capacitors and the two resistors but still I cannot find the origin of the problem perhaps due to my inexperience in the subject of checks on components.
I am very grateful for the help of a good Samaritan who enlightened me about it and guided me to the right path to solve this little problem.

Please see attached images and sorry to google for the bad translation

This amp uses IRFP064N with 47 ohm gate resistors .

Does anyone know the value of the pull down resistors ?

1

Some weeks ago, I received this miniature FM transmitter:



I didn't order it, and I didn't discuss the subject with other members.

A number of members have my private address, but nobody sent me an explanation.
I sometimes order goods from Banggood, but I didn't order anything for quite a time, and I never ordered this.

I do not know what I am supposed to do with this module. Test it? What parameters?

Hi,

Would someone be kind enough to let me know if they have experience with the model described below, and where it sits within the 2700 line up? The 2700-series has a myriad of options and I'm no expert on identifying a desirable model from one that is less so.

I have tried the 2722 with its oscillator routed to a UPV. True enough, the AP oscillator has around 2dB lower THD+N @ 1KHz than the UPV-B1 oscillator (usually gives -113dB THD+N, whereas AP nudges -115dB @ 2V RMS). I guess I'd need an AP555 to work out whether the analyser section of the 2722 or UPV is better.

I have seen people claim to have calibrated their 2722s themselves... Is this possible if you have another analyser (namely a UPV-B1-B3)?

Out of interest, what would be a ballpark price to ask for this analyser? I see them for stupid money on Ebay, but am fully aware that this is a false reality and real world prices are lower. If calibration is around £1,500-2000, is it worth doing it in order to sell it?

Thank you in advance!

This is taken from running the self-test routine:

Year of manufacture 2001
Model number: 2722-96K

IMD Option CHECKS
11/12/19 16:16:54 **********************************************
11/12/19 16:16:54
11/12/19 16:16:54 IMD option is not present in this instrument. Checks aborted.
11/12/19 16:16:54
11/12/19 16:16:54 **********************************************
11/12/19 16:16:54 BUR Option CHECKS
11/12/19 16:16:54 **********************************************
11/12/19 16:16:54
11/12/19 16:17:00 BUR option is not present in this instrument. Checks aborted.
11/12/19 16:17:00
11/12/19 16:17:00 **********************************************
11/12/19 16:17:00 WFA Option CHECKS
11/12/19 16:17:00 **********************************************
11/12/19 16:17:00
11/12/19 16:17:00 WFA option is not present in this instrument. Checks aborted.
11/12/19 16:17:00
11/12/19 16:17:00 **********************************************
11/12/19 16:17:00 AES17 Lowpass Filter Option CHECKS
11/12/19 16:17:00 **********************************************
11/12/19 16:17:00
11/12/19 16:17:00 AES17 Filter option is not present in this instrument. Checks aborted.

A few years ago I repaired (changed the foam wings) some Technics SB-1950 cabinets.
I had never seen anything like it.... 😱
Can someone explain what is the theory behind the use of this terry cloth stapled inside?
The cloth divides the inner compartment in two, so the tuning tube is tuned for the upper or lower volume ?
Or for the total volume, because it is the same as putting a sock inside the duct, the air will pass anyway?
Opinions ? 🙂

i have made a magnetizer for charging loudspeaker ferrites. It is working well at 1500vdc. Currently I am using a mechanical switch to discharge capacitors into the coil for magnetization.

Now i want to implement SSR relays or thyristors but i don't understand its work and if I want to buy ready made ones then there is nothing available above 1200vdc. Also the guy who sells it says it cannot be used in series.

Any guidance can be very helpful. sorry for my English.

Hi there,

I bought a defective sony cdp-x33es, the problem with the player is that the right channel is distorted.
After changing all the red Duorex II caps (which were almost all leaking) for Nichicon Finegold caps the problem is still the same, but if i let the player play for 3 minutes the right channel is suddenly good again...

Any idea what else could cause this problem?

thx!

Rubbereend

Is there any solid proof that a real world moving magnet cartridge behaves better with a fet input than with a BJT input?

I was always impressed with the sound and looks of speakers from the 70s.

They were effective, simple, easy on the eye and had a logical driver placement for 3 way systems with larger bass drivers than what we typically see today. Speakers of this era also had a lot more enjoyable "body" most likely due to the larger bass drivers and wider baffles, compared to today's narrow floor standing towers which I never liked. Which is one of many reasons I'm into DIY, I want to create similar sounding speakers but with more up to date technology and driver quality.

My first pair of speakers as kid was an inherited SEAS/Dynaco A25 DIY kit of some variant. Later I was playing around with Pioneer CS-R700. Both I really enjoyed. Since then Ive made many different types of budget DIY projects, last few including Fane full range PA drivers and Eminence coaxials. Now I'm trying to design some similar looking speakers from the 70s era and I'm playing around with baffle sizes and driver selection, and the use of the golden ratio and Fibonacci sequence numbers as it seems speakers close to this baffle ratio is what I seem to enjoy, looking at the sizing specs of those good 70s designs, I can name a bunch but you get the idea.

I want to go up a size though to fill a larger basement with high efficiency dynamics and will for the most part use PA drivers. Im already playing around with some 12" coax designs but will go further in my next project once I get the experience with crossovers and box woodwork finishing as my older project never looked very good, and Ive always struggled with crossover due to lacking measuring tools and know-how so I need to step up the game before going into this big project.

The current idea however, is a big speaker system based on the drawing attached 1300x800mm front baffle, using the first few Fibonacci numbers to determine the driver placements, in this case a 4 way system with active sub section. I will most likely build the sub section as a stand alone 800x800 box but in the drawing shown as one speaker. I may also just drop the whole sub section and go with 800x500 3-way system as it may be more than enough for my use. I'm also going to make a smaller 10" three way system for a different room using the same layout, might make this first for practise.

Any one else using the golden ratio of phi for designing their speakers?

I am interested in starting a Dynaudio Myrage project. I have scans but they are not good enough to read the cabinet dimensions. There have been some links around for Dynaudio plans, but the ones I have found are broken. Does anyone have a good scan of the plans you would share with me? Thank you very much.

hello
I have to replace this old woofer
Eminence Legend 875 8" Guitar Speaker 4 Ohm

anyone has it?
I asked eminence, they said they could built as a custom minimum order of 100 pieces. I need only one.
In any case, which one match as a replacement?
I also will look elsewhere to decrease the weight.
best

Hello everyone,
Im pretty new to amplifiers and all this, but some time ago I wanted to make a police siren amplifier (only the electronic air horn part) for my car. So I researched a little bit on the internet and was able to find schematics of some 80s and 90s siren amplifiers. With these I was able to recreate the exact air horn sound I wanted but now that I have the sound generated I dont know how to amplify it.
The Airhorn sound is a square wave of around 500 Hz and 10 Vpp.
I have an 100W 11Ohm and two 70W 8Ohm siren speakers.
Here is the schematic of the amplifier that is used by the original siren.



The design uses some kind of push pull amplifier which i cant get my head around.

My question now is if anyone can help me understand this amplifier or recommend me other designs that could work in a car, like a Class D amplifier maybe.

Thank you all

Best Regards

I am using a pair of CS1 on my test bench as I build and modify a JLH Class A amplifier. They are advertised as 8 Ohm impedance however I suspect they might actually be lower.

Does anyone know what the impedance is of the Polk CS1 and R50 (beyond the claimed specs)? Based upon any measurements? Or use with Class A amplifiers?

I don't have anything setup to measure speaker impedance, however just my voltmeter on the back terminals of the CS1 reads close to 4 Ohms.

Polk Audio CS1 (Black) Center channel speaker at Crutchfield

Polk Audio R50 Tower speakers at Crutchfield

Today marks the 20th anniversary of the first post in our current forum.

In that time the forum has gone from very humble beginnings to the largest do-it-yourself audio community on the web. Just a few weeks ago we surpassed half a million registered members and 6,000,000 posts.

Thanks to our wonderful moderation team, and the incredibly friendly and generous membership, diyAudio has earned a reputation as one of the most friendly and rewarding audio communities on the net today.

There's no great fanfare for today's marking of time. We're busy working on what's coming next and it's going to be great.

The store has converted many lurkers into builders, but the popularity of the site, the store, and more recently the store's kit offerings combined has meant we've had to take a little time out to get things ready for the site's next era. In the coming months diyAudio will have a few more hands on deck to help things progress smoothly out of its teenage years. The result will be worth it, and once that happens we'll be be having a considerable celebration 🙂

Here's to the last 20 years, and to the next 20!

Jason

The spec's seem the same. The SOA is stated in datasheet as being higher on the x96 but the curves and numbers don't really corroborate.

The functionality curves are somewhat different, and to my uneducated eye, look more uniform/desirable on the x94 devices.

The MJ21196's are cheaper.

So, is there any general preference or advantage of one over the other for use as output transistors?

Any advice here?

..Todd

Hello,

A short question for those who know more about recently released components on the audio chip market...

Having had some interest in MOSFET amplifiers, I noticed that Linear Technology already for some years has marketed the LT1166 unity gain MOSFET bias regulator. There are some posts on the forum from 2017 about this. To make things easier (and more compact with building, and possibly retaining the low THD-N) a low THD voltage amp needs to be added.

Are there any similar chips as the LT1166 with variable gain on the market?

Martin

After owning a pair of Heybrook Sextet Mk 1Vs for over 20 years I decide it was time to externalise the passive x/overs.

There was a thread from the old WAD forum, not much info on what the internals were like but a definite endorsement about doubling the filler material for the bass chamber.

I have some blanket type material used to protect furniture when moving. It's made of various wool, man made fibres etc. It seems very suitable for the purpose of applying to the walls of the bass chamber.

The Sextets have two chambers - one for mids and the Tonigen tweeter and one for the bass. The construction of the bass chamber is about 2/3rds of the total cabinet and consists of a bracing bar half way leaving about 50cm on either side of the bracing bar for the sound pressure to enter the two ports before exiting.

Should I use this material on the upper section of the chamber or the bottom section. I will use fixative to hold the material in place.

Also should I 'cover' all 4 walls?When I removed the internal x/over I replaced the empty space with plywood to fill this space in effect creating a solid wall.

If the rec. is too use this in the bottom half of the chamber I can remove this plate to access the bottom half should the material prove to be a negative. However the top half will mean removing the SEAS woofer to access the top half of the chamber.

I have been reading up speaker desgin and DCR seem very interesting to build, but I dont understand why most of the desginer settle their mid bass chamber at the bottom of the speaker.
Take Merlin for example
Dayton RS-180 Double Chamber Reflex (DCR)

for better mid bass sounding shouldnt mid bass chamber should be located at the top of the cabinet. So the speaker structure should be upside down except the bass unit.
So our speaker arrangment would have Ported (mid bass), mid range driver , tweeter and Ported bass at the very bottom near the floor .
And for a tighter bass control,is it possible to replace the ported mid bass with passive radiator or should it be better to use dual pasive radiator replacing ported bass instead ?

The last question is, the ported Woofer, Mid, Tweeter arrangment might cause a headache in the crossover desgin, so it possible fix this problem by making a L shaped vent exiting port firing above the bass the port or simply creating a L shape or quadrangle mid-bass chamber which the port is firing back of the speaker but above the mid bass port.


For a reference driver to desgin lets assume we are desgining around the mid range driver is MW16p or MR16p

PS Sorry about my engish and not having photoshop to show my idea, but it seems the desgin of the final speaker arrangmet will be going to looks like audio physic tempo plus

EDIT: SOLD

One pair of used Tannoy 8" type 2046 Dual Concentric drivers, in good working condition.
Great for DIY projects, or replacements for your Tannoy System 800 / 800a studio monitors.
If you're going the DIY route, I can include the factory crossovers.

$300 plus $20 flat rate shipping within lower 48

Will be expertly packed, shipped insured and with tracking via UPS Ground.
Thank you for looking

Hi all,

I've been away from this forum for 10 years but I'm finally back at a point where I can play with DIY audio again 😀.
I want to build some small speakers to wall mount in my new covid home office, bass extension isn't particularly important I just want something better than the speakers in my laptop for general music listening.

From reading various threads the Alpair 5.3 looks like a good driver and it's available easily where I am in the UK. I've found the following compact designs for it:

• Woden BloodHound http://wodendesign.com/downloads/Woden-BabyLabs-241018.pdf
• Sub compact vented desktop https://www.kjfaudio.com/wp-content/uploads/2020/07/Alpair-5.3-sub-compant-vented-box-metric.png

I wanted to ask if anyone had an opinion on those designs or if there were another better design I may have missed?

Thanks

I already put the PCB design in the thread `Bridgle or Parallel" where I had put the circuit design sometime back. But as I need suggestions and corrections for the circuit and the pcb design, I thought I should start a new thread with a different title.

The links are:

Cirsuit. http://www.diyaudio.com/forums/attachment.php?s=&postid=529675&stamp=1102598305

Power Supply.

http://www.diyaudio.com/forums/attachment.php?s=&postid=537485&stamp=1103622043

A .png file of the PCB.

http://www.diyaudio.com/forums/attachment.php?s=&postid=971042&stamp=1154059199

Top side of the board:

http://www.diyaudio.com/forums/attachment.php?s=&postid=971043&stamp=1154059264

Bottom side of the board:

http://www.diyaudio.com/forums/attachment.php?s=&postid=971044&stamp=1154059327

I will make the following changes in the circuit/pcb suggested by Gajanan.

1. move the parts away from the heat sink.
2. place several PTH in power line wherever it ocures.
3. take the outgnd from one of the filter capacitor.

I will also redesign the circuits around the regulators in the PS to meet the minimal load requirements.

If you see any more troubles or mistakes with the circuits or PCB please point out.

thanks
Roushon.

Good Evening everyone. I had to make a new post for these items for free and for sale.



1. Live Wire Cable Tester brand new in box for free. $20.00 for shipping. Gone.


2. Lepai Lp-168HA SuperBass Modded amp for free. Brand new in box with power supply. Asking $20 .00 for shipping. It has some ware on the side mounting holes due to being screwed down on a board but, never used. Brand new. Gone




3. Baxfx Products. Digital Sound level meter for free. I did use it for a few minutes to see if it worked and it does. I have the case and manual and wires. I am throwing in a little digital scale with manual with it. Brand new. For free. I'm asking $30.00 for shipping. Not available anymore.


4. The Lepai LP-168HA Normal amps for free with boxes and manuals. The amp have ware from being screwed into a board but, has never been use and I have both power supply's. I am asking $30.00 for shipping on these items. Gone.






Just pm me or e mail me at marchj313@gmail.com for questions or pictures. That is my pay pal account as well. I only ship to the 48 United States.
I am only using ups due to work hours and I go through my wife's work.. I don't get a discount. I tired to price the items right? Cheers Jeff

Amp will not power up .

Here is what I get on the 494

Pin 1:0.82
Pin 2:3.79
Pin 3:0.09
Pin 4:0.00
Pin 5:1.48
Pin 6:3.40
Pin 7:0.00
Pin 8:13.90
Pin 9:0.00
Pin 10:0.00
Pin 11:13.90
Pin 12:13.90
Pin 13:4.95
Pin 14:4.95
Pin 15:4.95
Pin 16:4.24

EU only, for sale 3e-audio tpa3255 last version + Meanwell LRS-200-36,
90 euros + shipping

I noticed that Nelson Pass has adapted the filters that are used in the Mini DSP used on the Linkwitz LX-Mini. He has developed an active filter that uses JFETS. I read that he used Micro-Cap that has an active filter designer built in.
I have bought a Mini DSP and eventually would like to transfer the filter characteristic over to an analogue active filter.
What are the steps needed to do this? Is there any reference material I can study to make this possible? I have an Electronics background, so I'm willing to give it a try. Any help appreciated. Thanks.

David.

Hi DIYers,

I have broken the stylus on my Clear Audio Concept MM cartridge. How do you remove the broken stylus and replace it with an AT stylus. Which AT stylus suits the Concept MM best. Thanks in advance.

Keith

This is an announcement of the LF01 discrete/hybrid module that uses a monolithic SOIC-8 single opamp, some BJTs and passives and plugs into a DIP-8 single-opamp socket. The intent is to bias the output stage of the opamp into Class-A, the discrete output stage into Class-A/AB and bypass the current limit of the monolithic opamp (more details will follow later).

Schematic, Layout and picture of a prototype with an LM318 installed - this is intended for the MyRef Rev C:

Hello fellow DIY-ers!

This is my first thread here on this forum abut the idea I have on this "stereo center speaker".

First of all I have zero knowledge on acoustics and zero experience building speaker enclosures so take it easy on me.

The idea is to have two speaker enclosures in a single unit and place it under my TV

I already have two Markaudio CHR70.3 drivers on hand and also a class D Bluetooth amplifier with line in and a matching power supply that will be placed in the middle compartment of the unit.

All the measurements on the drawing are in millimeters

Hi,

i'm selling my ACA amplifier as it is currently only standing around.

I build it with better quality parts for the caps an the resistors. Here are the parts i used:

C1: 3300 uF, 50V; Nichicon KG series "Gold Tune"
C2: 1000 uF, 16V; Nichicon
C4/C4: 10 uF, 50V; Nichicon
Dale CMF55 Resistors
50k Alps Poti

It's not the original case from the ACA-Kit on this site. I used another one with the option for a poti. Actualy there is a 50k Alps Poti installed.
In the back there is also a 230V plug, but it is not used.
I sell it with the 24V(5A) power supply from MeanWell, which is also a part of the original ACA-Kit

If you have any questions just ask 🙂

Price 250€ + shipping (i live in germany)


Regards
Nico

Not sure if this was asked before saw a few threads on this topic but there were not in my exact use case.

I have a kitchen streamer based on a Pi and the standard 7 inch screen. Until now I used the standard touchscreen With a pi 4. Have a little usb dac and than a pair of active speakers.

Trouble started when I decided to get a DAC hat. I actually got an Aliexpress ak4493 for 45 euros. Pretty pleased with sound actually. Obviously the case I had no longer works. As I want a single box solution I am looking for a suitable case. The Audiophonics Raspitouch one could have been a candidate but it’s out os stock. Any ideas? I don’t have the know how to build a case myself, was even thinking of 3D printing have no clue how to go about this. To clarify, just need to fit the touscreen the pi and the hat. want to keep this compact and happy to run this with standard 5v power.

Way back, 20+ years ago, I bought a pair of Babb full range speakers (I think the company was winding down at the tone, and they sold a load of stock - can't remember the details). Anyhow, I never used them but still have them in boxes. I have no data for them, nor designs. I think they're designed for dashboard of boats, so presumably infinite baffle or open baffle is alright.

Anyone got experience? Or measurements?

Cheers, hopefully.

Anyone have a recommended source for buying a small round VU meter? I want a more vintage analog needle look. Also anyone hook a VU meter up through speaker wires? Working on some OS MTM and would like to ad one to each.
Finishing up a Isetta as a present for friends new dental office.

Anyone have any experience with Mini LED projectors? I am about to buy one, this one seems good.

Mini HD 1080p LED Projector Home Cinema Theater Multimedia PC USB SD TV AV HDMI | eBay

400 lumens should be bright enough- at night

I have an old RCA WA-44C sine/square wave tone generator which has multiple tubes. I'd like to replace them, just because I think I should. The last time I turned the unit on was about 15 years ago! Now, with my speaker project, I need to use it again.

I know there are several places where I can buy tubes on the 'net, but I'd like to know which places (in the US) you folks have had good experience with in buying high quality new tubes.

Thank you very much!

Let's consider two different power supplies for a DC-10 KHz 4 channel single ended 18-bit DAC being used for a physics experiment. It will in the end feed a high impedance — the principal power draw is the quiescent load of the opamps, DACs, and MCU. For reference, 18-bits corresponds to 108.37 dB of SNR:

In one design I use an external power supply such as Blocked . Inside I use a high quality LDO. 1% pk-pk ripple from the datasheet is -20 dBV voltage, or -40 dB power relative to the supply, and then on top of that I can use a high end LDO such as the TI TPS7A4901 which features 70 dB PSRR, for a total of 110 dB... ideally. I place the brick outside the enclosure and add a ferrite to the DC line to fight common mode noise. Maybe I add some ferrites and pi filters inside the enclosure before the LDO to get the last bit of performance out. Given that the references of the DAC and the DAC itself have their own PSRR, I would imagine I'm in the clear.

In another design, I use a much larger chassis and an Acopian A5MT510 which outputs 5 volts and has 0.25 mV ripple. That's -40 dBV or -80 (?!) dB power relative to the supply. I suppose I could add an LDO there and potentially under ideal circumstances beat 110 dB but 110 dB seems quite low, and I have to imagine I'd be limited by other things at this level.

My question is this... is there really any sense in buying a high end linear power supply outside of simplicity and reliability when you can get a decent switcher and pair it with an LDO and a little filtering and do essentially well enough? If this is true now, when in the history of electrical engineering did it become true and what was the reason?

Finally, is there a cheap and cheerful way to probe a power rail? I’m thinking I want a 50 ohm transmission line with DC blocking capacitor and front termination feeding into a low noise preamp like an SR560 or something like that. Maybe I should instead use a FET probe, but in the end I really have no qualms about loading the rail, as it’s a power rail!

Good afternoon everyone. I have noticed that I can sign on ,y lab top computer but not my android phone? Is There something going on? Is there a block in the forums sign in link? Please advise what my next step should be? Thanks Jeff


P.s. I stopped getting e mails as well? This happened a while ago?

Papa or anyone played with this yet?

It sounded wow blow me down.. On one commercial amp.. I squeal with excitement like a girl.

I have bought good second hand items many times in the past and tweaked them for better performance. As far as speakers go, that included Sonus Faber. Perfectly good commercial designs have compromises inherent in the design to reduce manufacturing costs.

Here are some examples of the modifications I did to the original Sonus Faber Grand Piano to make it sound better. A lot these mods can be applied to other speakers too if you decide to buy second hand and tweak. Some of these mods can be made reversible.

I stabilized the clip-on interface of the Seas 19TFF1 tweeter with a few drops of epoxy glue. Cleaned up the treble somewhat. Only reversible if you buy new tweeters from the Sonus Faber agent. The standard 19TFF1 won't do, because the originals have SF's logo on the face plate.

I isolated the tweeter from the pressure of the mid-woofer, ensuring that it operates in its own sealed chamber. Fortunately this was easy to to, since the tweeter did not protrude behind the thick front baffle. This resulted in significantly improved treble response with less fatigue. A stethoscope test with the tweeter disconnected led me towards this mod. This mod can be made reversible.

I soldered the cables directly to the driver terminals, removing the push-on lugs. It is funny that they use expensive gold plated terminals on the outside of the speaker and dubious connectors on the inside. Sounded more fluid. Not really reversible, because the woofer terminals are gold plated.

This speaker has a dedicated crossover compartment. I filled that with clean sand, giving better stability. With most decent speakers a worthwhile improvement can be had by removing the crossover from the cabinet and putting it in a separate enclosure, maybe damping it. 100% reversible.

I tuned one side panel per speaker to a different frequency by attaching small lead weights. The idea is that the side panel resonances would be less noticable if they are not coincident. Used a stethoscope again. Can be done 90% reversible.

I changed the tweeter attenuation from a series resistor to an L-pad. I did this because I believe the fundamental resonance of the 19TFF1 was audible although cleverly voiced into the design. The L-pad design made this resonance almost inaudible. The speaker was also too bright. This was also rectified with the L-pad. 100% reversible.

These tweeter isolation and panel tuning mods decreased the internal volume somewhat, but the bass alignment did not change significantly.

I now want to experiment with the cabinet lining material, because I want to reduce the tweeter output a little more, but I need to reduce a slight lower mid coloration before I can do that. If guys reading this have any suggestions, please respond here.

Last step would probably be to replace the Seas tweeter with something like a Hiquphon. And test out better caps in the crossover. It uses standard Philips MKP.

.

Dear All!
This is first time I designed acoustic system for monitoring purposes.
Speaker is Dayton rs100-8, 4". It can handle 30watt rms max, and 60 watts at peak.
Also it has very good frequency response curve (dunno how close real speaker is to that curve).

Here is calculation of frequency response in cabinet at zero degrees:


So, to achieve better results, I decided to involve passive filters to flatten FR.



Filters from left to right - Notch filter around 3,3khz, baffle step correction, Notch filter around 17khz.

So the problem I faced - which power rating components to choose in this circuit. Maximum power intended to use here - 20watts.
Does it mean that resistors must have 20watt rating (or better more), and inductors to be 2.5A plus?
I really don't want to have burning and smelling monitors 🙂
I would appreciate any constructive criticism. For example I'm not sure if impedance characteristics are good, also High end of FR has that spikes, and not drops smoothly. May it cause unwanted harmonics or something else? (I understand it is above hearing range 🙂 )