Since I get most parts to do it ! let's go..... anybody built this Double Barrel version 2.1A , bought the boards from Hong Kong at least 20 years ago., I ask just to be sure this version
is not a problematic one !

Working on rebuilding an NVA AP50 amplifier from scratch, I have a question about the output transistors. NVA is known to have used BDV64/65 and TIP142/147 darlington output transistors in these amps, driven by TIP31/32 transistors. Mine actually has a mix of these BDV / TIP output transistors. Whatever parts one has laying around I guess...

Would a pair of Sanken 2SB1560 / 2SD2390 darlingtons be drop-in replacements? This here thread from 2013 suggests they may be. I looked for spice models but couldn't find any. It looks like the maximum collector current of the BDV is 15A vs the TIP's 10A and the Sankens are 10A also. The Sanken's gain looks to be considerably higher. Internal construction too. The Sanken omits an internal resistor (and a protection diode?).





Here is the schematic:

A friend offered me a PCM2704 USB DAC board and I thought of potting the board into a nice enclosure. I shared the idea of potting, however he warned me that some ICs as this one could be sensitive from leftover solder rosin flux increasing the capacitance between high frequency traces, probably bringing malfunction to the circuit operation. Now, a potting compound would do the same, with a dielectric constant of at least 3.

What do you think?

Hi everyone.

I,m running Volumio on a raspberry Pi, USB out to a MiniDSP2X4HD configured as 2.1.

Does any one know if there a way to get automatic loudness function or dynamic EQ or something to compensate för lack of bass in low volume with this setup?

FusionDSP is available on Volumio however it doesn't support 2.1 configuration.
MiniDSP does not have automatic Loudness function either as far as I can read. ( can have several fixed settings though )

Any ideas?

Thanxs
JZ

My tweeter stopped working, when I press on it lightly from some corners, it turns back on. I suspect the tweeter voice coil is broken.




I removed the rear small panel, and have access to the single screw at the back of the magnet. However, I suspect I need to remove the front plate of this speaker... Any idea how?



This diagram from the same series of speakers (C7), but the construction is relatively the same... Is it glued in place? Do I pry it off at the edge?



Also what is the appropriate coil replacement here? I see 19mm/0.75inch Aluminium, 8ohm... I see some options on aliexpress on ebay (titanium and aluminium)... would appreciate any help! I'm total newbie to this type of stuff but have a background with electronics/electrical components repair.

Hello from the Netherlands!
My name is Jan and I am living in Nieuwe Tonge, on the beautiful island Goeree-Overflakkee. My vintage collection consists of a Marantz SC-80 in combination with a SM-80 amp. An Akai AP-206 turntable and a Marantz CD-60 cd-player complete the set. Speakers are KEF C7.

Second set is a Denon PMA-725R amplifier, an Akai ATT05U turntable and a Sony CDP-195 cd-player and a pair of JBL TLX5000 speakers.

I hope to find (and give) usefull information on this forum to keep the old stuff alive!

Best regards,

Jan

Greetings from Arizona! Building the Open Source Monkey Coffin Loudspeaker project with a few buddies. Have otherwise followed the site for years.

dear all,

this oven was tested for functionality when it was bought around 3 years ago. but the project didnt move on
and such it is sitting idle. So now comes the decision for selling as it was never used.

maximum board size is 180 x 235 mm which is cool.

will sell to EU only, asking 130 euro+shipping.
shipping will depend on destination obviously i estimate for most destinations between 25-30 euro.

thx for looking!

Hi. I am a 62-year-old guy in Sweden doing DIY electronics in my teenage. Picked up my old Marantz TT120 from the cellar and fixed it yesterday. Found a lot of fun discussions here and want to join.

Hi all,

Hopefully there are some op-amp experts here. I am making a mic. preamp board and will be using the PGA2505 IC for amplifying the input signal.

However, I am trying to decide on an op-amp for various audio roles: audio peak-detect circuit, low-pass filtering, buffering, and a balanced line driver. I could use different op-amps but prefer to consolidate to one.

I have +-5V rails available so will be using dual-supply and obviously rail-to-rail input and output is a necessity.

Initially I was going to use the NE5532 but saw the TI recommends the TLV9362 as a replacement.

Searching TI audio op-amp sections revealed the LME49721.

Then there are more general purpose options: AD8542 and TLV9002

Here are some stats.

• I like the TLV9002 for the cost but is 30 nV√Hz acceptable for audio?
  • Maybe for peak-detect this would be OK, but probably not for anything in the signal path?
• Is there a compelling reason to pick the TLV9362 over the LME49721 (other than cost)?

I’m hoping that someone might be able to help me out with a schematic of this unit or similar, or maybe walk me through some suggestions. I’m getting no standby action from this receiver at all. It’s completely dead at plug in. No relay, no display, no standby to be seen at all.

Thank you,
Dan

I'm a retired console driver who freelanced for 20 years and then owned his own studio for another 20. While not something I will actually do myself, I have become interested (fascinated?) by the myriad audio construction, restoration and repair projects undertaken by various folks. I hope to follow some of your adventures here.

Barely used, mint, with box. New price is $55-60. Asking $45, plus $10 shipping.

Hi,

Essentially I am trying to work out the best / loudest / safest way to wire up the following system for DJing.

I have some new (second hand) PA with the following speakers. I have been tinkering with the Bass and 600 watt full range cabs using the crossover, but I am beginning to think that it loses some of the frequency range on the full range cabs and loses some volume... broadness of the sound.

We have added the two ST 15 350 watt this weekend and are thinking about the best way to set this lot up so it give the best / loudest full range sound but doesn't blow the cones!

I think the Peavey cabs are designed to be daisy chained as they all have the Speakon In / Out connectors. I think I read somewhere that the Pro system has some wiring inside the cabs that does not change the ohms..? But I'm not sure / cannot find it again.

I have a pair of Peavey Pro Sub 15" Bass Bins 600 watt 4 ohms
A pair of Peavey Pro 15" 600 watt program 4 ohms (full range with horns) - so I imagine passive crossover inside
A pair of Peavey ST 15 350 watt program 8 ohms (full range with horns) - so I imagine passive crossover inside

Amp 1: Peavey 2600 Amp
Amp 2: Kam 2000 Amp

Super X 2300 Behringer Crossover

Any advice appreciated.

Thanks - Nick

If I lay a 16-ohm resistor across the terminals of a 16-ohm woofer, can I incorporate it into a 3-way system, the rest of which is 8-ohm?

Heat sink profile, 160x40mm, 10mm base, like Fischer SK85/100/SA but 118mm long, black anodized,, ~1.1kg/pcs, 2pcs avaiable
As above but 125mm long, ~1.2kg/pcs, 9pcs avaiable
The anodized profiles are ca 0.6K/W
Same profile but not anodized and 500mm long, ~4.7kg/pcs, 3pcs avaiable
Asking price for anodized 18€/kg, not anodized blank alu 14€/kg
20% discount above a total of 10-20kg

I was not sure if it is aloud to attach the pdf from Fischer so i deleted it, please google for it to get the details
Tnx for watching, offers are welcome

Hello everyone.

My name is Simon.

I have build a stereo speaker set in the past and am looking to revive this hobby.

The speakers I build are flawwed in a few ways so I hope to share what not to do, as well as learn from you how to improve them.

Hi, I'm a Spanish guy who is in love with his DIY open speaker and wants to learn and improve his system with the immense information on this site. I already did it by reading some posts. I have a question but I'll save it for my next post. Greetings to everyone and thanks for having me.

Thanks for allowing me to join this group. I see there are knowledgeable members and it will be awesome to get to interact with Andy Szabo the @AcoustatAnswerMan who was one of the designers!

Hello, I'm new here, I am an audio enthusiast who just built my first point-to-point power amplifier (Analog Ethos AE1) and I love it! I also have a couple websites, Deep Groove Mono and RVG Legacy. I would love to do some more DIY in the future!

Hey all.

I've been searching for symbol and footprint for an LSK389B (TO-71), and I'm just finding noise and nothing online. Does anyone here have something in their libraries for KiCAD?

Much appreciated.

Hi - thanks for letting me sign up. I want to ask a question about PA set up using a crossover and daisy chaining.

I'm an electronics hobbiest.
I purchased a used Kicker CX660.5 that was supposed to work but did not.

The red protect light comes on and stays on when power is applied without the remote wire connected.

I would like to attempt repair. Any help available? Schematics?

Thank you

Hello all,

I use REW and rephase FIR filters for my room correction. I had exported from REW a L and R vector averaged measurments for 6 ea. positions arounf my normal sitting position. All time aligned of course. In rephase there is a significant difference in phase with the L measurment showing a -720 degree shift after 1000 hz to 20000 hz.

When I bring in the single centre position measurments from L and R, the phase matches fairly closely.

I infer that the averaging process is changing the phase, making it impossible to do phase alignment. And there doesnt seem to be a way to merge the phase from the single measurements into the gain measurement of the averaged responses. If even that makes sense. Has anyone run into this? Otherwise I would seem to have to go back to single measurents if I want to adjust phase.

Cheers,
T

Hello, my name is Gabriel Barbosa I'm an electrical engineer working in a junior college school in Brazil as a electronics lab technician. I'm interested in tube audio, vintage audio devices such as 8 track tubes, record players and guitar amps. I joined the forum as I want to build some tube projects and get the help from members.

Hello, the question I am asking has been asked by many on this forum, but not in the right perspective, I think.
But here goes. Why is a critically damped Q factor bad? Psychoacoustically.

In my opinion, if critical damping is between overdamped and underdamped, then this is the ideal Q factor for most applications.

But it seems that psychoacoustically some people don't like it, saying that it sounds weak, thin and that there is not much advantage in tuning a speaker with this Q factor.
Others say that it has better transients and that the speaker has better time domain with this Q factor.
There are also those who agree that a change in Q factor, for example: from 0.707 to 0.500, will not be audible, because the acoustics of the room dominate most of the low frequency sound [120hz or less].

Really, this question is about how a critically damped Q factor [0.5] can affect the sound of a speaker both in measurements, such as impulse response and step response, and psychoacoustically for people.

[Other]
For this question, the speakers can be of any type, for example: mid-rangers, subwoofers, full-rangers, etc.

Selling my 2nd pair of UTC LS-33 output transformers, used with Sony VFet 2SK82 with great success. 80% nickel core, triple shielded
SOLD shipped. US Domestic shipping only.






Price: 400$ shipped to mainland USA.

Came across some YouTube tutorials on how DIY usb cables:

Login to view embedded media Login to view embedded media
This video about mid-priced systems being improved by "higher end" USB cables:
Login to view embedded media
And this one about some very high-end "audiophile" USB cables:
Login to view embedded media
Not sure about USB. I just use the cheap "free" cables that came with my printer or scanner.
I have experimented a bit with shortening the cheap/free cables. Not sure about results.

In any case, building my own USB cables -- as the top two videos suggest -- seems like a cheap and easy way to improve sound from my PC.

Anyone out there with more experience or suggestions on this topic?

I am selling the following:
-1 Seas CA22RNY 8" coated paper cone high excursion low mass woofer. This unit is new without box. $60 + $20 shipping.

I have just finished CAD and CAM design for a bass module inspired by XRK's SLOB speaker. It is using 8 x 6.5" no name drivers which have similar specs. It will be made out of Paulownia glued planks, since it is actually cheaper, lighter and much stronger than MDF. The finish will be just oil, or maybe some not too dark stain, I yet have to try on some scraps.

It is intended to play below ca 400 Hz with a large horn with DCX464 on top of it (that one will be revealed later).

Tomorrow, I am getting the wood and hope to start cutting soon.

I have some NOS Tripath chips. these were provided to Audio Research when they were designing their Class-T amp. all brand new. No idea what they are worth. Open to offers. cash (paypal) is best but might be open to interesting trades. Dead amplifiers, reel to reel tapes, tubes, etc etc

All brand new, never used or soldered
4x 47uf/600v; $30 each
2x 100uf/550v; $40 each

Buyer will be responsible for shipping cost

AIM:

To design a family of small speakers with that BIG 3-WAY sound that I'm used to, with the aid of the Klippel NFS
Designed for High power handling / low distortion/ low power compression.

Midwoofers: Purifi eXtended x-max drivers.
Tweeters Scan-Speak, SEAS, SB Acoustics or Purifi (TBC)

Cabinets: 1/8, 1/4th, 1/2 or 1 cu foot.

Crossovers optimised for smooth in-room response, and phase coherent at typical listening distances.

Easy to construct for DIYers - use a tweeter you may already have, then build a cabinet you’re comfortable with. Some designs feature centred tweeters, others have offset tweeters. Other cabinets use full 1.5" round overs.

Easy to repair using readily available parts from Purifi and Scan-Speak, SB Acoustics etc.

Designed for free standing (>60cm from front wall ideal). Stretch goals- close to wall, against wall or desktop mounting (no ETA), passive crossovers (no ETA)


Danish Duo Micro. status- Active crossover complete!
Speaker dimensions ~10” x 5” x 8”
featuring Purifi PTT4.0X-04, SBA19mm soft dome tweeter. No waveguide. 1” round over for tweeter.











Danish Duo Mini status- Measurements complete
Dimensions- 12” x 8” x 8”
5.25" Purifi woofer.
-3dB extension 45Hz
Centred tweeter; no roundovers.





Danish Duo status- Active crossover completed!
PTT 6.5X04-NAA 6.5" aluminium cone midwoofer OR PTT 6.5X04-NFA 6.5" Fibre cone midwoofer
ScanSpeak D2604/8330 1" soft dome tweeter

pictured below- NAA variant.





Crossover optimised for smooth in room response. No smoothing applied*
-3dB/-6/-10dB: 40/35/32Hz.

Aluminium model:



Phase alignment at crossover frequency:

Another way at looking at the above chart, for those unfamiliar, is the reverse null.
At almost 30dB deep, indicates phase coherence at the crossover region, resulting in a speaker that has exceptional imaging.



Polar maps:


Dispersion is exceptionally wide past from +/- 45 degrees horizontally. And +/- 15 degrees vertically.
This means it has a sweet space, not just a sweet spot.


Paper cone model:






Danish Duo Maxi
8” Purifi: in 28L cabinet. status- awaiting cabinet completion.



Pictures and specs to come:


Danish Duo XL A high sensitivity, high dynamic range speaker with twin 8" Purifi PTT8.0X-08 + wave-guided tweeter (TBA) - MTM or MMT 2.5way.

status- awaiting tweeter

How to get build plans?
Donate funds to a charity of your choice; then send me the receipt. In exchange I will send you the plans.
100% proceeds Will go to a charity of your choice.

Don’t know which charities to donate to?
Check out www.givewell.org

Just start a Conversation with me to ask me about plans.

PS. Pictures and specs will updated as details evolve

Full disclosure: I sent the Danish Duo cabinet and drivers to @bikinpunk of www.erinsaudiocorner.com to measure on his Klippel NFS. He kindly donated his time, and the use of a $100K USD machine to “measure the drivers for the benefit of the DIY community”. Erin did not ask for any money; nor did he ask for anything in return.

No sponsorship or kickbacks were involved in the design of this family of speakers.
I decided to release the design as “donate-ware”.


Edit: 2024- 02/04/24

PLANS- No Longer Available.

I'm considering adding secondary HV fuses to a Tubelab Simple SE project I'm building. The secondary winding voltage is 720VAC RMS and the current during normal operation should be about 170-200mA RMS. Assuming a fault, such as the rectifiers failing and turning into short circuits, the fault current would be less than 4A based on measurements of the PT's winding resistances and verified with some simulation.

According to the Valve Wizard's article[1], "secondary fuses can be of the glass (non HBC) type since fault currents are greatly limited by the transformer itself". This is also suggested by a Littlefuse document quoted in [2], although by now the document has been revised to only say that you should contact Littlefuse if considering using fuses above their voltage rating. I have contacted Littlefuse, and their response was essentially that, given my low interrupting current, I might be able to use a 250VAC fuse, but I should test.

So, I was wondering if any of you had any experience with using 250VAC fuses (either the glass or HBC types) at such voltages and had them interrupt the circuit during a fault without exploding. If possible, I'd rather use 5x20mm fuses and these only come in 250VAC ratings at 0.25A or so of operating current. Note that I'm considering the case of fusing each leg of the HV winding, as suggested in [1], and not the CT. In the latter case the voltage seen by the fuse would be half, so just 360VAC and the situation would be better.

[1] https://www.valvewizard.co.uk/fuses.html
[2] https://dalmura.com.au/static/Valve amp fusing.pdf

Hi everyone,


Interested in the discontinued Soekris DAC1101.

Anyone want to sell theirs to me? Can pay swiftly via PayPal, if the price is ok.

Soekris DAC1101, 2 pictures of it ...



Have never heard it, however read the forum thread here when it was new and there was much excitement surrounding it.




The DAC at this link - http://www.soekris.dk/dac1101.html

Have a nice day !


Kastor

100 Ea. Soviet NOS 6N30P-DR super tubes. All same date, 1986.
Wholesale 15,000 Usd.
No bargains.

Hi there, I have been working at getting a pic16lf1936 to talk to an ADAU1401 over I2C.. Finally I managed it..

The command string addresses a single Sigma Studio on/off switch (or design element) which activates an LED.
My code is exactly the same as that sent from Sigma Studio. The design is loaded into the self-boot EEPROM..
I can only think that when Sigma Studio connects to the ADAU1401, it issues some commands that I am not seeing as this simple design runs from within Sigma Studio..
Does anybody have any ideas please.

Hi,

I need ibanez ibz10g schematic. Is there ?

Please contact me.

Thanks.

Oliver and Locanthi gave us the correct version of Class AB in the last century. However, many have succumbed to ear-damaging Class D in the new century. This is while it's been several years since the improved versions of the old good Class AB were introduced. One of those are DoubleCross by Cordell/Hegglun that is at least order of THD better. Another one is my patented Class ABBA that is 30 times better than plain vanilla Class AB. The hardware costs for those improvements are negligible -- for Class ABBA it is just a pair of additional low power resistors. The detailed schematic description, PCB gerbers, BOM, and datasheets for my amplifier are all here:

https://www.patreon.com/posts/umzch-vv-xxi-v-81828557

The screenshots of AB/DoubleCross/ABBA simulation in easy-to-compare side-by-side layout are attached. The simulation was made using Microcap 12 that is probably the best simulator for audio circuitry. Endless thanks to its creator, Andy Thompson.

My master class with online analysis of all three circuits is available here (with multilingual subtitles):

Login to view embedded media
Photos of printed circuit boards and assembled amplifier: https://www.diyaudio.com/community/...d-state-pics-here.96192/page-382#post-7799636

All Microcap *.cir files used for analysis can be found here:

https://www.patreon.com/posts/cravnenie-av-po-112445977

The copy of a free Microcap 12 install with all required libraries can be also found here:

https://www.patreon.com/posts/podstrakhoval-12-84096514

I hope we will overcome the Class D dominance together, won't we?

hello all this is my firtst post ,i have a pair of jm labs 915's that were abused and i want to recap them . to the revised 915.1 i think it was for better bass. i have the schematic .maybe i can post it but i think it for the 915. focal uk was helpful to supply me with this. so what i am looking for it suggestion on new caps and such. i see the mundorf is very favored so i am willing to use them. i have attached the crossover schematic file for all to look at.

thanks any help will be grateful.

I am selling my CD23 FMJ (Full Metal Jacket = heavy duty chassis and case).
.
It uses the renowned & very expensive dCS Ringdac and PMD100 HDCD 8x filter.

Defintiely the most impressive CD player I have owned and plays my CDs faultlessly.

It's in excellent condtion and comes with the original remote and mains lead.

On ebay at £395, discount for forum members. (UK buyers only as the overseas shipping & insurance cost will be high)

Pleease PM me if interested.
Thanks

Attached is a useful bass boost schematic for use in small desktop speakers. You can adjust components values to invert the bass roll of of your particular speaker. The overall gain remains zero dB so it can simply be bypassed whenever you want without a step in the overall response. Nothing spectacular but awesome on small speakers.

I have been using my triamp for the last 5 years and am looking at building a class D amp.
I have no experience with class D and am after some advice.
Power would be around 50w per channel and the plan is to eventually build a triamp unit.
I have a preference for using discrete components as I have had problems in the past with discontinued chips.

Hi, a friend interested in EF37 and other very similar tubes. I made PSpice model for triode connection, as in the data-sheet.
G2-K, G3-A.
I could not find the value of capacitances in triode mode mode.
Cga and Cak are used from the pentode mode, BUT Cga is missing.
I approximated a bit smaller than input capacitance to 4pF.
So if someone have informations of triode mode capacitance for these tubes please send?
Thanks.
.
This is pretty linear tube. But it has some specifics... In resistive mode load, for linear least distortion mode, Vb is reaching more than 400V of HV value. That is not the issue to use with power tubes which are already have higher HV Vb value to use for this tube.
.
Another option is L load. But that may deserve higher value of inductance, implicating to higher capacitance for more turns. Because the internal resistance is aprox. 9700 ohms... these tubes are not so powerful drivers because of the higher internal resistance and Zout of about 7800 ohms. But distortion is low for that huge output p-p swings and input will not go into positive range in the Ug = -3V for 2Vrms input...
.
Maybe the best option to avoid that high voltage, complicated inductance is some SRPP mode, or Gyrator load?
Gyrator load is introducing non-vacuum tubes elements, that might be not acceptable for tube purists 🙂. But may be an argument to have more affordable and compact load, and if we use these elements in load why not to use them in the PS regulator supply?
.
Al in all there is very useful tube in triode mode as in pentode mode.
Some of the informations as working point values, loads, internal resistance, input and output voltages, output resistance...
.





Copy code content and make .inc file with some TXT soft. Just rename .txt into .inc for PSpice.
You can reuse it in Tools soft and remake LTspice version?
cheers
.

Hello,
since diytube (Shannon Park) has stopped selling circuit boards, but apparently there is still a lot of interest,
i created clones from the pictures and circuit diagrams available on the net and made some improvements to the layouts.
Currently available pcb's from getsetgo, clementine, poseidon and dynaco ST35, if you are interested just send me a PM 😉
best regards

NEW: now also for DYNACO MK3 Oktal or Noval can be used!
PCB color as desired!





Merlin RIAA Preamp
https://www.diyaudio.com/community/threads/merlin-riaa-preamp.308369/page-6

Budgie's Preamp​

https://www.diyaudio.com/community/threads/resume-production-of-budgies-preamp-pcb-2014.366869

Greetings all,
Vituix CAD's Enclosure design tool uses a driver parameter called Rms [Ns/m] .


According to Wikipedia, it seems to be a measure of impulse/distance or momentum/distance. https://en.wikipedia.org/wiki/Newton-second
Playing around with Vituix, I see that its value in critical to calculate sealed box volumes. In that changing it makes a big difference in calculated box volume for a given Qtc. In addition, Vituix won't let me enter a new driver without it.
Problem is: this parameter is not in the data sheet for the woofer I want to model (Dayton RS150-P 8A).
Curiously, Rms value for other Dayton Audio drivers are in the Vituix database. But Dayton has not specified this value for those drivers either.

So the question is: Is there a way to find the correct value for my driver? Is is calculated from other published values? How did the builders of the Vituix database get the Rms values of the other Dayton drivers?

Hello, I'm new to this group. I'm trying to find a Servo Amp for my Acoustat Monitors. I had an amp go out and traded that amp for two transformers that will accept other amplifiers. I would like to see if I can find a replacement amp that will match the one I still have. Currently running them with an Audio Research solid state amp.

Sold

Hi, has anyone used the Dayton audio RSS315HO-44 ?.
Thinking of getting one, I wonder build quality - sound , etc. if it's good or worth the money ..
- Bruno.

Hello, my name is Josh. I got my start stuffing PCB for now defunct solar company called Acro Solar building tracking systems for parabolic dish water heaters. After that, I got my fix doing Ramsey kits. The blinking LED Christmas themed stuff has been missed in the kid's stockings. I miss building them and wish Ramsey still did kits.

After that, I have been building stuff from the store. Built an ACA, a B1 with Nutube, an Aleph J. Building a Noir HPA that I am putting cigar box but that has been sideline for building a Pearl 3. In find right resistor for R27 on the Pearl 3, I hooked up the positive power to the negative input and no I only have one working channel. But it is all good, it is forcing me to learn better trouble shooting skills.

I would like to thank everyone in this community, I never thought my stereo would sound this good. It is all because of Y'all. Thanks! It is humbling listening to it.

Hi,
I'm trying to connect my Raspberry Pi i2s directly to my DAC board. I have a few options, if I understand it correctly:
1. USB - the board supports - sounds o.k.
2. SPIDIF - also supported - sound much better
3. NOS with the TDA1541 - haven't test it yet, but I guess I know how to do it. By the way, this kind of connection to ProtoDac sounds very very good to my ears, after reducing the Vin of the ProtoDac to 4.3V and feed it with separated linear power supply...

Now, I can't find out how to connect the SAA7220P/B to i2s. I fail to match the i2s output to the correct pins of the SAA7220P/B. Any support in mapping, or saying what am I doing wrong will be highly appreciated!

Thank,
Jacob

I have a Topping A30 Pro headphone amp that suddenly died with a loud pop while listening. Since then one or more relais are constantly clicking, when turning the unit on. There appears to be 7 Omron relais on this board.

So I believe the protection circuit is doing it's job and it's constantly triggering. I tried with a different power cable, to rule that out.

I hoped it might just be the power supply modules, so I ordered new Meanwell IRM-20-24 and soldered them in - without a change, still clicking.

How would I start debugging the issue? I have a UT139E multimeter with regular probes, they might be a bit large for live testing in fear of shorting, though. Can I passively find the issue?

My hypothesis with the constant clicking is that something with the power delivery has to be broken?

I have for sale a Sound Technologies ST1200 Stereo Test Panel. It's used but in working condition (or at least I think it is - I've never installed/used it). I've owned this a number of years. I have no idea of it's value - how about $50 plus shipping (which shouldn't bee too much - it's large but not heavy.

Vendo um vídeo no youtube, alguém relatou o seguinte:
- Os capacitores de poliéster/bipolares, tiram o timbre, atenuam um corte exagerado e perdem-se variantes minínas de áudio.
Já os capacitores eletrolíticos, fazem tocar a mais ampla faixa de áudio, por ser comum, filtram Cross Over Preferences apenas 90% ex...
Resumo, os 10% que passam, deixam o tweeter com os agudos mais completos e vivos, descobri com testes em laboratório e RTA e DAT.
Ocorre que, se ouve variantes nos agudos mais legais "cheio" completo.
E com capacitor bipolar ou poliéster, limita e o agudo, fica sempre com o mesmo tom, não importa o estilo musical,
o tsss tssss fica sempre o mesmo sem variantes...
Já com capacitor eletrolítico, fica diferenciado, responde de acordo com cada instrumento e efeitos um agudo de timbre variável,
notavelmente fica perfeito para ouvir assim.

Dai alguém aqui já se deparou com isso?

I understand that the HV needs to be delayed for this tube. If I use a separate switch between my PT CT and ground would a 250VAC switch be sufficient?

Hello,

I have an old stax extension cable whose plug got broken solder joints inside. It has pins of the same type as this one but in a different housing:



I understand it was made by amphenol way back then. Since it is a very old part I'm having trouble finding any info on how to properly solder wires to these pierced pins...
Of course it can't be soldered pointing up like this 😎

I tried soldering with the plug pointing downward at a slight angle with the wires sticking out, it kind of works but I had to file the pointy wire that was left and I'm not sure there is a very good wire contact surface in there. I can't help but think there is a better way.

Closest thing I found to a solution is the so-called "flooding" technique :
I think could do it on my heat resistant silicone mat. I'm guessing one has to develop a "feel" of the degree of solder hardness when pushing down the wires while reheating the solder... then try not to move the wire while the solder hardens again. Wires probably need to be tinned prior in order to have some rigidity.

If that is the correct procedure I will proceed to do it although it seems rather cumbersome.

Thanks in advance for any insights ! !
-Joris

I cant see the number on the small 8pin chip, please help.
File a

Ahoj všichni, stavím hlavně lampové zesilovače.

nm

The drawer wont come out but I'm not sure it's the same problem I repaired 15 years ago with the CDM-9 transport. Here's a close up video of what happens when I press the eject button:

Login to view embedded media

I was approached by a vendor to review his discreete opamps on my digital amp modules.
In my enthusiasm I said sure no problem. I offered him to send the opamps back after the review just to protect myself from being accused of a biased opinion.
When I wanted to write the first part of the review (fresh out of the box sound) I found out that the company is not in the vendors list.
Since swapping opamps can hardly be considered a diy act does a review of such a component belong here?
The last thing I want is to get accused of interest driven behavior.
On the other hand I know that many people would be glad to know how a discrete opamp can transform their digital amp.
But where is the platform to do that on this forum without breaching any rules or upsetting people?
I have no problem sending the opamps back and forget about the whole thing if that's the only option.

What are your thoughts on this?

Greetings Klaus

I'm not sure I will ever complete my LM3886 amp kit because my case is too small or my transformer is too big.

I also have a Brian GT LM3785 kit.
I can run the LM3875 or LM3886 off of a Meanwell power supply I have.
But then it won't be "audiophile", no?
So maybe I won't need the rectifier and 50v caps.

Should I use these 50v caps to replace the 63v caps?
The 50v caps seem to be about double the volume of the 63v caps.

Or any one want to sell me some 10,000 uF 63v caps?

Bought this amp as none working in the hope of an easy fix, I replaced all the capacitors and 2 resistors ( burn marks around their pins ) .
All was well until i heard a loud crack through one speaker and the amp powered itself off , I unplugged it , I’m just guessing now that it potentially be the output transistors which only have the chord markings so I can’t identify them, can I identify them by unsoldering them and then connect my peak atlas to the pins and the one retaining screw ( pen shows where they are ) they’re very difficult to get to ! I can see the printing on them but it relates to nothing.

After some research I went through trying to find suitable midbass drivers for my latest design, I started paying closer attention to the motor noise which affects some cone drivers under certain operating circumstances.

In the case of the B&C 8NDL51, which is one of my all time favorite midbass drivers, its typically not an issue when using it specifically as a midbass in a small sealed enclosure. The lack of pressure differential between the backside of the cone and internal space behind the spider cancels out most of the excursion noise. In free air, the motor is noisy due to increased air velocity across the VC gap. This is how B&C purposely designed the driver for sufficient VC cooling. It only becomes audible when there's a pressure differential across the spider surface. Even though the driver motor is dead quiet on the 8NDL51 in a smaller sealed box, I wanted to explore noise reduction options with it based on feedback from others having used various other pro audio drivers for critical applications.

Warning!!! Not responsible for damage to your driver if you attempt this modification !!!

The solution to a noisy motor on a cone midbass is usually straight forward and very simple. It involves a soldering iron and a steady hand. Just apply light pressure with a blunt tipped soldering iron onto the desired spot you wish to create a vent hole and let the heat of the iron do the rest. In most cases, 4 to 8 evenly spaced 3/16" holes are sufficient to quiet the driver down to the point the motor becomes silent. Using the soldering iron to burn in the vent holes avoids any debris from being generated and entering the VC gap. 700 degrees is the preferred starting point depending on spider material used along with any coatings and treatments. Most spiders require only this much heat to give way. Some silicone coated or nomex spiders may need more heat.

The goal here is to reduce airflow velocity across the restrictive vent holes and VC gap on most higher powered cone midbass drivers. This may have an impact on cooling at high power levels, but in most cases there have been no observed negative consequences to driver longevity or reliability. Perhaps under the most extreme operating conditions this may have an impact on cooling, but so far I haven't seen any issues on the countless drivers I've modified to reduce excursion noise. I do this to alot of drivers, but mainly only if they exhibit any noise and don't possess any pole piece venting or other means of ventilation. Doing this to a driver equipped with a phase plug is pointless for obvious reasons.

So if you have issues with a noisy motor on a cone driver, try this. It has never failed me to date, but as usual, YMMV.

Simplified diagram.

I bought 5 Tannoy active monitors and two of them have a slight distortion across all frequencies. I’ve taken one of them to three local techs and all said they can’t fix it. They said there is nothing obviously wrong. They even test it and say it measures fine. But it’s clearly distorting.

I swapped everything around including power capacitors (mounted separate from the amp board), drivers, boards, and even the transformers. From that I worked out the issue is coming from the amplifier board which includes the board, transistors, heat sink etc.. Photo attached which is terrible I agree.

Now as you can hear, I don’t know much about electronics. There is no schematic that can be found and Tannoy is incommunicado.

Any suggestions go about finding out what the problem is? I can do things like measure resistors, capacitors, remove and replace passives etc.. I was thinking about placing a good board beside a bad one and start measuring stuff until something is different. Pretty crude.

I'm planning on an OTL headphone amp and was wondering if it's worth the extra expense to use film output cap's, or just go with electrolytics bypassed with Miflex copper.

I have for sale an HP 8903B Audio Analyzer. It was calibrated in 2014 and still works fine but I haven't used it for several years (now using Quant Asylum 401). Asking $300 plus shipping, assuming PayPal friends & family to avoid fees and taxes. It's refundable if it's not working when you receive it.

Cheers.

I have for sale some 2SK851 Thoshiba mosfets, minimun quantity to buy is 4 mosfets.
All supplied mosfets are measured to be matched.
Price is 25€ for the 4 mosfets more shipment.
Payment by PP
I have more parts from Thoshiba that you could check here:
https://www.ebay.de/usr/rocksandsound
Regards

To Buy or Copy

THANKS and Happy Thanksgiving!

Charles

THANKS

Both for $50.00 + shipping
I'll also include 2 microphone cables (one quite long ;-)
or pick up in Manhattan.

hi guys.
given that car amplifiers have already a gain pot can i add a resistor divider at the input?
gain is too hi and i need about 6-8db attenuation when the gain is all the way down.
input impedance is 10k.
thanks

Thank you for allowing me to join.

I'm the wrong side of 60 and have been involved in the professional recording industry for most of my adult life. A short daliance into mainframe computing and training to be a lawyer aside. After recording a good many tracks using two mono reel to reels I moved onto a Teac A3440 at the age of 18 (I still have one). I became studio engineer and Director at Horizon Recording Studios ( The home of Two Tone) at 22 and enjoyed my time recording some great artists. Eventually, after a few years retraining (see above) and marriage, kids and so forth, my wife and I set up Mantra CDs & Recording in 1997 which we have run ever since. We have studios in mid Wales and the Wirral and are currently converting a 7.5 tonne horse truck into a mobile studio and pa truck. Alongside this I am very keen on speakers, particularly British, vintage hifi. I have a pair of 15" Tannoy GRF's, Wharfdales Denton and four pairs of Leak speakers (2 x 2060, 600 and some mystery diyers with Leak drivers). I want to learn as much as I can before renovating/ improving the Leaks, but am also very interested in nearly all aspects of audio.

Hi all,

Any engineers or tinkerers that have some input on the following?

Looking at a repeatable way to measure various metrics that can relate to tactile response from a distance and specifically not from a vibrating platform, but rather from various speaker designs. It seems really challenging actually to get a reliable way to measure something remotely as sensitive as how we perceive tactile response from SPL and other factors. I already have been able to reliably measure acceleration changes from my pneumatic platform as it bounces up and down to relate it to tactile response. But now I want to get more specific with speakers at a distance.

I'm trying to make something crude but functional for this, just to satisfy my own curiosity. I can measure acceleration of my pneumatic platform and that works well. But I'm interested in another way to measure speaker source tactile response from a distance, of say 2 meters, so its repeatable. I would like to be able to set an SPL level at a frequency or range, so that it can be repeated with different speakers so that the SPL at the frequency is the same (or very very similar) and then the differences can start to be examined.

I was thinking of building a diaphragm or drum. Nothing big. A small frame with a thin material like paper between the frame, held rigid but not immobile. Small enough dimensions to resonate primarily at higher frequencies, but large enough to have resolution and sensitivity to capture pressure changes and other things as waves impact it. On the diaphragm I will attach a sensor that captures acceleration, angle changes and angular velocity changes. This is not a lab level instrument, just a fun little sensor that does that.

My primary curiosity is to see if I can capture any meaningful differences between SPL and anything else. For example, if SPL at a frequency is matched, is there a tactile response difference from a single large driver with higher excursion, vs many smaller drivers with less excursion from a distance. Is there a tactile response difference from a driver at a frequency and SPL compared to a horn or port or slot with air velocity involved at the same frequency and SPL at the same distance? Just things like that, that I'm curious about. Maybe its pointless. But I'm curious. I'm not sure if I even have an instrument to capture this, so I'm just throwing around ideas. Any thoughts or help on how to capture something like that would be appreciated with simple instruments.

I did a prototype and it seems to capture some data. It was no capturing acceleration hardly at all (minimal). But it was capturing angular velocity shifts in X and Y axis. Mostly in X axis (which makes sense I suppose, as the wave propagated towards it from that plane and passed over it). But I had other frequencies that excited it in the Y axis. So then that means perhaps the frame of the diaphragm/drum was causing problems. So, many things to figure out to eliminate to improve control and remove random and bias.

Just thinking out loud. Any input appreciated.

Very best,

I have some tubes for sale that I dont need anymore.Plese look on pictures.This are verry little used or Nos but 100% in good working condition.There are mostly matched pairs and on the bottom this tubes without box are only 1 piece from each design,becose of diferent internal structure but all are 12au7/ecc82.For more info plese contact me.
Prices listed under are per piece,only 6h30pi ist per pair and alld 6x5gt are per pair!!!

I have for sale a Hameg HM203-6 20MHz 'scope. It's in working condition and includes the "CT" option - a basic component test that can be helpful for troubleshooting in-circuit devices. This is an analog scope and makes a good first 'scope. I probably have a basic test lead that I will include.

I'm asking $75 but open to offers. Shipping probably about 20 - 25 dollars in the US.

For sale are some high quality audio equipment, all in perfect working order and condition. Pics below.

Please try emailing me as I will get notifications to my phone, I find it hard to find time these days to check the forum. - richlund70 (at) hotmail (dot) com

2) XEN SHPP SOLD

3) High quality 5V linear fused PSU Custom design based on the Whammy PSU design. This has a DEXA NewClassD UWB2 MK 2 Regulator worth £30. Will include two spare PCB's good for pos or neg rails - £40 plus PP

4) Capacitor Multiplier modules some fully built and working along side part built boards with a load of components, these are excellent power supplies, just need a transformer to use. - Make an offer,

6) Toroidy audio grade toroids -
1 x 30VA - 2 x 20V / 230V mains - £20
1 x 20VA - 2 x 16V (0.5A), 2 x 16V (0.1A), 2 x 12V 0.02A) - £20
1 x 230VA - 2 X 40-0-40V, 2 x 49-0-49V - £30

New old stock pair of Tango FC-30-3.5S

Perfect output transformer for 300B, PX-25, 2A3 tube amplifier.

Primary impedance: 3.5k ohm
Secondary: 4, 6, 8, 16 ohms
Power output: 30w
Frequency response: 20Hz - 100kHz
Primary Max DC Current: 170mA

Worldwide airmail shipping with a tracking number.

Price: 900 EUR

vented 2 way driver selection..

2 subs, vented mivic awx184.. tuned around 32hz .. Qts 0.36.. 230liter f3 30hz..

for the tops I was thinking Faital hf10ak and a horn similar to 18 sound xr1064..
and LF something like 18sound 12w750, qts =0.37 in 8ohms and 0.29 in 4 ohms

crossover sub top around 80hz, tops passive.. and then integrate the subs passive or active to the tops.. any thoughts?