When using the dual mode (class D/class AB) PAM8406 IC in class AB mode (mode pin low) can I connect one side of the speaker outputs together to drive headphones?

Anyone have any service info on how to adjust the Delta V adjustments int he sunfire amps that use the Tracking downconverter scheme??

The factory preamp design in the Onkyo A-5 is marginally stable. This thread is about a complete and tested fix which retains the TA7136P IC, preserves in-band behavior, and doesn't involve any drilling.

I live a half-mile from a strong FM radio transmitter. This is a good way to find out which preamps are stable: that FM broadcast bleeds right through the noise floor for those that aren't.

The A-5 preamp showed the usual signs of oscillation. It had an angry noise floor that varied in volume if you touched the chassis or moved any attached wires. You didn't need a source if you wanted to listen to one particular FM station. The FM pickup was worse with the chassis off, and audible with it on. A stable preamp shouldn't become a tuner even with the chassis open.

The fix is in 3 parts, there will be a post for each.

• Create a spice model of the TA7136P op amp so we can evaluate its stability.
• Change the compensation so that the circuit is stable in spice.
• When that doesn't work, notice that the NFB loop is physically large (it spans 3 circuit boards). Reduce NFB node impedance at HF, to improve the chance that our spice model is accurate. This worked.

Decided to keep it.

Hello, there is any chance to find a Thomann T.amp TSA 4-700 diagram or wich are auxiliary voltages due switching power supply is burned at all and I would like to test the rest of it.

Thanks

For sale, NewClassD Ultimate Edition MK2 single opamps, two pieces.

Price: 60€ + shipping cost

This was a fun and easy mod. You don't have to drill much and there's plenty of space to add the few new components.

I only modded the flat amp, I didn't touch the tone amp or the phono amp.

The factory flat amp simulates at a -105db distortion floor. With mods it simulates at a -120db distortion floor. Both sims used a worse-case source impedance of 25k.

The mod works like this:
- Replace the FET input stage with degenerated bipolars.
- Modify the input network to be AC-coupled to work with the bipolar's nonzero base current.
- Remove the Miller compensation cap, use lag compensation instead.
- Add a capacitor to the factory cascode to strengthen it. This allows for good distortion performance with high source impedance. Without it, the Early-effect nonlinear base current in series with the source impedance will introduce an error that cannot be NFB'd away. This cap must be large enough to work at LF.
- Adjust a few other component values (C706, C707, R715.)

Why the compensation change? The R-C pair at the tail of the input stage interacts less with the lag cap than the miller cap. This lets us give the overall loopgain plot a deeper phase dip and allow more NFB in band.

I modded one channel first and kept the other stock to compare. The mod sounds better to me and it certainly sounds different. It sounds louder than the stock circuit even when carefully level matched. I've often found the stock circuit to sound a little "soft", with just a subtle "fuzz" to its sound. It was a mellow sound from the factory, and this mod wakes it up some.

It's amazing how two amps or preamps, both with excellent accuracy (distortion below -100db) can sound different. The "before" and "after" of this mod being a great example. It's a subtle difference but I don't think I'm imagining it.

I have a tube preamp design that requires a + Ve and and - Ve supply rail .

I was hoping to find a E core transformer with the following specs

• North American use ( 120 Vac primaries )
• something in the ball park of Dual 90 Vac or 100 Vac secondaries
• 50 VA to 80 VA
• use with full bridge rectifier
• buy from a North American vendor

With a passive supply , this would give something in the order of + / - 126 Vdc or +/- 140 Vdc rails .

So far I've had no luck finding such a beast . But the Hydro voltage in Japan is 100 Vac ( 50 Hz or 60 Hz ) .
Does anyone know of a North American to Japan voltage conversion transformer that would fit the bill ?


Thanks

One of the Universe's inscrutable tragicomedies is why these two abominable songs are used in near all speaker demo videos!

Does anyone really like this kind of music, and/or test their speakers with such stuff?

Maybe the guitar line on the Nils Lofgren song I can accept as something of a test in a narrow band, but jeez, the Dire Straits dirge - it's the MOR equivalent of Bass I Love You.

Approximately 15 years ago I had order 2 pcs. Vifa tweeter with large surround roll (new released at this time) but without ferrofluid.
I ordered here:
https://web.archive.org/web/20070217060009/http://www.vifa.de/
Unfortunately I forget the model naming.

At this time there are various basically series - two series without ferrofluid:

1) with phase plug - go to
https://web.archive.org/web/20070808054348fw_/http://www.vifa.de/produkte/DBXT300K.pdf
2) without phase plug (as mentioned in follow, but also without ferrofluid).

The follow mentioned models use all ferrofluid (type APGS11N)

Vifa XD270 series
http://www.plus-elektronik.de/shop/bilder_vifa/dbxd270f-4.pdf
Peerless DX25TG59-04 (first successor):
https://products.peerless-audio.com/transducer/58
https://www.lautsprechershop.de/pdf/peerless/peerless_dx25tg59_04.pdf
https://www.hifisound.de/Do-it-your...DX25TG-59-04-Vifa-XD-270-F-4-Fabric-Dome.html
Peerless DX25TG09-04 (second successor):
https://loudspeakershop.eu/pobieranie/dx25tg-59-04.pdf
https://heissmann-acoustics.de/test-vifa-peerless-xd-270-f4-dx25bg60-04/
Scan Speak D2604 series:
https://www.scan-speak.dk/datasheet/pdf/d2604-830000.pdf
https://www.scan-speak.dk/datasheet/pdf/d2604-833000.pdf
SEAS H1280-06 22TFF:
http://www.seas.no/index.php?option...ff&catid=45:seas-prestige-tweeters&Itemid=239

I want to know the type naming resp. order code of such tweeters with large surround roll and without ferrofluid.
Thank you very much in advance.

P.S.: This 10 years old thread under
https://www.diyaudio.com/community/...-without-phase-plug-ferrofluid-wanted.247341/
was closed - thus I start a new thread despite the same topic.

I'm looking for a replacement part, Revox B77 Meter Tooth belt.
The one that used to be there is vanished !
I guess it felt to dust with time, nowhere to be found.


If you know where I could get a working replacement, that would be nice.
Of course, I'm not willing to take a second mortgage to get one ;-)


Thanks for any advice.

Good morning to all,
I recently obtained an interesting PowerAmp - Kenwood L-1000 M - manufactured around 1990. Concurrently I was able to locate a service manual as well. I got the Amp since it is a member of Kenwood's famed "L-Series" which was manufactured by Kensonic Labs (also known as Accuphase) for sister company Kenwood.

http://www.thevintageknob.org/KENWOOD/L1000M/L1000M.html

Specs are as follows:
http://www.thevintageknob.org/KENWOOD/L1000M/L1000M-block.html

2x150W @8Ohm - 2x250W @4Ohm
Damping factor : 130
THD 0.006% (20Hz-20KhZ, 130W, 8Ohm)
THD 0.0004% (1kHz, 130W, 8 Ohm)
Frequency response 5Hz-100kHz +0dB -3dB
Signal/Noise Ratio : 115dB (Unbalanced), 125dB (Balanced)

What I'm looking for are ideas how to modify this nice power amplifier to make it even better. It has excellent specs but due to some reason, it didn't receive top grades in German higher end audio journals. (Like Stereoplay, Audio and Hifi-Vision). Maybe because it was too cheap for their preference ? I think the amp originally costed around $3000, that's way below the $10K many good Accuphase poweramps sell for.

It also is full of high quality components. Maybe there might be some "easy tweaks" to unlock the potential of this design, which shouldn't be far too different from Accuphase's own.
http://www.thevintageknob.org/KENWOOD/L1000M/L1000M-edwin.html

The design has some oddities / goodies
1) Full symmetrical layout
2) 2x 270VA transformers
3) 47000µF caps in the power unit
4) Point to point wiring

Aspects that I found questionable (starting points to modding ?)
1) Variable resistors (potis) in the input path, one per channel - is this necessary ? does it introduce noise

2) Maybe try to get caps to tighter tolerances - replace elkos with regular caps where possible

3) Get metal film resistors of smallest tolerances (Holco 0.5%) to replace resistors in audio path, at the extreme: use bulk foil types

4) The "input" board - uses 2 Opamps : 2x Dual Opamp NJM4580 from JRC / New Japan Radio. While these are ok and relatively low noise, there is still room for improvement in noise and especially slew rate (Contemplating AD797 for example)

5) There's a switch from XLR to Chinch Input at the back of the Amp. Well, it would make sense to "migrate" the switch to the front and feed it from 2 seperate preamps: one analog and one digital "cross connect" (with highest quality DA/AD) for example..

Just to give the full picture about my endeavour, it wouldn't be me who would do the modding, a german modding shop would carry out the project. However I'd like to be able to provide useful inputs to them, ultimately in the form of a "checklist" and for me as a a "project supervision" tool. Being familiar with most concepts, I know more than basics in electronics, however I've been at odds with the soldering iron whenever I tried it <g>

any comments and ideas welcome. Even more so because I know this is a rather "strange" and "exotic" amp - manufactured by a company with more than a good reputation..

best rgrds from Vienna/Austria
CROSSY

Hello!
Can anybody recognise this triode? Can't find anything on the Internet, seems to be a power triode, octal base. Shows "10E/1<unreadable>" but that seems to be common with many vintage valves.
Thank you!

I'm in Dorchester (Dorset) in the UK and travel regularly to Buckingham (Bucks) along the A35/A31/A34. I could deliver it if you're close to either of those places or not too far from those roads. I'm not going to post it because it's 6.5kg and I've no reliable way to park the drive mechanism.

Owned for more than two decades and purchased from dealer as former demo model. It's not been used for the last 5 years or more. 16 bit version, 2* S/N implying that it could have been upgraded to 20bit at one time.

Was going to sell it as working, but on starting it up, it has a problem with skipping. Sometimes it plays perfectly, sometimes not. So I suspect a corroded/dry joint somewhere in the drive electrics but I have neither the time nor inclination to diagnose & fix (mostly too much else on my plate). In addition to this, the display switch sticks if you push it at the bottom (so don't!). It can be released with tweezers and drops the player into config menu if you power on while stuck.

Cosmetically in VGC and I have the remote.

Hello everyone

I'm returning after a few years away from the hobby and forum.

I'd like to build a DAC for my next project, preferably based on a popular design, where the issues are already worked through. Even better if PCBs or modules are available.

My only requirement is that it needs to accept digital optical input (from the TV) and output stereo via RCA connectors to the amplifier.

Any suggestions?

It was designed for me, by a very famous tube tech, l had it for many years, then l sold it, l will re make it, now, enormous sound stage, very up front, lively, fantastique. Wait l will post the schematic. Very minimalist.

I have been trying to sim a unity horn in Akabak but I'm getting a large peak and dip in response at just over 200hz. I have been moving things around to try and get rid of it.

The dip is the same frequency as a peak in the radiation impedence and a dip in the electrical impedence

Could this be an issue with the model in Akabak? How would I get rid of it?

I am using four B&C 12NDL88 drivers in this sim.

4x2SK163,WIMA MKP10. Power supply 9V battery. Price 100€ + post.

Hi all. I have just rebuilt a pair of Quad 50e amplifiers and they sound good no noise at all. I boxed them up and sent them to a friend, when he received the amplifiers and set them up they both have a buzz. I asked him to check to see if anything as come loose in transportation, he as also checked for earth loops. The amplifiers buzz with out a load. I cannot get to see them because my friend lives to far from me I would be grateful for any help that anyone can give me.
Regards Western 91.

Recently I was given a pair of SOWTER model U082 output transformers.

SOWTER TYPE U082

They are good for EL84 type tubes but I am keen to know if these can be adapted for 807 tubes. I have seen the STC datasheet and the mention of running 807's into 8k primaries. These are pretty generously proportioned heavy products.

Tubes at hand include small signal triodes of 12AX7/U7/T7 family. Several 6SN7/SL7's. 68J8 family tubes. And several pairs of 807 NOS tubes.

Some might suggest to follow the Williamson design. If the Sowter type U082 ironware is suitable then I would surely go ahead. Unfortunately I don't have any T&M setup to verify. I do have a few digital multimeters and a surplus 5A variac. At pinch I can buy and learn to use a cheap oscilloscope.

I have experience building basic tube stuff to a print. Such as SE EL34 type amps, linestages etc,. I am an industrial worker thus aware of the hazards including those arising out of 807 having a top connection.

Before committing myself to this project I wish to absorb as much as possible. Would strictly try not to use any complicated CCS and other fancy stuff.

I will still be required to procure the power transformer, chokes, casings and other bits. Planning to make it a weekends only slow paced build in a monoblock configuration.

Looking forward to ideas and help.

I'm watching the Clint Eastwood Film, "The Mule," on BBC2.
It's about 20 minutes in. He's at a wedding sitting at a table talking to his ex-wife?
You can just about hear the unseen band behind their conversation. There's only a few seconds of it, but I recognised the song the male vocalist was singing, it was "Moody's Mood For Love."

Never heard that sung at a wedding. I guess it was Eastwood's choice as a bit of a jazz enthusiast.


Here is the history of the song, which is an improvisation on the jazz standard, "I'm in the mood for love."

Moody's Mood for Love - Wikipedia ​

This is my favourite version.


Login to view embedded media

Hi all,
I am working on a Moscode Minute in A preamp, the issued is L channel was no output in the tape in/out loop.
It works fine in all other input/output include phono, CD and tuner.
Any body had a copy of the schematic ? I find one manual but only with block diagram. Thank.

a pair of nos CRESCENDO film and foil capacitors, 0.10mF microfarad @ 800vdc, long (4") leads. $50.00. These would make a perfect coupling capacitor in any tube amplifier. The price is for both.

Looking to buy upgrade capacitors for my Bottlehead Kaiju.

The current capacitors I'm looking to upgrade are the 0.1uf 630V, 10uf 630V, and 100uf 250v.

I have a little wiggle room on the uf rating for the 0.1uf and 10uf. I can also do 600V+ for the .1uf and 10uf and 250V+ for the 100uf cap.

Bought this to rebuild a cartridge but just ended up getting a new one. This is a top of the line microline stylus, still sealed in the package, perfect for your retip. $195, shipped in the USA. They're 25-$50 more on ebay coming from Japan. Please buy mine because I'm moving overseas and could use the dough.

Unused linear power supply. $117+shipping from Mouser. $60 shipped from me

https://www.mouser.com/ProductDetail/International-Power/IHTAA-16W?qs=0xCm9DOQnC5SxzxTB0ldXA==

Specifications ​

Hi, could anyone help me find a way to generate a directivity index graph from both a vertical and horizontal polar plot simulated in akabak?
I've been modeling a waveguide I've designed for an SB26ADC and I could use vituix cad to find the directivity index, but I think the demo version of AKABAK does not allow for saving of files. I want to try and avoid the tedious task of creating frequency responses from the image tool VCAD has.
If anyone has any ideas, thanks in advance.

Looking at a BMS 5530/5531

One is screw on one is bolt on

I would like to try it on a few different horns of both screw on and bolt on

So , which is the least evil?

Should I get a bolt on CD and use a screw on adapter for those horns , or get a screw on and use a bolt on adapter for those type horns

Any help much appreciated

Hi everybody.
New Guy to DIY AUDIO community, Always had a passion for sound and music, I worked in both the home audio and car industry for a couple decades . My first project is going to be the Amp camp Pre amp/ headphone amp.
Ill start by doing a bunch of reading in the Forums

Hello to everyone,

My son got me as a christmas present a FOSI audio BOX4 phono pre amp.
I am not entirely happy with the sound so I thooght about upgrading the op amp chips. I disassembled the unit today in order to see what op*amps it is using but I don't know if there are any to be honest. The BOX2 model has some socketed TI op amps that could be easily removed but on my unit this is not the case.
Could someone help me understand based on the circuit picture below? Does this unit have op amps? Or is all done by the tubes?

I apologize in advance for my ignorance.

First of all, I don't know if this is the correct forum to post on, if not appropriate, mods please move the thread.

I need to route a mostly digital board with lots of 100 ohm differential pairs that most likely will have to cross each other on different layers. Also there will be the need for a large 3.3V power supply plane.

This is the board stackup:


As using the first prepreg height of 0.0994mm yields impossible trace withs and spacings for a 100 ohm controlled impedance pair I came up with the idea to have no ground plane on layers 1 and 2 from the top and place the ground plane on layer 3 from the top and leave room for diff pairs on layers 1 and 2. Problem is then there is no shielding between them should they cross each other. where would I put the power plane then, layer 4? this would lead to diff pairs on the bottom two layers being routed over the power plane, probably not desireable?

What's the recommended way to go aboout this stackup?

Here's that the impedance calulator comes up with with minimum spacing of 0.127mm (manufacturer requirement) and a spacing to the ground plane of 0.55m:

Thanks to you all that have posted questions/answered them as it has been a great learning tool.

I have a AS degree in electronics from the late 70's but have not worked very much on the PCB-component level.
Most of my work has been operating equipment to simulate environments and running automated test equipment with some manual measurements.
Currently I am installing and programing avionics equipment in aircraft.
I found this forum after connecting my computer to my audio received and wanting to get rid of the hum. I ended up buying a Schitt Modius DAC that got rid of the hum and gave better audio quality.
I have always wanted a mid to upper end audio system but could not justify the cost but at DIY cost I can. So I have decided to build a a10 Preamp and Wolverine Amp with your all's help.

Rick

I'm working on a Baldwin 40 watt organ amp that was brought to me as non-functioning and humming badly. I'm running through a dim-bulb tester. I found a dead rectifier tube (5U4) of a pair, and one 6L6 with white getter. I checked the power transformer and it's making about 430VAC per side to ground, so that's good. I replaced the dead 5U4 and the dead 6L6 with a pair of NOS RCA 6L6GBs. The first cap is a 4uF oil cap and I'm getting only 260V for B+, which seems low to me. Schematic doesn't have any voltage readings. My Kill-A-Watt tells me that I'm only pulling 0.6 A from the wall, which also seems low, but the dim bulb stays pretty bright. It will pass a signal but the volume is very low, albeit pretty clean sounding. Any suggestions for where to look?

I'm resurrecting my old Thorens TD160 Super. Its fitted with a later model SME 3009 arm. Looking for recommendations for a cartridge/stylus that works well with this combination.

It is fitted with an old Ortofon VMS30 MarkII which was a very good unit with fine line stylus, but the stylus is worn, and I would not trust any older stylus to be any good, even if NOS due to deterioration.

Upgrade to an alternative new stylus or replace the lot? My budget is up to $300 Australian.

check out this thread:
http://www.hifi-forum.de/viewthread-185-14422.html
and start from image No 9

JLH1969 headphone amp, 25euro + shipping in EU

Hello, I have a 500.1 rev 11 amplifier, which arrived with a damaged output stage and the mic4427, 1 240 ohm resistor, 1 75 ohm resistor and the 4 irf540 fets were replaced, but now the low ohm led turns on and I notice that it is not I have power on the mic, I only see 1.3v, any advice to know why the yellow led was understood. Regards

Guys, hello everyone! Can you tell me how to properly configure the phase inverter, with or without a filter??? Why am I asking, because the resonant frequency of a low-frequency speaker in a closed box without a filter is 43 hertz, and with a filter of 38 hertz. What frequency should I start from in order to adjust the phase inverter? Sorry for my English.

Hello everybody,

I have these, SM100AK speakers, bought quite a few years ago. They are nice, but I think there are things to improve.
So from time to time, I make some mods, so to make them sound as much as they can. Worth it or not, to put money in these, not sure, but it is like a sport
and it is kind of interesting how things can evolve and improve 🙂

So what was done. I have changed all electrolytic caps to Panasonic FC and Panasonic NHG 4800uF in the power supply. There are some left few Chinese bipolars and
I'm thinking to change them to 'Muse'..? The film caps are Polyphenylene Sulfide, I don't why I changed not to Polypropylene, but it was done a long time ago. Is there much difference between Polyprops and these? Would you increase the size of the power caps? Bypass them with film caps? What would do to improve it?

I have shorted the Volume pots, and improved the sound a lot. The box is made of aluminum, so it has a very nice metallic sound 🙂 I have put bitumen adhesive material inside the walls and that was an improvement as well.

I'm wondering to change the ICs now. It has 3 x TL074 and 1 x NE554. 3 x opa1644 + 1 x opa1612? What do You think?

Any ideas are very welcome on how to improve it even more?



Thanks and have a good day.

I have (2) Ghent Audio 4ch NC502MP DIY Case Kits, solderless connectors. Unused. New.
Comes with everything needed to assemble a 4ch NC502MP build (the Hypex modules are NOT included of course).

Retail from Ghent is $360 per case kit.

Asking $300 each shipped

Hi
another pair of drivers from a never realized project , new , 40% off retail .

asking $700 incl. shipping and pp

see link for specs .

https://www.parts-express.com/Faita...dymium-Compression-Horn-Driver-8-Ohm-294-1327

Good evening,

I'm a newbie Daphile user and I'm not able to set qobuz on it.
My Daphile version, that is installed on an Intel NUC PC, is the daphile-21.01-x86_64. The installation is on NUC hard disk and works fine for example with Tidal.
My problem is that I don't know where and how I can insert qobuz credentials.
I see the Qubuz plugin in Advanced Media Server Setting under "Third party plugin" (see picture) but not in the "Active plugins".
I tried to install the Qobuz app on my Squeezebox, but there isn't a Qobuz app (only Tidal one)

Could you please give me suggestions?

Many thanks to any people that will answer and sorry for my bad english!

Bye bye
Andrea

Hi there, I've been messing around with hornresp and simulating a tangband w5-2143 horn. I'm aware that the compression ratio shouldn't normally exceed 2:1 for high Xmax drivers, and port velocity shouldn't ideally exceed 14 m/sec. But given this is a 5" full range driver with a Xmax of 2.5mm, how high can my compression ratio go?, Is the limiting factor throat velocity?, can I simulate total harmonic distortion?. Currently it's compression ratio is 8.90:1 but it's throat velocity is only 14.5 m/s (at 30 watts). I know that at 30 m/s a port hole on a reflex box will begin to seal over and not function, but my question is will my horn destroy the driver or will it sound horrific?. The reason why I have even bothered to ask is because I saw plans for a XKI cabinet for the w5-2143 here: https://www.diyaudio.com/community/threads/xki-xs-ab-initio-karlson-6th-order-bandpass.268524/

And I would guess that it also has a high compression ratio.

I've always wondered tape packs from raves are so much more valuable than other recordings. The majority this forum believe they seek 'perfection' - a flat frequency response.

Bygones.

Perhaps those who got out during their youth are looking to re-experience their youth. Bose and other big-box manufacturers this. Flat? Flat is crap - nobody's hearing is flat.

Sound is subjective. It's DIYAUDIO - the object of the exercise is to reproduce 'the sound you like'. As the man says," It was the best of times . . ."
If you're of a certain age . . . your first experience of musical joy was "Good Times" being pumped out of 2 x 12" disco speakers in a woefully undersized cabinet with screechy scratchy Piezo tweeters providing the treble. The DJ is maxing-out his 120w amplifier.
You grew up, you got a car. The first thing you did was to buy a graphic equalizer to make the music LOUD. The very next thing you did was to set the frequencies into a 'smiley face' - big-up the bass, big-up the treble!

You never wanted flat.

Working on different DSPs, with ADCs and DACs, I was wondering what happened to the ultimate clock.
Remember 10 - 15 years ago, every body wanted to change the clock in digital sources like CDs to something fancy from better discrete Xtal oscillators, over TCXOs to OCSOs.

Have anyone done some THD test of such changes?

I'm planning on using X1E0000210427 https://jlcpcb.com/partdetail/SeikoEpson-X1E0000210427/C841675 which is a 10ppm Xtal, in conjunction with a ADAU1452

But I could go for a Crystek CCHD-575 https://www.audiophonics.fr/en/comp...p-12445.html?search_query=osci&fast_search=fs
Promising very low phase noise.

Or one could go crazy with a real OCSO https://www.golledge.com/products/sine-output-oven-controlled-oscillator-with-5v-supply/c-26/p-285

Or a NeutronStar!?!
http://www.newclassd.com/index.php?page=36


The big question is whether it has any impact at all on performance, or it is just an impact on the wallet 😉 .....

For up to date pricing and pictures, please visit our website

Buckeye Amps Official Site

Hei folks, iam noob in electrical engineering, to muffle my boredom i try to make schematic and layout for rk27 breakout pcb. So is there any wrongdoing about my drawing?

The driver under
https://www.fane-international.com/downloads/FANE-STUDIO-5FRK-DS141117.pdf
is still listed on the FANE website, but I can't find offers from companies like Thomann.
Whether this speaker is only made to special order and thus no longer in stock ?

I have Nak DVD-10s that I have owned since new. I dusted it off last year after finding an AV-10 and getting that working, and both now power the various vintage speakers that I repair from time to time in my garage.

I only use it for CD’s and noticed that it won’t read a disc for about 5 minutes before turning on. Initially i thought it could have been due to condensation on the laser or similar, but it’s still happening in the middle of summer.

Just wondering if anyone has any suggestions on what to look for. I heard these have failed lasers often, but this one works very reliably once it has warmed up.

I like to ad a power filter to the 2021 Sony VFET Round 3 kit. Could I use the DIY: Linear audio T-Reg V5? It said for tube circuits but it has a constant current source.

Greetings! The meters on both of my XA60.5 amps are running significantly off center, one worse than the other per the attached pic. Meanwhile the XA30.5 is fine.


Should I be worried? Is there an adjustment that I can perform?

Thanks!

John

Hello all,
I just finished my setup where I can digitally stream my audio from the desktop PC to a CamillaDSP server connected to the speakers. This took me two days to get running properly, so I wanted to post here a breakdown of it. Hopefully it will help some of you.

• Desktop PC as source
  • Ubuntu with Pulseaudio
  • Pulseaudio resamples all to 96kHz with speex-float-5
    • PA uses 0.3% CPU still after this, on a Ryzen 5700g
  • PA transmits to network using rtp module (Only 16 bit integer was possible.)
    • load-module module-null-sink sink_name=rtp_2_camilla channels=2 format=S16BE rate=96000 sink_properties="device.description='RTP to CamillaDSP'" load-module module-rtp-send source=rtp_2_camilla.monitor destination_ip=192.168.0.22 port=46908
  • Running pulseaudio with -vvvv, I find all the RTP settings as SDP data. I put these in attached sdp file.
• Raspberry Pi with Raspbian OS 64 - Server for DSP
  • Uninstalled Pulseaudio, only using Alsa
  • Installed ffmpeg, camilladsp, all other dependencies
  • Running attached Python script to check for incoming streams
    • Pings my desktop PC to see if it is on. It shuts down the amplifier if there is no ping response.
    • If my desktop PC pings back, script will turn on the amplifier and run ffmpeg to check for RTP stream.
      • Uses the sdp file to recognize the incoming stream
  • ffmpeg outputs the stream to snd-aloop loopback device at hw:0
    • This creates a virtual device for Alsa and makes it possible to capture audio from an application, in my case ffmpeg.
    • Channel count needed to be corrected for snd-aloop, to match the RTP that has 2 channels. By default it has 8 channels.
      • $ cat /etc/modprobe.d/sound.conf alias alsa-loopback snd-aloop options snd-aloop pcm_substreams=2,2 index=0,0 enabled=1,1
    • It is tricky to minimize delay of this RTP stream but I believe I found good settings. See inside the Python script.
  • CamillaDSP captures from loopback and does its DSP magic
    • CamillaDSP is running as service using camilladsp.service file from camilldsp-config repository
    • Rate adjust has to be on - otherwise stream falls out of sync with sound card
    • For the capture input I had to select not just the card but the device under the card. It had to be hw:0,1 and not just hw:0 apparently (hw:0,0 is playback, hw:0,1 is capture). This took me HOURS to figure out.. oh God 🙂
  • CamillaDSP plays output to USB sound card
    • I had to disable hdmi audio and onboard audio by editing the /boot/config.txt. Otherwise sound card number in alsa was changing sometimes.
      • dtoverlay=vc4-kms-v3d,noaudio # dtparam=audio=on
      • While editing the /boot/config.txt, I also overclocked the Raspberry Pi to 2147MHz
    • Used the 'Alsa instructions' within the documentation of camilladsp to find what formats are supported (192kHz and S32LE with my Behringer UMC204HD)

The setup has very little buffering overall. If I try to summarize latency sources:

• 2ms in local PC Pulseaudio RTP stream output (checked with $pactl list sinks)
• About 20ms I believe for ffmpeg to receive package from network and send to Alsa
• No latency expected from loopback device in Alsa
• Latency inside CamillaDSP - Buffer level is dancing around 1000 samples. My settings are: 192kHz sampling, 1024 chunk size, max queue of 4. Not sure what my latency is, I didn't understand if queue length is set to 4 or another value currently.
• Latency from USB port and sound card - not sure how much

I checked until now only with Youtube video/audio sync test videos and it feels very good. Still adding my loudspeaker filters to CamillaDSP though. I hope cpu load will not go so high that I have to increase buffers.

Hereby I want to thank Henrik of CamillaDSP for the great tool and its just as great documentation. Without the documentation and all support files, I wouldn't have been able to set this up. Great job from him really. So nice now to just use the browser to setup my DSP and also to know that all I need is a sound card and a low cost PC for such precision DSP work.

is there any simple rules that one can follow for creating a good listening space?

i have pretty much used trail and error with not so good results, i have built some larger corner absorbers and
using heavy drapes and damping panels and thick carpets, the result is pretty much a dead sounding listening space,
which is understandable because of all the soft materials being used. it is very quite in there and i a like it to
some degree but when listening to music in there there is a very prominent lack of ambience or high frequencies,
so much that i have brought in some reflection surfaces to the back of my room. to me it sounds very annoying and
unnatural not having high frequencies reflections comming from behind.

i really would like to do my room acoustics a little more scientifically, is there any useful simple guides and
rules how to think when setting up a 2 channel system regarding time windows for absorbtion and reflections and
angles of incomming sounds?

I've been using Volumio for a couple of years and have a number of RPI model 3's dotted around the house. Up to now I've used them for listening to web radio and Spotify connect as a free user. I recently invested in a Topping DX3pro DAC and wanted to try Tidal so I upgraded to the paid version.
In my experience it's just good enough in terms of reliability etc to justify paying for. I've been playing around with the multi room feature and the analogue input feature (I have a DAC with an analogue input which allows me to send an analogue source to other streamers in paid mode).


My experience of these features since upgrading has been very negative. I find that the grouping/multi room feature just causes crashes. For eg, I play an LP or a tape into the DAC with the analogue input and I can hear it on the output of that DAC but when I group another streamer, nothing happens. Then when I try to remove a device, it just crashes and won't respond to the button press.
Other times I've had it working, for eg Tidal playing on the lead device but then when I've grouped another device, the audio is constantly stuttery on both devices.
Switching between sources, for eg between Spotify and Tidal causes all kinds of issues.

Generally, I'm just seeing a lot of black screens and loading screens and pressing buttons that won't respond and the whole experience has got a hell of a lot slower.

The basics, like just using Spotify/tidal connect work generally ok when I'm not trying to switch between sources or use multi room. It's still pretty slow and cumbersome though...

Am I being unreasonable in expecting a paid for product to just work?

I'm not sure if it's down to the hardware. To upgrade all my Rpi's to the latest models would be expensive. What are other people's experiences with this?
I think probably just go back to the free version and do without Tidal for now.

I recently came into some old Northern Electric equipment, and was intrigued by these step up transformers. I'm attaching some pics to show the 4 that I have. 3 of them are labelled as R14849A, and one is R14849AS. I have been able to find a datasheet on the R14849AS, and this datasheet includes information about a number of other variants of these transformers, but I haven't been able to find anything that explicitly talks about the R14849A.

I am wondering if anyone can assist me with determining what these A variant transformers are. I had originally thought they were basically the same as the AS, but I'm not so sure now.

I've attached the only spec sheet that I've been able to find. Any assistance with this is greatly appreciated!

Hi guys ,
Are these worth listing for sale to the audio diy guys ?

Unused and some boxed .
Came from an ex Royal Navy electronics engineer.

Hello, I have a chinese DAC which has 4700uF for AK4499 chip, driven by an op amp. Supply voltages for op amp are +/-11v. Output voltage of the op amp is 5v and 4700uF. The writing on it is erased. What op amp can be that drives 4700uF? Can it be LME49720 ?

A classic story : playing live music next to the bar ( with the mixer right under it ). A guy did a bad move : a full glass of alcohol with orange juice fell right on the mixer. After an extremly unpleasant sound experience made of BZZZ, Biouuu Bam !
But surprisingly , the mixer handled it and we went to the end of the gig. Back home, I found out that 2 of the 10 track of my soundcraft were dead silent.
I would be very happy to have them back , so here I am asking for some help and advices. Anyone any ideas of what component would be faulty after a fresh drink ?
Both the line entry and the mic entry are not transmitting any sound to the master fader. And to me , the liquid seems tah had been spilled on the preamp part of the board ( next to the plug, upper part of the console ).
Any one ever had that kind of trouble ? Thanks in advance to any helps from you guys;
I upload the elecrtonic scheme, pictures will come soon

Hey,
I’m considering the purchase of a Rega Apollo cdp. It’s used, I’d be the third owner. Here’s the listing:
https://www.usaudiomart.com/details/649886714-rega-apollo-cd-player/
Looks decent, thought’s?

1) Does anyone know the specs?
2) Did anyone ever make aftermarket transformers? If so, who?
3) Did anyone ever find off the shelf part(s) to sub in for a failed high voltage winding? If so, what?
4) Does anyone actually have available stock?

Thanks.

For sale is the only set of Cosyne Unity Horns in the world that were built by Bill Waslo.

I bought them for $500 but spent $1000 picking them up, and I'm looking to recoup what I paid for them. The speakers are for sale for $1500 for the pair.

The bass drivers in the Unity horn are no longer available. If I'm not mistaken, the only way to build these Unity horns would be to find the woofers (which are no longer available) or redesign the crossover.

I rented a set of Danley SH-50s in 2015, and I liked them so much that I offered to buy them. The owner of the Synergy Horns wasn't interested in selling them. So I bought the Waslo Unity horns instead, in 2019.

These were my reference speakers for about two years, but my wife banned them from the living room. (They're BIG.)

I'm located in a suburb of Las Vegas. These are BIG speakers; when I bought them I flew out to pick them up and then drove them to where I live. In order to move them you'll need a fairly large SUV or a pickup truck. I actually bought a SUV to move the Synergy Horns that I rented in 2015!

Here's some info on the speakers:

https://www.diyaudio.com/community/...or-sale-built-by-the-great-bill-waslo.332379/

I bought a faulty Akurate Kontrol 1 ethernet preamp.
I managed to fix the XLR inputs but I have a problem with the third input, the smd 38w transistors are defective and must be changed.
Does anyone know what FET model they are? It is said on the internet that it would be BSS138, is it true? can someone help me with this information?
I would like to repair this preamp
Thanks
Regards
Gabriel

what do you think ?


component placement looks like the original
aliexpress link

I am using only Equalize APO.
If it is set based on a desktop, there is no limit to the number of tabs of the fir filter, so I always avoided purchasing minidsp's dsp.
But I became curious.
Usually, minidsp has a limit on the number of tabs of the fir filter and a limit on the number of IIREQ.

However,
PC --- Minidsp --- Speaker, Sub whatever

Does using additional FIR filters on Equalize APO apply to all when the basic crossover, delay-adjusted 3 channels (assuming 2 speakers, Sub) are played on the computer in Minidsp?
If that happens, I will buy it right away regardless of the tap limit of minidsp.
As a person who enjoys the process of optimizing the phase using the fir filter directly, I don't want to use the Dirac of minidsp, and I enjoy using the 65536 tab on my PC.

If anyone is using Minidsp, I'm looking for someone to test if what I'm worried about is actually possible.

Greetings!
The title says it all.
Looking for recommendations on standard 19” rack mount chassis. 2u or 3u height.
Can order 3 at a time, but not 50!

Thanks

Hello everybody 🙂

I have a pentode (triode connected) in a choke loaded cathode follower configuration ...where do I connect G3 (the suppressor grid)

1. Leave it / NC
2. Tie it to the plate/anode
3. Tie to the cathode
4. Zenner bootstrap it to somewhere (details?)
5. something else

I am wary of trying to build my own power supply for various chip amp and discrete amplifiers and I was naively wondering if I could use a fixed 13.8 volt linear power supply 10 A, such as:
https://www.velleman.eu/products/view/?id=420118

Would it give enough noise free power for various designs like the LM3886 or ESP 3A. Thank you for any help.
Grenny

New unused pair of Hashimoto A-305 intertage transformers. In factory boxes with tags yet to be fixed to transformers. Brand new condition.

Transformers are in Australia from where the will be shipped very securely

Price for the pair (excluding shipping) is AUD$1250 (approx US$840)-excludes shipping. If you have a sensible offer, feel free to pm me and maybe we can agree on a figure.

Hi to all,

Im looking for a high power (100W+) tweeter that has high sensitivity at ~20KHz. So far my best find is DS18 PRO TW120 which, according to the website graph, puts out 105db at 20KHz; but its a 60W driver so not very powerful. Other considerations are secondary (sound quality, impedance, size, etc). I simply need maximum SPL at ~20KHz.

Thanks

Does anyone have a link to Nakamichi PA-1 schematics or have one in a pdf file? I'm afraid to pay to download any nak manuals because I've got bitten a couple of times by companies that sent download Nak service manuals on items during that time period without schematics. I was unable to get a refund on both occasions. Thanks for any replies

Hi All I've installed Audison AV 1.1 tweeters in my car and it has a striped red wire, is this positive or negative?

I wired it up as the red stripe being negative, however I've read conflicting reports online as to if a striped wire is a negative or positive.....

Please see attached photo of my wiring.

I am still managing with a Behringer UB 1204 mixer - a throwback to my almost penniless days! I have now built a system which will easily reveal the difference in sound quality between a cheap class D and a good class AB amplifier. I have not tried any other mixer yet, but Allen and Heath come highly recommended to me, such as the ZED 12 or 14.
The question being is the modest investment to try to improve sound quality worth it (at the added cost of extra weight and larger footprint), the mixer being used solely for line level volume control of recorded music and overall output level, with no EQ or microphones used.

Hello everyone,

I've been a nerd as long as I can remember, prone to tinkering and taking things apart to try to understand how they work and determine if they could tweaked to better suit my tastes. As this inclination has driven various project ideas over the years, this forum has come up more than once in search results when doing research for the various music electronics projects that have interested me. The information and discussion here has often been informative.

More recently, I have been lurking for a bit, reading a few threads as part of my research for a solid-state guitar amplifier idea, and figured I would eventually have questions for the various members with more knowledge and experience than myself.

I am still looking through the forum hierarchy to familiarize myself with it. Would my various questions, and discussion about my project and design ideas be better suited to Live Sound > Instruments and Amps, or Amplifiers > Solid State ? Or would perhaps a master project thread be better suited to one forum (Instruments and Amps?), and various sub-discussions about sub-sections of the project (power supply, preamp, output section) belong in threads in the various other sections of the forums?

Hi. looking for at least eight pairs. anyone?

Burt Bacharach dies at 94. BBC CNN

A long, long time ago (I know, because I found my posts during construction) I built a pair of the 31 inch Jx92s transmission line speakers. I didn't have any measuring equipment.

They never excited me. No bass.

Fast forward nearly 20 years. Measurement is easier, and so are my finances. I just bought the Dayton Audio DATS v3, and measured the impedance of the speakers (free air).

Hello! Fs is almost twice what it's supposed to be? (95 Hz instead of 50 Hz). Pull out the second speaker... same thing. Other parameters are nowhere close to spec.


OK... I have a pair of Tang Band W3-881s hanging around. Listed Fs of about 100 Hz... and that's what I measure.

Other parameters are at least close to spec.

So - what have I got going here? Is my measurement technique off? (Yes, I calibrated the DATS.) Did I get a bad couple of Jordans? Any help would be appreciated.

Mike aka Cheesehead

The 'T' bass circuit is attached in open baffle form.

A first construction using the values shown will give an idea of its capabilities.

The 2x 470uF (low ESR electrolytic) capacitor tunes the choke to the baffle/rear reflection peak which can become obtrusive around 100-120Hz. This can allow an OB to be moved further back into a corner. Try different capacitor values to adjust the 'cut' frequency.

The cut runs from around/above driver Fs and becomes maximum at the baffle/room corner SPL peak frequency. The resistor in series with the capacitor controls the degree of cut at this frequency.

The choke controls the voltage step-up which arises below/around driver FS where the driver impedance becomes high, and often fails to return to nominal at low audio frequencies. The choke value can be increased to reduce the boost frequency, but this depends on baffle (U/H frame etc.) size. It is the slope with respect to roll-off which is most important, not just the boost frequency itself, for this circuit is acting in series with the driver(s), and it is the driver(s) which limit the 'boost' capabilities the step-up ratio can provide. Choosing 'too low' a choke value will produce a kinked boost resultant which no longer optimally matches the driver/baffle roll-off. The resistance of this choke should also be low to allow LF 'voicing' via resistor adjustment. If the choke does not have a low resistance, then the resistor in series with it may be omitted.

The resistor in series with the choke plus the resistor in series with the capacitor together control the degree of boost/cut arising to balance the first half cycle transduction losses against driver resonance derived SPL increase. There is an initial phase coherent series choke induced boost to counter driver subtraction of first half cycle energy, which becomes stored within the suspended cone and contributes towards resonance, followed by damping due to the series tuned C+L input circuit which limits continuing energy input into the loudspeaker system at its resonant frequency. Resistor values which are too low will provide a response with too much first half cycle emphasis - hence values should be individually selected to suit the driver cone mass, baffle form, Qes etc., also to suit personal preferences, because a slightly over emphasised boost might actually be preferred to compensate for some unavoidable loss at the very lowest of reproducable frequencies.

The line transformer may be between 250 and 500VA, between 2x 18V and 2x 40V depending on driver choice, and with its mains voltage primary left OC. The lower ratings would suit one or two Aplha-15As in parallel, the higher ratings larger Pro drivers. Of most importance is obtaining a transformer with low secondary winding resistance, which generally means toroidal types.

The series output choke should be chosen to suit the selected LF driver; 2mH being shown here as a mid value starting point. Its value may be lower with parallel drivers, higher for those having good MF sensitivity, or may even be omitted with drivers already having significant voice-coil inductance.

The 10uF in parallel with the output choke makes it act like a parallel tuned circuit to introduce roll-off in the typical 1-2kHz breakup region. The final series connected R+C components form a Zobel to counter driver impedance rise with frequency.

The driver is your choice. I have had feedback of the circuit working well with several different types.

The amplifier MUST be a SS NFB type with good damping figure. It should be 4 ohm continuous rated for use when this circuit drives an 8 ohm driver on an OB, and 2 ohm continuous rated when two 8 ohm drivers are driven in parallel. If of sufficient quality this same amplifier may also feed the wideband driver via a series capacitor, say 47 to 220uF, though with a damping resistor connected in parallel with the wideband driver voice coil, say 8.2 ohms accross an 8 ohm nominal driver. Once the wideband driver has this damping resistor connected it is easy to reduce its sensitivity by inserting a resistor in series with the capacitor, say 2.2, 4.7 ohms etc., maybe with a 470nF to 1uF in parallel with the series resistor to maintain overall balance if a supertweter is not being used.

The T-bass circuit may also be used for IB too - between amplifier and crossover though without the series output choke. The kind of energy balancing AF response this 'T'-bass circuit produces *cannot be matched by EQ*, because EQ does not act with the loudspeaker during waveform time.

Cheers ........ Graham.

I acquired a Definitive Technology BP7002 speaker with a humming subwoofer. I observed a 120 Hz tone coming from the sub amp outputs when power was connected. I attempted a repair by replacing the two main power capacitors, as well as four small capacitors near the voltage regulators (see circled caps in picture). After replacing these caps, the amp buzzed loudly and the output signal was "all ****** up" (see scope picture).

Obviously, I screwed something up. But I'm not sure what kind of mistake would lead to this result. I'm about ready to abandon the repair and replace the amplifier, but I wanted to get some input from those more knowledgeable at least.