Full size MAME Arcade cabinet build, that will also double as playing blu-ray movies. Started with intent to repurpose very old auto components/amp, but I need to pivot to using full range, and a much more efficient amplifier/speakers. I do not want to have a powered sub, so will probably need at least a 4-5 inch speaker. Will also likely be powered by a not yet acquired simple 2-channel amp board, like the Dayton KAB-250v4 2 X 50W

Any suggestions on a good full range that would have a decent amount of bass? I have been out of the building game for some years now, and never really tried full range designs before. I will be putting a new baffle panel, so will not need to use existing. I also would not be averse to constructing a sealed enclosure behine the baffle for each driver, if that turns out to be necessary to get proper bass response.

I know the HiVi B4N's could be an option, but haven't any experience with using them full range, without a tweeter.

Hi All,
Please listen to the recorded mp3 file : I play a pure sine wave (852Hz) . As I turn the level up, an strange noise apears. I have no clue where the problem is. My monitor is SC307 which uses SMPS , DSP and Class D amplification. Any help would be appreciated

HEC amplifier topology created by Bob Cordell. I'm interested to make simulation using this topology.
It used 24VDC PSU and OITPC compensation that created by Dadod.
Output stage is simple using double emitter follower with driver bootstrapped. Using small transistor in driver,
make loop gain higher because their high hFE.

Any suggestion are welcome.

Hi I need a replacement
Sp1587 driver for KEF q500

Attaching pics of amplifier chip number

If someone have any info regarding the wattage let me know thanks

I came across an issue where a spice model isn't made for a part (the one in question is the TPA3255). I'm not really trying to do any distortion measurements as much as just checking for signal integrity from input to power stage. Is there a way to simulate a chip amp like that using the universal op amps? If not, is there a way simulate the power uplift from the output stage? (I was also considering just doing a simple transistor class A or something just to complete the simulation, but I figured I would ask just in case)

The hard dome says "When I'm surrounded by a waveguide, I am smooth and can control my directivity"


Reference:
SB26CDC in custom 6" WG by @augerpro



The ribbon tweeter says:
"Really? I don't need a waveguide to be smooth or to control directivity. And I can be heard from all around"



Reference: Fountek Neo CD3.0 datasheet


The compression drivers says "Well I may not be as smooth, or play as widely as you two, but I'm far more dynamic"


Reference:
Tymphany DFM-2335R00-08 in SB Audience H225 90°H x 70°V constant directivity horn.



The soft dome says "Well I may be a bit rough around the edges, and I'm not as sensitive, but people have accepted me just the way I am"








Reference: SB Acoustics SB29SDAC centred on a 8" wide x 12" high baffle

edit: correct SPL responses for 2.83V @1m, clickable polar maps for comparisons, example HF units explicitly named

I am planning to build and LCLC PSU filter for a tube PSE amplifier, and I am debated on 'how good' capacitors I should use in each position to achieve the best sonic performance.

My though process:

C2 is connected directly to the anodes, so the current across it is characterized by large/steep swings and the same frequency of the audio signal, hence I want a high performance capacitor in that position: most likely a high grade electrolytic capacitor in parallel to a film one.

On the other end, C1 current swing frequency is limited by L1/L2, hence my deduction is that any decent capacitor should be good in that position.



Any opinions?

hi.
i am looking for these toshibas and the KSA.

also maybe someone can provide FQP3P20 and FQP3N30 instead of toshibas?

primary i would need a matched quad of thoshibas.
secondary i take also 2 octets of the FQP‘s instead if toshibas are no option…

i appreciate the help of the pros here.

regrads from vienne

Hello,

This is my first topic in this forum, my name is Jan, I live in Germany and I'm interested in audio circuits building mostly Headphone and Phono Preamps the last years. I often use tubes, my goal here is to use technology from 70 Years ago and build something that performs on a level close to modern circuits.

My last project was an Phono preamp using INA849 instrumentation amps in the input, ECC83/12AX7 tubes for the LF equalization and OPA output stage. The circuit around the ECC83 was “classic”, a feedback loop was limiting the gain to 10dB in the HF range, at 20Hz the Gain was 30dB. The highest harmonics (K2) with 1.55V output was around -85dB, measured with an AP ATS-2. Not bad for tubes.

I recently found a real treasure, 2x EF12 NOS Tubes that have been build by Telefunken before WWII. I really think about using them in a phono hybrid circuit again using OPAs in the input Stage (AD797 instrumentation amp) and do all the equalization in a circuit around the EF12 where noise is not an issue. They will be in a shielded case because unfortunately the cathode is connected to the shielding of the tube which is basically an antenna.

My goal was to improve the performance of the ECC83/12AX7 circuit. The output of my old circuit is limited to around 5V, after that THD is increasing. Typically for such an circuit, THD is rising with higher output levels.

So I was simulating OPA circuits, really good results I got with the HDAM design. (HV+ = 150V, V+/- = +-24V) To my surprise, using tubes and transistors in the differential amps is not really an issue. Sure, the offset is extreme because of the unbalance in the input stage, many Volts. But with capacitor coupling (an using caps in the feadback loop deceasing gain to 1 at DC) this is not really an issue. To my surprise in the simulation this circuit reaches around -96dB distortion (mostly K2) @ 5V output in 1kOhm. Using 2 tubes in the diff. Amp does not really improve things here, THD is around the same. I'm not sure how this will perform in real life, the tube could be better in the simulation than in real life. For sure this circuit has some problems, if you power the circuit, output will rise close to the V+ rail until the tube is heated. Stability is really good, circuit is unity gain stable with phase margin > 60°



Would like to hear your opinion! My feeling tells me I will get trouble because of the Tube/Transistor combination in the diff. Amp, I was surprised how good this is working in the simulation.

Thanks!


Best regards,
Jan

Good evening, I want to make my first contribution since a lot of information has been obtained from this forum that has helped me repair some equipment.
Regarding the topic about the mosfets with their numbering erased, I have found a xion brand amplifier with the code A4 and the curious thing about this one is that they did not completely erase the surface of the mosfet, leaving a small detail that I now put in photos
When I dedicated myself to researching on the Internet, I found a page and brand of the possible company that manufactures the type of mosfet. I cannot guarantee that it is the only company, but when reviewing the stock, some values agree or are close to those most used by common brands of the same. form attached page link and make your comparisons I hope the info helps and does not affect anyone

https://wxdh-semi.en.made-in-china....nt-Mode-Power-Mosfet-DSG059n15na-to-220c.html

Although at the moment it would be impossible for anyone other than a company to acquire these spare parts, at least there is data to use and compare with those of other brands and look for a possible substitute.

sorry, I used google translator

https://www.ytaudio.com.hk/brands/product/204/

• 3rd generation twin-Ribbon technology
• Excellent vertical and horizontal pointing characteristics
• Parallel multi-wiring OFC transformer
• Improvement horn dispersion aluminum front plate
• Highly concentrate magnetic field neodymium magnet system
• High power handling

Lightly used, Asking 450USD include posting. n Paypal Fee

I did a bunch of experiments with crossfeed headphone stereo perception, using Chord Hugo crossfeed function, foobar2000 Meier crossfeed plug-in, and more recently a classic crossfeed circuit (Linkwitz-Chu Moy). I was able to achieve stereo sound, depth perception with singer/musicians/stage in front of me, albeit smaller and nearer than the presentation through stereo loudspeakers. The music separates/delineates more easily and sounds more natural. This effect requires:

(1) twisting the headphone pads "OPEN-WING" so sound comes from FRONT-LEFT/RIGHT (and very slightly above if possible), not shooting straight into ear canal; headphones with 2-degrees-of-freedom work best
(2) EQ DOWN both trebble and bass for a realistic sense of distance, but compensate for bass-loss due to pads not being sealed (try hand-cupping ears or draping flaps over the gap as in picture)
(3) time-delayed crossfeed to opposite channel (I conjecture that additional lower bass delay would be better)

Headphone Stereo Test Prep Music uploaded to China's bilibili (click triangle to play)
LISTEN WITH HEADPHONES "OPEN-WING" foobar2000 Meier Crossfeed set to max, EQ'ed https://www.bilibili.com/audio/am33118121?type=7
original/control for comparison purpose only https://www.bilibili.com/audio/am33116224?type=7

I hope there is interest in this topic. I have found a few circuit diagrams. Crossfeed miniDSP anyone?

I saw a video of NWAS 2018 where Scott uses an Spreadsheet to estimate the final response of the speaker in the room depending on position.

I have a pair of Mark audio CHN 110 and I would like to use this spreadsheet to estimate the response of the many speakers projects in the mark audio website to see what fits the best in my room

Somebody know where I can find this spreadsheet?

Link of the video in the moment Scott is talking about the spreadsheet:

Login to view embedded media

Thank you

Hello folks, I got this amp and someone had messed with it before. Looks like they tore off a transistor and I cannot find a service manual to tell me what it was. Can someone help me make maybe an educated guess? It is the one circled on the left of the first photo. I am guessing it is the PNP version of the CR533 such as a 2SAR533D but not sure. Is it possible it is another NPN like the CR533?

Hello folks, I got this amp and someone had messed with it before. Looks like they tore off a transistor and I cannot find a service manual to tell me what it was. Can someone help me make maybe an educated guess? It is the one circled on the left of the first photo. I am guessing it is the PNP version of the CR533 such as a 2SCAR533D but not sure. Is it possible it is another NPN like the CR533?

Greetings friends. I've found myself at the early stages of planning a DIY audio community and have been tasked with finding a suitable amplifier for a DIY kit to be assembled by newbies, and I am here to ask your advice.

I am looking for a PCB-based circuit for a power amplifier, an AB1 Push-Pull amp using EL34/6L6 output tubes and something other than those hard-to-find 7199 to drive em. I would prefer a cathode-biased circuit for simplicity, but will accept arguments for fixed bias design. Above all, I am looking for a DIY project with a high rate of success, so we can bring more people into the glorious world of Tubes.

Any ideas, projects, advice, or warnings welcome.
Thanks!

Will

I purchased 2 sets of these boards in October, populated and used them for about a month until I completed my own custom soft start control board. Purchased and built 2 sets as I have a pair of Aleph J's in bi-amp mode. They are ready to use!
Great price: $60 a pair (1 soft start, 1 speaker protect). Once you let me know your location, I will provide ship cost. I don't charge any extra on shipping, just recovery of cost!

Hi,
I recently acquired from a relative these two old tubes. searching the internet they look very similar to Western Electric 284D or alternative Amperex 211 VT4C?

Is there any experts who can identify these from internal construction. Photos attached

Thanks!

Not seen any posts from PRR since March.
Anybody know anything?

As a follow-up to a recent post: is it possible to apply a VBE multiplier with a Si transistor for a complementairy output stage with Ge transistors?
(See example).
R2 in the circuit must be of a very low value to avoid a melt down of the Ge's. But is it 'controllable' with a certain adjustable value of R1?
Wrapping up: what would be the lowest possible multiplied Si-Vbe?

Answers not needed:

• how Vbe multipliers work (explanations, doubts of my knowledge about this topic)
• to have things thermally connected / frequency related issues / driving or loading issues
• &c

Just: if, how, what can, what not. Nothing else.
It's theoretical.
Practical solutions from the past are appreciated, as long as they fit the scope.

Thanks Andersonix for your very single example.

Hi Sony VFET experts , I need help determing the rank of 3 vintage Sony VFETs found inside a part unit of a high end vintage Sony VFET amp the VFET is shown in the pic, your kind help will be greatly appreciated ! Thanks! And a very happy new year!🙂 the 3 VFETs are all marked SONY 2SK60 A580, I could not find any info as to what rank they might be .

By trying to detect why a Philips GM6012 millivolt meter does not work, I have to dismantle all the shields on the outside.
Does anybody know how I can do that? At this moment I only could detached the backside of the GM6012.
youtube did not gave me any hints.

Hello fellow DIYers !

With much help from the fine folks here I begin to master the design intricacies of my vintage integrated amp's MM/MC phono stage. The amp is 30+ years old and the only schematics I could find online were for the revision 3 of the design, whereas my unit is rev. 1. When trying to match the PCB to the schematic there were areas I couldn't make heads or tails, and it turns out there's a major difference on the implementation of the output stages.

Rev 1 implements a cascode stage while Rev. 3 doesn't; of course in both cases the output (TP13) is still taken off the center of the push-pull stage. See below.

Rev 1:


Rev. 3:


So my question is, why use a cascode at all if the output is not taken off the top transistor's collector? The top collectors are directly connected to the supply so there can't be any output taken there. My guess is to mitigate power dissipation in the output devices since the supply voltages are relatively high (The phono stage shares the same regulated voltage as the power amp section). But if it is for this reason, why drop it in Rev. 3, since that version has the same supply voltages? Simply to save a few transistors I guess... Or are there other advantages I don't understand? A cascode provides extra input to output isolation, but only if the output is taken off the top collector right?

Note that the second stage's output has the same cascode arrangement but with extra filtering capacitors between ground and base of the top transistors :



Thanks in advance for any insights, and let me wish you all the best for 2024, good health and successful projects!
- Joris

I have always been fascinated by magic tricks, some I can explain but some are a complete mystery.



From the 70’s onward, I played keyboards in the north of England working men's clubs, providing musical backing to all manner of variety acts.



On this particular evening I was at a club in Castleford, and the artist was Johnny Burnette, A one legged, close up magician I had worked with on many occasions.



I arrived at the club to find Johnny showing a magic trick involving a pound coin, to Alan, the drummer. I was at the opposite end of the dressing room (about 20 feet long), getting changed. After about five minutes of magic, Johnny announced it was probably time to get ready for the show.



Where is my pound coin, asked Alan. Oh, I seem to have lost it, said Johnny. He looked at me and enquired what time it was? I slid back my dress shirt sleeve to look at my watch, TO FIND A POUND COIN SLIPPED UNDER MY WATCH.



HOW? He was never within 20 feet of me. A one legged guy cannot spring across the room. Not hypnotism, I have worked with many hypnotists, and it has no effect on me.





To this day, I am still mystified.

Hi, I want to make a relatively compact speaker to listen to music around my apartment. I plan on using two drivers, one on each side of the front of the speaker.
What would be a good, full-range driver for this?

Hi friends,

Couple of weeks ago I bought this nice looking TB drivers.
My plan is to put them into a simple BR cabinet.
I Also like to reuse my old Stands that I kept from an old project.

Here 11,5 ltr Net.
Poort tuning 55Hz.

Anyone experience with this driver?

Hereby the first concept.

As the Title suggests, I'm looking for a replacement SMPS for a Linn Classik Movie Di.

It looks like this and the only references on the board I can find are 'DESIGN: IW, AW 08/02/02' and 'PCB254/L4' : -

Hi all,

After several years of successful R&D for our loudspeaker company (A for Ara), we have a rather large haul of drivers we didn't end up using in production models.

I'd like to pass these along to the fine folks of this community.

Does anyone want to come visit and take the entire lot away for a very reasonable price? We are located in upstate New York (2.5 hrs from NYC and Boston).

Please reply here or email me directly: db@aforara.com

I'll work on a more exact list of what's on hand. Everything is neatly stored in boxes.

Someone with a bit of patience could easily purchase this as a lot and make a couple grand piecing it out for sale.

OK!
Rob

Turntables: VPI Classic 30th anniversary model, Collins, more (no Garrards, sorry!)

Here's a partial list of the drivers:

Hello folks!

I've scavenged a working power transformer, output transformer and speaker from a very dead Philco 1224 Gramophone, and my plan is to build a small guitar amp using those as the core. This is my first attempt at design, so I've cobbled together a best-guess schematic which reinvents as little as possible. In that spirit, the rectifier, filtering and output sections have been lifted straight from the original schematic:



For the preamp, I've settled on a single-jack version of the typical Fender input, cascading a couple of 7F7 tubes, and thrown in the most copied tone stack of all time for good measure. This is what I have so far - I struggled to find appropriate symbols for all the necessary components, so please excuse the obvious substitutions:



The matching BOM:



I want to start working on the component layout, but I suspect there are errors aplenty in the schematic due to my inexperience. I'm hoping that some more experienced people are able to look at my work and suggest improvements to the general topology and/or component values before I go further. Is there anything glaringly obvious about what I've got so far which you would do differently?

As I progress through the build, I'm also putting the source files up on Github too: https://github.com/akhumphrey/1224-amplifier

Hi all. First time poster here so if I have this is the wrong section please accept my apologies.

I'm not a DIY electronics person but I do enjoy dabbling in simple projects from time to time. That said I found a Logitech Z-5300 system at a local thrift store. It had all 5 satellite speakers and the control pod so I grabbed it up figuring I might be able to find just the sub on Ebay. Well I couldn't find the sub/amp combo for a decent (cheap!) price but I did find a working Z-5300 amp without the sub. I paired it up with a sub I already have and stole the 120v transformer from another cheap Logitech sub found at the thrift store.

Now as I am trying to hook things up I'm unsure of the proper connection to the transformer. As Wendle states in the thread linked below there are three sets of wires coming out of the Z-5300 amp. Two speaker wires for the sub, 2 power mains that go to the transformer, and 3 wires that go to the other side of the transformer. (These would be the longer green, blue and black twisted set in the photo Wendle posted.)

The problem is that my transformer only has 2 wires for the secondary side of the transformer, not three like what is coming off the amp. So I'm unsure of how to wire these up.

Do I just connect one of them to a single wire on the transformer and then connect the remaining two wires to the remaining single wire on the transformer? It's probably a pretty simple thing, but I'm very much a novice at the electronic side of DIY projects, so any help would be greatly appreciated.

Thanks!

http://www.diyaudio.com/forums/chip-amps/135930-logitech-z-5300-without-remote.html

Hello together, I am selling 2 KEF SP1587 (coax from Q100) including cover ring. Technically the drivers are very good, see impedance measurement (impedance measurement was redone especially for the sale) and visually they are very good. They were only in use for about 1 year and have been in the cupboard since then. Price will be 200,00 Euro alltogether but is negotiable. Shipment inside EU will be extra 16,00 Euro. Best Regards Johannes

Normally with phono amps a regulated or choke filtered B+ is advised but here is a what if.

Let's say one uses a decent RC filtered supply and uses a plate choke load on the first stage. In theory the first stage noise contribution is the most critical and high gain is desired there. Of course an active load would be another reasonable option I think.

Would the PSRR and increased gain be sufficient? Something on this order. R load used on second stage to allow DC couple to CF.

Unfortunately I know only this brand, which have realized this approach to obtain a lowest value of parasitic noise/sonic radiation (still an unwanted effect owing the use of usual MDF pressboards instead sandwich parts for chamber cabinet resp. box enclosure). - go also to
https://stereonomono.blogspot.com/2022/11/roksan-darius-loudspeakers.html
for further information.
Are there also other brands with this kind of fixing the speaker envelope ??

Also the kind of tweeter mounting with springs is of interest (never seen before and thereafter at other manufacturers).

Thank you for advices.

P.S. - for your information:
Also very special was the outdoor unit for the crossover network.
This loudspeaker was equipped with custom made transducers based on follow good known drivers:
1) KEF B200
http://www.zenn.com.sg/Marketplace ima…ch/KEF_B200.JPG
TL Links
2) Seas (similar to K26FX, but only single magnet, supronyl-cone+Ferrofluid)
either
http://www.seas.no/images/stories/vintag…h297_25tnft.pdf
or
http://www.seas.no/images/stories/vintag…h253_1_dome.pdf

Update on a post further down....... now trying to decide between teh Anarchy 7 and the Wavecor SW182BD03/4, or the Dayton Epique 7"

I'm designing a subwoofer for my specific scenario... Several drivers seem to fit the parameters I need.....and model a very similar frequency response in a similar ported box, etc. Trying to figure out if there's something else I should look for/think about before choosing between drivers.

I'm looking for a subwoofer that is...more "musical" and not about punch/shaking the house..... and won't be played at an extreme volume ever (I have downstairs neighbors that I don't want to constantly offend).... I just want to round out the frequency response in my room, more bass than the Carmody S2000 kit will provide. I'd like good low frequency extension, but at relatively low volumes, and I have box size limitations. (SAF, etc)..

Is there something else I should pay attention to that WinISD modeling wouldn't show when choosing between drivers?
For example, I'm looking at the Dayton 6.5" paper cone sub, or the Anarchy 7 aluminum cone sub, and other similar size sub drivers, like the Dayton Epiques, etc..... Is there some other parameter to pay attention to, like cone material? Or magnet size, basket, etc? Or will WinISD lead me astray? (Modeled 40hz performance of one driver vs another won't be accurate, etc?)

Thanks for your thoughts!

-Nate

So I’m planning on building a system along these lines for the horn section but instead replacing the 14” woofer with a pair of 8” drivers for an overall narrow presentation. Trying to figure out what JBL did here with the horn…..is it just an existing biradial modded and turned on its side?……JBL says 60 degrees horizontal in their literature but looking at the lens, how’s that possible?

Anyone have any data or points to share?…..I know there’s a member here who has them and I’ve auditioned them a while ago and remember them being really dynamic and engaging

Hello,
I need a switch Support or Bezel that allows the switches to be recessed inside of the case, here are photos of that part:



This type of Switch Support/Bezel was use in all the Nagra IV line of models but also in equipment of other brands,
here is a photo of some DI Box supposedly made by Helios (closed down in 1979) that used the same type of assembly:





Does anyone know any info on these parts?
Sources for it?
Or any other equipment that might have used them?

Thank you so much for your help

I’m pleased with the big reduction in hum level by removing the original built-in transformer and bridge rectifier and then using a toroidal transformer with an Ebay Chinese rectifier/capacitor board. It required a bigger box too. Hum level is so low as to be inaudible now even though I have increased the overall gain to give an output similar to CD. I also changed the original mica cartridge load cap with a polystyrene one and added a second switchable one to sum to it if required on each channel. Also, this circuit needed DC blocking caps on the output which at best is around 100mV...this value does vary quite a bit with different samples of LM4562. I have also included a series and discharge resistor on each side of the O/P caps as seems to be the norm. Sound quality really is superb and totally transparent using my Ortorfon VMS 30 Mk2 (fine-line stylus). The transformerless late board is now available shown below

Hello to all. Having built several rather sophisticated horn-loaded systems, I've recently heard the Voigt Pipe speakers. Yes, I saw that video, too. And now my hands are itching again. And this time, you guessed it right - I would like to build the Voigt Pipe. In order to overcome the inherent weakness of full-range speakers when it comes to very dynamic passages, I decided to add a tweeter instead of relying on the wizzer. Initially, I was going to use the Tang Band W8 1808. But then I thought to myself, If I'm not using the wizzer cone why not use a comparable driver without one? So, here's the questio: what 8" driver would come the closest to the venerable Tang Band W8 1808 but without the wizzer cone?

Hello everyone,
Just joined the forum! I live in Montreal, Canada ❄️! My lifelong passion for audio has taken me from creating (repetitive) electronic music in the past to enjoying vinyls (with by a glass of whisky 🥃 even better). I've always configured various media players, using platforms like xbmc, Moode Audio, RPi+DAC etc but now willing to take it to the next level (with your help please!).
Big fan of SomaFM DefCon during long nights of DIY'ing 😎 Looking forward to the discussions.
Cheers!

Offer something reasonable. Shipping costs (from Finland) are added to the sum.

Items for sale:

1) First Watt Power supply Cap banks: Dual mono / fully built with Abico connectors

2) First Watt F6 boards designed by late DIY member Georg M. / made in Finland by a quality company

3) First Watt F6 fully built PCB with Jensen transformer /Toshiba JFETs / IRFP Mosfets / Simlic & Wima caps

4) Pass Labs B1 front end / built - only connecting cables needed

5) Toroidy Tranformers 50€ / pcs

a) 2x24VAC 600VA (primery 2x115V)
b) 2x32VAC 600VA (primery 2x115V)
c) 2x50VAC & 1x18VAC 520VA
d) Triadin 2x24VAC 50VA (18 euroa)
- details in the pic

Long time lurker, finally decided to say Hi.

Name's Andrea. I'm an electronic enthusiast from nort-east Italy, I did build myself several kits and other mixed projects, and always found lots of information here.

see you around!

Tuning / tweaking of a Chinese BTL mode TDA2003 Mono amplifier.

It has some mediocre working Bluetooth 2.0 which I do not use.

If Bluetooth is needed I recommend a more modern 5.0 Bluetooth preamp.

I put on the electrolytics 0.1 microfarad foils in parallel. Also same size power decoupling foils between legs 3 and 5 of the TDA chips.

100picofarad on the inputs between plus and minus against oscillation.

There is an smps power supply I left untouched.

I put 1.3 microfarad and 4.5 ohms paralleled in line with the 4 ohm loudspeaker in order to attenuate a fullrange driver and to lower distortion by using Esa Merilainens simple resistor method for a bit current drive. More on this on his website current drive info.

For sale a pair of verry good regs for class A amps or other hifi builds.This are good for constant 10A of current and 20A on spikes.I buy some pieces positive and negative regs of this ,years back directly from Thel audio germany but today they are not more produced(verry dissapointing).I use this in all my pass aleph builds and they work without problems and with regulated psu you have way lower noise floor and much more blacker background.In music you have much more details,better and faster bass section and verry silky high section.You will become one positive and one negative reg module,so you can build one psu for up to constant 10A of current.The input voltage is from 20-100V and the output you can set by trimmer from 10-90 volts. In last picture you can see my psu for my aleph 6 build.The price I want is 200 eu for both plus shipping in EU!!!Payment by paypal or bank transfer.For more questions plese contact me.

For sale pair module original nade by Hugh Dean from Aspen.Fully working order,I used this last 5 years in my second system power amp.I only have change the input cap on each module for some verry good Mundorf Evo oil 1 uf.Module ready to play,you only need transformer and other stuff.Price 300 eu including shipping inside EU.

I have a blown set of PSB Alpha PS1 powered bookshelf speakers. They popped and died one day when I touched the aluminum volume knob after walking across the carpet with socks in winter. Oof.

They're nothing wildly special, but I like the way they look, and as a tinkerer, I'm thinking it might be fun to get them to make noise again. Most internet folks say it's a lost cause with powered speakers. There's either not enough technical information about the components, making it hard to pair the drivers and crossovers with a proper amp, etc, or the juice just isn't worth the squeeze. I'm not sure. Not having opened them up yet, I don't know what I'll find in there (not exactly easy to open), but could I feasibly turn these into passive speakers, or (possibly) repair the onboard amp and give them new life?

Thanks for your patience. Very new to this side of audio.

Hi all,

Have a blown diode from a Eaton 5PX 2000 rack mount ups that needs identifying.

Similar packaging size to your traditional 1N4xxx rectifiers.

Markings on this diode is

PJ26E
p e c 3049

From what I gather pec is now owned by Panjit but I cannot find any info on this

Cxa1800.1 volume level is chaotic.
When I have the volume turned down it is really loud when I turn the volume up the bass starts chopping it sounds like I got a wire loose but all wires have been checked and all of my splices are solderedand shrink wrapped I have went thru the manual front to back I've removed my lc1i and changed it from low input to high and still the same thing it was running fine but I changed from a cheap $5 line leveler from Walmart and it is the only thing that kinda works. I'm st a loss here talked to Todd at edburg amp repair and he sent me here specifically for papazbill but any help is welcome. Thanks

I like sound synthesizers and there's an on-line "Binaural Beats" generator here https://brainaural.com/

Aside from its intended application, it has a stereo pan function where, according to a provided LFO, it'll sweep a tone back 'n forth between the left and right channels. That tone can be set from 27 Hz up to 14 kHz. So you can take a tone, slowly (say, 1 Hz) pan it left / right and listen to that using headphones.

Why? To see how, or if, your ears work. Mine are like old tires that have never been rotated, 1/2 the tread gone on one side.

2.5 kHz the tone sounds about the same as it pans left and right.

3.5 kHz I'm aghast to find the pitch doesnt sound the same in each ear. Twee in the left, dell in the right. Swap the cups - same thing.

4.1 kHz right hears it, left not nearly as much.

8 kHz on up, only the left hears anything...

10kHz perception of anything in either ear gone.

A discussion elsewhere whether YouTube really do preserve uploaded videos audio content up to 20 kHz, or limits it to 16 kHz spurred my curiosity to look into it, and for the investigation I looked up a few audio frequency sweep test videos and chose the following video for this brief investigation.

Login to view embedded media
All audio files were downloaded directly from YouTube as an incognito user, no external download helper website were used as these services usually convert the audio into MP3 format which degrades the audio quality even further, but also the conversion parameter settings aren't known either.
As for YouTube they still offer AAC audio codec usually with the legacy MP4 video container format, but around 2011 YouTube started switching over to WebM (Web Media, usually used by online video platforms) container wherein the video comes in VP8, VP9 or AV1 codec format, and audio in OPUS codec format.

After having downloaded the various audio files I were able to grab, the files were then analyzed with Audacity, the spectrogram setting was limited between 15 kHz and 20 kHz as that is the frequency range of interest, and the following results were found:

( Each downloaded audio files file-data were analyzed on-line with: https://mediaarea.net/MediaInfoOnline
And the title above each image (codec, sampling rate, bit rate) stems from the data analysis for each file. )

AAC 44.1kHz 127kbs



Opus 48kHz 74kbs



Opus 48kHz 103kbs



Opus 48kHz 171kbs


Conclusion: As YouTube nowadays stream virtually only by using WebM (OPUS) one can consider they do support 20 kHz audio bandwidth.

Disclaimer: As this was a rather brief investigation, the results are presented as is with its limitations, there are much more info on Google Support what audio and video formats and qualities YouTube supports.

Some First Watt stuff for sale on Swap Meet. 👍 😉

Well, I'm certainly not first one to ask Modushop Team is there solution for slim Monoblock case ..........
Anyway , recently I did chat with our Italian friends ...... and thet are evidently willing to do something

Basic idea is to have 4U/400 case, but narrower

Entire package, (hoping they did understood my ZMEngrish) consisting of 3 iterations:


1. first logical iteration is one side having 4U/400 heatsink ( I don't care is it one piece or two) , while other side being blank plate ; you can orientate it by wish, so wth pair having one right and one left enclosure

2. second logical iteration is heatsinkless case, intended for separate PSU ( don't ask, I'm first one thinking of pair of cases per side, just as Demonstration of Force, if not necessity) ....... so penny-pinchers among Greedy Boyz can make one (pair) of mono PSUs and zillion of channel cases, then combine them Till End of Time

3.third logical iteration is both sides having heatsink, so you can squeeze nicely thought elegant Beauty of Amp inside ........ from whichever reason - easier to smuggle by Kerber, or esier to put more of them on shelf ..... or you just like them that way

set of preliminary pictures enclosed, raw finish, not anodized .........

my Vote goes to front plate (as usual) covering entire width, including heatsinks

What ya say ?

Basic dimensions are sorta carved in stone ( zillion Greedy Boyz, zillion and one opinion) so don't bother to change that; what I'm asking now is - what you say for width of front plate ........... and do you have any (useful and beneficial!!) idea to add?

Unification reasons (price for Greedy Boyz) - dimensions of "cage" itself must be the same for all 3 iterations;
Now - I like idea of full width front for case with one and 2 sinks, I like the same for heatsinkless one - when looking them in pair, and I'm sorta ambivalent when thinking about empty space behind wide front plate without sinks; so...... as always - compromises.........

I'm sure Gianluca will chime in, to give you details about width of case ...... I deliberately left that for him



And yes, 'Talians - Danilo Petrucci is first man alive, after having 2 MotoGP victories, also claiming victory in Dakar stage for motorcycles

Go figure; it must be something in the air or water, in Italy

🙂

edit, much later: one thing I did forgot - having base plate for these is also important detail .......

Having recently acquired a QA403 audio analyzer I looked at the linearity of some film caps I have, all ostensibly PP 100nF. I found 3 kinds of distortion profile among them, making me wonder if these are routinely being faked with cheaper dielectrics. The test setup was a divider, 100nF cap on top, 6k8 metal film resistor on bottom. This has a high pass response with -3dB point around 250Hz.

The responses I see from the three types of cap are:





Clearly cap1 is a high-k ceramic cap with high amounts of distortion evident. caps 2 and 3 are clearly different dielectrics, or very different film thicknesses (unlikely as these are all 100V rated). Only cap3 type seems to actually be PP with its very low distortion.

Here are the 3 tested samples, cap1 at top (its poor printing registration is further evidence for this being a counterfeit part):
Since these are all from my 100nF bin I don't have records of where each came from, alas, but its quite possible some are eBay, which would account for the rogues - so now I'm faced with the task of testing all my film caps...

What causes driver surround damage / distortion?
Can it be fixed?
I'm hoping somebody's going to tell me: hair-dryer or steam or some other crazy solution.

Simplest possible 1-transistor power amplifier with THD <1%

The challenge was to build a simplest possible amplifier that would be still usable. With wide frequency range, flat frequency response, reasonably low output impedance and reasonably low, inaudible THD. I am offering the result – the necessary functional circuit part has only 1 transistor, 2 resistors and 2 capacitors. 2 more resistors (discharging of coupling capacitors) and 1 supply bypass capacitor were added to the final circuit. The amplifier was designed for fun, as a circuit challenge, but the necessary condition was it must be workable and repeatable.

The circuit is a class A emitter follower with a BJT power transistor. It has voltage gain close to 1x, so it makes no voltage amplification. But it has current gain, thus also power gain, so it is a power amplifier, though with very low power, if we do not want to build it big with large heatsink. Emitter follower has almost 100% series voltage feedback, so it cannot be called “no-feedback” amplifier. Such qualification would be misleading. Due to this strong negative feedback the emitter follower has quite low output impedance, between 0.1 – 1 ohm, depending on the transistor used and also on signal source output impedance. The drawback of BJT follower is quite low input impedance, for load 4 – 16 ohm and transistor h21E about 100, we can count with input impedance 300 – 600 ohm approx.

The real circuit


Erratum: C2 = 6800 uF

C1 is an input coupling capacitor. R2 is a base bias resistor that sets the idle current of Q1 transistor. Q1 is PNP Sanken 2SA1102 transistor, just for the reason I had them in stock and they fit into my heatsink used for the amplifier. NPN transistor can be used as well in case that all electrolytic capacitors would be reversed in polarity. R4 is an emitter resistor that defines idle current and also limits the maximum current and power into the load. C2 is an output coupling capacitor. R1 and R3 are the discharging resistors to prevent loud clicks when speaker and signal source are connected. C3 is a power supply bypass capacitor. Idle current is set at about 450mA, which makes about 4W idle power loss of Q1 when supplied from 14V. Power supply voltage may be between 12 – 15V. Heatsink used is Fischerelektronik SK409/25, Farnell #4621293.
Edit: C2 = 6800uF

PCB board

The amplifier was built on a 2-layer 87.6 x 60.6 mm FR4 PCB. Produced in China, 5 pcs of PCBs cost 5.00 USD total + shipping cost. Incredible. 2-layer board is only for the reason of reliability, the solder joints would not peel off even if overheated.



Power supply

Due to not great power supply ripple rejection of the circuit, a small sealed 12V accumulator is an option. That's how I started to test it. Then I built a traditional bridge rectifier followed by a capacitance multiplier. As the current consumption of the amplifier is almost constant, the capacitance multiplier is a good choice that grossly reduces PSU ripple.




Setting Q1 idle current

Please have a look at schematics above, Fig. 1.

R2*(IE/(Beta + 1)) + VBE + R4*IE = 14V (PSU voltage) (1)
R4 = 10 ohm and we want IE = 0.45A, so R4*IE = 4.5V; VBE = 0.6V; Beta = 50
Calculate R2 from (1) as 1009 ohm, rounded to 1k
So we have R2 = 1k and R4 = 10R.
The capacitors C1 and C2 are chosen not to restrict low frequency response extension.

Real amplifier sample
Looks like this:





Parameters and measurements

Input impedance ….. 211 ohm with 10 ohm load
Output impedance ….. 0.32 Ohm with signal source with 50 ohm impedance
Voltage gain ….. 0.976x for 50 ohm source impedance and 10 ohm load (speaker) impedance
Frequency range ….. 20Hz (-0.5dB) – 10MHz, not limited by slew rate
Rise time of step response ….. << 100ns
THD at 1V/10ohm ….. 0.2%
THD vs. level and frequency ….. see plots below
Usable output power for THD < 1% ….. 300mW / 8ohm
Capacitive load ….. up to 2uF

Oscilloscope measurements

10kHz square input and output



Fast rising edge of step response, input and output



1MHz sine, input and output



Distortion measurements

THD vs. frequency


THD vs. level


THD 1kHz


IMD 19+20kHz


Conclusion

The project was made for fun, to evaluate what is the simplest but still usable 1-transistor amplifier. The circuit has extremely wide bandwidth, very fast transient response, does not care about complex load or shorted output, has still acceptable distortion. But, it has very low power, in case we do not want to build a massive heater, and has low input impedance, that is best to be driven from headphone output of mp3 player, iPad, iPhone etc. Have fun!
_________________________________________________________________

Important - construction notes:

1st sample built has part values according Fig.1., only C2 = 6800 uF. The 2SA1102 used has Beta = 60 and with this transistor idle current is 500 mA.

Today, on Dec 15 I have built a second sample. Interestingly, the 2nd 2SA1102 has Beta = 151 and R2 had to be changed to 1k8, because with 1k the idle current was too high and 10R/5W resistor would be overheated. With R2 = 1k8 and high Beta = 151, the 2nd sample has lower distortion and better measured PSR. It has idle current of 600mA, just at the limit what can be dissipated with the construction shown in the photos above.

Hi. I have a somewhat different plan for a power supply setup and wondering if there is anything inherently wrong or dangerous doing it this way.

I want to make a external power supply. It will have two transformers. One transformer rectified to dc in the external supply. Plus a second transformer in the external power supply but rectified in my audio equipment. So that part would be leaving the external power supply as low voltage ac. I want to use a multi pin avation plugs to run from external power supply to my audio equipment. Is it OK to mix the ac and dc on the aviation pin cable(4 pin cable 2 pins ac, 2 pins dc)?

Do toroids (toroidy audio grade) need to be a certain distance from the side of the chassis they are houses in?

Does each of the transformers need their own safety grounding point on the chassis or can they be star ground to the IEC Inlet grounding point?

Thanks for any help. I am still a little new to diy and don't want to make any costly mistakes.

Hello!

I'm about to build my first vented enclosure. I decided to use Markaudio CHR-70.3 again, my first project was this, sealed cubes: Cube shaped speakers

Since floorstanders require more advanced woodworking skills and I'm a beginner I decided to build bookshelf speakers, but I would also like to get as much low end as possible. So the bookshelf design can be quite large, up to 50cm height.

I am planning to build the first one(A), Mark 9 from Strassacker, since it's the largest bookshelf design for CHR-70.3 I could find online. How do these two compare?

A. Mark 9
B. CHR 70 Chamagne | Markaudio Slim-deeper bass reflex box

My questions are:

1. I assume the A can deliver better low end?
2. Strassacker site states frequency range (-8dB): 38 - 30000 Hz. How do I compare these numbers to commercial speakers which usually state the frequency range at +/-3 dB?
3. The Markaudio Slim-deeper box states resonance frequency (Fb) 57Hz. How do I compare this number to Strassacker frequency range or commerical speaker frequency ranges?


Thank you!

Hi all,

This is my first post on DIYAudio.
I have a limited understanding of circuits and electronics, but have good experience with Hifi, terminations, soldering, commercial pro sound standards, etc.

I apologise if this question/answer is silly or obvious.

I was hoping to seek some advice to help explain how this kit:
IAN CANADA CONDITIONERPI Ultra Capacitor Conditioner Board for Raspberry Pi - Audiophonics

.....would differ (performance wise) from simply inserting a few 5vdc super capacitors in parallel with my RPI power supply.

I have struggled to find much feedback on this item, and would appreciate your time and insight.

Manual:
https://www.audiophonics.fr/en/index.php?controller=attachment&id_attachment=1363

My goal is to further improve on my RPI4 power supply, which is currently the iFi power x. This supply provided an excellent improvement over the standard RPI SMPS. iPower X by iFi audio | New Ultra-Low Noise AC/DC Power Supply with International Travel Adapters

According to the product specifications the PS has a 1uV noise floor, which is consistent with previous model testing.
Power Supply (8+) Group Test, LPS and SMPS - DAC - Digital to Analog Conversion - Audiophile Style

Thanks

With dynamic headphone now getting more and more expensive,
and the many high bias class A amplifiers around, including two from us,
it is perhaps a good idea to have a protection circuit for headphones.

The difference to a loudspeaker protection is of course the lower trigger voltage level (e.g. +/-80mV DC).
This requires a different treatment for the DC sensing stage.
Here is our solutions.
Works first time as intended. 😉

http://xen-audio.com/documents/SHPP/XEN SHPP V1.pdf


Patrick

.

All other things being equal: 8" Driver, 20 litre cabinet, which system offers the best performance.

Hi everyone.

For a long time I've been looking for a small class A amplifier around 15 watts to be used as a good known reference when trying out new stuff.
I thought of the good old JLH1969 or a Hiraga. I know both quite well.

But I thought why not try to make my own, which is why I post this thread. I have'nt build it yet, as I have some questions that I hope some of you can help with.
So for now everything is only in LTSpice. I also have to mention that I am not an engineer. I am just curious about audio stuff, and I've learned a lot from this forum.
I have repaired countless amplifiers over time, but designing one is a totally different beast.

So here we go...
Most of this amplifier is quite basic, except for the output stage, which is inspired by JLH.
It is a quasicomplementary bjt design and the outputs are fed from the vas directly. There are no drivers, no emitter resistors, and no biasing circuitry.

The idea is to try feed the bases of the outputs with a constant current. In this case around 10mA. (Based on the KSC5200 spice model's Hfe).
This is done in the vas stage, which is a differential amplifier running at 20mA, sharing half of that to each output device.
I wanted to see what happens when we apply a signal, thereby changing the current balance, which results in a signal on the output.

The amplifier has fairly good data, except for the output impedance, which is very high.
Square waves looks reasonable, distortion is low as long as we stay in class a.

Here are some data. I did these sims twice, once without load, and once with load. The test sims are done with the output coil in place between the amp and the load.
The output signal is taken directly on the amp before the coil/load.

NO Load:
OLG 1KHz ~ 80dB
OLG GAIN 20KHz ~ 69dB
UGLF ~ 2.285MHz
PHASE MARGIN ~ 68.3°
GAIN MARGIN ~ 14.7dB

8 Ohm Load:
OLG 1KHz ~ 67.6dB
OLG GAIN 20KHZ ~ 64dB
UGLF ~ 2.228MHz
PHASE MARGIN ~ 68.5°
GAIN MARGIN ~ 15dB

Slewrate is around 22 ~ 23 volt/uS with 8 ohms load and a 1n cap.

Output impedance is 24 ohms up to about 1KHz and starts to rise from there !

8W in 8R+100n @ 20KHz -> Total Harmonic Distortion: 0.001033%(0.001027%)
8W in 8R+100n @ 10KHz -> Total Harmonic Distortion: 0.000536%(0.000524%)
8W in 8R+100n @ 1KHz -> Total Harmonic Distortion: 0.000110%(0.000000%)

Idle current ~ 1.5 to 1.6 amps. Each output device will dissipate 36-40 watts at ±24V

I am trying to figure out if this will actually work with such high output impedance, since high output impedance usually means the damping factor is somewhere between very low to non existant. A speakers impedance isn't linear. It's a reactive load. So probably this amplifier can't sink current from the speaker. Anyway..

The amplifier OLG drops almost 14dB with a load connected. Probably because we have no drivers, and the vas sees the speaker impedance times output Hfe.

The square waves are all done without input filter at 2V out with 100nS rise/falltime . I think it does'nt look too bad.
The step responses are at 2V and 8V 20Khz with a 200KHz square wave on top. Rise/falltime is again 100nS.

I am aware that Hfe of the outputs might rise with increased heat. I will test that in reality later on, and implement temperature control if needed.
I am also aware that the UGLF is quite high, but it doesnt seem to cause any problems. Please correct me if I am wrong.
The cascode on the input fets will probably get dropped. It does'nt seem to do much difference in this design.

Here are some pictures, and offcause the .asc file for LTSpice.

Let me know what you think, if this is viable, or it should go directly into the trashbin.

I am also interested in other designs that work like this, if you know of any.

Merry Christmas

Hi,

just some ideas about discrete Buffers for Line-Level.
I was a bit surprised that I couldn´t find some of these Buffers here at DIYaudio, so I thought I´d give it a try.

Starting with ´A´ the well known and very simple CCS-loaded Source-follower. This can give already good distortion figures and a Buffer can´t be much simpler than that. If J1a and J1b are matched -matched Duals here- one can omit with output coupling caps if the input signal is free of DC.
Beeing a singleended circuit the maximum current into the load could only be once the bias current. This means that it can only drive highimpedance/lowcurrent loads well and heat losses in the JFETs are high.
With smallsignal high-gm JFETs also the supply voltages are usually restricted to less than +-15V.
´B´ is a cascoded variant of ´A´. Here J2a and J2b run much cooler, since the cascode JFETs J3 and J4 provide for low and nearly constant Drain-Source voltages. J3 and J4 may be high Idss low-gm types, which take over most of the heat losses. While the load drive capability is nearly the same as with circuit ´A´, the distortion figures are considerably lower. If J2a and J2b are closely matched, the output offset will remain low enough that no output cap is required, even with unmatched cascode JFETs.

Circuits ´C´ and ´D´ are an idea -I haven´t seen it here before, but very probabely it´s nothing new at all- to increase load drive capability.
It resembles characteristics of a Sziklay- or Compound pair and cascodes.
Circuit ´C´ could probabely named HCC, Hybrid-Cascode-Compound, circuit ´D´ could be called FCC, FET-Cascode-Compound.
Both only differ structurally by the useage of PNP resp. PMOS as output devices.
The voltage drop over the cascodes drain resistors are used to bias and modulate the output transistors.
The two circuits allow to drive much lower impedance loads than ´A´ and ´B´, due to the much increased bias currents (10x and more).
The extreme short and direct feedback loop of the Sziklay pair preserves the good THD-values of the cascoded JFET stage. Since the JFETs may run on smaller bias currents (more degenerated with larger source resistor values) and drain voltages, they run alot cooler. Temperature and temperature drift issues are lower. The Potis in the CCS-JFETs drain allows to tune the output offset, so that no coupling cap should be required. Tolerances of the PMOS might be checked though.
Headroom is lower than with the simpler circuits ´A´ and ´B´, especially with the PMOS output devices of ´D´. With +-15V supplies ´D´ is capable of 4Vrms which is more than sufficient for typical high-level applications.
´D´ shows slightly better THD than ´C´ with highimpedance loads, while ´C´is slightly better with lowimpedance loads and can drive up to 6Vrms.
Using the simmed devices (all in SMD) one could use the same layout for ´C´ and ´D´ for easy evaluation and comparison.
Does anybody recognize some hidden drawbacks apart from possible need of matching the PMOS?

jauu
Calvin

I have for some years been using the DIY edition of the Minidsp 2x4HD without DAC's, named Nanosharc. I have sent the I2S output to two Soekris 1021. Their solution has worked really well for me, the software is easy to work with, and it worked well with the two inputs.
After a firmware update, the unit sends no sound, neither from the Toslink or USB input. I am in contact with Minidsp, but they are slow, and although I still hope for a helpful feedback, I hate being dependent on them for my lovely sound system to work. What else can I do to keep the two Soekris DAC's? I am looking for a kind of DSP solution where I can send two I2S signals after crossover and other DSP processing.
Any advice will be helpful.

I have a PSB Alpha PS1 Powered Speaker System with a blown woofer. Need help where to buy parts. 3.5" Woofer. 8 ohm 40W. any help would be appreciated.

Looking at this 2 cabinets for Mark Audio CHN 110 I am in doubt:

They seem to have more or less the same volume, and what is the advantage over the DCR Dual chamber bass reflex cabinet over the normal bass reflex?


Updated: I found the Double Chamber Reflex (DCR) article on Electronics World by G.L. Augspurger / December 1961 and attach bellow too for who may be interested.

My best wishes for all the community for the new year hoping that during it, all our projects can be true and saturated of happiness. Merry Christmas for all folks here too.

Salu2 ara to2.

Hello Guys,

I own an old Realistic SP-150 speaker (2W @ 8 Ohms). It's the same model that was used in the Nasa Control Room for Apollo mission communications.
What I would like is:
- transform this passive speaker to an active speaker with a small mono amplifier and WITH a balanced XLR Input.

I tried to find some electronics boards, but I can't find a small board (or drawing) with a small amp, ideally 12V input or less and this famous balanced XLR input. I don't want an over powerful amplifier like 60W or more. Just the right one for this speaker.
Do you have any idea where or how I can find it ?
I can do PCB and soldering or buy a fully finished product.

Best regards,
Marc

I had been endlessly trying to get a scrapheap amp back working and sounding somewhat good, but just could not get her working. See the thread over here.




Anyway, in the end I just gave up and in an effort to salvage something, anything, I hit upon this schematic, courtesy of tubecad:



The thing is, this one sounds absolutely fantastic. Nothing special on any of the parts, all are stuff I had lying around, although I think my transformers are sowters. Anyway, after sorting a few issues with hum etc (thanks again trobbins), this amp is sounding just great. Its easily on a par with the F5s that I've built, and having compared with other amps I've heard, it stands up very well. Soundstage is wide and deep, treble is sparkly and clear with no harshness, bass is tight - although I have heard it in bigger quantities. It really is well worth a mention here as a nice amp to build, lowish to medium gain, and about 8W so good enough for horns.

Its simple enough to build with a low enough parts count. From the tubecad site:

EL84/6BQ5 Push-Pull Power Amplifier
Few tube amplifiers sound as sweet as two triode-connected EL84s in push-pull. These amazing little power tubes are quite efficient, requiring only 15Vpp to bring them to full output. Thus, with just a single input/phase-splitter tube, such as a 6N1P or 12AT7, we build a fine push-pull amplifier.The 6N1P is a fine little tube and about 1Vpk of input signal will bring this amplifier to full output (about 8W) and no feedback loop is employed. The input stage and split-load phase splitter define a CCDA and present an equal amount of B+ noise to the output tubes' grids, which will help reduce the noise at the output. (By the way, the 0.47µF coupling capacitors could be replaced with something smaller, say 0.1µF.) I would use old Dynaco ST35 (also SCA-35) output transformers (about 8k P-to-P), which are stellar performers.

Click to expand...

Fran

Hello,
I recently purchased new FR speakers from a small french manufacturer called E.M.S. .
They make multiple professional FR speakers that are supposed to be really really good...and as I heard the biggest one (lb12) playing the stars from the sky in a high end setup (https://www.closeracoustics.com/loudspeakers/vigo ) , I jumped in and ordered the same woofers.

Now i would like to test them in an existing diy design that comes close enough to suit their T/S parameters...
could anyone help me identifying what design could be best suited ? Joan, Victors, Vulcans, pencils???, preferably back loaded horn design but not mandatory...
Here are their T/S parameters, I have 2 sizes the lb8mk2 and LB12 mk2

http://www.emspeaker.com/fiche_LB12MKII.pdf

http://www.emspeaker.com/fiche_LB8MKII.pdf

Thank you for the help...
Yves

Just wondering if anyone has actually built a 6DJ8 preamp with moderate B+ of say 150V or so. It appears like it should work OK. Thinking input stage with plate to grid FB followed by an active tone control. Perhaps 60-70V on the plate with 3 or 4 mA plate current.

Hi,

I just realized my new Visaton WS 17 E - 8 basses paired with GRS 1TD1-8 Dome Tweeter and biniding post you can see complete work in photos. One is with the opening at the top still looking for the internal box insulation. Any Thoughts?

My personal exposure to ESL-63's is nearly zero, I heard them decades ago. But I love the whole annular ring concept to emulate a point source from a flat sheet.

My question is, do you ever hear it? Does this ever intrude into the listening, or generate any audible 'lobiness' as you move around?

Thanks.

The Hypnic Power Manager


Features

• Switch power on/off to SBC
• Provide power switch for SBC
• Provide power status with LED
• Remove battery maintenance (use supercapacitors)
• Provide enough energy to allow the SBC to power down gracefully
• Optionally, power on SBC when external power is turned on
• Optionally, power on SBC only where there's enough charge

The Hypnic Power Manager does all of this in a tiny footprint. It's designed to be used with any 5V external power supply of your own choice - a simple wall wort or even an AliExpress special will do, it's not fussy - as long as it's 5V.

When the power button is pressed, or after the external power supply is removed, the board uses supercapacitors to power the SBC - this power supply will last approximately 30s depending on power draw from the SBC. However, the Hypnic sends a "shutdown" signal to the SBC by pulling a pin low on the SBC. A script on the SBC detects the pin state change and shuts down the SBC. Once the graceful power down is complete, a script to pull a pin on the SBC high pulls a pin high on the Hypnic and it removes the power supply to the SBC.

It's powered by an ATTiny24/44/84 and the code is written in Arduino (as that's easier for most DIYers) / Python for the SBC elements - all code is open source, so you can modify and reflash the controller, although you will need an ICSP programmer. The schematic, PCB layout and code are all completely open source.

Why isn't this a Pi HAT?
Screw terminals for all connections to the SBC - this is an intentional choice to make it work with all SBCs - not all SBCs have the same layout as the Raspberry Pi - if this was "Raspberry Pi shaped" (i.e., a HAT) it will only really work with the Pi. Sure, you'll need to hook it up with a few wires, but now it'll work with any SBC and you don't have to mount it on top.

Why did you make this?
While building a new digital audio player based on a Raspberry Pi (a story for another day) I wanted to turn the Raspberry Pi into an "appliance". Like most Single Board Computers (SBCs), the Raspberry Pi by itself doesn't (really) feature a power button without abusing the GPIO. On top of that, you can't simply remove power from it in since it's very possible that you'll either suffer data loss or, worse, corruption. I needed a way to gracefully power down when power is removed. I couldn't find a solution to this off the shelf that wasn't a battery-based UPS. This doesn't work for my application since I'm not trying to keep the Pi running, I want to power it off!

To be clear, yes, I know you can short GPIO pins to power on the Pi, and you can use scripts to with GPIO pins to power it off again. I also know there are UI options - but they're not always practical. And none of these protect against power loss and brownouts, which is something else I need to do.

There are many "UPS" solutions, but they're intended to keep the device on for as long as possible and most don't have a nice way of powering it back on again and virtually none support a power button. On top, they all require batteries and battery maintenance, which is a pain. The answer, of course, is to build it yourself. Enter the Hypnic Power Manager.

Hypnic?
In case you're wondering about the name, a Hypnic Jerk is that sudden movement you get just before you go to sleep... I thought that was apt for a device designed to provide enough power to let the SBC "sleep" and power it down!






More Information / Documentation
falk/hypnic at main * gilphilbert/falk * GitHub

Code for the ATTiny
GitHub - gilphilbert/hypnic
This is ready to be opened in VSCode

OK, OK, I want one!
The Hypnic Power Manager is $20 including P+P to mainland USA. Shipping to elsewhere will add some shipping cost. Just PM me with your order!

I am working on a Pioneer SX-3900. I see where the KSC1845 is accepted as a sub for the 2SC1775A. I am out of the 1845s. I have 2SC2240BL and 2SC2705Y in my stash. It looks like they would work also.
What do you think?

I am looking for using the wm8805 for simple i2s to spdif converter board and have checked the wm8805 datasheet and some schematics from other implementations. In some diy implementations I found from the internet the TX0 is put directly to toslink output jack while in some other implementations there is a voltage divider implemented + 0.1uF cap before the spdif output. Is the voltage divider and cap really needed and what is the purpose of it?

For example this project uses 210 and 110 resistors and 0.1uF cap. https://www.dimdim.gr/diyaudio/spdif-receiver-with-the-wm8805

Mika

Dear all,
I write from Italy and I have a Soundstream TC306 and TC308.
TC308 is fully working but with Japan frequency. I would like to modify for europen radio frequency
TC306 is with european frequency but with problem on tape. mecanically is fully working, but when I paly the cassette I listen only radio audio.

I'm looking for service manual, but seems impossible to find it.
If anyone have service manual I appreciate a lot if can help me (I can pay it).
Best regards
Luca

Sinclair (Project 60) Z-30 amplifier and my DIY mods

It was in 1969 when Sinclair Project 60 kit appeared on the market in UK and it contained Z-30 amplifier modules, advertised as 25W and 50W peak. It also advertised to be “the world's lowest distortion high fidelity amplifier”



and the news and kit description had soon, only few months later, appeared in our local hi-fi magazine Hudba a Zvuk.



Those days I was building my first amplifiers (with Singleton input stage and awkward circuit topology) and I was excited by Sinclair topology! The differential input stage, CCS VAS load, it was something completely new in the DIY world. However, for us behind the iron curtain, an unobtainium. We had the only chance, to learn and to design and build the thing ourselves.
Several years passed and after I finished my university studies I was still an enthusiastic DIYer and I have returned to the idea to build Z-30. So I took an original schematics



made some small mods like modification to +/- DC power supply (to get rid off the output coupling capacitor) and also changed the transistors, as the originals were not available here. This was probably a good idea, as my power transistors were more robust. And this was the result, in 1980



I have chosen a modular concept, with a motherboard and modules that could have been changed to make different amp configurations. There was an RIAA phono module, linear preamp module, bass/treble equalizer module, two modified Z-30 modules and a power supply. All except for Z-30 were my designs. It took years to realize the project and this was the result in 1987



The amplifier was working well and had served me till 2001, the year when I returned to DIY hi-fi and realized to build something more advanced. The amp shown suffered from 2 major issues
the heatsinks were too small and continuous available power was thus reduced (similarly as in nowadays miniature TPA3255 amplifiers)
due to absence of Re resistors and poor idle current stabilization the idle current had to be kept very low, in order to prevent thermal runaway and destruction of power transistors. As a result, there was the crossover distortion. The same issues applied to original Sinclair modules.


Sinclair Z-30 rev2014 – my 45th anniversary project

In 2014, I got an idea to wipe dust from the Z-30 project and to make some modifications and make it a reliable amplifier with continuous maximum power capability, thermal stability and optimal bias of the output stage, to get rid off the crossover distortion.

This was running pretty well, with power specified at 50W/4ohm, thermal stabilization of idle current and appropriate heatsink.


Z-30 2019, last mod 50 years after

And this is my last (as for now 🙂 modification from 2019, 50 years after the original Z-30 was issued.

Schematics and PCB - this is the valid project schematics!



(Gerber files are attached at the bottom of this post in the z30_new.zip file, as well as the parts list in pdf)



Measurements

THD and THD+N vs. power at 1kHz/4ohm

We can see that the amp gives 50W/4ohm

THD+N vs. frequency - pretty flat


Distortion spectrum


New: 20kHz square response


So this is my story of the Sinclair Z-30 amplifier. Even after 55 years, its basic topology is able to give good results. We have not moved much, since 🙂. Have fun with DIY!

Literature

[1] Project 60 Sinclair, Manual
[2] Dale, R.: The Sinclair Story
[3] Self, D.: Audio Power Amplifier Design Handbook, 4th edition, Newnes 2008
[4] Project 60 firmy Sinclair, Hudba a Zvuk, 7/1971

Hello all!
My Fane-bass-reflex speakers are finished. Time for the next project 😵

As the title says, I managed to get 2 W4 2130 Si for a bargain and want to build some PC-speakers.
(https://www.tb-speaker.com/uploads/files/37a412234362bf9297d386299feba31a.pdf)

Currently I have 2 large 42L bass-reflex speakers with W8 1772s in them, but I want to sell them as they take up too much space on the desk.

Concerning desktop/bookshelf speakers, I checked out the "Baby Labs", and fell in love with a smaller, more compact transmission line. However the Baby Lab-models all feature different speakers than the ones I have.

Now I have 2 questions:

Should I just pick the Baby Lab-model that has the closest T/S-parameters and go with that?
(I already compared them and the closest matches I found were the Mark Audio Alpair 6.2 or CHN-70)
https://www.markaudio.com/online_shop/archive/alpair-6-2/#link_additional_information_tab https://www.markaudio.com/online_shop/ch/chn-70-paper-pair/#link_additional_information_tab

Or is there any way a newbie like my can model a MLTL for W4's? I have only worked with WinISD so far.
I have studied the Baby-Lab plans a little and I noticed: there are always three internal walls. And they are always spaced a half length from the previous one. So if the first length is 12cm, the other one is 6 and the last one is 3. Also the vent is always equal to the last walls length, so 3cm.
But that's only what

Ideally speaking maybe someone more knowledgeable than me has the time to do a quick calculation or so, but I hesitate to ask :-D

as above.

I was looking at crossover and notice the wirewounds 15W that's being used.

I'm wondering if

1. the current going through the resistor is constant (thus the resistor temp is constant)
2. OR perhaps the resistor only warms up in certain situations (playing loud music or maybe the resistor only warms up if certain frequencies are played)

Thanks!