This is from the biasing board for a Willsenton R8 amplifier. Ostensibly it's a wirewound rheostat.

First, I'm trying to identify the company.

Second, looking for suitable replacement (preventive, not needing replacement at this time although a few folks HAVE had issues with them. Willsenton just sends them new boards).

Did I search the web? Yep. Pages upon pages of logos.

Did I contact the company, Willsenton? Not yet. Too easy.

Thanks in advance.

Bought a pair of these a while back when I was planning an EL34 Baby Huey amp...happy with my stash of amps and now up for sale...

4k / 8 ohm

How's $100 + ship for the pair?

CONUS Please.... they are HEAVY

Witness the new Keithley/Tektronix DMM6500.
6.5 digits.
min range DC 100nV, 10pA; AC 100nV, 100pA
R: down to 1uOhms, C down to 0.1pF.
Etc, etc.

I remember that such high performance, scientific instruments cost north of $ 10k.
This one is ... drum roll ... $ 1600.
I know, it's serious money, but still. No bench should be without it.

Jan

Customer said his 2505 took a fall. The pots are smashed in. I was able to repair one of them, but the other one has a crash in the diecast metal thread assembly which separated from the part of the diecast that attaches to front of pot.

McIntosh p/n 134-207. 250K. Shaft is 2-5/8" long.

Anyone got one? Or the diecast part so I can fix this one?

Up for sale a pair of ellipticor tweeters and a pair of 12m revelator midranges

Both are used for a very short period of time about one month.


Price is 800 euros for the ellipticors and 400 euros for the revelators
Shipping and pp fees are not included

Which is the fastest NPN/PNP pair power transistor for output stage ?

Selling a lightly used xing u30 usb i2s interface, $50 shipped within US plus paypal fee.

Here is the link from aliexpress,
https://www.aliexpress.us/item/3256802489957909.html

I would like to add a POM top platter to my TT, 25 mm thick and machined to fit the existing aluminium base platter.
I cannot machine this, would anyone who has the capability like to help or might point me in the right direction please?
I am in Hampshire UK

I got a secondhand Numark CD Mix-1, but the audio on channel B is much lower than channel A. I've taken it to a local audio repair shop, but the service manual is not available to help them repair it.

I saw this thread but it's closed:
https://www.diyaudio.com/community/threads/numark-cdmix1-service-manual.302588/

Does anybody here have the Numark CD Mix-1 service manual?

I have a Willem Programmer and works great for my EPROMs (29F04), but having issues getting a HEX file onto a PIC16F72 / PIC16C72...anyone out there able to burn me a chip if I supply the HEX?

Let me know.

Thanks

I don't suppose anyone has 2x keratherm pads cut for the to-247 package (like on the diyaudio store) that I could buy from them? Really in the UK, can't see it being worthwhile from anywhere else.

Just made an oversight when I bought a pack of 10, when I need 12...

Rapid does have small sheets that I can buy, but it is £25 delivered and they are on back order.

Hi All
I have an R8 with what I think is a bias board issue
I have been in touch with the distributor , Audiophile Amplifier store and this was their reply to me

"We are sorry for the trouble!
Maybe we still need your help to do some tests: 1. Measure whether the light point is connected with the ground box (refer to Figure 1) 2. Turn on the power and measure whether the red point (V3) in the picture is the white line contact point to see if the voltage is between - 40 and - 45 negative (refer to Figure 1) 3. Turn on the power and measure whether the red mark point (V4) in the picture is the red line contact point to see if the voltage is between - 40 and - 45 negative(refer to Figure 2) Thank you for your understanding and trust! Take care of yourself and stay healthy. Sincerely, Audiophile Amplifier Store"



Thank you for your reply do you think it is wise for me to be testing inside a live tube amplifier? regards


"Yes, There is a fuse in the amplifier. If you operate normally, there is no problem."

With the tubes in?

"Yes"

That was the end of our conversation
Is this not a bit strange or am I being over sensitive?

Hi, has anyone made this? I would be curious! 😉

Has anyone had a positive experience with upgrading crossovers for the 12” Golds from the original crossovers and level controls to a more robust layout with higher quality inductors and caps? I’ve been looking at the examples from Mainly Tannoy as an upgrade possibility. Any suggestions or experiences you all might share? Thank you for this amazing community. I’m driving my beautiful Tannoy’s with Pass Aleph P and a pair of Super built DIY Aleph 2 Monoblocks. The sound is just amazing with such a natural balance and deep soundstage. Bass is augmented with a REL T9i, plenty of bass for my dedicated 20’x22’x9’ room.

Hi guys😀
this is my lately DIY sweets😉 it is a very simple design,purpose for general use.

sch:

Below is an LTSpice model of a prospective PP amp with 1625 using UNSET topology. Of course the real amp will have adjustable bias and grid and screen resistors etc but first I just wanted to rough this out. Input will be from a balanced source. This model is biased for the outputs to remain in class A and develops about 20W at clipping. Spice says it seems to want 10-11K primary impedance transformers at this plate voltage of around 400V. Any major flaws? Other things to consider?

A pair of unused 0.47uf/630V Vitamin Q Oil Paper Caps by Tone Factory, Toichi of Japan.
60 USD, shipped to you with tracking.
PayPal Friends/Family only please.

Hi all, long shot I think, but before I try bd-ent (I see they have some pairs but I'm skeptical on what grade I'll end up with) I wanted to see if anyone had a pair of these lying around? I thrifted an audiolab 8000x7 with 7 working pairs of P grade inside so only need 1 more pair to finish my wolverine.

So 1 pair, preferably P grade or higher, Y would also be okay if HFE was known ~80 or higher. Cheers.

Hi everyone!

Because LM3886 is nowhere to find (out of stock), it will be nice to have a discrete substitute design!

I have created simulation of an amp in LTSpice simulator. I have tried to stay as close as possible to the internal LM3886 schematics.
THD is 0.0002% for 2V input at 1kHz.
OLG is >70dB at 20kHz.

• Mainly for the input stage we have long tail pair arrangement loaded with current mirror that employs a helper transistor. Constant current source is supplying 2mA and created with two transistors.
• For voltage amplification section LM3886 is using two transistor emitter follower configuration. There is some kind of buffering happening, but I lack expertise to determine what it is. Instead it was replaced with Hawksford enhanced cascode.
• Miller compensation was replaced with two pole compensation. On the board I plan to have ability to switch between two. Also, thinking about adding option to do transitional Miller compensation. So in total three different compensations to select using jumpers on the board.
• For output stage it is a simple 2EF (two transistors emitter follower) with driver and output transistors.

Attached are schematics and files.

I am also planning on making SMD / THT board that will have similar outputs as LM3886, namely inverted input, non-inverted input, etc..

As far as protections, I am planning on using four diodes: from each rail to ground, and from each rail to output of an amp.
Any other suggestions for the protection will be helpful.

Not sure about phase margin stuff yet....

Let me know if I missed anything, appreciate any input.

I'm a bit frustrated. I'm trying to find a good sounding horn for my coax B&C DCX50 that will allow me to cross 500hz or lower 2nd order, but I can't find anything that will get even close to my standards in terms of low coloration. Yeah, sure you can EQ anything to death, but it still sounds like crap if what you're listening to excites any resonances. Please don't suggest DSP. This has to be an analog solution, mainly becuase i listen to alot of vinyl. I know it's likely not the drivers fault, becusse the driver actually sounds great without a horn and the impedance plot looks very clean. Not saying that's a tell all sort of analysis, but from my experiences it usually shows alot of bad character traits in a driver having lots of impedance peaks ie. resonances. Ive already tried the common garden variety horns which are usually very narrow dispersion pattern types in this 2" larger format lower cutoff range.

I sometimes like to listen LOUD and don't want to hear any of those nasty spots or internal reflections most horns have. That's what turns me off about most horn loaded designs. I've heard some good ones and many many more bad ones that make your toe nails curl up. If the designer got it right, its pure heaven, but most of the time it sounds awful, even when people think it isnt. I'd spend the money on something if I knew it was available without fear of shipping damage from oversees and it didn't look like a piece of ugly art deco. I'd be happy with a Juichi A290 clone of sorts, however they don't exist for purchase here in the US. All of the typical fiberglass and pro sound horns just don't cut it for me. I've tried alot of them too. This may sound stupid, but I'm trying to build something while I'm still capable. Once my garbage health takes me to the point of being a cripple, all I'll have left is listening to music if it doesn't take me down completely before that.

Any real suggestions?

I have recently acquired a Victor TT 81, and mounted it in an experimental plinth with my diy radial TA.
I had good fun making it work with help from some members of the forum after transport damage.
It is promising.
The platter is aluminium and the mat is old and tired, needs replacing, but by their nature they are all going to be old and brittle, what is the best diy or new oem solution please? The platter rings on its own and is controlled by the mat i believe. The matt is 5mm thick.
Anyone else with experience of this TT?
M

I have Mundorf SGO 4.7uf capacitors I want to sell. Used item, has a few scratches on the case due to accidentally touching the soldering tip. Desired price 200$
I conducted measurements with a Keysight U1732C LCR meter at 1Khz of 4,748uf and 4,723uf
Pay via paypal friends.
I live in Ho Chi Minh City, Vietnam
Thank you!

Hi all - I bought an old Luxman/Luxkit A3600 from Japan (100V) last year and have been having a ball trying to understand how it works so I can make sure the circuit is operating as it should and the amp performs at its best. The original tubes employed by the circuit were four Luxman 8045G power triodes driven by a pair of Luxman 6240G triodes and a 6AQ8 input tube. The circuit has previously had some adjustments to take 6550s/KT88 power tubes and 6CG7/6FQ7 driver tubes. I have since replaced the 20 year old KT88s for a quad of KT120s.

As it was built by a home hobbyist I've been checking over the components to see how they match the schematic (see attached). I've replaced some of the caps (being 50 years old) and bias pots with Bourns closed pots, which were a bit dirty and dicky. The amp produces music wonderfully well and I've very fond of it!

However, I've been reading about heater circuit design and note that this Luxman design has two separate 6.3VAC secondaries for each pair of output tubes (see pic below), the pair being wired in series. Each of the secondaries is rated for up to 5.5A and each KT120 heater draws just below 2A so there is about 1.5A headroom. However, I see there is no centre tap and no virtual ground using two 100ohm resistors, which I read is the done thing.

Do you think I should add them?

Note that the D306 NPN (1S1850) makes an 8V supply that leads to C310 2200uf (10V) capacitor and R308 100Kohm resistor and then on to a pin in a preamp socket (Luxman A3300 preamplifier), which isn't in use.

Wanted - Accuphase P-360 Schematic/Service manual.
Please let me know if you have one. I really need a copy

Hi all,

I'm building a streamer+DAC and just got the enclosure and the 7" touch screen. I need to cut a rectangular hole in the aluminum front panel which is 8mm thick. The screen will take up majority of the front panel's surface. I don't have much tools except a drill so my options are limited. I could drill a few holes at the start and use a hand saw with subsequent filing, but I'm afraid I will just ruin the beautiful aluminum panel. I'm in the UK and I would rather have it laser cut for a reasonable compensation. Could anyone recommend what kind of establishments I can reach out to? I have searched this forum and saw people recommending a nibbling tool, but I'm afraid the front panel is a bit too thick for this.

I just learned about Astrud's death at age 83 on June 5th in Philadelphia from a nice article in the September issue of Stereophile magazine penned by Rogier Van Bakel. "Her first professional recording became a career defining global hit, changed the culture, and helped make bossa nova a worldwide phenomenon." The article also tells of how Stan Getz (that rotten skunk) made sure she never received any royalty money from the album "Getz/Gilbereto". Her cause of death wasn't disclosed, but the bolavip website claims she was diagnosed with lung cancer since 2021.

I made a board for a project and ordered a bunch of them.

It takes 6.3V from the heater windings and makes 12V for controlling a relay etc using a Delon doubler and a 12V regulator such as MC29300 or LM7812. I use it with a dual winding 6.3V transformer using one winding for DC control, and the other for the 6.3V the biasing board requires.


If anyone wants any I'll offer them for 2$ each plus mail.

Cheers.
Koda

I have just finished recapping a dual showman reverb.
Every electrolytic replaced. Amp sounds wonderful, but I think there should be more reverb. There is fair amount, but I am not in surf territory.
Fresh tubes, and rca Jacks cleaned, tank inductors fastened.
Thought the reverb would go "way out", am i wrong?

Kind regards

Hello

im curious if anyone tried different sbc`s and compared them sound quality wise to eachother (and specially the raspberry pi) in a streamer setup?

specially interested in SBC`s that are gpio combatible with the raspberry pi (so hats can be used)

I have read so many threads, reviews, etc....my head is spinning. I have also tried to get the schematics to the circuit to no avail and tried to draw it out but get a headache doing so.

I believe only need to upgrade the high pass, set at 80Hz, as the low pass will be fine enough with the stock JRC4580D opamps. The plan is to upgrade the caps for the high pass and power supply as needed. DIP soldered in opamps, I could solder in sockets if need to test more than one opamp model for the upgrade.

Some state the 4580 is fine for this application but I find that hard to accept even though feeding to a tube amp(this amp has a very high bandwidth and a bit less of that smooth tube sound, more like a hybrid tube/transistor sound)

I prefer the smoother sounding opamps though I love the sound of the amp and speakers I could live with toning it down a bit more but not too much.
I was recommended to try the OPA2209 as an easy option but that it might not make enough difference to bother. I have read about most all the higher end opamps and many seem just to difficult to use not knowing the circuit design.

I just want to do something worthwhile, cost effective(if only two opamps and some caps cost is not an issue of course) and I just like to change at least something like I did on the speaker upgrades and now have to build new bass horns to fit, building the subs into the back wall of the RV, tube amp upgrades, DIY cables, etc....



PS is +/-15vdc as measured.
4580 on far right is part of the highpass, believe the one to its left is as well but kept getting stuck trying to nail it down.
Far left and the one to its right seem to only be tied to the low pass section.
Switch by the RCA connectors is the subsonic filter, middle is the bass boost, far left is the 12 volt trigger selector, on/off/auto

There is a much larger board in the front of the unit with many 4580s on it and controls for the EQ, etc...

Pretty sure just the two right 4580s have anything to do with the high pass filter.

System, rather low end compared to some but more than enough for our enjoyment. in our full time RV.
Mostly stream through a PC, Laptop, TV, QoBuz, no MQA and a modest CD, DVD and BD library through a good Panasonic BD player.
I am going to investigate steamers to see if really that important or not.

For now, Topping e30 DAC using Li battery, tested various power adapters, USB, like the battery the best. I am researching a bit higher end DACs, like AKG chips.
Baby Sophia tube amp with all pertinent upgrades and best tubes I could find, cheap so bought several spare sets.
SA1000 sub amp, 1kw rated AB, been using it a long time, it works great and has a single band variable EQ, Q and phase as well as variable low pass xover, fixed high pass at 80hz which might be just fine since the main speakers only go to 70hz and drop off from there.
Edgarhorn Slimline speakers(Dr Bruce was a great guy, glad I got to know him) huge oil filled caps, foil inductors, better resistors, Fostex super tweeter.
Dual Image Dynamics ID15 subs, sealed enclosures(another great guy I got to know, Eric Stevens)

I can take measurements though no longer have test gear other than a decent DMM and a good solder station as well as a higher end solder vacuum tool.

Any help will be greatly appreciated🙂
Thanks,
Rick

Hello friends, again bothering you, I have a Hifonics BXE2500.1 amplifier and the problem it presents is that the power supply fets heat up and the supply voltage drops from 12v to 9v with a high current consumption, I have limited the supply to 2 amps and consumes them, if I increase to 5 amps, it consumes them. The strange thing is that the signals for the power supply and amplification are fine and there is audio at the outputs, I do not understand why the power supply fets heat up and the excessive current consumption, in advance greetings

Many moons ago I bought a pair of small Peerless drivers on ebay. I'm getting around to thinking I might play with them.
I'd hoped to find some information on them though - but I've come up short.

Does anyone have any information?
They are about 116mm across the (metal) chassis, have large bucking magnets in robust cups on the back.
Marked 'Made in Denmark', 'Peerless', '831979' and '8Ohm'.

I do have a DATS2 but to date I have not attempted to use it in anger, and I'm wondering whether I could use a 1p or 5p coin as added mass somehow, or I'd be better trying to make an enclosure.

I have this audio switch IC - 4 analog inputs to 1 analog output, controllable over I2C.

What's weird is on the analog inputs the spec PDF shows a normal load resistor (100K), followed by a 10uF capacitor. Normally for blocking I see the capacitor first, followed by the resistor.

Is this a mistake, or will it work like this too? The outputs from the IC have it the other way, OUTPUT -> CAPACITOR -> RESISTOR TO GROUND, which is how I'm used to seeing it. I'm just curious if it serves some other purpose the way they've done it on the inputs, or if it might be a mistake?

Thanks.

Greetings all,

Does anyone know where I might find out how to test this tube with an Eico 666 tube tester? I have the 1978 chart and no 6a5g listed.

Thanks in advance

🤣

I asked ChatGPT to...
Write a 500 to 600 word script for a promotional video for a new type of encabulator, the "Audio Encabulator", meant to be used with high-end extremely expensive audio systems. Use a lot of non-sensical technical jargon in describing the "Audio Encabulator". Use terms that imply magical forces at work that will improve the perceived quality of the audio.


Narrator: "Are you tired of your audio system falling short of its full potential? Are you ready to take your listening experience to the next level? Look no further - the Audio Encabulator from [Company Name] is here to revolutionize the way you experience sound.
"The Audio Encabulator is a state-of-the-art audio enhancement device designed specifically for high-end audio systems. Utilizing advanced sonic transmodulation technology, the Audio Encabulator imbues your audio signal with a level of clarity and precision never before achieved.
"But what exactly is sonic transmodulation, you might ask? Simply put, it's the process of modulating the waveform of an audio signal to enhance its clarity and definition. Our proprietary psychoacoustic harmonizers work in tandem with the transducer array to precisely calibrate and modulate the audio waveform, resulting in a level of sonic immersion that will transport you to another realm.
"But the Audio Encabulator doesn't stop there. We've also included advanced vortex-based phase shifters, which harness the power of quantum entanglement to elevate your audio experience even further. These phase shifters work by manipulating the phase relationship between different frequencies in the audio signal, resulting in a more cohesive and immersive listening experience.
"But don't just take our word for it - try the Audio Encabulator for yourself and experience the magic firsthand. Our team of audio engineers and acoustic experts have spent years perfecting this revolutionary device, and we're confident that it will take your audio system to new heights.
"So why wait? Upgrade your audio system with the Audio Encabulator today and join the ranks of the audio elite. Your ears (and wallet) won't regret it."

20-25 years ago Japanese manufacturers went on some bizarre, space-age trip. They started manufacturing weird-looking, plastic endowed speakers modelled on the Star Ship Enterprise. In 2023, they're just plain hideous!

Bought these for £8.


And I literally pulled a pair of Sony midi hi-fi speakers from a dumpster. The bass drivers were shot but tweeters functioned ok.

I wanted to make something that I could set up outside for barbeques etc. Something that cost nothing. Something that I wouldn't cry about if it got wet in a shower or if burger sauce got dripped on it.


Voila!



It's far from finished but I'm shocked at how good this sounds outside. I'm having a small problem with the sub grille (rattles) but that will be cured when I can get hold of router. I also suspect the Bluetooth TPA3116D2 will object to 3ohms on the mono channel at some point.

My total cost including Bluetooth amp and laptop brick will be less than £30.

Thoughts?

Just a really quick one.
Hopefully!

I have read that there is a quick mod for the C-Note speaker's crossover that apparently involves adding a 0.22 uF poly cap.
What I can't find is where to add the cap in the xover and what it is there to achieve.
Can anybody point me where this info might be listed?

Thanks,
Rob

I have zero knowledge of class a/b amps.
This amp was drawing current.

I found 2 dead transistors in the output section. After removing them the amp will no longer power up at all.

I put replacements in and still nothing. Then I took all of them out. Still nothing. I don't get it.

Pin 13 is only at .6v otherwise all other voltages seem correct. I don't understand where the 12v is supposed to be coming from because when I follow the traces the go to the output section. I have 12v on pin 15 tho.

Assuming I'm aesthetically set on a 2-way smallish tower with one or two 5-7" woofers, is there and reason NOT to build a transmission-line style speaker? What are the potential drawbacks of MLTLs? Something like this from Troels Graveson.

Cabinet complexity (within reason) is not an issue.

Hey Folks...

Im trying to design a room that people can walk into that resonates at 111hz specifically.

The wavelength of 111Hz is 3.092m and I'm ok with standing waves (if that equates to point of maximum resonance) as long as about 6 people can experience the standing wave points at once. The people could be laying on beds or standing at specific points in the room.

Do you think I should build a hemisphere or a cuboid? What radius/length should it be? and where would you place the speakers/instruments to create the maximum effect... in the walls, and if so where in the walls, or in the centre of the room?

Many thanks in advance.

I'm selling a pair of vintage Magnepan SMGa, restored and in excellent conditions. 800€ including shipping anywhere in Europe, or make a proposa

Decided to sell these unfortunately, I have the usual 'magpie' thing where I feel the need to jump onboard all these great projects. Alas I have many preamps and only so many hours in the day. Hopefully this can go to a good home and find it's designed purpose.
Asking £100 plus postage.
Includes the NE5532 opamps and a set of 6x 5k linear pots.
Populated with all good gear. The opamp PSU bypass caps are Panasonic. Gold plated Harwin IC sockets. Mainly all from Mouser bar the pots. See the paralleled R on the underside. Seems I didn't have that value on hand at that time!
Cheers
James

I have a couple Project brand Turntable platters for sale. good for your own DIY projects.
the first one is an acrylic platter. I have no idea what model it fits for sure. RPM3 likely. but, use it for your own experiments. $35 shipped

the metal one i am pretty sure came from an X8 but it is missing the magnet from the bottom of it. again use it for your own experiments $50 shipped

Also have a technics platter. SL1500 i think??? $30 shipped

I'm putting together a little workshop/seminar for BAF. LTspice can be a little intimidating for beginners, and perhaps a little clunky if you're already using a more user-friendly spice. However, it is very powerful, free, and used by many, many engineers and hobbyists everywhere. So, if you can get yourself over the initial learning bump, you'll discover a whole world of interesting things to do with this very useful tool.

This will cover enough LTspice to get you started. It's basically a bunch of material from my upcoming reference book of the same name. You'll build schematics based on some of your favorite Pass DIY designs, simulate them, compare simulated measurements to the real world, and more. If there's something specific you'd like to see, this is a good place to ask and I'll do my best to work it in if there's time and it's suitable for our audience.

Bring your laptop with LTspice installed for the best experience. I'll bring training materials for you to load up and take home with you. 🙂

Looking forward to hearing from you. 🙂

I was thinking of using a small trim pot in the feedback loop of an op-amp (in series with another resistor, i.e. 5k trim pot with a 50k resistor in series, both compromising the total feedback resistance) pre-amp to make some fine adjustments to the gain. Will this have any detrimental affect on amplifier noise (I was wondering if the noise in a trim pot might be worse than the noise in a typical resistor). Thanks.

I am a newbie to audiophile stuff and have received my Tu-8600S kit today so will document here the journey of assembling it. Will no doubt have lots of questions, and looking at you all for help.

After an initial UPS hiccup yesterday the package was delivered this morning and it is very well packed -- triple packed actually. I read the manual and now am sorting the parts.

noticed that my temps were going over 50c.
How hot is too hot for a Transformer. This is a locally made 12 to 15 amp transformer.
I am using a safety bulb 100 watt. You guys call it a safety lamp.
Can this impact the temps ?. It hardly glows.
What are the limits for heat sink temp and transformer temps. I have probes monitoring both now. I am monitoring the temps of the EI core metal plates.
This was the end of a long 8 hour shift with the music playing most of the time.
Is it the lamp causing it. Or the fact that its a poorly made local transformer. Because there is no way I was pushing it hard. Only the TDA7294 stereo amp was hooked up.
Heating is the same with the P3A amps also.

I posted on Reddit but also posting here for this audience:



I’ve been having fun trying out different fullrange drivers in a janky prototype OB setup.
Drivers & initial subjective impressions:

SB Acoustics SB65WBAC25-4 2.5" Full Range - Piece of junk, sounds tinny and distorted.

SB Acoustics SB20FRPC30-8 8" Paper Full Range - Biggest sound and most efficient of the bunch, but the least refined and very harsh/fatiguing in the treble. I don’t think I could live with it.

Markaudio Alpair-7MS Full Range - Best treble of the bunch with wide dispersion. Works great as a tweeter. My new favorite tweeter - better than Bliesma t34-a I think and significantly cheaper. Does not work fullrange at my preferred listening levels (moderate to somewhat loud). Sounds thin & distorted in the bass/mids.

Markaudio Alpair-11MS Full Range - OK all around. Alpair-7ms has better treble. Maop10.2 has better mids. Complex passages sound a little muddy.

Markaudio Maop 10.2 Full Range - Best mids & overall clarity. Vocals are especially great. Treble is lacking. Kinda mellow/bland sounding.

Misco Venturo 21” driver w/ 10mH inductor (supplementing bass) - extremely efficient with high EBP, which is needed for OB bass. I slightly prefer the Peerless 18” FSL-1830R06-08 for sound quality, but this wins for efficiency, allowing the fullrange units to be used unattenuated.

I like my long-standing favorites the Eton Arcosia 4” and 7” more than any of these SB and Markaudio drivers, BUT they are much more expensive, aren’t really fullrange, and are hard to find these days. The Arcosia drivers have better detail & clarity, especially during complex/layered musical passages, and are more euphonic overall.

My best results so far has been running 4 drivers in an WMTF wiring with the Misco 21”(sub bass <60hz 1o), Alpair11ms (bass/mid < 600hz 1o), Alpair7ms (treble > 10khz 1o), Maop10.2 (fullrange). It sounds pretty freaking amazing actually. Much better than any single driver or FAST arrangement.

None of the drivers have been broken in.

For Sale: I have some tubes and (2) Tubelab SSE PCB’s

Probably best for someone starting out and wants to roll tubes or plays guitar too.

(8) Shuguang “Coke Bottle” 6L6GC tube. I used two of them in the Tubelab SSE for a couple hours. I have no way of testing them. They are all clear. One tube is different style than the rest.

(2) Matched pair of JJ 6CA7. Never used.

(2) Matched pair of JJ 6L6GC. Never used

(2) Tubelabe SSE PCB’s. NOS. Never used.

The Shuquang site says the coke bottle style has been discontinued.

I would like to sell the kit as a whole. $325 shipped in USA. PayPal only. Thanks

I want to find the drawings of the case and crossovers! I will be grateful for the help.
Or a similar good two -lane system. 😳

Beginner here... I'm trying to design a small subwoofer box for a 4" Dayton Audio TCP115-8 using WinISD. I added the speaker in the database and created different projects using this speaker, but the port length is absurdly long (0.6 meters, or 1.3 meters for two vents). What am I doing wrong?

Thank you for your time and patience.

The BULLET Amplifier.

This is the power supply.
Each channel output is biased with 900mA.
This is enough to give a bit more than 10 Watt Class A into 8 Ohm.
The transformer is 2x24VAC with one winding each for the channels.
The voltage of supply is like 32.1VDC.

Those of you with very top quality custom crossovers and cabling for your planar speakers, what kind of leaps have you noticed versus what they were stock? Let's say a Magnepan crossover of today.
I would suspect planars to respond very precisely to improvements in the signal chain. They are not perhaps sensitive but they provide sensitive detail of the preceding chain of electronics.

Belt-driven turntables make up a very large proportion of the vinyl turntable range. Because the micro-elasticity of the belt itself can filter out most of the vibrations of the drive motor and the torque output that is not absolutely continuous, the sound of the belt machine is relatively analogous.
However, when you debug the speed of the belt turntable, you will find that the adjusted speed of the turntable occasionally changes slightly. For example, the originally debugged 33.33rpm changed to 33.42rpm after a few months. I think the reasons may be as follows.
1. Changes in room temperature will affect the softness and hardness of the belt. When the room temperature changes from low to high, the belt will soften slightly and the rotation speed will slow down slightly. On the contrary, the rotation speed will become faster. (For example, during the few months from winter to summer, the change in room temperature may exceed 20 degrees. According to observations, when the motor speed remains unchanged, the change in speed caused by room temperature is about 0.01-0.1rpm.) In addition, the belt Aging will also cause the belt to become harder and the rotation speed to become faster.
2. The tightness of the belt will affect the speed of rotation. Some record players have external motors, and such motors can adjust the tightness of the belt by adjusting the distance between the motor and the record player. When the motor speed remains unchanged, generally the tighter the belt is pulled, the slower the turntable's speed will be, and conversely, the speed will become faster. We can use this simple rule to fine-tune the speed. However, there is an appropriate range for adjusting the belt tension. If it is too tight, the friction between the motor shaft and the turntable shaft will increase significantly, affecting the stability of the rotation. If it is too loose, it will slip and affect the rotation accuracy.
3. The potentiometer for adjusting the speed was accidentally touched. The motor of some turntables can fine-tune the rotation speed. If the knob is accidentally touched, it will definitely cause the rotation speed of the motor to change, thus affecting the rotation speed of the turntable.
4. The speed control schemes of a small number of motors do not include phase locking or dynamic speed monitoring and other similar correction mechanisms. When the mains voltage changes greatly, the speed of such motors will change significantly, sometimes even exceeding 0.2-0.3 revolutions per revolution. minute. If this is ultimately determined to be the case, it may require frequent adjustments during use, or simply upgrade to a new motor.
The above are the common reasons that affect the rotation speed of belt vinyl turntables. I personally will occasionally measure the rotation speed of the turntable. If the deviation is large, such as exceeding 0.05rpm, I will make adjustments. If new reasons are discovered in the future, I will continue to add them.

In excellent condition and perfect working order.

No longer required as I’ve now sold my 220v Pathos amplifier.

240v input.
3 amp .

£100 plus shipping.

Hey Guys,

I'm looking for the gear wheels for the Nakamichi CA-7 volume motor, (Think its the same for most CA pre's) due to its age, the parts as been broken off. please find the attached part numbers.

i need the parts:

08 (must) - 0J05232B
13 (if available)
17 (if available)

does anyone know where i can find such ? or any mods ? 🙂

TIA

I have an Alpine MRV-t301 that I purchased with a fault - the seller described it as ‘no sound, it just stopped working’. Powering it up with music input and speakers, the amp plays music but kicks in and out steadily a second or two on and then off absolutely rhythmically.

Opening it up, I notice that there’s a large filter capacitor near the small transformer by the 12v input that is way too hot to touch within 30 seconds of turning the amp on. Desoldering it from the board it measures correctly using the Capacitor test on my DM. It’s 3300uF 16v. I’ve also checked all the diodes around it and all seem to be good.

None of the transistors on the heat sinks have shorted and there is no visible damage anywhere on the board. I don‘t have a scope and I’m very new to this but I have read an awful lot on the internet and watched a tonne of videos. I have managed to download a schematic but the resolution is so bad I can’t read many of the details.

Could someone which more knowledge than me perhaps give me some hints as to where to look. Also perhaps answer the following if you can from what I’ve provided so far:

1. Could the hot capacitor be the root cause/problem/fault even though it reads correctly on the DM when out of circuit?
2. Does anyone have a service manual for the MRV-T301?
3. Is absolutely steady cutting in/out of the music indicative of a common fault?

Probably worth saying that it looks like this amp has never had the cover off and not been worked on before. The inside is clean as a whistle.

If it seems I haven’t done enough homework, let me know also.

Thanks very much

Stephan

I'm looking to buy an a/d/s/ DA44 to fulfill my system, yes, it's car audio component but I used to use it in home and I like it very much. It's relatively rare though. I discovered that this DAC was designed by Ed Meitner of EMM Labs. Moreover, I also found that the home-used version of the DA44 is Museatex IDAT44 which was designed by Meitner as well. However, I have limited budget. So, I'd like to ask here if there's a cloning kit of the Meitner's designs available. Has anyone ever found the kits? Or if anyone would like to sell your a/d/s/ DAC, you can PM me.

I just picked up a non-functional, home built, 6L6GC push-pull amp for small money because I wanted the output transformers and telefunken 12AX7s. I repaired it and thought I’d gave it a quick listen first before I part it out. I’ve attached a shot of my wiring diagram. My concern is about the way the pentodes screen grids are wired. I assume the builder wanted to build a triode connected PP amp. In my experience the the screen grid pin is wired directly to the plate pin or alternatively connected with a 100R resistor. In this build the screen grid is connected to B+ without a screen resistor. In other words it’s connected to the same node as center tap of the primary side of the O/T. What am I looking at here?

I recently bought a DENON DRA-550 (from 1986) and need to buy speakers for it. What kind of speakers would be compatible with this model? Thanks.

tl;dr: I have a small form factor PC, and the biggest power supply it will accept only puts out 500W, while my video card needs 600W.

I thought to myself: What if I upgraded the transformer and uprated the filter capacitors? Could I get more out of the supply? Or would it become an endless series of upgrading each component to a higher rated value?

On the SSE website George said the value for C1 was not critical and spec'd anything between 22uF and 47uf (47uF being the upper limit for the 5AR4 rectifier). After he added some components to "make life easier" for the rectifier, he mentioned doing some experimenting to see if a higher value like 50uF was acceptable.

I can't find a subsequent thread or message that confirms whether 50uF/500V is safe to use or not with the 5AR4. Anyone?

At the other end of the spectrum, what would be the effect (if any) of using 22uF/500V?

I have a 650W 24VDC switching supply, so plenty of current on tap.
I would like to build a small stereo class d (or integrated) amplifier with it.

I'd like 100W+ at 1% HD and 4 ohm stability. Anybody recommend a module that will work well?
What I seem to running into is either not enough voltage in the supply for the power I want, or not enough power from what I have available in the supply.

Thanks for any recommended modules...
Wolf

The amp is to find here:
??????????????A????? - ?? - Yahoo!???

By operating both at this knob and the associated remote control there is not to observe any change of the input - only "TUNER" remains in operation.
How I can check the correct operation of the controller NEC µPD75004CU-199 ?
Is there a custom made (mask) programming applied?

The encoder looks not like that one from the first picture, but than the second picture from follow links:
http://www.mikrocontroller.net/attachment/38788/Encoder.jpg
??????????????A????? - ?? - Yahoo!???
Type No is follow: 9905400-332a (controlling by change of capacity ?)

What kind of encoder is this?

More URLs:
KENWOOD A-1001 ?? : ????????????
http://i01.i.aliimg.com/wsphoto/v0/1132010687/D75004cu-082-.jpg

Just found this curiosity in a bric-à-brac shop. I could find nothing about it online, but I guess it’s an RF amp tube judging by the input/output connectors. Anyone know anything about this bad boy?

The more I read and learn, the more I realize I don't know... I'm looking at building a new set of speakers, which feels like a major undertaking for how little experience I have in this space. I do not have an EE background, and so I feel like I'm constantly doing a ton of electrical and physics catch up just to start learning about drivers and crossover design. I don't have any testing equipment, and I'm unlikely to be able to buy any any time soon. I have decent woodworking and finishing skills, so the cabinets themselves are a non-issue. I have built speakers before: I'm still listening to a set of Jeff Bagby's RS180 MTMs I built in 2010ish. But after that I somehow completely shelved my interest, and am only just getting back to it now...

A few days ago I felt committed to a single woofer, if for no other reason than WAF. Paul K has been extremely helpful in designing something like an MLTL enclosure for a single Seas ER18 woofer.

But now I'm considering an MTM or TMM. One design I'm considering is something like Paul K/Dennis Murphy's ER18 MTM, but with the Sea DXT tweeter instead of the Fountek ribbon. Another way of looking at this is to say I'm considering Mark K's ER18/DXT speaker but with another woofer. I'm working my way through the "designing crossovers without testing equipment" thread, but it's a long one...and again, my EE understanding is what it is, and it is somewhat limited.

Can someone make my life easier and put me on the right track? Should I be looking at redefining the filters on the MTM design to suit a different tweeter, or adding a woofer to Mark K's design? Or would I start from scratch in designing a new filter? I would like a bit of a challenge, but I'm currently feeling a little too challenged. 😉

Hallo liebe DIY-Leute,

Wer von euch hat verlässliche, verlässliche Erkenntnisse, wie sich die beiden Reflexgehäuse für den MA 10.3 klanglich unterscheiden? Aber bitte nur gesicherte fundierte Kenntnisse!! Anhand der Zeichnungen lassen sich die baulichen Details einschließlich der Volumina eindeutig ermitteln. Die Ausrichtung von Scotts „Simple Reflex“ für das 10.3 ist Fb = 40 Hz, F3 = 44 Hz mit einem Volumen von rund 17 Litern und Daves „Classic Golden Ratio Mar-Ken“ für das Alpair 10.3 mit einem Volumen von rund 14. 7 Liter. Aber der Klang/Eigenschaften. . . . . . . . ??

Allerdings dürfte in der heutigen teilweise übertechnischen „Audiowelt“ viele „Audio-Jünger“ von der Bezeichnung „Simple Reflex“ abgeschreckt sein, da die Gleichsetzung mit „gut“ oft kompliziert ist – frei nach dem Motto „viel hilft viel“ was dann zu einer Raketentechnik wie Wilson Audio WAMM Master Chronosonic führt, nur weil man meilenweit vom klanglichen Optimum der Punktschallquelle entfernt ist und dann wieder kompensieren muss. Vielen Dank an Scott für diese Einfachheit!

Diese Frage richtet sich natürlich auch an die „üblichen Verdächtigen“!

Vielen Dank für eure Antworten und ein schönes erholsames Wochenende.

Grüße Stefan

......

I came across this picture while searching grounding articles. Supposedly the anti parallel diodes and x2 capacitor protect from EMI while still providing ground protection.
Any thoughts on incorporating this on a tube amp?

This is a big forum with lots of members and the chances of someone having an answer that can be useful is therefore high and this one is regarding Marantz PM-11S3 (integrated) vs Marantz SM-11S1 (power amplifier). According to Marantz themselves, these two amps are complimentary to one another and use very similar approaches. Both use the HDAM SA3 as an example, deliver pretty much the same power and so forth.

But I still want to ask if someone has dealt with both and can inform me of if there are any discernible difference in the in the performance arena that I should be aware of ?

Sorry, it’s just about this one, and from the smartphone there’s no preview …
This should be in every city…
https://www.facebook.com/groups/Ele...k/2268938506628805/?mibextid=rS40aB7S9Ucbxw6v
But probably in Tokyo only. Someday I‘ll get there

hello all,

i need new speakers, so i want to ask your opinions about this 2 DIY Kits.
The baffle at the ekta grande looks like a promise for a good soundstage.
The 7741 use the newer illuminator chassis.

Ekta Grande

Ekta-7741

i want to go for passive xover this time, even i own a pair of hypex 123 amps which would reduce the cost.
they are a good tool when its comming about making the xover fast and easy and active speakers are always great,but aside of this really big benefits im not so happy.

My room> 5,22m in lengh and 3,85 in width
the speakers are placed left and right of a lowerboard where a 65" TV is. (yes,not perfect, i know it has an impact on the reflections)

on the ceiling i have 18 pcs 50x 100cm Basotec panels which are 5cm thick.
on the opposite site of the speakers is the couch and above that a 240cmx140m acoustic picture which is filled with 5cm basotec panels.
so the treble is well damped, maybe a little to much 😉

Music, well all kind music except jazz.(classic is really rare, maybe one or 2 times in a year.

what i like on speakers, details and more details, a good seperation between instruments.silent things to hear that get lost on cheap shoutboxes.

my past system was a 4 way active seas excel system. with an 35cm baffle.

So, what do you think are the pro and cons of those 2 Kits ?

I have a couple of these jacks, and want to get some more.
I'm pretty sure I bought them from one of the usual suspects, but I probably don't use the right terms because I get no hits.
How are these called at Mouser, Digikey etc.
(Yes I should have kept the label ...).


Jan

Not used to hifi but designed and built >10 guitar amps.

I’ve got a quad of matched 807’s. Is planning a stereo amp build for my jazz and classical (also some metal) loving son for vinyl playing.
Was initially thinking of a regular pp amp but since I had a quad I was thinking stereo. Been searching the net and found the heathkit series and Stancor.
Do want to take advantage of the coke bottle style so want to skip the 6SN7 and run 6F8G’s (two 6J5’s in one bottle) instead Then I realized that I had 10 pieces of JAN 7193 tubes (one 6J5 but top capped grid and plate). Would look way cooler with eight 7193 up front and the heater current draw is 0.3A (half of a 6F8G).
Regarding the 807’s I was thinking a Vp of 400-450V.

So my questions are:
1) a stupid idea?
2) triode or UL operations? Do not need +70W output
3) have this PT from an old PA amp, will it be sufficient? I can always add an extra filament transformer. Will this PT work?
4) the PT does not have a 5V winding and read that an indirected rectifier tube (like a 5v4 or gz37 if preferred). Any way of getting a 5V output from one of the windings?
5) What are the optimal OPT’s for such a stereo amp. With regards to wattage. Frequency response I was thinking 20Hz-20kHz. Could get a custom made toroidal OPT with or without a UL tap for fairly cheap. I do have one 40W 6.6K:8Ohm as
of now with hifi specs. Is stereo really needed?
6) a choke and what would the “optimal” inductance be? Due to the rectifier choice?
7) any drawbacks with using two 7193’s instead of one 6F8G?

If anyone has a similar schematic for a PP hifi amp it would be very much appreciated.
I’ll attach the schematic from where I could get the PT from.

Hi everyone .
when you enclose a speaker in an enclosure the rear surface radiates the waves inside the cabinet and after bouncing, a certain part of them come back and hit the speaker membrane.
a fibrous mass or a pyramidal sound-absorbing panel is usually used to solve the problem of standing waves but is it an optimal solution to also solve the problem described above? or are there other methods and tricks? .
bye thank you .

Hello,

I have a Parasound A23 amplifier. It has several relays, can be started by audio signal, 12V trigger or manually. I give this precision just in case.

When plugged to the mains you have a P with red light.
When started you have Two blue lights in front.
You also have a Temp light which is always off.

Now the problem.

Amplifier stays online for several seconds or minute then it can :
A switch off the output and the blue lights
B switch off everything including the red light. In that case you have to unplug from the mains and plug again.

I opened the amp. All fuses are intact. nothing looks burnt.

Dont know what could be the problem or what I shall do.

Any thoughts ?

Regards, Greg.

If you don't know what is current dumping, you really need to search on the forum and learn it. In short, it combines a small current Class-A output with the final output stage. You can get Class-A performance even with zero biased final output stage.

Here is the design for my future reference.
THD 0.001% at +-23Vpp into 4 Ohm.

I'm adding a DC power supply plug to a DAC I'm making. Which size is the most common?

I've seen Outer Diameter = 5.5mm and Pin Diameter = 2.1 - 2.5mm. My Graham Slee Ultra Linear PSU seems to be using 5.5mm and 2.5mm, but I have heard of other sizes being common, too.

Thanks,
Børge

Title says it all - your offers please ...