Allow me to proudly show off my newly scratch-built multi-impedance headphone amp.
It uses 12AX7 drivers and E88CC power tubes running in an SSRP configuration, driving Sowter type 8665 headphone OPTs.
It can accommodate phones from 30-600 Ω via two selector switches on the front which I nicked off from a guitar website on switching the pick-ups (humbuckers?) from series to parallel, etc.
It sounds great with my 70Ω Sennheiser 599s with great bass and hi-end extension and has plenty of power.
It's also dead silent, once settled down after switch-on, partly due to the oversized PS, partly due to use of Broskie's "Akido Mojo" on the SSRP power stage.
I avoided the use of electrolytics in the signal path apart from the "mojo" sub circuit which injects a portion of whatever noise remaining on B+ into the SSRP stage's cathode, thereby cancelling it's amplification (active noise reduction).
Lastly, I chose the hammered green finish as a nod to my old school's AV equipment - 16mm and filmstrip projectors all seemed to have this industrial look - hell, even the pencil sharpeners!
Very happy with my first scratch build.

It seems tables aren't rendered. When I try to insert a table, I get some HTML-like mock-up code. The table doesn't render. MacOS, Safari 15.2.


Tom

Will I run into any clock sync issues if I daisy-chain more than 2 consumer S/PDIF devices?

I'm asking because I was reading the manual for an audio interface and it said not to daisy-chain digital audio devices without dedicated word clock connections. This made me wonder about consumer S/PDIF applications involving more than two devices. Obviously consumer-oriented devices almost never include word clock connectors, however there are products that can be daisy-chained.

For example, my FiiO BTA30 Pro has S/PDIF passthrough so you can have a setup like [Source] -> [BTA30] -> [DAC] all connected in series via TOSLINK. These will all sync properly, right?

I have one sitting around, and need suggestion which kind of box to make. Currently is in 45 BR build for in car use, needless to say, placed in house, it sounds like ****.
I'm using it to make noise while watching movies.

Can someone, by looking at attached parameters suggest what to do. I would like to keep it as HT SW.
Thanks

I've got two toroidal transformers, each having 2x40vac windings, left over from a past project. I'm going to use them in a new power amp project for which there isn't really a need for separate transformers (one bigger one would likely have been more efficient), so I need to decide how best to assign them. Their job will be powering a pair of 3-way speakers with active crossovers (so 6 amps total), but with a twist - the midwoofer+tweeter cabinets will be separate (from the bass cabinets) and sometimes used alone as 2-way speakers.


Tentatively in descending order of my preference, but it seems a bit arbitrary.. so I'd be interested to hear what other people think about the choices or if anyone has better options?
Cheers, Kev.

I have a Strat knock-off with a pickup on the bridge springs to create a spring reverb type sound. The only problem is the spring pickup level is considerably lower than the other pickups, so if I switch it on with another pickup, the regular pickup's volume is essentially halved. Is there some type of preamp setup I could use so that switching the spring pickup on would just add a low level reverb sound on top of the regular pickup sound?

I bought a pair of these a while ago and want to make a bedroom MLTL mini-towers for them. Intended use case is 2 channel music at bedroom levels.

This is the driver

Dynavox LY302F 3-1/2" Full-Range Driver

This is my first time using hornresp, so I appreciate any feedback







Thanks!

Folks,

I have 10 AD1862 dac boards and PSU2 boards to give away (ie 10 packs of 1 1862 board and 1 psu2 board). I got extra made when me and some fellow diyers here were making the DACs. I had anticipated needing more spares but the builds went so smoothly none of the spares were needed.

The DAC boards are V1.3 with through hole opamps as shown in this post:
https://www.diyaudio.com/community/...2s-input-nos-r-2r.354078/page-68#post-6488132
The PSU2 boards are v1.0 - LT1963/LT3015 version as shown here:
https://www.diyaudio.com/community/...2s-input-nos-r-2r.354078/page-74#post-6530277BUT bear in mind there is a change in resistor values to hit the target voltage:
https://www.diyaudio.com/community/...2s-input-nos-r-2r.354078/page-78#post-6551192AND a recommendation on 2r2 resistors on the rails:
https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-104#post-6676470
I've been extraordinarily blessed with PCBs for builds from here, plus I enjoy this DAC almost every day. So I want to give these away/ I'll post anywhere in the world for free (untracked), but would ask that you do a 5e donation (about the cost of postage) to diyaudio given we all get some much from here.

Fran

In opening the amp up to adjust bias, I noticed there is no thermal grease applied between between the mica insulators and output transistors.
Thermal grease is present between aluminum substrate and heat sinks. Is this what you would expect to find? On other amps I've always found
each output transistor having thermal grease applied for best heat transfer. Thanks

I have the a power transformer with a 6.3v 5A non center tapped winding I was planning on using on a TSE-II board with 45 tubes.

Can I use it or do I need a center tap? If so, can I create a virtual center tap?

Right now I am getting 0v on pin 4 of the power tubes, with T1-GRN-1 and T1-GRN-2 receiving 6.3v.

Thanks!

Howdy,

I posted a similar question in a guitar amp forum, but I have not had success in getting any answers and am wondering if anyone here might be able to help.

I have a Leslie guitar speaker cab from the early 70's - it is basically a speaker cab with a rotating drum that spreads the sound vertically and to the sides at either a slow or fast speed. You would hook a guitar amp up to this cab and also to another speaker. Highs and lows were passed to the "regular" speaker, while the rotating speaker got more of the mid range. This was done using a cable assembly that included an inductor and capacitor wired in parallel - effectively creating a notch filter for the "regular" speaker, and a capacitor in the Leslie cab which would act as a high pass filter. I have not been able to find pictures of the inside of the cable assembly, but based on its cylindrical shape (bottom left of the attached picture), I am inclined to think that the inductor was perhaps a cylinder shape with radial leads.

Anyway, the reason for my post is that I do not have the crossover cable assembly. I'd like to build the crossover into a metal enclosure (basically a guitar pedal), but I am struggling figuring out what type of inductor to use. Using an oscilloscope, I ran my guitar amp at my usual volume through a 4 Ohm dummy load and measured ~13Vrms at 400Hz which I believe thus implies ~13/4 = 3.25Amps were running through the load at this frequency. In looking at radial ferrite core inductors, it seems like their current handling specs are usually nowhere near 3 Amps for the inductance values I would need (see below). Air core inductors seem popular for use in stereos, but they seem somewhat impractical to mount inside a guitar pedal.

Is my reasoning with regards to the calculated current flowing through the circuit logical? Is it critical that the inductor be rated for this level of current, or is it unlikely that this much would flow through the inductor alone when in reality guitar signals will always have multiple frequencies (including harmonics) and thus the current would be split and also flow through the capacitors (one parallel to the inductor at the "regular" speaker, one high pass at the rotating speaker)?

I have an 8 Ohm speaker in the Leslie as well as in my amp, and I am looking to use a 100uF cap at the rotating speaker to act as a 200Hz high pass filter, and then a ~2.4mH inductor and 1uF cap in parallel for the notch filter going to the "regular" speaker.

Any thoughts as to what I should be considering for the inductor? Is air core the way to go, and I just need to get creative in terms of mounting it inside the enclosure, or are there options for ferrite core radial inductors at these values?

Thanks!

Greetings Fellow Tubaholics,

My name is George, and I have been tube-free for...
well, I *haven't* been tube-free. ; )

As further introduction--I am a relative newbie
looking for a DIY amplifier project of about 50WPC and
fantastic sound. By "fantastic", I mean those
subjective tube euphonics of openess,sweetness,
and holography.

As I have searched about, my eye has come upon
the designs of one Menno Vanderveen (or van der Veen ),
a proponent of new topologies and torroidal OPTs.

I am intrigued by his new PP designs, particularly
his Super-Triode, as described in this article on the plitron site.

This design uses both Ultralinear and cathode feedback,
and recommends SV6550C tetrodes.

As far as I can see, the potentially controversial aspects
are the new topology, and torroidal transformers. I
have no insight into the topology, but it seems to me
that the torroid offers extreme linearity and bandwidth,
at the expense of sensitivity to DC current saturation.
However, the design offers DC adjustment, so is it true
that this would not be a problem to the conscientious
tweaker?

What little comment I have heard on his designs
is positive, but I would like to get your advice
before I leap.

So I would greatly appreciate your opinions, insights
and preferences. Do you think this is an excellent
design? Why isn't it more popular? What DIY 50WPC
DIY design would you recommend to a builder seeking
excellent sonics?

Although this is my first post, I have enjoyed
reading your friendly and insightful posts. Thanks
in advance for your help.

Happy Tweaking and Listening!

George Ferguson

I have a pair of JBL 2225H, 2205H & LE8-t woofers. I've only just acquired the LE8-t's but I have been inquiring on designs for each as I got them, but now since all are at me (design disposal) I have questions on OB designs. #1 Do hybrid designs integrate well in the crossover portion? #2 Does the bass response of a non-hybrid design equal the performance of a hybrid? #3 Will the use of these three woofers create a problem for a low power tube amplifier? Please Note: This image is not my creation and I only take inspiration from it!

Can anyone tell me if Oddwatt is still offering kits? There website is shows kits available, but I e-mailed them without response and the phone number listed doesn't work. Thanks for any information.
Mike

Good evening,

This Rockford power supply uses MMBT3904/6 transistors as buffers for the gate drive. I'm out... so is Digikey and few others. They are 40v .2A devices.

I do have MMBT4401/3 (40v .6A) and MMBTA06/56 (80V .5A).

Can I use the 4401/3's? What are others using in place of MMBT3904/6?

Thanks!!

Hi, I got a stereo tube amplifier for repair. 2x(4xEL84). Some sparks of tension has taken place, burned places on the circuitboard. I have measured the output transformer for self-induction and now it appears that they show about 30% deviation. From anode to anode, one is 6.8H the other is 4.2H. Is this normal ? or is one transformer gone ?

I am planning to build a subwoofer according to the drawing below. The closed part is W x H x D = 60 x 40 x 40 cm. The design with the open parts above and below the box for interior design reasons, not for acoustical reasons. The curved front is also a requirement for interior design, although it should be beneficial for acoustics as well.

Now I wanted to mount the woofer (30cm) in the bottom of the box. Also for aesthetical reasons.

I am wondering if the lower open space of the cabinet will cause resonances. After all, left-right it is a closed pipe of 60 cm length and front-back it is an open pipe of 40 cm. The height of the space is 16 cm.

The formula for resonance in a pipe is n v / 2 L. Where n - 1, 2, 3 ... ; v = speed of sound, L = length of the pipe.

In left-right direction the resonance frequence would be 280 Hz. The subwoofer amplifier has a filter at 80 Hz, 12 dB/oct. A frequency of 70 Hz is attenuated 24 dB, but if the pipe is resonant you should be able to hear that.

Or does this open space not behave as a pipe at all?

Number Two: He is exactly like you in every way...except one-eighth your size.
Doctor Evil: Breathtaking...I shall call him...Mini-A

Yes, the exciting, new, pocket-sized Aleph. Use it for your Walkman, use it in your car, you can even use it for a hand warmer! Approved by none other than that arch-fiend, Doctor Evil.
What Austin Powers thinks, we aren't sure. He's off testing his mojo with a fembot.
But seriously, folks...
A couple of months ago someone brought up the idea of a small amp. Now, yes, you could build a Zen, or you could build a Son of Zen, or you could build...oh, never mind, it was build a miniature Aleph or bust. I was okay until I realized that I actually could find a use for such a creature. (Really I was. No, really. This twitch? I always twitch like this...) So I started thinking about a self-powered, biamped speaker using a couple of nice drivers that I've got sitting on the shelf gathering dust.
And as I've said before, I'm happy as a clam until I start getting to thinking about <i>how</i> I might go about something. Once that happens, I start muttering to myself, scratching numbers on scraps of paper, wandering off to work without clothing on, that sort of absent-minded nonsense.
Blast it, the Mini-A grabbed hold of me.
I hereby release a Version 1.0 schematic of the Mini-A.

And now, a word from our sponsor...

The usual disclaimers apply:
1) This circuit is covered under US Patent number 5,710,522. For those of you bright enough to pound sand, you'll realize that this means that Nelson Pass owns this circuit just as surely as if he had penned it himself. If you build this critter for profit, seventy-seven lawyers will knock on your front door tomorrow morning and cause you more grief than you can shake a stick at. By the time they're done with you, you'll wish they still did things like they did in the good ol' days when they were content to visit a plague of locusts on your tomato plants, or sic a rabid Chihuahua on your ankle. Nope, we live in modern times now. There are new, high-tech ways of making you suffer.
So don't even think about it.
2) This is a first pass (no pun intended) at producing a little feller. I recalculated some of the obvious things, but left a few others alone. Suggestions for improving the circuit will follow. I've built a breadboard prototype. I tested it on the bench. There's no circuit board to go with the schematic. There's no warranty, expressed or implied. Your mileage may vary. In other words, I drew the schematic a month ago, finally got time to start building it yesterday afternoon, finished this afternoon, and have found that it works. I'm sure that there are a few more things that can be optimized, but it'll run as-is.

So why build a dinky version of an Aleph? Doesn't everyone want more power, not less? Aside from the powered speaker possibility I mentioned above, let me kinda rattle your cage with the following suggestions:
--The suggested rails are +-15V. It draws approximately 1A. Remember that transformer in the corner you've been trying to find a use for? The one that wasn't big enough for anything else? Smile, little orphan trannie, it's your day in the sun...
--Okay, so you plunked down the big bucks for a bag full of output MOSFETs for another project, and now you've got leftovers that you don't know what to do with. Yeah. You guessed it. It's showtime for those little puppies.
--Want to experiment with battery-powered amps? Two ordinary car batteries and you're set to go.
--Sick and tired of the device matching problem? It sometimes seems like it's harder to get a date for a MOSFET than it is for a human. The output devices for this amp DO NOT need to be matched. Cool, huh?
You get the idea.
All right, let's discuss the circuit.
It's a cut-down version of an Aleph 3. I arbitrarily chose 15V rails, but it will work nicely as long as you're within shouting distance of that voltage. 18V? No problem. 12V? No problem. Just keep in mind that it's a class A circuit and it will demand roughly an amp at idle, every day, all day. Don't try to run it off a wall wart. (Yes, I know it's tempting. Sorry to spoil your fun.)
So what's it put out?
About 5W without being refiddled. My calculations suggested that it should swing a little over 9V RMS (this would translate to about 10-11W into an 8 ohm load). In fact, it comes out almost exactly that as long as I use my oscilloscope for a load, but comes up a bit scant (around 6V) when I put an 8 ohm load resistor on it. A little more bias current would probably be a good idea. Go back and look through the threads, there's been plenty of discussion of bias in Alephs.
Other things you might consider doing include putting Zeners on the input to stop little lightning bolts from eating your front end's lunch (my little test rig here likes living dangerously--you ought to see him dressed up in his little black leather jacket, ready for a night on the town). You might be able to re-jigger the feedback ratio (R6 vs. R8) to optimize distortion (this will also change your closed loop gain, so be careful). You might wish to recalculate R13. Unless I've slipped a cog (not unlikely, actually, it's late and I'm tired), this sets the threshold at which the protection circuit kicks in. It may be right, it may not. I didn't really take the time to mess with it. And last, but not least, you could graft the whole Volksamp-Aleph front end onto the thing.
I trust you can handle the math to put an LED on the critter so that you will know that it's on.
If you've studied the Aleph circuits at all, this circuit should be pretty much self-explanatory. The idle voltages will all read about the same as the real Alephs:
--About 4 or 5 volts across R4
--9V across D1
--Roughly +4 volts at the sources of the front end differential, relative to ground
--About 4 or 5 volts across R3
--About 4 or 5 volts across Q4
Power supply?
What have you got on hand? Just stand back and throw some parts at it. It'll work.
I'm embarrassed to tell you what I've got on this thing. Let's just say that it's running fine on a small transformer (estimated to be 100VA--not even warm to the touch) with a junk box bridge rectifier, and some pretty small caps (30000 uF each rail). More would be better, and I've got some fairly hefty caps on hand (about this time it will belatedly occur to someone that they can use those monster 1 Farad caps like you put in cars for this circuit), but it isn't something I'm going to spend a lot more time on.
Why?
Shhh...
Listen...
Hear that?
I hear an Aleph-X calling. Gotta go.

Grey

Oninions ?- Transmission Line over Reflex and Acoustic Suspension ?

Hi. I posted a previous inquiry in reference to building a pair of TL speakers in the design of a narrow, tall, column tower design.

I am somewhat inexperienced in TL's other than assisting my brother in duplicating an existing design in a publication by David Weems, " Great Stereo Sound Speaker Manual with Projects." We did this some time ago, around an inexpensive Pioneer 6-1/2" translucent woofer driver, a cheap Motorola piezo radiant tweeter, and a simple crossover.

The sound, from my recollection, was astounding, and unusual for such an inexpensive design and small woofer. The reason we did it was experimental, and they delivered on the promises Weems made about them. Anyway, my brother is still using them in his den.

I also had the opportunity to hear a pair of Vandersteens, when invited to a friend's boss' house for a party several years ago, and recall many people (myself included) marvel at the warm, depth, clarity and imaging of these amazing speakers.

I had a similiar experience listening to KEF s and Soliloquoys, among others on other occasions, and really felt they had a beautiful sound by comparison to other quality speakers I've heard over many years, and cannot describe the apparent difference. For this reason I have taken a serious interest in unusual designs such as Voigt pipes, tapered lines, labyrinths, folded horns, etc.

Would any or most of you agree that they are sonically superior by design ? Does anyone have different views regarding TL's ?

Most of the material I have been reading regarding TL theory suggests these designs are superior and capable of producing bass down to a woofer's given free-air frequency, and do not impose limitations on the woofer that inhibit clean, natural, uncolored bass, particularly in the upper and middle-bass frequencies. Advocates of lines all seem to unanimously agree that they beat all other designs on all counts. (Efficiency, lack of coloration, depth, etc.) Often they condemn acoustic suspension designs for pressure buildup in one side of the cone, and vented bass reflex systems for "ringing", and port noise, etc.

Just interested to see what some of you out there, think, in your honest and professional experience and opinions.

I'm wondering if it is worth all of the effort to build such a large enclosure, when many cite I could obtain the same reults in a smaller, less expensive, less time (and space) consuming box.

I truly appreciate any of your opinions, value your DIY experience, and your willingness to share your knowledge.

Thankyou. Warm Regards, Eric

What are recommended flush cutters which will not dull or be damaged by modern steel lead components?

My existing flush cutters still cut most of the leads but the accumulated damage is more and more visible on the cutting surfaces.

Hello.

I have a 4-way active stereo system, currently with Hypex UcD400HG driving midbasses (18" OB, 8ohm). I'm thinking of upgrading the midbass amps and use the UcD modules to power two additional subs. Top options so far for midbass: IcePower 1200AS1, Hypex NC400, Hypex FA251 or FA501, or might as well wait some months and get a used LSA Voyager/Peachtree GaN amp. The DIY modules allow for building into the DIY speaker and get them out of sight, though.

The search is in the context of nice tube/SET amps for midrange and treble and very good digital to analogue conversion. The amp will be used in the 80 to 500Hz range.

Focusing on Hypex options, looking at the Fusion Amp manual I noticed the FA251 and FA501 have an ADC>DSP>DAC sections between the analogue in and NCore. I do digital xo/DSP further up the chain, so don't need this here. Old school preconceptions skew me towards thinking these sections likely aren't better than a plain analogue into a NC400. Yet the FA modules are so convenient with all-in-one construction and turn-on upon input sensing...would be so much easier🙂

So I wanted to check with those who have heard FA and NC amps if the ADC>DSP>DAC degrades sound in any shape, since I wouldn't really need those capabilities for my application?

Thank you!

Hammond 290YEX power transformer. 240VAC, 2x186V @ 400mA CT, 56V bias winding, 6.3VAC heater winding, drop-in type.

It is sold by Hammond as a Fender Bassman 70 PTX, also Fender 75 Lead.

Bought in error, never powered up. Location Melbourne, Australia.

Offers.

While waiting on a delivery, for some entertainment value, I watched a slew of "experts" present their list of magical tweaks one can to to make their average music system the greatest ever. Done with a strait face, providing copious verbiage of soundstage, details, depth, life, and every term a thesaurus can provide. Most of these looked to be actual believers, not paid shills. Most seemed to not have paid attention to grammar school science class either. Concepts like AC seem to be totally amiss.

Anyway, it got me thinking. As DIY we want to tweak and do as well as we can. What kinds of things that don't violate the laws of physics and could be measured under laboratory conditions can we do? In no case do I suggest anything is audible or not. Just possible and with at least a thin grasp of reality. I try to suggest the actual parameter that the tweak could effect. A few of these fall under the old POOGE concept, which are internal tweaks. Several of these are only possibly relevant if poor design inside the box. Always think about any modification and if it is reversible. I know of an instance where someone potted a phono board to reduce micro-sonics, but the encapsulation caused it to overheat and fail.

Please, do not extend this to your favorite legless reptile extract claims. If one of those makes you happy, then I am happy for you.

I list tweak and possible effect. In no order than my pontificating. If you have some that fit to this list, please share them. If something in my list fails my criteria of possible, identify it.

Speaker position. We understand that one. Reflections within two feet have a significant effect on localization. On vs. off axis to the tweeter has a big eq effect and so on. Pointing in can reduce outside reflections. Or not.

Sound management. GOOGLE same and see what can be done with tips how to DIY. If it meets WAF, ( I guess we need a new term to be politically correct, "domestic distortion factor", DDF? ) great gains. Blew my mind after doing work in my last house HT the first time a sound came from left of the speakers. All hail Owens Corning 705. Management with intent and understanding, not blanket absorption.

Steel out of signal path. Fuse caps and holders, nuts on binding posts, cheap relays, chassis ground points. All can cause parasitic non-linear inductances.

Ferrites on line cords. Yes they can reduce RF. Can't do any harm. May reduce stray RF in proximity.

Twisted line cords. Most are already. Again can reduce stray fields.

Polarity of line. In the US with our polarized outlets it should not be a problem, but I have had older equipment without polarized plugs. This can cause hum in the system. If a US 3 prong, it may blow the breaker so you would know it.

Line/surge filter. More of a safety device. I have had proximity strikes take out electronics.

DC blocking filter. Big toroid's can get upset by DC and cause audible buzzing mechanically.

USB isolators If you have a lot of hash, and if the DAC is not well designed, and if USB powered, yes they filter noise and protect against transients. If your DAC is USB powered then a very clean external supply into a isolated hub can be cleaner.

Twisting speaker zip cord. It will reduce RF pickup so if your amplifier does not have a proper output network, it is possible to feed back into amp and cause instability. I actually had this happen. Bad amp design and an illegal 1000W CB transmitter.

Ferrite on speaker cord Same as above.

Pure tone sweeps of your listening room. Looking for things that resonate. I had a window spring and back of display case get excited. Some stands can be filled with sand as they may resonate.

Keep speakers from rocking I use a bit of rug anti-slip, but rubber feet or blu-tac work.

Quality of passive parts, particularly in crossovers Film rather than electrolytic caps, air core inductors. If in series with the woofer, wire gauge could actually effect the transfer curve. Non-inductive, non-steel resistors etc. ( funny, actual engineer with a strait face talking about coil resistance is series with a midrange, in series with a resistor!)

Low pass filter on the tweeter This may reduce artifacts that can excite breakup, mostly on metal or ceramic type tweeters.

Sub sonic filter on the sub Prevent excessive cone excursions below Fb.

High pass filter on the mains Prevent excessive excursion below Fb.

Redundant coupling caps. At your own risk, if you know for sure your preamp is AC coupled, then the input coupling cap of the amp is redundant. Evaluate your system as a system.

Too small a coupling cap. Many are picked only for the pole. Going much larger in an electrolytic can reduce distortion. Where maybe a 2.2u, use a 20. Self discussed this I believe. ( or I might use a 1u film)

Proper EQ in the room. This should be obvious. You can EQ your room, smooth the bass and solve any small speaker anomality, and get the top end rolled off enough for reality.

EQ per recording. Possible with great effort and big gains if you are a better mixing engineer and if an overall eq helps rather than the eq per track they did in the studio. Good luck. Some older "right and left" mixes, early 60's, can benefit for some top end mix like you may do for headphones.

Different EQ for every headphone. They are all different. Often quite a bit.

Clean connections Older equipment with tin plated RCAs, switch contacts, etc, a de-oxit I actually suggest dielectric grease on these locations to exclude oxygen and moisture. Actually some modern gold plated, the gold is so thin, the copper oxide can bleed through, so cleaning things up never hurts.

Clean the dust off your heat sinks. Kind of obvious isn't it?

Check for PS caps getting old. If you can hear hum right at your speakers, or even feel it on the cone, might consider if your big electro cans are getting old and dried out. Might consider replacing with a multi-cap array. Cheaper, usually longer lasting, lower ESR, and you may be able to fit considerably more capacitance. If you do, pay attention to the rectifier and inrush current. Many amps only have enough filtering to reduce noise, not to keep the rails up on transients. "Dynamic compression"

Clean you ears Yea, some actually get a build up and don't notice it. Your Dr. should notice it in your annual physical.

Noise from florescent or cheap LED lights. Both audible and RF.

Sound control in HVAC I hate flex duct as ductwork, but they don't transmit sound as much as hard duct.

Take all your audiophile magazines to the recycler. Don't pollute your mind with bogus wild paid advertising. I exclude things like Liner Audio as it is real engineers talking about real engineering. Voice Coil, ASE, Polish Institute etc. For what subscriptions to the slick page advertisements cost, you can go to the symphony many times.

Spurious sounds. I need to but some absorption material behind my all-in-one music server PC as in a quiet passage, I can hear the fan. When I ran a Behringer PA amp to my subs, I had to modify the cooling to eliminate the noise. Sit in your room and listen.

Correct length cables. No need for a 5 foot cable if units are 6 inches apart. When we can get just about as good as it gets from WorldsBest, or BlueJean for a few dollars, why not? If a cable is bad, then less of it is good.

Dress your cables But distance between power, speaker and interconnects. Cross at right angles. This reduces coupling.

Space between components. Especially if toroid transformers as their fields are usually vertical and can induce hum in a unit sitting on top. Also can help cooling. Go for several inches.

Go hear live music. Funny how we forget what instruments actually sound like. Have some fun. Take something that makes a nice sound. Big pot lid maybe, cymbal, strum a guitar. Set up your instrument mic and record it in the same position as one of your speakers. Then play it back. Listen to see how much work you may have to do! ( or not)


PS:
If your esoteric speaker cables, line cords, USB, and interconnects were made in England, send them to me and for only $1000 each, I will lay them before my Triumph Stag and perform the ritual to excise Lucas, Prince of darkness from them and return them in said pristine condition. The same ritual seems to work on Smiths as well. For an additional fee, I will put them in my pressure chamber and re-infuse them with magic smoke. Due to import and supply issues, bottles of magic smoke are in short supply so some delays are possible. I had a good supply collected from my MG, but used it all up. There may be services to excise the Italian, French and German electrical daemons, but I only deal in British. 🙂

both power and protection leds keep blinking ..all output transistors good ..driver card good...capacitors connected to the output section good ..any body ever fixed this problem??

Hi. Dali Rubicon 6, have a special edition (Black Edition) where the caps in the signal path for the tweeters is changed to Mundorf M-Cap types from bipolar types.

I have a set of Rubicon 2 (and LCR) where i would like to upgrade the caps to the same type. I am surprised to see bipolar in the signal path for the tweeters, as normally way back Dali used film types here, even for the cheap speakers. Dont know, perhaps its to separate the Rubicon from the Epicon series, as the tweeter is excact the same, and only very small change to the woofers magnetic system.

Is that a good idea to change from bipolar to film? (seriously i havnt ever had a bipolar cap in a speaker before lol)

Was wondering if only those in signal path for tweeter is good to change or also perhaps the big values in the woofer section. I can see, the crossovers is some variation over simple 2 order type.

The values from the bipolar Bennic, is easy to find excactly as Mundorf. Space might be a bigger problem especially for the woofer section, and i dont know if its worth it here.

Anyone with some silimar experience chiming in?

I just pulled these out of a sidewalk find.

Do I chuck them or are they worth the time to put into a project like an DIY ebay PCB and throw away the supplied fake chip?

I think the -230 is a 2ch 100w, but the top one -040 is a 3ch 30w

https://www.ebay.com.au/itm/125089807239
https://www.ebay.com.au/itm/263372057529
https://www.ebay.com.au/itm/363213322703

Norma Waterson.
Another sad loss.
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A ribbon dipole tweeter reduced to the bare essentials that works and measures surprisingly well.

This is my third attempt at building a dipole ribbon tweeter, the first two used steel frames for holding the magnets and closing the field. This time I decided to drop the steel frame in an attempt to reduce the width of the tweeter as much as possible.

Dimensions are in millimeters. Thickness is just 9mm. What looks like single magnets are actually two custom N52 4mmx10mmx40mm magnets glued on a 1mm thick frame of aircraft quality plywood.

Using two magnets separated by a non-magnetic material results in a much more even flux density across the gap.

FEMM was used to simulate the flux density across a 19mm wide ribbon in a 20mm gap. The red line represents a single N40 (standard) magnet, the blue line represents dual N52 magnets with a distance of 0.5mm and the green line represents dual N52 magnets with 1mm distance. With the single magnet the maximum is much higher and located on the outermost edge, if you wanted to flex the ribbon this would be ideal. With the green line the difference between maximum and minimum is much less and the maximum is also located about 1mm from the edge, less corrugation will be required to prevent flexing of the ribbon.

The ribbon itself is made from 10µm household aluminium foil etched down to about 5µm using a diluted sodium hydroxide solution.

The foil is cut to size using a roller cutter and corrugated with this simple contraption

It’s even called ribbon cable Duh. The trick is to have just the right amount of corrugation, too little and there will be serious distortion, too much and you’ll get resonance problems.
How to drive this ribbon? Normally a transformer is used with this kind of (small) ribbon, I decided to try the brute force method with a series resistor and lots of power to see if this could work.

A Hypex NCore400 and four 0.5Ω 100W Caddock resistors. Not what you’d call an efficient approach but there are some advantages.
- The amp sees a nearly perfect resistive 2Ω load.
- Small variations in the contact resistance at the ribbon do not matter.
- Thermal compression is not an issue as the resistance and thus current is determined solely by the resistors.
So, how bad is it? Is it a space heater? No, it is not a space heater. Well, it will be if all you do is playing test tones at full power but with music the temperature of the heatsink barely rises above room temperature. Playing music very loud I measured peaks of 15A but the average was just over 3A.

Is it really a dipole? If so, up to which frequency? Next up, the measurements.

Hey All,
I bought a Douk Audio Shigeru Wada clone type cheap tube preamp and have a question.
Does anyone happen to have a schematic that might apply to this type of preamp?
Dual transformer
2 12AU7 tubes
2 6N4 tubes
4 6N2 tubes
2 6Z4 tubes
Not sure what the purpose of the 6N2 tubes are?
I have dabbled in solid state for awhile and thought I would venture in to the tube world where the voltages are a lot higher!
Thanks Steve

I've been a lurker on this board for a few years now. But since I'm now taking part a bit more actively, I thought a formal introduction might be in order. I'm a psychiatrist living in Toronto. I'm a pretty casual DIY'er, and mostly with tubes and speakers, building from plans and schematics devised by others, and have done very little with solid state devices.

I've attached pictures of my main rig, which consists of:

Nottingham Interspace turntable with RS Labs RS-A1 Tonearm, Hana SL cart and Lundahl step ups.

Hagerman Cornet phono stage.

Schiit "Gumby" DAC

Pass B1 Buffer linestage

45 DRD amp designed by Jack Elliano

Open baffle speakers with Lowther PM6A and Tone Tubby woofer per design by Jon Ver Halen when he ran Lowther America. I do find these speakers a bit light in the bass and still have some of that infamous "shout". My crystal ball tells me there is a pair of SLOBs in my future. Hopefully that doesn't just
mean my kids will be moving back in.

Thanks for having me aboard!

​

OK, so it's not that I'm giving up speaker building, but I have a boatload of older drivers that I need to get rid of. I would like to sell everything. I'm not interested in cataloguing everything. Below is a partial list, along with pictures.

Subwoofer cabinets. Nine, yes, nine. I think. See pix.
PE 8" or 10" x 2 RS series subs
PE 12" RS series sub.
OLD version shielded RS225 metal drivers. 4 New in box unused. 4 just sitting there in an never finished dipole.
Peerless 6.5" midbass too lazy to look up. Fairly distinctive from the pictures.
morel 55's pair
vifa xt18wh pair
SS 13M/8636 pair
SS 18W8535 pair (I think I bought these off SL long ago for $100 for the pair!)
SS 8555 pair. (might keep)
Philips RT8P (might keep)
OLD style RAVENs
Test cabinets
A pair of transmission line SS 3/4" and GR research M130's. M130's need to be replaced, but actually not bad drivers. Has to be good, since I designed the xover 😉
random audax tweeters with dinged metal domes. (I mean, hey, basically I'll end up giving all this stuff away if I can't sell
There's an Outlaw Audio 2250? I think. Still works, but knob falls off all the time, dramatically decreasing resale value...
There is one RS28F. I know I have another pair, but can't find it...

The old RS with Lineum tweets, well, I just can't part with those, for sentimental reasons.

The Paradigm Titans aren't really DIY, but there's thrown in there as well. At some point I was going to redo the xover, but never got around to it.

What I really want is someone to buy the whole lot for what you think is a very low price. Pretend I died and my next of kin was dumping it all at an estate sale or something. No way I'm shipping, so local pickup. If you're really just interested in one or a couple of items and want to pick up, that's ok two, although I'll wait a week for offers on the whole lot before parting out.

hope all you guys are well. Retiring in less than 3 years. Hope to pick up the hobby again with new drivers...

Mark

Local pickup only in Northern CA. (Rocklin CA)

No reasonable bid refused. I'll even consider unreasonable ones...

Really. I basically am at the point I'm going to give or throw away the stuff. Hate to toss it. Has some value.

I happen to have one of these great amps and love it. Well, until channel 3 died.

I bought it a year or so ago off ebay (!!!) and had no complaints. The seller recapped the amp (delivering all the old caps) and is much more talented than me with a soldering iron and circuit boards!

The amp stated going in and out on channel 1 and 3 (hooked up to front and rear left speakers). Now channel 1 sounds fine (don't you love irratic) and channel 3 is dead.

I'm more comfortable around tube amps.

Then looking at the circuit, I see IC603 (LA6458S). Is the purpose of this IC to invert the phase of channel 1's input signal? And there is another on channel 3? Is this something that has to do with the amp's bridged function?

I'm thinking that could be the culprit. Maybe jump pins 6 and 8 to bypass the IC and see if that works? (I don't operated it bridged, so are these IC's needed?)

I have it hooked up to a terrible 12v power source that can just manage 11.9v at idle. And it seems like the PS is just fine.

All the output transistors measure volts to ground:
B 0.6, (0.6)
C 23.6, (23.6), +0.2, -0.1
E 0, 0

Bypass LA6458S?

Thanks in advance,
Dan Perez

Hi! It's my first post on this forum and I would like to start a thread where I'll tell you my story of building full size planar magnetic headphones.
Hope DiyAudio community will be interested also I hope to hear some advices.
Fankly speaking, I'm rather new in Head-Fi (but not new in Hi-Fi and DIY 😉 ) and I hope to hear your opinion (and maybe some tips!) about my work. I've started building headphones exactly 1 year ago and now I think I have something interesting to tell to the world.

What are my goals?

1. To build a full size open planar magnetic headphones
2. Achieve a sound of a really high level ( my landmarks are Audeze LCD-3 and Hifiman He-1000)
3. Headphones should be ready at least for a small series
4. Net cost 100-150$

So the story begins...

My first step was to make a simple planar magnetic transducer. From my point of view starting from the beginning with building a headphone is a really bad idea. I'm not novice in making non-dynamic transducer: i've already built electrostatic and plasma speakers, so making an isodynamic speaker wasn't a difficult task for me. I went to market, bought same magnets, opened Corel Draw, made simple drawings and cut with laser a few plastic and metal parts.
Next day I received such result :

My test planar speaker
And same speaker with one sided magnet system:
Same speaker with one sided magnet system

If Admin will consider my post worthy and let me start the thread I'll continue to explain how to make planar headphones in details.

Hi Guys
I have tried several sites to try and download this program, but getting infected messages from my Does anyone have a safe link to download it from.
Thanks in advance.
Adrian

Hi, I would send a PM to NP, but that doesn't seem to be an option.

Out of courtesy and respect, I wanted to check if there are any guidelines and/or objections with respect to my releasing PC design files for my version of Jeff Young's reverse-engineered HPA-1 schematic. I don't think there's a legal issue, but I don't want make a problem, e.g., inadvertently doing R&D for eBay cloners.

Jeff's Kicad files have been in the wild for a long time with no apparent harm, but I want to double-check.

My only intent is to give something back to the community.

Thanks.

I have 4 (four) Purifi 6.5" passive radiators for sale. ptt6-5pr
These are in very good condition - I can't see any marks on them.
These are located in the UK - and I'd prefer to ship only to UK.
Any offers before I put them on ebay?

PTT6.5PR-NF1-01 - PURIFI

On drivers I often see a black sealant used to secure and protect bare wires and terminals, adhere metal screening or other small parts to metal or plastic.
It is quite hard and strong, but appears to be brushed on.
What is it and where can I get some?
Thanks.

I managed to make a deal with Profusion and purchase the last FIVE Tripath TDA-2500/0105 replacement boards they had!

The version I got was the 0105 version which i believe is the higher voltage version. they are the same board as the 2500 board with a couple resistor changes. But which resistors are different I am not sure. My contact at Profusion no longer had the info.

these boards were drop in replacements for the Tripath modules. I have used them in the past to repair some Audio Research 300.2 amplifiers that used them and they operate even better then the older modules.

I would really like to track down which resistors are different If anyone has a 2500 board and could take some photo's, please PM me. I would like to offer these up for sale and be able to modify them to the 2500 version if someone needed that specific version.

anyone have any info??

Hi All, I see that it was being discussed in 2003 and wondered if any of those 44 owners are around and still had a copy or if any current members have a copy?

Is it true that Quad numbered channel components either odd or even?

Thanks

OK, bear with me here, this crazy idea has been haunting me for a couple of years. I keep thinking it would be such a fun project to bring to Burning Amp.

Here's the idea: use a pot (one with a thick aluminum bottom disc) as a heat sink for an Aleph amp (the forthcoming Aleph J boards look square-ish enough?). Mount the semis without penetrating into the interior of the pot. And fill the pot with water. Mount the transformer/power supply in a circular enclosure underneath, so the whole contraption looks kind of like a pot sitting on a camp stove.

Yes, I know it's crazy. Yes, I know having water close to electricity is inherently unsafe. Let's just think about this theoretically for a minute, shall we?

Is it even thermally feasible? Does anyone know what the dissipation would be for an aluminum pot with a half gallon of water in it?

Anyone has made a PCB for First Watt iv?

Hello all !
I bought this amplifier board from Connex. Need help to understand the left and right channel -/+/ gnd wiring from input on the board to the
right and left on the teminals. Anyone out there to help a newbee?

Hi Looking for 2 x LTC1968 if anyone has it would be much appreciated.

Thanks

I have a pair of lightly used SB acoustics MR16P-8 for sale. They look in perfect condition to me.
Located in the UK.

Please make me an offer!

Hello,
Having a problem with my Pioneer SX-1250.
I replaced the 4 filter caps, recapped the power, protect, stabilizer and amp PCBs. Upon start up, voltages at VR1 and VR2 are stable (65v) on the stabilizer and voltages are stabile on one of the amp boards VR1 (0 Volts) and VR2 (I set to 75mV) BUT on the other amp board both voltages are unstable and vary widely. Any ides as to what the probable cause is?
Thanks.

I am seeing ads even though I'm a paying member that requested no adds. My contribution level allowed that option.

Hi to all..

I make this shematic and in theory (If I didnt miss something) it shuld be work and give it high power with 4 x IRFP450 and 4 x EI33 from ATX power supplay without re-winding and changing anything.

Working freq. is 100KHz (7.5K + 1nF) and two of this gate drivers IR2153 are connected for Full Bridge in PSM (phase shifting modulation) which provide output voltage adjustment with trim pot. (Setting up angle of pahse shifting change voltage of primary winding of 0V to 320V).

On 100KHz for full bridge EI33 can deliver 400W and need 40 turns on primary side because of Full Bridge tipology (double number of turns on primary). For bigger power we can use two EI33 transfomers like one big transformer (each primary in series and secondaries too with GND central tap) but each transformer need only half of number of turns.

Than we can make from the outside (without transformer opening) two paralell windings of 20 turns on primary (original serial winding 20t+20t reconecting in central tap) and connect with two parallel windigs on second transformer to make serial conection of two paralel primary windings.

Two of this gropu of transformers are conected now in parallel for double-doubled power (4 x 300W = 1200W), with separated two caps of 2.2uF for output of the transformers. (This caps are here becase EI33 dont have an air gap)

Because this is SMPS without feedback, i can play with transformers like that. For protection I will make overvoltage protection and overcurrent protection with current sens transformer on primary side, but that is for future.

What do you think, can it work and be powerfull?

Thanks and regards, Nikola

I'm going to perform the full set of Horizontal and Vertical measurements needed by Vituixcad for designing a crossover for a TPL-150H + AE TD12M (will use a Monacor DSM-48Lan for Active crossover), following the process described here.

I have a Cross Spectrum Labs UMIK-1 bought in 2017, which i has going to use for this, but given that the Vituixcad advises against it, i was considering buying a cheap Behringer ecm8000, and use the UMIK-1 to create a calibration file to it.

I contacted CLS to inquire about how accurate the UMIK-1 should be given it was bought 4/5 years ago, to which they respond:

Over four years, there will probably be a slight drift in the response, but assuming the mic has been properly handled & stored, the drift shouldn’t be more than 1 decibel or so ...

Click to expand...

So i've been researching and trying to understand what to do, and this basically sumarizes my options:

1 - Accept that 1db is not relevant, buy the ecm8000, and use the UMIK-1 to calibrate it: Total cost = 40€,
2 - Buy the ecm8000, and send it to hifi-selbstbau, they offer a calibration service for both 0º and 90º, available here: Total cost = 40€ (ecm8000) + 40€ calibration + 30€ shipping (both ways) = 120€,
3 - Buy a EMX-7150 from isemcon, available here for 250€: Total cost = 250€ +15€ (shipping) = 265€,
4 - Sell the UMIK-1 (should be able to get at least 50€), and get a new UMIK-1 from CSL (and use to calibrate the ecm8000), it has a total cost of 160€ imported from the USA: Total cost = 160€ - 50€ + 40€ (ecm8000) = 150€.
5 - Calibrated UCM800 - Don't know how good the calibration is: Behringer ECM8000 calibrated

On 2), i don't know how accurate the calibration from hifi-selbstbau is, or how it compares to the CSL or the isemcon, but i assume it won't be as accurate.

On 3) Isecon now only calibrates their own microphones, and does it for a 38€ cost.

Basically i think i only have two options, either accept the potential drift from the UMIK-1 and just buy the ecm8000, or if i go with a calibrated option, it makes sense to invest in the long term, get the EMX-7150 and calibrate it every few years.

DcibeL said:

If you are that worried ...
How much do you care about "up to" 1dB of difference ...

Click to expand...

That's what i'm trying to understand 🙂
How much impact does a non perfect microphone has in the final result? Maybe it doesn't matter, maybe it does, i simply don't have the experience to know it.

I would like to know opinnions about.

I think it is too much complex....i have suspections that may not sound fine because of double simetrical into the input.... the ones i have tried into my house, made this way, have not sounded fine to my ears.

What do you think.

Files are big.....but high resolution.

http://svetelektro.com/upload/Titan_2000.rar

regards,

Carlos

hi all,
in the web i've found this software....seems very intresting, it calculates also double bass reflex, but language is japanese.
Speaker Editor 4.32

there is an english version ?

thank you

Has anyone come across a service manual for a Nikko STA-8080 (or STA-7070, STA-9090 since they may be similar enough to troubleshoot a problem on the main amp)? The one that I downloaded from HiFIEngine is so pixilated at a legible zoom setting that I cannot read any component values or voltages. Thanks for any help.

Brian

Hi all , I am looking the schematic or the service manual of the perpetuum-ebner hsv 60T integrated transistor amplifier. I need only the schematic only from the output (power) stage. I have one of this rare unit in very good condition, and one channel can not set the dc voltage correctly. I changed all transistors and elec caps, but the problem remains. So I have to look deeper. If anyone can help with a schematic it will be perfect.
Regards

I have not built much in the way of audio for a few years, now, but got an itch to lately. I already own enough speakers and amps for my needs, so cannot justify an all-out build. As a flip-side to my more standard speaker design/building efforts, I have stashed away some less orthodox designs such as Karlsons, RJ and Nagaoka-inspired enclosures.

I have this simplified and shortened version of the Karlson SK8 I called the mini-SK8 or mSK8. I designed it hoping it might do well with pro drivers such as the B&C 8PE21 or 8CX21, with some power above 100Hz. I do not have these drivers or other suitable. What I do have is a pair of Faital pro 6FE100, although I measured their T/S parameters to differ from factory specs, namely lower Cms, higher Fs and Qts. I decided to go with these despite not being usual suspects for Karlson.

There exits a high-aspect 6" Karlson dubbed the HAK6.5, but wanted something simpler and a bit smaller, so I designed the below, calling it Tall K6, or TK6 for short.



I wanted to keep the SK8's 20" internal height, but reduce the rear to front chamber volume ratio. I used my adapted BP6 model to design to my 6FE100's parameters. It's also a good occasion to test said model, simple as it is.

BB-ply price having gone way up, I opted to build the outer shell from MDF and used leftover BB-ply for the wings and internal panels. I've also built only one unit, as this is somewhat experimental and I like a single Karlson playing mono as well.









The wings and back panel are unbraced as of yet, but I'll get around to doing so. I have taken a few measurements, which I will post shortly.

Hello guys. i'm looking for a aforable amplifier with spidf input.

max budget- 120€

i found this 2 guys. can someone tell me wich could be better?

pretty same "chinese specs" these are the differnces.


AIYIMA D05
Chips set: CM6642, TAS5508, TAS5352A, QCC3008, CS8422, WM8782
SNR(Singal noise rate): ≥105dB
output power: 120W+120W 4Ω


AIYIMA D03
Chipset:CS8422+QCC3034+SA9123I+TAS5548+TAS5624+PCM1808+DRV603
Signal to noise ratio: 93db
Output power: 150W*2 4Ω

all we know that these outpout power are not "real". could be te SNR also "chinese SNR"? could be the D05 better?

also it says this on the specs. i don't know what really means ¬¬




thanks.

This is an audiophile/videophile Coris Linear Power Supply upgrade for Oppo 203 & 205.

Brand new, never used. I purchased it back this spring and ended up going another direction with a Panasonic 9000 and never installed it in my Oppo 203.

Super simple plug and play power supply upgrade. Coris has a number of youtube vids showing step by step replacement. No permanent changes made to player.

I paid $430. Looking for $400 net to me, plus shipping at cost.

Photos images on my parallel post over at Audiocircle trading post, accessories.

Thx
Kenreau

good day everyone! I have this amplifier that has damaged switching! mosfets have the code H1 and the power supply diodes have the code S1 and S2! do you know what it corresponds to or can you give me a site where you can check? Thank you and good job to everybody !! Sorry for my english

Wanting to order an Allo Kali but Audiophonics now have a 160eur order minimum for the UK. Because Brexit.

Kali is about 75eur so there is some short fall to make up but if anyone in thr UK was wanting anything from our French friends then maybe an opportunity.

Cheers

FYI,

While viewing the mobile site on Samsung S8. When I click on "load more", I get the error.

Hello together,

I`ve get my hands on some used Dynaudio P31. They are nearly 40 years old. The foam surrounds are broken and need a make over.
I disassemled the woofers and start cleaning them.
Get some progress,
But now some question pop up.

At the edge of the paper membrane there is some yellow foil.
Do someone know, is this foil part of the Membrane or part of the old foam surround?

If its part of the old surround, i have to remove it right down to the paper.
Do someone have a tip how to this properly?
Till now i have applied some alcohol to the old surrounds and scratch the leftovers away.
If there is a better way suggestions are welcome.

Greets Alex

Looking for ideas (or an intervention) on how I could cobble together a basic balanced signal chain for as little money as possible since this is primarily an experiment to see if this can solve my RFI issues.. I'm thinking along the lines of hacking balanced output from one of my DACs and adding balanced input to an existing amp. The main hole would be what to use in place of the preamp that has remote volume control. I don't have any other sources than S/PDIF and I don't think I need the gain of a preamp.

Apple4K TV -> HDMI switch -> S/PDIF -> DAC -> Preamp -> Amp -> Asathor. My ICs are Belden 1694A from Blue Jeans Cable.

In my living room, I've been fighting RFI issues from 94.9 FM for several years since moving to the city where I can see three transmission towers from my couch about 1.5km away on the next hill. From my bedroom, I can see another three 5.5km away! I don't have these issues in my basement (audio only, no HDMI).

I jumped through a bunch of of hoops over the years with different equipment combinations (mostly DIY), ferrites, LC filters on inputs, cable management, etc with modest improvement. My commercial gear doesn't perform any better than my DIY gear.

Relatively recently I though I solved it when I found that RFI went through the roof when my amp's ICs and speaker cables where in contact with one another. But over time it seems come back and I start over and I seem to be getting inconsistent results. For exampl, today I did lots of cable tidying and had no RFI with the preamp inputs shorted and then it was back 15 minutes later.

My current DAC is a Soekris 1021, great DAC, really liked its performance, but it unfortunately died after an ESD incident.

I'm searching for another 1021 but are there alternatives that I should consider ?- other than Soekris

Budget is tight

Cheers !

👍

Hey guys any idea what Driver this is being used in this Frugal Horn XL unit?

I asked this when we first migrated but I put it here aswell.
I would like to see nationality flags back for peoples locations.
Will we see these make a return?

On the old site I could bookmark specific forums on my phone, put them onto the Home Screen, and then just click on them to go straight to the forum eg swap meet, tubes etc. Now it just goes to default home page. Is there a way of doing this?
Thanks

Signatures are not displayed when I am browsing the forum on my mobile phone, while they are displayed correctly on my computer. Is this a bug or a feature? (I'd say it is a bug, as information is not displayed as intended by the users.)

I have decided it's time to stop looking and jump in and build a line array,
I can just about fit 24 TC9's between floor and ceiling with only 2" spare.

My question is, what are the pros and cons of a straight array v curved array (somewhat like below) focused on my listening distance about 4/5m away from speakers?
Equalization will be done by miniDSP.



Any thoughts or ideas from anyone with experience of this type of speaker would be appreciated.

Steve

Hi!

Is there an ETA (and maybe a waitlist) for when the upcoming crossover boards/kits will be available for order in the store?

Thanks,
Olen

I'm currently planning to make a pair of 2-way open baffle speakers;-fullrange and woofer.
The woofer (Eminence Alpha 15A), will be powered by a 45 watt Quad Vena II solid state amp, and the fullrange (Coral Flat 8 II) by a 2A3 SET-tube amp.
The fullrange is 101dB and the Eminence is 97dB so the fullrange will need to be brought down to the same level as the Eminence.
Only problem is the 2A3 amp is only 3 watts or so, but I've been thinking this may work none the less.
So,-the total system will have a sound pressure level of 97 dB at 1 watt/1 meter distance (3 feet).
At 2 watts the level will be 100 dB at the same distance.
6 feet away we're talking 94 dB, and at 12 feet (listening position) the sound level will be 91 dB, and take note that the 2A3 amp will still have some juice leftover.
91 dB is considerably louder than a freight train at 100 feet distance (80dB) so it will hopefully be loud enough.
My listening room is roughly 15 by 15 feet, so not a concert hall.
I will mostly use the system for TV sound and for listening to music now and then,-not heavy rock mind you.
As I see it the little 2A3 amp may be sufficient to power those Coral fullrange speakers above 200 Hz or so, but I may be out on a limb here so please feel free to correct me if I'm wrong.

I just aquired a pair of TAD 4001 drivers, and have recently been involved in some threads discussing a possible setup. Yesterday, i stumbled across a page that really caught my attention.. Sierra Brooks manufactures a line of mahogany tractrix horns, very good looking indeed, and very expensive ofcourse, but what I found especially interresting was the DIY-projects section of the site. They show a number of setups using the TAD 4001 driver, but each and every one of them utilizes one of their largest horns, a 140hz tractrix horn as shown below (the big one, mated with two Onken tweeters):

So this makes me think.. as I'm using affordable diaphragms from Radian (aluminium) much more rigid than the fragile and expensive beryllium ones, I am not too afraid of blowing them although I would rather not... Radian's datasheet on the phragms indicates a 600Hz XO with 18dB/oct slope, but says nothing about power handling at this XO config...

My question is if these drivers are usable below 600Hz, and down to what point, assuming a maximum power handling of 1 watt only, and active 24dB/oct XO slopes? These japanese guys don't use 140Hz tractrix horns just for the fun of it, do they?

A neat "modular elctronics lab system for hobbyists".

https://gitlab.com/Chrismettal/EleLab_v2#elelab_v2
Kind regards,
Drew

Hi All.

The foam surrounds finally arrived for my SEAS Woofer repair work.

The old surrounds appear have hardened a little and appear breached in one or two places.
The cone material appears to be paper.

I really would prefer to keep them as original as possible.

Is there:

1. A preparation which, when applied can make the old surround more flexible? and

2. A glue which can be used to patch any breaches in the surround?

Many thanks

Cliff

Hi DIYers, I need some amplifier troubleshooting help.

I have a monitor audio FB-210 subwoofer that doesn't seem to pass input signals.

With it all connected with the cables I've been using with my current sub, the sub recognizes and wakes up to a signal(led changes from red to green when signal is delivered).

It makes a little thump when powered on or off with the switch. I get a very very soft thump when the volume knob is all the way up and turned back and forth a bit. That Is louder when the frequency cutoff is all the way to the high side. Also a super soft hum when the input rca has only the center pin inserted part way.

When rca is plugged in and I touch the other side of the cable , I get no sound unlike my old sub.

I have +/- ~65V on the output transistors and some speaker thump when I touched some of the transistor pins to take measurements.

It has 2 + and 2 - output transistors and 2 smaller balance transistors plus 1 tiny Darlington transistor between them. I removed all and they measured fine outside the circuit.(except I cant measure the Darlington really)

There are 2 driver transistors, one was removed and measured fine.

I got weird measurements for all transistors in circuit but I assume that is heavily impacted by the other components on the board. Some of transistor measurements on diode setting took 3-5 seconds to ramp up to OL from ~1.5V when in circuit but were fine when removed from circuit.

I do not have schematics for the fb210(cant fine them) but do have them for the fb212, which is the bigger brother.

I have not removed the separate input/filter board because its glued to a foam surround.

There is a 6 pin connector between the input and amp boards. The 212 spec says the pins are SG, GND, +15V, GND, -15V, CONT. I measured good grounds and +/-12V on power pins(probably right but I dont have the fb210 spec) Also 10V on CONT and small mV on SG but I may have those 2 backwards.

I'm sure this isnt the best way to report all this ... hopefully someone can help tell me what I need to look at.

I'm looking for a LTSpice simulation on this. There are some around, but the use Triode mode, not Ultra Linear and mostly different tubes, Like KT66.

I want to start with the original design.

Any help ist welcome.

ThanX Winnie.

Hi,

I would like to know your opinion on this.
I will be measuring an empty room I've built : 8x6x4 meters with an angle roof before I start working on treatment and I would like to know what do you think would be the best speaker to use/excite the room

Either :
- JBL 305P with 10" sub or any other brand really
or
- Small PA system like the dB Technologies ES602 (two sets)

What would be best and most usable ?
I would be placing the speakers where I ill have the final monitors once the room is treated.

Thank you

Manu

I took my Nakamichi DR1 out of hibernation of 20 years (bought new in 1994). I replaced the drive belts but one of the channels has no output. When I switched between Type I, II or IV positions there was an intermittent sound on the dead channel, but it would cut out again within a split second. I hooked the output to a scope and found that the dead channel has a large DC offset that can go from -4V (Type I position) to +3 to +4.5V (Type II or IV position). When the DC offset switched between negative to positive while switching between Type I or II position the sound would come on for a short time until the DC offset gets high again. It is like the DC offset saturated the amp. When I keep it playing for some time, the DC offset would sometimes come down low enough and the channel would play (but I can still see 1-2V DC offset).

I found the schematic from the internet, and was able to isolate the problem to be in the playback amp PCB. I replaced all 6 electrolytic caps and in fact found a bad smelly one from the dead channel (C206 in schematic). I thought that would fix it but the dead channel is still dead. The DC offset is still there. I measured every point in the schematic and compared the measurements on both channels using a scope (while playing music), so I was able to see the signal plus DC offset. Both channels measured very closely except the output from the bad channel has a DC offset after the capacitors on the output side. The output is AC coupled so I couldn't figure out where the DC offset came from. Everything to the right of the dotted line in the schematic matched very closely between the channels but the left side has a DC offset in the bad channel.

Anyone has an idea what is going on?
Thanks.

Hi. Nice to be here.

I'm a budget audiophile in NZ. The land were everything hifi is megabucks, and hobbits may or may not be real?

I'm no expert, but maybe i can pick your brains on a speaker upgrade here and there.

Thanks in advance.

Skyfire

The following circuit is a copy of an LM555 (equiv NE555) based relay delay circuit I designed around 20 years or more ago for muting the output of a preamp. The design goals were reliable operation and the ability for the circuit to give the full mute period if the power supply was cycled quickly on and off. Some recent threads on diyAudio have enquired about such circuits.

The design offered here is done so as more of a 'cookbook' type of design that can be altered and changed to suit individual requirements rather than a fully documented construction project.

Practical points:

1/ Ideally the circuit should be fed from a small auxiliary supply of limited 'reserve' capacity. This means a supply of minimal reservoir capacitor size which ensures that the relay drops out very smartly on power off. A single half wave rectifier and smallish cap (perhaps just 220uF) is the kind of thing that would work well. Ensure the ripple rating of the cap is not exceeded. A little series resistance added to the supply works wonders in dramatically reducing peak ripple currents.

2/ The delay can be altered by means of the time constant of R3 and C4. You should ensure that the combination chosen is suitable. For example it is no good using a 10 Meg resistor and a relatively large and leaky electrolytic cap.

3/ The design has not been tested with either the low power or CMOS versions of the chip. In practice the relatively high draw of the original LM555 can be useful in ensuring the rail powering the device collapses quickly should the power be cycled on/off during the initial period the delay is operating.

4/ The LED indication at the right is something I didn't build into the original, however it could be useful for some. The series connected LED + resistor network seems the simplest method of achieving this and uses the fact that the 555 output switches between supply and ground thus effectively shorting out one or other of the indicators. The series resistors are scaled to suit your LED's.

5/ The original 555 has a wide operating supply range of 5 to 16 volts and a source/sink ability of up to 200ma.

6/ It is very important to decouple the NE555 very close to the power pins in order to avoid false triggering. My favourite approach is to neatly solder a small high quality 10uF cap directly across the pins.

The following images show the circuit diagram, the relay current vs supply voltage in normal operation (the power is on for 1 minute) and finally the behaviour of the circuit in response to rapid cycling of the supply. This is where using a power supply with a small time constant is advantageous.

Edit history...

.asc file updated to enable it to run using default LTspice models.

Waynes BA2018 and Biamp 6-24 crossover

Just having purchased both of these I have the following questions.

With Waynes BA2018 as a preamp I seem to have made a mess of the surface mounted Jfets. They are out of stock at Mouser and Digikey. Does DIY have a stock so I can attempt to replace them or am I relegated to getting the whole kit to try again? I purchased a new soldering iron for the job and I expect I will need to start again to get this happening. I propose gluing the little blighters with a small dab of contact before a careful soldering under magnification. Any help gratefully acknowledged.

With the crossover I have read countless pages searching for the BOM. I know it must be somewhere but can't locate it . Do I have to just read the board? Nelson also said there was a build thread by 6L6. It's certainly not listed anywhere I can see.
I have also not been able to understand the way we work out what capacitor values are needed for a certain frequency. Sorry I am right down there before most of you ever heard the word electron. So I'm wanting to put frequencies up to 300Hertz through my transmission lines and everything else goes up. I can't understand the graphs that keep making everyone so happy. Just failed that intelligence test.
Maybe one of you kind boffins could help me to work this out using that lovely looking crossover board . Also those big side caps are a total mystery as to their value.
In my defense I built an Aleph J that has been flawless for a few years and am slowly getting the stuff together for a second one. My soldering is not attrocious and I can get things right with a small amount of assistance.
Cheers.
Dan

Hi,

most of us might know the »Deacy« amplifier that John Deacon of Queen had built from an old radio and which is responsible for Brian May's signature guitar sound. It's main features are the germanium transistors used in any stage and it's transformer coupled output section. Even phase inversion was done with a transformer.

As there are many Ge transistors in my stashes, I have the idea to design an amplifier with these features. I think the math can easily be done for the output transformer, but I'm completely lost with the PI tranny. How do I calculate the power transistors' drive power demands and the winding ratio?

Best regards!

I am looking arround to RC volume control kits, at best include envelope (enclosure) and RC transmitter hand set unit (motor pot or dig. controlled). Please note: Not digital attenuator, but digital controlled attenuator.
On ebay there are a wide range of bidders without envelope and only partly solutions (either only RC transmitter/receiver unit or only volume control unit with SPI controlled pins), but I want to have a completly kit like Vellemann K8022.
At follow this no longer available Vellemann Kit and some other examples:

A: RC Motor Analog-Potis
1) Velleman K8022 PASSIV Preamp with remote control
K8022 Passiver Vorverstärker mit RF-Fernbedienung im Sly-electronic Shop Berlin
http://www.sly.de/bbilder/k8022.jpg
Fernsteuersender Handsender 2 Kanal VM130T - Lüdeke Elekronic Elektronikhandel
http_www_velleman.eu/distributor/products/view/?id=345984
associated RC transmitter:
http_www_velleman.eu/distributor/products/view/?id=374092
2) RCLL, Remote Controlled Line Level Volume Control
Audioplex RCLL-1 Remote Controlled Line Level VC
http://www.audioplex.com/RCLL1 revised.pdf
3) MK161 - IR 2 Channel Remote Receiver Kit
MK161 - IR 2 Channel Remote Receiver Kit - Ramsey Electronics
4) MV-04 motorize remote volume control
DIYCLUB
5) Remote control audio kit
Dantimax - Remote control audio kits

B. Remote Controlled Switched Resistors by Relay
1) The remote control paratactic volume control
http://www.diyaudio.com/forums/solid-state/56009-remote-control-paratactic-volume-control.html
2) Audio Volume Relay Attenuator with IR Control
Audio Volume Relay Attenuator with IR Control
3) Remote volume control board, using relay - Halcro also use relay on their DA10 pre amp
DIYCLUB
4) VolControl, Volume/attenuator control board
Dantimax (elektronik) - Control_boards
5) TentLabs Volume control
Volume control
more kits:
DIYCLUB

C) Semiconductor switches (C-MOS series)
1) Remote Controlled Stepped Attenuator
Welborne Labs Remote Controlled Attenuator
2) RC-16 Remote Volume Control (looks like that one from Cyrus III and Cyrus IIIi / Cyrus 3i)
http://www.oxmoor.com/files/cut sheets/DCA-2 RC-16 cut sheet.pdf
RC-16 Remote Volume Control - Oxmoor Professional Audio Products

And here several IC solutions for volume control application:
Digital Potentiometer
Digital Potentiometers and Capacitors (ISL22317)
Digital Volume Control
Volume Control - Volume Controls (CS3318)
2-Channel 78 dB Audio Attenuator
LM1972 - Micro-Pot 2-Channel 78 dB Audio Attenuator with Mute
Stereo Audio Volume Control (PGA2310-2311-2320-4311)
Audio - Volume Control - PGA2310 - TI.com
Electronic Audio Attenuator dc controlled (MC3340)
http://www.datasheetcatalog.org/datasheet/motorola/MC3340.pdf
MAS9116 - Stereo Digital Volume Control
MAS9116 pdf, MAS9116 description, MAS9116 datasheets, MAS9116 view ::: ALLDATASHEET :::
Dual-Channel Digital Volume Control with CMOS switch 4066
http://www.electronicsforu.com/efylinux/circuit/feb2003/aug99_dualchannel.pdf
Digital controlled stereo audio processor TDA7313 (ST)
http://ampslab.com/PDF/tda7313.pdf
http://www.st.com/stonline/stappl/p...type=4&tname=TL_DATASHEET_TREE_X_DOC&latest=N
Maxim DS8102 - the new volume control chip
http://datasheets.maxim-ic.com/en/ds/DS1802.pdf
DS8102 Dual Delta-Sigma Modulator and Encoder - Overview
DIY: high end DAC and digital volume control | Flickr - Photo Sharing!
TDA7439 (Linn Kolektor) THREE BANDS DIGITALLY CONTROLLED AUDIO PROCESSOR (ST)
http://www.datasheetcatalog.org/datasheet/stmicroelectronics/4291.pdf

In the attachement various CMOS solution schematics.

I want to have a good overview about completly kits like the no longer available Vellemann K8022.

Thank you for additional proposals.

(copyrighted images removed by moderators)