Hi All,

Most should know what this stuff from the Sony TC500/TC500a R2R is. I picked one up to cannibalize the power supply.

The surrounds on the Coral FE103A variants feel pretty good--not too stiff. See minor damage to one dustcap. I don't think that'll make a difference. These are nicer than my personal set, but I'm too lazy to swap them out.

The Tamradio/Tamura-ish transformers look fine too. These used 6AQ5 outputs and are great for EL84 or 6V6 SE projects like the RH84. Interesting possibilities with the recording head tap.

$75 for the speakers, $50 for the OPTs. $15 to ship to CONUS for either the speakers or OPTS. Free shipping to CONUS if you want it all. Others ask for quotes.

Paul

I'm looking for an amplifier project with 18c51 tube.

Hi Folks,

i was wandering about (mostly) cheap pa coax drivers, that they have the same sd in their manuals and test as a driver would have without a small horn embedded in coil.
So if one for instance would take an emi beta 10 or 12 (and the 8 inch too) they have like these small horns inside their coil for the hf, but should this not be went in the calcultion of the overall sd for the driver as well...? Like ok a twelve inch speaker has an sd of roundabout 500 and whatever square cm...sorry folks i'am metric 😀, and you have to deduct like whatever the horn would be?

Ok one could assume that the dustcab would count into the overall area as well, but in the case of these drivers the dustcab is more like a stiff mosquito net which lets air flow through, so maybe not countable?

Would be glad if someone can elaborate this, and why most manufactors still put it the way they do?!

Greets Swany

Can someone here tell me how to change de emphasis on a Dyna FM3? Oddly, or not, I'm now not sure, the de emphasis on my Tandberg 3001A sounds like it would in the EU when set to 75uS. It's definitely overly bright so I switch it to 50uS. It now sounds great. OTOH, the Dyna FM3, which functions as it should, sounds like it needs higher de emphasis. Does anyone know what it actually is?
TIA

SOLD: MSB Multiple Volume Control MVC-1 (Qty 2)

SOLD: Qty 2 MSB Multiple Volume Control MVC-1. Passive 8-channel pre-amp with remote control. One master, one slave for a total of 16 channels. These are from the days I was using active cross-overs on all three front channels of my home theater. I had these between the DSP and amplifiers.

Sorry the slave cannot be converted to a stand-alone unit without a new microchip which I don't have. Perhaps you could clone off of the master chip or contact MSB. Otherwise the two units are linked together with a network cable. Very high quality case and internal components.

Asking $350 OBO for the pair plus shipping and 3% paypal fee. Local pickup possible. I will not separate.

Hey everyone!
So I was looking around for some cool tubes and this baby caught my attention.
The seller doesn't know much about the tube and stuff and he has provided only 2 images. He says in the description that it's off a military thingy and it works on the HV side.
Just by looking at the pics, I can see the letters "ТМИ-9" which is basically "TMI-9". I can't really see the other number(s) and was wondering if people who are into Russian tubes know anything about this.

Obviously, searching for "TМИ-92", "ТМИ-90" or "ТИИ-98" doesn't yield any results.

The images have been attached below.

I am looking for opinions regarding the SB Acoustics MR16P 6 inch midrange driver and the ScanSpeak 18M-4631T 6.5 inch midrange driver.

I am looking for both subjective evaluations and objective comparisons (beyond what can be obviously determined be examinin the spec sheets...)

I intend to use these drivers from 200 Hz to 1.6 kHz in an active 3 way.

The SS 18M is about $220 while the SB MR16 is about $150. I want to understand if the SS 18M offers performance which would have value in my application.

I've designed a board to evaluate the Lm3886 and Lm2876's in stock and I need your opinion on how it looks.

I broke the PCB out of its cheap plastic case today, and was wondering why there's a capacitor between the + and - of each channel.

Any ideas?

Thanks!

Aurum Cantus APR 3.0’s
Excellent condition!
Rarely used
They were $600 new

$250 for the pair seems quite fair 🙂

For those of implementing a multi-way active XO with EQ APO and Peace, how are you mapping the Peace channels/speakers to your DAC channels?


There's a "select a device for the equalizer" pull down menu in Peace where I can select one of the four stereo outputs of my DAC but I can only choose one for all the channels. If I select another output, change to another channel, the output for that channel has also changed.


I'm using (or trying to) use a Presonus VSL1818 as my 2X8 processor. Is it the audio interface driver that is the issue or ?

Is there a specification for the 8 x M3 holes in 10mm front panel for 5U Deluxe chassis?
If a drawing exists that can be printed and used as template for drilling exact holes in a mounting plate that would be helpful. A quick look into DiyAudio Store only revealed the specification for the holes in the heatsinks?

There is something i find rather confusing, and that the delay x-over orders create. I always hear that using a 1st order will result in no phase change. However 4th order will end up with a 360 degree phase change. 3rd is 270 degree change and 2nd order 180 degrees. This leads me to believe that first order actually has a 90 degree phase change but because it's one low-pass and one high pass, they cancel each others time differences and therefore is phase coherent. This is probably true for a 2 way, but what about a 3 way were the midrange is using 1st order on both the high- and low-pass side? Also, does that mean that if using the same order of low- and high-pass the lead and delay will cancel eachother? And is this delay just phase related or time delayed as well? Because if so, as long as you have the crossover point low enough, the difference in orders between low and high pass can make the drivers time coherent even when the acoustic centres have different distances to the ear.

Don't know if I'm talking rubbish, but if you know, or know about any good source material I'd appreciate it

Would anyone help me with some design rules to apply a baxandall tone stack in the feedback loop of a headphones amp with a gain of 10...20x?Both inverted and noinverted popology would be considered.

This amp has me stumped. When I apply power and remote. Nothing happens. Also it appears to have 2 tl594 chips which is something I've never seen before.

Using op amps, in the usual inverting configuration and the non inverting configuration.
What is important to achieve a best gain stability.
I am thinking of:
The resistors with low temperature coefficient.
Thermal matching of resistors.
What else, should I care ?

The gain value does not need high accuracy, there will be calibration to take care of this aspect.
The important thing is the need for a perfectly stable value.

Ok...I'm old enough to remember techs using Rubylith film to layout circuit boards.
Anyone else?
Wikpedia Rubylith if you don't know what I'm talking about.
If you look at solid state gear from the 60s through the 70s you'll notice the PCB traces are of variable width, and most evident, are not necessarily orthogonal. Often the junction of three or more components will be implemented with a large fill area they all emanate from. Corners are round or any shape you can dream of.
Laying out with Rubylith required developing skills with a razor knife. It's nothing you could do successfully right out of the gate. You'd have to waist some material before you got good at it, and the material was not cheap. Sometimes a special table that guided a razor knife or parallel razor knives was used. I never did it personally but i witnessed guys doing it who are likely 70 years or older by now.
Anyway, I have a Peavey guitar amp, the Session 400, from 1975 that I still use frequently to this day because I've never found anything that beats it sonic-ally. The layout was obviously done with Rubylith. It's totally discrete, The pre-amp is single supply using many coupling caps between stages etc. I have simulated the circuit and have concluded there are some interesting design twists you don't find in other circuits, like a "loudness" affect and an interesting and effective parametric mid control. The power section is 200 watts! - done with all NPN.
I wonder now if the trace routing style makes any impact on the sonic qualities.
Anyone with an opinion on that?
Also, is there a modern software package that can do this style?
I imagine the graphic arts people have something but likely not optimized for layout. - probably lacks net/schematic coordination.

I recently heard a passage of piano where you could hear the mechanical elements of the piano as the musician played.....pedals being pressed and the hammers actuating ...can't remember what it was but it was a good genre of music to 'show off ones system...it sounded really good.

Any links or heads up of anything that sounds similar.?

I am not a speaker designer or engineer, just a curious designer who's been obsessed with horns for some time.

I've always been amazed there aren't many options when it comes to horn speakers - especially conical horn speakers. The only ones I can find from the likes of OMA or Avantgarde are tens of thousands of dollars.

I want to build something based around a JBL 2446 in a conical horn and a faital pro 12 or 15 woofer. I mocked up a really rough design of a speaker design I've struggled to find from an aesthetic point of view that I find pleasing. Of course this could be created in many different finishes.



Any takers? 🙂

(This is of course just for fun)

Hello everyone
It’s the first time am posting in this forum, in this project I’ve tried to push the amp to the extreme without losing stability, with the help of the books of Mr. Douglas Self and Mr. Bob Cordell I think I’ve achieved an amp with a Phase Margin of 110° and a Slew Rate of about 120V/us, with a very simple 3 stage amp. Till now it’s just simulation, am using Multisim, and the results looks very promising.
Any suggestions is very welcome, hope to find you all in good health and stay safe
Best regards KADER

For an MM phono preamp, is a SINAD of over 100dB even theoretically possible using modern state of the art OP amps and circuitry?

Ok how can I use 1400 uf 350 VDC computer grade electrolytic capacitor(s) in a tube amp power supply. The company my son works for installs server farms and they have a case of NOS never used 1400 uf 350 VDC computer power supply capacitors heading for the dumpster. I told him to grab it for me. I was thinking as part of a brute force power supply for a preamp or amp running on under 300 volts. They are Sprague capacitors so not Chinese crap.

For sale a pair of F6 modules built on boards supplied by palstanturhin.

Well matched genuine Toshiba jfets supplied by spencer with matched mosfets from ha. The boards can also be altered to run with a diamond buffer front end instead of the jfets.
https://www.diyaudio.com/forums/pas...forums/pass-labs/216616-f6-amplifier-609.html. See post 6084.

I would like £150 for these to include UK postage; elsewhere at cost.

Hi good people! I want to install Tang Band W3-871SC in my car on top of the dashboard. The enclosure therefore cant be too big, so I wonder if attaching a tube to the enclosure will work for raising the volume. In my case I would hide the tube in the dashboard. At home such a tube could be hidden behind furniture. For example if closed box I would maybe make an enclosure with 0,5 liter enclosure and to this attach a tube with 1 liter internal volume. Would this equal an ordinary 1,5 litre kabinet?

Cheers!

Hi guys, I’m looking for some horns for a 2nd room. Which is better ?

Guys,

i have an issue and not quite sure what is causing it, but lets see if somebody has come across it.

Working with no issues using CSR8645 bluetooth amplifier board. Noticed that youtube has tried to mute the sound a little on a few songs so please disregard the poor sound.

Designs by 3rutu5 - DIY Boozetooth Speaker MK3 - YouTube

I've currently tried boards from various sources and get the same issue on all but one board.

CSR8645 (have 3 of them, one works flawlessly in above video)
CSR8645 Bluetooth V4.0 Amplifier Board Module APTX 2*5W for DIY Bluetooth Sound Box

and

CSR8645 (have 2 of them)
Bluetooth 4.0 CSR8645 Amplifier Board 5W+5W APT X Stereo Receiver Amp Module| | - AliExpress

QCC3003 Bluetooth Audio Receiver Module
QCC3003 Bluetooth Audio Receiver Module 5W+5W Power Amplifier Stereo Support Call BLE5.0

and

SANWU-HF69B-6W+6W (only have one)

SANWU(R) HF69B 6W+6W Dual Channel Stereo bluetooth Speaker Amplifier Board Power - US$7.46

I've been wanting to run a low powered bluetooth speaker setup just using a solidarity 18650 batter and a single speaker. All builds were based on AUKITS bose clone where a step up module was used to go from 3.7v to 5-6.5v which all boards can handle, and all but the SANWU were to have a 2000uf capacitor across the VGC, GND connection onto the board. The problem i'm encountering on all 4 boards is once the volume goes past 3 quarters volume or something with a bit of bass, the unit restarts and sometimes cannot reconnect. I dont know if the problem is specific to using these boards as the green one in the video does not experience this.

My thoughts is potentially it is due to the supply potentially, but as i removed the step up module for a test and changed it over with the DC\DC isolator i'm not quite sure. As it restarts, it could be under load and have a protection circuit or something on board, but i just dont know. The SANWU i havent had any luck with, but have seen a guy add some extra capacitors to the board, but i dont think it was for the same issue.

below somebody else's experience with the board.
https://www.instructables.com/id/DESIGN-AND-BUILD-YOUR-OWN-PORTABLE-BLUETOOTH-SPEAK/

I do realise i'm using no name chinese gear and it could come down to quality control or just the person i based it on could have got it from somebody else and have a slightly different board, but any advice for this noob would be greatly appreciated.

If i can finish my last project using one of these 4 boards successfully with an addition of a capacitor or something would be awesome.

Hi !

Anybody know what's the best class D IC model for hi-fi sound quality ?

Is it possible for an audiophile to go into class D without pain?

because I try only one time to compare LM3886 high quality parts amplifier VS TDA7498 and it was simply horrible !!! 🙁


thanks in advance 🙂

nicK

Hi,

I was asked by a friend why his Madisound BK-20 pair (fitted with TB W8-1808s instead of the Fostex) sounded so different from his previous speakers. Being a scientific fella, he wanted to know if the "different" was "better"... and despite the can of worms, I took a listen.

They sound bad. Off. Displeasing.

So much so that after an ad-hoc test of frequency response, I decided it was a great opportunity to play with the near-field scanner (that I never get to use...) since it is one of the few modules that can be used with a full system. (n.b. I've measured the drive in question free-field before and know it's, QC issues aside, not at fault)

I'm probably not supposed to post the actual graphs and measurements, so my 2-cent synopsis is that the response is very direction sensitive, a few degrees this way or that and the frequency response is all over the place. It's not just beaming, the problem is well down to 400Hz or less, and the best part is that it doesn't just scale with amplitude, it just morphs and changes in a wondrously non-linear way.

So I felt somewhat vindicated, but then wondered if there was anything to be done. I will admit I don't have a lot of back-loaded horn experience.

Is it simple or intractable or somewhere in between? (It did occur to me that swapping out 1808 for 1772 might help?)

Hey,


Could someone recommend tested board and verified seller for Chinese AK4493 DAC board.



Thanks in advance!

Evening All

I have recently closed on a new house that we will be moving into in the next week or so. I have been fortunate enough to have been designated an "office" space so I can move from the current dining room table setup into something a bit more suited for productivity. The challenge is that the room will also double as a "guest room" and triple as my "music room".

I have been looking at the space over the past couple of weeks and have some ideas but wanted to do some gut checking with the community before starting anything as the concept is a bit quirky.

I have a pair of mono-block SET amps based on the 2A3 which are good for about 6.5 amps per side, which I really enjoy and plan to use in the new room.

The room itself is 150" wide and 180" deep. There are a couple of extra alcoves (entryway, bathroom entrance) that increase the space slightly but I am ignoring those for now. The ceiling is 106" at the walls with a raised center.

The basic idea is to install a Murphy bed along the short (150") wall. Alongside the Murphy bed will be some built in cabinets to provide bedside table functionality and extra storage. Outside of that I plan to build some speakers, filling the space to the walls. The Murphy bed assembly is 90" tall.

I initially looked at doing a BIB or other large TL (even toyed with folding the TL over the top of the Murphy bed towards the center of the room, but it all got a bit complex). My major concern with the BIB approach was given how far apart the speakers are (around 135") and how close the drivers would be to the exterior walls, that I would not get a good result at my planned seating position, about 84" from the built in assembly.

Instead I decided to look at a full height sealed box with a large FR driver (thinking AN or Fane). Based on my estimations I could build a box with exterior dimensions of 14.25" wide by 16" deep by 90" tall. Only problem is that wouldn't fit a 15" driver and would still have the wide separation concern. So I considered whether I could angle the front baffle toward the center of the room.

The attached drawing shows speakers with the front baffle angled 30 degrees toward the listener. That makes the front baffle 16.5" wide which should be about enough to get a 15" driver on. In the drawing the black square is my estimate of my seating position beside my work desk (shown in green). The triangles coming out of the speakers show a 10 degree dispersion (in red) and a 30 degree dispersion (in yellow).

Without accounting for internal bracing or driver volume I calculated the internal box volume at about 350 liter (12.5 cubic ft). So good volume to handle even something like the AN Classic 15 Alnico.

But I have not seen anything online with similar geometry (narrow, tall sealed box) and with an angled front baffle, which leads me to believe there is probably a major reason why not.

If anyone has any ideas as to whether this will be a complete disaster, or has a good suggestion as to something else I could do with the space please let me know. Or if anyone has good experience with a BIB stuffed into a corner with a relatively close listening position please let me know. I am totally open to trying something different with this space, and while my diy skills are not the best I think I could have a go at most things. But I honestly have struggled to find much in the way of design ideas for a fully built in solution.

Thanks, Phil

Hello,

I am looking for the Encore DL2010a preamp's owners manual & schematics.

Encore was a Kansas City company founded by two Honeywell aerospace engineers in the late 1980's, Garic Laughlin and Michael Fessler. There were many prototype versions of the DL2010, all were state of the art at the time. This version was the best and last version that Daric Laughlin produced.

Best regards,

I have an SE D3a driver setup that seems to work pretty well in simulation. I need to swing the grid of the D3a to within .2 volts of 0 to clip the output tube though. Anybody have experience running them like that? Are grid current problems likely?

The basic setup is resistor loaded cathode biased 180V A-K @ 18mA with the heater biased up to +50

Thanks,
Marty

Hey Y'all how are you doing? Im only new on here and i have minimal knowledge on electronics but i have some knowledge. So ive just got a kriesler model 11-102 and it is a beautiful machine. I knew when i got it it had minimal sound out of the right speaker. Anyway first thing i did was test it and the sound from the right side is minimal on both the T/T and the radio. I went and replaced the cartridge and stylus on the Garrard 60mark2. still the sound is minimal. The left side has full sound. The volume seems to work okay as the left goes loud as and the right does go louder but no where near what it should be doing. so any thoughts? it may just be something simple. ive checked speaker wiring loom, all valves are nice and orange. speaker transformers arent hot. what do you guys reckon?

With a full range, we are forced to sacrifice to some extent on both ends. OK. My question is for smaller drivers, FE85, RS100 etc, where we are pushing our luck to get down in frequency. To achieve a subjective overall balance, how much hump before LF roll-off do folks prefer, and how much early roll-off on the top? How much does it vary as you do push lower?

I ask as I have seen diligent efforts and done so myself to get 80 to 15K or so quite flat, but they sounded like crap as desktops. Measured several micro-speakers, ( Warfdale, RS, and no-name) All had quite high Q alignment and early roll-off even though they all had tweeters.

They were used in JVC speakers packaged with their executive stereo systems. Are the drivers available separately?

Thanks to all, as always.

Hi all
Trying to adjust the antiskating force of my “SME 3009 II Improved” to suit the needs of my SHURE M97xE which is equipped with a brush damper, a few theoretical questions arose. Surfing around for answers three articles caught my attention:
1) B.B. BAUER: “Tracking Angle” (ELECTRONICS March 1945) [http://www.helices.org/auDio/turnTable/bauer.pdf]
2) J.K. STEVENSON: “Pickup Arm Design” (WIRELESS WORLD May-June 1966) [http://www.helices.org/auDio/turnTable/stevenson.pdf]
3) JOHN WRIGHT: “Bias Correction and Dynamic Conditions” , HI-FI NEWS October 1969
[archived at 09 March 2004 at www.Vinylengine.com]

In 1) Mr. Bauer provides the means to calculate the skating force across the arm’s travel, provided coefficient of stylus friction "mu" is known (he estimates a value of 1/3).
In 2) Mr. Stevenson estimates the lateral thrust (i.e. skating force) as 20% of downward pressure.
In 3) Mr. Wright explaining the results of his experiments, he comes to some conclusions, which seem to contradict Mr. Bauer theoretical calculations, like ” Bias force is therefore substantially unaffected by the surface speed” and “Bias force is therefore substantially unaffected by the playing radius”. The reason of the discrepancy is that these results (as also Fig. 5 and Fig. 6 of Mr. Wright article) are based on experiments conducted on unmodulated record grooves. At the end of his article Mr. Wright deals with modulated grooves and their effect on skating force. He concludes that “Bias force is therefore substantially directly proportional to modulation velocity-at least for sinewaves” . His Fig. 7 provides experimental data for friction coefficient ”mu” .
Combining formula from 1), and ”mu” data from 2) the attached drawing was produced. The 6 thin curves represent the skating torque produced when an elliptical 0.0003x0.0008in stylus hanged on a radial arm with the geometrical data of an “SME 3009 II Improved” is reading a record with grooves modulated with signal of varying modulation levels (0dB refers to 1cm/sec at 2 kHz).
Two things become easily evident:
a. The skating torque variation due to modulation variation is 30%.
b. The curves follow the form of the well-known tracking error curve.
Both smell trouble.
Practical antiskating mechanisms do not adapt automatically to increased skating torque due to varying groove modulation.
Practical antiskating mechanisms do not provide an antiskating torque, which follows such a curve.
(Continues)
George

Just wondering if there is a proper way to terminate the output so to test output level with 1 volt P-P input. I'd like to compare my Aikido's for output level

Bought Jamo 507 Speakers last week. Beautiful cabinets. Cones all good. Unable to test. One speaker has very low volume. Switched out speakers with other. And still low volume. Switched channel on amp. Switch wires later. Tried All the combos but still low volume no life. no obvious signs on crossover. It’s almost like open wires are crossed someplace. can't get To the woofers buried deep in the cabinets. Sure would appreciate any clues.
And by the way the good speaker sounds amazing. Wow. I think it’s called the Denmark sound.
Connected second set of speakers to amp to confirm both channels work as should.
Thanks folks

I'm running out of space in my lab and need to clean it out so I'm selling a few things I no longer need or haven't used in a while. Open to reasonable offers.

AP SYS2722 (see my separate ad) $9500

Shipping is not included on the following items:

Audio Precision AUX-0025 Switching Amplifier Measurement filter including $95 rack mount kit: $900

AP Rack mount kits -RAK-212 for AUX-0025, etc. and slide mounts for the 2722. I bought a box of these and it contained more than I needed, most are brand new: $35/set for new, $25/set for used

Eico 666 Tube tester (solid state) works, clean for it's age but has a flakey test switch, manuals included: $150

Datron 1062 6-1/2 digit multimeter not working (EEPROMS probably need to be reflashed), display lights up, beryllium copper binding posts. $40

I'll post pictures and more items later

Hello,

When looking at Alps Alpine RK271 series potentiometers for volume control of line in on a LM3886 chip power amp, what difference does 10K, 20K, 50K or 100K make?

Anyone know where to find a 10K version right now?

Mouser is sold out right now, Parts Express sucks shipping to Canada and I am trying to avoid a counterfeit one off Ebay.

Thank you,

David.

I was excited to find this little gem for under $500 initial testing looks good, so far....


8808A

I thought that speakers setup in a circular array like the Tekton Double Impact and Impact Monitor were not a good idea. Are they able to get away with it because they are tweeters?

I'd like to know whether this kind of configuration could work well with full range drivers and what benefits it would have (beyond just efficiency)? Any potential drawbacks like comb-filtering and what does that sound like?


Impact-Monitor - TektonDesign LLC

Hello, I've finished making Chiomenti's "Lo scherzo" whit ECL82 tubes and I must say that it plays OK, even though I don't have very efficient speakers. However, I noticed that in one channel, precisely that relating to the O.T. on the right (see diagram), it was initially buzzing. The problem is that at first I was running the 8Ohm output through the wire just behind the power transformer.
Now, I ran it around the case like the diagram. The buzz has decisely decreased but it is always slightly higher than the other channel. Moreover I have the perception that it is a little bit louder (tried with listening in headphones because I did not feel it with the speakers).
Any suggestion for this?

Forthermore, since I wish to use it also like an headphone amp because low wattage, what kind of adapter could I think of for proper running? Thanks.

Hi all!

I wonder if people might be able to give their advice on this, please:

Hopefully I am moving soon and the place has just been rewired (UK NICS cert.) and I need to build a rack for my system that has to run from either one or two (depending on suggestions) mains sockets.

Gear:

Computer
USB Sound Card
MiniDSP 8x8
Parasound Zamp Amplifiers x 2 (mids and tweeters)
Behringer NU1000 (stereo sealed subs)

Furman M10X Power Distribution

The caveats are:

- Computer and MiniDSP must be on at all times
- The rest of the system including TV/monitor must be powered on by the Furman power unit.
- Ideally should be run from one power socket if possible


I don't jam dat volume too hard but watch do movies with dynamics. I can't imagine I draw that much current for the whole shebang.

Attached is a schematic (and blank) of the system. Apologies for the fruity-tooty colour scheme.

What do you lot think? This is basically how it is now and I get bad noise from the USB soundcard but I think that's another issue to do with the cheap PSU in the computer and/or unavoidable system noise from ground loops.

If you have time to have a look and make a suggestion it would be most appreciated.

Cheers!

Sorry if this might be a newbie question:

The background to my question is tube testing with uTracer 3+.
Often when I test allegedly NOS and used tubes, I get low plate current than what stated in the datasheet for specified conditiions. I read in few website that using fixed grid voltage is the wrong way to do emission testing. Here is my question:
Let's assume I test EL84 in the following conditions-
Va=Vs=250V
Vh=6.3V
Vg1=-7.3V
and I get the following results: Ia=30mA, Is=3.5mA

When I increase the grid voltage to -6V, I get Ia=48mA, Is=5.5mA

How one should interpret these results?

I have to say that I'm not in the position to trust the uTracer yet and currently I have no another tester to compare with.

Thanks!

Hi everyone!

I was given an Altec Lancing inMotion IM7 a while back and I shorted the subwoofer amplifier accidentally trying to mod it. One of the IRF7379 chips caught fire and burned up two small parts near it.

The IRF7379 I replaced:



The two smaller parts: (One of them says "KA2" and the other says "Z 2")



So far what I have done:

1) I replaced the IRF7379 that burned up. (Amp worked but had crackling noises)

2) I removed the two smaller parts and replaced them with others from another channel's amp, sound improved but horribly distorted at high volumes.

3) Removed the two replacements, put them back where they came from, and left the solder pads empty. No crackling but horribly distorted at high volumes.

^This is where its at now. What are the two little parts and where can I find them? Ive looked all over and don't have a clue. Also, what else could be wrong and causing the distortion?

Thanks in advance! If its totally screwed I guess I'll just have to buy a shiny new IMT810 haha.

Noob speaker box size help.

Hello everyone! I'm a newbie embarking on my first diy 2 way speaker build.I've read a lot of info on d.i.y. speaker building but can't understand a word of all the technical aspects. Basically I bought 2 Seas p17re h419 woofers and 2 seas 27tdf H1211-6 tweeters for the build. But for the life of me,I can't figure out the actual box size for them. The seas woofer specs say that vas for the woofer is 30.5l. Does that mean the actual box volume? Can someone help? Tia!

Any infos are hard to find over the web, any chance that could be change is count, so let's try 😉

I have Audio Institute VR-70E (widely known as Dynavector VR-70E) where originally a pair of 6F2 is on board. Not bad Chinese Valves, but there's always could be better. I've tried 6U8A RCA, but ECF82 Polam goes much better. Those Polish Tube Valves sounds better in overall, but there is a annoying problem with vocal sibilance (especially "S" syllable).
Is there any good sounding ECF82, 6U8A, or 6F2 known by anyone? Preferably with good dynamics, good bass control, smooth mids and without overbright hi-end?

PASS ALEPH 5, finally finished the realization of this finale.
Thanks to Maurizio for the inspiration and Eugenio for the technical support.

For Sale: Tubelab SE PCB Version 1 (original board)


I have a Tubelab SE PCB original version that I never used and I’m clearing house. It’s in (as new) condition. Its been stored in its original shipping and stored on the shelf in a plastic tote since I bought it. I built the Simple SE first and then went down different roads and never got back to it.


Also included is a DVD published by Elector all about Valve Amplifiers.


$45.00 shipped in the USA. Paypal.


Thanks.

For Sale: diytube GetSetGo PCB.

This is a PCB to build a directly heated, Single Ended Triode Design tube amp.
It comes with printed instructions to build the amp which includes parts list and schematic.

Probably not for the person attempting there first amp kit (unless you’re an electronics expert just getting into amp kits).

$45.00 and I’ll ship it at my cost if in the USA. Paypal.

DIY Audio Electronics from Zynsonix.com: DIYTube Get*Set*Go Single Ended Amplifier
Get*Set*Go--6B4G or 2A3? | Audiokarma Home Audio Stereo Discussion Forums

Thanks.

This is a fairly recent part, which looks to promise a fairly simple 20W Mono amp. Further, it looks to have a DIY friendly SO-16 package, with 50 mill pin spacing. But the devil is in the details. Here's the spec.

http://www.mouser.com/ds/2/115/PAM8320-273748.pdf

My question is about whether it is even possible to build an amplifier powered by a single 12V source.

The backstory is, I was considering these very inexpensive and ready made STEREO boards, based on an older PAM8610. You may find these interesting too, especially at this insane price...

PAM8610 Digital Amplifier Board 2x15W Two Channel Stereo Class D Sale - Banggood.com

I inquired to Diodes Incorporate whether i could couple the inputs together on that board, and also couple the outputs together, maybe through 0.1 ohm resistors (to add balance) and a 4 ohm speaker. The engineer at DI responded saying it would work, but it would be more efficient to use the MONO 8320. But looking at the data sheet, I'd almost get the impression it requires three power supplies (one bi-polar supply and a separate supply for the preamp / logic section.

Again, this is a pretty new offering so there is not a lot of example applications out there. I've requested some samples, but if I can't use it with a single 12V supply, its not going to be a very useful part for my needs.

thanks for any assist/advice.

One of my old developments: usb interface ui-01

Galvanic isolation Si8640 and Si8662. Clocking from the DAC / ADC board, power supply - primary AMS1117-5.0, then DC-DC at 3.3 V and DC-DC at 1 V to power the core. All connection schemes are based on datasheets. 1 input line, 1 output line. Self Power, i.e. not from USB.

PCM Data I/O 16-32 bit, 44.1-384 kHz, 2 I/O lines (stereo in + stereo out)
DSD data output: Win - DSD DoP 64-128, Linux: DSD native 64-256.
8 GPIO lines with the ability to install Si864x isolators.

MCLK - 512fs

My end goal is:

1. Single ended with choke CCS
2. 40W into 16 ohm @ 1% THD.
3. 100 ohm output impedance or more
4. At most 100W dissipation
5. As little feedback in loops as I can get away with

A variant on the Big MOFO or similar with a frontend would be perfect except it has a low output impedance. I could wrap a current feedback loop around it to raise the output impedance but if I've understood correctly I'd have to use a lot of feedback to get my desired output impedance. And in addition to that I don't need the distortion reduction of the feedback, it already performs good enough. But could I do the F7 trick but in reverse? That is I use a modest amount of positive voltage feedback to raise the output impedance by a lot in addition to a normal negative current feedback loop to prevent instability.

I read somewhere that Nelson wrote that the F7 positive current feedback was 2 dB and reduced the output impedance by 30x. If the same trick works in reverse with positive voltage feedback then I could get by with less overall feedback to get my desired output impedance which would be great.

And so I threw together this circuit. If I've understood correctly the drain pins are inverted relative to the gate but the source is not. Hence I believe that the circuit will apply negative current feedback and positive voltage feedback. Unless I messed up somewhere which is pretty likely 😀

And as I write in the example I'm not sure if Q2 should be connected to Gnd or the current sense. My gut says if it has the same ground as Q1 it won't apply any positive current feedback but I'm no expert so I might be wrong =)

Are there ways to DIY clone LS3-5a at reasonable cost? The cost or cloning difficulties with expensive drivers or crossover? Thanks

For Sale: John Coltrane “Interplay” 5 disk box set issued by Prestige


I bought this box set while in college and listened to it straight through one time. It has been stowed safely in a plastic tote for a few years. My job has me travel throughout the US South and East sometimes to foreign lands. I need to move again (for my job) and I am cleaning house. My tastes have changed and I just don’t listen to it.


The set is in “as new” condition and includes the book articulating the time and era these recording occurred. I don’t think I ever even thumbed through it.
$50.00 shipped in the US. Paypal works best. Thanks.


Review here: Interplay - John Coltrane | Songs, Reviews, Credits | AllMusic

For sale a complete set of pcb + 4x5LN01SP + arduino nano
25 euros + shipping



IMG 20200811 114541 2 — Postimages

I am strugling finding the propper mica insulators for these output devices.
I looked at Digikey and, can't find those!...
What are you guys using?. These are for a Kenwood KA-701.

I have 4 used audyn 10 uf caps. One lead on each is cut.
$50.00 usd plus shipping for all 4.
Thanks,
Evan

Modelling this in Winisd.

How is a 4th order with an "infinite" sealed chamber any different to a ported box?

Cone excursion models the same, but the frequency response suggests there will be an 8dB gain at 18Hz.

Is this actually going to be the case?

The "port gain" graphs for the two enclosures are basically identical?

Hi,

Maybe someone knows. I’m mounting a horn on top of a bass reflex cabinet. I need the wire from the horn to run in the box via a hole. Is there some kind of small metal grommet I can use to accomplish? I’ve seen some backs of systems and there’s some kind of small grommet but all I can find is shelf pin grommets or fabric ones (the rest are large for like desks and power cables).

I’m using 1” solid wood so I need a finished look.

Thanks in advance for your help.

A Samsung AV Amplifier delivers its output into 3ohms on all channels. The system sensitivity of the speakers is quoted as 86dB.

The driver in the sub was unserviceable. It has been replaced by an 8ohm driver with a SPL of 92dB.

(1) Is the balance between sub and satellites pretty much where it started?
(2) Will the change in load have a detrimental affect on the amp?

Despite thinking i would buy a volt + amp i think i would go for this amp (price power ratio)

AUDIOPHONICS TDA-S50 Amplifier TDA7498E Class D 2x 50W / 8 Ohm

AUDIOPHONICS TDA-S50 Amplifier TDA7498E Class D 2x 50W / 8 Ohm - Audiophonics

I have a 24v 6a power supply but i can get 2 power supplys so the total price would be no more than around 70 euros

ALIENTEK AC/DC Switching Power Adapter 100-240V to 28V 4.3A

FX-AUDIO AC/DC Switching Power Adapter 100-240V AC to 32V 5A DC

What is recommended to buy? Any other suggestions from a european store?

Say guys, i found 2 dreadded black flag caps in my integrated amp!😡
I found these: 399-9787-ND # at Digikey. Would these be suitable please?.
The OEM's are 100PF. Blocked

Thanks guys!!!

Hi there,

i've got myself an old Ampeg B15 N which had his original 110v power transformer switched to an Ampeg european 220v one.

It all works, i mean, i can plug a bass/guitar and ear it coming out of the speaker.
but i have a relatively quiet but unbearable oscillating noise at all volume. (The noise's volume changes with the amp volume.)
i've changed the pre tubes and the can cap, still the same problem.
Here's attached a sample of it recorded through my phone pointed at the speaker.

does anybody know this sound ? and of course, does anybody know from where it could come out ? what do i need to check ?

i'm not a high level electronic guy, and don't have a variac or an oscilloscope.
only a multimeter, an iron and some common sense.

thanks in advance,
Fred.

Hello everyone! I'm a noob and want to build a 2 way speaker using Seas p17re h419 and Seas 27tdf h1211. Despite reading so much on this topic, I can't understand what's T/S parameters etc to determine box size for this 2 way speaker. Can someone help? TIA!

I bought a Wilson Benesch Circle about 15 years ago. My local Linn dealer adapted a Lingo 1 (year of production 1993), this was possible because the synchronous motor is similar to the motor of the LP12. Everything seemed to work properly.
But last week I checked the output voltage of the Lingo. It starts with 95 Vrms (stall mode) and changes after a few seconds to 60 Vrms (normal mode). So far so good, but afterwards it toggles continuously between the two modes. If I removed the belt i.e. no-load operation of the motor or changed the speed to 45rpm, but the behaviour remains unchanged. In stall mode the motor produces audible and sensible vibrations, therefore in the moment it would be better to feed the motor directly with 230V line voltage. I found a complete circuit diagram of the Lingo 1 in this Forum, but did not understand the control circuit. Maybe someone can explain to me which parameter forces Lingo to switch into the stall mode? How can I find out if its a problem with the Lingo or the motor? Would a recapping solve the problem?

Regards
Martin

Anyone have a schematic or kit for a remote control for my pre amp?

This amp is using MTP50N05E as the power supply fets .

Would the 3205’s be a good replacement ?

I have a technics sl-ps900 that has stopped reading discs not sure weather it is a capacitor problem or laser was going to change the whole laser tray mechanism off another model to fix it but not sure what other models use the same mechanism ?

I recently built an 12AX7/KT88 prototype (I do not have "current" schematics for it, sorry), and I think it sounds good, but it is not very loud. I seem to be about to get around 100dB out of it on-axis from about only a foot away from some crappy desktop speakers. I'm also going for more hi-fi than a guitar amp, so I don't expect maximum gain(and I realize a negative feedback loop is missing, not relevant to the question however), but I'm still trying to figure out a few problems.

I looked up Uncle Doug's tutorial on how to measure power output from it using a 1kHz signal on an 8 ohm dummy load, and from my memory I was only getting a few watts (literally like 3W) out of it.

I'm powering it out of an old iPhone which I'm estimating only puts out about about 250mVrms.

Also my OT is a Hammond 1628SEA from Digikey (https://www.hammfg.com/electronics/transformers/audio/1627-1642.pdf). It's a 5k input impedance to multiple outs(I'm using 8), supposed to be rated for up to 30W.

I understand different frequencies will have different responses, etc, but I wanted to try an exercise in LTspice to see if I could work backward, even if strictly theoretical and possibly unrealistic, and just pump in some raw numbers to see what I would get out.

Here's my slop-matic:



There are many obviously unrealistic things about this schematic, but for the case of modeling, the idea was to swing the grid between -5V and -35V against a 530V B+, using a model(hopefully correct) of the OT matching the Hammond, into a dummy 8ohm load and see what I would get out. In this case, I was getting about 3.2Vrms across R10, which should translate to about 1.28W.

With the OT windings being 25:1 for 8ohm, my guess were that if I wanted to get this to 10x as much (12.8W), the secondary would have to swing 32Vrms, which means I'm at 800Vrms on the primary, which is more than B+ supplied even if I'm going after the opposite swing from the transformer.

I guess what I am trying to do is start a design again, working backward, and figuring out what I need to feed the OT, then what I need to feed the power stage, etc, etc.

I'm sure the things I'm doing wrong are almost innumerable, but if someone can point out a few big hitters, I can get my mind back on the right track.

Thank you!

I have been thinking of doing a new F6 pcb to implement some of Nelson's updated circuit ideas as well as some of my own.

As well as a B1 type circuit that was presented by Nelson at one of the BA festivals.

I would intend to make it available for store use.

Is this something the store might be interested in.

Another AG9016 "addict"

Hi,

first of all my copliments on this forum, especially the links on tube related articles, often on entry-level, are very very helpfull.

As a brief introduction, I just finished (re)building my first EL84 SE amplifier (Kontakt KT7). Although I bought the amp in "working" order it needed some new capacitors and a by-pass of the input section in order to get a reasonable sound.

After a while I decided to fully strip the amp, and rebuild it from scratch with new (and preferably better) parts, and although I had minor knowledge on tube electronics, I managed to get it up and running again.

I am actually working on a site were the rebuilding process will be described in full with detailed pics, and as soon as it is finished I will drop a link as I feel that this could be interesting for other applicant Kontakt/Bocama/Lafayette rebuilders.

Now only recently I bought a philips AG9016 amp which is the next project I want to dig in to. I have read the topics on this forum on this amp, i.e. 40 yrs old philips AG9016 flea-power ?,
and there seems to be somesort of "improved" schematic were most of the C's and R's are removed?

There was actually an article in a magazine called A&T (!?!) how to "pimp" this specific amp, but somehow I cannot find it anywhere on the net.

To make a long story short, all (schematic) information, additional tweaks etc., are more then welcome !

Thanks in advance

Cees66

I'm trying to get amplification to drive a single passive 12" PA system, rated at 200 RMS, and an additional passive 12" subwoofer, rated at ~300 RMS. The amps will run off a buck converter connected to a 12v deep cycle battery. I'm looking for cheap, powerful, and energy efficient.

Right now I'm looking at buying two TPA3255-based amps:
AIYIMA TPA3255 Subwoofer Power Speaker Amplifier 300W Mono Hifi Home Audio Amplifier NE5532 OP AMP Bass Treble Adjust|Amplifier| - AliExpress ($45 each)
and run one in PBTL mode and one in SUB mode. It seems that the input power is limited to 35v, so I think this will give me ~120w RMS at 8ohm, for ~90$.

I'm wondering if there might be a cheaper, more powerful, or more energetically efficient solution. One idea I've been playing with is using a single TPA3255 with two output channels (2x300w), feeding in a mono main PA signal on the left input and the pre-filtered mono subwoofer signal as the right input. This would let me get away with using a single amp, for ~$50, also I'm imagining ~120-150 RMS at 8ohm, and possibly half the energy use. However, I'm not sure if this is feasible, in particular if feeding in main PA/subwoofer signals as left/right differential inputs is a good idea.

Any advice or thoughts would be appreciated.

I'm upgrading to a (far more expensive) audio precision system.

Selling a lightly used Quant Asylum QA401 Audio Analyzer & QA450 4/8 ohm load.

Comes with accessories and cables to measure your DAC, amplifiers, speakers, etc. SNR, THD+N, crosstalk.. Lots of insights.

QA401 Audio Analyzer



– QuantAsylum
QA450 Programmable 8/4 Ohm Load [Retired]



– QuantAsylum

$500 + Shipping for both.

I would consider selling the QA450 separately.

I just finished building a Nutube B1 and a ICE Power 500ASP + 500A module. I noticed an increasing high pitched noise coming from the 500ASP though, the 500A seems fine and Im not sure what can it be. Im using star ground at power supply and connections seems as 500ASP user manual



Any tips on where to start debugging?

Quick question; I'm thinking of doing a 15" build with the above horn, or something like it. I want to WAF it as hard as is practical, because whilst the new other half is quite prepared to let me build whatever I want, I don't want to look at an ugly speaker! How thick can you get away with painting the horn before it is detrimental to performance?

Cheers,

Russ

Brian Bell Chipamp.com Aleph Boards + Power Supply Board. They have been in my parts drawer for many years...

How about $40 shipped CONUS?

Please ban the term "Chi Fi" from the forum. It is an example of cultural racism. I know that not all people, including forum management may be aware of modern forms of racism, so I will spell it out. Chi Fi is cultural racism because it's very usage implies that "Hi Fi" is the normal state, and "Chi Fi" is the non-normal state, and of course normal is therefore not Chinese. Research racism yourself if you do not accept this.