Hi.

Anyone got any of these they are happy to sell?

I'm in Guildford, Surrey, UK.

Thank you, David

Is it acceptable to have 39mv voltage ripple in a power supply without load?
The power supply is as follows:
secondary power transformer 2x390 VAC -> RECTIFIER TUBE 5U4 (5V DC FIL.) -> C=30μF -> L= 4.5H -> C=100μF -> L=4.5H -> C=100μF
-> 550VDC and ripple = 39mV.
Thanks in advance for your opinion.

SOLD

4 available
ship from France

Make me an offer

EDIT:
One pair left: 40€ for the pair, excluding shipping.

Here are the shipping options within EU, at your choice and responsibility:
with tracking, with insurance: 12.50€
with tracking, without insurance: 5.22€
without tracking, without insurance: 2.36€

I need ltspice model for jfet 2SK162 and 2SK163.
I have some of those from a friend. At datasheet, 2SK162 have very low noise at 5mA drain current.
May be it suit for moving magnet pre-amplifier.

Hi Guys ... I am building a Push Push RIPOLE sub with two 15" drivers.

The driver should have the below characteristics for RIPOLE.

Low Fs
Low Cms (around 0.2mm/N)
Qts around 0.5
High Xmax

Is this understanding correct? Did I miss anything or wrong about anything?
Please suggest guys....Thanks a lot in advance.

The below are only for reference
Jazzman's DIY Electrostatic Loudspeaker Page: Ripole Subwoofers:

RiPole Subwoofer

I finally got the binary sequence CNC'd. 4 of 120 by 60cm. 2 positive and 2 inverted with 12.7mm diameter holes.

Unfortunately the only nice laminated bench tops MDF's were in 18mm, I am aware the Bad panels are usually 9 or 12mm thick but I don't think that will cause any issues.

The other thing is that I will be placing them over my current panels, which won't give the same low frequency absorption but still provide enough absorption under the 1000hz mark.

I want to place one front wall and one back wall and the other two in direct line of fire of my horns. The horn speakers are toed in and the line of fire will be the opposite side wall.

Does it matter which location I use for the positive or inverted panel?

Also the orientation does it matter?

And any other advice for placement?

Of course measuring is best approach but once I've added them it's hard to change so I might have to go with the stick and leave it approach. So any recommendations will be appreciated.

Croft "Vita" Line (6SL7) & RIAA (3x 6N9S/6H9C) Phono Preamplifier - Schematic here

According post #8 under
Croft Vitale
this model is short-lived and thus rare.
Check also this thread:
Croft pre-amps differences.

Test review is here:
Croft Vita | zStereo

Here the datasheets of the used tubes:
''GSTube.com''. Tubes, sockets etc. Parameters and characteristics 6H9C
6SL7-GT pdf, 6SL7-GT description, 6SL7-GT datasheets, 6SL7-GT view ::: ALLDATASHEET :::

In the attachment sketched schematics which I have create and various images of this pre-amp device.

Follow deficiencies I discovered at first look:
1) No capacitor for input load of connected MM cartridge (phono input)
2) No bypass capacitor at input and no capacitor at whole at output of 12V voltage regulator (go to image No 8, post #2)

I would like to convert the line gain stage into a cathode follower without gain (buffer) and enhance the idle current from 1,4mA to 6-8mA. Is this possible with this tube without reducing life time ?

IMPORTANT NOTE:
I have stopped this group buy. Please do not ask me if you can buy a bunch of BC550 or BC560 transistors.

------------------------------------

This is a group buy for BC550C and BC560C BJTs. These are the "original" OnSemi/Fairchild parts, which are now obsolete.

Some hFE readings and curve traces are attached (I used a DCA75 tracer for this, so it shows only the low voltage/current part).

The BJTs come in bags of approximately 100 pieces. Each bag is CHF 20.00 (shipping is not included).

To sign up to this group buy:
(1) Reply to this thread with a complete copy of the list, and add your diyAudio name and the number of bags to the list.
(2) Send me a PM with your full name, shipping address, telephone number, and PayPal email address.
(3) I will send you a PayPal invoice.
(4) Once I received your payment, I will send the BJTs to you.

Note: this is a first small round for the group buy. I have only a few bags at the moment, because I ran out of packing materials. Depending on how this goes, I may consider doing another round.

----------------

Hicoco: 0 bags BC550C / 2 bags BC560C
thimios: 2 bags BC550C / 2 bags BC560C / PM with details sent
thermionic: ??? bags BC550C / ??? bags BC560C
cambe: ??? bags BC550C / ??? bags BC560C

Hello,

Does anyone have any experience with a stuck lid of this cd-player?
For sometime it worked very well, but recently it got stuck and i don't know where to begin to repair this.
The player thinks the lid is open, but in fact it is closed....How to reset this thing? Anyone?

Best regards

Hi, I have a stash of these small transistor-like things and I'm having trouble identifying them. Assumed NPN and E-B-C order, a sampling of three gave an hFE of 58, 73 and 118 and no other values for other pin combinations or PNP. They're marked as follows:

"script F" S20264 719

I'm guessing Fairchild? Does anyone have a catalog for obsolete Fairchild semiconductors that lists specs for these, or can provide the specs to me?

Thank you!

I’ve noticed an odd thing happening when typing in the text box while using iPadOS (15.1) and Safari.

When I tap backspace to correct something, iOS or Safari keeps the deleted text in the suggestions line above the keyboard. It’s weird. I haven seen that before.

See attached photo.

I just discovered that it doesn’t happen with Opera…

A friend of mine somehow blew a 270ohm 0,25 watt fusible resistor in a sony ta-313 amp which I refurbished for him...I dont know how as he didnt answer this question so far so I think stupidity was the culprit. Any idea how to substitute this r, I cant find it anywhere.
Thank you!
Arne

I was just thinking, if vacuum tubes had never become "obsolete" in the market. Do you think the generation of electrons to create the space charge would have advanced to some method other than thermionics, heat + chemistry? Is there any way in the science of today that an abundant quantity of electrons can be freed in a way where we could have had a tube that never "wears out"? Maybe using a small power laser in the tube? Plates, grids, beam formers all can last multiple lifetimes, the filament/cathode can't,. I just wonder if a tube that generates electrons reliably for a lifetime is possible today, but maybe wasn't in 1973 when plants started to close down.

I have two questions. In the picture, it calls for a 12nf cap across the 6.8k resistor.
I have some 18nf caps in my collection. Would it hurt/degrade the amp if I were to
use the 18nf caps? in place of the 12nf caps?

Question 2, how do you set the bias on this amp? I cannot find any documentation
on it.

Thanks

if my understanding about BSC is correct, is it possible to implement BSC by choosing a woofer with 3-6dB more sensitivity than tweeter? something similar approach is taken in case of 2.5way speakers. My requirement is to implement BSC without including extra passive components? any other such techniques or methods to avoid BS?

Hi All.

I picked up a stack of 3 way crossovers that were, according to the vendor at a local electronics surplus store, pulls from a theatre that had replaced its entire sound system. These crossovers have no documentation, and I don’t know what drivers they were used on or the impedance of those drivers. I used the parts from a few of these crossovers to build a couple of pairs of simple 12 DB per octave two way crossovers, but I have several left and would love to learn more about them as built and in their original form.

I have a attached a photo of the crossover, and of a schematic I made up by tracing the circuit. My questions are about the components in the crossover that I have circled and what purpose they serve…

1. What is the purpose of the resistors circled in blue? The two that are in between capacitors and ground? The one that is positioned in front of the .56mH inductor?
2. Does the 51 Ohm resistor circled in red work with the 10.1 Ohm resistor in series with the tweeter positive output as a voltage divider to reduce output?
3. What does the .51 mH inductor circled in green do?
4. Are the three components circled in purple a shaping circuit/EQ for the tweeter?

My apologies if these are newbie questions, and thanks in advance for your help

Earlier I posted some test results for AD SAR ADC.
Follow the same procedure, I put mcp3562 on my test bench as DUT this time. To my surprise, SD adc shows astonishingly good results.

Sampling rate 62.5 kHz. FFT-32k, test tone 2kHz (there is an inaccuracy on TFT screen, it reflects 1kHz for 31.25 ksps).
MCP356X Linearity test. - YouTube


Waiting pcm4202 to compare with, my promised by Friday delivery was delayed.
Stay tuned.


****************************

31-08-2021 Updates:
Code mcp356X_h743zi2_forum_5dx.zip - Google Drive


I have no plans to develop this project, harry up if you have any questions regarding to code, till my Alzhemer hits me hard 🙂

DIY Sound Group has restocked some speaker kits. This is the last chance to buy the Vortex 12 coaxials. The Jeff Bagby-designed Helix dome MTM kit has also been restocked. Not affiliated with the website, just a very frequent customer who knows that inventory has been hit-or-miss so I want to give folks here the drop.

Class D circuit LM311 This circuit uses up to 4 sets of feedback. and the audio input signal must use two phases again if This is considered a very strange and detailed cycle. To capture the back signal in both phases and the most balanced There are four wires, feedback back is a H bridge.
(The circuit is based on the PCB. but not yet tested.)

I was busy today. Went to LOWES to get some plywood to experiment with some open baffle speakers. Walking through the masonry department I spotted these cement half blocks....Now these might make a great set of desk-tops. Certainly rigid enough! Should be fun!

The Danleysound TH28 is a 2x8" TH with an Fb somewhere in the low 40s. The dimensions are of interest though. Almost a perfect fit for my car's small trunk. I'm curious if it might be possible to DIY one that's slightly larger to fit two 10s that has an Fb at or below 40 Hz?

Hi everyone

I want to plug my Cronus into the i2s header of a minidsp and then the minidsp i2s output into my buffalo dac.

Has anyone else done this? Id love to hear how you solved it.

In order for Einstein to be right, there has to be dark matter but nobody so far has been able to detect dark matter. There are competing theories that modify our understanding of gravity, but they are at best incomplete.

There are situations where dark matters are better suited, whereas others where modified gravity are better suited to explain.

I think it all comes down to our human inability of understanding the worlds. Quantum theory and general gravity are both incomplete.

These two videos serve as a short summary of dark matter vs. modified gravity.

Dark Matter: The Situation has Changed - YouTube

What If Our Understanding of Gravity Is Wrong? - YouTube

Hello,

Long version: I'm fed up with bluetooth speakers. Had a JBL Extreme before, also a larger one with handle (not sure the name), it is good for music like techno I guess, but that is not my taste. Both had poor mids. Than, I planned to modify my Dynacord Mosquito S boxes, create smaller, half boxes, but finally decided to skip that.
Than, I found an old box, a half Focal Poliglass V2 component set (after the first set failed, I was so stupid to buy Focal again, the iron core got rusted and stuck. One side was repairable, the other side not, it ended up in it's box for several years). So, I found this half side and decided to make a mid size, transmission line style speaker out of it. I'm very surprised how successful this became. It had mids, deep low, not too much, but accurate, tight and pleasing highs. Interesting, despite it is mono, it has space, it is living. ... driving with my single ended class A triode amp.
Than, I've tried with this : https://www.aliexpress.com/item/32891062619.html?spm=a2g0o.9042311.0.0.27424c4dog7218 . TDA7498 based, built in BT receiver. It has a good base, but the enjoyable mid and high gone. It is loud, but I rather decrease the volume, not up :-(
Now, I would look for a class D amp module, I would prefer a mono module what I can run from 18V battery packs (cordless power tool battery, Lidl parkside). Not sure what advertised power should I look for, but I think it would be about 40W if it would be a normal class B amp. (this speaker can handle quite high power). Do you have a suggested amp module, from Ali if possible, which could bring the nice sound back? Not with built in BT receiver. Another bad thing about this module I have, even the smallest volume setting is too high. I have a good receiver module, which sounds good too. More looking for an amp, mono, about 40W real, 18V single rail, but most importantly, what sounds the best from these cheap modules. On the other hand, I will not buy an x hundred EUR module for this project. I hope you can help me to find something good on Ali for me.
Thanks a lot,
JG

During the course of the past 10 years I have been prototyping some 40 tube based audio projects.
All kinds, SE, PP, PPP, Circlotron, Current Dumping, SE Spud, PP Spud, Phono, OTL, SMPS, conventional PS, Hybrid etc.
None is a straight copy of a published design but different tubes, redesigned circuits, cheap OPT a.s.o. but all work well within their limits.
Lately I ran out of ideas for audio, so during the last 6 months I tried something different, non audio:

A 24 Hour Digital Clock with just 16 Vacuum Tubes which could have been built in the 1950's.

Background:

To my knowledge no all tube clocks were built in the 50's or 60's.
Only four attempts to build such a clock in modern times are known:

Nr. 1 is a project which took an individual enthusiast 10 years to complete, 97 vacuum tubes plus 6 nixies:
http://www.jogis-roehrenbude.de/Leserbriefe/Bruegmann-Digital-Roehren-Clock/Digital-Roehrenuhr.htm
Nr. 2 was a cooperative semester project at Technical University of Berlin, sponsored by a company and on display at a sales show, 70 tubes plus 6 nixies:
https://www.emsp.tu-berlin.de/menue...nik_back_to_the_roots/die_digitaluhr_oncilla/https://www.emsp.tu-berlin.de/fileadmin/fg232/Lehre/MixedSignal/Dateien/Back2TheRoots/02_ONCILLA.pdf
Nr. 3 is based on a set of vintage Beckman counter modules, modified for nixie display, 30 vacuum tubes plus 6 nixies;
https://linearlook.com/eldocountry/projects/tubeclock.html
Nr. 4 is similar but predates Nr.3, 30 vacuum tubes, display has 10 indicator lamps per decade:
https://www.selectric.org/tubeclock/
There are clocks out which use decade counter tubes for display but all the difficult tasks are done by a microcontroller like in this one:
http://www.tube-tester.com/sites/nixie/different/e1t-clock/e1t-clock.schem.pdf
All four serious vacuum tube based clocks use flip-flops for counting.
And because it takes 4 dual triodes per hexadecimal digit plus a couple more to do the reset trick at 10, 6 and 24, this is where most of the vacuum is spent.

My thinking was that if I could avoid flip-flops and the associated logic altogether it should be possible to get away with a lot less.

Now, the Philips E1T Beam Deflection Counter Tube, does the decimal counting all by itself, displays the result, resets itself with the 10th pulse, provides a carry signal fto trigger the next stage, acts as a storage device and even allows readout of the stored number, albeit in form of an analogue voltage on pin a2 proportional to the displayed number. This works backwards, too, and can be used to preset.
https://www.radiomuseum.org/tubes/tube_e1t.html
Unfortunately the official application documents for the E1T require one E90CC pulse shaper per decade for 30 kHz operation and two E92CC per decade for 100kHz.
http://www.tube-tester.com/sites/nixie/dat_arch/E1T_Philips_Book_1954.pdf

I want to make sure a contemplated suspension would isolate at the right frequencies. The motor is a Hurst 600 RPM /60 Hz. What would the primary frequency of vibration be? Are there sub harmonics to be concerned with?
Thanks,
Marty

I've been asked to show the power supply I'm using with my preamp design posted in the "tube preamp" discussion - so here is the circuit first:

As you can see, at t=0s the speaker is at max extension with pressure max outside the cabinet. Inside the cabinet we have pressure min. At t=0.007s the wave has traveled a quarter wavelength and the pressure is zero inside the cabinet. Also, at t=0.007s the speaker has returned to zero extension with pressure zero. If the pressure wave is released from the enclosure at this time, it synchronises with the pressure wave emanating from the speaker, and doubles the amplitude at 34Hz...Sweet! 😱

If we wait until the wave has travelled half a wavelength, the pressure inside the enclosure would be max and this would sync with min pressure emanating from the speaker, cancelling the pressure wave.

Did I miss anything? Can I build now?

One of my two NHt A1 amps occasionally has no output until I cycle the power switch. It is set for auto power on, and the LED indicates it is powering up upon signal, but no output.

Any chance someone has a schematic or source for one?

Sounds like a simple relay issue but a schematic would be very helpful.

Thanks,
Jeff

I bought an ads pq8 off eBay without the DIN plug.

I figured it wouldn't be a problem buying a plug and wiring it up, but....

It's an 8 position male DIN and I went over to Digikey and struck out. (But found documentation for a promising spec - SD-81)

Seems there is a 270 degree style and an unattainable 262 degree style (not stocked).

So on to amazon with no luck. And on to eBay where I found some what didn't look right ("U" style 262 degree).

Does anyone know a source for this plug?

Thanks in advance,
Dan

Anybody have a manual or schematics for this critter? Thanks!

Globes only, directly or indirectly heated. Highest I've noticed is the 56 which has a mu of 13.8. I've seen pentodes with much higher mu but only when used as pentodes and when triode wired their mu is lower than the 56. Can't say as though I've done an exhaustive search, though.

Wondering if there's anything between 13.8 and, say 100 mu.

I was given these tweeters for free after an amplifier purchase, but realized the two do not have matching impedances. I checked them on the DMM and one shows 3.9 ohm while other shows 7.9.

Looking at the certificates, both are consecutive serial numbers and both played fine when hooked up at low wattage.

I have too many projects to mess with them or experiment but the mismatched impedances concern me that someone else couldnt enjoy them.

what am I looking at here and are they usable for someone?

Does anyone have data on any of the Mac amps with meters in them? I have an MC420M here that I’m modifying, and I need the pinout of the plug that goes up to the meters from the main PCB. I’m thinking all the models are probably the same, so anything will probably get me close whether it’s a 431M, 443M or 440M.

The meters on this amp were both inop, so I’m installing OLED screens with ‘needles’ animated by Arduinos. If I get the info I need, I’ll post back a video of the final result for you all to enjoy.

I have a UNI-T UT61E, the version with less protection. Does anyone know the MOV's reference of the version with more protection? Thanks

https://image.ibb.co/fQs2yH/Uni_t.jpg

I have been having a bit of a problem trying to locate low noise transistors....

The threads that were suggested when I started this one have been followed and yielded some info, but nothing that I can really use.

2SB737 was discontinued years ago.

2SA1085 seems to have been discontinued in the past year or so.

What is going on in the world of electronics?
Why are these useful parts being discontinued?

What parts are being used in low-noise applications?
Does anyone have any suggestions for low Rb transistors?
Through-hole and surface-mount devices are both acceptable.

Typical applications are RIAA preamps, microphone amplifiers and summing amplifiers.

Any help or suggestions will be appreciated.

Thanks,

Gareth.

List country in title. Some ppl will not purchase or sell items outside their country.
Sorry if it was addressed, just I waste a lot of time looking.
Thanks
P.S.
So far looks good and #1 IMO

I'm trying to communicate with members of a group buy but I'm limited to 10 new conversations per day. Is there a workaround for this? Is there another membership level where this limit is lifted?

I like this particular model Oppo DV-980H DVD player, as it has a pretty good picture for a DVD player, good upconverter to 1080p, HDMI output, and a USB socket on the front for playing MP3s. It also plows through most CD's, CD-R's, and DVD's almost no matter the damage. And one can pick them up pretty cheap on craigslist, so now I have four. Can't have too many spare parts right?

This mod is NOT quite housebroken as it lets loose a nasty thump every time it's switched off. My own woofers are real tough, but buyer beware.
So next time I try this mod, I will look into using the on-board muting circuit. Also my thump is made worse by the large 7.6uF caps I'm using, as Cirrus calls for 3.3uF.

Thanks to GaryB for pointing this out: The datasheet for the CS4361 shows how to connect it so that it requires no opamps. Use Fs=192000 and Rext=5000 in the equation below the diagram (attached), and C=10x10^-10 = 1000pF.

Output is lower than the stock 2V, I'm guessing about 6dB lower, so just over 1 volt? I'll measure one day.

I'm also using a switching regulator Murata 7805SR (~$10) for the 5V to the DAC.

Prefer to sell as

Four Tube Lot = $60

or

Five Tube Lot = $75




Priority US shipping adds $8.20 to either lot. (FWIW used a couple up front in my old 2A3 amplifier)

You can buy whatever quantity - shipping for 1 trough 6 = &8.20 in a small Priority box

Paypal only

I had an issue the other day with the heater wiring in my Tubelab SSE amp. I turned the amp on in the morning, and no sound. This was odd because I listened to the amp just the evening prior and was really enjoying it. I noticed that the power tubes and driver tube were not glowing at all. The rectifier was glowing and was getting hot, but the other tubes looked off and were not hot to touch. I then turned the amp off, unplugged it, and flipped it over to see what was going on.

I've attached a picture to this post. The brown wires connecting to the 2 position terminal block are the heaters. You can see that one terminal looks burned or scorched. It looks like the plastic has melted, there's some sort of brown goop on the wire coating, and the screw is stuck but good - I havn't been able to turn that screw. The heat damage is only on the one side of this 2-position block - the other side looks fine.

When I started investigating further, I noticed that wire was not cinched down well in the terminal block. It could be pulled in or out w/o undoing the screw (which in a sense is good because I can't undo the screw...). Could this bad physical connection be the cause of the melted plastic? If so, I'd be grateful if someone would try to explain to me how that works. I've got the board unconnected now to do some modifications to the chassis and to add a big motor run capacitor. When I put it back together, I'll be much more careful with all of the terminal block connections, making sure the wires are all cinched down and snug. I've ordered a new 2-position terminal block, but is there anything else that I should check or be worried about before firing the thing back up?

Thank you all in advance for your help!
Dan

Offered here are some Caddock TF020R's that were just carefully removed from an old ESI lcr meter than has been gathering dust in the warehouse for 20+ years. It was a one-off model with custom frequencies, made for a nat'l lab facility in the early 80's. They are all 0.01% tolerance and 10 ppm/°C tempco, and in excellent condition.

Link to the data sheet is: http://www.caddock.com/Online_catalog/Mrktg_Lit/TypeTF.pdf

Price is $4 each, with flat $4.25 shipping via 1st Class Parcel in the ConUS for any quantity. Values (and qty) available are:

1k0 (5)
2k0 (5)
3k9 (2)
5k0 (2)
9k0 (1)
10k0 (30)
16k0 (3)
20k0 (10)
40k0 (1)
40k5 (1)
50k0 (8)

Paypal is fine, no added fees. (No F&F, please...)

Blasphemy? Or practical? From some of the description words I've seen: separating the speaker from the floor, how do spikes even accomplish that? They look cool. Would it be more ideal if the speaker was resting on a silent bed of air, like a shuffle board table? Then a happy medium: caster wheels. Provided they are of some quality not to rattle! Any thoughts?

Here's the one I'd probably go with, "raises furniture 1 3/4in" which is close enough to the 2in I'm going for.

https://hardwickandsons.com/products/solid-brass-pivot-plate-caster-3-4-wheel?variant=12150348873803

Anyone have one laying around? Lemme know.

Looking for a pair of these amp modules.

Hello,

I'm new to uCap12 (and simulation in general) and I'm trying to import and simulate a PSpice (.lib) model file which I downloaded directly from TI.
I have copied to .lib file to the main LIBRARY folder and then used "Add Part Wizard" tool to import the model, I selected the 6 pin op-amp model and renamed the pins as they appear in the model file (.SUBCKT lm3886 Vip Vin VDD VSS Vout MUTE)

I constructed a simple circuit and wanted to run the simulation but when I do that uCap shows me the lm3886.lib file and highlights a diode model:

".SUBCKT IDEAL_DIODE_0 A C
+PARAMS: EMCO = 0.01 BRKV = 60 IBRKV = 1M)"

I assume the lm3886 model is relying on another uCap native diode model to work, and that is missing?

Any ideas of how to get it to work would be much appreciated.

Thanks!

I'm considering creating a spectrum analyser using this ADC7768 based development board - at 256KS/s 24bit:

https://www.mouser.co.uk/datasheet/2/609/cn0540-2256468.pdf

This seems to provide a very good starting point for an Arduino based ADC for analysis software (ie python or other) that could run via USB.

Any thoughts?

Hello

I made this circuit and I want to have the same gain on both outputs. Presently, OUT 1 has near 3.5 times more gain than OUT 2

Ideally, I would like to get OUT 1 gain with OUT 2. Any suggestions ? Thanks.

Hi,

Does anyone know where to buy custom aluminum faceplates at a reasonable price?

I tried Front panel express which was Schaeffer (I think?) back in the days and was quite happy with the price/result but now it's definitely out of my budget. Plus I don't really need their new design software stuff.

It's just a 2mm thick anodized aluminum sheet with a bunch of punched holes, probably some milling for the preamp meters and a good silkscreen ink (Ideally subanodized labels). I'm surprised there's not a huge chinese factory selling this to non-professionals yet! Or maybe there is?

I used to buy aluminum sheets and drill/silkscreen by myself 20 years ago but unfortunately I do not have access to this awesome workshop anymore.

I'm based in France/Switzerland.

Cheers!

Looking for a single or pair of Hypex Fusion plate amps, 3-way models, either the 123 or 253 please.

Ideally UK based.

Cheers, Rob

I am currently repairing an old school sound stream reference 500. The only issue remaining after replacing the output transistors is a constant 35AC on one of the speaker terminals.

After searching through other threads, I’ve determined that the rectifier(s) are more than likely causing the issue. Can anyone tell me what the best substitute for these rectifiers would be? According to the schematic, I would need to find substitutes for the FED16BT’s used in this amplifier.

It is an amplifier in class D type digital self oscillating feedback with feedback before the coil.
Input sensitivity 200mV, gain 150, feedback Integrated Loudness, the amplitude of the triangle 6Vpp, the switching frequency of 360kHz.
The output coil are wired in anti-phase to minimize EMI and are ferrite cores EI 40, air gap 3 mm, and has 14 turns.

Bridged amplifier is powered by a switch mode power supply 138V / 23A. IRF644 mosfets are always three parallel, contains current protection. Amp I used for the construction of system LRAD (Long Range Acoustic Device) and supplies the piezoceramic 1000W / 16kHz
https://www.lradx.com/


It hysteretic power oscillator and oscillates on the basis of the delay quality triangular wave is better than an oscillator which oscillates on the basis of the phase-shift (feedback per coil)
Also the quality of the triangular wave in this type of oscillator controlled better than D amplifiers.
Transistor BF423 converts the output of the comparator between levels of supply + -15V to -70V on Wednesday because logic 4030 is powered by a plus 5V to -70V and IR2110 plus of minus 12V to 70V.
The potential difference is 85V, because the converter BF423 between levels at the input gate 4030 to 5V.

The quality of a triangular wave, which in this case, the amplitude depends 6V audio amplifier and its size does not affect the volume, as in controlled D amplifiers.

The result is that amplifier idle effervescence nor gain at 150 or even 1000. (gain in almost open loop is 12000, where it is still stable. Then it vibrated wave 10Hz)

The first OA that has the input lowpass filter, because if you have unshielded wires and has an entrance next to the exit, overwhelm, the support and influence of positive feedback grows multiple volume.

The second OA inverting integrator which is coupled with the inverting comparator included feedback.

The third is the integrator of the second half bridge and the audio signal is non-inverting, the output is then the voltage in the opposite phase, the speaker is connected between the outputs of the bridge, which is twice the voltage and approximately four times the performance.

Gate 4030 forms a deadtime generator 70ns and resistors 100 ohm to the diode before MOSFETs formed Ug, resistance delayed and diode serves to fast discharge gate, so that at 400kHz was not against each other and avoid shocks, needle overshoots that may damage the transistors and also burden the crossflow end degree and reduce efficiency.

Start oscillator takes place in hysteresis mode. The comparator due to its own large amplification opens (at that time has both inputs zero voltage) BF423 closes lower mosfets are opened and the comparator waits until the charge pump, it takes more cycles. Output becomes 430kHz harmonics, which increase tension and to the feedback reach the flipping of the comparator back deploys oscillations.

When switching into the outlet or power outages, or transition from Standby, or to shorten it does not wound to the speaker because the PNP transistor BF423 is from around oscillator fastest to open the first and thereby prevents the charge pump until the voltage source again stabilizes.

It is very convenient for the construction of the amplifier in class TD in the function of the power source and the active filter D carrier for amplifiers in class AB, B or just
Fitting into AB amplifiers including SMPS power they have the power to 140V. The exercise of the amplifier is compared to the original about fourfold, limited only current through the BJT, which is set at D.

The AB is not performed interventions, but it is advisable to disconnect the Strangler in bases exciters terminal transistors, which originally served as protection against short-circuit and if this involvement makes possible, eliminate, or reduce the emitter resistors just to remain feedback for controlling the quiescent current, because they consume power and the load impedance can be halved. It's also good if AB is a provision in the current amplification in order to not spoil the effectiveness and symmetrically limited.

To D feedback resistors fitted with the same as in the original AB to make it go together. In the preamplifier output to connect -IN OA to have gain first

The output of D two fast rectifier diodes and through the choke to supply AB. If AB has on board some great Elyte so disconnected. To cover current consumption and cross some AB 50 mA to 150 mA at a time when it is idle D just above and below the filtration 1u / 400V.

The first harmonic 360kHz whatever is necessary to 5V is not a problem, AB transistors for it permanently nonconducting, and if there are other things hang together, preamplifiers, indicators, and also supply channeling D carrier.

If AB had previously difficulty maintaining quiescent current depending on the temperature, so he injected into feedback pure first harmonic 360kHz few mV and feedback control the bias current from the deck.

The switching frequency can then be reduced from 360kHz half to a third of the integration Article 10k of about 200p in feedback, performance by even a few hundred watts to grow.

Benefits AB class are retained, D deficiencies and suppressed class as a
whole, it does not heat up.

.

Can I get some advice on how to put my digital music on a dedicated laptop, notebook with a 1 TB hard drive and then stream it through wifi, or even connect it by USB to a WIFI AV Receiver so I can play music on my speakers and/or listen to movies on a good speaker system. And the essential issue is what and where do I get a stand alone music player to organise, shuffle and make playlists of my music when I am not connected to the internet. Please don't say Apple, iTunes, or internet streaming as these are vampires who want your blood.

I love the internet. I can shop, investigate, ask for advice. But the internet really screws you over when you want to play your own music.

Absolutely fed up with Apple monetising iTunes, actually destroying it and selling streaming music. I had my CD collection in my iTunes library, now it is Mac Music and really nothing works. First I had to get back to my 4,000 song collection which meant deleting down from the 16,000 songs Apple bloated it to with duplications. Up to 5x for many songs. Apple of course says it is user error, but it is really Apple using Catalina to force users to accept the destruction of iTunes so you will get fed up and pay them to listen to their streaming. I tried to work within the Apple system only to discover that even though they say we can use MacMusic for free and play out own collection, nothing works, they cannot find the file for the song, even after you delete the old song from the library and then reload it from your CD to the library. Apple messing' wit you!

I don't want to be "playing" with Apple's idea of what I am to listen to.

I want to listen to all my old CDs now stored on my own internal hard drive, and not have to go to iCloud to do something else. Is that asking too much? Apple thinks it is, because how can they make more money if I don't play with them?

Can you help me out with a stand alone digital music player that can give me control over my personal music collection?

I Have a Heathkit TT1 tube tester. All the wafer switches [approx 18] have a considerable amount of metal mold buildup. I have tried deoxit but will not breakdown the mold. Thinking of using oven cleaner but not sure. Any suggestions much appreciated.

Thanks,

Cags

Hi, regarding the sealed back midrange below:

https://www.precision-devices.com/products/all-products/pd-615n002/

Many of the T/S parameters are N/A, is there a way around this with the impedance chart? try to ask the manufacturer? Or is active the only option?

Trying to get a general consensus on how low a center channel speaker needs to go? Is 80 Hz OK?

I'm in the middle of an W-M/T-W design (woofer on either side of mid/tweet with tweet above mid in middle. Woofer to mid crossover point at around 600HZ; mid to tweeter turnover at 2.8K. with what would be superb null response when mid out of phase (showing near perfect in phase at respective crossover points).

I picked some very good/cheap 5" woofers (Peerless 835024 Aluminum cone) for bass that will perform in sealed enclosure(s). They will however only give me -3dB at around 80Hz (9 litre enclosure volume per/driver). I dislike the sound coming from rear port(s) of a vented center channel speaker that resonate within the TV stand cabinet it's placed into. I can set the AV receiver to only deliver sound down to 80 Hz for the center speaker (theoretically remainder goes to sub) for this setup but should I worry about going as low 60 Hz or less for Center Channel?

Came across this extremely simple cs8412/PCM56 on AliExpress but it does not include a 74Hc hex inverter. Isn't the inverter necessary?

Edit: never mind, figured it out.

Some R2R DAC designs appear to achieve "24bit" processing using two 16bit chips segmented into MSB and LSB paths. One DAC is sent the upper 12bits and the other the lower 12bits.

Is that feasible with the TDA1387?

Will it lower the noise floor and increase dynamic range?

Could it achieve 20bit linearity?

Can the digital data segmentation be processed on available PC software, so a PC with a USB-I2S multichannel device can do the work and save on IC's?

Hi all and happy Christmas,
I've just finished two 80 cm tall speaker stands made from fir wood, regarding the vertical supports, and multilayer plywood for the bases. I wondered wich kind of dye/varnish were suitable for both materials. Asking to a friend who is carpenter he told me that I should use two different kinds of treatment: mordant or water-based color followed by gloss or semi-gloss transparent varnish for the fir, and a white primer and specific coloured paint for plywood. My idea is to have a walnut color, a little glossy, for the vertical elements and a glossy/matte black color for the basis. Anyone experienced with that? Thanks in advance

Hi, there!

I have two ESS Heil AMT's vintage that I picked up. I did some testing and I noticed that one of them is about 3-4 db quieter than the other. Has anyone experienced this and does anyone know of a fix?

Let me know!
Joey

Hello I'm brushing off some dust and designing an ADC using the the new ES9822 and I have a few questions about it if anyone here might know the answers.
It's been some time since I've worked with this stuff and I need some intellectual reminders as well as some clarity on the ESS documentation obscurity.


I've been looking at the datasheet here and there are some things I don't understand.

I noticed it mentions the use of a programmable delay to "help with phase compensation when mixing". I have no idea what this is referring to. Could someone clear that up for me?

My next question is about the master/slave modes. I recall the ES9038 having such a thing with the slave mode being superior for some reason. Could someone remind me what the pros and cons of master/slave are?

I've also noticed that the chip has a 2x mode for double the sample rate. I am curious as to the particularities of this as my first thoughts are 2x must be better but obviously it's never that simple. Does anyone know the details and pros/cons of this 2x mode?

Also I'm more used to reproduction than production so can someone inform me of the advantages/disadvantages of i2s/spdif/tdm/dsd output in the context of an ADC?

Lastly are there any particular requirements or quirks with the input to the ADC? I noticed the recommended buffer in the datasheet has some gain reduction and some filtering.
Are there strong reasons for this?

Sorry for all of the questions but this isn't information that is easily available to find if it is available at all.
I would greatly appreciate the insight if possible.

OR TS-350S

Only 9" and in EU, silver or black version. Thanks

Hahahah, this nails it.
wilco?:
“your sons friends know better than to get you started on amps.”

Bright Eyes?:
“You’re nearing a point where you like making pesto more than eating pesto”


https://www.mcsweeneys.net/articles/what-your-favorite-sad-dad-band-says-about-you

Have always had this issue since I built the amp. On startup the right speaker will play static for about a minute before calming down. Left speaker is dead silent. When I built each channel of the amp and tested them separately; this issue wasn't present.

Static Sound

I've tried some troubleshooting steps. When I disconnect the RCA input at the terminal block to the amp board, it's dead silent.
I tried different RCA jacks and wires, same noise.
When I touch the RCA jack the noise goes away faster.
I've used star grounding and both channels are hooked up to the same point at ground on my PSU board. Only the right channel behaves this way.

When I built the amps I checked for poor solder connections and cleaned all the flux off very well, didn't have this issue when I first tested each channel.

The only thing I can think of is, soft start module being on that side of the chassis or something with the speaker protection circuit? Not sure where to start any help would be greatly appreciated as this annoyance causes me not to use the amp as often and I just stick to a smaller cheaper amp build I got from China that works very well.

Hi, a question do you connect the amplifier GDN to enclosure Earth grounding ? (for safety and shielding) or do you only connect the earth grounding to the enclosure and keep the amplifier GND isolated from that ? And does that then provide enough shielding (and electrical safety) ?
Looking for experiences, what is the exact rule and is the electrical rule for safety impacting noise coming from Earth connected to the amplifier GND ?

Stay safe, Thx

I was searching for a few schematics that used the 01A tube just to see how it was traditionally operated. I hit the jackpot, never saw this site before. Big manuals of just about every radio built then. These volumes cost $7.50 each in the 1930's that would be $125.21 in todays dollar. Apparently only serious repair shops would have laid out 125 bucks during the depression for each volume of a 24 volume set like this. Good reading.

http://nucow.com/120,000FREE.htm

We've seen your solid state amps, tube amps, speakers and what have you, but no love for where you do your work. Share your space, and whatever's on the bench at the moment!

Pardon me if this has been discussed before, but I have a question about the input capacitors on this popular tube unbalanced by Broskie:

The Broskie Cathode Follower circuit shows an input cap on the + side, but not the - side of the balanced input.
I was wondering why that is.

I've seen other circuits that have input caps at both inputs, as this nearly identical cathode follower un-balacing circuit. (sorry I would give credit but I don't know the designer of this)


Can anyone comment on the benefit of the input cap at the -ve input, it's requirement, or lack thereof?

Thanks.

I'm looking to build a PA top cabinet with 2-12" and a horn and need help with designing the cabinet. thinking four cabinets total and have them trapezoidal to work together with minimal phase issues. similar cabinets would be the JBL SRX722.

my first thought was to go with B&C speakers and horns. possibly speaker model 12NDL76? And for horns maybe the DE95TN? any suggestions on cabinet design?

*SOLD


I have this amplifier up for sale on eBay and thought someone here might appreciate it as I have. It is in good used condition with very minor scuffs (includes Owner's Manual) NAD T-955 5-channel amplifier. I have owed this amplifier for about 4 years and was in my HT system for 2+ of those years and worked great. I just checked the DC output (>10mV on all channels) and also played music for a couple of hours, just to make sure it is working perfectly, since it's been on the shelf for 18 months unused.

Nothing wrong with it (see eBay pictures), planning a move in a few months and need to divest some of my accumulated amplifiers.

Link: NAD T-955 eBay

PM me any questions and willing to do local pick-up in Novi, MI 48374 as well.

I tried to find lowest input capacitance, SIC Mosfet
https://fscdn.rohm.com/en/products/databook/datasheet/discrete/sic/mosfet/sct3120al-e.pdf
https://d3rx8y505vv2z0.cloudfront.net/uploads/2021/05/C3M0120065D.pdf


I don't know how hard it will be to get them make MUSIC ,



Wont lie SJEP120R100A and SJEP120R063A were something special

And known points ... Question is, if you have an existing passive crossover with known point and slopes, why doesn't simply programming the matching active parameters work the same? Is it even a good starting point?

Well, the pcb is on revision 2 but I'm really pleased to see it belting out 36Vrms into a dummy load and not breaking a sweat (I was). I thought now's the time to over test it. The pcb is expendable as I have plenty more for the batch I need. Gave it 15% over volts on the supplies and wound the frequency up to see where it would start to fall off. 50k... 60k... 75k.. Hang on, what's that smell?. Looked round to see what resembled a volcano coming from the pcb, so quickly killed everything (by that point 80kHz @ a tad under 40Vrms). The offending component was a 10ohm 3W 2512 surface mount resistor. Then it dawned on me. That resistor is in series with a 100nF C0G cap as an RF filter on the output... and I just put a lot of RF through it... I had stupidly forgot about it when I wound the frequency up at full power. The most amazing part is that it still measures 9.3 ohms. I tentatively restored power and the amp was like nothing had happened. There's no better way to get confidence in a new design than to over-stress it and then soak test. Just remember that output filter...

Quick question,has anyone encountered a noisy (intermittent static/pfft type noise) with any of their parts?
Amp is making some noises thru the woofers only,both channels,no signal.I'm fishing and hoping it may be something else.

Right now, I'm looking at two options for a TMW concept:

1) Try to use an additional driver to "steer" the off-axis response (really, create a cancellation/lobe so the off-axis response at just the bounce angle is at a significantly reduced output). I'm not sure if this is possible but I'm thinking I'll try to figure out VituixCAD for this.
2) Put an absorber/diffuser in the bounce path. This would seem to be the easiest option but it's more wide-band than I would like and will look physically large and ugly (basically an absorbing bucket...)

The one option that I do not wish to pursue, in my particular situation, is to put the woofer right down at desk level, because that increases the c-c distance to the midrange beyond the limit I've set. I want the tweeter to be at approximate eye/ear level, with midrange as close as possible to the tweeter.

Thoughts?

I am interested in building a preamp by combining a line stage and phono stage in one box. Specifically, I'm looking at the Aikido boards from GlassWare Audio Design:

Aikido Octal Stereo PCB
Aikido PH-2 Phono Stage

The descriptions for these two boards both suggest their PS-21 power supply. "Great" I thought, "I can use the same power supply for both boards".

I assume it can't be as simple as branching the various +V rails to the two amplifier boards. I imagine I would have to increase supply capacity (transformer? rectifier capacitors? both?). I also assume there are grounding concerns to address. Are there other issues with such an idea?

I just noticed this while browsing the Q-component catalog.

https://qcomponents.ca/collections/...-misco-165-fr08-04-6-5-8-ohm-full-range-93033

https://store.miscospeakers.com/8-inch-single-driver-loudspeaker-93087

Anyone has experience with it?

Looks pretty decent with balanced TS parameters, at least the way I like. 🙂 A bit on the pricey side, approaching comparable - at least on paper - Fostex and SEAS units, for a company not usually associated with hi-fi, though some recent offerings are going this way, namely the titular Oaktron and the XBL2 woofers.

Arcam products automatically turn off (spontaneously).
I found the problem. The reason is the destruction of the soldering of the Relay contacts in the power supply unit. As an example (picture) repair of the AVR 300 receiver. I hope I helped