I think it's time for a more light-hearted, frivolous thing to be annoyed by: Part numbers.

Historically, transistor part numbers have followed one of three part numbering schemes. Some of them were really nice and even told you the polarity and type just in the part number.

However, not all transistors follow this. Some manufacturers seem to have decided to use "secure password generators" to come up with their part numbers. In particular, part numbers like the IPB60R070CFD7ATMA1 come to mind. In contrast to the JEDEC, JIS and Pro-Electron, I like to call this the "Cat barfed on the keyboard" part numbering scheme. Part numbers of this extreme length are a general tail pain when it comes to drafting schematics and are nearly impossible to remember.

Feel free to post irritating part numbers like this here. In case you're wondering where the rant came from, I've been trying to catalog my stock of parts. These numbers are not fun to enter into a spreadsheet.

Hello All,

Here is one I have never come across. A haunted tube!

I have been going through some Type 26 tubes looking for a quiet pair. I plugged in one tonight that made the strangest noises. I mean spooky.

There were two basic noises:

1- a whale song like sound that was reverb soaked. Almost sounds like someone yelling "hello" from very far down a long a train tunnel.

2- (even more disturbing) a laughing sound. Almost like a dolphin-- that laughing noise Flipper made.

This would happen every two minutes or so. Each time the noise was followed by a soft low-level thump.

The bummer about this was that, otherwise, it was a nice quiet, hiss free, hum free tube! One of the best I've come across!

This 26 came with another as a pair. The other one lets out a steady soft thumping noise about once every two seconds.

What could cause this? Any ideas?

It has been humid and rainy here. Could the tube bases, which I believe is bakelite, absorbed some moisture?

Or are ghosts real?

Hi everyone-

Before I dump this Panasonic SA-XR25 I thought I hit you up for suggestions.

It’s at least 10 years old and has served me well. I decided to hook it up after having it sit for a few years. 3 fronts and subwoofer crackle like crazy. If I play around (on/off, switch audio mode), it sometimes will stop and perform fine. But I’m going through all that.

Here are some pictures of the inside. I did notice something which what I’m pointing at. Also noticed the fan no longer runs.

Dump it?

Hello everybody!

Having a little spare time and because I also bought a new pair of headphones (I'm not going to name them, they're not audiophile rated 🙂) I decided to try my hand at building a small USB DAC based on the PCM2707C.

Why? It's plug and play, driver-less, and 16bits are enough for me since they're enough to cover the dynamic range required by all music genres.
24bit vs 16bit, the myth exploded!

Ah... and it also includes a headphone amplifier that can drive 32ohms headphones (the sort I just bought), but it's better if you take a look at the datasheet:
https://www.ti.com/product/pcm2707c.
I chose the PCM270xC flavor because it has improved volume control under windows vista and above (a greater number of steps compared to the PCM270x).

I've attached the whole eagle project, I'll post some PDFs later if needed. I followed closely TI's datasheet, or at least I tried to.
Meanwhile I'd like your opinions on the layout. What I tried to do:
- separate the digital and analog ground, while also keeping a continuous ground plane underneath the USB traces;
- have a separate shield connection, isolated from the ground, with the possibility of connecting the USB shield to the ground in multiple ways (I've found a number of different proposals and recommendation on the topic, all having their good points, see here).

My aim was to create a SMD only PCB, with the routing on top only while keeping the bottom for ground plane. The PCB is hand made, using the photosensitive method, so I wanted to have as little trouble as possible when aligning the mask for top and bottom.

I did not have a SMD 3.5mm jack at hand so I had to use a THD one. Also, originally I planned on using ceramic caps only (I had some 100uF ceramics at hand - but misplaced them 😡) so the output caps became an aluminum electrolytic cap, 150uF from Epcos in parallel with 4.7uF and 10uF ceramic caps in 1206 package.
Al ceramic caps are X7R except the 22nF and 18pF which are C0G.
Al resistors are thick film, except the ones used in the audio path (3.3k, 47R) which are metal film resistors.

The USB connector is from samtec (mini USB type B), I modified the library and I removed the centering pins, also from the connector itself.
The 3.5mm is from Multicomp I think, nothing fancy, the crystal is the most stable I could find in a friendly SMD package.

In the end I used 22nF ballast caps for the crystal as I also could not find the 18pf at the time I soldered all components, and I was eager to get the DAC running.

The LED near the USB connector is fro signaling if there's power on the USB port and the LED connected to the SSPND signal I use it as a confirmation that the device has been enumerated and is active.

Originally I made a fault, by pulling the 1.5k resistor connected to Data+ to GND instead of VDD (3.3V from the internal regulator) but the layout in the archive already contains a correction.

I'll make some pictures of the build later. I'll also try to make some oscilloscope screenshots with how the signal looks like at different frequencies.

So, what do you think?

Hello, I just joined this forum, hope this is the right place to post this. Anyway...

I have Ibanez gsr200. It is an active bass. I haven't played it in a few months but someone asked me that they need a bass player so I agreed. Went to learn the songs when the bass didn't emmit a single db of sound. I replaced the battery as that is the usual problem, but nope. I managed to borrow a bass, but had to return it and with corona lockdown, I can't take it to get fixed.

Also, I have toddler nephews who love that bass because they can turn knobs and who knows how hard they masscared it because one of the knobs is loose (they are banned to get anywhere near to it now). Anyway, I don't know if that's the problem. I opened it and couldn't see anything with my amateur eye.

Anyway, here's the photo. The knob that arrow is pointing at is the loose one. Also, all other knobs have 3 connections to it, this one has two, but can't see a loose wire if there is one.

Anyone have any idea what it may be?

I'm making very slow progress on my 2.1 channel LM3886 & have reached the point where I need to work out the grounding. My previous 2.0 channel LM3886 was essentially permanently ground lifted so I didn't go through this process.

Following the diagram & explanation toward the bottom of this page I think what I need to do is shown in the attached images of my build so far.

Am I on the right track? If so, what is the best physical way to achieve this? Trying to stack 11 crimp connectors onto a single bolt is going to end up a mess, but presumably I can double/triple up wires to crimps?

Also, if I am using shielded cables for the line level inputs to the amps, what should I connect the shield to (if anything)?

hi guys,
i'm searching software to calculate this loading type, bur in particular the triple duts version as the following image:
Imgur: The magic of the Internet

thank you 😉

A pair, almost new with box . Just mount and test only

Asking USD450 include ship and Paypal fee.

Hey all,

Welcome to Project XI.

You may be asking why another audio analysis tool. Well, this is a DIY site isn't it? During the design I'll be checking rigorously with an Rohde & Schwarz UPL.

Highlights:

Isolated USB with LTM2884
Isolated DC input with LTC4365 9-16V protection
XLR input with range selection switches
OPA1612 & OPA1632 input opamps
OP1611 VREF buffers from precision voltage source
AK5578 ADC in 8:2 summation mode with VREF 5.25V for S/(N+D) 118db/ SNR 127db
AK5597 DAC with OPA1632 opamps and relay switched output level
CM6632A with GX3306-J/A clocks
Multiple LT3042 regulators
Isolated SPDIF I/O
Isolated i2s I/O

Watch this space!

Good evening everyone. I just received my dad's old speakers back from my brother. A pair of Sansui PS-100 3 ways. I am looking for driver replacements?

Tweeters ( replaced a few years a go with a $10.00 piezo tweeter. Sound nice clear and crisp. 4,500khz to 20,000khz

Midranges SP-100 ( sealed 5 inch drivers ). 1,500 to 4,500khz

Woofeer's Sp-100 ( 10 inch woofers). 1,500 hz to 45hz

Crossovers are a 12 DB cross over 8 ohms.

I am looking for near original parts of all paper drivers? Where can I go to get close to original drivers or should I have my driver's redone? Please help? Jeff

www.viawave.ru

It has closed rear chamber which correts the problems with distortion and ragged response. Sensitivity is a bit on the high side because of the waveguide, but is that a problem really?


Troels Gravesen has some units and has already tested them and made some speaker plans for it

"Overall frequency response is flat, for my measurements a bit flatter than suggested by Viawave. Measurements suggest 95-97 dB sensitivity in the 1-3 kHz range rising some 100-102 dB sensitivity from 4 kHz to 18 kHz. Quite impressive although I would prefer a higher impedance and lower sensitivity as most speaker constructions rarely require more than 88-92 dB sensitivity. This would also save quite some money in good capacitors for the crossover.


Distortion is very low, even down to 1 kHz @ 2.8V (100 dB) and suggest even an LR2 filter at 2 kHz may be possible, not a common feature of most smaller ribbons.


Impedance is fairly flat and makes crossover work easy. I have simulated the ribbon with four of my constructions and this suggests easy implementation. Due to depth of the ribbon, only modest stepped baffle may be necessary."

Hello,

the Sony SA-WMFP85 Aktive subwoofer makes a quiet pulsating sound when nothings connected, and a continuous loud sound when chinch cable is connected.
Power light and starting is as usual, fuse is ok, all parts seemed to be ok (not burned).
Do you have any idea what malfunction it could be or what should meassure? (Service Manual in attachment)

greetings

My colleague have a Peugeot Partner and he is complaining about the sound, and asked for help.
I made a fast search and it looks like he's not alone with this issue.

Usually I build Hi-Fi and PA speakers and in the cars I've been involved with I have used about the same drivers.
I like high SPL drivers, not fond of these extreme X-max drivers, and for the doors it looks like a 6.5 inch will fit.
Is there anyone out here that's been working with these cars and have a solution ?

BR

Figge

I have searched and found a few conversations about clip detecting but they all appear to be some form or variation of a window comparator or peak level detector which I'm not interested in.

I want to have a preamp input signal clip detector that actually detects a linear non changing voltage (or value) (dc) which occurs when a sinusoidal wave clips, independent of any threshold voltages or rails because I don't know what the voltages are of the input source unit.

I've looked at dc offset detection for triggering crowbar spkr protectors but the amount of time the signal is in clip or just stuck at the dc rail is way beyond useful for detecting small signal clipping for thd reasons.

I've simulated a few sample and hold circuits which sort of work at specific frequencies but not reliably across the 20 to 20k.

I'm starting to get the idea that this is not so simple in the analog world but might not be too difficult in the digital world.

I'm not completely lost in designing in the digital world (but close). However, I envision an adc feeding a pic with a fairly simple numbers watching routine, that'll output a 1 on some io when a certain string of similar values are read in. Just brainstorming here,

Thank you for reading my post

This one is strange, everything seems to be working, even proper current draw. It came out of protection and had full clean audio.
The amplifier starts up like all these do, draws currents then starts, draws 1amp at idle, yet the red protection light is on.
Regulated, rail present. No excessive current.
This is the same voltage latter as the previous amplifier I believe.
Some help.with this is issue would be welcome.

Hi there

Small problem with Pioneer A400x - amp works fine but the protection circuit activates when volume is turned up or down - then the relay clicks and music starts again. It appears that DC is getting to the outputs but only when volume is changed. I can measure it and also see the speaker cone move abruptly when doing so. All voltages measure OK as far as I can tell and the amp sounds good if untouched. Any guidance much appreciated!

I found this 'stereo' 50s 'Hi-Fi' valve amp in a skip down my street and thought it'd make a great low watt guitar amp conversion.

It has ECL83 "TV Tubes" which are a triode preamp and a 2.5 watt power pentode in the same envelope, configured as a 5W push-pull pair with the triodes as a paraphase inverter.

My dilemma is, should I stick with the paraphase or convert it to a Long-tail-pair (differential)?

My understanding is that paraphase inverters are considered older 50s technology and the Long-tail-pair is a 60s "improvement". Bearing in mind that, at the time "improvement" meant cleaner, more Hi-Fi, less tube character and it's this tube character that is exactly what we want in a guitar amp.

So, has anybody had any experience of the sonic differences between these two phase inverter configurations?

Also, the more usual twin-triode (same bottle) long-tail-pair is likely to be reasonably inherently more balanced, where as my separate triodes are not. So, has anybody also had any experience of the sonic effect of an un-balanced phase inverter? Might it be better for guitar? More asymmetrical distortion (even ordered harmonics)?

While I'm at it, anybody know what C6 - R9 is for?

Would greatly appreciate some guidance on this.

Hello diyaudio !
I'm trying to repair a french analog multi-effect unit
The unit is a Europa DP400C.
It's a great piece of equipement... but i cannot find any schematics
Main PT was blown, replaced it with a spare 12VAC PT. Now it lights on.
But some function don't work (delay time is always at maximum i guess, chorus has no effect unless i wiggle the speed knob)
I'm a guitar tube tech ; don't now much about thoose complicated board...
Maybe someone has some time to help me ?
I have a good DMM, a scope, a function generator...
The no-working pots are mechanicaly ok.







potentiometer order :
1st picture
compressor : sustain / level
overdrive : distorsion
2nd picture :
overdrive : distorsion / level
chorus : speed / depth
delay : time / feedback / level


high def pictures :
IMG-20200413-153350 — ImgBB
IMG-20200413-153357 — ImgBB

I have the Mod Squad Line Drive Passive pre.

I also know Pass Labs/Nelson Pass B1 buffer. (never audition)

Are they different? Why can't we call the Mod Squad a buffer or vice versa?

I believe if you have a good sounding amp that matches well with the passive, this should be the way to go. I mean do you want your amp to sound like you want or do you want your preamp to sound good? If you add a preamp and like the sound of your system better, isn't that maybe your amp is not to your liking?

I know it is a subjective thing but it makes sense. Your amp and source have gain in the first place. Why would you want to add more gain with a preamp?

Okay guys, I need some help..trying to figure out what I need to buy so I can replace this. Mg1 311 is printed on it but I can't locate anything? I'll post pics. Its a snap-on timing gun, I know it's not car audio but I also know there are some people on here that will know what I need! Thanks guys

I have to use the super regulator circuit!
I want use the AP2722 to test the performance of super regulator.
But I don't know how to setting AP2722?
I want to test output impedance and LR and noise!!
thank you!!🙂

hello I have a PASS LAS X150 and I want to dim the light of the start-up led, now I have a black sticker so that it does not bother me, I could put a series resistance on the led pin without damaging the circuit.
Cheers

Hi

I just acquired some of these HP meters, which look similar to the 400 series AC meters, however they have BNC inputs on the back and 3 pin miniature power connectors-photos attached

I have searched the web and HParchive, but no joy

anybody have a clue as to model number etc?

Thanks

Peter

Title says it all. Anyone have any of these on a shelf/in a draw that they bought for a rainy day?

I am researching a new project, thinking about the best direction for it and what I need to acquire in terms of reading / knowledge at first. My objective is a monobloc power amp with the following parameters:
· High current / low impedance capability as much as high power. The main speakers I own at present are 90db/W but a demanding load at LF – 4R impedance at 30Hz / 45 degrees phase lead rising to 10R at HF. I’ve been down the high efficiency / low power route and it did not work for me so SET designs need not apply!
· Custom OPTs are OK
· Heavy driver requirements are OK – I will look at choke-loaded / small power tube etc drivers later
· Current production tubes for the outputs
· I want to keep voltages reasonable say 600V max: no transmitter tubes
The following things are maybe ‘in the mix’ for me at present - parallel (perhaps more than two pairs) push pull, triodes, cathode feedback with or without ultralinear taps, generally keeping down the turns in the OPT and / or toroids. What do you all think?
I’ve built a big amp before, it works well and this is my attempt to go beyond it – I know what I am getting myself into!

1 of 3 woofers = only 1/3 of the power needed? && Sealed woofer +tube amp = no sence?

Hi,

could you please do me a favor and answer a few very basic questions. I'm not there yet to answer by myself but need to know earlier than I will be...

At the moment I'm about to get into tubes. I bought a few more ore less broken tube radios to get in touch by debugging. I got basic electronic equipment including an oscilloscope. Contrary to these practical challenges, in terms of the theoretical ones I'm not same completely unprepared because of studying EE. Getting into analog electronics and audio motivated by the goal to make it to decent tube sound in my room is what I'm about and what also the current status is: just started to reach out for skills and hardware.


Please have a look at these speakers:



When they were launched in 2013 two of them were £2400. They are not built/sold anymore but Teufel refers to "their next generation" called Teufel Stereo L which are £1580 for two (but are actually quite different ones).

Somebody wants to sell me a single one of these woofer chassis for £80 (...or 70 I think). The manual says (look at attached pic), that the amp should provide at least 50W. So maybe it's meant, 50W in total for two of them or 50W for a single speaker? Anyway if we forget about the koaxial chassis, there are either 3 or 6 woofer chassis which this minimum of 50W is devided into. So is it correct, that an amp for a singe woofer chassis should provide at least 10W/20W? (This could be realised by tubes in the future.)

Because these speakers are a sealed concept (each woofer by itself, seperated rooms inside the speaker), they are not very sensitive... 85dB as you can see in the attached pic. I thought about a sealed box with the same volume as one woofer got in the original speaker and some kind of big horn construction attached. Does this make sense to you or should I stay away from this woofer chassis because it needs way too much power or should not be run seperated from the other two woofers? -Or both or even because of other reasons?

A woofer like this additionally to a bigger subwoofer chassis would make much sense for me because listening a lot to music where bass is absolutely important (like dark psy, progessive, hardtek....). It could perfectly be used as a kick bass I suppose.

Lets not think about crossover (yet). The main question for the moment is to buy or not to buy. So help me out with some expertise, please. Is much appreciated.

Thank you guys a lot!

Hi Everyone,

During quarantine I have some more time for my projects. I orderered a couple of PCB's for Samuel Groners Laboratory grade measurement preamplifier and I also wanted to order all the parts through mouser or digikey.

Most of the parts were easy however there where a couple that are now end of life and I'm having trouble finding replacements.

Here are the transistors that I was having trouble with finding a replacement or would like confirmation for.

Type - The replacement I have found.

MMBF5462
BC850CMTF

I have also posted this in as a reply on the thread about the preamplier. However nobody seems to reply there 🙁
Unfortunately the manufacturer doesn't provide a replacement either.

Thanks in advance!

Hidde

DIY FirstWatt Pass B1 w/ Korg Nutube Preamp

Unit works perfectly

Build notes:
- Remote controllable volume and input selection
- Ultra transparent relay-based I/O selector and volume attenuator
- 2 inputs/1 output as built.
- External AMB sigma11 linear regulated PSU with oversized transformer
- Front and rear panels milled at FPE
- Front panel volume level display
- Parmetal Series 20 aluminum chassis -- 12" x 8" x 2"
- 2H distortion set at 9.5V, per Pass default recommendation
- Extensive use of EAR ISODAMP SD125 for damping the Nutube, relay strip and top and bottom chassis panels. This significantly tames the Nutubes microphonic ringing.
- Nichicon Muse UES coupling caps, Panasonic FC caps for CRC. Vishay-Dale RN55 and CPF3 resistors.
- Korg Nutube B1 Preamplifier PCB + Fairchild JFETs – diyAudio Store
- 6moons: audioreviews FirstWatt B1 with Nutube

- Expansion options:
- Blind holes in rear panel allow for expansion for 4 inputs and 2 outputs
- A pot/knob can be added to the center of the front panel to control volume manually in addition to the remote control

Asking $500 shipped, which is about 30% less than what the build costs.
If there isn't much interest, I may wrap this up and use it in the future... it is a great little unit.

P.S life changes require full downsize of my system and projects, all of which I will be selling.

The x16 has better specs on the converter but is the result of different chips, different topology (parallel adcs) or just a simple lack of preamps in the way to mess with the measurements?

Additionally, the merging technologies AK8Dp seems to be summing 4 converters on each channel, and still not achieving the same specs as the X16 (123.5 db vs 124 db dynamic range on the input)

The THD+N of the MT is -110Db vs the x16 which is -129db!

I'm still leaning towards purchasing the MT hapi, but I want to know if the spec's listed by the apollo are feasible. It seems so if they arrange the right components correctly... Perhaps there is an 8 channel AKM ADC that can provide these specs in mono mode?

The inside end my port has a grille not dissimilar to this Tuff Cab 75mm Bass Reflex Tuning Port Tube with grille from Tuff Cab PS0.35 IN STOCK (12 Apr 2020)


Does it affect performance?

I was the speaker engineer at Alesis for a few years and accumulated a bunch of evaluation drivers, primarily for the M1Active 520 monitors. I am under strict orders from my wife to get rid of all unused electronics (like that's going to happen). I'm appeasing her, for now, with these guys, which are decent Chinese samples. There are 10, 5.5" poly woofers, 4 assorted fabric tweeters and an 8" poly woofer. These aren't going to be mistaken for anything Scandinavian, but they'll make a decent small monitor with the right crossover. Pics can be seen here:

Amazon Photos

They are free with one condition: you have to make a donation to your local food bank for whatever you feel they're worth.

Local pickup in the Los Angeles area unless you want to pay shipping for a 40 lb box! Contact paulbf99 (at) yahoo (dot) com

hello im not good at english exusme
i have a circuit for truck 24v to 12v (20 amps) for drive led and amplifirs and recevers and ...
lm2576 is good but i have 20 amps
can you help me?
thanks

Hey guys,

anyone with experience repairing crown xti 2000 amplifier?

Need some help.

amp power button is tuned on all leds light up but it just stays at that point, the display does not come on and the relays stay off.

This is the public release of a number of enclosure designs for the Fountek FR88ex. The original plot was a low budget, decent quality multi-media speaker for your 'puter (sponsered by Byte Computers in Victoria).

Scott from Woden, lent me a hand, and boyz being boyz, a couple bigger boxes came into being.

We have built 4 of the 5, and the fifth (the Fencepost) may be completed by a regular beta tester.

http://p10hifi.net/FAL/downloads/Fountek-Five-planset-030412.pdf

These are free for non-commercal use, have at it.

dave

The problem of standing waves in any speaker design is a serious consideration (though there are many ways to get around the problem), in a TL design it is no less critical.

Yet most TL designs are of the "box type" where the labyrinth may not have many right angles, it is nevertheless enclosed in a simple rectangular box with at least two parallel sides.

One way of reducing the standing waves in a regular speaker design is to design the enclosure so that there are no parallel sides.
Can this be done with/for a TL design, or is it redundant and otherwise too expensive?

I bought two very nice Plitron PCB transformers on eBay, model 8980-B2, 0-20-120V and 0-100-120V inputs, 50/60Hz, 2 X 18V output at 0.56A and 1X10V output at 0.43A. I thought I might design a PCB to use them. But it's unlikely I will ever get around to learning PCB design and doing it.

So here's my proposition: you get one transformer in exchange for designing and ordering two PCBs, then you send one PCB back to me.

Used with 120v primaries. Model AT/D3040. No VA rating on label. Ships with hold down cover and bolt, upper and lower gaskets and two bridge rectifiers with heat sinks attached. If you have use make an offer. Heavy, actual shipping cost added. Item SOLD

Hi,



I have a problem with my old mission cyrus one.

Two weeks ago the right output stoped working. I continued using it and now also the left doesn´t work anymore. It didn´t stop immediately. At first it was some kind of distortion and than it stoped completly.



The fuses are ok, the headphone-output still works.
I read in this thread that one thing to do is to replace some caps.
Would that be worth trying in my case?


Or is it more likely that the transistors are blown up, like I read here?



Any other ideas, what could be the problem?


I have some knowledge in working with electronics and soldering. I´d like to try to repair it myself if possible. But I never repaired a amplifier...


Thanks so much for help!

Hello,
Does anyone know where I could find a service manual or schematics for a Clarion 1122HA car amplifier?

Good day,

I am thinking about making some nice speakers for our kid’s playroom (3x5m, ceiling at 2.5m). Fixed mounting in the corners of the room to both save space and save the speakers from being moved around by the little ones 🙂. As I have a pair of Visaton B200 that is not being used, I found the Solo Eckbox design here:

SOLO Eckbox | Visaton
Not a very difficult build, but I would prefer something even simpler (like, for example, not needing a sealed enclosure). Ideal would be a 30-40cm wide board attached to the (whole length of the) wall, and use the open space at the top and/or bottom as some sort of vent (there will be some opening as sealing it nicely against the ceiling and floor is not easy…)

I found the Pensils: they are not sealed and need an opening at the bottom. I need to read more on them to see if an adaption would be viable.
Another option: At work, we have an Ultimaker S5 that could be used to print the parts for a back loaded horn or something similar.

Do you have any ideas or suggestions? I am open to buy a different pair of full range drivers!
Many thanks, Erik

are the cones used in 18w discovery drivers identical or is there any differencies to the cones? the cones for 8424 feels very soft and flimsy and not semi ridgid as one described the cones for 8434

All,


Would it be an option / good idea to put a different woofer in the 4645 ?
More output, more Xmax etc ?

I have a pair of these on hand. Wondering about opinions on the 2269 in a 5ft. cab with a linkwitz transform circuit. They have huge Xmax and I don't need 130db spl. TIA

Hey guys just thinking out loud what is the smallest driver used on Transmission line, horn or bass reflexes, have you done it and on a tiny driver would it be worthwhile as a way of making bass and other frequencies sound bigger than what it is?

I recently made a Bose clone using the visaton BF37's which are small and it made me wonder what a TL or horn would sound like and would it be worth it...

I recently watched a video by hexibase which sparked my interest

YouTube

I've just re-capped my 3020 series 20 (I believe it is). The amp now sounds balanced and clear through my workshop test speakers. I've fitted the 1k resistors across R653/4 (470 ohm on mine) according to the instructions for the bias adjustment, but I get readings of around 300mv across these. I didn't expect it to be this high, any advice on this before I proceed?

Here is the Lundahl PCB board for TU-8800

I have a Sennheiser HD598 headphone currently used with the headphone amp section of a Tianyun Zero DAC with very good results. Just for the fun of it, I decide to build a solid state separate headphone amp. I found the YuanJing assembled board at a very good price.

https://www.yuan-jing.com/e19-class-a-headphone-amplifier

I was attracted to its all descrete, MOSFET output section design. It has uPC1237 Speaker Protection Chip. The producer indicated high quality parts are used. But I cannot find any schematics or circuit information.

I picked it over the Lehmann or Beyerdynamics clone. I already ordered one and it should be here in 2-3 weeks. Anyone has tried it before?

Edited September 15, 2016:

The E19 headphone amplifier board is NOT recommended for reasons that nattawa posted in #2. The hum problem is fixable, but you have a better, similarly priced, choice in Weiliang E5 board.

I wanted a front-end input using Marantz HDAM input structure，2SK170 matching of 1% for differential input, fully complementary MOSFET output, uPC1237 Protection Chip, and at least 500 mW into 50 ohms loads. The E5 board only is getting difficult to find, but fully assembled version with case is still available at good price.

http://www.ebay.com/itm/Finished-E5-Class-A-hifi-Headphone-amplifier-with-ALPS-potentiomer-115V-230V-/191869579640?hash=item2cac517178

I've designed a rotary table that's easy to build and only requires two door hinges for the pivot action. The plans are free to download on my site.
This allow you to make accurate off-axis measurements of your speakers and keeps the pivot point on the font baffle which insures the mic distance remains the same. Using a rotary table allows the measurement mic to stay in a fixed location which minimizes the effects of the room if your making gated measurements. You can also change the design to make it higher if you want to use outdoors.

You can download the plans by clicking here.

Hello all, Confused...I see references to MTP20P10 / MTP20N10, and I look at mine and I see MTM20P10 MTM20N10...

I also read here that instead of chasing these impossible to find original devices, one could sub IRF240 and IRF9140, or the Fairchild FQP33N10 and FQP22P10 TO-220 mosfets

Anyone have any advice?


Also possible to just gut the amp and the chassis is sweet for a Pass jobbie...

My son and his friend have been pranking me with bassreflexboxes for my birthday.

Since I hate helmholtz like I hate root-canal work, I had to take a gruesome revenge on them.

With the help of Hornresp I tried to get as many functional pieces of PVC pipes into one box as possible, and a symmetrical loaded 8th order band pass box was definitely the way to go.

Thanks to David McBeans excellent program Hornresp, designing the 8th order BP was a pleasant stroll in the park.

Hi guys,
can I ask you a quick advice?
I built a 4 channel buffer with two B1 boards and two Biino boards as potentiometers...
The problem is that now I hear a 50hz (I guess) hum coming from speakers... It's not loud at all, but it's there...
Some facts:
- in the buffer the signal ground is not connected to earth
- if I disconnect earth from buffer case, noise is still there
- if I disconnect earth from buffer and the two amps behind, noise is still there
- if I connect signal ground to earth in the buffer, noise is still there
- if I SWITCH OFF the buffer and switch on the amps, the noise is a little lower, but still there
- there's a DC filter on the ac mains that feed buffer and amps

Can you guess maybe where to look better?
Thank you so much, guys!

Hello all. I trust the lockdown held in most countries is bearing some sort of audio video build. Now besides the APEX AX14 im going to build, I was wondering if there was anything else I could build, that is on par with the AX14, using these semi's



IRFP150's, IRFP450's, 2SC3182's, 2SA1265's, 2SA1962's and 2SC5242's.


PCB layout would be great 🙂

I am looking for some pairs of matched original Toshiba 2SJ74 pairs for couple of ACP+ builds. As well as matched pair or quads of 2SK170 for my J2 build. Prefer Gr grade and if not at least Bl. I have the Linear Systems jfets from diyaudiostore but was looking if someone has spares not used so far of Toshiba ones 🙂

Shipping to either India or USA. Please PM me.

Thanks

Sold

Does anyone know how deep the LM3886 is biased into Class A?

I have assembled a Servo-amplifier and there's a slight difference between channels.
It sounds fantastic, so whatever is going on one can't hear it.

I use a 2x40 VAC 2x600 VA transformer for OPS and a 2x12 VAC 1A for driver PCB, and high voltage rails are in series with OPS rails, but with it's own CRC regulation.
Then the regulators leave +/- 60V for driverstage, OPS have +/- 53V with 940mA bias / channel.

Instead of 2N5401/5551 I use KSA992 and KSC1845, and as predrivers 2SA1480 and 2SC3790 instead of 2SA1210 and 2SC2912.
Outputstage use 2SJ79 / 2SK216 as drivers and 6 pairs 2SJ55 / 2SK175.
IPS current is set to 2mA, there's 5mA / 18mA on VAS stage and 28mA on mosfet drivers.

Now to the problem...
One channel have slightly more gain, about 1V from 10 Vrms and up to clip level at 31,5 Vrms (Bad channel) and 32,5 Vrms (good channel) output in 3,9 ohms. When it clips the "bad" channel starts clipping at negative side, positive side clips the same as the good channel.

Distortion at 1 kHz and 20 Vrms out is 0,0035% / 0,0060%, 10 kHz 0,0190% / 0,0496%, and at 20 kHz 0,0364% / 0,0902%, so the "bad" channel looks a bit worse. At 30Vrms it looks about the same, but a bit higher.

I have not been able to measure any differences before VAS-stage, but the difference appears on VAS output.
So is it Vbe or Hfe depending, or may one expect a faulty transistor ?

Best regards.

Figge

I've bought two Sure ADau1701 DSP boards to play with, building active speakers.

In a class D thread I just read:

Turbowatch2 said:

Don´t use Sure DSP. It suck´s.
This one, at close range, is much cheaper. It has all the stuff Sure forgot and you can only add at huge cost´s.
ADAU1701-2In4Out | 3e Audio

Two of them should be enough.

Click to expand...

So... what's wrong with the Sure Adau1701 DSP boards that makes them "suck"?

I am trying to bridge two amplifiers. Neither have a bridging switch. I was told that my amps can in fact be bridged but would need to reverse polarity on one input on each amp. I have searched the internet for countless hours and have not found a single device that will do this. I guess they do not exist. I have two Sumo Polaris amps that I want to bridge. How do I invert the polarity? Can this even be done? Thank you.

Hi all,

Currently, I am building a simple LM1875 based stereo amp for home and would highly appreciate feedback from the DIY audio community.

This is my very first build of a DIY amplifier and in parallel, I am learning to use KiCAD. I will be ordering PCBs hopefully soon and really afraid of any possible issues given my lack of experience is both CAD and circuitry design!

The schematic I am using is nothing short of a good ol' Silicon Chip Schoolies amp with a reference to those $2 eBay lm1875 kits - I just wanted to make something better and learn something new.

I will be using JLPCB to get both PCBs for both amp PCBs as well as the PSU PCBs and will be sourcing components from Digikey.


Small comments about the amp boards - as I mentioned, I tried to mimic the eBay kits - I found a lot of good feedback on that type of a layout.
I also kept the signal part separate from the high voltage components and tried to reduce the amount of traces running parallel. What is not present in the amp PCB is the shape fill - I removed it since it made all the legends and position of the component on the silkscreen unreadable. I hope shape fills help me to minimize the crosstalk if that is even a thing in that case.

I tried to select decent grade components for the board itself without going crazy about audio grade components. I do hope that a couple of extra $$ would help alleviate my infant hardware design skills 🙂

I would highly appreciate the reviews of the schematic, PCBs and the BOM! if there is anything I can make do to get the layout better - more then happy to! First port in the community and hope, not the last one. Highly appreciate everyone's time!

I built a little sub amp from a mono TPA3116D2 and a sub controller based around NE5532 op amps all in separate enclosures. The amp is powered by a 19VDC brick and the controller by 7812/7912 powered by a 12VAC wall wart. Since it works well, eventually I'd like to put both of those in a single case and power it from the 19VDC brick.

The amp would of course use the 19VDC supply but would also like to power the controller from this as well.

I can use a TLE2426 to obtain split rails or a op amp supply that was derived from a Silicon Chip article that I've used a couple of times (see schematic but disregard the voltages) to power the controller from the 19VDC supply. There's also ESP P43 but Rod states it should not be used on a shared supply.

Would there be any strange interactions using the supply for both or are there other alternatives?

In good nick, UK/Europe, please.

Hi everyone around,
Can someone help me to find /buy/ two pcs of the mentioned transistors ?
Thanks in advance,
Ignat

[fixed] ONKYO TX-8511 relays problem

i have this amp (receiver) now for 20 years maybe more. it is a great piece of technology and sounds nice.


i had to change the 2 relays now a couple of times because of a no sound issue (work-arounded by turning up the volume really loud where it started to play and then lowering the volume again).


the problem is that the replacement relays work fine for only 1-2y and then they brake again.


QUESTION: would it be a good idea to try to short connect the circuit handled normally by the relays. did anyone try? i have had it with buying replacement parts and disassembling the amp all the time.

Bored in quarantine.

What are some of your personal favorite tube audio amp designs that utilize two or more tubes in a parallel configuration, as opposed to a conventional SE or PP, or parallel combinations complemented by an SE or PP stage?

I have been skirting around the webs for inspiration but have come up dry.

Shoot.

Hi there,
I bought a nice mid-woofers that have manufacture provided box volume and tube measurements. I would like to try to build my boxes with passive radiators instead a tube. My only question is should I keep the same internal volume when use those passive radiators?

I’m basically new to oscilloscopes….well I have used an old one like 10+ years ago for very basic stuff…. But yeh basically I’m new haha
I was thinking of getting an oscilloscope preferable a portable one a module type to plug into a pc, phone, or even a small hand held would be good as I do repairs at home also so portable would be great!!! I can repair most things without an oscilloscope but sometimes you just need one for in-depth faults etc.... I repair kind of everything (that I can… I’m no pro haha still learning; everyone is!!) but mainly audio equipment.
It maybe a stupid thought but one like this would be a dream!! Looks too good to be true probably cheap and nasty with basic specs haha 😱
I haven’t done much research yet as I thought to post this first to eliminate a lot of branches if someone can steer me in the right direction.

Any suggestions on which way to go? A good allrounder?

Hi,

I am looking for a few people to beta-test the vacuum tube modeling software I wrote (for my own use), to iron out bugs before I do a public code release. Basically, it can build Spice-compatible models and do simple bias point/signal analysis calculations from the traced tube data (either from datasheet curves or obtained elsewhere). See attached screenshots for examples...

It is developed on Unix platform, but as it is written in Tcl/C should be portable to Windows (any takers?). Documentation is non-existant at the moment.

If interested, email me at frolov@cita.utoronto.ca. Replies might be slow (sorry...).

Looking to sell my SB Acoustics Ara cabinets in satin white. Cabinets are sitting in their box untouched at the moment.
Selling because delivery of the cabinets took 3 months and in the meantime my plans have changed.

The cabinets come with the bass reflex port and insert nuts for drivers installed. The following parts are also included:

• Hex socket screws 4x20mm (for drivers)
• Countersunk screws 4x20mm (for terminal plate)
• Wood screws 4x16mm (for crossover)
• Stainless steel terminal plate
• Binding posts (black and red)
• Seal gasket for terminal plate
• Name plate
• Grills for tweeters and woofers
• Damping material

Looking for 450AUD/275USD + shipping

Hi!

For my next project I'm playing with the idea to make a bullet-type tweeter. The tweeter I bought (SB19-ST from SB accoustics) comes attached to a mounting plate but it seems to be easy to take that small 'baffle' of.

Are there any reasons not to do that sound-quality wise?

Kind regards,

Reinhout

I own some great cable but they are stiff, almost like TV antenna cables, it can be a bit annoying when trying to use it to measure on projects. Is there a cable >500Mhz that is flexible and maybe thin? Of cause do I not mind if the cable can be used for much higher frequencies is double shielded and so on, but that would also make the cable less to my wishes, do I think🙂

Godo day all.

I just built the APEX speaker protect circuits for my AMP CAMP AMP, but Im struggling to figure out the connections for these circuits. Could someone please advise on a schematic for it please. Image below is what I have built





Thanx for the absolutely great site.

Regards
Cedric

Hi,

i had some pcbs left, each 12€ + 1€ packaging + your shipping option, please only EU (customs declaration makes no fun!).
Cheapest way would be a padded envelope, that should be the lowest costs.


(Sorry the picture is a little distorted, please click on it)

Hi,
I'm going to power a tube with a heater current rating of 0.8 A, 6.3V.
The transformer I am considering has a secondary current rating of 2A no CT.
I plan to use a bridge rectifier and RC filter to produce DC at 6.3V.

Will the 2A 6.3 VDC transformer be sufficent to power the filament?
I have seen somewhere that the transformer current rating should be 1.8 times the load current when using a bridge.

I normally use a full wave for filaments but no CT in this case.

Hi folks,

I'm working on my second DAC project, and I've run into a problem working with the SRC4392. Maybe someone here has some insight.

I'm sending I2S from a Raspberry Pi into the Port B serial port, but it only works with 24-bit data and there doesn't appear to be a register option for 16-bit I2S. I could tell Volumio to upsample to 24-bit, but that kinda defeats the purpose of the SRC. Port B is set up as a slave.

Background:
My first DAC was a simple PCM5142 driven via I2S from a Raspberry Pi. It worked well and sounded surprisingly good. It is compatible with the Allo Piano DAC driver, so I used that.

https://www.diyaudio.com/forums/digital-line-level/313760-starting-simple-dac.html

The PCM5142 seems to be happy receiving 16- or 24-bit data at any speed from 44.1 to 192 , but the SRC4392 isn't so accommodating.

The new one has an SRC4392 between the RPi and the PCM5142, with the DAC driven at 192kHz 24-bit by a better clock. I'm programming the 4392 from an Arduino Uno, thinking I might eventually add other inputs to the 4392 and make it a digital pre.

The format options for Port B (Register 05) are:

24 bit Left Justified
24 bit I2S - this works perfectly for 24-bit files
16, 18, 20, or 24 bit right justified

I thought 24-bit I2S would work with different data lengths, since it's MSB first. But no.

Has anyone made 16-bit work with the SRC4392 serial ports?

BTW, this forum is an amazing resource and a great community!

Thanks,
Peter

Sorry, I don't know if this is the right place to post it but I had to make a pick :-/

Alltime good guy and DIY speaker Guru who passed away two weeks ago after a kidney operation and then somehow contracting Corona... :-/

https://www.washingtonpost.com/nati...GuZeyg7BgS5Na6fd0SSC25vTTSiVFEWZDBjD4XsVIuoSI

Anyone have knowledge on this amp?
Yesterday there was 77v dc on the output but I applied a 4 ohm speaker and the voltage went away and it played music fine. Then I tapped the middle of the amp and it started to have static and buzz come out of the speaker. I instantly removed power and opened it up
There was a swollen cap 80v2200uf cap near the rca input that I replaced.
So when powered up with no load on the output there is 55v dc. When I applied a 4 ohm speaker it drops to 2v roughly.
There is 2 amps idle current with or without the load applied.
Also a little side note, without remote the protection light if faintly lit.

DIY FirstWatt Pass F5 power amplifier

Unit works perfectly

Build notes:
- DIY Audio Deluxe 4U Chassis w/ aluminum handles
- Primrose audio/SumR 500VA transformer
- Belden 89259 PTFE Coax cable for input wiring
- 16AWG silver-plated copper wiring throughout
- CMC gold-plated binding posts
- United Chemicon KMH 60,000uF, 35V power supply bank.
- Blue LED's on boards and power supply
- Mostly built to spec, except oversized 500VA transformer

Asking $800 shipped in the US.
Please consider that the DIY chassis + transformer cost $580 alone.

P.S life changes require full downsize of my system and projects, all of which I will be selling.