During the days I studied Physics, the frequency standard was C as 256 Hz.
There was a standard book called Clarks Table, which referenced it.
I even had some tuning forks of 256 Hz (C)
Now we refer A as 440 Hz (or 220 Hz), which makes C as 261.63 Hz.
When was the change made and why?
Can anyone point to some explanation or a reference?
Thank you.
Regards.

Have a Russco Studio Pro Model B coming my way. Think I have sourced all the parts that I need to do the rebuilding but need a plinth. I'm good with metal work, machining but have no wood working tools or room to do that.

So if anyone has a stalled project hiding in their basement and wants to sell off a plinth, let me know.

I'll also be looking for a 12" tonearm for it.

Thanks


BillWojo

I greet everyone
two questions, the first concerns capacitors. which one is best to use in electronic crossover filters currently.
second question what to choose between AD823 and OPA2132 always for electronic cross, also at the same price there is something better?
Hello everybody

Hi,

How does a shot gun microphone produce a narrow directional behaviour?
In what frequency is the narrow directivity valid as compared to the dimensions of the slots?

Please see the directivity plot at The Lobar/Shotgun Microphone Polar Pattern (With Mic Examples) – My New Microphone.

What phase relationship between the slots gets me a narrow focussed beam?
Please note that I am using the term beam as if its a speaker and not a mic. But I think its the same thing, in case of mic, of course there is no beam but its the ability of picking up sounds more from a particular direction.

Thanks and Regards,
WA

I see a lot of images of builds with sharp 90-degree bends of the internal wiring. It looks great, but is this bad practice from a technical point of view?

I'm not suggesting the electrons are going to have trouble turning the corner, more than you are deforming, if not damaging the wire and jacket.

Here is an image of what I am talking about. I know it will work, but would you be better off with a gentle curve?

Rest In Peace Jim Steinman.

"And if life is just a highway, then the soul is just a car"

Jim Steinman, hitmaker for Meat Loaf and Celine Dion, dies at 73 | Music | The Guardian

what new model can i use to replace the tweeters of these old ACOUSTIC RESEARCH AR15?

Replaced an old resistor yesterday that I suspected might be part of an oscillation issue I'm trying to track down (it wasn't). As part of it, I measured its inductance, and the inductance of a couple of replacement parts. I was quite surprised:

At 10Khz:

Old carbon comp, 200ohm, 0.5W: 200nH
Metal film, 220ohm, 1W: 220nH
Metal film, 220ohm, 0.6W: 670nH



Why this huge difference? The inductance (in this case), seems proportional to the physical size of the resistor. Is that a coincidence? Is there any general rule of thumb here, and are there any scenarios where it matters enough to be aware of?

Hi everyone,

I year or so ago I bought a Linn Wankonda with a wonky PSU. Apparently the seller has experienced a power surge and blew up his PSU (this he did not tell me, but in researching the issue I discovered a thread on another board where he was seeking advice on repairing the unit).

Anyhow, it looks like he replaced 2 FETs but there are a number of burnt SMD resistors. I have looked high and low for a schematic for this PSU but cannot find one. Because the resistors are burned (and open) I cannot read their values. Anybody know where I might source a schematic? Any other adivice on how to go about figuring out the resistor values would also be greatly apreciated.

Dave

is the two output modules in the crown k2 amp is identical ??

hi i looking for inner sleeves- the type you get sometimes printed on - stiff thin card- no hole- can anyone help


the flappy anti static ones i really cannot get on with

PEAK DCA75 in perfect working order fully boxed with all accessories.

£85 free shipping UK. EU £10

**ONE** unit for sale. Brand new in box, never used. One of the best sounding ribbon tweeters ever. Plus one brand new replacement diaphragm, never used.

$500 for both OBO.

Manufacturer RAAL
Tweeter Type Aluminum Ribbon Tweeter with Amorphous C-core Transfo
Ribbon Surface 21cm2
Impedance 8 ohms
Power Handling (RMS) 200 W
Frequency Response 500 – 100000 Hz
Sensitivity 95 dB

Hello Diy Audio members.

I just recently start a new company called www.proaudioparts.nl
This webshop is specialised in rare , obscure and hard to find and recent parts for pro audio equipment. mainly Harman pro audio like Crown , JBL, Soundcraft etc.

Have a look and maybe you find what you were looking for for a long time.
We ship worldwide.
You can view the site in dutch, englisch and german

please note the site is still under construction so be gentle on me if you find a mistake 🙂

Hello, I am working on a board and am not sure what type of component this is? Think it may be a capacitor of some type but not sure?😕

New user from Netherlands here, greetings to all🙂

Have always enjoyed music, but never got round to getting a high quality setup at home. Interested in building my own, great to find a place where there seem to be so many helpful people willing to share their knowledge and experience.

First order of business will be:
- Obtain cheap DAC/Mic interface, measurement mic, replace Volumio RPi3 with RPi4 for BruteFir capabilities -> practice measuring, create filters in REW, try to squeeze max performance out of current old, boomy, muddy sounding setup.

In the (semi) long run I'd like to design and build:
- 3-way TL for our living room
- 2-way for 2.1 setup for our small but cozy (one couch for max 3 people) home cinema.

These will be active (with hypex fusion).

Currently reading:
- this site 🙂
- Murphy, J.L. - Introduction to Loudspeaker Design;
- Weems, D.B. - Designing, Building and Testing your own speaker system;
- MJK articles (including the TL alignment one)

Also happily modeling away in Hornresp, figuring out what variable influences what (loudspeaker wizard is excellent for this) and trying different drivers in enclosures modeled after results from MJK alignment paper.

What I look forward to:
- Learning, discovering;
- Having top-sounding system that is custom built and designed for our living spaces and having the satisfaction that I did it.

What I have resigned myself to:
- DIY is expensive. I doubt there is anything to gain in parts expenses (wholesale B2B prices vs individual purchase of drivers, and DIY channel is maybe even B-stock?). And if there is anything to be gained from cost perspective, it's a still a fallacy due to time investment.

What I find challenging:
- Directivity. For a larger room with less than ideal speaker placement due to WAF and no particular intended sweet-spot, is wide dispersion prefered? This would mean dome mid range, no? Because wider diameter cone mid range = more beaming + waveguided tweeter to match = a narrower angles before response starts to drop.
- choosing a mid for a three way taking the above into consideration.

I replaced my 2005 Toyota RAV4 OEM stereo with an aftermarket touchscreen unit. The wires were connected using shrink wrap with built-in solder, and the connections to the harnesses are nice and snug.
The speakers now crackle only when I turn on the car. Any tips to fix this that might avoid having to install new hardware to delay the surge of power to the amp when starting up?

Hello All,

I have an AR turntable from the mid ‘80s. I think it is an XE model, with Sumiko Premier MMT tone arm and currently a Sumiko Blue Point EVO III cartridge. Over the years it has undergone quite a bit of modification. Merrill mods, including springs with foam damping, dampening material added to the sub chassis, and new motor and bearing oil. The motor did not last long, and in 2004 was replaced with an Origin Live DC motor and controller, with a new pulley and belt.

It has had infrequent use for the last 10 years, but I am considering using it to transfer some of my favorite LPs to a digital format. So, I recently did a little cleanup and maintenance, and the unit seems in reasonably good condition. I recently came across a great free program for measuring wow and flutter ( A.N.T. Audio :: Welcome :: Library ) Using Analogue Productions Test LP I measured W&F for this turntable. The original specification was for 0.04% DIN weighted, the current measurement indicated 0.0587%rms, also DIN weighted, which seems OK for a turntable of this vintage. But when I look at the speed variation (see attachment) I am having second thoughts.

So, the question is, do you think I can improve on the speed stability? And if so, what would you recommend?

Cheers,

ceulrich

I recently built the 12p-sized frugal horn and removed the drivers, hook up wire, and terminal cups from these cabinets. The 12p sounds great in this cabinet, it was just time to build something new and I had the room for the larger FH-type enclosure. Rather than store them (they're big), I'd like to see them go to someone who can enjoy them.

The top and baffle are a butcher block and the sides/rear are a stained plywood. There's a little checking here and there and the cabinets could use a quick sand and fresh coat of poly, but they're structurally rock solid.

You can find approximate dimensions here: http://www.frugal-phile.com/boxlib/pensils/Pensil-Series-set-100711.pdf

Would trade for tubes, amplifier parts, woodworking tools (power or hand tools), bench equipment (power supplies, etc). Asking $50 to sell. They are located near Milwaukee.

For Sale:

JLH High power PCB stuffed. JLH-2005 version.

I bought these years ago from member here on DIYAudio site and used this in an amp for a while before switching amp to a ESP P101 amp.

I put terminal blocks on the output devices so I could try out other transistors. Comes with (8) J4315 output devices.

I will look around for the Schematic...worked great when I last used it about 8 years ago...

How $100 shipped CONUS?

please make an offer if you have spares ...

thx

Hi all !
I tried to measure the voltage of the dats3 measurment sweep and im not sure if my voltmeter is overshooting cause the sweep is so short.


did/can anyone try to measure the voltage and can confirm my measurements ?
here are my results:


10dBu=2,415 Volt
8dBu=1,921 Volt
3dBu=1,079 Volt
2dBu=0,957 Volt
-5dBu=0,424 Volt

I've ordered these two boards to make an EAR 834 clone but I can't work out from the PSU board whether it's designed to produce 6.3 or 12.6v heater voltage. The seller isn't responding and I want to get a transformer ordered. Can anyone shed any light on this please?

1set Gold Stereo tube Pre-amp MM RIAA EAR834 phono 12AX7/ECC83 Assembled Board | eBay

1set Gold plated tube preamplifier HVDC285V Powr supply PCB assembled | eBay

Hello there,

Clearly I do not know what I am doing, and I probably shouldn't even be trying to build a Franken Amp from what seems like a mish mash of parts, but here goes,

Main amp board,

E3 Audio TPA3255 2ch PurePath™ Ultra-HD Class D Audio Amplifier

TPA3255-2CH-260W | 3e Audio

Power supply,

Connex Electronic SMPS300RS 300 watt (400 watt peak) 36v, +-12 volt power supply

SMPS300RS | Connex Electronic

Preamp with single ended input,

WEILIANG AUDIO preamplifier board with shield,

WEILIANG AUDIO preamplifier board with shield|breeze audio|lm317 lm337preamplifier audio - AliExpress

Single ended input to balanced converter board,

Unbalanced to Balanced Output Stereo Converter Board Low distortion DRV134PA x2

Unbalanced to Balanced Output Stereo Converter Board Low distortion DRV134PA x2|x2 housing|board to board rf connectorboard msi - AliExpress

It is my understanding that the E3 Audio EAUMT-0260-2-B TPA3255-2CH-260W prefers to be driven with differential input to get the most out of it, that is why I have included the last item.

Perhaps I don't need this last item, and the amp should be driven single ended, what do you think?

Am I barking up the wrong tree here, or does this look like it would work/be a good fit of components?

Thank you,

David

When looking at specs, what should I look for? Flat response? What can the t/s tell?

Why should I pay more for a driver?

A few opinions would be appreciated or a link to an existing resource.

Folks, I assembled the Pass DIY class A kit, building two units each used in balanced mode. I'd really like to build a Pass designed preamp but require balanced inputs and outputs. Based on my somewhat simplistic understanding of balanced operation I figure one could use two stereo preamps with the two channels used for the Positive and Negative signals with a common gnd. This would be somewhat cumbersome to operate but no different from two mono preamps.
My apologies if this issue has been addressed before and please feel free to inform me of my ignorance.
Regards, steve

Hello,
Need to replace the input stage transistors (BC182L) due to some damage during my recent move.
I'm looking at BC550C as it has a much lower noise figure (I suppose that is a good thing).
Can someone advise if the BC550C can be a direct replacement for the BC182L?
Both are TO-92 with different legs orientations, but that's not a big deal.

Many thanks.

The specs are:

BC182L:
Collector-Emitter Voltage: 50 V
Collector-Base Voltage: 60 V
Emitter-Base Voltage: 6 V
Collector Current: 0.1 A
Collector Dissipation - 0.35 W
DC Current Gain (hfe) - 120 to 500
Transition Frequency - 150 MHz
Noise Figure - 10 dB

BC550C
Collector-Emitter Voltage: 45 V
Collector-Base Voltage: 50 V
Emitter-Base Voltage: 5 V
Collector Current: 0.1 A
Collector Dissipation - 0.5 W
DC Current Gain (hfe) - 110 to 800
Transition Frequency - 150 MHz
Noise Figure - 4 dB

Hi, this is Donna from PCB ONLINE LIMITED, is there anyone who tells me that my post has the possibility to be read?

register PCBONLINE, invite code write ac, you'll get a cute customer service provider from Shenzhen China and satisfied PCB purchasing experience.😱

user management

This is probably a really stupid question but I'm paranoid and just wanted to make sure. Someone in my family rested one of my raw woofers with the rubber surround touching the ground. I'm not sure how long it's been like that.

I picked it up today and it looks fine other than the surround looks a tiny bit flat, but it seems like it's beginning to go back to it's original shape. Should I be concerned? Was going to use this in a project.

Does anyone have a suggestion for making simple, but elegant rotary audio dial scales, - bass - treble, volume, balance, rotary switch selector scales etc. I need to be able to select start & finish points, number of ticks, & appropriate number marks etc.

The idea then is to simply copy & paste them into "Word or Paint" programs & print them out after adding other labelling etc.

I have done this successfully before but not with dial scales. Once printed, they can be laminated & paisted onto a panel with quite good results. (KISS principle applies !)

I don't want to have to spend hours learning a complicated CAD program.

I'm asking this because in Google many articles seem to use current limiting and regulating interchangeably, so I'm confused.

First question... Are these two assumptions correct?

1. A current limiter sets a current target value, if the load resistance tries to draw more current it is stopped at that limit, but it can draw any current less and the limiter basically falls out of play.

2. A current regulator sets a current target value, if the load tries to draw more it is stopped at that limit just like a limiter. but ALSO if the load resistance tries to draw less current the current regulator forces the load to draw more current by raising the voltage.

Second question... When I wire up an LM317 with a resistor between ADJ and VO and put that in series as Vcc - Vi -Vo - load am I getting a current limiter or a current regulator?

I need a current limiter not a current regulator. Can a simple IC Regulator be used as a current limiter so that it only comes into action if the current gets too high and ignores a low current. (assuming the above LM317 isn't already a limiter)

The year 2018 is almost over. I promised myself that I would do another amplifier - a prototype. I have material in stock.
I plan to be finished by the end of the next week.

scheme:

Not quite an audiophile level amplifier, but at only $350 it’s a real bargain for some less demanding purposes. 75 watts per channel into 8 ohms (20-20,000 Hz) at 0.08% THD, with 2 channels driven. Plus lots of features typically found in AVRs that usually aren't in stereo amps.

BestBuy, Crutchfield, etc., are all selling it at the normal retail price of $549. Some Costco stores carry it, some don’t, but right now it’s also available on line for Costco members at $350 including free shipping.

I just ordered one and will still have to find out how it sounds. However, with a 60 day return policy there is not much of a risk.

If you are interested it’s best to jump on the deal now, since it seems to come and go from time to time.

I have a friend that may consider an used SA/3 for his Snell C speakers. Those should be 4 ohm speakers and a bit hard to drive. How much power can a SA/3 put into such speakers?

Is there any information somewhere on how the bias concept is and how they are rated in 4 ohm.

There are rated 50W class A in 8 ohm. It is printed on the front and they seems to have relative high current ratings. 16A continuous and 80A peak?
It is a bit more than ACA.....which I will bring for the next visit just to have some fun.....

Stasis are single ended amps?

Hi All,

I noticed a previous thread on an Audiosource Amp 300 that was sparking so I thought I would post about mine, it's been used for many years as a multi zone amp for 5 different zones going through a Russound Pro-6. What I'm seeing now is that the amp will run for a while but the audio is a bit distorted and lacks bass in the zone speakers but will eventually shut off on 1 channel when getting heated up and then the other. The Amp light is still Blue, and when I shut off the amp, then turn it on it will begin running again for a shorter and shorter periods before going into protection again but not showing a red light, still just the blue light. I took off the top and did a visual inspection, and dont see any burnt mosfets/resistors/caps in the power board, and don't see anything visibly wrong on the signal side either. Can anyone give me a starting point for trouble shooting and a direction to head to solve this, as I don't think it will be worth sending it to a repair shop, that bill would be more than buying the amp used on Ebay LOL help! While it does look a little dark around IC01 and IC02 (and I have seen on some other forums this seems to be a common problem) the board isn't burnt or anything. Anyone having some simple trouble shooting tips would be greatly appreciated as it seems like if that's the issue that's a pretty simple swap out.

Looks like IC01 says AUK 526 s7815 PI and IC02 says AUK 444 7915 PI is there a simple trouble shoot? or should I make a play to replace both the ICs and maybe the resistors in front of them for safety? R02 and R03 ..... The Caps don't look bulged at the top to me.

I am looking to make a transmission line 1/4 wavelength folded subwoofer that would use three drivers. Standard theory that i have been using has been the port mouth area that defines the design is the same as a the drivers cone area (SD). So for a two or three driver design do I uses the SD of one driver to define the area of the mouth/port or do i use total SD of all drivers in the array?

I googled this a lot and i could not find a definitive answer. Thanks in advance.

Amp powers up and plays fine .

The problem with the amp is it will play fine then protect them play fone for a day or 2 then protect .

It will sometimes play/protection over and over again .

The guy stated that the amp has been back to Orion 3 times for the issue but they said the amp works correctly .

I can’t get the amp to do this either .

I noticed if I hook the amp up with no rca jacks just power ground remote and speaker I can hear a faint ticking through the test sub .

When I hook the rca jacks up to the amp I get a loud humming through the test sub .

I also noticed I have half a volt of dc measured directly across the speaker terminals and also half half a volt of dc on the rca shield grounds .

Any ideas ?

Hello!

I´m looking for a replacement diaphragm with voice coil for my Russian LOMO 1A22 high frequency drivers. So far no luck, not even original piece.
So.. my idea was to find a modern driver with the same voice coil diameter, but again no luck. Can you recommend where I could find something for these drivers? The magnetic cap is exactly 39.9 - 40.1mm wide.

I have a few of these drivers with completely burnt coil and holes in diaphragms, these cannot be restored in any way.

Thanks!

Looking to buy one Resolute Audio RA2500/RA0105 board. if anyone has one for sale dead or alive, please let me know.


Zc

Hi Guys,

got a strange 4 band diode and just wanted to know the value, if anyone can help that would be great!

Hello all

In search of a schematic for the item listed above - I believe it's 70's era -turntable AM/FM receiver unit. Wired for 240 sold in Australia from Japan. The power amp section is 4 Toshiba 2SC490 (two per side). It arrived with one side down in volume and a bad hum. Recapped the power supply but it didn't fix the problems. While checking voltages on one of the transistors in the final audio power stage my hand slipped and it must have shorted (?) and started smoking resistors (2 1ohm 1 watt on emitters on audio LEFT). Each time the power was then applied the two resistors would smoke after a few seconds. I removed the transistors from that side and I'm waiting on replacements, but as is the other side (RIGHT) works fine. Steep learning curve as I'm more of a tube guy but checking if anyone A) has access to schematic or one close from that era and B) ever heard of anything like that happening as a result of a momentary short (to ground I'm assuming). Thanks in advance!!

Hi. I CAN HAZ CRITIQ PLZ?

I have a large vaulted room. 19x40 with a vaulted ceiling reaching 15' at the peak. Due to WAF, I'm working with specific locations in the room where speakers can go. I have some Klipsch Cornwall I's in my room corners. My personal listening habits have me all over the room and I really don't spend much time in my Cornwalls' sweet spot. Omnidirectional speakers (or more accurately, radial speakers) are said to have a very large sweet spot. There are not very many available and they tend to be very expensive, especially for the larger models that would go well in my large space. So, DIY it is. I decided to build a very basic/inexpensive pair of omnis to get a little bit of an idea of how omnis could work in the room. I mounted Visaton BG20 full range drivers on top of a 30 liter sealed baltic birch box with 45 deg dispersion cones above. The driver spec sheet said fc 82 Hz QTC 0,96 so I figured I'd fill in below 80 Hz with My Hsu Subwoofer. I chose a sealed design because the ported spec is 50 liters.

Well, they sound a bit like toy speakers. Really very small. There seems to be a distinct lack of low-mid frequencies before the sub fills in. At the same time, I can tell that they have promise. If I can find the right driver(s) and the right cabinet construction, omnis really could work in the space. See pics. They're far away from the walls and have two large sweet areas on either side of the pair, which is perfect for the room.

I'm not sure how well executed these speakers are. They're my first. I'm wondering if the lack of low-mid frequencies comes from over-bracing them? Maybe the holes I put in the braces weren't large enough? Maybe I over-stuffed with sound attenuation material? See pics.

I think some marginal improvements might be had by rounding off the edges and sinking the speaker flange to make the top of the cone flush with the top of the cabinet. I could also do the same with the support rails along the edges of the cabinet top -- sink them down to make them flush as well.

Anyhoo, I need to decide whether to proceed with this experiment by getting some better drivers, and building a speaker that is more suited to the room. I'm assuming that would be a larger one. I like the idea of a full range speaker with a horn coming out the bottom. It seems very elegant, but I'm not opposed to a 2-way design with, say a tweeter on top of the cone with another mini cone on top of that like Morrison Audio or Duevel speakers and I could do an active crossover on my MiniDSP 2x4HD. I could even bi amp them to add to the fun.

So, what do you think? Some Lii Audio Drivers? Fostex? Lowther? A Voigt pipe of some kind? A folded horn? A straight one? Forget the whole thing and just use my Cornwalls?

Thanks for your critique!

In case you are wondering, the pig is a javelina.

Yesterday I was checking the setting of the trimpots on my ACA (which has been working fine for a few months now since I built it) and when I finished noticed that one channel had gone silent. All the wires and solder joints look and feel solid I fear I might have shorted something with the alligator clips of the multimeter. Most likely the neighboring pole of the MOSFET Q1.There is no apparent damage to anything. I also had connected a home made headphone adapter to the speaker outputs and noticed that it turned stereo into mono so it is also an alternative posibility that it (the headphone adapter) has an internal short and shorted the amp in turn.



Where do I begin troubleshooting this? If I burned out something and can anyone suggest the most likely candidate? The mosfet? I'm really pissed at myself.

Hi everyone, I want to make a purchase from a website located in Slovakia. Unfortunately they don´t ship outside their country. I´ve tried to contact them by email. No reply so far.

Is anyone from Slovakia wiling to help with purchase? Also maybe some feedback of the website.

I´m located in EU.

Thanks.

I need to understand what dual triode tube is best to use as a cathode follower. So if I had 5 tubes to pick from, which is best, a tiebreaker.

What characteristics of a tube might make tube "A" a better cathode follower than tube "B" or tube "C", etc.? In the context of a CF stage that follows a grounded cathode stage that then either drives a power tube stage or a line out.

Curious if anyone has a stash of Neo10's that are no longer needed. Any help or leads would be greatly appreciated.

Hello !
If anyone has the diagram from the Sony TA-V5 amplifier. I found the Sony TA-V7 but it differs a lot.
Thank you

Fisher STE-1200 Speakers - Crossovers Repair
Replacement:
Capacitors, Resistors, Wires

Seems odd that we don't have a Tuner section here at DiyAudio.

I remember a new FM discriminator being talked about in the late 1970s that involved an
Xor gate to generate pulses on the zero crossings of the FM signal. Pretty sure this was
the Schotz demod but I seem to read more about Schotz "noise reduction".
It was used in Proton, NAD, and perhaps a few others and had an inherent advantage
over other discriminators.

Anyone have a link to a better description of this FM discriminator?

Happy weekend everyone!

Just was having a sort of thought - maybe some of you seasoned folks can shed some light. I recently picked up a pair of these Aegirs, to see what all the fuss is about. I have to say, I was most impressed with two of them as monoblocks feeding my relatively inefficient (86db) speakers in a small room. It was a striking difference in quality and detail that I was surprised to notice.

After a moment's thought, I realized this was the first time I'd run a fully balanced setup DAC balanced out, to balanced pre, balanced out - to the Aegir's XLR inputs (only available when used as monoblocks.)

It stands to reason I'm not moving through all that many watts - though this is measurable. Previously I'd seen I was peaking on bass-heavy tracks around 12 watts peak. So I'm trying to better understand what might be bringing such a dramatic improvement in sound.

And, naturally, one begins to wonder, should I really build an Aleph J? Nothing like a DIYers mind to boot. I bring this up since at $800 for a single, it's tough to argue against it, but a pair of these at 1600 plus tax and postage, does get you into a different category expense-wise, and begs for some consideration.

The big win here, of course, is what I'm hearing so far, and for that I am thankful!

So, in my typical style I've decided to run before I can walk and design a (probably overcomplicated) differential output front end for a bridged amplifier (no idea what the back end will be, that'll come later). It seems alright-ish in the sim to my very inexperienced eyes, but hopefully you fine folk here can tell me how it'll explode if I ever build it.



(X1+X2) and (X3+X4) are ECF80s, with the triodes being used as an input buffer and the pentodes as a constant-ish current load for the shunt cascode. I realise I could probably get away without the buffer but I have the tubes already, the pentodes seem to work well as a CCS and the triodes were going spare.

(X5+X6) and (X7+X8) are ECC84s, paralleled for a higher current swing.




I was looking for enough gain to drive 30 watts into an 8 ohm load, and I've overshot a little but that's easy to dial back. The response to a 20khz square wave looks fairly nice. Is the slight gain mismatch (V32 is - out and V33 is + out) something I should worry about? I tried to make the amp stable while leaving the step response as good as possible, but should I roll off the higher frequencies more?



Running about 36dB of feedback, I had a fair old problem with instability but I think I've managed to rein it in. At the moment the gain margin is 11db with a phase margin of 54 degrees.

Hopefully you can let me know whether this is a viable design, or whether it's way overcomplicated. Any input is welcome, I'm a complete newbie.

Many thanks
Boulder

Any allnic h700 users on the forum ? Looking to possibly upgrade to this phono stage amp or audio research ref3 .

Amp came In with blown outputs and driver ic’s .

I noticed on the 47mh inductors the voltage jumps all over the place there is no steady voltage it will start at rail voltage then bounce down to 70 volts then back up and continue to cycle like this .

Any ideas on what might cause this ?

I hope you can help me.

Situation:
I have a Quad 66 Preamp model 2
Quad 66 series 2 SN: Preamp: 210938 (Series 2 Start with SN: 210600)
Processor and Display board is 1 BCP
Processor / Display driver board SN: I34601A

And a Tuner model 66

Issue:
The "Large" remote control no longer works with the preamplifier.
The “Large” remote control does work with the Tuner, search, Track (channels) etc.
It also does not work through the remote wire connection.

The pre-amplifier remains at its last setting, being CD input and at half volume.
The sound is normal/ good.

Now I have schematic for model 1 and not from model 2.

Question:
1_Could anyone help me to get the Model II schematics?

2_I measured some voltages,
IC 10 receives a voltage from pin3 + 7volt and on pin 12 -7volt.
IC 7 8 9 11 12 all have LM339 on pin 3 + 7volt but on pin 12 0volt.
According to the Model I schematics, all these chips should get LM339 +/- 7 volts.
Are these measurements correct, or is there an error in the power supply?

Regulators IC 4 and 5 give normal + and - 8 volts.

Any idea what could be wrong?

Thank you for your time.

Greetings, Joop

I am considering attempting to upgrade the balanced inputs/microphone preamp board on my Digidesign 003 Rack.

They are for channels 1-4 and are based upon TL074.

There is an existing "well known" and easy modification by Blacklion Audio which replaces the TL074 with OPA4134 and also upgrades to Nichicon FW capacitors. I might make my own version of the upgrade with Panasonic FM capacitors, Nichicon UES (green) and OPA4134.
Based upon the linked listening test I think the OPA4134 is a great choice especially with the feedback on Digi 003 racks that were upgraded: ULTIMATE OPAMP SHOOTOUT... Where you get to decide.



Before deciding I was wondering if there were any recommendations for suitable very high quality balanced preamplifier designs that I might consider.

In my box of available parts I have tested (distortion and noise) and verified OPA4134 and LM4562 along with various BC series low noise transistors as well as tested (in my 60 dB LNA) generic 2SB737 and original Rohm 2SD786. The generic 2SB737 appear to be good and are the lowest noise that I have tried so far at the input of my LNA.

The Digidesign 003 is pretty modular in the sense that the input board for channels 1-4 is separate from all the other boards and has nice 0.1" header connections for the balanced inputs and outputs for each channel. So it would be reasonable for me to design a new PCB. The input headers go to the balanced connectors on the back and the outputs go to the A/D/A board with the CS5361. Or I could go the easy route with just OPA4134 and Panasonic FM swaps.

Hi everyone,

I just (hopefully) finished the PCB layout for our LPUHP clone. The board hosts XLR input, RJ45 power-good/mute connections and speakON output connections and is intended to be used in this case: F 1048-160 KWL | BOPLA

Board setup is 4 layer with signal/GND on top, GND on layer 2, +/-18V on layers 3 and 4.

We added supply under/overvoltage monitoring which will be communicated back to our controller, a mute relay driven by the controller and also a DC servo.

The feedback for the noninverting branch of the difference amplifier (U202A) is taken directly from the GND-output pin of the speakON connector to make it ignore possible ground bounce in the groundplane induced by currents flowing towards the output connector.

I'm looking forward to any comments regarding routing and placement, especially regarding the last point mentioned.

Attached please find the schematic as PDF, copper layers 1-4 as PDF and 3d renderings.

Cheers, Jürgen

Edit: A small note about cooling: The PCB will be mounted up side down in the case with a aluminium plate abt. 3x93x100mm and a silicone pad under all the DPAK packages for heat transfer to the top side of the case.

Hello all, I’m in a “chicken egg” deal, do I build a firstwatt f6 amplifier, or a speaker kit?

Assuming the latter, I have a large room, 17’ x 20’ with uneven high ceilings (15 to 20ft). I listen to a wide spectrum of music, not too jacked up, but enough to experience the music.

Speaker plans/kits I have found interesting,
Frugal Horn xl
Sonido - Aion
Woden - not sure as they don’t post all of the dimensions HxWxD, I can only sell so much to the wife, but I need info.
Bass is only as important as the song requires to relay the message, the rap genre is excluded as I don’t listen to it.
I’ll admit, the drum solo in “hot for teacher” by Van Halen is a blast, but I can get over it 🤘.

Current system; emotiva xpa 5 amp, Marantz 7702 pre, definitive technology STS, rhythmik fv15hp sub.

Sound quality is my first priority.

I'm looking for service manuals or circuit diagrams to fault find 3 x 2606 & 3 x 2609 measuring amplifiers. They look new for their condition.



Noticed one 2609 has mini tubes? and the other two are solid state built.



Managed to get one 2609 working using Deoxit D5 lube spray on the push buttons. I'm thinking the second 2609 unit has a dud LM723CH (a round chip!) when compared to the working unit.


Yet to look at 2606 inside and they need repairs too.


Cheers,
1 Pascal=94dB

Hi. A friend and I have recently rebuilt the cabinets for some KEF CS5 speakers. We made router templates for the KEF B200G and KEF BD139B drives. The B200 are the rounded triangular type. I switched out the tweeter so there is also a template for a Scanspeak D2604/830000, which I guess is of less interest. If these are of use to anyone in the UK, they are yours for cost of the postage. Photos attached.

My 2005 Toyota RAV4 has 2 Key wires and a ground for SWC, while my new head unit with built in interface has one dedicated key wire.
I grounded the yellow wire and connected my car’s Key1 to the unit’s Key wire, leaving out the car’s key 2 wire which corresponds to the 5th “mode” button on my steering wheel.

Can I twist my car’s Key1&2 wires together and connect to the unit’s Key wire so that I can use that last missing button, or is that a bad idea?

Hello fellow DIY'ers,

After much research and a few bumps along the road, I've decided to create a new thread to centralize (but hopefully not duplicate) information about making your own DIY Record Cleaning Fluid(s) - abbreviated as RCF's below...

From my research, I can tell people are passionate about the topic, and report satisfaction with a wide variety of fluids and regimes. I readily acknoweldge I am not a purist, or even an audiophile... I just want my records to sound as good as they can within my limitations and also acknowledge my bias to spend less time cleaning, and more time listening, and spend as little money as I can doing both.

I invite diyAudio members to share their success stories, or link to a post that they find useful... think of this as an on-going brain-storming session...

I will post links to relevant threads to make it easier for readers to make up their own minds based on what others have done before...The first link below is what got me interested in researching this topic further:

• "My Version of an Ultrasonic Record Cleaner, a thread created by member BBFTX" "Post # 1420 by member RRushton": My version of an Ultrasonic Record Cleaner

• The AudioKarma thread referenced in the first link above: Record cleaning- you're doing it wrong! | Audiokarma Home Audio Stereo Discussion Forums

• 
  A (Very Long) Primer on Record Cleaning Fluids: A (Very Long) Primer on Record Cleaning Fluids | Steve Hoffman Music Forums

My next post will share where my research has led me so far, which is a Word document I found on the web, by the author of the AudioKarma thread referenced in the link above.

I have a Philips NOS E88CC valve - can it be used as straight swap for ECC83 ???????

Hello,
Yesterday I received a pair of speakers from a Mr. Radu Tarta. I purchased them from him through this site and could not be more pleased with the entire transaction. From the absolutely beautifully crafted speakers to his generous handling of shipping fees to how well these were packed for shipment. Radu is truly an artisan and a gentleman. I’m inspired by his example and would encourage anyone to look closely at what he has to offer. Be it speakers, amplifiers, preamps or any other offerings. I’m not given to undue praise but in this case it’s simply impossible to ignore the obvious care and attention to detail he brings to his work. This world of ours is a crazy mixed up place. Many times profit appears to be the most important factor especially it seems when it comes to audio equipment. We are all here, at least to some degree, seeking better value as well as the satisfaction of building something ourselves. Radu is a prime example of someone who cares deeply about his work and imho the best of what this community has to offer.
I’ve only recently returned to this group after several years away and buying these speakers from Radu has been a wonderful re-introduction. I’m looking forward to perhaps working with Radu again and to enjoying this wonderful community. And of course these fabulous sounding speakers.
My best to Radu and this group.

Is my first crossover design any good? And other Noob questions

Hello, i designed my first crossover today and wanted to know, what you think about it. Im using as midwoofer the tcp115 4ohm and as tweeter the ND16FA 6ohm

I hope this is the right place to ask, if not im sorry
The Crossoverdesign:

In later post

The Components:

In later post

Lastly i wanted to ask if im right with the impedance of 10 ohms
and if :this super cheap amp from ebay is any good and if not i would like to know, which amp i could use(preferably a cheap one)
I choose 100w for the amp because i heard you should double the rating of the w the speakers are rated for (i have no idea if this is true, is it?).
Thanks!

--------------- Not required any more, thanks for looking ----------------------

Do you have any parts languishing in your "to do" pile for an Aleph J?
Looking for PCB/Kit/Parts.

Also looking for MoFo parts.

Prefer UK location, otherwise any where else subject to postage costs etc

Let me know what you have.

Thanks.

What have people been using to adhere 1/2" wool felt to speaker interior panels? I used double sided carpet tape for the last build, seemed to work but I'm always open to other suggestions

One of the most fascinating resources I've ever come across. Each individual instrument is recorded with a total of 22 mics in an anechoic chamber, with the musicians wearing headphones and watching a video of a conductor for proper timing.
Watching an RTA with a mic in front of a speaker is pretty revelatory for seeing fundamentals and harmonics of each instrument without the influence of a room acoustic. Make sure you put the RTA on it's quickest setting(8khz FFT)and the mic as close as possible to the speaker(Within reason🙂)
I imagine that it's been posted on this forum before, but I couldn't find it with a basic search, so..

Anechoic recordings of symphonic music - Department of Media Technology

Hi, working on a project and need replacement replays. From online searching its a 8 pole double open and double closed?

The model is SZ-2104 24v.

I searched online and this came up:

MT2-C93419
TE Connectivity, 24V dc Coil Non-Latching Relay DPDT, 2A Switching Current PCB Mount, 2 Pole

is this correct type and a decent replacement? Thanks any advice appreciated.

There are several threads about vinyl cleaning, but vinyl inner sleeves are marginally mentioned. Let's discuss the various materials, which is preferred, which is to be avoided.
Sleeves could contain and release visible and invisible particles: debris, plasticizers. They could chemically or physically harm the LP. Although their purpose is to protect the vinyl during storage.
I met the following inner sleeve materials:

• Paper with a round cutout at the label
• Thick paper, internally smooth, with cover art
• Paper lined with (?) polyproplene
• Soft polyethylene
• Polypropylene (?) - some more thick, opaque, rustling plastic

It is annoying when you remove the LP from the cheap plastic sleeve, and it gets statically charged so that it immediately attracts dirt. I found this product:
Nagaoka 102 Anti-static Record Sleeves
Do you routinely replace the not-so-good inner sleeve to a better one? If so, right after purchasing, or after the first wet cleaning?

Hi All.

So i'm trying to fix up my Logitech z-2300 2.1 speaker setup that i bought ages ago because i have an affinity to it. I have an issue that i need to fix and am looking to get some input on it. The issue is as follow:

The rubber surround on one of the satellite speakers cracked at some point, i'm assuming from temperature or overuse. I ended up cutting out the cracked parts, but the speaker still crackles with the right notes/tones/volume. Can someone point me in the right direction of places to buy decent, good value rubber surrounds, the right adhesive to apply to it, and tips on the process?

Pair of Dayton RS270-8 10 inch woofers for sale. Excellent condition.Reduced $90 for the pair. see pics. Buyer to pay shipping.

I don't understand the difference between the two. Some manufacturers say their crossover topology is 1st order, but it actually is electrical 1st order but not acoustic. What's the difference? Does the electrical crossover not have a 6db slope? How does relate to phase?

Thanks for any help that can shed light on this.

Hello all,

Maybe a stupide question, answered many times.
But i can’t find a answer that i understand 🙂

If i use a PC with USB to Dac, set output in PC to say 24/384.
Dac say 384 kHz when play music.
But the music i play is recorded in 16/44.1.
Is the pc doing upsamle then from 44.1khz to 384khz?

Reason for asking is that i think music sounds better in 384 vs 192 kHz.
Maybe just placebo..

BR// Daniel

Hello,

I'm trying to get ferrite or laminated audio inductors in the 50mH-2H range, ideally custom wound ones. In my search I found the following sites:

Finest Audio Inductors
Inductors
Inductors
EQUALIZER (EQ) INDUCTORS
Classic Audio Products, Inc.
https://cinemag.biz/inductors/inductors.php

Either there is no answer on my request, or they are out of business, or vendor does not have part in stock or cannot provide requested info (DCR of inductor they selling). Can anyone point to the reliable source of audio inductors, preferably custom ones?

Hi there,

I have a pair of Technics SL-1210 MK2 turntables. There is a huge database of mythology about how various add-ons created by various companies can improve the sound quality of these and I was wondering if anyone has any views or experiences on some of this stuff.

I can neither afford nor want the hassle of an external power source and I am already using a decent cartridge so the potential next step for me would be to consider a tone-arm upgrade. These are rather pricey. Moreover, there is a school of thought that suggests that the biggest problem of the Technics arm is the cheap quality wiring in and this has got me thinking that maybe I should try that first.

At first look, the idea sounds like poppycock to me...I am one of those people that make their own interconnects by braiding cheap and cheerful solid core wire and am convinced that it sounds as good as oxygen-free-cryogenically-treated-special-alloy wire in some-near-extinct-animal's-leather sheath. This having read a few things about the theory behind it and having listened (or rather not listened) to the difference between different cables.

Nevertheless, I always like to keep an open mind. So, running the fear of starting up another behemoth of a thread like the "do cables matter" one, can I please ask people's opinions on whether tone-arm wire quality really matters?

Thanks,
Nikos

Do you have any parts languishing in your "to do" pile for a AKSA Lender?
Looking for PCB/Kit/Parts.

Prefer UK location, otherwise any where else subject to postage costs etc

Let me know what you have.

Also looking for MoFo parts.

This tube preamplifier, Elekit TU-8500 seems like the best deal going for a quality tube preamplifier. Comes from Japan as opposed to China. Seems like Victor Kung offers great support. You can buy it as a kit to save a few dollars (under $600 depending on options).

Why not more discussion here and other forums?

Anyone have one that could offer a short review?

What are the alternatives that I'm missing?

Greetings,

I'm putting together an amp with 300V across the anode resistors. I read on Tubecad it is better to use multiple resistors than one.
"There is a voltage distortion mechanism in many resistors that is so small at low voltages that it is usually disregarded, but in a high voltage circuit, such as this one, the distortion becomes an issue. Using six resistors in series reduces the resistor distortion by six fold."

I'm ordering parts, and I must say I'd much rather use one big high power resistor than six smaller ones. Would it be much worse?

Thanks.


The Tube CAD Journal, Electrostatic Headphones

Hello everybody.

I have a 300B stereo tube amp.

For a few days when I turn on a channel it makes a loud clack, ploc, plop, like two seconds after turning it on.

When I switch the 300B valves sideways, the noise changes channels. Could the 300B be broken?