As can be seen, the nylon part is broken and wet with oil and cannot be reliably fixed.

I am looking to find an exact replacement.

Appears to be a 100K (probably audio taper) pot.

Can anyone recommend part numbers for a suitable replacement that will drop in?

This is a fantastic sounding Pair of EL84 Mono Blocks
They were Built by John Miller of Tomcat Audio
They use a pair of EL84 or Russian 6p14 and a single 12at7
Mundorf Power supply caps, Miflex copper input coupling caps
They are 22 watts in push pull. with Hammond Transformers
$950 local pickup in Huntersville,NC

Looking for a couple drivers, but would take up to 4. Thanks!

Hi all.
Im looking for plans to build from. Synergy tops for small to medium outside use. 130+db@1m(more is more), 90 degree horisontal would be nice and usable to 100ish Hz. For subs im planning a pair of Skhorn double 21”s. If somebody has the plans for these, id be gratefull for those also.

I know there are lots of builds around, but has anybody drawn any plans to build from?

Thanks

Searches confirm that this should be a SPST on-off switch but I didn't see the switch rating mentioned. What is recommended?

Hello,

I’m interested in purchasing a prebuilt sun audio SV300BE from Japan. However the unit is 100v and I need a 120v for operation in the United States. Is it possible to convert the 100v to 120v without a separate step up (step down?) converter?

Is this a matter of swapping and soldering transformer wires? Or are the transformers themselves different? According to the sun audio website there are 3 versions: 100v, 120v and 240v which you must specify before ordering the kit. So I assume it is a whole different transformer. I hope I’m wrong.

I get the basics but a debate on another thread regarding Sony SS-S9s has got me wondering about cabinet volume. Why does a driver need a certain cabinet volume and when does it need said volume?
They were discussing 2.5 systems which bring me back to an old question: A sub-woofer and woofer sharing the same air space in a ported cabinet. Some have suggested that all calculations be made on the mean value of the driver's T/S parameters - makes sense. But what happens at high power levels? When the woofer becomes affected by the sub's response to frequency it doesn't 'do'. Effectively offering passive radiation and robbing the port of input ?

Preciso do esquema desse mixer, ele tem vários problemas, é muito antigo e já passou por muita manutenção.

Hi, can you please school me on today's plethora of these power supplies.. ?
Looks like clones of the Tektronics from some years ago.

Noisy ? good regulation, tracking, V droop with pulsed/ fast rise time loads, etc. ?

I am going to need one soon enough, though the Voltage and Current are under what I would prefer.
Currently have a feeler out to a local PS repair shop for an adjustable dual 50V 10A, but I probably wont be able to afford it.
As a mid-choice lets say a 36 - 38V 5A, Dual tracking adjustable bench supply would be great.

thanks very much for your advice!

ISO F3 UMS.

Hi All

For sale:

3 x MAX3223CPP+ Analog Devices
3 x MAX3322EEUP+ Analog Device

4 x SI9110DJ Vishay - Siliconix
1 x UA741HC Fairchild

2 x SG3524N Texas Instruments
5 x LM2675M-5.0-NOPB Texas Instruments
5 x LM2675M-12-NOPB Texas Instruments
5 x LM2675N-ADJ-NOPB Texas Instruments

100 x 4608X-101-104LF Bourns

1 x ICL7107CPL+ Analog Devices
1 x ICL7117CQH-TD+ Analog Devices
1 x ICL7126CPL+ Analog Devices

1 x MAX232CPE+ Analog Devices
1 x MAX691CPE+ Analog Devices
1 x MAX791CPE+ Analog Devices

Please PM.

Regards,
VS

Excellent condition 103r. Unmodified.

Sounds and looks great. If you're into tinkering, there are many diy and commercial upgrades for it. I left it in its original configuration.

Comes with original box, test results. please see pictures.

$250/negotiable

Hello Guys,

A few days ago i bought a Sony TC-K770es deck. Apparently it has been serviced not long time ago. I noticed that when rewinding, after several seconds it starts forwarding itself without any reasons, and keeps on forwarding. It looks like someone presses the FF button when rewinding. Does anyone have any idea what the problem is?

Thank you in advance!

In the new issue of the German magazine Hobby Hifi (2-3/2023), mr Bernd Timmermanns offered an update to his Jericho horn, this time using the Dayton PS220-8 fullranger.
The measurements are promising. You can also see the effect of the correction filter. It looks like an interesting project.
The magazine has a 14 page detailed article including a step by step construction guide.

. .

I have a complete set of the recommended Sonicap Gen I poly caps (including recommended bypass caps) for building the Al Klappenburger Universal Crossover for Heritage series Klipsch speakers. If you are thinking of building that one very good crossover to service any of the Klipsch Heritage Series speakers, this is a huge first step. See images for the exact schematic and the caps you would be buying. $50 takes all.


Items sold: thank you.

I've just come across this concept and haven't seen any discussion of it or the theory involved. Apparently you "drive" the inner shield (somehow) to keep it at the same impedance as the source thereby eliminating any leakage current or capacitance seen by the source.

Any one provide any "light" or references on the subject? And how would you do this - what kind of driver and how should you CORRECTLY connect the cable on both ends. Make any sense to use in a preamp?

Hello,
I absolutely need data on the following transistors. SJ2517 / SJ2518
Does anyone have a data sheet, specifications and/or can tell me replacement types available from Distrelec, Mouser or others? Because MJ21193 / MJ21194 would fit (as claimed in another forum) I can only get them from Chinese dealers.
Thank you very much in advance and kind regards from Germany

What are some practical and inexpensive methods for determine the diameter of existing PCB holes?

I have several PCBs and I am thinking of fitting in terminals and posts designed for insertion and soldering.

Wondering if anyone has considered or performed surgery on a Tek 3012 type scope -- the "B" series had a floppy drive for capturing images, the "C" series went for USB.

There are FDD kits for various media from a number of sources -- USB and SD-RAM would be nice.

WTB a completed 2ndHG. Ship to Massachusetts.
What ya got?
rvb100 at comcast dot net

Sold

Transcendent Sound Masterpiece 300B preamp. Comes with a set of tubes that have around 100 hours on them. I used it in a secondary system that has moved to a home theater setup. The preamp sounds good to my ears. There is a slight hum that I can only notice if I turn off whatever is playing and put my ear 1-2" from the speakers (~88 db efficient). It never bothered me enough to chase it down.

Asking sold plus actual shipping charges

Ships in a box that is 21" x 18" x 13" from 54956

A pair of never used never mounted CHP70.2 khaki.
Boxed and new. Price 50 Eur
Pickup by your courier at my address zip 27047 Italy. Post rates for pick up from European destinations are Better than if i ship. Of course i can ship if you prefer but it might costs 25-30 Eur probably.

have an old trio w41 tube amp that just smoked up (old capacitor died) but one of the diodes melted but i cant find any info on it online
trying to find the equivalent or close enough to replace it
has FR1 green dot dollar sign on it (pic attached)
)also have schematic if that will help
cheers

Hi , guys , would be very grateful if you can help me to identify I/V opa place in this dac - there is 3x 2604AU op-amp ( green colour ) and
4x LME49720NA on the row
I wanted concentrate on the tube output - would guess that opa is for solid state output ? What would be the most effective sound wise opa upgrade - as I wanted to put Burson V6 for I/V place - could I get sonic benefit in other places ?

Regarding tube output - there is not enough plate voltage for 5670/396a/2c51c tubes to be used for optimum plate voltage - at the moment is around 77v - one option is to remove 150u 250v capacitor and voltage regulator L7806cv next to the tube and E13005 -2 transistor which could rise voltage to 120v ?
Very grateful if you can advice me . Val

Hello, I was over at Parts Express and saw these new Planar speaker drivers that are on Sale the model is GRS PT6816-8 8 inch Planar Slim Tweeters , their Frequency Response is 320 to 20,000hz , I am thinking of using 7 or 8 of them in a Line Array as Tweeters .... and maybe 7 or 8 of the GRS PT6825-8 8 inch Planar Mid//Tweeters as the Midranges which are on Sale too ....... I was wondering if the tweeters can be mounted close enough to each other to avoid any major Lobing issues? -


GRS PT6816-8 Tweeters
- https://www.parts-express.com/GRS-PT6816-8-8-Planar-Slim-Tweeter-8-Ohm-272-128

-


GRS PT6825-8 Tweeter/Midranges
- https://www.parts-express.com/GRS-PT6825-8-8-Planar-Mid-Tweeter-8-Ohm-272-126

-

I have 3 spare AD811 IV empty boards as described here:
https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-368#post-7451599

I have successfully built one:
https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-372#post-7483361
https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-372#post-7484982

I truly like the sound of this board with my Miro AD1862 DAC.

I would like to give away 3 spare empty boards (limited to 1 board per member) if it make sense for you to pay US$2 for regular letter mail for the board to be sent to you.
If you like to have tracking available, it would cost US$9 for the shipping as registered package.

Paypal as family and friends only please.

Hello,

Recently I built 4 of these amps and used them in a bridged configuration for a few months.
With these amps I mean only the output stage. To drive them you will need an adequate preamp able to deliver the entire voltage swing.

I tried both bridged and single ended and decided that I will remain with the se configuration meaning I will keep 2 amps and sell the other 2.


A pair was given away.

2nd pair is now sold.

I have an SU-A700 non MK2/ 3 with burned resistors R751, R752, R754 and R755. R753 and 756 have gotten hot as well but not burned like the others.

There is no sign of any other damage except for darkening of the board around these resistors.

As this amplifier uses bespoke Technics ICs and is rather difficult to get apart, requiring removal of the main ICs on the heatsink in order to access the solder side of the main board, can anybody with experience in this unit let me know if it is worth bothering with? I fear that as no other damage is visible, one of the ICs is to blame and I unfortunately can't power up the unit given the burned resistors.

Hi guys,
I have a dynaudio DM6A mkii monitor here to repair and I need service manual or schematic, can anyone help me? thank you! Maxime

For sale a Thel-Germany low noise Psu up tu 10A and 100V.
Verry little use and top condition. Iv used this for negative bias voltage supply on my EL34 tube amp. But you can use this also for other project. Price would be 40 euro plus shipping 8,90 euro inside EU. Payment paypal for friends.

What is the purpose of the jfet in the Feedback loop of U3-B Opamp and all the circuit circled in red. Diode D20 is conected to 20VAC from the Transformer.

I got the SPARK Houston MINI-1998.
However, in order to drive this amplifier, I have to supply power to the amplifier itself from a separate power supply unit.
The terminals on the power cable that supplies this power were unlike anything I had ever seen before.
I would like to know what this 4-pin, round terminal is and if it is possible to get the same one.
I would appreciate any help from you knowledgeable people.
Thank you in advance.

From Japan

Hi,
Just wondering if someone might happen to have a Service Manual or schematics for the MEGURO MN-446A Noise Meter please?
I have one of these units and its developed an internal noise fault that is leading to erratic readings.


The new owners of MEGURO DENKI, Japan, no longer carry any information for historic MEGRUO products.
Thanks in advance.
A.

I have a miniDSP FLEX 8 with DIRAC LIVE uploaded to make it a "ALL-IN-ONE" Solution for your setup.

NOTE: This price includes the Transferable Direct Live License as it is attached to this Flex 8 Serial Number.

It is a digital preamp / electronic crossover / the best speaker-room correction / Equalizer with FIR capabilities, hence its name "FLEX"

The Powerful DSP Room correction capability is in BOTH Frequency response correction AND to enable time / phase alignment.
It will align the drivers / subwoofers to enable a perfect phase / transient perfect wavefront as validated in REW (Perfect square-triangular impulse response)
With DIRAC Live engaged, the music just sounds right and I believe it's the "Time Coherency" component that makes the music sound dynamic like LIVE MUSIC

Remote with DIRAC / volume / input / mute and other functionality.
USB / Bluetooth / Coaxial / Toslink Digital inputs
8 Analog outputs via RCA
Bluetooth is 5.1 with LDAC with 24/96 capability
Dual ESS 8 Channel DAC IC's used in paired mode for even better SNR (>125 dB)

SOLD to Ferds for $599 USD

NOTE: I have revised my system and require only require 4 Analog Outputs, hence looking at miniDSP DDRC24 or FLEX (2x4 std.) with DIRAC Live currently

SOLD with included insured shipping for US Buyers
SOLD with included insured shipping for Canadian Buyers

Interac Payment for Canadian Buyers
SOLD Paypal Payment for Canadian / US Buyers

Unit is Audio Research SP10.

Until the unit has had ~20 minutes to warm up, I get intermittent noise out of the right channel that sounds similar to the sort of noise you get when your headphone mic is rubbing against your clothes, or wind is hitting a microphone. I can also cause the noise to happen directly by poking or gently pushing the first tube in the right channel of the phono stage. I have tried applying contact cleaner to the tube sockets.

I'm wondering if this is dirty sockets, old/failing tubes, or something else entirely?

I want to buy a minidsp, preferably with 6 channels or more, I may also be interested in another brand, pm your proposals, thank You.

Apologise for the click bait, but I thought this was worth sharing


Login to view embedded media
Excellent insight into how individual perception is the foundation of our hifi listening experience.

Hello! I'm new to this forum and was hoping to get some guidance and hopefully a more experienced perspective of where I've gotten in my plans.
I have a 2002 Ford Ranger with a 2 door extended cab. I've already installed an upgraded head unit and plan to move on from there. Yes, I will be doing a big 3 upgrade. Considering using a Mechman 370A alternator. I intend to use Siless Hybrid 3in1 200 mil sound deadening material on the floor, roof, doors, and walls.
Goal is a SQ focused build. Not completely ignore SPL, but SQ first.
I'm planning on using dual 6.5" speaker pods and installing Dayton Audio RS150P-8A wired in parallel for a 4Ohm load, using a bandpass first order crossover at 200Hz and 4kHz. The tweeters will be Dayton Audio AMTPOD-4 wired inverted, with a first order high pass at 7.5kHz. Not sure what I'm going to use for the rear channels. Considering PRV Audio 6MR250B-4 SLIM speakers for the rears, but can't seem to get XSim3D to cooperate when they're plugged in. For a sub, I'm planning on using a single Dayton Audio UM10-22 in a 17"x18"x7" (external dimensions) sealed box, deleting the fold down seat behind the drivers seat.

Now to avoid having to come up with passive crossovers, I'm intending to independently amplify the front woofers, rear speakers, tweeters, and sub using a Down4SoundJP77 mounted to the panel that runs along the back wall under the rear window. Yes, to avoid the complication of multiple amps, I'm planning using a single amp solution. That's probably my one reason for doing so.
Going by the appx .944 cubic ft interior volume (not accounting for volume the driver will take up), I'm looking at an F3 of ~30Hz and F10 of ~21.76Hz while peaking around 48hz(appx +4db), not accounting for cabin gain and never needing to set a subsonic filter as it should never hit XMax (hitting 15.933mm peak at 38.15Hz). This is assuming wiring in series for a 4Ohm load and full 500W RMS signal.


Here's the graph I was getting in XSim3D without the rear speaker, assuming 100W out of the amp, no PEQ, and filters mentioned above (sub low pass set to 200hz, again first order, all Butterworth).

If you have some constructive advice or pointers, please feel free to tell me. I'm not against doing a double baffle on the sub box, just didn't do it on the original design plan.

Edit: I apologize if this is in the wrong section.

Last year I put together 4 Nostromo speaker (Alpair 11MS) in the smaller of the three design sizes configured for amplifiers with relatively lower output impedance the the two larger configurations.

Two were sent to a nephew as a gift on completion of his bachelor's degree, and we kept two, which I have enjoyed very much. I decided to build another as a center channel for use with Schiit's newly released preamp, the SYN, which contains an active implementation of what first saw the light of day around 1970 as David Hafler's DynaQuad.

For this third Nostromo, I thougt I'd try a different approach to the chamfer on the back of the baffle around the driver. The cabs I built last year were chamfered with my router leaving bosses at the screw locations for the mounting screws to bite into. The ususal way of doing things.

This year, I cut out the fronts from my last chunk of 3/4" baltic birch, and then marked locations of the screws where I then drilled 1/2" holes from in the rebate area to the back.

The baffle is sitting on the back of the box, but is not attached. The sixth circle on the rebate is a router burn mark that cannot be felt, so will have no effect.

After that, I routed the chamfer all the way around the back, followed by gluing in five smooth dowels a bit more than 1" long.

I'll make sure the mounting surface is smooth for the gasket, drill the dowels for the mounting screws. The chamfer is about 7/16". I'll need another bit to get a deeper chamfer.

The result should let the driver breathe just a bit better, and I'll have longer screws biting into the wood over a greater length. That should allow more cycles should I want to remove the driver and replace it after making a modification or repair. I don't expect to hear a difference, or expect to have any "proof" of superior performance. Just thought it would be fun to do.

Skip

Hi there, I'm looking for two fostex 207e drivers, I have a Bob Brines cabinet waiting for a pair to fit in.
These I believe are discontinued but hopefully someone has a pair gathering dust!

Thanks.
Donald

Hi. I'm gonna need some guidance here. I'm trying to find the preferred resistors used by the man himself and PASS LABS.

I have tracked down the 3W part which sits on the output stage, this is the Panasonic ERG MOX resistor, but when it comes to the others, I am a bit lost, but I have have an alternative. I am thinking of Amtrans AMRT Carbon Film Resistors. Vishay mrs25 can also be an alternative.

Can someone jump in an comment ?

So I’ve been home and self quarantining for the past few with Covid in my dedicated two channel room….couldn‘t be without music as I convalesced. But of course, there’s a big screen in there and revisited the classics. First just stereo…..nope…..separation at 8ft between left and right was too distracting. Turned on PCM in for 5.1 and then deleted the center and surround output…..Better but not ideal. Grabbed a retired Polk center channel……one of the typical MMTMM things……..aweful!…..worse than either no center or phantom. Voices locked to the screen but only the screen and male voices sound like am radios…….nope.

Did some googling and came across the old Dynaco differential thing. So I tried it and forgot I had the phantom center set……..left a big hole in the soundstage and left and right imaging collapsed. Hmmmmmm. So instead I took the left positive and the right negative and BINGO……that did it! Dialogue returned to the screen and intelligibility was the best of the attempts. Voices now have weight with support from the left and right channels…….this setup will stay for theater use for sure.

Now this only likely works as the crappy center is terribly inefficient co to my mains at 4ohms and of course, for two channel I’ll just disconnect it and go back to Analog direct into my preamp.…..and a full large 3 way Center would probably be better……but for those that are challenged for space to fit a true center or the desire to add an ugly box to their room ( that’s me), then I count this little accidental experiment as a huge success.

Hi Folks,

Not sure if this is allowed but a Flex 8 w/Dirac Live just showed up on Canuckaudiomart if anyone is interested.

This is not me, and I have not tie in any way to the seller.

Just a public service message.

I'm in the brainstorming phase of a new speaker build which lead me to create an excel sheet with those accelleration factors including matching factor.
I thought i can share it to you.
Source of the Accelleration Factor:
Motor acceleration 'Γ' in moving coil loudspeakers

And here is the sheet

the prices are taken from soundimport , so you might get it cheaper somewhere.

Edit: i did filter it by the Sd value. so dont wonder why the manufacturers are mixed up

I must be getting old or stupid, or out of touch. I thought cd is cd, that is compact disk for two channel audio encoded in 16bit pcm at 44.1kHz sampling rate. At least that's what i learned at school.

I know that there were attempts in the past to improve the cd. I do have hdcd player, and lots of hdcd disks (compatible with normal cd player), which were 18bit, hence better. Many Joni Mitchel's cds were hdcd, i have most, and they do sound better, if you have player. Mr windows big gate killed the hdcd.

I never invested in DVD-audio format, since i hate how slow the dvd players are due to watermarking...loading, loading, loading, eff that.

Even Super Audio CD was big flop. Mixed at cd format, but not compatible with anything. Dead child.

Now i came accross this cd in my collection, it has too many stickers. Does not sound any better than average cd. So it has compact disk CD logo, SACD logo, Multi-ch Stereo logo, Hybrid multichannel 5.1 logo, and finally DSD Direct Stream Digital logo.
Only shiityy THX logo is missing, just kidding.

Is this the pinnacle of digital disk evolution?
What is DSD? Anyone have 5 ears to appreciate 5.1 channel? What's next?

I am rebuilding an AT-1000 MK lll tonearm. Disassembly was straight forward until I got to the bearing cups. They take a tiny U-shaped tool to unscrew and it seems impossible to find the right size. I tried taking two sewing needles and gluing them onto a small wooden stick, but the needles broke before the caps unscrewed. Does anyone have any suggestions?

What is your favorite tweeter or super tweeter in 2023 to use on the top of a Horn system 3 Way or more , 1 inch compression driver with small horns , Bullet tweeter , Ruban or AMT ?

Consider the impedance peaks one is port resonance and another woofer resonance in the impedance curve when loaded in the box. Now what happens if you absorb considerable like 80% of the woofer resonance which is second peak of the impedance graph.

First question is : Does it needs to be there? Secondly consider a magic absorber material is there to absorb the peak energy in the second peak frequency then would that be good? what are pros and cons of absorbing the resonant peak at the second peak? in the link provided for reference: http://archimago.blogspot.com/2019/08/measurements-speaker-impedance-part-2.html

This thread is a continuation of the EnABL Processes thread here:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=100399&perpage=25&pagenumber=1


This thread is for listening impressions and questions concerning applications. This is not to contain the technical side of things. Those posts will be deleted. The thread for that is here:

http://www.diyaudio.com/forums/showthread.php?s=&postid=1460032#post1460032

Dear community,

I have quite a tricky question. I am using five Retevis EAL002 throat mics to pick up breathing sounds for a collective experience. As I am using the Behringer UMC1820 for my sound installation I have soldered mono jacks with 3.5mm to the throat mics so I can plug them into my interface. Unfortunately something seems to be off, the voice being picked up is very low and it also creates a very high and loud noise. Also pressing "inst" and not pressing "pad" does not help. I guess I am in need of a preamp. I have looked a l ittle bit into DI boxes, for example the "DBX DI4 active four-channel Direct Box with line mixer". But I guess it's not really what I am looking for. I have no experience and knowledge about these devices therefore I was wondering if someone here has some better suggestions for preamps/di boxes. Thank you so much!

Best,
SonicDriver

hey people , does anyone know(and can tell me) the best book to learn form the beginning the art of audio amplifiers please??
thanks a lot

Watching this morning, Login to view embedded media
According to an interview in https://guitar.com/features/intervi...ic-confirms-plans-tube-georgia-factory-crisis

March, we will increase its offerings to include 12ax7, 12at7, 6L6, 6V6, el34, KT88, EL84, etc.,

I suggest all goto the contact page and thank them, and let them know what tubes you would want !

Hi!

Looking for a pair of 6ES8, matched if possible.

Thanks
Do

* SOLD * I have a Technics EPA 100 tonearm with badly worn top and bottom bearings. The left and right bearings aren't as bad but will need work. Its a long story but I ended up buying 2 EPA100s, both I was assured were working perfectly but wouldn't play a full LP when I got them. The second arm was disassembled by a Techie who tried to help, so its all in pieces. As a sweetener I will include all the bits except the mount, arm wand and counterweight from the second tonearm. I will keep them as spares for the arm I bought from Samurai. The headshell is not included and no cable either.
The arm lift has been removed and is at the side of the arm in the first picture. The arm clip is broken but the piece can be glued back on or replaced with an SL1200 clip. It was actually broken in front of me by the clown who I bought it from.

I am in Perth, Western Australia. Looking for offers. I don't expect Samurai prices but don't want to give it away either. I was quoted up to US$600 to refurbish.

The B1 is great, what an amazing buffer but what about having it offer some gain of its own?

What mods can I do to get some gain out of it?

First off, I am a complete newbie to electronics as well as audio engineering so please keep that in mind.
The first circuit is from: https://tataylino.com/guitar-preamplifier-circuit/. This is the guitar preamplifier.
The second circuit is from: https://www.ti.com/product/LM1875
1. Here is the preamplifier:
2. Here is the amplifier:

I would also like to know a few things. If they are able to be combined, what would power them? I was planning on powering the preamplifier circuit with a

9V DC Wall Power Adapter, but I have no idea how, once combined, to power the entire system. Any and all help would be greatly appreciated. ​

Hello everyone.
I new on this forum and i would like to ask if someone could help me with this chinese copy of korean board.
It's arrive with all power mosfets burned also 3525 was burned, i replaced all power transistor and IC and it start to power on, but after it start to have anomalies with a sound,( only half sinus wave is out) and something strange with a power supply.
There are some measure that i take maybe someone can understand whats going on with this amp.
Measurements from central GND. Dc supply on 13.1V. Measurements without driver board.
IC 3525: IC393
Pin1: 0 V Pin9: 5.20 V ---??? Pin1: 8.3 V
Pn 2: 4.73 V Pin10: 0.05 V Pin2: 2.4 V
Pin 3: 0.01 V Pin11: 3.7 V Pin3: 4.3 V
Pin 4: 0.47 V Pin 12: 0 Pin4: 0 V
Pin 5: 1.89 V Pin 13: 9.37 V Pin5: from 2.6V and growning up Why???
Pin 6: 3.40 V Pin 14: 3.7 V Pin6: 2.37 V
Pin 7: 1.82 V Pin 15: 9.37 V Pin7: 3.5 V
Pin 8: 4.50 V Pin 16: 4.73 V Pin8: 4.7V

Also i measured optocouplers and have some strange dates: (mesures were done between pin)

Ic 303 Ic304
1-2: 52V ??? 1-2: 1.3 V
3-4: 0.2V 3-4: 1.08 V
5-6: 5.6 V 5-6: 0.24 V
7-8: 4.8V 7-8: 4.7 V

I have tooked also measurements from driver connector (without driver board, central GND as point). Seems something wrong with negative rail.

Vnn: -109.2V ?? -15: -14.57
Drv: -109.2V ?? +15: +15.00

VPP: +129V ??

Also R330 is very hot and when i try to touch it with multemeters probe i start to hear some noise from power transformer ???

I hope someone can help with this issue.

I've got a Goodmans XO 950/5000-2 crossover, a midax, a trebax and two 12" 8 ohm RCA woofers from a 1960's console that I'm going to try building a speaker with.

I never could afford an appropriate Goodmans driver back when I bought the midax (got three) Trebax (got two) and crossover (got two) so they sat for several years until I got the RCA woofers a few years back and casually experimented with them.

I put the woofers in series for a 16 ohm load as the other drivers I believe are 16 ohms.

I do not have the attenuators that could be used with these.

The midax and trebax are louder than the woofers and the trebax is a little louder than the midax.

Three questions.

1. Do the capacitors in the crossovers need to be replaced?
2. Are there 16 ohm variable l-pads or is there a schematic of the original attenuators so I can duplicate them?
3. Would it be better to pass these on to someone who can use them with a proper Goodmans woofer?

SOLD

I have a spare set of fully populated and verified working Autoranger boards; the control board and the attenuation board. The firmware version is V1.5. These are the original boards / design.

Price / Payment / Shipping - $100 USD PayPal net to me. If I arrange shipping, buyer covers shipping at cost using UPS or USPS. Buyer can also PM me a pre-paid shipping label for USPS, FedEx, or UPS. I will provide shipping weight and dimensions along with other necessary details.

https://www.linearaudio.net/la-autoranger

The boards are tested and work properly. The system is not calibrated. You will need to do that if you choose. Per the manuals, it is functional 'out of the box', and I've found it to be so. The displayed voltage is slightly off (expected). I think most people would likely do the simple Accuracy calibration and CMRR checks and leave the FR alone.

Why did I not calibrate it? It's not necessary (to me). The voltages are close enough, and who knows... my hand-held DMM may be less accurate than the Autoranger. 🤷‍♂️

Will I calibrate it for you? I'll do the accuracy calibration and CMRR check for an additional $50. Why so much? B/C I don't want to take apart my other unit, and it takes time I don't really have.

Why am I selling these after so recently getting them and at less than the cost of the parts...? tl;dr - I wound up building two sets, and this community has been exceptionally kind, particularly Jan.

What else is needed to have a fully working Autoranger? A PSU, a chassis, and appropriate wiring.

PS - The display color is set to purple... b/c I like purple. Feel free to change it with the jumpers.

A foot switch for the computer keyboard. Press it with your foot and it presses the SHIFT key.

All the GD rules they make for secure passwords require TWO hands to enter them, and nowadays it is F ing constant. What do you do when one hand is full or otherwise occupied? You have to put it down to enter that stupid password again. The foot switch would allow it to be done one handed again, like in the days when it was all lower case. And still be “secure”.

I have realized that it is unlikely that I will be as active in this hobby as I once was, so will start listing parts for sale here in the coming weeks. First up is my collection of large heatsinks that I collected for Class A projects but never used. I'm sure I paid too much for some of these, so will probably end up selling at a loss despite increases in metal prices, but such is life.

PayPal is probably easiest for payment. Will ship within the US at buyer's expense; contact me with your ZIP code for a quote. Will consider shipping to other countries, but shipping may be prohibitively expensive. Local pickup in western Illinois is also a possibility, as is meeting part way of schedules line up to allow travel.


Lot #1: pair of silver heatsinks which do not appear to be anodized. The bases look polished, and the fins are maybe oxidized aluminum instead of anodized. Fins are "serrated" for increased surface area and better dissipation. Some holes drilled and tapped in base. Each sink measures about 10.25" wide, 9.875" high, 3.125" deep, with a 0.625" thick base, so the fins are about 2.5" tall. Each sink weighs about 13 pounds. Each sink has small cutouts at the bottom of a few fins as shown in pictures. These were very expensive when I bought them because of their size and weight. Asking $75 for the pair. SOLD

Lot #2: pair of black anodized heatsinks which appear to have been salvaged from an amplifier chassis. These have some channels cut in the top and bottom for mounting. Some holes drilled and tapped in base and some scuffs in the anodizing. Each sink measures about 10.25" wide, 8.125" high, 2.625" deep, with a 0.625" thick base, so the fins are about 2" tall. Each sink weighs about 11 pounds. Asking $65 for the pair. SOLD

Lot #3: pair of clear anodized heatsinks which have done holes drilled and tapped all the way through the base and fins. Good shape overall with the odd dent or scratch here and there. Each sink measures about 9.75" wide, 9.875" high, 2.25" deep, with a 0.25" thick base, so the fins are 2" tall. Each sink weighs about 5 pounds. Asking $35 for the pair. SOLD

Lot #4: three black anodized heatsinks which have a grid of holes drilled and tapped in the base. Some scuffs and fins on the sinks. Each sink measures about 7.875" wide, 5.875" high, 1.5" deep with a 0.375" thick base, so the fins are about 1.125" tall. Each sink weighs about 3.5 pounds. Asking $25 for all three.  SOLD

Please see pictures in subsequent posts for details about each lot. Note that measurements are rounded to the nearest 0.125" for simplicity and weights are approximate as my scale's accuracy is questionable.

Over on FB a guy is selling 6418 tubes for a buck a piece. I had the thought that 10 in a row might make a good OTL amp. Opinions??!

A friend of mine is planning on building enclosures for his Lii audio fast 10 drivers. He asked me about the enclosure design, and I could not give a good answer but suggested I'd try to ask here. These are probably very trivial questions for most of you.

Firstly, with the design below, would it be possible to place the vent hole at the backside...? I assume no, but would like confirmation.



Secondly, are there supposed to be sidewalls to that vent slot? My friend made some nice renderings to explain the alternatives. So should it be like this:

Or like this:


Thanks in advance!

Hi guys, it's funny how our interests come and go and then come back as years pass by, and I've been on many journeys since I last posted on this forum.
Any hoo, I hope I'm posting in the right place here.
I purchased a pair of pre loved Sony SS-S9 6 ohm 120 watt speakers cheep $20 for the purpose of setting up a class D blue tooth sound system for my Daughter and Son in law.
I use the same amp on my old floor standing Sansui 3 way speakers and they sound wonderful, however I was very disappointed in the performance of the Sony speakers.
There is no brightness to them at any volume. very little high's and mids. These speaker had some good reviews in the past so I expected a little better. I disassembled one of them to find no crossover at all. I'd like to see if I can bring some life into them in a minimalist sort of way. I have to admit that I'm struggling with the whole crossover design thing. I can understand how a crossover can be designed around speakers with known values, but I don't get how one can work around a 3 way speaker system with no data. In fact I don't even get how one can purchase a generic crossover to work on un known speakers. I've spent the last couple of weeks trying to answer these questions for myself with no satisfaction.

The Sansui speakers I use are 40 year old S-915 8ohm 120 watt. They kick ***.
Any input would be greatly appreciated,
regards to all,

Walt.

I know....I can have small .......or high sensitivity...

I have a few tube amps (PP and SET) ranging from 2W (Tubelab SE) to about 14W (PP triode EL34's) and I'm currently using Tang band W8-1772 full range drivers in bass reflex enclosure.

Before these I had some Fostex 207's in a half chang enclosure.

Both of the above are obviously floor-standers...

They sound quite good although I usually end up using a powered 12" sub for some bass augmentation.

..so if I'm running the sub-woofer anyway, I'd like to try some ribbons in a small enclosure; something without whizzer cones too....

I have a pair of Fountek Neo CD 3.0 ribbons that I would like to build with a small (4"-5") mid-bass or full range driver and need some suggestions...

So far I'm considering the Tang Band W5-2143 full range driver...perhaps MTM?

Tang Band W5-2143 5" Paper Cone Full Range Driver 8 Ohm

or the Audax 13LB25AL full range

https://www.madisoundspeakerstore.com/pdf/13LB25AL.pdf

My thoughts are run the 5" driver full range and a simple 1st order on the ribbon crossed over quite high.....

The Audax is intriguing since it's 96db sensitivity .....gives me a little headroom to burn up doing BSC, etc

Thoughts? Issues with this approach?

So, my last post was three years ago, and the Dynaudio TL project in my avatar is long gone. For the last couple of years I've been listening to a pair of Mirage M3Si's I rescued from a skip and rebuilt, and slowly putting together a front end to feed them. The Mirages are now gone as my good lady thought they were too big for the current house (which they absolutely were) and we're aiming to downsize.

My DIY skills are enthusiastic and knowledgeable but lack any real ability, so I’m keeping myself sensible as to what I take on. My mantra for the whole system has been “Grand Enough for Spotify”. Every time I think about spending money on “Audiophile” stuff, I go back to the Mantra… the “Grand” is the nominal budget for the whole system. Source material is Spotify Connect only. I stopped kidding myself I needed any other source when I realised I couldn't hear anything over 11kHz anyway. 🙄

Front end consists of a Raspberry Pi (3B+) with 7”screen and a HifiBerry Digi2 Pro HAT, running Volumio. The optical output from the HAT goes via an old Musical Fidelity V-DAC and a passive volume control to a power amp using Icepower 300AS1 and 300A1 modules. Total cost of all that is about £500, leaving something similar for speakers. Now, if I’m honest, I should buy myself a pair of half decent standmounts and live with them, maybe with the BK sub I still need to fix, but that doesn’t scratch my itch to spend money unwisely on something unsaleable that I “built myself”.

I've been hunting for something smaller than the Mirages while remaining interesting, and up pops a pair of Wilmslow Classic for sale. I decided they were what I wanted and organised a long weekend with the Mrs at the wrong end of the country to collect them. What are they? A Volt BM220.8 mid/woofer and a Scanspeak D2905/950000 in a very solid, 40l floor-standing tower. Similar to the current SM108 kit from Wilmslow, but in a taller and larger box. I was surprised when I heard them (quietly) in the seller's flat. They sounded like a mini-monitor and had no bass worth mentioning. Of course, I bought them anyway and brought them home - I like a challenge!

Got them home and turned them up, hoping a bit of volume might help, but they only got worse… Playing quietly, they were detailed, clean but somewhat uninteresting due to lack of bass. Turned up they just got harsh, sibilant and generally unpleasant. Without measurements, they seemed to have far too much output in the crossover and lower tweeter range.

I pulled them apart to investigate…

I want to use guitar with HiFi headphone amps and I need to make hi impedance input circuit. I already made it with a single JFET transistor and it works perfect, but I want another version with a bit more available gain, right about two stages, that seems like optimal gain reserve.

I already built it some time ago, with this circuit I found on Google images and I remember I had a lot of trouble getting it to work and to find optimal bias points and at the end I couldnt make it, I ended up with circuit that has less gain than single transistor version. So I would like to do it better this time, mandatory JFET at first stage and another JFET or BJT for second stage.

https://www.next.gr/uploads/8/JFETBJTBUFFERSCH.png

https://apocalypseaudio.blogspot.com/2010_05_01_archive.html

For available JFETs I have BF245C and 2N3820, and for BJTs 2N3904 and 2N3906. What circuits do you suggest, I appreciate schematics and links to articles. Working voltage 5-9V single rail.

For you folks that want to see how the other half lives, here’s a VERY impressive new driver from Dayton that would be super simple to design your first two way system!

https://www.parts-express.com/Dayto...ure-Series-Woofer-80W-Driver-4-Ohm?quantity=1

Notice the efficiency……even with baffle loss we’re still right around 90db…..easy to drive

And the 30 degrees of axis response?……are you kidding me……ruler flat to 3khz

I got a Marantz 2325 receiver that I'm thinking of selling.

It was fully rebuilt last year, I got the bag of parts to prove it.

I had a specialist work on it. He took all the boards out, cleaned them, replaced the components as needed, caps, diodes, etc, etc... his replacement of such, ie: caps was done understanding their usage, not your typical "shotgun replacement". The only place where he "upgraded" the caps was in the power supply.

I believe the power transistors are still original.

We found a lifted trace on the FM demux board, so he jumpered it.

Replaced the lamps with somewhat lower wattage to preserve the velum -it's in very good shape. All buttons, slider, knobs work. We couldn't test the Dolby system. Phono preamp works; tuner works, tape monitors work; inputs work; lights work; volume and balance work...

In essence, my instructions were to rebuild to factory OEM spec. My plan when I get a vintage unit rebuilt it to bring it up to spec, not make it better.

But, as it just happens, I got too many things and I need to make some room in the closet... and to me, a 1974 OEM Marantz 2325 just doesn't sound so good. It has a "thick" sound to it. Bass is indeed powerful, but it's just no an agile unit. Sure, it looks great... like a beautiful 747 cockpit, but my current crop of goto amps are just a plain box with blue front panel switch.

Money... it was given to me eons ago and I spent 1100 bucks to restore it. I will provide the bag of used parts as proof and the name/number of the guy who worked on it.

Fools and flippers on ebay are asking 3000 or more bucks. You know the type? New LEDs! New CAPs!

If you're interested, PM me and we can discuss it. I'm only greedy when it comes to ZM's stuff. I can take pictures. I would like to sell this to someone who appreciates it and realizes that it is a 50 year old vintage receiver.

Hi, my Nakamichi TA-4A Stasis has a balance issue, the right channel sound louder that the left channel, with the oscilloscope I checked and the issue is the in Tone board, the input signal enters equal on both channels but at the exit to the main board, the amp board, the right channel is louder than the left, I have read some posts in these forums and I saw that some users have been working on giving service on Nakamichis, so I hope someone could help me to find the issue, I measured all the components in that board and all the values seems normal, In a post on these forums read that the culprit could be a resistor that heats and give wrong numbers, so I hope someone can help me.

I forgot, the display just don't turn on too, and the led on the phono button when I press it it turns on briefly then turns off, so I need to fix that issues too, thanks for reading and help me.


thanks
Jerry

Can anyone help with a schem for this pizza oven?. The specimen I have has run so hot that many components are blackened and unreadable. The PCB FR4 has considerable brown patches and much rehabilitation with bits of tinned copper wire needed hence I need a roadmap. This one uses J50/K135 mosfets.
Cheers, M

I made a small electric fence situation on my patio to keep my cats from going to my neighbors patios. (Trust me when I tell you I’ve tried everything else before resorting to this.)

I got the Patriot PE2 and used chicken wire to ground. I just tested it out and it definitely works, but far too well for my small cats.

How can I reduce the amount of shock it puts out? I tested it on my self and holy shirtballs that thing could stop a cow. Which I realize is the point. But still.

I am trying to follow the (attached) instructions to add RFI filter capacitors to the power leads connecting the power supply and preamp modules of my Audio Research SP10. The problem is, I cannot figure out how to remove pins from the connector! The illustration provided shows little "fins" that could be depressed by a pin tool, but I don't see any evidence of these fins in the pictures.

Can someone tell me why my crown macro tech 2402 is shutdown on Ch 2.... With the back board disconnected I'm getting 100 volts + on one of the rail and 9 volts - on the other

I am thinking of building a 7-channel and a 4-channel class D power amp. I have not done these sort of DIY products but it certainly sounds like loads of fun as long as I have clear instructions. This is what I'd like to know:-

1. I am thinking of using Hypex modules as they seem to have a good reputation.
2. Any suppliers on AliXpress who supply nice simple metal cases? - A standard black metal case designed for 7 channels would be nice as it can be adapted to 4 channels too. Rack-mounting brackets would be great.
3. Is it possible to get good quality interfaces from AliXpress - XLR, speaker binding posts / Speakon, mains power?
4. Where can I get all the internal interconnects / cables? - from Hypex?
5. Are clear instructions available in terms of how to install the boards in the case and make all the connections?

Some people say that building a class D amp can cost as much as a new ready-made one of the same specification, any thoughts/opinions on this? - I'm sure members here who have built their own class D amps will have a good idea.

Any help, input, advice and tips will be appreciated.

Currently, I'm working on this DIY preamplifier: https://tataylino.com/guitar-preamp-design/

Here is the circuit for it:

I wanted to know a couple of things. 1. What is the input? I am planning on connecting pedals to the input of this but I want confirmation that that is the right thing to do. In addition, what is the output? Will this plug directly into a speaker or an amplifier? If it plugs into an amplifier, could someone link me to a DIY amplifier schematic that I could use for this? I am trying to do this "as DIY as possible", so no kits or anything, I want an amplifier schematic that I can build in Altium, etc. Thank you!

What are the pros/cons of starting out a pi filter chain with an RC stage as opposed to a C stage? Right after the rectifier stage. Would you do this simply to obtain some needed/desired voltage drop? Is the waveform pre-conditioned in any way like an LC or otherwise? Would you do it because it makes things easier on the diodes and first capacitor? What is the difference in how the whole filter is operating, if any? Drop, regulation, conduction angle, inrush, ripple, shape, etc...

Event Tr8 XL monitor loud electric click/high freq pop, when switched on, Occasional feedback. Any Advice would be great please. Thankyou

I have a audio interface that is nearly obselete with drivers on their last legs. I wondered if occasional driver digital overload, could have damaged the monitor?

As a novice. Was going to have a quick look, to see if anything obvious fuse or wire, wondered best/easiest way to also get in them. Front woofer removal or total wood front panel prise open? As back is sealed.

Thankyou very much.
Any help or advice would be appreciated 🙏

long story short I have a pair of m-audio m3 6's and one of them got smoked, tried taking it to a guy who repairs audio equipment and he said there's nothing he can do without the schematic.

i spoke with a guy on Facebook who said he just threw a 3-way crossover in his and it worked great.

I'm totally fine soldering stuff but when it comes to board work im noob.

can anyone recommend a really good ($75-$150) 3-way crossover that would be plug-in-play minus the cabinet work?

*link to speaker specs in speaker name

Hi everyone, i need your advice for integrating a subwoofer to my sealed fullrange speakers. This is more like an experiment rather than building a serious system so i'm not looking for 100% accuracy.

Here is my plan--- I have an discarded 2.1 ported box with 5 inch sub without any electronics. So i decided to build an active sub to assist my fullrange spkrs at low frequencies. I don't want to use any filter (i can do simple passive if adviced so) for the mains/satellites but want to boost frequencies below about 150hz. My question is how to do it? Attaching the link of the PCB & Schematic which i want to use as subwoofers low pass filter. I have everything in my possession, so i just need to buy the blank PCB.

https://mypcb.linker.store/products...r-home-audio-systems-assembled-board-10807078