Hello everyone, it's glad to be in this forum, looking forward to learn new things with ya 🙂

hello,

i tried now around 10-15 different dacs and specially recently some really nice sounding not much costing devices come around

somewhat recently i found out that i really like the sound of the black lion audio revolution 2x2 interface, then 2 weeks ago i was looking for the first time into portable dacs (not much of a on the go listener, im looking into this for desktop use), tried the moondrop dawn pro (good for the money, but overall compared to more expensive amps not a endgame solution), then bought the Fiio KA15 ... much better imo and actually pretty close to the black lion audio interface (maybe/probably a Cirrus Logic Dac chip thing, which i also wanted to confirm as the moondrop dawn pro relys on CS413131 and the fiio KA15 on CS43198 + OPAMP (i upgraded to KA15 since the base sound of the moondrop dawn pro wasnt sounding bad, it was just a bit thin/brittle sounding which you usually get with small amps)

not just sound quality seems top notch on the Fiio KA15 but also its featurset, the dac chip seems well implemented you even get a class AB or H mode option (which is a function of the dac chip made accesible by fiio), also all digital filters are selectable

So, since the chip seems well implemented, i was wondering, can this thing be used as a base to DIY something? the recent collection of portable dacs measure pretty similar to desktop units to be honest
i already hooked it up to my active speakers via a 3.5mm to 2x cinch and also can confirm here, it sounds pretty good (but good usb filtering seems still beneficial, had to use a isolator since there was audible noise over cinch)
would it be possible to use this as a frontend and build a "output stage" for it? the output opamps are SGM8262-2 inside KA15, not sure how these react to high impedance loads, does anyone know more here? i just assumed if it can drive low impedance it can definitely drive high impedance...

Seventy years ago I was gifted with a Lionel train set by Santa (or so I thought). I was so excited I peed my pants twice. My dad's factory had a railroad siding and I loved when the locomotive would slowly move by the office when years later I did some of the book-keeping for the company.

I promised my sons that the first one who sired a child would get the train set. It is now in wonderful order with #2 son and their kids!

Recovery bed ponderings

With folks making efforts with bracing and damping, I got thinking about the other extreme. I imagine a sub driver fitted into the entry of a balloon and inflated to atmospheric pressure or so

How would that go? Thoughts?

I want to use either the BD139/BD140 or the MJE243G/MJE253G pairs as driver transistors for a low power amp. I have around 100 BD130/BD140 pairs with an hfe of around 200 and getting numbers of perfectly matched (<1%) pairs is not a problem. On the other hand the MJE243G/MJE253 are a mixed bag with hfe ranging from 80 to 140. I get probably get around 15% of pairs matched to within 5%. I realist that by themselves the MJE243G and MJE253G are better transistors. Which would you use?

Hi everyone,

I’ve been restoring an old equalizer and recently replaced all the electrolytic capacitors. Everything has been working great, but I ran into a small issue with the last capacitor I replaced.

According to the service manual, this capacitor is supposed to be ceramic (non-polarized) with a value of 0.022 µF. However, the original one soldered on the PCB from the factory was an electrolytic capacitor, and its value was 10 µF. When I desoldered it, I didn’t note its orientation, and now I’m unsure about the correct polarity for the new electrolytic capacitor I’ve installed.

The capacitor is located between the ground of the LINE OUT/REC OUT connectors and the general chassis ground. I’ve installed the new capacitor with the negative leg facing the chassis ground, assuming it’s the lower potential point.

Does this orientation sound correct, or should it be reversed? Any insights would be greatly appreciated!

Thanks in advance!

Hello all this is Andrea and I'm the owner of aaelectronics, a project that I started 5 years ago with the idea of improving DIY amps construction 🙂
Nice to meet you all!

I have been out of the electronics game for a few years minus a couple foot switches and the like, looking to get back into it with this project.

I’m wanting to build a small personal monitor mixer to use when I’m gigging. One (1) XLR input that would be my mix from the monitor console. One (1) stereo 1/8” input jack to bring in all of my sounds coming from my computer which controls all of my keyboard sounds. One (1) 1/8” stereo output jack to plug in my SHURE 215 IEM buds and hear everything. I want to have a gain / level pot for each of the two inputs to control the mix between the two and a master volume pot.

I would love input and thoughts from others on best way to achieve this and things to make sure I’m paying attention to.

Thanks in advance.

So I want to know why/what can cause the stereo image to shift off-center when everything is spot on in terms of speaker placement/amp equalization. I've switched both amps and speakers and the image is slightly left no matter what. Soundwise it's not an issue but it just looks wonky from my listening position and it's distracting. It keeps me concerned about something related to placement or the amps. I use Acoustat Model 3 with the servo charge tube monos. TIA

Adapters include Amanero i2s output via U.FL, DIYinHK i2s output via U.FL, and DAM1021 Inputs. Inputs are i2s via U.FL, and SPDIF via header as well as 3v3 input for isolator. I'm just looking to get shipping cost only, which should be like $5. I can ship internationally, but would need $10-15. There are two full sets and one set that includes only Amanero and DIYinHK adapters.

Hi everyone,

from past grand HiFi-building plans out of love of Mr. Pass and Audio, I have quite a few unused pieces to offer.

I am starting with two sets of fully specced 5U Chassis by Modushop Hi-Fi 2000 of Italy, I believe those are the same as the Deluxe 5U Chassis.

In particular, each set consists of:

Dissipante 05/500B 5U 10mm SILVER 1NPD05500B
Inner baseplate for Dissipante 500mm 1BASEPD500
Couples of round handles 5U 1MT05158N
Couple of silver milled 5U handles 1MAN05B

Current price of one set is about 366 without VAT or 435 with European 19% VAT. (DIYAUDIO Chassis is 460 USD without tax and handles)

I am located in Germany, Berlin.

I will sell each for 300 Euros plus shipping - they are very heavy (20+kg per piece) but inside Europe I think Hermes will offer decent pricing.
They are still in the original bubble wrap, so I will forgo posting pictures, but if you need some, drop me a message 🙂.

Once I have worked out what else I have, I will post it here. There should be a few interesting amp boards (F4 F5) and their respective transistors / JFETs.

Hey all, I'm fairly new to building amplifiers myself but I have built some smaller electronics in school as well as repaired some things on my own time.
I've been contemplating building a headphone amp for a couple years now and finally decided a couple months ago I'd try to build RJM's Sapphire headphone amp.
I'm now mostly finished building it and wanted to share my results in the thread for it.

Cheers

Joe. New to the forum. Wanting to get back into DIY audio projects and it’s nice to have a community to bounce ideas with.

There are many, many Kef B200s in the UK and elsewhere. Mostly SP1014. Both used driver units and 2-way speakers from Kef, Tangent, Monitor Audio etc. All going pretty cheap. Crossovers on these models were always between 3K and 3.5K, which was the style at the time. But several posts have suggested crossing the B200 over lower, like 1.5K to 2K with a more modern tweeter, maybe in a waveguide. Here's the data below, so what do you think?

Hello all,

I have a quad (x4) of NOS Neutrik NC5MX 5-pin Male XLR Connectors for sale, still in their original packaging!

Full part number is NC5MX

I'm thinking USD 20 for lot plus postage or open to offers

Cheers, Ralph

Two more DACs for sale, fully built and working with high quality components, Need to raise some funds for more adventures 🙂

Both DAC boards have op-amp output and need +/- 5V supply. It is advised to test at 5V and then lift links to supply op-amps with 12 - 15V.

DACs need I2S input such as XMOS USB.

PCM1702 -SOLD

AD1865 - £40 plus shipping

Paypal either friends or add for fees.




Update Wednesday 30/10: One AD1865R DAC fully built available until I get more components, have DAC chips for 3 more after that

The Dayton DA135-8 list the xmax to 3mm. https://doc.soundimports.nl/pdf/brands/Dayton Audio/DA135-8/pdf_Dayton Audio_DA135-8_1.pdf
Isnt that very small?
Anyone tried this driver?

Hi everyone, just wanted to know if someone can help me with finding the problem off small crackling noise coming from my Sit3 left channel ? Is it possible to be capacitor failure on left channel power supply after living the amp switch on for days?

Hi guys,

I'm designing a low noise linear regulated power supply for my phono preamp which is now using a cheap wall wart power supply.
I need 18v with 1A max and I'm going to use a Belleson SPX regulator.

What I like to know is how much filter capacitance do I really need. I'm thinking of using 4 2200uF capacitors as a filter capacitor bank. I think it will be more then enough, but does it make sense to use a larger capacitor bank? Or what is the advantage of using a capacitance multiplier (capmx) with smaller caps?

Transformer will be 18V/1.6A and the regulator is an 18V version.

Hello,

I'm started to design master clock and need to know your opinion about this idea,

This OCXO idea is master clock for https://www.ti.com/lit/ds/symlink/lmk05318b.pdf ! The final master clock out will be trought it and will be fine corrected trought gps, thats for later. This oven also have oven controled voltage reference 2.5V which I going to use for J.D. regulator which will supply this OCXO. I done pcb oven design, picture 3, pcb will be canaled from all sides and an metal case will be soldered on booth top and botton layer, over those metal case going another metal case isolated by silicone. I thinked to do Driscoll crystal driver but it is complicated, instead I think I will do it with Comtrue CT7302PL since that ic have 190db dynamic range and an thd+n -175db, it will drive SC Cut 3rd ot crystal perfectly well and will give me master clock on their mclk out in TTL format. Oven is driven by darlington MJD122 and 40 resistors 1k which give around 25 ohm load, those 40 resistors will evenly heat the central part of the pcb on which is placed sc cut crystal and AD780 bangap reference which have temperature out which I have used for oven fine control. Waiting your opinion regarding circuit schematic design! Thank you!

Does anyone have good clean copies of these articles?
There are plenty of rough copies but I find generally that anything in this mag is hard to find, unlike WW which every issue seems readily available.
Maybe I've missed something.

So a friend has asked me to design a strain gauge phono pre-amp based on the Panasonic strain gauge cartridges.

I've got an EPC-460C and an EPC-465C on hand along with two NOS replacement styli.

(Even better I get to keep one of the cartridges when the project is done.)

I have spent several days reading VE and AK threads about these cartridges and how to amplify them.

Many people seem to like them without any sort of EQ, but based on measurements posted on VE and elsewhere this doesn't seem correct to me. Reviews back in the day show FR plots that by today's standards look pretty bad.

I might mention I have heard several modern strain gauge cartridges and thought they sounded absolutely terrible. I also heard a Panasonic with some limited EQ that didn't.

To be fair my frame of reference are a couple of Ortofon Per Windfelds. I have several others including a couple of SPUs, but I feel the PW is the most accurate cartridge I own.

From extensive study it seems like the following might be true..

• HPF at 50Hz

• Shelving HPF filter between 500Hz - 2.21kHz

• As yet undetermined rolloff between 2.21kHz and 10kHz..

All subject to change as I figure this out.

Hello,

I built the F5m amp with Nelson Pass PSU. I would like to add a small microcontroller inside the chassis to allow me to control the front panel LED(s). My board would draw under 200mA and the voltage regulator input has a max of 36V.

The Nelson Pass has +-24V rails fed from the transformer sourced diode rectifier bridges(2). Can I tap into the GND and +24V rail on the PSU board to supply my microcontroller voltage regulator or will that potentially cause a negative side effects on the F5m circuit/audio? My board would power a couple of LEDs at 20mA each or so and it will be using PWM so I don't want that interfering with the audio.

Thank you

What material do you recommend for making a linear power supply?

Hello everyone, I have some DACs and headphone amplifiers, as well as some preamplifiers and amplifiers. I now wants to create a linear power supply to power my DACs and headphone amplifiers, without the need for power amplifiers. My idea is to make two DC12V/3A and two USB 5V, with a total output power of about 80W. I want to use some better materials. Do you have any recommendations?

Welcome everyone to provide suggestions.

I have one output transformer Lundahl LL1693 250mA. I used it for experiments with 6S33S based amp. I think that amp sounded the best I heard. However, I decided to take another route due to the size and the fact that 6S33S needs at least 30 min of warm up time to sound its best. Happy to share my experience and knowledge if interested.

I still have the original shipping box. $200 + shipping. Feel free to ask questions.

hello everyone, I have been doing audio repairs for many years but you never stop learning new things.
I have found a lot of knowledgeable people here from whom I can learn new things and I hope to be useful for something too.

New to this forum, I recently rebuilt my speakerlab delta I type 4s with help from Paul from the loudspeaker store. I bought these as a kit back in the mid 80's. I have a Denon PMA-700V from same era and thought I would give it a little attention. It sounds great with the above speakers at low volume but I realized the speakers needed new surrounds, and the 8 in drivers were shot, hence the rebuild. With Pauls help, I added a true Nestorovic circuit to the coupled 8 in / 10 in bass driver circuit. So with these speakers revitalized, I thought I should take a look at the PMA-700V. Two of the 8200uf 63V power supply caps appear to have stained the glue on the PCB. Since the amp was working fine I am hesitant to just blindly recap it.

This project started 4 years ago, but lots of things happened in between and i was only able to complete the speakers today 🙂

Design

Here the speaker dimensions, as designed 4 years ago:



Drivers

• Beyma 15MC700nd: X < 350Hz
• AE TD12M: 350 < X < 1500Hz
• Beyma TPL-150H: 1500Hz < X < 20000Hz

(Crossover points will be dictated by real measures, but should be around those values).
Crossover will be Active, using a Monacor DSM-48LAN.


Boxes

Here the empty boxes, before stuffing and final coating:








Final Speakers
(sorry for the low image quality, i'm a really bad photographer)

Grills off:



Grills On:


One full speaker weight around 60kgs!

Some details

The backplate for the TPL-150H was removed, leaving the felt protection:



Drivers were stuffed with a mixture of:

• 4mm Bitumen pads glued to the walls
• Wool felt glued to the bitumen pads
• One high density rockwool 70 kg/m³ wall at the middle of the box
• Low density "fluffy" rockwool 30 kg/m³
• Raw wool

Initial Driver Measurements
(just for checking everything was ok)

A nearfield measure for both TPL-150H boxes (measured indoor, with ceiling at 1.8m at the measurement position):




A nearfield measure for both Beyma 15MC700nd boxes (measured indoor, with ceiling at 1.8m at the measurement position):


(i accidently removed the measures for the AE TD12M, but both tracked perfectly as well).
You can find detailed measurements for the AE TD12M on drivervault.

Finally, a nearfield measure for all drivers (measured indoor, with ceiling at 1.8m at the measurement position):


Next step

I'm now waiting to receive a 1200mm x 610mm x 3mm MDF board, so i can draw the exact positioning for the 0º to 180º measurement using the Ground plane technique, to get the required measures to use with VituixCAD for crossover development.

I'll be requiring your help for fine tuning the crossover once i have all the required measures, in order to obtain the best result possible 🙂

House cleaning. Two meridian system remotes for sale

€130/each + shipping at cost.

R

$300 shipped USA.

One pair never used 60 watt high quality Heyboer output transformers. Would make great 6L6GC pentode amp.

All new, $100 shipped USA.

The 2 chassis are old but never used. No top plates, just the chassis. They each measure 17x13x2.

The Hammond cage measures 17x10x5. It does not cover the whole chassis but does fit nice and snug over it.

Sold.

Hello,

I'd like to discuss with you some details in the phono section of the venerable Audio Research SP-10 preamplifier. It's phono stage comprises four 6DT8 double triode tubes per channel, which heavily resemble the 12AT7. Both triodes of each tube are paralleled, most probably to decrease noise by 3 dB. There are SS arrangements in each stage's supply which I believe are inductance simulators/gyrators. RIAA equalisation is done per NFB, which not everyone would follow. So far so good.

What I really don't get is the stage arrangement. I would have swapped stages 1 and 2, as I think, the cascode works best as the 1st stage. Additionally, Miller capacitance of the 1st stage is dramatically increased by 100 pF capacitors between the grids and the plates and adds to another 100 pF between grids and cathodes. A very heavy capacitive load for the cartridge, I think.

Does anyone have a clue what might have Audio Research led to design the RIAA phono preamplifier this way? Thank you!

Best regards!

Unfortunately I haven't a picture from this neon lamp, because it was already remooved.
This neon lamp is inside in the tubus (left side of the attached photo) of follow record player:
MICRO ƒŒƒR�[ƒhƒvƒŒƒCƒ„�[SOLID-5‚ÌŽd—l ƒ}ƒCƒNƒ��¸‹@

The manufacturer of this neon strobe lamp was Elevam:
Welcome to Miyata Elevam Inc.

Unfortunately it was not an article from the standard range. It was a custom made version for Micro.

Perhaps in Japan such lamps are still available.

Not helpful are normally used neon lamps in turntables like the photo number 3 and 2.
The greatest similarity I note to the both last pictures from attachment - found by a great overview of such lamps
Glimmlampen für Signal- und Beleuchtungszwecke

I am a musician , I use Hughes and kettner 20W deluxe tube amplification in my band and studio , my home Hi-Fi is a Arcam A39 speaker's mission 796 , I have recently added a Nobsound A3 tube amp to my home Hi-Fi stereo system , blessings

I've always wanted to build my own speakers and amplifier from scratch. And I did — they even sound decent. But there's always room for improvement, and I hope to find help here, and maybe even be able to help someone else.

Hi Mooly,
I have no way checking the connection condition?

During searching a connecting cable from my old stock I found a JVC radio set, consisting radio, cd player and cassette player. Please refer to attached photos
To my surprise the cd player still works with good quality of sound. The JVC radio set is >25 years old.

I'm now searching how to connect the cd player to my Denon HiFi amplifier for testing

Hello Everyone. Myself Sacheen Mahurkar from India. I am into vinyls & turntables.
I have been trying and attempted my hands on Moving Coil cartridge. Did lot of experimentation & research and then finally used Rosewood for the body, O.O3mm 6N high purity copper wire for the coils and currently using elliptical stylus and Neodenum magnet. Believe , its sounding fine. Would like to take this further. Please share some thought & views.

Have a pair of used Magnepan 1.7 speakers with an open supertweeter foil. Since this is aluminum foil, using silver or copper will cause corrosion just like in house wiring when copper or silver are touching aluminum wiring.

I found some nickel based conductive adhesive for a situation like this. It comes in a small applicator to paint on.

The glue on the panel with the open trace is the one that is brown in color on the right. The glue has been exposed to UV, so some of that will be removed once I find the foil break. It seems to be at one of the foil folds near the bottom of the panel.

I do have a full foil repair kit from Magnepan to use, but want to try a reoair first.

This pair has been converted to direct drive for use with a DSP crossover and Class D amps. Will be putting a 2 Ohm resistor in series with the supertweeter foil so the impedance is high enough for the Class D amp to have full frequency bandwidth to drive it to 20KHz. Below 2 Ohms, the typical Class D amp high end starts rolling off the frequency response.

Anyone that has tried a quasi ribbon repair would be great to get any tips. I have the acetone and alcohol recommended to clean the glue from the foil and cotton swabs to remove the paint and glue before repair.

I've been testing a Sabaj A20h and it sounds perfect as far as I can tell. The good price, perfect specs, and quality relay attenuator seem top class.

My idea is to combine a number of these units to make a multichannel attenuator - to be controlled by a 'master unit'. Does anyone have a schematic or experience of this hacking this? On first inspection the amp and attenuator sections are connected together by headers - I imagine that some of these are relay control lines.

I wonder if anyone has had a similar idea before and can help?

Hi, I choose this medical grade SMPS to try out Mark Johnsons AmyAlice filter. Results were OK but not comparable with my linear PSUs. The added necessary filter makes the SMPS quite usable (when deciding for SMPS) but it makes costs of course higher. Still a nice experiment just to keep in touch with recent cheap electronics.

However it keeps blowing mains fuses. It can not be taken into service as it is unreliable. I even upped the mains fuse to an unrealistic 500 mA and it just blows without any apparent reason. So today I got fed up and disassembled the PSU. While disassembling I heard a rattling noise. This appeared to be IN the plastic casing of the resin potted SMPS. So it is not fully potted either. When I measure it at the primary side and shake the module gently I can see a short circuit happening on my DMM.

Since this is a medical grade PSU I think this is worrying. Now I am not fond of low power SMPS anyway and possibly I maybe attract problems just like people afraid of dogs always seem to get attention of dogs but my question is if anyone has similar experiences with these modules.

I would like to build a full range single driver speaker using Markaudo drivers but I’m having a hard time making sense of the product lineup. It’s unclear which ones are newer, older, and the pros and cons of the different materials. I’m hoping that if I describe my goals people can offer advice:

• My goals are low distortion, neutral to warm turning, great imaging and sound stage, simple design, and cohesive sound of a single point source. Cost is not a concern.
• I have DSP and can EQ.
• They will be used with a sub, crossed over between 60-80 Hz, I don’t need super low extension, but I guess it would be nice to have the option in the future.
• Cabinet volume can be up to 3 cubic feet / 85 L
• Single listening position, centered, 9 ft from speakers, I can toe in or not if needed.
• I listen mostly to jazz and classic rock, some metal and pop.
• Amplifier has 50WPC class AB
• I cannot hear above 17kHz
• I appreciate a great natural mid range - big fan of HD650 headphones.

Here are the drivers I’m considering:

• MAOP 11, 10, 7
• Alpair 12P, 12PW, 11MS, 10P, 10M
• CHR 120

I see that some models have treble peaks, but I think they can be reduced by listening off axis? Since my system is pretty flexible with DSP and subs, I want the drivers that offer the best technical performance. The paper cones look like they have the flattest FR but I saw some people say they prefer the metal cones? What's the difference between P and PW? Are the MAOP suppose to be their top of the line and are they worth it? Is CHR supposed to have more bass? Whats the difference between M and MS? Other than enclosure size, is there a benefit to the mid rage or treble of choosing a smaller diameter woofer?

Thank you!

The situation:
I am having some questions with VituixCAD. It is a magnificent software but the the more complex the software and the more complex and new (for user) task is - the more questions arise. The author is very cool dude and he made not only the software free for diy, but also pretty solid documentation, even with videos, examples, use with other software and so on.

I try to search the forum about (VituixCAD) some minor thing, or lets say some tool inside the software - Merger tool, I search "VituixCAD merger" and I am pretty much in luck, there is a somewhat related discussion - https://www.diyaudio.com/community/threads/vituixcad.307910/page-226#post-7786166 it does not answers the exact question, but at least it matches keyword. I am more out of luck when searching about other questions: Diffraction, IR-FR, Preference rating etc etc. Overall there are 230 and counting pages of discussion about it with all the separate sub-tools, all the scientific and pseudo-scientific "discoveries", saying thank you for the author, very very high level discussion, and simple "VituixCAD does not start on my machine". Everything is just a big mess. It turns into a daunting exercise for the software maintainer to answer all the repeating questions, all the honest but boring thank-you's and so on. There are additional problems for non-english native speakers where our minds are not understood correctly, meaning lost in translation or just poor grammar makes search 200+ pages thread a huge headache.

Why not make a sub-forum for it? Then we can make some sticky FAQ posts for 5-10 most popular questions, instructions and so on. There will be more room to breathe for the author, he could chime in only on complex questions, more basic stuff could be solved between simple mortals...

The same could be said about REW, Hornresp. Maybe also about WinISD, Xsim and some others. My apologies, if I forgot to mention some.

The rule-of-thumb and "2nd order crossover online calculator" era in speaker design is long gone, those software tools are like mandatory extensions of hands and brain pretty much in every task.

I think my suggestion makes the community more good than harm.

EDIT: Btw, I am not pushing the authors of the software to make it "official" support channel, it is just for us all to make classification little bit easier. Imagine this forum as a library - there has to be some order in it. Big pile of books about everything will not add much to the overall knowledge or its users...

Hi,I'm having a weird idle condition DC offset from LM211 itself, even with a 10k resistor wired across pin 1 and pin 2 of TL072. The LM211 input offset is almost zero but the output was almost -5V instead.

This test was carry out:
-no audio signal was applied
-all required supply voltages were presented on-board
-the output stages is discrete push pull based
-all resistor measured within tolerance, including the 560ohms pull-up to +5V at the LM211 output.
-all output fets were removed.

I have 2 pairs Exicon ECW20N20 and ECW20P20 16A Mosfets. I would like to make an amplifier with them. Could you offer me good desing ?
Thanks

I have ported box tuned to 35hz my understanding is half octive below trying to set at 27hz but get a humming anything below 80hz that's like 50 some hz away.

1x pair of Music Angel SE845 OPTs: These were salvaged from a working Music Angel 845 SE amplifier. Not much info on these, but amp specs say good for 15-20W. Were run at OP of 920V 100ma, so should be gapped for at least that. 4 and 8 ohm taps: SOLD

1x pair of Music Angel SE845 PTs : These were salvaged from a working Music Angel 845 SE amplifier. Amp schematic added, so the avid diyer can figure out the connections... SOLD

Will ship worldwide

Lets begin this , most people thinks TDA7293 is inferior chip to LM3886 due to dreadful reference circuit in datasheet.
Situation in TDA land is actually different, Jazz/Rock lover liked the chip for better HF response and sweeter midrange but Pop/EDM/Bass music people hated this chip for inferior bass response in comparison to LM3886.
LM3886 got inferior HF due to most horrible layout and lack of zobel in most mass market board.
In fact both chips are very close each other in performance, it all boils down to preference aka mosfet vs Bipolar (pick your poison).
This led to great war between LM3886 & TDA7293/94 users in forum.

I tested this circuit ±30v(maximum of my lab supply), at 29db gain, chip seems to be stable , I want to see if at ±35v if it oscillate.

This modification uses T Shaped feedback:
Theoretical advantages of T Shaped Feedback is well documented but i noticed a better sound quality.
Special Thanks to @danielwritesbac for extensive work on NFB and gain optimization,
Here, https://www.diyaudio.com/forums/chip-amps/226437-optimizing-tda7294-output-3.html#post3300269
Please Consult Datasheet first, My Drawing can be confusing,
https://www.st.com/resource/en/datasheet/tda7293.pdf
In Feedback , Either choose R1=R2 = 33k and R3 = 1.5K or R1=R2 = 22k and R3 = 1.2K.

Full Image: IMG-20200915-233005 — ImgBB
Doted Portion in Circuit is not tested.
Disclaimer: No TDA7293 is harmed in this experiment(as of today).

Quality RBH MC-616C Speakers (2-way L/C/R)
6.5" woofers, 1" tweeter 180 watts, 6 ohms, 89dB sens
191/2"W x 7 3/4"H x 9"D
Weight: 24 lbs.
MSRP: $479 each. I have three of these.
Also one RBH MCS-88 dual subwoofer.
£450 for all four items. You can pay using paypal to protect your purchase. Can ship for extra. UK only. Sorry no can demo. Pick up from west yorkshire available

Hello,

In order to repair an old monitor, I am looking for an equivalent of the very old SEAS 25F-EWX 10''/26cm woofer. The replacement part should have very close specifications, including the frame's diameter (261mm), to avoid new woodworking as much as possible. Otherwise if you know where to find this part second-hand in good condition, I'd be interested too.

Thank you.

I've been a bit obsessed with Germanium transistor amplifiers lately. They seemed to be very odd and mysterious things- exotic sounding elements in cryptically numbered long discontinued unobtainium packages, lurking about in funky nerdy cabinets, consoles and 8-track players, long ago disparaged, disgraced, and discarded by the wayside and almost forgotten. Wait- all that weirdness, plus interstage audio transformers and thermistors? Really? I've =GOT= to know more.

I lucked? into two vintage automotive 8-track players for $5 at a trash heap of a garage sale this summer. One was a Kraco in a classy brown wood grain vinyl wrap with chrome face, the other was a Muntz A30 4-track player, minimalist bare bones but in chrome as well. Old madman Muntz was fun to research, what a character he was, and since that one is a little more historic I'll tuck it away on the shelf of tomorrow and play with the Kraco. I despise 8-track, have ever since I was a kid in the 70's. You kick the damn cartridges around on the floorboard until packed with dirt, then jam one in the slot mid song and let it grind and gurgle along struggling to carry a straight tune. Them were the good 'ol days boy. Better than noisy AM radio or your cousin on the harmonica I suppose. Instant fodder for the trash can as soon as you could afford a cassette, like that was any better in a hot dirty car. I could not wait to rip the germanium amp out of that fine brown wood grain vinyl wrap, scrape out the 8-track guts like cleaning a fish, and see how it works. Maybe if it worked well I'll Frankenstein it into a different can to be a kick-about guinea pig test amp. Since it was basically free I did not have anything to lose and a lot to learn.




The amplifier was actually a surprisingly good but simple design from Japan. The layout of the amp was excellent and well thought out. The small isolated island of components in the foreground of the left photo is the transistor tape head pre-amp. This whole portion of the PCB was removed as it was no longer necessary. The tape head pre-amp output signal ran up front to the volume, balance and tone pots, then back to the power amplifier across the very back. The left and right silicon NPN transistor pre-driver circuits are at the farthest left and right ends, with the interstage transformers, output biasing networks, and speaker output capacitors as you move towards the center. The symmetrical and well separated layout with a good star-ground strategy was smart, helping to minimize oscillation since the overall gain has to be so high from tape head to speaker. The four totem-pole Sanyo 2SB474 PNP germanium transistors were mounted on the back plate with surprisingly long wire lengths used to connect them to the pre-driver PCB. Only two of the transistors needed a mica insulator, as for each channel one collector (case) was grounded to the chassis and the other collector tied to the output and floated at half the supply voltage (hopefully not shorted to ground by a tool during installation).



Since I could not find a free schematic for the Kraco KS-408A I hand traced out the circuit, and created the above schematic for one channel of the amp. The capacitor values shown are not the original anemic values- While recapping I have upgraded them to what would be considered appropriate given the smaller physical sizes available today. The original power filter capacitor was 1000uF, now 2200uF, the speaker output caps were 470uF, now 1000uF, emitter decoupling caps 47uF, now 100uF, and the two audio coupling caps were 1uF, now 10uF. All caps have higher voltage rating and are all still smaller than the originals. I moved the output transistors onto a small sheet metal test plate I snipped out of scrap and drilled the appropriate holes through so it was much easier to flip the assembly back and forth while making modifications and measurements.



In the original design there were strangely no emitter degeneration resistors (the 0.22 Ohm on the output emitters) as I had seen in most other comparable designs, even for 12V automobile. First, I had to learn what an emitter degeneration resistor is and does, (Thank YouTube! ). It serves as a small amount of negative feedback to the transistor, with many added benefits- It increases the linearity of the device, helps to stabilize gain, increases the input impedance of the device, and even helps to stabilize bias current across temperature. I decided I wanted to add some. I was not certain if this would force a change to the output transistor bias settings, and was pleased to find that they did not. Without the 0.22 Ohm resistors, bias current ran around 80mA at room temperature, and with them the bias dropped to about 60mA. There was no audible crossover distortion incurred that I could hear, so I just left the bias network alone. It is interesting that both the Kraco and Muntz design did not have emitter degeneration resistors, but did have thermistors to appropriately adjust bias voltage down with temperature to prevent thermal runaway. From the base to the emitter of each driver in the bias voltage divider string was a 20 Ohm fixed resistor parallel a 22 Ohm (at room temp) thermistor. The thermistor decreases it's resistance as temperature rises, decreasing base-emitter bias voltage when hot. I suppose the tiny thermistors were considerably cheaper and easier to accommodate than four larger ceramic emitter resistors mounted to the chassis. It is interesting to note that when I see thermistors used in this way in germanium amplifiers, it is typically a fixed and thermistor resistor of comparable values in parallel- This must provide the optimal temperature gradient, or maybe provide safety if the thermistor were to fail open? Interesting.

In my initial testing, using a full line level signal from my media player into the Kraco volume pot it was incredibly difficult to get a reasonable listening level with the volume pot just off the stop. The gain was way too high. In checking the schematic I found the first stage Q1, a basic H-biased common emitter stage had it's 1K emitter resistor fully bypassed with a 100uF, so it's gain was spun to the moon (2.7K / "little re") so it's cranking. I might understand this if it were contributing high open loop gain for inside the feedback loop, but it's outside the loop, so holy cow. The signal level coming out of the tape head pre-amp must have been very tiny indeed. Imagine how much noise must have been picked up shipping this tiny signal up front, through three different pots then back and into this very high gain stage. As a first pass, I simply removed the 100uF capacitor from across the 1K, dropping the gain to 2.7K/1K or 2.7X. That did the trick nicely. Now with full line level volume coming out of my media player the amplifier is at a strong but comfortable output level with the volume pot about half-way up. Feels about right, I might increase the gain a little bit later in fine tuning.



The next issue I found in my initial listening was that the high end was really rolled off. None of the crisp detail I should hear in my Sony SSCS5 test speakers, which are noteworthy for high end detail. I did finally find some specs at least on the Kraco, and it listed bandwidth from 100 to 8Khz. I assumed this was so sucky because of the 8-track head bandwidth, not the amplifier. I have certainly improved on the low end by increasing the coupling and output capacitors, but 8Khz seems like a joke. Referring to the schematic, I see they have a resistor/capacitor shunted across the primary winding of the interstage transformer of .015uF (15nF) in series with 3.9K. This would act to decrease the impedance of the winding and reducing the gain into the transformer at high frequencies. The f3db of the shown values is about 2.7Khz so that would be quite a roll-off. In reviewing several other designs I see that they either did not have this limiter, or if they did the f3db was more like 15-20Khz, limiting ultrasonic frequencies but not really audible ones. Certainly this was to prevent amplifier oscillation, and given the high gain of the input stage, shipping the tiny input signal all around the chassis, and the really long wires between the predriver and output transistors this heavy handed measure was probably necessary. I decided to test a higher f3db by changing the 15nF to a 2.2nF, for an f3db of 18.5Khz. I did not want to change how much correction this RC circuit applied, so I did not change the 3.9K, but adjusted the capacitor to change only at what frequency that 3.9K came into play. No oscillation was detected under any condition with my little pocket oscilloscope, and the high frequencies were MUCH better. Still not quite where they need to be, but much better.



Speaking of high frequencies, another area that would really need attention if I wanted to clear the cobwebs and make this into a higher fidelity amplifier would be the two 0.015uF (15nF, 15,000pf) capacitors from the base to collectors of each output driver. This capacitor is typically referred to as the compensating, or dominant, or Miller capacitor. It is used to prevent amplifier oscillation by setting the dominant upper frequency limit (and slew rate) of the amplifier to within a stable range. These values as shown are REALLY high. In some designs these are as small as 10 to 100pf instead of 15000, and generally only on one driver, not both. (I can't help but wonder if the Japanese manufacturer had a surplus of 15nF caps and just decided to use them everywhere they could.) Oscillation in an amplifier is just like feedback into a microphone on a PA system. Get the mic just a little too close to the speaker (increase coupling) and the high frequencies race in a loop causing a screech. In an amplifier however, this can be ultrasonic, you won't hear it or even know it's happening until the amplifier or speakers start overheating and smoking, and you need an oscilloscope on the output to even detect it.

Adjusting the value of these capacitors generally takes some iteration- You replace them with smaller and smaller values until you reach oscillation, then back off a bit. You don't know at what value oscillation can occur because it is highly dependent upon the gain, exact nature and amount of wire to wire coupling you have inside the amplifier, temperature, and use condition. You have to be really careful with this, and not tread too close to the edge, because if it's stable and you button it up, and it goes into oscillation under some other temperature or use condition it will cause damage. I think the fidelity of the amplifier as it is right now is sufficiently good I'm not going to mess with these right now. Considering the relatively long wires connecting the output drivers, I think the designer was overly cautious for a reason.



I didn't want to spend the money to buy a fancy aluminum box for this amplifier, so when I found a couple of tin plated steel bread pans (the small ones, like for zucchini bread) I could not resist. "Bake King - The King of Bakeware" was stamped into the bottom. The Bake King was born! I cut away the unused areas of the PCB (previously for the tape head pre-amp and the huge supply filter capacitor) and the PCB fit beautifully into the bottom of the pan. I used the hole pattern from the original back plate to mark and drill the transistor holes, and mounted the transistors sandwiching my sheet metal test plate underneath to give a little more thermal bulk. I used a Dremel tool to cut out the square hole for the speaker connector, which was an old AM/FM antenna connector block. The pot and chrome volume knob are from the Kraco, the input RCA terminals from an old console, and a chunk of scrap plywood. I tacked the PCB ground trace that ran around the outside edge to the inside of the pan with a soldering gun to hold it in place.




I power the amplifier with a switching 18V @ 1.5A wall wart, with an output plug that matches the power adapter jack from my scrap box. I have to say- it sounds pretty good, certainly better than it did as an 8-track player. The Kraco specs indicate it will drive 4W into 4 Ohms, and I have confirmed that with my 4 Ohm resistive load and pocket oscilloscope. Obviously it drives less into 8 Ohms, and sounds best under 2W. It's small, super easy to set up, and great for testing speakers, source components, or rigging up a test lead with alligator clips to test capacitors in series between the output and the speakers. It was a great exercise for learning about the care and feeding of germanium transistors, and I'm into it all of about $4 for the 8-track player and Bake King bread pan. Everything else came from scrap. Hope you enjoyed the journey with me, and remember, always "bake until golden brown".

-Warren

This thread is to share pictures, questions, tips & tricks for the Classic Aleph Amplifier for UMS Chassis.

Original Thread is here:
https://www.diyaudio.com/community/threads/classic-aleph-amplifier-for-modern-ums-chassis.379571/
Group Buy Thread is here:
https://www.diyaudio.com/community/...fier-for-modern-ums-chassis-group-buy.379734/
Build docs were in Post #72 of the main thread. The build notes are updated here.
Latest version:
Aleph 30 Build Notes - NOW REV V1.0g (17 March 2025)
Aleph 60 Build Notes - NOW REV V1.0f (17 March 2025)
Aleph 2 Build Notes - REV V1.0c (17 March 2025)
Aleph AC Current Gain Guide - Rev V1.0A (17 May 2022)
NEW!!! Aleph "Mini" Build Notes - Rev 1.0B (12 Apr 2023) - Thanks Mikerodrig27 for the input!!!

Board Dimensions PDF attached 27 Jan 2022

AC Gain Procedure described in Post #237

Please see the build doc for details on the BOM.

Use the BOM from BOM section of the document, NOT the schematic. The Schematic in the document was used to develop the PCB in KiCad and it shows an Aleph 30 with an extra pair of MOSFETs. Again, The BOM part details are in the BOM sections of the build documents - refer to those sections.

So, I was looking around the Internet and I saw this interview of John Curl back in '99.

It is very interesting, specially when he starts to talk about the sound of components and the shortcomings on our measurement techniques... I believe every he says is valid today ( shhh... don't tell the folks at ASR... )... it's always refreshing to hear people who know things.

https://parasound.com/blogs/news/an-oldie-but-goodie-interview-with-john-curl

https://www.stereophile.com/content/linear-tube-audio-eastern-bay-sound
Scott Lindgren, Dave Dlugos, and Woden design all mentioned, nice to see in print! The speakers would fit well in a house with a nautical theme, I'm sure they deliver soundwise. The Woden logo can be clearly seen in one pic on the Eastern Bay's site. Congratulations.

US3983337A - Broad-band acoustic speaker
- Google Patents. Nothing but cubic money now to keep us from having a true 20-20 kHz point source driver. 😉

GM

I'm trying to understand how long these tail pair + VAS on the attached screenshot work together and got 2 questions so far:
1. Why one of the differential output signals is picked up from a CCS (the emitter of Q5225) instead of the collector of the 2nd transistor of the long tail pair (collector of Q5125)?
2. Why there's no resistor between the power supply rail and the collector of Q5125 similar to R5105? Doesn't it break the symmetry of the whole long tail pair?

I've been working on calibrating audio systems for so long and now this combination is truly something special to me.

I would like to offer help to anyone who would like to learn how to make use of these tools because all of them are free and they can replace a lot of very expensive hardware.

Here's a great example of that.

Using Equalizer APO, you can copy the L and R channel to other outputs on an 8 channel sound card. Then you can use REW to dial in the exact FR that you want and save those filter settings to a file. Then open rephase, import the measurement from REW and the filter settings. In rephase you can also correct the phase and set up crossovers for each channel. Save the impulse as a mono WAV and select that as the convolution filter in Equalizer APO and WHAM you've got an active crossover, linear phase system.

You can then remeasure that channel, create another filter to fine tune the response and load that into the next bank in rephase to make a more refined impulse file. You can repeat that enough times to make your frequency response look unbelievably smooth.

This system is superior to a lot of pro tools like Diraclive because for one thing, dirac live is practically useless for phase correction because you can only get accurate phase data at close range with lower volume levels. Rephase allows you to correct phase blind by inputting the crossover topology.

One of the best things about Equalizer APO's convolver is that it's suprisingly low latency.

I'm starting this thread to see what kinds of projects you all have going on using any of these amazing tools.

Hi guys I'm Looking for pics of circut board of a Profile california AP2000. Or circuit diagram if possible. I have an interminent turn off/on fail opened the amp and one resistor is burn and causing this just need to check specs on this resistor as it seem that someone already work on this amp an mixed 2 resistors in parallel and one in series to comply with the final load.

Hello, and thank you for accepting my request to be a part of this forum. I'm looking to learn about the interesting engineering that goes into creating speakers and audio technology. I'm hoping to at some point create my own speaker system, and i hope that this forum can be a big help!

Does anyone have knowledge and experience with EI e88CC made in Yugoslavia? Do you like it compared to Siemens or telefunken sound ?

In the mid 90s, I started to build PC based audio machines using WIndows and built in cards... then moved to Firewire... then moved to USB... but it always felt a little bit too much like a computer. (*)

I've been using Android tablets for quite a few years now as a streamer... with the USB OTG connection to a DAC. Running Tidal HiFi and FooBar... plays nicely. Usually I buy them at Costco when they go on sale for 200 bucks and I'll put in a 512FB sdCard into them. They do great for audio and are pretty good when I travel to get my email... ( hot spot my cell phone ).

But the hardware has a fatal flaw, IMHO, it only comes with a single USB port, so getting USB OTG and Power to work together at the same time is a crapshoot. Now, normally, a single charge should be good enough for ten hours or so of music, but it still bothers me. Also, sometimes I've ran into issues where the cable was borderline and the tablet would stop driving music to the DAC. Getting better cables seems to have solved the problem (knock on wood), and also newer tablets are more reliable (I'm running a one and a three year old -both Samsung).

So, I tried Raspbian with a Raspberry. It works great and it's actually more of DIY world, so it satisfies my needs nicely

BUT

It still a hassle, I wanted something that would not require me to make it look like it was a "computer" nor that ran into those pesky issues with USB OTG and power...

So, last May I got a Chromebook at Costco for 200 bucks... and I put a 1TB uSDCard in it. It has two USB-C connections and two USB-A ports as well... so I can charge it, use a remote mouse, connect via USB-OTG and the form factor is a little bit less obvious when I close the lid. I've also taken it to a couple of trips and It works quite well, having the keyboard makes it far easier to use for other tasks.... emailing is sure far easier than on a tablet/smart phone.

The Chromebook also runs dual ARM A7xx chips which makes them a bit better than even the latest Raspberry 5. Not up to par with the expensive Android tablets perhaps, but I don't run many applications.

The only downside with Chrome OS is that it wants my Google account password... I think I need to fix that when I get around to it.

I've been so happy, that I just bought another one today on the Black Friday sale.

I've been reading that it's quite easy to make them run as Linux machines (**)

So, for the time being, I'm moving to using Chrome OS as a music streamer, and will keep playing with Raspbian... but I don't know that I will play with the Android tablets much more.

What is your experience using these OS/platforms for music streaming?

(*) My home theater uses a Windows 10 laptop with an i7 to play DVDs and music. It can do Netflix, Foobar, VLC, etc... and it's hooked up via coax to a surround decoder AND via USB to an 8 channel DAC that drives the surround decoder via analog 7.1 as well. It works well but our latest smart TVs do Netflix and Plex so the laptop doesn't get the love it used to - unless I want to run the full 7.1 system. Hopefully my latest experiments with eARC will work, otherwise I might have to upgrade the surround decoder...

(**) I knew several people, developers, that for years have been buying Macbooks only to use them as Linux machines.

Does anyone have plans for a build similar to the Fern and Roby Raven utilising the SEAS FA22rcz 8" fullrange driver?

Looking to challenge myself and think these would be great fun to put together.

Any help would be very much appreciated.

I have a tube-based phono preamp with 787K resistors on the output RCA’s from signal to ground. I’m thinking of swapping out the RCA’s but I’ll probably end up butchering the resistors in the process; if I do, can I replace them with a 750K value? I’m sure I can, but maybe not.

https://www.theguardian.com/books/2022/nov/18/the-big-idea-why-does-music-have-such-a-hold-over-us

dave

This started as a curiosity for me in this thread on suitable replacement drivers for a small speaker similar to the LS5/3A. I decided to make a small sealed speaker of the same dimensions as the LS3/5A (12in tall x 7.5in wide x 6.5in deep) with a goal to reproduce the typical response that it so famous for - but using modest (inexpensive) and readily availble drivers. The Dayton RST28F-4 is a newer low cost but well built soft dome and the DC130A-8 is a coated paper 5.25in woofer that has a pretty smooth response.

Details on the construction of the speaker can be found here in the foamcore speaker thread. Basically 3/16in Elmer's brand foamcore sheets, doubled up on the baffle and braced. Noico mass loaded butyl damping applied om the inside aliong with melamine foam pads and grey eggcrate acoustic foam.

Here are some photos of the construction:






Here is the assembled speaker:


The measured raw responses of the drivers:


Here is first cut at the crossover (asymmetric Harsch-like with inverted tweeter):


Here is the XO implemented outside with Wago connectors:


Here are the Crossover Part Numbers from Parts Express (per speaker)

L4 = 5mH 18ga #275-141 qnty 1
L1 = 0.1mH 20ga #257-568 qnty 1
C2 = 4.7uF MKP #255-020 qnty 1
C3A = 10uF MKP #027-114 qnty 1
C3B = 1uF MKP #027-410 qnty 1
R2A, R4 = 12.5ohm #006-12.5 qnty 2
R2B = 1.0ohm #006-027-101 qnty 1

C3 = C3A+C3B
R2 = R2A+R2B

Here is the predicted frequency response:


For comparison, here is the measured response of a typical LS3/5A:


Here is the predicted impedance - very benign and nominally 7 to 8ohms with a 22ohm peak at box tuning:


Here is the measured frequency response of the XO - note the wiggle in summed values around the XO - results from the asymmetric slopes in a Harsch-like approach:


Edit 8/25/2020: I remeasured the freq response a few days later and applied 7cycle FDW to match closer the smoothing of the Stereophile data:


Here is the corresponding HD vs frequency at 0.5m and 2.0Vrms:


Here is the measured Step Response:


This is the measured system impedance with XO and inside the box:


Edit Oct 11, 2020 - Polar (horiz) frequency response measurements at 0.5m and 2.0Vrms:


I am just atartitng to listen to it.. nice sounding and very clear vocals. Will give update later once I have more time. But not a bad compact bookshelf using basic components.

3D CAD plans for 9mm BB ply version with beech battens and 12mm baffle to allow for rebates for flush front mounted drivers:




Edit Dev 5, 2020: wooden cabinets - called Rockville’s now finished and playing nicely. These speakers sound superb as near field monitors.


Crossover boards:


Back panel with name plate made (same as battens) from Civil War era white oak from a razed barn near Rockville Maryland.

Hi. I'm wondering if there's such a thing as a universal paralleling 'box' you can plug two identical mono amps into to lower impedance capability. G.A.S. aka James Bongiorno did produce a bridging box called "The Bridge" for bridging their amps which was a universal circuit. TIA

looking for some crossover design advice , will post thread soon

Howdy all,

I got an older console stereo system at a auction on a low bid. Its a smaller one. Has a turntable and a tuner. Would be nice to do some upgrades or perhaps just repairs.

Since this was basically free figured its a good place to learn, My electronics background is college level physics (just 100 level) and a little car audio, little RPi/Arduino. So when I look at the schematics on say the DIY chinese tube amp kits discussed here I recognise quite a bit of it.

Is there a good place to start to read about tube amplifiers and these old home stereo systems? I would like to be more up to speed than I am. Going to dig into the console next week see what is and isn't working. go from there! in the meantime need to update my circutry knowledge base.

Phil

Hi all,

I recently found some Lithium Titanate (LTO) batteries on ebay and thinking that they can be used for 5 VDC DAC or ADC supplies I'd just like to mention it here.

The batteries nominally are 2.9 AH/2.4 VDC (3 AH) versions, however, their discharge curve voltages start around 2.5 to 2.7 volts. See e.g. here (larger capacity battery):

lithium & solar power LiFePO4 : Photo

According to a measurement the seller has emailed me these batteries may have an internal impedance as low as 1 milliohm (see first attached image). When discharged through a clamp at a 10A rate the combined impedance of the clamp/wires + battery is about 9 milliohms (second image & third image).

Additionally, to my knowledge the lifespan for LTO cells can be very long - many thousand charge/discharge cycles.

A link to the ebay ad is here:

Toshiba 2 4V 3Ah Lithium Titanate Li ion LTO Battery Cell 180 Amps Current | eBay

For a bit more information on these cells Toshiba lists some information on their webpages:

“ŒŽÅ‚Ì“ñŽŸ“d’r SCiB�b2.9AhƒZƒ‹

The European EV/GWL company also has posted some measurements on LTO cells (another brand though) which can be found here:

lithium & solar power LiFePO4

As far as I can see LTO cells can be charged as a normal Li-ion battery when observing their lower voltages.

FYI in case it may be of interest to others here ...

Cheers 😉

Jesper

Hello from the multiway section. This is my first time in another section of this forum.

As the title states I want your opinion. Data also accepted. Distortion measurements appreciated

Check out the pictures. What I am created is a ribbon tweet, planar mid, woofer studio monitor for my office. Ultra low distortion is my aim. I was hoping to find a driver to play from 800-40 hz at the bottom end. Beyond 40 I don't care much as I can't hear any lower than that and it won't play at an SPL level I would be able to feel. I have 0.38" cubed to play with. I can make the port as long as I want. Maximum diameter 7".

Other option is to seal up the woofer and try to integrate a subwoofer. In which case I would run a big cone. Probably a 15" sealed. Or make a ripole. Or make a push push. Not sure yet.....

Here's my options really:

1. Run an Epique 5.5 as my woofer. Run it from 800-38. Make the stand of this build the large port necessary to run this. Call it a day.
Cons of this (there are always cons): I've seen only one distortion measurement of this driver and it sits around 1-1.5%. The other drivers in this build hang out under 0.5%, nearer to 0.2%. This is going to make the woofer the driving factor of distortion. Additionally I would now have low frequencies shaking the mid and tweeter. I suppose a push push would make that go away but then I have double enclosure space to deal with....

2. Run a low distortion driver like the SB Acoustics Ceramic 6" and seal her up. That rolls off around 100 hz. Then I run a sub and attempt to integrate it. I've tried this with friends subs and it never quite matches their monitors correctly when changing volume (I have a lot of musician friends). It is VERY possible I just have no idea how to do it properly. In which case, I'd love if you'd point me towards something that explains the proper way to do it. Or just tell me. Either is fine. I'd run a big cone sub or fiddle with a ripole for fun.

3. Some other option or driver I am unaware of but you know about and want to tell me about.

I'll attach a couple of the simulated XOs (everything but the woofer is real measured data, the woofer is traced data) and a picture of the current enclosure design which is subject to change. The low end is not reflected in the XO currently.

Let me know your thoughts you beautiful bass heads!

I have two of these lovely chips.

€150 + shipping at cost.

R

Hello,

All in the tittle,

I have a DVM (6000 taps) but looking for an easy tool to say if a fet/mosfet/BJT is dead (littles as well as power transistors), and also give the numbers for good matching enough.

For now I try to test Fet with the buzz continituiy of my DVM : when going to buz with fast intermittent way : Fet OKAY ; If continous : FET bad ; I did it with J113, seems reliable.

But would likee something more easy and also sort out.

I know some cheap known tools, but have heard only bad things about it... At last some seems easy with smd pads and so on.... Gadgets ? I am only DIY casual...

Thanks

I haven't posted on here for many years, i've tried to reply to a thread but it says new members must introduce themselves first, so here it is 😂

Hi everyone 😊

Howdy!

I have had a Sony DVP-S9000ES for a couple of years now. It's really great sounding player for red book discs. Ever since I have owned it, it has had the problem recognizing the SACD layer of hybrid CD/SACD discs. I wasn't terribly bothered since I have so few SACD discs. Fast forward to about a month ago and it started having trouble recognizing red book discs as well.

I tried various things such as cleaning the lens with isopropyl alcohol and running through the calibration menu for both CD and SACD discs. Neither seemed to resolve the problem.

I took the plunge last week and bought a replacement laser from eBay from a US seller called Liberty Electronics. It arrived to me on Monday and I began the process of installing it.

I finally got the unit back together on Tuesday and it's now having some severe troubles. I can't get it to recognize any disc, but one DVD that I tried. No CD or SACD. I tried the calibration procedure again and it failed on every disc I tried.

When I insert the disc, it will spin up and then I hear/see the laser unit moving forward in progressive increments. It gets all the way to the end of the CD and then throws an error that just says "Error". I can clearly see the laser is shining as well.

I removed the anti-static solder blob on the laser before reinstalling so I know that is not the issue. Unless I bungled that somehow, but do not believe I did using my Hakko de-soldering station.

Just curious if anyone has encountered this before and what the problem might be. Damaged laser? Incompatible laser? Incorrect reassembly or possibly something damaged during reassembly?

I've read that the unit might need to be calibrated, but haven't found a ton of info on how to do that just yet. Also read that the laser's gain might need to be adjusted but I haven't found those adjustment points just yet either.

Any help you can provide would be appreciated. I've been spinning my wheels the past few evenings but still not ready to throw in the towel.

Hi all,

I purchased a ported enclosure of full range Philips AD12100/M4 drivers recently. The enclosure was 36" x 14" x 18" (Height x Width x Depth). Unfortunately that was too big for my room so I started putting them horizontally such that it would lay 36" along the ground the be 14" high up.

I recently read that these drivers were good candidates for an open baffle conversion so I've simply removed the body behind the speakers and placed them at an angle, slightly toed in as well as inclined towards ear height. This is obviously a starting point and I'd definitely "do it right" if this is the right way to go (remove ports on the baffle, fix the toe in and inclination angles, wall dampening, etc).

Currently I feel that whilst the clarity has improved significantly there is a perceptible drop in "body" when playing music, something that I'm trying to compensate with my subwoofer.

I was wondering if there is anything I can do to my setup to better improve it given the inherent limitations present in my room.

I paid about $100 shipped. I will accept the best reasonable offer. Untouched , includes build instructions and matching resisters.

Hello guys,

I am diving into the audio world as I would be interested to add a Surround/ Dolby Atmos to my living room.

I am trying to avoid wires and thus look into what could be done DIY & Wireless. Unfortunately, it seems that there is not many reliable protocols that are able to achieve bandwith & latency requirements of high quality audio.

Dolby Atmos FlexConnect -> Almost brand new, not much info.

Bluetooth -> Quickly read that it will not achieve latency requirements ?

RadioFrequency -> Have not look into that.

And finally, there is WiSA that is a proprietary protocol using 5.2-5.8Ghz frequency - One person seems to recently look into retro-engineer this protocol so it can be used for DIY, but not much news: Build a WISA receiver.
After researching a bit everywhere, I might have found a way to buy the WiSA transmitter and receivers without buying in bulk. I will not post the link yet as I would prefer to try first and update you later (but if you are really interested, please contact me in private message.)

In term of hardware, the idea would be:

INPUT & TX:
- A 2nd hand WiSA SoundSend that has the advantage to be Dolby certified OR from an eArc HDMI Audio extractor with I2S output to the WiSA transmitter.
(I also saw the Orange Pi5 has en eArc HDMI but I did not find any active project on that + the Dolby stuff would still be problematic if I understood correctly?)
- Transmit using a WiSA TX board.

RX:
- a WiSA RX board has I2S & I2C outputs and thus could be use to a mini amp / DSP ? This is where I need your expertise !
HDMI Extractor ---I2S---->TX --Wireless--> RX --- I2S---> Amp/DSP? ---> Speakers.

Pin out is just for schematics

One of my concern is how usable is the RX I2S output as it could be encrypted. After long research, I do not believe it is (see schema of a WiSA DAC and a WiSA ready Amp that used to be sold) but only real test will tell.
WiSA DAC:


Looking forward for your feedback,

I probably have a better chance of winning the lottery but no harm in asking 😁

Michael here ,. Love the old school Voigt transmission design. Huge easy ways to deminish driver misbehavure. Less xover parts or usually none if single driver. Lots of good ones now! Forget phase alignment and xover complications. The quarter wave "tube" design eliviates fr peaks and valleys by canceling them out instead of excentuation them in some designs. Then they add expensive xoverer to cover up but often loose good qualities also. Awsome video on YouTube "worlds second best speaker" explains everything by a really smart engineer. I made a pair and they are really easy to build. This design has very good bass but the best thing is a very "airy and open" soundstage.. they surprised me even with cheap drivers. I have made all sorts of "made up" designs , some crazy, but this is what I will always experiment with. I put a long thin port at the very top that made a huge difference in opening these up and got rid of the confined boxed in sound we all have come to get used to. Look at video and see what you think.. Im a convert! Michael marmarasmichael@gmail.com

Hi guys,
I purchased a Cary SLP 90 clone board sadly with no further instructions. In two of the videos of the ready made SLP 90 I could make out the transformer markings as
220 v AC secondaries which I find very high for the 12AU7. Max rating for this tube is with most manufacturers about 330v DC.

Two questions: will the lifespan of the tube suffer with this high voltage?
If so can the circuitry stay the same for a reduced plate voltage?

I tried to get the schematic but was unsuccessful so far.

Klaus