Hi all,
I have recently replaced the VU meter lamps on my P5000 but the new ones are rather dim.
I measured the old lamps on a variac set to 12V and they drew 175mA each and so I ordered 12V/150mA replacements but as said, they turned out to be quite a bit darker.
Not sure what I am missing, I do have the service manual (it's available online) but there are no part values shown besides Accuphase part number.

+++
Ok, measured 18.9VAC on the lamp rail, considering the lamps are in series by 3, that would mean they are 6-6.3V parts.

The question rises up when a friend was looking for various new power amplifier devices and had serious doubts about the lifetime and reliability of Class-D variants when he saw the modules inside the devices, the images of which I uploaded.

What experience is there here?
Do the electrolytic capacitors have to be replaced early - i.e. after a short period of use?
Or can one assume a similar life expectancy for the well-known brands as for good conventional variants in analog technology (mostly Class AB) ?

At first glance the used electrolytics are in the same kind and same price class as in PC main boards and cheap SMPS modules - go to
https://hackaday.com/2019/04/12/ask-hackaday-experiences-with-capacitor-failure/ (nichicon)
https://de.m.wikipedia.org/wiki/Datei:Al-Elko-bad-caps-Wiki-07-02-17.jpg (GSC)
https://www.robotroom.com/Faulty-Capacitors-1.html (CapXon)
Thanks for comments.

P.S.: Interesting report
https://audioxpress.com/article/fre...-amplifier-module-doubling-down-on-a-flagship
https://www.audiosciencereview.com/forum/index.php?threads/nad-m23.30114/
https://www.audiosciencereview.com/...purifi-eigentakt-is-my-dream-amplifier.25376/

Hi folks,
I am looking to replace my existing full range 6 inches (dainty speakers, may not be a familiar brand to all) with either of the below options:

Cuboid 6 from Optimal audio
(https://optimal-audio.co.uk/products/loudspeakers/cuboid/cuboid-6/)

Flex point FP6 from Martin Audio
(https://martin-audio.com/products/loudspeakers/fp6)

Please suggest based on your experience whether this will enhance my surround channel experience or am I better off to look at something like the below which is meant for home audio

https://www.tagaharmony.com/en/products/3589/speakers/product/9131/platinum-s-100-v-4

Room size - 20x20
Source - Marantz SR5013

Dear Forum,

I know this is way too remote question to ask, but I found out that one of the blocks runs hotter, than the another however they sounds balanced to me.
I am using them with a Martin Logan CLSII pair.

Should I do the ,,biasing" as shown in the manual? Could this be that any of the 2SC2238B or 2SC3852's killed in action?

Thank you for your answer in advance!

Comparisons of focusrite 2i2 gen4 with generation 3 and other usb, firewire audio interfaces. Mdat you can find more here: https://drive.google.com/drive/fold...QRqwCC0mRVaoLX3O?dmr=1&ec=wgc-drive-hero-goto

Looking for a few 12" subs as I have a McIntosh Mc 2500 (did 735w from 10-100000 hz into % .001 THD @ 8 ohms both channels driven) that I would be using to drive them. I'm not concerned with the ohmic load as the amp is capable of 1 ohm if need be. I'd like for them to be in a sealed box and I'm happy to build it myself. I'd be using them for everything below 75- 80 Hz and would love if they would do 15-20 Hz on the low end. I'm not too concerned with total SPL, but 100 DB @ 20 Hz is a goal. Any recommendations?

Hello! I'm looking to make some very small, budget speakers as part of a 2.1 system for use with the TV. I'm very limited on space and will likely need to angle the pair and house at least one near a wall due to the TV being in the corner between a window and a fireplace.

Something like the nScan-Ken would be perfect, though it wouldn't necessarily need to be quite that miniature, but the £100 per driver cost puts me off.

I recently (poorly) made a pair of µMar-KenPlus and these are likely a little too big (though objectively small) and normally live in the dining room anyway. Photo is attached, for reference. Previously made a 2-way set using SB drivers based on a Troels design (with adjustments) but they were comparatively enormous.

I've been looking at the CHN-50P as a potential cheap and cheerful driver, but most of the plans I've found are larger than I'd want and I'm not sure if I could just "make them smaller" and lose some bass (as a simplification).

Any sage advice? Am I overthinking this? Maybe underthinking (and not doing any heavy lifting in terms of modelling a cabinet myself)?

Hello everyone,
Few days ago I just bought a chaniess PCB which basic schematic is something like that (attached).
Due to my poor circuit calculation skills, I assume that the zener(15V) regulator is currently delivering 9mA.

I would like to know:
1. Should I keep the 15V zener regulator?
2. Does the 15V zener ok for RMS 28V?
3. Is it possible to add a potentiometer (shown in the red-colored box, R5 + 5K POD) to adjust DC offset?
4. Will I get any advantage if I replace the Zener with LTP (as shown in the red-colored box)?

Thank you. I would appreciate your valuable advice and opinions. 🙂

Hi all,
This is Andrea from AAElectronics (https://www.aaelectronicspcb.com/). After a lot of request, I've started design for a PCB for Vox AC30 style amps, with the aim to make it flexible enough to accommodate seevral variants (e.g., EF86 channel, Normal, the AC15 version or additional mods). I'll attach the layout, PCB, and schematic for reference.

Would love to get your input on my design, and whether you'd like to see/add something to the PCB/schematic.
Have a great weekend!
Andrea
AA Electronics

Hi all, looking at changing my alps pot to a tkd.
As per attached pdf. Assume 1 in input 2 is output and c is earth?
First time at this, so just need a little guidance.
Thanks.

Ps. Worthwhile upgrade?

How can a transformer 2x175VAC produce 200VDC after rectifying?
It is a mystery to me.
What is the way to calculate such a Supply? Coefficient?

I tried posting a thread to ask a question about a DIY speaker project, but the site won’t allow me to post. It is telling me I must post here first.

I’d like to put together something like the An-e speakers. Does anyone here have experience with this? Cabinet build plans?

I’d also like to know if anyone might be local to NYC who could lend a hand, as I am disabled. Does anyone know any speaker builders who do this kind of work? Seas a24re4 and Morel Cat378 seem to be popular for Audio Note-inspired builds. Please let me know. Thank you.

Opened an account here to be able to post my condolences for Carl Huff who I can see has been an active member. Carl and I were close high school buddies who managed to fall out of touch with each other for decades. Please don't let that happen to you - keep in touch with your friends.

Hello,

Thank you for accepting me into the forum—I’m really excited to be a part of this community! I started my journey in speaker building about a year ago. At first, I didn’t have many resources to learn from, aside from YouTube and a few websites. However, after my last box design turned into a bit of a fiasco, I realized that everyone who said, “It’s not that simple,” was absolutely right. It’s much more complex than I initially thought.

I’m hoping this community can help me find answers to the countless questions that keep popping up as I continue learning and improving.

Looking forward to engaging with all of you!

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.

Hello all,

I have some Dixson Inc VU Meters from a Quad Eight Mixing Console for sale

Genuine & original parts date from early 1979, Made in USA

Meters measures 90mm x 71mm x 55mm deep

Complete with bezel (97.5mm x 57.5mm) & mounting hardware

Requires a 94mm x 54mm panel cutout for the bezel

Supplied with brand new Type 53 14V lamps

Perfect for vintage gear restoration

Have five (x5) of these available

I'm thinking USD 50 each plus postage or open to offers

Cheers, Ralph

https://audiofile.net.au/

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 some Harbuch 600 ohm line input transformers for sale

These transformers are high quality, Mu-metal shielded, stud mounted units intended for line input applications and have center-tapped 600 ohm primary and 600 ohm secondary windings

Pulls from a mixing console

The leads are approximately 150mm long

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

Cheers, Ralph

https://audiofile.net.au/

Hello all,

I have a quad (x4) of NOS 600 ohm line transformers for sale

Made by Control Dynamics, part number is CD1119

These transformers are intended for telecoms, voice-frequency applications and have center-tapped 600 ohm primary and secondary windings on an ungapped ferrite core

They measure approx 16mm cube

I'm thinking USD 10 for lot plus postage or open to offers

Cheers, Ralph

https://audiofile.net.au/

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

Hello all,

I have a pair (x2) of NOS Cannon EP3 Male 3-Pin Connectors for sale, still in their original packaging!

Full part number is EP3-12-1C

I'm thinking USD 20 each 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.

Hi Everyone, My name is Bill and I own Mnpctech in Minnesota. We are a small family owned workshop and online retailer.

I started out in 2001 making custom accessories for people who build and modify desktop PCs. Two years ago I started expanding into custom replacement and isolation feet for Turntables. I've had one blip of notoriety when Michael Fremer said he preferred my custom Sorbothane feet over Technics factory foot design. (Stereophile (november 2018, technics SR-1000 article) I'm Currently working on new height adjustable leveling foot design, isolation platform for TTs and speaker stands. A lot of my sales have been to people restoring vintage turntables.




If you have Turntable Custom Replacement Feet Inquiries:

Help me with following details and photos.

1. Turntable Brand & Model

2. Photo of Foot, top & bottom

3. Mounting Screw measurement (thread size and length)

4. Photo of turntable bottom showing how the foot attaches.

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

Looks like it's about to come out
https://www.parts-express.com/Dayto...ure-Series-Woofer-80W-Driver-4-Ohm?quantity=1

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 ?