I’m going to convert the 2-way to 3-way speakers. The 2-way consists of a 10” woofer and a 1” tweeter per cabinet. I’m reluctant to choose midrange drivers for my project. There are two choices for me:

A ) 1.5” dome drivers with ferrofluid cooling, 4-Ohms DCR


B) 2” dome drivers with air cooling, 6-Ohms DCR


The two choices are in the same series and receive the same technologies according to the descriptions.

The operating range for the midranges is estimated approximately 750Hz to 3.5kHz (with second-order slopes).

Assume all other properties are identical i.e. sensitivity, distortion, frequency response, and cost, which MF driver is more preferred, in your opinion?

Here's a few driver distortion measurements I made today

These aren't terribly scientific, but if they help someone out, cool! I just set my amp to -3dB and measured each driver at the same amplifier level, which isn't necessarily the same SPL level because the impedance of these drivers is all over the map

I used a 15Hz highpass and a 120Hz lowpass, both LR4

I used no baffle; this is just the raw driver

First one up is a measurement of a twelve inch Infinity woofer from the Infinity Prelude speaker. These are readily found on Craigslist for a few hundred bucks. I trashed mine (all of the mids and midbasses had surrounds that were trashed) but was pleasantly surprised by how capable the subwoofers are, despite looking fairly pedestrian

Hi
I have a WADIA 12 that was plugged in with incorrect input voltage and the transformer got damaged. I really like the sound of the DAC and would like to fix it is possible. Does anyone has the transformer specs for it? The transformer is marked as EL48/16.8 10 VA. I found some suitable ones but need to know secondary voltages. If someone that has a working unit can measure the secondary voltages would be much appreciated. Looked everywhere for the schematics without any luck.

Thank you

Watch the full Reel Here!


https://www.facebook.com/HoltonPrecisionAudio/

Hi All, I live in Western Canada and for the last few years have been repairing vintage audio gear. Every once in a while I get in a bind and look to the audio community for their support in working through issues. I’ve had a couple hundred units on the bench so far and have a passion for Sansui gear. Daily driver a Sansui 8080, 555a as secondary setup and a 666 in the kids room. Ones I wished I’d kept…7070, 2000X.
Cheers,
D

Hi all, looking at the circuit of the Neumann WV2 phono stage, I ran into some inconsistencies..... The circuit has an input transformer 1:50, gain stage EF804S (triode connected), a second gain stage with EF804S and RIAA section as a feedback circuit around it, then another gain stage with E80CC, and a fourth gain stage with another E80CC and feedback, then an output transformer 10:1.

When looking at the operating conditions (very low current), and calculating the gain of the different stages, the total gain including everything ends up at a whopping 91dB @ 1kHz:
input transformer +26dB
first gain stage +30dB (using the values from the datasheet)
RIAA stage +15dB (at 1kHz) (again, using datasheet values)
third gain stage +20dB
fourth gain stage +15dB
output transformer -14dB (output is symmetrical)

The simulation kind of confirms those values, with some dB of differences, most likely due to the tubes being operated at very low plate current and the tube model may or may not be very accurate in that area. (I used a 6922 in place of the E80CC).

The description of the phono stage is talking about a gain of 70dB (with input transformer in ) or 50dB (without), which is quite a difference.

Anybody has a good idea where that big difference is coming from?

The Person:
Hi to you, my new masters!
I've had an interest in HiFi for a lot of years, but the money have been prioritized elsewhere.
Not new to electronics in general and have a basic understanding in how all this works.
This is my first tear down however, and attempt to repair an amplifier so I need someone to hold my hand through this.
I'm from Sweden and lives in Gothenburg, which can be good to know when recommending components.

The Problem:
My NAD C372 have been in my possession for its last 7 years.
When I bought it it made a low noise, like tearing cloth slowly, when cold.
After like 5 minutes it was completely gone.
Now it never goes away. Always there, lurking in the silence.

The Mission:
I hope to get some guidance not only to fix this amp, but to upgrade it too.
Budget is hard to say when I don´t know what to change and to what yet, but let's say 150€-200€.
I´ll try to take pictures on things as I go, not only to make it easier for others to follow but because it's a lot more fun to read posts with pictures in them.
With a good help from you this can serve as a guide for future DIYers, with my lack of skill it can serve as a warning.
Let's hit it and see how it turns out!

We'll start with the Main Board and the PSU. Later on I want to have a look at the Amplifier boards.



My first approach was to open it up and look for leaking or bulging caps.
I found a lot of brown gunk around 4 bigger caps (bulk caps for rail B and C: C734, C735, C748, C749).
Since the noise is in both channels, the PSU seems like a plausible source of the noise in my noob head.
This is where it all started. Sourcing caps and info on what kind of caps I needed, aka opening Pandoras box...
I had a lot of problem with the small footprints and the 105C rating. The C372 is known for running hot so no 85C for me please.
Most HiFi-caps were too big since rail B and C clearly was designed by some engineer sharing closet with his wife,
while the main rail A was designed by previous mentioned wife.
After 3 days and 2 nights without sleep I ordered the best I've found:

2 x Vishay 2200uf 50V 105C with 7,5mm pitch (part# 2222 048 61222)
2 x Nippon Chemi-Con 1000uf 160V 105C with 10mm pitch (part# EKMQ161VSN102MP40S)
Cost: 20€

This is where I couldn´t help myself. I took another look into that box and soon realized that it's more fun to upgrade something than to repair it.
Invest money instead of just spending it so to speak.
I have no idea if these caps will solve my problem since it could be more bad caps.
I've also learned that not all caps bulge when they're bad, and that the brown stuff might be glue.
My idea here is to change most/all of the electrolyte caps (all branded Jinghai) to newer and better ones since they're all old.
(Are Jinghai good btw? In the computer world Chinese caps are not that welcome...)


We'll take a break here for some questions before looking at what to do with the main rail.

Any idea if I'm on the right path to solve the main issue, or do you think it´s something else?
Is it a good idea to spend money on upgrades, or should I first try to fix it first to be sure if it´s worth it?
Do I need to change other caps than the electrolytes, or does the film-types age better?
Should I change the film-types anyway for better sound?
Piggyback small somewhat high-end caps to cheaper filtering caps to keep cost down or get smoother power, like a 0,220uF in parallel to C746 and C747 in C for example?

Hope you will join me in this one!

/F

I have two pairs of Mesmerize PCBs still in their envelopes from DIYAudio.
And one pair of F-5 turbo boards
$10 each + postage.

For sale: Pair of Peerless/Precision TX-255F 10" woofers, from the 1980s.





Gray poly cone, new foam surrounds. Work perfectly. Great sealed box, infinite baffle, or open baffle driver. Here's the specs:



(BTW: These specs are in metric measurements. VAS is in cubic meters- multiply by 1000 for liters.)

Selling for $65.00 for the pair, plus shipping.

I don't have Paypal- I usually work with USPS postal money orders. US shipping only.

Thanks!

Regards,
Gordon.

Due to some recent life events, I no longer have the means to make a DIY speaker myself. However, I would still very much like to make a speaker, or at the very least, participate in it's design and construction. So I need a builder.

Yes you will be compensated accordingly.

I want to build a set of active MTM monitors with side firing subwoofers. Traditional materials are always an option, but am open to other methods like 3d printing (provided cost be about the same to a little extra). I would also like to be able to put these on stands/tripods/etc.

Please contact me via the ad here and we can discuss the details further.

Hello again!

I am doing some maintenance (and some upgrades) to my Mosvalve 500 power amp, and one of the things I'd like to address is the captive cable at the rear of the unit, obviously used to power it up. I was thinking of creating space for a standard IEC receptacle, but I don't know the best way of going about it, so I've decided to come here for help. I don't actually have a router, and I want to know how stupid an idea it would be to use HSS drill bits and a drill to get the shape most of the way there and just file out the rest.

Thanks in advance!

See picture for my filter.

I think this is about as close as I want to place all my components. Originally I wanted all of this to go in that black plate to the left. Clearly, it will not all fit in there. That is the back panel to my enclosure, the side you see is the INSIDE of the cabinet.

I am considering externally mounting this. Just 3d printing a standing plate where I can mount them all to it.

Anyone have any opinions on external VS internal mount? Any way I can smoosh all these onto that plate without the inductors wreaking havoc with the other inductors and/or caps?

Hello. I have a fault in my power tubes heater wiring please. There are 6 tubes in line 6550 spaced around 12 inch from first to the last. A solid AWG 17 was used to do a twisted heaters line. The average curent from the first tube to the last one is 8A around. Still I recorded 35mV loss in one wire and 47mV in the other from the first tube to the last one (It was supposed to be identical but I used wires from two different batch from colour reason and are not identical for same length). Well... I know why I did it wrong now but because everything was well posed and built I looking for a quick solution to fix it. And the first thing was going through my mind is to run an additional twisted pair from the first tube directly to the last. I called it "compensation line" marked in red on my sketch. Please take a look on my drawing and let me know if it work please. Thanks.

Hi,

I want to choose a 15 inch driver for small sealed box (30 liters). Can you please suggest what technical parameters I should be looking for?
I plan to use a small box, equalize using LT and use a higher power about 600 watts.

Note:-I understand Hoffman Iron law.

Thanks and Regards,
WA

Hello, I´m a member since 2019 but never post anything... About a month ago I was looking for info about sweep tubes and found the the "red board engineer's amp" thread and read it all. Very good reading and a lot of laughing moments thanks to George ( tube_lab.com )!

I've seen a mod for the crescendo from 1982 where a 0.5mm2 wire is soldered on the bigger traces.
Was there a problem with th original PCB layout and what if the PCB layout was okay, what is the benefit of this mod?

Hi friends,

Thank you for your patience as I theorize again. I realized as I was looking at others discuss Synergy horns how little I know about horns and that some of my musings may have an answer already in terms of the physics. As you may remember I'm often wondering about how good a line array using a single driver type in a single line could be. Some of the most respected line arrays use multiple driver types for different frequency ranges so I'm trying to ask how we could push 4" drivers to wider horizontal dispersion.

At some random time I was also reading about the Doppler effect in large, wide band drivers as well. I had been thinking that maybe turning a line source sideways and slot loading it could solve a lot of issues at once:

• Eliminate Doppler/IM distortion by listening at 90 degrees to the piston
• Improve horizontal dispersion compared to using a front facing full range driver by using a relatively narrow exit slot, say 1"

Then to my surprise Monitor Audio did something very close with a concept speaker. The full speaker is a 3-way with separate mid/treble section but look at how they do the bass section. The two towers below are part of a single speaker:



So I guess before I even go very far, what are the physics of the slot? I mean, say I design a line array along these concepts. Two line arrays of 4" wide band drivers facing each other but 1" apart. Assuming the drivers could get to 20kHz on axis, what are the physics of the response when loaded essentially by a slot, as seen above?? Am I even going to get any treble at all? Is this essentially a very short horn?

Thanks!!

Erik

Hello everyone. Avid home theatre guy, avid music guy and I want to dabble in car audio. I am going to post a drawing of a sub enclosure I want to build for my 91 Cougar XR7 with 2 JL Audio 12W0V3-4 drivers....but first I have to introduce myself. Well, here I am..old guy from Manitoba, Canada interested in building speakers..first things first, a sub box for my old car. Thanks for having me, looking forward to learning a thing or two.
Cheers!
James

One pair used but in good condition from revelator series.6,5" passive radiator.Price 100 euro(or best offer) plus 14,90 euro shipping inside EU!

Looking over driver specs, I see that woofers can have straight, exponential, and radial cones. What is each profile for or optimized for?

Edit: What is a radial cone?

I'm talking about a closed enclosure subwoofer. Traditionally, most people choose to build an enclosure with Qtc of 0.707 or Butterworth characteristic. I wonder what if I build the sub in other alignments. Two following choices are selected for comparison: Qtc of 0.5 and 1.0.

Has anybody ever heard the same drive unit in those two different alignments, Qtc = 0.5 and 1.0? How would you describe the difference of sound between them?

Finally, which one do you prefer?

Cast aluminum frames, alnico magnets. Excellent condition. See current production of this model at greatplainsacoustics.com.
They retail at $1230 each.
$400 plus shipping for the pair.
Thanks for looking.

I used to be an audio tube dealer. Had 1000s of NOS tubes. Thus I heard every 12AX7 ever made. The best vintage IMO is the Mullard long plate 12AX7 However I was stunned when I tried a JJ E83CC. The JJ sounds very similar to the Mullard but projects much further into the room and the speakers just disappear. Try the JJ, you will tank me later. My amp is modified with best parts and crystal clear audio. Many amps will not perform well enough to hear large differences in tubes.

The Tubes Store has these tubes for $27.95 each. Bargain!

Searching service manual for a NAD PP 4
How could someone check what is on this page? NAD PP 4

Lightly used, about 5yrs old. €380 + shipping to Europe.

The cartridge has been installed only to verify correct operation. Soundsmith did a great job. Cantilever is right in the middle and aligned with the cartridge sides making setup easy and painless.
Ruby Cantilever / Optimized Contour Nude Contact Line Diamond stylus.

€800 including shipping within EU.

For sale are 2 unassembled MyrRef amp PCBs. The boards are version 1.05 circa May 2013. I only have parts for 1 board. As can be seen in the photos, I'm including all the parts I originally purchased from Mouser, and I'm reasonably confident most of the parts (99%) are there. The parts have been organized by type in individual plastic bags. The parts bags may include more parts than required. I did not go back and open every bag and count the parts. There may be a part or 2 missing, so please don't hold that a against me. 🙂

This sale is for the amp PCBs and parts for 1 only as pictured.

I'm asking $125.00 for everything as shown in the photos via Paypal, with free Priority Mail shipping in the US only.

Please PM me if you're interested and want more detail.

Rick

Good evening all,

I'm looking for a replacement tweeter for a recently bought pair of TDL Monitors. The models fitted are 25DT61's. I already have a pair which are fitted with 25DT31's so the 61's are probably not common.

Regards

Richard

Hello hello from sunny Singapore

My problem is multifacetet, but I think chipamp category fits best. I have a work laptop as a source and I used a pair of small DIY 4" full-range speakers for Teams and background music. I've been powering them with a small, single TPA3116 based amp. I occasionally use this amp to power other speakers, including experimental DML speakers, and there it clearly runs out of power. I've been planning on adding a dsp unit, which would require even more power if boosting bass. In my case I cannot use the source computer as software DSP, it must be an independent device.

Right now I have unemployed Raspberry Pi 4B and a Zero 2 W, both of which have more than enough CPU to run a few filters. But what should I hook them down to? There are a few options.

Raspberry Pi Zero 2 W

• Has only one usable USB port and it must go to the source computer. The other port is for decoration only (or power, but so it the first port).
• Can be powered through the source USB port or through a hat.
• Output is limited to hats, because of the USB port configurations. A DAC or an integrated amplifier hat.
• Small and runs cool.

Raspberry Pi 4B

• One usable USB-OTG port for source. Hosts 4 USB ports for output.
• Needs external power supply or can be powered through the hat. The current draw is too big for powering only through the source USB host. USB 3.0 is rated for 900 mA, with my computer it works, but the system was not that stable. It also takes under-clocking to reduce power draw.
  • To use the only USB-OTG port for powering and connection, it takes a power-data split cable, USB-C power source, a USB power blocker to protect the source, a power switch on USB cable (optional) and a few USB cables for covering distance.
• Output can be set to hat or one of hosted USB ports.
• 4B runs too hot for my liking. Even when under-clocked to minimum.

Using separate amp (a more powerful chip amp)

• RPi 4B with USB DAC works.
• Either RPi model with DAC hat works.
• The number of power adapters and wire-pain increases.
• Takes more desktop space.

Using Raspberry Pi with an amp hat

• Either RPi model works.
• Can be powered though the hat, makes wire management easier.
• Options for hats are very limited and often low-powered and use not-so-great chips. Most probably one of Hifiberry amps would be my choice.
  • The problem is that there is very little data, reviews or shared experiences about these devices. Are people using them "happily ever after" or did they end up in recycling them?

Using Raspberry Pi with separate I2S device

• Not pretty, but would satisfy the tech geek side of me 🙃
• The only considerable options that I've found are the JAB5 and it's Dayton copy KABD-4100.
  • Same problems as with amp hats.
  • It's got it's own DSP, but no other form of lossless digital input.

I have already tested out both of my RPi (Zero doesn't have output device yet) as DSP processor with CamillaDSP and that works very well for my use. The USB-OTG port (on-the-go) is mandatory for connecting the thing to a PC and allowing audio to be streamed via standard USB 2.0 Audio Codec (UAC2). Bluetooth is unacceptable connection in Teams meetings because of the half-sec sleep timer. It makes conversations almost impossible with my current BT devices. I'd rather keep a wired connection.

Now bear in mind that even thou this is very low-fi system for very low-fi requirements, I value good performance and would like to have a unit that's capable to run some more demanding speakers when traveling to the lake side on holidays. I'm budget aware, but not budget limited. I'd like to keep price of new purchases at or less than 150 € unless there is a very good reason to spend more. I'm open to consider any reasonable suggestions. I'm mostly contemplating between Hifiberry amp and going to buy a more powerful chipamp with a cheap DAC hat for the Zero or use the 4B with USB dongle DAC that I have.

I have here a full set of clone PCB's to make 1 complete Yamamoto YDA-01B DAC. It is based upon the CS8416 transceiver, PCM1794A d/a chip and x2 WE403B tubes as part of the I/V stage.

I will send BOM, Sch. etc after full payment is received.

You have to bring your own components and assemble.

Asking price is $110 / €110 incl shipping world wide. If you use PayPal remember to add fee since this is not included.

Oneminde

New (NOS) Analog Devices AD745KN FET Opamp from a bonafide USA distributor. 8DIP package. 1997 datecode. Still an excellent performing opamp for MM phono preamps or ADCOM GFP-565 preamplifier upgrade (with appropriate capacitor and resistor changes). Selling off old shop inventory. 34 available. USA sale only. No international shipping is available. Send pm if interested.

I have a Plinius M8 and the remote control works only occasionally.

Apparently Plinius uses standard RC-5 codes, apart from mute - which is actually the main problem because when you turn it on with the switch at the back it comes on muted.

I have a list of the RC-5 codes, but I'm struggling to find a programmable remote - they mostly seem to be "learning" ones, where you point the old remote at it and press the button, which is only good if the original remote is working.

Can anyone recommend a universal-type remote that allows you to type in the codes to allocate to the buttons? I know that there's an RCA one, but that only seems to be available from the states with £40 postage.

Hi guys,

Bought an Levinson ML3 amp for sentimental reasons I think. I had a schematic for it but lost it in my latest move to another house.
Mailed with the original designer Tom Colangelo in 2003 about a conversion from 120V to 220V. He told me that he lost all his paperwork about these old MLAS models in 1989 due to tornado. Due to the age of 40 years of this amp and it's completely original it could be a candidate for some maintenance.
Maybe somebody has the service manual of schematics of the ML3. Any help is welcome of course.

This one has been converted to 220 AC already.

I’m converting 2-way speakers to 3-way. The 2-way speaker contains a 10” woofer and a 1” tweeter. I have a pair of 2” dome midranges: Dayton DC50FA-8 whom I’m going to use them for the midrange drive units. The specification is on attached. I decided to start designing crossover for the midrange units first. And I have some questions as follows:

1) Which data between frequency response and impedance response will you use for finding cut-off frequencies of the drivers?
2) If I’m going to create a 4th order acoustical slope, according to the spec sheet, can I set the cut-off frequency at the resonance frequency, 370Hz, where the amplitude response is naturally down 3dB around that frequency?
3) If it is possible, should I calculate the filter component values by 20 Ohms impedance based regarding the impedance curve?

I know the above questions are weird and I agree. I’ve read there’s a ‘trick’ suggesting the way for creating a steeper acoustical slope from the lower order crossovers i.e. 4th order acoustical slope from 2nd order electrical filter slope combining with 2nd order natural roll-off of the driver. And in this case, I find the -3dB of the driver is located around its resonant frequency. So this is the cause of the questions.

Looking for info on small 3way RadioShack car speakers. Found those in attic, making small box for them now.
Front looks like that pyle 3way wonder, you know which one i mean.
I could not find any info on RadioShack yet. They sound decent, no bass of course, but they will be used in garage from 150 Hz up.

Hi, I would like a moderator to cancel the signature under my post, I can not access to the control panel to do it myself.
Many Thanks.

Hello, my name is Robert, I live in Germany, I am interested in hifi devices, I also deal with the repair of faulty devices in the hobby variant.

To All HIFI Masters,

I would like to ask for your help here. I am helping my friend to fixing up a Myryad MXP2000 preamplifier... the power transformer to the preamplifier board is dead ("open" on primary side, already checked thermal fuse). Myryad has been sold off and I can't find any information about this transformer. I contacted the new owner, but it was sold off again 🙁 I only hope to obtain some info or a service manual!!!

I contacted Talema (the transformer manufacturer)... no success either. No one bother to respond to my emails 🙁

To you All, I would like to obtain the transformer specs so that I can source a replacement from Digikey or Mouser... If you have any information about this transformer, please help. Please see photos attached of this transformer.

Many thanks in advance

I’m looking for the above if anyone has 1 or 2 to sell .

Dear community,
I’m Michael and doing all kind of audio stuff like amplifiers, pre-amplifiers, DAC with or without tubes. It’s a pleasure to be here!

Hi all, My name is Adrian. I've always loved listening to music, but I never realized how much there was to learn about speakers, amplifiers, and other audio equipment. My first real insight into sound quality came when I acquired my first CYRUS system and Mission speakers. Since then, I've developed a keen appreciation for high-quality audio and have invested in more audio systems. I also have a passion for electronics; while I'm not an expert, I can handle some basic DIY projects. I'm excited to be a part of your community!

Hi everyone,
My name is Jesse, I'm 30 years old and 2 years ago I went back to college to get my bachelors degree in elektronics-ICT. The main reason I did this was because of my interest in analog elektronics and audio. Because there's only so much the courses can teach me, I decided to join this forum. I hope I can learn as much as I can, mainly about repairing vintage amplifiers and maybe some diy speaker builds here and there. At the moment I own 4 amplifiers, one quad 303 and technics 7300-k in good condition and one Technics SE-9021 and Yamaha P"something" power amp in dire need of repair.
Greetings!
J.

Hobbyist speaker builder and headphones tinkerer. Digital audio enthusiast. Daytime work AI, web, IoT, embedded, telco.
Sometimes looking for old schematics.

Has anyone the presentation of Frank at the ETF 2010?

Hello from France,
Happy to join DIY Audio.

I'm a cumputer science student who want to learn how to make my own connected speakers but I don't know sound engineering.

Which thread would you recommend to build my first connected speakers with low budget ?

Hello
i repair and build audio and radio gear.

I had some heat sinks laying around and a couple of stuffed Amp Camp boards (with Tungstenaudio mods) so I built a pair of monoblock amps. I don’t have any use for them since changing to Magnepans, so selling them along with a Front End Preamp.

The Pass Front end preamplifier has large wima capacitors, upgraded VRDN (voltage regulator denoiser power supply), and Antek transformer. Two balanced inputs and two single ended outputs. The pot is an RK27 Alps Blue 4 gang pot. I set the gain to 5db and it is near silent on a pair of 100db efficient Klipsch Super Heresy.

Two Nelson Pass Amp Camp upgraded Monoblock Amplifiers - custom built with solid Walnut faceplates and heat sinks from a local electronics store. The heat sinks have a few small scratches from being stored, but nothing major. The top and back is perforated sheet metal. I wired them exactly like the build guide (revision 1.8).

I will add more pictures of the internals tomorrow.

Asking $800 plus ship for both amps and the Front End Preamp.

Solved for now🙂

Up for sale are two unused RCF ND 850 2.0 compression drivers. Made in Italy. Extremely robust hardware. Each driver is 5.9 pounds. Made in Italy. $495 shipped to USA for the pair. We can talk shipping if you are outside US.

3-inch Diaphragm, 2-inch Exit Throat / Pure Titanium Compression Driver
220W continuous program power handling
Frequency range: 500Hz - 20kHz
3-slot optimized geometry phase plug
Titanium diaphragm
Copper inductance ring for extended response
Vented, damped, low distortion suspension system
Nedymium magnet assembly

Pictured below is the certificate of authenticity, as well as the boxes and drivers themselves.

Read more about these drivers here:

https://josephcrowe.com/blogs/news/rcf-nd850-2-0-compression-driver

https://usspeaker.com/rcf nd850.2.0-1.htm

https://www.rcf.it/de/products/product-detail/nd850-2.0

Like it said in the title does anybody have or know where I can find the schematic/service manual for a JB System PA 9600?

I built this for a friend who used it for a couple years and he changed his system. I took it back and made some slight adjustments in parts and wiring.

• AMB Sigma 11 power supply
• 4 inputs and 1 output
• Alps RK27 volume pot
• grayhill selector switch
• Aeon polypropylene caps (these were previously used when I put them in so they appear a bit beat up but they all measured correctly.
• 75% of the chassis has dampening to reduce ringing

-custom nameplate (put this here to cover some holes I had made for leds)
- back of chassis says “Dun Mei Audio” which is just the company that made the chassis.

Asking $450 shipped. Please only Conus.

Hi, I'm looking for a pair of 2N5566 dual JFETs, new or used. Prefer Siliconix or Motorola. Thanks.

Hi All

I am sure this has probably come up before on another thread so if it has and you can point me to it, I would appreciate it.
I am restoring and slowly recapping a Yamaha CA-710.
On the PCB at the time Yamaha used these pins and then twisted wire around them, I am sure worked fine at the time but it cannot be disconnected for service or repair.
I tried soldering and re-installing them but they never look as neat.

What suitable replacement have you guys used or the best practice for keeping the amplifier as original as possible.
Or is it just better to solder the wires directly to the PCB.

Any suggestions would be appreciated.

For Sale two thorens td150 mk1 and mk2 turntables. Mk2 has a alpherson opel arm with nagatoa mp10 cartridge. Mk1 is stock. I will have to take photos then you can understand what I got. Looking reasonable prive for both. Motors run whisper quite and at correct speed.

For sale in excellent condition. In uk west Midlands. And got some other hifi also

I'm looking to dip my toes into the world of track saws, but want to try it out a bit first.
Anyone have a track saw they're trying to part ways with? Could be tool-only – I can get an aftermarket track to save on shipping woes.
Shipping to NY..

I stumbled onto this thread that deals with the Amp Camp Amplifier on the Audio Science Review Forum. Although I've been interested in audio for many years, and even worked at an audio retailer while in school, I've managed to avoid such passionate disagreements on equipment.

I must have an awful ear since I think the ACA Mini sounds very good. Coupled with a pair of Parts Express C Note speakers and an inexpensive powered Dayton sub, the ACA Mini provides very satisfying sound -- especially when the price is considered! I've heard many systems that are considered "high end" which sound very nice, but when I consider the price, I'm content with what I have.

If you haven't read it, here's the thread. Sorry if this is old news, I'm still getting back into the hobby after a long absence.

https://www.audiosciencereview.com/...pass-aca-class-a-power-amplifier-review.9741/

For someone like me…

I am selling my Klipsch La scala for a very good price. First reason, I live way at the top of the Michigan peninsula and must convince someone it is worth the trip to come and get them. Second reason is that they are best suited to those with massive curiosity and not much money, that is why I am starting the sale on this forum and not with eB*y.

DIY rocks!

I bought them from someone who really didn’t know what they had. He thought they were loud party speakers, a thought backed up by the blown tweeter he forgot to mention. For me they were a chance and a reason to explore Flea Powered amps, specifically, DHT, single output tube amps. I am running these right now with a famous Gordon Rankin Bugle 45. (2W.)

These speakers changed my enjoyment of music for life - as did the whole of DIY audio. That is mostly because I was not born into money. I came into HiFi with a few thousand dollars and kept adding as much as I could to keep climbing the ladder to splendid sound. I got pretty far with some intelligent choices, buying and selling but one does see the sickness that is present in the rarified atmosphere of Super Stereos. Thats a whole different topic. Stereos should not cost money like a sports car costs money. These speakers are obtainable. They are not perfect but they have been on Stereophile “A” list for many years, all by themselves, not needing to be paired to special amplifiers or room conditions. After I got a hold of these speakers, I had a reason to learn to build. And build I did!


It’s a big lead in, I know. I’m selling them naked, no crossovers but in perfect operating condition with all original drivers.


There is one splendid addition in this speaker set: a Martinelli Trackhorn. It is rare that you’ll find one spliced into a La scala, it takes some woodworking skill. It takes a motivated listener to make it work well. You’ll find plenty of folks on the Klipsch forum who did a swap into their K-Horns and Belle as kits were available. I had to work it out myself. See Photos, I think it looks Good! I KNOW it sounds good. I’m willing to demo the sound to anyone coming out to hear them.


The crossovers (AA) can be purchased separately from Bob Crites, which are good, ‘better than the original I’m told or… we could negotiate for mine. My thought is to put mine up for sale to a wider audience as they can be shipped. Mine are ALK Universals using SUPER premium parts.


The main thing here is the speakers. You can get your foot in the door if you can get a decent sized SUV up here (Traverse City, MI - a Nice vacation spot 🙂 for a super low price. I mean, I paid $1000 for the freakin’ curved wood Martinelli Trackhorns, I am only asking $800 for everything (minus the crossovers).


*The original “K” series drivers are unmolested but have new diaphragms (via Bob Crites, A good guy 🙂. The cabinets are NOT banged up. The are flat and smooth with 5 thin coats of black hard enamel paint. They have carry handles in the upper section which is good for moving them around but no one has ever done a “gig” with these, just one move since I rebuilt them. They are Heavy.


The have stands and they work well… but they are not art statements. They DO help. They go with the cabinets if you want ‘em.



I have other things for sale but this AD is for the Klipsch La scala. Contact me for further information. That’s a matched pair of 1980, sequential serial number, Klipsch La scala in fine cosmetic and working order (minus crossovers) for $800. Come on up the the Great North Woods 🙂

soy de costa rica soy técnico en electrónica industrial con experiencia en el ámbito de la electrónica general desde antes de los 10 años actualmente arreglo desde amplificadores de audio hasta lavadoras cocinas microondas computadoras y muchas otras cosas más, que tengan un buen día y saludos a todos

SOLD! AD is now closed.
The NAD phono board has been sold and the PC-3 board has been scrapped.

--------------------------
I have two PCB boards (can't remember how I got these):

1 NAD 7020 phono board - complete looks NOS
1 Dynaco PC-3 board - missing caps, looks used (discoloration around tube sockets)

Free for postage from Montreal, Canada.

Just want to say hi from Vietnam after on and off for YEARS 🙂 in here

Late of 2020 if I remember correctly, first read was about CamillaDSP then REW, VituixCAD and many other audio related topics. Thanks for the programs, the knowledge you all share.

I'm here to research DIY projects.
I've been an audio enthusiast since the golden age of the 70s/80s.
At the time, I started studying about speakers and sketched out some interesting projects, given the scarcity of good products, in my opinion, with compatible prices, on the market.

Have a great week everyone.

Which I'll post in the correct place 🙂

Hello,

my name is Stefan and I am interested in vintage audio, especially from the 80s and 90s. Actually, I'm trying to repair my Canton Plus A active subwoofer.
And I am looking for Braun Atelier Audio (in gray) and Canton CA20.

Best regards

Stefan

Hi everybody,- glad to join the forum,- and just to say hello to everyone..

I'm mainly in DIY tube amplifiers, pre's, mono powerstages (latest is screen drive push-pull), phono-pre, but also in tuning and designing turntables, speakers and so on,- so basically everything all around analog HIFI...

Best regards from Germany / Neuss
Juergen

Hi, I'm here hoping to get some advice on how to repair some speakers I recently picked up. I've been collecting and repairing all sorts of electronics all my life. I love 90s and early 2000s stereo gear, but I like the older stuff too. I love collecting iPods, CD players (especially portable ones), and other old junk to refurbish and give away to my friends at school.

I recently had a friend bring a pair of Audio Pro Avantek 9 and Avantek 1 speakers new in box to me asking me to help him sell them.

He didn't give me much info on them except they are made in Sweden, good quality speakers, and he got them on close-out maybe 10 years ago. What I see online is good feedback but not a lot about price or what they compare to.

The only issue I have is that the 9's do not match. One is black and one is cherry while the 1's are a pair in black; I have been looking at options to either vinyl wrap them or get them painted but not sure if they are worth spending extra money to not make my money back.

1. Does anyone have info on what these retailed for new?
2. Are they worth getting vinyl wrapped or painted for around $350-$400 to match?

Hi everyone I will have a few questions about the opamps, first of all I have 2 fosi audi za3 monoblock connected amplifiers with a total of 4 MUSES03 installed on R channels on them,
there is douk sound t8 pro as a preamplifier I bought original 2 CD4052BM Chips from digikey with 10 NE5532 opamps included in this audio control and installed them, the sound is louder and the tone control is more stable,
i use OPA2134, OPA1612 for the changing opamps of the douk sets t8 pro it is quite quiet and hot with good quality,
my goal is to increase the sound quality even more for this I am looking for better quality, more lively affordable opamps from muses03 i would be very happy if you could help with this.

We all know matching the exit angle of the compression driver to the throat of the horn is the best way to go. However if there will be a compromise which one would be a better choice. Using an exit angle that is lower than the throats angle or one that is higher.

For example, take Yuichi Arai's 290 horn. It is designed to match the 10degree exit angle of the Tad 4001 (or JBL 2450, or even BMS 4592nd which is also has 10 degrees exit)

What if we wanted to use a Beyma cp850nd with its 7degrees exit angle. Would it be better than using a Radian 950 with its 20degrees exit? As the shape opens up rather than closing down it makes me think having a lower exit angle may work better however I have no experience on this.

What kind of a mismatch is more detrimental and at what frequency do these detrimental effects arise. If it is higher frequency ripples correlating to 2" throat size, then they would they be around 6700hz. What if we cut below that, surely it will still have an effect but would it be audible enough to consider a different cd?

SOLD
with or without the birch baffles and black walnut bases. With speaker wires. Plug and play!

Gently and responsibly used.

Does not include shipping. I can remove the bases so they'll ship efficiently.

Hello everyone,
I'm a big dub enthusiast and I've decided to finally build my own sound system !
Here to learn and have fun 🙂
Grettings from France

Hi everyone,
I just got a pair of this new MarkAudio fullrange drivers, the CHP-90 and would like to explore the options and have some advice for a nice build!
There are actually 2 rather interesting plans in the MA website, the Psamathe (some kind of TL) and a double bass reflex named Sycorax.
In another thread, the user nandappe posted a floorstanding TQWT that also seems interesting!
Another option I'm actually evaluating it's a so called "Hyper Bass-Reflex" (website of nandappe) that I would say a mix of ???Transmission Line and BLH??? Am I wrong?
I'm particularly interested on this one because I have now a pair of Dayton Audio RS100-4 in a small TLine adapted from this project named HADO and I have to say that they're really great! as desktop speakers! with really surprisingly great and pleasurable bass!!!
I'm actually testing the CHP-90 in a simple pensil and in a TL I've made, medium size box (45x25x25cm) but not really satisfied yet even because the material I'm using to prototype is styrofoam panels! of 3cm... so not at all acoustically perfect! 😉 but great for modeling!
Any suggestion is welcome! and specifically to nandappe I would like to ask if it is possible to have a plan of an Hyper Bass for the CHP-90 or if the [HB-03] HB-15F (in attachment and linked above) can be fine!

Hi all,
I have an interesting failure of an RCF amp module where its making a squealing sound that's varying in duration, here's a video of it: Login to view embedded media From a quick visual inspection the only thing I can see is the switch mode transformer looks slightly perished:

Just thought it would be worth an ask in case the hive mind has got any thoughts on a potential cause?

Cheers,

In some readings, I found that a center tapped transformercan be used as a splitter for a push pull output stage. That being said, of course it would have to be a high quality transformer.

I have not seen any designs utilizing this technique. Any comments on this application?

Roger

Hi
Anyone know where to find a datasheet of these mecrury wetted relays?
Clare 851 A24 B1A
Clare 951 A24 B1A
Brgds
Pix 🙂

I'd like to generate a pp tube amp design in the 30w to 60w range using materials on hand if possible.
Have some 5k ct output transformers coming this week. Have an assortment of amplifier tubes, but I wonder if it makes sense to use these new 3D21WB tubes I have, most of the other tubes on hand are used. Does anybody have any insight how to set up bias on this tube? I'm a newbie, and the tube is a 40 watt dissipation tube, I see load line charts with variations of G1 and G2 connections. Seems like I can get decent power, but also appears the voltage has to be pretty high, also the plate current, so I imagine the idle power would be atrocious. Thoughts from the experts?

TL;DR:
I have some big empty 6cu ft. enclosures.
I want to bring them to life in some capacity. Ideally to experience the "aliveness" of efficient drivers in big reflex enclosures.
I'm not after perfection. Here to have fun and learn something through experimentation and this community.
I'd like to keep it under $1k USD.

Long version:
I fell into some speaker cabinets that likely started their life as DIY Altec A7 enclosures and more recently were refurbished as a 515B / 802D combo by the person that gave them to me.
Here's a photo of the before and after. Note that I only have the cabinets. No drivers, horns, xo's etc.



I took some measurements and made a drawing to calculate net volume:


External dims are 36x24x15"
Gross internal volume 6.21 ft³ / net (without driver displacement) ~6 ft³

So now the question is, what can I do with these?

My only real requirements:
$1k USD budget
Limit woodworking to small mods – baffle changes, bracing, etc.
I want to build something high efficiency to pair with my Amp Camp Amp or Fisher 400, but I also have some 100W Class D amps available if I go the DSP route.
I'm fine with soldering but have no experience designing crossovers.

The more subjective stuff:
I'm "horn curious" – I love the way they look and I'm wondering if there's econowave projects that might be a good reference here (though I haven't seen any 6 ft³ builds yet..).
One thought is that enclosing the horn in the cabinet will eat up some volume and get me closer to some of the 5 ft³ e-wave projects (or the 4pi, etc.)
I'm open to DSP – and I'm thinking that could be a good way to learn about crossover design and room dynamics.
I'm assuming I will need to cut a new baffle – both for speakers size and for port tuning.
From a budget standpoint, these Lii Audio 15" coaxials are attractive – even includes a crossover.. but the T/S params are confusingly lost in translation.

What would you suggest?

Hello,

I have an old Onkyo DX-7333 which I just bought 2 weeks ago. At first it did not recognize discs at all, or was very picky when it did so I decided to change the whole laser assembly which resolved the issue, it plays fine everything.

Before that happened and I could listen to CDs and even after the laser assembly was changed every CD I listen to has a mild distortion in the analogue signal path - headphones and RCA out (SPDIF is perfectly fine).

I'm wondering if anyone has a schematic for this particular CD player, or service manual.

I'm a newbie but I would like to fix this issue. However I wouldn't want to start swapping out components one-by-one without understanding the insides at first. I couldn't find it on the Internet.

Any help is appreciated.

Best Regards,
Márton