Greetings

Just discovered this intriguing piece of audio history known as the Karlson acoustic transducer (thanks FETHead):

http://home.student.utwente.nl/e.j.j.ulfman/

Has anyone done any real empirical testing of the Karlson design? I did find a Norwegian commercial derivative of the K-Slot concept:

http://forsman.no/hjem.htm

More than a 'cult'? Opinions???

I have just learned that Manu Dibango died from covid-2019:

COVID-19: Famous Saxophonist Manu Dibango dies at the age of 86 | Africanews

Regards

Charles

I've posted an embarassing number of threads about Unity horns, going back fifteen years.

Something that's been a big challenge for me is the cost and crossover demands of three way loudspeakers. Basically it's a million times easier to make a two-way speaker than a three way speaker.

When going from a two way to a three way, the crossover tends to get about twice as expensive, and the complexity goes up like a hockey stick.

I had an idea, inspired by my last project that might make it possible to do a full range loudspeaker with controlled directivity using a two way.

I know that it's possible to do a two-way controlled directivity speaker if you put a full range speaker at the apex of a waveguide, like xrk971 did here, or if you use a large format compression driver, like weltersys did here.

But I have a thing for small tweeters and small compression drivers, so those solutions don't work for me, unfortunately.

Hi, complete newbie here to loudspeaker building. I'm trying to find a dipole tweeter to suit my Coral Beta 10's in open baffles (Slot loaded open baffles). I bought a pair of Aurum Cantus AST 25120 air motion transformers, which should suit the Coral's sensitivity nicely (95-98dB). The frequency response looked quite flat on the spec sheet (see attached pdf). However, I did a quick measurement on them, and found a huge dip above 10kHz (-10 - -20 dB). I measured them with Room EQ Wizard from 3k-22k without crossover, straight from both my 300B amps and a Denon transistor amp. Am I doing something wrong?

Many moons ago I had the schematics and instructions to mod and upgrade my Novacrons. I have since moved, and have found all the parts I ordered, but not the instructions. Does anyone have these instructions available as they are not online anymore. I remember one part was to put resistors from the output tubes (Cathode) ?... HELP!

Sad news. This afternoon a friend from Argentina called and told me that Juan Esteban Frind, aka Popilin, had died. The incident occurred on August 20, was 55 years old and had recovered from pneumonia. Only God can give us the answers to the mysteries of the death of young and healthy people. To this great member of whom I got a friendship that deepened with the passing of time, he who never boasted of some titles, had a deep capacity to solve physical and mathematical problems. He always said he was simply a TV repairman. Their discussions about the problems of magnetism in audio transformers were known. It has left us with no possibility of response, at least on my part, not having followed him lately in which it was known that he had serious economic problems due to the problems that accused his country. He lived in Villa Dolores, province of Córdoba and I hope, rest in peace my friend.

Need help with remaking connections around q4 it burned some trace and I don't have one to compair.

Would you try to bridge an fill in this damage to the edge of the ground plane or not worry about?

The damage is located on the back side of the board around the rectifiers.

David

Manfred huber

I apologise up front for any stupidity on my part - but where has Manffred Huber's website gone?

I have most of his articles stored on a computer that is now in storage and I wanted to look at his Shunt Regulater for a possible project

Mvh

Not sure if it's the right forum, but sounds like it is.

A very noob question but I did not see clear responses for that in a single summary place.

While looking at the pictures of builds, it appeared that some capacitors, resistors, etc. are soldered directly to switches, transformers and so on... likely to avoid artefacts, noises, etc.
Any good advices regarding these settings (what to use, where to use, for what)?

I'm looking for a pair of Vifa tweeters, and woofers

ERYN's TU-8800
"Tried some 6F6GT today and it sounds very good!"


Here is the Lundahl PCB board for TU-8800
Lundahl C-core LL2783C will be available next week - March 3, 2020

or have a source (preferable) of just the VFD display part. Or a player model utilizing it? TIA L

So I got two stereo Wollensak tape machines for cheap, and intend to use the power transformer for a 6AQ5 stereo amplifier. While they are being shipped, I downloaded the schematic (of a mono Wollensak, couldn't find t-1515 stereo schem) and saw this for the power supply:




I know a little about power supplies, but this I don't understand. Is Wollensak using line voltage to make filtered 250 VDC?? Is there a way to make this transformer (I assume the stereo one is same) work in a 6AQ5 amp, or ought I just look for a more conventional PT? Thanks!

I have been building speaker projects for years but now I want to build my own headphones from scratch. However, I am not sure if the same principles would apply. I really want to make something unique completely from scratch and not use existing headphone drivers (this is the same as buying already known headphones).

What I'd like to do is use a 3" full range woofer from Mark audio and position the driver inside cups so that it is roughly 1" from the year. Would this work or sound good?

Finally, how do I make sure that I get a flat frequency response from the highest to the lowest frequencies?

Any help would be much appreciated. Thanks guys!

I've noticed theses speakers and most of the people who heard them rave about them.
Also, this review is quite interesting http://kiiaudio.com/en/component/ph...?download=2:audio-review-test-09-2015-english

Has there been such tryouts in the DIY section?

I bought this B&K Reference 125.7 amp with 6 out of 7 channels working.
Have been looking for this or the 200.7 for 3-4 years and knew I could only afford one if it had a bad channel or two. They are still bringing decent money some 20-years later.

The blown channel had actually blown off the traces where the lateral mosfet had shorted at the gate resistor. So I tested all the remaining 6 channels and they were working fine. And went about replacing all 4 output FETs with Exicons, matched best I could with the 8 I had on hand (all of them were quite close).

Powered up and was not getting drive to the outputs, so I ordered new drivers BJTs (2n3440 and 2n5416) from Mouser. Even though they tested good out of circuit. Installed the new parts and that channel was working.

Bad news - while testing why the outputs were not getting drive, I shorted a resistor and blew a trace off a working channel, as well as the negative side rail fuse for that same channel.

Repaired the traces, resistor and tested all pre-drivers, replacing any that tested as bad (I think there was 3 on one channel and 2 on another).

Now it was working 100%:
All Channels working and set bias and played for over a week off and on - probably 20-30 hours in total at normal listening levels. I also dummy load tested each channel at 70% power on my O-Scope and all channels looked to be working. Sine was smooth, clipped as expected and got about 185W at 8r and 235W at 4r on all 7 channels.

More Bad news - and a weird happening:
I put the amp in my HT rack, with brand new XLR cables and watched 2-3 movies and my son played xBox for about a week. After about a week, I finished watching a movie with my son and I wanted to feel how hot the amp was getting and make sure ventilation was adequate.
I touched the top of the case and heard a "crackle" (a small 1-2 second buzz, then pop) through one channel (Right surround). The case was warm but not hot at all, probably 35-40C, which is slightly more than is ran on my test bench for a week.

I turned it off and when I turned it back on 2-3 minutes later to see if the "crackle" was still there - DC out of that same right-surround channel and before I could turn it off, it had a loud BUZZZZZ and blew the woofer (5-1/4") in that surround speaker. Now that channel is dead - no DC being output?

I pulled the amp, tested all the other channels (they all work fine) and this channel was a working channel when I bought the amp, but was one of the effected channels by my "mis-hap" with the DMM probe.

Long way around to the questions:
- I have tested the (2SK1058/2SJ162 - 1 pair each) outputs and they test fine, both with DMM out of circuit and 2 different eBay testers
- I have tested the drivers (2n3440/2n5416) and the only strange thing compared to a new part is the old parts Ic=6mA, where new part tests Ic= 1mA, this on the eBay testers, not an actual test jig though.
- I have tested all the pre-drivers and they all tested within spec. I also verified all resistors and diodes are in spec. and working, pulled the caps and verified with a tester within spec. All rail voltages are within spec too.
- Is this possible that the drivers going bad, could cause DC on the output and fry my woofer? Then blow the channel without harming the outputs or blowing a fuse?

Any assistance would be appreciated, as I'm confused why on the drivers are testing bad and would do anything but not turn-on the outputs?
I have new parts coming this weekend, but I can't find an exact schematic (there are similar versions with different FETs, but not exact), but doesn't appear to be very complex design either. The only strange part is it has +/-65V (red/black) going to the 4 channel board, and also has +/-65V (Red/Orange/Black) along with Ground (Green). Not sure why it needs two wires carrying the same rail voltage, but I think it is a mute circuit possibly, testing if there is full rail voltage (guessing though).

Hi guys,

I´m new in speaker building and I hope you can help me with a problem.

I´m currently working on a couple of simple full-range Bluetooth speakers I want to build for a cabin we have in here in Mexico.

I have been doing some tests with different types of amplifiers, speakers and power sources, but it doesn't matter what combination I use all of them are really loud and start to distort at half the volume.

The biggest issue is that we are renting the cabin for the weekends and holidays and everybody that rents the house will have access to the speakers so I know some of them will play music at full volume and I don´t think the speakers will last.

I´ve been taking some measurements of the voltage of the output of the amplifiers to calculate the RMS watts each amp is giving and none of them go higher than 15 watts and all of the speakers I have are at least 30 watts RMS.

Here is a list of all the components I´ve been testing.

Speakers:
- Dayton Audio PC83-8 3" Full-Range Poly Cone Driver
Dayton Audio PC83-8 3" Full-Range Poly Cone Driver

-Dayton Audio PC83-4 3" Full-Range Poly Cone Driver
Dayton Audio PC83-4 3" Full-Range Poly Cone Driver

-Dayton Audio TCP115-4 4" Treated Paper Cone Midbass Woofer 4 Ohm
Dayton Audio TCP115-4 4" Treated Paper Cone Midbass Woofer 4 Ohm

-FaitalPRO 4FE32 4" Neodymium Professional Full-Range Woofer 8 Ohm
FaitalPRO 4FE32 4" Neodymium Professional Full-Range Woofer 8 Ohm

Amplifiers
- TPA3110D2 2.1 Channel Bluetooth 4.1 Digital Amplifier Board 2 x 15W + 30W with Volume Controls
TPA3110D2 2.1 Channel Bluetooth 4.1 Digital Amplifier Board 2 x 15W + 30W with Volume Controls

- KEYREN Power Amplifier Board, Digital 2.1 Channel Amplifier Board Bluetooth USB TF Input 50W+50W Stereo 100W
https://www.amazon.com/-/es/KEYREN-...etooth+amplifier+module&qid=1585454385&sr=8-9

-Cuawan ZK-502L Mini Dual Channel Stereo Amplificador 5.0 Bluetooth Amplifier Board Wireless Digital Power 2 X 50W
https://www.amazon.com/-/es/ZK-502L...tooth+amplifier+module&qid=1585454817&sr=8-12

- AOSHIKE DC12V-24V 2.1 Channel TPA3116 Subwoofer Amplifier Board High Power Bluetooth Audio Amplifier Board 50W+50W+100W (Bluetooth Amp)
https://www.amazon.com/-/es/DC12-24...&sr=1-52-dd5817a1-1ba7-46c2-8996-f96e7b0f409c

Power source

- 12V 1Amp

-15V 4Amp

-18V 3Amp

Is there an easy way I can limit the volume or gain on the amplifiers?

Hi,

I have been fiddeling around with my 8 + tweeter for a really long time, and I think they are awesome.
For music duty they are more than enough, but now I am putting them in a bigger room where they have to double duty for music and movie/gaming for the rest of the family as well.

I don't play really loud and I don't care if I dont get that last octave. But I want punchy, articulate bass and a speaker that can handle full range material. And around 91-92db/ 2,8V after baffle step.

I'm planning to cross over at around 200hz.
I have 3 options I have been thinking about.
Eminence Legend BP122 in closed cabinet, Eminence Kilomax Pro 18A in open baffle (Troels Gravesen style ob15) or the bass section of Bill Fitzmaurice David (I used to have 2 Lab12 loaded THTLP's which sounded awesome).

Cost wise these 3 options wouldn't be too far off each other when the cabinets are taken into account. (The 18 inch will be a bit more expensive)

So any opinions or adwise?

Despite the technical nature of the discipline, the appreciation of sound is ultimately a subjective issue.

I don't "make" things. I cannibalise broken or damaged speakers.

A desktop system brings different challenges. Your feet are generally 18" away from the sub and each satellite is only a couple of feet away from your ears. THe underside of the desk acts a low ceiling causing the sub to sound boomy.

I bought a cheap Bush sub from Ebay for £5.00 ($6.00). BUSH CHT100DVD HOME Theater System Subwoofer (NN) - PS14.99 | PicClick UK Beneath the macho (8") cover on the side-loaded driver is a wimp of a 5" unit. I have replaced this a 6.5" bass driver salvaged from a TDL studio 10 Studio10.

For the satellites I purchased a pair Ariston MX-30 (£10). Superb Bookshelf Speakers For Sale in Sprotbrough, Sth Yorks | Preloved

I am super-impressed by the results. It is probably the best sounding desktop system I have owned. The original unit was more than worth it just the port flare and the 100w plate amplifier.

Dear All,

Can you help me identify this potentiometer ? It is an APLS PCB 10mm, with a value of 20kOhm. What I do not understand is why it has 5 pins.

It comes from a Zoom RhythmTrak RT-223.

Regards,

Davide

I came across a set of old Group Buy boards. Anybody recall the build threads for these boards?

• I think the green boards are Chad or hifizen Aleph-X amps Dec 2002,
• One set of red boards are X-BOSOZ layout by KH 2005
• Other set of red boards are Aleph-X amp layout by KH Dec 2005

If memory serves the Red Aleph-X boards were good, but needed one trace cut and rerouted.

I'd like to build an A-X, but probably won't build both. Appreciate any help or guidance for build threads or which is better than the other.

Thanks!

Don't know if this is in the right section but here it goes:

As I am a lot at home now because of the Covid-19 it's time to do some stuff that is on the "to do" list.
One of those things was to refurbish my marantz 2265B receiver a little bit.
It has the usual intermittent contact problems etc.... normal for something that is 40+ years old. Hasn't been touched as far as I can see (yes it is older then me, got it for free a few years ago).

So I cleaned every switch/pot and replaced al the electrolytic capacitors in the power supply/preamp/phono pre/output amp.
I left the tuner electrolytics in.
I checked DC offset of the output amps and checked the bias. I also cleaned the DC offset and bias trim pots.


Then I used a test transmitter to adjust the RF section. The discriminator Transformer coil was a little bit of, as do some of the RF stages.
Reception is a lot better now

I also replaced al the fuse lamps as they where all gone.


So after this process al of the switches and potmeters work again like they should. Sound is a lot better. Look a lot better also.

There is one thing that remains.
When the receiver is turned on and still cold one channel is down in volume/distorts. Putting some more volume makes it become good again.
I checked the RCA connectors as they have a pre/main output so you can put an equalizer or something different in between the pre and output amplifier.

So after some reading it looks like some of these japanese transistors can go "bad" and develop some weird intermittend problems.
So I was thinking of replacing some of the small transistors on the preamp and at the input of the main amp.

The transistors are:


2SA798 (double PNP transistor)
2SC1345 (NPN)
2SA722 (PNP)

I could maybe do the phono stage as wel:
2SA872 (PNP)
2SC1885 (NPN)
2SA912(PNP)

So most of these are (ofcourse) obsolete.
Any ideas about replacements?
The double PNP is a difficult one.
For the phono input having lower noise is nice but the noise is not a real issue.

Hi all,

i'm actually looking for a schematic for an tube preamp or buffer with an ECC82 per channel which will run at roughly 70V (48V rectified and filtered).

I really want to get behind the "witchcraft" of the circuit. So i need some explanations which value is calculated in which way.

Before i get ripped apart for using ether an ECC82 or only 70V:
I want to drive a ss se amplifier with this (that lovely 2sk1058 mosfet amp from Mark Houston) and i got 2 tubes and two transformers already. Even the case is allready there. That's why i'm asking for a schematic which will use only 70V as B+ (if an voltage doubler isn't preferrable).

It must not surpass the High End region. It will be there to glow and to control the volume.

So if someone can give me a hand with this 🙂

Hope you get what i'm talking about in my way of english XD

So I have this magnificently destroyed amp to deal with as you can see in the photos. I need help finding the rectifiers.

I did a search on the part number on the package and google turned up nothing.

Transformer became so hott some of the windings came out of the board. I have alot of work ahead of me.

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This from a recent article:

“Amazon Music HD offers customers more than 50 million lossless HD songs, with a bit depth of 16 bits and a sample rate of 44.1kHz (CD quality). In addition, customers can stream millions more songs in Ultra HD (better than CD quality), with a bit depth of 24 bits and a sample rate up to 192 kHz.”

Anyone have any idea if the Ultra HD format is just resampled from CD format?

I am currently building a small system for the office and was just pricing a new DAC either buy or build. The availability of a wide selection of 24bit/192Khz material will definitely impact my selection process …maybe not buy a Schiit Modi Multibit??

--- ALL 3x MODULES ARE SOLD ---

Hello Everyone
This is my first question m asking here.M new here, So sorry if i forget to clk something or mention something or whtever.

I have made a 2.1 audio system using 2- 5inch woofers as mid way speakers and 6inch woofer as woofer. Everything is going good but the woofer enclosure i made isnt producing tht much base, it just producing "punch" type bass not deep bass. The bass is just coming from the woofer not from the vent and covering the vent didnt effect tht much.(See the enclosure design (i) in attachments.

I doesnt like punch bass, i like the "echo" type of bass (or deep base i dont sure wht to call tht type of bass).So i searched a lot and i found that to create a deep base i have to add larger path difference between sound from front side and back side, so i m thinking of a different enclosure (see the ii design).
I didnt create the enclosure yet coz m not sure if it work or not (thts my problem).M thinking to use pvc pipes in "curly fashion" to increase the path difference. So i want to know will this work or have to add something more?? Do i have to fill the downward space with something??Wht should i do now??
Btw in design ii i showed tht the path is like "S" (coz i showed in 2D) but actually its is more likely to "spring shape"(sqaure spring or whtever).

And my woofer box vibrates too much thts why sound get distorted too much, wht should i do to stop it or decrease it, currently m using heavy weight to stop its vibrations.

Again sorry if i forgot something,Now m waiting for the answers 😀🙂😀🙂

I was curious if there was any music specifically for headphones.

As kids my brother and I played around with music for headphones by making
recordings using two microphones back to back and about 6 inches apart then
playing music through the stereo speakers that were 10 feet or so apart.

Is would seem that it would be quite interesting to place the
microphones in the prime listening spot and have an orchestra play.

Is anyone doing such recordings?

Thank you

Can anyone who has a Krell KAV 300CD please measure the secondary outputs of the transformer.
I would be much appreciated
Thank you Paul

I have a pair of 2214H woofers l100t from JBL speakers I aquired. They are in good shape and work. Have heads they were solid woofers. Would rather them be appreciated than not used. I've looked online a little at the few I found selling to see what they are being sold for. I will consider all offers as I'd like to sell quickly and have someone put them to good use. My direct email is mattcorronjr1989@gmail.com thanks

Hi.

I have a pair of 751 and a pair of 751 Freedoms. I have recapped my Cyrus One with great success and now wonder if I should upgrade the components on the 751 crossovers, rewire them inside, and mess about with the filling. Does anybody have a circuit diagram for the crossover(s) and any experience of modifying them.

Many Thanks.

Hi Everyone!

This is my first posting as a new member.

I bought a Forte 1A a few months ago. The left channel always causes the speaker to make a "pop" noise when the amp powers up. Also, after preamp and amp are powered up there is a low frequency hum coming from the left speaker. Not sure if I can hear the buzz from the right speaker.

The left speaker also makes a "whoosh" sound when powering off the amp.

Has anyone else experienced this? Should I be concerned about maintenance?

I am a bit new to this hobby and do not know much about this amp.

My setup:

Speakers: Ologe 5, LS 50 wired, Magnepan LRS
Amp: Forte Audio 1A
Preamp: Bryston BP 26



Thanks!

Hi, I noticed a difference between left and right channels so I decided to open up the PLD1100 and take some measurements. I found that left channel is sitting at 90 mv and the right is sitting at 240 mv. So my question is what is the proper biasing voltage? Any help would be appreciated. Yes I asked Parasound and was told 2 volts, I don’t think that is correct.

I have a home-brew VSE RTP3 (schematic here), which I built over ten years ago. I have been getting some noise from one channel, so I thought I'd test the obvious circuit points. The anodes of the line input cathode stage were a bit off the design 150V, so after checking that the current sinks on the cathodes were working correctly, I measured the filament voltages on the five EH 6922s in the line stage after ten minutes or so of power-up. These turned out to be all over the shop, varying between 4.5V and 6.5V. Looking at 6922 data sheets, I see that the filament voltage is 6.3V, plus or minus either 0.3 or 0.6V, depending on the brand, at a nominal 300mA, so at least some of them are emitting well under spec in my circuit.

Now the filaments are supplied, as Allen Wright preferred, by current sources (an LM317 with 4.1R between adjust and output pins). I checked that all the resistors have their nominal value, and the LM317 reference voltages were within a percent or so of 1.25V. So the filaments are all passing close to 300mA, but the deviation from the nominal voltage was surprising.

Has anyone else used current supplies for the filaments of small-signal valves? Have you found significant variation between brands, or any long-term changes in the filament resistance? I'm reluctant to tune the resistances on the LM317s for each 6922, since this makes valve replacement awkward. I'm tempted to substitute the current sources with voltage regulators, but constant-current uses only half the number of parts as constant-voltage.

Any thoughts?

Thanks,

Alex

Hello all,

Posting here in case anyone has experience with these particular components - I am out of ideas.

I have purchased a TSA3117B amp/bluetooth board from TinySine (tinyosshop.com), of which the bluetooth board is programmable (AudioB Plus Bluetooth APTX module - containing the CSR64215 chip).

I have purchased the CSR USB SPI Programmer and the IDC-2050 cable to do so.

However I am having massive issues, that is, I can't seem to connect it to the software. The chip cannot be read no matter what I try.

I am using the softwares supplied on the tinyos website which are:

- Bluesuite 2.5.0 (the USB-SPI shows up here but does not connect to chip)
- CSRA64XX and CSRA63XX Tools (the USB-SPI connection does not show up here at all)

I first tried on my Windows 10 laptop with no luck, then watching darieee bluetooth related videos on Youtube (and hearing how temperamental the software is on Windows 10) tried a Windows 7 32 bit install on an old laptop of mine. No success.

I have then gone and downloaded some newer versions of bluesuite and had a go but no luck again.
I have tried to re-load the firmware file from the TinyOSshop site using BlueModify but it can't read the chip either.

The chip goes into red/blue flashing mode when connected to the USB SPI (as it is supposed to) but that's all it does.

I have contacted TinySine via email but am yet to hear back. I am tearing my hair out at this point - doubly so as I just completed the build of a mono bluetooth speaker and I can't use it until I reprogram the chip to output to mono.

I know there are some very smart folks around here who program these things using their own cables / programmers - so if anyone on here is able to assist in any way I would very appreciative.

Thanks in advance.

Patrick

I was able to acquire a Crestron 16x60 amp, unfortunately one speaker terminal on the back was snapped off. I was able to obtain an OEM replacement and it looks like it would be a pretty simple replacement.

Can anybody provide any guidance? Would greatly appreciate it.

Thanks,

is there anyway to back up SACD music into a Windows PC ?

It'd be awesome if I could somehow store the music files in its native uncompressed format as high as DSD512 or even DSD128.

My car was stolen and I lost over a thousand dollars in SACD's.
I'm going to rebuild my collection of SADC's but would really like to be smarter this time and store all that music into my 12 Tarabyte external hard drive.

Do you know how to do that?

kind thanks,

Need help for a beginner - grounding scheme (icepower 500asp, 500a)

hey all


beginner/hobbyist here, needed some assistance/guidance from the pros


started getting a really nasty noise that coincided with hdd activity through the speakers



my signal chain: cpu --> udac8 (usb) --> amplifiers


after much debugging, i completely narrowed it down to the usb cable carrying this noise


i modified the cable, it now has no gnd path, still the noise


i believe i solved this when i opened the udac8 up and re-sat all connections, however prior to that, i started digging around my amp wiring and it lead me to here


the first realization i made was that my RCA has no (V-)! (i think?). i originally had the RCA shield tab connected to both AGND and (V-) on the amp, however cutting the V- path seemed to clean up things quite a bit. progress!


however here is the latest. when i have (1) rca connected to the amp from a powered down udac8 (literally nothing connected), quite as a mouse, however when i connect a second rca from udac8 to the amp, i get an increased hum/noise floor


if you guys could validate my wiring diagram, that would be most appreciated!!!

Hi,

I've been looking at this F5 article circuit on and off for a couple months.
I have a couple basic questions.

Is the 16 ohm resistor rated at 16W?

16v through 16 ohms is 1 amp? 1A x 16v=16w?

Thanks,

Vince

Hi: I'm in the process of upgrading the opamps in a Rane ME60 1/3 octave stereo equalizer. There are like quan.70 - 741 style opamps in this thing. (OP11 mainly). I'm upgrading to OPA1654 for the bandpass filters and OPA1656 for the rest. I have the early version (1991), but my schematic is from the wayback machine and it's pretty low resolution.
Does anyone have a high resolution copy of Drawing 521-147? Especially the layout drawing. The schem I have is OK, but the layout is unreadable.
Thanks in advance.

I'm search of a fine set of speakers for my first vintage set.
Hooking up on a Sony TA-F4A amplifier.

My first choices were B&W DM4 or KEF SP 104 the looks are very vintage and must sound great but don't come cheap.

When i scrolled down the adverts every time I came across a pair of Technics SB-5 but found the looks to modern.... Imagine in that day it's was a novelty homecomb speakers.

But the price they asked 40 Euro.....!!! I had to look. Went there and it was an older couple. They are the first owner and always been kind on the SB-5.

Measured ohm 7.6 ohm... All speakers came sound from... Yes great...

Took out the crossover board. But wow that's a solid piece of hardware.

Now the main question. What brand of capacitors should I choose? There are so many. Nichicon i know is good... But which line?

Can someone point me in the right direction?

Thanks.

Hi,
I really love that I have android at car.
I have Joying android sys.
It is A chinise brand with good build quality, everything is really smooth.

But I facing with A situation that I want to have A better quality in music.
Looking for A nice-fair entry level 7"-8" +- multimedia Double-Din system that support androind mirror link (mirroring the phone on the system) ... about 250$.

I dont have any special requirements except of fair quality in terms of suound and mirror link.

Amazon or eBay prefered.

Amp: Hertz HDP4

Thank you!

What to do with 100m of fibre optic cable I found?

Dear,

I'm lurking this section of the forum since a longtime and learned a lot. I'm thinking of a first self build phono pre, and after considering many shematics and kits, i found this scheme from Wes Kinsler. It's simple (what i like) and i think it looks good. But as i'm stil a bit a noob on tubes, i would like confirmation that it's worth building it as first tube project. I can't spice it myself as i don't understand the software (yet). So if someone would be so kind to do it for me, i would be very thankfull...


Tube Phono Pre-amp

I can tell i like the sound of 12AX7 based preamps (so if you don't like it, it does not matter for me). I did hear a few and like them more than 6922/6DJ8 based preamps i heared. It will be coupled to a solid state amp first, but the next step after this project will be to build a SE amp as I like those a lot.

The power supply i can design myself, wich will be full DC (also heaters) with heavy filtering and diode rectifiers. I also can get rather cheap but good power toroidials from a friend who winds them as job and hobby.

I'm not an electrician, but i do have a past as soundengineer with a decent basic knowledge of electronics who was not afraid to fix equipment himself, and i do have repaired a few tube compressers, preamps and bass and guitar amps. So working on high voltage stuff is not something new for me.

Good Evening everyone. I hope everyone is doing well? Well I have a few questions? I am looking at getting a pair of cables that can go from my computer to my Nad integrated amp. It is a older one but, is in really good shape and sounds very nice. I am only needed a cable for 6 feet long. So here are a few questions?


1. Does thickness and gauge of the wire play a factor?


2. Does unbalanced and balance matter to the sound of the cable?


3. Does gold plated or brass or all copper matter in sound?


4. Does cost matter in sound?


The reason I ask is I am placing a order with parts express on Tuesday and I can get this cable for very cheap? Audtek 3.5mm to RCA Stereo Audio Cable 6 ft..


I know there are other cables out there for lots of money but, is it worth it? Thanks for your help. Cheers Jeff

This will be my first attempt at using waveguided tweeter.
I already have a pair of spare Seas W22NY001 woofers, a set of Monacor WG-300 waveguides and a pair of Seas 27TDFC tweeters on the shelf.
I also have a suitable cabinet where the woofer will drop right in. Only need would be to re-tune the port.
The cabinet also have a cutout where the 27TBCD-DXT tweeter would drop right in.

My dilemma is; do I order a set of DXT tweeters or spend time on woodworking and use my WG300/TDFC combo. Which would give me the best results in terms of fidelity and XO design?
Any opinions and ideas for my project is appreciated. Will the WG300 allow for a lower XO frequency and/or lower order XO?
I have not seen any measurement for the WG300/27TDFC combo, but the data for found over at Zaph|Audio for the same tweeter in a similar looking WG looks promising.

Attached are the datasheets for Seas Woofer and the DXT tweeter.

hi ...

need help here ... i am interested of ported subwoofer boxes all the time (in fact have build 2 of them) due to their good efficiency (higher output at lower frequencies)...

but so far i am pleased with the output level they produced (very power bass) ... but there is something is missing ... that is good transient response(tight bass for eurodance, techno).

i wonder if for a subwoofer box a larger box then the suggested volume or smaller will give better transient response. Or i can use equalizer to improve the transient response of a ported subwoofer.

In fact, i do have a pair of sealed sattelite speakers which produce nice tight bass although the bass is not heavy.

pls help ... opinions and suggestions are very much welcomed

I am working on completing and testing 6 total amp camp boards and decided not to move forward with building full amplifiers. This is a great opportunity to build your own amp camps and save money since the kits are out of stock in the store. What I have for sale:

Package #1 ($225 Shipped)
- 4 stuffed boards that all match
- 2 Large Heatsinks 8in H, 9in W, and 3in D
- 2 XLR inputs
- 2 Power Buttons
- 2 Pairs of RCA inputs
- 2 On-On switches for bridging
- 8 IRFP240 Mosfets
- M3 Screws, washers, and standoffs
- Micca insulator pads

Package #2 ($100 Shipped)
- 2 stuffed boards that match
- 4 IRFP240
- 1 Large Heatsink 8in H, 9in W, and 3in D
- M3 Screws, washers, and standoffs
- Micca insulator pads

I will drill/tap the heat sinks and bias and test each board before shipping. I have successfully built multiple amps with these heat sinks by mounting two boards onto each on and it dissipates heat VERY well. I used a mix of Vishay resistors and some other spare resistors from other kit builds.

The heat sinks i bought locally from a store near me and they have pre-drilled holes, which is why I am able to sell the packages so cheap.

Shipping to the CONUS ONLY.

i fail to play this: Progress 24 — Another Sound System Experience | Last.fm


does it work at your side? is there a way to download it from last.fm (never used this service before..) or to find it somewhere else where i could listen to it? I have heard it on a radio and fail to find the band or group using the mighty Google!

Hello !

I would like to build a subwoofer, and need some advices ! I'd like to make something like the Adam t10s, the goal is to hear sounds at 28hz.
What interior design is the best ?
There are some small and cheap class D amplifier in aliexpress, what do you think about that ? It is ok for me if the amplifier is external.
It will be used in home studio, with Adam a7 satellites, at low and medium level. No need to be extra loud, I prefer sound quality than power.

For an other diy projet, I use a little cheap (16€) class D amp for a guitar cab I made, and I have to say that it works pretty well.

Thanks a lot in advance for your help !

I x pair of Brand New Pass DIY Aleph J PCBs from the DIY store.

I didn't read the advert properly and bought 2 x pairs so have 1 x pair spare.

This is enough to make 1 x stereo amplifier.

These are in the UK, Duty Paid.

£35.00 incl carriage to mainland UK.

Hey All,

Thanks in advance for your help here. I recently acquired a NAD 7020 amp and found that it had a dead channel. When i dug into it and probed around with my scope, i found that i had signs of audio all the way until the emitter of Q608. The base showed audio, the emitter had nothing.

I pulled the board out of the amp and saw that r644 was burnt up.

I replaced r644, powered the amp back up and quickly measured the voltage drop across it, and it's around 8 volts, putting the dissipation at a watt. I shut the amp off before it burnt out the next resistor.

I checked the values of the other resistors in this circuit and also compared to the working channel, and everything seems to check out. i checked the transistors with a multimeter too.

Clearly there's something causing the excessive draw on this side, but i'm not sure as to the best way to approach troubleshooting this as i'm a little new to the trade. I'd appreciate any guidance as to the best way to approach this problem.

attached is a segment of the schematic i'm working off of:

thanks again,

$70 + shipping for this new head cab, new reverb tank, and new hardware. I have tolex and speaker cloth too I will throw in for another $10.
Thanks
Jim
Landrum, SC.

In building a 4 cubic foot HT sub using the Ultimax 18, which would be better to reduce cabinet resonances, bracing similar to the kits provided by PE, or mass loading the walls of the cabinet with an additional layer of 3/4" stone like granite or marble?

Ignore the weight differential, as nobody moves their sub often. Yes, both could be done, but would there be any value to bracing & mass loading?

Looking for the value of the thermestor for this amplifier. With the broken one being unreable. The two points of the contacts measures 15k without any in circuit. Hopefully someone has one or knows this is value

Hello,
I recently had a problem with an alpine pdx 1.1000 that bumped very strongly at startup and broken my subwoofer. Seems to have dc offset on startup .
Locking to another discussion when an user had a similar problem with another pdx m6 and seems it fixed replacing chip irs20956s
I opening my amp that is little bit different and I drivers ir2010 .
What I noticed factory chip weldings seems not so good . I will try to fix one by one before replace .

I'm hoping some might be interested in evaluating this derivative design for a computer desk amp I drew up.

Asking for any input at all about this schematic I drew up for a computer desk amp, errors, improvements or if its all just junk! Firstly I have to say that the amplifier portion of this diagram is not my design, it was derived from two interesting schematics I found at the Electra-Print site. But all the switching, power supply, bells and whistles, case, etc. I am attempting to design myself.

Electra Print credits:

Input idea:

Electra-Print.com PVA Pre-Amplifier w/70 Hz Cut & Bass Volume Control

Amplifier:

https://www.electra-print.com/docs/6bx7se0001.pdf

The purpose of this project is a design that will be used to drive a set of 5 to 6 inch near-field speakers that typically roll off fast below 70Hz and a small powered sub-woofer under the desk. I spend a lot of time at my desk organizing my 300,000 track library of FLAC files, researching a lifetime jazz-history hobby, and doing DJ work for the local ballroom dance community here. So I thought what better project for me than a computer desk amp and the satisfaction of having done some of the design myself over a kit. My wife often wants to connect her phone, we have an Alexa and a Tidal account and occasionally a need to plug in a headphone out of something else portable. Also it has speaker and headphone listening modes. Currently I use a Teac class D amp at my desk with similar source input capabilities.

Some circuit explanations:

C1 and R3 form a 72Hz cutoff high-pass filter when engaged by S6, or the desktop speakers can be run full-range. The send to the sub-woofer is full range as that has its own low-pass filter. The voltage doubler in the 6.3 volt filament winding is for a 12V case boxer fan. The amp will be mounted in a "two story" case to reduce its horizontal footprint, a bottom chassis and a top chassis. The power supply chassis at the bottom floor meaning the rectifier tube is inside the wooden box so I want to cross ventilate the box with the fan and some perforated metal to still see the tube inside. All other tubes will be on the top floor chassis exposed. I indicated the ground bus for each "floor" of the case (see jumper). I dont know my voltages yet, but I have several Antek torroids to choose from in stash, I was going to parallel the HV windings to reduce the transformer impedance and not waste a winding. I used a hybrid bridge rectifier in the hopes of alleviating the turn on surge that way.

In addition to any criticism I have two main questions remaining if anyone can help...

1) What final voltage for B+ should I arrive at?

2) Would a 1.6K OPT work? Electra Print specifies a 2K OPT but I have in my stash a pair of OneElectron UBT1's just collecting dust waiting for a project. Those are rated 1.6K at 160ma. Do you think I can get away with using the 1.6K UBT1 transformer without any changes?

3) I dont know Spice yet, so I expect to be doing this by trial and error.

This is a poll regarding a fundamental question about the stereo system architecture. And it's a hard one, only Yes or No is a valid answer. Here it goes:

- Do you believe that the stereo system architecture (2..n mic, 2 channels, 2 speakers) have the properties to faithfully reproduce a live audio event like a guitar, piano or a symphony orchestra so that when your blind fold was removed you where surprised of what you saw.

Yes, I believe the basic stereo system architecture has the properties to be able to completely fool the listener to think he/she has heard a live event.

No, I don't believe the stereo system architecture has the properties to be able to completely fool the listener to think he/she has heard a live event.

NB: The question is not about if there exists or have existed a system that is able to do this (if you belive this, please vote Yes), the question is about if it would at all be possible given the architecture.

Remember: It's your opinion, not what other may think, that is polled for.

Is stereo fit to pass the Turing test?

//

FOR SALE

16 x 2SJ74GR P Fets.

I bought 21 of them from a genuine supplier for matching purposes and have 16 remaining.

Obviously I have taken 2 pairs from the original 21, 1 I blew up during testing.

The remaining 16 reveal 3 pairs that match to within 0.4% Vgs (in pairs), 1 pair matches to within 1%, 1 at 1.4% and 1 at 2.5%. There are 2 rogue devices depending on how tight a match you are looking for.

£32.00 for the lot plus P&P.

Hi all. Long time lurker, first time poster.

I've had this amp now for quite a while. I enjoyed it a lot for about ten years then it developed a problem and now it sits looking at me every time I'm down in the shop. Once it warms up the music is replaced by a loud squeal/shriek type noise. Is there a chance that a "re-cap" could solve this issue? I am going to make some room on the bench and make a list of all of the capacitors in there to order and look for any bad ones or other obvious signs of a problem.

It would be great to hear this again. Its been sitting for probably 20 years now. I hope its not just a paper weight

Any tips would be greatly appreciated.

Ryan

Hi all,
I was hoping I could get some advice on routing. I’m looking to build a pair of speakers with the IKEA blanda bamboo bowls.

Now I’ll be the first to admit I’m somewhat challenged when it comes to wood working ( and that’s been somewhat kind). 🙁

I’ve just got a plunge/fixed router and have a jasper speaker jig. Where I’m struggling is working out, how to cut out the speaker hole/recess given Its a bowl.
Should I build some sort of box around it with a hole in it level with the bowl bottom?

If anyone has built a blanda speaker (I’m using the large 11inch ones in bamboo) before or could offer some advice how best to router out a hole and recess for the 5inch driver that would be great.

Sorry for noob question but any advice would be greatly appreciated

Thanks Guys

I have a digital preamp with some built in dsp for volume eq etc.

I'd like to share power supplies with the tpa3118 chip amp. However, it is giving me a noise which I assume is some sort of clock interaction (much like 2 mono tpa3118 amps generate on the same psu).

Is there a good work around for this?

WTB Shigaclon, the best would be Shiga Mk.2 Black.

Together with CD mechanic or not.

Hello

Here's a post about analysis of the spectrum of distortion of intermodulation of loudspeakers (IMD) using my multitone signal of 14 non harmonic frequencies in a wav file.

Loudspeakers have two types of distortion: linear and non linear. The non linear distortion are the one we will test and are made of new frequencies in the acoustic signal of loudspeakers output, those frequencies was not in the original audio signal.

A way to measure it consists in sending two non harmonic frequencies, but only two frequencies don't represent a typical musical signal at all, and the normal use of the loudspeaker.

Another way to measure the IM distortion consists in replicating a more complex signal, and to measure the supplementary frequency level appeared in exit. The advantage of a multitone nonharmonic tones measure of the intermodulation distortions is that the signal test is large, more complex than the pure frequency used for the harmonic distortion or the two frequencies IMD measure. This distortion of intermodulation is therefore more representative of a typical musical signal, and of the normal use of the loudspeaker.

The signal used for the test is designated under the term of multitone, because it consists in a non harmonic frequency collection. They correspond to the big stripes on the picture of an analysis of the spectrum of distortions or distortion of intermodulation. Everything that is between these stripes is the distortion of intermodulation and the harmonic distortion; it is these undesirable signals that it is necessary to reduce to the minimum. Indeed, as for the harmonic distortion, the more the distortion of intermodulation is weak, the more the sound is clean and transparent. Contrary to the harmonic distortion the level of distortion of intermodulation is very correlative to the subjective sound quality.

To make this multitone signal test a low distortion signal is necessary, I have synthesized a low distortion multitone signal of 14 non harmonic frequencies in a wav file, (here's the frequencies;
22, 30, 52, 83, 123, 199, 316, 499, 802, 1248, 1998, 3152, 4997, 7997 hertz) and placed this file in this site web, so you can download it:

http://www.filedropper.com/g22hza8khzmultitone

To make the analysis of the spectrum of distortion of intermodulation while using my multitone signal of 14 frequencies, you can make a cd of it and use a cd player of the best quality, or you can use the wav file and an excellent sound card in full duplex mode and a software of analysis of distortion spectrum: Arta, SpecLab, Visual Analyser, ect... to see this distortion of intermodulation.

For the analysis of the distortion of intermodulation of a loudspeaker you also need a microphone of the best quality, you place the loudspeaker in a room that has the least possible reverberations, you can use a carpet and a thick curtains to decrease the reverberations.

I also include an image of the IMD of a very good loudspeaker using my test.

Bye

Gaetan

Greetings.
I was very happy with my Frugalhorn Alpair 7.3s until one of them suffered an untimely accident involving the better half and some enthusiastic spring cleaning. I’m saying nothing but she never really liked the aesthetics of the ‘horns, preferring the Metronomes that have been relegated to the office. I can see her point, our living room is 6m x 4m, and the speakers fire across the shorter distance. The 0.45m depth of the ‘horns meant they stuck out further than ideal, especially as they work best pulled away from the wall. So something with less depth was in order and, as the 7.3s are NLA, it gave me the excuse for a new build. EJ Jordan’s Eikona SL-A seemed to fit the bill in terms of size, with some good reviews out there.

The advice is for 12mm birch ply but I only had 15mm, so 15 it was. Apart from that they are as per the plans on the Jordan site. The covering is Furniture Marmolium because I had some left from another project - and it's lovely stuff.

When I first fired one up in the workshop on a little tripath amp and compared it to the remaining F'horn I was a bit worried about what I thought was a lack of bass. It turns out that the Eikona's are just less efficient than the horns and need a decent amp to drive them, and they are designed to work against a wall.

With them in position and driven by my Passlabs F5 and Topping DX3-Pro they go loud enough for me and and they go low. So low I don't feel any lack of bass. And the highs and midrange integration are as good as you'd hope for from a driver at this pricepoint. Actually no. I'm listening to the Unthanks' The King of Rome and I've got shivers down my back, you can't ask for more than that. Highly recommended, I think this lockdown's not going to be so bad after all. 🙂 All the best everyone, stay safe, Gus

OK, I give up. So many amps to build, Sissy Defisit, M25, Vfet, F7, J2 and few others....I am building separate Power supply. Hardly new Idea, but thoght I would start this thread to get ideas for most versatile one.

Will combine ideas from Eric, who shared with me his version and how it works.

Transformer, or Transformers will be wired in with junction blocks as I usually do, in event different voltage is needed on rails. This likely will not be too often, but am making allowance.

This way, cap banks and rectification can be reused. I try to always use 50 volt caps, to allow for possible higher rail voltages, will do same here. Connections to amp will be Power Con parts, ( hopefully have greenlee cutter from tube days in proper size already)connecting cables will be short and fat.

Final bank of caps will be in placed in Amp chassis, as I learned from remote tube amp power supplies I used to build. May even use junction blocks and fasteners to make those final caps moveable as well, may not be necessary since the are in addition to stout banks in power supply chassis.

Intend on dual mono, but with removable transformers would also allow single transformer applications if ever necessary. (Have some big honking SUM-R 1000 VA unit)

Any thoughts or ideas much appreciated, only want to build this thing once!

Russellc

Hello, selling list below , PM / email me for shipping calc :

Precision Devices PD153.C002 - 15" OEM studio woofer pair (100db , very HQ drivers like TAD 1601) , NEW BOXED, pair - 500Euro
Dayton audio PA200-08 PRO midbass 8" , NEW PAIR 90Euro
BMS 4538 , 1" CD , NEW PAIR 100Euro
SICA 60.38/N93 1" NEO CD, NEW PAIR 90Euro
SICA cd-120-44-640-poly CD ( DE250 equivalent ) , USED at Home , pair - 100Euro
SICA cd-95-44-n240-poly NEO CD, 2.1 TESLA, COPPER RING, used at HOME, Pair - 180Euro
Dayton Audio midbass DS215-08, used at HOME, pair 65Euro
Celestion CDX1-1425 , NEO CD, upgraded ( felt under the diaphragm fitted) , used at HOME, pair - 130Euro

Would swap to : PHL audio 1120/1130/1660/1500/1520

Thanks

I am looking to build a pair of bookshelf monitors for my digital piano. I am talking normal acoustic volume rather than rock concert levels 🙂

I have tried a bunch of commercial ones and they all have some clearly audible distortion in the 200-400hz region (this is totally absent through headphones). The distortion is quite prominent in the budget Focal Alpha 65, but still present, though much less so, in the eye watering expensive (1700GBP) Focal Solo6 Be. The distortion is coming from the drivers (I have taken the driver out of the Alpha 65 to check) rather than the enclosures.

I was thinking of the A12P in the bass reflex box on the Markaudio’s website. I am constrained to bookshelf size (they are to be placed on my piano).

Any views/advice?

Many thanks in advance.

The PCL82 was probably one of the lamest, dullest and unexciting one-tube amplifier of the sixties/early seventies.
It plagued many cheap TV sets and crap record-players of that era.

According to its datasheet, it was supposed to deliver 3.3W @10% THD with a 200V supply.
Very optimistic...
Even in sim, using exactly the parameters published in the datasheet, it struggles to arrive at 2W.
The reality is even worse.

It is thus a perfect candidate for a long overdue makeover.

I wanted to see how far such a tube could be pushed, whilst respecting all of the key abs.max.ratings, except for one.

The trick I used is to fit the tube with a cooling clip, attached to a large heatsink, exactly as for a transistor:



The aluminum clip is 1~2mm larger than the tube, and a home-made compound of silicone 145 (high-temp) and MgO ensures the thermal connection and the mechanical protection of the tube.
The heatsinking arrangement keeps the glass surface at ~60°C, instead of ~260°C under free air conditions.

With the max anode voltage of 300V and the max anode current of 50mA, the anode dissipation is 15W, compared to the 7W allowed in the DS: more than the double.

I have tested many amplifier variants, both in sim and reality. The final version is the best-performing in reality (not in sim).

The transformer is salvaged from a TV vertical deflection unit: its characteristics are ideal for for a medium-power SE amplifier.
It has a main, primary winding, a low impedance output compatible with 8 ohm, and an auxiliary reaction winding that can be repurposed as a UL connection.
It is not the first time I repurpose a vertical unit for audio duty: I also did it with a dedicated IC:
https://www.diyaudio.com/forums/chip-amps/280777-funny-chip-amp.html

This is a drawing of the transformer (a MBLE BT653): it withstands a secondary current of 1.7A without saturation, which is very generous for this application:



This is the circuit:



The supply voltage is 350V: taking into account the resistive loss in the transformer and the cathode resistor, it result in a 300V anode voltage.
At a THD of 2.5%, the output power is 5.8W. This is the waveform at the anode in those conditions:



At 3W, the THD is 1.1%, and 0.25% @1W.
The 3dB BW at 1W is 10Hz to 26kHz.

Here are some pics of the breadboard test:





Note that it is a true, bona-fide tube amplifier: no semiconductor cheat of any kind, not even a diode.

On google for Adam "A7x amp" it find this,



But here is what Adam have to say about their amps/D class on the woofer, and A/B on the tweeter,



This is prooly for S3x since is 3 way, but it should be very similar to A7x just 2 way, as far as i see in the first pic that is transformer based AMP, and here is what Adam says about their recent D class amps,

"The ADAM units use the new technology for both the amp and the power supply section (i.e. no more transformers) combined with state of the art input and filter sections to achieve the best in multi-channel active studio monitoring"

I'm a bit worried, i know there is no logic in Adam using the amp on the first pic, because is lower grade as far as i can tell, but i just want to make sure...that pic does not look like D class PWM amp to me, maybe it is from Adam A7? or maybe the site who is selling this stuff have put wrong picture? thanks guys!

Please help me if someone have opened or knows what exact amp A7x is using.

I have a pair of MX50se Amp kits. My not so well thought out plan was to build an Amplifier for my Motorcycle. Now that I got a pile of parts I realize I might be over my head. Can someone help me with a list of the other components I would need to make this work. I have a pair of power supplies 63V2200UF*8 for the kits. I also have a dual channel Mute delay speaker protection kit for it. Is there anything I am over looking? I have been looking for some written information but not having much luck. I've read and watched a bunch of videos and articles on this site and youtube. Not much help so far. Thanks in advance.

Hi All

I'm a complete newbie to this forum and I am looking for some help. I also know very little about electronics so please bear with me.

I have owned this amp for about 2 years, having bought it second hand. About 6 months ago it developed an intermittent fault - the LH channel cuts out or goes very quiet and only comes back if I nudge or tap or press the front of the case. At first I thought I needed to tap the volume or balance control, and so thought it might be those potentiometers but have realised that I can press anywhere on the front or top of the case and it resolves. I have taken off the case top and can see no obvious issues with loose wires etc, and have found that I can make the LH channel go and comes back even by pressing on the rear of the circuit board with a screwdriver. It's as if there is a loose connection somewhere which is highly sensitive to movement of the circuit board.

The issue is present on the same channel on both sets of speakers.

Any advice would be gratefully received.

Cheers.

Hello everyone. Been lurking for quite a while, decided on most things, need advice.

Midwoofer: 2x Faital Pro 10RS350 in D'Appolito config
Tweeter: Faital Pro HF10AK or HF108 (can get the latter real cheap) coupled to B&C ME45 horn
Box: 30mm plywood, Vb=60L, ported, Fb=35-40hz
Crossover: 3rd-4th acoustical at 1300-1500hz (I am lucky to have a friend who uses an active crossover for his speakers, going to visit him with mine and play with the tuning before making a passive)

The biggest concern for me was finding a 10 inch midwoofer (not willing to go any smaller) that wouldn't break up until 2khz and had Fs<45hz. I think the Faitals would do the job pretty well and I can get all four for less than $450, but I'm open to other suggestions in the same price range.
Also, is it a good idea to calculate the passive crossover based on the parameters calculated with my friend's active one?

Current speaker box made in Speakerboxlite looks like this. The horn will be located between two midwoofers.

Thoughts?

hello all,

has any one tried this in an amp? IXYS depletion mosfets are now available for this, so i would like to know from those who tried and what the results were...

Lots of random stuff. Only selling all at once. $100 or best offer. Shipping at your expense however you want it shipped.

List of some of the bigger things.

1. 4 input, 2 output selector board, populated with knob and ribbon cable
2. CRC power supple PCB with heat sinks
3. (2) Amb/Ti Kan alpha 24 amp boards. Fully Populated
4. (2) triad 2x12vac @ 25va toroidal transformers
5. (2) RJM audio VSPS boards, populated
6. Four gang 20K teradak stepped attenuator
7. (2) IEC
8. (10) 35A 200V bridge rectifiers
9. Variety of molex headers and pins
10. Variety of rca and xlr panel mount connectors
11. Bunch of mosfets
12. An unfinished Telos amp with heat sinks and hardware and power cable

I have about 100 (+/-50) of each of these die cut gaskets.

4"

Designed for a Seas MP12VC plastic midrange. OD 120mm. ID 95mm. 2mm thick. No adhesive. Four holes are already stamped for the driver screws.

8"

Designed for a Vifa 8" cast frame woofer. OD 222mm. ID 198mm. 2mm thick. With adhesive on one side and peel off backing. Six holes are already stamped for the driver screws.

"Buyer" pays all shipping costs. Will not separate.

Morning all.
You’ll probably confirm that I do have a screw lose when you read this .
I have my Tannoy SRM12x speakers that I recapped back in January with equal value Ansar supersound capacitors , and gave them 3 months of daily usage to burn in but I was never happy with the sq so 2 weeks ago I put all the old capacitors back in and hey presto the magic was back , some had strayed from 6.8uf to 7.1uf ( I tested them all when I initially removed them ) . So I now have all 8 identical nos caps on their way to me ( they’re Philips) but I need to get 2 identical ones seen in the picture, there is no brand name on them , they measure 27mm x 8 or 9 mm and have 2.2 J 100 printed on them ( and the little wave thing )
Anyone know this brand ?
Ps : I am fully aware that I can replace them with similar ones .