Hi. Looking for somebody to fix Linn CD12. Looks like the famous Brilliant power supply is kaput. I changed the caps, but it is still dead. Thank you

Hi All,

So I've spent the dreaded lockdown period turning my passion for speakers into something that can hopefully generate some revenue on the side and fund future projects. I've built myself a website and a YouTube tutorial to go with some small Bluetooth Kit speakers I'm selling (easy to make with the intention of getting people into the DIY Audio game).
JCR Acoustics – Science Employed by Art
Make a DIY Bluetooth Speaker With Just a Screwdriver!? - YouTube

I'm asking to see if anyone has any tips or experience in doing something like this. The feedback I've generally got is the content and product is good - but it seems my outreach is very slow and I've yet to make sales outside of friends and family. Does anyone have any pointers - besides to make more content (I think this may be the key here for YouTube) and keep pushing my Instagram and Facebook I'm stuck for more ideas. Once lockdown lifts in the UK I'll also look to approach some craft stores if they've survived.
JCR Acoustics - Instagram
JCR Acoustics - Home | Facebook

Any tips would be greatly appreciated. I know this isn't really what the forum is for hence posting in "everything else" but it could be a great discussion as I'm sure there's a whole bunch of people itching to do something similar. Also please feel free to check out my content and show some love! 😀

Thanks All!

Hi guys, I want to step up the output from my cassette deck into my Korg DSD recorder and would like your advice about using the Lundahl LL1545a to do the job. I am competent at soldering and can follow a diagram but clueless about impedance transfer. The cassette deck has 2.2kohm output impedance - unbalanced RCA - and the Korg has 50kohm input impedance unbalanced. The LL1545a can be used 1:2 to double the voltage - 500mv to 1V in this case. Any comments would be useful thanks.

can anyone help. i have a 3 way crossover and the output from the tweeter is too loud. i have bought some different value resistors to put in the line to the tweeter but dont know how to wire them. do they go in line or across from positive to negative. thanks for looking

Has anyone cloned a merlin VSM?

Merlin web site

Or if not, does anyone have dimensions of this speaker, or actually have this speaker and willing to cooperate in providing info on it?

See ya in a few hours!

Hi there,

This is my first post and first time trying to build a complete speaker from scratch.

I have embarked on a new project to build a sort of transportable speaker. So it should be able to easily fit in a backpack.
For that reason I chose the Dayton Audio DMA80-8 3". I want it to pack a bit of power so my idea was to put 2 of those and the corresponding Dayton Audio DMA80 PR3 passive radiator.

I am having a hard time finding resources on how to calculate the right box enclosure for this setup though.

So I have 2 questions :
1. Is this design worth it ? (2 full range + 2 PR)
2. How should I go about calculating the enclosure size ?

Thanks a ton for your help!

I have tried the PSU Designer II but don't see the option to enter the PT amp current

Assume: the design requirement is 40mA
With (285-0-285) at 250mA and (285-0-285) at 120mA and tube 5AR4. Would the PT with high current will give out more voltage? I am not sure how to calculate that. What voltage ranges require R at 10w and 3w?

I'm after a Sanyo M9815K service manual and or schematic. I'm trying to restore this ancient Boombox for a guy down the road who loves it so that's good enough for me to restore it for him for free. Some info on it would be a big help that's for sure and greatly appreciated!😀

These have been claimed, no longer available

Pictures in this thread: FS: Speakers: dMar-Ken7.3 Slim CGR MarkAudio Alpair 7.3eN

The actual drivers have already been sold.

I still have the enclosures. They were made from a flat-pack that Planet10 made for me. Very nice high-quality birch plywood, precision CNC cut.

They are coated in Duratex.

Free for pickup! I'm in the western Chicago suburbs.

If you're outside of the Chicago area, and really, really want these, PM me. I will ship, but you must do the work of creating the shipping label and paying for carrier pickup.

Basically, I want to do the least work possible to get these out of my house, but keep them out of a landfill.

Thanks!

SOLD

Trying to clean house while recovering a bit of sunk cost.

Five items, selling as one package:

• WaveIO XMOS USB to I2S/SPDIF board
• Allo BOSS DAC and Raspberry Pi 2
• DIYINHK LT3042 Power Supply
• DIYINHK AK4493 DAC
• DIYINHK ES9018 DAC

All except the last two DIYINHK DACs are tested/working. The last two items, I built but don't recall if I ever actually tested them or not. They "should" work unless I made an assembly error.

Asking $75 for the whole lot, USA shipping included in the price.

Sorry, I can't do international shipping at this time.

Thanks for looking.

I have this Nak MB10 which sounds good as a transport but skips pretty bad. I heard along time ago that there were some type of factory modification for the MB10 to address skipping. Any former Nak techs that remember this? It plays fine with a perfect disc but light fingerprints or even miniscule scratches that most other players will track makes it skip bad.

Why we need to check on the harmonics and THD?

In the past years, I built amplifiers according to the schematics and kits. Also, I believed that using those high end audiophile components will yield better sound from the amplifier that I built.

Few years ago, I heard from the electronic engineer who had been working on design and calibration of electronic amplifier and equipment that it is important to minimize the distortion of the amplifier in order to get the best sound out from it. I wasn't sure about it because I didn't have the equipment for perform such measurement. Luckily, I bought a Keysight oscilloscope last year and found the Soundcard Scope program for PC that I could have the spectrum analysis function and THD measurement.

During the past 10 months, I tuned most of my amplifier for the best THD figure. Now they sound so good that impressed me so much.

I really enjoyed being able to see all the new-activity posts on all the threads I DON'T subscribe to. And to be able to get more than one screen full! But it seems this clicky linky has moved or disappeared ...? How does one obtain multiple screens worth of brand new posts?

The forum's search function has been identified as potentially being a significant contributor to the uptime issues over the last 24 hours. Searches for common search terms with large result sets are causing serious issues with server load.

Search will be disabled for the next 24 hours while we monitor the situation.

In the meantime please use Google for your searches using the search format:

site:diyaudio.com beer

hello

SME M2-12 tonearm for turntable

i have a like new condition complete with box / packaging and oem parts
i bought it some time ago, i tried to use it ,,but it is complicated to installed with my current setup, so i ended up never used it before,

it is more rare version of 12 inch tone arm version, NOT common 9 or 10 inch arm

i can meet in washington state and oregon state in person for safe transaction

Hi,

I would be interested in a DAC module with 1x AK4499EQ or better with 2x AK4499EQ in mono mode. Input only I2S to connector or pin header. My vision is, that on the PCB desk would be only 1 or better 2x AKM, voltage control, I2C bus and analog stage. I2S input, I2C bus not isolated, 4 layer PCB for simple layout . Here is my old unfinished project, how I imagine the implementation.

I would like to ask if there would be interest in such a board and if anyone could do a professional design. It would be good if there will be possibility of distribution of the board with soldering AK4499EQ (pad bottom side chip). Even better with the possibility of professional soldering was all SMD and THP components. It would be a widely usable module. I'm willing to pay for such board and I need a few pieces. I would probably be able to design it myself, but I don't have the possibility of using of automatic assembly machine and reflow.

Could someone du it?

Hi everyone,
On my first amplifier repair. It was previously repaired by someone else, and when I opened it up I found that the output FETs were shorted on the negative rail. I removed the rectifiers and the power supply seems to be doing its job correctly. Before ordering and installing output FETs, I checked the gate signal. The side that had the shorted FETs has what looks like an ac wave in it, the other side seems good. I checked my 5v regulator and noticed it has a really dirty voltage coming in and out. I am not sure of what my next step would be. Am I able to remove the voltage regulator and see if that straightens out my issue, to help me see if its before or after? Would love some advice! I'm going to be at guard drills all weekend, but would like to be ready when I come home so I can figure it out!

Thanks in advance

Pic 1 is the dirty gate signal
2 is the dirty voltage regulator
3 is the 12v output from the transformer
4 is the other leg of above transformer
5 is the diagram from transformer to voltage regulator.

I found the diagram for a Massive SL1500 to be identical for my amp, same values and identification numbers, so that's the diagram I'm going off.

Hi

I have so far not found a specific thread that discusses Preamplifier circuits so i thought i might make one for SS pre-amps to get tip's about schematics, PCP's components and discussions how and why.
This is more of a general thread so RIIA amps are welcome but not the main topic.
I know that most products now comes with build in pre-amps but this is for those that want to build their own stuff and needs a pre-amp to go with it DIY CD,DAC,LP and other equipment. and i want alternatives and to get my hands on something really nice like we all want.


The Simple Rules

1. this it NOT a SS vs Tube vs D-amp thread, everyone has their own tastes and here its SS. this also includes OPA flavours and other components
2. Be nice, not everyone knows everything so don't ride in on a high horse.
3. Sharing leads to progress, if you know help others understand.
4. If possible, components that are still manufactured. No one wants to have to buy a 50$ out of production transistor from a dodgy seller.
5. I have OCD and a list with only 4 points made me uneasy and i like the number 5.

- Hello , I could use some help from anyone who has experience with both the BMS4592ND-Midrage and the BMS4592ND-Coax how would you compare the sound, do you give up anything by going with the 4592nd-Coax , does one midrange sound the same as the other? -

Are soundcard like this (CM6206) can be use to measuring speakers?

Someone say for measurement can use soundcard with line in jack. He recommend Behringer UCA202 but in my city the price is too expensive. Can I use this cheap soundcard?

The soundcard
https://www.jakartanotebook.com/ima...-51-suround-usb-untuk-laptop-or-pc-blue-4.JPG

Hi¡

I have a kicker zx350.4 with crispy distorted and very low output.

Ps only does +-25 volts. Tl494 have only about 6 volts at pins 8 and 11. Pin 12 had 12 volts. Tl outputs have about 1.5-2 volts so the ps dont raise the rail voltage.

What is the correct voltage at collectors? Pins 8 and 11

Thanks

(Qty: 5) Gershman GA-10 ten-inch fiberglas woofers.

In original booes, with packing materials.

Never used, except for brief T/S parameter testing.


Mint condition.

A quick test with a Dayton Woofer Tester yielded
the following partial T/S parameters:
Re: 5.055 Ohms
F(s)=43.07 Hz
Q(ts)=0.726
Q(es)=0.843
Q(ms)=5.194
L(e)=1.357 mH.

Gross Weight: 8 lbs
Box Dimensions: 11.5" x 11.5" x 5.5"

According to Ofra Gershman, these were used in the GAP-828.

I think they may also have been used in the SW-1 subwoofer and/or the X-Cube.

Might make a great open baffle system with the Qts near 0.7.

Obviously these would be invaluable for replacing an existing woofer in a Gershman system.

Gershman sells them for $CAD 285.00 plus taxes and shipping.

Make an offer.
Prefer local pickup in Toronto, Canada

Here's the fault details my amp was getting.

Strong buzz from both speakers, that got weaker the more the amp was left on, and didn't change with the volume control.
Pressing the "Direct" button reduced the hum by under half.
Loudness button didn't effect it.
You get this whatever input is selected, and it doesn't matter if something is connected to it or not.
Pressing "Tape Monitor" makes the tone a bit deeper. Maybe a bit louder too. Balance hardly changes it, and the bass and treble have a very slight effect.
It doesn't matter which set of speaker outputs you use, it will be the same.
The sound quality when playing anything is still good, and at higher volumes the buzz disappears into the background.

I replaced the two big capacitors on the main board, but this didn't change it. I searched this forum as good as I could using Google (search system on site suspended at present), and didn't find anything. I did get some information from another forum that put me on the right track.
I replaced C613, and C614 (470uF, 25V) and this has cured the hum. I believe these are the smoothing capacitors for the 15V circuit.

I did download a Service Manual with schematics from another site, but it was so bad I couldn't read the writing. If anyone has a link to a good copy, it would be nice to have it.

Please see attached pictures to help.

Regards, Rob

Looking for a two channel chip amp kit (or assembled), LM3875, LM3886 or whatever. I want to get 50 watts or so per channel.

Thanks.

My Pass Labs XP20 preamp is designed to be powered on all the time. Does it matter at what volume the preamp is set when not listening to music? And for electricity usage, does it matter if set to 0 or 40, or is the power usage the same?

Hi Guys,

I've come into possession of a Denon UDR-F88 cassette recorder, the thing is the last person who had it thought it was a CD player and left a little gift inside for me, (wondered what the rattling was).

Long story short, the right pinch roller has broken, (clip that holds a pressure spring on snapped off). I've tried gluing it, but I'm not holding out any hope.

I've been down the rabbit hole of trying to procure a service manual for the deck, but can find any free ones, any paid ones are pretty pricey and I can't guarantee they'll still exist after I purchase it.

All I really require is the part number for the broken pinch roller so I can get a new one ordered, hopefully someone still has one in stock.

Can anyone help?

TIA,

Pagey

- got a message asking what I thought of a design - the sim looks pretty good but can't see how he got the input for hornresp.

I don't currently have access to hornresp. It would be good to have someone assume his drawing is proportional to the size he wants, scale it to the frame size of the driver shown, then run that with Kappa12a' parameters through hornresp to see what that little cabinet would actually do.


Can you make sense of his input screen? - How much volume does it say the enclosure takes? What he drew only looks to be maybe 2 cubic feet worth of airspace.

For sale is a pair of NLA Peerless HDS Exclusive 8" drivers. Amazing driver works best in a cabinet 50-60L tuned to 30Hz. Perfect condition other than marking around mounting holes as shown.

Price is CAD$160 (USD$120) plus shipping from BC, Canada.

I want to build 2 subs and drive from 1 amplifier.
Which would give the best sound.
2 x 4 ohm drivers connected to give 8 ohms or 2 x 8 ohm drivers connected to give 4 ohms I.e series or parallel my amp can drive either.

Hello,
for sale a pair of 600ohm LCR RIAA inductors, directely from Japan.
More info:
EMISUKE???????
http://emisukeaudio.sakura.ne.jp/EM-TUBE_EQ3_KAI.pdf
110 eur plus shipping and PAYPAL fees
Best regards
Guglielmo
Italy

Hello,

I am looking for a Allo Digione. Thanks !

Regards

As components I have to buy cost only $10, a few dollars remain to reach oversea free shipping ($45).

usually, you choose opamps according to projects you have in mind. But if you want to have some samples in yours drawers for prototyping, wich references will you order ?

Just bought a pair of defunct Mackie monitors for less than $3. Mackie MR5 Mk2 Reference Monitor (Single) | Music Matter The vendor believes he's blown both woofers. (They are supposed to be protected).

From my perspective I see two very viable plate amps.

My first question is: other than installing a passive coil to create a low-pass filter what can I do to change the crossover point?

My second question: The Mackie contains two amps; 55w bass, 30w treble. Any ideas on how I can utilise the second amp?

A circuit diagram is on page 13. https://www.fullcompass.com/common/files/14072-MR5MKIIOwnersManual.pdf

Hello!,
I've bought on AliExpress my TDA7492p amp with board and everthing (link here). There is a Aux Input but this wont work without a bluetooth source.

For example if i plug Aux without bluetooth devices connected i hear nothing. But if i pair a bluetooh device and play something then i plug aux playing other thing i can hear both. Even ehen i turn on the amp with AuxIn when the amp is looking for a BT device make a noise and when noise is played i can hear the Aux.

BT Device Paired, not playing = no Audio from AuxIn;
BT Device Paired , playing anything = Normal Audio on AuxIn;
no BT Device Paired = no AuxIn audio;

what can i do or what i'm doing wrong, my priority is Aux, i want use amp on pc over aux BT isn't my necessity.

i'm not sure if what i write is clear and i can record a video if you want.

Hi All:
I have a problem with my TD147 Jubilee. The auto stop doesn't work properly. Since this is one of the reasons I bought this 'table, I really want it to work as designed. So...

The problem started when the LM324 quad op-amp (Z101) fused and took out one of the rectifier diodes in the power supply section. This presented ~20VDC to the whole circuit and cooked the MC3400 JFet op amp (Z102), the BC547a transistor (T101), the 4.7V Zener (D108) and the arm position LED (D109). All of these have now been replaced and the board is behaving just as it should, with one exception. When the arm crosses into the lead-out groove it is supposed to drive the transistor output high which releases the solenoid allowing the arm cue to be in the down position, thus lifting the arm and coincidentally shutting off the motor. With mine, as the cartridge crosses the lead-out groove, nothing happens. However if I move the arm briskly across the same area, the arm cue lifts and the table shuts off as designed.

When repairing the damage described above, I was unable to find an exact replacement LED, so have used a 3mm warm white led with a 3.3k dropping resistor. This seems to be workable although a bit brighter that the original. I can measure the voltage rise on TP4 specified in the service manual, however it doesn't seem to get all the way up to the +15V the manual specifies. It seems to peak around +9V. My meter isn't fast enough to display the voltage when the arm is swung briskly through the lead-out area, but since the auto stop triggers as designed, I must assume that that motion is generating the required voltage to the base of T101 through IC101/3.

Have any of you had / seen / fixed this problem or have any idea what I am missing? I would be deeply grateful for help with this.

Best regards all
Jess

Hi,

I have a couple of Abletec Anaview ALC 0100-2300 class D amps. These are 50wpc@4ohm and can work in BTL for 100w@8ohm.

I am feeding this amps with an ADAU 1401 DSP with an output sensitivity of 0,9Vrms.

My woofer and tweeter are both 8ohm, so when working in stereo mode I get around 25wpc or something like that, which considering the poorish sensitivity of my components, they don't get too loud... but it's OK.

The thing is that I want to try the BTL mode and get 100w@8ohm.

According to the amplifier's spec sheet, it can work in BTL mode with single ended or balanced input signal. I am using a single ended signal. I wired it just like the diagram (pin 12 and 10 are input + and 8, 9, 11, 13 are ground), and shorted the "CONN5" like the PCB says.

The amp sounds good in BTL mode but it's not louder than the stereo mode, which is weird as it is almost 4 times as powerful!!

I am making something wrong? I am understanding something wrong?

Looking forward to your help.

Good evening everyone. I seem to be having trouble getting the right box volume from a program am using? I know Visaton has some box designs but, am looking for a stand mount or a larger book shelf. I know louise from omega loud speakers used two special scan speak vents 2 per box on the back side. Can someone help me out? Maybe am not seeing or doing something right? Thanks Jeff

Just wondering if anyone out there has heard these two drivers and could make a comparison. Thanks!

great floorstanding speakers
tdl - Google Photos

Transmission line cabinet from TDL RTL3

all - Scan Speak Revelator series speakers.
1st order filtered crossover for woofers and 2nd order for tweeter

88.5dB 4ohm.
12awg Wax foil coils, solid core annealed silver wiring, wbt copper gold binding posts
I used them for 12 years as replacement for Sonus Faber Cremona. They really sound amazing.

1300 eur (speakers are located in Warsaw, Poland).
Can ship anywhere in Europe by dedicated courier for around 100 eur

Hi I am currently building a WMTMW system, originally it was a mtmw, Own compatment MTM, with seperate comparment for Lab12 as bass woofer crossover frequenecy is 200hz -300hz.

becasue I am going WMTMW and since the woofers would be sharing the same compartment, I was thinking to reduce the woofer size to around 8 to 10 inch but maintain the charactersitic of lab12 woofer.

So good suggestion would be appericate

Hello everyone,

due to Covid I have too much spare time, so I decided to do a project: give my old NAD 216 poweramp a new enclosure.

Electrically, I didn't make any changes. I only de-soldered the signal wires to the power amps, and removed the (audio) inputs from the power supply board because with the new enclosure these will be relocated.

Before mounting it all in the new enclosure I remade all connections and turned the amp on. After 3 seconds it switched itself back off. So, the protection circuit has been activated.

There are 3 (groups of) connections between the power supply board -which also houses mute, protection etc- and the left and right power amps: a 7 pin power connector, amplifier output (4 wires) and a signal input connector (signal and ground).

After some testing, this is what I found out: with both power and amp-out connected there's no problem. With 1 of the 2 inputs connected, no problem. As soon as I connect the second input to the power amp the protection gets activated and the amp shuts down.

Just for the heck I tried something else: connected the left input to the right channel power amp and right to left. To my surprise it stays on this way. If anybody has any ideas about this...please share.

Meanwhile I will put the amp back together and hook it up to a source and some speakers, see if it actually plays music.

Hello

Anyone know of a device that acts as an LDO (3v3 preferred) and as a supervisory IC in one? Im looking for something that could do the job of activating itself at a prescribed voltage threshold and doing the regulating work itself. I recognize that I could use an exterior supervisory IC for an LDO with an EN pin, but just polling here. Also, does anyone know of a supervisory IC that has a lockout function that needs to be power cycled in order to reset?

Muchas Grac
S

Looking for one or two pair Dayton Audio RSS390HF-4. Paying with paypal.
I prefer a seller from Europe. Please PM me.

Thank you!

Andre

Hello, i have for sale this jesen transformers that can be used as output of the akm4493 dac boards.
The dac boards are one with film caps and the other with tants and expensive rubicon pml cap.
The sound is very good. There is a dac selling on Austrália by the name of gieseler that uses the same transformers and dac chip.
Accepting offers.
Tks.

View attachment 891332View attachment 891333View attachment 891335View attachment 891334View attachment 891336

Sorry for bringing up this old topic. But I recently built the Idunn as I don't have much time to design a speaker from scratch. I did some basic testing with an old Liberty Audio suite which seemed to correlate that the speaker, as good as it is, has something wrong with it. Contrary to what other have said the speaker has a very extended bass with excellent detail and level. The problem is that it sounds too forward making solo piano sound "chrome plated" on the higher notes. However cymbals sound a touch too low in level. I have done some very quick changes by adding an extra amount of bass inductance (externally) but the hump remains. Any ideas what is wrong please?

sale - Google Photos


duelund cap 0,47 50eur [great for spdif cap]
jensen silver 0.1 40 eur [great for spdif]
6f6 nos sylvania pair 50 eur
6v6 FIVRE nos pair 50eur
6f6 Marconi NOS PAIR 50 eur
quad of e182cc tubes 100eur
E288cc tube 40eur
e88cc POPE pair 60 eur



cerafine cathode capacitors
SIEMENS Sikorel capacitors 10000uf 4pcs

and more more

Hello
Sorry for my English level because I live in France !😉
I have an amp REGA Mira 3 that is broken.
The 2 fuses (2A) at the power supply input blow (fuses like small resistance not easy to find as a spare and to replace) but the problem is not there.
I am looking for the schematic to fix it.
Each time the power is switched on, the fuses immediately blow. So there is an immediate short circuit (power transistor in shortcut ? )
What is strange is that the problem suddenly happened overnight without giving any sign of problem previously
Thank you for your helping
Regards
Stephane

I have Koss DJPro100, 38 ohm, 99dB SPL, and that is the only specs I have.

If I want to build a small amplifier, how do I know what the max AC current is?
If I put 38V on 'em, drawing 1 amp, that would be 38 watts, but I'm pretty sure that would fry 'em.

Ok - so I have a low level hum ; that was previously a high level hum....it was solved by my repairman by dressing and moving an internal heater cable to a new orientation.

Oh and my repairman is from now on going to be ME I think 🙂 after my latest experience with help from everyone - thanks!

The cable takes DC heater to V4 across the underside of the amp, and it got moved during a recent repair, then twiddled to a lowest noise location and tied in place.

V4 hums when you touch the glass, which reduces but still hums if you touch the chassis and the glass of the valve. No other valve does this in the amp

I can't help but think the two are related, and this is still introducing some residual hum?

Any ideas?

Good evening everyone, thank you for accepting me into your forum. I hope to learn alot while I'm here. I have a rather strange question for you all but it's really been bugging me. I won't go too much into detail but a drug dealing couple live in my street. For the longest time it's only been the woman with her kids but her drug dealing boyfriend started staying with her and he's been acting very strange. Keeps pacing up and down Infront of my house. We don't share a wall so I think it's too hard for him to try hear me but they parked their car outside my house for four days straight and something is telling me he somehow was listening to me. Money is no problem for these people. Could he have rigged up a mic inside his car and was listening to me? The car is 10 metres from my living room. I know it's a bit "out there" but believe me when I say they are drug dealers. Is it possible? Thank you in advance for any help

I just got this nice preamp. Not sure why so many have hate for them, but whatever, their loss. I put it in the tape monitor loop from ye olde marantz 4220, which has been my main amp for the past 18 years or so. I can’t hear anything different when it’s in the loop, Other than a little scratchiness on the tone pots (to be expected). I’m sure the phono sections could use an update, it’s got a fair bit of noise when all the way up, and we’ll see how nice it sounds. All in all, I’m not sad for the purchase. I needed something to drive the HK citation 24 that I’ve been working on, so that I can eventually get to building my take on the IDS-25 speakers, and this fits the bill for now.

So the thing I’m wondering about this at the moment, is where to find the brackets to rack mount it. I have a couple of old relay racks, one currently serving as the stereo cabinet, and would like to mount it properly in there. I can make my own brackets from aluminum angle stock, but it’s not 100% clear to me how they would get mounted to the preamp cabinet. There are two holes in the panel extrusion that look like they could be tapped, but currently there’s no threads in there. Seems odd that the front of this would have a gap like that, but it’s all factory as far as I can tell.

Anyone have one of these they can take a picture of how the brackets mount.

hi.i was wondering if any body has tried out the new dx super x amp? there are a few you tube clips but are mainly in portuguese , i have built some of carlos,s amps in the past and amazed of the results , i have emailed carlos ref to pricing and 2 x pcbs (fully populated) for around £180 inc postage ! if like me enjoy building amps usually on a budget then you know its a biggy ! i am tempted to bite the bullet and order a pair but would like to have some feed back from others before i part with my hard earned lolly thanks

I have always received generous and helpful responses to my posts on DIY Audio, so this post is my effort to contribute something that might be of value to some members.

I suspect that I may be like some of you in that I buy a speaker driver about which I have read good things but don't build with it for some time due to the daily demands of the life I lead. I have collected four full range drivers in this manner, and, having decided to finalize my plans for each one and actually BUILD some speakers, I chose to do a listening comparison test to enable me to choose the best use for each one. Please note that the review which follows is based upon my own listening preferences and hearing (I can no longer hear anything above the low teens kHz in frequency). I enjoy a wide variety of music and have attended many live concerts (mostly of classical music, including orchestral, choral, and chamber music, as well as jazz), so I know how music, voices, and instruments sound in various live settings. I have heard many different audio reproduction systems, and over the years I formed a preference for a sound which I describe as warm, yet clear. I am very sensitive to upper midrange frequencies, and I tend to dislike any component or system which produces a sound which is hot in the upper midrange. Please note also that I do not say that my preferences should be your preferences, nor that my impressions should be yours as well.

I obtained a piece of 4' by 4' (122cm by 122cm) plywood which is 1/2" (13mm) thick. I surface mounted one each of my four full range drivers in a square arrangement close to the center of the baffle with the center of each driver equidistant from the baffle center. I did not chamfer the back perimeters of the mounting holes and did not attach any stiffening braces to the baffle. The baffle rested upon the floor at an angle that put the center of the baffle on axis with my eyes as I sat in a chair at one meter distant from that center. It is possible, perhaps even probable, that this arrangement produced sympathetic resonances from both the baffle and the other drivers, and though this was not a scientifically controlled test, I believe I can claim that the drivers were tested under identical conditions.

I have a stereo receiver with four speaker outputs in an A/B/A+B arrangement. I connected each speaker output to a different driver and used the speaker selection switch together with the balance control on the receiver to isolate the audio output first to one speaker, then to another, in a more or less random manner, always knowing to which driver I was sending the audio. After forming impressions of each one, I then switched the audio in a purposely directed manner to compare each speaker to each other. After listening to each speaker at an equal level setting on the receiver, I then tried each one at an increased level and subsequently with a bass boost from the tone control on the receiver. I listened to each speaker both on axis and off axis at an angle I believe to have been about 15 degrees. One of the drivers produces an SPL significantly higher than the other 3 (about 3dB). I tried to adjust the volume downward as I listened to this driver in an effort to equalize the level to the other drivers, but as I formed my impressions I believed that I could successfully compensate for this difference and simply left the volume level the same for all the drivers. The music I used for the test was a mono recording of "Sgt. Pepper's Lonely Hearts Club Band" by the Beatles. I chose this for a variety of reasons. It is a recording to which I have listened for years on a variety of sound systems and with which I am very familiar. It has a large number of musical sounds and effects, with vocals, guitars, drums, pianos, electric organs, harps, clarinets, string ensembles, full orchestras, and even animal and crowd sounds, so it provides a good sampling of the variety of audio which a speaker driver might be used to reproduce. It is a famous recording which many people will have heard. Finally, it is a mono recording, so each speaker would receive the same signal as I switched between them. I played the recording all the way through twice and tried to give equal time listening to each speaker.

The four drivers I tested are listed below with the factory T/S numbers I believe are relevant to this test. I have tested each driver with the DAT system, but I list the factory numbers to avoid any confusion or disagreement engendered by home testing. I did not try to perform any electronic frequency response analysis. I simply listened.

Tang Band W8-1808---SPL 93dB, Sd 220 sq. cm, Xmax 5mm, Fs 45Hz

Tang Band W5-1611SAF---SPL 90 dB, Sd 94 sq. cm, Xmax 3mm, Fs 60Hz

Markaudio Alpair 10P---SPL 90dB, Sd 88 sq. cm, Xmax 7mm, Fs 42 Hz

Tang Band W5-2143---SPL 90 dB, Sd 94 sq. cm, Xmax 2.5mm, Fs 55Hz

The drivers are listed in the chronological order in which they were purchased.

Tang Band W8-1808 (paper cone, whizzer, phase plug)
It was immediately apparent that this driver has a frequency response which rises toward the upper midrange and treble. I listened to it on axis for this test, but if I were using it regularly for recreational listening I could not listen to it on axis with any music which has much high frequency information. Off axis by 15 degrees it improves considerably and produces a sound that is smooth, detailed, and a pleasure to hear. Given the fact that it is a larger driver than the other 3 it is no surprise that it produces more bass response (with the bass boost on the receiver, quite a bit more). The character of the sound is very much the same at low and high listening levels. It was interesting to discover that the rising response on axis was not objectionable on songs that did not have much high frequency content, such as "She's Leaving Home" and "When I'm Sixty-Four". The sound on axis was very good on those.

Tang Band W5-1611SAF (polypropylene cone, phase plug)
This driver sounds somewhat dull compared to the other three. Both on and off axis the highs are not as pronounced. Other than that, it produces a nice sound that is not objectionable in any way. It is one of the two drivers that produced the least bass response. The sound really improved with the higher listening level, with the highs becoming clearer and the sound being better balanced all round. I don't know how to account for this other than that it may have been an effect of the Fletcher-Munson curve. I think it is a nice driver, but the other three produce better detail on a variety of sounds.

Markaudio Alpair 10P (glass fiber and paper cone, shallow profile)
This is a very versatile speaker. It sounds good on a variety of material and produces a wealth of detail. It's sound on axis is detailed, clear, and comfortable, with no upper midrange screeching, and the off-axis sound is essentially the same. With the bass boost it produced a bass response second only to the W8-1808. Compared to the other three, it has a slight coloration that I can only describe as an "Aw" sound, as though someone were speaking through cupped hands. I suspect some lower midrange resonance is responsible for that coloration. The sound at the lower level was clearer than the sound at the higher level, which by comparison had a "congested" quality, sounding like too much emphasis in the broad midrange. I thought of this driver as the best full range speaker I had heard until I bought the next one on the list.

Tang Band W5-2143 (bamboo fiber and paper cone, phase plug)
This was the most recent full range driver about which I read and with which I was intrigued, so I decided to give it a try. I'm glad I did, because this one takes the crown as the best full range speaker I have heard. Compared to the other three, the impression I received as I listened was similar to that of a good pair of headphones. Smooth yet detailed, with no part of the audio spectrum objectionably pronounced, clear and warm but not bloated or congested, it sounds the best on the widest variety of material. Though the bass response with the bass boost was probably the least of all four, the tonal balance on axis was the best, and it sounds essentially the same off axis also. And, though it may seem to be a logical incongruity, the sound at the higher level was the same, only better. I really like this speaker.

I think each of these drivers produce good sound, and I think I could be content with any one of them if I were limited to using only one. Each has its individual strengths and weaknesses, and I hope to use each one in a way that will maximize its strengths while minimizing its weaknesses. These are my decisions regarding these drivers:

Though the W8-1808 is the only one I would consider using as a true solo full range driver (in a bass reflex cabinet), it will see duty in a sealed box FAST construction with a bass driver providing the low end. I will listen to it mainly off axis.

The W5-1611SAF I will use mounted in a bass reflex box as a utility speaker for the garage or an ambient speaker elsewhere.

The Alpair 10P will be used in an open baffle FAST construction with woofers on the same open baffle.

The W5-2143 will be used in yet another FAST construction which will be meant for close field (one meter or less) listening.

Please keep in mind that I am a music lover and not a speaker builder by profession or long experience. The number of speaker drivers I have heard and evaluated is not that of many members on this forum, so I offer my opinions with that qualifier. These opinions are valid for my preferences, and, I repeat, I don't expect anyone to agree with my opinions or share my preferences.

I have a Rockville RX MD3 thats heating up the rail caps which leads me to believe there is a drive problem.

I have isolated the current draw to the audio section.

Does anyone have a diagram of the driverboard in the audio section as I am unfamiliar with this one. Is there any other amps that are similar to this one i can scavenge some posts or diagrams to get me started?

KTA1504 and equivalent I dont have in stock. Ive seen them replaced in the power section with MMBTA56 but not sure if these would work in the audio section.

I have a couple of Jantzen Alumen Z-Caps for sale, purchased for a crossover upgrade that I ended up not doing.

They are previously used, but in good shape and test fine.

Asking $60 USD for both + shipping. I'm in Canada, should be about $15 USD for North America, or about $20 elsewhere.

Edit: SOLD!

Interested to buy two of this. Thank you very much!


Bogdan

OK, go easy on me please... need advice before I do something stupid...

Looking to add a 60 second delay the simple way (I know there are many timer circuits, but this seems like a slap in and forget for cheap)

SQUARE D 9050JCK13V20

Pros
Heavy Duty contacts - Octal base - DPDT - 120VAC Coil - timer dial range .6 to 60 seconds

See attached - 120VAC on Pin 2-7 activates 60 second relay - Left / Right channel outs to pins 1 / 8, ground on 4 / 5, final Preamp outs on pin 3 / 6.

Can this be as simple as this for less that $15 (Used)?
Since 120VAC, dangerous? Better sticking with lesser voltages?

Hi. Just got a Eurodesk Behringer SX2442FX mixer to repair. Came in the shop the other day. It has nothing coming out of the "main out" audio jacks. What could be the problem? OP amps? No history provided unfortunately. Everything else works, its just the output.

Hi Guys,
I have a Jukebox with multi hi-fi speakers wired internally, has anyone ever or knows a way to connect the jukebox to my sound bar or my Laney Bluetooth speaker?
Many Thanks

Someone can tell me if there's any mistakes on this schematic? I know on the 6v6 pin 5 and 4 are inverted and C13 is .015uf on the original schematic but i made this modification on the preamp and the sound is so bad. Regards.

I just made some handy tools today and thought I'd share, I would imagine others here have knocked up their own tools specifically for audio work and if you wanted to share in this thread, I'm all for it.

What I made were hand tools for Potentiometer / rotary selector nuts. I often use deep sockets, or longnose pliers, but neither are especially easy to use for this job - pliers can slip, and with a deep socket the nut tends to disappear up the hole especialy when trying to reinstall it.

So I cranked up Fusion 360 and designed a driver specifically for the task, scaled for 11mm and 12mm, "hit print" and voila.

They work a treat for the job. As the deep recess is enough for the shaft (it's 9mm diameter) but not the nut, it's easy to reinstall.

One thing which occured to me after, space for a small magnet (to the side of the recess) would be great for retrieving the nut and washer. I might give that a go in revision 2. Another idea is a hex nut up top, for those times "additional encouragement" is needed, but I don't know just how much one of these will take before it breaks (only one way to find out, I guess) and at that point it's probably time for the big guns anyway.

If anyone wants the .stl files to print their own (for personal use only, please) drop me a PM. One I printed in PETG, the other PLA, with 1.6mm walls (the shaft of the tool is essentially solid aside from the recess). They seem sturdy enough.

Are these genuine bc546b transistor? The logo is of fairchild but i'm not sure. I don't have beta tester so i'm asking forum members if anyone can identify them.
Regards.

My sub rattles - badly. It's not the driver. I don't think it's the cabinet. Could it be the ports?

If I block one port the vibration is reduced by 80%.

If I block both ports the vibration is reduced by 90%.

If I remove both ports and turn the cabinet on its side ( so the holes are sealed by the carpeted floor) the rattling vanishes.

My ports are similar to these but with a small flare on the internal end.

I'm stumped.

I am building a new home, and will have a dedicated media room approximately, 22' L x 18' W x 9' H.

I have a pair of Theil Smartsub 1.12 drivers I bought at their liquidation auction, and was considering building new enclosures, but was wondering if anyone has had any luck with IB's. I am going to build an interior wall 2 feet from the basement wall for my screen, and was thinking this might be a good area to put the subs.


The space would be approximately 2'dx18'wx9'h.

Any ideas, comments, or reference material would be appreciated.

I have been searching for the name of this class A output topology and its designer for months now, but it escapes me:



Can someone help and put me out of my misery?

Hi,

I study the schmatics of the Nakamichi RM-300 Remote control, which is the original wired RC for the Nakamichi 1000ZXL.

Its schematics is provided in page 99 of the 1000ZXL Service Manual, and is herebelow:
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On this schematics, it appears that the pins 2 and 4 of the RAMM DIN connector (see upper right) carry information coming from the 1000ZXL to the Integrated circuit IC-001 (this info should be used to display the counter value on the RC counter).

I try to know how this information is formatted from the tapedeck ? is there a modern integrated circuit that could read this information ?

To date, nobody knows...

Thank you

Hi guys,

What type of insulation material do people use between a PCB and a metal chassis.
I know stand offs are used as a spacer underneath offering protection, but what can be used on top or below, as I often see in commercial products a type of hard card.
The reason for asking is my current project fits very tightly into its chassis.
Thanks in advance.

IMO. a K-tweeter for a little cone can work well with a shallow tapered chamber and thus something like a miniature K15 vs a klam arrangement. (One can certainly try both and I've not worked with the mini-klam enough to pass judgement)

A strong on-axis rise is highly desirable for acceptable result. The 3" LaVoce
I picked has about the strongest seen for that size and little money. Its a very well made driver too.

Anyhow, one might make a fullrange "flooder" of sorts with driver facing straight up and lens set on top. My cardboard cabinet has a couple feet of expansion, then choked at terminus, "balloons" from pressure. A more proper rear load and construction should help.

With an oval slot lens, sound was strident - with this happenstance K-lens, things are quite holographic with sounds such as fireplace "sparks" alive pretty far off axis.

It could be used with small back chamber as a tweeter.

LaVoce FSF030.70 3" Ferrite Full-Range Woofer 8 Ohm

I'm using the Tubelab SE schematic and checkout procedure from the Tubelab website and can't find R7?

Has it been replaced with R6 on the TSE-II board?

Thanks!

Hi

trying my luck here (after I was not successful in the "Digital source" section): I am looking for a rubber belt for my Mark Levinson 39 CD Player. That belt is driving the CD drawer. Dimensions: 35mm circumference, 1.5mm thick, round.
ML wants $58 for the original (red) belt.
Any feedback is much appreciated.

Out of the archives I found an original Muffsy Phono Board PP-3 and related documentation. $10, includes shipping to CUS only.
PM if interested. Thanks.

11/08/20. SOLD

Hi all.

I've been bumping around looking at various amp and speaker DIY sites for a while now so I figured I should sign in. I might be the worse type of noob; I trained as a EE, teach high school science, and ran a FIRST robotics team for many years. In other words I have just enough knowledge to nod along at all the right places but none of the experience to actually move into the expert category!

My short term goal is to build what is more or less a more complicated computer speaker. Mono speaker with a tube amp built in to run from either the headphone jack of a phone or computer or, as a second step probably, from a bluetooth connection. I'm not much of an audiophile - the project journey is the most interesting part although getting something to use while working on other things will be a nice side benefit.

Expect to be plagued with questions about a very fringe use of tubes!

Hi All, my name Is Mauro, long time in service for automatic test equipment and HiFi fan
In the last years i became fool about tweaking what i have, that's why i'm nere
Thanks for being on the web

Hello All,

I have a question about power supplies for our old-time favorite Class AB amplifiers.

I have lately measured the THD+N of several amplifiers. Many, most if not all have with Full Wave diode bridge plus Capacitors even including inductors the power supply noise, you know the 50 or 60 Hz series, 60Hz, 120Hz, 180Hz and on up, of diodes turning on and off spikes dominate the THD+N figure. The power supply spikes are higher dB’s than the 3rd, 4th and 5th harmonics sometimes.

Switch mode power supplies in Class D amplifiers are quieter than the previous generation.

The question: Has anyone or does anyone use switch mode power supplies in old school Class AB amplifiers?

Just for grins here is a sample of a well behaved Full Wave diode bridge power supply in a NAD amplifier. I replaced with new the protection relay and all of the PS capacitors. Plus a not so well behaved example.

Thanks DT

I've gotten interested in using the JFET-NPN hybrid Darlington connection shown in Figure 1 below. While a standard Darlington has an emitter follower which drives another emitter follower, this circuit has a JFET source follower which drives an emitter follower.

I think I'd like to try the "J105" device in this circuit, and as luck would have it, I bought 100 of them back in August of 2014. I keep a little snip of the shipping bag in my parts drawer, to remind me where and when I bought these units. The J105s came from DigiKey: Figure 2.

So I chose twelve J105 units at random, and put them on the curve tracer. I plotted IDS (vertical axis) against VGS (horizontal axis) with VDS held constant at 10 volts. The slope of this curve is d(Ids)/d(Vgs) which has a special name in circuit design: transconductance. Often written "gm".

The measured data is shown in Figure 3. There's quite a spread in the data!

Simplistic mathematical models of JFET behavior suggest that IDS = Param1 * (VGS - Param2)**2 where Param1 is a gain factor related to the JFET's channel width and length, and Param2 is the "Pinchoff Voltage". "**2" means raised to the power 2, i.e, squared. The data in Figure 3 suggests that the spread of Pinchoff Voltage for these twelve J105s, is about 700 millivolts.

To see this, draw a horizontal line at IDS= 50 milliamps. It intersects the leftmost J105 curve at VGS= -5.7 volts, and it intersects the rightmost J105 curve at VGS= -5.0 volts. A spread of 0.7 volts (!).

If a (very small) sample of just 12 parts, gives a spread of 700 millivolts, I imagine that a larger sample will give a much bigger spread. I hope to measure many more J105s in the coming days, and find the very leftmost curve, and the very rightmost curve. These represent the extremes of the sample and, I hope, they may approximate the extremes of the population of all J105s ever built and sold.

If by some miracle I can find SPICE model parameters which fit these two extreme transistors, then I can simulate circuits using the "best" J105 ever built and also the "worst" J105 ever built. If my circuit design works acceptably with both extremes of J105 then I can feel confident it will probably work acceptably with average J105s that are not so extreme. That's the hope.

Fairchild's datasheet is also attached.

_

Anyone have pics of this area ?

Hi I'm new here, I'm from Italy 🙂, sorry for my bad english.

I have a PG MS-275, unfortunately it have distorted output sound from the two channel.
Two of the four red led are lightly on and the other two are working fine.
I change the caps and check all the transistor but I can't find any problem, also my external power supply is good.
I try also with another pair of woofer but the problem is still there.

The distorted sound occurs more when the music have bass so I think it's something relate with power but I don't know what it can be.

You have any advice?

Thank you!😀

Despite my extensive google'ing (Newark, Mouser, DigiKey, etc), I can't seem to locate a source for paired 3.5mm mono panel mount jacks such as:



The only ones I've found appear to be intended for direct PC board mounting. I need either solder lugs or socketed like this one:



This would be used for the 12v trigger(s) in a (hopefully) simple ICEpower'ed amp I'll be assembling.

Suggestions would be much appreciated.

SOLVED, no more needed

Hello I need a pair of scan speak 12M/4631 for an ekta grande kit.
If you have any available, please, let me know.
Thanks.