Quantcast
Channel: diyAudio
Viewing all 96202 articles
Browse latest View live

Help with my Open-baffle set-up

$
0
0
Hello all !

I need some advice regarding 2 way open-baffle configuration . I have one 8 inch wide-range and 2 x 15 inch per side . The wide-range is driven by a AB class amplifier with no volume control and the woofers by a class D amplifier also without volume knob . I have a DAC with 2 RCA inputs and control volume , the signal is send by an Y cable to the amplifiers . The PC is the source .

The wide range sounds good as always , i have it for quite some time an d i have listening only this driver , sounds great . The woofers are the problem , i have a very bad , weak and muffled sound . The class D amplifier is set to LF and Stereo . Even at max volume ( almost clipping ) the sound is weak and muffled . Any thoughts ? Is some software tricks ?

I have NO experience with Pro drivers . Or amplifiers for that matter so bear with me .

Thanks

FS: Some Ian Canada PCBs

$
0
0
I sell the following components, all unused, except I2S to PCM and Fifopi. I bought them as spare parts. Fifopi I just bought it from Pistollero, it's not what I need.

Cost shipping from Spain by the buyer.

A) FifoPi: € 80
B) IsolatorPi + Dop Decoder: € 60
C) Fifo II + DualXO: € 110
D) SPDIF FIFO: € 60.
E) I2StoPCM € 50.

B + C + D € 200

Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.

FS: Chip Dac Philips Tda1541A R2 and S1 Single Crown

$
0
0
Great sound with these dacs chips.

R2 40€
S1 Single Crown 90 €

S1+R2 110€

shipping costs from Spain by the buyer.

Click the image to open in full size.

My go at the Martello & FR88EX

$
0
0
Earlier this year I joined this forum with the intent of trying to learn how to build my first set of speakers. My first two posts were I guess out of place and I should have been more contrite.
After reading about & looking at all of the near field full range speakers here I decided that I would try and attempt to build a set of Montellos. I would like to thanks Big Gun for the inspiration & all the other posts that shared their experience in this little gem of a speaker. building this has been a journey, lot if fun and has tested my skills as a hobbyist wood worker.
So on with the show:
First pic starting out, having cut the pieces from the 1/2" baltic birch I arranged them so I could keep track of the assembly.
Second & third pick, I decided that I was going to attached a veneer so I thick sliced some 1/4 sawn white & red oak. Two of the pieces turned out to have this wonderful grain pattern that became the front baffle for the speakers, the other pieces were from different pieces of firewood. Pieces are about 1/4" thick & surface planed & sanded to 250 grit, 80 at first then 180 to the final 250.
Pic four, All the pieces are cut & ready for final assembly. I sourced out 1/2" felt from McMaster Carr. They sell a"soft" moving felt that is porous to blow through. Hopefully this is the correct choice.
Pic five, Assembly, I secured the felt prior to cut with double sided tape and test fitted each piece speaker trimming felt as I went for a snug fit. Each piece was set to dry for a day.
Pic six, to set off the top & bottom from the sides I used cherry. I messed up cutting the ports so I remade them using the same wood as the front baffle and added a cherry splice to break up the grain not matching.
Pic seven, time for a snooze, Toonces kept coming down to check on the progress so often that when he did not show up one time I had to go looking. Guess he bit tired
Pics eight nine & ten, left front, full set up & right front.
The right front shows a rookie mistake, I set the flush trim bit too high, clipped the driver baflle, had a few choice words with self and oops did it again at the splice. Lesson learned. My wife said she will just smile every time she looks at them. :)
These will eventually go on her desk/ home office as she is working at home while the battle of Covid19 rages on.

I am thinking about making some for this location using 3/4" speaker spikes. Would they sound the same as these???

Oh by the way these sound AWESOME. I am using my college Yamaha R300 to power these w/ a NAD cd player and will use a Wiistar digital,optical coax to analog DAC to watch the tv.

My main comparison for audio are a pair of Polk M7's. These Montellos are clearer in the high range and almost match the mid if not very close. The bass is not as mature as the Polks but is full and punchy.

I listened to Copland's Rodeo Suite and heard instruments you could not hear as clear on the M7's. If you know the piece of music, there is a section in the second & third movement where a single triangle is used. In the Montellos you not only hear the sound but the strike, in the M7's you hear the sound but the strike is not as pronounced. Staging is remarkable as well.
I wonder how much more or less would the sound be if I build a pair with the spikes, Hmm?

Well I'm going to say thanks to the designer of the Montello

For those who want to know the finish on the veneer, I used boiled linseed oil on the cherry. On the oak I started with a trans tint called golden oak in denatured alcohol, 24 hour dry time and then boiled linseed oil over the whole speaker again, cherry & oak. Burnishing as the linseed oil dried. every few hours for an hour or two. No finishing varnish or shellac as I want the oil to mature into it's own patina. You could try some amber shellac on a trial piece to bring out the color. I am satisfied with the vintage look of the box.

ENJOY & BE SAFE

Testing capacitor in circuit

$
0
0
Rookie question from a non-audio technician-

A 36pF mica capacitor on one channel has ~1 Vdc with DMM leads across the capacitor leads. The other channel, same component shows zero Vdc.

The capacitor that measures 1 Vdc is bad?

I ordered new mica caps, (expensive compared to other components), but won't be here for a few days and I'm trying to learn.

true balanced, fake balanced and other balanced amps

$
0
0
I ran some tests on my amps recently. I was surprised to find one amp was fake balanced the other (not surprised) was an honest xlr only single ended amp and the other was something else. I have a question about that last one.

The test was two things:
1) with amps off checking continuity between pins on the xlr inputs. If any of the two pins beep (usually 1 and 3) there's a pin tied to ground (1)… (probably)
2) I made a thru board XLR in and out and had pin 1 (ground) connected thru at all times. Then I was able to connect pin 2 in to pin 2 out or 3 only or both and read the output on a 4" driver.

the amps and results:

Adcom 555se = fake balanced. pin 3 connected I got nothing. pin 2 only and I got full signal. Both 2 and 3 connected thru same full signal.

Yamaha P2050 = honest single ended XLR only amp. Same results as the Adcom.

Cerwin Vega CW-1800 = Strange. With pin 3 only connected there was nothing. With pin 2 only connected I got 76.8 db out of the driver. With both 2 and 3 pins connected thru I got 82.8 db out of the driver. On this amp I connected a XLR cable up to the input (amp off) to do test 1 and put the leads in the other end of the cable to test continuity. This amp has those XLR / TRS combo jacks and I didn't want to miss. It beeped when connecting pins 1 and 3. hmm?

This is kind of a two part post what have you seen? Any other weird results from a "balanced" amp? What is true balanced supposed to do in test 2? And what could be going on with the CV-1800?

Attached Images
File Type: jpg ADCOM 555SE.jpg (544.7 KB)
File Type: jpg P2050.jpg (624.2 KB)
File Type: jpg CV-1800.jpg (623.6 KB)

Paging Horns & PA Driver

$
0
0
Hi

Last election I acquired two bad shaped paging horns, since the owner didn't bother asking them back. You know those round 25 or 30 Cm diameter cones, You put on the car roof.
Since they were deformed / oxidated, I took them apart and repaired / painted them and they work but I found some oxidation inside the drivers. The coils are 16 ohm 35W and were wired in parallel.

I am planning to built an amplifier, since I have two TDA7275 50W amplifier chips around, salvaged from my old Grundig Head unit. It will include a mic preamp bass & treble controls and will mix with an USB / SD card reader module or aux input. A few op-amps.

When I look at specs for drivers, what comes to my attention is the frequency response .. most of them go up to 7500-8000 Hz.
Is there anything I can do in order to step up the response a litle bit ?

Can I use ordinary PA compression drivers with them, since the originals are the same screw on type ? For example a Selenium D220 TI.

The voice coils sizes look identical to me, but the seleniums are made of titan instead of phenol.

I am looking at mixer schematics right now, since I own several ones but if anyone could post a circuit based on a commercial unit that would be great.

Thank You

New NXL500 R5 dual mono with center channel build

$
0
0
Hi all. It starts!!

L and R power amp dual mono based on the 500. And added a center channel with a NXV201PS to hopefully get a better center channel than the denon AVR4520.

The case is quite large but it's still a tight fit.
Center channel is trigger activated only from the AVR and has LED on front panel to show it's on. LR dual mono main amp has push button on front with LED and also trigger option from the AVR as well.
Attachment 841119

Attached Images
File Type: jpg IMG_3339[1].jpg (997.6 KB)

Design flaw Lynx L22 sound card

$
0
0
Using the DAC outputs of a L22 in single ended (SE) mode* means trouble. Although it performs reasonably well above 1kHz, below say 100Hz, the distortion increases drastically. At 16.35Hz THD rises from -117.6dB (balanced mode) to -75.9dB (SE mode). That's 100 times more! See fig1. vs fig.2 (Another measurement reveals an increase of 'only' 30 times).
Also the frequency response is affected in SE mode. At 10Hz it drops to about -3dB, while in balanced mode only -0.2dB. See fig. 3 (balanced) vs fig.4 (SE).
The reason for this flaw appears to be a X5R ceramic capacitor in the signal path. See fig. 5, C5. The distortion is not only a result of a wrong type of dielectric but also the value of only 100nF is way too low. As a result, the output current of op-amp X3 rises far beyond its limit at low frequencies, over 25mA. This also introduces more distortion, probably the main cause.

And the remedy? Simply short this evil capacitor, in both channels of course, see fig. 6 where to find them**. Initially I was afraid of a larger off-set voltage at the outputs. But that wasn't the case. It was even lower after shortening these caps.

BTW, I also experimented with other op-amps: A LM4562 instead of the original OP275's, but THD figures were about the same. Maybe OPA1656 will do better.

Cheers,
E.

*XLR pin3 shorted to ground (pin1)

** The two blue wires were just for experimenting with larger caps connected via the 25 pins delta connector from the outside world.

Comment from Bob Bauman at Lynx Studio:
"I will not confirm that your schematic of the line driver is correct because that is proprietary information. However I will say that there was one 100nF cap that was replaced with a zero ohm resistor in later renditions of the line driver."

Attached Images
File Type: jpg L22-THD1A.jpg (108.3 KB)
File Type: jpg L22-THD2.jpg (101.3 KB)
File Type: jpg L22-F1.jpg (99.2 KB)
File Type: jpg L22-F2.jpg (104.2 KB)
File Type: jpg L22 Line Driver-2.jpg (76.0 KB)
File Type: jpg L22-mod.JPG (417.9 KB)

d&b audiotechnik Anyone knows which driver brand they use?

$
0
0
Hi,

I would like to know if any on you you know which component brand does d&b audiotechnik use in their systems, particularly:

-. the 12" neodymiun woofer in their J12 system; and
-. the 1.3" exit HF compression drivers with titanium diaphragm in their C3 system.

Sorry i post this here, but I know there are many users from europe in this forum.

thank you in advance.

Is this a new topology?

$
0
0
Click the image to open in full size.


By giving a hand to zintolo with his GU50 projects I came upon this circuit. The bootstrapped pentodes provide a gain of 75db ,yielding 40 ohms plate to plate output impedance for 6k load by plate to cathode feedback. The input inverter comes from Audio Research D70 , It can function without by parafeed mode but oscillates on saturation. Using Ayumi models the amp exhibits 80w with 0.03% Dtot.

Attached Images
File Type: jpg GU50 SCAHET.JPG (214.0 KB)

WTB: Novar sockets (PCB mount) for 6LR8 tubes or equivalent

$
0
0
As in subject title. Would like at least 1 pair. PCB mount only; I already have chassis mount type.

Best,
Anand.

Semi-permanent DML exciter adhesive

$
0
0
Hello! New DML / exciter experimenter here. Been lurking for a bit.

Anybody have experience with semi-permanent adhering of exciters to their panels (XPS, EPS, etc)? I would like to experiment with exciter locations before permanently adhering the exciter to the panel, and I want a more permanent (and accurate experiment) than sliding the panel around with my hand.

Any thoughts on type of adhesives that can be easily removed but will not dampen the force from the exciter? Hot glue? Contact cement?

OTK 6J1 biasing problems

$
0
0
Hi folks,

This is Vincent from Hong Kong and it is my first post in DIY Audio. Nice meeting you guys here.

Recently I'm working on adjusting OTK 6J1 biasing voltage. The 6J1 is triode connected and self-biased. I found that the cathode voltage is not stable with certain combination of anode resistors and cathode resistors. By "unstable" I meant the voltage is varying up and down.

In addition, as the 6J1 is triode connected, the anode current should be the same as cathode current, right? However if Ia-Ik, the result is not always zero. What did I do wrong? Please see the schematic and data below. Thanks guys!

Attached Images
File Type: jpg data.jpg (104.4 KB)
File Type: jpg 6J1.jpg (274.4 KB)
File Type: jpg 6J1 Bias.jpg (74.8 KB)

FSD 5000D dc on speaker terminal

$
0
0
I have 112vdc on the speaker terminal. When I use my scope is plays a clean signal but if I hook a speaker up the cone shoots out due to the dc I'm assuming. Does it have anything to do with the pots in the pic?

Attached Images
File Type: jpg 20200505_093815.jpg (1.02 MB)
File Type: jpg 20200505_093847.jpg (851.8 KB)

ACME 300B + TU-8600

Inserting software high-pass and gain between sound card and application software

$
0
0
Hi all,

There is a field biologist on this forum who tries to monitor the sounds of migrating birds using microphone capsules, sound cards and special software on a Raspberry Pi, see https://www.diyaudio.com/forums/ever...d-project.html

He needs to somehow increase gain and insert a high-pass filter between the microphone and the special bird recognition software. I can give him advice on how to do that in the analogue domain between microphone and sound card, but measurements show that a software solution between sound card and bird recognition software would result in almost the same noise floor.

Does anyone know how to insert a real-time software high-pass filter and gain stage in between the sound card and the bird recognition software? A second-order IIR filter at 1 kHz would be sufficient.

Best regards,
Marcel

Free (Australia) - Amp modules and DC power packs

$
0
0
I will cover postage in Australia only and is for all items as a bulk package. If there are items you don't need, just pass onto someone else.

* Dayton DTA-2 amp module which uses the TA2024 like the old Sonic Impact of yesterday. Needs a 12VDC (max) 2A power supply and is wired as a power amp but the volume and switch is included. Just swap over at the connector. https://www.daytonaudio.com/images/r...al-revised.pdf

* TPA3116D2 amp module which needs a 12VDC 2A to 24VDC 4A power supply.

* TPA3116D2 amp module with volume control and 3.5mm input socket. Same power requirements as above and this one has a bit of hiss. I turned the volume to max and adjust the volume at the source.

* 24VDC 1A new linear unregulated power supply (33.4VDC no load). Not suitable for the above amps and needs regulation for most circuits. 2.1x5x11 + pin.

* 12VDC 300mA new linear unregulated power supply (17.9VDC no load). Not suitable for the above amps and needs regulation for most circuits. 2.1x5x11 + pin.

Attached Images
File Type: jpg RZ_DTA2.jpg (176.6 KB)
File Type: jpg RZ_3116.jpg (209.5 KB)
File Type: jpg RZ_3116V.jpg (180.6 KB)
File Type: jpg RZ_DCpower.jpg (197.2 KB)

Free (Australia): TDA1543, TDA1545, K170

$
0
0
During my clean out I found these which may be of some use to someone. I'll give it a week before I throw them out. I'll cover postage in Australia only.

TDA1543 DAC new
TDA1543A DAC used in a NOS DAC
TDA1545A DAC new
4 x K170 used (was in a B1 buffer) and were originally matched but can't say they are now

Attached Images
File Type: jpg RZ_DAC_TDA.jpg (118.4 KB)
File Type: jpg RZ_K170.jpg (94.9 KB)

Help with DIY Hivi center speakers

$
0
0
Hi. This is my first post here and looking for advise on how to DIY speakers. My current setup are three KEF Q300 for the front and center, SVS PC12 sub . The surround are taken care by wharfadale. I just bought a set of ready made DIY speakers from China with Hivi drivers. Below are the pictures of the speakers and its called S8.
Click the image to open in full size.

It’s a 3 way speakers with Hivi RT1C-A Isodynamic Tweeter, DMB-A Dome Midrange, and F8N woofers.

I use it mainly for 50/50 movies and music.
I’m looking to build a center with the same hivi drivers and crossover with the same cabinet dimension but with the tweeter and mid that is aligned vertically and a single F8N. Below is a rough design layout.
Click the image to open in full size.
I believe this speakers should have the same crossover as the Hivi diy3.1 as the drivers used are very similar so I am going to use the diy3.1 crossover for the center speaker. Below is stock crossover for the diy3.1
Click the image to open in full size.
There is also a perfectionist mod crossover as below
Click the image to open in full size.
I am not sure if this design would work well as a center speakers. Another options is to go for a W(TM)W design like most center speakers but instead of a single F8N, I could go for two F6N woofers. Because this is my first time building speakers and I have very little knowledge on crossover, I would really appreciate if anyone can tell me if I can use the same crossover when I use two F6N drivers? Or do I need a new crossover for the woofers? How is the wiring for the two woofers?
Viewing all 96202 articles
Browse latest View live