Hello,

I would like to built this model:
Ellipticor-3
but the price of the speaker...

What I like on this project is very well documented. Just coy past and you have something and in term of design it's totally WAF.
I don't want to make a new project from scratch, if you have some idea.

Regards

The power supply drivers are marked

M6
L6

And some other transistors marked G1

Does anyone know what the part number is for these ?

Hi, I purchase some years ago the uTracer, a tube tester kit, from dos4ever.com, this circuit is very useful but I'd like to add a voltmeter an amperometer at the heater circuit.
There's someone know this Kit, and if yes, has does this improvement add a voltmeter?
Thanks

Sergio.

So, I'm having a problem with the definition of Vas.

I've read somewhere that Vas is the volume of air that, when compressed down to 1 m³, exerts the same force as the speaker suspension.

So I'd imagine the speaker suspension is also pushing it back too due to the displacement (the same one that compressed the air), and the two forces are equal, both pushing it back.

The problem with that is that, considering isothermal compression at least, the initial volume doesn't matter: there are only two volumes where the suspension and the force caused by pressure difference will be equal, one being the initial volume itself (as both will be zero) and the other one being a fixed value. So Vas could be literally anything, the final volume would be the same, and it would only be 1 m³ for some combinations of suspension stiffness and cone area.

I considered adiabatic compression too (which makes much more physical sense), and then the initial volume does matter and it's possible to find a "Vas", but the values I found were nonsensical.

But then I went for another interpretation: The volume of a sealed box where the air would behave as spring of constant K similar to that of the speaker suspension.

Considering adiabatic compression and expansion, and that the pressure in the outside of the cone is constant (a good approximation in most cases, as the variation of pressure inside is much greater than the variation outside), the force caused by the pressure difference is:

F = P_atm·A·{1-[V/(V±A·x)]^1.4}

Where x is the displacement, V the volume, A the frontal area of the cone, P_atm the atmospheric pressure and 1.4 the adiabatic index of air. Using SI units, the force will be in newtons. The symbol ± was used because it will depend if it's an expansion or compression.

Doing a Taylor expansion of the term [V/(V-A·x)]^1.4 near x=0, we can reduce everything to a spring-like force of:

F = -1.4·P_atm·A²·x/V

Where the spring constant would be 1.4·P_atm·A²/V

That approximation is very good for small x and large volumes, which is mostly the case for speakers, as the volume they displace is very small compared to the enclosure volume.

That interpretation gives more reasonable Vas results. For example, a 20 cm (effective cone diameter) speaker with a 400 N/m spring constant suspension would have a Vas of 0.35 m³ or 350 liters (considering P_atm = 101325 Pa). This is a speaker that would lower 25 mm if you put a 1 kg weight over it.

Is that the correct meaning of Vas?

I have 3 video sources feeding to my main audio system, the cable box, Blu Ray play and a 4K firestick. The TV is a cheapie Spectre 40" with no digital sound output. I want to feed the video sourced audio to my analogue sound system, stereo only. Anyone have information on the quality of the DAC in this decoder?
4K HDMI 5.1 Audio Decoder Bluetooth 5.0 Lossless Player USB Sound Card Version | eBay


I do not need a home theater 5.1 channel decoder. I want the HDMI switching and DAC. Currently, I have to use 3 pieces for that function.
1. A HDMI 3-in/1-out switch.
2. A HDMI input to I2S output converter
3. A ES9038Q2M DAC
It works ok, but looks messy.

Greetings.
I am shopping for replacement parts for this amplifier, I have Mr. Babin's repair tutorial, and am an experienced tech.
The first question I have is about the two large filter caps in said amp.
One is bulged and the other is not.
I intend to replace them both, along with a lot of other parts in here.
The max height with bottom cover installed is ~35mm.
Is this a suitable replacement?
Thanks for the help, and I will cover this repair completely in this thread for the next guy/gal to use...😀

paul

Hello,

I'm fairly new to speaker amplifiers but I understand the different classes (i.e.: Class A, Class AB, Class D, etc), but how would I identify the class of an amplifier, for instance if I was buying an amplifier online and the class was not mentioned, how could I know the class of the amp?

Thank you.

Has anyone ever built a concertina phase splitter and have the signal be perfectly split but they differed in amplitude?

Hi .

Where can found R-core Transformer in internet?
I want about 1.2KVA

thanks a Lot..
🙂

Hi,
me and my friends are trying to construct a horn speaker, with a bandwidth of 90-500 Hz. We chose to base our design on the B&C 12FW76 driver. We were surprised, that our calculations gave a compression ratio of about 1:4.88.


I used the following equations to calculate the throat area:


efficiency = Fs / (Fch * Qes)
St = efficiency * Re * density_of_air * c * Sd^2 / ((1 - efficiency) * Bl^2)


where:
St := throat area
Fch := upper cutoff frequency (500 Hz)
The other parameters are the Thiele-Small-Parameters of the driver and physical constants.



Are my equations wrong or do you think this is a reasonable compression ratio?
Can a high compression ratio damage the driver?



Thanks and have a nice day everyone.

Hi Everyone

I found and joined the other day, I’ve just upgraded the plinth on my Rega P3 and found some useful information on here while I was researching various bits of info, great forum and loads of good information.

I’ve literally just finished making a new plinth out of a carbon fibre board, which has a foam core, similar construction to the high end Rega decks, however mines much thinner at only 9mm thick.

Wanted to sell😱ne pair Fostex FE 167e

Two hardly used, almost like new in bass reflex test box and are spares for the other two that are in a closed box but are used with low power

Due to living in New Zealand it would be best to ship only the drivers.

Needing to downsize, moving to smaller place, too many speakers. Originally pruchased to make a metronome but it did not agree with our living space.

Have original boxes for two, will need to find some suitable boxes for the other two.

Offers wanted.

edit: No longer available.

Apologies if this has been covered, did not find it in search.

What is the proper way to add LC filtering to a voltage doubler? I have attached a sketch to show what I mean.

For the case where EITHER the Vdc or 2Vdc legs of the doubler will be used (shown as switch selectable), is (1) or (2) the correct method? Or is there another preferred option?

For the case where BOTH the Vdc and 2Vdc legs will be used (current draw simultaneous), is (1) or (2) the correct method? Or is there another preferred option?

TIA

Does anyone know of a setup for the UPV that makes testing compression amplifiers and graphing the ballistics of the attack and decay/recovery times possible?

When I was researching the UPV for purchase last month, I ran across some article about testing compression amplifiers. Silly me, I did not download or save the article and now I can't find it. The article showed some screen shots and talked about using the UPV to test the response times of compression amplifiers. Where is that article?

If anyone knows of a setup file, that would be terrific.

Hi,
I have a Rotel RC 1080 preamp going into a Quad 606 preamp

Here is the Rotel RC-1090





Quad 606 power amp



Quad 606 Power Amplifier Specification
Power Output: 140 watts per channel (8 ohms)
Distortion: < 0.01%
Input Sensitivity: 500mV
Input Impedence: 20Kohm
Crosstalk: -100db (100hz), -85db (1 khz) and -65db (10khz)
Hum and Noise: 105db
Voltage Rating : 220-200V AC (110-120V via simple power board modification)
Dimensions (WxHxD): 321 x 140 x238 (mm)
Weight: 12kg

The preamp out is 1v and the power amp input is 500mv

What level attenuator would I need to buy to match the preamp to the power amp
-10db or -20db or some other figure?

Thanks

Lee

Musical Fidelity X-Cite

Hi everyone.

I’m looking for a pair of musical fidelity x cite blocks to stack my x units, but their as rare as hens teeth 😆. I was wondering if anyone had sizes, dimensions, for these, I could try and make something that works myself.

Thanks for all your help.

I want to improve the speaker setup for a friend of mine who is just getting into hifi, but his room is far from optimal and I need your help. It's L-shaped and has two windows.
Dimensions of the part of the L, in which I can move the speakers arround are 2.5x3x4m (HxWxD) and the dimensions of the other L-part are 2.5x2.6x4.9 (HxWxD). The two widths come together to form the long part of the "L" if that makes sense. The two windows are both on that long wall -one sadly on the 3m part of the wall behind where the speakers are now.
UnfortunatelyI forgot to take some pictures of the room when I was there, but I made a quick sketch of the room in a homedesign software I used for my own house a few years ago -I marked all possible speaker positions with X's. Hopefully that's enough. I'm thinking about placing the speakers infront of the large bookshelf on the 4m wall.



Please help me. I would greatly appreciate it🙂

I have to pare down my stable of amps.

This J2 is factory stock with two pairs of SemiSouth JFETs ( 1 pair per channel).
There is a minor nick on the top of each heatsink, but hardly noticeable. Also some scratches on the bottom, (not from me,) I am not the original owner.
They list for $4000 new, so a good time to buy the J2 and save a few bucks. It is very smooth sounding, very detailed and produces 25 watts into 8 ohms in a single ended amp with both balanced and single inputs.

I will sell this one for $2100 shipped FedEx in the lower 48 states plus PayPal fees. Sold!

Rush

Hi, I'm building a 3-way speaker system. Currently in the process of trial and error about the polarity. Actually, the crossover networks I used were taken from commercial speakers. There's a problem that I'm going to discuss for the following.

The original marks of polarity on crossover were as follows:

Tweeter: -
Midrange: +
Woofer: +

After having wired as original, I felt the sound didn't satisfy me, so I tried to swap the polarity of drivers in different ways. I found the sound of the high region right to my ears when tweeter and midrange were wired with the same polarity. And the low range right to my ears when woofer and midrange were in opposite polarity. And another result I found was the tweeter must be wired at + polarity, don't know the reasons why it's different from wiring at - too.

In brief, the configuration that makes the sound best to my ears was:

Tweeter: +
Midrange: +
Woofer: -

The question is I'm concerned about wiring woofer in - (negative) polarity as I have never seen any commercial speakers wire their woofer as such before. So, could anyone please suggest me the disadvantage of this wiring configuration? I'm afraid the problems may come later, such as the voice coil former hit with the magnet due to reversing its moving direction or anything else. Please suggest to me. Thank you in advance.

I’m just curious as to what you guys think caused these zobel networks to fail like they did.

I’m thinking a short in the speaker wires. All 4 channels have been zapped.

David

I'm very interested in optimisation of a Windows based HTPC. I have an XPC with the following specifications.

Windows 7 32-bit.
Intel i5
4Gb RAM
AMD HD6450
128 Gb SSD
1Tb HD

This system is designed for low noise and low power consumption. It occurs to me that the standard configuration of Windows is unsuitable for the unit's purpose. Features such as indexing, pre-fetch, super-fetch are redundant in this set-up. The only third-party software used is Firefox and Kodi. Even the Windows swap-file is a waste of resources.

I have placed the Firefox cache on a Ram-disk to aid replaying parts of streams.

Does anybody have any ideas as to any further tweaks?

Hi,

I would like to build a Linear P.S. able to deliver approximately 10A.

The output voltage should be 12V (fixed, there is no need to have a variable output voltage): this is to replace the switching P.S. of a NAS.

I am looking for a shematics of a reliable and simple P.S.: maybe a few of you have already built a similar P.S. ?

Thank you for your help,
Michel

Hi ! i have a pairs of chimera labs ace prototype by Dennis Boyle which i really liked them , currently i have 6l6 power tube and the previous owner said that i can used el34 or kt66 for them but i never try them as i don't know how to bias them, i saw there a knob on the back of each with 5 position adjustment i got no idea what that was beside the volume control on the front , so if you have them please give me some info that will be awsome ! thank and have a great day

Here's some information that some of you may find interesting.

At Pass Labs we use Bergquist Silpads for thermally conductive
insulators on TO3P (Plastic packages) but not on the TO3
packages because they tend to shear and fail with the TO3.
This is not the case with the TO3P because of the smaller single
hole and the transistor's plastic insulation around the mounting
hole.

We've been happy with the Silicone pads in this application as
they are less messy and perform nearly as well as the
traditional Mica and thermal goo. As far as I can make out,
they have lower thermal impedance than claimed. However this
is assuming a certain degree of smoothness of the metal, which
is simply the flat surface of an anodized extrusion, and has a
somewhat polished look to the finish.

More recently with the First Watt product, the heat sink has
been bead blasted to make it more spiffy, and you'd think that
the slight dullness of the surface wouldn't make a difference.

In fact it made quite a bit of difference with the silicone pads -
apparently something like another 50% thermal resistance, and
I ended up using Mica and goo. The figures I get are 1.5 deg C
per watt with mica, and 2.1 with silicone. This is obtained by
running the devices at 20 watts and measuring the temperature
of the top of the case versus the heat sink right next to the
device.

If we take the ratings of the device itself, we see internally we
can expect .83 deg/watt, and so we see that Mica and goo
end up about 1/2 the total thermal resistance. If your surface
is not flat and polished, and/or you're pushing on the power
ratings of the device, consider good old messy mica and goop.

😎

I have an extra sheet of Kerafol 'Keratherm RED' 86/82 190mm squared .25mm thick
(7.48"sq x .01thick) imported from Rapid Electronics UK


Will cut/divide into one-third(1/3) sheets which will be enough for 16 (23mm x32mm) TO-247, TO-218 insulators 16 x (1.25" x .92") or cut to suit your needs.



$25.00 - 1/3 Sheet (2.50" x 7.48" +/-.01)
FREE Shipping Lower US 48 States ONLY - International Ship at your cost

Keratherm. 32mm x 26mm, which will fit TO-247, TO-3P, TO-218, and can be cut with scissors to fit TO-220 and smaller packages. One side is smoother than the other.
10 Kerafol "Keratherm® Red" premium insulators
Model: 86/82
Format: XXXX-028 (To suit TO-247, TO-3P and TO-218)

ONLY CONUS

Hi,
How are you?

Hopefully you would give your thoughts and opinion asap...as I am in A shop and they're closing soon.

Amp: Hertz HDP4

2 compo speakers that I need to chose from:

DLS Reference RZ6.2
Impedance: 4 ohm
Power Handling: 100W rms / 150 W max / 300 W peak power
Sensitivity (1W/1m): 85 dB
Frequency Response: 50 - 22,000 Hz

Morel Tempo 6.5
Impedance: 4 ohm
Power Handling: 120W rms
Max. Power Handling: 280W
Sensitivity (2.83V/1M): 90dB
Frequency Response: 40–22,000Hz

Thank you very very much

Hi, all.
I stumbled upon a custom pair of Yamaha HS5 whose woofers were "painted" by the previous owner with gold foil. He said that since its very thin it doesn't affect any frequencies.

Would that be true?





Thanks

Any other countries do this idiotic ‘daylight savings time’ change?

Hello. I have a set of JSE in the closet.
Someone blew a tweeter and I bought a replacement years ago. The new tweeter did not fit the baffle the same way. With no router... I'm thinking find someone to repair the old one. Does anyone know who if anyone is the guru on high end tweeter repair? Thank you.

Hello everybody


A friend of mine given me a old SU-V2X. I've noticed that this amp runs very hot, even on low volume.



It was working fine until the moment it made a clic and enter into safety mode.


I had a look on the net on what could be the root cause and, to stay on the safe side, changed Q501-504.


But no, luck, the problem is somewhere else.


So i did check volatges ou the STK2038 and got strange results


Pin 12 gives 31,4V (supposed to be 1.8), pin 14 : 34.3 (suppesod to be 0) and pin 16, 35.2V (suppsed to be 1.8). All other are according to service manual.


I suppose that the safety feature is detcting this values.
Now, what could be the root cause ? Can you help ?




Any advices are welcome.


JM

I simulated an FLH driven by a couple of dynamic drivers in series. Please let me know your comments and opinions.
Thank you.

I don't know what fiberglass looks like.
So I'm guessing. Is it fiberglass?(see photo)
this cloth is from cheap school/travel bag.

Hello, in my SE EL34 amplifier I have a pretty flat frequency response (within +/- 0.5dB +20Hz-20KHz, measured) and with full GNFB, I reach a minimum of 0.15% THD% at 1KHz @1W on 8.2 resistor.

But if I measure THD% at 50 or 100HZ, distortion rises to 1.5% @1W on 8.2 resistor. Why?

I don't understand if it is incorrect measurement or it is normal, or bad O.T. or something else.
Thanks

Here is a very nice pair of Japanese Tamradio Tamura Single Ended Transformers from the sixties. These sound fantastic and have 8 and 600 ohm secondaries. The primary is 5K and 60 ma.

I have used these before in amps and they sound and work great! These are much better that modern equivilents.

$130 plus shipping. I am in Vienna, Austria.

Paypal friends and family please or add 4% for fees.

Please feel free to ask questions.

Thanks! -Mac

I was given a Bush subwoofer from S21192. The unit had a 5" driver in a cabinet measuring 20cm x 20cm x 25cm. I replaced the driver with a 6.5" unit from an Acoustic Solutions AV-120.

Unfortunately, I do have the specifications for either drive unit other than the Acoustic Solutions AV-120 bottoms out at 48hz in a floor-standing cabinet.

The results are okay but the bass ain't going to trouble the neighbours. Because the cabinet is so small would I be better off removing the port and converting a sealed enclosure?

Or should I discard the port in favour of 2 x 4" passive radiators?

Hello and thanks for any assistance! I am in Mexico and have built a mini golf / bbar concept. I realized my sound system was lacking and hit Ebay after doing some research. Well I did not do enough research and I do not want to blow the equiptmet I have purchased. Here is what I have:

Mixer:
Pyle pmxu83bt
AMPS:
tpro LZ10k 10000 watt
3065 @ 2ohm, 2125@4ohm, 1350@8ohm
Tpro Ax3000 3000 watt -550@4ohm, 800@2ohm
Monoprice 8ohm 150 watt x 2 rms
SPEAKERS:
2 ROCKVILLE 15.24 3WAY PASSIVE 4 OHM 3000 PEAK - 1500 RMS EACH.
2 ROCKVILLE 15IN PASSIVE SUBS 800 WATT 400 WATT RMS EACH - 4 OHM
2 ROCKVILLE - KPS 12 - 3 WAY - 8 OHM - 200 WATT RMS EACH

ADDITIONAL EQUIPTMENT:
BEHRINGER SUPER-X PRO
TPRO RACK POWERSUPLY
HERCULES DJ CONTROL
AND MORE CABLES THAN I NEED FOR SURE.

WHAT DO I NEED?

HOW DO I SET IT UP?

I DO NOT MIND PURCHASING OTHER EQUIPTMENT IE AMPS
Hello and thanks for any assistance! I am in Mexico and have built a mini golf / bbar concept. I realized my sound system was lacking and hit Ebay after doing some research. Well I did not do enough research and I do not want to blow the equiptmet I have purchased. Here is what I have:

Mixer:
Pyle pmxu83bt
AMPS:
tpro LZ10k 10000 watt
3065 @ 2ohm, 2125@4ohm, 1350@8ohm
Tpro Ax3000 3000 watt -550@4ohm, 800@2ohm
Monoprice 8ohm 150 watt x 2 rms
SPEAKERS:
2 ROCKVILLE 15.24 3WAY PASSIVE 4 OHM 3000 PEAK - 1500 RMS EACH.
2 ROCKVILLE 15IN PASSIVE SUBS 800 WATT 400 WATT RMS EACH - 4 OHM
2 ROCKVILLE - KPS 12 - 3 WAY - 8 OHM - 200 WATT RMS EACH

Additional equiptment:
BEHRINGER SUPER-X PRO
TPRO RACK POWERSUPLY
HERCULES DJ CONTROL
Tons of cables…
Question?
What do I need?
How do I set it up?
Notes:
Completely open to the fact that I should have done this prior to purchasing, and may need additional or replacement equiptment now. Just need to know what to buy. Feel free to let me have it, as I definitely deserve it!
Sound area is large and open. Think beach bar.
I do have my 18th hole which is a 12 ft x 12ft cement pyramid that is dying to be a huge sub cabinet some day soon.
Any assistance will be gladly repayed in full during your next trip to Costa Maya Mexico. Drinks on me for sure!
HELP!
Poco Loco's
Mahahual, Mxll

Hi All,

I have been looking at some cheap 2nd hand transformers on an auction site, and I am left a little confused about the voltage ratings on center-tapped secondaries.

Is there a clear and consistent way the secondary voltage is rated?

Exapmle:

Triad R-23J transformer with the spec printed on the end-bell:
250V @ 22mA Center Tap

I would assume this means that the transformer is 125v-0-125v

But the seller claims it is 250v-0-250v.


Any thoughts on this? Were there historically different ways the secondary rating was expressed?

Thanks!

regards,
John

For the fun of reading on vintage stuff ... does anyone have a service manual or just schematics for Sony's first Class-d amp TA-N88 (running 500 kHz! and with SMPS .... 😀 )

I can only find this very high level schematic
http://toragi.cqpub.co.jp/Portals/0/backnumber/2008/03/p130-131.pdf

Thanks in advance
Baldin 🙂

Hey diyAudio!

I recently purchased a douk audio 6N2/EL34 tube amp kit to dip my toes in the world of tube power amplifiers. It arrived, and I built the kit, however there was absolutely no sound from either of the output transformers. I (probably retrospectively should have looked through the schematic and tested the PCB, but waiting nearly a month for shipping and my eagerness got the better of me). When I did sit down to crunch the schematic, it seems like there are some unusual things happening around the power stage for a single ended amp (in comparison to the other SE EL34 schematics I was referencing). I was hoping you good folks could take a look and see if there are any major errors in the design of this. I tested all of the resistors and capacitors before building the PCB and they were in spec. Just wanted to verify that there were no design errors before I went ahead and bought some replacement tubes.


Quick note: on the schematic, I have written in pen what connections to the tube sockets the PCB traces had using a multimeter set to continuity, but comparing it to a normal EL34 data sheet it looks like the socket may not be wired correctly.


Thanks in advance!

From audio express magazine September 2019

Attachment replaced with the link below:
AppNote: Loudspeaker Electroacoustic Measurements - Audio Precision

I have few modules for a very good Class AB amp. It's designed by my friend Aniket also a member here. The stereo amp has onboard power supply and protection circuit and comes with 2 X PCB mounted heatsinks. Just add a case, transformer and other hardware. It's almost plug n play.
I have two power options 100W/channel and 75W/channel
BJTs used for 75W Toshiba 2SC5200N/A1943N
Power caps , 4 X 6800uf, 50W

Bjts for 120W: Toshiba 2SC5949/A2121
Power caps , 4 X 10000uf 63W

below are the specs of our stereo amp:

Power output : 70~120W into 8 ohms, 110~180W into 4 ohms.(continuous avg per channel.)
THD : <0.03 % at rated power 20-20000Hz, 0.003 % @ 1kHz half power
Signal to noise ratio : 112dB
Frequency response : 3Hz-250kHz.(-3dB)
Input impedance : 25k ohms
Input sensitivity : 1V rms for rated power
Damping factor : 200, @ 8 ohms, 20-500Hz
Transformer for75W : 30-0-30, 300 9-0-9V AC for protect
Transformer for 120W : 40-0-40V AC, -500VA, 9-0-9V AC for protect
PCB size Power Amp : 280mm X 120mm






Prices
75W/ channel $110
120W/channel $135
Shipping $20 by Registered post,
The modules will have all onboard parts, including 2 X heatsinks, connectors, fuses etc

Regards
Sachin

here is the jist of the story
my nephew inherited an old building and he is a band manager ,he used to do a lot of studio recording and have asked a few friends to help him but they don't know what to set up for a small live sound space ,so he asked me as his mommy will pay for the costs and i am dragged in this because she feels like sonny will be ripped off.
the space has around 12 ft ceilings with wooden rafters,room size is about 70 x 30 ft
the ceiling is a bit higher around the planned stage area(15 ft)
his idea is to have a very high quality sound system fairly full range and mommy is willing to spend a bit(75k to 100k) so son can have a new career as a club owner
i can help a bit with the interior and some speaker choice so any turnkey ideas welcome
p.s he feels like he wants a vintage tonal sound
so please recommend
foh speakers(i love multi cells )
subs
amps
stage mixer (maybe a 5 pc band)
sound board maybe 8 channels(they would like to do some live recording streaming)
snakes
monitors
mikes
lighting
wireless options etc
any help appreciated
thankx
my background is engineer and i did lots of live sound in the eighties and some studio mastering experience

Have anyone add coax input to the deq2496.

I think it would be possible to tap into the ak4114 RX0/RX1 input for the coax in. Refer to page 22 on ak4114 datasheet for the optical receiver input (with 470R) which is same as the optical circuit in deq2496.
It looks it I can solder a coax wire on input side of the 470R resistor (connected to the RX1 pin of ak4114) and put a 75R across the coax wire and put a BNC at the wire end and I am done.

Anybody done this yet?


...chuck

Need to have 1 db step attenuation for balanced line level signal

0 to -12db attenuation would be great. 1 db steps would make precise leveling of left and right channels.

Can you guys recommend a way to do this? Stepped 2 ch. attenuator per one BAL ch?


thanks,
Herman

Quite a while ago I built a single 18" sub to use as a drum sub, with a single stage monitor on top, for drummers in a live situation. Basically to reinforce kick drum for the drummer. I've recently pulled it out and replaced the 18" blown driver with a 1000W driver. I also bought a 1000W, 125Hz, low pass filter on Amazon. Question, what is the best way to provide a simple, speaker protection scheme to keep from blowing up the 18" driver. I really am looking for simple. There is quite a bit of DSP built in to the amp I'll be driving it with, which I will use, but if I could maybe add something to the low pass filter that would be great.

THE WOLF SONG - Nordic Lullaby - Vargsången

What do you think about Jonna Jinton who lives in the north of Sweden far out in the wilderness. She is really good in filming and editing, don't you think?

I have been following this thread here: Kicker 083ZX1000.1 output trouble but have only had to repair maybe 3 or 4 kickers so my expierience is next to nill with these.

I have a zx1000 dated 6-1-06. I dont believe this one has a 0 ohm jumper between speaker ground and Ground terminal if that helps.

I have .98 amps when powered and relay engages. It clicks once.

I dont believe the protection light is working but I do see a square wave on the the protect pin.

I have 1.5Vdc between speaker - and speaker +

I do have 1 fet per bank installed because Q105 and Q107 were shorted so I pulled Q106 and put it in Q105.

This amp came with FQA44N30 and I dont have any. The closest I have is FDA69N25 and was unsure if those would work for testing. The gate charge, input capacitance, and rds on were a hair lower than the FQA44n30.

The inductor got so hot that the solder shorted to the drain of that bank. I have a photo attached.

I was seeing drive from the Class d control board. Only seeing 1.6V from ground on control board to R122.

Lifting D7 did absolutely nothing for me.

SOLD

SOLD

Vid: YouTube
CHICAOG, March 16, 2020 – They say it’s the “Mother Of All Volume Pedal Mods.” Zeppelin Design Labs in Chicago has released a makeover mod for your Ernie Ball VP Jr. Pull out the scratchy pot and broken string and replace them with a magnet and a Hall effect sensor. Together they detect treadle movement without using any mechanical parts. A microcontroller uses the position data to control a pair of optocouplers to alter the volume of the audio signal, all while retaining a pure analog signal path. This mod also buffers the audio signal and offers up to 14dB of gain.

You can build the mod from scratch from an affordable DIY kit (intermediate soldering skills required); or get the mod assembled and ready for you to install into your Ernie Ball VP Jr with not much more than a screw driver; or send in your pedal and the folks at Zeppelin will mod it for you.

“The string in my Ernie Ball once broke in the middle a show,” says Brach Siemens, designer of the VPM 1. “I promised myself that night that someday I’d develop a solid-state solution – I never want that to happen again.”

By controlling the all-analog signal path digitally, Zeppelin Design Labs was able to incorporate some incredible features into this mod:
• Choose from five different volume taper curves: linear, two logarithmic curves, and two reverse logarithmic curves.
• Set the maximum- and minimum-volume points to any position along the treadle movement for fully custom response.
• Reversible treadle action.
And if all that is not enough for you, there are even two optional upgrades:
• The Expression upgrade equips your VPM-1 to act as an expression control, compatible with a wide range effects pedals.
• The Stereo upgrade can be configured for either traditional stereo mode or panning configuration.

The DIY kit starts at just $69. The pre--assembled mod starts at $120. Full service mods start at $165.
The VPM-1 is available direct from Home - Zeppelin Design Labs, and also on Reverb, Etsy and Amazon.

Twisted Pear Audio Placid HDBiPolar (completely build and tested, fully operational, set to +/- 15 VDC) with toroidal power transformer - $100

IFi iPower 5 VDC linear wall wart power supply, like new, in box - $25

K&K Audio 5VDC, 2 A, 12 watt power supply, completely built fully tested and operational - $50

DIYINHK LT3042 dual power supply, 3.3 or 5 VDC, completely built and functional, one cmc bypassed, the other removed, it sounds better that way - SOLD

DIYINHK TPS7A4700 dual power supply, 3.3 or 5 VDC, completely built and fully functional - SOLD

Toroid transformer for either of the DIYINHK boards above - $20

My soldering is perfect - 40+ years of experience, military and AT&T/Bell Labs trained.

Plus actual shipping, but will combine shipping, prefer US.

Today reading about the Audionet power amp HEISENBERG top line.
Iread ULA technology (Ultra Linear Amplifier) for real-time linearization of distortions.


Who can explain what is this.



HEISENBERG - Audionet - Say my name

I am using Rod Coleman's regulators in my 6J5 input 45 output parafeed headphone amplifier. The 6J5 will have a cascode MOSFET CCS load, the 45 will have an EL83 pentode CCS load (ri of the EL83 ~260K).

I am trying to decide if I should use dedicated transformers for the 45 filaments, i.e., the Hammond 266L12, or include the two 6.3V / 5A windings on the custom mains transformer I am having made by Sowter UK.

Talking with Rod, if the windings are on the Sowter transformer, I do run the risk of having rectifier noise from the raw DC supplies (also Rod's design) coupled to the B+ supply and having it appear on the plates of the tubes.
Given both input and output tubes have active plate loads, PS noise rejection should be good (especially the 6J5), this is my preferred route. So...

Option A: include two 6.3V / 5A windings on my Sowter mains transformer and trust that my EL83 pentode CCS will reject the raw DC rectifier noise on the 45 (the MOSFET CCS on the 6J5 should take care of it no problemo)

Option B: mount the Hammond transformers under the chassis, possibly subjecting my internal components to their sizable magnetic fields - would try to minimize by optimizing the internal layout

I don't have the experience to say which of these two options is best, would love to hear from those who do, thank you.

Tile says it. Best 8 inch full range driver for a TQWT transmission line.
Assume up to 200 dollars per driver.

Thoughts?

Dean

hi

I'm building a DIY TT and I'm looking for a high quality DC motor controller.
Mark Kelly's versions aren't that easy to get hold of. Hagtech is developing one but I don't know how it's coming along. It shouldn't be to difficult to build for a novice eather...

Came across Maxons LSC 4-Q-DC Servoamplifier and ADS_E 4-Q-DC Servoamplifier.
Would these (or other Maxon stock controllers) be a good choice for a TT)

Hope someone can help (I'm planning to use a Maxon (type?) motor and belt drive.The platter will be aprox 15kg)

best regards

Hello.
I will add a second channel on my mic preamp.
I want to wire it like that because I don't want to use 2 input transformers (pricey).

I don't know if I created a ground loop, between the "normal channel" and the "low channel" ?
Is it a good way to do it ? If you have any suggestions on a better way please feel free.

Thank you.


EDIT : Do you know if using an ECC81 will be lower noise as the input stage than ECC83 ?


The schematic :

Hi everyone,

i was given two cheap, but identical 650VA ups units with broken batteries.

While salvaging parts, it occured to me that i may be able to make an isolation transformer, using the two identical transformers back to back.

I know it won't be able to supply a lot of power, but i'am ok with around 100 VA, just to be able to scope mains stuff without blowing up everything. The transformers look like about 150 VA each.

Now, each primary has the following taps: 0V, 185V, 220V, 255V.

The secondaries read 7.1V, 0V, 7.1V (center tapped), and there is also a low power separete 19V winding.

I will use the casing of one of the units to enclose everything, as it already has a mains power cord and a convinient mains outlet, and even a fuse holder!

Any ideas how to wire them up for testing?

I suspect that i don't need the 0V center tap of the secondaries, and i should be carefull with the 19V secondary polarity.

Of course i'am going to test it with incandescent lamps of 25, 40, 60, and 100 Watts to see if the voltages and the temperatures are ok.

Any ideas greatly appreciated!

Dear All,

I’m struggling to get the circuit below working after making some updates. My main purpose is to have both relays switching after a delay. The delay has been build around a BC547C transistor and a small delay network.

The problem that I have is that only the Omron rely is switching, the Zettler is not working at all. When measuring the delay circuit it is working and supplying the 5V towards both relay coils.

I’ve been thinking about the current supplied by the BC547C, can it be that the current possible to flow is too limited to get both relays switching? As I’m using two different relays with slightly different coils the Omron works first.

Hope somebody can troubleshoot my diagram. Please forgive the simple way of drawing as I’m not educated in electronics but learning by doing and reading a lot on the internet.

Relay types are:
- Zetler AZ822–2C–5DSE
- Omron G5V-2-H1

Thx in advance!

I have an early version of the DSL50 jcm2000 amp to which there is no reference anywhere...printed out the schematics I could find but there are too many differences in denomination of the components and wiring lugs. Anyways I'll state my findings, initial problem is that the channel switching doesn't work at all, the LED doesn't turn on either...so basically its stuck on the clean channel. I tried powering up the amp just to see if it was working at all...it does sound very flimsy and bad so powered off and proceeded to do some tests. HT, heaters and bias voltage seem to be ok. It's just the LV that seems dead. So tracking from the PT LV lugs I'm getting around 21vAC through to the rectifier diodes D6, D7, D8 and D9. On the other sides of D8 and D9 I'm getting around -58vDC and on the other side of D6,D7 I'm getting 0. So I replaced them but still the same readings.
So my question at this point is... am I getting the right AC readings off the PT? If so, since the amp has obviously been tampered with in the past by someone else, did they solder the PT LV wires to the right lugs on the board? W9, W10 and W11 are the lugs used on the board but on the schematic these lugs are denominated W11, W12 and W13. There are other proven factory differences between the board and the earliest schematics so for that side of things I think everything is fine. The other difference I noticed are C6 and C37 are on the board both electrolytic (they have been replaced with 10uf 450v) which I guess is incorrect as C37 on the schematic states 47uf 63v so again too many inconsistencies to be able to rely on any versions of the schematic.

thanks for any help at all

As it says....on the hunt for a pre-amp to go with my JLH Monoblocks project!
In the short term, I still have my Crimson Pre that I assembled from a kit back in the 80's.
Seems to be so much choice out there, not sure what to focus on.😕
I'm hoping that I might get some help in narrowing the field somewhat!!
Whether it be an assembly job, from a kit of parts....or selecting suitable PCBs and going for a straight build...I'm up for a challenge🙂
BTW...Don't have access to a scope...but have a good DMM (FWIW!)


Any pointers would be much appreciated.

Hello all,

I have started to build this HPA maybe with built in USB DAC and whammy style CRCRC PSU with 24V regulators (post 82) - List of best DIY Headphone Amplifiers

Also, I have attached my LT spice schematic.
I have a question on how to better match transistors - by pairs as suggested by W. Marshall Leach if its not possible to match all of them? I have various manufacturers BC 550/560 - Fairchild, Philips, ON - but pnp and npn have different Hfe...
q1,q3 - q5,q6 , - q2-q4 ?

thank you!

Is the KORG B-1 Balanced Preamp a good match for the XA 25?

Does anyone know the cost for parts and suitable chassis?

Can this model employ the 6NS7 tube?

Would there be a remote possibility?

If a man knew his limitations and looked to hire an experienced
craftsman to assemble the piece, is this a flat fee agreement typically?

Thank you for your expertise!!

Hello,
I have to change (eliminate) a delay circuit of a B+ supply for a simple resistor with a manual switch. The delay is not working properly and I have tried already to start up the amp with two 50W 100 ohm resistors in series, switching it off the line after a few seconds. Sound quality is way better than with the delay circuit in the system. The resistor is between the 220V AC line and the primary of the B+ transformer, which has a secondary with 630V/250mA-0-630V/250mA. It is used with a full wave tube rectification, with two 5R4WGY tubes. It has a choke input that makes the PS draw a very large load when it starts up, which is too much for the tubes, hence the need for a soft start.

I would leave it like this if it was not for one thing: if I don't switch the resistor off the circuit it gets very hot. I can't recall how to calculate the needed rating power of the resistor. The 200 ohm resistance seems to do a perfect job for a soft start after about 10 seconds. Can someone help?

Thanks!

This discussion has been split from this thread Aino gradient - a collaborative speaker project

Juhazi said:

Ah, when I met SL in 2013, he naturally encouraged me to do dipole woofers too! LX521 was new then and I also knew of gainphile's work. I said no thanks, I don't have enough room for dipole woofers. And I haven't changed my mind. As well I have a huch that real radiation pattern wouldn't be dipole anyway, 20-200Hz so close to the floor and walls. Wuold that really be any better? I guess I'll never really know...

A friend has double 12" woofers in H frame like SL Orion. They sound good in his room and he plays louder than I. He has set tile bricks on them and cone movement looks really wild, but they don't vibrate much. W frame with 90deg helps a lot for LX521, but vertical slot would be totally force-cancelling. That's what I would make.

Gainphile: S19 4-Way Dipole Radiator

Click to expand...

Thanks for that.

Actually, I think it is indeed dipole into the bass -- haven't measured but walked around with <100Hz tones, and there's a distinct level reduction when listening at the sides of my Orion 3.2 as well as the M-frame dual 10" dipoles I'm experimenting with.

A local buddy who's an active member here agrees with me that there's something special about the sound of dipole bass -- more natural, somehow, than any of other bass loadings, even after all the EQ boost needed to compensate for the dipole cancellation. It just sounds more realistic -- better than serious implementations of ported, twin coupled cavity bass, sealed, aperiodic, TL -- if memory serves correctly. (I haven't heard serious horn-loaded bass; that might be even better.)

Anyway, I've decided to make a pair of Linkwitz / Gainphile W-frame bass boxes. Move the Dayton subs (same ones gainphile used, incidentally) to the new bass bin or try 10" SBAcoustics I've had on hand for ages. (But I haven't given up the idea of cloning your Aino gradient, either. 😉 )

One thing about Gainphile's W-frame: It makes sense to me to keep the volume in the front and back "chambers" about the same, but that's not what he has done; the back-facing openings appear about double the size of the front one. He's obviously happy with it.

In contrast, Linkwitz's dipole sub is much closer to having similar volume in the front & back "chambers".



Anyone have any thoughts on this?

i need help with a no power cxa600.1 No power, no protection led of any kind.
the power supply mosfets are removed and the r68 4.7r resistor is removed.
ic3 is also removed.
no drive at pin 9&10 of the 494

I am selling a Brand New Pair SB Acoustics Satori 6.5" Woofer Driver MW16P-4 MW165DC-08N36-DA00 in the Original Boxes.

Asking $300.

I am the original owner and bought them from an authorized dealer a few years ago.

They are never mounted them or hooked up and factory perfect in every way!

Too many projects on hands and no time for speaker building so I am offering them up for others to build.

I have cloned the entry Croft Acoustics phono stage with two 12AX7 and a simpel mosfet series regulator. PSU is in seperate box. I was dissapointed with the sound It was very muffled and unclear.
Then I reused the psu, and build the phono stage L2 from AudioNotes preamp kit with a 12AX7/12AU7:
Audio Asylum Thread Printer

Same story It also sounds very muffled, undynamic and unclear. I have not used audiofile grad components, but those in the croft was also standard components.
I see that It is very high impedance circuits, the first tube have to drive the RIAA filter and also the grid of the next tube through many hundreds of Kohm is´nt that a problem?

Tubes are new EH types. 12V heater supply is simple with LM7812 regulator.
Riaa curve of the Croft clone was meassured by a friend with a setup for that. It was not very precise but quite ok I belive.
I have tried to drive It with step transformer and an active stepup with same result.
I have been through the circuits severel times and belive it is build correctly.
I would like to have som input from more experinced builders?

I am trying to design my first loudspeaker project inspired by SVS subwoofers, but I find their port configuration does does not match the theory I have been told. What am I missing? If I try to follow WinISD blindly it is going to make my ports multiple times longer than what I see in a real life SVS. Now just to keep things simple, lets not talk about my design, but just try to apply the theory to the SVS PB16-Ultra.

I am told the relationship between the various quantities that allow one to tune a port in a sub-woofer enclosure are described by the Helmholtz equation:

I am told that the effective diameter of multiple ports is found by:

In the SVS PB16-ULTRA (see a cutaway here and official webpage here ) to solve the above equation we need the following information:

• Port Diameter: The subwoofer has three 3.5 inch (.089 m) diameter ports
• Volume: The subwoofer has external dimensions 25" (H) x 21.7" (W) x 28.3" (D), lets say that 30% of that is the ports, walls, and driver, so that would leave 0.176 m^3 of air volume.
• Port Length: Eyeballing the cut-away from the video I would guess that the port is about 20% longer than the longest dimension of the enclosure. Lets call that 28.3" * 1.2 = 0.86 meters

Solving for effective area we get:

Solving for the tuning frequency:
That seems a bit high for something that is trying to extend down to 14 hertz. Perhaps if we change the length by adding some port end corrections
17.7 still seems pretty high. I find that I have to tune down near 14Hz in my design that's quite a lot lower.

Lets also consider port velocity (equation is from here, constant differ to convert to metric units):
I most often see people suggest that v must be less than 0.1 and should ideally be closer to 0.05. Solving for the SVS subwoofer we need an estimate for W. Lets assume the sensitivity of the driver is 98 db per 1W @ 1 Meter, and its rated electrical power is 1500 RMS.
Solving the above
Solving for velocity at the tuning frequency I would expect and the one I calculated above:

These are clearly way too high to be realistic. They would be chuffing constantly if the air speed was ~20% the speed of sound. What gives? Perhaps there is something about having three ports that is not captured by this equation?

This is a pair of Coral Holey-basket fullrange drivers from the 60's. These are marked Sony and are 8 ohms. I have had many pairs of these over the years and these are absolutely the nicest pair I have seen...

They are 8 ohms and sound great. Alnico magnets and nice soft surrounds.

These are great drivers and quite hard to find.

$95 plus shipping. Paypal or bank transfer. Ships from Vienna, Austria.

Thanks

Hi everyone, I'm new here and need some help repairing my P2100 amp.

Random noise (attached) appeared only on one channel. Its level is constant and does not depend on volume pot position, but I noticed, that after switching off (breaking the mains) and while the sound path is still "on" for 5-6 seconds until the total shutdown - there is no noise and audio signal is clear as it should be. First guess was - one of the diode pairs DC10-1/DC10-1R, so replaced them both to 1N4007s paired accordingly, but nothing changed...

...any ideas? Appreciate any help


Thanks a lot!

Dear builders,

I have been playing with the idea of building a tube amplifier on a vertical plan. PT and OPT's can be bought cheaper, without covers (they sit on the lower floor, inside the case), tubes on top, the foot-print would be smaller. Would be valid for a pair of monoblocks or a stereo amp. An integrated amp would maybe have the input module and tubes at the back, the power tubes at the front (or the other way but then input cables are longer from back-sockets).

I have seen a few examples online :

• The 6EM7 Vertical Amp | Cascade Tubes (Matt's nice woodworking)
• 300B Amplifiers by Thomas Mayer - VinylSavor - Thomas Mayer (Thomas Mayer of Elrog fame)
• Reference 750 SEL Mono Amplifier from Audio Research (look for the pic of the opened sides)

I'm not really trying to re-invent the wheel and if it's a stupid idea go ahead and explain why... I'm always learning. I have a Tubelab SSE amp that needs casing and I'm wondering if this would be doable. So far I have built two Millett's engineering amps and their footprint is on the large side of what people see as ok.

Hey everyone, I'm new to the forum. I found this site because I run a blog on keyboards and someone asked a question about cleaning a PCB. That actually inspired me to write an article about the dangers of using acetone.

Anyway, this site is cool and there's lots of interesting topics here. I plan to stick around and maybe answer some questions from time to time.

Thanks for having me.

Anthony.

The Hypex Fusion thread is so huge, I can't tell if this question has been answered...

Is the Omnimic compatible with the Hypex Fusion amp? I can't seem to get the HFD software to recognize my Omnimic.

I have a vague memory of something I read in one of these threads which discussed this issue... ?

BTW, the (very) preliminary listening with my new FA253 has gone really well. The HFD software is easy to use. The build quality of the Fusion amps are very impressive.

I recently heard a TP-60, and was impressed. I prefer DIY, kits, or assembled boards though, and I need a bit more power if possible. I'm just wondering if there is an option which allows me to have even better than the TP-60, in a DIY form ?

I just fell in love with Tripath sound, and want to build a simple amp. Thanks for any help.

PS; The Tripath FAQ Wiki thread would not work for me.

USB iFi Ipurifier 3 - SOLD

This is the version 3 of the iFi IPurifier3 for USB audio.
Volumio web site recommends this filter between RPi or else and DAC.
Only 1 hour use.
Included with 2 USB 6 inches cables.
Bargain Price : 75$ + shipping

Fab

Hi,

I have a studer A730. After playing about 1.5 hrs, it start to skip. Also, at the initial power on, I could hear over my speakers that wheel spinning. Not sure what are the cause..... any recommendation or know of any tech that the look at the cd player. thanks

Thomas

Hi to everybody , My CD player Revox B226 has topped reading CDs .
When I try to play a CD it spins for a second and it stops.
I read all the forums available but I noticed that my CD player is a little different than the one described by the guys in the Forums.
Someone suggested to change 5 X 16V 33micro capacitors. But I don't have them .
I attach some photos, can someone helping me to find the value of the capacitor in the laser area? Thanks in advance