Hi, this is my first post here so please humor me, thanks.

I recently put together my first amp based off of this circuit using the TDA2003a (I know there are better IC's out there). Overall things went well and I got some good sound out of it on the first try, albeit with some obvious issues. Two of these issues started only after I installed a potentiometer for volume control.

The first is a buzzing/popping when no input is connected/poor connection. I presume this is a grounding issue and could maybe be solved or at least minimized with a resistor from signal to ground near the pot? (This happened before I used a pot as well, and I had thought that the 56k resistor in the circuit would mostly prevent this but I guess not).

The second is a constant buzz even when an input is connected, the volume of which changes as I turn the pot. This only started after I added the pot so I think it's a grounding issue?

The third is an additional fainter hum that happens when touching the metal knob on the pot, which I at least think is related to the same grounding issue as the previous problem.

Any advice is appreciated, I can provide more details if that helps!
Thanks!

I'm tweaking and refurbing my 2.1 system. The Sony 2-way satellites (6 ohms) have a simple capacitor on the tweeter 1.8 uf / 100v. I have a pair of 2-way cross-overs salvaged from Toshiba. Also 6 ohms, the components are: an inductor, a 5w resistor (4.7 ohms) and a capacitor (2.2 uf / 50v). Is it worth swapping them?

I have a problem with an Ampex 601 preamp, when I turn up the gain past about half way it starts oscillating (MIC. REC. LEVEL on the schematic, just after the first tube, which is a 5879).

I tried changing the 5879 tube, and cleaning the socket. I have already changed the two proceeding 10uF power supply filter caps. Using a cheap oscilloscope, after the input transformer it looks fine, but anywhere after the tube I get the bad signal. I plan to also change the 20uF filter capacitors as well.

I then changed the potentiometer itself and the .1uF capacitor before it, to no avail.

As it happens when I turn the gain pot up, what does this indicate? Does this necessarily mean it must be a problem before the potentiometer? I am quite a novice, but since the resistance increases, does this mean that more current is drawn, so it could be a power issue? The only thing I haven't changed now around that tube is the cathode bypass cap, and the resistors, but before I proceed what do you think is most likely to cause such a problem? I guess the second tube I tried could be wrong too, but it seems unlikely, and changing it produced no effect.

Thanks

I am trying to complete a power supply for amp camps and realized the traces on one of my PSU boards is damaged, so I’m looking for a single (or pair) of Rudi’s Red CapMX PSU boards to replace the damaged one.

I’m willing to buy a pair and if the amp camp premium boards are included I would also take those.

Looking to get them in the US.

There is nothing mysterius about it.
Just an Class A amplifier with good data.
10 Watt into 8 ohm.
Spice simulation shows THD 0.00006% at 1 Watt output.

You would not regret if you build it.
The Sound should be very good.

Some time ago I bought from a seller on AE this power supply with a 9VDC output, however it was also available with different output voltages.

Currently I would need a 5VDC output and the seller told me to get it by turning the trimmer highlighted in the picture, but it requires many turns for small changes; anyway after so many turns then it stands on 8VDC and does not seem to go down more than that.

Is there a reason for that?

Is there a way in order to get 5VDC output from this power supply?

Thanks in advance for any addressing.

Repairing a RCF hdl-20A amp module and wondering if anybody has a schematic for this amp or where I might be able to get one?
Thanks
Chris

I am beginning a project to make a good sounding speaker system, I am looking for products that hit way above their weight and while I cannot audition every tweeter and mid on the planet I can look at the measurements that some amazing people put online for us to benefit from! I have started a spreadsheet with what I am considering some good metrics for a potential mid/tweeter. Spreadsheet

The project is meant to be full range, or darn close to full range so there will be a sub woofer, it is currently chosen as the Morel MW 1058. I bought a couple of these on sale for a great price so I'm using these. If there are better subs I am open to options but I like them so, so far so good!

In terms of Mids and Tweeters I have listed some of the best measuring speakers and catalogued them, I will be adding to this list but its a start for me to keep track of different available speakers that have better measurements.

Obvisouly measurements are not everything, but I would assume that of all the drivers in all the world the best ones also measure good. So I am eliminating drivers that measure poorly off axis, have bad step response and have higher than normal distortion measurements.

At this time for mids I would like to spend less than $200, maybe $220 or so. For tweeter less than $200, ideally less than $150. Many of my list are much higher than this but I just went by measurements and figured the price out later to as to not bias my decision. For instance the Morel CAT tweeter looks bad on measurements but its on the list, I was biased!

So if you have any driver suggestions I will add them to the list! I went to hificompass.com for measurements and will be seeking other resources, do you know of any resources that have comprehensive measurements? I will look there too!

This will be an active system using the Dayton 100x4 w/DSP amp. At least for now until I find out it sucks, if it does. Crossovers would likely be in the 80-120hz range and 1800hz range. At least that seems to be a fairly safe range on most speakers graphs. Each speaker will get 100 watts and the sub 200 watts. 100x4 amp for each speaker. I know it likely won't push 100 watts and thats fine. I have the 36v 10a PS for the amp as well.

Notes for the spreadsheet:
Mids: I am looking for fairly flat speakers, they don't have to be super flat but flat enough, I looked at the 80hz to 2000 hz for the mids and measured peaks and troughs.
Step response to find drivers that recover quickly, likely not the perfect measurement but its something.
Harmonic distortion measurements, I looked in the 80-2000hz range and guaged it.

Tweeters are similar, but the range changes. From 2k - 10k is usually fine, but from 10k-20k things get weird most of the time. I would assume the better tweeters do a better job and these first data points are all off axis dips in response.
Step response for the same reason and also Harmonic Distortion.
I also took liberty to rank tweeters based on 3db down like we do with subs. Just on the high end! So I listed the frequency that they go down 3db. At 0 and at 45 degrees.

Any suggestions would be appreciated, I know speakers don't sound like their graphs, its just the starting point, I will buy several drivers to test them out and see if they have a good sound after this selection process.

Note: Pictures start here 15th Annual Vancouver Island diyFEST-2018

August 25th in the usual place. (up the mountain in Victoria, BC out in the forest at my place of residence/workplace)

Some people have been making this a weekend long affair so we expect some people to arrive Friday and not leave till Sunday.

People camp, stretch out on the deck, or claim floor space in the living room.

dave

For those who want to get an idea of what these are all about:

14th Annual Vancouver Island diyFEST-2017
13th Annual Vancouver Island diyFEST-2016 - diyAudio
12th Annual Vancouver Island diyFEST 2015 - diyAudio
11th Annual Vancouver Island diyFEST 2014 - diyAudio
http://www.diyaudio.com/forums/clubs-events/233677-10th-annual-vancouver-island-diyfest-2013-a.html
http://www.diyaudio.com/forums/clubs-events/209401-9th-annual-vancouver-island-diyfest-2012-a.html
http://www.diyaudio.com/forums/clubs-events/184137-8th-annual-vancouver-island-diyfest-2011-a.html
http://www.diyaudio.com/forums/clubs-events/160514-7th-annual-vancouver-island-diyfest-2010-a.html
http://www.diyaudio.com/forums/clubs-events/139005-6th-annual-vancouver-island-diyfest-2009-a.html
http://www.diyaudio.com/forums/clubs-events/84360-pictures-report-06-vancouver-island-diyfest.html
http://www.diyaudio.com/forums/clubs-events/129156-5th-annual-vancouver-island-diyfest-2008-a.html
http://www.diyaudio.com/forums/clubs-events/100098-4th-annual-vancouver-island-diyfest-2007-a.html
http://www.diyaudio.com/forums/clubs-events/81260-3rd-annual-vancouver-island-diyfest-2006-a.html
http://www.diyaudio.com/forums/clubs-events/62437-2nd-annual-vancouver-island-diyfest-2005-a.html

I have an opportunity to upgrade my current computer speakers, which are these anonymous Roland micro-monitors with dog knows what for drivers and amp to tickle them (plastic cases, too).
Plastic cases will stay in the form of huge PVC 90 degree elbows loaded with Tang Band W4-654S drivers (ported enclosure). I'm thinking of a baby Class A amp to drive them, an attenuated version of my L'Fake phony SIT amp. The preliminary schematic is shown below.

Since I spend so much time at my computer, it's time I had more than the current Roland audio-fart generator to accompany my internet journeys....

A while back I made a clone of Mark Johnson's P089ZB SMPS DC filter in a form factor for use on top of a Raspberry PI. The filter accepts power in either through a euroblock or USB-C, and gives power out through another euroblock, a pin header, or the appropriate pins of a GPIO header. The GPIO header can provide power for RPis that have the HiFiBerry "HAT" devices. There are two jumpers to completely disconnect the GPIO header from + and - on the filter as well. Even though this implementation is amenable to use with a RPi, it is also usable in applications where a P089ZB filter is appropriate, e.g. up to 48V or 3A. Since the store is apparently out of these, and since I have only one RPi now, I have an extra for sale. It has the GPIO header installed in the position to give power to a HAT, as shown.

$10 + $5 for US domestic shipping.

I also have one unpopulated PCB left that contains only the SMT USB-C port. That's free for $5 US domestic shipping as well.

Any good ideas? No restrictions on size, no requirements, anything you got ill consider? Appreciated in advance.

thx!

Any interest in a thread on this?

Hi,

I'm planning to do a Baffle Step Compensation for my woofer. I calculated the values of BSC on the website and the website told me to use Rbsc = 6.1 ohms and an inductor(Lbsc) of 1.8 mH in parallel to make a BSC (image 1).

The problem is when I went to look at an inductor, the inductor was said it has a resistance about 1.22 ohms on it. So if I install all the components (image 2), Do I have to choose the value of Rbsc to compensate the effect from inductor's resistance ? and How is that value ?

Thank you.

Hello all. I have a Memphis PRXA1500.1 that should be coming in soon for repair but I would like to order at least the PS FETs and outputs now since I am currently placing a parts order. Can anyone confirm what these parts are in this amp either from experience, or by looking at the board and recognizing the circuit? I am leaning towards the PowerAcoustik PA3000D series of clones that can use IRF3205 and IRFB31N20D along with the MPSA56(Q124/Q125) on the driver board as it resembles that series of amps.
Anyone can confirm these selections or can guide me straight? Thanks.

Recently I made a TV stand out of wood and aluminium, and thought it would be nice if we had a pair of speakers that matched. Using T-slot extrusions would also let me avoid having to do any real joinery, which is too much effort for my lazy self. But would that really work?

To start with, the drivers: Omnes Audio CX 3.1 coaxials for the mid/tweeter, and Omnes Audio W8 Alu for the woofers (in series pairs for 8Ω total, as they are driven by an amp with a 6Ω min. load). These are nice looking aluminium cone drivers, although their matte finish doesn't quite match the silky finish of the extrusions. I chose the CX 3.1 because I wanted coax drivers, and they looked like they had less terrible frequency response than most. The woofers I chose simply because they match.



Hers's the measured frequency response of the drivers. They were mounted in the enclosure, with the mic placed 30cm from the tweeter, on-axis:



And this is the crossover:



The 1st order crossover between mid/tweeter doesn't attenuate the mid's 6.5kHz peak very much, but I decided I would accept that to make it as simple as possible, since there's (theoretically) no lobing issues from low-order crossovers with coaxial drivers.

The enclosure is made from an aluminium frame with plywood panels slotted in. The volume is 100l, with a port tuned to 33Hz.



The interior is covered with material made from recycled jeans that I had quite a lot of because it's used as packing material for some stuff that was delivered to us.



Note the enclosure for the mid/tweeter, consisting of a thick cardboard tube with a circle of plywood glued into the end.

I mounted the crossover to the rear panel, using brass rod as anchors for connecting component leads and wires together, breadboard-style



And here's the final frequency response, with one plot for the woofer/mid/tweeter combined (measured the same way as before), and one for the port (measured at a distance of 0cm from the port). I didn't attempt to combine them into a single plot, as you can get a good enough idea from just the separate plots.



And once completed and put next to the TV, they look like this:



So, it worked ok. With the panels simply slotted in, they aren't going to be fully air-tight, but it's good enough for vented speakers. If they were sealed, then I might have put some sealant or glue around the inside edges. Definitely less work than more standard construction, though routing all the rabbets took a while.

They sound great for watching films.

There are a few more images and stuff on my website.

Hello,
I want to build ported loudspeakers using two parallel Visaton BG20 drivers in each cabinet. How can i calculate the necessary volume of the enclosure?
Thank you for your help https://www.rus-tubes.com/main-page
Noyan

Hey guys, I'm quite new on this diy thing.

My friend gave me one phonic p8a without an amp and recomended me to buy two tpa3118 4-8 ohms with 60 watts and dc 8-24. One for subwoofer another for the tweeter.

However, the chip burned on all of my attempts to make it work. Except for my last attempt, which I solded both the tweeter and subwoofer on one amp output and it worked for a longer period of time.

So which amp should i use, I've been thinking on buying tpa3116 with 100w, but im not sure anymore.

as far as i know the phonic p8a tweeter has 4 ohms and the subwoofer has 8 ohms.

And i used a font of 20v of output

​

As I started this subject already with an offtopic post :
https://www.diyaudio.com/community/threads/my-germanium-based-amplifier.388996/#post-7089921
I thought of giving it a life of its own.
First 13 hours check :

Here in the UK xl cabs finished in a light grey cut out for 10.3 these were made from a kjf kit and wired with chord cable the threads in the wood could do with some small blocks gluing behind them as they are a bit slack or make a supre baffle then use a Driver of your choice, may be able to deliver or meet for fuel depending where you are i am close to Hull and Humber Bridge. open to offers

I just picked up the 7th edition of the nearly universally suggested book by Vance Dickason, and it seems to me to be written at a “201” level. Is there a similar reference book that would be “101/102” or Intro level? I can see this being helpful after a while…

$120 USD includes shipping in continental USA.

Original owner. Excellent condition. Have not used in years. Continues to be supported with updates as a streamer.

SlimDevices Squeezebox v3

$950 USD for combo includes shipping in continental USA.

Original owner. All are in excellent condition. Have the original box for the pre90. Still looking for the D90 box.
Have the remote and AC power cable.

Topping D90 DAC, Original non MQA version with the AKM chipset AK4499.
Topping pre90 preamp

Clearing out drivers. All are in excellent condition. Make me an offer:

6 (3 pairs) of Adire Extremis 6.8 woofers - $50/ea
3 CSS WR125 midrange drivers - $25/ea
3 Usher Audio 9950C-15 tweeters - $50/ea

Will ship using USPS Priority Mail in continental USA.
Can meet locally in PNW.

Glad to provide details, pictures.
These were part of the Adire (Dan Wiggins design LCR speakers). I have the crossover components as well if interested.

Hi All,
I'm new on this forum and this is my first post. I'm a not very experienced enthusiast.
I completed a first bookshelf project and this is the second one.
I bought the 3 couples of drivers as a deal and after I tried to put them together in the best way.

• Hivi M5A 5" mid bass aluminum/magnesium cone driver
• Visaton B80 extended range 3,3" driver
• Hivi TN28 1" tweeter

I know it's quite useless a 3 way design with such a small woofer and a small enclosure, but I like experiments.
So you can see the result in the pictures.
They sound good, not really punchy in the super bass region as you can imagine, but they are dynamic, well controlled and very clear at medium-high frequencies.
Medium frequencies are a little too present but they are very very clear thanks to the Visaton qualities. Also in the non optimal location in the room this is a plus.

Can anybody help me figure out how to convert a tube amp that uses 2 6V6's convert to use 6CA7's or EL34's or 6L6's

Are we running out of words to express meaning? Must we mangle exiting words instead of creating new ones? If base is bass, should treble be trout to continue the fishy metaphor.

Hi everyone,

I have been recently interested into DIY audio systems and have finished my first speaker with Carlsonator 12" design.



I have mounted Celestion K12H-200TC 12" 200 Watt Full-Range woofer (https://www.parts-express.com/Celestion-K12H-200TC-12-200-Watt-Full-Range-Professional-Wo-294-2082) along with HiVi RT2C-A Planar Isodynamic Tweeter (https://www.parts-express.com/HiVi-RT2C-A-Planar-Isodynamic-Tweeter-297-406)

The sound is amazing, however the problem I have is with the Amp.

Firstly I have connected my speaker to Yamaha RS 202 (https://usa.yamaha.com/products/audio_visual/hifi_components/r-s202/specs.html#product-tabs), which delivered very good, crisp and quite loud sound. I was very much satisfied with it, even though the amp delivered only 140W per channel and the woofer was up to 200W.

Then I decided to buy the amp board, specifically from Sure Electronics (https://store.sure-electronics.com/product/255).
It is supposed to have 300W power per channel. So I hooked it up however to my surprise this amp delivered significantly lower volume than the Yamaha. Now I was not expecting significantly louder volume, but I certainly was not expecting lower...

Sory if my confusion sounds very stupid for you, but could anyone give me any insight why this may have happened?
I may be new to reading specs of amps I am comparing...

Hi friends, here is my suggestion for quick, easy, highly efficient, relatively cheap, yet amazingly sounding 2-way.

Long story short I was looking for simple good sounding speaker for amp/preamp tweeking and comparing. I did not want to swap amps in main systems, which are biamped, and awkward to work with, so I came up with this simple 2-way.

It consists of faital PRO 6fe200 as midbas duties, and Selenium/JBL ST200 supertweeter. Box is Ikea Forloya(?) wooden shelve with front and back baffle made of plywood. Its closed with light stuffing with fibers from some Ikea pillow. Crossover is just a 2 uF cap for tweeter.

I can't stop listening to this speaker. Granted, it does not go too deep, but for comparing amps, this is not an issue. For normal listening it goes low enough. It excells in midrange and hights. It has dynamic and coherent sound. Highly recommended. Give it a try, you will not regret it.

Have a pair of Brand New Fostex 206EN for sale $230 + shipping (US 48 states) . Opened to take photographs.

SMathews

Hi Line Source
Can you help me.
I want to build a 3 way speaker with SBA drivers, so thats its not too big I want to use the SB23NRXS45-8 as the bass unit with a suitable SBA mid and HF unit.
I want to build it as a bass reflex of about 40 to 45 litres and it will be close to the back wall so do not need too much baffle step as per Troels Grvesen designs.
I want to make it 10.5 inches wide and I dont want a slanted or stepped baffle like TG designs.
The width and flat baffle are for for WAF.
Can you help with a crossover design.

Hey guys!

I'm thinking about making a GB for the turntable motor Maxon 110191. I would like to know if there would be more people interested in making a Group buy.

I'm located in Hungary, so postage in the EU wouldn't make problems with taxes.

Let me know if you're interested in buying one/multiple!

The 6E6P-E tube has an element at pin eight that consists of a very fine wire that circles about three-quarters of the way around the internal structure of the tube. It is fastened in four places on the top and bottom micas but isn't connected to any other elements. There is a description in the second data sheet at this link but I can't read Russian.

''GSTube.com''. Tubes, sockets etc. Parameters and characteristics 6E6n-DP

Does anyone know what this does?

John

his past weekend, I moved my kids Beogram 5005 in the trunk of my car. No, I didn't put it in transport mode 🙁 Worked fine prior to the move. Now, it starts up when I press the play button. The tone arm and the tracking arm move to the record and the needle drops. I can manually advance the tone/tracking arm and drop the needle also. All good. From that point, the record plays, but only the grove that it is currently in, skips, then repeats playing the same grove. It does not advance at all. I'm thinking its the bulb on the tracker.

Any help will be greatly appreciated. Thanks in advance.

DeWalt has a issued a safety recall on miter saw models DWS779, DWS780, and DHS790 with date codes between 2019 04 and 2022 04.

If you have one of these models you can receive a free repair kit or get free repair from a DeWalt service center.

I post this as I was once searching this very question months ago and did not find the answer....

First let me tell, there is some one with a famous Capacitor test that states bypass caps don't really work in passive speakers, yet elsewhere states they did make a difference once with some Vishays. I also remind you Madisound (love you guys) is wrong to recommend that shunt caps don't make a difference.

I had some B&W DM5 I was trying to rebuild and tweek. A great design with a very high flux density, exponential (good midrange) cone. In an acoustic suspension so I would not hear midrange leakage or out of phase bass when I mix or master recordings. I wanted to make these buggers work.

I bypassed the polyester in line caps and shunt caps with high voltage Polystyrene. It cleared up a sizzle in the tweeter and opened up the depth in the tweeter and woofer (I bypassed the shunt remember). Now the tweeter still don't sound as good as a straight S.C.R. cap, but it sure did improve everything over the stock the polyesters in the crossover ( 3 in the high pass and 2 in the low pass). (subject was an XT-Vifa tweeter & B&W 7" driver)

I had made the mistake of trying the Bennic made Dayon precision caps.
These turds sucked the life out of my d27tg-45-06. Not the best but a damn good and flat tweeter, especially when you put wool in the pole and use high end caps. ( It has wool in the chamber). This was a fourth order crossover....To say I was dissapointed is an understatement. I was out right ticked off at the horrible muddy sound and loss of depth... Well after some time working on other stuff.
I revisted that system. I bypassed the the Dayton/Bennic caps with .1uF Vishay... the famous ones I won't name ( gotta keep prices reasonable).
Well some resolution and depth returned to the tweeter. It is not as clean as my XT tweeter, but I doubt anything under $400 and named JBL would (maybe) or it's sisters badge scanspeak. The bypass made a real difference.

Now this is no substitute for good caps in the first place. But if you can't get them, don't know what to buy, or can't make them fit...I high end cap used to bypass a passive crossover will make a difference.....

Warning : I use to be skeptical of bypass caps as I used dayton/bennic film/foils to bypass electrolytics in a Jensen Four...I heard no difference,
and only modded on speaker to compare them. Bypass can not save a really horrible cap, design or driver. But they can help mediocre caps. . . .

have a nice day.. . .
~erick~

A man whose music truly came out of his lived experience:
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I recently discoveredMoode Audio in my quest for multi room distributed music. I'm all setup with 3 Pi4's with the following configuration: Pi4 w/8gb working as the player; Pi4 w/4gb & HifiBerry Dac+ ADC Pro; Pi4 w/2gb & Innomaker PCM5122 Dac. All my music is on a SMB share on my NAS (running on TrueNAS Core).

It all plays as expected and I'm still learning but I'm having 2 issues, one major the other minor.

1) Moode will not play any of my M4A files. I get an error message but I don't know where to starting order to fix the issue. See attached image for error message.

2) Many of the album covers don't show up. What are file size limits (if any) for artwork and will Moode render tiffs as with quite a few of my early rips into iTunes I used tiffs before switching to jpegs.

Hope all this make sense and I would appreciate any advice anyone has to offer. Also, let me know if I need to provide any other info for clarity.

Thanks

I was always under the impression that the lower you go the harder it is to hear distortion. Apparently a new range of subs is out which states otherwise. My thoughts are if you hear distortion at those frequencies you would hear "more" further up. Any thoughts on this?

For Sale: Hypex UCD180LP OEM modules. Used and tested great.

How about $50USD each shipped CONUS? I have three available.

I'm open to any size or age, as long as its in good working order, fairly cheap and it is something I can build an enclosure for to reach 25-30hz at low-med spl.
A bit vague, I know, but I'm open to ideas and I'm on a budget! Maybe someone has something lying around unused.

Salas DCG3 preamp completed and fully functional ready to play. Five input selector. Beautifull sound. €.300 plus shipping

Hello
Is there any way when I play a favorite radio station I have added to favourites to alter the order of play.
When I select a favorite to play I am asked: add to end, play next, or play. I would like to alter the order to at least
start with play first of all.
It may seem minor but my remote controls have a limited life and wear out through use regularly.
Help appreciated.
Thanks
thyristor44

What does the Vas compliance measurement correlate to? Most definitions in reference materials I have simply describe Vas as the volume of air that has the same acoustic compliance as the driver suspension. While I understand that a higher Vas means a higher complicance, I've never understood what the number itself means. I just came across this on the Eminence website:

"Vas represents the volume of air that when compressed to one cubic meter exerts the same force as the compliance (Cms) of the suspension in a particular speaker. "

I've seen this version of the definition before, but can't recall where. But I don't understand. I've never seen a driver with a Vas larger than a cubic meter, so you wouldn't be able to compress the Vas volume. Is this definition accurate? If so, are they saying that the vacuum force generated by expanding the Vas (say, 20 litres) to 1000 litres is the same as the amount of force as the compliance of the cone?

Quaint and primitive by today's standards, an interesting window into the past:

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Hi folks,

I have problems with my Marantz SR7000. I really need your help to fix this.

I have this marantz for years now and has been setup for 5.1 home theater system in my living room. It was working nicely until last december.
I disconnected the power source before I went for vacation for about 3 weeks. And when I returned, the unit wont turned on while stanby led is on (red light comes out).

I opened the case and checked the unit and there is no sign of burn or damage. So, I clean the unit and use the hair dryer to get rid of humidity that may have created a problem.

After cleaning and drying, the problem still exist, the remote controller still wont make the power relay to click. I understand that the click of the relay will allow power to main transformer.

Further, I observe one capacitor (470uF/35V) is swelling. It was CB66 in the -30V rail (Vkk). The schematic shows -30V, but measurement with multimeter shows -60V. (I am confused by capacitor CB63 placed in series to 22.3V AC supply from transformer).

The service manual suggest to check this Vkk and FL. The FL, which is 5.1VAC from the transformer is OK. But Vkk is -60V ! And this has drive me crazy, since it supplied from 22.3 VAC through 100uF Capacitor.

I have checked all the capacitor and managed to do this:
1. Replace all suspected caps with new one.
2. Replace 6V regulator IC, 7806 to get 5V supply
3. Replace QB52 transistor, I was suspected this is the culprit. But it is not.
4. Pull out the power relay and check it. It is still good.
5. Replaced 8.2V zener diode at FL rails.

And still not working.

Additional info,
1. This power supply board PB54 is intended to provide 5V, Vkk and Fl to front panel. The Vkk is supplying pulldown voltage (?) VEE to FL driver IC which is mpd16311.
2. This board also provide 5V to "mother board" at the bottom of casing. Whenever I disconect the supply to motherboard, the power relay is vibrating.

Attached is the schematic. Any help or opinion is appreciated.

Regards,

Javen

Saw them on CL this morning and scratching my head. I understand what a plate choke is but never saw them like this before.

ohmite z 50 RF plate chokes

How might I model the effect on the bass response from placing a 10L 2-way with standard 5" midwoofer right on top of a desk?

so my joemeek JM47 stopped working - when i plug in there is the sound of the phantom power charging then silence - im not an engineer , but im willng to have a go if instructed- i do have a meter, solder iron etc

My first posting on this Forum and as you can probably tell I like my Paralabs.
I bought a pair of LNB Paralab 40s a few months ago and have enjoyed them greatly,
They are 3 way speakers with 8" Bass, Celestion HF1300 and Coles 4001. As far as I can tell at the moment the two high frequency units are 15/16 Ohm, and the crossover is fairly basic. I thought thre bass units were KEF but I am thinking they may me Dalesford.
I would love to find more info on these speakers and any mods that people may have carried out.
I have seen many comments on the various LNB speakers and I have a small collection of LNB reviews from a HIFI magazine but nothing, yet for the 40s, can you help?

I have a little 6 channel amp I purchased for speaker testing. I had some trouble with my measurements when using channel 2 and finally realized that the positive output of channel 2 is grounded. On channel 1 the negative output is grounded. this caused some trouble with my measurement probes which connected the grounds together. The amp got very hot.

This seems very weird to me. Wouldn’t that mean that channel 1 is inverted from channel 2?

The manual for the amp states that channel 1 and 2 can be bridged by connecting speaker positive to ch 1 positive and speaker negative to ch 2 negative.

Amp is ”hsf 6CHAMP” made by BSG Laboratories Prolly out of business now. I purchased it years ago off EBay.

your comments are appreciated

Bruel & Kiel dB meter . €.20

Sell a pair of Fab 4312 non inverting module full populated component

on board is mount a opamp LME 9710 ,, also pin mounted for Pro opamp like Sparko pro

https://fabmodules.com/fab4312-non-inverting-amplifier-modules-ready-for-shipping/

newer used Sell for 65 euro

This is the D3a that we have experimented with excellent result. Very natural sounding, finite details.

Hi all!
Are there any owners of these audio pro evo 30 speakers?
Interested inside, speakers, panel thickness, maybe someone hid, repaired?

This is my last resort!

I have a BIC V1020 powered Sub-Woofer that blows fuses.
In searching for schematics and info, I find that the power supply pcb is by indigo which provided this pcb to BASH, as well as the unit supplied by Gateway.

Without schematics, I am isolating circuit flow by removing components. This is not the best way, so that is the reason I am here.

Can someone help me? Direct info is good as well as a pcb schematic.

Thank you,

Dick
Phelan, CA

Listing a beatiful sounding ECL-86 / 6GW8 amplifier. The ECL-86 is an amazing dissimilar driver / pentonde in one envelope and in this circuit (my own design) is phenomal and generates about 3 watts. The other key to this amps sound is the Type 80 / 280 rectifier. If you've never heard this type rectifer you are in for a real treat.

The entire signal chain from within the amp begins with the rectifier and if you don't believe me just swap in different types in this amp: coke bottle vs globe and hear the difference. Why? it's because the B+ will change due to the efficiency of the rectifier type.

I build these amps from scratch and you can find my ad US Audio Mart for my service and as you can see there's no rats nest inside of this amplifier and the amp is dead quiet (no easy feat with this tube type).


You will get:

1. One (1) Amplifer
2. A Matched set of ECL-86s (Amperex, tested strong)
3. Philco Type 280 Globe (tested strong)

$475 plus shipping (I can ship worldwide: I have shipped all over the world, send me your zip / postal code and I will get you a quote)

No power cord.

Cheers,

Greg

ALL SOLD

01A THORIATED TUNGSTEN Filament TRIODE TUBES

Tubes come in generic white tube boxes with testing data on box. Price listed next to each set.

All Globe tubes, varying degree of light microphonics, as all globe tubes I used.
eTracer New Test Values: gm = 800, Ip = 3.0 mA (135 plate volts, -9v bias)
TV-2 minimum value is 18

Shipping to be decided at time of sale, I will combine shipping.

Tubes are clean and pins cleaned as well.


SOLD SET #1 Commander 01A, hot stamped bases $50/set SOLD

#004 766 2.99 32/18
#007 752 2.45 31/18
#008 711 2.12 40/18

SOLD SET #2 RCA Radiotron UX-201-A hot stamped bases $35/set SOLD

#013 720 2.43 (Hickok test 700gm, 2.6mA)
#016 754 2.57 (Hickok test 700gm, 2.6mA)

SOLD SET #3 Cunningham CX-301-A hot stamped bases $50/set SOLD

#003 837 3.91 37/18
#010 855 3.95 38/18
#009 833 3.11 38/18

SOLD SET #4 Cunningham CX-301-A hot stamped bases $35/set SOLD

#011 887 3.66 38/18
#012 927 3.62 40/18

SOLD SET #5 Radiotron UX-201-A hot stamped bases, $35/set SOLD

#005 690 2.55
#006 712 2.87

SOLD Set #6 Radiotron UX-201-A hot stamped bases, $35/set SOLD

#015 756 3.04
#014 717 2.29

JBL 2307 PAIR CONICAL HORN PRO VERSION OF THE HL91, €.150+shipping

I'm looking for a new mid-range scope, 2Ch, 2GSa/s would be about right with 200-300Mhz bandwidth. I'm looking at the Rigol DS2302 and the Siglent SD2352.

Anyone around that can 'clue me in' on the Siglent over the older Rigol.

Thanks, Dave

Hey everyone, happy weekend!

So I picked up a pair of working Acoustat Spectra 1100s at an estate sale for $425. They look pretty good and sound decent. I've always wanted to experiment with electrostats so here is my chance. These things are big! Anyway....underwhelmed so far. I don't really have an amp that can drive them well yet - running on a Pass DIY Zen v4 right now. Totally not the best match lol. The previous owner was running them with an Adcom GFA-555 Mk II. I think the panels have potential with some fresh modern caps, a strong amp and more placement tweaking. Was wondering how much that step-up transformer colors the sound. The bass though needs a lot work.

Two questions/observations:
1. The treble on one side is quieter than the other and the problem follows the crossover box. Nothing looks bad on the crossover boards, and while I did not measure anything yet, I am starting with the assumption it could just be related to 30 year old caps beginning to wear out.

2. Most importantly right now. The bass is overblown! Noticeably way too loud and boomy. The drivers match pictures online, so I am assuming they are the correct units. Still though, the bass does not integrate well with the sound from the panels. Whether the speakers are 3 ft from the back wall or 11 ft from any wall in the middle of my basement, the bass is just too loud and thick. I noticed the woofer boxes are stuffed with polyfill....was thinking I could removed some and see if the sound at least tightens up.

What are you thoughts on this, especially the bass response.

Side note: They claim these are 8" woofers, but they measure nearly identical to the 7" in my Energy Pro 22 Reference Connoisseurs. They look like 7" too. They sound like subwoofers more than woofers.

Since I was a teenager, and because we didn't have a lot of money, I always bought or salvaged broken things, so and therefore, with the experience of years, I repair absolutely everything except humans and animals and I buy less than one new device per year (not even ...)
So I have little or no failure, but it happens and I'm interested in knowing what's going on with you and ESPECIALLY sharing experiences of failure or success.

I’m looking for some of these drivers. Let me know if you have some for sale.

I have this amp. It was working before. Now if I switch it on, the led is flashing red and green. Checked everything, amp is OK. Also the output stage is oscillating. But it blocks the audio input to the irs.. I found, that at the ps, the caps towards the ps fets are missing, broken of.. Any suggestions for the uf of the caps I can use? Expect, that this missing caps are disturbing the undervoltage protection or something else.

Moderation edit... thread split from here:
https://www.diyaudio.com/community/...ormance-cmos-audio-op-amp.335416/post-7084083

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I understand, but it is not for the direct audio circuit. Its in the servo and should be OK for that.
The 1642 is unobtanium (SOIC08).
You have some for sale? ;-)

Jan

NLA!

can this driver be horned?
what size horn it should be?
i have no pc,only handphone,so i can't run any horn program

who knows this Spain music's name?

Thanks,

I plan to build an passive attenuator to step down multiple identical audio sources (Class D amplifiers rated 3W@4-32 Ohms) to multiple sound card inputs +4dBu (MOTU 2408 MKII duplex sound card). Each source will go to a dedicated input channel on the MOTU sound card and thus it is my understanding this creates challenges due to summing of differential Class D voltages (compared to just a single source). The goal is to preserve sound quality as reasonably as possible and as tactile transducers rate to 12 Hz will be used, maintain source bass signals below 20 Hz. Also, the source signals will be summed in a VST host in various combinations (e.g., 3 sources may be summed to 1 output channel with another 2 sources into a different output channel). As electronic circuits are not my strength, I have multiple newbie questions:

1. The source volume can be adjusted. However, the listening volume will always be adjusted after the sound card. What level should the source volume be set at to maximize sound quality (S/N ratio/distortion)? I assume maximum volume, but perhaps when considering the interaction with the passive attenuator, a lower source output may be appropriate. Also, as the sources are Class D amps, perhaps there is an optimal volume level which has less distortion. It seems determining the volume level is important as it will change the attenuationl level needed and the component values (e.g., resistor Ohms rating).

2. What type of passive attenuator is ideal for this application? As bass/subsonic signals are desired, audio transformers are not ideal due to bass frequency loss and the cost of quality audio transformers which preserve bass signals is prohibitive with planned channel expansion (up to 40 mono sources). Thus, it seems that voltage dividers/"pads" such as L-Pads, Pi-pads, T-pads, etc. are the ideal solution considering compromises of cost vs. sound quality. However, in reading about the various voltage divider configurations, it is not obvious which voltage divider designs are suited for which applications, particularly this one.

3. Related to question #2 above, the impedance of the source and sound card are likely mismatched (I'm struggling to relate the amp Watts output to sound card dBu input). Some authors mention the voltage divider source and output impedances can be matched, but not for both impedances. Does this matter in an audio application? If so, then it seems some voltage divider arrangements are not appropriate and only designs in which the impedances are matched both directions should be used.

4. Some voltage dividers are unbalanced while others are balanced. Is either unbalanced or balanced preferred for audio applications?

5. Does the "balanced" aspect of a balanced voltage divider have any relation to "balanced" audio signals (e.g., XLR cables)? Edit: I forgot to mention that the Motu can receive a balanced (1/4" TRS plug) or unbalanced signal (1/4" TS plug).

6. The MOTU 2408 MKII sound card is DC coupled which may cause a DC offset. While I understand how the value of a DC blocking capacitor is determined [Xc(ohms) = 1/(2*3.14*f*C)], it is not clear where the capacitor should be place in a voltage divider. Does it matter if it is placed before or after R1 (or somewhere else)?

7. As the Class D amplifier sources have an unknown high switching frequency, should a low pass filter also be added to the voltage dividers? If so, it is not clear where the capacitor should go in a voltage divider. Does it matter if it is placed before or after R1 (or somewhere else)?

I try to learn as much as possible before posting, but as after many hours of studying, I'm not making much progress. It seems that much of audio involves rules of thumb known by those in the art and many educational articles do not directly related to audio or sound quality. Attached is the project with the areas of concern in red.

Im planning on building the kongo horns for my small studio and have couple of questions-

1. What other drivers could be used for this design? Im hoping for something cheaper that i could buy from partsexpress.

2. Is the plan available in metric system too? I worry that im messing up the dimensions by only roughly following the metric units already on the document

Hi all, Its been around few years since I've posted here and I'm hoping some much more knowledgeable members can once again give me guidance.

I have a valve PA amp that's been sitting collecting dust and finally opened it up, There's no circuit diagram available so I will have to trace this out, I have no problems with everything after the rectifier circuit, However, The rectifier circuit does have me bemused.

I'm not an electronics tech, But I do have a very healthy respect for high voltage, The amp has 5 valves, 1 x EF86, 2 x 12AX7, 2 x EL34, I believe the rectifier circuit may be half wave? 'but its how the diodes are connected that has me confused' (I've attached a photo).

The AC input of neutral active & earth are not a problem, However, The Yellow wires in the photo are the high voltage secondary's with the green CT below the yellow wires soldered directly to ground.

One side of the high voltage secondary appears to be connected correctly through one diode to the first filter cap. The other half of the high voltage secondary is connected directly to the second pin of the first filter cap, The second diode has one leg connected directly to ground with the other leg connected to the first HV secondary mentioned above?

I can't wrap my head around this as to whether the rectifier circuit is a half wave or full wave rectifier circuit. The other colour wires coming out of the chassis are Blue = 6.3v heater, Green = CT for HV secondary, Brown = 240v mains in.

I've attached a photo of how the circuit is soldered in question

So my questions are

1 - Is the rectifier circuit half wave or full wave?

2 - How do I draw this out for schematic purposes, as I'm a bit dumbfounded by it?

other notes: I've not powered the amp up nor made any changes except cleaning off the build up of cobwebs and dust.

I hope someone can give me advice and guidance with this project.

cheers.

Hi,

I watched a video today from Thomas and Stereo on Youtube and he mentioned something about transformers that I don't understand.

He said that regular transformers have more punch than toroidal transformers. I'm a beginner hobbyist but want to know other opinions.

Do toroidal transformers make music less "punchy" than regular transformers?

Thanks,

Dan.

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I’m looking for a schematic for the KAV-250 and have come up empty handed. I did see a post from 2007 with a hand drawn schematic of the output board. That helps. But really need the driver board schematic. I have one channel that starts making static/popcorn sounds the second I power up the amp. I can see the noise on my scope right at the input of the amp as well as the output. Very hard to isolate. Any suggestions would be great.

Hi,
I Bought an amp that have just had the output transformer replaced. The owner said she used it once fine and then it started blowing fuses.
I set up a current limiter and everything started up fine after five minutes of playing without the limiter I got blue sparks through one of the power tubes and the slow blow fuse blew.

The PT and the OT are not original. I have sketch out the power supply So not sure of which windings are connected Because I haven’t disconnected.

I research as much as possible to could be bad tube Or loose socket Or poor OT connection or Intermittent voice coil problem.

*I notice when taking readings with no power tubes pin3 Create scratching sound in speaker.

*I test for vac on bias circuit. noticed 22 vac On negative bias Circuit Close to diode Then no vac 10mm up circuit futher , Only the -40vdc negative dc bias.

*I question the power supply. original schem. has a lot higher voltage730v vs 495vdc to OT primary centre tap (ht1 on schematic) than amp has now.

*the two 220k resistors Jumping the filter caps straight after the rectifier.

Any advice what to check for would be great thanks.

I have a pair spare El34, do not want to put them in in case the problem could be not just bad tube.

I will upload the schematics now, thanks

"The Wire" Official Boards for All Projects Available Here! BAL-BAL, SE-SE, LPUHP

Hi Gentlemen,

Well, it has been a long wait (a very long wait for some of you) but all of my PCB’s from “The Wire” series have been updated and will be offered on a full time basis rather than on a limited run basis as they have been in the past.

This thread is going to cover the transition period between now (another Google Spreadsheet based order system) and the eventual launch of the website that will have a store where these can be purchased.

Over the next two weeks I’d like to get an idea of demand for each of the boards so I can place an order and panelize it accordingly. I will then place the board orders which will take 3 weeks to arrive at my doorstep. After that, I will need a week for testing, and then I will ship the first wave out and start taking real-time orders from then on while hopefully maintaining a proper stock of boards. Hopefully the website will be up and running not too long after I start taking real-time orders.

Please use the following Google Spreadsheet to place your orders:

the wire pcb order form - Google Sheets

What follows is the description and pricing for each of the boards that will be on offer. Pricing is slightly higher than before, but you’ll be getting better boards (modified to take advantage of all 4 layers) and ENIG immersion gold plating with tented vias for better solderability. Pricing is also more in-line with the actual surface area of the board, so smaller boards will see almost no price increase, while larger boards will see more of a price increase.

Without further ado:

“The Wire” BAL-BAL Headphone Amp ($17 for a single stereo board)
- Design altered slightly to include a 4th layer GND plane.
- 4 Layer PCB – 1oz copper – immersion gold plated – tented vias – white soldermask
- Improved headphone connection points
- Overall same size as predecessor
- Same schematic and BOM as predecessor
- See project thread here: http://www.diyaudio.com/forums/head...igh-performance-headphone-amplifier-pcbs.html
- See project wiki here: The Wire - All Boards and Kits Explained Here!

“The Wire” SE-SE Headphone Amp ($15 for a single stereo board)
- Design altered slightly to include a 4th layer GND plane.
- 4 Layer PCB – 1oz copper – immersion gold plated – tented vias – white soldermask
- Floating GND connection fixed
- Overall same size as predecessor
- Same schematic and BOM as predecessor
- See project thread here: http://www.diyaudio.com/forums/head...igh-performance-headphone-amplifier-pcbs.html
- See project wiki here: The Wire - All Boards and Kits Explained Here!

“The Wire” PSU for Headphone Amps ($15 for a single PSU board)
- 4 Layer PCB – 1oz copper – immersion gold plated – tented vias – white soldermask
- Slightly wider than predecessor
- Completely redesigned using dual TPS7A3301 (TO-220) ultra-low noise regulators.
- Now requires a transformer with dual secondaries. Centre tapped transformers will not work.
- Significant performance improvement from previous LM317/337 regulators.
- See new BOM here: https://docs.google.com/spreadsheet/ccc?key=0AnMLwB9mdXl2dDN6V05FanpQN1BFR2xRcENORVFSNXc&usp=sharing
- See new schematic here: https://drive.google.com/file/d/0B3MLwB9mdXl2Z3N4WWh4MU93SW8/edit?usp=sharing
- See project wiki here: The Wire - All Boards and Kits Explained Here!

“The Wire” LPUHP Amplifier ($28 for a single channel board)
- Design altered to include a 4th layer.
- Thermal vias added to allow simple heatsinking from bottom of PCB.
- 4 Layer PCB – 1oz copper – immersion gold plated – tented vias – white soldermask
- Transformer moved off-board for lower noise and compatibility with 120V/230V
- Regulator sections changed to use dual LT1185 low noise regulators.
- Measurable improvement in performance – noise floor is nearly 10dB better.
- See project thread here: http://www.diyaudio.com/forums/soli...gh-perfromance-lpuhp-16w-power-amplifier.html
- See new BOM here: https://docs.google.com/spreadsheet/ccc?key=0AnMLwB9mdXl2dDVuTjh6WnZmQ1VxYm1FVW9zRzRaMUE&usp=sharing
- See new schematic here: https://drive.google.com/file/d/0B3MLwB9mdXl2TnQ0Wjd2UUFMcDQ/edit?usp=sharing
- See project wiki here: The Wire - All Boards and Kits Explained Here!

“The Wire” LME49830 Lateral FET Power Amplifier ($17 for a single channel board)
- Design altered to include a 4th layer.
- 4 Layer PCB – 1oz copper – immersion gold plated – tented vias – white soldermask
- Identical to predecessor
- See project thread here: "The Wire AMP" Class A/AB Power Amplifier based on the LME49830 with Lateral Mosfets
- See assembly manual here: https://drive.google.com/file/d/0B3MLwB9mdXl2NVEwS1pwNVV0OG8/edit?usp=sharing
- See project wiki here: The Wire - All Boards and Kits Explained Here!

NTD1 PCB V3 - ($35 for a single stereo board with full PSU)
- 2 Layer PCB – 1oz copper – immersion gold plated – tented vias – white soldermask
- Designed to be used with BII, BIII and ACKO ESS9018 based DAC boards.
- Upgraded TPS7A3301 regulator section – Improved noise floor
- Same dimensions and mounting points as V2
- See project thread here: http://www.diyaudio.com/forums/digital-line-level/154866-new-take-classic-pass-labs-d1-ess-dac.html
- See project wiki here: The Wire - All Boards and Kits Explained Here!

Upcoming Boards:
- Behringer DCX2496 Upgrade Board - Digital, Analog, Clock and PSU sections.
- UHPSR - Ultra High Performance Shunt Regulator - Adjustable 1.1V to 5V
- HiFiduino all in one PCB – Arduino based controller and all peripherals on one PCB
- TPS7A4700 / TPS7A3301 Regulator PCB – LM fixed reg drop-in replacement

More info to follow, and the spreadsheet link will be posted in a few hours!

Cheers,
Owen

I'm building a BR using Ampslab's recommended 25 liter enclosure with the Silver Flute W20RC38-08. He calls for a
2" diameter port 6 1/2" in length. My cabinet will be 9" deep or 7.5" internal. To leave plenty of clearance from the back wall can I use two 3 1/4" ports and accomplish what I need to? Thanks for any suggestions.

Hi all.

I am in the process of designing my own fully symmetric bench power supply. It will go from 0 to around ± 70V @ 3 amps.
The voltage controls will be floating, while the current limiters probably will be in respect to true gnd of the main supply.

The whole thing will consist of 4 internal supplies to make it all work. 1x 75-0-75 and 3x 15-0-15 DC. One of the 15-0-15 will share gnd with the
75-0-75 main supply. The two others will be floating, which is where I am a bit lost.

I cant wrap my head around to to make the tracking work between the two floating supplies. The only thing I can think of is to
create some variable current sources in the common 15-0-15 supply, and pull that current through a resistor in the floating
supplies. That should work, but it somehow doesnt feel right.

I dont need mcu control or programmability. I just want to turn one reference voltage from true gnd into the same voltage on
each floating supply. I have thought about using a stereo pot for this, but the channels usually dont track too well on pots.

I also havent found any info on this, nor could I find any schematics on this issue.
Any insight on this is welcome

Thanks in advance
Jørgen

Monitor Audio Silver 6 G5 crossover

Hi all,

I am just wondering if it make sense to upgrade the crossover of MA silver 6 G5 (to make the speakers level up), or did anyone here did some mod...or I should just leave it like it is... here is a pic of the crossover