I apologize upfront for what may be a dumb question.

I have a PCB for a Pass Aleph 1.7 preamp. It is balanced input to balanced output. I don't run balanced gear. I know I can use it as designed to accept single ended input and output single ended, but am wondering if I can convert it to just single ended operation.

Attached is the schematic. Would it be as simple as just populating the left side of the schematic and using "+IN" and Gnd for the input and "-Out" and Gnd as the output? I realize this would invert the signal.

Thanks for your thoughts.

I have a pair of T20U now (anyone remember these)? Great amps but only about 7 clean wpc into 8 ohms. Apprently you can bi-amp these (I have the separate Kingrex Pre-amp, too). The owners manual doesn't say how it can be done, but it's been done. Anyone know how I can bi-amp these?

I have an Army of Iron for sale: 4 counts of Hammond 193R chokes, 4 counts of Hammond 193U chokes, 4 Antek AS-2T230, 2 counts of Hammond 193A, 200H plate chokes, and 2 Silk grid chokes... all in the amp pictured, not to mention separate power supplies for each tube and the collection of poly chokes within. I am entertaining offers. Of course the entire amp is up for sale if you'd like. Come see me at Chums Corners just outside of Traverse City Michigan. I have several amps and much back stock that I must part with.

Article in the June issue of AudioXpress "Evaluation of Automotive Energy Efficiency" by Phillip Paul Klose.

The losses in the audio system would seem trivially small compared to moving the vehicle.

New to this forum.....hi to you all.
Never really dabbled with hi-fi fault-finding/fixing, just wanted to get that out there 🙂
Recently collected a free set of Gale Gold monitor mk1 bookshelf speakers which came along with an amp I was after. Having read the reviews for these speakers the suggestion is that they are decent budget speakers, let down by wayward treble. Connected them up (bi-wired) to a Cambridge audio a300 amp today and they definitely lack sparkle. At low volume I put an ear to each of the tweeters in turn and swear I could detect very little coming from the left, and nothing from the right. LF drivers seem fine. Disconnected tweeters and both had a resistance of approx 6ohms. Then went to look at resistor and capacitor for each tweeter. I don't have a dedicated meter to measure capacitors, however on the ohm scale the left speaker cap started at approx 10megaohms, then climbed steadily. On the right speaker the cap started at 30megaohms then climbed steadily, although did go open circuit on one measurement attempt.
Duff cap/s perhaps?
Has anyone upgraded the tweeters/resistors/capacitors on Gale Gold Monitors to a successful outcome? If so, which components did you use?
The reviews would appear to bear some truth about HF being wayward but I'm unsure if that's what I'm experiencing, or if I have other issues with the capacitors.
Should I replace the caps, and if so which would you recommend? If you have upgraded to better the treble and bring it better into sonic control, I would be grateful if you could share the detail please.
I'm handy enough with a soldering iron and multi-meter, so, happy to have a go at fixing/upgrading as necessary.
Thanks in advance for any advice you can offer.

I'm cleaning up and sell all the parts I collected in the past for projects that never left prototype state....

2 custom OPTs Parallel PP 2K2 4-8 Ohm 40% ultra linear taps,C-Core, 140 W, case 3,
very low capacitance with 18 chambers!! THE OPTs ARE SOLD!
4Ω 3.4 Hz - 102 kHz -3dB
8Ω 3.4 Hz - 79 kHz -3dB
Square wave response 10kHz : excellent
Distributed capacitance
Fres grounded 8,8kHz 1760 pF
Fres floating 18kHz 412 pF
induction L = 180 H (quality cores)
leakage induction 4.0 mH

600,00€ the pair(cost far more than twice that much when I bought them, today even more expensive),
since they are very heavy, shipping has to be calculated



2 custom chokes 4H 450mA, THE CHOKES ARE SOLD!
C-Core, 20Hz sat at full power and >100 kHz bandwidth,
Max AC saturation 640V 100Hz
Saturation without AC flux across the choke will set in at 0.81A
common mode operation on dual bobbin, low stray capacitance,
13 Ohms per winding = 27 Ohms in operation

Anyone know where I can get or fab an accelerometer (plastic-tape??) for enclosure analysis?

Hi everyone,

As part of my ongoing project (making a DAC) I have finally got to the output stage. Not only the output stage but the filtering of the output stage!!

Anyway, enough celebrations. I need a ~30mH inductor for use in my filter. I know it seems big, but that is due to its location, which is right at the end of the output stage, right before the final buffer.

Question is:

1) Where can I buy such an inductor?
2) How can I make an high value inductor like that?

I know that Solen make a nice 30mH inductor which is expensive $35US! and very big...because it is aircored. I've also found some sites that contain information allowing the design of aircore inductors. Has anyone here made their own? What is a practical way to do it? How long does it take? Would it be OK to use a metal cored inductor here? Circuit is posted below for information:

One pair of verry good coax drivers for sale with verry good crossovers. They are about a year old but in like new condition. I have original box for this. Price is 400 euro including crossovers pkus shipping inside EU for about 40-50euro.payment thru paypal. More info on PM.

Brand new and never used!
Solen sells them for $350 USD each; i'll sell them for $600 USD for the pair plus shipping and 2.9% PP fee.

I'll ship internationally at full cost to buyer. Please don't ask me to undervalue these on a customs declaration.



BLIESMA T34A-4, Aluminum/Magnesium 34mm Dome Tweeter. 96db, 4ohm.

Good morning allerseits 🙂

I'm on the lookout for audio-transformers (input), found some, but don't know how to interpret it.

The impedances are stated as (@ hammond)

106E = primary: 600 ct / secondary 600
106EE = primary: 600 ct / secondary 600 ct

So this seems to be of a certain significance. Does it mean Center-Tap?

Thank you!
david

Hello all. I am new to posting here... I need some help with information on the little ceramic preamp board in the KAC-821 .. turns out when you clean this board with 99% isopropyl alcohol, it removes the resistor and tinned contacts and makes thing go poof... I have the service manual for this amp and I am able to translate where the preamp integrated with the rest of the amplifier. But am up to suggestions on building my own board for a successful repair.

Thanks for your time!
-Kevin

Hi

I just built, what I was thinking to be, a very simple dual 5v linear regulated power supply, to power a rpi-4 and a hat with a digital audio out. I'm running ropieeXL.

The transformer is rated 230v to 2x24v 30VA ( https://www.audiophonics.fr/en/toroidal-transformers/toroidal-transformer-30va-2x24v-p-5649.html ) feeding two LT1084 1.2V / 19.5V 2.5A regulated linear power supply modules ( https://www.audiophonics.fr/en/diy-...th-heat-slug-lt1084-12v-195v-25a-p-11645.html ).

I measured the voltage AC out of the transformer is 24v on both secondery outs, and the output voltage out of the linear power supply module is 5,01v and 5,03v DC on each side. The rpi-4 and the hat lights turn on when I power everything but nothing happen, the rpi-4 lights blink as usual but ropiee never realy starts up, so I checked the current being send to the Board and I get 0.035 amps which may explain why it's not working at all. Voltage still read 5v.

I can't understand why this is happening... is it possible that I wired something wrong ? The boards work because I just connected them to a cheap switch power supply and I can run rupiee and stream music with no issues at all.

I admit I'm totally newbie and probably shouldn't be playing with power supplies, it can really be user error, but I would really appreciate some help 🙂

Thx in advance
Nuno

Hello! So,I want to build a tapped horn for home theater but I dont know how to fold it.Ive seen that many people do it in a 3d modelling software but I dont know how to use any of them.So is there an easier method,like a software or website where I insert the values that hornresp got me and it will calculate and fold me the horn? Also,would this be a good one? The driver is a Dayton Audio DCS305-4. Thanks!

Hi, I have 4 pc’s. Fostex 6301b, which I am very happy with.
Now I want to use them in my 7.2 surround amplifier.
BUT: How do I Connect them to my receiver? There are only loudspeaker output for all the speakers. Front L+R, Center and subwoofer are without Amplifier, so there is no problem. I Can of course modifie the recieve and take the signal “before” it end in the poweramp. But it is a heavy job.
Is there a better solution which is easier.??
Thank you
Rgds

Lars Helsboel
Denmark

Hi.
Well made tube power amplifer with 4 EL519 output tubes. One channel is playing with less volume. Cant figure out what is problem. Attached oscilloscope photo. Input signal generator with identical voltage. Changed tubes from one channel to another, no change. Input to first tube grille identical. Voltage to output transformer is different. It is about 26 years old. Attached photo from inside also.
Hoping somebody with more experience can give ideas what to check.
Thanks advance!

hi, I have a Rogers Panthera amplifier. I can't find its schematic diagram. I'd like to know the millivolts and bias quiescent current of the four fine adjustments at the back of this machine. I need your help. Thank you,

Hi Guys,

I am looking for KSC3503E to match with my KSA1381ESTU

If someone can provide me with a few of them, please send me PM

Many thanks
Theo

So far everyone has been stumped and I thought this would be a good place to ask. Here's my original post on another forum:

So I finally decided to try out the Raytheon 6V6GT/G and Holland Amperex 12AX7's I have. I was already using the same 12AX7 tubes, I just wanted to test these out. I took all the tubes out and dusted off the preamp chassis and tube tops. I then put all the tubes back in using the new ones. I turned on the preamp and then POP! out of the speakers, this happened maybe two seconds after I fired it up. Startled the crap out of me. I VERY quickly turned the preamp off. I noticed that the Ratheon 6V6GT/G slowly lit up after I turned on the preamp up until the bang/pop where it got brighter much quicker. What's the deal here? The Raytheon tested better than NOS on the sellers tester. I put the RCA 6V6GT back in and all is well, the preamp is fine and all eight tweeters are fine. The Raytheon has an extra pin that the RCA does NOT have.

I took this picture zoomed in too far to be holding the camera, I can't stay still enough for a crisp picture at this much zoom. The RCA is on the right, Raytheon on the left.

Click to expand...

Now, the issue is either something happened to the tube during transit or another guess was:

I 100% don't know (sorry), but sometimes tubes have an "extra" pin -- and sometimes it can cause a problem IF a component manufacture happened to use that pin's location on the socket as a "tie point" for other circuit components. It's an admonition one will see sometimes in the tube manuals.

Click to expand...

I emailed my tube preamp manufacturer (Dared MC-7P) to see if there would be an issue running a 7 pin 6V6GT/G instead of a 6 pin 6V6GT but they have not gotten back to me so far.

I do have a schematic for my preamp but aside from seeing where the 6V6 is in the power section of the schematic, I have no idea what I'm looking at.





Any ideas?

Ik buyed FilmCaps brand ClarityCap:
4x PWA 100uF/160v
2x PWA 47uF/160v
2x PWA 33uF/160v

The wires of the 47uF and 33uF are nice clean and shiny.
But the 100uF looks like they were heated and then coated with some kind of 2-comp resin, and dryed later.

Look at the pictures.
Should i be worry about something??

A set 2-way Audio Note loudspeakers came with a set of double coax cables for each channel. So, a separate coax cable for signal and return.
See attached picture.
Can you please think aloud - or even talk from experience - on why this may be useful?

Please, PLEASE no flame on that cables do not matter.

FS: Bang-Olufsen (B&O) ICEpower 500/1000ASP, 250/500/1000A D-Class Amplifier Modules

Sold

This Ultra Analog UA 20400A DAC chip was pulled from an operational Audio Research DAC 2 digital to analog converter.

I subscribe to the '15 song album' and 'DML' forums, and about every 2 weeks, I do not get the update emails for one or both of these forums. They are not in my spam box.

Hello
Unit worked until passed voltage to mic handle in channel 2 then no signal would pass thru channels 2 to 8 to monitors or headphones. Problem is hardware as no compu is connected. No schematic available from Tascam. Unit is outside of USA repair by Authorized dealer is automatically replacing the entire board. Price equal to new unit. Any suggestions?

I want to share some comments about an experience I´m doing.

I´m doing an EL34 class A UL toroidal output transformer, based on some readings from Menno van der Been, but made of my own. I had done the following try: I buy 3 commercial illumination toroidal transformers, 220V to 12V 25Amper, the biggest I could find. I measured all parameters before unwind, primary resistance, inductance, leakage inductance, etc. So, I unwind two of them, and measured turns, core dimensions, so I could estimate core parameters as, power capacity, inductions, etc.

I done a new winding re-calculating the new cutoff frequency based on induction, cross sectional area, peak voltage between plates, etc. I hand wind equally spread around the core, and in 7 turns one over the others to complete circumference of the transformers, but something was wrong. About 8KHz, the -3dB I could find. The windings are done bifilar about 1000 turns between screens taps, and 1500 more from tabs to plate, a total 40% voltage ratio for screen. I believe that winding in such way, the total capacitance inter-winding is too high. So, I´ll try another form. I want to subdivide the circumference in 10 sectors, separate them by a spacer, and wound single wire in each section. In this way I can have the total 3000 turns in sectors phisically isolated, and capacity must be lower. Two sections will be for the screens (600T) and 3 sections more for the plates (600T +900T = 1500T).

Any suggestions or ideas are welcomed.

Hey guys

I have a pair or ML Aerius I ESLs that I recently had apart for cleaning and capacitor replacement. I hadn't put the lower mesh grills back on yet and last night my cat decided to use one of the woofers as a scratching post.

Would anyone be able to assist me in choosing a set of suitable replacements? To make life a bit easier I'm going to be running the bass section off a Crown pro amp with DSP. I could likely send the stock woofers to Solen and they'd be able to do something for me but I thought the smart people in here might have a few suggestions.

I'll pull the woofer out of the cabinet tonight and grab some pics. It's not completely destroyed but it definitely looks like hell.

Thanks guys

I'm curious if anyone has any experience with the Volume input Control Boards on ebay from China

Such as

https://www.ebay.com/itm/353052625002?var=622242443310

For the price same price it seems it would be too make the equivalent?

Hi everyone, I'm looking for information about these drivers and need help to understand if can be used to replace Acoustic Research AR12s midrange drivers (that has 700-4000 xover cuts).

Thanks in advice to anyone that can/would help.

Which of this bipolar is the best?

Hi. First post. I purchased a pair of martin logan aerius speakers which were sold as having outstanding sound. After paying over 550. for safe,fast shipment. I received a pair of huge boxes for each packaged by ups store and delivered in 2 days . The boxes contained no padding other than 1 layer of bubble wrap but tons of room to bounce around in transit. The seller said that the no sound situation from 1 was probably loose or broken wire. I switched panels, transformers, and then finally the circuit boards where the problem was discovered. One works, one doesn't but both show signs of contact heat blistering under an as of yet identified component which is purpose of my rant and post. Could someone please identify component on circuit board with zip tie around it.and where might it be purchased.. Pic enclosed

I am very interested to understand form an overview perspective, clocks, noise and performance, how the different clocks affect and potentially compromise the performance in the video chain

My set up is Panasonic 9000 4K player (with LPS) this has two (evidently better than average clocks) one main board, one output HDMI, then this goes to a Lumagen 4242 this has three clocks, HDMI input board, main board and HDMI output board, then this goes to a projector (epson LS10,500), which I assume has one or two more clocks

I found improving the power supply in the 9000 with a Coris LPS improved the picture, I have also upon recommendation added three very low noise/jitter clocks to the Lumagen and found quite a signifiant picture upgrade, so wondering where I might still be leaving something on the table.

Any insight appreciated

Due to some changes at home, I have absolutely no space for them and that's the why I have to sell the best (and biggest) speakers I have ever had.
To simplify things, I'm selling all the drivers (unless 18" woofers) and all the original populated crossovers (TL1 or TL2 crossovers can be choosen).
All the things to be sold were bought brand new and they have no more than 100 hours of use. In fact maybe less that 70 hours.

I'm sorry but I cannot split anything not share crosover schemas or values. Please, do not ask.

For sale:
2x Fostek FT96H Super Tweeter
2x 18 Sound compression driver NSD1095N 8 Ohm
2x 18 Sound horn XT1086
2x 18 Sound midrange driver 10NMBA520

Crossover for Super tweeter+tweeter section. Original Values
Crosover for midrange section. Original Values
Crossover for Bass section. Original values but no LCR equalisation circuit for 18" woofer (not needed)

Crossovers were built with original values and fits Jantzen audio components:
Z-Superior Caps for Tweeter and super tweeter, cross cap at the begining of midrange and Z-Standard for every other cap in the crossover.
For bass section Elko Superior were choosen.

All the coils are oversized air core coils unless iron cored with discs 1,4mm at woofer low pass.


I'm asking 2300€ for the whole lot.
I can include, a pair of FaitalPro 18F510H 18" woofers that will work like a direct replace for BMS 18N862 woofers for 250€


PP fees if apply and shiping is not included.

Some pictures:

Announcement!
New DAC product based on the latest ES9038PRO chip!
__________________
AckoDAC Project

I will be running my charging system at 15.5 volts for the audio system .

The battery and alternator are totally isolated from the 12 volt system .

Wondering if I can connect the power wire from the symmetry to the 15.5 volt system ?

I connected it the first time to the 15.5 system and smoked the power supply in the symmetry just wondering if it was a fluke

I have an amp 200W.@4ohms with a sensitivity of 1V,
with feedback resistor values of 27K and 1K , there by making the gain of 28...which is fine but when I connect the amp to speakers I hear a hiss if I go very near to the speakers , can this be avoided if I use lower value resistors say 10K and 370ohms or 5.6K and 207ohms?
I understand that power dissipation can and will be a issue ? What's the way to eliminate this hiss and this only happens when the amp is connected to my PC.

I was using a signal generator to listen to my amp's freq range and determine where the bass seems to roll off. It uses a capacitor coupled output, not a transformer. I am looking to get a few Hz lower rolloff point. I noticed that when down around 5Hz, inaudible, I know, I could see the coronas on the power tubes flicker in time to the cycles, but there was no subsonic movement in the speakers, at the output. Does this mean the rolloff is in the output coupling caps, but that the power tubes are seeing this low frequency? Also, can these ELFs damage the output stage? It seemed that they were making the amp work extra hard, and I think I even noticed a little plate glow, and thought I smelled ozone. Is it possible to produce ozone? I have built a Tesla coil and know well what it smells like. How could a power tube produce this?

I purchased Yamaha P2200 power amp. I already own P2201 (same app minus the VU meters). The P2200 was missing both needles on VU meters, light bulbs are out but the amp is functional. Measured the output and read 23.5mV and 26.7mV on each channel. Not bad.
I started cleaning the amp. Similar to P2201 I have it is has seen a better days. Some previous owner scratched his name and phone number on the bottom and back plates. Perhaps I should call him once a day...
Once I removed the VU meter plate, I noticed that needles on both VU meters are broken. I removed VU meters and discovered the needles. What would be the best way to glue/secure them?

The VU meter on the left side is working but the one on the right side doesn't. Also the bulbs get no power. I have read that cold solder could be the problem with these amps, something to check...

Any advice on repairing the needles is welcomed. I thought of using superglue with baking soda, epoxy, solder (probably bad idea as the insulation on the needle is likely to get damaged once heated), shrink tubing (won't last and needle could be too close to back plate)... I unerstand the added weight likely to affect meters accuracy.

I am looking for a very basic audio streaming device. I know there are bluetooth streamers, Raspberry Pi based solutions, etc. What I need is a simple device where I can redirect the audio output of my Android smarphone, and has a pair of analog outputs. Essentially a wifi host + DAC, that I set and forget. Bluetooth quality is not good enough, I don't need any signal processing.

Hi Gents,
Nob on this stuff, looking for the above with good sound for son budget around $600-800 fo a set.
Would appreciate your kind advice

Thanks

Hi, I have sticky faders on a Tapco 4400. Is it "safe" to use silicone based lubricants? What should I look out for? Should they be specific for electronics I think?

Hi,

I lost the lithium charger for a cordless screw driver. The charger cost as much as the screw driver to replace. The charge specs shows 9V 100mA.

When I connect the screwdriver to a power supply and limit current to 100mA at 9V. The power supply shows it is only drawing 1 micro amp.

Any ideas? I should see some current under 100mA if it working?

Any reason why it would not work this way?

Dear community,
I am in a process of repairing my Sony TA-N9000ES amplifier. I am familiar with electronic, but my skills and experience with power amplifiers are very limited. I hope to receive some advices. A few words on how it failed.
It was a daily use amplifier. Just mid range volume, 8 ohms speakers. I noticed no sound coming out. Checked the amp, it is in protection mode, blinking LED. Turned it off with a power button, after a 20-30 seconds turned it back on and... enjoyed a fireworks with lots of smoke.
After opening it up and brief testing found positive voltage on center channel output. Static component testing showed that most of the components in this channel failed or evaporated, taking out some of the board traces. Did lots of cleaning.... ! First picture shows schematic with failed components in red circles. Second picture shows the worst burned area, in addition to a few more traces just disappeared.

I think that the filament temperature of a valve is strongly dependent on the anode dissipation.
Does anybody know something about this ?
It is possible to determine the filament temperature by measurement of filament voltage and current.
Resistivity of tungsten: 300K 5.65, 1200K 30.98 1300K 34.08 1400K 37.19 1500K 40.36
Can anyone tell me the filament temperature for an 6DJ8, 12AU7, 6V6, EL84, EL 34, 300B and KT88 tube at zero anode dissipation and at maximum anode dissipation.
I think that tube lifetime and SPICE models are strongly dependent of filament temperature.

The 'Home' tag in the breadcrumbs in my theme now goes to where I already am, a fairly pointless non-trip.

I would expect a high-level "home", and I think it did that until recently?

Smells like an oversight/typo in the navigation. In fact it seems to do what the now-blank thread-title crumb 'should' do?

Hello, I have inherited a Grundig NF 1 that was still functional a few years ago, and I'd like to make some renovation on it. There are has two major issues (beside the usual replacement of caps and resistors) :

1 - the power transformer is made for 220 V main, and my main is rather 240 V.
I have seen in that post https://www.diyaudio.com/community/threads/photo-gallery.71300/post-6843380 the work that Pamook has made on the same amplifier. To lower the voltage from 230 V to 220 V he put a 12 V transformer in series with the main transformer. Can someone explains me the process and what kind of transformer I should use to get from 240 V to 220 V ?

2 - I know that it is recommended to replace the selenium rectifier with a silicium bridge, but some resistors have to be added as the voltage out of the silicium will be higher than the one from the selenium, if I'm not wrong. How may I calculate the needed resistors ?

Thanks a lot in advance.

Hi All,
I am looking at the possibility for using Beyma 15P80Fe/N as Subwoofer for Home theater. The idea is to build 2 diy enclosures using this driver.
When I simulated in Winisd, I get the below responses. With the Fs of 32hz, I am simulating a box tuned to 25hz with 400 watts signal (7 cubic feet enclosure)
Please suggest if it is worth building for subwoofer used for movies or should I wait for any better drivers as this is the only model dealer in India has availability.
Is there a better model to get most of it from this subwoofer (like horn loading)?
My original preference was for 18 inch but it is currently not available at the moment.

SPL




Transfer Fuunction Magnitude


Thanks

Hi, I ordered the board (from Peter Millet), the components for the board and Edcors PM-102.
Managed to build a quick set up to see what I bought and hear what I built... 🙂
I have alot of hum in da speakers...
When I power up it is there and a lower hum mixes in 3 seconds later...
Where should I start to eliminate da hum?

Tivoli Solid State Radio "Model ONE" vs. KLH Model 21 "TWENTY ONE"

Tivoli Model ONE vs. KLH Model TWENTY ONE
I need the schematic of Tivoli Model ONE. Who can help?

Here some URLs and attached pics - the KLH model 21 looks in much higher quality standart than Tivoli Model ONE - at least in the aera of the RF-IF unit (variable capacitor e. g.)

URLs to Tivoli Model ONE
http://www.diyaudio.com/forums/full-range/76959-tivoli-speaker.html
http://www.diyaudio.com/forums/parts/97391-tivoli-model-1-fm-aerial-connector-replacement.html
http://www.diyaudio.com/forums/parts/57858-tivoli-model-one-aux-input-modification.html
photos for albums/Audio/Tivoli Model 2
http://www.datasheetcatalog.org/datasheet/philips/TEA5710.pdf

URLs to KLH Model TWENTY ONE
klh model 21 with problems... - The Classic Speaker Pages Discussion Forums
The KLH Model 21 re-invented - Tivoli System Henry Kloss Model One AM/FM Radio ( Walnut) - Epinions.com
KLH Model 20 Plus - The Classic Speaker Pages Discussion Forums
Vintage KLH Model 21 AM/FM radio circa 1970's - eBay (item 260720654378 end time Jan-18-11 18:14:03 PST)

I found this very informative article on the Quad ESL impedance:

http://www.audiomisc.co.uk/57and303/interact.html

I decided to verify the impedance plot on my speaker, so I used an audio signal generator, a series resistance and an audio voltmeter. I set up the level so that 40mV on the voltmeter corresponded to 10 ohms. Then I entered the measured values in an Excel table and I got this impedance diagram:



I wondered how accurate is the electrical model against the measured values, so I created an LTSpice model. See .asc file attached. I had to modify the electrical circuit by adding a 1.5R resistor series to the 2uF capacitor representing the treble section, so the impedance is about 2R at the treble dip.



This is the AC analysis plot:



I did not measure the phase. From the analysis it seems mostly inductive below 100Hz, then capacitive up to 20 kHz or so.

Due credits to Sheldon (quadesl.org) for the reference to the ESL Dummy Load originating from Christian Steingruber:

https://www.quadesl.com/origRefs/ampload.jpg

And thanks to Jim Lesurf for the original model that I modified a little and used as the basis of the LTSpice model.

Hi all

My lil girl needs a decent bass. The kids bass at the music shop feels like a toy and sounds uninspiring to her and she is also struggling with fret buzz. So I thot to eliminate the potential for that and sort something out where she can go ahead and learn all the stuff at school without being burdened by also cleaning up the playing at the same time. The problem is that she is struggling to depress the strings with her tiny fingers

Time for a new project. The perfect kids bass

Materials, a fender style guitar neck and a mini guitar neck. Prepared for filling back the holes and drilling 4 four bass tuners. This project is an experiment building on the time and energies spent developing the TAXI Bass

Necks prepared for filling
Red oak round panel and some leftover birch planks for bodies

The search function is not working so I could not check if this has been posted in the past.
But when it comes to playing audio from a PC I have found nothing can beat this plus its free.

If you know of any GQ which is better than this please share. Also chk out the other audio s/w. They have.
https://sourceforge.net/projects/peace-equalizer-apo-extension/

Just finished fixing my akai amp and a bit disappointed with its output.
So I have these bose car amps lying arround. Which i want to use in my workshop.
My question pertains to the pin out.
And if the input to these is from line out of the car deck or the speaker out of the deck. Also if the input to these are difrential or not .
I hooked it up to a kenwood deck line out but got very faint audio.
I have joined both the vcc and ground pins. And powering off a car bat.

Came across this site whilst looking for information on how I might go about building a DIY Line-Array speaker system. We host yearly parties on our property, and our friends are all into Bass EDM music. So a couple times a year we have DJs out and throw a big party. The speakers that I have now work very well, and fill our space very well with sound, but I'm not super happy about the quality of the mids and highs. I'm into woodworking, software development, electronics, music! So, outside of the math and physics involved with speaker design, I can do most of the other stuff.

My current setup is:
(2) Rockville PBG18 Subwoofers each with QSC PLX3002 Amp
(2) Rockville 12.4 12" 3-way speakers each with QSC PXL1602 Amp.

The PBG18's work quite well for the low end, but the 12.4's leave a bit to be desired. They sound a little tinny and not very full.

I was looking to build (2) to start, and add more later, some line array style speakers that I could hang from my patio roof and aim down towards the audience (budget of about $3000 for a pair). Just from my initial browsing (I fully admit I don't know much about matching speakers (*yet)), I put this together for each speaker:
(2) Faital 10FH500 in parallel
(2) Faital 6PR110 in parallel
(2) Faital HF107 in parallel

Looking for any and all input regarding types of speakers, cabinet design, tuning ports, crossovers, etc.

Thanks!

Hello All,



Back in the mid ‘90’s I had the opportunity to acquire, at a very modest cost, a few Apex PA05 power operational amplifiers, along with their evaluation kits. The amplifiers are rated for an internal dissipation of 250 watts, and a maximum supply of +/-100V. The evaluation kit contained a very nice heat sink with a thermal resistance of 0.68ºC/W, and a large PCB. I experimented with them as audio amplifiers (see attached pictures and schematics). I had no intention of pushing the power envelope, I was happy with 20-30 watts into 8 ohms, so I used +/-28V regulated power supplies. I used the amplifier for a couple of years as an office system listening mostly to FM. It sounded okay with speakers, but when I tried to use it as a headphone amplifier, the background hiss level was so bad I gave up and put the amp in the cupboard. At the time the only measurement equipment I had was an analog multimeter and an analog oscilloscope.

Recently I had the occasion to put the amp back in service for a few weeks while I worked on my current office system. While I had it out, I thought I would look at the distortion spectrum with the QA401 (see attachment), which looks pretty ugly to me. The data sheet specs the THD at 0.01% at 1KHz at 1W. Anyone care to offer suggestions on how to go about cleaning up all that distortion and noise? By the way, I am aware that the safety ground is incorrectly implemented, and if I can solve the distortion problem and put the device back into service, I will correct this error.

Cheers,
ceulrich

What is the best way to replace the bulb with led in this circuit?

I am wanting to order two output transformers from electraprint. But not sure if I am giving them the correct data. Running el34 push pull ul, fixed bias at 40mA, B+ 450v

For electraprint
105w
4.6k plate to plate
100mA/100mA
50%ul taps
Load impedance 8 ohm

Would this be accurate?

This is my current office design:




Obviously, that corner bit is 'awkward' - perhaps a few cupboards that are hard-ish to reach.. or.....

A subwoofer for the cinema in the next room?


Questions:

1/ Would this be a good idea? Since I'm building this house from scratch I have a lot of freedom when it comes to e.g. the wall thickness, type, bass port etc etc. With the current sketch it'd be about 30 cu feet, padded with felt I guess?
2/ What's a reasonable wall width and material? 1 inch as I indicated here is probably a bit flimsy? Concrete? (no idea how to even create a wall like that.. a mould perhaps?) How about 100mm brick?
3/ What actual driver(s) should I get? What configuration? Depends a lot on how loud I need to go but as an indication the exit port is about 5m from listening and hitting 115dB (thx) at listening for say 10Hz would be ideal?
4/ Any suggestions around the exit port that has to tunnel through the wall? Does it have to be the size of the driver(s) or can I make something more reasonable like 5x5inch or so?
4/

OK, count me as one of the many that just love - love these speakers! I have the Quad ESL-63 and the ESL-988...and are my favorites!

And I trust what I am about to say is not to be taken as Quad Blasphemy!

Yeah, all those that say the removal of the dustcover does not change its sound at all.... and I agree. And understand I am not advocating the removal of the Dustcover as it will not improve the SQ....

But, that only can mean one thing - ready?

That because what you are really hearing is the DUSTCOVER, not the actual panels thru the Dustcover. The sound cannot pass thru the mylar Dustcover. The Dustcover is a measly 3um for this reason. Its Supersensitive Acoustic Coupling, not unlike a passive radiator in a box speaker.

So, if some agree that we are hearing the Dustcover only, the delay rings on the panel - how the sound propagation of these delay rings can somehow superimpose onto their exact locations on the Dustcover to do as they are designed to do... huh?

I have always wanted to build an infinite baffle type speaker (w/ tweeter, bass drivers, etc), and put a "box" around the baffle edge to be able to pull a 3um mylar on both sides to see if this speakers separate (front / back) airtight "Dustcovers" Acoustically couples all the low, mid, and high frequencies and and allows all the frequencies to emanate off one (well, two) common surface, just like the Quad or any other Electrostatic speaker...all with basic "box" drivers...

Go ahead, call me crazy.

Hi there,
I picked up a nice looking pair of RAM Electronics 100 Monitors the other day for £30 (£15 after refund). I soon discovered that one of the bass units (Dalesford D50/200)was dead. No sign of damage and the cone moved smoothly and quietly. Not sure what its fate was.
Anyway, I need a repalcement and my initial thoughts were to get Kef B200 units. I initially thought SP1014's which are quite easy to get. Then I found a link on Falcon Acoustics who have an interest in that company. The chap there suggested I should be getting the large magnet variety SP1039 or SP1054. Pricier and harder to find it seems. No mention made of the SP1022.
I wouldn't say that the D50/200 is a large magnet type, but the design is clearly B200 related but with inverted rubber diaphram. It weighs 1.67kg. The large magnet Kef's are about 2.7 to 3kg. The regular ones around 1.47kg.
I then wondered if I am better just going for a pair of new Monacor SPM-205/8 units?
Any advice. I want to keep any work low cost or else I will just sell for parts.
I think the one remaining D50/200 may help fund the unit purchase a little as they are quite uncommon.
Cheers

Two Lundahl LL1681; one is okay (on a Vero-Board with screw terminals).
The other one is defective: one of the secondary coils is not making contact with the connection pin.
I tried to open it once, but then gave it to it.
The single one can maybe be used for mono pickups?
70€ + shipping

Having just designed a DAC with a single-ended classA output stage which drives high impedance headphones well, I wanted to explore options for expanding downwards the range of HP impedances that could be driven. SE classA has a brickwall limitation on output current and goes into aysmmetrical hard clip at the point where the output current equals the bias current. As a result, it needs to be designed with a specific load impedance in mind so that current clipping isn't the primary constraint - the DAC is optimized for 300ohm (Drop HD6XX). Having played in the past with transformers for HP drive I figured it was worth revisiting this area but this time around going the autoformer (rather than transformer) route.

The disadvantage of an autoformer (aka 'tapped inductor') is that there's no isolation between primary and secondary but in this application that doesn't bother us at all. The upside is better utilization of copper resource, though the degree of this advantage depends on the target turns ratio. The greatest advantage comes in near-unity ratios. i'd like to explore whether a rudimentary volume function could also be included alongside the impedance transformation.

Since I have a box full of PQ3230 core sets I figured I'd make a start with that size. A couple of months back I built a 1dB step AF (autoformer) attenuator to sit between DAC and amp using PQ3230s so it was a matter of seeing how to adapt that for HP use. Adaptation of something already extant being much easier than design from scratch. There are two main concerns when the intent is driving HPs rather than the light load of an amp's input stage. The first is - 'what are the losses in the copper?' and the second is 'what's the bandwidth?'. These two concerns are inter-related as the more turns an AF has the greater its losses and the lower its bandwidth. So one aim is to minimize the number of turns. Pushing up against that though is a third concern - 'what's the shunt inductance?' - the core material being ferrite without a sky-high mu (as permalloy for example has) this does factor. So we don't want to go too low in turns or the trafo will 'steal' too much of the output current for its own energization.

The question of the bandwidth of the AF is something that cannot easily be predicted in advance, it has to be explored empirically. In order to make a first stab at it, I loaded my 1dB step AF with a 30ohm resistor and took a look at the HF roll-off. It showed a -3dB around 5kHz, definitely not sufficient for audio. The low-pass response is a function of the AF's leakage inductance - to get a wider bandwidth we need to get that leakage L down by at the very least a factor of 4 (which would give -3dB @ 20kHz, in the ballpark but not really ideal). Rather than build an AF with half the number of turns (to get a quarter the inductance, and hence leakage inductance which is a fairly stable ratio of that) I decided to run a sim. The sim showed I can tweak the HF roll-off upwards by introducing a cap across the 30ohm, thereby gaining a dB or so in extra HF flatness. So it looks as though I just need to build an AF with half the number of turns of my 1dB step attenuator. Since that was designed to handle about 9VRMS, the HP AF will have 4.5VRMS input voltage handling which is more than enough given the DAC only outputs 2VRMS. I will go for a 4VRMS handling to have a little more bandwidth in reserve as sims don't always closely match reality in trafos.

The PQ3230 core has a cross-sectional area (Amin) of 142mm^2 which gives 161turns/volt at 20Hz. So to handle 5.6V peak at the worst-case frequency I'll need 5.6*161 = 901.6 turns. Let's go for 900. To get the required wire gauge we divide the available winding window (101mm^2) by 900 and take the square root. 0.335mm external diameter wire. Wire's sold by internal (copper) diameter so this says about 0.29mm to allow for insulation. If the wire's enamelled then allow a little more. Knowing the wire diameter needed we can estimate the total length and hence DCR and with the DCR we can check if the copper losses are going to be sensible into various HP impedances. The rule of thumb I've seen is that the driving impedance should be not greater than 1/8th of the HP impedance. So for the lowest impedance HPs this gives about 4ohm source impedance as a ceiling.

From my handy trafo design Excel crib sheet I see that PQ3230 bobbin has an average length of turn of 67mm so with 900T we'll have 60m of wire. 0.29mm wire clocks in at 0.27ohm/m so that's 16.3ohm total DCR end-to-end. Sanity check - the original 1dB step AF measured at 79ohm so we are in the region of 25% as predicted. To get the effective DCR 'seen' by the HPs we need to know the tap ratio - 300ohm down to 30ohm is sqrt(10) in voltage ratio. Whereas calculating effective impedance in transformers is easy, I'm not sure my mental heuristic works in the autoformer case so I'll run some sims as what Daniel Dennett calls 'intuition pumps' and then continue in another post.

Hello everyone
I have a polytone IV latest version.
the toroidal transformer make hum.
This happen without any cable connected .How can I solve this problem?

I have assembled the stereo version of the amplifier in the attachment. My problem is when I give power to the amp, after connecting the speaker, the series bulb is in "ON" state indicating DC voltage in output. If I give power first and then connect speaker there is no DC voltage at output and if I connect an audio input the output can be heard from amp without no audible distortion. Both channels have same problem. Please help me to correct the problem.

A japanese bok ISBN4-416-19209-6 (363 pages, printed 1992, Koichi Shishido) describes the following tube amps:

*DA30 8W single end, interstage transformer
*811A 8W single-end, interstage transformer
*801A 8W single end, interstage transformer
*826 8W single end, interstage transformer
*RCA-808 12W single end, interstage transformer
*RCA-800 10W single end, interstage transformer
*8012A single end, interstage transformer
*826 8W single end
*RCA800 28W PP, interstage transformer
*RCA830B 15W single end, interstage transformer
*UV-838 35W single end, interstage transformer
*805 50W single end
*6N7 7W PP
*6L6 PP
*4D32 20W single end
*preamp with 6DJ8

Hi.
Somebody know the curves for c3g c3m tube in triode mode?

in that little lenght does brass really degrade sound quality ?

When I land on the forum home page I see the header in the attachment below..

I am guessing that the text was meant to be...

Projects by fanatics, for fanatics. Get answers and advice. For everyone wanting to learn the art of audio.

Click to expand...

Would that be correct ?

In my Poppulse T180 amp one of the TA 2022 IC-s (one per channel, BTL mode) gave up the fight (no heat conducting paste between the the IC, and the heatsink ! ) , so I ordered one and replaced tha failed chip. The problem is, that now I have almost 1V DC on the speaker terminals, and the circuit uses two trimpots to adjust the 0V DC on the output. I have the data sheet of the IC, but it does not tell you how to adjust the DC offset in BTL mode. Any idea?

Hi all. I am searching for this mids from Scan-speak. I own one pair of CREMONA Sonus Faber and I have broken one.
Someone have one pair?
Best regards

Want to build an amp and feel satisfied with it.

Well, I was always wondering about this one since I heard it some 20 years ago.
Then last week by chance found a perfect condition specimen on the local flea market for peanuts, so I decided to give it a chance.
Doing the compulsory homework on a 30 years old amp -replaced all electrolytics in the power stage with Silmic II-s, and Kendeils in the power supply + ultrafast rectifiers- I was totally blown away from what came through on this old piece of hardware....
Having owned, built and listened around 100 different amps (some really good ones too) in the last 30 years, let me tell you, this is a very different animal as far as speed and transparency concerned.
Maybe I am just getting old and losing my marbles, but let me tell you, these guys at Kenwood knew something by then that very few manufacturers are able to repeat today.
The sheer clarity, transparence, and attack of this little amp is breathtaking.
I am hearing information in the upper octaves that sometimes just plain scare me, because they come through with such a realistic way, I often confuse them with environmental noises. Never experienced that with ANY other amp before.
On the attached pictures you can see, that they did their homework on output stage design.... Split feedback for the VAS and current amp stage, critically applied phase correction and speed-up components at all place.
Even that old Darlington power pack does its job in an excellent way, this thing reproduces 40 kHz square waves perfectly, without overshot and ringing.
After all, I am curious about some expert opinions from you, any comments advices, criticism concerning the design?

Hi all.
I build jlh 2005 using Paulb circuit and pcb. Now i face issue sound is too low. Use +-30v supply range. And use 2sc5200 for power output. 2 pcs 2sc5200 already died cause over bias(sad)
I double check hfe value for bc560, bd139 and bd 140 all in good range.

I don't have oscilloscopes and signal generator to measure input output gain.

I spent a weekend writing a small and simple software program that performs most of the DSP features in the RME ADI-2 DAC/Pro, mainly for using it personally on a laptop when travelling without the device.

The program applies DSP system wide based on CamillaDSP, and has identical output compared to the RME ADI-2 DAC/Pro, with various features including volume adjustments, software muting, RMS and PEAK volume calculations before and after DSP, Width, M/S Proc, Phase calculation, 5 levels of crossfeed, EQ for headphones or room corrections, Loudness, De- or Pre-Emphasis, and DC Protection. It also has Digicheck's 30 bands spectral analyzer for left and right channels, and can give identical results as the ADI-2 does.

The implementation follows ADI-2's pipeline as much as possible, sometimes exceeding the hardware limitation of the original device. For instance, user can have as many EQ bands as possible. On the other hand, it has longer latency and higher CPU usage, as the processing is not done in hardware.

I believe the software program could be useful for many people so I decide to make it open source.

Here's the github link: https://github.com/Wang-Yue/CamillaDSP-Monitor

Please play around with these features, discover the usefulness, and have fun!

Bear in mind this is alpha quality software. It works well in my setup, but whether or not it will burn down your house is unknown, and I hold no responsibility for that. With that said, all the bugs or glitches are due to my sloppiness, not CamillaDSP or RME.

Any interest in a pair of consecutive serial #LE15A 8Ohm in need of repair. Parts only.
Located in Utah. Please Make offer

Any information on this?

I'm just experimenting with a bass module with 4 identical woofers in a vertical OB array. Specs show impedance is 7.04 ohms. Would like to keep it close to that and easy to drive. Could someone direct me to a wiring diagram that will accommodate that. Thanks.

I'm from Brazil, and here we have several styles of boxing in different states of the country. And in the Northeast region of the country, the 15-inch inverted speaker horn box is widely used, in various types of systems or channels, with a 60cm box; 50cm; 1m (23.622 inches; 19.685; 39.3701) of horn, and 32 liter liter housing, varies from project to project and housing developer.

!I wanted to know what program I can design them!

There is a box that has the DUCT, right triangle with rectangle. (here in Brazil we call the air passage a duct) And I managed to make the square area of it, but I don't know if it's right!
The math I did was this: I multiplied the sides of the right triangle and divided by 2, and the sides of the square multiplied. Example: 12cm X 12cm= 144 ÷ 2 = 72cm².

Square: 42cm (width) X 7cm (height) = 294cm².

Once you have these 2 results, add the 2 = 366 to the area of the 2 together. I don't know if that's how I calculate. I used centimeters, but you can convert the measurements you use and test.

Hi all
The above mentioned amp is coming on but there is no output. Anybody has any schematics for this or any idea where to start with.

Someone reached out to me from NJ wanting to send me a kicker kx600.1 and a kx350.4 for repair. Wanted to see if there were anyone in his area who would be willing to repair his amps before I have him send them to me?