Anyone have the proper idle current/bias settings for this amplifier?

Running about 8mv drop across the 0.1ohm resistor at idle with an 8ohm load connected. Seems kinda hot.

Hello all!

Just getting bit by the tube bug, and trying to figure out the best way to spend other people’s money on some Christmas present suggestions this year. Have no experience with Hifi let alone tubes, but want to put together a cool, interesting-to-me hifi setup for a small room.

I see highly respected designs all over the place (Tubelab’s SPP for example), but they do not feel modular/cheap enough for a beginner to open one box and start soldering with the intent to discover if they even like tube amps in the first place!

Does anyone have experience with these Douk/Nobsound kits? I recognize these may be sacrilege, etc. but I am tempted by the low price/high modularity while still getting to build it with my own hands.

For the same-ish money, the Tube Cube | 7 offers me a highly-reviewed and low risk opportunity to listen to a good quality tube amp but without the satisfaction of DIY.

Suggestions welcome!

Hi - really need some help to try to trouble shoot this.

Loud constant thumping noise when I mute the radio or turn the volume down to 0.....sounds like the speakers could blow if left on too long. This happens when I turn on to FM and Bluetooth connection. Also the speakers are making static/hissing noise. Also, makes a popping noise when switching from FM to Bluetooth, USB.....

I have a Camper and the radio is a Jensen JWM22 RV radio that only puts out 6w X 4 ch ..... 2 speakers inside the camper and 2 speakers out side. I’ve connected a small Pioneer GM-D1004 amplifier class D 4 channel RMS of 45w X 4 using high inputs (only option I have). I only connected the 2 outside speakers…..only using 2 of the 4 channels. The other 2 channels are not being used at this time. The 2 speakers I’m using are DS18 ZXI-454 (4x6) with RMS 60w per speaker. The amplifier already has a ground and power wire connected to the wire harness 14 gauge.

I connected a car amplifier to the stereo and it makes static noise that is very noticeable, even when playing music. Without the amplifier it makes very little noise …barely noticeable when the volume is muted. I’ve unconnected and reconnected everything and it still makes the noise. Also, when I turn down the volume to zero or mute the volume it makes a very loud continuous popping and other loud noises until I turn the volume back on. I’ve connected power and ground to the battery and I also tried using a different battery. Also tried connecting the ground to the frame.

Any suggestions on what I could do to fix this?

I would like to add a subwoofer one day for tailgating …my main concern is getting the above fix

Boxsim seems to be a full featured system simulator:
http://www.visaton.de/en/literature/software/downloads/index.html

Up to 8 loudspeaker drivers and up to 6 amplifier outputs with separate filters
Takes account of diffraction at the baffle
Frequency response along the axis and in over 20 other directions
Phase response is calculated separately for each driver
Separate impedance response for each amplifier output
Beaming effect and energy frequency response
Crossover editor with freely configurable component positioning and automatic crossover optimiser
Cabinet variants: enclosed, bass reflex, bandpass, biventilated bandpass
Import of frequency and impedance response from many standard measuring programs (e.g. ATB, Arta, JustOct)

I gave this program a quick try and here are some of my impressions:
- The schematic editor is clumsy being a grid where you choose what component to place - it works.
- The simulator is a bit slow to compute taking about 3 sec after a single schematic value
change to show with a 2 GHz Core2 processor - I should move to my i7 I guess.
Xsim responds instantly with the 2G Core2.
- The polar plots, actual circular ones have such large steps in angle, every 30 deg from
what I see that lobing is most often missed. Is there a place to change the step size?
- Off axis response shown as a family of curves also steps in 30 deg increments which is
also too large.
- Program loads with all Visaton drivers available have not figured out how to add a new
driver with FRD, and ZMA files.
- Predicted phase response looks odd, but probably have to correct for time delay in
measurement files.

Has a lot to offer but all in all Xsim has a better feel to use but lacks many of the features here.

God bless my soul, how I love my local charity shop and the random speaker bargains they serve up. 🙂

They had a flippin' random 1980's bargain that even I would take on for £30 this week. For those of you who don't know, Wharfedale had a superb cabinet building shop up in Idle, Yorkshire. Even if the speakers are broke, they are sufficiently solid to be used as stools to sit on round your home. 😀

Enter the Wharfedale Shelton XP2. I had a vague idea that this was a 20L closed box 8" bass plus 3/4" mylar tweeter design. A design about the size of a very big box of Kellogg's Corn Flakes. Which probably meets the WAF criterion.

TBH, they aren't bad for £30. It all works. Good bass response. The expected lively mylar tweeter response in the KEF T27 mold. I am very pleased with them. I was expecting a big roll of stuffing inside the closed box. And it turned up. The crossover completely surprised me. 8 elements!

So far I have counted 2x 1mH coils, two 16uF Elcap NPE caps, and a smaller tweeter coil around 0.3mH and perhaps about 3uF cap. Big surprise is a couple of tiny elements around 33R resistance and 0.47uH. I think this must be a BW3 design with some consideration to RF impedance. Ah well, we shall investigate further this Golden Age of British speaker design.

It sounds excellent for sure. Diana Krall, Kate Bush and Chris Rea all sounding better than on most Android tablets. 😎

Got my shelf a rare find
One pair of LE10H and one pair of 2405 tweeters Both of them are inbox brand new and in perfext shape ....Foams are like new
they have been stocked inbox in a shop never opened
It appears that the conditions there where perfect so foams have absolytely no probs

Intention is to make something like a studio monitor
is this possible ? will these two work nice together ?
Can any one suggest an enclosure design that will be raltively small in size and work well with these units ?
good eficiency is a target rather than a lot of power

Hey folks,
My group and I are working on building a musical instrument using mostly analog circuits and are running into trouble with beat frequencies and sound quality. We're getting some pretty strong beat frequencies and would love some advice from an audio engineer on how we can combat the ****** sound we're getting. Here's some more about our system:
12 555timers in parallel for each frequency -> LM 386 op amp as a signal combiner -> bandpass filter -> (amplifier/filter (https://www.amazon.com/5V-12V-Ampli...words=arduino+amplifier&qid=1700168828&sr=8-3) chip -> 5W speaker. Currently, individual notes are working well but combining 2+ frequencies results in a large degradation in sound quality.

What could be the source of our terrible sound quality when playing multiple notes? I understand that we're amplifying twice, we also attempted to mix the individual signals together by wiring them together directly through 120k ohm resistors. Any thoughts?

Thanks in advance

YuanJing's website list this DAC but its out of production now.​

If anyone wants to part with his unused ones let me know. I am looking for up to 3 boards. Used or new.

Here is a image from the board:

24Bit / 192KHz USB DAC Decoder Board AD1955 + WM8805 + PCM2706 Optical, Coaxial [Upgraded Version]​

If offer these kits with the passive components on the hood.de market place :​

https://www.hood.de/i/komponenten-k...erstaerker-lm3886-lm2876-lm3876-113751030.htm

You can build the kits with the LM 3886, or a lower power LM 2876. The latter seems to be more available and is on the TI website too.


E.U. buyers please use this portal. But I can send these to other destinations on request.

Hi,

I have a stereo amp. Here is how the back looks :






I want to connect an active subwoofer to it. Can i use the Rec/line out to conenct my sub amp and drive my subwoofer. If not then can i use a resistor based attenuator at the speaker out and convert the speaker out to line level and feed that to my sub amp.

Thanks

I bought a pair of Aiwa speaker but unable to find specs of it can somone help me finding the specs

I have attached some pics of speaker

I have for sale some IC components
The goods will be shipped in a cardboard box , transistors will be packed in antistatic bags. Ship from Poland.

Payment: PAY PAL

I don't send to RUSSIA , IRAN , SYRIA , IRAQ , LIBIA , VENEZUELA , NORTH KOREA

Shipping : to EUROPE ( including ISRAEL & CYPRUS ) - registered priority mail - 5 EURO

NORTH AMERICA (registered priority mail ) 6,5 USD

Rest of the WORLD ( registered priority mail ) 10 USD

Below original photos.

If you buy for 65 euro ( 70 USD ) or more shipping is free.

MINIMAL ORDER QUANTITY = 1 pc

Prices for 1pc. EURO / USD

1) IRS2092S SOIC16N INFINEON STOCK: 15pcs. 2,15 euro / 2,31 USD
2) TDA7294V MULTIWATT15V ST SOLD
3 ) LT1166CN8 DIP8 LINEAR TECHNOLOGY STOCK: 2 pcs 6,80 euro / 7,10 USD
4) SSM2019BNZ DIP8 ANALOG D. STOCK: 2 pcs. 6,23 euro / 6,68 USD
5) J113 TO-93 ONSEMI STOCK: 100 pcs. 0,193 euro / 0,207 USD
6) IRF540N TO-220 INFINEON STOCK: 50 pcs. 0,79 euro / 0,85 USD
7) IRF9540N TO-220 INFINEON STOCK: 25 pcs. 0,86 euro / 0,926 USD
8) MJE15034G TO-220 ONSEMI STOCK: 50 pcs. 0,79 euro / 0,85 USD
9) IRFP9240PBF TO247 VISHAY STOCK: 25 pcs. 1,56 euro / 1,68 USD
10) STTH802 ULTRAFAST ( max. 20ns ) single diode 200V 8A TO220 Mfg. ST STOCK: 15pcs. 0,57 euro / 0,61 USD
11) KSC1845-F TO-92 ONSEMI STOCK: 500 pcs. 0,09 euro / 0,0927 USD
12) KSA992-F TO-92 ONSEMI STOCK: 200 pcs. 0,09 euro / 0,0927 USD
13) LD1117-3.3V TO-220 SINGLE GAUGE ST STOCK: 10 pcs. 0,375 euro / 0,41 USD
14 LM337SP TO-220 ST STOCK: 10 pcs. 0,636 euro / 0,68 USD
15) MKS2 47nF/100V 10% pcm = 5mm WIMA STOCK: 200 pcs. 0,159 euro / 0,17 USD
16) MKS2 1uF/63V 10% pcm = 5mm WIMA STOCK: 100 pcs. 0,375 euro / 0,41 USD /
17) MKS2 2.2uF/50V 10% dimensions: 5 x 7.2 high.10mm pcm = 5mm WIMA STOCK: 200 pcs. 0,68 euro / 0,73 USD
18) Male socket for panel with fuse holder ; rating voltage 10A / 250VAC - Mfg. LANZ STOCK: 20 pcs. 0,59 euro / 0,61 USD
19) UC2-5NU ultra miniature relay 5VDC ; 2 FORM C , 10,6 x 6,5mm ,High 5.3mm - Mfg. NEC-NEXEM STOCK: 8 pcs. 1,34 euro / 1,44 USD
20) IR2110 PBF DIP14 INFINEON STOCK: 10pcs. 2,13 euro / 2,29 USD

Regards
Robert

1 new assembled lighter note volume control designed by Uriah Dailey.
It's new pulled out from this chassis, customer could not pay , so that's that.
60 euro
Ps. It's the red boards

Hello.
I have 24 pieces of Fischer sk 96 150 sa.
All new, took one out for photo.
Dimensions are on photo length is 150mm.
Take all for 70 euro.

HI, Im parting out with one of my XTZ Edge A2-300 amps. Utilizing the Icepower A300 modules XTZ did a great job with this. it is a spectacular amp and certainly best Icepower Ive heard;. Original box Manual available

specs per website 300 watts into 4ohm cont, she packs a punch


400 net to me paypal SHIPPED USA ONLY

I have a rigol ds2072a for sale, it is fully unlocked and is in essence a ds2302a, only difference in this ds2000 series is software related.
The original fan is replaced by a noctua fan with similar specs, but noise is much less, it was really annoying.
I think it's been used less than 100 hours.
No scratches, bumps or anything, like new
300 MHz analog bandwidth

Wider vertical range(500uV/div ~ 10V/div), lower noise floor, Better for small signal capturing

Max. sample rate 2G Sa/s

15Mpts standard memory depth or 56Mpts with option

Innovative "UltraVision" technology

Waveform capture rate up to 50,000 wfs/s

Up to 256 Levels intensity grading waveform display

Up to 65,000 frames Hardware based Real Time waveform, Record, Replay & Analysis functions (Std.)

Complete connectivities: USB Host& Device, LAN(LXI), Aux.
Asking for 470 euros.
EU only

Selling my XTZ Edge A2-300 is near mint condition. Any questions please ask. Paypal payment. Shipping free USA Cross posted its on ebay and Audio mart. Cheapest price is here for members. 420 Shipped USA

I accidently fried my lcr meter while reconditioning large capacitors, I want something like the der-de5000 I'm interested in a swap, I do have some stuff here for sale.

https://www.diyaudio.com/community/threads/nelson-pass-hpa-1-clone-pcb-only.400969/#post-7406245


Back in July I bought a pcb from member HRDSTL, but having now bought his working populated board I have no need for the bare pcb so offer it for sale.
Offering it for the same as I paid - 15€ or £13 plus shipping.
Beware that due to the catastrophe known as Brexit, buyers in the EU may have to pay tax on receipt.

See link above for picture of board for sale.

I'm in Shrewsbury UK despite the EU flag.

I have received an order of Jeff Young's HPA1 clone boards from JLCPCB but do not need 5 of them. They are 2 oz copper with ENIG. $30 each plus shipping and any PayPal fee. These are sold at what they cost me. Please pm if interested.

Did you order from Newark before? Did all transactions go smoothly etc?

I never heard of them or of the somewhat obscure op amp gain control booster.

Id like to try a line level preamp booster # 50-14820 if its quiet and quality stands up I'd even continue to use it.

Anyone have a good idea why On Semi lists the fast but no current gain or voltage handling KSP10 as an audio transistor that nobody uses? And, why all the good audio signal transistors that they still make aren't listed with their power transistors under the audio classification? No big deal but it kinda fries my gourd.

Hey there. I recently received a set of Burson V6 "vivid" dual opamps for testing out from SSaudio, and am writing up my experience with them. Most of you might find it a bit strange seeing me outside of the Tubes/Valves forum 🙂

This is the first post of several (an introduction, really) so that I can get the ball rolling on getting the review up.



First off, let me state that I was offered these samples for testing without charge, and that I am not being offered any compensation for my review, I simply agreed to post up my experience with them in return for being sent samples. I do not sell them, and am not profiting off of this review in any way.

Second, let me say that those of you who have seen my posts may know I do not mince words. If I think something is poor quality, poorly engineered, or downright stupid, I will state so, usually pretty clearly 🙂 I wont be giving any headstart to these simply because they were free, or based on reputation or "perceived" quality. I will be as honest as possible.

So, here we go...

I do not own very much solid state gear, and don't buy much pre-made gear. My intention in trying these out was to see how they perform in DIY projects specifically, as that's my focus in audio overall. I do not currently have any test equipment other than a DMM and my ears. I'm very much an "average" guy so far as this is concerned, and on a budget too. If anybody else wants to try these out and run some real tests on them, drop me a line- I'll gladly lend them out so that you can run THD+N measurements.

My first setup- as pedestrian as it sounds, is a Basic CMoy circuit used as a general purpose preamp. The only modification is the use of a TLE2426 rail splitter reference to an OPA134 active ground scheme. I usually run my favorite opamp here- the OPA2132P. It's quiet, clean, and sounds good, with a characteristic dark/mellow Burr-Brown "signature" that I happen to think sounds flatter than some more expensive opamps. I also have a pair of OPA627 on a browndog adapter I run on occasion, although it's a trivially simple circuit for such a fancy chip. It performs excellent in this preamp, but it doesn't really shine too much better than the OPA2132 in this application- maybe for use with very clean reference monitors, or very nice headphones. I also have a selection of other opamps on hand I will call out on occasion for comparison.

Second setup- Full-range speakers with tube power amplifier. Speakers are dual Faital-Pro 3FE25-16 in a .53X scaled Karlsonator speaker constructed with foamcore, from the now legendary thread in the Full range forum. Power amplifier is a DIY 6N1P/6CW5 push-pull setup. Regulated screen voltage, concertina splitter, and solid state rectification with mosfet ripple filters. Very quiet and clean amplifier, capable of ~22 watts or so before soft clipping occurs. This combination is on 12+ hours daily as our main sound system, and is very "transparent" with any changes upstream being quite noticeable. It is usually used with a Samsung Galaxy Tab 4 tablet as a source, directly connected.

Third setup- PCM1794 dual-mono DAC, on a "HIFIDIY) PCB. The PCB utilises dual-opamp footprints for the I/V conversion with datasheet values for the resistors and capacitors associated with them. This is the primary reason I wanted to test these opamps, as I don't like traditional opamps for I/V conversion all that much. Here they use the NE5534 or dual NE5532 on adapters, although I have also used a few others here as well, and will call them out as needed for comparison. This gets it's signal via a CM6331A USB board.

I also have a few other projects I will try them in, and will update the posting as I go.

Next up- I'll post my initial review/impressions of the Bursons themselves, and we will go from there.

Selling for $70 + shipping cost and any fees.

Contact me through PM

I have some leftover CANARE 4S11 cable that I would like to use to create a short sub woofer cable for a REL T Zero.
I only need 3 of the 4 wires, so what should I do with the remaining 4th core?

Leave it and don't connect it to anything or join 2 together and use it for the minus/ground
Thanks!

Hi to all,
a friend of mine, has a couple of PM 845 Melody but the audio is very bad.
We think about Bias setting but I can't found the service manual to measure and setting the bias.. Someone can help me ??
Thank you in advance.

Hello there,

after reading for months i decided to make my self finally an account, because now its time and i need ur support.

i am 22 years old, computer science student from germany. Until now i have always build either kits or subwoofers calculated with winisd. i have a umik1 for measuring

I am planning to build a 3 way floorstanding/ big standmount 3-way.

target specification:
-fully active
-should work without subs until 90dB(one preset with and one without sub)


i already bought/have:

subs:
2x2 mivoc aw3000 in 40l cb impuls compensated with sure dsp, can produce 30-80Hz +-2dB at 100dB



new speaker:
2xhypex fa123
2xkef sp1753 with flare



I am Planning to crossover at 350-400Hz and 2600-2900Hz
Woofer deaprtment should be smaller then 70l
Id like to stay below 28cm width and 40cm depth



I have yet not decided on woofer configuration, budget should not exceed 500€ for both speakers,
i thought about using subwoofers because i plan to cross quite low but i have never used subwoofers above 120Hz before is this a good idea?

1.
my first thought was to use 4x sb17nrx2c35-4 for each speaker to build somethink like a kef r11 but closed
~430€

Vituixcad(qtc=0,707, closed):
40l fb 69,9Hz

+headroom for eq
+with subwoofer should be possible to produce 110db >80Hz
-i dont user their mids at all(kind of a waste 😀)



1.1 same drivers but woofers impuls compensated like blade but in a floorstanding speaker with big baffle roundover at the front

+really like this idea
-i dont know if this approach even works in my room/ in general
-how do i simulate this kind of approach?

2.
use 2x dayton rs225-8
~380€
Vituixcad(qtc=0,707, closed):
44,3l fb 53,5Hz

+seems like a great performer
+good price
-i dont know if id like to look of it


3.
use 1 sb satori wo24p-8
~370€
Vituixcad(qtc=0,707, closed):
34,2l fb 46,4Hz

+seems like a very good driver
-bigger then everything else
-low max spl
-expensive



4.
maybe 2x visaton gf200in cb....

tiw200 a bit big but should work in a smaller box with eq / linkwitz transform


as u can read there is way to much posibilitys in woofer department and i cant deciede what to do and i find more woofers every day like wavecore, seas....

Can u tell me if my idea/plan with closed woofer is a good idea and which one u would chose?


Kef looks quite nice in room nearfield measurment and vituixcad with basic crossover between ht and mt

I just received a pair of Hi-Fi rated 6.6k 20 VA P-P transformers from Musical Power Supplies. I plan to try them in a push-pull circuit using the 6LR8 vertical oscillator/amplifier tube, with a folded cascode differential front end and an active auto-bias circuit of my own devising. Ohter alternaives for output transformer include a pair of Hammond 1620s I have floating around and a couple of smallish P-P transformers I scavenged from a Wurlitzer organ amp chassis that used a pair of 7868s as outputs.

I'm opening the package to have a look at the transformers, and I can already smell the fresh varnish. - cute lil' buggers, they are.

Selling this gigantic silver mica, collectors item? Perfect for your new Jurassic park fence? Paper weight?
30 euro?

Hello,

Well, I’ve yet again pooped up with a cabinet, my ADHD gets the better of me and the thing changes direction with every new idea I see..!!! Currently I have a pair of cabinets with the intention to use alpair 10p’s I was following the Woden Simple Reflex ov9 but wasn’t too keen on the tall and skinny look..!! Sooooooooo I have made attempts to go a little shorter and longer. My internal measurements are
200mm wide / 335mm high / 300mm deep. I have 2 x 50mm x 120mm ports.
Without bracing it is 20.1L with bracing it’s approximately 17.9L

Driver (centre) position is proposed at 110mm from internal corner and I was planning to place the port in the rear approximately 60mm (centre) from bottom internal corner.

I’m also open to building larger bookshelf boxes, not sure if I’m looking in the right places but they all seem rather compact.

I would also like to try a compression driver and horn a top this beast if it ever gets past the…. If it ever gets built..😝😝 just copped a peek at the Sinjisu Audio super hiro, mind is drifting towards something like that..!!

Im very aware that I’m asking a lot for someone to do the calculations on this but please could someone that is a bucket load smarter than me, ideally does not have ADHD ( 2 ADHD’ers on a project is a race to the bottom), and is generous enough to help, please provide me with some sort of encouragement that this will work or is it firewood..??!!! Lol

Can’t tame the neurological diversity that is my brain..!!!

Cheers.

🔫

I am experimenting with Usb cables form different brands from cheap to very expessive ones. Because of the reults, I deceided to build own usb cable. Till now i used famous factory branded cable with 90ohms impedance. Before i start to make my new one with bare wire I started with impedance calculation. When i put "Factory" cable dimensions in calculator i don"t come close to 90 ohms. If I think correctly ... impedance between paralel D+and D- wire should be 90ohms and also impedance Between D+ and GND and D- and gnd should be 45-50ohm. So therefore should be drain wire on the picture connected to gnd pin not shelf? So when i made cable drain wire was connected to gnd together with gnd from power supply +5 and GND wire. Then was copper shield connected to metall shelfs on both sides with no conntact to one of 4 pins on connector. Any idea where my thinking was going wrong way. Factory was for sure knowing what they are doing...

In the last six weeks, I have been targeted by extremely rude and aggressive solar power salesmen. They really want to put solar panels on my house.

First was at Home Depot. I had hired a helper with a truck and we has a large order to put together. I was buying siding and supplies for my project (almost done). We were very busy and time was a factor. This guy really bugged me and wouldn't take no for answer. He didn't seem to care that he was interfering with my business. When I walked out of the store he was screaming at me.

My doorbell rang a couple weeks later. I couldn't see who was out there (I was alone) and I opened the door. The sales pitch started immediately. "I'm not here to try to sell you something" and thirty seconds later he's trying to sell me solar power. As soon as he said "solar" I slammed the door in his face (he did lie to me just 30 seconds earlier) and he screamed at me through the door for about 30 seconds.

What gives? Is this what they teach salesman now? Do people actually buckle and sign up because some young prick screamed at them? I'm missing something here.

I am looking to replace the four JJ 300Bs in my Kevin Kennedy-designed monoblocs. The last time I did this I bought from BTB in Germany, but that was pre-Brexit and I would rather avoid the pantomime of dealing with import duties from the EU.

I am looking for a matched quartet, and would prefer to stay with JJ. Can anyone recommend a good UK supplier who keeps a large enough stock to be able to guarantee four well-matched valves?

Alex

Hello,

I am looking to build a small amp with these tubes. Is there anything dramatically wrong with this simple circuit? Or would it be a decent starting point?

Thanks

Just done a service on one these old C Audio RA1001 amplifiers. UK made Mosfet outputs. Sounds very good! Plenty of potential to add more MOSFETS and filter caps. Needed the fan oiled, cleaned, a few dry joints, new caps and slight damage to a trace needed repair. Clearly this one has had been repaired in the past. New zobel resistors been installed (oscillation problem perhaps in his history)

It's a shame many of the PA amplifier manufacturers moved away from MOSFETS. HH Electronic, C Audio, BK Electronics, Citronic... All UK made.






Exicon and SML


Potential of a short on metal cable stay coming away from board.


Trace repair


LED very bad dry joint!

Hi

I am selling a pair of 8055z OCC copper.
Ratio is 1:10
Very good condition

250 eu. + p&p from Italy


https://www.sowter.co.uk/specs/8055.htm

Walter

Here in pictures if you ever wondered how to remove a dust cap without damaging a driver.

With this tweak I changed a "bass driver" to a fullrange driver. Got approximately +4 to 5 decibels above 1.5 kHz.

The aluminium voice coil emanates a lot of good high frequencies usually getting lost being buried by a dustcap.

I use further dsp correction together with a current drive amp to lower distortion and get linear response.

Usually I cover both sides of the diaphragm with aluminium foil to get a sandwich cone as DIY "for free"

HI, I purchased a used California cdplayer model Aria (with valves), I think it is the MK1 version.
I have some questions.
Inside there are two LEDs, one LED turns on after you hear a clickKK... I assume one or more relays switch , the other LED never turns on. It's normal?

Do you know where I can find documentation regarding this device? User manual, service manual....

Some other questions, of secondary importance:

What is the "CM" function button for? See image with yellow arrow.

What is the "FTS" function button for?...see image. When I push this button the relevant LED starts to flash. If I push the button again the LED goes back off.

I attach some images.

Thank you

I hava managed to find an adapter for the Eighteensound HF drivers https://en.toutlehautparleur.com/ad...4-inch-to-2-0-inch-for-nd1480-and-nd1460.html

They mention that it works together with ND1460 and ND1480.

I am planning to order a set of NSD1480N, and wonder, if it fits?

Sorry for the typo in the title - it sould be monopol / cardioid bass mode
Hi all,
i have read quite closely the ASR thread;
https://audiosciencereview.com/forum/index.php?threads/ggntkt-model-m1.12959/
and have tried to copy the idea and run a simulation with BoxSim ( i am used to it since a decade, i know that VituixCAD is better but i am no good with it)

I have attached the BPJ file zipped in an archive for those who want to play around with BoxSim, i use the V2.1 DE Version, the file should work also with the V2.0 EN Version
The monopole mode is a piece of cake to simulate, bur i was wondering what have to be done to get the cardioid mode to run that is much better when the speaker need to stand very close at the wall. I have taken the speaker chassis available for BoxSim from Visaton, in VituixCAD the simulation could be done much more closer to the original using the original SB Acoustics 6.5 inch woofer, but it will be difficult to have a decent simulation of the Celestion compression driver mounted in the proprietary 120 X 100 degree directivity pattern waveguide.
As soon as i have understood what have to be done to get the bass cardioid mode to run i would try something similar with some KEF coax chassis that i have - KEF SP1753 4.5 inch as mid high coax that would need three additional woofer or KEF SP1716 8 inch that would need only the rear woofers in addition.

Hope to find some fellows interested in this topic!

- Stefano

PA150 LM3886 pcb with all components to complete less the audio input capacitor "68€ more shipment"
IC's are new and are not applied on the pcb,like main capacitors,power connectors and SMD output resistors
the other components are already assembled, with genuine components,like on the second picture.
Machined Heatsink with the machined copper hardware and ceramic pads can be supplied the cost is 78€.
DRV134 and gold plated pcb can be supplied if requested cost is 16€
I have also power supply pcb's for who want one model the power supply can be used for powers up to 400watt
and the other for powers up to 800watt, power supply partial assembled as example.
Tracked shipment, shipment to US on request.
Payment by paypal

I'm going through my Luxman L58A amp schematic and have cone across some transistors that are known to cause problems, just wondering if in the position there in it would affect the amplifier gain (Hfe)

Q205, 06, 07, 09, 10, 11

I'm ready to finish my 2.1 garden system (MkIII). The first two incarnations were powered by laptop bricks. I want to use a different power supply. I'm just checking that if I connect pins 2 & 3 of the input connector to the mains it'll be live (I don't need to connect the remote).

250w / 24v

Hello. Since I started trying to learn about diy audio, my learning has been constantly restrained by my ignorance of math. Many of the texts I try to read through presuppose knowledge that I just don't possess, and inevitably, I get confused. So, I have decided to take a step back for the time being and try to develop some foundational knowledge. I just ordered the book Basic Mathematics by Serge Lang. It seems like it focuses mostly on algebra, although apparently it also gets slightly into trig, and even has some stuff on proofs. Does anyone have any other recommendations for books that I should read so that I may more meaningfully engage with this community? Maybe a book specifically about electronics? Or would such books also presuppose knowledge a layman might not possess? Thank you.

Good morning everybody.
Can someone tell me this amplifier din connector pinout?
I cant find this..

Morning all,
Just plugged my Sondex preamp back into my second system and it sounds distorted , it was fine a few weeks ago , it has been in the garage and it’s getting cold here.
Also does anyone know what the switches could be for ? ( switches L & R on the circuit board)

Greetings friends. Having recently figured out how to hook up an oscilloscope+signal generator to an amplifier, I'd like to analyze my daily listener. So I put the sig gen in the 3k-65k range and put the scope on the 4-ohm resistor across the output terminals. Get a wave that looks like this:



As you can see, there's major rounding of that leading edge. What gives? Amp has no feedback so there's no phase lead cap to adjust. Here's the schematic:
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Anything I should look at?

Thanks!

Hello everyone,

For sale is a single EML 45 solid plate. barely used coz i dropped and broke the other one.

Asking $250.

Buyer pays shipping and PayPal fees.

Hi All
Does any have a copy of the XO circuit diagram for Sansui SP-X11000 speakers?
Thanks in advance.

Doug

As per title, I was wondering about the effects, if any, of the aging of the LED references. I have a vintage amp that has bipolar BJT current sources with LED voltage references (see positive and negative rails schematic snippets below). These are your garden variety 5mm cheapo red LEDs. They are not run very hard (3.6mA).



I live in an imaginary world where licorns thrive and silicon junctions are eternal, but I guess they must have a life expectancy. The amp is currently open on the bench and I note that the LEDs are quite dim - much dimmer than a new red LED passing 3 mA; some have almost an unoticeable glow. Furthermore they are not all equally lit between halves of the bipolar supply on each current source section. Note that the transistors including the power finals and all other diodes don't seem to suffer aging...

Information on these old amps is scarce but once I stumbled upon an article on upgrading a member of the same series and vintage of amps, which has basically the same circuit but with scaled-down components and power (I have an exemplar of this model as well). The author, which apparently had a good deal of experience in restorations and upgrades, wrote that he systematically replaced current source LED references.

So I guess I should too, or was he over-zealous?

so I bought some speakers where the crossover need some fixing.

While in there I saw that the caps used were electrolytics and wants to replaced them with film caps. My issue is the size of the caps used.

1. 100uF 100V
2. 22uF 100V

My issue is the 100uF one. that's a HUGE cap.

I'm thinking that maybe this can be installed off-the-PCB using wire to extend the leads? and perhaps using some zipties to keep it in place?

Also, is it worth replacing the cement resistors with something like Mills wirewound?

Thanks a lot of the response!

It appears that there is quite the shortage in IGBT's at the moment, with wait times as long as 9-12 months!
I've used all my stock up of HGTG30N60A4D 's, which are used in many pro audio amplifier SMPS's. They are designed for high frequency (100khz, 200khz at lower current)

HGTG30N60A4D was made obsolete a few years ago, I currently stock a pair of IXGH48N60C3D1 , these look like they should be a suitable replacement given the switching frequency used of 40kHz in the amplifier I am currently repairing. Would somebody be able to compare these two devices and see if I'm on the right track in terms of these being a suitable replacement?
However, the IXGH48N60C3D1 are also out of stock, so once I use these, i'll have to find another replacement for future repairs.

Can anybody recommend replacement IGBT's for the HGTG30N60A4D? The Replacement must have a build in Free wheel Diode.
I found this one from On Semi that is in stock, FGH75T65SHD-F155 , looks similar in terms on turn off delay times, gate charge and Qrr. It seems there is much more range in the 650v IGBT's than 600v IGBT's.
Is there much of a drawback in using a 650v IGBT in place of a 600v one?

If anybody could help with suggestions that are in stock at Mouser / Digikey / RS Components, It would be much appreciated.

I have 16 each of the Carnhill VTB1148 Output transfomer and the VTB9045 Mic Input level transformers for sale.

They are brand new in the box, never been used. Bough them for a project which I have never gotten around to starting.

Asking $40 for the output transformers and $50 for the input transformers and free shipping to lower 48 via USPS.

This is the version of the version of the kit that comes with all of the electronics (aside from the SMPS).

"This LX Mini XO Kit contains the PCB, 16 matched JFETs, 16 matching resistors R13-20, R35-42, and all the other PC board parts mentioned in Nelson's article (Trim potentiometers, resistors and capacitors"

It is in perfect condition and currently sells in the DIY audio store for $100.

$60 includes shipping the United States.

Hello! I have a weird “issue” with my no29 power amp. When I set off the power of the amp the led never shut off totally. It is always light a little as you can see in the photo. Although there is no leak in sound when the amp is off. What it can cause that issue?

FS are 3 pcs Beckman SP-352 untested NOS.

Want €50 for all three, otherwise please PN me.

Shipping fees according to post.at (ship from Austria).

Paypal preferred.

I have acquired about 400-500 brand new Rotel Transformers. Rotel used to...or maybe still does im not sure...used to make their service centers buy and stock a certain number of products, boards, cables, connectors and...Transformers...which never fail. so over the years these would just pile up. From my previous experience selling transformers, there hasn't been much interest in stuff for solid state gear...BUT. before i send these all off to scrap...would anyone have interest in any?? if it is worth while i can post some. I have transformers from most of the more recent products in the last 10 years. preamps, power amps, toroids, EI core, R-Core potted. etc etc....problem is. I have Rotel part numbers and SOME say what they were for RC-1550, RSX-xxxx, RA-1555, A-12 etc etc but I don't know what the voltages or current ratings are for any of them. a person would have to research them and I do not have the time nor the desire to do so for a $10-$20 item.
OR, I could do a mystery box...$50 and i send you a box of random transformers and you figure it out.
I just HATE scrapping perfectly good parts! and Rotels transformers were REALLY nice! the canned potted Preamp transformers are really really nice units. and i just do not have the space nor the time left in my life to deal with them all LOL
SO....any interest? any takers? I would LOVE to make a one time deal for all of them! I have a ton of other Rotel parts i need to deal with. boards, chassis covers, etc etc
I am in minnesota and I can ship as I have time between family obligations, biz, work etc.

ZC

I would like help to work out a protocol for rapid stress testing and possibly bedding in a 24bit 384kbit R2R SS DAC.

In the rare event a DAC is going to fail I want it failing asap. I also want to test if playing in makes any difference to perceived sound for better or worse. Id appreciate this thread being a protocol thread. If you want to argue or speculate about the actual reality of burn-in please go to https://www.diyaudio.com/community/threads/burn-in.328225/page-9

Please share your ideas on how to maximise rapid burn-in:

• Is it good to have a power off time to form caps and do expansion-contraction stress testing?
• Is white noise with high frequencies going to speed up processing?
• To activate all components is it necessary to play files with full volume range covering all the bit depths eg white noise from -140 to 0dBFS?
• Will a low resistance dummy load appropriate stress the output stage?

Please critique the approach below:
1. Play for 11 hours on and 1 hour off for a good ten days.
2. Play a special white noise 24/384 file at -140dBFS to -0dBFS, doing 2Hz-96kHz, alternating with a 2Hz-96kHz sweep
3. use a low value resistor as a dummy load on the output, to stress the output stage and get the current flowing.
4. A/B with a known stable DAC before and after. Ideally have two of the same DACs, burn only one in and listen blindfolded and A/B before and after.

Thanks.

Fully active 3 way speakers, with a 15 sub.
Tweeter GRS RT2, 3k high pass
Mid Lavoce WSN041.00 4" Neodymium Woofer, 250 high pass to 3khz
Woofer LaVoce SSF082.00L 8" Paper Cone Subwoofer, 60 hz high pass to 250 hz

Help,
Just finished building a set of bookshelf boxes and I'm having second thoughts on the chamfer cut I did on the back side of the driver hole.
The baffle is 36mm thick, the driver hole is 150mm in diameter and the 45 degree chamfer goes down about 15mm, so there's about 20mm inside the hole that is not chamfered. Do you think this is enough for the driver to breath or should I remove more wood?
The 2 options that I am thinking about are 1) Use a Dremel tool and remove more wood, 2) lining the inside of the hole wall with weather strip or felt, I've read that this might do the trick and reduce reflections.
BTW, driver is fullrange, if that makes a difference.
Thanks

I was given a grubby but serviceable copy the 1933 RCA-Cunningham radio tube manual (RC-11) and was quite looking forward to browsing it. And then I looked at the back cover and saw the distinctly phallic arrangement of valve-and-trademarks surmounting the National Recovery Administration logo and motto: "We Do Our Part".

Now I'm nervous about what RCA-Cunningham might have meant by "doing their part" and what I might find between the covers - surely not a centrefold?

I haven posted for some time.

I am wondering if an Hypex FE253 plate amp would drive Gale gs401a’s and if so would the sound differ greatly from the class AB I’m running at present.

Thoughts Please.

I'm trying to design some pcb's for THT LT4320 rectifiers and I've come up with this design. To try to get plenty of current I've made 2 AC and 2 DC planes. It ends up with a good amount of surface area. My thinking is that:

• The DC planes do overlap, but any capacitance generated between the DC planes is fine, because we already need capacitors here for the LT4320 to work well (as per the spec sheet)
• there's no overlap on the AC to AC side
• There is a bit of overlap from DC to AC, is this a problem?

Does anyone have any feedback? Is this a bad idea for some reason? Do I need to do 2oz pcb for this?

Does anyone know how to calculate the difference of two dB-levels? Something wrong comes out of this.

.meas AC res20 FIND MAG(V(Vout)) AT 20
.meas AC res1k FIND MAG(V(Vout)) AT 850
.meas res2 PARAM MAG(res1k)-MAG(res20)

strg-L: ->

res20: mag(v(vout))=(-3.30797dB,0°) at 20
res1k: mag(v(vout))=(-25.5767dB,0°) at 850
res2: mag(res1k)-mag(res20)=(-4.00405dB,180°) <---- -22dB expected

Hi all!

This is a bit of a 'lazy/cheap/mad' idea of mine that on paper looks fine, but I was wondering what the reality was - has anyone tried this?
I've two spare but fettled Maplin MOSFET amps that I want to pop into an old Sony TA-F6B hulk (I was never really comfortable with the PSU or BJT power amp), and I have two options:

Plan A:
Use my existing spare 300VA toroid + a new softstart relay + resistor (ebay £4+) with new capacitors, perhaps twin bridges to separate the MOSFET supply and the amp PCBs...
..
OR Subversive plan D:
Buy two cheap 48V SMPS PSUs, hopefully quiet ones - yes, it's a lottery, but perhaps the POEs will do, and hook together as a bridge. That in theory gives nearly 300W too, and saves all the bridge and cap work and cost, but at the expense of separate rails for the OP transistors. In a way this is sort of more in the spirit of the original...
..
Plan Da:
A variation on this theme is to use a small 48ish Vdc split analogue supply for everything else, perhaps +/-35-40V would do as it's all regulated down to +/- 30V anyway, and the POEs just to power the MOSFETs themselves (the top source and bottom drain).
..

All thoughts welcome - thanks in advance! 🙂

For very modest output of around 85dB, it has been pointed out to me that some hifi tweeters can be crossed as low as 1khz or so. And this is true; they'll do so even on the manufacturer's FR charts, at 1watt. Though the lower distortion ones (in my area of the world) are quite costly (e.g. scanspeak D3004, though the SB26 looks reasonable for less) and of course they are being used outside the expected range.

So it has me wondering about compression drivers with small 1" throats, yet a much bigger diaphragm. Even some modest ones would do it 'very' easily, with a tiny fraction of a watt and without any need whatsoever for horn loading at a mere 85dB or so. I'm also happy to use DSP/EQ to flatten and smooth their frequency response. However this is for a compact speaker, there is no way that a big <1khz horn or waveguide could be used; I'd be looking at something much smaller - essentially round-overs, just big enough to avoid bad edge diffraction. I accept this doesn't control directivity, but listening near-field I'm mostly interested in the on-axis results (within reason).

Can anyone help me understand how a compression driver used like this would compare with a hifi tweeter?

Just to anticipate: Yes I realise there are AMTs and full-range/mid-tweeters etc. etc. that would cover the <1khz and higher range. But I want to ask the question if, at a low SPL, compression drivers are also a viable and possibly even better option?

Thanks,
Kev

I'm planning a build over Christmas for a workshop Bluetooth speaker build around the Bru5 amplifier which has dsp. The brief is it's a fun project and not expecting hifi. It's gotta go load so can be heard over the machinery. The two channels I would like to run a FAST arrangement in mono if the software allows this. The full range will likely be the faital pro fe22 that often get mentioned but I'm not sure what subwoofer to go for. I would like it to be sealed due to saw dust. Something that doesn't mind being EQ'ed. Size of the cabinet and driver isn't a concern within reason but it's a budget fun project so not silly money. The fr driver is £20 the amp was £30 so if I could get a sub for £50ish so I've spent £100 that would be great. (Free wood for cabinet)

I am trying to find a speaker design to build, being capable with my paws but not being a speaker design Guru.

I hear good things and like the look of Curt and Jim's creations, but a number of the designs I like are either just too big for the room they are intended for (Statements / SII), or there are drivers in them that are no longer available.

I like the Finalists which are an older design, but I have recently discovered there is an update to them - the Travelers. From what little I can glean they would be near perfect for my needs. Trouble is the only place they and their plans seem to be available is Meniscus. Or rather was. I hope they enjoy retirement.

I can probably find the drivers and other hardware, even here in the UK / Europe, but without the plans for cabinetry, crossovers, a definitive list of drivers etc I am stopped before I even start.

So does anybody know where I could get the plans for the Travelers?

What do you all use when the design has a DIP footprint and the manufacturers and reputable suppliers only have SOIC? I know there are adapters but my eyes are 63 years old and I do not want to buy a rework station.

I need a driver for AKG702

Can the 8900 be ordered preasembled without the Alps volume pot (plan to run it directly from IFI IDSD Pro)
If that’s possible, how much will it cost, shipped in the USA, as reviewed “Full Monty”by HA in the July issue of Stereophile (Lundhall+full AN upgrades+anything else that’s on VK mind for betterment of sound and life), with tubes other than GE?

Cheers

On the desk I have the above mentioned FM tuner from Linn.
There is an oxidated area on the front PCB arround the 3V6 NiCd accu (memory cell) on the front PCB - go to the attachments so as to mpost #7 and #9 under
Linn Kairn repair
But the actually issue is the fact, this device has not been used for about 20-25 years. This means, that the electrolytic capacitors behind the rectifier must be soldered and reformed by a high-impedance resistor - go to
Reforming Electrolytic Capacitors
is there an other methody of this without the need to unsolder the big blue BHC caps ?
Thank you for advices.

I had a Sundown SFB-8000D amp come into the shop yesterday that wasn't giving any output. The guy who brought it in said he bought it off some crack head on Facebook marketplace for a good price, but bought it knowing it was broken. Apparently the original owner was cutting out the transistors to the right of the ones pictured whenever one would blow and take the output out. Best I can figure he also cut the legs on the S5 and S6 ic's as well and soldered them back together.

My problem is Sundown decided in the factory to remove the original markings on the IC's and now I can't figure out what the transistor is supposed to be. Looking this forum I managed to find the missing transistors (which are labeled D1 instead of having part numbers) are IRFP90N20D and the driver IC's (which are also burnt up) are Irs20957s.

The transistors in the photo aren't testing faulty I just don't like the idea of taking all the time to source the missing and blown components and leaving these in in their current state.

I appreciate any and all help.

Hello 🙂 I am seeking advice with my yamaha a-1000. I am not sure if it is just my piece or it is standard behavior of this amp, but the sound from the stock preamp is really not nice. It has a really flat sound on mid/high frequencies. But the situation is completely different when I put the input signal directly to the main amp. It started to produce a really nice sound, not boring, not liveless, not flat. So I guess that is something not 100% allright with a preamp. I changed 4x caps (highlighted) on the preamp board. Also cleaned the DIRECT switch, MUTE switch and did measurement on other signal switches, all looks good. Both channels have the same ** sound, so I hoped that IC M5219L is not good, so I swapped it for another(from the main board) but unfortunately it didn't help. Voltages on IC are correct.

Input voltage to the preamp board is +21.5V and - 18.9V (should be +-22V). But I guess that this is not problematic because this is also voltage supply for the IC on the main board (main board sounds great, also on DBT when voltages are even lower).

What else should I try ? Change M5219L for something different (opa2604) and hope that will be better ? Throw a preamp (they call it flat amp, yes I agree 😀) in the trash and use just the main amp ? 🙂 Thank you for your ideas 🙂

For sale are a set of pcbs to build the the xa252 or Plethora of pinjatas amp with a single pair of outputs. 3 main pcbs, 5 output pcbs. You have a spare for each pcb.


Price SOLD

Hello I want to build a new amplifier using ECC83-12AX7-6n2Pev (all equivalent) and one 6L6GC in SE with GNF (no others please, because I have a lot of them).

I never played with mu-follower.

Can you please check if the mu-follower schematic is correct and which values you would suggest (using the above tubes)

Available AT is 320VAC so I think to get 400VCC.



Second question: what about two ECC83 in series and a 6L6GC with GNF? It gives me a much lower THD% (second scheme) and a much bigger input sensitivity: should this sound better?


Thanks

This magazine, founded in 1924 by Mr. Mitsugu Tomabeji, is one of the earliest and most influential radio magazines that I know. In the early years it was Radio experimenter's magazine (Musen to Jikken = Radio and Experiments). The early publisher of this magazine was the currently brand ITO and the currently publisher now is Mr. Seibundo Shinkosha.
https://web.archive.org/web/2008101.../english/corporate-profile/history/index.html
In general this magazine is a DIYer magazine and is very technical but is full of great articles on electronics and speaker design, room acoustics, audio history, as well as reviews, news, show reports, etc.

Very great similarity I note to the french magazine 'l Audiophile from 1977 until 1989 - go for table of contents to
http://6bm8.lab.free.fr/Documentations/Revues/Audiophile/index-1977-1988.html
The table of contents (INDEX) I can get about compact disc's:
CD1: 43 editions from 1977 to 1988- Part I:
go to
https://web.archive.org/web/20100518094713/http://nicolas.davidenko.perso.sfr.fr/revue/revues2.htm
for information in detail. Please note, the kind of the magazine is changed from 1989 (now a normal testing magazine like "Stereophile"
CD2: 32 numbers from 1989 to 1995 - Part II

I want to have all articles about solid state pre-amplifier and power amplifier topologies published in this MJ magazine.
Where I can get table of contents about the MJ Magazine for download or as CD-ROM and what about translations in various other languages?

here various URLs:
http://www10.big.or.jp/~dh/sakuma/index.html
https://web.archive.org/web/2008120...ck/Texts/GeschlosseneGesellschaft/2-5-10.html
JSTOR: An Error Occurred Setting Your User Cookie
??¸ ?'75 Stereo Technic ???????? McIntosh/JBL/audio-technica/Jeff Rowland/Accuphase/?/?¾?????
??????/TOP???
Subscription information for "MJ"
http://www.fujisan.co.jp/Product/244
Patent US4079333
http://www.diyaudio.com/forums/swap-meet/129395-mj-audio-technology-magazine.html
http://www.diyaudio.com/forums/everything-else/136060-why-i-buy-mj.html

BTW - you will get very interesting cover images about google by follow japan keyword:
"無線と実験" (english: "Experiments with radio")

I'm offering theese capacitors, they are all NOS siemens, for sale, minus the cabinet, I'm unsure about quantity, but all drawers are like photos, can on request take more photos.
Asking price 150 euros, or trade with a lcr meter, DER.DE5000 or similar quality, fried my own by accident.
EU only.

Hi,

My bookshelf tweeter was not working fine so i tried replacing it with same specs but instead of 2 inch I replaced it with 2.5 as my cabinet had more room also 2 inch was not available at that time.

What I noticed is my old tweeter had closed back means spider was not visible, were as this tweet has a open back i can see spider.

So will it make any issue like, moreover

woofer is in different compartment there will be not much air pressure only vibration is a issue they might interfere with my tweeter or not i don't know.

If it is bad so I can replace with closed back one or return this 2.5 inch tweeter and try finding closed back tweeter

Thanks in advance