Can anybody identify the small component that is on top of the 3.3uf capacitor? It is in parallel with that cap for the tweeter and the brand looks like a Z and the component is labeled 2700J. Maybe it's a bypass capacitor but I really can't tell. I can't find the schematic for these speakers (Realistic Optimus 900).

Hi
I'm working on a efrp 300 redundant ATX power supply . But I couldn't
Run it . Did any one know how to start this type of power supply
Without server?
I want to make a battery charger for my wheelchair .
Thanks a lot.

I’m actually owner of a subwoofer MA BXW 10, and I’m looking for un upgrade.

Looking in the local market I found:

Velodyne HGS 15 thx, used
Audio Physics Rhea II, used
Audio Physics Luna, new

All at almost same price.

About Velodyne I read enough, seams good, but no very reliable.

I could’t find reviews or information of Audio Physics, I heard some speaker and I have very good oponion his products.

Any one could give me more information to make a good chooise?

P.D: I wanned mainly for music, my speakers are Devore O/93

Thank you,

For Sale,
SB12MNRX25-4 pair of midrange drivers. Mounted in a baffle for measurements. Didnt see much use after that.

Price: $75

Smoke free home. Impedance plots available.

Buyers pays shipping and PP fees. (US shipping only)

Martin

I am selling my Stereo UCD400 integrated amp.

Built in a little dot T_150 case

1 Toroidal trafo 400VA
4 x 10.000uF Nichicon caps
2 rectifier bridges

High end preamp module with 4 inputs, screen and remote control

Asking 400 Euros - including shipping costs.

After updates to my speaker wires, amplifiers, preamplifier, and adding a new TT and cart this year, I was pretty sure my old Denon DCM-440 CD player was the weak link in my system.

Today I installed a Topping E30 DAC. Tonal balance is largely the same as it was, though the bottom end is a bit tighter. What immediately struck me was an improvement in spatial separation and depth. It's more reminiscent of the sound stage I get from vinyl....not quite the same resolution, but a notable improvement. Definitely recommended if you're considering an upgrade to an older CD player.

Guys, I'm new to headphones but would like to dabble in HP amps.

I know there are many different headphone impedances, from 32 ohms to 600 ohms, maybe even more.
What sort of signal levels do these things want to make your ears bleed? I see numbers of xx mW but I guess it depends a lot on the headphone impedance.

Any pointers?

Jan

Hello,
I have the Dual Mono boards (2 PSU and 2 amplifiers) from Brian Gt.
Finally I decided to buy only one Transformer 2x25V 300VA.
Does it make any improvement if I use the 2 PSU boards instead of one, with only one transformer ?
each PSU board have 2 caps of 10.000uF.

Regards

Armindo

I have -12v dc on the mosfet legs that should have 0 in the output section

I've got this vintage MA20 Roland studio monitor and the driver is chirping and distorting like a cricket 🙁

I've tested out of the unit on another amp to check it's definitely a faulty speaker and it is. It measures 7.5" diagonally from mounting hole centres. 4ohm 15w printed on the back of the magnet.

Can anyone recommend a suitable replacement available in the UK/EU?

Thanks in advance.

Hi all! I've built a couple of sets of speakers before, and was curious to try out a full range Transmission Line design. I have a pair of the "NSB" speakers from Parts Express about 15 years ago (!), and thought I might give them a shot in a TL.

I was looking at similar designs and came across the Woden BabyLabs designs. In particular, the "Shrike", which is designed for the 4" Fostex FE103-SOL.

I plugged in the TS parameters for the NSBs into the Leonard Audio TL design program, and attempted to enter the design parameters for the "Shrike" cabinets:
- Start area: 26.25" (5" x 5 1/4")
- End area: 8.53" (1 5/8" x 5 1/4")
- Length: 33" (11" + 11" + 11", the internal height of the cabinet)

First time using the software. Did I do that right?

The output isn't so bad. +/- 1.5db down to 59hz, F3 of 57hz but -10db by 51.5hz. The box is about 10L/.35cu.ft. Using WinISD the driver looks better in a ported box tuned to 55hz (2" port 6.5" long), with an f3 of 44hz and f10 of 39hz. But I thought I'd give the TL a try.

I know the NSB drivers aren't great. I'll probably try treating the paper cones by spraying them with a few light coats of lacquer as others suggested back in the archives. Plus side is that I should be able to build these cabinets with a handy panel of 1/2" ply and an afternoon at the table saw.

Any thoughts?

Sold

Hi I’m hoping someone can help. I have Orion amp that has a burnt cap that I can’t read the value of. If anyone possibly has a picture of the circuit board available it would help me loads.
Cap location on board is -C294- if that helps.
Thanks

Hello!

I have seen some mount a driver behind a slot or a hole which the driver then plays throu, is it possible to predict the response from this? What happens if one using many holes in a line or a circle?

Would it be possible to use this technic to build a coaxial driver to minimize tweeter output reflecting info the woofer cone?

Valve CD player in excellent condition
Original owners manual included

Collection only ( sorry [emoji52] )
Milton Keynes U.K.
£350

Hello, I have a question about Audio isolation transformer breaking ground loop. It seems reasonable since the transformer provide another grounding point instead of the common ground. But the other end of the circuit, maybe it is a preamp or power amp, require power, so we have to connect signal ground to the power ground, so it may bring it back to the ground loop?

Hi,

I'm trying to subtract the volume within the cone and baffle cut-out from the throat section of my TH (still in the design stages). I would like the volume within the enclosure to match what was simulated in Hornresp.

I read in the THAM 15 tread that this is called 'cone correction' and saw that pieces of wood was used in the throat section to displace the volume taken up within the cone.

However I was thinking of reducing S1 thru S2 to compensate for the additional volume within the cone and baffle cut-out, by doing this I could simultaneously increase the mouth size to compensate for the displacement of the rear of the driver also (my folding scheme is same as the THAM 15).

Would this work or would this just increase the compression ratio? I really don't want to risk damaging the driver.

Thanks.

Hi there, I own old JBL LSR25P in great condition. Its amplifiers are made using LM3886 and the enclosures are from solid metal, so the sound is rather amazing.

One thing that really bugs me is that there must be something wrong with the electronic - I recorded the sound in attachment playing solid 50Hz from the speaker recording with my measurement mic and then high pass above 50Hz so only the parasite sound stays in the recording without the 50Hz...

I am absolutely positive it comes from the electronics, because one speaker does it on 50-60Hz and one 60-70Hz and when i switch the drivers between them, it stays the same - th one that did it on 50-60Hz still does it on 50-60Hz even with different driver...

My question is - is there something I can try to change in electronics to make it go away, can this noise be comming from something specific or is it hard to tell? I am no electronic engineer, I know my basics and I can build amps frmo kits but when ti comes to debugging the amp problems I am lost.

Its really very sad - those speakers are so great, yet this makes them hard to listen to electronic music or any bass intesive music, because the noise can make itself pretty pronounce there... apart frmo that they sound great on any other frequencies, its only the very low bass producing this...

here is the service manual with complete schematic if that can help to anyone trying to help http://www.jblproservice.com/pdf/LSR Series/LSR25P.pdf

Hi,

I'm planning to replace the electrolytics in my mixing desk power supply. It's a Studiomaster 20 channel, 16 bus desk from 1986 and it now has a very quiet, but noticeable background hum. I thought that replacing the main filter caps would be a good place to start.

The power supply is external and has +-15V rails for the audio circuits, single +15V rail for the displays and +48V for the phantom power. The main filter capacitors are the old, light blue, type with solder tags, clamped to the casing and wired together with thick bus wire. There are also several smaller radial electrolytics on the board.

I've got a few questions about replacing them. Firstly, do you think it's necessary on a board of that age? I have replaced power caps on noisy amplifiers newer than that but have older pieces of equipment that have never been touched and are still quiet.

Assuming I do replace them, the physical size of the capacitors is a bit of a problem. The way that the connections are made, with a network of bus wire, means that the shorter packages will be a bit of a pain to fit. Has anyone come up with a good way to fit newer, smaller capacitors into older power supplies? The main supply caps are currently 6800uF. Using a larger value would give a physical package size more like the old ones. I've seen people do this before but I'm not sure if it's advisable or not.

Any tips would be greatly appreciated!

Thanks,
James

Good morning
Has anyone built a sub woofer plate amp? I know thy're easy to buy and in some cases quite cheap, but I thought it might be an interesting project if there's a schematic available.
Regards Johnno

I own two attenuators which both display volume with 7 segment displays. I use Salas I-Select for source selection but I thought that it would mate great if there was a 11 segment (7 is insufficient for letters) for source. Anyone know such a project ?

My previous McIntosh preamp along with my friend's BAT preamp have such a feature.

IR4301 MONO amplifier module,
Good for 6'' to 8'' speaker.
Power supply: +/-24 to +/-32 dual supply
Max output : 120W @ 4ohm with 1% THD+N
input: RCA with internal switch
Output+ daul DC supply : 5.08mm screwable euroblock
Toggle switch for mute/unmute the amp.
Size: 45x90mm

All above features you just need to pay $19.9usd without shipping.

2x30W TPA3118 Powered speaker plate:
Good for the 5'' speaker unit;
Input: Dual RCA (with internal switch); & CSRA64215 BT4.2 module, support APTX,APTX-LL
RCA sensitivity: 350mV
AC Power: Universal AUX + Main dual smps to support the deep sleep feature.
Size: 175 * 100mm

Please PM me if u are interested😀😀

What material do they use ?
i noted that they are very very similar to scan-speak discover (economic range)
the top seies of scan-speak use transparent domes, infact can be seen the texture of the silk.
sb instead seems to use vulgar plastic material, also the economic and opt renges seems to use the same material

your contributions are welcome

I accidentally connected the outputs of two amplifiers together. The Hitachi is toast, and will be remember fondly.

The Sony plate amp is wounded. It only has high-level inputs. The subwoofer still works but one channel on the pass-through outputs has failed. A speaker connected to this channel is very quiet (sounds like it's been shorted).

What am I likely to have blown? Is it worth repairing?

I was given this valve amplifier, and upon receiving it I had a look around it for a brand, or a model name, but I couldn’t find anything. It has a pair of metal 6l6s in push pull configuration, two az31 rectifier tubes, an Ef37a and a metal 6sc7.
It has two microphone inputs and a gramaphone input, leading me to believe it is a pa amplifier, but it would be nice to find out who made it and get a few schematics. Any help is greatly appreciated, thanks very much.

I’m a learner and posting here again becauno answer earlier (and jumpy inguess)..
se i’ve tried to google for the “issue” I have and not found anything, and really wanna solve this. so here it goes;


In my Nad 116I added an extra PT (actaully 2 new transformers of 2x25v sec and the one for audio section slightly larger) for logics and what i can understand this is a half wave rectifier curcuit for logic supply but is this correct how to implent a second transformer?
The whole mainboard share the same “ground” and the audio section has its centertap to this “ground” but will there be issues if i use the same “ground” for the new pt? So basically same “ground” for both pt’s? Or does the ground or zero or what we call it need to be separated?

See my drawing please. The smaller PT i’ve paralleled to give 1x25v.

I’ve also added an extra fuse on that new pt but unsure what right fuse will be. Current draw over the 2.2R fusible res was max 100ma. But this currentdraw only count what the 7805 draw or? Not total?
Added a input mainfuse also to new PT and its now about 250ma. There was only those 2x800ma on the secondary before.
I’m guessing now that they are too big now when the load isn’t that big over that part of the curcuit anymore.
I’ve tried and look for answer also how i can measure currentdraw from each curcuit so i can fuse them properly.

Everything is hooked up and using only one rectifier diod now.
Just lack the courage to push the button because it feels somehow wrong what i’ve done.

Thx for your help.

12" driver,
that I cant push it down only move it up,
do you suggest to replace it surround foam
The only issue that I not like to do is remove the dome/cap or try to balance it on gluing.

Hi everybody,


"Poppy" is how I would like to be called. I just got an PL504 somehow amplifying audio and want to end up with a proper stereo push-pull amp for a small living-&bedroom. Please let me take this chance to continue by introducing you this guy instead of myself and I swear most of you will agree that these were the worthiest minutes on Youtube you ever spent there:

link removed.

This is an amplifier, you could say, that amplifies what has to be. I just saw this by myself a minute ago and not only because of being from Germany: I am impressed by this guy but much more shocked and so will be you...



Poppy

These are fully assembled three ZA5.3 MTM In-Wall speakers. One of them has the tweeter turned 90* for use as a horizontal center channel. They were built by me and used in my home for about 2.5 years. I built them from the Madisound kit linked below and from Parts Express In-Wall baffle kits that are no longer available. All told after parts and shipping on everything I think I ended up at about $625. They were painted to match my wall color and mounted in my living room as shown. They could easily be repainted white or any other color (just remove the parts first).

I've had to remove these because we hand some built-in cabinets installed around the TV and I'm going to have to move to bookshelf speakers. I would rebuild these into boxes, but I just don't have the time I used to have with young children.

I'm asking $350 for all three plus shipping, which are based on ground shipping estimated from FedEx and are as follows:

$50 for the complete kits shipped to US East Coast.
$90 for the complete kits shipped to US West Coast.
Some amount more than $90 for international. If you are serious I can get a quote.

Madisound Kit:
https://www.madisoundspeakerstore.com/mtm-speaker-kits/zaph|audio-za5.3-mtm-pair/

Madisound ZA14W08 Woofer:
https://www.madisoundspeakerstore.c...aph-audio-za14w08-5-aluminum-cone-mid/woofer/

Madisound Vifa Tweeer:
https://www.madisoundspeakerstore.com/hard-dome-tweeter/vifa-dq25sc16-04-1-titanium-dome-tweeter/

Zaph ZA5 Design Page (it's the last speaker on the page):
Zaph|Audio - ZA5 Speaker Designs with ZA14W08 woofer and Vifa DQ25SC16-04 tweeter

Zaph ZA14W08 Design Page:
Zaph|Audio - ZA14W08 Woofer

Dear all,

based on this Francois G's post:
https://www.diyaudio.com/forums/tubes-valves/72536-el84-amp-baby-huey-post6132583.html

and on these gingertube's suggestions:
https://www.diyaudio.com/forums/tubes-valves/326920-el34-baby-huey-amplifier-post6144401.html

I would like to open a thread for a group design for a more powerful amp that can be used for Hi-Fi or as a bass amplification.

The Hi-Fi version will have standard screen supply, while the bass amp version could implement the Mesa Boogie "DynaWatt" trick to let the screen supply sag a bit during transitories. I've used it with EL84s and I liked it.

I attach here a first sketch of the amp with 6550s with 600V on plates and 300V dedicated UL taps that will supply the PI too.

Only one bias&driver is sketched, but there will be one for each PA tube.
I've shown that the power supply for the drivers must be approximately ±3 times the bias voltage of the PA tubes, but I don't know exactly how much to expect in this configuration. Will the PI swing what is needed?

Raa should be 4k2 for each pair, so 2k1 in this specific case.

I would like to have your feedback on this, and then how a cheap and powerful tube like the GU50 could be implemented, being on paper not the best tube for this purpose (see this gingertube's post to know why: https://www.diyaudio.com/forums/tubes-valves/72536-el84-amp-baby-huey-post6132342.html )

Thank you all in advance,
Regards

There does not seem to be a recent conversation on this subject.

I live in Arlington, Virginia, and would like to have a cup-o'-something with fellow fanatics -- wherever your slice of passion is on the audio perfectionist pizza.

Not a club exactly -- just common interest conversations; let me know here on the forum, and then we can do PMs for specific plans. Looking forward to replies . . .

Hello! I am interested in buying Hypex Ncore modules NC XXX MP series or plate amplifiers from Fusion Ncore series for stereo application. New or used. Seller has to be from EU and have paypal, i will pay through paypal. Thank you.

Help to simulate double bass reflex

Hi 🙂

Is there anyone who can help me to simulate a double bass reflex to Lowther PM8A 15 Ohm with silver voice coil?


Fs 58 Hz
Qts 0,36
Vas 46,2 l (1,63 cubicfeet)
SPL 95,5 dB 1w/1m
Re 12,7 Ohm
Qes 0,39
Piston diam 164 mm (6,46 in)
SPL 93,5 dB 2,83 V
CMS 0,74 mm/N
Le 0,47
Qms 5,1
BL 11,1
N(0) 2,2%
MMS 10,3 gr

Hi,

Looking for the pin out for the ES9028Q2m 32 pin chip.

I realise there is NDA to release, i have asked ESS. no response so far.

I don't need the data sheet simply the pins requiring power, VCCA, AVCC, etc.

any info on this would be much appreciated.

I bought 4 of these BT transmit/Receive modules from fleabay, they all work great except for one, it sometimes sounds like it's a 33rpm record playing at half speed until I click the one button that it has so it reconnects. Then sometimes the audio stops for about 5 seconds then comes back for 10 seconds and repeats over and over again but then I can't turn it off? I have to wait until the battery has died then charge it back up again. I contacted the seller, he said to make a video of it and send it to him but I explained to him that I'm 67 y/o and I have no idea on how to do that? So he said to post it to China. lol He wasn't listening because when it gets there the battery would have run out and it would be Ok to go again for a while and I can't see him taking the time to test it? Would I have any success breaking the cover open to have a look and see if a wire is hanging off or something?🙂

Good morning everyone. I am looking to get my final measuring tool for my driver's. I like the Omni Mic you use disk which I don't mind? If I get Rew I need a external sound card and microphone stand, Omni mic, microphone cord, and phantom power supply. I have a Windows 8 computer. Please let me know what you think? Cheers Jeff

I have no experience with large coax drivers but thinking they might be a good solution for my need of a narrow dispersion hifi loudspeaker, but do they have a good midrange and treble?

I think all coax drivers i have seen has more or less poor frequency response linearity, this must be heard as coloration i believe, but can they offer good detail?

Eminence 12cx looks like a cheap and popular driver, but what about sound quality for a modest output level home hifi setup?

been listening for about 4 days now and very impressed with the stability and sound quality 🙂
Had a look on ebay for a case for the pi and tone board but not seen anything i like
loads of stuff just for the pi but nothing you can fit the tone board into
I dont just want to chuck it into a ally box
i will be building a power supply internal or separate to the streamer and i have ordered a re wireable usb A plug so i can shorten the usb cable supplied by Khadas and leave the power un connected so it can run on a separate supply without removing anything on the tone board .
any ideas ?
20200522_095933 by glenn jarrett, on Flickr

In between trade war tariffs and COVID19, there has been some difficulty in getting magnets.

I want to thank everyone for their patience, but magnets are here. Betsy’s should be shipping At the end of the month.

Best,

Douglas

Ok so i got 2 of these 2301 amps i bough broken. After some parts around, i got 1 working. The second one had blown ps fets, gate resistors, ps drive transistor resistors, a shorted diode that i think the factory installed inplace of a rail cap and the inductor seemed to have some heat damage and a prior attemp to repair.

I got the amp to idle, even tho it was running hot and producing sound. Well here is were my problem starts.

The output inductor had previously been messed with. It showed signs of overheating. Before powering the amp i took it out and compared it to the working amp. First thing i noticed is that it was installed incorrectly as if it got turned 90 degrees. I checked it for shorts between the two windings and it checked ok. Due to the burned wires, i had to cut some wiring and unwrap a turn on each winding. Checked for short and it was ok, even tho i don’t know for sure if the individual windings are shorted within themselves.
Went ahead and installed it and the amp runs a bit warmer then the other one.

Here is were it gets weird. The amp produces sound both on the scope and with a load connected. Clean and no issues up to about 8 volts ac on the wave. Any higher then that and i see the wave start to break up(not clipping). The output wave soon dissapears, the fans try to turn on and the amp starts to draw more current. I havn’t measured the current draw, but i can hear the power supply fan slow down a bit, and voltage drops to about 8.5 from 12.5.
Here it gets pretty weird. I’m testing the amp with a sound generator app. I noticed that the higher the frequency, the lower the output of the amp before it (glitched). If i use a tone bellow 15hz i was able to get 35 volts of clean output before it started to clip. And the fan was running full speed like it should with full output. As soon as it increase the frequency, i hear what sounds like a hizzing sound and my output wave drops out. I didn’t noticed any dc on the output.

Finally broke down and pulled the inductor from the other amp and put it on there. The amp runs cold and i can get full clean output in all frequencies.

Now for my questions, what are my options with this output inductor? Is this typical behavior of a shorted inductor? Did me and the previous repairer removed enough turns from the inductor to make inefective at higher frequencies. I’m considering re-winding the inductor, but i don’t want to un do the working one to measure the wires. I do not have ways to measure inductance (that i know of). Any advice? I’m doing this mainly to learn more, so i want to know the how and why.

Thanks for the help.
I’ll get some shots of the amp and the inductor here shortly.

Since I now have time to catch up on all the things that needed ... time.


I am no EE, far, far from it, but I am trying to learn at least some basics. My eyeballs hurt from constant staring at the computer screen. A couple buds at diymidwest helped me bunches building a 4s Universal tube preamp 4S Universal Preamplifier for 12A*7 Tubes. The build is here. 4s Universal tube pre — MAC/DIY While it allowed much tube rolling, it was pointed out how it was 'one size fits all' and while it might be optimal for a few tubes, for most tubes it probably was not. To that end, I was urged to optimize the 4s Universal for a single tube. The 12au7 it is.

Since I am but a newb, the cap/resistor values were suggested to me by the place I buy almost all the tube stuff, and moving the volume potentiometer to the input was suggested by everyone. This is the before and after. First diag is the original 4sUniversal, modded is number 2. After adding the 250k. of the potentiometer and 2.2k. stopper, I did not have the correct size smaller resistor to get exactly a 1m. grid leak so I had to put a 1m. in there.

First time ever doing a load line so this may not be correct, but if it is, the resistor/cap values may be way off.
For the load line, B+288v/82k+1.2k=3.46ma
For the cathode load line 2v/1.2k=1.67ma and 6v/1.2k=5ma


Way down in the lower left-hand area you will see Light green;load line, pink;cathode load line, and darker green;operating point. Also extended the cathode load line past -11v, which is the half-way point between grid voltage curves-22v and 0v. For a center bias, isn't this what I should be aiming for in an audio preamp? Using -11v as center bias and 288v yields the blue line, which I'm guessing is approximately where the load line should be?

List all possible subs that sound punchy rock. Not dhum dhum delayed sound. Smaller woofer is ok. 8". High wattage. Also speaker out would help me not buy another amp as i can use the subwoofer amp for speakers.

Would anyone in the USA be able to run a tube through their curve tracer? Nothing crazy or anything just a 9 pin dual triode. Send me a PM and I can fill in the details. Thanks.

Hello!
Refer to Visaton Grand Rogue website, the speakers can use as standalone subwoofer.

GRAND ORGUE | Visaton

"The bass part of the GRAND ORGUE, on its own without the full-range drivers, connected directly up to an active source without a passive crossover, acts as an excellent subwoofer and can be used, either singly or as a pair, to support music-orientated high-end loudspeakers and full-range loudspeakers down to the lowest bass frequencies and give home theatres the bottom end that they deserve."

Can I build the Grand Orgue as standalone subwoofer by removing those full range mid and high section? So which part should I remove based on the attached drawing?

Hello Everybody!

Looks like this is my first post on the forum, although I have had my share of diy projects in my life.



Although I just finished a home BT speaker(2x faitalpro 4fe32, tpa3116), I feel it is missing in the sub/bass section. Thus, I decided to build another BT speaker, this time PORTABLE!

Until now I have ordered almost all of the necessities, but I am still missing on the high frequency section drivers. What I have ordered:
1. Sub driver: GHXAMP Speaker 4.5 inch Bass Subwoofer Loudspeaker Mid bass Large Rubber Composite Aluminum Basin 4OHM 90dB 50W for Peerless|Combination Speakers| | - AliExpress
(I started off with the TB w3-1876s but ended up ordering this one. Cheaper, higher efficiency, approx. same volume required for a box. See the apple homepod)
2. 26650 3,7v accu for power bank. (6)
3. BMS 3s 40A for the accu. 3S 40A BMS 11.1V 12.6V 18650 lithium battery protection Board with balanced Version for drill 40A current/ Motorcycle battery| - AliExpress
4. 12v power plug: DC099 5.5 mm x 2.1mm DC Power Jack Socket Female Panel Mount Connector metal 5.5*2.1 5.5*2.5|Connectors| | - AliExpress
5. white led power button: 1pc 12mm Metal Push Button Switch High Head Ring/Power LOGO 3 220V Self reset Momentary/locking Waterproof Car Auto Eng|Switches| | - AliExpress
6. 12,6v 5a charger: Liitokala 12.6 V 5A power 12.6V charger for CCTV battery 5A charger for 12V 12V 12V battery 12V battery charger|Chargers| | - AliExpress
7. heat shrink tube for power bank.
8. DC-DC converter for constant voltage on the amp: https://www.aliexpress.com/item/32963683426.html?spm=a2g0s.9042311.0.0.27424c4doXV1OT
9. bluetooth receiver with IR remote: https://www.aliexpress.com/item/4000813876859.html?spm=a2g0s.9042311.0.0.3fb84c4dDdj3jN
10. 2.1 preamp/divider for audio signal: https://www.aliexpress.com/item/32773087353.html?spm=a2g0s.9042311.0.0.3fb84c4dDdj3jN
11. YDA138 amp board x3: https://www.aliexpress.com/item/33059299045.html?spm=a2g0s.9042311.0.0.3fb84c4dDdj3jN
(I decided on this board just by looking on the datasheets of some power amp ics able to run off ~12V. I ended up with tpa3110 and YDA138 and went for yamaha one https://pdf1.alldatasheet.com/datasheet-pdf/view/205149/YAMAHA/YDA138.html / http://www.ti.com/lit/ds/symlink/tpa3110d2.pdf)

NOW, I need the high frequency drivers.
Starting off at the Apple example with the 7 HF drivers, but without the processor, I thought I could go with 8x 1inch 16ohm paralelled drivers per channel. I am now pondering what to do, what to choose from:
a. 8 pieces of https://www.aliexpress.com/item/32817199763.html?spm=a2g0o.productlist.0.0.635776d0SaQ6OX
b. 2 pieces of https://www.aliexpress.com/item/4000029127816.html?spm=a2g0o.productlist.0.0.55671b77BVk6Ch
c. 4 pieces of https://www.aliexpress.com/item/4000027091657.html?spm=a2g0o.productlist.0.0.7bbd4db8cYXelT
d. 4 pieces of https://www.aliexpress.com/item/33041383465.html?spm=a2g0o.detail.1000060.2.6de0acb308rv3a
e. 2 pieces of https://www.aliexpress.com/item/4000272833081.html?spm=a2g0o.productlist.0.0.8b001b771qkx1u

The housing I think I will build of plywood, vertical cylinder, down oriented woofer and BR ports, and the HF drivers will be mounted on the upper cylinder wall.

Now, what do you think about the parts, and what do you think I should chose as HF drivers? Fell free to chip in with an idea 🙂

Thank you.

I could not contain the excitement any longer and had to share the fruits of my labours over the last 7 months.

It all started with me contacting Robert Nance Dee the designer of my previous build consisting of his PI and Willow I.
He mentioned he had been working on a new design for a preamp the Willow II and it was due to be published in the February 2016 edition of Audioxpress magazine. He then generously asked if I would like to be a tester for him and have a go at building it! When a great designer asks that you cannot say no.
I had no idea what I was getting into and Robert loving minimalist builds, this was all SMD!
He kindly supplied me the PCB's with a BOM and off I went ordering all the parts I was so excited. I'm going to do a complete build of this preamp later on but just to create interest and show what is possible.

And yes it is Arduino powered!

Hey Everyone, I'm wondering if anyone here has suggestions of great sites that are doing objective and honest reviews about audio equipment? I know about the big ones like soundguys and reviews from audiostance. Just wondering what your thoughs and inputs are... Many thanks! 🙂

Help with 2.5/3 way

Hi friends,
After debating about a good quality 2way many people suggested going 2.5way. After research and a lot of thought what makes more sense is to keep my floorstanders, and make them sing.

The floorstanders are made by morel but the original drivers were cheap quality. I tried sb acoustics sb16pfc25 and sb29rdc and even with the morel crossover, which is way wrong since the SB16 drivers are 8 ohm and sb29rdc 4ohms (morel woofer/mid was 6ohm and Tweeter 8ohm) the sound is much better.

The mid driver is at a separate 12 liter sealed box and the bass driver is at a separate 35 liter reflex box
The front baffle measures at 20cmX94cm
The configuration is woofer-mid-tweeter

Here is where I need you guys to step in.

I can do it 2.5way. In that case should I cut holes at the wood that separates woofer and mid in order to unite the volume for both drivers?

Should I keep it 3way adjusting the crossover to the new drivers and keeping the separate volume for mid and woofer?

A friend who has experience, simulated the 2.5way as is(separate volume for each driver) and get these results. What do you think of his design?

Going 3way instead of 2.5way with 6inch midbass drivers, does it makes sense?

Hey everyone,
On 4/14/2014 I purchased a Tubelab SSE board from George.
Well, I've finally gathered every last part I need to to finish this project!

For me, by far the biggest hurdle - so far - was the chassis. My hobby budget doesn't permit a custom fabricated job; I had to go with a $36 Hammond and do all the cutting myself. Using a stepped bit, various files, and sandpaper I ended up with a chassis I'm happy with. I intend to paint it tomorrow with self-etching primer and textured paint (too many imperfections for a smooth, gloss finish).

Here are a couple of photos...

I am going to build a 30watt, PP, 12BH7A/6L6GC amp from the book "Vacuum Tube Amplifier Basics" by EJ Zurich. This design is a mono block, but I'm converting it to stereo. My only concern is the grounding scheme. The author uses many 3 & 5 lug solder terminals, which is fine from a neatness standpoint. However, all grounds, both power and signal, are strictly through the ground lugs on these terminals. There is no starpoint. I've read that ground wires provide a much better return path than the chassis alone. Is this something I should be concerned about?

Hey everyone, I'm a recent graduate from electrical engineering and I want to start working my way into the audio field.

I want to create a passive analog summing mixer with 16 balanced inputs and 2 balanced outputs to use in my personal studio. Basically all mixing and panning is done ITB, summed through this mixer, and then amplified by a mic preamp to make up for the attenuation loss. It's a simple concept and a very easy design for me to take on since this is my first.

I'm not very concerned with the schematic design or functionality, but I have little to no experience creating PCB layouts. Especially in the audio realm where things may be done differently. I was wondering If someone could take a look at this layout and review it and offer suggestions/improvements.

Some general questions I have:
Grounding. I've seen a million different opinions on what to use, and I have ZERO expertise on the subject (star vs plane etc.). Would one of these be better for my specific design? How do I implement it in the most effective way? If I can use ground plane (like I am currently), what area should it cover?
Routing. The dualport dsub killed me. Is it ok to use multiple layers in a design like this? How could I improve my routing? Is 10mil okay for trace width?
Are the placement of my connectors ok? (CAD is not my strength, and I want to be able to use an enclosure properly)

A few things to note:
I want all connectors to be rear facing, so there will be some unavoidable black space (upper right). That's ok with me.
I want to use the dualport dsub connector for the inputs in order to save the most space, even though it makes routing a nightmare.

It honestly blows my mind that I can go through 4 years of electrical engineering and have zero experience working with any kind of PCB design in classes or labs. Thank you for any help, suggestions or ideas, it's been nearly impossible to find this kind of info anywhere.

Hello Guys,

This is my first post and wanted to share this video I made on replacing Belts on the AKAI-747 Reel to Reel I hope someone finds this video useful.. looking forward to future participation in this forum.

If you guys have any questions for me make sure to ask here or on the video comment.. thanks...


https://www.youtube.com/watch?v=WVtDHB4iOjk

I would like to have a relay input selector and an attenuator always with relay that select resistors, all managed by remote control.
Has it already been mentioned?

Hello,

I am hoping to find out about the Pass Labs B4 crossover I have heard about.

Is this available for sale yet? Price?

I am hoping to find out some technical details of this unit if anyone can share about it.

I read about prototypes being in the field a few months back but haven't heard much since.

I was hoping to find out if it offers level adjustment for using different sensitivity drivers/amps.

I also am hoping to find out the crossover points.

Thanks for any help you can provide.

-Nick

This is Colin's Groove Master design: JFET input and ultra-low distortion AD797 op amps. Excellent full-sptectrum noise figure, headroom and RIAA precision. Kit consists of partial kit: 2 manuals (user and assembly), parts list, JFETS and circuit board. I'll include 14 .05% resistors that I bought for 7 important locations (in each channel).
Anyone interested?

Hello Everybody,




today I got a broken Technics SA-5250 Receiver. One Channel was dead. The Power Amplifiers are mounted on Cards, removing one Channel revealed the right channel to be dead. The Drivers and Power Transistors seems to be dead, Collector-Emitter-Short. The Supply Voltage is +-30V.
The Drivers are 2SC1567 and 2SA794. I'd like to substitute them with BD139/BD140, their Vce is lower, but I think 80V is still enough for +-30V.

The Power Transistors are 2SC1667 and 2SA837. For these I don't have a 100% fitting replacement, but I've found two pairs of really old looking 2SD551 and 2SB681, which should be fine, but I'm not quite sure about that. MJ21193/MJ21194 should be fitting too, but I'd have to order these ...




Maybe someone could verify my decision, so that I don't fry more transistors.




Thank you very much


Lukas

What do y'all think of Steven Gunderson's approach?

Note that this is the technique used by Rotel in their RB1090 power amp., and Randy Slone in his designs.

Also available as:

'A Topology to Linearize Miller-Effect Compensated Amplifiers'

JAES Volume 32 Number 6 pp. 430-434; June 1984
An additional topology to Miller-effect compensated amplifiers, which reduces high-frequency distortion, is described. The addition is implementable in discrete or integrated circuits, with little or no additional complexity required in designs incorporating short-circuit protection. This topology is effective in reducing distortion to frequencies greater than 10 MHz. The greatest effect is achieved in power amplifiers with push-pull output stages.
Author: Gunderson, Steven J.

This may belong in the 'Test Equipment' section, but I thought I might share a 3D graph of a 6CA7 transfer curves I measured. There is beauty in it's simplicity!

I put together a concept tube tester based on a RPi and Microchip PIC to make these measurements. (Total cost without the RPi screen and anode transformer is about USD 80). Total measurement time (for 6500 data points) was 40 seconds, excluding tube heating time.

The original purpose of the project was to build a self contained tester that was not tied to a laptop/computer, that was fast, let the tube reach normal operating temperatures (ie not pulsed), but still gave full access to the raw measured data so it can be manipulated with Python script.

Hello , Does anybody have a service manual for this receiver ONKYO TX-8150 or an idea where I might buy one online? Thanks

Hi,

I just wanted to share the results of my first attempt at PCB making.

The board is for a headphone guitar amp and I designed it using EasyEDA. I printed the layout onto tracing paper with a Samsung M2026 laser printer. I made two copies and overlaid them to increase the contrast. I actually had to print several copies to get two that were the same size. It seems that the printer isn't 100% accurate each time.

I used a Bungard pre-sensitised board and exposed it for 6 mins using a MEGA UV exposure unit. I then developed the board in sodium hydroxide for about 30 seconds and then etched in ferric chloride for about 15 minutes. After cleaning off the photo-resist with acetone, I tinned the board in 'seno tin' tinning solution.

I couldn't be happier with how it turned out. I spent a long time reading posts on this forum and in other places to try and avoid making mistakes so I wanted to share my exact method and results in case anyone, like me, is thinking about making PCBs but is worried about how difficult it might be.

I've still got to drill the board, so that's the next challenge, and then see if it actually works! Fingers crossed.







James

Hi all, wishing you all good health at these testing times.

I have an Alpine MRV1507 on the bench, it's pulling excessive current a few seconds after applying remote power.

I've tested the power supply and although it's had a previous repair it powers up and idles fine if I disconnect the 6 pin molex which connects to the output board.

All the output transistors also test good.
Q819 has been replaced with a 2SD600 which had a loose solder pad which I have resoldered.

Initially it would power up then trip my power supply after 8-10 seconds, now it trips within a few seconds.

Any help appreciated, thanks

Further to my poking around inside a Sony XM 6020 I have discovered that the positive rail potential is ~33% lower than the negative rail's potential to ground.

The positive rail measures at around +22 v whereas the negative rail measures at -32 v.

I have noticed that the filter capacitor on the negative rail is also warmer than the capacitor on the positive rail.

The spec given in the service manual is +32/-32 volts.

The voltages at the drains of the mosfets just before the transformer are identical.

The square wave taken from the anodes of the rectifiers seems to be "offset" low, if that makes sense?

Is the problem in the rectifier diodes, it seems unlikely to be the transformer isn't is?

Hi all,

I am thinking to build a pair of bookshelf speakers using Scan-Speak 8" woofers and probably some aluminum dome tweeters from Seas, Vifa, Morell, or any good quality brand. I can build the crossover myself but prefer to buy a kit to assemble it. I have not idea what cutting frequency should I get since I don't know too much about these drivers. For what I have read, these drivers will work cutting them to 2000hz, 2500hz, 3000hz, 3500hz and 4000 hz. (two way crossover)

This is a project I want to do for fun and entertainment but I would like to have good results. I am trying to get advice from those who already has built DIY speakers or know the best way to chose a crossover. I don't know if it could be a good idea to cut the tweeter high and let more mid-frequencies to reach the woofer or to cut lower the tweeter allowing more mid-frequencies going to it. I am toward to allow more mid-range going to the woofer but I may be wrong. I think the woofer handles the mid better than a 1" metallic dome tweeter.

Please, give me some light about how to chose the crossovers and correct me if I am wrong with it.

Thanks

DIYSG Fusion 12's & 8 Center, Yamaha RXV2700, GSG 21" FM boxes, Pr. Dayton 10" subs.

Got some stuff taking up room since my last build.

A pair of DIYSG Fusion 12's with pre-assembled Xovers, plus a Fusion 8 Center. All in black Duratex in excellent shape. Quality binding posts. $500 for the set.

My Yamaha RX-V2700 7.2 AVR. Excellent 1 owner condition. Beast of an amp at 140w/channel. Comes with both remotes, YPAO mic and a suitable box. $200.

A pair of GSG Audio 21" Full Marty flat packs on a pallet. Bought 4, but 2 is more than enough for my room (or my house for that matter). $500 for the pair. Local pickup only (less than half of my total to have them shipped to my loading dock).

I'm open to selling my completed GSG 21" Full Marty boxes filled with the B&C 21" 4 ohm driver finished in Duratex. $1500 firm...local pickup.

A pair of Dayton HF 10" 8 ohm subs in 1 cft sealed boxes finished in Duratex.
Again, excellent condition with binding posts and feet. $old for the pair.

All items built or owned by me since new. Obviously prefer local buyers and would make a great package deal. Would consider shipping but we would have to work out the details Pics available....just let me know. I'm in southwest Missouri and occasionally get to KC, St. Louis, Tulsa so a meet up is always possible. Ebay feedback is Huskerpilk. Sold a few things on AVS forums.

Hello, I have here a massive collection of good film caps. All are new and still have long leads. The vast majority are 0.22uF with the rest being .2uF, .18uF, .16uF and .15uF and only a few being other, close values.
These are all good brands like ITW, Wesco, Acu-Cap(Aerotech), Mullard, Sprague, Epcos, Rel-cap, El Pac, Paktron, G.E., EC, Nytronics, ITT, Hopkins, IMB, TRW, Panasonic and Conrel Dubilier. Some of these like the v161-456 and Rel-caps I only have less than a dozen of each. Others, I have nearly 100 and a few, and like the Epcos stacked caps, the blue ITWs, the Wesco(Northern Telecom) and Sprague orange drops I have hundreds to thousands of.
I don't need all these, especially so many being the same value. I need to get rid of them so no reasonable offer will be turned down.
What I am looking for in trade are some capacitors for a couple gainclones I am working on. I need some good electrolytics that are at least 50v, some 0.1uF polyester caps, and some good input film caps with values of 1.0uF up to about 4.7uF.
I will ship anywhere in the US or even abroad. I prefer trade because it makes things easier not having to deal with paypal but if someone would like to buy a quantity I am open to the possibility. I am fine with shipping mine first and then the other party can ship when when they know their order is on the way.
Here are pics showing one of each type of capacitor I have available. The left side starts at 0.20uF and goes down to 0.15uF. The right side is all 0.22uF. There are also a few pics of the whole collection.
Have questions or want to make me an offer? Please message me or post here. Thanks

Has anyone experienced this issue? I'm about to buy a used UA21292, but....when you put on a cable that is unbalanced, eg. pin 3 grounded, the meters go off.

The manual says that this sort of cable is OK.

Is there an easy fix?

I own an original Lehmann audio black cube linear that has recently started a hum issue.
I know this headphone amp has been cloned many times so am hoping someone familiar could help me troubleshoot.

The symptoms:

When I touch the volume knob I get hum. Both in the headphones and the line out

The hum is louder at high volume and worse when set to high gain settings

When I touch both the volume knob and a grounded part of the chassis such as the RCA connector the hum reduces or goes away.
It does not matter what amps/dacs are connected. The problem is persistent and only if I touch the volume knob.


Where do I start? What could cause this to start occurring after so many years?

Thank you for the assistance.

Hi,

I'm looking to build an enclosure for this old set of Boston Acoustics RC61 I have pulled out of the basement.

Have the two mid base drivers, the tweeters and the crossover.

Does anyone know what the Thiele parameters of this driver is? Cant seem to locate online, and Boston Acoustics responded with my request that "Unfortunately the driver parameters are not available"

Thanks!

Dear all,

I implemented a new Class-D amp which is modulating the PWM signal fully digital with the help of a 4th order noise-shaper.

So actually a similar concept like a lot of silicon vendors out there are using for their digital I2S input Class-D amps.

The full source code is available on my GitHub:
GitHub - YetAnotherElectronicsChannel/FPGA-Class-D-Amplifier

And I also explained everything once again in a YouTube video (including listening tests)
YouTube

Have fun by checking out,
Markus

I have a Krell KAV300CD player, that I really like and I am looking for some cost effective mods to improve it's performance. I have recently had it serviced with a new laser, and I will be re-capping it in the near future. I also heard that an improved clock can make a big difference.

There are many options out there, does anyone have any suggestions? I've been looking at the TentLabs XO, but I have no way to compare the various offerings out there.

Any and all suggestions are welcome!

Hello friends, this is my first post and i really need your help.I have just finish my new speakers with 1 x woofer eminence Delta 120A ,2 x midrange celestion TF0615MR(close back) and 2 x tweeters Beyma T 2030.I have a big problem with the crossovers, can you help me found out what crossover should i use for it ? I use an old crossover from my previous speakers but the result is terrible.I cant use the softwares -i dont understand those-is there someone who can design a crossover for me and what componets should i use? I am given you specs from the drivers :12" Woofer
400 W RMS,8 Ohm,54 Hz - 5 kHz 6'' midrange 97 db, 8 Ohm,50 watt rms,500-5,000Hz Tweeter Power: 15W
Impedance: 8 Ohm
SPL: 95dB / W / m
Extremely high quality high-end tweeter from 2.5 kHz Thanks!!!!!

Full rebuild.

I've already removed all the FETS in the PS section and the Output section.
All dead.
Output driver board for the class D is still in place as I have to fix the PS section first.

I've checked the gate drive in the PS just before the gate resistors (as this ones also have to be replaced).

I don't think this is normal. Two of the banks driving one of the transformers look shifted upwards. The other one looks normal. Pictures attached. So I think i will have to rebuild also the PS board - i think it is the buffer driver transistors.

Dynavox LY302F 3-1/2" Full-Range Driver

Looks good on paper and a Tim Feleppa’s measures look good.....he’s quite smitten with it’s performance. Anybody have first hand experience with it?

Is anyone interested in making a gerber file for me? I'd be happy to pay if it means I don't have to master the software out there.

I've looked at EasyEDA and a few others. I'm sure they are wonderful programs ... if you do PC boards on a regular basis and take the time to master the software.

This a a very simple board, I can send an "old school" drawing with all the components, traces and labeling.

Any recommendations on where to have a small quantity of boards made up? I have talked to JLCPCB. Prices are great but would like to try someone in the states. I also talked to RUSHPCB, they were about 10 times more expensive than JLCPCB. If that's the case with all USA made boards, I'll look abroad.

Lastly, is this the right form for this post? It's software related but I'm giving up on the software and am looking to hire help!


Thanks,

Eric

I have already built 2 TABAQ pairs (MLTL which are very similar in dimensions) and now I am hooked... Now almost any simple bass reflex commercial speakers up to 500EUR with that rubbery bass sound flawed to me.

Your advice is needed for another build. I feel ready for bigger and a bit more expensive, requirements to make it more narrow suggestion:

1. Finished speaker has to go a bit deeper than TABAQ, lets say that 10Hz lower is ok, especially some more bass in 40-50Hz range.
2. Decent quality of treble at 10-14kHz. I really understand, that full-ranger will not be as crisp as dedicated tweeter, but midwoofers acting as full-ranges is not to my liking. I am deaf above 13.5kHz, so the very upper part does not matter.
3. 4-6 inch full-range speaker. 3 inch and smaller excluded. Preferably with as little correction filters or equalization required, but this is not deal-breaker. Price per one driver up to 80 USD/EUR, if there is smth head and shoulder above everything else - can be 100USD/EUR per unit. It should be available in Europe. Probably I am still not ready for MarkAudio, so exclude them for now...
4. Speaker type - MLTL or other similar quarterwave type designs. The sound of them really impressed me, also space is limited. The only exception could be compact front firing horn if it has any advantages to MLTL.

With all above, what you, dear DIY colleagues would suggest me? Is it WIBAQ sized speaker with some cool but cheap driver I want to build?
I am not afraid of Hornresp anymore, so will simulate anything you will suggest me 😉

All suggestions are appreciated! Thanks in advance!

FS are a pair of NOS finished calibrated and tested Jean Hiraga 20 W class A amps. Good way to try out the amp without the hassle of building it and optimizing it. Price $140 for the pair. Two more pairs are available. These were only used during dial in which required mounting them on the heatsink and connecting them.
Modern Toshiba and Sanken (genuine) semiconductors were used. A high precision trimpot was introduced for fine tuning. This is a plug and play board and gives a few mV DC offset on the output. The PCB was redesigned for short signal path and large vias with custom C-channel heatsinks for excellent thermal stability. The +/- supply, ouptut and ground are designed to be screwed on the wire crimped loop terminals. The inputs are solder on.
All that is needed is a CRC-type power supply and a good enclosure with plenty of heatsink. They were setup to match the original Hiraga 20W bias numbers, approx +/-20 V rails and 1A bias. The components are barely breaking a sweat.

input pairs: toshiba 2sa1016/2sc2362
drivers: toshiba 2sc4793/2sa1837
output: sanken 2sc2922/2sa1216

please help me to find out fake or not.Here they are.Thank you all.Hfe is 100

Is this how the power supply squarewave is supposed to look?