Looking for help. I have built the Elekit Tu-8500 preamp. The phono stage is not functioning. The Vcc and Vee which are supposed to measure +and-12 V are measuring .06 V and -3.6 V. And the phono input is not working, I opened it up twice and fixed solder joints. I’m not sure where to go from here. Any help would be be appreciated.

thanks,
Jeff

I wasn't necessarily considering a scope just yet, I don't really know what to use it for, but boy they look fun.
I am sure I will be using it all the time once I have one.
(Although I am keen to measure ripple to start with)

Anyway, I have read a bunch of advice and best value seems to be old analogue scopes.
I like the idea/am happy with learning on an analogue having read much of the advice.
I haven't seen any come up super cheap.

Now, one has come up locally.
Which is handy, as I have had a couple of issues with shipped electronics recently.
It is a Telequipment D83 for £70.

I have never used a scope before and don't know what I am looking at.
I have asked if there are probes.
If not are there reasonable value replacements available?
Could I get an idea of cost of half decent replacement probe please?

https://w140.com/tekwiki/wiki/Telequipment_D83
https://w140.com/tekwiki/images/9/97/Telequipment_d83_oscilloscope_sm.pdf

From searching here, it seems like a few telequipments are being used.
So, that means they are suitable for audio.
50Hz seems good I believe?
It is dual channel which I think I saw was pretty important.

Another working one sold recently for more.
Should I wait for a cheaper one?
Is this a decent one to start me off?

The screen looks quite sharp.
What are the things I should look out for?
I imagine that these older scopes are more repairable anyway?

It has loads of buttons, so it has to be good, right?

Thanks

Hi everyone,

I have a small problem with my Krell, a yellow wire broke off the PCB and I'm still puzzeled about that does that wire actually do?

It comes from the positive speaker connector, has a R8 resistor under a piece of heatshrink, goes through something that looks like a fuse holder and ends on the main PCB.

The question is: Why is it only on one channel? I'm sure that's a factory job as I saw more KSA50's with the same thing.

Does anyone know of any 15 Band Graphic Equalizer that does not use Op Amps ? Though I disagree, my good friend does not like Op Amps, so we need to find him an Equalizer that uses discreet transistors instead of Op Amps.

Design considerations:
1. Will be using a fully active crossover.
2. Relatively high efficiency desired so that I have head room to perform various types of convolution/equalization and not be limited and get the SPL that I want out of them i.e. a little over reference level listening.
3. I desire 'fast' dynamics and transient response to steal an amorphous audiophile term. I've noticed that in my speakers an MTM design usually gives that immediate midbass impact and great transient respond.
4. I have a pair of 0.56 cubic foot parts express cabs laying around that I can leverage. These just happen to have the perfect internal volume per winisd to accommodate the two PA165 midbass drivers in a sealed configuration which is my preference to make sub integration easier.
5. I will be using these with dual subs so low bass is not needed, I just need a lot of impactful midbass down to 100hz to avoid directionality issues.

Initial thoughts:
1. Midbass driver: Dayton PA165: https://www.parts-express.com/Dayton-Audio-PA165-8-6-PA-Driver-Speaker-295-015
2. Tweeter Options

There is a linear selling on ebay which is working fantastic for a application I have, but, its abnormally noisy and a bit unstable. I made a schematic for it and I am confuzed.

Does this look sane ? Its weirdly unstable. Certain loads cause a oscillation. No load has it too. It has a 4mV pk-pk very random looking noise.

Its VERY picky on which mfgr of TL431 and even grade.

I can't find any reference to this layout on-line.

I just got this one yesterday for $200 but couldn't find schematic anywhere. Not sure if it's PP or SE

1. Not sure how to bias and where to check the voltage
2. Is it 6SN7 since I don't see the label
3. Low level consistent humming
4. Loud humming when DAC connect, no problem with SS amp

So far everything is working great with other audio except DAC gives a loud humming when connect
Do you think upgrade the coupling caps would make it better? I have PIO caps around, I think I may try since it's a PCB.

I've searched the threads a few times, but can't find anything particularly recent.

I need (read want) to step up from a series of budget soldering irons to a proper soldering station. I'm a through-hole and p2p amateur. I build, on average, a couple or 3 diy projects a year. I can get Metcal from Mouser and don't mind paying the extra cash for a quality tool. Any suggestions for something from the Metcal range? Even just thoughts about differences between GT, CV and MX ranges would be appreciated.

As always, thanks for your collective or individual wisdom.

Hi All,

Thought it would be cool to see what speakers/headphones people are using with their Elekits and what their experience is? I've got a TU-8600s but also interested in the TU-8900 crews thoughts.

I'll kick off - I'm using Living Voice Avatars (94db) which I a really enjoying but interested in upgrading to horn speakers in the future. Bad photo attached.

Cheers

David

Hello all,

I built both an Elekit TU-8200 and TU-8500 preamp a couple years ago and have been very pleased with them.

Today I played one vinyl and it sounded great. Went to change the vinyl and the next one was much lower volume, had static/distortion in both channels, and the overall dynamic range was squashed (sounds small and thin). It isn't the vinyl, I've tried several and all of them sound like this now.

What could have happened? My first assumption was that a tube died. But I assume that would only affect one channel unless 2 different tubes had the same problem simultaneously (which seems very unlikely). Would a tube (either preamp or power tube) dying cause BOTH channels to be affected? Should I start tube rolling or is it a different problem? I can't imagine what else would have changed so suddenly that it was ok one minute and dead the next.

Thoughts?

Thanks so much in advance for any advice you can offer!

Best,

Josh

One week old. Decided to go with pro grade earthworks microphone instead.Hence selling as partsexpress wont take return.
Looking to get $200

My 16-year old asked me for desktop speakers for his rooms. He's starting to learn about electronics, so a wonderful opportunity to engage with him and build something. He's also into playing guitar and music...so you can appreciate where I'm coming from 😉

I'm thinking a vented passive two-way. He would be about two feet from each speaker.

The 3FE22 would allow me to do without a tweeter (and rolls off above 15kHz...), and couple with a 5 or 6" woofer. He prefers 5" to keep it smaller, and 5FE120 looks good I think. 6FE100 looks better, but it's 6". Would the listening distance be too close for these drivers to integrate well?

These drivers seem good for the passive xo design. I have very limited knowledge on passive crossovers, so easy is good. xo around 700 to 1000Hz, maybe. 1st or 2nd order, maybe?

FWIW, he will be playing music off his laptop into an assemble-yourself class-D low cost amp, so I'm not shooting for award winning audio quality. Yet would like to achieve the best I can at this level of complexity and price range.

Thoughts?

I am buying some PA speakers and I am considering Alto TS312 or Yamaha DBR12. Any pros/cons? The Altos seem to have a lot more power reading the specs...

I have this microphone:
https://www.audio-technica.com/media/wysiwyg/product/pdfs/us/pro35_submit.pdf

It us meant to be connected to an Audio Technica wireless transmitter, and it sounds great.

I would like to use it in another setup, where I connect it to a small (wearable) battery powered amp.

In the documentation (link posted above), it is written this:

The PRO 35cW features a 1.4 m (55") miniature cable terminated with a locking 4-pin connector for use with Audio-Technica UniPak® bodypack transmitters. No power module is included (or required) with the PRO 35cW. The PRO 35cW dimensions, polar pattern and included instrument mount are identical to those of the PRO 35.

I tried to connect it directly to a preamp (who'se output was connected to an amp), and could not hear any sound.

It is not clear from the doc if it's a passive mic, or if it needs to be powered by some kind of a circuit, I'm guessing the later, given that it I can't get any sound from it, and I assume the wireless pack that is meant to be connected to, supplies current to the capsule.

I have also used the mic with this adapter: https://www.audio-technica.com/en-us/at8539
for some reason it died recently, and when I opened it, there was a rather complex cirtuit inside it. The circuit (obviously) is powerd by phantom, and probably supplies the proper current to the capsule. It seems to contradict what the doc says, i.e. " no power module is included or required for the PRO 35cW.

So my question: is there a generic circuit that I can use to interface the PRO35cW to an amp ?

One solution would be to get a new at8539 adapter (or somehow fix the one I have, which is probably beyond my competence), then supply it with 48v, but I'm wondering if there are other solutions.

Can I use a centre tapped 3 wire trafo to create a single rail output.?
I'm thinking 2 X AC to BR, CT to chassis ground.
And then the 2 DC outputs from the BR give me a single rail ...with a floating '0'?.

I want to run an RCF L10-750YK (10" midbass) into a large horn with a throat that will compress it a little less than 5x. I was planning on putting the driver in a sealed enclosure, but when I enter the data from its specs into the enclosure calculator on this site I get .12 cubic feet, which could not even fit the driver in it! If I made it a 10" circle it would be 2.6" deep! Is this because the driver isn't compatible with this kind of application?

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

Hi guys i had an idea for shielding an lm317 circuit im drawing.

When i try to keep the return path as tight as possible i end up with a bus ground, and with most of the vcc vee traces exposed.

I can turn the bus ground into a plane and cover all the exposed traces but i understand such ground enlargement comes with its own set of tradeoffs.

Or, i can make a seperate plane for the same purpose and tie that directly to the chassis+ earth.

This earth layer does include shielding return path for ei transformers and is coupled with ac traces tho. Would all these added noises be detrimental to what im trying to do? Wouldnt it 'bleed' thru the power traces and make their way into the active circuit?

What if i was to use this shield method for the input trace of 317 and not its output?

I finally got around to fixing a friend's Kenwood - I haven't done a power amp project since college (guess how many years ago !). It turned out ok. I'll be glad to supply details if anyone else needs one of these.

Hi everyone. So this came in with a faulty power supply. The capacitors on the power board had blown, throwing dielectric all over the main board, causing some corrosion. I replaced all caps on the power board, and cleaned the dielectric residue off the main board. I also reflowed the components on where I had cleaned up the residue. The upshot is that while the mixer powers on, there is no sound coming through the speakers at all. I am wondering if the capacitors blowing up and spilling their guts all over the main board has killed it off, or is it worth investigating further? What are your thoughts?

Up for sale:

DAC Styleaudio carat-ruby, 80 Eur Keeping

DAC SMSL M200, 170 Eur SOLD

Super Tweeters TAKET-BATPURE (pair), 40 Eur SOLD

Amplifier Dayton DTA-1, Free GONE

Here is my latest video, with a tune. i just added 2 more panels to test what i wanted to test.

It uses 2 Bass panels a side and a d'appolito mid/tweeter combo i once made for somethign else.

The idea is a point source planar. witch i think never has been done. at least i could not find any. the easy way is making a line source or a half line source. in any case never symmetrical 🙁

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Th rest of the building can be find here


Part 1 Frame
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Part 2 Building second frame
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Part 3 Making the foils
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Part 4 stretching the foils
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Part 5 Demo with 3 tunes.
https://youtu.be/tGW1R17ZGNA

Hello,
I bought a Sony PUA-7 (not standalone version) and a SH-165 headshell that I intend to use with my Denon DL-103. while at it, I took a brand new set of silver Litz tonearm wires from another arm I own to replace the (possibly) original PUA-7 wires.

Running the wires along the arm was relatively easy. Now I have two choices: either hook up the wires to the stylus attachment, as in the original layout, or directly to the cartridge (as I saw in more modern arms).

The first choice (original design) is the easiest and most maintenance-friendly, but it's a bit awkward, because the contacts of the stylus side are flat and the wires are soldered to them, while my new wires have nice color-coded round connectors that I don't want to lose. Also, my headshell leads (also silver) are pretty long and the DL-103 is quite bulky, so the wires will bundle up in the tight space and might even touch the record surface. Also, part of the headshell wires is rigid due to the connector solder and sleeve, and the two rigid parts could bump into each other if I have a short overhang.

The other solution (direct cart hook-p) is cleaner design-wise and removes the extra connectors in the headshell and stylus, which may make a difference with a LOMC cart (I will place the step up transformers inside the turntable and connect the tonearm wires directly to them). However this may be a destructive process because I have to remove the plastic parts inside stylus and headshell and I don't know if I can keep them whole. Also there would be some weight loss due to the removal of the plastic part that I may have to make up for.

Does anybody have experience removing the internal connector parts without destroying them? The PS-X60 manual considers them a single part. I tried placing a long machine screw in the center of the stylus attachment and pounding it carefully with a hammer, but it didn't slide off a hair.

Any other suggestions before I risk breaking some critical parts?


Thanks,
gm

I'm messing around with a Rasp. Pi transport and seemingly not getting any signal from the trans to the DAC. Probably a software issue. But, I'd like to be able to check the output without having having to plug it into my system. I could measure voltage with a multimeter or use the scope to see if there is any waveform. I've Googled around, but still have questions: What does a digital output waveform look like? Should there be voltage? (I read it was a square wave, but ???)

Thanks

Login to view embedded media I stumbled over this guy 2 videos .One was 5 months ago totally unrecommending rockna audiobyte stuff for being unreliable then just a few weeks ago reviewing as a standard dac architecture one of the rockna dac:
Login to view embedded media Completely different perspective...what do you know?!
What do you know about this guy's talent of licking a**es?
Login to view embedded media Then the same guy takes on interviewing Nelson Pass while he probably thinks the diy community doesn't really count as we aren't the guys paying 10...40k $ for any amp...Does NP know the behavior of this guy or it doesn't matter anyway cause nobody outside the diy community knows how to compute this cheap talk that changes with time and intere$t$?
Well...if I am going only to COPY an expired 80's patent I bet I can make amplifiers that are better than 99.999999% of ALL the best high end manufacturer's of today for half the price of their lowest of the low entry level amplifier.Will you bet against my cheap talk just because I don't upload a new review bla-bla every 3 days on youtube or do you have actual proof I'm wrong ? I can bet you have no solid proof of that though!

I have redesigned my old SSB01 which had components on both sides. Now I have parts only on one side and added screw holes! I think I can get a nice price for soldered pcb's because used parts are cheap. What do you say, shall I put up a wiki page for checking the interest? Send me a message how to get documentation. Some info here

Is is ok option to make MLTL box around 20 liter with Pluvia 7.2HD in front baffle and CHP-70 on rear baffle? Any experience with mixed full range drivers?
Is it better to go with serial or parallel connection between two driver or depend on amplifier capability?

Clearing house on projects. All boards are as new in the packing I received them in.

SOLDNeurochrome Maida - previous gen R2.12 board with pre populated SMD - £50

SOLD Prasi EL84 Baby Huey pair of mono boards Rev 1.6 - £15

SOLDHi Octane phono pre board V3f - £12

SOLDWHAMMY - £20

Let me know where you are and I'll do a deal on postage ie lower than it costs me

Can anyone help with a replacement meter for a Hickok 605A tube tester ?

Cheers

With the help off Michael.

Hi folks!
Now that we all are wandering about j-fet amps (Zen9) and pre, I would like to see a j-fet version of the balanced line stage (BoSoZ) and I've much appreciated the Krazy project, but has anyone tried to build someting similar to E. Borbely's EB-2000/402?
This is the link to the kit version:

http://www.borbelyaudio.com/eb2000402.asp

and this is the link to the original article (on audio amateurs):

http://www.borbelyaudio.com/adobe/ae599bor.pdf &
http://www.borbelyaudio.com/adobe/ae699bor.pdf

What do you think about?

Customer sent me this amp stating that it would whine and squeal. Most likely due to RCA shield disconnects. Now I'm almost done with this one. I replaced PS caps, R52 and R53 as they were missing. Previously the PS fets were replaced by someone else but that repair seems to be OK. Lots of other misc stuff like RCA shield connections were repaired, a power terminal replaced, Rem tab, etc. Normal RF commonalities. The channels have never been rebuilt.

On the test bench, the amp has a TON of hissing noise through speakers. If I un-plug RCAs the noise goes mostly away but is still present. I tried different RCA Y cables and flipping the 2/4 input switch and there is no difference. If driven harder the noise goes away. Also if I reduce the input voltage to <13v the noise also goes away. Seems the noise is only present when the PS is regulating. I replaced the 1n4003 (D3) diode as I thought it was shorted but I was fooled by having RCAs connected. Engaging the LP crossover eliminates the noise. FP/HP and the noise is present. The board has no damage and all the caps even the tiny ones look and smell OK.

I'm coming up blank as to why this is happening. Any suggestions?

I know this is a long shot but, I am looking for a single Blue Arcturus 71a Tube. If anyone has one or knows where I can find one please reply. Thanks.

Jay

Hello, does anyone know what bias voltage should be adjusted for the vk150 bat stage and how to do it?
I have had problems with a pop-pop noise on the right channel I have changed all the capacitors and it continues to make the noise sometimes it is very difficult for me to locate
I can't check my 6c33s with my test tube either.
Cheers

Are there long live versions of Sanyo's SF-HD850/DVM-34 for StreamUnlimited CD-pro8/Project CD-Box RS2 T/McIntosh MCD-500/Ayon CD-7s/Shanling-S100 ?

This replacement versions are extremely cheap in order of the costs:
https://www.ebay.de/itm/265606415758?hash=item3dd760458e:g:JpcAAOSwPLFiOHOk
https://www.ebay.de/itm/265604093786?hash=item3dd73cd75a:g:cYMAAOSwUnJiNpOQ
maybe counterfeits/fakes and not genuine resp. original SANYO versions.
Consequence is short live time even in very expensive components like mentioned in the header.

Are there electric compatible long live versions available of this SANYO optical DVD pick up ?
Thanks for an advice.

This URL's don't provide the wanted information:
https://www.suos-hifi.com
https://www.diyaudio.com/community/threads/streamunlimited-dedicated-to-high-end-cd.337527/
https://www.audiosciencereview.com/forum/index.php?threads/lets-talk-cd-players.9104/page-6
https://www.diyaudio.com/community/threads/cyrus-cd-xt-se-laser-mech-replacement.357742/
https://www.diyaudio.com/community/threads/cd-player-laser-fault-misdiagnosed-shanling-s100.177501/
https://www.diyaudio.com/community/threads/where-to-buy-pukka-sanyo-sf-hd850-dv34-frame.357283/
https://www.hifiengine.com/manual_library/mcintosh/mcd500.shtml
https://www.akustik-perfekt.de/CD-PlayerSatz.html
http://www.hifi-forum.de/viewthread-158-7021-6.html
https://www.diyaudio.com/community/...m-for-cd-sacd-blu-ray-jmf-audio-bdpm1.387146/

Has anyone ever experimented with this?

I got the idea from the older Cerwin Vega speakers that use a bag filled with SF6 gas. I understand they did that to make the enclosure appear larger and extend the low end cutoff, but I wonder if employing a resonator inside of a sealed box would be able to critically dampen the primary box resonance?

If a properly tuned helmholz resonator can work to attenuate certain resonant frequencies and droning in a car's exhaust system, why couldn't it be used to dampen the sealed box resonance of a speaker?

I show the simplified version to begin with.
I'll be back with the real circuit after some more testings.

I'm playing around with a Nutone 2401b chassis that I picked up cheap. It uses a pair of 6AQ5 per channel. Because it supported having several sets of speakers going simultaneously, I assumed that the OTs would be a little off. But then I measured them ...

They've got a 100:1 turns ratio. 100Vms across the full primary yields 1Vrms on the secondary. That's a 10K:1 impedance ratio.

Obviously I can't use them for this. But what can I use them for? No power tubes I know of want 80k plate to plate. Hell, maybe push-pull 12AX7s?

SOLDPair of MOFO boards with sticker along with a pair of Hammond 193T chokes (Will weigh about 2.5kg total) - £75 and I'll pay half the postage costs will not split

SOLDPair of F4 boards, store power supply board and F4 mosfet kit with 6x IRFP240, 6x IRFP9240 - £75 and I'll pay half the postage costs will not split

I am not responsible for any taxes or fees due

Got one of these a couple of days ago. I also gambled on some new old stock 10000uf BHC capacitors, so a good chance to check them out.

First attempt and I get 'OL' on the display....hhmm...maybe these caps are bad.

Then I realise it is set to a high frequency. Lowering to 100Hz or 120Hz and I get 8600uf....getting somewhere.! I can't remember at which frequency it went 'OL' but I understand that a big old smoothing capacitor is meant for use at lower frequencies. I'm assuming it has 100 and 120 for both 50hz (240) and 60hz 120 mains? So I only need to measure power supply caps at these settings?
What is actually happening to the cap when trying to test at high frequency to give the OL?

Regarding low esr caps such as polymers we may use on digital rails for instance, I guess here it is when we set to the higher frequencies but how would we choose....or does it really matter?

It seems a good but of kit but one which I have some learning!

I am thinking of a DIY home theatre system. Looking for recommendations for a very high performance diy floorstanders. I like to keep pricing under $5k for the floor standers and the lower the better. Would also need some bookshelf speakers for surrounds.

Also planning on diy flat pack subwoofer cab + synthesis hs18s (x4).

Does anyone have these articles ?
I have done various searches but these issues seem to be missing even on the excellent American Radio history site.
I have the later ones but not these two.
Regards,
R.

I remember seeing a discussion of it here but cannot find it. Its basically 4 larger caps connected in such way to mimick the value of a single smaller cap while having much lower distortion. Does anyone have more info on this? Thanks

I was watching an interview for the Belgian TV (VRT) with the great Japanese director and organist Suziki Masaaki, and in his music room i saw a speaker i've never seen before. As speaker nerd i want to know what it is, but i can't find it (which is rare).

Doe anybody has an id what this is:


It's clearly a 2 way system with a horn tweeter and a bigger woofer, but for the rest i have no id...

Source of printscreen is this video: https://www.vrt.be/vrtnu/a-z/wanderlust/2/wanderlust-s2a9/?ndl=true

This amplidier works well but was treated bad by previous owner. Both plexi pieces on top are broken. middle one is fine. Looking for parts

Hi, looking for a little help repairing a Schiit Saga 1.0. In the tube section the right channel has a huge hum and is distorted. Left channel is fine. The amp is fine in passive mode for both channels. Observation looks like the SMD resistor (6SN7 pin 8) - R114 may be blown . It cooked off the digits so I can't read its correct replacement value, I can't just assume its the same as R214 which is connected to the tube pin 5. My R114 is reading 0.5Mohm in situ.

I checked out the two 2.2uF WIMA caps and swapped them. That's not the issue. There aren't many other components to check out in the tube section, maybe a couple transistors? I don't have a scope.

Attached is an image pointing out the resistor in question. If someone could read the label I would be grateful.

Any words of wisdom? I’m not really able to come up with an idea of how to describe that other drivers downstream position and proximity to things on the other side as well.. at the same time the redundant chambers contributing to the upper part of the band with are a red light for me? (Rear and upstream)

this is a good guy and a friend of mine so I don’t wanna be rude but he has no problem with constructive criticism or pointing things out that are not going to work or going to work poorly.

This is one of the strangest things I've seen. Not that it works, but that they got it to work.
A high pressure diesel fuel injector pump running a gasoline car. Interestingly, no one in the comments mentions WWII style aircraft engines.
Have a look at this crazy grafting of a diesel fuel pump onto a 4 cylinder gas engine.

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Comments?

A while back I got a BGW 500D. I nice amp but it developed a problem beyond my current ability to fix in the right channel. Then I found a deal on a 750C and jumped on it. I read a lot (mostly here) on these amps and saw what others did to theirs. I haven't done the cap mod yet but I did add in some bypass caps. Specifically 47uf electrolytics on the PS caps and 0.1uf film & foil caps for C1, C3, C11&12 on the amp modules. I also changed the 1/4" input jacks to RCA jacks, and added a much beefier power cord with a rhodium plated plug. I buttoned everything up, hit the power switch and no "magic smoke" came out so I shut it down and connected a source and a test speaker. I powered it up, the cooling fan spun, but no sound 😕 . After a bunch of trouble shooting, still no sound 😡
Much head scratching ensued. What if... nah, couldn't be. Little voice says "check the test speaker, you'll feel like a doofus later if you don't".
Yup, after an hour or so of chasing my tail, the speaker was the culprit.

Fear not amp fans. The big BGW is now driving a pair of Maggie MG-2.5R's and sounding splendid.

I have completed my first LM3886 project and no mistake I am really pleased with it.

Tonight I decided to listen to and test it against my trusty NAD C320 (recently refurbished on account of the usual start up problem and badly degraded main capacitors). In terms of what I can measure the NAD wins or its a draw. The NAD is quieter, but having said that both are almost completely silent so the measured noise is pretty academic. In terms of what I would expect regarding distortion etc. if I had the right gear to measure it down to the levels these produce, well I expect them to be pretty much the same. In terms of sound? Well that's subjective and my ears are old. Both sound very good to me.

So where does that leave it? NAD C320s and even more up market models can be had off eBay for around £50. Most need some work but it is pretty basic stuff for the most part. I am wondering what the real benefits of the Chip Amp are - it certainly doesn't save money against some of the secondhand bargains that can be had (I also have a Cambridge Audio A3i which has been written about a lot on this forum and is quite frankly superb as well). Here is what I have come up with.

1. The fun of DIY and the possibilities for tweaking and improving and learning
2. Reliability? It does seem that most of those all discrete amps of a certain age are rather prone to failing. I also note that some people do go down a deep rabbit hole of replacing components -- especially electrolytics etc.

What else would anyone add?

Hello,

Just wondering if anybody out there has an ICEpower 1500S they'd be willing to part with. This one: https://icepoweraudio.com/buy/power-supplies/1500s/

Thank you kindly!

Hi guys. New to the site so my apologies If this thread is in the wrong place.

I run a 7 piece party band who will be looking to turn over into the wedding and corporate market very soon. We have always used the venues PA systems at previous gigs (pubs, clubs) but naturally will now need to invest in the bands own PA.

I am starting this from scratch and am completely new to the live music equipment scene. I will be having to buy EVERYTHING mics, stands, cables, lights ect so budget is DEFINITELY a priority.

My question is... I will only be able to afford tops for now with the plan to run a sub/ subs at a later date IF needed at all. Am I better with 12's or 15's. I've seen the LD systems ICOA 12 & 15'S for a great price and they seem to get really good reviews. Those or the Mackie thump 15 around that kinda Price range (I know the budgets low & I'm asking for a lot so please be gentle lol)

The weddings will usually be the standard kinda 100 - 150 people. Would be awesome if I could find something to allow me 200 but I'm guessing this will mean a big financial investment?

For now I am just after something that's passable for wedding and corporate sound quality.

Thanks in advance for the advice.

I want to build an external crossover for my speakers to test different components etc. and not mess with the already existing xo.

what is the best way to run the driver wires out of the cabinet?

im assuming not through the port correct?


thanks !

I didn’t know wether to post this in class D or power supply. It‘s a class D amp, but the question deals with the Power supply lol. I found an amplifier that I’ve been lusting at for a couple of years now. Don’t see them too often, I have one now that runs on US power and the one I found runs on 230v 50Hz. I’m curious if i could swap some components and convert it to 120v. It’s a Yamaha PC9501N.

Looking at the service manual it seems all of the versions of this amp (100V, 120v, 230v) have the same circuit board. it would seem that they actually made a list of the differences between the amplifiers if I’m reading it correctly. The components needing swapped should be available, the four transformers may be the only tricky part. I’m going to call Yamaha parts to see if they can be purchased. Luckily I have a US model to use as a blueprint.

Here is the schematic of the power supply.




Here is a small key in the corner, this is the list I was figuring that had the differences between the amplifiers.



I‘d love thoughts from others. I have no problem doing the work, soldering skills and tools are up to the job, but curious if my thinking will result in a successful amp that runs on 120v 60Hz power.

Thank you,
Dan

I love this kid, he is a genius and doesn't even know it. He simply let Nelson talk, with open ended questions that allowed Nelson to express so much.

If no one got what Nelson is onto with his simple designs, this video explains it better than ANY I have ever seen. Also someone really needs to interview Jill.


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ampslab.com

I've inquired via the website's contact page twice now and it's been more than a week. No response to the email address I provided

Hi all,

When enabling a valid key for my unit in the option section i now get a very nice EEPROM error message.

E2prom : Internal Error.

I already went in the diagnostics menu and backed up all parameters i could find in the eeprom. Did the same with any cal file on the hard drive.

Is there any R&S guru that can shed some light on this?

I already ordered a couple of spare eeproms and i’m heavily debating with myself whether to try and read out the entire eeprom and see what might be wrong. Additionally thinking of putting an empty one in and see what that gives since there is a hint that the serial number and basically everything else can be entered in the eeprom via the diagnostics menu.

Anything i should know, avoid,...

Thanks a lot!

Bart

My AV-705x has developed a bit of a power on "thump" issue. When I turn it on, I here the relays going 'click'.. 'click'' 'click' click ................'cilck'

Its on this last 'click' where the 'thump' occurs.

I am under the impression that the relays should open and close at the same time and if one takes its time in closing, a 'thump' would result.

So what's wrong? Old relays or an external RC circuit which has had some components drift in value?

And does anyone have a schematic or manual you could post?

Thanks!

I am now DSP-tuning a full active 5 way system. And now it sounds top notch. Balanced. Sweet. Powerful, hard AND juicy, controlled and musical! All Front stage.

Well. Do you like flat-flat?

No one does? So why is flat still an issue and just not a very bad old joke, like it IRL is? And this is equally true in all home High End systems?

Pictures 1: 3 way front stage, closed boxes midbass. Not in picture: Twin 6,5 inch subwoofers front, closed box. One 8 inch subwoofer reae, closed box. Picture 2: NOT FLAT =) REW RTA measurement.

Hello, need a bit of help I don't know much about audio stuff. At work we have PA Amplifier MA-181RU and there was always usb in it with music and it worked fine, today we took it out to put new music in and it worked great for couple hours and just stopped. Any idea why it doesn't detect usb anymore (sd card works but sounds so weird), I tried formatting it to FAT32 but no success, also tried with different usb drive, is there anything else I can try? is it possible there is number of songs limit or something or usb reader just died somehow? Thanks

Came across this website a while back, with some interesting projects available.

http://buildaudioamps.com/projects-description/

Hope you guys enjoy it

I plan on building a 2 way without size restraints. My goals are simple. I want to make a LOUD and dynamic two way, which also sounds great. Not just loud. I want to feel the bass pumping in my chest. I want VERY good bass. And here is the main thing ... I need them to be able to be ACTIVELY crossed over as high as 3200, and sound good handing off to a very efficient and good tweeter, which can play very loudly and still sound great. I have endless xover possibilities, via good DSP.
I am open to 8s , 10s , 12s , or even a 15" IF it exists. Pro audio is fine also. I need it to play strong down to 40hz. Nothing lower really needed.
I just figure a large mid woofer would struggle to play well up to a 3200 cover point.
Please feel free to educate the ignorant. And please let me know of any speakers you suggest as well. Thank you very much.

Hi,

I just noticed this speaker which is classified as a mid driver. However the frequency response is pretty much full range. It is down 10db at about 15kHz and a bit more after that but I think it is caused by the rise of impedance rather than mechanical limitations. I can compensate via dsp. I think if coupled with a BR tuned a little lower than the Fs will, the speaker could go to 100+ Hz before transitioning to a subwoofer.

My interest in this is the 99db sensitivity which means this guy can go extremely loud on a 10 W class A amp. The type of loudness you will normally get from the oversized floor stander and multi 100W amplifier at hifi shows.

Any thoughts on this... This speaker is designed to handle over a 100W. So I think 10W will not break a sweat on this guy...

Oon

Good afternoon. Am looking for a older pair of the BK-16 kit with the white FF165 drivers used in them? If tweeters come with them it’s a bonus and if not no worries. Please PM me or e mail me. Thanks Jeff

I have a pair of these (new and unused), they came from Acronman Electronics in Singapore.

SOLD

Selling a pair of B&C DE550TN compression drivers. These are new and listed at a starting price of $200 new, here:

https://www.ebay.com/itm/275346296380

One of my favourite clubs has a VOID 'AIR MOTION' horn system and matching AIRTEN V3 foldbacks and it is simply the best nightclub sound i've heard in Australia, but I thought i'd have a look at their site for inspiration and OMG. the Incubus series is VERY serious kit that also looks incredible. Any of you guys from the UK heard one? Not all their design is to my taste, but I do love that they are being so playful. You guys have any comment? This spec for the INCUBUS Array ... Jebus

Looking for personal opinions. If you were going to be driving a speaker with 4 ohm woofers and 8 ohm mid and tweeters (above 200-800Hz) would you use a 4 ohm OPT or split the difference with a 6 ohm?

Hi, I'm in the process of restoring a pair of Magnat 8P Acrylic and when I took the mid range speaker apart I noticed there is a foam plug inside it which is falling apart as soon as I touch it. I want to replace it but what material is this? Can I use a piece of a dish washing sponge cut to the same dimensions or is this some special rocket science foam? I didnt find any info on the internet watsoever.
Thank you 🙂
Arne

HI, my name is Federico, from Argentina. I have a Krell KSA 100S Amplifier (year 1993). I remplace all capacitors and i find two output transistors broken. Are KRELL 484081 and 484002, do you have the motorola number to remplace.

Thank you

Federico Rodriguez.

I've lost the first post I've done... damn!
It's about a tiny 8x TDA1387 DAC, how we can get the best out if it, if it's even worth it...

In short and less organized (than my lost text):
Under 100USD the cased device, Euro/China mains voltage, caps are from old stocks or worse, not the same in each device... (got one for a friend).
CS8416, S/PDIF to DACs converter?
7 pins header "USBinput", any daughter-board needed as my Mac does not see any device when plugged?
STC seems to be a controller of sources selection, or USB input related?
LT1028 in audio path even if I've only seen some in super-regulators, 5 supplies, +/15 opamps, 5/3.3v CS8416, 5V for the TDA1387s?
Cheap PCB but high potential?

All I've written lost for ever... ok guys, look at that and comment. Don't know how's the sound yet as USB failed on my computer and my VRDS is not ready.

Dear Mr. smartech, hello everybody

I would need for service by a instrument for non-contact thickness measurement of transparent plates the currently manufacturer of the following hologram laser diodes, formerly manufactured by Sharp :

1) LTOH30PA (LT0H30PA), TO-outline
2) GH6C005B3B, outline: "Compact Resin", CD-RW compatible version

by first is a datasheet online,
http://www.daisy-laser.com/products/CD/mechanisms/VAM1202/gh6c005b3_e.pdf
by the second, unfortunately not. For the CDR-compatible former type, inside by Philips CDM9 (CDM-9) there are data sheet online again, (see also patent US5511059), keyword "LTOH12M" by Google, see
http://www.datasheetcatalog.org/datasheet/Sharp/mXqxuqy.pdf

Sharp let me know, that all types of hologram out of production , but unfortunately don't let me know about the new brand. that must have taken over the whole hologram laser diode range. By search on the web I don't find the right informations. Here the quotation of the the reply from Sharp manufacture in Japan to Sharp agency in Hamburg Germany:
===================================================
To begin with the conclusion, we can never support the below models.
Although I am NOT sure whether its discontinuation procedure is certainly implemented,
Production is obsolete and those alternatives are nothing, Sharp is not promoting Hologram laser any longer.
Is “Tiefbassuebertragung” a company spinout from Philips, Thomson or something who used to use these models?
If so, please be careful and investigate the history with them, so that our discontinuation situation will not be big problem (complaint for discontinuation).
=====================================================
But there are nothing advices about new brand.

The above mentioned hologram laser diodes are inside in all
CDM12 (CDM-12) and VAM / VAU 12/22xx versions from daisy laser (formerly Philips), even in the currently available professional versions, as shown in the schematic of the data sheets, e.g. VAM1254 - as you can see by
www.akustik-perfekt.homepage.t-online.de/.../vau1254bis1.pdf - VAU1254/11 Aug 2000
http://www.daisy-laser.com/products/CD/modules/CDPro2/cdpro2.htm (CD-Pro2LF/VAU1254/31LF)
www.daisy-laser.com/products/cd/modules/.../ANVAU12540601.pdf
(Application Note Daisylaser VAU1254-31LF ANVAU12540601)
www.daisy-laser.com/products/CD/modules/CDPro2/cdpro2lfVAMspec11.pdf (VAM1254/21, Nov 2003 page 23)
www.vendoramusements.com/images/DataSheet.pdf (VAM1254/01 August 2000)
www.daisy-laser.com/downloads/products/CD/modules/prem7000.pdf (CD System "Premium 7000" )

Furthermore, this types are inside by Sharp optical pick up HPC1LX ", as the cd player service.manual from Kenwood DPF1030/2030 shows, also as download PDF by http://www.rc5.ru/upload/Kenwood_DPF-1010,2010.pdf

Thank you for your advices about today's name of brand.
Please excuse my not perfect english (I work with language tool by google) but I hope, you can understand the most.

all the best and greetings to California
Andreas Kirschner

We will offer Jupiter Silver coupling Cap....
Made in USA

Hello everyone

for the longest time i've been confused about port (lengths) / tuning.
If you have something like this:


Is the port this:


or does the corner belong to the port like


And how do you calculate oddly shaped ports like this: (where does the port start here?)
Can I just use the port volume in something like winISD and translate it to another shape and it will roughly behave the same way?


Another example would be the L-Acoustic KS21:
What is this port here?

Thanks 🙂

OK so I'm new here an I'm upgrading my amplifier in my car an I've ran into a few questions I'm replacing a Sony XM XMZR1252 800 watt amp with a Orion cb3500.1d I my first question is the amp didn't have a bass knob when I bought it an I checked the only audio shop around me an all they would tell me is call orion an I've tried to an can't reach anyone it's a 3.5 mm audio jack looking input an I was wondering what kind of gain control bass knob would work with it I was told only certain ones would others may harm the amp. Secondly what size wiring harness should I get for this amp the Sony was a 4 Awg an I know that's to small for my orion ishould run 0 awg with this new amp correct? Any help would be appreciated thanks!!!

Title sort of says it all.

What's the general consensus on loose polyester stuffing in vented boxes, for a Markaudio CHR-120 driver ?

I've built an enclosure identical in volume to this 56 liters box :
https://www.kjfaudio.com/wp-content/uploads/2020/04/CHR120-classic-vented-box-standmount-large.pdf

Yay or nay for Polyfill?

Thank you all.

Hi all, very new here!
I get a a high pitched squeal and the display hops between 8 and 12 size on the display for a few seconds then puts up ERROR on the Top RH part of the display.
Is this a transport or laser issue?
Everything spins up ok.

For years I found that even though I wanted to listen to music in settings where headphones were the only viable format, I just couldn't tolerate my meager setup for longer than a half-hour at best. Decades old Sony MDR-V600 headphones driven by an old HeadRoom Total Airhead amp, plugged into the 1/8" output of my Samsung Galaxy S7 phone. But as time went by and I learned more and more online about the wonderful world of analog audio, I became aware of two major flaws in my setup. One I was fortunate to realize by happenstance: because the ear pads had broken down so much over the years that it got to be so bad that the headphones started to hurt my ears by way of the inner planar surface smashing my earlobes down, I was driven to order replacement ear pads (I had to cut the old ones off and glue these on). Turns out that the broken down pads had altered the sonic performance in a very negative way that I hadn't realized.

The other flaw was one that is probably obvious to most readers here: using the phone's DAC. I knew too little to know that this could be a shortcoming. I was fortunate enough to discover Schiit Audio and find my way to the Modi Multibit DAC (NOT the Modi 3, rather this is the almost 3-times-as-expensive mulit-bit version, and I will never ever listen to a Delta-Sigma DAC again after falling in love with mult-bit decoding). I'm now playing Spotify on my laptop through the DAC (still using the old HeadRoom amp) playing 320 kbps Ogg format (Ogg is Spotify's native format, one that I HIGHLY approve of despite its poor online reputation for no other reason than that it's not a "modern" codec). I now can listen to headphones and actually enjoy it, which leads me to my primary reason for starting this thread.

So in the meantime I have tried two different models of headphones to compare to the very old and discontinued Sony MDR-V600. These are the MDR-7509 (not HD, but I don't know what the "HD" version actually adds, if anything) and the Beyerdynamic DT770M80. Both come nowhere close to the V600, which is why I sought out and purchased yet another (used) pair of V600's on Ebay which I was very fortunate to find in decent condition, almost like-new when compared to my very used old pair.

The 7509's have way too much low bass and more disturbingly are very hollowed-out in the low mids, and the latter shortcoming is not one that I can tolerate, as low mids are the principal reason why I bother listening to music in the first place (add crisp highs above 10k and I'm that just much closer to heaven itself). The Beyer's had very nice sounding highs but the middle of the mids sounded like they were being transferred through amplified empty soup cans (in other words emphasized and not in a good way).

So I'll stick with my V600's which I adore, but I wonder why they have such a poor reputation online? I thought about trying the 7506's but after reading quite a few reviews I was discouraged by their apparent shortcoming in bass and low-mids.

Here is one comment on the V600's that I did find in this forum, albeit from almost 10 years ago (in an old thread entitled "Reference headphones"):

Adrculda said:

Fair Enough...
I have both a MDR7505 and MD-V600. Both sound decent, but myself prefer the 7505s as with increased pressure they block out external noise a lot better.
My wife on the other hand has been using the V600 for a while ( about 3 years now ) and she wont part with them.

But... if your good at seeking out deals you can find them around $400 for the HD 650's 😉

Click to expand...

Now in the interest of being totally transparent, I will confess to a bit of an EQ preference I have applied to the V600's using Equalizer APO's 16-band linear: -3 dB on 63 Hz and -2 dB on 10 kHz. Very modest compared to what I would end up having to do to try to make other phones listenable.

Hey guys
I've acquired a diy push pull tube amp based on ecc83s and 6l6gc. Was initially made to take in balanced signal, shorted it to be able to use unbalanced. Been studying it for a while as I do not come from the electronic engineering background.

I want to build some sort of a volume control for this amp.
One of the options is to go with a passive pre amp but for that I need to understand how to match the impedance in order no to mess up with the high frequencies.

There is one interesting design feature of this amp that it does not have a grid leak resistor on the gain stage, just a grid stopper. Now naturally the input impedance is approximated by the grid leak value, but how do you calculate it when there is no grid leak resistor?

I am afraid that without having a grid leak, anything I will put on the grid will add up to grid stopper resistance, right? Does this mean that passive pre-amp is not a viable option and I should build a buffered one? Or does that mean that only a small value pot would work right, such as 10k

I've attached the gain stage circuit for clarity. Please let me know if there are any issues with the drawing. This was the very first circuit I've drawn in my life.

Hi all. My brother in law tell me that he wants sell his loved Elekit TU-8200R with Lundahl OPT and Takman resistors installed.
He owned too one pair of wonderful SAL08C08 drivers in perfect state only connected to this wonderful amp. We would sell all together.
He accept offers.
Best