My Logitech Z-2300 unit suffers from an audible low frequency humming. My observations about the humming are as follows:

• The humming comes from both satellite speakers and the woofer speaker. Though I'd say the humming from the satellite speakers is slightly louder.
• The humming is independent from the volume setting on the control remote
• The humming is present with and without an audio source connected to the 3.5mm input
• When disconnecting the satellite speakers and the woofer speaker, the humming is no longer audible. Though I can hear a similar humming (same pitch) originating from the toroidal power transformer, but it is much less audible.
• The humming remains audible when only the woofer is connected (with satellite speakers not connected) and when only the satellites are connected (with woofer speaker not connected).
• The humming was also present in my previous home.

Upon researching this issue on google, the most probable culprit would seem to be a ground loop. Note that the unit does not have a ground terminal (it uses a two terminal plug). I've disconnected all other appliances in the room and connected the speaker set directly to the wall socket, but the humming still persisted. Nevertheless I have been unable to exclude a ground loop as the cause of the humming. Can a ground loop be a problem considering the device is not grounded to the mains? Perhaps the issue lies with the grounding inside the unit? Would this manifest itself as a humming tone?

Upon googling further, I found a common problem in the Z-2300 is a subpar mechanical joint of two ground wires. See Logitech Z-2300 subwoofer hum solved! | YourITronics. I replaced the mechanical joint with a soldered joint, but unfortunately this did not mitigate the humming.

I then spend some time measuring the power supply circuit of the Z-2300 with my DMM but I couldn't find anything suspicious: mains voltage appeared over the primary coil, the secondary was at 40.2V AC and I measured 54.2V DC after the bridge rectifier. Measuring the rails for the MOSFETs, my DMM reported an initially high ripple on the DC voltage but after a while the reading would stabilize to less than 1V (note this was with no outputs connected).

I then proceeded to try and de-solder the output caps on the bridge rectifier (in order to measure their capacitance, I don't own a ESR meter) but have been unable to desolder them due to all the epoxy on the PCB. As the two big caps still look in good condition in the pictures linked below, I'm doubting whether they are causing the humming.

The similarly between the humming from the transformer and from the speakers leads me to believe the transformer might be the culprit? While reading on transformer humming, I typically read about mechanical humming. In this case the humming from the transformer sounds more electrical though. Is there anything I can try to determine whether the transformer is the culprit? Unfortunately I don't have access to a bench power supply, I only have a DMM (though it can read capacitance and conductance).

Finally, can anyone suggest any further steps for troubleshooting the issue?

Link to imgur album.


edit: replaced images with link to imgur.

Looks like this is a "rare" amplifier? Not much information out there on it. I have been running it as my 3rd spare LOL.



Started doing a weird thing where there would sometimes be no audio, but if I turned the volume way up it would start to play for a while, then stop. Figured I'd open it up and see what's going on.


One of the MOSFET's (looks like the power supply section) let out the magic smoke. 2 more have bad solder joints. Seems simple enough, but I am not sure what is the correct part.



Silk screen on the board says T3055, Part itself is BUZ71A. T3055 is kind of generic, lots of parts come up. BUZ71A has some more specific results, but seems to be obsolete. Found one site that had STP16NF06 as an x-ref.



I understand it is risky buying parts on Ebay, but what about Amazon?? Or, best to stick with the reliable part houses (Mouser, Newark, etc.)



Looking for someone smarter than me with experience to suggest the best route for replacement part?



Thanks!

2 bags for sale or swap. VZ serie 50V

looking for LMT 30734060GAA and LMT 30734050GAA relay datasheets.

thanks

Hello,

Sadly, but I am selling my Paravicini The Head TX-4 MC step-up transformer. It is in very nice condition, with very small signs of usage, but considering it's age I would consider it perfect. I've been using it for many years with great pleasure and I hope it will get into good hands.

It's a legendary SUT with magnificent sound. According to my best knowledge only 200 units were made, this is No.28. They show up for sale very rarely so now it is your opportunity to get one.

Item is located in Budapest (Hungary) and I am happy to ship it globally. I will pack it very carefully.

Asking price: EUR 2.290 plus shipping

If you are interested, please send me a PM.

For sale is my Lyra Clavis D.C. cartridge rebuilt by ANA Mighty Sound in 2018. Since then it has been played only a few hours and it has been sitting in my drawer.
ANA Mighty Sound just recently checked it and they found everything perfect. Cartridge looks and plays as new.

Rebuild includes:
- silver coils
- Ogura PA stylus on boron cantilever
- new silicone damper

VTF: 18 mN
Coil impedance: 6,1 ohm
Tracking: 100 micron / 315Hz

As you can see it tracks better than when it was brand new.

Don't underrate this cartridge, with the rebuild its quality has been raised significantly, with the silver coils inow t plays in a much higher league.
Amazing 100 micron tracking ensures not to miss a note from the record.

Asking price: €790 including express international shipping.
I am also open to serious offers.

Photo shows actual item. You can buy with confidence, I am long time member on DIYAudio.

For sale is my Audio Tekne MC-6310 low impedance MC pickup. It has been rebuilt by Ana Mighty Sound and it sounds very lovely.

Rebuild includes:
- new coils made from silver wire
- new cantilever with Line Contact stylus
- new damper (silicone based)
- cleaning, alignment, testing, fine tuning

VTF: 20 mN
Tracking ability: 80 micron / 315Hz
Coil impedance: 3,4 ohm

Stereophile recommended components under phono cartridge category class A.
New price was around 4200 euros.

Asking price: €1450 including FedEx International Priority shipping.
I am also open to serious offers.

I have the photos of the rebuild and I am happy to share some with potential buyers.

will not use germanium transistors, so if they can make someone happy 🙂

• ASZ17
• ASZ18
• ASY80
• 2N526

for sale or swap

Hello,

I've got a pair of small fullarange satellites in a 2.1 system with some serious phase sifting in the low-mid treble region. The sats consist of the PS95 driver in a 2.8 liter box with a 14cm baffle without any passive filters, and a 8's sub for everything lower than 100hz. Take a look at the REW measurement ( dont mid the high bass output this is just how i like to hear my computer speakers with some extra bass) i am curious about the multiple phase shifts in the 1k-5k region. I dont notice something significant by ear, but maybe that's because i havent listened to a lot of speakers. The mesurment is taken form my ear high right in the middle of the speakers (which are about 1 meter apart and have a slight tilt inwards. Is this significant? what might be causing this?

Here is an idea of a tricolumn speaker using the f88 (or other small speaker). I've designing it using the specs from the paper "Now,a tricolumn- build this efficiente column spekear" by R. N.Baldock. Two questions:

1. How to model it with Hornresp? Simply use parabolic sections? There are some discontinuities in the interfaces between the 3 cylinders (one of them is not a cylinder)...

2. Or just go for it with a thumbnail calculation based on the resonance frequency (L=c/(4*f)) and taper ratio of 1/3, height of the inner tube d=2*L/3 (part 2 of the paper)?

Thanks.

Hello!
I recently acquired a Cyrus iii amplifier for cheap and was wondering if it's worth more than parts. I would really like to fix it but I'm not quite sure where's the problem. When I turn it on with the power switch in the back, amplifier displays different combination of leds (see attached pictures) almost every time and the front panel buttons or volume control aren't responsive. Power indicator shows green or both green and red at the same time. I guess that there is a communication problem between the chips in the front board (the one with the buttons). Can anyone confirm my suspicion? I've soldered and desoldered surface mount components before (no destroyed pcbs so far), so I'm willing to give it a try to repair the board.

Hi. I put a voltmeter across my tweeter and it read a fraction of a volt.

Why is it that people use 250v and 600v capacitors in the high pass filter when the actual voltage reading is so low. Why not just use a cap rated at a few volts and save money rather than paying extra for a 600volt cap when there is no need for it..

I have been using an Ipad for too many years and its time for a new one. I use it almost exclusively for internet use. Getting tired of rotten apples behaviour. Never tried anything else. What other brands are a good alternative? Pros and cons? Thanks for the help.

This is amp number 2

This one doesn’t power up

Here is what I get on the 3525

Pin 1:0.00
Pin 2:5.01
Pin 3:0.00
Pin 4:0.14
Pin 5:2.09
Pin 6:3.60
Pin 7:2.07
Pin 8:0.29
Pin 9:5.47
Pin 10:0.00
Pin 11:0.00
Pin 12:0.00
Pin 13:13.47
Pin 14:0:00
Pin 15:13.47
Pin 16:5.01

Finally: The Art of Electronics | Electronics for physicists | Cambridge University Press

Hi dear DIY colleagues!

I bought me a great vintage denon poa 2400 power amp and pra-1500 preamp.
Sounds nice but when i change the preamp by a newer denon that I still have (pma1055). Well, then i prefer the sound of the latter.
When listening to the pra1500 I experience listening fatigue and it’s like I’m really missing dynamics and the highs are really overly bright...

I didnt’t notice anything physically wrong with capacitors. So I bought me a cheap capacitor tester and started disassembling some capacitors (randomly). I measured the two biggest capacitors (right after the transformer), then some in the tonal circuit. But they all measure fine.

I could measure all, but first I would appreciate some feedback from you people.

Do older capacitors affect dynamics and tones?

Even if they measure fine, should i replace them? Consider their age: + 30 yrs old.

Could i be measuring wrong?

Maybe its just the sound of the preamp? Find this hard to believe though, cause the preamp Im using now is really low end. But sounds better.

One more thing: the transformer does have a hum. But still outputs a nice 23,6 volt.

Thanks for your thoughts on this one!

Ps: i attached the manual (part of) of the pra 1500

Gr

Willem

One thing I’ve never really looked into before and a topic I’m having a very hard time finding information about:

Are drivers that require smaller enclosures inherently better than ones that require larger enclosures? Vice versa? What is one sacrificing over the other?

Hello: I just acquired these drivers; any body have any info about them?
I was told they were used in a factory passive sub about mid 1990's vintage.
The person I got them from gave me no specs except for a piece of paper stating
cabinet volume of 4 cu ft. & a crude diagram of the port & it's internal distance
from the cabinet. No info as to where to put port front or back.
I'm going to try to attach some pictures.

...................... thanks

.................. Fred petersen

Hi
I am selling nr. 3 tubes 845 RCA nos, never powerd on.
All checks before shipping.
Send message if interested

Walter

It could not swing the voltage into a set of lousy Koss 250 ohm cans to play percussion at a good level. Trying to do the same with a Zhaolu DAC's headphone amp literally smoked the Zhaolu's amp section.

It distorts like hell and assume transistors - not the sub-minature tubes, are cooked.

Don't know the shipping - have to find a box - would guess under $10 first class in the US

$25 sans shipping.

If restored to proper working condition, I would not recommend use with high Z cans.

Schiit would not provide a schematic so one is on their own.

The power supply will not fit a "small" Priority box. The DAC and PS
of course would fit the "medium" Priority box but that's around $15.80.

The idea came from xrk971’s 10F/RS225 FAST thread.

I was looking at woofers I could get around here since the Daytons are not available locally, and shipping here is prohibitive.

A distributor with good pricing recently showed up for SBAcoustics, and it got me excited that I may find a suitable woofer, as I already had the Visaton B80 laying around.

Going through the SBA website is no joke! There are so many products, it’s easy to get confused.
I was going nuts trying to find a match to the RS225, then I stumbled onto their new 5x8” race track woofer.

It looked ok to try and I shared the idea on the 10F thread.

That’s when BYRTT pointed out that c-to-c using the 5x8 woofers and a small full range driver would be very interesting, and how about a MTM, or in this case WFW?

The data that BYRTT shared pushed me in that direction easily. Having played with XSim and the manufacturer’s curves, I thought it had great potential.

So, I contacted the distributor, and 2 days later, all 6 drivers showed at my door, COD for only $6 shipping cost! That’s service!

BTW, as a plug, this is the distributor in Taiwan, should anyone be interested. They are very nice, and they speak, or write, Chinese as well as English.

thlaudio web site pages

So, this will be a thread on how it will turn out in the end.
I have an idea, but I may change a few things along the way according to measurements, I’m not inflexible.

Shall we start?

So, as we already know, the woofers will be the 5”X 8” SB15SFCR39-8. Two of them per enclosures.
The enclosures will be sealed.

Inside, sandwiched between the 5x8s will be a 2½" SB65WBAC25-4. It will have a sealed space inside the enclosures. This driver has been reviewed as having a great dispersion and great high end reach… close to a tweeter.

These are BYRTT’s measurements of this driver, in FR and dispersion… pretty good!





MTM, or in they case WFW, improves the vertical polars, as more data shared by BYRTT showed here



After I build them an enclosure, I’ll first try a simple 1st order XO, but will probably settled on a more elaborate one later on…





I’m sure I forgot something, but this is the beginning, so, I’ll keep adding up.

European seller ideally as I'm based in UK.

nice - very little use since serviced by Monarchy. Ran it on my Klipschorns. DC offset: 0 volts left, 2 millivolt right.

$445 not including shipping (probably $70 or more UPS from WV to CA)

- could not locate its original box but will have sufficient XPS foam padding.

US Only. Paypal Only

Hey all,

I will be honest. I have been working with audio for many years, engineering source parameters as an ME, and I am taking a deep dive into building my ideal mastering main speakers.

No need to go into tons of detail in terms of driver specs etc too much. The plan is to use a 10" sub, 6" mid, and planar tweeter.

Many of my favorite designs use an MTM -type format, at least with the tweeter below the mid. Grimm LS1 and Stratus Gold come to mind.

Another thing I've noticed in the best presentations I've heard is having mirrored tweeters on the outside of the speaker. This seems to improve imaging as well, although in a different way than MTM.

I have a terribly inaccurate two-second mockup that shows two concepts for the design. Would love to hear people's opinions about what would perform better.

If anyone is interested in more aspects of the design, I'd be happy to share them. I just figure that I'm verbose enough as it is. haha

I'm looking for a simple 38 - 40v 150ma P/S built around an LM7824.

I thought a 15v Zener on the centre pin with an 8k2 from the o/p pin, to make sure the reg. is not starved, should jack it up to 39 volts as I have all the parts lying around.

But, the LM7824 is rated for a max i/p of 40v. - Am I correct in assuming this refers to the max i/p voltage between i/p & centre pin, & as long as it is below 40v here, it should be OK.

The total input voltage I'm feeding to it is about 46 volts which should leave about 31 volts between the i/p & centre pin.

Comments please.

I am not used to this type of layout, why are there 2pairs of mosfets on each rail that is connected in series with inductors?
First pair triggering the second or what?
I feel stupid!
Rail voltage +/- 118v

Yamaha yst sw1500 triggers protection

Recapping this but come across some 470uf 120v caps at positions 513/514 in the power supply and 401/402 between amp modules. Any reason these need to be 120v or will 100v work just as well?

Just wanted to see what people thought of this bloke on YouTube I am following
Was going to give it a try on my Marantz 2238 old receiver and a couple of Sansui amps
Is your Amplifier & Speakers Balanced Correctly, Stereo Channel Tune Up using Audacity, Hifi Vintage - YouTube

Rav.

Hey fellas,

Having recently been made redundant it may be time to downgrade some of my Hifi gear 🙁 First to go will be my DAC. It's a Trichord Pulsar DAC that I bought used a few years ago, although it cost £1400 back in 1994.

My thinking is to replace with a modern budget equivalent (CA DacMagic), which sells for around half the price of the Trichord on the used market (£150 vs £300) - I'll pocket the difference into savings.

Reading up the on the DacMagic's specs it looks as if DACs have come a long way the 15 or so year between them so I was hoping the audible difference will not be that great. Before selling it, curiosity has got the better of me and I've decided to see what is in the Trichord component wise to compare:





To my surprise there are two toroidal transformers housed inside the main DAC, as well as an external PSU!



Compared to the DacMagic, there are obviously far more quality component with regards to capacitors and power supplies, although the circuitry seems far simpler.To be expected, given their respective age gap of 16 years:

ImageShack® - Online Photo and Video Hosting

What do you guys reckon? The DacMagic has had plenty of praise since it's release I am hoping the far more advanced chipset/DAC chips will compensate for it's relatively cheaper output stage and wall-wart power supply...

Since there is a 15 year difference between the designs, this seems feasible to me, or am I dreaming?! Since the £150 saving I will get by "downgrading" is fairly modest, I don't want to do something I regret.

Thanks for any advice

MS just upgraded all four of my PCs (Win 10). Now RightMark analyzer crashes.😡

Purchased a bare bones Fusion 12 kit from DIYSG back in August 2020. Erich was able to provide me with a list of crossover parts but no photo or schematic of the crossover. My last email response from him was in August when he stated that he would provide some sort of assembly instructions for the crossovers. Have emailed several times since then but no response.



Wonder if anyone would be willing to share this information, privately of course. Would like to run this by Erich but I would not be asking for this if I were able to get in contact with him.


Not trying to be a pain, and I know Erich has been busy moving. My guess is he has not been able to come up with this info and is too busy to research it at present.


Any help would be appreciated
Charles Sedivy
csedivy22@gmail .com

Hello. I've recently received some Seas T18 coaxial drivers. I've quickly thrown them into some sealed enclosures I had which provide a qtc of between .5-.6 according to calculations. I am using them close the wall and one is near a corner in a fairly near-field apartment listening setup. With some very rough measurements and based on what I can find online I've dialed in some basic crossover options into my mindsp SHD and measured to ensure they sum to a fairly similar FR. This driver seems to allow for 1st order crossovers, Seas uses 2nd order for their Loki kit, and I noticed their minidsp active preset they provide for the Loki uses 4th order LR with some EQing to flatten FR further. So far they sound pretty good! It's my first time using coaxials and I'm enjoying the 'solidity' to the sound when moving my head. As I don't always sit in the same place on the sofa and often move around the room, I can def notice a more cohesive less phasey sound when not in the sweet spot which I'm enjoying.

What I'm trying to understand is, does using a coaxial fully removing lobbing issues associated with each crossover type? and if so is there any reason a 1st order would be recommended in this instance over a simple 2nd or passive/active 4th? I suppose it depends on if I stay active or go passive, I assume running active there's little reason to not just use steeper filters, and the only reason to not do so passively would be costs/complexity of crossover?

Goodmorning everyone,
I have 2 80's speakers from FBT, it's the Europe l1200
RCF L18p200n woofer + RCF n980 driver
yes, you got it right, a 2-way with 18 woofer
the sound is fantastic, vintage as I like it but the bass is few
the case is about 110 liters with two 150mm holes without tubes
simulating with bassbox I noticed that they aimed at the peak of 80hz sacrificing everything that comes first.
can anyone tell me if i can improve the bass by working only on the reflex ports?

A tube amp was given to me. I powered it up and the 4 rectifier tubes lit up, about 5 of the 12AU7 tubes lit up, and the longer slender tube by the choke flickered / stayed constant/flickered. I think I have a stereo integrated amp. Please see my images attached.

I searched in the vintage Hammond catalogue and came up with the following:

2 x Hammond 1626X OT's, 20 W each. "X" means chassis mount

1 x Hammond 710X T 110VA

1 x Hammond 1136X T 78VA

1 x Hammond 159ZC 06H 2000mA choke

The rectifier tubes are RCA 7027A tubes and the slender flickering tube I am not sure, the label reads 0A? .

Think this might be a project to spruce up modernize a bit. Since I am a novice in this hobby, I am looking for comments and recommendations.

Regards,
Myles

I have always built sealed subs; several reasons, but anyway, I have been looking into BP-4 alignments to reduce the mid base distortion mostly, and because I never did one. Anyway, I have a Dayton RS265 HD and a Dayton Titanic 10. Both good drivers for their size, reasonably low distortion, and work well sealed. Small, but I listen to music not insane loud special effects. They seem to model pretty well, but I do not know what a BP driver should be optimized for. Both have low EBP. Ports come out very long, but do-able. Do I want a low or high Qts for example?

So, wondering if there are suggestions for alternate drivers that are known to work well in BP-4. I need to pass 25 to 80 Hz. The Titanic comes out pretty good at about -3 dB within less than a dB of ripple. Excursion is within reason as long as I toss in a 20 Hz first order HP.

I looked into PRs as I have not dealt with them before. I see some advantages, but would need probably at least a 12, if not a pair of 10's. Costly. 4 inch port is coming out as 9 m/s but 42 inches long. I had a 3 on the Titanic years ago and it was horribly chuffing. I think it calculated at 17. So much for 1/10 Mach theory.

Just curious. They have a known pleasant sound no matter what is being used with them.

Hello 🙂

I have this plan of a diy audio interface. The goals are as follows:

1. USB connection
2. at least 1 instrument input (for guitar)
3. at least 1 output (for headphones)
4. 16bit/48K minimum
5. integrated preamp/headphone amp
6. preferably usb powered, but I might have a 9v transformer that I can use for a linear supply.

Initially I planned on taking a cm108 board and just hooking up an opamp buffer with a level control but while researching on some alternatives to that board because mine had a noise floor of like -60dB, I fell into the DIY audio hole. oops. The analog part should be fine, it's the digital part that I need some help with.

Now, my plan is to take a CM108 and wire in a PCM1802 ADC and PCM5102 DAC via I2S. I chose the combo as I feel like it has some potential to sound good. Is this a bad idea? I don't have much experience with digital audio. I tried researching for other DIY audio interfaces, but I'm a bit lost. I'm open to other options. budget would be approx $30 max.

I'm also looking at modding this, as it apparently sounds good and it also has an I2S input.
SA9023A + ES9018K2M USB portable DAC HIFI fever external amplifier audio card (i'm not buying from this site, only put here for reference)

The reason I'm doing this is because I don't have much money to get other boards or complete units as international shipping is way too expensive in my country (Philippines) and also because I want to get my feet wet in audio more. I'm not really interested in making full speaker setups.

Thank you so much, and apologies if there's something wrong as this is my first post.

Would this be good woofer for 3-way? I would use about 450 Hz crossover. What is 2,83V 1m sensitivity at 100 Hz?

Hello there, I'm trying to build a ported speaker box for 4 inch 16w sub. I don't know how to choose the dimensions. Also I don't have any other specifications of the driver. Can anyone please help?

Hey lads,

Thinking about getting a Bluesound to replace a Parasound combo (CD-1000 + DAC-1000 upgraded to K-grade). Only interested to know how they compare as sound?

I'm building a 3-way speaker based on a Hypex FA253 plate amp with an integrated DSP.
All three elements are flush mounted in the same plane. I use the time delay feature in the DSP to get the timing in synch (due to different "sound pressure distances" and different distances to the listening position).
The crossover filters are standard LR4 filters both between low-mid and mid-high (~390Hz and ~2500Hz).

I have worked a lot with the getting the phases in synch in the crossover section and ended up with a rather large "separation" between the High pass and Low pass frequencies in each separation.
Example: The mid is set at 370Hz and the low is at 409Hz and with this configuration I get "clean" tones close to the crossover section (based on listening to music, not test tones).

Is it normal to get this wide separation of frequencies, or have I missed something important elsewhere?

Another observation is that I hear a difference with single Hz steps (409 is better than 408 or 410).
Is this normal?

Please share your experiences.

I always wondered why different valve types sound so differently in guitar amplifiers - not in the preamp, that I can understand, since the sound is created by multiple distorting stages.

I wonder about the power stage - in modern guitar amplifiers, the output stage is far from clipping and compression, e.g. Mesa Boogie Dual Rectifier or Laney GH100L.

The two amplifiers mentioned above have the option to use either EL34 or 6L6 tubes, use fixed bias and a bias switch and there are many others that have this option as well, I only own these two.

Both amplifiers have a totally different sound with the two tube types. EL34 tone would be best described as midrange heavy and the 6L6 sound would be more like fullrange or even mid-recessed compared to EL34. All this is most apparent with distorted guitar (think heavy metal and more), where the signal is closer to a square than to a sine.

My theory was, that this is due to the phase inverter being optimalized for one type of tube will interact differently with the other tube type and that the distortion profile and frequency response is therefore different for the whole power stage. But there is certainly more to it, I would welcome any ideas on that.

I also have another amplifier, with cathode biased PP EL84 power stage - and it has a pentode/triode mode switch. The triode mode sounds more fuzzy and compressed than the pentode mode, again with distorted guitar sound. I wonder if that is because different frequency response of triode vs pentode or because of the different distortion added - it is again even at low volumes far away from any clipping in the end stage. Ideas welcome here as well🙂

With HiFi and music type signals, I hardly notice any differences between valve types and amplifier topologies - there are some, but not as pronounced as with the guitar amps.

I am hopefully shipping a FHL kit, made for Fostex FF85WK drivers, to Cyprus early next week (just waiting for payment). The buyer is asking me for a recommendation for an amplifier to go with them. I mentioned the Amp Camp kit, but don't know if he is looking for a DIY or commercial product. I also don't know his budget.

So my question, broadly, is how does one choose an amp to go with a particular set of speakers, or drivers. I understand that driver efficiency has a lot to do with it but surely there are other factors, namely budget. Can anyone enlighten me??? Thanks in advance!!

P.S. Yes, Cyprus. The island in the Mediterranean off the coast of Lebanon. Please keep your fingers crossed for me on this one!

Hi everybody,
like almost any audio DIYer, I would like to embark on a new project, so I sell these Seas Excel drivers:
- 4 x E0018-08S Seas Excel W18E001 6,5 inch woofer
- 2 x E0011-06 Seas Excel T25CF002 1 inch tweeter soft dome

They are used (only in home enviroment, non-smoking home) but in perfect conditions and all with the original box.
I would prefer to sell the whole drivers set.
The request is 800 Euro plus shipping.
Please post me you email for photos and any further detail.
Thank you!

Two partly populated modules ,Nichicon caps and Gold Tune PSU caps .
Rectifiers diodes are included but not soldered on the boards .
Modules do come without the lateral fets .
100 Euro + shipping

Burned out my PC speaker salvaged amp on one channel.

😡Crossed wires preceded the event.

I had just finished by mini bookshelf speakers, so I badly need an amp. It occurred to me that the USB powered PC speakers might work off the USB phone chargers that come with every phone these days, so I rushed out and bought a set of these. I think it has a 8002 chip.

Similar to this one Cheap USB Speakers Teardown - YouTube



Anyone tried this chip amp?

Removing the speaker front cover and the screws, I discovered that the amplifier was not inside the speaker but on the small volume control module.

After cutting the speaker wires and stripping the insulation, hooked it up and works very well, just needed a powerful enough phone the HTC one- details later.

Is there a trick to remove the amplifier board, without the PS board ?

All screws have been removed but the board doesn´t move.

I remember that was also possible on other boards.

Hello,
i have this D.Class 5 channel car amplifier, without remote control (subwoofer channel).
i have tried with 50k or 10k trimmers, but don't work.
someone know exactly schematic of this remote control?
in attached pictures of little internal board.
thanks 🙂

They say three house moves equal a house fire. Well, my old Yamaha R-90 endured two moves over the last five years, but finally quit on the third one.
It powers up; all displays light up (tuner, equalizer, source selection indicators etc) and all buttons work. BUT there is no "click" that would follow a few seconds after power up, and there is no sound, not even the slight rustle I'd sometimes get turning the volume knob, not even in the headphones jack.

From the reading I did, I understand the absence of a click is sign of a relay not functioning. I have a multimeter and the service manual with schematics but I don't know how to read schematics, so I don't know where to find this relay.

I live in the boonies, so there is no hifi repair shop near me. I gotta do this myself.
Any help is appreciated.

Here be the service manual with schematics:
hfe_yamaha_r-90_service_en.pdf - Google Drive

Hello!

I've recently finished a heavily modified TDA1541 board and would like to share my results. First, a picture:




Larger Version Here

The summary of modifications is below:

• 192kHz and probably 384kHz capable (more on that later)
• Custom WM8804 adapter to replace CS8412
• Custom FPGA to perform I2S to PCM translation in place of SAA7220
• Custom output stage based on AD797 I/V and AD8599 Sallen-Key Filters
• Selectable taps on output stage to choose level of filtering (I/V only, 2nd order, 5th order)
• Staged DEM capacitors based on current
• 100pF DEM cap with 6.8K pull-downs to -15V (verified 750kHz+ lock)
• Schottky power diodes to reduce noise
• DA101C transformer and proper (fixed) circuit for SPDIF input

The custom WM8804 and FPGA boards have their own local 3.3V regulation. The WM8804 has a high-stability crystal setup and runs in hardware mode outputting 16-bit I2S (32-bit frame).

The output stage is a standard I/V implementation into a Sallen-Key Butterworth arrangement with all poles at 20kHz, verified to not drift across 5% component variation. All capacitors used for this filter are Wima FKP.

The novel part of this circuit compared to others I've seen is the use of an inexpensive (<$3) MachX02 FPGA to do the I2S to PCM conversion. Unlike other conversions, my HDL correctly drops the incoming BCLK frequency by 4x, and doesn't waste any bits. Of course, one channel is 1 sample behind the other to allow parallel operation, but this doesn't mean anything in practice. Live output measured on a logic analyzer can be seen below:



Unlike the discrete logic versions, this one has Latch Enable properly timed between clock pulse edges to allow a 4x reduced clock signal. Basically, it's a direct implementation of the datasheet specifications. 192kHz operation works flawlessly and I assume 384kHz would as well, with 32-bit I2S frames. (32*2*384000=24.576MHz, and 24.576MHz/4 = 6.144MHz, within the clock input specifications of the TDA1541A.)

Is there any interest in the HDL or Gerbers for the FPGA board? I assume most people have their own favorite USB/SPDIF/I2S input device and the arguments about output stages are unending... I'm not even sure this is the final form of the output stage. At least we can all agree on 1's and 0's (I hope). I would really like to know if this opens up 384kHz (DXD) playback.

Oh, it'll also take 24-bit data fine and toss away the useless 8 LSB of noise, but that's done in the WM8804. I haven't tested the FPGA code for 24-bits but I think it will work fine and just ignore the 8 LSB.

Questions, comments, hatemail, etc. all accepted. I'll try to reply when I can.

🙂

Hi, im new in tubes.
Have just assebled a 2x16 watt AMP. Id like to use my stax headphones (electrec type) that are driven with speaker output.

Is that load ok for tube AMP? Or how do i calculate???

Thanks and sorry for the simpel question!!!



Best regards
D. Loncar

I'm looking for a few connectors to slide onto these pins but I don't know what to call them. The pins are 0.72mm or 0.0285 inches wide. I don't need them to be connected side by side although that would be ok.
Thanks in advance.
Dave

It’s easy, it’s cheap, it’s got lots of quarter path shape options and it’s my ‘day job’. except we are a swing shift from 4 pm-3am... and we listen to streamed WiFi or ancient PA overhead in the gigantic multi area open floor plan space and it’s a bit large to use a conventional ‘boombox’, so we might ‘grow’ and it’s a structural steel shop, so it can be built and heavy... forklift and steel is everywhere...

it’s a go if I can get the owner to okay it. she, only needs to see a drawing or anything and it’s most a sure thing as anyone above me is on board and have approved.

no $$ on her end. Only materials to make it are the deal. And with that I suspect it’ll fly. but is the idea stupid, or a waste of ‘novelty’? Steel in a steel shop is the fun factor and why it’s even considered or approved I’m betting.

The fabrication complexities are a welcome addition and even exposing any is fun as nobody really does’ speakers ’ Diy, but some musicians and Music hobbyists are coworkers..

Plain Jane TL with offset driver and single or pair of 12, 15” Dayton ultimax, RSS or DSC or similar are easy to convince people are okay to invest in. Anyone, just give them the link to parts Express and it seems to be fine and I don’t have to pick and choose why Wal-Mart drivers and Amps or car audio crazy boom Boom from Best Buy Might not be right for ‘everyone’ to listen to all night... and there’s all the car audio ideas in power and amplifier the midrange and tweeters and everything in this already... if it’s a ‘go’. it’s a collection of parts and pieces if it pans out as everyone chips in ‘stuff’..

however, that is not in question to you guys.. I will certainly listen to speaker people and suggestions🙂. Hecxecrge question if it’s validity?

Most likely , 10-14 gage pressbroke and thus rigid with internal bracing and minimal volume losses and CSA in the path of a TL? Then, shot with a deadening ruberizrd compound like under coating for chassis? mayvevlined with pink Home Depot foam insulating boards, I don’t think I can use concrete brisk, lol. or id ask... and while I can use plywood in areas I really need to sell it by ‘steel’ to the owner or it’s Back to the boom box on overhead PA system 25 feet high thru the phone line to ... junk!And cannot hear much of it over the noise of production. It’s no good...it’s 45 years or older to and part of an old drive in theatre with part of some other stuff including back to 1954 when this shop started by ‘to the owners father.

Mild steel is possible? Weight doesn’t mater, nothing does, technically, except that I can create a proper ‘steel’ TL...?

Hi, a quick idea that I would like another fellow DIYer to give some advice. The Sledge amp in my 8 year old SVS SB-12 NSD have stopped amplify the signal (IMG STA-400 is the model I believe, hard to come by any spec sheet so impossible to know what I'll be paying for) so in instead of getting an exact, old design and obviously not very reliable replacement for ~$300 I have the idea of doing some modifications to the existing steel plate and putting a ~$400 (I'm in the EU) miniDSP PWR-ICE 125 (Plate Amplifiers : PWR-ICE125) in there.

Would you say the 1x450W (hmm, datasheet seems more like 170W at 1% THD..) be able to handle the job? I measured the 12" woofer to 3ohms if that helps.

https://icepower.dk/download/1636/

Here I offer for sale complete FIFO kit, which I purchased in Ian's Group Buy VI.


Kit includes: FIFO board, dual XO clock board, Isolator board, I2S to PCM board, SPDIF board and various cables.

I played around with the kit a bit but unfortunately never put it into DAC.

I will ship within Europe.


Asking price: 260 euro.

I'd like to modify the loudness circuit of my amp to work like another amp. After reading the schematics, fortunately, I found these two amps have the same loudness circuit! It is posted on attached.

The specs of my amp:
+8dB @ 100Hz
+6dB @ 10kHz
Component values:
C1 = 180 pF
R1 = 47 kOhms
C2 = 0.027 uF
R2 = 18 kOhms
VR = 100 kOhms

The specs of the other amp:
+15dB @ 50Hz
+5dB @ 10kHz
Component values:
C1 = 1500 pF
R1 = 8.2 kOhms
C2 = 0.47 uF
R2 = 1 kOhms
VR = 30 kOhms

Can I change the values of the loudness circuit of my amp (C1, R1, C2, R2) to the same as those of the other amp?

Hi all,
Does anyone have any information about the 10-pin socket from Telefunken (type "30216") which the EL152 uses?

https://frank.pocnet.net/sheets/128/e/EL152.pdf

Searching the web there seems to be some sockets refered as B10B 10-pin which are sold to be used for this:

Wholesale Buy Various Tube Guitar Amp DIY Repair Parts from mafaudio Vintage HIFI DIY

Looking after the drawing and dimensions to manufacture some good PTFE ones
Thanks
Ale

I find I usually spend about 1/2 as much on a receiver as I do on my front channel speakers. Is this about right>??? What kind of Receiver/amp are you guys running for said speakers?

I am currently looking at both the Parts express Solstice kit, or just buying the Philharmonics BMR Philharmonitor. With this said, my receiver is an old Marantz SR585. Will this suffice?

Hello guys,

I am new here and seeking some help. The first problem i have is my wife 🙂. she made me sell my klipsch rf-7. because she wanted a big wall closed for the tv. so i start making my own speakers.

For music all my speaker design sound really nice. very big open sound. but the problem is that with movies the dialogue is not good. i need to turn up the sound very hard. but i need to put it so loud that when there is a action scene the windows blow out of the room.

i kept swapping drivers and horns. until i bought electrovoice zlx12p. And with these speakers i don't have that problem. So now i know it is a speaker design flaw. i i want to get it right

I have measuring equipment

My current setup
active crossover xilica xp-4080
stereolab traxtrix horn with b&c de400tn
celestion tf 1525 15 inch woofer


Please help.

I am trying to clean up some space on my driver shelf, so will be posting some. drivers for sale.

1. One pair of Satori TW29RN-B mounted and measured in couple of prototype baffles. One of the lowest THD soft tweeters out there. Price: $210+ US shipping and PP fees

2. Two pairs of SB17NAC-8. Basically lowest THD drivers out there, you know the rest 🙂... Same story mounted and used for some prototyping. One driver is from earlier batch and has smaller dust cup. You can see from the impedance sweep I just did they are all within production tolerance (don't have freq responses handy, but they were "identical" as well). Price: $45 each + US shipping + PP fees

Will see what also I have and might add some drivers. Thanks for looking.

Anyone have any suggestions for an affordable Differential Scope probe or adapter box? Looking for something that can handle not only audio bandwidth but up to 100mhz preferable and 1mv to 100vrms input.

Like the subject says I'm looking for a good tutorial on how to design something simple like this Two Stage Direct Coupled BJT Amplifier Circuit


For example how do you arrive at the bias voltage for Q1? The divider sets the bias voltage but what parameter in the datasheet would give you a clue? Thanks.

Hi guys,

I wanted to ask you, if you can recommend me a 8" driver with 4 ohms which can be used for ported subwoofer applications. Target tuning range would be around 35-40 Hz.
A high sensitivity would be great.

For me this is just a fun project, so I would not like to spend more than max. 40$ or so per driver.

Can you recommend me something in this direction?

Maybe fyi: Please ask not why, but the target would be to build up a PA-like subwoofer. But want to use an array of 8" for this. Probably 8pcs or 10pcs per enclosure to reach similar SPL like a double-15" or double-18"

Looking for good physical condition and 100%operational. Let me know what you have. Thx Peter

Our system in the church is roughly 25 years old and is going to be replaced by a modern system. One question we have is about the current speakers.
There are 6 main speakers in the church and a total of 25 speakers across the building. They are all 100v and connected to 4 (parallel connected) cables leaving the power amplifier (the current amplifier has 1 connection).

In the new situation we want to fine tune volume per speaker, delay and maybe other characteristics(?).

Assuming we replace all the hardware but not the speakers. Can we achieve that requirements with the current cables and speakers?

I bought a good few boards from Marks group buy but alas I shall not get to build them all. So up for grabs are 4 amp boards and 4 psu boards.

£20 delivered within Europe. Anywhere else please ask.

Any one tries them and can give a review?

I was rereading Morgan Jones' book (hoping that some more would sink in) and I came across a section on feedback. Just want to make sure I've got the basic ideas right...

Cathode feedback is best used from dedicated taps built into the transformer. These are different from an "Ultralinear" connection in that you can use whatever voltage you want instead of applying the entire B+, right?

If you don't have the dedicated taps on the transformer, you can achieve a type of cathode feedback from one of the secondary taps. Do you have to have an unused tap (i.e. an extra 8 ohm tap when you have the speakers hooked to the 4 ohm) or can you source feedback from the same tap you have hooked to the speakers?

Jones mentioned in passing what he thought should be the optimal configuration, feedback from the speaker terminals. This makes the most sense to me too but I must be missing something since I have never heard of anyone actually using this technique. What would be involved in using feedback from the speakers around the output stage of an amp? I suppose taking feedback from the speakers and applying it to the input would be the very definition of a global feedback chain🙂 I tend to shy away from global feedback because of stability issues, I assume that it would be even more tricky if the feedback was sourced from the very end of the chain, am I right?

Thanks for any info you can send my way, still scratching my head over how some of these things work, I'm hoping to start on my first amp before too long...

Isaac

The OPA541 is a powerful chip.
Package is 11-pin TO-220.
When used with only a few parts it can output 9-10A and dissipate 125 Watt.
Power supply can be up to +/- 40 Volt.
The THD is low but not the best.

To perform with lower THD we can use a driver chip.
This will control the OPA541.
We need an op amp with max power supply +/- 40 Volt.
This is where OPA452 comes in.
Package is 7-pin TO-220 or DDPAK/TO-263.
OPA452 is unity gain stable.

The power supply is 2x24VAC.
I recommend one 300VA transformer.

Result is 48 Watt output in 8 Ohm.
With very low distortion.

Looking for a pair of Altec 411-8a any condition. Thanks

Thinking of cobbling together MarkAudio Pluvia 11 (7.1ohm) with a Tannoy 8" Bass woofers (4.5ohm) beneath.
The more I read on crossover design the less certain I become about how to proceed.
The bass woofers were crossed at 400hz in the 611mk2 so planned to build xover at this frequency.
Tried plenty calculators but much advice says that experimentation is more useful than the calcs.

Aside from binning the project, what would you do?

Hi all -

I took apart some of my stuff and have fs items as a result. Yes it was painful to tear them down, but it felt like the time :

Iron :
Lundahl LL1673 pair - $150 -- sold
Magnequest EXO-03 pair - $200 -- sold
Magnequest TFA-2004 Jr Nickel. 3k pri. - pair $350 -- sold
Magnequest BCP-15 pair (40h/50ma )- $100 (one of these is a little marred on the brass, but that obviously doesn't impact its performance. I always had these chokes under the hood anyway, but just pointing it out) -- sold
Magnequest B7-15k Ni pair - $140 -- sold
Stancor P-6315 - $50 -- sold
Hammond 374BX - $80 -- sold

Attenuator :
Khozmo 100k Mono MkII, Shunt - Pair of monos - $150. Loved 'em. -- sold

Tubes :
Shuguang 2a3c - $65/pair -- pending sale
ValveArt 2a3 - $50/pair
Westinghouse 2a3 - $40/pair - I barely tried them out in the amp and they work, but since I can't further test them and I don't know their hours, I'll let these go for low $ -- pending sale
Svetlana EL34 matched quad - $60/quad
SED EL34 single - $20
GE 5670 5-star - $20/pair
RCA 5u4g - $15
Tungsol 5u4g - $10
Sovtek 5ar4 - I have 2, $5/per -- pending sale
Pinnacle 6j5GT - I have 4, $8/per

maybe someday I'll dig into the mass of 9-pins I have but now is not the time. I have a ton of 12au7, 12at7, some 6n1p, 5687, 6n6p -- 4x 6n6p pending sale. If you want to ask about something I might be able to look.

On top, I'm likely using a flat rate box at $8 to ship whatever wherever in the US. Sorry I really don't want to get into international shipping with this post, but I could be convinced otherwise.

If you want to PM me with a bundle offer that's fine. I'm posting a separate fs ad with a bunch of capacitors as well. Check it out.

I only took one photo just to show the iron and attenuators in group. If anyone wants to see other individual ones let me know.

Have a great day !
-Steve

Over the last almost decade I have built numerous clones and variations of the Linkwitz Pluto and LX Mini. While I appreciate the holographic imaging design approach and results I’ve never been that happy with these designs sonically. It’s something to do with the smoothness of the top end. I struggle w ssssssssy vocals and a lack of midrange clarity, punch, impact (however it can be described) - regardless of the exact configuration my attempts at using a full range driver for the top end are unsatisfying. This is especially obvious when compared side by side with other references. However I seem to be stuck on tubes and digital XO. I’d like to get this top end issue put to rest. Any ideas or shared experience out there? I spent a lot of time trying to eq this lasted design - for only a mild improvement and now a certainty that I can’t get what I’m looking for 🙂

I am searching for output stage voltages and operating points. Specifically the KT120 SE UL and triode mode.

5K output, 400v plate to cathode, 40v bias, 100-130mA current?

Would a 300 ohm cathode resistor work? seen up to 500 ohm cathode resistors.

probably use a 400-0-400 power transformer.

or should i lower the current a bit?

Hallo There
I have 2 of these set!
I want to offer you SYMASYM To3 from Rudi
The offered set / kit consists of:

- 2 x TO3-SYMASYM PCBs
- 1 x DX PSU PCB
- 2 x Speaker Protection PCBs
- 2 pairs of well matched MJ21195- and 2 pairs of well matched MJ21196- output transistors
- 2 heatsinks 165 x 80 x 35mm
- 2 ALU L profiles 50x50x5mm, 140mm long
- 2 ERO/Roederstein MKT1822 /10µF and 2 Vishay MKP1837/10nF input, DC-blocking capacitors

The price for one set / kit is 95;shipping costs within Europe is included.


All components are absolutely new and have never been used before.
Send me a PM, if you want to have the set / kit.

Best regards - abc4230

Cut a wedge so the bevel line is parallel to the horizontal plane and attach a small stop block so the baffle does not want to ride backwards during the cut.

Attach wedge to a ply carrier board and make the cut.

Remove and flip wedge, cut other side.

I have Hypex UcD400HG amps driving my midbass in an active system. Recently I'm venturing into open baffle and I'm considering Faital Pro 18HP1010 (8 ohm) in OB to run from 50 to about 400Hz, and I'm wondering if they are a good fit because of the driver impedance at 50Hz.

UcD400HG is rated at 400W into 4 ohm, which means THD under 1%, yet THD jumps from about 0.05% starting at about 200W, or 50% of rated power.

The amp is also rated at 240W into 8 ohm. Extrapolating from the 4 ohm info, I’m estimating it must deliver about 120W at 0.05% THD. Further extrapolation into 16 ohm I guesstimate about 145W rated power and hence about 70W at 0.05% THD.

Faital has a 4 ohm version of the 18HP1010, but it is not available here. Only the 8 ohm version:

At 50Hz the impedance is about 20 to 25 ohm.

FWIW, I have subs below 50Hz, and a 5m x 10m living room where normal listening is at about 90dB SPL.

Seems to me the high impedance at low frequencies might deplete the amp capabilities but maybe I’m just getting tangled in numbers and your experience shows it would work well.

Thoughts?