I chose this project for my university assignment: Login to view embedded media . I completely forgot about the project, and now I only have 2 weeks left. To at least show that I’ve done something, I need PCB designs for ADC, DAC, and amplifier circuits. If you have any design, no matter what it is, that could help, I would really appreciate it if you could share it. Thank you in advance.

Which one of those two 1uf could be better for power and signal path application (and bypass too)?
I've used the Wima 63v 1uf (pet) with fantastic results but i've looked around and seems like that polypropylene is a much better choice over polyethylene terephthalate (pet)

Wima : https://www.mouser.com/ProductDetail/505-MKS4C041003C00KJ
Panasonic ECW : https://www.mouser.com/ProductDetail/667-ECW-FD2W105K4

I'm rebuilding a pair of Kenwood L-07MII mono blocks. They were worked on previously.

One had the 2SC1586 Sanken output transistors and the other one had Onsemi MJ15024/25.
Drivers were previously replaced with 2SC4793/A1837. Slightly slower than the originals. 100MHz vs 120. Is this close enough?

I got a second set of the Onsemis to build them the same. One amp works well but one starts clicking in and out of protection as soon as I add a source. It clicks off, then after a few seconds clicks back on, then right back off again. With no source it is usually okay but it seems there can be problems there too. Issue stayed with this block when I swapped driver boards between them, ruling out the driver boards. I then did the same with the protection boards.

I lost track of which block had the Sankens in it to begin with but I swapped them back into this site and the issue went away. But I only have one set of Sankens and want the amps to match.

Back to when I was troubleshooting with the Onsemis:
After staring at this for way too long, I noticed this amp has an extra feedback wire that going right from the amp side of the output inductor to the main feedback path to the diff pair (through a 27k resistor). So there is a feedback connection from each side of the speaker relay to the diff pair.
I tried disconnecting this and the issue went away. (But I didn't play it much like this, because I don't know how important this is and don't want any mishaps)
This wire is highlighted in the second schematic screenshot.

All electrolytics have been replaced now including the main filter caps.
I had these both fully disassembled for cleaning and couldn't find any issues or differences between them.
I'm currently testing with the dim bulb tester but it does do it plugged in directly too.

This leaves me with the following questions:
1. What's with this extra feedback wire? Is it necessary? If so, why? I can't remember seeing it in any other design.
2. Is there something about the Sankens that make them better suited for this design? And is it something I can compensate for, or do I need to track down another set? The other amp does work with the onsemis.
3. Or is something else amiss?


My understanding of design is less than the real gurus in this forum but I think I have sort of loop effect going on as this dual feedback loop creates a circle that is temporarily interrupted when the speaker relay opens. Am I on to something here?

3 questions
1---will current drive break anything due to fist order passive between low mid and hi mid?
2--will the frequency change to the point where the linkwitz design is messed with?
3---am I forgetting to consider anything relevant?

Asking because I have four channel current drive chip amp that would be great to use due to compact form factor and I already have it of course.

Any help would be greatly appreciated. I can't believe there's a place for me to ask this question and I appreciate you all for existing

The DIY ACA mini (Amp Camp Amp mini) is in the process of shipping to
the Burning Amp Festival lottery winners and a few of the helpers and
associates.

I am pleased to present the DIY ACA mini article here (in two parts as it
exceeds the size limit of the forum).

There has been at least one addition to the design since BAF, and here's
your chance to look at it again and in more detail.

I am hoping that 6L6 will provide us with one of his usual exemplary build
guides, and I anticipate more general availability of this piece in the
future, as it was intended as a low cost, easily accessed project.



----
See Also:

• ACA Mini Bill of Materials V1.1 (currently used in the ACA Mini completion kit)
• Note about how to bend the trimpot leads in the current batch of completion kits

Hello dear fellows,
I am going to make a custom power supply for AA DDE v3.0 as I acquire the device without.
As far as I uderstand this device use both rails +/- 18v and +/- 8v and would like someone to reconfirm the pinout voltages and grounds as in the service manual the pinout is showed, but voltages are not mention, nor the perspective of view (my concern) - the diagram shows device inlet or pinout of the power cable? The pinout and measurements would be the same for all power supplies sharing 6 pin DIN plug so it should be PS2, PS3, PS4, which may help us to measure and confirm pinout positions of the cable.
Can someone help me please. Would be very gtateful and rely on your extensive expertise!
Thank you inadvance!
Kind Regards
Dimitar

Nichicon bipolar muse capacitors are used to replace cheap bipolars in various manufacturers equipment.

I have done this in a DAC, 10uF 16v check out liquid audio mods for MF M1 Dac) but am aware that mkp (metalised film) capacitors would be better.

These are not available for the equivalent nichicon muse, they tend to be much higher voltage, 240v 400v etc so tend to be huge and ££££.

I've seen Wima capacitors 10uF 50v that are relatively small and not overly expensive so my question is there likely to be any improvement in the audio by using 2 of these in parallel with a nichicon muse (can be smaller value than the 47uF)? Note the mods I refer to, they put a 0.1uF wima in parallel with the muse.

The capacitor in question is a coupling capacitor.

I am starting this thread not to mix up things like I did on http://www.diyaudio.com/forums/showthread.php?s=&postid=1036908#post1036908

😀

Take a look at the thread above, which has a link to my Quarter Wave design TABAQ for the nice 3" TB drivers.

I would appreciate commments and suggestions as I am not the right person to claim "it is a nice speaker".

I am impressed, however, how much you can get out of these small drivers.

I have tested my TABAQ with TB W3-926S and W3-315SC. Both are doing well.

I am a great fan of Martin J. King´s models, and I have simulated TABAQ with TB 4" driver. On paper it looks very promising, but I have not tried it in real life.

I have enclosed the simulations.


Hi from
Bjorn

Edit (August 2022) - The following documents are added to this Post:
The First Version TABAQ Story
TABAQ Build Quick Reference Index
How the Port Length is measured

I'm sure this has been discussed in the Mid Dome thread but that thing is long and goes off on tangents like crazy.
When I first started looking at speaker drivers I did come across this driver. My first thought was "this is a crazy response. I don't really understand how this could be useful in any way"

Well, a year later and I have started to understand the beauty of this gem. Can you really use it with these lower order filters? Does anyone have a distortion measurement they could share before I dive into this? I'm open to any kind of advice on how to best utilize this dome.

Backstory behind the system: The wife has requested a system for the kitchen and I am going to design it around this. I want to keep the costs down so I'm going to use Hivi Q2R and a Dayton DA175 woofer. I'll be using lower order filters

Greetings from Auckland. Long time lurker, glad to be here.

Hello all! I'm currently repairing a Kicker DX a1500.1 which has a blown unrecognizable 6 pin ic in the power supply section. The only legible marking that's left on it is "20..."

I believe it may be a buffer ic, since it has continuity with the output pin of the UC3843B iC and the gate legs of the IRFB4110 power supply fets. Does anyone happen to know what it is? Thank you!

Hello fiends,

When I was little I started hearing in math, seeing in symbols and speaking in C C# program coding that is used in everything defined in Apple, Unreal Engine and Wwise prototyping hardware and software. But I’m an IDIOT SAVANT with DID & Schizoidice and refuse to take credit for math. But I will take a custom APPLE Studio with custom DIY everything to work from please.

https://pilchner-schoustal.com/

Martin his team and I need your help designing a custom producers suite and 3 room studio. I am no artist and hope you can share your ideas. Our main consoles will be Ian Thomason Bell Custom Tube Consoles and a custom John Hardy console tbd.

Any ideas shoot away!

I have started building my own vacuum-tube based guitar amplifiers. When one is getting started building guitar amplifiers, it is very normal for most people to buy a so-called DIY Amplifier Kit that is basically a 1:1 clone of a famous circuit such as the Fender 5F1 Champ or the Fender 5E3 Deluxe. These are both relatively low-powered, simple to understand, bare-bones amplifiers. There are many places one can buy a "Parts Kit" for one of these famous amps. They come with a schematic, a wiring diagram, and sometimes an instruction book. I would really like to find something similar to this for getting started building my own Tube-based home audio hi-Fi system.

I know that Home Audio Hi-Fi systems are more complex than guitar amplifiers on... pretty much all levels. For example, with guitar amps, the pre-amp and power amp are almost always on the same chassis as an integrated system. My research shows me that most Hi-Fi systems split these up into Preamps and Power Amps. So, I hate to ask such a newbie question but... can you guys tell me if there is one (or may be 2 or 3) very coveted and famous vacuum tube based Hi Fi kits that most people buy when getting into building their own Hi-Fi systems? I am also looking for specific sources. I've already searched the internet and asked ChatGPT; the responses are usually pretty vague, and do not tell me where I can actually buy the kits.

I have just acquired an old 2B pro... Not the lp version. I'd like to recap it and am thinking either nichon kg or mundorf gold audio. Any advice or input on these caps... Which are better and which caps (in circuit) will make an audible difference. Also wondered if the resistors would have strayed from spec. And if they're worth changing. Exciting!😀

Hello guys.

COSSOR KA31814 Lc
c b a

I got this part from an old Midas console from the '70s. It was mounted on the input module, I thing on the eq section. I have schematics for a similar module, and the only coil or inductor in the whole diagram is for a selector of 3 frequencies on the mid eq. Unfortunately the schematic is a photocopy of a photocopy of a ... hardly readable. I would like to know the specifications for this part

My intro - I'm at the trial and error level of trouble shooting and restoration of older audio. Found diy looking for some answers. Presently have a 1960s era tuner amp with some issues. Hoping to locate where to look, what to look for, and how to properly look. All things audio and electrical have interested me since I was a kid.

Nice pair of 8'' Woofer, 8 ohms, Peerless, Never used, still in their packaging.
Asking 40$CAN or 28U$ for the pair!

For Specs sheet see: http://nedlab.com/wp/wp-content/uploads/2014/06/Peerless-850130-woofer.pdf

Prefer local pickup, but can ship at the buyer expense.

Cash in person, or EMT bank transfer within Canada, Paypal FF for the US

Thanks for looking
SB

Have been working on a diy 6-24/FR EQ combo and reading and watching videos on xovers, reading the Douglas Self book on xo design, etc., but having some intrusive thoughts, lol. I don't have any formal background in electronics, so may be missing the obvious so thought I'd ask here.

In my limited research, I never ran across the anyone asking if a passive crossover circuit board could be used in an active stage (for a commercial speaker it was designed for and integrated and sold with, of course) . I'm assuming there might be buffering required at inputs and outputs to account for impedance differences, or need to have a strong drive due to insertion losses or larger components, perhaps more noise, idk, but I'm wondering if it's theoretically possible.

If so, I'm assuming there must be caveats that keep doing something like or a scaled version this off the table as a recommended approach. (other than opportunity loss for other active xo benefits like custom/complex filtering via circuits or dsp). Perhaps the level of effort to convert vs just starting anew?

My lay thinking is that small line level AC signals should act identical to large amplified AC signals, challenges for each extreme aside?

Would something like this be theoretically possible?
if so, what are the downsides?
Mighty there be some potential for transferring inductors or other very specific/custom/proprietary components to the active stage when transitioning from passive to active?

Initially I received a schematic from one of our colleagues here, with a choke as load for the THF51 SIT transistor, capacitor coupled with the speaker. Since my trade is audio xfmrs I modified the schematic replacing the choke with an output transformer. I've added also an 1:3 input xfmr. Any comments are welcome! Thanks!

Many thanks to the great members here, Planet10, GM and Scottmoose for the help in figuring out my next fun project, been a long time since I built a pair of speakers.
Long time fan of tube amps and horns so this is just a bit of a different approach than my great Edgarhorn, highly upgraded, Slimlines I just cannot use in our RV, sadly so,

It might be awhile before I can build them as in the middle of an all out rebuild of the big 5th wheel, including adding 18" to the rear length so I had room for a decent system and adding a second entry door.

Plans:
I was looking into a solid walnut front with rounded over corners, BB or maple ply for the rest but now considering all walnut or possibly straighter grain ply with 45 degree corners all glued up, a bit tougher construction but I think I can manage with my decent Makita portable table saw that has virtually no run out and mounted to Roseau fold out tables, bigger fence, etc.

System
Ethernet into WIIM Ultra streamer
Topping V70 Velvet DAC (will look into other DACs later on)
Baby Sophia 10 watt push pull tube amp with upgraded terminals and all caps.
FH Joan with MA200
Conare DIY wiring

I am hoping to not need a sub, music only system, not for movies as we seldom watch anything on the TV.
If sub(s) needed I planned to use the two Image Dynamics 15's I have in storage but the would be a bit of a fitment issue with the big Joan FH speakers.
I could probably fit the.....forgot the name, little triangle shaped subs that go up against the wall behind the mains.

I might get into building a tube front end D class amp, possibly DAC, etc, in the future as well.

Really looking forward to finally having a good system again, been years since had the space to do so, full time RV for over a decade now.

Rick

Selling my HP 8903B Audio Analyzer, in great working condition. This is a solid piece of test gear for anyone doing audio measurements like THD, level, or frequency response.

$500 USD

This forum is as a good a place as any for thinking out loud about the successor to the Ariel and ME2's. Since my fall in the terrible Colorado snowstorms of January, I've been recovering, and probably won't be doing any serious audio design until the summertime.

But I can still think and write, and have been making occasional posts in John Atwood's Clarisonus blog. One perennial question I always get is how to build an Ariel with XYZ drivers (and of course a different crossover and cabinet). As mentioned in my Web page, it take me about six months to design a speaker, and isn't something I do on a whim, or something to "use up" some drivers that are lying around.

The Ariel is now about 12 years old, and my tastes have changed a bit in the meantime. No, I'm still not a fan of horns, even though the horns I've heard here in Colorado are some of the best I've ever heard anywhere. Fabulous micro and macro dynamics, but I still have reservations about tonality with classical music, especially the big-scale choral music I enjoy so much.

The speakers design I'm exploring these days are large-diaphragm dipoles - hearing both the Linkwitz Beethovens and the Bastani Apollo was a revelation about the dipole/open baffle sound. Interestingly, both the Linkwitz and Bastani designs get to similar place via completely different methods: Linkwitz with extensive equalization and multi-amping with high-power transistor amps, and the Bastani with extensively modified 12" near-full-range drivers, and a subwoofer and supertweeter to fill out the range.

Both the Linkwitz and Bastani have stunning dynamics - almost in horn territory without the colorations - and the spaciousness and 3-dimensionality of electrostatics. I can see why many Europeans are turning to open-baffle designs: they do things that never happen in conventional speaker boxes.

Of course, there's never a free lunch: dipole speakers have unique design challenges all their own. The most obvious is the tilted frequency response that starts a half-wavelength below baffle width. Linkwitz attacks this with multiple crossovers, multiple drivers, and complex low-level equalization, which straightens everything out again. Bastanis, by contrast, stretches a single 12" driver to its limits, and helps it out below 220 Hz and above 8 kHz with a subwoofer and tweeter.

What I'm contemplating is a bit of both and a little different: a prosound 12 or 15" coaxial driver, with efficiency of about 97 to 99 dB/metre, and a supplemental 12 or 15" driver that comes in below 160 to 250 Hz (switch-selectable to match room characteristics). The upper driver runs full-range, and is acceptable with any Qts. The lower driver has a Qts from a 0.6 to 0.8, and carries the bass in the region where the dipole 1/f effect starts to be significant. Below 80 Hz, bass is carried by stereo subwoofers in close proximity to the dipole array, and the subwoofers are independently powered by their own amplifiers.

The dipole array as I'm imagining it has either 2 or 3 drivers: one full-ranger, of very high quality, and one or two bass-fill drivers, with tapped air-core inductors adjusting the overlap region. Dipoles in particular need to compensated for room-response, due to their unusual radiation pattern, and the inability of the user to optimize imaging and distance from the wall/corner at the same time. By adjusting bass-fill driver overlap and subwoofer levels, the response in the 20 to 500 Hz region can be optimized for the room, without compromising image quality (which is controlled by the mid and HF response of the driver).

Yes, this is very different speaker than the Ariel, although I hope to retain the midrange spaciousness and natural voice quality in the new design, along with a 15 to 20 dB increase in dynamic range.

---

75For the current state of this project (known as the LTO) see here:
https://production.diyaudio.com/community/index.php?posts/3189501/
And here:
https://production.diyaudio.com/community/index.php?posts/3190604/

---

75

I have an 18inch subwoofer that the magnet has slipped and I need to glue it back into position. I have re-aligned it into position and I have a new re-cone kit for it ready to be installed.

What’s the glue that factories use?

I have a tube of loctite 324 and it’s used to glue magnets into electric motors and metal etc…. I was wondering if that would bond a speaker backplate to the magnet? The magnet has a lot of wait to it being an 18inch

Cheers
Hayden

Hello everyone,

I’ve got a collection of old 8mm films from the 70s that I’d love to preserve digitally. I’ve heard of various methods and services, but I’m wondering what’s the best way to go about this. Specifically, I’m curious about the process of converting Super 8 to digital. Should I invest in a DIY film scanner, or are there professional services that offer high-quality conversions?

I’m looking for a process that maintains the film’s color and detail as much as possible, especially since these films are pretty sentimental. Any tips or experiences with the conversion process would be greatly appreciated!

Thanks in advance!

Lets imagine 2/3way speaker with 25-30mm soft dome tweeter. Most of soft domes does not perform very well 10kHz+ offaxis. We can control directivity with the waveguide, but 10 kHz+ we dont have enough energy offaxis. There are some harddome tweeters with good behavior, but they are expensive.

My idea is - what if I will add two small 16-19mm tweeters (cheap ones) aiming to the sides (or rear/up/down...) and cross them at 10-12 kHz to make directivity in that region as wide as possible (add energy to reflections)? If done well, it will have little influance on the direct sound.

How it will sound like? Is it beneficial?

Can we localize direction 10kHz+? What if those extra tweeters will not be nearby main tweeter?

Absorption in typical room is usually high at those frequencies - will we hear the difference?

I know that it's some kind or website reformatting, and not me, which had suddenly changed some months ago: Now, almost every time I paste a forum webpage link into a PM chat or thread chat what gets pasted is not the URL but someone's user logo and lines of italicized text which I never intended to quote from that page. This new and improved whatever is making a total mess out of my posts, like here at #15695.

Please put things back the way they always were!

since we have an electronic music thread it would be sad to not to have a rock music one. i will start this one with something from 2020 (no disrespect for the 60ties 70ties rock). please put some here that you think people should listen to.


Danny Carey | "Pneuma" by Tool (LIVE IN CONCERT) - YouTube

Hi everyone! I'm a college senior building a dual-18" PA subwoofer as a school project and a way to buff my portfolio. Here are the transfer functions and WINISP stats. The sub uses Colussus 18B woofers and will be tuned to 28.5Hz. Theres is a shoddy drawing attached of the design, these graphs are for 1 driver(1/2 of the full design). I apologize for the poor drawing, I've been struggling to use modeling software. If anyone has any feedback, I'd really appreciate it, though keep in mind that this is extremely limited by budget! I'm also looking for FOH/Sound technician gigs in Nashville, if anyone knows of any!

I've been looking for a decent tone control preamp and have tried a couple Chinese boards that were awful. I was considering the ESP HiFi preamp but this was deemed a poor design as discussed on a different post.
This is another board kit I found which has decent specs. The balance control was added by me but not sure if that's the optimal location.

Ma name is Franek. Love DIY from many years

Hello all, I'm a retired electronical engineer, mainly trying to repair some hi-fi equipment with schematics, ready to discuss all. Thanks

Hi everyone! I'm a college senior building a dual-18" PA subwoofer as a school project and a way to buff my portfolio. Here are the transfer functions and WINISP stats. The sub uses Colussus 18B woofers and will be tuned to 28.5Hz. Theres is a shoddy drawing attached of the design, these graphs are for 1 driver(1/2 of the full design). I apologize for the poor drawing, I've been struggling to use modeling software. If anyone has any feedback, I'd really appreciate it, though keep in mind that this is extremely limited by budget! I'm also looking for FOH/Sound technician gigs in Nashville, if anyone knows of any!

It's been so long since my open baffle system was completed and honestly, due to famiy and living situation, I don't get to enjoy it as much as I used to. It's time for something scaled down and yet possibly MORE precise, MORE stunning and natural to listen to. Something I can fit comfortably into my bedroom and not disturb the wife and kids, but can't be headphones, as I can't last more than maybe an hour with headphones on, no matter how lightweight and comfortable they are. It's got the be real speakers with imaging.

I've got most of the design sorted out, but not sure what to do for the woofer/sub. Likely want it to be open baffle and as simple and light as possible, but open to options from y'all. Maybe a pair of something mounted totally naked, as the planar and midbass will be, but not 100% settled there. Looking for options with a QTS around .5-.7, low FS and 4 Ohms. Hit me with options regarding drivers or other novel designs for bass, either store bought or DIY. Could also just buy the dual Rhythmik 8" kit and mount that somehow. More concerned with clean, tight pitch definition than the last ounce of extension.

Photo of original system for comparison sake followed by photos of inspirations for this project.

4 pieces PF-XTI AL pio caps from Ampohm.Used for short time but top condition.No more in production but one of the best out there.Price is 60 euro plus shipping.This are 0,47uf 600V typ.This are big so you must have place for this verry good caps.They are 25 x 60mm dimension.Sound test online.Payment by Paypal.

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Is this the same concept as to why ‘corner deflectors’ and small shapes inside subwoofer qw pipes (and fold dimensions) do ‘nothing’ helpful to the long 1/4 and halfwave lengths, etc?

Hi Thanks for reading. I need help with an open baffle speaker. I am using a B&W driver in a sealed box to reproduce the low end as I do not have the space for OB bass, xover frequency of 400hz with second order rolloff

The mid is minimalist OB visaton B200 which a lot of people seem to like, and finally a B&W tweeter with a 10khz crossover

The two B&W units sound good but the visaton is beaming and boring to listen to. What driver would you recommend to swap out for the visaton. For every drive unit that holds promise, I then read reports from a ton of haters. Lowthers were reported to be good but then in other posts haters tore the lowthers to pieces

I have tried filters and phase plugs with the visatons but am still not happy

Using the BA-3 gain stage (“Front-end”) as a line stage preamp. A mini build guide. 🙂

PCB - P-BAGSN-1V20 - Burning Amplifier Gain Stage for BA-3 (Requires bias boards and output stage; Makes 2 channels; Rev 2.0) - Circuit Boards

BA-3 as preamp thread - http://www.diyaudio.com/forums/pass-labs/234641-ba-3-preamp.html

A club in Minnesota that used this preamp as their club-wide reference! https://sites.google.com/site/audiosocietyofminnesota/Home/diy-projects/pass-ba-3-preamplifier

The BA-3 front end is able to act as a wonderful preamp, with plenty of gain that is changeable with just a few resistors.

You will need a power supply, selector/attenuator, and chassis.

The chassis used in this build is the Galaxy 388 from the diyAudio store. Galaxy 388 (3mm Front) - Compact with Quasi Heatsinks - Chassis



Schematic of signal circuit.


Any project needs to start with a good PSU - this is an Antek 20+20V shielded transformer, and 317/337 linear regulator PSU from Tubecad.com. (Model PS-12) Of course you could use the Super Regulator V2.2 from the diyAudio store. Super Regulator V2.2 - Power Supplies and Accessories - Circuit Boards Look to the support thread to see the changes for 24V operation. (I didn’t use the Super Reg as that particular PCB wasn’t available when I ordered all my stuff…)


The back panel is very straightforward, IEC, and RCA jacks.


The inside of the front panel shows the three-input selector switch (Tubecad.com Select-2) the stepped attenuator (This is a 50K Goldpoint) and the AC switch (Tubecad.com AC switch)


Transformer wiring shown here - IEC (which holds the fuse) to the AC switch, then to the transformer primary. Transformer secondary to the PSU board. (configured as a center-tap) The purple shield lead connects to the same point as AC mains safety earth.


I used small coax cable for signal wiring. (actually stripped out of a long S-video cable) Each ground and signal is switched. Another very good choice for signal wiring is twisted pair from a cat-5 cable.


Switch wiring.



At this point the input wiring, selector switch, attenuator, AC, transformer and PSU input are all complete.


PSU output wiring.
Also (not shown) I took a LED and resistor from V+ to gnd to act as a power indicator.



BA-3 gain stage (Front-end) PCB. Note that there are PSU connections (V+, V-, GND) for each channel.
Also raise resistors R10 and R11 as shown, you will need to clip test lead there to set this stage’s bias and DC offset.


Completed FE board.




If you connect the BA-3 power wires to the back of the PCB they will be out of the way and closer to the chassis - two birds, one stone. Also in most of these photos, R2 is not installed. I later put it in and the attenuator switching pops went away.


Again, please install R2. In this photo you can see where I attached the signal ground. The ‘G’ pad has the PSU ground attached from the bottom.


Completed preamp back.


Front. (The power indicator LED is not shown.)

Hi DIY's,

For decades I am reading about the great sounding LAT FET's.
There are a lot of simulations(Lineup) and builds.

I am a fan of opamp error correction and like to use it to lower distorsion and noise.
Further having about a 100Watts at hand is what I also like .

Goal:

• 75...125Watt at 8ohm
• THD < 0.0001%
• Noise < -120db
• SMPS power supply

Now comes the help I need.
Schematic below is a combination from Elliott P101 output stage and an opamp(OPA627,LME49710,OPA1611,OPA1655).

• Does T1 have enough( 3x) voltage gain?
• Is the feedback(R4/C4) fase correct connected to opamp?
• Is there enough compensation to make the amp stabil?

Hopefully can someone simulate this schematic and give answers. I have tried several times last decades to use TINA and Spice without satisfying results.

Thanks Ronny.

Updated 27-2-2025





Latest version

In its June 2018 issue, the "audioxpress" magazine published my article about a Turntable Speed measurement device (as shown in the photo).
The device is based on a microprocessor ATMEL ATMEGA328-PU and was developed with Arduino software.
Due to copy rights I cannot post the article here but if someone has access to the article and wants to build the device I have some pcbs (as shown in the photo) and programmed CPUs for selling.
The price for both PCB and programmed CPU is 24 Euros (shipping cost is included in this price).
If someone is interested send me a message.

Hello.
I'm thinking of making a two-way with SB17nbac35-4.
Would like help with the volume on the box. Don't know what type of box is suitable. Bass reflex or something else.
Feel free to make suggestions.

I completed my SSE several years ago...everything is good, no problems. Still using the 6CA7 fat boy Electro-Harmonix outputs. I have been experimenting with the 12AT7 and it's variants to determine which type suits my setup best, as in delivering the best sound. I know this is subjective, and highly dependent on all aspects of the amp and it's associated equipment. I have a couple of favorites, but I'm interested to know what other SSE owners have found to be "best". Also, if any found types not compatible with the standard 220-ohm cathode resistor.

1 year old, bought on audiophonics.
Price 100e + shipping.

"Design Phase - 2 Monster Front Loaded BR Subs"



I would like some input, lots of it in fact, to help me design a pair of monster front loaded bass reflex subs for filthy techno rumbles.


The only criteria so far is the drivers be 18inch, 4 ohm nominal impedence and somewhere in or around the region of 1600w RMS/AES each.
I have some ideas but ultimately, they will bee housed in 2 front loaded 25mm MDF cabinets with two huge huffing round ports "down below and out front".... as they say.
Well, that's about it really.... Everything else is open to discussion



So, we might as well go straight off the bat, this particular driver is wetting my whistle and most likely the model I would have chosen....
https://www.eighteensound.it/en/products/lf-driver/archive/18lw2500
https://loudspeakerdatabase.com/18Sound/18LW2500


This beast was also a contender but after much searching and reading it turned out to be out of stock everywhere.
https://leanaudio.co.uk/product/celestion-cf18vjd-4-ohm-18-1600w-loudspeaker/
https://loudspeakerdatabase.com/Celestion/CF18VJD
You know what's funny.....? There are no listing for the 4 ohm version on Celestion's website, nor the loudspeaker database.
And then I read in a thread on another forum somebody stated that there is no 4 ohm model of this driver.

But then I came across this ----->
https://www.gear4music.ie/PA-DJ-and...D-18-Low-Frequecy-Subwoofer-Driver-4-Ohm/2O08
https://www.gear4music.ie/PA-DJ-and...D-18-Low-Frequecy-Subwoofer-Driver-8-Ohm/2O0D
Has the 4 ohm driver been discontinued or did it ever exist at all.... Are the 4 ohm models just plain misquoted or misprinted....?
Can anybody confirm this for me....?


And then I found these ----->
https://faitalpro.com/en/products/LF_Loudspeakers/product_details/index.php?id=201070141
https://loudspeakerdatabase.com/Faital/18XL1600_4Ω/Faital_18XL1600_4Ω.pdf
Very impressive.... But also very expensive !!!


It looks like my choice of drivers will more than likely be either number 1 or number 3
Has anyone got any experience or opinions to add, I sure would love to hear them if you have.



Next up, enclosure design and build.

Cabinets will be built with the intention to last 100 years in keeping with the "speaker from scratch" thread
https://www.diyaudio.com/community/...-design-your-own-speaker-from-scratch.332688/
I will be following this thread carefully and intend to remain true to it's principles to the best of my ability.

I found 2 sets of enclosure plans, one for the 18Sound 18LW2500 and one for the Celestion CF18VJD.
I will attach the pdfs to this post.
The 18Sound design has an effective volume of 177 litres yet I read somewhere in their literature that the recommended
enclosure size is just shy of 200 litres.
The plans from Celestion quote an effective volume of 167 litres so these two drivers of similar spec would appear to need
an almost identical sized enclosure.


This is where my questions begin.... Will it hurt if I go bigger....?

Size is not a problem here, volume and sound quality are far more important to me.
I am just about to model these drivers and a few different boxes in WinISD but I would really love to hear what some of you guys have to say.

Oh yeah, and one more question for now please.
What is the best crossover point for bass heavy, earth shaking techno....?
Once the build is complete I will begin my testing at the standard 80Hz
That will do for now, I will be back here regularly to check in, post my progress and share my journey with interested members.



/DATABASS

This relatively simple upgrade was on the to-do list for ages.. 😴

I finally put them in, and did a write-up + pictures at: https://www.pma560.com/terminals

I have a very old Sansui A-40 that has all the amp output and driver transistors blown (seems like a weak design) ... maybe more...replacements are hard to find and expensive. Do you think I should go through the trouble and expense to repair it or scrap it for parts. It has a nice transformer I could use but that is about it.

Hi,

i have created a draft for an input selector that should switch 4 Toslink and 1 Spdif input to one output at cmos level. The switching itself should be done by HC151N. Dout is going to a Teensy4.0 SPDIF_in, the IC will be controlled by that Teensy via the IO-lines. I would like to ask for your support to find some mistakes or improvements, because. This is only my second pcb design and I am not experienced in this.

From my point of view, it would be better to decouple the Spdif_in by transformer, but which one to choose and how to connect? Should i pull down the IO-lines? Anything other to criticize?

Hi, Everyone.

So I have a simulated response in XSIM based on measurements I have taken of my loudspeaker. I won't go into detail on how I arrived at the measurements but they are accurate.

My simulated crossover and the actual real life measurements of the loudspeaker after the crossover was implemented are different. After some manual tweaking I got the crossover where I like it, and then re-did my crossover in XSIM. Obviously, the measurement part of XSIM is not accurate to real life.

Here's my question, is there a way in this case to take my measurement into XSIM and essentially teach it to to say, with these crossover components these are the actual measurements and then tweak it further from there?

Cheers,
Joey

Hi everyone. I have a Neutrik A1 audio analyser that I recently bought. Unfortunately the power supply is faulty. Does anyone have a service manual with schematics for the unit please? I have looked throughly on line with no luck.

Thanks,

Mike

Hi, I bought it many years ago and recently power supply relay started to on and off, sometimes It works 2-3 minutes and the same problem occurs, any advice?

These are "raw" High quality american walnut wood frames + 3 mm thickness aluminium top plate + perforated aluminium bottom plate.
Dimensions are:
390 mm x 450 mm x 80 mm.........3 units
260 mm x 580 mm x 80 mm.........1 units

Price per unit ......140 euro + shipping anywhere......
Thank you.
I use it on these projects:
https://www.diyaudio.com/community/threads/el34-baby-huey-amplifier.326920/post-7380662

The record player "Alamo" from Moth is a good known record player (nearly identical to Rega Planar and NAD's 533.
But I have an other model from Moth. Typ: "Kanoot" Unfortunately there isn't similar type from other companies.

The actually device in correct working condition has on problem: the motor pulley's sizes (for belt) is made for the British marked (mains frequency 60 Hz instead 50 Hz).
Therefore in Germany the RPM value isn't right.

Where I get such motor pulley for 50 Hz (to replace the exist 60 Hz version)?
Motor model is follow: SAJA MURTEN UDR11UJ1RNZ32 (SWITZERLAND) - go to second image from post #13, also used in Revolver turntables and some other.

I have now realized another solution to avoid having to laboriously remove the 60Hz pulley and replace it with a 50Hz version.

I remove the capacitors at the motor and introduce this motor control unit (clone from Dr. Fuß) - often incorrectly referred to as a power supply :
Homebrew Motor Control Linn LP12 - Circuit Description wanted for Sine Wave Osc.
To the resistors R28 and R27 I add a 27K resistor in parallel (have a look in the PDF schematic of post #16).

This works perfect together with the 60Hz pulley. The target speed is now (only at 33) a bit right of the middle position of the speed controller knob.

The old address from Moth is follow:
Moth Group
Tel: 01234 741152
10, Dane Lane, Wilstead, Bedford, Bedfordshire MK45 3HT
and the related URLs here with some history of the Moth Group:
British Audio Products Online - About Us
British Audio Products Online - About Us

I am planning a 4 way build. A little bit of an unconventional one (like always with me)

I am looking for a really small dome tweeter. The idea is to get a really like spread of sound throughout the room and the smaller the tweeter, the higher the frequency it falls off. At least, that's how I currently understand it. Feel free to correct me.

I am looking at this Peerless unit and wonder if there are any other small diameter dome tweeters I should be looking at.
https://www.parts-express.com/Peerless-D19TD05-08-3-4-Poly-Dome-Tweeter-264-500?quantity=1


Just for reference, the idea here is to match the octave to the size for proper spread.

8-10" woofer 35-350hz
200-1000hz - 6.5-7" woofer
750-5000hz - 2-3" dome mid
4000 - 20khz - Small diameter dome tweeter.

I believe the diameter of the driver plays a very large role in when the frequency response starts to drop concerning off-axis. Here you see this very tiny tweeter doesn't drop off axis until around 9000hz. So if I stay within the proper octave of the diameter of driver I can basically have an even spread across the room and it won't matter where I happen to sit.

If you have a recomendation of a small tweeter, I would like to hear it. Thanks

As I just released the DDDAC1794MK3 series (Dac and PSU) I thought it might be a good idea to set up a support thread for technical and background question, discussion and support.

The release post is here: http://blog.dddac.com/the-new-dddac1794mk3-dac-and-psu/

For those already interested in the construction and installation manuals:

DAC: http://blog.dddac.com/wp-content/up...tion-DDDAC1794MK3-DAC-Version-2.6-rev-1.4.pdf
PSU: http://blog.dddac.com/wp-content/up...ction-DDDAC1794MK3-PSU-Version-2.5-rev1.4.pdf

I am not a great photographer, nor do I have a product photobooth, so here is a somewhat lousy picture of my test set-up:

• Power transformer 2x12 Vac
• double DDDAC PSU
• two AE Chokes (my specs: Amorphe 1H 4 Ohm)
• DAC Board DDDAC1794MK3
• Sowter Output Transformers

looking forward to some good discussions 🙂

Doede
http://blog.dddac.com/

Because in a previous stage of the circuit I am trying to eliminate what is common to both the left and right channels of a stereo input - typically voice - I have to consider that I have dropped off some bass. So I figured I would (optionally) include a low-pass filter in hopes of increasing the presence of the ~70Hz range.
Am I fooling myself?

I want to know about the subjective sound quality differences between these three drivers, if they all three are placed in an optimal cabinet .

Are there any differences and if they are, in what way ? What are the differences with these three units placed in optimal boxes, regarding SPL ?

I have the chn110 for the moment and its a very good sounding driver

As a long-time technical person, very passionate about music and currently producing media music - server devices for smart audio systems.

Hello, I'm currently finishing a new amplifier, but unfortunately this time I'm having a ground loop problem between the two channels.

When I finished the first channel, I didn't have any hum in speaker. It was when I added the second channel that a hum appeared, and I was able to test, as indicated in this document, that this was indeed the problem.

https://hifisonix.com/wp-content/uploads/2019/02/Ground-Loops.pdf

I was able to improve things by modifying my wiring, but a slight hum persists
in the test speakers.

I'd like to add this Hum Breaking Resistor (HBR) if possible, but I admit I'm not sure where to place it.

Here is the amplifier schematic:

Here i have for sale 120pairs of Toshiba 2SA1360Y/2SC3423Y (NOS) excellent drivers for VAS (Voltage Amplifier Stage) as they have lowest Cob and highest linearity gain over Ic/Ib (hFE).

Price offers can do on my PM.

It’s time to rewire my espresso machine. Most of the internal wiring, including female spade connectors (Nomenclature?) and woven hi-temp insulation is in pretty rough shape. Do any DIYers out there have experience working with equipment that makes steam? It seems to be a pretty hostile environment for metals. My problem is that I need some wire, insulation, and connectors. If I knew how to specify these things I would just order some up from one of the usual suspects in Texas or Minnesota. The search engines on those sights always feel very awkward to me, probably because I’m not an engineer. I could probably source the stuff from a local appliance parts shop, but I don’t think that would really qualify as “ essential.“
Thanks in advance,
Hal

Hello. Have you ever experienced any issues with the left amplifier channel?


I also installed Toshiba transistors, type 2SC5359 NPN and 2SA1987 PNP, but I’m having a problem with the left channel.
Actually, I’m not even sure if it’s the left amplifier — the orientation is reversed for testing, so what appears to be the left side from the front becomes the right side when the amplifier is flipped over (viewed from the bottom, with the legs up).


Anyway, here’s how I’ll explain it:
I slowly raised the voltage using a variac and measured the bias points TP1 and TP2.
I’ll describe it as seen when the amplifier is upside-down.


On the right-hand side (which would be the left channel from the front), everything worked fine. The relay clicked on, voltages were around 85.5V, maybe a bit higher, measured between TP4 and TP5.
The right channel works fine, and the bias was around 30mV.


Then I connected the AC voltage to the left channel.
Even during the slow power-up using the variac, I noticed some anomalies:
At just 30V AC input, the bias already jumped to 60mV.
At 50V AC input, the relays clicked on, and the bias jumped to 160mV — which is way too high.
The VU meter for that channel also jumped to the middle. Something clearly isn’t right.
I quickly powered it off to avoid burning the main output transistors.


What do you think I should do? Should I swap the driver boards from left to right to test?


I suspect this issue might have damaged the original DLPT transistors.
Before installing the Toshiba ones, I had installed new old stock DLPTs, which the technician burned out — the same issue occurred back then. He wasn’t able to find the cause.
That’s when I decided to go with the Toshibas, but now I’m facing the same problem.
I really don’t want to burn out another set of transistors.


Where should I start troubleshooting?
Thank you for any help you can provide.

Everything is in excellent condition after minimal use, though the batteries have sat around for a bit. I really need to get rid of these and I don't know how/where to sell. Waiting for offers!

The batteries have combined terminals, meaning the same wire is used for charging and discharging. A secondary wire terminal is a sensor used in conjunction with compatible NiMH smart chargers to prevent overcharging. The primary connector is a molex and the sensor is BEC. The battery also has a built-in thermostat to protect it. If needed, you can change out the connectors for your preferred type. Originally purchased from BatterySpace.

Included in the auction:
(2) Powerizer 24V 4.4Ah NiMH batteries (EB-HSC20R3TM45-V2)
(1) Powrizer NiMH smart charger (3PX0-24V1.8A)
(1) separate voltmeter to check battery charge
some extra cables (XLR to molex/BEC, etc)

25W Single Ended Hammond 193V Choke Loaded 2SK180 L'Amp

(35W @ 8 Ohm if Iq increased to 3.0A)

I'm a great fan of VFETs and SITs. I've built the Papa Pass diyAudio Sony VFET amp, Michael Rothacher Sony 2SK28 Hammond 193V choke loaded L'Amp and Luminaria (2SK82) preamp, Zen Mod SissySit with THF-51S, and Pappa Pass BAF2015 amp with THF-51S. Prior to these amps, I had tubes for many years - single ended parafeed 45 amps and filament biased 26 preamp. But I don't miss those tubes. It's VFETs and SITs all the way now, thanks to Papa Pass, Michael Rothacher, and Zen Mod.

So last March when I was looking for another project,Tokin 2SK180s were readily available on ebay. Since I didn't have any amps with them I decided to buy a couple and give them a try.

I decided to use the Hammond chokes from my 2SK28 L'Amp for this project and redo the 2SK128 L'Amp in the future with a mu follower current load. The amp was built into one chassis and it was very heavy - I could barely lift it. So it went through a weight reduction, and its 193V chokes will now be transplanted to bring new life to a pair of higher powered 2SK180 monoblocks based on Michael Rothacher's choke loaded L'Amp design. I really do like the single ended sound.

Since I couldn't find much information on the world wide web on operating points for higher powered choked loaded single ended 2SK180 amps, I had to figure something out. The other factor was that Tokin SITs have a large variance in their characteristics so even computer similations would not reliably predict good operating points. Despite that I did do some LTSpice simulations for the fun of it.

Before I could do live tests to figure out the operating point that I would use, I built some chassis to mount the Tokins and keep them cool. With all my previous projects, I had purchased ready made chassis. However there was a lack of ready made monoblock chassis with a single large heatsink, so I decided to purchase some aluminum plate and angle and build my own. I don't have a work shop or drill press but I made do with hand held tools, working in my kitchen, and now I have two reasonably presentable monoblock chassis.

All circuits are point to point wired on perf board. The actual signal amplification circuit is very simple, with minimal parts. The majority of the parts are in the bias supply and in the yet to be constructed V+ supply.

To be continued.

Edit: Power Supply

Edit: 2021-04-04 Added Information - Amplifier changed from Common Source to Common Drain (Follower): Common Drain (Follower)


Edit: V-Power Supply Version with PCB added:

- Start of V- Supply Version Posts

-Post #685 Building Tips for V- Power supply Version

-More Tips

Edit: V- Power Supply Version with PCB, with Independent Bias Voltage Supply to Suit SMPS V- Supply

- Independent Bias Voltage Supply Version

Edit: 2024-05-01 Follower Version - Increased Iq to 3.0A, Lower Distortion and 35 Watts Output

-Higher Iq, 35W @ 8R

- By the way other Tokin SITs such as the THF-51S or 2SK182ES may be used in place of the 2SK180 in this amplifier.



Original Common Source Amplifier Below:

THIS LINK IS ON EBAY :
https://www.ebay.it/itm/365439158624
https://www.ebay.it/itm/365439158624

I have all components needed to build Wayne Parham's 4pi speakers. Includes the following:

2x JBL 2226H woofers. One buzzes and needs to be reckoned (kit is $99 from Simply Speakers). $250 for the pair
2x: B&C DE250 drivers. Bought new and include original boxes. $200
2x: H290C horns. Purchased from Wayne. $80
2x: Assembled crossovers. Boards were purchased from Wayne, components from Parts Express. $100

Willing to sell individually, or $500 for everything. Local pickup preferred (San Francisco), but will ship FedEx ground at buyer's cost. Photos to follow Sold

Hi All,

I got a 12Vac single tube (6N3) Chinese tube buffer (schematics attached).....or at least this is how the Chinese market it.
I would like to know please if it does act as a buffer (it is a unity gain circuit) so it can be used for "impedance matching".
I will bypass the input potentiometer, probably increase the input capacitors value a little and change the output capacitors for a better quality ones.
I'm using a 15Vac transformer so the DC voltage is about +/-42Vdc and not 30Vdc as in the schematics which put more "stress" on the 7805 regulator so I might also change it for a 7806 regulator.
One thing that is a bit of a mystery to me is that even when I remove the tube completely I still get very low sound output, I assume that the signal still go through the 470K and 470r to the output.

But first I would like to know your thoughts about this "buffer" as a buffer, any comment related will be appreciated.

Hi!
Does anyone have any experience or measurements of the Douk Audio A5?
Thank you!
D'

For Sale:

Discrete R-2R DAC Hat for Raspberry Pi ( Version V2.42 )

Up to 24bit 384K, non over sampling .
Support Pi 2,3,4, and 5
Distortion 0.004% ~0.005%
Price: USD196.00

The difference between this V2.42 ad older V2.4 :
V2.42 using larger FPGA and most of the job has been done in the FPGA.
No MSB adjustment preset required.
The PCB size is the same as Raspberry Pi, so that I can install \ modified a raspberry pi tower case
Support Pi 5


Shipping via FedEx Priority International, to USA = USD34.00 , Canada = USD32, Most of Europe countries = USD35.00

Please PM if you are interested, Thank you.

** Edit 2 August: Just finished assembling another 5 pcs and available for purchase **

I like building HiFi speakers. Recently I became enthralled with the concept of open baffle. Where can I find concise information on what specifications I should be looking for with regards to a 10" or 12" full range or coaxial driver? Any recommendations for drivers around $150 each? Are there any online DIY plans or websites I should be looking at? Thanks in advance!

I'm looking for one RSS390HE, if you have 2 and want to sell as a pair, I will take both. I'm located in Oregon

Hi,

I’m looking for a new soldering station, I currently use a Metcal MX5210 which I’ve had for a long time.

I’ve been considering the Weller WXSMART series, but it seems like I’d be paying for a lot of smart features I don’t need.

Any recommendations, no real budget in mind.

I would mostly be working on cables.

PREFACE:
It is my opinion that the only legitimate use for piezo drivers in audio is as a Super/Ultra tweeter. Their full range output is quite nasty and not HiFi.
They are however very fast, hence their use in ultrasonics.
THE GOAL:
To augment speaker systems that drop-off around 14Khz, and/or a method of helping older people with a degree of high frequency hearing loss.
To achieve this with a minimal amount of 'overlap' with existing tweeters that would cause H.F. 'smear & comb filtering'.
PICK YOUR PIEZO:
All the drivers I have investigated for this project are non Motorola current generics. You can try any piezo, but I recommend the 95/98mm circular horn that is available on Ebay for about $10 a pair. I was quite surprised to find that my pair were excellently matched in both capacitance and output.
THE PARTS and CIRCUIT:
Excluding the piezo drivers, there are only 4 parts required per Super Tweeter. In Australia the cost per Super Tweeter is about $50. (the U.S. would be less)
For the sake of simplicity, all components are standard value parts.
The heart of the 'drive/filter' is a 5W audio line transformer, used in reverse.
Find the 8 ohm side of the transformer by measuring the wires (or terminals) that are less than 1 ohm DC. This side of the transformer connects to the amplifier via a 1.5uF (high quality) capacitor and 2.2 ohm 5W resistor in series with one of the wires. This completes the input to the transformer.
( facing both sides of the transformer, the right-hand connection is 'POSITIVE' )
Now, on the other side of the transformer find the two terminals next to each other that measure about 40 ohms DC. (all other terminals should be ignored)
These '40 ohm' terminals directly drive the piezo WITH a 1.5mH inductor in parallel. This inductor does not need to be an expensive heavy duty type.
That's it - circuit complete.
FINAL RESULTS & THOUGHTS:
For this project, 15Khz can de considered a reference point. It is where the 'filter/drive' has peak output and also where the impedance is 8 ohms.
Above 15Khz , 18Khz is -2dB, and 20Khz is -2.5dB.
Below 15Khz , 10Khz is -5dB, and 5Khz is -23dB.
This means we have achieved a true 18dB per octave/third order cross-over slope.
The achieved impedance is as follows:
85 ohms@1K , 28 ohms@3K , 17 ohms@5K , 6 ohms@10K , 8 ohms@15K and 5 ohms@20K.
Unless you have a Spectrum Analyzer with microphone, you will need to pick 'Phase Orientation' by ear. It is usually pretty obvious when you get it right.
If the output sounds too loud, simply insert a series .33 or .27uF capacitor in series with one of the piezo terminals. The lower the value the lower the output.
Rather than cutting holes in boxes, I built this project directly onto nice 'baby slabs' of hardwood with felt feet, to place on top of existing speaker boxes.
THE SOUND > Very revealing. Depending on your speakers and ears, this can be like lifting a veil off your sound system, especially with natural sounds.
PS. Don't let that 5 watt transformer rating worry/trick you. It is a 'nominal' value tested @ 400Hz, which does not apply here. Transformers are far more efficient at
high frequencies.

Hello. I've changed successfully some laser diodes in KSS-272A, KSS-271A, old OPH32 or similars, VWY061 Pioneer and etc...
I wanted to do the same with some KSS-151A, but all I have are working correctly, and is a nonsense to do experiments in good working laser devices. In the last month I bought a faulty Sony CDP-337ESD complete, faulty but in good condition. The laser was exausted, 0.5V RF signal and 116mA, the power out is noted in my notes, I don't remember. This is was the perfect candidate.
The KSS-190A and the KSS-151A are electrically equals. The extension cable I build is useful for both.
For to replace and adjust the KSS-190A I used the Denon DCD1500II, which uses the KSS-190A. Is a broken cd that works, and is useful for to experiment.
First, I build the cable extensor. But there was a problem, the amplifier I built for the KSS-272a and other lasers pickup was not very apropiate. I saw that the perfect amplifier was a I-V amplifer. Well, I constructed it with tiny modifications, and it worked.
Then, dismantle the KSS-190A, I replaced the laser diode and assembled another time.
Well, like other times with this things, the first time was with bad signal, and is normal, the device was totally dismantled and now must be adjusted.
Now is working with 1.2V and very clean signal, but must be realigned, the adjuste performed is the most principal.

This procedure is applicable for the KSS-151A. The perform of changing the laser diode should be more easy in the KSS-151A.

If you see the two black filter capacitors, this cd looks like it were used a lot.

There is another curious thing. This cd uses the infamius Elna Duorex II capacitors, however in this cd all are in good state, in spite this cd is older than in the models that these Duorex produces problems, like in the CDP-X33ES.

I've seen that the 7805 regulator have been changed, by a Texas Instruments 7805, and the relays too.

Some pics, some videos, etc...

Sony KSS 190A with new laser diode with adjusting waves - YouTube


Sony CDP 337esd KSS 190A with new laser diode - YouTube

KSS-190A replace diode and KSS-151A measurements - Google Photos

Project page on Github

A simple, high-quality DIY microphone pre-amplifier with switched gain.

The background for this project was that I needed a simple but good microphone preamp for doing acoustic measurements. I needed a switched gain to be able to reproduce the gain setting in a more predictable way than what is possible with a potmeter. I could not find any existing DIY designs, so I decided to make one.

The design is based on the excellent THAT1510 preamp IC. It is also compatible with SSM2019 or INA217. I have followed all THAT's datasheets and app-notes to implement a robust, best-practice design.

A goal was to use simple through-hole parts that I and other DIYers usually have in our parts drawer. So there are no additional IC's or voltage regulators for example, it just uses simple transistors, capacitors and zener diodes for supply filtering and regulation. I selected affordable switches and connectors to keep cost down. Many parts can be substituted without sacrificing performance.

This is an open-source project released under CC-BY-SA-4.0 license. It basically means you can use it as you want as long as you share modifications under the same license, and attribute back to this project. See LICENSE.txt for details.

Specifications
-----

• Microphone preamplifier with switched gain and 48V phantom power.
• XLR input and output connectors.
• Phantom power on/off switch.
• Phase invert switch.
• Gains (dB): 0, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60.
• Gain deviation from nominal: Max +/-0.5dB using E12-series resistors.
• Frequency response: 0/-3dB from 10Hz to 100kHz for all gain settings.
• Impedance balanced output.
• Max output level: 20dBu at 0.1% THD (1kHz).
• THD+N less than 0.005% at 1kHz at 18dBu output level for all gain settings (20-20kHz BW).
• 48V DC power supply required, 30mA max.

* (Will operate with lower voltage DC power supplies with reduced phantom voltage and max output level).
* PCB dimensions 75mm x 120mm, fits the Hammond 1455K120x(1455K1201 - Hammond Mfg.) enclosure.
* Gain switch on top of enclosure for easy access.

Schematic
-----


Desktop version:
-----


Rack version:
-----



Measurements
-----
### Output noise vs gain
20-22kHz BW un-wtd, 150ohm source impedance
| Gain(dB) | Output Noise (dBu) | EIN (dBu) |
| --- | --- | --- |
| 0 | -98.5 | -98.5 |
| 10 | -98.2 | -108.2 |
| 15 | -97.8 | -112.8 |
| 20 | -96.8 | -116.8 |
| 25 | -95.6 | -120.6 |
| 30 | -93.2 | -123.2 |
| 35 | -89.8 | -124.8 |
| 40 | -86.8 | -126.8 |
| 45 | -82.6 | -127.6 |
| 50 | -77.8 | -127.8 |
| 55 | -73.1 | -128.1 |
| 60 | -68.3 | -128.3 |

### Frequency Response


### THD+N vs Frequency


### THD+N vs Amplitude


### Common Mode Rejection Ratio


### Bandpass Noise Level
Note no measureable hum.



---
OJG 2020

Hi everyone,

I'm working on a Scott LK-72-B tube amp and hoping someone can clarify a couple questions about setting the DC balance. The original manual says to remove tube V3 when adjusting the Left Balance then to replace it and remove V103 when adjusting Right Balance. However, I also read this post here at DiyAudio with a good description of setting balance and bias on the LK72B and it doesn't say anything about removing tubes. Then I read this post on AudioKarma that describes the balance/bias process and one of the first steps is "remove the phase inverter tubes (6U8 or others)", which sounds like you remove them all at the same time, rather than one at a time. So I'm not sure whether the 6U8 tubes need to be removed one at a time, all at once, or not at all.

The AudioKarma post also says to attach a 16ohm resistor to the speaker terminals and measure the voltage across the resistor with the meter set to AC Volts, but the DiyAudio link says to attach speakers or resistors to the speaker terminals and measure the voltage "between the plate connections on the two Power tube sockets" with the meter set to DC volts. Is that just two different ways of achieving the same results, one measuring AC and one DC?

I'm going to be replacing the coupling caps and cathode resistors soon and would like to adjust DC Balance and Bias afterwards, so any advice would be much appreciated.

Thanks very much.

I have a pretty basic question...
I'm building a sub with 2 identical drivers that each have 2 ohm DVCs. So in effect I need to drive (4) 2 ohm voice coils. The amp I intend to use has these specs:

• At 8 ohms: 215W RMS x2
• At 4 ohms: 350W RMS x2
• At 2 ohms: 550W RMS x2
• Bridged at 8 ohms: 700W RMS
• Bridged at 4 ohms: 1100W RMS

My question - what configuration will provide the best (highest?) power to drive this cabinet?

looking for Morotola mps-u57 or Central Semiconductor cen-u57

pm me if you got some for sale in reasonable price 🙂

Hi,

I would like to build a simple and cheap tube amp with the schematic below.
There will be one pcb to manage the feedback, but that will come later.
I would like to keep this part of the circuit as simple as possible, on turret or even point-to-point.

Power supply will be one single secondary going to a first 220u 550V common capacitor, then 22 Ohm to 220 Ohm for each channel.
Output transformer screens are supplier through UL connections, LTPI anodes are supplied through KT88 plates using a positive feedback connection to have better sensitivity.
A specific negative feedback circuit will manage distortion and Zout of the amp.

Negative rail will be for bias and for LTPI cathode's CCS.

Transformers are toroidal, and I want to keep them "under the bonnet", with a flat surface on top.
There will be two channels on one single stereo amp.



Thank you for the suggestion.

I am looking for a 24v 6a power adaptor for an amplifier, I saw this Nobsound power adaptor that says its designed for amps and shows its guts. The guts show heatsinks as opposed to strips of metal. I dunno if that would be much better in a sealed enclosure like its in. They are 2 times the price of regular ones. Are they worth it? Anyone have any experience with this? See attached link and see the 3rd and 4th pic in listing.
https://www.amazon.ca/Nobsound-Supp...hvtargid=pla-1118254602954&psc=1&gad_source=1

i have a pair of azure horns AH340, 2" throat full roll over in white. Le Cléac'h 340Hz, 0.8 Hypex
Like brand new, $500 for the pair. Can ship but as they are fairly large, it could be costly.

Hi,

I'm entertaining a pre-amp using RE084 valves and supplying the heaters from a battery, using cathode bias. How would the heather supply affect the operating point? Or am I overthinking this?

I want to use the RE084 at a operating point of ~4V, 4mA, which would need a cathode resistor of ~1k.
Can I simply use two 2k resistors going to ground (one from each side of the heather), this would drain the batteries least as they are from the battery perspective are in parallel with the heather. The alternative would be two smaller ones, from the heater that go to a larger one to ground (for example 2*80 + 1* 960)

Furthermore one side of the heather would in this case be 2V and the other at 6V (the heather are 4V and assuming I have a perfect 4V battery) relative to ground/grid, would this affect the bias point? I could understand that with a higher cathode voltage (relative to grid) such as for a 45 or 300b this becomes more of an issu, but given the grid voltage

Thanks!

Matthew