Hi all,

After the release of the Bigbottle MC only phonostage (thread here: Bigbottle MC only Valve/JFET phonostage Group Buy - diyAudio) i was asked why there was no MM option by a few members. I didn't need MM so i hadn't considered it. Eventually i was approached by Andy who generously offered to redo the PCB design if we wanted to add in MM capabilities. Obviously i wasn't going to turn him down 😀
Alan redesigned the phonostage to offer MM & MC.

A few months has passed and we now have a few prototype PCB's here and rather than release them untested or as a work in progress like i did last time, we thought it would be a good idea to ask for volunteers/guinea pigs who would be willing to construct the phonostage and report back if there is any unexpected results. The idea being that when it is finalised, there will be less updates and a cleaner start to finish build process.

Obviously, you will need to have the ability to troubleshoot the PCB as it is very difficult trying to help people via phone or email. This is a lesson i learned from the first board. I'll do my best to help (I am only a "middle man" after all!) and Alan will too so you dont need to be an absolute expert but a bit of knowledge will be beneficial.

So, we have 3 PCB's available. All i ask is that it's built in the near future and that you report back any findings or measurements that need looking at.

If you are interested, please drop me a PM. Please remember, this is a not-for-profit project so all help is appreciated greatly.

I'll add a few pics of the PCB later today.

Looking at the listed data sheets for D3a by , Philips, Telefunken and Siemens, all give short data for triode operation with grid voltage of +10Vdc. Yet they don't show that area on the curves. Just wondering if anyone knows what the original idea for application was there.

Thanks

Actually all the chipset is on the sockets. Piggy is in very nice condition , collectible and even works. $250. This much becuase PDM100 is over $100 itself. I will post picture when I get home.

I use a pair of fostex pmo.4n speakers on my desk top.

They are individually powered and when I turn them on, they both emit a high pitch tone that slowly disappears as they warm up.

Any idea what’s happening with them?

Hi everyone.
I have a passive home studio system with a pair of older (well maintained) tannoy pbm 8, along with an equally well maintained pair of yamaha ns 10, and i’m trying to find the most appropriate upgrade on the tannoy pair.
Passive, 8’’ woofers, similar frequency response and not far more expensive. And of course i would prefer older used stuff. Not necessarily studio grade. Just different and maybe better than the pbm 8.
Any suggestions?
I guess older yamaha passives 8’’ must be pretty similar to the ns 10 (even if they are one of a kind in a way…).
Dynaudio passives are the first that come to mind. But i guess there are more, maybe cheaper and maybe better.

Thanks.

Here is my latest Tokin SIT amplifier. It is a DEFISIT amp (Depletion Enhancement Follower SIT) output stage based on Nelson's First Watt SIT-5 output stage. Diyers more knowledgeable than me picked apart what information Nelson provided in his SIT-5 owners' manual (https://www.diyaudio.com/community/threads/first-watt-sit5.418023/), and I rode on their coattails and came up with this version.

My build is only the output stage, and it incorporates the duo output capacitor arrangement which can be tweaked to adjust the amount of current amplification that the mosfet part of the DEFISIT push-pull output contributes to the total current amplification. This is a departure from the regular DEFISIT amplifier, where the SIT and mosfet both fully contribute to the total current amplification.

Here are a couple of LTSpice simulations. I did many simulations, but these two are what I based my design on. I chose -47VDC for one sim since I intended to build it using one of my existing amplifier chassis and power supply. I chose the -63VDC for the other since that is a reasonable voltage that will take advantage of the power capability of the THF-51S and still keep the power supply voltage reasonable for capacitor voltage and heat sink heat dissipation.

As shown in the simulation results (47VDC power supply and 2.0A Iq), the measured current through C4 connected to the SIT drain was 361mA peak, the measured current through C7 connected to the mosfet drain was 150mA, for a total of 511mA. As a check the current measured through the speaker, R8, was 509mA - close enough. So the contribution of the mosfet was 150mA/511mA = 29%.

I have not included the LTSpice screen shots of power output but the 8 Ohm power output was nearly 23W at 1% THD and 4 Ohm power output was nearly 40W at 1% THD.


63VDC PS 2A 8R 1Watt:



63VDC PS 2A AC signal current through C4, C7, and 8R Speaker:



47VDC PS 2A 8R 1Watt:



47VDC PS 2A AC signal current through C4, C7, and 8R Speaker:





As mentioned I decided to build the 47VDC version. The chassis and power supply is from my BAF2015 Amplifier - A SIT Mu Follower Revisited With Feedback (https://www.diyaudio.com/community/...t-mu-follower-revisited-with-feedback.408193/). The power supply is CLC, comprising 2x22mF - Hammond 156B - 2x22mF, and an Antek AS-3218 transformer per channel for full dual mono construction.

I put together a PCB design and sent it off to JLCPCB for fabrication. In addition to stuffing the PCB once I received it, I also changed the CLC filter from V+ supply to V- supply.



Initial power-up and subsequent Iq and SIT Vds adjustments went smoothly, and Iq and SIT Vds were stable.

Next up was testing with an 1kHz signal and distortion measurements. Unfortunately when powered up with an AC line powered 1kHz oscillator connected, the amp immediately blew the powerline fuse. So it was trouble shooting time. After checking the schematic and pcb, checking that the input capacitor was not faulty, and not finding any visible ground shorts with the meter, I was baffled.

I knew that the issue was mostly likely a grounding problem and that it only manifested itelf when an input device was connected to the amplifier. Luckily a thought came to me fairly quickly - when I changed the CLC filter from V+ to V- supply, I forgot to move the power supply connection to safety ground on the CLC filter board. The correction was made and success. Only one fuse was permanently damaged.

The dim bulb tester came in handy here as once the fuse blew, the dim bulb tester went in and I was able to probe around with power and not blow anything. In addition to using it during trouble shooting, I always use it for first power-up testing of power supplies during various stages of construction and first power-up testing of audio circuits.

As for the amplifier supply not shorting with no input device connected but shorting with an input device connected, I gave it some thought. The power supply was for V-, with V- from the supply connected as power to the amplifier circuit. V+ from the supply was connected to the amplifier circuit board as ground. The V- from the supply was ground in the previous amplifier but I forgot to change it so it was now incorrectly connected to chassis safety ground. With no input device connected to the amplifier circuit, the power to the amplifier board was floating. Although the V- was also connected to the chassis safety ground and to the powerline/IEC ground, there was no other direct connection to V+, so no short. The live from the powerline/IEC was connected to the transformer primary, which was isolated from the transformer secondary. Also the speaker and input jacks were isolated from the chassis. So with no complete direct connection of V- to V+, the current can only flow through the audio circuit. The chassis was connected to V- but there was no path for the current to flow from the chassis to power supply V+.

When the oscillator was connected to the amplifier input, the circuit was completed, current flowed, and the fuse blew. That was because the oscillator was AC powered and had a safety ground connection. So the oscillator line safety ground connected to the oscillator power supply ground, then connected to the oscillator signal ground, then connected to the amplifier signal ground, then connected to the amplifier V+. The oscillator safety ground is also connected to the amplifier safety ground through the line ground, and the amplifier safety ground is connected to amplifier V-. The net result was amplifier V+ and amplifier V- were connected together - a short circuit. There was a CL60 thermistor at the amplifier power supply ground connection. That would have limited the short circuit current: 47V/10R = 4.7A. Fuse was 2.5A slow blow.

I have swapped power supply polarity before but had always remembered to switch the safety ground connected, until this time.

So always be careful. Electricity can kill.

I am the owner of a pair of Magnepan Tympani 4a’s. At least 35 year old now, and still in great shape. Still I think upgrading the Filters is a good idea. I’m looking for detailed drawings or anything else that can make my choices easier.

I'm coming from playing music, then studying electronics and then sound design.
Along the way I was fortunate to meet an awesome dude who got me into diy audio after i heard his horn speakers.

Got some diy TL's and 3D printed Bill Waslo meh's with 12" bass port cabs. Also a pair of Genelecs 8030.

I'm hoping to upgrade my bass situation in the near future. 🙂

My name is Michael and I have been visiting this forum sometimes before an really enjoyed reading about all your cool projects.

HiFi is my favorite hobby.

Two years ago I startet doing some projects on my own instead of just fixing vintage hifi stuff…mainly from the 70s and 80s.

Right now I am looking for a good solution to drive my vintage Grundig active speakers…I will post about that in the existing thread.

Thanks for letting me take part in this great community!

Greetings

Hello

Looking for good cabinet plans for Markaudio Pluvia 7HD

By googling i did find this one https://frugal-phile.com/boxlib/pensils/PensilP7HD-260520.pdf but its not on offical frugal phile site you can only find it by direct link. is it still ok for PLUVIA7HD.2 GEN ?

Also considering plans from:

https://sites.google.com/view/low-end-diy-loudspeaker/diy-tqwtml-voigt-pipe-with-damp-duct
https://sites.google.com/view/low-end-diy-loudspeaker/diy-tapered-wave-tube-with-damp-duct-twtd

Does anyone know any other plans for Pluvia7HD?

Thanks

The content of this thread is my personal opinion and does not represent performance based on objective metrics.


Information about symphonic-mpd, a CRAFTED LINUX for Raspberry Pi4.

It has been developed to target audiophile who want high quality music playback on I2S output.

Official Forum
symphonic-mpd

If you are interested, please ask your questions in this thread.

In order to use the SD images of this distribution, you need to join the official forum.
If you would like to join, please email me below with your handle name.

symphonic.mpd@gmail.com
kubotayo@jcom.home.ne.jp
mark.create@gmail.com

So, the kit of the AtiRi has been bought and I am thinking of pumping it up and make a Kawero Classic clone (kind of) out of it.
But I need your help regarding the bass segment.
My plan is simple, take the two way AtiRi (15Liter) and put on a 40Liter bass reflex cabinet. untill now same as Kawero.
The woofer I will use for the 40Liter is the 10inch Faitalpro RS350. it will be driven by Hypex Fa501.

Now, I really really want to nail this bass, clean accurate, powerful.
So the following ideas are:
1. 40liter-bass reflex with one RS350 10inch driver
2. 40liter- closed cabinet with one RS350 10 inch driver -infinite baffle
3. 40liter- Closed cabinet with Two!! RS350 10 inch driver

I know its more about opinions and everything is a compromise but it would be great to hear your preferences.

Thanks!

Now it is new plans on Markaudios site.
I dont know were we can buy that driver.
Maybe it will come later.

https://www.markaudio.com/online_shop/11-cm/maop-11ms/

Hi Guys, i have vintage Audiolab 8000a integrated amplifier, and i want to replace its volume POT which can be control remotely
without any compromise in its tonal character and sonic quality. which pot is best for it in term of quality and specification.
best regards

Hi all
I'm trying to design a 3-way speaker based on mid-range and tweeter I already have (used in a 2 way speaker some years ago).
I decided to add SB26SFCL38-8 to these 2 drivers in bass reflex configuration. The volume for the woofer will be around 88L with a resonant frequency is 27Hz.
I want create a cabinet with hard plywood 19mm with external size WxDxH 38x55x63 (the height is a constraint).
The cabinet will have a "small room" for the mid and tweeter of about 8L.
The port tube will have diameter of 9,2 cm and length of 22,5 cm
I have 2 main doubts now (may be more 🙂)
1. Where put the port tube. I have not enough space below the woofer do I would like to place it upper. Something like this...



I also did a try with 2 port of 6,6 cm and 24,5 cm length below the woofer.



What do you think is the best solution?

2. How many braces, where to place them and how shape them. I'm not so expert about this aspect.

I am living in Berlin since 35 years and I am engaged in building speakers privately and professionally since I was 12 years old. Now I want to return to my roots building DIY Transmissionline Speakers. Back in the 70ies I started to build speakers with SEAS drivers, PEERLESS drivers and GOODMANS drivers. But my heart finally fell on KEF drivers and that´s where I want to restart. Let´s see what ideas I get after being involved deeper into the exchange on this forum. Regards, Mark.

I was dissatisfied with modern hifi that just was not hitting the spot for me. Was not enjoying lisetening to music. Started buying a few bits of vintage and the magic was there again and these things are so lovely. Cant stop listening to music now.

Nothing particularly high end. A few low power Sansui, 555, 101, 555a 2200, 217II and 317. Got a Sugden A48 MkII and a Naim Nait 1. Got a few different speakers. Spendor BC1, Ditton 44, Linn Kan Mk1, Lin Sara and Meridian M20. Also ended up with a Sondek LP12 that needs some TLC.

I am not experienced with electronics but really interested now and learning by doing. One of my Meridian M20s is not working. I am trying to fix it. I am getting pretty close to working out the issue though. Identified the op amp that is failing. Not worked out why yet. When trying to google for a service manual for these there were a couple of posts on this site asking for the same and that is what brought me here. Looking forward to going on the journey learning about fixing, maintaining and even improving all of this lovely old gear.

For sale a pair of ATC SB75-314S in very good condition and with fresh new surrounds.
They can be used as well to replace the SB75-314SL because they behave and measure equal to those. Just Some better an more linear roll off in the SL. The SL has not a resonance peak more than 12dB below crossover point at 500/600Hz.


Price for the pair will be 450€ + PP fees + Shipping at cost.

I have a pair of new and unused Scan Speak tweeters D2904/98000 for sale from a project which has been cancelled.
The tweeters are paired and packed in the original box.
Price: 250 euro plus shipping (EU only).
Send a PM if interested!

Stock clean up: a pair of unused Audax Aerogel dual voice coil 17 cm bass/mid drivers (type HM170Z2)
Bought for a project which was never started (due to other priorities).
The units are packed in the original box and are not broken in.
Price: 170 euro plus shipping (preferably within EU)

I have an old Krell MD-2 CD turntable, and (among other issues) several segments have gone out on the LED display. After looking around online, I found one person in France that had built a replacement, but details were kind of scarce, so tried to reverse engineer my display module based upon the tidbits of information that I was able to uncover.

After hooking it up to a scope, it appeared to use SPI (keep in mind that I'm not very smart), but I just got rubbish when I created a small Arduino program to read the data, so I traipsed through the available LED drivers on DigiKey, and came across the MM5450 as one of the very few chips that didn't require I2C. Upon reviewing the data stream again, it appeared to fit with what was required to drive this chip. Anyway, I did the best that I could to guess the pinout of my existing display board (it uses an unmarked glob to hold down the IC die), and was able to reconcile it with the MM5450 pinout, so I made up a board, bought some parts, and tried it out. It appears to be fully functional, so I thought that I would share it here so that others can create a replacement for themselves as necessary. I'm kind of hoping that since this hardware is over 25 years old (and apparently out of production for quite some time) that Philips won't mind too much the publishing of plans for a replacement...

Anyway, here goes with the information:

Feel free to use this information however you wish, so long as you don't make anyone pay for it. I don't care if you charge someone to assemble a board for them or something (it's none of my business), but the information should be kept in the open. I abhor GPL-like licensing, but I do expect you to not be a turd.

I am just a hobbyist (and a really unintelligent one at that), so I do not make any representation that information is accurate, safe, or suitable for any purpose, even a purpose that may be implied by the information. In other words, I did the best that I could, it worked for me, but it's not on me if you hurt yourself or start a fire or something.

I have the board shared at OSH Park (https://oshpark.com/shared_projects/P3nC9ISV) for convenience. I make nothing from this link or design (AFIAK), and I don't care from where you order your board.

BOM:

• U1 - Micrel MM5450 (PLCC-44) LED Display Driver
• DS1-DS4 - Kingbright ACSA03-41SGWA-F01 7-Segment Common-Anode LED Display (Green, other colors probably available)
• D1-D2 - 0603 SMD LED (Green for use with the specified green LED digits)
• R1 - 7.5kOhm (or higher) 1206 SMD Resistor (controls brightness)
• C1 - 1000pF 1206 SMD Capacitor
• J1-J3 - 0.1" header system of your choice

Electrical Schematic:
View attachment NSM4202A Schematic.pdf

Front of PCB:


Back of PCB:


Gerbers for PCB:
View attachment NSM4202A.zip

DipTrace Schematic and Board Files:
View attachment NSM4202A DipTrace Files.zip

(I posted this on the AK forum, and so far nobody can give me a good answer, so a gold star to the one who can . . .)

So I'm thinking for my next tube amp build I would really like to do a little integrated 6AQ5 push-pull, so I was researching some of the greats, and apparently the Voice of Music 1404 integrated amplifier (581 console) really stands out as a super performer based upon many comments I have read.

I have a one page schematic, as well as a pdf copy of the SAMs posted below for the model 581 console, which used essentially the same chassis. It very clearly shows that the left and right output transformers are different- one has a primary impedance of 5700 ohms, the other is 7000 ohms. This is confirmed in the schematic, which indicates a different DCR for each primary (325 vs 340 ohms per side). These are not two "alternates" or an accident, this is a deliberate design choice to use a different load line (but same operating point) for left versus right.

Does anyone know why this would be done? I have never seen that before.




BTW I think the super cheap 6AQ5 (essentially a 6V6 in a 7-pin peanut) will be very fun to play with- guitar amps are using them like crazy but still seem to be quite overlooked in new audio builds.

I am considering how to improve my system for a modest cost. At present, I have no preamplifier. (I am using and amplifier with a volume control). A possible cost-effective solution might be the gremlin headphone amplifier. The problem I am attempting to overcome is the fact that the gremlin uses strictly balanced input and output. All my components use unbalanced cables.
I at present I'm unable to discern exactly what is needed to convert an unbalanced input into the gremlin and output an unbalanced output from the gremlin to the amplifier.
Would the following cable work for input:
https://www.amazon.com/TISINO-Stere...l+rca+to+male+xlr+cable&qid=1746337003&sr=8-3

Would the following cable work for output to the amplifier:
https://www.amazon.com/gotor-pin-Ma...+to+male+xlr+cable+4+connector,aps,184&sr=8-3

Thanks in advance for any comments.

I've been learning Hornresp recently and was interested in designing a BVR for a pair of MA CHN 110's. I'm reasonably new to speaker modelling so would welcome feedback. I think what I've done so far seems reasonable in theory but I'm sure there are some variables I haven't accounted for.

I'm undecided if I will build this as yet - I'm enjoying the driver (in a Pensil) and would be curious to hear other configurations. Especially something that may add a little more 'punch' in the mid-bass.

I've also attached a quick drawing from fusion, the dimensions are no longer correct as I've changed the model since, but wondered if this basic layout for construction might work?

Matt

Hi All,
I'd like to gauge interest in a Group Buy of PCBs for passive crossovers for speakers. I've made some for my own use and am happy with the outcome. I've attached some pics of one that I made. I can post more as I have 4 made so far. I am considering laying out generic type PCBs for 2-way and 3-way crossovers. The PCBs I got were from JLPCB which were incredibly inexpensive. With the current tariff climate, the shipping has gone up considerably because Hong Kong is no long shipping packages but even so, prices for the PCBs would be pretty cheap. Feel free to post so I can get an idea of level of interest and I'll take it from there.

Light fantastic​

“The P1 power amplifier requires a super clean high current power supply to turn the low voltage line level music signal into hundreds of watts of output power. To do this, Siltech designed the Apollo Light Drive. A super-strong AC-powered light source is used to drive a photo-electric cell, giving a totally noise-free, galvanically isolated DC output. This then drives the amplifier’s output stage, keeping it absolutely immune from mains-born distortion. The idea behind this is not new, but its execution in a high powered amplifier is extremely challenging. The result is ultra-clean, low distortion power – and lots of it.”

Has anyone tried DIYing this concept?



https://www.siltechcables.com/saga-amplifier-system/

I am a maker and a tinker. At the school where I work, I also maintain a makerspace. Since I was 12 years old, I have been creating all kinds of electronics, from mixing consoles and amplifiers to microcontroller-controlled devices. Recently, I have been working with Arduinos, micro:bits, and Raspberry Pis. I teach kids how to program Lego robots. Additionally, I educate young people on 3D design and printing. At school, I also teach CNC programming and manufacturing, as well as 3D design and CAM. At home, I have my own lab where I always need some new gadgets. 😊

Does anyone have a simple schematic using just CE, CC which can output 15W @ 4 Ω load with efficiency >40% and the input resistance higher than 20k using ± 12V.
Thank you very much.

So I just repaired this JL 600/1v3, PS blew, took out FET, gates, and half the OP.

I replaced PS FETs with 3205@10Ω gates, and replaced the OP FETs with IRF540. PS gate wave seems to build slow, but could be a feature of JL boot process, but I’m getting crazy feedback on startup and shutdown, DC offset on each process gets into the single digit volts, I’ve tried cleaning the Pots/switches as well. There is 2 Pots near OutPut area, but I don’t know what they are for and I’ve never had to mess with them before, I’ve never had a problem with DC offset on JL amps before. Is that what this is or something deeper?

Video link below.

Login to view embedded media

Im building a center channel and have some measurments questions. The drivers im using are:
Tweeter: HiVi RT1.3WE
Mid: 5" SB 13PFCR25-8
Woofers: (2x) 8" Silverflute W20RC38-04

Target crossover points are:
300mhz/3000mhz. (80Htz crossover to sub)

Tools im using:
Dats V3
UMM6 usb mike
REW
Xsim

Question:
When making the FRD and ZMA files for the two woofers do i measure them indiviualy or wired in parallel like they will be used?
If measured together are they still represented in xSim with one driver?

-Travis

Hello, I'm currently trying to repair a Luxman L-3 that I bought at a thrift store to make it mine and enjoy! For now I've read all the previous posts made on this forum and though I found the issue when I changed a resistor that was problematic for someone else (mine also was bad). Replaced the resistor with one that was good (Amazon) and tried to turn it back on... ohoh the dim light tester stays on.

That was my initial try at repairing it, since then, I tried to find the short, but I can't seem to find anything promising. I used a thermal camera to identify hot spots on the power board and found to spots, one around the D403 and D404 diodes and the Q408a area. Since then I pulled all the components to test them outside the circuit, but they all seem to be good from my understanding.

I'm kinda lost and don't know what I could check before starting to resolder all the components back on the board, do you guys have any wisdom to share that could help me with my project! Thanks. There seems to be a good amount of info on this site about the amplifier so if you want something specific let me know and I'll share it with you (schematic, components list, voltage drop of the components I pulled, etc.).

Hello everyone, I'm Jimmy from Italy, I'm an audio enthusiast but not a very skilled (technically) one, I know here I can find very prepared people. I also hope I'll be able to contribute to the community!

Thanks in advance for any help!
Ciao!!

I bought these drivers back in end August I think it was, and I've finally got a box for 'em. I've measured up the in box response and played around with the results in XSIM. I still have to order XO parts, and do a final sand and finish on the boxes. But I thought I'd share where I'm at.

I kicked out a thread to discuss the drivers when I ordered them, it's https://www.diyaudio.com/community/threads/tymphany-aula02014-0006-pe-buyout.416365/

Woofer (buyout, NLA) is this 8" tymphany pro audio with a big honker magnet
https://www.parts-express.com/Tymph...-Paper-Cone-Woofer-8-Ohms-299-2265?quantity=1
I got 'em for $17 each!

Compression driver is Celestion CDX1-1446
https://www.parts-express.com/Celes...-Compression-Driver-8-Ohm-299-2257?quantity=1
This one is also a buyout but I think the same driver is available regular production.
I've got it on this JBL Selenium HM17-25 https://www.parts-express.com/Selen...al-Horn-60x40-1-3-8-18-TPI-264-308?quantity=1

I have modeled it up in 30 L and ported at 60 Hz. Software wanted to suggest smaller / higher, but I'm trying to get this thing to dig down far enough to cross to my sub. I have 3D printed a port according to geometry in this Harmon paper about optimizing ports. https://www.diyaudio.com/community/attachments/harman-port-study-pdf.893225/

I was trying to conceptualize how I'd put this speaker together, and I thought of trying to time-align the drivers, so I measured the acoustic offsets. The horn+tweeter came out 70mm behind the driver (mounting features in the same plane), which was more than I was expecting. I had a little thread to consider options about that https://www.diyaudio.com/community/...nique-for-horn-out-front.419357/#post-7851615 eventually I remembered that @xrk971 has a crossover topology that wants the tweeter a fair bit delayed WRT the woofer, and that's the Harsch XO, he's got a thread about it here - https://www.diyaudio.com/community/threads/s-harsch-xo.277691/. I was considering a 2kHz XO, and the delay according to the Harsch thing was 85mm, so another sheet of plywood for the woofer to sit on was just about right.

So that's about how I dreamed this one up! Here's how it looks...


Ah... every thread is better with pictures. I've got roundover I think it's 1" on the vertical corners. Boxes made of arauco ply 3/4" from Home Depot, I'm still trying to decide how I'm gonna finish them. I like the lines from the ply on front.

Ground plane, on-axis (spkr tilted down to point at the mic) 2m distance acoustic measurements look like this


THD is good on the woofer, and FR is fine to 3k, but I think that is a low baffle step from 100 to 500? Speaker is 12.5" wide. Anyway that shift ended up being around the upper of the two impedance peaks in low woofer response, that made it kinda tricky to correct passively. FR on the tweeter seems pretty nice, but measurement looks like kinda high 2nd order HD.

I've been fiddling with the XO sim to get something I like.... here's where I'm at.



Initial idea was to have the cross at 2k, but in the course if trying to make it work I have floated up from there. So I think my offset is actually a little too much, and my phase peak is a bit larger than it might have been.

If you go for this sort of XO, it is (quoted from XRK's thread)...

1. Set the low pass filter for the woofer as a 4th order Butterworth at central frequency, fc for the XO centerpoint.
2. Set the high pass filter for the tweeter as a 2nd order Bessel at fc.
3. Set the delay of the tweeter equal to 1/2 of the period of one cycle at fc.
4. Use all positive phase on woofer and tweeter.

Here's what I've learned: 2nd order -acoustic- roll off is pretty slow! 2nd order electrical is normally fine, but when you are looking at the acoustic rolloff that happens naturally that doesn't leave much space to put in electrical protection. So I ended up at higher F than I was initially targeting. It looks like 2nd order electrical on the CD but it's pretty low Q, that inductor is only helping out at lower frequencies. Impedance compensation on the CD can help you get the shape theory wants.

I think I've attached the XSIM file in case anyone wants to play along.

I'm looking forward to hearing these, but I haven't pulled the trigger on XO parts yet. Every time I buy parts a couple days later I'm like "you know what I SHOULDA done...?" so I'm still meditating on it.

What do you think?

- Adam

I would like to add a headphone output to my Tubelab SSE amp suitable to run Sennheiser HD598. Has anyone done this? Does anyone have a circuit they are willing to share or a pre-built board that would work with the SSE?

Just a heads-up...

This month's (UK) Elektor (April 2012, dropped on the mat this morning...) has a long article by Doug Self with, what he says is, his first published new pre-amp design since 1996. Side notes on Peter Baxandall, references to "Baxandall and Self on Audio Power" - all sorts of stuff. Pt. 1 is about design methodology and his pet subjects of sources of noise & distortion - does include the schematic though.

Kind of fun... (if you are a Self-devotee)

Specifications
Test conditions: supply voltage ±17.6 V; all measurements symmetrical; tone control defeat disabled.
Test equipment: Audio Precision Two Cascade Plus 2722 Dual Domain (@Elektor Labs)
THD+N (200 mV in, 1 V out) 0.0015% (1 kHz, B = 22 Hz – 22 kHz)
0.0028% (20 kHz, B = 22 Hz – 80 kHz)
THD+N (2 V in, 1 V out) 0.0003% (1 kHz, B = 22 Hz – 22 kHz)
0.0009% (20 kHz, B = 22 Hz – 80 kHz)
S/N (200 mV in) 96 dB (B = 22 Hz – 22 kHz)
98.7 dBA
Bandwidth 0.2 Hz – 300 kHz
Max. output voltage (200 mV in) 1.3 V
Balance +3.6 dB to –6.3 dB
Tone control ±8 dB (100 Hz)
±8.5 dB (10 kHz)
Crosstalk R to L –98 dB (1 kHz)
–74 dB (20 kHz)
L to R –102 dB (1 kHz)
–80 dB (20 kHz)

I would like to build this amp and I need the power supply ( about 100v 200ma on the v-fet but a bit higher because the Output transformer primary impedance ) to be particularly silent since it is connected to a compression driver with 113db of sensitivity. I was thinking of using a CLCLC power supply (to have few mV of ripple) and I was wondering if the use of a Saligny power (HVHF in this case) could be useful.
My problem is that at most I can use PSUD II and therefore I have no idea how to model a power supply with a Saligny bridge. Any suggestions?

what do you guys think of this phono preamp ? i know nothing really - dont even know if its in this diagram?

Trying to find out what size this resistor is in my unit. I am having trouble figuring the color code on this resistor it is in a Sonographe SC25. My unit was modded and I am going back to original, but this resistor and the cap next to it were removed and would like to replace but do not know size on both. Thanks for any and all help in advance.

Blaupunkt P652c 6 1/2 two way. Pair NIB $50.00

4" Coated Paper Mid/Woffer P/N 55-1200 8 ohm/40W. Used pair $40.00

3" Paper Tweeter Bukooo DO7776/2M24 8 ohm 40W Used pair $20.00

1" Mylar Dome Tweeter P/PN11028-584560 New $25.00

All OBO, Paypal plus shipping.

Hey guys I was wondering if someone could draw up this crossover for me - much appreciated! I would like to do some mods to the crossover to tame the tweeter a bit.
Thanks in advance.

I have been playing around with designs for a small, thin kitchen system for a while now. I have a few drivers and layouts in mind and I would like everyone's opinion. If there is a large objective difference between these I would love if you'd point them out.

Here is the frequency range I would like to use the midbass units in. The green line.

Shotting for an F3 of 38-48hz. We like bass in our house.


Here is a mockup of the design in its location. This location and temporary until we get a new house. Then it will live in the new kitchen. In the new kitchen it will be far more separated. We will not get into the design details of the rest of the system here. Just focus on midbass drivers. I'll make a thread for this build once I get a more concrete idea of what I'm doing.

The narrow baffle is key since they cannot take up a ton of counter space and I want a nice spread of sound. Probably going to be 5-7" dual woofer, 3-4" mid, 3/4" tweeter. Nice spread of sound.



Box size will be between 24-50 liters. Quite a spread I know but I could easily make it taller in a MTMWW layout or not as deep to go lower in volume.


I really want to try out dual woofers here. Originally I wanted to use these Dayton 7" drivers and I still might. I feel these are more woofer than midbass though. They are cheap. They have some decent reviews. I can get them for $45 on amazon even though they are out of stock at PE. I would dual these. These are modeled in the mockup above. Aluminum, easy to clean

Next up are these currently unobtanium Peerless 5.25" SLS. I have the 8" SLS and I love them. These are 4 ohm so we are looking at series alignment. They are low sensitivity so definitely 2 of them. They would work very well ported and I could get away with a smaller and narrower enclosure. $35 a pop when PE has them, which should be soon. Poly, easy to clean.


Another unobtanium. I always wanted a set of these. Should be available soon. Are these more of large mids than they are woofers? I like the fancy motor design, they have incredible reviews. I could use one or two of them. Two would be best with a passive radiator. This, of course, is more expensive than the last two options. $90 each and another $50 for a PR. Paper, hard to clean, maybe not best for the kitchen.


I feel these are interesting driver. I know little about Wavecor. They look cheap, they seem overpriced, they apparently measure just as well as scanspeak drivers, they model well, and the distortion graphs have very low distortion right where I want to use these. Cannot validate but read multiple times that the balanced drive is the same technology used in the revelator lineup. Same price as the NE180W. Not as cool looking but if it has better dynamics I am all over it. Would need two. Could also use the 6.5". Paper, but looks super smooth so maybe easy to clean?


Definitely need two of these in series. Not sure if these can match the lower dynamics of the other choices. They sim out well enough for the bass I want. Are these more of mid range units? Aluminum, easy to clean. Pretty pricey for a 5" at $80 a pop


Pushing the limits of the baffle allotted baffle dimensions we have this Satori unit. The 6" is unavailable. Price point dictates I only use one. Defeats my purpose of trying out multiple woofers. By far the most expensive at nearly $200. Especially for a system that will not get listened to for hours like our other systems. I hear it is only slightly better than the aforementioned Peerless with the similar motor design. Which is a rip off of which?


There are a handful of Dayton drivers like the reference series I have also looked at but none of them stand out in any way as far as measurements, price, or reviews. I see no one ever mentioning them as notably special drivers like this collection I have assembled here. If nothing else, I surely do my research.

Let me know if I should be looking at some other driver. Again, midbass dynamic and an F3 of at least 48hz is the goal here. 25-50 liters.

Need help hooking up the main speaker system's remote.
rggl front rggl
rggl back rggl
Caution: floating grounds do not use with common ground system /What does this mean for me, hooking up four speakers?

Next is the main in /pre out front
back main in /pre out

2ch a,b both/4ch a,b and both
How to get them all to play on at once a b and a+b

tape 1___tape2
front and back
play and record
been working on this for weeks, think I got it, then I don't like the way it works, also some speakers don't work on a , b or both some speakers on sometimes, and then on with all
still have to find out how to hook up equalizer and subwoofer if I can to this old Planar XR4120 FOUR/2-channel BRIDGED RECEIVER????
I DO NOT KNOW HOW TO TRANSFER FROM ANDROID CELL TO THIS CHROMEBOOK SO NO PHOTOS UNLESS I CAN SEND TO MAIL OR SOMETHING

Hi all, newbie here.
Interests are tube and vintage SS audio and music gear.
Enjoy HH Scott, Dynaco, Fisher etc on the home audio end.
On the guitar end, I like everything that is point to point or tag board wiring, PC boards not as much.
Really get a big kick out of converting vintage tube PA amps for guitar use.
I build guitar effects for giggles too…
Located in northern Illinois

Hi everyone,
I'm a fairly new (second) owner of an MF nuVista m3 amp and was thinking of doing a service on it: a) replacing the old Jamicon electrolytics and, if at all possible, removing any electrolytic caps from coupling duties; b) checking/setting/re-setting the quiescent current on the channels.

With regard to a) there is one 10uF/63V cap that I just can't find a good-sized film cap to replace it C1 and C101 on the attached diagram (Nuvista_M3_Pre-amp_Line_OP[1].pdf). The other coupling caps in the chain (C32, C40, C41 on the right channel) are already some type of film cap, yellow-coloured with a circled L logo--not sure how their quality is honestly--although I'm going to replace them with WIMA MKP10s anyways. Not all that pricey and I'll have it all apart anyways...thank goodness for suppliers like mouser and digikey etc.

Second item, b), does anyone know how "far" I should set quiescent current, i.e. bias into Class A operation? The SAP15's datasheets indicate 40mA, (so 8.8mV across pin 4,5 or 1,2 depending on N or P type), but some manufacturers seem to like "giving it a bit more." Anyone have any thoughts/experience with MF quiescent currents?

Thanks!
verkion
P.S. Attached the whole bunch of M3 Amp diagrams for people's reference. I'll be replacing PSU caps too as those are the ones that are looking "slightly fatigued." i.e. plastic cover is puckering although the metal under it feels fine...for now.

Copyrighted materials removed by moderation.

I'm excited to join the DIYAudio community! I've been on an intense journey into high-end audio over the past year—diving deep into summit-fi gear like the Mola Mola Tambaqui, Feliks Audio Envy, and RAAL Immanis. I listen primarily through vinyl on a Pro-Ject Debut Carbon EVO, and my digital chain includes components like the WiiM Ultra and RME ADI-2 Pro. My musical tastes range from Pink Floyd and Fleetwood Mac to HVOB, and I'm always chasing that next level of sonic realism.


I joined DIYAudio to connect with others who are passionate about sound, learn more about tweaking gear for peak performance, and maybe even try some DIY builds down the road. Looking forward to exploring and exchanging ideas with all of you!


Cheers

Thank you so much for allowing me to be on this great forum! I've been an electronics technician for several years and also a musician.

I've recently put music aside to focus again on studying electronics and dedicate myself fully to my small lab!

I've always worked with audio repair, but now I'm focusing more on all types of professional and musical audio equipment, as well as some vintage ones.

Greetings and thanks again!

My Toshiba XR-Z70 CD player lost the right channel and it turns out the DAC chip is faulty.
If anyone has it (yes it's a long shot because it's very old), I'd be happy to buy it.

Should have thought of this before. I am looking to buy a Carver Sonic Hologram to rebuild. Got someone who is interested and so I figured that I could start looking around for an old unit, working or not.

I had problems with my email so re-registered under a different name and email address. I used to be known as John Jones and joined back in 2003 I think. I am mainly interested in TDA1541A dac designs.

Hello,

Long time...🤓

I’ve built a few Lowther back loaded horns over the years... I am now looking for a design that will suit my A55 drivers. I was looking at the Alerion plans, but it would require substantial mods to fit the fat A55 magnet in there. I was wondering if anyone here has experience building a BACK loaded horn for this specific model (or the A45)?

Any help woud be appreciated.

Thanks.
Dan

Hello. Repairing and restoring old audio equipment is my main hobby. I check diyaudio mostly for adcom information. My latest project is a Adcom GFA5800 arc welder that i am trying to convert back into an audio amplifier.

Hello Swap-Meet Community,


Many years ago I designed and built my own passive crossover pairing a RAAL ribbon tweeter with Scanspeak drivers (see my old thread: https://www.diyaudio.com/community/threads/passive-crossover-for-raal-and-scan-speak.227199/). Life intervened —but now I’m ready to dive back in and I’m looking to source the following parts or kits:

1. RAAL ribbon tweeter
   – Any SR1a / 140-15D models (new or gently used)
2. Scanspeak top-of-range drivers
   – Beryllium-dome tweeters (e.g. Illuminator series)
   – Revelator midranges / woofers
3. Accuton ceramic drivers
   – C-series tweeters or high-end ceramic woofers
4. Passive crossover boards or component kits
   – Specifically configured for RAAL + Scanspeak or RAAL + Accuton combinations
5. DIY crossover parts
   – Toroids, air-core inductors, film capacitors, resistors, PCBs—ideally matched to the above drivers

If you have any of the above sitting on your shelf, please PM me or if you have full speakers that would be nice too.

I'd like a big clunky low distortion/ reasonably high spl capable 2.1 boombox centered around my GRS 12PT. A 30 liter 3rd order closed box would do the "point one". I'm looking (if sufficient money comes) at the 16 ohm Eminence Alphalite 6B to reach to 200Hz (again probably cap assisted) plus a tweeter. I know it will be stupid large - perhaps "stupid" period but am having health issues and want to be entertained, It would be run by a $40 Kinter 3118 2.1 amp and a phone. The Kinter has good SQ but its tone controls offer no boost.

A more practical solution due to such close channel spacing with 2.1 in one cabinet would build a MONO boombox.

Here's "1 watt" 2pi for 30 liter with 325uF









Alphalite 6B is a 16 ohm driver - helpful to get closer to the woofer's sensitivty. Kinter's "sub" channel says 180Hz lowpass (might be 6dB/oct ?) plus 6B weighs only 1kg. Here's 1.5 liter with a cap.

So with these drivers I'm up to needing 33 liters air-space.

Some sort of tweeter is needed























.

Hi all,
I got two of these kits off ebay http://www.ebay.com

It all came very well packaged, and everything was there, except for a cap, which was the wrong value (220/63v instead of 150/80v). No big deal, i changed them all to 220/80v just for the heck of it. The PCBs look very robust and very well made, they're thick and heavy, almost glass like! They are, alone, totally worth the money. The output transistors (KEC D1047/B817) don't inspire a lot of confidence, but they should be ok for domestic music.

I assembled the kits and hooked them up to a 33v-0-33v beefy power supply for some testing. Both kits seem to work ok, and they sound just fine. I tried a 4Ω/100w sub woofer, and it quickly reached it's xmax. The heatsinks got warm after 2 minutes, but not hot...

Now the problem is, despite the good sound, i can measure no bias current at the outputs. The heatsinks are cold as beer even after an hour of being turned on with no signal at the input. I used 10Ω power resistors at each rail, and i calculated an idle current of about 13-14mA per rail, per amp module. It seems very low😕.

With inputs shorted, the emitter resistors (0.15Ω) all measure dead zero mV (0.0). The voltage across R26(200Ω) is about 850mV. I think thats about half the optimal voltage to even begin conduction at the output transistors.

What baffles me, is that the amp sounds just right with no apparent output bias. Even the top end sounds smooth, no signs of being grainy or harsh at all. Is that normal?

Could it be that the rail voltage is rather low? The optimal voltage per rail, according to the designer, is around 65v. I will test again with the power supply which i intend to use permanently (57v rails). I hope the higher dc voltage will affect the, almost non existing, standing current.

Here is a (not very revealing) schematic i lifted from another thread. I haven't checked for errors, but it seems close enough.

I have a pair of brand new in the box B&C DCX50 2" coax horn drivers for sale. Boxes were only opened to inspect them, otherwise brand new. Need to free up some space for new projects. Price is $850 shipped to lower 48 US states

I remember a few years back there was a guy here (big un) who had the audio nirvana 15" full range speakers and thought really highly of them - I'm wondering if they are still in use, and if so, are they still as good? Or has time revealed any short commings...?

I am starting this thread to discuss the construction phase of building an Shigaclone MKII Black CD player / Transport .
I will post photo of building and some modding I will do on this board.

I'm looking for advice on a mono speaker design for a small room.

A couple of years ago I had an idea of building a big Tractrix front loaded horn (FLH) and large mid-bass horn to go with - for a single mono speaker, i.e. a large 2-way (at the time inspired by Tune Audio). The mids driver used by Tune Audio is a modified Fostex 126 but I decided for some reason now lost in the mist of time to buy a Lowther A45 driver. I didn't proceed very far with this idea once I realized that I don't have a large enough room for such a beast and that the work effort involved was just too much for me to take on when I have other demands on my time. So I have this Lowther A45 just sitting around and I'm not sure what is the best way to put it to use. I'm interested in some suggestions from the forum members ?

To keep this simple I'm OK accepting some compromises in terms of the performance in order to limit the size and complexity so that I can build something without it taking months of effort. I'd also like to be able to deploy the speaker in a smaller room where it can provide a more intimate listening experience, partnered up with a tube amplifier.

1/ The driver is not really suitable for baffle mounted use due to the rising treble response (see attached datasheet). So, right off the bat I expect I'll need to address that limitation. One option is to shape the frequency response of the driving signal, either a filter network at the driver, or at line-level. The other option is to shape it physically by employing a small front horn, something designed to help flatten the frequency response rather than provide directional control - I'd actually like wide dispersion if possible.

2/ The driver is not really suitable for generating bass, it's got limited cone area and limited x-max. I guess it's good down to 200Hz to 300Hz at moderate listening levels suitable for a small room. Other than accepting limited low frequency output the only option would be to add a supporting woofer.

So with my limited experience I have been thinking about
a) Open Baffle with small front-horn on the Lowther and with the woofer needing real power it would have to be a bi-amp set-up,
b) A modest compound horn, i.e. a back loaded horn (e.g. Lowther Alerion for which I do have the plans) perhaps with a small front-horn on the Lowther. A separate sub is possible. What about a double mouthed horn - worth the extra wood ?

So as you can see, I've given this some thought already but I've so little experience of these things.

Your thoughts ?

USSA-5 build and review:

Amplifier Design/layout: Fab (The Great and Powerful Ape)

Amplifer PCB Layout: Alex

PSU Design/Layout: Project16

PSU PCB Production: Prasi


I couldn't stop thinking about this amplifier. The obsession began with a few fleeting traces of it's existence. The few members that have actually completed it were mostly silenced by its greatness. When I had enquired about it, people simply said "Oh, the USSA-5? It's the best amp I've ever heard."

I had to build it. But, the great mind that designed the amp wasn't going to just give me the boards. I offered to build a children's wing at his nearest hospital in his name. He said no. I said I would make huge donations to wildlife preserves around the world. He still said no. He was like talking to Willy Wonka and I was Charlie Bucket. I needed a golden ticket....

In the end, what worked was honesty and a promise to do two things: to build the amplifier and write a review.

So, here it is.

Last of my DIY parts

Bundle of Soekris two R2R DAC boards with many kits and accessories
this bundle includes:
1 - Soekris DAM 1021-02
This is new and tested confirmed working 100%. comes in original box from soekris with molex connectors, the USB cable to pragram the firmware and Neutrik XLR connectors are new and perfect. these are the pictures: Login to view embedded media
2 - Soekris DAM 1021-01
this is the one that is installed in the box. i have used this for coax and usb input a lot and sounded glorious. pictures below

3 - AMANERO USB ITS INSTALLED IN THE BOX,. pictures below

4 - AZ OLED lite Green color
this is perfect and tested. it is installed in the box. picrues below.

5 - Normundss kit for soekris 1021
here are the pictures:


6- the aluminum box with vu meters. this is an awesome box and i prefer to keeep it. it is complete and i have all parts and will be included

Things that i still have for sale: Login to view embedded media
1 - the linear power supply has really good and expensive and like new capacitors. the transformer is antek As 0509. this is free if you buy everything.

2 - Dayton audio 6.5 inch designer series woofer. quantity = 3. two are tested and like new and have solder residue. one is new. https://www.parts-express.com/Dayton-Audio-DS175-8-6-1-2-Designer-Series-Woofer-295-428?quantity=1

3 - Dayton measurement mic with calibration gragh. new https://www.parts-express.com/Dayto...1Qb6g07lZP4sLsTooJmKa1ABDgWreSYcaAtHpEALw_wcB

4 - pair of peerless tweeters NEW
https://www.parts-express.com/Peerl...50U221j7tfuh5fhWG-HswPDSEVg4XRFAaAo4GEALw_wcB

all together $155 paypal friends and family
weight is almost 20 pounds for the whole thing

If anybody has a surplus pcb for pcm63 dac, please let me know.
From Miro for example, the ordinary one, or some other.

It can be empty, half finished or finished and with or without dac chips.

Tnx. 🙂

Roederstein draloric 0.60w resistor

I heard these speakers by someone who tried to build Dunlavy SC V1 clone type speakers. They used two Focal Audiom 15 inch woofers. The model number for the woofers were 15VX. These were top of the line Focal Audio 15 inch woofers, 2 Focal Polyglass midbases. The model number for the midbase was 7K6411 and a Raven R2 ribbon tweeter.
The speakers were about 6 feet tall and weighed 335 pounds.

They speakers had a nice soundstage and the bass was tight with good extension. These woofers were very impressive.
Now, he couldn't do a crossover like Dunlavy. Dunlavy could make speakers that used ok drivers, but make the speakers sound great.

I remember i heard the Dunlavy SC-IV speakers that used all Vifa drivers. These speakers had an amazing soundstage and sounded very layered and the bass was fast and tight. I always though what could Dunlavy have designed using top of the line drivers like Focal at the time or Scanspeak.

Here's a pic of the speakers he designed.

Fourteen days ago, on October 1st, Wayne Colburn presented his Pearl 3 phonostage design at the 2023 Burning Amp Festival. Today I'd like to unveil "UDP3", a PCB which makes it relatively straightforward to build an external power supply for Pearl 3, in a separate chassis, connected by an umbilical cord. A few reasons why builders might wish to put Pearl 3's DC supply in its own box, include:

• This lets you move the mains transformer far away from the sensitive Pearl 3 PCBs. Greater separation gives greater isolation.
• The external PSU chassis provides an electrostatic and electromagnetic shielding box, surrounding the mains transformer. This dramatically reduces noise radiated from the mains transformer and wiring.
• If desired, you can build an additional box-within-a-box, thereby double shielding the mains transformer. You don't have to worry whether the extra size and volume of the second box will intrude upon the Pearl 3 phonostage PCBs.

The UDP3 board (Umbilical Cable Driver for Pearl 3) is shown below. It requires a dual secondary power transformer (2 x 22VAC RMS) which is not mounted on the UDP3 board. Many builders will probably choose a blue encapsulated Toroid from Tamura or Amgis, 15 VA, mounted on a blank piece of experimenter's perfboard.

The UDP3 circuit is a cascade of several lowpass filters connected in series; it is NOT a voltage regulator and there are no negative feedback loops. This is intentional and deliberate; NFB loop gain generally falls as frequency rises, often at a slope of -20dB per decade of frequency. But we want lots of attenuation (a/k/a "PSRR") at high frequencies, exactly where NFB regulators poop out.

Instead, UDP3 uses ferrite beads and several cascaded filters (one of which is a two-pole LRC filter), to achieve excellent noise reduction even at radio frequencies. The big idea is: provide Pearl 3 with a pair of low-ripple, low-noise, RF-free raw DC voltages, and let Pearl 3's onboard voltage regulators do their job, when given pristine inputs.

The UDP3 outputs plus and minus nineteen volts (approximately! remember, UDP3 is not a regulator), which the 7815 and 7915 voltage regulator IC on the Pearl 3 boards, then reduce to smooth and regulated plus and minus 15 volts.

CIRCUIT DESCRIPTION

(You may want to open the schematic image in another window, or print it on paper, to follow the discussion in this section and quickly see which component is "C5", etc.)

C1, C3, R1, BR1, and C5 form an unremarkable, ordinary AC-to-DC rectifier and filter, plus Quasimodo snubbing. You'll notice I have used C3 = 1000 nanofarads, and 1000 != 150. I spoke to the Quasimodo inventor about this, explained my reasoning, and got his approval. So use 1000 nF in your build (see Detailed Parts List) and be happy.

Then ferrite bead FB1 converts high frequency noise on C5, into heat. The ripple waveform (now on C7) has far less high frequency noise.

NPN Darlington Q1 and its supporting components, forms a capacitance multiplier that is protected against overvoltage (ZD1) and turn on/off shocks (D1). Resistor R3 ensures that the collector-base voltage of Q1 never goes negative ... which could allow input ripple voltage to shoot straight through to the output.

Then L1 + C13 + (the DC resistance of L1) form a two pole LCR lowpass filter, attenuating high frequency noise quite effectively. The relatively pure, low noise DC signal on C13 is presented to Q3 and its supporting components.

The Q3 circuit can be considered a "clamped capacitance multiplier" because its output voltage is clamped and cannot exceed (approx!!) 19 volts, even as the input voltages rises far above 19V, thanks to U1 and ZD3. The relatively weird and unknown (but extremely CHEAP) adjustable shunt reference part called AZ431AZ is used, because it offers plus minus 0.4 percent accuracy for less than USD 0.50. Much better bang for the buck than the T.I. "TL431" which is pin compatible but less accurate.

Finally, there is an output rail fuse F1 and a ferrite bead FB3 to remove the last vestiges of high frequency noise. The fuse, a small thru-hole packaged device, blows if/when you mistakenly short UDP3's output. It is available on DigiKey and Mouser for about 40 cents per fuse. Because they cost so little, I recommend you buy at least six fuses of each of three different fusing currents. Or more. Now when you get a surprise fuse-blow event during testing, you will have plenty of spares, and they don't cost an arm and a leg.

To test the first UDP3 prototype, I connected a pair of 100 ohm, 30 watt resistors to the UDP3 outputs (see photo below). These are cheap to buy and build, I suggest you get some too and test your UDP3 carefully before hooking it up to your precious Pearl 3. At plus and minus 19 volts output, these load resistors consume 190 milliamperes per supply, comfortably more than Pearl 3 draws. During testing with 190 mA load current, fuses rated 250 mA never blew.

HOWEVER, it's all but inevitable that some "hot rodder" types of builders, will add high current discrete opamps to Pearl 3. And increase the bias current in the BJT output stage. And possibly other stunts or gymnastic shenanigans which are unimaginable at the moment. Therefore UDP3 is deliberately over-designed, to provide 350 mA from +19V and 350 mA from -19V (with higher current fuses fitted of course!!) Heatsinking the pass transistors lets them operate comfortably even at these high current levels.

Schottky diodes D5 and D6 are panic protection components, whose only job is to set the rails to not-stupid voltages after a fuse blows.

WHO SHOULD COMPLETELY IGNORE UDP3?

A quick glance at the UDP3 schematic reveals that there are a LOT of components. Including four Euroblox connectors, four extruded aluminum heatsinks, eight super-low-ESR electrolytic capacitors, oh and by the way, a second chassis (!!). If you're hoping to build a cheap, cheap PSU for your Pearl 3 phonostage, this isn't it. Too many parts.

Similarly, if you're hoping to build a teeny tiny PSU that occupies very little chassis volume, UDP3 isn't for you. PCB size is 112mm X 132mm (mounting holes 100 x 120) and the heatsinks are an inch tall (25.4 mm). That doesn't even include the power transformer. See the photo of UDP3 atop a 170x230 Modushop "Galaxy" below.

Finally, if you're hoping for a "paint by numbers" audio project that doesn't require you to reason about electronics, not even once: UDP3 may not be a good project for you. There's no wiring diagram, there's no suggested part numbers for the AC mains IEC inlet or fuse holder or on/off switch, there's no transformer mounting recommendation, the list goes on and on. Avoid misery; don't attempt UDP3 if it is beyond your current builder-training-and-skill level.

ATTACHMENTS

The schematic, detailed Parts List, and PCB manufacturing Gerbers (.zip archive) are attached to this post, below. It is "Rev.A" -- the first official release of UDP3.

I've also got a few extra PCBs of the experimental prototype (rev.0) which are built on extra sturdy 2.0mm thick fiberglass, and are 50% stiffer than standard PCBs. {remember, stiffness is proportional to thickness squared}. Send me a selfie photo of yourself holding up your two chassis for Pearl 3 and UDP3, also holding the two bare Pearl 3 boards, and I'll send you a rev.0 UDP3 circuit board for $5.00. That's the cost of a mailer envelope and shipping via USPS.

his has been discussed on and off in the forums... I finally got around to designing and building an interface for using a sound card for making masurements.





Details are here: Soundcard Interface

Pete

Today (just after only 19years of usage) discovered that PMD100 suports 88.2khz rate in real world conditions(cs8414 receiver and kernel) 96khz sound can be heard but very discorted. two units tested in both 16 bits RJ and 24 bits LJ modes.


tried NPC SM5842APT in same DAC - works up to 48khz 88.2khz and 96khz very discorted and very loud(full scale output to DAC)

Datasheet says PMD suports up to55khz. And yes I am sure source exact 88.2KHZ saple rate.

What a surpsise

Very nice condition reading close on DCR .$150

March 2025 marks the 20th anniversary of Mauro Penasa's "modest contribution to this forum" (his own words) - the "MyRef" composite LM3886 amplifier. I thought the anniversary is a good excuse to design a new board for the MyRef. It turned out pretty nice, so I'm sharing the results.

The MyRef remains one of the few published composite chipamp designs. I built my first MyRef back in 2011 - on Mauro's original board, with my own relay-based 96-step volume control - but I always wanted to build a better version.

Here it comes, mounted on a 2U (80mm) heatsink:


The board for one channel is 90x50mm, all through hole, with two layers. The schematic (see post #3 below) closely follows Mauro's original Rev.C. However, I took the liberty of adding regulators to the LM318's power supply; the two TO-220 regulators are visible in the photo above. The board includes neither raw power supply nor speaker DC protection, both of which I implemented separately.

The linearity is pretty nice for such a simple amplifier:

More spectra are attached to the post #14 below.

Also, while developing the above board, I designed another, for a simple non-inverting LM3886 based amplifier according to the datasheet schematic:

Mechanically, this board is identical to the other one. My objective was to test some ideas for board layout and routing, but this board also turned out quite nice in its own right. The schematic is attached to the post #15 below, measurements - to #16.

If a crossover design calls for an 8mH / 0.790 Ohms and the two closest options are 8.2@0.800 ohms (Solen) or 8.0 @ 1.75 ohms (Janzen), which would be better or does it even matter? Actually I've already purchased the 8.0/1.75 Janzen which I suppose I could return. Any issues with either of these? If it matters, this is for a first order XO on the woofer with only a single inductor. Thanks

Let me start to say that this is only simulation with SPICE.
But I have no doubt this amplifier should do very well for real.
I challenge you to do something like it or even better 🙂

Design goals:
1. Fully discrete
2. Max 3 transistors
3. Voltage gain 4-5
4. Load 1Vrms into 4.7kOhm
5. Regulated 12V supply

Result in SPICE:
1. Voltage gain 4.6
2. THD 0.00011%
3. Frequency response 5Hz-300kHz -3dB

Hello,

I am no expert in tubes at all and have an amplifier built from the kit purchased on Aliexpress:
https://nl.aliexpress.com/item/1005...3Lcnrian&utparam-url=scene:search|query_from:



I have a pair of 300B EH tubes which I would like to use so I am thinking to repurpose the chassis and power supply for new build.
The goal is decent amplifier, not crazy hi-end stuff, let's be realistic here. So my main question is what would be the way to go: can I reuse the output transformers? What to choose as the first stage?

I've been told that I cant go by the factory FRD information and that I'll need to some software to gather the correct info to start designing my crossovers. My question is, how are you running the speakers with no crossovers? Are you running individual drivers? Wiring everything in a series or parallel to an amp terminal? Last, what app or program does everyone rely on to get accurate information?

I have made 5" version of TWTD.
















---- Alpair10.3 + TWTD at YouTube ----

Tapered Wave Tube with Damp Duct(TWTD) + Alpair10.3 - YouTube

I made this grasshopper script a while back that would dynamically make a multi entry horn from the output of ATH.

This is the sort of output you get



There is a lot of options down the side to adjust the ports and other things



The input it takes is the slices output from ath, you can select it using the Ath Slices File input (Right click and select one existing file)



I didn't end up adding the cone plug which I had planned to do, you can easily change all the dimensions currently then export it to some other software to slice up and 3d print.

I have uploaded the grasshopper project file if anyone wants to have a go with it.

This thread is about all ways to use OpAmp as input stage in power amplifiers.
Let us see your way to do this.
There are many ways to make an opamp control a power amplifier.
There are good ways, I am sure - and less good ways.

I have one way up my sleeve now, but I also have Choctaw in another thread.

I have been looking around for a 15" driver for a new OB/dipole project. A driver that is not really a subwoofer with high Xmax but rather a pro audio driver with decent specs and good HF extension that could be used down to 70-80Hz. I found the SB Audience 15MWN700D, which was just released in mid-to-late 2024:
https://www.sbaudience.com/index.php/products/woofers/nero-15mwn700d/
This is a bit of a head scratcher for a pro audio driver. Qts is not low and Xmax is not all that high. I suppose it could be used in certain applications but it doesn't quite fit the mold in my mind. But it does have very low Le and uses a copper sleeve in the motor. It seems this driver has been designed more for clean performance than outright SPL, etc. and its passband extends up to almost 4kHz with only mild breakup. With its open basket it seems like a good prospect for OB use even if it is not designed or intended for that purpose.

I did some modeling about what I could expect if the driver were used in a small baffle as part of an OB system. As part of the modeling I included series impedance of 6.8mH + 4 Ohms to both flatten out the dipole response and reduce the distortion produced by the motor. With 200W input power and a modest baffle the system can produce over 110dB SPL from around 80Hz to 300Hz, which is perfect for my use. At this power level, the 15MWN700D will exceed Xmax below 55Hz without a HP crossover, however, I would use a subwoofer below 70-80Hz so the size of the main speakers remains modest. I typically cross over to a nude midrange driver around 300Hz and I am thinking of using the Satori MW19TX plus a large AMT tweeter to complete the system (I already own these drivers).

I have not seen any testing or measurements of this driver, but given the MFG description of the design I am optimistic.

I thought I would toss this thread into the wind in case others have been eyeing this new offering from SB Audience.

Hello diyers,
I've been playing sub-less for few months but with time I realised I was really missing a clean first octave.
My boxes are not able to go very low, it's 2x 15OB350 per side in around 200 L.
They can go low with EQ of course, but they just sound better crossed around 35/30hz, lower is just noise.
Don't know if it's the drivers high fs/qts, the "still" too small boxes or maybe not strong enough, or the room placement, probably all combined.
I see them more as big mid-bass in fact.

I had in mind to upgrade the drivers at one point, for the nero-15sw800 that should better fit the needs, but even if they're not that expensive it's still four of them that I'd need. And more important I'm not 100% convinced it will be a big improvement due to the mains placement.

So before going there I have to try spread bass again, within following constrains:
1 - nice look and integration with furnitures
2 - high sensitivity
3 - critical damping if possible

#2 means big drivers, I still have my four 18sw450 from my previous dipole, why not using them?
#2 and 3 kind of go together, but against #1 for the size implied.
#3 is a way to finally decide for myself if an L/T box can really sound the same as a big natural one (and I believe not, but lets' test).

I started with what I had around and within the new room layout constrains, with a sealed um12-22 in maybe 100-120 liters (much bigger in real but with sand walls) right behind me.
Not bad at all but not enough juice, plus it's not easy to nicely integrate with the furnitures.
I couldn't try my old concrete ported one as I got rid of it few months ago (and for that I had to destroy it in place, too heavy to get out 😛). I don't regret, it stayed for years unused in the same spot, it was fun to build, but also just too bulky, and too hard to move around to test different spots.

So, I had to find a way for 2-3 subs, placed behind me, light enough to move around a bit, but big enough to not require an L/T, easy?
Thought about it few months ans was about to buy woods when… again my favorite/hated shop just launched a new serie: the rådmansö.
Beautiful pieces in my mind, I would have loved to start with these when I've built my mains, a lot of cool stuff could be built around them.
Went to see them in real, and realised even the big one could do it, this one, 159x64x46cm, 468L. :




Got one, some mdf, some valchromat and let's go.
Like previous stuff I've just built a box within a box, 18mm glued all around inside, 24mm for the back, half the baffle doubled in valchromat, bracing with scraps, kind of light. The good surprise is that the radmanso is full particle boards, no honeycomb core on this like on many others, so nearly 4cm thick particles + mdf at the end.
The baffle is removable so I could add more bracing later if needed (I already found a spot that may need it).
And I could try 1 or 2 drivers, even clamshell isobaric if the box is still not big enough 😛
It's around 330-350 L. I'm guessing. Yes I did some sims but, they're just sims…

I of course did few mistakes again, my very first move was one! While sanding the inside of each panels for better glueing, I messed up and sanded the wrong spot of the panels, the edge that would have been visible outside. So I couldn't get the recessed baffle like I initially wanted.
Damn' what an idiot. So the baffle is now flushed, I'm sure it would have looked much better with the recess (like the mains).
Maybe I'll add a fabric grill, I'll see, it's fun to see the big driver too.
Then the valchromat was finished with tung oil, for a nice dark contrast.
Some details are left for later like the right cable, neutrik connector, better driver screws, replace temp wheels once in place to decouple a bit etc.
Not sure I’ll use the original steel stand that comes with it, it’s sturdy but will add 20cm in height.




I quickly plugged one little fosi on it yesterday and it seems promising, efficient for sure.
I hope I can move it in the right place soon to measure it.
Meaning right below the diffusors behind me, where I now have a bunch of besta used for storage.

In all this I kind of try to find the same effect I had in my car years ago. I might repeat myself but it was so fun with 2x15'' at few cm right behind the head. Breathtaking was the right word, literally, and I'm not talking SPL, just air movement in your lungs even at low levels, like someone with a pump trying to empty your lungs at every beat!

Of course home environment is a total animal but if I can get 10% of this I'd be happy 😛
Will come back with measurements soon, if a success I will build another one, and maybe even 3 in total.
Cheers!

I am new to the world of personal audio. I come from a background of music appreciation/collecting/archiving and a bit of hobby digital DJing (yes, I am not a "real" DJ lol). I decided to introduce my wife to DJing and my first step was to purchase two V-Moda M100 Master headphones (for shared listening) and Pioneer DJ VM-80 speakers. In order to connect these to my laptop, I bought a Zen DAC 3 and an iFi Audio 4.4mm to XLR cable one month and a Zen CAN 3 the next month. I use an iFi Audio 4.4mm Pentaconn analog cable to connect them. After I did that, I bought two iFi iPower X power adapters. Each step in this process brought even better audio to the setup.

I joined a message board and began to look for ways to improve this setup even more and came across information about what is the best USB cable to purchase. I was informed that isolators/regenerators/reclockers were good to have as part of the chain between laptop and DAC, and I was recommended to purchase an Altor T1 from Alex Torres.

The small .070 gram USBISO arrived after a month and both Alex and I were challenged to figure out exactly what was wrong with it. In the end, I realized that nothing was wrong with it! This is how we figured out together what I had to do to get it running.

When I first plugged the USBISO to the DAC, there was no connection, but its red LED light was lit (even before connecting it to the first iPower adapter that came with the Zen CAN 3). I used a Gothic Audio Semper Fi The Outsider .3m cable for both before and after the isolator. So, that was strange. Later, Alex suggested that I should connect either a removable storage or mouse to the isolator, which I did, and there was "energy" but no "data" running between these.

Alex didn't know why and suggested that I should return the device, but I decided to run a diagnostic because I didn't want to give it up so easily to return it for a refund or exchange. I chose to run this particular diagnostic by connecting the isolator to my wife's laptop and I noticed that immediately the cursor worked. So, that was interesting.

Here's the key part of this story:

My laptop is relatively new, purchased in January of this year. When I got it, I did something kind of geeky and tried to remove everything that I thought was nonessential, however, in the process I most certainly removed something that communicates data between laptop and devices. I am not sure, then, why the DAC worked, but I decided to save all my data and reinstall_Windows. That allowed my isolator to work. Problem solved! I am not sure how the Isolator sounds without the Gothic Audio cables but the entire setup sounds great. I am very glad for this tiny device, but most of all for Alex's patience and guidance because I tend to overreact and send multiple panicky messages before he gets a chance to write back.

There is so much more that I can do with the setup, but given a limited budget, I am going slowly and step by step to try to have the ideal setup for our little jam parties at home.

For sale is a Gainclone amp I built some years ago and hardly used. It's a little dusty but fully functional except it needs RCA jacks and binding posts. It could also use a better enclosure than the one you see in the picture. Uses the LM3875 chip. Asking $75 OBO including shipping to CONUS only.

I would like to have something that can increase (I already know how to decrease) the damping factor without adjusting the amplifier feedback, such as filtering, preamp, DSP algorithm, or similar... I have seen a DSP algorithm that can increase DP but don't have access to it. I would be grateful if someone could provide even a little information