MA200-M was broken in for 10 hours before being measured and air-recorded.
MA200-M is a driver that combines the powerful sound of the W8-1772 with the silky sound of the MAOP10.
My standard go-to recommendation for most displacement per $ for years now have been the Alpine SWG-1244, at 12" membrane area with 1cm Xlin ((Hvc - Hg) /2) for ~80$. Before that, I used to recommend the Thomann 15LB075, which since its price increase to 75€ has become uncompetitive.
I recently got around to measuring the Alpine, compare it with other products, and more or less confirm the manufacturer performance claim -> Review on Youtube
Popular alternatives are largely uncompetitive from a price/performance standpoint, or unavailable:
GRS 12SW-4HE (12", 12,5mm Xmax according to manufacturer (no explicit Hvc and Hg), 65$) - out of stock everywhere as of 03/25
JBL Stage 1210 (12", 11,35mm Xlin, ~80$) - out of stock everywhere as of 03/25
I thought it's worth to have a separate thread on the subject.
Many of you like and run Logitechmediaserver based streaming solutions.
I couldn't agree more to that choice. It's IMO the best solution out there.
However. Until recently the available user interfaces were OK. And that was about it.
I've been running Orange Squeeze and iPeng for years.
That changed some months ago.
There's a rather new kid on the block.
Material Skin (MS)
This new community provided feature brought the LMS package to a whole new level.
Material Skin is an advanced LMS User Interface (UI) using latest web technologies.
You can simply install it via LMS Settings/Plugins.
Once that is done you access it via " http://192.xxx.x.xxx:9000/material/" from a browser.
You simply just add "/material" to your known LMS server IP.
That works on any browser in the network. MS offers desktop and smartphone modes.
Once you've bookmarked MS, use the "Add Bookmark to Home" feature that comes with most of the browsers to pin MS to the homescreen. It works on Android and iOS.
Change the layout/color scheme to your liking. And make it "default". You'll then have the same layout on all platforms. Which IMO is an awesome feature!
Suddenly you have the same look and feel on all your control clients - it'll give your streaming setup one look and feel throughout the house.
I tested it also with Qobuz,Tidal and Spotify. Works great.
All my external control apps are gone now, replaced by Material Skin.
Not to forget. MS is actively being developed/maintained. (Let see how this develops over time.)
Advise: Make sure you run the latest LMS. Download and install the latest 8.0 nightly build.
If you run old/outdated LMS versions, you might have problems getting it to work properly.
Bottom line. If not done yet. Just give it a try.
Thx to Craig for his excellent work. It's highly appreciated.
i am a sound system passionnate and i would like to learn about loudspeaker simulation in deep details, hope this is a good place and people here will be able to explain me what i dont understand.
I just raised this question on another thread, concerning high quality electrolytic capacitors. But I think it should concern other parts.
China has a bad name for having made fake parts for many years, both passive and active ones.
The only Chinese brands I have seen being offered were electrolytic capacitors, and some really dirty practices were used by many, but mostly on parts using a false name and being really fake. Like putting a small capacitor inside a larger case, which can be considered criminal because of the dangers implied.
But what about those with new, unknown brand names, trying to sell a legitimate product, good quality ones?
Let's talk about passive parts first: resistors, capacitors and inductors. What we diyers should forget is that any of those potential or existing manufacturers will setup a production of old, non-SMD parts, which will demand a serious learning on how to solder SMD parts from old-timers like me. We are too small a market to attend to.
So we are left with at least someone making the bigger size types, which now I think it is 805, am I right? Can you find a discrete type resistor or capacitor or diodes that is larger than that?
And then we get to active parts. China seems concentrated on the digital application, computers and communications and similar. Nothing mentioned on linear devices, like discrete transistors (particularly FETs) or advanced linear opamps that can be used for audio analog stages. Am I wrong? Is there any Chinese brand interested in that market, if there is any?
Until quite recently the concern was about regular side linear parts becoming SMD types, now it seems the concern is out very existence as DIYers. Do we have a future?
Will the fake market become legit and make active parts that up to the ones we are buying from Mouser or Digi-Key? They already warn that some parts can't be exported and their very high prices are also a concern for us. We find many active parts being offered on AE which we do not know the origin of, are they legit or fakes? Are there exceptions? Will there ever be?
What are our options for those living outside the USA?
This poor thing was going to be thrown in the bin (some will say they would have i know 😉 )-but i saw this as a real challenge as its realy in a bad way.
so here we go this is it, and there is lots to do.
The cover will need to be stripped, repaired and recovered.
The amp, completly stripped down, a realy good clean,get rid of all the rust, reacap
Im going to have to strip this right back to bare bones.
Looking at the set up it might even lend itself to a simpler circuit and laterals??
Hello All,
Looking for linear voltage regulators that have input around 55 V and output 50 V and can handle 5 amps. Also need the complementary regulator for -55/-50 V. Are there any ready components? I'm having great difficulty to find any. (Otherwise I'll have to build one myself.)
Martin Albers
This thread will follow my build of the Halcyon speakers, designed by Curt Campbell. I'm not sure if this is technically a F.A.S.T design, but I think it is. There is a single Alpair 10p and two SB Acoustics SB17 midwoofers. Curt described the design: "The Alpair is housed in a semi open back cylindrical enclosure, while the SB17's perform in individual transmission lines that are merged at the port in a mass loaded configuration"
Curt shared that one of his friends, a professional opera singer, preferred the Halcyon's to any of his other higher-end designs. This raises my already high expectations that this is going to be a fine speaker indeed. Strangely, other than Curt and Jim Holtz, I don't know of anybody who has heard them and I don't know how many pairs have been built. Madisound says they have sold several kits, but I haven't been able to find a build thread or any pictures of completed Halcyons other than the original test mules.
Bob Berner (bob@bigwoodstudio.net) made a terrific flat pack for the Halcyons. Everything fits perfectly and the BB plywood is very high quality. Bob is very helpful and prompt. From idea to delivery for a brand new design with no CAD drawings, Bob completed the whole process in just a few weeks. He is great to work with (he also built a FruglHorn XL kit for me) and I encourage anybody interested in a flat pack to contact him. He has good prices, great service, and a very supportive approach.
Hi,
I have only been seriously reading up on speaker design for a week but even so it is obvious to me that the USB vs XLR microphone issue for driver measurement and crossover design has been thoroughly worked over. I half understand the difference as it related to timing and the superiority of an XLR microphone in this regard. I also have seen the unambiguous advice from Kimmo Saunisto on using XLR for measurements for use in VitruixCad.
However I also read the ASR guide that everyone seems to refer to: "How to make quasi-anechoic speaker measurements/spinoramas with REW and VituixCAD" - and it advises use of a USB Umik.
As I already have the Umik I am not really keen to buy another microphone unless it is truly necessary. So if anyone can explain the apparent conflict or perhaps clarify/quantify the real world impact of using the Umik I would be most grateful.
Cheers
Bill
This is a shared DIY project, for non-commercial use. It consists of a PCB and firmware for the chosen processor module:
2 (0, 90°) or 3 (0, 120°, 240°) phases of sinewave generation, with electronic speed switching between 33 or 45rpm
optional tachometer, with configurable pulses-per-rev and averaging (requires external sensor providing logic level pulses)
OLED display (SSD1306, SPI or I2C)
buttons or rotary encoder support for stop/start, speed switching, frequency/phase adjustment and menu operation
selectable soft start amplitude or frequency ramp, to support different motor types and setups
selectable delayed reduced amplitude, separate settings for each speed
configurable frequency-dependant-amplitude to maintain constant current/torque at different speeds
menu system for all settings with live adjustments, saved in non-volatile memory
RP2040 processor based module with easy drag-and-drop firmware upload
Latest updates:
17-Mar-25 firmware update correcting negative phase saving error, see here 09-Dec-24 firmware update adding frequency-dependant amplitude feature, see here 29-Oct-24 firmware update adding frequency ramp feature, see here 25-July-24 PCB updated to v3.1, minor footprint updates but no change in functionality, see here 14-Jun-23 new PCB v3.0_PICO for Raspberry Pi Pico, see here 04-May-23 update to RP2040 processor, compatible with Nano PCBs, see here
This is the sinewave generator only, and will require amplifying to the target motor's voltage. A 2 or 3 channel amplifier is needed to either directly drive a low voltage motor, or line level motors via suitable step-up transformers. (A low voltage amplifier for driving a 24v 2 phase synchronous motor is detailed here).
Gerber files for the latest PCB and build guide are attached to this post.
The original Uno/Nano processor/firmware is retired and no longer supported. However, those with existing v3.0 and v2.0_NANO PCBs can still use them with the RP2040 processor/firmware, configured according to the latest build guide.
I'm currently working on an XXV Sampson, the power supply section comes on and relays click and I get a green status light. When i probe the FDA 24N40F output FETs, Q19-Q16R and Q11-Q13R are shorted, the same FETs on opposite sides of the board which is too coincidental so I get the feeling the output driver board could have an issue.
Mr. Perry Babin sent me a schematic of a similar board and reading it without any electronics repair training is proving to be a tough task but I'm slowly researching the components but I could really use some assistance with this if someone could lend some.
Also, if I'm not mistaken the FDA 24N40F wasn't the output FETs on the board before it was sent for repairs this last time. Is this component a proper FET for this amplifier?
As always I'm very grateful for any help I can get. I will try to post the best pics my phone can take and if there are any more needed I'm happy to take more. Thanks again
Trying to use dmm for amps but with gain at full blast it still only reads 20 volts.im looking for 38, way off. I've tried fluke , Klein, Milwaukee even harbor freight. None will go over 20 volts. Keep reading turn gain up till desired voltage , bam done . Not understanding.
Hello – I found an old Sonos soundbar at home a long time ago that’s still working and sounds great, but unfortunately it only has an optical input and my PC (which I want to connect to it) only has an AUX output. Since I have to do a school project for which we have one month, I decided to build an AUX‑to‑optical converter. Unfortunately, I couldn’t find any schematic for an AUX‑to‑optical converter online, and ChatGPT wasn’t able to help me either. Now I’d like to ask the DIY Audio community if someone could create such a schematic. You don’t need to do the PCB layout—that I can handle myself. The converter should also be stereo, since the soundbar supports that. Our only rule was that we weren’t allowed to program anything. And if possible, it should cost less than 50 CHF, as that is our budget limit, but if it goes over, it’s not too bad.
Thank you for the quick replies. I wanted to clarify a few things that might help solve my problem.
My PC has a Line-Out port with a green ring, which is for audio output, and I want to connect it to a Sonos soundbar.
I also checked, and my PC only has 3 x 3.5mm audio jack connectors (green, pink, and blue). They are all analog and directly connected to the motherboard. Other than that, I don't have any additional audio outputs.
The Sonos soundbar has a Toslink (optical) input.
I'm into audio restoration and preservation of analog sources - LP's, 78's, tapes, etc..
The problem I have had over the years is excessive gain from my phono preamp driving my sound cards. The audio card mixer can turn the volume down, but cannot do anything with an overload input signal. I started with a Hoontech/STAudio card, updated to a M-Audio Delta card, and now I'm using an ESI Julia in my newer computer, but I still had the same issue.
To solve this problem I purchased some F-Mods from Parts Express. This helped, but couldn't stop wondering if they were adversely affecting the sound. In an attempt to improve, I replaced them with a pair of higher quality Rothwell inline attinuators. But I have read even these affect the sound.
Both of these units use simple resistors. What bothers me is I have always been with the understanding that resistors are not the right way to do it. LC attinuators are the ONLY proper approach. But the only ones I can find anywhere are only for use with fiber optical audio. What am I missing here? Any suggestions?
Which are the "best" Compression Drivers today in the Year 2022?
Yes maybe TAD but I mean something which is payable. I don't want to spent 4000€ for one Driver....
Hello! I’m planning to rebuild an 3553 alpine that I’ll be using for midrange and tweeters. Till now I changed the power supply caps and voltage regulator pair of transistors tta-ttc, 2 Zener diodes. My question is on the signal path per channel I have 10uf , 100uf BP and 0,47uf. The 100uf I used muse BP , on the other hand I ordered wrong some Panasonic fc that are tiny(miniature) and nichicon uep BP. Now I put the Panasonic fc in the place of 10uf. It is a good ideea or I have to order some new ones? Seems impossible to find good 10uf for audio path. Also I ordered sip adapters for njm and I will replacing with opa2134. Some caps are a little bigger than original and stay on some resistors, is this gonna be a problem? Any advice is well regarded.
We have some nice powered subwoofers from Vera-Fi Audio.
The Caldera series comes in a 10in and a 12in version. Both are thin channel vent slot reflex designs. The 10in comes with a quality Class AB amp with a linear toroidal trafo and the 12in comes with a Class D amp with a linear toroidal trafo. Nice cabinets and class leading powerful motor drivers.
Recent review (and teardown) of the Caldera 10 here.
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We have to fix the power specification. It should be 175w peak power for the Caldera 10. The Caldera 12 should be 250w peak power. Since drivers are very high sensitivity, this is plenty of power.
The review and teardown of the Caldera 12 is here.
Heard these recently, really loved them, and now plan to build them. Others embarking on the same journey, please share! Ideally this thread can concentrate the latest design notes, guides and user builds.
My plan is to biamp, keeping the passive crossover between the 15OB350 and 15CXN88 mid-woofer. It seems a more elegant and reasonable solution than triamping, although the triamp route is tempting. I'll do a 5º tilt and shrink the sidewings just a little (for an overall depth of 23" instead of 26"). Design files attached. Perry, off the top of your head do you know how much low end is lost per ~3" or 6" of shrinkage on the sidewings?
Re: FIR filtering and miniDSP. From what I can tell, the miniDSP Flex Eight has FIR filters on the inputs, the Flex Balanced has them on the four outputs, and both share the same total number of taps. It looks like the Flex HTx and SHD do NOT allow user-created FIR filters. I assume Perry's files will only work on the Flex Eight, but it shouldn't be difficult to copy the settings over to other units.
I'm tempted to use the miniDSP SHD instead of Flex, with Dirac enabled. Streaming, preamp, crossover all in one box would be nice and tidy. @perrymarshall, am I correct in thinking that the main compromise with that approach is forfeiting the phase correction and phase benefits of FIR filtering in the upper range EQ (top 2 octaves?)? But Dirac should take care of that anyway? Any other issues or complications to know about if using the SHD instead of Flex?
Hello, I recently bought a really quite nice sounding Amplifier of amazon. It sounds great for the price, but as soon as I turn the volume up to max, it starts cutting in and out.
My setup:
2*60W 4ohm speaker
1*150w 4 ohm subwoofer
I'm going to take a guess that some sort of protection system is kicking in. It says it has overvoltage, undervoltage, overheat and "DC detection". It's not overheating, I measured the 19v power supply s output voltage and it stayed constant. So the only thing it could be is DC Detection.
Is the duty cycle going too high on the output??
I would be really grateful for any help 🙏
I built it 8 years ago using cheap $5 woofers and cardboard. It sounded so good, I made a note to myself that I must revisit this one day as a proper speaker in wood.
That day has come and I am so glad I returned.
Predicted (black) and measured frequency response (yellow):
Harmonic distortion at 1W:
Impedance as seen by amp (it’s a 4ohm speaker):
You can listen to the sound here with the midrange driver I finally decided to use - PRV 5MR450NDY: Login to view embedded media
Passive crossover design (values redacted because this is a commercial design):
You are welcome to build it using active DSP and I will give you all the info needed for the crossover slopes and frequencies (470Hz and 4700Hz). I managed to do this 3 way with only 12 components. Possibly 11 if I replace the big electrolytic/film combo with a single large value film cap. If you want to do a passive crossover, you will have to be on your own. I’ll give hints but please understand that as a commercial product I can’t give that out for free.
Detail of the planar tweeter (GRS PTT2522-4) with custom CNC’d waveguide and PRV 5MR450NDY midrange (those of you with hawkeyes might notice the PRV is labeled 4ohms - it’s actually an 8ohm, mislabeled as 4):
Detail of midrange and tweeter from the front with painted baffle board (paint is Rustoleum Uni“Oil Rubbed Bronze” for those interested):
You can see that the phase variation of the tweeter and midrange through the 4700Hz crossover range is very smooth as the phase is almost flat. This would indicate a near quasi transient perfect time alignment of the midrange and tweeter. This will give very convincing percussion and snap for things like drums, guitar, piano, stand up bass etc. The woofer however, because it’s a slot loaded design, has some inherent time delay that’s not so easy (impossible) to make transient perfect with a passive crossover and a flat baffle. However, this doesn’t detract from the realism as the bass below 500Hz doesn’t define the timing realism from a listening standpoint. Plus, this is an open baffle design and the sounds come from many reflecting surfaces front and back of the speaker just like a real drum or bass would sound in a live performance.
Here is how the slot loaded woofers are setup. They are arranged cone to magnet but wired so both diaphragms push the air out of the slot on a positive signal. This allows the natural asymmetric suspension non linearities to self cancel. The magnet inside the chamber also reduces the chamber volume and this allows a higher upper bandwidth for the woofers. The chamber depth from front to back dominates this but the volume plays some effect. The slot dimensions are 2.25mm wide x 5.5in tall each. The idea is to have the slot cross sectional area to be about 33% of the cone area (Sd). This will give a good tradeoff in slot loading to enhance the bass efficiency and to not have too much of an overshoot. By keeping the depth of the slot as short as possible, we can keep the upper bandwidth higher. We are able to get this woofer array to play up to 470Hz before a natural band pass fall off occurs. We can use this natural falloff coupled with an electrical low pass filter at the same frequency to get a 4th order steep falloff for using only a 2nd order filter. This reduces woofer mid range leakage above its passband. Also, with opposed drivers, the cone motion vibrations end up self cancelling. So the speaker has very little vibration despite delivering a massive bass punch.
Speaking of punch and slap, this speaker has perhaps one of the best I have heard. At 91.5dB (some mid bass is at 94dB), it does not take much amp power to do this. I can easily reach loud (but clear) 85dB to 90dB SPLs at listening position with only maybe 6Vrms. It’s a very dynamic and powerful big sounding speaker. But at the same time, can play softly while still delivering very nuanced bass. Bass from dipole that is tall like this 4 slot array also has less floor bounce issues and almost no room modes. You can walk around and the bass is very uniform. The woofers I used are GRS 6.5in poly cone rubber surround 8ohm budget drivers. 16 of them will cost you a little over $200. The amount of air that can be moved by 16x 6.5in woofers is not to be underestimated. It is incredible and about a little more than two 15in drivers per side. But the front profile is much more family (wife) friendly 12in wide. The floor footprint is 12in wide x 14in deep. It stands about 45in tall
The bass arrays are built using 5 sheets of stacked 3/4in MDF:
About 8in deep side U wings surround the woofers to extend the bass as if the baffle were closer to 28in wide:
Lining the back wings with felt it acoustic eggcrate foam helps to make the sound cleaner. It’s optional though. Sounds quite good without it.
I should mention that the woofers are wired 4x parallel, then two pairs of those in series, then a pair in parallel at the end. Make sure the opposing ones are wired correctly so that they both squeeze air out when the signal is positive. This results in a 4ohm nominal impedance and a sensitivity of about +12dB on top of whatever the nominal 8ohm rating is after baffle step losses. So for an 85dB driver we get about 91.5dB at 2.83v (that’s 2W into 4ohms). What this means is that the drivers barely move for significant SPL and that leaves a lot of headroom so that the distortion is very low.
For anyone interested in building this speaker as a personal DIY project, PM me with your email and I will get you the dimensioned version of this sketch.
I’ll give you hints on how to do the passive crossover if you like but I would recommend going the active DSP route with three amps. Make sure you use one capable of 4 ohms for the woofers. It’s an easy to make DSP crossover.
In my opinion, it’s one of the best sounding speakers I have built or heard. The dynamics and visceral impact staggering. It is very realistic and can play any music genre well. It excels at dynamic music like orchestral stuff, complex metal guitar bands, jazz ensembles, classic rock, hip hop, techno, pop, and of course girl and guitar easy stuff. I am really impressed by its abilities and hope you give it a try.
If you like to listen to music with large dynamic peaks, this speaker will not disappoint. Bach’s Toccata and Fugue in D minor has a pipe organ crescendo that is registering here at 98dB at listening position 2.5m away in perfect clarity and the speaker isn’t even breaking a sweat. Nominal volume was around 83dB.
Edit May 14, 2023: I’m offering a XO kit and the CNC waveguides in the GB thread here.
Good morning, I would like to know if any of you know how to activate this power supply to check its operation. At the moment I am not getting voltages on all the pins, much less on the CN904 +31.5v pins. I hope someone can help me. Thank you!
Pair of custom Monolith Magnetics amorphous core output transformers. They are a modified version of their SA-11 offering and include 32 ohms secondaries and a 60mA gap. So these would work well with speakers as well as headphones. Specs:
Type: single-ended amorphous
primary: 5000 ohms
secondaries: 8, 16, 32 ohms
DC current: 60mA, but Monolith told me these would work very well up to 80mA without performance loss. The 60mA gap provides higher primary inductance than the stock SA-11.
power handling: 10 watts
Asking $850 for the pair, shipping included in cost. Buyer pays paypal fee if G&S. CONUS only. Save some money on import duty fees and shipping costs from Europe!
At the beginning of the introduction of AI - Chat GPT, I tried to ask about "how to make / schematic tube amplifier?" and I got a very short and unclear answer, without still not smart.
after that 2 years passed I was curious again trying to use AI deep seek for the schematic of the 10Y SE triode tube amp class A. and this is the answer! lots of convenience and very fast response! is this the era of the end of the human individual mind and intelligence, and all replaced by AI?? very scary!
I am a lucky human being to be able to experience an era without computers until the digital era. and this is really surprising !! there is a sense of fear!
And this is answer of my question :
# DIY 10Y Sylvania SE Triode Amplifier (Class A)
Here's a comprehensive guide to building a high-quality 10Y tube amplifier using Hashimoto transformers and premium components:
## Overview
This is a single-ended Class A triode amplifier using:
Power tube: Sylvania 10Y (rare DHT triode)
Driver tube: Siemens ECL11 (triode-pentode)
Output transformer: Hashimoto H14-20U
Power transformer: Hashimoto PT250
Rectifier: Raytheon 5R4WGB
## Circuit Design
### Power Supply Section
Rectification: 5R4WGB tube rectifier (slow start)
Power transformer: Hashimoto PT250 (custom spec for 10Y)
Filtering:
- First cap: 4μF (max for 5R4)
- Choke input (5H+)
- Second cap: 20-40μF
- RC filtering for driver stage
Driver stage: ECL11 triode section (μ≈70) in common cathode
Output stage: 10Y triode (μ≈8.5) with fixed bias or cathode bias
Coupling: High-quality film capacitor (0.47μF-1μF)
## Operating Points
### 10Y Tube (Approx. 300V operation)
Plate voltage: 300V
Grid bias: -35V (fixed) or cathode resistor (~700Ω)
Plate current: 50mA
Output power: ~3W
### ECL11 Driver
Plate load: 47kΩ
Cathode resistor: 1kΩ (bypassed)
Gain: ~30-40 (sufficient to drive 10Y)
## Construction Tips
1. Layout:
- Keep input wiring far from power supply
- Star grounding point near input
- Tight lead dress for 10Y grid circuit
2. Heaters:
- DC for ECL11 (reduce hum)
- AC for 10Y (with hum pot)
3. Safety:
- Bleeder resistors on PSU caps
- Fuse both primary and secondary
## Expected Performance
Frequency response: 20Hz-30kHz (-1dB)
THD: <2% at 1W (mostly 2nd harmonic)
Damping factor: ~4 (typical for SE)
## Alternative Options
Driver tube: Can substitute ECL11 with 6SN7 or 6J5
Rectifier: 5U4G if more current needed
Would you like me to elaborate on any particular section of this design? I can provide more detailed schematics, part numbers, or construction photos if needed.
The 10Y is a wonderful tube - this should make a superb amplifier with the Hashimoto iron!
Still add for simulation LT spice if you want it!!!
Hola,
Quería contarles que mi abuelo me regaló este amplificador. Como mi familia sabe que me gusta el audio, me lo regalaron, pero la verdad es que no sé nada al respecto y me gustaría venderlo.
He visto que estos son raros pero alguien podría orientarme sobre cómo saber si funciona, cuánto costaría arreglarlo o en cuánto podría venderlo?
Por favor hágamelo saber.
hello, does anyone have a diagram of the motherboard for the philips tab 8907 soundbar. The problem with this soundbar is that there is no sound, it connects to the phone via bt or using another input and there is no sound, even when turning on the soundbar there is no sound. (I saw a thread on redit and it was recommended to download the appropriate firmware via usb. Unfortunately, this method requires a remote control to enter the settings, unfortunately I do not have one)
For sale Dark LED I/V in perfect working condition with Miro's PSU and transformer. I decided to go with tube IV.
I only populated PSU pcb with +/-18V for Dark LED. There is room on the pcb to add another +/- power for your DAC or whatever else. PSU pcb is 2oz copper, gold populated with the high quality components.
Hi Guys,
I've been messing with a pair of these using the stock CPA-15 Crossover pictured. I have a pair of active JBL 2235's on the bottom for bass which are crossed over at about 100hz so I am not concerned with wringing low bass from the Tannoy. I find I get the best transition using the Tannoy 15 in a sealed cabinet but I feel like a lose a bit of output in the range that the bass driver on the tannoy is covering by having it sealed. Plus they were designed that way as they were used Soffit mounted. So I wanted to try to bring down the output of the tweeter on the Tannoy so I will get more impact from the bass unit of the Tannoy in the 100hz to 800hz that it is covering. Do I just increase the 2.2 ohm resistor and decrease the 5.6 ohm? I'm thinking lowering it 6db would be a good start. Any recommendations on values?
I'm going to build my own RIAA pre-amp. It will be fitted inside the turntable. My MM cartridge (Ortofon 2M Red) specifies the load capacitance as 150 - 300 pF. Am I better of aiming for the low side (150 pF), the high side (300 pF) or something in the middle? Besides the tone-arm's cable capacitance (some 20 - 30 pF, I presume) I can dial in any capacitive load I want. Which is preferred, or is this a matter of personal (audible) taste?
I’m dependent on matched Jfets for my amplifiers, so I have used otherwise idle time to measure, with PEAK DCA75, about 1500 pairs.
At my rate, those, combined with my untested stock, will see me well into the eighties, so I’m offering octets, four of each N and Ps, for €80, all inclusive.
Values between 6,5mA-10,5mA can be supplied.
Registered shipping, PP family and friends to EU citizens only. Postage outside EU is killing.
Hey guys,
During the years I have built a couple of speakers based on Beyma 8CX300Nd/N and found it a good-sounding driver all in all. Recently, I decided to revise the crossover design for this driver to get the best sound possible. I built a cabinet by laminating BB plywood and took some actual measurement with it and simulated it in Xsim and VituixCAD and both are pretty similar, but I was hoping to get flatter response, that's because I'm writing about it here to hear your opinions if this could be done any better.
The cabinet is a bass reflex with ~30l volume and there is down-firing port underneath.
I measured the woofer near-field response and also the far-field and merged them about 250hz. Then I measured port near-field response and compensated it according to its surface area and added it to woofer response. Then simulated the baffle step diffraction loss and imported it as a graph into REW and multiplied it to the overall response of the woofer:
here is the tweeter @1m. I was hoping the tweeter will perform better but...
Here is the simulation in Xsim using the actual FRD and ZMA in the cabinet. First I wanted to use the woofer response after subtracting the baffle step diffraction loss, but then I decided to ignore it by taking the room gain in lower frequencies into consideration:
And here is the VituixCAD simulation:
Actually, I'm happy with the woofer flatness, but the tweeter is so so and doesn't seem it can get any better than this. Any idea to get a better result is much appreciated.
What can I say, this is a superb sounding amp. Quiet, powerful, dynamic, non fatiguing, low distortion.
JPS64 created a masterpiece with his signature symmetry, via stitched ground planes, and ultra short high current traces. The board is 2mm thick, 2oz copper, ENIG finish. Assembled in California using premium genuine Mouser-sourced BOM. Each amp is individually tested on an Audio Precision test stand at the factory and then sound quality tested by myself before shipping.
Many people have assembled this amp into a nice chassis and everyone loves the sound. With the right PSU, the amp has the distinction of being the quietest amp I have built. You cannot tell it is on with ear pressed to the speaker cone. Just silence.
I hope folks will share their builds here. Or feel free to ask technical questions.
Redjr made on of the nicest implementations. More here.
Vunce made an awesome build with a linear PSU with an LT4320 Ideal bridge rectifier amp on a plank here:
For best results, this amp should be paired with the BTSB balanced buffer which provides selectable gains (0dB/6dB/14dB/20dB) SE or Bal input and SE and Bal output. Since the TPA3255 with PFFB only has 15dB gain, it needs a preamp with about 14dB of gain in order to play music to its maximum levels. The BTSB is a superb preamp design by Jhofland. It started as a GB in this thread. Here is the panel mount version of the BTSB:
Those of you who know me, know that I hate casework (chassis building). This most of my amps are “plank” amps. Amps on a plank of wood. Only the most special and deserving of amps get a chassis. Well this amp is one of those amps. More to come...
Edit Jan 31, 2023: video on how to setup and connect your amp module for the first time.
this is my first post here. I am interested in getting new speakers and upon researching I found the SB Acoustics Ara kit super interesting. To me it seems like a good price performance ratio when the drivers are presumably high-end in the speaker. Just wanted to ask, if anyone has build this kit, especially the TX kit interests me as this is about the price point I want to spend (around 2000€). Has anyone maybe also compared the normal version to the Be or TX version? Excited about any opinion pretty much 😀
Also I don't know much about crossovers yet. When purchasing, there is an option to upgrade some parts of the crossover. Do you think it is worth it to get the already made crossover of the kit and upgrade some components or are better components not really worth it compared to changing the crossover design completely which I'm not able to unfortunately because I don't know anything about it.
I expect the performance of these modules to be at least as good if not better than the Starkrimson modules.
These modules will be designed to specifically work with the Hypex SMPS1200A100 power supplies. Two modules can connect to one power supply to create a stereo system.
The modules will support both fully balanced and unbalanced connections. The gain will be ~19dB (balanced) and ~25db (unbalanced). The unbalanced connection has 6dB more gain because it will be converted to a balanced connection.
I am expecting the switching frequency to be in the 750kHz to 1.2MHz range. This will be determined by final tuning/testing.
All connections use headers and terminal blocks so that no soldering will be required.
The purpose of this post is to gauge interest to see how many here would be interested in purchasing these modules when they are completed in about 2-3 months. I expect the price of the final modules to be around $500 per module, those who do a group by for the initial builds will get at least a 20% discount.
The are multiple users here who have my BOSC/Stakrimson modules
I had to make the board 4.85 by 3.75 inches to add some additional circuity, due to feedback that I received for the other board.
Added LED to indicate over current
Added LED to indicate overvoltage
Added LED to indicate that board is powered up
Still need to do final checks before manufacturing the boards. However, the layout is at a good point to start getting quotes. So please let me know if you would be interested in getting one or two of these.
The board will need the following power supplies:
+/-36 to 42.5V for power stages
+9 to +15V for Driver (referenced to -36V)
+/- 12 to 22V for analog sections
A single Hypex / SMPS1200A100 provides all of the required power supplies. and can power two modules to make a stereo system.
In simulations, this amplifier achieves over 98.5% efficiency at 500W.
Update 01/10/2021:
Updated specifications list:
Gain (balanced input): 19.3dB
Gain (single-ended input): 25.3dB
Power output into 8Ω/4Ω: 250W/500W
Input Impedance balanced/single-ended: 44k/22k
Sensitivity (balanced input): 5Vin for 250W into 8Ω
Sensitivity (single-ended input): 2.5Vin for 250W into 8Ω
Size: 4.85" (123.2mm) x 3.75" (95.3mm) x 1.45" (36.8mm)
6 x 4-40 mounting holes
Required Power Supplies for Module
+/-36V (+/-30 to 42.5V) - Amplifier Power Rails
+15V (9 to 16V) - Mosfet Driver Supply - Referenced to -36V rail - 100mA minimum
+/-12V (+/-10 to 22V) - Analog Supplies - 100mA per supply minimum.
I don't know how it is in other countries, but in the US the younger generation has not learned how to speak properly.
The worst offender is "Me and my friend" instead of "My friend and I".
That one drives me nuts and I have been known to correct people when they say it.
The other big offender is "I'm like", or sometime just "like", being inserted repeatedly and unnecessarily into the conversation.
I think that these and some other improper language habits are a problem mostly with people under 40 or so.
I'd like to see some way to put an end to it, but I'm like thinking it is just going to get worse.
I'm trying to fix a B&O CD player that uses the Philips CDM2/10 mechanism.
I had got it nearly working perfectly but some CDs still didn't play correctly as if the error correction wasn't working correctly. I took it apart again and lubricated the radial arm, again, and also cleaned the motor windings which looked very tarnished. When I put it back together and ran the test mode, it wouldn't pass any of the tests. Not even the one that confirmed the ribbon cable from laser to servo board was connected correctly. It had always passed this test.
After investigation I found the power supply lead from the decoder board to the servo board was incorrect once plugged into the servo board. But, only when plugged in.
The decoder provides power through a lead with a 5 pin plug at each end. The pins should be;
This is what comes from the decoder board when measured on the board itself and I also get those readings when measured at the 5 pin connector before connecting it to the servo board. But, and this is what my problem is, when I connect the plug to the servo board and take a reading direct from the plug, the -9.5v becomes +6v. All other pins read correct. The decoder board is still giving -9.5v as it should do.
The 6v then goes to places the -9.5v should go, i.e. it doesn't lose any significant voltage on its journey around the board.
The problem exists if the servo board is connected to the CDM2/10 module or not.
What's happening? If the voltage changed from -9.5v to 6v somewhere on the servo board I'd be checking all components it goes through. But, at the plug before it even gets starts on its journey through the board?
I am a beginner to speaker design and wanted to study designing a DSP-based 3 way crossover in VituixCAD. I have selected the drivers for this project (since I have these drivers with me) as
1) Satori WO24P-8 for Woofer
2) SB15CAC30-8 for midrange
3) SB26CDC-C004 as the tweeter
Since this is more of an academic exercise for now to study the compatibility of drivers and to help me in building a cabinet with some confidence regarding driver locations on the baffle and the overall response, I have generated the crossover configuration based on traced SPLs of these drivers from their datasheets (I know that the recommended approach is to put the drivers in the cabinet and then take measurements and then design crossover based on it).
The simulations that I have attached along with this post have these drivers placed on a baffle of width 32cm and height 105 cm (with 20mm edge rounding for easing diffraction-related anomalies), currently, with driver centered at locations mentioned in the crossover image.
(For more details, the woofer is assumed to be put in sealed box of size 55L, midrange also in a sealed enclosure of about 12 L).
With my limited knowledge, I have tried to design a DSP-based crossover for this system as shown in the first attached image. The vituixCAD six pack showing resultant system response details is attached as the 2nd image. The 3rd image shows the veritical directivity polar plot for this crossover. The 4th image shows the same crossover with mid driver inverted. This was done just to see how good the overall phase tracking of drivers were in the crossover region.
The approach that I took in this iteration of the design was to try to linearize the response of the drivers in their passband as much as I could with parametric EQ and try to level match drivers based on woofer response. Then I crossed over all 3 drivers with 4th order Linkwitz-Riley (LR) filters at frequencies such that the phases of the crossed over drivers track each other till (approximately) an octave above and an octave below the crossover point. (From my limited knowledge I have also included a capacitor in the tweeter branch of the crossover for tweeter protection) Again, since this is not using measured phases of the drivers in the cabinet, I am assuming the phase responses that are shown are the minimum phase responses derived based on the magnitude responses, as calculated by VituixCAD.
I would like to know more details about how should I look at the driver phase matching, can I get better directivity curve and power response curve for this system (since I see a slight 'S' curve around 3.5 kHz in the directivity plot on the left hand side middle plot of 2nd image and slightly rising power response around the same point in the same plot can be adjusted.), etc and in general any advice to better the performance is welcome. I would also like to know if we reduce the baffle support for radiation from these kind of flat flanged tweeters by usinng deep Avalon acoustic like chamfers (shown in attached image 5), will it help in better directivity matching (at least to some extent) between tweeter and midrange driver. It will also supposedly push the baffle diffraction anomalies in tweeter response to much higher frequency ranges which may be smoothed by using felt pads on the baffle around tweeter etc, if required.
Looking forward to learn more from your valuable opinions.
Edits: In the last 3 years, I have made a few 2-way, 2.5-way, and 3-way speakers configurations, thanks to the generous help & knowledge sharing by the the forum members. I have learnt more than I had ever hoped in this journey.. 🙂
It is probably time to do whatever little I can do to organize the information in this (now) long thread.
The below list captures the projects explored in the different speaker projects explored in this thread. I will update with relevant links in due course.
1) The original 3-way speaker design study using the Satori WO24P woofers, SB15CAC30-8 mid, and SB26CDC tweeter on augerpro waveguide
2)
3)
4)
5)
Hi everyone, recently bought these speakers in nice condition and curious about opinion of others who had an opportunity to listen to them.
Specifically interested in:
-are they easy or hard to drive
-amp matching experiences
-comparison with other speakers
-trebles extension “airiness”
-possible tweeter deterioration (is it ferrofluid based?)
-possible crossover upgrade, where to get the schematics if yes
I finally managed to close the projects of my “WOTS LeGrand” and “WOTS Tre” line pre-amplifiers.
Two very well-functioning pre-amplifiers, necessary for the optimal definition of the sound, before sending it to the power amps. Or two useless and boring post-amplifiers, according to the opinion of some of the readers.
Both are dual-mono builds and have the same warm and precise sound, even if they use different technologies: the LeGrand is hybrid (tube/transistor), and the Tre is completely solid state.
The electronic part uses symmetrically designed double-sided PCBs, a single PCB design serves both left/right channels depending on which side is used.
Since they have no loop feedback, good-quality components must be used.
I want to express my thanks to:
JLCPCB for the excellent service in the realization of PCBs;
There have been many questions asked about oscillation in tube amps. These have been scattered across so many different threads that the search engine can't find them all. I am starting this thread to collect the thoughts in one place.
I am doing this because I was searching for something else last week and I found an old thread where someone had asked me how I check for oscillation. I realized that I never saw that question so I posted the answer, but the original poster may have not seen it since the question was buried in a non related thread.
Now I am working on some new circuits and I captured an oscillitory gremlin hiding in my amp. It is the evil hard to catch kind. I have not found the cause yet, and with my current work schedule, it might take a couple of weeks.
I am copying the original questions and answers in the next post.
Full Gabster TD-1 kit: PCBs, all parts according to BOM and an original TDA1541A chip.
It is a 100% complete BOM—Gabster provides a Shared Project access code that you type into Mouser, and all the parts get added to the basket. That is how I bought the parts. Everything is packed safely and securely as Mouser delivers it. The PCBs are fresh; I have not soldered anything yet.
This pair is a unique version with plastic terminal boards. They were usually made with brittle Pertinax boards, which were a real risk when shipping them as they could break easily. This is OEM stuff made for Deutsche Post. They are fantastic in an audio output stage from a DAC, measuring flat in the audio band.
They are in perfect condition, unused. I only connected them to check if they work correctly.
I have a PM-7200 which doesn't power on. Using a working PM-7200, I've narrowed the problem to the front control panel which contains a Toshiba TMP87PH46N IC. One of its jobs is to fire the relay on the AC inlet and I suspect the chip itself is at fault but will confirm this with testing for 5vdc in.
I contacted Marantz's official parts supplier, Sontec but they say the Toshiba is no longer available. I can source the chip on eBay put I presume as a P-ROM, i'll only be buying a blank chip, without the necessary instructions for the PM-7200?
Can anyone shed light on where I could pick up one up?
Hallo,
I build these two 555-based 12V to HV.
Here the scheme and results.
Added a parallel cap to C4 to reach 33uF.
17.5V to 420V (decreasing of 1V each second since the coil and the IRF740 get warm, hot).
Smell of electronic stuff at high temp.
To avoid fail I just did 1 minute of test.
Added a parallel cap to C4 to reach 33uF.
17.5V to 350V (decreasing of 1V each second since the coil and the IRF740 get warm, hot).
Smell of electronic stuff at high temp.
To avoid fail I just did 1 minute of test.
I just connected multimeter at the output to measure the voltage (load).
What can I do to improve thermal stability and reliability? The coil and the irf get really hot.
I plan to put a heatsink on the irf. But about the coil? Is 3A rated. The design suggest 2.1A coil.
Someone stated that 120uH coil would be a solution.
Im not so skilled and no component at hand to understand or try.
My plan is to achieve a stable 400ish DC voltage to power 4x 12AX7 (6mA?)
I have good results with Subwoofer corner placement.
But this can be room dependent.
It seems to me that the corner helps the bad efficiency of Subwoofers as it gives you theoretically +9db in relation to placements away from room boundaries.
What is your experience?
Is corner placement only a help for small subs or do profit also bigger ones?
Based on tips from Papa, and using IXYS Hockey Pucks let's see your F4 Beast builds (might come up with a better name later). It's up to you to decide what to use for the 2 gain stage front end circuit.
The aim here is to have fun building (not necessarily cloning down to the last detail).
Suggested hockey pucks so far, are as follows (probably add a couple more later):
P Channel
IXTN40P50P (Out of 5 measured for transconductance, averaging around 6.8S at 2A and 52C measured at the interface of the heatsink and edge of hockey puck)
IXTN90P20P
IXTN32P60P
N Channel
IXFN48N60P (Out of 5 measured for transconductance, averaging around 6.4S (same conditions as above))
IXFN44N80P Patrick's suggestion
IXFN40N90P needtubes suggestion
I don't think there is a right answer to what is best, it depends what you want to achieve.
They are all in the ball park. No bbq stopper here.
I have measured up 48N60P and 40P50P and they appear to be a nice match.
As to biasing, you can do it the regular way, or you can just use a big sink
and adjust the value until it settles into where you want it - just takes a
little longer warm-up time.
In any case, the drift of Ids against temperature is quantifiable and can be
easily handled without degeneration if you have adequate sinking and are
willing to do lengthy adjustment and put up with longer warm-up times.
Just things that DIYers are good at and commercial manufacturers are not.
Hi, I have a Mark Levinson 31.5 cd transport which works well for a while and then appears on the display: SERVO RESET. the reader does not obey to stop or change the track, it has to be turned off completely. Has anyone had a similar situation that could repair it? Thank you very much.
Hi Guys
A couple of years ago I built a kitset valve (tube) amplifier from Tubedepot, and fitted it in a restored a 1930s Philco radio case. It's in my workshop, so I can listen to music and podcasts while I fix my cars.
Further back, my grandfather taught me to solder when I was about ten. An early lesson was to be very careful soldering when wearing shorts! Granddad was a telephone technician who designed and built things like an AM/SW valve radio, which my brother (a modern-day radio tech) has recently restored. I've been playing with auto-electrics and simple electronics ever since, and building that Tubedepot kitset amplifier reminded me of hours spent soldering at my grandparents' dining table. I was hooked.
So, when my computer's Bose speakers died a few months ago ("Can't fix that mate") I didn't just buy another off-the-shelf speaker setup. I bought an Elekit TU-8185 mini-amplifier and spent a few really enjoyable hours with a soldering iron. Again, the amplifier and onboard DAC worked as soon as I turned it on, and no smoke came out. I've added a pair of speakers - they took far longer to build than the amplifier - and the result sounds and looks fantastic. I doubt that the sound is measurably better than the Bose system, but for listening to music while I work, or Youtube videos, it's as good as I hoped. And it's nice to know that if the Elekit ever needs fixing, I have the circuit diagram and a list of test voltages.
The thing is, building stuff is addictive (as I'm sure most of you have already discovered). Now that I've finished building my desktop amp and speakers, I want another challenge. Elekit's TU-8900 looks like a fun next step, so I've started buying a few bits like valves, timber and speakers. I'm sure I'll have questions!
My Granddad's multimeter. If you couldn't buy something in the thirties and Forties, you built it.
They most definitely don't make them like this anymore.
The Philco case I restored.
The Tubedepot amplifier kit, with orange drops for added orangeness.
The blue glow was unexpected but apparently normal.
The baby Elekit. I made the knob on my lathe to practice machining tapers.
And the computer speakers, made in Blackheart Sassafras.
There was a very nice little Class AB amplifier I worked on years ago based off of Apex Audio's wonderful little FX-8 lateral FET amp. Back then I did not want to use the lateral FETs because they were pricey. So I set off to make a hexFET based version. It was called the FH9, and it sounded very good. If one used generic resistors and caps, you could build the whole amp for under $10. The layout was done by several people, Sonal K and Prasi, but the one that caught on was the Sonal K layout.
Here was the Sonal K layout:
Many people have built this amp since then and it has been a favorite. At one point, I swapped out the transistors for some high voltage ones and hooked it up to a $20 Abletec +/52v SMPS. Running a pair of IRFP240/9240's I was able to eek 150w into 8ohms with it.
That's 34.5Vrms into fan cooled 8ohm load:
Over the years, I continually get requests for help with this amp or people asking for a PCB etc. I have noticed that lately with the Covid19 quarantine going on, many people are not having as much cash on hand for premium parts. So I thought it might be neat to revisit this amp and see if we can make a nice performing budget 100w amplifier. Naturally, I have enlisted the help of JPS64 to do the layout, and Vunce to help with the beta testing. Vunce has since gotten the original FH9 to work and is about to get stereo sound any minute now. In the meantime, I have put the circuit back on LTspice (it was on Tina in the early days). And I have tweaked it for 52v rails and nominal output up to 100w into 8ohms. No fancy parts and not even four MOSFETs. Just 1 pair per amp if you use Fairchild with a higher power rating, should be fine. No matching to do. The amp is super simple and very pleasant to build in one evening. If you happen to have an old Abletec 225w SMPS, dust it off and you can have one of these amps playing. It has a very powerful bass and nice overall presentation. One of my favorite simple amps to make and listen to. Many people can vouch for its sound if you check on the Apex thread.
On this amp, one can use nice Dale resistors, boutique input coupling caps, or you can use no name Aliexpress resistors - it won't matter. I just ask that you get either genuine Vishay IRFP240/9240 or genuine Fairchild FQA40N25/FQA36P15's (about $7/pair). You can run it at +/-35v of course as a 50w amp, but I suggest going for the +/-52v version and getting it to crank to 100w without a sweat. THD predicted at 100w is only 0.005% and at 25w is less than 0.003%. Dominant second/third order harmonic distortion, and a semi-monotonic descending higher orders (ok, so it's no SE Class A amp in profile...) But what it has is some great bass dynamics, and killer foot tapping immediacy. A very fun amp to listen to and play with. Cheap fun.
If you don't want to go with a cheap +/-52v SMPS, a single 300VA 38v trafo will work nicely or dual 200VA 38v trafos and a simple CRC PSU with four 10,000uF caps each will work fine.
Here is the LTspice schematic (in JPS64 part notation):
Here is a sneak preview at the 100mm x 100mm PCB that JPS64 is working on. We will have optional flying leads with quick connects for the MOSFETs.
The pre-proto FH9HVX built by Vunce is working very nicely. Here it is in an old donated chassis and powered by the Abletec SMPS. There is not much to this amp. But it packs a punch.
I want to use this extractor https://www.tendak.com/collections/...converter-for-hdtv-soundbar-speaker-amplifier
to get me digital coax audio into an external dsp. But in the description of the device it is mentioned that TV volume control cannot be used with this extractor device with HDMI ARC connection between TV and device. Why is that?
In my understanding, the TV controls volume in case of PCM or LPCM stream and outputs the stream on HDMI ARC. Why cant TV volume control not work with the said extractor device?
It works down to +/-2.0V.
Distortion is low and current consumption is only like 3-4mA depending on the status of the batteries.
Has been tested in simulation with 32ohm and 300ohm load.
I challenge everybody to try to design a real lowpower headphone amp for +/-2.0V.
Post your schematic here.
Hey guys,
Actually, I've been keeping an eye on D&D 8C active monitor speaker for a while now and after Erin's Audio corner YT review, I'm tempted to try my luck designing a similar active speaker to see what would come up at the end.
I have access to many sample drivers so it's needless to buy drivers in the first place. I'll use Hypex DLCP with some Ncore NC252MP (rated 250watts@4ohms). I have also miniDSP 4x10HD if needed. For now, my biggest concern is about maintaining a controlled cardioid pattern from about 100hz give or take for the midbass/midrange driver. I'll use one or two subwoofers at the rear side as boundary coupled bass drivers just like 8C. I have also some options for a tweeter that I think will be of lower significance for now. I'll take care of that later.
It will be a big profile bookshelf type of speaker, not a floorstanding.
Hary F. Olson has an article "Gradient speakers" AES Volume 21 Issue 1; January 1973 I'm sure I had downloaded it many years ago but can't find it on my laptop and I have no active membership for now. If anybody has access to this article I would be grateful to have it. It would be much of help to read that article.
For now, I'm thinking about some drivers. for subwoofers, I'm considering SEAS L26RO4Y. I don't know one or two. I'm gonna have two on the prototype enclosure so I can test both ways. I have no smaller than a 10" driver for this region. for the midbass/midrange region I have a couple of choices. this is the most critical driver within others. Due to gradient cancellation, it will have about 6dBs lower SPL so a high dynamic and high excursion driver is more suited to have the same acoustic output after the cancellation. A driver with resonance frequency close to the lowest midbass frequency will be needed and I may have to use some EQ to boost lowers frequencies to have a flat response around 100hz.
I've never design anything with a flow resistor port to get a passive cardioid pattern. I'm gonna use polyester felt, natural ship wool or Ecco felt, I don't know for now. I have not much idea about the port itself. I have to figure a way out to measure the delay needed for phase cancellation. I think it could be measurable by the impulsive response in the time domain but I have no idea about the size of the port and the ratio between it and the SD of the back of the diaphragm.
Faital Pro 8PR200 and 10PR410 are my first choices. High excursion and good dynamic range. there are a pair of SEAS U22REX/P-SL also available. I have also Beyma 12P80ND but I think that would be oversize for the project. for the tweeter, I'm considering Beyma TPL-150/200H or Aurum Cantus G1 or AST25120 or maybe a BlieSMa T34B with a waveguide. I have a 3D printer at hand and can print a waveguide for the dome if needed.
that's it for now. I will make my mind and any idea is much appreciated. I'm totally new to this kind of speaker design so I like to hear opinions. I hope in the end it will be a good project with justified and measured results so anyone interested could build it as a DIY.
I've purchased several of the B&O ICEPower 125ASX2's. The bass is astoundingly granite solid, but the rest of the range wasn't as good as my Hypex amps on my Quad ESL63's. This weekend I decided to put my ears away and strap on my engineering hat and try to understand the differences between my three switching amps (tripath, ICEPower, and Hypex)
I started by inputting a logarithmic sweep into each amp and measuring the output across a 7.5ohm wirewound resistor and measuring the output. I then calculate the difference between the input and output. After I have that "baseline", I then replace the resistor with the Quad ESL63 (which is a nasty reactive load) and repeat the measurement. This was my zero order starting point before I started looking at distortion spectra.
One of the differences in these switching amps is that some change their response with the changes in load (Tripath, I'm looking at you).
Anyway, I saw something horrifying with the ICEPower amp, the treble was rolled off significantly, as you can see in amplifier frequency response graph below.
I've added a potentiometer at the input of the amplifier, and it turns out that the input impedance of these ICEPower amps drops significantly with rising frequency. At DC, the input impedance is 270K, at low frequencies, it drops to about 27K, and at 20KHz it's below 6K. This means that the amp needs a low output impedance source to drive it The beauty of these amps as I saw it was that they were complete with only connectors and an enclosure needed. But it turns out that a simple volume potentiometer put in front of the amp messes up the frequency response significantly.
As seen below in the input schematic, there is an anti-aliasing filter, I unsoldered the grain of salt sized capacitors and the input impedance got much more stable. The input impedance graph on the left shows the input impedance with and without this filter.
I'm building an Op-Amp buffer stage to go between the potentiometer and the amplifier input. The op-amp stage will be powered from the auxilary output of the amp itself.
Keep this "feature" in mind when you consider this design.
My name is Gesualdo, and I’m excited to finally join the diyAudio community
I've always had a passion for electronics. Although I’m a qualified electronics technician, I’ve never worked in the field professionally. My knowledge is therefore somewhat limited, but I’ve always managed to get by thanks to curiosity and enthusiasm.
I’m particularly interested in analog audio and amplifiers. In recent years, I’ve repaired a few solid-state amps, but I’ve never had the chance to work on tube amplifiers. I’d really love to hear how they sound in person!
So far, I haven’t tried working on tube amps mainly because I still feel I have a lot to learn. But I hope to grow here with you—by reading, learning, asking questions, and maybe one day building something of my own.
TL;DR: A friend and I are developing a DSP amp and are seeking feedback on our proof of concept.
Note to admins: This post is not intended for commercial purposes. I have deliberately avoided advertising any brand or product names. The sole purpose is to gather feedback for our feasibility study on a project that may potentially become commercial in the future.
Dear fellow engineers and enthusiasts,
This is a prototype of our audio amplifier, which is based on the ADAU1452 DSP and two TAS3251 chips in the output stage. This setup provides a total output of 4x175W (or 2x350W) at 36VDC.
After several months of development, we now face some critical decisions, the most important being the viability of this device for mass production and the potential features to add or remove since this proof of concept.
This version is not the final iteration; we are still optimizing certain parameters. Most notably, the THD+N currently measures at 0.08% at 100W into 4Ohm and 0.008% at 10W into 4Ohm, with an A-weighted noise floor around 105uV. While these numbers are quite good, they do not fully match the TAS3251 datasheet. We are continuing to optimize the PCB layout, LC filter components, and PFFB.
We aim to provide plug-and-play functionality for this device, meaning users will not need to tweak the ADAU DSP and can select one of the pre-made use cases that are easily configurable and controlled via a user interface. For more advanced users, full access to the ADAU DSP will be available using SigmaStudio.
The main firmware, based on FreeRTOS, runs on an STM32F4 MCU. This MCU initializes and controls the DSP and amp chips, among other functionalities on the board. The audio signal path is also managed through the MCU, allowing for various measurements such as level metering and FFT. Additionally, the MCU handles USB audio input and the user interface.
We are also considering integrating 3rd party module to significantly enhance connectivity and streaming capabilities.
Our current focus is to prepare the hardware fully, so all new features can be added or enabled simply by updating the firmware in the future.
Please share your thoughts on how appealing this project is to you and what features you would like to see added or removed. Your feedback will be invaluable in guiding our next decisions. Below is a detailed list of features.
Thank you!
Notable features:
Inputs:
I2S
SPDIF
Bluetooth with aptX
USB audio class
User interface:
GPIO and Rotary encoders
All features controllable over I2C registers and through SCPI interface on UART
Few RGB LEDs on board
Powering:
36VDC up to max power
USB-PD up to 100W (up to 240W in the future once the technology becomes available)
Connectivity:
Point-to-point stereo link with another module using CC8520
Integration with third-party module for streaming services such as Spotify, Apple Music, Amazon Music, Tidal, Deezer, Qobuz, TuneIn, and more...
Upgradability:
Main firmware upgradable over USB
USBi interface emulated by main firmware, allowing real-time DSP tuning and debugging without a dedicated hardware programmer
I've had a bunch of the goodies from Ian's latest and greatest Group Buy on hand for a bit over a week now, with various combinations making music since this last Monday. NONE of it is broken in yet and I have a LOT of combinations and variations to try still... so no impressions to post YET.
BUT I'm starting this thread as a way to gather impressions and info about his GB RPi goodies... the FiFoPi, various DACs and I/V / output stages along with the ESS DAC controller, the LiFePO4 supply, the updated IsolatorPi, and a bunch of supporting accessories.
Anyone got any sonic impressions or tips they'd like to share.
Me, I'd like to get through a few more of the permutations I'm planning to try before starting to share how they work. PLUS I still have bits and pieces arriving... LL1544a's AND LKS discrete opamps both delivered today. A few more orders are yet outstanding. AND a few more to get in.
I'll update at some point what I've got and what I'm trying.
In the meantime, post away!
Greg in Mississippi
P.S. Anyone got any good alternative clocks worth trying? I have 22/24 & 45/49 Crysteks AND various NDK's... 22/24 & 45/49 SDAs, selected 90/98's from Acko, and a TON of standard SDs. Anyone got a good source for high-grade Connor-Winfield's or other possible alternatives?
So I am trying to build my first speakers, and I got stuck (obviously) with no idea why predicted crossover and real implementation is way out of acceptable range?
I will attach program I've used and response graph and photo ,of loose and glued implementation. I do hope for help. Thanks in advance
Hello, I'm a new member in this forum and I'm really interested in building my first kit speaker. Since I'm very unsure about whether I should get this one, I'm curious about opinions and thought this forum might have the most members with opinions about it. I just started this DIY journey and am learning about parts, drivers, crossovers etc and want to learn about what components might improve the overall performance.
Hi does Anybody has info about this Amp , looking i found is kind similar to Polk d4000.4 and Precision power p900.4
Power Supply fets : IRF3205
Output controlled by IRS2092s per channel.
Other tecguy touches the regulators to220 (7812,7815,7915) dont put it back in the right places .
This Amp came in protection , shorted outputs , pullout shorted components still in protect.
DOes anybody got info about this type amp or any schematics .
Lot of thanks .
I currently have these in a pair of Pensil cabs but don't have the room to keep them.
What small cabs would get the most out of these drivers?
Minionken?
I've also read about the Golden Ratio cabs?
I like bass extention so what would be your recommendation for a small cabinet to get the most out of these drivers?
A friend of me want to buy one of both, but he is unsure, which of both should he prefer.
Maybe anybody have heard both at the same time on a listening test.
I can imagine that both devices have excellent sonic character. But maybe the Ultra Analog D20400a sounds more musical.
Thank you for advices.
