I have two 0.82R 25W power resistors at 3.25A dropping the DC voltage on my 211 heater circuit. They are heat sink type power resistors and bolted to a large 15mm Aluminium plate - see pictures. The whole plate and the Oil filled choke on top of the plate gets to 55 Deg C in a warm day (output transformers on this plate too)- will this be ok for long term durability of the choke and could there be any negative (or positive) impact of this heat on Sound quality.

If it makes any useful difference I have a few ideas but wondered if it's all absolutely fine like this (it has been so far but the summer it seems to get more of a perceived concern)?

Thanks,

Dear All,

With this message I would like to announce the release of SoundEasy version 28.

Firstly, many thanks to you, the Users, who contributed to maintaining the list of new features, suggestions and bug reporting. As you will see in the List of Improvements in V28, your input has been guiding this release to quite significant extent.

As with all previous releases, I would encourage you to review the List of Improvements to see if there is anything you may see helpful in your design activities.

There are two items in V28, that may be of significant interest to you: (1) Automatic Extraction of Minimum-Phase response from measurements, and (2) Automatic ANSI-CTA-2034 tests with an external turntable.

For complete list of the new features, please visit my website – thank you.
https://www.bodziosoftware.com.au/

Excellent presentation from Sean Olive:

“Sean Olive on Predicting Loudspeaker Sound Quality and Listener Preference”
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Senior loudspeaker designers may be interested in the optimization of loudspeaker system response based on ANSI-CTA-2034 measurements. For this to happen, you will need to take the ANSI measurements for each driver in your system individually, and the use these data in CAD/Optimization process. SE will optimize for user-defined “Listening Window” targets and “Power Response” targets.

The above is easily accomplished with V28. Just run each driver individually for horizontal and vertical SPL curves with 5deg stride with a press of a button. Have a coffee in the meantime. SE control the measurements and the turntable.


You can also run the measurement process manually. The process is simple and described in the manual: https://www.bodziosoftware.com.au/Chapter_16_4.pdf

However, as I understand, people are using automated measurement processes, because they want to avoid doing this manually.

ANSI-CTA-2034 is here to stay. The concept links measurement data with listener's preferences, and is fully explained by Sean Olive in his papers. But, the standard requires very large amount of spatial data to be collected. I am sure, you know how mundane and error-prone is the manual process.

Hence the turntable: https://augene.blogspot.com/2022/03/new-turntable-for-loudspeaker.html


Best Regards,
Bohdan

I want to build a box for A11MS .. My requirements are that they should sound as revealed as they can.Soundstage 2D and 3D are important to me.

Can you help me find a box that can handle this?
I'm happy if they can go down to F3 50hz.
Thanks for all the suggestions you can give me.

Have 4 tripath Ta0103a chips and one Ta0105a chip for sale
These are chips only. Got them at an auction from a closed
repair shop. Items are new and have never been used.
35.00 ea.

KJF

I have a pair of Dayton Audio ND65-8 2-1/2" full range drivers that need enclosures. Top priority is sound quality, then size, then SPL.

I began by plugging the driver into Hornresp but have had a hell of a time getting the line reasonable flat above 600Hz without adding a ton a stuffing. Looking for alternate enclosure types or suggestions on modifications to make to the existing model to achieve a flat response curve without so much dense filler.

Looking into exploring open baffle subs with existing 18" Faitals, in an active system. I have a couple 12" sealed servo subs playing the lowest end so don't necessarily need the OB subs to get to 20Hz. I envision having the four subs playing the lower end and the OB subs playing alone above 50 or 60Hz up to 100 or 120Hz.

I'm thinking H or U shaped. Pros & cons or recommendations?

I understand the cavity behind the U or in half the H shouldn't be too long to avoid resonances. How shallow is enough? If I use a 24"x24" baffle should I keep it under 50% wing, so 12" for the U or 6" each way for the H?

How do I model an H baffle on Basta or Edge? 24" from driver center to baffle edge, plus 6" wing one way, plus another 6" for the sound to come around the back of the wing and meet halfway, so 36"x2=72" baffle?

I ran a couple of searches in this forum thinking others would have posted o something along these lines before, but didn't get much. If you are aware of another thread where this was addressed, I'd be happy to get the link and read up.

Thank you!

Hello everyone, i just finished my preamp project and wanted to share it with diyAudio community.
Here are some tips for the circuit:
1- Use the preamp with high impedance loads.
2- You can change the gain by changing the values of R2 and R3.
3- Change the gain depend on input signal.

The PVR 6MR500-NDY is one of my favorite high sensitivity mid drivers, but the logo on the dust cap is UGLY. So I took a chance and did some cosmetic surgery...

It's hard to tell what was originally there but you can still see a faint shadow of the logo left behind under brighter ambient lighting. Its definitely better looking now and it didn't hurt the dust cap material at all.

I used 2000 grit sand paper and some coarse pre treatment of cotton swabs dampened with carburetor cleaner spray (nasty, smelly stuff !!!).

Wiping the logo with carburetor cleaner soaked swabs removes the bulk of what appears silk screaned paint. When the cleaner residue has completely evaporated, I sanded with very light pressure in a circular pattern, alternating directions back and forth.

If you guys use any other methods to do this, please let me know if they're more successful. I love these drivers but they are so ugly with that stupid logo. I wish PRV would not put them on to begin with.

I bought a Well Tempered Record Player with a missing motor. Table arriving later this week. The platter should be close to 292mm diameter. Not sue of the hole diameter in the plinth as yet. Anyone have suggestions on a replacement? Anyone got a spare?

Hello , my first post on this forum. If anyone thinks there is a more suitable forum please let me know.
I am trying to repair a BOSS BR-1600 mixer / recorder which has 2 defective input sockets. They are 6.35mm
pcb mount sockets and I have attached 3 pictures. I am struggling to find suitable replacement parts that have correct
number of pins ( 4) with correct alignment to fit the PCB. I have looked on all my usual parts sites without success. I have found a supplier in the US
which has the parts for $7 each but the only way they will post is via a tracked system which will cost $57! OUCH.
So I am looking for a UK supplier of a suitable part. Cannot see any manufacturers name on the sockets.
If anyone has done a similar repair or knows a UK source for this part please let me know.

I'm in the process of having a Sansui 1000A Tube Receiver recapped and it turns out the right audio output transformer is bad. My receiver is an earlier unit with the transformer containing "Sansui" in block writing along with the numbers 410-5234B. Much of my audio equipment has sat in storage while I was stationed overseas and lack of use has taken its toll on the electronic components. Please message if you've got a spare operational Sansui output transformer for this unit.

Tube amp this ancient art, it has been no shortage of youthful beauty. Even youth, but also can not afford to leave the old imprint Free, antiquated model, uniform shape, rigid material, long-lasting tools with .................. .. Recently made a new tube amp, post-modern art blend components, or may in the future to stay a little tube amp enthusiasts ideas.

Today I have a pair of DIY 2-way bookshelfers + 2 x SVS SB1000.

The bookshelf speakers feature a SEAS W18EX001 for bass/mid and Satori TW29B-B tweeters in a vented enclosure.

My next project is making the system higher WAF, while expanding to a 3/4-way setup.

It’s an active setup and I have a miniDSP DDRC-88D.

I need input on what I need to do going forward, so I’ll lay out my current questions/thoughts/plan.



The “increase WAF” part of the project involves building new A/V furniture (DIY). As a part of this I’ll build two cabinets that can house the SVS subs + 8” woofers for bass/mid-bass.




In the end I’m go play around with the X-overs ofcourse, but I imagine something like 60/800/1600 hz (sub/bass/mid).

None of the above might be ideal, but it’s a question of improving SQ and increase WAF, with what I’ve got at hand.

This is the power supply from a Modwright SWL-9.0se. Dan sent me an upgraded one and I replaced it myself, so I was able to keep the remaining parts. The PSU was removed 100% in working condition.

I figured someone could use it for a build.

Heater voltage is 12V
B+ is 325V

The only thing I didn’t include with it was the choke which I had to reuse and the 5ar4.

It includes the attached led and switch.

Ships from Houston, TX to Conus only.

NEW PRICE - $150

How to implement a straight Line CBT array?

Hi All

I am contemplating a small straight line passive CBT array for personal home stereo use. I ve read the Harman patent explaining the straight line passive CBT at https://docs.google.com/viewer?url=...com/pdfs/dbc4f6e813a18db71b87/EP2247120A2.pdf.

The patent provides a brief explanation of the passive component values as quoted below

"The configuration of the stages in FIG. 2 is recognizable to those of ordinary skill in the art to be a low pass filter. While the topology is the same as a low pass filter, the values of the components are radically different. The component values are mistuned. That is, the component values are sized to create flat group delay with frequency, which is not done with low pass filters. The component values are also sized to create relatively flat attenuation over a broad frequency range. As shown in FIG. 5, the first 4 or 5 transfer functions (from the center out) are flat. The group delay along the ladder is cumulative as is seen in FIG. 4."

However, the below is still not clear
a) group delay
b) L and C values
c) What does it mean to say that the LPF is mistuned

I would appreciate if someone can explain how to implement the CBT.

Thanks,
Goldy

I've got 4 Accusonic/Show amps (2 x PSA-3900, 2 x PSA-31500), all four of them were working in all modes (stereo, bridged, parallel/mono). The following day I was testing them out and all of a sudden all four amps only work in bridged mode but not stereo mode or parallel/mono mode. Has anyone ever seen or heard of this before? I'm testing each one on their own so it shouldn't be a power supply/voltage drop issue. The only thing the four of them had in common is that they were all plugged into the same power bar running through a DBX drive rack PA2. So I tried them individually on a different power bar and a different outlet with a direct signal to each amp, bypassing the DRPA2 and still have the same issue. What would cause 4 individual amps to all lose stereo mode at the same time? I have verified the following during my trouble shooting:

• speaker is working: used mutiple working speakers with no luck
• speakon cable is working: wired correctly to pins 1+/1-
• signal is working: balanced signal being sent
• power supply is working: breaker has been reset
• breakers on all amps are all reset
• clip limit is on but i've tried it off as well with no luck
• 30hz filter is off but i've tried it on as well with no luck
• bridged mode: signal showing on both channels when channel A pot is used, as designed. sound is being sent to bridged output channel.
• stereo mode: Signal is showing on both channels A and B. sound is not being sent to output channels A or B.
• parallel(mono) mode: Signal is showing on channel A as designed. sound is not being sent to output channels A or B.

Here's a link to an older version of the amp that had binding posts. my version has 3 speakon terminals only 1 stereo pair and a 3rd for bridged mode. https://www.manualslib.com/download/1536675/Show-Psa-Series.html

pics of front and back attached.



Thanks in advance for any insight or trouble shooting suggestions. I feel like there is a very simple and obvious answer to this but I'm not sure what I'm missing.

How does MA Alpair 10.3 compare with pluvia 11?
Both are of same size and now the price of Alpair 10.3 have dropped and are slightly less than the pluvia 11. But Alpair 10p is at the same cost which is little higher among these.

For background:
I recently purchased a Rotel RB-850 amp and RC-850 preamp on e-bay. While the seller said it “tested” good I expected given its age to be less than without issue. The amp seems okay but the preamp bass tone control was inop, turning the knot was ineffective. I suspect caps in the circuit need replacing. I was using an iPad mini using Apple Music lossless as a source. I was curious as to how it sounded bypassing the preamp.
It sounded nice.
So my question is this, given that Apple provides an equalizer, as does Spotify, is there any advantage to using a preamp if the only source is going to be a tablet or phone? Is there a possible damage to downstream devices eg amp or speakers?
pros cons?

This trafo has 2 main power amp windings, one lower voltage for 4 ohm and one higher for 8 ohm. User selectable by a switch/ relay .

I have this trafo for DIY purposes. Can I use the 2 main outputs (4 wires) at the same time whilst sharing the single centre tap.?.Windings 5, 6, 7 ,8 ,9

I posted this question in my for sale thread, but figured it may get lost there and I dont want to keep bumping it for this thread outcome.

Being remote, i'm trying to get some Toshibas sent off to al2002. Money is in hold by paypal ... scammers, as I havent used the account for accepting for a while and its a significant sale, so they flagged the transaction and are making money on the short term market with our money along with the almost 10% they are making on the transfer ... erm, I mean 'holding it for his/our safety' 😛

but having gone into my local PO, they say they cant do ECI courier express, only standard international express, which isnt really much of an express at this point in covid, so i'm having to do the label and all customs documents at home and buy the print label for my postie to pick up as a favour, or just so its 100% ready for when I can make it into the nearest large PO that does accept courier pickup (Maryborough) on Monday and can skip the queue, meaning my lift doesnt have to hang around while i'm in the PO line. I have no objection. the money gets released when the package is tracked to arrive and no complaint, so we're good in the end.

anyway, being rather time poor at the moment, my question is. can somebody help me out with the correct import tariff # (10 digit I think?) for transistors/electronic components into the USA for the customs declaration? I'm hoping someone can help me out, as the quick google search i've done this afternoon quickly led me down rabbit-hole of government and government affiliated websites, with no clear answer. I figure the hive mind here may be able to help, as many will have been in this position before.

Thanks in advance.

AER compact 60 mobile runs on 12 v (2 6v).
Made in Germany . Charges on Euro system. I would like to replace the battery & charging system to USA system.
I want to replace charger & batteries to a single lithium UTV with it’s designated smart charger.
Any advice ?

I need the circuit diagram or service manual for the Cambridge Audio CP-2 phono stage. Would appreciate a PM if you can help.

Thanks in advance.

SOLD These are the pinnacle of old school Altec builds! Sound way more modern than you would expect.

We just moved into a 100 year old house with smaller rooms and less space for hifi so I am hoping to move to a smaller format monitor. I have lots of trade ideas and am looking for things like:
BW 801 or 802 (ideally S2 or S3)
KEF ls50
PSB Synchrony
SEAS Thor
Harbeth / Rogers monitors
Snell E

Hoping to find something that's a better fit for a smaller room!

These speakers look and sound as good as you're hoping. HIGHLY efficient.
Full 8 ohm load (GPA HF diaphragms), Jeff Markwart crossovers and a pair of GPA crossovers (one GPA has a broken trace, easily jumpered). Altec + Mantaray logos. In excellent condition.
Cabinets were constructed by a master cabinet builder named Dale from St. Charles IL. Oak braced, MDF walls. Internally fully covered with a black insulation that's comparable to what airplanes use in to insulate their cockpits. Cherry veneer with Tung oil finish, it's begun to saturate with UV and looks wonderful.
Nice brass binding posts.
Includes custom made dollies with locking wheels.
Local pickup in Chicago. Not interested in separating the drivers and cabinets. These speakers are surprisingly easy to transport when you remove the woofers and load the cabinets separately. I was able to transport both cabinets in a Toyota Rav 4. (Tight but it fits).

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probably the «Darlington inversé» is the best solution to avoid VAS🙄

hello,

what are the modern incarnations of Jean Hiraga "Le Monstre" published in L'Audiophile n°27 (ancienne série) in Feb. 1983 ?

Any one in this community need a ticket to dead and company in Boulder tonight? I have a field ga miracle for some one in need.

Looking for this connector

Our Roborock S5 stopped working, and in the process of trying to fix it, I destroyed this connector. Does someone know which sort of connector this is, and where I can buy a replacement?

The outer dimension are 12*6*13mm (LWH). The pins come out in a 4x3 pattern. The counterpart is a PCB, with traces, so this is sort of a edge card connector.

many thanks!
Erik

I am looking for a power follower like Andrea Ciuffoli's versions under
http://www.audiodesignguide.com/my/Follower_99c.gif (single ended class A)
http://www.audiodesignguide.com/my/Cool_Follower1.GIF (push-pull complementary)
http://www.audiodesignguide.com/my/Hot_Follower2.GIF (push-pull complementary)
but in a circlotron version with only two transistors (MOSFETs) and a balanced input.

Are such a diy project already started here ?
Thanks for an advice.

P.S.: this threads describes all versions with front end and voltage gain:
https://www.diyaudio.com/community/threads/current-feedback-mosfet-circlotron.345287/
https://blog.audiomaker.tech/pdf/antimatter.pdf
https://www.diyaudio.com/community/...t-circlotron-by-mike-rothacher.130810/page-15
https://www.diyaudio.com/community/threads/vssa-circlotron.261515/
https://www.diyaudio.com/community/threads/circlotron.353301/
https://www.diyaudio.com/community/threads/vssa-circlotron.261515/page-7#post-5789121
https://www.diyaudio.com/community/threads/joe-berrys-circlotron.384070/
https://www.diyaudio.com/community/threads/simple-circlotron.356473/
https://www.diyaudio.com/community/threads/jfet-only-circlotrons-without-negative-feedback.350904/

http://www.audiodesignguide.com/Hybrid2011/index.html
https://www.diyaudio.com/community/threads/d3a-mosfet-hybrid-circlotron.233152/

Hello to everyone,
some months ago one user of this forum suggested me to look at the MONOphono preamplifier illustrated on enjoythemusic.it (click here for the article).

I decided to start building it however I do not clearly focused how to do it specifically regarding the powering.

In the attached schematic is shown that the all the circuit needs 320-350V DC so can someone provide me a solution to power it as an independent unit? Is advisable use a 5Y3 tube? If yes can someone provide a little schematic and tell me where to find a suitable power transformer (I live in Italy, so the power transformer needs to work with 220-230V AC)?

In this first post I will update all important stuff continuously for your convenience
New input interface for ACH-01 and stiffer
carbon fiber support (28 may) post 66 (better!!)
Add stiffnes post 69 (better)
Add "dust cap" stiffener... is it better?? Post 71

Background: After have been experimenting a lot with Servo subwoofers or MFB motional feedback in the 90-ties with success I went to dipole subwoofers and QUAD ESL 63 electrostatics (modified). Everything was fine until I realized that sometimes the ESL 63 playing on their own, had a magic in upper bass that can not be achieved with dynamic woofers... nope nix njet nej ikke.
8-10% distortion in a woofer does not blend well with QUAD or other electrostatics with <1% distortion in bass.

So only way out is to reduce distortion with a factor of TEN ! (Or go back to dynamic speakers..😱 naa.. )
And here is how it is done 😎
Circuit: First I am using ACH-01 accelerometer and using Piratelogic Electronics EVE 2020 circuit boards which is wery convenient, however this circuit is not designed directly to fit ACH-01 so some tweaking on some values has to be done... also using CFB is changing frequency responce and phase a lot and on top of that dipole woofer, the frequency correction and phase response will be TOTALLY different from using the EVE 2020 the "normal way"
Which is to drive voltage amplifiers with Starbass accelerometers and small woofers in small boxes. If you want to do so there is another thread by chriscam on this forum.

So be careful, the manual for using EVE 2020 will not guide you the right way for this combination... but nice and easy.
We will get it working! And if you want to make it more easy use Star bass accelerometer. They seems to work great.

The benefits with MFB CFB and Dipoles: Using motional feedback to a Dipole woofer system is double or maybe triple compared to a closed box!
First: Distortion comes with longer strokes, which you have a lot more with dipoles than any other principle.
Second: Since the dipole compensation 6dB/octave raise the low fundamental tones, those fundamental tones has corresponding harmonics which will be raised several dB! If you play a 100Hz tone, the 2nd harmonic of this tone is also lifted 6dB, and worse... the 9th harmonic 900Hz will be lifted >18dB!!
Third: The 9th harmonic 900Hz is much more disturbing and noticeable since your ears are much more sensitive in those frequencies.
Dipole woofers are hard to integrate with low distortion midbass of an electrostatic speaker!
Reed the theory papers below and in nr 3, you find the benefits of combining CFB and MFB.

Distortion reduction and measurements part 1: Post 30 shows 2-3 times lower distortion, but it will be improved!
I have reached a more than ten fold reduction in distortion or 22dB in a prototype, and here i will guide you trough the building, schematics, measurements setup and all problems that you may face during the journey, I know, I have done all mistakes there is, and will try to cover them all.

SERVO subwoofers or MFB theory:

1. http://rmsacoustics.nl/papers/whitepaperMFBtheory.pdf
2. http://rmsacoustics.nl/papers/whitepaperMFBdesign.pdf
3. https://www.rmsacoustics.nl/papers/Impulse Compensated Driver setup.pdf


Input stage: The black and white part of the schematic is the accelerometer itself and the buffer J310 68k and 820 ohm resistors, mounted on the woofer, these are SMD components glued to the cone and hard wired under a microscope... crazy idea from the beginning, and even more stupid when the J310 was fried :-(
A part of the schematic EVE 2020.0 is shown, and a table with some assumptions. With ACH-01 you should add an impedance buffer see below.. (Starbass has a buffer already built in)

Updated 220511
Accelerometer gain stage and loop mixer: Post 4 is misleading regarding J310 FET.. see picture below.
I have seen the application note schematic for ACH 01, but was mislead by another users design.
The ACH 01 shall have a negative bias as shown on the application note, to minimize distortion.
I will do a last try with ACH-01 Otherwise I buy ClingOn from Chris, and just get it working...
Big thanks to Robert-H Munnig Schmidt at RMS acoustics for explanation!! 🏆
Rob has achieved 30dB loop gain and 45deg phase margin... is that a world record? (some people is impressed by Messi and Ronaldo....)

Stability, Phase margin, and OLTF measurements: Post 34
Stability at low frequency is achieved but at around 3kHz it looks really messy. So I am reaching out for any help, here.

Below is the input side of the accelerometer on EVE 2020 board. From here you will see that everything has to be made different with Dipoles.

How it should look like!

I did a last try with ACH-01, with stiffer carbon fiber support and new electric interface in post 66 and it works much better!

I am looking for a pair of Aleph J PCB’s. They are not in the store for 2 or 3 months so I am hoping someone in the UK had a pair. If not I might have to P2P it!

Hello,

I have a Tubes4Hifi PC5 line stage. Would there be a way to add a headphone output or connect headphones to the output? If not and the power supply allows, I have a 12au7 headphone amp that I started to build and thought maybe I could incorporate it into the line stage.

Thanks

Has anybody to sell at least 1 pcs of LT3094? Thank you.
Welcome for any info where can i buy it for a reasonable price.
I can trade for hard get stuff...2sk170BL-GR, Black gate fk220uf, lme49710-12-13 metallcan...

Hello,

I'm interested in floating supply power amps like Transnova Hafler, QSC, Acoustat, Dalix, and I just found these diagrams on my hard drive.

I do not know where I copied these pictures, I search for their provenance.

I searched on google, on this forum but nothing.

I like the use of op amp directly on MOSFET

Thanks
Best regard
Sébastien

Hi Forum members,
I am seeking your help on using Beyma 18p1000fev2 subwoofer for home theater. Is it good idea to tune the box lower, say closer to 22hz? It's for home theater. Spec can be found below

https://usspeaker.com/beyma 18P1000feV2-1.htm

Hi at all.
IF i have an DHT triode amp with 3K : 8ohms output transformer.

And If i have a compression driver working since 2.5kz with 8ohms curve and also a 5 ohms resistor in series.
The plate load change with a 8 ohms driver , and the additionaly 5 ohms series resistor ?

Or this resistor does not change the load that the plate tube see since 2.5kz ?

The series resistor Influences in some way ?

Santiago

Interested in the various ways there are whereby one can generate a negative voltage within a given tube amp design. The more legit, the better. This is asked in the context of avoiding having to install an additional AC line step down tranny. I'm also assuming "flea power", in the single digit mA or so.

I've tried a voltage doubler off an unused 6.3V heater winding. With a slight load to enable an adjustment pot, it barely gets up the -10V needed for a 6BQ5 P-P design. (Next up to bat is a voltage triple-er)

I've seen an RCA design where a capacitor connects to one side of the B+ tranny winding, followed by a resistor to ground. Then to the cathode of a diode, then cap to ground.

Other ideas?

I just got a dead CX-800 pre amp I hoped to repair. it does not turn on.
there are no fuses anywhere that I can see
120 goes into the transformer but nothing come out
input leads for the transformer shows no resistance at all, as in completely open it seems
lifted up transformer to look underneath, it is epoxy encased

outputs are
red black red for 23 gnd 23V
orange orange 14V

I am wondering why I can find no fuses at all (even on the schematic) and the big question, what can I use in place of this transformer

I recently had my crossovers rebuilt. We changed the tweeter resistor from 2.5 ohm to 3.9 ohm to lower the output. It dropped it about 2 dB per REW test. I would like to hear it again at 2.5, but instead of removing the 3.9 (Path audio) resistor, I was going to add a 6.8 in parallel, which would drop the resistance to 2.5.

But that value is on back order from Parts Conn, could I use a different brand, say Mills MRA 12 6.8?

2 questions, is mixing brands a bad idea, and mixing values?

Thanks

Hi everyone, I need some help regarding replacing one of the transistor on my krell s-300i amp.

The transistor has a marking of 1GW (very small transistor). I googled and it shows up as BC847C. I also notice that several other similar transistors have been replaced (bought the amd 2nd hand). I think they don't really last (read about high failure rate of this amp).

I am thinking if there are any alternatives for this? Something that could last longer.

Thanks for the help!!!

I'm not positive on the identification of the PS components.

All PS fets are damaged. Looks like they are IRF1404 but I'm not totally sure. I would think IRF3205 or similar might work here in this amp? Not totally sure. 51ohm gate resistors are measuring OK but need to be replaced.

TL494 IC with several buffers. A few of them are burned and not recognizable:

Q103: ??
Q104: 2A?
D105: 5D
Q105: 1A
Q106: 1A

Is there a schematic available for this one?

https://www.crutchfield.com/S-oml7d...C_Wa2scYmqp86MxlQXGmHy6Y3RjQlgYhoCqucQAvD_BwE

Hi all,

Hoping I can get some help with this old Cyrus One. The left channel sounds weak and has mild distortion. I’ve been through with a scope with a 1khz sine wave and the Voltages and wave form look great and voltage at the power transistors are identical. I’ve checked and cleaned pots and even applied the signal directly to the power amp circuit, bypassing the controls. Also there was a bias issue on this channel, I’ve reduced a resistor in the bias circuit and got 8mv. Also recapped this circuit. Any ideas guys?

cheers

Such capacitors I have never seen before:
https://www.eeworldonline.com/cde-snap-in-aluminum-electrolytic-caps-handle-600-vdc/
https://www.cde.com/new-product/380lx-and-381lx/
https://eu.mouser.com/ProductDetail/KEMET/ALA7DA331EE600?qs=sGAEpiMZZMvwFf0viD3Y3a3yb5D6sPUg3Mw1Ii53gqabpUqe8jhz/A==

The usual method of connecting electrolytic capacitors in series to increase the value for VDC (when the ESR value doubles) should therefore be a thing of the past. In case of replacements of four caps all can operate in parallel mode up to 550VDC supply voltage.
Are there any experiences ?

I have actually 2 amps from the same person with the exact issue. No audio. Amp Powers up and draws proper idle current and has no shorted mosfets, or output transistors. I have had many prime mono channels amps that an inductors has came from the board. But I have seen this a few times and can not fiqure it out. I need a signal generator. For now in going to push an audio signal into the amp and try and follow the 50htz signal? It's not so easy the way the board is layed out. Just wondering if anyone has found a solution to this issue already? Or some advise

Hi all-

These days it seems I find many NOS tubes have gone gassy from age. Tube testers do not check for this. Is there a jig or circuit or DIY rig that does check for gas? Thanks.

Ive got this amp, a bit un-familiar. The driver board is epoxied. The amp attempts to power up for a brief few seconds but then falls straight into protect. All transistors are measuring OK and everything seems well enough in-order on the pcb. Any thoughts as to why it stays in protect?

Photo

I am looking for step-by-step instructions, with photos, to show how to set the CDM-2/10 laser diode voltage to 50mV for correct focusing of the TOC on a CD. I have the Philips C.D.M.-2 service manual, but it is not specific on which resistor on the control board (CB) must be used. I have seen comments here that it is located in the bottom right corner of the CB. I believe this to be R3131.

I remember searching the web and finding a site where this information was contained, but have since lost that history on my browser. I have read Laserology by Lamizator.eu, and while very informative, it is not specific enough for me. Yes, it shows the pots and what they are used for, but not the resistor location on the underside of the CB.

I have also read CDM2 Revision by Bakura, and while informative, not what I am looking for. The closest I have found is the CDM 4/19 to CDM2/10 laser swap blog on audiokarma.org - and while getting close to what I need, it is still short of what I once saw on the web.

Any pointers or URLs are most welcome.
Thanks

I mainly made this document for my own records but I think the design is a good way of getting decent output from cheap high Qts car subwoofer drivers. The measured maximum output is >115dB/1m @ 30Hz.

Hey guys.

Have started a wedding band who are now looking to purchase its own PA.

We want to go with just tops for convenience and logistics ( don't want the hassle of carrying subs to every gig )

Which speakers would you recommend that can cover the whole band? And are 12 or 15's better.

Details:

7 piece band - drums, bass, guitar, keys and 3 vocalists.

Gigs - standard weddings / corporate 100 - 150 people.

Budget IS important so ideally looking for the cheapest speakers that can get the job done.

Thanks in advance

Apparently it is possible to build a Hi-Fi 'chip amp' for a very low cost. I thought it might be an interesting exercise to design one and build it later at an appropriate time.

The unit will be wall mounted on a rack similar to this one:

Initial 3D model of the case is as shown in the attached graphic.

Plan to use an external power brick and an amplifier chip that is capable of 2 Watts to 5 Watts.

Amplifier board like this one?

I see lots of very sophisticated projects here with people doing smart stuff with Arduino and Pi and all sorts. So I feel suitably chastened in posting this but may be of some interest to someone.

Having finished my first Chipamp I was left with a Cambridge Audio A1 case and some of the internals and decided to repurpose them into a preamp to feed the Chipamp. All very simple stuff. I sourced a modest 30VA 15-0-15 toroid. I stripped out the old regulator system (just Zeners) from both the main preamp board and the input board and installed a proper linear regulator based on L78/7915. I did some rerouting on the input board to cut out the the tape loop and give myself just another line level input. Then obviously I had to rewire everything together and in doing so tried to adhere to some better routing than the original design allowed (given that it had a comparatively massive power amp board in there).

So the design (as per original) is simple. An inverting buffer on input, feeding a shunt feedback Baxandall tone circuit (so again inverting), feeding a pot and then straight to output. So this last stage is a 'passive' preamp. I use short cables and the pot is 20k (ln) so no issues there, but I will be adding a final buffer stage just for versatility to allow longer cables if wanted (may enable both buffered and non-buffered outputs).

On to opamps. So much written I know but I will keep it brief. It came with TL072 in both stages. I am a great fan of TL072 from long back and in these low or unity gain circuits I didn't see a compelling reason to change, but I had socketed the boards and so experimented a little. Tried 4558, NE5532 and AD712 (as used in more upmarket Cambridge Audio A3i). I measured all of them for noise (pretty negligible in all cases but measurable differences) and did some listening tests.

OK my ears are not good and I am not therefore a great guide on sound quality - whatever that means. In all honesty I really couldn't reliably tell them apart. Its quite useful that the tone circuit is switchable so its possible to switch one op amp out of circuit and this did reveal a very slight degradation due to the 4558 - very slight, but female vocals just didn't sound as convincing (at least not to me). For the others I couldn't have reliably told whether the tone circuit was on or off with a blind test. So on this criteria alone the 4558 drops out of contention.

On to noise. Interesting. The differences are tiny and all versions are getting close to the noise floor of my ancient Levell muV meter but here it is. The noisiest (in this circuit) was the TL072, the quietest was the AD712. The total measured difference (full volume, tone on) was only around 10muV from best to worst but given the low levels I was measuring (20-30muV) I guess this is quite a large percentage. However .... it was impossible to tell them apart in practice unless my ear was right up against the speaker. In that case I would say the TL072 noise was a bit more objectionable / noticeable as in being more popcorn like.

Then I am going to add a criteria. DC offset. No surprise here the NE5532 was worst by a country mile. So what? Well the NE5532 implementation would be unusable without some switch on delay relay / switch off mute. I say that because if ever by accident you were to switch off that preamp first (or switch it on last) with NE5532 on board there would be very loud, very unpleasant and possibly damaging loudspeaker cone excursions. I tried it without tone enabled and volume turned down and it was bad enough. The TL072 by comparison was relatively benign (but you would still want to avoid a mistake of powering down preamp with power amp on). The AD712 was just a dreamboat. I couldn't measure any DC offset and it starts up and shuts down almost silently.

Perhaps no surprises - a circuit designed with JFET opamps works better with JFET opamps. But then the performance of the AD712 in comparison with TL072 did take me aback. Received wisdom is this is an ancient 80s opamp and offers no real benefit over the TL072. And I hadn't realised the benefit of DC precision is potentially simplifying a design. It was therefore measurable better and much more practical. In fact for the audiophile approach, DC offset is so low i could easily remove at least two DC blocking capacitors per channel if I wanted to. Picture of new internals just for the hell of it.

I have 3 way DIY speakers. Midrange is Accuton 173-6-090, Scan Speak Revelator tweeter, ring radiator. The crossover is 6 dB per octave. The midrange is 120uF and 0.56 mH. The tweeter is 3.9 uF. Distortions, sibilants are heard in the area of high tones. I tried other speakers in the setup, there were no distortions or sibilants. I read about how the SS ring radiator can’t play low. I have experience with the Vifa ring radiator, which also couldn’t play low without distortion. I would like to keep the crossover 6 dB per octave, because I have expensive elements, and I also like the connection and phase correctness of such a crossover. I wonder if you know which tweeter could play with my Accuton midrange and 6 dB per octave crossover? Best from own experience with similar drivers.

I have a Becker BE1480 tape deck in my car and lately it has eaten two cassettes. I'm thinking that I'd need to replace the pinch rollers in this 32 yo deck which would seem to be long overdue.

When I open the deck I see a tiny plastic disc holding the pinch roller in place. My question is: can I pry/pop off the disc in order to replace the pinch roller or should I not tamper with this piece?

I'm sure others have come across this when selecting a power transformer. For a project I'm working on, I found a power transformer with the perfect voltage and current high voltage winding and a perfect filament current rating. Problem is the filament winding does not have a center tap. I've had the same situation before and a solution I have found that cancels background filament hum is to add bypass caps from each side of the AC filament line to chassis ground. I find ceramic caps work best for bypassing and 50V multilayer ceramic caps are small enough to fit anywhere. I ground the caps to the chassis and not directly to audio ground circuits. The 120V AC power inlet third prong ground also connects to the chassis and not directly to audio grounds. Although audio grounds do connect to the chassis, all audio grounds are wired together. Copper wire is a better conductor than a chassis giving some degree of isolation between audio ground and AC ground. I have never had a hum problem (so far 😊).

Below I Haves shared Measurements of My Driver using DATS V3
FS comes out to be 86.3 and if can be clearly see a dip of graph which the software has analyzed as fs because of impedance peak.
but can be clearly seen it can play below 86.3 hz
so my question is how to calculate fs in such case as modeling software modeled graph will be only upto 86 hz

Hi,

I am looking for a remote control for the Perreaux SM6 preamp or for the codes for the programming of a programmable remote control. Anybody knows where I can find the codes?

I thought I'd re-animate this project because it my promote discussion between the factions. Summer's here. It's barbecue time so I want to create a blue-tooth boom-box. It has dual power sources AC mains and a 12v rechargeable DC battery. Somebody has to carry this so I'll limit the size to 20 litres.

At this point anybody in the car stereo business need to seriously re-think their priorities. The 12v battery needs to last all day. throwing more power at a problem can never be the answer. (Within reason) the priority has to be dB per watt. Having torn down more systems than I can recall I have an inkling how the big box manufacturers have addressed this issue.

My draft design incorporates 6 drivers (2 x 3-way speakers) in a shared 20 litre box. The woofers are 6" and the single port is tuned to 90Hz. The efficiency theory starts at the signal: do not ask the amp to waste power amplifying inefficient signals. If the amp is not amplifying signals below 70Hz (12dB per octave) then it has twice as much power to power the rest.

It's just a holiday Boom-box. It doesn't have to be perfect.

Can anyone help with the conversion of the amp below to Si transistors?

Use will be a general purpose test bench amp.

Many thanks in advance.

HV20821

Asia'x capacitors,Yunxing Aluminum Electrolytic Capacitors,Yunrui capacitors agent.TOP Quality,ISO9001 Certified RoHs & REACH Approved,Cooperated with PHILIPS lighting for many years, no customer complaint.
https://www.super-capacitors.com/

Got a good deal on Stax ESL-F81 electrostatic speakers. They are in good working condition.

I am trying to figure out what amps would drive F81 best. I have a Class A 20W custom made ECC88/MOSFET Amp: works great with high sensitivity speakers but fails badly with Stax, McCormack DNA-1 Deluxe: drives Stax fine but is not as fluid as Aleph 3, Pass Aleph 3: works fine but clips at higher SPL and Symphonic Line RG11 that works nicely but does not bring anything special to the table. As you can see these are very demanding speakers.





With impedance all over the place from 2Ω to 500Ω depending on the frequency what would be an ideal amp? Please provide commercial models as well as DIY choices and general ideas.

Hi

I'd like to present a diy-instructions for versatile acoustic folding screen called Acoustic Blockchain.
Originally this blockchain was developed to be used in Finnish Hifi events by a Finnish hifi association Hifiharrastajat ry which usually means hotel rooms with minimal acoustic treatment.
It had to be light weight, no breaking parts, acoustic material is safe i.e. nothing to breath into your lungs, no injuries if it falls over, easy to transport,
easy to relocate in room where most effective, usable as a bass trap and effective against room echo/reflections and above all simple to make.
As a bonus it is 100% recyclable.

The Acoustic Blockchain is versatile and easily portable acoustic folding screen made from upholstered acoustic panels.

It has many possible uses:

• open offices/studios
• home acoustics (children's rooms, home office, hifi listening spaces etc.)
• music rehearsal spaces
• etc.

It can be used as permanent or temporary solution as it can easily be folded away (and even put under the bed) when not
needed releasing usable room space for other activities.

This gives you an option to have acoustic treatment in front of windows, doors etc. during critical listening. Also it is easy to find the most effective place for acoustic treatment as you can easily relocate it during listening/making room acoustic measurements.

Direct link to the guide at issuu.com: Acoustic Blockchain
The attached Acoustic_Blockchain_improvements.pdf contains few ideas on how to possibly improve the original design.

Material used is polyester wool with density of 22kg/m3.

Hi guys.
I'm looking for an equivalent or replacement part for this IC: TL783C or LM783C.
I have an AMEK-TAC series 350 power supply and this part is mounted in the 48V phantom section. I fact, it is the only IC or transistor present in this 48V circuit. Here is the circuit diagram.
Can anyone help me?
Thanks in advance.

Hi,

I can get this subwoofer locally at a very good price (don't recommend any other model as in my country we don't have many available) thus I would like to know how well can the 18sound 18LW1400 perform for subwoofer duty, considering this:

-. I have a very small room, maybe 8 or 9 square meters.
-. Use will be for HT
-. Listening levels will be between 85db and 90db (maybe even less)
-. Have DSP capability
-. The idea is to build 4x subwoofers like this

So, taking advantage of the huge area of this SW, the great sensitivity and power handling and kind of poor XMAX, I though:

-. Use 2 drivers per box, connected in parallel (4ohm)
-. sealed box around 50 liters (for the 2 drivers)
-. 500w amp
-. Apply some Linkwitz Transform + HP around 10hz + (-)12db gain across al the spectrum (I don't need 120db@100hz)

With all that, I do have some good performance according to WinISD. I do hit XMAX at around 200W but I am already above 100db@20hz! Also, I would assume that 8x 18" will pressurize my room at a whole other level.

I understand that according to WinISD I will need a TON of power (above 2kW) but if I consider the huge room gain I might get in my room then I can use a higher fp in the LT and reduce the power needed to get similar performance, or maybe get a bigger sealed box of around 80-90 liters.

So, are these assumptions correct? I uploaded some pictures comparing this simulated driver (in red) vs a dual SBAcoustics 10" SW26DBAC76-3-DV in a small sealed box (in blue)

Cheers

Looking for a stereo input multieffects pedals, know any? Also, most effects pedals (Roland, Boss, Zoom) Multi-effects pedals have aux in, is this also channel R?

Want to plug my tascam mixer stereo sub into effects pedal with auto-pan into SPL Stereo Tube vitalizer then to main, lol!

I am wandering here from the Chip Amp pages having just completed an Lm3886 project. I am now keen to explore the world of Class D. So far my only experience is Fiio A1 desktop speaker amp. Pulled it out of the case and it seems to be based on TFA9815T with an OPA2134 op amp front end (nice touch!). This little critter sounds pretty good but I am keen to build a Class D amp for myself. I dont want to populate the boards so really am looking for advice on what sort of completed boards to source with a view to putting it all together. Maybe with a linear power supply (as I feel comfortable making one of those)?. Thanks

I have a pair of SB26STCN tweeters looking for a mid-bass and crossover. I'm assuming the SB26STCN could stand in for similar SB26 tweeters with a slight mod as necessary. I don't have the tools to design a crossover so would be dependent on an existing crossover, so I have attached the various choices. I'm open to using either the SB15MFC or SB17MFC depending on your opinions on each driver and your opinions on the crossovers in the existing designs that use them.
If necessary I could use a NRX part or one of the other SB26 tweeters, but the MFC version would be a little easier. Smallish room, lower listening levels, classical, opera and jazz, SE 2a3 tube amp which works fine with smaller 2-way bookshelf speakers. Don't need too much power or deep bass.

So hoping for some recommendations here. My all means include any other SB15/SB17 designs I haven't mentioned.

SB15MFC-08 midwoofer SB26ADC-04 tweeter. Sutantoroy
https://www.diyaudio.com/community/...tandmount-speaker-project.339276/#post5826477
https://www.diyaudio.com/community/threads/2-way-sb15mfc-08-sb26stc-04.315253/#post-6838731

SB15MFC -4 & SB21SDC tweeters, Xover 3KHz. "The Lockdown"
https://www.diyaudio.com/community/threads/sb15mfc-2-way-the-lockdown.374155/#post-6709256

Not sure how well SB15NRX designs would work with SB15MFC
https://techtalk.parts-express.com/...st-diy-build-sb15nrx30-8-sb26stcn-4-pic-heavy
http://www.audioexcite.com/?page_id=6373 Kensho 2

SB17MFC35-8 midwoofer SB26STAC tweeter. Bagsby The Tributes
https://meniscusaudio.com/wp-content/uploads/2015/11/Tributes-Write-Up.pdf

SB17MFC35-8 midwoofer SB26ADC-C000-4 tweeter Troels Gravesen 61-MFC
http://www.troelsgravesen.dk/SBAcoustics-61-MFC.htm

SB17MFC35-4 midwoofer SB29RDCN tweeter
https://www.diyaudio.com/community/...me-choose-a-crossover-frequency.266766/page-2

Again not sure how well SB17NRX designs would work with SB17MFC
SB17NRXC35-8 woofer and SB26STC-C000-4 tweeter.
https://www.diyaudio.com/community/threads/2-way-project-improvement.379112/
SB17NRXC35-8 woofer and SB26ADC-C000-4 tweeter. Troels Gravesen
http://www.troelsgravesen.dk/SBAcoustics-61-NRXC.htm
SB17NRXC35-8 and SB25STC-C000-4. Ralph's Chameleon
http://zaphaudio.com/DLR/

buongiorno,

this is my first attempt to use a ccs. it is for the driver section (EC86) of a single ended power amp with the 45.

I am unable to obtain a stable operating point as it vary with the variation of the volume control...

• volume control from zero to the first quarter: operating conditions are those highlighted in RED (8mA 1.8V 12V)
• in the transition from the red to the green zone the amplifier emits a bump in the speakers
• volume control in the central part of regulation: the values suddenly change to those highlighted in GREEN (6.3mA 1.1V and at the anode vary from 40v up to 80v and then down to 40V)
• in the transition from the green to the blue zone the amplifier emits another bump in the speakers
• volume control in the last quarter to full: the values return almost the same (highlighted in BLUE) to those of the first quarter of regulation.

strange thing is that the power amp sounds anyway, even with 12v plate voltage ...
what could be wrong ?

grazie!

Hello Everyone,

We can make a beautiful PCB boards with FR4 black core board,also we can make different soldermask like transparent,purple or the other colors you like...
If are interested in,you can contact us!

Sophia

Apologies for cross posting (I think I may have used the wrong forum when I posted my original message).

------------------------------------------

I’m new to the forum and would like to ask if anyone has an old Playmaster 132 that they’d be willing to sell. The design of the amplifier was originally outlined in Electronics Australia in 1971 (June, pp. 44-51; July, pp. 36-41; August, pp. 38-39 and p. 150). I don’t mind the condition of the amplifier (e.g., working, not working, in bits, parts missing).

The reason for my request is that I was passionate about electronics in my teens when the articles for the Playmaster 132 were first published. I couldn’t buy the parts at the time because I didn’t have the money. I’ve just recently retired from a career unrelated to electronics and I’d like to return to the passion of my youth. I’ve worked on a number of radios and amplifiers in the last year, but I yearn for the opportunity to purchase and work on a Playmaster 132.

If anyone can help me or give me some ideas about how best to proceed, I’d be most grateful. I’ve spent a considerable amount of time over the last six to nine months scouring various websites in Australia without success (e.g., eBay Australia).


Thanks,

Old Phoenix

I’m new to the forum and would like to ask if anyone has an old Playmaster 132 that they’d be willing to sell. The design of the amplifier was originally outlined in Electronics Australia in 1971 (June, pp. 44-51; July, pp. 36-41; August, pp. 38-39 and p. 150). I don’t mind the condition of the amplifier (e.g., working, not working, in bits, parts missing).

The reason for my request is that I was passionate about electronics in my teens when the articles for the Playmaster 132 were first published. I couldn’t buy the parts at the time because I didn’t have the money. I’ve just recently retired from a career unrelated to electronics and I’d like to return to the passion of my youth. I’ve worked on a number of radios and amplifiers in the last year, but I yearn for the opportunity to purchase and work on a Playmaster 132.

If anyone can help me or give me some ideas about how best to proceed, I’d be most grateful. I’ve spent a considerable amount of time over the last six to nine months scouring various websites in Australia without success (e.g., eBay Australia).


Thanks,

Old Phoenix

Loved the result when I built the Fane Sovereign 12-250TC plans posted by Scottmoose here:

https://www.diyaudio.com/forums/full-range/246746-12-range-fane-12-250tc-39.html

A friend sold me his pair of 12-250TCs for cheap and I couldn't resists. Now I have a quad of 12-250TC drivers.

Does anyone have any ideas how to create a twin driver box for two Fane 12-250TCs? Or an OB plan with two drivers per side?

Yeah, Ferrari dealers can be that stuck up.

Login to view embedded media

Hello all.
I am posting after a long time . First i am a complete noob on this amplifier thing.
2nd sorry if i did/about to do any mistake out of my lack of knowledge. I intend to buy this particular tda 7293 board because it is cheap and convenient.
100W Digital Power Amplifier Board TDA7293 / 7294 High Power Dual 12-32V Single Channel Audio Amplifier Module for DIY Speaker

3.62US $ 18% OFF|100W Digital Power Amplifier Board TDA7293 / 7294 High Power Dual 12 32V Single Channel Audio Amplifier Module for DIY Speaker|Operational Amplifier Chips| - AliExpress​

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My subwoofer is a 75w RMS old Philips one.
Can i drive it optimally with it?
I intend to run this amp with a 35-0-35 VAC EI transformer (yep i am mr. Cheap 😛 ). One of the top most priorities is to keep it economical .

Other options:
1. Tda8954th btl mode
2. STK 4048

PLZ help

Hi,
I'm looking for a 5.6mH inductor to buy. 5.5 mH will do. Need two.

Thanks!

I got a Philmore sa-2000 and I was wondering if anybody has any information on it or if you have the schematics. There is almost no information on it on the web.

I opened it up and it has 2 x 12ax7 and 4 x 6BM8 in a push-pull setup. All tubes turn on but there is a loud buzz that comes out from the speakers, even at minimum volume. The buz increases slightly at max volume but very little. The heaters are AC. When feeding music through it it is heavily distorded in the low end.

I’m wondering if it’s worth trying to fix or restore it. Does anybody know anything about the quality of this amp? Any schematic out there? I can’t imagine having some unique or proprietary circuit.

Thanks

Hey peeps,

i have a rokit 8 g2 monitor where something with the amp is broken. I want to replace all the inner parts with a class d and a dsp, as I simply want to start playing around with speakers, amps and dsps. So not interested in fixing the original pcb.

The monitor has 2 drivers:

• 1x Tweeter TWTK00012 with 4ohm and supposedly handles 20W
• 1x Woofer WOFK80156 with 4ohm and supposedly handles 70W

(Source: http://www.dancetech.com/item.cfm?threadid=4483&lang=0)


My idea on how to make them work again is to have following audio chain:



Now is the big question what kind of class d to get, i like the idea of getting china class d and play around with them.

For the 20w i found this class d from adafruit: https://www.berrybase.de/adafruit-stereo-20w-class-d-audio-verst-228-rker-max9744
But it looks crazily tiny and not sure if it really can handle 20w.

For the 70w woofer I found TPA3116D2 based 100W class d modules. It has a variable resistor on it with which i could probably turn down the volume
until i reach ~70W.

What do you think? Should that work? Any ideas? Problems i'm overseeing?


Thanks,
obsoleszenz

I have always liked the 14a was thinking using as a top for a 15”

Can anyone give me reasons for or against using this design? Has anyone built the 14a?

I don’t have a pair of WE555s and don’t want clone$. Can anyone suggest a CD driver that can be crossed over at 250-300Hz? Also under 250$ would be helpful.

I have heard tell that the angled connector to the we555 on the original design is critical, can anyone comment on this?

I have rough external dimensions and interior shape but not exact dimensions. Does anyone know where I can find these? A 1930 patent shows some things.

Thanks for the help!

I'm making a housing for a composite horn. The 10" driver will be in a small (barely bigger than the driver) enclosure, and I'm building a larger box to protect the horn and allow stacking and a pile mount (it's for events not home audio).


It will deal with a lot of SPL, but I was hoping/guessing that since none of the enclosure will serve as a resonant chamber, and I'm not going below 200hz With it, I don't need to buy specialized wood (void free Baltic birch vs Home Depot sanded ply).
that's my thought, but we all know what they say about assuming thing!

oh, and speaking of NOT resonating, any recommendations on what to use to dampen the box around the horn? Ideally something light.

What's up guys, I'm seeking some information on the output mosfets for this amp particularly the insertion arrangement.
It was started by another person but they pulled the outputs and I think they got it mixed up, so far I see the amps uses 640s and 9640s (the "s" is for plurality).
It's 5 pieces per rail on one side (10 pieces for complete rail plus/minus), what fets do I insert on the positive rail and what fets for the minus rail?

Focal in their top range likes to tilt their mids and woofers.
Is there any pro to do this?
Maybe time alignment or lobbing?