I’m unsure if the purpose of this forum is a little above my head. I consider what I do diy in the way that I don’t go to Best Buy and choose a big box store brand. I’m getting into using pre made components like amplifier boards, raw drivers and the like to create my audio equipment. I just wanted to preface the question with an attempt to show respect to the legit circuit builders.

I’m about to order this power supply

https://www.trcelectronics.com/View/Mean-Well/EPP-500-24.shtml

and be done fiddling with lower power amazon units. I’m currently using a 24v 6a open frame supply,

Zerone AC 100-240V to DC 24V 6-9A Switching Electricity Supply Module 150W High Power Industrial DC Electricity Supply Bare Board https://a.co/d/drK2azZ

which may be introducing noise into my Dayton Audio Kabd boards, or, maybe the boards may have an inherent low level noise. Either way I like the versatility of the kabd boards and have decided to move into a power supply that will be plenty for my needs with room to grow.

Is there any dissuasive feedback on the mean well 500w 20a unit? Maybe a lower cost route that is as good or better? The amp boards will be In close proximity to the power supply in this small 7”x6”x3” steel electronics enclosure. Is this arrangement too close because of noise issues? I’d be willing to switch to a similar enclosure that would allow maybe ~6” spacing between supply and boards if necessary. Thanks in advance, happy new year also.

With this post I wanted to create a quick reference to all chipamps from TI that are labeled Overture series.
I am assuming all of these should be able to achieve as low of THD figures as LM3886 (0.0033% @1kHz into 4ohm). THD+N probably will be worse since power output is lower.

Since LM3886 is out of stock I figured it would be interesting to use alternatives (even though they are not as powerful).

Overture chip amps list:

#1 LM3886

• 68W into 4ohm, Vcc=Vee=28V
• 50W into 8ohm, Vcc=Vee=35V

#2 LM4780 dual channel

• 55W into 4ohm, Vcc=Vee=25V
• 60W into 8ohm, Vcc=Vee=35V

[equivalent schematics is missing from the datasheet]

#3 LM2876

• 40W into 8ohm, Vcc=Vee=30V
• NA into 4ohm

#4 LM4766 dual channel

• 40W into 8ohm, Vcc=Vee=30V
• NA into 4ohm

#5 LM1876 dual channel

• 22W into 4ohm, Vcc=Vee=20V
• 20W into 8ohm, Vcc=Vee=22V

Any other chips I missed?

Pair of wooden monoblock amp bases veneered in zebrawood. Craftsmanship of construction and veneer are both excellent. There are a couple minor cosmetic blemishes in the veneer (one appears to be some excess veneer glue, which I'd never noticed before), but they are in otherwise excellent shape.

Outer dimensions are 9 1/4" W x 11 1/4" L x 3 1/8" H. Dimensions of inset for top plate is 8" x 10", and 2mm deep. I believe that these were originally intended to be bases for Bottlehead Paramour amps, but I can't say for certain as I am not the original builder and have never owned a Bottlehead amp.

Asking $100 + actual shipping.

Hi!

Can anyone offer if the situation described below is safe for use, the repair needed, or steps to provide the information required to make that determination?

I received a Denon AVR-S700W with a faulty HDMI output from a lighting strike.
I have been using the amp function without any obvious issue.
I apparently overheated it with a new speaker (2.5" & 12" drivers) and it went into protection mode, clicking and showing red/green on the power LED.

After it cooled down, it still clicked, but the red light wasn't coming until I pressed the button.
So I opened it up to look for any obvious burnt components/leaking capacitors and identify the clicking presumably relay at the lower end of the power in board closest to the rear of the unit.
I haven't found schematics or the service manual yet, but will keep looking.


I planned on using a wood stick to lightly touch the suspected relay (outlined in red) to verify.
Touching it caused it to stop clicking and the AVR booted up normally.

I have been using it as a spare amp for my introduction to speaker experiments, so once I figured out how to get to pure direct and out of set-up mode I have not been too bothered by the lack of HMDI.

Anyone tried this amp board?
TDA8954TH Class D High Power Dual-Channel Digital Audio Amplifier Board 420 I1A2 192948093630 | eBay
I think to purchase one and to try to convert it to 4 SE channels to make active speakers with a DSP.
And maybe one cheaper mono board with the same TDA8954 IC for subwoofer.
How it sounds for full range speakers?
The default sampling frequency is 350kHz, but it can be set up to 500kHz, according the datasheet.

Hello to all forum members. I'm Jürgen, I come from a village in the Teutoburg Forest in Germany and have been fascinated by good hi-fi systems for about 40 years. I once trained as a radio and television electrician, then retrained on IT systems, but had to retire early. In all the years I have repaired and restored mountains of hi-fi devices and have always done the same work that I have now "forgotten almost everything" that you might need to build a fine device yourself. So I'll hang around here a bit as a professional dilettante in the forum and hope that I can refresh my almost 60-year-old brain again.
Well then, have a nice evening everyone and bye until then...

I'm looking for two pairs of used MN2488 and MP1620 Darlington transistors. From what I've read all the ones on eBay are counterfeits. If you have the 3-leg dual resistor blocks that were used with them I could use them too. These parts were in many Sony receivers. Thanks!

From this amp under
https://www.hifiengine.com/manual_library/quad/240.shtml
I haven't heard before.
A friend of me found an offer of this model for 500 €
Maybe one of the members know, how this model sounds - thank you very much.

P.S.: Schematic is to find in the user manual.

best offer
Might be new or used
I don't know
UNTESTED

VACUUM TUBES -- (2) 6C6 (2) 6A6, (4) 25Z5, 84/6Z4, (2) 1626 National Union US Navy RCA -- NH USA

Integrated amplifier is dual mono with left and right pre-outs. When connecting an RCA (L & R) from integrated pre-out to subwoofers Left and right inputs, both speaker makes a sound even if the balance is all the way to the right, reverse is true if the balance is all the way to the left. Removing the RCA cable from pre-out to sub removes the problem. Would it help if I only connected the "+" from left and right and connect only a single "-"?

Hi!

I have a pair of Precision Devices 2450, 24" speakers, which I´d like to build something else for than regular ported boxes. I have read quite a lot and experimented in hornresponse, but feel that I don't have enough experience too decide if i'm on the right track. I don't want to bulid something that doesn´t work.
On PD:s site they say that they should work in horns, but apparantly the BL isn't sufficient for example paraflex.
I´m curious about ROAR, Tapped Horn or 8th order bandpass solutions, but need some help to decide what would work. For ROAR and TH I have had some success getting a reasonable response curve, but 8th order bandpass is just a mess. I know there are a lot a very skilled builders here who propably could make it so much better.

Some things like phase response and group delay I don't have a clue how it works and would appreciate some info about that too.
If someone is interrested in helping me design boxes, I would like them to be no bigger than 185x80x90 Height, Widht, Depth, so I can get them through doors.
I'm attaching some pictures from boxplan and hornrespons so you can give me feedback.

The other part of the system will consist of 8 pcs 10", 4 pcs of 6,5 and a pair of horn tweeters. The PD 2450:s will have a Yamaha P7000s each, the 10":s a QSC PLX3402 and the 6,5 and tweeters a Pioneer SX1250. The equalisation and filtration is done by a Driverack PA2, except for the crossover between the 6,5:s and the tweeters.

I would appreciate any help I could get.

Hi. I am looking for sources of low capacitance pure copper cable suitable for making a headphone extension cable.

It would help if the cable were reasonably priced.

Any suggestions?

Just finished recapping my SA/1's with four CDE DCMC104M100DF2B 100,000uF, 100V from Digikey per chassis to replace the 39 year old Mallory's 29,000uF 80V.
They still have an inventory of those so all Threshold SA/1 - SA/2 - SA/3, S/200, S/300, S/500 and S/1000 owners can order fresh ones.
These were even lower in height than the old ones but fitted perfectly in the 3" clamps and the groundplate drilled holes.
Would the 100,000uF per can be a problem?

Although they were manufactured/shipped from the CDE factory this year to Digikey I still softstarted them within three hours from zero to 220 volts with a variac. I start the Thresholds always with a variac (but than in a few seconds ;-)) for minimal stress especially for the on/off Airpax circuitbreaker.



The FET Eleven/g (a FET TEN 'e' series for the German market) has two Sprague Series 53D 35V 15,000uf axials and replacement for those is hard.
The best I could find were Vishay/Sprague 25V 18,000uF axials. Over the old ones I measured 23 Volts DC with 230 Volts AC.
Would that be a problem?

The schematics are way too complicated for me to fully understand. Could you guys tell me what "VCCD2" in the schematic is , and where does it come from (origin)..?

Copyrighted material removed.

Could we dispense with bulky isolation materials, and rely on plasma instead?
https://www.nature.com/articles/s41467-023-38522-5

Used but top condition. One pair 3,30 Ohm and one pair 33,0 ohm. For all 4 pieces 40 euro plus 5 euro shipping inside EU.

Just for fun exercise here decided to run the schematics in the simulator.

Original Cordell's schematics is attached:


Here is the TI application note schematics for the servo:


And here is my take on it - drafted in TINA TI simulator:


It is almost the exact copy of the one from the TI application note. Super gain clone has its phase reversed back and so the LM3886 outputs the signal with the same phase it was fed to the input of the first opamp. I did not bother with that additional step in my schematics. It allowed to save on one additional opamp. I am using OPA2134 as I personally listened to it and I like the sound a lot. It also has ah-ok DC precision to work as a servo. Loading OPA2134 with easier load (2K in my case) should produce less distortion - according to the graph in the datasheet.

Servo values got adjusted to give difference of 47dB at 20Hz - that is between usable signal and the feedback one:


Frequency response is -0.03 dB at 20Hz and -0.11 dB at 20KHz. That is with the gain of 20dB:


Stability components were added to the schematics to insure proper performance of the LM3886. As far as I understand opamp stability theory - idea is to make sure we are avoiding oscillation condition where the output signal phase is inverted 180 degrees and fed back to the inverting input of the LM3886. With given values for stability components phase is preserved under 180 degrees shift up to 934 KHz and depicted in the graph below:


Comparing that result to the open loop gain graph for LM3886:



At the end I just wanted to mention that I am not an expert in the field and could have made mistakes - therefore I would really appreciate any input on any part of this analysis.

Attached is the zip file with simulation.

My audio system has always been multichannel surround built around a digital home theater processor. What I'd like to do is isolate two channel sources from multichannel sources and run two channel stereo CD player/DAC and turntable/Pearl 2 phono pre through the Iron Pre I'll be building and leave all the multichannel audio (TV, bluray, roku, etc) to the current surround processor while utilizing the same amps and speakers at all times.

A line level switcher would allow this, but currently my passive sub is driven by the processor as I'm utilizing all the xover and eq controls there so that complicates things. I could ignore the sub controls on the processor entirely and instead run the sub via MiniDSP for instance but I'd like to avoid that.

Surely I'm not the first nut to do this without wanting to unplug/plug RCA cables each time. What solutions have others created?

For reference current front end is B&K Reference 50 S2 driving dual mono PassDIY F6 for left and right speakers, a monoblock F6 for center channel speaker, a Crown XLS1002 for passive sub and a B&K AV2500 for surrounds. Main speakers are DIY Bordeaux, center is DIY Statements center, sub is DIY Dayton Ultimax 15.

I've been trying to find a definitive answer to the question but I can't seem to find anything directly relating to my intended use. The intended us is... .

• I have a stereo, dual-mono constructed, 2-stage push-pull 2A3 power amp that requires a separate power transformer for its driver stage.
• Each channel of push-pull 2A3s uses its own 500VCT 150mA power transformer. Those are on the chassis, ready for action.
• Each channel will use a 6N6P LTP with its plates DC-coupled to the 2A3 grids. Each 6N6P triode will be drawing about 15mA, so I'll need 60mA for four triode.
• I need a +150VDC plate supply for the 6N6P tubes which will be 'stacked' on top of the +325VDC plate supply for the 2A3s.
• I already have the 6.3VCT 1.2A transformers necessary for the 6N6P heaters.

I don't have a lot of room on the chassis. It's an old project that I didn't lay out very well. Oh well, it is what it is.

I was thinking of using a pair of Triad Magnetics isolation transformers (117VAC:117VAC) and rectifying the 117V secondary with CRC filtering to bring the rectified voltage to +150VDC.

My choices are:

• Triad VPS230-110 which is a split-bobbin design.
• Triad N-48X which is a single-bobbin EI core (I think).

The VPS230-110 is a bit smaller, so I'd like to use that if possible. But it uses split bobbin construction. I understand that has the lowest capacitive coupling of the various transformer configurations, but does that come at the cost of a lot of uncontrolled electromagnetic radiation? I don't want to inject hummmmm into everything.

The N-48X is an unknown quantity, but I know Eli Duttman has used that series of transformers in some of his amp designs. Do single-bobbin EI core transformers control their electromagnetic radiation better than split bobbin transformers?

I understand toroid transformers have the tightest control over their radiation, but they also couple line noise to the secondary more readily, and they also have a bigger current surge at power on. I could go with a toroid if it's absolutely necessary, but they're all pretty large. The minimum diameter in a transformer with 120V secondary from Antek is 3,6" for a donut rated at 50VA (120V at 400mA). That's way more than I need.

What's better in this particular usage situation? Split bobbin? Or EI core? Or does it not matter?

Just completed building an ACA v1.18 to go with my 2 plus year old ACA v1.16.

1. The ACA v1.18 does not make that sound heard through the speakers when you first turn it on, unlike the v1.16 which does.

2. The ACA v1.18 runs cooler than the v1.16 as a stand alone stereo amp.

3. But it runs much hotter then the v1.16 when used together in the Mono RCA Bridged configuration.

Can someone please tell me if these differences between the two amplifiers are typical, or not? If not, any suggestions on how to address?

Also, one of the v1.18 LEDs is slightly dimmer than the other.
Is this something I need to be concerned about?

Thank you for your consideration and any help you can offer.
Yours,
Michael

Hello,

i am new to speaker design. I am inspiried by the Apple HomePod, where the woofer is facing down and the Homepod have 5 tweeters.
So my questions are

1. is it possible to direct the woofer to the bottom? Does it affect the sound?
   1. Or it is only possible when the woofer plays only up to 800 Hz and the tweeter plays from this point. 800 Hz due to sound localisation. First research says that frequencys below 800 Hz cant be located by human ear. Is it right?
2. is it possible to have more than one tweeter in one speaker?
   1. How do the tweeters affect on themself? (Interference?)

My tube preamp (Audio Hungary Qualiton apr204) either wears fast the line stage tubes (6922) or all the 3 pairs i bought were defective (1 pair genalex gold lion, 1 pair electroharmonix and one NOS pair voskhod 6n23p) They lasted about 6 months with aprox. 2 hour per day listening. One day when i turn on the preamp, the 6922EH catastrophically failed with sparks and flashes inside the right channel tube and VERY LOUD noises heard from the speakers. The previous day before total failure i was hearing clicks, pops and squealing from the right channel. Fortunately my Power Amp and speakers survived.
I disassemble the unit and copy the line stage schematic from the pcb traces.

The schematic is this:


I have no experience with tube designs and i would like to know if my preamp drives those 6922 hard and reduces their lifespan.
Any suggestions for modding the schematic or was just bad luck with defective tubes?
Also i want to change the gain of the preamp...did someone know which resistor value to change?

Thanks in advance!

I have been trying to figure how the plosive keys work on the Voder. I have already figured out some of the stuff with the key.

I have a diagram from a Patent , that shows how the plosive key works but I don't exactly know for sure if its 100% correct. I am also guessing things could have been changed between the actual key circuitry and the circuit diagram in the patent, but though it also seems that patent for the Key was applied for and granted after the Voder came out?

What I need help with :

- I need assistance on figuring out the filters for the pop in the beginning before the actual plosive sound? I tried using audacity to figure it out haven't been successful yet. In the plosive circuit diagram it seems the pops are generated by a 2 separate filters connected to the unvoiced/ voiced sound sources based on if the plosive is unvoiced or voiced. Also it seems like each filter are really 2 RLC bandpass filters combined in parallel? Obviously those might be not the real circuits used to generate the pop just representative of the circuits used.

- Theres a 3rd RLC bandpass filter on that plosive key diagram that seems connected to the output of the 10 keys and filters on the voder, which is labeled resonance controls , that I haven't figured out yet. and the patent doesn't really explain what it does. The explanation of what the plosive key is doing doesn't explain what it is doing either. I am guessing it could be representative of something. I am guessing the resonance controls could be the 10 keys and that filter is maybe representative of 1 of the 10 bandpass filters ? But though I have always thought the resonance controls meant both the keys and the filters in that circuit.

- How the plosive key can switch between the K and G plosive just by how fast you press it down?

- Figuring out how to duplicate the key using modern switches and modern electronics. I was thinking of maybe using one shot timers to set the timing of each step ?

I have an explanation of how the key works, basically the key has multiple contacts and when you press down on it, it goes through the contacts as you press down the key.

How to make K sound using the K/G plosive ley to say the word "Key" :

Hold down wrist bar , press the K/G plosive key , and the 6th key on the voder at the same time.

steps of the plosive key when the above is done :

1 ) removal of voiced energy from resonance controls and all filters

2 ) discharge capacitor in resonance circuit to make the pop sound shown at A

3) interval of silence

4 ) connect filter 6 to unvoiced source to produce noise shown at B

5) When key reaches bottom reconnect voiced source , so you can press the keys to make the "e" sound shown at C

If the K/G plosive key is pressed in 1/2 or 1/3 the time (faster?) , the key will produce the G plosive instead of the K plosive.



Timing for the K sound :



information about the G plosive:
- It seems like the timing is backwards from the K plosive. as you seen above the timing is a 6 millisecond pop , 40 millisecond of silence , and 31 millisecond of white noise through the 6th filter, for the K plosive. Using audacity and finding where it says a G I found out , the timing is 31 milliseconds in the beginning, the silence, 6 milliseconds at the end. I am not sure though if the pop and the actual plosive sound is backwards , whenever the G is produced.

Plosive key circuit diagram :


actual photo of plosive keys :
if you look closely at the actual plosive key, it has the same amount of contacts on the key as the above circuit diagram , which is how it was figured out this circuit diagram in the patent is some version of this plosive key.

Pair MTX 15RD1 8 ohm. Like new condition. $100 + ship. ff, zelle
GONE

In case of repair of vintage amp devices there is often a problem to find the associated replacement parts with right quality standard. This is particularly the case with many Japanese power devices - both BjT's and lateral MOSFET's.
One example is the Hitachi lateral MOSFET series mentioned above.

However, looking for devices as spare parts carriers only makes sense if they are not particularly popular - i. e. no collector's prices are being asked for them like on this model:
https://www.good-old-hifi.de/hitachi-hma-7500/
or
https://www.diyaudio.com/community/...r-amp-schematic-and-pcb-images-wanted.387093/

Therefore few populare amps like Harrison's K series are much more better for this aim, because in most cases such amps are faulty, because nobody is able to repair the potted hybram modules on ceramic PCB - check out
https://www.diyaudio.com/community/threads/harrison-type-k4000-k-4000-mkii-2x1000w-4ohm.147392/
and
https://en.audiofanzine.com/power-amplifier/harrison-information-technology-ltd/
I. e. such amps for Hitachi MOSFET's as spare parts are always cheap and one have a lot of genuine Hitachi's MOSFET power devices as NOS spare parts and no copies resp. counterfeits.

I assume, there are a lot of other not popular and thus not expensive PA mixer/keyboard/active loudspeaker power amp models equipped with such power MOSFET's.
Thank you for listing of such models.

Another option is to look for diy projects in used condition like Elektor's Crescendo or Mini-Crescendo
Unfortunately something like this is offered even more rarely despite the numerous diy projects that were described in the 80s and 90s in a lot of magazines.

Some URL's
https://www.diyaudio.com/community/...fier-for-diy-described-by-paul-kemble.220923/
https://www.diyaudio.com/community/threads/hitachi-mosfet-power-amplifier.127297/
https://www.diyaudio.com/community/threads/chinese-hitachi-mosfets.235479/
https://www.diyaudio.com/community/...t-driving-question-hitachi-amplifiers.192257/
https://www.diyaudio.com/community/threads/testing-hitachi-mosfets.41966/
https://www.diyaudio.com/community/...itachi-app-note-lateral-fet-amplifier.391700/


P.S.: The successor models from Exicon (fifth attachment) are probably less common than the Hitachi MOSFET's mentioned, making them even harder to find.

Have a Marantz PMD-321 in need of the Tray Switch.
It's the same Switch as used in all Philips CDM-12......./ VAM12..... etc etc
The Part Number from the Marantz Service Manual is;
4822 276 13222
It looks like there was an alternative Part Number for different Countries (?) This was;
SM000300R
It also lists the (possible) Manufacturer and their Part Number for this Switch. This being;
SINMEI, QAS12299

Does anyone know of any sources for this Switch?

Thanks,

P.

I would like to re-install the original tonearm-lift, which was replaced by thorens's front-"switch".
I have the lever and was able to insert it, but it seems something is missing:
The lever can be rotated 360° (there's no upper/bottom stop), and the tone-arm literally falls down, there's no "break".

Hello,

I've had problem with non-working phono amplifier. Capacitor C409 and C410 were swollen and there was cold joint near transistor Q401 - I replaced Q401 and Q402 with place.
Phono is working now, but there is problem with MC hum very similar to Brown noise on left channel (upper track on schema where Q401 is). On MM there is very little noise, but where volume knob is near 80-90%, so it's acceptable.

What I have done to this moment?
I replaced resistors R431 and R432
Solder again all joints for this channel from schematic
Replacing with the places all transistors Q401,Q402,Q403,Q404 left to right etc.
RCA terminal is ok.
Recap all others electrolytic capacitors.

Could it be problem with opamp NJM2068DD? Other resistors may generate noise? I have no idea and any others clue what it might be.

I'm using a 65W amplifier with the speakers that recommend minimum 80W power. However, I don't find any problems with this combo. Moreover, I'm happy with them.

Nevertheless, as there were series 2 of amplifiers available and they had 100Wpc power. Although there's nothing wrong with my current system, I'm curious that if I change the amp to the series 2, will I gain a huge difference?

Amplifiers
Series 1: Braun Atelier A1 (65W @ 4 Ohms)
Series 2: Braun Atelier A2 (100W @ 4 Ohms)

Speakers: Braun LS200 (4 Ohms)

Solved!
Working on this unit, and need the schematics.
Got a service manual in pdf (38 pages) that seems to have been at least 41 pages in total.
The copy i got has no schematics....
Note: This is not the AU- or the QX- unit!
Thanks in advance 🙂

Hi all, I have been gifted an old amplifier I know nothing about. All it has identifying it is, Wak power 700a. That's it.
Please help

Having purchased Magnepan LRS's, which I'm completely blown away by, I thought I'd try adding two subwoofers. Although the smallest Maggies, they were quite confronting (I've got used to them now and don't even notice!) so my preference for open baffle subs to best integrate meant putting up with equally imposing stacked H frames till I discovered Mr Linkwitz.

https://www.linkwitzlab.com/woofer.htm
I built a pair of Dipole Woofer 3's slightly modified (not in dimensions) for ease of construction and practical shape/finish/use. Cutting sheet for 18mm MDF 2400x1200 and construction photos available by email.
They are yet to have top veneer and grill cloth frames but photo shows neat size (KEFs in background are retired). They use a pair of 12" OB woofers (BIANCO-120B150) per channel. Very inexpensive approximately $500US all up including materials.

line.com.au/sb-audience-bianco-12-open-baffle-woofer-150w/sb-audience-range/sb-acoustics/speaker-drivers/audio-speakers-pa/bianco-120b150-89896/1002166/pd/

I used this inexpensive low pass filter leaving the LRS's full range on their own monoblocks.

ps://www.wagneronline.com.au/subwoofer-low-pass-filter-active/crossovers-assembled/speaker-components/audio-speakers-pa/ax100-6812/962104/pd

I've not got any measuring equipment but they integrate very unobtrusively and smoothly into the LRS's. I've used a test CD running c/s 100 down to 20 and there is a smooth transition from LRS's to subs. Musically they match, only reinforce and do not dominate. I'm a retired classical musician so I have good ears!

Hi all,

(Apologies if this could be placed in a better subforum, mods, feel free to move).

I'm a hobbyist tinkerer and cassette / vinyl lover. I moved from the states to Europe in the last year and have been enjoying getting myself set up with a new (to me!) Hi Fi system. I recently acquired a Philips 982 home stereo center, which is a combo turntable, cassette deck, and tuner. I got it for free as it was totally inoperable, and I've since gotten most features working. However, I'm a bit stumped with an issue I've run into and was hoping someone out there with more experience than me could shine some light.

As of now, I am only getting signal out of the left channel heading to the speaker. On this machine there are only 2 outputs for speakers, L & R. They are 5 pin DIN 180* connectors. I've done enough troubleshooting to figure out that the issue lies somewhere before the speaker output. The two fuses are functioning, and the terminals themselves are fine. After probing around the PCB with my multimeter and speaker wires, I have been able to get a buzzing sound coming from the R Channel, but no music. I have inspected and not seen any obviously blown or broken connections, and testing for continuity shows a clear line from the speaker terminals up to the amplifier (i think!).

I'm wondering now what my next step to check would be. I'm pretty handy with this stuff but am not a pro or an electrical engineer. The only copy of the service manual for this machine that I could find online is pretty hard to read for me (image quality as well as component numbers etc), but I've attached it here, as well as a picture of the machine.

If anyone has any thoughts or what you would inspect next, I'd really appreciate it! Can of course post up pictures of the boards and guts if necessary.

Many thanks!

Nick

Manual: http://freeservicemanuals.info/nl/servicemanuals/viewmanual/Philips/22AH982/

HI,

In my new DIY project I decided to use Intel platform instead of RaspBerry PI4 using Daphile or Volumio.

https://www.diyaudio.com/community/threads/my-digit-berry.399053/#post-7344546

I could start from a mini PC, removing the case, or directly from a dedicated mini mainboard. Unfortunately, it seems that all new mini pc's or motherboards don't have a digital audio out connector (toslink or electrical coax). Now, I'm wondering what's the best way to complete the audio chain... specifically whether to use a DAC (USB in - toslink out), USB sound card, or use an hdmi audio split.



In your opinion that is today a good and cheap list of chain components considering that:

1) Your system must have a toslink/coaxial digital output port

2) HDMI out port

3) ethernet port port

3) USB 3.0 ports



Thank you

I'm using a set of Braun Atelier system consisting of an Atelier A1 integrated amplifier and a pair of LS200 speakers.

Today, I got a new bigger power amp. It's a/d/s/ PA4. Launched in around late 80s, it's one of the Atelier series.

Since it's a separated component, a power amplifier, it needs a preamplifier. The preamp which was launched with it is an Atelier CC4. The question is do I need to find the CC4 to use with it? However, I observe the A1 of mine has a pre-out channels. I wonder if I use the pre-out function of the A1, will it give the same sound quality to the CC4 preamp?

Although I have very little on Electronics, I've searched for the schematics of both A1 and CC4 and compare the preamp section. Yes, they are different. Yet, they're the same Atelier series. So, do they close in performance?

We are starting production of the new HyperDrive-2 headphone amp / preamp. This utilizes a 6N1P tube buffer and solid state Class AB headphone amp output stage for up to 2W into 32ohms. It has 3 selectable inputs and two outputs. All operation is controlled with a microcontroller for graceful startup and shutdown. Here it is next to the Warp-1 Class D amp:

Paired with a set of Vanguard bookshelf speakers that have the DNA of the classic BBC monitor:

I bought a 24v/21a Mean Well smps from TRC Electronics a few months ago for my diy audio system. TRC seems like a major online distributor/seller of various smps units. ~500w was the highest power I could reliably find anywhere online, amateur searching likely the culprit.

At the time, 500w seemed dandy, I had 50x2 rms and 110x2 rms amplifier boards for an active bookshelf build. A little over 300w rms plus the inefficiencies with a hundred watts leftover to expand one day.

Big surprise, I’m considering expanding lol. Imagine now, I want to swap my svc 4 ohm bookshelf woofers with a set of monster 5-1/2 4ohm dvc subwoofers. So now I’m looking at two 110x2 rms amplifier boards and one 50x2 rms, 24v/21a can’t do it. Add the center and surround channels in a 5.0 and I’m needing just over 700w of power supply.

I realize that the maximum power demand only applies at absolute maximum volume output but when I’m home before Alison, I sometimes have the urge to shake the house. I’m trying to do without any external subwoofer as a personal design challenge and for aesthetics. Having the bookshelves be the low frequency source also allows me to have two subwoofer locations for room modes.

I see 2kw amplifier boards out there but never a 3kw power supply. How do we produce power over the pedestrian 500w supply units that seem to be the consumer limit?

The 5-1/2 (monster) subwoofers are the Dayton Epique in a small bookshelf with the Tang Band 3” bamboo fullrange. I’m dsp’ing the snot out of the woofers to shelve off the midbass to allow the lower bass to shine. Essentially I’m making the bookshelfs sensitivity in the high 70’s because of the cuts. Winsld shows two Epique 5” woofers will produce sufficient low frequency spl for my liking in a townhouse, but they need power to get there.

Hi at DIY Forum

Im new here.

And not exactly sure if the reason of my question have been discussed here before.

But anyway :

Is it possible to buy ALL the parts, needed to build the First Watt F4 and / or the F8 amp. Including PSU's and pre-drilled chassis and heatsinks ?

Best regards from Denmark 👍🤗

Alf Agerup

I'm restoring a Yamaha CR-3020 and the previous owner has near destroyed the power supply board. I've reached the point where I can't spend any more hours trying to get it to work. Would a solderable protoboard like this work?
https://www.amazon.com/Double-Sided...s_306847011_sccl_29/131-8598011-7649450?psc=1

Also looking for: 1) someone who replicates single sided boards, or 2) someone that can recommend a person or company to replicate the board. TIA!

I wonder if PMBFJ310 https://www.mouser.se/datasheet/2/302/PMBFJ308_309_310-1316760.pdf has the same footprint as BF862?
https://www.mouser.se/datasheet/2/302/BF862-3138317.pdf
It seems as it is but what does Drain and source are interchangeable mean?
I am going to use it as the second device in a CCS.

Hi All,
My first attempt at building a valve pre-amp using a chinese kit was a tough challenge but a worked out rather well. I'd like to say a big thanks to everyone on diyaudio who shared their knowledge. You all really, really helped!!!
Here is the amp working:


For a £100 it sounds it has a great sound and gives a richness, which I didn't get using passive pre-amp. It was tough to build, as it came with no guide and a Chinese circuit diagram, but I got there in the end. It's a bit of a fiddle to use, due to high voltage output when it's first turned on. I did get some advice to reduce that, but I've plumped with adding a manual switch to isolate the output until the device has warned up.

If you are interested in the kit, it can be found here: 12AX7 12AU7 Stereo Vacuum Tube Preamplifier DIY Kit Shigeru Wada Japan Circuit 325646489355 | eBay
or in EU, here: New version DIY kit 12AX7+12AU7+6Z4 vacuum tube preamplifier kit tube AMP | eBay

Here is my guide on building it. So far no electric shocks or amps blowing but with that said, if you undertake building the kit, I take no responsibility. Also there are some high voltages, so be VERY CAREFUL!

I am running this on 240V in the uk

Hope it all works for you.

thanks

Phill

I was sent 2 Burson V6 Vivid opamps in return that I made an little Review.
First of I nedeed a device to put it in,I´n my main rig I dont use opams at all.(except for the DSP)
So I thought of the old headphone amp that uses opamps.So I dug it out but it Needed a new PCB.
So I found this on the Aliiexpress.

Ok I found out it is a buffer, 2v in 2v out.But I couldnt find any other so it will do.



I listened a short while With the NE 5534 That came with the board,they sound kind of gray to me. (By the way I use Sennhizer HD650 and the Asus xonar essence).

hi there,

I am currently working on a ATC SCM100A clone.
I've got everything sorted except tweeters.

I am torn between Seas T25CF001 (which ATC originally used in their line before they started making and using their own tweeters)
or a Seas 27TBCD/GB-DXT
(http://www.seas.no/images/stories/prestige/pdfdatasheet/H1499_27TBCD_GB-DXT_Datasheet.pdf)

The latter one has a waveguid and hence I expect better dispertion and I know this tweeter from Grimm and Kii Three speakers, which I both really like.
The T25CF001 however was originally used by ATC .. BUT it used ferrofluid!
I really don't like ferrofluid tweeters as the ferrofluid can dry out over the years and change its frequency-response.

So any suggestions?

Further I was wondering if anybody here has seen a original ATC SCM100Asl from the inside.
Since its a ported cabinet design I wouldn't know how to dampen the inside correctly.
Well I guess bitumen and/or eggfoam to all plain surfaces, for sure.
But then should I also fill the whole void with wool?
What do you suggest?

Thanks in advance

I'm looking for a component that burned trough on my Icepower 125asx2.
I think it's a surge protector from looking around but i'm not sure.
It's between phase in and the fuse (see attachments).

I hope you guys can help me!

β-help current mirror



















https://picx.zhimg.com/70/v2-2ab794...051aa_1440w.avis?source=172ae18b&biz_tag=Post

Hi,

First of all. This NOT a thread with a Open baffle mid and Bass reflex bass. Now that we got that out of the way. Let me elaborate on it.

I was toying around with a concept that I thought off. For an OB woofer, one of the challenges quite often faced by the design is the gradual roll of at 100+ hz, unless you have a 2m wide baffle. So getting low end bass ~30Hz is a challenge. The benefit of OB baffle bass is there is no radial emittance therefore reducing room interactions. The common way to do it is to just boost it like crazy via a graphic equalizer or DSP or some other active means, or via the crossover. My proposal is to use a bass reflex system but in a wrong way.

In a bass reflex system, the port tuning is normally quite low, circa 30-50Hz for a large woofer, That is because the bass reflex design only works above the port tuning frequency. Below the port tuning frequency, the port output becomes antiphase with the woofer and cancels it instead of aiding it. To make it worse the back pressure on the cone becomes negative and the cone starts to go on extreme excursion with just a little power. This is the negative part of BR, but it could be used to our advantage in a OB.

The design calls for a normal practical OB, (circa 2 feet) or U/H frame. It will have a seriously undersized box for the woofer with a very large diameter short port to achieve of port tuning frequency of 150Hz or higher. Therefore the Woofer is actually in a negative backpressure region as compared to an OB which is a zero pressure region. This will be coupled to a midwoofer/full range WAW/FAST system crossing at about 150Hz. The port will be emitting a out of phase signal similar to the back of a woofer. But this has a added advantage of negative back pressure on the cone.

I have done some simulation on SBP softica software on using the SB Audience Bianco 150B350 Open baffle in a 20L box with an 8inch diameter 6 cm length port and this is what I got. There is an approximate 40% increase in excursion at 20Hz compared to a OB. I simulated OB excursion by using a ridiculously large box as a sealed system.

The file Hybrid Frequency response is what the simulated frequency response of the system as a bass reflex which looks ridiculous of course because there is no baffle consideration.

The file Hybrid excursion and OB excursion displays the excursion under same electrical conditions of 20W.

I would like your thoughs and feedback on this...

Thanks.

Oon

Is there anyone out there who has actually built a pair of cabinets to house the Seas A26 kit sold by Madisond Sound?

There are two drawings on the Madisond web site, and they give different dimensions. I would like to be certain before I cut wood. I know that I shouldn't cut the baffle/motor board before I have the actual drivers in hand, but even so, there should be some consistent plans.

Thanks in advance for your help!

March 14, 2014 - United Silicon Carbide Inc. releases Best In Class 1200V SiC JFET Transistor
United Silicon Carbide Inc. (USCi), releases its portfolio of 1200V Silicon Carbide JFET product in die form and TO247 packages. The breakthrough United Silicon Carbide xJ series of 1200V JFET's are the industry's lowest RDS(on) SiC transistor device. This market milestone for silicon carbide enables best in class converter and inverter system efficiency through incorporating the lowest figure of merit ( FOM) switch commercially available. The depletion mode xJ JFET series takes advantage of silicon carbide's significantly superior performance over silicon, offering the user the best wide bandgap switch at standard 175°C Tj max. When appropriately packaged, the xJ series is capable of operating at temperatures of 250°C and beyond.

Designed to achieve best in class system efficiency, improved thermal characteristics and industry leading FOM – the xJ series enable the most efficient switching solutions for both power discrete and power module applications.

United Silicon Carbide - USCi News



and also: CoolSiC? 1200V SiC JFET & Direct Drive Technology - Infineon Technologies

Hi,

I have to fix our broken microwave oven. I opened it and found a shorted capacitor. Anyway, I also found a rather weird magnetron HV supply, it's basic circuitry is like the one given in the German Wikipedia:



Translation: Netz = mains, Heizung = heater, Gehäuse/Erdung = ground.

Using the same components, I would have expected the capacitor in parallel with the magnetron and the diode between the transformer and the magnetron/capacitor. I'm lost now and don't have any clue how the arrangement works, as the magnetron basically is a diode wired in antiparallel with the SS one.

Another question: How critical is the capacitance value? The defective one in our oven is 0.87 µF, but I only find either 0.85 or 0.9 µF capacitors. Which one should I chose as the replacement?

Best regards!

Does anyone know the value of R41 resistor? I am replacing burnt resistors and this one is burnt beyond recognition.

So I got a question as I think there's either something wrong with my measurements or my understanding of crossovers and alignment.

I currently use 2 Jbell SS15 subs with an MKH 130 on top and Spl runt copies on top per side.

Sadly I can currently only measure in room.

My steps were:

1. Set main system target
2. Set individual targets for the individual speakers
3. Set crossovers to follow my desired targets.
4. Now some weird things happen:
I used asymmetrical crossovers. for example SS15 -> low pass 85hz 18db Butterworth to meet the MKH130 which was high passed at 80hz Linkwitz Riley 24db
5. so far so good, they meet my target...
6. I used sub align to verify the point where I should place my mic for an even distribution of phase shift. (but in a 5m long room, there wasn't very much difference)
7. weird thing is: they time and phase align perfectly without using any delay.... did my crossovers shift the phase in a certain way so that the 2 speakers got time and phase aligned by simply using specific crossovers? or am I measuring it wrong.
9. After that I tried using different crossover settings and now the mkh130 needs some delay to match phase with the SS15.

I also did a A/B listening test and couldn't really tell any difference, but also the room is pretty bad, without any acoustic treatment for bass.

My main question is: could it possibly be that those specific crossover settings just "work" without any delay or should I try measuring the whole thing outside to verify?

Thanks in advance
Johannes

Faital 3FE22 TWS 1mm wall

Wanted a super lightweight stereo speaker pair for travel because as we all know those bluetooth boomboxes are an abomination, okay some sound pretty good considering the size, but you can’t beat a stereo source, no matter how much fancy reverb algorithm you throw at it.

And so it came to pass, Red translucent PETG, okay so 1mm wall is not strictly true, there are 15mm ribs, but the result is a 1.8L 200g vented box, F3 95Hz.

Together with the Faital 3FE22 driver, and 12v power tool battery 220g, comes in at ~3 pounds for the pair.

This is my first experience with the 3Fe22, and man what a beast, completely amazed by the clean rich powerful sound coming from them.

First version had the traditional hole in the cabinet, and was going to work out later what sort of grill I was going to mount on the outside, and then duh, just integrate it into the design.

Lined with Melamine cleaning sponge from Daiso, because that’s the only open cell foam I had in the house, and works brilliantly, I bet it’s what Marie Kondo uses in her speakers.

Amp is the Aiyima true wireless stereo module, it sounds really excellent.

The only addition is a power switch and a volt meter, because this PETG is translucent I didn’t have to make a window for it.

And here in action on a beach on an island with Bali in the background.

DX7 Pro is a balanced DAC and headphone amplifier/stereo preamp. I would like $350 plus shipping and fees. Minty condition with all accessories etc. included.

Topping Pre90 is a balanced preamplifier. It is the most transparent preamplifier I've ever come across. My dad's PS Audio Gain Cell, (which we sold after buying this) sounded embarrassingly sterile and dull compared to the Pre90. I'd like to get $400 plus shipping and fees. Even at its $600 retail price, I don't think anything compares. Cables, remote, etc. all included. Unit is in mint condition.

I've had a couple of transformers that just don't fit most if the amp/preamps I want to build. They are R core 30va with 24v secondaries. I've no idea when I bought them or why.

I know its less than ideal but other than heat, what would be the harm in dumping some of the excess power if it can be done? For example Im building Wayne's BA 2018 line stage and am aiming for +/- 18-22v. 24v secondaries means roughly 33.6v rectified. In a LM317/337 set up could I lose the excess 11.6v. And how would this be done?
Alternatively what projects could use these transformers?

Yours,

An electrically challenged novice

We have published before, and also recently, the DAO circlotron headphone amplifier built by NicMac.
https://www.diyaudio.com/community/...a-zgf-headphone-amplifier.225577/post-7325913
This really have exceptional performace without applying any global negative feedback.
So why not a power amp version ?

For the last 2 years during Covid 19, we have been working quietly on a circlotron power buffer for loudspeakers.
It takes the same idea of the LU1014 Triode Cell from the Zen Variation 9, but is different in that the LU1014 is used in follower mode.
How that can be done, and how the challenges have been overcome, will be explained here.

To start with a family photo.




Patrick

This is probably more of a physics question but it has me wondering. I bought this handy metal bracket for mounting TO-3 transistors to bigger heatsink. It's about 1/8" (0.125) thick. Would moving up to the next size give much of an advantage? Say the same thing but made from 3/16" (0.187) thick aluminum. Thanks.

Hi !
I need help with changing the clock of Pioneer DV300 with more precise one but I do not have any experience with that. I use it like CD transport and I really like it how it performs.
As an attachment I upload the service manual of Pioneer DV300.
I would like to use the one in the following link which promises to be quite good:

https://www.aliexpress.com/item/330...!sea!BG!1854486564&curPageLogUid=SijbBkbFptSo

But may be I choose a wrong one. .., Please any one if can help me ..

Thank you in advance !

I have an old Heathkit AA-1800 power amp. This is a beast of an amp, rated at 250v per channel. Since this is almost 40 years old, I'm thinking that it might be a good idea to replace the capacitors in the power supply. There are two 13,000 uF capacitors, rated at 100v. The outputs from the power supply are + and - 100 volts, which seems way too close to the output - which actually measures slightly higher than 100 v. Unfortunately, it isn't easy to find electrolytic capacitors at this size, and voltage ratings seem to be 100v or 200v, with nothing in between. Is going with 100v replacements too risky?

Just begun building my SSE amplifier.

Using 360-0-360 @0.4amps, 2x6.3v @ 4a, 1x5v @ 4amps transformer from 230v at 50hz.

Here we have a steady 240v AC supply here rather than 230v so I guess that'll increase the output a bit to 375-0-375

SSE OPTs (not push pull) at 5k with taps @ 1.5k/3.5k so hopefully I can utilise UL

100uf run capacitor

5h choke impedance somewhere between 50-100 ohms - not arrived yet so unsure. Does the impedance matter?

Planning on having independent volume controls for each channel to allow balancing of tubed if they are not matched well.

EL34's for output valves, just cheapies from China initially.

Free software would be nice.
Ability to adjust font line thickness
Many font choices
Export the vector files

I'm using sketchup Layout for 30 day free trial but the absence of a protractor is driving me crazy

Here they are.

Why don't manufacturers publish T/S parameters for cheap drivers? My theory is that you guys will cross-reference the data and discover that your $200 woofer is available for $10 on Alibaba under a different brand name.
This **** has been going on for years. I used to work in a parts department. Ask for Fiat front brakes we'd charge you £10. Ask for Ferrari rear brakes (same part #) we'd charge you 10x as much. Same with all Bosch parts. Ford headlight: £25 BMW headlight (same part #) £80. Morris Marina door handle: £40. Lotus door handle (same part #) - your first born!

I built a Peppy Player with Monet and a HiFiBerry and 7" RPi touchscreen. Works great! I would, however, like to remove the HiFiBerry and connect the line output to my stereo. I removed the HiFiBerry and changed the config.txt [volume.control] amixer.control from Digital to Headphone but nothing comes from the 3.5mm line output jack. What else must I change to get this to work. (The line output worked before I added the HiFiBerry but I don't remember if I changed anything else.)

Hi,

I'm new to this site and wanna ask for some advice on building my 5th portable speaker.

I was looking to build a portable speaker in a ammunition box, with a wondom jab3+ and a 4s2p battery and a inlay of wood (for stability). I was wondering what drivers to use in it 4,5l internal volume without the drivers. For playing inside aswell as outside.

I was thinking about 3 options:
1:A dual tcp115 vented design with dual tweeters(any sugestions?).
2:A dual tcp115 sealed design with dual tweeters(any sugestions?).
3:A single tcp115 vented design and a sealed 3 inch full range driver.

Let me know what u think!

Thanks in advance,

Martijn

?

Hi!! Who can share the scheme? Tube amplbfier PP 6FW5
ideal innovation ELITE 40!!I can't find on the Internet!

Hello!

I was looking through the internet depths and found this website https://freeloudspeakerplan.rf.gd/
I saw this , and a question arose - how to calculate the angle at which the H4 sticks out and extends the horn if it is flat on the ground? and also the angle where the orange meets the blue part.

Thanks,
August

What compatible tube will lower the gain of an EAR 834p?

I am (deaperately) looking for an internal ribbon cable or better to say, for the socket and the fixation of the ribbon cable in the socket. The fixation is broken.

I just need the name or, even better, a part number and a source.

18 Pins, 1 mm

Hello,

Is there a crossfeed end-all solution?

I dont care if its a plugin or hardware.

Chasing 1 X power Quad 989 main transformer. Please let me know if you have one for sale. see attached photo.

Hi,

Does anyone happen to see this thing? I have 3 pcs of it as google finds no datasheet and where it is being used for?

I found one item on sale but its M42c-9, and also no datasheet. i don't know if its vacuum tube or somewhat related.

Before I discovered VFETs/SITs, I was a vacuum tube addict. Now I have seen the light, but some old memories are starting to resurface. More iron has been creeping into my builds, and my thoughts have been turning to transformers - interstage and output transformers.

I am very happy with my last inductor loaded VFET/SIT builds and I thoroughly enjoy listening to them, but the itch has started again. I am a serial amp builder.

I like trying new things, and luckily, a new idea came to me. I remembered that I have a pair of interstage transformers from my previous life. They were used in a 5842 tube / 45 tube amp. They are Magnequest RIT-5 (5k:5k) gapped for 50H 20mA DC if I remember correctly. I still have these monoblock amps but I haven't used them for years. I can't remember exactly when I built them, but it was 20 or 25 years ago. So, these interstage transformers will be part of my new amp design.

When I was young and into Directly Heated Triodes, I was greatly impressed with Susumu Sakuma and his Direct Heating web site. His designs with transformer coupling, power triodes as drivers, and chokes galore were eye candy to me. Sadly, he has passed away, but his ideas live on. This new VFET / SIT amp was inspired by his designs.

Having decided that I wanted to build a transformer coupled VFET / SIT amp, I researched what has been done before. I found works by Jean Hiraga, Nelson Pass, Michael Rothacher, and others. So, I'm not the first with this idea. However, my idea is a little different in that I will use a source follower output stage, and I haven't found any references to this mode - probably because engineering wise, it is wasteful. But, I'm not constrained by cost (within limits) or practicality so I can live with a voltage amp stage and an interstage transformer which would not be necessary with a common source output.

I ordered a pair of J&K Audio Design's version of the Tango FG-50S output transformer so I'm starting this new build journey. It'll take a month or two to get the transformers but meanwhile, I will build and test some prototypes with choke loaded output.

My first version will be 2SJ28 driving 2SJ28. I also have some 2SK180ES and THF-51S for outputs and some Russian 2P926B for voltage amplifier. The larger SITs will require a bigger driver voltage swing for full power; that will need some experimentation.

A couple of photos below show my breadboarded 5842 IT 45 tube amp monoblock with its LCLC power supply, interstage transformer, and output choke and parafeed transformer. The interstage transformer is shown in the last picture.

Hello all,
I've been trying to find a suitable driver for use with my Alan Eaton 45 SET amp, and have been all around the world for several weeks, first trying to go the fullrange route, ordering a pair of Liisong's new PT-10 drivers. I cancelled that order when I discovered the Radian series of coax drivers, and settled on the 5210, a 10" cone with a 1" aluminum alloy compression driver. Here is the page for it: https://cdn.shopify.com/s/files/1/0111/0324/0254/files/5210C.pdf?v=1617035289</ul>

I decided to go with the Radian because of the success some people have had with them, particularly Frank Fazzalari of Coherent Audio. His speakers win high praise and not from the usual commercial circuit. There's also a company in Germany making beautiful speakers with these same drivers.

So. I've got lots of experience building and DIY'ing including amp mod stuff, but this is my first foray into a from-scratch design/build. I think I'm in the ballpark but "the more I learn, the less I know" has never been more true. Night after night I read until it makes no sense anymore. Recently read Martin King's work on MLTL/QW theory, and learned a lot although the math was about 40 years late for me. I'm needing assistance in two areas, the crossover and the boxes.

For the boxes, I've got a pretty simple idea for a BR enclosure, 2.2cu.ft/62l, or, if I can find a way to design it, a 3.3cu.ft/93l. Both of these were generated with free online software and compared to existing enclosures. I also got a version using Eminence software through US Speaker, where I purchased the drivers.

First - I don't know whether this driver is more at home in the TQWT or the BR, but I feel that a QW pipe with a full terminus would be a better choice. I don't know all the correct terms, so by 'full terminus' I mean where the throat opening is not restricted and is a continuation of the pipe cross section as in true Voigt pipes. I'd prefer the throat to be bottom front rather than an open base, as in Troels Graveson's designs. Try as I might, I cannot find a reliable resource to design this box, and would really appreciate some help. I will even pay someone to generate the design, as I'm way behind on my work and getting behinder all the time right now. But first I'd like to know if a simple bass reflex might be as good or better, though I doubt it. I prefer the bass response of the horn, not driving a narrow band slug at the terminus then falling away.

Second - the crossovers! I've plugged the T/S numbers in every free software I can find, and the a friend and coconspirator who has a Windows rig used Jeff Bagby's crossover designer as well, and I think I'm in the general ballpark but still not sure. I will post the FR of the drivers below, as well as the tweeter response with 5uF, 10uF, and 15uF caps on the tweeter (first order). Here are my questions about the crossover:

1. Frank declined to sell me his crossovers, and wouldn't give me the values, but we had a great conversation anyway, very good guy. Although he uses first order on both drivers, he said I might want to go second order on the tweeter. I would rather avoid an inductor on the tweeter mostly due to phase concerns, which is really high on my list and part of the reason I was originally going to use full-rangers. So first gate: first or second order?

2. With first order Butterworth, I've got pretty typical values at 1200hz, 1350hz, and 1500hz: 16.56uF/1.06mH(woofer), 14.72uF/.94mH, and 13.25uF/.85mH. Second order on the tweeter only lowers the cap values a bit and adds a small inductor.

As you will see in the frequency/impedance graph for these drivers, there's a really knotty issue due to a sharp impedance spike from the tweeter at just below 800hz, and this is really interfering with the falloff of the tweeeter and pushing up the FR almost all the way to the intended xover point (I'm using 1350 as a general target). I don't know how to remedy this, and am beyond reluctant to even go to 2nd order, let alone 4th. I'd rather start from scratch with a different driver, BUT this doesn't seem to bother Frank, he's got some way of dealing with the impedance that I don't understand. Zu audio is another example of a popular speaker using cheap Eminence drivers and squeezing out very good performance. I'm guessing these guys are manipulating the enclosures to make it all work?

Below I will post the following: The Radian EQ/Imp graph, and the tweeter response for first order using 4.7, 10, and 15uF values plugged into Jeff's program. Any and all guidance is much appreciated, and like I said earlier I'm willing to pay to learn here, I wish I had a mentor in my area but there is nobody doing this. Cheers, Bryan

I APOLOGIZE FOR THE LAST TWO IMAGES BEING ROTATED, I DON'T KNOW WHY THEY LOADED THAT WAY!



With 4.7uF cap, lower green line:



With 10uF cap:



15uF:

Hi guys 🙂
I just bought a General Electric tube radio for fifteen dollars at a thrift store. It was not in great condition and the electrical cord was cut off. I opened it up, and I saw that a component looked like it was leaking. Should I replace it before turning the radio on, and if I should, what is the name of the component? (It's the little component at the bottom left.0 Thx!

So I bought a TPA3250 board to check out. I picked up a MeanWell 24V 150w switching power supply to give it juice. I was buying connectors and associated doodads and threw a EMI filter into the bag, it's this one:

https://www.amazon.com/dp/B08D3MP48W?psc=1&ref=ppx_yo2ov_dt_b_product_details

Normally I'd buy the IEC connector + filter, but this stand alone unit caught my eye. And I figured I'd put it between the wall and the SMPS. But then I thought what if I put it between the SMPS and the amp board?

So I thought I'd ask those who know more than I: Would it be beneficial to have this sort of filter between the SMPS and the switching amp?

• Does the filter care about the difference between DC and mains AC? (I think not?)
• Is the MeanWell likely to be dirty enough up high to benefit from a filter like this? (MW is a good brand, but nothing is perfect)
• is the 3250 board likely to care about a little HF power filtering? https://www.amazon.com/dp/B0B258YS3B?psc=1&ref=ppx_yo2ov_dt_b_product_details (maybe it makes enough of it's own noise internally, what's a little more?)

Thanks for your thoughts...

There is still some uncertainty with new members when they cannot PM. One example is when they sign up for Swap Meet and don't think to ask the seller to initiate the PM (not realising it is now presented in conversation form, and that they can indeed reply to them.) After discussions with member PRR, this suggestion has been put forward as one way to handle it.

I would add explaining the paging/mention system (@PRR ), the nature of the PM system and anything else that would help.
As a result of this, some post private details in public. I'm also concerned that some will needlessly give up.

This will be a very lazy building thread as I take all the time, I need to have a fun build.
PCBs will come from ZM in version with many (most) components mounted.
PSUs has also been ordered. Those will be 65V SMPS's.

Chassis has also been ordered from Modushop and a big box was in front of my door when I came home this evening (26.5 kg).
What added to the weight was the special heat spreaders to spread heat from a single device on each side of the mono block chassis.
Each chassis has 2 x 200 mm heat sinks on each side. This gives a challenge when only one device is mounted that needs both sinks.
A couple of images attached. One image shows the unpacked 10mm thick heat spreaders. Two for each chassis.






Shipment was only a few days.
Now time to think about how to mount the heat spreaders. Will have a closer look at the heat sinks to explore possibilities.
So far so good. This was the easy part just to order and spend some money!