I've always been intrigue with this method of identifying breakup modes in cone drivers.

www.sugawara-labs.co.jp/en/application_xenonflashes/direct_observation_of_speaker_cone_vibrations

When I consulted with a few independent speaker designers back in the late 80s to early 90s, we used modified ignition timing lights to check the performance of various cone geometries and materials in LF drivers to find their limitations when operating out of their designated bandwidth at higher drive levels. I got the idea from designing and testing light weight valvetrains used in high rpm race engine applications ie. Spintron testing. You'd be shocked how bad the cone of an LF cone driver deforms at higher output levels and various frequencies.

I remember KEF and B&W doing laser interferometry research many decades ago. I'm surprised this area of technology hasn't filtered down into the diy crowd yet with all the access we now have to information pertaining to speaker building.

Dad recently took a turn for the worse. And his Parkinson's has entered its final stage. He suffers from Sundown syndrome and Psychosis.
So I have been researching up on how to help.
Things we are trying.
1. Calming music, / Nature sounds
2. Guided meditation and breathing exercises.
Then I came across this short clip which says it will help. Its a regular song. But the signal bounces from one ear to the next. To me it just gave me a headache after some time. But they say it helps so I plan to try it.

I also need to look into playing special frequencies.
There are a lot of really old smart guys on this forum. Any help or ideas to help would be much appreciated.
My gut tells me Audio can help. Im just not sure how will share any info I find.

Hello all,

I have a VTL ST 85 amp that I want to upgrade the coupling caps in. The current caps are VTL branded show .33k 400V. All of the possible caps from the likes of Mundorf, Solen, Infinicap etc. seem to be labeled in microfarads or uf. If the common nomenclature for the K after the .33 is picofarads, then what is the microfarad or uf. conversion? Is it a .33uf cap? .00000033uf? Thanks in advance.

So once upon a time I used MLSSA for measurement, LEAP for enclosure simulation. I don't think I can run any of that any more, certainly not on my Macs. I'm wondering what softwares folks are using now

• For rough "put in some Thiele-Smalls and generate boxes like they are electrical circuits"
• For designing with actual response and complex impedance data like LEAP did
• Something that would let you simulate different voice coils and windings. Like SpeaD but not $1700, I just want to do some curiosity modeling. Jeez I wonder whatever happened to the Excel sheet I used to use to calculate voice coils...
• Big bonus points if someone can point me to a package that can do tone burst simulations.

I say 'maybe'.

My journey in things music- and sound-related started with singing, then playing instruments to accompany/support the singing, then much later into the tech aspects of music and sound. I have never lost sight of the fact that, while there's a large overlap in skills required to do them well, there's a huge experiential difference in playing or creating an instrument versus being one.

In the most general sense, a musician is someone who makes music. What qualifies as 'music' is a whole 'nuther matter. But it's interesting to note that singers rarely refer to themselves as musicians, unless they also play. But players almost always do.

And that's pretty much where I land. Singers are singers, and players are players. And they may or may not be musicians, except when referred to in the abstract, when they are. But the participants in the community definitely sense and make a distinction.

I've read most online opinions on wiring crossovers and crossover-to-terminal connections, but I'm about to build my crossovers for a pair of heritage-quality DIY speakers (two-way), and I'd like the opinions OF THOSE WHO BELIEVE THAT CABLES MAKE A DIFFERENCE IN AUDIO QUALITY:
1) Do you think that wire selection makes a difference in component-to-component connections in crossovers when direct component lead-to-component lead soldering is not possible? If so, do you have recommendations?
2) Do you think that wire selection makes a difference in crossover-to-speaker terminal connections when the required wire length is less than 18"? If so, do you have recommendations?
I'm not trying to be rude, but I'm not looking for answers from those who already believe that all well-built and appropriately-sized interconnects and speaker cables sound the same. In other words, I'd like to hear from those who essentially say "Yes, I think that wires make a difference, but in this case, don't worry about it," OR those who say "Yes, I think that wires make a difference, and I'd recommend you use this in a crossover..."
Thanks!

There is plenty of information on stuffing of sealed enclosures for best bass response. I have not found much information on the rationale for stuffing mid-range cone driver enclosures. Intuitively it would seem that critically damped Q = 1/sqrt(2) = 0.707 is not so important, but what are the most relevant stuffing parameters to optimise?
I assume the aim is to minimise the wave returning to the cone rear. What is the best stuffing material for this? Is there anything with significantly better performance than fibreglass? The folklore about long-fibre sheep wool advocated by A R Bailey's work on transmission lines, is based on the reduction in sound speed which increases the transmission line effective acoustic length. I don't see this as relevant to sealed mid-range enclosures.
Are the recommended stuffing densities for sealed bass enclosures appropriate for sealed mid-range enclosures?
Is it possible to overstuff a mid-range enclosure? What are the audible effects?
I would appreciate links to serious articles on these questions.

A friend and I got into a debate about what a 'digital signal, sent over-the-air, as in when receiving OTA HDTV from broadcast towers' appears like electrically. Pardon me if this isn't the best place to ask but it does apply to music too and I thought solid state amplifiers would be suitable.

The friend said that the 'digital signal', where his understanding was that the digital signal was that of a square wave, was 'perfect' and meaning in its 'squareness and exactly SHARP corners'. The signal was never, ever 'in-between' and only always exactly electrically representing a '0' or a '1'.

I argued that there is no way possible to create an absolutely perfect square wave signal, which would represent 0's and 1's, because there is always a bit of overshoot on the, say, on the 'way up', and then some over compensation resulting in a bit of undershoot, and that repeats but that signal does quickly 'level off' at the 'flat top' which is supposed to be there.

My argument was based on the fact that NOTHING, except only in the realm of mathematics perhaps, when in the real world, can go from say '0 volts to 1 volt' instantaneously and without any over and/or undershoot before it settles to its 'correct/wanted' amount/voltage/etc. So, therefore, my argument was that even broadcast 'square waves' cannot possibly be 'perfectly digital' (in his vision of the signal) which he thought was so.

And, furthermore, there isn't anything such as a 'digital antenna' which are named that and sold with those words. Maybe that was his problem with me arguing the topic because he had bought a whole new $100+ 'digital antenna' when then I showed him a few minutes later on that a simple piece of wire could receive the signal just fine as it did with the former NTSC broadcast signal (which everyone called 'analog television' or something like that).

Which of us is correct? I am curious.
Thanks!

These Akai M8 chassis have been stripped and rebuilt with RH84 circuits AND 12B4 preamps. For the uninitiated, the M8 reel to reel has pretty good parts--a nice PT, a choke in the PS, and OPTs that I think are as good as the much more celebrated Sony 500a transformers. I used solid state rectification, and with that, the PTs do not run hot.

While the RH84 doesn't need a pre, the 12B4 is included here so it can drive sub amps easily (or a DSP or SS woofer amps for biamped OB setups). This 12B4 implementation uses a CCS on the plate and LED bias. I think there is a little cap on the sub output that I used as part of the low pass. Or maybe that is switchable? You'll have to check.

There are parts throughout that are too fancy. You'll notice some nice caps . Film caps for coupling, including a motor run after the pre. Snubbers on the rectifiers, etc. PEC pots for the main volume. All relatively low hours.

These worked last time I used them, but they have a little extra noise (an intermittent crackle--actually very little hum, even on efficient speakers). My theory is that the layout isn't ideal (I'm sure most folks here will agree). I think they'd work better if the two bits are separated. In other words, maybe pull the 12B4 preamps out and put them in a separate chassis with a separate power transformer. Or, at least revise the grounding layout.

This is like two good projects in one, and better than starting with a stock M8. Stripping them down to rebuild took longer than I anticipated as Akai used A LOT of solder. But, I have more projects than time and space, so I think these deserve a new home. They'll come with a full complement of tubes.

I did this awhile ago, so you'll have to figure out how to hook them up and use them (which jack is which, etc). I obviously goofed with the chassis set up a bit to add fuses, switches, jacks, etc as needed. But, I think the preamp circuit is very straight forward (aside from the CCS) and the RH84 follows the schematic.

I'd save these to pilfer for parts, but taking them apart seems sad. $160 +shipping. I can negotiate a bit, especially for a budding DIYer. I don't really need more projects in trade, but I'd consider interesting DACs and streamers.

Paul

Hello,
looking for a nice assembled DDDAC ( PCM1794 x 4 stacks) , Thanks!

As some members might already know, I use an IQaudIO DAC HAT PRO which is producing intermittently audio artifacts. During boot, a short beep-like sound is emitted. This beep-like sound is also emitted intermittently during audio playback. I would like to know whether this issue is caused by software or caused by hardware failure.

Hello,
Someone have service manual of Alpine CDE-7826R? i don't found..

Hello, who collected the Apex a17? assembled this amplifier, there is self-excitation how to eliminate it?

I am looking to add some bass to a small 2.1 bluetooth project. I am going to use the amp listed below

TPS3116D2 Class D 2.1 Bluetooth 5.0 Amplifier Board 2 x 50W + 100W with Filter and Volume Controls

I have mids and highs but need to add bass driver for the .1 channel. Looking for clean sound, nice extension down to about 60hz range and something that wont break the bank. Needs to be small cabinet size of about 0.30cu.ft. (so 0.15 each if using 2 drivers) I would like to stick with ordering from Parts Express if possible...they have always been great.

Unless somebody knows of a super small enclosure 6.5", I am looking at 5.25" drivers. I saw the Tang Band below on a $20 open box special, but they disappeared and sold out.

Tang Band W5-1138SMF 5-1/4" Paper Cone Subwoofer Speaker

Then I saw these Peerless and thought they looked great. For $43 I can get two of them and would be the same price as a single TB

Peerless by Tymphany SDS-135F25CP02-04 5-1/4" Paper Cone Woofer

1-Has anybody used these and can give feedback?
2-TB seems to extend so much lower than Peerless. Even ported the Peerless seems not to go that deep...why?
3-I prefer the simplicity of sealed, but in sealed the Peerless F3 of 114hz seems ridiculously high. Do I need to just break down and make ported?
4-If ported, has anybody used the Peerless and willing to share box and port dimensions.

Thanks

Broke Down and bought the Seas L15RLY/P-04 5" Thought there would be plenty of Designs that would tackle the Cone break but not so As you can see this is a Production run of the never offered (to the Public ) 4 OHM version of the speaker there is a break up around 8K that looks nasty, very similar to the 8 OHM version THE question is Can the FIX applied to the 8OHM version be applied to this driver with Minimal Tweaks ( Value Adjustments )

I don't want to go active Crossover looking for a little Guidance as I don't have a clue If you are wondering I also Picked up the
27TDFNC/GW (H1462) 1" to pair with it (upon Recommendation ) Buy the way still on sale at Madisound anyway any help would be appreciated Thanks in advance Steve

Hello,

Just got my first amp with OTs going after some troubleshooting. First tried it with my crappy testing phones and it seemed alright, about as tinny as I'd expect from 1¢ phones from a 1¢ source, so I tried my HD558s with my phone as the input and it's still just as bad.

Sounds like a high-pass filter basically, no bass what so ever compared to plugging the phones into my phone.

There are no coupling caps so all I have left to suspect are dumb mistakes, the core design, the tubes(?) and the OTs.

This is the schematic I based my build on:
http://diyaudioprojects.com/Tubes/6DJ8-Tube-Headphone-Amp/

I did not use the transformer or PSU specified because I had some small OTs I have characterised and found fairly suitable in the lab, with 0dB @1kHz the -3dB span was about 100Hz-40kHz if the levels were in the 100mV range on the secondary.

As for the PSU, I wound my own power transformer, used a bridge rectifier and then 440uF + small poly cap for the reservoir and a 1.7kOhm resistor into another 440uF + small poly cap for the B+. (what's the deal with tube PSUs always using caps <=100uF, we're not in 1950 anymore)

The heaters are AC for longevity, +-3.15V around ground.

The ECC88s i have installed seem like new production ones, they don't look particularly well made honestly but they seem to function alright. I don't have any known NOS ones but I do have more ECC88s in my collection I could swap in.

I also started looking at the specs of the tube and the load line and well, the schematic as drawn and what I've built both exceed power and voltage limits, especially as designed with 32 ohm headphones it seems all sorts of bad.

Tl:dr:

Built basically this amp:
http://diyaudioprojects.com/Tubes/6DJ8-Tube-Headphone-Amp/
But with a different OT and PSU, there is no bass when playing music. Sounds like I've made a high-pass filter but there are no coupling caps in the signal path. Any ideas what to suspect?

Have you guys noticed that Audiomatica has released a new measurement package, the Clio-12 . It has a USB interface for the PC ....finally.
Was always hearing about problems with the older Firewire interface.

Has anyone seen this unit so far ? This must be basically a Clio-11 with a USB interface instead of the Firewire interface?

For sale verry good and nice sounding dac from mr. Manunta from Italy. The Dac is like new and till October 2024 in warranty. With original package and all parts. Price would be 650 euro or best offer. Payment thru paypal. Shipping is included inside EU, outside plese ask!!!

Hi Guys,

I just purchased some Audiomaster speakers (they were advertised as MLS1), but I am unsure as to what model they are, ie Audiomaster MLS1 or MLS2.

I have searched the web, but not much info on these.

I have included some pictures and would be really grateful if some can identify them please.

Many thanks

Hi all,

I have designed a PCB for the TPA3255 based on the given schematic in the datasheet without PFFB for stereo BTL mode - attached is my design. I've included a microcontroller to monitor the supply rails and bring the TPA3255 out of reset once the supply rails have stabilised.

Once the TPA3255 comes out of reset I see a large amount of oscillation at 50kHz around 16Vpp with and without a load attached (I've tried open circuit, 4R, 8R resistors and a 4R speaker). Does anyone know what could be the cause of this? Particular types of inductors or capacitors in the output filter? Is there any feedback in the system when no PFFB is used? I'm struggling to find anyone else with this problem and not sure where to start really.

Many thanks,
Boscoe

Hi,

I am searching for 112A tubes to buy.

https://www.radiomuseum.org/tubes/tube_112a.html

Preferably in Europe. Contact me.

Thanks

Hope everyone had a good Christmas 😉

I have been looking how to calculate balancing resistors for a power supply using 2 capacitors in series. I found this article which seems very comprehensive, and wondered if anyone has any other opinions on the magic equation that might be used without knowing or measuring leakage current on the capacitors in use.

Thanks!

Hallo, i'm pleasure be with you.

Hi everyone.
Can you recommend a cheap audio DVD player with good sturdy mechanics? no more than €60.
vintage is fine too

This is our interpretation of Nelson's original concept first published in 2010 :
http://www.diyaudio.com/forums/pass-labs/153030-semisouth-jfets-what-they-good-3.html#post2178227

Such a simply but nice concept, that it seems a waste not to make some use of it. 🙂
As an exception, we have included the Spice file so that you can play with different parameters.


Happy New Year,
Patrick

.

Hello friends
A long time ago, I had the occasion to listen to (a part of) a Jimi hendrix record which was completely new to me: very calm and very fine (and listenable…). As far as I remember, it was him alone, and it certainly was instrumental (no vocals).
I unfortunately did not ask what album/recording that was and the person who had it has disappeared.
Does anyone know of something that could fit this very vague description?

Hi
I have acquired an Oracle Premier turntable and while it is nearly complete the much needed control box for the motor is missing.
If anyone has useful knowledge of the operation of this motor it would be greatly appreciated.
I am aware of after-market options but I would prefer to try to get the original motor operational.
Here is a pic of the motor disassembled, the only component inside the motor aside from windings and permanent magnet is what looks to be an SMD device with 4 connections.
I believe the motor was made by Papst, the circuit board # in the motor is 6027 013 000.
Cheers
Kevin

Happy New Year all

I am looking at fixing a solid state GK bass amp that some fool blew when he was young and foolish.

The bias pot burned out (along with a couple transistors), so I will have to replace it and bias the amp. I won't find this exact pot, but I guess it is 1k.

But my, ahem, experience is that if the bias setting is even slightly off for a second it can blow up the amp. What is the procedure for setting bias? Is it safer to dial the pot down to the minimum first and slowly dial up? Is there a way to calculate the expected right resistance value of the pot so that it's pretty close to right to begin with?

The attached schemo says it should be adjusted for "10mv across r21 & r24."

Any tips on the right practice would be helpful - the theory will be over my head.

I'm thinking about designing a electronic speed control for my Thorens turntable. Power supply similar like Project speed control.

I'm in 50 hz country. So the power supply should first lover the line voltage to 16V. 16V 50 hz is 33 rpm.

But I have no idea what components could rise the frequency to achieve 45 rpm.

Nice article here from Time on the semi shortage

Can We Fix the Semiconductor Shortage in the U.S.? | Time

Good to see the wider world is waking up to the fact that they only enjoy their modern life because of this stuff

🙂

Hello, I just recently purchased a pair of monoblock IRD MD-100 amps for $200 locally from a girl that just wanted to get rid of them and couldn’t demo, but said she could refund me if I ran into any problems.

I brought them home and I realized no sound on one amp and the audio device was completely blown. It appears the circuitry is very simple on this and I figured it to just be a bad TDA7294.

I plan to replace it but curious if this is a direct replacement and if I would need to replace on both amps to match. Any other upgrades or modifications I could do?

The girl did offer to give me $100 back for my troubles.

Leader LAG-120B sine generator and Leader LMV-181A ac millivoltmeter $60 each, $100 for both. Cosmetically not perfect, ask for photos.

Hey guys, I’ve floated around here for a while and have learned a lot from you guys. However I haven’t come across the pros and cons to the driver placement for an mtm like in the drawing I attached. Is there any benefit to having the midrange drivers close together and the tweeter in between off to the side?

Side note: The drivers are the Satori MW19P-8 7.5” for the midrange, and the SB Acoustics SB29BNC-C000-4 29mm Beryllium dome tweeter.

Thank you guys!

Have you looked at...

the Arnold Klayman patent? US # 3 047 090. The second drawing in this patent is especially interesting as Klayman uses a simple but very clever idea to build two lines into one box and manages to load not only the fundamental but also the first harmonic of his 1/4 wave line. Regards Moray James.

Looking for a set of the Rod Coleman shunt cascode pcb kits. He is out of stock right now so if you have a set to sell please let me know.

SMPSs are used more & more in audio power amplifiers these days.

I hear that even the best of them do not apparently last more than 5 years (is this really true ?).

How can I immortalize one to run into 20 or so years (replace all caps with better and higher temp caps) ?

Hi.
I've been sitting on repairing these Jensen LS 2b Loudspeakers for awhile & decided to make a start.
When they were given to me the foam on the woofers had turned to dust.
Also the speaker terminal bracket/spades was pulled off tearing the hair thin wires feeding the cone.
I successfully re foamed the woofers yesterday.
To do this I sliced off the dust caps so I could place strips in the voice coil gap to make sure the voice coil was centred.
Today I re glued the dust caps, and doped the cones with a thin coating of Mod Podge.
While apart I noticed these have 3.7μF electrolytic caps (fixed to the rear terminal pane) which service the tweeters.

Do you think I'll be able to get away with 2 x 2μF electrolytic caps in parallel per speaker?

What would an extra 0.3μF tend to do to the reproduction of a Tweeter?

Also, although these are sealed boxes (not ported), there is only a thin layer of acoustic material lining the rear of each box.
Should I fully stuff these boxes with material?

thanks

For sale little used reference cable from Chord UK. In top condition with original package.I buyed this by Die Nadel in Germany for 449 euro. 2 x 1 meter lenght. The last version of this top cable. Price 160 euro plus 12, 90 euro shipping in EU.

Please PM me if any available!
Thanks O.B.

Interesting application of a speaker here.

https://www.pv-magazine.com/2023/01...acoustic-heat-pump-produces-water-up-to-80-c/

Hello!

So I made an attempt to run the subs I built in parallel. Both subs have a input speakon connector (4 poles for all connectors) and a "thru" connector. I have attached a picture on how this connector dish is wired. Each sub would run on its own channel, but when putting a speakon jumper from the "thru" connector to the input connector on the separate sub only the primary sub would play.

To summarize the connections. Input connectors have piggyback connectors on both the +1 and -1 terminals (both subs). The piggy backs go to the positive and negative of the driver and the positive and negative on the #1 terminals of the "thru" speakon connector. Picture below.

What am I doing wrong here?

I'm in the process of building kitchen cabinets and I decided to take a punt on a new European plywood product for the carcasses. The decision was easier with the current paucity of baltic birch. The Euro "ecoply" is made with what is supposed to be more human environmentally friendly glues (no formaldehyde and fewer organic volatiles). Interesting stuff, as it is obviously high-quality and void free.

The version I'm using has a poplar core and maple face, making it rather light, both in colour and weight (for a sheet of the 18mm that I'm using).

Might be useful for speaker boxes. I'll put it to the test if I have any leftover from the kitchen reno.

Like new, verry little use in original packing in 2 x 1 m lenght. Price 150 euro plus 7,90 euro shipping inside EU.
Verry good sounding cable. Payment Paypal for friends or bank transfer.

Hi all,

Been trying to get my hands on the DIYSG 1099s and MTMs for over 2 years now.. they seem to get bought out minutes after any stock is available.. and while during the pandemic I understood it might be hard.. it seems we're still not seeing any stock in at all.

I love to build things.. built a few speakers/subs in my days.. and want to build some custom but great sounding home theater speakers.. a full set.. LCR, surrounds, atmos, etc. They would all be powered by external amps and speaker wire runs.

I am looking to build two sets.. one set is for a smaller family room.. so the 1099s would be way too big. Something with a single 8, possibly a waveguide 1" or so.. but can be on par in terms of the 91 to 94db sensitivity the drivers that DIYSG uses (which I think are eminence? Not sure).

I've never heard any of the DIYSG speakers.. but they have amazing reviews.. and the HT8 and 1099s seem to be plenty loud for very large theater rooms, but more so have quality sound from what I have read rivaling much more expensive speakers.

So.. was hoping someone has found a few designs/drivers, crossover details, etc.. that have turned out amazing, but still cost a lot less. I liked the idea of the larger 1099s being about $500 a pop with wood. I'd obviously like to have something more affordable than that for smaller cabinets.

I am planning on running a 100watt to 200watt per channel amp.. talking Monoprice amps.. the big heavy ones that put out a really solid 100 to 200 watts, not a cheap thx receiver 7 channel amp in a 10lb receiver. So ideally whatever speakers that can be sourced and sound great.. can handle 100watts or so.. even though especially in a smaller room that volume is not necessary.. I like having more room.. so as to use less and not worry about blown out.. overheating, etc.

Thank you.

Blue Jeans cable argues for the case of using high-quality coax cable for stereo (analog) unbalanced interconnects or phono cable.
The stiffness issue aside, any thoughts about the uses of coax for normal (say 1m) interconnects with decent unbalanced RCA terminations?

https://www.bluejeanscable.com/store/audio/LC1-design-notes.htm

Hi all!
I happen to have an Altec Lansing 515E and want to build an enclosure for it. Vented? sealed?
I'd like a smooth response for listening to music at no more than 85dBc.
The sub will sit near my Kef speakers whose frequency response (-3dB) low end sits at 54Hz

quick info about the Altec 515E (http://alteclansingunofficial.nlenet.net/Thiele-Small.html)

Xmax inch 0.18
Xmax mm 4.572
Re (ohm) 12
Vd (cubic inches) 23
Vd (liter) 0.377
Fs (Hz) 22.90
Vas (cubic feet) 23.50
Vas (liter) 665.446
Ref % 4
Qts 0.19
Qms 7.50
Qes 0.19

WinISD tell me an EBP of 120,53

thank you very much

Hi I have been building and experimenting with various configurations of a two way speaker. I also tested various three way designs and found that I prefer the sonic response and simplicity of a two way speaker to a three way for my home listening purposes at midfield distance and volume. The speaker I have settled on for now is a single 15 inch woofer crossed at 700hz and a 1.4 inch compression driver mounted to a wave guide. I would like to expand the low frequency section to either two 15 inch woofers or four 12 inch woofers. Is there an advantage to the four 12s over the two 15s with regards to bass and mid frequency response given the 700hz crossover point? Thanks.

Jay

the best for 2023 to Diya members, may the peace be with you

I am wondering about the cone material sound signature of some midrange units. Of course, all things being equals, i.e layout, designer's talent, etc. At the end, a driver must be chosen.

Kevlar is often talked for its neutrality, known as far I remember since the 80s. I do not remember the Focal and Davis sound of those days, never heard the yellows ScanSpeak, but B&W is known for good ones in the 800 series and cheaper models too.

I liked the Seas Excell woven composit midwoofer (woven plastic à la Discovery SS line) ? Peereless silver serie with its glass fiber, as wavecore with its odd glass fibers non woven cone are all said very good. Ok cone material is not alone in the driver sound but its sounding signature is often particular.

What your experiences over more classic euphonic paper cones for instance. I was lurking on drivers I can affoard for my budget midwoofer for a short 250 hz to 1100/1500 hz app. with a 6"-ish size and due to average budget several ref are appealing me for that midwoofer task with minimum 90/91 2.83V sensivity:


https://dibirama.altervista.org/hom...p-6-108pro-mid-woofer-6-5-8-ohm-150-wmax.html (carbon composit. woved ?)

https://www.bmsspeakers.com/index.php-314.html?id=5s117_curves0 (paper cone)

and a less modern challenger but 8" pro mid (certainly more difficult for passive filter newbie to tame the upper range) https://dibirama.altervista.org/hom...udax-hm210z10-mid-range-8-8-ohm-240-wmax.html

There are 2 papers with PHL Audio and BMS : pro but low THD

The Kartesian LOM seems modern with interresting T&S : low Qts and low mechanical loss, certainly detailled... but that old woven cone is less tempting than fiber glass !

I wanted to put a more expensive Wavecore with its glass fiber cone, but 4 ohms is too much lowish impedance to reach the 90 to 91 dB sensivity needed to handle some baffle step compensation.

Any though please ? Is it just euphonic paper VS colder Composit or not important and better to focus on the H3/H5 harmonics and T&S parameters as well as datasheet magnitude.

Thanks

Hello,

I just found out this week that my 211 SE tube amp is 25 years old. It sounds so good I never want to get rid of it. This amp generates a fair amount of heat and is a nice heater in the winter. But heat and age eventually wear components down. What are the most likely components I should look into replacing in this amplifier? I have already replaced some wire wound resistors that had a glazed look to them. There are some electrolyte capacitors in the tube circuit, and film capacitors as well. The big power supply has 6 transformers, 4 chokes, Diode rectifiers, some very big solen film caps and two Agastat delay timer tubes? for the turn on sequence at power on.

Im new here and am looking for a reputable repair person to work on a number of my Hifonics VII amps I've saved from the early 90's. If anyone can refer me to this person please respond.

I've just bought a Fosi Audio BT10A. It works straight out of the box but seems to have a fairly severe bass cut built in to it. I'm using it with some quater wave speakers with a decent bass response and there's just no oomph below 100 Hz. Is this a characteristic of the BT10A or is it a limitation of bluetooth? I've never used a BT amp before.

My second question is, is there a fix? I'm an electronics engineer so if there's a simple mod with a soldering iron, I'm all ears. Sadly, I suspect it's all done in software.

Edit to say it is fine when using the aux in, it is just bluetooth that has a high pass filter.

I made this post on a thread that was way off track on a different forum, I couldn't find the right forum so I will try here, maybe a moderator can move it the correct forum.

There was a post that stated the room followed by the speakers as the biggest influence on the sound stage and imagining if I actually understand what those terms mean. But there was mention of what creates these things being an allusion that our brains create. It seems this part was passed over very quickly but I find incredibly interesting for personal reasons.

I only realized that my brain worked differently than most people I know in the last few years, actually I knew it, but I didn't understand how it is different. By asking everyone I know a simple question I figured it, "Do you see a picture in your mind when you think of something?" Their answers surprised me and my answer startled everyone, I don't don't see any pictures and every one I spoke to did. They asked what do I see? Nothing, I just think about the object, face or what ever. This thread made me look at this more and what I have (actually what I am) is called aphantasia and about 2% of the population have it.

Why I bring this up here is it turns out to be more than a lack of "Mind's Eye" it goes to all senses. Reading about it revealed to me that I don't have a voice in my head either and the other 98% hear their own voice when they think.

Finally I will get to my point, for the last 50 years I have been buying audio equipment, placing speakers try to get the promised 3D sound with little or no results, so I think that my brain is incapable of building the illusion. I don't know if this true or not, but I would be interested to find out if anybody reading this is the same as me. Don't get me wrong, being wired like this is fine with me, I have been thinking circles around my peers all my life and look at this as a gift, not a handicap. It would be great if I could experience reproduced sound like everyone else, but I still enjoy what I hear, but a lot of descriptions I read about others experiences have always left me wondering. My theory now is my aphantasia also prevents me form building the 3D illusion that stereo depends on.

Hi I’m new to building speakers so I have a lot to learn….( go easy)
I’ve been lurking and checking out some drivers

Beyma tpl-150/H
Dayton pro Amt

18sound 8nmb420
Ae TD8M
Ae TD10M

Have been catching my eye, I’ve even glanced over the TD12M and Beyma 12p80nd…

Now I guess as Always it’s a set of trade offs with a speaker build
So I want to hit the best middle ground, 12s and even 10s may have a waf problem in my room and also beaming seems a issue

So my gut says 8” maybe the sweet spot, I have td15h+ as stereo subs so it will be a 2way build / 3 way in separate cabinets

Any opinions on the best matching drivers I’ve mentioned or other better options would be appreciated

https://headwizememorial.wordpress....e-ended-otl-amplifier-for-dynamic-headphones/ I'm interested in building this amplifier, but I'm unsure of the power supply circuit. The transformers are quite expensive and aren't readily available in europe. Is there an alternative power supply I could use? Is any 150vdc power supply suitable

I would like to build these in a larger floorstanding cabinet. Can you advise on the larger internal volume range I could use, how much internal stuffing to use (if any), and sealed or aperiodic? I'm a "newbie" on speaker design. A search didn't bring up any precise hits on this. Thanks

http://seas.no/index.php?option=com...eas-a26-kit&catid=66:seas-diy-kits&Itemid=250

http://seas.no/index.php?option=com...6re4&catid=44:utv-prestige-woofers&Itemid=192


Greg

I bought a Adcom GFP-565 preamp and all is good except a scratchy pot. It is not bad and has cleared up some with use. However I can't let it slide! So I was wondering if anyone can suggest a replacement that would work for that pot. The ALPS model number is 051C-4170A07 50kX2. It is a 6 pin pot. I would be surprised if that was number was still able to be found so a quality replacement will also do.

Pico's Toxic Masculinity Chassis 4U x 500mm - Who is interested?

Just been speaking with Gianluca (Modushop) about doing a 4U 500mm Chassis.

For payment and ordering, follow link

Ricerca - 1HFTOXIC

For those who want to pay by PayPal or Credit Card simply choose "bank transfer" as payment method then send the money to webmaster@modu.it

Please make sure you choose the option "send money to friend or family member". The reason we are doing this is PayPal charges us a very high amount for, especially if the money comes from outside the EU.

Thanks for your understanding and your cooperation.

Back Panel

The IEC cutout on the back panel is compatible with either filtered or non-filtered Schurter power entry modules - Series 6765, FKI, FKH, FKID, FKHD should all fit.


If you're purchasing the Cardas Back Panel then you need to order these parts:

CARDAS PARTS SUPPLIED BY SONICRAFT

Binding posts

Cardas CCGR S Binding Post, Sonic Craft

RCAs SHORT VERSION

Cardas GRFA S RCA, Sonic Craft


RCAs LONG VERSION

Cardas GRFA L RCA, Sonic Craft

XLRs

Cardas CM F XLR Chassis XLR, Sonic Craft

Alternatively you could use Neutrik XLR jacks.


Shorting Pins For XLR's - OPTIONAL

Cardas CGSP, Sonic Craft

If you want to use other RCAs and Binding Posts then choose the back panel with pilot holes.
The XLR cutout is compatible with either Neutrik or Cardas this is common on both back panels

So far the list is:

Blk Dynamite x 2
Savu x 2
Mr Dewk x 2
Pico x 1 (maybe 2 if required to get to 25)
Gary S x 1 (maybe 3 if price is reduced further)
pwagner x 2 (maybe 3 if price is reduced further)
Hey Bill x 1 (maybe 2 if required to get to 25)
Super_BQ x 1 (maybe 2 if required to get to 25)
Mirio x 1 (maybe 2 if required to get to 25)
Ozorfis x 1 (maybe 2 if required to get to 25)
TungstenAudio x 1 (maybe 2 if required to get to 25)
ItsAllInMyHead x 1 (maybe 2 if required to get to 25)
Gnub x 1
Subbu k x 1
hifibluedevil x 1
BrianGasberg x 1
Gerald1951 x1
Cakyol x 1
vvs07 x 1
6L6 x 1
Theodosis O. x 1
Dennis Hui x 1
Kasey197 x 1
Sampsonite x 1
Argos x 1
wg45 x 1
dantwomey x 1
32y0 x 1
Kbergsson x 1
Analogdiy x 1
ggetzoff x 1

Well, I really don't use this amp so it's time to move it on to someone who will appreciate it more than I.

I rescued it from a music store going out of business. It was dead when I acquired it, so I pulled it apart and made some repairs to it, mostly bad solder joints and replaced all the fuses inside. The amplifier works, but it's going to need some assistance. First and foremost, the RCA inputs need to be replaced. The original ones use ceramic insulators which are cracked and no longer functioning well. The other issue is the left side meter does not work. If I jump the right meter to left it functions, so the meter itself is good, it looks like the board that drives the meter may need some help. Looks like a pretty simple circuit but I don't have time to play with it. One of the speaker terminals is missing its plastic nut, but still works.

You'll also notice the case is scuffed up and could use some help. Side panels are badly chipped but not dented, you'll also notice the right meter has a crack in the acrylic. I thought it was a scratch, but I was never able to polish it out.

This machine is 100% original. No modifications, no changes, no rebuild, it is bone stock. The meter switches on the front do work.

PM me if you need any more information I'll be happy to answer any questions. Shipping for this is probably gonna be about $100+ as it weighs 60 pounds.

I'm asking $800 O.B.O for it, substantially less than I can probably get for on eBay, but I'd rather have someone who could appreciate it get it.

WTB:

18M/4631T00​

https://www.scan-speak.dk/product/18m-4631t00/

I have a Alchemist Kraken power amplifier with what looks like a DC relay protection circuit.
There is no output on the binding post. If i mesure the speaker output before the DC circuit i get about 15 volts DC left and right.
There seems to be a repair don i the past (by factory?)

What will be the usual suspects, the PSU?

This is just a long shot and there is probably no satisfactory solution.

My Ditton 44’s are nearly 50 years old. I recapped them a couple of years ago and replaced the tweeters with Seas 19TFF1’s. (Thanks alan-1-b and others). I spent a lot of time fine tuning the voicing with ERS compensating resistors and they sound beautifully balanced; in fact better than original.

I have a spare set of mid drivers. I did have a set of woofers but they both failed after 6 months so I put the good originals back. (I always put the ones I buy in the speakers and keep the originals as spare).

Sooner or later though these old woofers will also fail but I don’t want to buy another set of used T1600s (or T2619s), so the question is: are there any modern 12 inch woofers which will work in 44’s without too much alteration to the crossovers? I can mess about with caps as I have some spare ones but don’t want the change the inductors as the cost would make this exercise pointless. The plan would be to buy one driver and test it out.

Some candidate drivers are listed below. I could only find three as the impedance of the T1600 is 4 ohms. Maybe there are others though.

What are the most critical values?

If Vas is critical then the volume of a 44 cab is about 60 L.

I realise that there may be some speculative replies but it would be really helpful if any of you have actually done this or can definitively rule out any / all of the drivers I listed.

Thanks Gordon

I was wondering if someone could help. I have a blue led in circuit. Running across it is 2.84 vdc but it doesnt light. When i take it out of circuit and test it with diode test it lights. Ive checked and it wired in correct way in circuit + and - correctly. I have a 100 ohm resistor before the led.

Hello dear forum users, my English knowledge is not good, so I use google translation. I need your help. I am looking for original transistors for the repair of my amplifier:
Sanken 2SA1295 + 2SC3264 + SK216 + SJ79
There are offers on the Internet, but these no longer seem to be originals, but fakes from China, bad replicas. Does anyone know of a commercial dealer who still has the originals on offer? Or do any of you still have some in your spare parts store?

Thank you very much

First off I am technically very ignorant so please bear with me. I just purchased an already built Korg Nutube B1 and have it paired with a First Watt F6 and my source is a dvd transport and solid state dac. I have a rapid sounding pop pop pop or click click click sound coming from the mid woofer on my two-way speakers (they are fairly inefficient speakers) when the Nutube is turned on. I have switched interconnects, switched to dvd transport only (eliminating dac) and I have taken the Nutube out of the circuit and the sound goes away.

I opened the preamp and there is no sign of burns or anything on the circuit board and all connections seem solid. Can I take this to an audio tech or is the circuit too esoteric and is there anything I can look for that would determine anything? Thanks for your help.

'Machang Music & Pictures' Seems to be a record-presser in Korea. We do have old scratchy films from the 1950s of how it was done at RCA and similar. This is a lot cleaner but also far smaller production.
On YouTube
Yes, "sound wrinkles" is not how we say it here, but is perfectly logical.

Hi, this is my first post. I just started to learn electronics repair from YouTube videos with no prior electronics background.
I am attempting to fix a Polk Woodburne Bluetooth speaker that would not power up due to a short circuit, as a learning project. With a dim bulb connected, I can power up multiple times without touching/changing anything, and get intermittent shorts. When it does not short, the speaker will work flawlessly until I either restart or put into standby and reawaken, and the intermittent shorts continue. In standby mode, which uses 5V power, I get no shorts. I have changed the amp power section capacitors in vain. Will try the power supply capacitors for 30V supply once I get the parts. I have also checked connections to speakers etc and all seem fine. Am I on the right track? Also, Google for schematics have not been successful, not that I would be able to properly understand anyway 😅. Thanks!

I have for sale one used toroid transfomers:

a) 60VA 1x230Vac, 2x12Vac (12-0-12), weight: 850g, price: 10 EUR + post costs + PP fee



b) 750VA, 1x230Vac, 1x18Vac, dimensions: 140x70 mm, weight: 5,2 kg, price: SOLD

Selling complete 94, 95, 96, 97 and 98 years as in various conditions as shown in the photos. Taking offers for shipping only. Selling All Years Together Only at this time. Please message me. Thanks.

I just picked up some Crystal 40 that the cross overs have blown caps,
can someone help with wiring back together, red black green yellow blue brown
Cheers
ng

Hello,

I have 2 pairs of vgs matched 2SK182ES that I bought from Pras a few years ago which I never used.
I would like to trade one pair of the two for a pair of vgs matched THF51S. You can choose the vgs you want from mine.

Thanks.

Best regards.

Hi all,
Been working on this receiver for a bit and have reached a blockage point. I'm hopeful for some insight on what's going on - thank you much in advance for your input!

This was a "not turning on" unit when I got it, that I tracked down to the MPX unit shorting the Vcc rail to ground (I could have fried some eggs on the regulator heatsink prior to fixing it). Upon recapping it (and the rest of the lythics - some were leaked), and tinkering a bit more with the connections to the board (such as reflowing the solder, cleaning up the grounds, etc.) it's now:
- working as far as preamp/amp stages go (which I adjusted and they're working very well);
- the tuning meter now deflects as I dial the tuning up and down (which wasn't happening before - neither AM, nor FM, as they were fed from the same clamped rail);

It seems the lingering issue is now still with the MPX module. I don't get audio out, and some voltage readings are enclosed (on top: stereo, bottom: mono, where different). Some obvious trouble seems to inflict Q401, Q402, Q403, though I don't have a good understanding of what's going on there.

I suspected Q401 has some issue (short?) between gate and source, and replaced the 2SK23 with a PN4393 selected for a Vgsoff of 1.17V and Idss of 8.45mA (which I feel is a suitable replacement, but welcome thoughts) but that returns returns the exact same values (and it seems to amplify the input signal to a decent waveform). I believe I also disconnected the input to the MPX and got the same elevated gate voltage, so the issue doesn't seem to be originating upstream. I am increasingly becoming weary that the coils there (MU401, T401) may be damaged. All transistors seem to pass the diode test out of circuit, though that's obviously not always positively relevant (so it very well could be that a certain transistor - such as Q402?... Q403? - is failed). But I just can't see how some failure of Q402/403 can trigger the Q401 gate issue, therefore my conundrum.

I am not sure the stereo bulb is conducting, but I assume R411 is there to prevent a burnt bulb from stopping stereo operation, so I didn't worry too much about it.

Any input much appreciated!

On the left we have Sweet Spot Gummi Worms
On the right we have Distinct High Performance Speaker Cables

The gummi worms weigh in at 400 grams and contain corn syrup, beef gelatin and citric acid, with 16 calories per worm.
Th cables are 14 gauge, 4 meters in length and have gold plated connectors. Spades on one end, banana on the other.

Which one wins? That depends on your criteria.
The gummi worms come it at $4.99 CAD
The cables are $3.49 CAD

Since they actually work, I'm heading back to the store and not for more worms.

Hello diy people!
I'm sure it's been discussed. I just can't find it. I have a Chinese board that calls for 32-0-32 vac with only three terminals. I want to use an transformer with 32v secondary and four wires. Can this be done? How is it done? Or, can anyone point me to the threads/posts about this? The Chinese transformer with 3 wires will cost an extra 50 bucks to ship. The Antek with 4 is free shipping.
Thank you for your help
Kevin

Do any of you know if Kondo (Audio Note Japan) uses a regulator on the heater supply for the Ongaku M77 preamp? Looking at pictures on the web, I see a TO-3 package... but it could be a slow start, a capacitance multiplier, a regulator, or something else. In my DIY, I identify products that appeal to my leanings and learn from them, but I haven't been able to crack this nut.
Thanks muchly.

I have an offset rv7 and RV8 at the back of a Rogers a75-s2 amplifier that needs to be adjusted. I don't know how many millivolts the resistance at both ends of its emitter e is. Please help me have a look. The manual of the machine is attached. Thank you,

Sorry if this has been discussed (I must have missed the meeting in that case), but what are the thoughts on adding a shoutbox for people to shoot the crap with while online?

I have 2 Adcom GFA-565 Monoblock Poweramps and while both turn on having power, they are not delivering any sound to connected speakers. The speakers work properly as well as the cables connecting them function. Also, there's no "pop" noise when turning the amps on from the speakers connected. There used to be this noise when switching on the amps, along with the sound being delivered to the speakers, but all of a sudden this has stopped. Any advice would be greatly appreciated.

Hello,

I'm looking for a monitor to use in video van.
Listeners are only at 1m from speakers.

Due to programs captured (live music), it will be nice to detect defects, but I understand that I'm far from normal listening conditions.

Auratone/advantone are used for proximity monitor, but is it the answer ?

thanks