Hello all
I am keen to build a 300B single ended vacuum kit - i have been looking at the Elkit 8900 with Lundal transformers.
i would appreciate advice re this kit or any other kit that would be worthy to build .
I have built a few valve amp kits now , whilst nit an expert - certainly competent and careful.

Hi all, and a Merry Christmas🎄🎄

I'm looking to replace the bridge rectifier on a Rotel 920ax amp. Currently it's a pbp206, which is no longer made, and as I understand it needs to be improved upon in this amp, as Rotel's have a habit of eating their rectifier.
What would be a suitable option that can be relied upon in the long term.
(Have attached the service manual)
Thank you all in advance 👍
Seasons best wishes to all 🎄🎄🎄

I built an ACA and was quite blown away, then did an F5.

The F5 isn't housed in a chassis yet, but wires are fairly well separated.
Its got maybe 15hrs on it. It seems to be missing something in the upper bass, the acoustic bass in Tears in Heaven by Clapton (live) has almost disappeared, its very faint.
The ACA presents the same song bewdifully!
Checked all phasing which was fine, yet the lower bass registers are also fine. I noticed the upper bass missing in quite a few other CD's but never really nailed exactly what was missing until I played Tears in Heaven.

F5 bias is set at 0.59vDC, DC offset 10~15mV.
I have P1 mounted, set mid range (30 turn pots) so set at 15 turns
Heatsinks are static at 39degC
Rails are +/- 22.8vDC

It's using the following;
Antek 5218
Monolithic 35A Rectifiers
16 gauge wire for DC power
Twisted CAT5 for inputs
16 gauge output wire
120,000uF Caps total (+ and -)

When I changed the ACA v1.8 out for the F5, I changed nothing else.. just the amps.

Similar threads missing under the last post.

A note / reminder that it must not appear in the location @AllenB reported, when it does become public (see: https://www.diyaudio.com/community/...-platform-feedback-wanted.380360/post-6883098).

The new feature that allows one to select text in a post and then be used as a quote. It works well and is very handy on desktop, but seems quirky on mobile.
I've gotten it to work only once. Every other time I've tried it takes me to the reply window, but the quote is not there. Is anyone else having this problem? Or am I doing it wrong?

What would be the best way to bypass Bax tone controls to get minimum switching noise and gain equal to tone controls centered?

This looks like a post by someone called Jason Steward

There have been several reports of no emails when new posts are made to previously subscribed-to (watched) threads.

We have all the data from the old forum, so these "watched threads" will be re-instated or restored if that's the issue.

😀 Hmmm... does someone know where cancer originates ?

I first thought its the bad fumes, smokes and alcohol... but i am starting to think otherwise... I blame DC 😀 PC's and alike, they are dead, like DC is dead, dead current brings death 😀

lol... it actually makes sense in someway.

Can someone argue with this?

Good evening gents,
Apologies, posted initially in the wrong place - will get the hang of things.
I'm laid up, no driving licence for 'dicky ticker' reasons' from October so I'm crawling up the walls. I have a weeks holiday at Christmas so I thought I'd get on with an audio project. I have a Rega record deck gathering dust on top of the wardrobe I thought I'd have a go at building an amp, not from discrete components I hasten to add. I've spotted the TDA7293 which seems ideal as a basis for this and studied the data sheet which has a couple of example circuits one of which is described as a TDA7293 block diagram. This diagram appears to relate to a PCB layout and is quite straightforward ie few components.. Is this a working circuit, I thought I'd knock it up over Christmas well at least the PCB. There are a couple of other circuits (modular and high efficiency) which are also on my radar although the component count of one is far higher. What are peoples thoughts on the circuit I should go for. Thanks in advance.

As it says on the tin...

--Christian

The jpgs on page 1 of the build guides do not seem to have transferred over.

Are signature lines now banned? Mine has gone and I no others can be seen.

Hi all,

I have been trying to understand all of IanCanada's offerings on Github.
GitHub - iancanada/DocumentDownload: Download documents of Ian's products

My idea is to use his board to build an RPi4 based Streamer/Player/DAC.

I would like the DAC to communicate to the RPi via I2S and have additional inputs for my laptop (USB), CD Player (SPDIF COax), Game Machine (TosLink), and mobile device (BT). I tried making a list of boards I would need but got lost.

I could not find any USB or BT input board nor how to connect the RPI to the DAC via I2S.

I do not need SPDIF outputs, I only need RCA and XLR, at this stage but if the space permits I don't see why I should leave them out.

I also don't want to get into the complications of a battery power supply because I don't know what it entails (Capacitor Conditioners, etc.).

I tried to make a list (see below) but would rather if a complete kit was available or maybe if someone help me determine which boards I would need.


BridgePi Adapter USB Interface to GPIO
DocumentDownload/BridgePiUsersManual.pdf at master * iancanada/DocumentDownload * GitHub

Isolator Pi II - I2S, DSD, DOP Isolator
DocumentDownload/IsolatorPi at master * iancanada/DocumentDownload * GitHub

FIFOPI Q3 ULTIMATE FIFO Reclocker
DocumentDownload/FifoPi at master * iancanada/DocumentDownload * GitHub

ShieldPi
DocumentDownload/Adapters/ShieldPi at master * iancanada/DocumentDownload * GitHub

Dual Mono ES9038Q2M DAC HAT
https://github.com/iancanada/DocumentDownload/tree/master/RPiDacHAT/ES9038Q2MDualMonoDacHAT

Transformer I/V (SE, Bal, Headphone)
https://github.com/iancanada/DocumentDownload/tree/master/RPiDacHAT/IVboards/LL1544aTranformerIV

I2S to HDMI Transmitter and Receiver
https://github.com/iancanada/DocumentDownload/tree/master/HDMIpi

Receiver Pi for TosLink and Coaxial Input
https://github.com/iancanada/DocumentDownload/tree/master/ReceiverPi
OR
SPDIF Inferface Board
https://github.com/iancanada/Docume...II series/SPDIFboard/SPDIF_InterfaceBoard.pdf

TransportPi for SPDIF, BNC and Optical output
https://github.com/iancanada/DocumentDownload/blob/master/TransportPi/TransportPiUsersManual.pdf

ESS controller + extension kit
https://github.com/iancanada/DocumentDownload/tree/master/ESScontroller
https://github.com/iancanada/DocumentDownload/tree/master/ESScontroller

Dual Linear Power supply
https://github.com/iancanada/DocumentDownload/tree/master/LinearPi

Thanks

I see some folks have links but I can t make mine work. Have links in the signatures been disabled for some reason?

Here's a chance to get a nice, low-mileage 577 that has been refurbished but hasn't been used to death. See full details and more pics on the eBay listing: https://www.ebay.com/itm/284580451537

$695 if bought directly from me. I have decades of good references available.

Hello everyone! I'm trying to design a compact home subwoofer using a pair of Hertz HS300 car subwoofers. I'm using them in a push-pull, 4th order bandpass configuration. They model pretty well on WinISD and BassBox in a 15lt(sealed chamber)+5lt(vented) bandpass enclosure tuned at 60Hz. I get a nice flat curve with low group delay with, even if I lose 9dB of efficiency it stays manageable (should be of around 82dB/W after being put in this bandpass box).
But doing so I encounter the usual issue with small displacement bass reflex subwoofers: the port is too long to fit in the box, even if I fold it. Reducing the diameter by a lot seems to help (I still need to fold the port) but because of the high Xmax and diameter of the subwoofers the vent air velocity is too high. This will lead to power compression issues and potentially port chuffing.
This issue is usually solved by replacing the traditional cylindrical or slotted port in favour of a more manageable passive radiator. However, I have no clue about how to deal with this particular situazion in which the bandpass enclosure and a PR are used in conjunction. How do I model the enclosure, and how do I find the correct mass to add to a PR of my choice?
I've been able to find some info on the internet about this type of use for the PR but no design tips.
Has anyone ever dealt with this problem?
Thanks
Piergiorgio

In this thread, I'll describe how to make some art for your walls.

This isn't audio related whatsoever, but I couldn't find any online forums for laser cutting which covered this, so here we are.

Hi,


I wasn't able to find out why an OPT should not be too big. Is there maybe no reason as long as ridiculous dimensions are not close yet?


Thank you!

Received this amp. Everything looks fine, until I inject a signal. Current draw is rising, output looks.. See picture.
The first picture is the amplitude at drain, without a signal. The other picture is the output with signal. Never had this issue.

Hello !

Maybe someone has a scheme of Sanyo M2528 LU - the model with IC Sanyo A1201.

Thanks

this on eBay and thought you might like it! Check it out now!
SIEMENS Gle 15000/1,5/6 Half Wave Mercury Vapor Rectifier Power supply ,lot 2

SIEMENS Gle 15000/1,5/6 Half Wave Mercury Vapor Rectifier Power supply ,lot 2 | eBay

Hi!

I have in stock excellent electron tubes
Reflektor 6N23P Silver Shield Single Wire Getter Post
All tubes NOS, the same data codes (November 1974).

Each tube was measured on The uTracer 3+

7 psc in stock, price 37 $/pc (for order all 7pcs - 10% off)
payment by PayPal

Best regards!

-------------------
Olexandr
Kharkiv, UKRAINE
skype: OAA-1974

Hi, I am selling a kit for an active 3-way speaker project, everything is new and unused:
The price would be € 140 + shipping

- 2 aluminum speaker plates with 6 connectors each plate
- cable 10m 6x2,5mm2 copper OFC cable
- 24 banana plugs, one is missing a trim (see photos)
- 4 connectors cable

I can not find any info on this amp at all anybody know its value....


Absolute monster working perfectly......

Everytime i google it it comes up with wrong one.....

Mine has got twin toroidals twin pairs of RIFA caps

12 2sa/2sc sanken...to3 per channel

Weighs the planet......

Contacted Bose even they sent me wrong schematic

Hey folks, I thought about buying some IC based output protection relays, similar IC's are used in some older commercial amplifier output protection. What do you think, are they good , have anyone had any experience with these?

https://www.ebay.com/itm/264663559721?hash=item3d9f2d6e29:g:cV0AAOSwIGhgQFrY

https://www.ebay.com/itm/3040842555...h4gQMExbZixuMb0Vly1at2/Ihw==|tkp:BFBMnM260blf

They seem very simple , basically all I need is DC protection in case of amplifier fault and overload or short circuit protection.

Dear All,

Does anybody have the schematic of the amp of the Sonus Faber Gravis B1 ? My subwoofer has an hum that I would like to eliminate (With input shorted) and the schematic would help.

Regards,

Davide

Best Buy has JBL GX1200 on sale for $29.

https://www.bestbuy.com/site/jbl-gx...07c4a0711ecb89912b6eb2019a40INT&skuId=6283643

Total noob here looking to build a reggae type sound system, would these work?
Any recommendations for box type?
Any advice or info would be greatly appreciated!

Thanks!

Hello

I have a Melos 333 phono stage which use 2 X 12AX7 and 2 X 6922/6DJ8.
I'm not sure where the 12AX7 and the 6922 go. As is, the 12AX7 are at the output stage and the 6922 in the front stage.
Like it is now, this phono stage doesn't have too much gain with big bass and no treble. I suspect the 12AX7 could go in the front end and the 6922 at output. I don't want to try that because I'm afraid to break something

Thanks

I have just recently bought a pair of Lumley Reference 120 Monobloc amps.
They are working fine but I have no manual or any other information about them.
Does anyone have a manual or schematic or indeed any information about the amps. They may need service at some point so anything would be useful and much appreciated.

I have been looking at doing a phono stage for quite a while now and having just "retired" I think I may get to start actually playing with it. I had been looking at passive v.s. active v.s. hybrid and was tending toward the later but I have become enamored of the idea of doing a battery powered version using either cordless tool or E-bike batteries. E-bike batteries are reasonably priced in the 36V models but horrendously expensive in the 60V models but tool batteries in 60V seem pretty affordable.

So in that vein I think that passive would be better for battery power as the supply voltage would have less effect on the response than it would using FB EQ. So I came up with this using a two stage FB amplifier front end followed by a single output stage with passive eq in between. Response follows the calculated values pretty closely but there is a 1dB per octave roll off starting at 200Hz. Being less than even a first order roll off I assume that it must be an artifact of the inverse RIAA model I picked up here rather than an actual behavior of the circuit. Can anyone confirm or destroy my reasoning here?

I'd like to build MTM center channel speaker with my existing 2x SB17NRX, cross low enough maybe around 350Hz to avoid issues with horizontal dispersion. so the option will be using 5" or 6" coaxial driver

candidates so far :

• sb16pfc25-4-coax
• celestion tfx0512
• faital pro 6hx150

in my short research, it seems using pro driver coaxial have benefit to provide more headroom instead of SB coaxial. i exclude using fullrange driver (i have 1 pair of alpair 10p unused) or maybe other 5" / 6" like fostex or lii audio which has lower headroom

any input will be appreciated, because i rarely find center speaker project with coaxial, majority using midrange + tweeter combination, where low height box is also my consideration. 20cm height is the maximum that i will use because it will be placed under TV

thanks

Hey Guys,

i've got 2 ScanSpeak 26W 4558 and am looking for the right enclosure.

The Setup:

2x Vifa 6/1 Coax as Tops.

A Sure/Wondom DSP + Amps + the possibility to measure some room dependencies with a superlux mic (for the finish 😉

Usage is Music (all kinds of).


Now the ScanSpeak Sub seems to be made for rather small enclosures. I could give each of the drivers up to 75L. I'm more a fan of CB Systems, but this maybe a more psychological thing. I'm aware of the possibility to use the passive radiator (like troels gravesen did 😉 but i have to opt out that idea, because of the aesthetics. The Subs should look like a scaled up version of the tops. Only one chassis on the front, and a size like: height 60 width 30 depth 40 (just that you get an idea).

Can you guys help me, finding some good solutions for two enclosures in between 50-80 litres, cb or if it is much better br.. ?


Thank you guys in advance. Any informations are appreciated!


Nickelle

For sale is a great pair of Mullard ECC33, NOS NIB tubes. I tested them, to be sure, on my AVO CT160 tube tester. They are in great condition, as are the boxes. Everything is original. 600€ pair.

And, for sale is, unfortunatelly, only 1pcs rare Philips Miniwatt EL37, NOS NIB. It has 1282 K3 code, which indicates early Mullard production. Tested aswel, 100% NOS. 300€ 1pcs.

Regards

The original CrystalFET.

The original worked, and sounded nice, but suffered from a couple of issues:

1. At MC gain, the circuit ran flat out, with no degeneration (feedback) on the source of the JFET amplifiers. The circuit gain was completely dependent on carefully matching the J113 devices, and finding two with enough gain was very, very hard.

2. The circuit has negative PSRR. It literally amplifiers the B+ signal on the output. (negative PSRR!). That meant the power supply had to do all the heavy lifting to reduce ripple and noise to vanishingly small levels.

At first, my followup was just going to remove the MC gain configuration and be MM only. On further consideration, however, it seemed sensible to adopt the feedback RIAA topology often seen on the old 12AX7 tube preamp designs, to at least some ripple rejection and make the whole thing a little less dependent on having matched devices.

A recent email I got inquiring after the CrystalFET prompted me to have another look at the problem. After a bit of messing around, this is the result.

[design idea, untested, for comment]

I regularly look at TG's page and came across a new build. Something caught my eye: Those speakers have awful surrounds! 😳 And I thought if they look awful to me, what about the WAF?
We read Purifi's description:

• Low Surround Radiation Distortion
o The surround contributes to sound output. Conventional surrounds produce distortion as they
deform. PURIFI’s Neutral Surround geometry avoids this mechanism without constraining motion.
This reduces harmonic distortion as well as intermodulation distortion.

http://www.troelsgravesen.dk/Purifi-6661.htmhttp://www.troelsgravesen.dk/Purifi-6661/PTT6.5W08-01A.pdf
I suppose a grate with a nice fabric could convince a wife, although in my case I have not yet built the ones I owe her for my DTQWTII ... 😉

Hey

All this is, is a simple quick fun speaker project that I want to do and ask a few questions about

what I want to do:

There are these silver Jaycar budget car speakers in the form of a 6x9, with there covers on they look quite industrial and
hardy, they are 4 ohms each and are 5 way coaxials and I want to buy 8 pairs, installing 8 per speaker resulting in an 8 ohm load which I want.

I dont want like some super duper high end speaker but want to turn them into a party music pumping machines, I can get 8 pairs for $320 AU here in Tasmania

I want bass only down to about 50 hz or lower and im prepared to make the enclosure 1.5 metres high and upto 50cms back and 30cm wide and it must be vented or slealed nothing else

I just want to ask what to watch out for? and any comments, because I haven't found a thing on line arrays for coaxial speakers

Anyone with a PCB for LM3886/LM3876/ LM4880 in INDIA..few each pls help
Thanks

Does anyone have problems with replying to posts and quoting them?
For most posts, if I hit "REPLY" button, the body of the message is blank.

Only in 1 in 10 cases, the previous post would be quoted in the web form.
It's been like this for a week or two...
It seems to depend on the content of the quoted post.

I'm using Firefox browser.
=================

I see now the anouncement made July 20th regarding this behavior.
While I do not agree with the idea, I understand the problem..

I've got a hefty power transformer sitting around, taken from a 5-channel x 100w receiver built around 2002.
Pioneer I believe, long trashed.
I've ran some tests on the transformer, and posted my findings in the photo here.
What I'm asking for is.... if adapting to use this for a 2ch stereo amp, custom build, what would be a suitable A/B BJT design, and useful VA rating of this hunk of iron?

Hi all,
I'm looking for a source for these right PCB mount pushbutton switches. Anything I find online is a straight through design, not this weird right angle orientation.

Looking for 2PDT and 3PDT

I have three Dayton Audio MTMC-1.0BK 1.0 cu. ft. MTM Curved Speaker Cabinets Gloss Black that i am wanting to sell.

These are awesome cabinets, I have two that I used for little 8" subs and I loved them, but I got these for another project that never went forward, You know how that goes :-/

They have never even been opened and these are not for sale any longer. I'd prefer to sell in my area, I'm in seattle. But willing to negotiate if there is real interest.

I'm hoping to get 100 per box, but i'd be willing to sell all three for 250

here ya go

I have successfully completed construction of my Tubelab Simple SE amp. No problems so far and, in general, it sounds fantastic except for the very high end. Using the amp with either 6.5 in or 12 in very efficient Audio Nirvana full range Supers, I get significant harshness/distortion at the high end of the frequency range -- sort of like ice picks to the ears especially at higher volume levels but also there even at modest volume levels. I am running EL34s at about 23 Watts dissipation in Triode mode and the output transformers are Edcor GXSE15-8-5. Would using cathode feedback (without UL) be likely to get rid of the high frequency harshness?

Thanks

Have a customer's 7500 on the bench now. Traced the blown fuse to modules one and five and have disconnected them to test the other three, which are working fine.

The problem is that after removing the screws that hold the PCB and heat sink and the RCA jack, the module is still captured by the two 5/16 nuts that connect it to the binding post, which is in a cramped space.

Normal socket is too short to get past the shaft. Deep socket is too long to fit in there when on a ratchet.

I managed to loosen the top nut with a 12" longnose pliers, but can't get my hand into that space to loosen and later assemble that connection.

Am wondering if anyone has a better solution or suggestion for a special tool that can do the job?

Hi all, if you have experience with this please see my post:
https://www.diyaudio.com/community/...or-house-wall-vibrations.380814/#post-6884656

I am not able to find explanations of Panasonic's date codes for their electrolytic capacitors that match what I am seeing on a recent batch of various caps.

It is not a simple YYWW like Nichicon uses. Have searched here and AudioKarma, and googled....

Does anybody know how to read their date code?

I have for sale LM3886 chipamp boards + psu boards.

15EUR

Payment by paypall+papall fee+ shipping.

I need assistance troubleshooting this Korean amplifier that runs on LM319 and two 74HC02. It's not producing low side drive,it powers up for like 1 second and I get a DC spike on the low side drive before the amp goes into protection.

How do you go about determining the cabinet volume for a seal enclosure. By this I mean, if I want the cabinet to net 35 hz, how do I determine the cabinet size?

I've been working my way through TC's BIB thread and was wondering if Hemp Acoustics was still together. None of the links to their website work and I've only found 2 sites selling their drivers, e-speakers and ebay.

Hi all,

I recently purchased a used Exposure 2010S2 integrated amplifier. Asking for your advice on something I noticed:

The amplifier makes a pop sound (through the speakers) when switching the power on.
However, it looks like there is a relay in it which clicks about 4 seconds after powering the amp on. I would suppose that is the speaker output protection relay, but
what puzzles me is that if I have a source (e.g. the cd player) already active and playing, I can hear music through the speakers
immediately after powering on the amp (no matter if the relay has "clicked" already or not yet).

I own another 2 amplifiers, an Exposure 2010 (a 2000-2001 model) and a Sony TA-FA3ES (a 1995 model).
Both of them have the relay thing which clicks about 4-5 seconds after pushing the power button on, but those would not
play any music before the relay clicks (even if the source is active already). As soon as the relay "click" is heard, only then music would be heard through the speakers.

Given the above, am I looking at a faulty 2010S2 relay or some other faulty component in it?

Hi there!

Has anyone ever built the Emory Cook/Gus Jose "Ultimate Amp" partly described in the attached? Is there any reason to build it now?

I have the rest of the article, the parts list and the schematic if anyone is interested.

Hi. I've not yet built my own speakers, but like the idea of trying it. I stumbled across Mark Audio after seeing a YouTube video about the Pearl Acoustics Sibelius speakers. They are ridiculously expensive for something with no crossover components and drivers at less than £100 a pair. If they are as good as the hype, I like the idea of building my own using the same or similar full range drivers. However, a kit would cost about £600 and the suppliers don't appear to have any demo facilities to listen before deciding if they are any better than my current Mordaunt Short MS908i Avants.

Is there anybody on here within striking distance of Cheshire that would be prepared to let me listen to anything similar that you have built? I'm thinking about either the Pluvia or Alpair 11 MS drivers in either Frugelhorn XL or the Pensil enclosures.

In the absence of any opportunity to listen, can anyone steer me in the right direction? I really like my current speakers but wonder if there is another level of performance out there in terms of retaining the base extension but improving the level of detail and precision of the soundstage?

According to the KJF website, Alpair drivers are superior to the Pluvia's and the mono suspension is a development, but the frequency response graph of the Alpair 11 MS appears to have a heavy dip half way up, well within the audible range. Is that a problem?

If it helps, my amp is a Cambridge Audio Azure and the room I listen in is about the size of a single garage.

Many thanks in advance for any help or advice.

Hi,

After building a few 2-way speakers (which I'm pretty content with) I decided to try to take the leap and try to build a 3-way.
And I'm looking for some feedback on what I believe should be all right.
So after days of trying to find the right drivers that play a little nice together I came up with a system that I believe should work.
My current system will have:

• Woofer: Dayton Audio RS225-4 (8")
• Mid: Dayton Audio RS125-4 (4")
• Tweeter: Dayton Audio TD20F-4

The crossover looks like this:
(Please ignore the shorted / open parts as I was still toying around with values 🙂 )



The FRD Like this:



Impedance:



The only thing I'm not sure about is how to interpet phase in VituixCAD and I'm kinda hoping I've done it right 🙂




The drivers itself will be inside a vented enclosure in which I'll make some compartements (the woofer will be in it's own compartement where the mid and tweeter will be stuck together)

So what do you guys think? Is this all right? Or did I miss something / mess something up?

Any feedback will be greatly appericiated!

The effects of Karlson's reflective system were mentioned in reports from its demonstation at the fall 1954 Hi Fi show K12 introduction and illustrated in the early Karlson "12" brochure as "Aural Optics". (Bose and others referenced the patent)

A "generally cubical"cabinet ("Fig.1") was used in the patent and simplified in construction with its backwave passing over a gap between its slanted baffle and cabinet top. That gap may have been 2 inches high.

Anyhow, in such a structure I think the tight end of the aperture is setting system resonance and that Karlson probably would have not tuned this cubical "K12" higher than 70Hz.

Can it be guesstimated in hornresp and assuming "so", what model would suit?


(wonder how is "sounded"? - it might be a fun bujld)

I have 2 brand new Sjostrom Audio QSXM3 Extreme Phono Preamp pcb boards available. These are bare boards and do not include any other parts or components. $75 each plus shipping. PayPal ok with added transaction fee.

PM me if interested.

For sale
LSK 170 A
LSJ 74 A

Europe

When I return to a thread that I've read before, it goes to the beginning of the thread
instead of where I left off. I couldn't find any setting to change that.

Hi,

I am measuering a bipolar lythic of a loudspeaker in shunt position after a resistor from a bass low pass section...

On a 100uF cap I see there are few difference between the moment where the cap was pulled out of the speaker filter that was in use the day before, and then 24 hours after. The capacitance value droped from around 0,300 uF on each channel after a night rest.

After a 24h rest, the capacitance meter gives after few seconds a 0,1 uF more then few seconds later 0,1 uF more yet ! I assume it is because of the DC charging from the capacitance hand meter. However the 0,300 uF are not recovered in the few seconds when I repeat the measurement.
What is please the acurate value I should keep for the filter calculation please ?

Despite a loudspeaker filter is seing AC, impulse currents, is it safe to say the damping resistor in the filter is acting as a polarising part for few undred nano cause the bipolar cap is after ? Or it is just due to the natural loading and unloading behavior of a cap whatever it ks jn a filtef cir uit and being bipolar in seie with the signal return, i.e. negative pole ?

So what do the filter see ? The cold rested measurement of the ca pvalue or the few hundred nano Farads more of the capwhen the loudspeakers are playing back music ?

I also assume than my cheap tool is more handy for classic non polar cap measurement than bipolar caps ! But the value of the two caps with the two ways of measuring go from 103.00 to 103.3 and 103.4.... and in the filter development setup the few hundred are important enough to be heard. Ok yhe ears will find what is needed qnd I can add for instance a decoupling of what is needed with precise MKP caps, but the questions are more about knowledge curiosity.

Thanks for your testimonials. Cheers.

My douglas@ email went quiet at some point in January. Apparently my mailbox on the server was full. All reset now, apologies for those that weren't able to get ahold of me!

Hey everyone, first of all, i'm sorry for regurgitating this topic.
I'm trying to fix the single ended input on a TPA3116D module i bought to work with my CSR8675.
I have seen other threads, posts and videos on this topic [1][2][3] but none of them were helpful here, because i don't quite understand the single-ended input conversion done on this board. (I'm a total beginner on this stuff)

So my naive approach here was to just remove C2, C3, C1, R4 and R5 and then add some bodge wires to the pads that go directly to pin 4,5,10,11 respectively on the TPA.
However, this didn't entirely work:

• The potentiometer still has some function that i honestly don't quite understand (ideally, i'd just want the TPA to run at about 70% volume and control the gain from the CSR otherwise, because this board also has the incorrect potentiometer installed like almost every other implementation...)
• The left output (pin 10,11) does not work at all and is just extremely noisy when i hook it up to the CSR
• The right output works somewhat (see next point)
• The amp seems to be in a strange state now where it won't power up "warm" (when i switch off my bench supply and switch it back on, it sometimes doesn't turn on, sometimes draws a unexpectedly high amount of current, etc., waiting a bit (presumably for caps to drain) fixes this. (I unknowingly removed some discharge resistor, didn't i? ....)

So basically i'm really confused because i've never done anything like this and could use some help from someone who has seen all these crappy single-ended input boards and can help me out. 😕



1: https://www.diyaudio.com/community/threads/tpa3116-csr8635-idle-noise.310628/page-2
2: Login to view embedded media 3: https://www.simplemedianetworks.com/mods/differential-tpa3116

This old girl will not power up, but is drawing 0Amps and then 1.5A when I apply rem. There is no drive signal to the PS devices nor at the transformer. A TC4027 and TC4011 ICs are on the PS board. I have not really investigated much, still determining repairability.

Is there a schematic for this or similar oldie?

This will be the story of how this sketch.....



.....inspired by this great piece of work (the Linkwitz Orion).....



.....also inspired by some of my own experiments.....





... turned into this ! 🙂

So I'm in the process of refurbishing that 60s made Vidaire Catalina tube amp.

Strangely, there are 3 different types of capacitors there, all carrying the same rating of 0.1uf/400v

Can anyone explain why they used different types of caps while they are all of the same ratings? Is there a specific reason for using different types?

Around each of the 6AN8 tube there is one huge yellow 0.1uf/400v cap, along with two smaller yellow 0.1uf/400v caps.

What new caps exactly should I use at each position? Is the bigger paper cap polarized? it does have a black ring on one side...

The "death cap" is also a 0.1uf/400v, also of a different type. I already removed it but wondering why they are all different?

Also... there's one 3VDC/50uf polarized cap around those 6AN8. A 3v cap on a tube? does it make sense or am I missing anything... can it just be replaced with a 47uf/16v electrolyte?

Thanks!

https://www.fulcrum-acoustic.com/wp-content/uploads/2021/12/Prod-Spec-DF463-v1.pdf
Looks like dual AXI 2050's to me 😛.........?

Needing more money to acoustically improve my listening room, I´m letting go of my Kiseki Blacheart NS. 11 months old, and has played exactly 30 LP´s (kept track).
I´m the only owner, and it was bought directly from the danish distributer. I only have receipt as PDF on e-mail, which can be forwarded to buyer.

Note: This cartridge is quite particular on azimut and VTA settings, so unless you are able to adjust these properly, you might want to look elsewhere.

There´s a used Blackheart for sale on AudioMarkt/Germany for 4000 Euro´s.
I´m letting mine go for 3000 Euro incl. tracked shipping in EU.
Taking PayPal (+ 4%, or the family and friends option). Preferably EU only.

Just moved into a new house, and can´t find my camera, and my cell cam won´t take close ups/macro, so photo is as good as it get´s of the actual unit.

All relevant info is available on WWW. Particularly take note of channel separation and channel balance, which are among the very best 🙂

For a long I am using the Edifier K550 headphone just as my computer audio listening device.
I am now testing this headphone on my latest tube headphone amplifier design to
experience the amplifiers performance with low impedance headphones ranging from 30 Ohms (the K550)
(because it is the only one I have at this moment), to 70 Ohms (the Sennheiser HD25),
(the amplifier can also handle a high impedance headphone like my Sennheiser HD650).
To my very surprise with listening tests, that cheap K550 sounds unexpectedly good both at low and at high frequencies.
And yes, it is personal taste of course. So I decided to purchase another one of that K550 but to my
great disappointment I cannot purchase this type over here in the Netherlands or any other European country.
Or did I overlook something?

hi,
i'm having an issue with the 6.5 speakers, they get a lot of water on them because of poor VW door design and this actually gets a bit in the car when raining.
i've found a special sort of cloth membrane (some poliurethane from a clothing factory) which is 100% waterproof and want to wrap my 6.5 speaker in it, but this material doesn't let air go thru also.
does anyone know or have any idea how the speaker will perform? (material will not make any noise/vibrate it's very soft and has a side which is like a cloth)
i'm interested in what way will the sound be affected? will get worse? will get better mid-bass? the air behind the cone will push the cone back and obtain unwanted sound reprodution?
any idea?
thanks

Dear All,

Please have a critique of my schematic and PCB layout for the Bob Cordell Super Gainclone "TM".

I think the C1A and C2A should go to the main ground. At present I've got it to "Quiet Ground".

Any input is most welcome.

Cheers.

I use a pair of Sony CD players, model CDP-CX350. One of them has a very faint LED display. Can someone tell me if this is something that can be repaired? Sony no longer supply specific Sony parts for this model so simply trying swapping a new display panel is not possible. I was wondering if this is a common problem that can only be rectified by display panel replacement, cleaning or resoldering connections, or replacing a chip or some other component that controls the operation of the display. I don't have the knowledge of how these things work but I do have the skills required to identify and replace an IC or some rogue resistor if someone can point me in the right direction.
Thanks in advance.

i am using 2 4ohm dynaudio 17w75xl drivers in series for a 2 way speaker.
david morison helped me before i tried using winisd. and came up with 10L for closed box volume for 17w75xl
it's a flat curve . id like a little steeper slope so tried smaller volume to boost upper bass frequencies

i am using iso-barik setting on winisd to model the output.
so when using one 4ohm 17w75xl driver in 6 L box I get the same plot
as when using two 4ohm 17w75xl drivers in 3L box. i understand 4ohm driver is more efficient than two 4 ohm paired into an 8ohm.

but shouldn't the box for 2 driver be twice the size of a box for one driver?

so shouldnt two 17w75xl connected in series require a 12L box as opposed to a 3L box

whats the error?

i attached images of winisd results
green graph is a graph of 8ohm polk mw6503 driver i am looking to replace with 2 17w75xl drivers
blue graph is one 17w75xl 4ohm in 7L box(if i put 6L volume it overlaps with 3L graph )
yellow is two 17w75xl 4ohm in series in a 3L box

My car's speakers are currently powered by a four-channel amplifier. I plan to buy a 12-inch subwoofer as well as an amplifier to power it. I've run a 4 gauge wire to the trunk for my existing amp. I'll get a distribution block and connect it using 4 gauge wire, as well as 8 gauge wire from the block to each amp. My question is: how do I determine the fuse size to use? I already have a 60amp fuse for the current amp, and I'm not sure what size fuse I'll need to replace it with. Do I replace my 60 amp fuse with a 120 amp fuse or leave my 60 amp fuse because the new amp will almost certainly require a 60 amp fuse? I believe I only require a single 60 amp fuse, but I'd like to double-check before purchasing anything. Thanks.

I just stumbled across the 6N17B pencil tube and it looks intriguing as a phono preamp input tube as it has fairly high mu and reasonable input capacitance. I suspect that it might also be fairly free of microphonics.

I suppose that these types of tubes might be inconvenient having no base but I suppose perf board could be used. Pencils could be a very interesting subspecies to play with.

I've been doing some driver 'research' in google images and came across a couple of unusual drivers I never expected to see.

I thought it would make a fun thread to collect images and details of unusual or weird drivers.

I'll start with ScanSpeak coaxial that appears to have polystyrene slapped on the front!

https://s3t.it/weirdness/scanspeak-13m-coaxial/



Next we have a grotesque version o the famous ScanSpeak mid-bass.

https://diyspeakers.eu/product/scan-speak-11m-4631g05-gold/



Then I'll add this one because it is such an unusual suspension arrangement, at least it is these days.

I am using the Aurora dsp and am ready to move start creating my own sigma studio design and customize the platform.
what I cannot figure out is how to set the akm adc and dac to 96k sampling rate.

anyone know?