Hi, I have a pair of AR-410s that I am going to rebuild. I would be grateful for answers to some questions and any suggestions towards best performance. The amp is form 1953. Is that before the riaa curve? Will the 12au7 work well as a phono stage? Can I use just a SUT? Would I have to change the circuit to use 6v6 tubes instead of 6f6? Thank you!

So here we are with my never to be complete list of things and projects I never will build.

Let’s start with the obvious:


…

I have heard from most sellers at those days, that solder connection wasn't a good idea due additional wires consisting of aluminum.

Therefore the question: what is the best way to connect this cable to a plug or terminal ?

Concerning the HA-20 are to read the same question, but without helpful replies:
https://forum.psaudio.com/t/golden-conductors-in-a-vintage-japanese-cable/26577
here a solder connection was created with a 4mm plug
http://www.diybuy.net/thread-1373461-1-1.html

Additional I want to know, what has been tried to achieve with the internal structure of the cable (go to attached images) ?
If I see this correctly, one strand is a relatively thick copper cable, which is wrapped with another cable, which in turn has the same basic structure (i.e. also a copper cable, but a thinner one, which is also wrapped with a very thin wire)

Maybe there are descriptions and datasheet published (maybe also a patent).
Thank you very much for upload such papers and an advice for a solution for connect terminals.

P.S.: Images of HB-55:
https://www.diyaudio.com/community/...5-single-wire-cable-what-other-option.347897/
more URLs:
https://www.ebay.com/itm/403259337836
https://www.htforum.nl/yabbse/index.php?topic=115216.0
https://www.analogueseduction.net/terminated/townshend-dct-isolda-speaker-cables.html
https://www.hifido.co.jp/sold/21-30...0&M=0&LNG=E&OD=0&O=100&L=50&SD1=0&SD2=0&SD3=0
http://www.audiopigiau.lt/produktas/isoda-electric-ha-20/
https://www.hifido.co.jp/sold/10-52914-75585-00.html?LNG=E
https://www.htforum.nl/yabbse/index.php?topic=115216.0

Perhaps the slightly misleading title will catch some attention😀
I say "misleading" because there is no ratings to be found on this particular tube. Let's start from the beginning: A couple of decades ago when I was new to this hobby, I bought a large stash of NOS 12A6 metal cased tubes from a surplus dealer for very little money. I still have at least a couple of dozens of them left plus a some well suited mains transformers with 12V heater windings and a pair of OPTs that would be a perfect match for a 12A6 parallel push pull project.

The thing that bothers me a little bit is that those OPT's have 15% CFB windings which will put some voltage swing on the cathodes, 40Vpp or so att full power.
Most tubes can take +-100V or so between heater and cathode but the 12A6 datasheet states:
"In circuits where the cathode is not directly connected to the heater, the potential difference between heater and cathode should be kept as low as possible".

There´s not much practical information about the 12A6 online, this is a tube that suffers from seriously low Audiophile Swag, but some of the old Heathkit A7 schematics shows 12A6s being operated with grounded heater windings while the cathodes are at 20V or so.

Pair of 8" Silver Flute woofers for sale in perfect condition. Never soldered, or over driven.
Asking $60.00 plus shipping. Ship to lower 48 states only. Thanks for looking.

As it says in the TITLE.

It can be completed boards, it can be fully built amp.

Much appreciated.

I have tried to understand my XO, and asked about it before. I first thought it was a Butterworth or an LR or adjusted to some measurements, since it didn't pass with the values that are in the filter. And I know that you cannot just calculate the exact value, as the impedance is not constant and other things. But since the tweeter is 8.2 µF capacitor and a 0.2 (0.22) mH coil, so it is actually very close to a 2. order Chebychev. If you just use a calculator, a LR generally gives a relatively small capacitor and a relatively large coil, a BUT gives a slightly larger capacitor and a slightly smaller coil and a Chebychev gives a large capacitor and small coil. Just like my HighPass. As I have read it, Chebychev has a Qualityfactor (Q) of 1, and BUT of 0.7 and LR of 0.5. According to The Crossover Design Cookbook by Mark Lawrence, a Q value of 1 is too large and it will sound terrible with a lot of ringing. There are probably many errors with my speakers, but ringing is not an issue, it's a rather polished sound mayby to polished.

What I have read should beeing the advantage of Chebychev should be that it rolls off faster. Then I get confused again. Rolls off faster, that's a 2. order filter, so all the filters probably roll off equally fast, i.e. 12 dB per octave ore have I misunderstod. Ore does it means that the rooloff is more "sharp" when it starts to roll off.
By the way, it also surprises me that by playing a little with different XO frequencies in a calculator and an impedance of 6 ohms, the XO frequence is just over 3,000 Hz. The Bass is cross by a 2.2 mH coil, and then a coil a resistor and a capacitor in parallel with the Bass. So the low-pass filter is probably just a 1st order filter with an LRC filter. 1st order filter with a 2.2 mH coil gives a XO approx. 500 Hz. That gives now sence.

This is my first time doing anything with diy audio, so i'm confused on what I actually need.
So far I have picked these components

This is the amplifier TDA7498E 2.1
Full range drivers Eminence Alpha 4-8 4" 90-12,000hz
Tweeters Peerless by Tymphany DX25TG59-04

With the tweeters and drivers, do I need a cross over with them? Do I build the cross over or would a premade board work?
Any other tips would be great also.

curious.............

after seeing "Hello, I bought a pair of SDS-160F25PR01-08 and two pairs of Peerless tweeters, TX25BG60-04 and BC25TG15-04 to choose for MLTL, it is possible that you can share me your MLTL design please?" (audiomovil)

then

"Greets!

FYI/FWIW, you got me curious to try HR's wizard, so did a max flat default L*0.349 offset MLTL (61.5" tall/56.36 L/35 Hz Fb) based on a a fairly common 38" seated ear height to the woofer center, though of course all can be adjusted to suit if driver offset is one of these: (L) ~ 0 (top), 0.217, 0.349, 0.424; vent: (L) ~0.651, 0.714, 0.848, 0 (bottom)" (GM)


Tall box though................................

Is this what they a C-core? Thanks

Link to transformer

Has anyone listed speaker models that can be tri wired?

Here are a couple to start you off: (no esoteric or custom models, in other words those that are within a £ 1,000 budget S/H)
1. Epos M16
2. Epos M22
3. Epos ES22
4 Linn Keilidh (active tri-amp)
5. Linn Kaber
6. Linn Ninka (active tri-amp)
?

Is Panasonic Su series capacitor good for audio applications?

Hi everyone!
This is my first post here on the forum.
I have a GAS Thaedra that needs new capacitors on the regulator board 321B.
What´s the best capacitor to replace the old ones with?
The ones sitting there is 4 1000 µF 35 V and 4 1000 µF 50 V.

I've just acquired some Eclipse TD510s in good cosmetic condition but non-working. No sound whatsoever (tried 2 amps) and no ohm reading on the terminals. Seems like the voice coils have burnt out which isn't difficult to do considering the low power handling (20 watts).

The drivers are bespoke 120mm full range, and due to the unusual enclosure design / suspension they need to be a perfect fit. I doubt a drop in replacement would work.



Eclipse don't offer any support at all with regards to spares / repair so my only potential avenue is 3rd party. Can anyone recommend a repairer (ideally UK based)?

Cheers

Dawson

Seems Mouser has given up on hole through parts. But have good luck with Digikey. I was ordering lastnite and was takin back to discover. So I will use Digikey now. I hope their shipping is faster?

Hi all,

Who else besides Wima makes film / foil capacitors of 1uF and larger? FKPs are sold out at all my usual suppliers. I'd like to avoid the likes of Mundorf, Riken etc. and stick with an industrial manufacturer.

Kemet (Evox/Rifa) do the PFR510 series, but only up to 22nF, PHE448 up to 3.3nF, A72 no stock above 220nF, and R73 also no stock anywhere.

I'd be grateful for any ideas 🙂

Edit: I almost forgot CD "Orange Drop" 716P, but also no stock.

Hi, I have a pair of Gale Gold Monitor speakers, however one tweeter is blown.

I am looking for a replacement unit, they appear to be bonded into a plastic housing (painted silver), so i am looking for the entire assembly.

thanks,

I have a Signature amp and schematics but they fail to provide the Test Point information and values at these points also the bias settings,can anyone help?The unit currently powers up for approx 20 seconds then powers down(no speakers connected) and returns to Standby.

Apparently, the former employees of ERSE have started a new company and will get the coils/bobbins from the now ERSE-parent company in China.

https://uscoils.us/

I look for this to become another solid supplier of coils/caps, and hopefully return SuperQ coils to the market.

I am considering purchasing Ian Canadas most recent Fifo reclocker and dual mono DACs to build an integrated streamer / DAC. I am interested in anyone who has experience using these boards and can opine on SQ. And I would love feedback on the two PSUs he offers as well - the LinearPi ultra low noise linear PSU and the PurePi Batter PSU - both with ultra caps.

-Chris

Too new to this field to deserve a "newbie" sobriquet but here I am... an apprentice pre-newbie

In the attachment you will find the associated schematic from German's brand Teladi Elektroakustik GmbH.
The power amp unit is the same in the model MV05
Is this a good approach or are there better solutions ?
Thank you for an advice

Been building an amp around 2 of these for what feels like forever:

UPC1342V 2SC5200 2SA1943 220W Mono Power Amplifier Board Kit HiFi Class A Amp | eBay

(not from ebay, but its the same kit from China)

All was going well (after a few smoke/fire 'learning' moments), had it working for a good couple of weeks while I waited for a few last parts, more heatsinks etc.

As i came to test it prior to my absolutely final re-assembly, the left amp board gives out a very load buzzing, accompanied by a hefty pop when power is cut. The right side amp seems to be fine and plays audio as before.

I've eye-balled the PCB and it looks fine, tried the other power from the transformer and switched inputs and outputs around to the point I am confident the issue is the PCB.

2 things that could have caused an issue. there's a chance a shred of metal from heatsink drilling got in there somewhere, although I cleaned it with compressed air before I powered it up with that in mind.

the other ****-up i made...in the case, i have a PCB for the volume pot about 5mm above one if the caps on the amp, and this 'slipped' and was probably touching the top of the cap, I dunno if electrical contact was made, or if damage could have been caused if there was.

Could this have caused permanent damage? or anything I can do to check it before I order another amp PCB (my 4th!)

Looking back on my years in hifi, from sales back in the 80s to rookie circuit repair and "upgrades" today, and all the listening and enjoyment I've gotten out of it throughout my life, I have an appreciation for products from certain designers. I wanted to name my three favorites, and I encourage everyone who reads this to name theirs. And discuss it. Thats part of why we're here.

Here's my top three, no particular order:

- Nelson Pass (and not just because he might see this). His time is limited and valuable yet he still answers questions and participates in DIY camps. He designed the simplest amp I've ever owned, the one that got me into the study of electronics, the Adcom GFA-555. Its my stand-by, my go-to, the one amp I can depend on because there's so little that can go wrong with it yet so much that goes right. Everyone else needs twice the parts to do half the job that Nelson does.

- Jim Strickland (RIP). He designed the Acoustat TNP (Trans Nova Preamp), which morphed into the IRIS preamp after he was brought into Rockford Fosgate's Hafler unit. The IRIS was the second preamp I owned after my Hafler DH110, and it served me well for a decade. A cap refresh turned it into something amazing. I could sell every other preamp I have (I lost count and keep finding them around the house) and as long as I had my modded IRIS to stick in front of whatever amp I kept for last, I'd be fine with that. I didn't find out until too late that Jim lived not too far from where I lived at the time. Opportunity missed.

- Stan Warren (MIA). The mad scientist of Oregon. His PS Audio and Superphon designs were noteworthy, but he had a second career of doing mods on other peoples' designs. I've owned a Warren-mod amp and the changes were the craziest stuff - pronounced "impossible" by a couple of people in the business who looked at it - but they worked. The sound had an unearthly character: crisp like solid state yet sweet like a fine tube amp. If you've never heard an amp Stan upgraded, try not to. You're probably never going to forget it and you'll judge everything else you hear against that one amp. I wouldn't miss any chance to learn from Nelson or Jim Fosgate or John Curl, but Stan Warren is the one guy I'd really like to study with. I have so many questions for him. He and I have mutual friends and I've been trying to find him for years, but that may never happen. (Stan, if you see this, send me a PM).

And because I'm certain no one here including myself is able to keep the list down to three, here's my honorable mentions:

Erno Borbeley (he has had his hands in a lot more than just the Hafler 200, but since almost every other David Hafler amp started right there with the exception of the SE series - I think - Erno's had quite the contribution to my hifi experience)
Jim Fosgate (too many to list but I would start with his original mobile audio designs which turned the industry on its ear, and the man is still going strong in his 80s with Black Ice Audio)
James Bongiorno (RIP, again many designs but the early Sumo is exquisite)
Bob Carver (I was fascinated by the tales of his amp challenge back in the 80s, and years later I had a chance to work on some of his products and own a few. Interesting designs with cheap parts, similar to Hafler but in some cases with far poorer-quality PCBs. Yet where the Hafler sound can be flat to a fault, Carver stuff is just more fun for me to listen to. Both respond well to parts upgrades. Bob's a really interesting guy, kind of a blend of Nelson and Bongiorno, the engineer and the artist. I wish I could afford his new tube stuff.)
Paul McGowan (he knows the business side as well as the design side, and he's a fun person to listen to. His explanations of some basics like transistors and power supplies have really helped my studies)
John Iverson (MIA, quite literally! Electron Kinetics, Electro Research, plus the Robertson Audio Ten Forty and Ten Sixty that may have been lifted directly from his work)

Finally, a shoutout to the unknown designer who came up with the NAD 2150 and 2200 amplifiers and their 1155 preamp. Top flight work, all around.

Hi all,
I need an advice for adding an active subwoofer to a stereo setup based on preamp+power amp and a pair of fullranges in BIB (setup n. 2 in signature) in order to fill the very low end, possibly without using active crossover for high pass. What is the best way?
Thanks in advance,
Vinz

Hi!
I have a problem with the Audison amplifier. I don't know why it doesn't come out of "safe" mode. I was wondering if the problem was with the power supply or the amplifier. I pulled out 4 rectifier diodes, but the problem persists, it seems to me that it is somewhere in the power section, but I can't find anything. There was a bit of cold solder which I tweaked, but the problem persists.

All measurements were made at a voltage of 13.50V relative to the "-BATT" (power ground).
I think the SG2525AP is broken, but i'm not sure.

SG2525AP

P1 - 2,21V
P2 - 2,66V
P3 - 0.00V
P4 - 0.38V
P5 - 2.02V
P6 - 3.84V
P7 - 1.96V
P8 - 0.30V

P9 - 6.00V
P10 - 3.98V
P11 - 0.00V
P12 - GND
P13 - 13,48V
P14 - 0,00V
P15 - 13,44V
P16 - 5,18V

BA10393 (dual comparator)

P1 - 12,56V
P2 - 2,26V
P3 - 11,31V
P4 - GND
P5 - 12,57V
P6 - 11,31V
P7 - 13,39V
P8 - 13,44V


The schematic screenshots that I added in the attachment are from the LRX 1.400 model (follow the zippyshare link for the complete schematic), which is a monoblock.
The protect section is the same.
Unfortunately, I did not find the LRX 4.300.

https://www30.zippyshare.com/v/5PGBR9Mm/file.html

Hi all,

Very interested in the Overnight Sensation design to use as nearfield monitors in my home DJ studio. I like the idea of the extra bump in output and extension the second driver in the MTM version would provide vs the basic MT, but given the way I would be using/placing the speakers I would greatly benefit from the tweeter at the top at the top of the cabinet with both of the mids below, like you would see on a floorstanding speaker. This would make it far easier to get the tweeters better aligned at my ear level given the short distances from the listening position (3-5 feet). Could there be any serious detriment to the response if I reconfigured the drivers in this way, though?

Because there are still many out there who think that it is almost impossible to build PWM amps using post-filter NFB takeoff - I made an attempt to calculate such an NFB loop. I went to the extreme and took a fourth order output filter (f3=50 kHz, Bessel). I publish it here even at the risk that someone will go and patent it. 😉

Just some remarks:

1.) I actually know that real life is real life and simulations are just simulations so I don't want any discussions on that subject.

2.) I know the advantages of self oscillating topologies. I used a carrier-based one because "I come from there" and also because there are many ICs and other solutions for carrier-based class-d around that still use the same boring old NFB topologies.

3.) The same transfer functions can be achieved with alternative circuits. I just used the second topology that crossed my mind. These may even perform better in real life than the one here because they would need less op-amps or put less stress on them. I think I don't have to mention that careful choice of op-amps would be critical in real life.
Because my version of P-SPICE is very restricted I used the voltage-controlled voltage-source model insted of op-amps. It is of course possible to use multiple nested feedback loops instead of the single-loop topology presented here.

4.) I by myself would most probably not build a class-d amp with fourth-order filter because all the component tolerances are much tighter than they would be with a 2nd order filter. Carrier suppresion of 2nd order filters is also sufficient in most cases.

If you have a look a the schematic you can see a classic PID around E1. This one is responsible to build a first-order behaviour, together with one pole-pair of the output filter (ca 70 kHz, Q=0.52).
The second pole-pair (approx 80 kHz, Q=0.8) is dealt with by the circuit around E37 and E10 with the transfer function s^2T^2 + sT/Q + 1.

Because the transfer-function of the feedback-branch is a PD the closed-loop frequency response is a first-order lowpass. I tried with different loads between 2 Ohms and 1 k (nominal = 6 Ohms) and the response deviation was around 0.3 dB at 20 kHz. Deviations were a little "adventurous" above 30 kHz, but this wouldn't be that much of a problem with "normal" loads and clever choice of Zobel values.

On the open-loop gain diagram one can see that the whole loop has a first-order behaviour (well, almost) and the unity-gain point is 200 kHz approx. Phase-marging is 80 degrees approx !

The simulation I would trust the least is the transient analysis (i.e. the THD part to be exact). One can see the output signal when driven 20 dB below full output. There is not very much of the carrier left over ! The FFT shows that all harmonics of the "payload" are suppressed by more than 80 dB.

While the topology as such would theoretically work it is still not complete and it would show a "dangerous" restriction, depending on the input signal. I will elaborate on this later. Everybody is invited though to find that one out by himself in the meantime !

Regards

Charles

So i accidentally bought the R2R-XY3-V8 board that uses XY-2 R2R dac modules and since it is on its way to me why not make an NOS dac out of it.
The board that i found. It shifts the data. Do i really need this or any usb to I2S can do NOS? Or i'm completely wrong about it.

Hi,

I found some of this boards in my house... 2010! And I will try to build it. But I have some questions.

http://jhaible.com/legacy/subtle_chorus/jh_subtle_chorus.html

You can build the vintage version with HA1457W ( obsolet ) or the modern with standard TL072. And with or without power transistors.

What is the difference of building the version with or without power transistors?

In the BOM of the main board say ( vintage )

HA1457W:

Vintage OpAmp in SIL package. If you don't find these, you
can build a modern version with TL072's (and without power
transitors) - there's a different BOM for this version.
Or, if you want to use the power transitor output stage
without HA1457W's, try other Dual OpAmps in the DIL8
package. I'm sure there are some that will work. (TL072's will
not work in that configuration - there's oscillation on
capacitive load!)

The question is. Worth build the modern version with power transistors? in this case, what IC I can try to avoid this oscillation?

Thanks.

P.D.: I've read somewhere that there are a Burr Brown IC that is very similar to the HA1457W. OPA604 maybe?

Draws about 1.5 amps, unloaded. No lights come on whatsoever.

TL494C chip DC voltages
1. 0
2. .56
3. .07
4. 0
5. .01
6. 0
7. 0
8. 1.9
9. .05
10. .05
11. 1.9
12. 1.2
13. .575
14. .575
15. .575
16. 0

I pulled the data sheet on the 494 and was expected 5 V on pin 14 and 12 V on pin 12. This amp was built in December 2013 according to the tag. The only PG diagram I can find online is a different unit altogether from 1995.

Thanks for any help or suggestions.

This speakers were a projet built one year ago for a friend.
It is an improved speaker Based on Troels Gravesen SBA941 upgrading midrange to Satori MW16TX-8
Drivers are Satori TW29BN-B-8 Beryllium + Satori MW16TX-8 TexTreme + Satori WO24P-8 woofer
Original SBAcoustics Grilles.

Cabinets were built with 19mm MDF with internal bracing and acoustic absorbers to avoid resonances.
Is was veneered with Zebrano Veneer and barnished with 7 layers of polyurethane varnish with polishing between each layer.

Filters were buil with jantzen Audio Z-Superior + ribbon copper coils at tweeter, Z-standard + air core + iron core with discs at midrange and iron core with discs + cross caps at woofer section.
All internal wires are Janzen Audiuo Silver.

Crossover points are 550 and 1850 Hz LR2
Attached you will see 1/24 octave smoother curves and 1/6 octave as well.
Impedance is 8 ohm and sens around 88dB. An easy load for any amp.

My friend is asking 2200€ + PP fees + shipping.
They are in absolutely SuperB condition, and he is sellind due to his WAF... who doesn´t like them on the sitting rooom.

I haven't found anything specifically addressing this on here, so apologies if I've missed something.

I'm intrigued by the BBC technique of mounting their bass-mid drive units on the back of the baffle, rather than on the front as is more usual. It may be a hangover from the 1960s when most speakers had removable baffles and a seal on the front of the drive unit. However even more recent iterations - such as Harbeth and Stirling Broadcast - continue the tradition.

Can anyone point to an advantage in doing it this way? Smoother transition between drive unit and baffle?

for sale brand new in box the Nelson Pass O2 N channel Vfet output kit. It will come with pair of NOS 2SK60. Also included in the kit is Mark Johnson‘s Ship Of Theseus power supply filter board. These are now available since I have built the P channel version. Asking $295 Plus shipping to the lower 48 state please.

All14 "Linear Audio" volumes plus "Baxandall & Self on Audio Power" for sale. I would like to get $100 for the lot. US shipping only via Media Mail.

Watt pusher used a white noise CD from Denon and free Audacity software recorder to analyze frequency response of a speaker: https://www.diyaudio.com/community/threads/vintage-acoustic-807-pa-loudspeaker-cabinet-rehab.380210/
I can't get Audacity for linux lubuntu20.04 to see any input. I have measured the 3.5 mm phone plug going in the blue jack of PC, 0.92 to 0.95 vac tip to shaft. I have the speaker playing white noise MP3 via media player on the PC. The PV8 mixer sees about -6 db on LED display. The headphone output of PV8 hears the white noise on left channel.
With free download PC software "pulse audio volume meter" I can see sound in the middle of the bars when the white noise is playing on the speaker. That means I think it is going in the PC and being digitized.
With audacity recorded track I am seeing only -1 db spikes every 0.3 to 0.8 seconds. That is with ALSA set to line 0 , then line 1, then mike 0, then mike 1. I'm recording monaural. Audacity mixer board display sees nothing. ???
BTW I started with "roomequalizerwizard" for linux. After downloading, double clicking didn't start it. When I tried to read the .sh file (a script) the text editor said it contained non-text codes and wouldn't display. I've looked at other .sh files when I had a lubuntu problem, they were all text files. So much for REW linux version IMHO.

I wanted to try an Isobaric with a removable cylindrical container and made a "one piece motor" by gluing 3/4" x 3/4" rings together. The setup was way better than previous attempts.
1. cut the inter circle first
2. use the waste/cutout to center the piece to the sliding table (2nd pic top).
3. glue together with spring clamps, etc.

Box size, 1 cubic foot with deductions for venting and cylindrical container calculated in.

The woofer is a Buyout from PE, very low cost but well made.
Simulated in WinIsd, clearly shows a response down to 25hz.

299-114 subwoofer speaker features a deep profile, long fiber, high-pulp cone finished beautifully in a protective coating that also dampens resonances. The 1-1/2" diameter 4-layer voice coil's 5/8" winding length maintains plenty of copper in the magnetic gap, ensuring plenty of high-impact, low-distortion output. A vented pole piece reduces performance-robbing power compression, and the magnet structure's extended back plate prevents "bottoming out" the long voice coil. Great subwoofer speaker for any design or application, particularly multimedia systems, small home theater setups, and multi-driver configurations.

Specifications:
*Power handling: 80 watts RMS/160 watts max
*VCdia: 1-1/2"
*Le: 1.61 mH
*Impedance: 4 ohms
*Re: 3.25 ohms
*Frequency response: 35-2,000 Hz
*Fs: 38 Hz *SPL: 83.5 dB 1W/1m
*Vas: 0.55 cu. ft. *Qms: 6.74
*Qes: 0.64 *Qts: 0.59
*Xmax: 4.5 mm
*OD: 6-1/2"

A few more finish steps to go, will be testing soon though.

I want to put 2 Jordan Eikona drivers in series in a mltl enclosure. I want to work out the port length but don't know what to enter for the Thiele Small parameters. Can anyone help please?

Hi. I'm in to building valve amplifiers and hope to get started with speakers.

Edit
Edit

I built an F5 turbo v2 for turntable and CDs.

Now I need a new receiver to update the new codecs. But figured I'd build my own amplifiers for the speakers and buy a processor. So I don't have to pay for the amplifier part in these integrated receivers which never really got loud enough.

But I can't afford to buy and build another F5 turbo especially considering I need five of them.

So I got interested in class D amps given relatively low cost to build. Then I came across the chip amp for the same reason.

Reading the forums I couldn't work out which would be more appropriate for my needs.

The only source will be digital from streaming services or the PS5 via the TV.

Anyone have any thoughts on the matter and can point me in the right direction? The LM3886 seemed popular...

Thanks.

since I went a different route with my amps ect I’m going to build an entirely new setup in my suv .

Wondering if MDF is still the go to wood for building a sub enclosure?

I’ve heard people using Baltic birch ect .

Maybe it was just my ears playing tricks on me that day but I’ve heard a couple enclosures built from birch and didn’t really care for the sound . It just sounded different then an MDF enclosure .

Hi,

what is a reasonable safety factor for the previous stage’s current vs the required current to ensure the needed slew rate for the following stage? 2x, 5x, 10x?

Thank you in advance,
Roberto

I have a older Rod Coleman reg kit I plan to use. Reading the instructions, it refers to a FET for Q1. My kit has a BJT...no FETs. Can someone please tell me what FET is used for Q1?

The Pass B1 buffered passive preamp has been around for quite some time, and has been built many times around the globe.
What is missing is a balanced version of.
And even more difficult is to make it fully symmetrical (eletrically), i.e. truely dual mono.
Just search around in Google for balanced passive preamp, and you will realise.

We mentioned earlier that the guys in Hong Kong want to have a summer amp that does not dissipate too much.
There is already an example of a balanced LM4780 for that :
https://www.diyaudio.com/community/...approach-the-build-thread.208880/post-6271567
But he also wants a matching preamp to go with it.
Since the LM4780 itself has already enough gain, a passive preamp with discrete output buffers, a sort of a balanced DCB1, would be ideal.

So here is the result, even though not quite 100% finished.





Enjoy,
Patrick

.

Hi friends! I come back with another rockford fosgate T10001bd, they tell me that they hit the speaker cables and it started to generate smoke. When checking it I found this damaged ground track, I did a general check and nothing else marked me wrong and when I turn it on the current consumption is high and the output fets make noise. I disassembled them to check them and I found no damage to the output fets and transistors mpsa56 and 06, I measured signals in the ic drivers u202 and u204, but u204 is always sending pulses, but 202 is not, when placing audio both send pulses. It is normal? and I see that the ic of u200 (lm6172) and u203 (tl072) are different greetings and I appreciate your support

Hi Everyone.
I have an amp that is 4x200w, and I am wanting to make it 100v for some distributed speakers on two of the channels.
The speakers all have transformers in them and are tapped at various wattages throughout each line on these two channels.

My questions come with regards to installing a transformer between the 8ohm Amp and the 100v line.
Will a transformer from an old speaker work? I have a transformer from an old speaker that had many taps/windings, one of which is 200w, the speaker it was installed in had an 8ohm driver. Would this work on one of the lines? Actual load on that line is likely to be around 150w at maximum, which it is likely to never run at. Would this work? I assume you would just adjust the volume of the amp channel to affect the whole line on that channel without causing any issues with the transformer?

If not, what type of transformer should I be putting in here? Any links to actual products would help a heap also.

Cheers,

I am from the Analog test and measurement equipment era , though I do have two Digital multimeters.
I am intending to buy a Computer , and want an operating system in it which will accept software for test and measurement of audio equipment.
I realise that many audio engineers use Apple/Mac systems though I prefer not that system unless there is no other comprehensive option.
I don’t much like Windows either , thus I am asking here ,
will the Linux operating system accept the various test and measurement software ?
or do the Manufacturers of test and measurement software only design and manufacture for Windows and Apple/Mac operating systems ?

Yes , you are correct , I am really not knowledgeable about computer systems ,
thus any information will be appreciated ,
or a direction to a Thread in this Forum , or to anywhere , where the above has been comprehensively explained.

It seems there are a lot of people, besides me of course, who have been wanting a good quality PCB for XBOSOZ. Well I have been pointed to several thread and tried to glean as much as I could. This is a completely no area for me, and my first pass at a Pass design. 🙂

First of all thank to all those who have paved the way. They did the real work here, this is very small thing compared to what those people have done.

So thanks to these people in Particular:

Nelson Pass, of course.
Metalman, Terry Aben whose circuit I followed.

But I am sure there are others who deserve credit, and to those I apologize for not knowing who you are.

Anyway they say a picture is worth a thousand words, so here are 2000 words worth.

First the Schematic:

Never used except for a 1 1/2” shorter lead that was trimmed off in anticipation of an amp build. Usually bought at $110 or so, but I can sell it for $75. Shipping from southern Ontario.

I dug out one of my old amps and remembered why I put it away in the first place:

I need the DIN power/control cord.
I think this is the part #:

Amp: Kenwood KAC-8020
Part # E30-1433-08

It's an 8-pin round connector (din), it is what runs up to the head unit (the input)
If I remember correctly, it also has the remote wire on it.

Any idea where I can get one? I found parts web sites, but most of them say 'discontinued'.

I could probably make my own cable, but I don't have the pin-out information either.

I hate to keep it moth-balled because I don't have the DIN cord.

Thanks,

H.


Here's a picture of the amp and the DIN connector:

I purchased an assembled 6AU6 6AQ5 SE Amp from China. It worked as assembled but was not correct. The PCB was not correct. I had to cut traces, add correct capacitors/resistors for the voltages and rewire correctly the power supply CRC filters. I have questions about the feedback connections circled in red in the attached picture. I have not seen this before having feedback connected to Pin 2 the suppressor of 6AU6. And I have not seen the R2 240k resistor feedback connected to the suppressor before, but to Pin 5 the plate. Are these connections correct or is this an error too? Or if correct how does this affect the circuit? >>>I have corrected schematic to show 5Y3GT and the added 10uf 400V Capacitor. ALSO Attaching Original Schematic<<<

I am thinking to have muses volume into b1k pre amp.
I found muses volume PCB.
https://nw-electric.way-nifty.com/blog/muses72323vol.html
https://nw-electric.way-nifty.com/blog/files/muses72323vol_sch_20210131.pdf
I only use for simple volume control without opamp.
Is this worth to build against Meldano's kit
or anything comment or tips?

Intrigued by how well my cheap 'n cheerful ESP P-06 build worked out, I've been playing around with an even simpler RIAA phono preamp made with an opamp > passive EQ > opamp. The PSU is repurposed from an earlier Hagerman Bugle build (+/-15VDC, using 7815/7915 ICs).

I believe I have a circuit that 'sounds good'. Now I'm playing around with the output capacitor and pulldown/load resistor.

I've looked around at other similar projects, and have found a lot of variation in values chosen for the output DC blocking cap (Cout) and output pulldown/load resistor (Rload). Many traditional 1980s-style designs use a large value capacitor with lower value resistor. For instance, I found one Graham Slee design which uses 10uF for Cout and 47k for Rload. Rod Elliott shows a few example designs that use Cout = 22uF and Rload = 22k ohms. But then the Muffsy and an ELENCO design use Cout = 1uF and Rload = 100k, while the RJM VSPS uses 2.2uF and 100k ohms. On the other hand, the TNT Solidphono goes to the other extreme and uses Cout = 0.33uF and Rload = 330k ohms, like early 1960s tube circuits would have used.

I'm left with the impression that the choice of values is less important than the resulting time constant. Is that correct?

One thing to take into consideration is the load impedance presented by the device to be driven by the phono preamp output.

- If that's going to be a preamp or amp with a 10k ohm volume control, then a 1uF output cap will result in an F3low of 16Hz, which would introduce a noticeable rolloff of low bass. (Perhaps that's desirable, though, as a rough 'n ready rumble filter?)

- Looking at the other extreme, if Cout = 22uF and Rload = 22k, and that feeds a 10k volume control, even though the resulting load (22k//10k) will be only 6875 ohms the F3low will be down at 1Hz. The Graham Slee values of 10uF and 47k results in F3low of only 0.34Hz, but if the load is a 10k volume control, F3low for that would go up to 1.9Hz. Perhaps that was the design goal there?

Let's say I'm not sure what my RIAA preamp will be driving. It could drive a class D amp with a 10k ohm volume pot on its input, or it could drive my living room stereo with an autoformer volume control (AV) which maintains a very high impedance load. Should I try to find a compromise solution that works OK with both? Or should I optimize for one extreme and assume it will be OK for the other?

I did have 1.5uF and 100k and that was working fine into the living room hi-fi w/ AVC. Into a 10k ohm load the F3low would go way up to 16Hz, but it's not a problem into the AVC.

Now I'm trying a 6.8uF 100V (big) film cap with 56k, which is predicted to have F3low of only 0.4Hz into a light load.
Should I change the Rload to 22k, so the F3low is about 1Hz? Would that conform better to best practices?

What are the pros and cons of bigger vs smaller value C and bigger vs smaller value R in this part of the circuit?

I understand that smaller value capacitors have advantages of lower inductance, lower ESR, etc.
Also, the smaller value of R allows the output cap to charge/discharge more quickly, reducing turn on/off thumps.

PS - Forgot to mention... I've read that a lower value of capacitance (e.g. 1uF) for the output DC blocking cap will have a higher reactance at low frequencies, so can make the circuit more susceptible to picking up hum from its interconnect cabling. Is that independent of the value of Rload? If that's true, and a higher value capacitor (e.g., 10uF) will help reject hum pickup, then perhaps that's an important issue for a standalone phono preamp as opposed to one that's built into a full-function preamp or integrated amp?

Are there other issues of importance?

Hello friends

Looking for a pair Scan Speak tweeters D2608/91300 in good conditions

Thanks
and regards

Josoeff

Various used and NOS/NIB valves for sale.
1) Two Sylvania 6S4A's matched in emission - 22.8mA/22.8mA one is yellow print, the other white. £20
2) Electro Harmonix tests good - 24mA. £10
3) Standard tests ok 21mA - £7
All tested at Va 250v, Vg1 -8v, Ik 24mA = on spec.
4) 11 Mullard PL504's NIB, not tested as I haven't a base. £7 each
5) Various used ECC88's, tested good to ok, pics shows various brands inc Brimar, Mullard etc. £4 each
6) A pair of ITT CV391's (807's in a different package) test good. £10 each
7) Pair of ITT CV428's ( 807's etc). £10 each.
8) Four 813 top caps, ceramic, new. £8 the lot.

Postage to UK mainland estimated @ £3,all valves will be well packed, happy to knock a few £'s off for multiple valves etc.

TFL, Andy.

I am researching EL34 PP amplifiers in the hopes of building one in the near future. Google throws up about 873 billion different designs though and I just want to make sure I'm not building an unproven (or even dangerously out of spec) design with brand new and very expensive components. My main amp is currently a Maggie 9303 EL84PP modified to Dave Gillespie's design and I am very fond of the sound. I need something that will fill a larger room though and I happen to already have a matched quad of EL34s. I think my preferred setup would be a dual monoblock in separate chassis from each other. Other than that I really don't care so long as it's a respected design and not overly complicated. Anybody want to point me toward something?

Hi All,

Just bump into these Chinese semiconductor website

http://www.xlsemi.net/products_AB_audio.html

Definitely have the numbers familiar?

Hi,

have some ALPS RK27x adapter pcbs left for sale.



Pot and connector strip not included, this is just the PCB.

Cost: 2€ each pcb

Shipping in a padded envelope (not tracked or insured):

• germany (without islands) : 2,50€
• world wide (without UK, sorry guys to much paperwork for the customs): 4,50€

After I unfortunately killed my Soekris dac due to an accidental short circuit, I am looking for a replacement as I got used to its sound. Could also be the latest rev.7 1021 board, as it's architecture s similar to the OEM board.

Hi all,
Some time ago I built a small battery powered sine wave signal gen to pair with my handheld oscilloscope for basic signal tracing. It's this one https://www.valvewizard.co.uk/siggen.html and seems to work well. But then I thought it would be nice to have a square wave output too so I added this one https://sound-au.com/articles/sqr-f14.gif from https://sound-au.com/articles/squarewave.htm in particular the sine to square converter scheme. This way I could have common frequency control for both waveforms but independent output level controls. The problem: The sine wave output is 0,7V rms and apparently this is not enough. You can see that the square is not symmetrical. When I feed it with another sine gen that does 2,6V rms things get a lot better however it seems it needs just a little more than this to be perfect. My conclusion is that it has to do with the Schmitt trigger input threshold but I wasn't able to understand the datasheet on this. So, the question is if there is anything I could adjust to make it work with 0,7V rms.

PS. The delayed rising time is intentional according to Rod Elliott's teaching. Also, the square out as is works to trace ringing, frequency response etc. It is also very good to tell if the DUT is inverting. 🙂 But it does not look nice...

Clearing out some stuff that I have no use for from a recent bulk-buy of parts and projects. Prefer shipping within EU, but world-wide shipping is of course possible.

**************
- Sjostrøm Audio SSR-03 no-compromise regulator PCBs with pre-mounted AD825 opamps.
On sale from Sjostrom for around 50 EUR, asking 30 EUR each. 5 Pcs. available.
https://sjostromaudio.com/pages/ind...ssr03-sjoestroem-super-regulator-power-supply


- Sjostrøm Audio DCT-02 DC-trap PCBs for buzzing toroids. Asking 10 EUR each, 2 pcs. available.
https://sjostromaudio.com/pages/index.php/hifi-projects/109-dct02-the-dc-trap-high-end-style

- Sjostrøm Audio SST-03 softstart PCB. Asking 15 EUR, 1 pc. available.
https://sjostromaudio.com/pages/ind...146-sst03-softstart-for-toroidal-transformers


- Original cViller F5 amplifier and PSU PCBs. Asking 15 EUR per set, 2 sets available.


- F1 amplifier and PSU PCBs. Unknown origin but looks fine, and in sealed shrink-wrap. Asking 15 EUR per set, 2 sets available.


- Aleph 5 clone PCBs from KK audio. Looks like an older version, unfortunately no PSU available. Asking 15 EUR for the pair.


- Original BrianGT Aleph-PCBs (can be used for Aleph 3 or Aleph Mini IIRC). Asking 12 EUR per pair, two pairs available.


- Original BrianGT/Chipamp snubberized LM3886 Gainclone PCBs (sorry, I have no spare LM3886s!). Asking 15 EUR for a set of two amp and two PSU-boards, 2 sets available.


- Zen V4 clone PCBs from jimsaudio, unopened. Asking 12 EUR for the pair.


- Jung/Didden Superreg-PCBs from the diyaudio-store. [SOLD]

Hey
Quick question does anybody know how similar they sound ?
I haven't heard r2905 970000
But i do like revelator and illuminator tweeters sound.
Price difference is rather small but r2905 97000 is very simple swap out tweeter.
R3004 660000 i must re-route front panel.
I have listened sonus faber amati furutura speakers and there is 2905 tweeter but i don't know wich one i suspect 930000 or 950000 becouse detail is little bit missing ?
I have own(ed) d3004/602000, r3004/602010, r2904/700005

Amplifier:
Musical Fidelity P270

Problem:
Lightning struck near my apartment at night.
The next day when I tried to turn on my device, smoke started pouring out.

What is broken:
This is an image from the web and the problem area is circled. This is where the capacitor and resistor are located. The value of the capacitor can be seen and no problem, but the resistor is so burnt that the value cannot be read. There are two resistances. One on each side. This connects the amplifier ground to the mains ground.


Situation:
My cousin is a good electronics mechanic.
Since the device is very old and out of warranty, and I don't have the money to send it abroad to an authorized service center (I live in Serbia), I let him fix it.
Since everything is burned, you can't tell which parts are involved, he needs an electronic circuit diagram.
I couldn't find an electronic circuit diagram on the internet.
I was looking for an electronic schematic of this device from the manufacturer. They forwarded my email to the authorized service. Of course they told me to bring it to them. There was no talk of an electronic circuit diagram.

Possible solutions:

• One of you has an electronic circuit diagram (or a link);
• one of you has the same amp, (take some photos of the problematic part).

Many many thanks

(Google Translate...) 🤐

Hi everyone,

After quite a few years not building any speakers anymore it started to itch again recently. With DSPs getting more affordable I wanted to try building some active speakers. I own a Sonos Connect so my idea was to connect 2 MiniDSP 2x4HD with a Toslink Optical splitter to the Connect. In that way I’d try to create some sort of high end Sonos speaker 🙂 So I started drawing something in Fusion 360.

For the look and feel of the speaker I took some inspiration from an existing German brand of speakers. I like the slightly angled baffle look and I wanted something that could cover the full range so it needed to be large enough to fit a decent subwoofer. My living room furniture is made of white oak and I have a black leather sofa, so this made up the choice of materials for the outside. Baffle with waveguide milled out of solid oak and panels with leather polstering.



Choice of drivers:
I personally like the sound of soft dome tweeters. I also wanted a good controlled directivity so I decided to integrate a waveguide. I went for the Scanspeak D2604/833000 after seeing the test results here. I intend to cross over at around 3 Khz
For high mid I chose Wavecor WF152CU14. I liked the low distortion of the driver and the look of the phase plug 🙂. If it helps in directivity we will see later. It should handle the range down to 500 Hz. For low mid I designed in 2 x Wavecor WF152BD03 in separate closed chambers of around 3.5 liter. They should handle down to around 125Hz.



For the low end I was looking what I could do with a volume of around 40 to 50l behind the drivers and came across this which I could integrate. So a 26W/4558T00 close to the floor on the one side and a passive radiator 26W/0-00-00 higher up on the other side to make it fit in the narrow housing. With the MiniDSP I will have the flexibility to adjust the response to the room a bit.



The setup is made of separate sections, which are screwed together with threaded inserts, so it is easy to take apart and tweak. Most of the walls are double MDF with some damping in between.



The amplifier is made of 4 UCD400OEM modules together with a SMPS1200 and is mounted with heatsinks underneath in the base of the speaker. I created a PCB with a simple gain stage to connect the amplifier modules and to fit some connectors for the drivers. Cooling air can enter from the bottom and exit on the side through venting holes which are covered by the cloth hiding the subwoofer.
I’m still looking to find a way to connect the baffle without the visible screws. I might try to do it with supermagnets. If anyone has other ideas how to do this, please let me know.
Next is starting to build something. I might do some youtube videos on progress if people are interested.

Hi.... as title suggests. Any experience out there?

I've used bypass caps on Mundorf HC series before, but wondered if there was any advantage to doing this on M-lytic AG series?

Not sure what the physical differences are between HC and AG caps and how a bypass cap might influence.

Thanks

I am currently working on a two-way ported passive design to act as my surrounds. This is my third design project and fourth build project (I built a predesigned Micro-Marty sub).

My first design and build was a fairly large two way build for my main L/R with Dayton RS-225-8 woofers and RST28A tweeters designed for a college project. I designed them with the help of a super friendly redditor. All design work was based on factory data and diffraction/enclosure simulations. It turned out good for my expectations.

My second build was a MTM center speaker using the same tweeter as before, but two RS150-4 woofers. Same thing, all just theoretical/simulation data used to design.

This go around I am using the RS150-8 and RST28A, but am trying to improve my process by taking and using my own measurements.

For FRD measurements I have a Dayton EMM-6 and Scarlett 2i2, I built a turntable/spinorama style stand to allow for off-axis measurements while keeping my drivers at the center of rotation. For ZMA I am just using a make shift DATs with resistors and my 2i2. I follow this guide here.

So far I have learned a decent amount and made quiet a few improvements that I will then propagate to my previous builds.

1. During initial impedance measurements I had a weird peak/dip in my woofer's impedance. Found it to be a cabinet resonance. Gluing a brace/strip of MDF between my two side walls fixed that. I am sure that is an issue for my 8in mains that can be fixed.

2. I found during initial farfield measurements of my tweeter that I had some pretty nasty peaks and dips from about 2-6 kHz. I found out part of my issue was having a surface mounted instead of flush mounted tweeter. I fixed that, and my results got better but still some improvement left on the table. I at the same time went ahead and flush mounted the tweeter on all my previous builds.

3. In a continued effort to fix my tweeter dip, I rounded my edges with a 1/2in radius roundover bit. I will eventually roundover the edges on all my other builds too. The result I got from this was slight improvement in my 2.5-4 kHz dip, but not much. It did also decrease the hard fall off I had above 10 kHz by a significant amount.

Here is an album that shows some of my measurements throughout my process and what the actual speakers look like.

So now I am trying to figure out what else I can do or should be looking for before taking a final spin measurement and starting crossover design.

I still have a significant dip between 2.5-4 kHz. I believe the biggest culprit here is having a symmetrical/centered tweeter. I know the obvious answer is make my tweeter off center, but that also sets me back a lot because it means cutting off my baffle, cutting a new one, and then repeating the counter sink and round over process. I was suggested at looking into a waveguide if I don't want to rebuild the baffle entirely, but I haven't found any that would fit on my 7.5in wide baffle that also has the proper mounting for the RST28A. I will likely look into the SEOS-8 for when I go to revise my mains build, as it will fit on those.

There are a couple of things I know now that it is slightly too late for this go around, unless I want to back track a lot, that I will use going forward. Making my tweeter off center and getting my tweeter as close to my woofer as possible.

So my questions now are:

1. Is there anything I can do to help mitigate my dip that is almost certainly (VituixCAD diffraction simulator agrees) due to my centered tweeter, without cutting off and rebuilding my entire baffle? I have been suggested 3d print a waveguide, but that is a whole can of worms I am not sure I want to spend the time learning about, plus I have heard wave guides have their own trade offs. As well, I was told I could put some F-13 felt around the tweeter, but then I have to find a way to make that aesthetically pleasing.

2. I made my tweeter flush, could I expect any benefit of making my woofer flush as well?

3. How do I properly handle merging my near field and far field woofer measurements seeing as I have a port? The previously listed VituixCAD guide suggests taking SPL nearfield measurements from the woofer and the port, but I am not sure how to handle merging both of those with the farfield.

4. I have largely just been looking at my SPL and ZMA results for things to improve. Are there other factors I should investigate before carrying on?

I am selling a pair of Bianco 15" woofer for open baffle use. I just bought them from TLHP ( France) and open the box to look at one of them.
I realized that the OB I was about to try is too big for my room and low WAF. They are new and didn't think I need to post pictures as they've never been used.

Asking $275 shipped to USCON.

Like a lot of people on this forum I want a quality measurement microphone but can't really justify a full professional set up.
B&K (or clone) external polarisation capsule + proprietary preamp body + external power source is the laboratory reference option but is expensive, inflexible and inconvenient (not easily portable).
But the cheap Electret Condenser Mics tend to distort and lack stability over time.
So what are the options in the middle?
1. Use a B&K style capsule connected to a 48V Phantom powered body to provide the 200 V polarisation and the preamp (actually an impedance buffer)
Gefell and Josephson make such bodies but they are expensive and would be somewhat difficult to DIY.
[Edit] So it's a nice option if you have the money to buy ready-made "top of the line" hardware.

2. Use a B&K style pre-polarised capsule connected to a P48 V body that only has to do impedance buffer duties.
These capsules are fairly common and almost a commodity item, made by B&K, DPA, G.R.A.S., Gefell, Norsonic, ACO Pacific and PCB Piezotronics, so there's a reasonable chance to find one at a reasonable price.
This is a simpler system and naturally there are more commercial options.
ACO Pacific, and PCB Piezotronics do "measurement mics" and DPA market their's as an omnidirectional, flat response "studio mic".
MicW is the studio mic division of BSWA (like DPA to B&K) and claims to have a decent measurement mic.
These are less expensive but still not cheap ~$500 for the body.
I have had a look at some of the JFET buffer circuits from Borbely and Bob Cordell and it seems it shouldn't be too expensive.
[Edit] So a DIY kit could be almost "top of the line" and more than adequate but far cheaper.

Since option 2 is my choice - has anybody seen a DIY "preamp" body kit or have ideas for the circuit?
I am tempted to try a fully complementary circuit but a kit makes sense, if only to simplify the mechanics, so I don't have to cut odd sized capsule threads and find Teflon insulators and similar obscure parts.

David

Hello, i'm starting a new speaker project using Markaudio drivers. First a small desktop cabinet using the chn-50 in a bass reflex enclosure, for this i need an amplifier that can deliver 7 watts in 4 ohms, it can be class A or AB.

The second project will be a bit bigger, using the CHR-70 in a pensil style enclosure or some other form of floor standing cabinet, for this i need an amplifier that can deliver 20 watts in 8 ohms, i think for this one a class AB amp will be ideal, maybe something around the lm3886 chip.

What would you guys recommend for both this projects? any help will be greatly appreciated, thanks in advance, cheers

GONE

I'm giving away a centre speaker and a pair of floorstanding rear speakers. Pick up only in the Newcastle NSW AU area.

Centre: Vifa NE19VTS-04 + SB12PAC25-4, Vb=5 litres, F3=71Hz, 417mm W x 142mm H x 200mm D, 2nd order xo, comes with spare tweeter, grey grille cloth, oak timber veneer, birch ply top.
Rear: SEAS 27TFFC + Peerless 850488, Vb=7.3 litres, F3=60Hz, 270mm W x 416mm H x 140mm D, classic series xo, grey grille cloth, designed as mirror pair (tweeter out) to sit beside the sofa, beech timber veneer.

SOLD

Before I list this on eBay I'm listing it here for $150.


For sale is a 10" Subwoofer based around the Peerless 830452 XLS driver with a Parts Express 300-793 Subwoofer 250W Amplifier with remote control. This is side firing to the left and the B&W dimpled FlowPort is down firing. Made from Tassie Oak veneered MDF and both the inside and outside are sealed with a polyurethane finish. Cleats are used in the corners and the baffle is braced behind the driver. Comes with the remote control, IEC power lead and the amplifier manual. Used in a HT system in a 4.2m x 5.7m room with 2.4m to 4.2m ceiling height and provide plenty of bottom end for movies and was used at sensible levels.

Vb=40 litres, F3=27Hz, 376mm x 376mm x 476mm high.

Pick up only in the Newcastle NSW AU area.

Hello all!


I've been given a NAD C315BEE by a friend on the vague hope to repair it. From my diagnosis there is a distortion/muffled sound on some sounds. It's much more noticeable when the music has more sounds (ie. playing a sequence of sine waves from a youtube video from 10Hz to 20K Hz does not cause a problem).


All the inputs suffer from the problem, so I ruled out the input multiplexer circuit. The problem is also consistent across the full volume range so I also ruled out the power amplifier. Also, it happens on both channels.


I'm very dumb in terms of electronics but I started poking around and decided to test the voltages provided by the PSU board. From my tests the multiple voltages provided by the PSU board are ok (-45/+45V; 8V).


I then turned my attention to the +17V/-17V circuit (service manual, page 17) I noticed that the +17V rail is OK BUT the -17V is reading -1V ! (Amp on, no speakers connected, no inputs). Also the 5V regulator is working fine. I took the measurements between J169 (DGND) and J13 for +17V and J90 for -17V



For reference:



I measured +35V and -35V on the right side of the circuit, so that rules out the big capacitors after the full bridge rectifier. So, this leaves me with the -17V rail and I'm at the limit of my electronics skills here 🙁



I removed C330 and C315 for ease of access which appear ok (I'm unable to measure 2220uF with my meter but since the -35V rail is OK the cap should be ok too).


I then removed the capacitors from the left side: C308, C309, C310. All checkout fine. I finally removed the Q305 transistor but I'm unsure how to test it.



So, I would like to ask for your assistance. What can I test, is there an obvious culprit for the missing -17V? Should I replace all the bottom transistors ? (Q305, Q307)? Should the top part components also be replaced?



Something appears shorted here but then again I'm measuring -1V between the -17V rail and GND which (I think) rules out that possibility


Thanks!

I want to replace an iPhone 5s that does a good job of recording far-field sounds with its MEMS mic and +10.00 mic gain. It is probably doing AGC and noise cancellation.

I could get a Zoom H5 with a Clippy XLR ECM mic (Primo EM272 capsule) using phantom power to provide 8v to the mic or the Clippy ECM mic (same capsule), but only 2.5v from the mic/line input port of the H5.

Or I could get either of those mics, but use a single-board computer connected via USB to a Scarlett Solo or RODE AI-1 audio interface that connects to the mic via XLR or instrument port.

So far the budget portable recorders don't provide the Clippy capsules with enough power via the mic/line input port (Zoom H1n 2.5v, Sony PCM-A10 3v).

The Zoom H1n with onboard mics is not good enough to replace the iPhone: low audio levels (+39dB mic input gain) and noisy XY mics.

I see that on Rod's ESP site, he measures his MOSFET amp as having noise of <2mV RMS (unweighted -54dBV). A voltage seems to be a sensible way of measuring noise, but I'm not informed enough to know how this value compares to the SNR quoted on most commercial amp specifications (e.g. 116dB), so i'm struggling to put it into context. I realise this will be an incredibly basic question for many of you, but for thicko here is it comparable or convertible in some way? Or is it good/bad/indifferent?

For those of you who have built your own version of these, I'd also be interested to hear if you felt it was quiet or noisy compared to other amps, and if you made any mistakes or improvements etc related to noise/hiss/hum and so on of the completed amplifier. Obviously there'll be other sources of noise too (interconnects, upstream equipment etc) but this question is particularly about the amp (and PSU) built to Rod's official guides.

I'm interested in this particular amp because I already have the official PCBs and most components, bought some years ago but then never built. I'm trying to decide if I'd want to build and use it for my next application: an active configuration involving potentially sensitive drivers rather close to the listening position. In this case it seems very likely that noise of lower levels than normal might become quite audible, and I really dislike hearing it.

Thanks,
Kev

Say you have a biwire speaker with a low freq section with a 4ohm impedance, and mid/tweeter section 8ohms. You biwire it to a tube amplifier that has both a 4 and 8 ohm winding, connecting the speaker sections to the appropriate transformer output terminal.

What's the effect?

Amp came in stuck in protection mode .

I pulled the output driverboard and the amp powered up .

Amp is producing +- 12 volts to all opamps .
Amp is also producing rail voltages .

Any ideas where to start checking ?

Looking for $50 + shipping, which may be at least $20.

Hi I would like to sell my lovely AYA4 (2018) fully built-up by Audial. It is the model with USB to PCM input and SPDIF input
The condition is almost as New
220V input

Euro600 for your consideration, shipment will be depended on where to post to.

Last year during first lockdown, I build a TAS3251 Class D amplifier by joining a project of DIYA member JMF11. This amp is named NetAMP, build threat is: [design log] Neat 2x170W I2S in, I2C controlled, integrated DSP amp (TAS3251).
I was very happy with the result and decided to use it as my main amplifier in the living room. I then decided to build a preamp, then an enclosure. One design goal was to have something user friendly (easy to use) intended to all family and friends usage.
As the project as reach a point where I can confirm it is viable, I can publish information and progress in this thread

NeatAmp Pre handle:

• Remote management of NeatAmp board, including fault and error handling.
• 7 sources: 2 spdif, 2 toslink, 2 Bluetooth (1 open and 1 dedicated as a bridge with the TV), and 1 USB.
• Bt sources are 44.1 or 48k, spdif and toslink 44.1, 48, 88.2 and 96k and SUB will be 44.1 or 48k.
• IR receiver (NEC & Sony protocols).
• UI made of an OLED display and two rotary encoders.
• Soft start / power control for the SMPS.
• User presets memories.
• Auto power-off.

NeatAmp Pre allow user to manage:

• Volume, Mute, L&R balance, mono/stereo, DSP presets, balance of the input level of each source, IR remote code learn.

The block diagram shows Pre is made of four different boards: one for the rear panel with the inputs connectors; one for the front panel with display, IR receiver and encoders; one for the main board and the last for the power supply controller. This design mostly address large enclosure, this choice was dictated by NeatAmp board size and also the SMPS size. Boards are connected via flat cables and JST connectors.

NeatAmp Pre is built around a STM32F303, an AK4118 and two CSR Bluetooth modules. CSR, now Qualcomm, provide AptxLL (Low Latency) codec which is required for TV sound.

Power distribution is a bit weird, during development I encounter overheat issues on main board +5V reg and I installed a pre reg on the front panel board. This could be simplified.

NeatAmp Pre manage NeatAmp through a serial link. For this purpose, NeatAMP receive a specific software which manage low level TAS3251 duties including error management and communication with NeatAmp Pre. NeatAmp Pre also run its own software. Both software are made with ST suite: STM32Cube, they’ll be available on GitHub once acceptable quality level reached.

Current project status is ongoing, but everything now is stabilized and is viable.
What remains to do?:

• Power controller board. I am not satisfied with the current one, I’m currently switching to something closer to the one of Mark Johnson with an ‘always on’ supply made of a AC/DC converter module. I’ll update later when tested ok.
• Software modules:
  • Storage and management of the DSP presets
  • IR Learn
  • Shut off screen
  • Some minors enhancement
  • USB Audio (will be made last after the enclosure)
• Make an enclosure.

Block diagram is attached.