I am not discovering too much information on PARC Audio Components, especially Polyprop Cap's.
Is there any members who may have used them or know how they compare to other Brands Polyprop's that are rated.

Hello,

I would like to be able to take better speaker measurements and am wondering how I can do so with a limited ceiling height?

Outdoor measurements are not practical where I live due to either weather or too much environmental noise.

Has anyone successfully taken the corner of a room and setup sound deadening materials on the ceiling and floor to allow an impulse response much greater than 4ms in a room with only 7' ceilings?

I was thinking of something like 6" of Safe'N'Sound Rockwool in sort of an amphitheater configuration radiating out from one corner of the basement three meters (10 feet) in all directions with the speaker stand 1 meter out from the corner and the mic 2 meters out from the corner.

Another option was to do the same sort of configuration with large acoustic foam triangles.

Or, if the ceiling and the floor are going to be closest reflections between the speaker the mic, just place the speaker and mic twice the distance from the walls as the distance between the speaker and mic and just treat the floor and ceiling between the speaker and mic.

Don't know if any of these ideas would work or if they are dumb.

Anyone taken any significant steps to improve indoor measurements?

Thank you,

David.

Checking a whole bunch of tweeters. Here is a comparison of (1) a ceramic tweeter with a fancy horn that bought for can$3, maybe 50 years ago and (2) a Fostex planar (may have been in a top-end Infinity) with model number E110, looks similar to some at Madisound for us$700.

FR and distortion. Green trace is ceramic, not that you can tell the difference in traces.

Impulse plots look similar too.... believe it or not. But ESL trace better.

Glad if anybody could tell me what is that Foster tweeter. Pictures will be posted later.

B.

Hey guys, ive found a seller in my country that has LM3886T chip amps for sale but... im not really sure if these are original or chinese copies. To my understanding National Semiconductor doesn't exist anymore so any new unit of these should be TI branded, right?

The "French New Wave" is now dead with the passing of Belmondo.

Jean-Paul Belmondo, Magnetic Star of the French New Wave, Dies at 88 - The New York Times

I finally got my speaker rebuild together; 15" Eminence Kappa 100db/W and a PSD2002 105db/W. I was warned that I might need to put an L-pad on the compression driver an it turns out the the HF is about 6db bright. So I'm going to make an L-pad using aluminium cased 100w resistors (possibly over kill but.... ). Should they mounted to a heat-sink?

searching one or two of the Ian Canada CCHD957 adapter kits

Regards

Jo

Tonearm AUDIO CRAFT AC-300 o AC-3000
Some of you use this vintage but beautiful tonearm, very very good object for best audiophile music?
I search of understand the difference for the 2 model …..
Specifications for the 2 model are same ( vinyl engine web )
Effective length: 237mm
Overhang: 15mm
Mounting distance: 222mm.
I have a “ Van den Hul The White Beauty MC Moving Coil Cartridge “ and think that “AUDIO CRAFT AC-3000 with MC-S” is the model correct for me.
What do you think ? Thank for all answer.
GP -- Italy

Hi chaps,

anyone got a schematic of the second edition (black faceplate) of the Screamer 50 head?

Any idea if its a fixed bias or has trimpots? Mine started sounding aggressive after retubing and I suspect some tubes are not comfortable in there 🙂

When using 5" Satori MR13p midranges with a ribbon or AMT driver what is the maximum spacing at a 3khz crossover?


I am looking at the Aurum Cantus AST25120 Aero Striction tweeter (6.3 inches or 160mm)


And the RAAL 140-15D ribbon tweeter (7 inches or 180mm)


So looking at a MTM spacing of 6.3-7" or 160mm-180mm

As part of my dissertation, I am researching the acoustics of 'rave' / heavily amplified drum and bass venues and their PA systems.

I am looking for recommendations on PA system designs that are able to handle this genre of music and also sound good, obviously.

Take your average 1,4" inch compression driver and put it in an undersized horn, you'll still typically get a natural rolloff at about 500-600 Hz.

Other than the horn losing pattern control this low, is there any other reason not to make use of this extension in a home setting with a brick-wall high pass filter at say ~400 Hz?

Gracias. (Lo siento por mi ingles)

Hello,

I am trying to figure out how to add a subwoofer output on my Simple SE. I have marked up one of the wiring diagrams to show what I believe is correct, but I am hoping someone can let me know if what I am proposing will work? I added a few pics of the finished amp for good measure.

Thank you in advance,

Bassy

I recently got a Philips CD 204 off a flea market and it is indeed working.

It has problems with the tray, one of the gear (made with the infamous Philips orange plastic) has all of it teeth shaved off and the belt is worn, but I have ordered replacements for both.

On first test there was minor distortion on the RCA output and severe distortion on the headphone output. Replacing two axial blue Philips 15 uF capacitors fixed both problems and it now sounds good.

My problem is that the boards are full of those blue axial Philips Capacitors and I guess many are now quite out of specs. Is it worth a full recapping ?
My concern is that the boards are 35 years old and unsoldering an resoldering several caps might cause more harm than good. The power supply uses higher quality Nichicon caps and I hope they are in far better shape than the blue Philips.

Any suggestion ? should I keep it as it is until it is running fine or should I replace all blue caps ?


thanks

Hi fellow enthusiasts,

a dream came true and I was able to buy a set of 1966-1967 Trio/Kenwood TK-400 early solid state amp and TK-500 SS/tube tuner. Both units came as "defective". Upon opening the amp, the reason became clear for this unit at least: All output devices gone. One channel had both emitter resistors burnt. Many chassis screws gone.

Apart from this no visible damage. So possibly after the magical smoke someone sold the two good devices (or all 4???), Sony 2SD46. Someone (else?) had also veneered over the ventilation slits in the cover... a long time ago though.

I call myself lucky that all the PCBS are in place. Hopefully the pair of rare germanium PNP drivers, 2SB421, is still intact. Did not test anything so far. This amp is a late version of which no schematic is findable on hifiengine; it is quite similar board-code wise to the TK-80U receiver from the same time.

When the TK-400 came out in 1965, it was a full Germanium design with doubled output devices; subsequent iterations saw less and less germaniums, until this version which keeps only the two poweramp drivers Germanium (as in a couple of kenwood amps and receivers even into the 1970s, like e.g. the KR-33L).

so my questions are:

1) what size of screws is used to fix the devices to the heatsink? I tried M2,5 headset screws and they seem to work. They seem to need an insulating tube in order to not touch the heatsink.

2) What size are the smaller chassis screws? M3 seems to big.

3) What size are the screws to fix the bottom cover?

4) Is it a good idea to use NOS RCA N3055 devices as replacements? or too slow? I have also a set of new on semi TO-3s from mouser (MJ21194G) from another project (thank you, @Mooly) and might ultimately use them, but they seem overspec'ed, and I'd love to finally use those 3055s lying around.

As it is a single supply amp (-68V), and the 3055 datasheet says |Vce|: 70 V, maybe a bit tight? But maybe I am not completely understanding the specs here.

Some also say the 3055 sounds bad or is not truly intended for audio use. The venerable Revox A50 used them. The SD46 has a much higher ft though.

thanks for your input!
eschenborn

Hello there, I wonder if anyone can help with the service manual for this model ?


I already have the SPA22 (a 40 page document) but I need the HD version which has slightly different boards



Thank in advance , Mike🙂

Hello.
Guitar amplifier HUGHES & KETTNER ATTAX 100.
No sound.
All voltages 15v,-15v,18v,-18v,45v,-45v are ok.
No blown fuses.
If I connect my guitar on FX loop return,the sound ok,but only clean.
This Amplifier is build with one tube 12AX7A on preamp section.
How I Can veryfied this tube or control other elements.
Thank you very much.

Service manual.

HUGHES-KETTNER ATTAX 100 COMBO Service Manual download, schematics, eeprom, repair info for electronics experts

new. never mounted never used 189 shipped conus

Purifi 1ET400A / Hypex NC500 Input Buffer – Neurochrome

Given the limitations of tube rectifiers in terms of current, is there any reason why the tube rectifier isn’t used to drive a (or pair of) bypass shunt triode?

The bypass shunt then allows when he AC waveform allows, additional current to be supplied to the B+ rail without going through the rectifier? The triode is shut off before the rectifier itself passes zero transition.

hi there could some one please check there arn't any obvious errors in this, copying from my amp build of 3 years ago. which i want to clone but lost the original schematic. also changing from 6sl7 to 5751 so may have to change cathode values, sugestions welcome

Yes, I know, not everybody’s cup of coffee, but…

Brushy One String | Chicken in The Corn (Official Video) - YouTube

I am selling my diy Aleph J amplifier. The amp works and sounds great, but I am trying to recoup funds for other projects. Built using the DiyAudio store boards and 4U chassis. Asking $500 plus shipping from Ohio. Package dimensions approximately 24"x24"x16" and 45 pounds. I can only ship to US addresses due to previous issues shipping items internationally. PM me if interested or any questions!

I need a set of files preferably real fine diamond grit or an extra fine standard metal file will do. They need to be very thin like 1mm thick and no more than 2mm wide and it would be good if they came in different shapes.
I’ve been gluing sandpaper to business cards and cutting it to shape for repairing equipment but that is a pain and it doesn’t last long at all.

Is there any good quality files out there diamond or not that are extra fine at least P1500 grit or higher? Don’t care on the price I just need very high quality ones that work and last the time (hopefully)

OR I could make my own?? Find super fine diamond dust but I don’t know what glue they use to attach it??
Cheers

But I do not want to use PAYPAL.
Some time ago, a Company on the Web, Cheated me for some amount of money.
I paid using PAYPAL. When I knew that they cheated me, I made a complain, to PAYPAL, but instead of sending me my Money back, Paypal wrote, that they think that that company did not FAIL or did anything wrong.

I paid EXPRESS CHARGES Of 20Euros, for a shipment from good old England. On that Page, it stated that items would be sent, the same day the money has been paid. My money had been paid, on a Monday but the Items I bought were not shipped for another 7 days.

After my complain to PAYPAL, and their answer, I removed my account for PAYPAL and I WILL NOT USE THAT SERVICE again in my life.

That Company which sold this Items have hundreds of complains, similar to mine. And if PAYPAL thinks this is right what they do, since then PAYPAL is DEADPAL for me.

I really would like to Donate some Money to DIYAUDIO, I'm not interested in any benefits, it's just Because this site helps a lot of people, and that's why.
But if you haven't another way to pay then, I need to say I'm sorry, each and everytime I try to donate, the DEADPAL SITE comes up, and I stop right there.

NO MONEY with, through or FOR PAYPAL.

Tell me if you have another way to make a donation to you. @DIYAUDIO whom it may belongs.

Regards Chris Hess

I've got a fair bit of free time coming up, and I thought I'd code an inventory management desktop application to keep my skills sharp. I know there are existing offerings out there (like PartKeepr, Bomist and PartsBox), but I've found them all to be either expensive, ugly or lacking in features that I need. Plus it's been ages since I've coded anything similar so it should be fun. Once I'm happy with it I'll make it available for anyone to use.

It's not going to be super complex, so no CRM, ERP or online integration type stuff. It won't require a web server (which adds flexibility, sure, but I just don't need that) or SQL installation.

Basically, a straightforward standalone portable application one can run on a workbench laptop or PC. One could always stash it in a DropBox or Google Drive folder if you need access to it from multiple locations.

I know what I need from it, but if anyone has specific requests for functionality I'd be happy to add it (within reason 😀).

So: what would YOU like to see in such a program?

Can anyone tell me what they know about this amplifier? It is made by an Italian company and supposedly, their amplifiers and speakers are audiophile grade. I have personally never heard of the company but they make some “good looking“ amplifiers. Amplifiers

The current amplifiers on their Website seem to “look” great but as everyone knows, looks can be deceiving! I have attached a picture of the amp in question.

I am thinking about purchasing it, I am currently in the market for an affordable class A/B 4 channel amplifier for latest SQ build. Ground Zero, stereo integrity, tru technology, and genesis amplifiers would all be a great choice IMO but the price is a little steep.

Hi, anybody knows what the jumper j1 and j2 do? They are placed near the chipset of anagram board, inside an Orpheus dac one. I enclose picture. Thanxs

I'm finally getting around to my first build. After much thinking and for complicated reasons, I've decided to build four 2X12" ported boxes. Front-mounted, possibly push-pull.
(I'll build smallish horns afterwards, probably a 15" Keystone, and will then compare them.)

I'm trying to pick the optimal driver, and am still a little shaky on certain T/S parameters, especially as they relate to box size and to a ported design vs a horn..
I'd REALLY appreciate some opinions:
--------------------------

I’d like to get the Fb as low as possible. My truck dimensions will allow me to have a Vb of around 4.5 ft/3 to 5 ft/3. Maybe even a bit more. I assume that will get me fairly low, and also increase volume output. I’m thinking a large Vas, plus a low-ish Qts for good control in the large-ish box. Is that correct?

I will be crossing over at around 100 - 120 Hz.

I’ll be using 1 lb of fiberfill per ft/3 of box volume, unless someone has a different recommendation.

The driver must have an alnico magnet, for light weight.

High power handling is not so important, but efficiency is, since most of my gigs often only provide me with one 15a outlet (20a is a luxury.) Therefore, I think a 500w rating per driver is probably enough. However, if you think a higher rated / less efficient driver will sound better, then of course make that your recommendation.

Just looking at B&C for now, I’m leaning towards their 12NW76, due to its low resonant frequency & its high efficiency. It has a high Vas at 2.7 ft/3, so (I think) a 5 ft/3 box should work great with two of them. Yes? Unfortunately, the Qts is somewhat high at 0.41. Is that a problem with a 5 ft/3 Vb?

Would you recommend something different?

For instance, the B&C 12NBX100 is a bit less efficient, and "only" has a Vas of 1.8 ft/3. but it has a Qts of .22.
===============================================================

Related Questions:

#1:


#2: If I go with a driver like the B&C 12NBX100, which has a Vas of 1.8 ft/3 or less, can I still build boxes with ~ 5 ft/3 Vb so as to get a low tuning and good efficiency?
- Or are the trade-offs not worth it?
I've read that it's "safe" to have the Vb as much as 2X the Vas, but I don't know how accurate that is or (again) what the trade-offs are.

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

I need to make these boxes an unusual shape, if that is workable. This is because I need to fit four of them into a small pickup truck, and I want to maximize the Vb while still fitting them easily.

My ideal external dimension is 13” deep x 42.5” x anything at or larger than 21.5” This will result in only about 5” from the inside-back of the cabinet to the driver’s magnet. (or to the speaker surround, in a reverse P-P mounting.) Even less if I put damping material there.
I don’t see why this should be a problem, as internal volume is internal volume, but I’d love to have an “official” OK on this before proceeding.

- For instance, could this possibly cause a problem due to limited port depth?

Hi,
I'm having a tough time getting Hornresp set up. I'm not a computer person, just like to use what is already working, like a calculator or a typewriter!
I'm in Toronto. Would anyone in Toronto be willing to show me how they have installed Hornresp and give me some tips on how to operate it?
Thanks,
Dwight

Hello!


I have an active 3 way plus sub system.

The drivers are
2x Acoustic elegance ib 18 sub
2x acoustic elegance td 15 midbass
2x AudioTechnology 4H52 'FlexUnits
2x beyma tpl 200

Drivers firing upwards
2xVisaton ti100
2x b&c de250

Electronics are
Streamer pc
RME adi 2 dac
Behringer dcx2496 le
Behringer crossover for subs
5x Behringer A800


I crossover at the following frequencies
40hz
340hz
3300hz
LR-48

Many people say passive crossover sounds best and I want to find out for myself.

My plan is as follows
*Make a passive crossover for tweeter and midrange
*bypass active crossover for midrange and tweeter
*get a more advanced amplifier to run midrange and tweeter


I like all my drivers very much
The beyma tpl200 amt is very nice and derailed but it gives a harch sound if not crossed over very steep.
It also sound hard if crossed too low.

The flexunits is very smooth and nice, just like I want it.
The sensitivity differs 10db so it could be hard to design a crossover.
Impedance is 8ohm both drivers

My options so far is
*Buy a new midrange with higher sensitivity
*buy new tweeter, perhaps beryllium with low sensitivity
*buy another pair of flexunits midrange and parallel them to make an MTM in order to increase their spl.

I like the last option if it's possible but also fun to try something new.

What do you think is the best choice?

Best regards Marcus

I'm going for a 6db time/phase aligned (centers lined up too) mtm.
like dunlavy sc1 linked below, but larger woofs and slightly lower crossover point.
Dunlavy Audio Labs SC-I loudspeaker | Stereophile.com

I'm fixated on morel cat378 horn/dome, i have 4 collecting dust.
Morel CAT378 Horn Tweeter
MOREL CAT 378 Soft Dome Horn Tweeter – AmpsLab
With its 5.6uf it is 6db down at 2khz and 12db down at 1khz.
I had good results running it back a couple of inchs with a 10" eminence b102 (run wide open).


So I've been looking for around 92db woof (8" for a 2-way), or 86db x2 (8ohm) mtm wired in parallel.
Needing a flat impedance curve also.

The rival acoustics 7" woofers (made in Canada, sold by RAD (rhythm audio design)) have copper cap, making for an easy inductor 6db crossover.

Kevlar (looks smooth)
Lowest Price for Kevlar woofers by Rival Acoustics – Rhythm Audio Design

carbon/paper has a big resonance that a notch may not help much (mixed with 6db crossover)...………..
Paper woofers by Rival Acoustics – Rhythm Audio Design


Thoughts ?

As the title states, I'm considering building the Zaph Audio SB12.3 but with a ported alignment for the woofer. The WinISD model says I can put a port in the same size box for an F3 of about 27 Hz instead of 37. Cone excursion looks good, port velocity looks good, I'm not really seeing a downside. I wanted to check if I'm missing anything, or maybe if something needs to change in e.g. the crossover design.

I have been building up the driver circuit for the Morgan Crystal Palace Amplifier. I am perplexed how the Cathode Follower works in this circuit. In my tests, the input to the grid of the cathode followers (shown circled in the attached image) is 170Vpp (58Vrms), 1kHz, and the cathode output is 160Vpp(56Vrms). The grid is biased -8V (90V-82V).

Since the grid is only biased at -8V, why doesnt the output get clipped when the input voltage swings beyond the -8V? What is the physics explanation?

I'm messing around with DSP, and at the end of it I'll build some nice active three way speaker - digital from source to individual power amps.

Except - I'm wondering, with modern drive units if there is actually any benefit in going three way? Especially since DSP means you can shape the speaker response curve.

Part of the logic of going DSP is that you've lost the dodgy crossover stuff and hence you you can keep adding units at no quality cost.

But there is still the audio cost of the signal chopping from one speaker to another.

I've decided on SB Acoustics units. Their six inch bass mid - SB17NBAC35-8 - seems to be a better performer than their slightly smaller units. It's also cheap. I'm wondering if adding their 9.5in bass actually achieves anything useful.

Options are tweeter, 6in mid, 9.5 bass (the default choice).
Options are tweeter, 6in mid, 9.5 bass, single sub.
Tweeter, 2x 6in mid, single sub.
Tweeter, 6in mid, single sub.

Tastes are wide, but I listen to a lot of loud rock in a very big room.

Currently using EPOS m22s, and very happy with them. This is really about messing with DSP.

What's the current thinking on numbers of units when cost isn't a major concern?

It could be possible totally bypass the input stage in the famous Sun Audio 300be?
I use it with Headphones( Ergo AMT) and I would like to reduce at real minimum the noise.
I use source with low impedance output.

Is possible also try different Tubes on the sun audio 300be?
I know many try to transform 300be in 2a3 version.
It could be possible the reverse?

JL AUDIO 300/4 Amp Repair

Been attempting to repair two 300/4 JL Audio Amps. Kind of a hobby with little working experience.

I have two old school JL AUDIO 300/4 amps that i purchased dead, and after identifying dead output FETS, ordered parts and replaced each row.
Output and PS resistors checked out ok. All 4 output channel vertical boards have green LEDs lit.

low current bench test: 12V, w/1-3 amp current limit set. Both amps green light. But it appears a feedback loop constantly resets amp.

The wierd thing is that both amps are doing this reset loop. What are the odds that both amps perform the same way. Turn on, green light on, play distorted music for 1 sec, then silence. Wash, rinse, repeat.

What should I look for? I feel soooo close yet sooo far.

Any suggestions as to what might be next to study/observe would be greatly appreciated.

I do have a scope and can see a steady square wave on the PS rectifiers (when rectifiers are removed, when they are on board, amp does a reset loop after about 1 second of distorted sound)

Looking for a new build, something higher-end and SS... started my journey with a iMod mini, CMOY, SSMH, Gainclone, Mini3, Gamma1 and a SOHAII.

At the time I was using HD580s, which have since been sold and will be replaced with HD600/HD650/HD6xx one of them. I'm also interested in planars, maybe the Sundara.

So I haven't built an OTL or higher-end SS headphone amp. Considering building the latter and I wanted some ideas on what I should pursue, given what I've built and hence something "technically" better.

So thinking of builds based on some perusing:

• O2
• MilletMax
• Whammy
• M3
• Beta22 (2-channel)

I'd like to keep the cost sub $500, though I'd have some room for something exceptional. Please, open to suggestions.

On a tangent, I hear Bottlehead Crack or SEX mentioned a lot for OTL... thoughts?

Greetings to everyone, I like to study amplifier curcuits but electronics is not my main activity. In this case I'm simulating a class H amplifier, I did simulations in Multisim and LTspice, I would like to know why the waveform in the differential pair transistor collector is deformed? Thanks in advance for the responses.

Hi,

Please does anyone have a practical experience with AK4493 in oct or hex sampling speeds, i.e. 384+kHz sample rates?

When MCLK is at least 128xFS and sampling speed (DFS0-2) at most quad, the DAC outputs correctly oversampled signal. When dropping MCLK to 96xFS and setting corresponding sampling speed to oct or hex, the DAC output waveform is broken.

This is 96kHz sine generated at 384kHz. The chip officially supports MCLK 49MHz, hence I can set MCLK=128xFS and the corresponding quad sampling speed. The output waveform is flawless (fig 1), detail showing the oversampled steps at fig. 2.


However, when using MCLK = 96xFS (correct ratio according to the datasheet http://d.zaix.ru/5cHC.pdf ) and the corresponding oct sampling speed, the DAC output waveform is broken (fig 3, fig 4).

The same occurs for the hex sampling speed (e.g. at 768kHz or even at 384kHz with MCLK = 64xFS). I am surprised nobody would have noticed such a weird behavior, but have not found anything being discussed about this. Well I have not found any technical discussion of using these chips at fs > 192kHz (but they are used in commercial soundcards supporting up to 768kHz). I asked at eevblog, no response.

Thank you very much for any hints and recommendations.

Pavel.

Hello,

I wanted to connect Genelec active speakers to computer and I didn't want an extra power brick or cables around. I didn't find any comercially available, so I made one.

In case the files can be helpful to someone else, I published it on github for your pleasure.

I finally broke down and decided to put all my resistors in one place and in order. Between 12 or 20 different projects it was getting very hard to find what I needed, searching between all those boxes. My five year old son even helped label a bunch. 😀

I am used to Voltage Feedback design but wants to get into Current Feedback Design but their some problem.



Most CFA example i can find a diamond buffer based ,which are known to cancel 2nd order distortion , which are the last thing i want.

I want to start this thread so that i can get introduced to some CFA input state design. 🙂

Typical center channel speakers have never really worked for me. Typical flat screen TVs force you to place the speaker above or below and then you try to angle the CC speaker so you are not always listening off axis. Then there are BR ports that exit the backside making it hard to place them in a TV stand or against a wall. A lot of them (my Paradigm CC370-v4 included) are 2way MTM designs that create off axis horizontal lobes because they XO to the tweeter at high freq.

I'd like to design a CC that is better suited to how I will use it and still work with the rest of my HT system. The room is being renovated, and the CC has to suite the new location (a fireplace column) as best as it can.

The fireplace column will hold a direct vent gas fireplace (Valor Linear + Heatshift kit convection cooling), a 48"x36"x8" pocket for a VESA mounted 50" TV and a center channel speaker. The pocket includes ~5" air space behind the TV (when flush) for convection cooling.

Versions :
V1 : 2x DC130B-4 + CX120-8 Coax : V1 : 2x DC130B-4 + CX120-8 Coax
V2 : 2x DC130B-4, PT6816 Planar : V2 : 2x DC130B-4 + PT6816 Planar
V3 : 4x Dayton PC105-8 : V3 : 4xPC105-8
V4 : 4x DC130b-4, PT6816 Planar : V4 : 4xDC130B-4 + PT6816 Planar
V5 : 4x DC130B-4 + 3FE25-8 + TD20F : V5 : 2xDC130B-4 + 3FE25-8 + TD20F

.

I've bought a load of these and they are genuine.

2SJ74 Toshiba J-FET Transistors QTY 20 - 2SJ74GR - NEW UNUSED - Audio Low Noise | eBay

Hello!
I see people talk about the Onken for EMS B15EX, is the Ciufolli Onken design suitable for this field coil drive unit??


Hi-End and Hi-Eff loudspeakers system

Hi-End and Hi-Eff loudspeakers system 2

Thanks!

Does anyone know somewhere that has stock of genuine JRC5534DD?

Mouser and Digikey etc are showing them as 'no longer manufactured'.

I should add that I'm not interested in 5534's produced by TI, On-semi, Philips or Signetics.

Thanks

I'm refurbishing an old NAD amp and am wondering if I should replace the ceramic disk caps along with the others. Do they age? Does it make sense to replace them with a different type of cap?
Thanks 🙂

I have a commercial phono pre which one is suitable for MM and MC. I don't use MC and never will. In the first stage there is an OP37G used. For my own reasons i want to use a 5534. I am a fan of these with MM and have different brands.

But can i drop in the 5534 with no problems for the op37? In the rest of the cirquit one opamp is used for Riaa and one for IV with pot resistor for offset.

And if so, can i get away with no compensaton cap? What will be the gain of this stage, the 5534 is stable until 3x with no external cap.

I have read about how a ground plane is not a perfect ground and i should connect output gnd to a quiet gnd point then i have a question:
Assume that the rectangular is a solid ground plane. If a current of 1A must flow from gnd load (point B) back to gnd source (point A) and assume that the resistance between A and B is 1R, then a voltage of 1V is developed between A and B. But then what is the voltage different between C (an arbitrary node in ground plane) and A or B? If we measure between A and B we will get 1V but between A and C there is resistance but no current flow so voltage difference between A and C, also B and C will be 0V different, isn't that mean between A and B there will be 0V different?

Hi all. I'm taking inventory of what's in my storeroom after 10 years of tireless R&D, and selling it here in the DIY community because this is where it belongs. Long live we who build!

I'll be posting front-end equipment and amps as well, that's next. All the miniDSP's from my previous post have sold.

Please email me, instead of messaging me here. I love DIYaudio but the in-site messaging system here is from the Jurassic period, it seems. 🙂

db@aforara.com

Many of these woofers are backordered / hard to find. They're all in either new or like-new condition.

Pricing begins at 15% off retail (and no taxes). So multiply the below prices by 0.85 to determine my price.

I'll ship 'em. I'll continue to discount whichever ones don't sell.

• B&C / 21SW152-8 / Qty: 4 / Retail: $780/ea
• BMS / 18N862-8 / Qty: 2 / Retail: $580/ea
• Eminence / Omega-Pro15A / Qty: 2 / Retal: $210
• Fi Car audio / IB318v2 / Qty: 4 / Retail: $275
• Tone Tubby / DD 12" Hemp / Qty: 2 / Retail: $225
• Eminence / Alpha 15A / Qty: 12 / Retail: $80
• 18sound / 15NLW9500 / Qty: 2 / Retail: $400
• SB Acoustic / SW26DBAC76-3-DV / Many! / $190

Reminder: email please, not an private msg. 🙂
db@aforara.com

While listening to the test cabinets of the Alnico CA-80's, I was simultaneously building the DUAL-208's.
Once they were finished I was very disappointed with the lower frequencies.
But in general very nice speakers for my 2nd set.

Hey Perry,

I have a Rockford Fosgate 240x4 that will not power up. I have checked all the outputs and powersupply fets are good. Amp seemed in decent shape. However, the U1610 and U1620R had burn marks and were missing the 2.7ohm resistors. I have applied power to the remote connection and connected the ground and only have about 0.412 vdc on the powersupply center legs.

Hi all,

I designed some weeks ago a small tool to improve my noise instrumentation setup.
In fact, when doing wide-band noise measurement (well beyond what we can simply do with a sound card),
is is more difficult to measure low noise level.
One way is to use RMS measurement with an oscilloscope, but scope sensitivity doesn't go much less than a mV...
My latest AAPSU01 low noise PSU design is an example that can achieve low wide-band noise,
and so building this small tool has been motivate first by that.

So in practical manner, it's a small shielded box that include a low noise, high bandwidth and high gain amplifier.

The design specs are :

• 20Hz to 20MHz measurement bandwidth (-3 dB)
• 4th order Butterworth low pass filtering.
• Individual +20 dB(x10) and +40 dB(x100) outputs BNC
• 12 Vdc@50mA input supply.
• Max input amplitude about 100mVpp (with 12V supply)
• Output noise floor RTI ~ 12µVrms (Equal to En= 2.7nV/VHz)
• Can handle +/- 20VDC input offset voltage (AC coupled)
• Zin= 50 Ohms, AC or DC coupled (internal jumpers)
• Fully shielded design.
• Low cost design (full bom <30€ + PCB)

The design is based on LT6200-10 OPAMP from LinearTech (now AD).
It's a very high speed amplifier with 1.6GHz of GBW product
and less than 1nV/VHz of spectral noise density.


The full schematics is here : WBLNA_schematics


You can show below some picture of my unit and some measurements results.

PCB Kicad 3D view :




Picture of the finished prototype :




100ns pulse test input/output result :




So, i have published this projects as open source and it is available
to download on the GitHub repository here : \OnEAudioProjects\WBLNA
The project has been designed with Kicad 5.0.2

All original design files are available :

• Schematics
• Bill of material (with Mouser order codes)
• Mechanical drawing
• LTspice design files
• Gerbers files
• Panels stickers print

and more...

So i hope that will interest some people. 🙂

(Note that i have few bare PCB's available(4) , anyone interested can get one
with the panel stickers for 6€ worldwide shipping included )

Regards.


Frex

Hi. I'm with this CDP-701ES. It has a lot of fails and bad attempts of repair. A long history. Now it works, and I hope this cd player can help me to repair and adjust OPH-31, 32, and etc... laser pickups.

Well, the problem. There is a Low Pass filter with a OP-AMP that makes a pop-pops sound. I've opened and cleaned of rubber, but there is a hard resint that is very hard to remove.
I've proved acetone, paint disolvent, nitro disolvent, alcohol, gasoline, air hot(with care), and nothing.
So, what can disolver this resin?

Best regards



Shared album - José Manuel Morales Hernández - Google Photos

Shared album - José Manuel Morales Hernández - Google Photos

Help me choose a Mid!

UPDATE AT PAGE 11
3way Studio Design


Hi all!!!

I am designing a system for Studio/Mastering duties and I am doubting about what mid-woofer / Midrange to use. I am looking for the most transparent & flat response among the drivers listed below.

A Mid-Woofer/Mid that can reach up to 3Khz as flat as possible, as my goal is to cross the tweeter around 3500hz.

I still have to choose what configuration to use MTM or a Classic 3way design...

I have in my hands:
x2 Eton Orchestra 11-612/C8/50 RP Woofers (91db sens) Fc around 380Hz
x2 Focal TC90TD5 Tweeters (91.5db sens) Fc around 3000/3500Hz


Options

For MTM

- Eton Orchestra 5-612 (88db sens)
- Scanspeak Classic P17WJ00 6.5" Woofer 8Ohms (88db sens)
- Scanspeak Discovery 15W/8434G00 Midwoofer (87db sens)

Is it true that I get +6db sens when summing two drivers? I actually measured this with two other drivers I have at home, in cabinet, and when summing a 2nd woofer, signal at 1 meter measures around +6db. But I have seen people here that swears its just 3db? I am confused about that...


For 3Way Classic

- Scanspeak Revelator 18M/4631T 7" Midrange (92dB Sens)
- Scanspeak Discovery D7608/920010 MidDome (92db sens) (used by PMC)
- Satori MW19P-4 7.5 Mid Woofer (91.5db sens)


Till know, I am leaning to an MTM design. Although I am also tempted with the idea of using the SS Mid Dome, but I don´t know if it can perform well at mid low frequencies. PMC says it´s cutted at 380Hz? But Fs is 300? pretty close :/

I would really appreciate some input.


Thank you all!

Does anyone run a 99.999% pure Silver Litz Cable to their 310A or 6C6 grid cap?
i.e. Glasshouse Interconnect HGC

If so, have you noticed any improvements or interference with only cotton sleeving?
Are you using .5mm or 1mm diameter?

Hello everyone . Is my first post here so... have mercy 🙂
I play with amplifiers and good music for too many years , i can't remember . The problems start now with all "digital era" .
Well... i can't say is bad thing but i just think will take some time to get back the real analog sound or i need some modif' in my system.
My setups aren't very complicated , Denon AVR2105 for movies stream from my TV and control everything in my home, for music Wangine WFA-220 , Denon POA2200 + preamp PRA1500 , all my speakers are Canton and sub Behringer .
All fit perfect when i listen music, analog source through AVR as controll (i don't use internal power of that amplif) or even optical/coax.
All sound amazing , but when i want to stream in my TV and "passthrough" audio on optical output going in AVR , everything change . The music sound crappy asf. Is like a joke to be honest comparative with any decent CD sources.
I try RF-line in Passthrough PCM option on my TV and i think is just a cover and post processing .
Still what i don't understand is , the movies sound pass DD or DTS with normal quality.
What i missing here ? I'm realy confused.
What i can do ? All i want is to stream music from tidal or spotify from my phone to DLNA and to get at least decent sound.
I was thinking to made or buy a HDMI sound extractor and convert to PCM , like that i can use internal AVR DAC's through optical input.
Sry for my english & Thanks
Bobby

SOLD

6 tubes, 2 briefly used
4 sockets, also 2 used

30 euros for all or send me a PM

Location The Netherlands

I saw a thread on here about Cinder Block Speakers and am very intrigued.

The block I am thinking about using

I'm fairly new to this and could use some help
Here is what I have mocked up so far



Couple Questions and Facts

The ~sealed volume of each cavity is .217 ft cubed. Should I go for a sealed enclosure or a ported. Based on my research a sealed enclosure is both easier and more forgiving. Looking at the gif they have clearly made an effort to combine both cavities which seems like the best course of action for either sealed or ported

Based on the size of the cavities, I think it makes sense to have a 4" driver. The Dayton Audio one I have looked at have a sealed vol of .18ft cubed which means (if i understand) that this cavity is actually WAY too big for those drivers? It would be even more mismatched if you added both cavities to the sealed volume. Any suggested drivers.

Crossovers: I have tried to understand the ideal crossover point but I really am missing something here and could use some advice. I need a crossover for each driver right? This is the tweeter I think makes the most sense Frequency response is 1,600 to 20,000Hz so does that mean I want to get a crossover between 1500 or 2000hz



For additional parts that I need:
Speaker Terminal
Already have speaker cable (14 gauge monoprice)
Gasketing Tape to make seals
Glue to connect wood to cement when complete.
Am I missing anything here?

Any help would be much appreciated. I have tried to do a lot of my own research but i'm very new and don't know what I don't know

Hi all,

While doing interviews and posting at diyaudio I've been secretly working on my own printed audio publication! 😉
I'm happy to report that Linear Audio Volume 0 is at the printer's and you can check out the contents and read article abstracts at Linear Audio | your tech audio resource .
The author line-up will sound familiar here and includes well-known diyaudio members like Joachim Gerhard, Stuart Yaniger, Nelson Pass, Douglas Self, Bob Cordell and others.
Let me know what you think of it!

jd

[ New thread split from here - tube preamp makes rushing noise at speakers]

Hey guys,
So the muting relay works great and the amp sounds good.
There's no hum or noise now.


So now to sort out the headphone amp. Perhaps someone has some suggestions. Right now there's a pretty loud hum in the headphones and the amp sounds distorted. Here's the schematic. The hum may be due to layout. The circuit board and input wires for the headphone amp are close to the transformer. I'm going to change the input wire to shielded cable. Hopefully that works.

Hello everyone,

I ordered two PCB's from Aliexpress some time ago for an active crossover project where i just needed a decent bass amplifier.



The design looked reasonable and at a price of like 2 bucks each they fit the bill 🙂



So i just finished retracing the board and it looks like a simplified version of the leach amp.




The transistors used are a little too expensive for my project, thinking about replacing the input transistors with a pair of 2SA1015/2SC1815, 1145/2705 to 2SB647/2SD667 and drivers and output transistors to BD911/912.

Any thoughts or idea's are welcome.

hi,




I have a denon DP29f turntable. are there any improvements possible in this kind. currently i get fairly loud sound such that my computer 2.0 channel speakers cant be pushed beyond half volume. else the sound distorts. whats really going on? the sound separation is good though and the detail i voice has improved after a adjusted the azimuth a little by hearing tests. this TT sadly has no other adjustments that i can make.. right?

would happy if anyone can give me a few tips o this TT and setting it up correctly.. I am new to using a TT.


thanks!

Amit

Hi
Tomorrow I am going to look at a 1983 Denon PMA 750 Hi Fi amplifier to purchase for my new set up. I'm intending to hook two subwoofers to it which will be powered by my new Crown XLI 800 PA amp

To do this I've already purchased some inline LFE LPF crossovers.

The Denon PMA 750 does not have a subwoofer out RCA on it so the input mismatch I am concerned about seems irrelevant. Crown XLI 800 has RCA inputs and selectable input sensitivity on it 0.775 to 1.4v It is made so it is compatible for home use. The Denon has an input sensitivity of 150mV (pic below)

Does the input sensitivity matter at all as it looks as if there is a mismatch in the specs below (PMA screenshot specs)

Im intending to use this method below as in screenshot, no RCA?



Denon PMA 750 input SPECS



Crown XLI 800

I really like the look of this design. Also the modular nature allowing you to

time align the boxes and also easier to move the speaker around. Just wondering

what the drawbacks to having each driver in a separate enclosure might be. More defraction? Will that show up in the frequency response heavily? Focal

also did this with the Utopia series. Another thing is arent the drivers slightly closer together acoustically this way being that they're all pointed right at the listener?








Here's the design link:

K+T 4-9-9

Hi, I got an nice JVC RC-90M Boombox with an issue with the cassette transport, when I turn it on, all I hear and see is the solenoid momentary going up and down. Nothing else working when I press Play, ff or rewind, the belts are all fine. Not sure if the capstan motor should be spinning all the time on this? I checked on pin 5 of IC701 when i press play it changes from 5V to 0V, so the play switch is working. Pin 18 = 5V as expected. I noticed on the output pin 14 when play is pressed, the voltage stays around 0.7V (no change when pressed or released) I also checked resistance between pin 4 and 8 / 9 and with cassette out it is 1.4kohm and in 7.55kohm so the micro switch that detects the cassette seems ok I think. I checked all the electrolytic caps and all ESR / capacity measure fine. Checked all diodes, and transistors (removed out of circuit) all seem fine. Fr702 =1425ohms, Fr703 = 4.47ohms, fr701= 5.31ohms, (need to confirm these are correct) I also temporarily disconnected pin 11 (power off reset) from the chip, but no change. Could this be a faulty (JVC VUC0002) IC701 chip? Any other suggestions what to check ? I see the photo diode led on. Hoping someone has had the same issue and that there might be a common "known fault" with these transports

Hello again.
A friend brought me a roland acoustic chorus ac-90. Amp is completely dead (no power when flipping the ON switch).
I opened it up (pain in the butt!) and checked power from the cord to the toroidal transformer primary winding. Tomorrow I will continue to search for the fault. It might be something stupid like a loose connector, or it might be more serious, like a blown secondary winding on the transformer. Who knows? I've seen both scenarios before on Marshall and Fender brand amps made in China.
Any suggestions as what else to look for?

Thanks in advance.

I'm in the process of going through an H.H. Scott 348 (not the "B" version"). One amp board is ok, but the other has two bad drivers: Q5 and Q6. Based on the fact that the outputs are both non-original 2N3055s (tested ok), my guess is that one or both of the original Bendix outputs on this side shorted and the person doing the repair never checked the drivers. Or not. . . . Regardless, I'm going to pull the board and check everything.

The failed Q5 and Q6 are what H.H. Scott called "QA-10" transistors. According to a circa 1980 SK catalog I have, this crosses to SK3024/ECG128. If I have to go with NTE128s, I will, but I could use input on a) whether there are any better options, such as the 2N3019, and b) how to address the color-coded grading that Scott used for these, which I assume correlated to hFE and possibly other parameters.

Hi,

I purchased this KT88 based power amp from a HiFi shop back in the late 90's. I had an article on it from a mag but have lost it.

All i know is....its 70wpc, made in Melbourne Australia and the plate is 24k gold.

Anyone have more info on Contan audio in general?

Picture was taken from a b/berry so apologies in advance!

Thanks

In remembrance of course. It's going to be a sombre sequence of events. Serious reflection in the near future likely.

I searched and didn't come up with much more than "it doesn't work". So I did some home work.

LT4320 is called something like an "ideal rectifier bridge controller". But the Figure 2 waveform in the datasheet shows it is a bit less than what you would call "ideal", in that the bottom FETs conduct over most of the input AC voltage cycle, much longer than the duration the top FETs conduct to charge up the output capacitor for.

Apparently such behavior results in the negative node of DC output gets tied to the bottom AC input node most of an AC cycle, and if we were to hook up a center-tapped transformer as well as the split-rail output capacitors, C1, C2, as we usually would to construct a full-wave split-rail PSU, the bottom capacitor C2 would be shorted out by the transformer windings through the bottom FETs during their extra conducting time period (hatched). This appears to be why "it doesn't work".

However, if we could somehow gate the bottom FET drives in such a way that they conduct and cutoff in sync with that of the top FETs', therefore, eliminating the extra conducting time, we probably could make it to work with a center-tapped transformer and be able to make a split-rail PSU with one LT4320.

I came up with a circuit as attached, for a 2 x 24 Vrms input. LTspice simulation indicates it would work just fine.

The 72V maximum voltage rating of LT4320 limits the use of the circuit to up to about +/-35V output. For higher output voltages we are out of luck but have to use two bridges and a transformer with fully separate output winding leads. Nevertheless for preamps and class A power amps that most likely operate under +/-35V, and especiall when having a center-tapped transformer flying around, this circuit perhaps is useful in either saving an expensive LT4320 and the four extra MOSFETs going with it or saving buying a expensive power transformer.

I am short the below parts for finishing some builds and was hoping to buy parts to complete them here on the forum.

12 KSC1845 transistors

8 IRFP140 Mosfets

I am hoping to get these items at normal cost but willing to pay for shipping! The mosfets aren’t as important to get than the transistors.

Any help is appreciated.

I’ve checked how it’s wired up, and it’s earth, live and neutral just like a modern plug. So seems safe.

Just wondering how I can plug it in to try it out.

Dan.

Got a ton of fake 2SK-117 of fleabay, but need a few good real ones!!

Lemme know if you have a few to sell - maybe around 8 - 12?....

Just curious as to the science behind this ... If you were to suspend your main speakers from the ceiling, using a heavy duty bungee cord set up, BUT keeping the speakers the same height off the floor, as if they had standard speaker floor spikes on them. So same height and placement, just not touching the floor by maybe one inch/....
What happens? Should it not help isolate some of the cabinet's vibrations to the floor and wall?

recently purchased new capacitors form one of the big supplies.
i bought 470uf 50v aluminum electrolytic caps.
i tested them to all be around 430uf.
the ones i am replacing are about 30yrs old and test around 460uf.
at 430uf the new ones are still within 20% spec, so do i use them being new and off by 40uf