Slightly off the wall one here but been reading a very interesting article from the mists of linear audio volume 3 by Steven van Raalte and comparing with the Bob Cordell vinyltrak article. In it he discussed an inverse resonance filter for dealing with the resonances that MM manufacturers build in to prop up the high end response, the end result usually being a bump in the response somewhere between 12 and 15 KHz then a 4th order roll off. Whilst this is
not a horrendous problem for us oldies who can't hear up there anyway it is predicted that this causes some unwanted time domain issues that the inverse filter addresses.

Now what would be nice is for there to not be any resonances at all in the audio band. Low inductance cartridges don't need the help so don't have the resonance. Therefore there is something about the design of the cantilever and/or the suspension that causes this. Once we know what it is then we stand a fighting chance of working out how to remove it. If it can be addressed then, with some changes to cartridge loading as discussed by both Cordell and van Raalte we can get a nice 1st order roll off to well above 20KHz and put the MM back on a level footing with MC models. Looking at this more deeply it appears this issue is one of those that was well known about in 1975 and many have forgotten.

So first step is to get a grip on the potential problem. Now I have 3 cartridge types I am interested in (as in own)
1. AT 150MLx 2K 450mH, 100-200pF recommended load
2. Ortofon super OM 1K 580mH 200-500pF recommended load
3. A&R x77 series (aka Garrott, aka Sumiko Pearl, AKA shelter 201 etc). 580 580mH

The last one is more of a 'project' as I have 4 cartridge bodies to perform evil experiments on and there are a wide range of replacement stylus types that will fit including the sapphire Jico SAS.

Now immediately I have run into some problems as both the Cordell and van Raalte cartridge models are over simplistic. Digging into this further shows the model is more complex and difficult to measure (Elliot). So we need to get empirical. More research shows that the best way to do this is to find a test record with square waves on and measure the response. Bother I don't have one of those, so £40 will have to go Ortofon's way as willing to bet CBS STR-112 costs $$$ these days. Once I have Jan's permission will pop in a diagram from the van Raalte article to show how the inverse filter cleans up the ringing on square waves. If I am right (unlikely but we all get lucky sometime) then you can record the output of the preamp and use audacity to mess around to find centre frequency and Q for the filter. When that is known we can see how much of a resonance is designed in.

Note: I am expecting to find that the ortofon and AT are not using too much in the way of mechanical cheating, but suspect the A&R does. Certainly both ortofon and AT have -3dB points at 30kHz which suggests the main cantilever resonance is way out the audio band.

Links. There are a couple of JAES papers that would help in this, but at $33 each I'll bumble around being empirical a bit longer.
https://linearaudio.net/sites/linearaudio.net/files/lte_vol3_1.pdf
Magnetic Phono Pickup Cartridges
http://www.kallhovde.com/advent/phono-pre-research.pdf

I would like to test what a modern class D amp can do. I would like to buy ready-made modules and plug in the recommended power supply. Can you recommend something worth buying? I am interested in a good hi-fi stereo, not a subwoofer driving 😉 It could be something Chinese if it plays good.

Hellppppppppp

Hi guys. Have a sound digital 12000.1 here that I just would like to confirm I have the right ID on these parts before buying. Need a 15v smd diode. Is this just a regular diode or anything special?
My local online supplier don't seem to stock any regular 15v SM Diodes....
Photos below. Thanks

I'd be interested in a transformer, a bad board etc. After troubleshooting my S1 i find the transformer is flakey. I lost half the balanced output and can get it back by messing with the transformer mechanically, rapping it etc.
Jim

Greetings, MY GORILLA 2400 watt Class D amplifier has a bad transistor upon INITIAL exam. Transistor on the way tomorrow SO... check things out. It APPEARS I am not the FIRST to repair this near SPOTLESS amplifier. It is so shiny it dont even have any DUST on it. SUPER CLEAN. I examined the board and its obvious there is a REPLACEMENT transistor in there. WELL its on the SAME side as the DAMAGED transistor so I am ASSuming these transistors are not holding hands and merry... I will attempt a replacement of the bad transistor and hope for no other bad aspects BUT.... worried this thing will self destruct yet again upon HARD USE. Only way to tell is... HARD USE so thats in the horizon IF I can get this thing to operate again. Myyyyyyy GORILLA!!!!

hey everyone!
Ive decided to build a new speaker.

Drivers will be:
18" woofer. Woofer choice not made!
Audax pr170mo or PHL 1120
Hivi Rt2Ha

Ala Geithain arrangement: https://www.kmraudio.com/geithain-rl901k-pair.php
The box will be about 180L.

Ill be upgrading this thread as i go!

So my question is that can i somehow remove filtering from satellite speakers? They sound very tinny. I opened control pod but i was surprised seeing a active preamp. Also i would love to add one RCA output from the bass knob if thats possible somehow.

For sale pair of Satori TW29RN-B - 4 ohm
Price 210euro with shipping inside EU

Anybody interested in these Beyma CP350Ti? They were my friend Matt's, she has a quad to sell. Make offer, asking 50/each plus shipping, orig retail was about 120. Like new condition. Lower 48 states please.

Evening Gents

Is it possible to have a FAST MTM MLTL speaker using two 6.5" woofers with a small fullranger and vary the crossover point depending on music played, say if using the MA 7.3, from 120 to 320 hz allowing one to optimize for the genre of music being played or does bsc have to be built in to the design thus determining physical dimensions resulting in only one crossover point that works?

Thanks,

Sheldon

SOLD SOLD SOLD SOLD

SOLD SOLD SOLD SOLD


Gently used NC502MP $200 obo+shipping and PP fee.

Hi all,

what test equipment is recommended for meusurements of speakers to tine tune the design (open baffle --> shape) and crossover design?
I already bought a mic (omnitronic mm-1c) with stand.
I want to do the measurements with my laptop, so I need an audio-interface for output (ideally cinch) to amp--> speakers and input for the mic.
Most audio interfaces with mic preamp seem to have only line (6.3 mm) in/ouputs but not cinch.
What is better: "Standalone" mic-preamp and very simple audio-interface with cinch, or an audio-interface like Steinberg ur12?
Are the outputs independant so that I can use them for the e.g. sweep output and record the mic simultaneously?

Hello to all, I have a Hughes & Kettner 25th Anniversary guitar amp that came stock with 6n15n-EB tubes and one has a crack in the glass and it still functions but I don't trust it. I bought the amp used from the original owner and it is like new and it has never been apart so it must've come this way from the factory. I understand that these are not EL84 tubes yet H&K says the amp has EL84's. I called H&K to get a replacement and they said to use any EL84 tubes. Terrible customer support lacking any details. They rarely answer email. The earlier versions of this amp both had EL84's in them. I don't know why they used these 6n15n-EB tubes instead of regular EL84's but they do brag about them in their advertisements as hand picked military top drawer tubes, and they do seem to sound pretty good. I would however like to try some EL84's like JJ Teslas to compare the sound but I'm not sure if standard ones can handle the 400V plate voltage that I've read this has. It seems that most standard EL84 tubes can only handle 300V max. I can't find any spec's on the 6n15n tubes to see if they are rated higher than 300V and I don't know what type EL84 tubes the earlier version amps came with. I'd like to know if I can go with standard EL84's or if I have to limit myself to the small amount of higher voltage ones available, or should I just stay with the 6N15N-EB type even though they seem to be difficult to find and maybe not as desirable as EL84's for guitar tone. Thanks for any input.

Hi guys.
I need help with the Arcam A70.
The amp runs very very hot. Bias is 250-300mV for both channels and does not tolerate adjustment.
There is no service manual for this model, but there is one for the A80, which according to some users is the same as the A70, but with a larger transformer.
What do you think the problem might be? I read that it could be the emitter resistors that are built into the SAP15N/P transistors.

scheme for A80:

I had a need for a 5V amplifier, and a quick search showed the easiest commonly available module is based upon the PAM8403, and cost about $0.50 per unit.

10 Pcs PAM8403 2X3W Mini Audio Class D Amplifier Board 2 5 5V Input US SHIP M323 | eBay

Having played with these for a few days now, I can safely say, if you only need a few watts, you will not find a better amplifier for under $1.00. The sound is very good, and the board layout is not terrible. However that is not what this thread is about, just a bit of back story.

After being very satisfied with these I looked into other Diodes inc PAM based amplifiers, and discovered the PAM8406 which is pin compatable, supports down to 2R loads at 5W/ch running 5V. That is all well and good, but you might be saying "I don't use any 2R speakers that will run well at 5W", and you would be correct. The real thing about this chip that caught my eye, was the "mode" selection that the PAM8403 does not have. This chip can be operated in Class AB mode!

After inspecting the layout for the $0.50 boards, I found the mode pin (listed as NC for PAM8403), is already tied to ground, so a simple chip swap will give a PAM8406 amp ready to run in Class AB. So that is what I did, and I can report that it is a fairly significant upgrade from the PAM8403, at the cost of a much lower efficiency.

Now, since this chip is such a simple layout, I thought maybe I can do better, which brings me to the real reason for this thread. I have done an initial layout for a PAM stamp, and would like some feedback. I based my layout on the Chinese board, but made several improvements.

1.) Increased input decoupling. Was already fairly good, but can always be better.
2.) Eliminated external 10kR resistor from input, instead relying on input impedence to form the input filter.
3.) Added ground plane everywhere for noise suppression and EMI
4.) Added ferrite bead filter on the output for EMI
5.) Cleaned up the input and output headers (IMO, this is a personal preference thing)

Please note in these photos, the signal input ground should connect to the ground planes surrounding it, I need to fix the copper there. The bottom of the board is a solid ground plane.

Would love to hear the opinion of those with more experience laying out boards, I basically have no clue what I am doing. I will try to get some high res pics of the Chinese board I started with for comparison tomorrow. I can post component values for the passives if anyone wants to know.

I have
2) Eminence Beta 10CX
2) D220Ti
2) completed crossovers
with a few weeks use.
$450 $425 $400 includes shipping within continental US. (ships from Northern California)

https://ampslab-spk.com/2021/04/25/osprey-br/
If you email him he will send build plans for the box.

pictures added below.

feel free to make an offer, especially if on the west coast where shipping would be cheaper.

​

Does anyone know of a mod, what parts would be needed or how you could convert a PAS3 to a PAS3x with tone controls that are out of the circcuit when centered? Or... possibly the instructions/schematic for adding a switch that would simply bypass the tone controls when not needed?

Thanks in advance.

Sold


Cardas CPBP pair rhodium over silver short copper post patented speaker binding post.

Never soldered to. Unused.

These have the short rhodium over silver plated posts.

Retail is $104 per set of 2.



S

SOLD

Alas, another project that will not happen.

Asking $40 $30 for the pair, including shipping to Continental USA

If you are contemplating building the Liionidas Open Baffle speakers, I have two crossover bare boards for super premium part mounting as designed by Ale.

Liionidas speaker link:

http://www.modelpromo.nl/audio-dandy/reviews/The Liiondias Open Baffle Speaker/The Liionidas Open Baffle speaker.pdf

Each board is 198 x 120mm.

It calls out for

Jantzen C-Coil Torroidal Inductors
Mundorf M-Cap Evo-Oil Cap
Mundorf M-Resist Supreme 20W Resistors

I will include for the new owner my correspondence with Ale about the crossovers and boards.

Hi friends
I‘m tempted to bid on a sony sh-155 headshell, but didn‘t get no answer to the question: can it be used on SME and/or SME-compatible tonearms?
I meant: is the (bajonet-?) lock the same, and is the length ok to get a cartridge adjusted properly?

Thank you!
David

And they were hand treated with de-oxit .... 😡😡😡

https://www.russandrews.com/internal-superfuses-/

I’ve stayed long on this and built it many years ago and I must tell it has served me well and still operates as expected. This amp is 12W class A - single ended, 10k input impedence m also it’s Power JFETs on the output.

Then a little building details it’s has 5U chassis
with Dual mono power supply (2x 300VA transformers, and 68000uF capacitance per channel in CLC configuration. Includes Soft start circuit and it’s built on High quality parts.

I’m interested in selling it for $1200

Hi All,

I've been inactive in the DIY speaker world (and on this forum!) for a few years but time and opportunity has finally come to finish some speakers that have been half finished in bits in storage for years for lack of time, working space and money... 🙂

Years ago (since 2003) I used a Desktop Windows XP PC with a Sound Blaster Audigy 2 ZS as my measurement card - one of the few prosumer cards in the early 2000's that supported true 24 bit 192Khz recording and playback without re-sampling and had very good analogue performance, and I used it extensively for speaker / crossover measurement with various software including most recently ARTA.

Unfortunately in the last year that PC has gone belly up, and as the card was an original 32 bit PCI card that most PC's today won't support I can't really put it in anything else, even if I had another desktop PC to put it in...

Besides, it was very inconvenient using a large, noisy desktop PC for speaker measurements!

Nowadays I use a Windows 7 Laptop but it only has a single shared mic/speaker socket, and even if it had both I'm sure the quality would be dreadful compared to my old card anyway and inadequate for precise speaker/crossover measurement.

So I'm in the market for a USB sound card, and my requirements are:

1) Preferably under £100, in the UK.

2) Full duplex, naturally.

3) True 192Khz 24 bit without any re-sampling or other post processing, and the flat frequency response and low distortion/noise floor that you would expect of a good quality 192/24 card.

4) Must work well with ARTA.

5) Inputs that support both XLR with phantom power for the measurement microphone, and line level input for direct connection to crossovers, making impedance measurements etc.

6) Inputs must be fully independent - eg independent selection of XLR or Line, independent gain control etc.

This is important to be able to make proper use of dual channel mode in ARTA - typically you would connect the measurement microphone to Left in XLR mode with phantom power, and connect the right input in line level mode (possibly with a suitable L-Pad) to the input terminals of the speaker to cancel out any response errors in the amplifier, random delay variations in the sound card that might affect phase measurement etc.

I did a quick 10 minute browse tonight and came across one promising candidate at about half the maximum I'm prepared to spend, the Behringer U-PHORIA UMC202HD USB Audio Interface:


Behringer U-PHORIA UMC202HD USB Audio Interface | DV247


It seems to meet all my requirements above, and seems almost too good to be true for the price. Is it ? (Or have things just moved on a long way in the 10 years since I last looked at USB sound cards!)

The only thing it seems to be missing that would be good is a "high impedance" mode for the inputs, which would be useful for more accurate measurement of crossover outputs without loading them down, and also be necessary for impedance measurements.

I'm assuming it will have an input impedance of about 600 ohms or so in line level mode ?

Another interface that does have a high impedance mode for one of its inputs and thus would be better for impedance measurements and direct crossover measurements is the Steinberg UR-22 MkII:

Steinberg UR-22 MkII | DV247

It's also pretty similar in other regards, however it's about twice the price.

Am I going to run into problems with impedance and component measurements without a high impedance mode ?

I don't have access to an RLC bridge anymore so I would quite like to be able to measure crossover coils and caps (mainly coils, as my multimeter can do caps) using ARTA as well using an RL / RC test configuration.

Any thoughts and an opinions of these two boxes, or recommendations of other ones to check out in my price range ?

On a related note - in the house I currently live in I won't be making most of the measurements in the living room (not enough reflection free window time) and whilst my laptop and a USB interface are far more portable than my old system for measurements I still have the issue of the amplifier.

I now only have one amplifier and it is well and truly fixed in place in the main AV cabinet, getting it out to take to another room to do speaker measurements would be a major PITA.

So it occurs to me that a small, portable amplifier that I can use with the USB audio interface purely for the purpose of driving a single speaker to take a frequency response measurement would be extremely handy, if not essential.

It doesn't have to be fancy - it doesn't really need anything more than a volume control, doesn't need to be stereo, doesn't need tone controls, lights etc. What it does need is very flat frequency response, low output impedance and an output of about 10 watts. Something that is not much bigger than the USB audio interface would be great, as together with the laptop and USB audio interface it would make it possible for me to measure just about anywhere including the holy grail - outdoors!

Is anybody using a small portable amplifier for measurement tasks and have a recommendation ?

Hi
I am looking for a small class AB or B Amplifier with around 50-100W with an onboard PSU where I only need to connect the transformer and do not need a separate PSU. The idea is to convert my nice small studio monitors from passive to active. Each Speaker would have his own mono Amp, and the Filtering will (in this case) be passive. I tried with class D modules but I miss a bit the musicality. Class G would also be OK. If the PCB artwork has already be done, even better as I am not the master PCB designer.
Any suggestions would be warmly welcomed.
Best regards
Christoph

Has anyone done this https://www.firstwatt.com/pdf/art_plh.pdf to one of JLH's to be had on ebay .
To be clear I mean to implemented the mod, but stay with bipolar parts ?
Cheers
Lee

A long time a go a friend made a comment about the Dynaco PAS4 that the triodes on a ECC83 was parallelled. He did not understand why, i did neither
at the time. Now i know better.
The issue has been a thorn in my mind, especially as none of these amps
ever came to sweden, thus we had no experience of the amp and could
not say if it was good or bad.
A few years ago in a discussion with roy mottram a decision was to
make a few boards, i eagerly bought one.
Now time has come to realize this amp.

See Dynaco PAS4 klon where the build process is documented.
( it is a test-features amp, not all features will be implemented at this time)
Anyone with experience of a read PAS4 is welcome with experience of
a real pas4. Everyone else is of course welcome with comments.
One detail has interested me : the loop output.

The loop is a way to loop the signal thru an external tonecontrol box or
equalizer , where the loop itself is enabled with a switch. Thus for anyone
that don't want tonecontrol will not connect anything here. Others can
buy or build a tonecontrol box, connect it and use it at will. The nice with
this is that one can always disconnect the tonecontrol with a switch when
it is not wanted.

I have populated the board, done some repairs and slightly changed the
circuit by a few LED used to bias instead of the original somewhat
"kludgy" way of obtaining a small negative voltage.

Within a month i hope to have the box ready for use. I'll update the above
link as build progresses.

So I was taking my daily walk a few days ago and stumbled upon some discarded Bang and Olufsen Beolab 6000 speakers.

One had been kicked over and lightly urinated on by a local fox and considering where I live London I was surprised this was the limit of neighbourhood interference. Rule of thumb around here is, if its not bolted down its stripped for parts and then what’s left is set alight, I suspect the rain that day slowed proceedings.





It seems they were discarded as they has suffered which now I understand to be a common problem of cracking rubber speaker surrounds.



As they were wet, dirty and smelling of fox urine I decided to strip them down, dry out the damp electronics and then wash the contaminated parts. Turns out the scent of a fox is very tricky to get rid of, something I hadn't anticipated.
Once dried with a hair dryer it was time to move onto testing them.







When launched in 1992 these speakers retailed for $2500 which is an incredible amount of money considering, although they seem to be well made using a cast aluminium chassis which doubles as a heatsink, fibre reinforced composite for the driver and tweeter housing and branded components for example Hitachi wires and Elna caps.

Both speakers are working so I ordered some replacement rubber speaker surrounds from Audiofriends in the Netherlands, the kit includes 4x surrounds, glue and fitting instructions for £24 including delivery, very reasonable. These replacement rubber surrounds apparently also add a little extra bass, I’m not sure how though.

I then proceeded to remove the old surrounds and adhesive in preparation.





Having used Beolab 8000’s in the past I’m fully prepared to be underwhelmed by these speakers, however in London space is a premium and these speakers would would work well as bedroom units given the small footprint and active design.

I have a Bluetooth 5.0 module lying around and noticed that it would fit perfectly attached to the back of the MOSFET unit, the screws are correctly spaced and the threads are the right diameter with some spacers to move the board off the back of the MOSFET unit and with longer screws to accommodate the spacer it should fit well (could the switching frequency of the mosfets effect Bluetooth?..

There’s a few challenges to overcome, one will be finding a 12v - 24v DC supply from the board, ideally I’d like to fit the module with minimal hackery so as to keep the speakers looking stock externally.



These Bluetooth modules have an auto sensing line-in input meaning the aux input on the bottom of the unit can be retained keeping inline with my minimal hacking ethos.

The second somewhat easier challenge is routing the second channel of the Bluetooth DAC module to the other speaker whilst also retaining the aux input. As I understand it these speakers can be daisy chained using the B&O power link connector (a proprietary DIN based connection) but this only works when a B&O preamp with a power link connection is used. On the bottom of each speaker is a toggle switch which allows setting to left or right depending on the positioning of the speaker within the room.

When using something other than a B&O source with Powerlink, each speaker would then have to be sent one channel each using an single channel RCA, as each speaker has a a single RCA aux input. For example the left speaker is fed a the Left channel using an RCA cable and the right speaker is fed the Right channel using an RCA cable.

My assumption is that it would be tricky to utilise the Powerlink connection as my interconnect whilst still keeping it working as a powerlink connection as it’s proprietary. As I don’t have any B&O sources and don’t intend to I guess I can remove the connections on the internal amp side of it and just use it as a DIN based interconnect assuming I make modifications to the other speaker.

My question is, what would be maximum cable run I could use to send that line level signal from the tiny Bluetooth DAC module to the other speaker? I presume a few meters will be fine.

Whilst looking inside the speakers I noticed a severe lack of damping material. My knowledge on this area is limited but I suspect due to the small internal volume of these speakers (3 litres) any extra damping would reduce the internal volume too much, hampering the already limited bass performance. Would adding something like thin layers of basotect (cut up magic eraser) instead of the grey foam already in there improve things at all. I’m not sure what I’m looking to improve to be honest, maybe reduce any resonance of the aluminium housing?



Lastly I’ve ordered some adhesive backed foam tape to replace the horrible disintegrated stuff in there. Apparently a known fault with these speakers and beolab 8000’s is something coined as foam rot.

I have recently purchased a quad 33 and 303 in original condition.
The only problem is that i am not getting right channel sound.
I have ruled out cabling issues.
I am connecting to tape replay using an rca cable to DIN which i connect to my laptop.
I have tried all stereo left and right buttons. but simply not getting audio from the right channel on the 303. The speakers work.
I am going to confirm soon to rule out the 33 by measuring the output from the 4 pin DIN output cable.
I've opened up the 303 and the only obvious issue i can see visually is the C104 cap on the left driver is blown (as in the top casing of the capacitor is gone and i see the yellow internals) but the left channel works. the right channel driver components look fine. everything else also looks fine visually

Please could you provide a fault finding instruction to identify the fault causing the right channel not to work?

any help would be appreciated

Hello,

I was hoping for some advice as I may be above my head in my enclosure knowledge.

I have some AM6200/95 Mid/High compression horns which I like the sound of, and I sat them on top of some existing JBL bass units I have.

These are the JBL 4637 - not to be confused with the much more expensive 4367
https://usermanual.wiki/JBL/4637.1891637758

These are made up of a 2035HPL driver in a C4507 cabinet - cabinet info here:
https://jblpro.com/en/products/4507-4508-4518-4550bka-4560bka

The bass response sounds a little sloppy now compared to the mid/highs on top, which are a much higher grade speaker from JBL.

My question is because I don't understand enclosures enough to know if this is a crazy idea, but I can easily buy some JBL 2216nd which I know are great models as per the M2 and funnily enough a variant is on the 4367.

I think the 2035HPL can be swapped for a 2226H without issue, and I saw mention of using a 2216nd instead of a 2226H in many threads which got me thinking.

I assume I would get a much better response immediately than the 2035HPL, but I don't know if my enclosures can 'handle' it.

The enclosure specs as per the link:
Lowest Usable Frequency - 40 Hz

Q
500Hz - 4
800Hz - 8

140L - 5 cu ft

546 x 775 x 448 mm

Not knowing about enclosure design I wondered if anyone could tell me if this was an insane idea.

Speakers would be for general purpose stereo use, movies and music.

Thanks for any help!

Need help replacing these components. Marked on schematic as TH103-2 and listed as thermistors. However they measure as diodes?

In the thread (now closed) "The battle of the DACs, comparison of sound quality between some DACs" there was some discussion (or debating) about the impact of close-in phase noise on DAC output.
One way to measure the phase noise is to look at the noise skirts in FFT spectrum as JosephK did here: https://www.diyaudio.com/community/...jitter-crystal-oscillator.261651/post-6710439. This requires a very small bin size. I decided to make similar measurements with REW albeit the FFT size in REW is limited to 4M. But anybody with REW, DAC and ADC can repeat these measurements.
I used my own boards for the measurement:

• AK4490 DAC
• ES9822PRO ADC
• USBI2S bridge

The master clock was on ADC board and DAC used the same clock.

First 11.025k sine of -1.5dBFS at 44k1. This uses 22.5792MHz ECS-2520MVLC clock having phase noise in datasheet as -89dBc/Hz @10hz (https://www.mouser.fi/datasheet/2/122/ECS_2520MVLC-1903379.pdf).


Note the horizontal scale (+/-10Hz). Not bad for a $1 clock.

Next up 12k sine of -1.5dBFS @48k. This uses a 24.576MHz NZ2520SDA clock with presumably lower close-in phase noise.


Clearly better but whether or not audibly better is another story.

Besides clock there are other factors that affect phase noise. One is Vref. In my AK4490 DAC Vref is fed by LT3042 regulator (separate L/R).
Here is the same measurement as above but with slightly altered Vref implementation.


Clearly much worse and a much bigger impact than clocks.
The only difference between graphs 2 and 3 was that Cset capacitor of LT3042 was changed from 22uF/15V tantalum polymer to 22uF/25V X5R. The result is understandable as Cset affects the 1/f noise of LT3042. Input and output capacitors of LT3042 are not critical for Vref phase noise.

So, my 7yr old daughter has been blasting some old CDs we had in the basement, and I have meant to build her some sort of audio system but life, work, etc etc... When I exclaimed at how crappy it was, she got upset that I was threatening her precious lil music box, so I had to explain to her WHY it was so bad and that I wanted to do a project together. That got her interest piqued! I did look into off the shelf units, but at $3-600+ for anything halfway decent, I figured we can learn and build a project together for that and have a much better system in the end.

I was initially planning to build the PE blast box into an armored case she could carry around, but reviews were not kind. Then I remembered the armored flight case I had lying around in my garage for years. It's about 15"w x 20"t and each half is 4.5" deep. The handle takes up a little extra volume on one side, but I can balance that out. With that and other components taking up space internally, it'll be about 0.5cuft which is perfect for an 8" sub.

I wanted to keep it simple, and I've been thinking about full range for a while, but there's obviously no way I could stick a voigt pipe in there. I found the Dayton Epique 7" extended range sub which seemed perfect. If I put the electronics outside the box, it's just big enough for a ported box with that driver and a low response tweeter, but the availability went from "in stock any day" to "in stock in July." Her birthday is May 20. Then I started finding and learning about open baffle which would have been perfect. I'll not go into details here, but it would have been really cool to have dual long throw 12s bumping on either side with the magnets hanging out the back, not to mention the ease of building it. I had an entire plan worked out, but every component was like, "well that's a little more than I wanted to spend, but for my daughter..." until I decided to add up what I had planned and came to a whopping $1500!!! My budget was supposed to be about $500 max.

So then I decided to go back to the drawing board for the umpteen millionth iteration, but this time with a strict budget in mind, and no complicated modification of the box (bigger than 8" driver would require the handle to be worked around or removed). I found what looks like a very decent sub-mid range driver capable of well into 1500hz in the $50 Dayton 8" DVC sub. Handles 80W with the same on the 1,1/8" aluminum dome tweeter at 4ohms (with built in grate/guard), perfect for a US Acoustics Lisa car audio amp which has really nice built in crossovers that go remarkably high for a car amp (3.5khz). Along with a 350W meanwell supply and a lithium car battery, this should be quite flexible in use, from home to car to battery powered at the park, etc.

All I want is decent sound with some nice thump with bluetooth 5.0 or headphone input. No volume knobs, no controls, nothing complicated, based on common 12V car audio. Just set it so you can connect to it and use the source for volume control. I think this will work nicely. Here's the component list so far, should be in this week in time for her birthday on the 20th:

• Dayton Audio bluetooth 5.0 module (small amp built in, but I'm only interested in the RCA output). I plan to install and wire this inside of the amp leaving it's inputs open.
• Dayton 8" DVC sub
• Dayton 1.125" reference aluminum dome tweeter
• US Acoustics "Lisa" 200W A/B car amp crossed over at 1500hz.
• Meanwell 15V 350W power supply, adjusted down to 14.6V
• Valence U1-12RT battery, 12.8V 40AH with continuous discharge of 30A, 80A peak. These come from medical carts replaced every year regardless of use and often not much at that for just $170 on ebay.
• A 2F power cap with volt meter. I know these are passé for car audio when you really just need a bigger alternator, but the meanwell doesn't have very big power caps in it, and it may not be able to keep up with peak power drains on heavy bass which could cause the volume to waver a bit and/or stress out the supply, so this is actually a very good use for these otherwise useless car audio pieces. Bonus with the volt meter to display battery voltage.
• And, instead of wiring in a dedicated 3.5mm jack, I figured, with the RCA inputs exposed and the BT module tucked away inside the amp, it would be better to have a 3.5mm to RCA cable anyway that can simply be tucked away when not in use.

Then we just need to cut material to complete the boxes inside. To keep enough space inside and to simplify the build without complicated structures inside, I may put the electronics outside the back of the case (woofer has to be on the bottom anyway leaving plenty of real estate above the tweeter). That way it can still be played with it closed up if need be, plus it matches the car sub aesthetic. It also frees up nearly 0.7cuft which is enough to port it to really get some low end thump out of it.

Are there sonic differences between them. I have 45's, 2a3's but no 300 b's. Am I missing something. Starting another build and need to make a decision.

Anyone experimented with flat panel actuator driven speakers. Saw YouTube video tech information "world's best speaker? Integer by the concept and of course cheap me price. Cheap $20 40 watt actuators or excitors are adhered to poly styrene ceiling panels at 2/5 3/5 ratio o counter resonance peaks. Sound like a very cheap fun audio challenge to try. Other material like cardboard aluminum balsa wood you name it are fair game. Challenge some of you to try different media. Can't go wrong with $40 both actuators and practically throw out material to make. Give me some feed back on any results or ideas. I will order a couple to just have fun with. Michael

SOLD

Asking $35 for the lot including Ground CONUS shipping

Selling as a lot, maybe you will have a need for a few of them:

Antek AS-0507, shortened leads 0-7, 0-7 vac, 50 VA

Hammond 166G9, short leads, 9 VCT 500mA

Pair of Hammond 166L10, one new in box, one with shortened leads, 10 VCT 2A

Triad C-14x 6H, 200mA choke added to lot

I have not been able to find any information, either online or in textbooks regarding the resistance looking into the collector of a Sziklai pair; I have assumed that it is, to a reasonable approximation, neglecting early effect, the product of the two transistors’ betas multiplied by the (degeneration) resistance in the emitter circuit, but can’t find any confirmation of this. The reason I am interested in this is that I wish to put a riaa network directly after a Sziklai pair. Many thanks.

OK, here's a totally crazy OT question . . . which I presume won't work, but I'll ask anyway.

Someone on another forum recently posted a link to an old thread here about cheap output transformers. I had seen this before but it's been years. Anyway, in one post someone asked about using a PP OT in a SE amp.

One response was "In a PP application, the tube bias current flows through the primary winding from the center tap to the ends, which cancels out any magnetic flux in the core due to this DC current. In an SE application, this DC current flows from one end of the primary to the other, which will saturate the core resulting in poor performance. Manufacturers get around this by introducing an air gap in the core."

This made me wonder . . . if current flowing in only one direction through the primary of a SE OT is what creates the core saturation problem, would it possible to use a PP OT for SE with the B+ connected "in reverse"?

So, B+ to the ends of the primary winding and have the center of the winding connected to the plate of the tube. Since the current would not all be flowing in the same direction, would this cancel the magnetic flux in the core and make the transformer usable for SE operation without the need for an air gap?

Hello everyone. I hope this is the right place to post this. I recently obtained a tube amplifier from an estate and I don't know anything about it. It doesn't appear to be a commercial product or a kit. Has anyone seen an amplifier like this?

I'm looking for information on a couple obscure vintage Japanese McAudi 2520/990 opamps. Does anyone have any information from these? There is basically no information online, but what I pieced together is that it's either a API 2520 clone or Jensen 990 clone. Possibly to have been used in a Sony MXP recording console I'm guessing or standalone microphone preamps. I have no idea what the voltage is for them. Is there any way to find it if this is 16v or 24v?

I do have a ICE 1200as2 power amplifier and asking myself wether it would make any difference for sq driving it by a se-pre vs balanced pre. Cable-length will be less than 1 meters between the 2.
Do any of you have any experience or thoughts on this?

trying to figure out enclosure size reports shows it hits 20 hz by many users---

https://www.amazon.in/Rockford-Fosgate-Prime-Subwoofer-R1-S412/dp/B001P804A2-specs pdf attached please download

or you can search rockford r1s412 in amazon

i just need 20 hz at good db level subwoofer in cheapest price ported or ......

trying to design in winisd








i would prefer a enclosure around 70-90 litres but not getting proper results in winisd

i dont like 70 hz bass boom boom type only 20 hz to 40 hz what can be felt only

-----please help me enclosure size and aeroport size length

Hi all Sonab TT owners.
I have just bought a Sonab 85S and am seeking advice on what cartridges have been found to work well with it. Willing to spend some $s, but nothing crazy expensive.

what are you running?

cheers

Doug

Hello, would there be a way to check if the 6c33 valve is in perfect condition since there is no tube tester

Even though my Grand Heil MEH project is still not finished, I just had to buy the GRS PT6816-8 planar drivers since they could be a base of a more "living room friendly" MEH / Synergy with a single or maximum two mid/bass drivers. My thoughts on the design:

1) The woofer. While playing around in Hornresp, I have no problem with the upper end of the mid driver(s). What I cannot really simulate is the low end response. I discovered the LaVoce WSF081.82-8, which seems to be a suitable driver for the task. I am simulating the worst case port distance and up to 10" sized driver could be used. I am really lost here and I do not know what should the ideal parameters be for a two way MEH woofer. The crossover will be DSP and ideally, I would like the horns to be able to play on their own, they would be helped by a mono subwoofer if needed, sort of a 2.1 system.

2) Coverage angles. The planar driver will beam vertically - that is common knowledge - but from which frequency and how severe is that? That would dictate the vertical coverage. Other projects using planar drivers on horns choose usually 30 - 40 degrees, and 30 degrees seems to work fine on my AMT based project. When listening, I do not really move vertically, so narrow vertical dispersion would not be a problem. Horizontally, I see typically something between 60 and 90 degrees, with the preference closer to 90 degrees. A 80 H x 30 V pattern should work fine.

3) Secondary flare - yes or no. Reading of other builders' experience gives me the impression that a secondary flare is not really necessary. Not having one makes the build easier. Would it make any sense to make a secondary expansion in one direction only? What would then be the preference - dual expansion horizontal or vertical and why? I am considering if large radius a la onni's compact Synergy would be a better option - at least visually it looks good, athough I have no issue with the classical bwaslo-spreadsheed-designed style look.

4) Size. I would be glad if the resulting box could be about the size of a Bose 901 cabinet, SPL Runt outer dimensions being the absolute limit. I see that the Hornresp record I posted is quite larger than that.

Any input on the topic will be welcome as this project is in a very early stage and as usual with my other projects, it will take quite a long time before it will materialize🙂

I'm looking to build a TMW setup and am considering biamping it between the MT and W for flexibility and giggles (not interested in active crossover). MT would just be a normal crossover, but my question is, do I need to make any special consideration on the high-pass circuit for the MT and the low-pass for the W with a full range signal to both circuits?

My initial thought was that, in a full range, the signal gets 'divided' up between the M, W, and T, so every part of the signal has a place to go. If I were to biamp it and send a full range signal to both the W and MT circuits, the low end on the MT wouldn't have a dedicated W to handle the low end of the signal like it would in a MWT. Would I need to beef up my components to handle what would otherwise be the 'W' part of the signal since it doesn't actually have a W to handle that part of the incoming signal?

Got this Arcam AVR350 on the bench, which has problems with speaker relays (the blue ones incircled in red).
I can't find a service manual for this unit, and as I need to remove several other boards with tons of wires to get access, I would like to have the manual in order to get it correct assembled again.....
Anyone here able to provide the manual or guide me??
Thanks in advance 🙂

[SOLD]

For sale: Allo USBridge Signature with case

The Aluminum case has back plate For DigOne Sig upgrade.

Include 32 GB micro SD card with Moode Player installed.

Good Condition.

Ask $190, free shipping to lower 48 states,

I seem to have an intermittent bad ground in my mic. Any clue how to open the darn thing? I took the three tiny screws out but to no avail.

Greetings,

I have a pair of Altec Lansing Bias 550's. To make a long story short, I've not been able to satisfactorily sell them, and like an aging Great Dane, they are too big to keep in our new home.

So, I was thinking of repurposing them into something more wall-mount/bookshelf sized. Any recommendations for how to proceed, or is this a totally infeasible undertaking?

Thanks.

Im trying to replicate the controls on this speaker.Not even sure what such a setup is called. Whats the technical term for it.
Is there a schematic somewhere that would give me an idea as to how something like this works ?.
If I could get the technical term for what such a setup is I could probably have better luck looking for info.
Sorry for the Noob question.
Have been able to locate some old 15 inch paper cone philips speakers. Want to use this kind of cross over.

https://www.hifispeaker.wiki/item/a...v01k3uBjnFSTPLMVijRTKmbOVZNKwrW_Uf3IOQHKRJ0Yw

Hi,

Quick question:

From what I understand, the First Watt clone power amplifiers require a bipolar supply of +/-24. Is there any tolerance for this, what would I need to take into account if I used a 2 x 19v transformer that would give a couple of volts over the recommended supply?

Thanks

Hello,

I'm looking for schematics / service data for dBTechnologies DVA T12 amplifier module. It stays in protect mode and doesn't want to switch on main PSU.
One green LED on the PRE_MAN_BOARD is flashing five times, pause, five times and so on. On the PSU board only the LED2 is on (PSU auxiliary 5V is present).

Thank you very much!

Best regards,
Boris.

Hi, I've got an issue with some new to me speakers that I'm hoping I can get help with here.

I was recently gifted an amplifier and a pair of speakers which has been sitting around for at least 10 years.

The amplifier that I was gifted wasn't anything special and had some issues so I got rid of it. I then bought a used Denon UPA-F88 as a replacement, it's small size perfect for the location I want to place it.

The speakers are Wharfedale KH-2110 towers. From the info I've been able to find on them, which isn't much, they're marketed as an home audio/theater and karaoke speaker.

When hooked up to the Denon amp the speakers sound muddy. This is a similar sound to the old amp, but that had more issues as well, the Denon amp sounds much better in general. Curious as to why the speakers sound so muddy I tested each speaker. These are bi-wire speakers and the bridges are installed fine. I removed the bridges to test the high and low drivers separately. What I found was that the low drivers, the midrange and bass sound great, the volume goes as high as I need it to, and doesn't have any issues from what I can tell. The high driver, the tweeter, sounds terrible. It makes sounds, but seems like its muffled, and the volume, no matter how high I turned up the amp doesn't get loud at all.

I think that's what must make the speaker sound muddy, the complete lack of highs, and just mid to low end playing at a higher volume.

Then, I pulled all the speakers and tested them. The nominal impedance is suppose to be 4 ohms, though I'm not sure what that means when testing the speakers directly.

All the midranges and woofers tested pretty much right at 4 ohm. The tweeters though both tested at 4.8 ohm.

I then hooked up the tweeters directly to the amp, turning the bass down and the treble up, with the volume at 0 to start with.
Both tweeters played music, but as I slowly raised the volume, one of them sounded like it was muffled.
The volume on both tweeters though was relatively low when compared to hooking up a midrange or woofer for comparison.

This has been the case too when the tweeters are installed in the speaker box. The tweeter volume relative to the midranges and woofers are very low. So much so, that even if the amp is turned up all the way the tweeters volume isn't room filling. Where the midrange and woofer volume even with the amp turn up only slightly can fill the room with sound.

Based on this, it seems to me that both the tweeters and crossovers might be bad. I'd say the tweeters for sure, but I'm not sure about the crossovers.

In order to test the crossovers I purchased some cheap 4 ohm tweeters to hook up so see if they play fine. They too played when installed played at a very low volume, but when played directly from the amp played at a normal volume. Based on this it seems to me that the crossovers are bad too.

So, it seems that I'll be needed new tweeters and new crossovers.

My question to you is what is the best way to go about this? Should I try to get the tweeters and crossovers repaired? Or buy replacement tweeters and crossovers? Or any other suggestions?

Wharfedale doesn't sell replacement parts for these speakers anymore so I can't get new stock from them.

Any advice or comment is greatly appreciated, thanks!

I'm new to designing with tubes, and have just built and tested my first project, a P-P amplifier using a pair of 2E26 beam power tubes. The datasheet indicates that a class AB2 audio amplifier can achieve 40W or 50W output depending on the anode supply voltage, and output transformer impedance. I chose the more conservative 40W.

Although the amplifier works and sounds nice to my ears, I am having trouble understanding why I can't achieve more than 32W output before there is clipping. When I probe both the output voltage and the cathode current, you can see from the scope screenshots that the output is clipping, but the current into the transformer still appears sinusoidal.

This looks like saturation in the output transformer, no? Initially I was using an Antek 40W toroid with 6.6K primary, so I figured I would try an Edcor 50W with the same winding ratios, and hopefully the problem would go away. The new transformer made no difference!

After studying the signals for a while, I noticed the output signal was asymmetrical. I figured this was causing a DC current to run through the primary. The lopsided waveform turned out to be distortion from the pentode amplifier, which I replaced with a different circuit using a current source for bias (not shown in attached schematic). Although there is now much less distortion (2nd harmonic 40db down), the clipping remains.

I've adjusted the bias so there is 20mA idle current, as specified in the datasheet.

I'm testing the amplifier using a resistor load, and verified that its value is 8 Ohms. I'm measuring the RMS voltage on the output with a Fluke meter.

I'm thinking there might be something obvious that I'm missing. Any ideas?

2E26 Datasheet

Take a look at the Simplified schematic.
There is nothing strange, but the difference is the CFP output.

The distortion is low when we finetune the quiescent current.
THD 0.000058% at 1 Watt in 8 Ohm.

The circuit uses only transistors that are possible to buy.

Power Supply should be a transformer 2x22VAC.
Each winding rectified for each channel.

I'm thinking about adding an Oscilloscope to my bench as I dive deeper into building audio amplifier and power supplies. I have no idea how much I'll be using it. Amazon offers a scope with built in signal generator for under $200. Specs below. Would this serve a home hobbiest well? How about these little handheld scopes that sell for around $50...Waste of money? Will the built in signal generator be enough or should I add a signal generator to the cart?

Function​

* Analog band width: 100MHz * 2

* Number of channels：2 channels

* Maximum real time sampling rate: 1GSa/s

* Vertical sensitivity: 50 mV/div ~ 500 V/div

* Horizontal time base range: 50S/div ~ 10nS/div

* Maximum test voltage: 40 V (1X probe), 400 V (10X probe)

* Storage depth: 240Kbit

* Input resistance: 1MΩ

* ADC precision: 8bits

* Coupling mode: AC/DC

* Trigger mode: Single, Normal, Auto

* Trigger edge: Rising edge/Falling edge

* External trigger voltage 0 – 40 V

* Extension ports：USB picture export

https://www.amazon.com/Oscilloscope...e&qid=1646224765&sprefix=oscill,aps,88&sr=8-6

Electronics Illustrated, 1971, May, has two Dolby articles. One about the man and his life. The other about Dolby A and B processors which had just become available.
https://worldradiohistory.com/Electronics _Illustrated_Master_Page.htm
https://worldradiohistory.com/Archive-Electronics-Illustrated/Electronics-Illustrated-1971-05.pdf

The schematic of a Dolby B circuit has one error for sure (1000uFd 1% has to be 1000uuFd 1%), and maybe others.

BTW: Art Margolis was a very regular byline in EI and in bookstores, but Sylvia Margolis (I assume wife or other family) only seems to have two credits.

A few years back I heard the JBL 4367 back-to-back with a bunch of great Revel speakers. I liked the 4367 a lot.



The JBL waveguide is very asymmetric; much more so than the JBL M2. Both speakers use very similar components, IIRC the tweeter is identical. (JBL D2430K)

Hi Solid State-
Starting to search for parts to assemble a 24ch amplifier.

I'm not an EE but I've worked with class D boards on other projects, and made a few PCB for my LED projects.

I was hoping to either find and upgrade or build my own like the attached TDA7377 board: low BOM count, mostly thru hole parts. Use +-DC.

I'm a pretty good scavenger/bargain hunter so I have the drivers, DSP box, a 24x9x2" heavy heatsink, and Meanwell SMPS in 24v and 48v x 700W that have been getting dusty on my shelves.

All that said, here's what i'm after:
-Your favorite solid state amplifier chip for a low power build?
and
-Are there issues with arranging parts in parallel on the same power supply? for example - I had to set Master/Slave on tpa3118 boards to use them in parallel on a single power supply.

Just feeling things out. Any tips/ideas are appreciated. Thanks.

I'm sorry this is a bit of a repost. But I"m really hoping to get a few fresh eyes on this question.
I have here a Peerless poly cone 6.5 mid driver. The vendor assures me this bead of tacky sealant is added by the manufacturer to dampen edge resonance on Peerless's poly coned drivers. Legit? It is evidently hand applied. I wonder a bit at the likelihood of Peerless opting to hand apply this remedy in production of a 50USD mid woofer. Anyone at all out there that can verify this is the case?

I have a Tube SE phono amp I bought that I have been using. It has adjustable gain buttons on the front of it and with the high output MC Denon cart i have I noticed I needed to run it near the bottom of the range to match the volume of my DAC. (PS Audio Directstream). So I got to thinking that instead of running the 12 AX7 that it came with I would try out a 12AU7 and maybe the reduced gain would put me in the middle of my adjustability. So I swap the 12AX7s out with an NOS pair of Mullard 12AU7s. expecting to have to turn the gain up on the amp to get back in the neighborhood of where I was at. WRONG... Its the same damn volume it was with the 12AX7s. How can I go from a gain of 100 to a gain of 20 without any reduction in volume? Is it the secondary half of the hybrid circuit that is compensating for it? And I am now running my output transistors on the phono amp harder? I am confused. it sounds less "rushed" with these tubes. I kind of like it actually. The immediacy of the sound seems lessened. Hard to describe what I mean. But I am curious why its the same volume. with a 80% reduction in gain.

FTC Seeks Public Comment on Amplifier Rule Amendments to Make Testing Methods More Useful to Consumers

Text of the Notice of Proposed Rulemaking Regarding the Amplifier Rule

"Rated power shall be obtainable at all frequencies within the rated power band of 20
Hz to 20 kHz without exceeding 0.1% of total harmonic distortion after input signals at said
frequencies have been continuously applied at full rated power for not less than five (5) minutes
at the amplifier's auxiliary input, or if not provided, at the phono input."

Continuous rated power for 5 minutes is going to be difficult for many audio amplifiers.
Full power at 20KHz may be useful for testing a smoke detector.

Hello all...

I just purchased this amplifier from Alie Express (see link below).

https://www.aliexpress.com/item/3256801663270859.html?spm=a2g0o.order_list.0.0.25281802vqUYVO

In the specifications, it states that this amplifier goes into standby mode after 20 minutes or so. But the specifications also state that it can be changed to NOT go into standby mode, and just remain on all the time (unless you turn the amp off).

What do you do (instructions) on how to stop this amplifier from going into standby mode? I like to keep my amps on all of the time.

Also, in the specifications, it says that the OpAmp can be changed out. Does this amplifier have easy interchangeable OpAmp capabilities (just plug in)? I like to put in Discrete Op Amps in my amps.

Thank you in advance...

Ben Herrmann
Fuquay-Varina, North Carolina, USA

Hi everyone,
I'm trying to design an EQ and want to have separate line in/out PCB's and separate PCB's for each frequency band. I have been trying to design a pretty straightforward ±15V PSU with the LM815 and LM915 voltage regulators, but I have some questions.
First of all, is there any convenient/cost effective options of premade external PSU's that fit those characteristics for EU plugs so I don't have to worry about that?
Secondly, if I have +15V, -15V and 0V (PWR GND) as outputs of my homemade PSU, how do I wire the cables to make sure everything is safe? Every board will have +15V and -15V pins connected to the positive and negative pins of the IC's with two 100nF bypass caps going from each rail to 0V for each IC. Do I need a 47uF electrolytic cap on each board from rail to rail for decoupling or just once? Do I wire the 0V (PWR GND) to the signal ground (GND)? Do I run wires from the PSU outputs (+15V, -15V, 0V) to each board?
Last question, are SMD X-Caps and bridge rectifiers reliable for an audio PSU?
Thanks in advance,
Raw Coniine

I'm jumping into the deeper end of TS and looking to find some transient response information but this is very hard to come by and does not look like they are included in the original T/S parameters.

My understanding is that transient response is the time it would take for a note/signal to go from 0-100 and back to 0. I have seen some impulse response graphs that are supposed to help, but no T/S parameters.

So I had a thought that a loose approximation is at least possible. For instance we have the BL which is the 'motor strength' which is like the muscle of the speaker, then we have the MMS, which is the mass of the moving parts. Then we have the CMS, which is the strength of the suspension system, surround and spider. Between these we should be able to find SOME approximation of the ability of the BL to pull along the MMS and the CMS, right? The question is what are the equations.

The MMS is weight, the BL is strength, so lower weight and higher strength would be amazing, then we have CMS and something about CMS is that I cannot confirm is higher is tighter or looser suspension? So in a perfect world we would have high BL, low MMS and a medium CMS (so that the speaker doesnt rip itself apart?), or loose CMS. But is lower number looser or tighter?

I am currently compairing a 5 1/4 sub to a 10" sub and it looks like the 5 1/4 would be "faster" a .248 vs a .13, sound about right, right? Keep in mind I am simply looking at response rates not SPL. This does not take into account CMS, which is the X factor in this. Has anyone else tried to do this?

New Furutech AC power plugs. Perfect for DIY power cable. These are the copper version. Previously purchased from Furutech distributor. I have a few of each available. They are $60 each new. $40 each plus shipping. Please PM or start private conversation if interested.

1) Furutech FI-11(Cu) - Nema 5-15 plug
2) Furutech FI-11M(Cu) - IEC female

I have a Sony KD43 TV set. It provides me with TV (of course) and radio broadcast.
- Provider is KPN in the Netherlands.
I took the output from the TOSLINK output. To a GD-Audio non-oversampling PCM1704 player. Superb when driven by coax from player.

Some stations are good (that is : one mostly really good, KLARA) but many differ in quality. Such as Hilversum 4 (sorry couldn’t resist, radio vier guys).

—> often it is just a squemish hashbash.
Someone said this is typical of the low quality Toslink, and that I should insert a reclocker/de-jitterer directly at the output port (for instance like a plug that incorporates the box with electronics)

So I now take the signal from the decoder. Same quality difference really.

So twice Toslink output port garbage? Would surprise me.

Question:
- is the Dutch broadcast via KPN such a poor state of affairs that they do not care to ensure their input is good and only KLARA really has a well-clocked input?

I have an old pc with internet and usb out. Worth the try to dind internet-based streams?

Is that reclocker agood thing? Which?

I want to build a single ended KT88 amp and/or an 807. In the UK I can source the Hammond 1628SEA and the Edcore CXSE25-8-5K. I've seen some discussion of these two. There have been some disparaging remarks about the Hammond's top end. If anyone has experience of these I'd appreciate hearing about it. I would have liked to chose the Hammond as they have several output windings/taps, that give matching flexibility and are considerably cheaper than the Edcors. However I don't want to sacrifice sound quality if there is a big difference. Cheers. Matt

I just got a new place to live and thought it would also be a great opportunity to do some room treatment before I move in.

My idea is to cover the front an back wall in wood panels like this one here:


The front wall would be made with the wood on an acoustic fabric and act mostly as a diffuser and just giving a symmetrical look. The back wall would have the same wood and acoustic fabric, but here I plan to put 50-70mm of rockwool behind the wool wall.

The question is: I can imagine that the spacing between the wood strips would have an effect on what frequencies is reflected or maybe diffused and what frequencies that are passing through to be dampened by the rockwool. How do I find the correct spacing between the strips?

I have looked at some measurements of the store bought panels and they seem to have a fairly flat response in the mid to high frequency area, and i would expect that I can extend this to lower frequencies by adding the rockwool.

Afternoon.

one of my friends who plays bass guitar wants to use this through a mixer and into a hifi power amp

are there limitations, do's/don'ts-equipment you can/cant use?

many thanks in advance

Cardas CCGR binding posts. These are silver/rhodium plated tellurium copper, (60μ Ag, ≤3μ Rh) with gold plated lock nut.
Short version for panel thickness up to 0.175". I have 2 stereo pairs (as pictured). SOLD.

Cardas GRFA chassic mount RCA connectors. Silver/rhodium plated brass (60μ Ag, ≤3μ Rh) Teflon dielectric. Short version with thick nut for panel up to 0.10" thick.
I have 6 pairs for sale. $35 per pair.

$10 shipping via USPS priority mail.

Please PM or private conversation if interested.

I would like to build a pre-amplifier and came across these two versions:

• the Prelude by Sander Sanssen published in one of the Elektor audio specials
• the Relaixed by Jos van Eijndhoven: http://www.vaneijndhoven.net/jos/relaixed2/index.html

I don't know which one is the better quality one. But the prelude has a very expensive DCAT.

I would like to hear your arguments.

Hi fellow audio enthusiasts

I have drawn the schematics of my ML26 out of interest and it may be useful should I ever have to repair it 🙂 I would like to share as it may be useful for others as well. Use at your own risk. It is correct to the best of my knowledge, some component type number were unreadable though, mostly diodes and a few transistors on heatsinks.

Greetings,

PrimeEvil

SOLD

Asking $600 $500 / best offer, plus Continental USA ground shipping


For sale is a DIY build of the Neurochrome Modulus-86. This is using the previous version of the signal boards R2.4. It does use the LM3886 chip to provide very low distortion power of 40 Watts into 8 ohms and 70 Watts into 4 ohms. It has about 100 hours of worry free use so far. I was going to use this in an active crossover speaker project but have changed plans. I am keeping the brother to this amp for day to day listening.

https://neurochrome.com/collections/power-amplifiers/products/modulus-86

This is a revealing amp, producing what the upstream components give it without added distortion or coloration. Solid bass and extended highs as you would expect.

This is a balanced circuit amplifier and has XLR input jacks only. You can use rca input easily by adding a male xlr to rca adapter to the back of the amp. I WILL include a pair of the adapters with the sale.

The background noise is essentially not there on my 97dB sensitive speakers.

Input sensitivity is 1.8 V to full power.

The power supply uses an Antek transformer into the Neurochrome Power-86 R1.2 board. The mains fuse is inside the amp, and I use the lowest recommended amperage fuse, 5A slo-blo and have never had turn on surge or other variations blow a fuse.

The amp is in a Modushop 2U tall x 300mm deep steel and aluminum chassis. The heatsinks barely warm up with normal listening. The front panel is 10mm thick, with a red on status LED.

There are no surge suppression or speaker out protection, but I have never needed it with these level Neurochrome products.

Weight of the amp is 22 pounds, and it will ship in a 20 x 20 x 12 inch box to the Continental USA only.

So after a couple days of waiting for parts to arrive, I finally put everything together and it works! But there's a small problem, The tweeter, and the woofer started to make a small hissing noise. The hissing starts to get louder when I connect the Bluetooth module to it. How can I fix this ? thanks all

Pcl82 various brand.
Ask for price.
Plus shipment in Europe

SOLD

So I ran across a Taramps Bass 3k used on egay for cheap and bought it to either have a spare amplifier or to flip it to one of my friends. Amp came in, it is totally dead. No power lights, protection lights, nothing. eBay seller gave me my money back and told me to keep it. So I now have a free dead amplifier. Before I toss this thing, does anyone have a clue what could be wrong with it? I don’t see anything obvious. It seems to be in almost pristine condition like it was bought, connected, found to be dead and returned to the store. Some of the plastic wrap was still in the box and the plastic is still on the logo.