I have a collection of parts in my shed and I'm spitballing a wide coverage array to use what I have.
The idea is to use QSC clone horns (something like 50x90 pattern) in a triple trap array with the horns turned vertically.
Each horn unitized with a pair of Celestion 4" sealed mids, 450Hz XO for each horn unit to an MTM pair of 10" midbass, perhaps horn loaded.
They would be mounted as high as possible at the side walls and angled down at the center of the floor in a 60x100 room with high vault ceiling.

90deg vertical is unorthodox but maybe can use this to advantage to get around needing front fills?

How do you think the horns will behave in this configuration - the horizontal pattern overlap, and combined gain/directivity where they lose their individual control 1-2kHz?

I've got an earlish GK 400RB, same one as in this thread at TalkBass. See image from that thread below. Q1 - anyone know which version this is?

GK 400rb troubleshooting help needed

Now mine is a whole lot scruffier; had the transformer changed (now torodial) to run off local voltage (230VAC vs 110VAC); has been blown up at some time; but mostly works.

Except that notes are a little distorted as they fade away. So there I am thinking that maybe bias might be out & its running slighlty in class B. It sort of almost sounds like that.

Put it on the bench today and I find there's c. 250kHz at about 20mV pp on the output. And when I feed in 600Hz sine wave with about 100mV pp output, the signal both gets the noise added and the signal itself is not stable. The effect out is clean as a whistle, but the main out has this noisy 40us period signal. No surprise: none of the front panel controls affect this in the slightest.

So, I popped the top to have a look. The repairs are OK, looks like 1/4W resistors went BANG. Lots of scorch marks on the PCB.

But: it looks like there is a space for another 5W resistor to the left of R30 (5R zobel?) and the four emitter resistors. Noting that the image linked above also only has 5 big resistors.

I've checked the earthing of the case components and that looks OK (that's known to cause hum problems)

Anyway, before I do any more poking around I thought I'd ask if anyone else has seen a GK have this sort of oscillation?


Edit - a view under the hood of mine.
I think the scorch marks are under the resistors in the bias setting ladder. How on earth do you cook them?

I recently acquired a lonely Acurus A250. It was orphaned from a co-worker who upgraded. The power switch rocker has a green indicator light that flickers. It came with a piece of black tape over the indicator!

I tried to find an inexpensive replacement switch. Its sort of an odd configuration. Black body and black rocker with a green light, 22 x 30mm cut out.
I found out that this switch is easy to disassemble. The power to the lamp in the rocker is via two coiled springs, the springs penetrate the back side of the rocker and the leads for the incandescent lamp and a series dropper resistor are just looped through the spring leads. No wonder it flickers. While testing, the incandescent bulb went open. I just replaced it with a green LED, a IN4007 and a 470k dropper resistor. No more flicker and seems ok. Potted those parts with hot melt glue in side the rocker body. Only issue is that the shade of green doesn't quite match the green of the Acurus pre-amp.
Close enough and no longer annoying
P

I'm comparing the design concepts between using lower order filters with an amount of EQ networks and using higher order filters without or less EQ filters.

The EQ networks mean parallel and series notch circuits, impedance equalization (zobel), and contour circuit.

In brief, I found Thiel speakers utilize lower order filters -- first order -- with a plenty of EQ networks, the brochure states there are about 40% of crossover components being the EQ networks. Compare with my speakers, Braun/ADS, they use second-order filters but without or a bit of EQ networks in some models.

So, I wonder what's the better concept, in theory and practice?

Came across this web page while looking for an AC30 top boost channel schematic:
https://www.voxac30.org.uk/vox_ac30_circuit_diagrams.html

Nice page.
Top boost looks pretty similar to the Bassman preamp.

I have for sale a couple of pieces of test gear.

Heathkit IG-18 audio signal generator. This is a classic signal generator that has been "greened" (i.e. improved). I did this several years ago and don't remember all the particulars but I did install the new PCB from the guy in Canada selling the kits, along with all new electrolytics. $40 plus shipping

Hewlett Packard HP400E - working condition but unused for several years. $25 plus shipping.

Hi,

I have 10 pairs of NEW MJL2119-3G and -4G onsemi transistors for sale, They where all bought from Farnell about 13 years ago, been laying on the shelf since. I would sell these for 5usd each, items are located in Norway but, can be shipped to more or less anywhere, buyer pays for shipping. PayPal prefered.


Thanks,
Stian

SOLD*
Spare set of Miro PCM63 DAC for sale. i2s inputs on board.
Circuit design and board info available here:
https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-209#post-7049224
You need a PSU and I2s source and a pair of single op amp for this DAC to function. Look at the info in the thread to see the PSU requirements.

Board fully populated with good quality caps eg. Panasonic FC, Panasonic FM, Nichicon KZ, Kemet mkp caps, Epcos film caps, low noise non-magnetic resistors, panasonic smd ceramic caps., good quality Nextron IC sockets.

You will be supplied with a pair of unused PCM63P-K chips. They are 100% new, with 'virgin legs' and you will need to press the legs inwards to insert into the IC sockets. Please see the pictures showing the legs. I used my own pair of PCM63 to test this board and will not send these to the buyer.

Please note that I will not be providing the IV op amp.

Price is $200USD, including shipping registered worldwide. Pictures to follow.

I'm designing a fender based preamp and want to use both types of tremolo found in the amps but don't want to use a tube in each lfo so I had the idea to combine both circuits into one and be able to switch with a 3pdt switch


How viable is it to do this sort of thing? I made the change from one to the other on the breadboard and it works but I don't know if it works the same on a pcb with a switch or it may have a failure with time of use
Another question that I have is how can I implement the modulation of the second lfo in a vibrochamp circuit?


so far this is the entire circuit, I would like to know what I am doing right and what I am doing wrong
Thanks

Is there a way to speed up the process with new carpet?

All I can think of is try spreading it out in a lesser used space, maybe run some kind of air circulation.

Its otherwise unconcerning unless things like a baby might crawl on it or if ppl have respiratory weakness? I'm pretty sure any of the airborn vapors ( some call it a pleasant new carpet smell?) can't be helpful towards that.

Hi I have listed a full new and unused minidsp kit over on ebay

https://www.ebay.co.uk/itm/304928918487?hash=item46ff2e0bd7:g:8OQAAOSwb5FkUjL7

dsp board
dac boad
vol board
remote
connectors

B&D sander circa 19??.

Hallo allemaal,
Ik ben Roberto en ben helemaal nieuw bij jullie, lijk me leuk hier en ik denk dat ik veel van jullie kan leren.

Tony McPhee, the singer and guitarist who led the blues and rock group the Groundhogs across six decades, has died aged 79.

https://www.msn.com/en-gb/entertain...r&cvid=0c32e388ea154857b27751f175f67b97&ei=28

Good day. I am working with a Hertz HDP4 4 channel amp a couple of day now. It uses 4 IRS2092s drive chip which drives 2 IRF14019H dual mosfets in parallel in each drive. In my initial repair, i replaced 4 of the mosfets and 2 drive ic that where burned and deffective. Upon power power on , I see the gate and output signals clean and good from the mosfets but after a couple of seconds the signal becomes distorted kind of oscillating too much wherein no signal is fed yet. All of the channels have same issue, I tried to feed an 50 hz signal but not seen any signal output. I checked the mosfets and drive chips , in my opinion are all good. Am i having an issue on the output section or in the preamp section? First time i encounter this oscillating issue. Please need help from guys who have same issue on Hertz amps. I will post later the output signal from the mosfets if you need them. Thank you very much.

I have built a turntable using parts from an old Rega Planar 2. I can't get the stylus to follow the groove, and it keeps skipping back so that it repeats the same bit of music.

I have tried all the anti-skate settings, and while that makes a very slight difference, it doesn't solve the problem.

The turntable is level, the tracking force (Audio-technica VM95 E) is set to two grams, and altering that doesn't stop the skipping.

What else can I try to resolve the issue?

The wood glue thread has me curious... What do you guys use to clean your records? I use a Spin Clean with my own home-grown solution and it's been very functional, but a couple times I've had records it couldn't clean. Is there a better solution that isn't thousands of dollars than a Spin Clean?

I'm looking for some Twisted Pear Rhea boards. Happy to consider bare boards or some populated with decent 45/49MHz oscillators.

Alternative 'generic' boards of the correct footprint will also be of interest.

Asking before I turn to KiCad...

Cheers

I have a dumb question but I'm sure someone here will most likely know the answer.

If you had say a polk center, that's a 2 way. That means it has a crossover, right?

Now if you remove the driver (not the tweeter) completely from the crossover and hook it up without the crossover at all. Does that speaker driver now become a full range speaker?

How does that work with full range speakers no crossover.

I know this may sound dumb but I'd really like to know.

Looking for two triplets of each.

Sadly hifiengine.com still does not accept creating a new account for me and I get all manner of problems like huge IP-spans being blocked because of abuse or account not registered when I try to login with my existing HifiEngine account.
I would like to ask some kind soul on here to please download the following service manual from https://www.hifiengine.com/manual_library/sony/tc-50.shtml for me as I am in the process of restoring two (or maybe combining them into one working one) of these at the moment!

The service manual I am missing is: https://www.hifiengine.com/hfe_downloads/index.php?sony/sony_tc-50_service_51001_on_en.pdf

If you can then please send to [REDACTED]"!

Thanks in advance!

Hey all, Just joined the forum as i'm looking at making some custom stuff for a project including a DAC,
I'm going to rebuild my car electronics and looking at putting a PC with a proper DAC in it.
The main issue is, my car (Saab 9-5) is more towards pro audio so i'm looking for a quad channel DAC that has balanced outputs.
Does anyone know of a project i can use for a base or got some tips on starting my own project?

Hello All

Going to start build lots of ideas running threw my head ill just but this out there first 11" wide 16" depth 60" tall the speaker placement is different on real wood.

the amps a vsx 531 130w per channel front, center, rear, sub out 6 ohm max sub output will go to car amp attached to

psx 160 amps available the side woofer will be powered car amp 800watts per channel

the speaker will mirror each other when I get home ill take more pics to show work still need the amp and figure out how to make the box around the front piece just starting out hear
I have a crossover set to 8 ohms and all speakers setup an the high mids and low are all around 7.5 ohms
Does this sound OK to do

Live in London Ontario Canada just staring this journey still need to make center and rear after this only other experience is a arcade cabinet build with woodworking
Thanks For any info and help and your time
Thanks John

Hi all-
I picked up a Marshall valvestate 80v 8080, and I'm trying to troubleshoot a couple problems.

The clean channel is not working right, and makes this very weird sounding distortion;

Login to view embedded media
With the volume turned down low, it makes a really egregious amount of hiss and low signal, with this distorted sound punching through, and then higher, it's all distorted. I did try cleaning the hell out of the pots and they are giving me normal resistance readings.

I checked the voltages on IC1 (a TL072) and it's showing -15v on pin 4, 15v on pin 8, and nothing on any of the other pins, millivolt readings. Is this indicative of a fault in the opamp? I have seen in other threads that there are a lot of cases of that opamp blowing in this amp for some reason. The opamp in IC2, on the other hand, is a different story, I think it has normal voltages - could someone tell me what to expect?

The other problem is a buzz that sounds like a ground loop, when using the boost channel, which sounds pretty good. It would be nice if it was related to problem 1, but I doubt it. I know this has been covered in other threads, but it would be great to get realtime feedback on what to try.

I have tried:
1. replaced the filter caps.
2. Tried re-flowing the solder on those big resistors that get warm R119, R120
3. Tried this grounding workaround noted on other threads, but I'm not sure I'm doing it right (remove a ground somewhere else?)

4. Tried different 12ax7 tubes

The transformer is one of those guys that hums/vibrates audibly/mechanically with the amp turned on. I notice that this buzz is there at low volume with the amp turned on, everything turned down; turning up master volume does not affect it. But with master up, the volume on the boost channel (the working channel) increases the buzz. I'm not sure I understand this metal plate that the pots are all mounted to - it's like a ground rail with the pots 'isolated' from the chassis, but I get continuity there all around.

If anyone has insights on this well-known amp, would be glad to hear them. Schemo attached below

?

Hi all,
Digi-key has just informed me that various Nichicon production for audio use (FG and perhaps other audio series) will cease production, but I don't quite understand if Digi-key will no longer keep these series or if it is Nichicon that will cease production and whether there will be substitutes.
Does anyone have certain or official news of what is happening?

These little speaks are the passion project of Matt Jabloner of @MattyBlue LLC.
-
The sound is most impressive considering their dainty dimensions, just 30" tall with about a 5" x 6" footprint. And they sound great with both the S.E.X. amp and the Stereomour amp we tried them with.
-
We're working together on an initial run of five kits. The all wood (no MDF!) cabinets are premade in Matt's amazing CNC shop. They will ship "knocked down" and they pretty much snap and screw together. Drivers are some highly regarded Mark Audio units. Price is TBD but should maybe be around $800 the pair or so
-
More info will come as we refine the details.

Trying to find a pair of the 10” Vifa drivers used by Tact/Lyngdorf in their w210 comer woofers

Has anyone got a schematic of the Icon Audio Stereo 40 (mk I, II, III, or IV)?

This amp is fairly conventional, except that it has a three position switch which can be used to select "H", "L", or "0" feedback. It makes for a very interesting listening experience to switch between the three.

I would like to see how they implemented this feature.

SO, schematic anyone????

Beyma Tpl200b. Special version with brushed steel plate, steel grille and revised back chamber with optimized sound absorber.

New, only opened and measured one.
The price for the pair is: 700 euro
European shipping costs 25€, international shipping costs 55€
Shipping to europe is 25€, international shipping is 55€, if you want insured shipping please ask for the price. Payment by PayPal, satispay or bank transfer in advance.
my email is franco.cauda@gmail.com

FOSTEX T90A it reads 7.1 and 7 ohms . will go out to 30k.
320$ shipped in the USA

Hi guys .... I am having a rough time with these STK0039 ICs' . I have ordered a set from China and ebay ( wasting my time and money ) with them failing from the get go.There has to be a schematic with discrete components I can build. I see there is one for the STK0050 but the circuit is a bit different than the STK0039. I love this Pioneer SX 680 AND HATE TO SCRAP IT . Can any one help ?

Hi

This amp cannot start up. When power switch is pressed, the red light comes on, then the red light goes off and the blue light comes on and this keeps repeating continuosly at each second. Sound comes on during the blue light and cuts off during the red light. One thing I realise is if I remove the NE555 ic, then the blue light comes on and stays. I am unable to get the schematic, but the attached schematic looks quite similar. I guess the NE555 provides a delay start and protect. Any advice.

Thanks

I don't know if anyone else has this issue, but it happend to me recently.

I was getting my haircut and suddenly felt very light headed. I almost passed out, but didn't lose complete consciousness.

The barber stopped cutting my hair and I moved onto a couch for a few minutes. After a while the light headedness got somewhat better and I returned to the barber chair and he finished the haircut. I still didn't feel completely normal, but was able to drive home. Eventually the feeling cleared up completely.

I mentioned it to my doctor and he said you have Hair Cut Syncope. It's a fairly rare, but well understood condition. He said it's probably from the sound of either the scissors or the razor.

So if anyone starts to feel light headed or dizzy next time you get a haircut that's probably the reason.

https://www.healthline.com/health/what-is-hair-grooming-syncope

I Received some Snell Type E IV speakers from my neighbor for helping them with some yard work. They were in the basement and pretty rough. Scratches and chips on the veneer, grills completely destroyed, surrounds dry rotted, etc. I got the cabinets sanded and refinished, veneer chips filled with Quick Wood, working on the surrounds and grills next. At any rate, my question is, I just noticed one of the speakers is missing the felt around the tweeter. I've looked online and cannot find this part. The thought of using felt weather stripping came to mind but the 90-bend radius is pretty tight, it almost needs to be cut from a sheet. Any ideas?

Also, the super tweeters on the back were pushed in. I sucked them out gently with a vacuum but there are still multiple dimples, any concern there?

Does anyone in UK or EU have one of these spare? For M2 build. I have one already…
Thanks 🙂

I'm hoping someone who's worked at a place making appliances like a disc player can answer this question. There are countless appliances for AV stuff that are Class II (no safety ground, "earth") and are made of sheet metal and have internal PSU's. The definition across the internet is "they have plastic enclosures"..... So you see where my question comes from. I'd like to know how they're doing this so they can get the double box on the back.

Thank you

I can calculate a Helmholtz trap with holes on the mh audio homepage.
But I would rather use slats than holes. But, the slat calculator is not logic to me.

Can I just use the percentage of perforation for slats instead? I would like to avoid drilling hundreds of holes

I am working on a NAD 7400 that has low output in the left channel. I believe have tracked down the issue to a 2SA970 that is serving as a current source.

Reading through other threads (most of them very old) there are mentions of other (now) hard to find replacements. Is there any jellybean type transistors that would easily sub for this?

Most critical spec is going to be the collector to emitter voltage, there is almost 60v across this in the working channel.

As mentioned in the JLH thread, here is a block diagram of the method I have used to set up curve tracing using a standard oscilloscope.
The idea is straightforward but has several blocks. An oscillator is set to 50Hz and drives a power amplifier which is A.C. coupled and stable when operating a highly inductive load. The ouptut level control on the oscillator is used to adjust the voltage applied to the transistor under test.
A transformer is used which in my case is a 50W split bobbin with 115+155 and 25+25V windings. The terminals are all accessible (the primary by a voltage selector switch and the secondaries by separate 4mm connector sockets) so that the unit can be connected as step up (so giving a maximum output approaching 200V AC) or step down (up to about 5V output from the PA at 20V output using the 115V input option and secondaries in parallel (can test at up to about 5A) or 10V at 2-3A) or 1:1 using one secondary as the input and the other as the output. The amplifier is a 50W 8 ohm unit.
The transformer output is bridge rectified and connected to the transistor under test. This is arranged with an emitter resistor of 1ohm (can be 10 or 100 for low current devices or 0.1 ohms for high current) with the emitter connected to ground so that the oscilloscope common can be earthed (many scopes don't accept the screen voltage at anything other than earth).
The base current for the transistor is supplied from a separate power supply which is variable (I use 0-12V) and a suitable current limiting resistor, usually with an ammeter connected in series to measure the actual base current.
The oscilloscope is set to X-Y mode. The X input is taken from the collector. The Y input from the negative of the bridge rectifier/ emitter resistor connection and as that would give a negative reading with the emitter common, the Y channel should be inverted to make an NPN characteristic look correct.
The transistor should be mounted on a heatsink. A typical error is for self-heating to change the characteristics which may give pessimistic readings for the Early voltage for example if the gain increases when warming up. Therefore, I never use the unit in continuous running mode, but wind the voltage up and down using the level control on the oscillator to provide a sweep just long enough to photograph. By stacking several images a set of curves can be obtained.
Obviously, the problems of looping , and high frequency oscillation are practical effects which need to be considered. Looping can be minimised by the standard methods (search the web if you don't know this) or simply averaged in Excel for example if you can get digitised data. Oscillation can occur with high frequency transistors and that needs to be addressed by careful wiring, or possibly by shunt RC snubbers to keep the collector impedance low but excluded from the transistor measurement wiring (i.e. across collector to bridge rectifier negative).
For PNP, all polarities are reversed.

Hello all, long-time lurker here. This question is about the acoustic properties of glass bricks.

I'm building a project studio like a Newell non-environment. This would feature monitor speakers built into solid walls straddling the corners of the front wall, angled towards the listening position.

These walls would partly cover each end of an existing window, which takes up most of the width of the front wall. I would like to preserve the daylight that the window brings. So I considered building the wall from glass bricks. These are the square cca 200x200x80mm blown glass things with an airspace inside and a lip around the square perimiter for joining with mortar. Such a wall would be plenty heavy (tick), but I'm not sure how to work out if the bricks or air inside them could be excited into any unwanted resonances by anything that happens in the studio.

Any ideas, or does anybody have any practical experience with these bricks?

Pair module NC500MP OEM - 270W/8 ohm - with internal PSU. Price list 375eur/pair, asking 225eur/pair + shipping

https://www.hypex.nl/products/amplifier-families/mains-powered-ncore-family/nc500mp-oem

I have built a small amplifier with a pair of ECL82/6BM8 valves in single ended configuration and a EZ81 rectifier valve (with 50uf - 3H - 50uf filter) PSU
I notice occasional pops from the speakers when switching the mains off. I suspect this is coming from back EMF from the power transformer primary, causing short duration spikes on switch-off. My transformer is a Hammond DAX370, with the primary configured for 240VAC
I am considering fitting a 100nF + 100R snubber across the 240V primaries. Has anyone any experience of using a snubber this way?

HeatsinkUSA Summer Sale Automatic 10% off ALL heatsinks now through June 30th. No min order required. Does not apply to service add-ons such as machining, deburr, etc. www.heatsinkusa.com

Does anybody interested this amp.
I have just seen boards of them on my DIY market but they don't have a schematic

If I have an opinion I'll photograph them for compare with original Gamut D200

Happy...Diyers
ANALOG GUY

SOLD

For sale two waveguides, un-used. These waveguides are well known for their excelent performance, they are a clone of a QSC waveguide and some measurments can be found here: https://www.diyaudio.com/community/threads/jbl-m2-for-the-poors.247050/page-38#post-6267592

They are no longer available but they where at one time sold by Parts express: https://www.parts-express.com/B-52-PHRN-1014-10-x-14-Plastic-Horn-Waveguide-299-2303?quantity=1

I'm looking for £40 for both, postage included within the UK or can be collected from Warrington WA4.

SOLD

I have a brand new Elekit TU-8600S for sale. Please contact me for detials.

Greetings and Salutations!

A noob question please:
I've got a huge toroidal transformer 2000VA 36V/55A just laying around.
Looking to build a basic linear PS to power two class D amps for a pair of bookshelf speakers and a sub.
Have some basic soldiering skills.
Can really use any advise on kits, parts.

Thank you
Dennis

For sale is a pair of Markaudio MAOP 11.2 bought in October 2021. They are in perfect condition and have roughly 75 to 100 hours run time. Asking EUR 200 plus shipping (from the Netherlands).

Hi,

I have 15 pairs of MJ2119-3 and -4 transistors for sale. These where bought directly from onsemi december 2010, and have been laying on shelf since. I would sell these for 5usd each, items are located in Norway but, can be shipped to more or less anywhere, buyer pays for shipping. PayPal prefered.

Stian

Can someone please send me a schematic for the output module of a EV pa2250t amp

I need a practice amp/speaker for my electric cello. Guitar amp combos are a common solution, but they're intentionally designed to produce a "tone", which isn't great with Cello. Some electric-cellists use PAs or Keyboard speakers, but the used market is no good for those.

I'm looking for driver suggestions. Goals:

• Similar form factor to my Marshall (480 x 420 x 225), or smaller
• Not very expensive. No boutique $200 drivers.
• Flattish in the cello frequency range (65 - 880hz, plus harmonics), I'd probably be fine with it not reaching the full 65hz)

The first option I thought about just using a guitar amp speaker like the Celestion Ten 30 (perhaps mated to a tweeter or small fullrange). Alternatively, a Peerless SDS-160F25PR01 models remarkably well down to 65hz in a small box, but I'm sure there's a catch.

Any recommendations or thoughts? Cello presumably shouldn't produce the same speaker-killing dynamics as electric guitar. I have a spare 60W@8ohm stereo pro-audio amp that I intend to use. I have plenty of guitar effects pedals, so I don't need any built in reverb

A cellist on youtube uses this amp: https://www.thomann.de/gb/dv_mark_ac_101h.htm. I guess that's a target to aim for

Was Missing doing designs with more Old School woofers.
Mechanical designed for massive bass in simple cabinets.
No Reflex , No transmission line or anything exotic.

Also was reminiscing my childhood.
Remembering the Radio Shack Catalog.
Which sold Raw Drivers for Diy.
And night after night dream up speaker builds.
Wishing to build all kinds of imagined systems.


Lots of the Big 12" and 15" woofers in the
Catalog were basic foam/ rubber surround poly cones
And so I was reminiscing and looking around
At Parts Express for, Fun easy Poly cone
hopefully cheap...with rubber surround.

Which resembled all those late nights
dreaming things up from the
" Shack" catalog
But somewhat modern easy approach
Full range assisted by a woofer

So I found a Fun 12"
12PR-8




To give Support to a 2.5" Woven Fiber/ Poly
Fullrange / Wideband
PC68-8




Modeled the 12" in simulator.
And ohh boy it is one of those guys.
Sealed, overemphasized
the bass area.
So in the real world half space, seems flatten
out pretty good, Baffle step around 280 Hz
No ports no BS just bass
All 140 liters of it



Using a 500 x 800mm Baffle
I started the usual " Virtual process"
of full space ,baffle diffraction, crossover...
yada yada yada

Well the summed up pretty So decided to
Draw up some pictures. To see if Im dumb
enough to build this Thing

The 1000M's are 8 ohm, 90db sensitivity, and are said to have a benign impedance curve. The sound is very transparent. I really like these speakers and I plan on keeping these for the long haul.

Preamp is a Benchmark DAC2 HGC.

Room is 13' x 14'.

I listen at less than 75 average db at my seat.

I listen to a variety of genres - mostly dreampop/shoegaze, but also jazz, blues, folk, classic rock, alternative rock.

Should I go with the M2X, F5, F6, or Aleph J? Or something else?

Hey there,

has anyone got any ideas on how to increase output power for the Blueglow design? sorry if this has been asked before, my speakers are 87db and ideally another 5/7 watts would be great.

cheers.

I have these 2 faulty mosfet power transistors they I’m trying to find an identical match for but am not very knowledgeable in component matching. I’ve bought what I thought was a straight swap that matched the number/letter scheme on the top line IRFP460 with only the second line not matching up but I now keep blowing fuses on my system. Could anyone help with what is a direct replacement or what do the Y58K BQ numbers/letters mean on the line below as I am not able to match these with a new component.

Hello,
I sell various LDOVR voltage regulators (DC/DC).

They are the previous version of the current one, available here => https://www.ldovr.com/product-p/lt3045-1a0g.htm
Although... honestly I don't see any diff btw "old" vs "new"…
Each regulator has 2 LT3045 in parallel, thus the limit is 1A max / reg.

LT045, from Analog Devices, is one of most efficient LDO on the market : very low dropout, high PSSR, etc…

Various LDOVR can be parallelled to increase the load.. to 2.. 3A.. and so on.

All the LDOVR have in/out connectors soldered.
All in mint condition

For sale =>
=> 9 items / 3.3 VDC fixed output
=> 4 items / 1.2 VDC fixed output
=> 1 item / 5 VDC fixed output

Price => 15Eur / item, shipping included with tracking No
Payment via PayPal.

If you take them all => you can ask for a "special price" of course.

I'm located in Paris surburb (FR).

Shipping :

• free (-4Eur/item), if we can meet in Paris area
• to be det., depending on your location / only to european countries (simply because I have no clue about shipping pricing worldwide 🙂 )

Interested, questions about the product, would prefer a nicier price : just ask via message or email.

Rgds

Hello,
I sell a few modules from MPaudio (HPULN).
=> 7 units of the ALD-HPULN
see here => https://www.mpaudio.net/product-page/ald-hpuln-ps
=> 1 unit of the SLS-HPULN
see here => https://www.mpaudio.net/product-page/sls-hpuln-ps

All => mint condition

Price => 100Eur / module, + shipping (with tracking No.)
Payment via PayPal.

If you take them all => you can ask for a "special price" of course.

I'm located in Paris surburb (FR).

Shipping :

• free, if we can meet in Paris area
• to be det., depending on your location / only to european countries (simply because I have no clue about shipping pricing worldwide 🙂 )

These linear regulation devices are quite well known / high quality / versatile (output can be set to any output voltage thanks to a trimpot)

These modules are designed with various LDO LT3045 in parallel.
LT3045, from Analog Devices, is one of most efficient LDO on the market : very low dropout, high PSSR, etc…

Of course the heat sink dimension is not huge, but far enough sized if you use upstream a source of current not too far from the output DC voltage.

Upstream source of current can be :

• a toroid (AC source)
• or a DC source

Please note that all the HPULN I sell are "AC/DC".
Thus, you can use upstream either an AC or DC source.
Of course, if a DC source is used, keep in mind that the rectifier bridge drops the input voltage by 0.8VDC before reaching the LT3045 stage.

All my HPULN worked on low charges. In average to deliver 0.2A to 0.5A.
The heat dissipation never exceeded 3W / module, depending on the AC or DC source.
In most cases the heat sink remained "mild / cold", never "hot" (anyway, it's useless to use a too big voltage drop).
The average voltage drop through the LT3045s (except rectif. bridge) was between 0.7 & 1VDC, and results were perfect as such (see datasheet of LT3045 for more info).

Interested or questions, just ask via message or email.

Rgds

I have a Cyrus PCM II CD player which I have always thought was very good.
Unfortunately, I haven’t been able to use it for several years as the laser has gone on the blink – it will only rarely play a CD. I replaced it with a NAD C521BEE which I don’t think is as good.

This is annoying. One small part is stopping me using the Mission. Mission say they no longer have the lasers – which I believe were made by Philips – and so can’t repair it.

So… does anyone know where I could find one? There must be one somewhere in the world.

Thanks.

Hello!
Utter newb here.
I've started work on a project I've had for a while - namely converting a pair of Genelec speakers into bluetooth (heresy!!!!), battery powered ones that auto-pair with eachother (think airpods).

To carry the speakers, i've gone for a Nanuk 935 case (peli 1350 equivalent), and once the speakers are out of the case, i'll have a lot of usable volume within it which would come in handy to expand this into a 2.1 system (the BT boards i'd be using allow for this)
The case itself, when empty, has ~28L volume. Of that, a small portion will be reserved for the batteries, transformers, and componentry necessary for the sub to function. The rest will be filled with some sort of open-cell foam to keep the speakers secure during transport.

I will reinforce and dampen the sides of the case as much as I can, but given the material of the case there will still be a substantial amount of flex, at least when compared to something like MDF.

How would you approach this? Initially I was thinking of just winging it by calculating volume w/foam and buying a couple of those TB sub + passive rad kits, but i'm unsure whether that would be a good idea. I briefly considered a port, but i'd be running into issues with internal layout interfering with port length, plus it'd be nice to retain a modicum of water and dust protection.

Any idea on which foam and driver/s would be best suited for this? Keep in mind i'm limited by the size of the case, so even 8" would be pushing it.

Thank you very very much!

What does Stonehenge sound like? https://www.bbc.com/travel/article/20230601-what-did-stonehenge-sound-like



dave

Hello! In order not to multiply the topics, please answer which the name of this tonearm?:

Thanks in advance for your reply!

I'm designing a ported bookshelf speaker and I'm considering the Seas CA15RLY for the midbass. Using WinISD I modelled the three default alignments (QB3, BB4, and C4). All result in a box of around 7.5 liters and with similar F3 points. I'd like to get a bit better low-end extension, so I increased the box size to 12 liters and lowered the tuning frequency to 48Hz to arrive at a nice flat response until rolloff. This results in an F3 about 10Hz lower.

This will ofcourse increase Qtc, and impact bass transients negatively. But I have no idea by how much. I googled screenshots of older versions of WinISD and the Qtc used to be shown on the 'box' tab, but it isn't there anymore (I'm on version 0.7.0.950). Can I still find Qtc in WinISD somewhere? Or is there another program that can be used to calculate Qtc given the driver T/S parameters and a certain BR cabinet?

Fender Hot Rod Deville 410 Clean Up

My son bought a used Fender Hot Rod Deville 410 original and we are going to go over it since he says it doesn't sound right. Googled it and many say that it it is similar to a Blues Deville but that one unused half of a 12AX7 was added for even more distortion in the drive channel and they went too far on gain. Some suggest replacing the tubes with 12AT7s but he tried that and one in the second stage seemed alright but that it still was not right.
Another person suggests changing the second pre amp tube to a 12dw7/7247 which puts a 12AX7 half in the clean channel and the 12AU7 half in the distortion channel where the lower gain fits well. We will try this.

I opened it and noticed a date of 1996 on the circuit board, not sure if that is the date that it was designed or the actual age of the unit which would place it just shy of 20 years old.

First impressions are that the jacks feel very cheap, and I don't like the circuit board from a reliability perspective but I suppose it works.
Speakers are four 10" Eminence for Fender. He wants two 12" but I don't think I'm up for making a new baffle board we'll see.

The red printing on the output tubes is burnt to brown in some areas and I have a feeling that it was red plating.

All the main signal paths are tubes 12AX7 preamp and 6L6GC outputs, but the reverb, pre out and power amp in all employ TL072 OP amps. Fender seems to like these as they are in many of their newer amps. I believe that these snap rail to rail when over driven, IIRC, anyone know for sure? Let's hope that they are never over driven.

Pulled the tubes and they are all Groove Tubes, 12AX7s say Sovtek on them not sure about the 6L6 GC but my friend noticed that they had welded plates - nice! One pre amp tube tested weak and the outputs tested fine - still I believe that they need to be tested at full power since the tester doesn't stress them as in circuit.

======== Schematic Walk Through
Schematic from Fender is here in .pdf:
http://support.fender.com/schematics/guitar_amplifiers/Hot_Rod_DeVille_schematic.pdf

Output plate supply is 485V! I'd prefer something closer to 440V.
Even the preamp supply seems high at 388V.

The input stage looks like typical Fender with the 1 and 2 jacks but they've combined the typical
two channels into one with relay switches to raise the gain for the dirty channel.
V1A has the typical plate and cathode resistors with a large cathode bypass cap of 47 uF providing
increased gain over the full frequency response. This is larger than needed but they probably are
going to roll- off the low end with the interstage coupling caps so that is fine. Looking closer all
four preamp stages have the typical 1.5K cathode and 100K plate resistors, smaller cathode bypass
caps are used to provide response shaping. The response effect can be calculated here:
Cathode Bypass Capacitor Calculator
There are two front end pots, gain for the clean and drive for the distortion channel allowing the player
to preselect two different volumes depending on which channel is selected from the foot switch.
It is interesting that the low frequency roll-off is quite different between the two channels and also
the much lower value than typical, grid leak resistor makes the roll-off frequency dependent on the
pot settings. Here are the values for low volume settings:
Clean: .022uF into 470K for 15.4 Hz
Dist: .0015 uF into 430K for 246.8 Hz
Minus 3 dB can be calculated here:
High Pass Filter Calculator
This blocks LF from the distortion channel since bass does not sound good when distorted but I have
to wonder if they went too far.

R44 could be increased to make the LF cut less dependent on volume position, perhaps it was deliberate
to keep it clean at higher volumes? To keep the cheap speakers clean, just speculation?

The Bright switch puts in the second stage cathode bypass cap but it is disabled when the distortion
channel is selected. The cap is a small value so that it only boosts the high end.

Output of the second stage feeds the tone stack which looks like the usual Fender arrangement.
The relay switch that disables the Bright control also further cuts the high end by enabling C3 as a
shunt at the input of the 3rd stage. Presumably to cut the highs that might get too harsh with more
distortion.

This amp has the amusing, "More Drive", option where a 1 uF cathode bypass is enabled on stage 3 by
Q1 and a 22 uF cap on stage four through Q2 - JFET switches. There are actually two foot switches, one
to select clean or distorted channels and the other to enable "More Drive".

The fourth preamp stage is only used for the distortion channel and it is removed and muted by the
second relay. A Master Volume pot is provided at the output of this fourth stage and therefore does
nothing when the clean channel is selected. This allows the distortion channel to be driven very hard
without being forced to drive the power amp to full output. Turn up the drive to get as much distortion
as is needed then turn down the Master for a comfortable playing level. Interesting to note that the AC
signal voltage shown at the plate of the fourth stage is 17.1 V. This is probably enough to blow out the
inputs of the TL072 OP amps since they only run on 16V supplies, so back to back Zeners clamp the
signal at +/- 15V, I might have chosen 10V to keep the levels more reasonable.

The output of the final output relay is attenuated to feed a TL072 buffer U1A for the Preamp output
jack, this is not in the path to the power amp.

Interesting that the relay output is not attenuated to feed the TL072 driving the reverb spring, is it
normal to distort the reverb driver in a Fender amp? If not I'd probably attenuate that drive signal
by 6 to 12 dB. I'd also use a more robust driver, something like a headphone driver for the reverb
drive OP amp. I'll have to check the gain of that stage perhaps it is unity gain, not sure since I don't
know the impedance of the reverb tank.

OP amp U2B amplifies the output from the reverb tank to the Reverb pot the output of which is
mixed into the power amp input. Some response shaping is used.

OP amp U1B is an input buffer with gain for external sources feeding the power amp.

The power amp is very close to a standard Black Face, no ultra linear connection, but with a few
very small 47 pF caps added probably to tame the massive harmonics from the distortion, and
a few diodes added probably to protect the tubes and output transformer from arcing if the amp is
ever operated without a speaker load.

I picked up 3 Ashley fet2000 amps a couple years ago and really love their sound quality - and the headroom they provide when driving some Martin Logan SL3's.

I already replaced the fans with DC brushless versions to eliminate the noisy fans. Even added an adjustable AC-DC supply that allows me to dial in the fan speed.

The last thing I would like to do is find a way to minimize the transformer hum that is slightly audible when the room is rather quiet.

This is not a hum that comes through the speakers - but something that you can physically hear come from the chassis.

Is there some sort of isolation fastener that can be purchased that will help minimize the transfer of this vibration/hum into the chassis?

It seems like de-coupling the transformer from the chassis would help isolate some of the noise.

I have been looking around online and also found another thing that may help eliminate this is to re-dip the transformer to help cut back on the vibration of the windings?

The transformers in these things are absolutely massive. As in: as large or larger than the transformers of many small 90 amp wire welders. No joke.

Ideas? Links? Any help appreciated!

-Dean

Wirewound SQP (cement) resistors are well-known to everyone. They can be found everywhere in audio equipment, for example, in crossovers used in speakers ranging in price from $100 to $100,000. Externally, they all appear to be roughly the same. However, upon careful examination, it becomes apparent that they can vary significantly. Some of them exhibit substantial nonlinearity (several times higher than the nonlinearity of a good transistor amplifier), which is attributed to the physical properties of the wire alloy used to construct these resistors.
To test various resistors for linearity, I have assembled a setup according to the provided schematic, where the tested resistor is denoted as R_DUT.
As evident from the measurement results, certain SQP resistors introduce a significant amount of harmonics (distortion) into the test signal, and the spectrum of this distortion is dominated by odd harmonics, which are well-known to be the most unpleasant for the human ear.
Metal film resistors do not produce measurable distortion.
It can be observed that the amount of distortion produced by different SQP resistors also varies. Some SQP resistors generate minimal distortion. What is the reason for this?
I have discovered that high distortion is characteristic of resistors wound with wire made of an alloy containing a significant amount of magnetic material (most likely nickel). Conversely, resistors wound with non-magnetic or weakly magnetic wire do not introduce substantial distortion.
What type of wire is used in the crossover resistors of your new expensive speakers? You can verify this yourself using a powerful magnet.

So my brother-in-law bought a storage locker that was full of someone's stuff when they didn't pay their locker rental fee. He brought me a few boxes of amplifiers of various names such as DHD, Power Acoustic, Volfenhag, Crunch, Db Drive, etc. all bottom shelf stuff, nothing from the top shelf. I was wondering before i trash these things after taking the fet clamps out, are there any parts that I should think about keeping, removing from the board and testing for future use? I'm still learning the ropes so I'm open to any suggestions so bring it on. Thanks guys!

I hope this is ok to post here. If it is not I am sure someone will tell me!

This is not your typical component for sale. That is why I am posting it here. It is a DIY project.

This is for a pair of SIT 1s that are disassembled.

They have been replaced with THF51 amplifiers. I am too lazy to put these back together since I no longer need them. No squeaky wheel.

All of the stuff is here. There are three good SITs. The kind Mr. Pass sent me new circuit boards - they are not populated - along with two new power supply capacitor boards which are populated.

I had inserted LUNDAHL LL2733 for choke input supplies and when I removed those there was the idea I would return them to how they began. So many projects and they are still laying about waiting for someone to do something with them.

There are extra holes in the back panel since I brought the loudspeaker leads out so they and the speaker wires would be clamped by the whatever it is you call those things. Eventually I just soldered the wires since I am a connectorphobe.

There would be significant amount of work required to bring them back to life. Not that it would take weeks but it would be something for those who know their way around amplifiers.

I would like to get two thousand dollars for this mess. I think that is a fair price.

If there is any interest let me know.

Gain is like x5.
Distortion is not low: THD ~0.1%
This is the price you pay to get anything like tube sound.
Very low THD is not the way a sound of tube is like.

See the picture with Fourier Analysis. There is a lot of 2nd harmonic.
The rest of harmonics are very low.

The potentiometer is used to set the DC-offset.

Just an FYI that the Stereo has been available for a few days now.

In addition, in the Stereo page, is information on updating to the new firmware 1.2 along with downloads and new ASIO driver.

Note that the link for the firmware update is in the pdf on the procedure.

Hello,

I recently picked up a pair of Carver Amazings. They are in good shape with no ribbon buzzing. They have always been on my bucket list and really do sound amazing IMO. There are a few issues I want to address, one being to build a more robust crossover. I’m using two AB International 600As bridged, one of each one producting around 1k each. At high power levels the crossover gets quite hot and doesn’t smell good, LOL. I’m wanting to keep the xover values the same, but just able to handle more power and dissipate more heat.

My issue is in the factory service manual the value for L2 in the schematic is 25uH but in the parts list it’s 50uH. The component itself has no markings on it.

Does anyone here have any insight on the correct value?

Any help or insight would be greatly appreciated

Since i'm new to the forum Hello to everybody !
I have an old Harman/Kardon hk3470 with a 100Hz noise (yes i live in Europe) on the output with no music, just the speakers attached when it's daytime. When it's night time I don't hear it as much. I don't know what's causing it, but i'm sure after 20 years it should be recapped on the input stage at least. Also there is a 36mVDC at the left and a 6.2mVDC at the right channel, on the output when measuring (no load) with a multimeter (Voltcraft). Should i buy a new amplifier or can this be repaired somehow? When I bought it second hand 6 years ago, i had to do a little work on it since it didn't want to stay on, it constantly switched off. The problem was with a small capacitor hanging off the PCB, i also attached a bigger heat sink to one of the voltage regulators because it was burnin' hot, and also burned the PCB a little over the years. The weakest point i think is the transformer, because it becomes hot to the touch(>60℃ or 140℉) when it's on. Also here is the service manual attached if you wanted to look at it.

Hi there,

I realise this is a pretty basic question, but I'm not sure about it..

If the strength of the motor is the same (somewhat hypothetical of course), is it mainly the extra Mmd that stops a subwoofer driver from 'flapping', when used in a subwoofer system?
I'm considering trying to use the FaitalPro 12FX600 in a vented subwoofer box. It appears to straddle between a woofer and a subwoofer in its design. They have provided a frequency response curve with a 45 degree off-axis plot, which makes me think it's intended as a woofer, but then they do this even with their 18" subwoofers.

Obviously from experience I know that if you try to put too much bass through a woofer (presumably with a lower Mmd) they do start to flap eventually.

Perhaps the surround has an influence as well?

TIA

I have 2 brand new Sjostrom Audio QSXM3 Extreme Phono Preamp pcb boards available by Per-Anders. The design uses LT1028 (LT1115) along with an LT1010 buffer. An AD745 can be used in lieu of the LT1028 with some required cap and resistor value changes. MC & MM cartridge capable. These are bare boards and do not include any other parts or components. $75 each plus shipping. PayPal ok with added transaction fee. USA sale only.

PM me if interested.

Help. I'm new at a church as the sound guy, and they have an amazing sound system that is run by a tablet. The amplifier is actually on the stage with no cable runs back to where the soundboard is. I would like to use wireless headphones to be able to solo each microphone, but because there are no wires to send the audio signal from the headphone jack / control room jack back to where we sit to run everything, I have no way to hook the headphones up. I need a Bluetooth amplifier that will plug into the quarter inch jack and broadcast to headphones. Does anybody know of such a thing. All I can find are Bluetooth receivers to plug into microphone inputs. Thanks.

?

I hope this is a permitted post...

Is anyone interested in working on or expanding the capabilities of a 16 channel recording unit or just likes to tinker? I have some files for the PCB and some schematics and a build environment for the firmware. The owner of JamHub has asked me to open source the unit and will ship units to people interested in working on it (he has about 1500 of them that he does not want to put in a fill site). I believe if you are going to work on it, you can get them for free.

ixd704 (Ian Douglas) * GitHub has a number of files and descriptions of what I have done so far. I also have a working firmware image of 3.0.2 that can be installed to upgrade any of them that are running older fw versions. They all come with the telnet port active and the root password is in the Github description.

It would be fun to be able to remote control it via WiFi (it has an AP). Not sure what kind of work would be required to get it to transmit the channel data over USB to a computer system. The code for the menu control buttons is available and the processor appears to be able to do far more than it currently does.

Currently trying to make a port splitter so that the Tracker does not use up the remote port on the JamHub reducing the number of headphone remote mixers that can be used with it plugged in.

If you are interested, take a look at the github site. There is contact information on the site to get a tracker for experimenting with.

Ian