Hi All,

I'm having some trouble getting my brutefir setup working.

I'm planning on using the optical input and 8 analogue output channels of my X-Fi Titanium sound card for an active filtering system.

The thing is I have no idea how to map the inputs/outputs of the sound card to brutefir. The sound card is detected by the system and works. I can use speaker-test to generate audio output on the first two channels, the rest do not work.

Below is the output of aplay -l

I don't have any setup in my /etc/asound file, I have no idea how to do this. I haven't been able to find any documentation for it.

I have an analogue input and output on the sound card. I'm inputting 2kHz and getting nothing out. My current filter setup is a 1kHz high pass filter.

Any pointers or help would be much appreciated!

This is the output from brutefir when I start it.


These are the input outputs I have setup in .brutefir_config.

Hi guys,

need some help with 12 drivers please.

Some background:

I have a pair of JBL L112 from many years. When i obtained them they were not with the original 12" 128H drivers, but some other 22xx something and as they were rotten i send them to the garbage bin. It happened that at same time i had some new like vintage 12", no name, so i just dropped them in. They play surprisingly well, even feeded by 150W 8Ohm amp full power, not that i do that very often nowadays .
Meanwhile some other nice speakers passed here but at the end the JBL 112 stayed, i guess i find them perfect for me, sound, size, WAF
Now they are carefully placed in room and sound very nice.



So why to change the 12" then?

Mainly because i would like some more bass, which i am sure i am missing with these.
Then the 128H are not new, expensive to ship to Europe, very hard to find and who knows how they are reconed or repaired.
Apart from that i would like to learn DIy speaker design, at least a bit, cause i looked last 2 weeks at DIY speakers and honestly couldn't choose one to build. Due to high price of speakers >1000euro, or low power, or this or that.. Incredible. i looked at least at 200 designs. The speaker i would like to build would be like the Statements but 2x10" instead of 2x 8" or even better 1x or 2x 12" bass in a transmission line cabinet. This SUMMONER 1293SRTL is one i like, but they are in Australia, i am in Europe... If there was a kit combining the Statements with the Summoner ...

In other words i realise i am absolutely ignorant and will need a lot of time and first completing some projects before i make my dream speaker.

So its obvious i could at least play with what i have. plus just finished my 8x4 cnc so i am eager to "better" things around me.

The idea though is to start from things i love, i know and have idea what i want.

So my plan is some step by step side projects for fun, while learning, reading, learning to measure, etc:
-find suitable 12" driver for the JBL
-make a clone of the L112 and now that i have figured the bass driver, see how the other could be exchanged with better modern ones
-make a clone of the L150, which is essentially L112 in higher enclosure +
-make some other speakers, for example Statements, Sb240 or Vota 4.


So my speaker making journey started trying to find a suitable 12" driver, mean while learning what all these words and numbers mean.

Anyway, after countless hours of browsing i have narrowed to 2 drives, having in mind Fs ~20-22hz of the original 128H, coil size and travel, at least what i understand as a total noob.

- Monacor SPH-300KE , ~150 euro this one looks to me almost same same as the original, apart paper from kevlar, which does not bother me /now/

-DAYTON REFERENCE HF SUBWOOFER - 8 OHM - 12", more RMS, a bit less sensitive, ~200euro


I am attaching some documents for the enclosure, crossovers, etc.

Any help will be highly appreciated. And yes, i don't want to buy the original 128h and forget,i want to learn sth new and experiment



Meanwhile if sb has some idea on better tweeters and mids for the clone, without going too far from the original concept and sound signature of that speaker. For the future clone i mean.

What is the best approach to wiring the heaters on my amp? I have two 2A 6.3V outputs on the transformer and need to feed an ECC83 shared between the channels and two EL84 - one per channel.

I'm thinking one EL84 per output and then 12.6V centre tapped to the ECC83 with each side fed by the same output as its output tube.

Alternatively is it better to have both EL84 fed by one output and the ECC83 on the other?

Hi there mods,

Could you please have my account terminated / deleted? Thank you and best wishes to you all. Goodbye.

What would be your recommendations for how to integrate subs and mains in this scenario.

• Recommended crossover points.
• What to do about nodes etc? The peaks in the LF appear to be at 45, 80, 112, and 155 Hz.
• Do I knock those down with PEQ first, before applying the crossovers?

I have a miniDSP 2X4 HD

I have two REL Strata III subs, and a pair of Reference 3A Dulcet speakers:
6moons audio reviews: Reference 3A Dulcet

Subs are located 30 inches away, and 45 degrees behind and towards the center of each main. (See sketch)

Attached are a few measurements. I took three measurements and averaged them for the sake of this post. I used VAR smoothing, which seems to keep the LF pretty detailed, while smoothing the higher frequencies. Subs and mains measurements are taken raw, with no crossover or filters on the subs or in dsp. Obviously the blue is the sub and the purple are the mains. Subs are cranked up way too high obviously, but I can turn those down in software or with the dial. The question is about approach. Nothing is dialed in at all right now.

Hello i need some techical help, i dont have electronics background.
I have an old pcm1702 dac with the classic opamp iv and opamp buffer after.
If i want to use only the i/v part direct to rca bypassing the buffer, do i need a resistor in series with signal or a resistor to ground?

Right now i using an lt1028 as i/v opamp with i/v resistor and a parallel cap only from the output of the dac to the output of the opamp, and conneted the output direct to rca without any resistor in series or to ground.

Next i dont have preamp only have Amplifier with a 2.2uf input coupling capacitor.

Do i need any resistor in series or to ground from the iv opamp output to rca?

Tks.

Hi all

I've been intending to build myself a function generator, but spotted this on Ebay, from China. I couldn't buy the bits for that price! Anyone have one? Is it good?

VICTOR VC2002 Function Signal Generator 5 Digits (0.2 Hz ~ 2 MHz) 7 Frequency | eBay

Terry

Im looking for a pair of these in good shape ! Email me !

pryjo@hotmail.com

This amp came in with blown rectifier (U1620G). I installed a new one and the amp powers up and produces 70 volts rail and send clean DC to the output section but this power supply drive looks horrible.

Is this normal for these amps? It doesn’t look good to me. It looks like this all the way into the rectifiers but the rectifiers clean it up to straight DC. I’m wondering if this dirty looking power is putting undue stress on the rectifiers. If so, what could be causing this?

David

Hello,

I would like to add a music streamer & cd player by plugging a Raspberry Pi 2B in the AVAUX input of my old amplifier Kenwood A-91, via a DAC - probably an I2S one.
In particular, I am looking for a way to unify at least the power on/off function (others such as volume level or source selection would be great additions but I do not have much clues), and I see 3 potential ways of making the RPi interact with the amplifier:

1. 5V relay module: This would enable me to take control of the amp power from RPi GPIO ports. This is probably the best solution in the current state of my knowledge as it seems simple and well documented. I wonder whether such configuration would allow me to use confidently a plugin such as Amplifier Switch (for Volumio). It basically helps to save power by switching off automatically the amp when it detects that no music has been played in Volumio for X seconds (actually milliseconds), and switching it on when it detects that music is being played. Would the additional ON/OFF cycles caused by such feature jeopardise the life expectancy of my already old amp ? I see for instance that the relay I have linked to at the beginning of this point has a MTBF of 100k operations.

2. Kenwood "system control" interface: I also have the Kenwood radio tuner from the same product generation than the amp, and both devices can be linked via the Kenwood "system control" interface. It is actually a male 3,5mm jack to male 3,5mm jack connection, which enables that even when both devices are fed with independent sources of power, when you turn on/off the amp, it turns on/off the radio tuner. What's more, it enables the use of the few buttons dedicated to the tuner on the remote control, the IR receiver being located on the amp.
Linking the amp to the Rpi via this interface could be a neat option but:
a) I don't know how to interact with this proprietary (?) system control interface. I found this hint but I lack knowledge and experience to assess whether and how it could do the trick.
b) I am unsure whether it could allow me to control the amp power from the RPI (instead of the amp controlling the RPI power)

3. The amp includes two female power plug sockets (as per the manual they are supposed to supply up to 200W at 220V, although in my tests I experienced ) I could plug both the Pi & the DAC power supplies there, and when I would turn off the amp, it would turn off the RPi and the DAC. However the control would be from the amp only (less flexible than from the RPi to the amp, but still acceptable to me) and it would trigger a hard shutdown on the RPi which is not recommended as far as I understood (risk of OS data corruption).

Any answers or suggestions would be appreciated.
Best,
dtog

I have a DBX 200 program route selector which I am pretty much fed up with as it has dirty switches and I cleaned them once as best I can but it only helped some.

This explains what it does.

DBX 200 - Manual - Program Route Selector - HiFi Engine

What I want is to build a device that can replace it.

I need six stereo unbalanced inputs and six stereo unbalanced outputs.

I need it so that I can send any input to any output.

The connected devices are

Two USB sound cards
A reel to reel player/recorder.
An 8 track player/recorder
Two unused input/output positions which could be for future use.
The main inputs and outputs that connect to the tape out and tape in jacks of my preamp.

If I could get the switches cleaned good enough the existing device would work, but it is rather convoluted how the switching is done and each time I go to change a switch that isn't used much I have to fiddle around with the switches until I get them set in the right positions.

It's so convoluted how to do things with it that I cannot easily explain how to switch things for playback and record.

It is better than swapping cables around though.

Any ideas on how to build such a device to where only one input can go to one output while being able to feed any other input to an output.

An example is if I want to listen to my laptop while I'm recording a reel to reel tape to my desktop.

What I want is something straightforward and simple.

Flip a switch or turn a knob and an input goes to an output with some sort of protection so that multiple inputs cannot go to the same output.

Hi apologies if I break forum etiquette but its through ignorance as Im new to this.
A failed diode has blown out the transformer in my parasound P/LD 2000 pre-amp. There is no info on old unit. So was wondering if anyone out there has secondry winding info so I can get new transformer wound. Am planning to run 3 toroidal's 1for left 1for Right channel and a small other for ancillary circuit. Then fitting them all out-board with shielded umbilical.
So HELP anybody anything? stuck in isolation and no sounds Ahhhh.

I've been reading a ton about sealed subs, but the one thing that is never, EVER discussed, nor shown in the software (at least that I can find) is te efficiency of the final, resultant subwoofer. I guess this is because sealed subs are almost always used in home theater / music rooms and studio control rooms, so no one worries about having enough amperage.

I'm trying to figure out if I can make sealed 18"subs work in a live band / DJ situation, where efficiency is critical.
Note: I have actually already done this, for over ten years. The sound was lovely, but but the subs' inefficiency was a constant headache /nightmare:

I had been using four Bag End single 18's, with a single Lab Gruppen fp6400 driving them. With two subs on each side of the stage, I could do a medium sized wedding or rock club, but JUST barely. A high school dance was basically out of the question.

And I would constantly have to worry about tripping breakers. Those Labs were 1600 watts rms per side into each "two cabinet" 4 ohm load, and I owned THREE of these amps because I was constantly, literally, melting them & sending them off for repair.
Needless to say, I also got very good at reconing speakers. Literally several times per year, in-between gluing the surrounds.
-------------

So a few years ago I retired this system, and got a pair of QSC KW181's. I can't stand the bloody things. No definition, and no "integration" with the tops. This year I decided to try something else, but that's not working either. The problem is, anything small enough to carry by myself is a trade-off.

Before I go any further looking at custom ported builds, I thought maybe I'd revisit the sealed sub idea, which brings me to my actual question:
==========================================

I only need maybe 3 more dB than I had originally with the Bag Ends.
Could a larger cabinet get me there?

I have a pretty good grasp now on the pluses & minuses of a larger sealed cabinet. For me, not needing lots of bass extension, it's all gravy.
I can estimate that the Bag Ends, stock, have a Qtc in the neighborhood of 7.0. That means I have quiet a bit of leeway in enclosure size, assuming I will like the sound of a lower Qtc. I calculated enclosure size for a fairly similar 18" driver, with known T/S numbers, and got this:

Qtc 0.707 ~ 3 ft/3 F3 51.7 Hz. (Max flat amplitude)
Qtc 0.577 ~ 5.69 ft/3 F3 51.9 Hz. (Max flat delay)
Qtc 0.5 ~ 9.6 ft/3 F3 55 Hz (Critically damped)

The Bag End cabs are about 3.5 ft/3
A 5.69 ft/3 cabinet would work great, ergonomically, so I'd certainly consider trying this. (Using the old drivers, at least to start.)

EXCEPT: I can't figure out HOW TO CALCULATE THE EFFICIENCY OF THE FINAL, FINISHED SUBWOOFER!
For my application, I obviously need this critical number. The stock Bag Ends are 96 dB SPL @ 80 Hz (1W @ 1m)
If I doubled the enclosure size but only gained 1 dB at useful frequencies, then the experiment is a bust. - But an extra 3 dB at around 60 Hz would be incredible.

Is there a way to calculate this, if you know the efficiency of the raw driver?

And note: I'm only concerned with efficiency above 40 Hz.

Would like to aquire a HM130Z12. Anyone know where one or two new or used would be available?

Looking for line stage output transformers used/new in EUROPE.
10K:600R (4:1)
If you want to sell trade please let me know.

is it possible to install an output trigger on an amp? i installed a 12volt trigger on a behringer inuke to control my subs, i have 4 outputs on a monolith htp-1 but plan on running 6 amps. i see the output is rate 50ma on the monolith.
is it possible to add an output 12 volt trigger to daisy chain amps or will this overload the output on my processor?

I am having some difficulties measuring Vpp with my Rigol DS1054Z. According to the Sony service manual I have to adjust two pots so that it measures 6Vpp for H1 and H2 (after removing a bridge and feeding the circuit 1VDC).

Somehow I can't get a stable sine wave and the Vpp fluctuates. I am sure it's down to me not understanding all the features of the scope. Attached you will find the service manual instructions for the Sony.

Could anyone give me some tips to get a clearer steady wave form? Perhaps I need to reduce resolution or average the signal? Your help is much appreciated.

Hi,


about 10 years I bought a VTA kit (tubes4hifi) for the Dynaco ST70. Using the schematic I tried to build up an amp around this board.
Now, I finally had time to 'finish' it - however when engaging the high voltage I only get popping noises from the attached speakers which repeat about very second.
Also the bias voltage which should be adjusted to 0.4V is constantly alternating at around 1.5 to 2 V.

The problem is on both channels

I did not dare to let it run longer than a few seconds to half a minute... In the latter case i go smoke from in side the amp, or an EL34.


Is there a high risk to break anything? (I guess so.) And does anyone have a good idea where I should start looking for mistakes?


Thanks a lot!

On the bias adjustment section in step 4 it says to measure between 2 and E2 but there is no 2 and E2 anyware on the schematic above. What should. I measure? Also I don't have 8ohm loads as it requires should I run it with no load. For a while or connect it to my 6ohm speakers? Moreover in the warm up period do I need to have an input connected?

It's a rotel ra-840bx4. Here is the service manual ROTEL RA-840BX4 Service Manual download, schematics, eeprom, repair info for electronics experts

I am designing a buck-type output inductor for my smps, and the theory just gives me a headache..

The output current is 20A peak (coupled inductor with 10A in each winding) including the ripple current, and L=50uH. I want as little inductance drop due to saturation as possible (ok, as little as is sensible with an average current mode controller), and I want small physical size. This rules out anything not gapped? normal -26 material has dropped its inductance value by 10% already at H=15 oersteds, which is not many ampere turns for most cores.

I have begun looking at gapped E-cores of 3F3 material (the local shop sells this stuff with 0.35, 0.7 and 1.0mm total gaps), but I dont know what saturation phenomena I will experience in a gapped core. Will the inductance stay more or less the same as long as I dont exceed Bmax for the ferrite material?

Should I design the gapped ferrite inductor with peak B=0.3T in mind and ignore the amount of oersteds (H) I get, since I wont get the same drop in permeability with an air gap as I would get without the gap?

My calculations (however flawed they might be) give me that I need an ETD49 core with 1mm air gap to support 20A/50uH at B=0.33T, is this the smallest available for me?

With these practical problems in mind, is there any reason not to use a much lower output inductor value other than I will punish the output capacitor bank with much higher ripple current, and get the resulting higher output voltage ripple?

I pretty sure my laptop has just a few hours left on it and need a new one.
There are 100s to choose from but want to make sure the digital output is up to current standards, this laptop outputs at 96, maybe they are all the same idk.
A cd tray would be very handy also.

With so many to chose from not sure where to start.

Any thoughts?
Thanks!

Ok, I am still working on learning the basics of waveguide design from the many excellent posts here and around the web. Please bear with me.

Most horn/waveguide product descriptions include some variant of this phrase, provides good loading down to X Hz. I don't understand what this means. Should the HF driver not be used under that frequency? Should it be crossed at that frequency? Is it just a directivity change, and how does that impact the overall output shape?

To put this in some context, I'm intrigued by the new Celestion Axi2050 - the big heavy axiperiodic down to 300 Hz monster. The largest waveguides on PE provide loading down to 400-500 Hz. What happens if I put the Axi at the back of one of these waveguides? I mean just on its own without a speaker system around it, what happens? And how does that inform crossover design when it does go into a system? The spec sheet provides a response curve with a 30" horn so maybe I'm way off the path here and it's just not supposed to be used this way at all.

(P.S. To clarify, I am not planning a build. I'm playing with on-paper concepts to try and better understand how different systems might behave.)

Hi all.

First post after lurking for years... My office PC mini tube just died. It had been on almost continuously for a few years, but recently, due to these uncertain times, I turned it off and on a few times when leaving my office as I did not know when I could come back. When I came back to the office yesterday, I turned it on but only the power switch light came on, the tube remained cold and nothing of course came out of it.

It is a fairly rare version (APPJ PA0902A) with two 6J1 input tubes and two 6P1 power tubes. It always ran hot, including the transformers, but sound was alright--except for a strange intermittent 'crumpling paper' noise in one channel.

The fact that the tube heaters don't come on points to a failure of the switch-mode power supply (unless I am missing something).

So here are my questions:

1. Does anybody have a schematic for this amp? If it's just the power supply, It would be a waste to throw away the amplifier part with its transformers etc.

2. Is it a well-known failure mode and the power supply can be fixed? It is not-potted, so MOSFETs etc. are accessible.

3. If it is unrepairable, does anybody need these parts?

If anybody has suggestions, they would be welcome! Cheers.

--Christian

Is there a crossover filter plugin for vlc
on windows that works for 8 channel hdmi out?
Thanks,
WA

I have a Bryston 4b power amp. It is I believe the original one with square transformers. I had 300 ma of DC offset on the speaker terminals on one side. Saw that the power resistors looked overheated(which seems to be a common problem on these amps), so I decided to change them out along with the electrolytic caps. The amp sounded good, but eventually fried a tweeter before I decided to change these parts. I only did one side of the amp before testing it with a variac and a dim bulb tester. What is happening now is at 40 volt on variac everything is good, sounds good, as I turn up the variac the bulb begins to brighten at about 60 volts. I am hoping I can get some feedback from you guys as to what could be causing this current draw and what I should test or look for. The amp sounds the same as I turn up the variac. I tried he variac with the dim bulb on the other side and it does not light up. So there has to be an issue with the bad side of the amp.

I was working on my new push pull amp with 6SN7 || -> LL1660S -> EL34 x 2 The 1660S is configured as ALT-B (SE to PP out). When I looked at the scope this is what I saw. There is considerable ringing on the 1kHz square wave. This output is taken from the plate of the 6SN7. The 6SN7 is running off 200V B+ and 750R cathode resistor, bypassed. Substituting two green LEDs did not improve the output. Any thoughts or suggestions as why this is happening?

Hi guys im currently busy on a solar amp when the driver board is in the amp turns on then off again there is no output fets in but if i remove driver board it stays on no protection i tried removing driver ics still does the same

So...


I recently built a cinema-f20 with a Ultimax 15 driver and it sounds amazing. It plays down low to the teens, is very fast and has a lot of kick in the high bass range. This is something i want in my car.

I have an Alpine SWR-12D4 in a sub-small ported box. I don't know the exact specs of the box, but probably about 50-60 liters and tuned somewhere between 30 and 40hz. My amp is a Kicker DX1000.1. Stereo is a Pioneer DEH-x8500BT. Front speakers are a pair of Alpine SPR50. I plan on upgrading to some 6.5" components.

My car is a Volvo s80 2004. It is a sedan, so spl is harder to get than in a SUV. The s80 does have 8" speakers on the rear deck, but i want to replace those with aftermarket ones(recommendations in EU 0-150€?). It also has a ski-hole which I planned would be a great pass-through hole for bass.

What would be the best design to be used with the Alpine to get the most spl, lows and fastness? It is in a ported box now, but it doesn't have a good kick and is quite slow. A sealed box would be good, but the spl drops significantly. a horn-loaded box is what I've got in my room, but I've heard that they don't work well in cars.

I looked at the Decware Wicked one and thought about buying a second sub for that. But I've heard is isn't as good as advertised...
I don't really need trunk space, so I can use it all for as big a subwoofer box as possible. I've heard that something must always be sacrificed, spl, lows or space. That was the case with the cinema F-20. It is huge, but plays low and hits hard( and fast).

Especially the fastness is something I've come to liking very much. A ported box would be the way to go, but it is slow. How about a 4th order bandpass? I don't know how to design one though...

Would someone have any recommendations for how i design and make the box, or can someone design a box that would use the ski-hole in the s80?

During BAF 2008 Jack Hidley generously handed out some 6.5” Peerless NPT-11-078-1 drivers, the subwoofer used in the NHT Super Two and Super Sub loudspeakers. I brought some home with me and would like to use them in a project. I am asking for design ideas and am sure other people will be interested as several attendees took home the same driver.
On Jack Hidley’s personal page at http://home.comcast.net/~jhidley/ there is a link to an Excel spreadsheet containing T/S parameters and related information for this and other drivers. Here is what it says about the NPT-11-078-1.

Part # : npt-11-078-1
Used in NHT models : Super Sub Super 2
Brand : Peerless
Size : 6.5"
Shielded : No
Basket : Steel
Cone material : Laminated poly
Re (Ohms) : 4.84
Fs (Hz) : 51.7
Qms : 2.738
Qes: 0.584
Qts: 0.481
Vas (l): 16.10
Cms (m/N): 0.000543
Mms (g): 17.4
Diameter (mm): 136
BL (N/A): 6.85
SPL (2.83V): 87.64
Zmax (Ohms): 27.6
Sd (m^2): 0.01453
Xmax (mm): 4.9
Hg (mm): 6.0
Hvc (mm): 15.7
Former material : Aluminum
# of coil layers : 2
Coil diameter (mm) : 32

Hello,

I own a Schiit Lyr, that I don't use much and I was evaluating if I could use it as a low-cost amplifier for a couple of high efficiency 16Ohm/ch speaker.

This is my reasoning behind it:
The amp max power is rated 6.0 Wrms/channel @32 ohms.
Ohm's law tells me that 6Wrm@32Ohm corresponds to 13.9Vrms x 0.433Arms, which means I can safely draw from the ampifier output at least 0.433Arms/ch without sending its output stage in thermal runaway.

Let say I connect the 16Ohm/ch speakers, and protect the output stage with a 0.4A fuse, I should be able to 2.56W of pure class A per channel.

The output impedance of the LYR2 is 2.6Ohm, so I won't expect the damping factor to be that great, but considering I am gonna be driving very lightweight drivers that shouldn't be horrible.

Anything I forgot to consider?

hi everyone,
I've been reading this forum for a long time but this is my first request...
I have made a half bridge class d amp not self oscillating, based on a 16MHz crystal and 4060.
the triangle wave is 700mV pp @ 250 Khz
the input opamp is TL072 (supply +-10V)
LM 319 comparator feeding a level shifter common base transistor

the next stage is 4070 and IR2113 to the N cannel Fet IRFP4227...
54uH and 470nF LC filter
post filter feedback

Power supply is +-80V 1kVA
IR2113 4070 are biased 12V over -80V

First power on no problem sound was great deep bass high frequencies clear but when i pushed it to clipping (symmetric at least !)

1 min after the 2 fet and IR2113 blow up

cooling was sufficient.

I don't know what happened please help...

Fets are not cheap and IR2113 blow every time fet do...

This circuit dont use feedback, have 3,5 ohm of input impedance, and very low distortion , it gave only 0.000005% of distortion in the LTspice simulator at 2,5Vrms.


Yesterday, come to the conclusion that i need a new dac, so i will use the pcm1794 and dir9001, just because already have them.
I dont like the I/V of the pcm1794 datasheet, so i remember to use a circuit that i have design for a non feedback amp.

in attachment there is the asc file for the simulation. dont forget to go to control panel / compression , and turn off all compression for better visualization of fft.

if you have any doubt please fell free to ask 🙂

Hi

17y ago I biased in class A my op amps and was very happy with the sonic result. I used a trim pot and found the best sonic result for these to be at 2.4mA. So back then I biased the AD825 with one resistor and one 2SK170. OK, back then AD825s were very expensive and 2SK170s not !

I want to do exactly that again, still with AD825, but obviously the situation has changed. I have many AD825 handy, but no one would want to waist SK170s on that.

Could someone please point me in the right direction to get a suitable transistor replacement, non expensive and easy to get from Mouser, if possible leg / pinout compatible, and of course the associated resistor value so I get 2.4mA (under 15V) ? Having the right resistor value would help me ordering all the parts in one go, part of a bulk purchase at Mouser’s…

In short exactly the same but transposed in today’s world « avoiding the use of SK170 🙂

Many thanks for your kind help

Claude

Just a general question:

What is the subjective difference in sound quality between a BIB and a tapered transmission line? I know physical size is different... the tapered transmission line is smaller.

Both with the vent? out of the top.

HiFi Loudspeaker Design

vs

BIB - Speaker Projects

They look similar in construction... just the position of the driver relative to the closed end and the direction of taper is different.

Thanks! Forgive me if this is basic... just trying to understand the differences.

Just finished building my rotary subwoofer and it works quite well. One problem is however that it generates excessive wind noise which I would like to try to eliminate. I've heard one suggestion that includes building some form of baffle system that will absorb high frequencies manually well passing the very low frequencies that are being generated by the rotary sub .more or less a manual low pass filter. Can anyone share how this would be designed. Thanks

As the title suggest I am looking to replace the Vifa P13WH-00-08 drivers that are currently being used in the studio. Ive put great amounts of effort into searching around in different shops and forums for these exact ones, but with no luck. My coworker has grown quite a relationship with these drivers over the years so it would surely float my boat if anyone here is willing to share the knowledge they may have about close to identical drivers

Hi All

I have a Rotel RA-870BX which is having problems with one of the channels. Iv'e had to put it out of commission and go back to my old RA-820AX for the time being and my Tannoy 611's are not really breathing properly hehe.

Are there any service engineers / shops / forum members who would be able to help servicing the unit and possibly upgrading it, maybe replacing the old capacitors etc. I'm located in South Yorkshire.

Thanks in advance.

🙂

What would cause there to be a space between the 2 squarewaves like shown in the pic?

Hi everyone,


Last year, I've started to built an archive website regarding the Onken company which I really like. The site is in French, but you will find plenty or articles in Japanese and French, pictures, catalog, etc...



Here's the link:


Onken




I hope it can be of interest for some of you,

Sébastien

Hi bought this amp last year and it had been messed with badly 😱
didnt work and had been fully recapped before i got my hands on it
replaced the regulators for the volume chip and got it back to as original as possible now working
the 6 bypass caps per channel have been added by whoever modded it in the first place
whats your thoughts ?
should i keep them or remove ?
Also if anyone can supply a schematic would be very grateful ?

20190724_132943 by glenn jarrett, on Flickr
20190729_135336 by glenn jarrett, on Flickr

I have JBL SLR305 monitors which always pickup pops when AC, fridge or dishwasher turns on/off. A loud pop. Nothing else or any other transformer based amps I have do this so I put it down to a cheaply made switching power supply in those JBLs which picks up noise from power line. I tried different sockets around the room, extended cord to other room but nothing has any effect.
Is there anything I can do apart from getting isolation transformer? Some years ego I had one which I used to eliminate ground loops but it was always buzzing when it was on which was really annoying in the room.
I read people talking about ferrite ring on power cord but I'm not too sure if that could do anything at all for mains power, possibly just a snake oil.

Just got a Martin Logan Voyage to use as a centre speaker (https://www.martinlogan.com/uploads/documents/manuals/manual_voyage.pdf).

But, I don't want it in the wall (as the TV is currently on a stand), so I'm building a box for it until we get the next TV. And, even then, I'm just going to build a thin box to sit below the TV so I get to use nice panels instead of sheet-rock.
The guys at ML provided a spreadsheet for sealed box design, and their thinking is that a standard in-wall mount (between studs) would provide about 75 litres (2800 cubic inches) of space.
So, no problem.

I was just wondering if anyone had the specs for the 8" aluminum drivers that they use? In case I wanted to port the final enclosure, or use a passive radiator, or even open baffle it. Mainly for interest. But it does appear that a much larger box would provide less of a peak in the midbass compared to the standard install.

Hi all,

I am desperately looking for a replacement board for a Candeias Modelo CD transport. It is from Sanyo and must have been part of their own CD players. The pickup is an SF-90.

Furthermore, it would be great if someone knows where to find more information on the Candeias CD transport. Unfortunately, one of the previous owners tinkered with it. A picture of the inside would help, at least.

Cheers

Marc

Does anyone have SPICE models for 2SK209 and 2SJ106 JFETs?

Please help me to find the V & A of attached photo diode.

TIA

Hi Everybody,

In a 2.1 setup, is it necessary to put the high-pass filter on main speaker? Can I connect main speaker to full-range output of the subwoofer(active)? What is the advantage and disadvantage of doing like this? Thanks in advance

I need to replace a surface mount ic in my amp and the markings are LM393 which the data sheet says it’s a dual differential comparator.
now it seems like there are a ton of difference ones LM393, LM393DR, LM393D, LM393P, LM393N……etc the ic just says a LM393 Is there any difference?
Cheers

Hello,
Want to build a simple amplifier with 6p21s(DHT) at power stage and 6n2p (non DHT) at préamplificateur stage.
Filement voltage is 6,3v for both.
Want to use the same power suply (Regulated with a transformer),same circuit for these both kind of tube .
Is it possible ?
What the disadvantages?
Any review ?
Please
Regards

View attachment Frequency Response-plot.pdf

I have Dynaudio 17W75XL {pn#84862}8 ohm mid/woofers from Dynaudio BM6A studio monitors [put into in 12 litre vented enclosure] and D260's tweeters out of Vision Acoustique model 702 speakers. I have worked hard on a very nice-damped/braced cabinet for these drive units. I now need optimum crossover design for this combination with high/low pass sections, respective zobels for woofer and tweeter (if recommended), maybe resonant or notch filters to improve sound and tweeter attenuation if necessary plus any phase corrections, etc. that might also help sound quality. Currently I have below configuration crossover that sounds good already and will rebuild crossovers a final time to live with the speakers forever upon getting proven ideal x-over spec and finally put this fun project to bed. Had based initial crossover design with attached theoretical plot with online "Speaker Wizard.uk" resource. Using Solen standard air core coils and polypropylene caps now but will consider Solen litz coils and Solen film/foil caps next time for final crossover build. Also using Solen achrohmic mil-spec resistors. Love the Dynaudio sound so far...!!!

Thanks in advance for any help!,
Gordon Hunsaker
Calgary, Canada

Please disable my account as I managed to misspell my six character UserID. Should be ralphj and not talphj. Thanks.

Hi all! I just joined the site as I'm getting ready to build some vented enclosures for a pair of JBL D140s I have laying around.

But my first post have nothing to do with that. I was listening to some Allman Brothers Band while working my day job from home and I noticed a strange piece of equipment behind Gregg Allman at 10:50 that I can't identify.

Anyone here know what it is?

YouTube

Hi all

I have this amp for repair with a blown psu, it has 100ohm gate resistors with IRF3205 mosfets, is this correct?

Spurred by some threads about loudspeaker break-in or the lack thereof (and let's please NOT get into debating that here), I'm interested in doing some experiments for that. Which means I need to be able to measure resonance at a minimum, and all the parameters ideally. However at home now I don't have any equipment to do so*
--> What are some hopefully good and definitely inexpensive ways to do this?
I know the parameters change depending on how they are measured (for instance constant voltage vs. constant current) and versus drive level. I don't care about that too much, just something consistent.


*OK I could get a series resistor and probably generate a tone via smartphone and measure the voltage with my voltmeter Hertz by Hertz...😱

hi... been easily 10 years disconnected from playing with cars in general, recently retired in sunny thailand and would love to go back to tinkering and doing stuff with audio. Now it's not like all brands are available here when compared to the UK... but there are a few

I'm so lost hah. I ofc know all the OGs from the 70s onwards but some of them are now chinese owned? A/D/S used to be the **** now not so sure according to some sources.

I was looking on the pinned threads but theyre all 2011 and so on... googled car audio brands only some forums with also older info and this Top 10 Car Audio System Brands – Expert Review Blog monstruous list I haven't fully gone through yet.. I definitely don't know like... 50% of the brands on it..

I used to run the "posh" stuff, morel, focal etc... seems like those guys have kept their quality up though.

thanks for the tips

TM.

Loud popping noise with Classe Audio SIX pre-amp in phono MC mode


Loud popping noise with SIX pre amp in Phono MC mode.
Hello ,
I´m a proud owner of 2 very nice classe audio amplifiers.I have a Classe Six pre amp and a sevenhundred power amp.Both are very nice sounding, very musically amplifiers.I use it with Infinty Delta/Gamma speakers and sometimes with my good old Infinty Quantum 3`s.The TT is a LINN LP 12 with Lingo ,Manticore Magician arm and an Ortofon Jubille cartridge.Since last saturday I have a problem as follows:sometimes when I raise(or better when i touch) the Volume at the pre amp there comes a loud popping noise. The amp is going into protection mode (The red LED stays on continuesly) and comes back after a few seconds with light popping noise(DC at the preamp outputs around 180mV) .After a while it dissapears and everything is working fine.Maybe some forum members knows the problem or ad similar experiences with his pre amp.Maybe there´s something wrong with the phone stage?
I am thankful for every help I can get
with best regards

Hi.

I am building an amplifier with WE 350 Beam Tetrode.

I have a dude.

In the datasheet , i can see , 16W output power with 18% of distortion , and 11 W output power with 10% of distortion. I think tetrode mode.

Can anyone imagine how many watts of that 16W or 11W could be used for audio.
In ultralinear mode could you lower the distortion ?

Santiago

I have some sweet MDF taking up space in my garage. I have some nice 1-1/8" panels that are 12" x 48" and plenty of 3/4".

Since I'm stuck at home anyway, I'm looking to fab some nice things. I don't need speakers. Not even sure if I'll get my money back if I sell them, but ever since I built my own C-notes last year I kinda have the bug.

Possibilities:
- Powered studio monitors since I am setting up a home studio
- tapped horn to stash under the couch for vibrating my butt when I watch a movie. My existing sub is surprisingly good down to about 25hz, so maybe something tuned to 20-ish to pick up some sub-sonic stuff?
- live performance monitors (powered or not)
- live performance loudspeakers for small venues (think like StagePass size, easily portable for jazz duo in a restaurant or guitar in a coffee shop.)

I'm doing a design process (for myself) that starts at the desired application, choosing the enclosure type, delimiting the max dimensions and setting targets for the resonant frequency and the loudness.

Then I'll set targets for the T/S parameters and build a subwoofer with them in mind, so the obtained parameters will allow me to design an enclosure with the profile I want.

Noting that there are more limitations in respect to the driver: I have a chassis, two magnets and just a few options for the other parts; so I'll be mostly doing coarse estimates to choose the best combination.

But I'm affraid the Qms maybe too hard to estimate.

Without assembling everything I can use a weak glue or even tape to attach cones and spiders, place them in the chassis and estimate the Q factor by adding weights and analyzing the oscillation.

But I'm afraid that value is very different from the one I'll get after being properly assembled, because when assembled the resistance caused by having to force air around the coil increases dampening a lot.

Do you think the change in the Q factor due to this one factor is enough that even coarse estimates may fail?

Thanks!

Hello,

I have two questions one that is about subwoofers and another is about amplifiers. Let's get in to the detail about subwoofers and crossovers. I want to make sure that I'm thinking right. Here is two scenarios:
1) Subwoofer has a "Low Pass" filter at 150Hz;
2) Subwoofer has a "High Pass" filter at 30Hz;
I have statements that i want to make sure they are correct. First scenario with a "Low Pass" filter keeps the subwoofers voice coil from overheating. And second scenario with "High Pass" filter keeps subwoofer out of uncontrolled (depends on the enclosure) Xmax. Are they true if the power of amplifiers is constant in both cases and it's not higher than the recommended?


Another question that I'm concerned is about amplifier power and how it powers subwoofer. Let's say I have a way to measure amplifier power at 50Hz. I measure it and for example I choose to power my subwoofer @ 150wRms (in this case 20V). Everything that is below 50Hz will get less power and everything that is higher then 50Hz will get move power. Is this statement true?

Amp powers up but no output .

Checked rail and regulated voltages and amp is producing both .

Any ideas where to start ?

For the last nearly 20 years I have dreamed about building an SET tube amp. It started in highschool, where I drooled over kits that I could buy and simply just build from detailed instructions since I had no electrical/electronics experience. I did build a Forepay pre right out of highschool, which I enjoyed building and listening to for years. I looked forward to building a 2A3 SET amp to mate it with. Of course relationships got in the way of funding, then marriage, kids, etc, etc...

Anyhow, I said “now or never. It is time to build something!” After searching around I came across Hagerman’s write up and thought this is excellent! there is a schematic, a parts list with part numbers, general information, I can do this. I ordered the small parts like sockets, plug, fuse holder, binding posts, inputs, etc., to lay it all out on the chassis. I liked how the amp was designed from parts that were accessible from one single supplier, however this meant being locked into those prices. Like many others, I’m sure, I am on a “budget” there is no cap per say, but I can’t set the wife alert off... I decided to go ahead and order the transformers through Edcor regardless of the bizarre 8 week build time.

The Hagerman Clarion Article

Fast forward to now: I received my Edcor high and low voltage and output transformer on Saturday. I am pleased I went that route, these helped my “budget” and will also look good. FYI their site says 8 weeks, but I received them in about 3.

As of today the chassis is mostly machined, I am drilling/machining it as the actual parts come in to ensure proper fitment. I will find a way to post up some photos soon. The only things left to machine are the power switch, volume pots, the necessary lamps, and mounting the chokes inside the chassis. That all is the easy part for me. The hard part, for me, is yet to come.

I started inquiring on the post Hagtech Clarion 2A3 SET I felt it would be better suited for me to start a thread of my own, for my own build. Where I can ask around for advice on my particular build instead of a 11 year old treat that has been silent since 2015

That is my back story, I hope some of you are willing and able to help me out along the way to complete this project of mine.

If I have GZ34 rectifier and 450V filter capacitors is it allowable to have AC voltage at GZ34 anodes with peak value above 450V?
I already have transformer with 2x 310V rms winding for GZ34, so peak AC is less than 450V. However, GZ34 is indirectly heated so when it start to conduct current other tubes will also start to conduct which means GZ34 is never operating without load so voltage on capacitors cannot reach peak AC (unless all other tubes are plugged out).
What do you think, is it possible to slightly raise AC voltage at GZ34 anodes to say 350V, would it be safe to still have 450V filter capacitors?

Hi,
I have a small pair of PP 12k about 10w electra-print OTs. I would like to build a screen drive amp with them. Any ideas for a good design or schematic?

Thanks
Chris

Hello!

I've had some success adding speed control pots and aux inputs to small dictaphones but I've recently got myself a reel to reel and I would love to add a few things to it. Problem is I'm a lot less sure with how to approach this and not break the machine, the internals look a lot more intimidating plus it's 220V here so I would really appreciate if anyone could offer some guidance?

Essentially I would like to do 3 mods:

- speed control

- reverse switch

- erase head switch



I'm not adept at electronics by any means but I'd assume the speed pot would have to be a 100k potentiometer wired to the motor or the motor controller?

To reverse the polarity of the motor I have a DPDT switch but I'm not sure where should I wire it to (the motor on this is 4-pole).

I'm also aware that disabling erase head will mess with the bias unless you switch it to a resistor of same impedance, question here is what impedance would it have to be and where would I wire it?



Thank you in advance for any help, I would really appreciate it!



Here's a service manual for TK-14, I assume it's very similar to the 14L (only one I managed to find).

WeTransfer

Hi, Im not getting any sound from my alpine mrp-m1000 amp. I bought this second hand around 4 months ago, tested it when I got it, fitted it to my car last week and had it working for about 2 hours in total over a few short journeys, then nothing. power light comes on and i can hear very quiet clicking sound from both subs.
I'm running 2x alpine swr 1242r subs (came with the amp)
I have checked all connections, tested rca leads, checked the total resistance of both subs which come to 4ohm at the amp terminals.
got good battery voltage, good earth and good remote.

Removed the amp from my car and took off the rear cover, havent tested anything inside yet as I'm new to this but I noticed one of the transistors seems to have got hot as the legs have a darkish tint to them compared to the rest (position Q4901, part number KDY 600K), the circuit board has a slight burnt smell too.

On looking in this forum it seems that a few people have had very similar problems but i'm not sure if they have managed to fix their amps as no-one has said it worked or not.

Has anyone got a service manual for this amp so I can possibly carry out some tests and get an idea of the figures I should expect to see? I may then be able to locate the failed part or parts and fix it before sending it to a repair centre.

My email address is dan66turner@yahoo.co.uk

look forward to any replies. thanks.

Hi all

Ive had my tu8600 for two years and just today i noticed that an issue has developed.

For background - I use the amp as a permanent amp for my speakers, but occasionally plug in headphones.

The issue:
When the amp is on (but volume is turned down to zero) and i plugged in headphones today - i heard a crackle in the left channel during the action of plugging it in. Similarly, when i unplugged the headphones (with volume turned all the way down), i heard a loud pop/crackle from my speakers (again left channel). I haven't experienced this until today.

However, the amp works and sounds fine when in operation and playing through speakers, or playing through headphones where i turn the amp off before plugging in the headphones, and turn the amp off when unplugging.

Just wondering what parts might be at fault in order to fix the amp.

Many thanks for any assistance

Hi.

In these Corona-times I have some time to work on this amp, but I have got myself a headache trying to understand what's going on.
The amp goes in protection, so I have to start it in self diagnosis.

There's 1v8 DC on Surround back right output.
I have pulled both OP-transistors and they measure OK. I have also measured the rest of the semis in circuit and compared them to the other channels.
Of course there are differences, but not more than expected, typical 0v552 - 0v562 drop or so.

Maybe the fault are located in the stage before the OPS ?

The amp are not easy to start up without Yamaha's extension cables, and one can't measure on OPS when the amp is assembled.
So maybe someone have a good clue about what is going on.

BR

Figge

Hi,

Just got a Heathkit IP-17 power supply.





I will use it to put together small "flea power" tubes amps for fun, tear them down and put together another one with a different small type of tube, etc...


Now on the Heathkit power supply, on the front, there is the + and "common" high voltage outlets for the amp circuit.

Also there is a Ground one by itself, should I tie the ground to the "common" outlet of the heathkit?

Since the "breadboard" will be an old tube amp chassis, should I use the Heathkit ground for the chassis ground?
I dont mind soldering and unsolderings the parts on the chassis and using it as the negative/ground of the circuit. Would be more solidly tied together since I might listen to the test amp for a while on 2 sets of speaker in two different rooms.
Also, I might fool around with some preamp circuit.

So in fact, my "experiment" circuit would be: the B+ , and the chassis on the negative/ground from the Heathkit.

Should I install a fuse on that chassis?

Just like a normal tube amp.

But then, if the Heathkit only has a two prongs AC plug for the 120 Volt from the main (didn't received it yet). Should I install a 3 prong AC plug?


Kind of funny, but I love to fool around with tubes amps, but I'm pretty scare of these high voltages, hence all these questions...
What would be the best way to go about it.

Any suggestions, ideas, objections?

P.S. I already built/restored a few Tube amps: 300B SE. Dynaco ST-70, ST-35, TubelabSSE, restored a Fisher 500C and a pair of QuadII.

Search the forum for this, didn't find much.


Type of circuit I'm looking at:

My Superphon Revelation Dual Mono has developed a loud buzz in one channel, audible both line level inputs and louder on phono input.

Some background: I was testing some speakers and moved the speaker wires and interconnects during testing (preamp was muted at the time)
After this, the preamp immediately had a loud buzz in the right channel.
Signal is still present on the channel with the buzz.

This preamp is dual mono all the way to the (single) transformer. I've replaced the electrolytics last year (exept for the 4 largest ones in the power supply) and it's been working very well. I've checked for cold solder joints, but see none, the preamp was not moved/dropped etc.

I have an EE degree but have done little circuit level debugging since graduation 12 years ago (more of a software-related job). I do have a scope, DMM, L/C and ESR meters, etc.

So far I have tried isolating any bad components by tapping with a wooden stick but can detect no change in the sound when doing so. The parts count is very low in this unit, so I pretty much tried the tap test on everything. The large 1000 uF electrolytics in the PS are 25 years old but show no sign of leakage.

Can anybody think of anything that I can check? Where would you look first?

The schematic for the preamp is at http://www.diyaudio.com/forums/gallery/uploads/78563/Superphon_Rev_schematic.jpg.

I appreciate any suggestions you might have.

This is nothing to do with a build thread.

Anybody know of a subjective level chart for bass decibels?
I know loudness charts exists but they are mainly for high frequency sounds.
For instance 85dB in the highs might cause a slightly achey ear over time (think of a loud-ish bar with lots of conversation or a cranked TV set, or turning the stereo up a bit to do the vacuuming, or jamming with headphones at a "fairly loud" level) but 85dB of bass you could probably talk over. The level of bass rumble in a moving car is probably this much (assuming you don't have one of those really quiet posh cars)

I heard 105 dB of bass in a corner of a club in Coventry which sounded pleasing but not "loud". E.g. having free reign of a volume control and no one else wanting it quieter I would probably crank bass louder on my favourite tunes at home. Probably enough to go with the 85dB type level I mentioned above. The music was pleasant to dance to all night - not the fill your head with noise level and I want to leave and go to the bar after half a song and I have to shout as loud as I can to have a conversation level.

What level does "ear poppin'" bass happen? I've been assuming the level you can start to feel bass in your ears (as if going through a train tunnel, or the feeling you get closing the last door in a car) is in the mid 120s but I could be wrong (it also depends on the person's ears). I've got an SPL meter but it only does dBC and would probably pee off the neighbours during lockdown trying to test this. (Unless I can build a subwoofer cab I wear on my head with the mic inside it)

Ear tickling is around 120 apparently for strictly mids and highs (dBA), and 115 is about the level which goes right through you (think obnoxiously loud rock concert vocals you can feel tightening in your skull, or someone wanging a snare drum from a meter or two away).

Though if some of these enormous car stereos are hitting over 160 dB of bass within the confined space the woofers are used. If "ear poppin'" bass happens at say 130 and loudness doubles every 10dB then how are people sitting in cars subjectively 8 x the bass loudness you can feel in your ears? I mean imagine one of those old school receivers with the big dial from "0" to "10" and on "1" the bass is loud enough to feel funny in your ears and you still crank it to "10"! They don't seem to have earplugs in, or are they tightening the ears manually with muscles, or just stupid.

But saying "a Jet engine is 160dB" is meaningless because jet engines have unbearable squealing highs at 160 decibels (again imagine the big old school receiver where "0.5" is a really loud rock concert and between "1" and "2" is someone shouting into your ear and it's cranked to "10")

The one time I've heard "unbearable bass" was when I built an Autotuba and was testing for leaks inside the horn mouth. I put a plastic tube in the horn mouth and the other end in my ear but when I turned up the test tone, the bass travelled down the tube and was making my ear feel tickly. I took the tube out and could feel the movement of the air with my finger. It wasn't a good way to find leaks - only on the outside of the cab. Another is sticking my head in a Funktion one folded horn, you could feel bass in your ears as pressure and the kick felt like someone hitting you lightly in the head with the palm of the hand!

It's just people post of subwoofers doing 130 dB or whatever at 1 metre and I'm not sure how loud this is supposedly in the real world subjectively unless I can find a big open space to blare subwoofers.

For instance a Danley TH812 subwoofer can produce 148 dB at 1m, I assume this to be very loud but saying something like "this subwoofer produces a blocked ear feeling at 10 metres away" would give a bit of a real world though highly subjective indication.

I know this comment isn't very objective, but a subjective loudness chart for bass only (Frequencies from 25 to 75 Hz) would be useful.

I've been working on a Mini Aleph build over the last month or so and wanted to share my progress here to get feedback and also to hopefully provide some helpful information for future builders. And to be fair I should mention that the "last month or so" actually refers to the following build schedule:

2007 - Bought a LM3886 kit from Chipamp.com and on a whim added some Aleph boards to the order.

2008? - Placed an order with ApexJr for some other parts and remembered the Aleph boards so I added some transformers to the order.

2009? - I was moving and didn't want to move my 12" sonosub so I traded it to another DiyAudio member for some capacitors and heat sinks for the Alephs. In a major coincidence Variac was going by that person's house and offered to drop off the sub for me and pick up the parts. We then both forgot about them for a year or two and they sat collecting dust at his house.

2011 - At Burning Amp Variac and I talked and remembered the Aleph parts, but weren't sure where they were hiding. I had written them off as donated to another project, but a few months later they appeared at my office. Variac kindly included some large aluminum C-channel for the amp enclosures.

February 2012 - Over four years after I bought the Aleph boards I purchased the rest of the parts and started the build.


At some point I'll try to get around to doing a full writeup, but for now here is an overview of the build and some photos.

- The Aleph boards and the two power supply boards are from Chipamp.com. Using separate power supplies for a 10-15w amp is probably overkill, but since the transformers were $8 and I had the capacitors I figured why not.

- Matched Transistors (Q1/Q2) were purchased from tech-diy.com.

- Transformers are Signal BL1752 from ApexJr. Primary 230V -> Secondary 48VCT 7A & 28VCT 3A. Primary 115V -> Secondary 24VCT & 14VCT. I'll be running these at 115V and using the 24VCT secondaries which should hopefully give me 14-16v rails. For now I am not using the resistors in the CRC on the power supply boards, I may add those later after measuring the ripple.

- The rest of the components were purchased at Digikey or ApexJr. One great thing about Digikey is that you can add customer notes to your BOM which are printed on the labels, this makes things really easy when you are doing the build since you don't have to lookup which part is which.

- The most difficult part of this project has been figuring out how to get power from the power supply unit to the amp. I needed a 7 pin plug, but I didn't want to spend a ton of money. The plan is to use a 7 pin aircraft connector ($8 on ebay), though I have concerns that the pins will be too small for the 14g wire I'm using, we'll find out.

- I'm targeting a bias current of 1.2-1.4A since I will be using this amp to drive 4 ohm speakers, and because I have the heatsink capacity. For now the amps are built using fixed value resistors, but I have some precision trim pots I can substitute for R13 to adjust the bias.


That's all of the pertinent information I can think of at the moment. Please feel free to post questions, comments, suggestions, etc. I'm really looking forward to firing these up to see how they sound.

Why is this driver not more used? Seems superb:

- Can be crossed at 1 Khz
- Better vertical dispersion than traditional ribbons
- 98 db sensitivity
- Super clean waterfall
- Excellent extension

Only downside I see is the price.
Or am I missing something here?

As the title says, I would like to buy RS1026 tubes to make some experiments.

Thank you

We’ve kinda been off topic with this stuff on the other dac threads so figured moving it would be a good idea?

Good morning DIY audio peoples it's been awhile since I've been on here and have a new project. Have MTX ta 92001 that has output but the LED lights on the top of the unit are not lighting up. the output is very distorted and staticy the first initial base hit of the music note played good, every note after that tends to wash out and sounds very staticky as if it's losing power open up the unit. The little corrosion by the large capacitors by the output terminals . also the two large inductors by the power input or buzzing really loud. LED light behind the RCA inputs are not lit up but the LED light by the output inductors top left corner are on. what do y'all think about issue might be? or where to start, the and work perfectly fine before the winter has been stored out in the garage in the Chicago weather for the winter time now this issue is present.
thanks.

MR Lundahl We know why there is a shortage of toilet paper
@lundahltransformers

Mysterious toilet paper shortage explained. Since the recent invention of the paper wound transformer, transformer manufactures worldwide have bought large quantities of toilet paper from local grocery stores. Unfortunately from what we have heard, the new invention has resulted in panic among people with more traditional toilet paper habits.

This is a 4 channel amp, 500 wpc into 4 ohms, or bridgeable to double the output into 2 channels. Never been used and still in its box. RRP is £311, I’m asking £210.