Hi All,

I have a Bottlehead Smash that I built a few years ago. I want to remove the balance pot and instead use separate L/R volume pots. The schematic for the input/volume/balance portion of the circuit is attached. In my simplistic way of thinking, I can just take out the balance pot and wire in separate volume pots, but would 100K volume pots still be correct? And do I still need the 33K resistor? Just not fully understanding the interplay between the volume pot and balance pot.

SOLD
This is a pair that I bought from this forum about a decade ago and they are $280 new now.
I used them for a few years but have since repurposed the cabinet. Still come with original measurement graphs and original box, but one tweeter has some soldering iron marks at the back, as seen in pic.
Asking $80 due to age. Can't beat these if you need high dispersion.

Looking for opinions from people who have built or heard them both.

The CCDA is like an "Aikido light" with 1/2 the tube set. It also inverts.

Thanks.

As the title states, looking for 4 6h23neh tubes for my audible illusions preamp.

Please let me know prices and shipping.

Thanks!

Hi, I am trying to gauge the manner in which the Threshold S/500 operates in Class A mode given the impedance characteristics of a pair of Sound Labs.

Would someone assist with information on how the S/500 operates in Class A at an impedance other than the nominal 8 ohm rating, for instance a 1 or 2 ohm load. It seems the amplifier operates in Class A up to 20% of its nominal power rating(250 Watts into an 8 ohm load).

Apparently some if not most Class A functioning amplifiers exhibit a phenomenon called "de-rating," whereby there's a reduction in Class A power at lower impedance(Exceptions to this phenomenon comprising the likes of the Pass Aleph series and probably the Classe DR-3-VHC); and it looks like some Class A/AB amplifiers don't even operate in Class A where the load is anything lower than the nominal impedance rating.

Does the Threshold operate in Class A at impedance levels lower than 8 ohms? If it does operate in Class A at these levels, does it exhibit the de-rating phenomenon described above?

Thanks for your help.

Hey y'all,
I have some creative s700 speakers that need replacing. One of the surround speakers has a cut in the outer surround of the mid driver. So ive decided to open and have a look. These are 2 way speakers and have a crossover inside the box. The tweeter is rated at 4 ohms and the mid driver at 8 ohms. Im thinking of replacing both front surrounds to keep it equal sounding. Im thinking of changing the tweeters aswell.

Stock tweeter is 4 ohms and mid drive 8 ohms and then a crossover.

Im looking to replace with a 6 ohm tweeter and 4 ohm mid driver. Is this possible or i would have to change the crossover as well. Because the amp runs these at 8 ohms, so i dont wanna hookup anything less than 8 ohms and put more load on the amp.

I’m building a poweramp for my frfr guitar cabinet. I’m using the QuadCortex modeler as a preamp. Currently I’m using the Harley Benton GPA-400 as a Poweramp, but I don’t like the sound, it gets harsh as soon as you turn the volume up.
As far as I know Seymour Duncan is using Icepower modules for Powerstage amps. So I was thinking why dont I just build an Icepower 700AS1 module into my cab. One device less to drag around.
I was expecting this to be easy but the result was not what I expected. It sounded good when I had the QC volume at half, but when I turned it up the sound got all distorted and wasn’t as loud as I would expect.
The dealer explained to me that the output voltage of the QC was too high for the Icepower amp.
From the QC manual:
Analog Outputs 1-2
• Connectors: (2) XLR-M with Ground Lift
• Impedance: 560 Ω
• Max Output Level: +9.5dBu
Analog Outputs 3-4
• Connectors: (2) TRS
• Impedance: 560 Ω
• Max Output Level: +15.5dBu balanced, +9.5dBu unbalanced


“Quad Cortex 4.6V (calculated from +15.5dBu). For the 700AS1 the max is 3,3V.”
Basically I have two questions.

• How do I fix the Voltage/ Ohms mismatch issue?
• What would be a good 3 band eq solution to add?

Thanks!

I have this F1 Psu, 2 single rails of 24v. Been using it to power 2 X ACA.
I wish to try my 3255 class d amp and it wants for single rail 48v or so.
Can I put the two 24v rails in series? The two grounds for the rails aren't connected. Separate windings and rectifiers.
It has 35v caps. Is that still ok or would I be putting the sum of the rail voltages thru them? If so it's a no go!

…and not resistors?

That is, why don’t passive x-overs use RC and CR filters, instead of LC and CL?

(And yes I know that speaker impedance is normally used in a CR configuration for high-pass filters, but my question is on a more theoretical level, just out of curiousity.)

I'm working on a project based on a powerful SBC. I want to make a closed loop and custom make a dac and adc for it. The board itself has a lot of great I/O including 2.5Gbps ethernet, USB3, and thunderbolt 4, as well as arduino. Which would be the easiest vs most worthwhile to implement for data transmission and collection? Or would it behoove me to choose one more than another for a specific use case?

Hello there =)

I'd love to get some buying recommendations for new speakers and thought this might be a good place to get some advise.

Currently I own a Creative Sound BlasterX Katana (v1) for my PC setup which is a soundbar with a peak output of 150W and a 75W RMS. It has two 2.5″ (63.5mm) Upfiring Midbass Drivers, 1.3″ (34mm) High-excursion Tweeters and a 5.25″ (133mm) Subwoofer Driver. I like the sound of it, it fills the room quite nicely. However I'd like to switch to a pair of speakers to get some stereo sound.

Here are my requirements/wishes:

• They shall sit on my desk, so not tooo huge
• They MUST be available in white in order to fit into the setup
• Price range is about 300-500 € for both speakers
• I was thinking about studio speakers but am unsure weather these are the right kind for me
  • I like to listen to base heavy music (techno, etc)
  • I also watch quite a lot of youtube videos with just talking.
• Do I need a subwoofer? I guess if the speakers are large enough I should get away without using one, right? But it's also fine if I need one

Additional facts:

• The room has about 60 m³ of volume
• The speakers would be about 60 cm away from my ears
• I was thinking about tilting them up to an angle to point in the direction of my ears. Is this something to invest in?
• I like the boxy look (e.g., yamaha hs7w) and not something like the Bose Companion 50

Thank you in advance for your help!

i have one kit , full populated board like photo , Albarry M408 clone , ship everywhere in the world.
link ebay :https://www.ebay.it/itm/364559504711

Hello, I've been repairing amps for over 55 years now. I've seen many different brands, units, various state of dammages and self inflicted whatever. So you could say that at my age I've seen it all...
But no.
A few days ago I saw a post on these master volume pots for a Fender Twin. You know, the one with the Push-Pull switch.
A twin (combo) came to visit my bench and to my delight it's equipped with 2 orange JBL's 120. Second time in all these years that I encountered this model.
But nostalgia on the side, the volume pot had a problem. I checked the inners and found that the carbon track was broken. I happens that this potmeter is no longer available. So I have to rely on some other version but it seems to be to tall. No luck.
Until I read that article, somewhere...
It seems that CTS pots have the same pcb with various carbontracs (resistance). I had a Mesa Boogie volume pot in my collection and swapped the small pcb.
It fitted 100% and the twin has a fully working volume pot again.
Except the tap for the high pass cap is'nt there. No problem, I placed it over the in- and output of the pot.
So, to make it short (?), all you younger technicians: You are never to old to learn something new. Most of the time it's hidden some where.
Can I say that I'm a dinosaur?

Which one will sound better?:
an AK4493 or a ES9038 based DAC

Hi,
Can't find hardware to fasten PCB which is perpendicular to heatsink. Something similar like with LM3886 chips used on Modulus Amps.
The chips are on the market, believe some hardware to fasten PCB should also be available...Any ideas where to find?

Hello witches n warlocks

A seller locally is offering a pair of tympanis quite cheap. I've been curious for a while about using planer or electrostatic subwoofers. I don't need to get down to 20 hz or anything but 30ish to a 100ish.

As the timpani has two base panels for each side I'm curious what my my considerations be in arranging each in a riplole or slob config. From what I read about that design the main problem that comes to mind is the huge surface area which leads to a huge slot. The solution that comes to mind is maybe some dividers to shrink the slot into multiple chambers. The problem there of course is it will be hard to impossible to seal each chamber from the next. But maybe that won't be a make or break issue as long as the frequency ends up being usable up to about 100 Hertz.

I do have a couple of high wattage amplifiers and DSP available for subwoofers so if there is a massive peak can I just EQ it out?

On the plus side with no motor sticking out I can make the chambers quite small on either side.
I don't really know what I'm doing so this might be a bad idea based on something I haven't even considered which is why I'm posting here.
Thank you to all who contribute to the site it's a wonderful part of my life and has given me a new hobby that is wholesome and really cool

Placing my order for JB's Aikido line stage 9 pin version this weekend. I would appreciate inputs on the Noval stereo pcb vs the 9 pin dual mono boards? Are dual mono's adding complexity not worth the squeeze or not a big deal? Looks like the PS-21 is suggested for the stereo Noval board. What would I use as a PS from his site for the duals? Comments on his attenuator, power 3 position switch, input selection switch boards? Transformer recommendations for either of the above from folks who've built them? Thanks

https://glass-ware.stores.turbify.net/ainost.html

https://glass-ware.stores.turbify.net/aik9pindualm.html

I have small circuit or "sub-circuit" that will be repeated several to many times as part of a larger analog active circuit that is to be implemented on a PCB. I would like to make something versatile and flexible because the overall circuit might use four or fourteen or whatever number of the sub-circuits plus a few other auxiliary signal processing circuits. I am thinking of perhaps a physical arrangement consisting of a motherboard plus edge connected daugtherboards. Or making the sub-circuits on small PCBs that can be stacked up on top of each other above places on the motherboard PCB. Once the PCB is built it would not need to be reconfigured. I am only interested in making a flexible implementation overall.

Are there any other techniques that might work well for audio?

Are there some problems with or concerns about small PCBs that stand off of the main board, e.g. regarding noise or physical staibility?

After learning Jung's paper about CCS and some discussing in this forum, I pieced together this circuit. Choosing 2cs2705 is because of its high linearity, high hfe, and low cob. Choosing crd can increase the psrr of ccs, but it needs 10v to work well will increase the voltage drop. Using LED series connection to reduce noise. Another CRD keeps the operating current of the LED constant while improving the PSRR. Any suggestions?

I have a Proton AC-300 MkII CD player purchased in 1991 and the 7 segment green LED display is not illuminating.

Similarly the Time, Track, Pause & Repeat single LEDs are not lighting up when the appropriate button is pressed. Otherwise the CD and remote control sensor (which is also on the display board) are functioning perfectly.

The LEDs are all controlled by two CD4052B differential 4-Channel multiplexers and the 5 volt power rail seems to be OK to these ICs. Does anyone have a schematic or block diagram of a Proton or similar CD player with a 7 segment LED display which I can use to fault find.

I would have thought a 7 segment display should be pretty easy to trouble shoot once you understand the how they are controlled logically.

Thanks for your help

Hi Guys.

So, a follow member (Bumbledad) gifted me a new pair of Heil AMT drivers. I decided to build a pair of speakers with parts I have in the shop.

I have a pair of JBL 6x6 horns and a pair of Dayton Audio DT250P-8 Compression Driver.

I also have a pair of DynaLab V22-DR-0003 8" Paper Cone Woofer 4 Ohm that have an f3 of 25hz in a 3 cu ft box.

The CD is solid down to 600hz out to 10khz.

so I want to cross the woofer at 600hz to the CD then cross the CD at 5khz or so to the Heils. I have an active three-way crossover and a handful of amps.

Below is a link to the woofers and a picture of what I’m thinking for the cabs but with the horn above the woofer and the Heils on top like the picture.

DynaLab V22-DR-0003 8" Paper Cone Woofer 4 Ohm

Hi there. Ive been a member for ages but this is my first post.

Want to ask about people’s experience with ER Audio speakers. But first a bit of background…

Recently got my hands on a pair Quad ESL63 speakers. Only had a chance to run them properly last weekend, and OMG I was blown away. My other speakers are Monitor Audio PL300ii so nothing to sniff at. But the Quads besides bass kick and extension are every bit as good as and in many aspects better than my Monitor Audio speakers. I couldn’t stop listening to them I was so blown away by the music being made by these wolf in sheep’s clothing. I messed with positioning for about 10 minutes and everything just clicked. The speakers energized the room, I could play LOUD, the bass reproduction was fast, textured and detailed… I don’t need to go on about the other aspects of the sound quality of the Quads as they are well known… suffice to say I was mesmerized by the 3d imaging just hanging in the air in front of me… I suspect the speakers are a great match for my room and equipment. I have 2 amps but the one that brought them alive was the Synthesis NYC100 valve amp. It’s a beast of an amplifier, it’s like having 2 refined 100watt mono amps in one 60kg package. The grip, extension, dimension and speed of the music being played just shocked me. (I’d disagree with using low power amps with Quads, quality amp first but then quality power really makes them come alive - I know they can only handle so much power, but it’s not about having a sledge hammer to crack a nut, it’s about dynamics and speed) My room is 6m wide x 5m deep, with an opening in the back wall into the kitchen, and side wall to another room, and the speakers just energized the room to the right degree. Just synchronicity…

Anyway, getting to the point, I’m obviously falling deep for my Quads and wondering how far I can go with panel and electrostatic speakers. I’ve obviously been reading about electrostatic speakers intensely since the weekend and I’d like to try something larger without going over the top.

Quad 2905 and 2912 are on my radar, but Ive been reading about the ER Audio speakers. I’d love to hear from anyone who has a pair and has lived with them for some time, and get their impressions of the speakers and if they’re happy. Especially if they have the Acorn model.

Looking forward to hearing people’s thoughts.

(References a commercial product so the mod might need to redirect this post?)

Just saw these on my IG thread and had to share

Me likey very much. Also Cute amp to match.

Collab between http://www.wiener-lautsprecher-manufaktur.com/
And
http://riokobayashi.com/

This is a Group Buy thread for a ready to run (RTR) Best Thing since Sliced Bread (BTSB) Panel Mount universal buffer. More info on this very handy and superb sounding buffer is available here.

Briefly, it is a panel mounted PCB that accepts XLR/TRS balanced input or single ended (SE) input via RCA and provides buffering and selectable gain of 0/6/14/20dB and simultaneously provides balanced output and single ended output.

There is a an auto sense switch that activates a small high quality signal relay to disconnect the RCA inputs if anything is inserted into the balanced jack (TRS or XLR) and this is to prevent overloading the buffer with signals from two parallel sources. This automagic operation is balanced input priority. That is, the single ended RCA can only operate of there is no jack inserted into the XLR/TRS jacks.

The design is by Jhofland and sounds and measures superb. The physical design is compact and uses Neutrik XLR/TRS jacks plus high quality gold plated PCB mounted RCA jacks. This allows convenient mounting to an amplifier rear panel to keep line level signals from picking up noise inside an amp chassis. It uses a 12v DCDC converter to provide dual rail +/-15v supplies so powering it is easy.

It uses state of the art OPA1656 or OPA1642 opamps for the buffer and output SE driver, and OPA1637 for the balanced output driver. The performance is superb - low THD, inaudible self noise, and sounds clean and natural. Nothing added or taken away. Having selectable gains allows it to be compatible with almost any source/amp gain combination. Having the ability to fine tune the gain to 0/6/14/20 dB makes the BTSB suitable for driving almost any amplifier. Note that the balanced output operates at +/15v rails so with balanced output, can have an output as high as 60Vpp. This means that it could drive 0dB gain amps up to 50w (if 20dB gain is enough). When used with a 6dB gain preamp this gives 26dB overall gain. A preamp capable of 2vrms should be able to hit 50w into 8ohms in a 0dB gain amp stage like an F4, etc.






This board is actually used as the buffer in the well-reviewed LSA Warp-1 amplifier.


The design was made by Jhofland and if you are familiar with his other projects, you know that they just work well and sound great.

Here is the schematic:


Measured distortion and noise at 2.0Vrms output using Victors oscillator and Focusrite in loop back:


The BTSB Panel Mount buffer in RTR trim just requires you to provide a 12v (about 200mA) PSU connection, and connect the outputs (JST 2 and 3 pin jacks) to your amp. You now have a clean way to connect your amp to balanced or SE sources and you can drive balanced or SE amps. A nice feature is to use the balanced to drive your amp and route the SE as a pass through to drive an external subwoofer amp or even for bi amping.

I am offering the RTR BTSB Panel Mount buffer for the price of $165 ea as a GB. After this the price will be $215. Boards will be professionally assembled with robotic pick and place using genuine components from a BOM that I carefully specify.

If you are interested, please add your name and number of units to the interest list below.

Name / Number of Units / Country
——————————————————

Hi All.
I am trying my hardest to find a good enough reason to bias an opamp like the LT1115 into class-A (according to an RIAA preamp on the LT1115 datasheet).
The distortion figures of most modern opamps are already vanishingly low. What is the advantage then of biasing these into class-A? I have tried to build a small circuit which does this using a BF245 Jfet. On my scope, I see no difference between the circuit in (2mA draw) and not in.

Can someone please help me understand..better still, are there any before after scope measurements? ALSO... lastly, does it improve the audio output significantly enough to justify adding 2 components to boas the device?
regards Robert

Hello,

I have a Yamaha RX A830 in protection mode everytime I start It ! Managed to turn It on to self-diagnostic mode, showing DC PRT 2L.

According to the manual, Cause: DC output of the power amplifier is abnormal.
Supplementary information: The protection function worked due to a DC voltage appearing at the speaker terminal. A cause could be a defect in the amplifier.

I checked and I have -5V on one of the Front Right (FR) Channel, only in speakers output (others output are around a few mV, same for preamp outputs)

A friend of mine took It, cut, removed and tested the output transistors marked in green Q1052C and Q1052A. Working correctly, PNP and NPN. We tried to start the amplifier again without the transistors and still -5V at the speaker output, and circuit protection still triggers.



My guess is that the first stage of amplification might be faulty (labelled Q1038 and Q1045 if I get It right) ? Would you identify other usual suspects ?

Nothing seem burned/boiled/exploded/.... as far as I can see.

Thank you 🙂

Dear All,

I found a SEPP circuit from an old magazine of year 1966 as Fig-1 shown. It was using an output transformer which has two groups of primary windings. Can anybody explain what is the different if using a single winding transformer as Fig-2 and the advantages and disadvantages in comparison?

Thanks

Patrick

I've no idea of the T/S parameters of my dumpster sub's driver. It's in a 16 litre ported cabinet tuned to 52hz. I like the sound the box produces. At high listening levels the driver behaves as expected. However, if I block the ports the driver readily hits Xmax.

Is this a Q thing?

"I have a problem with a Class AB amplifier, Rod Eliot's P3A project. I assembled the boards, but when I inject an audio signal, I noticed that the sound is coming out low and distorting at low frequencies. Does anyone have a possible solution?"

Dear friends,

I'm looking fora data sheet of the Vifa M25WP-00.
Can someone help me with it?

Thanks anyway.

Well done! The 1 point victory margin side.

Makes me proud 👍

Bought an assembled preamp from another forum member. One of the non-phono inputs has some issues (left channel is out, right channel level is low). I have a friend that is an electronics tech and I am going to ask him to see if he can fix it. Does anyone have a schematic?

65 views and no responses. I found one here: https://www.hifiengine.com/manual_library/elekit/tu-8500.shtml

Shiv Naimpally

I am planning on building a headphone amp for someone with age related hearing loss using simple attenuation on the input with a fairly high gain opa 604 based amp to compensate for that, maybe x5 to x10 voltage gain. I think that once hearing loss starts affecting speech intelligibility (presence region) the highest frequencies are probably not recoverable so this is just a simple shelf filter with a six way switch to adjust the frequency range maybe starting at 1 khz up to 8 khz with a simple stereo pot to adjust the level of the higher frequencies. I’m not trying to get a complete fix just something that improves the situation for the television, films , music etc

Please let me know if there is a better way of doing this or if you have tried this and had any good results. Thanks

Hi, I just got a pair of Reference 3a M3 Generation II and would like to retrofit the tweeters. From what I've found, it look like its a Vifa D-26TG.
What is the best retrofit and do I have to modify the crossovers ?

many thanks

I am replacing a failed standby power transformer (seems an often enough issue on these Onkyos) and have come across this crud accumulated at the inductor and connector solder joints of the HDMI board. I am going to clean this up, but was wondering why it got there in the first place and whether this buildup is something that can cause issues with operation. Onkyos from that vintage had HDMI problems that were blamed on the main DSP chip, solved apparently by reheating it, but I did not have this issue, though I never did run video through it. I had random shutdowns for a period of time and then total failure to come on and found that the primary on the standby transformer was open and am replacing that now.

See if anyone have it. thanks

Hello to all,

I would like to do upgrade from 2SB649/2SD669 on my amp LJM L12-2. It's nice to do shopping on AliExpress, but ... I would prefer to get Toshiba TTA004B/TTC004B from mouser.com

I noticed 2SB649 has emitter to base voltage -5V, TTA004B has -6V, should I change some resistor or something? Does it matter? 😀

Thanks for help!
Milan

Datasheets' links:
2SB649
2SD669
TTA004B
TTC004B

I take speakers apart, that's my thing. I'm fascinated that with a piece of paper, a copper coil, and a magnet you can reproduce any sound know to man. Electronics is not my area of expertise. I like to recycle. I try not to contribute to landfills.

What is the value of a transformer?
I've looked on Ebay. Some seem to go for silly money, others - not so much. I'm talking about audio grade stuff. 100Va +

Hey Guys,

Im studying Sound and Music Production and for my Bachelors Project id love to build a Synergy horn. Im at the very start of the whole Process and rn im gathering literature and Programms which will help me to succeed in my adventure.
The first big problem i came across concerns the simulation of a synergy Horn. Maybe i just dont understand but in Simulation Softwares Like Hornresp or AJ-Horn it seems impossible to Simulate all Drivers sitting at the sides of the throat. Any suggestions?
Further id be really thankful for any Tips and/or Ideas on how to start the Project. What are the first steps to build on to?

Thanks in advance

Elias

Hey Everyone! Me and some friends, are in the early stages of designing and building a control surface to work with the major, DAWS and most likely going to use MCU (Mackie Control Universal ) Or Mackie Control. We most likely are leaning towards MCU with its combined abilities. We are all from different backgrounds which, means we have to learn a lot of information about this, more specifically what MIDI data is needed to control specific parameters within the DAW I've backwards mapped it so far that to control the volume you hit (for example) G#6 plays at 127 velocities, THe pitch wheel controls where the volume is (Between 0-127) then G#6 is released I was wondering if anyone has any thoughts on this and/or any information on where I can find more information like this that will help us develop the device further. Cheers

I have 2 Ahuja horn driver. Details given in the picture attached.. i want to connect them in parallel connection and then with a 120 watt 8ohm speaker. So the resultant impedance will be 4 ohm.
I want to add one RC filter with each horn driver. But i have no idea about the value of capacitor and register . Please help me about this. I am a new hobbyist of audio industry. And sorry for the language.

I’m fixing a McIntosh Mac 4100 that I have and on of the faults was that the power guard/clipping LED on one of the channels is very intermittent and the clipping of the waveform on the scope isn’t great either.




After a bit of diagnostic work I found the fault was due to a failing optocoupler.




Here it is in the 4100 circuit.



Does anyone know of a replacement I could pick up from somewhere like Digikey or Mouser? I wouldn’t trust any of the ones coming out of China that are littered all over eBay to meet the spec of the originals.

I’m not sure what to do if I can’t buy some replacement that will work in the circuit. If someone comes up with a replacement I’ll make sure to buy multiples for future encounters if needed.

Thank you,
Dan

any here able to decipher a Sylvania 539 date code?

I apologize if this has been thought of and/or discussed.

I am doing some ltspice simulations and it occured to me that crossover distortion in a typical totem pole push pull output stage would make harmonic distortion worse at the smallest output power that departs class a-ish operation.
eg for 1mA (hypothetical) idle current across the devices it would make sense that harmonics would deteriorate the MOST somewhere 1mA to 2.x mA output current.

This makes very low level listening an extremely different experience than the typical half power or 80% output situation measurements

For my particular simulation, THD @ max usable power (100+W) is < 0.0005% but at 100mW its more than 10 times worse.

Any thoughts?

I have coming a pair of Kef B200, and a pair of Vifa D19TD which was suggested as a T27 substitute on this forum. I like it and it's used in my Mission 761 speakers. Similar 19mm poly dome.

What would you suggest as a crossover for a 2-way in a sealed cabinet? Typical X-over frequency is 3.5K

B200 SP1014 + T27 were used in Cantor(1971), Chorale(1970), KEFKIT1(1974), Monitor Audio MA4, Linn Index Mk1, Tangent TM1, 2, 3

Chorale crossover was SP1015 or SP1016

SP1014 – constructors, small magnet, Chorale
SP1022 – Qts .41, large magnet
SP1039 – med. Q, large magnet 104, 104aB, Monitor Audio MA4, 103 Ref. Best
SP1054 – Qts .23
SP1063 – med. Q, small magnet

SP1047 (1974) Used in: KEFKIT 1(1974)
SP1054 1976 Used in: Calinda(1976)
SP1063 1976 Used in: Caprice(1977), Corelli(1976), C40(1979), C65(1979)

Attached Monitor Audio MA5, Tangent TM1 and TM2

I have 8 Altec model 15095A octal plug audio transformers for sale.
I would like $75 each for them individually or all 8 for $500. I will cover the cost for US shipping.

Amp clips unevenly with no load attached, with load it cannot drive it properly, sinewave gets distorted and the top half is being cut off.
Rail voltages are equal, aux voltages are fine. New driver IRS2011, new gate resistors, diodes, recapped and etc. Nothing is heating up, no abnormal current draw.

Schematic is attached, but it's a different revision than mine.

There are two resistors which are not present in the schematics but are in my board (check drawing). These have been changed in the past by someone else and i'm not sure the value of 100ohm is the correct one.

Amp uses fb31n20d but as these are obsolete i've tried so far with no avail with outputs as:
IRF1310N
IRF640N/IRF540N
IRFB4227
IRFB5615
SSP45N20A

I'm also using bipolar electrolytic capacitor instead of a film one for C83 as I don't have film one 10uf.
Logic input for low and high side gate driver outputs at the ir2011s are same regarding amplitude (HIN+LIN).
So is it something with the feedback circuit or these resistor should be 100Kohm instead of 100ohm ?

This upgrade gives you extremely low distortion from the tweeter, better pinpointing, better off axis and power response. And the good old Vifa C17 has a magic warm midrange. So if you want a high end speaker on budget who is a easy load for tube amplifiers etc. Good luck 🙂

PS!

1) you must plug the port with foam or a big sock, or even close it with a plate

2) the 0,68 uF paralell resistor on the tweeter can be removed if the 0,56 mH inductor have high dcr

3) yes, it is a series resistor on the woofers, if you dont beleive it sounds good, please find another project 🤭

4) if your sofa is high, make a 10-20 cm base

5) be careful when you cut in the tweeter opening, use a lot of gaffa tape to mask and protect

6) a little extra damping with f ex bitumen inside doesnt harm

7) have fun 😊

Hi Thanks for reading There are quite a few ljm quad amp boards available from ali, ebay etc, such as 405. 606, 707. Which do you think will offer the best sound quality, have you heard anything or have any experience

Thank you

Dear friends,
My Garrard 401 uses 110v 60hz and the original 50Hz pulley has been replaced by a 60 Hz pulley.
However, when I turn on the turntable, the speed is around 31.xx~32.xx at the beginning. I will have to wait about 5 minutes to let it heat up to 33.3rpm (I know that 401 has warm up time!); however, the correct 33.33 rpm only lasted about 10 minutes, the speed will increase slightly after 30 minutes~1hour, turned into 33.4X~33.7Xrpm(+0.3~0.5 rpm), and then I have to adjust it back to 33.33rpm. Is this normal? Is it very nomal due to the temperature of the motor that makes it gain more rpm from time to time?
Attached picture is a record of the speed change in 40 minutes:



as you can see in the picture, in 40 minutes, the speed changed from 33.1x to 33.6x, (+0.5 rpm in 40 minutes) is it very nomal due to the temperature of the motor that makes it gain more rpm from time to time? so that after 40 minutes, I have to adjust the speed back from 33.6x to 33.33. (I use WOW rpm app on my smart phone.)

The idler and eddy brake disc are all in very well working condition.
Let me know if you have any ideas?
Thanks in advance!

Hello everyone,

I built a class D amp with the IRS2092s. I've been fighting an issue with the amp cutting out at higher volumes with a speaker load. I can get about 400-450 watts out of it before it cuts out. When it does cut out the output is not yet clipping, and does not look distorted.

Previously, I never tried to use a resistive load to see if it would behave the same. Today I tried it and I'm able to drive the amp into clipping with a 2 ohm resistive load and drawing well over 600 watts at the input and the amp did not cut out.

I'm not sure what to make of this. Any ideas on what I should play with to prevent it from cutting out with a speaker load? Could it be the inductor is saturating? The first stage inductor is only rated 10amps... 😀

I was recently reading through some old threads regarding using three (identical) loudspeakers for stereo listening. The most heated debate was already years ago.

I would be really glad to hear from everyone, who is using a three loudspeaker setup for stereo.

My own experiment with the Single Speaker Stereo (three fullrangers matrixed in a single box) were quite encouraging and I would like to experiment a bit more - especially with extended bass and more SPL - I will share my experiments as they will come.

I am especially interested in configurations where the speakers are relatively close together in a straight line close to the front wall - as that is my physical limitation for speaker placement.

I'm wonder about buying a pair of either MAOP 7.2 or MAOP 11.2 or 11MS.
I've had the Pluvia 7.2 HD which I didn't particularily like (needed quite a bit of BSC and sounded off).
I'm running pair of 7MS today that I'm very happy with but they need some correction in the 2-4 KHz area which they are a little bit hot, and I'd like a little more SPL capability in the bass (hence looking at the 11.2 and 11MS).

Does anyone have experiences with these drivers and can tell me a little bit about how they compare?

Hi, I found some diagrams of this amplifier that I bought used. It's very well placed 🙂
I opened it.
No burns on the PCB, everything seems normal (and original).
I would like to change all the electrolytic capacitors for 105° (many hours of life). I think it's good for him.
Do you have any advice other than large smoothing capacitors?
Are some caps for low ESR or do I all use normal caps? Panasonic? Any recommendations for which series? Nichicon?

Do I need to replace some other component (resistors, diodes) with something more "higher wattage"?
I thought I had read that MF had made a mistake in calculating the wattage of the components... but I don't remember whether on the A100 or A1 and which components.

Any other suggestions of things to do during the recap?
Do I need to check the values of the resistors that determine the polarization and the quiescent current?
Thanks, I would like to make this review as soon as possible and..........happily listen to it.
Thanks for any advice.

might be best explain with an example:

I have a relay protection circuit that uses a 7805 regulator to bring down the incoming DC to operating voltage. I am thinking of using a small AC-DC power supply (example: https://www.meanwell.com/productPdf.aspx?i=677#1).

Is there a requirement to tie the power supply grounds together in this situation? thanks

I recently built a single two way speaker with a Dayton 8" woofer, and the "skinny" GRS planar driver PT6818. This was just a relatively low cost way to play with the GRS planar, and I'm really enjoying it. Now I want to go all in on a pair of speakers for my living room.

I'll admit to watching Paul from PS Audios videos on YouTube, and while I take things with a healthy grain of salt, the FR30 design fascinates me. I threw four of the new Dayton 6.5 signature woofers in a series/parallel config, and the large GRS planar mid-range and tweeter, and it models real nice with a relatively simple crossover network.

Has anyone used these drivers? They'd be the GRS PT5010 and PT2522

Hello,

Bought these for a speaker project, but no longer need. Lots of low distortion, clean output. Made for a closed box of decent size, not ported. Could also work in IB/OB/dipole, though I didn't try that.

$147 each, or $273 for the pair. Prices are firm and fair. Local pickup in Los Angeles only!

Details:
https://www.parts-express.com/Dayto...-Series-HF-Subwoofer-4-Ohm-295-468?quantity=1

Features:
Extensively vented motor eliminates compression and allows quiet excursion
Lightweight black anodized aluminum cone for rigidity and lower moving mass
Triple shorting ring motor for ultra-low distortion
2-layer coil for reduced back EMF
Suitable for sealed or vented enclosures
Highest quality materials throughout for long-lasting performance

Specs:

Nominal Diameter 15"
Power Handling (RMS) 500 Watts
Power Handling (MAX) 1000 Watts
Impedance 4Ω
Frequency Response 18 to 800Hz
Sensitivity 91.2dB 2.83V/1m
Voice Coil Diameter 2.5"

Thiele-Small Parameters:

Resonant Frequency (Fs) 19.5Hz
DC Resistance (Re) 3Ω
Voice Coil Inductance (Le) 0.92mH
Mechanical Q (Qms) 3.02
Electromagnetic Q (Qes) 0.5
Total Q (Qts) 0.43
Compliance Equivalent Volume (Vas) 7.49ft³
Mechanical Compliance of Suspension (Cms) 0.22mm/N
BL Product (BL) 15T·m
Diaphragm Mass Inc. Airload (Mms) 306g
Maximum Linear Excursion (Xmax) 14mm
Surface Area of Cone (Sd) 829.6cm²

So years ago, Number One son and I built this Plasma Speaker from the Kickstarter...

https://www.kickstarter.com/projects/excelphysics/the-arc-plasma-speaker

A supercool little project...I actually looked at building a speaker set with these doing 2k and up...until I realized the shock danger and Ozone emitted... too bad...

Anyway I work with many fellow Engineers and Accountants... I am always amazed at how simple and Un-Technical these Accountants (I WORK WITH) are...no offense to any of us that are....

I setup a little Demo of this plasma speaker at work one day...

Engineer #1 - that is soo cool!!
Engineer #2 - Where can I get one!!
Accountant #1 - My Dell Desktop speaker sounds better.

Sigh....

As the titles states, I'm looking to buy some 0.1 2W Axial resistors with lead spacing of 20mm . I need 12 of them. If you have some extras in your bin willing to sell, please PM me.

Rick

I'm new to the forum, Greeting to everyone!

I use a Raspberry PI 3 model B+ with MoOde Audio to a USB DAC to an Integrated Amp (with volume Knob).

What are the correct "Audio Output " settings if I intend to control the volume only from the amplifier knob?
Fixed (0db output) or Null (External Control)? Is there any difference?

Hi friends

As the title says, my TD 125 (MK II) has quite a on-off thump. It of course gets amplified just as much as the tiny signals of a low-output MC and thus is a bit annoying (but not more).
What could be done, could anything be done?

Many thanks!
david

Hello everyone,
I have a few Elma switches for sale.
1 new 3x6
2 new 2x6
1 used 2x2
Plus 1 damaged switch. It was originally a 4x2 position, but two of the pins were broken, so only the 2x2 position can be used.
The price is 40 Euros plus shipping and 5.5% PayPal fee.
I'm shipping from the EU.
Regards, Dezso

Hi,

I am a proud owner of a reasonably well functioning Pioneer SX 680 but I am craving a long project, so I plan to make this receiver work well for the next 20 years so I plan to :

• Recap it completely (and change know problematic transistors)
• Remake the exterior fake wood trim in real wood
• Replace the bare speaker terminals for banana terminals
• Replace the light bulbs with LEDs
• Replace the STK modules with the discrete design that rcs16 made and posted in audiokarma (maybe, I'm not sure now if I will be embarking on this one, the STKs are working fine for now)

As I live in South America and electronic and quality electronic components are expensive and sometimes unobtainable I plan to buy a restoration kit with all the components so I can save time and headaches, so, my options are

• HiFi Audio : Their kit seems ok, but there are not good feedback from the seller and their kits (and their support)
• marblehead199 : Their kit seems ok too, there does not seem to be any opinion of their kits in the web
• peace.love.and.music : Their kit seems fine too, there is one good commentary about this selller in audiokarma and it seems that is an active member of the forum with good reputation
• Cool and dry : Their kit is cheaper, but it seems that has less components than the other ones and it's half the price, bad reviews in reverb

I was looking into some threads in audiokarma for a part list but they are usually incomplete and/or other members comments that is wrong or something like this, but if anyone has a part list (or a mouser / digikey cart ) and can assure me it's correct I can go the route of buying the parts myself

And before that I know they're gonna be people that will say that this kind of project does not make sense in a lower tier of vintage receiver and that I should get a better one, but right now, here people are asking 3500 USD for an 1250 and god know how much for an SX 1980

If anyone had any experience with any of these vendors and their kit, the feedback would be appreciated

Thanks
Alex

I have a somewhat old multichannel receiver that I'd like to use for prototyping - it has DVD-A/SACD inputs that bypass the filtering etc which is handy for me, and claims 100W/channel. Its Arcam and very heavy so that might even be believable.
It says '8 Ohm speakers' on the back.
I have quite a few 4Ohm nominal drivers (Re is probably 3.5Ohm) that I'd like to play with, active DSP upstream of the receiver.
What's the worst that can happen?

I am looking for tuner string diagram for a maranta receiver model 28

I am wondering how to determine the wattage needed for the 20ohm resistor in this crossover. I'm running 100 watt sensitivity speakers and the amp puts out 10 watts or less.
Also, how important is the inductivity of the resistor. I have some wirewound resistors but they are not non-inductive.
Thanks in advance.

The included 2 x 48V 250mA switching power supply were not found. Selling AS-IS. You can purchase any high quality switching power supply or use 4 x 12V battery to power your gear although I never use battery for these two sets before. Output can be set between 15V and 20V by selecting the onboard jumper position.

I used these 2 units to upgrade the analog power supply for my Mark Levinson 38 preamp and the result is stunning until the day I switched to tubes. These sets have been sitting in my drawer for years. I have a DACT CT-101 preamp for sale too. Please take a look if you are interested.

These 2 sets have never been modified, you can observe that the motherboards were untouched.

Price is fixed including USPS shipping to the lower 48 states.

Purchased this preamp from DACT 6-7 years ago for a project that never started. Just found it at the bottom of my drawer and would like to sell it to those who wants to try.

The board has never been used, never put electric on but soldered on the CT2 only. Therefore, it is in perfect new condition.

$300 including CT101, CT2 10K and USPS postage within the lower 48 States.

What you see is what you get. I can't find the power supply wires.

PS - I have two CT-102 regulated power supply but I am still finding the switching power supply units that comes with them. They will be put on for sale as soon as I found the switching power supply units.

can someone provide me ts parameters of pioneer

TS-W1202D4​

driver.
thank you.

Hello, I'm looking for a tweeter for replacing one in an existing loudspeaker, with the following features:

• horn loaded or compression tweeter
• overall dimension: 110 mm round diameter
• material: silk or similar, not metal;
• sensitivity: over 95-100 dB/W/m;

recognized high fidelity qualities.

Any suggestion? Thank you very much.

Hello everyone. I repaired loudspeakers in Budapest for 25 years, but towards the end they brought work from neighboring countries as well. I stopped repairing, and there were several reasons for this. There was no room for improvement and creation is closer to me, so I started making speakers. In addition, I would like to move to a farm where production is more feasible, but repair is less. But so that the collected knowledge would not be lost, I wrote down everything I could in a 516-page book. It contains all the information necessary for a beginner with basic technical knowledge to repair any speaker. I described in detail what tools, chemicals, solvents, adhesives and how we used them for the work. In the first 9 chapters, I show you how to make different voice coils, change surrounds, repair diaphragms or spiders. Chapter 10 is all about repairing tweeters. Few people undertake these, so I deal with the topic in more detail. You can find out how to e.g. to wind a dome coil, to make a ring membrane, or to correct their errors. Since there are even fewer people who repair ribbon tweeters, I will show you how to repair five different ribbon tweeters... or make diaphragms. Chapter 11 is about professional speaker assembly, and the last chapter is about making speaker components. I present how, from what, and with what tools paper membranes are made... and I even describe the recipe for my own membranes. In addition, I show how I make plastic and metal membranes, spiders, surrounds, dust covers, tweeter membranes, or flat wire. I think this book fills a gap in this profession, but judging this is not my task. The book can be found on ebay, but you can also order it from me via Paypal. The price is $75 + shipping. I am happy to answer any questions.

I'm planning on a next, hopefully more definitive, project, since someone can get me drivers otherwise unobtainable or really more expensive here.

I like my actual WAF with 6.5 selaed speakers, so i thought i could point my setup in the right direction getting a better High end.

From my research (mostly here) i think 3fe25 is pretty much as good as it gets on a budget, considered CHN-50 but i would rather go with an 8 ohm driver. (TG9 would be interesting but couldn't source them).

Then i sort of liked the 10F/8424G00 because it seemed less inclined towards highs and beamed more harmoniously. But it's over my budget. (They are selling them quite cheap at speakerland if shop is reliable and someone is interested but they don't send to Spain). Then i found the 10F/8414G10 which seems pretty like the former yet at the same time, pretty much the same as 3fe25. I compared this two links:

https://www.dibirama.altervista.org...f-4424g00-extended-range-4-4-ohm-30-wmax.html

http://www.dibirama.altervista.org/...tal-3fe22-extended-range-3-8-ohm-40-wmax.html

And yes, the SSpeak has a little less distortion, a hair more of bass, and seems a little more consistent in the high-end. But apart from that, the other is more efficient and has like doubled Qms.

I don't want to start hoarding FR speakers so ideally this will be the last for some time (forever tweakable tho), and as close to a studio monitor a WAF can get.

Its that situation were u see that first brand pretty thing thru the window and you loose a little perspective. But from a rational point of view, i seriously doubt i could differentiate those two speakers and one cost 3.5 times the other, specially if i get to tweak them a little.

If u heard both of them, and specially, if you played with both of them, given my situation, what would you do?

Of course i accept new drivers recommendations but i rather just decide on something.

Thanks for getting this far 😉

Show your aperiodic speakers.

I suppose there are enough active DIY hobbyists who have actually built aperiodic speakers.

Please explain your design philosophy. Why did you choose that particular construction, shape, materials, etc. How do they sound? Are you satisfied with their performance?

Hello,
Please feel free to express your opinions and advice here.
My audio system is mostly intended for monitoring soundtrack production for self-made films at home. I'm aware that active monitors are the best quick solution. I had before some Adam A3X monitors + subwoofer and they were fantastic. But then I sold them and built my own class-A (JLH 4ohm) amplifier, to learn and start from scratch. The amp is great and loud enough for monitoring, but I haven't found a good set of passive monitor speakers for it.
Currently I'm using a pair of second hand Braun L470 boxes that I really like for their flat form factor, since my studio room is small. Combined with an active subwoofer they do well, charm and soft, but I miss the sharp responsiveness and detail of my old Adams. Sweep tests show that these boxes are not very responsive over 10kHz, so I think changing the tweeters could a be solution. I never built speakers, I've only read about it, but I can imagine also that after 30 years the drivers have lost tightness and their soft signature is basically HD. I haven't opened the boxes yet, but I'm considering to change both tweeter and woofer for some modern ones, striving for a flat frequency response between ~80-15kHz (a subwoofer stands below).
I don't know if, since the boxes form factor, damping materials, protective net and construction in general, are exclusively designed for the original drivers, any change of drivers will end up in a complete mess, unless accurate measures and further modifications are made.

Also, if this project of modifying the Braun boxes makes sense at all, I'm also doubting about the type of tweeters to use in exchange, Dome or AMT. I loved the detail and HFR of my old AMT Adams, they really replaced my headphones for fine mixing. But I didn't like the limited vertical dispersion and never really tried good quality dome tweeters to compare with, some SB Acoustics domes that seem popular now.

Any words on this will be highly considered! Since I feel my inexperience on this.
Regards,
Domingo

Attached are schematics from the Audio Research LS7 and LS22. I'm trying to determine to what extent the LS22 is simply a balanced version of the LS7. The circuit looks similar to me, but I don't understand it well enough to grok the implications of the changed values/sections.

Downsizing a bit. Bought in 4/26/2021 in the middle of the pandemic. 1.2 Meters (4 feet) long. Similar to their current "Black Magic Power Cord" (https://madscientist-audioshop.com/presta161/index.php?id_product=103&controller=product). Paid $599 plus tax/ship. $300 obo.

Been tracing out this new es9039q2m DAC to give it cleaner supply to the relevant parts. Does anybody know how the voltage ist regulated in the following configuration?

I can't find where the pins 3 and 5 of the OPA1612 are going to. They certainly control the output voltage. Haven't seen this regulation scheme before.

I am selling my SLOBS for $500. I built them at Speaker Camp 2023:

https://www.diyaudio.com/community/...ly-2023-pass-slob-northern-california.399813/

They are as new, though they have a few tiny marks from transport. The speakers must be picked up in near Berkley.

Please let me know if you have any questions.

Hey guys,

I'm interested in converting some cassette tapes to a digital audio format. I have a Technics Stereo Double Cassette deck and a ATI TV Wonder card which has RCA audio inputs, from which I'd connect the tape deck. I wanted to know if, given this setup, anyone knows if I would be able to convert these tapes and what kind of software I might need (and hopefully might be able to get for free). Thanks in advance.

Eric

I no longer need a current source amp so thought I would alter my diy F2J to get some damping factor, make it a sort of ZenJ. I don't want a lot of hacks, just short cuts not track cuts. The attached altered circuit diagram shows what I am intending. The revised input resistor values should get me into the ballpark of symmetrical clipping, and I am OK with the resultant gain and input impedance. Should I do anything else?

Many thanks in advance.