Hi sorry for the weird question
I would like to start to explain my goal In very few occasions mostly at audio show i have had the sensation that the sound were completely detached from the speakers
The speakers seemed like disconnected from the amplification units
Usually i can locate quite easily the sound inside the speaker
Often i read about a speaker sounding "boxy"
Question
Can we agree that a "boxy" sound can be related almost completely to the enclosure design and construction and not to drivers and xover ?
The boxy sound is one of the worst sensations possible Maybe even worse than distortion
What i find strange is that imho the cabinet design and construction issues are often overlooked
But the impact of a badly built cabinet could be immense
imho of course

I am Zoe!
Thank you for accepting me as a new member.
I am an audiophile and recently I just came into the world of pure silver conductors,
which gave me more comprehensive perspective about audio components in general.
So, I am interested on a new turntable.
As every discussion in the forum and every information is like a gold mine for me,
it would be great if you can share with me any suggestion or opinion about turntables.
Greetings🙂

As the subject says, I’m looking for a QuantAsylum QA451 Load.

Please send me a PM if you have one in good working order that you no longer need.

After playing the AP5.9bit audio for more than 20 minutes, a large current appeared, and the power MOS tubes (Q21, Q22, Q27, Q28) were severely heated and burned out. Measure the waveforms of pins 9 and 10 of TL494 with an oscilloscope. The frequency is normal at 46KHz, but the duty cycle is abnormal and very small. It is abnormal for the fourth pin to have a voltage of 1.7V. Finally, it was discovered that the damage was caused by the nearby capacitor C36. C36 is a capacitor on the 14 pin reference voltage output, which is constantly charging and discharging, causing a constant voltage on pin 4 and changing the duty cycle. I hope this can help people who have encountered the same problem

Hello all.

I'm thinking of using this device 2SK1828 as a source follower inside my bass guitar (currently passive pickups) , along with a 9V battery, to drive to the input tube of my bass amp (a 150H choke loaded 01A tube) , without any HF roll off when the bass volume pots are right down.

Is 1Kohm source resistor ok (10ma?) ?

And, can I bias the gate with a small battery? or a resistor divider network?

I am Argentine and I work as a live sound operator. I also build speakers and passive crossovers.

My music preference is about Disco, Dance, Electronic, etc. I own ADS L1590 speakers. They are floor-standing with dual 10” woofers configuration in sealed enclosures. I listen to them and I have ideas towards them. Firstly, they have excellent midrange and high. Secondly, they have very natural tone. Finally, unfortunately, they lack bass when compared to bass-reflex speakers or even modern sealed enclosure speakers. Regarding my listening preference stated earlier, I found their competitor from the same era; JBL L222 Disco, are passive radiator system and I believe their name clearly states what genre of music they were made for.

I just wonder if I could modify my L1590 speakers. Is it interesting and acceptable if I’m going to convert them to PR system? But, sure, I’m not going to destroy the original cabinets but build a new pair with same details and two new 10” holes at both sides and bottom of the cabinets to install the passive radiators there.

Next question is about the PR used. Assume I could find some L1590’s woofers, can I simply remove the magnets and voice coils from the units and use them as the passive radiator drive units? Because the remaining parts; cone, surround, suspension, and frame, should be identical to those woofers being used in the speakers. Is it that easy? Or does it require to redesign the cabinet dimension for PR system?

Hey people,

i want to give my speakers (2.5-way fully active floorstanders with 3x midwoofer/ 1x tweeter per box + 12" sub) a pretty massive upgrade.
I need 6, for a start 4 will do it (2 mw per box go from 90 - 500hz, 1 goes from 90 up to 1900hz) midwoofers. The speakers on my list for a closer look are the SICA 5.5H 1.5CP, the ScanSpeak 15W-8434G00 and the Dayton Audio RS150-8. As each chassis got it's own amp, and the amps shall be replaced, too (i'm in contact with the guy who designed the TDA7293 composite amp with JFE2140 input for i need 8 pcb's (plus parts from my local reseller).
Also would i like to change to active rectifiers and i'm drawing cabinets 😉.
I'm someone, who does diy not just for fun, but also to get as much music as i can for as less € as it is possible. Without used parts, i couldn't upgrade from the 30€ Gradients to a speaker one level in price higher.
So, if someone has at least 2 pair of 6"/150mm chassis wich could be an upgrade (I want more cone movement, for the gradients just go about 2mm up and down. I want to move more air), I'm happy for every offer.
the pic shows one of my speakers with the chassis which should be exchanged for something better.

best regards

Jochen

Hi guys.
A friend gave me today a SansAmp Bass Driver DI that makes erratic noise when using the XLR or TRS outputs into any console or amp. Someone had fixed it before but after a few days of use the issue came back. So he asked me if I could fix it.
I have no idea what the other tech did to this stompbox.
The symptoms are:
Erratic noise when used between an instrument and an amp. The noise is no hum nor a hiss.
When plugged to a console using phantom power on a balanced XLR cable, signal passes through the unit but the pedal does not activate (LED off). When turning off phantom power the signal dies.
Friend told me that sometimes it works but most of the time it doesn't.
I was thinking of a cold solder joint. The problem is that this unit has been opened before and in order to do that, all connectors (3 TRS and 1 XLR) have to be desoldered before the PCB can be taken out.
I did not jet open it, the solder points to the traces can easily be compromised the more I desolder all these joints. Also, I usually don't do SMP stuff...
Any ideas what the problem might be, before I take it on?

It might be time to put the controversy to "rest'.

The only real way is to actually make some amplifiers.

The best way to start (I might be wrong) , is to assume
that the simulator lies (slightly).
RNmarsh commented that many of his simulated (CFA) amps performed
much better when actually built and I have had VFA's that did not perform
as simulated.

To give everybody some "holiday meat" to chew on ,
the top contenders - that could change .... are posted below.

DIYA allows edit of first post ... ALL current work is posted here ! 😎

OPS - Amp is split into a output stage/ capacitance multiplier (simple regulator) PCB - 2/3/5 pair versions
are posted - Rated at 70/150/250 watts into 8R. With premium output devices this could be nearly doubled.
Triple output stage topology is used , as well as a 2 device compound thermal compensation circuit.
Similar to the Harmon /kardon 680 -990 series integrated amplifiers.

IPS - Separate small PCB's can plug in to the OPS. All IPS's will run off any supply the
OPS provides. CFA and VFA IPS's can be interchanged ... as the operating voltages
and currents are standardized.

Below is the "lineup" .....

1-3. SLEWMASTER OPS's (V1.2 -3 of them) the "baby" , "master" and monster".
......3 power levels of EF3 goodness. POST(s) #500 , 502 , 504

4. NAD-S-v1.2 IPS (CFA) - Based on the excellent "NX" with servo DC and the
Hawksford Cascode. Member NAF says "it sings" gracefully. 😀 Post #518

5. Wolverine-V1.2 IPS (VFA) - "blameless" based with PPM ultra low distortion.
Next logical refinement after the "Badger". POST #599

6. CFA-X and "XH" (CFA , of course) - Similar to the "VSSA/peeceebee" , a very simple amp usable
with the "slew" OPS's. POST #701 -perfected (684 is an error - do NOT use ! )
Edit ... post #2739 is the official schema for the "new" version for CFA-X "H" (hawksford powered).

7. Spookyamp (VFA) Based on the 2500$ Harmon kardon 990 receiver ... uses the classic
Georgia Tech "Leach" topology. Post #803 V1.1 ...

8. Symasui (VFA) - the DIYA "symasym" on steroids post #1628 , almost forgot this one .... Post #1628

9. Kypton-C (CFA) - better CFA-X with servo and super-pair. Post # 4729.

10. Kypton -V (VFA) "classic sansui" 3 stage IPS. Post # 5384.

11. EYESEE (CFA) - IC based amp - alexander amp .....post #4944

12. Kypton ND - (CFA) - best CFA to date ... post # 6782 test - post 6863

More to come ...
ENJOY!
OS








OS

Hello. I am experiencing a problem all would like to know your opinions about it. My system is using the stock radio but with an Audison DSP amplifier (AF M5.11 bit). The sound is wonderful. I've had the system for about 4 months but yesterday I started noticing that the sound coming from the front right speakers (drivers side) that are components (tweeter high, woofer on the door) goes on and off not in a straight direct way but in a subtle one. It comes with an interference sound (crackling?) and then when I set the balance to the right I hear the sound going down and then NO sound comes from the speaker only to go on full sound again). So, it's a subtle problem, it's not that the speakers would not sound, is that from time to time the sound goes off. It's very disturbing and now I'm talking to the dealer that installed it to check it. BUT I would like to know, despite what the dealer is going to tell me, what do you think the problem would be? A loose connection between the speakers and the amp or a problem with the amp? Obviously I would like the problem to be a loose connection and not one in which the dealer would need to replace the amp! Thank you very much!!

Refurbishing old amplifiers, I sometimes come across power supply bypass capacitors, 10 to 100 nF ceramics I presume for HF bypass, and almost always small electrolytics like 10 or 100 microfarad, LOCAL on (all) circuit cards.
Example: Luxman L309, SQ507 and alike main amplifiers have a 1 microfarad power bypass electrolytic and a 40 nanofarad ceramic one to each power rail on each power amp module.

However, such seem to be lacking on early amplifiers (now doing a Sansui AU555 from around 1970, but I have seen it on others, too).

What would be a good consensus about this, just leave it, or maybe just "add something thinking it does not hurt" ? Comments welcome.

I am placing this here since it seems like as good as place as any, especially since Mr. Pass designed it.

I was wondering if anyone has done a full cap replacement on this unit recently and if so would you have a copy of what the cap part numbers that were used are.

I have not had a chance to break open the unit since I picked it up. Not only that, but I purchased it from a gentleman who babied all of his gear but do to the age of the unit I would have to believe the caps could stand to be changed out.

I was also wondering if folks who would replace the caps if you would also replace some of the transistors, like the 2SC3298B (this would be discontinued, so I would need to find a suitable replacement).

Thanks in advance.

Hey Community,
I am researching some drivers to use in a 2.1 system. Has anyone used the GR Research M165 drivers? I can't find a lot of data on them. I was thinking on using GR Research X-SLS Encore Kit as the basis for my next project.

Any thoughts?

G

So why do I want to remove no-clean solder flux from a PCB? Well, I have a non-audio PCB that will have up to 900V across an SMT-style capacitor, and I'm just not comfortable with the idea of having that slimy stuff in that area. The other side of the capacitor feeds a current-to-voltage converter with a gain of 1e6 so it won't take much to screw things up!

The reason I'm asking in this forum is that the subject may be (is?) relevant to those among us who are vacuum tube aficionados; and, in fact, my application DOES use a vacuum tube (but it has nothing to do with audio -- it's a photomultiplier tube).

The best approach most-likely is to just use a water-soluble flux but then there's the fact that I assembled my board with the no-clean stuff before I thought of this potential problem 🙄. Water sure doesn't work...

Hi there

I saw an isolation power transformer. Triad n-73a. Can i use it as power transformer for my 5687 tube preamp (140vdc)

Thanks in advance

Erwin

The Pearl 3 needs +/-15V power. Hmmm, perhaps there is a wall wart solution which would save space and money. An old HP Printer of mine bit the dust and it has a +32V/5A supply. Maybe a filter and rail splitter. Here's the problem:

I traded speakers for a pair of 300 B monoblocks DIY build using 300B, 7119, and 5R4 rectifier
Comparing to my 45, c-500 monos, and several others these amps just don't cut it ---- the 300B's have no id of any kind telling me they are
on the low end of quality the amps have a lot of iron.... OPT's are huge --- looking at how to 1) improve these to amps or 2) build new amps using the OPT's and other parts of quality ?? what other amps might be made using these monster transformers? Or is this a mute question as more detail about the transformers is important to what can be built? As I understand, the transformer dictates the output tube it can run??

Writing to introduce myself

Hey friends -

I'm an electrical engineering professor in MN who develops loudspeaker simulation tools and guitar pedals, as well as doing research in acoustics, hearing science, and machine learning. Looking forward to chatting!

Greetings Friends, hope the holidays are treating you well. I've had a bit of a lull recently and had some time to think on my 6B4G project amp. Amp started life as a Lacewood 2.0 but I replaced the OPTs, added two DC heater supplies and installed 6B4G power tubes, now I got a SET.

The amp chassis only has 3 octal sockets, so my options for driver tube are rather limited; I've been using a 6SL7 with 100K on the Plate and 2K2 on the Cathode with 303v supply. Here's the schematic with voltages.



Being a tinker, I can't help wonder if this is the absolute best way, and some reading through old forums has given me the idea to try a 6SN7 as driver with 27K on the Plate and 1k5 on the Cathode. A look at the charts in the RCA manual tells me to swap out the following grid leak resistor with 220k, or perhaps smaller? Would my bypass cap need to change as well? Coupling caps?

Here's my proposed changes.



Will it work? Is it worth it? Should I change anything? Any Miller Cap issues to worry about?

Here's the power supply, if you're curious. This won't change. Thanks Matt for posting all the great designs. Hope you don't mind what I do to em.




thanks for taking a look!

w

When connecting from cell phone to cars USB port, do USB-C Cables with 100% silver cables sound better than cables that are not 100% silver?

Is there any correlation between a coil's effect on voltage & its effect on frequency?
e.g. If a winding reduces 240v to 12v what will be its effect on an audio signal.

Looking for ideas on the best subwoofer designs that can be stacked together in a cluster with the frontal area of 8x8 ft max or smaller. Depth doesn't matter a whole lot. Thinking a total of 8 or 16 cabinets, prefer tapered horn, open to all other styles. Powered by 4x amplifiers that are optimized for 4 ohms at 3500w x2 or 5600w x1. Need a solid output down to approximately 20 Hz and max SPL for electronic music. Easily maintainable in USA drivers. Can either assemble a flat pack, or build from scratch, or buy complete.

Now that the dust has settled on the DIY Sony VFET project, parts 1 and 2
we come to the design which accommodates the 2SJ18 and 2SK60 parts
which you may recall are the 1 die versions of the 2SJ28 and 2SK82 (which
have two of the same devices in parallel in the TO-3 package).

This design is for those transistors, and also for some other variations we might
want to play with, and like the parts 1 and 2 come in the flavor of the N or P
channel parts.

I have tested prototypes and purchased the pc boards and mounting brackets
for 300 channels, (150 of each polarity) and kits will be offered in the store soon.
This kit assumes that you have some of these Sony parts, whether hoarded for
years or freshly scraped out of an old receiver.

Also there are plans for versions using other fets in plastic TO-247 packages
for the store's UMS mounting pattern.

More information and documentation to follow shortly.

Hello Everyone,

I may introduce my latest speaker project to you:



Name: Edelstoff (german for "precious stuff" and also a beer brand from munich)



Type: 2-way constant directivity vented compact speaker
Impedance: 4 Ohm (> 2.7 Ohm @ 300 Hz)
Sensitivity: ~86dB @ 2,83V @ 1m
Response: 60Hz ... 30kHz +/- 1 dB, -6dB @ 47 Hz

Tuning: 10l gross / 8,5l net @ 45Hz
Crossover: Quasi-Linkwitz/Riley ~4th order @ 2.2 kHz acoustically

Cabinet: Birch plywood 18 mm, MDF 19 mm black colored, wax oil
Damping: 3.5 mm bitumen pads + 8 mm wool felt, Isobond WLG 040
Dimensions (w x h x d): 18cm x 33 cm x 27 cm

Tweeter: Seas 27TBCD/GB-DXT
Woofer: SB Acoustics SB15NBAC30-4 with additional neodymium magnet N42 d70/30x10 mm
Tube: Intertechnik Highpower BR/HP 50/180, drilled in the center for standing wave control (research state)






Drivers within the enclosure were measured in the garden on a tripod with turntable at a distance of 1m, mic 1-2 cm below the acoustical axis from the tweeter.
1)+/- 60° horizontally and +/- 40° vertically on a very slim speaker stand (see above in the first picture),
2) again +/- 60° horizontally placed onto the other speaker without gap (extension of the baffle downwards "to infinity", use case is e.g. placement on subwoofer or at front on lowboard/sideboard).

Single drivers in enclosure on slim stand:




Frequency response with crossover simulation in VirtuixCAD:



Comparison of placement on slim stand (solid) and onto the other speaker (dashed):



Frequency response hor +/- 60° on slim stand:



Frequency response hor +/- 60° on the other speaker:



Power response and directivity index hor +/- 60° (solid) and hor +/- 60° plus ver +/- 40° (dashed):



Phase and group delay:



Electrical filter response:



Speaker Impedance:



Crossover Network:



The 0° responses were merged with nearfield responses of woofer and vent (and baffle simulation):



I pimped the woofer with an additional fat neodymium magnet to push the data in the fundamental somewhat and to increase the stability of the magnetic field at lower frequencies by further saturation of the rear pole plate, the untreated SB has a weakness there.






According to my TSP measurements, the force factor increases by approx. 7-8%, which has a positive effect on the overall tuning according to simulation:



My mic distorts with a lot of k2, but here is a Farina sweep of the woofer in the box in 0,5m distance with the added magnet:

Last year I designed a single 18 inch cabinet for the (relatively) new Faital Pro 18XL2000.
The result was a compact (for its performance) single 18" cabinet with a measured F3 of 32Hz and outer dimensions of 52x65x75cm (without wheels).
To keep portlosses low, the port area is almost 0,5 x Sd.

Its possibly suitable for several other drivers (strong motor, large xmax).


REW outside measurement:



Link for the 3d file:
https://drive.google.com/file/d/1fnq_1bcXvzdAuWz-he1j3bfjDSR7xagp/view?usp=drive_link

Hello! I have a Logitech Z5500, and I really like it, but recently it started having an issue. The Pod is getting very hot at the back, reaching around 70 degrees. The component that's overheating is the one marked in the photo, and this causes the Pod's display to stop showing descriptions, leaving it blank. When this happens, I just leave it turned off for a while, and the display starts working again.
I’d like to replace this part myself. I know it’s a voltage regulator, but I don’t know the correct specifications to make the replacement. Could someone tell me the exact model?
If anyone has experienced this or something similar and knows of a solution, I’d really appreciate the help. Thank you!

Hello, my name is Igo. I’m Brazilian and currently living in Brazil. I’m here to seek some assistance with a Logitech Z5500 Home Theater that I’ve had for quite some time. I’ll also do my best to contribute and help this community whenever I can.

If the windings of the transformers are kept in 'common phase' orientation, is it ok to vertically stack two identical Toroidal transformers?
The transformers are to be wired in series and both will have identical loading.
Any advise would be greatly appreciated 🙂

After a long time that I stashed some 2sk182es sits I decided to use them. So the last year I did a small prototype pcb following Pa`s Got Vfets? schematic and it looked like this



The sound was nice so I decided to draw a pcb.





The Sit sounds nice and measures nice too




So after a while of playing with the Sit I replaced it with a power jfet(Sjep120r100) and the irfp150 mosfet in the ccs was replaced by 2sk3497.
The sound was very similar but I liked it a bit more. It is measuring a bit better too.





And the jfet/mos combo played music for quite a while. At the end of the last year I found some puck mosfets that I had unused from another project and wanted to try them.
So I checked all of them for vgs @3A and heated to 55C.



Initially I replaced the power jfet on one pcb with a puck mosfet and did some measurements. It was nothing spectacular but I decided to draw a new pcb to use them. So I drew the pcb but unfortunately didn`t have the funds until now to proceed with the components order.
So now that the sun went up and the components jumped from all over the places 🙂 it was the time to build the puck version.
This version doesn`t use Pa`s optocoupler to regulate the bias instead it uses lhquam idea of using a bjt comparator.
So here is what I come up with:



All good until here and even better from now on.
I had the pleasant surprise to find out that these pucks are doing better than the sjep120r100 and 2sk3497 combo. Beside that these(sjep120r100 and 2sk3497) are very hard to source and are very expensive too.
Here some measurements





I call it sePP because there is an onboard trimmer that lets you adjust how you want the amp to work, se or pp.

If there is somebody interested about this I still have some pucks to sell together with the pcbs.

The actual pcb can be used with sits too, I will test this someday...when time comes.
I drew also a smaller pcb that doesn`t host the upper mosfet and the output coupling cap being specially designed(for a friend) to be used with sits. Unfortunately I didn`t order this one and I am not sure I will ever order it.


A big thanks to Pa, ZM and lhquam.

Hey Now,
I've resourced this forum for quite some time and decided it was only appropriate to go legit.
I love all things Elekit and likely got the last of the initial offering of the new tu-8888 mono blocks.
Currently I'm running a tu-8600 r with newly installed WE 300b's. A great amp that will only get better. Had Genelex, which were good, but the WE's are amazing right out of the box.
I'm looking forward to assembling those monos and getting hold of a TU-8500 or 8550 in the near future. Lot's to look forward to in '25!

Hi, All! Came here because I'm helping a friend's live event biz get off the ground and am weighing the idea of building some custom speakers for it at some point. But I also love scrappy ingenuity and DIY solutions for niche tastes, so I might just stay for the discussion regardless of how the aforementioned project goes. 🙂

Looking forward to meeting you all!

I repaired this amp, or so I thought. I have replaced the fets and every one of the 1a, 2a, and 5d transistors.

The issue is, on one of the channels, anything below 15hz or above 30hz there is a strange audible distortion. I have included a pic of the wave form with the distortion.

I am a 51 year old man from southern Finland. I have many hobbies but the most important ones are hi-fi and motorcycles. Music is a big part of life but only listening, with the guitar I am an eternal beginner. Good versatile skills, I am a self-taught multi-skilled person. Cars, motorcycles, metalwork, mechanics, electricity and electronics, computers, renovation etc. Unfortunately English is not my greatest strength, I have to use Google Translate.

Equipment list:
Amplifiers DIY SE/84 tubeamp and Yamaha R-N800A
CD player Yamaha CD-S300
LP player Pro-Ject Debut III
DAC Topping D10s
Speakers Klipsch R-26F
Headphones Sennheiser HD560S

Note: this curve tracer project has a come a long way, and is now called pypsucurvetrace. This thread is for documentation, development, and discussion PyPSUcurvetrace.
There is a small website with links to the documentation, the code repository, and this thread.

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

I recently was looking into curve tracers for power transistors. I want a setup that allows straight-forward and automatic interfacing of the curve tracer to a PC (for data acquisition and also for instrument control). While there are a few testers available for small-signal transistors, those devices don't seem very useful with power transistors.

So... I was sitting in my workshop, fiddling around with my Voltcraft PPS bench power supplies. I remembered that these PSUs have a USB computer interface, and it's actually not so difficult to talk to these PSUs via USB. I have used the PPSs at work with a little Python program that sets current or voltage limits, and reads the true voltages and currents from the PPS. The readings are surprisingly accurate (as confirmed with different DVMs). The different PPS models have different voltage and current limits, but most models will have no problem to torture a power transistor.

The idea would be to use two PPS PSUs with a computer to determine the voltage/current curves of a transistor as follows:

• The first PSU provides the voltage across the transistor and the current flowing through the transistor.
• The second PSU provide the voltage applied to the gate or base of the transistor.
• The computer sets the gate/base voltage (second PSU) and then traces the curve for this gate/base voltage by varying the voltage and current current limits at the transistor (first PSU).

I am pretty sure it would be straight forward to scan the U/I characteristics of a power transistor this way. However, the process would be rather slow (say 1 second per data point or longer), because the communication between the computer and the PPS is slow, and the PPSs are slow in setting the and reading the voltage and current values. I guess it might be tricky to keep the transistor at a sufficiently constant temperature during the test sequence. Do you think this might be an issue? Do you see any other issues with my idea?

Hi,

I would like to measure the quality of alternative power sources for my solid state monoblocks (Spectral DMA-500). These amplifiers have the rise time of less than 225 nanoseconds and a slew rate of 1200 V / microsecond - they need a lot of current fast. The current transients for my entire audio system during playback of music with loud audio transients are as high as 25 A, at 120 V, measured with the time resolution of 40 ns.
Unfortunately, my mains power is compromised with THD of 5% and DC offset of 70 mV; it might also be limited in other ways. So I am looking at alternatives, such as a power regenerator (eg, PurePower+ 3000, which relies on a DC/AC inverter with a battery).

I would like to identify the best power source for my amps by measurement. I imagine a key tool for this purpose is a good oscilloscope (eg, Siglent SDS3104X HD), with sufficiently fast probes whose time resolution is much better than the amp's rise time (eg, differential voltage probe DBP150A and current probe 6030A, with time resolutions of a few ns).

I am inexperienced and naive, but I imagine the following measurement and analysis process:

1. Play a short audio file with powerful and fast transients (eg, drums).
2. Measure the voltage on the amp output, with a resolution of a few nanoseconds (which is much shorter than the amp rise time).
3. Possibly also measure the voltage of the audio signal on the amp input, instead of using the source audio file itself, to eliminate the playback hardware before the amp input from consideration.
4. Quantify the correlation between the audio signal and the amp output voltage.
5. The power source with the highest correlation is the best power source.

This test would presumably not allow me to determine if any of the tested power sources are limiting the amp performance, but I would know which alternative power source is best. Regardless, I worry that the proposed correlation is a bad proxy for what an audiophile would consider a good amp?

Should I also do other measurements? For example, should I rank the alternative power sources by the amount and speed of the current they can provide? Alternatively, should I rank them by the speed of change of amp's output voltage (or current?) How do you pros measure the quality of amp power supplies - are they applicable to ranking external power sources? I am guessing that some parts of the power quality analysis by the proposed Siglent oscilloscope could also be useful? Are there specific audio test tracks, perhaps generated with a waveform generator, to extract more information from the measurements?

I would be grateful for any comments or pointers. Anything I should be especially careful about?

Thank you very much!

Hi all,

There is Denon's SACD mechanism inside the Mcintosh MCD 1100 and it is failure. Does anyone know which model this mechanism belongs to?

Has anyone repaired this Denon CD mechanism before? If so, can you please share the model number with me? May be I can find the circuit diagram and fix it no loading unloading problem

There is no detail about the CD mechanism in the MCD 100's service manual.

Just realised that I’m short of 2x LTL-4231N LEDs to complete my XRK Smooth Like Buttah PSU build - anyone got a spare pair of general purpose LEDs they could send over to me, doesn’t need to be LTL-4231N or green, I’ll take whatever.

I just don’t want to pay silly postage for such small / low cost items!

Thanks

Dear everyone I am Thomas, 23 years old, from the Netherlands and very happy to join this forum.

Music has always been a big part of my life, and in the last 5 years or so I have been getting more into improving my listening experience through better equipment.

My first experience with this were the Koss KSC75s, which I think some people may be familiar with.

As far as headphones go I am currently happily enjoying my Sennheiser HD560s headphones. My loudspeaker setup on the other hand leaves much to be desired. Which is where this forum comes in. I kinda found myself in the ownership of two 25L enclosures with 8" speaker holes in them, that I am looking to fill. So you will probably find me on the forums lurking and asking questions on this subject.

Whilst I am not necessarily looking to make speaker building my next big hobby, I am looking forward to interacting with all of you and would like to wish everyone reading a nice day.

Kind regards, Thomas

I already built a 3 ways loudspeaker , but I detect some vibrations on the woofer cabinet.
So , I hesitate to build new cabinet , to remove this problem , and apply some small improvment.

Can anyone tell me if this 3 pin din is a standard plug that I can order ? It appears to have a locking thread too .
The 15v dc power supply will be somewhat more difficult I suspect.
It’s for a preamp that I’ve bought.

I'm playing with x-over points on a speaker. Here are a few measurements off axis. One horizontally at 60 degrees, and three vertical. The angles were estimated by eye. The thirty and 45 degree horizontal measurements only had mild dips. Actually, the 30 degree measurement looked pretty smooth

My room is bare sheet rock, and has carpet on the floor. I was wondering if the dips might actually be an advantage. So far, I only have one speaker built, and I'm thinking about building the second. I was using this speaker as a center channel. I have several x-overs. This is just one of my considered designs. I'm not sure if I want to attempt an audiophile design with this, or a HT set of mains. I also have some Peerless tweeters with a mild horn, or waveguide that I could use, but I'll have to build two boxes if I go that route.

The on axis isn't shown, but was pretty flat.

Hello all,

I originally posted this in the "introduction" section, but wanted to share this collection with the community in the main tube amp section. I requested a re-post from the moderator and he/she gave me the go-ahead. So here it is! I hope you enjoy!

Hope you are doing well! I look forward to exploring this community. I am a local guitar amp tech in Greenville SC.

I have been working on amps for a few years now part time. I've learned alot and always enjoy a challenge.

I was recently contacted by a Widow out of Wahalla, SC. Her husband was a Tube amp enthusiast. I went there with not much Money in my pocket, and when I realized the quality of the collection, I informed her that I could only afford pieces of it. She then stated a price that I could not refuse. After a trip to the ATM, we started loading up the collection.

It is... incredible. I've never seen such quality engineering in my life. These pieces (amps) look as if they came off of a factory line. Every wire is so cleanly soldered, and each design appears flawless. I'm using them actively as well, and they add a really cool aesthetic to the room.

Here are some photos of these Amazing pieces:

1. This is the Green God. It's a small output EL84/6BQ5 powered Hifi amp that I use for my CRT Tv's stereo (since my old 1973 CRT Chromacolor sound board went out). It has a 12ax7 preamp.. which may have originally been a 12at7. 6ca4 rectifier I believe... though I could be wrong. The tube does not have any markings showing the type of rectifier it is.






2. Next is this Black Beauty complete with transparent underside. I have not tested this one. But it has a 2 dual triode 6eu7's and quad EL84 outputs.



3. Next is the "Alien Amp" which uses an 832A POWERAMP. I've NEVER seen this type of power amp before. Apparently each tube has two anodes, so it's kind of like have a quad. The preamp is composed of two 12at7's. Trusty old 5u4 supplying DC.


4 & 5 Next are 2 KT88 Hi-Fi amps I have. They appear to be identical. One has tubes. The other doesn't. I believe the preamp is composed of 6SN7's.. again, tube rectified, this time a 5y3.



6. The next amp is what I call "The Beast". I cannot guess the wattage... but am surprised it's not powered by a Quad considering the output transformer and power transformer size. I have NO IDEA what type of tubes this takes. I'll need to take off the bottom and find what the tube pin-out's are and compare them against known data sheets. It appears to have two inputs.



Also... what is that tiny circular screen??

You can see the amp has a rectifier, one preamp tube, and two power tubes.. probably KT88 or potentially KT120.

I also received alot of parts.... High end EDCOR transformers of all sizes... Dynaco transformer pairs... Tubes of both NOS and new name brand excellence.

I have the parts overflowing on 2 four tier shelves. I've sold a few desirable tubes that I've found.. but have kept the rest because it's such an excellent collection.




The builder's name was Michael Werner... I'm sure he was on one of these forums.. Do any of you know of this builder?? Perhaps there are threads that encompass the details of these builds??

Let me know.

Thanks for letting me introduce myself!

-Low

Hi,

I've designed a power supply for a mic preamp I'm building. The circuit is taken from Douglas Self's 'Small Signal Audio Design' and provides +-17V rails for op-amps and +48V for phantom power.

I'm intending on mounting it in this enclosure https://www.enclosuresolutions.co.uk/product/513-0900/ .

Mains power entry will be via s switched and fused IEC socket, connected to the board using Faston connectors. The outlet will be on a 5-pin XLR, carrying the 17V rails, the 48V rail and two ground wires, one for audio, one for power, connected to a star ground on the chassis.

The bridge rectifier will be mounted underneath the board and bolted to the chassis, hence the hole in the PCB. The regulators will be done in the same way. Do you think this will provide enough heat-sinking for the regulators?

Do the circuit and PCB both look sensible?

Thanks,
James

Found some 3d printed goodies for breadboarding.
https://www.thingiverse.com/search?q=agalavotti&sa=&dwh=195a5bb2e8d8f39

I will include direct to authors page if i get permission


email address on authors site is dead. Seems he is a member here last seen back in 2022.
memner name is agalavotti web page is on altervista.

Hi Folks,

Merry Christmas and Happy New Year to all past, present and future Aspen customers!

It's been a wild ride for 2024...... Russia/Ukraine war, Israel/Palestinian war, collapse of Syria, China rattles the Taiwan sabre and experiences financial (real estate) issues, US Britain Italy and Argentina change government, rise of India, rearmament of Japan, eruption of world currency inflation. It appears the only staple of the world is change itself.......

Through all this, the human condition has changed little; and our hobby continues for most of us, although we are tightening our belt since costs are quickly escalating.
I have sold quite a few amplifiers in 2024, and it's kept me stimulated and passionate about audio.

In 2025 I will enter my 75th year and still thinking clearly! Not bad for a guy who nearly died of a burst aneursym in 2012 for whom the doctors gave 10% survival! I live with the fallout of course, but I am still healthy and still work pretty hard. Luckily I live in Australia with a good health sector, although it's becoming more and more expensive to access care.

I have many projects on my books and suspect I may not finish all of them in 2025. But I continue to work with the best of them; and in truth the Alpha Nirvana 39W Class A has been picked up by VeraFi in Texas and will be on sale mid-2025.

I have many friends here and wish them a successful, healthy 2025. Life goes on, love of music and the technology continues, and every decade brings new and interesting technologies. We can enjoy all sorts of fascinating subjects in the world on YouTube, and I have to say that my last twelve years have been my most productive and enjoyable in my life.

Cheers,

Hugh R. Dean
Melbourne, Australia

New poster here, but a long time AK denizen. Wanted to say hi, and since this is a requirement before posting any technical questions, well...Hi!

I've been working on audio gear since around 2000...started with basic recaps of working gear and have delved into bringing back non-working gear. Mainly Solid State, but have done some work on tube gear. I have no formal electronics background, and limited test equipment, but have learned a bunch over the years and have had many successes. Unfortunately, a couple have me somewhat stumped, and due to the lack of information I can find (especially one piece) or the poor-ish quality of one service manual (combined with my lack of circuit knowledge), I haven't quite figured them out. Anywho, full-time job takes me out of the country for a day or two (usually weekly), so I end up having a start-stop-start-stop sequence of working on the gear, some projects dragging on quite awhile due to that and family obligations. Lots of other hobbies too....homeowner DIY, photography, coffee roasting, beer brewing, etc.

I've come across many Google-search posts linked from here, so I know the community is active and well versed. I just hope I can bring something to the table too.

John

I signed up here because of this thread: https://www.diyaudio.com/community/...dio-interface-for-vinyl-a-d-archiving.349315/

In is some audiophile Naysayer is going on about bandwith and hearing ability. I see these discussions all over the internet and the naysayer is always touting the same thing. That the human ear cannot hear 96kHz or 192kHz etc. etc. But those numbers refer to "Bandwith". Hearing is "Frequency Range". So I will go on to read the rest of that thread as I am interested in a Phono to USB solution that goes at least up to a "Bandwith" of 24Bit 192kHz. I was unable to respond directly in that thread as this is my first post and apparently I can't respond to a post unless I first create an "Introduction" post? So below was my attempted post in the beginning of that thread:

Why do People in these conversations always confuse "Bandwidth" (Amount of data processed within a given window i.e. 24Bit / 96kHz) with "Frequency Range" (The lows and highs within and beyond audible hearing). They are 2 completely different things. One eg. 24Bit / 96khz has to do with how much detail is in the music. The amount of detail on vinyl far exceeds the amount of detail available on a CD. In fact I don't even understand why CD's were ever called "Lossless" since they are compressed in order to fit onto a CD with it's maximum "Bandwidth" capability of 16Bit / 44.1kHz. Frequency range 20hz to 20kHz (Maybe till we reach 12 years old or so), etc.. Is a completely different calculation and has nothing to do with "Bandwidth". It is not the "Frequency Range" that is missing on a CD. It is the detail in the music that has been removed in much the same way as it was (Or is I guess) For MP3's and other lossy formats. Please get your terminology straight and stop confusing the two when you are attempting incorrectly to say that CD's are superior or even equal to Vinyl. They aren't.

Hi folks.

Im looking at moving these on. They're not that old and probably just about run in.

I bought them boxed and "as new". I ran them in properly before fitting them in the Pensil 10p cabinets you see pictured.

I'd be happy to post the drivers or sell them as collection only as complete speakers.
The cabs are properly made and have the correct stuffing in them, wired with Van Damme Blue series.

Drivers alone would be £140 the pair.
Add another £100 for the complete speakers.

Collection is from Warrington, UK.

Hello,
I just thought of something and wanted to ask the computer guys if something like this is possible.

I gave my brother an R2R DAC for Christmas.
It was an entry-level model, but it's an R2R Ladder DAC for 160,--

Working with my DSP, I thought that if I had three of the inexpensive DACs and could connect all three to a computer via USB at the same time.
Then I would have an high-end 6-channel R2R DSP...and could drive a pair of 3-way speakers.

So I have no idea if there is a software that can simulate a crossover and then separate the music and deliver the individual channels to more than one USB socket (or Coaxial, Opical aso...)
What do you think about this idea and if you have ever heard of something like this?

It is simpler than I thought to make it oscillate. Imaging putting 2 feet,1uH cable in front of the output transistor and a tinny capacitor at the output, congratulation, you've got an oscillator.



This might be what is happening.
The circuit make it a Colpitts Oscillator. Please see the detail analysis from: https://en.wikipedia.org/wiki/Colpitts_oscillator

C1 could be just the internal capacitance from the transistor.
C2 is the capacity load at the output of the emitter follower.
L could be the cable run from the input.

我是来自中国青岛的"发烧友“杨金明。此前一直使用Windows体系安装的Foobar2000播放音乐;但是有极大的局限性，声音有上限。先生：我有个比喻：我们去远足旅游爬山，到了荒郊野外，需要携带一把综合性能的“瑞士军刀”，她即可以削水果、也可以修剪指甲、还可以用启子开罐头、再可以用螺丝刀维修汽车；面面俱到，啥都能行。现在假设回到了家里：切菜水果用专业的熟刀，剁肉却要用生刀；越专用越高级。Windows就是像瑞士军刀，无所不能，却并不专业。听音乐更是需要极致专注的设备和软件。偶然看到论坛上有介绍symphonic mpd，非常极致的专业，这主要取决于 kernel 的 latency 是否超低;特别欣喜的是对Xenomai 4（EVL）的加持
这简直是对我量身打造一款神器。我家里的器材大致介绍一下：扬声器采用丹拿的弦歌典藏版0591号，功放是前胆后石一体机意大利百宝仕古典一号（一对左右桥接单声道），解码器使用广州产的“龙船铜壳8X9039芯片组”，笔记本目前用SONY型号PCG-31211T（明年升级为华硕ROG枪神版）。

Hello guys!
I'm interested to add an analogue source to my music setup. It will be a vinyl. 🙂
Not bough yet a turntable, but it will be with MM head. I want to build my own tube phono stage just because I recently got some interesting tubes.
I've spent a few weeks in web research trying to arrange my tubes and select appropriate. 🙂 I believe the time was not wasted. I read many articles and reviewed many schematics...
Finally I decided to develop some mix of all ideas that I've found. Output stage is a mu-Follower, I choose it because of low output impedance.
Here is a schematic of one channel:


Also I did a PSU simulation:


Hum rejection ration is about 90dB as you can see in this screenshot. Of course in real device the numbers will be smaller.
Any suggestions, enhancements?
Thank you in advance!

Hi,

I have several drivers for sale, some new, some with optical issues, all working and of course tested.
All drivers located in Northern Germany, but shipment is possible.

I will add photos and info 1 by 1.

First up is a pair of Acoustic Elegance Dipole 18-8 from 2016.
Technically perfect, some small signs of use (slight colour tint on rear poleplate from magnet mounting, labels gone while cleaning) visible.
Photos and measurements attached.
Drivers are in the EU, VAT and duties paid.
Reason for sale is ownership of a pair of Fertin Acoustics 18" fieldcoil drivers.
When they arrived at my door, the Diploe 18 were around 1550 € including shipment and VAT.
I therefore think that 800 € for the pair excluding shipment is a fair price.
Original boxes are included, so shipping is no problem, though not cheap (2 boxes 23,5 kg each).

All the best

Mattes

Hello, my 9028 Pro sounds great with DSD512, IIR set to 70K and LL1676 transformer (1:1) summing the outputs to an 01A tube.
Question: since the LL1676 already low pass filters the output (53KHz corner frequency), is it possible to disable the internal IIR filter in the DAC chip? I have a 4-position rotary switch on the DAC to select the IIR and 70K clearly sounds better than a lower setting, so maybe it would sound even better without any IIR filtering. Just a thought...

Hello,

I want to operate two IRS2092 amplifiers in BTL mode. Both are on the common board and have a common power supply. Each has its own VCC. The BTL inverter opamp also has a separate power supply +/-15V. If both amplifiers are connected separately with the speaker to GND, both play excellently. They are able to deliver 2x 400W 8Ω (+/-80V). The problem is in bridge mode. With an 8Ω load in BTL it reaches a maximum of 100W, then growl and pulsate. as if the amplifiers are arguing. With a 16Ω load everything is fine and the power goes very high. Why is there a problem with BTL at 8Ω? Thank you for every comment. I am attaching a schematic of one amplifier. The second is identical.

Hi was a member but havent contributed much hence was advise to introduce to reply to post

If you're using basic tools like me, the simple best piece of advice I can offer is the above.
Last night I decided to make a simple TT isolation plinth. Literally a rectangle piece of ply with 4 sides to make a shallow box.
I cut 2 of the sides to completely the wrong length and because I rushed, they were all a little bit different in height +/- 1.5mm
I've glued it all together anyway and it looks like one of Homer Simpsons projects.
DO NOT RUSH

I am looking for a microphone to measure my two-way infinite baffle speakers for the Pass DIY biamp 6-24 crossover. Preferably calibrated, XLR and I'll use dual channel measurement so I followed @Bazabing thread https://www.diyaudio.com/community/...ntuitive-beginners-measurement-set-up.393744/ with interest.

Cross-Spectrum's calibrated Dayton EMM-6 microphone would have fitted the bill nicely at $75, but as they don't ship to the UK where I am based it isn't an option.

That leaves the next two contenders: the Dayton EMM-6 at around £96 ($121) on Amazon, or the Beyerdynamic MM1 at £185 ($233) both with a factory calibration.

The MM1 is quite a lot more expensive for one-off project. Which would you pick, and why?

TIA

John

I am selling 2 high quality Hypex PSU modules. These are 2 x Hypex SMPS1200A700. I bought these babies to power a pair of DIY monoblocks project that I could never finish due to lack of time.

These beasts have plenty of clean current, their speed in transients is above all. It supports UcD and Ncore class-d modules, but I think this stuff can make a difference even in non class D projects.

I'm asking 230€ for both, basically half the price, although my modules had little use.

Hello I am HawkAudio from Venezuela 🇻🇪. This is one of my favourite circuits of amplifier to build. I have called it The Loyal Amplifier because it is a circuit that always have worked to me.

Nice to be part of this group. Interested in building speakers and learning from all the experienced DIY’s. Also, looking for advice on new components/parts to use on future upgrades/mods.

Recesses for flush mounting speaker drivers are best made by a router.
There are 'palm routers' for sale on ebay and Amazon at a low price, about £35, and router jigs to fit are available for about £15, so I had a go.



I did find two problems which were fixed as below.

First, the vertical movement is not positively fixed but only held by friction. It is necessary to hold the device by the grip (low down on the body) to avoid pushing the cutter too deep. Even so, and with the clamp tightened hard, I still found (in my testing) that the depth could wander. This was fixed as below.








This shows a short length of dowel resting on a screw head at the right and engaging with the edge of the slide, fixed in place with insulating tape. I used one each side. Worked a treat, no movement of the slider.

Next problem was that the jig did not go small enough for the 176mm diameter of the bass speaker unit. See below.




See the black slider in the track. At its left hand end I made a 3mm hole which you can see; it means the left hand clamp screw cannot be fitted but I had no problem. This hole allowed the 176mm diameter recess to be cut.

For the tweeter, much smaller diameter:
In the above photo, at the bottom right corner of the base plate you will see another 3mm hole I made. I measured the position knowing I would get close but not right. No problem; as you see I fitted only two of the plate fixing screws which allowed the plate position to be adjusted slightly. It was then necessary to drill through this hole and through the plastic above it to allow the peg to be inserted from above. It all worked.

OK, not elegant engineering by any means, but the results were excellent and the price was reasonable.
I hope you find this useful.

Hi folks,
This schematic is from one channel of my Cary pre amp.
Would it be possible to not use both outputs from the two 12AU7s in parallel but insead use each of the second outputs to duplicate the basic circuit for a differential application?
Since I am not familiar with tube amps I probably fail to see the necessity of the paralleled tube output.

classic german highend studio modules

hey folks,
if someone likes to use the classic german studio modules, form Lawo, BFE, Delta, Neumann, etc., let me know..
I have a lot of this parts, like amps, equalizers, relais cards for crossbars etc. and .......
With this modules you can build a lot of different gear, like mixers, control amps, preamps with an absolute high sound quality.
Nearly all modules use high quality audio transformers form Haufe or Pikatron.
All for 24VDC power supply.
For nearly all of this parts the schematics are available.

regards

HP

No longer available.

Here is something different for a change:

It is a small, unassuming amplifier project, but with some unusual features:
It combines a circlo output topology with an active bias servo.

The servo stabilizes the quiescent current, but it goes further: it actively controls the output stage so that both sides always remain active in a "warm" class AB, having most of the attributes of the full class A, including a complete absence of crossover artifacts.

It is extremely easy to build, offers excellent performance even with 2N3055's, requires no adjustment, no matching, no thermal compensation and yet has a rock-solid thermal stability.

It is also incredibly healthy, and behaves gracefully, even with loads lower than 2R.

In short, a nice little amplifier, not in the top-class, but with excellent all round performances.

Meet the Circlophone©!!!

Hi I am looking for a schematic for this amp or equivalent Audison AV 5.1K. This amp has 2 494's, and I don't have no voltage on pin 12 of either of them. Maybe someone in here has had a little run in with this amp.

Hello

In the last month I've been working on a custom digital interpolation FIR filter implemented on an FPGA. This filter does pretty much the same thing as well known DF1706, SM5847, PMD100, and so on. However, its ability to reconstruct and attenuate a signal is way beyond those 🙂

The filter contains 8192 coefficients and it interpolates the data by a factor of 16 times (e.g. 44.1 kHz to 705.6 kHz and 48 kHz to 768 kHz). It has several FIFOs built in since its core is running asynchrounsly (at 225 MHz) while the MCLK is used only to clock data out of FIFO and to create LE (latch enable) signal for the DAC.
In fact, this filter does always interpolate to 705.6 kHz and 768 kHz (an integer factor of the input) and accepts data up to 768 kHz / 32 bits. In order to do that it works like a sample rate converter, so it interpolates and decimates at the same time. However, it should be noted that for 44.1 kHz and 48 kHz it does not decimate at all, but for anything higher than 44.1 kHz and 48 kHz it still interpolates data 16 times, so e.g. having 96 kHz input means that the data is interpolated up to 1536 kHz, but decimated back to 768 kHz. The same goes to 768 kHz input which is interpolated to 12.288 MHz (in a mathematical sense of course) and decimated back to 768 kHz.

It should be noted that along with huge amount of coefficients (8192) this filter incorporates multiply-accumulate units of 32x35 bits wide. It means that the input data word is fully accepted up to 32 bits (without any truncation for that matter) and coefficients are quantized on 35 bits resulting in unmatchable accuracy of the math it does to calculate the output sample 😉

In the title of this thread I did mention you can drive PCM56, PCM58, PCM63, AD1862, AD1865 and so on up to 768 kHz. How is that possible? The filter contains a self reconfiguratable oscillator which sets its frequency depending on the output length (16, 18, 20 or 24 bits). It means that the output bit clock (CLK) is running fully asynchronously from the LE (latch enable) signal which is generated by dividing the provided MCLK signal, so data is latched in almost all DACs without any extra jitter introduced by the oscillator itself. In fact, the filter contains 3 sets of FIFOs (6 FIFOs for both channels) - one in its input (I2S) before going to the core, another one on the core output and the last one for the final oscillator to clock data into the DAC. Besides all of that this technique introduces a quiet zone after the latch signal going down, so it should give DAC some time to settle down with its output before clocking in another sample 😉

Depending on the word length the following frequencies are created on the CLK output:

16 bits - 14 MHz
18 bits - 15.5 MHz
20 bits - 17 MHz
24 bits - 20 MHz

It means that certain DACs such as PCM56 and AD1865 will be running at the edge with 768 kHz stream, but they will work just fine according to my tests. The LE (latch enable) signal is always 705.6 kHz or 768 kHz depending on the input (either multiply of 44.1 kHz or 48 kHz).

0 dBFS @ 20 kHz:



-60 dBFS @ 1 kHz:



Jitter test @ 48 kHz with LSB toggled @ 250 Hz:



Filter attenuation (linear phase) - white noise @ 48 kHz:



All measurements were performed using PCM58.

The filter has I2S input with signals of MCLK, BCLK, LRCK and DATA. However, MCLK can be fed by the same source as BCLK signal (if no MCLK is available) assuming that BCLK has a rate of 32x, 64x, 96x, 128x Fs or similar since the filter has to determine its frequency to know how to divide it in order to create LE (latch enable) signal. Any exotic values of BCLK rate will not work as MCLK, so keep that in mind. The jitter and synchronization of FIFOs depends purely on the MCLK signal, so in the long term it needs to be synchronous with LRCK (in almost all cases it is, since BCLK and LRCK should be derived from a divided MCLK clock).

Following frequencies are supported as MCLK:

49.152 MHz
45.1584 MHz
36.864 MHz *
33.8688 MHz *
24.576 MHz
22.5792 MHz
18.432 MHz *
16.9344 MHz *
12.288 MHz
11.2896 MHz
9.2160 MHz *
8.4672 MHz *
6.144 MHz
5.6448 MHz
4.608 MHz *
4.2336 MHz *
3.072 MHz
2.8224 MHz
1.536 MHz
1.4112 MHz

Those with asterisk are usually used in CD-Players and it should be possible to use the filter within a CD-Player once input is attenuated using 170 Ohm or so resistor per line (in order not to damage the FPGA and its I/O pins due to 5V logic levels). The filter can be powered by an external supply (5V or higher) or by providing a direct 3.3V power supply (it is up the user).

Following outputs are provided by the filter:

CLK - clock for data
LE - latch enable signal
SD_L - serial data for the left channel (and its inversion with the line above it, so you can create a differential DAC for XLR outputs)
SD_R - serial data for the right channel (and its inversion with the line above it, so you can create a differential DAC for XLR outputs)
3.3V - main power supply
GND - ground

It should be noted that the filter does have a TDPF (triangular probability density function) dithering algorithm as well. It can be turned on or off by a jumper depending on your preferences.

The price for a fully assembled and ready to use board will be 250 EUR.

Final revision of 16x interpolation version:







ROM jumper selects which type of filter should be loaded during boot process. There are two filters available, one is linear phase and the other one is a minimum phase 🙂 Both of them have 8192 taps.

The filter can be directly powered by an external USB to I2S converter, but it draws about 300 mA of extra current, so keep that in mind. Also, it is a 4-layer PCB. Dimensions are 50 mm x 47 mm.

For more information and orders please visit:

Digital Interpolation Filter (FIR) - KuSy Audio

I am rarely available on forums nowadays, so a friend of mine will take care of your questions.

For sale is my RJM Emerald phono stage (https://phonoclone.com/diy-pho7.html) -- $300 OBO

At $300 I'll pay shipping and PP fees.

I have built another Emerald with some different components so I am selling this one.

This is a wonderful sounding preamp. This Emerald replaced a Schiit Mani 2 in my system and it wasn't even a contest. This Emerald was compared against the internal phono stages on a Rogue Sphinx II and III and was more musical and quiet. I also compared this against a Simaudio P5.3, I preferred the Emerald my friend preferred his P5.3.

I build it per the RJM BOM but with a couple of modifications:

Power supply

• 30VA R-core transformer
• LED power switch
  • DC converter for power switch
• CRC DC filter
• Neutrik PowerCon for umbilical

Signal Chassis

• Neutrik PowerCon for umbilical
• Neutrik RCA jacks
• C3 - 1.8uF Clarity Cap SA
• RJM Switch Board for cartridge loading
  • (1-4 all open) - 47 kohms or whatever the phono stage input impedance is.
    -------
    close 1 - 1k
    close 2 - 221 ohms
    close 3 - 100 ohms
    close 2 and 3 - 68 ohms
    close 4 - 22.1 ohms
    -------
    (5-6 both open) - 0 pF (+ cable)
    -------
    close 5 - 100 pF (+ cable)
    close both 5 and 6 - 200 pF (+ cable)
• Vampire one piece hard brass ground post
• Installed are OP27 opamps
  • Can be rolled with many different single channel opamps

Umbilical is approximately 12inch but it can be easily lengthened because of the screw terminals in the PowerCon connectors.

Cases are from China off Ebay.

Thanks for looking!

Some of you may know I built a ball bearing linear arm. However, this kind of linear arm excels with low compliance cartridge and requires high VTF to do the job right. My ball bearing arm does sound wonderful with Denon DL-103R(VTF=2.2, low compliance) after fine turning, especially for jazz. Bass is excellent. Denon DL-103R usually exhibits some shrillness in high frequency, but not on my linear arm.

In my opinion, ball bearing linear arm works better with high VTF and low compliance cartridge because two reasons.

1. Heavy moving mass. In most cases, there are no too many options to reduce moving mass.
2. Ball bearings have simply too high friction for high compliance cartridges.

So, the answer is to get ride of friction in order to use high compliance cartridges. Frictionless air bearing becomes the only option.

For air bearing, the most difficult part is air compressor, specially for New Way air brushing kind of arm because it requires high air pressure. The higher air pressure, the stiffer the arm is. I used a small fridge compressor to build quiet air compressor. The end result is excellent. It runs very quiet. In my listening room, the noise level is about 25 db in night. I measured the air compressor noise level. It doesn't even register on the sound pressure meter. The noise level is just same as a small refrigerator. I also add two cooling fans. These fans bring noise level up to about 30 db. It is no problem for me because I put the air compressor in the closet. I can hear nothing on my listening seat.

Please see attached my diy air compressor diagram. My compressor has two zones, high and low pressure zones.

1. Air Filter. It prevents small particles into the air line.
2. Compressor. It is small fridge compressor. In my case, it stops for 30 mins and runs about 20 mins. The compressor can be a little more powerful so the run time will be shorter. But in my case, it is ok.
3. 1st Stage In-line Filter. I put it first because it is cheap and can easily be replaced.
4. High Pressure Regulator. This is 2nd stage filter with high pressure regulator.
5. Check Valve. Check valve permits air only going one direction because the compressor can't hold high air pressure for long time. It also prevents high pressure air goes back into the compressor.
6. Pressure Switch. Once the tank reaches 80 psi, it will shut the compressor off and turn the compressor on once it comes down to 40 psi.
7. Safety Valve. It is set at 125 psi.
8. Air Tank. I bought 10 gallon, but 5 gallon should be fine. Air tank will hold high pressure air. Whenever I want to listen, it will be ready. I bought the tank from Homedepot for $34.00. They sell 5 gallon for $30.00.
9. Cooling Fans. These fans are from my old PC power supplies.
10. Temperature Control Switch. I set the temperature at 70 F.
11. 12 V DC power supply for the fans.
12. Main Power Switch.
13. On/Off Air Valve. Juts in case I need to shut off the air to feed the arm.
14. Flow Control Valve. It slows down air flow so I can have low pressure air to feed the arm.
15. Low Pressure Regulator. It regulates air pressure in low pressure zone. It controls the pressure to feed the arm. It has filter too. The filter element is 10 micron.
16. 4th Stage Filter. It has even finer filter. .3 micron.
17. 5th Stage Filter. It is auto fuel filter. Its function is to prevent anything small particles into the air line.

I like my diy air compressor so much. It is quiet and runs cool. I don't think you can buy anything commercially available air compressor better than my diy air compressor even you may spend a lot of money. The total cost of my diy air compressor is about $350.

I have Lite DAC 38 using Burr Brown PCM 1704 R2R dac chips. It sounds beautiful analog and non fatiguing sound. I want to sell it cheap for $150 + $20 shipping within US. It is good purchase if some wants to use just the case and transformers. Local pickup in Chicago area also possible. Reach out to me on (630) 446-0165‬ for local pickup.


Kit itself is available for about $400.

http://www.analogmetric.com/goods.php?id=247

By now it has been a while since OPA828 (and OPA2828) were released. Any detailed comparison done (in the context of audio) to the opamp, OPA627, that they are supposed to replace? Thanks!

Hello everybody!

Is a simple first order lowpass filter "good enough" in front of an amplifier that drives a subwoofer?
Or do I need a higher order LPF?

I am not talking about "getting the best sound" from the system, I just don't want to damage my new subwoofer.
I am also not asking about optimizing the crossover point or phase issues and stuff like that.
Just preventing damage from occuring.

Shouldn't the inductance of the subwoofer itself cause low frequencies to be "cut off"?
Or would passing an unfiltered high frequency signal into a subwoofer cause it to heat up and burn itself out?
Is a filter needed at all?

I know a bit about electronics but almost nothing about speakers and how to drive them.
To me they are just "magic inductors that turn current into air-movement" ;-)

Usually I just try stuff to see if it works but I don't want to scrap my new subwoofer.

A bit more information about my setup:
This is what I want to do:


Yes, it is a badly drawn sketch but it explains what I want to do.
Use a subwoofer "in parallel" with an existing system that will be set to only do mid and high frequency.

The subwoofer I have is a Behringer VP1800S (please no anti-Behringer rants, thanks).
It is rated for 1600W maximum and has a frequency range from 40Hz to 200Hz.
The amplifier is built for the full audio range and can output 400W stereo, I will use it in "bridged mode" to get 800W and a single "channel".

I will never actually push 800W through the subwoofer, that would probably destroy everything around the subwoofer ;-)

Of course I tried to search online about using simple first order lowpass filters in fron of subwoofers but I couldn't find any proper information about the topic.

Any answers would be appreciated.

WTB

Please reply either here or by DM with details, condition, and asking price.


Greg in Mississippi

Hello,

May you advise me on high beta, high FT, NPN/PNP TO92 or smd please .

MPSA 018 and BC560 with beta around 500 measured for real seems interresting,

Anything better for audio ?

thanks

Hello,

Just wanted to introduce myself and say that I have been obsessed with all things home and car audio for sometime now. I don't think there is a cure for my addiction but hoping to find ways to deal with it by belonging to this forum. 🙂

Dan

Hello all. A year ago, I built this amplifier with Common Ground Collector output topology very similar to that used by QSC in one of its model called USA. A friend of mine gave me two boards which he ordered to make in China and he told me they both had an error which he had not been able to find out. After I fixed them, I mounted all the parts and the circuit was supplied with +/-55V.

For the adjustments, I just turned the null trimpot to set Offset voltage to minimum (0V). For Bias, simply turn carefully the bias trimpot until obtaining 80mV in one of the emitter resistors of the driver transistors and 160mV on both emitter resistors.

The amplifiers sounds very good 😀. I uploaded some photos of the amplifiers I made.