Hello there. I have a cheap chinese dac (D2-mini) and wanna experiment with different op-amps. Currently it uses 2 NE5532P as the I/V and a TL072 as the LPF.
Current planned replacement NJM2137D for the I/V and AD8066ADR for the LPF. The LME49720NA is disqualified as the LPF because its 5V performance is horrible, 1%thd+n at 2vrms output. I'm looking for any op-amp recommendation that is not super expensive.
Dac internals.

Just a little question.
Does a Golden Ratio ratio speaker box have greater capabilities for creating micro-details?
Or does it mostly depend on the speaker element used?
Does the volume on the speaker box affect the ability to create micro-details?
Does the tuning on the speaker box affect the ability to create micro-details?

Folks:

I have a reasonably old equipment stand consisting of black metal (either painted or anodized -- I can't tell) cylindrical struts and MDF shelves. I cannot recall the vendor and there are no identifiers on the stand. It's a very simple design, but it needs reconfiguring to accommodate a new project: struts in new lengths are needed.

The struts are 3/4" in diameter and the ends are tapped for 7/16" bolts.

Does anyone know of a supplier for black metal cylinders that are 3/4" in diameter, tapped for 7/16" and available in lengths of 10"?

Thanks in advance!

Regards,
Scott

Hello
I have some BT module, what output has i2s.
I need right justified, so i will use for it CS8421
But other problem is, that this module has HFP, and sampling for it is low (8k WS and 512K clock).
This CS8421 going to unlock state, when HFP is on.
I like to use before CS8421 AK4121 to up convert to min 44.1K sampling.
I know, that all will be up or down to 44.1k, but this way is it possible to connect to dac?
Normal i have 48K WS with 3.07Mhz clock (i thing 20bits), and HFP has 8k/512 (8bits)??
Is this AK4121 should up/down varius sampling to one?

Building a teeny Lm1875 chip amp, a Years Long shelved project , which I'm finally completing,
because I'm tired of having it as an unfinished adventure.
Have the usual Antek Tx . 15-0-15 (wanting + - 20v) .
Problem being I have One bridge on hand (and avoiding driving across town to buy a second one)
How do I wire the two secondaries together to only use One bridge.
Connect the two Green wires together as the - out put... OR ?
Thanks

A power supply choke good to over 300mA is expensive.

But I have a few pairs of 150mA chokes around. Would it be useful to parallel two 7H 150mA 140 ohm chokes to make the equivalent of a single 3.5H 300mA 70 ohm choke?

More importantly, is there a problem with this? (Other than the space it would take, extra holes in the chassis, etc.) Capacitance? Current sharing?

-=|=-

Hi,

I'm wondering what material people use for damping the internal walls of PA speakers? I've seen some graphs showing different absorption coefficients at different frequencies for some materials and am not sure what to go for.

Cheers,

Sal

hello friends...
someone please help me to build this amplifier. will it work ? what changes this circuit will need to work on 12 V Supply and substitute for 2N3904 and 2N3906 as i cant find them in my town. i have bc557,558 and bc547,548. can i use MJE3055 instead 2N3055? please help me friends.

here is the link

90 W audio power amplifier based on transistor - Amplifier Circuit

I have a Frank Hi.Fi. by (Stereo?) tuner manufactured in Belgium around 1961. I am looking for service data on realignment. There is no information plate on the unit, the only info is on the front panel.

Here is the only info I have on the manufacturer:
Mr Maurice Frank was engineer from Telefunken Brussels before the war, after the war he started up his own company "Radio Union" mid 50s he started with HiFi amplifiers and tuners.

The problem is, when tuning into stations you can get the left or right channel tuned in clearly, but not both. I am guessing that some form of realignment is required, but to do this I assume would require some data to work from. I live in Cornwall UK, (long shot) does anyone know someone in the area that does this kind of work?

Any help would be appreciated

Chris
I also have the matching amplifier. https://www.diyaudio.com/community/...ts-ultra-linear-stereo-tube-amplifier.368539/

Anybody has an experience with those transformers? . I understand that finemet is a kind of amorphous core material . I have to admit that Lundahl LL 1674 Amorphus input trans for some reason is not my cup of tea so I wonder if finemet Noguchi transformers have the same traits i.e detailed and airy but kind of missing weight in midrange and bass .

Hello everyone, can anybody tell me if it would be possible to make a balanced version of these. I do not understand the concept very well and would like to know how to wire them.

Looking at the fan following of the Ls3/5a why is it soo famous? The crossover also doesnt look like conventional 2nd order or 4th order.

What is this all about? It could be some BBC standard ok then so what? what makes the sound soo special?

Hi everyone.
I would like to discuss the following topic with you.
if on the same support portion of the loudspeaker where the coil in which the signal flows there was another electrically separate coil going to the amp or to the preamp or to the active analog line crossover (in differential mode) it could be obtained negative feedback and get equalization? .

The only schematic I can find for (any version) the Rega Brio is for the 120v power supply. I'm curious whether a 240v Brio from England has a transformer tap which can be used to convert to 120v operation?

Hi everyone,
I am wondering if anyone can give any advice about how to go about making a super tweeter to add to a full-range speaker system (a DIY ACI Alpha limited project that has a 37-18,000 Hz frequency response +/- 3db). I have read rave reviews of the Townshend Audio Maximum Ribbon Super Tweeter, but a couple grand seems kind of steep, and I was hoping somone on this forum might be able to provide a newbie with some advice about how to make something similar for a lot less money, i.e., possible ribbon drivers to use, how to design an appropriate cross-over, etc.
Thanks very much
Chris

Hi I’ve just bought a par of Decca London Ribbon and would love some help to build a nice speaker with the right filter, elements and box.


this is what I have now



And this is what I would like to have.

I am a real rookie so please help me out shase my dream 😁🔈

Have my first cmax 45ah bank and I have a power 650 mosfet 1992 rev. Is it capable of handling 15.2 volts with the battery charging that high? I was reading through the Power 300 manual and it says “
The Rockford Power 300 is an automotive stereo power amplifier which
will provide state-of-the-art sound in cars, vans, boats, or wherever a 9
to 16 Volt battery is available.” And if it can would it be recommended to be recapped/ gone through? Would be using it alongside a taramps bass 8k for a little loud daily. Or is 14.4 the highest?

Hy Everyone,

I`m currently repairing a STEG K2.02 Amp, with blown Supply MOSFET`s.
The MOSFET`s are STP80NF55-08, but they are nowhere in Stock.

Which substitute can i use, fits best?

Thanks in Advance!

Just finished building my kit, but only one channel works (left). Any suggestions for where to start?

Reading and reading some more. It appears I can just plug in a pair of 2a3's, set bias and go. Were are now set up for 45's with output trans. 5k@50mA?

I have a lot of old Dayton-Wright ESL panels, maybe 30 or so. Each is about 6 wide x 16 inches high.

So, I've been thinking about some kind of continuous wall of sound*. But I've been wondering about how to think about channels. Obviously, it would be simplest to have just two channels and two amps (and/or bi-amp'ing as needed for subs and maybe tweeters in each channel).

The simplest way is to just have 16 panels on the left with the left channel and 16 on the right with the right channel. That's conventional.

Then I thought maybe better sound would be 12 on the left, 12 on the right, and the middle 8 would still be driven by the L and R amps, but some reversed in position so as to put a bit of R just left of centre and a bit of L just right of centre.

Next up in complexity would be a centre section formed by mixing L and R and feeding it to a third amp (or bi-amp). I have been using a single low-bass channel ("mixed bass") for the last 50 years.

My interests for the moment are purely in addressing the question making a great way to re-create serious music at home if you had a "blank sheet of paper" and a few dozen panels.

Any thoughts appreciated.

Ben
*yes I know, ESLs don't like walls. But for the moment, I am talking about channels, not room placement or other down-the-road questions like that, except as relevant to the larger issues.

Hey there folks,

I have a strange problem with my Marantz PM57 that I just can't get my head around. It had shorted amplifier chips in the right channel, which had caused the fuse to blow. I replaced them, and fired it up with my dim bulb tester - the tester lit up bright (100w bulb) and didn't dull down, the power light on the front of the marantz lit up and then faded out. I quickly unplugged it and searched for another short - couldn't find it. So, I powered it up again to look for something hot, this time it powered straight up, the DBT lit up and then faded to nothing and the amp worked perfectly. I performed an idle current adjustment, and then had it playing music for 30 mins or so. Then, I switched it off and went out for lunch - came back and now it is turning on with the same symptoms as before, a bright solid light on the DBT and no power on the front. The main filter caps are reading 2.2v when it is like this, as are the main chips. The only thing getting hot is the 3 pin plug from the transformer into the board, which connects directly to the bridge (not shorted), then goes to the filter caps (not shorted, reading within range of capacitance) and then to the amplifier chips.

9/10 times i turn it on it goes like this, and 1/10 times it will start up normally.

What on earth is going on here? can anyone help?

Many thanks

I plan on comparing the datasheets for these two ICs but I believe that they are similar. Anyone has experience with either or both of them perhaps?

This amp plays audio but every time I adjust the gain it will cause the speaker to pull in and out.I bypass the That 2155 IC but problem still there.

Any suggestions?

With the VFET round 3 OS boards released, those of use who listened to Papa and grabbed Tokin SITs are starting to get a little excited. I for one ordered the VFET chassis and have started collecting parts for the FE boards.

One thing that I have thought of is would be nice to get some small rectangular sheets of Keratherm Red which we could cut down to mount the Tokin SITs. For those of US based Keratherm is had to track down. Do not think it would even need to be precut like the version you currently stock. Just a thought.

Hi looking for frd and zma files for SEAS H1571 mid woof, 27TAC/GB and T25CF002 tweeter. If you could point me to a database or provide them I would appreciate. Thank you.

My trusty "indestructible" meter decided to give up working last week. As it turns out, one of the original energizer batteries that was supplied from the factory which was still in date had started to leak. Apart from some fractured plastic from the swollen cell, there didn't seem to be any corrosion or ingress of any battery acid. The meter was bought in 2016 and the batteries dated ok until 2025.


Some missing plastic bits but otherwise clean. (I've got the bits which I can glue back in if needed)



What foxes me is why I now see this no matter what new batteries I put in it. Am I doing something wrong or has this killed the meter? Even dafter question is will Fluke warranty this given the battery that leaked was in there from the factory. (this was bought from an authorised supplier by me)

Hi guys.
I'm trying to repair a KRK VXT-4 near field studio monitor.
I have searched the internet for any schematic for this monitor for a long time but couldn't find anything.
The HF driver (LM3886) blew up and needs replacing. Now, the main amp pcb is covered with this nasty black silicone, and I had a hard time to get it off so I could see what's going on in there.
I am stuck in identifying the part number of Q1 on the amp board (or main pcb).
Maybe someone here cold help me with that.
Of course, the complete schematics would be excellent as well...

Hi,

I would like to know if the concept of the JBL Paragon diffusion board has ever been applied to fullrange speakers, and if so with any benefit.
https://en.wikipedia.org/wiki/JBL_Paragon

Thank you in advance

I have recently bought two Fostex FE103 Sigma for a pair of single driver loudspeakers.

I have found several possibilities in the net about using it in horns, TQWP, etc.
Did anybody of you made a PETITE (bass reflex) and can report about the results ?
I must admit that I am a bit hesitating making a more complex box when a simpler one is also working.

Klaus

Hi,
I'm looking for a pair of Seas A26RE4 to built A26 speakers. Living in France, I prefer in EU.
If you got some...

Damien

Hi all,
The signal led stays on on 1 ch I replaced the 3 tr that drive the led. checked all the resistors and caps. it is still on. When i short e to b on the first tr the led goes off the problen seems to be coming from the source located on the back input board. I checked everyhting there and replaced the input ic. I dont know what to else to check. anyone have any suggestions?
Thanks.

Unused ELMA switch

sowters are sold, the switch is still available

ELMA Switch 04-2133 2x 24 Positions(Stereo), make before break


50,00€ for the ELMA switch(100€ new)

Years ago, while living in the US, I built a CTH (Cavalli Tube Hybrid amp) - the 'original' (well, the BoM is from 2011) version. I ordered a power supply (24 VAC output, with a 120 V input) and this all worked beautifully. I then moved to the Netherlands and bought a new power supply (with 240 V in and variable out, including 24 VAC) that worked briefly, once, and then died. Rather than buy a new one - I have a spare power supply from a ceiling lamp that delivers 11.5 VAC with max 210 W. I opened it up and it has a normal-looking transformer with a double set of windings in parallel. I figured if I put these in series, I should get 23 VAC which might be just enough for the headphone amp. The power supply is an EagleRise EET210CK. Mine looks slightly different, with a N (neutral) and L (live) by the input.
What perplexed me is that when I measured the output voltage I measured exactly 0 V. After much headscratching I finally figured out the primary winding's two contacts are not N/L but rather, measured to ground, each has 120 V. The output, similarly, has a voltage on each side, so again no N/L. Each side has a set of secondary windings.
Question is: can I use a power supply like this for the CTH? What happens if I take the secondary windings, put them in series and connect them with the output? Do I now have a N/L, or do I end up with some bizarre construction with no true neutral side? If so, would that matter?

Happy to post pictures of the PCB of this thing.

(Yes, I know this is all dangerous and working with little knowledge makes it even more so. But I learn from these exercises.)

Assembled by Fab, the designer.

Mosfets 2SJ313/K2013
output Mosfets ALF16P16W/16N16W
Everything is matched.



£300 the pair + P&P. If I can find them I'll also throw in a new pair of 24v SMPS that can be used to testing.

Specifications of USSA-5 (obtained on 1 channel) (updated 2019-11-24)
 Gain: 20dB (or x10)
 Input sensitivity: 1.8 V-peak for output (20W rms)
 Damping Factor (100 Hz , 8 Ohms): [35 – 45]
 Output impedance: about 0.2 Ohm
 Input Impedance: 22K Ohms
 Max power into 8 Ohms before clipping: <25Wrms (at Supply voltage of +/-24Vdc, 1.2A Bias current)
 Power in Class A (8 Ohms): depending of bias current
 DC offset: trimmable to < 3mV
 Rise time (10 to 90%) < 1.3us

Hello there,

I'm totally new to SMPS design, this is my first attempt. The plan is to have a module with USB type C PD input that will power up DACs and preamps. There are 4 power supplies in this design.

Analogue PS consists of LT8582 as a boost converter and a inverting boost converter with LT3045-1 and LT3094 LDOs in VOIC mode (in the LT8582s' feedback loop).



Digital PS is two SEPIC converters delivering 5V (or any other low voltage). The LDO setup is the same.


I would greatly appreciate it if somebody could verify my design. Any tips and corrections are greatly appreciated!
Have a nice weekend

Hi, in Sakuma tube amps, there is a lot of examples of simples diodes + CLC or CRCRC (bigs C) CC filaments supply. Even in DHT tubes. Is this CC filament supply type a good performer?

HI ,

Mooly:hbeat:​

Hi, I have a 1970s British amplifier Ferrograph f307. I need help. Please help me. The voltage of the gold sealed tube thrust triode of this machine is 55v. What is the static voltage of the emitter R506? thank you,

Im looking for various Proteus Cross Over designs.
Here is my contribution. My first 3 way and a 2 way.
Any ideas to improve the design and inputs welcomed.

All service manuals I find are the versions V1.0 and V1.1.
Both versions uses the UPC2581V-S for IC601 (front-end for power amp unit) - go to
http://sportsbil.com/sony/STR/STR-D/STR-DE185_v1.0.pdf

I need the version with the STK350-030 on that place - go to
http://audiolabga.com/pdf/STK350-030.pdf
The outline and pin configuration is different, thus the location parts on the PCB.

On the main board (component side) I read follow letters:

SONY > PF-LP< MAIN (STK)

Maybe one of the members can send me the URL for download the wanted manual or at least the right version, for the STK equipping (maybe v1.2 or v2.0)

I did google for this. When a 2nd order crossover is used, tweeters are often wired out of phase to keep them in phase with the mid( or mid/woofer in 2 way spk). But in a 3 way system, where the tweeter is wired out of phase with the mids, I have not seen the woofer also wired out of phase.

Why is that?

Hi

I'd like to learn how to design a dsp crossover and am after some help on how to get set up and what to read. I've read around a lot and found a guide on desiging dsp crossovers on asr but don't know if its polite to refer to that here. I'm sure there are better resources here though

I tend to understand thinngs best with an iterative practical approach: read some theory, play around with it until I understand it. and then repeat ...

So I was thinking of building some speakers with well behaved drivers and use pc software,to get a functional but basic crossover built and then iteratively learn how to design a good crossover.

I know there are some big holes in that idea that have to be filled in, like

• what speakers
• what box
• what ampplifiers
• what interface between the computer and the amplifiers

so the questions I've looking for help on

Is this idea practical?
If so what sort of kit will I need? I'm looking for basic gear but want it to be able to get great sound.
What are good not too technical guides to read up on the theory.
What guides are there on setting up a basic crossover for a baseline to get me started.

I like listening to orchestra's, concert bands and choral music (eg Mahler) as well musical pop and rock (from abba, carpenters, simon and garfunkle to Pink Floyd and Queen). I was thinking of using one of Troels Graveson's designs as a basis for the speakers and box- maybe The Loudspeaker 3. I'll

My budget is going to be around $4000

thanks in advance for your help
Martin

Hello, I'm looking for a pair of Magnequest MQ565 Dynaco ST35 Output Transformers. Nickel Pinstripe or other versions. Thanks.

Hi All
I have been given a Summit Audio MPC100A , Reported fault is no output
On checking i can see that 3 watt 75R resistor is getting so hot its dropped out the board
There are 2 modules OP1- OP2, one or both are Bad, Can see that one is burnt up
I have no diagram and probably won't get one
I have contact summit audio, but don't expect a reply
Do you know where i can get replacement output modules
many thanks
JB

Inspired by circuitbasics.com article.

Latest revision of the LM3886 gainclone PCB:

• Power ground and signal ground are two separate plains with the ability to connect together.
• Plus and minus power supply plains are doubled on both sides of the PCB for the optimal current handling.
• .25 inch terminal connectors for power and speaker wires.
• Space for 5mm or 10mm lead input capacitor.
• Space for all of the optional stability components.
• Space for six supply bypass capacitors
• PCB size is 70mm x 45mm.
• Four holes for mounting PCB to the heatsink with 90 degrees bracket or to the chassis.

List of parts:

• C1 - 2.2uF - WIMA MKS2 film capacitor - Mouser part # 505-MKS2C042201KKSSD
• C2 - 220uF - Nichicon Audio Grade Electrolytic Capacitor - 647-UFG1V221MPM
• C3 - 680pF - WIMA FKP2 film capacitor - 505-FKP2680/100/5
• C4 - 220pF - WIMA FKP2 film capacitor - 505-FKP2220/100/5
• C5 - 10pF - TDK C0G Multilayer Ceramic Capacitor - 810-FG18C0G1H220JNT0
• C6, C11 - 1000uF 50V - Nichicon Electrolytic Capacitor - 647-UPS1H102MHD
• C7, C10 - 22uF 50V - Panasonic Organic Polymer Capacitor - 667-50SEK22M
• C8, C9 - 4.7uF 50V - TDK X5R Multilayer Ceramic Capacitor - 810-FG14X5R1H475KRT6
• C12 - 100uF 50V - Nichicon Electrolytic Capacitor - 647-UVZ1H101MPD1TD
• C13 - 0.1uF 50V - TDK X7R Multilayer Ceramic Capacitor - 810-FG18X7R1H104KNT0

R1 - R6 resistors are 0.25W.
R3, R4 - 0.1% tolerance - can be hand matched from like twenty resistors of 1% tolerance.

R7, R8 - 10 ohms:
2W Ohmite Wirewound Resistor - $1.33 - 588-WHC10RFET
3W Ohmite Wirewound Resistor - $0.79 - 588-53J10RE

Gerber files are attached. Great website to make those boards is JLCPCB.

Has anybody seen a list of russian rectifier tubes and/or diodes, or have any experiences of use, quality etc.?

Hello,

I came across this page on the internet:

http://www.baudline.com/erik/bass/xmaxer.html

Now I can enter all the values there and get the Xmax value I need to reach the required frequencies as an answer. So far so good, but only the diameter of the speaker driver is asked here and not the moving mass. I plan to make my driver relatively heavy and that should affect all of that as well. How exactly do I have to complete the calculations now? Or am I completely wrong and the mms plays no role here ?

I have been playing with ACA's recently, swapping between bridged mono and parallel mono operation... and then I realised that instead of having to do a fair bit to go from one configuration to another, there was a pretty capable rating-wise switch at the back that can do both in no time at all.

So, I took a few photos that explain what I did. The switch contacts should be used in parallel to half the contact resistance😉

I considered the safety as well... and could not see any problem in using the switch for either mode.

Especially useful if you want to try monoblock ACA in both modes at your friends' place, for example, where each mode may sound different depending on individual tastes, rest of the system, speakers, room size/damping...

Also, why settle for one mode, when you can change the mode to suit your mood... don't forget to re-wire speaker connections when changing the modes.

hi everyone, another hard fix to me.

rf t1000-1bd with no audio.

replaced lm5110 because low voltage at vvc and no output. replaced a lot of diodes and transistors near the pulse transformer with new ones. i have pulse at input and outputs of lm5110 and at gates of outputs mosfets. it is the carrier signal ok??

playing 60hz tone with no luck no changes at gate output mosfets.

pictures in order inb, ina, outb, outa last one is gate of positive side output mosfet.

Does anybody in here have the schematic for the Caliper Sign. X-over to share? Can´t find it anywhere. Just the Caliper. The Signature is totally different.

Looking for Usher tweeters (9950s) to mate with my 8948a drivers

looking for someone that may have used this tweet. There is a resonance at 30khz in the spec sheet. Do I need to put a notch filter on it or just ignore it as it is out of hearing range....
https://www.madisoundspeakerstore.c...tac/gb-h1825-aluminum/magnesium-dome-tweeter/

I recently started experimenting with this old driver I had sitting around. Despite what can be said about it, it seems intelligently designed for it's application.

This is not to make specious arguments about this being a Hi-Fi driver. I am just a bit surprised and interested in the engineering of this driver because it is good enough that, if I had such a TV when I was a child I know I would have had fond memories of it. The response seems to be perfect to equalize out when it is covered with cloth (a microfiber towel in this case). It's true there are 5.4k and 8.8k peaks, but they are outside the really bothersome range.

These measurements were taken with a small series inductor which improves the response a bit, but does not really change my point.

First image is raw response, second image is with cloth. 3rd image is the speaker crossed with a tweeter from one of my Dayton B652-Airs.

Just curios anyone have try this?
How the feel?
How many xmax?
Is this good for 8th bandpass?

I've come across several sources that indicate that there is a phase reversal with 2nd order (12db) crossovers.

I've seen several 2-way designs that recommend wiring the woofer backwards (connect positive of amp to negative of woofer). And in 3-way designs, that the midrange be wired backwards.

I'm wondering this this 'phase reversal' is a true inverting of the signal, or if we are dealing with some strange phase shift between voltage (signal) and current?

While I plan to try it, I'm wondering if I open my three way cabinets and send mid-band frequencies out of the amp (mid-bass, mid-mid, and mid-high), then compare the signal coming out of the amp with the signal coming out of each section of the crossover, will I literally see the XO signal inverted?

In short, is wiring the speaker backwards because of a true and literal inversion of the signal as it arrives at the speaker component, or are we talking about a shift between signal and current that require the speaker component to be wired backwards.

And more important, is this all a load of baloney, or is it a serious approach to internal speaker wiring?

Enquiring minds want to know.

Steve/BlueWizard

Hi Guys,
So, I've fully rebuilt this amplifier and am trying to set bias. I've seen other threads where I should check multiple emitter resistor cross voltages but, I get zero volts dc across all the .68 ohm resistor which is the (blue-grey-silver-gold) ones but across the 10 ohm (brown-black-black-gold) resistor the bias pot seems to be adjusting it no problem. I'm not sure if this is normal or if something is wrong. The heat sinks are also cold about 40 mins on. Attached is an image and schematic for reference. Any suggestions? Thank You.

Ben

Just received some new parts as follows. I have 2 of each (for monoblocks) and thus am able to swap to see if a specific part is the issue.


The filament transformer (4V for an Aa tube) + 2A LC filament supply works as designed. spot on. no problems.

However, filament transformer (20V for GM 70 tube) + 3A LC filament supply produces a significant mechanical hum/vibration from the filament transformer. The GM70 tube is drawing 2.88A current (spec is 3A). The GM70 is measuring 19Vdc (spec is 19-20Vdc). So, I swapped transformers. Still same issue. I swapped LC filament supply. Still same issue. I swapped tubes. Same issue.

Then, instead of using the 3A LC, I tried a Coleman V9 regulator. This worked fine. Just a slight mechanical hum from the filament transformers, but nothing worth discussing. So, it appears that the LC is causing the filament transformer to hum, yet the transformer is rated for 3A. Any thoughts on this?

Here is the LC design:


FYI: Once I get the filament transformer mechanical hum problem fixed, I will be adding another choke. This will give a nicely supplied LCL. I am comparing the LCL to the LC + Coleman solution. Should be fun once the mechanical hum is fixed.

For sale are two LCD screen modules, 6€ each, or 10€ both, plus shipping.
These are 16x2 characters big. One is white characters on black background, the other is black on white/green.

Please see pictures below.

SOLD the white on black display.
6€ for the other one still available, plus shipping.

I have extras to sell of the Electrodyne/Quad Eight ACN 3B's. Tested and working. Vintage summing modules, 21 input combined into one balanced output. Input can be either 600 ohm or 10k unbalanced.

Hi I am looking for a well built pass pearl ii. Thank you
Located in USA

Hey guys, I am trying to upgrade my transformers and came across NP Acoustics as a potential choice. Corresponding with them has been great and the gentleman running the company is very prompt with his responses.

I need 1 pair of OPTs for my GM70 monoblocks, 1 pair of interstage transformers for 2A3 tube driving the GM70 and 1 Pair of ITs for 4p1L preamp (the IT gets used as an OPT there).

I am good in having finalised the specifications of all 3 pairs of these transformers. However, what concerns me now are the hundreds of user impressions about the amorphous cores sounding bright, brittle, sharp in trebles and light on bass. I really can't do with this sort of sound/tone. What is paramount for me is to get a detailed yet sweet tone and not utterly bright and unnatural sound, if that makes any sense.

I understand NP Acoustics has few great feedbacks recorded online and since they perhaps use large core sizes, hence folks may not have observed any loss of bass. However, I wanted to open this thread so that those of you who have experience using these transformers could let me know if this company and moreover amorphous core trafos will indeed be the right choice considering my tastes as mentioned above. Does it make sense to only go for the ITs as amorphous and the OPT as something else?

Thanks in advance

Kartick

Attempting a Quad 606 clone using Chinese PCBs as shown. Working well on headphone (390R resistor in series with load) but massive distortion on speaker - which increases as heat sink area increased.

Hi all. Total REW noob here. I'm planning on running REW on a Windows 10 laptop initially. Is there a particular mic, stand, other parts, etc... you would recommend starting off with? Would I be better off with the UMIK-1 or -2 or something completely different? Any particular mic stand that would be good to start with? Any special tools needed other than a laptop, software, mic, mic stand, etc.. to get started? I'm assuming most just order from miniDSP directly?

I'll be starting out doing some room tuning but want to eventually build a high-end set of mains for 2 channel listening w/ multiple subs (true 3 or 4 way active setup). I'll also be playing around with my current HT setup to experiment with multiple subs. For reference, I'm currently running a 5.2 setup with active subs using a Denon AVR-X4400H w/ 11ch pre out capability. I have a separate Adcom GFA-555 I've been using on my mains but will probably DIY separate amps when going for the active mains build.

I don't currently have any miniDSP hardware. I wanted to get the room measured and treated as my first step, but does it make more sense to buy a hardware and mic bundle if I'm planning to go down that path?

Sorry for all the questions, but there are a lot of options on the miniDSP website. I figure some of you have already been down this path before. Any recommendations about a good starting point would be appreciated.

Thanks,
Bill

Good day guys, have an Hifonics amplifier that goes into limited protect (momentarily mute) when playing a deeper note and more often when it’s powering two speakers, I’ve already replace rail caps and even the output filter cap which was swollen.
The customer described to me that the relay disengage when it’s momentarily in protection, I don’t know if the PWM power supply card wants recap if it’s a case where the relay is opening due to low voltage/current to feeding it, and also if there’s any applicable mod to let it play lower Ohms without muting (as like some of the JBL BP series amp).

Hi there, I bought an old transformer to built a guitar amplifier for personal use. When it arrived I took a no load test to see if it was working. The voltages on the HT reads 450v -0 -450v. The transformer is very heavy as it came out of a 100w amp running 4 x EL34s. My idea was to use it on a 50w build but I dont want to use it with that high voltages as I am planning to use solid state rectifiers. That would bring me into the 630 range and feel that is going to load the tubes too much. The circuit I have in mind is a Hiwatt clone. Would voltage dropping resistors work to bring the voltage down to a reasonable 450v dc or should I look at another transformer. Where should I put them? before or after the rectifier. Any help would be great Thanx.

Hello DIY folks.

As we all know, acoustic measurements can be extremely beneficial in designing loudspeakers. As far as budget hardware is concerned, the miniDSP Umik-1 is a very popular solution.

The Umik-1 comes with SPL & frequency calibration. However, it doesn't fulfill any standards, and since there is also no public review in which its performance / accuracy has ever been tested, it basically has been up to guesswork if this piece of hardware provides reliable data.

To try to bring some light into the darkness, here's my comparison vs. reference (IEC 61672 Class 1) measurement hardware:

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Regards
Stoneeh

I'm trying to measure the phase and amplitude of four 1KHz audio pulses from four separate
QSD's. The 1khz tone upstream is from one source. I'm told that the output Z of these is low enough to use balanced mic inputs in a audio a to d, (~300 ohm input should be fine). I'm looking intially at a cheap 4 channel interfaces like a MOTU M4 4x4, (115db dynamic range, 60db gain). I don't know if this would do the job. Two things I need in hardware as well as software. I need to have phase correct sine display and if possible to resolve 1uV. So I'm looking for software that can give me in phase the fours sources. I'm also told the 115db dynamic range should be good at least for the start. So I'm looking for thoughts on hardware and software recomendations.
Thank you for checking out, Michael

I was thinking about building a relatively cheap portable system using an SMSL SA1000 amp (50w). The reason why I was thinking of using this amp is because I don't need a 80W-100W+ amp and it has Bluetooth 5.0. I wanted to keep the power requirements as minimum as I could while still providing some decent level of power. The only issue is I am still having a tough time finding a batter pack/bank that isn't $250-400 to power it. The SMSL SA100's power supply is listed at 19V 6.73A.

The speakers i'm driving are Dayton Audio B652 6-1/2"
6 ohm
Sensitivity: 87 dB 1W/1m
40 watts RMS/75 watts max

Would anyone know of a way to power the SMSL for under $200? (wanted to keep this system fairly cheap)

Hello everyone, I'm new here, so I hope you will be forgiving of any initial Pecaillo's.

I just got back from the 2015 California Audio Show in San Francisco. That in itself isn't that interesting for DIY'ers, but I discovered that Mundorf is now selling a speaker kit. It comes with a completely Mundorf parts crossover, Mundorf AMT tweeter and Accuton mid-woofer. According to Mr. Mundorf, they needed to be around 40 cm from the back walls, but I'm not sure if that is needed with a sub.

Sadly, the room or the electronics really sucked and I did not hear much I liked there.

I'm wondering if anyone else has experience with the Mundorf AMT tweeters in general? What I am looking for most of all is an endless decay. I'm not sure if this is ever a tweeter's job, but systems that I most like tend to have the ability to show an instrument's or a voice's decay seem limitless. In most systems I hear there's a point where it just gets cut off. This is by comparison, so for all I know there's just a post-signal rigning, but I like it.

This is the main reason I chose an ARC DAC-8 over others in it's price range and above. The end of a plucked string, or the decay in Emilou Harris's voice just seemed to trail off forever. Otherwise, it's like you reach a diode, and bam, off. Sorry for the bad descriptions.

The second thing I need is it has to maintain clarity in a small space. I have Focal's now, but going to a San Francisco apartment I've lost a lot of the clarity they had in my previous apartment, so I think what I want is something with relatively narrow dispersion.

I've also been thinking about a kit from Selah audio, the Verity.

Thanks for your thoughts in advance!

Erik

Hi Everyone,

I haven't been here in a while but a recent built by Troels Gravesen has made me think about building a new, 3-way active center. Mostly I'm intrigued by the Illuminator 12MU he used.

Here's my question. Assuming I go fully active with a similar design, is there any benefit to digitally delaying the tweeter or tweeter/mid to co-locate the acoustic plane for all 3 sets of drivers?? In simulations I've tried before using 2-way speakers it seemed the only real benefit was smoother off-axis response. Assuming I went with a 3-way active amp/crossover is it going to be worthwhile to attempt to simulate this using digital delays?

Thank you!

Erik

hi guys

any of you know if this is a cap? (red arrow) and if so what type ?

its my mates and he says it has a bit of a hum. I thought transformer hum, but he seems to think it is this component

cheers 👍

In Jean Hiragas Book "LED AUDIO Initiation aux amplis a tubes".
Page 98. Output transformers for push pull amps.
Freq. range. I think that freq. range for Tango, Lux and Tamura is measured at 1 W output, and for Millerioux at full output !
Does anybody know the core size for some of the 28 output transformers ?

Going where few (in this forum) had dare go before.
Pick your favorite diode, which one 'sounds' best?😉

Hello,
I brought 2 used PA cabs Sr-4733x for cheap would like to build 2 ways x-over. The CD is not original. The woofer is from JBL don't know if it's original . I don't trust my measurements as it doesn't sound dull i.e. missing the high . I did the individual drivers in DAT. I eventually will try to get the accurate measurements in REW.

Hi guys - selling a large quantity of my valves. Prices can be negotiated to some extent for multiple numbers. Please contact me with any questions or if you want more details about particular valves.

I would draw your attention to the European radio triodes - these are rare and collectible and have a gain (mu) of 30 or over. They sound very good and make excellent driver tubes for amplifiers.

Hi,

Thank you for reading my question.

I'm interested in upgrading/modding the amp in an old Yamaha receiver and wondering if it is feasible to do it with one of Pass designs that are available in the store.

I am a newcomer to working with electronics and don't know enough yet to be able to think my way through the project.

The heat sink is approximately 8cm by 16cm. It is 20 watts per channel into 8 ohm

I've attached 4 pictures of the inside of the case.

The model is a Yamaha CR-240.

I tried to paste a link to the hifiengine info page, but the forum would not allow me to post a website link.

Any advice would be appreciated.

Thanks in advance.

Hello,

Does it make sense to build a woofer in such a way that it has a relatively high mms in order to get a very low frequency response? Especially when you build a multway system and the woofer is only responsible for the really low frequencies. or would you advise me against it?

As new Ortofon AS212S tonearm with box €.1050

I have a problem that I have not solved successfully after many hours of staring at the German manual (PE 3046) of my Turntable (I don't understand German and use Google translate for pieces of it), and the English manual of the similar Dual 1224/1225 turntables.

So there is a black lever underneath the platter that is actuated by a cam that both raises and lowers the tonearm, and pushes it off of the tonearm rest onto the record and returns it from the record to the tonearm rest. I got a new rubber steuerpimpel for it, and it is working much better, but not perfectly. The steuerpimpel (a little rubber button) is placed over a steel pin which the black lever presses on to move the tonearm inwards towards the center of the record and outwards towards the tonearm rest.

When the record ends, it seems to work fine, with the tonearm being lifted and pulled outwards and placed on the tonearm rest by the black lever mechanism being actuated by the cam. However, when I start a record, a thing happens that I can not figure out. The tonearm is lifted and moved towards the center of the record. However, it is always moved back off the record before it is lowered down and so misses the record. From watching videos on Youtube, it's not supposed to pull the tonearm backwards towards the rest when starting a record, it's only supposed to go outwards and then drop onto the edge of the record.

There's an eccentric nut that one can adjust by switching the speed lever from the 33 to 45 rpm position, which adjusts the position of the tonearm before it is dropped onto the record. This works, and it changes the position that the tonearm is moved inwards to, but it is always moved outwards again and drops the tonearm off the edge of the record.

I also played with the anti-skating control to make sure it wasn't being pulled too strongly outwards. Even at the zero anti-staking control position, it still moves the tonearm outwards after moving it inwards.

Anyways if anyone has encountered a similar problem on Dual or PE turntables that would be helpful. It does play beautifully if I set the tonearm on the edge of the record manually. Thanks!

Dan