Just in case somebody here has already done the hard work.
Would anybody have the values for the cored inductors in this old RadioShack 3-Way crossover?
I am assuming they are book values for 8R drivers but just in case they are not.

I an trying to insert a 100mm midrange into a big 2-Way and wondering if I can utilise this old unit and not go out and order more parts

I have a pair of FOCAL drivers (7L-011DB) but thinking about using them in a DYI build.
Would these work for a full range set up? Or open baffle? Or both.
Obviously, I'm a clueless newbee...

Anyway, they are the metal basket Focals, not the later plastic baskets.
They seem in excellent operation condition.
Got them in a DIY set I bought years ago and they've been in the closet since then.

After some several test and adjustment for how many months to make this Diy amp i will share to all diyers with the permission and support of apexaudio
Who ever want to make the amp or edit/modify the layout is free to do what ever he/she want...
I will only share what i learn on this diy amp,,(I'm not a PRO)
There is no Schematic i only use or base on original schematic of cr@@t and vertex shared by apex


Some changes was made during test
test voltage only at 60/120 -/+
i only use 2sc5200/2sa1943 for test
Amp i made only 2 stepper
final power transistor should be mjl4281/4302 or mjl21195/21196 Or 2sc4029/2sa1553
2 mje15034 replace mje13007
2 mje15035 replace mje5851 or 5852
mje transistor should be mounted on main heat sink,, i don't have the time to reedit the pcb,,(Looking forward to the new Project)
zobel network from 103/250v/4.7r replace 473/250v/ 4.7r 5w
BC550/560 replace 2n3906/3904
Dc servo ic Is LF411

added balance -/+ input with sensitivity switch

link of schematic used:
Download crest.rar from Sendspace.com - send big files the easy way

Hello,

i have a preowned AI 3 convertetd with a M3A board and John Curl Boards. I like this Amps and the MC pre sound delicious. I bought it 1.5 years ago with a quad set of
6H23p tubes. As they become "hissy" (sounds like the wind blows through your speaker), i have changed them to a new quad EH6922 (gain switch is low).
After 25 hours of listening in 3 months I got the hissy stormy sound again in the left speaker. I unscrewed the topplate, the sound was good for 30 minutes, than the hiss (or like waves - volume is changing) on the left speaker was back.

Questions:
- If the tube will get burned out by the AI...will the hiss be permanent?
- 6922 EH not so stable as 6H23p?
- What is better for the tubes - switch to high or low gain?
- Should i replace the electrolytic caps?
- Is there a way to change the filament or anything to stop valve eating? (I read it in another thread but I would need a part list an exact guided way what to change from somebody who had done it)

Thanks for feedback.
Marcus

Turning a 1940’s era tube radio console into a modern boom box with an active subwoofer as a gift. Fullrange drivers above will have their own enclosure inside/no open baffle like the original. Which of these three would you choose? I’m leaning towards the high sensitivity of the Faital since we’re not talking a lot of available amp power here……30w each left and right with 60 for the sub. The L and R are also actively high passed by the amp at 100hz 6db. We’re talking mostly bluetooth audio here so please consider the baseline input signal degradation……..just quality room filling sound that will last and endure some volume. Thanks for reading.

I had to move my setup and now it sounds pretty bad. One speaker is shoved in the corner, the other speaker is in the center of a wall with the opening for a staircase right behind it. My listening position is right against the back wall. I'm currently using full range markaudio a10p drivers in pencils, they sounded great when I had the room arranged differently, but now the two speakers sound lopsided and there is little to no imaging. Are there any speaker designs that would be less affected by the weird placement?

Hello,

I am novice in building DIY speakers and started trying to build a DIY 3way speakers with following drivers.

• Woofer: McCauley Sound 15" Woofer B1560 - 350W RMS, 35 Hz to 1.2 kHz at 8 ohm
• Mid-Range: Faital Pro 6FE200 - 260W RMS, 85 Hz to 6 kHz at 8ohm at 95dB
• Tweeter: JBL Super Tweeter Selenium ST200 - 70W RMS, 2 kHz to 20 kHz at 8 ohm at 105db

I entered values into Crossover calculator and got this outcome.

Can anyone help me if I entered the correct value and is the ideal crossover value on caps, inductors and resistors?

I guess that the ideal way is to get a measuring microphone and measure the actual impedance and build a crossover but I do not have measuring microphone at this stage so would like to go with driver specs if possible.

Any feedback would be hugely appreciated.

Thank you.

Hello

which are better

NJW0281G / NJW0302G

or

2SC3263 / 2SA1294

?

thanx

Hi All,
My friend Mauro (mauro2098) and I, after Jim's mods on PSU, decided, inspired by Ken's superb work, to follow his path.

We started buying a cheap SL1200 top plate chassis:



Next step, filling the holes and make all borders square with alu-like epoxy plaster:





And finishing with epoxy car plaster:









Mauro has done a very nice work 🙂

Time to choose the veneer:



Mahogany, walnut or ash burl?

In my search for Altec 288, I encounter Altec 291-16A in great condition and I bough them, knowing that theses drivers are the same as the 288C minus the diaphragm (Symbiotik) and that these drivers in good condition are rare and pricey. You can found slignthy different spec sheet on the driver : earlier and later.

To my knowledge, no frequency response or other objective data was published on the net. Opinion are scarce and the few I found said it doesn't go as high as the 288C, but its midrange are smoother. Anyway I planned using either a JBL 2405 or EV T350 (or both) on top. Do you have any experience with this driver (horn coupling, amplifier used (in passive or active crossover configuration), crossover frequencies, blend with woofer and tweeter, etc.) ?

Valve amplifier 10 watt. Uses PSU transformers but sounds fine.
12AX7 front end and pair EL84 push pull drivers.
Yes, I messed up with too small a transformer and bigger one is glued to pcb.
Open to offers. £15 postage and packing. UK only.

I'm looking to supplement the higher frequencies of my existing speakers (Leak Sandwich 15 ohm) by seating a tweeter on top of the speaker, similar to what is offered by off the shelf super tweeters.

The plan is to buy (for each speaker) a tweeter (Dayton Audio PT2C-8), a variable L-pad so I can play with the SPL, and capacitors ranging between 2 and 5 ohms to try different first order high pass filter points. Clearly this isn't very scientific - as you may have guessed from this assortment of parts, I haven't done any measurements to get an idea of where I'd want it to crossover or how loud. Furthermore I don't really know what to do about lobing issues at this point - lobing issues seem kind of messy, so I think I'll just try different tweeter placements until I find one that sounds "less lumpy" - perhaps even rear firing.

My question is, should I be low passing the existing tweeter in the Leak Sandwich, so as to help mitigate lobing issues? This seems like the sensible thing to do, but then I wonder what users of super tweeters do? My understanding is that they just plop the super tweeter on top of their speaker without any further modification to the existing crossover network. Do they just 'put up' with the peaks and dips?

Hi folks!

I have an AKAI AM-U310 and after many years of music I lost the sound unfortunately.
Here is the story. I took an output for a mobile phone and I fed it into the AUX input.
Some seconds later the amp stopped.
What I have now. When I power up the amp I didn't here the click from the relay to operate.
After some research in this forum ( Amplifier Akai am-u33, powers on, but no sound ) I took some measurements to find out the cause of this fault.

All the AC measurements on the transformer was good the same as well with the DC on the bridge.

Then i have checked the fuse resistors FR1,FR2,FR3a,FR3b,FR4,FR5 out of the circuit and I found them ok.

Later i have checked the transistors TR1a,TR1b,TR2,TR3,TR5,TR6,TR7,TR8 and TR9 out of the circuit and I found them also good.

The final step was to take measurement on board with power on which I will demonstrate them below.

TR1a / TR1b
schem - measurements
B 0 - 0/-47.3V
C 14.4V - 0.3/0.4V
E 0 - 0/-47.3V

TR1b is bizarre.

TR2 and TR3 was ok

TR4 / TR5 TR4 / TR5
schem measurements
E n/a / n/a 0.01/0V
C n/a / 0.1 0/46V
B 14.3 / n/a -0.07/-0.9V

TR4 and TR5 have bizarre output.

TR6 / TR7 TR6 / TR7
schem measurements
E n/a / n/a n/a / n/a
C -0.6 / 0 -0.7/0V
B 9.6 / -0.6 9.1/-0.7V

TR8/ TR9 TR8 / TR9
schem measurements
E 21 / -20.9 20.9/ -21
C 26.6 / -21.6 21.6/-21.7V
B 40.9 / -43.1 43.1/-44.3V



And last but not least all the ICs

IC1 in equalizer board was great.


IC2 STK 3042

Pin / Scem in volts / measurement


1 / 0 / 0.1
2 / 0 / -1
3 / - / 43.5
4 / - / 44.1
5 / -1.1 / -44.7
6 / 1.2 / 44.5
7 / -43.3 / -43.5
8 / - / 0
9 / 43.3 / 43.6
10 / 1.2 / 1.2
11 / -1.1 / -1.2
12 / - / 43.1
13 / - / 43
14 / 0 / 0
15 / 0 / 0



So from pin 2 to 7 I have wrong measurements

IC3 STK 2250 SL


Pin / Scem - volts / measurement


1 / 1.2 / 1.2
2 / 45.5 / 43
3 / 0 / 0
4 / 0 / 0
5 / 0 / 0
6 / 45.5 / -43.4
7 / -1.1 / -1.2
8 / - / 0
9 / - / 0
10 / -1.1 / -43.5
11 / -45.5 / -43.7
12 / 0 / -43
13 / 0 / -43
14 / 0 / -43
15 / 0 / 43.5
16 / 1.2 / 43.5

Looks like that the half side doesn’t work properly.


IC4 LA6458S (edited 24/2/2020)

Pin / Scem - volts / measurement


1 / / 14.8
2 / -0.7 / -1
3 / 0 / 0
4 / 0 / 0
5 / -14.9 / -14.9
6 / / -7.8
7 / / 0
8 / / -13.3
9 / 15.2 / 14.8

Also here pins from 3 to 7 which are mirror one to each other have some not good measurements.


So looks like the problem passes from IC2 to the whole circuit and maybe TR 8 and 9 facing some difficulties because as I saw the have the ability to work with a switching time circuit 2SD612 pdf, 2SD612 description, 2SD612 datasheets, 2SD612 view ::: ALLDATASHEET :::



Also R36,37,38,39 were ok...



Can any one give me guidance how to proceed?

Would there be any benefit using a (mid)bass horn in a car? I have read that LF horns do not make any sense in a car since the car is a pressure chamber. I still believe there will be some gain left from the horn - but maybe the usable frequency is too high to do anything to the bass. The idea is to have a bass horn with a higher cut off that would be filled in by the cabin gain. Does that make any sense? I have some Peavey FH1 clones that fit my trunk - I wonder if it was worthwhile to pull one out, put it into the car and measure with open and closed trunk to see the difference in FR at the front seat. In a sense, the car walls would be a continuation of the horn, or am I wrong? It would be like sitting inside a horn. I am getting enough bass from the door speakers in my current car, so it is more like a theoretical question. I would maybe like to get a bit of the midbass horn "kick" in the car if that was possible.

Details here:
https://www.mattmillman.com/nicam-ii-bbc-engineering-opens-the-archives-shows-us-some-vintage-kit/

I've recently completed the TU-8200R Kit.
I've tried it with two pairs of speakers:
Axiom M3Ti (92 dB sensitivity, circa 2002) and Athena LS100B (87 dB sensitivity) circa 2007 - $50 each from Audio Advisor).

To me, the Athenas have been more enjoyable. Even with a smaller woofer, there seems to be more balance and low end. Both have decent soundstage, but the Axioms to me seem more bright, but not in a pleasant way. My listening habits range from Indie/noise rock to Blue Note Jazz to 20th century classical.

Naturally, I'm looking at new speakers (around $500) and have focused on these:

Klipsch RP-600M
Amazon.com: Klipsch RP-600M Bookshelf Speakers (Pair) (Ebony): Home Audio & Theater

Klipsch RP-5000f - I don't have stands, would be nice to not need them.
Amazon.com: Klipsch RP-5000F Floorstanding Speakers (Walnut): Home Audio & Theater

KEF Q150
Amazon.com: KEF Q150 Bookshelf Speakers (Pair, Walnut): Home Audio & Theater

Any experience or advice?

Over on diyma I crunched the numbers to figure out which drivers move the most air for the least money:

Bass Race 2013 - DIYMA Car Audio Forum



Based on that data, I believe the Alpine Type S 15" woofer is currently the 'value leader.' I base this statement on the following:

1) Making bass is all about moving air
2) The SWS-15D2 can move over a liter of air, and can be delivered to your door for $129
3) To put that in perspective, a prosound driver like the 18Sound 18NLW9600 can move 50% more air, but costs more than five times as much

There are likely a handful of woofers that can move more air for less money, but the ones that can don't have a flat BL curve. (For instance, you can almost buy *three* Pyle PPA15s for the cost of ONE Alpine, but the Alpine has more than twice the displacement, and a more advanced motor too.)

[/font]

Improved Ncore technology. New module NCx 500 OEM and a ney DIY product from hypex.

https://audioxpress.com/news/hypex-announces-new-and-improved-ncorex-class-d-amplifier-technology

and can check which chip is used as a SMD discrete volume control ? It is located beneath the main preamp board.
TIA , L

I did a bit of search and wonder why there is not a lot to find regarding this tube, especially given that the Curves / data looks really nice, even usable with an IT and in the Psvane version expensive, but still somewhat affordable: Psvane WE101D-L vacuum tube Western Electric Replica Pair [Psvane WE101D-L] - $453.99 USD

It could be an alternative to the 10y/801 in this application, no ? And when I remember the clio with Sif BA (which look a bit like smaller brothers), he claimed to get a unique holografic presentation as DHTrob with the 101D described as well...

...I am ready to pull the trigger, but just though if anyone has some listening experience and can compare to other types ?

In mint condition and perfect working order.
This has the upgraded broadcast modules fitted .

£520 + p&p or collection.

And nothing fell off so far. Think I'm good for a few more miles yet.
My engineering skills are now directed to cutting & piling of fire wood.
The Canadian Dream, Hewers of Wood & Drawers of Water. 👍

Cheers to All, John L Stewart, Brute Force Engineer😀

I have several old school Orion XTR and HCCA amps I'd love to repair and get back into my car ASAP but I'm new to amp repair and the shipping charges alone prevent me sending them to a shop. And pardon my errors if I use the wrong terminolgy (FETs, filter caps, etc) as I'm still learning. Amps in need:
Orion 450 XTR (smaller cap blew and shorted nearby FETs)
Orion 425 HCCA (powers on but no sound)
Orion 425 HCCA (blown one of two 30A fuses on power up)
Orion 2100 HCCA (magic smoke released on power up with tweeters connected, opened to find internal fuses bypassed! and FWIW my external 120A fuse did not blow)
Orion 2250 SX (currently working but needs a refresh)

I have some mild soldering, rework, and DMM experience and want to take on this project but I've run into a few roadblocks.

1) What kind of material is used between the heatsinks and the top of the power transistors? Its white and likely has adhesive on one, if not both, sides. I can provide photos if needed. I assume it is some kind of heat transfer tape, stuck onto the heatsink then basically thermally attached to the FETs after clamping and "cooking" for awhile. Obviously it needs to transfer heat and not be electrically conductive. I thought I saw Kapton tape recommended but I only see that available in transparent orange. I'm looking for the opaque white stuff that Orion used. Or solid recommendations on what else I could use. A link would be helpful!

2) On the opposite side of the FETs between them and the clamp bars there is another type of tape? Almost seems like double-sided foam tape. Any idea? I'd hate to get the wrong replacement stuff and have it catch fire from the heat.

3) Capacitors!!! I've spent countless nights looking for the right replacement caps but am confused. One example: XTR450 stopped working and I found a smaller blown cap that shorted a channel of FETs and also saw 2 larger swollen (filter?) caps. The larger caps are Samwha 3300uf, 35WV, 105C and the physical area used by the cap measured to about 1.050" tall and 1.020" wide. Ok, so I can filter based on those specs on DigiKey or wherever but I'm unclear on what else to look for. I don't see a "low ESR" filter and don't see much with a ripple over 3A (as I've seen recommended on forums). Can anyone provide a link for a good substitute or suggestion for what to look for in an acceptable cap? I'll probably need many of these larger caps so I want to KNOW that I'm buying the proper type/brand/series before moving forward. I don't see any Samwha 3300uf on DigiKey at all so substitutes seem required. And the fact that Digikey doesn't have these original caps listed is making it difficult for me to compare them to modern substitutes. Any advice or suggestions for a good replacement? And these Orion boards use radial can capacitors and not "snap in" style, right? I'm waiting for a rework station to arrive and haven't pulled anything off the boards yet.

Many thanks for any advice. Hopefully after I have the caps and heat transfer solutions in place I'll be able to move forward with this project. I've already pulled the clamp bars and started testing the FETs. Replacements/substitutes for those have been easy enough to find but the caps and tape have me stumped! Sad there aren't schematics available or even part listings. I've started compiling a list on parts used for each of the amps I've got and will share once completed. Hopefully it helps save others some time.

I started here several threads on which I was selling some transistors, so I decided to make one thread where I would say all about transistors what I am selling now…
So, during all those years, I have bought lot of genuine transistors for doing restorations on vintage audio, but today I really don’t have so much time to do this job, so I decided to sell some of my transistors collection…. As you probably knows, I already sold all genuine Toshiba MOS FET 2SK405 2SJ115, so I don’t have them any more…

What is your favorite smaller size 1" compression driver?

I need a great sounding driver (preferably under 75mm / 3" dia) to pair with a 6" mid, crossing above 3k. HF extension is important.

Some drivers that stand out -

• B&C DE7 (yes, it has a 3/4" throat)
• Lavoce DN10.142 (only 60mm diameter and goes pretty low)
• Lavoce DF10.142LK (a little too big but sounds good enougn to make it work)
• Selenium ST200 (a super tweeter, but it can cross fairly low)

Any other drivers fitting my criteria that I'm missing?

In my storage exist a couple of hand made bins twin 18" intented for sub woofer use
i can provide dimensions and or other data pics also
Then the problem is that i also have 4 brand new woofers that i know zilts about ...no data absolutely nothing
Question is how can i get the max out of this combo ?
the woofers i have come from a well known manufacturer in china that produces most of the time indeed value for money things
still since the woofer is an old model it appears that is not possible to finde enay datasheet
So the woofer is made from Soundking ....you may also find it somewhere as AUDIOMASTER or Metro Audio
Woofer is FA1841 G
As about the bin what troubles me is that it seems that both woofers share the same place and have a common port in the front

How can get the maxout of those ?

Does anyone have any experience dealing with this company?

I purchased a transformer from them 3 months ago and apart from one word answers I currently only have a tracking number that Poste italiane say is "not found".
The communication was swift and helpful up until I paid the money. Since then it has been at best erratic.

I hope there are positive experiences from others and if not then others are warned of this, in my experience, problem vendor.
Cheers
Gn

Hey folks. In a recent found of buying junk off eBay I came across this (which has a TDA1541A) in it:

https://www.mattmillman.com/remembering-nicam-part-3-philips-pm5688-test-receiver-teardown/

Just sharing if anyone is interested!

Hi

I finally got my test cabs up and running yesterday with some help from a more experienced speaker builder friend. They consist of scanspeak D3004/66000 tweeter, 15W4531G00 & 2 x 18w8531G00 per side.
The tweeter to 15w x-over is a passive design from Goran's (audioexcite) Revelation2 design and the 18W to 15W will be active (currently using basic DSP to get and idea of what sounds best first).
As expected for a first time listen, there were good and bad things that struck me. One of the good things is that they played nice and low and had a good sense of scale. What left me feeling somewhat underwhelmed however, was some of the dynamics from the bass. The 18W's are running in 40L each and have ports that are tuned to 33HZ. I played around with the x-over point between 140 to 650hz and found that they sounded happiest when crossed between 200 to 250hz. At the moment I have only used LR4 for this x-over. I should also mention that I don't think that the rear panel (screwed on) is completely sealed. In fact I'm fairly certain of this.
I noticed that when playing familiar music like dark side of the moon, deep bass (synths etc) rumbled through nicely and the higher bass coming from the 15w was good (including dynamics) but the thump from kicks drums etc sounded muted and a bit lifeless.
I am basically trying to get an idea of what the likely cause is and thought I would canvas the opinions of some of the people here? Do you think it is:
a) badly sealed cabs?
b) x-over type?
c) port tuning
d) something else?
Like I say, it's in the very early stages, but I would like some insight into this to help get things moving in the right direction. If I can get this sorted, I think they will make the basis of a very impressive pair of speakers (by my standards anyway😉)

Thanks

Paul

Hi folks, I recently acquired vintage Infinity 61 MkII with bass drivers in need for refoaming, but when I got home I noticed that tweeters are blown too. I opened them up and saw right away that connecting wires were broken. I managed to connect them and that's when the puzzle started.

First off, I measured resistance that seemed too low (0.4ohm) for a tweeter that is supposed to have 8ohm impedance and 5.5ohm dc resistance:

https://www.toutlehautparleur.com/tweeter-a-dome-audax-tw010i1-8-ohm-bobine-10-mm-facade-74-mm.html

I inserted it in the box and barely noticed the difference - it was playing very low volume. I replaced it with similar sized seas prestige and the highs volume immediately became normal. I repeated the same process with second one, exactly the same behaviour.

Could it be that coil is shorted inside, on both of them, at exact same point?

I'm thinking about one more series of LM4780 boards. If there will be enough interested members - we can make them in a good price (about 10$ for gold plated PCB). What do you think?

My LM4780 PCB can work in standard, stereo (2x60W) or parallel (1x120W) configuration. There is a place for MUTE circuit, diodes, and additional 10mm reaster snap-in 'big caps'.

I also have about 20 LM4780 chips from my last order. Universal preamplifier module can be also available:
http://www.audio.webd.pl/projects/riaa_pre.html

documentation

Hello,

here I offer transformer PhaseDots with no scope or signal generator pcbs from Marc Johnson.
(A little tester to determine transformer PhaseDots with no scope or signal generator)

ALL PCB SOLD!​

Shipping in padded envelope (not insured, not tracking) to

• Germany (without islands): 2,50€
• Shipping in EU: 4,50€
• UK: 10€ as small parcel (because Brexit & new custom laws, not insured, not tracking)
• other countries please ask

Hey, I thought it might be time to have a dedicated builders thread


Any builders around ?

as above. Can you please share? thanks in advance.

PS. I've seen some non-inverting PCBs in aliexpress and it seems to me that it's possible (relatively easy) to turn these into inverting?

Hello,
I notice some audio equipment has the PCB crimp pins shown in the photo, but I can't seem to find them anywhere.

Does anybody know where to source them?

Or alternatively, does anybody have a better solution to terminate wires directly to a PCB?

Thanks

Hi there, i'm trying to make a L+R summer with LP with the least components possible, which also provides the original L and R reparate channels with HP.
Despite both circuits need some adjustment to get the -3dB point coincident, i sort of get what i want, but when i connect both things in parallel to the AC generator the filters go mad. It may be an awfull abomination but this is as far as i got, is there an easy way to isolate both circuits if they share the signal, or my attemps are worthless altogether?
In the pics u ll see the buffer for the L and R with HP and the L+R and then the awfull altogether stuff. Besides adjustmets, it just fails to work altogether when joined:
Here just the LHP:



Here the L+RLP: (incredibly DC is at about -2.5V)

And here the little frankenstein:

Getting new headphones so these jubilee seem good for under $200 input appreciated.

I'm working on my 1st PA subwoofer project which is based on Void Stasys X-Air design.
The plan is to use two B&C 18SW115 woofers instead of the original Void drivers.

Subwoofer design overview



What I'm currently concerned the most about is:

- Circular ports length / rear chamber tuning frequency
- Maximum allowed cone excursion
- LP and HP filters setting

All of these settings depend on each other in some way.

As I don't know how to model this acoustic system as a whole (maybe possible in akabak) I used Hornresp and WinISD to model the subparts of the subwoofer.

Advices/comments/corrections/upgrades of my analysis are more than welcome! 🙂

General setup

Drivers: 2 parallel
Rear chamber volume: 197 Liters
Filters:
LP, Butterworth, n=4, cutoff=140Hz
HP, Butterworth, n=4, cutoff=40Hz
System input power: 6.8kW (134.2V each driver)

WinISD settings



Subpart 1 - circular ports - WinISD

There are four D=101mm circular ports going from the rear chamber.
I modelled the port length and rear chamber tuning frequency in WinISD.

Circular ports



Setup

Tuning freq: 35Hz
Ports: 4x circular L=31.7cm D=10.1cm

WinISD results - transfer function magnitude, SPL, cone excursion

I am having few of my PA devices variants which are running in multiple cascaded mode for generating up to 150Vrms grid music power. This topology is not economical for sure, but nobody care about economical in HIFI i guess... 🤣

Audiophiles like voodoo engineering approaches for their devices, and I thought of an idea which some might find it very fun and would like to share it. -- A cascaded MA12070P on an aluminium PCBs. 50hz sine gen from a MCU/CPLD. To make it even more Fun and if you wanted to tell your friends that your wallet is real deep, you can always feed the i2s into an series of isolated ESS9038Pro and multiple mcintosh/gryphons/boulders and use them as a power source.

The Pros of doing this? More perfect sine signal? I don't know, just like most of the voodoo products in the hifi market that can't make any justification. Put a brand tag, a nice CNC chassis and sell it at 50 Grand anytime. And this is definitely work better than most of them I guess. 😀

Try to start a conversation with 'NickKUK'. Type 'Nick' into the recipients box and NickKuk isn't there. Type NickK and he's listed.

I'm planning a small PA-system. I have a mixer, a 4 channel power amp, two passive satellite loudspeakers and one passive subwoofer.
I want to make a passive line-level crossover between mixer and amp, following this: http://t-linespeakers.org/tech/filters/passiveHLxo.html
But how do I combine the two channels out from the mixer into one input for the amp channel for the subwoofer?
I imagine, that I should make two low-pass filters, and then somehow connect the output from them to make one sub-signal.
I don't want to make the low-pass high level after the power-amp. Its clumsy and expensive. I also do want to avoid an active cross-over, having trouble building it and messing with a power supply.
Mixer out impedance: 100Ω-120Ω, amp in: 20 kΩ (balanced), 10 kΩ (unbalanced)

Could it be somthing like this? Or is it at all possible to combine two outputs without an opamp?



Your thoughts will be greatly appreciated, as I don't seem to have any 🙂

I've just bought a Grundig fine arts MDC65. It all works fine. There is no remote. Does anyone have a free, downloadable manual or know if, when copying a cd, the separate tracks can be marked automatically or do I need to mark them myself and if so how?.

I have completed Above/Beyond Quantum Power - it is Harmonic/Frequency Theory. Already proven by 2 independent tests . I have 2 designs from the work. One is the SSG-1 Super Generator and the other is the Power Circuit Amplifier, both work by the same principle.. Is anyone making radio valves ? A large size one would be a good prototype, followed by very large models for bigger requirements. All must be completed under a confidential legal contract for protection and preservation. Original work was for E cars but the new theory and work of 55yrs goes into every sector. This work is where Einstein left off. Amplification factor is 10+........

For a tube preamp DC blocking output cap position, what sonic difference does a higher voltage rating in a capacitor provide? In other words, is there any advantage sonically to using higher voltage rated caps over a lower voltage one of the same brand and model / part number, where all else is equal except voltage rating?

There is life after hours --- I usually have 5 to 10 books working at any time. I reserve the last couple hours of every day to tackle one or two. Here's the current list:

"Durer" by Fedja Anzelewsky -- anyone fascinated with sound is probably intrigued by Durer's work.

"Grant's Final Victory" -- Grant's memoirs in his final year, dying from throat cancer. This is a great, short book.

"Coolidge" -- keep cool with Calvin -- he had the personality of a sour pickle but pulled us out of the post WW-I Wilsonian depression.

"Monuments Men" -- I had a friend who was one of these folks --

I picked up a used Boss TU-60 "digital strobe" tuner identical to this one:



In short, you select the string you want to tune and the LEDs will strobe either left or right depending on the pitch of the input; when in tune with the selected note the LEDs will stop moving.

The tuner seemed to work when the rotary knob was set to the high E (1E) setting. However, in the other positions only a single, seemingly random LED would stay lit. If I wiggled/fiddled with the knob it would sometime work very briefly for a couple of seconds. Based on that I figured the rotary switch was the problem.

I took the unit apart, and checked all of the solder joints (it's a single PCB) including those around the rotary switch. Nothing looked flaky. The switch is sealed, so I'm not sure if getting something like Deoxit inside to clean the internal contacts is an option. The only other options I can think of are reflowing the switch contacts on the PCB or just replacing the switch.

I wasn't able to find a full service manual (or even a user manual) for the TU-60 online, but I did manage to find some pics of the front page which lists a part number for the rotary switch (SRN1016S-K15). I went dumpster diving on Google to see if I could source one and got absolutely zero hits.

Any suggestions or additional recommendations for troubleshooting or sourcing a replacement switch?

Hi,

First post!

Is it possible to wind an output transformer for a KT66 valve in single ended?
I have built valve amps before, however I would like to try winding an output transformer. Would a ferrite ring work as a core?
Can any one tell me number of turns and possible size of core.

Regards
M.Gregg

I have a Thorens tD 160 with TP16 arm (mk I i think) a tenant left behind after being evicted. The turntable was subject to moving abuse, the counterweight was on the arm. The outer platter is missing, but the inner platter appears to have not bent the spindle. i haven't put a dial indicator on it or the drive pulley yet, so i don't know if the unit is salvageable.
The tube the counterweight slides on droops down about 2-3 degrees. i'm worried the arm tube is bent, but i don't know how to get the larger tube off to check.

Is there a guide for disassembling and cleaning this arm?

could anyone give me some assistance on identifying these two transistors marking be/ rf and df/rz on the driver board ? thanks !

SOLD SOLD SOLD

Specs: https://www.hifiberry.com/products/ampplus/?amp

Great for kitchen or small bedroom system. Add your Pi, speakers and power supply for a full system that puts out 25 watts. Can throw in Pi A+ Ver 1.0, but you'll need a USB wifi dongle.

$20 includes free shipping.

Hi Everyone,

I have been playing around with this very simple phono circuit. Just two non-inverting opamps with RIAA filter network sandwiched in between. Extremely basic.
My source for the schematic is the Ti LME49720 Datasheet.

Here is my trouble with it: It actually sounds pretty decent (instruments sound correct tonally, timbrally), but compaired to other phono preamps I have lying around, it seems dynamically compressed. I also notice that when I lift the needle at the the end of a record I get a sharp snapping sound from the speakers instead of the usual soft, low "whump." I am guessing that the latter is caused by some hard clipping, and I wonder if my two issues (limited dynamics, and the clipping sound) might be related.

See the schematic below. The design has the gain equally split between the two stages.
I have been pondering a few changes to see if they help:

1- reconfigure the gain ratio between the two stages
2- Add an extra gain stage and split the RIAA time constants between the three gain blocks
3- Add another Op Amp in the first stage and make a cascaded Voltage Amp (each of the two cascaded OPAs run at a lower gain setting to hopefully get more headroom)
4- Get a couple expensive discrete Op Amps for the first stage that can run on higher voltage, thus allowing more voltage swing.

I have never seen option #3 done before with opamps. I assume there are good reasons why, but I don't what they may be.
I am not sure option #1 will get me where I want to go, since I have read many places that headroom is main limiting factor of passive RIAA.
Option #2 is interesting, and easy. I have lots of spare Op Amps.

Sorry for the very basic question. I totally admit to being one of those members with no E.E. background who is constantly "learning." I do suppose it gets old pretty quick.

Best regards,
John

The signal trace shows a 30+ dB drop from input to output around this IC. Looks to be bad.

Tried contacting McIntosh Labs, but they have not gotten back to me in over 2 weeks.

Does anyone have source for this IC? part # 133-002

I have a sharp sx-9700 home stereo amp that has one burned out stk4048ll I was wondering if it would be any kind of gain in power by using the STK4050ll chip.

I have of pair of 2-way speakers, Jeff Bagby's Piccolos, on stands in a rather small room. They are set up in a near field arrangment in a roughly 6.5' equilateral triangle with my seating position. And I have been very pleased with the result. Excellent imaging and sound quality. Particularly with orchestras and opera. I can tell rather well where instruments and singers are located on the stage. There is a sense of 3 dimensional space.

Up to now the speakers have been located about 3 feet from the front wall and there has been nothing between them or on that wall at all. Just emptly space.

Now to please my wife I moved the equipment cabinet from where is was on a side wall to the front wall and centered between the speakers.

And I think that now I perceive a significant difference in the sound field with the equipment cabinet filling that previously empty space.

But before actually stating what that difference is I would like to ask for opinions on what to expect. In brief, if there is nothing on the front wall between the speakers and now you add a 3' high by 2' wide by 2' deep equipment cabinet what , if any, difference would you expect to hear.

Hello, first of all I clarify that I am not an expert, much less. I am modifying this low pass filter, my query is the following because OP recommends me to change the 4558 I thought to use NE5332 or lm4562 you who recommend me

Got this one today and I did a first evaluation along with some DER-EE LCR meter comparison readings. I thought it might be of interest to some of you too. Although little obscure still, its the modern version of Bob Parker's classic in-circuit ESR meter. He redesigned it in 2019 but it started becoming available much later due to the pandemic's disruptions.

This time its of SMD construction with a faster and less power consuming processor. Has captive RG-174 test leads terminated with DMM style sharp point probes. 70cm long from case to tip. There is no zeroing function, no need to delta out the leads resistance due to Kelvin wiring. Two segmented LEDs show value and two simple ones are used for dots. When one dot is lit we are reading in Ohms. When two dots are lit we are in its mΩ displaying range. Dash is on/OL. Housed in a Hammond translucent blue case with over-molded rubbery sides. 11.5x8x2.5cm. Seems rugged enough. Has just one mini push-button, top left located and recessed. For on/off. Will also auto off when left unused for five minutes. Works on two AA batteries.

I found it is rapidly and securely settling for readings. Either for board populated or for free capacitors. It gives dependable ESR results especially in the mΩ range for large electrolytic capacitors (<0.1Ω). Also accurate on tiny value emitter power output or shunt current measuring resistors. I saw on the scope that it uses a 5 uS positive pulse as test signal.
Around 47uF and below, as its 1uF spec limit is progressively approached, it tends to over-read ESR. Surely starts blending some capacitive reactance. Regardless of absolute ESR, the readings even for <10uF values were compatible to those advised on the meter's face sticker for good cap/bad cap fast decisions.

For the little time I used it I believe its a very practical surefooted meter with service work ergonomics in mind. Makes the bad cap hunting job quicker. I would only like bit more supple leads and a kick stand. Of course in the heart of it its just a specialized 0.001Ω-99Ω impedance meter and it should not be used for capacitors characterization work like a fully fledged LCR meter.

Howdy,
I have a Walter Woods Electracoustic MI 200-8 in for repair. I am fascinated how Walter has design such a compact unit for musicans and salesman however, absolute nightmare for a technician to repair!!!
1. Class-D power amp and SMPS designed in the 80’s is a feat in it own! Awesome
2. Hard to get to anything on the any of the pcb boards without pulling every screw to get to components. Components hidden under components.
3. No schematics I know off since Walter keep all tech info to himself possibly not having the $$ to patent the design.
4. All the ic’s and mosfets in power section have been sanded to remove device numbers. ( Lets guess the component game!)

The problem I have is from stone cold, the amp takes 1-1.5 minutes before sound appears?
After initial switch on works flawlessly whilst its its run for a while. Initial check i’ve found the 100K bleed resistors across the main bulk supply are all O/C

Has anyone encountered this fault OR have a schematic to share? Would be greatly appreciated. Happy to keep to myself.

Many thanks
SpeekAudio

I’m thinking of modifying these speakers with Dennis Murphy designed changes, which includes removing the existing tweeters and replacing them with the Peerless BC25. I happen to have a pair of DX25 tweeters that have very, very similar specs other than the Fs,which is about an octave lower in the DX25.
Anyone familiar enough with these mods and/or tweeters to think that the DX25 would be suitable?
Thanks,
Peter

as an example, I was looking at a pic of a Burson preamp/headphone amp.

There seems to be 4 "banks" of circuit for each signal for a fully balanced output?

Thank you.

(I believe the 4 trimmer pots is for the main circuit)

This is for a DAC I/V, using transistors and cascodes in the jocko style. Since it is open loop the main source of error is transistor base current.

I have spent a few hours hunting transistors and have so far found the perfect one, except noone sells it.

So I'd be very grateful if you could share your finds. Here are the prerequisites :

- Vce max : 30V, maybe 20, but I don't need a high voltage part unless it has other advantages.
- Maximum current 100 mA
- Power dissipation 0.2 W (will fry SOT323 chips)
- PNP and NPN, complimentary part would be nice

Now before someone says "BC547C" :

- high hFe (>2-300)
- constant hFe between 5 and 30 mA with the curves to prove it
- LOW CAPACITANCE

See these graphs :

- BC547C gives up long before 10 mA
- BC317/337 would be good but it oscillates in Spice
- ZTX851 starts its linear region AFTER 10 mA
- MMBT489 is perfect but too low power dissipation and high capacitance

Thanks to anyone who can help !

Hello, a pair of infinity kappa-5 speakers I own, make a loud popping sound when played in high levels, especially if there is a lot of bass. At first I thought it was the amp, but I've tested it with a number of amps and this was repeated with all of them. I am hardly putting 20-30 watts in them when this happens, it doesn't sound like clipping or distortion and the cone movement looks fine. The popping is not happening on a specific interval, they sound sporadic. Could this be failing capacitors in the xover ? The speaker wire connections are all secure.

$88 shipped in the US
New old stock -- untested --

Hi guys,
I 'm trying to repair a SMPS from one of those cheap micro systems with cd player etc. Even if it might not be worth the effort, it is kind of a challenge to me.
Hope this is the right board to ask for advice regarding smps.

The input fuse was blown, and the first thing I realised is that the input was shorted. I checked and three rectifier diodes were shorted (marked in red) so I replaced them. There was also a MLCC capacitor 100nf 1kv burned (marked in red) which I also replaced prior to connecting again the power supply. Once this was done, I installed a new fuse and tried the SMPS without load.
No smoke, no blown fuse, everything looked fine, until I checked for the -25v output. It only reads -5v.
I thought maybe the output diode or capacitor was bad. Checked the diode and it works fine, and replaced the capacitor (marked green) for ease of mind. Still -5v output.
The 12v output and 5v outputs measure fine.
Any advice?? What else should I be looking for? My experience with SMPS is very limited but I would love to repair this, since the system has a sentimental value to me.

Thank you;
Fran

$99 shipped USA

Dear all,

Somewhere last year I’ve bought this wonderful amp as a good bargain. It worked ok for about 6 months. After that trouble started. When powering on the amp, you could hear some crackles on the powerbutton. After a while the center and right channel would crack also (like you would turn a dusty volume knob) and once and a while the sound would drop and come back, drop, come back. Switching the amp on and off again (sometimes 2 to 3 times) would “fix” the issue.

The amp was sent for repairing to a well know tech service center. The powerbutton was replaced (no crackles anymore) and the amp was working ok.

After 2 to 3 months again, the channel drops started all over again. Switching the amp on/off would fix the issue. I’ve sent a message to Tony at Parasound, describing the issue, and he told me the culprit would probably be intermittent speaker relays or faulty input level control potentiometers. I had informed the technician about this, but he told me this was not likely the cause. It went back to the service center and after two weeks I got a call that the issue was found (95% sure). Some transistors on the power amp would be causing this behavior.

Got it back again, but even the first time I’ve tested it, the problem was still there. Cgreegg, cgreedd, sound gone, back, gone, back… Now, to solve the issue , I just need to put the volume a bit higher and the sound is back. This worked for about one week.

Yesterday evening, the sound in both channel center and right was OK, but I missed sound from… the left channel!! I did put the volume higher, but this didn’t work. I went to my AV receiver to run the speaker calibration tool and did get the test signal in all speakers right away… after that, the amp worked fine for the whole evening.

It seems that now on low(er) volumes it happens there is no sound, or crackling sound and when putting it up, or sending a test signal everything is back OK.

I can return the amp again (check under guarantee), but I’m at a point that I ask myself to leave it like it is and buy a new amp. Although I’m sure this is a wonderful amp, I’m a bit afraid the cost at the end might be very high and not worth it.

I do understand one need hours and hours to search for a solution, I’m a total noob if it comes to electronics etc and one can tell me everything of course. Given the reputation of the service center, I’ve no doubts about the skills/experience etc… I’m just looking around and getting as much info as possible from other people who are experienced in this audio stuff…

Relays have been tested fully. If I want them swapped, this is no issue, but it will be an additional cost and the technician can not assure this will solve the issue…
I’ve received schematics from Parasound here.
Thanks for any tips, suggestions!
Regards!

hi guys,
I hope somebody has some experience with this component...I'd like to build an amplifier with the stk4241, but I have a +/-30V power supply and a 4ohms load...Is it possible?does it work?an how much power can it deliver?
thanx a lot...
max

Is anybody familiar with the Errorcodes generated by these Denon POA-8000 amplifiers:
https://www.diyaudio.com/forums/attachment.php?attachmentid=874074&stc=1&d=1599483669

The Servicemanual is inconclusive about this and in contradiction with the owners manual.

The "E4' is the most common I've noticed.

Hi!!! Friends need help with an amplifier, I ordered class H amplifier boards, but I searched the entire Internet and there are no diagrams for it, here is a link to this amplifier https://www.elcircuit.com/2019/05/1000w-power-amplifier-class-h-kencleng.html#.XMrpcoeZX7Q.pinterest

Sold

I've designed and built a Maida with a mosfet and LT3080 - that seems to work really nicely. Now I'm looking at developing and building the power supply for my ADC (+15V,-15V, +5V) with the requirement for clocking around 24.756MHz too. I naturally have a large number of questions. The main questions I have are around the power supply - possibly the best option would be having a battery or capacitor bank to provide the ±15V 70mA and the +5V. I'd also create a second +5V supply for the digital side.

I came across this Jim Williams article: https://www.analog.com/en/technical...rement-for-a-low-noise-voltage-reference.html . The interesting piece in this article for me is the low noise power supply, grounding and shielding later on. I've also seen the use of LiPo on here (I'm aware of the issues).

So one option is to use either a bank of super caps or Duracell NiMH 9V D-cell rechargeable to power the ADC. I would probably prefer the supercapacitots and use a current limited power supply to charge, disconnect, then allow the caps to provide power through an LDO. For example an 18-20V super cap bank to give 15V seems reasonable. I could even use the current limiting SMPS bench supplies as the chargers.

For the LDO I was considering LT3045s which should handle 18V. I'd use separate cap banks for +18V, -18V and two +8-12V. The current draw for the ADC supplies would be <100mA each but the +5V digital would be powering a RPI at 2A hence would sendup taking a larger cap bank and parallel.

Has anyone done this already? Any experiences I could learn from?

Hi Guys,
I have a problem on my NR1604, my volume is stuck after using Bubblepnp app. The volume is very low (like -30db) on all network sources. Connecting a physical a source with cables, like a CD player or HDMI works fine. Where I can download the firmware? From what I read this is a know issue and it seems the only way to fix it is to apply again the firmware.
Thank you!

I would like to know if someone can tell me if the SB Audience Bianco-15OB350 can be used successfully in a RIPOL system.
Thanks.

I am hoping to add a pre out to this amp, but I can't find a schematic. From what I've read and see inside, it's basically running what looks like one side of a 12AX7, feeding into an 6SN7 as either a driver or phase inverter for a pair of push pull KT88s.

What is normally the best place I could connect the pre out jack, just after the 12AX7?

As the title says, I have a almost new (tested in circuit for 1 hour) 100K Goldpoint attenuator, that works great and was not cheap! But I changed my application and would prefer a 20K attenuator. It's a long shot, but if you happen to be in the same but opposite scenario, and have a 20K attenuator but need a 100K let me know and we can swap!

I'm looking to see if anyone here has any specific information on the Fleetwood Deville. Love the look of the speakers and I'd like to try to build some myself. It looks as if the drivers are the B&C DE550 1" Compression Driver for the tweeter and the B&C B&C 8NDL51 8" Woofer. Please correct me if those are wrong. What I'm looking for are cabinet dimensions, port dimensions and length, crossover schematics, etc. Any help would be appreciated!

Hello everybody,
I'm thinking of putting an entry in my Auricap Gainclone.

Will I have better sound quality? Or I will not notice much difference?
It's worth the investment? The Auricap cost u $ 27.00.
Thank you.

Hi everyone,

I’m really pulling my hair out trying to find a signal to complete this calibration. My stand alone signal generator can only go as low as 50mv

Procedure from manual below.

I have the Arta software which I can get down to -60db and I also have a 20db attenuator. However the input is to low.

Or am I going about this all wrong. Can someone talk me through this, I’d really appreciate some help with this.

Cheers J

I found this YouTube video on ASMR interesting as viewed through the lens of an audiophile. As explained in the video, ASMR is an auditory response phenomena where certain sounds are perceived as very intimate. Causing a very pleasurable neurological reaction in some listeners. Among other stimuli, ASMR is reported to occur from the sound of some music (mentioned at the 6:30 time mark of the video). Not all listeners seem to be sensitive to the effect. Among those who tend to be sensitive, however, are those who are introverted, or have some degree of anxiety.

I immediately thought about we audiophiles as a group. I’ve always wondered why so many of us are incessantly worried about minute aspects of our systems. About whether the sound we currently obtain could, maybe, be a smidge better if we changed from one brand of interconnect cable to some other brand, or whether our phono cartridge VTA is off a few degrees. Why some of us express the sensation of having an ‘eargasm’ when listening to live music, or to the sound really good playback. Why we are so overwhelmingly male. It’s unfortunate that a gender breakdown of ASMR sensitivity isn’t included in the video.

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*see attached schematic

the LF pre trim for the woofer, the output of which then gets fed to the 1st stage amp, uses a 100uf (nonpolar electrolytic) and a 0.1 uf film cap in parallel

what is the function of the 100uf? to block dc into the amp/ to protect the amp?

what would happen if i removed 100uf and only used the single 0.1uf film cap?

on the HF tweeter pre trim im using a poly/foil cap that sounds very nice and much better than oem

so id like to get the same cap but in 0.1uf for the woofer