Can anyone help please, I wish to buy an obsolete I/C from "Mercado Libre". As far as I can see, they only ship to Argentina and I have no contact there.
The I/C costs about £12 if iv'e worked out the currency there correctly.
Thanks,
Mike.

Hi
As a result of a new thread about Musical Fidelity Ebay amplifier board

I looked up and found the following. MARANTZ MA-9S2 150W+150W 8ohm stereo amplifier kit WLX | eBay

One pair Power amplifier board base on Marantz MA-9S2 amp 300W +300W L17-35 | eBay


Looking at the diagrams they have completly different resister values to each other and the original Amps circuit diagram.
How much difference can the circuit be from an original ?


Has anyone tried either of these items? with success ?.

I have been using some of these boards from ebay and they are quite nice
10pcs Double Side Prototype PCB Tinned Universal Breadboard 5x7 cm 50mmx70mm FR4 | eBay

now I actually need some with continuous traces (instead of isolated islands), something like this
Experiment. Platine 100x160mm Epoxid FR4 Streifenr. 1St | eBay

but double sided would be better. Anyone has an idea where one could get such prototyping PCBs?

Hello,


i tried to build a F6 amplifier with all parts from DIY store. Yesterday i switched on and hear only music from board A!
I measured all resistors of both boards in the installed state without current and found out that the resistor R3 in board B hasn't 100 Ohm but only 37 Ohm! At board A the R3 has 100 Ohm.

Can someone tell me the reason for this?



Thanks.

Hello everyone, I’m hoping to get some guidance on ordering a specific board. I have never ordered boards and wouldn’t know where to begin as far as the info I supply them. My hope is that since they have made these boards for other people that they can just use those files to make more. It’s an open source board, so available to anyone. It’s a replacement for the STK0050 modules, I currently have four receivers that use the STK0050 and turn many away as I refuse to purchase the modules that are most certainly counterfeit.

Here is a link to one at PCBway.
STK-0050-8 - Share - PCBWay

I’m hoping to order a 3-4 dozen that way they should last me a very long time. I like to purchase parts to where I’ll never need to again just in case they go away. It’s why I buy certain diodes a 1,000 at a time or transistors hundreds at a time.

Any chance someone might be able to assist me on ordering these boards? I don’t even know where to find the open source info.

Thank you!
Dan

Hi,

I have the USB DAC connected to the Raspberry Pi. In .asoundrc it's defined as card 2, device 0. Sometimes after rebooting the Pi that USB DAC becomes (aplay -l) card 1, device 0 and audio doesn't go through it. Is there any way to make the USB DAC always use the fixed card number e.g. card 2?

Thanks!

Hello there,

This is my first post here. I would like to ask for help regarding the building of my own turntable. Where can I find some cheap motors and regulators so that my T/T can operate at 33 1/3 and 45 rpm only, and not at any other speed? My power mains are 230V by the way. This will be my first DIY project, and I do not want to mess it up, and I am paying for these, so currently I am on a tight budget.

Regards
Qizhe

I inherited a Cyrus FM6 tuner but noticed it "forgets" the programmed preset stations when I unplug it from mains.

Does anyone know whether there's a battery inside, or a supercap or such?
I have not opened the tuner yet, and I do not have the schematics.

The user manual does not mention the memory at all.

Thanks!

Hello Friends.

I have an Adcom GFP-555 where the power light comes on but there is no sound from any of the outputs.

The output relay does not toggle.

The power LED comes on.

I've obtained the schematic and from what I measure it looks like there is a fault in the power stage.

I've attached the relevant section, my measurements are in red.

Nothing on the board looks burnt.

From looking at the measure points, what would the best course of action be to fix this?

Thanks!

A few weeks ago I was on the EEVBLOG forum.
There was a thread about kicad.

I suggested my own software had some features kicad didnt and got on the end of a lot nasty attacks.

Since then my ebay account has been attacked from various people leaving bad feedback. Things like kicad is free so mine should be better.

kicad is not free, they had $20,000 worth of grants last year which come from taxpayers, so people have already paid for it.

Its probably on a par with about £300 software.

So comparing it with a package that is £4 for a download is grossly unfair to say the least.

Sorry, rant over..........

Lots of options out there, I don't really love any of them.

Bananas - low retention force (usually), no strain relief or insulation support, don't always come with gold plating (important for me), typically providing crappy set screws for wire connection, crimp barrels are non-standard or questionable, solder barrels very rare

Spades - don't always come with gold plating, no strain relief or insulation support, don't work with many kinds of binding posts, sometimes comes with crappy set screws, can slip off binding post if loose (big problem)

Ring crimp terminals on barrier blocks - no strain relief and typically little to no insulation support, no gold plating (but the high compressive forces from the barrier screws mitigates that), risk of short circuiting due to exposed conducting surfaces in close proximity to many wires (could be covered up with plastic sheet)

Speak-On - moderately expensive, no practical solder option while the set screws can (rarely) loosen, silver contact plating instead of gold (durability/contact resistance concern), good strain relief

Proper spring-cage connectors (e.g. Wago) - looks goofy, no strain relief, secure gas-tight spring connections but questionable fatigue life (the springs dig in REALLY hard into stranded wire)

4-pole XLRs with gold-plated contacts - reliable solder connections, low contact resistance over multiple cycles, good strain relief, moderately expensive, decent current capacity (6-10 A per pole), limited voltage capacity for high voltage/high power amps (<50 VDC)

Thoughts?

Quick question on this type of driver boards, aside not having any waveforms (aside audio on pin 1) on any of the pins of the driver board, is there any other checks to determine if the driver board is dead?

thus far:

> I've read through numerous threads, I found some "good" voltages for reference in this thread ( https://www.diyaudio.com/forums/car-audio/286461-soundstream-xxx6500-sound.html ),
I have all those voltages but no R-R oscillation, all referenced to pin 2 on the driver board.

>I have a strong 45hz entering the board, I have audio on pin 9 of the DLI4060B,

>I don't have any any waveforms on any of the other pins on the other chips on the driver board.

Hi,

I was wondering if anybody here has gotten the opportunity to try the new, non-neodymium TangBand W4-1337SDF and compare it with the well-known neodymium SD-version?

Apparently, TangBand decided to make ferro-magnet versions of their popular drivers that previously were only available with a neodymium-motor, probably because of the inflation of neodymium-prices...

At the dutch "zelfbouwaudio.nl"-forum, there is a discussion about how big of an influence this has on the sound of the drivers, since they didn't just put a bigger ferro-magnet on them, but also changed the voice-coil to become approximately the same BL-value (Le=0.027mH instead of 0.015mH, x-max=2,5mm instead of 3mm with the same gap-height...).

Unfortunately, those new ferro-versions aren't available in this part of the world yet, so we can't compare ourselves (we have the neo-SD-version and even the older SA-version laying around)...

Isabelle

Hi all,
I'm having on my bench for repair a Marantz UD-5005 Super Audio CD/DVD Player which seems to work fine, except for the drawer. When it came to my hands, it wouldn't open the drawer at all. I then opened and dismantled the covering and if I gave it some help by hand, it would eventually move partially. I took the drawer out and eventually the motor would start running in both directions according to pressing the button for opening or closing, it would engage the gears with the belt. So, I changed the belt, thinking it might be worn (looked a bit off), but no, it now was opening and closing with real difficulty and would never finish its way (when it closes, it has to lift the optical pickup, which takes some strength). So I lubricated everything. Seems to move all very well now, BUT, the motor still doesn't manage to finish the loading of the CD, it goes to that point where the tray is in, but the pickup is not lifted correctly, and then ejects again after some seconds.

I ended up dismantling the whole drive mech until reaching the drawer motor, gears and limit switch, which are really badly placed underneath, and I have three ideas of what could cause this, but would like to hear opinions of other people with experience, maybe there's even someone who has worked on this model. Ah, I forgot to mention that I have the service manual which is NOT helpful for this: they basically say that if the drive doesn't work (be it OPU or drawer or whatever), substitute the whole thing with a new one! :O :O so sad.

1 - could this be a defective motor? I mean, oxidized parts on motor brushes or something, which makes it not have strength or stall suddenly at some place? I've seen this on old motors, for example Nakamichi tape decks. This is a player from 2010 - would that be odd? But, it really looked like this in the beginning - the motor would only move with help, then started to get better. Then wouldn't improve more. Yes, I tried lots of deoxit spray - no difference. This is indeed one of these shitty tiny chinese NONAME motors. Oh yes. I have to confess I don't like the build quality of this Marantz player, although it seems to be well regarded in terms of sound and picture.

2 - could this have a defective motor drive circuit? The service manual does NOT contain schematics, so I don't know how to check this. Any idea what voltages I could except to measure at motor contacts?

3 - Could this be caused by defective limit switch? It gives strange readings. It has three positions: left and right, which correspond to the open and closed position of tray (where closed actually means: pickup is lifted and disc is clamped), and center, where it open (drawer is on its way). But: even though it has several contacts, they all seem to measure continuity when the switch is outside of center position, no matter if left or right! That doesn't make sense in my head. Again, no schematic for this! Anyone has any idea if this is normal? I think, if this was normal, why bother use a limit switch with three positions (center, left, right?)?

Thanks a lot in advance for ANY commentes, hints, suggestions for this!

Hi, I have some LEDs I would like to have turn on when my Icepower amps output 1volt of music (like my Yamaha p2500 does)...how do I do this?

Good afternoon gentlemen, I have on my table a hifonics brutus amplifier, it already came from another repair shop, replace source and output mosfets (irf3205 and irf3710), as well as replace the hip4080 driver, the amplifier turns on, green light, there is no overconsumption , the problem is that there is no sound, the relay does not activate, and even by bridging the relay I have no sound, any idea where to start looking? Thanks in advance.

Hello , I am planning to make a MTM 3-way active speaker run by a dsp. Using 4 Dayton Audio TCP115-4 , 2 for midrange in a sealed cabinet and 2 for woofers in a passive radiator cabinet. A Dayton Audio RST28F-4 Tweeter for highs. I'm thinking about using 3 Amp Camp Amp's to run it. I will be using it as desktop speakers. I'm sitting not even a meter away. I'm looking for impact and punch. I know class A is known for great control. Do you this will be a good pairing? also will be my first amp build. The speakers will be paired with a 18" 700w rms subwoofer. And if you see any problem with the speakers please say something too , it's only my second speaker build. Thank you in advance.

Very nice, no rips, tears, or holes. No VC rub. 8 ohms with low DCR of 6.4 ohms.$100 +ship

Hi, I bought an MS-4132 sound card, which is a custom version of the sb1040 aka sound blaster x-fi audio. It has 5 LM4880M and 1 33078 op amps, but since i don't have pcb schematics, I don't know what's the 33078 used for and why they didn't use another 4880 instead

I've searched for the pinout of the 4880s and it seems different from the lots of op amps on the market, due to a "shutdown" and a "bypass" pin.
Do you know some good op amps I should replace the lm4880m with (and eventually the 33078, as well) or if those are good enough, considering that the sound card is pretty old?

Hi guys i was wondering if anyone had FRD & ZMA files for the B&C DE-250 driver on a Dayton Audio H6512 6-1/2" x 12" Wave-guide. I am wanting to build a pair of econowaves for my churches recreational room. I would love to be able to play in xsim with the files before buying. Right now the room has some no name pa speakers that sound like crap. Thanks in advance

Both front channels have -4.00 volts on them .

Any ideas on where to start ?

I had to send my little NAD amplifier in for a repair recently and I took out the little bridging plugs and put them in a safe place. I now can't remember what that safe place is and I can't find them.
NAD Australia want $9- for the pair of them plus $25- postage and I'm wondering if using a spare set of RCA connectors with a short fat wire will work better than the current 600mm length of spare cable I am using to do the bridging between the Pre and Power sections of the 325BEE.
Naturally I could simply pay for postage but I'm a tight-**** and also cash strapped at the moment.
If I solder some up does the conductor wire size make any real difference over 50/100mm?
Also is shielding needed?

Hi

What happens when you cut the basreflex tube at an 45 degree angle on the inside of the box?

The tube will have different lengths, how does that effect the behavior of the tube.

What about different cutting angles, how does that influence the output of the tube.

best regards

uwe

Hey!

I have a question regarding adding multiple sound inputs to my pretty conventional 3 way sound system using a set of filters. So currently I have one RCA connector for left and right sides connected to the filters. This is fine when I had just one input, but I’ve also got a TV connected too, and I constantly have to switch the two manually. Is it possible to have two rca inputs connected at the same time and switch between the two? I can connect two directly to the filters, but I worry about the static and unnecessary noise. Is there a way to switch off the one that isn’t being used, sort of just choosing which input I want at a given time?

Speaker filters - Album on Imgur

I have a yamaha C1 power board. The 100V section keeps blowing a 1k resistor. I have new tip40 power transistors and diodes and caps are new.
Here is the schematic. Far left section, resistor marked R2012 and R2011.
I don’t have an Oscope! Can anyone explain this part of the board? TR 2003 & TR 2004 have been replaced also. Thx Guys

Hi George,

I know this isn't tube related , but I bet it would sell well and keep tubelab going along nicely through any down turns .

I would be interested in a 70 db+ amp as I newly realized one can put a put a proper antenna in a building to use nicely with cell phones.

Thanks very much for your great knowledge you have passed on over the years.

Randy

No jazz fans here?

I was about to delete this to do a better search but it won't let me.

In particular I was wondering if any of you were Joey Alexander fans.

Mmmokay, i dare to start a new thread – it's a first so please be patient and if anyone could help, I would be much obliged.

My question refers to the choices of preamplification for a pair of PASS ACAs that I plan to run as monoblocks.
Yes, I am aware that there is a thread with a similar topic, but in fact I don't want to go the DIY road with that one.

I use a pair of very high sensitivity DIY horn speakers, with no crossover and a single RFT driver like this one. In horn enclosures they probably have an efficiency corresponding 98db or more.

But the tweaking demon won't relent. Inspired by an article by Chris Templer at tnt-audio I intend to fit these enclosures with a pair of Goodmans Axiom 201 drivers. It looks like I'm not the only one on diyaudio thinking about this combination, there are even some success stories and a lot of interesting amplification advice as well.

Back to my horn loudspeakers are very... well... loud. For example, when driven with a 2x18 watt Audio Innovations i couldn't listen to them past "10 oclock" on the pot. Of course, with the RFT they are 8ohm but as soon as the Goodmans are going in, they become 15 ohm.

I have two music sources:
1. a DAC (the Denafrips Ares 2) with XLR outputs (this model has no volume control)
and
2. a mm preamp (obviously also without volume control).

A passive whichmagee attenuator or external volume control is what I would like to drop in this combination.
I am wondering if you could comment on my choices.

For instance:
this one that is just a volume adjuster or this slightly fancier one Do you have a suggestion which one to chose?
Other versions even have serveral values to chose from (10K/50K/100K/250K/500K).

Any suggestions?

Do people use a minidsp with their passive speakers? I can’t seem to find any info on people using eq after the passive/amp/eq/ receiver.
Some things like furniture and will effect the response and fixing little things from the response after the fact I could see as beneficial. Are there any drawbacks with adding a minidsp to a passive speaker?

Hi I would like to know if anybody is building or has built an Aleph-X to around this sort configuration..............

1000va 18-0-18 simple POWER SUPPLY 'C'
16 IRFP044N 8A BIAS.................................

I would like to discuss build issues etc ...............
😎 😎 😎 🙄 🙄

I have a working Hafler Se 120. I have attached a schematic and I am trying to figure out how the two transistors circled work together. Also the circled 5.1 ohm resistor does get very warm and I am trying to figure the voltage drop and current through it. This 5.1 ohm resistor is 5 watts not 2 watts as listed. This is more curiosity than anything. Thanks to anyone that can help. Mark

Hello All,

I'm testing a prototype but have some interesting behaviour.

Would anyone have any idea's why I would be getting this weird dip in the port response at the tuning frequency?

Shared album - Billy Jukes - Google Photos

The speaker was sat on the ground and the microphone was located 5cm from the port opening.

This box uses a rear triangular port for other design reasons.

I have tried varying the length but I still get the same dip at the tuning frequency.

The port is only 12cm long and the largest internal dimension of the box is roughly 42cm so I can't see any issues with modes in the port or box.

The box Vol is roughly 25L and is triangular in shape.

The Fs of the driver is 60Hz so I don't see any issues there.

Here's a measurement at 5cm from the port with the same driver in another box with a front, square port of similar area and length and slightly smaller box volume with a wedge-shaped box. No issues in the port response here.

Shared album - Billy Jukes - Google Photos

Any ideas will be grateful

What I Share here is my Remote Volume Control KIT V2.

This is a assembled volume controller with 4 sources selector based on high quality Panasonic TQ2-5V relays.

8 Bits conrol provides 256 STEP variation, with the selected useful 67 STEPs, this attenuator can be adjust from -48 dB to 0 o dB (with a infinite load).
Comparing to my VOL V1, this new version is more friendly to listening.

VOL V1 located here :
http://www.diyaudio.com/forums/showthread.php?s=&threadid=130302


Function & Feature
1. 67 steps volume control without any ¡®POP¡¯ noise
2. 4 sources selector
3. Beautiful LCD display, White code with Blue background
4. Universal remote handset
5. Remote / Manual control
6. Considerate PCB layout
7. 8 PCS high quality Panasonic TQ2-5V relays and VISHAY DALE RN55C resistors
8. Build your balance stereo attenuator easily, you just only need to add another main board
9. Easy to use. Only +5V DC power supply is needed
10. Fully test before shipping


This lit includes:
1. Controller board with LCD display
2. Main board
3. Remote handset
4. Remote receiver , rotary encoder and connecting cables

USER MANUAL is ready to go ^_^
Shipment / Carrier : Hongkong Post Airmail Registered
Payment : Paypal I am a verified Paypal member

Total cost : promotion price is only 65 USD , shipment and paypal fee included

Merry Christmas to all the diyaudio member🙂

best regards
bbp

Received this amp with a blown PS section. Removed all IRFZ48V and replaced with STP80NF06.
Rectifiers removed, because some of them short.


Everything else looks ok.
Without recitfiers it pulls high current.
But it seems, that the Fets are not driven good.
Gate resistors are original 328Ohm,
there are no pull down resistors.
I have on each bank a 10 Ohm resistor at the source, with a cap connected to drain.

Since I have the B+ voltmeter and plate current ammeters, it is easy to observe what my amp is doing under any given situation.

What I have noticed is that the limiting factor is my transformer.

I have come to this conclusion by observing my amp running with different rectifier tubes and, more importantly, different cathode resistor values.

The conclusion, based on my observations, is that lowering the cathode resistors to pull more current through the output tubes simply results in B+ sag.

For example: With a 5AR4 rectifier and 620ohm cathode resistors, my B+ sits at about 430V and ammeters indicate ~57mA of current through the tubes.

Same setup with 560ohm cathode resistors (simulation shows B+ remaining at 430V and tube current going up to 63mA) - my meters indicate B+ drops to ~410V and tube current is up to barely 59mA.

I could be wrong - but what this tells me is that trying to pull more current from my transformer is a lost cause. Also, the transformer runs considerably hotter under these conditions!

It's like when you run an engine at 4 thousand rpm and you are already getting all the torque and horsepower vs. redlining it and getting nothing more than extra heat and a much shorter life.

The sound? Zero difference to my ears. I'll be going back to the 620ohm cathode resistors.

Note: I've also learned that SEAmpCAD assumes a transformer with infinite current capability. I like how PSUD2 accounts for the load and adjusts B+ accordingly. It would be nice to have all that functionality wrapped up in one software package.

What is limiting 1" compression drivers from playing <1kHz at "low" volume

Hi all,

I have a question over how low compression drivers can play.

I am looking at running a 1" CD to sub 1000Hz (lets assume 650Hz for ease of maths) on a horn with a cutoff of 500Hz.

For a driver such as the Faital HF108, it is listed as having a crossover at minimum 1.3kHz, with a power handing of 60w AES. The response plot also shows from 1.3 kHz to 650Hz as a ~3dB drop in mean efficiency (with some ripples happening that low)



FaitalPRO | HF Drivers | HF108 (8Ω)

Assuming that this is excursion limited at this power, if I were to drop to 650Hz (and being happy with the ripple in the horn due to cutoff proximity), for the octave drop it would be able to take 1/4 of the power = 15W. Assuming that I then EQ the +3dB in at the 650Hz point, that halves again to 7.5W maximum power.

Because of other limiting components in the system, I can't see the need to exceed 5W (my eardrums included), so would this technically work?

Or, is there something else I am missing? How would it even sound that low?

Plus! Are some 1 inch drivers better suited to this type of (ab)use than others?

Many thanks in advance,

I figured I'd throw this out there just in case anyone is sitting on a pair of Alpair 12PWs they're looking to sell. I'm going to be ordering a pair soon but figured I'd check here first, just in case.
Thanks,
Mike

" Some of you interested in crossovers may find the current 3WC mkII crossover intriguing and I look forward to your response. "

Speaker Talk

25th February 2021

This is a recent question from Troels for his readers.
I have experience in assembling boxes, but not in calculating crossover networks. Although today there are programs that help a lot in this task, but, I consider that experience is essential.

So the table is set, you just have to sit down to eat ! 🙂

New to the site, be gentle. I only know enough to be dangerous.

2017 Hyundai Sonata, all stock, with a 9 speaker Infinity system that includes a 8” sub in the rear deck. Not bad, at all, though the sub doesn’t always handle every task. Plan: add a single enclosed Kicker sub using a Boss R1100M mono block amp. I have a Scosche 2 channel LOC (LOC2SL, 80watt).

LOC: LOC90 Line Output Converter | Convert Speaker Wire to RCA

Amp: R1100M | BOSS Audio Systems, a Leading Audio & Video Brand

Sub: Kicker 10” Comp? In sealed truck box

I’ve done this set up before in another car - sounded great. But this Infinity system is amplified, and 12 people have told me 14 different things.

I WANT to posi-tap into the sub wires PRE-amp (via the wiring harness, as I have the Hyundai service manual sheets with pics and wire IDs), but WILL IT WORK??

Of course I have zero idea how much juice is going into those wires before hitting the amp and how it will all pan out.

I’d appreciate some relevant replies, knowing I’m using what I’m using, so I just need to know 1) sure, that should work, or 2) uhhh no that won’t work (and why), and then 3) what I would need to do to make it work.

In advance, thanks.

Hello.
I need a potentiometer volume balance for NAD 3240PE.
REGARDS

Hi, i am new to the world of DIY amps. I currently have a jadis dp60l preamp paired with audio analogue donizetti monoblocks. I was wondering which amp is better sounding and more worth to build, symasym or myref C. I can get build both with the same price, so i just wanted to know which one is better to build. Thanks!

For sale are 96 pieces of device feet.
= 24 sets of 4.

43,4 mm diameter // 13 mm tall

I believe the material is PVC, i.o.w. hard plastic, color black.

They are brand new, unused.

Asking € 50 for the lot.

I’m interested in using the Morel TM-4055 but I haven’t been able to find any reviews. I really think the design and my hope is that it would sound like a combination of a CAM-558 and a CAT-308 but the specs are different. Does anyone have experience with it? If so what did you use for a crossover?

I am trying to source some measurements on the Strauss SE-MF-2.1...figured I try my luck and throw a pebble in this pond first...

Anyone know someone with a pair or where a pair is in the united states?

Hi.



Wondered if someone would be able to help me. I'm looking to convert an older wooden box single speaker into a unit that can house an Alexa device and speakers within it. I'm looking for a simple 2 coaxial speaker kit or order separate components so it can all be housed within the unit, and attached to the Alexa via the 3.5amp jack. I'd look decent quality speakers. But thinking under £30 seems possible?. Would anyone know where I could get these bits. Ideally would prefer not to have to solder



Thank you for any help, Dave

G’day

The Mains voltage here in Northern Sydney averages 250V, the upper end of the supposed 230V nominal range.

I have a 220V rated Yaqin MC5881A it’s always given off some heat but sounds great so no worries, she’ll be right.

Recently I had to replace the volume pot and whilst tracing the fault and conferring with various threads here realised the internal voltages are out if spec.

Secondary 376VAC
B+ 474V
Heater is 7.56VAC

There are a number of recommended internal adjusts on this site. However I realise that I probably need a new power transformer.

1) any other suggestions?
2) how do I best find a suitable spec transformer ?
3 anything else to consider?

Phillip

The paper is posted on the Beveridge web site but most of the images are missing. If anyone here has the whole document would you be so kind as to post it here? Thanks very much.

white_paper

Hi
looking for either a 500-600va 4 x 35v
or 2x 225-300va 2x 35v
240v or 230v mains

There are plenty of bookshelf speakers, anyone tried to make bookshelves that act as sound absorbers?
My main sound room is fairly reverberant and some extra absorption would be helpful.
Sound absorbers that double as bookshelves seems like an efficient idea but I haven't seen them, has any one else?

The details are that my room is about 8m x 4m x 3m (not exact multiples) and built on a concrete slab, with concrete brick walls.
Definitely no wolf will blow my house down but the bass modes are pretty severe.
The speakers are on the short wall, 2 subs placed to cancel the first cross modes and vertical modes.
The axial modes are less controlled, the wall at the other end from the speakers is broken only by one door, couple of other doors at that end in the side walls.
Book shelves on the end wall would fit the house layout, I could make it more or less all shelves.
The plan is to make the shelves from steel sheet with a C cross section, the open bottom of the shelf would be used for a limp-mass membrane absorber.
I can fit shelves 200 mm wide, thickness is flexible, maybe 75 mm.
I also plan to install some shelves between the speakers but there's a window so this wall at least has some absorption.
2 extra subs on the far wall is a further option to reduce the first axial mode but I'd like to try the shelf solution first.
The shelves will also provide a bit of extra diffusion and that should help too.
Anyone have any experience or ideas for this?

David

Hello,

I built a DIY 12at7 preamplifier.
The tubes run at 12v.
The issu is that the amount of gain is enormous.
The preamp has a volume control on the input but if I run it to a power amp, the gain is such that even the relay cliking on the preamp blows like a bomb (the power amp has no volume control)
In order to use it, I had no choice but to put a dale volume controls between the preamp and the power amp.
This been said, I was wondering if going from 12v to maybe 7 or 8 would reduce the gain or am I condemned to insert a dale between the premp and the power amp?

Thanks

After a long audio absence, I was curious to build a simple vented or closed bookshelf speaker with a fullranger for my office.

I was lucky to get a pair of Alpair 10.3 cheaply from ebay, so my starting point was this simple box which you can find on MarkAudio's website

http://wodendesign.com/downloads/simpleReflex-103-10p-plan-100214.pdf

Now putting a fullranger into a small box without any sort of filter won't give a neutral frequency response as the baffle step is not compensated.

While I respect MarkAudio's attitude of avoiding filters, this simple speaker design is pretty much unlistenable as it is all treble, with little midrange and no bass output - which is exactly what happens when the baffle step is not compensated.

After tinkering, building and listening to 4-5 different filter designs, I settled for a very simple RL-filter which - IMHO - works very, very well giving a neutral, balanced sound. Of course with such a filter one can only burn away energy, so the resulting speaker does not excel in efficiency.

I like the resulting sound a lot and thought I would share it here, so that others can try it too.

A note on bass: this speaker has decent bass output and I'm personally not missing anything in this regard. I know that the measurement might convey a different picture and one might be tempted to further attenuate mid and high range in favor for more bass.

However, my personal opinion is that full rangers should not carry the load of hefty bass output anyway. The required excursion for low frequencies doubles with every octave going down, which means that the full ranger works at least twice as hard at 50 Hz than at 100 Hz. The result is a strong increase in distortion - which can reach 10% for some transducers. If more bass output is needed I would opt to add a subwoofer and cross it with the fullranger at 100 Hz or so.

As the linked, initial filter-less speaker design is called simple bookshelf design, I termed my variant a quite simple bookshelf design.

Enjoy this little fun speaker, Hannes

PS: attached is a periodic white noise on-axis measurement 10cm from the cone away, 50 averages taken. My measurement chain is not calibrated, so values might not be fully accurate but should give an impression.

BUMP: FS DACT CT2 10K Stereo Potentiometer. Or Best Offer.

I bought this a few years ago to use on my AKSA pre-amplifier. It has maybe 20 hours on it. I soldered the signal wires and there is a small amount of solder on the connectors. There is also a small boo boo where I nicked the plastic outer case with my soldering iron, this nick is small and does not go all the way through the plastic.

$105 Shipped in Canada and Conus. Or Best Offer.

Have some 6N13S and I wonder if anybody out there in "Space" have a schematic of a lineamp/preamp/buffer with this tube? Love the size and the look of this tube, and I want to build myself a preamp. Do not need much gain, so a buffer will be great.

I'm closing in on making some sawdust.

I'm using 1 : 1.618 ratios for the box.


My thoughts are ideally the box is .618 from top to bottom, but I'd like to get the driver up higher.

Would more box resonances happen if driver was right up to the top edge of the box ?

What does the "G" stand for??? Looking for MJ15003G and they seem to be out of stock everywhere? Effects of the pandemic? Have they been phased out?

I was able to find the MJ15003 but without the "G". Is that a big deal?

What about running a 5AR4 at max 250mA? Specifically the Sovtek variety. Anyone have any experience with this? Will the tube provide this current for a reasonable amount of time before failure?

More and more I come across posts which require me to scroll horizontally to read sentences that are 2 feet long. You have to scroll back and forth and back and forth just to read them. I usually get frustrated and just move along.

Is there any way to fix this? I assume it has something to do with the poster, not the reader. None of my posts look like this.

I also see numerous posts where the pics are so large that only a tiny portion of them are visible. Clicking on the pic, which normally enlarges it, actually makes it smaller and, in most cases useful. Again, I suspect this is has something to do with the way the poster is uploading the pic.

I don't recall seeing either of these issues many years ago.

I just got an onkyo a9555 and the mids are a little recessed and it lacks drive. The soundstage is huge but diffuse. A guy named bobwire on audioasylum modded his but didn't post pics.

I have a little experience with soldering and modding but I don't think I can do surface mount components. Any help would be greatly appreciated.

Anyone work on one of these? It has a lot of potential and I like the efficiency of digital amps.

It's not the cables. Lol. The audio and LED meter for the right channel from both decks shows no signal. Can someone please tell me what to check first? I went ahead an reflowed the solder on most of the IC's. No change. Thanks!!!!

I'm looking for a class D amplifier scheme that is a self-oscillating model, that uses an operational amplifier ... but I need a model that uses only N channel mosfet on the output. can anybody help me? I thank you all.

For sale 2x Peerless SLS 830668 10" woofers.
Good used condition, old batch (~2011)
Some dust on the cone, light scratches on the frame (see photos), soldered terminals.

$70 / pair or $40 for one + shipping. Located northeast US

I've got some money burning a hole in my pocket, as my grandma used to say. Rather than p--s more of it away on poor choices in the stock market, I have long toyed with the idea of getting a pair of Danleys for home use. Alas, the biggest impediment isn't money, but the perfectly good pair of Yorkville U15 I've had for about 5 years. These were bought used/cheap and I tweaked them to taste, and actively EQ-ed, they (probably) approach what many DSL speakers could offer, of course, without the latest crossovers and such. "Well then, why are you posting about buying newer speakers if you're not serious?" people may inquire.

Just so. Many of DSL speakers are way overkill for the home, of course. If I had a spare $8K or so, I might spring for the classic SH50. But maybe something smaller. DSL has a range of much smaller unts that might serve well in the home. The SM60M or SM60F is a likely candidate, but isn't all that much cheaper than the monster SH50, perhaps $2500/each. What about even cheaper? On Ebay there is a pair of the oddly named GO2-8CX, for $1600 open box. This suggests perhaps $1000/ea. new -- very close to what the Yorkville U15 sold for when it was new. If you look at DSL's specs for the GO2-8CX, it is impressive for a 8" co-ax. I'm not familiar with "church" or PA type installations. I'm assuming it could be run from a normal home amp (8 ohm). With their smaller speakers, of course you'll lose the pattern control at lower frequencies. But how important is that, in the living room?

So, throwing out the question: has anyone used the really small DSL speakers for home use? They seem like they would be a good fit, if their performance is anywhere near what is claimed for their bigger brothers.

I was looking at another low cost filter board, from the far east, to complement my active xo project. Budget active 3 way crossover - buy, eval, mod - diyAudio .

I actually wanted a bandpass more than just a lowpass. I wanted to attenuate the subsonic (<20Hz) as it causes wild movments in some types of subwoofers (BR, BP). In addition to setting the lowpass frequency and gain.

I saw a few different designs and settled on this one (see pic). It costs $8CDN but you have to assemble it yourself. It also has the same problem as all of them, no documentation or schematic. The irony is not lost on me. I bought parts to assembly, from probably the lowest cost assembly region in the world.

I bought this one because:
- it has terminal blocks for connections
- it uses a bipolar supply (see other xo), removes DC offset problems
- appears more complex than others (cap count, regulator, 2 dual opamps)
- potential to modify it, if needed (all through hole parts)

Note : there is a better board at Budget active subwoofer lowpass #2, buy, eval, mod that I prefer over the board in this thread.

I recently acquired this power amp with an unknown history but learned through a member on the Audiokarma forum that I might find info on this site. The amp claims 500 watts or 250 per channel, weighs considerably and appears very well built. After cleaning up the exterior I opened it up and found the transformer was loose and some small black plastic pieces were on the bottom of the chassis along with some small but long machine screws. Removed the screws, vacuumed up all the plastic bits, tightened down the bolts securing the transformer, traced those screws to the back of the output meters, sprayed the pots with Deoxit then visually inspected the circuitry for any abnormalities with all appearing fine. Another thing, those heat sinks extend way out and have sharp edges, I've the scratch marks on my arms to prove it!

Powering it up using a DBT with a 100 watt bulb and 8 ohm dummy load per channel with gain pots set at a minimum, the bulb was first bright then momentarily darkened then came back on at about 3/4 the original brightness. there was no Magic Smoke or explosions! That's about all I had time for today but it looks like a promising project.

Found some info on the bias and offset from a restorer online who thought it should be set to 100mv but this applied to the model 200, haven't found much info on the model 400. Do you think the 100 watt bulb is insufficient for testing this powerful amp or should it be a greater wattage? The transformer is massive and rated at 1.5 killowatts, pretty intimidating and approached with caution! I've some info on this and will have to read it carefully before proceeding further but so far don't see any info on how to go about setting the bias or offset, any info regarding doing this would be most appreciated!

Hi,
I'm new to tube amp, and recently bought a antek power transformer to start.
May I ask can I connect two 230v second for 460v output? I draw a diagram to show the connection. Thanks.

https://i.imgur.com/YdqWjSl.png

The links to the BOM on the DIYAudioStore Aleph J amp board page seem to have gone all wonky. The direct link no longer seems to work at all, and the link to 6L6's "illustrated build guide" seems to now land on a random page of a different thread?

It's been some time since I've posted here. But I think this is the right question for this audience. I'm just curious if anyone knows of a measurement work up for the Adcom GFA-5800- the sort of thing you would see Stereophile's J.A. doing in the tan boxes in the equipment review. I have the Adcom supplied Audio magazine review, but it unhelpfully omits any details.

Basically wondering what the measured power output into common loads was, and what is the lowest practical impedance it can play into.

Thanks much!

/Mike

I currently have 4367s and want to start playing with external crossovers, bi-amping, convolution filters, etc. That said, this is my main system and I'd like to maintain the passive crossovers and normal system signal path through my integrated amp as the baseline while I'm not messing around over the next however months (years?!?) doing this.

So I've been thinking about two options:

(1) a custom binding post plate with one set of binding posts for the passive xover and another 4 pole speakon connector that would be direct to the drivers (with protection cap on the compression driver). Then just a simple switch or set of switches to flip between.

(2) pull the xovers out of the speakers and put them in a separate enclosure by the rack and then have one set of cables to the speakers.

Am I crazy, anyone do something similar, recommendation on parts to use, high quality switches? Anything I do the goal would be to not mess with the stock parts such that it could be put back to stock at any time.

Thanks!

I bought a matched set of these tubes on Ebay for $20 shipped to try in my SSE last week. Excellent sounding, maybe the best of all the tubes I have tried in this amplifier.

SOLD - Acoustic Elegance SPB12-8

Bought these new from AE in 2016. They are new in the boxes. And when I say that I don't mean except for that one time I hooked them up or when I test fitted them. They have never had a wire attached or even been taken out of the boxes other than looking at them and taking pictures. In fact 3 of the 4 boxes have not even been opened. They are still sealed with the packing tape applied by AE when they shipped them to me.

I've got 4 matching SPB12-8 drivers.

These were supposed to go in a WMTMW of my own design but life happened and I don't know when I will have a place to use the monsters I was planning to build.

Obviously prefer pick up in the Atlanta area but I'll ship them if you pay for it.


All 4 drivers as a package for SOLD

So the amp works fine, power LED lights, but after about 10 seconds, it fades out. Amp still operating fine.

Same routine if I power cycle the amp.

Will try to trace the drive out, but hoping for advice.

Hey all,

I received an email from Bill at Tubes and More (AES) today informing me that the UBT-2 ouput transformer from One Electron is no longer available. They still have the UBT-1 and 3 in stock though.

Bummer, I had very good luck with the UBT-2 and was looking to build another lower cost 300B.

One more good option for a budget output gone. 🙁

I'm doing a bulk order to stock up some M3 hardware.

Looking for suggestions of some of the more common lengths that I may want to keep on hand?

My DIY AB honeybbadger has been on hold for a few years now, and I'm really shooting to finish it up, and stock up on sizes I may want for future projects.

Thanks,
Tim

Here's the deal...

I'm a relatively novice repair tech who knows how to avoid getting electrocuted and can fix most basic problems with audio gear. I've got a NAD 3020 on my repair bench that I'm fixing for a friend that I could use some help figuring out. I'll give $20 to the first person who gives me the tip that leads to this thing getting fixed. (for realz!) I know it's not much, but I'm not making much on it either, so that's the deal. 😉

Here's the service manual and schematic.

Here's the clues:

• I checked it over for loose components and cracked solder joints. There were a few loose connections, but otherwise (I think) everything's connected properly now.
• I just put 4 brand new power transistors in it (Q615,Q616,Q617,Q618)
• FUSE 3 and FUSE 4 were blown and I replaced them with new 3A fuses
• It turns on
• It passes distorted garbled audio
• Turning the volume control up results in more distortion, but not more volume
• after a few seconds, R643 and R644 start smoking and charring

If you need more clues, just ask and I'll do further testing or take pictures or measurements if you need me to. I just want this thing fixed and OFF my bench! I really will send the money.

Thanks guys!

Hi everybody... First of all, please forgive my bad english...
I would ask advice about a nasty hum problem I have from a 4 channels B1 buffer with two Biino volume control boards I built...
I tried various wiring ways to improve but none worked...
The situation now is what (maybe) you can see from the weird drawing here...
Can you see something absolutely wrong that could cause gnd loops or something?
I used a gnd loop breaker between psu star ground and earth/chassis...
Thank you so much!

PS. The Biino is a relay attenuator you can see here:

Biino MK2 – hifi-electronics.de

I thought this was very interesting. It, amongst other things, exactly describes and shows the device I described with words on here multiple times.
Good to know I am not delirious in thinking it works. ;-)
Basically a very simple multicell horn.

https://www.pearl-hifi.com/06_Lit_A...ilips_Tech_Review/PTechReview-04-1939-144.pdf

Also very, very interesting publication. And a great site PEARL, Inc. Homepage

I’m surprised with how small dispersion correcting modifiers can be and still work well down to 4kHz.
And with how critical exact angle is.

Index of /06_Lit_Archive/02_PEARL_Arch/Vol_16/Sec_53/Philips_Tech_Review