Seems like when Sumo went belly-up they took all all their documentation with them. Anyone have a schematic for this unit or a service manual or something of the like? Mine has a non-functional coax input and I believe the automatic on/off isn't functioning properly either. The unit works via its optical input, so hopefully there's just a broken wire or bad solder joint or something along those lines, but if I could find a schematic to check component values against, well, that'd be awesome.

Fully mounted but untested Turntable PSU Set by Meldano with accesories
original threads is:
Microprocessor Turntable PSU Set
€.50 plus shipping and 4% paypal fee.

How can I display diyaudio.com on my smartphone .... i.e., w/o stretccccccccccccccccccccccccch the PC browser version?

This is a heatsink from a Pass ACA. I broke off a screw in one of the PCB mounts and drilled it out. In the end, I decided to buy a new replacement heatsink. So I have this unused heatsink that has a hole drilled out. To use the hole, you would probably have to drill and tap it. Best offer, Chicago area. I am selling other items as well, so I can combine shipping.

Hi all,

I completed my first amp a few months ago. It was more a test than really something to listen to. It used the 9240/240 Mosfets.
Now I want to make a more serious amp, but still keep the cost low and the circuitry simple. I've found a very easy schematic with not much components. I'm going to make a few of them to sell to my friends.



I'm going to add somethings myself; thermal compensation, DC protection, inrush current limiter,..

This is the website where I found it 100 W 8 ohms MOSFET amplifier with IRF9540 - IRF540 | Electronics Circuits Diagrams

I know some of you don't like V-Fets and schematics from that kind of website but what do you think of the circuit? Any major drawbacks?

Thanks

Hi,
Got a board from ebay delivering +V and -V with LM317/LM337.
The input power is supposed to accept both ACin (3-27V) and DCin (5-40V). ACin connection is obvious, but I cannot get any clear help from the seller regarding how to use DCin to power the board. Is it possible to simply connect DCin to the ACin slots? Or should the DCin be connected somewhere else?
Here below are some pics, hope you can get an idea from the scans.
Thanks in advance for any help.

Here's a bunch of parts. All but one are new condition; there's a 50k Bourns potentiometer that was briefly used for testing, otherwise everything is new. The NKK S-339R-ND is worth $17 alone, so there's good value here. Best offer, Chicago area. I am selling other items as well, so I can combine shipping.

I am selling a pair of Visaton FRS8-8 3.3" Full-Range Speakers (8 Ohm). These are open box brand new condition. Best offer, Chicago area. I am selling other items as well, so I can combine shipping.

I am selling a pair of Tectonic TEBM65C20F-8 3-1/2" BMR Full-Range Speakers (8Ohm). They have a few hours on them, just used for testing. Best offer, Chicago area. I am selling other items as well, so I can combine shipping.

Does anyone have a picture of the area around the 494 ?

Someone has been inside this amp before .

The reason I ask is becomes the leds do not work for the high power nor the high current .

I’m not getting voltage to either one

Continuing with my quest for a high SPL studio monitor -

I am wondering what the problems will be with this combination:

JBL 2226H + Beyma 8Cx300Fe



My WinISD simulations show continuous SPL of 113 dB with -3dB point @ ~30Hz (mounted in 2p/half space conditions).



Excursion doesn't seem to be a problem...



And if I am reading this correctly, max power required by the 2226H is <250W..., so I can get by with a Hypex Fa253 handling amplification, crossover and DSP duties...



What are the potential problems with this arrangement?

I was contemplating building a portable speaker system for music and it raised a few questions. If these have been addressed in other threads please let me know.

1- To produce sound we need to move air. For bass, we need to move a lot of air. So larger diameter drivers and higher Xmax will naturally move more air. How is it then that certain cabinet designs can produce higher SPL? For instance I was looking at Bill Fitzmaurice site and how a Titan 48 with a single 15 will produce more SPL than a reflex cabinet with 2x18's. Assuming the twin 18's have similar Xmax, there is a huge cone area advantage and thus more ability to move air...so how does the Titan produce so much SPL? I guess I just have too elementary an idea of how sound is produced.

2- Along the same lines as question #1 and most applicable to the portable project, what design would produce the most bass from a 1-2 cubic foot enclosure? Looking to get down to maybe 35-40hz or so if possible. What general combination would likely work best? Smaller driver in some kind of horn or TL? Larger driver in a simple sealed or ported? I am assuming any given design would require a high Xmax driver.

Thanks

Hello

Is there another way in Ltspice to see the slew rate of a schematic ?

I use the settings like you can see in my image, it show more a square wave than a real slew rate measuring, since the frequency response affect the slew rate square image and result.

Thank

Bye

Gaetan

Hi guys, do you think it will cause any problem?? The rest of the parameters (reverse current, fusing current voltage etc..) are exactly the same. I personally feel it should be ok since its just the rated current capacity. I cant find the 25A one so getting the 35A one instead

There is a fuse at rectifier and it am keeping it the same so i feel it should be enough.

Hi,
I'm talking about JBL... what is the visible difference between an alnico and a not alnico woofer, tweeter?

I checked the forums for this topic, but most of the hits were in the chip-amp forum and nearly all were dedicated to the "how to" of wiring existing, pre-built amps in each configuration.

That's all well and good, but it doesn't help me understand how to set up the design parameters to get the desired output power from the partially designed mono-blocks I'm modifying/building.

I tried the Solid State forum, but got no nibbles. There are a lot of from-scratch designers here, so I thought I'd try asking it here instead.

The situation :
I will have two mono-blocks per channel in an amp I'm working on (in simulation and a single rough prototype). They will be driving an 8 ohm speaker/crossover. I'm looking to get about 50W/ch, and rough math says I should have about half that power in each mono-block, but I'm getting confused with the math, and could use some help.

Two mono-blocks means each supplies half the power, or 25w. The math says to get 25w into an 8 ohm speaker, each mono-block will have to put in about 1.75A driven by 14Vrms. However, the topologies of the two possible solutions require different math...

What I think the solution space looks like :
If I understand Bridged Mode correctly, while we get twice the voltage swing, each amp sees half the resistance. That means we're trying to drive 25w into 4 ohms, and the math gives us results of 2.5A at 10Vrms. Each mono-block provides that much voltage, at the same current, so that's 20Vrms (total) swing at 2.5A, for 50w of power to the speaker.

If I understand Parallel Mode correctly, it is the opposite. Each mono-block sees twice the resistance, but contributes to the total current, so you get twice the current you'd expect for the resistance. In this case, 25w into 16 ohms results in 1.25A at 20Vrms. But each mono-block provides that much current at the same voltage, so it's 20Vrms at 2.5A (total), for 50w of power to the speaker.

The BIG question: Did I get the two circuit topologies right?

If so, bridged looks to be the way to go, from ease of setting up the power supply and modifying the circuit. Getting a clean 56Vpp (20Vrms) signal sounds like a bit of a pain...

Next up will be to get to the output voltage of 10Vrms... from line level input. That will take a total of 30dB in gain (31x gain from 0.32Vrms, consumer line-in levels, to the final output voltage of 10v).

Presently, the amp design gives about 12dB of gain (per mono-block), and I hope to get a fair bit more out of it, but I doubt I'll get all the way to 30dB gain out of such a simple amp design.

So, if I understand this part of the problem correctly, I'm looking at a pre-amp that can punch it up part way. The preamp will have to add (30dB-PowerAmpdB) worth of gain to get from consumer line-out level to 10v, and achieve 50w/ch, correct?

Thanks in advance,
Ken
(yeah, I'm a EE, but I'm digital to the bone - this analog stuff is crazy complicated)

One pair of NIB Community M200 midrange compression drivers. These are 2" throat drivers that go from 400-4kHz, very flat except for a very narrow notch around 3.2kHz. Low distortion. $375.

https://www.communitypro.com/sites/default/files/M200.PDF

I also have one matching SH494 horn. $75, but shipping on it will be expensive due to the size.

https://www.communitypro.com/sites/default/files/SH494_spec.pdf

One TOA HCD-904 horn/compression driver combo. 90 x 40. 630Hz minimum crossover. 16" x 6.5" x 10" (D). $50

Two TOA PCD-690 horns. One with piezo driver, one without. $10/pair.

One ProSystems 4660 1.375" compression driver. $25.

Pair Peerless 811655 1" soft dome, horn loaded tweeters. Around 95dB sensitivity. $45

Photos at link below.

Dropbox - Speaker - Simplify your life

Prices do not include shipping. Will ship international, but I will charge extra for this depending on the amount of unreasonable time it takes to do paperwork. Shipping drive units with charged magnets in them, can require a lot of time, especially if they will be sent by aircraft.

All drive units are located in the Northern California Bay Area.

I have some National LH0002CN , the military version, like the HA can which i am using as buffers in a phono preamp and i think i might have connected it the wrong way although not sure about that.The datasheet doesn't specify if the pin asignement is for the top view or the bottom view, so i thought that maybe the National LF356 in the same can that i have a few might tell the right pins.I used the LF356 pin map in the datasheet to connect them in circuit and now the can get hot within 30 seconds...1 minute after power up without doing anything.Truth is that i am supplying them at +-20v which is close to its max +-22v max supply, its measured voltage output in the circuit is identical with its measured input and in my room it's warm, maybe 30 degrees celsius...I can't connect the thing to a turntable and headphones amplifier right now to check if it buzz out anything, but i wondered if anyone would agree that the LH0002 datasheet pin map is the same with the LF356 and it's the bottom view as in the real thing photo.

Hi,

I want to reproduce single cycle waves (below 200Hz) using a 12" driver (either woofer or subwoofer). As I understand the time domain behaviour of drivers don't allow single cycle sines. With a real life driver, the oscillations take time to build and time to die which is fine for music but not for my application.

Following are some of the ways to circumvent the problem
1) Use a servo controlled driver, servo control has good time domain behaviour.
2) Use multiple smaller drivers, say 8 of 5" drivers, smaller drivers will inherently have better time domain behaviour.
3) Use a driver with very high BL, the high BL will generate lot of back EMF, the high back EMF will allow the amplifier to control the driver better yielding better time domain behaviour. Of, course, very high BLs damp the lows, but thats not a problem since EQ before the amp can bring up the lows, as shown by Don Keele in his paper http://www.xlrtechs.com/dbkeele.com/PDF/Keele (2003-10 AES Preprint) - Nom vs True Eff High BL.pdf

What are your thoughts?

Thanks and Regards,
WA

I have a quantity of these FETs/

Are they any use for audio ?


Andy

Hi, probably a really stupid question but are the led's in this circuit purely for indication purposes or do they serve another purpose. Also why would there be 1 green and one red, is it just to differentiate between + rail and - rail?

[url=https://flic.kr/p/2jq85jw]s-l1600 by matt Franklin, on Flickr[/URL]

Thanks

Matt

Hello there,

I am looking to build a Neurochrome mono amp just for measuring speakers.

Currently I am using an Adcom GFP-565 preamp and Adcom GFA-5002 power amp connected to a Focusrite Scarlett Solo, but I am looking for something more "portable/compact". Ideally it would be half an Adcom GFA-5002/535 with a volume knob and a single input.

There are several possible amp options from Neurochrome, mainly the LM3886 DONE RIGHT and the MODULUS-86 that would fit the bill.

I am not sure which of the two to build, one is easier and cheaper, but I only want to do this once.

What else do I need?

Obviously a power supply, I could either build the Neurochrome POWER-86, or possibly buy the Connex Electronic SMPS300RE. Is there a big difference between the two? What other high quality off the shelf power supplies are commonly used for either amp? Unfortunately Neurochrome has discontinued the SMPS-86 power supply or I would simply buy that.

I see many builds with a toroidal transformer, so I assume I will need one as well?

What type of potentiometer is used for "volume" control, and where would it fit into the signal chain?

Is an INTELLIGENT SOFT START circuit or GUARDIAN-86 MONO SPEAKER PROTECTOR required/highly desirable?

Anything I have missed?

Obviously these are all noob questions and no, I have not built an amplifier before, but I do know which end of a soldering iron to hold and have build electronics in the past.

Thank you,

David.

Hi,

Opening old boxes in my parents' house I've found the following boxed tubes:
4x 1L4
1x 6AQ5
3x 6BQ5
1x 6SN7

Do you have any suggestion on the possible audio projects I could do with them?

Thanks

Looking for to buy CD PRO or CD PRO-2 transport in any condition.

This is in a Nad 218THX amp.

Any recommendations for replacing 2sd1975/ 2SB1317?

(Need to replace all)

Been looking and looks like 1943 / 5200 from ON/fairchaild could be ok. Although freq is at 30mhz instead of 20mhz. ONs are hfe 80, also a version with hfe 50. Not sure what to choose. What difference does it make here. Can’t find exactly what hfe the Panasonics have.

Can i keep everything else the same? Right now res are 0.22R. Bias is recommended to be at 8-10mv
Same with new ones?

Would be nice with just a swap.
Pinout should be same too and to-264 also.

Thx for help

I picked up 3off Crimson FET 2.5 modules on eBay very cheaply and i would like to get them tested/working. Does anyone have a schematic they can share or know the operating specifications for this module? They seem to be a bit of a rarity and not nearly as well-known as the Crimson Elektrik bipolar transistor amp modules. I know Brian Powell has been very helpful in the past and he may have posted these already?. This is not a complicated board so would be fairly easy to trace out the design but it would be helpful to get any information about them from anyone who knows or has a working amplifier already 🙂

Hello everyone,
I have one genuine Philips TDA1541A chip for sale, markings are:

11172
HSH9205 2

The IC is in its original replacement part sealed package.
The scratch you see in in the picture is on the plastic package, not on the chip.

Item location: Italy
I am willing to ship it worldwide.

I'm running bi amped Exposure Super 18 power amps into a pair of Acoutic Energy AE1 mk2 speakers. I'm about to move my racks and will need longer lengths of cable (10m).

I understand my power amps are happier used with a high inductance, high impedamce cable, (I think that they don't have a Zobel network on the output, but don't quote me on this).

I'm currwntly running 24 yr old Linn LK20 for bass and Gale ? silvered for top, but these cables will be to short for my new location in any case.

I'm happy to spend sensible money on cables but not looking at crazy uber wires costing over £5 per metre, esp given lengths required.

Any cable recommendations?
Do I need to worry so much about what I use for the tops?
What in speaker cable terms are considered to be high capacitance and impedance values so I can check Blue Jeans, RS etc?

Any suggestions or advice for suitable cables would be appreciated. Bear in mind I'm no techie.

Hello forum members.
I have been interested in Hi-Fi since early 1970’s and have always had an interest in diy of audio equipment.Now that I am retired I thought I would give it a go.

My name is David. I run a small recording studio, everything paid so I can say no to stuff I don't like. I create my own music, build comps and preamps and also run a site with free pro audio schematics download. Mostly vintage stuff. Creating the perfect sound is always my goal.

I have a pair of small power and output transformers

Power transformers are 480 center tapped at about 60ma 6.3 volts at 2.5 amps
output transformers are 3k to 8 ohms about 5 watts.


High voltage will be limited to about 300 to 320 volts with ss rectifier.
I was thinking about using a 6av5 in triode and 6ab4 as a driver. 6av5 will be biased like a 2A3. Does this seem like a workable idea?

Hi everyone,
I am a music lover in the first place and have been into the audio hobby for about 40 years (more and more enjoying the DIY route in the last 10+ years). I have been following this great forum for quite some time and have enjoyed it / your contributions a lot. Many thanks!

I hope to be able to contribute one or the other thing of interest in the future.

Best wishes,

Norbert

I used to own a small Sony power amp model Ta86 and really liked the power switch. If I recall correctly, it was a 1/4 turn, rotary type with a solid and satisfying click sound when turned.
Do you know where I can find something like this?
I’ll have questions about it’s implementation when and if I’m able to find one.
Thanks for looking

Having read good things about it, I bought some PL33 which is the EL33 equivalent with 19v heaters at 300mA. EL33 is derived from the EL3N which has generated some good reports from users.

So I was wondering about triode operating points, and came up with the attached. I'd welcome some feedback from anyone familiar with EL33 or similar line stages. It's probably not too far away from a 6V6 for example. I'd be using it to drive a 300b.

How do I attach resistance at speaker terminals, use multi meter at speaker terminals and test for dc offset?
Thanks in advance

Bought this a while back and just prefer another DAC more - it is nice as it has that volume control....

How's $425 + ship or pick up in West Sub of Chicago?

Have bought a car SMPS for amplifiers on eBay.
180W DC12V To Dual 32V Boost Power Supply Board For HiFi Amplifier Car Amp | eBay
Intention is to use it in a soundbox with a car lead acid battery.
As I would like to use the 12V from the battery to feed a DSP and BT board, I'm thinking of connecting the input GND of the SMPS with the output GND.
See picture with the red connection. I think the schematic is very similar to the one used for the eBay SMPS.

This way all Gnd is attached to the battery minus pole, creating a common reference point.

I can't think why it should not work .... can anyone else??

Additionally I'll use a small charger based on CN3768 and a laptop SMPS for charging the battery: 12V 3A 1-1000AH Lead-Acid Battery Dedicated Charger Module Board for UPS Car | eBay

Hi there
I am setting up a 3 way stereo, I am 3-amping and is using a DSP to as an aktive x-over.
18" up to 100hz
12" from 100 up to 1400 hz
1" CD from 1400hz and up

The DSP offers me the opportunity to make a time delay for each of the three drivers, so I have so I have sat and listened to 1400hz test tones and steb by step bin aging delay to the 12" driver hoping to hear the test tone getting higher and higher as the sound from the 12" driver is getting more and more in phase with the sound from the 1" horn loaded compression driver.... If then suddenly the level of the test tone is getting lower and lower as I ad delay to the 12" I will start taking back som of the delay added to the 12" driver.
Test tone will be at it highest when time alignment between the drivers is right.

This approach have bin working to some degree, but I juts wonder:
There must be some measuring program that can give me a more precise value for time delay.

I have an UMIK-1 usb microphone.... any suggestions ??🙂

Hi everyone 😀


I've been very interested in waveguide lately. But cant really seem to find my ground.
Since I have a small midrange and an existing 4 way design. I want to build something like it, but with a little different design and more constant directivity. So I found the Seas DXT that is so popular in Kii3 and Grimm Audio, which I also like to listen to, when I visited different exhibitions.
The DXT might be a little to small.... maybe. But I do have a 5" hard cone midrange for the project.
Then I saw on sound imports, that they have guide for waveguides - haha 😛
SoundImports | "Wave guiding" your favorite tweeter. - SoundImports
What if I use the Seas Prestige 27TBFC/G with the Monacor WG300..... would that make a wannabe Seas DXT, but larger?
I can see on Heissmann acoustics, that the DXT can peform well. But since the price is very close - then I could not help to think that this combo might work really well.
Anyone seen someone do this?


Regards

Hey, folks. I review speakers and drive-units and thought I'd share a recent review/test I completed of the Bose 901 Series V. It would take me an inordinate amount of time to copy/paste it all here so to save my sanity I am sharing the link to the review on my site:
Bose 901 Series V Speaker Review

I'm proud of this one. Lots of work and time went in to creating this. About 20 hours so far. But I learned a lot and hopefully others will, too.

This is an interesting speaker, with two different speaker drivers coupled onto one ‘horn’. I’d like to know if this can be simulated fully using Hornresp. And, in general, whether Hornresp allows the simulation of multiple drivers with different T/S in the same horn as well as with sound radiating from the front side of the cone. It’s not a simple TH simulation because there are drivers with different T/S and it’s not a Synergy simulation because there is output from the front of the radiator and neither is it a BLH be because there are two different drivers.

If not, I assume Akabak can do it? I’m unfamiliar with both tools and haven’t found the answer after searching the ‘net.

I’ve no immediate plans to build this speaker from Troels, it is more an example to help me ask about the capabilities of the simulation tools.

Hello All, My first post here.

Writing in from India. recently purchased a 1993 release of Spendor classic 3/5, in transit, one of the mid woofer's frame just Obliterated (not sure about newer ones, but older ones had plastic frames).

i am now left with a pair of 3/5 minus 1 mid woofer. i have been looking for replacement speakers for sometime now (no, spendor cant help in anyway, they suggested i move on)..

anyways, considering spendor made their own woofers back then, this has a diameter of 143 MM, which limits OEM parts for most part except 1 - Morel CAW 538 5" Cast Frame Woofer, this looks like it'll fit right in the rebate provided in the speaker cabinet.

the tweeter on this is a Vifa, so was tempted to consider
1. Vifa PL14WJ-09-08 Woofer Mid Range
2. Scanspeak 15W/8434G00 Discovery

unfortunately, both the vifa and scanspeak are 149mm, and the rebate in speaker cabinet is 143mm...so some woodwork/cosmetic damage would need to be done...

so, the suggestion is need is..
a. which speaker should i go with...assuming i cant do much about crossover settings..neither do i understand how this works
b. if the vifa/scanspeak...any suggestions on how ot do a neat job on rebate...

anxiously looking forward to your valuable suggestions..

Thank you!

Hi DIY audio friends!
Is there someone who tried with Matisse Fantasy preamp, the one from LITE LS27 pcb? There are some MF clones but this one is identical to the original. Does anyone has details about connections or test positions and measurments?
I have a basic schematic and I have almost finisfed assembly ! I am expecting some more items and the bulbs...
Thanks !

Hi ! i have a line preamp solid state with a mains transformer soldered and tightly screwed to the preamp circuits pcb. The transformer is of the type in the picture below

I wonder if its vibrations could in some way cause any noise issues.
I am thinking about mechanically decoupling it in some way from the pcb but it is not that easy because it is designed to be soldered directly to the pcb.
I am thinking about soldering some wires to its terminal and mount it upside down with some rubber sheet/isolators under it
I have seen pictures of preamps where the active circuitry pcb is mounted on a frame on rubber feet ?
Have you ever thought of anything similar ?
Thanks a lot,
gino

Selling my Apogee Stage Magneto-static Panel speakers. In excellent working order. They have been modified by me to work with the internal passive crossover or with external active or passive crossover. Cosmetic condition is fair. As with all panel speaker they need at least 1M from rear wall but can go close to side walls. They were my main system speakers for several years and the only speakers I tried that could better them were Quad Electrostatic ESL-989 which I have now. Derby UK collect only. Limited demo possible within Covid restrictions. £650.

hi i have an Audio Research SP16 preamplifier and i am testing capacitors on the 1uf output.
Originally it brings Rel cap and I have tried Dynamicap and Mundorf evo silver gold and none of these sounds better than the Rel cap they could advise me who is worth it to improve

Hi,
Becasue of pendemic time and more spare time I finished old forgotten PCB project.
This is nothing new (just a shift register),is often used in DIY DAC design.
The assumption of the project was to miniaturize the PCB.
I used chips in TSSOP14 case and RC elements in 0603 case.
The dimensions of the PCB are 23mm x 28mm.
The layout can be configured (jumpers at the botom side) for 16,18,20 and 24 bit DACs.

Regards,
JarekC

I have a AUDIO PRO Image 40 speaker system.
I need to replace (4) 4 inch drivers

Any recommendation for a brand with good quality sound at an affordable price

I have run T/S tests on a pair of 1772's using a Smith & Larson Speaker Tester. The drivers were broken in for one hour a Xmax. Average of three runs each for the two drivers are:

Re ohms 7.28996
Fs Hz 42.59512
Zmax ohms 28.85236
Qes 0.44508
Qms 1.31602
Qts 0.33256
Le mH 0.04414
Diam mm 165.5
Sd mm^2 21512.25
Vas L 72.76948
BL N/A 7.4432
Mms g 12.6453
Cms uM/N 1106.912
Kms N/M 905.7046
Rms R 2.57074
Efficiency % 1.1911
Sensitivity dB(1 watt) 92.76138
Sensitivity dB(2.83 volt) 93.166

The S&L tester does a constant current test, so the numbers will differ somewhat from testers that do constant voltage. The results are not surprising. the Vas lower than published is what I normally see, although I would have expected Qts to be somewhat higher than published rather than lower.



Nothing untoward here. I won't try to explain the glitch at 150Hz for now. I am impressed that there is no reflection off of the surround at ~1000Hz. That big old aluminum phase plug plus (I presume) a shorting ring very effectively kills any impedance rise.

One thing of note: The 1772's suspension is either not progressive or only weakly so. Unlike most Fostex drivers that can't be over-driven to Xsus, it is very easy to bounce the TB off of the back plate. Some care will be required is high SLP low frequency applications.

I will mount these drivers in my FT-2000 cabinet (MLTL). I won't be testing on an EIC baffle, so my FR plots may well have some box defraction artifacts in them, but so be it. It may be a few days before I report back.

Bob

Building myself a tube phonoamp, and I have some questions about earthing/grounding. In phonoamps we have the grounding screw close by where the phono chassie socket are, were the plugs from the TT are connected.
I wonder if this earth/gound point must be isolated from the chassie?
Se my bad drawing...And thanks for a great forum!

It's suggested to use REW and UMIK at 75 db for room and speaker measurements. It's rather loud for my apartment. Can I test it at a lower volume, 12db down or lower?

Also for the auto tune feature in REW, if I never listen at 75db should I be EQ'ing for 75-80 db? Or should it be more in line with my listening levels?

Thanks,
Shawn

I pulled the trigger to the tune of $200 for a pair of Goldwoods, as I thought I could do a little bit better than the Wharfdale 18" drivers I spent $100 on. The Wharfys have a measured fs @40 Hz, otherwise I cannot find any specs on them - other than that they're 4 Ohm speakers.

Checking the Goldwoods, they do fs at ~ 30, just as the spec says. They are 8 Ohms. A reknowned driver for WAW OB use. Replacing the Wharfs and tuning things up, I'm not hearing any difference at all in the bass performance of the system.

They could be returned, but that just seems too "American/Walmart/Amazon" a thing to do, to me. The seller did and the speakers are doing everything they're supposed to do - it's just that $200 worth of difference isnt showing up in my own perceptions. The Wharfdales are actually the better constructed speaker of the two Chinese manufactured units, having a cast frame - vs stamped.

I suppose I'm not the first DIYer to drop some cash on a piece - and hear nothing at all from the additional expense.

The OBs have no H frame for the woofers. Should I make a push to get at least the back tunnels constructed to bring these to a bit better life? I'm using a reverse rising response to 35 Hz starting at about 110, where the top has already started to rolloff. The attached pic shows what the OB looks like.

Thanks!

hi
can i use 4ohm speakers on tda7498?what happen if i use 4ohm speakers?

This may be a square (obsolete) question:
If I was to build something into an non conductive case (acryl, wood, coriander, glass, or even marble), what consequence would this have on the grounding schemes?

My sub started to hum, I noticed that the female RCA terminal was loose and if i position it a certain way it would sound correct. repair should be a walk in a park, just remove the plate amp, solder or glue the RCA connector poof, job done.... until you noticed that the back side of the RCA connector is covered with a black plastic box





Why is there a need to enclose the backside of the RCA ?

Any ideas what to do next, should I remove the box ?

Hi guys

I own a Nad c372 that i have used for several years, and always worked fine.
Recently it has started with a red ligth and no sound at first startup at the day. Then i turn it off again with the remote, and turn it on again and then it works like it should. (green light)

But im thinking that this problem is something that could be a indication off a bigger, and maybe expensive problem.

Any toughts?

Thank

Regards

SOLD - Selling my delightful Elekit TU-8500 tube preamp which includes a solid-state phono-stage. Excellent, inexpensive introduction to separates or someone needing its small footprint. Includes all options (upgraded caps, resistors & phono-stage opamps) I've been using it since building in Dec/Jan and it has been terrific. However, I was offered a high-end preamp I've been lusting after for years at a "too good to be true (almost)" price last month and it is just enough better that am selling the Elekit. I purchased new from Victor Kung at VKMusic, the importer/distributor for Elekit and other high-end boutique Japanese audio exotica. Google VKMusic.CA for further links to tons of excellent info and reviews on the DIY forum and elsewhere.
In addition to the Mundorf MCap Supreme SilverGold coupling caps, includes the Takaman resistors & 2227P opamps.
Am also including your choice of a pair of JAN Phillips or Sovtek LPS tubes (both r much better than stock) with the Chinese originals. And, the installed pair of 4562 opamps that I purchased later and find just barely better than the 2227P option. Either have worked great with my MC cartridges.
I was in the process of gathering parts for the installation of the Muse electronic remote control https://www.diyaudio.com/forums/swap...es-volume.html when the other preamp 'deal' fell into my lap. I will also include the boards & programmed controller/processor chip if the new owner wishes to complete same.
Have been zero issues with the preamp since I started listening to it in early Jan. So good that I haven't bothered tube rolling and only rolled the opamps as a point of interest. There are additional opamps out there to roll should one be interested, including some high-end ones like MUSE01 & Sparkos Labs, who also offers some high-end voltage regulators. Endless fun, should you wish.
Purchaser pays $650 plus actual shipping cost (will ship international) and any Paypal fees.
Thanks.
SOLD

Hi all, sorry for another thread about grounding, I have a layout that’s not like any other I’ve seen here so wanted to double check a few things.

So my plan is to use the output transformer bolt as a star ground (S), then ground the board via the RCA. Do both channels need to be ground¿ there is only one on the official diagrams.

Also, I have three sets of input jacks, all mounted to the chassis and insulated from the chassis by the plastic washers.

The other two (A,B,C and D) are for me to fashion an
‘Input selector’ by plugging in and out rca patch cables, like an old synthesiser.

Do I have to ground them in the same manner, to the star ground¿…
Also the switches for power, UL / feedback and volume all contact the chassis, should I ground them separately or will the fact that they contact the chassis suffice¿

I have used Neutrik SpeakOn connectors to hook up the speakers, there are no exposed metal parts on these, i assume they don’t need to be ground¿

Finally, does anyone see a potential issue with the signal wires being so close to the power at the bottom of the image¿ I’ve shielded them just in case


Here is the top side, I’ll be housing my turntable here as well. The two green cables will allow selection between phono pre amp and a wired connection from my computer. The two holes for switches above are UL and feedback. I’ll hook these up after I power the amp up and test it.

Hi all,, Hopefully not too off topic, but would modding out the 6AV6 to accept a 12AX7, leave me w/the same gain factors of 100?, and might there be any appreciative sound difference? It's a Bogen CHA-10 single ended amp currently w/a 6AV6 mic preamp tube, a 6AU6 for an unused phono section, 1-6L6 & an EZ81 rectifier, headed to the bench to be RnR guitar worthy. So, 6AV6 to 12AX7, same gain>overdrive, same sound?
A waste of energy? Thanks!! Be well all!

Hi, I got a Behringer BXL 3000 Ultrabass Combo and would need a circuit diagram! I have no trouble to get diagrams from Peavey, Carvin .... but no way to contact Behriger! Ex-German company, now seems to be swallowed (?) by a Chines one.... and the only contact possibility I can find is via "musictribe", but this platform does not allow me to register (complaining about wrong "country" and wrong "phone number", whatwever I enter there :-( )
Does anyone have an idea how to get in touch with them?
Still selling their products so there has to be a way....
Regards
Michael

I would like to make adaptors for using sub-miniature tubes in regular 9 pin sockets, so that I could compare the performance of sub-minis with their 9 pin tube brethren.

The 8 pin bases are readily available, for example:
10pc bakelite octal 8pin tube base for 6sn7 el34 power plug | eBay

I’m looking for a base that would plug into a standard 9pin socket, to solder the flying leads of the sub-mini tube to. Problem is I can seem to find any “naked 9 pin bases” for sale. Could someone help?

I have a Kicker SX 1250.1 Date stamp on the board says 2004 3 13

The low voltage rca input on the amp was being finicky, would have to apply pressure on the cables to get it to work properly at times. i decided to take the cover off of the amp to see if i could fix the issue and found some burned MOSFETs in the corner. As far as i know the amp still works, unless it burned as i was taking it apart or right before. They look very damaged. I dont know much about amp repair. Im thinking of replacing all 5 of the IRF3205 transistors in that area.

I dont know much about how amplifiers work.

I dont know which IRF3205 to use, or what else to check/replace.
What kind of thermal tape to use? maybe silicone-rubber?

Any help would be appreciated.

Equipment i have: soldering iron, solder, vacuum de-soldering tool. Car battery. Multimeter. handheld oscilloscope.

Hi,

Any AN EL84 Integrated + Phono C Core users on this forum?

Cheers,

Is this amp good out of the box without modifications. I would use original parts ofcourse.

Has anyone swapped the stock driver for something else? Is there a compatibility issue with the Big Names? I haven’t opened up the amp, so I don’t know how it’s mounted.

Anyone can post which pin is for the DC power input because I would like to use battery power the amp?

Anything can do in the analogue part that can improve the sound?

Anyone have extra Keratherm from previous project they want to let go? I am in Diamond Bar CA 91765 and looking for the insulators for pickup. I only need three pieces.
Pls. PM me and I will provide my contact info. Thank you!
Abe

Acoustic Energy AE100s series upgrade consideration, tweeters mid/bass Scan Speak Peerless Vifa whatever any ideas?

Just wondering if any of you guys have any ideas on this?

I have some AE120 speakers which I feel are very well made, braced, solid and even mass loaded as standard. In general they don't sound bad, pretty good actually especially if you drive them hard. Although at lower levels I have to say they sound a little lack lustre and dull perhaps. I'm looking to upgrade perhaps the tweeter and midrange mid bass to open the sound up a bit. The drivers that's in there apart from looking cool look pretty cheap units I must say. Just wondering if anyone knows any decent units that will drop right in without too much hassle? Looking for a bit more of an real, airy, live sound.

Its a shame really as the speakers look the business with the grills off but I feel the cost of the drivers here was definitely the biggest limiting factor when mass producing these speakers.

The speakers are rated at 150 watts and 8 ohms. The tweeter recess dimensions are 4 inches exact for its sunken look, and the mid bass is 5 1/4 inches exact at the widest edge again for that sunken fit.

I know some of the Scan Speak etc speakers can be extremely expensive units and I would like it to be a reasonably cheap upgrade if I could. But just interested to see what I could use. I have had the Scan Speak D2010 in many production models in the past it is one of my favourites that one, well at least in the speakers I had. I actually had to buy a replacement for one a few years ago which was £50 then I see looking now they are up to near £80, and it wasn't that long ago.

Can anyone give a rough estimate for the sensitivity of two like 15”, 16 ohm, 97 dB 1W/1m, mid-woofers wired in parallel? The configuration is TMM, 2.5-way. The high frequency roll-off for the .5 woofer will begin around the BS of 250Hz or less. Cabs are base reflex est. 18”W x 40”H. Not looking for the sensitivity of the overall TMM 2.5 speaker, just the two 16ohm woofers wired in parallel. Thanks.

Just a noob here having just built my first anything. I took up ham radio a few years ago after retirement but I was never an electronics whiz like a lot of the old timer ham operators. I thought building something from scratch for the first time would be fun and good education.

The simple Monitor Audio Bronze 2's in my office/cluttered ham shack have never sounded this good.

I think my Rogue Audio Sphinx is headed out to make room. Only two sources: a DAC and the turntable. Right now the DAC is direct into the ACA and I'm controlling volume with Roon.

You've got me hooked on the sound! Where to go from here...

Hi,

A friend of mine just upgraded his system and would like to send me his EAR 8L6 integrated amplifier. He thinks that EAR stuff probably has a dual voltage tap in its main transformer so a technician in the States may be able to wire it for 120V, is he correct?

Cheers,

Horacio

Greetings everybody,

i'm running the 500w (real 300w) IRS2092S from two individual 1200w 20a step up converters (ali express link) wich are connected to two individual 12v batterys.

Works great, i didn't noticed anny issues on the first try outdoor playing a reasonable time on full power too.
But back home i'm noticing a "plop" sound and power cutoff when i turn it up around half way. I gave the channel a bit more power from the omnitronic smard-24rca to be able to give it the max 1,5v output voltage, so it might be that the "ploping" wasn't an issue on my first trys because it was still not playing on full power even if turned up fully because the channel of the omnitronic device was just on half power or something. With my NX3000 Amp the box is still doing fine, so there is nothing broken there 😉

I assume the "plop" is caused because of a power breakdown of the step up converters. (I tested using bigger batterys and a lipo at one side, so i don't think the issue is caused by the batterys not giving enough to the step ups).
I thought some capacitors could buffer the power supply for big drains? I'm running the box 30-70hz with heavy dub music, so more sub bass than kick - could capacitors help in this case too?
Secondly i'm not sure if capacitors will work, because a friend told me they block DC. After some web-search i could only find thins like this (ali express link) but they are for AC to DC - so i assume they don't work with dc input?


On the other hand i found a forum post where somebody just used one small capacitor in between the step up and the amp (50w) and it worked great for him. So the DC isn't an issue? If not, i'm asking myself where i need to place them: Cause the Amp is +/-65v i assume i would need to place them on the + and the - way but not on the gnd path?

And fourth: How many would i need? I calculeted that 3amps on 65v (each side) for one second (possible bass puls) would need about 50.000 uF, and i read that small capacitors in paralell have less resistance (and are cheaper😉 than a few big ones - so i would install like 100 470uf capacitors on the + and negative side?! Or will 10 on each side improve my situation well enough (since that would already be a big improvement/addition compared to the few caps on amp and step up).

Hope somebody can give me some advices,
thanks for reeding,
HimG

Newly acquired Cyrus CD XT SE (transport) is failing to load/disc error.
Purchased what I assume is a generic laser/mechanism to replace the cheap 'original' Sanyo SF-HD850 that I assumed to be the culprit for the failure.
(Needless to say....removed diode protective solder 'blob')🙂

Disc is once again, drawn into the mechanism....but fails to spin/load.
Replacing original mechanism.....does same...no spin/load.

Possible of course, that the 'new' laser isn't working??
What about the flexible 'ribbon' connector to the laser....do they fail over time??

Given that the mechanism is accessed from the underside of the Cyrus...does anyone know how I can check the working of the laser please??

Greetings gentlemen😱

For the past month I have been working on a super regualtor project with Jung style topology, but also includes some trick from the golden reference regulator -> Buffered error amp output to the base of pass element.

The error amp is good old ne5534, voltage reference being the Jung Led reference, and for the pass elements Im using NJT4031/4030 pair...

So here is basically what happened while debugging the whole assembly. The positive supply was rather successful, no magic smoke. But something rather strange happend to the negative regulator, when testing with a 200mA step, the output rings pretty badly on the oscilloscope. The ringing stops after 5-6 periods.

In the contrary, the positive reg shows a very ideal response without ringing. Voltage just goes down, negative feedback kicks in, overshoot a little, then voltage returns to the set value. Nothing more.

To tackle this ugly ringing, a few methods was tried, including: Switching pass element to slower bjt, adding input decouple cap, adding output decouple cap(aluminum, of course), increasing local feedback around erroramp. But none of these solves the problem completely, amplitude gets lower and stills rings for a while.

Anyone familiar with this issue? Thanks in advance..

---------------------------------------- Update----
One interesting result: When using the faster driver BJT 2SA2039, the ringing was like 4 time larger in amplitude and lasts longer. When switched to MJE350 the ringing was almost stopped. Reminds me of Mr. Didden once mentioned about the error amp and pass element selection: They shall have different speed so that phase shift wont happen at the same frequency.

Hi everyone.

As far as I know, arcing is caused by a high current through the rectifier tube, which leads to a high anode-cathode voltage drop.

If this is so, will arcing happend if using a 250 Vrms secondary? Even if the full voltage is across the tube, would (in theory) 250 Vrms (352 V-pk) be enough to make a rectifier arc? Let's take a GZ34, compare to its PIV of 1700 V, those 352 V seem nothing to worry about.

Maybe there're other reasons for arcing appart from high anode-cathode potential, like insufficient emission.


Or maybe I'm confusing apples and oranges 🙂

I appreciate any observation on the matter. Thanks!

I am new to this forum and hoping to find some guidance on where to start on a project I have been planning to do. I have no technical knowledge around speakers and their design but have an engineering background and can work my way around some electronics. Was hoping here might be a good starting point.

I have a 70's intercom / radio built into the wall of my kitchen / dining area which I would like to modernize to play music at higher quality as now it has lots of static and generally low quality. Not looking for a super HiFi system, but I would like it to be good not like just some alexa/google home speaker quality. I would like to keep the aesthetic of the device and all exterior features of the unit, but gut out the internals as the inside looks like a circuits lab, project bread board. It would be a plus for the knobs to be functional to some capacity as well. The unit measures at about 17 x 9 inches, and play into an area about 15 x 15 ft wide. I have added some images for reference of the unit on the wall.