I have tried to read up on this but have failed to find the answer.
Consider a bank of paralleled caps. Is the ripple current rating just the same as 1 X cap, so as per data sheet. Or has it multiplied?
Thanks

Peeps. I had a dead amp board of Primare A33.2 which I failed to troubleshoot and fix. So I would like to use the parts to build a Class A or Class AB amp. It’s a dual monorail so have two transformers. The secondary windings are 44.6v 56v 0 44.6v 56v. I don’t have any VA rating written on it. It’s a 125w amp and I see 10000uf 63v caps of 8 in total. Am thinking to reuse the transformers, power caps, heat sinks and casing. What would you suggest to do. Honeybadger, Pass F6 or another ? I already saw for naim nap 250 clone this is way over and won’t work. Pic of tranny attached

ALL HAVE BEEN SOLD!

I have the following new, never used 500W SMPS units for amplifier supplies for sale:

QTY 2: +/- 35V
QTY 1: +/- 55V

These boards also offer auxiliary DC supplies of +12V, 0V, +15V, GND, -15V that can be used for preamp circuits and fan power if desired.

A tube kit amp I'm working on specifies that the output tubes are a gain tube and a follower to reduce output impedance, and lists the best tube types for each stage. In most commercial amps I see, they use the same tube in all locations, presumably for simplicity? Is the gain tube/follower tube common in most small-signal output stages? Should that affect how I think about tube rolling (ie, expensive NOS tubes in the gain, cheaper tubes for the follower)?

I have two real world examples to share, where I am trying to understand the tube rolls. The first is the Audio Research DAC3, which uses four 6922 tubes in it's output stage (schematic here: https://arcdb.ws/Database/DAC3/ARC_DAC3MKII_schematic_and_parts_list.pdf). I assume V1/V2 are the gain tubes and V3/V4 are the followers, so changing V1/V2 would have the biggest impact on sound?

My second example is the Audio Research SP8 preamp (https://www.arcdb.ws/Database/SP8/ARC_SP8_manual.pdf). It uses three tubes in the line stage and three tubes in the phono stage, as well as two more in the power supply. Notably, they output sections use two 12AX7s plus a single 6922. I don't understand this circuit, and don't really have any assumptions about which tube does what.

Anyway, just trying to get a bit more understanding before I stock up on vintage lightbulbs.

https://diy.midwestaudio.club/discu...gether-minus-meniscus-and-moved-to-detroit/p1

This is a speaker DIY event. I know it's very close, but figured maybe some semi local people might want to come.

I'll have my Monoculus and Bottleships present for demo. I'm not the organizer, just an excited participant that is helping with providing of some gear.

I have a pair of used B&C DE500 8 Ohm compression drivers. These were used in a two way home system. They're a little beat up from laying around my garage for a few years. Both voice coils test good. I'd like to get $70 for the pair plus $30 for USPS Flat Rate shipping to US.

I think R1 (left-hand side) sets the input impedance for the phono stage. It matches the manual's "50k Ohm" value. I presume I could change that if needed to match another cartridge?

In case somebody has questions about my high octane phono preamp (published in the current Linear Audio issue #6), please feel free to ask here or by pm.

I'll try to be helpful 😉

It's a minimalist 3 transistor design, so easy to build. Oh and it also sounds great!

I will later also upload the schematic here.

Hey guys, usually I post amps in here on this forum however, I thought you will like also some unique speakers 😉

I am building speakers similar to B&W 800D, but its not copy nor clone. Its build from scratch by me using non bw speakers. Ofc I saw youtube videos of build process as well as diy copies. I am not doing that, I go my way but I like the design and some features so I am going to use it as a template.

This is going to be build thread of some sort, even though I am in the middle of process, but anyways... I was posting processes I did so far on the local cz forum, but I think this deserves wider presentation 🙂

Begining...

To make this all possible I started with mid speaker as they call it "turbine head". I told to myself that if I am not going to have this midrange speaker enclosure, its pointles to do anything or start by other parts... so I started to draw in Blender, a lot. It looks simple, but modeling really nice teardrop isnt as simple as it looks on first sight. Original b&w is very prolonged and I didn't wanted my speakers to be as big and deep. So I shortened it and modeled for standard speaker size. The result is 42cm deep teardrop with nearly 30cm diameter. First concept below:



I have a friend who is master of 3d printing so he did print these for me out of PLA. Wall is about 7mm thick with trippled outside walls. I didnt wanted exotic materials, because of several reasons: price, and mainly print realiability. This was printed for nearly 2 days a piece. To make very shallow angles printable its impossible to make it as a one print so my teardrops are glued from two parts by epoxy. To make precise fit I printed also small guides and also speaker mount is sandwitched thanks to that. Below a few pictures of wall "cut" from one damaged print and front piece + tear piece prepared for glue:



more glue:



glued it already looked amazing, it had very nice "pearl" shine thanks to print layers, however because of front piece it looked not as good so I had to do something about it. I watched milion videos how to smooth 3d prints but tried my own way as the main point was somehow same. So I sanded all surface by 80grit, then I filled all surface by 2part polyester filler specifically for plastics. A lot of sanding and dirt... i looked like narco baron 🤣



the result was really smooth, but not enough so one more layer and after sanding:



all 3d print raster dissapeared and I was prepared for primer. First coat was like indicator where the bad spots still are so again sanding and more primer coats. After about 4th or 5th coat of primer and water sanding it was absolutely smooth. I was very happy with the result so I knew the main part is acomplished so I started ordering wood and remaining parts. (I'll get back to teardrop later no worries)

Main body

After I modeled whole speaker body in blender I started to export particular parts into autocad to prepare shapes to be cnc cut from mdf. I wanted all internal matrix parts to be cnced because of consistency which would be impossible to be done by hand. Honestly, it was extremely difficult to find company for this small task, I was searching for a month and some not even responded to my emails, some after second mail stopped communication 🙁 terrible. After long search I found some young guys doing something compeltely different than wood but they had cnc and helped me, maybe a luck but finaly I got my parts:



only the matrix parts are CNCed, I did front baffle by myself with mill as well as some other pieces to safe time and money. One particular tricky piece was doing big radiuses on top and bottom edge of the front baffle. So I did some calculations and milled steps to get the rough radius, looked like this:



so i could smooth out and respect the radius I have made radius sanding tool out of cut piece of PVC pipe:



the result using this custom tool:



bottom radius is smaller ~30mm as there is wall continuing by 10° angle and top bigger radius is ~40mm to smoothly continue on 25° top wall.

After I had all the pieces I needed to figure out what to use for curved walls. I've found out, there is a thing called flexible ceiba plywood so i have order a few sheets 8mm thick and let them cut to size. I was a bit worried by how flexible it is but oh my... it is wobbly and bendy!



some matrix putting together:



To make box "standing" at least on a piece of flat part I did small ending at the back flat where the screw holder will go:



more sanding and connecting radiuses:

Hello.
New to this forum. Just completed this streamer: Rasp PI4 powered with PurePi, Fifo Q7 and Transport PI AES . MCLK is conected. Software is Volumio. No signal out to DAC via AES. DAC (Okto 8) not recognized. Using the correct AES cable (110 ohm) Rasp Pi4 was previously being used with no issues. Help?

Hi,

Note: also posted in head-fi but no response.

I wasn't sure about which section to post this in here, so apologies if I've got it wrong.

I have two Buttkicker LFE minis screwed into the frame of my sofa. The sofa is on rubber mats.
The Yamaha RX-V477 LFE output goes into a Y-splitter, one leg going to a Dali E12F sub, the other into another Y splitter connected to the RCA inputs of a Fosi P1 preamp. I've replaced the tubes with 5654W tubes.
The RCA outputs go into an Aiyima A07 amp, with which I'm using a 32A 5V power supply. I have a 48V supply but don't use it because the fan is noisy and it doesn't seem to make much difference.
The speaker outputs of the A07 are connected to about 7m of 2.5mm2 copper speaker cable.

The buttkickers rattle a bit at lower frequencies, a problem that wasn't solved with the rubber feet on the sofa. I have the crossover on the AV receiver set to 120Hz so that the Dali sub can handle lower frequencies, but this also means that I get eg male voices through the buttkickers, which I do not want. Obviously I can buy a crossover and connect the LFE output to it and only send higher low frequencies to the sub and lower low frequencies to the buttkickers, but I'd like to try and do something with the pre-amp and amp, and in any case I still want the main sub to handle the lower low frequencies.

The buttkickers are sensitive down to 10Hz, but the pre-amp and amp only pass a minimum of 20Hz. The pre-amp has bass and treble tone controls, and obviously I have bass on max and treble on mimimum.

I would like to modify pre-amp and amp to pass signals down to 10Hz and nothing above something like 100Hz, and also modify the pre-amp tone controls to amplify a much lower frequency range so the bass knob controls something like 10-40Hz and the treble 40-80Hz. My (somewhat limited) understanding of electronics leads me to believe that I can replace a few capacitors to achieve some - if not all - of my aims.

I'd be grateful for any thoughts, even "you should have read the FAQ, it's all there", "why on earth are you using a valve pre-amp for low frequency transducers?" or "no, not possible, too complicated to juggle caps and resistors". I'm capable of using a soldering iron.

Pics are from the pre-amp (which has tubes, hence the hesitation about which section to post this in).

Thanks!

I've been directed here by a kind member in the tube sub-forum of DIYAUDIO.

I've pulled two output transformers and a power transformer out of storage.

There's clearly a bit of cleaning up to do on the output trannies!







Can anyone recommend a suitable TUBELAB amplifier to build using these pieces of iron?

Output transformer specs:

5K to 8 ohms
Frequency Response 20 Hz to 90 kHz
Maximum DC Bias Current: 90 mA
Primary DC Resistance: 370 ohm
Primary Inductance: 40 H
Part Number Transcendar TT-012-OT

Power transformer specs:

Hello, I've got a yamaha rxv2700 amplifier, which apparently has 140w on each of its 7 channels, I think.
I have a Lanzar max pro 8" 4ohm subwoofer, with around 800w peak and 400w rms.
I'm pretty amateur, how could I run the woofer of the amplifier? I assume I have to bridge some channels to reach the 400w, but I'm not really sure.
I have a crossover for the subwoofer already, just need some help wiring it, thanks!
Back of yamaha rxv2700:

Note: I know that it's supposed to be used as a home theatre amplifier, but I don't have anything else around at the moment, would be cool to get it working.

So my T34B saga continues. Now that my back chambers are re-attached, there is a new issue.

Today, listening to the tweeters with a 1V sine wave sweep, I can hear some fuzz around the area under 1.5k on one of the driver's.

It sounds like a rubbing VC, so I ran quick impedance sweeps on the DATS test setup. Low and behold, it looks like a rubbing VC. The TSPs are also a bit different which shouldn't be on a matched pair of drivers, unless they're only matched for FR and not overall parameters.

My question is, has anyone with these tweeters measured them as a pair and how did they look?

A pair of B&C 18PZB100 for sale brand new in box, never mounted or used - a bargain at $400 + shipping

Excellent in folded horns and bass reflex cabs. Very efficient and low distortion design. One of the best 18" drivers for FLHs IMO.

Please PM with any questions. Thanks for looking!

For sale are two horns with adapters made from Baltic berch by Athos Audio. They are still without varnish or oil so can be made to your liking.

Asking EUR 400 plus shipping from The Netherlands.

Two drivers up for sale, they have only been used for roughly 20 hours in hifi setup. Asking EUR 300 plus shipping from The Netherlands.

SOLD!

Here is another lot of great DIY parts: LM3886 chip amp boards.

There are I believe 17 or 18 of them. NOS condition. These are great for making small amps and having some DIY fun!

Boards are as shown. Also includes a bunch of mica or insulator pads for heatsink mounting and some hardware for same.

Prefer to sell as a lot.

Please PM me if interested.

Hi all. My old Krell KSA300S is in need of new electrolytics. So i want to buy a complete set of capacitors (maybe also the 4x68000 uF in the psu). Would anyone happen to have a list of the all electrolytics (capacitance, voltage rating and physical size)?

Thanks

My question is if i can remove the tone control op amp in this pre amplifier and still run the volume control. It has two op amps, one for volume and one for tone control. Is this already done or tested? all input is welcome... ;-)

Hi,



I bought this pre-amp and connected it to 12V 4A DC power-brick I already had. I changed the 4 grep film caps to Clarity Cap CSA 4.7uF 250V capacitors, changed the two JRC 55320 op-amps to JRC Muses02 and the valves to two matched Mullard M8100 NOS valves. I'm waiting for the two CSA 10uF 250V caps to change the two 10uF electrolytic capacitors between the two op-amps. I measured the potential difference between the anode & cathode on the valves and it's 70V. The valves are specced at 120V. How could I change the potential difference between the anode & cathode to get closer to 120V without changing the heater voltage?

I did notice the polarity was reversed so I just plugged the output red lead from the preamp to the white terminal on the Arcam rHead headphone etc...


Thanks
Haider

For sale truly top sounding speakers from Germany.Coaxial drivers with Horn-TL enclosure.The speakers are in verry good condition.You can drive this with tube amps or tranzistor amps.This speakers have top timing and big sound scene.The new price was by 7000 euro.The price is 1100 eur😵nly pick up,maybe for someone from Austria,Germany or Countrys near Slovenia.

SOLD!

I'm trying to clear out some parts and downsize in preparation for a move. I have on offer one "box 'o ICs". This contains lots of op-amp and signal processing circuits, some class-AB chip amps, plus a component tester, dip sockets, etc. It's all in a large shoe-box that I will repack for shipping. There is an approximate inventory below but I did not count up parts so I cannot guarantee quantities, etc.

I would like to just ship all of this to a single buyer, US only.

Asking $60 with shipping included. Please PM me if interested.

well ...... seems ages ago ,buried in some obscure DiyA Pass thread , after few quickie (on back of napkin) modifications of XYWZwhatever BOSOZ , my budy Lucky Luke (AKA steen) , demanded one little preamp with balls ....

few posts later , LL have some ideas about topology, perfectly good for me , just because I'm good at paper (napkin) and hand calc almost as he is good in making amps ........

little later - I already have some quickie quickie drawn , but somewhat flipped in regard to LL's idea,with added output stage(s) etc.

main reason why I flipped it is because I feel ( well - I rarely think,anyway) that's smart to use some non-audio-fancy-schmanzy Jfet , which is easy to find in near tobacco store, with all other parts .....

well - result is here (lookie lookie schmtc)

crazy process of delivery is also crazy documented in THIS
thread .........

I can just say tnx to entire OFF TOPIC MOB , just because they make my life miserable with regular questions "will it drive F4 " etc .

anyway ......... for first post is 'nuff


schematic:
(next post -The Shunty)...........

EDIT BY MODERATORS:

With Choky's permission, I have created a new thread the is the same as this thread but with almost all Off Topic posts removed for easy reading by those making the project.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=119070

The new thread is closed and possibly won't be updated, so members should keep checking back here for latest info and amusement

Variac

END EDIT

For sale 1 pair of 2SK82 and 1 pair of 2SJ28 Sony Vfets for sale £100 per pair with UK delivery.

Bought from Acronman.

Decided to sell these nice little amps. They were in a chassis with big heatsinks that they just didn't need and I could do with that for a small class A.
Includes the cables /plugs as seen and also the amp IC insulators.
£40

Hi all,

I keep running into people mentioning Blameless amplifier all the time.
Searching on the internet I could only find schematics from Douglas Self articles.

Is this it? and is there a simple LTSpice simulation that tests all of the parameters?

It was not hard to put one together myself, but I only know so much in LTspice so maybe there can be more suggestions on what to measure?
Maybe this can be a good exercise to learn more about LTspice...

Thanks

Hi all


I have a Neutrik A1 audio analyzer up on ebay. The PSU is dead (torroidal trafo need to be replaced) but apart from that it is in very nice condition. It could be a nice repair project for the long winter evenings. Sadly I don't have the time for it, so I'm letting it go.





It comes with a full service and calibration manual as a pdf.



Neutrik A1 Audio Test & Service System | eBay


(I hope it is ok posting it here?)

Two mono blocks with separate regulated Psu.Top sound,in my system better than F5 or F6 that I also build.The bias is set on 1.6A so you become about 30watt in class A.Verry goid parts and top Thel regulated boards ,this psu is better than any standard psu.Verry good caps like Nichicon FG and Kemet big screw on caps.I think to get about 1200 eu for this set,or best offer.The shipping will be high becose the psu weight about 15kg and bouth monos about 12 kg.
For more questions just contact me.

Hello,

I am trying to build a passive crossover for the first time and here is the rough drawing of crossover that I sketched earlier today.

The drivers that I am trying to make use with the crossover are;

Eminence APT50 super tweeter
https://thespeakerfactory.com.au/products/eminence-apt50-horn-driver-1-50-watt
=> Recommended Crossover 3.5 kHz / 12 dB kHz

Eminence Beta 12a Woofer
https://thespeakerfactory.com.au/products/eminence-beta-12a-2-12-speaker-250-watts

Cap & inductor value got from online crossover calculator.

What I do not fully understand is if I put Zobel Circuit corectly in place. I put them in front of woofer and no zobel for tweeter. Am I on the right track?

And, not sure how I can make inductor with 0.73 mH value. Is there a way to measure the inductor value with multimeter by any chance?

Any guidance would be hugely appreciated.

Thank you.

I’m having a cleanup and have the following for sale. All genuine NOS.

SOLD 24 pcs MUR1560G onsemi TO-220. Price EUR EUR 20,-
SOLD 20 pcs MJE3055T STMicroelectronics. Price EUR 15,-
50 pcs MUR860 onsemi TO-220. Price EUR 20,-
SOLD 25 pcs IRFP240 Vishay TO-247. Price EUR 50,-
10 pcs MJ15003G onsemi TO-204. Price EUR 50,-
SOLD 15 pcs IRFP240 International Rectifier TO-247. Price EUR 30,-
25 pcs IRFP244B Fairchild TO-3P. Price EUR 75,-
25 pcs SFP9610 Fairchild TO-220. Price EUR 60,-
50 pcs IRF9610 International Rectifier TO-220. Price EUR 75,-
SOLD 17 pcs IRFP9240 Vishay TO-247. Price EUR 30,-
SOLD 7 pcs 2SJ74-BL Toshiba, Price EUR 20,-
SOLD 32 pcs 2SK170-BL Toshiba, Price EUR 50,-
10 pcs LM3875T. Price EUR 40,-

No partial sales.
All items are bought from Mouser.
Shipping Worldwide at cost for p&p.

PM me if interested

Hi All, new here and looking to get some help troubleshooting a Tube CD player. This is a BAT VK-D5SE tube CD player that uses 4 6H30 tubes for the output. One channel (2 tubes) works fine the other channel has a couple issues I think are related but maybe not. I do have the schematics, and before I go into gory detail and upload the schematics, I wanted to make sure I was in the right spot and could get some help?

Thanks a bunch
jim

I have a 2008 Kicker ZX650.4 that originally was installed on a wakeboard board. It was in constant protect. Found some water ingress on one channel of the power supply FET's. I had to replace the large input capacitors (swollen vents and measured at 10% capacity) and the power supply FET's. I have looked all over the board (top and bottom) for other obvious issues but do not see anything. When I use a tablet as a source, I get audio output, but it seems lower than I would expect. With the gain maxed, it is audible, but much lower than I would expect. I looked through a couple of PapaZBill's posts on similar amps and I've come to the conclusion I need some help identifying some specifics on this amp. The muting circuit seems like a common issue on these amps, but I'm having a hard time figuring out which components are relevant here. Also not sure if have any output means the muting circuit is fine or if it would completely mute it on these amps.

I have rail voltage at the power supplies and at all 4 sets of output transistors (~+/-35V if I remember off hand). The +/- 15V regulators also seem OK. Amp draws about 1.5 amps at idle. I'm not sure what the exact voltages on the exact pins should be at the daughterboard, but I have a mix of the +/-15V, battery voltage, and remote voltage. No components seem overly hot. The gain knob seems to affect the volume, as do the crossover knobs and switches.

Any help would be appreciated.

Hi, i experiment with Torpedo III design (http://www.diyforums.org/Torpedo-III/TorpedoIII-overview.php) and try to get rid of the parafeed capacitor. It turn out that even when i remove those capacitor, the simulation still show that it working fine as the case with capacitor. Assume that the output transformer is air gap, can this really work?

SOLD
Spare set of Miro AD1865 DAC for sale. i2s inputs on board.
Circuit design and board info available here:
https://www.diyaudio.com/community/...2s-input-nos-r-2r.354078/page-72#post-6525201
You need a PSU and I2s source and a pair of single op amp for this DAC to function. I will not be providing the IV op amp, the op amp on the board in the picture is for illustration only.

Price is $100USD, and it covers the registered shipping worldwide from Singapore.
I have sold and delivered almost 30 items successfully to Europe, UK and US with zero problems.
My preferred transaction would be PAYPAL FF only. For members who are unable accept this mode of payment would have to skip this deal, i am sorry.

Important note : I am currently not at home till end of next week or so( about 5 days away), hence i can only ship after i got home.

I will always be happy to buy Miro a coffee as usual, for his generous sharing.

Looking for lundahl LL1540 input transformers. 😎Kind offers are most welcome.☕

Using 2 Arylic Up2Stream Plate Amp 2.1, I intend on building 2 wireless speakers. When I use these speakers together via the Arylic app, one should function as the right speaker and the other as the left speaker. But if I only connect to 1 of the speakers, I would like it to play both left and right channel, so that I don't miss out on anything. How would this be done?

What are the pitfalls if I were to send my line-level UNbalanced stereo audio over the CAT5 network cable?

(I just need other wires of that Cat-5 to send some DC voltage, seems to make sense to then use the network cable for both audio and constant voltage... ?)

Hello.
Let's get down to the gritty on on-circuit board small film capacitors. Is there anything that people think sounds "better" than WIMA MKP, or for that matter FKP, small capacitors that will fit on existing circuit boards where the WIMAs were? I mean there are plenty of fancypants capacitors that won't fit, and there are plenty of Sensitive People for whom WIMAs are inadequate, but I'm looking for a ham sandwich direct-fit improvement if there is one, and if there isn't, that's cool, I'll go with what I have.

Tank yew.

Hello I purchased and mounted the Scanspeak Aperiodic Variovent 290001.

Now I would like to tune it by changing the inner damping material.

Do you know (if you already have done) if it can be easily opened in two parts without ruining the plastic?

The frame looks overlapped or jointed. Thanks

One pair
One opt was used for testing in a Gm-70
Se for just a few hours.
Excellent transformers
I chose to use a pair of Monolith nano-x because the footprint was the same as previous used Monolith S -15’s
Soundwise the Iso opt’s are in the same league as the nano-x… but at half the price.
Asking 1100 euro
Or swap with a pair of iso fc120-5

Hello,

As some DIYers have already seen, i love to build measurements tools.
I have build some times ago a very useful tool, based on the AN83 and AN61 from a Linear Technology.

It's a wideband DC..10MHz RMS to DC converter (AN61) and a very low noise, high-gain, 10Hz-100kHz filtered amplifier(AN83).
This two tools together (or not) are intended to be used for electronics noise maesurements.
I had build it to compare noise produced by differents voltage regulators.

For a this use, the two functions are connected one behind the other, and a DC voltmeter is connected at the output of RMS/DC converter to
display directly the noise level measurement at input of the LNA.
This two function are indépendant but located on the same enclosure.

These tools works fine.So the RMS/DC converter described in the AN61 use an obsolete part, the LT1088.
This part is hard to find, and if you find one you risk to get it at very high cost !
Another issue with this part is it's unabality to doing measurements when signal level is too low.
So, it's practical measurement range is limited to about 10 to 100% of full scale.
On the other hand, the major advantage of this circuit is to allowing measurement at frequency up to 50MHz,
with signal with crest factor very high without degrading the precision.

You can see what does look this first version below.It's a self made PCB.
[Pict1]




Some weeks ago i had decided to make a new version of this tool.
I want to replace the LT1088 with a modern solution and an easy to find part, to make it more buildable.
Then i think it would be an interesting projects to many DIYers...Isn't it ?

Not many solutions exist to doing RMS-DC conversion, above at reasonable cost.
I eliminate the very known log-antilog converter (like AD736) because they are cosly, doesn't have
wide bandwidth, have big error with crest factor increase.

Nowadays, a good solution is to use a new IC from Linear Tech, the LTC1968 (again they !)
This relatively new IC use an innovative way to do RMS-DC convertion.
It allow very good bandwidth of up to 1MHz, very good precision of less than 1% and low cost.
The measurement precision stay very good with low signal level and medium crest factor.
The LTC1968 is also very easy to do work, only few parts are need to be fully fonctionnal.
The only issue is that it only exist in a very tiny SMD package (MSOP8), to require a good soldering tip.
So, unfortunatly for humans eyes it's quite often the case with modern electronics parts....



The main specifications i would ask for each functions of the new measurement tool are :

Common specifications:

* Powered by batteries (+/-6Vdc) or symetric DC supply +/-6V to +/-12V.
* Housed in low cost aluminium case Hammond 1455L1601.
* Standard Europe 100x160mm 2 layers PCB.
* No exotic parts.

1/ Low Noise Amplifier (LNA):

* High gain of 80dB (x 10 000)
* 10Hz..100kHz build-in -3dB pass-band filter.
* Equivalent input noise of about 500nVrms.
* BNC input and output.
* Overload detection.

1/ RMS to DC converter:

* DC to 1MHz measurement bandwidth
* High input impedance 1MOhms/10pF
* Ooscilloscope probe use for x10/x100 attenuation,
allowing extending measurement range.
* 1v/100mV or 1V/V sensitivity output.
* BNC output and output.
* Overload detection.
* AC or DC coupling input.


You can see below the functionnal synoptic of the new projects ERMSDCV2 with above features :
[Pict2]



The LNA doesn't change in the V2, just an overload detection is added, and the possibility to use SMD or DIP parts(dual-pattern).
You can see below the resulting frequency response of the LNA, and it's own output spectrum with shorted input.
(It's not simulation results, but real measurements !)
[Pict3]


[Pict4]


As you see, the measured output noise level of the LNA is about 5mVrms (-47dBV), so it's about 450nVrms reffered to the input (-127dBV)!
(It's the equivalent noise generated by a 150 Ohms resistor at 300°K !)
This very low noise level in this frequency band allow to do measurements in microvolt range. Like regulators noise, amplifiers noise and more.
To achieve this specs, shielding is very important ! An very good power supply or using batteries is recommanded for measuring this level of noise.
50/60Hz line magnetic field can be an issue, so all transformers must be far to the setup measurement, if possible.


The new schematic of the ERMSDCv2 is done, you can download it HERE (pdf file).
The final design in it's hammong box will look like this ;
[Pict5]



And the printed circuit boards will look like this ;
[Pict6]



Actually i start to solder parts on the prototype PCB and wait to receive some missing parts.
Of course, i will post results as soon i will try it.
I hope that new projects will interest many electronics fanatic like me. ;-).

As for the "AN67 10kHz low THD oscillator" and "DIY CS5381 ADC" ,
when the project will be ok i will organize a PCB group-buy for this new design
if some DIYers are interested. 🙂
To follow soon...


Frex.

Up for sale in this mini package:

• Blue Wolverine EF3-3 w/ IPS board set
• 24 Dale CPF 0.5R 1% 3W resistors
• Finished set of pcb mounted aluminum heatsinks
• Full set of Sanken 2SC3263Y/2SA1294Y Hfe matched output devices (sourced from highly trusted DIYA member)

SOLD including shipping within USA only ( payment via PayPal)

I have this Shallco 47 positions switch for a long time but haven't got chance to really build it. My plan is to make a 100K series stereo unit, basing on the parts list provided by Michael Percy.

Since this is my very first time fooling with this switch, I'm a bit confused about some points, hopefully smart guys here could lighten me.

So I count 47 positions in total but according to the list there are only 45 steps, with last resistor ending at 44-45 positions. Does that mean I'll just leave out the last 46-47 positions on the switch unsoldered?

Also, are these photos below the correct way to solder the resistors in series configuration? I found some photos on Google but most of them were in ladder and required a ground ring.

Thank you!

Hi, I assume this is the place to ask for assistance/help with a problem I am having? Not sure if there is another thread that's for the sole purpose of trouble-shooting class d amplifiers?

Anyhow, I have an issue with my Icepower 1200as2 amp module. Just out of the blue it started switching from ON to STANDBY, even when a signal is present. When I assembled this amp together, I wanted (2) LEDS (Blue and Amber) to display when the amp is in the ON mode, then after a few minutes or so with no signal, the amber LED would come on. It had been working fine for a long time, then one day it started. So I unplugged the unit and pulled the top off to see if I could notice anything visually. Nothing stood out. I even disconnected and reconnected the connections that connect to various plug-ins. I then tried it again and it worked for a while, then started doing the same thing. This seems a little crazy to me as I did it once again by unplugging the unit for a day or so, then plugged it back in and it stayed working good for a longer time, but now it's starting to act up again?? I have no idea why! Perhaps someone may know of a solution, as I really don't want to trash it? Any help would be greatly appreciated! Thanks!

Hello all.
I've built from plans before and some enclosures, but this is my first scratch build, and I have some questions.
The build is with a pair of Radian 5210 coaxials, in a 3ft^3 box, and a 4" vent. I have factory SPL graphs and the factory T/S numbers, but I decided to go all the way (within limits) and bought a Dayton DATS3 to get more precise measurements to work with. I also set up my UMIK-1 and ran some sweeps today, super close, right flush with the baffle to try to eliminate as much room interaction as possible lol. I tested in an unlined box, and next I'm going to test again with some decent degree of lining to tame things down a bit.
Here's my questions
1. I took T/S measurements both free air and mounted in my test box. Which set should I use for the crossover inputs?
2. The SPL graph is somewhat different from the factory test (these were matched and tested at Radian), which is understandable since my conditions are so different and they may have either tested free air of infinite baffle, I don't know. But does it make sense to keep playing with lining the box and adding fill until the reading looks as good as possible, and then use those plots in Vituix? It makes sense to me, but I don't know. I'll post some bad photos I took as I was struggling along today, FWIW. The first photo shows the factory results compared to mine, apologies for the amateur graphic arts display. The second is the woofer obviously, the third is woofer/tweeter, and the last includes the port. The reason you see two lines for each in the later photos is because I measured with and without a bunch of panels surrounding the box/mic to see if there was any improvement in taking some reflections out, at least in the higher regions. The most dramatic difference was in the 12-20k region, where the panels definitely smoothed things out a bit.
Thanks in advance.
Bryan

Working or not.

Need help figuring out bias adjustment procedures for vacuum tube amplifier.
A technician told me to check the bias adjustment every 6 months….. problem is I have absolutely no idea how to do it. Furthermore, they charge an arm and a leg every time I bring the amp in.
Any help would be kindly appropriated.

== UPDATE - MARCH 9 ==

PCBs are shipped! Group buy is now closed.


== UPDATE - MARCH 3 ==

Inductor crisis averted! For 4/6 ohm builds, I'm using 10uH Sagami 7G14D-100M. This inductor is getting bought/shipped separately and costs more than the ICE Components part, so pricing has been increased for configurations that use 10uH inductors. Here's the current price list:

4 ohm and 6 ohm card, fully built = $95, w/filter kit = $105.
8 ohm card: $90, w/filter kit = $105
16 ohm card = $95.

If you've already paid, don't worry, I'll absorb the cost difference.

Not many days left to get your orders in. I'm stopping the group buy as soon as the PCBs ship from elecrow, and making my Mouser/Digikey orders.


== UPDATE - FEB 17 ==

Group buy is on! I'll be accepting payments for ~3 weeks, or however long it takes me to get a prototype ordered/built/tested/verified. Once that's done, I'll close the door on payments and order PCBs/parts.

My paypal address is (posted as an image for spam reasons):
[REMOVED - group buy now closed]

Remember to pay in $CAD - if you pay in $USD you're overpaying.
If you're ordering a fully built amplifier, make sure to specify the load impedance (4 ohm, 6 ohm/TI, 8 ohm, 16 ohm)
If you're ordering a PCB + microcontroller, make sure to specify separate-in-a-bag or soldered on - price is the same either way.

Example prices:

- Bare PCB ($8) with TPA3118 ($15) and microcontroller ($2) installed, shipped internationally ($10.50) = $35.50 CAD
- Two fully built/tested amplifiers, 8 ohm ($90) and 16 ohm ($95) plus two hardware/thermal kits ($10x2) = $205, shipped to the US via Small Packet Air ($15) = $220 CAD.

If you're shipping full amplifiers internationally, or shipping within Canada, use the Canada Post rate calculator and message me with the quote so I can confirm it.


== The Weiner ==

AudioLapDance put out a request for a highly configurable TPA3116 card in this thread:

http://www.diyaudio.com/forums/class-d/267039-proper-tda3116-pcb.html

One day I was stuck home in a snowstorm, and decided to bang out a card design that met his requirements. Soon several other people started throwing in suggestions and requests, and the design evolved into something we all feel pretty good about. AudioLapDance himself proclamed "we have a wiener!", and the name stuck.

Here it is:

Top PCB:


Bottom PCB:


Schematic:



== Features ==

- Small size (5x10cm)
- TPA3118 amplifier IC (more on this choice below)
- Everything is easily and quickly configurable - AMx and MODE pin settings, gain setting and master/slave mode can all be set with DIP switches, and a trimmer pot is provided to allow PLIMIT voltage adjustment.
- 2 stereo channels. The card is configurable into PBTL mode if you want, though unlike DUG's card it's primarily intended to be a stereo design.
- "Wideband" PVCC decoupling, using multiple capacitors chosen to provide a low PVCC impedance from "audio to VHF"
- Additional decoupling on the AVCC pin
- Snubbers before and after the output filter.
- Good quality output filter (ICE Components 1D14A, Epcos 32529J film)
`--> Multiple filter options available for purchase: 4 ohm (10uH/1.5uF), 6 ohm (10uH/0.68uF, standard TI configuration), 8 ohm (15uH/0.47uF) and 16 ohm (33uH/0.22uF)
- Good quality film input caps (2.2uF EPCOS film), footprint will also accept 1210 ceramic capacitors and through-hole bipolar electrolytic capacitors.
- Microcontroller-controlled power up sequencing, with an adjustable startup delay to mitigate turn-on pops with unbalanced sources or large input coupling caps.
- Connections provided for a standby switch and a power LED.
- Good ESD protection on all inputs.


== So, uh, why the TPA3118? ==

To make room for decoupling caps.

The TPA3118 is actually the exact same IC as the TPA3116, but with a bottom side thermal pad for PCB heatsinking. Provided you can sufficiently heatsink the TPA3118, it's capable of the same output power and audio performance as the TPA3116.

In this design, the PCB has lots of thermal vias and an unbroken ground plane under the TPA3118, providing a lower thermal resistance than the heatsinks you find on most of the TPA3116 cards out there. By bolting the card to a metal enclosure and putting a thermal pad between the PCB and the chassis cooling can be even further improved.

With no top side heatsink to interfere with them, decoupling capacitors can be brought very close to the TPA3118 pins for improved performance. Achieving the same electrical performance with a TPA3116 would require the heatsink to be machined to provide clearance for the close-in decoupling, or a small heatsink barely larger than the TPA3116 itself which would not be as thermally effective as the PCB here.


== Cost ==

For bare boards:
- Bare PCB: $8.00
- Add programmed microcontroller, either in a static bag or soldered to PCB - additional $2
- Add a soldered on and tested TPA3118: additional $15.
- Shipping is $8 to the US and $10.50 international for up to 4 PCBs, using Canada Post "Light Packet" service. Within Canada, use the Canada Post shipping calculator for a 6x9x0.5" parcel that weighs 1/4lb, shipped from postal code B3Z 1R3, add $3 to whatever it spits out, and PM me to verify.

For fully built/tested amplifiers:
- 4 ohm or 6 ohm: $95 CAD. With filter kit (allows reconfiguration for 4/6/8 ohm options) = $105.
- 8 ohm: $90 CAD. With filter kit, $105.
- 16 ohm: $95 CAD. Add $10 for an 8 ohm filter kit and $15 for a 4/6 ohm filter kit.
- Chassis mounting kit (thermal pad, standoffs, stainless M3 hardware) = extra $10
- Shipping for up to 3 assembled/tested boards to the US will cost $15 using "small packet air" service.

For shipping elsewhere or using a different shipping method, hop on Canada Post - Mailing, Shipping, Marketing, Shopping, Sharing click "find a rate" and calculate the shipping cost for a 6x4x3 inch box, weight 1lb, from postal code B3Z1R3 to wherever you are, then add $3 for packing supplies and PM me to verify.

Thanks for your interest!

Hi all,
I am going to build a PA speaker set to complement my 4 12" subs (fEarFul from greenboy).
I am thinking of a column speaker that will look like (and hopefully sound like) the RCF nlx 24-a
So a beaming speaker featuring 4 8 inch woofers (dayton audio mb820-8 probably). They sound nice and have pretty high efficiency of 94db.
I will use biamping for this set, so filtering is no problem. I would like to cross over around 1.5khz.
I have some trouble selecting a good sounding tweeter and Horn (CD, 90×60)
There are so many models and brands!
My goal is hifi sounding highs, smooth and brilliant with smooth roll off to the sides. It does not have to hit 20kHz, up to 18 is fine.
Colouration should be minimal.
I have qcs rmx amps to drive both woofers and tweeters
I don't have a big budget, I am thinking of something in the 100-200 euro price range per side.

Any tips welcome (also for alternatives for the daytons)!

I have been seriously considering getting back to vinyl. The reasons for this sudden change in listening tastes are documented in my other threads, which I will partially quote here for convenience. There seem to be no other threads on getting back to vinyl, so some may find my experiences here useful, hence these posts.

I assure everyone following this thread that I have everything in place to purchase a decent turntable, I hope to be traveling out of the country to place where they sell records and record players, and purchase one and bring it back: not shipping costs. Yes, a turntable that will not destroy vinyl or even have an such accusations leveled against them.

The steps, then:

• Experimenting with a cheap record player and learning all I can
• Selecting a real turntable to purchase
• Purchasing the thing
• Buying records and enjoying imperfect sound for a while (I haven't got forever)

Recently acquired on of these beasts, been lusting after one since I first read of their existence back in the early 90's. It arrived with all 4 power supply bipolar transistors blown open, rather than sourcing replacements I converted it to use TO-220 packaged logic level MOSFETs, for reliability's sake. It now works well but I can't seem to locate a manual online for it. Milbert's website says to email them and they will provide one, but I haven't heard anything in nearly a week's time and their phone number isn't working either. I know it's a long shot, but has anyone had any interaction with them or have they slowly faded away?

Hi. I've built myself an amplifier, and am happy with the results. In terms of switching on/off I run 230V mains into an Audiophonics soft start module, which has "switching by fugitive pushbutton low amperage or by trigger 2-12V".

So I have a push button switch attached to the +/- contacts of the soft start module "switch" connection (it also has separate +/- 'button' & 'trigger' connections).

I'd like to replace the push button with a touch switch, but I don't understand enough to feel I can ask the right questions.

I bought a non capacitive touch sensor switch - this needs a 3 - 30v DC supply. The sensor has 3 connections DC + In, Gnd, DC Out. I have connected it in place of the push button - well I connected the soft start 'switch +' to the DC + In, and the ss - to DC Out. This allowed the amp to power up, but no on/off unless I switch on/off at the mains.

I expected this to work, but am nervous about damaging equipment if I start playing around with other connection configurations.

Can anyone help?

Thanks

Dear all

I stumbeled across a couple of russian UHF triodes, small ceramic tubes
- ГС-14, GS-14
- ГС-4, GS-4
- 6C17K, 6S17K

These seem to be very linear triodes, working at moderate voltages, direct heated.

Does anybody know anything about their use in tube amplifiers? They could be used for the preamp stage probably.

Thanks for your answers.
Thomas

There were many brands of direct drive TTs in the 70s and 80s. Among many others, Micro Seiki, Luxman, Denon, Technics and Pioneer seem to have been highly regarded back then. What of those brands were considered most reliable?

Thanks

Hi guys!

I don’t wanna get redondant with my post but I was reading my other thread about my living room subwoofer and I wanted to get a little informations on slot loaded-ish subwoofer.


So I designed this living room table subwoofer. But I’m not sure how to handle/make the grille

Here’s the original design with the grille:


Or I can go east and make a fabric grille with a frame like this under the fabric:


But I feel like the grill would be very heavy. And as I want to not have visible hardware (as much as possible) and want to protect the woofer from everything that can happen in a living room with a 2yo.

While wanting to keep vibrations to a minimum, I sketch this version:




I have 2 Dayton um15 for the subwoofer. Will be Powered by 2 behringer inuke 6000.

So I wanted to have feedback / advice / opinions / facts on the slot load design.

The second version could have 1-2-3 slots depending. As long as the top stays solid for table purpose.

What would be the minimum distance between the two driver in order not to be considered a slot and for not having any “down side” of such design?

Should I stick to the 1st with grille?

Table is 16.5x16.5x40 external dimension.
Pannel are already cut in Baltic birch for the first design, but I have some left so I can make minor adjustment for the slot load design if it’s best.

I’ll gladly add any forgotten information if you guys have question.


Thanks!

Sell a Pair of Monolith magnetics Interstage IT05. 1:1. 25ma
Shipping to EU. Only
300€

Likely 550VA, although I'm not entirely sure. Certainly not less than 500VA.

Dimensions are 135*62mm.
120-0,120-0 primaries and
4*26-0 secondaries.

Gives 36V rectified. Will throw in 4 rectifiers, comes with mounting bolt and rubber pad, centre is potted.

£40+£6UK postage

For sale Nos New never used caps in like new condition. 4 pieces for 80 euro plus shipping EU or best offer. For the data look on pictures.

Hi, I’ve heard that if the crossover network is designed properly, reversing polarity of one driver give a deep null at the crossover region on the frequency response. However, what if one does it without measurements, just voicing by ears? Can we detect the deep null by listening? Also, does deep null have any advantages? Are there any designs that are benefit by deep null?

Hello,
I trying repair Genelec s30's.
- its a three way active speaker

- bass, mid, treble has its own amp

- treble unit was short circuited, burning transistors

- no short circuit in the cable or ribbon tweeter

- changed many parts and got it running except bias reads ZERO!

- dc offset is within limits and reacts to trimmer

- bias is 0.00v and doesnt react to the trimmer

- bias trimmer pot is tested and ok, resistors attached to bias circuit are ok, capasitor in bias circuit was changed

- transistors were changed and tested too (with cheap component tester)

- attachment has the schematic and some info

Why bias stays zero and where is the fault?

I have a large collection of 15ips, 2track, NAB copy masters, all boxed with full studio notes.

Many are well known albums, outtakes and a few from US studios alternate mixes etc.

The full set for 'World War II' (Beatles covers by top-artists), Family's Its 6 albums
Frankie Vaughn 'Tower of Strength, 4 track 1/2" - only one - totally unique!
etc etc

I am now 81 and wish to dispose of this collection - about 100+ tapes which will
have to be collected from South East Scotland.

Please be aware that the contents of these tapes are Copyright and cannot be used for any commercial purpose whatsoever.

What I would like to do is exchange for analogue equipment.

Please respond by Personal Message.

I like to share some of my experiences with Yamaha budget Receivers R-S201, R-N303D, R-N402D and the more advanced R-N803D. This may help others to fix some problems I had with these devices.

For all these device detailed Yamaha service manuals can be found for free on the internet (e.g. on https://www.hifiengine.com/).

All these devices use the same NOBLE REB 161 PVB rotary encoder as input for a digital volume control circuit. The device is rated with a rotational life of 50000 to 100000 cycle. Sounds pretty much but on a R-S201 it failed, while using the volume knob the volume jumps unpredictable. Since a replacement part was hard to get I tried to fix it by carefully opening the rotary encoder and cleaning it by using contact spray and slightly bending the contacts. This worked well so far.

All recent Yamaha devices (Stereo, AV, amplifier, receiver) come with a build in protection function, which shutsdown or prevents the unit from starting in case a serious problem (like incorrect voltages in the power supply, high DC current on the output, high temperature, ...) is detected. The Yamaha service manual describes it in detail. In general, it is possible to enter a diagnostic mode or bypass the protection by pressing certain keys (e.g. "Bass+"+"Preset<"+"Power") while powering up the unit. The R-N303D occasionally reported a "PS1 PRT: 135L" error (actual value "135" may differ a little bit each time), which means the PS1 test voltage was too low (135 = 1.75V, expected range is 152-187 = 1,97V-2.42V). The PS1 test voltage is a combination of multiple power supply voltages via a resistor network, the resulting value is passed to an 8 Bit A/D converter (0-255 = 0-3.3V) on a microcontroller. If the value is out of range the unit shutsdown. Of course, there can be many reasons for an incorrect value. Amway in my case the solution was simple. I first verified the PS1 voltage is indeed too low. I verified that the main DC voltage after the main rectifier, which is part of the PS1 voltage, was correct, but then I noticed that all other voltages failed. All these other different voltages are generated from a pretty complex circuit; however this entire circuit gets its input voltage from a resistor series R281-R285 (8,2 Ohm, 2 Watt each). According to the Service manual there seemed to be a modification in the past here ("New Parts" footnote). On my device it looks like if these resistors had already been repaired in the past (perhaps with the modified new parts?) but one of the solder points of one resistor was bad causing temporary failure. After fixing the solder point the device started up reliable. I also noticed that these 5 resistors can get pretty warm (~80C), so these resistors are loaded quite heavily and perhaps may fail.

The R-N303D, R-N402D are budget devices. You get a lot of features for the price, but you cannot expect the same build and sometimes sound quality as from a more expensive device like the R-N803D. I like to mention one important but not so obvious difference. The residual noise floor of the R-N303D and R-N402D is a lot higher compared to the R-N803D. This can become a serious issue in combination with high sensitivity loudspeaker and/or nearfield listening. E.g. in combination with my Lowther Fidelio (~96db 1w/1m) the R-N303D and R-N402D generate an almost unacceptable clearly audible hiss, while the R-N803D is absolutely quiet. The root cause is probably how the volume control is implemented. The R-N303D, R-N402D use a Rohm BD3491FS for digital volume control while the R-N802D uses a Rohm BD34703KS2, which has a 5 times lower residual noise rating (1uV vs. 5 uV). Since that gets directly amplified by the power amplifier section it can make a big difference. So I definitely cannot recommend the R-N303D, R-N402D for listening at lower volume using high sensitive loudspeakers. However, in combination with average sensitive loudspeakers this is no issue at all.

Hello guys i recently purchased this tda 7294. Is it possible to tell if it's fake or orginal by looking at it's physical appearance?

Hi, i have a problem with the pre ADCOM GFP 555 II. After turnung it on, in few seconds i can hear music but after 4-5 seconds the relay switch off and i can hear nothing. If i turn it on again it works for 4-5 seconds and then the switch off again. Any suggestion?

I’ve gotten familiar with Front Panel Designer, but with that I can just make panels, I would still have to figure out how to connect them together. I know it’s possible to submit custom CAD files when ordering cases from the DIY Audio store, but I’m not sure how to produce them, and am somewhat intimidated. What do you suggest?

SOLD

USB-i2S interface card, bought from Aliexpress:
https://vi.aliexpress.com/item/1000004330054.html?spm=a2g0o.productlist.main.23.5f2e2092CrbECs&algo_pvid=47e58dd8-8d76-411e-af1c-4b2ab35f6cfe&algo_exp_id=47e58dd8-8d76-411e-af1c-4b2ab35f6cfe-11&pdp_npi=4@dis!SGD!34.16!32.44!!!24.32!!@2101f01816940057860513282e1225!64748645091!sea!SG!1757846789!&curPageLogUid=49svf1ZLgRC0

Replaced the two crystals to ultra low noise Crystek bought from Mouser in July.

Already configured to take an external 5Vdc, and it is reversible to take the 5Vdc from the USB bus by closing a solder bridge.

US$40, shipping with tracking is included.

Rest in Peace Gary

Saw him with Al Stewart about 10 years ago.

A great player.

https://www.nbcnews.com/news/us-news/gary-wright-singer-1970s-hit-dream-weaver-dies-80-rcna103322

Hi everybody!

For about two years I've been enjoying my Raspberry Pi 4b streamer running Moode player for Spotify streaming, playing local FLAC collection as well as occasional internet radio. I connecti it to the USB DAC Topping D10s which feeds Audiolab 6000A and Fyne Audio F501 floor standing speakers. Having been happy with the overall setup I don't like the clumsy nature of it: too many boxes and not having a proper way to turn it on and off (more of a Raspberry Pi issue). I want to build a single box with a switch on/off button and a touch screen on the front panel as well as an integrated DAC. I would like to run this list of components by those of you who have built their own streamers:

1. ELECROW 7" 1024x600 Touch screen https://www.amazon.co.uk/dp/B076J8ZWFF/
2. Aluminium Chassis 221x150x311mm (WxHxD) https://www.aliexpress.com/item/32462934301.html Its front panel should accomodate the 7 inch display
3. Power management board Witty Pi 4 https://www.uugear.com/product/witty-pi-4/ (for switching the Pi on and off)
4. Khadas Tone 1 DAC https://www.amazon.co.uk/dp/B0824NNGPN (will upgrade to a newer ES3039Q2M board once they become available)

I have several questions regarding the setup:

1. Can you advice on the suitable power supply? I do not think I need a fancy linear one, but a switching power supply with two separate outputs for both Pi and the DAC would be useful. I am also thinking to implement a trigger output to control the amplifier for which I presume that I need a 12V output. The Witty Pi 4 board has a DC/DC converter and accepts up to 30V.
2. Is Khadas Tone 1 a reasonable DAC and will it not be a downgrade compared to my current Topping D10s?
3. Where can I buy power on buttons to install on the front panel as well as USB and Ethernet sockets (extenders) for the back panel?

I'm pretty new to this and I hope I didn't say anything silly. Cheers!

Greetings all,

I had built an amplifier wherein a diamond buffer (BUF634) is enclosed in an operational amplifier feedback loop (OPA1656), cf., https://www.diyaudio.com/community/threads/opa1656-buf634a-headphone-amplifier.396571/#post-7316599.

I was wondering, whether the amplifier will drive a compression driver on a wave-guide with measured SPL of 112 dB/W/1m, as the specification sheet claims 250 mA continuous output current, which into 8 Ohms would give P=8*0.25^2=0.5 W.

Before connecting the amplifier to the compression driver, decided to measure its performance into a 10 Ohm precision resistor. Using a 1,000 Hz sine-wave I was increasing the output voltage and the amplifier, powered from +-12 V power supplies, worked up to 7.2 V peak-to-peak (p-p) when the sine-wave started to be limited. That seems questionable as the current is I=(7.2*0.707)/10/2= 254 mA, which I interpret as “continuous”. Given the temperature of the case, see next paragraph, current limiting should not occur, cf., Fig.10.

What I further do not understand is that decreasing the voltage to 7 V p-p, causes the amplifier to work for hours, with the case temperature of the BUF634 being stable at about 51 deg C. It makes no sense from power dissipation perspective, because Junction to top of the case difference is 51-25=26 deg C. Since the Junction-to-case (top) thermal resistance per the specification sheet is 44.2 deg C/W, it would mean that the dissipated power is only P=26/44.2=0.5W, which is clearly incorrect. Cf. also Fig. 15 in the specification sheet.

Any help with whether I am misinterpreting the specification sheet, making error in my calculation, or any other reason for the above would be appreciated.

Kindest regards,

M

This 1960s small-signal triode-pentode has the suppressor grid of the pentode connected to the heater rather than to the cathode. Could anyone shed some light on why this arrangement was used or identify other valves/tubes with similar connections (noting that the 9QP base is perhaps unique to the 6KT8)?

Snell type Ci crossover schematic.Does anybody one they could share?

Hi,
I’m planning to build a modified Flex-8 speaker from MTG. I have questions that I hope some of you could answer.

#1
Without changing the internal volume or box tuning, I would like to design the box in a more altec-ish fashion. That is: bass cabinet with front port, and "naked" horn on top.



Do you think it might dramatically alter the sound? — because of baffle diffraction, speakers alignment, port shape and placement etc…

#2
How critical is the choice of the horn? I like the Celestion H1SC-8050, but I feel a wider shape would both be more æsthetic and adapted to my objectives (I’d like the widest horizontal dispersion possible).
I’m thinking Dayton Audio H6512, Dayton Audio H812, BMS 2119, B&C ME45… Would those work with the LaVoce DF10.101LS?
I know that horns shapes and materials affect sound, but my question is how much? Does changing the horn necessarily calls for a dramatic redesign of the crossover?

—

In a nutshell, I guess I’m asking how much these small edits could ruin the sound, or not.
Note that I’m not a hifi-purist looking to the ‘perfect’ sound. My concern is avoiding to spend hours and hundreds on a project that is predictably going to sound bad.

Thanks everyone 🙂

PS: MTG, if you read this, thank you so much for your blog. It has been immensely helpful.

Can anybody please help me identify the pcb mount speaker jacks of the type used in every home theater receiver I have seen.

I am trying to get data sheets etc but I cannot for the life of me come up with the appropriate search terms.

I either get panel mount speaker jacks or pcb mount rca sockets.

I imagine this is an easy to find generic item given their ubiquity in big brand audio gear.

Hey guys, noob here. I'm not sure how to interpret these results. I've been trying to get WinISD to run on my Mac but I've been trying various forms of Wine for days and am starting to give up D:

I'm aware this driver has weak excursion but I wanna run it through the gauntlet before upgrading. Is it correct that that Max Power Input of my whole mechanical system is 40W? So I don't need an amp for more than 50W or so? I've seen recommended box designs from the manufacturer for more than 250W... and how should I adjust Nominal Power

I'd appreciate any input here

I purchased this table in 2010, and while it's served me well since, the time for a change has come. It works without a hitch. The main board has been recapped, the tonearm carriage servo motor belt replaced, and the carriage rails cleaned and re-lubed. Cosmetically, the table is in very nice shape, with just a few small marks here and there, including one on the front rosewood piece.

Some background on the 8002.

$550. Local pick-up in Northern NJ.

I'll include an MMC2 cartridge. I had it rebuilt--new suspension, sapphire cantilever and nude line contact diamond--however, the stylus met an unfortunate end, and the cart currently needs to be re-tipped.

I would like to know if someone can help me and tell me if it is possible to make a 3-way ripol.

SOLD
Creative Sound Solutions 1TD speaker kit with upgraded Crossover components. Thick air core inductors, high quality capacitors including Jantzen Superior Z Caps. All that is needed is cabinets, which can be made by yourself, or flat packs can be bought directly from CSS.

This kit sells currently on CSS for $550 with standard crossover. I would like to get $450 plus shipping, or local pickup 45431. Am also selling on eBay, if you're more comfortable with that, although my cost there is $580 plus shipping. Thank you 🙂


What's included:


2x CSS LDW7 Woofers

2x CSS LD22 Tweeters

All crossover components for one pair

Eggshell foam for internal damping

2x ports

2x binding post pairs

Hi Guys,

If I wanted to modify the secondaries of a surplus toroidal transformer.

Is it as simple as counting the turns ratio of the unloaded secondary voltage to figure out the volts per turn and then scaling that up and down accordingly?

I assume there is some additional complexity regarding the wire gauge and the pattern and or spacing of the winding but we will leave that aside for now.