I have the following for sale. Local pickup only. Augusta, GA 30809

$7,000 - Jamo R909 black gloss - Revelator 9700, Seas Hexadym, 2x 15" woofers (21" surface area) per speaker
$2,000 - Clearwave Symphonia speakers in cherry - Accuton Cell c25-6-158 tweeter & C90-6-724 midrange, Scanspeak Illuminator 7" woofer


Measurements:
Jamo R909 (now owned by Klipsch)
Revelator 9700 - Hificompass - https://hificompass.com/en/speakers/measurements/scan-speak/scanspeak-d2905970000
Seas hexadym midrange - VoiceCoil Review - https://audioxpress.com/article/test-bench-seas-w15ch001-5-25-excel-hexadym-motor-midwoofer
Brochure: https://assets.jamo.com/files/r-909-whitepaper.pdf

Clearwave Symphonia
Accuton Cell c25-6-158 - Hificompass - https://hificompass.com/en/speakers/measurements/accuton/accuton-c25-6-158-cell
Accuton Cell C90-6-724 - Hificompass - https://hificompass.com/en/speakers/measurements/accuton/accuton-c90-6-724
Scan-speak Illuminator 18wu-4747T00 VoiceCoil Review - https://www.scan-speak.dk/datasheet/reviews/18WU-4747T00-VoiceCoil_2010-4.pdf

The Scanspeak 9700 is one of the lowest THD tweeters there is. Hexadym midrange is excellent for open baffle due to magnet design and measures well.
Accuton Cell midrange is HiFicompass's favorite Accuton midrange, costs $742 each; the cell tweeters $542 each. The underhung illuminator aluminum woofer is tested in VoiceCoil to have 10mm xmax, 4mm beyond spec. The paper version has been reviewed by Erinsaudiocorner and is similar with less xmax.

*This has already been posted in another section, I've copied it here as well on the advice of a fellow member. Mods, please delete if you feel the other section is more appropriate

I have a valve PA amplifier which has been my possession for many years. It was my late grandfathers. I've never seen it working. It's complete but would obviously need a fairly comprehensive overhaul before it could be used. The valve line up is EL34, EL34, ECC81, 6BR7, 6BR7, ECC82. There are 2 EZ81 rectifiers also.
It's an strange old thing which has the option of running from a 12v battery. It has a wierd mains/battery socket on the front. I think it looks pretty cool and would love to use it as a guitar amp and build a little cab for it to sit on top of, finishing both the amp and speaker cab in a matching quilted leatherette similar to the beaten up stuff that's already on the amp casing.
Whatever happens, it stays as it looks now. It won't be cannibalised for parts!

The issue is that I can't find a schematic for it. I've looked many times over the years and come up with nothing.
Searching on Google just brings up old posts on vintage-radio, (one of which was made by myself), another gives some interesting background info on the company who made it. However there's no schematics posted anywhere.
If I had a diagram to follow I'd be able to make better sense of the circuit but as a relative beginner, it's beyond my capabilities to trace out the entire circuit.

So, I'm thinking of just starting from scratch and finding a suitable guitar amp schematic which uses the EL34's and rewire it that way.
I've no use for the 12v circuitry etc...

I'm thinking a good starting point would be to make sure the transformers work, these being the most expensive things to replace.

If anyone can suggest a guitar amp that could be make use of as many of the existing components as possible, let me know.

Any ideas on how to precede will also be welcomed!

https://medicalxpress.com/news/2023-09-neural-underpinnings-effects-presence.html



dave

Hi,

here some data to show magnitude of effects room has on bass response, and how much bass box alignment matters in comparison.

Short story: I've had some 15" woofers for many years and have been prototyping a speaker system with three way mains speaker equal amount of time. Currently on third bass box version for the mains, and I've been downsizing every time as I've always had to EQ the lows lows down to match up sensitivity of rest of the system. Also, I've felt there is coloration of sound from the bass box, which ought to reduce by better construct, smaller panels, modes inside higher up in frequency, minding about the port and so on. In general, as box gets smaller any issues get higher up in frequency, hopefully beyond pass band and out of harms way and should reduce any "box sound".

But that would compromise the bass, right, making box smaller than a simulator suggests? True if only looking anechoic response on the screen and forgetting the box will be in a room along with rest of the stereo playback system. And in this case, a 15" bass provides plenty enough for my home use, so there is extra SPL potential that can be sacrificed. Your system and context might differ, so please post if you have an example, perhaps even a counter example.

Anyway, my first box is already scrapped so approximating a bit. I remembered it was 150l but it was likely smaller as simulator suggests 113l for the driver automatically. Lets assume it was 113litre and try to remember the tuning. Second box was and still exists about 80l. Third box is sealed and only about 50l. Here are box simulator responses for the three, all using the same woofer:


Dramatic difference, right, the 50litre box response drops much higher than the other two and should have underwhelming bass. Also the 80litre box should shame on the 113litre, which should have much "better" bass, right, that's what the simulator automatically suggests at least.

Let's find out, here is measurement of one of the boxes. This is box that does sub woofer duty right now, and one of the three above. Mic was at listening spot, ungated sine sweep. Can you guess which one of the three is it? You can guess it reasoning with the text above, but the important bit is can you read the box alignment from this graph? The reflex boxes are tuned around 40Hz but here is crazy dip around 40Hz.


No, I cannot read the aligment. It's the 80l reflex box.
Here is the box simulator SPL graphs from all three above overlaid on the actual measurement, see correlation now? I cannot still 😀


The green line is the corresponding simulation. Huge 14db peak above simulated SPL at 33Hz and 11db dip at 39Hz with the room and positioning I happened to have this time. I'd say the response would be pretty much the same regardless which one of the tree enclosures it was, a 113litre reflex box or 50litre closed box. They would have some differences, but none would measure like the simulation.

ps. the measurement voltage was not calibrated so the amplitudes are matched roughly by eye.

Alright, here is the 50l closed boxes, main speakers Left and Right and both overlaid. The boxes are at different location in room being Left and Right main speakers, while the mic stays put.


On these graphs the measured responses show trend of the simulated response quite nicely, varying roughly +/-10db due to influence of the room. I have to use EQ to make sound better like with all of the boxes. These small boxes sound lean without EQ and the bigger reflex boxes sound boomy without EQ, and with all of them it's very hard to get system bass nice sounding, which I attribute to peaks and dips in the response but of course could be anything as I'm a hobbyist.

Anyway, to get some feel on magnitude of things: If the room influence was translated into amplifier power it would mean that if I fed 10W to the speaker, the dips would be equivalent of feeding 1W power (10db less) and peaks 100W (10db more), total effect of room is 100x amplifier power! Looking at the combined graph, around 47Hz the left channel has 16db more output than the right, that is 40x difference in amplifier power between Left and Right channels, due to room.

So, manipulating positioning of things is very important, while box alignment is less important, almost meaningless in comparison at least in this particular example.

Lesson in my particular case presented here: as the room already ruins the bass response and manipulating it to liking would require separate bass system and EQ, or at least EQ, I could further ruin the bass without any extra harm by sacrificing some of the extra bass output that box simulators originally suggested, just tweak the EQ. This allowed to make smaller box that's both easier and cheaper to build, easier to accommodate and position in room, has less audible issues on midrange and bass performance is pretty much still the same as before, dominated by the room! I had to use EQ on all of the boxes to make system response balanced.

Based on this experience I don't mind main speaker bass alignment too much currently, other than better make it so that midrange works as well as possible, basically to optimize everything else than the bass. I feel main speaker bass box alignment has very little to do with perceived bass quality, instead one should consider utilizing separate bass system that is specifically adjusted with the room to get the response you want with SPL capability you want, by what ever means suit you like using some gradient bass system, positioning, EQ, multisub, tearing down the room, what ever.

Many of you already know all this, but many of you don't, like I didn't when starting off spending hours in front of WinISD looking at wrong things. It was interesting to see the graphs today, so though to share. Have fun!🙂

Hi.

I have a KRK 10S 150w Sub speaker. When I power it the main fuse blows, I've gone through a few fuses fault finding but with no joy in finding a fault, Therese nothing obvious when I look inside the unit, blown caps etc. New whole parts (ie pwr supp) are thin on the ground as its pretty old, to replace the whole thing would be about £400 2nd hand.

In short I want to get a stand alone amp (150w), drill a whole in the sub cab and connect directly to the speaker from the amp bypassing all the electronics of the unit and just utilising the cab and speaker, feeding the amp from the SUB op of my DtoA converter which in turn is fed from the Dolby Atmos software (sub op).


Can anyone recommend a "cost effective" preferably class D, balanced input amp that could do this. The speaker is 8ohm, 10 inch. Or tell me why this is a bad idea!?

Thanks!

Hi,

About 3 years ago I built an amp based on a Champ using parts from an old unidentified amp. It has recently developed a constant hum, regardless of the volume position. Its not really loud, but since it used to be really quiet, I want to figure out the reason. When building it, I used new good quality capacitors, but some resistors I did recycle, as well as the tubes that came with the amp. Before I open it up, I'd like to ask if there are points I should check with a volt meter to help find the reason for the noise. I've attached the schematic. Some resistor values have changed, and noted, but the updated schematics are inside the amp.

Thanks

Hi all!
I stumbled on to this board looking for speaker specs (salvaged speakers from TVs, cheaper speaker cabs, computer speakers, etc) AND I am going to recreate one of my favorite sets ever.
At some point in the early 80's I made the double chamber reflex speakers from Weem's book "Building Speaker Enclosures" and yes, I was at R/S at least once a week going back to the early 70's!

Right now I have a pair of JBL 166's that I re-foamed years ago and a pair of Infinity 120's (also re-foamed). And I'm looking at a pair of Mitsubishi SS 152's for $200 ea in fairly good shape.

I want to be able to get accurate numbers so I can make better/funky, weird enclosures for some of these "no-name" drivers (because, why not?) and so far it looks like the the Dayton Audio DATS (thoughts, suggestions?)

Ciao!

Have for sale one each of -

QSC GX7 power amplifier new in box, never opened. Purchased from Parts Express 2 yrs ago. $600 shipped to lower 48 US states only

DBX Driverack Venu 360 speaker management processor, new in box only opened for testing. $700 shipped to lower 48 US states only

Please PM me if interested.

All of the Black Gates are new.

Purchased from Parts Connexion many years ago.

Price USD
10 x BG NX 47uF 6.3v 30ea ,new price $25.00ea
6 x BG N 33uF 16v 50ea ,new price $45.00ea
(4 x BG N 47uF 50v 50ea. Sold)
2 x BG N 4.7uF 50v 50ea , new price $45.00ea
3 x. BG STD 330uF 16v 35ea , new price $30.00ea

Plus shipping

Can anyone help me understand the capacitor values on this circuit? They're given in P and Kp. Some of them don't have K or KP, just a number. I was thinking the P denoted Pico farads, but it still doesn't really make sense to me. Say '10kp', is that saying 10,000 Pico farads?

Thanks 👍

Hi - thanks for having me here. I'm Tim from Sheffield, UK. I'm a sound engineer (Studio and TV outside broadcast) by trade but compose semi pro in my spare time. I've just put together my Dolby Atmos 7.1.4 room at home, mostly for experimentation rather than as a commercial venture. I'm looking for advice with simple electronics problem solving in the studio environment, not building. And I will now reading some of the very interesting posts on here!!

Thanks!!

hello,
a newbie here, first time XO planning. i used the 3 way crossover from the library and tweaked it. i have a few questions hope i can understand the answers 🙂

drivers
T - Dayton Audio AMT Mini-8 Air Motion Transformer Tweeter 8 Ohm
M- Dayton Audio PS95-8 3-12 Point Source Full Range Driver 8 Ohm
S- Dayton Audio LW150-4 6 Low Profile Woofer 4 Ohms

1, can thes XO can be simpler to build? less parts or smaller parts
2. what do you think about the values of the components and the overall graph?
3, can you guess the cost of the parts? rufly

For disposal: I have an Avondale Audio SE200 power amplifier which is surplus two requirement as I have now upgraded to the SE400's.

The transformer is an Audio Grade 540va from Tiger Toriods
The SE200 amp boards have been populated with exotic component variants (audiophile types) in appropriate locations.
The power supply is the latest offering from Avondale the NCM3 with 60,000uF capacitance per rail totaling 120,000uF in total for the amp, and incorporating Schottky rectification (MBR10200)
The power supply also has its own soft start onboard!!
The case is from Modushop 2U 400mm deep, the facial is unmarked new.

Audition welcome by arrangement (Hampshire UK)

£1500

Free hipping to UK only
.

Looking for good sites to purchase hi resolution music.
Any recommendations welcomed

Hello. I have some Fostex FE208EZ drivers for sale

https://www.madisoundspeakerstore.com/approx-8-fullrange/fostex-fe208ez-8-full-range-sigma-series/

The total usage between them is less than 2 hours

I have 3

2 for $350 plus shipping. Make an offer on the third/a single

Let's say I've built a power supply with a transformer that converts 120v to 25v, and then a bridge rectifier, and some filter capacitors. Now I've got 25VDC to connect to my equipment. What determines the number of amps my equipment can draw? Is it the total capacitance of the filter caps? Then I guess there's the transformer, and then the wall.

To put it another way: If I double the capacitance of my power supply, did I just double it's maximum amperage?

I have decent studio DAC from Antelope Audio model Zodiac Gold. I use it mainly to play files from HD since I have a decent library of redbook , High rez and DCD files .For a change of presentation I took it's SPDiF output to feed an older dac which has no USB input effectively using Zodiac as a USB SPDiF. I have problem with noise between tracks . Any idea how to fix it ?
These are specs on Zodiac digital outputs
1x AES/EBU De-Jittered, re-clocked Digital Output. 110 Ω. 2x S/PDIF De-Jittered, re-clocked Digital Outputs. 75 Ω.
I will add that input of an older Dac either re-clocks the signal or uses custom jitter reduction process (those are the options to chose)

I plan to build a classic EL34 UL PP amp. One of the big questions is which output transformer to use. I know this has been asked before but the most recent thread I can find is 4 years old and a lot can happen in the world of transformers in that time. I am in the UK so European suppliers would be preference but not essential. I am aware of the Sowter offering but that is a little expensive for my tastes. I am looking for something of reasonable quality that is not too expensive, i.e. good value for money.

Recommendatiion?


Cheers

Ian

After a recent thread about load lines for push-pull tube amps, I decided to try matching triode-wired GU-50s to a couple of OPTs I have lying around. One has 8k ohm (plate-to-plate) primary, the other about 5k ohms. Check my work? Did I do this right?



I chose Vp-k of 380V and Ip of about 80mA (Vg1 of -60V) because that's a reachable set of operating points with power transformers I have available.

What would be the disadvantages to using an OPT with 5k pri? Are there significant advantages to using an OPT with 8k pri?

I'm working on the layout/parts ordering for my build which is slowly coming together. So far, I had planned on positioning the Power Trans and OPTs conventionally at the top/back of the chassis - i.e. Power trans in one corner, rotated 90 degrees to the OPTs. positioned side by side at the other side. My question concerns positioning the choke and supp cap.

To save size and space on the main chassis, I could build a small frame inside the enclosure, using V slot 2020 aluminum (grounded of course) and mount the choke on it below the Power trans and the supp cap laying horizontally on the frame under the OPTs.

Does anyone foresee a problem with that approach?

Hello,

I ordered the wrong part for my setup, so I'm selling a brand-new IsolatorPi II for 40€+Shipping. I'm also looking for a FIFOPi Q7.

Regards,
Denes

These were kept in stock by me only to be used in excellent equipment. I decided to sell them as the DIY frequency is not high enough to justify keeping stock. These were all bought from an official distributor. I never noticed deterioration but of course they need the hours for "breaking in". These were bought when the announcement came that production would stop.

These values are in stock, I checked prices but they vary a lot. I don't recall what I paid for them except that is was a very expensive affair. I do recall thinking that I bought caps with a combined value of a nice second hand car 🙂

BG NX Hi-Q 47 µF/6.3V 25 Euro/piece
BG NX Hi-Q 22 µF/6.3V 17.50 Euro/piece
BG NX Hi-Q 0.47 µF/50V 12 Euro/piece
BG NX Hi-Q 0.1 µF/50V 10 Euro/piece

I have many other values and series and will post these later on.

I have a 1000/1 on the bench which shorted a pair of output FETs, but replacing them didn’t solve the problem. When it turns on, it makes a shrieking sound...

After some poking around with the scope I realized that all the output gates have drive, but the on time isn’t balanced between the high and low side like I would expect. The PWM is unbalanced all the way back to the comparator. Probing pin 5 of U511 shows the normal sawtooth coming from the 555 timer as expected, and pin 4 is 1.7v. Sure seems like pin 4 should be higher, like maybe around 2.5v?

Can anyone verify what pin 4 should be, and if that’s what’s wrong, what sets the DC on that pin? Offset pot had no effect.

Here is a tapped horn design intended for pro sound reinforcement type applications, or any just plain old, really loud music apps that I started working on last July and finally finished the design back at the beginning of March. I worked on this in tandem with the Gjallerhorn. I decided to have the Gjallerhorn built first as it was a larger, more complicated, more expensive and risky design. Since it turned out so well I am feeling rather confident about this one. 😎 My goals with this design were true 30hz extension with solid useable output to the 25hz range. This is quite a bit lower than the majority of pro bass bins will really reach to despite their ratings. The increasing popularity of down tuned 5 and 6 string bass guitars, bass drops and the prevalance of DnB and Dubstep genres have started to ask for more power than ever from subs in the 25-35hz range. Along with this extension I wanted it to still be able to get quite loud and to retain decent sensitivity. I also decided to use an enclosure form of no larger than 36x36x24" which is large but not out of the ordinary for pro bass bins and comparable in total volume with many double 18" vented subs. A larger 45x45 type of cabinet like the Gjallerhorn or Labsub would've given better efficiency and higher output but these types of cabs are larger and heavier than I want to lug around very often. A pair of these should do most bars or small venues with no problem and 4 should do a good job in a mid sized venue. 2 will fit in the cargo hold of most medium sized suv's.

I already own a pair of B&C 21sw152-4 drivers and Danley has already used them in a couple of tapped horns so it was a no brainer to design around them.

Fast forwarding through about 9 months of design work and revisions here is what the final design will be. I will contract he same cabinet shop that built the Gjallerhorn cabs to do these as well. Unfortunately with everything else going on I don't have the time to build cabs this complicated myself anymore🙁. Besides I could never deliver the build quality that the professionals can.

BTW Thanks to Soho54 for being my sanity checker on this cab design.

Here is the HornResponse and Akabak input data for simulating the cab. This one was also designed in Akabak working backwards from the cabinet size and best fold that would fit in the cab and achieve the right low corner instead of the other way around. I have found this works much easier for me than coming up with a pretty simulation and trying to fold and cram it into a workable cabinet while maintaining the parameters. Once again I use Akabak since there were so many folds, different expansion rates and corners involved. Amazingly the much simpler HR simulation that approximates the final Akabak one is very close. The differences are there but quite small. Not worth worrying about for most people unless you are a stickler like me who is worried about accuracy to the nth degree. Anyway here are the inputs.



NOTE: If you wish to model 18" drivers in this cabinet you should change the value of VTC to 4000 and the ATC value to 1465

HR





Akabak script
|COMMENT: OTHORN B&C 21SW152-4 30hz TH 36"x36"x24" revised 030411 completion(Driver restricts horn by approximately 517cm2 at S32)



|========================================================================================================



|REQUIRED AKABAK SETTINGS:



|File > Preferences > Physical system constants:



|Sound velocity c = 344m/s

|Medium density rho = 1.205kg/m3



|Sum > Acoustic power:



|Frequency range = 10Hz to 20kHz

|Points = 533

|Input voltage = 1.86V rms

|Integration = 2Pi-sr

|Integration steps = 1 degree ... 1 degree

|Integration method = Cross



|========================================================================================================



Def_Const |

{

|Length, area and volume values converted to metres, square metres and cubic metres:



S1 = 20.397216e-4; |Horn segment 1 throat area (sq cm)
S2 = 400.79072e-4; |Horn segment 1 mouth area and horn segment 2 throat area (sq cm)
S3 = 480.93721e-4; |Horn segment 2 mouth area and horn segment 3 throat area (sq cm)
S4 = 490.40735e-4; |Horn segment 3 mouth area and horn segment 4 throat area (sq cm)
S5 = 499.87748e-4; |Horn segment 4 mouth area and horn segment 5 throat area (sq cm)
S6 = 503.41786e-4; |Horn segment 5 mouth area and horn segment 6 throat area (sq cm)
S7 = 752.67183e-4; |Horn segment 6 mouth area and horn segment 7 throat area (sq cm)
S8 = 525.374e-4; |Horn segment 7 mouth area and horn segment 8 throat area (sq cm)
S9 = 672.07369e-4; |Horn segment 8 mouth area and horn segment 9 throat area (sq cm)
S10 = 1003.4701e-4; |Horn segment 9 mouth area and horn segment 10 throat area (sq cm)
S11 = 706.47214e-4; |Horn segment 10 mouth area and horn segment 11 throat area (sq cm)
S12 = 710.68271e-4; |Horn segment 11 mouth area and horn segment 12 throat area (sq cm)
S13 = 1011.4833e-4; |Horn segment 12 mouth area and horn segment 13 throat area (sq cm)
S14 = 744.03216e-4; |Horn segment 13 mouth area and horn segment 14 throat area (sq cm)
S15 = 827.70445e-4; |Horn segment 14 mouth area and horn segment 15 throat area (sq cm)
S16 = 1148.9606e-4; |Horn segment 15 mouth area and horn segment 16 throat area (sq cm)
S17 = 850.19967e-4; |Horn segment 16 mouth area and horn segment 17 throat area (sq cm)
S18 = 852.58905e-4; |Horn segment 17 mouth area and horn segment 18 throat area (sq cm)
S19 = 1222.0554e-4; |Horn segment 18 mouth area and horn segment 19 throat area (sq cm)
S20 = 876.8326e-4; |Horn segment 19 mouth area and horn segment 20 throat area (sq cm)
S21 = 434.06586e-4; |Horn segment 20 mouth area and horn segment 21a throat area (sq cm)
S22 = 572.31875e-4; |Horn segment 21a mouth area and horn segment 22a throat area (sq cm)|
S23 = 1185.3696e-4; |Horn segment 22a mouth area and horn segment 23 throat area (sq cm)
S24 = 1724.8322e-4; |Horn segment 23 mouth area and horn segment 24 throat area (sq cm)
S25 = 1255.2883e-4; |Horn segment 24 mouth area and horn segment 25 throat area (sq cm)
S26 = 619.44195e-4; |Horn segment 25 mouth area and horn segment 26a throat area (sq cm)|
S27 = 680.54455e-4; |Horn segment 26a mouth area and horn segment 27a throat area (sq cm)|
S28 = 1400.7642e-4; |Horn segment 27a mouth area and horn segment 28 throat area (sq cm)
S29 = 2279.1994e-4; |Horn segment 28 mouth area and horn segment 29 throat area (sq cm)
S30 = 1799.9231e-4; |Horn segment 29 mouth area and horn segment 30 throat area (sq cm)
S31 = 1805.1536e-4; |Horn segment 30 mouth area and horn segment 31 throat area (sq cm)
S32 = 1411.3236e-4; |Horn segment 31 mouth area and horn segment 32 throat area (sq cm)/(1411.3236cm restricted by driver (estimated),1928.3236cm ignoring driver in path)
S33 = 2043.1017e-4; |Horn segment 32 mouth area and horn segment 33 throat area (sq cm)
S34 = 2057.0009e-4; |Horn segment 33 mouth area and horn segment 34 throat area (sq cm)
S35 = 2260.638e-4; |Horn segment 34 mouth area (sq cm)

L12 = 27.504644e-2; |Horn segment 1 axial length (cm)
L23 = 27.258518e-2; |Horn segment 2 axial length (cm)
L34 = 3.070098e-2; |Horn segment 3 axial length (cm)
L45 = 3.355594e-2; |Horn segment 4 axial length (cm)
L56 = 1.203198e-2; |Horn segment 5 axial length (cm)
L67 = 3.625088e-2; |Horn segment 6 axial length (cm)
L78 = 3.781298e-2; |Horn segment 7 axial length (cm)
L89 = 41.853612e-2; |Horn segment 8 axial length (cm)
L910 = 4.81838e-2; |Horn segment 9 axial length (cm)
L1011 = 5.029708e-2; |Horn segment 10 axial length (cm)
L1112 = 1.20142e-2; |Horn segment 11 axial length (cm)
L1213 = 4.740656e-2; |Horn segment 12 axial length (cm)
L1314 = 4.877562e-2; |Horn segment 13 axial length (cm)
L1415 = 37.930582e-2; |Horn segment 14 axial length (cm)
L1516 = 5.453888e-2; |Horn segment 15 axial length (cm)
L1617 = 5.582412e-2; |Horn segment 16 axial length (cm)
L1718 = 1.20269e-2; |Horn segment 17 axial length (cm)
L1819 = 5.869432e-2; |Horn segment 18 axial length (cm)
L1920 = 6.282436e-2; |Horn segment 19 axial length (cm)
L2021 = 1.371346e-2; |Horn segment 20 axial length (cm)
L2122 = 46.972982e-2; |Horn segment 21a axial length (cm)
L2223 = 2.97434e-2; |Horn segment 22 axial length (cm)
L2324 = 7.91972e-2; |Horn segment 23 axial length (cm)
L2425 = 8.488172e-2; |Horn segment 24 axial length (cm)
L2526 = 2.246376e-2; |Horn segment 25 axial length (cm)
L2627 = 30.794452e-2; |Horn segment 26a axial length (cm)
L2728 = 2.872232e-2; |Horn segment 27 axial length (cm)
L2829 = 11.00836e-2; |Horn segment 28 axial length (cm)
L2930 = 10.296144e-2; |Horn segment 29 axial length (cm)
L3031 = 1.199134e-2; |Horn segment 30 axial length (cm)
L3132 = 27.93238e-2; |Horn segment 31 axial length (cm)
L3233 = 26.647902e-2; |Horn segment 32 axial length (cm)
L3334 = 3.189478e-2; |Horn segment 33 axial length (cm)
L3435 = 6.672834e-2; |Horn segment 34 axial length (cm)

Vtc = 7400e-6; |Throat chamber volume (cc)(Estimated)

Atc = 2026.00e-4; |Throat chamber cross-sectional area (sq cm) (Estimated)



|Parameter Conversions:



Sd = 1680.00e-4; |Diaphragm area (sq cm)



Ltc = Vtc / Atc;

}

|========================================================================================================



|Network node numbers for this tapped horn system:



| 0-Voltage-1

| |

| -Chamber-5-Driver---

| | |

|8-Segment-9-Segment-10-Segment-11-Segment-12-Segment-13-Segment-14-Segment-15-Segment-16-Segment-17-Segment-18-Segment-19-Segment-20-Segment-21-Segment-22-Segment-23-Segment-24-Segment-25-Segment-26-Segment-27-Segment-28-Segment-29-Segment-30-Segment-31-Segment-32-Segment-33-Segment-34-Segment-35-Segment-36-Segment-37-Segment-38-Segment-39-Segment-40-Segment-41-Segment-42-Radiator



|========================================================================================================



Def_Driver 'Driver'



Sd=1680.00cm2

Bl=32.57Tm

Cms=5.35E-05m/N

Rms=13.28Ns/m

fs=32.0001Hz |Mmd = 422.82g not recognised by AkAbak, fs calculated and used instead

Le=1.50mH

Re=3.40ohm

ExpoLe=1



System 'System'



Driver Def='Driver''Driver'

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Radiator 'Horn mouth'

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I'm getting deaf with age and work related issues. Worse it becomes more I like mainstream electronics and speakers most of you guys love so much but can't afford 🙂
I found on the curb a pair of MBL 311E piano finish speakers which I quite like even though they sport 17cm Davis kevlar midwoofer , material I used to hate. They do well in the "mimicking bigger speakers " department mainly thanks to severe shelving the efficiency to mere 84db/4 Ohm . Manufacturer quotes 44Hz . I do not want to touch the crossover in the speakers I just may introduce 6db high pass filter . I would like to add some true bass , mid bass from at least 10" woofer . Separate enclosure bi amped . I'd either replace stands with the box or build two tower boxes standing next to the speakers in unfortunately narrow but long space (10 ft wide). Is it something worth pursuing or I'd be wasting my time? I dismiss subwoofers. I have those in the corners of the room. Sealed , tight but it's not gelling with mains in the proper way. I need a driver in direct line with kevlar midbass.
https://stereonomono.blogspot.com/2018/12/mbl-311e-speakers.html

We have a new forum category to discuss electronic design.

This allows for a logical space where concepts that are unrelated to a specific piece of hardware can be discussed, such as the pros or cons of wide of narrow bandwidth in electronics or the intracies of feedback.

https://www.diyaudio.com/community/forums/electronic-design.200/

I think Jan will get the ball rolling shortly... 🙂

I like challenges … so I decided to give it a try.

Part One of many:
Credits go to: BUG AMPS, bugamps.com, A Big Thank You for the support I received so far!!!

The concept, a schematic tells it all…

The PSU, another nice schematic…

To be continued with Part Two: Some knowledge.

Hello! I have an older DSP that doesn't have a digital input.

I have the schematic for it. The A/D converter is a PCM1802. Fairly certain I've seen digital input boards for a reasonable price. Would it be as simple as disabling/removing the current A/D and connecting power to the converter and connecting the data/LRCK/BCK/MCK and selecting the interface mode?

If we believe Morgan Jones when he writes in "Valve Amplifiers" of the 5-20:

"The input stage is an EF86 pentode, which is responsible for the high gain but poor noise performance...."

"The cathode coupled phase splitter is combined with the driver with the driver circuit using an ECC83...... The output stage has an input capacitance of ~30pF, and combined with the 53k ohm output resistance of the driver stage, this gives a cut-off at ~100kHz, which is quite poor."

"....the driver stage has only 10dB of overload capacity. When the output stage gain begins to fall, for whatever reason - cathode feedback, input capacitance loading the driver, or primary inductance in the output transformer - the global feedback loop will try to correct this by suppling greater drive to the output stage, and the 10dB margin will be quickly eroded, raising distortion."

Jones goes on to discuss the output tube's individual biasing resistors and their bypass capacitors, "The capacitor is a short circuit to AC, and so prevents feedback, but its reactance rises at very low frequencies, so it is no longer a a short circuit, and allows feedback. Because the output stage is load matched, this feedback causes an immediate rise in distortion and reduction of power output due to the mismatch."

There are other points as well, I've just chosen a few.

Isn't it time we moved on from the Mullard 5-20?


Cheers, Steve

Hey guys I got an idea instead of buying and selling commercial speakers, thinking about building or buy a kit or a project with a 2 way horn speaker, with a 12 inch and a compression driver,my goal is clean and low distortion,and a good directivity horn with a proper horizontal distortion,(wider is my preference as I think they sound the best in a home environment, here in Italy we have faital drivers , and I think they could be good candidates, and I already have 2 18n862 BMS subwoofer that could be crossed at like 100hz Soo the 2 way speaker could be crossed little higher, do you have any opinion about this project? Thanks!

I was going through the closet, looking at what's sitting there on the shelf. It seems I squirreled away the iron from an old Dyna ST35 amplifier. (Its PCBs burned up back in the days before JLPCB made it so cheap 'n easy to have your own made.) I was recently given a nice aluminum chassis that's pre-drilled for a quartet of 9-pin output tubes and a couple of 9-pin driver tubes, with room for transformers, etc. Obviously, this has to be a project.

The speakers I want to use are all 4 ohms. I have a pair of Snell E/III that I like, and are supposed to have 91dB sensitivity (but at 1W? 2.83V? I don't know).

The Z565 OPTs have 8 and 16 ohm secondary taps. I think their primary impedance is 8k plate-plate.

What would happen if I used 6P43P (EL86) tubes instead of the EL84 (6P14P) tubes the OPT was designed for?

• Running the 8k:8 rated OPT into a 4 ohm load on secondary would make it 4k:4, would it not?
• 6P43P has half the rp of EL84, so should be happy into a 4k p-p primary load.
• Z565 is supposed to present 100H primary inductance. Does that change if the OPT secondary is underloaded? Or is the primary L relatively constant?

Thanks for any help with this.

Hi I have a xtant x604 whit no power I found the T2 open is anyone can tell me where I can get this part o if somebody haved can I buy it thanks appreciate

Hi all, I just joined and I'm building my first "real" hifi/ht system but feeling a bit lost (lots of variety!).

For the past months I ended up spending probably too much time researching, reading and watching YouTube videos about various speakers. I also went to a couple hardware stores to figure out what I value in a speaker the most.

Anyways, since I'm doing a HT and wanted to have the same speaker all around, I thought of going DIY, but since it's my first DIY build I wanted to go the kit route. The problem is, all the time I spent researching was mostly about kits and speakers based in the US. And when it comes to EU, the websites are all barebones (as in a nightmare to navigate and find straightforward info) and even here it's a bit hard to find information or similar posts to what I wanted. I decided to just write this and see if some of you could help or give me a general direction to follow.

The room I'm putting these in is quite small 5x5 meters. It's a living room/home theater hybrid so that's both music and home theater, they are going to do double duty, I already did some room treatment for the projector, so I can do the same for the acoustics, that's not an issue. That being said there's a couple shelves on the sides. We will probably move in the next couple of years for a bigger space tho, so I really wanted something that I wouldn't have to ditch in a slightly bigger room.

After spending hours with multiple speakers in store, I tried most of the recommended brands. There was a single speaker I fell in love with, and that was the q acoustics concept 50. Which I was going to purchase but then I started making the math and with concept 30 surrounds it would add up. Plus since my center will stay behind the screen I would really prefer to have the LCR to be all the same and that would mean I'd have to buy an extra pair since they aren't selling singles. If I had to describe what I liked, it was the detail and soundstage compared to the others, so I guess I fall more on the analytical side of things. I also tried some Arendals, and I loved those.

Worth noting, these will be connected to probably a Marantz Cinema 50 for starters. I will add some dedicated amps as I go.
I also don't care much about the deep low end, as I'd prefer to have a dedicated sub or two for that job.

So I guess my question is, is there a DIY speaker or parts that would give me a similar sound signature? I apologize for not being more throughout as I'm a bit of a newbie when it comes to speakers. I spent my entire life just using headphones (Audeze LCDS).

Thank you in advance!
EDIT: Can't believe I forgot, besides movie duty. The music we most listen to is Indie, some Metal, a bit of Pop with a high emphasis on vocals and the occasional EDM.

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Made of 16kg stainless steel.
The rotation is very smooth!
ebay link：https://www.ebay.com/itm/204355757660
ebay link（DIY KIT）：https://www.ebay.com/itm/204371770204

Ok is the Tesla audio amp too strong to be able to use with the dual alpine type r10's ..if I start gain from zero can I work my way up to match the rms output of the amp to match the rms of the subs? I'm new to car audio so need some help or pointers ..don't want to mess nothing up

My next project is a Electronic Switch aka Dual Trace for a Oscilloscope.

Here my schematic

I have a guitar amp in which it seems to have a faulty 2N5638 (obsolete) used for channel switching; there doesn't appear to be a suitable replacement locally.
I have a 2N7000 available, to only relevant difference seems to be that Rds on for the 2N7000 is ~ 1.2 ohms, the 2n5638 is ~ 30 ohms.
Should I give it a go?

Hi, Selling my Hypex FA501, slightly used, everything works perfectly.
Asking 300$ shipped within U.S.

Comes with what's in the pics.

PM if interested, Thank you!

Hello. Having done some utility apps for using my Keithley 2015 to measure my amps (https://github.com/andmarti1424/free_keithley), I just started this python project yesterday:






Its hosted on github as well: https://github.com/andmarti1424/loadline_plotter and its GPLv3.

I really like other similar loadline plotter like Merlin's Excel o VTADIY one.

But the problem with the later is that is not free and the loadlines data is not downloadable.
I really like to have hover over the plot to see the Va and Ia values.
And in VTADIY you cannot change maxY value so graphs sometimes shown too narrow.

The app current status is basic funcionality. It lacks validations, more useful data to show.
Remember its just a few hours of work.
Hope someone find it useful and if so, can help with PR...
Thanks.

Hello, I am currently wanting to set up a high fidelity (Hi-Fi) speaker company, but I don't have much knowledge about this market.

I already have knowledge about the materials I need to make the speaker cabinets and drivers.

So my question is: I need knowledge about the audiophile market.

Leave your advices.

Got an Smps with +12, -12, +5
Adjusted feedback resistors to get required by circuit +14V and +6V , -12V is generated by Lm7919 I measured unloaded input voltage at 16.8V
Space is tight ( those Smps are packed) So I'm looking for a fix. LM377 ?

I have a pristine QA401 Audio Analyzer available for sale.

I purchased it in a moment of despair when I thought I had broken my RTX6001, but fortunately, that was not the case in the end. I have only briefly tested the QA401 and never used it for anything serious, so it's as good as new. I bought it directly from QA in May 2020.

Please send me a private message with reasonable offers. We all know the value of this analyzer, so I will ignore offers below a certain threshold.

Additionally, I have a QA350 24-bit µV DC meter that I can bundle with the QA401. It's in an equally mint condition, as I never really understood what I needed it for 🙂

Cheers, Nic

The QA401 is sold

I'm trying to model maximum excursion for several drivers in a spreadsheet.

I have Max SPL per frequency as a function of Sd and Xmax. Max SPL obviously increases as frequency increases, leading to power / thermal handling limits - credit to a Jeff Bagby post:

SPL= 20 * log(10) (1.18 / 0.00002 * Sd * Xmax / SQRT(2) * 2 * PI * F^2)

Where Sd is in Meters^2
Xmax is in Meters one-way linear travel
And F is the frequency you want to solve for.

What I now want is the power limited formula equivalent (such that I can "cap" driver output above the point where Xmax would demand more power than the voice coil can handle in heat).

I have a power formula that uses driver Sd, Mms, BL and Re, but it seems to be about ~6dB out when calculating max SPL given max continuous driver power.

Can someone please post a formula or links to good references?

I tried to reverse engineer Linkwitz' closed box spreadsheet, but failed (maybe too tired). Linkwitz' model is better in the sense it caters for per frequency variable impedance, but I'm more concerned at the top end, not necessarily driver Fs or cabinet loading impedance changes.

Thanks!

A very nice broadcast tonearm by Denon specifically made to match the 103, clearly can be used with other cartridges as well.

Tonearm is in great conditions, rewired with silver cables, original head shell included but it needs one wire to be soldered (I preferred a modern head shell) and its original tonearm rest. Bearings are perfect, the tonearm was restored a few years ago.

And a direct drive motor with platter and rotary switches. It is a truly excellent motor. I just dismantled my proto turntable as I did not use it any more for years now

Tonearm 500€ or best offer
Motor and platter 100€ or best offer

Plus shipping costs from Italy

So I was planning on posting a whole set of - how I built my SE II and got all lazy but thought folks might find this useful.

I had trouble with Hammond 276 and 376X power transformers running REALLY hot so ended up going to a B373EX which is HUGE, but runs really cool. Used Edcors for outputs and mil-spec Vishay-Dale resistors (Mouser) or matched ones from Sonicraft.

All of the resistors are mounted on the top and caps on bottom. Board is mounted with 1/2" long standoffs to give clearance for the resistors and put the tube sockets about flush. All the board mount and transformer mount screws are 10-32 button head screws.

Super oversized heat sinks on the mosfets and power IC which resulted in this chassis arrangement with digital current meters for bias monitoring.

So what you get are some pictures but also PDF's that if you print full size will give you the hole layouts for everything. I tried to make notes on the PDF's but if you have questions, post them.

The transformer covers are from Ebay and work great. The small handles over the switch and front and back are there to protect connectors and frankly, aesthetics.

I used Greenlee chassis punches for the tube and switch holes as well as a bunch of vent holes in bottom cover.

The front RCA inputs are probably not ideal visually but keeps cable runs to absolute minimum.

I have large motor run cap set in the underside of chassis in a 3D printed clamp.

There are four extra holes in the top to expose the four adjustable pots and I cover them with little plastic plugs.

The whole thing is not small but its been running fantastic for well over a year now. AND SOUNDS AMAZING! Just wanted to get this out there for folks that might be interested. I will post a more comprehensive build over time. Biggest thing is I could not have built this without George and this community so just trying to give back!

The QA401 is now available and it has differential inputs and complete isolation from the host PC. Starting around here http://www.diyaudio.com/forums/equipment-tools/231401-quantasylum-qa400-186.html#post4657822 is discussion of the QA401 and some measurements. With the new version my efforts on a balanced out and differential in become less important but they still may help someone.

Several of us have been playing with these for a few months now. They are an inexpensive "sound card" USB capture device that has been optimized for audio measurement. More here: QA400 Audio Analyzer

The performance is quite good. More than adequate for any normal audio measurement need and the software works well, avoiding the usual problems with the Windows sound engines. It provides many good measurements as is and hopefully will get extended by others for specific tasks.

The one problem is that the I/O is single ended and limited to around 1V. This is fine for mobile audio stuff like iPods but not enough to work well with more conventional audio with 2V+ levels and amps good for much more.

In my prodigious free time (as in none) I worked out a design for an interface card to match the QA400 to real world audio devices. Its similar to Pete Millet's interface Soundcard Interface but not as refined or pretty. It also is two channel and doesn't have the metering, since the QA400 is quite accurate.

For the I/O I realized that making interface cables with appropriate connectors would resolve several issues. I have something like 5 pounds of adapters to go from anything to anything, however most end up as part of a link from one connection type to another. Usually for me its a dual BNC to Banana adapters to single BNC to dual banana to clip leads. Pretty dumb. My idea (borrowed from the Praxis interface PRAXIS INFORMATION ) is to make cables that have the appropriate adapter as part of the cable. The I/O is 3.5MM stereo connectors. This would be a stereo 3.5mm connector used as a differential interface terminated into an RCA for line level or two bananas for spoealer level, or XLR for balanced interfaces. Then the cable can have attenuators built into it eliminating the need for overload protection required for a dual banana type input.

I decided to steal power from the USB interface and make it a pass through. I'm using a DC-DC converter to get enough voltage to get 10V RMS out. I won't know until its built if this worked so easily.

The IC's will all be socketed on mine so they are easy to replace when they get fried.

I got my assistant Tim to do most of the heavy lifting on the layout. We have checked it and have sent it out for fab. We should have PCB's and parts in a week to build and test the design.

I am attaching the schematic and layout, all in Expresspcb ExpressPCB - Free PCB layout software - Low cost circuit boards - Top quality PCB manufacturing since I feel its very appropriate to this project. Please feel free to point out the dumb mistakes I made and improve it. The software is free from them.

PLEASE DON'T ORDER ANYTHING UNTIL I KNOW IT WORKS! I will post a revised version after I have made the first ones work.

I have two subwoofers for stereo subwoofers setup. Each subwoofer is placed next to each left and right main speaker. Since the electronic crossover, a/d/s/ 642ix, has fixed frequency module. It requires to change the module to alter crossover frequency. The currently available modules are 65Hz @ 24dB/octave and 170Hz @ 24dB/octave. And the electronic crossover allows to select either mono or stereo subwoofer operation. The manual suggests to set the operation to stereo mode only when the crossover is set above 100Hz. I need advice which setting I should use. Note that this is two subwoofers system, not usual single subwoofer setup. Please vote the poll and reply the opinion on comments.

I've been thinking of building a Sony V-FET amplifier using two paralleled pairs of 2SK82/J28 as described by Papa Nelson in the '40th Anniversary Sony VFET Amplifier' article and at CES in 2014. Did anyone ever make PCBs for this amp? I know I'm about a decade late to this game... Thanks

Hi, I'm in a hunt for a decent stereo amp available to buy as a device or a DIY kit with a budget around 150EUR.
I've spent last 2 days reading the forum and watching reviews. I didn't found a particular highly rated model, thus decided to ask. The usual suspects are the TPA3255 (Aiyima, BRZ) or MA12070 (Topping PA3S) packages but I can't pick a winner. Also "some say" they can't come close to something like Cambridge Audio AXA25.

My needs are very simple - low noise amp, stereo input from a PC and 2x30W output for a 8ohm Mark Audio Alpair 10p drivers.

I have access to soldering stations at my work so I will consider a model which can benefit from better capacitors or some other easy upgrade.
One thing I will greatly appreciate would be a USB audio interface so I could eliminate the need for a quality sound card.

Any recommendations?

I printed a set of adapters to fit my Visaton WG148 waveguides thinking I had the correct STL file, but it looks like its for another WG.

Its been a while since I downloaded the file and I dont remember.

Dimensions are 4.5" OD and the opening tapers to 50mm. I'm not sure if its intended for the Monacor WG300?

Can someone tell me which file is the correct one for adapting the Peerless XT25 to the Visaton WG148 and possibly ID the adapters i printed?

When winding output transformers I've come across the term "spiral winding" of the secondary windings.
The idea is that sometimes the secondary windings won't fill the whole width of the bobbin.
This will cause increased stray inductance, and the remedy is spiral winding on parts of the bobbin.
So, my question is;-is this what it would look like?

For years, I've heard a sort of low-level gritty harshness from solid-state electric guitar amplifiers, when set for clean tone.

I'm talking specifically about solid-state, all-analogue guitar amps that follow the typical recipe: op-amps in the preamplifier, and an IC power amp (or a rarer discrete power amp stage).

For a long time (decades!), the cause of this phenomenon eluded me. I didn't know what caused it, I didn't have the test equipment to capture it, and not every musician even heard it at all.

So it was basically a case of "He said, she said", and that is a very unsatisfactory situation for what is fundamentally an engineering problem.

I think I now finally understand the cause of the harshness I've heard so many times, and I'd like to talk about that in this thread. Hopefully this is of interest to other people who want to build solid-state DIY guitar amplifiers, or simply want to understand them better.

The starting point for all of this is the actual electrical signal from an electric guitar. Exactly what does it look like?

Fortunately for me, Rod Elliott, a name familiar to most DIY electronics enthusiasts, had made a number of measurements of e-guitar signals, with the intention of finding out the amount of voltage that could be expected from a typical e-guitar.

While Elliott's goal was to calculate peak and RMS voltage from a guitar, he also posted screen captures from his oscilloscope on his website: https://www.sound-au.com/articles/guitar-voltage.htm

There are a lot of interesting things to be seen in those guitar signal captures.

More in the next post.

-Gnobuddy

He died of a heart attack this weekend.

This is sad. Rick was one of the 3-4 people that were present at my first experience in hifi, about year 2000. I've told the story before a few times, but;
We met in Ft Wayne down on HWY 24, IIRC. Rick was in town from NC visiting his folks in FW, who still resided here at that time. JeffB, Rick, myself and another fellow I don't remember met at Applebee's. 4th guy left after lunch. Rick's folks eventually moved to Indy where we also met once more about 2005.
After lunch we went further into town to a HiFi shop which is now closed. I heard Jennifer Warnes played on B&W Nautilus 801, via a massive McIntosh tube amp. I was the inexperienced one here, and Jeff/Rick agreed that the treble was sssibilant, and that the bass was okay but didn't extend all that deeply for a 15" woofer. We all thought the mid was spectacular.

He was what I consider one of my mentors, and will be missed. He has touched many a soul through his speaker-designing business, and I've not heard of a disappointment with any of his products.

He really knew his stuff.

Wolf

Hi my neighbours kids are driving me crazy, tried asking parents to intervene with no joy
Bearing in mind I know nothing about audio et cetera, I'm aware that there is certain sound which only children can hear and which may deter them from the area around my fence
Is there an app, combined with a high volume Bluetooth speaker, or something anyone can recommend that will put an end to my misery 😟
PS I'm in the UK

NOS in the box. Currently using EH 300b.

A little while ago I stumbled onto a company called Gobel and their bending wave speakers. They use carbon fiber plates as the medium for sound instead of something like cardboard or foam. Can exciters drive something like that? If not, how the heck are they doing that? 🤔

Hi guys, got this as faulty from online. Buyer stated disk just spins and does not read CDs I was hoping its just the blue cap under the laser but no joy!

When I put a cd in it just spins and laser does not go up or down and I cannot see a bean either.

I've checked most of the rails and on the chips and they all seem ok as far as I can see.

Any experts on these old players? Its 100% not the cd mechanish as I tried that in a working unit and it was fine.

Ive been using CD65DX service manual but the device is CD75 II

Any help appreciated.

I have a late 1950's Neuman U47 mic that has gotten noisy. Obviously, this mic deserves the best components available.

I don't have a scope, so can't test most thing, but I figure it might be a good idea to change the 64 year old electrolytics in the power supply.
Sure, they might still be fine, and they don't meke 'em like they used to, etc, but it seems logical to do it now.

There are two 1000uf / 50v, and those are no problem. I can easily fit Nichicon LKG's there.
However, there are also four 47uf / 250v axials, and I'm having a very hard time finding a suitable replacement even in a radial cap, hence this post.
The original caps are FRAKO GPF series, (polarized electrolytics) and are no longer made. I saw some vintage nos ones for sale, but what sense does it make to buy really old electrolytics?

I would love to pop some polystyrene's in there, but space is a real problem.
(I'm also not clear on whether I can use non-polarized caps there.)
Even a really good electrolytic, like maybe a Mundorf MLytic, is too big. The max diameter I can easily fit is about 20mm.

One alternative would be to use decent electros (or smaller film caps and glue them to a different area in the enclosure. However, that would require pretty long leads, maybe 4-6". Would that be a problem?

Or maybe use a bit less capacity? I assume these are bypass caps, yes?
Still Neuman surely knew what they were doing, so....

------------------

I may just change the big caps first, and see how it sounds, but even if that cleaned things up, should I consider changing the others as well?

-----------------

Anyway, does anyone know of a really good, but fairly compact, cap I can use? (axial or radial, I don't care.)

- thx

Hello everyone. I own the amplifier in question. A few days ago I opened it for cleaning and since then I've been wondering if it might be worth updating it, perhaps in the power supply part by replacing the original 10000uF capacitors with others of greater capacity. This idea comes from the fact that I realized that with my Infinity KAPPA 8, by activating the switch that lowers the impedance of the woofers, the sound becomes richer in bass but it seems to me that it loses detail in the medium-high part, as if the amp was at its limit. Yet no protection LED lights up, nor does the cooling fan trigger any protection. What do you think? Other suggestions for possible improvement?
thank you

Received this amp... Output Stage damaged.. No Fets inside. Drive Board one mpsa 56 was burned and the 220ohm resistor..
Problem is now,That If Input the Driver Card in place,without mosfets, the 220 ohm directly Starts burning...cant find the Problem.

Hi guys,

I recently acquired a "non-functional" Technics SL-D1 turntable, that I want to fix up.

First thing I did was spraying some contact cleaner on the potentiometers. While cleaning up the internals, I noticed that one of the capacitors(C1) appeared to look suspect (bloated appearance) so I replaced it.

The problem now is that the turntable is spinning way too fast at both 33 and 45 settings, no matter how I adjust VR1, VR2, and VR3(pitch control dial).

Even with all potentiometers all the way to the "-" position, the speed is too fast.

As I did not really try adjusting the speed before changing C1, I'm not sure if that was the cause of the problem.

Would appreciate any suggestions on how to go about troubleshooting the issue..

Here is the schematic:


And the PCB diagram:

I'm jumping in the deep end tackling a BLDC controller circuit to replace the original analogue controller of a Technics SP10 MkII turntable. If it is assumed that I can successfully emulate or even improve (!) upon the stock circuit's performance, what additional features would you deem desirable in such a controller?

It is likely to be (but needs not be) a stand-alone controller that bypasses the on-board switches and replaces the existing power supply.

Your ideas, please...

Marantz PM7200 Buzz Sound(Like a radio during tuning)
On both channels
Even when volume is 0
Constant noise on all volume levels
On both A and AB modes

Dredging up more of Nelson's past. I pulled the following quote from someone on the DIY list (old Bass list):

"Have you heard of active absorbers? Not me, but my colleagues seems to be familiar with this concept, and apparently the idea is 15 years old. It seems like the only logical solution to me.

Nelson Pass seems to have designed the "Shadow" by Phantom Acoustics. (anybody heard these?). Located in Auburn, California."

I searched around a little on the web but didn't turn up anything.

What's the scoop?

Thanks,

Russ in Tucson

Repairing the power supply on a HD1200/1, think I have the FETs identified (original FDP8870 no longer in production, going with IRL7833), but I'm getting conflicting data on the driver transistors. The one marked "12W" is blown, from what I can tell it's either a PNP or an N-channel FET.

Hi,
I have a XO design (OSMC) that calls for specific coils. Looking at the prices of suppliers, I'm wondering if I could wind my own? What would be the choice of "I" laminate, bobbins. Are there suppliers that would supply the laminate and bobbins? UK/EU
I have an inductance meter and am in the process of building a milliohm meter - Login to view embedded media https://worldradiohistory.com/UK/Practical-Television/00s/Television-2005-07.pdf (page 534)

Many thanks.

Earl

i have Crystereo Lava headphones, it connects to any device without any problem but i cant hear any sound, speakers are fine, with AUX cable when connected to audio jack headphone is fine but on bluethooth no sound, play and pause button works.
kindly help me with this problem, if its QCC3034 chip issue or something else?

i have Crystereo Lava headphones, it connects to any device without any problem but i cant hear any sound, speakers are fine, with AUX cable when connected to audio jack headphone is fine but on bluethooth no sound, play and pause button works.
kindly help me with this problem, if its QCC3034 chip issue or something else?

I am interested in building a audio inputs switch (audio selector). I have experience in digital circuits, but not much in analog circuits, but I am passionate about audio. So I need a little help.

Had thought of using a pair of 4051 with 8 inputs each, and also a small micro controller (atmel avr or microchip pic). It would be better to use the 4052? (I prefer to have 8 stereo inputs with two 4051, one for each channel)

Someone can recommend me any design or schematic?

I have to put a "audio buffer" or preamp? in the output? in the input? in two places? (if so, could use a NE5532?)

Any information is welcome: schematics, designs, tips, ideas... (I need help especially in the analog audio part (input or output preamplifier, buffer...)

Thanks you very much for everything!

PS: The 4051 has an acceptable quality? or make noise in the audio?

Thanks! bye!

Son wants to build an audio amplifier using tubes. I'm a total noob when it comes to tubes. So we got ourselves a EZ80 rectifier and a few other tubes. First things first we wired up the EZ80 to the transformer. 4-5 Pins to 6.3VAC and Pins 1-7 both to 120V AC. The ref wire output of the transformer (120VAC ref) was grounded to the body. When switched on, we only get 62VDC at pin 3 (with body Ref) . Any idea why?.

I am starting a new project, and as before, I am going to share my thoughts, results, successes, and failures, in the hope that others can benefit.

In my first speaker project, I established a basic architecture for a flexible 3-way system. A speaker stand with a Hypex 3 channel amplifier, a replaceable head unit containing the midrange and tweeter, and a separate bass box. https://www.diyaudio.com/community/threads/new-active-3-way-hypex-and-sb.352767/ My first system used good quality drivers, but I fully expected it to be a learning experience. I was pleasantly surprised at how good it sounded.

My second project (TXT) was a new head unit using much higher quality drivers. https://www.diyaudio.com/community/threads/new-active-satori-textreme.366347/ I incorporated improved cabinet construction techniques, including a butyl-aluminum damping layer on the interior. I was extremely pleased with the overall performance of the system.

My third project (Twin-8) https://www.diyaudio.com/community/threads/new-project-tower-3-way-with-twin-8s.378223/ was intended to address several questions/needs I had: (1) I wanted to design a speaker which had good Power and DI performance from the outset, using VituixCad to fully simulate and optimize the response. (2) I wanted a self-contained speaker which would be portable, and serve as a backup to my main system.

After comparing the Twin-8 to the TXT, I did some further refinement of the TXT DSP filter, and I was able to optimize the DI and Predicted In-Room response of the TXT system.

At this point I have learned many things about how my ear/brain perceives thing in my room. One thing I have learned is that good DI, ER, and PIR response is important up to a point. Once some level of smoothness is achieved, once it is within +/- 2 dB or so of some target response, additional improvements do not mean much. Another thing I learned is that high CtC spacing of 1.2x wavelength works well in practice, even though it looks weird. I learned that there are subjective differences in drivers, and once two systems are optimized to a highly refined level, the differences in drivers starts to have significance. I learned that with flat-baffle-mounted tweeters, it is possible to achieve acceptable DI and PIR performance, but it is not easy.

I am very curious about the extremely low distortion drivers from Purifi. The Purifi PTT6.5M has at least 10 dB lower IM distortion than other high end midrange drivers such as the ScanSpeak 12MU Illuminator, Satori MR16P, or Eighteen Sounds 6ND430. I am very curious to how this Purifi driver performs, objectively and subjectively.

===== ======= ====== ======
Index to this thread

Design constraints for this project post #280
https://www.diyaudio.com/community/threads/purifi-waveguide-project.394174/post-7359847

Conventional cabinet prototype (Bevel box) post #2

Early filter simulation post #31
https://www.diyaudio.com/community/threads/purifi-waveguide-project.394174/post-7233464

Free standing waveguide prototype (Foam donut) post #33, #44, #65, #106
https://www.diyaudio.com/community/threads/purifi-waveguide-project.394174/post-7260700
https://www.diyaudio.com/community/threads/purifi-waveguide-project.394174/post-7286772

Mid box construction post #38, #160, #175, #177
https://www.diyaudio.com/community/threads/purifi-waveguide-project.394174/post-7278809
https://www.diyaudio.com/community/threads/purifi-waveguide-project.394174/post-7318402

Modifying free standing waveguide prototype with sharp rear termination post #106, #111,
https://www.diyaudio.com/community/threads/purifi-waveguide-project.394174/post-7294235

Selecting free standing waveguide concept post #171
https://www.diyaudio.com/community/threads/purifi-waveguide-project.394174/post-7316583

Waveguide construction post #176, #188, #194
https://www.diyaudio.com/community/threads/purifi-waveguide-project.394174/post-7318998
https://www.diyaudio.com/community/threads/purifi-waveguide-project.394174/post-7332329
https://www.diyaudio.com/community/threads/purifi-waveguide-project.394174/post-7333484

Driver measurements in final cabinet post #196
https://www.diyaudio.com/community/threads/purifi-waveguide-project.394174/post-7349489

Description of woofer system post #230
https://www.diyaudio.com/community/threads/purifi-waveguide-project.394174/post-7351827

Final construction photos post #262
https://www.diyaudio.com/community/threads/purifi-waveguide-project.394174/post-7357092

Measurements and listening evaluation, Round 1, post #292
https://www.diyaudio.com/community/threads/purifi-waveguide-project.394174/post-7382731

HI,

one Set 11€ + shipping

Shipping to germany 2€ (padded envelope and not tracked / insured)
Rest of world 😎 4€ (padded envelope and not tracked / insured)
... when more sets, I will recalculate the shipping costs.

Exept UK, only parcel and customs paperwork for me, around 15€.

bump

Hi all !
after my loudspeaker lost a fight with the cat of my wife,
it's time to start a new project

so.... Design rule nr.1 steel mesh to save the drivers.

My old Speakers where driven by Hypex FA Amps and one issue i had was that watching youtube often resulted in muting when there was
a rest in some videos, not in musik clips, in spoken clips like DIY videos.
i never was able to solve it, therefore i thought i might go passive this time.

Surfing around at troels website i found those high efficeny speakers. like the Faital 3 WC -15 which makes me curious.
so , how (or why) they are different against, eg. Ekta Grande ?
I can imagen that the soundstage is bigger and the location where the instrument exactly is, is not so good in case of the big baffle,
But my fantasy lacks a bit to understand more.
The lighter membran do no omph omph - ok i can understand. its like flatten the impedance peak(s) in a vented system.

i always thought that fast transient attacks are in general based on the alignments ( 0,707 - 0,58 - 0,500) and only secondary at the chassis.

anyone able to explain me the benefits

thank you richard

Im in the process of setting up my amp. It has 2 amps.
One based on the Rod Elliot P3A and the other is based on the TDA7294.
The speakers are
1. A pair of Eminence Gama 15 Inch woofers. (In a massive horn cabinet).
2. One pair of 8 inch full range speakers.
3. One pair silk dome tweeters peerless.
4. One pair Eminence CD 2002.
The idea is to split them between the the two amps.
On testing I found that the TDA7294 gain is crazy (Max value as per data sheet). My bluetooth volume goes from 1 to 30.
I can not play even 2 on the TDA without it sounding too loud.
On the P3A I can take the volume upto max in short bursts.
This forces me to make a call.
Do I reduce the gain on the TDA or increase the Gain on the p3a. (Finally there will be a balance control anyway). Reducing the gain on the TDA seems easy and less complicated to me.
My question is will reducing the gain improve sound quality i.e. lower distortion. My exp with old amps is the slower, lower HFE transistors with low gain seem to work better i.e. less distortion and very clean sound.
Sorry for the Noob Question.
Both boards are being powered from the same transformer. Separate PSU boards. 35-0-35 DC @ 15 amps.
Any tips on how to increase the gain on the P3A. i.e. which stage ?. Or all stages.

I’m needing some help, my first time using the TDA7294. I’ve installed them into a Yamaha R-300 which originally used a STK2030 output and STK3042II voltage amplifier. The amplifier has +/- 34.5v rails. The boards were built using all of the components I sourced, so every piece is an authentic device, not a kit from China.

On the first power up the protection relay clicked and I measured less than a mV of offset on each channel, woohoo! Then I sadly saw I had a very slight amount of hum, I’m measuring about 430mV AC on the outputs, so about 0.02 watts worth into an 8 ohm load.

Also, do the TDA7294 run hot when sitting idle? Or are they getting hot because of the hum? Most mosfet amps I’ve come across run hot, so I was wondering if it was the same since it uses mosfet outputs. Not sure how warm I should let the heatsink get, but after about 3-4 minutes I put a fan on it which kept it cool. Maybe not enough heatsink for two chips. The original amp was rated 30w x 2 and I’m getting a clean 50 watts, we’ll clean minus the hum.






All of the grounds on the amp connect on the same ground trace; those being ground for the power supply, negative speaker output, and ground for the input. Even though they all connect together with the traces, I also ran wires from their holes to each other on the board and all the grounds for both boards met at one wire that went directly to the chassis, right here. You can see the screw right under the heatsink. I went for as short of a run as possible.


The audio input for each board came from where the input pins of the old STK3042 would have been. The wire going from that position on the board to the TDA7294 board is a shielded coax cable, shielding being connected to the ground of the TDA amp board.



Here you can see the output of the amp, the trace is fuzzy since it has that 430 mV of hum riding on it.



Any suggestions on why I have that hum? Any suggestions as to how to get rid of it?

Secondly, should the amp chips be getting hot just sitting idle? If so then I won’t worry about it. If the hum is the cause of the excessive heat that would be cool.

Dan

Hello,

Can please someone explain what happens when SE:SE interstage transformer DC rated current is exceeded?
For example, Hammond 126C interstage is rated for 15ma unbalanced DC current, what happens if there's 20ma flowing through it?
Does it saturate the core and low frequency response is affected (essentially inductance become lower)?

Thank you,
Igor.

Thanks to the opamp control this power amp has very low distortion at all levels.
The opamp is OPA189. It has very good qualities.
The output stage is one 2SC5200 and one 2SA1943 in push pull Class AB.
Max output with low THD is 29 Watt.

The power supply is based on a toroidal 2x18VAC transformer.
This gives like +/-24 Volt.

I haven't built anything in a while and am getting the itch. Not looking for a kit just a schematic. Any suggestions?

Here is my YouTube channel with builds and repairs.
https://youtube.com/@cytowing3353?si=LgjNTmLKVSQldSOm

Hello,

I have a tube phonostage, the PAS Z-PH10 from Erhard Audio, as part of a complete PAS Next Gen kit from him. The phonostage output sounds muffled, like the high frequencies are very suppressed. I have reached out to Erhard Audio and he mentioned he did not have any suggestions for me, never encountered this problem before. I tested every single resistor before I installed them to make sure they were the correct values before installation. I have reflowed every solder joint in case there was a cold solder joint. I am using brand new 12AY7 tubes from Electro Harmonix and I tried swapping their positions with no change. Erhard Audio told me the RIAA section of the unit is R4, C3, R8 and C6. I did try replacing C6 already because the original cap was specified as a 5% piece and I happened to have 1% caps of identical value on hand, but that also made no difference. I have plenty of resistors on hand if I need to swap any parts out, and I have spare caps if I need to swap them out. Also, not sure if it makes enough of a difference, but the voltage out of the top regulator section is 220v instead of the specified 240v. Voltage in to regulator is 267v. I get the impression Erhard audio was not concerned about the difference. Could just be difference caused by wall voltage of course.

I am confident the problem lies in the phonostage as I can use my solid state phonostage on the Aux input and the preamp section sounds just fine. The problem is only when using the tube phonostage. Not just dark, but very muffled like when your ears are plugged up. It's also odd that the problem is in both channels, so whatever mistake I made or whatever bad part was used...well, I must've done it twice lol.

Attached is a PDF of the phonostage schematic.

Any suggestions?