After much fiddling around today, I found that my DCX2496 was producing hiss on one of the channels... It sounds a little like white noise.

The strange thing is, when I first turn the unit on, it's fine, and it only starts making noise after 30mins or so.

After searching around, apparently this is caused by the output PCB shorting against the case, so I opened it up, and lined the case with electrical tape.

Now, after putting it back together, I still get hiss! 😡 It's only doing it on a single channel, channel 4. Now, as I'm using 4 channels, I simply replugged the XLR into channel 6 and no more hiss...

Now, I'd like all my channels to be hiss free, how can I fix this?

NOS(?) tube with two white spots. Both near the getter area.

The first white spot is around a dark points on the metal construction of tube, you may see one point on the photos 1 and 2.
The dark points are close by, and big white spot on glass is the result of the merging of both areas.

The second white spot is exactly on the opposite side of the rib of tube.

What is it?
Is it ok to use tube with it?

Hello, i collect a bit Peerless xls drivers.. no Thymphany copies..

Building soon 2x "Thor" Boxes for my 830500 drivers.. they are actually new oldstock aswell.. another project i also will try is "sonosub" but with passive radiator from Scan-speak,. so 4 cabinets total.. just to try out what suits me best.. the subwoofer will be used for music, and movies.


Have also an old 1x 830452 10" with fiber dustcap and a 12 " peerless (425g) passive radiator that i will use in a passive box build im making right now..


The last one i have is a xls10 from a Gallo acoustic subwoofer.. it is playing lovely in a closed box on my stereo room at the moment.. just need to make a finish on the box.

3 out of 4 channels distort .

3 channels I can bias 1 channel will not bias .

Any ideas where to start ?

Through looking at logic IC's on Mouser , I found this "new" Logic Family: HCS ,
next gen HCMOS.

Maybe not audio related , but I'm sure some of us older guys still use discrete
HCMOS IC's for controling audio relays and switches.

From their site :
The HCS family is an update to the HC logic family. HCS logic modernizes
multi-gate logic functions to meet the needs and demands on today’s system
designers. Each HCS logic part, numbered SN74HCSxx, is a pin-to-pin drop-in replacement for existing HC logic parts, with no need to update designs or change development tools.
The HCS family was designed with automotive applications in mind and is the first TI logic family to launch with a complete line of both commercial- and
automotive-grade parts.
https://e2e.ti.com/blogs_/b/analogwire/archive/2019/11/12/achieve-simpler-and-more-robust-designs

I must be missing something : "complete line of both commercial- and
automotive-grade parts" . A whole family seems a bit much , only 25 on their site
gates , flipflops , buffers, encoders/decoders.

Quiescent current (IQ) for an HCS part is just 2 µA max, compared to 20 µA max for comparable HC logic. Each device in the 2-V to 6-V HCS family consumes 95% less power than its equivalent HC logic function, making HCS logic devices much more suitable for battery-powered designs.

They say quiescent current of just 2 uA , but that is low freq or not doing much.

https://www.ti.com/sitesearch/docs/universalsearch.tsp?searchTerm=74HCS#q=74
HCS&t=everything&linkId=1

When I look at the data sheets , lower quiescent , extended temperature like 54HC
-40 to 125C, and all Schmitt trigger inputs.
Of course 74HCS00 = 74HC132 but with lower current , ext temp
74HCS04 with ST is 74HC14 is 74HCS14
74HCS32 = 74HC7032
74HCS08 = 74HC7001 and so on.
When I compare datasheets , it seems the hysteresis is smaller than regular HC. A
few ns faster but power dissipation capitance per gate the same.
I haven't had the chance of getting my hands on them and do some testing .
Has anybody used them ?
Is the current less , near the trigger points ?

It seems like a very interesting upgrade , no HCT , but who still uses that ?
Schmitt trigger inputs are the best. And about the same price as the regular HCmos.

Today I found a solution and share it with you. hope it helps your job.

BMW Most 25 interface amplifier platform. Designed based on Logic 7 and this 9 channels speaker output, two channels support BMW woofer which achieved RMS Power 7X86W(4ohm),2x160W(2ohm). and could support CIC, NBT, EVO audio system, Harman, Alpine CD/DVD player, Dolby, DTS decoding system.

1. Designed according to Logic 7, some power connector, same most interface, same speaker output connector
2.9 channels speaker output, two channels support BMW woofer(2Ohm,4Ohm)
3. Support CIC, NBT, EVO audio system
4. Support Harman, Alpine CD/DVD player
5. Support Dolby, DTS decoding system
6. Install with the same cable as Logic 7
7. BMW system programming is as Logic 7
8. The same interactive interface as Logic7 (EQ, BAL, FADER, Volume system)

Hello

Could somebody give me the wiring of straps on the amplifier for a DD12 in 220v setting.
I have one in 110v setting, and I want to modify it in 220v for french voltage. I put some photos of the straps :

The Velodyne DD12 amplifier :



On the components side :




The straps, near the orange caps



This is the 110v cabling
Who could give me the 220v cabling...

Thanks

Philippe

Hi there
I am wanting to build a 3 way speaker with a transmission line as bass maybe from about 30 hz tuning frequency using a Morel Ultimate UW1058 (25hz to 800hz)

with a conventional sealed box for a midrange - using a Morel Supreme SCM634 ( 50Hz -7kHz)

and a tweeter ( not concerned with that yet)
My question is 2 fold
1) Where would I look to cross the bass to midrange , there is no info out there as to how wide (octaves) the bass band can be with a TL speaker

2) if I cross to the midrange at say 150 hz do I tune the midrange box to the 50 hz resonant frequency as claimed by the speaker manufacturer or do I tune the box closer to the crossover frequency I want?

thanks in advance
Clive

Hi all. I recently bought a Tisbury Audio passive pre to use with my Quad 306. I'm really liking it so far, but I have a quick question if anyone can help me out.

The specs on the website state that the output impedance at full volume is 0 ohms. The unit has fixed attenuations switches on the bottom to reduce the signal by a fixed -10 dB or -20 dB.

So, my question is, if I set the switches to either -10 dB or -20dB, at full volume will the output impedance still be 0 ohms? Or is the output impedance affected by the fixed attenuation?

Thanks!

OK,

A friend at the monthly HAM swap meet has a very clean, restored and calibrated AC millivolt meter. Dual channel 30uV to 100V. (the meter actually has two pointers). Meter has AC and dB scales.

I understand that these meters really just do one thing, probably very well, for measuring minute levels of average AC present.

What can I use this for? I was thinking along these lines:

1) Quickly evaluating power supply ripple while breadboarding and tweaking.
2) Having two channels to compare input to output.
3) Maybe some applications in negative feedback?
4) Finding crosstalk?

Is this a boat anchor, or could it be handy tweaking things? I'd have to learn it, but it seems easy.

I'm trying to desolder a couple compnents on a Korean DAC and cannot seem to melt the solder! The DAC appears rather well made commercially (Calyx) and I'm using an OKI Metcal PS-900 with Smartheat. The Metcal has always been very good about delivering the right amount of heat to the soldering task but I can't get the solder joint to melt. With a lot of flux and a good size tip wetted with 60/40 I can get it to partially melt for a moment but not enough to do anything with.


Is it possible a soldering method was used in the factory that is ultra high heat that a Metcal just can't achieve? If so, what are my options? Will a computer repair shop with Hotair Rework station be able to manage? The User Manual specs don't even specify the tip temperature range on the Metcal... that I can find.

Joe does people clean their PU-tips today? Ive read about using Isopropyl Alcohol (Ipa) on a brush.
Also using Magic Eraser? - I dont know what it is or how to use it.
I wonder if one could use electrolysis or ultrasound.
Could one just put a shallow tray om the platter with solution and a cotton pad for the needle to rest on, and let the vibrations or electrolysis do Its Magic? I Will try to update the post with good sugestions.
Cheers!

Magic Eraser method: Magic Eraser is also sold as Magic Sponge, Miracle Sponge, Stain removal sponge etc.
Here is a Guy showing how its done at 2 minutes 35 seconds:
How to Clean your Record Needle - YouTube

I would like to ask if it is possible to use the stator iron core of a motor as the toroid core for a transformer. The original windings from a bad motor would be removed, and a single coil would be wound in such a way, as to keep the magetomotive force evenly distributed along the axis of the entire core. Such a core is segmented. In each segment a constant number would be wound. The segments would cause some magnetic flux to flow through their air gap, but that should be very small, as the permeability of air is too low. The secondary would be wound to also keep the number of turns per segment constant.

The electrical difficulty of such an arrangement is that each segment would act as an independent transformer to some extent, but this independence is slight, as the main flux passes along the entire core axis path.

If a rotor core is generously wide, one can saw off the segment sides to leave only a toroid which should behave like other mangetic toroids. The difference would be that such a core would consist of a stack of rings instead of long strip wound on itself to form a ring.

I am looking to buy a "slim" floorstander kit and i have been really interested in troel gravesen designs and was pretty shure that the Nomex 164mkii was the speaker i wanted untill he recently released the "Discovery MTM" at a little bit higher price. Now i am having issues choosing, i feel like the things that differentiate them the most are the type (TMM or MTM) because they have simular quality drivers. I will use them in a small bedroom around 10m2 so the vertical possition will vary around 1m (depending if i am laying down or sitting up). I use my speakers LOUD from time to time when watching movies 105-110db peaks.
I am still leaning towards the NOMEX 164 MKII because i like the look of a leaning speaker but if anyone have any suggestions i would be glad to have someone elses opinion on this and if they think another kit might be suitible i am open for suggestions.

Nomex: NOMEX-mkII
Discovery MTM: Discovery-MTM

I recently moved to a new house, which has an area that I get to use for a dedicated home theater. It's a larger space than the old living room, and my subwoofer, a 10" Dayton Ultimax in a sealed box, just doesn't subwoof enough anymore.

So I decided to upgrade substantially and pre-ordered a pair of Stereo Integrity HT-18 v3's. I have a QSC PLX1602 (500w x2 [or 1600w bridged] into 4 ohms) to power them (for now; might get a second amp later). Now I just need to figure out what kind of box to put them in, and with that I could use some suggestions.

Box Size Constraints:

I'm planning to build a bar (as in, the kind one sits at to drink) just behind the front row of seats, so that the bar stools function as a second row of theater seating. The top of that bar is going to be on the order of 10' long, 40" high, and 18" deep. It has occurred to me that the structure of the bar would be a great place for a subwoofer, and it could be quite a large one. If I make the lower 2/3 of the box protrude from the front (screenward) side of the bar, I have close to 50ft^3 (1400L) to work with, without really taking up any otherwise-usable space.

There is also space up front with the LCR speakers. Not enough space for a second colossal sub, but enough for a decent-size ported box. So I have the option of using one driver in the bar structure, and one in the front of the room. That's what I would prefer to do if I can come up with a design that takes advantage of the volume of the bar structure with one driver, and a smaller design that should be possible to integrate with it.

Room Dimensions:

The room measures about 20'x25', with a bathroom built out of one of the corners, so it's really about 420ft^2. It has a suspended ceiling with fiber board tiles at 8' high, and the floor is carpet on concrete. The theater area itself takes up roughly 15' square, with the TV on the 25' wall, and the 20' wall on the right.

Performance Goals:

It's a home theater subwoofer and I like bass, so of course I want it to go as low as possible and be loud. Flattish to 20hz is a requirement, and I'd like to have tangible output in the mid-teens.

I've spent some time modelling boxes in Hornresp, and I've convinced it to make some squiggly lines that seem to correlate to a tolerable frequency response, but I'm realizing that I don't know what I'm doing enough to know broadly what kind of enclosure I should be trying to design. So that's my biggest question: what kind of thing should I be trying to make?

A big, standard, vented box seems to model pretty well around 22ft^3 (600L) per driver with a 14hz tune. With 10' of length available, a transmission line makes a lot of sense to me, since I could actually fit a 14hz line with one fold and no taper. That would actually be easier to build than a vented box in this case. A tapered or mass loaded line looks a little smoother in the sim. No matter what kind of box I model, it seems to want a tune between 14 and 18 hz, and the response looks pretty good with a volume around 400L, slightly better around 600L, and excessively underdamped (I think) if it's much above that. Is there anything I could do to make better use of a larger volume?

I haven't yet put in the work to learn how to make horns work without being inconceivably large. Is something like a tapped horn worth looking into for these drivers?

Looking for a White Noise Audio WNA headphone amplifier board or kit. Thanks in advance. Rick

Hello to all ,

I have a pair of these loudspeakers on my system , and I am questioning about these fake corrugations . I an saying fake because the backside of the cone is totally smooth . So there is some extra thikness from place to place , on the front side of the cone .

Anyone knows the purpose of that extra thickness ?

For me , it seems useless . I'm thinking in sanding the conehttps://files.diyaudio.com/forums/images/icons/icon7.gif

Thank's in advance .

Hey guys had great success in the past using AD844 (with no nfb), just want simple this time, got a PCM1796 dac, looking for what's the best dual I/V opamp today. Even singles at a crunch, if I get a Brown Dog converter boards.


Just looked at the old AD812 seems to have some good specs for I/V duties.
What do you guys think
145mHZ
1600 V/us slew rate
50ns settling time
-90db distortion
can't find out if it's unity gain stable or not.

Cheers George

https://flic.kr/p/2mKYiS2 https://www.flickr.com/photos/64593884@N08/

Sparkler Audio S515u CD Player (2 units Power Supply + CD Player) $2,100
Hand Made in Japan

Hello everyone

Being unable to create myself the HT90 directive in ultra linear mode.

If anyone could post it here that would be fantastic.

I found this one but only for the pseudo triode mode 😡


* KT90 LTSpice model .subckt
KT90 P G K
Bp PKI = (0.01798272846m) * uramp (V (P, K) * ln (1.0 + (- 0.1903672493) + exp ((0.1218980633) + (0.1218980633) * ((104.4846442) + (27.71095382m) * V (G, K)) * V (G, K) / sqrt ((- 1.365059137) **
2+ (V (P, K) - (- 19.04749222)) ** 2))) / (0.1218980633)) ** (1.412945234)
.ends KT90


Thanks in advance

Hi guys

Amp going in protect when bridged. Both channels works flawlessly if tested in regular stereo mode, puts out full power per channel.

Does not protect in bridge mode if there is no load connected. I can see nice big sinewave on the scope.

When using 4 or 8 ohm load in bridge mode goes straight into protect. 😕

Pre-amp section seems fine with stable +-15v.

Any ideas ?

Schematic is attached.

Hello all, OK, so I got myself a pair of Duetta Signatures the other day - always wanted a pair. Never could get my grubby hands on 'em, tho, until a few months ago. Drove four hours to pick them up. Had a whole 5 minutes to hear them. They sounded nice. Didn't really them play loud, or on anything crazy. No buzzes anywhere that I read about...so brought them home. Set them up, and took the covers off. One cover had a little crack from previous shipping damage from prior owner. Simple fix with a little sandpaper and Gorilla Glue and some gritty flat black spray paint and I was in business again. I also realigned the screen so I wouldn't see any annoying screen waves (Apogee owners kow what I am talking about). Did the other speaker and they looked 1000 times better.

The loose Tweeter/Midrange ribbon was next - it was loose and dancing around, and it concerned me a bit. The top 9" is tilted back (to give the tweets a little vertical dispersion) and runs over a piece of foam as it make the tilt back. Well foam was gone, so I went to Menards and got some Air Conditioning foam and glued a piece in and it took all the slack. No more loose Tweeter/Midrange. Yeah. All done.

So I sat and marveled at my purchase. Put on some Jennifer Warnes (Famous Blue Raincoat - man I love this cd)...It sounded great...until I raised the volume - her voice sounded like Rod Stewart. What the hell was going on? It was buzzing right on on her voice only. No where else. I was pissed. How can I miss this?

Anyway, started looking around and could really find any fix that I wanted to try, until I came across a crazy fix that was taken down from an Apogee forum I was reading. It supposedly was lost, and nowhere to be found....Finally, from some good detective work I tracked down the lost thread poster on DIYAudio (what are the chances?) A German gentleman that goes by taotao.

Ok, enough of the history, what the fix? Taotao had an idea to inject a flowable silicon into the deteriorating foam between the wooden clamps. He used some two part mixture, but one of the guys here suggested maybe a silicon that he used for windshield crack repair. I went to Autozone and purchased all they have - four tubes. Called Permatex Flowable Silicone Windshield and Glass Sealer - about $5 a tube. It actually flows ok, but needed to be thinned. Now taotao said he mixed his silicone mixture with 1/3 part silicone oil. I found some 1000ml of Silicone oil on fleabay for $5 shipped - it is from Canon (Fuser Oil S-400) and used for copiers and printers. Anyway, I put together a test batch of this mixture and noticed it flowed real well...let it dry overnight. In the morning, it was very soft, and I thought it would work perfectly.

Went to Meijer and picked up one of those kiddie medicine styringe, some 1/4 clear tubing, and a basket ball inflator needle. Pic attached. Laid teh speaker on its side and supported it so it would not tip.Sucked up some silicone goop and laid a nice bead over the front foam, right on top. The foam sucked up the silicone. I just kept laying more beads until the foam cavity was filled. Then did the other speaker, and let it dry for 6 hours. Then I turned it over and did the other front side... Didn't bother with the top or bottom foam...

That took care of the front, but what about the back? Since this mixture is a bit less viscous than honey, I let it drip down the backside foam. I stood the speaker up and injected the silicone along the back clamp corner where the foam seam is, and let it run all the way down the speaker. This took a long time as I couldn't see the silicone when it got to the bottom. Just gave it ample time (an hour). Again, the silicone drip was done through the top of the backside foam corner. I used a lot of silicone on the back clamp drips. All the excess just oozed out onto the clamp face, so no big deal. After enough drip time, I set the speaker back onto its side and allowed the silicone to drain into the foam seam. Then I did the other side and the other speaker, and let them dry a good 6 hours before trying them out. Took me all day today and a few hours last night.

Anyway, no more buzzes...A shout out to taotao - you ROCK... some pics are attached... This worked for me - and a few others - again, your mileage may vary...

Hello, I'm looking for information on how much flat frequency response (where speaker performs without colorations) I need to leave below crossover point if 24 dB/octave slopes are being used.

Rod from ESP recommends at least one octave of adequate performance below a crossover point.
Since I'm am planning to use steep 4th order 24dB/Oct slopes, could it be possible to push the crossover lower?

Cheers,
Stefan

I just got my waveguides from a 3D printing service on Etsy and I was rather disappointed with how rough the appearance is. In your experience is this normal? Below average?

Hello everyone, I present my problem for which I ask your advice.
I have built a 101 by Rod and find it a good design, especially simple and good sounding with R 8 speakers.
I am now using Yankee audio planars which measured at rest give me R2.7.
I thought I'd use the vas part of Rod's 101 to drive three pairs of Hitachi 2sk135 and 2sj50, rebuilding the pcb to accommodate the six TO3s. I have 70V on the Hitachi power amps and 58V regulated on the vas to the MJE350 mosfet driver.
I set the bias to 200ma per supply branch.
The sound of the Yankee is spectacular, never heard such beautiful, precise and impressive midrange. After listening for a long time it seemed to me that the bass was a bit behind the music scene, a bit attenuated. I have two 800VA toroidal tubes and 90,000 micro caps per channel. I tried biasing the mosfets to 300ma per branch, but the bass went back even further.
I did some measurements, on a resistive load of 8 I have at clipping 37V about 171W
on a load of 4 35V about 306W. It seems to me that by raising the bias of the mosfets they start to raise the temperature and consequently increase the rds on. This could cause the MJE350 driver to fail and no longer be sufficient to drive the six mosfets. If this is the case, I have two options. First option is to leave the mosfets at 70V, which becomes 68V at work, and increase the vas and driver to 75V regulated.
Second option is to replace the MJE350 with a more powerful one.
Do you have any suggestions or have you already gone through this experience.
Thanks to all those who want to leave a contribution.
GIUBOS

Hello,

I am slowly gathering parts for my first build: the Tubelabs SSE. The board has many options and flexibility and I intend to use it. General outline below:

• B+ voltage of 450V (use as many different types of tubes as possible)
• 8 Ohm speakers
• Triode / UL switch
• Cathode feedback switch
• Rectifier switch
• Volume pot
• Switchable cathode bias resistors (680 Ohm, switching 680-750-910-
1K2-1K5-3K3 parallel with that)
• Considering a measurement point for tube current

Parts mainly as supplied in the parts list on the Tubelabs website, with addition of:
• C-14X choke
• Auxillary power supply cap
• Auricaps for C11 / C21
• CL1440 inrush limiter
• 2x 1N4007

For the power transformer I’m thinking of Edcor XPWR059 and output transformers Edcor CXSE25-8-5. Unfortunately, on my side of the pond (Europe, GER/NL/NOR) these things cost an arm and a leg. Any suggestions on:

• More affordable transformers
• Toroidal or “conventional” ?

And obviously, any pointers on making this plan a success are utmost welcome😀!

Cheers, Bill

Went to use my good old Tektronix 2335. Chanel A is dead. Reads about 100th and fades. Any ideas, or is it just time to find another?

Sorry if I am spamming but i couldn't find the right thread.

I am very new to building DACs so when i saw that someone on my local market was selling a knock-off soekris DAC ( the dac accepts 4-wire I2S and is supposed to support sampling rates up to 24 bit PCM384KHZ) I thought to myself why not just give it a shot.
First off I tested it with a RPI 3b+ running Moode. I set it up to work as with Soerkis dam1021. It worked just fine so i decided to order an Amanero of audiophonics and some female to female I2S cables to set it up as a USB input.

That's where the troubles began. I am not able to get anything but the static/ white noise out of the DAC. I am pretty sure i hooked it up correctly.

GND out of amanero >> GND on dac
FSCLK out of amanero >> LRCK on dac
BCLK out of amanero >> BCK on dac
DATA out of amanero >> DATA on dac

I tried installing ASIO4all driver and still was not able to get anything out of the Amanero board.
I have seen that you are able to program the amanero but frankly speaking I am not so successful with it. And that's the main reason I am seeking help. Would appreciate if someone will be willing to share some knowledge and educate me.

Thanks in advance!

**EDIT** I forgot to add that the static / noise is only present while anything is playing on the pc. The moment the playback stops so does the static.

Hi, I already put this summer a similar ad and I did end up buying my first MM pre amp which plays very nicely, but am looking to go a higher end and if possible also allow for MC cartridge (which I am thinking of getting next year).

So again if you have anything you want to sell please PM me.

I’m slowly working on a Carver TFM-25 with a blown right channel, working through the schematic and trying to educate myself on the 3-rail system, and have a few questions. Repairing this amp will be mostly an educational experience, and only used for a bedroom stereo. Sonic perfection would be nice to have, but it’s not fully required.

I have built amplifiers off and on since the days of the SWTP Plastic Tiger and Tiger .01, even recently repaired a couple of Adcom 555’s, but I lack the component level skills of knowing what is a good or bad transistor substitution.

I have found one of 2SA1302’s to be open, but due to the number of counterfeits on the market, I would rather replace the PNP/NPN pair with the Hitachi 2SA1943/2SC5200 from Digikey instead. Will this work okay? Should I just get a few of each, match them, and replace them all?

My father bought this amp brand new in 1991 and it worked well until a few of years ago, when he lost the right channel. A thorough cleaning and visual inspection shows the amp in excellent shape, no brown areas on the PCB, no obvious blown or burnt components, and only a few suspect solder joints, which I touched up. The funny thing, is the left heatsink has 4-2SA1302, 1-2SA1301, 4-2SC3281, 1-2SC3280, the right heatsink has 5-2SA1302, 4-2SC3281 and 1-2SC3280. Per the schematic, the left side should be the same as the right side (the correct layout) so it looks like a factory error. From the specs, and to my untrained eye, it looks like the 2SC3281 is just a more robust version of the 2SC3280, but I’m not sure of what the sonic difference should be, or if any of the resistors should be changed for the difference in current between the 2. My question is, can I replace the 2SC1301/2SA3280 pair with the Hitachi 2SA1943/2SC5200 pair? Do I need to changes any resistors? Try to dig up matched 2SA2SC1301/2SA3280 pairs? Try a better substitution?

Last question, I usually make it a habit to change the drivers when I change any outputs, because they are cheap, and it’s cheap insurance. This amp uses 4 pairs of 2SA1370/2SC3467 as drivers and pre-drivers. Digikey doesn’t stock these, but places like B&D, Newark, MCM, etc do. I’m not sure which distributor to trust, or if I should try a possible better substitution from another reliable source.

Sorry for the long winded post, and thanks for your time!

Win

one of the most useful tools I have is my fingernail but I would like something more professional.
as an example, if there are some paint spots or other gook on the front panel of a receiver I have found the best way to remove them is my fingernail

it removes them without damaging the front panel itself, metal tools will certainly remove the undesired junk, but the nice front panel is going to be scratched or gouged

I really want something easier to use
I have tried a couple wood and plastic "tools" but none of them come even close to doing the job
Is there something that people can recommend that I have not tried (which are only a few items I had lying around)

Hello lovely people, just wondering if anyone can help me, I have a meridian 557 with rising dc voltage on left output, (speaker terminals )all electrolytics have been replaced, apart from main filter capacitors. output and driver transistors test ok as do the emitter resistors, it shuts down when it reaches 5v and climbs steady from 0. Nothing seems to be getting hot. I've had a run through with the multimeter and nothing jumps out as obvious when dead testing.
I know I need to start measuring voltages now and am gonna start with the 15v regulators.
Looking to learn and hopefully fix this, any help/advice great fully received 👍

I am looking to buy a new/used mint pairs:


1. Dayton RS28F-4 or RS28A-4 pair tweeters.
2. Dayton RSS210HO-4 pair subwoofers

If you have a pair laying around, please let me know. Paypal ready. Thanks!
USA or EU

Laser adjustment on Teac VRDS-10 - how?

Hi all,
I am trying to adjust the laser on the Teac VRDS-10.

So, since I am new to electronics, and I haven't done it before, I am studying the Teac VRDS-10 Service Manual.

Some of it is pretty easy to understand and I have done some tests, and a single adjustment just using my Fluke 179.

There are however some problems as I also need to connect an oscilloscope and adjust accordingly to how the waveform looks.

On the first picture one can see the test points and trimmers.

My first question:
the manual says measure an offset millivolt value of no higher than 50mV on test point 3. There is only one pin at Tp3, so I don't know how to perform that?
And I don't understand the term offset voltage?

Secondly, I also have to connect an oscilloscope plus an external tonegenerator to the player plus a single 100kOhm resistor. See picture.
While I think that the output wires from the tone generator is + and - (gnd) and the + goes to the scope and continues via the 100kOhm resistor to the test point 1, pin 1, and the - (gnd) from the tonegenerator goes from that to the scope ch1, and continue to Test point 1, pin g (gnd), I don't understand the third wire that seems to go from somewhere on the scope to the Test Point 1, pin 2. Is that the output from the cd-player on to the scope? And is that connected to what?

I am trying to learn using the scope Rigol DS1104Z Plus.

I hope you will enlighten me on the matter, so I can perform a full set of laser set up. It is MOST appreciated.

Kind regards,
SFC1000.

Hi, I own a Azur 540A and I was using a subwoofer with it via the Pre out. My son pulled out the Rca going from the pre to the Sub and I believe it wa sshorting out possibly. All of a sudden there was smoke coming from unit. I opened it up and noticed that u5 chip is totally fried and when turning it on the unit goes into protection mode and it sounds like the volume motor is moving. Anyone know what function that chip has and also what can i do to repair this.now. This is second Cambridge Amp to die on me. Both times from stupid mistakes.

I greet with great pleasure

I have a 1980 sony amplifier that uses NJM4560D as flat amplifier in tone section, i would like to upgrading performance like S/N, slew rate, THD. I think to use NJM4580D to replace NJM4560D

I have a question: can i use NJM4580D as direct upgrading of NJM4560D?

I only seek a direct replacement without modifying the circuit, I just want to desolder the NJM4560D chip and put in place the upgraded Op-amp.

I would greatly appreciate your comments regarding my question

Thank you.

Moderation edit: TLDR, start at post #10.
This began as a speaker thread asking to attenuate the speakers to reduce hum, and has now become an amp noise thread.
----------

So I deceided to go back to trying active again. I'm trying to connect a very powerful 6 channel amplifier I have
directly to speakers, using an active crossover and bypassing the internal crossovers. The amps are 6 - 500asp

Icepower modules. Running this much power to a tweeter
does make me a tad nervous. Also, there's some hiss and hum
I'd like to attenuate. I'd be using the 6 channel dac as a volume control.

I called Solen about whether to use an lpad or resistors and the
tech advised me to use resistors instead to pad the drivers down
using one series and one parallel resistor per driver.

So being that its a 3 way I'm thinking 9 db for the tweeter, 6db for the
mid and 3 db for the woofer. I think the tweeter is around 91db efficient,
the mid around 88 and the woofer 85 db.

My question is two fold, firstly does the resistor wattage in this case
matter that much? The thing is these amps are capable of sending
out 250 watts each, I know the drivers wont receive anywhere near
that being that I dont listen that loud and the signal will be crossed
at 450 and 2750hz. What is the minimum wattage resistor you would
use in this case?

For the parallel resistor can I just run it along the neg and pos binding
posts and then one from the pos inside the speaker?

Using this chart from Solen I've determined the following values: Solen Electronique Inc. | Values for L-Pads

tweeter - 9db attenuation: series resistor 3.9ohm parallel 3.3ohm
mid - 6db attenuation: series resistor 3.0ohm parallel 6.2ohm
woofer - 3db attenuation: series resistor 1.8ohm parallel 15ohm

I was thinking about using these 16watt mill spec resistors:
Solen Electronique Inc. | Product categories | AchrOhmiC MIL Spec Resistors

Ive attached a pic of the speaker impedance chart. Should I be ok with this?

OK on this little A12 amp, I am measuring a 20:1 turn ratio on the 8ohm tap and that = 3.2K primary. On the UL/screen tap I am seeing a 10:1 turn ratio on the 8ohm tap and that would be 800ohm.

Am I right in assuming then this is a 25% UL tap? Or is that a 50% tap. I get the 3.2K part but not sure how the UL/screen tap ratio part works.

I did just measure a known 3.5K into 8 ohm 40% tap SEUL transformer and got 21:1 on the primary and 8:1 on the UL so sounds like this other A12 one is a 50% tap?

This also now has me wondering, is this a PP OT they put into a SE amp? That would explain a lot.

Hello every one , great forum with usefull info. But cant find anything of my topic , i search mixing mixer summing and other key word, but is look like forum give me the same results.
My problem is that i want to conect 6 line inputs before the amplifter (yamaha 500 ): Smart tv true some chines dac, amazon alexa , pc with additional sound Idj card , 2 microfone karaoke set, bluetooth 4,2 reciver and maybe one extra for any case.
i just fin my shop car list form local el parts website to build this:
Universal Preamp/ Mixer (Part 2) figure 1 with ne5532 op amp (only that have in shop)
with this power suply:
https://www.circuitlib.com/images/schematics/power_supply/Symmetrical_power_supply.jpg
using it this traff BV EI 303 2039 HAHN - Transformer: encapsulated | 1.9VA; 230VAC; 18V; 18V; 52mA; 52mA; 81g; BVEI3032039 | TME - Electronic components BVEI3032039
price of all that is hit 35 euro without calculating the box.
in same time i see this device:
AIYIMA 6 Ways Stereo Mixer Audio Distributor Mixing Board With Independent Volume Control DC5 24V 1PC 6 Inputs 1 Output|Amplifier| - AliExpress
without need of two line supply and still give 2 times gain on 1/3 of the price !
In fact i dosent need any amplification of the sound , i never use the yamaha amp on maximum. I just need easy and sure way to connect and switch all the inputs to the amplifter.

my question are:
1. Did i over kill the situation or is normal way to be done?
2. DIY or BUY - to continue with my DIY project or better to buy that aliexpres thing 🙂
3. How i say i dont need amplification with sure , if need something it be:
- Control the inputst true I/O pins on esp8266 maybe with paralel relays
- led indication when one line is active. (turn on if have signal) it e so usefull for troubleshooting and seting up.
4. Or to hack the yamaha amp and to put kakaoke input behind all line IN ? becouse actialy only this need to be mix, all other now is easy to switch true the buttons of the amp inputs.

Please see attached. I've long wondered about their purpose.

Thanks, Steve

Hi,

I am debugging my ML332 with noise issue. I have the amplifier driven by a 1KHz 50mV sinusoidal. The final output to the speaker is fine. I probed around the voltage gain board using an oscilloscope with AC coupled, and see no signal at the 1st differential stage outputs, shown by the red dots on the picture. I suspected the input impedance of 10MOhm is low, loading the output. Even I changed the probe to 100x with 100MOhm input impedance, I still cannot see any 1KHz signal at the red dot locations at the low setting of 10mV/grid, while the 1KHz tone is clearly playing at the speakers. Anyone has an idea and experience on probing the ML differential outputs? I am puzzled.


Thanks,
cfy30

I made Hawksford output error correction and have very low distortion. But I'm not sure how to compensate bias current? I think error correction's transistors (Q9 and Q10) must be mount to same heat sink of output transistors (Q13-Q18) and driver transistors (Q11 and Q12).

How do you think?

I need help looking for part numbers for the plug connectors on the Precision Power, Power Class series amplifiers. I'm looking for the 2 pin, the 4 pin and the 5 pin connectors. I tired Digikey and Mouser but there so many variaties and I ran out of names types of the connectors to search any more.
Can you help?
Thanks for looking!

I am requesting recommendations for a program source (a downloadable .mp4 or .wav or a Spotify album) that plays random noise that I can play thru my system, and then use a phone app spectrum analyzer to walk around and see where room resonant standing wave peaks or nulls may exist.

Yes, this is a very crude, non-calibrated method, but I am not ready to invest a lot of $$ now.

The random noise apps that I find on AppleMusic or the Android PlayStore are intended for background noise to aid mental concentration or sleep relaxation. The envelope of the spectral content varies over time to simulate ocean waves or wind or a waterfall, so that is not good for my purpose. I want noise that has a steady spectral density.

And while I am asking, what can you recommend for spectral analyzer apps? Ideally, 1/3 octave resolution or tighter, with an averaging function to smooth out those random peaks/dips in the source content.

Thanks in advance!

Hi, this is Ale from Italy, any answer will be really appreciated.

I own a NAD 3020e (it's been like 12 years since I purchased it on eBay from the UK.. good old ebay times, when buy it now wasn't that commonplace), and it works perfectly. Nonetheess I miss something... a remote control, just for the volume!

I can solder and I am well experienced in DIY projects, even though not in electronics. I have found the schematics for my NAD, and it says the volume potentiometer (which is knurled) is a 50kbx2 (which I admit I don't really know what the meaning is).

Anyway, I'd like to swap it for a motorized one, with a remote control. A good start would be knowing which of the many on ebay or amazon is the right one. Then some soldering advice or how to make it work would be best.

Ciao and thanks,
Alessandro.

hi all,

does anyone have an opinion on the following universal players as a stand alone CD player?

- DV-09
- DV-79avi
- BDP-09FD

wondering how they would stack up against my current ancient digital front end. Theta DSPro GEN III DAC, Pioneer Elite CLD-79 laserdisc player (as a transport).

the reason for all this is i've noticed my system started to sound more fatiguing. almost to the point of thinking "is there something wrong with the tweeters in my Yamaha NS-1000M?"

out of curiosity, i hooked up the CLD-79 direct to the preamp, no theta DAC (never tried this before). sounded MUCH more relaxing! who knows, maybe it's time for the theta to be recapped. not sure if i wanna go down that road.

the CLD-79 uses 1-bit DACs and legato link DSP... so that's gonna take the edge off anyway.

anywho, wondering if the above choices would wax the floor with the theta, even if it was in tip top condition.

i REALLY want a PD-93 or PD-91, but those things go for mucho dinero.

thoughts?

Regards,
Robby

Did you ever see that Louis CK bit where he’s laughing at people on the airplane who are pissed because their phone doesn’t work? “You are flying in the sky, 30,000 feet in the air, at 500 mph, in a warm comfortable chair, and you are complaining because your PHONE isn’t working?”.. I love that routine. And that’s how I feel about what I am about to say. I am the guy with the phone. Without Papa and DIYaudio and you guys, there is no way I would even be contemplating building a high quality amp. Not in a million years. Yet here we are, and I’m complaining because it’s confusing and I don’t know which paths to take.

So, with that prelude, I have a modest proposal. It would be nice if there was a stepping stone up from the ACA; a complete, step-by-step plan, overly detailed instructions, complete BOM, maybe even a “project” on Mouser, etc. with everything matching perfectly so that a person, with a little common sense but with no confidence or understanding of what they are doing, could simply follow all the steps and come up with something First Watt level (F5, etc) that works. Pick the case, the power supply, the components, the boards, the complete parts list, and go. No customization options, no choices or decisions to make, just a functional, world-class amp in a box.

I know that is the point of the ACA, but F5 is a whole different level. I don’t know what a snubber is. I have no idea how to size my capacitors. CCLCCLCCR?? Quasimodo? Bridge or discrete diodes? The ACA is a tremendous success, and a model for how my proposal should work, maybe without the full kits, just full instructions and tools. The leap from ACA to Aleph J, as it stands now, is daunting. I realize this is asking a lot of volunteers who have already given way more than they got to get us to the point we are, but maybe this might be considered as a next step. Presumably, you volunteers do what you do here because you enjoy it and you want to help people and expand the community. I think this option I’m describing might be a good gateway drug for many people to the next levels of involvement.

Personally, I’ve decided on an Aleph J as my next amp project. I have ordered the boards, case, many of the parts, and I’m sure, eventually, I will finish it and have a deep sense of satisfaction for how far I have come and how much I’ve learned. “Gotta burn to learn”, etc. But, I’m frustrated and often overwhelmed at this point. Hundreds of pages of threads, poor recollection of where the key bits are, etc. And I have a decent technical background, including a degree in engineering.

What I really want is to build the amp, relatively quickly and painlessly, with my coach, the build guide (videos?), telling me EXACTLY what to do next, and as importantly, why I’m doing it. This subassembly is here because it is needed to do xxx. These parts make up the subassembly and they do yyy then zzz. Etc. I wouldn’t need to understand it all, but seeing, touching, building, etc will certainly give me a feel for what’s going on.

If you are into modding, tweaking, improving, experimenting, the current system is fantastic. So much to learn, so many things to play with. I want to be at your level, and some day I possibly will. But, the steps are very high from one level to the next. A half-way step might make it easier for more people to make it to your level. I get the sense that many people who are proficient audio modders feel that reading through all the threads is sort of a rite of passage, just something you need to do, to progress. I agree that it may be the only way to do it now, but it is not a guarantee of success, and it is probably not the best way to get people up to speed. My proposal, I believe, will get more people farther along quicker and with less frustration. Some day, hopefully, I will be knowledgeable and skilled enough that I can contribute to such efforts.

Hey Guys,

Long time lurker, first time poster 😉

Im currently looking at building my own clean power amp for my line 6 helix preamp to run though my cabinet. as im working through what i'll do i was wondering if i could have some opinions on the power supply.

I have attached a block diagram and table of my ideas and the 4 voltages and their uses.

Is the best way to achieve this to using a SMPS of 24v regulated straight from the power supply and using a voltage divider to get the 12v bias and then getting the 9v and 4.5v bias by regulating part of the 24v down to 9v and then using another voltage divider? Below is a block diagram of my thoughts.

Would this cause issues and is there a better way to achieve this? Sorry if this has been previously covered.

Hello everybody I am now selling my completed EC 7293 amp for $1800+ shipping.

I would like to say that the fit and finish on the casing itself is definitely DIY looking, but other than that the electronics of this amp have been put together with care.
This amp has Clarity Caps as input, Nichicon ES as the feedback caps, Furitech FL-09R IEC, Tube connectors, DH Lab's copper RCA. The total build without any tools I bought to complete this was $1010.
When someone buys this I plan on upgrading the feedback caps to Audio Note as people in this forum seem to think they are a lot better than the Nichicon ES.

I am only selling this as I want to build this again but would like to make a custom cnc case and use even better components.
if you would like pictures from all the angles of this case to see the condition please let me know.

Here is a link to the EC 7203 forum: https://www.diyaudio.com/forums/gro...d-frontend-60-120w-8-4ohm-42.html#post6759247

Willing to negotiate
Thank You

How would a few microwave oven transformers due for output transformers? They have a independence of 2200 ohms with a 8 ohm load. They could do as HV chokes also?

For Sale: 10 pieces of PMI OP275GP. These were purchased for a long abandoned project and are unused. Chips date from 1994.

$2.25 each + shipping from USA. $20 + shipping for all 10.
You choose shipping method. Payment via Paypal or Venmo.

Here is a link to the current data sheet:
[wiki=https://www.analog.com/media/en/technical-documentation/data-sheets/OP275.pdf]%[/wiki]

900W Class H PRO Power Amplifier.

Hi all!
This is not my first amp, but it's a first two-rail amp in my series called "Nataly".
Specs:
Nominal power - more that 900W, 4Ohms
THD on all frequency response - less 0,03%
THD on 1kHz - less 0,005%
This amplifier was made and discussed on Russian forum: V.2013 Äâóõýòàæíûé PRO-óñèëèòåëü â êëàññå Í
Project homepage (in Russian language) - ????????? ???????? Nataly - ????? ?? ????????????????
With respect from Russia
Vadim Mogilniy.
My nick on Russian Sound forums - Waso.

Hi

I would be very grateful for recommendations for a DIY integrated amp ...

My system is (was)...

• Source – NAS to Raspberry Pi 2 (running Moode Audio) + Audiphonics I-Sabre DAC ES9023 V2 TCXO I2S DAC with linear power supply
• Amplifier - Linn Classik (original version)
• Speakers - Quad 11L2 (6 Ohm, 86dB sensitivity, 30-150 Watt recommended)

..and it sounded lovely to me, but the Classik has developed a known recurring fault (IIC). This cost me £150 to fix last time and I don’t want to keep flogging a dead horse and since I'm only now using the Classik as an amp, I thought I might try a DIY integrated amp instead.

I would like;

• sound quality to be (at least) as good as the Classik. It’s power was plenty (75Wpc into 4 ohms).
• remote volume & input selection.
• A kit with most components supplied, or better still wire-together modules for speed (I have a 5 ½ year old child!).

Any suggestions would be very welcome.

The 11.11.21 the founder of Hypex and long time member of DIYaudio past away. Only 57 years old. I would like to dedicade this thread to him. He did encurage a lot of people to get in to DIY. My self included (after a decade out of the game). The work Jan-peter and the rest of the team at hypex has done can never be repaid. I hope hypex will still go strong and continue the god work.
We will miss you alot. And condolances to his family, friends and coworkers.
Rest in peace.

I have a working pair of Acoustat 2+2 for sale.
The speaker panels have been changed. The fiberboard frames have been replaced with steel, and the base has been replaced with oak.
Magical 3 dimensional sound, especially if, like me you can keep them more than 5 feet from the front wall. I used to listen to these at 100 dB ( peaks )
(I also use a Vandersteen subwoofer)
That's them behind my McIntosh speakers.
Pick up in central iowa
OR
I will sell the electronics/transformer boxes by themselves. MK121C with red medallion and C.
The circuit board was modified by me 15 yrs ago by reading threads here to change the resistors and diodes (?).To get the bias voltage back up to snuff.
Speakers entirely: $400
Electronics only $350 + $75 shipping unless you live reeeeeel far away, then I'll have to figure that out and get back to you

Thanks
Paul

Most Greedy Greedy Greedy Boy (of them all)

Yup , that one would be Me , Mighty Moi , ZM

What’s the Catch ?
Nothing …. except here’s the story ……



Culprit : I was constantly bugging Papa about mostly everything , squeezing both question and answer of 42 ….

Consequence : so he in one moment (certainly desperate move ) came to idea that bribe is the way to cope with me ……..


(Fact: Papa is naive ; Do not tell him that simple e-mail addy block is more than sufficient to solve all his ZM related troubles…….. though if he really start using that , we’ll have mass suicide of DiyA Papaland members ……. sometimes I have an impression that e-mail traffic to Pa is almost big as regular posting on forum )


So – he asked me what do I want , from pretty extensive list of things , he’s working on lately;


As usual , I said – nuttin’ , frankly not needing anything , being 2 (3, 4, 5) years late in things obligated (from various reasons) to build for my self …..
But – after repeated reading of his proposition , greediness started getting better of me , and I asked him for few more words about DEFiSIT ; when he replied , I instantly had impression of (my absolutely fave) M2 , with heavy twist(s)
so ……..
now – few pics from recent BAF....... Papalecture , DEFiSIT simple , DEFiSIT no values , Real MCKay one and two , little more detailed schm.

I have seen a similar question on SMPS dual rail PS, but my query is related to a dual rail linear PS.
Can I use just the positive rail and leave the negative rail open? The load would be a class A amp.
Thanks

Hi. For sale an almost complete kit to build the Crystal JFET Phono, full dual mono from RJM. The kit includes the two PCB, matched J113 JFET from RJM, and the rest of the needed parts, all the SS parts needed, MF resistors, caps, all good quality from Nichicon, Wima, etc... You'll also get my detailled BOM and the rest of the technical info to complete the project, except to large film output coupling cap...

I'll even inclded a nice double rca Jack, gold plated (Recycled but just as good). You just need to add an enclosure, and the power supply to have a complete great phono preamp. The kit is small and will fit into a small box for shipping, so shipping cost will be low... Too many projects, this one need to go. The first image is what included, the others images are mostly just for reference, and show what the preamp can be. My kit is not assembled, just the PCB and parts...

In these days of parts shortage it is great to have a complete kit to start with...

For info see: RJM Audio Crystal P jfet phono preamplifier | development thread

I'm asking 75$ (+shipping) for the kit, less than the parts cost...

Hi. For sale Input and switch boards for Soekris DAM1021 DAC, I think it is version 1.0, all assembled, except the leds on the switch pcb, costed me 40$ with all the parts... Just missing the Amanero USB interface (not included)

asking 25U$ o.b.o + shipping

Thanks
SB

I have a faulty NAD S300 int amp which goes into protection mode when it is switched on. The LED on the front panel is flashing.

I have found a few people who have reported the same problem with this amp. Can someone tell me what the problem is and how to fix it? Thanks.

Hi
I have a couple of questions.
I have gone from a 2 stage to a 3 stage design.

My old 2 stage design was a 6J5/300B design, which had a lovely tone, but I felt it needed a little more gain and that as a result it lost some bottom end control.

So I have gone to a Morrison 6SN7/300B design, and this has more control and WAY more gain. But despite star earth, separate signal and chassis earths, and shielded input there is quite a lot of hum, not with the input grounded, but when I turn up the 100k input pot the hum increases quite markedly.
I am sure that this is common issue with a common cause but I couldn't search it (as every thread has 'hum' in 🙂). So any pointers gratefully received.

The second question is, how to lower the gain of the morrison circuit? Do I lower the anode resistor or raise the cathode resistor of the first triode? If I can really lower the hum then I may not need this, but I am up to VERY loud at 1/2 way on the pot so dont need all the gain.


Huge thank yous for your time, and keep well!

Great set of 4 - 16 ohm dual voice coils. Wire them how you want em. I used them in the lower set of Super V's, and may no longer have use for them. Perfect shape. Shipping is optional, but would prefer pick up in 54650 area of WI.

Acoustic Elegance Dipole12 woofer for Open Baffle Bass


Jon

I have a Rogers Cadet III Integrated Amplifier that I would like to sell.

It is completely original as supplied by Rogers back in the 1960's.

It comes with the gold PU Cartridge.

It had one owner from new who bought it from the local HiFi shop in Bedford, England. I purchased it from them. I have no wooden case (sleeve) as it was integrated into another piece of furniture.

I have all the original Rogers Documentation including Owners Manual, Rogers Brochure, Copies of reviews from 1960's publications. Documentation includes Circuit Diagram and a list of all the components and their values.

Please contact me if you are interested in purchasing. I am located in Devon, England.
.

Looking for JanTx 2N2369A NPN NOS
large or small quantity. PM if you have any for sale or a source.
TIA

Have anyone experimented with a phase shield on a 5-6" midwoofer? I'm getting this driver 6″ SB17NBAC35-4 / Aluminum - Sbacoustics soon.. If I could knock down the on axis frequency peaks from 4.5kHz and up, this driver would be extremely good. I want it to match the 30degree response somewhat out to 7kHz. It would then be a lot easier to implement with a 2. order lowpass filter.
A 19mm shield would be 1/4 of the wavelength of 4.5kHz so it should cause some diffraction and effect the higher frequencies. If anyone have links to similiar products or experiments that would be great! I have REW and umic-1 so if this works in theory I could make some different sized shields and do some measurements.

Recently I watched a video or I should say 15 or so parts of someone that clearly had no mechanical aptitude trying to show their expertise in the construction of a cheap ebay knock off amplifier. To make matters worse the video maker purchased "Boutique" parts in an attempt to make something that was clearly inferior into something somewhat usable and claiming they could clearly hear the difference in the performance over run of the mill ordinary parts.

I'm a firm believer in a saying " You can polish a turn and it will still be a turd."
I cringed when I watched the person use a vernier caliper's jaw to scribe a line on a hideous rectangular shaped chassis that might have been suitable sitting on the lower unseen shelf in ones garage.

Its clear in my mind the extremes one would go to obtain some type of following and lets not forget that youtube check.

Hello,

I'm an long time audio enthousiast, so i've come across this forum so many time. Now it's time to register…
\
My main interests are around amplifiers (repairing, playing with cheap class D), speaker (measurement, exciter, diy), diy equipment...

I'm not really a big forum writer, more a reader, maybe things will change now that I'm registered.

See you.

Hi all,

I'm so glad I found this forum. Its hard to find communities these days that are filled with people who are passionate about their topic or hobby and successfully managed to keep out the spam and chaff.

I have had several different careers, but the relevant ones for here are my current ones. I am an electrician by day, and I run a design/fab furniture shop in my afternoons (I also have 2 young kids, so they get my nights).

I have several goals for joining up here, but I'd love to start out by building a nice setup for my workshop music. As always happens, I'm sure I'll dive in just deep enough to want to make different and more advanced stuff after I get my feet wet.

Just so I can point back to here in future threads, I have a 3'x3' spindle-powered CNC (and a 4'x8' soon, hopefully), a 3D printer, a decent grasp on Fusion 360, a full compliment of woodworking tools, and a nice little bench power/soldering station.

I look forward to picking your collective brain to get some cool things built and I hope to gain enough experience to be able to contribute my own advice in due time.

Found web site and want ask, have Realistic sta-2000D. Moved to paint now shuts down in 1 second. Is that a repair for me o audio shop? If shop where is audio shop you recommend? Live near SC. OR NC., And do not want any of those NTC or ECG parts. Thanks in advance for your help and having a web site to help people like me.

When I'm bored I sometimes use the local channels' weather radar to wander the globe. While checking out Australia I zoomed in on this city ... Kalgoorlie.

Now being from the midwest (USA) I've seen some deep holes (iron mines) but the one @Kalgoorlie looks pretty deep. Got to ask anybody that lives around there ... how deep is that?

I have a left over analog board suited for the TDAI-2170 and TDAI-3400 with a nice AK5294A ADC on it. I didn't find a service manual online but it seems fairly easy to run it stand alone: I managed to select the inputs and the +6dB gain by writing from an MCU to the 74HC595 which is accessible through the multi pin connector.

The board expects 3 power supplies of (I believe) +12, -12 and +5 volts, but there is one thing I don't understand:

The relays have 12V printed on them and are directly supplied from the input voltage, so I don't think I should feed higher than 12V to the board. But there are two regulators in series on the board: a 78M09G and a 78M05G, generating the 5V needed for the AK5394A. But the 78M09G has 10.4V at it's input and 8.7V at it's output and the data sheet says drop out is 2V (the 8.7V go into the 78M05G which outputs 5V). What do you think?

Please could anybody who has a Lyngdorf measure the voltages on the pins shown in attached picture for me? That would be of great help! (The attached picture shows the motherboard inside the Lyngdorf with the multi pin connector where the ADC module connects to.)

Been living in France since mid 2009.after leaving Spain after 8 years. The Spanish word 'enchufargo' explains all, it means to be connected, I wasn't and if you aren't nothing is possible, 80% of all €500 notes were to be found in Spain, mainly in brown paper bags. No matter how much research you do you can't trust notarios/alcaldes/bankos/abogados/immobiliarios you can still end up having your house bulldozed and being fined an awful lot of money - so we left.

Would have bought land and built my own design house but health problems got in the way for the next 6 years. We will get our Residency papers soon removing any doubts about continuing to live in France.

I was all set on buying a plot of land with building consents but for some reason or other I happened to look at American motor homes and further 'fifth wheels and travel trailers'.

Why - there is land with building consents, around €30K and there are other plots of land which you can use for recreation - loisirs which is very cheap, €5-10K normally around 1000-1500 sq.m. There you can park a campervan etc. no problem but you cannot build a house.

I've read quite a bit on American sites about the good and bad points with motorhomes, fifth wheels and travel trailers. I've ruled out motor homes, so I'm only interested in fifth wheels and travel trailers.

Any Americans or Canadians with actual experience I would welcome real time info from.

A lot of problems can happen because of (a) being on the road and (b) from being left out in all weathers.

I would construct a reinforced concrete hard standing with a water proofing additive above the level of the ground and once sited would not be moved, that should take care of problems associated with being on the open road. I would also construct an insulated skirt to protect the underbody from corrosion. I believe that I can have a water supply connected as well and have a fosse septic. With a diesel generator that makes me pretty independent of Big Brother.

If I build a house then I have to pay the housing tax known as Tax foncier, this is creeping up with every year. Living in the either model avoids this tax and insurance is cheaper, much less chance of theft or damage with living full time in it.

Some well known names in the RV industry have a bad reputation and you can't trust user reviews supplied by the companies themselves because no way will a company publish stinking reviews of their companies products.

If anyone can direct me to good user forums I would be grateful.

Problems with buying American - 120V electrics and non existent servicing, though apparently this is a problem in the States as well.

Why buy American - 30ft + are hard to find in Europe and like so many other things Europe is far more expensive than the USA. There are many top of the range models with loads of features that are around $80-90K. Yes I know I would have to pay shipping and in France a TVA/sales tax of 20% but then I have a fully fitted home I can move into straight away. Very good insulation is another +. compared to an old French house where you swelter in the summer and freeze in the winter. New French houses are so noisy (construction materials) and they are obsessed with having tiled floors - no thank you.

The biggest negatives for me are the colour schemes of so many are very dark, not a good idea when living permanently in one and cookers are for me outdated when a quality multi-oven is so much better. A big shower is also a good idea. We don't need sleeping for 8, there are just the two of us and at our age we don't expect lots of visitors. a massive fridge is not a good idea rather a decent sized fridge and freezer.

So please direct me to good RV users forums and any other useful tips or suggestions - thank you

Hi guys!
Here I have the headphone amp schematic that came up with and I would like to get some tips from you or maybe even confirmation if you think that it should be a working circuit. As a preamp, I'm using 12AU7(ECC82) and as a output stage WCF with ECC88. It is meant to be able to drive 32 ohm headphones. The first half of the ECC82 acts as a volume control and then the signal goes to eq and then to the second half of ECC82. I really apreciate your help. Thanks.

Hello clever people,

I am looking at replacing some old caps in a vintage ARC preamp (still trying to loose a tiny residual hum) and thought I might see if the output caps coming from the cathode follower on the last valve might be part of the problem. This valve has an AC heater.

Anyway the question is related to the value of these. They are currently 10 uF and I have been told by a friend that if I have a high input impedance Power amplifier (which I do at 100K) then I could happily use 1 uF and they would probably sound better, and I could afford to fit in some more exotic caps too.

Is there a calculation that manages this relationship in any way? I found a website that calculated Impedance at frequency, based on capacitance; and obviously this changes at frequency, and also implies the lower value capacitor would seem to decrease the output at lower frequencies.

Any helpful knowledge here.

Circuit diagram attached.

Thanks!

Hi I currently own a Naksa 80 and I would like to know if it's worth it, to upgrade to the Saksa 85. What do you think?

Hello, I am looking for a pair of RS291.

They must mesure as new or very near .

Better from European Union for shipping .

Thank you in advance.

Hi,

Is there a way to use the analogue inputs on the DScope to record into an editing package such as Audicity / Reaper etc?

It's not been seeing a lot of use at the workshop, as we have other AAs from R+S, AP etc. I was thinking that were the DScope to work well as a soundcard, it could be useful to have in the home system - enabling one box to record, as well as run health checks on the home setup.

Thanks in advance.

Based on tracking pre-regulator circuit form National and this link I expect to achieve 1A regulated current. But in reality ripple voltage is around 0.2V RMS.
The voltage across second reg is around 2V and does not change if one or two red LEDs are connected between Vout2 and Vadj1.
Sims in LTspice are ok.