Hi, as the title explains, I made a terrible mistake. Is there any way to rescue the opamp? I contacted Sparkos, waiting for the answer from them as well.
There's an electricity sound coming from the speakers now btw.

I'm planning to build a pair of Scott Lindgren's Haruna speakers from frugal-horn.com, already have the FE166En but have a few questions, if anyone can advise.

1) The biggest problem is that I'm in Azerbaijan and have discovered that birch ply only seems to be available in 1.5m square sheets, whereas Haruna is 1.85m tall.

I suspect that issue is going to force me to use MDF. But I wonder if it might be a worthwhile "compensation" to increase the side panels from 19mm to 25mm thick? They will be quite a bit heavier but that's only really a problem during the build.

We do have businesses here that cut MDF to size, so that might actually make the project much easier - it can also come with various finishes, but then I couldn't use a nail gun to fix the internals in place, which is what I did with my Dallas 2. Though I could also veneer the outside afterwards.

2) The instruction says "you may replace the stacked corner deflectors with a single angled piece". If I used an angled piece I would then create a hole that needed to be filled with sand etc. so that actually seems to be a disadvantage. But is there any technical preference one way or the other of a step vs. a smooth surface?

3) The default damping is "line 5 faces of the driver chamber with 1/2" material...ensuring the throat remains clear" - so this seems to mean that the 6th side, with no damping, is the back side of the baffle?

4) In my Dallas 2s I lined the driver chamber with 3mm felt, using a spray glue, but it made a helluva mess as it was difficult to spray accurately. Maybe a liquid glue would have been better, but I was wondering if an alternative way would be to glue velcro in the driver chamber and use cut-to-size pieces of 12mm wool felt so that the damping was removable. This approach would also perhaps let me experiment with different materials in the future. Or is it important that the lining is hard-fixed to the cabinet over all its surface?

5) I've seen a couple of threads where the builders have added a supertweeter here and here, though they both seem to be using a Fostex FE168E Sigma. Is this something that I need to be considering for a standard FE166En? One puts the supertweeter inside the cabinet above the main driver, one hangs it off the side.

6) Last one for now, any thoughts as to whether an ACA Mini will work OK with these? I don't listen extremely load, but do plan to put these in a large listening room.

Thanks!

I need new speakers, and really want to build something. I've been looking around and fell in love with the Mezzo Calpamos. It's beautiful, a little different, and seems like it would excel at HT and music. It's a little big (but in some dimensions smaller than my magnepan mmg) but I think I might be able to talk the wife into it. Then, I realized I was looking at the price for one kit, and needing two I'm pretty sure it's out of budget.

I did more looking around and came across the Econowave and all it's iterations and thought I might be able to DIY a higher end econowave that is close for a lot less $$. However:

1. Most of the parts (especially waveguides) seem to be discontinued

2. Nobody seems to make them anymore. I don't know if that is because of question 1, or because something better came along, or if they weren't that good to begin with.

3. I wonder if econowaves "replaced" by designed that place normal tweeters in a waveguide that combined the best of both worlds?

Any thoughts? Thanks!

This is a question of general interest to those designing or modifying amplifiers, not just this one kit.

Is anyone but me concerned about running the 6P14 (or EL84) output tubes at ~350 volts in this amplifier? Isn't this voltage going to eat up the tubes very quickly? I don't want that. Schematic with suggested voltages from the building directions is attached.

The kit comes with what is labeled a "spare" zener diode that is 91 volts per the label instead of 100 volts like the others. That's in there to reduce the regulated screen voltage by 9 volts I assume? I am getting 316V on the regulated screen output when spec is 290V-305V.

Edit: I am well aware of the option of using a bucking transformer, and I am not interested in that solution for several reasons. As with most Chinese amplifiers, it is designed for 110VAC not the 121VAC that I have at my wall outlet.

Update: installing the 91V zener diode to replace one of the 100V zener diodes produced a perfect 297V on the regulated screen voltage.


6P14 tube - translated from actual Chinese specs (EL84 is similar):

Performance Parameters
Filament voltage (Uf)=6.3V
Filament current (If)=0.76A
Anode voltage (Ua) =256V
Anode current (Ia) = 48±8mA
Second gate voltage (Ug2) = 256V
Second gate current (Ig2) ≤7mA
Transconductance (S) ≥9mA/V

Limit Application Data
Maximum filament voltage (UFMax) =7V
Minimum filament voltage (Ufmin) =5.7V
Maximum anode voltage (Uamax) =300V
Maximum second gate voltage (Ug2max) = 300V
Maximum filament and cathode voltage (Ufkmax) ±100V
Maximum anode dissipation power (Pamax) = 12W
Maximum second pole dissipated power (Pg2max) = 2W
Maximum cathode current (Ikmax) = 65mA
Maximum first gate resistance (Rg1max) = 1Mohm

My mesuarament is correct? Example. At 1khz, 8 Ohm rezistor voltage is 50mV-150mV for normal too high volume. This means requared power is 0,15/8= 0,01875A. 0,01875*0,15=0,0028125w. Is this real? What i'am doing wrong? Driver ir FaitalPro 6rs140. This means enought power for one driver i some 1W? Can i use D class amplifier 2 x 2W? This is for active connection in 3way system. For each channel 2w enought? Watching at D class PAM8803 chip. Drivers is 10rs350, 6rs140, SB26STCN.
Link to system https://www.diyaudio.com/community/...italpro-6rs140-10rs350-need-some-help.393606/

Well, that was expensive. Sounds like it's gonna be worth it though.



The Ayre QB-9 Twenty is the latest of several upgrades made to this series over the years. New faceplate, new circuit, updated DAC chip. $3500 US retail.

The faceplate is very handsome in person by the way. It's aluminum, and from what I can guess the text and logo are left in polished mirror finish with the surrounding metal etched away to a matte grey. At back, there is a USB Type A input together with RCA and XLR line outputs, and jack for the AC power cable - no external power supply to fuss over! Apart from a set of dip switches in the back, there are no physical controls. The unit engages to display the sampling rate when the USB is connected to a computer and some audio software is run. The details of the sampling rate, etc., are set from the computer.

In terms of standard rack chassis sizes, it's roughly half width and a nominal height - compact but not tiny, it fits comfortably next to the Teac HA-501 shown in the photo above.

I appreciate that this DAC costs an order of magnitude more than what most people on this forum would likely consider paying for this functionality. It would be nice if it was possible to get this level of performance for $350, but in my experience, this is not possible. The QB-9/20 [as I will call it from here on in] is better than the Chord 2Qute (which is thin and sharp in comparison) and - while sharing some family characteristics - better than the Ayre Codex too (which is generally rougher). I can't comment on how it compares to similarly priced alternatives, nor could I even point to any. I didn't shop around, I just impulse-bought a used unit from a Japanese auction site. I heard enough to like in the Codex and had read the overwhelmingly positive reviews for the QB-9 series.

The first impression, listening via the HA-501 and Sennheiser HD600s, is of a) a low noise floor, b) a wide and detailed soundstage, and, c) an overly polite top end. Coming from the 2Qute, which has a lot of top-end sizzle, let's just say it took me a little while to re-adjust this new normal. By the second or third listening, though, I was satisfied that the Ayre wasn't playing the "rolled off treble = hi-fi" trick, it just wasn't adding splash, grit, or shine.

Where it gets interesting is that, after assuming the politeness was partly due to the warm balance of the headphone amp, I switched back to the Sapphire. Despite the anticipation that this would be the match made in heaven, I was disappointed to hear that the Sapphire brought a little metallic hardness to the treble, and added nothing much in the way of positives vs. the Teac. A little more experimentation revealed that the single-ended output from the QB-9/20 doesn't bring the same magic as the balanced XLR. The Teac, when connected via RCA, also sounded a little lackluster. Not bad by any measure, just - compared to what I had just experienced through the XLR cables - normal. That made the choice very simple: QB-9/20 / XLR / HA-501 / HD600. Together, this combo absolutely kills it.

A review of the Ayre Codex by Audiosciencereview

I bought an Ayre Codex for myself last year to find out how my own diy efforts, the Sapphire headphone amplifier, would compare to a serious high end product from a serious high end company. I had read the audiosciencereview report above before I decided to buy it, as well as many other online reviews. It did not dissuade me because I had faith in Ayre and their design philosophy. This is only reasonable: the Sapphire shares much of the same design principles of the Codex, and I know from experience that the measurements we make to test audio equipment rarely correlate with perceived sound quality. That the Codex posted some disturbing test scores did not bother me. Put it another way, I've had plenty of gear pass through here that won great praise for measurements but sounded like cr*p...

In the next few posts I'll be providing some annotations to the Codex review based on my own listening experiences, cross-referenced with my thoughts about how the Sapphire sounds in comparison. Expect some soapboxing about Ayre and the commercial hifi industry in general, together with come color commentary on the measurements-vs-listening-tests debate.

Stay tuned!

I decided to give the S.M.S.L. Sanskrit 6th a whirl recently to see how things stood on the cheap USB DAC front.
S.M.S.L. has long held my respect for trying hard to deliver high-quality audio at an extremely fair price. Just a quick look over the DAC's circuit board tells you that these are people who care about their work - from the etched S.M.S.L logo to the clean, logical parts layout. The build quality is apparent too in the simple, nicely finished case, which matches my Sapphire headphone amp (shown below) in "mini-me" style.

Part 1.

It's all "there", from the Cirrus Logic WM8740 DAC and NJM2114 opamp output with what looks like discrete transistor pair output buffers. The board generates 3.3 V, 5 V, and +/-12 V rails from the 9 V DC input. Other components include a 7805 voltage regulator, cmedia CS6631A USB audio processor, and Onsemi LC89091 receiver. A lot of stuff for the price. So it's a frustrating disappointment to have to report that it doesn't sound as good as I hoped. The sound is smooth, clean, and nicely detailed however. So, for the price, here again, one can't complain: it does what one might reasonably ask of it. It's hard to put one's finger on the source but musically, it fails to rise to the occasion. The sound is weak, feathery, light. Complex passages dissolve into incoherence. There is no power reserve. Perhaps due to the switching power supply whatever charge pump circuits are used to regenerate the internal voltage rails. Perhaps distortion from the transistor output stage, or insufficient filter capacitance near the op amp. These are just educated guesses on my part, but it does raise an interesting point: what does a DAC need to get truly high-end sound?

In Part 2. (coming soon), we'll take a look at exactly that.

Is there anywhere I can get free music to download for testing purposes? If this music is played back through a system and recorded, it would violate copyright to distribute the recording, even for demonstration purposes. This would be public domain music.

You Tube has some stuff but is not downloadable.

Hi everyone,

I'm redesigning a 5w LM1875 Guitar Power Amplifier that's powered by a Line 6 Helix (Line Level out) as the preamp. Is someone able to have a look over these images and let me know if there are any glaring errors they can see in either the PCB layout or the Schematics? The PSU board is powered by a LRS-36-100 SMPS.

Ive got a version of it already working, but this has had a few major changes from the first design, so before i send for it to be made,I thought I'd ask around get get a few sets of eyes looking over it.

ps. On the PSU board, I have both Audio and Power ground coming back to the same star grounding point on the pins. If that ok to do or should it be tackled differently?

Thanks!

This is a third stage of upgrade process. I think what pics are able to show the process as well as final result. On the final picture the 7 kilogramm platter consisted of 8 parts has been substituted with solid 12 kilogramm one. And yes, it changed the sound signature substancially.

Hi,

upon resurrecting a Pioneer PD 73, I've carefully completed the calibration process as described in the Service Manual (see previous post).
I've in order:

• set Tracking Offset to ~0V
• set Focus Offset to ~0V
• set RF Offset to ~100mV
• set the RF level to ~1.5V
• set the grating for largest T-Err signal after Null Point
• adjusted tracking balance after grating
• adjusted tangential and radial screws for optimal eye-pattern

This setup works perfectly with pristine CDs and CD-Rs but when the CD has scratches, black spots or anything far from a perfect surface, I get issues.
Let me explain:

• in Test mode, everything is read no skips, no jumps just music despite the surfaces defects
• in "normal" mode, on certain troubled tracks (those that are affected by defects) the player struggles to find the track start or skips seconds while reading the track.

I've tried to play with Tracking Gain and Focus Gain, but I had no good luck...(yet)

Any suggestion? Could it be that the capacitor around the RF Amp / Servo micro are dried and must be replaced?

Many thanks for any valuable suggestion.

PS... the little PD-7300 (which mounts the same identical optical unit PWY-1011) reads flawlessly even the worst disc.

Hello,

I've been playing with little PAM8403 amplifier and I have problem with a noise. I have to say I didn't analyze the spectrum in any software but by hearing it I would say it is something close to white noise. It doesn't change at all with turning the volume knob up or down or shorting the inputs. So I started looking on the internet for possible causes.

I found out that it could be the chip itself (PAM8403 doesn't have the best SNR value) but then I found some tests of different cheap boards with the same chip (not the PAM8403) and there were big differences between them in term of audible noise, similiar to what I'm hearing. And since then I wonder:

What causes this audible level of noise and can I get rid of it? It's a broad question, I know, sorry for that. I have two ideas on my mind - It's problem with filtering the power supply rails - or - The chip is causing this and those cheap chinese boards, whose tests I've seen, were using just bad clones of original chip.

I bet it's much more complicated than just this. So thank you very much for any useful informations or materials. I really appreciate it!

I signed up for the io group at https://groups.io/g/LTspice

But when I click on the links for the archives of the models below, the link just reverts back to the page above.
https://groups.io/g/LTspice/files/z_yahoo/all_files_z_yahoo.htm
https://groups.io/g/LTspice/files/z_groups.io/all_files_z_groups.io.htm

Every link in messages on that site just circles back to the home page.

Asking here just because I can't ask there. Tried another browser. What gives?

I'm just trying to find an LTSpice model of LF353, if there is a quicker way or someone has one.

So i want to build a smallish desktop speakers which will be used with a small subwoofer that i built, But cant decide what to do.
I was looking at markaudio chn-50 or chn-40 in a ported box.
So i wanted to ask:
1. Which one would be better for my application
2. Do they need some filtering to sound good
3. Are there any other recommendations for similar price (20€ per driver)

I'm looking to have a pair of Altec VOTT 817 cabinets built. Is there anyone in or around MN (I'm in the Twin Cities area) available to commission for the cabinet builds? Kindly reach out if so.

I got a surprise this morning touching one side of the microswitch power switch and chassis ground. I was under the assumption that a conventional power transformer offers isolation from shock hazard. If you measure between chassis ground and incoming ac there is 120vac potential. I would have thought the secondary of the transformer should have no reference to the primary. Will the center tap have potential in reference to the primary?

Picture attached showing the 2 points.

Thanks all

RRubycon Black Gate capacitor 3300/16v
I bought it from a friend in Japan, only used it for a short time. perfect working condition, $130 for 1 pair of capacitors
i have 2 pairs
I live in Vietnam
Please contact me if you have any need
thank you

I have a Connex smps800re that outputs +/-65v.
I want to build a 6 ch amp with it to power some active speakers.
I don't need huge power, 60wpc 8ohm is plenty, maybe 150w at 4ohm for the bass.
Any ideas? I have seen the cheapo irs2092 units but I don't have much faith in the quality, any other options out there?

Hi all
I'm a newbie connecting a car amp, and, Youtubing my way through this, it seems to be standard practice to power an amp straight from the battery inserting an inline fuse near the battery. I have wired mine in this way, but I'm just checking this isn't exposing the amp to fluctuations, transients etc from around the battery. What protection and filtering should it have?

The amp has some inbuilt protection...
Attached is an image of the components the amp has at the power inputs...
It's got 4 SMD caps, a ferrite core inductor, plus a Varistor (S14K14)
[From datasheet: B72214S0140K101 - VRMS=14V, VDC=18V, imax=1000A, Wmax=4.0J, Pmax=0.10W]
Is this reasonable surge protection (and noise suppression) etc to run it straight from the battery? Or should there be further protection and filtering etc? I have no idea whether the vehicle this amp came from supplied it with prior filtered or regulated power. The amp is a Volvo #30752259 (PA-200) 4x50W RMS out of a circa-2006 Volvo V70.

I have an LC power supply filter unit from another car stereo if that was useful or could be the basis of another power filter/regulator.

Thanks

I have a pair of SiderealKaps EGA7276-2 capacitors 5uF 200V. Are they OK for line level coupling capacitors?

Hi, I need advices trying to achieve this Reamp-Isolator box. The impedance matching is still a mystery for me, particularly from the preamp to the soundcard.

REAMP:
Soundcard (RME UFX+) -> Line Output / Balanced / 75 Ohm
to
Preamp (Steavens The Brick) -> Instr/Guitar / Unbalanced / HiZ

ISOLATOR:
Preamp -> env. 5Vrms / Unbalanced / 10 kOhm
to
Soundcard (RME UFX+) -> Line Balanced 12 kOhm

For the reamp, I don't need to mimic Guitar impedance. I just use the preamp as insert overdrive/distortion in my DAW.

Here is the schematic:

Interested in anything from pcb to fully built

I was a lover of SDTrans so I bought this to see how close it got. It doesn't get close to a tricked out 'trans but it has promise. Needs mods. Will include an SD card full of the well recorded shi-stuff vendors use at shows to make their systems sound good.

hi

I have bought Technics SU V4X amplifier - vintage.

Sounds OK, but I noticed that it runs quite hot even when I am listening it at low volume...

seems that it should be cooler... any experience with a/m

thanks in advance

I did this planset in 2018 and very few know about them so i thot i should post the plans.

Not really subWoofers, but this is the best section to put them in.

This woofer is really cheap and a really decent performer, but difficult to get outside North America. If you need some bass help, in something small that sounds good this may be something of interest.

http://www.planet10-hifi.com/downloads/SF-W14-woofers-120218.pdf

This is the same woofer we use in Tysen V2.

dave
.

In the past, quality defects were found in the LM4562/LME49720 op amps.

See TI forum entry:
https://e2e.ti.com/support/audio-gr...um/415907/lm4562-lme49720-low-frequency-noise

The production of the early years should now be sold out.
Does anyone know what the current situation is? Has the production process been improved in the meantime? Is the new production good quality?

Hey all!
I recently aquired a set of Dynaudio MSP 200's while roaming a second hand store. They looked questionable since the Woofers where swapped with a set of noname drivers with shot membranes but since the Cabinets and tweeters where flawless + price was irresistable i took them with me.
Now im trying to replace the Woofers with a worthy alternative. It would be nice to keep the looks original and use the original mounting holes, since the cabinets are in near mint condition.

-Since the cabinets are almost 40 years old i was wondering if it would be a good idea to change the capacitors of the crossovers too? If yes, are there any suggestions? PP, Elko? Specific Brands (Ideally with good availability in EU)?

-Is there a noticeable difference between a 24w100 and a 24w75? Spec wise they look quite similar. I would be able to aquire a set of 24w100 4 Ohm and possibly also 8ohm for a good price wich also leads to my next question:

-Lojzek mentioned the Volvo Dynaudio woofers as a possible replacement. For me they would be a neat replacement. The domes look similar, there are plenty around, the Price is reasonable and i think Lojzek mentioned the Mounting holes are also identical to the original 24w's. BUT they are all 4Ohm speakers. I was wondering if this would have a negative impact on the tweeters, crossover frequencys/ resistors or the general performance in any kind of way besides the higher load on the amp?

Looking forward to your Answers!

Hi!
Im looking for a Set of reasonably priced Dynaudio 24w75's for my MSP200 restoration project. In case you would consider a Sale, i'd be happy about a PM. Location: Germany.

I have had this since 2003 and have replaced batteries 3 times,I love this dac as it is easy to carry and test various systems,it also is very good on early edgy CDs
Where do I start to fix it, I do get some thumps when I switch it on and off
It's a kusunoki circuit,so maybe someone can fix it
Thanks

Is the schematic the same as those showing in post #12 under
https://www.diyaudio.com/community/threads/how-convert-creek-obh-8-to-mc-cartridges.151527/
with mentioned reducing of R12 ?

Thank you for an information.

Sorry we have been away for so long, as the UK's leading DIY mains cable supplier we now have over a dozen audiophile mains cables off the reel and a plethora of plugs and connectors for you to construct your own power cords. Please feel free to visit our new website at www.mcru.co.uk and mention diyAudio in the comments section when you order to be sent a free gift with your order.

Some of the brands of cables we stock off the reel.............

Belden - Acrolink - Furutech - Neotech - LAPP - Supra - Oyaide plus a huge selection of mains plugs and IEC connectors.

Hi folks, I'm currently cleaning up an old kenwood amp and this thing is brittle and difficult to work on and is only coming g apart this once! I'm after some expert advice on whether this phono stage can be improved? Maybe with the Riaa curve?

Hi folks

I have two of these marvelous Soncoz LA-QXD1 DACs available for sale. each complete with a low-noise power supply and set of (2) 18" XLR/TRS balanced cables. I used them in conjunction with a miniDSP nanoDIGI 2x8 SPDIF processor (also available for sale) for a mind-bending budget active crossover 2+ way speaker set.

They are in perfect condition, work flawlessly, and have the original firmware 2021.
Asking $175 shipped for each set, buy both sets for $330, or $425 with the miniDSP nanoDIGI.

Located in the San Francisco Bay Area if you want to test/pickup locally.

Thanks!
Robert

In the barn find of the day, picked up this Ampeg guitar amp. Was making a loud hum. Opened it up and found this exploded capacitor, which is nice to see, because you know the problem is going to be solved in two minutes and you don't have to hunt for it.







Looking at the amp, I wondered whether it would benefit from more modern transistors? I got this feedback about an Akai tape machine not long ago. It looks like it has BC169B, 2N4062 and 40623, 40625 transistors.

Helpfully, Ampeg glued the schematic to the bottom of the chassis, and labels everything on the circuit board -- gotta love that.

Relatedly, the hiss is very pronounced with volume and treble up. It does have carbon comp resistors, lots of them. Where would be a good place to start to reduce hiss? Resistors that go to ground? Others have said this amp is quiet when in good condition. Like my solid-state Fender, the reverb hums a lot.

Any feedback welcome. Here's the schematic.

Just curious. Does any one out there use a pre with their TU-8600, TU-8800, or TU-8900? I've been thinking about adding one to my system. Would really like to hear pros and cons. Thanks.

It is a very recent version (I think 1980), it has the toroidal transformer, 2 rectifier bridges and the modification on the protection board to eliminate the delay on the relay when switching off)

The flaw is that by setting the input sensitivity to -3 and 0 dB on any of the 2 channels you can hear a loud buzz in the speakers, the vu meters go beyond half scale and the final transistors heat up a lot.
By measuring the DC output it rises to 100/120 mV.
With the input sensitivity of - 12 or - 6 dB it works great and there is no abnormal heating.
The amplifier has all original toshiba transistors and the drivers are plastic, everything looks original, never been repaired.
The amplifier is set to 240V and feeding it to 220V (standard voltage in Italy) the power supply supplies approx. + 80 / -80V.
Connecting the input signal on one channel at a time everything works fine

I saw from the wiring diagram that the power supply should deliver +/- 105 V, do you think this could be the cause of the problem or do you have any idea what could be the cause of the failure?

Unfortunately I did not find the service manual on the net but only a wiring diagram, can you help me?
Many thanks to those who want to help me.
Massimo

Classic book, but long removed from AP.
Still avail on Archive ... but for how long?
Attached.

In perfect condition, measured and played for a few months.
EU, PayPal, 340Euro/pair

Used in Shamal project:
https://pkaudio.webnode.cz/shamal/

I'm Trying to rewire a multi input voltage Transformer to 115 volts US ,With a 5 wire primary side, without a schematic,. This transformer was made in Europe, Any information would be very helpful, Maybe a good quality replacement could be the fix.

And could you please help me locate service manual and schematic for ML 33 amp?
Thanks for any help.

I am considering trying a different cartridge. Maybe a MC. There is nothing wrong with the sound from this Shure MM.
Its just I don't know what more I might be missing.

If I moved to a MC I would also need a step up transformer.

The Shure has been highly regarded over the years, but would a change be a notable upgrade?

Budget, I suppose what it would take for a clear step up.

Linn LP12
I forget the model but I updated to their own light weight carbon arm a fews ago.
Ext. Psu

Yarqin Lesbox tube phono amp
Cary SPL50a preamp (upgraded)
Beard P50 tube amp (upgraded)
Rogers J149 speakers (just love the vocal ability of these) + 2 x b&w subs tuned to support.

How do you fine tune a speaker box, with batting or fill, before sealing it up? My initial thought was to leave the back loose and use strap clamps to keep it temporarily tight while doing listening testing.

This is a nice pair of Altec Lansing 288 C drivers. Everything works as it should. I prefer local pick up in Los Angeles area but will ship if required. I'm asking for US 1700 Dollars.

I wonder if this paper - which appears scientifically legitimate - could explain the advantages some claim with supertweeters?
https://journals.physiology.org/doi/full/10.1152/jn.2000.83.6.3548

Hey there,

if i would need to place my OB close to the wall (the subs are sealed so no problem with low hz) what would be the best way to do it?

Should i put them to the bare wall or should i put some diffusors/absorbers right behind it / next to it? If yes, which diffusor/absorber would be good?

Thanks

Hi,

First post on here, little to no electronics experience, but desperate times...fingers crossed...

After loving an old Musical Fidelity X-10D tube buffer, I have had a very knowledgeable friend put together one of the cheaply and widely available Musical Fidelity X-10D PCB clones for me.

The specific one being used is described as the PRT-09A and supposedly has an upgraded power supply along with a couple of other supposed 'upgrades' compared with the original board.

Board has all been built-up using mundorf evo caps etc and according to my friend, it all tests fine, but there is an audible hiss coming through the speakers when connected. Pretty loud too.

Guy from China who sold me the board has been helpful to be fair. AC input is set at 30 0 30, so he initially suggested lowering the test point voltage down (initially set at +36V, lowered to 28VDC), but no change.

GND is properly connected to chassis and the hiss is present with the board out of the chassis anyway, so not that either.

All resistors testing correctly.

Has anyone ever used one of these X-10D clone boards before and if so, do you have any ideas as to what the problem might be?

Appreciate the first thing someone will say is it's my own fault for getting a cheap PCB from China and you are probably right, but given the seller has come back, it seems to suggest he has faith in the board. Maybe.

Any suggestions greatly appreciated (chuck it in the bin?).

NB. All technical discussion will have to be relayed back to the guy doing it for me as my electronics knowledge is pretty embarrassing. He's not in for forums, so I said I'd post something.

Many thanks in advance.

P.S. been reading stuff on this site for years and whilst most of the discussion makes no sense to me at all, it is a fabulous resource, so keep up the good work folks!

A few years back I bought a set of drivers and the time has come to make something out of them. I have started to model the crossovers and wanted to hear if you think I might be on the right track.

Elements:

• ScanSpeak 18W/8531G00 (double)
• ScanSpeak 15M/4531K00
• ScanSpeak D3004/660000

Enclosure-wise, I am thinking that a 60 liter bass reflex box for the woofers and a closed enclosure for the midrange, something similar to Troels Gravesens Ekta Grande might be reasonable as a first trial box.

This is just an early sketch, so it is based on traced SPL and impedance curves from Scan Speak. Break-in and TS-measurements are under way. The crossover is modelled without a box and assuming all drivers are mounted with aligned acoustic centers.

I have attempted to integrate a baffle step around 500Hz and I have tried to keep the impedance above 3 Ohms.

What are your thoughts on this - on the right track here?

Another question, do you think it will be possible to drive mid+tweeter with a tube amp with this kind of impedance?

How was this done?

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Not sure this is the right forum, but giving it a try here. Looking for a schematic or service manual for a Behringer Model D synthesizer. Below is a photo of the ID info. Already have the users manual. Apparently most of it works, but the main output and headphone out are dead. Trying to help out a freind via long distance communication.

Thanks in advance.

well i just got back from switching an old VRP72 Neve from the original to an Atomic supply and the results are amazing now i just need to convince the studio owner to let me make measurements to corroborate the performance...

cooling fans are noisy so that warrants investigation.

Grabbed these 2 beautiful cabinets today and opened them to find something I couldn't surely identify. Pictures attached. All and any help is greatly appreciated.

Bonjour,
J'ai un clone JP200 et j'ai remarqué en sortie une oscillation amortie à très basse fréquence au moment de la mise sous tension. (0.1Hz)
Si on branche la sortie sur un ampli qui passe le continu ou sur un ampli qui descend bas en fréquence j'imagine qu'il ne vont pas aimer.
Avez vous remarqué le même phénomène que moi ?

Merci par avance pour votre aide
Cordialement

Gary Robert Rossington (December 4, 1951 – March 5, 2023). The last remaining original member of Lynyrd Skynyrd has died. He survived the 1977 plane crash that took other band members. that

as above. please send me a message. thank you.

Hey people,

a short, maybe silly, question. Would there be any advantage, or disadvantage, if the bleeder resistors which uncharge the psu capacitators would just be connected to the caps, when the psu is switched off. For example with a switching relay.

best regards J.

Hi All,
I've just had the primary winding in the transformer for this amp go u/s, no continuity, through white and green wires. Has anyone successfully transplanted a suitable replacement transformer and if you could you let me know what you used? Other then that has anyone has transformers rebuilt and if so any suggestions who might be able to do one like this one:
Many Thanks in advance,
Joe

Hi,

I was wondering how tracking is exactly being done in a 1-beam system?
I have been looking for more detailed information on the www but haven't found it yet.

Maybe a link to some more info?

Thanks... ;-)

What would be the latest Levinson or Solutiion amps and preamps I could obtain?
Thanks for any insight…

G'day Guys,

I need to replace a dual simmerstat on a Fisher and Paykel Stovetop.

That part is relatively simple.

The hard bit is that the faulty simmerstat has taken a wire with it.



As can be seen from the photos: The white wire is burnt out and will need to be replaced with the simmerstat.
However there are markings on any section of the white wire to speak of. No temp rating, gauge or voltage.

Voltage and temp rating aren't too hard - as high as possible something like 200 degree 600v would probably be ideal.
The wire gauge is what is stumping me.

Does anybody have any experience with such things that may offer a suggestion.

The simmerstat is a Robertshaw MPD-110 rated at 15A

Occasionally, crystal oscillators may be necessary for digital audio processing. China makes a lot of crystal oscillators, low and high frequency. They are good, however, their datasheets are far from normal.

Here is some information and tests on these :

https://drive.google.com/drive/folders/1Upn6FwOYexZBSDs3dr4gCHoRx7ajs_De

When I apply the remote the relay engages immediately. Would that be caused by a shorted capacitor or something?

Me and mamselle were listening to FM on a 440 mile drive. There was a revue of Robert Preston's "ouevre" and it occurred to us, what other male voices are so instantly distinguishable.

I will add Luciano Pavoratti, Roberto Alagna and Frank Paterson!

I don’t know about you guys but ordering parts is my least favorite thing about this hobby. Mouser and digikey are my go to places but their systems make it difficult. I can create a list on their websites but generating it accurately takes me way too long. I’m doing all this on my iPhone (11) using cellular data. I don’t have access to the Internet via wifi which may be the biggest issue. Please advise me how best to handle this
Thanks

Hey all, so the 4 relays on an Orion HCCA 8000.1D are not switching on after amp boots up, everything else is confirmed working/switching properly, and I see my 50Hz input signal just before relays, so while trying to figure out what is going on I realized I do not even tech I ally know what the relays are exactly for and/or what conditions must be met for the relays to a switch on. I have seen relay failure before but all 4 at once?

If anyone can help shine some light as to what the Speaker Output Relays are for, the conditions needing to be met for switch on, and other other pertinent info would be greatly appreciated. Ty 🖖🏼

I draw this xo circuit from a 15 yr-old Vocopro Karaoke speaker. There are no markings on the inductor or the mylar caps.
I don't understand why the 8 Ohm tweeters are connected in series. Should I replace them with 2 4-Ohm tweeters.
And what is the purpose of the resistors & mylar caps in series?
I'm replacing the 4.7uF cap and re-wiring it with 14 gauge stranded copper. Thanks in advance.

Hello
I have a marantz cd 84 cd player with a problematic DAC (Decoding) condition so it doesn't output audio. All button functions when playing, pause, FF , REW, Back and others on the display look normal. I have also checked all the JRC 4560 ICs for CD Out and Head Phone out, all are normal. The "mute" and "Kill" sections are also normal. Is there a father who is a digital audio expert who knows about this problem?
I once made a VCD Player using the Mpeg VCD kit by utilizing the Marantz CD-84 CD Player's EFM (RF) signal output and it worked.
Now I want to try to modify the normal EFM (RF) signal output that was converted to an external DAC but I don't know how.
Any digital audio experts know how to modify it
I look forward to a response from you guys here
Thank You.

I'm asking $50 each (two available) with local pickup in southern Michigan (Lansing area).

I have the original packaging, which consists only of the cardboard wrap from Peavey and shipping them is very dicey so I would prefer local pickup

I purchased these Peavey Low Rider 18 subs as new units, one at a time a couple of years apart, but have never used them. They seem to have slightly different construction: one has a straight sided basket and the other curved. I think Peavey updated the design but kept the same specs. Both drivers are in good shape as you would expect for the lack of any use and only storage in the original packaging. These would work well in an OB system.

Please PM me or post in this thread if you are interested in buying them.

Specs and price here:
https://www.parts-express.com/Peavey-18-Low-Rider-Subwoofer-Speaker-Driver-294-301

Hi guys (long time no see) I am building a less paul jnr and want to put a pizeo tuneomatic bridge on it my first question is after the pre amp can i go to a pick up selector switch to change betwen the pizeo and a humbucker

Hi good folks.

I would like to give my friend a preamp for his semi-acoustic so he can add some chorus etc. playing through his stereo. Speakers are low priced HiFi so must be protected from the peaks of strumming. Found a Boss AD-5 for cheaps and it has all he could dream of, but Im just worried of his speakers. I have PA drivers lying around, but no time to build pretty speakers for his livingroom 😊
Cheers!

The board is done minus the Nutube, will be using the isolation mounting system, but it looks fiddly and fragile, and my hands, eyes, and patience were diminishing, so enough for today. It will be powered by a positive Ultrbib and connected to a Maya R2R volume control and input selector. Have to get a chassis and mount and wire everything, that will be the hard part!

Hello,

Have tried to find a schematic for a stereo output stage for the pro version of 9038.
I read that the ones for the q2m version doesn’t work because of the higger output current. Correct?

Anyone have a working schematic with 4 output from Dac to 1?

BR// Daniel

I'm building an F5. In the build guide by 6L6, the resistor across the input, R2, is 47.5K. In NP's circuit on his Operation and Service Manual its R10 and 100K. I don't happen to have either resistor but I do have a 33K. Any problem with that? I don't want to order just a couple of resistors and spend $8 for shipping since I have all the other parts.

Here is a blast from the past. I designed this headphone amp years ago and just remembered how good it sounds and how easy it was to build. It’s a great project for anyone wanting to try etching their own PCBs. I used to do this all the time with laser printer toner transfers and HCl+H2O2 (muriatic acid and hydrogen peroxide).

This amp uses the OPA1688 opamp to drive 2x parallel OPA1688’s. This helps boost the output current. This was before the OPA1656 was available and I think changing to the latter will improve the output power. JPS64 did the home etch layout for me at the request of member Dibya - who I think also made this. Anyhow, kudos to JPS64 for a great layout and his generosity.

Here is the schematic:

Here is the home etch layout:

Built up:

Topside:

Assembled into chassis with an ultra low noise DCDC PSU (also home etched):

If you guys are interested in a real PCB, I’ll ask JPS64 to generate the Gerbers. But the point of this thread is to get folks to try the home etching method. I can explain more later but basically you make a laser print of the above layout on paper. Take that and iron it onto a blank copper faced PCB stock. The toner acts as acid resist. Then etch with acid peroxide solution and then drill holes if needed. This is why surface mount is nice - no drilling needed as the drill bits are very small and break easily with slightest side pressure. So a small Dremel drill press is a must.

It sounds great by the way. One of the easier home etched amps.

It was one of the nicest sounding amps in my collection at the time.

Hi, i was wondering if someone have some DSP knowledge? I have 2 speakers in the same enclosure for a portable speaker and was thinking maybe i can make it stereo. This can be done easely but if one channel put out bass and the other channel nothing , it will act as a passive radiator( the speaker with no signal ). So i was thinking could i filter out the bass and make it mono while playing the higher frequencies as stereo integrated in 1 channel.

Thanks!

This is the Discussion Thread for this paid advertising thread:
http://www.diyaudio.com/forums/showthread.php?postid=1234996#post1234996

It is for for product support, discussion, or feedback and can be posted to by all members. It cannot be edited by the advertising thread renter.

Class D in 1966. A filler article by Don Lancaster.

What is the best method to reverse engineer a woofer to a subwoofer enclosure. I am working on a subwoofer for my SIL. It is a 10" Bohlender Graebener Z sub. The voice coil rubs, and the cone has disconnected from the VC. My choices are; Try to find used replacement sub or driver. Have the driver repaired. Find a new compatible/equivalent replacement to fit the enclosure. I am thinking the 3rd option would be the easiest to source once I determine the requirements. The dimensions of the interior of the cabinet are;

14-3/4" Deep x 15-3/4" High x 11" Wide. It has a ~3-3/8" diameter x 9" long port.

Interior volume is taken up by a brace, the woofer, the amplifier & the port. The gross volume is ~1.4 cubic feet. After subtracting the brace, woofer amp & port the interior volume is ~.75 cubic feet.

Since I don't know the impedance of the woofer, I will go out on a limb and say it is 4 ohms. The amplifier looks A/B and pretty beefy based on the transformer.

BTW the woofer has what may be a part# (10P32) and date code (20030430D) if anyone can tell by this where to find a replacement. It has a stamped steel basket and a vented pole piece.

Im planning to build a speaker with Oberton 6B150, Faital 1440 and RCF HF950. Is this a stupid idea?

I cant find any information on the 6B150 here in diyaudio, is it a bad 6,5"?
I want to keep the speaker pretty small so thats why im consider the 6B150.

6B150:
https://en.toutlehautparleur.com/oberton-6b150-speaker-8-ohm-6-5-inch.html

HF950:
https://en.toutlehautparleur.com/horn-rcf-hf950-90x50o-throat-1-4-inch-front-11-81-x-11-81-inch.html

HF 1440:
https://en.toutlehautparleur.com/compression-driver-faitalpro-hf1440-8-ohm-1-4-inch.html

Sorry for my bad English..

//B

Hello,

While replacing one of the caps on my JL 500/1, I messed up and lifted the pad on the top of the board. The pad on the bottom is fine.
I hope the top pad was just there for structural integrity and using the bottom pad alone will be suffice.
Is this an issue and if so... how would I go about fixing it properly?

Any help is greatly appreciated.

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