I have for sale a Firstwatt F3 board, completed and in perfect working condition. Worked for some 30 hours in total. I will include a pair of the llu and the power IRFS as spares.

The price is 100EUR + shipping and paypal fee. The boards are located in the EU.

First I must note that I'm new... So please excuse some possibly obvious mistakes🙂

My problem is as follows: I'm in the UK and hoping to build a sub for my secondary system, I'm having trouble finding components at prices that don't end up as near as "might as well not risk it" to a sub I'm already running on my main system which I'm more than happy with.

Having bought a nice new system (speakers/amp/dac) for the bedroom, it needs a subwoofer. It's nothing high end, but in many ways betters my downstairs "main" system - So I don't want to do it a disservice by partnering it with junk. This is a music system. If it can handle music as I'd like it too, occasional movies will be no trouble. I'd love to build my own subwoofer if I can make it financially not-silly to do so... I enjoy building things, but parts seem rather expensive.

The crux of the matter is this: I've got a BK XXLS400 and some DSP in the front room doing a wonderful job, and I'm having trouble figuring out a driver/amp/box pairing that would out-do the equivalent B-grade BK. Now, I'd be happy with a XLS200 for this new system (£315). But when a XXLS400 is £410 and shakes my window frames when needed while being quick enough to blend in well enough for my ears, it's a tough sell. I've heard subs that do some incredible things, but this is a home system, my expectations are realistic.

As an exercise, finding a driver that models how my 400 performs on my main system, then looking at the price of plate amplifiers to power it, I'm left wondering how to get anywhere close.

My hopes are thus:
-I'd like bass down somewhere into the 20-somethings. Basically I'd like to be able to play The Mountain Will Fall by Dj Shadow without having to imagine the low notes.
-It doesn't have to be loud, but it has to be quick and deep (enough).
-I don't mind if I have to make the box a reasonably daft size/shape, but this isn't a dedicated hifi room.
-As mentioned, I can tame the room with DSP.
-I would quite like a plate amplifier on the back powering the thing. That's not a deal-breaker, but it'd sure be nice having all the right controls in what I consider the right place.

Is that possible for a novice builder, when I suspect the XLS200 at £315 (or worst case the 400 at £410) will do me well enough?

I can't seem to model anything that gets close - but then I am a beginner at this driver/box modelling stuff.

Thanks for reading,
J James.

I made a PCB for Bourns EM14 optical encoders.
This board is compatible with the MUSES 72323 volume control made by Meldano on this forum.

One board is fully populated and is working perfectly, I have one spare optical encoder.
Encoder type is: EM14R0D-M20-L064S
I moved from the ALPS to these Bourns Encoders as I had bad luck with the ALPS going bad pretty fast, the feeling when rotating the Bourns is from a much better level as well.
Reason for sale is that I moved from 64 to 32 PPR. 64PPR was about 1 full rotation to get from 0 to full output in my system.


As you will notice on the pictures, a 78L05 is installed to take care of the 5V for the encoder. I'm supplying this board with 12VDC, offcourse 15V is no problem either.
The 3V3 is not needed for this board to function.
The circuit is based on: https://www.diyaudio.com/community/threads/muses-72320-electronic-volume.220792/page-27#post-6419562

Populated board + spare encoder = €50 excl shipping. (this is lower than the price of the 2 encoder together!)



Any body interested? I will only sell both items together.

Had a bit of spare cash (rare these days) so looked into buying a better 12th gen processor.
I bought a 12400F but found it doesnt have graphics onboard.
So decided to go for 12000 series but with graphics and something a little faster.
The 12600k works at 4.9GHz and takes about 125 watts max.
I also looked at 12900k 5.2GHz but that takes up to 250 watts max !
So for 300MHz more it needs twice the power !
So went for the 12600k.
Seems to do the job well for what I need it for, mostly PCBCAD work and software development.
The 12900K is also about twice the price of a 12600k for not a big difference in performance.

Hello

I Had this non-working Sony TC-K850ES cassette deck in my shop for some time. A customer who was interested in this model messaged me to buy this. I restored the deck with original genuine Sony Pinch Rollers, Belts and an assortment of gears for the mode encoder mechanics. Replaced the SMD capacitors on the direct drive board and replaced the Standard capacitors on the motor controller board with Nichicon Fine Gold. After restoration the deck records and plays back as intended. The head was in good condition despite it being permalloy material. The deck has Nichicon muse in the recording and playback chains. A solid built machine

I noticed the deck was using some outdated op amps and a low grade 4066 chipset which downgraded the sound quality potential. I went ahead and replaced all op amps in the circuit with Texas Instruments NE5532P and the 4066 upgraded to the ANT4066B. A significant improvement now in recording and playback. Much better than the original state

I added the original advertising stickers specific to this deck as a finishing touch

The deck is now complete and with the new owner.

Hello,

I have for sale my modded Aleph J pcbs. These were just pulled out from the enclosures and replaced with an output stage similar to the F4.
The pcbs were come from Peter Daniel.

The pcbs have the aleph ccs resistors and the mosfet degeneration resistors replaced with a lower value, 0.33r, which gives higher bias current, 1.6a/fet.
The ccs that biases the front end is replaced with an tl431+bjt ccs.

I used the pcbs as monoblocks with 30x16x4cm heatsinks, having 2 mosfets on one heatsink(4 heatsinks in total).
The heatsinks were sitting ~30c above room temperature.
The power supply voltage was close to 22.5v.

All caps onboard are elna bypassed with ero.

The mosfets and the teflon isolators were cleaned.

I am attaching a few thd measurements.
My speakers are a bit inefficient at only 87db and also low impedance, 3.4r. This was the reason of needing higher bias.

Price SOLD

I have a pair of magi 3.7i and would like to convert the crossover from serial to parallel.
So I can bi-amp them and play around with better parts.

From the schematic it looks like, and I am guessing 😊

12 db on the tweeter
6 db band pass on the midrange
6 db on the woofer

Am I right?



Found the schematic here http://www.integracoustics.com/MUG/MUG/tweaks/neolith/
I don't know where I can find neolith so I hope it's okay to use his material

I have far too many projects either on the go or waiting to be picked up so I'm going to cull some.

A set of PCBs and matched LD1014D FETS, courtesy of Nelson Pass, for a clone of the First Watt F3 amplifier. Purched via a GB here on DIY Audio, details here;

https://www.diyaudio.com/community/threads/f3-clone-board-set-group-buy.373750/

I have:

2 x amplifier boards
2 x output boards
2 x PS boards
2 x LED boards
2 x XRK mpunting boards for LD1014D devices

The LD1014D devices were a gift from NP to the DIY audio community and I'm not looking to make money on them so the cost is just to recover my investment in the PCBs - looking for £25 plus shipping at cost.

Hi to everyone,

i wanted to share a project i was working on for a while. These speakers are a clone of the concept utilised by the german company "ME Geithain", which famously supplies the german state broadcast. The company is located in the former East Germany and the boss Joachim Kiesler was building speakers behind the iron curtain using technologies such as waveguides (RFT BR25/BR50) and line arrays (Geithain ITS50). The first quasi-coaxial speakers (Geithain RL900) also originated back in that time and were first supplied to East german Broadcast and opera houses. These were utilising classic bass-reflex enclosures with the addition of the cardiod version in the early 2000's.

The goal of this project was, to understand the influence of different damping materials as well as port size on the directivity of the woofer.
In the future, i want to compare the quasicoaxial arrangements to more traditional 3-way setups with a large dome and cd-horns.
But first, more about the current setup.

The tweeter is a Dayton ND25-TA which works fine for the job. Seas 27TFFNC/G would probably be better, but i was a cheapskate.
The midrange is a Faital 3fe22 without enclosure but damped with a basotect ring around the rear.
The woofer is a Transfer Audio AR 25. Again Seas L26ROY would be better but i got these for 30€ a piece and they have an xmax of 9,5mm one way.
The crossover is done using EqualizerAPO so there is only one D/A conversion.

Crossover is at 800hz and 3,5khz resulting in the characteristic dip in the directivity index between 3 and 5khz. This will also investigated further. ME Geithain has an in depth understanding of speaker directivity but decides purposfully to put this dip in the directivity index.
the enclosure meassures 33x36x25cm and the rear port equals 135cm² (1/2 Sd) At the moment the damping is archieved by stuffing the eclosure with rockwool but in the future i want to switch to dense polyester damping material. I will post meassurements of the enclosure with and without damping material next week. For the general size, there is a great excel file on Linkwitzlab which calculates the bass roll-off as well as the resonances which occur at the back of the speaker an need to be damped.

​

As title says I did buy this eBay DAC board and associated enclosure from along1986090. Used my transformers.
CS4398 with CS8416+CM102s, provides coaxial SPDIF and USB inputs.
First impressions:
Enclosure definitelly well done, with (almost) all necessary hardware, holes in exact locations to match the board. Kind of long (10", plus 1/4" front aluminium plate), I guess it can be used to add a dedicated headphones amp.
I did buy the pre-solderd board. Inspected with the magnifier glass showed an OK grade of soldering. PCB is in filled ground technique and parts are like shown in the picture.

Initial tests had a sligtly distorted signal and analized with my E-MU1820m showed a really bad signal. I did replace the 5532 that was on board with LM4562 that I hade around and everything started to look better. I suspect that the 5532 was either a fake or a damaged exemplar. There is no capacitor or resitors on OpAmp outputs, so it is easy to be damaged.
At -2dB looks decent. The output stage overloads my ADC input at higher than -2dB (all the other DAC's that I tested didn't manage to do that).
The output stage is not done per recomended schematics in the datasheet.

USB input:
CM102 locks only onto 16bit/48kHz signals. 16bit/44.1kHz is not supported in Windows7 mixer (WASAPI).
If looses the connection with the PC, static noise is outputted till the next power off/on cycle. The automatic switching could be done better I guess...
Altough in Win 7 there is no need for drivers, here is a package that provides a little more that basic USB. This driver looks like it does the resampling to 48kHz automatically.


Coax SPDIF:
Locks on 44.1-96kHz, 16 or 24 bit. I don't have a SPDIF source capable of 192kHz to fully test the CS8416.


Using Foobar with resampling to 48kHz would allow USB connection to work at any rate, but I do prefer the coax.

All in all, sounds decent, especially for the price. THD+N with LM4562 is at -94dB. OpAmp upgrade is strongly recomended and looks like some of the AC grid noise could be reduced by better filtering.
Direct coupling of the outputs leaves some higher levels of 10Hz noise creep into the output chain as seen in the coax graph (at USB I forgot to extend the range below 20Hz).

The seller give the schematics (at my request).

I came across 6 of these planar drivers. From the very small amount of info I have found, they look like they would make for a great OB speaker. Does anyone have any data on these? I have found very little. Thanks for any help...

https://headwizememorial.wordpress....e-ended-otl-amplifier-for-dynamic-headphones/ I'm interested in building this amplifier, but I'm unsure of the power supply circuit. The transformers are quite expensive and aren't readily available in europe. Is there an alternative power supply I could use? Is any 150vdc power supply suitable?

I brought this around 25 years ago (sn#12)when I had a second home in the country as the power was horrible and all over the place (105 to 127) and noisy
It died around a year ago and sadly ps does not fix it and offers a discount on other stuff
Around 10 years ago after hurricane ida the damage up here was really bad and I fought the power company and got my own pole and transformer ,it's been fantastic
So instead of salvaging for parts or dumpster contenders,I thought a simple 60 hz signal generation to an amp to get 120 v out
Am I dreaming or is it possible as it's just a ac generator
Thanks

Hello everyone, I was watching Erins Audio Corner a few days ago with Dr Geddes as a guest and he briefly mentioned group delay and used BMR drivers as an example, then said no more on the subject. I became very interested in the tectonic 2” BMR after reading Erins shining review. It seems like the ideal driver for my tastes as I can’t really hear sparkle (I’m 41 as of today) and the frequency and polar response are stand up, which is much more important to me.

But, I worry now about group delay distortion smearing in the time realm. I imagine that the sections resonating semi independently might take enough time in relation to the higher frequency cycles to matter where we’re very sensitive. Would anyone care to share their understanding of this?

Some might be tempted to point out that if I have to ask then I obviously don’t notice it even if it exists and it doesn’t matter then. The thing is years ago I didn’t know about the stereo illusion but now I do, and it matters. There was a time when I didn’t know that my car door speakers were beaming and there was a major problem in the upper midrange response at the listening position, and that most certainly mattered. I wonder if the tradeoff for the wide dispersion is group delay as Mother Nature gives with one hand while taking with the other. Is this concern valid?

I very recently began designing and assembling a small stereo system from the basic components. Kabd amplifier boards, open frame power supply, raw drivers, ect. I chose a two way system with the BMR 2” not because I couldn’t implement a decent three way, but because I felt I didn’t have to with the BMR. If there’s a real problem with the BMR’s I’ll be looking at the RS100 or RS75 and one of the reference tweeters. There’s a chance I’d go for one of the other Dayton 28mm tweeters because of availability. I have some beliefs regarding crossover points that might be too careful but this can wait to be discussed under after the group delay thing has been sorted.

My bookshelves currently have the Tectonic 2”, Anarchy 704, and RSS210 passive radiator on ~60w and 15w respectively. I’m really happy with the result but I want to make sure I’m not missing something that once I perceive it it’ll bug me ferociously. Btw is Erin @bikinpunk here? He’s Erinh on diyma where I’ve basically learned everything I know.

I'm temporarily going back to my Thorens TD160 turntable, in order to capture all my LPs in high resolution, cleaning the records from surface noise, clicks and pops at the same time. I have already done that with a friend's Luxman high resolution system, with V15 cartridge, and the results were fantastic.

The I proceeded, using Audacity, to clean the LP from all surface noise and eliminated all the clicks and pops I could find. Capturing at higher resolution, like 96KHz, would allow higher accuracy in the noise elimination. In any case, the files sound excellent. We still have to make a comparison between the original LP and the CD with the processed files and see how they sound.

Now I'm the process of building the RIAA preamp. This has been commented elsewhere, which generated a very constructive discussion, where I learned a lot, using LTSpice simulations to compare results from several highly regarded commercial designs.

The choice for the first preamp will be one using two FET ICs with a passive RIAA network between them. My idea is to use an existing RIAA kit sold by AliExpress, which will provide the pcb and some of the parts, then buying the ICs and some specific passive parts to substitute key ones in the RIAA filter.

My question is what to do with the very low frequency vibration, probably around 3Hz, that seems to occur apparently on all belt turntables. That's what I have been told it happens. My friend's turntable, where I made my first capture, also had them. Of course they didn't show on the captured digital tracks.

In my past turntable arrangement, I used a discrete two stage passive preamp, and the vibration was there alright. This preamp used a 470n polystyrene input series capacitor as high pass. To visually cure the vibration I had to lower the capacitance to 100n, which didn't seem to affect the audio quality.

Now I ask: should I worry about that? Can that low frequency intermodulate with higher octaves response?

The circuit I'm using now does not use an input series capacitor.

Does anybody have a 6P7S 6P7C tube spice Modell for pentode /tetrode

Hi guys,
I don't suppose someone could help me out with the wiring on the stepped attenuator I'm building?
I've attached a photo of the unit, and the resistor values i bought are for a series attenuator, whereas most of the guides online seem to be for the shunt type.
If I attach my meter between pin 1 and 3, the resistance adds up in series from zero resistance upwards as i decrease the volume from max, or if i connect 1 and 2, it increases as i increase from minimum volume. And this has lead to a couple of questions.

1. where should my ground, signal in and signal out be attached.
2. should RX or RY be the largest resistor? (i'm using the 50k figures from https://www.goldpt.com/r_series.html so the 10.2k value is what I'm looking for confirmation on)

Thanks, Tim.

Looks site wide?

Edit…..never mind, seems to be back to normal 🤔

Everything is sold !!

I bought a new streaming amp so I do not need a separate DAC anymore.

For sale a Soekris dam-1121 DAC from 2019 with the latest firmware update installed.
This is the version with 0,02% resistors.
No soldering done, the connectors were used with female (push-on) adapters so the PCB is really like new.

Asking 100 EUR.

From when I was building it with LT3045/3094 voltage regulators:




Some other bits and bytes:

About 12 years ago I modified my CD-player with Burson discrete OpAmps (dual version) and a Tentlabs clock with 16.934 Mhz XO.
These do have soldering marks but are in 100% working order.
I switched to streaming a few years later so these have only been used approx. 3-4 years ?

Asking:
Burson dual OpAmps: 50 EUR
Tentlabs clock incl. XO: 50 EUR

I have an idea to build a case for a piano controller to convert it into a stand-alone piano.
Multiway speaker drivers would fit very naturally into a piano-ish shape.
So it would look a little like this cosmetic case, except contain speakers and amps.
(Doesn't it just cry out for a woofer to fit in the curve, tweeter just where the treble notes should be?)


It could be built as a sealed box speaker, but a real piano is more like an open backed dipole I suspect.
That would partially null out the bass frequencies in the approximate plane of the cabinet.
Does this actually happen?
I've never jumped up and down at a piano recital to compare the sound. 😉
I am sure the polar response of a real concert piano has been studied, anyone have ideas or references?

David

Am I supposed to be telling horn response this ‘advanced centerline stuff’ or why am I not just describing the physical endpoints of each of these perfect rectangles that are all the same? After all, that’s what’s gonna determine these interstitial resonances that fill up the frequency response, right? I don’t have the atypical scar at 3 x 1/4 fb that exists in a compound pipe, or something that has misaligned the three to one relationship or created an exit where the mouths are disconnected from either side???

If you play with the sim, and you change the cross-sectional area of the short side or the length of the short side, you’ll see that scar immediately show up…. You can do the same thing by adding a flare rate or something to the long side, etc. etc. but all of these things screwup what was otherwise was a perfectly smooth and established band with with no phase anomalies or hiccups.?

Hello.

I'm currently trying to make a DIY DSP for my PA system.

I currently have an Arduino Nano and plan to use that, however, I do know that the Arduino has limitations because it doesn't have an audio chip (I think).

I was wondering if anyone knew any way I could do this. The main thing I'm looking for is a crossover (for my full range speakers and subwoofer), however ideally also some other things like an EQ of some sort (maybe 3 band up to 30 band, or even perimetric), but that's not as important.

I've found some forms and other things that show people using a chip of some sort which handles the audio processing, and the Arduino is controlling it all.

Thanks in advance!

My issue is different than that discussed on the oscillating tubes (as i understand it). I appreciate your input.

Equipment: 2 Manley Snapper power amps; just serviced
Connected: dedicated circuit for amps

Even with nothing else connected to the power circuit in the room, interconnects removed and every other breaker in the house tripped, I have a rhythmic hum on the speakers (low frequency) which coincides with changes in brightness of the EL34 tubes (blue fluorescence changes). Also bias changes in rhythm with the noise.

There are no ground loop issues (no noise except for this noise and the noise remains with nothing else connected, no interconnects). Also, problem happens on each amp even when only one of them is powered up and connected.

I also swapped tubes, outlets, connected to a remote circuit on the house (100 foot extension cord). I changed the breaker to a CAFCI breaker and checked all ground connections and ground rod.

I'm left to think I have an issue with incoming power (which FYI ranges from 125.1 to 125.4 volts).

I have tried HumX and also iFi Ground defenders with no improvement. I have ordered a Decware Zen Line Conditioner (long lead time) and a couple of VanAlstine Humdingers.

FYI, the amps don't have a mechanical noise (that I can tell).


HELP!

Recently, I bought a PCB from A* site. Unfortunately the seller didn't send me the exact circuit diagram, and I had to draw it myself. I'm a beginner at vacuum tubes, so this connection is very unfamiliar. I'd appreciate it if someone could verify this. Is this diagram safe and accurate?

Paul

... but still really cool. If you need to, you can set closed captions in English

Login to view embedded media

I am interested in buying Scanspeak R3004/602010 if anyone has a pair in good condition. Thx

Hi, I have an existing PS using multiple chokes in the DC filtering for B+ supplies, that is fed from a valve rectified supply. The rating on one inductor in the circuit circuit is 60 mA and the circuit is at about 30mA steady state and the other is 150mA rated and has about 110mA steady state. So all good, and in the circuit they have been having no problems for about 20 yrs.....

So Why the question? Well I am changing some elements of the PS and some values of capacitors and the layout and on my new designs I see some large peak currents on start up modelled in PSUD2 with these new designs (and also actually the old designs)

So my question is should I just ignore these peak values as fake news (or irrelevant transient peaks that should not trouble the inductor) or should I pay closer attention to them?

The rectifiers are 5u4GB for the PS in question.

Is it ok to use speakon connectors for speaker level wiring?

I am building boxes and will have cross overs in a separate compartment. But want an easy disconnect through wall connector .

Will these be fine if used in a speaker 100-150watts?

https://www.parts-express.com/Neutrik-NL2FX-SpeakON-Connector-2-Pole-Cable-Mount-092-198?quantity=1

I am going to rebuild the crossovers on my Horned Heils from the Horned Shoppe. The originals appear to be Solen and I would like to upgrade them to one of the below options:

• Jantzen Superior or Alumen
• Audyn Cap Plus or Copper
• Jupiter
• Dueland

I am open to any other options as well. I would just like to get more detail out of the new crossovers. I am using the original inductor but upgrading the cap and connectors.

Thanks.

Purifi's PTT6.5W04-01A woofer group buy

You are invited to join a North American group buy of the Purifi’s groundbreaking long-stroke ultra-low-distortion PTT6.5W04-01A woofer, and optionally the matching PTT6.5PR-01A Passive Radiator. Owing to Purifi’s policy requiring orders go to a single address this gets complex, thus the long post.

Announcing the Purifi group buy will close January 31, 2020. At that point we will aggregate our funds and place the order with Purifi. Logistics require we place a single order so we will not be able to accommodate stragglers after the cutoff on the 31st. Sorry about that, I am a procrastinator myself but in this case we are early adopters and a decision is required.



Many of us have taken note of Purifi (Purifi Audio), a new research focused company in Denmark founded and staffed by a distinguished group of Hi-Fi industry heavyweights. The team at Purifi (for the roster see About - PURIFI) has extensive experience in the electronics, loudspeaker, and business sides of Hi-Fi. A following post to this thread will include links to both Purifi’s technology white papers and independent testing and listening reviews.

On the loudspeaker side Purifi’s initial offering is the PTT6.5W04-01A 6.5 inch woofer, a design that reduces distortion by tens of dBs while remaining linear to extreme excursion levels. This promises to allow bass depth with low midrange distortion that is normally the providence of large speakers using 12 and 15 inch woofers in jumbo multi-cubic foot boxes to be had from a ½ cubic foot / 15 liter enclosure 2-way system.

Purifi’s PTT6.5W04-01A is manufactured in Denmark. That is a good news bad news situation. Good news is for decades Denmark and Scandinavia have been a primary source of state of the art loudspeaker drivers and with European manufacturing by this team quality is a given. The downside is price, it does cost to manufacture in Europe, in this case $250 to $350 per driver depending on where one falls on the price breaks. So let us band together and save some dollars.

Purifi conducts all of their business in Danish krone, 1 Danish Krone equaling approximately 0.15 United States Dollar. As of this posting date cost in Danish krone and US dollars are as follows. These prices do not include shipping.

PTT6.5W04-01A Woofer Quantity based pricing table

Min__Max__Unit Price DKK__Unit Price USD
1____3_____2,329.00______$349.35
4____5_____2,108.00______$316.20
6____7_____1,871.00______$280.65
8____8+____1,663.00______$249.45

PTT6.5PR-01A Passive Radiator Quantity based pricing table

Min__Max__Unit Price DKK__Unit Price USD
1____3_____844.00________$126.60
4____5_____761.00________$114.15
6____7_____672.00________$100.80
8____8+____593.00________$88.95

Obviously if four or more of us commit to a pair of woofers each we can access the 8 pieces and above price break saving $150 to $200US on a pair. The exact savings depending on shipping costs, which I intend to pass on at cost. There will be no markup on this effort, I am donating my time to encourage fellow early adopters. That time will primarily be breaking the big shipment from Denmark into individual pairs, re-packing, and shipping onto the group members. Alas, to access the 8 and above price the shipment must be to a single address so a second shipment within N. America is required. I do have a commercial shipping address, which gets us a discount from Purifi’s shipping service DHL and avoids porch pirate worries.

Thanks to Purifi’s web store we can see exact cost to land a group buy to USA. The following tables show those costs as of January 2020 with shipping to Oklahoma. The first table for a group order for four of us to get one pair of PTT6.5W04-01A woofers each, eight drivers total. The second table shows the cost to buy a single pair of drivers as a comparison.

PTT6.5W04-01A Web Costing Group Buy

Item_____Quantity___Unit Price DKK__Unit Price USD___Order Price DKK__Order Price USD
PTT6.5-04___8_______1,663.00_______$249.45_________13,304.00______$1,995.60
Shipping____1_______1,312.00_______$196.80__________1,312.00_______$196.80
__________________________________totals__________14,616.00______$2,192.40

Unit cost group buy landed in USA $274.05
Pair cost group buy landed in USA $548.10

PTT6.5W04-01A Web Costing Individual Buy

Item_____Quantity___Unit Price DKK__Unit Price USD___Order Price DKK__Order Price USD
PTT6.5-04__2________2,329.00_______$349.35_________4,658.00________$698.70
Shipping___1__________622.00________$93.30__________622.00_________$93.30
_____________________________________totals_______5,280.00_________$792.00

Unit cost individual’s buy landed in USA $396.00
Pair cost individual’s buy landed in USA $792.00

Bottom line is buying individually a pair cost $792 vs. as a group $548 + Oklahoma to you shipping.

If you want to join this group buy reply to this thread and send me a personal message with contact info. I plan the process to proceed as follows:

1. Recruit enough participants to qualify for quantity 8+ pricing.
2. Close participation in initial group buy.
3. Check costs to buy woofers (and passive radiators if anyone orders those) and shipping costs Denmark to Oklahoma, communicate each individual’s total to participants.
4. Participants pay using PayPal to group buy organizer. Your PayPal receipt will state “Expected delivery time 6 – 8 weeks”, I will try to beat that, most of that will be determined by Purifi’s build time and shipping including clearing USA customs.
5. When all funds arrive order is placed with Purifi. Be aware Purifi states “Note that this product is made-to-order. Expect approximately 4 weeks delivery time.”
6. While Purifi builds and ship woofers group organizer will prepare boxes and packing for shipping leg within North America.
7. When shipment arrives in Oklahoma group organizer will break down into shipments to individual participants, determine cost, and communicate to each participant their North American final leg shipping cost.
8. After participant pays their individual within N. America cost group organizer ships their order.
9. Woofers arrive individual participants’ workshops where they are installed in boxes. Jaws drop, sonic bliss ensues.

Obviously at this level of cost to entry we have a classic case of it is expensive to participate at the cutting edge of technology. I expect the cost to entry will surface individuals with the commitment and means to participate. Given that one should not need to say, yet out of an abundance of caution I will; do not be a wimp! Once you commit do not try and back out! This is not Amazon with free returns, you buy via this group buy and they are yours. If ultimately the sound is not to your liking it is on you to store, scrap, or sell them on. I do not intend to allow that reality to give Purifi a pass on their quality obligation to deliver product as specified to us. What I will not allow is audiophile wimp buyer’s remorse with excuses like “I don’t like how it looks”, “I’ve decided to go a different route and want a refund to help fund that project”, or “upon audition they lack a certain air and “je ne sais quoi” my incredibly refined hearing cannot do without”.

I am excited the Purifi PTT6.5W04-01A is a true breakthrough, something rare in such a mature century old technology. I hope you will join me as one of the first to explore it.

Has anyone on here experimented with felt in reducing or eliminating baffle diffraction? I have a situation where I have to have a large baffle and was thinking of just using a ton of felt covered in grill cloth or something to eliminate the diffraction. Would having the baffle back about an inch from the speaker front and fill that gap with felt, would that help? This is what I am currently thinking as otherwise it would be a wide baffle of about 16" x 29" wide open baffle.

The speaker is going to go into a cabinet so I would think a large baffle would be better than a slim speaker in a cabinet, yes? Maybe this should be in Construction Tips? If so feel free to move!

I tell you that what could have been a simple repair I have complicated by an oversight, I was repairing a hifonics bxi2610d amplifier which had damaged the source mosfets and some of the audio stage, so as not to make it too long I reached the point of I had an oscillation signal in the 4 banks of the audio stage mosfets, but in one of the banks the only irf9640 got warm , when checking the signal with the scope was a bit strange. The signal was not completly square it has a peak of correct voltage but almost inmediatly, it fall at about 2 volts peak to peak, looked like a continuación of square wave and sawrooth signal.

Hi all

I was hoping to get some opinions on using car speakers in a home HiFi setup. The reasons I want to do this is purely the range available, cost and ease of acquiring car speakers - I want to go as slim as possible.

The speakers I'd like to use are either the Infinity Kappa series or the Blaupunkt ultra-flat OD series. Whichever I decide to go with, each cabinet will have its own amp and crossover.

Also, I read on the DIY High End website (http://www.diy-high-end.com/amplifier/) that mounting low frequency speakers back-to-back improves sound quality, has anyone tried this?

Many thanks.

Mo.

Who else has built these? I'm thinking I might be the very only ones on the planet...🙂 Let me hear from other builds and what you think....

Coincidentally, I have just started testing a new amplifier.

This is balanced like all my stuff.

It uses a 13D3 input diff pair. This is unusual in that I am flying in the face of theory, because whilst it has a conventional cascode SS current sink at the bottom, it has active loads on the anodes. Most people say that this will not work as the sources and sink will fight each other.

Well it certainly works at DC; it is passing more or less the design current.

The next stage, is a pair of D3As, as pentode cathode followers, which will be DC coupled to the output valves, a quartet of 6CK4s.

I am having a bit of trouble testing because obvioully I have a -ve supply and am having difficulty with getting the voltages right in testing without the output stage. Really I need two adjustable power supplies; and I have only one variac!

More later.

7N7

Hello all: Having an issue with one of the mono block that I built from P. Millets schematic and was wondering if anyone can shed some light on the issue. So I built the P.Millet 50w mono block engineers amp using his board and followed the schematic exactly as prescribed and the amp worked great. I had it in storage for 4-5 months and recently hooked it up, checked the bias (running it between (350-425mV) and everything seemed in spec. Then I started hearing intermintent static on one channel and notice bias voltage jumping past the 500mV and beyond. I check all the tubes and they were good. So my question is what could be causing the spike in bias voltage with the static to the speakers? I looked at schmatic and was thinking it could be the IXCP10M45 current regulator? This seems to occur around after 30 minutes of playing, I have also traded out all tubes and problem still persists. Thanks for any assistance in this matter

Interesting- Quad ESL63 vs SimPole OB March 2011
https://www.zelfbouwaudio.nl/forum/viewtopic.php?f=3&t=13334

Visaton FRS8
https://solen.ca/en/products/frs808

Speaka 150/170 (na)
https://www.rapidonline.com/speaka-150-170-loudspeaker-10in--55-3605

(* moderator * can you add to title " OB diy " tia)

So I want to swap bass drivers in the U15 to JBL 2240. These are awsome speakers but what would happen if I swapped the bass drivers for 2240s? Same spl. Obviously I would build cabs but now response is way lower. Win win?

Hello,

i never build a enclosure yet, but have been studying and simulating in winisd some possible projects with two types of speakers i have

i always design the box the way i could get the more bass possible, thinking that will be the best final response of the enclosure im my room

but i saw the Scott Lindgreen video in NWAS 2018 saying that he consider the room gain when designing a speaker letting the bass part of the spectrum a little shorter then desired because when in the room the bass will be reinforced and the box will deliver the desired full response

i find this video where he show how to estimate the room gain while desigining the speaker, so we can see if it will match our desired final response when playing in the real life of our rooms

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my question is:

this method is ok to do?

because i am a fraid i will design a speaker with the most bass possibel in the winisd and when palying in my room it will sound boomy or not good because the room gain that i dont consider in the project

thank you

Hi
I be been using a DAC/preamp to successfully drive my Class-D power amp, which has a 10k input impedance.The DAC/pre has an output impedance around 200 ohms.
I also have a pair Dayton DSP-LF units that i'd like to insert to analyse and room correct the lov end of my speakers; which should improve bass sound, since my tower speakers are placed out into the room for best stereo image.

However, I discovered the DSP-LF specs say its output is 1v and 10k ohms output impedance.
.
Using a 6ft shielded interconnect between the DSP and my power amp, if source and load are the same impedance, how would that affect the audio signal, and would there be a negative impact on the sound?
Alternatively, I could run the 6ft cable to the DSP, which could sit right at the amp...
Thanks

In the Foam Core thread, I posted the Decware DNA BLH to see if there was any interest in doing a DIY version of it in easy foam core. See post here: Foam Core Board Speaker Enclosures? - Page 175 - diyAudio

Here is Bcmbob's build in XPS foam:


There is some interest in proceeding with it as I can see that as of now, there have been 32 views of the approximate dimensions that I posted as a pdf plan here: diyAudio

The DNA was designed for use with the now discontinued TB W5-1880 driver. In the interest of trying this design out in FC on a budget, I spec'd the following cheap 5 in aluminum cone driver from MCM: MCM Audio Select 5'' Aluminum Cone Woofer | 55-1870 (551870) | MCM Audio Select

I simulated the DNA in AkAbak with the following horn expansion profile that I derived using dial calipers from the drawing (13 segments total with the first one being the throat leading to the main horn passage. The throat width is equivalent for a 2.5 in dia hole.)


The main driver chamber was estimated to have a volume of 16.1 liters, and the throat hole leading from the chamber to the start of the horn passage is assumed to be 2.5 in dia.

The result of the simulation for the DNA with the W5-1880 driver appears to go down to about 30 Hz in bass extension - not bad. This is for the speaker placed with baffle 18 in from rear wall and 4 watts of power with listening position at 3 meters away from front baffle.

For the cheap $13 MCM drivers, I had to reduce the driver chamber volume by 6 liters to 10.1 L and this provided a much better response due to the much stiffer suspension (smaller Vas). With this driver, the bass shelf is a little tilted but nonetheless smooth and goes down to 40 Hz. The last plot shows the driver cone displacement for the MCM 55-1870 driver at 4 watts. With appropriate stuffing in the main driver chamber the resonances and peaks should be reduced significantly - so ignore the sharp peaks when viewing the plots. I still have not figured out how to implement damping/stuffing in AkAbak.

The design appears to a good one and I think worth pursuing even with the budget driver - 40 Hz extension and it appears that there may be enough bass gain to avoid using a BSC.

Some recent plans from DimeStore Dynaco:

Hi there!

What is the expected THD at 1W for a 6L6GC SSE (425V plate voltage 62mA cathode current)?

I am measuring between 2% and 3%

Hi everyone
i am new to this forum, and i would need help if any expert can do it.
I would need the crossover diagram, with the component values indicated, for a pair of proac response 1 (the first series of 1990/91, the one that had external crossovers.)
I can't find any information on the web about these particular crossovers, and i need to replicate the original circuit and values.
if there is anyone who can help me i would be very grateful.
Thank you
Luca

I got an idea about a speaker & amplifier combination. I thought it would be wise to ask if others have experiment with this.

So my idea is to build a system with these features:

• Mark Audio Alpair 12P full range speaker drivers (two)
• Approximately 3 cubic feet or 85 litres sealed cabinets (two)
• Quite tightly muffled box cavity with plenty of teared cotton ribbons
• A current-drive made with a transconductance amplifier or by other means
• No other drivers or any passive filters
• Decent cables, nothing fancy

I already have the two sealed boxes made of thick chipboard. Purchasing the drivers and building amplifiers would be the next big steps.

I got few questions also:

• Would the mechanical damping flatten the resonance enough or should I also prepare to build a filter to take care of that low frequency resonance?
• I thought about covering the speaker boxes with acoustic cloth (speaker grille cloth). The boxes are right-angled. I would cover each box with snugly fit cloth hoods. Anyone done this and does it work well?

Can somebody explain this to me please? Next to my main set up is a glass-fronted cabinet. The sub next to it causes no problems. 20 feet away in the opposite corner of the room, on a separate system, my desktop speakers rattle that same cabinet. Why does this happen? The desktop speakers are small units with 6.5" woofers - they do not produce earth shattering bass.

Picked up Dayton Audio Version-

Using their provided "project" and I get a lot of static even with external amplifier off.
I've tried my AVR and 3 separate power amps as power and still static. Ive tried different USB power- and leaving the programmer plugged in and not plugged in. This is by far the cheapest solution for redoing my theater as active- so trying my best to get this to work, But that static is just horrid

Trying to make 3 way crossover- for HT

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For sale 1 PhiDecaDAC with 7th order filter. Asking $50. Buyer pays shipping cost. I'm located near Seattle WA.

I'm only selling because I built my own DAC using TI PCM1794. I'm proud of my work, so I've replaced the PhiDecaDAC with my own in my system.

Here is the page with all the info about the PhiDecaDAC:
https://www.diyaudio.com/community/threads/phidac-hex-kits-with-pre-built-filters.354799/

PhiDeca DAC needs a 15V regulated power supply, max current draw is 160mA. A 500mA rated linear wall-wart is suggested.

Hi,

Is this amplifier worth a try or is it just junk?
Can i use it as a replacement amp in a subwoofer Plateamp if voltage/current is ok?
Any ideas or should i go for something else?
Maybe some diy Class-D amp will do better?

https://www.aliexpress.com/item/100...216694111479612912e1aef!12000028507966479!rec

Cost: 2€ each pcb

Shipping in a padded envelope (not tracked or insured):

• germany (without islands) : 2,50€
• world wide (without UK, sorry guys to much paperwork for the customs): 4,50€

New batch arrived!

I'm working on an amp that uses an 8098 transistor,,, the schem I found for it shows a common 2n3904, so I ordered them... When the new parts came in, I started to replace them one at a time, but this one was 8098... Seems 2n3904 was used on earlier builds, but 8098 is rated C-B v 60v vs 40 for 3904,,,
and C-current max is .5v vs .2v,,,

Can anyone help with a sub or 8098 source? This is how the transistor is labeled...
AMPS
8098
ECB

TIA

Hi everybody,

I have installed Daphile (version 20.12-x86_64) on my mini PC (MINISFORUM UM350 Mini PC AMD Ryzen 5 3550H DDR4 16 GB RAM 256 GB PCle SSD Mini Computer, Dual-Band WLAN HDMI/DisplayPort/USB-C 4K@60Hz, 2.5G RJ45-LAN, 4X USB 3.0 ports). The programme worked, although it often lost connection to the router (via wi-fi). For this reason I tried to click on the button "reset to the latest firmware settings", but since then the programme no longer loaded, no longer let me enter via the GUI, and I was no longer able to reinstall it. I have tried all the latest versions, but it only goes as far as the 'Waiting for network connection' screen and does not go any further. There's just no way.

Can you help me? Can I try something else? Bear in mind that the mini pc is fully functional (both linux and windows see the network and wi-fi cards and can be installed on the pc itself).

Looking forward to your suggestions.

Thanks


Alessandro

Bill Gates WINs again!

My detest of windows has been overwhelmed by my need for it, too many things are slowing my roll by trying to stay free from its grasp.

My main concerns are being able to use hornresp, my new dats v3, and some sort of box calculator……...question is what laptop to get during the Black Friday deals? I’ve narrowed down performance/price point to this (see pic)………
Will i5/8gb/512gb be enough or will i regret not going for broke on a i7/16/1tb ? It will be for audio related use only and not cluttered with anything else.

Does this one look decent? I like the fact it converts to a pad…….reviews praise speed/ease of use, biggest complaints are heat/battery life (4-5hrs)
battery life isn’t really a big issue for me but heat may affect longevity?

thx, Bob

Hey guys, I want to build a Raspberry Pi media player, inside Mac classic case, for my workshop. Since I'm new to everything related to audio equipment any help and recommendation is appreciated.

I own this nice Lenco 75 that as be refurbished (quite a good job has been done) but I stil got a noise sounded in the mediums.
This rumble is displeasing and i tried to fix it but it’s still going on .
Arm is Pro-ject carbon with Pickering XUC cartridge . The turntable is placed on pro-jet damp-it to avoid vibrations .

It may be the bearings .

Can anyone give me advice to solve it ?

Since I'm building my own home from scratch I have a few options doing cooler things than average, whilst still keeping the wife somewhat happy.
My latest plan is to;

1/ Get a Danley DTS10

2/ Put it in my office (which borders on my livingroom home cinema)

Which will then look something like this: (of course the black part will be hidden behind the white panel)


Is this actually a good idea? =) Thoughts welcome. Or should I try infinite baffle? (i am worried it would make the office unlivable during a good movie on the other side?)

Hello everyone,

I currently store my records on the wall behind the speakers, about 3.5 to 4 feet. Is it ok, or should they be moved somewhere else and my equipment rack placed between the speakers? When I look at pictures of other high end rooms I see a little bit of everything, but more often than not, there is generally either the eq rack or nothing at all. I would experiment myself if it was easier, but that's a lot of work if there was hardly any benefit. My imaging depth does extend right up to the record storage but with a bump out on the wall behind the right channel, I wasn't sure if the records were actually helping making the back wall 'flatter' as far as the speakers were concerned or hurting.

If I put the equipment behind the speakers, my speaker collection will be placed to the left along the wall where the rack currently is.

What do you think - keep it or move it?

Anyone know of a good replacement for the outputs in this amp ?

Originals are SSP45N20B

Hi,

my NAD C326BEE goes to protection mode. But when i put jack into headphones socket, amplifier works ok. I tried to disconnect headphone board (J101 from scheme), result is the same, amplifier runs ok. I changed 6.3mm socket but with no results. Has anyone experienced such problem? Attached headphone board scheme.

Used twice for a project with a JL audio 10w6v2 (for sale also) . Didn't have time to complete the project, so I let it go.

Smoke free environnement

Feel free to contact me if you have any questions.

500$ CAD / 375$ USD+shipping

Hello everyone!

After recently completing a pair of 2-way Synergy-style horns, I've come to the realisation that a point source design forever needs to remain in my future 🙂

While I'm in-between projects, I started reading around, and ended up on the subject of Coaxial drivers. Considering that there are studio monitors out there (e.g. Tannoy designs from the 1970s), I can't help but think it's a technology I should explore.

The main reasons for this are:

• A point-source is possible because of the physical arrangement of the LF and HF drivers
• Building an enclosure for a driver does not appear to be that complicated
• Building a crossover hopefully won't be too difficult as well, just mainly compensating for the increased sensitivity provided by the compression driver

Is it currently feasible to use a coaxial driver to cover, say, 150Hz to 20kHz?

Listening distance from the speakers would probably be around 10-12 feet.

What drivers do people recommend nowadays? My current readings on this forum seem to point towards BMS and B&C as good options, but I'd like to hear from the experts as to what your thoughts are!

Thanks!

Bought years ago but only used twice. I never had the time to complete the project. Reason to sell : kids.

I have the original box, smoke free environnement

I'm in Canada

350$ CAD (260$ USD)+shipping fees, paypal

Received a Technics SA-500. No sound and signal meter was pegged no matter what as well as power meter indicating, until I found a faulty solder joint, that solved the signal meter peg in FM mode and the power light issue, although AM still pegs.

Symptoms left

no stereo indicator no matter how strong signal
power transistor for left channel will not adjust.

former owned also indicated he had crossed the speaker wires. Fuses in protection circuit were 32v 20amp!!!! I am assuming he replaced the correct ones with these. They are now 125v 5a, also checked protection relay and it appears to be good.

wondering if power transistor blew on one or both channels. Also the variable resistors for left channel does nothing.

anyone ever run into this…lol

thx

cleaned all pots

Quite a lot of DIY amplifiers have their heat-sink(s) mounted externally, such as on the sides of the chassis (in many cases, they 'are' the sides); this all seems very sensible. Conversely, quite a lot (probably most) domestic/hi-fi amps that one can buy have the heat-sinks inside the chassis, with vents below and above; this is visually quite neat (and possibly has some minor safety advantages if the heatsink got very hot). Neither is 'wrong', they are just different choices.

To that end, I'm wondering is how much of a performance reduction is there likely to be if using a heat-sink internally? Assuming a very open wire grill were used below and above, is it likely to impede convection enough to make much difference?

Thanks,
Kev

Wondering about the available events on QCC 3034 and corresponding default sounds. In attached file, can anyone

1. give more explanation to these? What they are?
2. How can you listen to the qcc default sounds for these events?

What is a TCR504? As used in an Arcam Delta 290

I have used the ol mighty search engine but I cannot find a Datasheet. I assume it is some kind of CCS?

Can I connect a 600w car subwoofer directly to a 800w home amplifier without any other thing?

If cannot what should I use?

I also want to know what is the difference between car subwoofer and home subwoofer.

randomly noticed this driver in 16ohm variant has higher qtx that would seem to suggest it as a good candidate for a sealed box . would the higher impedance cause any problems other than drawing less power which doesn't really seem a problem ? lower sensitivity perhaps?

Hi Everyone,

I recently picked up a non working Pioneer SX-770 receiver. After a full rebuild of the amp board + general recapping the amp works well and sounds fine.
Concerning the FM tuner, it was catching zero signal , so after a clean/lubrication of the tuner gang contacts & some basic alignment, it now picks up all stations really well, with a strong signal & with stereo/muring working fine.

The issue is the frequency on the dial doesn't correspond to the station, so it reads about 1.5MHz too low on the dial. I adjusted the LO screw as much as I could but this only has relatively minor impact.

Normally I would just adjust the TCO (Tuning cap oscillator) a bit to better align the dial, but in my case it justs turns endlessely with no impact whatsoever on the sound or station. I figure the cap is broken.

The FM front end has a kind of soldered shielding that I cant take apart. Also I don't want to fiddle with the pointer on the string.
Is there anyway of adding an external adjuster perfroming an equivalent function as the TCO cap ? Not sure how it works not what it is (adjustable capacitor ?)
Or maybe I will need to take the shielding off, but will need a powerful soldering iron for that, and try to fit a new TCO cap if these things are avialable.

Would appreciate any advice.

Hello Chaps,

I plan on building a classic style stack of speakers and wanted to have a dedicated top section which house two BMS 4594, I want to take full advantage of a narrow vertical coverage with increased SPL of stacking the two drivers to line array style waveguides as depicted here. http://copyright.lenardaudio.com/laidesign/images/a07/a07_evlens.jpg

so with two stacked vertically I was trying to find out how I can take advantage of the midrange freq of the driver with a horn flare exit after the waveguide.
Are there any horn design principles at hand that go in tandem with the path correction from the waveguide itself, I was hoping to get a good load from 4-500hz.

My guess is that with creating a larger format horn that I would need to be careful of how the horn exit affects the HF creating a narrower beam along the horizontal axis and balancing that with trying to load the line source lower. Do I also need to take into account the path length of the waveguide itself as I am presuming that has some inherent loading with the small line lengths that create the matrices of path correction OR do I treat the line exit to be a completely new source and design the horn how I like. That then poses the question does any horn curve function have any advantage at this point, tractrix etc.. or just go straight conical with a flare. As for the vertical I would just place a smaller flare within the range of the vertical dispersion. Attached is a very rough exacerbated version of what I mean.

Sorry for the "wordiness" its been difficult to find much information on horn flares from line source exits for coaxial comps.

Thanks!

I have built a clone of a popular speaker amp for headphone use, using headphone output transformers. It has worked fine for the last year. I am now trying to re-clone it to a higher model that uses tube regulation. The problem I'm having is trying to determine the value of a couple of resistors for the input tube PSU, using an OD3 regulator. I am going by pictures that the builder posted, but the pix showing them are not clear, and I can't quite make out the stripes. I've diagramed the circuit, with question marks for the resistors in question.

For the resistor at the top of the diagram, the stripes are dark-dark-yellow-gold. I've listed the possible values on the diagram.

For the resistor at the bottom, I can only see the first stripe which is yellow.

Any help will be greatly appreciated.

Slightly cheaper prices on selected Alpair drivers.
Check in at:
https://www.soundimports.eu/en/audio-components/woofers/full-range-woofer/?filter[0]=623322

The standard rubber feet that are attached under the speaker cabinets. Is there some kind of locator plate that the feet can lock into when stacking units? It doesnt need to be deep just enough to stop them moving about (which they do even when rachet strapped together). any ideas? Ive looked before but cant find anything suitable, or even know what they would be called. I've seen that some people use a router to make a sunken area a few mm deep on the top of the cabinet but Im reluctant to do that.

Does anyone have a copy of the Magneplanar wire size chart for each speaker? Thank you!

Can you cool a Class A amp to the point that sound quality is affected?

hi guys, i'm new here.

I have received an old Elkatone leslie-style amp, it has a big solid state amplifier (100 Watts RMS). Unfortunately, it's not working.
When I tried it, there was some hum coming from the speakers. It did output some music trough the tweeter, but not nearly as loud as it should be and with a lot of distortion.
i got some help from a guy on another website. I changed some bad resistors and transistors, but now were stuck.
Here are some pics:




you can see it has 3 IDENTICAL power amplifiers, one for the tweeter and one for each woofer. I made a schematic:


The "jack switch" closes when no speaker is connected. I'm now testing without the speakers connected so the big 10 Ohm resistor acts as load.

As you can see this amp is auto-biasing using 2 diodes (1N3754) placed on the heat sink.

the problem we face now is that the quiescent current through transistor X (about 75-80mA) is not the same as the current through Y (+- 40mA). Also, there is a center voltage of 0,4V-0,5V.

Maybe you guys have a clue on this?

If you need some more information, just ask it i can measure it right here.

I don't know very much about the operation of audio amplifiers, so excuse me if i don't understand everything ;D

PS: sorry for my English, i'm belgian. the translation of some technical words is not easy.

Thanks!

I am a layman in electronic technology, but I love to do it.

I made a DAC with the antique chip TDA1541. The circuit comes from a combination of various machines. I drew a PCB myself.

Coaxial signal is received by CS8412, filter is SAA7220, and DA chip is TDA1541. The analog output part of the circuit comes from the meridian CD player: CD207. The circuit of the meridian looks very unique.

Generally speaking, I like the sound and feeling of nostalgia.

I don't have more professional knowledge, and my ability is limited to making it work normally.

I want to send the circuit diagram of PDF file, but I don't know how to operate it.

I bought a pair of philips 22RH427 and one of the midrange is dead..
I am looking to buy one or a pair

Hi, my name is Giulio and I'm new to this forum, so hello everyone!

I'm starting this thread because I have one of those weird issues which don't happen all the times I use the amplifier, therefore it is difficult to make an accurate diagnosis.

My brother's Copland CTA405 (an integrated tube amp), which is about 7-8 years old but with very little listening hours on its back, has an intermittent problem: quite often, but not always, I hear a very noticeable and persistent volume drop from the left channel after a few minutes of operating (with no additional noises); if I turn the amp off (which is what I normally do when this happens), I hear a hiss with some little cracklings from that same channel, lasting about 3-4 seconds. If I turn the amp on again, the problem often disappears (with no noises when I turn the amp off, this time), or it appears again after some more minutes of listening.

I already excluded a speaker problem (I recently moved to another house with new cables and speakers, with no variations in the problem) or a tube problem (if I invert the left and right preamp or power tubes, the problem is always on the left channel, when present). Bias test point voltages are steady.
As the problem only appears after the amp has warmed up, and it seems to appear less often if I bias a little colder than suggested (41mV vs 45 mV), I suppose it is something related to temperature/overheating. In your opinion, what do I have to check?

Thank you in advance,
Giulio

has anyone else had a play with this evaluation tool??

if i was Celestion or the guy behind it i would be looking for a good place to hide...or fix it...it's totally buggy when it comes to making changes in the already limited parameters, it keeps reverting to the previously entered value which becomes frustrating quick.
as something that seems to be intended as a marketing tool to help consumers select the appropriate product it's a dismal failure....but that's just my opinion.

A friend is keen to buy a DAC with I²S in over HDMI as LVDS. He already has a USB to I²S over HDMI via LVDS, but the pin polarities are flipped for Data and Word Clock. So the DAC will get the Data and Left-Right signal flipped. There's clearly no industry standard 🙁

I understand the I²S word he will use is 32bits with padding of 16bit and 24bit data.

Im keen to use this conundrum to understand a bit about digital encoding if anyone can kindly help me please?

If he plugs his USB-I²S to that DAC with his standard HDMI cable, what will happen?




Will the data + & - polarity flipped matter? Is it just going to cause a one bit delay? A delay that doesn't matter, as the LSB and MSB will be just a padded "0" and will be evenly matched across left and right channels?

Or is it going to cause a loss of one bit depth and a loss of 6dB SNR? If it does, is that a good thing to prevent intersample overs clipping?

Will there be the same music, but just with left and right stereo channels reversed? Easy corrected by just plugging the DAC output cables across channels.

Or do I need to make him a bespoke HDMI cable 🙁

Thanks! 🙂