Hi everyone,

I am looking for a PowDec PTH65301 power supply to repair my Theta Carmen II
CD/DVD player. Do you know where I can buy one?

If you have the schematic, can I have a copy? I will try repair it myself.

Thanks!

Mitch Barnett of Accurate Sound tells us about his journey to become a leading expert in Digital Sound Processing (DSP). Accurate Sound is a remote service using Audiolense, Acourate and Room Eq Wizard (REW)

Accurate Sound Calibration using Digital Sound Processing (DSP)? | Mitch Barnett - YouTube

So just want to share my Eureka moment. Not much of a response on a thread I started about isobaric ESLs. I did not try it because of advisory info on another thread. But this is a bit different. I have a pair of Acoustat Monitor 3 with DD OTL monos. The panels are mounted on the back of the frame structure so there is a 1" set back/recess. I ordered 5/8" thick felt, same medium density as the strips on the backs already to tame resonance. So I cut and covered the entire front side of the panels with felt, filling the recess of each panel/frame recess. I then mounted a second set of panels on the front of the frame, sandwiching the felt. I did not remove the original felt strips on the backs of the second set. Guess what happened when I tapped on the front panels...Nothing! Dead, no resonance to speak of. How silly, right? But here's the trick.. I also hooked up a second set of DD OTLs!! So now there is full damping without loss of output. It's hard to describe just how much better they sound. There's no comparison. The rolled off top end character is gone, mid range is spectacular, that upper bass tubbiness is gone. Sound stage is far more enveloping/depth is just awesome. The sound is so close and intimate it's as if you're right up next to them. This is how they should have been designed in the first place. This tweak is anything but boring.


Just thought I'd mention it.🙂

I was looking at a VIFA application sheet for one of their old tweeters. It was very comprehensive and included a suggestion for an optional LCR network to place across the tweeter to compensate for the resonance (approx 1,500 c/s).
Now I understand that this will reduce the normal res' peak and allow the crossover to "see" a flatter impedance at the drive unit and so perform more closely to its theoretical design goals. It was the next bit that I didn't understand. The sheet goes on to say:

"The load provided by the cross over should be as low as possible at the tweeter resonance frequency. To ensure maximum electrical damping and consequently minimum excursion, it is also recommended to apply a parallel compensation circuit. This is essential for high power output."


So I am clear on its purpose in optimizing the cross over termination but not on how the network reduces the excursion.......
any thoughts would be appreciated.....

And a very "Merry Summer Solstice Situation"* to everyone.
Jonathan

* I am in the Southern hemisphere!

My Aiwa AP-2200 turntable is stuck on 45rpm.

I was playing a 33rpm record and had paused it (pressed down the up/down switch), and when I came back to play it again the record was spinning much faster than it should be. I took the record off and placed a 45rpm one on to see whether that played properly and it did. I then toggled the switch from 33rpm to 45rpm and the speed stayed the same. It's like for some reason the 33rpm setting is playing at 45rpm. I adjusted the fine-tuning rollers on both settings and the 33rpm one still controlled that side, so the switch still does something.

Any ideas?

This is a Gm100 Se Running in class A2. Got a many watts with hight Ht

Diy Amplifier ??????????????????????????

Looking for a few people interested in the Icepower 1200 AS2. We have a couple of confirmations now but need just a few more. The price would be 425+ shipping from MN each. They come in lots of 7 so if anyone interested come on board. I have found fully fleshed out enclosures to complete from Ghent audio. I'll try to link. Also try to attach the datasheet for the 1200.

https://icepower.dk/support/#download-expand

ghentaudio --- DIY Stereo Case for ICEpower 1200AS/700AS

Supplied links, datasheets were too big

Hi, I am not sure when things went wrong but my SE with 45s now sounds very fuzzy. I decided to try a higher voltage than the 275v that it was running with a GZ34S rectifier. So I put in a diode rectifier but the B+ was then 330v so I went back to the GZ34S rectifier. It now sounds very fuzzy. What is strange is the B+ is up at 312V - it seems to have bumped up by 40V. Also the bias isn't very steady, and sometimes one bias goes to 0 while the other doubles. I didn't see any smoke and a quick check of the components didn't reveal anything fried. Any suggestions as to where I should look? Thanks! Henry

Hey everyone,

The wife and I just relocated to the EU. I brought my entire system with me except my DIY DAC (for various logistical reasons).

Now, I need to decide if I'm buying a new DAC or building it myself.

The DAC that I had was based on ANK's DAC. It had an ANK DAC board, a JLsounds USB input, and a tube output stage that was built by a friend of mine. The sound was wonderful, it was natural and dynamic - but it was far from perfect. I can certainly "live" with that sound, but ill be more than happy to get more. I would say that the R2R NOS sounds is definitely my style.

So, here are the options I was thinking about:

• Not build anything and get a Denafrips DAC (probably their entry-level model)
• Get an ANK Kit.
• Build something "from scratch" based on the Soekris.

It's important to note - I have a very limited understanding of electronics. I can assemble anything, I can soldier well and my entire system is DIY (from speakers to tube amps to phono stage to turntable) - but it's only because I can follow the schematics.

In a perfect world, I guess I would have built a Soekris DAC with a tube output of some sort - but I'm concerned that the knowledge base on the Soekris is too technical for me.

So - what's you take here? I would love to get your input.

Thank you!
Tank out.

Hello and thanks for any information on this topic you may have.

I am currently working on building a system around a pair of the Western Electric 555 drivers and I contacted Rod Coleman for help with the power supply for these. Unfortunately, I cannot find any information on the value of inductance of the field coil.

If anyone has access to one of these drivers, or better yet, already has determined this value, please let me know.

Thank you for your time!

12 inch rubber wrap-around speaker gaskets - two for $5CAD


I have lots of them. Purchase quantities and get a better price.

So I'm interested in building HiFiSonix's KX design, but I want to do something a little different and I'm hoping to get a little guidance on my options.

I want to turn them into monoblocks that I locate near the speakers that they are powering. I also want to run the power supplies in separate chassis.

the whole idea stemmed from my desire to build the base schematic, then make an additional mono one for a sub, but then I got to thinking why not make them all monoblocks, further signal separation should be somewhat beneficial or at the least not harmful.

The part I'm going to need a little help with is the power supplies. I'm sure I can just go with some off the shelf ones if I want, but I'm not sure what specs I need for them. I see that it's 26-28VDC or 35VDC in AAB mode, but at how many amps? I would like to build my own PSUs eventually but for now I want to get the amps built and working quickly and somewhat cheaply. Any advice?

I am relocating from California to Texas, and instead of carrying heavy weight 1,800 miles I prefer to sell some stuff, including unfinished projects, on ebay.

Here is the first listing, there will be more.

tube amplifier prototype chassis for parts or to finish - free shipment | eBay

This may be a daft question but I'm going to ask it anyway -

If you have a design for a woofer in an aperiodic box and then double the box size and add another woofer does the aperiodic vent work like a normal vent i.e. you just double the area (or have two of them) keeping the length the same (i.e. the thickness of the box wall) ? Plus within reason can I assume the vent shape is immaterial so long as the area is kept constant ?

By way of an example, take the Seas A26 - 28l volume with aperiodic vent 30mmx220mmx19mm (wood depth) with 12g of stuffing. If I use 2 woofers in a 56l box can I use either two ports the same dimensions or a single port 60mmx220mmx19mm (again keeping the filling density the same, 12g>24g).

Sorry, this may be basic but just wanting to understand how this works.

Hi,

I am trying to use HDMI as input for my ADAU1701 so I can digitally process the audio without the problem of the DSP's internal ADC's.

I have the following:
-. 3E Audio ADAU1701
-. HDMI to I2S Aliexpress board
-. PCM5102 DAC with I2S input.

When I connect the HDMI to I2S directly to the PCM5102 DAC it works perfectly, and it sounds quite good, but when I connect the HDMI to I2S board to my DSP It gets a ton of noise and what I think it's jitter. Unusable.

I presume the problem is in the clocks, so I tried every configuration available in the Register Control on Sigma Studio, and most of them did not make a difference. Setting "Program Length" to 4x and unticking "Master Mode" in "Serial Output" made the sound better but still with noise and jitter.

So, what is the problem and how can I fix it (If possible)?

Maybe the HDMI 2 I2S board work as Master I2S, and the ADAU1701 only supports I2S input as SLAVE?

Or the fact that the clock in the HDMI to I2S board is a 24.00Mhz crystal and the 3E Audio ADAU1701 has a fixed PLL setting for 12.288Mhz?

IDK. Any Suggestion is welcomed as I am planning on getting and HDMI to I2S board with all 8 channels available, but first I want to make it work in stereo.

Cheers

UPDATE1: I just noted that the publication of the PCM5102 DAC has this note: "BCK and DATA marked inverse!When using pls make BCK as DATA , DATA as BCK". So, if in my board they are inverted (but I connected them w/o knowing this), and it does work OK with my HDMItoI2S, maybe this HDMItoI2S board also has the BCK and DATA flipped? I don't think so, but I will try it anyway.

UPDATE2: I don't think the cables are flipped, after thinking a little, when I connect the PCM5102 DAC to my DSP it works perfect, so it's a NO GO.

I can’t seem to find much info on this. If you are building a 3 way active speaker you’ll need 6 speaker cables coming out of the speaker. Do people custom make 6 post binding posts? Do these even exist in a sold set? What is everyone using for active setups?

. Ok so I repair drive. Change out the sn74hc02's on the driver card along with the driver transistors 2n4401-03, voltage regulators are all perfect but the output mosfets still explode. I assume this has to do with the timing of the turning on and off of the high and low side transistors. What is responsible for this?

Looking to buy a Bigbottle MM/MC Hybrid Valve Phonostage PCB. I would prefer an unpopulated board. Please PM me if you have one available.

Cheers,

Bassy

Alpine PDX-1.1000

Anyone know what the part number is for these diodes ?

This amp needs some cleaning not taken care of at all

Hi,

To get full range out of a driver the following is/are typically employed to extend the highs

1) The center of the cone is decoupled at higher frequencies and the cone iis used in breakup mode
2) Stiff dustc cap is used to extend the highs
3) Secondary whizzer cone is used
4) Phase plug is used to break the narrow beam at high frequencies

However, most of the drivers dont seem to focus on achieving constant directivity and polar plots are rarely shown.

So, my question is, can a full range driver be modified as below to get constant directivity. The idea is simple, let the center radiate the highs and as frequency comes down into the mids, have a larger portion of the cone kick in, thereby maintain a constant wavelength to radiating area ratio. Use a 2mm-3mm layer of felt to achieve the damping. Four broad felts are shown in figure but more narrow ones may be needed in practice.

Can the damping be adjusted by trial and error and constant directivity achieved?

Thanks and Regards,
WA

I have a Roksan Kandy that is wired for 230, is it possible to configure it for 120 here in the US? Unfortunately I can't find a schematic.


Hoping it's a dual voltage transformer, there is an unused white coming off the transformer. The transformer is a Toroid, TI-67381A.



From what I understand it would be 2x 115v primaries that are currently wired in series, the white would be used to wire in parallel to get 115v with twice the amps (need larger fuse).



Can I test to see if this is correct?

Are these real?
Anybody bought them?
A number of sellers on EBay with these now, the pictures seem real, but are the parts?
Item numbers..

163702589678
113940521270
113758705087

I don't think that they are real, for reasons that I won't post here.

I'm building an active 3-way in my car.

I now have 10" Pa midbasses, 95-98 dB/W/m. I want to be able to add another pair later. I would want to cross over the 10s at 500Hz or so, can be higher, can be lower.

I am planning on buying the PRV d280ti with a Dayton H07E Waveguide.
I would cross off the PRV at 1,5-2,2kHz.

Now I just need a mid-range in between. Because the 10s are in the doors, so beaming is a problem.
The smaller the better, but I have come to the conclusion that a 6" would be minimum to get 95dB efficiency, or maybe 3x3" on each side.


Now I have a limited budget of 60€ to a max of 100€ for the midranges.


I have 2x200W for the 10s and 4x150W@4Ohm for mids and highs.

I am just planning a single-ended stereo amp using a pair of Hammond 1627SE output transformers I have had around for 20 years.

Going to go with a single KT88 in triode mode.

Cathode bias, 355VDC across the tube, run about 110ma.


Looking for driver ideas, something a little more than the typical.


What do you think of this circuit in front of the KT88?

Aikido push-pull 12SN7.

I would likely add another stage in front to increase the gain.

10 inch cast frame - $8CAD each


12 inch cast frame - $10CAD each


I have a bunch of these - new. Quantity discounts available.

hi I'm looking for a MN2488-OPY-MK transistor as the one in my sony str-dn1030 has let out the magic smoke with a bit of a bang this all happened right as the 8 amp fuse blew

Something I built during the covid quarantine. Marantz 7c clone. Phono stage follows the 7c design. Line stage 12AU7.

Point to point wiring. 90% new parts, including NOS carbon comp and metal film resistors. New power transformers. New tube sockets. New JJ 12AX7 and vintage Eico/Mullard 12AU7 phono stage tubes. New Panasonic polypro caps, new Dearborn polypro caps. WonderCap polypro phono stage outputs. New Angel Cap polypro outputs. Gold RCAs.

Power supply is CLC with dual LR8 regulators. Input stage is L/C filtered. DC heater. Vintage 12AU7s in line stage. Shunt type volume control. Silver coated/Teflon wiring.

The list goes on and on. A lot of excellent parts. Asking price worth the price in parts alone.

Take a look at the pictures. 100% operational.

Asking $250.00 + ship

This one has me befuddled.

Skar RP2000.1 came in with 2 blown n640s on the output side. Pulled all output fets and cleaned up the board. Went to fire up to check for rail voltage and for some strange reason im getting high rail on the low side drains which of course shuts the amp down entirely.

Where would high voltage rail even come close to the low side drains to make a component fail?

I am playing around with a couple of pc mount mic pre input transformers that I want to put into a nickel can and encapsulate. I have the cans and lids, but I am trying to determine what the potting material companies like Jensen and Cinemag use to pot their input transformers. The input transformers I am playing with were wound with #44 awg wire, so I think the potting material is somewhat critical. Too much shrinkage or expansion might compromise the connection of the wire to the terminals. I took the lid off of a Cinemag transformer and the potting was a somewhat translucent clear type of material. I don't think it is epoxy, since it is somewhat soft. I can press my finger nail down firmly into the material and it will leave an indentation. I am not familiar with potting materials, so I thought I would see if anyone knows what the manufacturers are using.

Round terminal cup - two for $5CAD


Square terminal cup - two for $10CAD


I have lots of these. Quantity purchases get better pricing.

So I have a JL Audio that simply keeps power cycling, drawing 2a., then 0 and back again. I pulled all the outputs first and they all test good. So I'm stumped as to what would cause the Amp to fail the start up check.

I usually deal with these car audio hip4080 designs via the car audio forum but most of us are Techs there and i'm hoping for the advice of someone that's designed a few 4080 based full bridge designs. I am attaching the relevant portion of the schematic and a datasheet for the OEM parts. The design is quite old and has been revised a few times but it did work as-is from the factory at one time.

The issue i'm having is i'm losing a lot of parts. The circuit originally uses the RFP40n10 but modern stock behaves abnormally in this circuit. We commonly use IRF3710z and generally don't have too many issues but recently that has changed as well. I'm not sure where changes are being made that's causing this but I can't find anything in the PCNs for the parts. Perhaps I should be looking at PCNs for the hip4080 instead.

I'm hoping someone can take a look at the circuit and suggest a modern MOSFET I can drop into this circuit reliably. The IRF3710z works fine on a resistive load up to 700 watts (My current bench capabilities). When I install it in a vehicle and introduce a 2 ohm reactive load and additional output yield the MOSFETS fail almost instantly. It's growing frustrating. I am using IR/Infineon parts from reliable distributors if that matters.

Full rail voltage is 80v and minimum impedance in 2 ohms. Feedback is pre-filter but I have omitted the feedback portion of the schematic.

Additionally if you can suggest why this may be happening for my own understanding, that would be appreciated. Suggested component changes are also appreciated.

Hello all,

I am am a noob here. So please don't judge too harshly... yet...

I looked around in the older posts and have not found any previous details other than references to my issue so if its OK ill give it a shot here.

I have a pair of B&W CDM1's that seem to have had the ferrofluid dry out and the tweeters are down. Does anyone have any experience/advise for taking them apart/cleaning/re-assembling? or if that is a no-go does anyone know of a suitable replacement tweeter that would fit in the odd-pod it sits in? Perhaps even a car tweeter due to the size? Looking to do a reasonably priced repair and do not mind getting my hands dirty.

Thank You
Brian

hi, so i diged at some posts, but mayby somebody can help me? i got this amplifier, now, awhile ago like 2 years ago it was dismantaled, ant put together, and the thermal pad thats supposted to keep powersuply transistors not shorting out to the case, well i guess it was not allighed properly, i powerd up the amp, played music quite silently, ant boom it was smoking, jumped out disconected, damage was done, fuses did not blow, amp did not go to prottect, just no sound, replaced the transistors, and tested amplifier at home with current limmiting power suply, amplifier is off, it draws current, when its on, draws little bit more, first 3 of 6 transistors seems to be heating up, but sometimes it heats up, others time when testing it seems good, like no sound or so on, but fets doesnt heet up, current its drawing is limited too, im thinking mayby the one, of two transformers is dead? i remember awhile ago it definantly maked some weird noises, now silent, nothing seems be heating up except powersuply transistors, and i dont want to put more current, and make them cook 80+c, dont feel like waiting another month to get them shiped.
so maby somebody have some steps i should follow, or advice?

best regards in advance.

Hello all,
I still have a few Hitachi MosFet's lying around. They are 4x n-channel, 4 p-channel. I understand those are rather old and were used in the mid 80'ies. So I'm thinking to put them to work and build an AMP out of them. Does anybody know a good quality circuit with discrete Parts (no IC, chips - op amp) for them?

Thanks

I'm looking to get a test rig set up where I can do ABX testing of various devices from line level in, to amplifier and (less important) speakers.

My more immediate need is for DSP/DAC and also amplifier comparisons. I notice some differences between two similar pieces of equipment and the logical side of me knows that it can't be *real*. I'd like to prove it to myself with double blind testing. And then work toward generating data in cases where there may be real audible differences (another topic that requires more money than I have at this time).


Google has provided me with a few options:

• AVA ABX Comparator (more than I can afford, pal)
• QSC ABX Comparator (no longer made; unobtanium)
• Record the audio of the various devices via soundcard and then use foobar or the like to do an ABX on the two different audio files (seems like this may be the most likely route for the time being but will be limited by the soundcard's specs)

I have also found a few threads by members here with their own DIY ABX projects but I never see any for sale and, to be honest, I'm not up to the task of building one myself... I'm doing well to solder wire together with my shaky hands.

I realize I haven't provided any specifics at this point but that is due to me not really knowing what my options are. I'd like a remote, automated level matching would be an added bonus but not necessary, and maybe some way of capturing the results automatically to keep me from having to break my session to write something down.


What I'm looking for here is suggestions on other options, or someone with an ABX comparator they want to sell (either DIY or manufactured).

Any help is appreciated.

I've previously used a sealed 50L enclosure for my Seas A26 woofers with great success. But they are obviously quite large.

So I was wondering how small I could possibly go if I implemented some sort of aperiodic loading?

Or will aperiodic loading simply reduce the Q, but not provide lower extension like an actual larger enclosure would?

under
Cybernet SRC-80 Service
unfortunately there are all pages include the schematic filed in jpg and not the usually used pdf.
In the attachment I try to get the schematic more dark for better reading.
But maybe one of the members have it in PDF and higher resolution.

After the issues with my LM3886 (solved in the meantime) I started thinking about a small discrete power amp that is suitable for active speakers. I made the list of what I'd like:
- all discrete, no IC's
- about 10-20W in 8 Ohm, should be plenty for active speakers in a living room
- "good enough", let's say 0.05% distortion or so over power and bandwidth
- stable with enough margin to make it foolproof
- easy to find current components. No matched pairs, ring-emitters, IGBT's or exotic values for resistors or capacitors. Somehow I prefer BJT over FET.
- working from a dual voltage supply
- cheap enough to be an alternative for a chip amp. I will probably be more expensive but it shouldn't be 10x more expensive.

So not the ultimate amp in terms of performance. Does not need to have the least components but let's say the minimum for good function.

The closest I could find is the JLH. The class A working makes it a bit problematic for active speakers. But maybe there is something more recent in class AB around. I have been out of it so long that I probably missed a lot.

Usa or Eu or anywhere.

Dear Members,

I am hoping to sell an unusued kit containing TentLabs Philips CD Pro2 LF VAU1254/31LF kit, XO3.2 reclocker, display & remote. The kit was purchased for DIY High End CD player project that was never undertaken. Are there rules about linking to the internet auction site where this is advertised? I am not a commercial seller.

I would like to know if there are members of the community that source parts from ASWO in Europe .

i have some quality issues that i would like to talk with other members so if you are a client of ASWO please drop me a PM

Thank you

Hi! New to DIYAUDIO, so hoping you'll forgive if this is posted in the wrong place.

Was given a complete SAE system (A501 Amp, P101 Preamp, E101 EQ and T101 tuner) for free (including all the vintage manuals, schematics, service manual).

Pre-Amp has no sound through any output or headphone jack. Powers on and switches all seem to work. Opened it up and looked at the main board. Some glue around the capacitors, but in one section, some significant burning, and looks like someone has already been rooting around in there. See pics attached.

I'm moderately tech savvy, can operate a soldering iron and have a DMM. However, I'd need some handholding to repair, and will ask some dumb questions.

First questions: Repairable? Worth repairing? Or should I sell the pre-amp as is and get what I can for the rest of the system?

Thanks, in advance for your help!

Hi All, First time posting, very long time reader.

I need some assistance in designing a suitable cross over for this driver.

I have a pair of them as a novelty I guess, been sitting in a cupboard for 'awhile'

https://www.beyma.com/speakers/Fichas_Tecnicas/MC115.pdf

My own DATSv3 measurements don't line up with the spec sheet I found above, both drivers measured very closely.

My results are:-

RE=6.131
Fs=727.4hz
Qts=1.49
Qes=1.883
Qms=7.146
Le=0.2372

I've attached screen caps of xsim and the .frd and .zma files

How can I flatten this out?

Thanks in advance.

The flow rate measurement that occurs in an ultrasonic water meter is critical to the accuracy of the meter. All water meters built upon the transit-time ultrasonic principle require some kind of flow calibration. With the deployment of a reference standard flow measurement device, the meter can be calibrated across a specific known flow range. The calibration technique used for the set of measurements taken in this application note to obtain the multipoint compensation curve is based upon an electromagnetic reference flow meter that is traceable to the NIST gravimetric reference system. Calibration of each meter is unique, and usually performed by the meter manufacturer before shipment to the end customer. In the example within, a 22-point compensation curve is created for the meter and then the linear interpolation method is deployed to yield actual flow rates from the data measured by the meter. The accuracy of the newly calibrated meter is then measured by comparing the reference meter flow rate to the meter flow rate in a system where a single flow is measured by both the meter and the reference flow meter.

Hello, has anyone here thought of using one of these to save water for the

environment and put more money in your pocket? I all fairness and for full

disclosure I own maxi and digikey and all electronic companies advertised here on

the forum threads today. Eric Doyle



Why is Calibration Needed?
It has been shown that effects of nonidentical piezoelectric transducers on reciprocity and zero-flow calibration will always be present in a flow meter that uses the transit-time ultrasonic principle for flow measurement2, 3. The dynamic properties of fluids including viscosity influence the distribution of the velocity in the pipe create nonlinear behavior3. Process temperature and pressure lead to mechanical deformation of the spool body1. With proper calibration, the uncertainty of these various effects can be minimized so that the individual meter is made to operate within specifications dictated by various standards bodies worldwide.

Ultrasonic TOF Flow-Measurement Principle
A typical ultrasonic TOF water-flow meter spool body is depicted below in Figure 1.

Typical ultrasonic TOF water-flow meter spool body.Figure 1. Typical ultrasonic TOF water-flow meter spool body.

I sell the following components, all unused, except I2S to PCM and Fifopi. I bought them as spare parts. Fifopi I just bought it from Pistollero, it's not what I need.

Cost shipping from Spain by the buyer.

A) FifoPi: SOLD
B) IsolatorPi + Dop Decoder: € 50
C) FIFO II and Dual XO SOLD
D) SPDIF FIFO: € 40.
E) I2StoPCM € 40.

.

SOLD Aluminium DIY Box / Case for Hi-Fi Audio Amplifier 432x390x150mm

Material Aluminium. Color Silver. Structure Aluminium
Internal width 330, Internal depth 360, Internal height 142.
External 432x390x150mm

New and unused, price in Audiophonics 239€, your price 120€ plus shipping.

100% Aluminium DIY Box / Case for Hi-Fi Audio Amplifier 432x390x150mm - Audiophonics

Hi

I just saw someone having 4 of these for sale. They should be 5" fullrange unit.
I googled for a datasheet, but had no luck. Would anyone have a datasheet for these?
Thinking about playing with a open baffle system with these covering from about 400Hz and up.

The price is $41 (usd) pr unit. Is that too much?

Regards
Jørgen

Hi all,
Anyone has experience using of Bluetooth board Btm875-b on csr8675 chip (link to aliexpress)?
Please help a beginner, unfortunately the seller's answers are very vague.

The board does not provide the connection of any buttons. How to initiate pairing with another device (a source of bluetooth signal)?

Do I understand correctly that if I take the SPDIF version of this board, I can connect Data and Gnd pin of board directly to the coaxial input of the home AV receiver?

Thank in advance.

Hello! I picked up an oldish Onkyo receiver from a thrift shop to use as a garage system. I hooked it up in the store and it seemed like the speakers were working, but when I got it home and set it up it turns out that only one speaker channel is operating at full volume. The other channel is pretty quiet, but will pop up in volume when I crank the volume.

Searching a bit online I found out that relays are a common culprit for this problem and it sounded like it might be possible to remove the relay cover and clean the relays without de-soldering the relay from the board.

So I located the relay and tried to pop the cover off, and I actually pulled the relay off the board breaking a pin in the process. I obviously have no idea what I'm doing. So then I tried to open the relay to look at it and I broke the case that it is in. Inside it looks to me like this thing isn't really meant to be replaced at all.

Is it possible to find a replacement for it, or am I out of luck and just need to scrap this thing? I am looking to the experts to help me figure it out.

I should also say that I'm not even sure if the thing I pulled out is a relay. That is how much of a noob I am. I appreciate any help here, I don't know where to look for a replacement, or how to specify what I need.

I'll see if I can post a picture, but the outside says that it is a Takamisawa unit. It says 24VDC

I have desided to make a quick and simple check list for operational amplifier design.

Please, be kind to comment, review, correct and suggest more things to be included.

What is the pros and cons of CS3310 digital volume control vs. a motorized ALPS potentiometer?

This is for a floor standing studio monitor.

In this example, the 'sweet spot' (between mid and tweeter) is @ 46.5" above floor level... this would be ear level for someone around 6' tall, sitting on a regular computer workstation chair.

The port is a little more than 4' away from the woofer (it can easily be 18" closer to the woofer). Is there any problem with this? Should I move the port closer to the woofer?

Hello everybody!

since I built my tube power amp, I have wanted to build a Phono preamp to obtain a "Transistorless" stereo. I found a design that uses a Single 12AX7 (1/2 per channel), and I wanted to know what everyone thought of it.

I also wanted to know if it was possible to lower the B+ on it, I know that then I would have to play with the Bias in some way, any suggestions?


http://www.bonavolta.ch/hobby/en/audio/1_ecc83.htm

-Moose

A while ago I built a P66 mic pre from ESP. Copied the schematic directly and did my layout in EasyEDA.
I don't have 2N4403 transistors so I'm using BC549 and BC559, both "C" type gain.
Testing it with a signal generator and a scope reveals that a portion of the negative swing is clipped- visually it's about a third of the negative swing.
Reducing the amplitude of the input signal doesn't help- the signal shrinks, but the portion of the signal that's clipped doesn't change.
altering the gain/attenuation pot on the board also doesn't cure the condition. Changing the frequency of the signal doesn't alter the clipping.

I pulled the transistors and verified they work. Their gains are also quite closely matched

I'm at a dead end. Anyone have any idea what's wrong or some advice?

Link to the original ESP project:
Low Noise Balanced Microphone Preamp
attached are images of my schematic (same as ESP P66) and PCB

I need extra voltages for my toroidal transformer. What drawbacks can be happen if I add extra windings (probably 10-15 turns) to secondary without removing top insulation after a proper soldering work? I will use same gauge enamel wire of course.

Going down the rabbit hole and am going to recap my amp and replace the bridge rectifiers with the IXYS units like Jon Sonderberg does. My questions are :
1. Should I replace all the Elna caps on the circuit boards in conjunction with the 4 main caps? The bigger Elna caps are 470 mF 100 V and the little ones are 47 mF 50V.
2. Current Cornell Dubiller power supply caps are 15,000 mF 100V. How high in capacitance should I go to improve this amp even further?

Thanks in advance for any input,

KLC

Does anyone have an idea where it is still possible to buy the original SSM2210 and SSM220 fro AD?

Cleaning up the work bench and have a bunch of PCBs I'm not going to use. Many cases extra from when I had them made in the past ~6 months, others 10+ yrs old...

1 - Quasimodo V4, through hole version - SOLD
2 - SG4 Turntable Controller - SOLD
3 - MA-3D Turntable Motor Amp (QTY 2 Available) - $5/ea
4 - Aleph J Boards - Peter Daniel (QTY 1 Available) - $20/ea
5 - mini-Aleph Boards - BrianGT - SOLD
6 - PSU rev. 2 Boards - BrianGT (QTY 1 Available) - $15/ea
7 - Jeff Young's Dual Rail / Decoupled Stereo First Watt Alternate Power Supply(2oz) (QTY 5 Available) - $8/ea
8 - Jeff Young's Double Bridge Rectifier Board (2oz) (QTY 2 Available) - $2/ea
9 - Edcor PC600/15K - SOLD

Prices are plus shipping, should be $3-7 USPS First Class. US Only sales, thanks. Please PM with interest.

Thanks
Dan

Should the current handling ability of a power supply choke be based on the peak current of the amplifier stages or the quiescent current of the amp stages in a single ended amp?

Hey guys, hopefully someone can help me.


I recently bought an Infinity Kappa 8"
Kappa 800W | More performance. More flexibility.


Using the manual's T/S, I've plugged them into WinISD. When attempting to model the woofer, I get the error "Invalid floating point operation."
I've never seen this error before in the many woofers I've modeled. I tried downloading WinISD Pro Alpha and and get the same error.


I've tried to put in as few (or as many) T/S parameters into WinISD, allowing it to calculate parameters that may vary/differ from the manufacturer, but still get this error.


QES: .460
QMS: 4.0
QTS: (Calculated) .413
FS: 34.5
Xmax: 9.25




Does anyone have any clue what I might be doing wrong? Is this just a one-off woofer with odd T/S parameters?


I'm interested in getting a modeled response so I can see where I should be hitting mechanical limits, etc.

Seems odd & probably missing quite a bit of information.😕

I just got back from a friend's house checking out some old boxes of tubes his son left in his storage shed.

He had the usual assortment of small TV tubes, plus a few WWII era tubes.

But he also had four Western Electric 205D tubes in the original boxes. The one I unpacked looked new, and one of the boxes has never been opened.

I looked on ebay, and they seem quite valuable.

I assume they are used for low power triode audio amplifiers, but I had never run across any of these before.

The dad was willing to just give them to me for free, but I needed to look them up first since I didn't know what they were.

I told him to set them aside and consider selling them on ebay, as it wouldn't be fair to his son for me to just take them for nothing.

Anyhow, can anyone give me any background on how these are used in the audio world?

Hi boys, I'm looking for the schematics of mtx thunder 92001 amplifier.
any of you is in possession ? you may also send it by mail ? joetvanelliclub@gmail.com
thank you to those who will help me .

I been watching the TSE for a while (then the TSE2 came out), but i spent a lot of time contemplating and playing with other topologies and 300b in the meantime. This will be my lil experiment and myth bust.

I used Cascoded LT3092 based CCS and LED string in another 300b amp before. So using a IXYS or sharps IC based CCS should be fine for this.

My other amp is a Cathode biased PSE 2a3 on 5842 drivers, interstages, and ultrasonic AC DHT heaters. i became very familiar with the tubes i wanted to build TSE amp around and it was THE decision point. Ig im in the camp of those who are happy with 5842 and glad it's not E88CC Cca 😱

I'm hoping to subjectively compare with the same tubes the fixed v self bias sound, powerdrive mosfet (not blown away with interstage performance..even NC20 didnt change mind), and maybe upgrade the on board DHT heater to CC+V versus Ultrasonic AC. Gettin away from Quad dht tubes on a daily driver would be a relief. There's only 2 power tubes i want to use right now anyway (a pair of globes with top mica and without) so fixed bias is perfect. ya i have a fixation on globe DHT tubes and maybe when the elrog 2a3 comes out...

After a lot of searching, meets, loaners, auditions i was able to find the new production globe 2a3 power tubes and 5842 drivers with the sound i am looking for and verify it on my other amp. One day hopefully, they will extend the same courtesy to a 45 tube productline and i could try those without building another amp 🙂. It's very difficult to find CC or HFAC DHT heated 45 or 2a3 amp builds that work for both headphone (hd600) AND high efficiency horns.

I love the relatively flat FR extension of the 2a3 tube and it has a little more weight than 45s. You can make them sound tubey or almost SS depending on how you build it, dry or wet (i prefer right in the middle neutral with maybe very slight wetness mMm Ericsson 417a). With the right tubes and setup they can approach 45's speed and nuance with more power and weight behind it. The good and usually $ 2a3 tubes sound like 45 ime.

It'll be a mockup with other spare parts on a PCB holder i can see how it sounds before i encase and put in better beewax and tantulum components. Going to choke it with a C14X to start. Still waiting on a AVC volume controller and heatsink for the default VDC DHT heater.




CC+V DHT heater modules

Stranded Silver Output Transformers


If the concepts of the TSE work out, i would consider rebuilding the whole thing point to point with a dual B+ PSU and 866a rects to match or best the other amp. I'm aiming for less compromised bass performance (without using FB/tertiary FB) offered by fixed bias design and hopefully can match or exceed the dynamics and nuance of the other amp. Makin amps are like box of chocolates..

thinking of a PSU that looks like the Pmillet one

Here's Floyd Toole's comments on the Revel Salon2 vs JBL M2 AVS Forum shootout. He identified two weak links in today's audio:

1) Recording quality.
2) Two Channel Stereo.

He attributed the Salon 2's victory primarily to the first issue. Revel's early off-axis reflections improved the preference ratings because the recordings probably didn't do a good job creating them.

Early reflections are the dominant room interactions above 500 Hz and this may be the most significant difference between these loudspeakers – directivity. They are quite close, but the Salon2 will energize more far-off-axis early reflections than the M2. For laying down tracks and mixing many engineers discourage room reflections, even use “near field” monitors, although mastering engineers often prefer to hear some “room”.

Click to expand...

Later, he explicitly states it.

With the best of today’s loudspeakers, recordings may well be the current “weak link”.

Click to expand...

With regard to two channel stereo, Toole said:

Why doesn’t it sound “real’? Because it can’t. A small number of microphones cannot capture the 3D sound field around performers, and two channels and two loudspeakers of any design cannot reconstruct a realistic sound field. It is the daunting task of recording engineers to do what is possible to deliver a semblance of something real, if that is the goal, or to create an artificial “stereo” variation that is stimulating and entertaining. We need multichannel.

Click to expand...

This means all past recordings are fundamentally flawed. Many are also flawed because the sound engineers had hearing damage due to working in the industry, Toole calls it the occupational hazard.

His post also contains comments particularly useful for DIYers. For example, bass frequencies contribute 30% of sound preference and you get that through multi-subs + room curve equalization. Use microphones to measure the room curve to equalize the low frequency modal region but do NOT use microphones to equalize the room curve in the ray acoustic region above 300-500Hz. Above 300-500Hz you want to measure and equalize the speaker (anechoic or outside or however you can devise) but not the room curve generated by the loudspeaker -- don't equalize the room curve above 300-500Hz; if you have a speaker that measures well above 300-500Hz it will work well in any room relative to other loudspeakers.

These are a collaborative effort of Javad and Jeff Bagby Anyone heard them in person ?

Satori 3 Way using the WO 24-p - 4 the Mr13 P-4 and the TW -29-DN-B-8

Everything you need for a tube amp bench supply:

• 0 to 400 VDC B+ supply, up to 125mA
• 0 to -125V C- (bias) supply
• 6.3 VAC heater supply at 4A
• 12.6VAC heater supply at 2A
• Voltage and current metering on front panel

My reconditioning process:

• Replace all electrolytic capacitors
• Test all other capacitors and replace if necessary
• Test all tubes for shorts, leakage, and emission, and replace if necessary
• Clean all tube sockets, pins, and potentiometers
• Repair or replace any nonfunctional components
• Blow out dust
• Clean exterior
• Replace damaged fasteners
• Test under load
• Calibrate and test output
• Calibrate meters and test for accuracy
• Remove and pack tubes for shipping

Specifics about this unit:

• Used cosmetic condition, stickers and scratches.
• Bias supply adjustment pot is a little "twitchy" in the -16 to -30 volt range. It's steady once it's dialed in. If you want to, it's a simple 50K pot replacement.
• The film capacitors were barely in tolerance, so I replaced all of them as well. There are only 3, if I recall correctly.
• I originally wasn't going to sell this, so I used whatever electrolytics I had on hand. All in spec, of course, just not fancy ones.
• It came to me with 6P3S pass tubes instead of 6L6GC. These run within spec for Vak at any useful B+ voltage, and within dissipation spec unless you're pulling lots of current at very low voltages. I run these in an identical unit without issue.

$200 plus shipping, or trade for a working high quality bench multimeter or VTVM (+/- cash if necessary)

Hi,

I started my first tube amp project and decided to go for a 10W PP.
I have a schematic from the magazine "Elektor".

It look a lot like the Mullard 5-10.

I started ordering all the components, and the transformers just arrived.
They are from Amplimo, 8k 0-4-8 ohm.

Someone noticed me that the feedback resistor+capacitor (C2 and R4) should be connected to the 16ohm side (at least the way they are calculated in this circuit). I first thought the feedback circuit (C2 and R4) should always be connected to the output the speakers use... But no...

So my question is: how can I recalculate the feedback circuit so that I connect this circuit to the 8ohm primary AND my speakers to the 4ohm primary?

I know some basic electrics but not at this level... I would highly appreciate your help.



Thanks!
Regards

Power supply voltage is 10v
Brand new HIP4080A

Pin 1: 18.88v
Pin 2: 11.95v
Pin 3: 0.013v
Pin 4: 0.004v
Pin 5: 0.003v
Pin 6: 5.26v
Pin 7: glitching voltage between 10.4v and 11.05v
Pin 8: 5.14v
Pin 9: 5.14v
Pin 10: 19.08v
Pin 11: 19.08v
Pin 12: 6.23v
Pin 13: a bit variable with an average of 11.6v
Pin 14: 0v
Pin 15: 12v
Pin 16: 12v
Pin 17: 0v
Pin 18: 0v
Pin 19: 6.25v
Pin 20: 19.06v

Hi!

I'd like to get infos about this AMP...

Has anybody this type?
Advisement???

Hey folks!

This is GB for linear regulator PCB. Standard linear regulators can be used such as LM317 and all others that have same pinout. You can use it as preregulator, regulator for your gainclone, preamp, tube heater etc... PCBs would be in black with gold plated holes. PCB size is 50mmx50mm and can accept TO-220 and also TO-3P regulator package. I've made something similar in the past but the PCBs weren't so nice as they would be now in black color, also configuration for symmetrical PSU is now simpler to configure it.
Cost for one PCB would be 2€ and priority shipping(worldwide) would be 3€ for up to 5pcs, I will also post other shipping rates. Add your ID and qty require as indicated.

mravlca

UPDATE 6.4.2015:
Please follow this link for latest version: http://www.diyaudio.com/forums/group-buys/254981-linear-regulator-pcb-lm317-lt1085-lm338-lt1083-5.html#post4283994

Hey there

I'm new to the forum. I hope to help and contribute as much as possible .

They have an amplifier MTX 1501D , which would have replaced the transistors of the power supply by IRF1010E , since according to the datasheet , are of better performance than the 75339p . IRFB42N20D are disconnected.
The amplifier turns on well but the coil of the power supply is noisy , and LED 399 is on, the LED 238 is off.
U1540 voltage is approximately 75V .

Why the power supply coil sounds ?

Thanks and Regards.

Hi all

I'm am looking to upgrade my Musical Fidelity X10D with new capacitors

I have already purchased the items and should arrive in a couple of days, but I noticed the following on the retailers site with regards to the capacitors;

"The line on the label indicates the outermost foil, and should

be connected to the lowest impedance path to ground."

This means that the capacitors have to be installed in a certain direction to take advantage of the outer foil and the benefits it brings. Does anyone know what direction that I should install the capacitors on the circuit board? I know the impedence is higher in the input side and lower on the output according to what I have read about the X10D.

can anyone help?

Hi guys
I try to solve a problem with my Teac CD player
There is some noise in the sound (permanent, no change, comes from speakers) I tried to record - Video
In addition, the spindle motor is not always able to start. Sometimes I have to help him with hand to start rotate
I replaced several capacitors who were with high ESR

Any assumptions will be evaluated.

My brother in law recently passed away and he has these sure in his Tahoe. I can't find anything online and was hoping to get some help here. Thanks in advance.

I've been working on my woodworking skills. I've really gotten into home theater/2-channel audio, and realized that diy is the only way to get truly high-end speakers on a budget. These were 2 Boston Acoustic subs I had in my Dodge truck 10 years ago.
These cabs I calculated with an online subwoofer enclosure calculator. It's made from 3/4" MDF and covered in walnut veneer. I stained it a whitewash stain, and sprayed 3 coats of lacquer.

Hello everybody, with reference to tubes, I am a 67 years old newbie, although I am an experienced digital and microsystems design engineer.

Along with a good friend we decided to build a SE stereo audio amplifier. He is the owner of several pieces of excellent famous brands class A amplifiers, meaning that he knows how they sound. I honestly prefer solid state devices, but, as we are taking all this as a hobby, learning and having fun is the main point here.

So take this as a sincere apology to those experts that this forum is full of, begging for your mercy and patience, which I respect, in my consulting.

When I was almost a child I built some push pull tube audio amps but always following some trusted schematic. I was lucky and enjoyed the ride.

In this case, and many years after, we started by buying these 4 books from Amazon:

Book #1
Book #2
Book #3
Book #4

This was interesting reading but to be honest I found some errors in the amplifier schematic and also typos. I made my own simulation of the circuit using LTspice, and send it to the author, who was very kind to reply and also approve my proposed changes and corrections, most of them because some component values explained in the provided videos, differed with those in the printed text of the books. Grid polarization values and confusing data about number of turns in the output transformer, resistor values in the power supply, etc.

Once I had all these more or less clear, I focused on building the power supply transformer, filter chokes and finally the output transformer. I have access to a friend's professional winding machines, so we built the power transformer and chokes in just one evening. Measured chokes' inductances, they matched those of the calculations.

I found the output transformer procedure quite straightforward and I collected all the calculation in an Excel spreadsheet, that worked fine.

Here are some pictures of transformers and chokes:

Power transformer
Choke view #1
Choke view #2
Output transformer view #1
Output transformer view #2
Output transformer view #3
Output transformer view #4
Pi bobbin
Power supply
Wooden 300B amplifier

I will not reproduce any original images from the books, if somebody is interested it should honor the author by purchasing the books. But I can offer a printout of my own LTspice simulation, that involves some intellectual dedication in putting the pieces together with tube models, some hours working over the circuit errors and specially the output transformer model. The rest of the circuit is pretty conventional, there is nothing new about it. Even more, I deleted the NFB loop that was taken not from the output transformer secondary winding but from near the 300B grid. As I said before, some values shown are not the original ones and I have made corrections. The complete circuit is up and running assembled over a piece of wood and the obtained voltages and signals seem to be normal. They perfectly match the simulation.

Simulation corrected schematic
Speaker output waveform
Simulated frequency and phase response

So then, what's the problem Bob? 😕

Once the output transformer is connected and loaded with an 8 Ohm resistor, the output is only 500 mV. The amplitude measured at the 300B plate falls from a nice large 200 Vpp swing to a poor 37 Vpp. Changing the output resistor value or reconfiguring the secondary taps and windings, the voltage raises. The best I could get was a 7 Vpp signal, with a relatively good frequency response.

Perhaps I made a mistake here - sorry guys for this:

Changing the original spec from a regular multiple layer transformer to a PI winding transformer. If you take a look at the output transformer pictures, I designed and fabricated with my 3D printer, a non standard bobbin former to accomodate 7 PI parallel vertical windings; 3 of them for the primary and 4 for the secondary. This hand made custom transformer complies with the original M4 GOSS lamination size, number of turns and gap specification as shown in the transformer book.

When taken out from the circuit and measured with an LCR meter, the values seem to be normal. 12H for the primary and 116 Ohms resistance. The instrument also shows the calculated impedance that reads around 3K Ohms. Primary and secondary resistance values are also normal and as expected.

But all this measurements are not "in circuit" and there is no DC component at the primary, that should be between 60mA to 100mA.

All the signals from the input up to the 300B grid are nice and perfectly normal. So all the suspicions point to this "innovative" transformer winding probably shorting the plate voltage swing. Perhaps because there may be some special considerations when using PI winding, that in theory should be the best way to get a balanced transformer in terms of equal size windings and improved frquency response.

Secondary windings possible configurations

Before I build another brand new output transformer, I would like to hear some authorized opinion from the experts. Any ideas and help will be, as always, very much appreciated.

I'm going to buy these full range drivers to use them as a "wide" mid but I cannot decide which type of magnet is the better choice. I like the specs on the alnico version but the flexibility on the electro-magnet version is very tempting! Any downsides for the EXC in compare to the AlNiCo?