I am interested in a cd player to use as a transport. I would like the player to have a VAM1250 transport. A unit with a VAM1202 would be ok too.

I have had these sitting in a drawer for a while. I had the front end functional as a preamp. I scavenged the 10uf caps and the JFETs for another project. I populated the complementary output stage with the intent of building the amp but never got around to it. Now I have other projects that I want to complete.

The transformers are 250va 24v Triad units. They are pretty nice compared to the typical Anteks that I have used. New they are around $110 a piece. My intention was to do a dual mono setup which they would be perfect for. Expect along the lines of 30v-32v rails which should get you around 40-50 watts. 5u case would be nice.

So this includes
-BA-3 Front end mostly populated
-2x BA complimentary output stage populated outside of Mosfets (rhthatcher is a good source for those)
-BA complimentary bias boards populated
-2x Triad 24vac ~10.5 amp transformers

The whole lot is $175 plus shipping.

I'd like to improve my DAC psu. I'm not talking about the analog stage, just the CS4398 chip on the board. I like it a lot.

Is it important to have dual regulated psu? Currently the DAC chip is served by two +V independent LM317 regulated rails.

Questions: There would be any benefit replacing them with two independent dual +V/-V regulated rails. If yes, could you suggest some pcb/kit?

Hi everyone .
Can anyone figure out how this system works?
the principle is the optical one but I would like to know more and with the translation I don't understand anything.
https://patentimages.storage.googleapis.com/95/14/71/85225e1551d882/US4207430.pdf

Can I ask the thoughts on the pros vs cons on the match of the td10m vs td12m in regards to the best match to the tpl 200h

2way vs 3 way
Sealed vs ported
Crossover points
Beaming
Etc

Thanks

I've been experimenting with a tube preamp designed to add some tube "color" to a solid state system, and as part of this, tested the effects of an input potentiometer vs an output potentiometer, and where you place the actual volume control depends on what you are looking for the pre-amp to do.


One interesting thing I learned was: there was a lot of conjecture on some forums about the impact a potentiometer placed on the output would have on the frequency response. Several people insisted that with the pot on the output, there would be large changes in the frequency response at different volume settings. After building the amp and testing it, this output pot placement actually had no impact on the frequency response at any setting.

Anyway here is a short video showing the effects on distortion, testing with an actual tube pre-amp, of input vs output potentiometers.

Login to view embedded media

best offer

I think I have 3 -- Peerless 5-1/4" woofer 830343 - 4 ohm - SHIELDED -- CARVER 5.2 5.1 - 5.25
And then maybe 2 shielded versions

The cone tweeters and dome tweeters I have quite a few.

Hello fellow DIYers
I built an RH84 v2 amp, the amp by itself is working fine, it is quiet, no buzz no hums and very little hissing which is not much audible when it's playing something.
I decided to use the RH84 to power the HF section of my active speakers and leave the lower freqs to my trusty Hypex, both amps (RH84 and the Hypex) work fine with no issue on their own, but when I turned them on together both amp start buzzing load, if I turn either off the buzzing will stop but apparently they are not happy working together, sounds like grounding issue ? any ideas ?

Good morning. First time writing here. I have a big big problem choosing a 10 inch midbass model and i explain you why. i need to put 4 10 inch midwoofer in a really really compact box (60 liter). it will be used as a portable box in some king of car audio application, with 2 compression drivers (faital pro hf108). The goal is a 2 way that can be as loud as possible. Someone can help me?

Since I am (apparently) still able to get a few of the old 2SA1349 and 2SC3381 duals, I'd like to ask the forum for more information about these parts and their use. Borbely used them in the input of one of his amplifiers, a fully DC coupled one iirc. Since I am leaning towards BJT single diff input in my amplifiers, I am considering using these.
What I don't know is how they compare to something like a MAT dual or LM394, or the SSM replacement. These use dozens (or maybe hundreds?) of BJTs in parallel with interleaved construction, like a chess board, to achieve matching. Do the Toshiba parts use this technique?

Are the duals an improvement over a pair of selected BJTs (lab matched beta and vbe)?

Thanks,
Alex

4SALE: 5x Tachyonix 6116m

This is a stand-alone controller for the Micro Analog Systems MAS6116 Stereo Digital Volume Control.
It converts an input voltage to the serial bus data needed to controll the MAS6116 digital potentiometer.
You just have to connect the wiper of a (mono) potentiometer to the input of the IC and it translates the 0V...5V to the corrsponding serial data for the volume controller.

I purchased them directely from the manufacturer but they never found the way in a project. So they have never been used or tested.

Price: 5€/each + shipping



Datasheet and example circuit (source unknown) in annex (the english datasheet is only as a reference, as is shows another version of the IC, the correct pinout is in the japanese version)

Hi,
I want to add a potentiometer for volume control to the tube pre amp in the schematic. What should the value of the potentiometer be? Will I have a problem?

Looking for one of those, preferrably in the UK.

Audio has been my hobby since early 70´s, but I have been tinkering last 5 years mostly with tube gear. Last weekend I bought HK Citation 12, as it was amplifier I could not afford in mid 70´s. I also remember Nelson Pass Citation 12 mods from 1981 AA.

However I have some questions about this topic. Maybe Nelson or other fellow members have useful information available?

It seems that here are two Pass Citation 12 versions available. I usually think that simpler is better, but now I have wondered if the original or later complementary version is way to go? Do complementary FETs have so much lower capacitance that driver stage will become unnecessary? Also modern day replacements would be appriciated for MPSL51, MPSL01, IFR100, IFR130, IFR9130.

Nelson specified usual passive components to be used. However when I did Quad 22/II combo rebuild few years ago, I replaced all carbon comp and two precision carbon film resistors from 22 line stage with better spec metal film resistors as suggested. This produced inferior sound quality. When I later reassembled 22 with original parts, pair by pair, I discovered that original carbon comp and carbon films produced better sound at anode and grid circuits. However MF:s were OK in low impedance cathode and feedback circuits.

I do not believe in snake oil, but it seems that also passive parts do have effect on sound quality. It would be nice to know which resistor types Nelson would use today in different Citation 12 locations. This would be interesting, as there is so much high spec close tolerance hype here. It was so refressing to read Nelsons remark about 10% wirewounds to be perfect for L300 crossovers.

Best Regards

Kimmo Salminen

I have two subwoofers which will be described as follows:

The first sub
1. closed enclosure
2. 8" driver
3. fb = 56 Hz

The second sub
1. passive radiator
2. 5.25" active driver
3. 8" passive driver
4. fb= 28 Hz

I wonder if these two subs are played simultaneously, will it cause phase differences, resulting in dips or peaks in frequency response due to phase interference at some frequencies since they have different resonance frequencies (fb)?

Hi! From my understanding, passive DIs are generally preferred on stage if using an active instrument (keyboard, active bass or a buffered output) due to total isolation from the console (which might have phantom accidentally switched on or some other stray voltage). Now my curiosity is the following:

Does the output of an active DI offer protection against high stray voltages (not sure about how common these are but just in case), such that this voltage is not seen at the input? I believe that the active DI output offers a degree of protection against it being already powered and having phantom power available on the XLR output but cannot withstand high voltages (that are unsafe)?

Also, is a passive DI better at offering noise-free operation? Generally the ground lift option and transformer isolation go hand in hand, but it seems that ground lift is also possible when not having transformer isolation.

Tia!

Hi There

I have a Perreaux r200i amplifier

I noticed on the left channel they is a hum coming from the midrange speaker audible only form a few inches away .. but one you notice it// It cant be unnoticed if you know what I mean!! 😒

Unaffected by volume control , source selection ,or source connection high quality caps replaced 6 years ago but have been told they may be the problem attached is a recording from my iphone at 1 cm away from the speaker.. ignore the wind noise picked up..

The same noise can be heard from the right channel also.. but to a much less extent ( only in dead silent environment with ear almost touching the speaker)

What’s your thoughts?
I know technically not diy but I want to fiy fix it?
Cheers for any help

I have been scouring the internet for published horn system plans for myself, the one that seems intriguing is Kimmo Saunisto's KS-1804 mk2. The cardioid concept is interesting. The issue being the Stereolab horns that were used in the original design aren't available anymore. Could someone suggest what can be used as a direct replacement?

Hello,

I have thought of taking up the project of building my own DIY loudspeakers, I'm looking around because I've been using some Radiotehnika 35 AC-1 and I'm seeking something that still has the heavy booms (well more of it) of the AC-1's but something that maintains more crisp highs and a less distorted sound at loud volumes. I've been looking around the internet and found that Paul Carmody's "Tarkus" has been well appreciated throughout the years. However, I don't think the Tarkus will fulfill the satisfaction im looking for as they are pretty similar to the AC-1's (Driver wise). I am not a proffesional in audio at all but have a beginner understanding of speakers and sound. Hence, I come here to ask for your help so I don't start building something I will be dissapointed with. This is what I've been thinking of: 3-Way speakers, can be used with 8 ohm amplifier safely, loud, floorstanding, drivers and materials that are available in Europe (so I don't have to pay expensive import fees), somewhat easy to follow instructions such as already made schematics for crossovers, under 750 Euro, cabinet dimensions and sound as described before. Please let me know if this is possible in the price range and if it is worth it.

Thanks, Tadas

Possible name and sufficient wattage and what not to set it up? Thanks in advance.

Hello guys

So recently I started designing my first set of speakers and amp for them.
Creating two-way speaker from woofer that is 4 ohm and RMS 40W the same impedance and power handling tweeter with a crossover would make the speaker 2 ohm. (I already chose the drivers and I would very like to not search for others)

For the amp I would like to choose prebuilt amp module with DSP like something Sure Electronics have to offer.
Either 2X50W @ 4ohm or 4x100W @ 4ohm

Now the question is how to connect them and not burn any electronics. These are my ideas so far:

1. Use the more powerful amplifier and connect a speaker to 2 outputs at the same time (in my head it should increase power and reduce current draw from each out. I just thought of this writing the post)
2. Connect 2 ohm speakers straight to 4 ohm outputs as I would probably never even use full power output and maybe decrease maximum power output with software tweaks on ADAU1701 DSP that is soldered onto the amp.
3. Add a resistor in series with the speaker either in the amp itself or the back of the speaker (I suppose putting it in a speaker would raise the temperature to the one in the core of the sun and beyond after some time). How would a resistor affect the frequency curve?
4. I know that wiring more drivers in series will increase the impedance but this is not an option as I would like this to be rather budget project.

Really looking forward to reading your experienced answers because this problem is bugging me for quite some time and I don't seem to find any concrete answers online.
Thanks 🙂

Parts that I have in mind:
Sure Electronics AA-JA33286 (4x100W @ 4ohm)
Sure Electronics AA-JA32173 (2x50W @ 4ohm)
Woofer: https://www.soundimports.eu/en/tang-band-w5-1138smf.html
Tweeter: https://www.soundimports.eu/en/dayton-audio-rst28f-4.html

New and shiny toys!

I played around with 4fe32 and 4fe35 and they are quite nice once the breakup/resonance is dealt with. And if one keep the excursion down by not trying to reproduce the lowest frequencies they can play quite loud!
So I have high hopes for this new little driver.

The frame and gasket is the same as the 4fe32 I believe, but there is a new cone material and dust cap shape.

Don’t get any high hopes for quick updates on any project. This is only a teaser.

https://faitalpro.com/en/products/LF_Loudspeakers/product_details/index.php?id=401005105

https://en.toutlehautparleur.com/speaker-faitalpro-4fe42-8-ohm-4-inch.html

I have a non-working PSB series200 subwoofer, I was under the impression that PSB did not give out service manuals after reading the thread on PSB Alpha Subsonic1 but I sent them an email anyway and was surprised to find a return email two days later with the S.M. attachment.

I just bought the Jamo Concert 11 speakers for a good deal only to find out that one of the SEAS midranges was on it's way out. I don't think that the seller knew. Anyways, has anyone figured out a good replacement for them?

The part number is:
20525 W17E-JAM SEAS

It is a magnesium SEAS driver. Pretty nice actually. Cabinets are great etc. I don't want to end up having to part them out. The speaker that works sounds great.

The midrange failed in the weirdest way. The voice coil came off of the cone. Also, the magnesium cone was corroded even though the rest of the speaker is in perfect condition. I am surprised to see those issues on such nice drivers.

Let me know if you know of a good replacement or happen to have one!

Hello,
For my next speaker project, I was thinking of sandwiching a thin layer of rubber between 2 18mm pieces of Baltic Birch and use it to make the baffles to isolate it from the enclosure.
Has anyone tried this? Would I gain anything?

Talk me outta this bad idea the $ is a non issue. Things to know fully active every driver has a amp and dsp with upto 65k taps per driver. Delay is no problem I already use my plex server to delay hdmi when watching movies.
Drivers :
1x Bliesma 25b + 5 inch augerpro waveguide 4k+
2x bliesma 74b 400 to 1k and 400 -4k
4x LOM165_vPA-H-8 60 to 400 ported or different ideas are welcome ( can't look ugly this is strictly a wife approved speaker)

All xo at 98 or higher dB brick walls also doable.

T-M ctc is 3.5"
M-T-M ctc is 7"
W ctc is undecided and side mounted woofers are not out of the question.
General idea is spacing of 1 with steep filters no comb no lob in theory ehh.
Box will be kurfed vennerd mdf 3" roundover of 2" thick walls cld of 48"x 12" x 17".

Goal 95db from xx up crossed to 2x uxl-18s that will be built like a modern media center.

Cardioid ? I did this active in my other speaker.
Correcting group delay of the ported mids ?
The woofers seem to be peaky would it be better to use 3 different ported hz ie 55 75 85 ?

I hope to have time to learn VituixCAD next week.

Thanks to Nelson, we enjoy listening to our amps as people who have somehow reached the great class a amp sound. but from now on, our new diyer friends will not be able to reach some components very easily or they will not want to enter into complex works. My dear friend Erdal, with the precision of this, modified aleph by making it simpler, more compact and cheaper, and concluded it successfully. later on, he will also participate in this title and will provide you with more detailed information. Let me just open the title with a few photos and videos. cheers.

Laying in my drawer for more than a decade!

I have 2 of each left.

Sending at cost in padded envelopes (max one of each stereo-PCB per member) at 10 EUR not traceable and 20 EUR traceable.

With the Hypnotize (check here) I will throw in the bag some Alps pot PCBs as well.

Greetings!

I am looking for a DSP unit with typical ins and outs ( 2 in 6 out or similar ).

However, I would like to experiment with manipulating harmonic distortion and specifically, adding it in different places throughout the frequency range.

Are there DSP units that allow that? if not, how can I experiment with this?

Thanks!

…and if so is there a particular replacement part that is better, and/or any other tips for me please? Many thanks.

Hello Everyone,

I'm new on here. a long time reader .. Looking to learn and exchange ideas.

Thanks

In stead of the standard ‘offset driver’ To kill that second pipe resonance?
(I’m just being a nerd-geek)

the 3000cm2(90 liters) @30 cm and 500cm2 42cm port (~50 hz in the green graph )

verses the 3000cm2 offset at (~1/3) 107cm in 300total.

ADAU1701 is cheap, easy to use and VERY powerful with the use of SigmaStudio... but it's ADC and DAC are garbage...

Isn't there any "expansion" board that can implement a better ADC and DAC for the ADAU1701 using I2S? Maybe not SOTA, but closer to the 100db THD+N...

I know you can connect another DAC's (I've done it) but haven't tried I2S ADC, and I surely don't know which boards are correctly designed. In Aliexpress you can find I2S ADC and their specs are as follows:


Imagine an expansion board to connect THIS ADAU 1701 and add a PCM1802 ADC and a reasonable DAC. The whole point would be to use the ADAU1701 for active 3 way speakers, although performance may not be close to HypeX Fusion amps, but it should be very cost effective and the performance would be around sub USD$300 active speakers.

Do you know if this expansion board exists? Is there anyone that could properly design it and measure it?

Cheers.

Hello. Is there a good full range driver for pensil (or similar) and SLOB (https://www.diyaudio.com/community/threads/pass-slob-build-discussion.300952/post-7162504)? I'm eyeing the Lii Audio Fast 8s since I've seen them in both.

Ideally I would build the horn first. As time and money and crossover understanding grows I could transfer the driver to the SLOB but I'm not opposed to picking up an Alpair and shelving the SLOB for now. It'd be nice to play both sides to the middle though.

Really just want to express my love for the Iron Pre in my rig peace. Just have to think there are others of my ilk. Peace

I think I could use 2 midranges
Silver leads , cast frame
roughly 50 cm^2
8-16 ohm nominal impedance

Any one have some they want to get rid of?
NH USA 03063 is my location

Please recommend some screws that I can use for 4 pin XLR Neutrik connector. https://uk.farnell.com/neutrik/nc4fd-lx-b/socket-xlr-black-4pole/dp/1390122

Ideally something like this:

Bag of 12 new ADCOM fuseholder inserts as used in GFA-545, 555, 555II, 565, 585, etc. Left over inventory from when I did authorized repair for them. Make a reasonable offer. Will not separate. Shipping alone will be $7.00 for First Class mail. Please pm if interested.

Total of six devices. Came out of a working amp. $30+shipping for two of the boards and I'll throw in the third for free. That should guarantee you get two working boards but more likely three 🙂

They had 10,000 UF caps that I scavenged for another project. They seem someone would be interested in this for the LM3886 devices.

How Pa selects the front panel color for his FW products? Is the secret in these pages and I failed to find it?

Anyone knows or want to guess? Please tell me or I will lose my sleep.

And what if Pa would gift all of them (except SITs) to you but you could only choose one color? Which one would you pick?

Aleph J - Silver

F1 - Black
F2 - ?
F3 - Silver
F4 - Black
F5 - Silver
F6 - Black
F7 - Silver
F8 - Black

M2 - Black

J2 - Silver

SIT-1 - Black
SIT-2 - Black
SIT-3 - Black
SIT-4 - Black

Any suggestion would by helpful to manage the above connections.

This is the diagram so far. I'm wondering especially about
connecting the ZOOM R8 into this configuration. ie. can I connect the R8 to the interface via usb by using a usb splitter at the interface end?
How would I work it if I want to use the c3000 mic to record with the Zoom and at another time record into my DAW in the PC?
Thanks!

Hello diyers,

I'm looking to upgrade the diode FFSP0865A (datasheet) to give some more headroom in the SMPS power supply and keep things cooler and more stable under higher loads.
I've found an infineon and it seems pretty decent as upgrade, the IDH20G120C5XKSA1 (datasheet)

Any other suggestion? Don't mind paying a little bit more for a better part, no price limit.

Thanks for the help!

Hi, recently I restored a Yamaha YP-D4 direct drive turntable. From that grey plastic "veneer" I made it to a piano black. All great, the turntable is all set up.
The problem is that the strobe is not spot on but it wobbles a little left and right.
I set the motor control as in the manual but I cannot make it to be spot on.
Anyone, any ideas ?
Thanks.

I'm attaching the service manual and a speed test done with a phone app.

Good day to everyone. I was working on an Stetsom EX3000EQ whose ouput blue caps are burned. This caps are connected to the output terminal of the mono amp. I got the same amp with my colleague for comparison, Can anybody Please tell me how to read and the values of this 4 blue capacitors? Thank you and more power.

T-reg kit, 2 x "main" boards, 2 x (built) tube-reg-pcb, 1 x ss-reg pcb
selling all, including construction papers.

Open for a good offer, or, can trade for 2 x good nos 6922 tubes...

First time, long time. Err, a couple years.

I’ve been working thru some kits and vintage buys. Starting to get into things I need to understand instead of follow directions. Slowly. Fair amount of gear when I think about it: akitika amp, b1 korg, bugle 2, elekit preamp. Homemade tiny radials, econowaved advent 2’s, Jbl L86 & L40, ads L300c. Sony str-6055, HK 330b. Dual 1229q, pioneer pl-518, rega rp1.

I borrowed some Fostex blh and have been lurking around the full range board lately.

Also picked up two tokin 2sk180s a while back and need to figure out how to implement them. Recently grabbed Aleph J boards that I hope will help to better understand amps.

Dear All,

After bread-boarding my a design I had been simulating for months rather successfully the time has arrived to start the PCB layout. To minimize PSU impedance I opted to place the PSU components right by the OPS on the same board with a ground plane as return path for reservoir and capacitor caps.
This arrangement makes sense intuitively: (load current from speaker to caps indicated by green arrows and Charging current by Red) Is this okay?


However I struggle to understand how to arrange the rectifiers, reservoir caps and negative speaker terminal. My understanding is that the charging currents between the rectifier and capacitors cause an AC voltage between them which may be imposed on the negative speaker terminal (speaker ground), causing audible hum. The speaker terminal draws its current from the reservoir caps which in turn draw current from the rectifier. Does this mean that when the speaker terminal and capacitor share a path to the rectifier hum may be created?

Next there's the matter of where to connect (small)signal ground. My plan is to connect it right at the negative speaker terminal. My reasoning being that when there is an AC voltage between signal ground and speaker ground hum is created.

Simulated PSRR is over 140dB so hum shouldn't be injected through the voltage rails. PCB layout will make or break it, I feel my reasoning above might be incorrect. Please feel free to correct me but most of all do tell me how the PSU/OPS layout may be improved.

Long story short, is this layout fine or should it be reworked?

Much thanks and Cheers!

Ruben

Hi diyAudio: I have a question about modifying a 3-way crossover, if it becomes necessary.

I’m interested in building a 3-way DIY speaker kit. The components and design come from a reputable supplier and designer. My concern is that the voicing of the loudspeaker might not be to my liking. My current 2-way speakers, which I like a lot, have a “Harman curve” with a slight emphasis in the bass and a de-emphasis in the treble. The off-axis response is also good.

I’ve heard expensive commercial speakers that I didn't particularly like. So this potential issue is one of preference not a criticism of the designer. The problem that we all recognize is that you don’t know how things are going to turn out until you’re done. I did a DIY speaker project 20 years ago and came up short of expectations because of the crossover.

@giralfino has stated that a flat on-axis frequency response doesn’t necessarily make for a good speaker. Fair enough. Is there anything you can do about that situation besides rototilling the whole crossover design and starting over?

I know some will suggest an active crossover, which makes a lot of sense, especially if I had a streaming front end using Audiolense or JRiver. However, I don’t. I’m old school and just listen to CD’s. And I have a lot of them. Plus, I like the idea of set and forget.

I’m on my 2nd act, this time as a furniture maker (unpaid ;-). This project isn’t about saving money but answering the Siren’s song.

Can someone help me understand the physics behind why adding mass to a driver increases Qts? In my mind, it makes more sense that adding mass would lower Fs, and smoothen out the resonance peak. This is indicative of dampening being increased right? Which is the opposite of what increasing Qts does? So why would adding mass increase Qts?

Hi All,

Is anyone facing similar issue?

Here is story:

I'm using BTM571 (QCC5171) module in my design and testing TWS set of two modules connecting to different smartphones.
The firmware is running pretty standard (earbud project) from SDK almost w/o modification.

The TWS set works just fine with Pixel 4a and existing antenna implementation (Taoglas FXP75)- see HW details shown below.
The range is about 20 meters radius from Pixel 4a which is sufficient for me.

The same TWS set and antenna works just worse with iPhone 12.
Highly difficult pair and connect on short distance. While connected it works only at distance 3-4 feet and iPhone is breaking connection.

I changed antenna on to much more bigger (FXP74). It helps a bit, but "connectivity problem ratio" is still the same.
Working excellent with Pixel 4a at long distance (30-40 meters), while iPhone connectivity breaks at 10 meters and have pairing and connecting issue at any distance.

Both audio codecs works - AptX for Pixel 4a and AAC for iPhone.

I'm suspecting something is wrong with Bluetooth RF configuration or BT pairing protocol needs to be adjusted specifically for iOS?
Is any specific .htf config settings related radio?

Appreciated for the help!

My speaker manual suggests to build the passive crossover by using a capacitor with this spec: "80uf Non-polar Audio Capacitor, 50V Working Voltage".

As I search for capacitors available on the market, they have two voltage parameters; VDC and VAC. Could anybody advise me does the "50V Working Voltage" mean VDC or VAC?

Will it be fine to use a 33uF 35VAC/100VDC in parallel with a 47uF 35VAC/100VDC to form a 80uF 50V Working Voltage?

Dear audiophiles and electronic enthusiasts
I have a rega mira 3 and a speaker set My rega just Humm and does not give any response for none of the inputs . The volume knob works and input selector works fine also.
Even I check the left and right side terminals with my ohmmeter I read 4 ohms each .(speakers not connected) and the worst the amplifier heatsink becomes hot by the time.
Any suggestions or check point for my issue ?
thanks in advance

I have a brand new, never used TWSDAC-LT board (thin film resistor version). I purchased from Andrea recently and will not be using for the time being. US shipping is preferred.

Hello everyone.

I would like some advice on replacing the opamp in the headphone amplifier that you can find at this link:

https://bsproj.it/ba120/

My needs are:

Single channel

Possibly FET input or alternatively bipolar input with very low offset that can be used in this specific application without the need to create an offset adjustment circuit.

Power supply +- 18V or more.

Very transparent, open and linear sound, rich in detail, harmonics and spatiality, with solid, deep and damped basses. I don't like the veiled and soft sound on the high frequencies.


Thanks in advance for your suggestions.

Andrew

I hope me asking a question on how to avoid gaining audio knowledge is not too un-fanatic, and it is not meant to belittle your (frighteningly complex) hobby.
So.

I like 3D printing.
And I would like to play around with different (smallish, because of build volume restrictions) enclosure designs until I find the nicest one for my home.
And I would like to do this without getting into yet another hobby, if at all possible ( ... at least I can try). So I would like to bypass all the knowledge-intensive parts (measuring a driver, simulating it with different volumes and designs, evaluating response curves and deciding which one corresponds to ´nice´sound ..... ), if at all possible.

So my question is :

Can an audio-fanatic distill its knowledge into a set of parameters that sufficiently describe an enclosure so that it will at least sound ´okay´?

I hope that something like the following is possible:

- Take well-known driver a
- Put it in a volume x
- Put in a port of area y and length z
- make sure that no two walls are more than l cm apart and/or parallel to each other
-> And whatever you do, you will get ´good enough´ sound down to soandso Hz.

This would allow me to happily try out shapes without fearing that it is utter nonsense from the beginning.

Would this be possible - or is enclosure design far too complex to be distilled down to a finite set of parameters like in my example ? And if yes, which parameters would be neccessary?

Thanks for your time !

For sale is brand new Par-Metal 20-12123A Enclosure Gold/Clear alodine finish for EMI shield. The case is without front and rear panels.

$75 + shipping or please make an offer.

Most of my digital gear already has BNC s/pdif connectors. There are couple exceptions, however, and it seems to make sense to just replace the RCA connectors with proper 75 ohm BNC sockets. I'm tired of wondering what problems are introduced by RCA => BNC adapters, BNC => RCA cables and other dubious kludges. But I wonder if the equipment designers did anything special to accommodate the RCA sockets in terms of impedance or god-knows-what else?

So: Is there any reason not to just go ahead and replace the RCA connectors with BNC's? Is there any special lead dressing or positioning with the BNC sockets that I ought to be aware of? special wire from BNC to PC board?



The gear in question is an M-Audio CO3 (source selector and s/pdif <==> AES/SBU converter) and BluSound Node 2i. Maybe also Asus Xonar Essence STX sound card.

Thanks for any comments.

Here are the main topics I intend to discuss:

• Sweet Spot Measurements of the Tokin 2SK182ES SIT.
• The SIT mu follower and its circuit relationships. I found some very simple equations describing the behavior of the mu follower.
• My build of an amplifier similar to the FirstWatt SIT-2.

Hey guys,
currently I am designing a crossover and stumbled upon a hurdle, that I can't find specific opinions on.
I only found out about the consensus that direct sound power is not to be neglected.
Please look at the pictures provided to understand my problem.
I designed a crossover that is quite flat on-axis but has quite a dip in Sound-Power and In-Room-Response



Now, when I adjust the inductor in the tweeter, Sound-Power, In-Room-Response and even directivity enhance by quite a bit but the general response isn't as flat anymore.


Is there a general design consensus about what to do in a case like this? Might a slight bump in crossover region even be preferred?
Thanks for all help upfront

I am refurbishing a Teac reel to reel and one of the CR units (400VAC, 0.1uF cap + 120R resistor) has a lead broken off and I need to replace it. I believe they are spark arrestors/snubbers. This particular one is on one of the reel motors.
I have 630V film caps and 1W, 120R resistors. Can I just put them in series and use that to replace it?

Hello guys,

My journey here started a few years ago. Like many of you I started with an Aleph J.

Just from the beginning one of the channels had an issue with the input jfets and at that time a very generous user aroud here( Buzzforb ) offered to send me 2 matched quartets of j74. I replaced what I had with one of his quartets and the Js played for 10 years.

Recently I encountered also Nelson’s generosity which beside sharing schematics and ideas all these years he first offered some matched lu1014 and I got 3 pairs. After that he offered also a matched pair of sjep jfets. And if this wasn’t already enough another friend that I met here offered another pair of sjeps and some other mosfets. Today I received another gift from a nice guy around here.

So in one word… I don’t know if I can ever repay all this generosity in another way than doing something similar myself.

Not long ago I built 4 output stages that I used to replace the Js. Initially I went bridged but when I realized that it’s not what I really search for, I removed one OS from each amp and went single ended. So the 2 unused ones went for sale.
Initially I went with mosfets in the OS but then I wanted to try the lu1014 jfets from Nelson so I drawn a second revision for the pcbs.

Today I changed my mind, I don’t want to give them away for money but for free, you have to pay only the shipping.

The entire story can be found in The marriage thread.

There are a few conditions that you have to meet:
-1year since you have the account here
-since this is a giveaway only for the output stage you need a front end, the winner will need to show a photo with the fe he wants to use with these.
-only one entry per user
-the mounting holes are not UMS so you will need to be able to drill them
-you can seel them if you want but not this year!


How it'll work: (I copied this part from Cody give away thread)
To enter, just copy the list of entrants, paste into a new comment, add your DIYA username to the bottom of that list and post. In 48 hours or so, I'll make a comment saying that entries are closed. I'll take the final list of entrants, paste them into an online randomizer, and the name that appears in the top (#1) position will be the winner. The winner will need to post the pics of the fe here and send a me pm with his shipping details.

Good luck!

Hi all,

I would like to know the resistor value R90. It is connected between secondary ground and primary ground. Thank you.

Hello community,
I would be interested to know if there are any advantages or disadvantages when using 2 smaller chassis to one large one?

Let's say I would take 2 Scanspeak 22W/8851T00 instead of one 26W/8861T00.

I've had my 332 for years and been very happy with it. However, while recently moving my system around one of the speaker connector wing nuts snapped off. Very annoying. This leads to several questions.....

• I'm going to try to get a replacement connector from ML but I'm not holding my breath. Anybody know of a alternative source?
• Getting the 332 disassembled sufficient to replace the connector looks like a bear of a job. I did, however, find a manual for the 331 (attached). Does anybody know how similar they are to the extent that the 331 manual would apply enough to get the 332 apart? My impression is that layout & design are extremely similar apart from power transformer, caps, output devices.
• The 332 was recapped about 8 years ago and seems to work perfectly. OTOH, if it's all taken apart it might make sense to recap it on principle. I'm confident that I could do the job mechanically, but not so sure about any adjustments, bias settings etc. So there may be merit in "if it ain't broke, don't..."

Any thoughts on all this would be very welcome. Thanks in advance and cheers,

Hi guys,
ages since I'm not asking stupid questions here... Anyway, I've recently got an oldie DCD-980. It was reading CDs very fast and after a quick listening seemed promising.

So I initially looked for some quick&dirty pieces of advice on upgrading Denon players. I clipped off the ceramic caps and muting transistors in the output stage, added a film bypass to the two electrolytic(!) 100u coupling caps, replaced and bypassed the two PSU main caps and liberally beefed up and/or added some local bypass to caps for the power lines.

As of today it plays way better than I thought. The attached schematic (for a single channel) shows the output circuit from the dac to the audio output. The I/V and LPF are made with two halves of a humble NEC uPC4570c op-amp, std low quality resistors and with el-cheapo ceramic caps(!). Due to my limited understanding I struggle to understand the quantitative effect of the 1000p between the + leg of the LPF opamp and ground (is it making a lpf with R332/334/336)? If yes, why the following LPF seems (to me) filtering with a corner frequency of 72KHz (R336//C314 i.e. 200pF// 11KOhm)?

Better to throw it off and try a Zen I/V? But it seems I cannot find the Jfets on mouser...

Any hint is welcome,
thanks for your patience,

Stefano

Here are some photos from the almighty munich high end show 2023. This post meant to be a source of inspiration for the Diy speaker building community, so I hope you would find something for your taste. If you did, please share your thoughts! If you've been there and have more photos please feel free to expand this post 😀

Hello all

As part of a deal I received these. Apparently dipole compression drivers made by b&c
I can't seem to find what they are.
The closest thing I have seen is maybe they used them in some spatial audio Coaxial configurations?

Any help would be really appreciated
Thank you

For the last two months I've been conversing with a leading DIYaudio member here in order to finish designing and building my speakers. Today my account shows no conversation tab at all! Don't tell me that all that invaluable text was deleted??!! I've been a member since 2011.

If you buy parts on Mouser: consider shelling out for real UPS or Fedex instead of "UPS mail innovations."

I placed an order almost a month ago, picked this low cost shipping option, and now regret it. The tracking hasn't updated since March 8th. Today is April 1st.

A search for "UPS mail innovations" suggests this has happened to other folks.

This isn't Mouser's fault, it's buyer beware I guess. Though it'd be nice if they'd offer more first class mail or priority mail options. This might tip things in favor of digikey which I think still has a first-class mail option.

Guess it's just another "surprise chain issue" / something that couldn't possibly be that bad, oh wait, yeah it is.

If, say, I wanted to build a 300W-ish @ 4 ohms AB power amp for bass guitar applications, are there any proven designs I could look at? My requirements are:

• headroom and good (graceful, gradual) clipping behaviour
• reliability and ability to sustain long periods at full power
• passively cooled

My idea was to replicate the Gallien Krueger 800RB power amp, which satisfies these criteria, but I'm OK with looking for alternatives.

Maybe it is the same model as mentioned under
https://www.diyaudio.com/community/...eview-in-english-and-schematic-wanted.255097/
but one of the first devices from 1989 :
http://www.hoererlebnis-verlag.de/he/archiv/38omtec.htm
Exactly I know this after check the circuits of gain/RIAA stages.

Unfortunately an annoying problem due sprayed of construction mounting PU foam
(polyurethane foam) into the enclosure after installing the PCB.

Because of some bloated caps in the PS (first attached images), no functional check is possible without risk (danger of explosion - check out image search by google keyword "bad caps").
I also noticed that the usual bypass capacitors are simply missing on the voltage regulators and the rectifier is only a very small bridge version.

Who can upload this?
There are only to find a review in German language:
HRERLEBNIS - Die Zeitschrift fr Musik und High Fidelity
but not in other languages, particularly in English.
Thank you.

Omtec's describtion on their old website concerning their very special features (in case of the cartridge load) is follow (only in German):

Der Kurzschlußbetrieb (shorting mode resp.Voltage ShortCut - abbreviation "VSC")
wurde von omtec entwickelt und erstmals in unserer Phonovorstufe
eingesetzt. Dabei wird das TA-System nicht mehr mit einem Widerstand als
Lastimpedanz betrieben. Beim Kurzschlußbetrieb (engl. Voltage ShortCut
VSC) ist der Eingangswiderstand des CP-1i antares (nahezu) Null Ohm, was
praktisch bedeutet, daß das Tonabnehmersystem auf einen Kurzschluß
arbeitet. An der TA-Spule baut sich kaum noch eine nennenswerte
Ausgangsspannung auf. Stattdessen wird der im System durch die
Nadelbewegung generierte Strom maximal groß. Eben dieser Generator-Strom
wird dann in der Phonovorstufe verstärkt.
Ein Vorteil dieser Methode besteht im sofortigen und vollständigen
Abfluß der bewegten Elektronen. Weder in der Spule (mit ihrer
Induktivität) noch in den Kapazitäten der Verbindungskabel wird jetzt
nennenswert Energie gespeichert.
Besondere Bedeutung erlangt der sogenannte Kurzschlußbetrieb für den
Tonabnehmer noch aus einer anderen Richtung: Eigentlich alle Systeme
besitzen entweder im Hörbereich oder darüber eine Resonanz, die sich auf
den Frequenzgang auswirkt. Manche Tonabnehmer erhalten hierdurch eine
unnatürlich kantige Hochtonwiedergabe, die der Laie dann gern als
‘analytisches Klangbild’ bezeichnet. Wie auch immer. Mechanisch bedingte
Resonanzen der Tonabnehmer werden im Kurzschlußbetrieb auf elektrischem
Wege durch das System selbst gedämpft. Wir kennen den Vorgang beim
Lautsprecher, bei dem die Membranbewegung durch den Ausgangswiderstand
des Verstärkers bedämpft wird.

FS:

• 3x partialy assembled δ1 - 1 available, 06/06/23.
• 2x Assembled LCDuino - Both sold out, 05/30/23.
• 2x Motorized potentiometer (P/N: RK16812MG099, Motorized potentiometer 16mm 100K ROTARY 3B TAPER) - Both sold out , 05/30/23.
• 2x Assembled σ25 - Both sold out, 05/30/23.

The relays are G6JU-2P-Y-DC4.5 with silver and gold contact materials. Resistors are Vishay RN55 0.1% precision.

Please PM.

I have an LM1875 based kit amp I built in 2014. The company hasn't existed since 2015 or 16.
It's got a Toroid-based power supply with a 12V output. I used one channel of this amp for years in a mono setup... The other was unused.
Now I'd like to modify it for a different project to still be a mono (small sub) amp, but double power. (into 8 ohm speaker) I have a diagram that supposedly shows what I'd need to do....
Since I can't find any verification of this...is this really how bridging 2 LM1875s should work? Just add the 2 resistors at the appropriate locations on the board and change the output setup? (See pic.)



Also, can I run an accessory off of 1 side of the power supply? I'm looking at buying a subwoofer preamp/low pass board that needs single sided DC supply...is there any risk of harm or problem if I run this off of one side of the DC supply for the LM1875 boards? Or do I need to find a separate DC source for another <100ma (guessing) load?

Thanks for any help...I don't fully follow how exactly this stuff works...so just want to verify with someone who knows more than I do!

-Nate

For Sale, two ART Mic Preamps. Have 12AX7 Tube. Both work great, but no longer needed. Both come with their power supplies...

How's $80 Shipped CONUS?

I have one with no power ..I checked the power mosfets and output mosfets.they good ..I have not work on any of these before .can I get some tips of where to start ..thanks .

I am looking for an old style THT digital log-pot that has an amazing sound, but I am not able to find any advice on the subject.
There is among other the MCP4162 but is it just a log-pot or is it in fact a hi-fi log-pot.

What do I have to look for?

Although I did mail the mods to separate the info on a symmetrical B1 from the standard B1 thread this wasn't done. Info on the symmetrical B1 confused some people so I opened a new thread. Making the B1 with symmetrical ( +/-) supplies makes it possible to go capless or DC-coupled with the B1. Since 99% of standard equipment has out- or input caps this will be beneficial as long as you know what you are doing. So it is not exactly without risks. You've been warned. These are some points as quoted by Salas:


1. By trimming the supplies a bit non symmetric, the output offset falls to either zero or under half mV, steady. It counteracts naturally non perfectly alike JFET pairs.

2. If the applications situation can be non safe (general tests use with possibility of unknown non DC offset checked sources?), an input capacitor only can be used. It will be small value and can be even Teflon and rather affordable. That will obviously guard against most of the danger scenarios and will still be cheaper and more transparent than having an additional big output quality cap. The DC coupled output will not deviate to non safe, unless one psu ceases when in service, or the input resistor to ground is not used and a pot becomes dodgy. Always use that resistor, does good to the pot's transparency too. Hence, a non issue.

3. Each one to his own risks. Situation is well reviewed.

4. Benefits are: Much cheaper, audibly more neutral, more compact.

5. Risks are: If you are not careful and there is no input capacitor in your power amplifier, or DC output sensor and relay, you can burn woofers, if you connect a source device with much DC offset, or one symmetric B1 supply fails during service. Be warned.



I hope something nice will be created with the schematic Salas designed. Crt ( La Ode ) did a design on the PCB which is not 100 % finished but it is useable.

I recently purchased a quad fm4 tuner serial 24996, i can manualy tune any station but when i try to save i can do it at preset 2 and it saves it to 1 and 2 with same frequency, then if i try to save a diferent frequency in preset 1 it saves and changes the number 2 as well to same, when switched off no matter what station allways start at number 2 preset.
when i press the preset buttons from 2 to 1 it goes, but not from 1 to 2, i need to press 5 and then i can press 2, if someone had such issue or have possible slution i will apreciate
T:I:A