Hi All, due to an accident with my very durable Medo AC0110 air pump, I am now looking for a new more quiet air pump for my ET-2 tonearm.

I have found a direct replacement but I want a more quiet pump around 15psi for my ET-2. I will be using an exiting Air Pressure regulator and just a low noise pump now.

any info on where I may find one will be greatly appreciated.

What device do actual techs use to measure the frequency response of an amp? 20Hz-20khz.
Can you play a 20Hz- 20khz sweep from something like a WAV file or CD and monitor the voltage of the amp's speaker jacks and note any deviations with a multimeter? This would be assuming your source of the sweep has a "flat" output, which I suppose you could measure/monitor before running it through the amp. Would you measure with the amplitude of the source turned up to like 90%. Just thinking 100% amplitude could introduce clipping. Thanks.

I have been itching for a new project and I've been considering a lot of ideas. I keep coming across rave reviews of the SB acoustics SB15 and SB17 drivers with their various cone materials. I understand that the SB23 size motors are not quite as good. I am planning a 3-way (+sub).

I use a miniDSP 4x10 active system and also run 4 mono CSS SDX10 subwoofers which I am keeping. I like to use sealed woofers on the mains with a 2nd order electrical high pass that coincides with the natural rolloff of the woofers if possible so a 60hz to 80hz sealed box f3 is actually ideal but the subs play quite cleanly up to even 150hz if needed.

I think for this project I would really want to try the MFC cones. My thoughts were to use a pair of SB17MFC as woofers with a single SB15MFC as a midrange. What I am not so sure of is where to go for a tweeter. I would hope that the midrange would play nice up to 2.5khz. I could use a steeper crossover if necessary of course.

Since these drivers appear to punch well above their price point, I don't really feel the need to be stingy with the tweeter. But looking at the SB acoustics tweeters, I don't see anything that stands out as great at a glance until I get to the Satori line. I might also consider some kind of ribbon because I would love to give one of the better ribbons a try some day... and well...you only live once.

Here are a couple tweeters I would like to try mostly just based off of other peoples' reviews. Would like to hear your thoughts on all of this or other suggestions that you really think would be a good fit.

BlieSMa T25S-6 or T25B-6
Scan Speak D2608/913000 (Formerly Peerless HDS 810921)
Viawave SRT-7

I want to build my own Bluetooth speaker with 3 drivers; 2 full range speakers and 1 subwoofer. I plan to use a 57mm passive radiator only on the subwoofer compartment. Is this a good idea? I've made a 3D sketch as an example of the box I'll be making.

fyi, the full range speaker is 2 inch, and the subwoofer is 3 inch.

I want a project to keep me busy for a week or so but I'm getting slightly overwhelmed by all the options available so I thought I'd start a new thread to collate all my options.

• I have IEMs, planars and dynamics so ideally it can drive all of those, but being able to drive planars and dynamic cans is a must whereas IEMs are optional.
• Something more powerful than my current Atom amp would be very nice, especially as I want to power hard to run planars.
• I want something fully discrete as the Atom is opamp-based.
• Class A would be nice but not necessary.
• Since I live in Hong Kong, getting a cheap chassis from taobao isn't a problem, so there's no need to set aside too much money for that.
• I have a hot air gun and know how to do SMT soldering.
• Nothing too expensive please, I'm a student!

Hi Everyone,

I just picked up a pair of Model 2SW1's that are going to need some work. The panels look ok and I've examined them and no burns , flapping or peeling of the aluminized mylar.

The amps have been muddled. So much work is needed. Can anyone say what type of diodes are required in the voltage multiplier PIV and current?

Thanks.

Hello 🙂 I have about 60 of these tweeters, all brand new. These are identical to the ND28F-6, except for using a more compact square shaped faceplate. Someone interested in making a killer line array should drop me a line!

I would be happy to give someone a bulk discount, but I am thinking $12.50 per tweeter plus shipping and fees for those who just want a few. I think this is a pretty good deal, since these tweeters sell on Parts Express for $26.98 each.

"This compact 1-1/8" soft dome tweeter offers the best of both worlds. A low free air resonance together with a compact faceplate. Great for MTM or line array designs"

https://www.parts-express.com/pedocs/specs/275-040-dayton-audio-nd28f-6-specifications-46119.pdf

Greetings,

I'm working on a pre-amp that uses TL74 op amps. I don't have the pot that connects to J4 of the attached schematic. Any guesses on the type or value?

Assuming a standard pinout of:

gnd -> pot pin 1 (j4 pin 2)
out -> pot pin 2 (j4 pin 3)
in -> pot pin 3 (j4 pin 1)

I have tried several pots of various values without good results.

Thanks!

Won these in a raffle at the Parts Express Speaker Design Competition a few days ago. Haven't played with them at all. I was really excited when I won them, but after looking over their specs and such, I don't think I can find a good use for them. It's a shame, they seem like top notch speakers. Anyways, I was hoping to get $275 for them in a local sale, so that I can fund a project using some drivers I got at the garage sale. Might also be interested in trades for smaller pro drivers, or honestly anything audio haha. I'm in Dayton Ohio. Thanks for looking 🙂

I have a Willsenton R800i 300B 805A 48W amp and I order a complete set of tubes for it. My question is. I ordered 805 tubes not 805A. They look the same. The Cossor 805 are the tubes that i purchased and was wondering do I need to return them?

Audio Technology (by Per Skaaning) pure mid drivers (15H52 1006 SDKAM). Price is for the pair. Will ship in original box anywhere at buyer's expense. Light use and very good condition.

Asking 250USD for the pair.

Hi, I'm using this board:
https://nl.aliexpress.com/item/4000..._main.391.21ef79d2PIMP8L&gatewayAdapt=glo2nld
Powered by an ILP 7UR30, 30-0-30V 5A toroid transformer switched on via a softstart module.
The on/off switch is one with built in lighting, which switches a 12V transformer, which in turn powers a relay which switches the 230V to the soft start, as I wasn't comfortable switching the mains via the relative small on/off switch. Mayby overly complex, but it works.

The amp works very well, impressive bass and minimal heat on the chip (35°C after a night of running), the picture above shows the first test set-up using a low-pass filterboard, powering a subwoofer.

What's annoying is the 'thump' when switching the power off, even after I added a relay board, which works fine when powering up, switching on the speaker output with a delay, but it's obviously too slow to prevent the thump switch off noise.



I read in the datasheet that there is a built in standby/mute circuit in the TDA7294:

"Other features
The device is provided with both stand-by and mute functions, independently driven by two CMOS logic
compatible input pins.
The circuits dedicated to the switching on and off of the amplifier have been carefully optimized to avoid any kind
of uncontrolled audible transient at the output.
The sequence that we recommend during the ON/OFF transients is shown by Figure 18.
The application of Figure 19 shows the possibility of using only one command for both st-by and mute functions.
On both the pins, the maximum applicable range corresponds to the operating supply voltage"

I should not need a relay board.

The pins required are not connected by the manufacturer of my board, but I can solder a thin wire directly onto the pin.

But am I correct in understanding that I need to connect the supply voltage (30V!)to that in in order to activate the mute function?
That's scary...

Is there a schematic showing how to wire the mute/standby function, completely, so even a 70 year old (me) can understand it?

Regards, Jan.

Hi
I am in need of a schematic & service manual for the Cyrus 6A amplifier, mine has failed showing psu service.
Any help would be appreciated.

Regards.

I bought a pair in february 2023 on usato.audiograffiti.com, they were in really good condition, i only used one, so the other is for sale, in his original box.
So pay attention please, only 1 unit for sale
100 €
The shipping cost will depends on your country, i'm from France

Performance ranking of CLASS D power amplifier MOSFET.

LJM personal opinion. For reference only.
I will rank by performance index. Mainly thd+n. Instead of ranking by power.
Add some test data by the way. For reference.
I mainly use IR here. Infineon as a reference.
Other manufacturers will not do it for the time being.

NO1 IRF6645 0.004% THD+N 60W 4R（IRAUDAMP4S, IRAUDAMP5)
NO 2 IRF6785 0.005% THD+N 125W 8R( IRAUDAMP6)
NO 3 IRFI4019H, IRFI4020H 0.007% THD+N 60W4R ( IRAUDAMP7S) 【L15D,L15DSMD, L20D,L15DX2]
NO 4 IRFB4019PBF, IRFB4020PBF 0.009 THD+N 125W 8R (L15DPRO, L25D]
NO 5 IRFB4227 0.07 % THD+N 600W 2R( IRAUDAMP9, L30D）

Can someone characterize the sound quality of the so-called "active" MM/MC cartridges with a micro-preamp placed in the tonearm, such as Yamaha HA-2, Phaedrus Flux, ClearAudio Absolute Phono? Are they really so complex and perfect that they justify the price of 10 k$$ like the Absolute Phono? In comparison with phono preamps located in a box and connected with carts via long cables.

Got another mtx TA92001.

Botched repair by someone else. Fixed most of the issues I found (d401 had been flipped backwards; confirmed with my functioning 92001)

All output fets removed no shorts found between the open veers . Power supply side operates beautifully. High side 3120 optocouplers also removed.

Powering the amp up on the high side I'm getting 140vdc on both the gate and the source which slowly falls to 122vdc and stays there. On the drain I'm getting 112vdc

Low side of the output shows -115 on gate and source. Drain also shows 112vdc.

This can't be right? What part would fail and cause this? The only thing I can find faulty is one of the output inductors which I have pulled out of circuit to rewind but that shouldn't cause this issue right?

I've a commercial box with an 8" bass/mid and a 10" passive. The passive died of foam-rot and having tried several replacement surrounds can not get tuning correct.
So.. opted to try a reflex port..
Driver parameters..Fs = 24.2 Hz, Vas = 2.95 cu ft, Qts = 0.28, Qes = 0.32, Qms = 2.30, Mms = 29.9 gm, Re = 3.52 ohms, SPL = 87 dB, Le = 0.32 mH.
and both Qspeakers (linux) and an online calc give the following..

Butterworth B4 Ported
Vas = 2.95 ft3
fs = 24.2 Hz
Qts = 0.28
D = 17 cm
Dimensions
Vb = 1.33 ft3 = 37.66 lts
=LxWxH
f3 = 34.99 Hz
fb = 28 Hz
Dv = 2 in = 5 cm (port diameter)
Lv = 6.59 in = 16.16 cm (port length)

which match closely the commercial box volume and so I tried the port recommendations.

However, no matter whether I try a ported enclosure as shown, or a sealed enclosure, or any of the failed passive I measure only a huge peak at approx 80 Hz.
The original passive had a very compliant foam surround which perhaps no amount of weight/loading on the replacement rubber stiffer surrounds will match but I thought the reflex port recommend would make some change.
Tomorrow I may try a very large and long port and see if that can modify the peak and provide the 2 lower tuning peaks that I am told to find.

Any and all guidance appreciated 🙂

(The box and box volume are immutable due to WAF so a port tuning is desired)

I only kinda understand this, but my understanding was that Triode and Pentode tubes were different. How are some amps able to switch between these modes on the fly? A quote regarding the Rogue Audio Cronus Magnum:

"The design’s tube complement (two 12AX7, three 12AU7, and four KT120 output tubes) now allows users to switch “on the fly” between triode or “ultralinear” (pentode)"

What is it about the design's tube complement that allows this? Is there any compromise implied in having tubes that can run in both modes, if only one is desired?

Hi everyone,

Finally getting around to posting some pics of my Travelers build I started back in July. Ordered the full kit from Meniscus and just finished them up a couple of weeks ago.

Since I spend a lot of time in my wood shop and most of that time listening to music I decided to upgrade my 25 year old Sony speakers. Figured that the Travelers fit the bill perfectly.

Used 3/4" MDF all around except for the front 1/2" baffle section. Didn't have any 1/2" MDF laying around but did have some nice baltic birch ply. Worked out perfectly. I assembled the cabinet completely and cut the speaker and port holes afterwards. This allowed me to use my vacuum bag system to apply the Koa veneer. Worked out perfectly, the cabinet is plenty strong to handle the vacuum pressure. Finished the cabinets with a sanded in Liberon Oil finish prior to cutting holes as well. This is a super easy finish that looks very nice. I probably would have sprayed with lacquer if they were going in the house but I'm really happy with how they turned out. Have had a few folks give me a hard time about these being shop speakers!

As you can imagine fitting them in the shop has been a challenge due to equipment, shelving, floor space, etc. At the moment they are actually sitting about 66" off the floor and I have them angled downward. Initially I had them in an equilateral triangle position about 15' apart. Wasn't super happy with the sound stage so I moved the speakers closer to about 11' apart. I'm liking the new positioning much better. My listening position is behind my workbench 15' away. The right speaker is about 20" from the back wall while the left is about 15". I'm going to extend the shelf on the left one so they are the same.

They are being driven by an Adcom GFA535II amp, 60wpc conservatively at the moment. Thinking about pulling some heavy iron out of my living room setup to see how the bass compares with higher wattage. I did allow for bi-amping in the setup so may try that route as well. They get plenty loud as is and I'm really starting to enjoy them. Separation is just outstanding, fun to hear all of the instruments.

I was hoping to get some comments from @jholtz in regards to the option to plug the mid. I did build the plugs and you can definitely hear a decrease in volume when plugged. I understand that their is a resistor change in the Finalist design but wasn't sure if the same values apply to the Travelers. Any input would be appreciated, always looking for an excuse to play with my new toys!

Thanks for everyone who's posted Travelers and Finalists build in multiple forums. And thanks to Jim Holtz and Curt Campbell for an awesome design.
You definitely saved me a lot of time on this build.

Cheers, Keith

I want a quick-and-dirty prototype, so I am thinking about using a .23 cu. ft. Denovo CNC MDF box kit from Parts Express (6.9 Liters). There will be a 5-inch woofer on the front panel, and a 5-inch passive radiator on either side, for a total of two. Woofer and Passive Outside Diameters are 5.8 inches. Cabinet EXTERNAL DIMS 11.5 H x 7.5 W x 8.5 in. D. The front-panel woofer position will be dictated by the tweeter's OD of 110mm (4.33 in.). However, the side-mounted passive radiators can be moved around a bit within the side panels; which, seen head-on from the side view, are 11.5 in. High and 8.5 in. Wide. In terms of up and down and left to right, are there any valid engineering reasons for choosing a position other than at the center of the X made by the two diagonal lines? I am somewhat tempted to displace the center of the opening for the passive radiator from the 50/50 position, to a position of 61% up from the bottom, and 61% toward the rear of the box. Why? Because I am, at heart, a 14th-Century Irish Peasant, and Phi, the Golden Ratio Constant, is my favorite Superstition and Totem. All comments welcome; and, have a great weekend.

Hi all,

Complete newbie to speaker design so go easy on me.

I’m a woodworker and got an enquiry to build a pair of Troels Gravesen cabinets. That job looks to be going ahead which really excites me!

Having got my head back into speakers after a long hiatus I wanted to build myself a set as a starting point. Rightly or wrongly, I saw a video from DIY Perks and basically mimicked his design (after purchasing the 3D models).

Login to view embedded media
Anyway, this is the route I’ve gone down and I’m sure it’s open to ridicule, but I needed to start somewhere.

I’ll be able to get the exterior looking immaculate but want to learn how to get the most from the innards. All advice welcomed. I assume I need to buy a microphone and some software?

Mike

A discussion was had between Scottmoose and I over wood selection for building horn speakers. Different types of finishes were also discussed. Obviously like anything else in audio, preferences and bias will depend on personal preference & thy ear taste buds. It seems the subject might make a nice discussion thread.

Here is a little of my experience with diff woods and Spawn designs...... This should get the thread started...

I've built three pair of Saburo's and two Sachiko's. One pair of Nagoaka D90's and a pair of Derek Walton inspired voigt pipes from solid pine.
All of them I've built from different wood and used different finishes.
My first Saburo was constructed from 3/4" Maple Ply. The front and sides were covered with Maple veneer to hide the ply edges. I then coated them with a water based General Finishes Polycrylic, which is recommended for Maple as it stays clear and does not yellow like some oil based poly is prone to.
The second set was made from Cherry ply with no veneer. Stained and then coated with the same polycrylic. (easy to work with and clean up)
Both were in my listening room at the same time. (photo below) To this day I still feel the Maple ply had a "livlier" sound. Perhaps quicker sounding? The Cherry had a deeper, robust sound.

One Sachiko was built from Birch ply and the other from Maple ply. A close friend of mine had my original birch ply pair that were painted black. (Photo on the Frugal-Horn splash page) He requested I build another for him from Maple and veneer the front with Mahogany to better match his room. When we swapped out the drivers and fired up the new cabinets, we immediately noticed that the new Maple cabinets had that lively sound I mentioned before.
I have a pair of Maple Saburo's about 3/4ths complete. Perhaps some Mono experiments are in order with one finished and one with no finish??
Would be happy to hear your thoughts and observations regarding wood species and finishes.
Photo below is of the Maple speakers and Cherry ones in my listening room at the same time.

Before deciding to run the Jordan JX92s full range, 2-way designs were tried with both this tweeter and the HiVi RT1C-A. The Peerless/Jordan combo crossed over at ~1300 Hz measured technically excellent but was a bear to get there and sonically didn't do it for me. Following up on why, a few different simple baffle treatments were measured to see if something was just missed in implementation. Maybe so. The Peerless sends so much energy orthogonal to its axis that even its 1.5 mm front plate 'baffle step' apparently requires careful consideration.
The composite graph below shows the frequency response deviations caused by the different treatments versus a bare tweeter. The big surprise is the felt sheet, a lot of wreckage for an absorbent pad 90 degrees off axis. BBC-style felt looks pretty good. All plots were time windowed to remove the effect of the baffle edge. The only hint about the felt sheet's impact is a significantly increased spike in the Energy Time Curve.
A Jasper Jig is expected today to recess the tweeter for optimal testing. If it improves on its already +-1 dB response, given the very low distortion it may get a second go with the Jordan.
Suggestions welcome or feel free if you want to see some of the other measurements.

I recently acquired a pair of nice SE Lundahl LL2765 (60 ma version) and have been trying to find a good headphone amp schematic to use with them. They are 5K primary and 32/300/600 ohm taps. I will be using these with 300 and 600 ohm headphones. I was originally thinking of 45 tubes or maybe even 112a.

Not being an engineer with common engineering knowledge can sometimes cause issues in ones brain, so here I am and I am going to do my best to ask the question.

Lets look at a specif amplifier, the XA60.8. It is a mono amplifier so can only accept either left or right audio signal. It is also fully differential. The buffer stage takes the incoming signal and sends the (-) to the left output stage and the (+) to the right output stage (OS) (seen from above). Each of the output stages has a + and - out since its differential. They can be used for stereo and mono operation as in the same output card is found in the XA30.8 stereo amplifier as well as in the XA60.8 monoblock which we are using as an example.

Now it gets a bit more complicated: As lined out above, the buffer / gain stage, are sending only portion of the sinewave to the OS, meaning each of the output stages see only half of the sinewave, half of the polarity and so naturally, both sides are needed to operate the loudspeaker since the loudspeaker need its full sinewave.

With each of the output stages having one set of +O / -O and a + and - binding post, the XA mono platform have 4 sets of binding pots.

When I learned that the XA200.8 is a “differential” amplifier, I inquired of Pass Labs to provide explanation. Desmond explained succinctly, allowing a quick glance at the topology, “… the amp is effectively bridged inside. So, both terminals are hot (+/-), not unlike balanced cables. The advantages are distortion and noise cancelling, and more voltage swing.”

In the event that you glossed over the above section, do NOT try using both sets of outputs to power one pair of speaker posts with the XA200.8, or with any amplifier employing a dual differential design! You cannot safely sum channels with such an amp!

Click to expand...

Question: How does the internal bridging work - are the binding posts bridged as in: (Left +<bridged>+ right) and (Left -<bridged>-Right) either binding post pair can be used to operate the loudspeaker ??????

Quoted source: https://www.dagogo.com/pass-laboratories-xa200-8-pure-class-monoblock-amplifiers-review-part-1/

Sunvalley adjustable equalization phono stage SV- EQ1616D (120V version) for sale.
I built my EQ1616D phono equilizer about 9 month ago. It worked great after first time powered on. My big impression about this phono equilizer is it definitely provides tremendous details. I hooked it up with Sansui SR-838 (Denon MC), McIntosh MX110Z and Sunvally SV-S1616D SET tube amplifier. The speakers are Rogers Studio 1A. It has low usage but it is broken in now.

Asking $1100; free shipping to the continental US (sorry no international shipping). This phono stage has fabulous reviews! Look them up!

Tubes included:
ECC83 / 12AX7 　x 2
12AU7 x 1
Cossor WE274B x 1


Stereophile Review - November 2020 edition
Gramophone Dreams #42: Sunvalley Audio SV-EQ1616D phono equalizer | Stereophile.com


I made below upgrades.

--replaced stock tube sockets with Belton sockets
--Mogami W2314 microphone shielded cable which has very low microphonics
--replaced C1 film caps in input sector with Mundorf EVO oil
--replaced C3, C5 and C6 film caps with Mundorf EVO gold silver oil (bought 5mm male to female stainless hex spacers to increase the clearance below turnover select board in order to accommodate slightly larger Mundorf caps). It is also a good idea to put on heat shrink tubes on the two 30mm spacers supporting the turnover board.
--Takman resistors in signal paths (the stock resistors are already high quality ones, The reason I liked Takman is its wire terminal is stiffer than most other brands. It is easier for arrangement for point-to-point connection.)

Spec:
● Phono equalizer that emphasizes sound quality
● 2 input systems that are ideal for using 2 turntables
● Output: 1 system (MONO (L) / STEREO switchable) * MONO: L channel Input → L / R dual output
● Compatible with MM / MC cartridges (MC input: head amplifier) * MM: 47kΩ, MC: 20Ω to 50Ω
● Gain: MM35dB, MC + 22dB
* Gain can be selected according to the output voltage of the cartridge ( When HIGH / LOW) or LOW is selected -4dB (MM) /-2.5dB (MC)
● Vacuum tube: Amplification stage (V1 / V2): 12AX7, 2nd stage (V3): 12AX7, 12AU7, 12AT7 can be selected arbitrarily (according to your taste)
* The standard is all 12AX7, and if you want the smooth texture of high frequencies with a high output cartridge, 12AU7 is recommended only for V3 ( I have RCA clear TOP or Brimar to pick)
● Rectifier: Standard / diode module, option / various rectifier tubes (5AR4, 274B, 5R4 etc. can be used) ( I have LinLai 274B, WE274B, ACME 274B or ELROG 274B)
● Turnover frequency adjustment: Switchable
  → Compatible with RIAA, old AES, COLUMBIA / old NAB, LONDON, EU SP , US SP
  * Not only turnover frequency but also low frequency characteristics can be changed simultaneously according to each EQ curve.
● High-frequency roll-off adjustment: ON / OFF selection type
* When ON: Continuously variable (corresponding to all EQ curves), When OFF: No attenuation (for SP LP)

Reading this recent article and Bose patent (not patented actually), I would like to ask if these resistors can be applied to FR cabinets to dampen resonances:

https://audioxpress.com/article/pat...ive-elements-for-ported-transducer-enclosure/

Thanks,
Roberto

Calvin suggested I look at JMJ L12v2 to build an amp to drive a pair of modern ESL's (2905).

Looking at his web-page on the board he suggests:
"Due to the four power transistors it is possible to connect two amps in a bridged mono configuration"

Would this simply be matter of bridging two boards with wire or would other
components have to be added ?

As it is current that would that is required to drive electrostatics am wondering if it is possible to parallel the output of two of these boards?

My intention is to set amp up in dual mono configuration L&R having a dedicated torrid and power supply.

I am converting the Sony TDM-IP1 Digital Media Port iPod Dock to RCA. This post was a good start to find and understand the pinout.
https://www.diyaudio.com/community/threads/sony-dmp-to-line-in.183135/

I connected:

• AGND(L) and LGND(R) together and to the RCA GND
• L to Left channel
• R to R channel
• VBUS to 5V source
• PGND to the GND source

In the above configuration iPod starts to charge, great news. But no music. I have to disconnect the power (5V) so the music starts to play.
So I have one or another. Not sure what I am doing wrong.
Any ideas?

Good day. I need if someone has information about the original crossovers of some AKAI SW177 speakers, as you will see in the photo, the capacitors are exploded, honestly, I don't know what they connected these speakers to. I was looking for some information on the internet, but I didn't find anything. Thank you very much

(I can't figure out in which forum to ask questions of a more "audio-theretic" nature)

Suppose you came across a truly awesome speaker but only ONE. How can existing 2-channel music best be played, using the ONE plus support speakers, ASP/DSP/etc.? Any simple circuits to extrapolate L/C/R 3-channel out of 2-channel?

"How to convert 2-channel audio to 5.1 surround sound" seems to be a Frequently Asked "hook-up" Question (one can then use the ONE as Center), but I'm interested in both the theory of it, and actually listening to high-fidelity 3D sound without first remixing manually.

Surely everyone has had this "necessity" at some point.

One Pair. Used about 300 hours.
Excellent transformers for gm-70
Selling because I replaced them with a custom made nano - x
Asking 600 euro ex shipping

Hello All,

I am trying to calculate the resulting sound pressure levels (SPL) from two different voltages applied to a speaker (not at the same time). The speaker is 4 ohms with a sensitivity of 86 dB, for 2.83V.

For example: If the voltage difference was 0.5 Vrms, the calculation would be 0.5 x (86 / 2.83) = 15.2 dB SPL. Which I interpret to mean that the higher voltage produces a sound about twice as loud as the lower voltage.

Correct?

Cheers,
ceulrich

Hi Guys,

Does someone has the schematics from the MTX 1501D?
Attached is a photo of the PCB.

I just received this amp from a neighbor asking me to have a look at it, reportedly it is crackling on the left channel with no sound except that.

I rarely do repairs having had bad experiences but since I know him well I agreed.

I opened the amp up and immediately got a whiff of burned parts and sure enough two of the small resistors on the left channel pcb were fried beyond belief.

I do have the other channel that works and found the same two resistors, red brown brown code but cannot find this value on the schematic which I down loaded.

It is hand written copy but I do not see this value on the diagram. I do not have a lot of diagnostic tools but is there a way to check the ouputs in place. It must have been a heavy short of some kind to fry those parts like it did.

Anyone have a similar issue like this, it appears that the left board has been repaired before as one big cap has been changed and there are burn marks on the board in other spots.

The biggest issue that the resistors burned the board itself and took out eyelets for soldering making the repair that much worse.

I feel I have opened a Pandora"s box on this one, any help or advice would be appreciated, this why I do not do amp repairs, I only build a few as a hobby.

Cheers Wayne

PS I will try and take some pics and include them sometime today..

Last time I was in the attic, i saw my two, quite old electro voice pa speakers, and I got curious about the woofers. I was hoping for ev 12l, evm 12l or something similar for a twin reverb style cabinet.

I´ve been trying to decode, whats written on the back, and looking at diffrent sites. Some say it is indeed a evm 12l, but I cant´t find certainty. Maybe someone here knows more than me....😉

Is this what I am hoping for?

Hi All,

In the last few months build three attenuators.

First i built a 1/10th power 1/2 volume attenuator from Rob Robinette’s site 1/10 power switch.
(For 16ohm speaker 32r and 24r were used)



Here is the first attenuator i built




This drops a significant amount of volume but not enough for a 3-4 watt amp running on full tilt.

So I build a second one to place in series and get 1/100 power or 1/4 volume.



The resistors were 33r / 5watts and ( 49 || 49 ) for 24.5r / 10watts.
While the box is very small, it should be ok for a couple of watts overdriven and is safe to use positioned second in line ( closes to the speaker) for the amps I’m using.

This combination was used for a while, though i began to wonder if i too there was a need for a bright switch of some kind.

The third i have built after reading the following threads.
Attenuator for a 15W to 25W guitar amp and Cabinet design for 5" driver - guitar use

So i built a FAHEY Simple Attenuator, however with 16r as R1, 940r as R2 and 39r as R3 of the T pad, with true-bypass switching.
This results in conversation level volumes with a 10” speaker and 3-4 watt amp at full tilt and exceedingly quiet volumes for clean tones.





I use this attenuator on its own , and am impressed with the tone as well as the volume reduction.
It is brighter in the top end, than either of the other two attenuators individually or in series.

So with this in mind i played around with first adding a 18r on a lead plugged into the first 1/10th power attenuator.
This I understand would effectively make the circuit a T- Pad

Without the 18r in series it was less attenuated and more ‘full range’ / flatter sounding, not bright but consistent and clear.
With the 18r in series the tone was more attenuated and slightly high-mid range focused and ultimately more like the unattenuated amp but quieter.

This seems consistent with the posts in the linked topics above.

So i decided to hardwire 18r and have a switch to bypass it to give a choice of attenuation level and tonality.
The difference would not be dramatic but each flavour had its own character, one more suited to super clean and the other to different degrees of breakup and overdrive.



However and this is the surprising part for me, when ‘bypassing’ the 18r, attenuation level is less but the tonality is the same as with the 18r ‘unbypassed’.
I tested the second 1/10th attenuator which i had not modified to make sure I wasn’t imagining anything, and sure enough the ‘standard’ 1/10 power attenuator had the full-range/flat like tonality.

Now I'm wondering, how, why or if the 18r when bypassed in the sense of ‘path of least resistance’, still plays ‘active’ part in the circuit?
This is not necessarily a bad thing, and may even allow for more tonal choices, with different values of r3, either in bypass or in ‘true bypass’.
(It is likely though that there will only be so many ‘useful differences’ and perhaps one or perhaps two switchable levels or tones combinations.)

So before I rewire this first attenuator again, this time to true-bypass the 18r to see what happens please let me know your thoughts and reasons for what i’m hearing.
While i recognise this may be subjective, please enlighten me to how what im hearing may occur in the circuit.



Cheers
CrazyNutter

For sale I have 3 Faital Pro 8PR200 drivers and an LTH102 horn.

£150 for all 3 drivers, not including postage.
£25 for the horn not including postage.

Thanks, Liam

When using the Nelson's PSU Filter Relay Essentials 2022, will this filter work both the N & P channel? If it doesn't then a previous filter can be used for the P channel?

​

The "GRAB BAG" has the following:

1 NEW Sorbothane Damping Sheet 1/4" Thick X ~5" X ~4" Duro70 Strength

6 Bolt - Nut with Sorbothane Washer / Sorbothane Bushing for ISOLATING cabinets / stands / staggered speaker cabinets (i.e. mid enclosures on top of bass cabinets etc.)

8 New Rubber feet (3/4" High X 1-1/4" diameter) with integral washer
8 Used Rubber feet (3/4" High X 1-1/4" diameter) with integral washer

LOT of "scrap" 1/4" White F13 FELT - the BEST sound absorbing FELT available (expensive)

1 NEW True 75ohm BNC (6ft) ideal for DAC to transport connection (Low Jitter)

1 NEW USB 3.0 10ft cable
1 Used 15ft USB "extender" cable

1 NEW Laser Assembly for California Audio Labs ICON II / CL-10 / CL-15 CD Players

2 Jantzen Standard Metalized Polypropylene 4.7uF 400VDC
2 Jantzen Standard Metalized Polypropylene 6.8uF 400VDC

2 NEW Female XLR RFI-EMI Noise Reducer "Cap"
10 NEW Female RCA RFI-EMI Noise Reducer "Cap"

5 Used 6' foot long FT4 16AWG Plenum / In-wall OFC Stereo Cable (Some with Nakamichi Banana Plugs)

2 Wooden Gold Binding Post Assemblies with Rings or soldered stereo FT4 speaker cables ( 5 cables each 3' to 5' long)

LOT of 16 Gauge 16 Gauge twisted stereo Pair SOLID Core speaker or connect cables

100 NEW Neutrik " NLFASTON Crimp connectors 14-16 wire

1 Origin Acoustics "Preamp" (requires 24VDC Power Supply)

12 Miscellaneous circuit boards from Sonance 2120 Cinema / Sonamp 260 power amps

100+ NEW Miscellaneous 1/2 Watt Metal Film / 1 Watt Metal Oxide Power

8 New / Used 6 Ohm 50W Heat-Sink Resistors with Flying Leads

20 Misc Transistors TO91 500mW / TO-202 1.5A etc.
20 Misc. Diodes - 1 Amp Power & 1N4148
12 Misc Resistors - 1/4W & 1 Watt
7 - 6 Amp Type DO-41 Power Diodes
5 - 0.1uF 160VDC Film Capacitors
5 - 18VDC Zener Diodes
"Bunch" of Static-Free Electronic Component Bags
A few small polarized capacitors
3 DPDT High Power Relays - 1 New; 2 USED

The following PS Capacitors are all fully functional:
10 Used 10,000uF 63V 85°C (4 Euro-Cap from Sugden AU41) + (6 from Sonamp 2120T = 2 ELNA + 4 UCC)
12 Used 15,000uF 63V 85°C (12 Lelon from Sonamp 260 MK II)
2 Used 6,800 uF 50V 85°C (2 from Rotel 931B Integrated)
4 Used 10,000uF 63V Radial Electrolytic Caps
They are all 35mm in diameter (except the 6,800uF which are 25mm) and are 40 - 50mm in height

SOLD to Ed*

Ok, I see it if I download the PDF just not in the image in the post. The dimensions are very close to what I ended up at for the foam core homage.

http://www.diyaudio.com/forums/atta...ore-mini-build-fh3-inspired-foamcore-plan.jpg

Hi All!
Has anyone tried the R-Reg High Voltage regulator?

Since it is a series regulator, it might suitable for my phono project that has series regulator in place.
I am really appreciate any inputs about this reg
Thanks 🙏

Hi for sale the following:
MIRAND AUDIO DAC+DISCRETE OUTPUT stage+SOFT START+LPSU: 250 eur SOLD
MIRAND AUDIO GRAVITON PHONO+DISCRETE OUTPUT stage+LPSU: 450 eur

Board alone are 1000 eur.
Invoice available.

I would like to build a 3 way using SB drivers.
For WAF 10 inches wide with flat baffle so I can fit a grille.
Drivers SB23NRX 8 inch bass, 5 inch mid and 1 inch hf.
Has anyone built something similar who would kindly share the design and crossover details.

Hi,

Does anyone know how some companies accomplish a power selection switch? I'm referring to ones found on amps like the PRS MT15 and the Peavey 6505 mini head. The Peavey even has 3 power settings. I did some web searches but couldn't find much. Not sure what is typically done for this.

Things I thought of is maybe a pentode/triode mode switch or integrating an attenuator of some kind.

Thanks

Are they really necessary? This is something I’ve never seen discussed. If so, what’s the best material & method to use? I got them with my Fostex FF85K drivers years ago.

Hi All, I have no idea of how and what to do to modify my Grant Fidelity TubeDAc-11 with a ESS ES9016K2M SABRE32 Ultra DAC chip. I have the SoundBlasterX AE-5 sound card installed on my desktop but after connecting directly to the AUX connection on my Sansui AU-9500, which I'm using as a pre-amp, the sound sound is good for about 2-3 minutes. After this time, the sound become garbled, more like a tape recorder playing a tightly wound tape. Music is slowed down then garbled.

So that's really the reason to modify the Grant to accommodate the better DAC chip and rectify the sound quality problem. Is this something that is doable and how much expertise does one need to have?

I've always used a denon AVR for a 5.1 system, currently the sub is Bluetooth connected. Klipsch speakers which work well for movies. the denon takes its input from the ARC hdmi input.

now I'm remodeling the room and it looks like i have to give it up and get a soundbar. I can live with a 3.1 setup.

So id have to get rid of the denon avr, and the l/c/R klipsch speakers (they are 3 separate units). if possible, I'd like to keep the wireless klipsch sub.

so my questions and confusions are many. do soundbars process the digital formats (Dolby dd+, atmos, whatever), send the l/c/R info to the soundbars speakers, and leave a line level output for the sub and/or surrounds? I can hook my existing subwoofer Bluetooth transmitter for the sub if they do.

need some enlightenment. thx

found a cool homebrew high voltage supply, looks like from the 40's. very crude, completely unregulated, but i'm just looking for something to give me B+ for prototyping tube preamps for guitar, so it suits my needs, and i really enjoy working with such an old basic circuit. i'm looking to restore it, and am hoping for a little guidance and help in evaluating and improving the circuit. i don't want to complicate it much and i'm not interested in any regulation, i just want to make adjustments for better component longevity and reliability, avoiding oscillation etc.

the colourful schematic is how it's hooked up currently. i've also attached the schematic of a similar power supply taken from a 1963 magazine, that i found on another thread on this site (https://www.diyaudio.com/community/threads/simple-variable-tube-power-supply.96995/), for reference and improvement ideas.

at bare minimum i plan on installing a 3 prong cord, replacing the can cap with some axials, and replacing the potentiometer as it measures 180K but should be 50K. all resistors are fat ohmite wirewounds that measure perfectly on spec. tubes are a pair of 6L6 as the pass tubes, a super handsome 5Z3 rectifier, an 0D3 and a 0C3. gonna test em and replace if needed, making sure i have reasonably matched 6L6.

in terms of operation principles, i don't know much about bench power suppy design and would like to have a good ground-up understanding. it seems the large 50K pot acting as the cathode resistor for the 6L6's, combined with the fact that the plates are tied directly to the B+, allows the cathode to approach the B+ voltage? i don't understand how there can be much if any conduction across the tube if the cathode and plate are at the same potential. it seems the pass tubes are meant to operate at low current consumption until an external load is connected?

worst conditions for the pot are dropping 400V across 50K, allowing 8mA through, dissipating 3.2W. i'd like to replace it with a 10W for a nice safety margin, but unfortunately mouser and digikey only have 2W versions. they do, however, have 25K 5W's, so i'm considering one of those in series with a 5W 22K or 27K resistor on the ground side, settling for a smaller voltage range of perhaps 250V-400V, which would still suit my purposes just fine.

but i'm wondering if the biasing setup from the 1963 magazine would be preferable in any way, where the cathode uses the same proportionate resistance to ground (100K since it's only for one 6L6), and the grid voltage is instead tapped directly from the B+. does one configuration to source the grid voltage offer an advantage over the other? the only advantage i can see is that a 100K pot will only dissipate 1.6W when dropping 400V, but the same suppliers only offer up to 2W pots at that resistance, so i'd still be stuck at the same impasse. unless this value is non-critical, in which case i could use a 250K 2W.

the filament center tap was left floating, which i'm assuming is so that the filament is free to follow the cathode to keep from exceeding the 6L6's Vhk max rating of 180V. but, wouldn't this leave the 6.3V filament output terminals floating at up to 400V DC?! of course, tying the center tap to the 6L6 cathodes like in the other schematic would do the same thing, but that's why they have a separate 6.3V transformer for those terminals... thinking i'll tie the center tap to the 6L6 cathodes so it has a reference, and just not use the 6.3V output terminals. any issue having the indicator bulb floating at up to 400V though?

adding C2 from the 1963 schematic onto the output seems like it can't hurt even with my current setup, same with adding 100R screen stoppers. the 10K grid stopper seems like a great idea too, but not sure if it would affect bias if i stick with the current biasing method?

I've been using USB Flash Drives as well as a NAS for music on my streamers using the App or front panel display for navigation of the folders for Artist/Album etc.

I've just bought a little Yamaha CRX-B370D for casual listening and using USB is a bit long winded for navigation and takes some time to find the artist I want as it's not in Alphabetical order as the folders are structured. I know that it sorts files by date of file creation and I also know I can go through and add numbers at the start of the song file names so they then appear in order but not by Artist etc unless I use a number system that separates Artists and of course would take heaps of time. To overcome the time to navigate through the USB, I now only put a few Albums on the USB and when sick of them I delete and add new Albums.

The question is, has anyone found a work around to the way the player handles USB folders as the folder structure I use is Artist / Album /Song?

I want to know,is that crossover distortion?
(This is 8 Ohm speaker.)

I think it's the longest equipment review I have written in my 35 years plus of writing about audio.

https://trackingangle.com/equipment/sb-acoustics-x-solen-sasandu-tx-loudspeaker

ciao,

john

Hi

I have a TC Electronics G-Major guitar effects processor with a failed power supply. It seems this is a common issue and was wondering if any diyAudio members have had any similar experiences and resolved them with a diy fix.

The manufacturers refer to local suppliers who have a 300%mark up on a replacement psu and I am wondering if it is worth the time and effort trouble shooting the psu and fixing if it is repairable.

Any advice or direction is appreciated.

Thanks

Hey guy I'm looking for the schematic of Soundcraft Ui24r mixer or anything similar. I know soundcraft service manuals and schematics are hard to come by especially on the later models.

I've done some googling but can't find a definitive answer.

Can the latest versions of piCorePlayer support the DAC built into the MiniDSP 2x4 HD if connected via USB from the Raspberry Pi to the MiniDSP box? Right now I'm using a HifiBerry card but for reasons I won't bore you with, I'd like to try the MiniDSP provided it will work and I won't give anything up (for example, I like the ability to control the volume from the player's interface as my amplifier doesn't have a remote control).

Being working on this project for the last two years. Here the final result, working perfectly.

This project started when one of my friend brought me a defective SL1 (original), he said: <nothing serious, just a little noise at the output, probably a noisy tube...>, one month later it was fixed, nothing serious, yeah right... When I started to work on the unit at first I was completly lost, it was a very complex preamp, with a lot of SS parts near the tubes, very complex HV regulator section, and external power supply. I rapidly realized that the supply was defective, and that probably some other parts, these small TO92 SS parts were gone as well. I had no schematics, they were impossible to get, I was left in the dark.

I said to my friend I can try to fix it, but it will be expensive, and will take me a long time (doing repair part time, was still working at the time). First I needed to repair the HV section, all the heaters supplies seems ok. I started to trace the HF regs section schematic, it was a mess, even worst, some part of it was inside the external supply. I worked, and worked, and finally got something that make sense. I isolated this section, and found all the defective parts, replaced them, and got a working HV regs. Then using an external lab power supply (current limited), and by isolating each tubes section, found the shorted/open SS parts driving the tubes (then are small MOSFET), and replaced all the defective ones, tracing the schematic while I go.

While doing the schematics, it was difficult to trace the PCB, and to see where all the traces were going, so to help me I started making a PCB, to help tracing, and figuring the schematics. When I was done I had a pretty close PCB, probably with some errors, but enough to complete my schematics and the repair.

We listend to the repaired unit and we found it was one of the best preamp we ever listened to, period. And the phono section is just gourgeous. A real reference preamp...

A few years later an other friend ask me for a recommadation for his system (he has a Pass XA30.8 as amp). He was looking for a good preamp, and a phono preamp. I told him that the CAT SL1 was doing all that, in one package. I bought a used unit from Alberta, but guess what it was intermittent. I had to repaired this one two. It has a few problem, intermittent tube sockets, and a few cold junction soldering. Repalced all the sockets, and redo the solder joint and it was ok. This unit was slightly newer than the the first one I repaired, version MKII. I used my previous info for the repair, fine tuned my schematics and PCB layout, and did the few new changes.

Then finally I had to repair a third one, this one had a severe problem. The power supply main transformer has the HV secondary burned, litterally detroyed, and the rest of the HV section gone naturally. One very bad short coming of this preamp supply is this, the main fuse will let go if one of the high current heater supply short, but won't blow if it is only the much smaller current HV section. The HV really needs its separate low rating fuse.

I was pretty close the first time, and I was confident I had the real thing. During COVID I had spare time and decided to make myself a CAT SL1, my own version. To improve on the thing I don't like about the originals I worked on I decided to make these changes:

-Better made external power supply, with larger enclosure, proper layout, bigger regulator heatsinks, CRC filtering and better caps on the HV section, Separate fuses on all the outputs (Heaters and HV), and since I want SE/BAL converters in the preamp, extra +/-24V supply for these converters.
-I hate the original cable between the supply and preamp. It can't be disconnected, it is large gauge, not very good quality ( at least on the ones I saw), make working on the preamp difficult, etc... So I want a flexible cable, with detachable connector at the preamp. I know, it may not sound as good as the fixed one, but no way I'll have a captive cable on my preamp...
-Added a ground breaker to the supply, my own version of the Ayre noise filter and Furutech IEC AC inlet connector.
-The original used the excellent, and now gone REL-Caps everywhere (the new one have custom made caps). I cannot get REL-Caps, so used more mondain IC film caps for the supply, and Mundorf caps for coupling. For the output I went over the board with Mundorf Supreme Silver/Gold/Oil caps, bypassed with Duelund copper foil.
-The original has the excellent ROE resista resistors. One of my friend was able to give my most of the values I needed. Used a mix of Tantalum and Shinkoh and Kiwame resistors for the rest.
-The original used for volume an Electroswitch 24 steps attenuator with ROE descrete resistors. Again impossible to get, found a 4 decks one on ebay. Mounted all the ROE resistors, ans it tested fine.
-The Balance used a smart way of doing the balance without impacting on the channel crosstalk. It adds resistors on the lowering channel, in fact increasing these channel volume total value, decreasing the actual volume, while the other channel don't move, clever. Again it is using an Electroswitch rotary switch, got this one at Mouser...
-I made a few years back small SE/BAL and BAL/SE converter PCB, using the mostly transparent DRV134 and INA2134 chips. I installed them inside the preamp. The SE/BAL input converter is only on the CH1 input, with a switch to select between RCA and XLR. The SE/BAL output converter is at the output. Since this preamp can produce HUGE output level, I installed +/-12V protection zener at the input, in fact limiting the preamp to +/-12Vpk-pk output. If the preamp is so good I may install Lundhall balanced output down the road...
-The MK2 version I saw use Cardas hook-up wiring, I used the same.

So, here my preamp, after all this work I'm very happy with the result, no noise, phono section has a perfect RIAA curve after some tuning, same gain on both channels with the tubes I used, very stable HV supply with no noise. Yes I used a clone enclosure from China but I remade completly the rear panel, and trashed the included cheap toggle switches, bought good quality C&K ones.

Here a few measurements:
Preamp Section gain: 25.5dB, BW 836Khz, Vout max 50Vac (limited now by the SE/BAL converter inout zener at +-12Vpk-pk), THD: 0.01%, noise <1.2mvac, Zout around 500 ohms.
Phono section gain: 45dB with external load connector. Huge overload threshold. My friend use it with a Denon DL103 without problem...

I'm wondering if anyone knows of a good source for these hard to find sockets. I've seen a few NOS on an auction site, but wondering if they can be found elsewhere for a more reasonable price. Decent new production including chinese would be okay as well. Or perhaps someone here has surplus they'd be willing to part with.

Best wishes

The custom furniture designer and builder I have been using for the past few years for my loudspeaker cabinets usually does large projects such as beds, dining-room tables, and other such furniture; please see examples at the link.

https://www.custommade.com/by/corwin-butterworth-custom-furniture/

He does very elegant work--he studied at the famous Rhode Island School of Design.

Corwin is looking for some smaller fill-in jobs, so I thought I would pass along his contact information (Corwin Butterworth: corwinb74@icloud.com), and show a couple of the cabinets he made for me.

Admittedly, each of these designs has its over-the-top aspects.

The front panel of the 2-way with the gold-plated tweeter (circa 7 Liters) is Richlite Bamboo Statum composite 1-inch thick ($72 per square foot plus shipping); the perimeter edge had seven coats of traditional hand-rubbed violin varnish applied by an award-winning violin maker. The coloring agent for the violin varnish was powdered gemstone amber in poppyseed oil; circa $95 the teaspoon. So, that's an over $1,000 pair of small cabinets.

The other cabinet (circa 10 Liters) has an mdf shell, but the corner-edge protectors are of Extreme Tiger Flame Maple intended for high-end guitar and uke work (don't ask how much that costs per board foot), and the front panel is a Baltic Birch/Richlite clad composite. Probably circa $700/pr.

Corwin is very easy to work with. Shipping is of course an issue, and careful packing is a cost to keep in mind. So, probably the ideal customer is in the upper right quadrant of the Lower 48 US states, who is building a smaller 2-way or 3-way. Probably not somebody in Arizona who need a massive Transmission Line build.

Highly recommended.

john

Hello . I bought a Chinese board that resembles the original Amanero. I would like to put better oscillators for the sound. Can you help me with advice? What exactly would fit in the place of what is there? I have attached links to pictures of the plate below.

https://ibb.co/9TQ1wHM
https://ibb.co/zNMdBQ3
https://ibb.co/0DNL6wr
https://ibb.co/X44xRt2

Login to view embedded media
/örjan

Hey everyone,

I'm hoping to build a pair of these speakers but I'm having a hard time locating all the parts in the US, or from places that will ship to the US. Does anyone have an alternative to the LaVoce FBASS08-18 that might be easier to find?

I'm also not set in this specific build, so if anyone might have a suggestion for a similar build with easier to source parts, that would be great as well.

Thanks!

New screen cans noval pcb.
All 8 for 12 $ + shipping.
or 2 $ a each + shipping.

Here is my quick chat with GPT to see if it can help design boxes based on its LLM training...What do you think? It Likes to make stuff up so hard to know how accurate the rest of the information is.

@planet10 @Scottmoose @chrisb


Can you output the optimum box dimensions for a specific speaker driver if I give you the specs?


As an AI language model, I can certainly help you with the calculations required to determine the optimum box dimensions for a specific speaker driver, provided that you give me the necessary specifications. However, please note that the final determination of the optimum box dimensions may depend on various factors such as the desired frequency response, the intended use of the speaker, and other design considerations.
To begin with, please provide me with the following specifications of your speaker driver:

1. The driver's Thiele-Small parameters, which typically include:

• Resonant frequency (Fs)
• Total Q factor (Qts)
• Electrical Q factor (Qes)
• Mechanical Q factor (Qms)
• Equivalent air volume of compliance (Vas)
• DC resistance (Re)
• Voice coil inductance (Le)

1. The driver's rated power handling capacity and nominal impedance.

With these specifications, I can use mathematical models and formulas to calculate the optimal enclosure volume, port size, and tuning frequency that will result in the best performance from your specific speaker driver.



Here you go. Parameters FS 97.4826 Hz VAS 1.1523 Ltr RE 6.8 Ohm QMS 3.7689 QES 0.7752 QTS 0.6429 Bxl 3,1071 Txm SPL 83.41 SD 0.0023 m² CMS 1.5733 mm/N MMS 1.6942g RMS 0.2753 WM RAT 307716 WA RMT 1.6140 WM MMD 1.6322g h0 0.13% L1kHz 1.0575 mH PWR 7 Watts (Nom) X MAX (Mech) +/- 3.5mm (One way)


Thank you for providing me with the Thiele-Small parameters of your speaker driver. Based on the specifications you have provided, I can help you calculate the optimal enclosure volume and port dimensions for your speaker.
Using the Thiele-Small parameters you provided, we can calculate the following parameters required for enclosure design:

• Free-air resonant frequency (f0): 97.4826 Hz
• Equivalent volume of air compliance (Vas): 1.1523 Ltr
• Total Q factor (Qts): 0.6429
• Effective radiating area (Sd): 0.0023 m²
• DC resistance (Re): 6.8 Ohm
• Voice coil inductance (Le): 1.0575 mH
• Mechanical resistance of the driver (Rms): 0.2753 kg/s
• Mass of the diaphragm (Mms): 1.6942 g
• BL product (Bxl): 3.1071 Txm

To determine the optimal enclosure volume and port dimensions for this speaker driver, we can use the Thiele-Small parameters to calculate the parameters for a sealed and a ported enclosure. Here are the recommended enclosure dimensions for a sealed enclosure and a ported enclosure:
Sealed enclosure:

• Optimum enclosure volume (Vb): 9.99 liters
• Optimum Qtc: 0.707
• Optimum box dimensions: 38.56 cm (Height) x 22.56 cm (Width) x 18.62 cm (Depth)

Ported enclosure:

• Optimum enclosure volume (Vb): 18.13 liters
• Optimum port length: 9.46 cm
• Optimum port diameter: 5.08 cm
• Optimum tuning frequency (Fb): 43.82 Hz
• Optimum box dimensions: 45.72 cm (Height) x 27.94 cm (Width) x 25.4 cm (Depth)

Please note that the dimensions listed here are only recommendations based on the specifications you provided, and there may be other factors to consider when designing an enclosure, such as the desired frequency response and the intended use of the speaker. It is recommended that you consult with a speaker enclosure designer or use specialized software for further optimization of the enclosure design.



What response curve would this give?

Based on the recommended enclosure dimensions for the sealed and ported enclosures that I provided earlier, we can estimate the frequency response of the speaker driver using a modeling software or simulation tool.
For the sealed enclosure, the recommended optimum enclosure volume of 9.99 liters and an optimum Qtc of 0.707 would result in a relatively flat frequency response with a -3 dB cutoff frequency of approximately 61 Hz. This would be suitable for use in a small to medium-sized room or as a near-field monitor.
For the ported enclosure, the recommended optimum enclosure volume of 18.13 liters, optimum tuning frequency of 43.82 Hz, and port dimensions would result in a response with a peak at the tuning frequency and a -3 dB cutoff frequency of approximately 46 Hz. This type of response is suitable for use as a bass reflex system, which would provide a deeper bass extension and higher efficiency compared to a sealed enclosure design.
It is important to note that these frequency response estimates are based on ideal conditions and may vary depending on the actual construction of the enclosure, the placement of the speaker, and the acoustic properties of the room. Therefore, it is recommended that you measure and adjust the response using a measurement system like a calibrated microphone, a measurement software, and an equalizer to achieve the desired response.



What Mark Audio full range driver would deliver optimum QTC of 0.707 in a sealed cabinet?


To determine which Mark Audio full-range driver would deliver an optimum Qtc of 0.707 in a sealed cabinet, we would need to consider the Thiele-Small parameters of the driver, as well as the volume of the enclosure and the desired Qtc.
A Qtc of 0.707 is considered to be the optimum value for a sealed enclosure, as it results in a flat frequency response and a good compromise between low-frequency extension and transient response. To achieve this Qtc value, the speaker driver's parameters must be selected carefully and matched with the appropriate volume of the enclosure.
Mark Audio offers several full-range speaker drivers that may be suitable for use in a sealed enclosure with an optimum Qtc of 0.707. However, the specific driver that would be the best fit would depend on various factors such as the desired frequency response, power handling, and other design considerations.
Some of the popular Mark Audio full-range drivers that may be suitable for use in a sealed enclosure with an optimum Qtc of 0.707 include:

1. Mark Audio Alpair 7.3: This is a 4-inch full-range driver with a lightweight paper cone, a copper-clad aluminum voice coil, and a neodymium magnet system. The Alpair 7.3 has a relatively high Qts of 0.58, which would require a smaller enclosure volume to achieve a Qtc of 0.707.
2. Mark Audio Alpair 6.2: This is a 4.5-inch full-range driver with a lightweight aluminum cone, a copper-clad aluminum voice coil, and a neodymium magnet system. The Alpair 6.2 has a Qts of 0.4, which would require a larger enclosure volume to achieve a Qtc of 0.707.
3. Mark Audio CHR-70.3: This is a 3-inch full-range driver with a lightweight paper cone, a copper voice coil, and a ferrite magnet system. The CHR-70.3 has a Qts of 0.36, which would require a larger enclosure volume to achieve a Qtc of 0.707.

It is important to note that the optimum Qtc value may vary depending on the specific requirements of your application. It is recommended that you consult with a speaker enclosure designer or use specialized software for further optimization of the enclosure design.



Can you put into cell all available mark audio drivers and the sealed cabinet volume required for QTC 0.707


Certainly! Here is a list of available Mark Audio full-range drivers, along with the recommended sealed cabinet volume required for achieving a Qtc of 0.707:
It is important to note that these volumes are recommended for achieving an optimum Qtc of 0.707 and are based on ideal conditions. The actual sealed cabinet volume required may vary depending on the specific application and desired frequency response. Additionally, these recommendations assume that the cabinet is well-braced and constructed with appropriate materials and thicknesses to minimize panel resonances.



Is there an Alpair 4?




I apologize for the mistake in my previous response. There is no Alpair 4, but there is an Alpair 4M and an Alpair 4P. Here is the corrected list of Mark Audio full-range drivers along with the recommended sealed cabinet volume required for achieving a Qtc of 0.707:



Are you sure?




I apologize for any confusion. You are correct that there is no Alpair 4M or Alpair 4P. The correct models are the Alpair 4 and the Alpair 4.5. Here is the corrected list of Mark Audio full-range drivers along with the recommended sealed cabinet volume required for achieving a Qtc of 0.707:



If you wanted to wire up speakers for installing in a ceiling. How best would you wire these up in multiples from 1 to 20




The best way to wire up speakers for installing in a ceiling will depend on the specific configuration you are trying to achieve and the amplifier or receiver you are using. Here are some general guidelines for wiring up multiple speakers in a ceiling:

1. Determine the impedance of the speakers: Before wiring up the speakers, you need to know the impedance of each speaker. Most ceiling speakers are either 8-ohm or 16-ohm speakers.
2. Determine the total impedance of the speakers: The total impedance of the speakers will depend on how you wire them up. If you are wiring the speakers in series, the total impedance will be the sum of the individual speaker impedances. If you are wiring the speakers in parallel, the total impedance will be the reciprocal of the sum of the reciprocals of the individual speaker impedances. For example, if you have 8-ohm speakers and you wire them in series, the total impedance of two speakers will be 16 ohms. If you wire them in parallel, the total impedance will be 4 ohms.
3. Choose the appropriate amplifier or receiver: The amplifier or receiver you choose should be capable of driving the total impedance of the speakers. For example, if you are wiring up 8-ohm speakers in parallel and you have 10 speakers, the total impedance will be 0.8 ohms. You will need an amplifier or receiver that is capable of driving a 0.8-ohm load.
4. Determine the wiring configuration: There are several wiring configurations you can use, depending on how many speakers you have and how you want them to be connected. Some common configurations include:

• Series wiring: Connect the positive terminal of the amplifier or receiver to the positive terminal of the first speaker. Connect the negative terminal of the first speaker to the positive terminal of the second speaker, and so on. Connect the negative terminal of the last speaker to the negative terminal of the amplifier or receiver. This configuration is best for wiring up two speakers.
• Parallel wiring: Connect the positive terminal of the amplifier or receiver to the positive terminal of each speaker. Connect the negative terminal of the amplifier or receiver to the negative terminal of each speaker. This configuration is best for wiring up multiple speakers.
• Series-parallel wiring: This configuration involves wiring speakers in series and then wiring the series groups in parallel. This is a more complex configuration that is best for wiring up large numbers of speakers.

1. Test the system: Once you have wired up the speakers, test the system to make sure everything is working properly. Play some music or test tones and check the volume and sound quality of each speaker. Make any necessary adjustments to the amplifier or receiver settings to ensure optimal performance.

The Alpair CHR-90 has these specs. FS 44.3 Hz QMS 2.4647 VAS 26.1403 L QES 0.4212 dBSPL 89.36 MMS 4.9661 g RE 6.8000 Ohm BL 4.7260 QTS 0.3598 SD 0.0085 m2 RMS 0.5614 WM RES 39.7866 W MMD 4.5230 g PWR 40Watts (Nom) X max 7MM (1 Way)




Based on the specifications you provided, the Mark Audio Alpair CHR-90 is a high-efficiency full-range driver with a low resonant frequency and a low Qts, making it well-suited for use in compact sealed or vented enclosures. Here are some suggested enclosure parameters for the Alpair CHR-90:

• Sealed enclosure: For a sealed enclosure, the ideal volume is typically around 20-30 liters. A Qtc of 0.7 is generally a good target for achieving a balance between low-frequency extension and transient response. Here are some enclosure parameters that would achieve a Qtc of 0.7 with the Alpair CHR-90:
  • Volume: 25.5 liters
  • F3: 49 Hz
  • F10: 87 Hz
• Vented enclosure: For a vented enclosure, the ideal volume and tuning will depend on the specific design goals and the available space. Here are some enclosure parameters that would achieve a -3dB point of 49Hz with the Alpair CHR-90:
  • Volume: 46.5 liters
  • Tuning frequency: 35 Hz
  • Port diameter: 7.6 cm
  • Port length: 16.5 cm

It's important to note that these are just suggested enclosure parameters, and the actual performance will depend on factors such as the specific application, room acoustics, and listener preferences. It's always a good idea to simulate the enclosure design using software such as WinISD or Hornresp to optimize the design and ensure that it meets your performance goals.

MMCF10 amp HIFI LP phonograph MM amplifier RIAA Phono preamplifier PCB Board | eBay

Have anyone tried this one?

Hi,
I'm hoping someone can recommend a replacement relay for my NAD 326BEE to correct a problem with one channel cutting out, assuming that's actually my issue.

Background: I bought the amp used about a year ago. It was fairly pristine, but I still cleaned all the pots with Deoxit, checked for suspect caps, etc. It worked flawlessly for a while. Unfortunately, it developed an issue where one channel, mostly the left, would cut out on me. Fiddling with the volume knob a bit usually brought the channel back, so I assumed the pot was still dirty since it's motorized, almost completely sealed, and barely possible to get spray into. I tried cleaning it out again, and the problem disappeared, but returned about a week or so later. I'm not sure if cleaning it actually did anything, or it was just a coincidence that it stopped for an unusually long time afterwards. It's a very inconsistent issue, and impossible to replicate on demand. I finally got fed up enough to do some deeper research into it, but I can't seem to find any analogous problems specific to my exact model. I have, however, seen multiple mentions of issues with the NAD 306, which stemmed from an output relay that seemed prone to going bad, as is referenced in this thread. I figured it might be worth a shot to try swapping out the relay to see if it solves the issue permanently. Unfortunately, I can't find an exact duplicate of the current relay anywhere but an eBay retailer in China that's going to take over 6 weeks to get it to me. I've replaced relays before, but there was always an exact replacement available, so I'm hoping someone can recommend a product listing for a compatible relay at a Web site in the US with a more reasonable estimated arrival time. In case there's some issue with the attached image, the relay in question is a Massuse ME-11 with the text 012-2H4 and 8A250VAC. I believe the data sheet for the relay can be seen here. I'd really appreciate any suggestions for a replacement source, or any other suggestions on what the possible culprit might be. Thanks in advance.

Hello,

I purchased an Xduoo ta-10r tube amp about two years ago and it stopped working a year after the company warranty and they said it would be very expensive for them to fix.

They sent me an image asking if I could repair it myself, even offering to send me a replacement capacitor for it. Is it safe to attempt this repair? While I have opened electronics before repairs like this seem slightly dangerous to me. Plus, the metal chassis is closed with non-standard screws so I would need to make additional purchases to repair it.



They also said I could send it to an electronic repair shop. So, if anyone has any good recommendations on where to send it in Ontario Canada (From GTA). That would be very much appreciated.

Thanks for reading

This is a pair of the Hugh Dean and XRK Audio designed
Alpha Nirvana 39 watts Class A boards,
Mounted on 5U heatsinks
They are Newly built tested and Sound Fantastic just add your favorite Dual Power Supply of between 26v to 28v and you are in business.
Asking $375prefer local pickup
Huntersville, NC area
I would also consider selling the boards without the heatsinks for $300

Service Manual

I have unit that has an intermittent problem on Left channels that goes like:

• It plays fine on "Main in" (there is a split between pre and main (4 RCA)) - so problem must be in pre/line section. Its a good power amp 🙂
• L ch is silent using line in like AUX at power up and after a while, 1 minute..., it start to play
• It usually crackles a bit when it starts to play, then it can sound fine for several minutes (5-20)
• Then it can fade out and get silent - usually when signal level gets lower
• It can be fine, then play distorted / crackeling for a minute or so.... then come back OK
• It feels like it needs signal to work - like some bias is not there without signal?
• Same on AUX and Tuner so I assume som common part downstream

Happy for any thoughts or ideas...

//

Neither of my Audiostatic ES100 speakers will play high frequencies.I have a beautiful midrange but the sparkle is not there.
Since these are single panel I would think the problem would be in the interface.An ex Audiostatic employee thought it
could be a fuse or relay.I don't see a typical fuse but do see a small black box which could be a relay.Not sure how to test it.
Any help or thoughts would be truly appreciated.

This is for the push/pull amplifier using two Sony VFETs per channel, as described here:
https://firstwatt.com/pdf/art_diy_sony_vfet.pdf

While putting something together for BAF, I found enough spare parts for another vfet amp.

So I have the following available:

• A pair of pcbs: https://diyaudiostore.com/collections/power-amplifier/products/sony-vfet-circuit-boards
• 2x 2SK82, 2x 2SJ28 vfets (they are not matched)
• 2 pairs of Toshiba 2SK170BL/2SJ74BL jfets (4 jfets in total, ~8.7mA IDSS)
• 2x 2SK2013 and 2x 2SJ313 mosfets
• 2x ZTX450 and 2x ZTX550 cascode transistors
• 2x IRFP240PBF and 2x IRFP9240PBF power mosfets
• 10x TL431A shunt regulators
• 4x blue LEDs for the amp PCBs
• Resistors for the PCBs. The smaller ones are Vishay/Dale CMF/RN 1%. The 0.1R 3W current sensing resistors are Yageo/Vitrohm 1%
• 4x 500R (Spectrol) and 4x 5K (BI Technologies/TT Electronics) single turn trimmers
• 4x 1N4004 diodes
• 8x 220uF and 8x 47uF Panasonic FM and FC capactors.
• 4x TO220 heatsinks for the front end mosfets.

This should be everything you need to populate the two amp boards.

Please note these parts are from my personal stash and not from the essential or completion kits previously offered by DIYAudio.

You will have to source or make your own bracket (Please reference the drawing here: https://www.diyaudio.com/community/threads/sony-vfet-amplifier-part-2.276711/page-45#post-4581878 )
as well as supply your own mica/goop and mounting hardware.

This is not a beginner's project.

If interested, please PM me with an offer.

Hi everyone,

I recently bought a second hand Quad 306 and have been using it successfully with my Yamaha NS10m’s for about 4-6 weeks.
Sadly, the left output has now started distorting - quite badly, so it’s unusable - and I’m wondering what the best thing to do might be.

I’ve been hearing that it could be that the caps need replacing. Although, the seller - on eBay - said that he’d replaced them recently, but that’s not to say that he’s telling the truth or even if that’s the issue. I’ve also heard that replacing the TR8 (transistor?) could be a possible culprit.

Any suggestions?
Also, if it is the caps, is it something that someone with limited soldering experience can manage? (I’ve changed guitar pickups etc).

Thanks!
James

I have a used pair of SB Audience's BEST Midrange (NERO Line) for sale.

Retail is $271.95 CAD EACH ($543.90 CAD + Taxes per pair) at Solen.ca currently

https://www.solen.ca/en/products/nero-6mrn150d-16cm-paper-cone-pro-midrange-8ohm

It is the NERO 6MRN150D Neodymium model

Driver Features:

6" (162.7mm) Paper Cone Neodymium Pro Midrange
98dB / watt Sensitivity
150 Watts Continuous / 300 Watts Peak
Rated range 200 -10,600 (more realistically I have measured it pretty flat from 350 - 3.5kHz)
8 OHM Features Proprietary cone paper material with graphite
Flat foam surround for best midrange reproduction
High grade (Powerful - BL 13) neodymium magnet
Shorting ring in motor system for reduced distortion
CCAW voice coil for reduced moving mass
Minimum damping fiber glass voice coil former
Cast aluminium chassis

Condition-wise its an 8 overall
Paper / graphite cone / flat foam surround rated a 9
A few marks on cast frame / Mounting screw holes (See photos for reference)

Selling this PAIR for $169.95 USD with FREE Shipping in Canada & US

Hi guys
I'm missing SA501 and SA502. Are these a TVS diodes ? They were badly burnt but I could still read something like 3 stripes red green red. I highly doubt it's a 3 band resistor of 2.5KΩ. They are being used in the preamps section in between the RCA shield and the secondary ground of the transformer. I 've also found that the traces from the secondary gnd to the RCA shield have been blown up.
The amp is Philips xp480. I do not have the schematics.
Any ideas ?

Hello,

I'm about to build a box for two fane 12-250tc that looks like the first picture (150l, 40hz), but something bothers me. By putting all my box characteristics in a software like winISD or speakerBoxLite and looking at the cone displacement graph (second picture) it goes terrifyingly high.
I first thought that these drivers just can't handle such a big box but then I found this guy's build (link) with even more volume (90l. per driver).
Then I looked at fane's recommendation and they recommend a max of 75l. per driver but even with these numbers in simulator cone displacement gets crazy.

May it be that fane gives an xmax that correspond to absolutely 0 distortion (which I don't really care, it's for partys) and xmech is way higher ?
Or they expect us to not send full power with big boxes ?

Some help or ideas would be very appreciated 🙂

Hello everyone,
I have a csr8645 module attached to an breakoutboard with AMP.

https://de.aliexpress.com/item/3283...t_main.491.27b35c5fVA1k2c&gatewayAdapt=glo2en

I've put in in my old car radio and it works but when I pair bluetooth you hear popping/crack noise. Also when I start/stop streaming audio you can hear the noise after 3 seconds.
Other users had the same problem in this thread.
According to a user the problem seems to be that the chip disables the ouput stage when it doesnt recieve any audio stream.
I have a csr-spi programmer and I played around with a lot of settings (i.e. disable low power codec) but I could find a solution. Also using the mute pin of the board results in popping noise.
Does anyone know a solution how to keep the codec alive eventhough its muted on the sender? Can I solder some components to the amp circuit which could prevent the popping noise? Any help would be very much appreciated.

Attached is my impedance sweep of a Satori 9.5" WO24P 8 ohm woofer. This sweep was taken using Dats 3 with the woofer installed in its enclosure. As you can see, there are 3 distinct blips to the right of the woofer resonance curves that catch your attention. The blip farthest to the right at 1Khz also shows up in the free air sweep (not attached) so has nothing to do with my enclosure. I have no idea what this blip is from, but since it's well past my target crossover point of 500hz, I'm ignoring it. I'm not sure what the middle blip at ~700Hz is from, but I'm guessing it's my 6" long x 2" diameter vent tube. The 3rd blip at ~364Hz would appear to be a standing wave from my woofer enclosure. The enclosure is a roughly 1.4 cu ft cylinder with a 13.2 inch inner diameter.

I have no real idea if the amplitude of any of these blips warrant attention, but I decided to try to cut down the one at 364Hz as it's within my target crossover frequency. My first attempt was to install rockwool to see how well it reduces the standing wave. The rockwool I have is very fragile and didn't conform well to my enclosure. I covered the bottom and about half way up both sides of the enclosure and took another sweep. The amplitude of the blip at 364hz was reduced by about half, so I believe it is my enclosure causing it. I attempted to install the rockwool to the enclosure top, but only caused it to break into multiple pieces. At this point, I did more research and decided to remove the rockwool and try Acoust-X paint by Acry-Tech.

The first thing to know about this paint is how to open it. It has instructions on the lid, but they're not clear at all. What they want you to do is push down in the center of the lid while simultaneously prying up on the outer lid rim with a screwdriver. This works, but takes a lot of force to open. It can also be messy so wear gloves even when just opening the container. You should also wear gloves and ensure good ventilation when applying as the MSDS for this stuff has several health warnings (Including potentially being a carcinogen).

Next I used a small paintbrush to apply to all the inner enclosure surfaces. This paint is thick - much like a good thick milkshake. It does not go on well by using brush strokes. You're better off dabbing it on as brushing seems to just push it around rather than coating the surfaces. I put on 1 coat and left to dry. The container gives no directions relative to drying time, so I returned to inspect the coating after 30 minutes, 1 hour, 5 hours, and 24 hours only to find that the coating was still wet. I let it dry another 24 hours (Still wet), but applied the second coat anyway. In fairness, I was applying the coating in my cool basement, so that could be part of the reason it wasn't curing well. After applying the 2nd coat, I placed a small fan blowing into the enclosure. The fan was the trick as the 2nd coating was dry after 24 hours. I ended up putting on a 3rd coating to cover a few spots I missed and once again used the fan to dry (Waiting another 24 hours).

The instructions say to clean up with water, which works well. The brush is easy to clean and can be reused several times as a result of the easy water cleanup.

The 2nd attached file shows the Dats 3 impedance sweep of the woofer after applying the paint. It appears to have narrowed the frequency a bit, but also increased the amplitude. Again, I don't know how big of a problem this is, but it appears the sound damping properties of the Acoust-x paint did not improve (and may have made worse) the standing wave (If in fact this is a standing wave) problem.

I'd be interested to hear others thoughts on this and if you've tried this paint

I've just replaced the resistors in my three way speaker. I've moved from standard ceramic wire-wound types to Mundorf Supremes at a cost of £90...

I was expecting the sound to be much better, however, it is much worse - very disappointing. There is a slight increase in detail across the mid and treble - if I wasn't so familiar with my test tracks I wouldn't have noticed this. However, there is now considerable sibilance and treble 'wispyness' which wasn't there before. It is not making for a pleasant listening experience.

This may be that 'burn in' time required, if that is a thing. But as it stands I will chalk the cost up to experience and switch back to good old cheap ceramics.