Failed PS, and partial channel failure. Output set of TIP35C (2) need to be replaced. Also the BD911 output driver appears like the solder pads overheated slightly, but the component is still working. I'd like to pop that one out of course.

BD911 equivalent if possible? BD911 has about 3A SOA at -32v

NPN TO-220 On hand:
TIP102
MJE15030G
TIP41
2N6488 (2A SOA at -32v)

Will any of these work? I seem to recall seeing TIP102/107 as Drivers in some Zed amp's output stages, but it would seem that 2n6488 might work best data sheet wise equivalent.

Amp is running +-32vDC rail.

Thoughts?

I've fallen into the rabbit hole of building an array of SB65WBAC25-4 drivers.

My current main speker is a 3-way and the response differs a lot when not in the sweet spot. CBTs seem to perform well here but I like dipoles hence a dipole CBT.

I've based the speaker on the following papers by Keele:

http://faculty.tru.ca/rtaylor/publications/cbt_dipole.pdf
http://faculty.tru.ca/rtaylor/publications/dipole_cbt_implementation.pdf

I want to try a CBT-shaded 70 degree circular arc dipole with 22 drivers in each speaker. My experiments so far have shown promise.

The first image is the first prototype. When taking the photo I was comparing having half drivers inverted vs all same direction. All same direction outwards measured far better. The prototype has 4 banks, which I realized with 1 resistor and 3 channels.

The next step is to build the real ersion, I just got my package of laser cut plywood =)

Along the outer spine edges I'll glue a 10mm round alu tube bent to match the speaker and then cover the whole front with a layer or more of wool felt. Should give me at least 6 dB more efficiency on the low end. (I got 10 dB with only 4 drivers). And to make it look nice I want to try and see if I can taper the baffle width. In theory it will counterract the issue that around fs the driver impedance peak will overpower the crossover. The width of the baffle around each driver is proportionally same as the attenuation: half width equals half voltage.

The final speaker / next prototype will have, well, 9 banks of attenuation. I want to keep the attenuation at high fequencies so I've planned to add inductors to the 10 ohm resistors.

The attenuation is cosine shading like they used in implementation in the paper. I made a spreadsheet to calculate the attenuation for each driver: CBT shading - Google Sheets

Because I know nothing of CAD I wrote a python script that outputs a bitmap of all the parts, then I loaded it into Inkscape and converted it into lines. If anyone wants it I can share the code but beware, it is kinda ugly 😉

Hello there, I have read some posts with kinda the same problem.

No plug into input jacks or power amp jack, the amp makes a little hum that won't go away until I plug a cord, then the hum disappears immediately.

I have read this post from 2015:
https://www.diyaudio.com/forums/instruments-and-amps/200792-fender-frontman-212r-3.html

Here are some readings I took, from Q18, Q19, Q20, Q21
The schematic does not have readings, so I don't know if the values are ok.
None of the transistors get hot, just a little warm.

NO CORD/PLUG - READINGS:

Q18
B= 0.916V
C= 40.10V
E= 0.342V

Q19
B= -1.335V
C= -39.99V
E= -0.170V

Q20
B= 0.351V
C= 40.06V
E= -0.170V

Q21
B= -0.726V
C= -40.00V
E= -0.180V

WITH CORD/PLUG - READINGS

Q18
B= 1.136V
C= 40.16V
E= 0.547V

Q19
B= -1.137V
C= -40.08V
E= -0.538V

Q20
B= 0.542V
C= 40.06V
E= 0.008V

Q21
B= -0.535V
C= -39.99V
E= -0.001V

What should I look for?

Thank very much.

My 306 has a very soft “rattle” in the left channel, with the input disconnected.
You really need to put your ear close to the tweeter to hear it, however, the right channel is dead silent.
All power-transistors seem the originals, and the amp sounds wonderful.

Changing to another mains outlet did not work, reversing line and neutral had no effect either.

It’s not mains hum. I connected a scope on the speakers and saw little spikes of a few mV “traveling” on the output with 20-140 ms interval. These spikes themselves seem oscillations of approx 15 MHz. See screenshot (with NL comments, sorry).

A Quad-guru advised to change T7-T8, however, I do not understand that…

Any other suggestions? Thanks!

Hello.
Need help for find analog or original of 2 power transistors 2SC2565 & 2SA1095.
Very many fake .......
Thanks

Hi all
The above mentioned IC is not available at digikey or mouser. Is there any good replacement for the IC that is available in the market? Or does anybody know buying them from Chinese market is reliable for that particular IC?

Good evening all,

I'm hoping a few of the experts will chime in on this subject. I have looked at a number of posts similar to my situation but not identical. I am trying to build a tube preamp that can be used as a line stage or Headphone amp. About a year ago I bought an Aikido Noval (rev F) kit and a PS-21 power supply from GlassWare Audio. Based upon John's suggestions I will be using the JJ ECC802s in the first stage and the JJ ECC99 in the second stage. After I bought the kit I assembled the PS-21. Pretty straight forward. When I started the preamp board things got a lot more confusing for me for 2 reasons. First in the manual there are charts for different tubes....the ECC99 is not in the table. Moreover the ECC802s is not either. I do understand the 12AU7 and the ECC802s are interchangeable. Secondly, when doing double duty as a line stage and a headphone preamp the values of the parts change or are eliminated or jumpers are put in. Very confusing when my combination of tubes are not addressed specifically in the manual. I have tried emailing John a few times but I have not heard back from him.

What I do know: I have 225V coming off of the PS-21 for B+ and 12.6V for the heaters. I have 33uF caps for the 300 ohm headphones and 1uF caps for the line stage. Beyond that things get hazy for the above mentioned reasons. As I said, I did try and look at a similar post (Aikido Noval Rev G) but the schematic labeling is different enough that it doesn't quite make sense. I am no expert when it comes to tubes so I am hoping to rely on some expertise here. I was hoping for a kit I could assemble (easy enough) and listen to. I feel like I have to know preamp design at this point to make any progress. Well I have rambled on so I am going to end it here. Feel free to ask questions if I missed something important.

What are the best sounding dual opamps (plural due to subjectivity)? Preferably in DIP-8 package.

I have always enjoyed OPA627/37. However, due to space constraint, I can not use them in my headphone amp (the browndog couldn't fit). Currently, I have AD826, OPA2604, and LT1364, all of which are excellent but not in the same league as OPA627. Any suggestions? (and where I can get them, if they are hard to find in the US). Thanks!

I encountered the CrossOver Distortions at Audio Research Preamp SP-4.
See attached picture。

The SP-4 Preamp is using Audio Research Analog Modules。

Need help to resolve the mentioned problem。

Thanks,
Peter.

Hello everyone!
This is my first thread here so I hope I am in line and I start a valid conversation that hasn't been discussed too many times. I have photos of my measurements attached, even though I am not sure this is the proper way to post photos in threads.

I am designing and building a Class AB output stage for a solid-state guitar amplifier. The design uses lateral MOSFETS as output devices. I used the Exicon ECX10P20 / ECX10N20 pair. I have attached a picture of the schematic below.

My problem is with the gate resistors, commonly known as gate stoppers. They are supposed to kill the speed of the MOSFET, insulating the capacitance of the gates from the VAS stage, thus avoiding HF oscillations, before they even occur.
However that is not the case in my spice simulation. All the tests in LTspice show better stability without these resistors. First of all I measured the gain margin without gate stoppers to be 8.5dB and with 221Ω gate stoppers to be 5.5dB. The phase margin without gate stoppers is at 83 degrees and with 221Ω gate stoppers it is at 81degrees (for more information on gain and phase margin refer to Bob Cordell's book "Designing Audio Power Amplifiers" - particularly chapter 4.3).
Another test that confirms my suspicions is a 20kHz square wave response measurement. To reveal the problem I made the Miller compensation capacitor Cm intentionally small, reducing it from the proper value of 220pF to 22pF, allowing oscillations to happen. The "ringing" in the edge of the square wave is hint of instability. I ran the simulation without gate stoppers and then with 221Ω gate stoppers and I have the results below. The "ringing" is much worse WITH the gate stoppers. I have also attached pictures of these measurements.

These results are very much the opposite of what I expected and it is very concerning, bearing in mind that most people are quick to point out that gate stoppers of hundreds of Ohms are ABSOLUTELY NECESSARY in MOSFET power designs. I am currently building the amplifier and I have to decide on values.
Please help. Any idea what's going on?

Hello,

I'm ready for a build that calls for both a regulated 24 volt and a regulated 12 volt for the circuit. I have on hand an all in one 24 volt regulated supply but will need to create the reference 12 volt from this supply.

I was hoping some of you might steer me in the direction of how to look at providing the circuit with a regulated 12 volts.

While certainly not being any expert in circuit design, I entertained the possibility of first using an 18 volt regulator as the first stage, then feeding the 18 volt regulator output into a 12 volt regulator. This was an attempt to not give each regulator an input voltage that would create alot of heat dissipation, that 2 regulators could share the dissipation as the 12 volt regulated voltage was created.

I realize this is probably silly but, since this a one off project, I figured I could afford to be silly while hopefully being more nice to the regulators giving me the 12 volt regulated reference voltage along with the 24 volt regulated supply voltage.

Is this any kind of a workable solution?

thank you for your input.
Best,
Phil Donovan

Just for info realy for anyone who has ever tried to find these, and had trouble.


They are so tiny i needed my big magnifiers to see them, and remove them


so here are a couple of close ups for reference in case anyone ever needs them🙂

Hello,

I'm hoping to avoid having to buy a big SEOS 24" or JBL 2384 horn for my 1.5 inch exit JBL 2452 driver, but ideally wanted to get down to 600hz for the crossover. This task is seaming rather impossible, with the end game likely being a DIY route.

Couple of questions on ZXPC horns:

I'm aware of the 18X10 ZXPC horn,, but has anyone measured the 17 X 11 ZXPC horn?

11" x 17" ABS 2" Bolt-On Long Throw Horn 90deg x 40deg For Many 2" Exit Driver 647356202421 | eBay

The dimensions of the horn are all different from the 18 X 10

Also, what is the usable frequency cut off for either the (well measuring 15 X 9 (klipsch 510 copy) or this one?

Thanks ��

Sold

o, I managed to get all kinds of used goodies: A Dynaudio Esotar2 1200 subwoofer, Esotar2 650 woofer/mids, ScanSpeak illuminator tweeters, and a pair of Morel Ultimo TSCM 634 midranges. I've also got a SB Acoustics with a much smaller sealed box (nothing built for the 1200 yet), a JL Audio RD900/5 amp (bridged, powering the Morels and Scans in parallel, with a Clarity-Cap protecting the tweets), the little sub plugged into the sub channel, and a JL Audio RD 400/4 collecting dust until I get the wiring done and I can tune everything with the Audiotec Fischer Helix3 DSP, Director, BT unit, and its calibration mic and software.

I also have two Kenwood Excelon media players, for my Highlander, and my older CR-V (my beater). I want to make sure my wife has the most phenomenal-sounding system.

I realize the JL's are probably the bottleneck of all this, and eventually I'm going to obtain Morel Piccolos and Dynaudio Esotar 110 tweets. Question is; do I put it all in my wife's Highlander (rear fill), or would I be wasting good equipment that way for little return? Custom enclosures, or angled ABS enclosures with Dynamat in back of them? Any other polite advice would be GREATLY welcomed! Thanks guys!

What commercial amps (if any) come with decent components and build quality?

For example, if someone were looking for something with the performance of a decent NAD amp (let's call this "solid, but not really earth shattering") but without the stupid implementation failures (like putting electrolytics next to hot components, or hot components so close to the board that they turn the PCB into a crisp) and without the bucket of crap brand capacitors that give out and turn the whole thing into a doorstop after a few years... What might they be looking at?

Hi, i am looking for one or two pcb boards of Peeceebee V4H power amp, preferably shipped from Europe to Greece.

I'm resurrecting my old TD160 super. Now there are plenty of suggestions online how to improve a standard TD160, but many of these enhancements were already done by Thorens on the TD160 Super, including:

-Bituminous felt damping on the motor board and suspended subchassis
-heavy duty bottom plate made from thick MDF
-larger main bearing

Now I notice this TT still suffers from noticeable microphonics when in operation - any minor disturbance of the motor board are easily audible.

I'm looking forward to suggestions please to improve this deck without going overboard with major modifications. Some ideas under consideration:

-A new solid hardwood plinth noting the existing is MDF. I'm considering this more for aesthetics as the existing MDF plinth is pretty rough - however I don't want to do this at detriment to the sonics. Does the plinth material impact the overall tonal qualities of this deck? Is hardwood appropriate? There are plenty of aftermarket plinths on the market, suggesting this may not have a bad impact. I will make my own if I go down this path.

-damping the arm board. My existing armboard supporting the SME3009 tonearm is plain aluminium sheet, with no damping at all, and no damping in the steel spacer/screw attachments to the subchassis. I've applied Response damping material (similar to dynamat) to the underside, and am considering using o-rings on the spacer to subchassis mounting points for some additional isolation. Thoughts on this approach?

-is damping of the inside of the sub-platter recommended? I can use my Response material for this.

-I have the factory black rubber platter mat. Suggestions please for the best isolation here - I suspect this may be one area of huge possible improvement.

-is it worth replacing the factory bituminous felt damping on the motorboard and subchassis with something else?

-any other suggestions whilst I'm in there?

Hi friends.
I have seen threads regarding this topic.
But I am still not clear about the connection of pin 8 on the 6E6P-DR valve in triode mode connection.
Is pin 8 connected to the cathode?
It is connected to ground?

Two brand new matched pairs of Tokin THF51S for sale.

Asking £250 per pair, including original mounting bolts and thermal interface material, free shipping worldwide.

I have a pair of 12 driver (shaded)line arrays using Tang Band 3" drivers that have problems with failing treble response on and off axis (due to driver response and comb filtering). Otherwise I really like the sound, esp. in the midrange.

I'm looking to add a tweeter. I have a nice extended-sounding pair of Infinity Emit-k on hand already (I also have a pair of PT2C-8, but they're huge). I tried the Emits with a simple, series cap, and liked what they added(but the breakup of the TB's was still there).

I was thinking of removing one 3" driver (at ear level), replacing with the Emit tweeter. But that probably won't be a good sensitivity match. So another approach waits
Any recommendations?
🙂 Thank for any ideas,

-Charles

I have one of these mono amplifiers which has stopped working.

The culprit is the inputboard, which is very hard to both troubleshoot and repair. Does anyone of you readers know where I can source a spare part? (The amp was bought in DK, but the importer went bust and has disappeard!)

Many thanks.

Hans Jørgen

I have for sale one 600VA 4x40Vac 1x230Vac toroid transfomer. It was made special for audio applications (optimized magnetic performance of core for lower noise).

Price: 75 EUR + post costs. Payment via PP. Dimensions: 140x70 mm.

I have for sale one assembled (not tested) PeeCeeBee power supply. It consists of original BOM components, Omron G2RL-14-E-CF relays, RURP 1560 power diodes and 4x15000uF 63V Elna capacitors (not soldered). Buyer only needs to add relay resistors (value depends on transformer voltage).

Price: 85 EUR + post costs. Payment via PP.

Hello all !

I am planning to build a valve PP amplifier, around GU32 power tubes. Ideally I would prefer to use 6N2P/6N1P or 6N7S as I am having some of them already. On the other hand, any russian series tube will do.
I have been searching for schematics but couldn't find anything suitable.
Need to mention that I am looking to use 2XGU32 for each channel with paralleled sections.

Thank you in advance. 🙂

I have for sale 4x15000uF 63V Elna audio capacitors, snap in, dimensions 35x50 mm, never used.

Price for set (4 pieces) is 35 EUR + post costs. Payment via PP.

Learning bits by bits how to make a simple two way loudspeaker (15'' woofer & 1.4" CD + horn).
I have the box design covered with the great tutorials from the pinned thread (volume, ports, frequency...etc).

I don't know where to start with baffle design though: where to place the woofer, what distance should it be from the edge, what distance should the horn be from the woofer, etc...

Here is what I think I know so far:
If I let Fmax be the maximum frequency I will use the woofer, the distance between the edge of the woofer and the edge of the box should be 1/4 of the Fmax wavelength. (for instance, ~10cm for 750Hz)
I should round the edge to minimize diffraction.
The Fmax should be where the directivity of the woofer starts to diverge to get a nice transition with the horn.
On the other hand, I have no idea what should be the distance between the edge of the woofer and the bottom of the horn.

Thanks
luc

Hi,


I hope this is a good place to ask.


I have a '99 Range Rover, that stock came with an Alpine head unit and a separate amp that drives the speakers.
For this reason I've been putting off getting a new head unit, as one with an unamplified output seems to be rather hard to find, especially reasonably priced.


Recently I came across this product from InCarTek, that bypasses the amplified speaker output, and plugs them into the head unit's pre-amp output. Great!


So yesterday I tried connecting everything, and while it works fine, there is a hell of a noise in the speakers. A bit of debugging later showed that this only occurs when nothing is plugged into the head unit's speaker plug, even when the pre-amp plugs aren't even connected.
This noise is gone if I plug directly into the speaker output, but then there's the dual-amp hum, and barely any volume adjustability that I wanted to prevent in the first place.

It seems to me the head unit is kicking out a bunch of noise in the power wires if there is no load on the speaker output.


Does anyone know of a solution to this? I've been trying to do some googling, but not getting many answers. A simple solution seems to be a dummy load, but a 4-8 Ohm 70W resistor is going to be a beefy chonker putting out lots of heat.
Or maybe a recommendation for a head unit that either doesn't have amplified outputs, or where they can be turned off (preferably reasonably priced...)?



Thanks in advance for the advice.

Uniti Atom.
Functions normally when first turned on, with a quiescent mains draw of approx 50ma (@230v input)
When it warms up, I get a 0.5volt 4MHz oscillation on the L channel output and the quiescent mains draw goes up to 300ma.
This, of course , leads to further heating (even with no input signal) until eventually the thing is too hot to touch.
Anyone seen this?
M

Hi,
I checked and can't find my old email address on my profile, but the newsletter about the upgrade went there as well as my present one. Not a problem for me, but is that intentional?
Thanks,
Ian

I've had these drivers for some years and like them quite a bit, the only thing nagging me being their noticeable beaming, somewhat pronounced for a 4"-class driver IMO.

I've never measured their parameters and always designed for them based on the datasheet. I used to use ARTA/LIMP, but having moved to Linux, I switched to REW. I measured almost everything I have for fun and in order to learn the software. Here's what I got for each of my two units, I post this here for general interest, as this is still a current production model, at the date of this post.

Driver A:

RDC 6.30 ohm
Re 6.11 ohm
Le 0.156 mH
fs 87.0 Hz
Qms 2.823
Qes 0.606
Qts 0.499
Mms 4.57 g
Cms 0.732 mm/N
Rms 0.885 kg/s
Vas 3.38 litres
Bl 5.021 Tm
Eta 0.36 %
Lp (1W/1m) 87.70 dB
Dd 8.52 cm
Sd 57.0 cm^2

Driver B:

RDC 6.30 ohm
Re 6.21 ohm
Le 0.163 mH
fs 87.2 Hz
Qms 2.839
Qes 0.589
Qts 0.487
Mms 4.69 g
Cms 0.711 mm/N
Rms 0.905 kg/s
Vas 3.28 litres
Bl 5.206 Tm
Eta 0.36 %
Lp (1W/1m) 87.72 dB
Dd 8.52 cm
Sd 57.0 cm^2

Datasheet:

NOMINAL IMPEDANCE 8 ohm
DCR IMPEDANCE 6.3 W
SENSITIVITY 1W/1M 88 dB
FREE AIR RESONANCE 75 Hz
FORCE FACTOR, BL 5.31 TM
MOVING MASS 3.99 g
SUSPENSION COMPLIANCE 1134 uMN
EFFECTIVE PISTON AREA 0.0057 M
Levc 0.026 mH
X-max 3 mm
Vas 5.23 Litr.
Qts 0.36
Qms 2.52
Qes 0.42

The good thing is the data is quite consistent between my two units. Fs, Qes and Qts are noticeably higher than factory data. My lower Cms figure might explain the higher Fs. For some reason I read very high Le figures on all my drivers, not sure why. My impedance jig and software are fully calibrated. You can probably disregard my above measured Le.

Edit - I did not actually measure higher Le, the error originated in the driver's seat, who had not yet learned to properly read REW's export formatting. I corrected the values above.

I am working on a center channel design to blend with my Zu Audio Essence speakers, and would like to share my ideas to get some feedback from the forum. With all of the possibilities I would like to narrow it down and get to building and testing!

Drivers:

2x Satori MW16P-8 6" Mid woofers
1x Fountek NeoCd3.0M-blk 3" Ribbon Tweeter

Enclosure:

3/4" 12 ply birch plywood, sealed ~16L based on UniBox simulation, with felt lining with acousta stuf final amount to be determined based on measurements. 3/4 chamfer around baffle. External dimensions 17.5" wide, 9" high, 11" deep (I know this is closer to 18 l).

Driver alignment:

Horizontal MTM 5" CTC across all drivers, with tweeter above center axis of woofers in a high nested mounting location. I am open to other alignments and have also been thinking about a 3-way design with the Satori MD60N-6 2.5" Textile Dome Midrange.

Next steps:

I plan to build the enclosure soon, then measure to see where I am at.

One goal is to have decent dispersion.

I am planning the crossover ideas, and would like some feedback on some of the ideas:

1. 2.5 way vs 2-way.

I have been thinking about a 2.5 way design to help avoid some of the issues with a horizontal MTM. However 2-way crossed over around 2500 seems simpler. I have been modeling these ideas in the Jeff B spreadsheet.

2. Super simple crossover vs. higher orders.

Since the Zu 10" woofer runs full range and the ribbon only uses a single 1 mf cap, my first thought was to run this center channel in a similar way, but I have become concerned about this design in terms of various cancellations / combing / lobing etc.

I next started to model a 2.5 way design following the tweeter manufacturer cross over recommendation of 3rd order @ 2500hz, with one woofer as 2nd order @2500 hz with the other woofer at a frequency of 1875 hz or lower. I have read that mixing the crossovers on an MTM as 3rd order tweeter / 2nd order woofer can be good for dispersion though not sure this applies to a horizontal MTM.

Finally a straight up two way crossover 2nd or 3rd order for tweeter and 1st or second order for woofers at around 2500-2700 hz.

I would like the crossover to be minimal, however appropriate. The models suggest calming the tweeter with an l-pad.

As for the crossover software, how much can it be relied upon and how important are the phase and impedance curves? Phase slopes should slope evenly across response? Use Zobel to tame impedances, what is too high for impedance across response?

Any thoughts, experiences, or feedback on this design or similar designs?

Thanks!

Chris

I have a design question. Working on a buffer and tone control.



I have two dual-op amps U1 and U2 for a total of 4 devices.


Should I design my circuit so that U1 does everything left channel related, and U2 does right channel...


OR should U1 do the buffer for both channels and U2 do the tone control for both channel, thereby splitting them by function.



I'm tempted to have each op amp do their own channel to minimize the possibility of channel crosstalk and therefore imaging improvements, however, I can't help but notice a nagging feeling that there's a pitfall somewhere with this theory...



Please advise!

When you listen to live music, for example a drum kit, the sound levels at times can exceed 100dB close up. Orchestras are even louder. The power of live music is one feature of live music, there is the sheer smoothness or linearity or fluidity of the live voice or instrument, missing the granularity I hear or imagine I hear from music reproduction.

Now playing music in the average living room I will not or cannot play back at such high sound levels, or maybe at the (guessed) mixing levels. So at one go, the accuracy of the reproduction is diminished. It is like listening to a band playing in the distance but that also introduces echo and wind effects.

What I hear then is a miniature version of the recorded music, even if I compensate for loudness effects.

Aren't we listening to miniatures of music rather than music? How to equalize this so it resembles as far as possible what the live listener hears or recording studio monitors put out?

As I delve deeper into building speaker cabinets and testing micro power amplifiers, these questions seem to spring up from time to time.

Sharing time. I recently finished the build of my third OTL headphone amp. First one had a SS output with tube input, second was a SRPP+ build. Latest is an ECC99 White cathode follower output with a 12AT7 as input tube. It's loosly based on the 'Morgan Jones' headphone amp, with lots of tweaked resistor values, alterations to accommodate the ECC99's and some other things. The WCF is partly LED, partly resistor biased as a compromise between distortion, dissipation and output. HT and the input tube's heater are regulated, the ECC99 heater's are AC, mainly to the current demand.

Some measured figures. All into 47 ohms resistive load @ 1kHz (if applicable):
THD: 0.017%
THD+N: 0.96% (needs work)
Output impedance: 5.6 ohm
Freq response @ 20Hz: -0.065dB

Oh yeah, and it sounds awesome!

It's still a 'prototype' so no enclosure will be build. So I had to find something that was cheap, available and easy to work with. LEGO! I still have loads lying around, it's an electrical insulator, and can stand some heat. Perfect. I felt like a child again, sore knees and all 😀

The pic with the open enclosure is (obviously) with temporary output caps.

When using a voltage divider from B+ to elevate heaters is there a preference to where the divider is positioned with respect to the power supply origin? In other words do we put it close to the initial filters so that any AC heater hum leakage is treated by subsequent filter (decoupling) sections or toward the other end (amp input stage) so that the bias voltage has maximum filtering?

This example shows the latter condition (right above the volume pot in the drawing).

Hi.

Been looking all over for some answers to what would work as a damping spray/paint/coating for the interior of the enclosure?

Not sure if this is even something that should be done?

Not like it'll be easy to remove once applied.

I've built two sets of speakers from plans off the Frugal-Horn site Double mouth BVR's

(Kongo and Kirishima)

Want to coat the interiors to deaden the "boxes"

Has anyone done this?

If so, what materials have been used and to what effect?

Thank you in advance,

Per

With the UK live music scene comatose, I have chosen to create (yet another) portable system for myself and some others to enjoy as or when we can.


Below are the specifications with my current projection below:

1. Volume must fit inside a large backpack. Maximum 60L.
Fits in backpack, enclosure volume measured 57L

2. Weight must not exceed 10kg (excluding backpack itself)
Current complete mass estimate 9,5Kg

3. Weight distribution must allow full days hike
Check (good CoG/MoI)

4. Low extension F3 60Hz
Current F3 = 60Hz , F10 = 47Hz (winISD)

5. Simulation peak SPL to hit 116dB at peak, 110dB 50Hz
Current max SPL = 118dB (winISD), 50Hz = 110dB

6. Power distribution must be 90 horizontal x 70+ vertical. More the merrier.
Constant directivity horn supports this

7. No enclosure modes or resonances
Current modal analysis moves all fundamentals 400Hz+

7. Battery is to last 4hrs at full pelt, 12hrs at 100dB (sim)
Estimated life at full = 5.5hrs, 100dB = 22hrs.

8. DSP on board w/ missing fundamental
Check


Here is the current plan for the build:

Electronics
Power source: 36v 354Wh ebike battery (already owned)
Amplifier: 3e TPA3255
DSP: Sure ADAU1701 (already owned)
Buck converter (option to bypass, only used if want to sacrifice battery for a couple of dB): 400w Chinese module (already owned)

Drivers
LF driver: 1x B&C 12CL64 (1.9kg! BL:17.5, qts: 0.3)
12CL64 LF Drivers - B&C Speakers
HF driver: 1x B&C DE111 (320g! 1.2kHz full power XO)
DE111 HF Drivers - B&C Speakers
Horn: 1x RCF H100 (800hz cutoff, 90x75, CD)
Product Detail - RCF

Enclosure
Material: Poplar plywood, 9mm
External dimensions: 65 x 35 x 25cm
Coating: PU laquer
Tuned: vent at 60Hz
Build methodology: Braced as per FEM and battened at edges (18mm glue area)


How do you all feel this is as a plan to hit the specifications? Is there any other creative approach you would consider?

The LF section is of course the limiting factor for both battery life and SPL. I have looked at BP6 and tapped horn (such as cubo12) arrangements, but I am struggling to get any to work better in the 45L range. As per equal loudness and directivity, I expect around +12dB of gain to be added around 60Hz to keep it sounding 'full' outdoors

Otherwise, would you rather pair the LF with a 5/6" midrange driver (eg B&C MDN38) and tweeter (eg P-audio PHT-407N) with a passive XO? Do you feel the integration or intelligibility would be worth the extra cost and complexity?

Cheers,

Hi guys I’m new on this forum, I’m an owner of B&w matrix 800 speakers and im looking for spare tweeters or woofers for the matrix 800 speakers thanks

Hi everyone.
I have a project where I need to connect my laptop to 10 different guitar amps.
My idea is to buy an audio interface with 10+ outputs (I don't really care about inputs)

For example, I found those :
Behringer UMC1820 – Thomann UK (10x 6.3 mm jack line outputs (1 + 2 monitor output L/R))
Tascam Series 208i – Thomann UK (2 Balanced TRS main outputs with front level control + 6 Balanced TRS outputs + 2 Stereo headphone outputs)
ESI U108 PRE – Thomann UK (8 Balanced line outputs: 6.3 mm TRS + Stereo monitor outputs: 2x 6.3 mm jack + Headphone output: 6.3 mm jack)


My question is, with those kind of audio interfaces, can I send a different audio signal to each output channel? I guess(and hope) the answer is yes. But I really need to make sure about it before buying anything

Thanks in advance for your help!

Hi all,
I got a speaker that i want to modify. I want to pop the battery and an amplifier in it. Please could anyone help me what amplifier could run this speaker? Preferably bluetooth 5.0 if possible and I think It should be mono as well. The speaker is Identical like the one on the picture and woofer is 4ohm 50zt-1, mid is 8ohm 20 vt-5. I dont know what vt and zt mean tho.

Acoustic Reference SM-1000 3 Way Speakers Black High End Very good condition | eBay

Preferably I would like to buy something local (UK) if possible rather than wait from aliexpress, but if I have to order from ali thats not an issue.

If anyone can help or has a suggestion please post it.
Any help in this matter is appreciated

It's a commonly held opinion that a Hurst 300 RPM motor is an upgrade to the stock 600 RPM motor used on a lot of tables. The reasons most commonly cited are:

1. Higher torque
2. Lower vibration due to finer cogging as a result of 24 poles vs 12 poles.

1. While it is true that a 300 RPM motor will have twice the torque of a 600 RPM motor of the same power rating, the 300 RPM motor will require a pulley twice the size of a 600 RPM motor and have 1/2 the mechanical advantage, so the force (and therefore usable power) delivered to the platter, will be the same, assuming the same power rating in the motors. The downside of using the 300 RPM motor is the speed mismatch at power up between the pulley and platter will be greater than with a 600 RPM motor, so the "burn out" on the belt will be worse. It is analogous to trying to start a car moving from a dead stop by starting in 2nd gear (300 RPM) vs 1st gear (600 RPM).

2. Cogging is caused by the strong attraction between the permanent magnet rotor and the metal pole pieces and loss of attraction between the rotor and the air gaps between the poles as the rotor spins. The cogging feels "finer" in the 300 RPM motor when turned by hand because there are twice as many poles, but the motor spins at half the speed, so the frequency of the variable reluctance "cogs" will be the same: 5 revs/sec x 24 poles=120Hz for a 300 RPM motor and 10 revs/sec x 12 poles=120Hz for a 600 RPM motor.

Assuming the same strength of the PM rotors and the same clearance between rotor and poles, the strength of the cogging (and the amplitude of the vibrations) will be determined by the strength of the rotating field in the coils which is a function of the electrical power rating of the motor. A 300 RPM motor should have the same vibration signature as a 600 RPM motor of the same power rating.

I did some tests using an Analog Devices ADXL327 three axis accelerometer mounted directly to the ring on a VPI SAMA housing, using 3 Hurst motors: 5.5W 600 RPM, 7.5W 300 RPM and 10W 600 RPM . The tests were done with the motor firmly mounted in the housing, pulley installed (but no belt) and using the factory supplied (and recommended) phase cap. I even took care to place the SAMA at the same locaton on the bench which is 1½" maple butcher block. The ADXL327 is powered by 2 Lithium Ion batteries.

The first image below is the baseline reading: ADXL327 powered up and mounted on the motor housing with the motor off.

The second image is with a 5.5W 600 RPM motor with 0.5uFd phase cap. The primary response is at 120Hz as expected and the level of vibration is -52dB or 28 dB higher than baseline.

The third image is with a 7.5W 300 RPM motor with 0.68uFd phase cap. The primary response is also at 120Hz and the level of vibration is -48dB or 32dB higher than baseline and 4dB higher than the 600 RPM 5.5W motor.

The fourth image is with a 10W 600 RPM motor and 0.82uFd phase cap. The primary response is 120Hz at -43dB, 37dB higher than baseline and 5dB higher than the 7.5W motor.

The last image is a 12W 600 RPM BLDC motor driven by a 3 phase sinewave supply at 20Hz. The response at 60Hz was there with the supply on and off so I assume it is being induced into the wiring. The primary vibration from cogging would be at 10 revs/sec x 4 poles=40Hz and appears to be the same level as the baseline reading.

I don't have a dual motor assembly to test, but if the trend follows, the two 7.5W 300 RPM motors (15W) should have more vibration than the 10W 600 RPM motor. It is difficult to see why people consider the 300 RPM motors an upgrade from the 5.5W 600 RPM stock motor. The downside is the 300 RPM motors have higher vibration (as they are higher power) and cause more burn out on the belt. I don't see an upside.

Hi all,

I make small funky speakers using eBay chip amps, and have really been enjoying it! There's a 50w/50w amp board with a single volume knob and bluetooth that Ive used a lot - mainly because it will go from 5v to 24v so can be powered from a variety of sources.

However, I find myself wanting to add a single mono sub to my designs but its not easy to see just HOW i can do this without things getting much more complicated. I know there are 2.1 amp boards out there (and for not much more money that the one I use) but they don't work down to 5v, which I really want.

So, how can I make a 2.1 crossover? I always thought such a thing MUST exist as I had a passive sub back in the day that had stereo inputs and stereo outputs, but I can't find such a thing "ready made" for the life of me.

Any ideas for a circuit?

Regards,
Jim

Hello,
This is my all time favorite sine generator. In fact, it is not doing this equipment justice, just to call it sine generator. For example, the compressor (feedback) function is super handy if you want to compensate the irregularities in the driving transducer and measure the frequency response of an -say- accelerometer.

Anyways, it was in total dark, cold, non-working state when I received it. Fixed the power supply to generate the needed voltages without any ripples and discovered that, it is working in a narrower frequency band than the usual 20Hz to 20kHz. The sweep cuts early in the low frequency direction (nothing below 80Hz) and at high frequency region, there is nothing above 15kHz. The digital display goes dark at both directions and it cuts out the output. In between frequencies, everything works perfect. Frequency is spot on, output voltage is exact.

The only service manual which is on the web has the signal generation schematic blurred, I can not make out anything from the values or component IDs. Also, there is a mechanical switch that stops the generator when the dial is turned outside the scale limits. I have checked that and there is nothing wrong with its' operation.

Any idea, on where to start troubleshooting this problem, would be very much appreciated. Needless to say, I have already replaced the electrolytic and tantalum capacitors.

Thanks in advance,
Dirk

Free- Pick up in Ventura CA 93004.

Hi all,

I'm busy putting together a dummy load for testing headphone amplifiers. The necessary resistor values are straightforward enough, but I'd like to add some reactive loads that the headphones themselves as well as their cabling would present.

For capacitance, I'm thinking selectable 100pF, 220pF, 470pF, 1nF , 2.2nF and 4.7nF should cover things. Any thoughts here?

Inductance I'm less sure of - what sort of values would headphones likely possess?

It looks like Apple Computer has embraced:

1) horns

2) coentrant horns

3) phase plugs

Here's the patent they filed about seven months ago:

US10728652B2 - Adaptive array speaker
- Google Patents

This is a looooooooong patent.

From what I can see, the most obvious improvements are that the seven mid/hi drivers have a more sophisticated phase plug than the previous design.

From the looks of the BEM sims in the patent, it looks like Apple is trying to create a ring-shaped wavefront at the exit of the horn at the base of the Homepod. The idea is to basically have the Homepod behave like a ribbon tweeter, except it's a ring-shaped ribbon tweeter. Of course, the advantage here is that you can have the speaker play omnidirectionally, but you can also 'aim' the sound.



Bang & Olufsen got here first, in 2006. I met Geoff Martin when he demo'd these for the first time. (Had to sneak in to the demo, I am a scofflaw!)



A year later, Harman showed off Horbach's SL-1

Apple is also using asymmetric pathlengths. IMHO, this may be a tip of the hat to Alexander Voishvillo over at Samsung/JBL/Harman. They're using asymmetry all over the place these days. I'm guessing they're doing this to reduce resonant peaks in their phase plugs and waveguides, as symmetry often contributes to resonant peaks and dips. (Same reason the Danley tapped horns are smoother than a conventional FLH of the same size.)

Some JBL designs:





Cool stuff. Who would have ever expected Apple Computer to be selling horn loudspeakers?

Got a 1971 Peavey series 300 bass amp that has 2 4200 MFD 50 vdc can capacitors. The ends are bulging so thought I should replace them. Local electronics store suggested electrolytic caps with same capacitance and voltage but the fuse blew when I connected them. Is there a difference between a can cap and an electrolytic (besides size). Thanks.

Up for sale from Italy

4*CIARE CT200

2*CIARE HW100

2*CIARE HW204

300€.

Shipping cost depends on location.

Up for sale 12 pz
Itelcond 10000 uf 350V

Hello everyone.
There is such a Jurko project, what do you think about it?
How does he compare to Kalasan and Kairos?
JurKo :: Pkaudio

I'm putting together a single-ended and balanced selector switch (it's basically two separate switches in one chassis). There are five possible outputs however only four are being used and there is no mechanical method of reducing the possible positions in these selectors. Should I be placing a 10K ohm or so resistor across ground and signal on the unbalanced side, and anything on the balanced side so there is some dummy input impedance? ...or should they just be left empty.

Thanks very much for any suggestions!

YCLD - Dynamic transcoding and convolution in Logitechmediaserver

I'v always liked the idea to have the option to transcode AND apply convolution in LMS without many headaches. ATM there is C-3PO as a plugin for transcoding (but not optimal for convolution) and the hacked squeezelite SuperPlayer (I love it but it breaks the client-server paradigm where all the load should be on the server).

So I decided to make my own wrapping all the SoX + CamillaDSP logic.
I based it on a previous software which I made for batch audio file conversion (Recursive Audio Converter GUI) and I basically add to it the option to read and write from/to pipes and to read wav headers .

It is ugly, it is in beta and it has bugs.

Installation
Download and untar (Link at the end of the post)
Make sure to have OpenJDK >= 11 installed

Usage
Bad news! Fot the moment you'll have to edit your custom-convert.conf file. I know it is a pain in the *** and I'll try to help anyone but even for me this lms file is dark magic. Later I'll made a GUI (Desktop/web/mobile or whatever).
Before anyone asks me : no, I won't write an official LMS plugin, I'll start writing PERL code in my life only for at least double the hourly wage I take now as a dev. (what an ugly language)

First Example:
Explanation:
For whatever input flac file (also from Tidal or Qobuz), upsample it at double its current sample rate (ex 44100->88200) and then search in the convolution folder for an impulse named impulse{target_sample_rate}.bin/dbl/txt. In this case with a 44.1 input it will pick /mnt/music/0000-EQ-FILES/LCD2/impulse88200.dbl

Second example:
Explanation:
It will take the input file, apply convolution (with pcm->dsd the impulse MUST be at 352.8kHz) and then convert to DSD128

The possibilities are quite infinite, you can even do DSD64 -> convolution -> DSD256 (internally it will do DSD64->64/352k->HF fir filter->your custom fir filter->DSD256)

Config
In the tar.gz you'll find the main jar and config/config.properties

Example with comment:

Currently tested on Debian and FreeBSD. It should work on Win. Don't know about MacOS.

Downloads
YCLD download -> YCLD

Pre-compiled sox binaries with dsd support -> SoX

Pre-compiled CamillaDSP binaries (only with options needed by YCLD)-> CamillaDSP

If downloading from unix* command line --> curl -A "audiodigitale" -o /path/YCLD.tar.gz https://etc.etc.etc

Don't thank me, thank CamillaDSP and SoX devs and maintainers, and offer them a coffee.

Why YCLD ?
Easy! YourCpuLooksDelicious! Try to run it with both convolution and DSD upsample enabled and you'll understand

Tektronix 120-086 transformer
Hello guys,
i'm not sure if tube section is the right place to start the thread about a Tektronix transformer i just bought for 40,00 €

Pic or it didn't happen ,right ?

The Tek part num. is 120-086 , the guy who sold me the thing told me it was salvaged from a 541 o-scope and service manual show that is true.

So i have all the voltages from the servie manual but no current ratings, except heater windings.

I could use the voltage drop on the series 10 ohm resistors stated on the service manual, but i think this monster is capable of more than this. Dimension and weight tell me this Iron is around 500VA and more...


Anyone can give me advices ?

Also would you rather use it for a tube amp or to make a bench supply ?

Hello!
I need a pair of them, Please let me know if you a pair, to spare!
Condition-Fully functional and physical is great condition.

Luxman's 22.4kg, ~$17,000, D-10x SACD/CD player uses ROHM Semiconductor MUS-IC BD34301EKV . A 768kHz sampling, 32bit ⊿Σ Stereo Audio D/A Converter.
ROHM Musical Device: MUS-IC




This may be their first step into high-end audio dacs, tho' the Japanese company has been around since 1958. Rohm - Wikipedia

No price or datasheet info seems to avail, but a shorty summary pages is on Mouser.
BD34301EKV High-Performance Audio-DAC - ROHM | Mouser

Hello,

They gave me an amp from the late 70s and it is an Inkel AK-650. The device is very cool but at the having been in a carpentry shop for 10 years I have had to clean it thoroughly. The fact is that going through the circuit of the amplifier stage there are burned resistors (nothing serious) and the output transistors of a channel are also kaput. They are a Bjt B557 pnp and its complementary D427npn, totally discontinued. In the channel that works, I have made some measurements on the disassembled output transistors that work well:

B557 hfe 45 D427 hfe 51 * Are matched *
Vbe 573mv Vbe 570mv
Ic 6.1mA Ic 6.2mA

By equivalence I will use the MJ221193G pnp transistors and their complementary MJ21194G npn:

MJ21193G hfe 78 MJ21194G hfe 62
Vbe 556mv Vbe 554mv
Ic 6.2mA Ic 6.2 mA

The difference in hfe in this last couple is clear and my doubt is that if this difference in gain could cause any oscillation or malfunction.

Thanks in advance and greetings

I have come to accept that I will most likely not get around to completing this particular amplifier project. I have too many projects at the moment. So I'm letting these go to a better home. 🙂

1. PeeCeeBee V4H PCB Boards (6x available)
2. PeeCeeBee V4 PCB Boards (6x available)

Prices:

1. $30 shipped per pair (Continental US)
2. $18 shipped per pair (Continental US)

Photo:

Hi all

Thanks in advance if anyone can assist.
yesterday I started the process of upgrading PMC FB1 to FB!+ crossovers.
I desoldered 2 caps and 2 resistors and replaced with close tolerance items as specced by PMC.
I now have no HF output.
I've checked for tweeter function, good.
Checked for dry joints/breaks, nothing obvious.
Checked resistor values, good
Checked inductors, good, I think.
Removed and replaced back to stock, no change
Checked continuity up to and after caps, good.

Can anyone help with diagnostics on a crossover using a basic mm?

Its driving me nuts!!
I will try to get pics from the phone to attach later

View attachment FB1+.pdf

Sale:

Brand New (Never Touch) Purifi-Audio EVAL1 Amp = 5968DKK/each original price (x2)
Brand New (Never Touch) Hypex SMPS3KA400 Power Supply = 250Euros/each original price (x 1)

if sell in one-go, I would like to offer 5% more on the price

After 25% off
EVAL1 = 4476DKK = 715USD/each
SMPS3KA400 = 187.5Euros = 225USD/each

if sell in one-go, I would like to offer 5% more on the price
Sorry for the people who trying to send me PM, but my box was full...
Please fill free to PM

Anyone done this? I just completed a build and got some strange things going on - a bit distorted...cannot tell if its SMPS or something else...

Thinking of just putting in a pack of caps between the SMPS and amp or just going to conventional linear power supply...

But any reason why it would not work?

The new ESP forum is horrible (old, very good forum long gone and deleted)....

Can anyone tell me if there is a music player app that will do the following. Run on Android with support for Android Auto and allow playlists to be created and customised on a PC. Currently I use Black Player to listen to music in the car, usually via Android Auto. Loading new tracks from my PC onto the phone is no problem but there is no way to access and create or customise playlists on the PC. Doing this on the phone itself is fiddly and time consuming, especially if creating large playlists with one or two tracks taken from multiple albums. Sorting music files is much easier on PC with the large screen, keyboard and mouse. The ideal would be a player that runs on both Android and PC and allows content from the PC based app to be transferred to the phone. Does such a thing exist?

Hi.

I'm looking for FRD/ZMA data files for Tang Band W3-593SF, but PartsExpress
website did not have anything but an optimistic-looking graph from the vendor.
Tang Band W3-593SF 3" Full-Range Silver Cone Driver

Does anyone here have such a file(s), or know where I can find it? Unfortunately, I can't move forward on my project without this information.

Thanks!
-Charles

I've build 12AX7 preamp with 12AU7 cathode output while back that I'm not using and was wondering if it's possible to convert it to simple compressor or limiter using these tubes. I'm not finding any schematics at all so I thought I'd ask if it's even possible and if not, why? Thanks

Hi,

Its a c17 capacitor in Musical Fidelity A1, i beed to replace it.

Anyone know what type of capacitor it is ? And what is the spec?

Just bought an amp and I tested all the tubes discarded the bad ones and now have a full complement of tubes that test good. I know from the previous owner that they have a good number of hours on them but dont know exactly. They are quiet no noise. How do I know if sonically they are tired? The 6550 should be replaced after 3000 hrs and the tubes date codes are 2001. Not sure I want to drop $500 only to find out I dont need them.

Am I correct in assuming that this 18W/8545 driver is identical to 18W/8545-00, even though it doesn't say "-00"?

I was just over on the JBL Pro site looking for the T/S parameters and notice some of the white papers they have up on one of their cinema speakers the SR9350. These are new to me. Has anyone else seen them??

I find them to be very intriguing and maybe some potential for DIY based on them. Have a look!

Rob 🙂

9350 | JBL Professional Loudspeakers

Does anyone have any experience with these tubes? I just bought a handful for a decent price and had some time to play around with one doing some distortion measurements before I needed to recharge batteries. The measurements came out with 2nd harmonics roughly -45 db under fundamental and 3rd another 5 db behind that. That was pretty consistent through the small amount of points I tried. One thing that struck me was that the operating points don't line up with any of the current data available online especially at higher voltages. I originally planned to use this tube as a driver for a 6a3, but I am going to move on to other options and save them for shunt cascode experiments given their decent gm. Just curious if anyone has any experience.

Same as the title sais...I'm just offering tubes for high power germanium transistors same as in the title or similar..

New dac from Bruno Putzey

Gramophone Dreams #55: Mola Mola Tambaqui D/A processor | Stereophile.com

Cheers George

Sounds weird but I toying with the idea of putting a 2.1 plate amp into a passive sub cabinet But I want to keep the passive input. What do I need to do with a wiring? Is it as simple as a switch or do I need diodes?

Hello everyone,

I was reading on the forum until late last night about how I can punch a rectangular hole in a piece of sheet metal. To be specific, I'm talking about the sheet metal used in the Hifi2000/DIYAudioShop Pesante chassis. (My ultimate questions are highlighted below.)

I've had the electrical portion of my design project done since last year, and I set out on the task to finish the job, but Hifi2000 says they can't mill/drill/punch/etc. the steel they use in the Pesante rear, side, top, and bottom panels. I have a Schurter AC supply socket that I want to use, but it is bigger than the simple IEC panel cut-outs they offer. I also want to be able to hide the power switch that I selected on the bottom panel of the amp on the front right side.

From what I read here, the "best" solution is to find a Greenlee knockout punch. The knock-out that is closest in size to my power switch is $360. That is a very expensive hole. I also tried to find the q-max punch mentioned, but I was unsuccessful in finding one of an appropriate size. Does anyone have a link to their website? Searching for "qmax" in A LOT of results. I would need still a different size punch for the power cable connector.

Is there a type of professional shop that I can look for that might have these types of tools and could do this for me? I will also need drilling of round holes for I/O in the back panel and holes for mounting the feet in the bottom panel. What kind of shop would have a CNC that can mill 1 mm steel?

Jeff

I've built a Pass F5T and I'd like to wire up the two XLR female connectors incase I decide to use them in the future.

From what I've read about XLR, there's a bit of voodoo that takes place somewhere along the line (the difference of two wires get's thrown out) perhaps at the connectors?

I want to be sure I get the wiring correct for them, and didn't find much about wiring up the actual connectors vs new wires on youtube and the web.

I got a pair of Cardas CM F XLR
CM F XLR (Female XLR)

From the internal boards, I have a Left +, Left - and Right +, Right -.

thanks

For the last few days, the DIA AUDIO app requires me to log in again after every page renew that I initiate. This is a PITA. No other app on my ipad requires this.
Have I flipped a secret switch or what?

gate dri tranformer class d , tl494 mod for class d
it simple circuit i test +110v load 4 ohm fre-class d 75k-130k

????????????????half bridge to class d amplifly by foodland - YouTube

For Sale: Bel Canto EVO 200.2 amp with Tripath based TA105A amp unit.

Amp power supply caps have been replaced with ew and ready for another 25 years. Widely lauded as the one Solid State amp that sounds most like a tube amp due to the Tripath Class T design.

Asking $875 for EVO 200.2 Amp

Also have the matching SEP2 Tube preamp. Tube compliment is a pair of newer 6922 Tubes. Pre has aftermarket remote.

Asking $875 for SEP2 preamp

May be able to make a package deal for both. Not a scratch on either amp or preamp and both work perfectly.. .

Ships from West sub of Chicago or pickup...

Hello,

I'm looking to build something similar to the Linkwitz LXSub4 Dipole for use 50-400Hz (see image). I have 4x 15" drivers (Faital 15PR400) and each pairing would be driven by a MiniDSP 450W amplifier with DSP EQ/Crossover.

The plans are available to purchase, which is great, but the drawing is for 10" drivers, and I'm not wholly invested in the idea. I am looking for a quick proto to assess, before moving on to something more traditional if it doesnt work out.

If anyone can please advise: are precise dimensions required for this to work properly, and by extension, therefore also required for a 'scaled up' version?.

I did try to extrapolate from the internet drawing, and I am almost certain this drawing is not 100% accurate - no surprise as they require you to 'buy a license and then the plans'.

Hopefully someone has been here before with this design, or something similar, and can advise.

Thank you

Good afternoon. So I didn't get an e mail back from feastex about drivers and pricing? I am looking into the drivers for a project for a friend of mine.

1. Where can I buy the drivers at?
2. How much is each size and model?
3. What types of boxes can they go in?


Thanks for your help. Jeff