Hello everyone,

I'm looking for advice on most accurately modelling a 6th order enclosure. Currently I have a 6th order using two Alpine Type-R 12's but for the next season I've decided to go bigger and have chosen to employ two 18's and fitting them has introduced some unique geometrical constraints that I am not sure how to best approximate in Hornresp.

At a high level the object will be to play broadband 35Hz-100Hz at power levels ~1000W-3000W. I've decided to go with PA drivers this time because B&C 18SW115s came up at a steal of a price (~400CAD each, new). Additionally, they seem to best the the Type-Rs in all other categories; weight, power handling/compression, mid-band sensitivity, still have generous excursion capability.

As I've modelled and built 6th's well in the past I was hoping to model conventionally with the rear section firing forward (thus eliminating a mid chamber). Unfortunately after building the rear section it appears that am short 1" in terms of clearance to close the trunk, thus I have to lay the rear section flat and have the drivers firing downward which introduces some interesting considerations of having a mid-chamber (I guess turning this enclosure into technically an 8th order).

In nutshell, this system comprises of three sections in order to fit inside the trunk (will be sealed together using foam gaskets so they can be easily disassembled). The images I put together PPT below show the general configuration. The side-view I think most clearly shows the geometry of what I am dealing with.





(All values below are net after displacements, wood thickness is 0.75" MDF)
- Rear (yellow): ~104L: houses two B&C 18SW115s, two 22cm 4"ID PVCs, when considered standalone tunes to ~38Hz. The drivers are recessed in this chamber by 0.75" for speaker protection.
- Mid (blue): ~42L: a chamber with an open-top that serves a "pedestal" for which the rear chamber to fire into. In essence, the foot-print of this chamber is identical of the rear chamber that is mounted atop of it. The front of this chamber has an opening to where it mates to the front chamber; the opening here will be ~3"x29.5". This chamber is the crux of the problem as it has an effective axial area of ~895cm^2 (3.75"x37") over a length of 47cm which then steps into to front chamber having an aperture of 571cm^2 (3"*29.5").
- Front (red): ~136L: this chamber sleeves the inside portion of the trunk and mates up to the ski pass (~489cm^2 of port, ~2" in length but this can be adjusted as needed). From the top, the front chamber is slightly narrower than the rear/mid chambers.

Modeling is done in Hornresp, with 1kW of power, using semi-inductance parameters I've derived from the impedance curve. The volume of each section is quite trivial (~286L total in each model) but it seems that the geometry (in terms of length/areas) results in significant deviations from model to model. I would appreciate any advice on what would be most appropriate. The problem at hand is that I don't think I can bin the mid and front chambers and consider them simply in terms of volume as I think there are some compression effects happening in the mid-chamber.

Model 1: TH1 using a standard rear chamber, mid-chamber is approximated ~895cm^2 using two horn sections (this not account for the step change into a 29.5"*3" (571cm^2) aperture into the front chamber.


Model 2.1: TH1 using a standard rear chamber, mid-chamber is accounted for in Vtc/Atc; Atc is 4416cm^2 giving a length of 9.52cm, this loads into the front chamber through the 29.5"*3" aperture into the front chamber which is accounted for here


Model 2.2: TH1 using a standard rear chamber, mid-chamber is accounted for in Vtc/Atc; Atc is 895cm^2 giving a length of 47cm, this loads into the front chamber through the 29.5"*3" aperture into the front chamber which is accounted for here


There are a couple critical questions in regards to the models:
- Models 2.1 and 2.2 are quite similar with the difference being the consideration of the "length" of the chamber relative to everything else. Is it seen as 9.52cm (height) or 47cm long (length). I like these in that they both consider loading into the front chamber through the step change in the mid chamber but are quite different due to the considered length of the mid-chamber? What is most appropriate? Or maybe something in the middle, like a 24cm approximation of length.
- What is the most "correct" placement of the front and rear entry points? Effectively, I would like to have woofers and port as a single point loading in at 25cm (the center point of mid-chamber) but I don't think that it's possible to do with more segments, which I don't believe Hornresp supports. Given horn-resps constrains it seems that the driver and vents are offset by some distance which results in model differences between the two.

Model 3: BP8 Wizard where the mid-chamber step is considered as a 0.75" port of area 571cm^2. I think this one is the most ambiguous of what is happening in terms of geometry.




All in all, I think the responses in all models looks fairly workable in the frequency band I want to target but it would be nice to have a relatively flat response with slight emphasis at 40Hz (which model 2.1 presents).

As always, I would be very greatful for any advice and insights on this design.

Victor,

I would like to thank you for your encouragement and advice, both in making an informed purchase decision, and during the construction of my new TU-8600S amplifier.

I was pretty hesitant going in, but I jumped in with both feet and never looked back. The packaging of the kit was excellent. The manual was amazing. The only way anything could have gone wrong was if I failed to follow directions.

After much lead bending, soldering, trimming, checking & rechecking, etc. I had a fully populated PCB. After comparing the completed PCB to the floorplan, I assembled the amp without covers, installed the tubes, plugged it in, and flipped the switch... No smoke!!! So far, so good. I then check all of the voltages and they were all within spec.

The last test was to hook up a pair of speakers. Music!!!

Again, I cannot thank you enough.

I will attach photos as soon as I have everything buttoned up.

I am looking forward to my next Elekit project with VK Music.

Sincerely,

Lew

I got a LUXKIT/LUXMAN A501 scaned schematic in the net, Then I input and simulate it in TINA-TI .
If any one need these information, I had attach here and welcome to use it .

Hello Everybody,

I'm looking at a pair of Lii Audio F12 fullrangers. I did a search here for Lii Audio but nothing came up. Anybody have experience with Lii and can speak to build and audio quality? Apparently they have made some inroads into the Decware and SET communities.

Based on these specs for the F12, could anybody give me some box sizes with front port size and length? Unfortunately they don't list Bl, Mms or Mmd, Le, or Vas.

Nominal impedance Z: 8Ohm
Power：40-80W
Frequency response：50-15khz
Fs: 32.8 Hz
Sd: 53.093m³
Qms: 14.629
Qes: 0.746
Qts: 0.710
Magnet：Y35（Ferrite）
Mean Sound Pressure Level: 94.8dB （2.83V/1m）
Weight: 11 KG
Package dimension: 42*36*36 cm
Paper Cone Material: Compound Pulp


Thanks a bunch!

Q: I really like my buffered volume control (BVC) and it sounds great to me and the kind of music I enjoy listening to. So why am I planning to rebuild it?

A: Because it's there!

Not having any mountains to climb, at least for the present, I always wanted to say that. Now, to the specifics: My present set-up, which I use to listen to CD's and my FM tuner, consists of a dual 50K Alps pot driving one AD845 op amp per channel connected in non-inverting voltage follower mode. Very simple and basic but it seems to work very well.

First, I plan to replace the Alps pot with a 50K stepped attenuator. Probably 24-position unless a 47-position would be more useful?

Second and last, I want to build a remote power supply mounting the transformer and the rectifiers in a separate enclosure connected to the BVC enclosure with an umbilical cord thus removing all AC from the signal-carrying section. The separate power supply will house a 3-conductor line cord (grounded to the PS chassis), a SPST on-off switch, a fuse holder, an Avel-Lindberg 100VA, 18V transformer, 2 bridge rectifiers (one for each of the A-L two secondary circuits, with the diodes bridged by .01uF metallized polypropylene caps) and two 1000uF, 35V electrolytic caps at the output. The 1000uF caps will add to the 4700uF caps already in place on the PS board mounted next to the signal-carrying board in the BVC enclosure. The bridge rectifiers and bypass caps will be removed from the PS board as they will no longer be needed.

BTW, the PS board was designed by Grayson King and I populated it with all the components that he recommended so I'm sure it's of the highest quality. I obtained it from the days of Audio Amateur magazine when they use to sell a great variety of materials for the DIYer. I also have his board for the preamp he designed but have not used it because I only wanted a simple buffer whereas the King board provides gain. How I loved that magazine!

A couple of questions I can think of off the bat: I'm using a star ground system in my BVC enclosure where the power supply board is also grounded. Should I also ground the PS to the remote PS enclosure where the line cord is grounded or avoid that connection?

Finally, would it be worthwhile to employ a SS relay for turn-on or would it be unnecessary or overkill? I was thinking of the Crydom A1210 for example which turns on at zero crossing. Whether or not I use it will also determine the dimensions of the separate PS enclosure I will need and as I'm in the process of gathering the parts I need construction will take a little time.

Thanks to all who read this as while I enjoy building relatively simple audio projects admittedly I am a rank amateur in the field of audio. I would certainly appreciate any suggestions one might have.

PLEASE DELETE - Posted in wrong section.

Our annual clearance is now on, please visit our website for a bargain on a huge range of DIY cables, vinyl and sacd's

Please click this LINK to be taken to our website.

We are BREXIT READY.

I'm selling these wonderful speakers, even these are the best in my audio life. These where bought new from Earl in 2014, and I've used it for about two years.
I moved from the place (pictures at Earl's forum) I had taken pictures in 2014. In my new house, I' can't find a place where it sounds right, as the acoustic is terrible (even these speakers are good with small rooms). I've tried almost everything (and of course Earl's recipes). As I won't move in a near future ... and headhones are not bad at all.
As it costs something sending it, it could interest someone in Europe.
I can also sell together, but this is optional, all the stuff to make this Summa work:
- miniDSP 4x10 HD and / or NanoDigi 2x8
- two Rythmik subwoofers
- digital amplifiers (diy) and / or gainclones (diy)
- one Allo player with Digione
I'll send new pictures to the ones interested and answer the questions.
Alain

This module is marketed as super efficient (even at lower output powers) not requiring a heat sink for 100W output. Whats interesting for me is that the operating voltage is high (80V abs max) and the thermal resistance to the case isn't that high (4C/W). I'm thinking with a bit of heatsinking and a multilayer board with thermal vias for real world signal crest factors in excess of 6dB this amplifier could be bridged into 4 ohms loads and not overheat.

This is an app note where a small heatsink is applied and continuous ratings of 130W achieved and also peak power up to 220W with a heatsink:
https://www.infineon.com/dgdl/iraudamp12.pdf?fileId=5546d462533600a401535697359c2bdd

I guess what would stop this working would be if the chip started to limit output current and/or some other mechanism caused high distortion. The datasheet does have an over current protection block shown in the block diagram which is set to 16A limiting peak power to ~500W.

Seems to be a lot of advantages for the usual TI parts and I can't find any DIY discussion.

Anyway thoughts?

I ordered 1:1 Transformer from edcor for my pre amp. But it had 3 pins in and 3 pins out so I'm not sure which ones to use? Should I use the plus and minus or the plus and ground?

They were all the rage a few decades ago, and a few still sold, but I was wondering looking at the need to move to a 1 1/8 tweeter to get the crossover low enough for a 6 inch mid/bass, but top end issues and excessive stored energy make it a less than an optimal option. What are the drawbacks from the larger tweeter, and then slap something with a great top end, even a little XT-25G on it for 10K up? First order crossover even.

I would rather a really great midrange that could get up to 4K where you could use one of several decent 3/4 tweeters, but they seem to be in short supply or their efficiency is so low, you would have to bi-amp.

Working on a KX1200.1

Not in protect. Relay comes on. No audio.

Have found no shorted components. Do have a triangle wave on Pin 4 of U14, no square wave out of Pin 11

I read in the main NAJDA thread that it's possible to utilise both FIR and IIR filters in the same setup, using IIR crossovers on the outputs, then adding a FIR filter on the inputs to align the phase.
However, only the FIR filter setup allows you to load filters on the inputs. So how does one go about specifying IIR filters on the outputs in the FIR setup section? Is it simply a matter of loading IIR coefficients instead of FIR? Or is there something I'm missing?

I am looking for a pair of Alpair 10.2 drivers if anybody has them for sale.

Thanks,

George

I have a Quad CD67 that has been modded in 2010 by Fidele Audio. I am informed that Fidele Audio ar no longer trading and so my question is, does anyone know what mods this company offered for the Quad CD67?

Hi Victor,

Is this the proper orientation for the V Cap capacitors on the TU-8600S board?
View attachment 863260

You told me on the phone that red was negative and green was positive. Do I strip those red and green insulators only to the point where the legs fit through the holes on the board, or do I remove them completely?

Thanks,
Allan

HAPPY NEW YEAR!!!

I could use some advice please...

I have a pair of radian 475 PB-8 compression drivers in Altec 511B ( I think ) or 811B horns, atop a JBL AL6115. Not sure if this is a great match....

Radian says the lowest recommended x-over freq is 1.2 K, but fails to mention the slope.

Since this is for home use, so it will likely only ever see 1 watt or less of power... maybe 2 if I'm nuts.

Would the Radian 324/1594 be a decent crossover to use in this installation? ( 1.25KHz crossover frequency ).It is 12 db per octave.

Radian says: NEW 2-Way 1.25kHz Crossover

Phase, Frequency, Time Delay & Volume Compensation
For Use w/ A 8 Ohm High Frequency Driver & 8 Ohm Woofer
Time Aligned For Use w/ A 90°x 40° Horn <- this looks ok

Any help here would be most appreciated!

Hello all,

First off, I just want to warn that I am in school for mechanical engineering and have only taken enough electrical classes to get myself into trouble. That said, I am trying to design a 3-way active crossover to use for a stereo set of Econowave speakers I am building (I know, late to the party...) as well as a single subwoofer. I have a MiniDSP 2x4, and plan to use 2 of the outputs for the compression drivers exclusively. The other two channels will be the L/R output for both the mids and subwoofer content.

I am in the process of designing an op amp based circuit to further split the mid/low content between the woofers and sub, crossed at 100 Hz. Following the information on the Linkwitz site, I think I need 4 circuits per channel: a buffer, a high pass to the woofers, a low pass to the sub, and some sort of phase correction on one of the channels (absolute phase can be corrected in the DSP). I have implemented the first three circuits using a generic op amp in LTSpice, with the schematic as well as frequency and phase response attached.

Note that the high pass is an LR2 circuit, while the low pass is an LR4. I chose this because the woofer already exhibits a rolloff below 200 Hz, and I think using a 4th order high pass might result in too deep of a null in the crossover range.

It seems like the circuit is doing everything it should, however I have a few questions to finalize the design which I would appreciate some expert insight on.

1) There seems to be a 90* phase offset between the high and low pass. Does this seem right? If so, is there an all-pass circuit that I could use to correct a 90* phase offset? The Linkwitz web site only lays out circuits which result in a phase change of 180*. Or, would it be better to use an LR4 crossover for both circuits so that they have equal phase change, and then correct phase and any equalization issues with the DSP?

2) I designed this as an op amp circuit, particularly with the OPA2134 in mind, which seems to be a favorite on the board. However, I am in no way an expert on component choice and am not even married to the idea of using op amps. I have seen the JFET (?) topologies used in the Pass active x-over board and would be interested in that as well, but am less sure on what the schematic should look like. Does anyone have any input on using op amps vs discrete transistors, or component choice in general?

3) There will be a big difference in efficiency between the woofer and sub. I remember from an electrical class that op amps can be set to have a gain; would incorporating an additional gain circuit on the sub output be a good way to make up for this level difference? Or perhaps a simple class A pre-amp circuit?

Any insight on any of these questions would be most appreciated. Thank you!

I have an Amber series 70 with what seems to be defective LM391N-100 chips in both channels. I have 'Fluke meter' checked every diode, the drivers, and outputs and all test OK in circuit.
I am considering taking a chance on a 'off shore' source for the chip but would appreciate ideas on the best source. Also any other tests that could be performed before inserting the new chips?
The Amp powers up and fuses hold with driver boards installed and chips removed. One of the chips will smoke the two 68 ohm series resistors to pins 15 and 16. The other chip does not burn these resistors but send the speaker output to +38 VDC.

SOLD 46 TONG-SOL new tubes

SOLD SOLD I broke the seal on one of these myself. Tested on a Hickok TV7-U
50 is low . black plates , hanging filaments , nice boxes , made in the 30's
Tube test 102 and 97 . New tubes would make a nice amp.
80$ per pair

Hello -
I have an NAD 4020 tuner and the display light has gone out. Would anyone happen to know what value the bulb is and if it's still available (source for replacement)?

Anyone replace with LED? As the current bulb appears to be to one side of the display I'm wondering if it would still light the full display as the bulb does today. (I'm assuming the LED has less lit surface area to shine on the display.)

Thanks,
Comsat

I am looking to buy 20W Class A amplifier based on project published on Silicon Chip magazine and later in Everyday Practical Electronics in 2008.

If anybody has a unit made and no longer needs its or uses it.

Thanks

FS: Paradise Pre Regulator includes PCB components including transformer/rectifier/Chokes - Please contact me if you are interested. I have my original paypal mail with actual cost cost to me + shipping+Paypal
first come first serve- please PM me. Prefer US buyer as it is heavy and shipping will be reasonable for US buyer
thanks
kannan

One pair of Super Regulator boards. The circuit is as published on Jan Didden's website. I opted to place both positive and negative regulators on the same board with a common ground, connected at the input. The sense inputs are hard-wired and not brought out to external pads. Voltage is set for 17.7V but, of course, can be changed easily with a single resistor swap.

Dimensions are 2 3/4" x 3".

These are prototypes I built in November using all new parts. They are in perfect shape and are very lightly used. The only issue is a layout error on the LM329 references; to fix, I had to cut unused pin 1 off the TO-92 devices and mount on the remaining two leads, which should not impact function or reliability.

I've built more of these (with corrected layout) and they've worked first time and show no signs of instability.

I am also offering two unpopulated PC boards (also corrected) for a complete dual-mono power supply.

My actual parts cost for the individual regulators is $50, which is my asking price. I'm asking $10 each for the bare boards. Buyer pays shipping.

Please note: I guarantee the regulators will be in working condition on shipment. For the bare boards, I will provide technical support within reason; but the buyer should have experience with high-gain circuits and SMD soldering. Please do not bother Mr. Didden with issues related to my layout. Out of respect for the original designers, I will not be releasing the design files.

Hey everyone, this community is awesome. I'm learning a ton reading through the forums. One thing I haven't come across yet, is how to handle soldering two "output" wires to one binding post terminal. I've scoured the web, looking for videos or walkthroughs documenting how to handle the situation, but haven't found anything and am admittedly clueless. I'm attempting my first ever soldering with my first ever amp build on the 500ASP, with ghentaudio GK-ASP-MX case kit. I have one xlr input and a single pair of binding post outputs. The wiring harness that comes with the GK-ASP-MX has a jst signal cable with two red wires and two black wires. I'm assuming that I just solder both black wires to the black terminal and both red wires to the red terminal, but I don't want to fry my board or my house 🙂 If this is the method, what's the benefit of two wires per terminal (I see most builds online to only have one per terminal)? Is this required for "balanced" output? It seems that if you munge it all together in the same terminal, you're providing the same thing as one, maybe fatter wire, but I'm sure I'm missing something.

Thank you!

Robbie

Hi everyone .
i am looking for a single coil bistable signal relay.
(not to be confused with step-by-step or magnetic relays. They are completely different relays). I may also need dual coil ones.
I need to build a volume attenuator, I would like to choose the one with the best value for money.
do you recommend me please?

Hi,

I offer bare PCBs for a bipolar PSU based on the TPS7A4901/TPS7A3001 low noise LDO regulators. It is capable of up to +150mA/-200mA current supply at +33/-33 VDC. The absolute maximum supply voltage to the board is 25 VAC (each rail) or +36/-36 VDC. The board size is 3x8 cm, mounting holes are on the 10 mm grid (2x7cm center-to-center distance). The design is briefly documented here. The schematic and images of the bare and assembled boards are attached.

PCB is hand solderable. The only challenge is soldering the thermal pads of the regulator ICs. It requires strong soldering iron to conduct the heat through the vias from the underside to the thermal pads. Using hot air rework station significantly simplifies the assembly.

The estimated BOM at Mouser is around 38 Euro.

I also offer a new design board using DC-DC converter at the input (see post #10 for details and #11 for the BOM). The development thread is here. This board size is 3x7cm.

Price: 6 Euro/PCB (bare board, no parts)
Bipolar power splitter PCB: 2 Euro/PCB

Worldwide shipment: 2 Euro (ordinary mail) or 4 Euro (registered mail, traceable).
Payment by paypal.
PM if interested!

Regards,
Oleg

I have owned two Martin Logan Ascent speakers for a number of years, and have recently noticed that the two electrostatic panels have slid down in their supports, in one case severing the three connecting wires, blue black and red. It is clear that the blue wire has to be soldered to the front of the panel, and the black wire to the back of the panel. I can't see how to reattach the red wire. Ih has a small strip of copper tape attached to it (see attached photo). It may be that the copper tape goes all the way around the edges of the panel, in which case it may be impossible to reattach the wire. I live in Belgium where there is no Martin Logan dealer, so any advice you can give me would be most appreciated.

Why should the guitarists be the only one recognized? Let's hear about your favorite drummer, drum solo, or outstanding drum recordings...

Favorite solo: Dave Weckl and Steve Gadd- title track to Weckl's cd "Master Plan". Both drummers playing on one track, alternating solos, panned slightly left and right. Not the best recording- completely overproduced, as are most of Dave's recordings, but great playing.


Anything by Vinnie Colaiuta...

NS

I am coming up with a large ported home theater subwoofer enclosure design. The goal is a low tune with minimal port noise. But with a port that is large enough to keep port air velocity low, I am now getting a calculated first port resonance of 87Hz in WinISD.

I can of course get it over 100Hz if i make the port slightly undersized or make the internal chamber oversized. But is a 100Hz port resonance still a big problem?
How much do i have to worry about port resonance?

I hope this is the right place to post, I'm an amateur woodworker but no experience of diy audio. I ordered 4 of the Dayton Audio BR-1 component kits and the components for a TriTrix MTM to act as a centre. I'll probably build a par of subs next year. I also plan to make stands for all the bookshelf speakers.

Progress will be slow as I am also renovating the room to be used as a home cinema, but I thought there might be some interest in the speaker build progress here.

Last night I managed to assemble three pairs of the crossovers. My soldering was acceptable after I found my iron that has been gathering dust for years. The hot glue work was messy but effective I think, as everything feels nice and secure.

I hope this doesn't offend the admins, and will be taken in the spirit of a new year:

May the road rise up to meet you.
May the wind be always at your back.
May the sun shine warm upon your face;
the rains fall soft upon your fields and until we meet again,
may God hold you in the palm of His hand.



I wish every one a Happy New Year and let's leave 2020 behind us.

I got one but I managed to break the 5v supply to the IR/remote circuits which with a f/w update has rendered the player useless. It would operate through network controls but with the update it will only "listen" to the remote control as part of finalizing the install.
I had 12 volt on the 5v supply so I am assuming the remote IC and support is fried.

Does anyone have an understanding of the circuits in these units and what IC I would need to change?

Hello everyone,
I had the "opportunity" to get 24 Telefunken tubes, model E88CC. I'm pretty confident they are genuine, for reasons I won't mention here. I have a uTracer and tested all the tubes. I made two tests :

• quick check, where I set heater at 6.3V, Ua = 90V, Ug = -1.3V, and verified the Ia, which should be a typical 15mA.
• the curve tracing, where I'm able to measure the current in the two triodes at the same time, in function of Va and Vg. In fact the same as above but for multiple points.

So I measured all 24 tubes (left 3-5 minutes for heater to settle before taking measures).
From what I read, is that I should get the typical Ia around 15mA at its minimum, mostly between 100 and 110%. However, most tubes are in the range 70-85% for Ia.

Below an example for one E88CC, and I would like you to comment it. The question is, are all these tubes good for the waste recycling ? Or do I oversee something and I'm sitting on a "small fortune" ?

hi global people, I need your help, could you send me a copy of instruction manual for ampli Luxman LV-105? My adress is v.frigati@virgilio.it
Thanks in advance for your interest

"SB acoustics sb34nrx75-16" new driver designed specifically for open baffles?

A few hours after sending questions on this forum about fullrange speaker candidates suitable for open baffle systems, and very pleased with Dave's reply,

I found another open baffle candidate on the website of a professional speaker manufacturer who had long known in foreign countries.

SB Acoustics is a subsidiary of "SINAR BAJA ELECTRIC Indonesia" together with Danish, a Danish citizen, reportedly is the best former designer in Scan Speak. he is Frank Nielsen, I don't know him, I don't know much.

Recently they have included a list of new drivers claimed to have been designed specifically for the open baffle system on their website ,.

My question is; is there anyone on this forum who uses and opens an open baffle with this driver? Is this driver eligible to be filled in a shopping list or not? I hope to get a pleasant answer from this forum ,. 🙂 Thank you..

SB Acoustics :: 12” SB34NRX75-16

Hi - I was just wondering if anyone had produced a compact PP amp using two tubes. That is a single double-triode to perform pre-amp and phase split and a double power pentode (such as 6DZ7) as a PP driver?

If so, I guess quite a compact stereo PP could be made with just 4 tubes assuming SS rectification.

They say curiosity killed the cat, but I don't have a cat so it's worth the risk...

Good morning,

I'm building my own line array speakers. I plan to purchase two 10" 250W speakers for it. Do you think that running 2xTDA7294 bridged can supply enough one of these speakers?

I'm afraid to run the speaker with too much power, as I already had a single TDA7294 amplifier and found it very powerful for a single 10" speaker (never had courage to run at 100% volume) in a home listening context.

But when running it as line array in a PA system context, I don't know if 2xTDA7294 will provide enough power to cover 200-300 peoples room (planning to use 4 speakers cabinets * 2x10" 250w speakers per cabinet = 8x10" speakers with 16xTDA7294).

As this will be used with subwoofer cabinet, I would says that these line array speakers will get lowcut processing, eliminating some low frequencies power. Maybe it will become less risky to provide high power to the speaker?

If you have any other IC proposition for my project, tell me, I'm very interested.

Thanks in advance.

So Im looking to reduce the gain of my tseii thats running 300b tubes. The amp sounds geat and super quiet if Im running it without my preamp but requires me to turn the source volumes down significantly. Once I add the preamp into the system, I am getting quite a bit of noise since my tse is running at full gain without a pot. Im not really looking to cut more holes in my chassis and dont have much of a need for an adjustable pot on the amp. Im hoping to be able to install a few resistors in the incoming signal to reduce the overall noise of my system when running my preamp. I know i need to create some sort of volage divider with resistors but the actual implementation and values is beyond my knowledge level at the point. Thanks in advance for any help!

Bryce

Hi,

Finally posted some instructions for my project on instructables:
USB Audio DAC

Finished it years back, so maybe it would be the time to check if there are any new chips that are plug and play and higher performance without high license costs.

Works great for removing USB noise and mains hum (measured) and sounds great to ear, someone said the low end might be too high, but no calibrated measurements done.

Hi. I recently acquired a Philips CD620 which surprisingly, works perfectly except the phone output volume is very high to the point of being uncomfortable to listen to. I have looked inside and cannot see any signs of modifications; all appears to be stock standard. I will modify to lower the phone output but would like to know whether or not this is normal for a CD620.

I have a wonderful pair of bass bins and want to combine them with a pair a horn loaded speakers. Two or three way is still fine. I am looking for horn speakers that sound amazing on high quality music. I'm wanting to get as close to 100db efficiency as possible. But anything over 95 is probably okay. I am looking for that very dynamic live you are there sound, without the hiss and shouty sound some horn systems bring. I have tons of speaker building experience. So I can build from a kit or from just plans. Thank you for any help you can give me. Have a Merry Christmas everyone!

Hello!
I've just bought the Volt+d, and will be using it with my B&O RL60.2(so far so good).


I'm not the biggest fan of the translucent case it comes in, and would rather make a nice wooden/brass box to fit it inside. I'm also considering making an on/off switch, and put in a nice toroidal ring transformer I have salvaged from some quality gear, which both have a 12v and 24v output.


My question is, could I connect the transformer right to the amp, or should I put anything in between ?


Would a toroidal transformer be better or worse than a laptop power supply?


Should I shield the amp from the transformer ?


And finally, how would I know which settings I should use for the AM bandwidth avoidance circuit..

Just thinking about the rationale of why one wd squeeze a driver with a big magnet into the tightest space possible. The backwave of a driver does not go straight back w a great big magnet and spider in the way. Often with modern designs the backwave also has to contend with 3 side panels at close proximity. Surely this affects mid performance

I know narrow baffle designs are supposed to image better or is that another myth?

https://www.nvhrbiblio.nl/biblio/boek/205-Babani-1st-Book-Of-Hi-Fi-Loudspeaker-Enclosures.pdf

a geezer's "comfort blanket"

(includes some reflector, Norman Fulmer's V slot box)

These are nice tweeters . specks are in pictures.
my PayPal is [ dustychi1@gmail.com ]
80$ and 20$ shipping in the USA
thanks Rick

I am building my amp into a new chassis. ( long story)..
And I am seperating the power supply from the gain stage. What is a good connector system and cable to use? I will have a 400V B+ wire and a 190V wire that goes to the driver. Can I run these in a 2 conductor cable without the cross talk degrading the signal? recommendations? connectors and wire/cable type opinions welcome. I also would prefer to not choose a connector that requires me to buy a $200 crimp tool.
I also assume I want ONE large and well connected ground between the 2 chassis. I have 2 regulator boards for the 300B heaters. I am going to put those in the portion with the tubes so any noise picked up will hopefully be cleaned up by the regulator. I also have a pair of AC heater wires but am going to put them in their own cable separate from the rest.

All together I will have:
1) 400VDC x 2 ( 1 per channel)
2) 190VDC x 2 ( 1 per channel)
3) 6.9VDC and Return x 2
4) 6.3 VAC x 2
5) Ground

Any advice is welcome.

Jeff

I'm building four amplifier channels and am needing the usual parts, I've checked Mouser, Digikey and Newark and I'm wondering if anyone has a go to vendor with decent prices I may have overlooked?

Thanks for any replies.

When I power the amp up and feed it 100Hz sinewave with no output fets the signal on the pads is a 100Hz 5v ac switching wave. Shouldnt it be much larger? The rail voltage is +/- 179vdc.

I'm thinking of building a Rod Elliott Lateral MOSFET Power Amplifier and in the power supply section of the article he specs. the transformers that are usable as:

"AC Volts DC Volts VA Power (8Ω)
20-0-20 ±28V 100 40 Probably too low for most applications,
25-0-25 ±35V 100 50 Fine for use in a biamped hi-fi system
30-0-30 ±42V 160 80 Maximum voltage for low power version
40-0-40 ±56V 200 150 Recommended supply voltage for high power
50-0-50 ±70V 300 240 Absolute maximum. Can be used, but not recommended - aim for a lower voltage if possible"

I have a 30-0-30 300VA transformer that I would like to use so it is almost double the VA that Rod specifies, any chance that someone would please let me know if this is usable?


Project 101 - High Fidelity Lateral MOSFET power amplifier


Thanks.

Looking for $390 shipped and insured in the USA. Great condition kept in a smoke free environment. PM for pics/questions

I were checking continuity of a headphone cable looking for shorts between pins and in a crazy moment I had the “amazing” idea of checking continuity looking for shorts with the cable connected to the headphones. It was a very brief testing and I began to hear some popping noises and suddenly I understood I was sending DC to the headphones coils. The headphones are very expensive ones (HD800S 300ohm). I tried them after and they seems ok but I’m very worried if I had damaged the drivers or affected to their performance or characteristics in some not so evident way (they are carefully matched drivers).
Any comments will be very welcomed!

SOLD SOLD Values are in pictures .
My PayPal [ dustychi1@gmail.com ]
50$ and 8$ shipping
thanks Rick

Vary nice caps . on par with Mondorf silver and oil.
JUPITER HT 1uf pair .
60$ and 6$ shipping
Pay pal [ dustychi1@gmail.com ]
thanks Rick

Hi,
I am assembling the new TU-8600s with Takman upgrade. The resistors came with a single 330 Kohm resistor taped to the front. What is it for?

First time posting...need help
I recently acquired the preamp. Very sweet sound, paired with the Adcom GFA535.
All inputs work fine, but turntables only play the left channel.
What I have done so far: with an oscilloscope, I checked the signal path all the way to the COM outputs of the IC531 (it should give me an amplified signal on 13th contact of the IC, but it doesn't. The opamp IC502 is fine, it spits the amplified signal of the phono on the 6th contact and I can still see the signal in the 18th contact of the IC531. The CD and Tapes/Video work fine. Only the output of the right channel of the IC531, when playing the phono, is dead.
My question is: is it possible that the IC531 (TC9152P) is faulty only in that input (18th contact)?
There is also another issue but I think they are totally unrelated: the tuner signal indicator bars shows good signal on local radio stations, but the sound is horrible. All radio stations sound pretty crappy. I have a 300ohm T antenna connected to it and all my other receivers work fine with it.

Anyone?

Thanks in advance

When you place a subwoofer in a corner you get more spl.

So what defines that corner?

A concrete floor does the job, but what about walls? 2x4 framing and 1/2 inch drywall seems to work. A bed sheet hanging from the ceiling wouldn't work. At some point in between is where the surface begins to act as a boundary.

Hello,

So this was (still is) my first speaker project.
I'm using 2 woofers connected in parallel both in a seperate vented box.
It uses a 3th order crossover.

At the moment everything is still as-designed, but now it's time for some fine-tuning. They sound ok, but there's a lot of room for improvement.

Now, I'm thinking of doing the following:
- Splitting up the Zobel network
So far there's 1 zobel network per cabinet, calculated for the woofers being parallel. I'll split this up so that each woofer has it's seperate Zobel.
- Baffle Step Correction
The frequency response is suffering from some baffle step (I guess so).
Will probably start with a baffle step correction for 3 or 4 dB attenuation, I'll see from there...

I'm still not sure if I can simply calculate the baffle step correction with just the Re devided by 2 and the width of the baffle by the actual width of it.
Since it's a bit more complicated because the 2 woofers are connected parrallel.

Please share your thoughts with me 😀




Regards and happy holidays

I killed a channel in my Sure Wondom AA-AB32971 T amp when testing it for current draw. I think one of the load resistor -ve leads touched the other channel's +ve lead... 🙁


I'm game to attempt to repair this (I know it's a $35 amp) and I have someone who can solder SMD stuff if required.


I'll need some hand-holding as I know zero about Class D.


Sure Electronics AA-AB32971 2x100W Class D Audio Amplifier Board (T-Amp Technology)

Hi all,

I have vintage LSK-300 Kenwood stereo speakers.
The 60mm tweeter has been damaged while cleaning (!).

Please help me by providing the information for replacement:
1. frequency range
2. Mechanical - dimensions (it has square type frame)
3. impedence (8ohm?)

Thanks in advance.

Hello.
I have a pair of nice midwoofers SEAS Prestige ER18RNX (H1456-08 Reed paper cone drivers) getting dust on the shelf waiting for a new project, but right now I will stop building, so I put for sale.
They have been used (60 to 80 hours), and measured but in perfect working condition and good shape.

I'm asking 70€ + PP fees + Shipping for the pair

So I took this clock radio apart to see what makes it tick and noticed that there's a ferrite bead in series with the 3.5mm input jack ground and amplifier circuit ground.

Does anyone know why they did that and has anyone here tried it on their own designs? I've seen this done on the signal lines before but never between the grounds on an input jack.

The first picture is of the circuit board itself, ferrite bead marked in red whilst the second image is a schematic drawing to clear any confusion.

Thanks. 😎

What's the best Q factor for RLC PSU? I read 1/2 = 0.5 = Q critical damped or have I to look for low quality factor (Q < ​1⁄2) is said to be overdamped or high quality factor (Q > ​1⁄2) is said to be underdamped?

If I understood correctly first I have to look for a resonant frequency out of our range of hearing?

TIA

I sell my stuff, as i need space for new gear 🙂

# pair of Fostex FE168e∑ in original enclosure and original Fostex diffusors, WBT terminals, Sommer cable internal

# Integrated amp "Musical Fidelity A1-x Class A" , Capacitors etc last year upgraded

# CD player PS1 + RCA interconnect cable

# Speaker cable Sonoran Signature 2 x 3m

System is in good condition, both optical and electrical ( just Vol Pot makes a little noise when turning )

Price for all stuff above 800,- EUR

I am located in Germany, NRW

Hi I have a Wem copicat ic300 and its has 4 741 in it ,all the same .
They are SFC 2741dc 7821.
There are many different types and wonder which would be the best replacements?

Thanks

Hello I have a eico stereo 40 that has a very tarnished selector switch. I tried caig deoxit and it's not removing the black tarnish what else could be used maybe Brasso?

I have a couple of dynaco mk4 mono blocks. One blows the 2A fuse when I switch it off for 5 to 10 seconds and then switch it on again. It has a JJ brand EL34, the other has some old stock type. This seems to be happening when the tube is still hot, but B+ has sagged significantly during the power down, causing a large in rush to the PS input capacitor (good and correct value). When this occurs there is arcing within the EL34.

Is this a problem with JJ EL34, or a problem with doing what I should not. This happened with a second JJ tube also. Have others had this issue?

I have been testing my stochino amp that I built and never finished many years until recently when it was first published, and so far have destroyed a IRF9640 and a IRF640 mosfet transistor. I have been testing it using square and sine waves up 100khz the specs say the -3db power point is 120khz so it shouldnt have any problem with this. I was only drawing about 2.1 amps from recomended power supply and driving a 4.7ohm resistor load. The amp should deliver 120 watts into 8 ohms and probably more into 4.7ohms So there was plenty of capacity left. I was Luckily the mosfets did not destroy any of the eariler stages when they failed but its still annoying. The mosfets were faily well matched. Maybe I had a poor batch or that these are just poor and ill suited for this application. Has anyone had any similar experiences.

Steevo

I have built Giovanni Stochino's ultra fast amp as published in Electronics World and I am very impressed with its performance. My previous ss amp was mid-80s design from Sydney Uni which featured nested differentiating feedback loops. Again, I liked this amp. What do others think of this Stochino's design vs other ss amp designs?

So I've been asked to repair a very nice vintage Marantz CD-73, fantastic piece of antique Hi-Fi, in very good optical condition.
I had a hard time disassembling, even though I got SM (for the Marantz it has only schematics, but I've got the manual of the Philips CD303), to get to CDM, but eventually managed and have already put fresh caps for the (in)famous blue axial Philips caps on laser preamp board and tested: no change, not reading.

All supply voltages measure ok. Haven't changed any other caps, though.

This is what the player does: all lights normal, drawer works, disc is loaded, starts to spin, making noises (don't seem bad) from laser, trying to read toc, then fails and makes a whining sound that goes progressively lower in pitch (around 2 sec), while disc starts spinning slower, then gives up, after 1 sec makes a new attempt which goes the same, then quits attempts. Tried several discs - no change.

Without disc, focussing can be observed and laser red dot is well visible with mobile phone, lens doesn't seem dirty.
Measured current delivered to laser (over laser driver transistor emitter resistor) and it seems fine - gives me 66 mA (1,03V over resistor).

Have checked laser preamp board for bad solder joints, all fine, or components looking bad, nothing, also measured all transistors and caps (as I only changed the electrolytics), all measure fine.

Checked voltages against SM - almost perfect, except one of them, IC6114A has -5,2V at pin 4, while in SM supposedly it should have -7. Btw, this is LM358 as opposed to NE532 in SM).
Outputs of IC6101 (photodiode array preamp) all show a little negative offset (-0,08V instead of 0V mentioned in SM), but I guess that can be normal?

Now comes the thing: while verifying adjustments, I noticed that I can't measure voltage for laser current control as described in SM: I probe at resistor 3308 as described, and it always is around 20mV, no change when laser goes on!! 😱

So, I started measuring voltages at servo board (which unfortunately I haven't disassembled yet, this player is hard to service, you need a lot of space), I'm measuring from solder side. And here I get odd values:

1) At IC6214 (LM324) output pin 1, SM says -7,1V when STOP, +1 V when playing.
It measures around -0,5V, no matter if I hit "PLAY", there's no change.

2) At IC6215 (LM324) output pin 14, SM says: -11,4V when STOP and -0,3V when PLAY.
It measures -3V when STOP and gets -4V when I hit Play, while it is briefly trying to read.

Also, at output pin 7 of IC6214, the voltage doesn't change between STOP and trying to read, stays at 0,5V.

Now, something even more odd: I thought, maybe the LM324 are "toast", because the solder of their pins seems different from the rest of the board, seems someone did a repair here before, so I DISCONNECTED the radial/focus error connector from laser preamp board and measured the same places:

1) gets -8V
2) gets -11V

Which are pretty close to values from SM... obviously I didn't try to hit PLAY 🙂

What can be going on here?? If radial error output is taken from photodiode preamp (which I can measure around -0,07V at each output), it combines two outputs with resistors, how can that signal cause the voltage to sink at both outputs of two different LM324? I haven't scope this, only DMM, maybe some oscillation?

Any hints here, please? Can this be normal, might I be chasing a ghost, I mean, maybe wrong indications in SM, and all the drive might need is turntable height correction? or some other adjustment (other than laser, which appears fine)? or mechanical problems, like swing arm not moving well enough (it seems free, but not perfect, sometimes seems to "stay" at one of the extremes. I don't want to mess around with the CDM, which I understand is much more complex than the later ones (which I know pretty well to service), if not needed, if this is a electronic problem.

Might this indicate some weird electronic problem, probably in laser preamp board? Or the LM324's on servo board? Would it be able to "test" them, simulating some kind of radial error input? or even just normal test signals? I'm kind of against just swapping some IC "because of a suspect voltage". Also, I can't do complete recap to servo board before knowing if I can fix the player, as this is paid task (but only if I succeed lol...).

Thanks for any hints in advance!

I have used my elCheapo Tube curve tracer data to write a small program that will analyse tubes and suggest matched pairs. See the attached screen grabs.

The GUI shows 16 6CA7 tubes test result files with a corresponding tube no 1-16. By clicking on the Match button at the bottom the results are shown in colour according to the colour code:

Yellow shows tubes that match within some limit (set by the slider) based on the sum of the squares of the difference between the anode currents across the whole of the test range;
Blue shows tubes that match within some limit (set by the slider) based on the sum of the squares of the difference between the transconductance across the whole of the test range;
Green shows where both of the above conditions are met;
Red shows suggested pairs (based on a simple algorithm of selecting first the tubes that have the least number matching criteria then continuing with what is left over etc)

I own a Michell Gyro turntable/Helius Orion/DL-103R connected to an ARC SP8 preamp through a John Curl Ro-3 Mc Kinnie pre-preamplifier.

Although my cartridge is providing a low output (0.29mv) I really need to reduce the total gain.

My John Curl pre-preamplifier is a second hand unit and I don't have the owner manual to modify the Gain with the internal 2-WAY DIP-switch provided.

I really would appreciate it very much if I could receive some advise on that.

Regards.

Antoni

For sale: Baby Huey EL34 PCB Partially stuffed

How's $65 shipped CONUS?

It takes around 3 minutes for relays to click in. Before clicking the relays make a lot of vibrating noise for 20 seconds or so.
There are two relays in there, one at the front and one behind the power supply capacitors. The noise is coming more from front relay as compared to the rear one.

I have also noticed that once the relays have clicked from "cold start", switching amplifier on and off with in one minute or so, they work as intended.

Once clicked the amplifier plays absolutely fine. I have

1- Cleaned all the pots and switches with servisol.
2- Replaced total of 4 caps which were showing high ESR
3- Checked for Bias and set it to 20mv
4- Checked for DC at output throughout the 3 minutes process and it is less than 7mv on each channel as measured between ground and centre leg of 0.33ohm resistor/one leg of coil.

Omron G5R-2282C-PA (Front Relay)
Omron G5R-2284P-PB (Rear Relay)

Can someone please help me with this problem?

Pioneer A-400 Stereo Integrated Amplifier Manual | HiFi Engine

Many Thanks in advance

Hello.
I have for sale a pair of NEW, in box, never used not measured SBAcoustics Satori MW13P-8.
They were going to be used in a project that I have cancelled.

Cheapest Retail price is 125€ each.
I'm selling the pair for 150€ + pp fees + shipping (18€ to most EU countries)

Hello.
I have a pair of Scan Speak 22W/4534G00 that were going to be used in a new project... but they were getting dust for long time on the shelf and I need to stop building, so, I put for sale.
They have been used (around 70 hours), and measured but in perfect working condition and good shape.

I'm asking 70€ + PP fees + Shipping for the pair

Hi;
I just found a brand new TDA7560 in my parts box and I’m trying to decide what to do with it. It was sitting there close to 15 years.
I was wondering if it’s possible to bridge it from 4 to 2 channels stereo – OUT1+OUT2 to one channel and OUT3+OUT4 to second channel.
I couldn’t find the answer in datasheet or on the net so I’m asking here if someone knows how to do it.
To be honest; I found one guy on Youtube who did it but I’m not sure if this is bridge connection. He wired one loudspeaker to OUT1- and OUT2+ and the second loudspeaker to OUT3- and OUT4+.
Here is the link (check time 5:17):
TDA7560 Quad Amplifier Deep Bass - YouTube

I’m looking to purchase working proton amps, specifically aa-1150 or d1200. Please hit me up with asking price. Thx

What's this called and how can I find a replacement. Note the missing leg that's why I have to replace it, the bottom pins are thinner than the top ones. I prefer Farnell. Many thanks. Ruler is in cm/mm and I know I placed it wrong but you might figure the distance between the pins anyway.