Selling a minty boxed NAD C446 media tuner. $175. List was $800.

It will play AM/FM//internet radio and has analogue and digital outputs. See NAD’s web site for additional info.

All factory included accessories are included: Remote, AM and FM antennae, power cord, etc. See photos.

Please PM me if you have any questions. Additional photos available upon request.

im based in the US. Paypal fees and shipping are the buyer’s responsibility.

Hi fellow diy-ers.

Update(19March2016): A couple new, improved and tested PeeCeeBee layouts have been uploaded. Links below.
Update(30December2016): PeeCeeBee V3 layout has been uploaded. The smallest yet the best sounding PeeCeeBee with 2"x2" footprint! Link below.

V1.1

Layout: >Here<

Pics:



V2

Layout: >Here<

Pics:



V3

Layout: >Here<

Pics:



(Old text from here)

Here is the VSSA all through-hole PCB as promised. (update- we now have our first SMD PeeCeeBee! Check at the end of this post)

Dimensions: 2" x 2.7".

There is no compensation capacitors and zobel on-board. If found to be necessary then the Zobel may be connected off-board at the binding post solder joints, and the Cdom(s) under the board between B and C of the VAS trannies. These accessories may find their place in the next version of the board, can't say for sure 😉.

The resistors marked OFF1 and OFF2 are to be left for fine tuning of the offset. A value of between 100K and 1M at any of these will set the offset very close to zero. These should be connected after the board is fully assembled with all the other parts. Ideally any one of the two resistors will be needed. If connecting on the positive side seems to increase the offset then leave that and concentrate on the negative side only.

The amp can be run from +/-15V upto +/-35V. The only part that needs to be varied is the default 15K resistors which are for 35V operation. I Use 10K for my 16V setup. This value is best decided through direct measuring of the VAS current at the 10ohm degenerators at their emitters. 10mA is a good bias, with small "U" shaped heatsinks for the VAS. Increase to 20mA if you can keep them cold by using better heatsinks. The trannies are aligned so that a single metal piece can be used for both. Don't forget mica insulator if this is your choice.

Pix of my finished and assembled boards:





If you have any queries about the board and setup etc. then feel free to post it here. I'll help as much as I can.

Happy listening.
shaan

edit:- The layout is in the VSSAbottom.pdf file.


Important:- Visitors/posters are welcome to modify any of the layouts according to their need and/or add totally new designs. However, if you want to use CCS or Multilayer Layout or Parallel capacitors in the feedback network then please post your VSSA experiment and results in the original VSSA thread. Link >Here<. This thread's topic is single layer printed circuit board designs based on the VSSA schematic without the above mentioned accessories, shown in one of the pictures attached below. Thanks for your co-operation.


Update(19/11/2014):

More Tested PeeCeeBee designs(kind contribution by fellow diy-ers):

1. By PMI:- Click >Here< (Pro-style layout with under-board MOSFET mount).



2. By Jason:- Click >Here< (TO3 output MOSFETs)



3. By dobrivoje:- Click >Here< (large onboard input film capacitor)



4. By John:- Click >Here< (old-school hand-drawn layout with curves)



5. By Damanhuri:- Click >Here< (Spacious layout with a lot of on-board PS decoupling)



6. By Olafk:- Click >Here< (Lovely Looking SMD PeeCeeBee)




Update(6/2/2013):

Some o'scope shots of PeeCeeBee performance:

1. By PMI:- Click >Here<

2. By nicos:- Click >Here<

3. By thimios:- Click >Here<

🙂

Introduction:
For years I've owned a Logitech X-503 multimedia system that provides the sound for my main PC. At the time I purchased it, it was around US$70, which was quite a good price, considering that the system consisted of 10" small 1.7" drivers (two in each of the satellites) and a 4" driver in a gnat-sized vented box to provide bass duties. The satellites aren't too bad (nothing that can't be fixed with a bit of EQ), but the bass unit was definitely a study in compromises. The driver has a relatively high Q and the box is tuned to around 80 Hz, so the end result is a big peak around that frequency that makes everything sound "robust", until you notice that a lot of the low notes are actually missing. Interestingly enough, the output from the bass unit's amplifier is not rolled off (significantly) below 80 Hz, which means that the driver does end up getting signal below Fb. The amplifier must incorporate some sort of dynamic EQ though, because even when turned up, there's no sounds of significant distress from the driver when it's fed very low frequencies.

Anyway, with no very low frequencies to speak off, the "bass unit' had to go, and I decided to replace it with a subwoofer design based around the Dayton DCS205 8" subwoofer driver. For this particular design, I wanted a solution that had an Fb around 32 Hz, as my intent was to use EQ to address the low-frequency performance in-room, and the lowest band on the simple EQ included with the PC was centered at 32 Hz.

So, I went to work on a new Excel workbook to describe the design, and I eventually came up with an MLTL-looking design that was around 26.6 litres net and 45 litres gross, primarily due to the use of 21mm MDF for the build. The corresponding Hornresp sim showed a response that gently slopes down from 100 Hz to just above 30 Hz, just right for what I wanted. The workbook is also able to export a data file in the required format for easy importing into Hornresp, which made the whole simulation process a lot easer. Note that in Hornresp I opted to include in the model the effect of puttling some polyester fiberfill in the first section of the alignment. According to the sim, this would drop the resonance frequency (Fb) a bit, and smooth the response in the passband. Real-world measurements of the built subwoofer confirm that the added filling achieved these goals. Note also that the predicted frequency response in Hornresp is slightly optimistic, as Hornresp does not account for the impact of box losses. The rolloff from 100 Hz to 40 Hz is slightly steeper than predicted, and the "corner" at around 32 Hz is a bit shallower.

Results
After building the box, the first thing I did was perform an impedance measurement, which suggested that Fb, which turned out to be around 33 Hz, was pretty close to that predicted by the Hornresp simularion I also performed some linearity tests, to see if subwoofer maintained its frequency response at higher input power levels (which would happen if port compression was low). Hornresp predicted that Xmax would start to be exceeded at 24.3V (the equivalent of just under 150W), and I tested at up to 25.4V (the equivalent of just over 160W). The subwoofer maintained its composure up to about -6dB, and then vent noise started to become audible. Still, it reached around -3dB from the peak input, or basically 80W, before the response at lower frequencies changed noticeably (according to the measured response), As this subwoofer is not going to see anything more than 25W in actual use (it's going to be powered by the Logitech X530's amplifier, after all), it looks like I'm never going to hear that vent noise - a good thing because this subwoofer is going to be located about three feet away from me, right behind my desk. Peak THD is also pretty low at 5.22% at about 20W input, most of which is 2nd order, so a lot less noticeable and objectionable. This suggests that the subwoofer is going to sound "clean" in actual use, and I can confirm that it does.

Conclusion
After messing around with tapped horns for awhile, it was nice to return to a relatively simple alignment, and this little subwoofer based around an 8" driver delivers all that I need for my multimedia system. If I was building this for another purpose, I might likely opt to flare the port's exit a bit, to reduce vent noise and compression effects at high volumes even further.

CAPITAL Audio Fest 2022 Room 310​

Nov 11-13

I wanted to introduce to you the new excellent and fine sounding base driver AER Studiobass 2 (15 inch) that I finished after many dozens of hours of work. I hope that you will be amazed as much as we are. Kind regards, Filip

On the pictures above on the left side is the old Inferior driver and on the right side the beautiful sounding new driver
It is the only Base driver to my knowledge on the world market that has a flat suspension.

Hi,

I bought some Surface mount LM317 and LM337 regulators sometime ago. Now I need to use them, and I cannot identify which is which. The markings are very much like data production code rather than device type numbers. can anyone tell me how to tell which is which?

Velodyne Optimum 1200W Plate Amplifier (NOS)

I have a mint (never used, never mounted) plate amplifier for the Velodyne Optmum subwoofer.

This is currently listed here: Velodyne Optimum 8 1200W Subwoofer Amplifier New 100 Working SN700431019 | eBay

I would accept selling it for $225 plus shipping and PayPal fees.

Hello, I have a set of two different brands of capacitors to install in my Nikko alpha ii power amp and can't decide which are better to use.
When the amp was new, it came with 10,000uf 63V 85 degree ones that had been changed out to others before I got the amp.
The ones that were in it when I got it were Jamicon 10,000uf 100V 85 degree units.
I am doing a total re-cap of the entire amp and figured I would replace the filter caps as well while I have it all apart.
I purchased a kit with all caps for the amp, and have no issues with any of them except the filter caps..... and reading all of the forums has got me a bit confused.
Have new caps from Mouser here or new caps that came with the kit.
The choices are: EKMH630VSN103MA50S Nippon United Chemi-Con 10,000uf 63v 105 degrees or Kemet ALC70A103EH100 10,000uf 100v 85 degrees.
I have read some bad things about the Kemets used as power supply filter caps, but not sure if it pertains to these particular ones. Specs are not too bad on either....
So hoping I can get some suggestions from those who know more about this than I do.
Note: I posted this also in the Parts Thread.
Thanks!!!
Russ

I would like to get advice on choice of a 6" - 7" fullrange driver for a backloaded horn.
Man years ago I built a BLH based on Ron Clarke's Austin126 design. It uses a Fostex FE108ez and I am very pleased with the result. Now I wish to build another BLH for a larger room and with a larger driver. It will be fed by a push-pull 300B 20W amplifier. I am thinking of basing the cabinet design on the Austin166 but I wonder what driver to use. The exact dimensions will of course depend on the driver parameters.
The music will primarily be classical orchestra and opera. Voice and midrange clarity is important but deep deep bass is not. Age and tinnitus means that response above 10 kHz is not so important. The listening room is 20 sq.m and the listening position is more or less on-axis.
An "obvious" choice would be the FE168ez but I know that there are newer drivers on the market (MarkAudio etc). Any suggestions? My budget limit is around the cost of the FE168ez (€300 - 400)

Thanks / Michael

I was gifted a pair of Def Tech BP2002 recently that needed some minor repair and I’ve got one fixed but kinda stuck on the second and hoping for help.

The amp turns on but that’s all I can tell because the two potentiometer for the amps need to be replaced as the posts are sheared off entirely (and I think set to their lowest volume). They are both marked as A5K but that’s all I can tell. Any help appreciated.

Pictures below:

What is the best type solder for heat sensitive components

This is a mini usbdac.
It has no exaggerated data. Only 16 bits 44-48k.
But his voice is good. You can plug in USB and use it directly. Or jump to an external power supply.
I recommend ac9-0. Use ONSEMI 7805 voltage stabilizing IC. Add three 1000uf low ESR capacitors.
in my opinion. The DAC should preferably use an external power supply. It can avoid the sound of hard disk in the computer. Or the noise of your appliances.
There is no need to pursue high data. CD discs also have only 16 bit 44K. But no one will think that the sound quality of CD is not good enough. I also make many 24 bit 32-bit 192-384k DACs. But I don't think it will be better.
The biggest benefit of using usbdac. Not a performance indicator. Instead, it can use ac9-0 power supply.
Plus voltage stabilizing IC. It can solve the interference of computer or mobile phone.
I found a Meizu 16xs mobile phone. Connect it.
It has a good sound without any settings.

I've searched the site for something similar to my problem, but there isn't anything that fully complies to my situation. So here it goes:

Looking for ideas on where to start. The amp was refurbished by me. Original schematic, no mods. Changed all electrolytics and transistors on the input board. Replaced feedback wiring (original wiring was weak/corroded at the input board connection). As is known and common knowledge, this amp model has a bit of very low level buzz (I wouldn't call it hum, it is more a kind of 60hz plus lots of harmonics), and this buzz can be heard with your ear pegged to the mid woofer and/or tweeter. But it is inaudible a few inches away. Quite normal.

Next step in refurbishing this amp, was to add speaker protection. I installed a Chinese completely assembled rig, which includes a 120V to 12V mini toroidal transformer. So it was very easy to get this thing going inside the amp's chassis. Got the 120V from the power distribution strip inside the amp, which feeds the amp's transformer after the power switch. So the speaker protection board is powered up/down by the main power switch as well.

The rest of the Speaker Protection board is wired this way: Input ground, directly to star ground point. Input positives, wired straight to each channel's output stage positive.

Speaker posts are wired this way: grounds go directly from the speaker posts to the star ground point. I saw no point in wiring the speaker grounds through the speaker protection board, as this device is common ground and does not switch the ground, only the positives. speaker post positives (+) go to the speaker protection device's positive outputs.

Input board is wired this way: main ground wired directly to star ground point. feedback grounds, directly to star ground point. Feedback positives, directly to each channel's output stage positive.

The amp works OK, but now the "buzz" is appreciably higher than before. It can now be heard (albeit faintly) a few feet (4-5 ft away) on a quiet morning through 90db sensitivity speakers.

The star ground is bolted down this way, from top to bottom:

Input board ground
Feedback ground
Speaker protection board input ground
Speaker negative posts
Chassis Ground


Before doing anything, I'd like to read your ideas on how to reduce or, possibly, eliminate this buzz.

Cheers!
Luis

Hello.
CD player XINDAK MUSE DELUXE 1.0.
Power on,but no display and any fonction.
Only on/off knob works on front panel.
All 5 fuses are ok.
All voltages of power transformer are ok.
With remote control power on/of working.
No service manual
Please need help.

Hi All,

I just finished building a pair of Audio Nirvana 10" Drivers in their 2.8 "Big Port" cabinet (the large pic below) and I am looking for something to line the port hole at the bottom, which is 6". When I look online (see little pic below) it seems pretty common, but for whatever reason i can't seem to find anything. I suspect it's maybe a matter of terminology and I am not searching for whatever this thing is called? I do find some port flanges, but not for 6" cutout. I was looking for something to line the port that I could attach some grill cloth to the back of, to keep curious hands out of the speaker.

Thanks for looking!

Musical Fidelity, well regarded as Hi-fi, added new equipment back in the days (that technically would contaminate the signal) in an attempt to increase audio listening pleasure. This was a tube stage that connects before amplification, and I think most folks know about this. My type of questions always get called effects devices and ignored or told to be moved to instruments and PA

My system is getting assembled, according to the details further below from my thread in the class D area to discuss the amp boards and power supplies. I need some direction with the tubes, some peer reviews and suggestions would be very highly appreciated

I am about to start ordering some online kits and boards that are tube based. I think I need one setup to provide channel tubyness and I have the desire to have one or two aux channels that have a tube based preamp and tone on them that are switchable to take them out of the circuit

Tubyness
I have selected this device for channel tubyness, may be able to get away with 3 units to flavour my 5.1 channels independently. I won’t be using the .1 output of the decoder, instead the signal will be routed in the decoder to the main L and R speakers. I hope to use the unit flavouring FL and FR as the system headphone output too and the signal out from this lil amp with have a low passed signal for system subwoofer

• Am I heading in the right direction with this board?
• How does it work without output transformers?
• Are there any output transformers that may enhance the task that I am asking of these?
• Are input transformers with this of any merit?
• Is it ok to run the headphone output into the input of the class d boards?
• I would like to run a switching power supply instead of a "ring cow". Is this ok to do with this design? Should I take out the regulator stuff out of this board if I find a switching supply?

SIngle ended tube triode amplifier for hifi 6N5P 6N5C Headphone amplifier class A (will order 1 after posting this)

Aux channel preamp
This one looks interesting. I have 8 of these tubes on hand, and they are nice golden NOS Russians. I am going to order this board too and see if there is a way to increase gain and to mod to a tone unit too

• Am I heading in the right direction with this board?
• How does it work without output transformers?
• Are there any output transformers that may enhance the task that I am asking of these?
• Are input transformers with this of any merit?
• Is it ok to run the output of this into the input of the tube headphone board?
• I would like to run a switching power supply instead of a "ring cow". Is this ok to do with this design? Should I take out the regulator stuff out of this board if I find a switching supply?

6N3 Preamplifier Circuit Board

This one is also attractive, but I'll only have the tube that comes with the kit
- Is this a better option?

TR2 6DJ8 ECC88 E88CC 6922 Tube Buffer Pre-amplifier


The following is from another thread in the class D area and provides the background into what I am doing. Eventually, the hope is that I would have played with lots of gear and upgrades

I am actively putting together two systems:
System 1 - 5.1 for our home which serves as home cinema and home studio and used for studio tasks usually about once a week. This is an open plan type home that contains the kitchen and adults bedding in one room. Another same sized room is attached, with an amenities' room separating the two. A full length room run alongside the two main rooms and serves as my workshop, large double sliding doors from main room to workshop. These areas are contained in a square house structure

System 2 - 2.1 mobile box with 3 aux amplifier channels outputs, for a portable setup, which can supply extra amplification on demand with extra speakers. This will be installed in the workshop in a manner that allows easy removal. Mainly for listening to music while I am working, as well as for testing stuff without having to rip into the home system (I hope the logic for common device models is now apparent)

Request
The living room is not a place for a PA system, neither is the sound quality and ability of most of this sized PA systems out there for portable use acceptable. System 1 will be in operation here virtually 24/7. Think of these as being in the same category as the high-end Japanese audiophile disc players that feature mic inputs. I do not believe that anyone would be upset about such a disc player being discussed in a Hi-fi forum, so please may I request that discussion on an amplifier with the same feature doesn't upset anyone's sensibilities
Please regard these as a Hi-fi want to be setup. Both will be used for audio and video reproduction and appreciation and when liquid courage hits the spot, these systems should invite one to grab something and let loose

Desired feature:

• An ability to keep electronic hardware and speaker driver models common to both systems
• Emphasis is on quality quite nighttime sound reproduction and ample headroom without loosing composure for other times
• Switch power supplies (desire to stay away from "ring cows")
• Tubey audio signature (prefer the sound of the 300b amp for audio)
• Engineered with the ability to input a live performer or two on demand (In other words, beautiful reproduction of prerecorded material, containing the "studio to mastering" process internally for a seamless jamalong)
• Low pass channels to be either about; 400 clean watts into 8 ohms - 400 clean watts into 2 ohms - 2 x 200 clean watts into 4 ohms each
• High pass channels to be about 100 watts clean into 4 ohms

This thread is for the tube devices that will be contained within

I have been saving for this project for a while, and in the meantime pouring over catalogues and specs and pestering folks with uneducated questions and ideas. Time to get to work on these, so I have ordered these items:

Signal IO
This unit will get fitted inside the amplifier case and provide most of the signal IO and act as the brains and system overall volume (has remote) as well as individual channel adjustment
4K@60Hz HDMI 2.0 Audio Extractor Converter DTS AC3 5.1CH Digital Audio Decoder ARC SPDIF Coaxial PC-USB Bluetooth Audio Input

Amplification
To be trailed as the low frequency amp
AIYIMA 500Wx2 Digital Power Amplifier (PSU on the board) x 1

To be trailed as the main channels amp and low frequency amp
HIFI Power IRS2092 500W Mono channel Digital power amplifier x 5
+ Lusya Dual DC 36V Output LLC Soft Switch 500W Switching Power Supply x 1

To be trailed as the main channels amp and bench amp
TDA7492 Amp Class D High-Power Digital Amplifier Board 2x50W (to run in bridge mode as a mono amp) x 1
+ 24V switching power supply board 4A 100W x 1

Speaker drivers
Low frequency
Dayton Audio RSS265HO-44 10" Reference Series HO DVC (delivered) x 1

Main channels
Already have a number of various pairs of bookshelf types on hand. Working on an interesting 6" coaxial speaker alongside this project, I am using some very interesting sounding drivers that I auditioned and bought, but I fear derision on my choice here

Reason to post thread
I am getting some promising looking kit that might help me acquired the desired sound system. Please guys, help me with peer review of my choices and suggestions to gear that I may not have noticed. I know create folks out there will have some great ideas too. Please help with mod suggestions as well as education pointers in anything I may be lacking. This will also be a log for me to help keep track of my project

Thanks and regards
Randy

Hello all, I'm new to this so hopefully i can get some help and guidance.

Basically i have a powered behringer PMP4000 going to EV ZLX 12P active speakers. I'm taking the connections from the non powered side of the desk to the speakers, nothing from the speakon connections.

4 peice band. Bass, both guitars and vocals going into the desk. Our singer has a vocal processor also. I connected all in and turned all down, with the gain i started to put up to i seen it was just fine or in the yellow. Did this with all then then with faders star put volume to FOH. However when we get going its up to red all night. Do i need to change the desk? Any help would be appriciated.

Long shot BUT I know there is a lot of intelligence roaming around here so I thought I'd ask the question.
I have a desktop fan and the grease/oil keeps either drying up or going gooey causing the fan to spin slow. It is a bush type and I've tried singer oil, molybdenum grease, light machine oil, lithium grease, high temperature bearing grease, even marine bearing grease and it only lasts like a week of use.... dam annoying. The one at work does the same thing.
I could try replacing the bush with a ball bearing type but that's a lot of effort as it's probably an odd size.
If anyone knows anything else I could use let me know!!!
Cheers

Pair of used AudioTechnology 18H52-06-13-SDKA-LR

Located in Australia, will ship US/worldwide.

Selling the pair for 300 US + Shipping + PP fees.


T/S Data
Fs 32 Hz
Vas 50 Liter
Qms 4,92
Qes 0,27
Qts 0,25
Re 5,4 Ω
Nominal Impedance 8 Ω
BxL 7,4 N/A
Cms 1,28 mm/N
SD 137 cm²
Mmd 12,3 g
Mms 13,2 g
Rms 0,54 Kg/s
Power handling 120 W
Acceleration factor 559
Efficiency SPL 90 dB
Sensitivity USPL 92 dB
Efficiency Bandwidth Product 121 Hz
X-Max 4 mm
Max Excursion 32 mm
Inductance @ 1,6KHz 0,09 mH

Complete amateur with some experience but plenty of enthusiasm.... The last device I worked on was a 1970s solid state hifi amplifier with two 10,000uF capacitors smoothing each channel. On the bench right now, is an early '50s table-top radio which has two 16uF smoothing the mains.

Technology and purpose are different, I know, but the difference seems enormous.

• Sugden A48: solid state, 45W, 'hifi' (high bandwidth, low noise, etc.)
• HMV 1121: valve, <5W, 'lofi' (adequate for AM radio)

What are the issues at stake?

Thanks

MFSL has been in the news. I first became aware of MFSL in the late 1970s; by 1986 I had placed a project with them.

Herb Belkin was a larger-than life figure. So, here's a link to my memoir of him.

https://positive-feedback.com/audio-discourse/mfsl-herb-belkin/

The photo is of Herb (second from the left) circa 1974 with the then line-up of the band Genesis. Herb discovered and signed The Raspberries and Grand Funk Railroad, among others, while working for a succession of major labels before stumbling into MFSL via his connections to Pink Floyd. Rest in Peace, Herb.

Hello,

Before I build a circuit I like to understand how and why it's constructed as is it. Lately I've read "The audiophile's project sourcebook" by Randy Slone, and one of his preamp designs catch my attention. It's really nothing more than a non-inverting opamp (voltage gain about 13,5), see the attached schematic. But what bothers me is why I can's tell the reasons for all the components.

- Capacitor C3 in the feedback loop is there for limit the bandwidth of the amp, I assume? But to which frequency (value of C3 is 36pF)?

- The purpose of capacitor C2 should be to make DC gain zero, since it will act as an open circuit for DC. Therefore no need for input capacitor?

- C1 and R2 and can't tell why he put them there.

- R5 is there to isolate the opamp from eventually capacitive loads (?).

Appreciate some answer, unfortonetly the book doesn't explain this, for some, obvious things.

Not very experienced here and running in circles so hoping for an helicopter view from more experienced users or an hindsight from experiences..

I am able basically to set only three out of four biases in their sweet spots (300-320mV).

The NPN left channel high-side bias is the problematic one (measured at R302 and set by R326 trimpot) as turning the pot makes no sensible change; the bias at startup is rather low at 50mV (while all other biases rise very promptly to sweet spots) and sloooowly rises up to 200-250mV at maximum over some 10 minutes or so.
I checked the output board, NPN side, comparing the channels and while components all seem to be working (diodes are ok, transistors in circuit appears to be ok too - except bias voltages on 0,2ohn 3W emitter resistors which are rather different on the 6 output transistors), I thought everything was ok.. then read about the Odep system (the front led is always lit as if the amp is fully working) and thought it might be the one to draw current from the output transistors somehow..

I checked voltages on the odep board, and it had not been possible to properly set odep + of the channel in question. I happened to find a resistor which sensibly drifted out of spec (R134). Substituted it and then hoped.. but still the amp bias is not working and odep + is still not

I then decided to take out the six output transistors but they all seem (seem, meaning that my diode tester procedure might not be fool proof, but I would assume they are all ok) to be ok and put them back in.

Of course I'll try to post a schematic as soon as possible, but any hint how to go on with what possibly to check will be appreciated, thanks!

Hi,

I have self made 60cm high speaker stands to give away.
The foot and speaker shelf is 20x25cm.

Pretty heavy, made of 4cm chipboard. Bottom and upper part 4x20x25cm, in between two legs 4x10x52cm (approx). Birch veneer.
I will try to put some pics soon.

Please be quick as they are on their way to the local dump... unfortunately...

Decided to go a whole different direction with this project when I found out about the F6 drivers by Lii Audio. My logic was that with these I could make my modest system much simpler and since my crossover building skills are non-existent, these were the perfect solution. They're wired in series-parallel for an 8ohm load and with my diy sub everything sounds perfect for me!

Someone mentioned that I should have a lot of comb filtering with these having this many drivers all playing the same frequencies and I'm wondering what the thoughts are on this? I a/b'd them with my smaller 3-way baffles and can't tell much difference other than these have a larger sound to them. Don't hear any weirdness going on. What I could find basically indicates that it isn't much of an issue in a vertical array and is inaudible in many other instances. Just curious if this is an issue I should be concerned with.

Chris

Hi

I bought this cable here https://www.audiophonics.fr/en/cabl...lded-power-cable-occ-553mm-o165mm-p-6456.html

Now I need to remove the Teflon insulation surrounding each conductor, it's really thing as you can see on the pictures. I would really like to avoid damaging the copper stands, I already had to cut away 3cm of cable because the only way I managed to remove the Teflon was with a knife and peeling it a way like potatoes. I tried 3 different cable removal tools (see picture= and couldn't get any to work, maybe they are not suitable for this situation I am not sure.

It's really elastic, almost like chewing gum and it's a very thin layer.

Suggestions are welcome, I have never done this before.

Best regards and ty vm

hello friends, I am looking to repair a the epicenter at the beginning it started to send a very high frequency or a strong and annoying bass now it does not regulate try to try another control and I had no luck I already checked potentiometers and operational amplifiers and I have not been able to make it work, thanks for your support.

First is a opamp decoupling socket.

AVX Tantalum Capacitors
Murata MURATA C0G 5% Precision Capacitor
TDK X7R 10% Precision Capacitor
Murata MURATA X7R 10% Precision Capacitor
Koch Corona 3U Gold Plated Beryllium Copper Female Pin
Japan Hirosaki 63sn solder

EDIT: Forgot to add in that it advises against using it in a heavy negative feedback circuit.



Second is a Dual Single DIP8 to Single adapter.
It claims to increase the sound quality and drive force.
It puts the second chip as buffer, but idk if its that useful.









Imagine combining the 2 with a Dual to single adapter and using 4 opamps instead of a single dual one with the decoupling "socket".

EDIT: messed up the sizing.

Someone gave me a Luxman R-104 receiver as partial payment for fixing some of his other equipment. He said it worked and it does; except the tuner does not remember any stations when the unit is turned off.

I looked for the usual culprit - a small battery by the logic chip. I saw what I thought was the battery but it is a capacitor. I think this is the precursor to the "supercapacitors" of today; it is rated "0.047 F / 5.5 volts." In other words, 47000 uF/5.5 volts.

I cannot access this part of the board without practically taking it out, so I put it aside. I guess I will solder test leads to the board and see what's up. But I was wondering if anyone else has any experience with this problem; I'm thinking it's pretty much a slam dunk to just replace this capacitor and restore the memory function.

So my question is, am I being too optimistic? Does anyone have any experience with this? Logic circuits in receivers is something I really don't know much about; I am capable of making only the basic checks. I'm all over everything else.

I can't find service literature for this unit. I know it's not one of the sought after Luxman units, but it is really nice - a pleasant surprise. It lacks nothing, except high output power.

So thanks for reading this.

Hi,
Is it matter?
Mid and low-sub are in separate chamber in a 2.5-ways floor standing configuration.
Mid covers 80-2000Hz (1 driver), low (sub) cover 38-125Hz (1 driver).
The ports located between mid and low-sub drivers.
Mid has 2 ports and low-sub has 2 ports.

• what things should I be looking for in the replacement drivers to better match the existing cabinet?
  
  
• in the case I need to make mods (easy/simple) to the cabinet, what tools should I use achieve this?

Thanks in advance for the replies.

We all know the flat T/T belts are nearly used universally for belt driven T/T's. Most know of their big disadvantage, they stretch which induces speed incontinences. The answer for many is to use Mylar tape belts which do not but these are a little fiddly to make up.
So what if we combined the two. have a rubber flat belt on the inside with a Mylar belt stuck (adhered) around the out side of the rubber belt. Surely that would give us the best of both worlds.

Cheers

So far I gathered a pair of K-402 horns, Crites 15" drivers, and most of the wood I'll need to build out a pair of multi-entry horns based on Chris A's work. The last major purchase I need to make is the compression drivers. I would love to use TAD-4002's but they have become unobtainable (with original Beryllium) from what I can find... That said, I think I've narrowed it down to 3 choices:

RADIAN 950BE PB
BMS 4592ND
Celestion AXi2050

Which would you guys recommend? Anything I'm missing one that should be on my short list? I need to cover roughly ~475hz - 20Khz...

If it matters, my center channel will be Bill's "1/2 of a 3D printed wave-guide" using a B&C 250 CD.. it will be active not passive however. Also I do not care that I would need an additional channel of amplification with the BMS option in order to avoid the reportedly crappy passive crossover that is available. Goal is end-game speakers so cost (within reason) can be ignored.

Second question is related to how to make all this look nice? I'm going to be cutting (giant) holes in my wall to mount all this in-wall. They will be located about 1/3rd of the way from the side walls (so NOT in corners). I know that I need to toe-in the speakers towards my MLP and in my mind I'm struggling to picture how to do this in a way that doesn't look like somebody just stuck a giant speaker in a hole-in-the-wall at an angle! If I were competent at 3D design I'd try to draw something up so they have a more built-in look but alas I am not (it's on my list). I will definitely be building grills for the horns. If you haven't guessed I have a wife ;-)

Anyone got any ideas of how to integrate the angled box into the wall is some sort of elegant way?

I recently picked up a PS Audio Phonolink Phono Preamp from the early 1990s. Currently, it's working great, dead silent. It really must not have been used much, the exterior is a 8/10 and inside it looks like it just came out of the factory 10/10. Hoping someone might have a manual and even better a schematic. Given its age, it's time to recap. If anyone has any info about this unit, it would be greatly appreciated.

Hi guys,
How do you find my new build?
Inspired by B&O Beosound Edge.

Movitone Orrbis:
Arylic Up2stream pro v3
Arylic DAC board
miniDSP 2x4
Amplifier:
ICEpower 700AS1 + 200AC + 200AC (350W + 100W + 100W @ 8 Ohms)
Speaker drivers:
SW26DBAC76-8 (10” subwoofer)
SB12NRX25-4 (4” midwoofer)
SB21SDCN-C000-4 (20mm tweeter)
Case:
MDF with 8mm powder coated aluminum face and back plate.
Laser engraved leather surround.
Dimnension: d500 x 112mm

Going to upgrade to Arylic Up2Stream HD DAC and miniDSP 2x4 HD

Remodeled Case to fit Satory 5" midwoofer and Bliesma T25 tweeter.

I am trying to recover use of the control buttons on the front panel of my NAD T753. Not sure what happened, but a good summary is "blunt force trama" probably from my kids playing pushed the Tone Defeat into the faceplate. I nolonger can use any controls on the front panel ... except for tone defeat. (go figure!)

I want to carefully dismantle enough of the unit to allow me to see what actually happened. But I am now stuck.

I need to remove the Volume Control Knob for the motorized control. The control body itself is welded to a circuit board. I *hope* that if I remove the knob on the front, I will see a nut or something around the shaft that I can then remove allowing me to remove the board from the back of the front face plate.

How do you get the knob on the outside of the unit off? It is firmly attached.

Thanks.

Guys,

this is a question that i had since many many years back, but it was until today that i dare to ask

so, why most of the mid grade ( QSC KW series , EV ETX, JBL SRX 800's ) V2 way or 3way PA cabinets
max SPL ratings are around 135 or 136 dB's

is because the limits of physics or because the limits of the drivers for that given price ( max 2k )
as far as i know the HF driver is padded because it have much better sensitivity that then LF driver
so the LF cant cope with the HF power limit and that is why manufacturers can only achieve around 135SPL's

i saw the new MEYER Panther series that are rated at around 150dB's SPL but those are linear cabinets and i think they cost above 8k each
but what about the 2 way single point PA loudspeakers

hi all i have this sick skytronic 0-30v/010a psu,its busted and need a schematic for it,any ideas?

Can someone please explain how an aperiodic loudspeaker generates additional bass? A closed box (acoustic suspension) is easy enough to understand. Similarly with a ported speaker - more bass due to the air in the port resonating at a frequency lower than fs and adding to the bass being produced by the bass unit. But an aperiodic enclosure doesn’t have the supporting bass resonance, and if designed correctly, the flow resisting vent will lower the drive unit amplitude. So how is the extra bass generated? There’s obviously a fundamental piece of information I’m missing because it really makes no sense at all!

Hi all, I made some midbass horns a while ago, they are fitted with vintage 12" drivers, Richard Allen cg12 super qt apparently 0.105.

The horns are front loaded and although very low in waf relatively small, about 4ft2 mouth 4ft long.
ATM I cross them to some dh1a in hp940 at 750hz then to Beyma tpl150h at 2500. These are all driven with 6e5p PSE amplifiers via a pair of minidsp 2x4, about 5w. I have been keeping an eye on eBay for some of the better EV horns.
Idiosyncratic setup I know, more a rolling experiment than a hifi.

So I thought I'd try a sealed bass section to compare against the horns, if they are ok I'll get waf points and get some of the living room back! I'm prepared to lose some efficiency of course (presently ~103-105db/w) and have more powerful amplifiers available, but would like to maximise efficiency within reason.

I have a few vintage 12 inch high efficiency drivers to hand, Goodman's audium 61 etc but fancy trying a pro audio 15" to try and retain some of the horn speed and thwack.

My days of spending hundreds on drivers I'm afraid is behind me, so budget is an issue.
I've spent a few days searching the forum and the top end of budget would be perhaps faitalpro 15pr400 but cheaper is better if I don't have to sacrifice too much.
Pooh recommended celestion tf1530 which In the UK cost about Eminence delta territory.

I have subs but getting bellow 50hz or so would be nice, my horns are reasonably flat to 80 in room. Cabinet volume I can go to 150l and I'd like to try sealed.
Priority is probably voice region.

Any other driver recommendations or ideas or links to similar projects much appreciated!

Many thanks
Enzo

Pretty sure ive seen this done elsewhere but heres the method of output transistor mounting im looking at for my headphone amp.

The to126 transistors (bd139/140) are bent horizontally and faces up. The heatsink is coupled to the exposed ground plane by the mounting screw.

I see benefit in this from better heat dissipation and less leg inductance (the transistor legs would be cut as short as possible)

But what about increased parasitic capacitance? The transistor is now sandwiched between two conductive elements. Is this a good thing? And should the layers & heatsink be connected to power traces instead of ground? Thanks in advance

I have to sell accuton passive radiator p280
Unuse ,brought for my DIY project and change plan to install 4xp280 .
Two are already brought and let go them.
2 for $300 plus shipping
Come with original box .
Photo is not passive riadiator they are S280.

Passive photo later I will post here

Thanks

If anyone is interested in 90% of the LS3/5A sound for 350 bucks plus shipping, I have just the thing. They have a couple dents, and are Chinese knockoffs, but that's why they're so cheap! Pictures attached. As you can see they are not in perfect condition, but they are still gorgeous to look at, especially from a listening position. I had KEF LS50's when I first bought these (I am the original owner by the way, purchased directly from Mistral Audio. I promise I'm usually more careful with my gear!), and after listening to these for a couple months the LS50's were quickly sold. Both formidable speakers, but the Mistral's to my ears were much more coherent and natural sounding.


Speakers work perfectly, and sound as great as the day I bought them. I will soon be building what has become xrk971's Vanguard speaker, (which you should check out if you are interested in LS3/5A like speakers!). No idea which speaker sounds better between the two, but I got most of the parts for very cheap at a parts express garage sale to build the early version Vanguard (I'm not sure if X has changed the crossover or if he is simply commercializing the design he generously shared for free here) so they win by default by being lighter on my wallet! I really like these, but they gotta go!

Hey all, I have been browsing for months now, seen a few members builds, and @speakerscotts build thread. Danley horns have always fascinated me, and I'd love a clone. I have extensive woodworking knowledge, but I am having some issues with Scott's thread and details, and ensuring I get the angles on the horn perfect, and getting the hole separation perfect.

Scott's plans mention multiple times 60x60 coverage areas. Does this correspond with the throat angles of the horn? If I go by Scott's plans to a T in SketchUp, I am getting throat angles of very near 60° laterally, but only 53° vertically. His plans work perfectly to address the small drivers exiting at 100° through the flares, but the throat angles confuse me more and more.

In addition to the above question, are there other full detail plans for a synergy horn clone or something similar with a nice large waveguide that might be easier for me for my first time?

New newer used excellent audio capacitors.
MIflex KPCU - Copper foil +paper+oil, matched pair
I sell 2x 0,33uf-250V vertical position mounting like DUELUND dimesion 26x50 one matched pair 22€/pcs
4x 0,47uf-250V horizontal position dimension 30x50 two matched pairs 24€/pcs
Plus shipping cost.
Excellent for decoupling or bypassing bigger caps.
Prefer Europe selling.

I emplore you of the internet!
i am a pooor college student interested in ESLs. i need someone more competent than i to recommend a high voltage transformer to me! i would like for it to be cheap and readily available.
I expect for my panels to be four feet square and with 1/4 inch spacing.
Thanks

I am trying to decide what to do and could use a little guidance in deciding what direction to go. Most of my repairs are still thru hole, mostly double sided PTH, and I would like to use a de-soldering station rather than wick, which has been working but is cumbersome and potentially dangerous for the boards.

I have a Hakko 470-2 station with 802 handle, all in pretty good condition, well used in a commercial environment but maintained. It's been sitting for 10 years now and I pulled it apart for a complete maintenance checkup and found it needs a few things. The pump needs new vacuum flappers and filters, both still available and cheap. The 802 handle needs filters, probably a new nozzle, maybe a new cartridge holder, the little rubber accordion bit on the trigger seals but looks about ready to crack open and is discontinued.

1. So I can buy $50 worth of stuff and hope everything still seals and sucks correctly as my first choice.
2. Keep the 470 station but buy a new handle, what is compatible and is it worth it to go this route?
3. Sell the 470 and look for something else.
4. Buy the Hakko FR-301 system and get on with it. 😀
5. Buy an offshore knockoff Aoyue etc?

Recommendations and or some guidance would be greatly appreciated.

Cheers

l am in the process of prototype 300B amp based on JE labs circuit.
l want to use a meanwell adapter 5V 7amp to power both channels 300B output tube.
The heater of 6sn7 will also use a 6v ac dc adapter with ground elevation.
Is this feasible , will circuit work and safe?

Closed as are gone.

Free are new Modushop (Hi-Fi 2000) Galaxy 2U case front panels made in Italy and are available with 1 black (3GX28702) or 1 silver (3GX28707). They will be supplied with original mounting screws (M4 csk machine screw). These are anodised brushed aluminium and are 234mm wide x 84mm high x 3mm thick. An example in use is shown in a photo and is not part of this offer.

These suit the Galaxy GX283 (230x230), GX287 (230x170), GX288 (230x280) cases and ideal for replacement if reworking or require a new panel. Can also be used as a front panel on a DIY case.

I will cover postage (Australia only).

What other mosfet could work well apart from the irf3710z,
maybe work STP100N8F6 or IRFB33N15D IRF3415.
What do they think?

Alright, with family responsibilities i get very little to spend on myself.

I'm looking to experience a warm, mellow sound and unfortunately cant afford to spend over $1500 in total for the entire setup.

A friend has just bought a headphone/preamp (xDuoo TA-26) and speaks very highly of it being mellow in headphone. Link - https://xduoo.net/product/ta-26/

I don't like headphones. I want to be able to use speakers.

my question(s) - if I use this preamp (xDuoo TA-26) and connect it to what kind of amp to experience mellow sound? I'm planning to use some full range drivers from Dayton Audio or SB Acoustics with required xovers. P.S: I've some cheap Class AB Receivers and Class D SMSL and Aiyima amps at home.

According to you, what would be the ideal setup of system if you're willing to experience warm mellow sound under $1500

Hello guys, I´m building stereo pushpull tube amp. I´m from Czech Republic and I´m 14 years old, please sorry for my english.
I´m using long-tailed-pair type phase inverter with tube 6N1P.
The schematic:

Values: Ra1, Ra2: 100k
Rg1, Rg2: 2M2
Rb: 1.5K
Rt: 47k
Capacitors: 33nF
Anode voltage: 250V.
Main two problems are:
1. Balance - one output is 15% smaller than another (this is not very big problem, i can change anode resistors to get equal amplitudes)
2. Limitation. I play the music, amp is giving about 5W of power. Than I raise the volume and amp is distorting. It makes square wawe from sinewave. When I was troubleshooting the amp, I found that this distortion isn´t producing power stage, but long tailed pair. Can you please help me, what can I do? I tried to low the anode resistor to 22k, this was bad idea. On grids was 13 volts instead of biasing -0.5 to -1.5 volts. Than I tried to change coupling capacitor. No difference. Can you please help me? Thank you very much.

[ Moderator Edit: This thread split from here - https://www.diyaudio.com/community/threads/problem-with-long-tailed-pair-phase-inverter.320241/ ]

cogsncogs said:

You need to pass a little bit of current through the 6N1P and some voltage across it. I chose around 3mA for each triode and 100V across the anode and cathode. You can push your B+ to 300V as long as the anode to cathode doesn't see much over 250V during operation as the tail resistor will eat (drop) quite a bit of voltage across it...

You didn't specify what output tubes you plan on driving with this.

Click to expand...

I'm posting this question here because it is very similar to what is posted here. Hope that's ok.
I've got this circuit breadboarded. Without the 12W6 output section connected, with a 1KHz input I can get nice equal sine waves from both outputs of the phase inverter at about 150VP-P before clipping. When I connect the output section there is some kind of oscillation that happens at about 50VP-P, Looks like the attached photo. The first section phase splitter oscillates at about 5VP-P higher that the second section. I like to get some help figuring this out.

Hi all ,i have a bose waveradio (AWR3CG model),the cd player doesent work,I cant see the laser diode working in the pickup,i have tweaked the driver voltage and cleaned the lens but no light output,i assume the diode is dead,is it possible to replace just the diode as the optical sled isnt available,TIA.

For sale is a base kit (PCBs, parts, op-amps, etc) for the RJM Emerald RIAA phono stage, purchased directly from Richard in January of this year. You still need chassis, a mains transformer, and the other stuff like wires, switches, RCA jacks, etc. to complete this build. I have a completed Emerald I listen to routinely and I love it- very neutral sounding to my ears.

I paid $155, that's what I'll sell it for. Shipping extra. Can hand deliver at Burning Amp. Thank you for looking!

Amp power up but there output I resolder the inductors that are in the center circled the legs are broken off of them and the glue was not holding to the board anymore and also the three capacitors in the center two or fully detached from the board when it arrived they were none bipolar capacitors and I replace them with bipolar capacitors would that affect the cell from being able to travel to the outlets or where should I check next

I have a SET amp that I have used in the past to drive a compression driver. It has been sitting idle and I decided to check it on the bench before putting it back in the system. The input tube is a 404a, wired as a triode, capacitor coupled to a 6L6GC output tube, also wired as a triode. The B+ for the 6L6s is 300 volts. It is cathode biased with a 400 ohm resistor and a 1000 mfd capacitor. The target current is 40 ma. One channel is right at 40 ma. The other channel is at 26 ma. BUT, if I pull the input tube for that channel, the current goes to 40 ma. No problem, it's a leaky coupling cap, right? Nope, I changed both of them out and it still is at 40 ma without input tube, but 26 ma with. The B+ for both input and output tubes stays the same either way. I reflowed all of the soldered connections in that channel. No change. What am I missing?

I need a woofer for my project but need something very unusual. Because building a completely new woofer is incredibly expensive I wonder if there is a supplier for good woofers where you can make individual changes? Big brands don't always build new drivers, they use drivers that can be adapted for their purposes(even if that happens with other capital and other amounts, of course).

I would like to know how to solder thru hole film&foil Capacitors

Hi !

I have an idea to replace cathode resistor and electrolytic capacitor with LED or SiC Shottkey diodes in amplifier with global feedback in PP amplifier. The only question remain how to re-connect global negative feedback resistor. One of the options is to connect it the grid of first input tube but it will yield high EMI noise pickup. So better to keep where it belongs to - in cathode circuit.
I attached 2 variants - which one is correct?
Thanks in advance.

I recently bought a pair of premade DIY pass labs Aleph 3 monoblocks.

When I turn one on, silence. But both, and whine develops.

The only thing that seems to stop it is if I touch the earth of one of the RCA inputs to the chassis of one of the blocks.

Any ideas on what could cause this? Or how it could be corrected? It's rather persistent.

The attached photo show a portion of schematic from a Philips CD60 vintage CD player (there is another thread with more about repairing this player after some damage).

Note 6502, the BC338 npn transistor powering the laser diode.

It's possible that the +10v rail this trans. is connected to experienced a power spike, as one of the fusible resistors was blown (see other thread) .

The laser power was waaaaaaaaaay off after the fusible resistor was replaced and Laser Output Adj (3520) was tweaked in order to get a CD to boot.

Some discs still don't track well (bouncy eye pattern), or produce mild audible distortion.

It's possible the BC338 was "affected", tho' it tests "okay" (its hFE is a bit on the high side).

Suggest an alternative (maybe even an improvement).
In my kit, I have Toshiba 2SC2240 and BC547.

If you think the original BC338 is okay, say so.

Thx

There are just a few videos in existence showing an individual assembling the particular elements within the envelope. We see people using very small spot-welders being used, fabricating tiny metal structures...nowhere do we see a so-called "exploded diagram"...are these tiny structures a true industry secret?
Let's see if we can find diagrams of these structures...& try to improve performances by analysis & optimization.


-------------------------------------------------------------------------------------------------------------------------------------------------------------Rick...

I've been reading (searching the net) on the differences between the two:

1. It seems a bridge rectifier is more efficient in terms of the transformer construction.
2. The bridge rectifier has a bigger voltage drop because of the two diodes (maximum of .7 each)
3. Ripple is higher on a bridge rectifier

For an end user, I feel the transformer construction advantage might be not as useful.

In my case, I'm looking at two transformers which cost the same.

• 300VA 2 x 12VAC @ 12.5A (will be used in full-wave mode with ground center-tap. connecting the 2 secodaries in series to get 24VAC)
• 300VA 2 x 24VAC @ 6.25A (will be used in a bridge rectifier configuration)

Are there any other electrical advantages/disadvantages of one or the other? Is the current output the same/similar?

PS: I need +/- 30+ VDC after the rectifiers.

Thank you.

If any member has a CD3 power supply with transformer, I can make good use of it after mine has failed.

Not sure if this is a problem that others have had.

Regards all

Thanks

Well 🙂
Lets start with a picture.

Hi,
I am parting with a much loved pair of Curvy Changs that I built about 12 years ago they are fitted with FE206's (fitted with Decware type phase plugs) rather than 207's they have a shelving filter to compensate for the 206's rising response (at Scottmoose's suggestion) They are built from 24mm Birch ply and veneered in Zebrano and are very heavy. They have given me a lot of pleasure over the years and are in great condition, but its now time for a change of direction so they have to go, I'm open to any reasonable offers but they must be collected, we live in the Lincolnshire wolds in the uk, about 20 miles north of Boston.
Steve
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Top

Hello everyone! I've been in the need for a really good nearfield monitor speaker. I wanted it very compact and active. Also, it had to play at decent max SPL (around 90/93dB at 1 meter) in case I wanted it to fill my room. The FR had to be from 50 to 10000Hz (+-2dB) on axis.

For this reason my choice landed on the Dayton RS100-4 for its decent FR and good Xmax which is never enough for small drivers! The efficency is also decent with it being a 4ohm unit.

The FR doesn't quite meet the requirements but it seems like it can be EQd quite easily. I'll get a Sure JAB3-50 (it has a built in DSP) module to drive the speakers. Since I'm using DSP, I'll be making the speaker bass reflex because that way I can make an assisted alignment, also it's way more efficient than sealed.

3.6L net volume tuned to 55Hz with 2nd order HP filter (Fc=55Hz and Q=1,2) yelds to an almost perfect response. The SPL is also more than enough. This is the green graph.
But, in reality, tuning a small box so low is hardly feasible unless making a slotted port which comes with its own set of problems... mainly being much less efficient in terms of space and it also has higher losses thus lower efficency. If I use a round port I could make the box very tall and put the vent on the bottom, even if that wouldn't be very practical. Think about 11*14*25cm(3,85L). Even then I'd be limited to a 3,5cm port with a lenght of 24cm. This port has an airspeed of 31m/s (!!!) at 49Hz, with 30W input (not very realistic but I'd like to properly size the port), which is too high! I have to limit the power to 9W in order to stay at 17m/s.

So I started experimenting with passive radiators in WinISD, which also have their own sets of drawbacks, mainly the way lower efficency leading to a significantly lower max SPL (-2dB)!!! The two "best" radiators I could find for the price were the Dayton Audio ND140PR and the DSA135PR.

I put them in the same volume (3,6L) and tuned the enclosure to match the ported one (around 55Hz Fb).
The ND135PR required +18g (!) of added mass to tune at that frequency. I'm worried this might sag the suspension long-term. This is the blue graph.

The DSA135PR just +2g. With 30W input i'm VERY close to the 8mm Xmax for the DSA passive radiator but, between all the other problems, I could deal with this, if it wasn't for the massive loss in efficency. This is the red graph. I think this might be the best compromise, because even if I compare it with the ported version I'd be SPL limited way sooner because of that crazy high port velocity. Also I don't have to deal with chuffing.

The graphs do not include the filter.

How can I impove this design? Which one do you think is the best compromise? I would really like to keep the efficency of the ported enclosure without having to deal with the excessive port velocity. Do you think a slotted port would really help, even if it would make the box bigger? Thanks a lot!

I have an old (20+ years) set of these speakers that are starting to sound a bit "tired". Would it be worth replacing the crossover caps? The yellow caps inside say 4.7K 250. Is this the same as 4.7uF 250v? If worth replacing what caps would anyone recommend? Thanks

Alu Die Cast Cabinet: Monitor-Audio BM-100, Pioneer TS-X9 Bowers & Wilkins " ???"

I remember the good sonic quality of the speaker models mentioned here from early exhibitions and consumer shows.
I am looking to the B&W loudspeaker model, that is similar to the mentioned types especially to the outline of the "TSX9" from Pioneer. It was on the market between 1980 and 1990.
Who knows the model number?
And a second question: Where on the web is to find a test review and a frequency response of the BM100 from Monitor Audio.
Thank you very much. Here some images of the other above mentioned models.

Hi Guys
Been researching on parts to built my first horn speaker.
Due to my location, it would be ideal to use parts that I can purchase locally.
Looking into building a 2 way if possible with the above horns crossing over at 600-700hz. Size matters too as it’s for home use. Sensitivity of compression driver need not be high somewhere around 95-97 db or so would do.

Thanks in advance.

The history is short. I bought it for 15€. The device couldn't read any disc. I opened and the lens was not in the laser pickup. It's a typical fault in these series Pioneer laser pickups. I searched the lens but it was not inside the laser pickup. I thought to remove a lens from some Pioneer lasers I have, but these lasers pickups cost 100 or 200€ in the market. It don't worth. Then, I thought to use a lens from a chinese scrapped Sony KSS-240 or similar... I put the lens, it fitted perfectly, a drop of glue... and it works! It works perfectly. I adjusted a bit the "radial and tangential tilt adjustment", focus offset to O volts and perfect.

P.S: In the Pioneer PD-4700 service manual is where the grating adjustment is best descripted. If you want to know how to adjust the grating adjustment, there is the best description I ever found about it.

So, if you have a Pioneer laser pickup without lens because it had lost, get a chinese KSS and use its lens for to repair it.

I recently acquired a set of these boards and have read that there are issues with them. It relates to the bias and output transistors. I made the check of the bias as was mentioned in a previous forum and I get nowhere near the mv mentioned.
You are supposed to measure between the output with no input on and the middle leg of any output transistor, and you should get around 22 mv ideally. I am getting 1.4 mv. The DC offset is 10.4 mv and the ac ripple is near zero.

I ran the scope on the boards, and they do not put out the watts stated, only about 80 watts @ 8 ohms and just under 170 @ 4 ohms. The sine wave is clean with no ripples I can see, as I am worried about HF oscillations on this board.

Anyone has any thoughts on this, I was advised to change the 1k resistor to 910 ohms to have an ideal bias of around 22 mv.

Thanks Cheers Wayne

I asked a question here a long time ago regarding PCB for a Quad 405 clone. I built one and I like it very much, yes its an old design and there is a world of newer designs to utilise but each to their own.
I want to build another and gift the one I built to a friend, for the next one I would like to use 2x300VA toroid trafo and Elna 10,000uF caps that have been sitting on a shelf for a year. I have some extrusion as used in these cases Uniobox 2 - electronics enclosure kit - Lincoln Binns and want to build two mono units.
My questions are thus; where to find a good design for the two PSU required?
I would like to modify the amplifier circuit design to Snook or Net Audio, the boards in my amp are copies of the first Quad issue, the LJM clone. I see there is a copy of the 405-2 board available, which PCB is likely to need the least track cutting and component moves? On the 405-2 clone PCB I see that the input and output connections are spaced further than the first issues, design modification to avoid noise?

I read this thread from 2006 but nearly all of the links are broken; https://www.diyaudio.com/forums/solid-state/79508-quad-405-2-clone.html

I am looking for a saturable reactor for a General Electric e-126 colorama radio.

Hi, I again with my discussions.
I'm some time ago to update my old turntable, Aiwa AP2400, direct drive; 1982; with an Audio Techica AT 440 Mlb capsule.
For this reason I have read countless reviews and articles on current turntables.
I have focused on budget within which are Pro Ject Debut Carbon DC; Rega Planar 2; Pioneer PLX 1000
This last DD.
I read the argument of belt drive vs. direct drive, of which there is infinity on the internet.
The conclusion that arrives is that with audiophile purposes the belt drive turntables win and for DJ the direct drive wins.
The argument by majority is that the direct drives have greater motor noise when this is coupled to the plate, not so in the belt drive.
My dilemma is: I do not hear any Humm on my turntable, or on the speakers or placing a stethoscope on the arm bearing.
Also my reasoning is: how could there be Humm if the motor-plate turns at almost 2 RPM ?.
If I compare the specifications, the Humm of a direct turntable are superior to the specifications of a belt drive (Aiwa AP2400 has -70dB) (I clarify that the belt drive turntables in which the motor is outside the plinth do not enter into this discussion They are not in this budget)
And finally I saw a lot of post where there are complaints of Humm in Pro Ject and Rega, should do some DIY work to improve it.
That's why I'm in doubt about acquiring the Pioneer PLX 1000 or Pro Ject or Rega.
Greetings.

Regards,

Some "leftover" audio boards found. LM4780 stereo amp boards, assembled, tested, new and unused. Boards with power supply ( rectifier and 4x 4700uF on board..)..premium passive parts. Only needs transformer.

Three boards available, two are identical, one with different capacitors. Dimensions 145x65mm.

Price reduction: 30€ per board. Shipping ( registered with tracking..) 6€ for EU, 10€ other countries.

Regards, Davorin

Earlier today, I posted the following on Audiokarma. I think it should be on diyAudio too. Some of it I posted already in bits and pieces, but now it's more 'compressed', and under a better header:

For data on tubes, this is the site I go to:

https://frank.pocnet.net/

Note the "Much More" button in the upper right corner on that site. It leads to a wealth of tube manuals and other books on tube technology. The following link for instance leads to the sub-page with the Philips Series of Books on Electronic Tubes, to which I contributed a couple of books that I scanned myself (but not all are in English though):

https://frank.pocnet.net/other/Philips/SeriesOnElectronTubes.html

Scans of the "Philips Technical Review" and of some other series of research papers by Philips stood on a personal internetpage that was part of a larger Philips site, but some years ago they were all taken off-line. Luckely the scans of the "Philips Technical Review" series all found their way to the "World Radio History" site. But the other series of research papers did not. The same goes for the handy Excel indexes for all the series. But I downloaded all at the time and uploaded them to Google Drive. The links in the indexes themselves don't work anymore but they still are a handy tool for searching. Here are the relevant links:

https://worldradiohistory.com/Philips_Technical_Review.htm

https://docs.google.com/spreadsheets/d/15eXWd1afpPjQYcKAPBACx0oJB_qvy1za/edit#gid=248973280

https://drive.google.com/drive/folders/1m9aE3j9lX5IpH0vO0DTu1nhvkkQw9FMR

https://drive.google.com/drive/folders/1DFzUd18L5cMMKHzJrmWXwXwOhdtF_TZH

The following link leads to data/pictures/schematics/etc. I gathered through the years on the subject of tube testers. Almost all was found on the internet so don't expect completely new finds. But I think there's no other place on the internet at the moment where so much can be found at one place:

https://drive.google.com/drive/folders/1ep0Qgl2wqFCD2sZ4Q0Z3tFoaZxcrU7F2

A friend of mine will gift me a hand-built Hi-Fi without tubes, but I all of of them already. The schematic is in attachment, the only variation is that EL34s run with 43% UL taps instead of pure pentode (so of course the choke will work on the PI and driver only).

It is around 15 years old, and built based on this article, with some variations:
PP2010 - Hi-End Push Pull Amplifier

First of all I have one question: layout is same for both monoblocks (they are not mirrored), wiring is same, but whilst one is perfect, the other one needed a 50 kHz lowpass on the PI because of some autooscillations out of the audio band. Can it be due to some differences on the parameters of the output transformers?

Then I would like to ask you if you agree on some mod to be done this winter, after a long period listening to it as is:

The first one is to move the coupling caps before the 12AT7, to apply the bias to theirs grids and DC couple them to the EL34s and to be able to drive them into AB2 squeezing a bit more watts.
To do so I will rectify full bridge the 40-0-40V winding and the 12AT7 will be connected to that negative rail (around -112V) through the resistors (that could become a CCS indeed), while anode will be kept positive of course.

The other one is to apply shunt feedback to the EL34s, that in this case I would apply by connecting the plates of the EL34s and the 12AX7 with a resistor (I guess the value will be around 1 to 2.2 MOhm). Then I'll try it with and without GNFB.

If you see something better that can be done to it, I'll be pleased to try.

Thank you all in advance.

So I was thinking of getting an oscilloscope for the hobby (similar to the tektronic ones I used when I was studying computer electronics back in college) and came across the "new" generation of oscilloscopes.

feedback on these?

Thanks

EDIT:

• I am looking at the $200-$300 USD range.
• not sure what is digital audio (the frequency range) but will be use to "debug" the various DIY projects (2 channel ones). I don't think I'll be building a DAC.