Hi Folks, I'm looking for the schematics of the Quad 12L Studio Active monitor. One of mine has developed an intermittent crackling noise, that I want to track down and fix. I've posted this in the chip amp section, as I know these things use a pair of chip amps! I can probably reverse engineer them, and will if necessary, but thought I'd see if I can save myself the trouble... Thanks in advance! Dave

I am having trouble with my Peerless SLS 8 for my 3 way. I have taken actual theile small parameters using REW. When I enter those into WINISD I always end up with a weird hump. Stock parameters for the Peerless SLS 8 is dead flat. I will show the parameters, the graphs, and the box.

Does someone know of anything I can do to fix this? I planned on crossing it over at 300hz but I fear I will end up with an odd dip between 80-200 hz.
Stock line is red, actual measured theile paramters is pink.

I am making progress fixing and "calibrating" this classic calibrator.


Backstory:
(or skip down to the maroon coloured text to see my concerns/issues}

I am attempting to rehab a 70's FM tuner (Luxman t110u).
So, I found this dusty Sound Technology ST1000A at my local surplus dealer - no fuse holder, loose switches, unknown functionality.... $100.
At my bench, I fixed the fuse and decided to replace the main PSU filter caps. Good thing, because one of them was bad and had turned into a wayward resistor.
(they were 1500uf each rail, but I went for 2000uf each.)


Then, through an ammeter, I plugged it in to my variable AC transformer, flipped the ST1000a power switch and slowly turned the voltage up to 120v ...keeping a close eye that the ammeter did not spike.
All seemed ok, and it showed signs of life.
After a long sleep, it curiously opened it's dusty eyes.

I cleaned and lubed the rotary switches. The carbon pots did not seem to need attention. The meter reacted as if it was new.
I began to replace the smaller axial electrolytic caps on the internal board, but every cap I removed tested like new, so I stopped replacing them, for now. Those old Sprague 30D types seem pretty robust !
This must be an early unit, because it includes Opt, M-2, but not with the typical 1k/400hz switch.
Instead, it has 4k/400hz. Curious.



The manual/service guide is easily found online, and here...... http://www.stancurtis.com/soundtech.htm
An article on "updating/upgrading" the ST1000a is here..... http://www.ham-radio.com/k6sti/st-1000a.htm

Following the adjustments outlined the manual, the ST1000a was close to specs, but everything needed a little tweaking to become spot-on.
I performed one upgrade from the above article, to lower the distortion of the internal wein-bridge oscillator (added two resistors and a cap).
Using my QA403 audio distortion analyzer, before the mod :
3862 Hz (4 kHz) = .027 %THD
393 Hz (400 Hz) = .017 %THD
...after the mod:
3862 Hz (4 kHz) = .0008 %THD
393 Hz (400 Hz) = .0006 %THD

Other adjustment steps from the manual:

152 kHz/19 kHz Crystal oscillator adj.... (C20) adjusted to within 10hz, good.

R/L Gain Balance (38kHz Carrier Suppression) (R1, R7) One trim pot minimizes the 38khz ripple from the upper half of the (sine) waveform, another trimmer does the same to the lower half of the waveform. I think I did it correctly, making both halves of the sinusoidal wave show as little ripple as possible. I can still see a little ripple, but just barely.

DC balance. (R19) Trim to get lowest DC millivolts (less than 20mV) I trimmed to 5mV.

Mono/Stereo Sub-channel Separation. (R35, R38) Here, the guide is confusing. I don't feel confident that I am adjusting correctly.. or to what is wanted.
The drawings are rather vague ?

I tried Method A and Method B.
Method A, I think I'm trying to get the flattest line across the center ?
Method B, I think I'm trying to get the "cusps" close, but not touching ?
Here are my adjustments, and a pic of the overload-preventing clipping diodes, per the manual instructions:




FM Modulator Linearity. (trimmer R52) In this step, I do not have the gear shown in the drawing.
HP 5210a Discriminator
HP 10534a Double Balanced Mixer (50k to 150mHz)



The 5210a discriminator...guessing this gives you the difference between two frequencies ??
I think I can do that with my counters, including phase differences ?

The HP 10534a passive mixer....I have one of these (Clarke Hess "active" mixer) but I'm not sure if will work, or if it has enough bandwidth , I've been looking for it's rare manual.


Modulator Level (trimmers R47, R95) This is to be done after the above Linearity step, so I can't proceed before the Linearity adjustment.
The manual gives a method using an accurate Standard Generator, OR a method for using a Discriminator.

Internal Oscillator (distortion adjustment, R105, R95) I did that, as noted earlier.
Pilot Phase. (R93) not adjusted yet.
L/R Balance (R118) not adjusted yet.
RF Stereo Separation (C16 trimmer) not adjusted yet.

END OF ADJUSTMENTS.

BTW, I built the "ST Model 100" 50 ohm to 300 ohm adapter, as noted from the links above....

A buddy has a pair of VTL Compact 100 Monoblocks (circa 1988) that have performed well, He recently retubed & reset bias with good initial results. Several weeks later one of the pair began blowing mains fuse. I have SS experience but am a newbie at tubes - my first thought given the age was to replace electrolytic capacitors & check tube associated resistors as well as solder joints & socket to tube pin contact. Am I on the right track or are there other obvious items - also if anyone has a schematic that would be very helpful. Thanks!😉

The crossover for Dennis Murphy’s CAOW1 2-way speaker design calls for a 0.06 mH inductor with a 0.10 ohm DCR. In his write-up Dennis indicates “You will probably have to order a 0.10 mH inductor and unwind a little less than half of the wire. The value is not critical.”

Dennis Murphy's CAOW1

Dennis is correct so I have some questions about how to arrive at 0.06mH from a 0.10mH inductor, or at least close enough to work:

1. Can I weigh the coil on a digital scale then unwind and remove material bit-by-bit until the coil weighs 60% of the original value? The only thing I would be measuring here is weight of the coil.

2. Would it be better to purchase an LCR meter to measure inductance as I unwind, or is this overkill considering Dennis’ saying the value is not critical?

3. In general, do most people verify the accuracy of other crossover components or trust the manufacturer’s values? If most verify other components I may get an LCR meter to check resistors and capacitors in addition to getting really close with the inductor.

Peak LCR Meter

Thanks in advance for your advice!

Someone know , when could we buy some Textreme drivers from SBACOUSTICS ?

Just joined. pcjthe1 because in the UK there are LOTS of Joneses. Semi-retired engineer of 77 years young. Electronics, Mech Eng and computers my main interests/work area plus DIY on house and cars. Main car DIY is on "Bagheera" the mighty V12 Jaguar Sovereign series 3 saloon of1988 vintage.

Hey MiniDSP. Can you please help me with a failed login? Please send a pm and happy to discuss offline. Thanks! I can't even look at the website to get your contact details because your human-check locked me out!

Thanks

SOLD
A set of XRK Audio BTSB THT buffer board for sale.
A very convenient front end board with good connectivity flexibility, and gain selection by means of dip switches.
More details are here :
https://www.diyaudio.com/community/threads/btsb-buffer-se-bal-to-se-bal-buffer-gb.358142/
My board happens to be the version with a slight error as mentioned in the thread above.
Details of the error here :
https://www.diyaudio.com/community/...o-se-bal-buffer-gb.358142/page-3#post-6330962
A simple change of resistor position would correct this error, and this correction has been done on the board i am selling.
I used an off board bipolar psu for this board and hence did not populate the Murata isolated DCDC. Wires has been jumpered to the connector for +/-15Vdc inputs.

I will also throw in a set of discrete diamond buffer i received from the giveaway from XRK Audio. The default giveaway boards has 'wrong' led on them. I have changed to the 'correct' led part recommended by XRK Audio. They have been tested and working properly. I paid shipping from US to Singapore for these boards. Details of board here:
https://www.diyaudio.com/community/threads/xmas-diamond-buffer-giveaway.405895/
https://www.diyaudio.com/community/threads/jhoflands-diamond-buffer.401231/#post-7522644


The set of BTSB + Diamond buffers + shipping registered & tracking = 95 USD
Paypal FF Only please.

.. myself.

Hi, been on here for many years and decided to join.

I’ve built and have been working on a number of projects.

Pair of SEAS Prestige 27TBCD/GB-DXT H1499-06 Tweeter. Gently used, work great. $200 + $10 shipping.

SOLD Pair of SEAS W22EX001 8ohm woofers. 8" magnesium cones. Used, not abused. Not original boxes but will be well packaged.

All were used in an active XO 2 way config.

General consensus from what I read is that a straight log pot of good quality is better than any shunt arrangement. So no doubt several replies will confirm this. Downside is that good quality pots, especially stepped attenuators, are expensive.

But supposing, in the interests of economy, you did construct a shunt control for a valve amp or preamp, what is the best you can do? Here we assume a typical DAC input of low output impedance which would be happy into 10K. So I'm assuming that theoretically the shunt resistor should be 10K or more, but please dispute this.

I've made an experimental external box to try out different resistor values. Shunt resistors for first trial are old style black Holco 1W. Pot is 50K log chi-fi Alps. This feeds an amp with a 100K resistor to ground on the input. Results....

38K shunt - law is fine but too much attenuation of the signal
10K shunt - louder and the law is actually quite good.

These are very audibly inferior to a simple 100K Holco input resistor to ground and volume control in software on my Mac Pro with lossless tracks in iTunes.

Please suggest anything that will give better results......

Hello,

I have few caps

Audyn QS6, Qtext4​

not tested by anyone yet, no reviews at all conducted.
I'm looking for somebody with the expertise and experience willing to do tests and share his impressions.
I'll supply the caps, but based on latest Canadian postage rates, shipping is quite unaffordable/reasonable in comparison to the cost of the caps and else..
Thus I'm looking for somebody in Calgary ( a long shot) and surrounds in order to avoid the shipping charges.
Any other suggestions, please?
Thx

Dear Sir,


My friend has a MSB DAC which has RJ45 input called I2S pro. DAC feedback the clock to MSB transport. for the rest of the pin should be I2S signal.

Any one know how to connect the another I2S device to MSB I2S pro.

For example, I have philips CDM4 transport which has HDMI and RJ45.


If I know the pin assignment of MSB DAC RJ45. I can make the connection to MSB DAC

For sale a Pair of the best 15" woofer from Audiotechnology

15 F 102 25 10 KAP Woofer​

price 1206 euro pair

best Bjarne

The beauty of destroying lightbulbs and tubes in slow motion

I worked on this film for over a year, with new ideas coming up over time. The slow-motions were recorded with two older Samsung S9 and S10 smartphones, which offer a video function for this. The cameras only record for a period of 0.2s and 0.4s, whereby the triggering of the shutter release is done by movement in the image. Almost 1000 frames per second are recorded (960fps). The sequence is correspondingly short. Despite this limitation, I have lost practically no recording, which is irretrievable in scenes with more material use, such as with the picture tubes. Someone will ask, "Why is it still running so fast, slow motion has to run even slower?" The challenge was to deliver a maximum result with this minimal amount of equipment. On the other hand, the film consists of a lot of individual shots, all of which I want to show. If you were to shoot them with much more time dilation, the film would not last 7 minutes, but maybe half an hour. My intention was to put the dynamics and action in the foreground - you should see how it shreds! 😀

Login to view embedded media

Hello,

I'm experiencing a peculiar issue with my audio setup and would appreciate any insights or suggestions you might have regarding the TSA1701 DSP. Here's the situation:

I have two 15-inch subwoofers that are functioning correctly. However, when I connect a third amplifier to the system, there's no sound output—only a loud cracking noise (as shown in a video I have). I've checked to see if the DSP (Digital Signal Processor) is the problem, but the same issue occurs with a second TSA1701 DSP unit.

The problem does not seem to be related to the tweeter or the third amplifier. It arises as soon as I plug the jack into LineOut2. If I only have LineOut2 connected with two loads and then add the third load to LineOut1, the same issue occurs.

I've also ruled out the possibility of the DSP's USB power supply being too weak, as I've tried powering it with 10V directly at the socket. All individual components (2 subwoofers, 1 tweeter, 3 amplifiers) work fine on their own, but the DSP starts acting up as soon as both jacks are plugged in.

Additionally, the cracking noise gets louder when I increase the input volume.

I also tried connecting the tweeter to one of the subwoofer amplifiers, and then one subwoofer and the tweeter played perfectly. However, when I added the second subwoofer, the cracking noise returned.

One thing i thought of, is that because the DSP does have 2 3.5mm output jacks, i used 2 3.5 to RCA Cables. Because i only need one output of the second cable i just cut of the other line. Could it be possible that the error is resulting becuase of this? Should i short the wire i cut, or solder a resistor in between?

Is there any other setting or property of the DSP i have to take care of?

Thank you in advance!

My Setup:
TinySine TSA1701
Hypex SMPS400A400
3* IRS2092 500W ClassD Amp
2* the box 15LB075-UW4 15"
1* Master Audio DR8
t.mix 201 USB Play for Audio Input

Hi, I'm Thomas from Austria.
Last year I graduated from a technical college (HTL) in the branch Electrical Engineering - Smart Systems. Starting this fall, I will be studying computer science at the Vienna University of Technology.
Already during my time at HTL we created some DIY audio projects, among other things by designing and producing our own Class-D amplifier boards, and then used them in a portable active speaker.

I am looking forward to participating in some of your contributions and hope for your help in some areas.

Thanks, Thomas!

https://www.diodes.com/assets/Datasheets/ZHB6792.pdf
Theres no marking on it ,at least I dont se any..

Greetings. Attempted to repair my XLS-402 which had very low output on one channel. In a moment of brain fade I attempted to clip my scope ground to one of the driver transistor (MJE15032/033) heatsinks, thinking it would be 0V but instead got a wakeup call with a bang and a flash. I was aware the output transistor heatsinks were live I just stupidly didn't test the smaller heatsinks first before looking for a convenient scope ground. Replaced all the MJE but no output at all in either channel now. There is 95VDC on the output heatsinks but nothing on the driver sinks, I assume there was before given the fireworks from shorting it out. Schematic shows these are all connected together, any thoughts out there on why this might be the case?

Cheers

I have a VX150 here. I used to have three of them years ago but sold them. This one had the VCA input cards.

I have recapped this unit as the caps on the main board were going high esr and low capacitance. I stupidly put in 10uF cap in the feedback path on each channel! Of course when I tested frequency response it was down 3db at 20Hz! Anyway, I installed 100uf and then was fine.

I'm surprised how bad the VCA input cards cripple the amplifier. Distortion figures were not that good. 0.05% at 1Khz mid power. This climbed to a very bad 4% at 30Khz!! Also I had to drive it with 5v to get full output! I pulled out the VCA boards and jumpered the links and now much better. Distortion at 1Khz is 0.0045% mid power and the same at 20Khz. Also no hiss even with headphones.

Bias, DC offset and CMR adjusted to spec.

Would the sound of the QUAD 606 benefits from an external PSU like what the PSX did to Cyrus? I f the answer is yes, my next question is: what size should the external transformer be, 1000VA? 1500VA?

The Cyrus PSX has a 500VA transformer, which is ~2.8 times that of the built-in transformer inside the Cyrus amplifier.

Has anyone try that?

This is why I don't like working on subwoofer amplifiers: I was working on a John Bowers Active 1 today and was not aware that the output neutral speaker line sits at -40VDC.

Usually with some McIntosh amplifiers, I have to ground the analyzer to stop the relays from clicking periodically, and I thought this was the case with this subwoofer amplifier.

It blew out something, possibly a fusible link inside my UPV audio analyzer. Now that input no longer grounds when I set analyze to 'grounded' in the menu.

I'm looking for a schematic of the input circuitry to find out where this fuse is located so I can replace as needed. At least I hope it is just a fuse and nothing more involved.

Having collected some promising drivers to cover from 16Hz to 20kHz, now some serious sims. Please bear in mind that due to rural regional location 1400km from Sydney, getting heavier items delivered has been problematic. A lot of times, vendors just notify with an out of stock with funds returned message

SBA and DS18 are the two brands that do send the deliveries and prices are affordable and here are some DS19 based sims including a couple of wildcards. Open to driver suggestions

This project is an attempt at shoehorning the most hardware into a cab with space constraints. Living in a tiny home makes one a bit conscious of volumes and space use. A 1cm increase in one dimension can potentially mean many more new litres. This audio project is on pocket money, channelling tobacco money to audio and recreational in nature, although I would mind making up some bespoke type parts with the digital studio and handcraft for folks when the tobacco runs out 🙂

A 50g pouch of tobacco costs over AUD $100 and the bwoy is broke after buying so much audio interest items 😀

Uses
Home cinema, when not working
Small DJ/karaoke gigs
Practice PA for a small student ensemble running synth pickups via Roland Aria MX-1 digital mixer, FL Studio with Akai FIRE control surface, Roland DJ-202 digital mixer with TR -Drums and sequencer, Roland JDXI synth that can be played with an instrument via line or mic, Yamaha MG12XU console and an electric bass guitar/double bass. Running school material through the EDM gear as extracurricular activity

SOR
Loudest full spectrum achievable within space constraints
Ability to run a flat response or Eq (onboard or external)
Electronic filters built into the system (onboard)
HT processing (onboard DTS,AC3)
Have the refining touch of bypassing the internal class d amp for the HF section and engaging an external tube amp for the tops when used at home

Config
A phantom centre based 4.1 channel satellite and sub config is appealing for not having heavy boxes up in the air. If a single LF section tests sufficient, then the 4.1 config has the added bonus of being able to fly with for tours in the home country by swapping out with a higher tuned, smaller sub cab. If a single sub is not sufficient, the cabs will be built as 3-ways with each cab featuring an HF and LF section for 4x cabs total

Primary use is HT with mostly music video and concert recording from Rototom Sunsplash type YouTube channels, streaming sites such a Netflix,. The HF sections will run of 2x 10w+10w EL43 tube power amps and a tube stage or Pass H2 inserted in the LF path. Room is 3m x 6m with three walls that can open up. This space is the open deck of a 6m custom catamaran. A bit like a pontoon boat, but not the tacky aluminium types of things that are very popular. Ours are a pair of hulls in HDPE filled with survey grade foam and tiki style wooden cosmetic finish. The walls are privacy/weather screens in wood strip and plexiglass. This vessel is under currently under construction as home DIY. It's getting built to Au maritime survey and will be rented out when not being used by us. Setting up for a working retirement with this and two other vessels, a 3.5m centre console semi GEV sports fisher and a 3.5m beach cat to deck boat conversion with deck chairs and human/electric hybrid propulsion. The location is Hervey Bay so no issues with noise pollution with being easily able to put double-digit kilometres to the next soul

Secondary use is as the mentioned PA system, with back to back pair on either side and out from the desk. To fire at the desk, any performing floor space between these wide monitors and the desk, and well to fire away from this area. School hall or someone's porch or lawn for lil DJ/karaoke type gigs. Of course the desk will also have nearfield monitors too. These are from the 'Exploring the ZR6.4D' thread in subwoofers

Our Roland and Akai pro gear will be housed in a travel case to be easily relocated to home or houseboat, as well as away trips. All the amp modules and DSP processing to be built in the speaker cabs except the tube amps which will be installed in the houseboat

So as some wind down from looking after the baby and running around all day for the family and renovations and boat builds, let's have some fun blowing up stubborn high excursion subs by winding up the power and beating up the Iron Law by taking it up to the melting point 😀

These are the drivers in contention at the moment. These have some means of environmental protection in a marine environment. Other suggestions are also very welcome. But please, apple to apples.....ok to use large format systems such as traditional PA for reference comparisons but always ask the question on how that favoured PA driver or hi-fi brand would go in these size constraints vs the SPL/response requirements. If one's fav 18" with 108dB sensitivity cant meet the SOR than the matter of fact is that it is just not good enough for the job. If a cheap and apparently looked down upon car audio gear can hit the numbers in the constraints, then they are the better drivers on the day

Constraints
10L internal is the max allowable for each driver volume for the HF sections
40L internal is the max for the LF section/sections
Smaller volumes than that would be even better

Driver pool HF
PRO-ZT69
ZXi-354
Nilspec 6.5" FR

Driver pool LF
ZR12.4D
10" DVC Unobtantium (almost half the price of the ZR12.4D)
12" DVC Wildcard, not yet acquired ($50 cheaper than the ZR12.4D)
SLC12S, not yet acquired (half the price of the ZR12.4D)
SLC10S "" (less than half price of the ZR12.4D)
SLC8S "" (well under AUD $100)
ZR6.4D, the super stubborn, super low sensitivity driver from the failed Cub Sandwich project as the near filed woofers and to compare just to get a feel of the difference in loudness levels

A side project will be to use the ZXi-354 will be used with ones of the LF drivers at an attempt at the 'high SPL. Full spectrum, 2-way' thing just out of interest

Another side project is getting one of the coaxials into a single format cab with the Unobtanium driver as a 3-way for simple travel and mixing down stereo sources to mono for use tested against the same driver with a pair of stereo ZXi-354 or 3" Tang bands again in a single box. If the ability to present a solid stereo image cannot be obtained from that, then the single coax will be kept

A single cab 3-way is needed to be in use by August, but the full development is not a rush thing and more for fun. I must mention @weltersys for helping me learn some of his lifetime of knowledge, so I may pursue this with valid data and calculations and as well for picking up on problem areas. Also @GM, Great Man, thanks for not beating around the bush and allowing me the confidence to work towards unfamiliar high SPL numbers with his direct anecdote and reflections with hands on SPL taking in his areas of use. Very grateful to these two guys

Hello,

I am new to the forum and joined looking for some help.
I own a set of Denon PMA-700V and Denon DCD 1520 which have been working well until two years ago.

The Denon Amp Balance potentiometer started failing and now needs replacement It is a 250K Pot.
The CD player Pickup Lens (KSS-151A) afiled and also needs replacement, preferably the whole CD Tray assembly

Is there anyone who can guide me to a source for these (Very) rare Denon spare parts?

Thanks and Regards,

I always assumed diyaudio.com and diymobileaudio.com were related. Is diymobileaudio.com it's own independent being?

I'm considering a Car Audio build, but don't want to deal with duplicate posts.

Hi all
I found this site after my Squeezebox Duet controller stopped working 100%. I had previously had two Duet receivers fail, so I had switched to using a WiiM Mini. Much to my delight, the Duet controller continued to work with this, accessing the music stored on my NAS with Logitech Media Server running on my PC (I don't use any other streaming service). But recently, when I came back to using the system as set up, I got a "problem connecting" message: the controller could no longer connect with either my NAS or to my PC - "make sure your computer is turned on and that LMS is currently running". Well, it is (I am writing from it!) and LMS is running. On checking the diagnostics tab on LMS, I found as shown below: one of the ports had failed, while the mysqueezebox.com site was also non-functional. Further enquiry showed that it had been taken down by Logitech. I can still control the WiiM via my iPhone, but I am wondering if I can somehow resurrect the Duet controller, whose clock continues to work! and whose UI I really like! I don't understand ports very well. Can someone please advise? Thanks

I have been handed a NAD2200pe (serial - A 60900xxx)
It was fully recapped before it came into my hands.
I have no knowledge of its history as the current owner that handed it to me, recently bought it second hand himself.
I've fixed a lot of bad solder joints.

The below applies to both channels;
I can set the dc offsets easily to under 1mv.
Both bias's however refuses to budge from 0.1mv and the unit stays cold even after several hours of idle.
The trimpots are fine.

Any pointers would be greatly appreciated.

Hi Folks
I have a Boston Acoustics Soundware S 5.1 speaker system. I am facing the problem of low output on my Sub in spite of keeping gain at max i can barely feel/hear the sub when playing heavy bass content audio.

The subwoofer included in this package is a 10-inch downward firing 200W RMS (Peak power of 300W) sub. Many years back this subwoofer had failed (power supply board had burnt out) and I had taken it to an authorized service center for repair. Sure, enough they did repair it and i thought it was fine, though i did complain about low Sub output. What i did not realize was that they had replaced the power supply board of my sub with one from Boston Acoustic Soundware XS model. The XS series has a 100W RMS sub. I found all this out because the sub failed again recently and when i opened it to fix it realized the board had changed. I little search on the net i realized the swapped in board was from XS model. The problem now was a burnt zener and a dry solder on a diode. Replaced the Zener and reflowed the dry solder and problem was fixed, and Sub was alive. But output level seemed to have dropped drastically.

Could the low output on my sub be because of the under-capacity Power supply board?

There are two outputs from the power supply board one for preamp and one for amp. Power for preamp/dsp given thru a 3 pin connection -20V:0:+20V and power for amp given thru a 3 pin connection -32V:0:+32V. Assuming the low sub output is because of lower capacity SMPS board I would like to replace this power supply board with a beefier one in line with the original spec, but I don't have the original board, nor can i find the service manual for the Boston Acoustic Soundware S.

1. So does anyone have the service manual or schematic of the Boston Acoustic Soundware S (not the XS i have the manuals for that).
2. Does anyone know what voltage should be given to the amplifier section in the Boston Acoustic Soundware S Sub. I have to assume it is about 45V. I am assuming this because if i look at the driver Amp board the capacitor right next to the power input is rated at 63V. So I am assuming that the rated DC Input would be 45-50V.

Any other possible reason for the low sub output (one more suggestion is heard was to replace all the caps in the amp, while i can do this for the SMPS board i dont think i can do it for the preamp/DSP/amp board as there is so much glue used on that board to stick it to the case that any attempt to free it from the case will damage the board

Any advice would be appreciated. Thanks

During next weeks will offer hundreds items for sale , all prices in US$ +ship . Shipping is costly , small items lower than 1kg is about $20.us , since I get a lot for sale ; grouping your purchase will help to reduce shipping cost . Buyer: all details, payment and shipping by PM please .

And don't ask me specific item , I just open box and list it ; so come see my ad time by time this way you will miss nothing . All items by number for reference , missing number are sold item , and letter after number is modification.

Sold1 A ------- USSA5 Fab power amp with quality components , 2013/313 come here on diy from a trusted member : Calvin , for out one of best pair ALF16N/ALF16P ; there is no input capacitor on board cause it is crutial to use top quality (all info pass by) but your preamp must be very low dc out .
I didn't solder driver and out depending of your heatsink choice . Presently RV1b/RV2b are 110ohm , up to you to find 1a/2a with pot ajustment.
Only one pair remain : Price is $200./pair , may offer power supply dual board (X2) with 8x 47,000uF and ixys 12A/1200v diode (8936/SOLD/B]

2 ------ SALAS DCB1 versions : all original genuine parts , no heat sink (too shipping costly) 39 ohm resistor for testing evidently you will use much lower with sink, mine on 24/7/4 years now with 4.7 ohm 10w around 54C on sink , the best of my 50 years in audio but with top cable/casing /transformer /L pad volume control/ and WBT RCA. The one with heat sink come with 9.1ohm 3w . All unit with very low dc offset.
Price : mezmerize blue $120. black $110. (( hypnotize with heatsink $80. SOLD ))(( without $70. also SOLD)) (8939)

3--SOLD------ Jung/Childress TDA1541A output board (TAA article 87/88 for Philips 650) to replace cheap 8 pins chip out in Philips/Magnavox/Hafler/Quad/Rotel/Revox/Hafler etc,/etc. . One with all possible wiring and regulators , the other one with 4 oz teflon pc board and Wonder 8.2uF cap. TDA1541 are new not remove from board .
Ready to use one$85. the teflon board one $90. (8942/8944) SOLD



5--------SOLD- Kester solder (all info on pic) great to solder PC board and as good as many after market solder if board is clean , and same for wire (from transistors, capacitors, resistors etc), with this .4mm there is no extra solder (to me the less the better for sound) on board . You need to solder bigger parts ! no problems ,have look on pic : one row of wire for pc , 2 row good for 18 awg, 3 row up to 14 awg and 4 row good for anything . Flux at 3.3% is very active and this the reason why mutiple row are effective... but please ,please, please don't twist this solder with bare hands... use thin glooves, 12 to 16 in. is good lenght to work.
Last but not least ! all those new circuit board without pb are not easy to work when come time to replace parts... use few drop of this solder will greatly help .
Price $28.per roll, $75. for 3 rolls. SOLD ALL SOLD

7A--- ALL SOLD---- of my offer JVC31B of 5 unit , 4 are sold 1 remain( now, shipping whole unit is too costly , so I offer partsout : laser mech. with remote $85. price postpaid is valid USA conus or Canada . Last one ! last chance (8995) ALL SOLD

8---------Castle Stirling 16 ohm woofer brand new 4x $120. 8x $200. (4 003)

9-------- Vishay S102K 1K $3.00 each , 24pcs at $2.80 ea 48pcs at $2.60 and $250. /100pcs (8763)

10-------2x brand new tone control board HK 600 $50. without knob $44. sold many for pot (out of production since long time and cost non sense $$$ on bay . (7331)
12------- 2x C540H (see date on it) Price $25.pair (8005)

13------- 3x OPA 549T $45. (8008)


14-----4x fet dual power 2x ALF16N + 2x ALF16P brand new from element 14 some years ago . Out of production since few years $95.
(8755)
16-----2x sealed power supply +/- 15vdc ; same as used by ML on early preamp model $30. pair (1 002)

17------4x Vishay 1280G 5k/ .75w /15T , one of best to ajust bais 4pcs $40. (8100)
18------Acoustat 2+2 $1300. vg condition ; I am 60 miles away from north VT/NY far east

19------Soldering desoldering station 2 Pace gun , 3 x soldering/desoldering 60w and one 70w , new heater + few other parts
the only need is a small compressor, a bargain at $240. (8977 - 8979 -- 8982 )

20------.1uF 400v VG sound 50pcs $50. (8033)

22A-----shigaclone black MK2 , brand new boxed since may be around 8/10 years . Just open to take pic, I guessit's good for experimented diy $150.
new offer ! at this price the MK2 black will come with new 16pin drive and JVC original puck .
(9049--9070---9080) pic will comeASAP

Here some more offer ; don`t miss 1A+46 a real bargain offer

SOLD 1A + 46-------- FAB USSA 5 class A power amp; description here at post 1A:
1 A -------- USSA5 Fab power amp with quality components , 2013/313 come here on diy from a trusted member : Calvin , for out one of best pair ALF16N/ALF16P ; there is no input capacitor on board cause it is crutial to use top quality (all info pass by) but your preamp must be very low dc out .
I didn't solder driver and out depending of your heatsink choice . Presently RV1b/RV2b are 110ohm , up to you to find 1a/2a with pot ajustment.
Only one pair remain : Price is $200./pair
+ no 46--------FAB USSAP preamp built with quality parts . Total 1A+46 only $230. + shipping 660gr boxed so able to up 340gr parts for free shipping, pic 9220-9213-9214 SOLD

47----------- Dynaudio D28 pair (8ohm) in exc condition $140.pair , shipping 1.35kg boxed . Pic 9225/9226

48---------- Dynaudio 15W75 pair need new rubber (tear); perfect if you do the job yourself or you know someone able to do at reasonnable price ; $60./pair 2.7kg boxed

SOLD 49---------- 6X BB OPA627AP $60. SOLD

Have look the following: https://www.diyaudio.com/community/threads/50-years-diy-must-reduce.409885/#post-7678070
https://www.diyaudio.com/community/threads/50-years-diy-must-reduce-suite.411197/#post-7677571

50----- IC offer ; all new and genuine (from 85/99 Mouser/Digikey) , price for each , few are used and well indicated . No 50 only a partial offer ,will follow with no 51 /52/53 if sale are good 😉 . And please ! don't ask me for less than $50. order . Pic 9233/9235
6x BB opa 2134 $3.50 ea
2x OP275 $3.50 ea
10x LM 4562 $2.50ea
6x opa134pa $2.00 ea
2x BB opa 2228p $8.00ea
10x AD826an $7.00ea
2x OP249 $3.50ea
4x AD744jn $7.50ea
4x AD 8561 $5.00ea
4x AD 823an $7.50ea
3x BB opa 2277 $7.00 ea
2x OP27 $2.50ea
2x OP 275 $2.50

SOIC
4x AD825 $8.50ea
2x AD8620 $12.ea
4x AD8610 $6.50ea
2x AD8512 $4.00ea
2x AD8529 $2.00ea
2x OP2177 $3.00ea
2x LM6172 $5.00ea
2x LMH6626ma $4.00ea

]Here an idea of shipping cost ,all in US fund : USA = 250gr $14. 500gr $20 1kg $25 2kg $30 (please note only $5. for the last kg); for Canada same but in cdn fund
Europe : 250gr $14. 500gr $25. 1kg $45. (sea mail $24) 2kg $65 (sea mail $34.) over 2kg , sea mail not a choice ! Don't forget I need 100/125gr for shipping box .

23-------------16x MPSU10 4x MPSU56 2x MPSU10 2x MPSU60 9 MPSU 07 all new , genuine from around 1990 $120./33pcs (pic 9118)

24------------8x new Mundorf 47,000 uF 25 volt all tested within 10 % $100. 1kg (9115)

25------------12x new Mundorf 33,000uF 25volt all tested within 2% $120. 800g (9092)

27-----------SALE PENDING SOLD 2x brand new Mundorf 6.8uF 800ac/1200dc supreme silver/gold $160./pair, absolute great sound at reasonnable price ,but long burning time=200hrs.(9114) [B o9]SOLD SALE PENDING[/B]

28------------4x brand new Audyn true copper .33uF 630v $90. per pair and 120gr (9114)

29a------------SOLD 2x new Audyn true copper .1 uF 630v $60./pair 50gr (9114) SOLD

30a---------2xSOLD 2x remain used Mundorf 1uF supreme silver/oil 800ac/1200dc $90./pair (wire cut but very usable to solder on board) (9114)

31------------4x used (very little ) Nichicon KG Super Through series ( don't mix with lower price(and sound) similar version but not Super Through $40./pair 500gr (9114)

32----------- 4x new power supply PCB (maintly class A, but fit others) $22./pair (35gr) fit 40mm diam capa (9083)

33------------4x new MrEvil capacitance multiplier power supply PCB (come with 4 LED and J112 transistors each set) $16./2 (9130)

34a------------(12x) only 8 now Elna Audio capa 12,000uF 63v , 35mmdiamX50mm , sell only by 4 unit $35./4 (9122)

35a------------(36x)only24 now Elna 10,000uF 50v (35mmX63mm) ,sell only by 4 unit $9.00/4 (9122)

36a------------(40x) only 28 now Nichicon 12,000uF 50v (30mmX50mm) , sell only by 4 unit $12.00/4 (9124)all sold

37------------SOLD 2x PCM63 , 1x CS 8412 et 1x Tent , all for parts $35. (9132) SOLD

38------------3x new Salas SSLV 1.1 each are 2 regulators+ and one (minus) all boards on pic $35. (9139)

39----------- 1x B1 micro board dual mono , my way to do it . $7.00 each and get lot (genuine , no scrap here) 2SK389 or LSK389 ($12. and $10.) if you need it .
40------------3x Shigaclone pcb (from Tibi here on diyaudio),with all not easy to find IC/transistors +drive 101N 16 pins each set $50. or better
all 3 set + extra set of rare chip (3) for $120. (3set boxed 850gr) (9071 -9077-9079-9074 sorry unable to get clear pic with this last one) all in text .

41------------25x Ero MKC 4uF 200v , 4pcs for $5.00 If you take them all , will ad on few other value same type free . (9054)

42------------3x CDM4/19 pcb without TDA1541; Quad 66/Philips 473 /Hafler ; $12.each with tranformer $15. For shipping pcb without transformer
less than 500gr , 1 without+ one with good for less 1kg , take them all ! just under 2kg (all weight with shipping box) ( 9142)

43-------------1x Arcam Delta power supply $25. (9144)

44-------------1x Arcam Delta (250??) display $35. (9145)

45-------------4x PHL 1280 8ohm in very good condition (list around $120 each) $240./4 (9109)

yy--------------lot more to come 😉

xx----------- https://www.diyaudio.com/community/threads/50-years-diy-must-reduce.409885/#post-7646369

This circuit is a natural variant of subtracting error correction but included in the feedback. Instead of subtracting the error, it divides it by NFB.
https://www.diyaudio.com/community/threads/subtracting-error-correction.408153/post-7578125
An error correcting amp feedback only the error found by the difference of the input and the weighted output. The advantage over the composite type, the power chip receives directly the input signal without extra layer and the opamp functions at very low levels which doesn't require super low distortion opamp.
I should rather say wide band error amp instead of opamp because it must amplify the error without integrating it. The difference the error amp sees, is the same what the power amp sees, as the power chips are integrators in open loop, if the error amp also integrates the same input, it will become back an image of the output signal. To keep at high gain all the audio band, it needs 2 pole compensation for stability.
This type of amps have two independent stability character, the error feedback loop and the error correction frequency. If higher frequencies than the power chip are asked to get corrected, the chip amp will decrease its phase margin, this why the error amp receives the input via a low pass filter.

I use the AD829 wide band opamp which can have its gain bandwith adjusted. This amp doesn't need servo as the error receives the DC component of the output without attenuation. The slight offset can be adjusted by the opamp offset adjust, not implemented on the model, so I adjusted by R7.
The LM3886 has OLG@20khz of 50db. With 26db CLG, only 24db NFB is left. With this error corrector 80-100db is possible.



The origin of Modulus86 from Mr Evil posted in 13 11 2004.
Thread 'Unnamed feedback method explored.' https://www.diyaudio.com/community/threads/unnamed-feedback-method-explored.45662/

Hello,
I do have some speakers I play with. The Crossovers are outside, same channel from the amp, speaker switch.
Main capacitors, 3.3uF (second order) are on the board, additional/bypass capacitors are connected via alligator/wires clips.
Does the length of wires affect the influence of the smaller capacitors to the main ones?
(Longer travel, slow speed of the electrones, late arrival at the main capacitor)
Practically, adding parallel capacitor upto 50% value of the main cap does not produce noticeable sound changes.
It seems to me, in cases the capacitors are soldered, the sound changes (as to be expected). Or it is result of imagination.
Thx

I received this amp about a week ago and noticed that the bass was not as tight and coherent as I thought it should be.

Anyway, I spent hours today trying to install the new caps only to find out that the factory caps are tamper proof, and cannot be removed by any conventional means as the fasteners are cemented together.

I want to possibly attach a set of 18,000uf 75v caps to the originals for now if there are no issues in doing so.

My other issue is that the legs on the ceramic snubber cap for the rectifier failed so it is no longer attached. It is a .1uf Z5U @ 20% (M). I have no idea what the minimum voltage should be rated at for this amp.

There is a post from @chris mielke in the ba-3 thread that talks about too much gain from the ba-3. My question is, how does too much or too little gain affect the sound? Does it mean the sound coming out of the speakers has too much influence from the source and pre-amp and not enough from the amp? Or is it just as simple as the amp cannot offer the power it has and it doesn‘t have anything to do with the actual sound?

Since most kits I can get from reputable dealers in Germany are thick film, thin film 1% are few and expensive, and MELF or 0.1% flat SMD kits are not listed or frightfully expensive, I just ordered three kits of 1% 0603, 0804, 1206 with 1500 parts each from AliExpress. I was expecting thick film and poor tolerances. When I looked that the little strips, they had been hacked right through resistors, leaving 25 intact resistors in each strip. Some were not great, i.e. the metallization on one side would be three times the width of the one on the other side.

Well, I started with the 1206, tested four different nominal values 2-3 each depending how many fell from the strip when I peeled back the foil. The largest deviation from nominal I found was 0.45%. I then put the resistors on an electronic hot plate set to 82°C, exactly 60°C above RT.

The 300 k resistors had a negative TC between 17 and 38 ppm/K.

The 5k6 and 20k were all between + 12 and +17 ppb/K. The 680 R were at -50 ppm/K. This is thin film territory, even if not precision thin film. Going back to the listing, it said thick film. Can this really be thick film? Operating temperature, TC and rated power were all listed as "standard".Wonder what I got there.

Is there a good way to measure coefficient of voltage? Or maybe I just should measure a resistive divider (e.g. 20 k / 680 R) with a high voltage swing for distortion?

Parts List:

M.2 - 1TB (Type B key)
GeeekPi SSD Storage Expansion Board w/USB 3.1
TransportPi AES
FiFoPi Q7
ReceiverPi DDC
ShieldPi Pro
MonitorPi Pro
Raspberry Pi 4B
PurePi 3.3V/5V

The list above is also my proposed build order. Does it seem correct or should I change the stack? If change is needed, how?
I also would like to know how I can mount this into a case and whether or not I need additional parts like Ians' Linear power module.
My goal is to have it all in a nice case I can put on my desk instead of looking unfinished like an erector set.

Currently I am waiting on the receiverpi and the monitorpi and shieldpi.

Here is a picture of it as it is now. I have since installed the M.2 drive and heatsink.

Looking forward to comments and advice!

- Mario

Reading about anodized aluminum, it has a porous oxide layer.

I’ve seen anodized aluminum in commercial settings take on finger prints and discoloration. Should the surface of custom audio equipment be coated to prevent similar discoloration, or, is it not needed and can it perhaps be cleaned with special solvents?

As promised earlier here :
https://www.diyaudio.com/community/threads/semisouth-goes-dodo-what-now.222098/post-7303805
We are making available our last reserves of SJEP120R100 matched pairs for use in J2/F8.
Please read the above link for details.

On offer are 8 sets of :
1 pair of SJEP120R100, Vgs matched to 40mV at 55°C
1 pair of 2SK3497, Vgs matched to 20mV at 55°C
Registered air mail from HK plus extra insurance (not available to certain countries)
For 1800HKD per set.

Conditions same as previous GBs for Semisouths and 2SK3497s.
https://www.diyaudio.com/community/...r100-curve-tracer-matched-pairs-quads.330916/
https://www.diyaudio.com/community/...-matched-2sk3497-2sj618-quads-at-55-c.397291/

This is even less than the price for a pair of unmatched Semisouths alone offered on ebay.
But we shall leave this open for a few weeks, because of the high values.
And then we also have no more Vgs-matched pairs to offer after this.

In addition, we have, left from the last GB, last 3 sets of curve-tracer-matched SJEP120R100 pairs.
They can be supplied with equally tightly-matched 2SK3497 pairs.
These on request only, as I want them to find good homes and get used in builds.
Please only ask (by PM) if seriously interested to build with them.


Patrick

PS was just told by XACOO that we only have 8 sets left, not 13 sets. My mistake.

Hello everyone,

this is my Nutube Korg B1 preamp with STM32f469i-disco touch screen. And I have been enjoying music with him for more than 3 years. And thanks again Nelson

Hello!
Anyone has used the Classic 1.6 as internal hook up in a loudspeaker?

Any comments?

Thank You!

In the process of making Frugel-Horn Mk3 speakers and some bigger stand mounts to replace small near field computer speakers which have Mark Audio CHN-40 drive units.
Now that the CHN-40 are spare I thought of using them in a 2 way, using them for high frequency duty. This is new to me as I have never made a crossover, please correct me if wrong but the CHN-40 would need to be in its own sealed part of the box. What size woofer would be a good match, low bass is not a problem, sealed box for both okay.
How would I size the volume for the CHN-40 and the woofer to work out the crossover. Sorry for so many questions, big leaning curve compared to single drive unit box and very easy to get wrong.

Does anyone know of a source for Stax 5 pin sockets? I am currently bored in possession of LTSpice and pondering a project for my SR30 electrets...

Hi,

is there anyone aware of some kit (here, in aliexpress or elsewhere) with characteristics similar to the HoloAudio Cyan 2 ?
I read very good reviews of it and I would like to see if I can build myself something similar with a lower budget by building myself.

Thanks

Thank you to Nelson Pass for providing instruction on converting the HK Citation 12 to a mosfet output. I have one sitting on the shelf and this is a project I’ve been wanting to do for fun for awhile. I had a couple of questions and was hoping to get direction.

First, the instructions are older, I’m guessing not, but are there any layout pics that are a little clearer? The schematic is no problem at all though.



This design being older I was thinking I’ll have to substitute parts. The outputs used are IRF-130 which are TO3 packaged MOSFETs. I was thinking I would swap to a TO3p package and use the IRFP240, would that be a good swap for the outputs?

The transistors being used are MPSL01 and MPSL51. What would be a good replacement for these? I have a bunch of 2N5401c and 2N5551c and was thinking maybe those would be appropriate. MPSA92/MPSA42? I have thousands of the 2N5401/2N5551 though so would prefer to use those.

Dan

Found this site while trying to fix my gunked up Yamaha K-420. The counter belt literally turned unto liquid tar. Never seen anything like it. lol

Since i bought durango, i was curious about parameters of its audio. Mainly fr response. First durango i got was with beats system. Sounded boomy. Horrible nasty resonating sound. Just like beats brand headphones.
I returned the car under warranty for other reason. New one i got has premium alpine 9 speaker system. However it sounds the same. Not better.
So i measured fr response with rew.
Next few post are results. Pretty self explanatory.

Ned som PC/Win help as I pectially never use these systems... I'm trying to install gnuplot on my windows machine running on an UTM VM hosted on a macOS M3 laptop.

When I download and try to install gnuplot

gp601-win64-mingw.exe from https://sourceforge.net/projects/gnuplot/files/gnuplot/6.0.1/

I get this message:



This is the spec for my win machine:



Whats not right here?

That it says "system32"?

What did I do wrong?

//

I've never seen schematics of any of his electronics. He had a phono stage, a line stage, and some kind of exotic bandpass filter IIRC?

(if you've got drawings please post them here!)

HI Folks
Does it make sense to buy a used sub woofer. For eg: i am seeing a 9 year old SVS PB1000 available in my area for discount of about 40% on current retail price.

My concern is that isnt it a bit too old for Subwoofer, especially considering the capacitors in the boards would be nearing end of life.

Thanks

Hi all, I built a 24x2 summing mixer with a passive odd/even input with resistors 5,1kΩ as Re, and a NEUMANN V475-2A mixbuss board before the stereo output. The situation is like this. When I connect the built to my audio interface, if I feed the mixer with -18dBFS 1kHz sine test tone to any of the inputs, I get unity level (-18dBFS) back to the DAW when a variable stereo pot (20kB) that I connected as Rg reads 6,2kΩ. I understand that this is correct and as expected, but, if I raise the level by 1 dB (either from the input or the output of the V475 [Rg])I can hear and see that the tone starts to distort. It seems that the headroom of the V475-2A maxes out at -18dBFS. I have also noticed that the pot raises the level of the output until it reaches 15kΩ, but it is not a clear sine after 7kΩ (1-2 dB) over unity gain, unless I compensate for that level raise, from the input. I connected the pins of the xlr out of the summing mixer to an oscilloscope and I saw that the level of the + and – pin has a ½ level difference. If I sweep the input test tone there is no difference from 20Hz up to about 100Hz but for the rest of the spectrum the – pin is about half the amplitude all the way up to 20kHz. When I feed a stereo signal to the mixer and back to the DAW the waveform is asymmetrical ( I took a screenshot from the DAW) if the levels are higher than -18dBFS. In this example levels are -0.5dBFS I/O. I changed all the electrolytics including the ones in the power rails, but nothing changed. I changed the NE5534AN twice with new op-amps, nothing changed. I measure the power supply, voltage and current and is up to specs. If anyone from the community with electronics skills and knowledge on this board - because I don’t have any-, could give me a hint as where I could possibly look for, his/her help would be much appreciated.

Regards,

Nikos Kefaloyannis

Good evening everyone; I have been following your interesting chats for some time; I work in electronics and it is also my favorite hobby. I hope to have some interesting chats with all of you!

Can i get both sq and spl if i go dual 12" sealed 500w vs one one 12" ported 1000w?
I like the ported rumble.
With 2 sealed i will gain more midbass, but can i rescue the rumble? I dont want to go 2 ported because then i loose the sq, plus needs a bigger box.
Car audio
Qts of the subs is 0.3

Has anyone else seen these yet? Dayton is upping their resistor game!
Parts Express - New From Dayton Audio - Resistors

Black Gate FK and N series Capacitor

These are gently used and still lot of life available.

Details are in images, please refer.

I will sell all as a package at very reasonable price of $125 including shipping and PayPal charges.

Shipping to Worldwide at buyer's risk, but it will packed carefully.

Shipping to world will be through INDIA post Registered mail which will take 2-4 weeks.

Thanks for looking.

Back before any of us were born, before Countryman made their op-amp based phase shifter, someone at Hammond designed this and made it work well enough to build into product;



I understand they're pulling current back and forth through the SR 10X transformers windings as controlled by the vibrato oscillator. I understand that those transformers (must be?) mag amps, so when the DC current level is high, they restrict AC from passing through the secondary windings. These days we could use a Vactrol for such a function, but being 1947 or so, they only had "sticks and stones" to work with. (as a former boss once said about our PS design lab)

My question is understanding mag amps are good for things like power supplies, stage lighting, locomotive braking - stuff where you dont care "how it sounds" as the technique introduces a large amount of harmonic distortion, how did they make it work successfully as an audio level control element? I'm pretty sure Hammond would not tolerate the tone of their organ getting all smashed for a little vibrato, even if it beats tremolo.

It cant be that easy. Then why could I not take a cheap 70V line transformer, put some DC / Vibrato frequency AC through the 70V side and render me a "mag-amp" based variable AC attenuator on the speaker side winding? And have it sound just like a variable resistor would? Or, would I need a gapped SE OPT to get close to that ideal? Or - is there truly zero hope of rendering such a thing out of junk you happen to have lying around; you need the custom build transformers Hammond designed for the above circuit? And even then, it only works for miniscule AC currents in the secondary.

I have this three-piece set utilizing the EX-442, MC-101 and TS-108 tuner. I am wanting to go through and freshen them up a bit as I found they were having a problem. Playing them they sound fantastic, but one day I was driving them fairly hard, and I found some popping noises coming from a mid range in a pair of my JBL L7 towers. I happen to have a few pairs of these, so I swapped out the mid range and sure enough it was doing it again. Through some testing and swapping of cables I found the problem to be the amplifier. That’s when I read that, this was likely a mosfet getting noisy.

First off, what is the best method of determining which mosfet is the culprit?

So it used 2SK1058 and 2SJ162 mosfets. I was hoping to get an idea of how good these devices are. Would it be better for me to try to seek out originals and hope that I don’t have to replace too many to eliminate the noise? My other option is to buy all new mosfets from Exicon. It looks like the ECX10N20 and ECX10P20 would be the appropriate replacements for these. If I did go this route, then I would probably buy a couple sleeves of each, having 60 of each on hand for future projects. Then at a later time get the bigger ECW20N/P20, or would these be better in this situation now? I’m guessing the ECX would be just fine as it is rated to be a bit more robust than these originals.

How do these new devices compare to the originals of the amplifier? I know when it comes to BJTs there are certain devices out there that are considered superior sonically and are coveted. You wouldn’t replace these with any new modern device as it would be a downgrade. I’m just trying to see if this is a similar situation.

Thank you,
Dan

The Cyrus Tuner voltage is too high for the facade lighting lamps, because the primary of the transformer is 220V, now we have 240V. I changed the lamps because they were burnt out. I replaced them with the same 12V 60mA lamps. So I need to lower the voltage which is currently 23V to 12V. I took the same diagram as the 317 already installed for other 5V, 13V and 24V use. I need your opinion, is this addition good? or do you have another solution other than a drop resistance.

Here's for your free non commercial use the last implementation of my phono preamp: HPS 6.1

What's new:

- A new servo in the head amp, allowing the use of an active load in the low noise stage; as a result, the PSRR is improved by an order of magnitude.
- A new power supply, much simpler, using the latest ultra low noise regulators from TI. TPSA7A4700 (positive) and TPSA7A33 (negative).

You will find attached the schematics and the Gerber files (including this time the much requested solder mask). The board size is 124.5 x 81.3mm so the construction is very compact. Any questions, feel free to ask. For the time being, only a few comments:

- It is dual mono, and requires separate raw power supplies (recommended +20V @250 mA -20V @50mA) for each channel (if you want to keep it dual mono all the way). Double the currents if you are using a single power supply for both channels.
- Supply voltages are +/-18V. This being said, you can replace the LME49610 high voltage buffer (now exctinct) with the lower voltage version LME49600
- For the low noise jfets, you can replace the now extinct BF862's with the still in production at OnSemi 2SK3557 or CPH3910 with a less than 5% penalty in noise. For the 2SK3557 choose the -6 rank (lower Idss).
- I have two more versions, one uses the OnSemi CPH5905 integrated cascode (same noise performance as the 2SK3557) and one using standard LM317/LM337 linear regulators (almost the same noise performance, board is slightly larger). The latter was a proof of concept to showcase the very good PSRR of the input stage, but I would still recommend the current version. I may eventually post these versions as well.

And a strong WARNING. This construction is not for the beginners. It is full SMD and while most of the parts are a convenient 1206 size, some are smaller 0402 and the TI ultra low noise regulators are in DFN package, difficult to solder. Skills in SMD soldering and the use of a hot air soldering tool is mandatory for success.

Finally, I have to add the usual disclaimer: I am not into group buys, selling boards, building BOMs for DigiKey or Mouser, etc... life is too short for such, so essentially you are on your own. Information herein is accurate to the best of my knowledge. This will be posted on my web site, as soon as I'll find time to do it (I am hopelessly in behind updating my web site).

Enjoy!

09/17/2019 Schematics corrected here: https://www.diyaudio.com/forums/analogue-source/333000-hps-6-1-a-4.html#post5917513

Has anyone seen anything similar in the DIY world? I would PAY someone for a clone or similar design! I don't know of a similar kit available. $8000 is soooooo far out of my league!

Hello,

I am looking for a connector assy for an RTW 1069A.
Please see attached photos of what I am looking for.
Should you have one that you don't use please PM me.

Thanks!
Vencel

HI folks

Been a silent visitor to this forum for a long time... I am a electronics geek and recently successfully brought back my Sub Woofer from the dead. Had a blown zener and dry solder at diode. But i am not happy with the result i want to get more into it and explore more .. ofcourse using my sound system as the guinea pig. So here i am starting on a very frustrating (comes with the territory) but rewarding journey.

Sale is withdrawn.

Joined April 17, 2014. Been quite happy to lurk all this time but finally found something comment-worthy so I guess it's also time to get my intro post out of the way.

I like old integrated amps, guitar amps and echo effects, pipe organs, and working on my cars. I hate snake-oil bullsh... wait, can I say that here?

I have two cats, two very elderly BMWs, and by the grace of god alone a wife who finds these aspects of my life charming. Ain't it grand, folks?

Hey everyone, I am overseeing an installation for a sound system in a new venue, and am interested in potentially going the DIY route.
I've come here to learn about the potential benefits of a custom-made cabs over perhaps a more generic pro system.

I’m using the PAM8610 breakout boards in an application where I rely on the “ramp-up/ramp-down” volume when the MUTE pin is used with the FADE pin tied low. I‘ve used over 20 of these boards with great success. I went to purchase more of these boards, and I’ve found that there are new versions of the PAM8610 IC with a subset of features, fewer pins in a smaller package, and yet they are still marked PAM8610. The new devices have 32 pins, whereas the original has 40. I suspect that the new devices are in fact PAM8006A—which is similar to the PAM 8610, but without the volume control and the FADE feature that I need in my application. In the photo below, the left-hand board is the original, the middle board I purchased from Amazon, and the right hand board I purchased from eBay. The left board has the 6mm square 40 pin package while the other two have the newer 5mm square, 32 pin packages.

The new boards do not have the FADE feature—they just snap from full volume to zero and back when the mute pin is toggled.

Current versions of the data sheet for the PAM8610 are marked “Not recommended for new design, use PAM8006A”. I’d like to purchase some of the old boards before they are totally gone.

The PAM8610 seems to have quite a following on this forum. Have others encountered this issue? Is there a source of supply for the original board? How can I ensure that the vendor is selling the old board when the parts are labeled with the same part number?

Selling this large lot of polystyrene caps, weighing a few kilograms. Revenue goes to the person I bought this from, it came with a lot of mustard caps that I was interested in. Seems to be quite unique in the sense that it has high voltage and high precision, and there's a large amount of values to chose from. I rather try to sell it on diyAudio, but if nobody is interested, I will place the lot on ebay at a starting price of 0.01$.

I have a B&K Precision 890C and tested a few large value caps, they were all within the range. I can do more measurements on request.

This is the full list of caps:

400V


Also includes an amount of 2% 350V caps


And some 500V

i want to pre-calculate the self capacitance of some transformers I need to design. To do that I need the thickness and dielectric constant (permitivity) of the enamel. When wire came from major western manufacturers, one could get that from the manufacturer. But I need to get data for wire of uncertain provinence (ie bought on eBay from Chinese sellers).
Is there an easy way I can measure thickness and dielectric constant of a sample of wire?
It is not sufficient to just measure the overall diameter with a micrometer, as the manufacturing tolerance on copper wire diameter is too large. I tried scrapping of the enamel so I could measure the copper diameter accurately but got inconsistent results - it is hard to tell whether I am scrapping off copper. I tried burning off the enamel with a gas flame, but that gave inconsistent results too.
Keit

I rescued a 5881 mono block from a relative and in the process of restoration. I assume it was build in the 1950s and remember listening to it in the 70s. This is a little over my head. My experience has been building known circuits with plenty of information online. I have replaced all of the mouse chewed wires, new sockets, checked and replaced passive components. With a little bit of research it looks to have a Van Scoyoc phase splitter? My first questions are the following:

Why two inputs? If I split a mono signal into both inputs it seems to cancel each other out. When I ground one input, works fine. A Mac C104 clone was used as a front end and from what I could tell from the remnants it didn’t have two outputs.

Don’t need to worry about oscillation?

Based on other articles I read should I have a balanced bias circuit on the 5881’s?

I recently acquired another output transformer so I want to make sure this is sound before moving forward with that.

Thanks,
Steve

Thought some might enjoy reading Tom's paper on phono preamplification.

61 years old...
Legend in alt music and recording engineer/producer with a DIY approach.
Way too young.......

Hi there,

Pretty simple beginner stuff here, but I don't really do much with transistor amps so I have never built a bipolar supply...

If I were to build something like this, delivering B+ and B+/2:



(...from the tubecad article here: https://www.tubecad.com/2012/05/blog0230.htm )

...in this illustration there are two resistors, I plan to use chokes but nonetheless - do the values of the chokes or resistors need to be identical?

If so, finding choke pairs is difficult. I would be motivated to build a stereo power supply if I'm going to purchase chokes. If the total demand on the power supply is about 300mA from both legs together, do both chokes need to be rated for that?

If the chokes do not need to be identical, the question of current remains. Can I have the top leg with a 200mA, as the output tubes take the larger voltage and the lion's share of the current, and a 100mA on the lower leg? The caps blocking DC make me think that this is the case... but as I looked up more examples of this kind of circuit, I kept finding that they had identical R values so... just gotta confirm...

The stylish French icon Françoise Hardy passed away at 80 after a long illness.
A collection of chronological pictures of this beautiful classy lady:
https://www.theguardian.com/fashion...oise-hardy-epitomised-french-chic-in-pictures


Picture: Discogs

Hugo

I am looking for pairs of the same listed impedance. Cones must be in perfect condition. Please provide pictures.

...Fiiinally time to start posting!

Greeting,

I recently had my +10db gain tube pre develop issues with it's muting relay. Which caused a channel imbalance so I'm in the process of swapping the relay. This caused me to insert my 0db gain passive temporarily. Which has caused quite a welcome ruckus on the analog end. As before I was experiencing pretty substantial subsonics that would end up effecting the tonearm producing compounding issues at higher volumes.

To make a long story short awhile back I had run all of the math on the adjustments on my hybrid phono pre. And found that with one setting, with this cartridge, that I could boost the phono output by around 6%. So the usual occured with the other sources, and especially with the CD player, the passive preamp lacks the last couple of volume clicks. Which has always been the case. But with the phono input it is just a giant step forward here. As the gain is sufficient and the noise and subsonics have for the most part vanished.

So I've determined that I'm going to add a set of passive outputs to my +10db tube preamp. And perhaps even a toggle that will mechanically select between active or passive.

This means that I'll have to source a appropriate shielded twisted input wire to add between the volume control and the switch and output jacks. And that has me pondering what type and guage to use. I'd like to perhaps introduce a tad more spice so I'm thinking silver or silver plate in a smaller guage. I've noticed the designers in this case have switched to copper from the past silver plate. At least in the active designs and they dropped the passive model from the lineup. So any thoughts on the best wire to use to introduce a little sparkle along with a tad more meat on the bones?

Many thanks,
DD

Hello, I am a third-year student in Audio Production at SAE Institute in Geneva, and for my thesis on DIY Bluetooth speakers, I am looking for people to interview. I have a few questions to ask, and it would help me a lot. Thank you very much.

Got a ev5000D it had a blown power supply cap replaced it and when I tried to power it up it went into protect. Pulled the power supply fets and the drive looks like this on the gate and on the 3525.

I have some old speaker cabinets that have rebated driver mounting holes - these are old subwoofer cabinets. I have several drivers that would work in these cabs but the driver frame OD is a few mm too large to sit in the recess. I would very like to use these drivers and cabs together, so I am looking for ideas to either:
(a) use something like a Dremel tool to grind/sand the rebate edge, going round and round while sanding, until wide enough. I am concerned that I might not be able to sand the very bottom of the rebate sidewall, or I might damage the veneer on the face by doing this.
or
(b) forget about the rebate - create a ring of wood to fill it in and mount the driver with its frame proud of the cabinet face. This would waste a lot of material, but would not require sanding.

Any other ideas? Advice?