Sorry if this might be a newbie question:

The background to my question is tube testing with uTracer 3+.
Often when I test allegedly NOS and used tubes, I get low plate current than what stated in the datasheet for specified conditiions. I read in few website that using fixed grid voltage is the wrong way to do emission testing. Here is my question:
Let's assume I test EL84 in the following conditions-
Va=Vs=250V
Vh=6.3V
Vg1=-7.3V
and I get the following results: Ia=30mA, Is=3.5mA

When I increase the grid voltage to -6V, I get Ia=48mA, Is=5.5mA

How one should interpret these results?

I have to say that I'm not in the position to trust the uTracer yet and currently I have no another tester to compare with.

Thanks!

Hi everyone!

I was given an Altec Lancing inMotion IM7 a while back and I shorted the subwoofer amplifier accidentally trying to mod it. One of the IRF7379 chips caught fire and burned up two small parts near it.

The IRF7379 I replaced:



The two smaller parts: (One of them says "KA2" and the other says "Z 2")



So far what I have done:

1) I replaced the IRF7379 that burned up. (Amp worked but had crackling noises)

2) I removed the two smaller parts and replaced them with others from another channel's amp, sound improved but horribly distorted at high volumes.

3) Removed the two replacements, put them back where they came from, and left the solder pads empty. No crackling but horribly distorted at high volumes.

^This is where its at now. What are the two little parts and where can I find them? Ive looked all over and don't have a clue. Also, what else could be wrong and causing the distortion?

Thanks in advance! If its totally screwed I guess I'll just have to buy a shiny new IMT810 haha.

Noob speaker box size help.

Hello everyone! I'm a newbie embarking on my first diy 2 way speaker build.I've read a lot of info on d.i.y. speaker building but can't understand a word of all the technical aspects. Basically I bought 2 Seas p17re h419 woofers and 2 seas 27tdf H1211-6 tweeters for the build. But for the life of me,I can't figure out the actual box size for them. The seas woofer specs say that vas for the woofer is 30.5l. Does that mean the actual box volume? Can someone help? Tia!

Any infos are hard to find over the web, any chance that could be change is count, so let's try 😉

I have Audio Institute VR-70E (widely known as Dynavector VR-70E) where originally a pair of 6F2 is on board. Not bad Chinese Valves, but there's always could be better. I've tried 6U8A RCA, but ECF82 Polam goes much better. Those Polish Tube Valves sounds better in overall, but there is a annoying problem with vocal sibilance (especially "S" syllable).
Is there any good sounding ECF82, 6U8A, or 6F2 known by anyone? Preferably with good dynamics, good bass control, smooth mids and without overbright hi-end?

PASS ALEPH 5, finally finished the realization of this finale.
Thanks to Maurizio for the inspiration and Eugenio for the technical support.

For Sale: Tubelab SE PCB Version 1 (original board)


I have a Tubelab SE PCB original version that I never used and I’m clearing house. It’s in (as new) condition. Its been stored in its original shipping and stored on the shelf in a plastic tote since I bought it. I built the Simple SE first and then went down different roads and never got back to it.


Also included is a DVD published by Elector all about Valve Amplifiers.


$45.00 shipped in the USA. Paypal.


Thanks.

For Sale: diytube GetSetGo PCB.

This is a PCB to build a directly heated, Single Ended Triode Design tube amp.
It comes with printed instructions to build the amp which includes parts list and schematic.

Probably not for the person attempting there first amp kit (unless you’re an electronics expert just getting into amp kits).

$45.00 and I’ll ship it at my cost if in the USA. Paypal.

DIY Audio Electronics from Zynsonix.com: DIYTube Get*Set*Go Single Ended Amplifier
Get*Set*Go--6B4G or 2A3? | Audiokarma Home Audio Stereo Discussion Forums

Thanks.

This is a fairly recent part, which looks to promise a fairly simple 20W Mono amp. Further, it looks to have a DIY friendly SO-16 package, with 50 mill pin spacing. But the devil is in the details. Here's the spec.

http://www.mouser.com/ds/2/115/PAM8320-273748.pdf

My question is about whether it is even possible to build an amplifier powered by a single 12V source.

The backstory is, I was considering these very inexpensive and ready made STEREO boards, based on an older PAM8610. You may find these interesting too, especially at this insane price...

PAM8610 Digital Amplifier Board 2x15W Two Channel Stereo Class D Sale - Banggood.com

I inquired to Diodes Incorporate whether i could couple the inputs together on that board, and also couple the outputs together, maybe through 0.1 ohm resistors (to add balance) and a 4 ohm speaker. The engineer at DI responded saying it would work, but it would be more efficient to use the MONO 8320. But looking at the data sheet, I'd almost get the impression it requires three power supplies (one bi-polar supply and a separate supply for the preamp / logic section.

Again, this is a pretty new offering so there is not a lot of example applications out there. I've requested some samples, but if I can't use it with a single 12V supply, its not going to be a very useful part for my needs.

thanks for any assist/advice.

One of my old developments: usb interface ui-01

Galvanic isolation Si8640 and Si8662. Clocking from the DAC / ADC board, power supply - primary AMS1117-5.0, then DC-DC at 3.3 V and DC-DC at 1 V to power the core. All connection schemes are based on datasheets. 1 input line, 1 output line. Self Power, i.e. not from USB.

PCM Data I/O 16-32 bit, 44.1-384 kHz, 2 I/O lines (stereo in + stereo out)
DSD data output: Win - DSD DoP 64-128, Linux: DSD native 64-256.
8 GPIO lines with the ability to install Si864x isolators.

MCLK - 512fs

My end goal is:

1. Single ended with choke CCS
2. 40W into 16 ohm @ 1% THD.
3. 100 ohm output impedance or more
4. At most 100W dissipation
5. As little feedback in loops as I can get away with

A variant on the Big MOFO or similar with a frontend would be perfect except it has a low output impedance. I could wrap a current feedback loop around it to raise the output impedance but if I've understood correctly I'd have to use a lot of feedback to get my desired output impedance. And in addition to that I don't need the distortion reduction of the feedback, it already performs good enough. But could I do the F7 trick but in reverse? That is I use a modest amount of positive voltage feedback to raise the output impedance by a lot in addition to a normal negative current feedback loop to prevent instability.

I read somewhere that Nelson wrote that the F7 positive current feedback was 2 dB and reduced the output impedance by 30x. If the same trick works in reverse with positive voltage feedback then I could get by with less overall feedback to get my desired output impedance which would be great.

And so I threw together this circuit. If I've understood correctly the drain pins are inverted relative to the gate but the source is not. Hence I believe that the circuit will apply negative current feedback and positive voltage feedback. Unless I messed up somewhere which is pretty likely 😀

And as I write in the example I'm not sure if Q2 should be connected to Gnd or the current sense. My gut says if it has the same ground as Q1 it won't apply any positive current feedback but I'm no expert so I might be wrong =)

Are there ways to DIY clone LS3-5a at reasonable cost? The cost or cloning difficulties with expensive drivers or crossover? Thanks

For Sale: John Coltrane “Interplay” 5 disk box set issued by Prestige


I bought this box set while in college and listened to it straight through one time. It has been stowed safely in a plastic tote for a few years. My job has me travel throughout the US South and East sometimes to foreign lands. I need to move again (for my job) and I am cleaning house. My tastes have changed and I just don’t listen to it.


The set is in “as new” condition and includes the book articulating the time and era these recording occurred. I don’t think I ever even thumbed through it.
$50.00 shipped in the US. Paypal works best. Thanks.


Review here: Interplay - John Coltrane | Songs, Reviews, Credits | AllMusic

For sale a complete set of pcb + 4x5LN01SP + arduino nano
25 euros + shipping



IMG 20200811 114541 2 — Postimages

I am strugling finding the propper mica insulators for these output devices.
I looked at Digikey and, can't find those!...
What are you guys using?. These are for a Kenwood KA-701.

I have 4 used audyn 10 uf caps. One lead on each is cut.
$50.00 usd plus shipping for all 4.
Thanks,
Evan

Modelling this in Winisd.

How is a 4th order with an "infinite" sealed chamber any different to a ported box?

Cone excursion models the same, but the frequency response suggests there will be an 8dB gain at 18Hz.

Is this actually going to be the case?

The "port gain" graphs for the two enclosures are basically identical?

Hi,

Maybe someone knows. I’m mounting a horn on top of a bass reflex cabinet. I need the wire from the horn to run in the box via a hole. Is there some kind of small metal grommet I can use to accomplish? I’ve seen some backs of systems and there’s some kind of small grommet but all I can find is shelf pin grommets or fabric ones (the rest are large for like desks and power cables).

I’m using 1” solid wood so I need a finished look.

Thanks in advance for your help.

A Samsung AV Amplifier delivers its output into 3ohms on all channels. The system sensitivity of the speakers is quoted as 86dB.

The driver in the sub was unserviceable. It has been replaced by an 8ohm driver with a SPL of 92dB.

(1) Is the balance between sub and satellites pretty much where it started?
(2) Will the change in load have a detrimental affect on the amp?

Despite thinking i would buy a volt + amp i think i would go for this amp (price power ratio)

AUDIOPHONICS TDA-S50 Amplifier TDA7498E Class D 2x 50W / 8 Ohm

AUDIOPHONICS TDA-S50 Amplifier TDA7498E Class D 2x 50W / 8 Ohm - Audiophonics

I have a 24v 6a power supply but i can get 2 power supplys so the total price would be no more than around 70 euros

ALIENTEK AC/DC Switching Power Adapter 100-240V to 28V 4.3A

FX-AUDIO AC/DC Switching Power Adapter 100-240V AC to 32V 5A DC

What is recommended to buy? Any other suggestions from a european store?

Say guys, i found 2 dreadded black flag caps in my integrated amp!😡
I found these: 399-9787-ND # at Digikey. Would these be suitable please?.
The OEM's are 100PF. Blocked

Thanks guys!!!

Hi there,

i've got myself an old Ampeg B15 N which had his original 110v power transformer switched to an Ampeg european 220v one.

It all works, i mean, i can plug a bass/guitar and ear it coming out of the speaker.
but i have a relatively quiet but unbearable oscillating noise at all volume. (The noise's volume changes with the amp volume.)
i've changed the pre tubes and the can cap, still the same problem.
Here's attached a sample of it recorded through my phone pointed at the speaker.

does anybody know this sound ? and of course, does anybody know from where it could come out ? what do i need to check ?

i'm not a high level electronic guy, and don't have a variac or an oscilloscope.
only a multimeter, an iron and some common sense.

thanks in advance,
Fred.

Hello everyone! I'm a noob and want to build a 2 way speaker using Seas p17re h419 and Seas 27tdf h1211. Despite reading so much on this topic, I can't understand what's T/S parameters etc to determine box size for this 2 way speaker. Can someone help? TIA!

I bought a Wilson Benesch Circle about 15 years ago. My local Linn dealer adapted a Lingo 1 (year of production 1993), this was possible because the synchronous motor is similar to the motor of the LP12. Everything seemed to work properly.
But last week I checked the output voltage of the Lingo. It starts with 95 Vrms (stall mode) and changes after a few seconds to 60 Vrms (normal mode). So far so good, but afterwards it toggles continuously between the two modes. If I removed the belt i.e. no-load operation of the motor or changed the speed to 45rpm, but the behaviour remains unchanged. In stall mode the motor produces audible and sensible vibrations, therefore in the moment it would be better to feed the motor directly with 230V line voltage. I found a complete circuit diagram of the Lingo 1 in this Forum, but did not understand the control circuit. Maybe someone can explain to me which parameter forces Lingo to switch into the stall mode? How can I find out if its a problem with the Lingo or the motor? Would a recapping solve the problem?

Regards
Martin

Anyone have a schematic or kit for a remote control for my pre amp?

This amp is using MTP50N05E as the power supply fets .

Would the 3205’s be a good replacement ?

I have a technics sl-ps900 that has stopped reading discs not sure weather it is a capacitor problem or laser was going to change the whole laser tray mechanism off another model to fix it but not sure what other models use the same mechanism ?

I recently built an 12AX7/KT88 prototype (I do not have "current" schematics for it, sorry), and I think it sounds good, but it is not very loud. I seem to be about to get around 100dB out of it on-axis from about only a foot away from some crappy desktop speakers. I'm also going for more hi-fi than a guitar amp, so I don't expect maximum gain(and I realize a negative feedback loop is missing, not relevant to the question however), but I'm still trying to figure out a few problems.

I looked up Uncle Doug's tutorial on how to measure power output from it using a 1kHz signal on an 8 ohm dummy load, and from my memory I was only getting a few watts (literally like 3W) out of it.

I'm powering it out of an old iPhone which I'm estimating only puts out about about 250mVrms.

Also my OT is a Hammond 1628SEA from Digikey (https://www.hammfg.com/electronics/transformers/audio/1627-1642.pdf). It's a 5k input impedance to multiple outs(I'm using 8), supposed to be rated for up to 30W.

I understand different frequencies will have different responses, etc, but I wanted to try an exercise in LTspice to see if I could work backward, even if strictly theoretical and possibly unrealistic, and just pump in some raw numbers to see what I would get out.

Here's my slop-matic:



There are many obviously unrealistic things about this schematic, but for the case of modeling, the idea was to swing the grid between -5V and -35V against a 530V B+, using a model(hopefully correct) of the OT matching the Hammond, into a dummy 8ohm load and see what I would get out. In this case, I was getting about 3.2Vrms across R10, which should translate to about 1.28W.

With the OT windings being 25:1 for 8ohm, my guess were that if I wanted to get this to 10x as much (12.8W), the secondary would have to swing 32Vrms, which means I'm at 800Vrms on the primary, which is more than B+ supplied even if I'm going after the opposite swing from the transformer.

I guess what I am trying to do is start a design again, working backward, and figuring out what I need to feed the OT, then what I need to feed the power stage, etc, etc.

I'm sure the things I'm doing wrong are almost innumerable, but if someone can point out a few big hitters, I can get my mind back on the right track.

Thank you!

I have been thinking of doing a new F6 pcb to implement some of Nelson's updated circuit ideas as well as some of my own.

As well as a B1 type circuit that was presented by Nelson at one of the BA festivals.

I would intend to make it available for store use.

Is this something the store might be interested in.

Another AG9016 "addict"

Hi,

first of all my copliments on this forum, especially the links on tube related articles, often on entry-level, are very very helpfull.

As a brief introduction, I just finished (re)building my first EL84 SE amplifier (Kontakt KT7). Although I bought the amp in "working" order it needed some new capacitors and a by-pass of the input section in order to get a reasonable sound.

After a while I decided to fully strip the amp, and rebuild it from scratch with new (and preferably better) parts, and although I had minor knowledge on tube electronics, I managed to get it up and running again.

I am actually working on a site were the rebuilding process will be described in full with detailed pics, and as soon as it is finished I will drop a link as I feel that this could be interesting for other applicant Kontakt/Bocama/Lafayette rebuilders.

Now only recently I bought a philips AG9016 amp which is the next project I want to dig in to. I have read the topics on this forum on this amp, i.e. 40 yrs old philips AG9016 flea-power ?,
and there seems to be somesort of "improved" schematic were most of the C's and R's are removed?

There was actually an article in a magazine called A&T (!?!) how to "pimp" this specific amp, but somehow I cannot find it anywhere on the net.

To make a long story short, all (schematic) information, additional tweaks etc., are more then welcome !

Thanks in advance

Cees66

I'm trying to get amplification to drive a single passive 12" PA system, rated at 200 RMS, and an additional passive 12" subwoofer, rated at ~300 RMS. The amps will run off a buck converter connected to a 12v deep cycle battery. I'm looking for cheap, powerful, and energy efficient.

Right now I'm looking at buying two TPA3255-based amps:
AIYIMA TPA3255 Subwoofer Power Speaker Amplifier 300W Mono Hifi Home Audio Amplifier NE5532 OP AMP Bass Treble Adjust|Amplifier| - AliExpress ($45 each)
and run one in PBTL mode and one in SUB mode. It seems that the input power is limited to 35v, so I think this will give me ~120w RMS at 8ohm, for ~90$.

I'm wondering if there might be a cheaper, more powerful, or more energetically efficient solution. One idea I've been playing with is using a single TPA3255 with two output channels (2x300w), feeding in a mono main PA signal on the left input and the pre-filtered mono subwoofer signal as the right input. This would let me get away with using a single amp, for ~$50, also I'm imagining ~120-150 RMS at 8ohm, and possibly half the energy use. However, I'm not sure if this is feasible, in particular if feeding in main PA/subwoofer signals as left/right differential inputs is a good idea.

Any advice or thoughts would be appreciated.

I'm upgrading to a (far more expensive) audio precision system.

Selling a lightly used Quant Asylum QA401 Audio Analyzer & QA450 4/8 ohm load.

Comes with accessories and cables to measure your DAC, amplifiers, speakers, etc. SNR, THD+N, crosstalk.. Lots of insights.

QA401 Audio Analyzer



– QuantAsylum
QA450 Programmable 8/4 Ohm Load [Retired]



– QuantAsylum

$500 + Shipping for both.

I would consider selling the QA450 separately.

I just finished building a Nutube B1 and a ICE Power 500ASP + 500A module. I noticed an increasing high pitched noise coming from the 500ASP though, the 500A seems fine and Im not sure what can it be. Im using star ground at power supply and connections seems as 500ASP user manual



Any tips on where to start debugging?

Quick question; I'm thinking of doing a 15" build with the above horn, or something like it. I want to WAF it as hard as is practical, because whilst the new other half is quite prepared to let me build whatever I want, I don't want to look at an ugly speaker! How thick can you get away with painting the horn before it is detrimental to performance?

Cheers,

Russ

Brian Bell Chipamp.com Aleph Boards + Power Supply Board. They have been in my parts drawer for many years...

How about $40 shipped CONUS?

Please ban the term "Chi Fi" from the forum. It is an example of cultural racism. I know that not all people, including forum management may be aware of modern forms of racism, so I will spell it out. Chi Fi is cultural racism because it's very usage implies that "Hi Fi" is the normal state, and "Chi Fi" is the non-normal state, and of course normal is therefore not Chinese. Research racism yourself if you do not accept this.

As promised a while back, I simulated the NAD 3020's line stage. Total output noise comes out to ~3.7 µV A-wtd. Including the 23.7 dB power amp gain of this 25 wpc amplifier that brings this up to ~56 µV, this means a total (best-case) SNR of about 108 dB(A), slightly short of the claimed 110 but still very respectable for a little old amplifier.

With the (20k) volume pot turned down for a 2.83 V output, I'm getting ~111 µV(A), so about 88 dB re: 1 W / 8 ohms. Not too shabby at all.
Turned down further for 50 mW / 4 ohms, it's 68 µV(A), so about a 76 dB score on that.
There used to be amplifiers with even lower noise despite substantially higher output power, but those used a two-stage volume control (4-gang volume pots).

LTspice schematic attached.

Try and guess where you'd go to attack this Castle, and then post one of your own favourite or strangest places.

Okay, so after this thread and warning shot..

https://www.diyaudio.com/forums/sol...-psx-blows-fuse-mains-plug-2.html#post6301599

time to replace the 4 x 15,000 uF 63 volts in the PSX.

Looks a simple job, just 4 caps to desolder and resolder.

So which replacement caps are suitable based on uF, voltage and sizing.

I just quickly Googled, 15,000 uF, 63 volts - I think that's what they are...

and found these on Mouser...

LKG1J153MKNF Nichicon | Mouser United Kingdom

Are these any good ?

and recommendations ?

Hi All,

I have a CTS2000 that I am working on. There are couple of SMD ferrite beads fried but I can't seem to find a reference to what their value should be. On the Schematic drawing 134274-1 they are listed as FB915, FB914 and FB913. Does anyone have any idea what they might be?

Thanks

Hello,
I need the schematic diagram of the 35 watts amp PA-935 from Inter-M or Inkel
It's the version with all screw terminals at the backpanel(Not PA-935N)
I downloaded a diagram from the WWW, but thats hard to read.
The diagram is in the original manual, but I don't have one.
Who helps?

I just got the edict from my wife that Alexa is creeping her out, and that I need to find a different solution. I also got permission to spend money!😀


I'm looking to setup a locally hosted smart home assistant, and wanted some recommendations on small (<=3"), inexpensive (<$15) speakers of reasonable volume, and that are clear enough for the synthesized voice. It would also be nice if the overall depth was somewhat shallow.


I've used the FE85 in the past (currently listening to them now actually), but they need a (relatively) big, sealed, enclosure to sound good. I plan to 3d print the enclosure, but I don't think I can get away with sealed since I'm gonna put a rpi and microphone array inside. Some of the neodynium speakers from Dayton Audio seem like a good match, but I'm not sure if they are any good.



For the amp I plan to use this TDA2822M based amp from parts express: TDA2822M Low Voltage Stereo 2 x 1W Audio Amplifier Board (although I may not actually need the analog volume control if I can do that digitally). I know its <$5, and I will not be using this for playing music; are there any fatal flaws that would prevent me from using this amp?


Thanks all!

Split from http://www.diyaudio.com/forums/multi-way/68301-my-morel-mtm-project-6.html#post4796981

I have a mw144 with 30s in a transmission line. The cab is near enough the ipl M3
link: IPL M3TL mk3 Transmission Line

I think it's 8 years since I first posted, looking for help. I think I had probably been at it 8 years then. On and off.

They are OK, with a 2nd order about 2.8khz. It's nothing special though and I have taken many db away from the 30s to improve things. Leaving the tops about as loud as the bass, but a hump between 500hz and 1khz making them sing more than dance. I like dance.

Time change and so have my hobbies. It's electric bikes now. I would like to try some different crossovers though. Just not design them. Are there any designs about that are polished enough to copy with reasonable success?

I am combining a 700AS2 and a 200AS2 in the same chassis. I want to use the the 700AS2`s 12v trigger function to bring it out of standby. The problem is that the 200AS2 is normally on, and can only be put in standby with a 5v signal.

Would it be possible to connect the standby led output from the 700AS2 to the standby input on the 200AS2? It requires 2.8V on a 20kohm load to trigger.

I have attached the datasheets for both.

I have an earphone that I often use while working. The single driver allows me to listen to music yet still hear and converse with coworkers and customers. Somehow the outer jacket of the cable got abraded, exposing the inner wires and the ground shield.
I lucked out and found that dipping the worn section into a can of "As Seen on TV" Flex Seal and hanging it to dry is the most perfect repair that a person could hope for.

Hi friends,

I want to go with a mw16p+tw29r sealed 2 way, and I want to add some bass.

1st option The kairos 3way module featuring sb29nrx woofer per channel

2nd option powered subwoofer, mono peerless xls with passive radiator going really low and tight.

Realised I posted this query in the wrong place.

Title should be repair, upgrade or replace amp boards.


The darlingtons (mj11015/6)on my Virtuoso power amp have failed and I'm considering replacing the amp boards for something more modern and better than the Virtuoso. It's an old design by Graham Nalty in ETI with loads of esoteric components, holco h8 and h2 resistors, Mat02 (ssm2201) transistor pairs, wonder caps. I've added schottky diodes, silver wire and kimber cable etc.

The power rails are +-56v dc with a separate regulated supply for the low power gain stages.

To put it into context, it's current build it is better than a rotel rb-991(more air and detail) and recently caused a friend to upgrade his Naim 140s. I haven't had the chance to compare it with anything else recently. My friend was supposed to bring his naim 250? over but covid got in the way....plus I blew my amp up

Alternatively I could consider alternative better darlingtons or mosfets (the amp was also designed to allow mosfets RFM10N15/P15 to be used with the removal of some parts and adding gate resistors.)
I was looking at faster darlingtons or the exicon mosfets but to tell the truth I have little idea on what other changes to ensure that they will work.

It also needs to be able to drive my Martin Logan Sequel IIs and handle all genres of music from classical, folk, blues to rock as I listen to all good music irrespective of "designation"!

Pre-amp is Versatile LDR designed by Rudi_Ratio who kindly posted his design and organised a group buy on this forum. Sounds Great!! Thanks also to George who did the groundwork for LDR preamps.



Any advice or suggestions appreciated.

Hi All,

I have a CTS2000 that I am working on. There are couple of SMD fuses fried but I can't seem to find a reference to what their value should be. On the Schematic drawing 134274-1 they are listed as FB915, FB914 and FB913. Does anyone have any idea what they might be?

Thanks

I am using PSUD2 to design a PSU using 5AR4 rectifier.

I think I used too much capacitance, but it can't be helped. During the first second it throws a warning about the IFRM of the rectifier is exceeded.

I'd imagine the rectifier tube isn't warmed up yet at that point and shouldn't be conducting much. Do I need to pay attention to the warning?

Or do I need an inrush current limiter?

Hi

I would like to build a pair of low wattage monoblocks using Hashimoto, Audio Note, Tango, etc. transformers like the ones in the attached photos.

Are there any projects available?

Cheers,

During the last days, I was reading a lot of posts about paraline, combining compression drivers, directional arrays, Unity/Synergy horns and so on.

I wonder if there is a way to integrate for example JBL2445 or similar driver that is lacking in the HF with some sort of device to have point source behavior at a relatively short distance - say 1.5 m and further. If possible, it would be nice not to use digital delay between the two units, but can be used if necessary. I would like to crossover the JBL2445 at around 600 Hz

The best I have tested so far was to use two identical horns for the JBL2445 and HF compression driver with an adapter to match the time of flight to the listening position and to integrate well at least in the horizontal plane. This is as good as I can do. Would it be worth trying to pursue alternative ways?

The tools available include a 3D printer and DSP for delays, crossover and EQ.

I see some potential ways to try out.

1) use two paralines to combine the 2" and HF drivers into a conical horn. One shorter, one longer, maybe trying to steer the wavefronts a bit towards each other. The path lengths could be matched by using phase plugs going into the throat of the 2445 and HF driver to keep the conical expansion as close to the throat as possible, the HF driver would include an adapter for the correct distance.

2) use one paraline with both drivers - matching the pathlengths mechanically should be possible as well.

3) Use Danley throat combiner-like device to use both in one horn. Or any other similar device to make the drivers combine into one horn. The HF driver can be again made to have a 2" exit and same distance from membrane to throat as the 2445

4) "Inverted" Unity - to have the 2" driver in the center and multiple HF feeding into the horn. Most probably a very bad idea.

5) Place a small HF with horn inside the MF horn hidden in a phase plug like device and use delay to match the path lenghts.

6) Similar to 3, but Unity style - the 2445 would be fed to the horn through the side of the HF throat adapter at the correct place.

7) Anything else? Including that to have two identical horns is as good as it can get? And that a conventional unity is better in this regard...I would really like to use the 2445s.

All of above should be possible to at least prototype with a 3D printer, so any guidelines would be appreciated - e.g. rule out the really bad ideas. The 2445 can be equalized up to some 8 kHz without sounding too bad. The desired coverage pattern would be 90Hx60V or smaller, as low as possible. In this case, space occupied by the horn(s) is not a concern.

Working on some “450w” kits. I figured the rating was for 4 ohms, with the OP and drivers rated at 230vce, I stuck it into a +/-90vdc psu. Tested and got about 350w/8e and 550w/4e at clipping. The kit survived, one of them is in service running the mid woofers in my HT system for a couple of years now. As I look around to make a few mods in another one of these, I notice the input stage comprises mainly of 2sa970 and 2sc2240’s. If memory serves these are 120vce devices.... and they are subject to the full 90vdc on their emitters. I am wondering if I should change them out for something in the higher voltage range or leave them in there.

Any suggestions?

I just finished building an amplifier with a preamp inside. Im splitting the AC input into the amplifier (directly) and the preamp + input selector, through an AC/DC converter.ñ, the input selector has a buck converter to go down to 5v (from 24v) Everything with star ground at main.

What I find weird is that if I touch with the black line the + of the preamp (24v) and the + of the input selector (5v), it shows continuity. The same if I touch every other point (except for the AC wired). Is this expected?

Hi all

I've just acquired a Croft Series 7 power amp to drive my RX5 speakers. Preamp is also Croft.

It sounds pretty good but I sort of thnk the RX5 isn't the bestmatch - fun but occasionally closed in a bit

I'd be grateful for suggestions of speaker kits which may go well - IPL acoustics trasnmission lines or perhaps Wilsmlow Audio or anythig else recomended.

Time short for doing my own cabinets from scratch!

Thanks all
Listen to almost anything but lots of choral and organ music.

I bought an ICE Power 500ASP + 500A module and while reading the design manual, I noticed they use a buffer capcitor of 10000uF/150V for (star) ground and Im wondering, what’s the reason for this?

https://www.parts-express.com/pedocs/manuals/icepower-asp-series-manual.pdf page 44

They also mention this at page 12
“Adding an optional capacitor on the main DC-bus will significantly increase t150 as evidenced by the numbers given. This can be exploited in subwoofer applications, where it results in improved ability to handle transients”
But cant figure out what does it means

Hello,
It's about an audio codec ADC/DAC CS4272 https://statics.cirrus.com/pubs/proDatasheet/CS4272_F1.pdf I'm trying to put it to work with this USB to I2S module XMOS Multichannel high-quality USB to/from I2S/DSD SPDIF PCB - DIYINHK Schematics are attached, as well as the DIYINHK module requirements. Connections seem quite straightforward. I'm assuming that BCK is the same as SCLK, correct?

The DIYINHK module gets recognized by the PC and the drivers are loaded. But I don't get any sign from CS4272. Even Vref and Vcom stay at 0V. Vcc and Vdd are OK. To my understanding this means power down mode, doesn't it? I tried two chips I had available and both do the same thing. There is some info on CS4272 datasheet page #35 about ADO/CS (pin #13) but my lack of knowledge doesn't help me with this... In my case (copied design) ADO/CS is attached to ground. Do you think this could be the reason?

I realize that remote debugging is too much to ask so, I would appreciate if you could at least verify Cs4272 and DIYINHK module campatibility.

Hi all! I'm new to this site, but during lockdown I have re-kindled my love of HiFi.

Back in 1975 (I was 17) I purchased a pair of KEF Kit 3's and filled my bedroom with 2 large home made cabinets. Marriage and kids came along and we could no longer accommodate the 'beasts'. I kept the drive units and crossovers and the boxes went!!!

45 years later the drive units were dusted off and tested (one B110) dead, the rest fine and the crossovers re-capped.

By chance, a pair of R50 cabinets appeared on the web and transported back to our home France. 2 Manocor AD 135's (to replace the B11's) purchased and everything soldered and screwed together. In total these speakers have cost me less than £150.00 and they blow my socks off! A lovely 'open' soundstage and soft rich bass. I'm hooked!

Hi friends. This my very first post.

First off, I decided to name myself after what I think is the most fascinating amplifier topology I have ever seen - the circlotron. It is a model of simplicity and symmetry. I particularly like it because after drawing the basic circuit about 50 different ways to try and make it look the most logical, I noticed that if you place 2 loudspeaker loads on it, 1 between the sources and the other between the drains, it can be drawn as a perfect tetrahedron! As far as I was concerned that was the icing on the cake for a most aesthetically pleasing ampifier.

Now that I have firmly established my reputation as a nutcase, uh, sorry, *enthusiast*, Let me talk amplifiers. I discovered this circuit only a few months ago, and as it turns out I have quite a few large collection of hexfet switching type mosfets laying around at home. The last mosfet type amp I built was the Electronics Today one, back in about March '81 I think. It used complementary fets and I never felt comfortable with P-channel devices. They always seemed the poor cousin (or brother/sister?) to the N-channel. Then I found the circlotron cct that would let me use both N-channel devices. Coolarama! I wound up a driver transformer, picked a matched pair and away it went.

I started a thread on Google Groups that I will part copy and paste to here, telling of my adventures with this cct if anyone is interested. One unusual thing I did was to use a ferrite core tranny normally used in a switchmode supply for the driver tranny. With sufficient turns on the core it works really well, contrary to the advice I was given by others.

Anyway, I think the topology is the greatest thing since sliced bread. I hope there are others out there that are perceptive enough ;-) to also see what is so great about this cct.

Regards. GP.

Hi there!

I'm having some trouble and thought this might be the best place the check. I've left VMs and emails for anybody that might be in the know but haven't heard anything back.

I have the Focal Chorus 836V

https://www.focal.com/sites/www.foc...rus-800-v-enceintes-colonnes-chorus-836-v.jpg

with:

http://www.easylounge.com/Content/photos/f/o/foctweeter-tnc,33223-1200px.jpg

I got these speakers recently from a family member that drove them with a Emotiva amplifier without issue. As soon as I plugged them into my Onkyo 805 it blew the crossovers and the the tweeter/midrange on the one side. I assumed it was only the crossovers so I had them redone but of course the drivers are still not working despite having all the blown up parts in the crossovers replaced. I have a centre channel with the same mid and tweeter that I'm not using so I'm trying to use the components from that. The mid is easy enough but how do you remove this tweeter that seems to be glued on? Frustrating!

Hello, the last time i had a few difficultys with this type of amps.

Repaired the outputs... On some amps, it was also neccesary to change the irs 21844s.. Checked everything, complete new batch of mosfets. All parts from mouser. Tested the gate-source with a cap, everything looks fine. Final check of the amps also ok.. Customer happy, everything works, even under full load for a longer time... After a few days, or a week, the amp goes in protect, with small load, or only on, with no music playing..


Found two output mosfest short, one highside, one low side from the same bank. Couldnt find anything wrong...


Is there something, what i dont see, maybe somebody can give me a hint, where or what to look...

Hello

Anyone would have the schematic of the hitachi ha-410 integrated power amp ?

Thank you

Gaetan

Evening all, I was searching for Kaneda and came across this site. Mods, if illegal, plse remove.🙂
https://sites.google.com/site/franc...system/app/templates/print/&showPrintDialog=1

Hi,

After the great succes of my last project and the commercial interest for selling them. I thought I should design an ultimate reference system to dream off using the same philosophy to keep myself busy and just for fun. It will be a 4-way system plus subwoofer towers. The subwoofer towers will consist of eight woofers per tower mounted on the sides, in opposite directions to eliminate vibrations. The question is, what would be the ultimate woofer? The Scan-Speak Revelator 32W T00 or T01, or the one of the 15" Acoustic Elegance woofers?

Would like to hear your thoughts

Hi Guys,

I am building a mini line array with 12 midbass drivers and a 6 inch ribbon centered be tweeeen the midbasses.

My question is what are my best options for wiring, they are 4 ohm I was thinking of keeping them 4ohm.

How would I wire 12 of them and keep the original impedance of 4 ohms?

new to the forum, but thought this a great place to sound out a potential project. After looking for a fun and nice sounding horn loaded speaker for a 2 channel set up, I've started thinking of building my own speakers. I've built up several guitars and guitar amps, but never any HIFI projects. I really like the idea of making something mine. I've been looking at all these great looking cinema speakers lately from JBL and Klipsch. Would love to have those in my listening room, but they just seem overkill. So I have a line on the some Altec Flamenco's, with some beat up cabs. Started thinking about building up new cab's for the woofer and mounting the horn on top like I see on the cinema speakers I mentioned.

I've done some searching for plans, that's how I ended up here. But, can't say I found anything specific to what I am looking to do. Hoping some or a few here can point me in the right direction as to the necessary considerations for such a project. Who knows, maybe I'm getting way ahead of myself, nothing is ever as easy as it seems. But I always looking for my next project.

Check this YouTube video out. The WW2 "vintage" dynamometer uses at least 2 tubes.

Anybody with solid info. please comment in the video and post here.

TIA.

Hi,

Looked at couple of youtube videos of "diy projector", whose links are given below, and just thinking about it.
Any idea regarding it??
Can we source the components locally (Chennai or India)?


YouTube

YouTube

After a month of tweaking, I am now very happy with my results. Thank you guys from these forum who unselfishly shared their knowledge and experience.

aou 8.4 in panel
unsplit fresnel lens
250w hqi-ts osram
condenser
soup laddle reflector
gilkson projection lens

I have seen this on the web. Cheap, so I ordered it.
Desoldering Suction Pump
– Finggywow

Hi Gurus,

A friend of mine as a venerable ONKYO DX-G10 Grand Integra CD player (European name for the Onkyo 6990 Grand Integra).
The belt is dead and therefore there is a problem when trying to open or close the tray.

By searching on different web information sources (CD-Player-DAC-Transport List) it seems that this CD player is equipped with a Sony BU-1E / KSS-190A mechanism.

I would like to know if the Sony BU-1E and KSS-190A are exactly the same mechanisms, in order to know the replacement belt that I should order ?

I have found replacement belts for the KSS-190A on the internet but nothing related to the Sony BU-1E ...

Thanks

Folks:

It's taken me a while to figure out the source of the problem, but the WiFi powerline extender devices (TP-LINK AV500) that I am using to link my server to the house router create audible "popping" and "scratching" sounds when I listen to my turntable. The noises created by the powerline extender are inaudible when I listen to my server or FM radio. There are two separate 15A circuits powering my front-end equipment and the powerline extender and turntable are on separate circuits.

I cannot snake an ethernet cable from my router (third floor) to the server (basement), and the powerline extender otherwise works flawlessly. Does anyone have any idea how to eliminate or filter out the noise?

Regards,
Scott

Hi all,

Here's my latest creation, the F5/Mezmerize integrated amp. I needed something to replace my old but trusty Denon 3802 HTR that would do justice to the Pearl 2 I built a year ago.

6L6 provided a ton of guidance as I worked my way through this four month plus project. I'm thrilled with the result -- it's like listening to my music collection for the first time all over again.

Thanks to DIY Audio for making these boards and case available, and to Nelson for the fantastic designs.

Hi all
Amp came with complaint no audio. Visual checking found the jumper connecting two high side fets had burn the board.

I changed the two irs21844s ic and resoldered the connection and removed the bad fets. Now amp going into protect. I removed the main rectifiers and it is still going into protect. All output fets out of board.

My Motu 896 Mk III died during the power outage from the tropical storm. When we got power back, it would no longer power up.

I've replaced the Fairchild Power Switch, recapped the PSU, as well as replaced the optically isolated error amplifier. The diodes all measure good. The line fuse is good. All resistors measure within a couple percent of marked values. Nothing burnt.

I've even tried disconnecting the load and starting the PSU, but only the reservoir cap charges up to 160V.

Basically, I've replaced everything but the transformer. It's starting to seem like that is the failure point, but without schematic, I'm working in the dark and don't know what windings correspond to what pins.

I've asked MOTU if they'd sell me a new PSU module, but they said no.

I may have to give up on repairing this.

The voltage requirements are a little more than basic.. 3.3, 3.8, 5, -8, +8 volt rails. Almost could use a computer power supply, but don't know if running the 3.8 at 3.3 would pose a problem.

hi all

I have this amplifier p600.2.

It is having 4v from terminal ground to the rca ground. Due to that I think the relay is not coming on and amp even though comes on led remains in protection. Once relay is removed protection goes and has good output on the relay points. Pictures attached.

Disassembling a retired CD player I recovered some chips with one of them being TDA1311 which is a DAC. It is an eight pin dual in line chip with seven active terminals and one not used. Browsing its data sheet I found there is a striking similarity to DACs discussed in these forums. My pertinent question: Is this chip still useable, for instance, to implement a USB DAC?

TDA1311 datasheet

I haven’t done any audio stuff in several years so I’m cleaning out my garage of all my stuff. Would like to sell or trade it for a pair of nice bookshelf speakers.

I have:
- big aluminum heat sinks (2Ea x 30” long x 6” x 1 3/4”)
- 2 toroid transformers. I forget the specs but I think they were right sized for 150W amps... but they were for 240V primaries...
- 2 x 300W DIY SKA amp
- 3 way Biamp speakers (don’t remember the drivers, but they were good quality - not premium, but good. 1” dome, 4” and 12”.
- RL 24 dB active crossover (for the speakers)
- peavey CS 800 amp

I probably have some other stuff that I’m not thinking of at the moment. Ideally, someone local comes and takes it all.

I'm getting a parts list together for a headphone amp that I'm working on and would like to incorporate an audio source ground loop isolator using a couple of matching transformers. The circuit is simple enough but I'm seeing several different impedance recommendations. Generally 600 and 10k ohm. They have some reasonable wide frequency response models over at Edcor in several impedances. Any of you done this? Can anyone recommend a proper impedance for use with a tube amp? I'm using a 6DJ8 on the input and I don't know what input impedance it likes to see (or how to calculate it for that matter.) It'll take months for them to get here so if I find out I ordered the wrong transformers, I'm probably gonna break down and cry... I'm also hoping that this will solve a little problem I've run into. My phone has no headphone jack. I have gotten two of those USB-C to headphone dongles with the integrated DACs in them and they positively REFUSE to turn on unless actual headphones are plugged into them. No aux input works, either on my headphone amp or any other commercial equipment that I've tried. I'm assuming that the DACs in those things are looking for an inductive load before turning on to protect themselves or something. I'm just not sure. Anybody have experience with that?

Using my Kelvin micro-ohmeter which which I believe bypasses contact resistance in it's measurements, I measured a 16 gauge 312 cm wire (loopback) at .096 ohms (pretty close to what would be expected). Measuring with Limp as a loop back, it came to .51 ohms; presumptively due to contact resistance inclusion of .414 ohms. So, in setting the Cable Compensation Resistance in LIMP, I am wondering if I should include the contact resistance or not as contact resistance will exist in any design?

I have designed many systems with outcomes that I have been pretty pleased with but I never really thought about this before.

Isn’t there a risk of voice coil rubbing in the Alpair 5.3 since there isn’t a spider?