Here some pictures modding Phono Preamplifier

Dynavox TC20.

In this forum there is a modding of a similar but different version:

https://www.analog-forum.de/wbboard...gegen-ear-834-clone-oder-david-gegen-goliath/

In my Preamp is a NE5532 op amp instead of the 4558.

As this component is good enough my mods only concern putting to the electrolytics foil capacitors in parallel.

One cap is across the rails of the op.

I think I will buy another preamp of this type to make a listening comparison.

And later putting an LM4562 in it. The 4562 is an op which I liked a lot in an old Nad CD player and made it sound very good.

If I would like to transform the NE5532 to class A.
From which leg(s) of the op to which leg I would have to wire a resistor of what value? 10k?

I did not change the wall wart of 12v.

Would a power supply of 15volts instead of 12 volts bring more dynamic sound or dynamic headroom? The caps are all rated 25volts.

The max power supply for the NE5532 would be 18volts? Or can it stand even more?

Hi-

Have been playing in the Roon/Raspi streamer world and having plenty of fun with that. Am only proficient to a "simpleton" level as a tech, which is why I'm posting for helllllppp!!

Here's the current project from bottom to top of the Pi stack:

Ian Canada UCPi power supply-powered via USB-C using a Nirvana switch mode power supply
RasPi 4 rev B
Ian 9038Q2MPi Dual Mono Plus DAC HAT with the ESS controller of course
Ian OPA861 I/V output
To get started, I ordered a generic little 3.3/5v dual regulator board from Amazon to supply the DAC HAT and OPA861, powering the regulator with a 2.5 amp wallwart. That got the system working, sounding pretty nice while I saved up to start building up to better power supplies. It is likely this will get built into a nice case, it is enjoyable!
_____________________________________________________________________________________________________________________________________________________________________________________________
So now I finally got the Ian Dual Linear Pi MKII linear power supply powered with a Triad 2X 6vac 100va toroidal xformer. When I mocked up that upgrade was careful and methodical to match my skill level:
First wired the Xformer primary and tested the secondary winding outputs to be sure they were correct at 6vac X2.
Next connected 6vac to the inputs of the Ian Dual LInear unit and made sure i had the correct 5v outputs and polarity of DC voltage.
Then modded the jumpers on one Ian Dual Linear board to 3.3v and tested that power supply output for correct voltage/polarity.
Finally, connected the Ian dual linear PS up to the rest of the stack; the Ian DAC HAT gets all three of the single 3.3v power ins chained together with jumpers and powered by a single Dual Linear PS board. The OPA861 gets its 5v +/- from the other board of the Dual Linear PS that's configured to 5v. I did not connect the ground terminal of the OPA861 board to anything as there is no case yet.

That was last night, and as I fired 'er up in anticipation to be hearing some audio improvements from the better PS, just got only loud hum as the output of this RAsPi player stack!

So far, I have tried connecting the Ian OPA 861 ground terminal to the ground of an AC outlet and it still hums the same? So unhooked that.

But this is interesting and might mean something: I left the Ian Dual Linear PS board configured for 3.3v powering the Ian DAC HAT. But on the Ian OPA 861 I disconnected the dual linear PS and am powering its 5v with the Amazon regulator/wallwart. Powered like that, the streamer works normally with no hum, just nice music on the audio out. Can anyone enlighten me on what I missed, please?

Hi I need schematic for fender rumble 25 v3 with TDA2050 output IC
Anyone ???

for sale pair ESL63, defective due to some shaking during house moving. repairable or gor parts only. location spain, alicante

For Sale Prof built high end stand mounts using seas exotic

Bought these a few months ago with the intention of keeping full stop, but I cant help faffing.
Built by a cabinet maker to amazing quality of cabinetry, those angles!
They are made with birch ply and several layers thick.. These are a 2 man lift!
They use the seas exotic drivers, over 2k for the set.
High grade components on the xover using the audionote ANE design (not my work) with mundorf caps, and foil inductors.
The stands I made only a few weeks ago and need finishing. I used our cnc machine at work, so they are perfectly angled and cut etc. Same for the grilles I made.
The velcro dots on the cabinets can easily be unstuck if you want a nice clean facia and no grille.
I would estimate the build cost at around 4 to 4.5k!
Some of the best detail and effortless sound I have head from a loudspeaker. More of a weighty studio monitor I would say, with effortless low end.

Sell for £1, 500.00

Swap for other hifi, anything considered, single ended valve power amp, turntable, MC phono stage.

Collection only of course..
Bring some thick blankets.
Obvs I can help load.. Believe me these are incredibly heavy.

Hi, sorry forgot to include dims.
Height 660mm
Width 440mm taper to 290mm
Depth 500 top and back also tapers
OA height with stands 990mm

Hi I am about to build some dipole subs for my Magnepan 3.7i.
Going to use two SB34NRX75 in a U frame per side.

Should I use miniDSP 2x4 HD with a stereo amp or buy the Hypex FA501.
I like the Hypex FA501 because it has high level input and everything is in one packages.

But again, how easy is it to program?

What would you recommend?

I need a k3677 transistor but I'm not getting it., Can I use k3667 ?

Hello brains trust…!!!
Has anyone tried different drivers in a BK-12M enclosure..?? Apologies if this has been discussed before but every time I see a thread it derails into a sword fight…!!! Just looking for simple advice like; yeah I tried this driver and it was really good/crap.! Being driven by a Triode Lab el84 set/ffx in a small room 4.5x3.5.

Cheers.
🔫

Muses72323 volume PCB
30usd+shipping 5usd by ferry(takes around 2-3 month)

https://nw-electric.way-nifty.com/blog/files/muses72323vol_r11e59b9ee8b7afe59bb3.pdf

https://nw-electric.way-nifty.com/blog/muses72323vol.html

Hi all,

I have a 4 channel amplifier, which has low output on the 3rd channel. there are no shorted components.
Each channel has 2 N-channel mosfets - FQP33N10. I haven't come across an amplifier like this before.
could it be a pre-amp issue or dirty switches?

Something that always bothered me about the Keele CBT arrays, is that the loudest drivers in the array sit on the floor, and the quietest drivers in the array are at ear level!

This always seemed to make no sense to me, and in all of the CBT experiments I've done, I've shaded them so that the loudest drivers are in the center of the array, like every other array type does.

This afternoon I was running some sims in Vituixcad. When using the array generator in VituixCad, it puts the mic at the center of the array, by default.



But note that the HOTTEST driver in the array sits there on the floor.


Here's how things look with the CBT array, with the mic sitting on the floor.

These results made no sense to me; why is it louder OFF axis than ON axis?

I went digging through the help manual, looking for some type of solution, with no luck.



Here's how the array performs if you move the mic to ear level, or 36" / 914mm off the floor. Directivity control doesn't go as low, but now the polars look correct. In particular, it's louder on axis than off. (Note that we've changed the "on axis" point of reference to be 914mm higher than it was before. IE, we moved the mic to ear level.)

After pondering this for a little while, I think I figured it out:

Keele describes "halving" the array as a situation where the floor reflects the array like a perfect mirror. I'm not convinced this is the case; I haven't seen any data to support the idea that the floor can perfectly mirror what's above it.

But I do think that the backwards tilt, caused by the curvature of the CBT array, is moving the listening axis UP.

I've posted the data; this next part is a bit of speculation:



If you look at the profile of a CBT array, it points UP about twenty degrees. If you listen at a distance of three meters (fairly typical), that means that the focal point of the listening axis is 1.85 meters above the floor if there is no shading. IE, if the CBT was just a curved array with no attention whatsoever to the shading, you'd need to be standing to hear the maximum SPL and smoothest possible response from a CBT the size of a CBT24 (five feet tall.)

https://www.parts-express.com/Epique-CBT24-Line-Array-Speaker-System-Pair-301-982

All of us have messed around with the balance control on a set of stereo speakers. Turn the knob to the right, and it tends to 'shift' the soundstage to the right.

To an extent, I think the shading on the CBT is doing something similar:
1) The curvature of the CBT is aiming the listening axis up in the air. For a CBT24, if it wasn't shaded, the listening axis would be 1.85M off the floor, or about six feet tall. If you were seated, you would be outside of the optimal listening window

2) But by shading it, it has the effect of virtually moving the listening axis DOWN.

I never understood the scheme until today, but it's pretty clever if you think about it in layman's terms:

1) If you are listening to a CBT that's two meters tall, and you're seated and your ears are one meter off the floor, you have two things canceling each other out: The tilt-back of the array is pointing the listening axis about a meter above your head, but the shading on the array is dragging the listening axis back down

2) If you are listening to a CBT that's two meters tall, and you're standing and your ears are two meters off the floor, you have two things canceling each other out: The tilt-back of the array is pointing the listening axis right at your head, but the shading on the array is dragging the listening axis back down. If the array wasn't shaded, this height would be louder than any other height, because the array is physically pointed at this height. But the shading is 'pulling' the axis back down towards the floor.

3) If you are listening to a CBT that's two meters tall, and you're laying on the floor and your ears are just above the floor, you have two things canceling each other out: The tilt-back of the array is pointing the listening axis at a point two meters above you, but the shading on the array is dragging the listening axis back down to where you're ears are at (the floor.) If the array wasn't shaded, this height would be quieter than other heights, because the array is physically pointed at a spot two meters above you. But the shading is 'pulling' the axis back down towards the floor.

With all of that in mind, it seems like one might be able to simplify a CBT array by using a plain ol' flat baffle, but tilting it backwards and shading it. This should improve the WAF of the speaker, while also making it simpler to construct.

Some additional notes:

• In the real world, if one is 'tweaking' a CBT, it may be useful to tweak the resistor values for the shading so that the curves are largely equal at various heights. IE, if you look at my shading, I chose the values using "optimum" values for the sim. The sim doesn't factor in the impact of floor reflectivity and the furniture in the room. In the real world, one could probably improve things quite a bit by tweaking those resistor values so that the measured output is consistent at different heights. By doing it in your room, you're compensating for what's in the room. This isn't like a typical crossover with inductors and caps, where modifying values has a cascading effect on all the crossover points. Because these are just resistors and for the most part all they're doing is manipulating the amplitude of the various elements. Easier to do this with DSP of course, but that would require a lot of channels of amplification.
• In the sims above, I'm using eight MCM 55-1870 midbasses. That's why the response above 3khz is all over the map; I'm not using the ultra wide bandwidth and small diameters drivers from a 'real' CBT. (My plan is to add a tweeter here, BTW)

I got this unit for free, but it doesn't work... I already changed a semiconductor fuse on the PS board, as the analog +12V rail was missing. But this didn't cure the following two problems:

- Something is wrong with the drawer control. It looks like the controller doesn't realize the drawer is in its end position, because the drawer opens and closes all the time without pressing a button. The switch on the drawer is ok, though - I checked it. To make the player try to read a disc, you have to switch the unit off and on again in the moment the drawer is closed.

- When initializing, the pickup moves back towards the center of the disc and the focus servo seems to work. I held a disc above the lens and carefully moved it up and down - the lens followed. However, the spindle motor starts spinning like mad - no disc is recognized.

There are no pots in the unit except for playback power, CD-R record power and CD-RW record power.

Can anyone experienced fixing CD players help me with this one?

Thanks

I did a search through the threads and didn't see this specific topic addressed, so if you know of a thread that already went through this, I'll accept the shame of being inept at internet searches. Anyway, here goes...

I'm putting together a simple 12AX7-based RIAA phono stage with a source follower on the output. This is the first phono stage I've attempted with lots of SPICE and PSUD2 modeling to guide me. I'm set with the audio circuit, and had a PSU all rigged up, but the vintage Dynaco PAS2 power transformer I was going to use mysteriously died.

I have a Broskie passive power supply stuffed and tested, using UF4007 diodes and a CRC of 47uF_470R_47uF. After that I was going to use an LR8 per channel for rectified plate supplies to the audio PCBs.

The Dyna transformer would have given me about +360VDC, and the audio PCB was designed to get +320VDC. That left me with lots of volts to drop across the LR8 regulators. However, the most DC voltage I'm going to get from a 500VCT 40mA power transformer is maybe +330VDC, or more likely +325VDC.

To change the PSU design so that it mates well with the already stuffed audio PCB, I need to do something that drops very little volts. It looks like the LR8-based PSU I had in mind is going to need to drop at least 15V, or 20V to be safe. That reduces the available B+ to the audio board to down near 300V. That would be OK, but I did design it for 320V.

I did a little more modeling of the audio PCB and PSU combined, and found that if I can get all the ripple reduction I need by adding an RCRC network of 220R_800uF_220R_800uF after the Broskie power supply PCB. (I have a bunch of 800uF 330V electrolytic capacitors I was given some time ago.) PSUD2 predicts residual ripple will be in the microvolts.

So finally, the question:

What would be the disadvantages of using a 'passive' PSU employing these monster 800uF capacitors as compared to something like a single LR8 per channel, or a Maida reg set at 310V?

I figure that the impedances of a 12AX7-based circuit are high (rp of about 75k ohms), so an ultra-low impedance PSU is not going to be all that beneficial, right?
--

Well, anyone at least partially partial with my omnipresent babbling, knows about endless series of M2 derivatives, I made sorta recently
All of them having M2-like Front End (my biggest Fetish), so entire voltage gain got from autoformer, so no (overall) NFB involved
Also - all of them having second of my recent Fetishes - Square Law OS

Ok, that is line of unnecessary long line of M2 derivatives, difference amongst them being that each is having different quirk of OS parts

Then came next fixation point... when I concocted FE for Babelfish XA252, biggest part of invention was proper name for same FE - Plethora of Pinjatas ....... so I ( naturally) came to idea of making second totally unnecessary line of derivatives, now having Plethora of Pinjatas FE, and simply varying already proven SL OS iterations

This line having slightly different ( sorta mirrored/flipped/downundered/whatever) biasing mechanismus, comparing to older specimens, this one directly taken form Babelfish XA252
Comparing to older ones ( having opto between Mosfet Gates and fixed resistors from rails to gates), there are current mirrors from rails to fixed resistor(s) between Mosfet gates; result is better Iq behavior in domain of rails change, same as better Iq behavior in thermal change domain, and also firmer relaxation factor (Iq stability in dynamic domain; think recovery time if change occurs with long large signal)

Anyway, let's ignore Babelfish XA252 as first one, declare SissySIT P (P suffix for Plethora of Pinjatas family) as first one

Am I happy ...... yes! (this one done, so I can think of working on next )

Confirming same amp sound character, for amps made without NFB and with Autoformer gain and amps made with sorta heavy NFB and active gain ....... well, not exactly a novelty per se

this post intentionally made pic-less - in case of later edits, lesser mess

I am planing to build the mosfet follower on esp site (Project 83) , as per the suggestions on that page the pre section will be powered by the DOZ Preamp .I want to incorporate Amp , Pre , and capacitance multiplier on a single PCB and i have some doubts on the implementation . can i power the pre section from same supply section of the amp ( from capacitance multiplier ) or do i have to use the preamp power supply specified for doz pre on esp will this have significant effect on sound quality ?. If i had to add a volume control should it be added in between the the pre and amp or before pre section ?

Hello,
After repairing and overhauling a C-2102 preamplifier, the following error appears.
The relay LRL 1, which is connected to the connector with pins 31...32...33 on the power supply board, switches on and off rhythmically.
All components in the circuit branch on the power supply board are intact and as soon as I remove the on/off LED from connection 34...35 of the power supply, the preamplifier works perfectly.
Can someone explain to me why this error occurs and perhaps give me a tip as to where I should look? Thank you in advance for your effort and I hope you all have a nice day

Hi,
I'm in the process of repairing damaged pot from Parasound new classic 2100.
looks like a 50K - MN style taper pot (see attached picture). My problem is that I have not been able find a replacement at for example RS-components.
Anybody know the source of a good quality replacement? What would part number for e.g. Bourns, Vishay or ALPS replacement be?

PS: Anyone have the schematic for this pre to share?

Thanks
Lars

Microaudio Cobra S1 SMPS +/-63Vdc rails, 15 Vdc Driver Voltage, +/-12Vdc Aux Voltage. Mundorf Caps installed Primary and Secondary.

1 Available - $400 USD.

Thanks

My valve pre amp makes a tick or tick-tick noise like a spark on start up, not through the speakers just from inside the case, can't really see/hear where. The question is a general one - for example do capacitors or diodes sometimes do this when they are starting to fail? The preamp works fine, BUT it sounds like the start of something to be concerned about?

Any ideas?

Hi guys,
I'm going to do the power supply from this blog, but some values are not visible well.
Anyone with a guess?
Regards!

Hi, i am trying to help my brother design a sort of joining/breakout board for some sort of 8 channel audio cable.
Basically we need to join the end of the cable to other cables and we tought the easiest way was to use a small pcb that has two rows of pads with short traces conecting them, but we heard that the pcb traces would have crosstalk if traces run parallel to one another.
I am wondering if that would be a real issue for this use case. The pcb would have ground plane in between all the signal traces.
It would be used for line level signal.
There is a pcb photo in attachment, the board size is around 50mm x 11mm
Note that the pcbs are not final, this is just some testing and messing around

Back in the eighties and nineties , Elektor and some others were my beacon for ideas.
After 2000 , those others disappeared and it was slim pickings at Elektor.
While it was fun back then making things like temperature and humidity meters or clocks,
these days our oriental friends make such things with a custom LCD in a nice little case for 2 to 3 euro's .

I have all these components , but no idea's for a worthwhile project. You just can't compete with what is already for sale and very cheap.
I made my HPamp and using it . A USB dac is too delicate for me , better buy a prebuild DAP that has a USB dac. That's about it for audio DIY.
How many amps can you build AND really use ?

I like to do something more with LEDs or solar panels , but also there , you just can't compete with prebuild "oriental" stuff.

A couple of weeks ago , I bought a 25.000 count MM with extra functions , 25 euro .
If Fluke made anything near this , it would cost 500 to 800 euro or even more. Not that I would make my own MM.
Oscilloscopes too are getting cheap , this one for me 122 euro's for 100 Mhz : lazada (right click in your browser to translate).
But with no projects to measure , what's the point of buying one?

What is still worthwhile to make and are there websites like DIYaudio but for other than audio ?

I have always used regular wood screws, but Madisound sells a 6-32 x 1” Socket Head Cap Screw with T-Nut:



Opinions?

Thanks,

john

I have been reading a lot about different sorts of tube amplifiers the last couple of weeks in an effort to gain enough knowledge to design my own at some point.

The Torpedo 3 topology i found particularly interesting compared to a lot of other designs. I am however at a bit of a loss when it comes to the CCS's. I have an idea that the output CCS might be a cascode depletion-mode MOSFET design, as described by Walt Jung in the Audioexpress article, but i'm not sure.

Does anyone know the exact circuit of both the output CCS and the tube CCS?

I need to limit the output current depending on the Vce of output transistors as is done in several chip amps. Is there a working example or once again I must reinvent the wheel?

Hi, Im needing some help after a recap Ive recently completed on the Technics SL7. When I purchased it everything worked and functioned correctly.
After doing some research on this model it was common to have very leaky capacitors due to age.

So I had a peak at the pcb and it showed many capacitors with green corrosion on legs.

Work completed -

• All electrolytic caps replaced with exact same MF though sometimes replaced with higher voltage rating
• re flowed a few solder joints
• De oxit all switches and plugs

I have gone back through all of the work I did and confirmed the correct polarity of caps and looked for potential solder bridges. (all looks good)
All connectors are plugged in properly

I noticed a cracked solder on the IC1 (voltage reference) after re flowing join still no power. Is it possible that this has caused damage somewhere else when powering up?

I tried plugging in the 12v outlet also and still no power

Any ideas on where to start with this issue?

Thought someone might be interested

Hi folks,

I'm moving overseas and wondering whether the 9505 supports internal reconfiguration from 120V to 240V mains. Anyone know off hand?

Thanks,
Paul

This is interesting, though old-timers likely know much of the content (partly through Bob Pease's writings). If you can't watch the whole thing, the more interesting (imho) parts start at about 10 minutes in, with Bob Widlar's first chip designs. it shows the infamous "message to the competition" ad, but I'm a little surprised there was no mention of Bob Pease.
Login to view embedded media

Hello,

I am on the hunt for an ESS 200 and Preamp schematic.

I did find the Preamplifier "brochure" on hifiengine that contains an article (in French, not my native tongue) that contains a brief schematic.

@Nelson Pass it was suggested that I try reaching out to you via this fora. Any help is greatly appreciated.

Thank you.

I owe NickS (Ugly Woofer) for the light bulb on the name. He said they 'resemble putting a ship in a bottle'. Mix with Battleship, and voila!

So, if you thought the Purveyor were small, these are shoehorned into HALF that volume. You likely now think I've sincerely lost my mind. These are the smallest 3ways I've both seen and heard (of) in DIY circles. The Purveyor were 5.25"/2.5"/1.0" arrangement, and the new 'ships are 4"/2"/0.75". There is no way a 5.25" woofer would fit and perform well in a total of 3.5 ltrs, nor will the drivers fit on the baffle without using a 4" or smaller woofer. If I want the bass extension, a 3" with good bass performance would be too low in sensitivity for my requirements, so a 4" it has to be. Next problem is that the number of 4" with great bass performance is even fewer than that of the 5.25" pool of options. I settled on the Peerless SDS 830855, $19 at PE, and a supposed 86dB sensitivity. The obvious next choice is that of a 5.25" PR to align the stars for the best maiden voyage into bass dredging. (Looking around, I feel that the Dayton TCP115-4 could be a viable woofer substitution with some xover rework, as long as it fits on the baffle.)

So, putting this info above into practical use, the mid I decided on is the Audible Physics 220CP1 8ohm from Newark/Farnell for $22. It's a carbon paper cone with an aluminum dustcap, cast frame, 86dB sensitivity, and a large Neo motor. Being that Chuck (isaeagle1031) and others have really liked the AP stuff, so I didn't even second guess my choice at the cheap price per. I had to try it after seeing it in Brandon's thread a little while ago. I fiddled around with 4-5 different chamber arrangements empirically modeling and physically testing them until I came upon another of my 'ice-cream sandwich' type alignments, or Multichambered Aperiodic sealed; AKA MAPD from Northcreek fame. Being a 2", and being primarily used from 700Hz+ as an estimate, the amount of volume required is small. However, the Fs magnitude and frequency is fairly high and could stand to be minimized a bit to aid in xover simplicity and damping of the rolloff. Using a 2" PVC coupler and endcap, a 1.5"-2" adapter, 2 equal pieces of Bonded Logic or Ultra Touch, a ring of wool batting, and a bit of E6000 adhesive; sufficed for a 0.13 ltr chamber.

Further on the boxes... Being of minimal midrange volume, this lent the woofer volume to be ~3.2 ltrs. Using the DSA135 PR without added mass models to Fb/3/10 of 60/68/48Hz, or a very gradual rolloff. Trying to conserve sensitivity, using a steel-laminate coil creates a bump in response around the Fs of the woofer of a dB or two. Then using a 730uF Passive Assist capacitor in combination with the highish Fs and the higher Q of a vented box, while gaining another order on the rolloff, actually also extends the lowend a smidge here. (I have a HUGE box of 330uF polarized caps, and I have been making large NPE caps with them for awhile now.)

I am using the Dayton ND20FA-6 because I have them, and it fits atop the mid on the baffle. They are tiny, but look big on these small speakers. The main positioning of the drivers on the baffle actually involves the midrange chamber as the most influential information. Acoustic offsets are at 2" from midrange to tweeter, and 4" from midrange to woofer. Unfortunately, this also means that the truncated Peerless MUST be mounted vertically to get everything to fit.

The xover as modeled and refined represents 17 individual components. I can hear the gasping and see the whites of your eyes now.... In this portion I am using the smaller and cheaper parts I've acquired over the years, like 22AWG coils for the tweeter and midrange shunts, small mylar caps, and as few resistors as possible. "How you gonna fit all that $#!+ in that tiny box, dude!?" was the usual reply in conversation with the closest of you.
Well- it ended up requiring a 3D xover pegboard assembly. I've thought of doing this before, and have done daughter boards before a few times but never to this nth degree. It almost operates as a brace that press-fits vertically inside.

Now, a lot of you are likely thinking, "Why!? would you have a 3way with a 4" woofer?" The initial goal was to use the AP mid or any 2" mid effectively. Going further, the tweeter is good to 4kHz before HD rises. The AP has HD above 1% below the 750-800Hz region. The 830855 has dominant 3rd order HD above about 1.2kHz, even though it does not rise above 1% in amplitude. According to these frames of reference, it makes sense why the HD would be lower or better for these particular drivers utilized together.

The mid takes #4 flush-head screws as the mounting holes are beveled. I bought some torx head "for plastic" screws that worked really nicely. The woofer/PR have #8 torx sheet metal screws. The tweeter is press fit and sealed with E6000 on the back. Woofer inside edge is beveled. To speed up the process, I used a self-selected hole saw set that I accumulated last year for Christmas. The largest is a 4.125" diameter for common tweeter faces. Cutting the perimeter of the rebates is the hardest part, then the remaining area can be removed swiftly with the trim router. It takes less time in setup and making the cuts than a full router solution for me. However, a router rabbet bearing set is also a valid counterpart to the hole saws.

The finish is 2-3 coats of Watco Danish Oil, then Minwax Golden Oak stain. Being the grain is a bit open, I did something different this time. I used Permatex black silicone to cover the surface, and then slowly wiped off the excess. After that dried, I steel wooled the surface to remove the crumbs and excessive bits. Then a coat of polyurethane finished the front and back off. The chatoyance is pretty nice, and I really like the edge look. The main box section is built with pre-formica'd 3/4" particle board. I used full mitered corners for the finished assembly, and coated with epoxy for strength and durability.

The inputs are rear mounted binding posts that did not have the front nut to clamp down. I grabbed a bag a couple years ago at a DIY event. Basically, I drilled a 19/64" hole, recess the entrance from the rear so it's closer to the front, and lightly beveled the front entrance. Then I sealed it with E6000 to be air tight and keep it strong. I even made/altered a custom socket to drive them from an 11/32" Craftsman deep well socket as I have a LOT of them. I apply solder to the tips to pre-tin them, reheat and insert the wire. Why the 3 terminals? I planned on measuring the difference nearfield with and without the 730uF in play. The Blue terminal is direct to the lowpass coil and bypasses this cap whereas the red terminal is input to the 730uF capacitor bundle. I can just move the banana plug and use it the other way.

How do they sound? These are actually really impressive WITHOUT the big cap. With was okay, but has some insertion loss for sure.
I could take them to -10 on the preamp to where they started to complain a bit without the cap engaged. There doesn't seem to be much difference in spectral balance with the cap though. They really can kick up a storm in the bass too. For damping, I have a roll of wool batting wedged between the woofer and PR. The mids are really nice and clean, and the tweeter does an admiral job in its bandwidth with low HD to boot. I think the PR is barely capable of being pummeled by this Peerless woofer. It puts up with it, but likely to the peak of its performance at higher levels.

Tuning was supposed to be 60Hz in modeling, but measured at 50Hz. Not really sure how this happened. I only have the dinky supplied washer and bolt that came with the PRs attached to the mounting hole. Maybe the Mms on these units was higher than spec, or the volume somehow is larger than modeled- and I know if anything it's less volume. This yields an F3/10 of 80/42Hz, and that is not really all that bad. Bass sounds great for a 4" design.

Initial measurements showed a dip at 718Hz and 150Hz. I knew the 150 was likely floor bounce, and ignored it. Modelling the highpass cap doubled indicated that the higher dip might fill in, and it was still present off axis. After this complying modification, I measured higher from the floor, and the dip shifted to 525Hz. The 150 dip disappeared. However, the HD is still good and the upper dip is gone. Fullness was perceived as better on the bottom of the midrange than before. Xover points became 900/4k Hz.

I'll have to separate this in a few posts to get it all up here...
Thanks for looking!
Wolf

Edit: The purple dims in mm in the drawing are for supposed acoustic Z offsets. These do not represent the dimensions of the drivers.

Has anyone tried this? The Qts is quite high, so that’s good. I’m thinking of putting it on a 12” or 18” wide by 72” long baffle, the driver positioned at approximately 40”, my ear height above the floor while sitting. How low could I expect it to go?

Hi, is this a opamp that are good for audio?

Frank

Hi everyone,

I'm working on a project where I'd like to build a device that can record audio from a Bluetooth source, similar to how Teenage Engineering's OB-4 works. In particular, I'm interested in understanding how I can capture and record audio directly from the Bluetooth signal, rather than using an external microphone.

Here are some of my specific questions:

What are the best Bluetooth modules I could use to receive a high-quality audio signal?
What type of microcontroller or DSP would be best suited to process this audio signal?
How can I store this recorded audio on an SD memory or other type of external memory?
Are special ADC/DAC converters needed or can I manage everything digitally?
What are the best practices for programming the firmware that will handle the recording and saving process?
Any help or guidance would be hugely appreciated. Thank you so much in advance for your time and expertise!

I’m curious what you guys think about the idea of installing a pro audio dsp into a 12v car audio system?
I’m aware that many companies out there have been making car audio dsp’s for years BUT I work as an A/V tech and we use either a biamp nexia, audia, (both older but Very capable and Cheap) or a tesira dsp in most every setup we do. (Mostly churches, sports bars, banquet halls etc.)
There 110v ac out of the box but that’s just converted to 24v dc as soon as it’s plugged in so do you guys see any reason I shouldn’t get a decent 12 to 24v boost converter and use something I can get for basically free and has amazingly capable software??
Anyone can get a rack Mount biamp nexia dsp on eBay for $30-$50 and the possibilities are almost endless. An Audia or Tersia would even add AEC capabilities for phone calls if you wanted to go all out I would assume.
Anyone have any experience with Pro Audio installations into a 12-24v dc system?
I’m on a budget but unless I’m missing something it sure seems like an affordable way to do what would cost over a grand for pretty cheap?? Idk maybe I’m crazy

Hello,

i am Hannes from the little town Mooskirchen in Austria.
After a long time reading here about very interesting stuff was the logical next step get activ in this forum.

To hear music was everyday my greatest hobby and with the buying of a own house the chance where in eyesight to install bigger speakers 😍
I like to build my speakers and electronics by myself.

Greets Hannes

Hi All
I don't know if I am late to the ballgame but I just found a free software for plywood layouts. You just tell it the size of you material , the panels you need, the width of your blade and it lays them out including grain orientation and many other features.
I have absolutely no affiliation with this product.

Just search Maxcut, There is a nice youtube to show how to use it.
Jeremy

Hi,

I am looking for someone that corrects or redesign a simple pcb from an schematic.

Basically, the board is a kind of breakout board for a TDA1541 dac. This board is installed in the TDA1541 socket and:

1. Routes the TDA I2S input signal to a XH connector. I have placed an isolator to avoid any unwanted ground loop. This isolator is powered with a dedicated psu (independent secondary) and a dc-dc isolator to power both sides.
2. Provides three UFL connectors to connect an I2S signal into the TDA1541 which is installed in the board.

Using this board I can install a FIFO in any TDA1541 DAC without modifying or removing any component. I have build a prototype and it works as expected so I would like to build it seriously but do not the skills to do so.

I have an EASYEDA project I can share.

best regards,
jm

Sale 1 Odroid C2 50 Euro. and 1 Odroid C1 40 Euro.,Good condition, use 1 year in audio file server.

Hi,
I've encountered a problem with my Neutrik A1.
The output of the amplifier is working only on the (2) +pin of the XLR and the (3) -pin is presenting a very low voltage square-ish wave.
As a consequence of this, all the measurements are 6dB lower than expected.
I looked everywhere but couldn't find a service manual or schematics.
Is anyone able to provide any help?
Thanks in advance!!
Michele

Looking to find a nanodigi 2x8 so I can try out activecrossovers. Not really interested in a 2x4HD and can’t justify the price of a FLEX until I’m sold on the tech.

Dear Fellows Audio Enthusiasts!

There were several reports that our VCX MUSES volume control boards exhibited spontaneous volume jumps to 99 or a 100.
Upon thorough investigation, we found that those jumps were caused by some silicon issues, and developed a workaround that eliminates the problem. It was a lengthy process and we greatly appreciate the contribution of the DIY community members to that work.
Please note that VCX units shipped after July 15 2023 are free from that defect.

Please note that not all the VCX boards shipped before July 15 2023 were affected by that problem. Nevertheless, we take seriously the quality issues, and we sent personal emails to each and every customer, who purchased the VCX that may be affected by the volume jumps problem and offered them to return the boards for a free firmware update. As a token of appreciation of those customers loyalty and patience with each reprogrammed VCX unit we provide a unique discount code to purchase our products.

If for any reason you missed your RMA letter in the mail, feel free to contact the company for the free firmware update.

Thanks again for your continuing support!

Lenny Novikov
Academy Audio Inc.

Hello!

I'm on a quest to build an active sealed 3-way using the sb acoustics ceramic line of speakers (5 inch mid and 8 inch woofer) and just today placed an order for the 5 inch augerpro waveguide for the sb26cdc.

I had the crazy idea of using a plastic draining tube made for placement in the ground as an enclosure for the mid? This would make the build much easier since I am aiming for a more compact design to be used as studio monitors primarily.

I have tried researching the topic and it seems like it might be ok?

Here is a link to the swedish website of the tubing in question https://www.hornbach.se/p/markror-pipelife-pp-sn8-o200-x-1000-mm/10601365/

It says polypropen which i guess is polypropylene in english?

So what say you? Does it work or is it ill-advised? my thought was a tube running the entire length front to back and then stuffed, maybe gluing a bunch of bitumen pads around it in an effort to damp it?

I'm looking for 4 ea, ESL-63 mid/treble panels.
Defect no problem, will consider buying complete steakers if price is right.
Preferable EU or continental Europe.

Jan

Dear Sirs,

I bought from eBay a functional Rane RPM26z processor, except it's password protected when I try to access it by it's control app DragNet. I tough that's not a problem, just have to reset it, remove a button battery or rewrite the FW, but seems it's not that simple. What I found:

"For maximum security all passwords are stored in a protected area of non-volatile memory within the RPM device itself. Updating firmware does NOT erase these passwords or disable security in any way. Please keep track of all passwords. If a password is forgotten or lost you must contact Rane tech support for information on restoring the password and gaining access to the device. There may be a charge for this service."

I sent message to Rane Commercial about the problem --they were taken by InMusicBrands in 2016-- and they replied:

"...unfortunately this item was discountinued long before we took over Rane and sadly any available documentation we have does not mention any passwords for this device sadly. This process must have been something that the previous support team provided however we are unable to confirm for sure.".

I've got refunded by the seller (obviously he doesn't know the password) but now I am standing in front of --otherwise-- a nice processor and thinking how to break in. The thing should support brute force password attack, has no unsuccessful tries limit or timeout and I want to know if anybody have any better idea what to do? Many thanks in advance for any suggestion.

Regards,
Dorin

Hi there dear members!
I have bought me a Krell KST 100 amp and im curious if there is anyone out there with the information about the voltage settings on this one??
I do have the exploded view of the amp but there is nothing that tells me how the voltage is changed. I would be grateful to get some help on this one!!

Tested 102/102, 102/101 on a tv7. These have the three rivets on the plate. Comes in original tethered Sperry boxes dated 9/52. 70.00 plus shipping and paypal fees if used. I prefer friends and family or personal check. I sold a pair on ebay yesterday and they charged 14.00 to sell a pair of these for 80.00. Getting older and tired of making other people rich.
Thanks OLD BIG

Hi all,

i am using some old second hand drivers to try and make a car speaker system. I have a 10" central driver with two 4" mids and two tweeters. i am unsure on how to decided on an amplifier circuit to go for, is it worth splashing out on an expensive one or are the cheaper ones with less inputs still going to work.? i also wondered if anyone had any suggestions on how to build a crossover circuit or will it be significantly easier to buy some?

Cheers

I have available a small quantity of PCBs and Front panels for building the accelerometer preamplifier as described in my article in Audioxpress June 2011. You can find the article online if you have missed it (Test Your Speakers? Performance with this DIY Measurement System | audioXpress).
If you are interested, send me an email: gntanavaras@gmail.com

Hi folks,

The title is my question.
Small batch (up to 10 sets) is preferred.
As pretty flexible with design, core power size can be any from 40VA to 200VA
Any help?

Hi dear diyAudio community,

I use a Dayton DAEX32EP-4 exciter with a XY-502 Digital Power Amplifier and a powersupply with 24V and 1.4A. At the beginning everything worked out fine, but after using it for an hour or so the exciter started clicking. I also tried other exciters and the same happend. Does someone of you know what the problem could be? I have uploaded two videos to my drive which you can find here.

Thank you very much.

Best,
SonicDriver

I want to build my first diy speakers using a 2 way design and simple second order crossover. Why 2 way little speakers?
My listening room is not huge, so don't need really big ones.
I can't use loud bass because disturbing/shaking next door people. Finally also the "wife" don't want monster speakers and my listening preferences are not related to big-boomy bass at all.
I'm also starting the path to build a Master's Nelson Pass clone (the old Aleph 3+27), so not huge power, only pure 30 watts in class A (if God bless me letting me finalizing everything).

I'm sharing my first newbie insights and thoughts before proceed with the purchase of speaker components. I'm sure I can get some advice from seasoned speaker builders, advice on things I'm not aware.

My budget is limited, so my first decision was to use Wavecor drivers, cost contained but seems to be good ones, easily found in the European diy market and widely used as OEM speaker parts. The web page is also full of information.

First step.
In order to get some insights and inspiration I looked into different existent speaker kits using Wavecor drivers, having full information on the web, for example:

Wavemon 182, ported, using tweetter TW030WA09 + Mid-woofer WF182BD03
WaveMon 182
(I runned a simulation for this one too)

Loire Top, sealed, using tweetter TW030WA10 + Mid woofer WF182BD12
Loire Top

CSS Criton 1TD, ported, using tweeter TW022WA04 + Mid-woofer WF182BD10
SHOP | css-audio

Later I found a freeware Loudspeaker Simulator named VituixCAD by a genius guy named Kimmo Sauristo, and also found all the datasheets and full specs for simulation in the Wavecor page:
Database

After revising these above and other diy projects, and having all this in my mind, I selected the drivers with which I would like to bulild the speakers:

The Wavecor tweeter TW030WA11 and the midwoofer WF182BD10
TW030WA11_12
http://www.wavecor.com/html/wf182bd09_10_11_12.html

Found the midwoofer having interesting specs (low Fs and good overall characteristics) and being highly appreciated by many builders/listeners.
The tweeter was selected because the specs seems to be very fine compared to other Wavecor items. Selection was most a matter of intuition than deep knowledge.

As said, with full specs in hand (as found in the Wavecor web page), and after calculating a first voltage divider for the tweeter and selecting first filter values running on-line calculators, then I began to make many adjustments (playing up and down with capacitor, resistor and inductance values) with VituixCAD (was a very interesting experience with this marvelous tool) and got final setup..
The results are in the photos attached to this thread.

One photo shows the very simple crossover and component values, other the SPL simulation result with tweeter inverted phase/polarity and finally the filter graph showing a cross point at approx. 1898 Hz (this is not a problem for the tweeter, having a very low Fs of 410 Hz).

My question to any seasoned speaker diyer:
To me (a newbie) the results as per the photos seems to be fine. They reflect the drivers frequency and impedance bahavior. Is this trustable or I'm missing something?

Then.
My plan is to build a ported enclosure (not yet decided) between 15 and 17 liters, Fb between 37-39 Hz and F3 between 40-42 Hz. I know this will modify the SPL frequency response, but only in the lower first octave. I guess the results of the freq. response in the medium-upper register will not be affected.

Any thougts or advise?
I'm on a good road?

Looking for another pair of Scanspeak 10F/8414, ideally in the UK.
Cheers, Rob

I’m new here and joined due to a specific problem I am facing. I have an old out of warranty Tom Evans Design Microgroove.

It has too much (factory set) gain for the Rega Ania cartridge (0.35mV) that I intend to use with it.

Please see pictures of the unit inside. As I live in Denmark (EU) it will be very expensive and impractical to ship it to the factory for modification. Can any of you provide some brief instructions and/or a schematic of how to change the gain and any components needed? I completely understand that any changes carried out on the unit are done at my discretion and solely my risk.

Any input would be highly appreciated!

The most famous is probably the Eckhorn from Klipsch:
https://www.klipsch.com/founder
https://www.pinterest.de/pin/626352260655991272/
https://www.arkansasonline.com/photos/galleries/2019/nov/01/gallery-01-11-2019-16-41-59/
https://www.itishifi.com/hifi/klipsch-new-model-t
https://mysoundbook.eu/klipsch-klipschhorn-der-legendaere-hornlautsprecher-aus-den-40ern/
https://www.lowbeats.de/alles-nur-kein-********-der-markante-us-hersteller-klipsch-wird-75/
URL corrupted - keywords for Google (for getting this URL and information there): lowbeats der markante us hersteller klipsch wird 75

I am looking for the first released reviews from 40s and 50s.
Thank you for posting.
Any advertisements from those days in the attachment.

P.S.: this thread don't provide the wanted information:
https://www.diyaudio.com/community/threads/vintage-speakers-the-look.345351/

Hello, If I use a 500ohm resistor instead of a choke 120ohm/20H.

My voltage will get lower than if I used the choke, and I will get more ripple. It will also get even lower when the amp is under "heavy load" (!?sag) with the R than with the L. Ok.

But will I get more ripple when the amp sag (under LOAD) ? or just a lower voltage but with the same ripple than idle ?

Thank you.

Hi,
I have an issue with a Yamaha WXC-50 streaming client / preamplifier. It suddenly stopped providing output via line or toslink output while listening but was still controllable via MusicCast APP. After a few power cycles it finally stopped starting at all, red status LED is blinking 6 times. I checked the Yamaha service manual on hifiengine. The device has a self diagnostic function via browser interface but since it is no longer starting up I cannot use it. I tried the 3 "magic" key combination I am aware of to fix the issue:

1. Restarting the unit: Press power button for 15 seconds
2. Reset to factory settings: Press power button to turn unit into standby, press "connect" and "input" button at the same time for 5 seconds.
3. Firmware Update: Disconnect power cable, connect USB storage, press "connect" while connecting power cable.

Unfortunately, none of it fixed the issue, firmware update seemed to have worked but after the update the same error occured.

According to manual blinking red status LEDs means:

• 2-8 times blinking: As a safety precaution, the unit has turned itself off.
• 4-8 times blinking: As a safety precaution, capability to turn on the unit is disabled. Contact your nearest authorized Yamaha dealer or service center to request repair.

I could verify that +15V and +5V voltage is correct, I guess the others voltages are only available if the device is fully started.

Does anyone had a similar problem and was able to fix it? Are there any other "magic" combinations e.g. to enforce a startup of the device (in order to be able to use the self diagnostic function)? Do the blinking times encode specific error conditions?

Best regards
Randolf

Hi forum members. I was looking for some advice on a recent equipment change.
My existing pre-amplifier failed and I set about replacing it on a tight budget. I bought a Cambridge Audio C500 for a very cheap price even though it was sold as "not tested".
So I set it up into my Arcam P85 power amp and listened to some music. Guess what!, everything worked fine, it was in great condition and it sounded superb.
I was congratulating myself on a bargain but when I shut the Pre-amp down there was a small pop from the speakers and my power amp decided to shut down.
It did this a few times but there was no damage to speakers or power amp.
So my question is, is it safe to carry on using this provided I switch off the power amp before the pre amp?
Also does this fault ring a bell with anyone? I have had a look inside and it is pristine. I cannot see any bad caps etc.
Many thanks for your thoughts.

I made this last year but never used it,I have plan to use this in some A class amp.Plese look on picture.price for all 4 boards 60 euro plus shipping.

This is a I2S to simultaneous mode TDA1541 dac board designed by Miro.

Your own PSU, i2s source and two single op amps (i am not supplying the op amp) or your own IV stage is required to complete this DAC for it to sing.

The 14 decoupling caps for the TDA1541 chip are high quality RIFA MKP, with values as per Miro's recommended BOM. Decoupling caps for the psu are KEMET MKP, and electrolytics are mainly Nichicon FG for the DAC section and ELNA Cerafine for the op amp IV. Resistors used are good low noise, metal films from Nikohm, vishal and Dale. Logic chips are decoupled with high quality Kemet SMD x7r capacitors.

A blank DC protection board is also included in this sale. You will need to get your own components to populate the board if you intend to use this.

This dac is designed by Miro and more info can be found here :
https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-268#post-7159210

Miro also designed the PSU for this dac (not included in this sale):
https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-268#post-7159234
Please study the power supply requirement carefully if you intend to use your own psu design.

Important things to note :
1. If you intend to have no capacitor at the output, it is advisable to have a dc protection board (blank board is included in this sale) as explained in the post:
https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-285#post-7187720
2. i have trimmed the TDA1541 offsets to be null and very stable. Any changes to the board, including inserting different op amp and different TDA1541 chip will require adjustments again. Please do check and do necessary adjustments by following the instructions by Miro. You will need to explore this on your own, with your i2s source connected.
3. All components, including the TDA1541A chip are new, which is only used for the testing of this DAC.

This kit is for sale at US$200 (Shipping with tracking is covered). Paypal FF only please. I am a responsible seller and I pack my item very securely and ship fast.

My dac comes with an external 15V small and cheap wall wart psu. A friend of mine measured it and it produces a lot of noise... not hifi at all as expected.

I'd like to replace it with a more serious linear psu. The Dac has onboard regulators for all voltage lines (12, 5, 3, etc) including the analog section.

What is the best approach:

A) a simple linear psu giving 15vdc that uses just rectifiers and smoothing caps

B) a regulated psu using something like LM317, or LT1086, or even with dual regulators

I'm pretty sure that A) should be better than the cheap wall wart, but not so sure about the apparently better option B) is really problem-free. I remember that once I read somewhere (I can't locate the source unfortunately) that putting in series psu regulated with 3-terminal regs can create more than one problem.

I hope somebody can help!

I decided to add a Pre OUT Power Amp IN loop to my Code 25.

Although I quite like the sounds of the Code 25 I found it extremely glassy and has too much biting high mids for me. So I wanted to add an EQ.

I find the inbuilt EQ pretty poor, and the fact that you have to save each eq setting in each preset, well I found that was a pain in the …

I just wanted a standard -on the fly- tone control I could adjust.



So if you want to do this mod I should firstly say:




DONT DO IT

1. It is dangerous with mains voltage in there.
   
2. You could break the Amp.
   
3. You will have no warranty as soon as you open the back case.
   

So the Amp seems to have fairly standard Preamp out – Power Amp In type arrangement.

The only odd thing, is that there are 2 x signal cables from the Preamp to the Power Amp in.

It is a 4 pin connector on the Pre and on the Power Amp.

It seems like it is a stereo feed from the Pre amp.

I guess that's just for the Aux in from a phone or similar, and it continues this signal on to the Power Amp board where it directs it to the stereo Headhone Jack.

But the Power amp it self is mono of course.

So if you just short the L,R together of the signal wires, then you get mono.

That works fine. You just miss out on stereo in the headphones – but that doesn't bother me.

Note the Code25 effects seem to be just mono.



So in the picture shown, you could cut into that signal wire and make the connections there,

OR I just unplugged both ends of the cable and soldered directly to the 2 boards. - Note, its tricky to do it this way unless you are an experienced solderer.



Wire it up as per the image and when you have no jacks plugged in it will work as normal and you will have stereo Aux in sound on the headphones.

And when you plug in the jacks and wire it through the effects loop then everything will be mono.

Everything worked fine on my modification and the level seems to suit a guitar EQ pedal nicely.


Remember as stated earlier – DONT DO THIS 😉

I am in the early planning stage of a modest cost 3-way. I would like some feedback on modest cost ($40 - $60) 8" woofers. The application would be a fairly compact enclosure of 15 - 20 liters, nominal 8 Ohm, sealed box, using DSP to extend the bass response with a Linkwitz Transform... recognizing of course that the bass boost will have to be fairly moderate given the limited Xmax capabitities of woofers in the price range. The crossover from woofer to mid will be in the range of 300 - 500 Hz.

My two leading contenders are (1) Dayton DA215-8 and (2) SBA SB20PFCR30-8

https://www.parts-express.com/pedocs/specs/295-332-dayton-audio-da215-8-specifications-46942.pdf

https://www.madisoundspeakerstore.c...sb20pfcr30-8-8-paper-cone-woofer-8-ohm-round/

I would be interested in anyone's experience with either of these two drivers.

Any other drivers I should be considering? Since this will be a sealed box design, I would like an Fs of less than 36 Hz and a Qts in the range of 0.34 - 0.45

j.

Project- I have upgraded the crossover in a set of Pinnacle Classic Gold Tower Speakers (approx. 2010 ) with 2-8” 6ohm woofers and a 1” 6ohm metal dome tweeter (Vifa). The crossover I built as a 3-way with 150 Hz -1st order to bass woofer, 3200Hz -2nd order between the mid-base woofer and tweeter. This is completed, installed and will not be changing except for the following 'tweek".

Should I filter out the Looking for opinions on pros / cons of adding a 1st order crossover capacitor of 470uF or 330 uF or 200uf to achieve an approx. cross overs point of 60 / 80 / or 100 Hz respectively to the mid-base woofer.

I appreciate your insights, Thanks,

Have a pair of ESL 9205's coming and now wondering about something to run them.
I have only two power amps one a Naim 160 which I'm not sure if it would run them.
The Second was built by someone I know it coped well with a pair of 57's, about 70w
If the worst comes to the worst I can get something else but haven't a fortune to spend at
present also something that is easily available in UK.

Thanks, Ray

I’m fixing a Yamaha CA-800 that had multiple issues. I’m trying to basically make it as good as it can possibly be. I replaced all of the 2SC458, 2SC1345, Sony 2SA706 and Sony 2SC1124 drivers on the amp driver boards. As well as all of the caps. One channel has bad outputs, they are 2SA663 and 2SC793. Sorry for the crappy image, I can’t seem to find a clean scan of the CA-800 circuit.



Here are the basic specs of the original outputs.




I can go with the same package and put in some new MJ21195G and MJ21196G and be done with the easy swap. They exceed in every way and have a close transition frequency of 4 MHz.

The other option would be using some TO3-P packages and using NJW0281G and NJW0302G, just bend the legs and fit them in and they’d be sitting towards the bottom of the heatsink.



Here are the specs of the TO3-P devices.





Again, they pretty much exceed the originals in every single aspect, but have a higher Ft of 30 MHz. How would the 30 MHz do in this circuit. Curious if they’d be any better, even slightly.

Thoughts?

Jupiter Copper Foil Capacitors.

Rated by Humble Homemade Hifi with a very high score of 13.5

2.2uf @ 100V

There are two available

eBay link is below for safe purchase

https://www.ebay.co.uk/itm/26630218...y44TTrC/ybZnlPmW3YoqjJRExG|tkp:Bk9SR6rTrbvPYg

This amp is in protect .There is no short in the output section .When I power it up the first time it played good audio until I bring up the gain.I already tried the jumper from pin 8 to 14 but no luck

Any suggestions

Hi, felt my last build attempt with these drivers didn't have enough baffle step compensation, upper mids were a bit too prominent. Without resorting to filter, what baffle width or enclosure type wd boost the lower mids and bass? TL?

Hey, everybody...

I'm going active on my tweeters for the first time in 30 years (I know... about time!).

I have a small mid-range woofer that's going to play ~700-4000k hz, and I'm going to mount the tweeter adjacent to it (> 4000 hz).

My plan was to mount it RIGHT beside it--basically touching.

What do you think... would that be TOO close?

I also have the option of pulling the tweeter slightly closer to the listening position than the midrange driver. I've seen this in various A-pillar installs, but I didn't know if it was strategic (e.g., trying to avoid diffraction of tweeter frequencies from the adjacent midrange) or simply a function of the A-pillar angling toward the driver.

What do you think... any value in putting the tweeter slightly closer to the listening position?

Thanks in advance for any advice or info you might have!

These current-mirror IV converter modules are from the 2021 GB that Ripster coordinated. I built two boards for my AD1862 MiroDac, The solid core copper wires are still attached to plug into the opamp sockets on the DAC board (original onboard IV components must be removed before these are installed). The other two boards plus "tester" boards are unpopulated. The matched mosfets for set 2 are still labeled and organized as per Ripster. (Who did a wonderful job!)
Also includes the rest of the SMD components needed for assembling the unpopulated boards.

Sold! shipping included within USA only (payment via PayPal)

Hi all... 🙂

With two Aleph J mono brothers coming to life, I was thinking to share my journey with you here. I have collected so much from DiyAudio and never showed anything. These two are my 10th or something-like-that DIY build of amps, preamps and loudspeakers ... but this time I decided to make the chassis first, because I wanted to avoid another neverending "plywood project".

Few months ago started with CAD design and made decision to make wooden enclosures with heatsinks on the back. Heat sinks are generous and will have a lot of free air outside and inside the box for propper cooling and installation of everything necessary...plus some more eventually, that's why monoblocks...



So, after few weekends in my workshop:



Test of VU meters with Variac:



For now boards are populated only with resistors and cleaned so I don't have problems with cleaning when I solder big caps and trimpots and other small stuff...



First installation on the heatsinks - all holes and screws OK, we can continue with assembly process...



Back side, cooling fins will have enough fresh air for good flow:



Never forget Papa and The First Watt... 🙂

For sale The preamp that started my long journey to audiophilia. A wonderful LDR pre created by a long contributor in this forum. I believe the preamp in its DIY version is described in a thread here. I bought the finished product the member has on his website

https://sites.google.com/view/ldrpre/ldr-pre-mkii?authuser=0

He's selling today the new product in ebay (you can see the link in the page linked above) and you can see the prices there. Selling for 450 euros including the matching apple TV remote control. This is a wonderful audio component and I used it probably for about 1 year before I moved to tube based. I still kept it for a future second system project but my current workload is simply not allowing me to get there. PM me for more information. Can ship in the EU. Outside the EU can be discussed if someone really interested. I know quite a few people in Australia bought the preamp at the time.

I have a pair of Foster tweeters from a pair of Zenith Allegro speakers. Mine are the black plastic housing with the silvery domes and square mounting flange.

Does anyone know the SPL of them?

I used them in one of my early speaker builds and used variable l-pads. I'm wanting to go with fixed l-pads instead so there's less I have to worry about adjusting in my stereo.

hi I've bought a rcx1500 to try and fix from ebay. the issue was described as a CD stuck inside this doesn't seem to be the case however opening the unit I find that it uses the icepower 200asc module .
I've noticed a wire dangling suspiciously does anyone have any idea what this might be ? anything else i need to be aware of when trying to fox this is there anyway of checking the capacitors are discharged with them still attached ? bought as a learning exercise but would be nice to get it up and running again thanks

The existing crossover of my speakers, Braun LS200, has 2nd-order topology. I’d like to convert it to 4th-order on woofer-midrange crossovers.

According to car components of the same brand, there are two versions of active crossovers: 642csi and 642ix. The specs are shown below:

642csi
85Hz low-pass @ 2nd-order Butterworth
170Hz hi-pass @ 2nd-order Butterworth

642ix
100Hz low-pass @ 4th-order Linkwitz-Riley
170Hz hi-pass @ 4th-order Linkwitz-Riley

1) I wonder that in order to apply conversion to my LS200 speakers, can I use the ratio of the 642 crossover series? Let’s say the 85Hz divided by 100Hz obtained a factor of 0.85. If, for example, my LS200’s woofers are crossed at 270Hz @ 2nd-order, applying 0.85 factor to 270Hz would yield about 320Hz. The 320Hz be a cut-off frequency of the 4th-order system, shouldn’t it?

2) The original woofer-midrange crossover of the LS200 speakers are 2nd-order and WITHOUT reversing midrange polarity. After converting to 4th-order, does it require to reverse polarity of one driver, either midrange or woofer? Because the 2nd-order and 4th-order system have phase difference about 180 degrees to each other.

All,

I am trying to see how many here would be interested in a 150W plate amplifier using my Starkrimson 150W modules.

They would be 27cm by 17cm. The price will be around $750 per plate amplifier. It will come fully assembled. And includes the following:
1. Filtered IEC connector
2. 275W AC/DC Power Supply
3. Starktrimson Amp Module
4. XLR Connector
5. all needed hardware and wiring

A mockup of what it would like is below.

I have concern that the MOSFETs to the ACA v1.8 may overhead my pcb due to the fact that I soldered them in a way that the MOSFET bodies and the board are touching each other, or will the heat sink dissipate sufficient heat? Should I have allowed for some airspace?

So the little Musical Fidelity A220 got a bit of an upgrade. A perfect way to destress after work, when I have more time I will do some measurements but for now I'm listening through a little pair of CH50s and at the weekend I'll have the Castle Harlechs (1/4 wave) out and have propper listen.

The alternative motive for this is to practice SMT soldering for another project.



That's small (and that's through the 2x lense light.. not as small as the 0402 or the LT4032s that came for a different project..



I thought the soldering was quite simple (the pins also needed soldering.


Aww..



Doh.. poop. the pin thicknesses on the adaptor kit will not fit the A220 DIP14 socket. So with some 600 grit wet/dry sandpaper.. you guessed it.. the pins fit in the old socket 😀

So after the initial power up on some 8R 100W resistors to check it's all ok, it's on to some speakers for a listen. It didn't go bang.. which is good because I note that Mouser have zero stock since I ordered last week! (I triple checked pin1!).

So it takes the A220 about an hour to reach it's equilibrium with the old MC33079P and the new OPA1644A is no different. Once it's reached it's equilibrium. The key seems to be the output devices / VAS stage like being at a certain temperature.

Initial impressions when cold are snatches of more detail but no musicality. However now the amp has warmed up it seems to show detail in complex pieces whilst retaining musicality without seeming being tiring. Phew. It still needs more listening but so far it seems like a keeper.

The A220 got repaired with new caps, new rectifier, and I thought I may make this change back then so used Panasonic hybrid caps to give a 5mOhm ESR preamp power supply. I don't know at this stage if the preamp power changes really makes a difference but the OPA1644A is a pin-compatible replacement (once mounted on the adaptor) that seems to make a decent step in clarity.

When I have some time I will do some tests to compare the two chips.

I have 2 TKD2cp2508-S 50k pot.
Shield in center,A curve
65usd each 30usd shipping from Japan.
5usd shipping with ferry(taking around 2 month)