Have a transfomer from an old aiwa surround system in perfect condition. Wanted to use it for a project as well as learn from it so I thought I'd ask around. I have attached the schematic for it and just had some questions if anyone could help me learn.

First on the schematic where it showes assembly ground would this be a ground to chassis?

Is it unsafe to leave a rail unused as say if I only needed the postive and ground connection?

Could anyone identify what kind of transfomer this is based on the info provided. From my meauments I get about 43+ , 43- on the VH rails. And then 20+, 20- for the vs rails. Any information or tips would be greatly appreciated.

i have some pcb of this amplifier for 2sk1058-2sj162 mosfets output..
pcb power amplifier Elektor MiniCrescendo 70watt 2SK1058-2SJ162 | eBay

FS: Tang Band W8-1772 8" Neodymium Full Range Driver , P.A.P 15" OB woofers

A pair

Would like to sell 320USD include shipping and paypal fee.
from S.E.Asia\\

used, but still in good condition.

Hello all avid lurker here. Need some help with a amplifer board from an old panasonic surround system. This is purely for learning purposes as I hate to see perfectly working electronics go to waste. Its a amplifer board that relies on TDA8920bj. I wish to try and use it as a basic amplifer. I'm kinda stuck on how to get a signal to pass threw it to speakers. From what I have researched I need to apply 30v+- for power. Then 18v to the fan circuit as this seems to control the signal from what I have seen in the service manual. Also 5v to the mute circuit to get the chip to go into the right mode. I've done all the above but so far all I've gotten is buzzing out the speakers but no music. Any help would be great as this seems to be a great chance to learn from as I've started to jump down the rabbit hole of audio and circuits. I've attached documentation on the circuit but if anything else is needed I have the service manual. The source signal would be either PC or phone. I'm still a newb so I apologize for bad grammar or understanding. Amp was from a panasonic sa-pt650

Hi, I got an old amp going recently and noticed the plates glowing slightly on the two 6l6gc. Here is a schematic could someone familiar with negative bias please let me know which resistor and value change as a starting point to run the tubes Abit cooler. I biased a pp about 25 years ago and did all the math with 1ohm resistors but would just love some simple advice ( my math not so good).

Also saw the schematic is used for different model and lists 7027a as well. Can these go straight in or do I need to check or change the socket wiring? Thank you for any help.

FREE Wayne 4Pi Speaker Cabinets - Wash DC Metro Pickup.


Reach out if you are interested.

I'll probably discard them in the next couple weeks.

these infamous metallurgical UK switching jacks are humbug weathering years of accumulating oxide & severing signal enroute to power amp notoriously used in guitar amplifiers to cut costs to switch by another means (solenoid relay, opto-isolators, mechanical switch).
The guitar amp here is flexwave 65/112 by crate vanished 2018 parts included.

what do i do? emery abrasion the fingerlings? that necessitates removal each fingerling, humbug. they are barbed so u must depress barbs simultaneously yanking them out.

loudtechnologies wants7bucks each plus there's no insulation fibrous washers rear panel anti-earthing isolation gasketing.

why do these fingerlings oxide in the 1st place? is there residual charge left behind for years? or is oxide continuously growing as long as the circuitry is alive with electricity?

I have seen these on EBAY.

Not the usual ON Semi fakes or Motorola.

Anyone have any idea if they are genuine?


FAKES

See later post

With regards to power supply capacitor specifications,

I always read use "low ESR", "high ripple current" but no one ever quantifies that.

What is "low ESR" and what is not "low ESR"?

Is there too low an ESR?

Same with "ripple current".

Can ripple current be too high?

Let's assume (cause this is what I am doing), a PS with a 300VA dual 36v toroidal feeding a 100 watt mono AB amp using four 10,000uf caps at 63v.

This is the PSU circuit diagram,



Octopart lists about 100 different 10,000uf 63v capacitors,

100 different 10000uf 63v capacitors

with an ESR between 12mΩ and 80mΩ and a ripple current between 3.72 amps and 17 amps, priced between $2.20 and $75.00 each.

What would be considered good ESR and ripple current?

What would be bad ESR and ripple current?

Thank you, David.

Just noticed a "blooper" on the tv today...

I caught the tail-end of an episode of Cold Case on TV today.
Episode titled "Sandhogs" from 2006.
Set back in 1947, a tale about a cold case murder.

I suppose it was directed/produced by some millenial-type, or just a slob that didn't do their homework...
Because the closing scene (showing 1947 era flashback) showed a woman punching in a tune on a Wurlitzer jukebox, playing a 45RPM record.

Yet.... 45's were not even OUT yet, let alone jukeboxes designed to play them.
45's didn't hit the stores until 1950, courtesy of RCA Victor Corporation. 😉

Ok, so here is the first of the pair...Using the much maligned RS 40-1284E five inch driver. It's setup as aperiodic as you can see with the one-inch "port" stuffed tightly, as is the inside...it comes out to be 17.08 Liters inside.
I'm trying to do aesthetics as best I can, it does need some touch-ups...one can't be brutal, things scratch & gouge too easily...
Time to hook it up to my Carver TFM-15CB...& take it easy with the gain.

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

Please can anyone offer advice on the electrical parameters that are important for a speaker cable driving the capacitance load of an ESL from a direct drive amp?


Direct drive tube ESL amps can allegedly swing 4kV at 0.3A directly off the plates. Speaker cables could be up to 5m long.



Clearly this is a totally different load to the usual generic speaker amp driving an ESL transformer at the speaker. Obviously safety is paramount but that's about all I know 😱

What capacitance and inductance specifications will ideally match the ESL load? What is needed to look after a tube direct drive amp driving direct off the plates?


Could a coaxial cable work
eg Flexible RG_213_/U
Nom Impedance ~ 50 Ω

Nom. Inductance ~ 0.23 μH/m
Nom Capacitance ~100 pF/m
Nom operating voltage ~ 3 to 5 kVrms
Nom AWG ~13
Nom Power >1kW

Hey.

I'm having problems with MRD M1005.
Amp turns on fine but output section is quiet.
I'm pretty sure the pre amp section works fine because input signal reaches IC301/302. Tho for some reason IC301 seems to have weaker signal, but works. Both IC's put out pwm.
Weird thing is i'm missing VDD on all the output IC's
(IR2010 drivers and IC 303,304,305)
When VSS is -37.7v then VDD is(on the ic's) -35.7v.
I did find that Q306 had failed and was open all the time.
I replaced that but nothing changed.
Been messing with this thing for 2 weekends with no results.
I'm also uploading the schematic for this because it's available online.
If anyone has suggestions or can tell me what im missing i'd be really grateful.

Does anyone have a LL1623 OT model? I attached the cutsheet, I am wired up for 5.6k, config B 60ma single ended.
If someone could tell me how to make one from the data here ( assuming its enough) that would work as well.
Thanks!

Jeff

Hello .

Searching for good quality 33.8688 MHz clock oscillator . Thanks.

I am learning LTSpice and I wanted to model up the amp I built to play with it and learn more about how to use LTSpice.
So I am attaching the schematic I built it from. And the models I could find for the tubes. It uses a D3A in triode mode. I found a D3A triode model but it only references 3 pins in the model file. My schematic is using A,G1,G2,G3,K( or C as it is in the model files). I also found the Pentode model file for the D3A and it is missing G3.
So what should I do? And why is there a triode model anyways? I get that it is being used as a triode but why not include all the pins and connect it as you really would and then there is no need to worry about it being in triode mode.
I don't understand how you can use a model that does not have all the pins you need to connect.
I will have more questions but lets start here.

Hi Everybody
This is my first project & I'am a newbie who started learning to build his own speakers from just a few months ago, 😀
well this is a request for an advice to help me repare a big mistake I did on subwoofers build, this is mostly a PA components based project for use in an average room mostly for loud music listening with minimum distorsion)
My Components are hereinafter (4 towers + 2 subs) :
Amplifier : Kempton 2403 (designed by FBT ) 3 channels PA Amplifier : 2 stereo channels Class A/B : 600 watts per channel @4 ohm (with built in high pass active filter)
1 Subwoofer Mono Channel Line Class H : 1200 watts @ 4 ohm ( I guess low passed at about 280HZ according to my voltage measurements)
under construction : 2 DIY Stereo Towers (50Liters / tuned 55HZ ) : 2 x FaitalPro 10PR300 + 2 HF100 Comp Drivers + 2 STH100 Faital Horns
+ 2 DIY small Stereo Towers ( 34 Liters / Tuned 50 HZ ) :10' 100watts Chinese woofers, I'll replace later+ 2 HF100 Comp Drivers + 2 STH100 Faital Horns

+ under construction : 2 SUBS x Faitalpro 12FH510 ( 60Liters / Bass Reflex / L port / tuned to 45HZ actually - & can be modified for lower tuning

well the big issue is with the faitals 12FH510 the seller told me they'll produce a big amount of bass which is quite true in a certain way, except, the fact that they start to make distorsion very fast,may be exceeding their xmax (7.5mm)
I guess the cabinets aren't suited for them, some friends suggested a horn loaded instead of a bass reflex, & a high pass @50HZ
I've tested them instead in the small towers of 34 liters & the sound gets more even & clear, even to the mid range, so I decided to move them to the small towers & buy decent subs with higher excursion ,
All I can do for now is to stick to the 60 Liters subwoofer cabinets I have & get a 15" that can go as low as possible with decent SPL.
( Daytons not available here/ for Eminence LAB15 : I'll have to wait to April/May,..& the list of unattainable good references is long, & no way to use a car sub, All I can get are B&C 15"
Sorry for the long introduction, my question is which one is better from these two, I'm not looking for fancy SPL I need it to hit as low HZ as possible with safe excursion, & without sacrificing too much on the (50HZ-100HZ Region
I've attached screenshots of some simulations with Win ISD with my 60L cabinets
I used the advisable tuning ( 40HZ for 15TBW100 / 29HZ for 15BG100)
so please ignore the projects Names at top left they mention a wrong tuning HZ
B&C : 15TBW100 (Red Curve)
B&C : 15BG100 (Black Curve)

- Starting with the Transfer function magnitude, I understand this is about linearity, but I can't tell if I have to rely more on this curve for a good judgement about lower frequencies response or on the SPL Curve ? 15BG100 seems to have much more output , but in the MAX SPL curve ( 600watts the amp can handle) things are different : (15TBW100 hits higher down to about 32HZ, then 15BG100 takes the lead.
- Excursion wise 15BG100 runs much safer near to 20HZ.
Note : I did another simulation by tuning the 15TBW100 down to 29HZ (much lower than its FS), & the two curves are superposing (SPL & excursion) with an advantage to the 15TBW100 at the higher bass region.
don't know if this is advisable to do in practice 😕
please anyone having experiences with these drivers can help 😱
these are my first DIY subs & I don't want to mess it up one more time.🙁

I'm tuning my amp with an oscilloscope and I have the volume 37/40 and I can turn the gain all the way up and the bass boost to 3/4 before it clips. Am I doing something wrong???

The background for this preamp - Passive line stages and the TCJ stepped attenuator & NO-Gain/No-Pain Tube Line Stage

This is my 2nd attempt with this design. The 1st attempt ended poorly ! 94v @ 15ma & 12.6v @ 400ma. Voltage multiplier for the b+ & +/- 15v for the servo / filaments. Start up with 45 sec delay plus shut down muting. Khozmo 10k ladder attenuator. 6 layer PCB with 2 ground planes. No dc protection.. currently using this preamp with my 5w JJ 2a3-40 SET.

Dwight

hi
has anyone built this or modified or updated it?

2019 ICAIRN AUDIO Special Offer Home Audio Pre Amplifier Assembly DIY Kits 6J4+6P6P+6Z5P Tube Lamps AC110V/220V Optional|Amplifier| - AliExpress

Thanks

Since high voltage BJTs may be hard to find, I have been thinking about using cascode ladders with low voltage BJTs to use them in high voltage railed amplifiers. Mine is only an idea which I did NOT use in practice. I simulated the idea under LTSpice but found the VAS formed out of ladder cascodes limits the permissible voltage swing which can be obtained by using high voltage BJTs.

I am attaching the simulated schematic using 80V DC rails and entirely low voltage BJTs. Since, this is only a simulation I did not design a power stage, but stopped with the VAS.

The major issue of swing limitation logically seems to have a lot to do with the VAS.

Hi all, I'm hoping someone can help me with a problem.

I have just repaired a Linn Majik -IP Amplifier that had all output transistors blown along with numerous other components in the supply line.

It was that bad I think the previous owner had connected the Pre-amp pins the wrong way around and the thing went bang.

Any way the problem that I have is that I need to set up the new output transistors bias which is normally an easy job following the service manual instructions.

Unfortunately I cannot find any info anywhere on the net and my pleading with Linn and numerous other service centres came to a dead end as no one would provide me with the info.

I have attached a PDF with the Mainboard schematics but this does not mention the process.

Is there any way to set up this amp without the correct procedure?

Thanks in advance
Key

Hi All


I am currently using a DAC by SMSL, called SMSL M3.

It has 3 inputs:
1) USB (using a TI TAS1020B chip as USB->I2S)
2) Optical
3) Coaxial


This AC is connected to a Desktop PC running Windows XP SP3.

Is it possible to get more than 16Bit/48KHz on Windows XP somehow?



If I go to Control Panel -> Sounds and Audio Devices -> Audio Tab,
and click the "Advanced" button,
then under the "Performance" tab, the sliders are all at "Full"/"Best"..





Small note:
When I first got this DAC, I did not have to install anything, I connected it and it worked plug and play..

When I now search google for TAS1020B, I do not even find a Product Page under TI's website..
I was hoping to find one, to maybe find some driver that will enable me to get more than 116/48, but couldn't.

I hope someone here has an idea/experience on how to change this..


Thank you

FS: CLone Note LDR optocoupler volume control (BAL/SE)

Up for sale is a nice optocoupler volume control from Uriah the so called Clone Note, I had a few optocouplers and this design is by far the best! No need for matching and very easy to set up!
The boards are originally made for single ended operation but Uriah send me the adittional small boards for ballance configuration but if you want only single ended no problem I can remove the balance borads easy! Uriah has stoped promoting the volume control so I can provide with more information, manual, working principle.
Here is a review link:
Clone Note Passive LDR Preamplifier Review


I want to include also a nice power supply from PMillet.
Price for the volume control and psu = 220 EUR + shipping cost
Only the volume control (three boards) = 150 EUR
Shipping worldwide.

Hello guys I am looking for a passive line stage so I want to buy some nice TVC or only the transformers...If you want to sell let me know...

Thanks...

Hi

Attached photo is the crossover in a Buchardt s300.

I am in no way experienced with crossovers, but it seems pretty wild since it is only a 2-way (crossover point 2600Hz).

However that may not be enough to keep me from trying something on it. A blind hen can also find corn.

So: is it not fair to assume that the 3 sand cast resistors are connected in series? I can find the same sum of values with 2 resistors in the Jantzen superres series, so that might be a start.

Of course I would need to get it out of my own speaker, and I can then verify on the bottom of the board, it would just be nice to hear any comments beforehand ;-)

I believe they've built in some kind of phase correction, which might explain the complexity. I also know they have a signature edition of their s400 model, where the topology to me looks similar, where they have used superres resistors, superior z caps for the tweeter and cross caps for the woofer. And silver wiring.

Thanks a lot for suggestions/input

I used a s/hand Marantz 63KI for 28 years, great CDP but thought it was time to buy either a dedicated transport and separate DAC or keep it simple, I decided to keep it simple.

I thought about the UK version of the 6006 but decided it didn't allow me to explore digital recording in the future.

Saw the 6007 was available from a Berlin shop with make me an offer, I did and as always shipping from Germany to elsewhere in the EU (I live in France) is the cheapest by far, shipping was only €10.

I disabled the digital circuit and display and set it on repeat for a day. Using my untried Oppo PM2 cans and the long OFC cable that came with it I sat to listen to some CDs that I knew so well.

They are two audio buys that I am so happy I made. Headphones can only relay what the amp and media (CDs) supply. As so many have said that nowadays the quality of CDPs has progressed so much that a lot of negative comments about CDPs are not justified anymore.

I decided that I should first try the h/amp section that Marantz said they had improved even though I have two dedicated h/amps. Marantz didn't lie. So much so that I haven't bothered to use either of them, it is that good.

The Oppos have let the 6007 really shine. The soundstage is deep and so is the bass, forget all about one note bass, this is mutli- layered. Instruments have their own space and though the Oppos are rolled off this isn't apparent on listening to very different types of music. What both the Marantz and the Oppos do is expose so well the difference in mastering of CDs. When the CD has been mastered properly, you will hear it. I am a vinyl head but the quality of the built in headamp has shocked me. Crap CDs have nowhere to hide, luckily I only have a few of them.

Equipped with USB input I'm not set up to try this now but I'll wager it will be to the same quality as the rest of the functions.

It should be possible to tweak the h/phone section and I will make a shielded power cable because I use unshielded i/cs.

If you can visit a dealer who sells Marantz gear and give it a listen through speakers,cans and digital I'd like to hear opinions on the digital section.

A CDP that has a very good h/amp and can play digital sources as well for just over €400 what's not to like.

Hi all, been reading for a while but first post. I'm an audioholic, not phile! I recently got my first valve stereo preamp, however it developed a fault and I'm struggling to find a schematic for a similar preamp. Im no expert so try not to blind me with science but I do have a reasonable understanding of electronics. I think it is a push pull, it has a single 12AU7 running into 2 12AX7s 1 per channel, it also has what I think is a transistor ( 4 legs) that seems to provide some sort of balance, it's connected to pins 4&5 on all tubes.
I'm trying to draw a schematic but I keep getting lost! It has a tube rectifier and a second transformer, but this isn't output, I assume its a 12vac supply.
Another oddity, it has 2 volume controls, an alps 50k inside which I assume is used like a gain preset and an r/c alps 100k.
Any help greatly appreciated, I've got to the point now I'd prob find rebuilding it easier than fault finding hence wanting a schematic. The caps are all wima and it uses flee bay relay switching and remote volume. Cheers Simon

The Klotz & Neutrik 1m Dual Phono Cable is made with Klotz studio balanced microphone cable is ideal for use with very high quality products. It features a PVC jacket, aluminium braided shield and double counter rotating stranded copper cores.highest-end microphone cable transmits signals over long distances with minimum loss and low attenuation, thanks to a range of characteristics including its cross-section of 0.50 mm².



cable no.: MC5000
cond. construction: stranded bare copper, 28 x 0.15 mm
cond. cross section: 0.50 mm2
core arrangement: 2 cores twisted to a pair
shielding: double, counter-rotating, bare copper spiral shield
overall diameter: 7.0 mm
conductor resistance: < 40 Ω/km
capacitance cond./cond.: 55 pF/m
capacitance cond./shield: 95 pF/m
insulation resistance: > 0.1 GΩ x km

Connector: Cinch (Neutrik NF2C-B)
Connection first to ground, then to signal path, when unplugging first signal path, then ground is disconnected
Precisely milled parts
Unique Neutrik collet chuck strain relief
Gold-plated contacts

25.- EUR plus shipping within EU (& GB)

And as always:
Private sale, warranty and exchange excluded.

I had it in mind to experiment with transmission of power through sound waves. The chief motivation for this was the concern about radio waves and their effect on human health.

A little experimentation with a speaker and a multimeter showed that a few milliamps worth of power could be obtained by placing a speaker in front of a speaker playing music.

Predictably, someone has already put this effect into a commercial device, which is cool. 😎 Just found this link:

SonicEnergy | Wireless Energy

Will there be any patent issues implementing this...

From time to time I build a technology demonstrator for a concept I have in my head. This is a pair I was working on to learn active crossovers and finished with what I needed. I designed a passive crossover to work with the internal amplifiers thus creating a powered pair of speakers that will work quite well for someone. If you just want nice speakers, they will work today and work well. If you want an all out killer reference you can tweak the crossover to perfection and blow away $30k monitors. These are great for someone who doesn't know how to use or doesn't have access to expensive toys like vertical machining centers and cnc routers.

The parts are as follows:

Scan Speak Revelator 18W/4531 G00 Woofers
Scan Speak Illuminator D3004/6600 AirCirc Tweeters
Hypex MP250 N-Core Amplifiers 1 per speaker
Hpex HF100 NCore Amplifiers 1 per speaker (not being used in passive configuration)
Various connectors, switches, and custom PCBs for power switching and aux power for optional active crossover.
CNC machined rear aluminum plate
CNC cut wood parts
Rift white oak veneer
General finishes professional line satin poly finish (sprayed)
Extra ports of different lengths so you can tune to your liking.

I will also include a crude active crossover for these, and the design files, both for the PCB and the VituxCAD files.


These are for local pickup only in the Orange County, CA area. No, I won't part them out. No, I won't ship. No, especially not overseas. Yes, that means for you too, even though you asked nicely.

Price is $1000.00 I can entertain a VERY limited demo in my garage to ensure functionality.

Does anyone know if Focal is still making and selling loudspeaker drivers (NOT car audio...) and if so what site or dealer?

Thanks!

WARNING: This thread had a tortuous start during the initial four weeks. Therefore, new readers are invited to start from this recap post, which should save them a lot of frustration. Curious readers can then go back to the earlier posts in order to get a sense of how we got there in the first place... I hope you enjoy the ride!

###

I am currently working on a modular audio interface with the following specs:

- Dedicated ADC board powered by 1 × XMOS XUF232-1024-FB374 (isolated)
- Dedicated DAC board powered by 1 × XMOS XUF232-1024-FB374 (isolated)
- 8 × balanced mono inputs (XLR or mini XLR, TBD)
- 8 × balanced mono outputs (XLR or mini XLR, TBD)
- 8 × AK5578EN 32-bit, 768kHz, 130dB ADC chips in mono mode
- 8 × AK4499EQ 32-bit, 768kHz, 140dB DAC chips in mono mode
- 192 × OPA1612 Op Amps for input channels
- 64 × OPA1612 Op Amps for ouput channels
- TOSLINK S/PDIF + ADAT Input
- TOSLINK S/PDIF + ADAT Output
- 5-pin LEMO Jack Clock Input
- 5-pin LEMO Jack Clock Output
- CC-BY-SA-3.0 Open Source License (Hardware + Software)

I am making good progress, but I have a few questions:

# Op Amp Selection
- Is the OPA1612 the best option?
- Would the OPA2156 CMOS be a better alternative?
- Should I give the mysterious RT6862D/RT6863 of the Khadas Tone Board a shot?

# Input Buffers Design
I am designing the DAC board following AKM's reference design, which is making things pretty straightforward. Unfortunately, the ADC reference design is using the obsolete NJM5534. Where could I find a reference design for an ADC input buffer using the OPA1612 or any pin-compatible Op Amp?

# Connectors
For many applications, the small footprint of the mini XLR connector is really attractive. Unfortunately, it is more expensive, less reliable, and less versatile (male versions cannot be found in certain for factors). Therefore, I am inclined to mount the input and output connectors on separate boards. When doing so, how should I design the connection between these connector panel boards and the ADC and DAC boards?

# Shielding
Should I shield the ADC and DAC chips? If so, which other passive components should be covered by the shields?

Just for kicks, these interfaces will be connected to a Xilinx XCZU15EG-2FFVC900I FPGA with 3,528 DSP slices for low-latency/low-jitter sound processing, using an Enclustra ME-XU7-15EG-2I-D12E System-on-Module mounted on an Enclustra Mercury+ PE1-300 base board. And for the user interface, I will use a Khadas Edge mounted on a Khadas Captain. All this goodness will be released under CC-BY-SA-3.0 as well.

Making a small 2-Way for a mate.

Using a couple of roadkill boxes that just happen to have cut outs that fit a small Jaycar woofer and the little tweeter
Audax TW010E1 10mm Polymer Tweeter Review – AmpsLab

The mid needs a small coil in front as the top end is a bit ragged without it but the little Jaycar CW 2104 woofer is quite a good unit

Any point in trying to use a second order XO on this tweeter?

Both brand new. I connected the ts050 to confirm functionality and the M2X has been out of it's package for examination only.

The plastic screen protector on the ts050 has some fingerprints but it has not been off of the screen.

TS050 Touch Screen | Khadas

M2X Extension | Khadas

$25. plus shipping for both.

hi guys, i'm trying to fix a Behringer Eurorack MX-802, a 4 mono + 2 stereo input mixer. I've been almost a month figuring out whats going on with no luck, i've repaired audio stuff before but never mixers, also i'm new to SMD components , the design does not help much at all, but after all i feel like i can get it working again.

The issue with this mixer is it does a very nasty crackling noise randomly on the #3 and #4 mono inputs, the noise volume varies from very subtle to suddenly very loud. Fortunatelly, some good samaritan on reddit gave me the schematic ,tracking out some minor problems and isolating which stage makes this noise. The circuit uses SMD RC4580 dual opamps for every amplifing stage. Initially one opamp and one diode was blown on line #4, i replaced them and it was working again but later line #3 and #4 started showing this noise and undefined behavior. The first input opamps are the source of this noise.

My main suspects is that there must be an invisible cold solder somewhere, input jack, power supply pins that feed the opamp, an invisible broken trace, a bad
smd capacitor or resistor, altrough i've removed them, measured and all seemed ok, the traces also were ok. I also checked the voltages on the V+ and V- pins, showed 15.6v and -15.6v respectly.

Also it could be an invisible short, but there are no carbon traces or smoke, and this possibility does not make sense because the rest of the mixer works OK, the leds could be flashing because of the shorts, the inputs #1 and #2 work perfectly despite the noise coming out from the other channels. Basically I discard checking the power supply module because the noise would come out from all channels if were because of this(?)

I don't know how sensitive are SMD opamps, maybe i shorted and damaged them without knowing, altrough i've working carefully with them, but i'm pretty sure this does not makes sense at all too because a short on the power lines would affect the entire board

Any help would be really apreciated, and honestly it's driving me crazy, i'll post the schematic and point out which stage the noise is coming out.

also a demo of the noise is on the zip file, maybe you can recognize it.
thanks in advance

Anyone every tried swapping in a 6211 in for the 12AT7 ?

Not trying to accomplish anything in particular here, but I've got some "HP" branded 6211 tubes here (made by GE) and based on some research they are basically a lower mu 12AT7. Apparently used in ENIAC back in the day.

George, or anyone else, is there any risk involved in popping these into the SSE and seeing what they sound like as drivers?

Has anyone here actually built the MJ King Sartori MTM if so what do you think of it and where did you get the dimensions for driver spacing on the front baffle.

I was working on a NAD 3140, general recap as there was lots of leaking. I had everything working, and was using a DBT to power up. I brought the bias up to around 11-12mv (14 is recommended).

I believe the mistake I made was getting ready to set the final bias and offset I plugged it into the regular socket, I let it warm up and after about 15 minutes heard a pop/fizz and one channel went down. I checked the bias quickly and it was very high.

Nothing obvious blew that I can see, and the voltages on the output stage are lower on both channels. Any thoughts on what might have been damaged?

Attaching voltages:

Hi all,

A couple weeks ago I shrank away from the forum believing that my problem was of the careless-error variety. But I'm back to square one after taking lots of care. Here's the deal:

1. I built Steve Bench's tube active x-over and associated supply. X-over point hard-wired to be 2.1 kHz.

2. It does operate properly (as far as I can tell)-- the supply delivers the proper voltages, and the crossover does its job well in two contexts: between a CD player and a television (using the TV's audio inputs), and between a CD player and my pre-amp's AUX input. By "properly" I mean it splits the frequencies (lacking dual amps, I run the highs to one input channel and the lows to the other) and produces nothing ugly.

3. It does NOT operate properly between my pre-amp (Melos 111A) and my amp (Acurus A150). Using the same hook-ups as the other two contexts (highs into one channel, lows into the other), I get the following:

- initial power-on ok
- a hum starts to build in the right speaker
- the hum gradually shifts to the left speaker and becomes VERY loud
- i get scared and shut down the main power to everything
- nothing is damaged, except my pride

I understand that such a "growing" hum is some sort of feedback, but I can't tell what the source might be. I've tried shielding and moving the whole x-over assembly 6 feet from the amp, but to no avail. i've check the grounding, and that seems fine.

My main question: why does my amp seem not to "like" coming after the x-over? Could this an impedance mismatch problem? That's just a stab in the dark; unfortunately, I do not have info on the amp's input impedence.

Thanks in advance for any ideas.

Jay Gordon

Below is phase angle measured on a w8-1772.

Notice the highs phase angle shoots pretty negative......

Tang Band W8-1772 Impressions.
Post 620

I've seen somewhat jagged step resposes also (voxativ)
Voxativ Ampeggio loudspeaker Measurements | Stereophile.com

So, do the highs and lows leave at the same time ?

Hi all.

Simulation file is in the .zip file I have uploaded. Models for the transistors are included in the netlist and you must use LTSpice.

I'm no expert, mostly because I don't have very much experience. However, I still like to contribute things like this every once in a while simply to socialize and also in the hope that others will find it educational. Knowledge is power. Maybe it's some teaching spirit showing through.

Anyways, you may be inclined towards skepticism upon seeing the figures, so to coax your curiosity here is Sander Sassen's ExtremeA, which uses the Allison output to great effect.

http://www.hardwareanalysis.com/content/article/1842.5/extrema-reference-class-a-diy-amplifier/

The distortion figures of this output stage neatly line up with the figures obtained from this ExtremA. So it is likely that the simulator is not spouting nonsense.

Also I believe some (many?) people do not know how to use LTSpice, the simulator I am using, correctly. When used correctly, the simulator can be a powerful friend, but only if used correctly. If someone is interested, I can compile a PDF detailing the proper use of LTSpice. Usually you can get questions answered quickly from the yahoo group anyways though.

Here is the schematic:



All simulations are done at 34V pk-pk output, into an 8-ohm load. 36V rails.

Starting from the right in the schematic, going towards the left:

Circuit 1: Standard Allison

This is the normal Allison output stage. Despite all modifications, this version still has the lowest distortion.

THD @ 100Hz is .000120%
THD @ 20KHz is .000182%

Circuit 2: Allison with my modification, thus: Allison-Keane (not trying to unneedingly claim credit, but we might as well name it something. If it already has gone by some other name then I will happily release my title)

This modification allows one to use smaller emitter resistors, increasing maximum output power if you're using low bias current. It's useful for minimalist amplifiers for squeezing the most out of low supply voltages. Currently, it doesn't make much sense with such high bias current.

THD @ 100Hz is .000351%
THD @ 20KHz is .000528%

Circuit 3: Allison-Keane+Diamond

It may help your understanding of this circuit if you note that the additions have created two Rush Cascodes. As far as I know, I am the first to do it this way.

It cannot be innocently compared to circuit 2, since this version is not cascoded. However, it provides an indicator of the effect of cascoding if we compare it to circuit 4. We find that cascoding reduces distortion.

The main advantage of this circuit is it's rather high input impedance. This lowers distortion by loading the VAS less. This means that the distortion will increase less when the power level increases, and that you can set open-loop gain lower which will make the circuit more stable.

THD @ 100Hz is .000256%
THD @ 20KHz is .000292%

Circuit 4: Cascoded Allison-Keane+Diamond

This version of Circuit 2 serves to point out the effect of cascoding.

THD @ 100Hz is .000169%
THD @ 20KHz is .000222%

Afterword:

This is great and all, but if you actually want to give it justice in a proper amplifier, you will need to hook it up with a really good VAS. Good luck.

I hope this has been helpful and educational to viewers.

Bonzai,
- keantoken

hi all, long time listener first time caller.

I just purchased an O2 amp kit and am looking to add a 1/4" input to it. The idea is to use it as a guitar headphone amp as well. How can I go about this?

I'm relatively new to this: I've built a small amp and a guitar overdrive pedal years ago but have never modded anything. This is just for fun. Thanks for any pointers or links to other threads.

Hi at all !

I am finishing a tube amp, with 6e6p 45 300B tubes.
45 and 300B have filament current DC.
The 45 have 3 Vac , Diode Full Wave , 10.000uf , 10.000uf and 2.5Vcc.

But, when i bypass the cathode resistor , in one of them ( Left side) the plate voltage of 45 tube
scales from 240v to 270v and the -34v goes down to -27v.
In this moment I'm not sure if it goes higher than -34 or goes down to -27v.
It's late night and I'm tired of think.

Change side the resistors 1K.
Swap the bypass capacitors sideways, and always the left side is the one with those changes.

Somebody could help me ?

Hi all

I'm trying to see if I can repair my parents CD Player and need some advice.
It's a Pioneer PD-M602 CD Changer with a 6 disc cartridge.

The reported issue is that it's no longer playing CDs - e.g the tray cartridge mechanism doesn't try to load to the disc - but I noticed a potentially bigger issue, in that the LCD display is flickering.

I'm a novice in electronics, but from what I've experienced the LCD flickering could suggest a power stability issue, which might also mean the loading mechanism isn't getting enough voltage to operate properly?

Could it be a bad capacitor? I have had a look around the power supply board and can't see any tell-tale signs of bulging or bad caps, but it may not have got to that point yet.

I don't have a multimeter or the skills for this - is there anything else I can do to diagnose and fix this, or does it need more professional help?

Hi folks,


I've been wanting to build a mono sub - mostly for music rather than HT - for some time now. Lately I've been leaning towards a TL, since there seem to be some compelling advantages over a simple ported design.



I came across this video describing the math for a "classic" TL design:
Transmission line speaker box math made easy - YouTube


This made sense to me, and I did the calculations based on the Dayton RSS265HO-44 driver:
https://solen.ca/wp-content/uploads/rss265ho44-3.pdf


I came up with a line length of about 103.75", but this is predicated on the area of the line being equal to the Sd of the driver, which isn't really practical since it takes some space to mount it. I understand it's possible to taper the line down to Sd, or should I calculate with a larger a larger line area?



But my main question is around stuffing. My understanding is that stuffing increases the effective line length, but also the effective "closed box equivalent" volume which in turn affects the resonant frequency of the driver in the line. So is it advisable to make the line shorter than the calculations would suggest, to account for stuffing?


But maybe the larger question is, is this still a valid method? I understand there are more modern models, but I'm not sure how to go about using them.


Anyway, apologies for all the "newbie" questions and I appreciate any advice. Thanks in advance.

The original power supply fets were STP11ON8F6

The gate resistors are 47 ohm

Drivers are C3228 and A1275

I have some IRF1018E’s laying around that I don’t use much and wooodnlole to use them up .

Wondering if I can use the 1018E’s in this amp ?

If so do I need to change the gate resistor value or should it be fine ?

Hello,

I have a G.A.S Goliath pre preamplifier i would like to use with a low output mc and a preamp that does not have mc output. What is the power requirements for the Goliath? My Theobe is not working.

Anyone? It s a 6922 tube preamp, i want to improve. It sounds promissing.

Hi,

I've recently seen a design where electrolytic caps were used as coupling caps in some places. Are these ok to replace with film caps? I always thought film caps were supposed top be better for coupling purposes where electrolytic caps are more for power supply filtering where larger values are needed.

Thanks

I've read that it is possible to use (for example) my 8ohm tap for speaker connection and a spare tap (I have both 4ohm and 16ohm available) for CFB. 16ohm would give me more CFB and 4ohm would give me less.

How do I wire this?

Black (0 ohm) and green (8ohm) to proper speaker terminals?

Orange (16 ohm) to CFB terminal ?

But what else gets connected to CFB terminal? Ground? To negative speaker terminal?

Hey People,



I just ordered some PCB's for the open source LM3886. I'm planning to build a 2.1 stereo Set, and want to use three LM3886 for each 2.5-Way Speaker (2x 5 1/2" Mid/Bass + 1x 1" soft Dome Tweeter).

The Speakers will have two Enclosures on the Back, the 1st will be 130mm high, 250mm deep and 164mm wide. There I will put 2 Drawer-Rails of 246mm on the 22mm MDF Ground-Plate and upon these a matching 3mm Aluminium-Plate.

This will be the Enclosure for the 300VA Toroid (2x18V/ 2x 8,33A).
The upper Enclosure will be measured (HxWxD) 400x164x250mm. Same Construction as below, 2 Drawer-Rails on MDF, 3mm Aluminium Plate on Top of the Drawer-Rails.

The three LM3886 will be stacked and mounted on the 5mm Aluminium Backplate which also closes the upper Chamber.
I did this before with LM1875 and I am really satisfied with the result for it was a more or less "0 Budget" Project, and therefore it's Ok.

I'm planning the new Speakers as just a improved Version of the first Attempt, just with slightly more Budget and without all the Mistakes I did at the first Try. The Dimensions of the Box and the Enclosures will be pretty much the same as they were at Mk.I.
Imagine the Box like the one on the Pics, just a little prettier 😉.


Ok, here is my Question: I've got to supply 3 Amps with 1 Toroid. Not really a problem, I did this before with the three LM1875. Anyway, I want to get the best Results, and I am just a Mechanic. I'm learning by doing 😉.



So how would You do this?



I am thinking of one "Main" PSU PCB with 8x MUR860, 2k2/2W Bleeders, 1R/10W, about 60000uF (3x 15000uF + 4x 4700uF) Capacity per Rail, 100nF, 0.47R/1.5nF Snubber. This is the unregulated "Snubberized PSU MkIV SE Rev.3" by Carlos Filipe. So I would put the rectifying Part and most of the Capacity in the lower Enclosure. Now I got ca. +/-28V which I like to lead to the upper Champer and distribute it to the Amps.

At this Point I also want to set my Starground. I thought about some extra uF (Mid/Bass 4x(8x) good Quality 1500UF/50V, Tweeter 4x(8x) 680uF/50V) on small (60x80mm) PCB's to put right behind the Amplifier PCB's.



Is there something I'm not aware of? Would this work? Are there good Quality 1 in 3 out Wire Distributors to buy online? I'm always thinking of a Connection which I'm closing by pushing the "Amp-Sled" on it's Drawer-Rails in. Maybe You know a simple Solution I am not aware of.


If I give each LM3886 such an extra Capacity-PCB, would you put Bleeders and a Snubber RC on it?
What should I use as, not so expensive, Signal Cable? I've got 3 Signals for each Side. I'm thinking about Cat.7 Network-Cable. Could this be worth a try?


Best Regards
Jochen

I am going to build a pre-amp from a triode connected EL84...

What is a good Va and Ia to run it at?

Probably use a CCS or mu-follower configuration with either pentode or SS.

low voltage 100-150v ?

Thanks!!!

maybe 120v 10mA 4v bias..

?

osc tranformer use ee-19 dri gate 20turn

Hello,



from what I can read many SE Tube amps like high efficient speakers. My RH84 should theoretically never drive my 87db monitor speakers. 🙂

They do but but as I am hungry for new project I would like to try something more accurate for those speakers.



What tube or hybrid amp would you recommend for speakers with lower range of efficiency ? Are push-pull amps a way to go ? Or it is hybrid/ class D task?


Thank you for suggestions

I have some basic questions and apologies if this has been covered.

My goal is to use a raspberry Pi4 as a multichannel DSP / room EQ by using the optical out of a TV (I believe my LG TV outputs 5.1 over optical), by adding an optical input to the PI4 and using CamillaDSP to handle the processing :

This guy makes an optical input - tinyToslink - Raspberry Pi Optical Audio from Beni_Skate on Tindie.

Then by using software on the PI4 to do multichannel DSP, outputting that signal via USB to a OKTO dac8 PRO - Okto Research

My hope is to bypass the need for an expensive, bulky AVR with possible sub-optimal amplification and allow use of a high quality multichannel DAC and power amps

Would CamillaDSP be able to do multichannel DSP processing on a PI4 by utilising the TINYTOS LINK?

Is my goal even possible? Are there hardware limitations within the PI which would make this unachievable? Would anyone else like to have a PI do multichannel DSP?

Design flaw or defect somewhere?

Read all about my woes here,
https://www.diyaudio.com/forums/pass-labs/290776-50w-single-baf2015-schade-enabled-142.html#post6445341

Regards,
Dan 😕

Good morning everyone, today trying to repair this t2500.1bd, it had already been tried to repair, or obviously they did not succeed, the first problem I see is a consumption of 5 amps without load and with the diodes (4) removed from the card main, the mosfets of the source that go in the first transformer are those that heat up (6 mosfets) the only difference that I see with the source of the center is a slight increase in the gate voltage, let's see what you think

I recently finished a 3-way design with some "old" stock drivers from my stash. One of the tweeters has a slight crease in the metal dome, although it functions just fine. This tweeter is Audax TM020J5 - 20mm (3/4 in), 4-ohm, Titanium dome.

I am looking for one TM020J5 to replace the blemished one. I would also be willing to get a pair.

Hoping someone here might have 1 (or 2) in their stash.

PM if you have any available.

Don't know if it is the right place but it's just a question
How much do you guys think a pair of this amp are worth (UK market) and not asking for *bay prices.
Regards

Dear all,


I 'm looking to buy an US imported B&K ST2140 and a pre-amp REF 5 S2 here in France where power is 220V. Both manual mention a possible switchable voltage back and force from US 110V to EU 220V. Anyone knows how it works exactly? There seems to have no buttons for that on both chassis.


Thanks.

Hi my friends,

I need your guidance once again.

Do you know if I can connect this ADC:
Lusya decodificador de Audio Digital I2S ADC, sin perdidas, compatible con salida de senal de 24 bits 96K I2S T0521|Conversor de digital a analogico| - AliExpress

to this DSP board:
Lusya ADAU1452_DSP tablero de desarrollo de aprendizaje moudle tablero DSP con codec F9 006|Accesorios y piezas de reemplazo| - AliExpress

I know I can conenct it to my 3e Audio ADAU1701 as stated in this thread:
https://www.diyaudio.com/forums/dig...utpus-3e-audio-adau1701-dsp-aliexpress-2.html

But now I find in need of having, at least, 6 inputs to my DSP.

Another alternative would be just to buy another ADAU1452 and use a double gang 10K potentiometer for volume control on both DAC's at the same time, getting 8 input and 16 output.

Please your comments!

I need others' experience here.
I have a 2018 Ford Edge and the original, single element horn said:
'Excuse me, I hate to bother you...'
I updated it to the dual element and it's fine but it says:
'I hope you realize you shouldn't be doing that.'
Where I live, a horn needs a sense of authority and I'm getting too old to play that role. ie: I don't get out of the vehicle to encourage my point of view anymore.
I want one of those funky spiral train horn things that not only fits under the hood, it also gets their attention long before they need to know 4000 lbs. of vehicle can really hurt when not careful.
The internet is full of these horns but I am uninformed. Help me out if you can. Sample audio clips seem to be scarce.
BTW: The best answer receives a 'get-out-of-diy-jail-free' card personally signed by me, if you happen to have future indiscretions. 😉

Hi there

I am trying to achieve a wide range (>100) tracking between two CCS's having a 1:100 ratio.
I need them for a beefed up version of this beta tester:
https://www.diyaudio.com/forums/equipment-and-tools/349199-constant-ic-tester-master.html
I want to build a 5mA to 5A version, but with the capability of reaching 50µA on the 5mA range.

For regular ranges, tracking in a 1 to 10 ratio is OK, but for the first range, a 1 to 100 ratio with an acceptable accuracy is required.

Because of the configuration (NPN/PNP), I want to keep things simple (no opamps).

This shows the basic option:



At low currents, there is a quirk;

Another approach:



This one is a direct application of the basic theory, but it has other issues:



Etc, etc (I tried many other options)
Any ideas? (taking into account all the constraints, obviously)

Hi,

Does anyone here own a laser engraving machine?

This would be a reluctant purchase. However, we've been using commercial firms for years, and there seems to be a pattern emerging: things work fine for a few months, and then they make a mistake, damaging a bunch of front panels, whereupon they refuse to pay for the damage. I expect that 5-10% of panels might have a flaw, but firms seem to send runs and expect us to pay for trashing them. In light of the frustration, I'm wondering if we need to get a machine and do it ourselves - that way we'll only have ourselves to blame.

The panels we engrave range from 19" alloy, to 12" square powder-coated stainless. I guess we probably wouldn't ever need to do more than about 20 in a month.

I've seen flat-bed units on Ebay. Prices seem to vary like mad.

How long did it take you to master your one? If you want one that's robust and won't cause stress in terms of maintenance, what sort of budget do you think we'd need to allocate for the above kind of work?

Thank you in advance!

edit - for the sort of work we need to do, what sort of maintenance budget do you think the thing will need to have allocated to it? (assuming we make a wise purchase, and not something on its last legs). How long do the tubes last?

I'll start of by saying I guess the answer is no but I figure won't hurt asking given my limited knowledge...
Recently picked up a pair of speakers with known tweeters not working. Confirmed the crossover works fine (tested with a known working tweeter) tested both tweeters with a multimeter both no reading, pulled diaphragm off and found both had a break in the same spot. See attached pic.
I'm guessing the chance of fixing this is not going to happen? (Can an expert fix these as I definitely don't have the tools for it)
Speakers are wharfedale 512.2 '88-90 vintage.

Thanks for your thoughts,
Everhard.

4 SMSPS from MicroAudio 600W @ +/-67Vdc . These are made with premium components.

Great for class D

One matched pair-take off- (like new): USD70 for the PAIR
One matched pair -brand new unused-: USD 90 for the PAIR

2 amp modules already mounted on a aluminum plate for easier install.
Like new barely played. The entire amp was de-assembled.

One on the resistor was changed (faulty); tests on bench are fine (see picture)

New, the pair was going for over 700 Euro with shipping and takes

Looking at USD350 for the PAIR + shipping + 3% Paypal

Also available Mirand Audio DC sensors USD60 for a pair.

Regards all.

I own a near 30 years old Well Tempered turntable, original model with square motor base. These turntables use Hurst motors equivalent to the current Hurst PB-3230-001, a high 38.8 mN-m torque, 600 rpm, 2 phase, 115v 60Hz, 10 watts A/C synchronous motor, which are most similar to the one used by VPI in their SAMA.

Sometime ago I noticed that the table was running slow and embarqued in a process to get the table running at the correct and stable speed.

To that end I acquired scobham’s Zeus motor controller and built a 25 watts 2 channel D Class amplifier. Similar to Pyramid’s controller and amplifiers project but with feedback loop. Great kit super well recommended, and Stephen's support has been great.

Anyways, I have been able to get the motor running quite better than originally, but as Pyramid has noted on several strings and postings, apparently the 10 watts Hurst motor does not lend itself to very precise, constant speed operation, and no matter how much control and adjustment is made to voltages, frequencies and PID parameters, the motor’s speed still oscillates more than say Premotec / Airpax/ Phillips/ Allied Motion motor used on may turntables.

I am considering changing the motor for another model, but the Allied Motion 990411131813 motor used on may turntables has a much lower torque capacity (I believe of 20 mN-m) than the Hurst and I believe insufficient to consistently start the platter.

I have also read of Pyramid’s implementation of the 3 phase dc motor and control, and I am considering it, but wish to know if there are other 2 phase A/C synchronous motors I can consider.

So…. Beside the Premotec / Airpax/ Phillips/ Allied Motion motor and the Hurst motors, which other motors are used on turntables or recommended to use substituting my current 10 watts Hurst?

Thanks.

For JBL 4670D pro cinema speakers.



Or a couple of really clear pictures of the actual networks, showing part values and connections?


Thanks!

I have searched the I-way, and in many different ways the typical question; best recorded album/cd, Audiophile quality top 100 etc. ad nauseum...
At one point you see a pattern emerge, but the lesser known stand outs are never mentioned...

Except for the very last one I posted below, I was 100% surprised how freaking amazing it sounded on a reasonably good setup... The last one I knew would be amazing, but never see anyone mention it...

I thought it might be fun to start a thread where everyone mentions at least 3 surprise audiophile - superb sounding albums or songs that never get the credit they deserve !

Im starting this with...

Tears for Fears - The seeds of love
Natalie Merchant - Ophelia
Nigel Stanford - Solar Echoes

Hi.

I'm working on a pair of Mordaunt Short Loudspeakers and need to understand the electronics involved.

In terms of crossover restoration one option it to replace like for like.

If someone has transposed the Speaker wire terminations this could be affecting the sound?

My question is:

Are Loudspeaker Driver terminals universal in terms of the current flow or are they +ve and -ve and need to be terminated correctly?

The Tweeter (marked Made in W Germany 058 8 Ohm 95-6464) has terminals marked + and -

The Woofers (MSB C No 029960) don't have any markings identifying the polarity of terminals.

Are the Woofer terminals non polarity conscious and therefore universal in terms of their orientation with the speaker terminals?

thanks

Cliff

Bjts have Beta droop at low current.
How bad, is this ?
What low power transistors have good Hfe at collector currents well below 1mA ?

I'm thinking of building the LXmini speakers by Linkwitz (RIP), for those who don't know about those speakers check here: LXmini Challenge


I'm honestly interested because i heard they're somewhat tolerant to imperfect room placement and because of their small size.



Did anyone here build them? How was the experience?


Pros and Cons?

Hi ! i am attaching a power supply that i really would like to understand the working principle (schematic attached)
The input is a single 12VAC ... the output a dual +/-30VDC
How this voltage step-up is possible ? i really do not understand
Are the transistors increasing the voltage ?
Does this kind of psu have a name ?
I really like the fact that starting from a single VAC can provide a dual power supply
Can it have the same performance of a more conventional dual supply using a center tapped transformer ?
Thanks a lot for any help
gino

Anyone who known where to source these? I am in need of 50-100 pieces. PM me

I have been borrowing my brothers Wella solder station that is about £250+ (T0053250399N | Weller WS 81 Soldering Station 80W, 230V | RS Components) to replace and I like it, have got used to it but would rather not spend that as he now wants it back!! It is the model with a digital display, not made any more.

It is 80W, would a 60W be sufficient for working on a valve amp and making interconnects etc?

thanks,

Covid keeps me from traveling so have a lot more time and what better to do but go back to old hobbies 🙂

So I've got some old amp boards (destroying a few but I had many) LC Audio millenium and now building a dual differential or bridged balanced singled ended dual mono 2x300w amp using 2 Hypex SMPS 400A100 PS and other potentially interesting stuff which I will get to later if it works out.

I've placed the two amp boards inverted to each other which when looking at it makes it very convenient to place additional filter caps directly on the +- rails between the boards not involving ground.

The Hypex PS keeps the rails in check relative to ground meaning they wont wander and am I correct that adding caps for additional filtering between the rails (and not to ground) is all that I need to potentially improve power supply noise rejection?

I am a bit new to bridged amps and a pure balanced signal path and having had some serious ground OCD in the past I sort of struggle with the idea of not getting ground involved hence the ask for confirmation?