Way back around 1972 I picked up a copy of The Audio Armature. Back then they referred to an an amplifier project from a few years earlier called the Wilson Twin 20 at least I think that was the name. Does anyone here have the schematic of that amp ?

During a discussion about an add-on for upgrading 317/337 regulators, a question has surfaced:

Would it possible to design a "superreg" using only 12 components or less, preferably all discretes?

Here is an answer (to be taken with of pinch of salt, and in the spirit of Christmas magic, something that participants to the previous thread seem to have missed).

This example uses 11 discretes, and outperforms a cap-fitted 317 on all key parameters (without using any cap).
Does it qualify as a superreg?

Certainly not by today's standards, and the DC stability is approximate because of a crude, first-order temperature compensation, but the central question was noise-related, and it does not perform too poorly in this regard (and there is a lot of room for improvements, since the circuit is based on the <12 components constraint, and no cap).

May I remind everyone that this site is named DIYaudio, and members like to fiddle with creative, cheerful and unorthodox solutions (which is not synonymous with worthless), which is why I post this circuit.
Grinches, etc., please don't look further and move along....

Here is the PSRR of the basic circuit: ~80dB




This is the output impedance: ~1.6mΩ



The measured noise, in a 10Hz to 10kHz bandwidth varies between ~2µV and 4µV, depending on the LED used and the error amplifier transistor.
The most favorable combination (I only made a limited number of tests) is an old Siemens green LED (CQ-something) and a BC337-40 resulting in ~2µV, and if the LED and transistor are from 6N139 coupler (an attractive solution because of the thermal tracking, the single component and the good temperature compensation), this becomes ~2.5µV.

It is possible to compensate some of the parasitic parameters like Early effect to the first order by adding some tweaks.
The practical range of this type of tweak cannot exceed one order of magnitude, ~20dB: beyond, the adjustment become too sensitive to be of practical use, but for DIY applications, 20dB is realistic.
Here is the result with tweaks active (becomes >12 components, of course)/





Note that R3 is not a physical component: it simply materializes the order of the components on the output track: R5 needs to be upstream of D1.


It is important to note that the circuit is not self-starting: this can be seen as an advantage or a drawback, depending on the application.
In a previous example, I have used this as a "feature".

Disclaimer:
The circuit in its present condition is suboptimal in many respects: its main purpose is to deliver nice figures within the 11 discretes constraint, and although it works (I had to make actual measurements on the breadboarded version), I certainly do not recommend using it in its raw state.

It could become really useful with only cheap and minor amendments/additions, but it will probably remain unable to beat the best silicon $£€ can buy, made by the top foundries.

I will discuss later the practical adjustments required if the circuit has to be used in the real world, by people that do not necessarily have access to Farnell, Mouser, etc. and for whom a 317 is already a kind of luxury (2/3rd of the world population?)

Folks:

I am planning on building a dual mono F6 amplifier using two 200VA toroids. In order to save space in the chassis, I'd like to mount the toroids on either side of the long end of an "L" shaped aluminum bracket using a single bolt. Can anyone confirm for me that this won't cause a problem?

Thank you,
Scott

For Sale

Two used Aurasound NS15-992-4A 15" Subwoofers

Bought second hand but never used them. Tested recently and they work.
There are some scratches on the bottom and the gasket has some damage where it was stuck to the previous owner's enclosure.

Not sure how much people are willing to pay but I know they are quite rare and difficult to get hold of.

I'm in Surrey in the UK. Happy for people to collect or I can post. They are 22kg each so looking at £20 postage in the UK and would be very expensive to post out of the UK.

Offers please.

The subject OPT is employed in a line preamp with sum total one tube, a 5842 RF type. MQ is retired. I respectfully request a list of the best replacement transformers to build a matching preamp. I also need to know the cost for the replacement trafo.

Upon request I'll post the schematic which I sketched. The MQ DS 050/600 OPT has 3 output leads with 3 different gain options of about 8, 18 and 21 dB. A fixed gain of about 14-17 is OK for my application.

A couple days ago I asked MQ for the trafo specs and no reply yet.

I just read an interesting article about power supply design and would like to draw your attention to figure 6B and 6C.

Design Considerations - 2

The author describe the "spectrum of harmonics" from capacitor input and choke input filter is different, and that would affect the sound. I guess it is saying that the ripple does not only sound like 100/120hz hum but all different kinds of buzz/harsh at higher frequencies. I don't notice much elaboration on such view from the internet and the main focus on PSU design has usually been how much p-p ripple remains after filtering. Nevertheless I did noted a reply in a post in this forum that choke input sound "ease". That comment seems coherent to what the author suggests.

https://www.diyaudio.com/forums/tubes-valves/101064-motorboating-post1199057.html

What is your view or experience on choke-input filter on output stage / preamp / stage?

Is there any real world difference between 2SC5242 and 2SC3281 in amplifier repair?
Also, can TTC0001 and TTA0001 be used in place of output transistors in an device that originally used 2SC3182 and 2SA1265? (I dont want to use PMC manufactured devices , and only asking because I can source TTC/TTA right away)

Hi everyone, has anyone here done the HA1452W opamp swap with another device? I have a JVC A3 amp that has a dodgy phono stage and since every part checks out, only the op-amp is left, both channels have a hashy background but the right channel is much worse. All voltages are perfect, as are the caps, I pulled several and checked capacitance, replacing a couple that had corrosion on their legs. The Line stage is spot on.
I have three possible 14 pin options here, though since I now will have guests any moment, I haven't been able to check their circuit details. They are: AD713AN; TL074CN and an LM324N.
Would really prefer a drop in replacement if possible, but it's no biggie to alter any compensation caps.
Be grateful if anyone can help out here.

Authorities warn of TikTok 'outlet challenge' causing fires - CNN

I can't believe that the level of stupidity between young people could go so far.

Hello,
I've been enjoying my TSSE for a while (since 2009) and tonight I smell something is burning after using my amp for an hour.

When I detached the board from the case C3 was blown as well as the fuse.

What may be the cause of this? I can see from the schematic that C3 is part of the power supply. I believe upon visual inspection that no other part was involved.

Thanks for your time.

2 monochannels with LM3875TF. Also 2 rectifier boards and and a PSU board with Kendeil 22000 uF 40V caps.

Make me an offer. Shipping only within Europe.

Hi! I have a punch 851s, it comes with the lm317 shortcircuit. Replace it and again in short. Find d3 in short and replace it, im testing with a lm7815 for the moment.

I pull out all output mosfets, all are ok. Rail caps out of the board for test.

I have +- 47 volts on rail. -20v on 640 gates and +20 v on 9640 gates, so if i put one and one the ps shuts off, both are on at the same time.

The first problem with the lm317 in short was +47 volts instead of +20 volts on the control circuit. 4 47ohm resistors replaced because the high voltage. All 1am and 2a and 1q smd transistor are ok. Bias pots 2k ohm readings are ok. A56 and a06 ok.

I have the 800a2 schematic, are the same board.

Any ideas?

Does anyone know what this transistor labeled d4 is?

Heard some of the Joyo amps running one tube and PWM output, sounds pretty good. I was wondering what the circuit was like and nobody bothered to dissect one yet. So I was just wondering what you would do given few constraints.

Hello group,
I have an ADS power plate 120 with turn on problems. When turned on the power supply just has like a one second pulse, like burst or spike and the goes to zero volts, voltage does not go to high either. Not sure if the amplifier is in protection or power supply itself is bad. looks like it is a self oscillating power supply. any help greatly appreciated.

I just finished a series regulator for amps that require a stiff negative supply. I have a couple friends building GM70 amplifiers and i thought this would be a welcome addition.



Ideally you would connect rectified and smoothed 230VAC to the inputs.



The schematic is based on the supply from the Tek567 tube O'scope


Pass tube is a 6080/6AS7 or pin equivalent.



The long tailed pair ECC88 runs into a PNP transistor VAS. This gives a large amount of amplification.


Any thoughts?


Once im happy about the boards i will post the gerbers for free in my gerbers thread.

With my very basic knowledge of speaker design, enough to fill a thimble I'm hoping to increase my terminology at least enough to describe speakers eloquently... After that some questions to expand my understanding of characteristics...

If you have a speaker that's detailed, crisp and accurate, could the opposite of that be considered buttery, smooth ?

If that's reasonably close, Im going to go out on a limb and pose a hypothesis that is looking for affirmation...

A speaker that is crisp, accurate and detailed has a better chance of being altered to sound more smooth or buttery.
Conversely, a speaker that is already smooth and buttery may take much more work to become crisp.

In my mind (What a troubled place it is!) I imagine a crisp sounding speaker as one that can accurately reproduce any instrument thrown its way. That its cone has the ability to move when and where it needs to, reactive and with purpose. Now, I imagine the smoother speaker as one that more or less averages the signals sent to it at some level so that it might not hit every frequency tossed its way, but can reproduce a reasonably close average of them....

Transformation from one to another, from crisp to smooth is what interests me... How does an experienced speaker builder remove some of the resolution and design in a little more mellow ?

Hi all,

I want to do a recap on my NAD 1240 preamp and making a parts list and I am wondering if someone out there who is more experienced with capacitors can tell me what the capacitance of these two yellow (both the same) capacitors are in the center of picture. Near as I can guess it is 77 or 11 uf and 50 volts. The 50volts is pretty obvious but the 77 or 11 isn't so what do you guys think?

Thanks to all in advance who reply.

Hi,

My project requires 3 4,700uf capacitors. I purchased 3 of the pictured Kemet caps from Mouser without realising that they had multiple connection points.

I am uncertain as to what I have here. The pins are labelled 1-4 and a single “-“ negative.

Do I have a single 4,700uf cap or 4 4,700uf caps? If it is a single cap, what is the best way to make the connection to the circuit?

Thanks in advance for help.

Lou

Trying to design a series notch filter using online calculators for a Dynavox LY401F. I'm getting really high capacitor values. Am I reading it wrong or are those values correct.

Mahalo,
Series Notch Filter

Re = 4.3 Ohms

fs = 53 Hz

Qes = 0.29

Qms = 3.34


Parts List
Capacitor
C = 2408.8 uF
Inductor
L = 3.75 mH
Resistor
Rc = 4.6733532934

I could use some suggestions I have 4 of these boards that have a static sound present on the 40hrz output when a sub is hooked up the the board. The amp works but just sounds off, like static is present.
What component(s) would cause this. Opamps or inductor? Some suggestions would be helpful as I have changed a few componts already and it made little difference.

Can anyone tell me what size fuse to use for my F5 turbo monoblocks with 41V rails? I have 88000uf per rail in the power supply, to the extent that matters.

I was thinking 4amp slo blow?

Hello kind people!

i've been working on improving my room as much as possible for an accurate but enjoyable stereophonic experience.

My room is L shaped. two rooms basically, the total length is 5.6 meters, width of the first room is 3.3 meters, and the second room is 2.4 meters. height is 3.3 meters for both. made with concrete.

It's used for music primary and a home theater aswell.(the walls are covered in very thin black fabric to hide the rockwool panels and help with the projector's picture)

i'm using infinity kappa 8A speakers, tweeters are 70 cms away from the side walls for both speakers, and the back tweeters(they're dipoles) 60 cms away from the back wall.
sitting in an equilateral triangle with the speakers ,185 cms distance between the tweeters and each speaker and my head.
tweeters are toed firing and my ears(to interefere around 10 cms behind my head)

worked on the RFZ room approach, using 5 cm rockwool panels to absorb my first reflections, and to have a long ITDG. i treated my side walls, floor, ceiling and front wall(wall facing me), back wall is 3.3 meters away from me and according to my calculations it didn't need absorbtion(comfirmed by the ETC graphs)

i installed 10 cm thick rockwool panels on all the corners of the room, with 8 cms of air gap behind the rockwool.
i encountered big nulls in the 100-250 hz area, so i built 3 Front loaded horns 2 of them using 12 inch woofers flat to 16 hz and the 3rd using a 21 inch B&C woofer(designed as bed with output behind the head's listener for very near nearfield listening for movies) flat down to 12 hz in room.
and crossed the subs at 150 hz with the main speakers to get rid of most of the nulls.

using a minidsp 2x4HD i time alligned the speakers and subs, and PEQ'd them aiming for a Harman curve(the listener's curve mentioned in Dr floyd's sound reproduction book)
used FIR filters to correct the phase and improve my impulse response and ETC significantly.

i'll attach pictures of everything and would appreciate comments and helpful tips.

Fluid was pretty helpful on the Rephase thread, he and wasayso made some observations about the room's RT60 of 200ms being too dead(removing my panels didn't increase rt60), and that i can use reflections to improve the experience, like the possiblity of adding Haas kickers or ambience speakers.
I'm a bit confused about this topic, keeps reading different professional opinions this.

any helpful tips about anything i can do to improve the experience is much appreciated !

I'm repairing an Audiobahn a2800e, and someone has robbed the cooling fan and rca jack out of it, as well as a bunch of misc screws. If a picture is needed, I'll take one when my replacement rectifiers come in and I get back to working on it.

Does anyone have any Audiobahn parts amps they could sell?

Latest inexpensive USB DACs with ESS chips have excellent params, up to 768/24. Getting better with every new DAC version. E.g. Khadas Toneboard for 99USD.

Parallel-output ADC with external clock - e.g. 24bit EVAL-AD7760 for 65USD EVAL-AD7760EDZ Analog Devices | Analog Devices EVAL-AD7760EDZ ADC Evaluation Board for AD7760 | 698-1407 | RS Components

The Khadas board has two crystals for each audio rates family(24.576MHz, 22.5792MHz), switched by the USB host, the selected clock signal is available at its external socket.

The AD7760 board has an SMB jack for external clock (buffered with NC7S08). Depending on its configured filter setup it could sample at 3.072MHz (24.576/2/4). That would allow running DAC at 768kHz and ADC at 4x that synchronously, being able to sample higher harmonics of a DUT fed with the DAC signal. Synchronous DAC/ADC clock is important as it allows precise FFT of the measurement signal.

A simple short-traced pinheader adapter board would connect the ADC board's pin header to RPi4 GPIOs header, digital levels should be compatible (2.5V ADC, 3.3V RPi). Optionally level shifting 3.3V DAC MCLK -> 5V ADC MCLK for optimal operation (as mentioned in the AD7760 datasheet, not required for the start).

Both boards have complete documentation available (schematics, PCB layout).

Measurement signal generator on linux host -> USB async at 768kHz/24bit -> Khadas board -> DUT -> AD7760 board -> 16bit parallel + control on RPi4 GPIOs read by kernel thread running on isolated CPU core -> USB UAC2 async gadget at 1536/24 or 3072/16 (for now, possible to support 3072/24 later) -> different USB port of the same linux USB host -> any software analyzer (fft - jaaa, scope).

Switching DAC/ADC samplerates would be synchronized, any combination supported by the HW would be available.

A different ADC could be used, requiring just a different communication channel in the special kernel thread on RPi (e.g. SPI, but the parallel bus has the highest throughput).

I cannot develop the analog circuits, but I am willing to take the RPi4 part. I am working on the async UAC2 gadget anyway. IMO it could be an interesting and potentially useful low-cost project.

Hi all,

I bought some Laptech crystals in one of the first TWTMC group buys, however, would like to exchange some of them for different frequencies / SC-cuts in relation to the upcoming GB. Therefore I am selling these crystals:

AT cut:

6.144 MHz (has been soldered but only used briefly; EUR 25 + shipping)

SC cut:

98.304 MHz (new; 45 EUR + shipping)

Cheers,

Jesper

Hi,If someone out there from Germany or other Country have maybe this Hobby Hifi speaker building magazine to sell?I will build the Statement speakers from this magazine.Or if someone can me make some scan,I will pay for this.By Hobby Hifi in Germany they have no option for online download and to get some copy of this magazine is so complicated,its crazy.Plese if someone can help me about this,to get the scan of Statement speaker project.

Hi guys, I have an "Alto X34SW" stereo 3way active crossover that mounts tl074cn. I'm not so convinced by "the voice".
I know there aren't many, good, quad opamps on the market.
according to you replacing tl074 ... with AD713jn? you have other tips.

Hello,

that's a project of mine. I have used them for an old project with tubes.
Two power supplies available.

Each Pcb has on it two maida's HV regulators wired for output bipolar operations. AC in, +/- DC OUT.

Has a set resistor to set the "center" output voltage, and a trimmer to refine it (+/-10% around it).

MAX AC-IN 500v
MAX DC-OUT 500v
max output current (per rail) 800mA
15V dropout

the maida iteration used for that powersupply is inspired from the awesome work of Tomchr, he called the 21st century maida.
Take a peek HERE and HERE

[the pcb is easily hackable to split the two rails and get two positive (or negative) rail, instead of the bipolar configuration.]

Boards are cleaned in a ultrasonic bath after soldering in order to remove any nasty residue.
All the components from Mouser.

Price for one is 80€ fully assembled.
140€ for both of them

Shipped everywhere.
Paypal payment.

En:

Hello forum friends! all right?

This is my fist topic here on the forum so I ask you to have a little patience with me. I wanted your help with this amplifier that I won. Researching a little about discovering that it is an amplifier a little difficult to find, but it does not mean that it is of quality.. I liked the sound it produces, it's very sharp, shiny and very strong on the bass.. (I used a pair of 95 db sensitivity speakers each, and that helps a lot.) I did a type of reverse engineering to try to understand his circuit, but in the simulator it does not work right way. I would like the opinion of you friends. What you think of the circuit? Whats wrong? Is it possible to improve?

Attached is a PCB image of the circuit in PDF and * .ms14 (Multisim 14)

** About the amplifier and the creator of this circuit:
This circuit is by a Brazilian engineer known as "Sossego" (in English it would be quiet), in which few units of the same amplifier were produced. I believe that this amplifier, the P800 has a maximum power of 100w at 8 ohms or 130w at 4 ohms.

PT:

Olá amigos do fórum! Tudo certo?

Este é o meu primeiro tópico aqui no fórum, então peço que você tenha um pouco de paciência comigo. Queria sua ajuda com este amplificador que ganhei. Pesquisando um pouco sobre descobrir que é um amplificador um pouco difícil de encontrar, mas isso não significa que seja de qualidade .. Gostei do som que produz, é muito nítido, brilhante e muito forte no baixo .. (I usei um par de alto-falantes de sensibilidade de 95 db cada, e isso ajuda bastante.) Fiz um tipo de engenharia reversa para tentar entender o circuito dele, mas no simulador não funciona da maneira certa. Eu gostaria da opinião de vocês amigos. O que você acha do circuito? O que está errado? É possível melhorar?

Em anexo está uma imagem PCB do circuito em PDF e * .ms14 (Multisim 14)

** Sobre o amplificador e o criador deste circuito:
Este circuito é de um engenheiro brasileiro conhecido como "Sossego" (em inglês, seria silencioso), no qual foram produzidas poucas unidades do mesmo amplificador. Eu acredito que este amplificador, o P800 tem uma potência máxima de 100w a 8 ohms ou 130w a 4 ohms.

Hi,
I am using the LX-mini speakers as surrounds in my home theater. I would like to build a center channel with the Seas Prestige FU10RB H1600-04 4" Full Range plus an open baffle midrange about 6-7 inches.

I would like recommendations for an open baffle midrange 6-7” for 80hz to 1000hz. Impedance is not a concern.

I will use the Lx-mini crossover sold in the diyaudio store and the 80hz high pass built into my preamp/processor. I know it won’t exactly match the midrange, but
I can optimize that in the future.

I can’t use the Lx-mini Seas L16RN-SL (H1480) 6" Aluminum Cone Woofers because I don’t have room for the enclosures.

Hi all,

Trying to resurrect a recently acquired IG-5218. Made the mistake of making mods before checking basic functionality but I think I’m close.

Got the meter mod and recapped. And then as I am double checking basic assembly today I notice a major departure from the manual. Bottom chassis wiring calls for a wire from solder lug K (the black sine output terminal) to spor AB on the PCB. The original owner hand wrote a note that said there is no spot AB (at least it is not labeled as such) so he ran the wire to pin one of the square amplitude pot. Seems odd he would do that unless someone told him to. Thus there is no wire to what the pictorial shows what would be point AB.

Was there a post-production edit to the assembly instructions, or did he just wing it?

Thanks for any help.
Jeff

Brian and I have been thinking through some of the design and building challenges associated with a new 8 channel design.

We have come to the conclusion that we should be bringing some very direct questions to the people who are really wanting it so that we can reason about the various challenges and associated costs in terms of both material and complexity.

We will also want to gauge the actual interest in this design - and probably take pre-orders once it's finished so that we know how many to make in the first run.

Here are some of the immediate questions:

Input:

1 - What actual multi-channel source are you planning to use?
2 - Will PCM/DSD input be sufficient? Note anything else will likely require some sort of separate input module(s) - so be specific.

Output:
1 - What are your ideas around the physical layout and casing?
2 - Do you prefer individual output boards or a monolithic 8 channel board?
3 - Do you value absolute fidelity(floating - mercury type front end) or lower cost (gnd reffed IVY type front end)?
4 - Are you likely to need SE outputs?

Control:
1 - How do you anticipate controlling the DAC?
2 - Is on-board control important to you?

Note: This is a crucial topic.

Regulators:
1 - do you prefer a tight local PCB layout with on-board regs - or would you rather have the flexibility of Trident/AVCC style regulators?

Master Clock:
1 - do you prefer the optimal layout, performance, simplicity and reliability of a local best in class on-board master clock - or the flexibility and added complexity/cost of external clock sources or Rhea modules?

Note: I am strongly inclined to opt for the local clock unless I see a very compelling reason not to do so.

There are other questions that I am sure will come up in the course of discussion.

My current thinking on output modules is to make them individual channel modules that would be neatly wired using appropriate headers and balanced wiring to the DAC and channels summed there to suite the application. Those modules will be designed such that they will have XLR/RCA connectors on board for direct back panel mounting. I want to hear your thoughts in this regard.

Now is your chance! What sort of 8 channel DAC are you looking for?

Cheers!
Russ

Hi,
recently I acquired a Revox B791 turntable in a decent condition (it looks like new). In operation it behaves very fine: It runs smooth and without any unwanted noise, and the cartridge, an ELAC with an aftermarket stylus named D793, sounds just amazingly. The best cart I've ever owned, btw.
The unit isn't withouit any issues, though: The cue operates veeery slowly in both directions, and right at the end of the record, when the linear arm's cartridge transport starts to move the cart assembly outward, the needle just slides some millimeters over the groove. This doesn't exactly sound delightful, but also might lead to both record and stylus damage. At least I'm afraid of that.
As the service manual doesn't give any hint of what to do in this case, where should I look for the reason? Is it a mechanical or an electronical issue, or both?
Best regards!

I can buy them new from Parts Express for $24.50 but was hoping someone had a pair they wanted to just about give away.

This is a nice amp, especially for small subs or woofers. It is true class A/B. Never pushed hard; just no longer need.

$100 US or best offer; I agree to pay ground shipping inside US lower 48 ONLY.

see attached spec sheet, etc from PE

Dayton Audio APA150 150W Power Amplifier

Hello,

I had both my def tech AW6500's fail on me. Appears just the woofer. Is there a generic version of the woofer? I tried through def tech and they want $100. I was curious if madisound/part express/etc had the same model since a lot of manufacturers buy other companies speakers and rebrand as their own.

Hi,

Anyone has ideas on 4 way crossover design? I've searched books and the net and hardly got a clue about it. Up to this point all readings about crossover design are focused on 2 and 3 way systems.

Peter

35w + 35w into 4 ohms.
Have a couple going spare.
Requires valve (12au7 or 12ax7), heat sink and +/-18v power supply.
£19.99 each + p+p
p+p is £4-20 to UK and £12.99 Europe and £17 rest of world.

Bought a STR-DB870 second hand, I have cleaned the inside with isopropyl alcohol, checked all connections thoroughly, nothing seems loose or degraded. However, every time I give it even a light tap specifically on the top of the amp it sends a horrible crackling noise through my right speaker, only when I tap it on the top tho, and when I use a bit of force on the sides, and when I bang the table it stands on pretty hard the same happens. And occasionally I get jump scared by it at random in the middle of a movie by the sound, for no real reason.

The noise isn't effected by changing the volume, or input settings, or any other output settings, so I think it's just the amp.

I am using it with a pair of 6 ohm 30 watt book shelf speakers, well bellow what I know this thing can handle but I am going to add a front channel and subwoofer soon enough, and make upgrades when I feel I can.

Is there any trouble shooting you could suggest for sorting this out, other than giving it another clean and tightening the screws, a little lost with how to fix it. Apart from that one issue it's a really nice amp and I would really like to keep it.

Thankyou for any responses, will be happy to post more specific details if needed.

The sticky post on how to include images has inlined images in it, but it doesn't say how to put in those inlined (and full sized) images. I poked around and tried a few tests, but I couldn't figure it out.

Thanks!
--Myles

Hello,

I am looking for 12 LM3886 or LM3886TF chips.

Thanks !

Guillaume

Please send me a message if you are interested in selling you Firstwatt B2.

Thanks.

hi all
The decoupling capactiors for PCM1704 in datasheet:
"Aluminum electrolytic capacitors are recommended for larger values."
REF DC = 47uf
SERVO DC = 47uf
BPO DC = 100uf
Is there ESR critical ? May I use the ultra-low ESR capacitors (e.g. X5R MLCC) to replace? (Sound quality is not matter, will it be unstable?)
If anyone knows the answer, please let me know, very thanks.

So a zx series came in today stuck into protection. Removed the rectifiers to test jīthe po
I have checked all the mosfets, drivers ect. And tried lifting d7, and pulling the class d card. No change.
I checked the c6, c12, c11 all test good (in curcuit) 110nF
Q110,Q111 - no short there.
The only components b i noticed damaged were the 100R wire wound resistors R63,R66 were badly burnt.
Some help would be most welcome.

Hello,

Its been a while. Working on a Xtant 3300c. Noticed that C81 is missing. Does anyone know what the value of this capacitor is?

Thanks!

I found that two IRF640N outputs (FET404 & FET6) were shorted, one on each side. I removed all fourteen to find the two, checking each one. None of the remaining twelve appear to be leaking. The TIP29C & TIP30C were checked in circuit, and are not shorted. All of the 10 Ohm gate resistors are ok. I presume the .1 Ohm, 5W resistors are ok, none are even remotely discolored.

I re-installed all of the IRF640Ns that appear ok and left out the two shorted ones at those above FET locations. The amp draws excessive current. I removed the four rectifiers and the amp idles at ~2A draw. Is that high for an unloaded power supply?

Does this amp require all fourteen of the outputs to be good and installed or are there more areas I need to look at?

I have bought some time ago, but didn't use Eton Minuetta (with SD19 TW) loudspeakers by Udo and now that i have checked them I suspect that there is a problem in crossover.
Is there anyone that can help me with crossover sheme, please?

Hi

I wish to locate and purchase a pair of the transparent polypropylene bass/mid drivers for my Castle Harlech S1 speakers. I think Castles designation may be 06.33.

Does anyone have any old stock or a pair of good secondhand drivers

Thanks

Memu51

SOLD!


For sale, 4 pcs of Peerless HDS-P830875.
Perfect for Toels Gravesen's Nomex 164 mk-2!
In fact, they have been used for that project, and are still installed in their enclosure...

Since I think they will be easier to sell than the whole system, you find this sale topic! Moreover, I have some new projects where to use the tweeter and most of crossover parts, so... 😀😀😀

I can sell:

- 1 couple: 100€ + shipping costs
- 2 couples: 180€ + shipping costs.

I am based in Florence, Italy and I can ship all over the world; obviously the destination will impact on shipping prices, though... 😀

Just to clarify: they are used items, but in perfect shape! They just sing...
I still have the receipt and their plastic protection covers.

Waiting for your contacts, meanwhile, stay safe!
Giacomo.

Hi fellow DIY'ers!

For several years i have been enjoying all types, shapes and sizes of boxed speakers, but approximately a half year ago i started to do some research on the phenomenon known as dipole speakers.

2 months ago i came across PureAudioProject which has developed a open baffle system consisting of a HW kit which enables one to easily assemble the baffles almost without the use of any tools.

I decided to drop them an email and surprisingly Ze'ev, the founder behind PureAudioProject replied me the same day and showed a great interest in my DIY project. Our correspondences went on for a few weeks and Ze'ev came up with a new design suggestion for the construction based on a newly designed and manufactured woofer from Morel, namely PAP1075. Shortly he made the prototype of the speakers and the results were mindblowing (or is that earblowing?), neverthless i went ahead and decided it was time for me to try out this unexplored territory.

Reason why i chose this approach over building everything from scratch is simply because i want to achieve a elegant result without using infinite amount of time which i dont have as a working student.

I will keep this thread updated with images from the build process.

What i have in the pipeline right now are following:

TODO:

• Receive all HW components
• Receive all XO components
• Finding a wood source for the baffle panels
• Processing wood
• Assembling the baffles
• Build last monoblock for amplifier
• Test passive XO setups
• Test active XO setups

*(Bold text in listing means the task is completed)

The amplifier is based on the TAS5630B module from TI, and the PCB's originate from a fellow member on this forum.

I hope anybody reading this thread is as excited as i am. 🙂

Stay tuned!

LINKS:
The birth of PAP1075, 10″ Open Baffle Bass and Mid Woofer
Chapter 2: Passive Crossover

I finished building my TU-8600S amp over the weekend. I very carefully followed the instructions in the manual and the tips that Victor gave me. I double-checked all solder joints and component placements.

It worked the first time that I powered it up. It is dead quiet when the volume is turned all the way up with no music playing.

This is my first tube amp and is by far the best sounding amp I have ever owned.

I ordered all the upgrades. I have attached pictures of the Takman resistor preparation, orientation of the V caps, wire routing of the primary connection on the Lundahl OPTs, and tubes used.

I will be rolling tubes in a few weeks, after I have gotten familiar with the sound of the amp.

Thanks again to Victor for the great service he provided to me and his great dedication to our hobby. I appreciate that he brought this 300B amp kit to us and made it so easy to get the upgraded components.

Allan
Round Rock, Texas

Hi,
I'm posting this here because my system is built around a Modulus-86, and the build thread for that particular amp is in this forum section if anyone feels that it's in the wrong place feel free to move it.

I should start out by saying I'm incredibly happy with my system, its a fairly modest set up built around accuracy and transparency (hence me building a modulus-86 last year), so it's not that I'm not satisfied with the system, I'm just curious about how impedance matching may (or may not) have an impact on my system.

If I get the ball rolling with an overview of my system, I'll try to include the input and output impedance of each device in the chain, then hopefully people could explain to me if and why there may be anything that could adversely affect the performance of the system.

My primary music source is a hi quality streaming service running on a laptop, the DAC connected to the laptop is a JDS Labs O-Dac Rev B. I cant find the specific output impedance but looking at the specs i found this "Maximum Output Line Out 100K - 2.1 VRMS"

The DAC goes through a passive preamp which I use for switching between 2 sources and controlling the volume of the output. It's a Schiit SYS, according to their specs it has an input impedance of 10K ohms, and the output impedance is 5K Ohms MAX (I'm assuming they state the MAX because this dependent on where the potentiometer is set - which is what I'm really interested in)

The output of the passive pre then goes into my Adam T10S powered subwoofer. The sub has a crossover which I set at 85Hz and passes everything above to the madulus-86. I'm not a huge sub bass person, I just have it on quite low just to offer a subtle floor of sub and take a bit of duty off my speakers, so they can shine in the range they do best.
Heres where it get tricky though, as we dont have any impedance ratings for the input and output on their specs ADAM Audio - T10S Active Subwoofer For T Series Studio Monitors

From there the high passed signal goes to the modulus-86 amp, although tom's site doesnt specifically state the input impedance it states the input sensitivity 1.8 V RMS 40 W, 8 Ω

Finally, the amp is powering a pair of Magnepan LRS (Fantastic speakers by the way, they deliver that "in the room and invisible" performance that want from music) They are rated at 4 Ohms, which i know the amp has no problem dealing with (even less so now I've added the sub, the amp doesnt really get more than just warm)

So, I know thats quite a lot to digest, so if you got this far, thanks for reading.
I guess the main thing I'm intrigued about is the passive pre amp and if the potentiometer will make an audible difference if I'm setting it as half way (50% attenuation ?)

Thanks again.

Tom

Thank you to anyone taking time out to read this post and any replies to it, its much appreciated.

Having had to take apart one of my semi omni directional speakers to bits earlier this year to replace a damaged woofer, I also took the opportunity to replace the original circa 1991 tweeters, resistors and capacitors with modern replacements with the same values.

Everything worked out fine and this gave me the confidence to move to the current phase which sees me replacing the original two tweeters and adding a third to hopefully give a fuller omni experience.

The new design will be as follows, 2 x Monacor SPH220HQs 8" woofers in an isobaric configuration directly wired to one of the three sets of binding posts, the woofers have no crossover.

The left & right firing tweeters are Visaton G 20 S and the forward firing tweeter is a Visaton G 25 FFL. The tweeters will have a basic first order crossover with the crossover being in the 6 khz region.

My friend has calculated the two G 20 S wired in series to the second set of binding posts will need a capacitor in the order of 1.63uf and the single G 25 FFL wired to third set of binding posts will need a capacitor in the order of 3.3uf.

But here's the $64m question, what size/value resistor do I need to include ahead of the each capacitor/s.I have done my best to search google and various forums for a formula or calculation but all that's happened is I have ended up dazed & confused.

All advice is welcomed because this is I think the last piece of my speaker redesign jigsaw. All the best Paul B

MONACOR: SPH-220HQ

G 20 SC - 8 Ohm | Visaton

G 25 FFL - 8 Ohm | Visaton

I'm just about to implement these units with my 3 ways speakers and was wondering whether users of these units are using the Hypex software or REW?

Thanks.

I want to customize the existing preamp using signal relays and the existing IR remote control hardware. Unused functions on the remote will be converted to another purpose. This is a one off custom DIY project.

I have four remote keys that I want to each control one relay in the preamp. We are talking small high quality DC coil DPDT pcb signal relays.

I have the schematic for the remote receiver and decoder, and have located a signal pulse from the 5V remote decoder IC that goes low for 150ms on each key press. Each of the four keys has a dedicated control line for this purpose. I was hoping to find a control line that latches high or low but I can only find a pulse signal. I want to use that pulse to toggle a relay, the first time the remote key is pressed the relay energizes, with the second press it de-energizes. I need a simple circuit that converts the 150ms pulse into a latched high or low drive signal that I can use to drive a transistor which in turn drives the relay. The part that I can't figure is how to derive the toggled latched output from the pulse input. A simple thru hole TTL or CMOS cct is what I have in mind, something I can make on perf board. What do you recommend? The IR remote receiver circuit uses the 5V TC9134 chip, Toshiba I think, 1990s vintage, the control lines I am thinking of using are the outputs type SP.

Ted in NY

Pair / Usher 15HM
Price 800Euro + Shipping + Fees (PayPal)

Condition: Like new. One of them was used 5 minutes.

SO the band Im in have been using this little Fender Passport PA for practice with good results until recently it stopped working.
When powered on the protect light just lights up and no sound comes out. It does this with nothing plugged in as well (speakers mics). What would be a good starting point to try and repair it?
Thanks!

SOLD






I'm selling First Watt B1 R2 buffer line stage.
condition is very good. No scratches, dings, marks, etc and perfect function.
item is in south korea but will ship to wordwide.

$800 include shipping to wordwide.

47 Laboratory 4706 Gaincard 25W version 220V
I bought it from japan one years ago.
Perfect working order. wihtout original packaging.
item is in south korea but will ship to wordwide.
free ship to world wide.

$2,000 include shipping to worldwide.

I was surfing around the net looking at power supplies, soft starts, and speaker protection circuits and I came across this,



Power Supply and Protection Circuit | Connex Electronic

Has anyone used this?

It looks all in one...

Hello!

I am planning a two-way speaker with the ScanSpeak D2608/913000 tweeter in a waveguide and a ScanSpeak 22w/4534g00. Therefore, I made a test-piece on my CNC-machine, and am asking for comments on the frequency responses at different angles.

The sidewalls of the waveguide enlarge on the contour of a circle with 225 mm diameter. The waveguide itself has a diameter of 225 mm and is 36 mm deep. Find attached an image of the waveguide construction and the prototype.

The measurements shown are gated, unsmoothed, measured at 1 m distance, and at angles from 0 to 90 degrees from top to bottom.

I am a bit concerned about the lack of directionality between 2 and 8 kHz. The 0, 15 and 30 degree measurements are a bit bundled up. What do you think?

Thanks for any comments!

Does anyone have a good copy of a schematic with parts list for Crate G40C guitar amp ?



The one I have from the web has unreadable parts list, and scribblings on it.


Thanks.

Laptop speakers do not sound very good, especially the lower end laptop speakers. I am surprised no one has come up with a laptop with subwoofers..

I have put together a set of open baffle speakers as shown in the image. These are taken from a PC speaker set that has long been dismantled. The speaker reads 4 Ohms. Originally used with my LM386 amplifier board but the LM386 is just too much for the low volumes I need to use without disturbing anyone. This is extreme near field, and is better than headphones. In fact, low volume speakers are a real advantage in a working environment, where others cannot be disturbed by the music during their phone calls, video conferences etc.

Here is the question: can these speakers be safely connected to the output of a laptop or a speaker (many years ago there used to be unpowered PC speakers)? . I have used a set of unpowered speakers many years ago on my desktop PC which has long since either given away or broken.

It all comes down to impedance. The typical resistance of a earphone for phones ( I measured mine) is 30 Ohms. Now this is not the impedance, but can function as a lower limit for impedance, since the formula for impedance is:

Impedance = SquareRoot(Resistance^2 + Impedance^2)

Instead of connecting a 4 Ohm speaker across the phone jack output, I can connect a 30 Ohm resistor in series with the speakers, and maybe a capacitor to keep out extreme low end. I tried this, and the sound volume is acceptable when boosted with Audacity (bass and treble) and distortion is not really a problem.

Does this all make sense? Anything I have missed? Anyone use this?

I am now presenting my KT150 SE design for your comment. I have turned away from the 300B all dc coupled to kt150 se as the 300b I design would be quite massive and I want my first build to be manageable. I still keep the dc couple design by using 2 power rail for output and preamp circuit. Nevertheless I added the 2nd stage preamp which is ac coupled from the 1st stage for user to meet situation where extra gain is required by toggle a 2p2t switch (for each channel).The ECC88 along can provide 60V swing required by the kt150 from 5v p-p input which is around 1.77Vrms input signal. If 80V swing is required for driving 300B than the 2nd stage is certainly required unless your line level has at least 2.4Vrms output. Now just let me provide some key figures of the amp:

1st stage : 1/2 ECC88
Rk=370ohm (This value has been compared to , and should be close enough, to the value chosen from referencing the loadline (Ra+Rk=10k), finding the intercept of Vg and calculate the ratio of dVg/dIa in order to determine the value which hope the Rk can fully compensate the Vk to maintain the Va due to tube ageing or minor dc offset from input signal. I think a stable Va is of much importance to the next dc coupled stages as that affect the Vg indeed. Please share your view on this.). A lower resistance volume pot (20~25k) is chosen to meet -0.1db at 20khz for this stage after consider the miller capacitance, and still high enough for low impedance line level output (600ohm) from modern source.

2nd stage : 1/2 ECC88
This stage has unbypassed cathode resistor to lower the gain and increase headroom for the input from 1st stage. The output impedance will be higher compared to the one with bypassed cathode resistor but still the value is <6.3k, which is enough to meet the -0.1db at 20khz for driving the kt150 (assume the total miller capacitance is 170pf).


Output stage: KT150
No grid leak resistor is required I think as the dc coupled previous stage has DC resistance <25k which is much less than the min. requirement of 51k for fixed bias. The OPT is 4.2k ohm which is suitable for KT150 and also 300B, allow subsequent modification (320v tap is therefore prepared for 300b or other lower power tube). Ultralinear tap will be there on the OPT and wired as option for user to choose triode or ultralinear mode by a 2p2t switch (both channel). The KT150 will be at Va~540v Ia=120mA, Vg=-60. The "fully compensated" Rk is around 650ohm but it is way too hot and also not necessary to maintain Va as it is the last stage so the 200ohm is chosen will still provide some compensation and with acceptable power consumption.

The operating point is initially set for triode strapped but I look for the ultralinear curve and note that the operating point should also be ok under ultralinear mode.

Heater:
The preamp stages heater is now wired as AC powered but it is likely to switch to DC powered to minimize heater hum for these sensitivity stages. The kt150 heater will be AC powered with artificial ground and elevated but not a hum pot, which I guess is already enough for low amplification IDHT.

Tube rectifier:

6CJ3 is selected given its current output capacity for meeting the KT150 as will as its better look (no connection tap at the top of tube like 6d22s). The input capacitors are limited to 47uF which is lower than the limit of 6CJ3 and 6CA4. Capacitor value after that has no special limit as I can see from various materials and so they are chosen to achieve the desired ripple voltage target using PSUD2. A 47uF capacitor is connected from the filtered output tube power rail to the output tube cathode resistor as I learned this tech from an article from TubeCAD which can offset the B+ ripple on the output tube. Nevertheless I think a better filtered power supply is always superior to this tech as this induced B+ ripple to the cathode may mix with the signal and create intermodulation product.

NFB:

I think it worth the effort to provide option of adjustable GNFB from the speaker terminal to the 2nd stage preamp, as there is only DC coupled in between which should allow min phase shift problem when dealing with NFB.

Remarks:
I guess a potential divider may be required before c7 to lower the signal so that the volume will not jack up to much when toggle on the 2nd stage and also allow better volume adjustment.

Please share your view on the circuit, many thanks.

Good morning, I have in my possession a couple of midrange from the massive PK6S, but when looking for these parameters they are not in the box, any suggestions to make a sealed type acoustic box.

This is two amplifiers combined in push pull. The main power amp is made of open loop current amplifier T4,T5. The bias is adjusted by R5, 1.3A and the transconductance by R7. The second amplifier is also a transconductance with feedback to provide a low impedance output.
This is a quick feasibility circuit of 10w, with mosfet it is about 0.05% THD and the double with bjt version.
Hayk

This phono preamp is based on the circuit for an ultra low noise RIAA phono preamplifier in Texas Instruments Application Report AN-222 “Super Matched Bipolar Transistor Pair”. The matched transistor pair replace the input transistors of an opamp. The circuit was designed for the LM394 transistor pair, which was discontinued. My board uses the (pricey) Analog Devices MAT12 replacement. The IC is an LM318, as noted on the application report.
The raw power supply is 6L6’s version of the Pass Pearl2 supply, and a Jung/Diddden Super Regulator coverts it to +-15V for the phono board.
This is a very smooth, quiet preamp.
Dimensions: 4.25H x 10L x 8.25D (inches). That is a laser cut LP of the Seattle skyline on the front.
Documentation and extra pcbs (raw ps and phono) included.
$100, OBO, shipping to CUS only

11/19/2020 ***SOLD***

Hi,

A friend brought his original Pass Labs Aleph 3 to me to check out a couple of weeks ago, and when I peeked under the hood I could see some of the power supply filter caps had crowned tops. The little 220uf caps all tested high for ESR, so I changed all the electrolytics out for the original factory values. Now that friend has brought me his Aleph 30. The caps in this amp don't show physical deformities, but since it's a 17 year old Class A amp and easy to work on, I'm going to replace them.

The Aleph 30 is an improvement over the 3, so I'm curious about the difference in total capacitance in the power supply:

• Aleph 3 stock caps: Panasonic UP 25v 22,000uf x 8 = 176,000uf
• Aleph 30 stock caps: Panasonic UP 50v 10,000uf x 12 = 120,000uf

Is the reduction in total capacitance relevant or was the value in original Aleph 3 simply overkill?

I've gone through various replacement options offered by Digikey, and have narrowed my choice down to the following:

1. CDE 380LX 50v 10,000uf x 12 = 120,000uf
2. Nichicon LLS 35v 15,000uf x 12 = 180,000uf

There are no 105c rated caps that will fit in this application. I understand the 50v rating is higher than needed, so would the additional capacitance offered by the 35v Nichicon caps a point in their favour? I know they are both well respected brands. Or am I overthinking a trivial detail?

I'll use Nichicon KA for the 220uf values.

Thanks in advance.

Hello Everyone!

This is the first of several posts I’m going to make in this thread. This is the first time in a few years that I’ve posted on an online forum and will try not to make a mess of it.

Background

This is yet another DC-300A II refurbish experience that in my case was world’s easier than the Amazing Effort by Shawn 10 years ago. This is because I cheated and bought one that was already in good condition. It was sold initially to a home owner in Canada that made its way to the US, then finally to me a few weeks ago via FleaBay™. I spent (2) days on it and a couple of weeks deciding on and waiting for parts orders. The one thing that will be different about this post is that I’m a measurement nut. Audio, to a large extent, is a means to an end of empirical learning for me and if you’re foolish enough to follow along, I bet you too will see some stuff you haven’t come across before. 🙂

Though I’ve finished the refurbish, I haven’t listened to the amp yet. I was afraid to connect it to my loudspeakers prior to measurement and afterwards figured the "before" listening experience wouldn’t be indicative of a new OEM unit anyway. I’ll add a post to this thread in a week or so after doing some serious listening and see if this amp really earns its broken glass with good bass reputation.

Per Shawn’s and a few others comments both here and on the Crown Forum, and the good initial condition of the amp, I chose just to upgrade the electrolytic and ceramic disc capacitors and leave it at that. The 1N270 germanium diodes used in the limiting circuitry work properly, so I left them in place though I did buy spares for the future in case they become unobtainum.

OEM Parts to Upgrade

View attachment DC-300A II OEM.pdf

Replacement Parts

View attachment DC-300A II MOD.pdf

And for completeness, here’s a link to the Service Manual and the Owner's Manual.

Finally, as will be seen in following posts, what’s inside now matches the pretty outside:

Hi
I made some digital interconect cables from special, very flexible, 75 Ohm video cables and compared them with regular high quality interconnect cables on my scope, the selfmade digital cables show faster edge rise time time on the digital trace, 7 nS instead of 21 nS, did anyone else measure that? Must try and do some listening tests....
Cheers, Tom.

Hello forum members

This is my 1st chip amp construction thread ... LM1875, a little project that has been kicking about for a while. I don't really need to make one, but was attracted by the simple construction that could be achieved ... and for some reason really liked the PCB layout with noise cancelling ideas applied to the track layouts that seems to be a new skill amongst PCB designers .. so will allow the pictures to tell the story
I decided to make my own post instead of high-jacking another members post ...

So mainly a question out of curiosity, but is there any problem with using a single-ended output transformer with 5K and 8K taps as an ultralinear setup with a KT77 power tube? Plate voltage would be in the 350V range and transformer is rated for 15W

I realize it's not the standard 40% ultralinear tap, but I have this transformer and tube sitting around and was thinking about building something just for experimentation sake, because if it worked reasonably well it might be cool. The KT77 datasheet says it can be used as a tetrode but screen voltage should not exceed 300V (while design max is 600V for ultralinear). My datasheet has little to no info on a single-ended setup, so basically I was just checking to see if this sounded like a catastrophic failure waiting to happen or potentially doable.

Thanks.

Hi, I have a few old transformers like these probably Partridge ones where the varnish has chipped. It would be nice to patch them up, for aesthetic reasons, but what old varnish is it, and even available in the 21st century.
Thanks.

Good Evening everyone. I am building a few boxes and I read on one of the building blue prints. It said Don't use egg shape foam for the inside of a box for sound absorbing for the back sound waves. Why not? I have never had trouble with this egg shape foam before? I was told to use cotton or wool felt instead? Why not Acousta suff poly fill? So on to the next question? Binding post made of 100% copper sounds better then brass? I keep reading this? Does it really make a night and day improvement? I just wanted to get every ones thoughts on these clams? Thanks for your help. Jeff

Hi,

Really a question out of curiosity more than anything else. Today I was messing around with a piece of hi-fi which had a faulty internal PSU and wanted to change it for a spare and to do this I needed to swap a 4 core connecting cable which was soldered into the PSU.

I first tried unsoldering the cables using a small electronics specific soldering iron which I think is 60 to 75 watts - the type with a conical point. The solder just didn't want to melt so tried my Weller soldering iron which is probably a couple of hundred watts. Again couldnt get the solder to melt even though the cable was getting too hot to hold where I was gripping it a few cms from the joint and the sheath was almost melting!

Playing with circuit boards is not something I do very often, so maybe my technique was wrong, but as I said there were 4 wires and not one came out easily, even using the Weller. So curious as to whether some manufacturers might use higher melting solder?

Any comments appreciated.

Alchad

Here is a (as I can call it) very custom version of the DSC DAC for sale.

Price is $1.3k (~1.1$k for the parts + assembling fee) + shipment.

It is based on the DSC v.2.5.2 board + PPY's reclocker (NDK SDA) + BBB + my output transformers + relay volume attenuator with RC.

All the boards (excluding volume control) are powered from linear K&K PSUs (LT3080) and shunted with ultracaps.

This DAC can accept the DSD stream only (not PCM). The best possible way is to use the HQPlayer, to which this DAC will be connected through the LAN (RJ45 on the rear - input interface of the BeagleBoneBlack SBC) as NAA endpoint device. Roon-bridge is possible too.
Disclaimer 🙂 Due to complexity of the connection type and irregular usage way for this DAC, I can not positioning it as a "branded" DAC. It is better to regard it as a finished DIY-project. I can not give to the buyer any long term warranty in this manner. The buyer should be ready for such kind of DAC. The dedicated server with HQP (Roon+HQP) is prefered for connect this DAC to.

Regarding the sound quality. I can say that this particular DAC paired with HQP4 (ASDM7EC x256 modulator) easily outperforms the PSAudio DirectStream Dac.

I have a Hifonics Hercules 35th Anniversary Edition model H35-3000.1d that would go into protection mode when too much current is supply and would stay solid green when little current is applied but no sound whatsoever. Installed into my car to see if it was just the power supply that im using to power the amp was making it go into protection but the lights would flash from red to green. Opened up the amp and everything looks fine. Nothing looks blown. Could anyone help me? Thanks.