Emotiva A-700 Seven Channel Power Amplifier

Great condition. No longer needed as I am liquidating my multichannel setup and going back to basic two channel stereo.

Power Output with two channels driven is 110 watts RMS / channel; 20 Hz - 20 kHz; THD < 0.1%; into 8 Ohms

If interested I'll be glad to send photos.

Asking $350 plus shipping.

Hello everyone. I hope everyone is still doing well during these times.

I have a couple edcor 7.6K UL push pull transformers that I would like to turn into a small amplifier.

I am looking at using a single stage 6E5P push pull amplifier and I would like to give UL a shot with these tubes to see what sort of power I can pull out.

The problem is that I can't find any UL curves for this tube, so I can't figure out what the bias point should be.

If any of you could point me in the right direction, or if you guys think UL with this tube might be a waste of time, please let me know.

Don’t order parts on eBay, I’m convinced they’re all counterfeit. You can see the dies on these supposedly genuine transistors aren’t even 1/4th the size of the originals, and though the amplifier seemed to work OK they blew and torched a receiver I repaired at only modest volume levels. So learn from my mistakes, even if you don’t think it matters, it really does- even at low power levels.

I am looking for a us amps 500a . I had one back in the day and I am doing a new build and trying to find one . Let me know what you got

Seems as if the mid-1990s-designed Philips tda-1305 has gained a cult following in the Chinese diy community, and maybe certain UK high-end manufs, too.

Current AMR cd player that uses tda 1305:
CD-777 SE Compact Disk Processor by AMR Audio

Legacy AMR cd player (used tda 1541a; AMR later switched to tda1305):
CD-77 Compact Disk Processor by AMR Audio

Legacy Naim CD 3.5 CD player from 1998:
Naim CD 3.5 CD player | Stereophile.com

Various low-cost TDA1305 Chinese kits on Ali and eBay including this USD $31 2x TDA1305 device:
Dual TDA1305 DAC chip + CS8412 Digital reception + CM108 USB Fever Class HIFI DAC Decoder board With usb fiber coaxial input|dac decoder board|dac decoderhifi dac - AliExpress

....and this USD $30 TDA1315H+TDA1305T device on eBay:
TDA1315H+TDA1305T Decoders Fiber Coaxial To AnalogAudio Signal DAC ZJ-64 | eBay

And indiv. 1305 chips are readily avail and dirt cheap on eBay and Ali.

tda1305 datasheet:
http://www.acoustica.org.uk/t/naim/data/TDA1305.PDF

This Magnavox-branded twin triode was pulled from a 1960's console. The power amp is an 8601-10, but this was pulled from the tuner/phono section. I can't find anything etched on it. The silkscreening says "MAGNAVOX", "Made In U.S.A.", and some numbers and letters I'm having a hard time reading. I don't really care about brand, but I'd like to know what part it is!

The plate structure is unusually "bulbous", and the plate tabs above the top mica are pretty distinctive. Any guesses as to what it might be?

This schematic makes no sense, it seems like grounding one end of a wire directly and the other end through a resistor and capacitor is useless.

here's the Mullard datasheet: http://www.mif.pg.gda.pl/homepages/frank/sheets/129/e/EL34.pdf

here's the Phillips datasheet: http://www.mif.pg.gda.pl/homepages/frank/sheets/030/e/EL34.pdf
=================
1. According to Philips (top of page 7), I need to connect grid2 to plate and I'll get a triode.

BUT according to mullard (page3), to get a triode connection, it's grid2 to plate and grid3 to cathode.

so which is right? It is possible as well that I misread the datasheet.

ps. I've seen replies were people have recommended the Mullard way but Philips must know something if they are recommending it differently.

2. I've seen replies where people have suggested a 100ohm resistor between plate and grid2. But I was looking at the mullard and philips datasheets and it seems I only need a piece of wire to connect the two pins.

what is the purpose of the 100ohm resistor?


Thank you for the help

I'm simulating the box of the FaitalPro 18xl1600,
it will be used in a 4-way hifi system from 30 to 100hz
this driver has a 176 liter vas and a 32hz fs.
The best result that is
vb = 190 liters
fb = 32hz
f3 = 32.5 hz
is it possible to have the VB greater than or equal to the VAS?

OK so I thought I'd build something different from an amp. I had given up with getting the coils for the IF, but then came across this kit.


Vintage Valve Tube FM Radio DIY Kit Stereo Receiver Frequency Modulation Board | eBay


Its from China and probably a copy of something. However its comes with newly wound double tuned IF coils and a double sided PCB of very good quality with ground floods on both sides. The tuning cap is a reused unit but I would like to change the design to synthesised varicap tuning.


There's a schematic here:
IWISTAO Tube FM Stereo Radio Tuner Finished PCBA Preamplifier Version No Including Power Transformer HIFI Audio 110V/220V DIY|hifi wire|transformer currenthifi component - AliExpress


I don't have consent to put in the one I have.


I have test equipment to get the thing up and running.

Wasn't sure where else to put this so hopefully this works...


I recently had Lars Risbo of PURIFI Audio on my channel to chat. To those of you who missed it, a link is below. Lars provided an overview of how drive units work, insight in to what makes PURIFI drivers so exceptional, and an exclusive look in to the hardware and software used in their R&D work.


I know I speak not only for myself but the community as well when I say "thank you" again to Lars and the rest of the PURIFI team who helped facilitate this and offer some insight of their own via the chat. Maybe we can do this again in the future.


Live with PURIFI Co-Founder Lars Risbo! - YouTube

I decided to design the LM1875 for its best. First I will study the character in detail , sort out the problems to resolve and bring solutions to get highest quality possible. It can be paralleled and bridged, it can be composite or not.
Hayk

Has someone experimented with the mini-aleph side-to-side with a pass aleph-3?

I wonder how the differences in sound quality can be described between these 2 same designs using one pair instead of two pairs of output transistors.

I guess there will be some extra smearing in the sound when using pairs parallel. But otherwise: why should super amps using 24 pairs or more in parallel sound so good?

Best is:
* using same components quality.
* using same idle current and voltages.
* judge within same power envelope (say first 10 watts)

Or in other words: when no more power than 10 Watts per channel is required (easy 8 ohm load with high sensitivity) would the mini-aleph always be a better option, not only theoretically but also tested in practice?

In case anyone has any spares...

HI, good evening,
I should buy a quartet of these tubes, I read a little here and there on the net to clarify the versions.
Discarding (???) the Reflectors that all those who have tried them between the various versions / brands / place of construction say they sound a little "solid state", I would be directed to those produced in Voskhod, therefore with the "rocket" logo.

Since there are several vintages and different getters, EVs, etc ... is it not by chance that someone among you has experience on this and can advise me by making a sort of "lineup"?
I also see that sellers mention "gold grid" or "silver shield" .....

Thanks! 😀

Hi amigos,

This is probably the first shots of the Berihinger A800 Class D amplifier.
I heard lots of great reviews about this Amp and I tried to ask to Berihinger customer serice some info. about the audio chip : they were not allowed to share those technical informations. I also asked to Thomann in Germany but the same... this is like a secret )

So, I started the adventure and decided to share a little review.
Keep in mind that this review is based on my discerning musician ears. I have been playing drums for many years now and my father is classical guitarist as well. So that I can compare, I specify that I have several amps. (High end AB amp, TPA3255 Amp Purepath, TK2050 Tripath)

My equipments :

- Audiophile Audio Player
- Tube DK TP01 Preamp + Sylvania EBE6W NOS Tubes made in the USA
- HD Audio 24 Bit Playlist : Jazz / World Music / Voices Female + Male
- The Preamp is connected via XLR balanced inputs
- Hi ends Floors Speakers 3 way / 93DB @ 8 ohms handmade in France

Berihinger A800 spec :

Output circuit type Class-D
Circuit protection Short circuit current, DC fault, AC fuse, thermal cut
Distortion (4 Ω @ 150 W @ 1 kHz) <0.08 %
Damping factor >160 @ 8 Ω
Frequency response @ -10 dB below rated output power 20 Hz to 20 kHz, +0/-1 dB
Frequency response @ -3 dB 10 Hz to 30 kHz
Signal-to-noise >100 dB (A weighted, 20 Hz to 20 kHz)
Voltage gain @ level control max Balanced: 30 dB / RCA: 41 dB
Input sensitivity @ level control max XLR: +4 dBu / RCA: -10 dBV

Sound Stage :
Compared to my AB high end amplifier, I would say that the A800 has clinical or even a surgical sound, extremely well balanced with a formidable precision in the low ends. This is pretty typical with Class D amps but I have to admit that the balance between all the frequencies is quite exceptional ! Audio image is really great (this depends also on recordings and tubes)

Musicality :
The musicality is a little to the detriment of the accuracy of this class D Amp. Question of taste probably.... With the A800 you will really hear some suprising details (sliding guitar strings, articulations on the snare etc)... It is as accurate as the TPA3255 maybe better to my ears but a little less warm than my AB amp.

Dynnamics :
Excellent ! The music really live : the amp has a lot power. Listening is not tiring really amazing. The range of how gently or strongly are played the instruments is clearly noticeable.

Noise / Signal :
AMAZING ! absolutely dead silence between songs even with my Volume control @70%.

Conclusion :
For this price, I think it is impossible to Out perform this Class D amp.
For me it is clearly an Audiophile amplifier that performs as well as a 1000$ amplifier. Now let the scientif measures confirm this....

Pictures from inside and I will let the specialist analyze the electronic part )

I've recently discovered that the late Mr Siegfried linkwitz talks about stereo surround sound Surround stereo system

Basically adding a decorrelated delayed signal to the original untouched stereo playback, I've tried it using an old denon receiver using the Prologic IIX to extract the ambiance and delayed it 20 ms, the speakers used for the purpose starts rolling off around 1 khz , to avoid localization cues and they're omnidirectional in the horizontal plane, the result is excellent, once the correct volume is found, i'm noticing substantial improvements, the soundstage is wider when called for, more spacious and the sense of envelopment is increased.

I've been reading about Watson WATSON-Stereo_Expansion_Loudspeakers
again something Mr Linkwitz talked about and wondering if i can add it to my existing system, i'll have to get a few missing pieces so it s not so easy to just try it.
would the ambience interact negatively with the watsons?
what do you guys think?

I'm thinking about that ubiquitous situation of loud dance music in those tunnel-shaped urban clubs... usually a headache inducing mess.

Seems to me a single constant directivity point-source main, flown at the center rear above the stage and angled down at the dance floor, would do a much better job than a pair of narrow-pattern tops stuck on the side walls. The mains crossing @ 80-100hz to subs.

What are the implications of DJs or live bands with L+R mixes (maybe real "stereo", maybe just decorrelated L+R channels) being sent to this cyclops of a PA system? My feeling is that there will be some signal cancellations from summing channels in the speaker, but that the lack of reflections/cancellations in the room will far outweigh this for the folks on the dance floor, in the lounge, at the bar...

Any thoughts or experiences?

yes I want to buy 4 J113,matched.
If no one has them matchedn I´ll buy unmached...🙂

Hi,

This is my first foray into the DIY World. I'm trying to design a 2 way similar to the Zaph ZRT but with illuminator drivers instead of revelators. Looking for feedback on the steps involved in designing a speaker.

Primary objective: An impedance not lower than 4 ohms minimum to play well with a wide range of amplifiers.

1) I've picked the drivers: D3004/66200 and 18WU/4741TOO.

2) Gotten close to a flat FR in vituixCAD with crossover design. I don't like the tweeter playing down so low but have not been able to design steeper filter that works for me. Couldn't get rid of the 2 dB bump around 200 hz so I gave up thinking baffle step might help me with that.

3) Tried using the enclosure tool within VituixCAD. Bass reflex 2.5 cu ft. or 70 liters, I've attached the screenshot.

Problem is I designed the crossover with the 87.5 dB/w sensitivity rating of the mid range and brought down the tweeter a few dB, but the enclosure is now giving me and average SPL of 91 dB for the mid-range. Should I bump up the tweeter again? Or there is some other solution behind this?

Also Is this driver really going to give me a -3 dB of 25 hz? Seems too good to be true. I'm pretty confused so please point me in the right direction.

Your help will be greatly appreciated!

I've been doing a little house remodeling and it's finally time to do my dedicated library, and listening area! 12x15' 180 sqft of slam packed literary and auditory bliss.

Walls have a fresh coat of paint, floor is newly carpeted. Doorway is open but can easily be covered with some heavy-duty window treatments, same as the 9Lx6H' window. The mother-in-law does custom drapes and sewing for a living and can make me some nice 3 layer heavy duty drapes at materials cost.

This space should be able to at a minimum comfortably seat two adults and preferably four with an emphasis on comfort. Not really "critical listening" but do like to enjoy high quality audio. I'm a part time cabinet maker/woodworker so shelves, component stands and vinyl storage will all likely be custom built to maximize space.

My first thought was speakers along wall B, seating position 3 feet off of wall D. This limits me to a roughly 80" couch or a few wide chair's, enough seating for two adults. I'm now leaning with larger sectional back 12-15" off of C wall with extremely heavy duty drapes covering the windows. This way I can get four to five adults seated comfortably. This configuration puts the listener five to six feet away from the speaker, is this borderline near field listening?

Anyway that's enough for tonight, I feel like I've written a damn novel. Any and all ideas are greatly welcome and highly appreciated. This will be a slow project, and I'll try and keep some pictures and updates coming as it happens.

Thanks,
ndp

Hello everyone.
I am now finishing the construction of two stereo monaural amplifiers Aleph5.
I would like to use them in the future to drive bi-amping full-range speakers from the Troels Gravsen workshop:
Jenzen CA
I want to use a DAC with storage in a local NAS as a music source.

Now to the question - which Pre-amp to use?
I know that Aleph 5 is not powerful enough in terms of bass, but I would like to take advantage of the low band gain using BIAMP 6-24 ACTIVE CROSSOVER.
I can go the route: DAC -> any pre-amp aka. B1? -> CRS.OVER -> 2x ALEPH5 input -> Subbas + fullrange input speakers.

I'm still undecided with the choice of speakers, but I'd like to keep the requirement for a full-range system, possibly with a bass-horn baffle.
Given that the system will also be used to listen to home theater, I am considering adding subwoofers.

However, I like to hear the experiences of others.
The bottom line is, choose a pre-amp capable of feeding enough as a crossover, as well as a bi-amp connection of Aleph 5 amplifiers.
Thanks for any feedback on both the pre-amp and speaker selection

However, I like to hear the experiences of others.
The conclusion is etak, choose a pre-amp capable of feeding enough both a crossover and a bi-amp connection of Aleph 5 amplifiers.
Thanks for any feedback on both the pre-amp and speaker selection

Hello guys,

last year I finished successfully my TABAQ build, thanks to the help received from the community.

I learned a lot and I would like to progress further with the second build.

The idea is to do three ways with separate boxes and active crossover PC based with an Okto DAC:

1. Woofer up to 120 Hz ~250 Hz
2. Full-range from 120 Hz to 5 KHz ~250 Hz
3. Tweeter from 5 KHz

I need your help defining the boxes and the speakers, because I lack knowledge. These are my restrictions:

1. I like full-range sound for mids but I prefer tweeters for high frequencies. I will start with a simple WAV setup first, then eventually go for the tweeter if I'm not satisfied.
2. The boxes will be stacked up, but I can think about doing a single sub and moving it away. I guess this will require crossing at ~ 80 Hz though.
3. Budget per speaker, possibly below 100 €. The cheaper the better, I will compromise if I need to.
4. I'd go for sealed boxes if dimensions and frequency response allow it. I would like to go deep to 30 Hz at least.
5. My listening includes rock, metal, electronic, ambient and jazz.

Waiting for your advice! Thanks in advance, cheers

Hi guys, I recently bought an orion 275XTR that I would like to dedicate to my subwoofer, before mounting it in the car as always, I opened it and tested it on the bench.
The amp works perfectly, I decided to change all the electrolytics to give it a refresh and since I have a burson V5 classic I was thinking of replacing it with a signal opa.
In the preamp section there are 3 of them (2xjrc4568 and 1x5532), I also noticed in other amplifiers, that even adding only 1 burson (instead of the main opa) the performance improves, certainly lower than the original opa.
Has anyone already made these changes on this orion?

My beloved Marantz 1200 board was rebuilt, it blew an output and driver transistor, (one of the electrolytic caps was touching one of the pre driver transistors, grounding the circuit). After playing music through the amp for several hours, I noted that the rebuilt board heatsink is warmer than the other channel. Not hot, just warmer.

Output transistors were replaced with new MJ21193 and MJ21194 transistors. One driver transistor and two pre driver transistors were replaced, as well as an electrolytic cap. Reinstalled the board, bias and DC offset were set on both channels and both channels were stable after an hour. I'm going to clean and apply new heat transfer compound and mica insulators on the un-rebuilt channel tomorrow- or should I just let it be?

I was wondering if it is worthwhile to add a vacuum pump electric desoldering gun to my tools.I have of course been using the usual handheld pump but I was wondering how much more convenient would a gun be?
For example,is it going to desolder plated thru PCB/components that are very difficult to do?

Looking at Leader 152, HP 6205C, HP 6255A, Topward TPS4000, BK 1651, Heath IP-2718, and GW GPC-3020.

I have a nice BK1743 but now have a need for concurrent + and - and seems I can get one of these two channel units for less than I can get another BK 1743.

Any obvious winners or losers here?

Thanks for any advice on these or another affordable model I may have missed.
Budget is < $100 US and I don’t mind a bit of recapping or tinkering and don’t need lab grade performance.

Jeff

I want to start a project with a sealed 12" woofer. This is my first experience with sealed box.

Can you suggest a good software which correctly takes into account stuffing?

I have the impression that most calculators online do not consider stuffing properly, but I see that this is quite essential to get good results.

Currently have the Volt 2202/Morel Caw/538 ,MD32 tweeter in a passive cabinet .Driven by home built White noise 125 watt stereo amplifier.All vishay and high quality parts.
I would like to go active due to needing better quality louder sound in a much larger room.
Need help and advice as I have seen some half decent active crossover kit both 2 way and 3 way. K M Tech design Burnley UK.
I have enormous amounts of bits left over from previous projects including cabinets heatsinks etc the lot.
My source is now just a modified Denon 3910 player plus an unmodded version.
Passive all vishay Volume pot. (Passion?) All sacd/fi rez as I can still hear the difference.

My thinking was either Use a plate amp ready made for the Volt 2202
and the White noise for mids and also make/purchase a half decent amp for the tweeters.
Possibly 50ish plus watt for tweeters.
Alternative is build another.😱
Probably want to use the existing xover points 450 and 3500? However plate amps Ive seen usually adjustable only up to 200 hz point .
I gather that the Morel mid will go down that deep and is in enclosed portion of speaker cabinet.
Any suggestions thoughts (Volunteers?🙂😀)

thanks in advance 😕

Brand new blank board, never used. $30 plus a few dollars shipping. Half the price of new.

Send me a PM.

I would like to buy a PCB for my ANK 4.1 DIY DAC. So I am open to a PCB which fits with Audio Note Dac 4.1 or 5.

Thank you

I have a number of Focal 'K' drivers, they are mostly NOS I have not seen them for some time but think I have pairs of :-
5k413S
5k013L
6k412L
7k011DBL
10k515
I have at least pairs, and most are unused, I would suggest they are worth something as spares as the Aria kits etc from Zalytron and others used these drivers. I will dig them out if and when I get sufficient interest. Otherwise they will go on EBay at some point. PS. They all have Neoprene surrounds and last time I looked show no signs of age.
A good site for driver parameters is: Very old FOCAL Driver Datasheets - DIY-loudspeakers.com

Hi all,

My application is this: on my desk, source is computer, and speakers will be 2-3 feet away from me.

I was extremely tempted to go for the EL70 with dave's mMar-Kel70 to fulfil this application. But I've read great things about MA Alpairs, and I thought, why not step it up?

I'm deciding between the Alpair 6M or 6P in the mMar-Ken6 (http://www.frugal-phile.com/boxlib/P10free/mMar-Ken6-1v0-map-231009.pdf) or the Alpair 7.3 in the Slim Classic GR dMar-Ken7.3 (http://www.frugal-phile.com/boxlib/P10free/CGR-dMar-Ken73-301011.pdf).

From what I've read, the A7.3 is superior to the A6M/P, but I have a few concerns:

1. I know both drivers are good for nearfield (i.e. small room) setups. But at such 'extreme' nearfield range (2-3 feet), is there any significant difference between the A6 and A7.3? Mark specifically identified the A6M as suitable for desk-top usage (he said this in the spec sheet).

2. I intend to run the audio straight from my PC to the Lepai LP 2020A+. This is a less-than-ideal setup, and I do hope to upgrade. But the point is, I heard that the A7.3 is extremely revealing, whilst the A6 is more forgiving. Does this make the A6 more suitable for a budget-constrained audio enthusiast like myself? Or should I aim high with the A7.3 and gradually match the rest of my gear up to it?

Sorry for using such vague terms, I have not come to terms with most of the technicalities yet.

Are these just regular film caps or are they tantalum capacitors?

There’s no + sign on the cap

Hello everybody.
I´m new to this forum, I´m seeking some advice on repairing, if possible my old but loved Technics SC-CH700 system.
The problem is in the SU-CH700 Amplifier unit.
I´ts been working fine till it started cutting off on an certain volume level.
I searched the web and one of the solutions was soldering a 10nf ceramic capacitor on the pins of the fan socket.
I did that, when I plugged the system to AC, when I pressed the power button I saw the fan started imediately to work, I thought it was normal, but then when I chose the cd or the tuner there´s no sound from the speakers or the headphone, the only thing that I can hear from the speakers is a buzzing sound that seems ths sound of the fan motor.
I removed the capacitor, but the problem persisted.
I noticed that the IC LC7536 on the side board is getting to hot when I touch it, I dont know if its normal because I never touched it before.
What could it be?
Can someone help me? I have the service manual if needed.

Thank you all in advance,

Hugo do Carmo.

Wilbur, a ragdoll cat with learning difficulties will at some point, without doubt, attempt to lick the exposed valves. Playing this forward, that could be the end of wilbur. The wife would probably upsticks too. All of that is bad.

All jokes aside about the retarded cat..

Anyone know of either a diy solution that looks pretty (i dont want a mesh box over them), or a source of valve protectors.

One very annoying rule - I hate the look of the stacked rings you can get on fleabay / aliexpress.

On commercial offerings, i see glass tubes, they look nice, but i cant find any for sale.

ideas welcome.

I have an 80s guitar amp that I want to use as a doner for a fresh build. Basically the poweramp is a sealed unit and makes unpleasant distorted noises and the preamp is a little worse. The chassis, cab, speaker and reverb tank are all in good order.

And there's a power supply, obviously.

I was hoping to drop a simple chipamp in the place of the current power amp, and then front it with a nice preamp circuit, but the power supply is a lot beefier than I expected. It's labelled primary 22a 34v but my mains voltage is 240v, so I'm reading +-70v dc after the rectifier.

I've used an LM3886 in a project before, but the datasheet is quite clear that this voltage will melt it. Should I just swap the transformer, or is there a suitable chip I can throw in here?

hello,
i have order at diy store all what i could buy there to building the f6. i look at the guide 6l6 but for me isn't 100% what i should need for parts between toroid and power supply.

one guy from netherland wrote.
You need rectifiers between toroid and power supply, also simple protection circuit.
okay, but what is it excatly and where can i see it in the guide from 6L6?


Other problem is, my english isn't good enough to understand all 🙁



Thanks for our help.

Hi, I am looking for a new DAC and want to see if anyone would like to sell their project/setup. Ideally I would like to get a multibit DAC with a Tube output stage, but open to other suggestions so feel free to offer.

There is a TDA1541 kit for sale on the forum, but unfortunately it can only accept a SPDIF input, while I need also USB (which can also be the option to add a USB card which i can add myself).

I just picked up a pass kit in the swap meet a while ago and the toshiba jfets were included...

here are some pics.

the 2sk170 look normal but the other 2 have absolutely no writing on them. has anyone seen these?

Can I assume they are the j counterparts of the 170's?

are they real?

Apparently they came from someone named Spencer?

Thanks in advance!!

Hello all,

Here is my new little DIYproject, the "AT2380".

As many DIYers here, i often needed to attenuate a signal to fit better with the input level of the target system.
This is a tool that i need to perform some tests on my other design, the AA2380 ADC.

So, i was thinking to building an attenuator for a long time.
There is of course some already built, but good attenuators are generally dedicated for RF application with 50/75 Ohms impedance.
This is a too low impedance for the main audio and instrumentation applications that i target.

I work on this project for some months now, in parallel with some others.
I designed it to meet my needs and to be a cost effective solution to share it with all interested DIYers.


The main specifications of the attenuator are :

• full digital control (5M570 CPLD, VHDL coded).
• 2 pseudo isolated attenuators Channels
• Zin= 600 Ohms , Zout = ~ 0 to 300 Ohms (customizable)
• Flat frequency response (± 0,05dB) from at least DC..1MHz (± 3dB to 10 MHz).
• 0 to 127,5 dB attenuation in 0,5 dB step (8 bits / 256 steps)
• Direct dB attenuation setting displayed on 4 digits seven segments LEDs.
• Five selectable dB steps : 0.5 ,1 , 3, 6 and 10 dB by encoder increment.
• Optional output level auto-tracking mode from +10 dBV to – 85 dBV (attenuation only) .
• Full internal clock enable switch, for ultra quiet operation mode.
• Calibration mode for dBV measurement
• Relay fast refresh mode for audio volume control application
• Bluetooth UART link to control attenuator and measure output dBV level
• Shielded design to improve RF performance and noise immunity .
• Low cost design and easy to find parts.
• 100x160mm PCB size, fit in Hammond 1455 series extruded aluminum enclosure.
• Front and rear panel made in PCB will all holes drilled and with gold silkscreen.
• Through holes axial or SMD (1206) ladder attenuator resistors types.

These specs are preliminary as i don't have yet tested it, but it's the target.
Each attenuator channel use a ladder resistors design switched by 8 relays.
So, with 0.5dB resolution the attenuation can be controlled over 0 to -127.5 dB range.
(You can see how work a ladder log attenuator and calculate value here.)

The control of the attenuation is done by a rotary encoder with push button.
For easiest setting, the dB step by encoder increment can be choose between 0.5-1-3-6 or 10 dB.
The actual attenuation level is show on a 7 segments led display.

There is also the possibility to use it in tracking level mode.
When this mode is enabled, the output level of the attenuator track the desired level needed in the range of +10dBV to -90dBV (3Vrms to 30µVrms).

At this time, the prototype PCB has been send for manufacturing and i will have it in next week.
I will post a picture as soon it is in my hands.

You can show below the synoptic of the design :



Others infos will follow soon, and i hope that the project will interest others DIYers.
Regards.


Update of the 20/11/2017
------------------------------------

FInal V2.0 released
The full schematic and the manual of the attenuator is available below :

Full schematics : AT2380v2_sch.pdf

Operating manual and specifications : AT2380V1_Manual_v0.pdf

Functional Synoptic :
AT2380v2 functional synoptic

Complete BOM file for both track and not rack, with Mouser price list :
AT2380v2 full bill of material with Mouser price list


I finalize the Gerbers files, and the group-buy for bare PCB will be open on next week-end.
More infos soon. 🙂




Update of the 26/11/2017 -- PCB GroupBuy started
---------------------------------------------------------------------------

The PCB group buy is started and can be found here :
AT2380v2 2Ch Digitally controlled Stepped Attenuator




Update of the 30/01/2018 -- Firmware Update. (v0.23)
---------------------------------------------------------------------------

I released today the new 0.23 CPLD firmware that solve some bugs and add new features :
- Version display at startup
- Calibration mode.
- Relays fast mode operation (for audio volume control applications)
- Bluetooth UART mode attenuator control

Because of these many modifications, i have made a new design folder (v2.1),
provided to all PCB owners.

Some files are available to download on the links below :

AT2380_SynopticV2.1
AT2380v2.1_schematics
AT2380_Manualv1.1
AT2380V2_Bill_of_material_Rev1


Note that bare PCB are available, if interested send me a PM.


Frex

Hi, I have for sale 3x PAIRS of Tangband W6-1139sif in used but 100% working condition. Domestic HiFi use not thrashed in car audio!

£110 per pair including UK shipping. Happy to ship worldwide at cost.

Thanks for looking!

Hello, I have for sale a pair of SEAS 27TBFC/G metal dome tweeters.

These were purchased for a project but I have moved in a different direction so they were never used.

£75 inc. postage

Thanks for looking.

I have access to some Soundigital parts, mainly fets for the power supply and some for the class D section of the large amps such as 8K, 12K, 20K and 35K.
I can also flash the older 35K amps to with the latest hex.
Pm me for what you need.

I just bought a secondhand NAD preamp type 1240 (probably made around 1985-1990). I have no schematics and have a problem with the amp. The amp distorts prematurely and does not have enough gain/amplification. The problem is in the line-stage on all inputs and in both channels. First guess was that the power supply was not okay: but here I measure a nice plus/minus 20 Volts after rectification and including stabilization.

In the signal path there is an opamp type JRC 2043D around the tone controls and further there are a number of normal BC5xx small transistors. Maybe the opamp is the problem but why then should the problem be there in both channels? Not so likely. But if one of the small transistors is the problem, the same applies. Passive components? They look okay to me, no burnt resistors and the like, no loose solder joints.

Who has any idea what can be the cause of this problem?

Hello, I 'm looking for the Frugel-Horn XL plan and can't find a good link.

404 Error - Page Not Found doesn't work. Any idea ?
I've got a pair of lii-audio fast8. Here it is :

One Pair | New 8" Fullrange Drivers | Fine and clear sound | Fast-8 - Lii Audio, unique speaker, amplfier, quality and cost-saving parts for HiFi DIY

For sale this very nice turntable that I bought new quite some time ago, It has a free-standing motor.

Currently it has a Ortofon VirtusII cart installed.

PM me if there is any interest.

Beside the turntable there is a collection of about 10.000 LP's with pop, Jazz, folk and ~70% classical music.

I am selling SEAS Excel T25CF-002 (E0011) Millennium Tweeter with 15 hours of use so they are totally new.
The price is 330 € + shipping

I am making one amplifier for my headphones

Intention is to make a P3A with low voltage and high bias
willing to install this amp in the rack , run a cable for 2 ch next to my couch which is about 7-10 meters
then construct a local box with the plug a passive attenuator of 2W-5W in order to be able to control the volume localy

so in the output of the amplifier which originally is specified for 8 R and speakers i will feed :
--the 10 meter cable
--A set of resistors for headphone attenuation Expect 220R /2W in series and something may be in parallel ( advise needed )
--100 R 2-5 W potensiometer
--set of headphones 32 R

I was thinking may be a local Zobel

Do you expect an stability issues with that configuration ?
Is there anything else to treat my output with ?


thank you

Hi does anyone have any spare PCBs for the SSHV2 or 1 (salas high volt shunt), or complete modules for sale

I am uk based.

Thanks

Curious about this as it seems to me that delaying the tweeter output would be the same as setting the tweeter back on the baffle to preserve the time domain...but I'm not sure hence this question.

Thanks for any replies.

Does anyone have those 7" x 5" waveguides that Dave designed for the Transducer Lab tweeters? I would like to get a pair.

Hi Friends PCB Layout of tda2030/2050 Single supply amplifier.
Too late edit in picture, Use 680Ω resistance instead of 68Ω

Iʻm installing the electrolytic capacitors. The instructions call for 5 each 4700uF 16V. My kit came with 5 each 8200uF 16V. Is it ok to use these? Thanks!

I like the amp by solid tube, the D class don't have good sound field .
The is chip amp just the reference amp to my other type amp.

Hello , not sure if this is the spot to post or even the forum/wensite but here goes..
I have had nothing but great info and knowledge passed on to me from here. I was now wonedering if you could pass some more ?

Sooo if I were to take some detailed nudes of my preamp (magus mfa ) and post them with a parts and labour list buy of refresh and upgrade that are recomemded buy the creator of my pre (so tested and true ) would any one here be interested in helping me A-order the stuff to do it plus some new potentiometers that arent on the list B- take a screen shot of my pre and PS and circle what goes where , then send it back . I know. I know it should be easy .Im pretty good but have only did some small cap replacements What with all thats going on i didnt plan on doing it my self but...


I dont want this for free . Ill etransfer 1/2 up front . This kinda thing for the right person is 20 min . Please let me know your thoughts . Thanks every one
Ken

Hello,
Does anybody know what the laser head is in Nuprime CD T-8PRO Transport?
On official website they said Sony KHM 313 , but is not correct.
Thanks.

WTB: Servo Board with 6.8 version fro CD PRO-2.

Hey, Guys,

Doing a little closet cleaning and have a bunch of drivers to sell off:

4x AR 1210064-08 1" dome

1x AR 1-210155-2 5.25"

Pr. Audax AT170ZGP W08ZGP 6.5" treated paper, rubber surround

Pr. Audax HT110G0 5" treated paper, rubber

1x Audax TW037Y0 dome mid

1x NHT 1-11-043-1 6.5"

1x NHT 11-001-03 4.5"

Pr. NHT 1" dome, shielded

Pr. Nokia 4" paper, shielded

Pr. Peerless 1" domes, shielded

Pr. 1" domes "Star Trek / Ouija board" faceplate

1x Polydax 4" paper, shielded

Pr. Polydax HIF17JVX2CA12 6.5"

Pr. Seas D20TD-05 3/4" domes

Pr. Tonegen 8", poly, rubber

4x Tonegen 4", treated paper, in enclosures

Pr. Tonegen .75" dome

Pr. Vifa 6.5" molded plastic frames

Pr. Vifa 6.5" molded plastic frames, bucking magnets

Pr. Vifa 6.5" molded plastic frames, shield cans

Pr. Vifa TC26SF05-06 1" dome

Pr. Vifa 3.5" poly, rubber

No- name 12", heavy steel frame, bunch of other stuff, just tired of writing. Might be a little off on some of the details, but you get the gist. I'd like to get $200 for the lot. Available for pickup in Richmond, CA most weekends. For $100 more, I'll through in a bunch of 6.5" and 8" woofers.

Anyone want to pick them up?

hey all,



been searching for a few days on this topic, nothing totally dedicated that i can find so apologies if this has been discussed else where at length


have (2) L20.5 amp modules, and (2) SMPS to power them. is there a required distance they should be away from one another in the same enclosure? the amp modules will be mounted vertically on the enclosure's side heat sinks, while the SMPS will be mounted horizontally (so perpendicular to one another) and the space is somewhat tight, probably 2 or so inches from one another. will this be problematic?

Helo,guys !

Do anybody has diagram for Magnum-sa12 professional amplifier - SENIA Music echivalent 1200 MachAudio - MJL 1302A / MJL3281A

Thks in advance

In "6 - 24 crossover" thread there was some time ago a short discussion about the quality of WIMA capacitors. Also a little about the "mysterious" about the "Black box WIMA's". I decided to ask about them and also which WIMA type to select today for audio. After a couple of mails and some waiting I got this information. It is information only.....I don't sell WIMA's 🙂

********************
The BlackBox was a special edition that we developed in early 2000.

With this special edition, the goal was not to be pricely competitive against our competitors. The goal was to deliver the best sound experience.

After several research and testing, we concluded that the use of a thicker dielectric drastically minimizes vibrations inside the capacitor, which has a positive effect on the sound quality.

We used a polypropylene dielectric with a polyester foil metallized with aluminum. This dielectric was thicker and as you can see very clearly the BlackBox edition has physically larger dimensions than the standard capacitors.

When the dielectric is thicker and you need more raw material for the caps and potting, the capacitors have a higher manufacturing cost and value.

The BlackBox standard alternative today will be direction MKP10. However, it is very important if you want extreme sound quality and if there is enough space available, that you consider a higher dielectric strength and higher nominal voltage due to the film thickness: The higher the nominal voltage, the thicker the foil.

What was then a BlackBox 250 VDC ... today should be something like the MKP10 series in 400 VDC, because of the thicker foil.

Example:

MKP 10, 400 VDC, 0.33 µF 20% = BlackBox 250 VDC, 0.33 µF 20%.

Nevertheless, the 250 VDC´s capacitors are also very optimal and beloved for sound engineering. This is because of the high quality of WIMA capacitors.

Most of our audio customers today also prefer a capacitor with a lower tolerance: 5%. Somehow this lower tolerance also has a positive effect on the quality of the sound.

I hope I could help you guys a bit further.

Stay safe and healthy.

***********************

Only just picked this up cheap.


It gets stuck at start up saying "initialising" and that is it, hard drive sound happens and CD drive, but does nothing else at all.


It has a ram module in it, could that be bad? Or hard drive? I took the HD out but it was still stuck on start up, tis driving me mad!!! Does anyone know what type of RAM it uses?





Any help would be appreciated

This is my first start to finish speaker build and I have some questions I was hoping you guys could answer. I have built one pair of speakers before, a DIYSoundGroup pair of Apollo 7 TMs. I was really happy with them as a stereo system and now I want to put together a 3.1 system. I am constrained a little bit with height, as TV mount height limits me to 5” of clearance.

The 5” clearance is where the need to build comes into play. I was shopping around for center channel, but i wasn’t excited about the ones I found that would fit.

At first I was thinking of a MTM in a vented box, but then I got to thinking about a MMTMM in a 2.5 way configuration. I’ve been toiling around with WinISD and XSim, but am not exactly 100% confident about what I’m doing.

For the box I plan to use 1/2" MDF instead of the usual 3/4, in order to save space. I've played around with a small one and a larger one, but in it's current design I am thinking of two separate chambers instead of one big one. Each having a vent off to the side. Does this serve an advantage over one large box? With the current tuning I should get an F3 of 77.5, which should be fine.

For driver selection, I figured it would make sense to use a tweeter that is the same as my other speakers to match, the Wavecor TW030WA11. It happens that the Wavecor makes a pretty good looking driver that fits the bill. I've also looked at some Daytons, a Tang and one from Scan Speak.

Tweeter: TW030WA11

Wavecor TW030WA11 30mm Semi Horn Loaded Textile Dome Tweeter with Rear Chamber 4 Ohm


Woofer: WF120BD03
Wavecor WF120BD03 4-3/4" Balanced Drive Paper Cone Mid-Woofer 4 Ohm


I think I should keep it 4 ohm to match my Apollo MT's. Does this make sense?

Do I base my voltage on Denon’s states specs of 75w into 8 ohms stereo? Does a home theater receiver’s power change when driving 2, 3, and 5 channels?

How much should I be concerned with baffle step here?

Given that this is a MMTMM center, do I need to only look at "Midrange" speakers vs Woofers? I understand that these differ, but for this application which way should I lean?


After reading a good amount of reading, I'm looking at 2.5 way instead of a 2 way. It seems a bit more complicated, but not too crazy. It looks like if I wire the mids in parallel-series I can keep the ohms at 4.


Thanks in advance for any advice! This is still the first real draft and some of the dimensions are still in play. Also, I'm a noob here obviously, and there will probably be some very obviously problems here that I am not seeing. Cheers!

Looking for spare 1uf and 10uf, 1 pair each, 160V+
Auricap XO
Claritycap CMR
Jantzen Superior Z-cap

Ship to Canada

Looking for spare 1uf and 10uf, 1 pair each, 160V+
Auricap XO
Claritycap CMR
Jantzen Superior Z-cap

Hello,

Some time ago I wanted to rebuild a pair of old speakers, and I got a lot of great advice, but I just did not have time to get into it until now. I have already been given many tips about kits being better for newbies to learn, I have embraced this and I already have a couple in mind for another future build 😀

So I have changed my mind on what type of approach I want to try for these old speakers, so instead of “reviving” that old thread I figured I rather make a new one because I would like instead some feedback, tips and opinions on weather to fix or repurpose these speakers which sound quite good and I would very much appreciate your input to weigh my options!

Disclaimer: I am still relatively new in this realm so for the moment I am not savvy enough to be up to the task of designing and making a crossover from scratch and creating a whole speaker from scratch, nor heavily investing in the repair/repurpose. This is more of a simplified rescue to get into experimenting with speakers and box building. So cost and simplicity are the most important parameters for me for this one 🙂

Speakers (pictures attached) : they are an old pair of 3-way Sanyo SS-60 speakers.
I don’t have any detailed specs to them except for the ones below and on the speaker themselves (I know it's nowhere near enough info for complex approached but it is what I have found for these oldies):
Power-> 60/120watt
Freq. Resp.-> 30-20000Hz (cant find +-db anywhere)
Impedance-> 8ohm
Highs-> 5cm
Mids-> 6cm
Woofer-> 18cm

“Plan” A - Fixing: Just redo the box respecting internal dimensions and reusing original vent for the sake of the woofer (I don’t yet want to get too deep into measuring parameters, this will be something for another project), keeping electronic components as is as much as possible. I will check these days if the smaller speakers are worth fixing (small tear on the surrounds and sometimes a high and a mid wont sound). If the smaller speakers don’t work then I won't try this approach as I assume I will have to start matching speakers and designing Crossover, etc.

For this Plan-A my main doubt is regarding the crossover. These 3-ways don’t have a “normal” crossover (at least not like the ones I have seen online on a nice neat plate). It seems that there are resistors, capacitors, etc, stuck directly to the wiring that is connected between speakers. (pictures attached of the back part of each speaker)
-Is this like an “old” way of doing it?
-And would it be a good idea to simply replace all of these “crossover” components for new ones and re-hook it up following that same “old” way? Or is there a better way to rebuild the crossover following the “old” way (like using the same type of components on a plate)? Any tips/corrections/resources to how to do so are very welcome.

“Plan” B - Repurpose: Assuming all speakers work.. Dismantle the speakers, and make different “types” of speakers for a small DIY 5.1 setup (actually “4.1” since I don’t have a center speaker yet). So in short I was thinking of making 2 subs out of the 2 woofers by making 2 boxes and adding amps to each. Then take the high/mids speakers and put them in small boxes to make the satellite/rear speakers of the "4.1".
(They would be used with an old Yamaha RX-V430RDS, which has a fixed cutoff at 90Hz for the sub, and has 1 sub pre-out.)

These ported woofers seem to have quite a good lower end judging mainly by how deep and good they sound with various types of sub-heavy music hence why I wanted to attempt this. My reasoning (if any lol) with the “4.1” set up is to mainly skip the tampering with designing a whole new crossover for now which is a bit overwhelming for me at the moment as I am starting my learning with that.. so..

a) I am assuming that small rear speakers don’t have/need crossovers, and to be honest it has been challenging to google if I need a crossover for small rear speakers for surround sound.. from what I have read it seems that unless I want a high end surround speaker I don’t really need a crossover for the surrounds.. am I wrong?

b) Also I am assuming that adding an amp to the woofer to make an active sub seems** like a simpler undertaking compared to the crossover.. am I also wrong?

c) So for the DIY sub, is it as simple as redoing the current box (keeping internal volume and port) and adding an amp matching the power rating and ohms of the woofer? Is this ok or does the box design game change completely once it is a powered woofer? If so, I would appreciate tips and some good resources for me to read up on.

d) For the sub amps, would an external amp to which I would connect both woofers be a better option/have an advantage as opposed to separate plate amps? Would having an external amp save me the redesign of a box and allow me to just recreate the current box and connect? Again, any tips & resources on how to match either the internal or external amp is appreciated.

As I mentioned this is a newbie experiment/rescue, so measuring and interpreting parameters and crossover designing is for now a bit out of my league (at least I think so, if some things are doable please correct and teach me) 😉

I really appreciate any advice, recommendations and critiques to both “plans” so I can weigh my options

Thanks!!

Hello,

This is my first post here. Hopefully, I've posted in the correct forum.


I'm salvaging a polk subwoofer with a blown amp by trying to convert it to a passive sub.

I have a crossover out of a Bose Acoustimass 5 series ii subwoofer.

The crossover has inputs and outputs for both right and left since the bose sub had two drivers.

The Polk sub has one driver.

Should I connect both the right and left outputs of the crossover to the one driver?

Thank you for looking!

I'm looking for a 15" woofer for a new pair of speakers. I want an F3 of 30 Hz (built), better yet, 25 Hz, "probably" in a vented box, but sealed is fine, too. Crossover at about 150 Hz or less to the upper bass driver. I would like to have a box of less than or equal to about eight cubic feet (<= 8 C.F.) (about 2' x 2' x2'). One woofer left and one right - not a single, and not "multiple".

I'm aware of JBL 2226 - doesn't go low enough. Aware of Dayton 15" - not available. Eminence - I haven't seen "the one".

Anyone have another idea?

To review:

15", F3 at <= 30 Hz (built), ~ max cabinet 8 C.F.

Thank you!

Greetings!


Do any of you know a loudness control circuit, that i could add to any line

level signal and so that the amount of "Loudness" can be varried?


I would like a circuit to expreiment on 🙂


Thanks in advance to all of you geniuses!

if i upgrade my caps to a better quality will it make a change to sound i hear

Hi,

I'm new here, but the moment I saw the baking tray amplifier on the gallery I knew I was in the right place.

I'm putting together a home cinema system and fancy building the power amplifier myself. I've done plenty of electronics projects in the past and have been looking at my options.

The two basic ideas I have are:

1. Buy 7 replica Quad 405 boards for about $30 each which are about 100W RMS into 4 ohms.

or

2. Buy 7 class-D amps aiming for about 300W RMS each.

As a person who has studied power electronics I understand the technical differences. I also don't want to open up a long debate about how good different class D amps sound.

Given that the Quad circuit is well and truly tried and tested and can be had for less than $40, is there any real point in going down the class-D route?

FYI the surround system will be based on six ATCs SCM7s and one ATC C1CA, probably driven by an Arcam AVR of some sort.

Thanks in advance for your advice.

Hi guys

I have been playing with full range drivers for a while. My current favorite is my Fostex FE126 Planet10 modified unit, in a double folded horn. I also have a pair of Fostex 8" Fe 206 that i have tried in various configs, but have not been totally satisfied. I have been thinking of using them in something like the "Kleinhorn" or "Sato" for the longest time, but am put off by their massive footprint, until I came across the AER Aerofon. Much smaller footprint, and similar concept. I see that they spec theirs down to 35Hz. I do understand that this is driver dependant, but would like to try this design for my Fostex 8". Anyone have any plans for a horn of this type and size?

Reposted

Reposted in the amp section.

Update: “Sold” to the lowest bidders




Found these in the bottom of a box, they were given to me back in 2005 and have traveled the world as I moved around (not that that adds any value but just shows I should have admitted I had no interest in them years prior)

Free to good or bad home with preference going to the easiest shipping (that means USA folks, but if no takers I’ll upgrade to an international stamp and hope for the best). If you care about them securely arriving at least show me you have or tell me you will make a donation to the forum and I’ll pay for proper shipping.

PM or post up to you, and please tell me if you want all four as most would only ever use two of them so I will assume you want two in the absence of clarification.

P.S. This design uses some unobtainium critters, please don’t ask me for further details as it’s all at your fingertips.

Hi guys..

I just want to share my experience with Audionote copper mylar in oil caps.

I built 300B SE amp base on Audionote Quest but modificated to stereo amp instead of monoblok amp. I used Audionote caps 0.33 uF/630v copper mylar in oil (copper tube, black label not white and diameter bigger than current Audionote caps). I bought 1 pair from Partsconnexion Canada (they are a nice seller doh) about 1 years ago and just 6 months ago I finished the project and started to fire up the amp and sounds very lovely.

2 days ago I turned the amp and playing some vocal music, everything seems going ok until 2 hours during playing some slow music sudently I heard very bad distortion on my left loudspeaker and the volume seems decrease. I smelled bit burnt odour near the cathode resistor (it's very hot on that resistor). I hurry up turn off the amp, get my multimeter and checked everything until I found that the Audionote coupling cap was shorted and pass through 271vDC!!

Maybe you guys ever have experienced fail caps as I did? I've sent complaint to Audionote contact via email and haven't any reply until 2 days maybe they too busy 🙁
I questioned them about the quality control and cap durability or maybe I just unlucky hehe.....I never experience any problem with other cap I use until now (I also use Jensen copper in oil, Mundorf Silver Oil, Supreme, Dynamicaps, Jantzen Silver, etc)

For now I doubt to use Audionote cap again, maybe I will try Jensen paper tube instead buy again AN caps

cheers....
Erik

Am servicing a Dean Markley T60. The HV secondary went shorted and there's a considerable amount of rust on the transformers.

Does anyone know where I can find a replacement for this transformer?

Also, does anyone have schematics with the transformer ratings? The links I've found in past forum discussions are all dead now.

I've built several kind of amps, from fully symmetrical design to single differential design. All have turn on and turn off thump.
Searching here, the most encouraged cure is to use output relays.
But some good commercial amps do not have these thumps, although they do not use delay relay at all.
1. What is the mechanism of this Thump generation?
2. Is there any trick if we design an amp so it will not have thump?

I am considering the idea of using digital correction for room and speaker correction.
However i use vinyl as a source and a tube amplifier (amongst other things)
Is there a high quality and inexpensive way to do this or is this simply incompatible.
I am not really sure where the thread belongs but would be very interested to have some input.
Thanks
Mike