Hey all!

I'm beginner with vacuum tubes and recently decided to build amplifier for PC speakers. On russian forums found simple schematic of single-ended amplifier with 6N3P (6H3P) and 6P14P tubes. I had all components and started to build it.
Components I have - 6N3P-EV, Tesla 6CC42, 6P14P and Tesla EL84 tubes, TVZ-1-9 (4,5kOhm, commonly used in soviet (russian) amps with 6P14P), cheap chinese no-name (5k Ohm 5W) output transformers and TS-180-2 power transformer from old tv.
After tests with chinese output transformers got -3dB at 70Hz and 2W. So decided to use TVZ-1-9 and got -3dB at 20Hz and 2W. Last one definitely sounds much better.

The measured voltage are a bit differ from original schematic:
- 6CC42 pin 4 120V,
- 6CC42 pin 2 - 1,5~1,43V,
- EL84 pin 7 - 247V,
- EL84 pin 9 - 6,2~6,7V,
- voltage drop over OT - 14V.

Anyway it all seems work stable, I already using this amp everyday for a month and very satisfied with sound compared to TDA2030A amplifier, that was built into PC speakers.

Yesterday I got idea to update my guitar amp, that built with TDA2030A too and sounds terrible.
I found few schematics with EL84 tubes and noticed that screen grid connected to HT with some resistor and in schematic I used earlier have it connected directly to HT. So in result I getting +263VDC at screen grid while ~ +250VDC at anode plate. After tiny research over forums and articles (most clearly described here The Valve Wizard -Single Ended) I found that screen voltage must be equal to anode voltage or bit lower.

And now I confused.
Is the original schematic have mistake there? Does screen grid must be connected after R8 (at my schematic) in series with 1k resistor?
Thanks

Sony PS-X9 - replace varactor VD1221?

There are quite a few VD1221 varactors in my Sony PS-X9 turntable. They have a bad reputation and I was wondering if I should replace them with two diodes in series or with NOS VD1221s which I have. Could I even use the two diodes trick to replace them in every position/ situation? (Varactors must be around for a reason 😕)

any one here work on one of these before ?
i just need to know the resistor next to the x2 rated cap on the front panel board , what it job in the front panel circuit ? mine is just smoked , but i need to find out what cause it to overheat .
attathed is the pictures of the board and resistor in question.
thanks
Peter

This oldie had all low value electrolytics faulty. One channel has very low distorted output. +12v missing. Anyone with circuit diagram?

Hi,

I restor a Yamaha A760 amplifier.
I've replace the filter capacitors, original are 2 x 6800uF 63V (Replaced with 2 x 10000uF 63V)

Replace old RIFA X2 type Oil Capacitor (0.47uF 250v).
This one :


>>Service Manual here<<

But, i've a noise on my test speakers (Around 50Hz) amplitude of the noise depend of the volume control.

And ... 90V between Chassis & Earth !!! 😱

Some test on the amplifier ...



I've the same issue before change filter caps & X2 Caps ... are you any idea ?

Add a power cord with earth ?..

Thank You Community !

I'm looking for advice on the best (sonically) way to add a balance control to my type 26 (or the 01A) pre. My room has an imbalance, no matter what amp or speakers I use, so I need to balance the pre. The speakers can't be moved, nor the room altered, so this is only reasonable way forward. As both pre-amps have two central knobs on the front (volume and source) a pair of small knobs, one each side, would work best visually. 100k TKD pot on the 26, 100k PEC on the 01A. I've seen the John Broskie design; is that an acceptable method? One switch each side. Depending on the quality of the components of course.They're Here & More Sonic Control

Hi all

After watch one of Mr Carlsons YouTube videos were he introduced his Signature Tracer , and it got me thinking I might find one useful but a quick search on the interweb got me a little confused (easy to do these days) so a few of questions

Is a Signature Tracer the same as a Curve Tracer.

Anyone got a usable schematic for a DIY option.

Are they as useful as they appear in the Videos.

Here is the Video, obviously his is is built into a modified scope chassis but they can be built as a standalone unit to work with a scope set to XY mode

YouTube

Thanks for any help or input on this.

Paul

this circuit seems ok until the output reaches around 14v peak to peak, then i get an overshoot on the rising edge top only.


below 14vpp, the 47p miller gives a nice square with slightly rolled off corners, input signal is 10khz square.


any ideas? the ltpsice sims do not show this behaviour.

I am looking to put together a pair of subs. Not sure whether they will have a plate amp on each one, or a stereo professional amp driving the pair. For this thread it really doesn't matter.

I like the concept of auto calibration. PE has a couple of sub plate amps with this capability built in. MiniDSP can do similar things. I would prefer a less costly approach using something like a Behringer (or other inexpensive pro) Amp with something as a front end. What are my choices?

One note, PE has a little inexpensive box which can do auto calibration from an Apple device. I do not do Apple, and will never do Apple. Android, Windows, even Linux if I need to, but I will not bring an Apple device into my home.

I use REW (not to its fullest) so I have a calibrated microphone and a computer to do the analysis. Are there any inexpensive amps (Pro or Plate) with either DSP or parametric equalization built in that REW can upload calibration info to using USB?

Other ideas?

My thoughts are a pair of Ultimax 15" or 18" drivers or similar in sealed cabinets. Maybe 4 drivers if I go 15". So I will want a fair amount of power.

Hi

I was looking to build some LxMini speakers and might do it, thought may as well check if anyone has some they were looking to sell first.

I live in SF, and visit Sacramento often too.

Thanks

S

521.4 I really like the sound, however my space is a bit small, so wouldn't build it, and if it doesnt work plan is if I buy it to use the mid/hi and sell the woofers (mabye build the Davey sub for the bass)

I apologize ahead of time if this question has been answered multiple times, but I couldn't find it. I am putting together a sound system on the cheap in my basement with discarded but still functional components - desktop computer with HDMI output, 55" TV, spare amps and speakers. I'm thinking I could buy a sound card (external or internal) that supports 7.1 or 5.1 / Dolby II, and directly drive my amps to watch/listen to online stuff like Netflix, Spotify, Youtube, etc. So the question is, do those sound cards support setting large/small speakers, distances, levels, etc., like receivers do? Or do I still need a receiver to properly set up a surround system? I have perused the specs of various sound cards but they don't seem to go into that type of detail. Thanks.

Good Morning Folks,

Many of you have noticed that we have introduced a new release for Trident. It is Version 3. Naturally that has generated a lot of discussion. I have been wanting to present the changes and answer the questions, so lets do it.

First where is version 2? Version 2 exists, and it is also very awesome, but it is also *very* expensive, and Brian and I decided is was probably not practical to pursue because of the very high parts costs involved. In the end we found away to get the performance gains without the degree of added expense. Version 2 had slightly a more accurate voltage reference, but Version 3 actually has lower noise. So in the end we decided to simply go with version 3.

Why the version 3 update? Version 1 works quite well, and people really enjoy it. Both of these things are true. Why touch it? But as is the case with many things, the uses for Trident necessitated a redesign. Since I needed to change Trident to support new applications (Opus and others) I took the opportunity to apply feedback to make it better.

Trident version 3 is a product of several things:

• We really needed a higher voltage (5V) output version for Opus
• We saw many people were forgetting to install R4 so we wanted to facilitate pre-installing R4. So now there are dual pads SMT and TH.
• We wanted a more robust Trident that can stand a higher voltage drop
• We wanted better bandwidth and better stability in high EMI environments and into very dynamic loads.
• I just couldn't leave it alone. 🙂

A couple of features of the new version include:

• A better error amp
• A better local feedback scheme at the shunt.
• A better layout with a spot for SMT CCS resistor - R4.
• Some other very small circuit tweaks(I won't give all these away).
• Much more robust transistors. They will very easily handle any TPA app.

People are always asking me if it is a significant update. Well yes in many ways it is, but that does not mean I believe everyone should rush out and swap tridents for the new version. If you are happy with your current setup then you don't *need* to update it.

Owners of the previous Trident can upgrade the error amp if they have the ability, but that will not make the two versions equivalent. There are several other changes as well. If you wanted to upgrade the error amp on the Trident you have many choices. I would suggest OPA209 and OPA211 as they are both known to work quite well.

I owe a lot of thanks to a couple of skilled engineers (with far better testing gear than I have) who helped me in critically analyzing the Trident. They know who they are, and I hope they know how much I appreciate their support. I am not sure I should name them, because some of the help came from people who may wish to be anonymous. I would feel badly if I didn't at least give credit where credit is due. So thank you. I have often said that we have the best community of DIY folks a person could ask for.

So if the question is (And I get this very often) - "Russ, would you personally upgrade?" My answer is very simple. Yes I certainly would. The answer is the same for Buffalo II or Buffalo III. So now that is out of the way. 🙂

For those of you getting Trident V3 configured for Buffalo II/III notice that R4 is already installed! Do not add another one!!! 😀 Trident 3 will also be available with no R4 installed so that you can configure the CCS current yourself - but that edition is not available yet.

I hope that answers most of your questions, if you have more then please ask.

Cheers!
Russ

I need to get 7.1 audio into an x86 machine. For the sake of example I'll assume the source is a PS4; I want a fairly generic approach that could work with any 7.1 source with little per-device hassle.

Approaches I have considered:
* TOSLINK with Dolby Digital Live/DTS-I: This is probably the path of least resistance, but it can only handle 6 channels, it's compressed, and it has a serious and unavoidable algorithmic delay. Additionally not all devices that have a TOSLINK port can actually do realtime Dolby (the PS4 can, many desktops can't without hacked/unofficial drivers).

* Analogue: The PS4 doesn't have any analogue out, but inexpensive "7.1 sound card" devices are available which will happily produce 8 analogue channels. I could buy a fairly expensive professional USB audio interface for the macbook, lead 8 cables across, deal with levels/clipping/interference/all the other issues that come with the analogue hole, and hopefully get an acceptable result.

* USB: This is the idea I like the most, but I'm not sure if it's practical. Imagine a box with two USB A cables coming from it. One connects to a source, which sees a 7.1 UAC1/UAC2 sound output. The other connects to my macbook. Ideally, it shows up as an 8-channel UAC1/2 input device. Less ideally, but still workable, it could just show up as some kind of high speed serial stream of bytes to be dealt with in software.

Please enjoy the world's most detailed and informative diagram:



This would allow me to just plug it into any device that can output 7.1 over USB and enjoy 8 uncompressed low-latency channels.

I imagine this is going to involve finding a combination of ICs to do the job and composing them appropriately, perhaps writing some code for a microcontroller somewhere. It might be entirely impractical, in fact.

As I'm sure you can tell, I'm not an electrical engineer and am very much out of my depth. But I'm a quick learner, and if anyone can point me in the right direction, I'm perfectly willing to break stuff and waste plenty of time and money on this.

Hi all.
First post so be gentle.

I'm in the process of renovating some newly aquired B&W DM2, Series 2's and I'm finding getting matching electrical components a real pain in the backside.

Now please consider I'm almost a total newby in the world of audio electronics and have only a basic knowledge at best (we all have to start somewhere eh) so i'll probably end up asking some dumb/obvious questions...bare with me. 😉

Firstly I'm lead to believe that installing a higher voltage capacitor onto a crossover isn't a problem...but how high is it realistic to go? Could iI replace a 25vdc Cap with say a 250vdc cap? This is just a rhetorical question .
The same question regards Capacitance....could i replace say 75uf cap with an 80 or 90uf cap? I understand there will be tonal differences replacing caps with differing Capacitance ratings, so with that in mind i am wanting to keep the sound as close to original spec as possible and to achieve this how much would i be able to adjust the Capacitance rating by? Please stay with me on this.

I've put up a couple of pictures and was wondering whether someone could guide me on suitable replacements for the 5 Grey Resistors? The measurements on the side say:

No1(X2) = FA78 Ω (has a "W" in the omega symbol) 10R 5%
No2 = FA78 Ω ( ) 2R0 5%
No3 = FA78 Ω ( ) 6R8 5%
No4 = FA78 Ω ( ) 8R0 5%


Thank you in advance for any guidance.

For Sale Cirrus Logic New old stock factory DAC eval board new in the box.

• CS4398 chipset
• XLR balanced & SE RCA outputs
• CD eval software
• Serial cable
• TOS, Spdif, and Direct PCM & DSD inputs

Uses +5, +-12 VDC

$95 plus actual ship cost by your desired method. Will ship to Canada, Western Europe, USA. Local pick-up in Silicon Valley can be arranged.

-David

Hi,

My source is an Onkyo C-N7050. The left side now is a lot more powerful than the right.
I checked everything, no doubt it is the culprit.
I run it trough a passive reducer Shiit Sys and a First F5 I built last year.

Beside sending it back for repair, this confinement is no help, any idea I could solve this ?

small speakers or mini monitors are said to have better soundstaging then bigger speakers, is that due to the small baffle size or is it due to the small driver used ?

in my tests, by keeping the baffle size constant and changing driver size (midwoofer) suggests that driver size is the key and not the baffle size

what is your experience?

I am working on adding a DC supply to an existing AC circuit.

At first blush, a simple bridge of 4 Schottky diodes and a large filter cap will do the trick, maximizing the rectified DC voltage.

Thinking about it some more, I am worried about the effect of rectification spikes on the AC loop, as there is a component there that might be sensitive to spikes.

I would say as a design criteria minimizing rectification spikes on the AC side would be highest priority, with maximizing DC voltage next priority.

Would someone be so kind as to walk me through what basic additional elements would achieve this? For example, diode type, snubber capacitors, inductors, etc. Not wanting a walkthrough of a scope trace, more like a 1st principles, belt and suspenders answer.

Hey folks, we're currently in the process of designing a multi channel DAC centered around the ES9038Q2M in mono mode. The DAC will feature a motherboard with PCI express connectors, i2s-, i2c- and differential master-clock-distribution. The DAC boards themselves will be all mono channels with opto isolated i2s and i2c lines, diff-to-single-ended clock receiver, I/V and relay based volume control with 64 1dB steps. But i digress, that will be a topic for it's own thread once all the schematics and layouts are done.

Anyway, on the DAC boards we decided to use OpAmps as voltage regulators for the analog circuitry. Why you ask? Well, what comprises a good voltage regulator? It should have:

- high PSRR
- low output impedance
- high open loop gain for the feedback to work
- it should behave symmetrically on load steps, be they more or less current being demanded
- also THD seems to matter

In my opinion good OpAmps should tick all of the above boxes. So, on to the actual implementation. I have attached a part of the schemtaic, the AVCC PSU. We will use the OPA1622 because of its low output impedance compared to other devices in the same family. The output stage being symmetric should help with both symmetric behaviour on load changes and it should also halve the output impedance vs. just one pass/shunt transistor.

What will have to be determined is if the ferrite bead in the AVCC output line can stay, it will probably have to be replaced by a 0 ohm resistor simply because the lowest impedance beads have a too high impedance even at audio frequencies.

What I'm wondering about is the usage of a snubber at the output of the opamp. The output of the opamp behaves as an inductance at higher frequencies which will produce overshoot and ringing in the small signal step response. So i thought the a snubber there would be beneficial. From a paper by TI i got that the snubber capacitance should roughly be three times the "parasitic" capacitance, which in this consists of 2x10u + 2x4u7, so i chose it to be 100u. The resistor value is calculated as sqrt(L/C) (it's saying 1R for the moment, please ignore the actual value for now). So the big question is how to find out the output inductance of the opamp.

I have a theory as to how to calculate that but I'm not 100% sure. Maybe somebody can shine some light on that. Also I'm looking forward to your opinion if that snubber makes any sense at all in this position.

Looking forward to your answers and stay healthy!

I have been collecting boat anchors for years, I think that I have met my match. Probably because no tubes are used.
Following the Section V Adjustments, I found the following:
1. Volt meter adjustments-no problems.
2. Gain adjustments-no problems.
3. Oscillator adjustments-no problems.
4. Analyzer adjustment- could not get the distortion range past 50dB without the meter hard pinning to full scale.
I then tried a sine wave with a known distortion, the 339a worked perfectly.
It was accurate in the 80dB range. I measured the 339a oscillator (with another analyzer) it was better than 80dB.

Conclusion, the instrument works great when not using the internal oscillator.
Any ideas would be appreciated, thank you.

i have for sale a raspberry pi 3 b+ used a few times but like new.
i prefer shipping in europe.
price: 29.50 € included shipping in europe.

I have a pcb for the attached schematic. Right from the output of the 6x4 regulator, the silkscreen on top of the pcb shows a 20 ohm resistor and the bottom shows a silkscreened choke (no value). Pics online show the resistor. Neither are on the schematic. I have built 6 tube supplies, all with chokes, all cap input. The pads here would make this choke input. I plan on using the choke, not the resistor, for choke input to load. Then there is the rest of the supply. Let’s come back to that.

SO, to find the correct choke using the tube data sheet for a choke input supply, here are my calculations for a 6x4 tube. I have never used this before but shows little sag at any permissible voltage:

Transformer that I have is 600v center tapped

Vload=270
Iload=15ma x 4tubes=60ma
Vmains=120
Fmains=60hz

Avg current per plate- Iplate= Iload/2= 60/2= 30 ma
Peak current per plate- 4Iplate= 4x30=120ma
*max plate current for this tube is 220 per plate

Peak inverse voltage
v=(1+rt2)vload
v=2.41*270
v=650v
*max inverse voltage for this tube is 1250v

Here is where things get sketchy for me. How do I interpret the x axis on the graph, which is labeled “dc load milliamperes”? Is this average, average per plate or load current?

At the bottom, it shows typical operation for 400volts input @ 70mv load requires a 10 hry choke. I can’t reconcile that against the chart.


I have no idea what size these files will end up as so let me know if there is an issue. Thanks.

I don't have an oscilloscope. Is it accurate to some degree to crank up the input level of a sine wave until the amplifier clip light comes on?

i am trying to clean out some of my projects that never managed to make the cut for getting done. More pictures are available of each item and price does not include shipping/paypal fees, those will just reflect actual prices.
.
Dahlquist low pass stereo xover, DQ-LP1 - top is a little scratched up, i picked up used and never got to this, so have never used this. Looks original inside. SOLD
.
Hubbell hospital grade plugs for DIY power cords, these are new, in box, for 20amp plugs, so one of the prongs is not parallel to the others, so you must have a 20 amp outlet to use these. $10 each, 5 available
.
Audiosector DAC, RCA outputs, not sure what the input plug is called, but i have a converter to make it an RCA input. I have used this, my cord eventually stopped working. No power cord or other cables supplied, some rust on the transformer. $150
.
Triad S-77U transformer, big heavy, I am not sure what they are for, outputs or some sort line tranny. Used, with fairly short leads, but workable. See attached for catalog page. $15 each, 2 available.
.
Also a knight KS-10 multiplex adapter, tube unit for converting mono radio to stereo, has been recapped, 10-15 years ago and did work, haven't touched in quite a while. SOLD

Happy to supply more photos.

Is it supposed to work?

Small class D amplifier driving an AB2 805 PP through a 1:12 transformer.

500V 50mA on each 805 (internal resistance about 13K), max g1 swing about 170Vpp for 35W output on 8K load, max Ig1 about 45mA per 805.

OPT: TTG-CFB8000PP - Tube output CFB transformer [8kOhm] Cathode Feedback Push-pull - Shop Toroidy.pl

I don't understand CFB, do you have an idea of how much the internal resistance of the tube will be reduced to? and what additional drive swing required?

I have noticed that some dual fets that Mouser was stocking seem not to be there anymore.

Are there any such duals that are available from them or other suppliers, besides LSK types.

Hi All,

Thank goodness for all the resources on the interweb! I look forward to joining your conversations.

I had a 30 year career in professional audio...recording studio then record company then equipment/services provider. For the last 7 years, I have been developing commercial PV solar projects. No circuit design for me...mostly management...but I do have a BSEE from way back when so I sometimes get bogged down with all the little details.

My first project: Restoring some 1963 Bozak B-302A speakers.

I have read through the Bozak Facebook group and AudioKarma so know all about the Tobin mods, enclosing the midrange driver, etc. I would like to do some measurements of my own to confirm things like my individual driver effeciency and frequency response in order to set my crossover points and required attenuation to the ideal (keeping it first order). Does data for the Bozaks drivers already exist somewhere? I need your guidence about where to start this project.

I have a trusty Radio Shack SPL meter and an Audio Control C101 Analyzer with mic but I'd like to utilize some newer tools. I have a fairly new Windows computer. I'm hoping some of the free RTA's are better than what I have. I am looking for tool and setup recommendations as well.

Enough of an intro? Thanks for reading and providing any comments/info you may care to share.

Hello everybody!

I just finished designing a 211 A2 SE amp, just for the curiosity. I'm not planning to build it: the objective was taking more experience and familiarity with mosfet drive and A2.

What do you think of the design, is there anything obviously wrong, or something that could be done better? The circuit is explained in the article linked.

Also I'm not too sure about the setting of the quiescent current in the mosfet, as you can read in the article I made a supposition about how it works.

I've uploaded it in my site:
http://www.giaime.altervista.org/hivolt.html

Feel free to make any comments!

Please note that this is not a project suited to beginners due to high voltage

I am thinking of buying a pair of Beam TPL-150 or TPL-150H for a new project including some Beyma 12p80ndv2 which I already own.
I have the opertunety to buy a used pair for a god price, or I can buy a new "matched pair" to almost twice the price...
Will the matched pair result in better sound quality?

I am using the an all digital Dirac Live based room correction unit from Mini-DSP (DDRC-22D) and also using active crossovers.

Can anyone kindly tell me if my drivers are blown? Thank you!

YouTube

Hey all. new here 3/30/2020 Am into all phases of sound /music as a keyborad player and tech of rhodes Hammond and analog boards like the Korg CX ,roland VK and oberheim 3 sq.. lookin for an oberheim 3square right now. Have built all my own P A cabinets/ stacks and now have a quick project to use up some junk.Think book shelf back channel, but still want the best sound out of em I can get. My question is where to find the best cabinet dimensions [actually only height] for what I am using, which ya'll might laugh at, but thats ok. Its all junk as in scrap literal leftovers. 4 drivers per cab. 1-4in KLH 8 ohm woof and 3-4 ohm 3in full ranger drivers all high end from old computer hang ons..lol I have 3 in deep [right now] ports too,. and i am makin the cabinets out of 1/8in clear lexan old cracked UTV windshields 5in x5in x ? tall..Thats what I need the best height to get the best volume for the best low end,etc.I have some 1/2x 1/.2 galvanized angle and rivets for the corners..still laughin? I am leavin em clear and thinkin they will have kind of a steam punk look to em. No stuffin and plan on trickin the wires to be seen inside.I don;t have any other info on these drivers...i am healing surgery off my foot a while and this covid gives me the time to knock this out..You can get me direct a hawgford@windstream.net. I do some car/ Harley audio as well,as buddy does custom interiors, got a big lanzar feedin a dual coil 8in that hides in the center console of my turbo 4 cyl ranger single cab , quick and loud sleeper,lol.Anybody with vintage boards needin repair or upgrades talk to me too..If I can figure it out ,i'll get notifications from here,but will check in, best to email direct.. thanks

LATEST STATUS UPDATE 2020-03-31
Our hearts go out to all those affected by the pandemic worldwide. The situation is changing daily but so far we have been lucky enough that there has been no disruption to our US origin shipments, and only minor disruption to our shipments from Italy.

SHIPPING FROM THE US
The company who operates our Massachusetts, USA warehouse and shipping has been deemed an essential service and is currently fully operational. Shipping is currently unaffected. Some small delays should be expected, but so far smooth sailing.

SHIPPING FROM ITALY
Hifi2000 who produce and ship our chassis have been given approval to operate a skeleton crew of staff and are shipping orders twice a week. Please expect a delay of 4-7 days on all orders that are shipped from Italy.

Re-anodizing of panels after working them is currently not possible.

Additionally it should be noted that while passenger flights are not operating on some international routes, we are not aware of any country pairs where cargo/logistics has not been considered essential and is still free flowing.

As you know the situation globally can change day by day and country by country. We will keep this post and the latest blog post on the store homepage updated with the latest news at all times, feel free to check back any time.

Stay safe.

Hi friends

I was tempted to build this interconnect: DIY Silver RCA Interconnect Cables

fun and simple to build. It seemed.
But when I started to source the parts, I found that I couldn't just blindly "get parts". The required ferrite-core does not tell much, my source lets me select specific impedances @ frequencies...
So I tried to find out about those details, but found nothing.
Gosh, where could I learn about it!
david

I would like to build a push-button solid state input selector with lots of inputs. Never done this before after having terrible experience with a Quad pre-amp about 25 years ago. I think it used 4066 c-mos switches and was quite un-reliable.

Just wondered what the latest thinking is for about 6 Hi-Z 10K line inputs with low THD. feeding straight into a volume control.

I don't want to go over complicated with arduino etc preferring simplicity with no pulse artefacts. - Any suggestions, - latest IC's etc would be welcome.

Thanks.

Has anyone built the DIY Menno Van der Veen 70w or 100w tube amp which uses the Plitoron torroidal power and output transformers. I am thinking about using this design for my first tube amp project and was wondering what the DIYers out there have to say about this amp. My current system is bi-amped with 100W and 200w solid state amps with an active crossover. The tube amp would be used to drive two PHL 1240 mids and Raven R2 ribbon tweeter in a MTM with an overall sensitivity of abot 95 dB. I would use a 200w solid state for the 12" Lambda bass driver. The info on the Van der veen's tube amp can be found at Plitron.com. Thanks

So I've been trying to get bluetooth working on my diy boombox and I've been running into some issues. I bought one of these: Amazon.com: Esinkin Wireless Audio Receiver for Music Streaming Sound System Works with Smart Phones and Tablets, Wireless Adapter for Speakers: Home Audio & Theater and installed a voltage step down chip? board? (idk the technical term) so I could run it from the boombox's battery at 5v. The receiver works fine, but at very low volumes there is annoying feedback and chirping. I tried powering it with the provided power supply and there was no feedback, but as soon as I tried powering it with the boombox's battery, I got static and hiss. Is this a grounding issue? I'm not very familiar with electronics, does anyone know what's causing this? It doesn't seem to be affecting sound quality, but it is very annoying at low volumes. It reminds me of a $5 portable speaker 🙁 Also, I have checked the output voltage of the step down and confirmed it's giving me 5v, if that's relevant.

Hi all,

I've been running my rebuilt Fisher 500C for a while now and it sounds great, really enjoying it but...you know how this hobby goes...always looking for an "upgrade". Also, the Fisher is a big unit that I really don't need all it's functionality. I really only listen to vinyl on it. Also, I love the look of tubes glowing and they are hidden away in the Fisher. All this to say, I'm looking at options for a separate tube pre and amp.

Here's my setup:

Sources: 2-3 turntables running at any given time (TD-124, ARXA and Ariston RD11s currently)
Speakers: Klipsch Forte 1's (I have Bob Crites crossover and tweeter upgrades but still need to install)

Ideally, what I'd like to get is a preamp that allows multiple phono inputs (at least 2) and have option for both MM and MC carts. I'm not currently using low output MCs but that may change. And since vinyl is all I listen to, I want to keep that option open.

For the Amp, I just want great sound with very low floor noise. SET, push-pull, 300B, stereo or monoblocks...I really don't know and would welcome advice here.

Budget: I started looking at used Mac gear (I always loved the look of Macs and dreamed of owning some). The C2300 preamp is amazing and fits my needs (I think) but used runs $4K+CAN. An MC225 or pair of MC30s would be great amp choices but again, I'm looking at least $3K there. So I'm thinking, maybe there's options to get close in performance to these Macs for significantly less that $7K? Enter possible kits.

Kits: I've looked at Elekit (vkmusic), Transcendent, Tubelab, Dynakit, bottlehead and tubes4hifi. I was really considering tubes4hifi for both pre and amp but then read some really disturbing reviews specifically on the preamp and the customer service. The Transcendent stuff looks really cool. Tubelab may be a bit too DIY 😉

Skill: I'm not an electronics wizard by any stretch. My skills are more in woodworking but I've built lots of speakers and soldered crossovers and even recapped a few old ones. So I would need basic level instructions, reliable kits and access to help such as forums like this one.

So, I'd welcome recommendations that would fit my needs, skill and budget (which is sorta flexible below that $7K mark, at which point I'd just get the mac gear).

Thx

I'm using .27R resistors to drop heater voltage from 6.3v to 5v, but when I measure with my DMM they measure higher, around .5R. I also tried putting 4 in series and got 1.4R, which is better but still a bit high. Is that just the tolerance of my DMM? The markings on the resistors are correct.

In my years of doing home entertainment installations and tune ups I've never run into a problem quite like this one, so a little advice would be appreciated.

The stereo system is oriented along a wall with openings on each side. One side is a hallway the other goes to the dining room. The kitchen is right behind the speakers.

On this wall one side of the wall is hollow, with the kitchen wiring running through it. The other side is solid. It is constructed from sheetrock on steel joists.

When I bump my fist on the hollow section of wall it rings at about 100hz, quite noticeably. When you sit opposite you can hear an echo returned from this section of wall... it's very reactive and it's affecting the sound from the stereo setup in some pretty horrible ways.

My first thought was to drill a couple of small holes and fill it with construction foam... A second thought was to cover it with cork and paint it. The client suggested ceiling tiles ... But I am unsure any of these measures will work plus it has to look okay in a living room.

Any and all suggestions would be appreciated...

Has anyone here built this kit? If so, what do you think of it? I have one on the way and may need some tips. TIA

So, just thinking about a bit of a different valve project. Has anyone ever come across a valve schematic for a theramin?

I'm sure this has been discussed numerous times, but I did a search and only have so much time to sift through threads. Sorry about that.

What happens when you use digital EQ to push f3 lower in a sealed box? I have 4 of these in a ~1.83 ft.³ or 52 liter enclosure. PE site says one in 1.53 ft.³ / 43L has f3 49hz. I would like to get close to 40hz. If not practical it's fine, I can use subs. I'm in a concrete apartment and listen quietly without much bass anyway. But it would be nice to get these down near 40hz.

Also fs is 52hz, but I think I remember reading that going below fs in low freq. isn't a big issue.

Also if you wonder about the arrangement of 4 drivers in a smallish enclosure, I'm making sure some things are feasible and then will make a build thread. It will make sense...maybe

I've used one of these (came assembled with pot) to build stand alone spring reverb for my mixer return channel. I've just used L channel for input and R for output, volume on max. Nothing else. It turned out to be a perfect gain in/out, sounds just fine (for a spring reverb) and has very little noise compared to my previous transistor build. But that's only the application I did with these.
How good actually are these chips when it comes to audio quality? I think these could be handy for building lower gain preamps etc. But would the sound quality cut it for HiFi or even a studio project? Apparently these are digitally controlled so distortion is minimal, not that I understand how it actually works 🙂
Cost is near nothing.
This is what I used here
1-10 x PAM8403 5V 3W+3W Mini Audio Digital Amplifier Board with Volume Control G | eBay

I built the lx.mini cover last year to use it with my Spatial MT4’s. I alternate between a pair of diy Ripole sw’s using 12” Peerless woofers and a Vandersteen 2w. With the 2w the xover is set at 85 hz with a 6db per octave slope for both the low and high frequencies. The blend is very good and produces a very natural bass albeit being monophonic.

With the Mini dsp I can change xover frequencies and slopes and get fairly good sound. With the LX I set the xover at 110 hz. It really works pretty good also. Not as a low response as with the 2w though. The 2w gives more of a taut response, having a q of 0.5. The Lx results in a better sounding system that the mini dsp provides; more transparent and refined.

But, ... here is my question: Why do I have much more volume range for the low frequency with the mini dsp than with the LX? With the mini dsp I can get the sw output to sound much louder.With the LX the sound level range for the bottom is more limited.

The amplifier used for the sw’s is the Crown 1500 which has a volume control. The LX volume pots are set to their maximum. Thanks for looking.

Need help with fixing bass response of my nad c372 integrated amp. Recently while playing music volume increased for a couple of second and came back to normal level by itself. This volume fluctuation happened twice. Post that tone defeat button stopped working. Bass response got drastically reduced, mainly the lower end of the bass became too silent. Only the lower end of bass got disappeared and other frequencies are playing fine. while playing bass heavy tracks, bass feels incomplete. It has lost its punch. Also, pressing the tone defeat button is not increasing the volume Like it used to. There is no audible difference between tone defeat on/off but can hear some crackle sound when button is pressed. Please help me on what to do for this problem.
Mine has a v5 board if it helps.
Thankyou for your time.

Greetings

Just discovered this intriguing piece of audio history known as the Karlson acoustic transducer (thanks FETHead):

http://home.student.utwente.nl/e.j.j.ulfman/

Has anyone done any real empirical testing of the Karlson design? I did find a Norwegian commercial derivative of the K-Slot concept:

http://forsman.no/hjem.htm

More than a 'cult'? Opinions???

I have just learned that Manu Dibango died from covid-2019:

COVID-19: Famous Saxophonist Manu Dibango dies at the age of 86 | Africanews

Regards

Charles

I've posted an embarassing number of threads about Unity horns, going back fifteen years.

Something that's been a big challenge for me is the cost and crossover demands of three way loudspeakers. Basically it's a million times easier to make a two-way speaker than a three way speaker.

When going from a two way to a three way, the crossover tends to get about twice as expensive, and the complexity goes up like a hockey stick.

I had an idea, inspired by my last project that might make it possible to do a full range loudspeaker with controlled directivity using a two way.

I know that it's possible to do a two-way controlled directivity speaker if you put a full range speaker at the apex of a waveguide, like xrk971 did here, or if you use a large format compression driver, like weltersys did here.

But I have a thing for small tweeters and small compression drivers, so those solutions don't work for me, unfortunately.

Hi, complete newbie here to loudspeaker building. I'm trying to find a dipole tweeter to suit my Coral Beta 10's in open baffles (Slot loaded open baffles). I bought a pair of Aurum Cantus AST 25120 air motion transformers, which should suit the Coral's sensitivity nicely (95-98dB). The frequency response looked quite flat on the spec sheet (see attached pdf). However, I did a quick measurement on them, and found a huge dip above 10kHz (-10 - -20 dB). I measured them with Room EQ Wizard from 3k-22k without crossover, straight from both my 300B amps and a Denon transistor amp. Am I doing something wrong?

Many moons ago I had the schematics and instructions to mod and upgrade my Novacrons. I have since moved, and have found all the parts I ordered, but not the instructions. Does anyone have these instructions available as they are not online anymore. I remember one part was to put resistors from the output tubes (Cathode) ?... HELP!

Sad news. This afternoon a friend from Argentina called and told me that Juan Esteban Frind, aka Popilin, had died. The incident occurred on August 20, was 55 years old and had recovered from pneumonia. Only God can give us the answers to the mysteries of the death of young and healthy people. To this great member of whom I got a friendship that deepened with the passing of time, he who never boasted of some titles, had a deep capacity to solve physical and mathematical problems. He always said he was simply a TV repairman. Their discussions about the problems of magnetism in audio transformers were known. It has left us with no possibility of response, at least on my part, not having followed him lately in which it was known that he had serious economic problems due to the problems that accused his country. He lived in Villa Dolores, province of Córdoba and I hope, rest in peace my friend.

Need help with remaking connections around q4 it burned some trace and I don't have one to compair.

Would you try to bridge an fill in this damage to the edge of the ground plane or not worry about?

The damage is located on the back side of the board around the rectifiers.

David

Manfred huber

I apologise up front for any stupidity on my part - but where has Manffred Huber's website gone?

I have most of his articles stored on a computer that is now in storage and I wanted to look at his Shunt Regulater for a possible project

Mvh

Not sure if it's the right forum, but sounds like it is.

A very noob question but I did not see clear responses for that in a single summary place.

While looking at the pictures of builds, it appeared that some capacitors, resistors, etc. are soldered directly to switches, transformers and so on... likely to avoid artefacts, noises, etc.
Any good advices regarding these settings (what to use, where to use, for what)?

I'm looking for a pair of Vifa tweeters, and woofers

ERYN's TU-8800
"Tried some 6F6GT today and it sounds very good!"


Here is the Lundahl PCB board for TU-8800
Lundahl C-core LL2783C will be available next week - March 3, 2020

or have a source (preferable) of just the VFD display part. Or a player model utilizing it? TIA L

So I got two stereo Wollensak tape machines for cheap, and intend to use the power transformer for a 6AQ5 stereo amplifier. While they are being shipped, I downloaded the schematic (of a mono Wollensak, couldn't find t-1515 stereo schem) and saw this for the power supply:




I know a little about power supplies, but this I don't understand. Is Wollensak using line voltage to make filtered 250 VDC?? Is there a way to make this transformer (I assume the stereo one is same) work in a 6AQ5 amp, or ought I just look for a more conventional PT? Thanks!

I have been building speaker projects for years but now I want to build my own headphones from scratch. However, I am not sure if the same principles would apply. I really want to make something unique completely from scratch and not use existing headphone drivers (this is the same as buying already known headphones).

What I'd like to do is use a 3" full range woofer from Mark audio and position the driver inside cups so that it is roughly 1" from the year. Would this work or sound good?

Finally, how do I make sure that I get a flat frequency response from the highest to the lowest frequencies?

Any help would be much appreciated. Thanks guys!

I've noticed theses speakers and most of the people who heard them rave about them.
Also, this review is quite interesting http://kiiaudio.com/en/component/ph...?download=2:audio-review-test-09-2015-english

Has there been such tryouts in the DIY section?

I bought this B&K Reference 125.7 amp with 6 out of 7 channels working.
Have been looking for this or the 200.7 for 3-4 years and knew I could only afford one if it had a bad channel or two. They are still bringing decent money some 20-years later.

The blown channel had actually blown off the traces where the lateral mosfet had shorted at the gate resistor. So I tested all the remaining 6 channels and they were working fine. And went about replacing all 4 output FETs with Exicons, matched best I could with the 8 I had on hand (all of them were quite close).

Powered up and was not getting drive to the outputs, so I ordered new drivers BJTs (2n3440 and 2n5416) from Mouser. Even though they tested good out of circuit. Installed the new parts and that channel was working.

Bad news - while testing why the outputs were not getting drive, I shorted a resistor and blew a trace off a working channel, as well as the negative side rail fuse for that same channel.

Repaired the traces, resistor and tested all pre-drivers, replacing any that tested as bad (I think there was 3 on one channel and 2 on another).

Now it was working 100%:
All Channels working and set bias and played for over a week off and on - probably 20-30 hours in total at normal listening levels. I also dummy load tested each channel at 70% power on my O-Scope and all channels looked to be working. Sine was smooth, clipped as expected and got about 185W at 8r and 235W at 4r on all 7 channels.

More Bad news - and a weird happening:
I put the amp in my HT rack, with brand new XLR cables and watched 2-3 movies and my son played xBox for about a week. After about a week, I finished watching a movie with my son and I wanted to feel how hot the amp was getting and make sure ventilation was adequate.
I touched the top of the case and heard a "crackle" (a small 1-2 second buzz, then pop) through one channel (Right surround). The case was warm but not hot at all, probably 35-40C, which is slightly more than is ran on my test bench for a week.

I turned it off and when I turned it back on 2-3 minutes later to see if the "crackle" was still there - DC out of that same right-surround channel and before I could turn it off, it had a loud BUZZZZZ and blew the woofer (5-1/4") in that surround speaker. Now that channel is dead - no DC being output?

I pulled the amp, tested all the other channels (they all work fine) and this channel was a working channel when I bought the amp, but was one of the effected channels by my "mis-hap" with the DMM probe.

Long way around to the questions:
- I have tested the (2SK1058/2SJ162 - 1 pair each) outputs and they test fine, both with DMM out of circuit and 2 different eBay testers
- I have tested the drivers (2n3440/2n5416) and the only strange thing compared to a new part is the old parts Ic=6mA, where new part tests Ic= 1mA, this on the eBay testers, not an actual test jig though.
- I have tested all the pre-drivers and they all tested within spec. I also verified all resistors and diodes are in spec. and working, pulled the caps and verified with a tester within spec. All rail voltages are within spec too.
- Is this possible that the drivers going bad, could cause DC on the output and fry my woofer? Then blow the channel without harming the outputs or blowing a fuse?

Any assistance would be appreciated, as I'm confused why on the drivers are testing bad and would do anything but not turn-on the outputs?
I have new parts coming this weekend, but I can't find an exact schematic (there are similar versions with different FETs, but not exact), but doesn't appear to be very complex design either. The only strange part is it has +/-65V (red/black) going to the 4 channel board, and also has +/-65V (Red/Orange/Black) along with Ground (Green). Not sure why it needs two wires carrying the same rail voltage, but I think it is a mute circuit possibly, testing if there is full rail voltage (guessing though).

Hi guys,

I´m new in speaker building and I hope you can help me with a problem.

I´m currently working on a couple of simple full-range Bluetooth speakers I want to build for a cabin we have in here in Mexico.

I have been doing some tests with different types of amplifiers, speakers and power sources, but it doesn't matter what combination I use all of them are really loud and start to distort at half the volume.

The biggest issue is that we are renting the cabin for the weekends and holidays and everybody that rents the house will have access to the speakers so I know some of them will play music at full volume and I don´t think the speakers will last.

I´ve been taking some measurements of the voltage of the output of the amplifiers to calculate the RMS watts each amp is giving and none of them go higher than 15 watts and all of the speakers I have are at least 30 watts RMS.

Here is a list of all the components I´ve been testing.

Speakers:
- Dayton Audio PC83-8 3" Full-Range Poly Cone Driver
Dayton Audio PC83-8 3" Full-Range Poly Cone Driver

-Dayton Audio PC83-4 3" Full-Range Poly Cone Driver
Dayton Audio PC83-4 3" Full-Range Poly Cone Driver

-Dayton Audio TCP115-4 4" Treated Paper Cone Midbass Woofer 4 Ohm
Dayton Audio TCP115-4 4" Treated Paper Cone Midbass Woofer 4 Ohm

-FaitalPRO 4FE32 4" Neodymium Professional Full-Range Woofer 8 Ohm
FaitalPRO 4FE32 4" Neodymium Professional Full-Range Woofer 8 Ohm

Amplifiers
- TPA3110D2 2.1 Channel Bluetooth 4.1 Digital Amplifier Board 2 x 15W + 30W with Volume Controls
TPA3110D2 2.1 Channel Bluetooth 4.1 Digital Amplifier Board 2 x 15W + 30W with Volume Controls

- KEYREN Power Amplifier Board, Digital 2.1 Channel Amplifier Board Bluetooth USB TF Input 50W+50W Stereo 100W
https://www.amazon.com/-/es/KEYREN-...etooth+amplifier+module&qid=1585454385&sr=8-9

-Cuawan ZK-502L Mini Dual Channel Stereo Amplificador 5.0 Bluetooth Amplifier Board Wireless Digital Power 2 X 50W
https://www.amazon.com/-/es/ZK-502L...tooth+amplifier+module&qid=1585454817&sr=8-12

- AOSHIKE DC12V-24V 2.1 Channel TPA3116 Subwoofer Amplifier Board High Power Bluetooth Audio Amplifier Board 50W+50W+100W (Bluetooth Amp)
https://www.amazon.com/-/es/DC12-24...&sr=1-52-dd5817a1-1ba7-46c2-8996-f96e7b0f409c

Power source

- 12V 1Amp

-15V 4Amp

-18V 3Amp

Is there an easy way I can limit the volume or gain on the amplifiers?

Hi,

I have been fiddeling around with my 8 + tweeter for a really long time, and I think they are awesome.
For music duty they are more than enough, but now I am putting them in a bigger room where they have to double duty for music and movie/gaming for the rest of the family as well.

I don't play really loud and I don't care if I dont get that last octave. But I want punchy, articulate bass and a speaker that can handle full range material. And around 91-92db/ 2,8V after baffle step.

I'm planning to cross over at around 200hz.
I have 3 options I have been thinking about.
Eminence Legend BP122 in closed cabinet, Eminence Kilomax Pro 18A in open baffle (Troels Gravesen style ob15) or the bass section of Bill Fitzmaurice David (I used to have 2 Lab12 loaded THTLP's which sounded awesome).

Cost wise these 3 options wouldn't be too far off each other when the cabinets are taken into account. (The 18 inch will be a bit more expensive)

So any opinions or adwise?

Despite the technical nature of the discipline, the appreciation of sound is ultimately a subjective issue.

I don't "make" things. I cannibalise broken or damaged speakers.

A desktop system brings different challenges. Your feet are generally 18" away from the sub and each satellite is only a couple of feet away from your ears. THe underside of the desk acts a low ceiling causing the sub to sound boomy.

I bought a cheap Bush sub from Ebay for £5.00 ($6.00). BUSH CHT100DVD HOME Theater System Subwoofer (NN) - PS14.99 | PicClick UK Beneath the macho (8") cover on the side-loaded driver is a wimp of a 5" unit. I have replaced this a 6.5" bass driver salvaged from a TDL studio 10 Studio10.

For the satellites I purchased a pair Ariston MX-30 (£10). Superb Bookshelf Speakers For Sale in Sprotbrough, Sth Yorks | Preloved

I am super-impressed by the results. It is probably the best sounding desktop system I have owned. The original unit was more than worth it just the port flare and the 100w plate amplifier.

Dear All,

Can you help me identify this potentiometer ? It is an APLS PCB 10mm, with a value of 20kOhm. What I do not understand is why it has 5 pins.

It comes from a Zoom RhythmTrak RT-223.

Regards,

Davide

I came across a set of old Group Buy boards. Anybody recall the build threads for these boards?

• I think the green boards are Chad or hifizen Aleph-X amps Dec 2002,
• One set of red boards are X-BOSOZ layout by KH 2005
• Other set of red boards are Aleph-X amp layout by KH Dec 2005

If memory serves the Red Aleph-X boards were good, but needed one trace cut and rerouted.

I'd like to build an A-X, but probably won't build both. Appreciate any help or guidance for build threads or which is better than the other.

Thanks!

Don't know if this is in the right section but here it goes:

As I am a lot at home now because of the Covid-19 it's time to do some stuff that is on the "to do" list.
One of those things was to refurbish my marantz 2265B receiver a little bit.
It has the usual intermittent contact problems etc.... normal for something that is 40+ years old. Hasn't been touched as far as I can see (yes it is older then me, got it for free a few years ago).

So I cleaned every switch/pot and replaced al the electrolytic capacitors in the power supply/preamp/phono pre/output amp.
I left the tuner electrolytics in.
I checked DC offset of the output amps and checked the bias. I also cleaned the DC offset and bias trim pots.


Then I used a test transmitter to adjust the RF section. The discriminator Transformer coil was a little bit of, as do some of the RF stages.
Reception is a lot better now

I also replaced al the fuse lamps as they where all gone.


So after this process al of the switches and potmeters work again like they should. Sound is a lot better. Look a lot better also.

There is one thing that remains.
When the receiver is turned on and still cold one channel is down in volume/distorts. Putting some more volume makes it become good again.
I checked the RCA connectors as they have a pre/main output so you can put an equalizer or something different in between the pre and output amplifier.

So after some reading it looks like some of these japanese transistors can go "bad" and develop some weird intermittend problems.
So I was thinking of replacing some of the small transistors on the preamp and at the input of the main amp.

The transistors are:


2SA798 (double PNP transistor)
2SC1345 (NPN)
2SA722 (PNP)

I could maybe do the phono stage as wel:
2SA872 (PNP)
2SC1885 (NPN)
2SA912(PNP)

So most of these are (ofcourse) obsolete.
Any ideas about replacements?
The double PNP is a difficult one.
For the phono input having lower noise is nice but the noise is not a real issue.

Hi all,

i'm actually looking for a schematic for an tube preamp or buffer with an ECC82 per channel which will run at roughly 70V (48V rectified and filtered).

I really want to get behind the "witchcraft" of the circuit. So i need some explanations which value is calculated in which way.

Before i get ripped apart for using ether an ECC82 or only 70V:
I want to drive a ss se amplifier with this (that lovely 2sk1058 mosfet amp from Mark Houston) and i got 2 tubes and two transformers already. Even the case is allready there. That's why i'm asking for a schematic which will use only 70V as B+ (if an voltage doubler isn't preferrable).

It must not surpass the High End region. It will be there to glow and to control the volume.

So if someone can give me a hand with this 🙂

Hope you get what i'm talking about in my way of english XD

So I have this magnificently destroyed amp to deal with as you can see in the photos. I need help finding the rectifiers.

I did a search on the part number on the package and google turned up nothing.

Transformer became so hott some of the windings came out of the board. I have alot of work ahead of me.

This is Sophia Zeng from King Credie Technology Limited.
We are the PCB partner of MIT in China, you can find us in their website and blog.

We are committed to providing high quality and fast PCB services for global customers, not only providing PCB manufacturing.

KINGCREDIE service including:

1. We have many engineers with more than 10 years experience in engineering design and production; they can provide a professional advice including engineering data design/optimization, cost optimization, material selection and etc.

2. We have process control ability for high precision PCB samples/small volume to ensure the quality meets customer’s requirements;

3. Satisfy the limit of urgent delivery, sample 2 layer----24H, 4/6 layer----48H, 8/10 layers----72H.

4. 24-hours hotline service (including after-sales service)

5. Provide sample and small batch assembly services

If you need a PCB partner who is focused on growing & developing with you, please trust us, trust MIT’s choice!

Best Regard,
Sophia Zeng

King Credie Technology Limited
Tel:+86-0755-23110700
Fax:+86-0755-23110701
Phone:+86 135 7086 2074
Email: sales002@kingcredie.com
Skype:sophia.zeng1993
Website: King Credie | Printed Circuit Board (PCB) Manufacturing | Online Quote

This from a recent article:

“Amazon Music HD offers customers more than 50 million lossless HD songs, with a bit depth of 16 bits and a sample rate of 44.1kHz (CD quality). In addition, customers can stream millions more songs in Ultra HD (better than CD quality), with a bit depth of 24 bits and a sample rate up to 192 kHz.”

Anyone have any idea if the Ultra HD format is just resampled from CD format?

I am currently building a small system for the office and was just pricing a new DAC either buy or build. The availability of a wide selection of 24bit/192Khz material will definitely impact my selection process …maybe not buy a Schiit Modi Multibit??

--- ALL 3x MODULES ARE SOLD ---

Hello Everyone
This is my first question m asking here.M new here, So sorry if i forget to clk something or mention something or whtever.

I have made a 2.1 audio system using 2- 5inch woofers as mid way speakers and 6inch woofer as woofer. Everything is going good but the woofer enclosure i made isnt producing tht much base, it just producing "punch" type bass not deep bass. The bass is just coming from the woofer not from the vent and covering the vent didnt effect tht much.(See the enclosure design (i) in attachments.

I doesnt like punch bass, i like the "echo" type of bass (or deep base i dont sure wht to call tht type of bass).So i searched a lot and i found that to create a deep base i have to add larger path difference between sound from front side and back side, so i m thinking of a different enclosure (see the ii design).
I didnt create the enclosure yet coz m not sure if it work or not (thts my problem).M thinking to use pvc pipes in "curly fashion" to increase the path difference. So i want to know will this work or have to add something more?? Do i have to fill the downward space with something??Wht should i do now??
Btw in design ii i showed tht the path is like "S" (coz i showed in 2D) but actually its is more likely to "spring shape"(sqaure spring or whtever).

And my woofer box vibrates too much thts why sound get distorted too much, wht should i do to stop it or decrease it, currently m using heavy weight to stop its vibrations.

Again sorry if i forgot something,Now m waiting for the answers 😀🙂😀🙂

I was curious if there was any music specifically for headphones.

As kids my brother and I played around with music for headphones by making
recordings using two microphones back to back and about 6 inches apart then
playing music through the stereo speakers that were 10 feet or so apart.

Is would seem that it would be quite interesting to place the
microphones in the prime listening spot and have an orchestra play.

Is anyone doing such recordings?

Thank you

Can anyone who has a Krell KAV 300CD please measure the secondary outputs of the transformer.
I would be much appreciated
Thank you Paul

I have a pair of 2214H woofers l100t from JBL speakers I aquired. They are in good shape and work. Have heads they were solid woofers. Would rather them be appreciated than not used. I've looked online a little at the few I found selling to see what they are being sold for. I will consider all offers as I'd like to sell quickly and have someone put them to good use. My direct email is mattcorronjr1989@gmail.com thanks

Hi.

I have a pair of 751 and a pair of 751 Freedoms. I have recapped my Cyrus One with great success and now wonder if I should upgrade the components on the 751 crossovers, rewire them inside, and mess about with the filling. Does anybody have a circuit diagram for the crossover(s) and any experience of modifying them.

Many Thanks.

Hi Everyone!

This is my first posting as a new member.

I bought a Forte 1A a few months ago. The left channel always causes the speaker to make a "pop" noise when the amp powers up. Also, after preamp and amp are powered up there is a low frequency hum coming from the left speaker. Not sure if I can hear the buzz from the right speaker.

The left speaker also makes a "whoosh" sound when powering off the amp.

Has anyone else experienced this? Should I be concerned about maintenance?

I am a bit new to this hobby and do not know much about this amp.

My setup:

Speakers: Ologe 5, LS 50 wired, Magnepan LRS
Amp: Forte Audio 1A
Preamp: Bryston BP 26



Thanks!