Hi All, Greetings.


2 years back bought a new bookshelf speaker, but found its tweeter were too quiet, causing muffled mid-high freq. The speaker is bi-wirable, so I connect bi-wire to my amp's Speaker A/Speaker B. When running the tweeter on its own, I can hear it but it was a little quiet (less energetic), once switch on mid-bass (usage of bi-wiring), it will overpowering the tweeter, causing the entire sound spectrum to go low-mid to low. It was like a layer of cotton blocking the tweeter, restricting its output.



So recently I swapped the crossover with another smaller bookshelf from same company, now the speaker transformed by opening-up highs and sing, sounds good! So I thought of modifying the original crossover.


Referring to my attachments, the original crossover seems to have higher resistor values and more resistor and capacitor on the tweeter section compare to swapped unit, I'm not sure how it works. I was thinking to lowering down R1 to 3 ohm and R2 to 1.5 ohm, is this a good start? Speaker Spec as below:
Original Speaker:
2 way bookshelf speaker
165mm mid-bass driver
2kHz crossover
45Hz - 30kHz spec


The Donor's Speaker:
2 way bookshelf speaker
130mm mid-bass driver
3kHz crossover
58Hz - 20kHz spec


Thanks.

Hi, I'm using the CSRA64215 to equalize a small speaker and I'm using the Speaker PEQ bank to do this. There's also the User PEQ bank. I've found that I can't save the settings of the User PEQ bank to DSP memory, it is reset at every power up. Can anyone confirm that or tell me how I can save these settings.

The User PEQ has different presets, how can these be changed by the user of the speaker without resorting to the SPI programmer?

Thanks for your help

Good evening guys

I am offering a set of CSX1 SONY VFET amplifiers from 2014 with a pair of 2SK82 & 2SJ28 Sony VFETs that I got from Nymeria. bought. I would have € 95 shipping included.

Hi Gents,
Came across the Hilding horn using Faital Pro 3fe22.
There was no mentioned of sensitivity, does anyone know
it's value ?

Thanks

Need some help to identify the humming toroidal transformer of my audiolab 8000a amplifier . Transfomer labels just says "Talema" Audiolab 9802-P1S2. My S.no is 207B88566 so it should be a B seried but not sure if it's a MKII or MKIII version (anyone knows??).
There are a couple of threads here and here trying to figure it out so I just wanted to be sure if this ONE is the right one, a Talema toroidal transformer 21755-p1s02 225va 2x30v 2x3,75a ??
I really have not much familiarity with electronics and measurements to understand or figure it out myself...

Hi, I have an older MHDT Havana dac that will play tidal MQA but not qobuz hi Rez. My RME adi2 will play both hi Rez and MQA. Both dacs source is a Auralic G1 streamer. I would think if the Havana would not play hi Rez it would also not play MQA. I'm using a USB cable on the Havana and digital rca on the RME. Am I doing something wrong or is that how MQA and hi Rez work on older dacs. I believe the Havana is 10 or so year old r2r dac. Thanks for any suggestions or help.

Someone tell me I'm mad!!!!

I've always been led to believe that proper digital coax RCA spidf was better than Toslink for hooking up CD Transport to dac.

Tried a cheap fibre optic Toslink today, and "I think" it could be better, ever so slight grain not on Sade's voice any more, which I thought was "natural" with the RCA, and seems to be more air around everything, even the bass.

Cheers George

A noted Tube Guru shares his thoughts.

Hello guys,

I would like to ask if a 5k Output transformer be a good choice instead of the 3 to 3.5k that is specified on the schematic? I really would like to get some thoughts about this.

DIY Audio Projects Forum • Information

Here is the schematic with actual measurements from a builder.
Thanks

Hi,

I would like to ask if there's a target ratio between harmonics (2nd, 3rd, 4th, etc...) and phases that you chase to get an ideal THD, or at least some guidelines to follow. I've found something here ( https://www.diyaudio.com/forums/tubes-valves/362361-check-harmonics-thd.html ) but not so much.

I've some PP designs that have a predominant 3rd harmonic and then all others at least 10 times lower, I have some others with odd harmonics that are reduced to 1/3rd of the previous ones, others reduced to half the previous one, etc...

What is the preference in SE designs between even and odd harmonics?

Do you generally prefer to have lower THD at low to medium power, then a steeper slope of THD at high wattages, or a sacrificate the THD at lowest volumes to have a flatter THD vs Power curve?

Resuming: what are you looking at when designing a new amp in these three fields?
- ratios between harmonics;
- phases;
- slope of harmonics vs power.

Thank you in advance
Roberto

Amateur Audiophile please be gentle.
I have downloaded PSUD2 and experimenting with component values of CLC power supply for RH84 SE amplifier. Am looking for ideal values to aim for. Being noob I dont know how much ripple amplitude will be OK or such things. My Secondary supply is 0-250V separate for each channel. I have tried various Capacitance value after secondary; various choke values and am getting 2mV to 10mV (Third column in the PSUD2 software).
Best would be if you can give straightforward component values for two capacitors and choke (current and ohms ratings) as I dont want to go overboard but still have more than enough margin to be safe for my first build.

Secondary unrelated question is
RH84 amp blog says output transformer of 5k-6 K primary and 8 ohms speaker load. A friend here has 7K primary and 8ohms secondary.. Will that work ? My speaker choices would be limited and probably comparatively I will get little less power output and little stress (?) on output valves if volume increased ?
thanks and regards

I am thinking about a first watt build of mono blocks. The simple way is one channel in each chassies.
I was wondering if you can conect both output boards and therfore 25w pc becomes 50w monoblock

Dynavox VR-20 is vacuum tube integrated amplifier with power: 4 x 6P6P, pre: 2 x 6F2. Outputting 2x10W. If the tube types sound strange: 6P6P=6V6GT 6F2=ECF82

I wonder how biasing is sorted with it. Is it cathode biasing?

Hello,
I know this is a tight space but anyone have any recommendation for a driver that will perform well in a 12 liter enclosure please. Either sealed or ported but if ported, the port will need to be on same face as driver. (Bit complicated to explain why so I'll leave it out for the time being)
Many thanks in advance imk

In most cases the mentioned IM values are above the THD values. But there are amps, where this is reversed, e. g. by the Altec 9444B, go to
Altec Lansing Professional Amplifier 9444B Specification List page 6
Is this possible in general, and if yes, what means this for the audible perception by listening tests?
So far I have never noticed this detail.

Hi!

I need advise for making a great fullrange bookshelf. What Driver would you use and what kind of enclosure would you Do?

Thank for your help✌️��.

Hi,

Does anyone have a user manual for the above signal generator that they can share? I'm having difficulty getting mine to do a sweep - not obvious so need to RTFM...

Regards,
ac

I'm going to build the Integrated Amplifier with USB DAC, Power Amp and Headphone Amp. Does that usually need separate Amps? How can I switch DAC output from one Amp to another? Should I use a relay connected to this kind of headphone connector?
5pcs, 3.5mm (1/8”) Female Stereo TRS Headphone 5-Pin 3-Conductors with Switches | eBay
Thanks!

Now finally the plan in English is ready. The Stick is a double bass reflex enclosure for a single Tangband W4-655SA. The response curve is flattened with two notch filters. In room conditions it goes well down to about 50 Hz, this means Subwoofer is not a must.
In comparison to the Needles they have a better efficiency and are able to cope with higher volume levels because of about double Sd. I mean, they are still quite small chassis and you are not in danger to blow yourself out of the door (for this exercise I have constructed the "Viech" 😉 ). But in small or medium listening rooms you get really nice volume levels for such a small speaker.
I tried to get the sound as near as possible to the Needle, which I like extremely well, and I think it worked out quite well. There are small differences, the Sticks play a little bit more dynamic and analytical, the Needles a little warmer. But the difference is extremely small, I don't know if I would really pass a blind test.
Here is a picture of my pair:



Here is the plan:



Here is the frequency response without the notch filters. You can see a rather flat hill in the mids and a resonance peak at about 7000 Hz.



Here is the frequency response with both notch filters. The one consisting of only C and L filters out the peak, the other one flattens the mids. The raise in the heights is not flattened out, because it softens off-axis. So I recommend to place the speakers in parallel and not turned in.



Nice greetings, Berndt

Hello,

I’m trying to understand the point of an 845, 211, 805, etc. amplifier. Let me explain:

From what I understand, all things being equal, and assuming competent circuit design, parts quality, etc. the more gain stages an amplifier has, the less likely it is to be linear. And, from what I understand, generally speaking, the more transformers involved in a circuit, the more it will suffer from transformer-based distortion.

I’ve never heard such an amp, mind you, so maybe the proof is in the pudding. But as a general observation, all of the amps that I’ve seen that use these tubes in their power section are all preceded by something like an input tube such as a 6922 or 12ax7, followed by a 300b or 6L6 section (described as the driver section), then followed by an 845, etc. Or, it omits the input section and requires a separate preamp. In any event, all of such amps seem to have a veritable village of transformers stacked around these tubes, or because of weight and space limitations, stacked in a separate case.

Are these amplifiers really more linear than say, a El34 ultra linear amp running in class A designed with, again, a quality circuit, parts, etc.? Is there something super special that I’m missing in an 845 SET amp (line magnetic, for example) that can’t be achieved in a 6p15 SET (Decware zen Torii, for example) plus a quality subwoofer?

I would like to build a balanced VFET gain stage for my big VFET amplifier or for in a preamp.
I have found several old schematics on the internet and mostly 'shunt regulated push-pull' (SRPP) schematics. But none of them is balanced.
To transfer it to balanced I have made this schematic.

Can you shoot on it? Give hints and tips? Or burn it down and explain why it will never work or will never sound well 😀

Otherwise I'm going to experiment with it on breadboard.

I´m looking for a Najda DSP in version 1.3. Ready built or the pcb/parts.

Hey guys, I need advice on how to measure accurately, to match some 10nF caps. This is for a phono stage project.

My Fluke 87 (in relative mode) let me down, or so I think it has. Every day I measure the values go up and down a little -- inconsistent. Is it temperature related or what?

Should I use another method -- the freq. generator with resistance? If so, I need need to purchase one. Anyone try the ones on Amazon ~$90usd? Are they ok?
What to do? Should I better invest in a scope?

thanks!

Is there a way to check whether the midwoofer and the tweeter of a two-way speaker are in phase (soldered correctly) without disassembling the speaker?

in the cropssover it seems very few, but many use inductances.
do you have any experience ?

Has anyone "successfully" implemented a crossover for the ZD5 using a Minidsp?
If so, would you care to share settings?
I picked up one SS 15W cheaply, and since I already have pair of XT25s and a 2x4 minidsp, I thought I would play around with this design. Already built one sealed enclosure for test purposes.
Cheers
Peter

The question about the fan volume was triggered by a thread where a MW SPV-300-48 was really annoying due to a constantly running fan that was clearly audible during operation. The solution was to retrofit a 45 Ohm resistor to reduce the volume in the long run. https://www.diyaudio.com/forums/class-d/287470-tpa3255-diy-discussion-design-etc-91.html#post5573119

However, due to the modification, there is of course no guarantee in case of technical problems. I have therefore ruled out the MW SPV-300-48.

I'm currently thinking about whether I should use an LRS-350-36 or HLG-320H-36A. Of course, the LRS-350-36 is cheaper, but the main differences are the cooling system and the efficiency. The prices for Germany include 19% VAT. The prices in $ are without VAT.

I am particularly interested in the LRS-350-36. According to the technical data, the fan of the LRS only starts to run at a temperature of 40 degrees Celsius.

What are the experiences in practice regarding the noise level of the fans with MW?

Posters,
Can you help me please?
I have built a new arm and would like to measure its output, and see what i might improve.
Helpful posters have suggested a new external soundcard and using REW on my PC. i might do that with their help in the future.
However,
I have used REW for my speakers and was comfortable with that, but might i start using the soundcard in my PC?
PC is microsoft surface book laptop, just a few years old, i have the add on dock with its ports. i have no idea what it has or can do............!
Can i take the output successfully from my Graham Slee reflex C into the PC and REW?
Advice most welcome, thanks
Mike

Hi all,

I have this 5 channel amplifier, it doesn't power on, stuck in protect. All psu fets are not shorted. it has 2 ics, not sure how I can test or identify these. one of the ic's has a discoloration.

This amp uses FESF8DT for the rectifiers.

Are the BYW29 the same as the Fesf8dt?

First of all... I am new to this. If I say something silly, just let me know. I am doing this to learn and I am not afraid to fail. So here we go...

I am building a dual mono-block amplifier with a pre-amp. All in one case, but planning to divide every board with 2mm of aluminum to reduce any potential noise. (if this is not necessary, please explain).

These are my parts:

2x IRS2092 class D amps - max. 200W / max. 50V / max. 8A
1x AD827JN pre-amp - max. 15V / max. 2A
1x powersupply DC - max. 600W / max. 60V / max. 10A

My question is: I would need an extra regulator for the pre-amp, right? Because I cannot connect the amp AND pre-amp because the pre-amp can not handle the power that would be coming in.

Any other comments are welcome. Positive and negative ones.

Cheers.

EDIT: If people want to know what parts I am using just type the modelcode in AliExpress.

I need low-current voltage regulated supply for a tube preamp/driver circuit.

Kicker is I need voltages in the +- 100 to 200 voltage range, and I want to use my existing power transformer that only has 400-0-400 CT output. Maybe I'm dreaming.

Anyway, I already have nice high-voltage current source devices, the IZCP10M45S. Is the a decent, simple way to use current sources for voltage regulation?

Does the standard rule of thumb for plate load resistors (~2x the plate resistance) still hold true when using a CCS tail?

I ask the question as most of the reading I've done tends to gloss over on the exact details of designing a LTP with a CCS. Most writers say to use one for best balance between outputs, but then proceed to explain how to design one for a guitar amp using a smallish tail resistor.

I've got one on my bench that is working fine, but the values of my plate loads were arrived by looking at other designs and a little trial and error rather than a general understanding of the theory.

I am considering an E55L parafeed spud amplifier later this year. I've been doing this tube DIY thing for a little over a year now, want to see if I am overlooking anything and get some feedback.

Here is the draft schematic and then some commentary. Note that some part values are stand-ins.



Rather than a plate choke, I would use a cascode CCS load on the E55L. I have a spare Sowter 325VAC 161mA mains transformer with the appropriate voltage to cover the full peak-to-peak E55L plate swing and headroom of the CCS.

I would like to use a 1:2 SUT on the input to reach full output of the E55L with a 2Vrms input.

My mains transformer has three 6.3VAC secondaries. I was thinking of using a voltage doubler on one and going fixed bias since the E55L will only need around -7V on the grid.

The other two 6.3VAC secondaries would be used for the E55L heaters and a tube rectifier.

For the power supply, had thought to use 5V4G or GZ37 for soft start. The Vdrop of the rectifier will help chop off some excess voltage and spare the CCS some heat. Given the PSRR of the CCS, a simple passive CLC supply could be used.

For output transformers, I have swapped emails with Jack and Electra-Print a few times, would like to try his stuff out. I had thought to order a pair of multi-tap 2.5K parafeed transformers with 8, 32, 120, and 300ohm secondaries. This amplifier could do around 2W into 8ohms, so good for a flea-watt speaker setup and gobs of power for headphones.

Thanks for your input 😀

Hello,

Are there any circuits for stereo to 2.1 method ? I cannot find or searching it wrong. I'd like to have circuit which do this. Stereo signal IN, put two potentiometeres one for the stereo control one for the .1 sub. The best would be a cricuit with a low pass filter for the .1 part.

Thanks

I'm planning to build an enclosure with the following things in it:

- Power entry module (PEM) with fusing and internal EMI filter
- Ground loop breaker (GLB) consisting of bridge rectifier, resistor(s), capacitor
- Connex SMPS800RS with +48 VDC and 0 VDC outputs (the 0 VDC output appears to be isolated from input power ground although I'm not 100% sure)
- Some sort of +7.5 VDC SMPS whose 0 VDC output is fully isolated from ground
- 2x TPA3255EVM and 2x some other TPA3255 amp boards for 8 amp channels altogether, which have plated mounting holes connected to their incoming power ground/common
- freeDSP Aurora which has plated mounting holes connected to its incoming power ground/common

Diagram to follow, but essentially the way it will be connected is as follows:

- Mains power from the PEM is connected to both power supplies. The mains ground is tied to chassis using a grounding bolt (the metal body of the PEM is also contacting the chassis directly)
- The GLB is fed from the grounding bolt and has "output" tied to the SMPS800RS input power ground and USB connector/cable ground
- The amp boards are fed from the SMPS800RS outputs.
- The power for the Aurora is from the +7.5 VDC SMPS outputs.
- The audio input for the Aurora is via USB connector from a PC.
- The Aurora will transmit audio out via balanced outputs to all 8 amp channels, probably (small chance of single-ended connections)
- The mounting holes of all amp boards and Aurora are isolated from chassis (i.e. not connected to ground).
- The only conductors electrically bonded to chassis are:
-- Incoming mains ground
-- Grounding bolt for safety - which feeds the input of the GLB
- All wiring is contained within the enclosure, with the exception of mains power cable, USB cable, and speaker cables

Some questions:

1) Will I have a ground loop between the two power supplies, or their downstream devices, because neither of their outputs are referenced to ground? Again, not 100% sure that the SMPS800RS output is fully isolated from ground but I get what seems to be an open connection when I try to check resistance between 0 VDC output (marked "GND", surprisingly, on the PCB) and the input ground terminal.

2) From a ground loop standpoint, does it matter if the audio output from the Aurora is single-ended or balanced to the amp boards?

3) Should I bond the mounting hole(s), or some other connection/terminal/reference intended to be grounded, of the amp boards to the output of the GLB so that the amps don't float?

4) Should I bond the mounting hole(s), or some other connection/terminal/reference intended to be grounded, of the Aurora to the output of the GLB? The USB connection prevents the Aurora from floating, I think.

5) What else should I do to mitigate ground loops in this fully-self-enclosed system?

Hello I am new here. I am not sure if I am posting this in the right place.
I have a Sherbourn 5 channel amp. The relays have started to give me problems. I went on the web to try and find replacements but cant find the same ones. My amp uses 15 amps relay and I found ones that are only 10 amps. Do you think these relays could work? I have included pictures of both relays. The first one is from my amp, the second one are the ones I found on ebay.

Hi everybody,

looking for advice from someone which has more experience with guitar amplifiers (diffent manufacturer build approaches and motivations like in hifi).

In general the noise floor is higher, some buzz hum/level is normal (various guitar pickups, sensitive speakers, chassis shielding standards are lower = the top cover is often wood frame).

The particular amplifier I am trying to fix (solid state Marshall 5275 from 80's) is humming/buzzing more like my previous guitar amplifiers so I am still not 100 percent sure it is normal, but I have found numerous mentions that Marshalls from that era are noisy and they did not bother with hum because it does not matter at band level volume.

This unit is freshly after service where all the usual culprits where handled:

- cracked solder joints checked
- all potentiometers cleaned
- bolts are chacked and fastened
- pcb connections to chassis, checked and cleaned
- input, foot switch, effects loop, external cabinet jack sockets are cleaned
- all electrolytic caps replaced
- all coupling tantualum caps replaced (with bipolar electrolytics)
- preamp power supply zeners replaced
- main rectifier bridge replaced
- factory mods and differences between schematic and amp were reviewed
- opamps were checked and put into socket
- infamous channel switching IC CA3046 was checked

The hum buzz level is exactly like it was before the service. I have measured it with REW on idle via headphones output. Attaching it together with schematics.

The most dominant hum frequencies are basic 50Hz and 3rd harmonic 150Hz.

Transformer itself has mechanical hum and there is also full size spring reverb tank at the bottom.

Any ideas and hints are welcomed.

Thank you.

I would like information on how I could amplify the low level signal from a tape playback head. I realize that I could take an existing player apart however the amount of mechanical parts used to operate the player would probably over complicate things for my purpose. Is a preamp necessary or could one go directly to an amplifier? I do not need audiophile quality. What are the various leads off the back of the head for. Some have two and others have four.

Thanks in advance for any input.

Jason

Here before ebay and others,
A long over due clear out of my amp collection I've built up over the past few years and sadly this one is another which has to go. The superb DIYaudio Pass ACA 4watt amp.











It has been upgraded with various tweaks (premium parts) as kindly outlined and posted by TungstenAudio, well worth the extra effort.

£225 + shipping at cost or collection by arrangement..

TIA

My Maplin Millenium clone didn't work so I'm going to salvage the expensive components for this Williamson 5-20.

It uses an E-Bay PCB from R-Sound.

I'm salvaging the following components:-

4 x EL34, 2 x EF86, 2 x ECC83

2 x Hammond 1650H 6.6K OPTs

240V / 350V 250VA transformer (actually 2 transformers working together)
240V / 6V 50VA transformer

The B+ might be a bit high. I'm aiming to reduce it with a CRC arrangement. Solid State rectification into 220uF then 200R followed by 600uF.

So my kids are now at an age where hopefully they will stop prodding speaker cones therefore I've dug out my gk1 and aksa 55N.

Hugh was already gracious enough to forward me all the old paperwork I had misplaced and I have somehow got the remote working.

Next issue is the sub outputs appear dead.

When I connect the subwoofer to the regular pre-outs, it works fine. Before I dig out Allen keys to open the case can anyone provide advice on where I should start looking for the issue.

Thanks all and hope all you wonderful people are doing well.

Help me I need MAB8441PT164 DataSheets🙂 🙂 🙂 🙂 🙂

Hello, I open this thread to get help in improving my current DIY subwofer.

Currently, I have ATS Loudspeakers. Jenzen-ATS

To reinforce the lowest frequencies I use a pair of subwofers in mono (connected in parallel, since the impedance of the subs is 8 omh and the Hypex works at 4 omh) amplified with a Hypex DS 4.0 amplification module.

I use the Perless SLS 12 in a sealed box of about 87 liters.

The perless ones work well but they are not real subs. I must use the eq to reinforce the lowest frequencies. My intention is to "fill out" the frequencies that are not capable of reproducing ATS (below 50Hz)

My question is the following: can anyone recommend subwofers of 12" for sealed box that can reproduce better than the Perless SLS 12? if possible, with a "reasonable" price.


BR


Toni

Im currently building a sub box with a 189SC (stroker) in it.
Does anyone have any experience with these drivers.
I have a box volume of net volume 210 litre and planned for 2 four inch tubes but the length is not defined yet.
Maybe need 3 tubes?
Data on element is
Fs 22.5
Qts 0.145
Vas 280.
Xmax about 9 mm.

Anyone who want to start a ritual debate about what is recommended ? 🙂

/Mikael

Hi all. I have a Kenwood KT-45 Tuner that seems to not power up. Does anyone have a service manual for it or schematic? Where can I find info to help me fix the tuner?

Thanks

I've been building DIY speakers for quite a few years and I think DIY speakers can be fairly competitive against commercial speakers, within some limits. As the price gets higher to about 40K a pair, I think DIY may not have the resource to compete because commercial can have better access to cabinet materials that DIYers can't. For high-end, cabinets are just as important as xover or drivers.

For preamp, can a DIY compete with say a Conrad Johnson ART preamp? I have to admit commercial preamps can be pretty expensive. When you look inside them, there are not that much that can cost too much money.

Hello to all,
any users of the Khadas Tone Board in this forum?
It measures very well and i own the standalone version of it,
which is called "Generic". Great sound!

Review and Measurements of WesionTEK Khadas Tone Board DAC | Audio Science Review (ASR) Forum

The "Generic" version is powerd by USB an receives the signal through SPDIF. No USB input.
The VIM Edition is controllable via PC and allows USB, SPDIF In/Out and much more.

I have one problem with the Generic version:

As far as I understand the description, alternate connecting should be possible via the 40-pin FPC socket.

Khadas Tone Board User Manual | Khadas Docs

I.e. pin 13 on the FPC socket receives SPDIF, and pins 1&2 receive 5V

But using a voltmeter I do not measure any physical connection
between the SPDIF Jack and FPC pin 13 or the USB-Voltage input and FPC pins 1&2.
Does anyone know why?

All the best,
Salar

Hello,

I bought 2 PCB to build 2 pa150 boards (see attached picture)

Every component comes from Mouser

Resistors for gain are 0,6W 0,1% 20kR and 1kR

47pF have been replaced by 8pF

Only one side is filled with 2 caps Panasonic 2200uF

22uF // 1uF are soldered directly at the rear pins of the 2 rails of the 3 LM3886

Thiele network have been added - soldered on the side of the speaker connector (not on PCB side)

The 3 pots has been well adjusted

10uf has been put for the input cap

PSU with toroid transformer 2x25V with secondaries decoupled with 100nF, 2 bridge rectifiers KBPC5010, 4x 22000uf caps, 2 5,6kR bleeding resistors.

I thought it was a pretty perfect setup, but no🙁. When there is no source connected to one PA150, it starts to oscillate - and I cannot know why 😕

Help !!!!

Many thanks,

Guillaume

I have a hybrid Vincent monoblock that is having an odd problem. When listening the woofer moves in and out slowly on one of the monoblocks. I haven't noticed any distortion though. I have tried a digital source after thinking it was a resonance issue with my turntable. I swapped channels on my preamp, interconnect cables, speakers and speaker cables. This is the amplifier causing the issue. Has anyone ever seen this? Where do I start?

Thank you in advance,
Scott

I was experimenting with a new "office" size 2-way. I posted earlier in the MR16 Satori...

I am really impressed here with these inexpensive drivers and felt I should start a new thread to share.

I bought drivers on sale but even at full asking price these are a steal for the performance to price ratio. I spent less than $100 US on the mid woofers and tweeters (all 4!). I had plenty of boxes and crossover parts so here we go...

Mid woofer is the newer SB budget 13PFC

SB, SB13PFCR25-08 - Meniscus Audio

This has the round frame or basket as opposed to the original design with the odd shaped frame. The OEM FR shows that some improvements were incorporated into this newer version.

The tweeter is a "Vifa" silk dome with FerroFluid, large magnet

Vifa DX25TG59-04 1" Fabric Dome Tweeter

I have these in a closed box about 6 liters to start; I think a slightly larger box would help the bass; maybe 8 to 12 liters??? On some recordings, the bass can be just a little boomy even with stuffing/fill of 75%. You guys with good sims software could try this out maybe for those of us not having these tools.

I am using a basic 1st order LP and HP. I won't share my exact X/O here but most of you wouldn't do it my way so no loss really. If you would like more details on my X/O, PM me and I'll talk about it more.

These things are amazingly good for the money spent; I would encourage anyone thinking of a smallish budget system to have a closer look.

I will say I am using a Goertz flat foil inductor, 16 AWG on the M/W and a ClarityCap CSA cap. on the tweeter. The attentuator for the tweeter is Zisters resistors. These X/O components aren't really budget but I tried other lesser caps, coils, resistors here FIRST. I went to the higher quality and will stick with these; the increase in resolution, detail, etc. is certainly worth a few extra dollars spent on X/O components. These drivers; although budget, deserve a decent X/O design; the results are well worth it for sure!

So it’s been an easy week in school so I decided to try my dad’s corner horns he built 50 years ago. After moving a couple wires around to what would make most sense, I managed to get them working. Only problem is, they sound bad! I’m just a high school kid but i'm guessing it’s from the old wiring and crossover components. Since you guys will know best, how should I approach the renewal of these beautiful speakers? Recommendations on new, quality parts?

SOLD

When will the M2x Pcb`s be back in stock?

I looked at buying typical ceiling speakers for a good while and finally decided I'd like to build some much better. Mainly because I don't want downward facing speakers. I'm making two for my living room and one for the kitchen that's parallel with no wall between. Currently have no system since moving in and TV speakers have finally drawn me mad. For now these will be the only speakers in this setup. The old lady believes in walls next to TV/fireplace will look bad..Hopefully can change that and eventually turn these into atmos speakers possibly. I have yet to see a 3 channel atmos speaker however. Still worried about how it will sound for now, but I'll take stereo over TV speakers any day.

TLDR: First crossover/speaker design looking for feedback to improve now before building. Parts have all been bought, but can still be returned. Powered by my Denon AVR-X2200W. Still debating two versions of my LR speakers and looking for suggestions.

Still have yet to figure out speaker grills, but here's my main questions.

1) Should I make these boxes taller/shorter? I have room to make then 20" tall
2) Do crossovers look decent on paper? Can I improve any? Not too sure on the kitchen design with the two 4" drivers.
3) Still debating on porting them? Any suggestions? If so would it be best to port into the room or into attic?
4) LR v4 or v5?
5) Polyfill them? Or just do one and then decide?

2 Ceiling speakers in living room on axis 8ft from TV and another 8ft to LP
Dayton Audio ES140TiA-8 5-1/2"
Dayton Audio RS225-8 8" Reference Woofer
Dayton Audio DC25T-8 1" Titanium Dome Tweeter

Version 4




V5



X/O



Kitchen




X/O

Hello all, I recently installed VituixCAD and it seems really great! Powerful, fast, etc. Except I started by copying a design I was working on in XSim and I noticed the SPL/filter transfer function was very different between the two programs and I can't seem to figure out why. So I typed it into PCD7 and it agrees very closely with XSim. Anyone else experience this? I would love to make Vituix my go-to program, but I gotta figure this out first. See files and screenshots below.

Before you ask, yes, I messed with the offsets, minimum phase, generator settings, none of it comes close to making it match. I've got to be missing a setting in Vituix somewhere. THANKS!

Does anyone have some spare PCB's for the 'current amp' (ultiamp) that was published in 1992.

Does anyone have a source for ready-to-use CCS modules, or at least bare boards? I need 1-20mA and at least 400V, 2-wire devices. Prefer DN and/or IXYS cascode, but any good circuit will do.

Hi
Everybody, I'm working on a Input and also Driver stage on a new Design for a Class A Amplifier.

The Point is this input is already build and it is running almost perfect.
Now nothing seems to be perfect,sometimes. as you will see..

I'm trying to increase the upper Frequency range of that Stage. This consists of 3 Transistors. It can be two as well, but if I use only two then I lose gain.
If I use three then Bandwidth will not Exceed 100Khz much. And output of Square Wave and also Sine wave will be Distorted, up to 1% comparing to 1Khz. The Circuit I have uploaded before already but I will upload it again, when I have Commented what has happen last night, in the circuit.

Now, this amplifier again with Output connected is build and it runs, but for my understanding there could be more. and has been tested already, and it sounds great, but I'm not finished with it yet.

Last night while testing and preparing the PCB, By accident, I reversed somehow the BASE and EMITTER Pins, of the first Drive Transistor. Put on my desk, plugged in my Test Equipment and tested just the output of the second Drive Transistor. This I tested OPEN LOOP, so none Negative Feedback as well Output Transistors weren't connected yet, and applied Power.

At that Time, this was last night, I didn't knew that I Reversed that Transistor, and started with 1KHz Sine Wave, and pulled up the Gain control on the Function Generator and measured Output on the Collector of the Second Drive Transistor with 25.6 Volt RMS! See Pic 10..

WOW!!! Why, what happen.??? I was stunned about that, so I viewed and controlled the RAIL VOLTAGES and there I thought I saw why, 48Volts, + and 48Volts -.
Oh, yes, of course, output Transistor hadn't been connected yet, OK clear.
So I connected a Load which would Simulate the Output Transistor to 70% and checked the Voltage again. DC V+- read both 43Volts sometimes only 42.9 but equal.

OK. Measured again the Sine and Square Wave of 1khz, still 20.8Volts output before the sine wave would really clip.
Switching the Frequency to 100KHz, again WOW, Clear as the 1KHZ Wave.
Turned Frequency up to 530KHZ till the output would drop down to 16Volts RMS. But no Clipping.

Slowly turned the function Gen backwards, and finally @300K there distortion was gone, and the full 20.0 Volts same as 1Khz where a there.
Now, it was still unbelievable. So I took a 1Kohm resistor and soldered this from Collector to GND.

Now some changes happened. But still 20Volts RMS output at the collector of the Second Drive Transistor. So, lowered that 1K to 600 Ohms and I still got 17Volts output.

So I was very pleased and measured Noise, and Hum and DCV out and all was better that I thought it would be.

So, I decided to stop working on it, as it was already late night, and today I went back and checked everything because I thought I would connect the Power Transistors and the screwing the board on to the Heat sink. While getting the Drive Transistor in position to screw them onto the HEAT SINK, I saw something strange. The first Drive transistor had no number printed on front of it, or better say LABEL. I use BD139-10. this one are all PLASTIC.

So I took a multiplying lens and checked for the LABEL. and because of these two Transistors, are just besides each other I noticed that the thickness of the left one didn't match the right one, and then I looked at the backside of the left transistor, and there was the label. But hey, the amp was just running fine.

Connected the Amp again and tested again. same as last night exactly. just beautiful. Removed the Wires, dis-soldered that Transistor and used my TR TESTER to check HFE Gain, and it was I noted it down the other day when I made Selection of the Transistors. And one more thing was curious. Usually I need to get some small Capacitors soldered on BC to reduce parasitic noise, just a few Picofarad usually not larger than 33PF. but on this Board, I did not need any.

Of course, last night I took Pictures of the Scope and the measurements.
Then I saw in the pictures that the Transistor was running out of Phase by 180 Degrees, and this on all Frequencies.
So today, I soldered it back into the PCB, but this time the right way.
Set up my Instruments and tuned to 1KHZ sine Wave 50% output. first thing I saw, was lots of Parasitic Noise, two small Capacitors together 33 and 22 Pico and the wave was just as beautiful as last night.

I do always search for the max, so Pictures are taken @20.8 volt, where the Wave starts to clip. Sine 500K is 16Volts RMS, still within 2db without clip.

But the follow up was not that nice anymore. 1Khz to 50KHz 20Volts RMS before Clipping, with shunt resistor of 1KOhm to GND.

Above that just Catastrophic. 100KHZ -1db 120 - 2db no way to get higher than 150K would output only 16Volts RMS. Still good but not to compare with last night.

The BD139-10 pin layout is 1= Emitter 2= Collector 3= Base if seen from front where the label is printed. I soldered it with the label to the back, this would mean that E & B were reversed. So how the AMP POSSIBLE COULD work and WORK BETTER THAN when connected the RIGHT WAY.
Has anyone see something similar to this,??
Of course I have pics and I also will place the Circuit. But what you would say just out of the blue has happen. I tried to simulate that today on my computer, yea I could simulate it but with lost of distortion measured in the simulator software, but in real-time there wasn't any distortion.

Does anyone has an Idea,? Shall i put the Transistor the wrong way in to get better number? And after all the world would laugh at me, what a fool..

Thanks for any Input
Regards

Chris Hess

Look at the pics from Last night first. these from today
I will place later..

Are theses the correct fets? I’m ordering 10 of each to replace them all? And do you think I need to replace the the mur 1540 I believe? Thanks!

I recently compared an old AB power amp (so old it had a single 75V rail supply and all NPN Outputs. I compared it with a tpa3118 (60w) and although not a fair comparison in power rating (the AB amp is about 120w), the old AB sounded a lot more polished and alive. I didn't mind the class D until I "AB-d" them with the same pres (one tube pre and one discrete SS). Maybe class D just can't sound as good? Maybe it was the extra watts in the AB amp?

Bob Pease sadly killed reportedly returning from Jim Willam's memorial

Two of the “Greats” in Analogue electronics have died recently.

Ironically I’ve was presented a book by Bob Pease on safe driving – with a picture of his VW Beatle on the front cover 🙁

"Word has just filtered through Twitter that Bob Pease was killed in a car accident.

This one by the sounds of it:

Driver, 70, dies in Saratoga crash - San Jose Mercury News

In a sad twist of fate, it is reported that he was returning from Jim Willam's memorial.

A very sad week indeed."

RIP Bob Pease & Jim Willam's- Thank you both for your contributions to the art of analogue electronics!

biamp boards are starting to fail - probably the "black goop of death".

Do you know of any passive crossover schematics to work decently with this speaker's drivers?

We don't currently have any way to measure response nor impedance of the drivers.

A good guess might do.

Completely in the dark here, what might it be called? I don't want a computer, just a portable type player that plugs into the wall, with an interface to scroll the filesystem and some RCA outs. Many thanks!

I have a Samson L612M powered monitor to repair -- haven't been able to find the right schematic -- almost given up. I have schematics for the L1212 and the DB500A -- both of these have elements that match up to the L612M, but neither is the right one. The power amp board is silk-screened "DB300A power amp bd" so I assume it shares that board with the DB300A -- BUT, I can only find the DB500A schematic, not the 300. The L612M has a TDA7294 monolithic 100W IC power amplifier -- this is in none of the schematics. Thanks for any ideas about where to find the schematic.

Also must say that this unit is designed in a very screwy way and is not repair friendly at all, woof.

Stereophile Class A recommended components..

**** TU8600S with interstage transformer **** sorry for the typo.


Hello,

I am another fan of TU8600S and I toyed with this wonderful amp and I thought what I did may be of interest to some.

In short, I put the para-feed interstage before 300B without changing any given circuit except not using the C104 and C204.

A Fantastic fact about TU8600S is that it has these TP points that make my experiment really easy.

What I did ;

- remove C104 C204 or just cut the PCB path (in the picture)
- Use four TPs to connect the 'cap + para feed interstage transformer' (in the hand-drawn circuit..)
- I used Ludahl LL1635PP. You can use whatever 1:1 interstage. I used PP version because it has no air gap which is an advantage.
- give it some time and listen to it.
- If you don't like it you can put it back to the stock state 100%.
- If you like it move the OPTs(stock version) to the backside a little and fix the LL1635
- I used in-line connectors to compare with the original sound later. 🙂
- beware of the phase of primary and secondary, wrong connection causes oscillation interacting with cathode feedback winding of output transformer.

I was pleased to know that this mod does not change any nice appearance of TU8600S.
About the sound, well I like it but who knows about the taste of who except oneself. As a DIYer, I was once shocked by TU8600S performance and tried to improve my 2A3 SET for some different charm that can be used occasionally with TU8600S.
I can say that my TU8600S has that nice tone of 2A3 now and I am listening to more music. 🙂

Cheers,
Chul

hi,
I'm planning to upgrade my DAC with crystek 967 oscillator and its datasheet doesn't provide anything about proper implementation of it.
it does say Load Capacitance 15pf, I would assume that a 15pf capacitor to ground should be placed on the output line (pin 3)
and should any resistor in series be placed as well?
the data-sheet is very poor,
any suggestions are welcome.
thank you.

The deck powers on and radio works

Tape player doesn’t work at all I bet no response from the unit .

It won’t play tapes won’t fast forward wound rewind won’t eject .

Could this be from bad solder connections or bad caps or does this sound like a different issue ?

Any thoughts ?

Hi!

Atached is a psu schematic, based on LM317/337 regulators. I expect to draw around +/- 400ma from the +/- 17v rails (LM317/337). Nothing fancy, quite normal circuit.

But my question is about the part of the circuit i signaled within a square: These are two additional positive rails derived from an RC filter after the positive side of the diode bridge. So, from the diode bridge there is an RC filter 10R/1000uf, and then two LM78xx linear regulators.

I have to say that i don't expect to draw much current from these two additional rails, as they are to supply current to six 24v relays (2880R coils), and two lamps within round vumeters, that i will supply with 8v.

My question is just if the arrangement in the circuit signaled within the square is ok.

Thank you for your advise!!

Jay x

Hello everybody. They gave me a Pro-Ject Phono box S2 phono pre that has two JRC 2068 op. amps inside, on my old Cambridge preamp I remember replacing these opamps with BurrBrowns, do you think it is possible to do the same thing? I have heard good things about the new OPA1656ID which have high gain and very low distortion. I ask someone who maybe has already made this mod or knows a lot more than me. Thanks again.

HI, I have a Marantz PM6004 amp which has developed a problem. It was working fine until I went away and turned it off for a few days, when i switched it back on things went wrong.
The output through the speakers was now at a low volume and heavily distorted, i checked the headphones and the output was the same. I checked the input and discovered that the input from the CD could also be heard at a lower volume when changing the input selector to any of the other inputs, i.e. I could hear the CD through the AUX input. I changed the input to say the Phono input and could hear that through all the other inputs.
I thought it may be the input selector chip at fault but couldn't find any shorts across the pins.
Any suggestions as to what to check next?

Hi all,

I am putting together parts for a EL84 SE valve amp build - what’s the view on paying extra for matched capacitors and resistors ?

Is it worth paying extra, does it make a difference , is less or more necessary for a single ended build ?

I have read somewhere it’s not worth paying the extra as the matched pairs don’t remain matched for long once the equip is being used and so is a waist of money.

Thanks

As the film title says, “Never say never”.
So perhaps I should not have used the word last attempt.

Anyhow, a DC-stable discrete opamp in a DIP-8 Footprint has remained unfinished business for me, despite a few attempts over the years.
The previous failures were largely due to DC offsets and unity-gain stability.

In the last 18 months, after much contemplation, a renewed effort was made to take on this challenge one last time.
This time with much better success, apparently.
Nothing really ground breaking. But that is also not where the difficulty lies.


Patrick

.

hello fellow HI-FI enthusiasts

after upgrading my rc-971 as per this guide --http://whatishifi.blogspot.com/2017/04/modifing-rotel-rc-970bx-and-op-amp-comparisons.html

i did not upgrade to a stepped attenuator, but did replace all of the power circuit caps.
in the signal path i used panasonic fc 25v 1000uf
would the attenuator make a noticeable difference ?
also in the future i intend to add a subwoofer output.

any suggestions are welcome

thanks for reading
gaz

ps couldnt upload schematic because "file to big" and cant take a screen shot on this computer. maybe the forum should have a repository ! i have some i could share.

I have observed that in tube electronics different B+ volages are set by resistor networks, followed by capacitors, for each voltage.

I have a solid state preamp that requires +23@135mA, +5.6V@95mA and -12V@9mV.

How bad would it be if I have a stiff 35VDC power supply with a resistor network, consuming 0.5 - 1A and tap it to get the voltages I need?

This maybe an obvious solution. I am asking because I never see it used in solid state projects.

Thank you.

Teen Wall Speaker 59$

Some 5 years ago Audiovideo.fi designed these Teen Wall Speakers. They were ment to match cheap price and quality sound for teenage kids. Price was about 59$. The drivers were from big stock of leftovers.

Kaiutinrakennusohje Teini-seinakaiutin ja Teinijytky-aktiivisubwoofer - AudioVideo

Bassdrivers: Nokia Harman LPT 145/25/100FS
Tweeter: Nokia Harman LPKH 50/10/100 SKF

Now it seems that the big stock has been consumed and I can't advance in my project to build pair of these. Actually the tweeter is missing. Any help to replace it?

The parts came from Kaiutinelementit - Hifitalo

Edit: parts came available and I used those. Teenage Wall Speaker 50$

What is the livingston tonearm?Well done or poorly done?What does it sound like?