diyAudio

D132 · 2024-01-17 3:35 am

Hello! I'm new to the forum and I'm hoping someone may be able to help me. I have been trying car audio amp repair but I'm lost at the moment.
I have 2 Monoblocks with different issues.

1. Concrete Audio 2k
Protect mode at 13v+ although rated up to 16v
At 12v, gain all the way down, no input, and with a speaker connected (I have tried a few different speakers and all do the same), starts normally then makes a loud pop every 3-4 seconds and flashes protect light
Does not happen with nothing connected (12v), audible click, power light and fans running, no protect

2. Soundstream XXX-6500D
Turns on with power LED and no protect, fans run, but no output to speaker terminals
Tried multiple speakers, tested with multimeter (any settings to try? I may not have tried correct setting), multiple RCAs, but only tested with 12v. This specific one has ratings at 13.5v, 14.4, and 16v but my other XXX-6500D has at 12v-16v.
Would 12v vs 13.5v cause this?

As of right now I would prefer to get the Soundstream working sooner than the Concrete Audio amp as I would like to install the Soundstream in my setup

I have a variable power supply that can go up to 30v and 3amps, a component tester, multimeter, and an oscilloscope but I am a bit confused on where to probe, what settings I should have, and where I should ground the probe or if I shouldn't use the ground lead.

Any help is appreciated and if there is anything someone would like me to send pictures of I can do so.

RayD8r · 2024-10-04 12:21 am

I posted in another thread but it's concerning a different issue and didn't get a response so I'll give it a go here. I have a pretty clean Onkyo TX-8211 receiver. There are 4 speaker outputs, A + B - L & R. BL doesn't output any signal to the speaker upon powering on the receiver until the volume is turned up to around 2/3 to 1/2 volume, which is quite loud. Get me into trouble with the building manager loud. Once it kicks on though, it will remain working, even at low volume for as long as I keep the unit powered on, even if the music stops and starts again. Once I shut the power to the receiver off though, it's right back to not working. I removed the main board from the chassis and looked it over thoroughly with a loupe because there were traces of what looked to be solder and possibly very fine silver wire which initially made me think that a jumper or other component had violently exploded but after examining the board for a solid half hour, top and bottom, close up I couldn't find even the smallest evidence of anything out of place and I would think that any kind of damage that would produce little shards of metal would be at least somehow visible somewhere on the board so I've ruled that out for the most part. There's no burn marks or any discoloration anywhere nor any solder points that look abnormal, pieces of any components or stubs left where any component would have been. It's actually a pretty nice looking board for it's age. So in reading several things on it all points kind of lead to a speaker protection relay of which there are only 2 on this amp. They are both DG2SU DEC relays. Looking for some input on this issue please...

jcsb · 2024-10-05 1:34 am

So as a retired mechanical engineer I take interest in how the layout and assembly features are handled by different manufacturers. So, I have a Krell 300-s amplifier apart and was really intrigued by how they chose to attach boards and casings. This is my amp and it's the first time I've had it apart. It was in climated controlled storage for about 4-5 years. Set it up and turned it on and no right channel. Reviewing the power supply board and found (2) 5ohm 5watt resistors that were open. Replaced those and was able to start it until it went into action and failed. Removed the output board and the driver board. Found some parts that were cooked from the start up. Fix those and the next time, no right channel.

Starting with the power supply board I found the same 5 ohm 5 watt resistors opened again.
This lead me to disassemble the power supply board with the 68,000 ohm 100v capacitors on it. Two things struck me as really odd. First, the board is not attached to the case. It is in free suspension with only the straps coming from driver board suspending it. Certainly not the way I would do it since it would be susceptible to stress when moving the amp. But the real problem was how the large capacitors were attached. They were attached by only one screw and the other post was allowed to make contact only from the friction of the other screw holding to the board. I had originally thought there was a screw that went though the center of the bridge rectifier that would secure the other post, but no. This is without a doubt the most unusual and potentially dangerous way I can imagine. The first capacitor I removed (once again only one screw holding it) had been arcing off the contact land on the circuit board where there was nothing securely attaching it to the board other than the other post that did have a screw.

I would love to think that this had been worked on before I bought it and they forgot to install the screws for the other post. If someone out there has any information on this I would love to hear from you.

John

Zero Cool · 2024-09-03 12:07 am

does anyone know if Guido Tent is still around? it looks like he hasn't posted here since 2021 I sent him an email some time ago. just curious if he is still active?

aveo5 · 2024-10-06 2:39 am

Hi I have a Sony amp and I want to wire it to a Rockford fosgate punch p1 single voice coil. I made the mistake of assuming it was dvc before purchasing it. I can't run 2 bridged channels to each voice coil if the sub was a dvc.

Does anyone know if there is a way to bridge the 4 channel down to 1 channel to make it run in mono?

gbowling · 2021-02-15 10:54 pm

I have an ancient Fluke 8060a that the display has been out for many years.

I ran across it in the shop the other day. After searching the internet for an LCD display for it for most of the afternoon and coming up empty, I was about to throw it out.

There were some web pages about rewiring the leads and attaching a different LCD display, but it seemed like a lot of work. And I have two other Fluke meters, so no worries.

But before I threw it out, I decided to just take it apart and see if I could see anything obvious. There wasn't anything obvious, it was pretty clean, the board looked ok, there was very little dirt and no residue of any type that I could see.

But just for grins, I decided to clean the contact area on the LCD with alcohol, do the same for the connector side, and put it back together.

To my amazement, when put back together it works perfectly!! The LCD, which had maybe two segments you could read, is now just like brand new!

So long story to say I learned a lesson! Those old LCD displays may not fail as often as they appear. They just lose good contact and need a little cleaning.

gabo

fubar3 · 2024-10-05 7:38 pm

I got TO220 mica and this fragile thermal tape 567-DST-38-1-76X127. Maybe the tape can be divided?
What should I get to fit BD139 SOT-32 / TO126.

aveo5 · 2024-10-06 2:17 am

Hi after recovering from an aneurysm I've d cided to rebuild a car replacing everything I can with newer equipment. I bought a 73 Opel gt and am buying a ford 1.5t dragon motor with a Alfa romeo transaxle for the rear. I'm adding electric ac, pw, pdl, pm, ps. I'm redoing the interior, repainting it and I want to drop in a kickass sound system.

I decided to do the same with my everyday hatchback since I ended up finding 3 Sony amps.

Kmet · 2020-08-18 5:35 am

Hi..

I want to build stereo MPX decoder (adapter) for my Fisher FM-100 tuner. I was looking for some article in old electronics magazines but until now without any luck. If any of you old/new timers have some information where to look for that kind of magazine articles please tell me.

Thanks in advance.

Dubravko

Asterix2k10 · 2024-10-02 4:54 pm

So I get the Audible Illusions Modulus 2c pre amp back. Here’s what he did. Resoldered circuit board completely - cold joints. Repaired volume control. Replaced noisy tubes. Bench tested for 8 hours. I plug it in and I’m getting crackling white noise on the left side. It plays sound, and then I noticed it is microphonic, amplifying the sound of the mute switch when I push it. I’m going to call them tomorrow but it’s disappointing.

teknofosssil · 2020-05-06 10:31 pm

I bought the Booze Hound so called "Deluxe" phono preamp PC boards and matched FETs. This project caught my interest due to its simple circuit, similar in concept to some of NP's circuit philosophy. Unfortunately it will be a bit before I have time to sniff solder flux. Anyway I was just curious if anyone has built it.
Below is the link if anyone wants a look at whats involved. Take a look at their construction manual too. For 99 bucks you receive 10 matched FET's and two nice quality PC boards. You source the R's, C's and case/hardware. If you are constructing a power supply then transformers, diodes and so forth.

Deluxe Phono Preamplifier – Boozhound Laboratories

gerrittube · 2024-10-04 7:02 pm

I discovered today that one of my (new) 6SN7’s from my stock is quite noisy. I changed the tube and it was a huge improvement (> 20 dB).

I read about reconditioning a tube by heating the tube for 24 hours (or more) and of course I can try this.

What are your thoughts on this and what’s your experience?

Regards, Gerrit

kevinkr · 2010-09-27 12:33 am

Having looked at a variety of very crusty Thorens TD-124 threads, none of which really related too directly to my project I have decided to open a new thread.

I have just acquired a fairly clean, and low hour TD-124 MKII with an SME 3009 Series II arm which I am going to restore.

I acquired this from a parent of a friend who lives in Manhattan so you imagine the day I had yesterday driving down and back as a consequence of this TT purchase.

The TT was a built in and does not have a plinth of its own. Every last bit of rubber with the exception of the belt and pulley has deteriorated to the point of needing replacement understandably..

The lubricant in the motor bearings has turned to glue so rather than just clean and reassemble I have decided to install a motor bearing upgrade kit which replaces the tinned bronze bearings with precision machined sintered bronze bearings, new felt pads and all of the hardware required to reinstall the bearing caps on the motor. (Should this prove not to be as good as claimed I will keep the old parts for that eventuality.)

I need to replace the motor mount bushings, the "gummi-muffins" which are the TT mounting bushings, the six pads on the platter, the belt.

I also plan to install a stiffer bearing cap on the main bearing but since this is a late model MKII I plan to retain the original sintered bronze bearings as they aren't worn at all..

I haven't quite decided on the plinth, but I am thinking to start it will be one of the moderately priced ($400 or so) CLD plinths available on eBay.

This unit has the later aluminum platter so I can use my Zu/Denon DL-103 without concern for the issues of magnetic attraction with the earlier iron platter - the down side is the aluminum platter is reputed not to perform quite as well due to somewhat lower overall mass.. The older iron platter apparently somewhat less resonant, not that this platter appears to have an issue.. The other significant difference is the strobe on the platter is 33 rpm only..

Parts in some cases will be sourced from Octave, and in others from a couple of well regarded eBay sellers of TD-124 parts and upgrades.

The arm has already been cleaned up and is complete and in very good condition except that the decoupler will have to be replaced. (They're readily available.) I also plan to install RCA jacks on this arm as I have done on my other.

zycomatique · 2024-10-05 5:30 pm

I d like to have a battery power supply on my amp with a regulated power.
Often this type of PSU is criticized for its lack of Dynamic. The asr emiter Is known to work perfectly with its battery PSU: Is it a regulated one?
Does somebody know such a kind of PSU with very good sound?

jazzboy · 2024-10-05 2:45 pm

Zero Baffle Demo with Live Sax.
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8ntractor · 2024-09-23 5:35 pm

Hi

A few years ago I got a tremendous amount of help from Several members when changing from Seas Magnesium drivers to Nextel drivers due to corrosion. The Cabinets were the small thor and with the great help of this community I was able to get very good results. When I started on the DIY thing I was sceptical and built really fast boxes which I never finished and which were really not very well done so fast forward 13 years and I am building a pair of speakers with the same drivers and crossovers. Using a holey braces from the old Thor but I wanted to move them into the main area of the house from the basement so I am making extra small thor speakers. The speaker will be 43 x 8.75 x 12 or internal dim of 7 1/4 (183)x 10 3/8 (264) 42 (1070) the tweeter is 31 1/4 (795) from the internal base.

My intention is to build a BR speaker I would have prefered a mltl but after spending many many hours on Hornresp I have come to the conclusion that I am not familiar enough with speaker building to get this right. So my question is when I do put the numbers in at 43 liters and 107 length I end up with the attached chart

As I understand it the path is the distance for the center of the tweeter to the center of the port. So setting the path at 70cm I get

I really like the way the small thor sounded. So I would like to replicate as much as possible given the limitation on the size of the speaker and the nextel drivers.

So my questions are if built as a BR speaker will fiber fill take care of the jagged peaks and valleys?
Where is the best place to put the port?

To Run hornresp as a TL - With the holey braces in how do I calculate the S1 S2 S3 ?
Where does the horn start do I measure from the tweeter (mtm) to the top of the box and back down to the bottom?
What effect does the vertical holey brace have? is it a divider or just a brace is my horn length 107 or 142 or 249 ?

I very much appreciate Hornresp and thank you David for creating it.

Here is the listening position FR for the small thors with the nextel drivers after much help from Allen and Lojzek GM and many others they are now in the campfire and the braces are in the new speakers

tonyEE · 2024-10-05 1:42 am

Went to Costco today... Tustin II. The demographics in that place has a LOT of people wont to act with a herd mentality.

No toiler paper.

Crew told me it was due to buyers "stocking up" on account of the Eastern Port strike.

He was shaking his head, me too, at their incredible stupidity. Maybe they think their TP comes from Germany?

Meanwhile trucks and trains and the Western ports are humming along and I believe toilet paper in America is.. "made in America".

The stupidity of people never ceases to amaze me.

What really pisses me off is that we got lots of TP at home. I could have made a killing on Craig's List.

arivel · 2024-10-05 5:48 pm

hello everyone .
is there an acoustic lens to be placed in front of the LF drivers?.
maybe doing this doesn't make sense (in fact they are usually applied to the HF drivers) since the low frequencies propagate in all directions, in this case the lens must concentrate and focus.
i wonder if there is an analogy with the optical lens (convex shape concentrates, concave shape diverges).
if it were possible to focus a portion of SPL i would like to try with karlson and hear what happens.
Thank you

Spikyball · 2024-10-01 9:25 am

Hello, I have a 46cxa1800.1 class D mono amp with a burned output transistor and I cannot figure out what to replace it with, it's labeled T410 BV8316, there are four at locations, q103, q104, q203(damaged), q204. I'm limited in my knowledge and tools, all I have is a multimeter for testing, I did read that it is recommended to replace all of them for a lasting repair.

mason_f8 · 2024-10-05 12:58 pm

Most modern OP-AMPs, even single types, do not have an offset pin, but many older single type OP-AMPs had an adjustable offset.

I was recently surprised to see on TI's website the latest datasheet (revised 2024) for the OPA132 (and also the OPA134) that pins 1 and 8, previously assigned to the offset trim pins, are now NC.

From the old datasheet.

At first I thought it was an error in the datasheet revision, however, but the notes on pins 1 and 5 (which may have meant pins 1 and 8) said
‘Existing layouts for the OPA132 before revision C of this data sheet do not need to be redesigned.’
And when I checked, I found that OPA131 and 130 also had pins 1 and 5 assigned to offset trim pins before, but they are now NC as well.
Even the OPA627, in its moulded package, is now NC, and only TO-99 here retains the trim terminals.

(The OPA604, TL071 and others still have trim terminals as before.)

The ones I own were acquired a long time ago and all can be adjusted by adding trim pots, but does this mean that the newly produced ones cannot be adjusted? Or does it mean that they are still connected internally as before but (as TI) do not recommend offset adjustment there?
Of course the correct offset adjustment should be made at the input, and we are aware that adjustment by a degenerate resistor such as a mirror inside the circuit can exacerbate temperature drift and other.
However, is it really acceptable to make such an essential functional change to these OP-AMPs that have been in use for a long time? I very much doubt it.

justilew · 2024-10-05 5:47 pm

Hello, I am just starrting my journey in diy audio, hoping the wealth of knowledge here point me in the right direction.

mprivitera1 · 2024-09-08 9:14 am

Hi guys, I bought a prehistoric 😀 piece of final amplifier...I found that the (right) channel is much attenuated compared to the left.
The sound comes out without any noise or anything else....but the right one is about -12db attenuated compared to the left one.
Once turned on, the amplifier detects no errors, green light for both channels.
In your opinion are the potentiometers db regulators or protection relays....or something else.
What do you recommend doing...

Thank you

SomeJoe · 2024-09-21 7:02 pm

Hello !

Trying my hand at a single-ended to balanced line driver/buffer. See preliminary block diagram below. Main characteristics and design goals:

Provide the 12dB gain from -10dBV consumer level to "pro" 4dBu
Standard XLR output
Able to drive long cables ( 25 ft max maybe? )
Bipolar complementary push-pull configuration
The cascode input stage's high input impedance allows the source to also drive a regular consumer 47K input in parallel to this circuit
Input stage LTP CCS-biased (Vbe referenced)
Class A output stage (BD139/BD140)
+/-15V regulated power supply (not swown)

I have no clue on half of what I'm doing 😛 Does this seem a proper topology? Any unrealistic design goals, perhaps regarding the long cables? Do I need to include a feedback circuit?

Thanks for any insights,
Joris

kannan_s · 2024-09-30 7:07 pm

Practically unused RTX 6001 Audio Analyzer. Please PM your offer and Please note: no low ball offer. I will not respond to low offers. You can ask if you need more info. No additional software or accessories.

Backel · 2024-10-05 10:31 am

Hello everyone, 🙂

My name is Clément, and I am currently training as a cabinetmaker in France. I am passionate about DIY projects, especially when it comes to building amplifiers and audio systems. My current project is to create a Leslie cabinet inspired by Dürer’s solid, as well as a matching electric guitar. I’m here to learn, exchange ideas, and share with the community.

I apologize in advance if my English isn’t perfect!

Thank you for having me!

TubeHybridMaker · 2024-10-01 11:25 pm

Hello DIY Audio Community,

I'm in the process of designing a stereo hybrid headphone amplifier that leverages the rich tonal qualities of a tube stage combined with the robust performance of solid-state MOSFETs. The goal is to achieve at least 1W per channel into 32Ω headphones and 300mW per channel into 300Ω headphones. I'm seeking your expert insights and suggestions to refine this design.

I'm using KiCad for schematic capture and PCB design, and plan to have the assembled prototype tested by a certified electrician for safety compliance.

---

### Project Overview

The amplifier is intended to deliver at least 1W per channel into 32Ω headphones and 300mW per channel into 300Ω headphones. The design emphasizes simplicity by minimizing components in the signal path to preserve the tube’s sonic character while ensuring reliable performance across various headphone impedances.

---

### Design Specifications

Code:

+----------------------------+----------------------------------------------+
| Specification              | Details                                      |
+----------------------------+----------------------------------------------+
| Amplifier Type             | Hybrid (Tube + MOSFET)                        |
| Tube Used                  | Tung-Sol 12AU7 (Dual Triode)                  |
| MOSFETs Used               | IRLZ44N N-Channel MOSFETs                     |
| Power Output               | ≥1W/channel into 32Ω; ≥300mW/channel into 300Ω |
| Power Supply               | AnTek AS-1T150 Transformer                    |
| PCB Design Software        | KiCad                                         |
| Chassis                    | WHAMMY Case (80mm H x 210mm W x 230mm D)       |
| Volume Control             | Single Blue Velvet 10kΩ Audio-Taper Potentiometer |
| Testing                    | To be conducted by a certified electrician    |
+----------------------------+----------------------------------------------+

---

### Bill of Materials (BOM)

#### 1. Tube Stage Components

Code:

+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| Component                    | Specification                               | Quantity | Description/Notes                           |
+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| 12AU7 Tube                   | Tung-Sol 12AU7 (Dual Triode)                | 1        | High-quality audio tube                     |
| Tube Sockets                 | 5-Pin Ceramic Tube Sockets                  | 2        | One per triode channel                      |
| Cathode Resistor (Rk)        | 100Ω, 1W, Metal Film                        | 1        | Sets baseline cathode bias                  |
| Cathode Bias Potentiometer   | 1kΩ, 1W, Audio-Taper (Blue Velvet)          | 1        | Single potentiometer for both channels      |
| Decoupling Capacitors (Ck)   | 0.1µF, Ceramic                              | 2        | One per channel; stabilizes bias voltage     |
| Grid Resistors               | 1MΩ, Metal Film                             | 2        | Connects RCA inputs to tube grids            |
| Coupling Capacitors          | 10µF, 400V, Film (e.g., Panasonic EEFUE0G101R)| 2        | Blocks DC; allows AC audio signal to pass to MOSFET gates|
| Stability Capacitors         | 100pF, Ceramic                               | 2        | From MOSFET gate to source for high-frequency damping|
+------------------------------+---------------------------------------------+----------+--------------------------------------------+

#### 2. MOSFET Follower Stage Components

Code:

+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| Component                    | Specification                               | Quantity | Description/Notes                           |
+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| IRLZ44N MOSFETs              | N-Channel, Logic-Level                      | 2        | One per channel; consider heatsinks if necessary|
| Gate Resistors               | 10kΩ, 1/4W, Metal Film                      | 2        | One per MOSFET gate for stability            |
| Source Resistors (Rs)        | 1.7Ω, 10W, Wirewound                         | 2        | Handles current buffering; ensures low impedance output|
| Output Capacitors            | 100µF, 50V, Film (e.g., Nichicon UFW100C)    | 2        | DC blocking at headphone outputs; non-polarized film capacitors|
| Heatsinks for MOSFETs        | Suitable for IRLZ44N (e.g., Velleman AN20)    | 2        | Ensure proper thermal management             |
+------------------------------+---------------------------------------------+----------+--------------------------------------------+

#### 3. Power Supply Components

##### A. High-Voltage B+ Supply

Code:

+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| Component                    | Specification                               | Quantity | Description/Notes                           |
+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| Transformer                  | AnTek AS-1T150                               | 1        | Provides 150V AC @ 0.33A and 6.3V AC @ 3A  |
| Rectifier Diodes             | 1N4007                                      | 4        | Full-wave bridge rectifier for B+ supply    |
| Filter Capacitors            | 220µF, 250V, Electrolytic (e.g., Nichicon UG2J221MPD) | 2 | Smoothes B+ DC supply                       |
+------------------------------+---------------------------------------------+----------+--------------------------------------------+

##### B. MOSFET Supply (Voltage Doubler)

Code:

+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| Component                    | Specification                               | Quantity | Description/Notes                           |
+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| Schottky Diodes              | 1N5819                                      | 2        | Voltage doubler configuration; low forward voltage drop|
| Electrolytic Capacitors      | 1000µF, 25V, Electrolytic (e.g., Panasonic EEU-FC1C100) | 2 | Filter capacitors for voltage doubler         |
+------------------------------+---------------------------------------------+----------+--------------------------------------------+

#### 4. Signal Path and Control Components

Code:

+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| Component                    | Specification                               | Quantity | Description/Notes                           |
+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| Volume Potentiometer         | Blue Velvet, 10kΩ, Audio-Taper              | 1        | Controls overall volume before tube stage    |
| RCA Input Jacks              | Shielded, Mono                              | 2        | One per channel; high-quality for audio fidelity|
| Headphone Output Jack        | 3.5mm Stereo, Gold-Plated                   | 1        | High-quality, gold-plated recommended        |
+------------------------------+---------------------------------------------+----------+--------------------------------------------+

#### 5. Grounding and Protection Components

Code:

+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| Component                    | Specification                               | Quantity | Description/Notes                           |
+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| Fuses                        | 1A Slow-Blow, 250mA Slow-Blow, 500mA        | 3        | Protects AC input, B+ supply, and low-voltage DC|
| Star Ground Bus              | Bus bar or Heavy Gauge Wire                 | 1        | Central ground point to minimize ground loops|
| TVS Diodes                   | Suitable for AC Mains Protection            | 2        | Protects against voltage spikes             |
+------------------------------+---------------------------------------------+----------+--------------------------------------------+

#### 6. Chassis and Mounting Components

Code:

+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| Component                    | Specification                               | Quantity | Description/Notes                           |
+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| Chassis                      | WHAMMY Case, 80mm (H) x 210mm (W) x 230mm (D) | 1      | Accommodates all components; ensure proper ventilation|
| Mounting Hardware            | Screws, Standoffs, Thermal Paste for Heatsinks | As Needed | Secure components within the chassis      |
| On/Off Switch                | SPST, Rated for AC Mains                    | 1        | Controls power to the amplifier             |
| Fuse Holders                 | Inline Holders for Respective Fuses         | 3        | Mounts for 1A, 250mA, and 500mA fuses       |
+------------------------------+---------------------------------------------+----------+--------------------------------------------+

#### 7. PCB and Miscellaneous Components

Code:

+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| Component                    | Specification                               | Quantity | Description/Notes                           |
+------------------------------+---------------------------------------------+----------+--------------------------------------------+
| PCB                          | 2-Layer, Custom-Designed                    | 1        | Designed in KiCad; ensure high-voltage isolation|
| Connectors                   | Screw Terminals for Transformer Connections | 1 Set    | Facilitates power connections to PCB        |
| Wires and Cables             | Various Gauges, Shielded for Audio          | As Needed | High-quality for signal paths; proper gauge for power|
| Thermal Vias                 | For Heatsink PCB Areas                      | As Needed | Enhances thermal management on PCB          |
| Mounting Hardware            | Screws, Standoffs, Spacers                   | As Needed | For PCB and component mounting within chassis|
+------------------------------+---------------------------------------------+----------+--------------------------------------------+

---

### Seeking Your Expertise

I would greatly appreciate feedback on the following aspects of the design:

1. Component Selection:
- Are the chosen components optimal for the intended performance and reliability?
- Suggestions for higher-quality alternatives, especially for critical components like capacitors and resistors?

2. Circuit Design:
- Any improvements or modifications to the tube stage or MOSFET buffer for better performance or stability?
- Recommendations for additional filtering or decoupling to enhance audio fidelity?

3. PCB Layout:
- Best practices for minimizing noise and interference in a hybrid tube-MOSFET design?
- Tips for effective thermal management on a 2-layer PCB?

4. Safety Considerations:
- Additional safety features or precautions that should be incorporated?
- Suggestions for ensuring reliable isolation between high-voltage and low-voltage sections?

5. Overall Design:
- Any potential oversights or areas that could benefit from further optimization?
- Advice on achieving the best balance between simplicity and performance?

---

Thank you in advance for your valuable insights and suggestions!

Looking forward to your feedback to refine and enhance this amplifier design.

pelanj · 2024-09-19 9:14 pm

After a break from speaker building, I got an idea to try something that is not very commonly seen. A triangular dual flare MEH. If it will be ever built, I will most probably start with two mids and one bass unit without any back chambers. First rendering tells me this would be definitely an eye catcher:

And a partial side view:

The two mids (3FE22) will be mounted on the left and right sides, the woofer from the top. Not decided on the woofer yet, it will be an 8" or 10" depending on how large I can make the panels.

Prashanth Suvarna · 2024-10-04 3:13 pm

Hi there! This is Prashanth from Mangalore, South India. I'm 65 and I'm a veteran on almost all container el equipment try 4m valves to anything latest as long as it is analog. Hope 2C u on the site later. Thank you, Bye…

Lee in Montreal · 2024-09-13 4:53 am

I am currently building clones of the KEF KUBE 200 equaliser
I want to find replacement OpAmps that are exact replacements for the now obsolete NE5532N or NE5532AN that can be sourced from Mouser or Digikey, not AliExpress

reebop · 2024-10-02 4:47 pm

I've got a McIntosh MA230 integrated amp. This amp has a tube power amp with a solid state pre-amp. I'm experiencing a buzz/hum through the speakers (Heresy 1) that increases as the volume is turned up. This happens when no audio sources are connected and when they are. When I turn off the speakers using the speaker switch on the amp and turn up the volume up all the way, there is a very slight, almost inaudible hum that I feel is consistent with the amp totally cranked. This is a 100 year old home so the wiring is anybody's guess, but I ran about 75 feet of quality extension cord into the basement an plugged the amp into an outlet connected directly into our electrical box which was upgraded maybe 25 years ago to breakers and current code amperage. I imagine this outlet is the "cleanest" in the house. The amp being from around 63/4 has a two prong plug and isn't designed for a 3 prong. Any ideas?

filenet · 2024-05-24 6:41 am

I am in love, again, i canot help mysef.

This time i want to build an amplifier with the following goals:

-chassis footprint 255x305mm, monoblocks
-use 845, not the boring 300b,Tektronics engineer choice
-i am not going to use big, heavy, ugly and ultrasonic(trouble maker) iso or monolith output transformers

The schematic almost drow itself. Even my mother can understand it( by the way, my mother is an NATO consultant in electronics engineering).

NickKUK · 2022-07-24 10:32 am

So with the tube circlotron HPA in progress I'm researching my next project - my first and small guitar amp for small room/practice.

Used to have a solid state Marshall practice amp back in the 90s (IIRC a Lead 12) with a Boss DS-1 and Boss Pitch shift & Delay. I still have my old Japanese fender in good condition but over the years my amp/pedals disappeared (I think during house moves). So with a good dose of Maiden, Megadeth, etc and Police etc I'm quite interested in building a guitar amp. Yet I know nothing of getting amp tone/distortion.

Researching - the JCM800/DSL seems to be a good tonal fit and there's examples of people creating 1W and 2W - although I note that the 2W differs quite a bit (including tube rectifier). I'm also thinking of going down the EF80 output stage but keeping the three stages of the larger JCM as most seem to want some form of tube screamer or distortion pedal head of it. The later DSL seemed to have a nicer tone to my ears bit that's what I'm sort of interested in dialling into. I was thinking of a Vintage 30 (60W) which may be too underpowered by the EF80.

Rob has a great page on this: https://robrobinette.com/RR2104_Master_Volume_Micro.htm#JCM800_Micro_EF80
M. Huss has some good information https://mhuss.com/MyJCM/

I understand that the original Drake OT supposedly gives a better sound than the modern transformers (I see amp garage has a Drake teardown here).

Has anyone here any experience/advise on this?

Hakstone · 2022-04-09 8:31 pm

Hello all. I bought a used ds939 that worked fine till recently. No left channel on A or B. Switched speaker cables to verify it's left only. I'm fairly familiar with electronic parts. I have my own ohm meter and can soldier. Any help on where I should start looking for issues would be appreciated. Thx

Fuling · 2024-09-29 12:45 am

Ok, not much of a "design" yet but please have a good look at the picture and let me know what you think of the ingredients:

leftandfred · 2020-11-29 2:06 pm

Hi,
Could anyone please advise me on trying to repair a dcs Verdi encore transport mechanism?

The disc loading tray seems completely dead and will not open at all

(If physically opened still no reaction from open/close command)

The unit displays “none encore” on start up.

When pressing the eject button I hear a relay click but no action at all.

I have dismantled the transport and checked for obstructions or a loose or snapped belt etc but all seems ok.

It could be that the transport is not receiving the commands from the main pcb, I’m just surmising that it would be the transport unit at fault as I’ve read these could be unreliable

Can anyone guide me on a pin out test for the transport so I can check that it is receiving the command to open?

Does anyone know the exact Philips transport model details? The plastic transport unit has a sticker on saying model A97SL and has a PCB control board with the numbers 3139 243 31374 01

Would this same transport mechanism with pcb be used in other machines? Maybe I could purchase a second hand sacd/dvd unit that uses it.

Any help and advice much appreciated.

Best regards
Dave

Surtsey · 2024-10-03 3:41 pm

Using dumpster parts I made a remarkably system for our outdoor barbecues. I'm moving but my 2.1 amp is coming with me. Just as an exercise I want to rewire the speakers to be driven from a stereo amp.
If I convert the sub to passive stereo it will be 6 ohms. The satellites are also 6 ohms. This gives me an impedance of 3 ohms per channel. If I use a cap as a high-pass filter to limit the mains to 100hz+ will I get to 4 ohms nominal.

Booger weldz · 2024-10-02 10:03 pm

https://techtalk.parts-express.com/...minisculities-and-goosebump-pr-bandpass/page3

@wolf_teeth
Can we try this with the tangband w5-1138f and the $40 7” dayton epique passive radiator?

https://www.parts-express.com/Epiqu...iber-Cone-Passive-Radiator-295-114?quantity=1

lexxtox · 2022-09-24 11:42 am

Hi All,
Have a few Sanken S-40W, S-60W, SP-40W Modules to clear. They are Not Brand New but NOS , never been use.
Please Note some of the modules case were scratch , they live their life in an unprotected plastic bag.

grlazy · 2023-03-31 7:08 pm

I have had a pair of Kef c7 first hand for several years. I really enjoyed their sound.

In January one tweeter stopped working.
So I unscrewed the face plates and did a tweeter switch (from one speaker to the other) to check if this is it (and unfortunately it is tweeters fault) and it is not a crossover issue.
I have been in contact with the representative in Greece but for 2 months now they can't find it.
They tell me that because of covid everything is late and wait some time more etc.
So i am alerted that i won't find anything and i am in search for a speare one. I've also looked on ebay but I can't find it there either.

I'm desperate, I liked their sound and I didn't want to change them. But I don't see any other solution.

I emailed gp electronics & acoustics co. ltd which is probably the OEM manufacturer. No answer.
The same for KEF on FB.

Searching the internet I found the following (which comes from the attached pdf)

The speakers are the ones at the attached picture. They have a front wooden/black painter plate to cover the speakers bolts.Tweeter is shown at the other picture.

Any ideas with what tweeters i can replace the old ones? Maybe a modification ?

ICG · 2024-10-05 1:49 am

Hi everyone!

Let's assume, you've drank a lot, are agitated or not able to sleep, maybe too much caffeeine, it's late at night, what do you do? Pestering the forums with stupid questions, arguing about things of the past, ponder about what driver to use? Please tell me to distract me from my sleepless night..

baller · 2024-10-05 1:48 am

I have a KEF C series system that I am trying to maintain and keep alive. Unfortunately my tweeter failed on my CLR6 centre speaker. And now I'm trying to figure out how to repair it.

gperpetuo · 2024-10-05 12:38 am

Hi everyone,

I'm kind of new to Audio DIY although I've been making all kinds of DIY hobbies through the years, from aeromodeling, some woodworking, 3D Printing (own a Voron), etc...

Made a Protodac as first DIY audio gear recently and been enjoying it quite a bit with the rest of the audio gear (only had a turntable and the TV connected to the amp... and a DAC/Streamer came quite handy for when I don't wan't be be playing with disks so much)

Hope to learn much more here!

Regards,
Gonçalo

Wil_NL · 2024-10-05 12:19 am

I am an audiophile and often looking for affordable improvements to my audio system. I like analog and natural sounding systems. During an audio fair I heard the Pearl Acoustics Sibelius speakers and I was immediately sold. Unfortunately the speakers are too expensive for me. Thanks to a thread on DIY I got the idea to build the speakers myself. These will be the 2nd speakers I build myself and probably also my last!!!

The Real Andyman · 2024-10-04 7:17 pm

Andy from from the cold, dark north of England. Not much into DIY to be honest. But “enjoying” a couple of the threads on here…

Jason · 2021-12-09 10:44 pm

Update: Please make sure you have read Jason's post #513 before replying into this thread instead of using the new forum we have created to collate new issues called "New Platform Issues".

After a 36 hour marathon migration, we have our new home!

It was important for us to get off our old software as soon as possible, rather than wait for the new software to be perfect. Your bug reports and constructive feedback are welcome. They will help guide us make the right decisions to improve the site in the future, and to clean up any issues.

Planning, development and migration was performed in partnership with Xenforo experts Audentio. You might see some of them chime in to this discussion thread.

PS make sure you check out the theme chooser which gives you three theme options - light, dark, and classic.

Angel Fonseca · 2024-10-04 11:28 pm

Hello, I have a problem with an alpine MRD M300 amplifier. Does anyone of you have information about it, specifically the oscillation stage?

richgwilliams · 2021-05-23 10:28 pm

I had two Fluke 8010A Bench Meters both with broken LED displays (they go black). First time I looked at replacing the LCD with LED it looked impossible because the common BP (backplane) signal reverses phase constantly relative to the segment drive signals (that's what LCD displays need to work).

A few months later I had another look and realised that a pnp transistor could use the BP signal to strobe the right phase for four Common Cathode Seven Segment LED's by doing this:-

"Connect BP signal to base of PNP transistor via 3K9 resistor, Connect its emitter to all four LED common cathodes, connect its collector to - Vss
(Note BP drives U6 for the decimal points)"

Solder wires from the previously LCD connector to your four common cathode seven segment LED's. See attached pinouts etc. Only three of the LED decimal points need to be connected to U6.

The ICL7106 doesn't have much drive but its enough to get a tidy LED display, don't include any series resistors. The LED's take a bit more current so its a good idea to increase the power supply smoothing capacitors (double the uF value)

So end result is an excellent and accurate Fluke 8010A with four digit LED display (the MSD LED only displays "1" and the negative sign.

The Fluke 8010A has a very small supply transformer and only consumes a few watts. I have one of the 8010A's permanently on monitoring a battery voltage.

ngen33r · 2019-11-24 10:54 am

Hello All

I have been repairing Klipsch subwoofer amps for about 15 years as a hobby. I have decided to start blogging my repairs and eventually do videos of each one. This thread is intended to be a blog and a resource for information. I will try to answer repair questions as best I can. Comments and tips are also welcome, If you do not have the experience or the tools, PLEASE do not attempt any of these repairs. You will only end up damaging the board and it will end up costing more for a tech to repair the damage. If you do not have a high quality vacuum desoldering station (Hakko or Weller) and a current limited mains supply, you should not be working on these amps. These subwoofers do not have any user serviceable parts inside. If you open up the sub or attempt any repair you see in this thread, you are doing so at your own risk!!!

The PDC board 660038RA (main supply control) is almost always the main failure mode of these amps. The glue that was used becomes conductive and kills the board and the fets (planned obsolescence?). These boards are typically made in China and are super easy to damage. If you don't have a desoldering tool you MUST cut the board off and remove the legs from the thru holes one by one. Once the thru holes are damaged the repair becomes a difficult hack job unless you have a thru hole repair kit.

The other most frequent failures are the Bash control board and Q5. If Q5 is SOT-23, it needs to be replaced with a TO-92 2N4401. This mod was done on later revisions most likely due to warranty claims.

I have made a schematic of the PDC board and I also have made replacement boards (I do not sell or supply these boards). Sometimes they are so badly burnt, they have to just be replaced.

qbas · 2024-10-04 8:46 pm

Hi,

My name is Jakub. I am interested in building a single driver speakers myself and that is why I am here 🙂

Regards

Andrew Eckhardt · 2024-10-04 9:27 pm

Anyone have a circuit drawing? I'd like to implement a soft power switch..

ginetto61 · 2024-08-10 7:15 am

Hi to Everyone !
I seem to see a continuous and enthusiastic search to achieve the lowest possible levels of harmonic distortion in circuits
Every now and then I read that below a certain level (that I have not understood well) any improvement in terms of lowering harmonic distortion practically becomes inaudible in normal listening conditions and can be appreciated only with the best testing lab gear
Question Is there any agreement on what this level is?
Thank you very much and best regards
gino

P.S. I well understand that The lounge should be a place to discuss topics that are not audio related,
But i have sometimes doubts so generic that do not fit in any specific discussion and other members could easily get annoyed by maybe trivial topics
Thank you very much

Geoff H · 2006-12-01 9:40 am

Hello everyone.
Over the past week, there appears to be more than just a bit of interest in Altec Lansing. You know, the real ones.

We have had a member selling some. (there was more in that thread after they were sold than before) A member building a system I thought may have been modelled on an Altec, enquiries about cabinets, same raving, and why not! Even a mod got entangled in a hijack. No names.

So how about a thread for Altec Lansing? It can cover anything you want in the way of their speaker range. Cabinets, mods, pictures, data sheets. Even experiences. It could include the MM stuff (they are good for what they are) It doesn't have to compete with Lansing Heratage, however it could compliment it.

For those not fortunate enough to have heard these speakers, most of us that have, even in the long distant past, do not forget the sound. And many will try to emulate it.

So how about it? Show us your Altecs, share the pleasure and the dramas. Lets show the current manufactures some real magnets, cones and horns.

Geoff

BrianGasberg · 2024-09-27 5:31 pm

Hi Guys,

I am seeking some advice regarding what could be the issue with my turntable. I am experiencing a somewhat distorted sound while playing LPs - it seems that it mainly affects the instruments and to a lesser extent the vocals.

I have made a quick video recording here: Login to view embedded media
It is supposed to sound like this: Login to view embedded media
Do you think it is the Pickup which is done? or might it be an adjustment thing? needle pressure e.g.

i bought the turntable used, close to a year ago, anticipating the Pearl 3 RIAA, and it has been playing great since, however it is my first turntable so i am not that experienced regarding things that might be going on in a turntable. It is a Rega P3-24 with a Rega Exact pickup.

I have tried a different RIAA - it did not change anything, and there is no issue when i stream something, so it is isolated to the turntable.

RayD8r · 2024-10-04 7:03 pm

I am researching the next level of audio performance as I have pretty much topped out, at least from my perspective, in the box store and online sector of home audio. I have an Onkyo TX-NR6100 and a mix of Klipsch reference and reference premier speakers for a 7.2 HT with Atmos main system. I also have an Onkyo TX-8220 with some JBL Venue series speakers that I have on zone B from the 6100 in my room. I have this setup so I can listen to my tunes throughout my place without having to turn a single system up loud enough to get complaints from other tenants. Lots of speakers at low volume works. I started out with a TX-SR393 and a "HT in a box" speaker package but I spend about as much time in my room as I do in other areas of the apartment and if I turned it up loud enough to hear in my room, the neighbors would complain.

I know I could get a little better out of general store bought equipment but it seems like pretty much a lateral move with only a little better performance so I'm researching moving into a higher level of audio system. It's a balancing act for me because I don't have a lot of funds to throw at it. It's taken me well over 5 years to work up to what I have by waiting for big sale events and wheeling and dealing in the used market but I've done pretty well. To buy everything I have at full retail would be significantly more than I actually have into it. I'm actually quite a bit below half of what full retail would cost and it's all in either new or like new condition with the exception of the JBL venues which I have "made my own" by replacing the grill cloth and painting the accent panels and trim rings and replacing the "JBL" decals with actual aluminum badges. I also had to replace the amplifier in the Sub 12 and sounds like I'll also have to replace the one in the Sub 10 eventually.

The system as a whole sounds really good and suits my needs and looking into this "next level" I'm finding that in order to get a what I consider marginal amounts of performance, a lot of money is spent in the form of devices used to refine or "clean up" the audio signal from the source. It's also been my understanding that adding devices to a system also adds noise. I'm assuming then, that it all depends pretty much on the quality of the devices which in turn depends on how much it costs. So is it a toss up on initially spending more on source equipment that outputs better signals than adding devices necessary to refine the signals from lower priced equipment, or does one still have to add expensive signal refining devices to already expensive source equipment?

If that's the case, I believe I will just settle on the pretty decent stuff that I have and find another hobby. Any thoughts on this subject are much appreciated and thanks in advance.

sal_cats · 2023-08-06 3:08 pm

Due to health issues, I can't complete this project so it's here for sale.

I originally bought this bundle from someone on this forum, the original thread has some details and pictures

https://www.diyaudio.com/community/...id-transformer-heatsinks.384794/#post-7042520

I'm looking for £350.

Based in Bristol, UK.

Currently looking for UK sale, ideally collection but can post.

andyjevans · 2023-06-16 10:43 am

The Kef B200 was in loads of speakers around the 1980s, and there still seems to be a few about.

Rubber surround so no foam to rot.

So the question is "how good is it"? Is it worth using for a 2-way speaker project, either sealed or ported?

Is it still competitive or are there better 8" drivers available these days?

The SP1014 is the common one with the smaller magnet. Are the larger magnets any better, like SP1039?

And I gather the crossover needs to be 3K or below, but I haven't seen any frequency responses for the B200.

So - worth using or pass?

MalVeauX · 2024-10-03 7:56 pm

Hi all,

I'm thinking of playing around with an open baffle monitor using these drivers:

1 x GRS PT6816-8
2 x GRS 10PT-8 (parallel, did two of them for the excursion and sensitivity to bring it up)

Just fooling around in X-sim to see if they're even remotely compatible in a meaningful way without requiring super complex passive crossover. But, I'm very weak with crossover design and mostly use full range drivers. So any help is appreciated if anyone has a moment!

I tossed in the drivers in X-sim and did a simple set of low pass and high pass to get a general idea of things and how the impedance would be.

I don't need it to be super flat. I mostly just want to get to about 70~80hz on the low end before I crossover to a sub. I imagine I will do this on the thinnest baffle I can and will add some wings assymetrically to the sides, then measure, then re-do the crossover. So this is more of a preliminary attempt to see if they will even work together passably. I have the PT6816 drivers, but I do not have woofers yet, so I'm open to something superior for the role in a similar price range (~$30 per driver).

I've attached my X-sim model here to this post so it can be loaded with the drivers.

Thanks!

Very best,

RickV · 2024-10-04 3:21 pm

Hi, I'm a retired engineer who dabbles in all types of repairs - auto, appliances, and occasionally electronics. I live in Canada, near the US Border of Detroit. I own a Klipsch sub-10 Subwoofer that won't power up, and I'm looking for help to get it functioning again.

Bmsluite · 2024-09-23 4:51 pm

This is my first series crossover so I would like someone to sanity check my work.

Background info and disclaimer:

1. Yes, I do know these are bass heavy. This whole build is made around some leftover Silver Flute woofers I had laying around. It is what it is.
2. In order to match the sensitivity of the woofer I needed a low impendence tweeter which forced me to series crossover. I can do it parallel and get to 3 ohm but that will still require a dedicated amp for this build which I am trying to avoid.
3. This by no means needs to be a perfect build. As long as it sounds ok I'm fine with it. It will be much better than the crappy sound bar that is currently at the family lake house.
4. The tweeter is utter crap below 2khz.
5. The woofer has a stupid breakup node at 5100 hz and I just cannot seem to get rid of it with a series crossover
6. This is all measured data.

gerrittube · 2024-10-02 12:11 pm

My KT150 PP project showed a lot of distortion yesterday. I discovered today that 2 cathode resistors (2.2 Ohm each) had gone south. One measured 33 Ohm, another 160 Ohm.
In the cathode lead I have a string of 3 resistors: 2.2 Ohm, 2.2 Ohm and 1 Ohm, 5.4 Ohm in total. With an automated bias module the cathode voltage is compared with a voltage reference. This works fine and I had set the cathode current to 90 mA.

Of course I ordered new resistors today (TO-220 again, now 50 Watt max.). I know the cooling is not exceptional, but with 2.2 Ohm and 90 mA (0.01782 Watt)?

I just cannot understand what may have caused damage to these resistors.

Regards, Gerrit

mdye · 2019-05-12 4:30 pm

Hello,

I just purchased the TU-8200DX kit, and although it hasn't even arrived yet, I've started going through my tube stash pulling out all of the 6L6GC tubes I have as well as their relatives. I haven't been able to locate a list of all of the compatible tubes for this amp, other than what is advertised by Elekit (6L6GC, KT66, KT88, EL34, etc.). Sounds like the voltages in the 8200 are too high for the original 6L6 metal base 6L6G varieties, however can someone confirm whether or not the following can be safely used (regardless of pentode, triode or UL modes)?

5881/6L6WGB
807 (with adapter)
6BG6 (with adapter)
7581

Any others that I'm not thinking about? Has anyone measured the plate and screen voltages applied to the power tubes in the TU-8200?

Thanks for your help!

reins · 2024-10-04 3:06 pm

Hi,

ideally I would like to sell my leftovers from DIY speaker building for small money in total.
I'm located near Munich in Germany, so you could also pick up the items. I have all the parts for some years, the condition is normally VG+.
Parts:

2 circular horns 6" for compression driver
2 circular horns 10" for compression driver
2 Stage Line MRH-80 high range horns
2 WG-300 waveguides
2 Stage Line MRD-90N horn drivers
2 Vifa HT 200 F/6 tweeters
2 Scan Speak D2604/8330000 4Ohm tweeters with attached WG-300 wave guide (wooden adapter). Original front plate is available
1 SB 29RDC-C000-4 tweeter. Condition unknown. Don't know why there is a single tweeter :-(

For any questions, feel free to contact me.

BR

Jizzy · 2024-09-03 4:06 pm

Hi, I am interested in building a Hog Scoop enclosure for the 18sound 21LW1400 speaker, similar to the design described here: https://www.freespeakerplans.com/?view=article&id=31:hog-scoop . Currently, I have two of these speakers mounted in bass reflex boxes, but I’ve noticed that the sound doesn’t seem as powerful when used outdoors.

I would like to know if the Hog Scoop design could provide more SPL compared to the bass reflex enclosures I am currently using. I am particularly interested in improving low-frequency performance and achieving a louder and clearer sound in open spaces.

Thank you in advance for your response and any suggestions you can offer regarding my project.

platan · 2024-10-04 1:22 pm

JBL M2 tweeter (D2430K) pair, in sealed boxes. Only Europe area. Price 1400 Euros, plus shipping.

willcycle · 2024-09-30 11:59 am

My Mark Levinson 380S preamp forgets its input names and gain settings after it is powered down and back up. If I reprogram them they are restored, however, after powering down and back up at a later time they are forgotten. There may be a default labeling of inputs when not programed, for instance input 1 always comes back as CD 1. Is there a charged capacitor that maintains the settings of a memory chip or perhaps something wrong with the memory chip and does anyone know which one it would be? The preamp works normally otherwise.

svp · 2024-09-12 12:10 pm

Hi there,

Couple months ago I decided to step up my audio measurements "game". Bought dbx RTA-M uncalibrated microphone (no downloadable file, no mentioning that it is somehow calibrated, just the overall quality claims from manufacturer). It was praised by local salesman, who had just this one and couple of other models in stock with similar pricing. None of them with calibration file. As it was my first reasonably good measurement microphone, I assumed, that it is more or less flat and is more than sufficient for homemade speaker projects. But the doubts were there and...

I bought cheaper, but calibrated Dayton EMM6 couple days ago and... Now I got real headache. Below are the measurements of dbx and dayton. No matter what levels, no matter what REW options - the curves are exactly like this:

I admit, that the speaker Dayton PS95-8 I am measuring has some rising response, but it is around the levels of dbx, which is similar to manufacturer curve, I do not fully trust dbx, but Dayton is DOA, landfill or similar quality. Calibration file of Dayton is in ~3dB range, there is no curve similar to ~20dB difference. Or maybe I am doing something very very wrong?

My ears are good and I understand that I am not measuring flat speaker with flat microphone, but the real perception of sound is in the dbx curve.

p.s. I will try to get some local help to compare my mics to the some more expensive one, stay tuned.
p.p.s. dbx was used ~10 times/days, dayton ~2. There are no damage signs on any of them, they are new and look as new. Handled with care when in my posession.

kmj · 2024-10-01 1:40 pm

Looking for an Icepower module with integrated powersupply in the European union.
Around 2x200W or higher.

Anyone willing to sell me one and ship it to Sweden?

planet10 · 2024-10-03 11:58 pm

Not sure if this is the best forum to put this…

https://audioxpress.com/news/tascam...e-audio-field-recorder-and-timecode-generator

dave

rthorntn · 2024-09-29 8:42 am

Hi,

Anyone have any recommendations for a 4" driver that will be happy sealed and can cover 100-5000Hz well in 2.5-way DSP crossover, available in Australia for no more than $175AUD per driver?

@mayhem13 recommended the ScanSpeak 10f-4 but I can only seem to find the 8ohm here.

Thanks!

muchosmitsos · 2024-10-04 10:48 am

Hello

i am Dimitri from Greece.

Thank you for your acceptance.

i think i need to reintroduce myself due to a long time being inactive in this site.

I am a huge vintage speaker fan.

vakulenko · 2024-10-04 10:09 am

Hello, fiiends!
I need to power pre-amp based on NJM4580 chip. According to the datasheet, the chip is powered by a voltage of ±2 to ±18 volts. The input signal will be ±1V, the output no more than 3V. Most of the circuits I have seen use a voltage of ±12-15V. Will a supply voltage of ±6V be enough for me? Or will this negatively affect the quality of the output signal? I want to use the lowest possible voltage to reduce the size of the capacitors and transformer secondary winding.
Thanks for comments!

ginetto61 · 2024-10-04 8:18 am

I just received the title unit in its Version 3
It is really changing my way of thinking and opening my eyes
First of all being unable to make a hard boiled egg after some setting problems in Windows it seems to me that it is user friendly like few units
It also seems very accurate and the measurements very repeatable
And it is making me understand things
An example
Some time ago I bought thinking I had done a smart thing some ITT made vintage midrange domes marked on the magnet
LPKM/105/37/120 FTR
one has fs=1kHz the other fs=1.5kHz
And also the impedance at fs is quite different 😕
in a word unusable Money completely wasted
Probably the business for someone is to cannibalize old speakers of their drivers and resell them to some idiot like me
Now I am aiming for new drivers from manufacturers with a good reputation
I am Italian and fortunately in Italy we do not only have the mafia but also Faital for example
Never used again and never again vintage
Without having measured the impedance first of course 😉
It is really the case to say one small step for man, one giant leap for ginetto61
Have a good day everyone
gino

P.S. next in line mains power transformers I am sure that their impedance sweep will tell me things

EvanF · 2024-10-02 4:25 am

I am doing a full recap of these speakers and am wondering if these will improve on the Jantzen standard Z-cap and ClarityCap PX I already have in there. Anyone familiar with this brand? I also have 47uF 100V non polar Dayton brand electrolytics in there and am wondering if replacing with 47uF film would be wise.

Buddy01 · 2024-10-04 8:21 am

Greetings,
I'm a retired audio and automation engineer living in Tasmania, Australia. I've just finished building a house in a place called Seven Mile Beach and I now plan to fill it with audio equipment that I've always wanted. However, whilst they sounded good to me, visually were pretty ordinary. So I'm focussed on scratch-building replica audio equipment with my own design appearance. The nostalgia of the simpler (and analogue) times, as us oldies do. (mostly)
So currently in mid construction are: 2 x VTA valve mono amps; 1 x VTA valve preamp; 2 x Dynaco 416 power amps; Marantz 2275 receiver; Luxman 3-way active x-over; AR 3a speakers; AR LST speakers; AR XB turntable.
Good to be here.
Regards.

hanzooo · 2024-10-01 8:04 am

Hello,
I am looking for the electronic diagram of this amp or the component references (all mosfets, dual diode, C5, D32, D48 and R104.
THANKS

currop · 2019-10-02 11:58 am

Hi everyone,
My name is Francisco, and I am new in this forum, hope I can learn and help in my short possibilities! (I am new in the vintage and Hifi world)
I have purchased a 1976 Technics SU7700 which seems to be in good conditions, esthetic is perfect, but once I begin to play music there are some issues I want to know if can be solved with a recap of the 36 electrolytic capacitors, (I found a Nichicon kit for this amp). The ratings of this amp in internet make me think that it should sound quite better! My problem is to know if it is a good investment to recap or it needs other major electronic reparations that could rise the money I will need to put on it.
Before testing I have cleaned all the PCB, I have changed a 500 mA fuse that protect the vumeters lamp and I have tried to lubricate/clean the volume, balance, bass and treble knobs, but I think the job done isn´t enough. Should I dissamble all the cable connections from each potentiometer and extract them from the main aluminiun front cover for clean them properly?
1) The first test have been done using a mobile phone as source, connected to AUX, TUNER, PHONO and TAPE (playback). The loudspeakers have been connected biwired to main and remote connections. The problem, apart from the poor performance, is that the R channel sound very weak, and if you turn the balance to force this channel it doesn´t get better. This happens using all the sources, unless I connect the mobile to PHONO, where it sounds higher but without good quality. In TAPE the sound has a little more power and in TUNER and AUX there isnt´t any sound in R channel. I have not tested with other source, no CD player nor tuner.
2) If I check the headphones connection now it sounds in stereo, but again, the sound quality is bad, and if the volume knob is turned, it scratches a lot. So I know it needs a good potentiometers cleaning.
3)Other problem is the noise that produces the system all the time, which can be well checked with the headphones. Maybe I need to connect the ground of the amp to the ground of the house, as the 230 V cable of the amp doesn´t have ground line? The noise depends of the position of the minijack connected to the mobile phone.
4)I have noted that in the Technics manual there is an explanation for alignment, that can be done testing with a voltimeter each channel. If the measurement is over 25 mV it needs a bridge connection to be cutted, the same process for each channel. In my amp, this bridge connection has been cutted only in one of the channels, so I think that someone did this checking before. This can be the cause of the poor performance?
5) Finally, I have noticed that the thermal paste used for the connection of the power transistors to the cooling fins is not dried, once you touch you can remove it.
Best regards and thanks !!!

presscot · 2024-10-04 5:24 am

I’m going to add bass extension to my 2-way speakers. The speakers consist of 1” SEAS H400 tweeters and 6.5” SEAS H602 woofers. I still have a pair of the H602 woofers unused. I think of 2 methods for the upgrade.

A) passive subwoofer
Build crossovers and enclosures for the remaining H602 and use them with the existing 2-way speakers but leave the 2-way speakers untouched—no high pass for the 2-way.

B) convert the 2-way to 2.5-way system
Add the unused H602 to the 2-way and redesign crossovers to the way 2.5-way did as shown in the picture.

_community_attachments_2-5-way-crossover_version-2-jpg.536446_.jpeg

Which choice is more suitable?

Raghukanth Joshi · 2024-10-03 10:35 am

Hi All,

iam having an power amplifier Perreaux MC6100 all of its caps have gone bad which are of capacitance 6800uf 80v, my question is can i upgrade all the caps with 10000uf 80v elna audio grade capacitor of same size as iam unable to procure 6800uf 80v caps good Audio grade ones?

https://www.highperformancestereo.com/perreaux-6100-6-channel-amplifier.html

any pointers are much appreciated.

Thanks
Raghu

capslock · 2024-10-01 9:50 pm

This is about the 8930B calibrator for 1/2 inch microphones. I got mine from Thoman but I see it is now also available from Aliexpress.

https://images.static-thomann.de/pi...U5NjNka1UydndISEZVYWxFNlBiSUE1SEtFZUElM0QlM0Q.

The manual says this:
Carefully insert microphone up to the stop within the calibrator cavity. The O-ring will offer some resistance.

I suppose they want to tell the user to stick the microphone in all the way to the stop. And it makes sense in that the initially cylindrical entrance hole ends in a ridge that is about 1 mm smaller in diameter. Behind that is a hollow half dome chamber. The insertion depth is about 12 mm.

I was sceptical about this because on all B&K and Norsonic capsules I have, the protection grid is somewhat wider than the capsule itself. So the O-ring seals tightly during the first 7 or so mm and feels kind of loose the moment it sits on the capsule rather than the grid. Of course, the reading gets higher when the microphone is fully inserted.

However, I just bought my first new in box sound level meter, and it displays 93.8 dB out of the box only when fully inserted.

rthorntn · 2024-10-04 2:22 am

Hi,

So I saw this image and it made me realise that I might not understand balanced, I just thought it separated the grounds so you could double the voltage and that was better for longer cables, resistance to interference and making (headphone) amps play louder (I think a power amp sort of "multiplies" sound, so say 2V x 10W is 20W then 4V x 10W is 40W I think this is probably way oversimplified).

Then it occurred to me (I was told that the analogue section of most DACs is what let them down) that a balanced DAC might have twice the (what I'll call) "bandwidth" like 4V means more "signal". I read 3dB more dynamic range. Do you get more "resolution"?

I also read some ladder DACs improve balanced, like maybe you can have more steps in your ladder?

The CamillaDSP setup in the image is using two channels on a DAC changed into one channel balanced, is that going to "measure" better?

I was also chatting about (digital) volume and that you lose headroom, do you get more headroom with balanced, I have got to admit that I don't fully understand (a lot of advanced audio stuff including) headroom.

Can someone please sum things up for me?

Thanks.

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