MiniDSP 2x4 HD with UMIK-1
Barely used MiniDSP 2x4 HD and UMIK-1 signal processor/electronic crossover and measurement microphone. Purchased in 2021 for a speaker project it took much too long to finish.... used for a couple of months in 2024. Works flawlessly, except for the original wall wart that had to be replaced (replacement included; original discarded with extreme bias). All original boxes and parts included. $200 shipped to the USA. You will need a license for the software, which I can transfer to you after purchase (MiniDSP allows transfer).
Attachments
Transnova anyone?
- By mlloyd1
- Solid State
- 16 Replies
A few days ago, I posted some questions about the Transnova amplifier design in the “acoustat-answer-man-is-here” discussion group in case he could share any insights from his time at Acoustat, where the design originated. I know he focuses on speakers and didn’t have much he could share. So, I mentioned I would bring up the topic on the solid-state group.
Over the years, I’ve read through a number of Jim Strickland's notes & schematics on the early Acoustat TNT Transnova amps (TNT-200, TNT-120) while comparing to the later Hafler Transnova versions (9500/9300, 9505/9303 – Hafler made other Transnova models; I just care about the Hafler Transnova designs that use Lateral MOSFETs). Some of Jim's earlier Transnova papers describe something called "complementary" feedback, which looks to be essentially positive feedback being applied to perform some error correction/cancellation. It looks like that aspect of the unique feedback arrangement was phased out of the Hafler designs. It is R26 in the TNT schematic snippet (blue) attached and Rc in the (attached) patent writeup. I don’t see a similarly located resistor is not present in the Hafler version (yellow attached schematic snippet).
Although both driver circuits are able to pump quite a bit of current into the MOSFETs (at least 40mA), I have read that Hafler front-end improved on the linearity vs. the Acoustat front-end. So, I’m curious if the complementary feedback was dropped because it was viewed as unnecessary with the “new & improved” driver circuit or were there other reasons?
I've heard the Hafler version model 9500 played through some nice electrostatics and my old Kef 104.2 speakers and liked what I heard but have never heard the Acoustat TNT models...
I know a few others around here have commented that they didn’t care for the sound of the Transnova design (anatech, djk, etc.); I couldn’t tell if they referred to the earlier Acoustat version or later Hafler version (or both).
While roaming around through the discussions, from time to time, I see some people around here post about experimental designs they have built that are somewhat similar (low voltage front-end driving grounded source Lateral MOSFET output stage that has voltage gain and floating, higher voltage rails), for example, Juma’s nice “Transnova-Schade OS/Amp. I’ve also seen the AES paper and Linear Audio article written by John Vanderkoy (and others) that uses a high performance op amp as the front-end driver for the same output stage instead (image from abstract attched). One of the key differences is Acoustat’s Tranova approach configure the discrete design front-end as a transconductor with local negative feedback around the output stage (Juma does also), while Vanderkooy’s approach uses the op amp as just a voltage gain block and the output stage has no local negative feedback.
Anybody else out there playing with this design? Any of you even happily cloned either the Acoustat or Hafler Transnova amps?
I attached some reading material that was available freely. Some of this seems harder to find now.
mlloyd1
Over the years, I’ve read through a number of Jim Strickland's notes & schematics on the early Acoustat TNT Transnova amps (TNT-200, TNT-120) while comparing to the later Hafler Transnova versions (9500/9300, 9505/9303 – Hafler made other Transnova models; I just care about the Hafler Transnova designs that use Lateral MOSFETs). Some of Jim's earlier Transnova papers describe something called "complementary" feedback, which looks to be essentially positive feedback being applied to perform some error correction/cancellation. It looks like that aspect of the unique feedback arrangement was phased out of the Hafler designs. It is R26 in the TNT schematic snippet (blue) attached and Rc in the (attached) patent writeup. I don’t see a similarly located resistor is not present in the Hafler version (yellow attached schematic snippet).
Although both driver circuits are able to pump quite a bit of current into the MOSFETs (at least 40mA), I have read that Hafler front-end improved on the linearity vs. the Acoustat front-end. So, I’m curious if the complementary feedback was dropped because it was viewed as unnecessary with the “new & improved” driver circuit or were there other reasons?
I've heard the Hafler version model 9500 played through some nice electrostatics and my old Kef 104.2 speakers and liked what I heard but have never heard the Acoustat TNT models...
I know a few others around here have commented that they didn’t care for the sound of the Transnova design (anatech, djk, etc.); I couldn’t tell if they referred to the earlier Acoustat version or later Hafler version (or both).
While roaming around through the discussions, from time to time, I see some people around here post about experimental designs they have built that are somewhat similar (low voltage front-end driving grounded source Lateral MOSFET output stage that has voltage gain and floating, higher voltage rails), for example, Juma’s nice “Transnova-Schade OS/Amp. I’ve also seen the AES paper and Linear Audio article written by John Vanderkoy (and others) that uses a high performance op amp as the front-end driver for the same output stage instead (image from abstract attched). One of the key differences is Acoustat’s Tranova approach configure the discrete design front-end as a transconductor with local negative feedback around the output stage (Juma does also), while Vanderkooy’s approach uses the op amp as just a voltage gain block and the output stage has no local negative feedback.
Anybody else out there playing with this design? Any of you even happily cloned either the Acoustat or Hafler Transnova amps?
I attached some reading material that was available freely. Some of this seems harder to find now.
mlloyd1
Attachments
-
US4467288 Distortion-Free Complemented Error Feedback Amplifier and Method.pdf
-
Hafler Trans Nova Amplifier 9300, 9500 Large.jpg -
acoustat_trans-nova_twin-200_en.pdf
-
John Vanderkooy v9 jv abstract image.webp -
history-of-the-transnova.pdf
-
the-hafler-tradition.pdf
-
the-transnova-topology.pdf
-
transnova-g,h.pdf
-
Locked
Food for thought
Abstract
This document presents a budget-friendly 3-way bookshelf speaker pair designed to rival popular models like the Polk ES15 and ELAC B6.2, which retail for $250–$300 per pair. The design achieves a frequency response of 34 Hz to 20 kHz (±3 dB), sensitivity of 86.5–87 dB, and power handling of 200 W, using off-the-shelf components and a slanted baffle for improved time alignment. The total cost is approximately $371.64 per pair. This publication details the design process, VituixCAD simulations, performance metrics, and a comparison to five well-regarded speakers in the $200–$1000 range, including horizontal and vertical dispersion analysis.Introduction
Bookshelf speakers are compact audio systems designed to deliver high-quality sound in small to medium-sized rooms. This project aims to create a pair of 3-way bookshelf speakers that offer superior performance to commercial models like the Polk ES15 and ELAC B6.2 at a similar price point. Unlike typical 2-way speakers, which use one driver for bass and midrange and another for treble, this 3-way design dedicates separate drivers to bass, midrange, and treble, enhancing clarity and detail. Key features include a slanted baffle for time alignment, a 4 Ω woofer to compensate for bass loss, and a carefully tuned crossover. The design was optimized using VituixCAD simulations and is ideal for DIY enthusiasts seeking professional-grade sound on a budget.Design Overview
1. Driver Selection and Specifications
- Woofer: Dayton Audio DCS205-4 (8", 4 Ω)
- Handles bass up to 450 Hz with 100 W RMS power handling and ~91 dB sensitivity (boosted by 4 Ω impedance).
- Chosen for its ability to compensate for baffle step loss, where bass weakens as sound diffracts around the enclosure.
- Midrange: Dayton Audio RS100-8 (4", 8 Ω)
- Covers 450 Hz to 3 kHz with 60 W RMS power handling and 86.5 dB sensitivity.
- Selected for its clarity in critical midrange frequencies.
- Tweeter: Dayton Audio DC25T-8 (1" Titanium, 8 Ω)
- Handles frequencies from 3 kHz to 20 kHz with 80 W RMS power handling and sensitivity padded to ~87.5 dB.
- Chosen for its smooth high-frequency response and affordability.
2. Enclosure Design
- Dimensions: 10" W × 16" D (base) × 22" H, slanting to 14" D at the top (10° angle).
- Woofer Chamber: 1.0 ft³, ported, tuned to 34 Hz with a 2" × 4" flared port for extended bass.
- Midrange Chamber: 0.06 ft³, sealed to isolate midrange frequencies.
- The slanted baffle ensures sound from all drivers reaches the listener simultaneously, improving phase coherence.
3. Crossover Design
- Type: Dayton Audio XO3W-450/3K (8 Ω) with crossover points at 450 Hz and 3 kHz.
- Adjustment: A 4 Ω resistor pads the tweeter’s sensitivity to match the system average.
- The crossover ensures smooth transitions between drivers with minimal power loss.
4. Bill of Materials (BOM)
- Total cost: $371.64 per pair, including drivers, crossover components, MDF, and miscellaneous parts.
Simulation and Performance Analysis
1. VituixCAD Simulation Setup
- Software: VituixCAD modeled the drivers, enclosure, and crossover.
- Driver Positions: Woofer at the bottom, midrange at mid-baffle, tweeter at the top (slanted).
- The simulation confirmed frequency response, impedance, and directivity.
2. Frequency Response
- Range: 34 Hz–20 kHz (±3 dB), with an average sensitivity of 86.5–87 dB.
- Bass: -3 dB at 34 Hz, flat from 100 Hz to 10 kHz.
- Highs: Smooth roll-off above 10 kHz, reaching 70 dB at 20 kHz.
3. Directivity
- Horizontal Dispersion: Wide below 500 Hz, narrowing to ~60° at 20 kHz.
- Vertical Dispersion: Narrower, with significant attenuation at ±30° above 2 kHz.
- The slanted baffle mitigates some vertical phase issues but remains sensitive to listener height.
4. Impedance
- Below 450 Hz: 4 Ω (woofer range).
- Above 450 Hz: 8 Ω (midrange and tweeter).
- Compatible with most amplifiers, though the 4 Ω bass may require good current delivery.
Comparison to Popular Bookshelf Speakers in the $200–$1000 Range
To assess the competitiveness of this custom 3-way speaker, we compare it to five popular bookshelf speakers: the Polk Audio Signature Elite ES15, ELAC Debut B6.2, Klipsch R-51M, KEF Q150, and Triangle Borea BR03. These models are well-regarded for their balance of sound quality and value. The comparison includes frequency response, sensitivity, power handling, impedance, configuration, price, and—crucially—horizontal and vertical dispersion to evaluate sound distribution.Comparison Table
| Speaker Model | Frequency Response | Sensitivity | Power Handling | Impedance | Configuration | Horizontal Dispersion | Vertical Dispersion | Price (approx.) |
|---|---|---|---|---|---|---|---|---|
| Designed Speaker | 34 Hz – 20 kHz (±3 dB) | 86.5–87 dB | 100W RMS | 4Ω (<450 Hz), 8Ω (>450 Hz) | 3-way | ~90° at 1 kHz, ~60° at 10 kHz | ~40° at 1 kHz, ~30° at 10 kHz | $372 |
| Polk Audio Signature Elite ES15 | ~50 Hz – 20 kHz* | ~88 dB* | N/A | 8Ω* | 2-way | ~90° at 1 kHz, ~60° at 10 kHz* | ~40° at 1 kHz, ~30° at 10 kHz* | $250–$300 |
| ELAC Debut B6.2 | 44 Hz – 20 kHz | 87 dB | 30–120W | 6Ω | 2-way | ~90° at 1 kHz, ~60° at 10 kHz* | ~40° at 1 kHz, ~30° at 10 kHz* | $300 |
| Klipsch R-51M | 62 Hz – 21 kHz | 93 dB | 85W RMS | 8Ω | 2-way | ~90° at 1 kHz, ~60° at 10 kHz (horn-loaded) | ~40° at 1 kHz, ~30° at 10 kHz | $250 |
| KEF Q150 | 51 Hz – 28 kHz | 86 dB | 10–100W | 8Ω | 2-way (Uni-Q) | ~90° at 1 kHz, ~90° at 10 kHz (coaxial) | ~90° at 1 kHz, ~90° at 10 kHz (coaxial) | $500 |
| Triangle Borea BR03 | ~45 Hz – 20 kHz* | 87.3 dB | 30–120W | 8Ω* | 2-way | ~90° at 1 kHz, ~60° at 10 kHz* | ~40° at 1 kHz, ~30° at 10 kHz* | $500–$600 |
*Estimated based on typical specifications w
Performance Analysis
Bass Extension (Frequency Response)
The designed speaker’s 34 Hz bass extension outperforms all comparison models. The ELAC B6.2 (44 Hz) and Triangle BR03 (~45 Hz) are closest, while the Polk ES15 (~50 Hz), KEF Q150 (51 Hz), and Klipsch R-51M (62 Hz) have higher roll-off points, making the designed speaker better for deep bass without a subwoofer.Sensitivity
The Klipsch R-51M leads with 93 dB, ideal for louder output with less power. The designed speaker’s 86.5–87 dB aligns with the ELAC B6.2 (87 dB), KEF Q150 (86 dB), and Triangle BR03 (87.3 dB), while the Polk ES15 is estimated at ~88 dB. It’s sufficient for most home setups.Power Handling
The designed speaker’s 100W RMS matches or exceeds most competitors. The Klipsch R-51M is rated at 85W RMS, and the KEF Q150 handles up to 100W, while the ELAC B6.2 and Triangle BR03 support up to 120W amplifiers.Impedance
The designed speaker’s hybrid impedance (4 Ω below 450 Hz, 8 Ω above) may demand an amplifier capable of handling 4 Ω loads, unlike the 8 Ω or 6 Ω ratings of the comparison models, which are easier to drive.Configuration
The 3-way design provides dedicated drivers for bass, midrange, and treble, potentially offering better frequency separation than the 2-way configurations of the comparison speakers.Dispersion (Horizontal and Vertical)
- Horizontal Dispersion: The designed speaker offers ~90° at 1 kHz, narrowing to ~60° at 10 kHz, similar to most 2-way speakers like the Polk ES15, ELAC B6.2, and Triangle BR03. The Klipsch R-51M’s horn-loaded tweeter may enhance high-frequency dispersion slightly. The KEF Q150, with its coaxial Uni-Q driver, maintains ~90° across frequencies, offering a wider sweet spot.
- Vertical Dispersion: The designed speaker’s vertical dispersion is ~40° at 1 kHz and ~30° at 10 kHz, typical for vertically aligned drivers. The KEF Q150 excels with ~90° vertical dispersion due to its coaxial design, making it less sensitive to listener height. The other models align with the designed speaker’s narrower vertical spread. The slanted baffle in the designed speaker reduces some vertical phase issues, but listener height remains a factor.
Price
At $372 per pair, the designed speaker competes with the Polk ES15 ($250–$300), ELAC B6.2 ($300), and Klipsch R-51M ($250), while undercutting the KEF Q150 ($500) and Triangle BR03 ($500–$600). Its DIY cost excludes labor, enhancing its value.Conclusion
This custom 3-way bookshelf speaker pair delivers exceptional performance for its price, with superior bass extension (34 Hz), a flat frequency response, and a 3-way design enhancing midrange clarity. Its horizontal dispersion matches most competitors, while its narrower vertical dispersion requires careful positioning, unlike the KEF Q150’s coaxial advantage. Compared to models like the Polk ES15, ELAC B6.2, and Klipsch R-51M, it offers better low-end performance and detail, and its price undercuts higher-end options like the KEF Q150 and Triangle BR03. For DIY enthusiasts seeking high-fidelity sound on a budget, this design is a standout choice.How to repair/refresh this wood finish?
As part of my conversion, I want to refresh the finish on the original cabinet (the cherry part in this pic). There is no major damage, the only issues are:
The original finish is kind of satin laquer, with wood grain/texture slightly visible.
What is the best way to deal with these two issues? I want to completely remove the clouding and make the small scratches/dents disappear as far as possible.
- minor scratches and tiny dents in the finish
- large areas of sort of cloudy tint resulting from stupidly wiping the cabinet with a wet cloth that had a little PVA in it
The original finish is kind of satin laquer, with wood grain/texture slightly visible.
What is the best way to deal with these two issues? I want to completely remove the clouding and make the small scratches/dents disappear as far as possible.
Xmas Amp - Dibya's TDA7293 by Jhofland
Hi Folks,
Members Dibya and Jhofland have designed a new amp using the TDA7293 chip amp. I have not heard it myself, but I trust Dibya's ears when he says it sounds exceptional.
Dibya said that despite this chipamp sounding so womderful, it was surprising that there is not already an existing design on DIYA. So we teamed up with Jhofland who did the design and layout of a mono amp. Jhofland added a DC servo to control the offset and provided some regulated power for the opamp. The board is pretty compact and I am sure easy to build. The best part is that it's inexpensive. The full BOM from Mouser (shopping cart below) is only $26 per channel (not including the home made inductor using 18ga magnet wire wrapped 12 times around a AA battery as a mandrel).
Some of the notable mods developed by Dibya and perfected with Jhofland's help include:
The optimizations for the gain, bootstrap, and PSU decoupling were found using a CRO by Dibya. The lower gain setting was found by extensive listening tests.
Recommended PSU would be a 150VA 25v 0v 25v trafo with 15,000uF per rail for mono, or 300VA 25v 0v 25v with 20,000uF per rail for stereo. Note that if on-board DC servo is not used, then up to 35v 0v 35v trafo's can be used for +/-50v rails for the full 100w output power. However, that will require some really big heatsinks. It is much better to run no higher than +/-40v per Dibya's recommendation. Some recommendations for affordable trafos and heatsinks here.
Note that if populating the DC servo, C17 and C2 should be replaced with jumpers. The on-board voltage regulators are +/-40v max rails so please keep that in mind when choosing the PSU.
The design is free for your personal use and the Gerbers, BOM and schematics are below. Jhofland's designs are superb and I have enjoyed many of his creations. I have not yet built the verification board yet (still waiting for PCBs to arrive) so at this point, you would be building it at your own risk as a beta tester. However, it is quite a simple design and mostly follows the factory datasheet except for the DC offset servo.
If you don't want to order boards for yourself, I can provide them for cost of shipping. First come first serve 25 pairs of boards maximum. Please add your name to the free board interest list below and once we verify they work, I can order boards and get them out to you. This is a holiday special offer that will end by Jan 31, 2021. Boards will be 2oz copper HASL finish with green solder mask.
Special thanks to Jhofland for the wonerful design and layout, and to Dibya for the inspiration and for putting us on this path to inexpensive yet great sound.
Happy holidays and enjoy!
Closeup of pdf schematic, main amp portion (note that R15 should be replaced by 47k or as low as 10k to get better zero DC offset tracking and C1 should be closer to 4.7uF to get the deepest bass extension):
Closeup of pdf schematic, opamp PSU portion:
Output stage topology from datasheet. Note that it looks like a quasi-complementary topology, could this be the secret to the great sound?:
PCB renders:
Mouser Shopping Cart:
Mouser Electronics
#### TDA7293 Xmas Amp Free PCB Interest List (maximum 2 boards please) ####
for example:
Name / Country
-----------------------------
xrk971 / USA
Here is the thread for handling the logistics of the giveaway.
https://www.diyaudio.com/forums/swa...3-xmas-amp-jhofland-giveaway.html#post6487628
Edit Jan. 13, 2021: Final design files (Gerbers, Schematic, BOM) are here.
Edit Feb 13, 2021 - cleaned up the grounding on the measurement and here is 10W case, THD is 0.0014%:
Here is 40W case, THD is 0.005%:
My implementation using surplus Dell CPU coolers:
Members Dibya and Jhofland have designed a new amp using the TDA7293 chip amp. I have not heard it myself, but I trust Dibya's ears when he says it sounds exceptional.
Dibya said that despite this chipamp sounding so womderful, it was surprising that there is not already an existing design on DIYA. So we teamed up with Jhofland who did the design and layout of a mono amp. Jhofland added a DC servo to control the offset and provided some regulated power for the opamp. The board is pretty compact and I am sure easy to build. The best part is that it's inexpensive. The full BOM from Mouser (shopping cart below) is only $26 per channel (not including the home made inductor using 18ga magnet wire wrapped 12 times around a AA battery as a mandrel).
Some of the notable mods developed by Dibya and perfected with Jhofland's help include:
- Reduced gain of 28db for improved sound quality (default is 32dB)
- Improved feedback optimizations for better LF & HF sound quality
- DC offset servo for improved LF performance
- Addition of Thiel Network for improved stability
- Tweaks for improved HF response
- Bootstrap mod for improved bass response
- Optimized values of decoupling caps for best midrange sound quality
The optimizations for the gain, bootstrap, and PSU decoupling were found using a CRO by Dibya. The lower gain setting was found by extensive listening tests.
Recommended PSU would be a 150VA 25v 0v 25v trafo with 15,000uF per rail for mono, or 300VA 25v 0v 25v with 20,000uF per rail for stereo. Note that if on-board DC servo is not used, then up to 35v 0v 35v trafo's can be used for +/-50v rails for the full 100w output power. However, that will require some really big heatsinks. It is much better to run no higher than +/-40v per Dibya's recommendation. Some recommendations for affordable trafos and heatsinks here.
Note that if populating the DC servo, C17 and C2 should be replaced with jumpers. The on-board voltage regulators are +/-40v max rails so please keep that in mind when choosing the PSU.
The design is free for your personal use and the Gerbers, BOM and schematics are below. Jhofland's designs are superb and I have enjoyed many of his creations. I have not yet built the verification board yet (still waiting for PCBs to arrive) so at this point, you would be building it at your own risk as a beta tester. However, it is quite a simple design and mostly follows the factory datasheet except for the DC offset servo.
If you don't want to order boards for yourself, I can provide them for cost of shipping. First come first serve 25 pairs of boards maximum. Please add your name to the free board interest list below and once we verify they work, I can order boards and get them out to you. This is a holiday special offer that will end by Jan 31, 2021. Boards will be 2oz copper HASL finish with green solder mask.
Special thanks to Jhofland for the wonerful design and layout, and to Dibya for the inspiration and for putting us on this path to inexpensive yet great sound.
Happy holidays and enjoy!
Closeup of pdf schematic, main amp portion (note that R15 should be replaced by 47k or as low as 10k to get better zero DC offset tracking and C1 should be closer to 4.7uF to get the deepest bass extension):
Closeup of pdf schematic, opamp PSU portion:
Output stage topology from datasheet. Note that it looks like a quasi-complementary topology, could this be the secret to the great sound?:
PCB renders:
Mouser Shopping Cart:
Mouser Electronics
#### TDA7293 Xmas Amp Free PCB Interest List (maximum 2 boards please) ####
for example:
Name / Country
-----------------------------
xrk971 / USA
Here is the thread for handling the logistics of the giveaway.
https://www.diyaudio.com/forums/swa...3-xmas-amp-jhofland-giveaway.html#post6487628
Edit Jan. 13, 2021: Final design files (Gerbers, Schematic, BOM) are here.
Edit Feb 13, 2021 - cleaned up the grounding on the measurement and here is 10W case, THD is 0.0014%:
Here is 40W case, THD is 0.005%:
My implementation using surplus Dell CPU coolers:
Attachments
-
TDA7293_ Schematic_12_06_20.pdf
-
TDA7293-Amp-Rev1.1-Schematic-main-amp.jpg -
TDA7293-Amp-Rev1.1-Schematic-opamp-psu.jpg -
TDA7293-datasheet-output-stage-detail.jpg -
TDA7293-Rev2-Render-Top.png -
TDA7293_amp_BOM_Dec6_2020.zip
-
Gerbers_TDA7293_ver1_12_06_20.zip
-
TDA7293-Rev2-Render-Bottom.png -
Dibya-8ch-TDA7293.jpg
Power amp measurement system
- By LKA
- Equipment & Tools
- 49 Replies
I decided to upgrade my poweramp measurement system.
The devices:
1/ ultra low distortion sine wave oscillator - I bought Victor's 1k and 10k
2/ dummy load - designed and made by me
3/ passive voltage divider - under development
4/ passive notch filter- schematic Victor, made by me
5/ post notch buffer - under development - powered by two 9V battery
6/ PC sound cards I have
- ESI Juli@ PCI
- Asus Xonar STX II
- X-Fi USB HD modded Improving A/D perfromance of Sound Balster X-fi Music (SB1240) - and a Puzzle!!! - diyAudio
the dummy load
The devices:
1/ ultra low distortion sine wave oscillator - I bought Victor's 1k and 10k
2/ dummy load - designed and made by me
3/ passive voltage divider - under development
4/ passive notch filter- schematic Victor, made by me
5/ post notch buffer - under development - powered by two 9V battery
6/ PC sound cards I have
- ESI Juli@ PCI
- Asus Xonar STX II
- X-Fi USB HD modded Improving A/D perfromance of Sound Balster X-fi Music (SB1240) - and a Puzzle!!! - diyAudio
the dummy load
Attachments
B1 preamp build thread
Hello!
I recently inherited a bunch of stuff from a fellow DIYer, and one of the things was a nice chassis suitable for a preamp or perhaps Chipamp with an outboard PSU. Discussions with other members, as well as a healthy dose of curiosity led me to choose the B1. It went together very easily and quickly. Here is the log of that build.
The finished product. It sounds fantastic!
But how did I get there? well...
When doing a project like this, the easiest place to begin (for me, anyway...) is the mechanical. Drilling, hardware, things that touch the chassis. Not a lot of drilling was involved, the power inlet module was pre-cut, so I added the holes for the RCA jacks and the screws for the circuit boards and transformer.
This is just placing the various boards and transformer in place to see how things will fit. The blue board shown in this photo is actually a dual-rail PSU PSB from Peter Daniel, the single rail is exactly half of it.
This is a really nice Goldpoint switch and series stepped attenuator made from a Elna 24 pole switch and a bunch of Holco resistors. It's all wired up because it was salvaged from a different project.
You will notice in this photo that the grounds of the inputs are wired together. This is for two reasons... firstly, the RCA jacks all float on the chassis - the shoulder washers isolate the jack from the chassis. Also, the PassDIY circuit board has a pad for ground on both left and right... so there will be wire connected to one of these negative tabs to the PCB pad.
A well-stocked junk box to the rescue!! This switch is the one I had to use in the end... the Goldpoint that was on the harness with the attenuator had a shaft that was just too short to use with the knobs on the chassis. This switch was bought only a few weeks ago as I was perusing through the local surplus store and saw this switch perfect for a preamp. Luck favors the prepared!
So here are the selector and the attenuator mounted, and the PCB with some of the wires soldered in place. In order to keep the wires as short as comfortable, it is prudent to solder all of one edge in place, and then you only have to do the other edge in place. if you do this, make sure that your wires are at least a couple of inches longer than you know you will need. Too long you can trim, but too short is a pain in the backside!
The wiring continues.
I originally envisioned the preamp board turned the other way, to keep the leads from the RCA jacks shorter. The size of the attenuator happened to get in the way of the black electrolytic caps, so it got turned 180deg.
Here is the single-rail universal power supply PCB from Peter Daniel. It's a very nice board, with the ability to choose 2- or 3- pin diodes (or none at all), many different lead spacings on the filter capacitors, and either a LT1085 or LM317 regulator. Shown here are MUR860 diodes and a LM317 regulator.
When I first fired this up I couldn't adjust it to get more than about 7.5-8 volts on the outputs... I was slightly confused, and knowing that just thinking about it wouldn't fix anything, decided to measure the components... It turned out that I grabbed a 240K ohm resistor when I need a 240R... 😀 Anyway, I didn't have anything close to 240, but I happened to have two 150R that are now placed in series in that position, and it works very well now! The range of adjustment is about 17-25 volts, and have it set at 19.5v
This is the last check of the wiring to see where the power supply wires will place.
Just to recap, the black and blue are signal input, switching and attenuation, the red/white is from psu board to preamp board, and the blue/blue-white, orange/orange-white is the output.
And here it is complete - the power inlet module is installed and above the transformer, the yellow/black leads are the secondary of the transformer.
This was a very easy and rewarding project. I cannot express enough gratitude to both Nelson Pass (you rock!) and Peter Daniels (you also rock!) for making the circuit and and the PSU board. Although something like this could be very easily made on perfboard (and I thought quite seriously about it) any project is greatly simplified by good circuit boards!
I recently inherited a bunch of stuff from a fellow DIYer, and one of the things was a nice chassis suitable for a preamp or perhaps Chipamp with an outboard PSU. Discussions with other members, as well as a healthy dose of curiosity led me to choose the B1. It went together very easily and quickly. Here is the log of that build.
The finished product. It sounds fantastic!
But how did I get there? well...
When doing a project like this, the easiest place to begin (for me, anyway...) is the mechanical. Drilling, hardware, things that touch the chassis. Not a lot of drilling was involved, the power inlet module was pre-cut, so I added the holes for the RCA jacks and the screws for the circuit boards and transformer.
This is just placing the various boards and transformer in place to see how things will fit. The blue board shown in this photo is actually a dual-rail PSU PSB from Peter Daniel, the single rail is exactly half of it.
This is a really nice Goldpoint switch and series stepped attenuator made from a Elna 24 pole switch and a bunch of Holco resistors. It's all wired up because it was salvaged from a different project.
You will notice in this photo that the grounds of the inputs are wired together. This is for two reasons... firstly, the RCA jacks all float on the chassis - the shoulder washers isolate the jack from the chassis. Also, the PassDIY circuit board has a pad for ground on both left and right... so there will be wire connected to one of these negative tabs to the PCB pad.
A well-stocked junk box to the rescue!! This switch is the one I had to use in the end... the Goldpoint that was on the harness with the attenuator had a shaft that was just too short to use with the knobs on the chassis. This switch was bought only a few weeks ago as I was perusing through the local surplus store and saw this switch perfect for a preamp. Luck favors the prepared!
So here are the selector and the attenuator mounted, and the PCB with some of the wires soldered in place. In order to keep the wires as short as comfortable, it is prudent to solder all of one edge in place, and then you only have to do the other edge in place. if you do this, make sure that your wires are at least a couple of inches longer than you know you will need. Too long you can trim, but too short is a pain in the backside!
The wiring continues.
I originally envisioned the preamp board turned the other way, to keep the leads from the RCA jacks shorter. The size of the attenuator happened to get in the way of the black electrolytic caps, so it got turned 180deg.
Here is the single-rail universal power supply PCB from Peter Daniel. It's a very nice board, with the ability to choose 2- or 3- pin diodes (or none at all), many different lead spacings on the filter capacitors, and either a LT1085 or LM317 regulator. Shown here are MUR860 diodes and a LM317 regulator.
When I first fired this up I couldn't adjust it to get more than about 7.5-8 volts on the outputs... I was slightly confused, and knowing that just thinking about it wouldn't fix anything, decided to measure the components... It turned out that I grabbed a 240K ohm resistor when I need a 240R... 😀 Anyway, I didn't have anything close to 240, but I happened to have two 150R that are now placed in series in that position, and it works very well now! The range of adjustment is about 17-25 volts, and have it set at 19.5v
This is the last check of the wiring to see where the power supply wires will place.
Just to recap, the black and blue are signal input, switching and attenuation, the red/white is from psu board to preamp board, and the blue/blue-white, orange/orange-white is the output.
And here it is complete - the power inlet module is installed and above the transformer, the yellow/black leads are the secondary of the transformer.
This was a very easy and rewarding project. I cannot express enough gratitude to both Nelson Pass (you rock!) and Peter Daniels (you also rock!) for making the circuit and and the PSU board. Although something like this could be very easily made on perfboard (and I thought quite seriously about it) any project is greatly simplified by good circuit boards!
Attachments
Replacement capacitor
- By Tetsuo1981
- Parts
- 14 Replies
Can I swap this gold capacitor with with the one in the 2nd picture safely?
Discussion: Padding Down Mid/Tweeter VS Multiple Woofer/Mid to match Tweeter
I do not see this discussed to any extent so I'd like to open this up.
As we all know, different drivers have different sensitivities. As far as I can tell there are two solutions to this issue if you plan to design an accurate loudspeaker:
1. Pad down the higher sensitivity drivers to match your lowest sensitivity driver
2. Increase the number of lower sensitivity drivers until they match the higher sensitivity drivers
I see the pro/cons of these options as thus:
Option 1
Pros
1. Cheaper: Less drivers means lower cost
2. Smaller: More compact for space savings
3. Simplicity: Less drivers means the design and the response is simpler. It is easier to take measurements.
Cons
1. Loss of sensitivity: Your system sensitivity will only be as high as your lowest driver
2. Potential cost of amplifier: You will need so spend more on your amplifier as your system will be harder to drive
3. Less amplifier options: Depending on your final sensitivity, you selection of amplifier may be cut down significantly
4. Less woofer/mid options if you need a higher sensitivity system
Option 2
Pros
1. Higher sensitivity: you would be able to use whatever amplifier you wanted with a high sensitivity system
2. Driver work: The amount of work the lower drivers will have to perform will but significantly cut down. Your woofers will handle much more power before hitting XMAX
3. Power threshold: The system should be able to handle a lot more power before distortion
4. Less amplifier distortion, less woofer distortion
5. With more driver in vertical axis you should be able to significantly reduce vertical cancellations which should better fill a room
6. It will look super impressive: No doubt, a loudspeaker using redundant drivers that goes up to the ceiling looks far more impressive.
7. You can use any woofers you want as sensitivity can be accounted for using multiple drivers.
Cons
1. Much more expensive: You will need multiple drivers, however, your crossover costs should remain the same
2. More complex build: The enclosure will be much more complex to design and build
3. More complex measurements: I have not personally ever measured redundant drivers but I imagine it isn't as cut and dry as measuring just one.
4. It will take up more space: It is going to be much larger. Geometry is geometry.
I'd like to hear all of your thoughts on these two different approaches as I am considering using multiple drivers to up my sensitivity on my next build. I have an example below that is really a hybrid of the two
I will also throw into this mix a discussion of low frequency sensitivity. Most of us are trying to boost the low frequencies using multiple drivers. Tweeters play loudly, woofers do not. I have heard that what matters most for the low end is cone area and power. The driver sensitivity doesn't matter below 150 hz or so. I do not know if this is true. It does not seem like it is true. Then again, I do not know exactly how sensitivity is measured. I hear it is playing a 1000hz tone with 1 watt then measuring the decibels. Due to peaks, cone resonances, and driver frequency response I would think this would not be a perfectly accurate measurement for all drivers. If someone knows, please post that information as I feel it is critical to this discussion.
Please ignore any errors on this XO and design. It is just an example for flare that I tossed together in a hurry.
As we all know, different drivers have different sensitivities. As far as I can tell there are two solutions to this issue if you plan to design an accurate loudspeaker:
1. Pad down the higher sensitivity drivers to match your lowest sensitivity driver
2. Increase the number of lower sensitivity drivers until they match the higher sensitivity drivers
I see the pro/cons of these options as thus:
Option 1
Pros
1. Cheaper: Less drivers means lower cost
2. Smaller: More compact for space savings
3. Simplicity: Less drivers means the design and the response is simpler. It is easier to take measurements.
Cons
1. Loss of sensitivity: Your system sensitivity will only be as high as your lowest driver
2. Potential cost of amplifier: You will need so spend more on your amplifier as your system will be harder to drive
3. Less amplifier options: Depending on your final sensitivity, you selection of amplifier may be cut down significantly
4. Less woofer/mid options if you need a higher sensitivity system
Option 2
Pros
1. Higher sensitivity: you would be able to use whatever amplifier you wanted with a high sensitivity system
2. Driver work: The amount of work the lower drivers will have to perform will but significantly cut down. Your woofers will handle much more power before hitting XMAX
3. Power threshold: The system should be able to handle a lot more power before distortion
4. Less amplifier distortion, less woofer distortion
5. With more driver in vertical axis you should be able to significantly reduce vertical cancellations which should better fill a room
6. It will look super impressive: No doubt, a loudspeaker using redundant drivers that goes up to the ceiling looks far more impressive.
7. You can use any woofers you want as sensitivity can be accounted for using multiple drivers.
Cons
1. Much more expensive: You will need multiple drivers, however, your crossover costs should remain the same
2. More complex build: The enclosure will be much more complex to design and build
3. More complex measurements: I have not personally ever measured redundant drivers but I imagine it isn't as cut and dry as measuring just one.
4. It will take up more space: It is going to be much larger. Geometry is geometry.
I'd like to hear all of your thoughts on these two different approaches as I am considering using multiple drivers to up my sensitivity on my next build. I have an example below that is really a hybrid of the two
I will also throw into this mix a discussion of low frequency sensitivity. Most of us are trying to boost the low frequencies using multiple drivers. Tweeters play loudly, woofers do not. I have heard that what matters most for the low end is cone area and power. The driver sensitivity doesn't matter below 150 hz or so. I do not know if this is true. It does not seem like it is true. Then again, I do not know exactly how sensitivity is measured. I hear it is playing a 1000hz tone with 1 watt then measuring the decibels. Due to peaks, cone resonances, and driver frequency response I would think this would not be a perfectly accurate measurement for all drivers. If someone knows, please post that information as I feel it is critical to this discussion.
Please ignore any errors on this XO and design. It is just an example for flare that I tossed together in a hurry.
Help with repairing a Memphis Audio PR1x1000? How to check the transformer, is it shorted?
Hello, I am currently trying to repair a Memphis Audio Pr1x1000 amp. I think I have narrowed down the problem to a short somewhere near the transformer, (I think). And I am trying to rule out the transformer as the problem, but I dont exactly know how to test the transformer, I am getting a couple of shorts on the transformer, but I dont know if that is normal or not, I can leave a photo of what is shorted together. Can someone help me figure out what should, and shouldnt be "shorted" on the transformer?
Some things I have done:
I thought it might be a mosfet/transistor, but I pulled all the transistors, and the short was still there, and all the transistors seem to be in working condition, (from what I can tell)
I used some IPA around the board to check for hot spots, and two diodes and a small capacitor were getting hot when the amp was powered on, so I pulled them, and the transformer seems to be shorted still, unless what Im seeing continuity on is normal. (You should be able to see the diodes in the photo, they are the ones slightly askew as I put them back on the board)
I also found an IC that was getting warm, a IRS2092S (op amp?) but when I pulled it, the transformer still has those "shorts"
I tried hooking my multimeter in continuity mode to the "shorts" on the transformer, and wiggling wires to see if it would stop or change, but it didnt
Idk, but at this point im lost, and just wondering how to make sure my transformer is good, or what else I should be checking.
Any help is much appreciated.
Some things I have done:
I thought it might be a mosfet/transistor, but I pulled all the transistors, and the short was still there, and all the transistors seem to be in working condition, (from what I can tell)
I used some IPA around the board to check for hot spots, and two diodes and a small capacitor were getting hot when the amp was powered on, so I pulled them, and the transformer seems to be shorted still, unless what Im seeing continuity on is normal. (You should be able to see the diodes in the photo, they are the ones slightly askew as I put them back on the board)
I also found an IC that was getting warm, a IRS2092S (op amp?) but when I pulled it, the transformer still has those "shorts"
I tried hooking my multimeter in continuity mode to the "shorts" on the transformer, and wiggling wires to see if it would stop or change, but it didnt
Idk, but at this point im lost, and just wondering how to make sure my transformer is good, or what else I should be checking.
Any help is much appreciated.
Value of old paper capacitor by color codes?
I'd like to replace this old capacitor, but before clipping it out to measure it, could anyone help me figure out the value by the color code?
One problem is that I don't know which end of the capacitor has the 'first' color band. Does it start with green? Or does it start with blue?
Is the thicker green band the voltage indicator? If so, I guess that means 600V (DC).
After that, I get:
Grey = 8
Orange = 3
White = 9
And for tolerance,
Blue = 6%
That doesn't make sense to me. I must be reading this wrong. Can anyone help me understand how the manufacturers color coded these old capacitors? Thanks...
One problem is that I don't know which end of the capacitor has the 'first' color band. Does it start with green? Or does it start with blue?
Is the thicker green band the voltage indicator? If so, I guess that means 600V (DC).
After that, I get:
Grey = 8
Orange = 3
White = 9
And for tolerance,
Blue = 6%
That doesn't make sense to me. I must be reading this wrong. Can anyone help me understand how the manufacturers color coded these old capacitors? Thanks...
Audio Innovations Alto amp overheating
- Solid State
- 10 Replies
I acquired an Alto amp last October, and it has run fine until now, apart from a loud buzz which was tracked down to the volume pot's earthing connection. Loosening the mounting nut stopped that. But now the right channel has started to run away, thermally. I have measured everything I can with a multimeter, comparing left and right channels, and have not managed to find any differences so far. This is unpowered, as I only get 20-30 seconds before the fuse on the left channel blows.
I have an infrared thermometer, so I can run it until it gets to about 30 degrees and then power off. The left channel barely warms. Looking at the instructions, I get half PSU voltage on R21/R22 as I should. I haven't yet checked across R21/R22 for 30mV.
I am fine building amps, but not so hot with fault finding, as I can follow a schematic without fully understanding exactly how it works. Hands better than brain! And I have all the transistors and diodes if I need to replace them. I haven't removed any components yet to fully check them.
What I need is help with understanding which components are the most likely to be causing the problem. I can replace any I need to, I can reflow solder joints, etc.
I have an infrared thermometer, so I can run it until it gets to about 30 degrees and then power off. The left channel barely warms. Looking at the instructions, I get half PSU voltage on R21/R22 as I should. I haven't yet checked across R21/R22 for 30mV.
I am fine building amps, but not so hot with fault finding, as I can follow a schematic without fully understanding exactly how it works. Hands better than brain! And I have all the transistors and diodes if I need to replace them. I haven't removed any components yet to fully check them.
What I need is help with understanding which components are the most likely to be causing the problem. I can replace any I need to, I can reflow solder joints, etc.
LT3081 PNP pass transistor ltspice simulation file problem?
- By nhs0124
- Power Supplies
- 0 Replies
I need to extend the current of LT3081 to 3.5A using a PNP pass transistor, but there is a problem in the LTspice simulation and the transient stability simulation cannot be performed. Can you provide a simulation file that can be run?
Sudden current draw problem from DC-DC converter
- By HHhelpneeded
- Electronic Design
- 4 Replies
Hello again, I made a little electronic gadget for my guitar pedals, let me explain my little gadget first. It's a 5volts 10k mah powerbank tied to a little dc-dc conventer that rated 1.5v & 36v 3amps
When I daisy chain it to few pedals at 9 volts which drawing like 300ma at total, it works great, problem arises when I chain it for like 5+ pedals.
If all pedals switched on, powerbank and all the leds of pedals flashes rapidly 3 times and I lose the power and powerbank turns off.
Then I tried something different, I changed my dc-dc's output to 18volts and plugged in to a power supply that designed for pedals, samething happened again all leds including power supply's flashed rapidly but weaker for 3 times then powerbank shutdown itself again...
My question is how can I make this setup to engage and keep my power supply running, because I have no problem powering and cranking my Yamaha Thr10c amp. It has a power adapter that rated 15v 3A. Somehow I just can't draw enough power for 9V 1A or just the power supply itself which is like 18V 200ma without anything attached.
Any help would be great !
Edit: changed my question
When I daisy chain it to few pedals at 9 volts which drawing like 300ma at total, it works great, problem arises when I chain it for like 5+ pedals.
If all pedals switched on, powerbank and all the leds of pedals flashes rapidly 3 times and I lose the power and powerbank turns off.
Then I tried something different, I changed my dc-dc's output to 18volts and plugged in to a power supply that designed for pedals, samething happened again all leds including power supply's flashed rapidly but weaker for 3 times then powerbank shutdown itself again...
My question is how can I make this setup to engage and keep my power supply running, because I have no problem powering and cranking my Yamaha Thr10c amp. It has a power adapter that rated 15v 3A. Somehow I just can't draw enough power for 9V 1A or just the power supply itself which is like 18V 200ma without anything attached.
Any help would be great !
Edit: changed my question
The very free speaker! - Mount any number of drivers in any position I like, with any wiring method I like, without worrying about design theories!
- By nandappe
- Full Range
- 41 Replies
This is an enclosure that can be played with and tested in various ways (model : DDVP-1303-WHIM).
Recommended drivers are MarkAudio CHP90 mica, CHR90, Alpair10.3, and MAOP10.
In this case, I mounted the three CHP90 at A, C, and E in the drawing and parallel wired them.
It would be interesting to mount them in positions other than A-G, or to mount a tweeter on the upper side of A and a woofer on the lower side plate.
Recommended drivers are MarkAudio CHP90 mica, CHR90, Alpair10.3, and MAOP10.
In this case, I mounted the three CHP90 at A, C, and E in the drawing and parallel wired them.
It would be interesting to mount them in positions other than A-G, or to mount a tweeter on the upper side of A and a woofer on the lower side plate.
Attachments
For Sale Papst outer rotor capstan motor
- Swap Meet
- 0 Replies
The motor was meant to be used in professional studio tape recorders.
It has dual bronze sleeve bearings and a hard chrome plated capstan, long enough for one inch tape.
The capstan diameter measures .4775 inches which suggests 600 RPM for a tape speed of 15"per second. The second speed may be 1200 RPM.
The motor runs on 115VAC-60 Hz and it requires two capacitors, one for each speed.
To make sure it runs, I'll buy the two capacitors and include them in the sale.
I don't think the motor was ever used because there is no hint of tape oxide having rubbed off on the capstan. I think it was a sample motor from Papst to the Scully Recording Instruments Company.
As yet, I'll have to figure out the wire connections.
Thanks,
Ralf
It has dual bronze sleeve bearings and a hard chrome plated capstan, long enough for one inch tape.
The capstan diameter measures .4775 inches which suggests 600 RPM for a tape speed of 15"per second. The second speed may be 1200 RPM.
The motor runs on 115VAC-60 Hz and it requires two capacitors, one for each speed.
To make sure it runs, I'll buy the two capacitors and include them in the sale.
I don't think the motor was ever used because there is no hint of tape oxide having rubbed off on the capstan. I think it was a sample motor from Papst to the Scully Recording Instruments Company.
As yet, I'll have to figure out the wire connections.
Thanks,
Ralf
Single Ended: the pentode retaliation
- By zintolo
- Tubes / Valves
- 322 Replies
As a side thread from the original one for the Push-Pull ( Shunt Cascode Driver meets UNSET for Push-Pull ), I post here a preliminary version of a pentode-driving-a-pentode single ended amp with a DF of 8.6 (Zout is 0.93 Ohm considering 0.2 Ohm of secondary winding) without any gnfb, and capable of 30Wrms with 1.34% THD.
The driver is a pentode CCS loaded with a-g1 feedback, whilst the output is a pentode with a-g1 feedback plus the same amount of UL.
I've used this transformer as reference: TTG-KT88SE - Tube output UL transformer [3kOhm] KT88 / 300B SE - Shop Toroidy.pl
I can get 0.089% THD at 1 Wrms:
The driver is swinging 70Vpp at 0.015% THD:
I can get 0.32% THD at 10 Wrms:
The driver is swinging 220Vpp at 0.06% THD:
I can get 0.57% THD at 20 Wrms:
The driver is swinging 320Vpp at 0.12% THD:
I can get 1.34% THD at 30 Wrms:
The driver is swinging 400Vpp at 0.23% THD:
The driver is a pentode CCS loaded with a-g1 feedback, whilst the output is a pentode with a-g1 feedback plus the same amount of UL.
I've used this transformer as reference: TTG-KT88SE - Tube output UL transformer [3kOhm] KT88 / 300B SE - Shop Toroidy.pl
I can get 0.089% THD at 1 Wrms:
Code:
Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 3.959e+00 1.000e+00 -179.97° 0.00°
2 2.000e+03 3.508e-03 8.861e-04 -91.90° 88.07°
3 3.000e+03 3.851e-04 9.727e-05 -179.56° 0.42°
4 4.000e+03 2.383e-05 6.019e-06 13.08° 193.05°
5 5.000e+03 1.936e-05 4.890e-06 -0.11° 179.86°
6 6.000e+03 1.483e-05 3.747e-06 -0.20° 179.77°
7 7.000e+03 1.271e-05 3.211e-06 -0.19° 179.78°
8 8.000e+03 1.113e-05 2.812e-06 -0.17° 179.81°
9 9.000e+03 9.894e-06 2.499e-06 -0.15° 179.83°
10 1.000e+04 8.905e-06 2.249e-06 -0.13° 179.84°
Total Harmonic Distortion: 0.089152%(0.089155%)The driver is swinging 70Vpp at 0.015% THD:
Code:
Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 3.477e+01 1.000e+00 0.06° 0.00°
2 2.000e+03 5.256e-03 1.512e-04 -92.08° -92.14°
3 3.000e+03 6.492e-04 1.867e-05 2.58° 2.52°
4 4.000e+03 1.213e-04 3.487e-06 171.70° 171.64°
5 5.000e+03 9.866e-05 2.838e-06 -179.89° -179.95°
6 6.000e+03 8.013e-05 2.305e-06 -179.91° -179.97°
7 7.000e+03 6.867e-05 1.975e-06 -179.98° -180.05°
8 8.000e+03 6.009e-05 1.728e-06 -179.99° -180.05°
9 9.000e+03 5.342e-05 1.536e-06 -179.99° -180.05°
10 1.000e+04 4.808e-05 1.383e-06 -179.99° -180.05°
Total Harmonic Distortion: 0.015242%(0.015248%)I can get 0.32% THD at 10 Wrms:
Code:
Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 1.240e+01 1.000e+00 -179.97° 0.00°
2 2.000e+03 3.662e-02 2.953e-03 -92.57° 87.40°
3 3.000e+03 1.550e-02 1.250e-03 -179.47° 0.51°
4 4.000e+03 5.075e-04 4.092e-05 65.70° 245.67°
5 5.000e+03 7.392e-04 5.961e-05 1.79° 181.76°
6 6.000e+03 4.516e-05 3.642e-06 30.00° 209.97°
7 7.000e+03 6.843e-06 5.518e-07 -29.56° 150.41°
8 8.000e+03 4.013e-05 3.236e-06 -5.76° 174.22°
9 9.000e+03 3.700e-05 2.983e-06 -0.23° 179.75°
10 1.000e+04 3.099e-05 2.499e-06 0.04° 180.01°
Total Harmonic Distortion: 0.320767%(0.320768%)The driver is swinging 220Vpp at 0.06% THD:
Code:
Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 1.092e+02 1.000e+00 0.06° 0.00°
2 2.000e+03 5.965e-02 5.462e-04 -90.23° -90.29°
3 3.000e+03 2.869e-02 2.627e-04 2.11° 2.05°
4 4.000e+03 2.370e-03 2.170e-05 97.59° 97.53°
5 5.000e+03 1.253e-03 1.147e-05 -177.33° -177.39°
6 6.000e+03 2.699e-04 2.471e-06 -150.75° -150.81°
7 7.000e+03 1.610e-04 1.475e-06 178.82° 178.75°
8 8.000e+03 1.725e-04 1.580e-06 178.06° 178.00°
9 9.000e+03 1.551e-04 1.420e-06 -179.91° -179.97°
10 1.000e+04 1.384e-04 1.267e-06 -179.90° -179.97°
Total Harmonic Distortion: 0.060661%(0.060662%)I can get 0.57% THD at 20 Wrms:
Code:
Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 1.793e+01 1.000e+00 -179.98° 0.00°
2 2.000e+03 7.889e-02 4.399e-03 -93.30° 86.68°
3 3.000e+03 6.615e-02 3.689e-03 -179.21° 0.76°
4 4.000e+03 1.129e-03 6.297e-05 2.38° 182.36°
5 5.000e+03 7.964e-03 4.440e-04 2.39° 182.36°
6 6.000e+03 8.856e-04 4.938e-05 100.30° 280.27°
7 7.000e+03 1.101e-03 6.139e-05 -175.67° 4.31°
8 8.000e+03 2.349e-04 1.310e-05 -63.35° 116.63°
9 9.000e+03 2.290e-04 1.277e-05 3.30° 183.28°
10 1.000e+04 5.244e-05 2.924e-06 38.57° 218.55°
Total Harmonic Distortion: 0.575872%(0.575872%)The driver is swinging 320Vpp at 0.12% THD:
Code:
Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 1.587e+02 1.000e+00 0.06° 0.00°
2 2.000e+03 1.582e-01 9.970e-04 -90.08° -90.14°
3 3.000e+03 1.109e-01 6.988e-04 2.11° 2.05°
4 4.000e+03 1.605e-02 1.012e-04 90.48° 90.42°
5 5.000e+03 9.257e-03 5.834e-05 -176.41° -176.47°
6 6.000e+03 1.999e-03 1.260e-05 -101.79° -101.85°
7 7.000e+03 5.240e-04 3.302e-06 10.34° 10.28°
8 8.000e+03 2.831e-04 1.785e-06 136.14° 136.08°
9 9.000e+03 2.713e-04 1.710e-06 -176.22° -176.28°
10 1.000e+04 1.879e-04 1.184e-06 -174.49° -174.55°
Total Harmonic Distortion: 0.122318%(0.122318%)I can get 1.34% THD at 30 Wrms:
Code:
Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 2.211e+01 1.000e+00 -179.98° 0.00°
2 2.000e+03 5.387e-02 2.436e-03 -100.01° 79.97°
3 3.000e+03 2.631e-01 1.190e-02 -179.54° 0.44°
4 4.000e+03 5.724e-02 2.589e-03 -87.39° 92.59°
5 5.000e+03 8.979e-02 4.061e-03 -0.36° 179.62°
6 6.000e+03 4.086e-02 1.848e-03 88.38° 268.36°
7 7.000e+03 4.102e-02 1.855e-03 176.90° 356.88°
8 8.000e+03 2.481e-02 1.122e-03 -95.10° 84.88°
9 9.000e+03 2.127e-02 9.618e-04 -6.34° 173.63°
10 1.000e+04 1.379e-02 6.236e-04 81.49° 261.47°
Total Harmonic Distortion: 1.342064%(1.344007%)The driver is swinging 400Vpp at 0.23% THD:
Code:
Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 1.980e+02 1.000e+00 0.06° 0.00°
2 2.000e+03 3.429e-01 1.732e-03 -90.26° -90.32°
3 3.000e+03 2.900e-01 1.465e-03 2.37° 2.31°
4 4.000e+03 6.541e-02 3.304e-04 88.28° 88.22°
5 5.000e+03 4.225e-02 2.134e-04 -174.48° -174.54°
6 6.000e+03 1.313e-02 6.633e-05 -97.64° -97.70°
7 7.000e+03 6.336e-03 3.200e-05 15.17° 15.12°
8 8.000e+03 2.241e-03 1.132e-05 78.78° 78.72°
9 9.000e+03 1.403e-03 7.084e-06 -148.60° -148.65°
10 1.000e+04 6.102e-04 3.082e-06 -145.97° -146.03°
Total Harmonic Distortion: 0.230306%(0.230306%)Attachments
Simulation of a 3-way speaker with a cardioid pattern
Hello everyone, I am trying to run simulations in Vituix, with the aim of creating a 3-way speaker with a cardioid pattern. I started by tracing the speakers from the manufacturers' websites, then applied the low-frequency loading and baffle diffraction using the various tools that Vituix offers. My goal is to replicate the speaker to see if I can achieve reliable simulations with what I have designed and measured.
I will post a couple of graphs to share the simulation results and perhaps get suggestions for improving the whole setup.
The speaker will be a stand-mounted design, with dimensions of approximately 40/45cm in height, 35cm in depth, and 20cm in width. The tweeter and midwoofer will be placed on the front panel axis, while the two subwoofers will be positioned on the two side panels.
The crossover will be active, and the goal of the project, in addition to evaluating the quality of the simulation, will be to attempt to simulate an active cardioid system using the two side subwoofers.
Many thanks
Stefano
I will post a couple of graphs to share the simulation results and perhaps get suggestions for improving the whole setup.
The speaker will be a stand-mounted design, with dimensions of approximately 40/45cm in height, 35cm in depth, and 20cm in width. The tweeter and midwoofer will be placed on the front panel axis, while the two subwoofers will be positioned on the two side panels.
The crossover will be active, and the goal of the project, in addition to evaluating the quality of the simulation, will be to attempt to simulate an active cardioid system using the two side subwoofers.
Many thanks
Stefano
Wharfedale Triton crossover
I recently purchased some Wharfedale Triton speakers off eBay, with the intention of refurbishing them as a learning exercise. Essentially a practice pair of speakers, to learn how to clean the grille cloth, rewire and re-cap, that kind of thing. They came with a captive speaker cable that was terminated with a two pin DIN plug. Without thinking, I just chopped those off, as the little amplifier I use to test things only takes bare wire. I naively assumed that there would be some +ve / -ve type marking on the crossover circuit board inside, which it turns out there isn’t.
Here's the speakers in question:
A top view of the crossover, note that two of the inductors are missing any indication of value:
A mirrored view of the bottom of the crossover after I'd de-soldered all the leads:
I took some photos and attempted to try and understand the circuit, so I could determine the correct pins to wire up to some proper terminal posts. I started on a whiteboard, then tried to convert that into a “proper” circuit diagram. I’m new to all of this kind of thing, and am not sure that I’ve used all the correct symbols and terminology on the diagram; I would welcome some feedback on that.
My whiteboard circuit:
And the resulting circuit diagram:
Could someone please confirm whether my circuit diagram is accurate…? Specifically, I would like to verify that I have correctly identified the positive and negative input terminals on the circuit board. That would be the right most tab being the positive input, and the one to it's left, being the negative input.
Cheers,
Bob.
Here's the speakers in question:
A top view of the crossover, note that two of the inductors are missing any indication of value:
A mirrored view of the bottom of the crossover after I'd de-soldered all the leads:
I took some photos and attempted to try and understand the circuit, so I could determine the correct pins to wire up to some proper terminal posts. I started on a whiteboard, then tried to convert that into a “proper” circuit diagram. I’m new to all of this kind of thing, and am not sure that I’ve used all the correct symbols and terminology on the diagram; I would welcome some feedback on that.
My whiteboard circuit:
And the resulting circuit diagram:
Could someone please confirm whether my circuit diagram is accurate…? Specifically, I would like to verify that I have correctly identified the positive and negative input terminals on the circuit board. That would be the right most tab being the positive input, and the one to it's left, being the negative input.
Cheers,
Bob.
![PXL_20250325_202858459.RAW-01.MP.COVER[1].jpg](/community/data/attachments/1348/1348055-09583308872285fe6518e5759550b66f.jpg?hash=dWEA0eTIVL)