Aikido Stereo Octal PCB +
NOS. PCB; Russian K42Y PIO .47uF 500 VDC (2), RTI 1uF 400VDC (2) coupling capacitors; Wima MKP10 .68uF & .33uF and 6 electrolytic supporting and power supply capacitors; double sided tape.
$60 plus shipping.
$60 plus shipping.SE 6SN7 & 7591S amplifier
- By Jeanper
- Tubes / Valves
- 29 Replies
I am building a valve amplifier, single ended, no feedback, triode-connected 7591S amplifier. For driver valve I am using one 6SN7. The schematic I am planning to use is based on Mikael Abdellah's KT88 amplifier and looks like this:
But I am unsure about the values on most components.
The things that are fixed: the tubes, output transformer and B+. Everything else is subject to change.
Thoughts? Tips? 🙂
But I am unsure about the values on most components.
The things that are fixed: the tubes, output transformer and B+. Everything else is subject to change.
Thoughts? Tips? 🙂
Calamity - 30 Watt with Precision
- By lineup
- Solid State
- 29 Replies
Calamity amplifier
features
features
- Power Supply 2x20VAC transformer ~ +/-27VDC
- Bootstrapped VAS stage
- Transitional Miller Compensation, TMC
- Output more than 30 Watt into 8 Ohm
- Precision = THD 0.00004% at 1 Watt
AI-Assisted DJ Monitor Design Concept: First Build. Seeking Some Guidance from the Experts
Hey everyone,
I'm new to the forum but have been diving quite deep into speaker design resources, including this awesome community! I've been soaking up knowledge from your posts, YouTube tutorials and to kickstart my first build, I've been experimenting with some AI help to develop a concept. I'm eager to get your expert feedback—always good to have a human reality check on those AI ideas! 🙂 This will be my first proper speaker project, though I did build some basic car speaker based boxes with my dad when I was a kid.
My Goal: A versatile DJ monitor system that can handle both home listening and small house parties with powerful bass, clear highs, and the flexibility to switch between sitting and standing listening heights.
Main Challenges:
I'd love to hear your thoughts on this concept. All insights are welcome!
Here are some first simple sketches of the system:
Seated
Standing
12" - Subwoofer model VituixCAD
8" - Closed top model VituixCAD
Inspiration
I'm new to the forum but have been diving quite deep into speaker design resources, including this awesome community! I've been soaking up knowledge from your posts, YouTube tutorials and to kickstart my first build, I've been experimenting with some AI help to develop a concept. I'm eager to get your expert feedback—always good to have a human reality check on those AI ideas! 🙂 This will be my first proper speaker project, though I did build some basic car speaker based boxes with my dad when I was a kid.
My Goal: A versatile DJ monitor system that can handle both home listening and small house parties with powerful bass, clear highs, and the flexibility to switch between sitting and standing listening heights.
Main Challenges:
- Balancing relatively compact size with the ability to deliver impactful low-end for electronic music genres.
- Being able to cover a wide listening area and fill a room of around 25m2 with sound.
- Have a modular system where the top's can reach low enough to be used on their own.
- System: 2 x 2-way closed top boxes + 2 x ported subwoofers
- Amplification: Hypex FusionAmp FA253 with built-in DSP (easy plug & play DJ mixer)
- DSP Presets: Flat, Warm (for tops only), and Subwoofer Integrated
- Target Tuning Frequency: 45Hz (tops only), 25-30Hz (with subs)
- Sound Signature: Primarily flat, with a warm DSP option for versatility
- Aesthetics: Inspired by the clean and modern designs of Newfidelity J.J 8.1 and Ojas speakers. (see inspiration below)
- Subwoofer: Scan-Speak Discovery 30W/4558T00 (12") - Data sheet
- Mid/Bass: Scan-Speak Discovery 22W-4534G00 (8") - Data sheet
- Tweeter: Faital Pro HF108R (1") - Data sheet
- Waveguide: Eighteen Sound XT1086 - Data sheet
- Amplifier: Hypex FA253 - Specifications
- Subwoofer to Tops (80-100 Hz)
- Mid/Bass to Tweeter (2-3 kHz)
- PA Systems: Too bulky, aesthetically unappealing for home use, and often lacking in high-fidelity sound quality.
- Studio Monitors: While sonically impressive, they typically lack the loudness, bass extension, and wide dispersion needed for the intended use.
- Direct stacking on the subs for seated listening. (Probably will use them in this position most of the time)
- Distance rods for standing DJ monitor height.
- Wall/ceiling mounting as a potential future option.
- Does the driver selection seem well-suited to the goals?
- Will this amplifier work well for this idea? (Is matching 4 ohm and 8 ohm drivers a problem?)
- I've used subtle low shelf filters in the VituixCAD models to extend the low frequency range a bit. Is this similar to what is possible within the Hypex Filter Design software?
- Any concerns about the waveguide choice? (if so, what would be better options?)
- Any other suggestions or alternative components worth exploring?
- Check your feedback 🙂
- Detailed design of cabinets in Sketch Up
- Learn more about the Hypex Filter Design software
- Build cabinets
I'd love to hear your thoughts on this concept. All insights are welcome!
Here are some first simple sketches of the system:
Seated
Standing
12" - Subwoofer model VituixCAD
8" - Closed top model VituixCAD
Inspiration
Beresford TC-7533 Hi-Fi DAC & Headphone Amplifier
Excellent condition.
Specs:
Price: 150 euro
========
Will be shipped securely.
Location: Sofia, Bulgaria
Contact me here or by email: veselin.karavelov@gmail.com
Specs:
- 4 Digital Inputs (S/P-DIF - 2 optical, 2 coaxial)
- 1 Analogue Outputs (Cinch - fixed)
- Headphone Amplifier (6,3-mm-Jack) with Volume Control: 12 to 600 Ohm, 700mW
- Frequency Response: 20 Hz to 20 kHz
- Signal-to-Noise Ratio: > 103 dB
- Channel Separation: > 100 dB @ 1 kHz
- Total Harmonic Distortion: < 0,0015 % @ 1kHz
- Resolution: up to 24 bit
- Sample Rate: 28 to 192 kHz
- Burr-Brown Converters
- LED Indicator for chosen Input
- Colour LED for On-/Off-Switch
- Direct Current Sink: Device can be used worldwide
- Gold-plated Connectors
- Solid, Black Metal Case
- CE certified
- Valuable Switching Power Supply (12 Volts DC) included
- Dimensions: 180 mm × 140 mm × 50 mm
Price: 150 euro
========
Will be shipped securely.
Location: Sofia, Bulgaria
Contact me here or by email: veselin.karavelov@gmail.com
SUN Valley P1616D Power AMP
SV-P1616D/VK Pentode Power-amplifier
Hashimoto version HW-40-5 kit 120V/240V
NO Volume Pot
Point to point assembly
Kit or assembled version available in Early December
The production version will get rid of the volume port
The frequency reponse with HW-40-5
I accept preorder
Hashimoto version HW-40-5 kit 120V/240V
NO Volume Pot
Point to point assembly
Kit or assembled version available in Early December
The production version will get rid of the volume port
The frequency reponse with HW-40-5
I accept preorder
A simple and easy Dielectric-Absorption evaluator, the D.A.-Boy
- By Elvee
- Equipment & Tools
- 55 Replies
Hi there,
Here is another cheap & cheerful (and useful!) project: a dielectric absorption test-set.
What is DA (dielectric absorption)?
In a nutshell, DA is a parasitic effect affecting dielectric materials, and the capacitors they are made of.
Any real capacitor can be modelled as an infinite series of RC circuits.
In "good" capacitors, the first RC's total a large capacitance, and similar series resistances, resulting in an ideal cap in series with the ESR being the // sum of elementary R's.
Higher order effects are essentially minimal, and all of the losses are concentrated in the ESR, or the Q, the tan delta, the parallel damping resistance, .... etc: all these parameters are perfectly equivalent, and can be mathematically converted into any other one.
DA is somewhat different: although it counts as losses as it is a dissipative process, its real impact is absolutely minimal.
For example, mica is infamously known as one of the worst dielectric regarding DA, yet its losses remain very low.
This is the reason why this particular loss process has received a special treatment.
Although the energetic impact is minimal, the effect on the signals is far from negligible.
In dielectrics affected by DA, the elementary RC's of the series decrease more slowly, meaning a significant part of the total capacitance is hidden behind large R's, and large RC time-constants.
In practice, this means that when you attempt to charge or discharge such a cap very quickly, the farthest caps remain unaffected, and change the voltage and current after the event.
This delayed response leads to a host of unwanted effects, sometimes difficult to identify or attribute.
Some examples: the LF capacitance is larger than the HF one, sample-hold circuits show a small drop just after the sampling pulse, ramp generators have non-linearities, characterized by an excessive rise after the reset pulse, higher amplitude up to 50%, and lower amplitude afterwards.
It causes inaccuracies in the response of filters and equalization networks.
If you had the misguided idea of building a high-accuracy RIAA network from precision mica capacitors, the LF response would deviate from the ideal, even if you use 0.25% caps and 0.05% resistors.
In pulse circuits, it increases the settling time, in video signals, it causes streaking and lagging effects, and disrupts the black level, etc.
What causes DA?
The base dielectric material plays a major role, obviously, but many other factors also have an effect.
The presence of heterogeneities in the dielectric is an important one.
They can be discrete, like multi-sheet or multi-dielectrics caps, macroscopic as in layered materials like mica or granular materials like ceramics, or microscopic at the molecular level.
The presence of bubbles, voids, impurities, inclusions, wrinkles, fractures or other imperfections in the dielectric greatly increases the DA.
This means that composites, like PCB materials generally have a large DA.
The construction of the capacitor is extremely important: PP or PS are excellent dielectrics in theory, but a poor construction can totally ruin a capacitor based on these dielectrics.
Capacitors from the same production batch, in perfect condition, can display significant DA characteristics differences, even when all the rest is nominal.
DA is not systematically tested, but it is a good indicator of the quality and consistency of the production, as it is very sensitive to to the slightest contamination or deviation.
How is DA measured?
The universal method is to charge the CUT to a known voltage, keep it charged for a soaking time, discharge it briefly, let it recover completely disconnected, and finally measure the recovered voltage.
The ratio of the recovered voltage to the initial voltage is the DA value.
In this process, absolutely everything counts and influences the end result.
The only way to reproduce a result is to use strictly identical conditions.
Most accepted methods use time-scales of minutes or tens of minutes, and use mercury-wetted relays and similar devices.
Not very convenient for a fast, casual use.
The evaluator I propose does things more simply, but more importantly, it does so at a (comparatively) blindingly fast speed: the total cycle time is 1 second, and although the reading needs a little longer to settle, it is still tens of times faster than any "official" alternative.
What is the value of such an accelerated measurement?
Basically, it indicates DA when it is present and the parameters of the circuit have been tweaked to mimic "standard" results (remembering that there are in fact no such standards, it just follows the mainstream trend).
If you build the tester, you will have your own, stable reference, and if you test a number of known samples, you will get a feeling of what a good DA is.
If other DIYers build the same instrument, you will be able to compare your results with others.
The circuit is simple and cheap, based mostly on commodities except for the opamp, which is not especially rare or expensive and can easily be substituted.
I propose two versions: one is adjustment-free and has no bells and whistles like a low-batt. indicator, the other has compensations and adjustments to improve the absolute accuracy.
The evaluator will work from 1nF to 10µF without needing to switch anything, and has two ranges: 1% full range, and 10% full range.
It is designed as a multimeter add-on, and plugs into the standard 3/4' spaced input ports of most digital multimeters: mains plugs and outlets use the same standard, meaning the tester is housed in the shell of an AC/DC wallwart.
The "luxury" version includes a small galvanometer, allowing a stand-alone operation.
The sensitivity is sufficient to distinguish between two slightly different flavors of PP caps.
The 10% range is sufficient for reasonably good caps: PP, PS, PET, PC, ceramic COG or X7R.
It is insufficient for high-k ceramics, Ecaps, bad paper caps, but you don't need a tester to be aware of that.
If you really need to know the details, you can add a range having a lower gain.
This is the "light" version:
And this is the full one:
This is how my build looks:
A look inside:
Here is another cheap & cheerful (and useful!) project: a dielectric absorption test-set.
What is DA (dielectric absorption)?
In a nutshell, DA is a parasitic effect affecting dielectric materials, and the capacitors they are made of.
Any real capacitor can be modelled as an infinite series of RC circuits.
In "good" capacitors, the first RC's total a large capacitance, and similar series resistances, resulting in an ideal cap in series with the ESR being the // sum of elementary R's.
Higher order effects are essentially minimal, and all of the losses are concentrated in the ESR, or the Q, the tan delta, the parallel damping resistance, .... etc: all these parameters are perfectly equivalent, and can be mathematically converted into any other one.
DA is somewhat different: although it counts as losses as it is a dissipative process, its real impact is absolutely minimal.
For example, mica is infamously known as one of the worst dielectric regarding DA, yet its losses remain very low.
This is the reason why this particular loss process has received a special treatment.
Although the energetic impact is minimal, the effect on the signals is far from negligible.
In dielectrics affected by DA, the elementary RC's of the series decrease more slowly, meaning a significant part of the total capacitance is hidden behind large R's, and large RC time-constants.
In practice, this means that when you attempt to charge or discharge such a cap very quickly, the farthest caps remain unaffected, and change the voltage and current after the event.
This delayed response leads to a host of unwanted effects, sometimes difficult to identify or attribute.
Some examples: the LF capacitance is larger than the HF one, sample-hold circuits show a small drop just after the sampling pulse, ramp generators have non-linearities, characterized by an excessive rise after the reset pulse, higher amplitude up to 50%, and lower amplitude afterwards.
It causes inaccuracies in the response of filters and equalization networks.
If you had the misguided idea of building a high-accuracy RIAA network from precision mica capacitors, the LF response would deviate from the ideal, even if you use 0.25% caps and 0.05% resistors.
In pulse circuits, it increases the settling time, in video signals, it causes streaking and lagging effects, and disrupts the black level, etc.
What causes DA?
The base dielectric material plays a major role, obviously, but many other factors also have an effect.
The presence of heterogeneities in the dielectric is an important one.
They can be discrete, like multi-sheet or multi-dielectrics caps, macroscopic as in layered materials like mica or granular materials like ceramics, or microscopic at the molecular level.
The presence of bubbles, voids, impurities, inclusions, wrinkles, fractures or other imperfections in the dielectric greatly increases the DA.
This means that composites, like PCB materials generally have a large DA.
The construction of the capacitor is extremely important: PP or PS are excellent dielectrics in theory, but a poor construction can totally ruin a capacitor based on these dielectrics.
Capacitors from the same production batch, in perfect condition, can display significant DA characteristics differences, even when all the rest is nominal.
DA is not systematically tested, but it is a good indicator of the quality and consistency of the production, as it is very sensitive to to the slightest contamination or deviation.
How is DA measured?
The universal method is to charge the CUT to a known voltage, keep it charged for a soaking time, discharge it briefly, let it recover completely disconnected, and finally measure the recovered voltage.
The ratio of the recovered voltage to the initial voltage is the DA value.
In this process, absolutely everything counts and influences the end result.
The only way to reproduce a result is to use strictly identical conditions.
Most accepted methods use time-scales of minutes or tens of minutes, and use mercury-wetted relays and similar devices.
Not very convenient for a fast, casual use.
The evaluator I propose does things more simply, but more importantly, it does so at a (comparatively) blindingly fast speed: the total cycle time is 1 second, and although the reading needs a little longer to settle, it is still tens of times faster than any "official" alternative.
What is the value of such an accelerated measurement?
Basically, it indicates DA when it is present and the parameters of the circuit have been tweaked to mimic "standard" results (remembering that there are in fact no such standards, it just follows the mainstream trend).
If you build the tester, you will have your own, stable reference, and if you test a number of known samples, you will get a feeling of what a good DA is.
If other DIYers build the same instrument, you will be able to compare your results with others.
The circuit is simple and cheap, based mostly on commodities except for the opamp, which is not especially rare or expensive and can easily be substituted.
I propose two versions: one is adjustment-free and has no bells and whistles like a low-batt. indicator, the other has compensations and adjustments to improve the absolute accuracy.
The evaluator will work from 1nF to 10µF without needing to switch anything, and has two ranges: 1% full range, and 10% full range.
It is designed as a multimeter add-on, and plugs into the standard 3/4' spaced input ports of most digital multimeters: mains plugs and outlets use the same standard, meaning the tester is housed in the shell of an AC/DC wallwart.
The "luxury" version includes a small galvanometer, allowing a stand-alone operation.
The sensitivity is sufficient to distinguish between two slightly different flavors of PP caps.
The 10% range is sufficient for reasonably good caps: PP, PS, PET, PC, ceramic COG or X7R.
It is insufficient for high-k ceramics, Ecaps, bad paper caps, but you don't need a tester to be aware of that.
If you really need to know the details, you can add a range having a lower gain.
This is the "light" version:
And this is the full one:
This is how my build looks:
A look inside:
Attachments
DBX 2231 EQ - Equalizer Op Amp Rolling
- By Ted_B
- Analog Line Level
- 12 Replies
I have a dbx 2231 EQ that I use to tune a home HiFi system to a Harman curve at my listening position using REW. I bought this having seen the results of testing and a favorable review by ASR, and I’ve found that I presently prefer this to the DSP route that I used previously. Powered by a filtered conditioner and using balanced connections, this EQ is dead quiet in this system and I have noted no perceptible degradation in signal integrity, separation, or soundstage.
That being said, having observed audible improvements made by various discrete class A op amps (e.g. Sparkos, Burson, etc.) in the output stages of DACs, that makes me curious if op amp rolling may have an effect in this EQ. The architecture employs (4) NE 5532s on the input and output stages, and (32) NJM 4560s in the constant Q bandpass filters. One might speculate as to why these particular op amps were used, certainly cost was a factor, and I’m surprised the filters aren’t the 4560DD low noise versions although no noise is apparent, not audible noise anyway.
Having both newer Sparkos and Burson discrete op amps on hand, I felt this may make for an interesting exercise. I asked Andrew Sparks for his opinion, and he suggested trying the output and input parts first. Swapping the four NE5532s on the inputs and outputs involves just a bit of effort on my part to remove the four solder-through NE5532 ICs and replace with DIP8 sockets that I have on hand. On the other hand, swapping all those filter op amps for discretes would be prohibitively expensive even if the PS were up to it, and I'm not as optimistic that newer IC op amps would justify the hassle of swapping all those NJM 4560s, even for experimental purposes, although I found one person who did this about 10 years ago.
Any thoughts, intuition, hallucinations, etc., on this subject are appreciated.
That being said, having observed audible improvements made by various discrete class A op amps (e.g. Sparkos, Burson, etc.) in the output stages of DACs, that makes me curious if op amp rolling may have an effect in this EQ. The architecture employs (4) NE 5532s on the input and output stages, and (32) NJM 4560s in the constant Q bandpass filters. One might speculate as to why these particular op amps were used, certainly cost was a factor, and I’m surprised the filters aren’t the 4560DD low noise versions although no noise is apparent, not audible noise anyway.
Having both newer Sparkos and Burson discrete op amps on hand, I felt this may make for an interesting exercise. I asked Andrew Sparks for his opinion, and he suggested trying the output and input parts first. Swapping the four NE5532s on the inputs and outputs involves just a bit of effort on my part to remove the four solder-through NE5532 ICs and replace with DIP8 sockets that I have on hand. On the other hand, swapping all those filter op amps for discretes would be prohibitively expensive even if the PS were up to it, and I'm not as optimistic that newer IC op amps would justify the hassle of swapping all those NJM 4560s, even for experimental purposes, although I found one person who did this about 10 years ago.
Any thoughts, intuition, hallucinations, etc., on this subject are appreciated.
For Sale Unused Hammond transformers and inductors in their original boxes
I am selling unused Hammond transformers and inductors in their original boxes.
273BX $80 1 available
272DX $70 each, 2 available
159P $22 each, 2 available
159ZL $25 each, 4 available
Specifications are available at the manufacturer’s web site.
Transformers
Inductors
Due to weight, I don’t think it would make sense to ship any item outside the USA. USPS Priority Mail makes shipping within the USA reasonable. Based on their boxes’ dimensions the items require a medium flat rate box, currently $18.40.
USPS domestic flat rates
Payment through Zelle.
273BX $80 1 available
272DX $70 each, 2 available
159P $22 each, 2 available
159ZL $25 each, 4 available
Specifications are available at the manufacturer’s web site.
Transformers
Inductors
Due to weight, I don’t think it would make sense to ship any item outside the USA. USPS Priority Mail makes shipping within the USA reasonable. Based on their boxes’ dimensions the items require a medium flat rate box, currently $18.40.
USPS domestic flat rates
Payment through Zelle.
Restoring an awful DIY speaker
- Multi-Way
- 45 Replies
Hello everybody, I am a long time lurker and a first time poster (more like second, but nevermind...)
Back in 2019 I built a pair of two ways, with Dayton DSA135 and DC28 drivers and an 8’’ passive radiator. I thought I could get away with a pre-assembled xover (as many beginners do), and I throw one in. The resulting sound was anticlimactic to say the least…
These boxes have been sitting in my bedroom mainly for playing white noise throughout the night, and ocassionally some music (with little to no joy). Recently, I have decided to use them in the living room in a 2.1 configuration, and possibly as my fronts in a 5.1 setup in the near future. So, I thought I’d better take some measurements and see what’s really wrong with them, and boy, was I horrified…(viewer discretion advised)
tweeter alone:
Apart from the very low quality, pre-assembled xover (which is not worth talking about), the main problem appeared to be the recess I made for the tweeters. My brilliant thinking was ‘let’s align these little guys with the woofers’ but I had no idea that it was gonna cause all kinds of phase issues, as they are clearly evident with these dramatic nulls.
Instead of building new cabinets, I felt I'd much rather save these ones, but something clearly had to be done about those cavities. I figured if I can fit a waveguide in there, the problem would be solved. So I ordered a couple of Visaton wg148’s and while I am at it, I purchased a pair of SB15nrx’s, because why not? I also had a pair of Morel MDT29 tweeters from another half baked project, and I decided to use them with the waveguides. Again, why not? After a nerve racking operation, with virtually zero margin for error, I was able to fit both drivers.
And here are the new measurements (red being the tweeter and orange the woofer)
I have been fiddling with some xover designs in Xsim and I am slowly getting there, but that baffle loss I am getting around 600hz is giving me headaches. The baffle is quite narrow at around 165mm (6.5 inches) and as you can see in the graph, between 1.1k and 500hz, almost 10db is lost. Is this normal behavior or should I be worried? If I am to flatten it out, I am guessing the sensitivity of the speaker is gonna suffer a lot, am I right? (Mind you the cabinet is not properly sealed right now, there are some air leakages here and there because of all the cables and what not. But I am assuming it shouldn’t be a problem at these frequencies.)
I will be updating my progress along the way but as a beginner, I'd love to hear what you people have to say about this project and the baffle loss particularly.
Many thanks, peace.
Back in 2019 I built a pair of two ways, with Dayton DSA135 and DC28 drivers and an 8’’ passive radiator. I thought I could get away with a pre-assembled xover (as many beginners do), and I throw one in. The resulting sound was anticlimactic to say the least…
These boxes have been sitting in my bedroom mainly for playing white noise throughout the night, and ocassionally some music (with little to no joy). Recently, I have decided to use them in the living room in a 2.1 configuration, and possibly as my fronts in a 5.1 setup in the near future. So, I thought I’d better take some measurements and see what’s really wrong with them, and boy, was I horrified…(viewer discretion advised)
tweeter alone:
Apart from the very low quality, pre-assembled xover (which is not worth talking about), the main problem appeared to be the recess I made for the tweeters. My brilliant thinking was ‘let’s align these little guys with the woofers’ but I had no idea that it was gonna cause all kinds of phase issues, as they are clearly evident with these dramatic nulls.
Instead of building new cabinets, I felt I'd much rather save these ones, but something clearly had to be done about those cavities. I figured if I can fit a waveguide in there, the problem would be solved. So I ordered a couple of Visaton wg148’s and while I am at it, I purchased a pair of SB15nrx’s, because why not? I also had a pair of Morel MDT29 tweeters from another half baked project, and I decided to use them with the waveguides. Again, why not? After a nerve racking operation, with virtually zero margin for error, I was able to fit both drivers.
And here are the new measurements (red being the tweeter and orange the woofer)
I have been fiddling with some xover designs in Xsim and I am slowly getting there, but that baffle loss I am getting around 600hz is giving me headaches. The baffle is quite narrow at around 165mm (6.5 inches) and as you can see in the graph, between 1.1k and 500hz, almost 10db is lost. Is this normal behavior or should I be worried? If I am to flatten it out, I am guessing the sensitivity of the speaker is gonna suffer a lot, am I right? (Mind you the cabinet is not properly sealed right now, there are some air leakages here and there because of all the cables and what not. But I am assuming it shouldn’t be a problem at these frequencies.)
I will be updating my progress along the way but as a beginner, I'd love to hear what you people have to say about this project and the baffle loss particularly.
Many thanks, peace.
Attachments
For Sale TANNOY I8 - 8" Dual Concentric Speakers with the 2062 Coaxial Drivers
Attachments
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For Sale Verum 1 MKII Headphones Zebrano Brown + silver
- By pinnocchio
- Swap Meet
- 13 Replies
Attachments
For Sale UK - Neurochrome 686 - all boards - fully assembled and working
Neurochrome 686 fully assembled
All working as it should, no power on/off thumps just the quiet clicks from the relays
Case Dimensions in mm (approx)
450 wide v 410 deep x 190 high
Note: the sockets and switch add depth so allowing for cables etc front to rear depth in use is about 490mm
The Amplifier Includes:
2 x Neurochrome Modulus 686 boards
2 x Neurochrome Power supply boards – one for each channel, 88000uf per channel
1 x Neurochrome Intelligent Soft Start
2 x Neurochrome Guardian speaker protection – one for each channel
Green Ground/Earth Socket on rear
XLR inputs
4mm Speaker terminals
1 x Mains Transformer 800 watt with separate windings for each channel.
£2000 firm
All working as it should, no power on/off thumps just the quiet clicks from the relays
Case Dimensions in mm (approx)
450 wide v 410 deep x 190 high
Note: the sockets and switch add depth so allowing for cables etc front to rear depth in use is about 490mm
The Amplifier Includes:
2 x Neurochrome Modulus 686 boards
2 x Neurochrome Power supply boards – one for each channel, 88000uf per channel
1 x Neurochrome Intelligent Soft Start
2 x Neurochrome Guardian speaker protection – one for each channel
Green Ground/Earth Socket on rear
XLR inputs
4mm Speaker terminals
1 x Mains Transformer 800 watt with separate windings for each channel.
- 2 x 400 watts windings @ 25vac
- One winding for each channel
£2000 firm
Attachments
For Sale London UK: 2A3 SE amplifier, premium parts
- By andyjevans
- Swap Meet
- 12 Replies
For sale - my 2a3 SE amplifier with state of the art power supply - big Hammond transformer and choke, GZ34 rectifier, Black Gate bypass caps on the 2a3.
Input section is a 6N1P with teflon coupling caps, Kemet DC Link bypasses and Holco resistors. All premium parts.
Configured right now as just an amplifier but I can add a selector and volume control as needed to make it integrated.
Asking£485 excluding 2a3 valves. REDUCED to £460 including nearly new Sovtek 2a3s.
Situated Kensington, London. Auditions welcome. PM me with any questions.
Input section is a 6N1P with teflon coupling caps, Kemet DC Link bypasses and Holco resistors. All premium parts.
Configured right now as just an amplifier but I can add a selector and volume control as needed to make it integrated.
Asking
Situated Kensington, London. Auditions welcome. PM me with any questions.
JBL 2360 horn - Shape of entry
Hi all,
I have two JBL 2360 horns, and in the (near) future I want to purchase 2 CD's for them. What strikes me is the shape of the 2" horn entry, see the image below. It is certainly not circular (top to bottom: ~51mm, left to right ~47mm). Both of them look the same. Seeing this got me thinking: is it worth to invest in 600 euro drivers like the BMS or B&C coaxials for this horn? It feels a bit like using a highly advanced tight toleranced driver attached to a horn of the 'olden day's'. (Don't know what I get myself into by saying this) 🙂
Hopefully some of you can share their experience with this horn and/or give some insight of the effect of coupling a perfect circular 2" CD to this horn entry.
Thanks!
I have two JBL 2360 horns, and in the (near) future I want to purchase 2 CD's for them. What strikes me is the shape of the 2" horn entry, see the image below. It is certainly not circular (top to bottom: ~51mm, left to right ~47mm). Both of them look the same. Seeing this got me thinking: is it worth to invest in 600 euro drivers like the BMS or B&C coaxials for this horn? It feels a bit like using a highly advanced tight toleranced driver attached to a horn of the 'olden day's'. (Don't know what I get myself into by saying this) 🙂
Hopefully some of you can share their experience with this horn and/or give some insight of the effect of coupling a perfect circular 2" CD to this horn entry.
Thanks!
Vintage NAD 3020 amplifier history and simulation in LTSpice with possible simple improvements
- By pbilous
- Solid State
- 10 Replies
NAD 3020
The NAD 3020 amplifier, introduced in 1978 by New Acoustic Dimension (NAD), is a landmark in hi-fi audio history. Designed by Bjørn Erik Edvardsen, the NAD 3020 was a game-changer, challenging the notion that high-quality sound required a significant financial investment. At the time, the audio market was dominated by expensive, high-powered amplifiers. The NAD 3020, with its modest price and minimalist design, revolutionized the landscape by offering exceptional sound quality to a broader audience.
The NAD 3020 quickly gained a reputation for its remarkable performance. Despite its modest power rating of 20 watts per channel, it delivered much higher dynamic headroom, allowing it to handle musical peaks with impressive clarity and power. This capability enabled the amplifier to compete with higher-powered models, providing an audio experience that defied its wattage. Another key feature was its high current capability, crucial for driving difficult speaker loads and controlling speaker cones with precision. This resulted in detailed and accurate sound reproduction, making the NAD 3020 suitable for a wide range of speakers and musical genres.
A significant draw for vinyl enthusiasts was the integrated high-quality phono stage, which allowed turntables to be connected directly to the amplifier, offering a warm and rich analog sound without the need for an external phono preamp. The design simplicity of the NAD 3020, both externally and internally, contributed to its superior performance. By keeping the signal path clean and using high-quality components where it mattered most, NAD ensured the amplifier could deliver pure and uncolored sound, enhancing its reliability and longevity.
The most celebrated aspect of the NAD 3020's sound was its musicality and warmth. Renowned for its ability to reproduce music with a sense of rhythm and timing, it made listening enjoyable and engaging. Its warm sound signature added richness to the audio, making it a favorite among audiophiles and casual listeners alike. The NAD 3020 remains an iconic piece of audio equipment, revered for its groundbreaking approach to sound quality and affordability. Its unique blend of power, high current capability, and musical warmth set it apart from other amplifiers of its time, contributing to its legendary status. Decades after its introduction, the NAD 3020 continues to inspire and influence modern amplifier design, cementing its place in the annals of hi-fi history.
NAD 2150
The NAD 2150 amplifier, introduced in the early 1980s, is part of NAD's legacy of producing high-quality, affordable audio equipment. It employs the same foundational design concepts that made the NAD 3020 a legend in the audio world. Both amplifiers feature a singleton input stage with a constant current source, which ensures stable and low-noise operation. Next stage - VAS (voltage amplification stage) is using complimentary feedback transistor pair, which enhances linearity and reduces distortion, allowing for a more accurate and musical sound reproduction. And finally, both models utilize an emitter follower class AB output stage, providing a balanced mix of efficiency and sound quality.
However, a significant enhancement in the NAD 2150 is its use of higher current capability output transistors. These transistors enable the 2150 to drive more demanding speaker loads with greater control and robustness, resulting in improved performance, especially with contemporary, power-hungry speakers.
Another notable difference between the NAD 2150 and its predecessor is the absence of the preamp section in the 2150. While the NAD 3020 included a preamp, making it a versatile all-in-one solution, the 2150's omission of this section makes it particularly well-suited for modern audio setups. This design choice allows users to feed the signal directly from modern DACs and other high-quality sources without the additional signal path introduced by an integrated preamp. As a result, the NAD 2150 can offer a purer and more direct signal, aligning perfectly with the preferences of today's audiophiles who often favor streamlined, minimalistic systems for the highest fidelity audio reproduction.
Singelton input stage
The singleton input stage, as utilized in amplifiers like the NAD 3020, offers distinct advantages that contribute to its enduring appeal in audio design. Unlike the differential pair, which typically involves two transistors, the singleton input stage simplifies the circuitry. This simplicity often results in lower overall noise and distortion levels, crucial for preserving the fidelity of audio signals. Additionally, the singleton configuration can offer better phase accuracy and transient response, allowing for a more accurate portrayal of the original audio waveform. These characteristics make the singleton input stage particularly well-suited for applications where high-fidelity reproduction and transparency are paramount.
However, it's essential to acknowledge that the singleton input stage has drawbacks compared to the differential pair. One notable limitation is its typically lower common-mode rejection ratio (CMRR) compared to differential configurations. This means it may be more susceptible to common-mode noise and interference, potentially impacting signal quality in environments with electrical noise. Additionally, the thermal stability and matching characteristics of the singleton input stage may not be as robust as those of differential pairs, which can affect performance consistency over varying operating conditions.
Despite these considerations, the NAD 3020 amplifier's historical success and revered sound quality stand as testament to the effectiveness of the singleton input stage when implemented with careful design considerations. The 3020's ability to deliver clean, natural sound with minimal coloration has solidified its place in audio history and continues to influence modern amplifier designs. Its enduring popularity underscores the viability and effectiveness of the singleton input stage in achieving high-quality audio reproduction, showcasing its strengths in the context of critical listening environments and audiophile preferences.
My story
After immersing myself in the rich history and technical details of vintage hi-fi equipment, particularly the NAD 3020 and its successor, the NAD 2150, I decided to delve deeper into this world by acquiring a NAD 2150 amplifier.
Intrigued by its renowned design principles I sought to explore its inner workings further. I obtained the service manual, complete with schematics, and delved into understanding how these components interact to produce the amplifier's distinctive sound.
Driven by curiosity and a passion for electronics, I took my exploration a step further by simulating the NAD 2150's circuit layout using LTSpice, a circuit simulation software. This exercise not only deepened my understanding of amplifier design but also allowed me to visualize how different components contribute to its overall performance. Sketching the circuit in LTSpice was both educational and enjoyable, providing insights into the amplifier's behavior under various conditions.
For those brave enough to open the amp and solder a few capacitors a significant improvement can be made by swapping input filter capacitors to 22uF + 22uF and DC coupling capacitor to 4700uF resulting in 0.002% THD@1kHz.
The NAD 3020 amplifier, introduced in 1978 by New Acoustic Dimension (NAD), is a landmark in hi-fi audio history. Designed by Bjørn Erik Edvardsen, the NAD 3020 was a game-changer, challenging the notion that high-quality sound required a significant financial investment. At the time, the audio market was dominated by expensive, high-powered amplifiers. The NAD 3020, with its modest price and minimalist design, revolutionized the landscape by offering exceptional sound quality to a broader audience.
The NAD 3020 quickly gained a reputation for its remarkable performance. Despite its modest power rating of 20 watts per channel, it delivered much higher dynamic headroom, allowing it to handle musical peaks with impressive clarity and power. This capability enabled the amplifier to compete with higher-powered models, providing an audio experience that defied its wattage. Another key feature was its high current capability, crucial for driving difficult speaker loads and controlling speaker cones with precision. This resulted in detailed and accurate sound reproduction, making the NAD 3020 suitable for a wide range of speakers and musical genres.
A significant draw for vinyl enthusiasts was the integrated high-quality phono stage, which allowed turntables to be connected directly to the amplifier, offering a warm and rich analog sound without the need for an external phono preamp. The design simplicity of the NAD 3020, both externally and internally, contributed to its superior performance. By keeping the signal path clean and using high-quality components where it mattered most, NAD ensured the amplifier could deliver pure and uncolored sound, enhancing its reliability and longevity.
The most celebrated aspect of the NAD 3020's sound was its musicality and warmth. Renowned for its ability to reproduce music with a sense of rhythm and timing, it made listening enjoyable and engaging. Its warm sound signature added richness to the audio, making it a favorite among audiophiles and casual listeners alike. The NAD 3020 remains an iconic piece of audio equipment, revered for its groundbreaking approach to sound quality and affordability. Its unique blend of power, high current capability, and musical warmth set it apart from other amplifiers of its time, contributing to its legendary status. Decades after its introduction, the NAD 3020 continues to inspire and influence modern amplifier design, cementing its place in the annals of hi-fi history.
NAD 2150
The NAD 2150 amplifier, introduced in the early 1980s, is part of NAD's legacy of producing high-quality, affordable audio equipment. It employs the same foundational design concepts that made the NAD 3020 a legend in the audio world. Both amplifiers feature a singleton input stage with a constant current source, which ensures stable and low-noise operation. Next stage - VAS (voltage amplification stage) is using complimentary feedback transistor pair, which enhances linearity and reduces distortion, allowing for a more accurate and musical sound reproduction. And finally, both models utilize an emitter follower class AB output stage, providing a balanced mix of efficiency and sound quality.
However, a significant enhancement in the NAD 2150 is its use of higher current capability output transistors. These transistors enable the 2150 to drive more demanding speaker loads with greater control and robustness, resulting in improved performance, especially with contemporary, power-hungry speakers.
Another notable difference between the NAD 2150 and its predecessor is the absence of the preamp section in the 2150. While the NAD 3020 included a preamp, making it a versatile all-in-one solution, the 2150's omission of this section makes it particularly well-suited for modern audio setups. This design choice allows users to feed the signal directly from modern DACs and other high-quality sources without the additional signal path introduced by an integrated preamp. As a result, the NAD 2150 can offer a purer and more direct signal, aligning perfectly with the preferences of today's audiophiles who often favor streamlined, minimalistic systems for the highest fidelity audio reproduction.
Singelton input stage
The singleton input stage, as utilized in amplifiers like the NAD 3020, offers distinct advantages that contribute to its enduring appeal in audio design. Unlike the differential pair, which typically involves two transistors, the singleton input stage simplifies the circuitry. This simplicity often results in lower overall noise and distortion levels, crucial for preserving the fidelity of audio signals. Additionally, the singleton configuration can offer better phase accuracy and transient response, allowing for a more accurate portrayal of the original audio waveform. These characteristics make the singleton input stage particularly well-suited for applications where high-fidelity reproduction and transparency are paramount.
However, it's essential to acknowledge that the singleton input stage has drawbacks compared to the differential pair. One notable limitation is its typically lower common-mode rejection ratio (CMRR) compared to differential configurations. This means it may be more susceptible to common-mode noise and interference, potentially impacting signal quality in environments with electrical noise. Additionally, the thermal stability and matching characteristics of the singleton input stage may not be as robust as those of differential pairs, which can affect performance consistency over varying operating conditions.
Despite these considerations, the NAD 3020 amplifier's historical success and revered sound quality stand as testament to the effectiveness of the singleton input stage when implemented with careful design considerations. The 3020's ability to deliver clean, natural sound with minimal coloration has solidified its place in audio history and continues to influence modern amplifier designs. Its enduring popularity underscores the viability and effectiveness of the singleton input stage in achieving high-quality audio reproduction, showcasing its strengths in the context of critical listening environments and audiophile preferences.
My story
After immersing myself in the rich history and technical details of vintage hi-fi equipment, particularly the NAD 3020 and its successor, the NAD 2150, I decided to delve deeper into this world by acquiring a NAD 2150 amplifier.
Intrigued by its renowned design principles I sought to explore its inner workings further. I obtained the service manual, complete with schematics, and delved into understanding how these components interact to produce the amplifier's distinctive sound.
Driven by curiosity and a passion for electronics, I took my exploration a step further by simulating the NAD 2150's circuit layout using LTSpice, a circuit simulation software. This exercise not only deepened my understanding of amplifier design but also allowed me to visualize how different components contribute to its overall performance. Sketching the circuit in LTSpice was both educational and enjoyable, providing insights into the amplifier's behavior under various conditions.
For those brave enough to open the amp and solder a few capacitors a significant improvement can be made by swapping input filter capacitors to 22uF + 22uF and DC coupling capacitor to 4700uF resulting in 0.002% THD@1kHz.
Hello!
- By rzsantiago
- Introductions
- 2 Replies
Hello everyone!
I've always been passionate about music (just listening) and recently I began to be more interested in the equipment aspect to enjoy it more and better.
I started by making my own speakers, a version of the 'Overnight Sensations' by Paul Carmody. I tried them only with a class D amplifier and the first listening experience was incredible. From there I acquired an old Kendwood KA-300 amplifier in very good condition and again, the experience was better than the previous one and the loudness function helped a lot to better balance the sound of the speakers since I usually listen to them in a very small environment.
I'm really enjoying this journey of baby steps improvements😅 so I hope to continue improving my equipment and creating new ones.
Thanks for reading!
I've always been passionate about music (just listening) and recently I began to be more interested in the equipment aspect to enjoy it more and better.
I started by making my own speakers, a version of the 'Overnight Sensations' by Paul Carmody. I tried them only with a class D amplifier and the first listening experience was incredible. From there I acquired an old Kendwood KA-300 amplifier in very good condition and again, the experience was better than the previous one and the loudness function helped a lot to better balance the sound of the speakers since I usually listen to them in a very small environment.
I'm really enjoying this journey of baby steps improvements😅 so I hope to continue improving my equipment and creating new ones.
Thanks for reading!
2017 VFET kit - 2ea 2SK82/2SJ28 - SOLD
I'm selling the kit I purchased back in 2017 with matched VFETs and circuit board. I REALLY want to build the amp but I just don't see it happening any time soon and would like to pass it on to someone who will actually put them to good use. Purchased direct from diyaudiostore. Thanks for looking!
Edit: forgot the price: $250 including shipping. It was the 'essentials' kit that has the matched VFETS, PCB's and some screws
Edit: forgot the price: $250 including shipping. It was the 'essentials' kit that has the matched VFETS, PCB's and some screws
Magnetic cartridge preamp
- By Tube Radio
- Analogue Source
- 40 Replies
Is there a good quality small magnetic cartridge phono preamp board that can run on up to 12Vdc?
The B+ to the 45 player is +12Vdc as I needed to replace the stock motor with a DC brushless motor due to it inducing hum in the cartridge. I can use a LM-317 to derive any voltage under +12Vdc.
I've got an RCA 45 player I converted to a stereo magnetic cartridge and wanted a built in preamp so that I can plug it into any line level input.
The board needs to be relatively small as there's only a small place for it to fit.
Pictured is where the board has to go and also a previous attempt from a few years ago that didn't work so good. The existing board is 3" X 2 1/4", but there's enough space to where it can be 3" X 2 1/2".
The B+ to the 45 player is +12Vdc as I needed to replace the stock motor with a DC brushless motor due to it inducing hum in the cartridge. I can use a LM-317 to derive any voltage under +12Vdc.
I've got an RCA 45 player I converted to a stereo magnetic cartridge and wanted a built in preamp so that I can plug it into any line level input.
The board needs to be relatively small as there's only a small place for it to fit.
Pictured is where the board has to go and also a previous attempt from a few years ago that didn't work so good. The existing board is 3" X 2 1/4", but there's enough space to where it can be 3" X 2 1/2".
Mod/fix a vintage two way kit
About 30 years ago I've built a pair of bookshelf speakers based on Audax drivers. Recently, I got back to diyaudio during Covid. I felt It was dull so I bypass R1 but it is too hot. I've used it like that for few years, now the tweeter is dead on one channel.
The original Audax tweeter is hard to find now but there are similar design from local manufacturers with 4ohms impedance. I'm thinking of just put an attenuating resistor in series with new tweeter. Maybe a 2 ohm resistor so about -3.5dB at 6 ohm instead of -6dB at 8 ohms in original design.
Would that work? Do I need to think about phases?
NAD C 720BEE - worked great initially and then entered protected mode...solution included
- By Pernas
- Solid State
- 2 Replies
Hi!
Just wanted to share my experience from a few days ago when I found myself a rather nice (IMHO) looking NAD C 720BEE together with a C 525BEE CD player.
The amp was acquired as a replacement for the NAD 302 which I'm now a bit hesitant to leave running for longer periods due to it's lack of any protection circuit.
(More on that later).
The C 720BEE was cleaned and then tested without any issues whatsoever. However, a few days later when starting the 720BEE it remained in red (protected mode) regardless of speakers connected or not and I thought, bummer, time for a re-cap then.
(The SM only guided me to check the protection circuit to proceed though, not very helpful here).
However, before starting with the re-cap I really wanted to find the actual cause for this sudden regression - and soon found that the -18V supply was only at -1.16V when ON.
Ok, then tried to trace all possible caps involved in with the -18V supply without any success. Also, there was no obvious indication of abnormal current draw from the -37V either...
Strange I thought and then my wife suddenly appeared in the doorway and I quickly explained what I was doing and trying to find and then she out of the blue (she's very intuitive and smart) told me that I might be searching in the wrong place(s) and asked me about the circuit board and suggested that I should take a look at that instead:
...and she was right, the circuit board was to blame for this regression and the reason for the missing -18V was due to
that R414 didn't have any connection with the +18V side as the schematics below indicates:
The fix was a rather crude one with a link soldered to remedy the above and then it was back to the living!
(The soldering on this board didn't look too nice to start with, this unit could have been a lemon 😉)
Now I'm just awaiting new 2x15000uF caps for the power supply to arrive to finish the re-cap.
(Horrible that these 15000uF caps are live even when the AMP is in standby mode, it's really time since one of them has a small bulge...)
More to follow when AMP has been fixed up to specs!
Thanks for reading,
Per
Just wanted to share my experience from a few days ago when I found myself a rather nice (IMHO) looking NAD C 720BEE together with a C 525BEE CD player.
The amp was acquired as a replacement for the NAD 302 which I'm now a bit hesitant to leave running for longer periods due to it's lack of any protection circuit.
(More on that later).
The C 720BEE was cleaned and then tested without any issues whatsoever. However, a few days later when starting the 720BEE it remained in red (protected mode) regardless of speakers connected or not and I thought, bummer, time for a re-cap then.
(The SM only guided me to check the protection circuit to proceed though, not very helpful here).
However, before starting with the re-cap I really wanted to find the actual cause for this sudden regression - and soon found that the -18V supply was only at -1.16V when ON.
Ok, then tried to trace all possible caps involved in with the -18V supply without any success. Also, there was no obvious indication of abnormal current draw from the -37V either...
Strange I thought and then my wife suddenly appeared in the doorway and I quickly explained what I was doing and trying to find and then she out of the blue (she's very intuitive and smart) told me that I might be searching in the wrong place(s) and asked me about the circuit board and suggested that I should take a look at that instead:
...and she was right, the circuit board was to blame for this regression and the reason for the missing -18V was due to
that R414 didn't have any connection with the +18V side as the schematics below indicates:
The fix was a rather crude one with a link soldered to remedy the above and then it was back to the living!
(The soldering on this board didn't look too nice to start with, this unit could have been a lemon 😉)
Now I'm just awaiting new 2x15000uF caps for the power supply to arrive to finish the re-cap.
(Horrible that these 15000uF caps are live even when the AMP is in standby mode, it's really time since one of them has a small bulge...)
More to follow when AMP has been fixed up to specs!
Thanks for reading,
Per
-
Locked
Speaker recognition and how to remove the face from the mount, please.
- By jfmusic
- Introductions
- 4 Replies
Hi, I purchased a used set of 6422cfp, and they came with tweeters.
Anybody know what they are and how to separate the unit from the mount frame?
I have a heavy hand and am notorious for oops...
Thanks in advance
Anybody know what they are and how to separate the unit from the mount frame?
I have a heavy hand and am notorious for oops...
Thanks in advance
VTL IT-85 Schematic Needed
- By ampexperts
- Tubes / Valves
- 10 Replies
I'm in search of schematic for IT-85.
Peculiar problem between V101 and V102, intermittent loss of signal, V101 has a signal on pin 1, but it's not making it to V102. I see there are a couple of relays in there.
In addition, the other channel does not mute when the amplifier is warming up or after shutdown.
I've been over the solder joints that are accessible, but the next step is major disassembly to get that PCB out for inspection/repair.
A schematic would at least tell me what's in the signal path between those two tubes.
Problem suspected to be somewhere under the mass of wires and switch on the right hand side of this photo:
Peculiar problem between V101 and V102, intermittent loss of signal, V101 has a signal on pin 1, but it's not making it to V102. I see there are a couple of relays in there.
In addition, the other channel does not mute when the amplifier is warming up or after shutdown.
I've been over the solder joints that are accessible, but the next step is major disassembly to get that PCB out for inspection/repair.
A schematic would at least tell me what's in the signal path between those two tubes.
Problem suspected to be somewhere under the mass of wires and switch on the right hand side of this photo: