Using bi-amp in a 2.5way build to avoid a low impedance?
So, I am building a fun 2.5way tower speaker with 2 different bass drivers: the Wavecor WF152BD 4ohm 6" midbass, and a SBAcoustics SB17NBAC-8 or -4 for the lower woofer. The Wavecor will be the main driver in a sealed compartment, and the SB will be either in a separate sealed or maybe ported enclosure (TBD). The SB is really just there to fill in the bottom punch and offer the baffle step correction. Both woofers will be wired in-phase.
If I use a typical parallel crossover, I am looking at a pretty low impedance with two 4ohm drivers in parallel, so I would avoid that. I guess I will try the 8ohm woofer, but that still leaves me with a 3ohm dip right at 150hz. Below is the high-pass crossovers just for the two woofers. (Wavecor is in Green in the Tweeter section, SBA is in Blue in the Woofer section, sum in red. Tweeter is not profiled here, and yes I need to move to a better modeling tool, but I can use this one on my mobile while traveling for work):
I am just using standard FRD/ZMA files at first, to figure out the basics of my design and what components to order for the first try. Actual measurements will come later...
I was also considering creating a bi-amp setup, with one amp running the tweeter and Wavecor, and the second amp powering the SB driver. I think this makes it a bit safer? As each amp channel only sees one woofer.
My Marantz receiver can re-assign the surround amp outputs to be additional mains outs, giving 4 discrete mains channels: https://manuals.marantz.com/NR1608/EU/EN/DRDZSYcqhsmjdu.php
I was going to try that setup. But I have no idea what this statement in that link means: "This connection enables back EMF (power returned without being output) from the woofer to flow into the tweeter without affecting the sound quality, producing a higher sound quality."
I know what Back EMF is....I just don't understand it in this context... It seems backwards. I would think it should isolate BackEMF produced from the woofer motion in that channel, and not allow it to Flow Into the other channel.
If I use a typical parallel crossover, I am looking at a pretty low impedance with two 4ohm drivers in parallel, so I would avoid that. I guess I will try the 8ohm woofer, but that still leaves me with a 3ohm dip right at 150hz. Below is the high-pass crossovers just for the two woofers. (Wavecor is in Green in the Tweeter section, SBA is in Blue in the Woofer section, sum in red. Tweeter is not profiled here, and yes I need to move to a better modeling tool, but I can use this one on my mobile while traveling for work):
I am just using standard FRD/ZMA files at first, to figure out the basics of my design and what components to order for the first try. Actual measurements will come later...
I was also considering creating a bi-amp setup, with one amp running the tweeter and Wavecor, and the second amp powering the SB driver. I think this makes it a bit safer? As each amp channel only sees one woofer.
My Marantz receiver can re-assign the surround amp outputs to be additional mains outs, giving 4 discrete mains channels: https://manuals.marantz.com/NR1608/EU/EN/DRDZSYcqhsmjdu.php
I was going to try that setup. But I have no idea what this statement in that link means: "This connection enables back EMF (power returned without being output) from the woofer to flow into the tweeter without affecting the sound quality, producing a higher sound quality."
I know what Back EMF is....I just don't understand it in this context... It seems backwards. I would think it should isolate BackEMF produced from the woofer motion in that channel, and not allow it to Flow Into the other channel.
Reviving a Pioneer PD8500 no read
- Digital Source
- 7 Replies
A few months ago “surfing” into Marketplace looking for nothing, I saw a Cd player Pioneer PD8500 announced as “not working but well conserved. OPU must be changed. 20 bucks”. I think: high risk, low amount, ok let's go. The seller was right. The dead OPU had two defects. (1) Low power laser and (2) no movable lens. The mummy was the extinguished PWY-1011 pioneer pickup.
My first visual inspection was the laser power adjust trimmer, suspecting the easy way: full throttle for solve some past failure. And it was, minimum resistance regulation = high current = short laser life. First cause revealed.
The second seeking was for a locked lens or his armature. No news, all was ok. Then, I think, some driver burned, connector or power source out of spec. None of them. All were ok. Next step, resistance of focus and tracking lens coils. Voilá, the focus coils in open circuit, the tracking coils ok (8 ohm). Looking more deeply I found one of the copper tails from the base to the movable part broke, apparently . Second cause was revealed.
Starting with the last issue, I tried to re-weld the broken copper tail, but it was so short and in such a small space that I decided to drop off the 4 tails and replace them with longer wires. The donor was the cable of an apple earbud. After a surgery with magnifying glass, flux, tin soldering iron and patience, all the tails were left reconnected. Silicon glue was applied into welds as an effort dissipator. I had to be very very careful with the rubber suspension. In my opinion, the worst design ever made for lens stabilization (but I´m not a japanese engineer).
I follow. All reassembled, resistance checked (14 ohm focus, 8 ohm tracking), powered on and… the lens goes back to life!!, like a dog wagging its tail. But the laser intensity remained very low. I did not care.3
I put a CD, powered on again, and the focus detection shows began: the nudges for the spindle motor, the swing of lens, the seeking magic sound… but NO DISC fatal error. I did not care. News tests would begin. Laser current measure was 65mA, high, but no so much; power laser measure no possible (who have a pwr meter in this days?). Then a comparison with a healthy cd player, via cell camera, gave low power. Cleaned lens, lubed rails, re-adjusted tilt, but nothing. The fail was the same.
Then, the fact had to be faced: laser diode had to be passed to a better life, and replaced. Here, in a crossroad of change LD or try with other OPU, I took both: buy and replace the laser diode and develop an adaptation for other compatible OPU. The LDs selected were two: SLD105VL from Sony and RLD78MYR1 from Rohm. Why?, both 780nm, 5mW, AKA pinout and they were the best sellers on Aliexpress :|.
The OPU selected was the KSS313. Why?. Because this is cheap, with stock in Argentina and his dimensions appropriated to fit into the carriage, or was it what I expected.
The OPU came first, and surprise: the geometry dont fit any with the carriage… the second crossroads: sacrifice the original carriage or develop a new one, via 3D printing. The second was the election. After hours and hours of measuring, design, trial, re-adjust, the piece was builded.
Regarding the connections between the KSS313 and the board, a cross cable was necessary. The KSS´s flex connector was´nt compatible with the board. When all the parts were mounted and energized, the lens moved, and the LD goes shining. Welll done. A few tests revealed a high current in the KSS´s LD. Why??. Because the RF amplifier, a TA8137 Toshiba has different input sensitivity LD photodiode. Looking for a datasheet, they do not exist on the web (neither deep). Then I emailed Toshiba, and they responded to me (unbelievable!) that this IC wasn´t sold for a massive market and was a special development. Another Pioneer vaulted secret. Investigating other pioneer models, I could see that the issue was the VR for LD power adjustment. The KSS had a 2.2k and the required must be 4.7k. Changed and success!.
With the LD in his comfort zone, the RF signal remained absent. Aghhhh. And now what?. Looking again, I found that the KSS´s PDIC had some contact unsoldered. Surely my KSS OPU was a second hand or surplus. Once corrected this, the RF signal, or some similar, appeared at test point TP1. Yes!!. But not so good. A lot of electrical noise was present as an RF signal. New solutions were applied, shielding, cable re-routing, testing and testing, all resulted unsatisfactory, and discouraging. With a sledge hammer to destroy all in mind, the purchased LDs arrived from China, 4 months after. This is Argentina's style.
The last chance would be the change of LD. The main difference between Sony and Rohm is the focal point. An essential spec for any optical geometry. By similarities, the Sony was similar to the original (none with codes or ID). With a major surgery, the new LD was installed, and tested. It did shine!!!. But.. no focusing was possible, again. Unmounted the sony and mounted the Rohm model, conducted to the same road end: laser on, focus not. The sledgehammer came back.
But, while I saw a photo review of this story, a strange little shiny on the laser lens aroused my suspicion. Watching through a 6x zoom other defects appeared. The lens surface was damaged, with a scratch and a barely noticeable opacity.
And here, the savior ManoloMos magically appeared in this thread https://www.diyaudio.com/community/...ed-and-lost-substitution-and-repaired.390773/. The useless KSS was the lens donor that once changed, and with a new Sony LD installed, the focus signal was detected!!!!!!. Yes!!!!.
Followed by hours and hours of settings in grating, axial and radial tilt, LD current, mech adjustments, spindle balancing, the first tracking closed loop could be achieved and a decent RF eye pattern reached.
It was a lot of effort, technical discovering, schematics readings, included the Cd ISO red book studying, a dead, abandonded, misstreated CD player returned to the life.
Today not all the CDs can be readed, the CDR or CDRW usually fail. But, the commercial works in high level.
I´m apologize about my english, but you, patient reader, if reached this part, you will not give importance.
My first visual inspection was the laser power adjust trimmer, suspecting the easy way: full throttle for solve some past failure. And it was, minimum resistance regulation = high current = short laser life. First cause revealed.
The second seeking was for a locked lens or his armature. No news, all was ok. Then, I think, some driver burned, connector or power source out of spec. None of them. All were ok. Next step, resistance of focus and tracking lens coils. Voilá, the focus coils in open circuit, the tracking coils ok (8 ohm). Looking more deeply I found one of the copper tails from the base to the movable part broke, apparently . Second cause was revealed.
Starting with the last issue, I tried to re-weld the broken copper tail, but it was so short and in such a small space that I decided to drop off the 4 tails and replace them with longer wires. The donor was the cable of an apple earbud. After a surgery with magnifying glass, flux, tin soldering iron and patience, all the tails were left reconnected. Silicon glue was applied into welds as an effort dissipator. I had to be very very careful with the rubber suspension. In my opinion, the worst design ever made for lens stabilization (but I´m not a japanese engineer).
I follow. All reassembled, resistance checked (14 ohm focus, 8 ohm tracking), powered on and… the lens goes back to life!!, like a dog wagging its tail. But the laser intensity remained very low. I did not care.3
I put a CD, powered on again, and the focus detection shows began: the nudges for the spindle motor, the swing of lens, the seeking magic sound… but NO DISC fatal error. I did not care. News tests would begin. Laser current measure was 65mA, high, but no so much; power laser measure no possible (who have a pwr meter in this days?). Then a comparison with a healthy cd player, via cell camera, gave low power. Cleaned lens, lubed rails, re-adjusted tilt, but nothing. The fail was the same.
Then, the fact had to be faced: laser diode had to be passed to a better life, and replaced. Here, in a crossroad of change LD or try with other OPU, I took both: buy and replace the laser diode and develop an adaptation for other compatible OPU. The LDs selected were two: SLD105VL from Sony and RLD78MYR1 from Rohm. Why?, both 780nm, 5mW, AKA pinout and they were the best sellers on Aliexpress :|.
The OPU selected was the KSS313. Why?. Because this is cheap, with stock in Argentina and his dimensions appropriated to fit into the carriage, or was it what I expected.
The OPU came first, and surprise: the geometry dont fit any with the carriage… the second crossroads: sacrifice the original carriage or develop a new one, via 3D printing. The second was the election. After hours and hours of measuring, design, trial, re-adjust, the piece was builded.
Regarding the connections between the KSS313 and the board, a cross cable was necessary. The KSS´s flex connector was´nt compatible with the board. When all the parts were mounted and energized, the lens moved, and the LD goes shining. Welll done. A few tests revealed a high current in the KSS´s LD. Why??. Because the RF amplifier, a TA8137 Toshiba has different input sensitivity LD photodiode. Looking for a datasheet, they do not exist on the web (neither deep). Then I emailed Toshiba, and they responded to me (unbelievable!) that this IC wasn´t sold for a massive market and was a special development. Another Pioneer vaulted secret. Investigating other pioneer models, I could see that the issue was the VR for LD power adjustment. The KSS had a 2.2k and the required must be 4.7k. Changed and success!.
With the LD in his comfort zone, the RF signal remained absent. Aghhhh. And now what?. Looking again, I found that the KSS´s PDIC had some contact unsoldered. Surely my KSS OPU was a second hand or surplus. Once corrected this, the RF signal, or some similar, appeared at test point TP1. Yes!!. But not so good. A lot of electrical noise was present as an RF signal. New solutions were applied, shielding, cable re-routing, testing and testing, all resulted unsatisfactory, and discouraging. With a sledge hammer to destroy all in mind, the purchased LDs arrived from China, 4 months after. This is Argentina's style.
The last chance would be the change of LD. The main difference between Sony and Rohm is the focal point. An essential spec for any optical geometry. By similarities, the Sony was similar to the original (none with codes or ID). With a major surgery, the new LD was installed, and tested. It did shine!!!. But.. no focusing was possible, again. Unmounted the sony and mounted the Rohm model, conducted to the same road end: laser on, focus not. The sledgehammer came back.
But, while I saw a photo review of this story, a strange little shiny on the laser lens aroused my suspicion. Watching through a 6x zoom other defects appeared. The lens surface was damaged, with a scratch and a barely noticeable opacity.
And here, the savior ManoloMos magically appeared in this thread https://www.diyaudio.com/community/...ed-and-lost-substitution-and-repaired.390773/. The useless KSS was the lens donor that once changed, and with a new Sony LD installed, the focus signal was detected!!!!!!. Yes!!!!.
Followed by hours and hours of settings in grating, axial and radial tilt, LD current, mech adjustments, spindle balancing, the first tracking closed loop could be achieved and a decent RF eye pattern reached.
It was a lot of effort, technical discovering, schematics readings, included the Cd ISO red book studying, a dead, abandonded, misstreated CD player returned to the life.
Today not all the CDs can be readed, the CDR or CDRW usually fail. But, the commercial works in high level.
I´m apologize about my english, but you, patient reader, if reached this part, you will not give importance.
Attachments
Alpair 10.2 peak at 8khz
- By bchang
- Full Range
- 22 Replies
Hi! I posted earlier for help with an MLTL that I built for the Alpair 10.2. I'm very happy with the sound, but have been using DSP to tame a peak at 8khz. I've done lots of measurements and am confident that the peak is in the driver, not the cabinet. Does any one know of a physical way to reduce that peak? Thanks in advance!
Counterpoint-SA220-pwr to Exicon mosfet 10N20 10P20 TO3
- By William0401
- Solid State
- 84 Replies
Attachments
What is the name of this design
- By maxolini
- Subwoofers
- 8 Replies
Guys,
What is the name of this design
Bandpass?
The CSA of the mouth opening affects what part of the freq response
What is the name of this design
Bandpass?
The CSA of the mouth opening affects what part of the freq response
Manley Stingray with factory upgrades
I am selling my Stingray integrated amp for $3,300 shipping included in the lower 48 only. It comes with an additional set of Mullard output tubes. I had three options added from Manley:
1) Triode/Ultralinear output can now be chosen by a switch for each channel.
2) Sub out added for each channel.
3) Tape out added for each channel.
40~50 WPC utralinear, 23 WPC triode. Separate controls for each channel. weighs 30 lbs.
Original packing materials and Manley tubes included.
Also, ad can be seen in more detail at US Audio Mart.
1) Triode/Ultralinear output can now be chosen by a switch for each channel.
2) Sub out added for each channel.
3) Tape out added for each channel.
40~50 WPC utralinear, 23 WPC triode. Separate controls for each channel. weighs 30 lbs.
Original packing materials and Manley tubes included.
Also, ad can be seen in more detail at US Audio Mart.
Attachments
HK670 Repair
- By Kevviek
- Solid State
- 5 Replies
I’m having a look at a HK670 from 2001 for my brother-in-law.
The symptom is intermittent cutting out of both channels. I’ve searched forums and can’t find a common fault, but have a few starting points.
Two of the caps are bulging and one of the resistors looks to have some corrosion in the leads, so they will be replaced first.
Curious though, I have got the service manual and there’s a marking I’ve never seen before for a cap in a circuit. What does “562M” mean?
The symptom is intermittent cutting out of both channels. I’ve searched forums and can’t find a common fault, but have a few starting points.
Two of the caps are bulging and one of the resistors looks to have some corrosion in the leads, so they will be replaced first.
Curious though, I have got the service manual and there’s a marking I’ve never seen before for a cap in a circuit. What does “562M” mean?
For Sale BA3 Gain stage and populated F4
- By stretchneck
- Swap Meet
- 3 Replies
£80 for BA3 with recommended mosfets and £120 for the pair of populated F4 board + P&P.
I think I have the heatsinks for the BA3 if I look around....
I think I have the heatsinks for the BA3 if I look around....
SEAS EXOTIC F8 speaker build
- By gcl
- Full Range
- 67 Replies
There does not seem to be much information from builders using the SEAS Exotic F8 so here goes. Following on from my satisfaction with the Hemp FR8 reflex enclosure I made in March 2021 I wanted to build what I hoped would be an even higher quality one. I settled on the SEAS Exotic F8 for this.
I considered horn and reflex designs for this project but concluded that the closed box would be the best for the present location. The design is basically the 60L closed box in the SEAS data sheet but I altered the dimensions slightly to better suit my den (small room converted from garage).
I drew up the panel dimensions and routing for joints and got all parts cut by a firm specialising in routing sheet materials. The enclosure is 18mm Birch ply with double thickness front and back panels. The bracing is MDF. The reason to get the work done professionally was that the internal bracing has hundreds of holes. I estimated it would take a week working with hole-saw or router and producing huge amount of dust so it was an easy decision. Assembling the speaker then was a pleasant task which took a week to complete. I intended to make it permanently sealed by gluing all parts so I had to make a good estimation of the damping required. I had a lot of light polyester mesh which I judged to be suitable. I put a layer internally behind the cross braces and a layer round the drive unit part of the enclosure. There is some additional thickness from random pads. The enclosure was painted and the front panel varnished before joining the two together. The finish is the same as for the Hemp enclosure. These builds are not regarded as pieces of furniture and I don’t want them to be veneered. They are for use in my den so function is the aim. I am happy with the varnished fronts and the grey painted enclosure. The finish is perfectly acceptable and very easy to do.
The total cost of the speakers was £1650 in June 2021.
The sound was as expected initially very bright and forward and revealing of detail though thin at the lower range. They are very easy to adjust to your liking in situ as the tuning is done by components in the speaker leads. I added an inductor and resistor as SEAS suggest and then adjusted these values after careful positioning of the speakers in the room.
After months of listening I am very happy with them indeed. They are still a work in progress as I can tweak them. I have a few inductors and resistors wired up with switches to allow easy substitutions. I will also make some spiked stands to see the effect.
I considered horn and reflex designs for this project but concluded that the closed box would be the best for the present location. The design is basically the 60L closed box in the SEAS data sheet but I altered the dimensions slightly to better suit my den (small room converted from garage).
I drew up the panel dimensions and routing for joints and got all parts cut by a firm specialising in routing sheet materials. The enclosure is 18mm Birch ply with double thickness front and back panels. The bracing is MDF. The reason to get the work done professionally was that the internal bracing has hundreds of holes. I estimated it would take a week working with hole-saw or router and producing huge amount of dust so it was an easy decision. Assembling the speaker then was a pleasant task which took a week to complete. I intended to make it permanently sealed by gluing all parts so I had to make a good estimation of the damping required. I had a lot of light polyester mesh which I judged to be suitable. I put a layer internally behind the cross braces and a layer round the drive unit part of the enclosure. There is some additional thickness from random pads. The enclosure was painted and the front panel varnished before joining the two together. The finish is the same as for the Hemp enclosure. These builds are not regarded as pieces of furniture and I don’t want them to be veneered. They are for use in my den so function is the aim. I am happy with the varnished fronts and the grey painted enclosure. The finish is perfectly acceptable and very easy to do.
The total cost of the speakers was £1650 in June 2021.
The sound was as expected initially very bright and forward and revealing of detail though thin at the lower range. They are very easy to adjust to your liking in situ as the tuning is done by components in the speaker leads. I added an inductor and resistor as SEAS suggest and then adjusted these values after careful positioning of the speakers in the room.
After months of listening I am very happy with them indeed. They are still a work in progress as I can tweak them. I have a few inductors and resistors wired up with switches to allow easy substitutions. I will also make some spiked stands to see the effect.
Akita "AllInOne" Amp based on TPA325x PFFB+ and LLC PSU in one board.
- By drMordor
- Group Buys
- 1602 Replies
Attachments
For Sale (Balanced) Iron Pre Essentials Kit + a few components
- By carsten.witt
- Swap Meet
- 2 Replies
Hi
I have too many projects and too little time, so I am selling my IP with a few suitable components.
Parts:
All is unused and comes in the original packaging from the store or DigiKey (please see pic)
Cost all together (what is on the pic): 200€ + shipping
Shipping costs by arrangement.
For the time being only EU members (except UK, sorry to much customs paper work)
Links:
Thread: https://www.diyaudio.com/community/...e-register-your-interest.390509/#post-7128942
Store (Sold out): https://diyaudiostore.com/products/iron-pre?_pos=6&_sid=3d084349f&_ss=r
I have too many projects and too little time, so I am selling my IP with a few suitable components.
Parts:
- 16 x UFG1E221MPM (14,64€ - OBSOLET PART)
- 2 x UHE1V471MHD& (1,88€)
- 4 x 3296W-200LF (10,66€)
- 4 x 3296W-1-472LF (10,66€)
All is unused and comes in the original packaging from the store or DigiKey (please see pic)
Cost all together (what is on the pic): 200€ + shipping
Shipping costs by arrangement.
For the time being only EU members (except UK, sorry to much customs paper work)
Links:
Thread: https://www.diyaudio.com/community/...e-register-your-interest.390509/#post-7128942
Store (Sold out): https://diyaudiostore.com/products/iron-pre?_pos=6&_sid=3d084349f&_ss=r
Leak Stereo 70 question
- Solid State
- 11 Replies
Hi All,
First post. Hope everyone is well. I am about to start repairing my dads Leak 70 amplifier however he also had my late Uncles Stereo 70 which 'didn't work' - I got this first as a trial run to get familiar with the insides and the schematics, with no risk of any further damage to my dads when Is I start on it. My uncles one was deemed to be gubbed beyond repair, however I noticed very quickly there was no DC voltage getting to it, then noticed that there was no way it could since there was a small bracket thing mounted on the transformer body (3 pin) with a leg going to the transformer and the other leg going to the diodes. There was no connection between the two, so basically it would never work. This was not reflected on the schematic I had or most pictures I could find of the transformer which showed no such 'interruption' to the circuit.
I eventually found an image showing this part and an alternative schematic also showing it, a green part that looked a bit like a high wattage resistor but I assumed it was a thermal fuse. The transformer in my uncles amp had clearly been replaced (also had a date code sticker of the year of his passing) so I think that someone has replaced the transformer but not fitted the part in question. I linked the two pins and hey presto, amp working well and sounding great.
So the question is, what is this part ? Is it a thermal fuse ? If so was this just a bodge to get around UL standards that came out stating transformers had to have one (I think for northern US and Canada), the schematic I have which includes it perhaps refers to it as a Temperature compensation diode? If it is a Thermal fuse, I fail to see how it could ever get hot enough to pop given it is not in contact with the transformer windings (I believe the common way of incorporating these is in the windings. Picture of the missing part attached (the green part).
Many thanks!
First post. Hope everyone is well. I am about to start repairing my dads Leak 70 amplifier however he also had my late Uncles Stereo 70 which 'didn't work' - I got this first as a trial run to get familiar with the insides and the schematics, with no risk of any further damage to my dads when Is I start on it. My uncles one was deemed to be gubbed beyond repair, however I noticed very quickly there was no DC voltage getting to it, then noticed that there was no way it could since there was a small bracket thing mounted on the transformer body (3 pin) with a leg going to the transformer and the other leg going to the diodes. There was no connection between the two, so basically it would never work. This was not reflected on the schematic I had or most pictures I could find of the transformer which showed no such 'interruption' to the circuit.
I eventually found an image showing this part and an alternative schematic also showing it, a green part that looked a bit like a high wattage resistor but I assumed it was a thermal fuse. The transformer in my uncles amp had clearly been replaced (also had a date code sticker of the year of his passing) so I think that someone has replaced the transformer but not fitted the part in question. I linked the two pins and hey presto, amp working well and sounding great.
So the question is, what is this part ? Is it a thermal fuse ? If so was this just a bodge to get around UL standards that came out stating transformers had to have one (I think for northern US and Canada), the schematic I have which includes it perhaps refers to it as a Temperature compensation diode? If it is a Thermal fuse, I fail to see how it could ever get hot enough to pop given it is not in contact with the transformer windings (I believe the common way of incorporating these is in the windings. Picture of the missing part attached (the green part).
Many thanks!
Bamberg Audio Closing
- By audiobomber
- Multi-Way
- 1 Replies
I received the below email today. I still own, still love, the S5-MTM standmounts I purchased in 2005. They have been in daily use ever since. They sound amazing!
Bamberg Audio, "Speakers For Life", indeed. Thanks for everything, Phil, best of luck in your retirement:
Hello all,
I have decided to retire my efforts with Bamberg speakers. Thank you to everyone who has purchased any of my designs, and for the support and positive feedback you provided me with over the years.
To this end, I have just three sets of speakers left in stock, and they are listed on the Sale Page.
The website will end on April 30, 2024. But you may reach me directly at pebamberg@gmail.com.
With respect and appreciation,
Philip Bamberg
Bamberg Audio, "Speakers For Life", indeed. Thanks for everything, Phil, best of luck in your retirement:
Hello all,
I have decided to retire my efforts with Bamberg speakers. Thank you to everyone who has purchased any of my designs, and for the support and positive feedback you provided me with over the years.
To this end, I have just three sets of speakers left in stock, and they are listed on the Sale Page.
The website will end on April 30, 2024. But you may reach me directly at pebamberg@gmail.com.
With respect and appreciation,
Philip Bamberg
http://BambergAudio.com
Bamberg Audio on Facebook
Sale page
Fan inside audio chassis: variable speed, temperature controlled, analog - No PWM
- By Mark Johnson
- Solid State
- 55 Replies
Attachments
Stealing the output from a DAC chip (Topping D30 CS4398)
- By piecor
- Digital Source
- 9 Replies
I have a DAC that sounds very good to me, it's the Topping D30. The chip is the CS4398, a chip that I have listened to in several implementations and always found it very musical.
I would like to try to improve the output stage. I have several ideas in mind (transformers or tubes). As a first step I should steal the analog signal at the output of the chip. Below in photo I show the PCB. The red arrows indicate the points connected to the positive/negative output pins of the two channels.
What do you think is the best way to get the signal? Try soldering the wires to the pins directly? Or act on the four holes indicated by the arrows? In the latter case I guess it is easier, but I don't know how to remove the blue layer covering the conductor. I would be very happy if someone could point me to the right technique.
I would like to try to improve the output stage. I have several ideas in mind (transformers or tubes). As a first step I should steal the analog signal at the output of the chip. Below in photo I show the PCB. The red arrows indicate the points connected to the positive/negative output pins of the two channels.
What do you think is the best way to get the signal? Try soldering the wires to the pins directly? Or act on the four holes indicated by the arrows? In the latter case I guess it is easier, but I don't know how to remove the blue layer covering the conductor. I would be very happy if someone could point me to the right technique.
Aiwa AA8700 bias adjustment
- By peterpl
- Solid State
- 39 Replies
Hi, I have a problem with adjusting bias on my Aiwa AA8700 amplifier,
Service manual says that you should connect a probe to TP6 ( it is on emitter of Q8) and reach 23mV turning SFR2 potentiometer. The value of that pot. is 100R.
Actually, after warming up, I have like 66mV and turning SFR2 gives nothing ( maybe +- 1mV).
This is on the right channel. On the left channel which is the same I have like only 1mV and also turning a potentiometer has no reaction.
I thought that maybe the pot is broken so i replaced them but no change.
Maybe I should put a bigger value potentiometer ?
This pot is between transistors Q4=2SB648A and Q5=2SD668A maybe they should be replaced but for what ?
There’s also diode D6=STV-4H acting as temperature sensor ( it is attached to heat sink) the diode looks ok, passes the diode test but now that diode can be replaced by a transistor e.g. BC550 + 3K3 and 1k resistors.
What do you guys think I should do ?
Service manual says that you should connect a probe to TP6 ( it is on emitter of Q8) and reach 23mV turning SFR2 potentiometer. The value of that pot. is 100R.
Actually, after warming up, I have like 66mV and turning SFR2 gives nothing ( maybe +- 1mV).
This is on the right channel. On the left channel which is the same I have like only 1mV and also turning a potentiometer has no reaction.
I thought that maybe the pot is broken so i replaced them but no change.
Maybe I should put a bigger value potentiometer ?
There’s also diode D6=STV-4H acting as temperature sensor ( it is attached to heat sink) the diode looks ok, passes the diode test but now that diode can be replaced by a transistor e.g. BC550 + 3K3 and 1k resistors.
What do you guys think I should do ?
USB transport I2S 32bit/384kHz, DSD512, multichannel Out 4xI2S, stereo In I2s, surround up to 16-channels (TDM mode)
- By topdevice
- Vendor's Bazaar
- 16 Replies
There are two of them. They're called Reflex 2.0 & Reflex 3.0
Ask me!
Oleg
ChipDipDAC
KiCad projects:
Reflex2.0
Reflex3.0
Chip Studio v0.99.5 (19/03/2024)
ChipUpdater_v1.2
firmware Reflex_2.0_v2.4
firmware Reflex_3.0_v2.4
- Playback of PCM format with a maximum sampling frequency of 762 kHz 32 bit, DSD512 native or DSD256 DoP playback.
- Playback of S/PDIF - 384kHz
- Plays multi-channel Surround audio in PCM format.
- Recording stereo sound with studio quality with a maximum sampling frequency of 762 kHz 32 bit
- Two I2C ports for controlling external DACs and ADCs
- Two SPI ports for controlling external DACs and ADCs
- Addressable LED (Neopixel) control port
- Thirty two GPIO pins for connecting external controls and indications (potentiometers, buttons, switches, LEDs, encoders)
- Programmable using ChipStudio, SigmaStudio, PurePathStudio software
- Hardware adjustments
- Free change of USB Vid/Pid
- ASIO drivers from any third-party manufacturers
- Master with internal sync
- Master with external sync
- Slave
| Configuration Surround audio | PCM, kHz | DSD256 DoP | DSD512 native | |||||||||||||||||||||||||||||||||||||||
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| Until 11 289,6 | Until 22 579,2 | |||||||||||||||||||||||||||||||
2.0 | + | + | + | + | + | + | + | + | + | + | + | + | ||||||||||||||||||||||||||||||
3.1 | + | + | + | + | + | + | + | + | ||||||||||||||||||||||||||||||||||
4.0 | + | + | + | + | + | + | + | + | ||||||||||||||||||||||||||||||||||
5.1 | + | + | + | + | + | + | ||||||||||||||||||||||||||||||||||||
7.1 | + | + | + | + | + | + | ||||||||||||||||||||||||||||||||||||
12 channels | + | + | + | + | ||||||||||||||||||||||||||||||||||||||
16 channels | + | + | + | + |
Ask me!
Oleg
ChipDipDAC
KiCad projects:
Reflex2.0
Reflex3.0
Chip Studio v0.99.5 (19/03/2024)
ChipUpdater_v1.2
firmware Reflex_2.0_v2.4
firmware Reflex_3.0_v2.4
First HiFi Tube amp
- By Orion24
- Tubes / Valves
- 134 Replies
Hello everyone 🙂
I only have guitar amp experience so hifi its the first time, i made a schematic and i'm gonna need help to confirm it if possible:
The first part (The preamp) is an existant project from "diyaudioprojects.com" so this one is ok but i'm not sure about the phase inverter do you see an issu there ?
There is also no feedback do you think i need one and where should it be, around R7 (like in guitar amps) or maybe R4 ?
I made also the first version of the power supply, well its a bit exotic 😆
Thank you for your help
Alexis
I only have guitar amp experience so hifi its the first time, i made a schematic and i'm gonna need help to confirm it if possible:
The first part (The preamp) is an existant project from "diyaudioprojects.com" so this one is ok but i'm not sure about the phase inverter do you see an issu there ?
There is also no feedback do you think i need one and where should it be, around R7 (like in guitar amps) or maybe R4 ?
I made also the first version of the power supply, well its a bit exotic 😆
Thank you for your help
Alexis
For Sale Used Black Gate standard polarized capacitors
- By madisonears
- Swap Meet
- 3 Replies
Attachments
TI DACx1001 discussion - I2S input, Vref etc
- By lasercut
- Digital Line Level
- 31 Replies
Im planning to build a DAC11001B based DAC and will share any progress here inc. measurements, aiming for uncompromised measured performance from the chips.
First, I wanted to see if the suggested 24bit RJ glue logic for DAC11001 could be adapted to work with a normal I2S input.
After a read of the datasheet, I attempted to simulate it (the first frame of the sim has an error):
The DACx1001 wants the audio data left justified to the 23rd bit and an 8 bit shift register will shift the I2S MSB accordingly, sound about right?
Something I'm trying to understand is why the main shift register has 2 inputs held high instead of one.
I think it could be to have a longer LDAC pulse so that the LDAC minimum low time (20ns) is satisfied even at the highest clock rates,
however the shift register output also drives the XOR and it causes the audio data MSB to be inverted.
This couldnt be right, so I figured instead the shift register output may be delayed by 1 bit because of some hidden issue in the sim.
If this proposed delay is corrected the input data will no longer be effected, but this changes the register address from DAC-DATA (01h) to DAC-CLEAR-DATA (03h) and this doesn't seem right either:
Can anyone clarify this?
Few other small things I managed to figure out about the glue logic circuit that may not be obvious to everyone:
DAC will be sensitive to BCLK jitter, as the LDAC pulse is clocked out of shift register by BCLK.
The circuit should be directly compatible with the 18 and 16 bit versions of the chip.
First, I wanted to see if the suggested 24bit RJ glue logic for DAC11001 could be adapted to work with a normal I2S input.
After a read of the datasheet, I attempted to simulate it (the first frame of the sim has an error):
The DACx1001 wants the audio data left justified to the 23rd bit and an 8 bit shift register will shift the I2S MSB accordingly, sound about right?
Something I'm trying to understand is why the main shift register has 2 inputs held high instead of one.
I think it could be to have a longer LDAC pulse so that the LDAC minimum low time (20ns) is satisfied even at the highest clock rates,
however the shift register output also drives the XOR and it causes the audio data MSB to be inverted.
This couldnt be right, so I figured instead the shift register output may be delayed by 1 bit because of some hidden issue in the sim.
If this proposed delay is corrected the input data will no longer be effected, but this changes the register address from DAC-DATA (01h) to DAC-CLEAR-DATA (03h) and this doesn't seem right either:
Can anyone clarify this?
Few other small things I managed to figure out about the glue logic circuit that may not be obvious to everyone:
DAC will be sensitive to BCLK jitter, as the LDAC pulse is clocked out of shift register by BCLK.
The circuit should be directly compatible with the 18 and 16 bit versions of the chip.
-
Locked
For Sale TD-124 Turntable (The original series not MKII)
I am selling vinyl related hardware, first up is my old TD-124.
This is what I would refer to as an unrestored but heavily refurbished TD-124. Short of the chassis and motor everything else had to acquired to restore it to running order. Most components are original Thorens, there are some significant improvements.
*The slip platter brake needs pads and to be adjusted to be functional. It does not have the 45rpm integrated adaptor. *
This table has its original E50 which I serviced more than a decade ago (and have lubricated periodically). Note that the eddy current brake is adjusted for 120V+ AC mains, and that reduced voltage (110V - 115V) will allow you to ease off on the eddy current brake which results in quieter running.
It has Hanze HI-Fi motor suspension springs, and the an Audio-Silente idler.
It has the more desirable Thorens OEM cast iron platter. It is equipped with a Gem Dandy Cork & rubber mat.
Short mp4 files of it running are attached.
The wiring to the switch and neon lamp has been replaced.
It comes with a plywood plinth mass loaded with roughly 10lbs of lead shot capped off with epoxy. It also comes with multiple arm boards including 2 that are suitable for use with Jelco 12 inch arms like the 750, 850, and 950...
The TD-124 is PICK UP ONLY, and I will accept cash, PayPal Friends & Family, bank transfer, and certified checks in the amount of $850. I am located just a couple of miles south of Boston, MA. I will NOT ship this item. The price isn't negotiable and I am not interested in trades as I am trying to reduce my collection of misfit toys. 😀
This is what I would refer to as an unrestored but heavily refurbished TD-124. Short of the chassis and motor everything else had to acquired to restore it to running order. Most components are original Thorens, there are some significant improvements.
*The slip platter brake needs pads and to be adjusted to be functional. It does not have the 45rpm integrated adaptor. *
This table has its original E50 which I serviced more than a decade ago (and have lubricated periodically). Note that the eddy current brake is adjusted for 120V+ AC mains, and that reduced voltage (110V - 115V) will allow you to ease off on the eddy current brake which results in quieter running.
It has Hanze HI-Fi motor suspension springs, and the an Audio-Silente idler.
It has the more desirable Thorens OEM cast iron platter. It is equipped with a Gem Dandy Cork & rubber mat.
Short mp4 files of it running are attached.
The wiring to the switch and neon lamp has been replaced.
It comes with a plywood plinth mass loaded with roughly 10lbs of lead shot capped off with epoxy. It also comes with multiple arm boards including 2 that are suitable for use with Jelco 12 inch arms like the 750, 850, and 950...
The TD-124 is PICK UP ONLY, and I will accept cash, PayPal Friends & Family, bank transfer, and certified checks in the amount of $850. I am located just a couple of miles south of Boston, MA. I will NOT ship this item. The price isn't negotiable and I am not interested in trades as I am trying to reduce my collection of misfit toys. 😀
Otari CTM-10
- By Gene49
- Everything Else
- 0 Replies
Wondering if anyone might have any information on the old (1986 era) Otari CTM-10S/10R broadcast cart machine units. Very hard to find any info on it. Looking for the connector pin outs, operating/service information if possible. Any help greatly appreciated!
Help with Fostex’s Newer FE103NV2 Thiele/Small Parameters
- By Jeffrey 01
- Full Range
- 3 Replies
Attachments
My first passive crossover design!
I recently made a post trying to get some information on how to design a crossover as I had previously no knowledge on how to and wanted to renovate some speaker cabinets and remake a crossover to do this. To inform my design I used frequency and impedance graphs from the manufacturers. I know this doesn't deliver the best results as the boxes used for these tests aren't the same as the one that I'll be using for my speakers. Nonetheless I decided to use them as I don't have the equipment to make my own graphs. Here are the data sheets for the drivers that I used; Bass driver: https://www.farnell.com/datasheets/2623802.pdf , Horn driver: https://www.parts-express.com/pedocs/specs/290-5634--eminence-f110m-8-spec-sheet.pdf and tweeters: https://doc.soundimports.nl/pdf/brands/GRS/DTM-8/DTM-8 Specifications.pdf. Here is the resulting circuit
And the resulting graphs from this
I can tell from the frequency graph that the tweeters aren't doing a lot, now I'm not sure if this is from how I've tried to link them in parallel or how my attempt at a Zobel network has affected the level of these drivers. Or whether it is a good idea to have them connected at all or if I should just use the horn and bass drivers to make the speakers. Any advice on how I can better improve this design or use this design to inform another design would be greatly appreciated!
And the resulting graphs from this
I can tell from the frequency graph that the tweeters aren't doing a lot, now I'm not sure if this is from how I've tried to link them in parallel or how my attempt at a Zobel network has affected the level of these drivers. Or whether it is a good idea to have them connected at all or if I should just use the horn and bass drivers to make the speakers. Any advice on how I can better improve this design or use this design to inform another design would be greatly appreciated!
For Sale UGS - Muse Edition Bare boards
Attachments
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UGS - Muse Edition (4).jpg -
UGS - Muse Edition (5).jpg -
UGS - Muse Edition (6).jpg -
UGS - Muse Edition (7).jpg -
UGS - Muse Edition (8).jpg -
UGS - Muse Edition (9).jpg -
UGS - Muse Edition (10).jpg -
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UGS - Muse Edition (12).jpg -
UGS - Muse Edition (13).jpg -
UGS - Muse Edition (14).jpg
Supravox drivers? Any opinions?
- By noamgeller
- Multi-Way
- 7 Replies
If someone can elaborate on this supravox driver I would appreciate it very very much.
Why is it special?
Why doe it costs 1500€
And how does Cessaro build their opus one out of it 😉
Why is it special?
Why doe it costs 1500€
And how does Cessaro build their opus one out of it 😉
For Sale McIntosh Labs MQ 107 Environmental Equalizer, Capacitor kit, and Manual.
Asking $750 but open to offers. Call or text (601) 551-9453.
I'd like a better alternative "horn" for PRV 10FR300 than
- By freddi
- PA Systems
- 1 Replies
Attachments
PCB DIY Art Journey-Creating a 7.1 Home Theater.
Hello everyone, the sentences in the article may not read smoothly because my English level is not high and it was translated using software. However, we have common interests and hobbies,, we love music, DIY, and life.
A month ago, I planned to build a movie theater in my room so that I could watch movies happily.
So I bought a projector and a 150-inch curtain. But the sound effects are not exciting and happy enough. If I bought off the shelf amps and speakers the price would be out of my budget. Since I like electronic products, I have experience in DIY computers before. and was able to achieve my goals and expectations within a limited budget. Thus, the idea of DIY amplifier equipment and speakers was born.
First of all, I chose TDA7850 as the type of power amplifier chip, which supports 4 independent amplification channels. Two such chips can have 8 channels. Realize 7.1 panoramic sound system.
After learning more about the 7850 amplifier on the Internet, I ordered two PCB motherboards. As well as the required capacitors, inductors, connectors, power supplies, wires, speaker units, boxes, and tools needed for manufacturing.
Amplifier PCB and audio input filter mainboard, some capacitors and resistors, and wires.
The multimeter is used to detect whether the circuit, voltage and current are normal. My plan is to use a wooden box to place two power amplifier motherboards, as well as a prescaler and an audio input filter. Therefore, a 7 cm fan is prepared, and the temperature controller is used to control the starting fan to dissipate heat.
6.5-inch woofer,
3-inch midrange unit,
1-inch tweeter
The total power of the power supply is 350 watts. It can connect three devices at the same time, with rated voltage of 15V and maximum output current of 23.3A. I only use it to connect two devices, so the maximum current that each device can get is about 11.56A, which meets the power required by each power amplifier.
Some accessories arrived first, and some are still on the way.
Start soldering some components of the amplifier motherboard. Others will be installed after the courier arrives.
In order to facilitate the replacement of different capacitors later and have different sound effects, I prepared a base for the capacitors.
Only 20 attachments can be uploaded, so I will publish them at the next level later.
A month ago, I planned to build a movie theater in my room so that I could watch movies happily.
So I bought a projector and a 150-inch curtain. But the sound effects are not exciting and happy enough. If I bought off the shelf amps and speakers the price would be out of my budget. Since I like electronic products, I have experience in DIY computers before. and was able to achieve my goals and expectations within a limited budget. Thus, the idea of DIY amplifier equipment and speakers was born.
First of all, I chose TDA7850 as the type of power amplifier chip, which supports 4 independent amplification channels. Two such chips can have 8 channels. Realize 7.1 panoramic sound system.
After learning more about the 7850 amplifier on the Internet, I ordered two PCB motherboards. As well as the required capacitors, inductors, connectors, power supplies, wires, speaker units, boxes, and tools needed for manufacturing.
Amplifier PCB and audio input filter mainboard, some capacitors and resistors, and wires.
The multimeter is used to detect whether the circuit, voltage and current are normal. My plan is to use a wooden box to place two power amplifier motherboards, as well as a prescaler and an audio input filter. Therefore, a 7 cm fan is prepared, and the temperature controller is used to control the starting fan to dissipate heat.
6.5-inch woofer,
3-inch midrange unit,
1-inch tweeter
The total power of the power supply is 350 watts. It can connect three devices at the same time, with rated voltage of 15V and maximum output current of 23.3A. I only use it to connect two devices, so the maximum current that each device can get is about 11.56A, which meets the power required by each power amplifier.
Some accessories arrived first, and some are still on the way.
Start soldering some components of the amplifier motherboard. Others will be installed after the courier arrives.
In order to facilitate the replacement of different capacitors later and have different sound effects, I prepared a base for the capacitors.
Only 20 attachments can be uploaded, so I will publish them at the next level later.
Coherers, Acoustic Lenses, Phase shields and more
- By Michael1103
- Multi-Way
- 4 Replies
Recently I've been building a small bookshelf speaker for myself and I came across the research performed by Purifi Audio. In the SPK16 speaker, the tweeter has constant directivity from 2khz to 20khz with only a -6db loss at 60 degrees. this is a very impressive feat of engineering. Using a one inch tweeter like they are using, the driver begins to beam at around 10khz, meaning the response below that can be controlled with a waveguide. I've been able to optimize a waveguide to hit the same result below 10khz, but once we hit the beaming frequency the speaker narrows from -6 at 60 degrees to about -6 at 30 degrees. In their log, Purifi documents that they increased the directivity of the tweeter by using a "coherer" which looks much like a lens, or a phase shield. They state "a collection of ring-shaped objects that shape the wavefront around the throat of the wave guide in order to direct energy to the further of axis directions"
My question is, what principle does this "coherer" operate on?
Could it be that the rings are creating points of diffraction which spread out the highest frequencies?
https://purifi-audio.com/blog/tech-notes-1/spk16-reference-design-12
My question is, what principle does this "coherer" operate on?
Could it be that the rings are creating points of diffraction which spread out the highest frequencies?
https://purifi-audio.com/blog/tech-notes-1/spk16-reference-design-12
How to convert the output to Digital?
- By El3ctroniks
- Electronic Design
- 8 Replies
HI, i am using the circuit(in picture) for making a piezoelectric contact mic. I got this circuit from link. i am building a digital stethoscope and the frequencies of interest are 5-20 Hz.
My problem is that I now need to digitize this signal to be able to process it. I simulated the circuit in LTSpice, and these are the results:
Can anyone tell me how I can proceed to digitize any signal received from the pre amplifier?
Which amplifier and ADC can i use to convert the signal into digital format? My frequencies of interest are 5-20 Hz
My problem is that I now need to digitize this signal to be able to process it. I simulated the circuit in LTSpice, and these are the results:
Can anyone tell me how I can proceed to digitize any signal received from the pre amplifier?
Which amplifier and ADC can i use to convert the signal into digital format? My frequencies of interest are 5-20 Hz
