For Sale, Sparkos Labs discrete dual opamps SS3602

Netherlands & Europe buyers preferred.
Total of 4 available.
1 for EUR 59, 2 for EUR 109, 3 for EUR 155, 4 for EUR 200

Selling the following drivers:

Fostex FE208EZ New $180: https://www.ebay.com/itm/276277053223
Visaton B200 Used Mint $80: https://www.ebay.com/itm/276277069278
Visaton TL16H New $180: https://www.ebay.com/itm/276277057230
EV T35 Used Mint $50: https://www.ebay.com/itm/276277063723
18Sound 18W1300 New $200: https://www.ebay.com/itm/276276851568
Faital 18FH500 New $140: https://www.ebay.com/itm/276276854453
LaVoce WSF121.70g New $50: https://www.ebay.com/itm/276277065743

Speaker builders dream. Selling several hundred dollars worth of new drivers from Visaton, BMS, and Dayton. $50 starting price: https://www.ebay.com/itm/276284794391.

Does anyone have experience with Airborne FR222B8-19F full range driver? I'm thinking about trying them out in a vintage stereo console rework and have 2 main questions.

1)I'm interested if anyone has measured the TS parameters at home.

2)With the 5k dip, I'm thinking that after I shape the response above and below the dip creating a downward slope towards 15khz, the 5k dip will only be down 5db and that might be more than acceptable.

Thanks!

FS: HiFiBerry DSP Add-On Board for variety of HiFiBerry DACs. Asking $30. PM me for details.

At Shinjitsu Audio, our choice of using a Full Range (FR) driver like the Mark Audio CHR120 is grounded in its unique capabilities. Beyond the crossover point, situated around 2K, this driver maintains linearity for approximately 2 octaves beyond the crossover rolloff. This characteristic sets it apart from standard mid-woofers or woofers, which often experience roll-off or breakup before reaching the crossover, necessitating sufficient attenuation to keep the breakup mode at a low volume. The advantage lies in the FR driver's ability to stay linear, coherent, and low in distortion as it seamlessly hands off the signal to the horn. Regarding the CD resistor, it employs a standard L Pad configuration, with the parallel leg positioned atop the cabinet to allow for adjustable attenuation. While our enclosed crossover within the cabinet already incorporates horn high-frequency compensation, addressing the natural high-frequency rolloff of horns beyond 10k. This ensures a well-balanced and compensated audio output.

Want to buy a pair of this tweeter.

FOCAL TA451


It can be the model TA452 too, if someone has 2 of these for sale.

Thanks.

Hi,
I would like to build 3-way stereo speakers, probably active with a Hypex FA253. From browsing the forum (thank you all) I already have a few ideas about which chassis would be suitable, but I haven't decided yet. If one is better than another, it may be more expensive. If it's more a matter of personal taste, I would choose the one that is more visually appealing or cheaper. Unfortunately I can't say much about the taste. We're currently listening to a Granduetta. We like the Eton ER4 better than the Eton 26HD3. Otherwise we haven't heard much yet. The taste in music is very broad, including rock, pop, classical, blues and a bit of home cinema.

That is what is already certain:

• not bigger than Granduetta (180L)
• bass response able to produce chest kicks
• sound good in a large area of the room
• not too complicated to design the active filter
• sound very good quietly

I built a CNC milling machine to build the Granduetta housing, so I would also like to build the future cabinets myself. The CAD Construction, Cutting, Gluing is a lot of fun for me, so if it makes sense, I would mill a 3D wave diffuser and stick it to the inside wall or any idea you may have, but i think we should first choose the drivers.
I got an umik-1 microphone to measure something.

I find these speaker drivers interesting:



If a chassis requires little volume, I would also take into consideration to use several per speaker. My tendency is towards the Accuton version, but I haven't heard any of these drivers.

I hope that I have presented it clearly and that you have fun following the progress. I'm curious what you have to say about it.
Kind regards

Hi, Would a Normally Open Relay be better then normally closed for Speaker connection, avoiding " contact sticking" ?. Tho , the more I think it would make no difference than using normally closed or than using just one Relay.

Hello, anyone did DC detector with a comparator and a ref voltage ?. Something like this.
( two op amps for + and - rail detection. )
Even at 40v at 5 hz won't " trigger it " so no false dc detection.

I need to replace one of the four 2SB554 transistors in an Adcom GFA-555II power amplifier.
Each transistor is connected through a 0.22-ohm resistor for current sharing and bias stability.
Do I need to replace all four with balanced transistors or can I replace just the one defective transistor?

Thanks for all your help.

I was wondering if anyone else would try to do this to these transistors.

Hello dear diyaudio friends

For sale is a hifidiy.net A20 class A amplifier (mini-A) assembled kit, this is a Krell clone

One of the channels works perfectly and is stably biased to 240mA, the other channel could not be stably biased.
I don't know where the problem is, I have no time to further investigate.

Sale includes following:

2 x assembled amplifier PCBs (one working, one not working)
1 x assembled power supply PCB
1 x bare preamp PCB
1 x power transformer


Price for the complete amp kit: 50 Euro or 35 Euro without transformer


I’m also willing to trade for one or more of the following items:

(Of course, I will pay difference in value)
Manufacturer sealed bags of:

• 2SJ74-BL
• 2SK170-GR
• 2SJ74-GR
• 2SK370-BL

And maybe other rare signal JFETS or dual JFETS

• BurrBrown PCM1704-K DAC chips
• Analog Devices MAT02 and MAT03 dual monolithic transistors
• 2 x Starkrimson® Ultra Amp Module
• XRK Audio RTR TPA3255 Reference Class D amplifier

Please also take a look at my other offers in the Swap Meet

Shipping:

I will ship anywhere in the world

Everything together with transformer weights approximately 4,1KG, so I can fit everything into a package up to 5KG.
Without the transformer I can fit everything into a 2KG package.
So the costs will strongly depend on your location. Shipping costs also strongly depend on the shipping method you prefer.
Of course, I will only charge the real costs, I won't charge anything for packing materials and effort. I prefer to use Deutsche Post/DHL, but you can decide which shipper and which shipping method I should use. Very secure packing by me is obvious.

As payment method I prefer PayPal for friends and family, so no extra fees will be added. Other payment methods on request. Of course personal collection of modules in Cologne (Germany) and payment in cash is also possible.

Kind Regards
Phil

Hello dear diyaudio friends

I'm clearing out my stock of NOS components and parts, as I have too much stuff and too less space.

Up for sale is my stock of different NOS STKxxxxx hybrid amplifier modules. These modules are all NOS and guaranteed to be original.
I bought them a long time ago. They were always stored in anti static bags in a dry, temperature stable environment.

Price for all modules together: 250€



I’m also willing to trade for one or more of the following items:
(Of course, I will pay the difference in value)

Manufacturer sealed bags of:
2SJ74-BL
2SK170-GR
2SJ74-GR
2SK370-BL
And maybe other rare signal JFETS or dual JFETS

BurrBrown PCM1704-K DAC chips

Analog Devices MAT02 and MAT03 dual monolithic transistors

Analog Devices / PMI BUF03 Buffer ICs

2 x Starkrimson® Ultra Amp Module

XRK Audio RTR TPA3255 Reference Class D amplifier

Please also take a look at my other offers in the Swap Meet


Here are some different shipping rates:
They may differ a little from country to country, for a exact quote for your country please ask.
Of course, I will charge only the prices I will have to pay)

(Prices for bubble wrap envelopes are valid for most countries worldwide, DHL package prices are a bit cheaper within Europe)

Bubble wrap envelope up to 500 grams (Deutsche Post):
Without insurance and tracking: 3.70 Euro
With insurance up to 30 Euro and tracking: 7.20 Euro

Bubble wrap envelope up to 1KG (Deutsche Post):
Without insurance and tracking (Deutsche Post): 7 Euro
With insurance up to 30 Euro and tracking: 10.50 Euro

Small DHL package worldwide (up to 2KG):
Without insurance and tracking: 10.99 Euro
With insurance up to 50 Euro and tracking: 14.99 Euro

Small DHL package within Europe (up to 2KG):
Without insurance and tracking: 5.99 Euro
With insurance up to 50 Euro and tracking: 8.49 Euro

Shipping within Germany will be cheaper, please ask.

I will ship anywhere in the world. Shipping costs strongly depend on the number of capacitors you are going to buy and which shipping method you prefer. Of course, I will only charge the real costs, I won't charge anything for packing materials and effort. I prefer to use Deutsche Post/DHL, but you can decide which shipper and which shipping method (letter, registered letter, small package, normal package, insurance, tracking) I should use.

As payment method I prefer PayPal for friends and family, so no extra fees will be added. Of course personal collection of capacitors in Cologne and payment in cash is also possible.

Kind Regards

Phil

Hello dear diyaudio friends

I'm clearing out my stock of NOS components and parts, as I have too much stuff and too less space.

Up for sale is my stock of different NOS amplifier IC's. These IC's are all NOS and guaranteed to be original.
I bought them a long time ago. They were always stored in anti static bags in a dry, temperature stable environment.

Price for all chips together: 150€




Price for all chips together: 150€

I’m also willing to trade for one or more of the following items:
(Of course, I will pay the difference in value)

Manufacturer sealed bags of:
2SJ74-BL
2SK170-GR
2SJ74-GR
2SK370-BL
And maybe other rare signal JFETS or dual JFETS

BurrBrown PCM1704-K DAC chips

Analog Devices MAT02 and MAT03 dual monolithic transistors

Analog Devices / PMI BUF03 Buffer ICs

2 x Starkrimson® Ultra Amp Module

XRK Audio RTR TPA3255 Reference Class D amplifier

Please also take a look at my other offers in the Swap Meet


Here are some different shipping rates:
They may differ a little from country to country, for a exact quote for your country please ask.
Of course, I will charge only the prices I will have to pay)

(Prices for bubble wrap envelopes are valid for most countries worldwide, DHL package prices are a bit cheaper within Europe)

Bubble wrap envelope up to 500 grams (Deutsche Post):
Without insurance and tracking: 3.70 Euro
With insurance up to 30 Euro and tracking: 7.20 Euro

Bubble wrap envelope up to 1KG (Deutsche Post):
Without insurance and tracking (Deutsche Post): 7 Euro
With insurance up to 30 Euro and tracking: 10.50 Euro

Small DHL package worldwide (up to 2KG):
Without insurance and tracking: 10.99 Euro
With insurance up to 50 Euro and tracking: 14.99 Euro

Small DHL package within Europe (up to 2KG):
Without insurance and tracking: 5.99 Euro
With insurance up to 50 Euro and tracking: 8.49 Euro

Shipping within Germany will be cheaper, please ask.


I will ship anywhere in the world. Shipping costs strongly depend on the number of capacitors you are going to buy and which shipping method you prefer. Of course, I will only charge the real costs, I won't charge anything for packing materials and effort. I prefer to use Deutsche Post/DHL, but you can decide which shipper and which shipping method (letter, registered letter, small package, normal package, insurance, tracking) I should use.

As payment method I prefer PayPal for friends and family, so no extra fees will be added. Of course personal collection of capacitors in Cologne and payment in cash is also possible.

Kind Regards

Phil

I have a DCA75, but with more current and higher measuring voltage the device reaches its limits. What alternatives are there to be able to measure larger transistors? E.g. Ib is stated between 1-8ma and up to 60V in the data sheets, but the DCA75 can only measure uA and up to 12V.

Hello dear diyaudio friends

For sale are two brand new Mirand TSSA V4 amp modules.

I want 500 Euro for both modules together.


I’m also willing to trade for one or more of the following items:
(Of course, I will pay difference in value)

Manufacturer sealed bags of:
2SJ74-BL
2SK170-GR
2SJ74-GR
2SK370-BL
And maybe other rare signal JFETS or dual JFETS

BurrBrown PCM1704-K DAC chips

Analog Devices MAT02 and MAT03 dual monolithic transistors

2 x Starkrimson® Ultra Amp Module

XRK Audio RTR TPA3255 Reference Class D amplifier

Please also take a look at my other offers in the Swap Meet


Here are some different shipping rates:
They may differ a little from country to country, for a exact quote for your country please ask.
Of course, I will charge only the prices I will have to pay)

Small DHL package worldwide (up to 2KG):
Without insurance and tracking: 10.99 Euro
With insurance up to 50 Euro and tracking: 14.99 Euro
With insurance up to 500 Euro and tracking: 47.99 Euro (DHL insanely raised the prices, this package is also 5KG)

Small DHL package within Europe (up to 2KG):
Without insurance and tracking: 5.99 Euro
With insurance up to 50 Euro and tracking: 8.49 Euro
With insurance up to 50 Euro and tracking: 13.99 Euro

Shipping within Germany will be cheaper, please ask.

I will ship anywhere in the world. Shipping costs strongly depend on the shipping method you prefer. Of course, I will only charge the real costs, I won't charge anything for packing materials and effort. I prefer to use Deutsche Post/DHL, but you can decide which shipper and which shipping method (letter, registered letter, small package, normal package, insurance, tracking) I should use.

As payment method I prefer PayPal for friends and family, so no extra fees will be added. Of course personal collection of modules in Cologne (Germany) and payment in cash is also possible.

Kind Regards

Phil

Hello dear diyaudio friends

After a longer break from diy audio, I'm finally back in and starting with the sale of electronic parts.

Starting with the "holy grail of capacitors" the very rare Siemens Epcos MKV B25839 with 0,22uF and a rating up 700 Volts.

I bought them many years ago in original sealed bags, I have about 400 pieces of them. In the pictures you see only one opened bag.

Price 13 Euro per each capacitor. They are very rare. Only one shop on eBay sells them for more than 30 Euro per piece.

I’m also willing to trade for one or more of the following items:
(Of course, I will pay difference in value)

Manufacturer sealed bags of:
2SJ74-BL
2SK170-GR
2SJ74-GR
2SK370-BL
And maybe other rare signal JFETS or dual JFETS

BurrBrown PCM1704-K DAC chips

Analog Devices MAT02 and MAT03 dual monolithic transistors

2 x Starkrimson® Ultra Amp Module

XRK Audio RTR TPA3255 Reference Class D amplifier

Please also take a look at my other offers in the Swap Meet


Here are some different shipping rates:
They may differ a little from country to country, for a exact quote for your country please ask.
Of course, I will charge only the prices I will have to pay)

(Prices for bubble wrap envelopes are valid for most countries worldwide, DHL package prices are a bit cheaper within Europe)

One MKV capacitor has a weight of about 12 grams

Bubble wrap envelope up to 500 grams (Deutsche Post):
Without insurance and tracking: 3.70 Euro
With insurance up to 30 Euro and tracking: 7.20 Euro

Bubble wrap envelope up to 1KG (Deutsche Post):
Without insurance and tracking (Deutsche Post): 7 Euro
With insurance up to 30 Euro and tracking: 10.50 Euro

Small DHL package worldwide (up to 2KG):
Without insurance and tracking: 10.99 Euro
With insurance up to 50 Euro and tracking: 14.99 Euro

Small DHL package within Europe (up to 2KG):
Without insurance and tracking: 5.99 Euro
With insurance up to 50 Euro and tracking: 8.49 Euro

Shipping within Germany will be cheaper, please ask.

I will ship anywhere in the world. Shipping costs strongly depend on the number of capacitors you are going to buy and which shipping method you prefer. Of course, I will only charge the real costs, I won't charge anything for packing materials and effort. I prefer to use Deutsche Post/DHL, but you can decide which shipper and which shipping method (letter, registered letter, small package, normal package, insurance, tracking) I should use.

As payment method I prefer PayPal for friends and family, so no extra fees will be added. Of course personal collection of capacitors in Cologne and payment in cash is also possible.

Kind Regards

Phil

I am very new to audio analyzers and I’m wanting to get a good setup. I have a Quantasylum QA403 and did my first amp measurements a couple of days ago. I quickly learned the need for good cables and connections. I couldn’t figure out why an amp I had just rebuilt was nearing a full percent of distortion at rated output. I guess 12 foot speaker cables and a very long rca cable wasn’t a good idea. With some changes I now have it reading 0.01% at output which is better than spec.

With knowing short cables are best I ordered a pair of 3 foot BNC to rca cables and plan on using 2-3 foot speaker cables to use from the amp to the load.

I bought these 1000w resistors years ago. I was told they were non inductive, but I’m thinking that isn’t the case.



Anyone familiar with this style of resistor? Is it okay, or pretty crummy? I think they’re known as “braking” resistors. On eBay you’ll see they’re advertised as non inductive.

I want to keep my options relatively cheap. I have this old aluminum inverter case. It measures 17 inches long, 8 inches tall and 6-1/2 inches wide. One of the end caps also has a fan built into it. So hopefully it would do well at keeping the temp down




My thought was to buy ten 100w resistors like these for each channel, 20 in total. If it could handle it then later down the road I would buy more so I could switch between 8 and 4 ohm.
https://www.digikey.com/en/products/detail/ohmite/AP101%2050R%20F/13909860?utm_adgroup=General&utm_source=google&utm_medium=cpc&utm_campaign=PMax Shopping_Product_Zombie SKUs&utm_term=&utm_content=General&utm_id=go_cmp-17815035045_adg-_ad-__dev-m_ext-_prd-13909860_sig-Cj0KCQiAhomtBhDgARIsABcaYynyMTcRWOEaDbMB2LMRXNDy_YbtueiUcIMC4K64U8_8LT2Ko0_yF3MaAh2CEALw_wcB&gad_source=1&gbraid=0AAAAADrbLlgfY-1O4jlSzA_HvUlx1PUR1&gclid=Cj0KCQiAhomtBhDgARIsABcaYynyMTcRWOEaDbMB2LMRXNDy_YbtueiUcIMC4K64U8_8LT2Ko0_yF3MaAh2CEALw_wcB

Clearly they can only handle their rated power with the help of a heatsink, I’m hoping mine can handle 2000 watts of heat. The case had roughly 40 MOSFETs on it for a 2500w inverter.

Does this all seem like a good plan or will in not see any difference from my current 1000w loads? As they are decent enough???

Dan

Greetings to everybody and thank you for letting me post my rather stupid questions. Hopefully I can contribute to the forum as I learn more.

I'm currently trying to build a stereo amp using a pair of Chinese JLH 1969 kits. At this point, I've stuffed a PCB from one of the kits, but I want to be sure of my power source before learning how to adjust/test the circuit. I don't want to fry anything. Despite plowing through loads of posts from various sources and watching Youtube, I still haven't found a simple step-by-step guide to building this amp.

Does anybody have a link to a set of basic instructions on how to build a kit like mine? Are there any instructions out there on how to build a basic power supply for this amp?

Is it okay to use a "wall wart" transformer that provides 12V dc from standard US household AC? If the "wall wart" is okay (even if just for adjusting/testing), what is a typical 12V current rate - 1A? 1.5A? 2A? I'm not trying to modify the amp circuit, so whatever voltage/current gets the "standard" performance is fine.

Thanks for any help. Again, I apologize for such basic questions.

I am not sure if anyone has mentioned how they tension the diaphragm when assembling the case. What are the specs for the tension and how can it be incorporated into the case itself? How or what is holding the tension of the Kapton or mylar ribbon? Is it serviceable? Would the incorporated tension system be consistent from unit to unit after assembly?

My assumption is that all films are glued to a insert/case prior to assembly. Similar to the Infinity Emim's., can we implement a self tensioning system as part of the case or insert?

What if the casing/insert had a machined groove around the perimeter on each half using a ball end mill. If the O-ring material is .125", then mill your radiused channel .075" deep on each casing. This half circle on each casing matches the diameter of the O-ring itself. You then take the O-ring and adhere it to one half of the case/insert. During assembly one half of the O-ring is above the surface of the case, and as it mates with the other half, the diaphragm is stretched as it conforms and is driven into the other machined casing. The Durometer/Shore rating of the O-ring material, and diameter would dictate the tension created during the interference while assembling the casing halves. I have seen Mylar sheets stretched in this manner on several occasions and think it would be applicable to our needs. During the assembly process you can kiss the mylar to the O-ring and pull any sags out of the diaphragm. Then compress the shell halves together and allow the O-ring to drive the membrane into the opposing channel to stretch it around the perimeter. The Mylar/Kapton will slip as the compression occurs and maintain consistent tension. Once contact with the frame occurs on the membrane, it should keep the tension as needed.

Use rope style Buna N or silicone O-ring material to fill the casing half.


Has anyone tried this tensioning method or seen it in use for our needs? Any thoughts?



Thanks,

Mark

Hi,

I'm selling some Whammy bare PCB. Made from the gerber found years ago on the Whammy thread.



Price 18€ + shipping from France

Regards

Damien

what is 38W on SMD component with 3pin

Moving into my 3rd speaker build currently. I am trying to build a high end bookshelf. Performance should match speakers in the $1,000 to $2,000 price range. The design goal for this build is crystal clear midrange (within reason for a 2 way), and low distortion in the low end. This build will be paired with a sub, but I want the speaker to be able to perform reasonably without one. To achieve my design goals I have chosen to use a larger speaker driver, 7-8in rather than a 6in to achieve a better base response. I narrowed the choices down to two drivers. the Satori 7.5 in and the Revelator 8531g 7 in. The satori driver I know has a wonderful and rich bass, as demonstrated in some of Troels designs. The revelator woofers have a good reputation, and have also been used in many notable designs. I have not been able to find any distortion or FR measurements for these drivers (I actually found some for the revelator but none for the satori). I was wondering if anyone has either used these in 2 way designs, or has measurement for them. (It is worth noting that I also considered the SB ceramic cone drivers for this build, but some measurements from Erin's Audio Corner showed serious distortion in the bass. Its strength being the midrange was incredibly clear.)
As far as tweeter choice I am spilt between the Seas DXT, and the Satori TW29RN-B-8. I have heard that the DXT is an unbelievable tweeter, but have also been told that it is very difficult to work with integration wise. The Satori tweeter again is used in one of my favorite Troels designs. Obviously I will finalize my tweeter choice once I know what woofer I am using, but I though it worth mentioning.

Bottom line,
In the future what are the things I should be looking for in a driver when I am trying to evaluate its validity for a certain design. Suggestions on this build in particular would be greatly appreciated, but I would like to avoid writing a whole thread for each speaker build I undertake 😆.

Hi all!
I found a suitable bluetooth transmitter for my project, but it has two nuances.
I need to increase the standard volume to 100 percent. The transmitter is built on the QCC3040 chip.
I also want to remove the ability to connect a second device, leaving the connection to only one device. Is it possible to make these changes via USB?
I would be grateful for any help in this matter.

Hi all, new here. I'm trying to build an amp with PCBs purchased to make up the amp and the power supply board. An 80va dual toroidal transformer is recommended.
I've put the circuits together and have now managed to burn 2 toroidals and one other transformer too!
I'm not sure what I'm doing wrong but have posted an image of my setup here (excuse the poor quality!)
The project is a guitar amp in a wooden box. I've inserted a metal plate to have a ground point for incoming 240AC.
The transformer is mounted vertically on the back wall of the amp.
Any advice is greatly received!!

Hi everyone, I've got a pmillett HA-2 clone. Everything has been fine, but just recently after a bit of use the 6.3v appears to gives out. However the 5v for the rectifier tube is still underway. Let it sit for a bit and everything comes back just fine. And then it goes out after a while.

I'd think if a winding were failed it would be just completely gone, but things seem to be intermittent which is odd. Any thoughts?

Hi, I’m the proud owner of a Nakamichi IA-2 integrated amplifier, and I’d like to program my universal remote to control it. Can anyone help me do this—I can’t seem to find the right codes anywhere.

Thanks!

Complete working MC phono preamp. Circuit loosely based on Hagtech IC design. Passive RIAA. AD797an and AD712jn ICs. VRDN style plus and minus DC voltage regulators. Outboard power supply. 3 stages. 1st and second stages set at 30db gain, 3rd stage adjustable from 14db to unity gain. High quality parts. 100% operational and no problems. Input set at 47K.

Asking $250.00 obo plus shipping. Prefer CONUS shipment.

.

Hello.
I have too much things over here and I need more time and more room to test another projects.

For sale:

1.- a pair of Aleph J Oficial DIY Audio boards and matched components fully built and tested. 75€ for the pair

2.- a pair of F5 Oficial DIY Audio boards and matched components fully built and tested. 75€ for the pair

ONLY BOARDS FULLY POPULATED AND IN PERFECT WORKING CONDITION, no heatsink, chassis not any other items.
Prices + PP fees + Shipping

Hi guys. I suggest an amplifier with 0% distortion. It remains only to make the board correctly.

Ok maybe it's not particularly class D related, but how to add gain adjustment to a class D power amp.

Purifi and (Hypex) Nilai have implemented it in their designs so you can switch between different gain values to properly match pre- and power amp.
And what kind of solutions are possible and with what influence on the audio signal? I mean is there a better and worse way to design?

Thanks in advance

Hi all,

Recently picked up a cheap driver that I wanted to play with and figured I could use a new sub in my office. The GRS 12SW-4HE is $60 shipped with a little tax from P.E. It's sensitivity is ok, around 84db, supposedly is capable of 20hz and has decent xmax of 12.5mm so figured it could be a fun little driver to tinker with. I modeled it a few times in WinISD and played around with bass reflex enclosure designs, simple ones, with a slot port folded inside and used Subbox.pro to do simple models to look at for size and measurements while keeping consistent net internal volume. I'm powering this with a 50 watt amp that I have laying around (an AudioSource AMP100) since its near field it doesn't need hardly any power to do its job (less than a meter from my skull). I'm using a Dayton DSP-LF as my DSP to handle crossover and PEQ. Once I learned iWoofer app, it was much easier to handle this.

Note, I'm not a woodworker or carpenter, I have a few tools from over the years. I made plenty of mistakes. Still learning!

WinISD Modeling

Here's my WinISD modeling. I only enabled a lowpass filter to keep it from attempting full range.

3 Cubic Foot Bass Reflex Enclosure with a 21hz Tuning Slot Port
Modeling at 3 feet and 100 watts (more than I will actually use, I will actually use 50 watts approximately)
Kept the port big enough to keep air velocity well below 18 m/s
At this close range and low power it never approaches its xmax limit, so it's good all the way to its 250 watt power handling in this regard







Modeling the Enclosure

I used Subbox.pro website to do a basic model. Since it's a bass reflex enclosure, I wanted to do a simple slot port folded inside which this modeling software does an ok job of as I don't like the look of big round ports and wanted to build a folded slot port anyways for fun and to get some more experience with that.

The net internal volume is being kept at 3 cubic feet
The slot port is tuned to 21hz and is 1.36" x 14.74" x 35.23" as modeled (in reality I rounded this a little for simplicity)
External cabinet dimensions are 22" x 16" x 22.63"
I allowed for up to 0.65~0.85 Ft^3 displacement for the driver and bracing components




Building It!

I needed more clamps, so used this as an opportunity to pick up more 36" and 24" clamps. I picked them up from Harbor Freight for $8~6 respectively and they work like champs.

I picked up 1.25" wood screws (100x) & some larger black screws for mounting the driver
I picked up some Titebond Original Wood Glue (16oz)
I picked up some Wood Filler paste to fill in holes and gaps

I picked up a single sheet of Birch plywood from Lowes (lighter weight was my primary reason), it was kind of pricey at $80

I picked up some Minwax Dark Walnut stain ($7) & some Matte Clear Coat ($6)

I picked up some heavy binding posts that just get mounted via drilling a hole and pushing them in ($10)

Tools I already had: Jigsaw, Orbital Sander, Drills & bits (including a counter sink bit), some clamps, hot glue gun & glue sticks, caulk

I had some spade terminals and speaker wire already

Phew, ok, here's some photos of the building process as I photo documented most of the big steps along the way. I'm in Florida and this got interrupted with Hurricane Ian so I was outside, inside, and then got called into the hospital for disaster potential, and then got back to it to finish up. So it's messy. Sorry. But hey, it shows that you can do it without a garage and without a shop, etc.

Cutting the birch ply with a jigsaw

I marked my driver circle cutout with a jig I had for my dremel, could have just used a screw and string and did the same thing though. It doesn't have to be a perfect circle.



Cut my janky circle, just enough to drop in the driver. Test fitted and left it at that. I drilled into the inside circle to make a hole and then the jigsaw went in and I just slow cut around the edge. Pretty simple, but not super precise or pretty.



For joining pieces, I opted to use a counter-sink bit and drop in wood machine screws in addition to the wood glue. I wanted to do this because a lot of my jigsaw cuts were not perfect. I wish I had a table saw or track saw, but I didn't for this project, so messy edges were a reality. I just sanded things and made them fit with the screws and glue. I knew I could fill in holes and gaps with wood filler paste later and sand it away.



Joining sides, clamping, and putting this huge mess on my office floor due to rain and storms here in Florida.



Ruined a blanket we were throwing away anyways...



Big helper came into the cluttered nasty office. How cluttered? Microscope, junk, drills, 3 year old, big sub box, you know how it goes...



Passing inspections...



Clamping the inner port below the driver



Dry fitting some pieces and cut a "window brace." It's not pretty. I just drilled holes and used the jigsaw to cut windows.



Dry fitting the bottom of the enclosure with the port. Preparing to put bracing in the port itself. I cut small pieces and glued them along the middle of the port on both tracks.



You can see some bracing in the port here (lower left) and just have the window brace sitting in there crooked just to see how it will sit and fit and all that...



More storms, back into the house to clamp some more with some help...



Drilled 1/4th inch holes into the back of the box and then inserted the heavy binding posts and pounded them in with a weight...



On the inside, I attached spades and wire to the inner binding post terminals and then hot glued all of it so that it wouldn't rattle or more at all. It looks like a hot mess and is. But it stays in place. I hot glued the wire along the edges and through the window brace to the driver location and left only some of it free hanging to attach to avoid any rattling wire dangling.



Here you can see the wire snaking through and glued to it, that's the top of the enclosure and above the port. Also a look at the slot port itself before I close up the box.



A final peak inside before the top goes on to seal the entire box other than the port and the driver location.



Continued....

Very best,

For sale is my really clean example of the legendary EMT 930st professional studio turntable.

Plenty of info out there on this classic, vintage idler.

TT serial number 41079 – so mid-late 70’s manufacture I’d reckon. This unit was fully refurbished by Herr Hans Fabritius – a former EMT employee who was highly regarded in EMT refurbs and parts until retiring recently (see https://www.fabtech.de/en_index.html ).

This unit comes with:

• new idler and spare tyre, 45 rpm adapter, anti-skate weight and string, and some oil;
• EMT 929 tonearm;
• EMT 155st variable eq phono stage (serial # 41470);
• EMT TSD15 SFL cartridge (EMT refurbed and sealed);
• 3 metre audio cable - 8 pole (from 155st) to RCAs (line level);
• manual;
• UK power cable; and
• custom Russ Collinson plinth made from bamboo and panzerholz. Pre-drilled for your feet of choice.

Played with my EMT OFD65 and all works as it should – quite lovely in fact!

I’m based in Dublin and cash-on-collection most welcome, but happy to ship (preferably UK/EU) at buyer’s expense and risk.

Asking €9000 via bank transfer.

Cheers
Adrian

I'm selling Supra Ply 3.4/S speaker cable by the meter. Condition is brand new.
Asking price is $5/m + shipping.

Hi, I am an Elvis tribute. I play to backing tracks. My shows so far have been for 100 people and the venue was approx 1000 sqft.

I am looking at playing to approx 350, inside, and the venue is 4500 sqft.

I have 2 x Alto Ts415's. Probably myself and 2 backing singers plus the backing tracks.

Is this enough? or will I need more?

Many thanks

I noticed something for the first time using PSUD with a voltage doubler, the ripple sine wave is flatter on the positive swing and pointier at the bottom. Why is this?

Hi all,
It is great to be here.
I am John and I live in Chichester in the UK.
I grew up loving the sound of valve amplifiers, as back then there were valve equipment than transistors. That soon changed for the worse and I ended up designing digital chips for high definition TV.
After getting made redundant more times than I care to remember I decided to start my own company up making transformers and chokes for HiFi and guitar valve/tube based amplifiers https://primarywindings.com.
We have just started another site with our brand new Mullard 33 stereo https://classic-sounds.co.uk in ready built or kit form.

I love my job, it is hard work but so rewarding when a customer feeds back that they are so happy with their output transformers etc.
Please take a look at the link above, maybe there is something you fancy, or maybe you need a bespoke device designed.
Anyway, that is enough of the plug.

Best,
John

So I've been working on a custom amplifier, and it's mostly built and sounds good. As an afterthought, I measured the voltage between the the live and neutral, and it measured 230V as expected here in Spain. When I measured the live to the ground though, expecting 230V, it measured 135V. I measured neutral to ground, and it also measured 135V. I know for sure there is a ground wire in all the plugs because I paid someone to do a full rewrite of my apartment three years ago.

I used a plug tester, and it showed "open ground". I contacted an electrician here, assuming it was a problem, and they said that it's quite common in Spain for ground to not actually be connected to anything, since in older apartments there literally is no building ground to tie into. And of course, not being on the first floor, there is no where to drive a stake to put one in.

I thought he was full of crap, so I contacted another British electrician here in Spain, and he confirmed it. He said the grounds are still all connected together and they provide an escape path for a stray current, which the residual current device in the consumer panel would then detect and trip the breaker. I have tested the RCD using a downstream RCD tester, and it works properly, so I think he is right in that there is still protection. I believe in North America this is valid as well using a GFCI when there is no ground available. But it boggles my mind though that there is a ground wire that isn't actually at 0V.

Anyways, it is what it is, but I'm just curious how that affects an amplifier? I'm guessing the chassis isn't really earthed then, and it's not really providing any EMI suppression? I was laughing at my ground lift circuit, since my whole apartment is essentially a ground lift circuit.

Any thoughts? Thanks.

I need to test out a feedback cancellation algorithm for a hearing aid firmware. When it comes to generating feedback for testing hearing aids, I think there is no other option but putting the hearing aid inside a real ear. So I am looking for an alternative, but I cannot find something that seems right and within my budget. I can find cheap silicone ears and microphones, but I cannot find any setups that combine the two. A kemar head and torso simulator is probably the industrial grade version of what I am looking for, but it is too expensive and I probably don't need all it's features for my current requirements. I need a fake ear that (adequately enough) simulates putting a hearing aid on a real ear, with microphone attached to it that will allow me to get the audio reading, and within a reasonable budget.
Does anybody have any suggestions on what I can use? Or any suggestions or personal experiences to share, on making a custom setup?

I have no real interest in tubes, but have some I would like tested, so I bought a utracer.
I just finished calibration of utracer today, with succes.
There is not much info for beginners on how to wire up a tube socket to utracer, any help is appreciated.
Dont want to destroy utracer or tubes in the process.
My first to test would be the ecc family, dual triodes.

Friends! help connect the amplifier module on MA12070p (1.6v black board from Aliexpress, digital i2s input) with DSP adau1701

When connecting MCLK (amplifier-dsp) it gives an error when loading the firmware into the eprom. Following the advice, I connected MCLK to BCLK DSP. I set the settings (I hope that they are correct) in SigmaStudio as a result the sound from high volume speakers is distorted and it is not regulated by the volume level from adau1701 (from SigmaStudio). I assume that the volume level can be adjusted through the ma12070p registers using mh-tiny and arduino IDE, but I have not found information on how to do this anywhere.

What am I doing wrong? how to achieve results?

Hi there apologies if this has been discussed but I am building a VU peak meter with a VU kit which includes a driver and 2 VUs. Works great but not sure best way to get signal to meters. Atm ive got input from tape rec rca out on amp but the signal is low. What is the best way to connect to get the VU levels to correspond with volume control? Thanks

Hi All

After making a set of simple bookshelf speakers for my desk last Summer, I've decided that I definitely want to continue this.
So for my next project, I've more or less landed on the Mini Statements by Jim Holtz (however, I'm always open for other suggestions in the same price- and size range). As I want to minimize clutter in my living room, however, I want to make these into some active speakers. While this is not much of a challenge, I would also like to integrate them into my existing multiroom setup using airplay 2, but so that they show up as a single speaker.

Now the questions are:

• How do I do this without having to put a wire in between both speakers and without sacrificing on quality too much (a little bit is ok, I acknowledge that wireless connections are inferior to wired ones 😉)?
• What kind of hardware do I need for airplay 2?
• Do you guys have any recommendations on amps?
• I guess I need some additional power electronics to power airplay receivers?
• While I'm at it, would it be beneficial to just forego the crossovers and add a DSP to ?one?/?both? of the speakers?
• Anything else I should consider when modifying the mini statements to put all of this additional hardware into them (my best guess is to increase the cabinet size by the volume of the added electronics)?

I've attached a rough sketch of what I'm imagining below.


Do you guys think that this is a thing that is worth doing in general? Thanks in advance for your feedback and tips 🙂

I am trying to identify which one are bridge rectifiers on this bord if someone can help me.. I am trying to do the same modification that is done in following post.

https://www.usaudiomart.com/details/649982032-parasound-hca-1206-amplifier-fully-upgraded/

Has anyone noticed, that you cannot get schematics let alone buy parts i.e. toroidal transformers etc for Dayton products. PE is a joke. Talk about shooting your self in the foot. Dayton products that you cannot buy parts for is ridiculous. But I guess that's how there making there millions, on junk you cannot repair. Just throw it away and buy more junk from PE. What a racket! 👎😡

Hello!

I have (2) Pass ACA Mini PCB boards for sale, they are inspired by MJohnson’s modifications and Prasi’s Gerber intellect.

Each board is $15 shipped in the continental US.







Silkscreen was accidentally printed with IRF530/9530 but actual parts recommended for QR3/QL3 and QR4/QL4 are 520/9520 combo.

Actual PCB’s are black in color with white silkscreen.

Thanks,
Anand.

So I noticed my output tubes sounded better in the shade, and when sun shone on the plates, the tone suffered.

Has anyone got any ideas on UV protection, (while maintaining the beautiful appearance of the output tube)

😉

I've often pondered the concept of vinyl records being associated with analog nostalgia. However, when considering the purchase of vinyl editions for contemporary movies, it's interesting to note that these recordings are digitally produced before being transferred to analog vinyl. Does this mean we are truly experiencing analog nostalgia in such cases?

Hi,

I apologize in advance for my very novice knowledge of electrical engineering. I'm an audio and music enthusiasts / amateur musician who works as a mechanical designer in robotics. I have some exposure through my team and hobby to have just enough knowledge, or lack thereof, to be dangerous!

I have a pair of Carvin AG100D combo amplifiers which I use for my electric double bass along with my acoustic with a piezo pickup. I'm fond of this combo, as are a few other bass players, as it's a great sounding full range cab and fairly light. The amplifier section, however, isn't all it could be. Many use the cab only and power it with the new wave of compact class D bass head units. The nominal impedance of the cab is 8ohms. They are wired from the factory to daisy chain in series as the TDA7294 based amplifier section isn't stable enough to run sustained at any volume to support a 4 ohm load. It also is noisy and lacks headroom which becomes obvious at moderate volumes. Testing with Markbass Blackline 250 (150w rms @ 8ohms) was noticably less congested sounding at higher volumes in a not so blind a/b.

I was interested in seeing if I could leverage the +- 50v (data sheet for the chip says 40, Carvin schematic says 50, need to measure) power supply and the preamp stage with a more robust class D solution. My goal would be to ultimately fit both combos with a new amplifier setup as I leave one at home and one in the practice space, but for starters, just doing one would be fine. I will likely mess this up a bunch, so protecting the drivers especially is important. I also work for a startup, so I'm more financially constrained than I'd like to be. So with the odds being I might blow up a newly purchased amplifier board, cost is a factor.

It would seem that the LJM L12, L15, L25 or L50 might be good fits. The cabs power handling is rated at 300w, and others have reported good results using more robust amps, but given the propensity for staggeringly inaccurate power ratings and the seemingly endless appitite of musicians to believe them, it's hard to know if a real 300w rms into 8 ohm amplifier wouldn't destroy this thing.

I've attached the schematic of the Carvin's amplifier section. BTW, I do really like Carvin stuff, so this isn't my attempt to besmirch this amplifier, I'm very, very fond of it. It's great for playing in a jazz combo and even works well for electric guitar with a modeling preamp in front of it.

Thank you in advance for what is always thoughful and detailed advice.

I have four 18" subs drivers that have been ridden hard and put away wet for at least 30 years.
None of the coils are rubbing, and the suspensions are OK.
They are 8 ohm drivers, and Impedance reads 5.5 ohm on two of them, 5.8 and 5.9 ohm on the other two.

I'm wondering if they might just be a little "worn out," and so worth re-coning. I will certainly re-cone the two that have higher impedance as that could be compromised voice coils, but is it usually a good idea to just re-cone ANY sub driver that's seen this much use?

I got a Sumiko Golden Pearl cart which I bought some 10 years ago. Put it to good use, stylus is well worn, you will want to install a new stylus. No headshell, the headshell in picture is not included. These are going for $120 new price, with new stylus as $70. Asking $25 shipped, payment via paypal f&f.

At some point the "golden" from the front of the cartridge came off, this is a Golden Pearl cart.

As per the title. Brand new in box. Box opened to visually inspect the driver, pics to follow. Price is £200 including shipping within the UK.

For sale is a pair of B&C 21SW115-8 drivers. I recently bought these second hand to use for a project but have decided to go another way. Drivers in fully working condition (tested free air). Asking £600 + postage to UK. Pics available if needed. Thanks, Liam

Driver has been mounted and used in a prototype speaker, then returned to box. In excellent condition and only a few months old. Price is £80 including UK shipping.

Repairing super old bass guitar combo power amp... One resistor is burned and I can not make out its value. Measuring with ohm meter gives 1.223K ohm. I have quickly drawn schematics so hopefully someone can help as I am only hobbyist... Resistor in question is marked RX. Thanks

I have got parcel from UTSource today. What I can say only fakes!!!

Kontact via US, ordered via HK shipped from China !!!!!

Tandem regulators are a special class of two-quadrant regulators, in which the series and shunt members do not simply work side-by-side, but cooperate in an active, synergetic manner to sublimate the performances.
I have given details about the principles here (many other topologies are possible, but for the amplifier I will concentrate on a particular one):



These circuits not only work superbly as normal regulators, but thanks to their stiff, accurate output and their source/sink ability, they also do wonders in virtual ground generation

This begs the question: could they work as an output stage?

The answer is yes, and they have exceptional open-loop properties: milliohm output impedance, 0.01% linearity, >>10MHz small signal bandwidth, a fixed, stable and deterministic quiescent current, a <10mV I/O offset, etc.

They look like the dream OP stage, so what's not to love about them?
A few things, unfortunately: there is always a fly or two in any ointment, and this circuit is no exception.

The most obvious quirk is the negative input impedance: around -200 kiloohm at AF frequencies. Not a big deal you might say: connect a 180K in parallel, and the impedance becomes positive, in the megohm range.
You can even use it to change the unity gain buffer into an amplifier: connect the source through a 100K resistor, and the buffer becomes a gain of 2 amplifier; not something I recommend, though.
In addition, the negative impedance is dependent on the Hfe of the input transistor, and since it has a finite Ft, the Hfe and negative resistance will decrease with frequency, requiring additional measures.

The topology also has a more subtle, but annoying feature: a right half-plane zero.
If you look just at Q1, Q5, Q6, ignoring the rest of the circuit, you see an inverting amplifier followed by a common collector buffer, but the whole circuit is in fact a buffer: it does not invert.
This means that for a positive step at the input, the circuit will first try to behave as an inverter, until the ring of the other transistors retakes the control.

Another, more down to earth peculiarity is the difficulty to simulate it reliably: the circuit relies on NFB for DC stability, and positive FB for error correction. The EC (it is a true one, not some NFB in disguise) eliminates all the first-order imperfections.
The rest is a mix of higher order effects, some of which are not well covered in spice simulators and models, which concentrate on the most common effects seen in "ordinary", more conventional circuits.
This means that the sims tend to deviate significantly from the reality: the results are no better or worse, they are simply different, inaccurate.
That is certainly not a valid reason to discard an effective, valuable topology, but it requires more physical verifications.
Manufacturers certainly have better tools at their disposal, like Mextram, and the equivalent of LTspice used internally by ADI is certainly more sophisticated than the public version, but we have to make do with what we have.

Note that this amplifier is just a proof of concept, not a fully-fledged project like the Circlophone, the Old-Fashioned, etc. These projects have been thoroughly studied and designed to be tolerant and almost fool-proof.
This is not the case with this amplifier: you can certainly listen to music through it, but to make it into a serious project would require some homework.

The amplifier can operate in open or closed loop. This is the THD in open-loop mode: 0.04%:



The physical prototype does a little better, 0.03%. The linearity is strongly dependent on the "scaled" matching, and the matching of D1 to Q4 (I have used a diode because using a power transistor to work as a diode looks excessively luxurious).
Various resistors fine-tune the correction: R11, R12 and R14 which forces a positive impedance for the opamp output. As opamp, I have successfully tested NE5534, LT1028 and HA7 2505.
When the GNFB is in service, the THD becomes unmeasurable with my ST1700: it is probably of the order of the ppm, or lower.

Here is the impedance, also open-loop:



The real circuit is slightly worse, at ~10milliohm.

This is the actual prototype:




Here are some pics of the prototype:







And finally, the squarewave response showing the effect of RHP zero on the rising edge




The Tandem stage is very useful building block is you are prepared to develop an amplifier around it.


Here is a description of the circuit:
For simplicity, it uses an opamp for the front-end. This limits the output power to ~10W/8ohm.
Q5 and Q2 do the buffering work, and Q4 senses the current through Q2, scales it and applies it to Q5. Since the emitters of Q2 and Q5 follow an analogue I/V relationship, the arrangement eliminates the exponential curvature of the characteristic, linearising the doublet; in theory at least: Q2 and Q5 need to have an intersex, scaled matching. A tall order, with different technologies, junction areas electrons holes mobility, etc.
To fit the curves more closely, corrections are added.
The components selected for the prototype were mainly chosen according to my stock. I have gone overboard with the transistors: the 2N6702 has a Ft of 200Mhz, practically a VHF PA.... The D45H11 is a bit more reasonable at 50MHz, but the BC638 and BD135 from TFK are in the 200~300MHz region. That's asking for trouble, and trouble I had: it is the reason for the hefty ferrite bead.
The first prototype on a breadboard used more sensible BD203/4, had no stability issues and still performed quite well.
The capacitor across the BYV71 might look strange: it is a fast diode, and normally the forward recovery characteristic is excellent, yet it was insufficient in this case, because the circuit pushes some components into their limits

Erin did another shootout ... at 16:04 he shows the quite promising isobars of the MoFi 8 which has a coax driver similar to the SB 8 inch MW19 Satori :

Login to view embedded media
Question is if the SB coax can match the performance or do even better?

So I thought whoever plans to use this new coax in the nearer future - here is your challenge to shine 🙂

And we have the old question asking us can such a modern 2way coax speaker compete against 3way designs?

The simplicity , elegance and stability (no broken electronics) plus low price are strong factors when planning on a new speaker with elevated budget!

Plus the real looks!

regards , me myself & I 🙂

Hello all
I'm new here, this is my first post.
I'm French so I'll be extra careful in my description as English is not always so easy for me.

I have an accuphase E203 that's behaving really strange.
One side is silent in stereo mode, no matter what input I use, while both speaker produce sound in mono mode.
This tells me the output amp is working properly (which is really good news!) but something is lost somewhere in the preamp section.
Every input has the same problem, both A and B speakers, so maybe the problem occurs where every input are mixed together but this is just a wild guess...
Could somebody please help figure out where to look first?
Cheers
François

Teated on a Hickok TV7 were 50 is low.
98/92 date code F38
98/90 G8A
75$ and shipping
thanks Rick

Scheming a little F5 build in this chassis as pictured.... while I think I will technicaly/literally be able to fit everyhing, any notable issues with such a snug fit?

Trafo is AS3218 for reference, shielded Antek.


Thank you

If someone had an original pcb for sale from the DiyAudio store, I'd take...

Thank You!

Hi, this is the tweeter of my Sonus Faber Grand Piano Domus speaker 👇





As far as I know the woofers of this speaker are from Seas, but I'm not sure if the tweeter is from the same manufacturer.

Does anybody know this information?

Thanks.

Greetings Friends. I'd like to add Moving Coil capability to my next Phono Preamp and have a few questions about wiring. I'm following the LencoHeaven LHTR 834p build and there's very little info on the MC portion of the build. For the SUTs, I've opted for a budget set from AliExpress and described as, "1: 10 + 10 Permalloy MC phono transformer, LP vinyl MC phono step-up transformer. Suitable for 3Ω to 100Ω MC cartridges." The item I received is different from the one pictured in the listing. Here's a pic:

Login to view embedded media
As you can see, there's 2 shielded transformers and 3 pins in and out for each. The input side indicates single-ended inputs with 1 as IN and 3 as GND, while the output side seems to offer SE and balanced outputs. I'm a bit confused. If I can make this work, I'll start with an affordable MC cart like the Audio-Technica AT-OC9XEB which requires 100-ohm loading (?)
How would I wire this thang? I'd like to use both MM and MC carts with this pre, so I'll need input jacks for both styles, but what of loading MC carts? Can I wire this to do 1:10 and 1:20? Listing claims so but I can't find any documentation. I don't want to use a switch or add anything that would affect capacitance , I'd rather install as many pairs of input jacks as required and wire em all with the stipulation that only one set is used at a time. Is this the way?

thanks for taking a look.

What might cause this amp (A23+) to go staticky on the right channel after about 15-20 minute warmup?
I swapped inputs and it stayed on the right channel, there were no previous power spikes/issues (Furman power surge/conditioner)

No protection circuit tripped just gradually built static on the right channel until it was as louder than the input music playing.

This was repeatable (let it cool and it started out fine until it warmed up) three times before deciding there was definitely a problem and took it out of service.

Lastly what might cause the problem to mysteriously disappear (all conditions same)?

Thanks, Bob

I don't know why everything can be easily solved on the internet. But for me, it's not like this. Someone buys online an luxman amplifier from Japan , when receive amp .....it doesn't have a fuse. After installing the fuse, the amp has problem. ! Let's go see what the problem is?
mq-80 has 2 of 6336 in output . The current of 6336 increases and the amp turns off in 1 or 2 min .It seems that they tried to fix the problem, but they didn't succeed, and the is amp sold as it is.

pot 30 k + 30k is dc balance .

Dear all,
a friend of mine bought a closed hifi shop in my town and, in the leftovers, he found this board which should belong to a Mark Levinson device, probably a preamp.
I see some similarities with the ML38(s) but I am definitely not sure. Is there anybody who can help me identifying it?
I would also be happy to understand if it can be reused in any way

Thank you in advance
Gaetano

Just saw this at futureaudiophile.

I have Just discovered that the Fountek fe85 appears to have been discontinued which scuppers my plan to make an isetta for my kitchen. Does anyone know of a design using a alternative full range driver which could stand in for the fe85?
I am also open to other designs but the isetta seemed to be perfect with solid bass and not too large as it will be sitting in my bay window. I would really like to use the tangband sub for this as it appears to be universally liked for this application.

I just had the experience of having my Clarion APX amp go silent after tending to some dirty switches.

After an extensive investigation; signal through crossover, power supplies, lifting pins, checking transistors, I rolled the dice and hacked in a jumper to the (U5) 6 pin, 4N25 opto-coupler, and it worked to allow the amp to function again(!?)

So while I am pleased that things appear to be better, I can only wonder what purpose that portion of the amp serves?

The design is very elegant and not being an esoteric type, I can imagine it’s there to protect something or serve a durability function. It was not on any of my various Clarion APX schematics I have.

Does anyone know what that part does?

Thanks.

Happy New Year, one and all....

My project for a 6AS7 PP stereo amplifier is nearing a reality, however when considering various design options I have a dilemma: What type of circuit should I use as a phase splitter? I've read various pros and cons about several types and I must admit, I'm none the wiser....

The design parameters are:

• I want to use a single 6N1P double triode to be phase splitter/driver for the PP 6AS7 power stage;
• the design will use a single positive B+ supply of between 250v and 290vdc, so no negative supply available;
• each triode in the 6AS7 will be Cathode biased using a 1k2 resistor and 100uF electrolytic, hopefully to achieve a little over 80mA plate current per triode;
• some negative feedback would be ideal;
• I understand that 6AS7 needs a wide voltage driver swing to get a useful power output (aim is for ~12w per channel);
• the input pre-amp would be one side of a 6SL7;
• the usage is for hi-fi so an option with low inherent distortion is required.

The overall design is 1-off 6SL7 plus 2-off 6N1P plus 2-off 6AS7. DC supply will be solid state rectified. This is for an existing chassis that I want to re-purpose using the valves stated.

Constructive comments sought from you wonderful people out there....

Hello there!

I have two goals:

• Get a capacitance multiplier for a chip amp (TDA7377 / STA540)
• Learn how to make a PCB with Kicad

Other than any feedback you have I am wondering:

• Maybe more than one output transistor is overkill but I'd like to keep at least two to have them run cool. Is it OK?
• I have a small dual-40mh coil. Is it useful to make a low-pass before the BD139 base with it? BTW, I joined pins to make a single coil and measured 120mH. Wondering if that's useful.

This is the circuit I get and the simulation with a 8-ohm load. I didn't set the ESR of the capacitors. I cannot measure it right now.

Hi guys:

Care to share any good kits you have completed/ modded from Ali express/ ebay etc?

Long long shot but if someone has a pair for sale, please let me know!

So back in 2016 I build myself an amplifier using an SMPS500R and a pair of L-15D-PRO (IRS2092) boards. While I'm not really dissatisfied with the amp in any way apart from maybe some hiss from the speakers when I have my ears a few decimeters from them, but I am still curious if I could upgrade it bit.

So the weak part is of course the amp boards themselves, so I was wondering what I could use instead of those boards with my SMPS500R? It's a 500w (650w peak) +-45V dual voltage power supply. Not sure exactly what the "dual voltage" actually means since I just bought the stuff after reading about it here and on some other places, but it have three outputs from the power supply to the boards, plus, minus and ground , and with my limited experience I've really never seen this apart from on this boards.
So my question is if it's possible to use this power supply with other boards like some of the modern TPA3255 boards, or am I limited to some obscure dual voltage boards?


Posting some images on my amp for attention as well 😉 Build the case out of an old computer case and some finer wooden boards. Still quite happy with the look and size of it, though the on/off switch in the front doesn't work (it physically doesn't switch as it should, not sure why) and the LED in the front doesn't actually light up (photoshop baby!) even though I've connected it to the aux on the power supply. Ah well, it does the job!

Hi all,

Thought that I would show off my new amps that I have been enjoying the past few days.

These amps are results of a collaboration between Asnain Kolarkar, my close friend , and the two famous gurus , who need no introduction.

Asnain is here in India and is an expert in transformer design and winding, and also very good at designing circuits.
He is based in India and runs a hobbyshop , Kolarkar Audio research, to cater to his interests. He has been in touch with both Jack and Bud since the last few years , and considering his knowledge and skill levels , they have authorised him to carry on with their work and designs.

So what do I have ?

1) 6AQ5 amp
Jointly designed by Bud and Asnain , this is a SE class A amp that is running the 6AQ5 power tubes in UL mode. Output is 3.25 WPC with frequency response 17Hz to 60K . No feedback has been employed, and distortion levels are vanishingly low. The driver is 6N2P , tube rectification can employ most of the octal rectifiers.

2) EL84 amp in A3 topology
SE in A3 topology is Jack Elliano's proprietary design. What I have is an EL84 amp in that configuration, punching out 10 wpc😱🤩


Both the amps are very musical , with a superb bass punch

3)
Jack Elliano's PVA

Passive voltage amplifier, that deals with impedance mismatch between the source and power amp input. It takes a low impedance input upto 600 Ohms and presents a 47k output. This has gain factor of 1:4 . It is most useful for pairing a degital source with a tube power amp.

Here are some pics.

😊

BITTE HELFEN SIE MIR! Mark Levinson ML 23.5
Mir ist echt ein Scheiße passiert!
Ich habe meinen Mark Levinson ML 23.5 vor 1,5 Jahren gewartet und wollte nun den Ruhestrom überprüfen! LEIDER ist beim Messen ein Unfall passiert!
Irgendwie habe ich mit der Messspitze des Multimeters einen Kurzschluss zwischen dem Leistungswiderstand und dem kleinen gelben 10nF Kondensator verursacht! (siehe Foto)
Er zerstörte den Sockel des gelben Kondensators und meine Messspitze komplett. Laut Messung ist der Kondensator in Ordnung. Und eine 8A-Sicherung war auch kaputt!
Nachdem ich die Platine wieder gereinigt, den Sockel des Kondensators ausgetauscht und die Sicherung ausgetauscht hatte, versuchte ich zum ersten Mal die Endstufe wieder einzuschalten!
Der Schalter beginnt zu leuchten und ich dachte, du hast Glück gehabt. LEIDER FÄNGT ES IM VORDEREN BEREICH AN ZU RAUCHEN!
Natürlich habe ich es sofort wieder ausgeschaltet.
BITTE HELFEN SIE MIR!!
Vielen Dank!
Andreas

Why 150 kOhms is better than 47 kOhms @ high quality phono preamp input
(with multilanguage subtitles !)

Login to view embedded media