Hypex 2x UcD 180 build with high performance PSU (discrete diodes, multiple power stages and PGA preamp (got from a friend). One UcD180 module has a blown cap.

You could salvage the nice all aluminum enclosure, the PSU and one Hypex module or re-build the amp. I have no time to work on this project any longer.

Asking for 130 Euros plus shipping. I can ship to anywhere in Europe (or local pickup in Austria).

​

Hi,​

around on the 2015 I was building a sound. I've downloaded the pdf and start taking all the dimensions. I don't know if was my fault or on the pdf but at the end some panels was wrong. I've said that was best to have all the plans draw in 3d.​

So I made Speakerplan Archive using the pdf of other project that I've found free online. After some years I have the idea to sell the already cut components with cnc. ​

​

Now I upgrade that site with a new site which is a Gig economy project.​

The site is www.speakerplanbuilder.com, but you can reach it from speakerplans.eu for now.​

​

Here you can buy pre-cut components or build a sound system and sell it to another.​

​

I am looking for artisans able to do this job in It,Fr,Ger,Uk and Usa. ​

Is somebody intersted?​

Let me know.​

DD​

Guys,

I'm trying to replicate the Meatgrinder sub, created by Amano here: 2x18" MEATGRINDER v2 (done!) - Speakerplans.com Forums - Page 12
I think it's based on the Martin Audio WSX.

Unfortunately there are no plans as such so trying to do this from scratch but i really don't know how it'll work out!

I just wanna find out the purpose of closing the baffles 2/3 of the way like he has? Doesn't this restrict air flow and also wouldn't the sub start pounding on the wood?

Just a thought...I mean, I know the plates are the hot parts in the tube and we have the plate dissipation. I may have a brain fart at the moment, but thinking about the workings in there...
The metal plate inside the bulb surely has no voltage drop. (ok a few uV perhaps). (I am thinking if you could measure the ends of the plate inside the vacuum tube). The voltage drop is between the plate and the cathode, that means the voltage is in the vacuum, the space between the plate and cathode. But surely vacuum cannot be heated from current running thru it?
I understand the plate gets heated by the bombardment of electrons and the current running thru it. But since there is no voltage drop on the plate, is all the heating due to bombardment of electrons?

Probably a confusing question. And I am only asking out of curiosity, I am not worried about tube design, but for some reason I want to understand this a bit better (obviously I dont understand at all).

In 2011 I made a USB to Dig Out gadget from an article in Elektor magazine of Sept of 2011. It appealed to me as I was just getting more into the possiblities of streaming and the cost was so cheap I had to give it a go. You need a cheap USB sound card which is CM108 based and they are still readily available for a few $s or £s. I hadn't used it for a couple of years having Dacs which accept either a 2.0 or 3.0 USB lead but thought I would give it another airing. It can handle up tp 96kHz which these days is no great shakes, but it is really pretty good and I thought it may appeal to others as a weekend project for fun.

The link is for the whole magazine, but the article is on pages 67 - 69.

https://worldradiohistory.com/UK/Elektor/10s/Elektor-2011-09.pdf

Hi,

I'm working on a project that would require the ability to heat water into steam via electric induction, preferably DC or via AC converter if necessary.

I'm thinking a monotube design with an induction coil surrounding it that could produce steam from 2 quarts of water in say 30 seconds or less.

Anyone here have experience with that kind of design?

Thanks,
🙂

If talking about sound, which type of amp makse most similar soft warm sound like tube amp? Which op amp is closest?

Allo USBridge Signature and Allo Shanti LPS for sale. In excellent condition. Amazing clean USB digital source.

SOLD

Amp came in with blown power supply fets and outputs .
After replacing the fets , drivers,gate resistors I checked the drive signal .

Is it normal to get a square wave on the gate and drain legs ?

Is there a schematic available for these style amps? Ive seen a few this style, and all needed service around the drive/regulation circuit, 27v Zener diodes I believe. This one amp does not however and so this is a new issue for me.

What this one has is a problem with either RCA shields or secondary ground float. The RCA shield LED blinks rapidly no matter the source (Common, grounded, floating), and the output on speaker terminals passes audio but is jumping all around. I believe this amp also blew a 12" subwoofer, and may have been sliding around in a trunk at some point.

I've cleaned and tested ALL switches, cleaned all potentiometers. Treated with Deoxit all daughter board connections. Rail voltage looks good, regulated voltage looks good. There are no damaged visual areas and all components seem tight. I pressed and tapped on a LOT of components and no change at output/RCA led.

RCA shields to non-bridging terminals is 0-ohms.
Either ^^^^ to amp ground is 1k.

Thank you in advance

Dear all,

I am new to this forum as well as audio electronics.
So I need all experts support from here to figure this out.

I started a project using tpa3116d2 Chinese board.. and supplied voltage via laptop charger 19v. but when I switched on the circuit..one channel of my speaker popping up and down repeatedly..no stopping at all..only one channel..other one and sub is ok.. so with this issue I also connect sound input through audio jack in..sound is very low and also stoping and starting continuously same as my speaker pop up.

So please support to figure this out.

Thanks,
best regards,
Indika Perera

Hello,
I plan to buy some speakers from this site.
Does anyone here has any purchase experience with the company?
I am from Malaysia

Thanks

kp93300

As the title says, wife and I are having our first baby and I am downsizing. I am located in Houston but willing to ship. We can negotiate shipping if multiple items are purchased.

I can send more pictures, just PM me or message on this thread.

Preamplifiers and Headphone Amps:

- Korg Nutube b1 Preamplifier in black Hammond Chassis with AMB Sigma o11 regulated PSU in external matching chassis - asking $500

- Korg Nutube b1 Preamplifier in silver Hifi2000 chassis and contains power filtering board inside. The power supply is a Triad SMPS wall wart - Asking $400

- Amp Camp Preamp in silver Hifi2000 chassis with Triad SMPS wall wart - Asking $400

- Whammy (Waynes Headphone Amp Must Make Yourself) in a silver Hifi2000 chassis. I added preamplifier outputs to it and a switch for either mode - Asking $350

Amplifiers:

- Amp Camp Amplifier with Diyaudio Forum modifications recommended by Tungstenaudio and Rudi Ratlos, CapMX Power Supply, 28 volt rails, and custom built chassis with 10mm silver faceplate and rack handles - Asking $700

Other:

- H2 Harmonic Generator with 12V Power supply in small, silver hammond chassis. Great way to add second harmonic distortion on a budget! - Asking $80

I'm considering building the Ampslab Osprey-BR coaxial speaker. It uses Eminence Beta 10CX with Selenium D220Ti in a 45 L vented box.

It would be for a single ended tube amp with about 7 watts in a medium room at mostly moderate to low listening levels for jazz to classical to pop.

I haven't had a coaxial speaker before. Anyone heard this setup?

Health issues have forced my wife and me to re-evaluate our collection of hobby materials. Unfortunately, DIY audio was one of the casualties. As a result, I must abandon my plans to build an F5 Turbo. I have been collecting matched semiconductors, F5T PCBs, transformers, and PS PCBs for this amp.

Furthermore, I have a bench power supply, misc chassis parts, a 400 watt dummy load, a DBT, a 2kW variac, a DMM, a Mark Jonson Quasimodo, a Mark Johnson SoftStart, and misc other PCBs, semis, resistors, and caps. Other items are included that I don't wish to take the time to inventory.

Here's the fine print:
This stuff is in the Sacramento, Calif area. It must be picked up in its entirety; there will be no cherry-picking. I will not ship. I want this stuff to go to someone who will either use it, or will give it (i.e., at NO CHARGE) to someone who will use it. Please do not put this stuff on eBay or its ilk. I anticipate having this stuff ready to be picked up on Saturday, June 25, but health issues may change this date. PM me, first on gets it that can p/u Sat 6/25

In the Alpha Nirvana thread Hugh recently posted this:

“ I continue developing the AN in fact. Maybe I will do one for commercial; but a Class A is always very challenging because of the high dissipation and low power; a combination which makes it expensive to build, as you know well. “

So my purpose in starting this thread is to encourage Hugh to implement his development ideas and release some new commercial Class A modules. I for one would buy a pair if he did.

Post your encouragement if you think Hugh should complement his range of Class AB modules with a full Class A design 😉

loudforce 2000.1 class D amplifier, the source is ok, the audio output is ok, however, the amplifier works for a minute and the sound is distorted and cuts off, no physical damage, I don't know where to start, everything looks good , Thank you

What temperature does it get on the inside of a sealed subwoofer enclosure? I just had a temperature reading of 150°F, is this normal?

I'm looking for a special style of National jumbo tube socket.

Looking at the specs for the N43 tube https://frank.pocnet.net/sheets/060/n/N43.pdf and I notice that it says you should only use the tube with "full automatic grid bias." Presumably that is because of the sensitivity of the screen makes it easy for the tube to run away. Does running it triode solve that problem? Is it still in danger of runaway with fixed bias?

I have several CD/DVD drives for computer piling up. Without knowing much of the digital domain, my question is. Can it somehow be used in some kind of setup to play cds, standalone?

I apologize if this was recently addressed here.
I plan to buy a kit from either Madisound -Sasandu or Troel- 6661

The only piece I have actually heard is the SB Acoustics Be tweeter.

-To be used in a mid sized, treated room
-Listen levels low-55-73db max
-Female vocal, Jazz mostly
-Pass Labs INT25 amp

I will be all for $5k or $7k depending on final choice.

Any suggestions?

I have a 1994 Ford F150 with a stock radio that includes a tape player that I'm currently modifying with a Bluetooth receiver. I've posted on other forums but haven't had any luck so far. I don't have a ton of experience with soldering or with modifying chips, so I don't mind anyone talking to me like I'm 5. I realize too that it could take a lot of explanation to teach someone with little knowledge, but I very much appreciate anyone taking the time. To someone of my skill, the more dumbed down the better.

The receiver comes with red and black wires for power, and then a red and a white rca cable that I've already cut off the RCA inputs to expose the wires. In my first attempt, I just spliced into the wiring for the tape player, but I could never get that working correctly.

In a perfect world, I'd find a way to toggle the "Tape Player" on and off to enter "Bluetooth Mode" (right now the tape player must be engaged to switch to tape mode, which I removed all the springs to keep it in tape mode. The problem there is that it can't switch out of tape mode. In hindsight, keeping those springs in would have been a better idea but they are all ruined now.) If that means removing most of the tape player, I don't mind that, especially since I've mostly messed that up with removing the springs. I don't know if this exists, but a toggle switch would be awesome that I could hide somewhere behind the tape door or something similar.

Here is a schematic that is close to what i have for my radio: https://www.diymobileaudio.com/attachments/ford-sound-2000_2006-sch-pdf.334305/

I am also adding photos that will hopefully help. The photo of the front of the radio isn't my radio, but that is what it looks like (mine is in better condition).

Yeah, so I'm repairing two vintage JA2501A woofers on cloth surrounds, possible shifted magnet on one woofer and weird condensation between cask basket, magnets, plates and poles on both woofers.

If I can't reuse the original dust caps what type of caps do you guys recommend? To make it look as close to original as possible?



It kinda looks like some flat felt cap or a foam - not really sure. If you push in cone a lil bit the dust cap is lifted by the air flow a bit. Its my first time seeing this type of dust cap.

Also do you guys have any link's to shops with fairly large stocks of various spider parts for woofers? I may need to search for similar spider as an original part - depends on how repairs will go, I guess.

My tech guy said that it's essential to unglue the original spider to properly demagnetize, open and clean, reglue, center magnets and properly remagnetize the magnets. Will see how that goes in a while I guess - would be cool if he doesn't damage it. The height on original spider makes me worried if I can match it with something else.


Also check out this solder job 👌

It looks massive.

$$ Sold $$

Are in good shape. Fronts are identical, terminals are a bit different. Has only been used for hifi, no PA etc.

Are in EU. Can probably ship but will be somewhat expensive.

Asking price is 200 euro for the pair.

Found! Thanks all who responded!

Like many, I am a proud papa. My DIY effort sounds great to me. Of course it does. Built, not bought. A face only a parent could love?
I get frustrated when someone posts that they like the subjective sound of their system. No matter how many times they say its subjective. No matter how hard they acknowledge it's just a personal opinion and there is no way to measure personal satisfaction etc... they too often get flamed.
Where is the measurement? Did you conduct double blind tests? You don't know anything about X, Y or Z. Yeesh! I'm just a proud papa who enjoys listening to the I stuff built. It means nothing to anyone but me.
The picture threads work well. It's ok to proudly display a picture. Just don't mention you think it sounds good and you will survive.
But the challenges are also good. Often we do something, we truly imagine it sounds better. And there is a long time between listening sessions, so who knows? Maybe we do imagine all of this.
I go to an audio show and listen to systems that cost mega$. I think it's ok. But for all that money it does it sound much better than what we build ourselves? But again... long time between listening comparisons. How do you compare? If I could compare side by side perhaps I could focus on areas of deficiency and improve.
Out of curiosity I thought it would be interesting to record my system in a given config so I could A B compare before and after changes. It actually was revealing.
It would also be interesting to compare my diy system to YouTube postings of audio show demonstrations. To eliminate the YouTube variability, I just put my own recording on YouTube and that variable is eliminated. Played back with decent studio monitor headphones you can easily hear clues to the sound signatures. No it is nothing compared to being there, but quite a bit of the sound signature is at least suggested. Box speakers sound different to horns and open baffle. Is the sound closed in or colored?
I enjoy the sound clips from Aries Cerat horn systems with triode electronics. Here is a clip of a Melody Gardot track at Munich. Login to view embedded media I like this track. Not the most audiophile tool to show transparency, but still a nice cut.
So I recorded the same track on my DIY system.
Login to view embedded media Just fun. Not a great recording. Just my Android phone with built in mics held in unsteady hands.

Hi folks,

I’m looking to buy a mono class D board about 50W undistorted into 4 Ohms. Any recommendations for a UK seller (to reduce costs of import and shipping)?

The boards could be complete, but unpopulated is OK too.

Alternatively, can anyone recommend an good open-source layout in Kicad? Or a closed source layout with the potential to be licensable?

I’m basically trying to save time by avoiding designing the amplifier board myself, so I can focus on other parts of my current project.

Hi

I've been struggling with the Alpine 3544 amplifier for some time.

It started with damaged power transistors. I was replacing them, being aware that the problem could be in the controlling degree (originals from disassembly). The upc1298V (IC 502) has failed (short circuit). I checked its surroundings and swapped upc layouts to make sure one was a problem. The diagnosis was correct and I replaced upc1298V.

Idle current set:
In the place where the old and functional upc1298V system was located, the millivoltmeter showed 0mV in TP5 and TP6 measuring points. In points TP3 and TP4 the voltage was within 3.5mV - quite correct. Soon after, the old upc1298 chip, installed in place of the previously damaged chip (IC502), also fell short.

I measured the voltages on the upc1298v systems and the measurements were consistent with the table in the service manual. The greatest deviations up to 1V.

I am puzzled by the high operating temperature of the upc control chips. Without any load and input signal, they had 55 degrees Celsius with the housing open after 2 minutes of operation. According to the table with voltage measurements (supply voltage 14.4V) on pins 9 and 10 of the PWM driver upc494 should be 267mV, and in my case it was about 5.3V on both pins (D801 and D802 removed).

Any of you repaired such an amplifier and had similar problems?

A year or so ago I purchased a deluxe 5U aluminum chassis with aluminum handles. I went to purchase another one today, but the handles look completely different. Are the cylindrical handles of a year or so ago no longer available?

Thanks,
Alan

Hello - just for fun I got a linn valhalla board. I know its probably wasnt a wise idea but i like playing. It working fine but i am going a complete service and re cap on it.

I read this post https://www.diyaudio.com/community/threads/two-speed-valhalla.97740/

and I can see somoene uses a DPDT relay to switch out the existing crystal with a higher frequency and at the same time change the phase shift cap.

Can anyone help me make this easy to understand so I can have a go doing it myself?

Thanks
Chris

Have just acquired a pair of Technics SB C-250 vintage speakers.

Generally they’re positively reviewed and I’d like to get them performing at their optimum.

2 Questions:

-What is the key quality one should seek in capacitor being used in a loudspeaker crossover (low leakage? or something else?) Please feel free to recommend a Brand and series name.

-Also, has anyone changed the caps in this particular speaker or any others and heard a clear improvement?

Actually, if the existing caps test ‘ok’ on a cheap transistor tester.. is there any benefit to changing them?

I have a non-working power amp Crown xls 1000 that is dead. Checking just past the power supply there is a shorted-out PTC thermistor reads on the face PTC-840-1011, it's a 6-ohm thermistor.
This part is no longer made but here is the replacement according to digikey... https://www.digikey.nl/nl/products/detail/amphenol-advanced-sensors/YQD120N0006/2324592

My question is and probably a dumb question, for testing purposes, can this PTC thermistor be bypassed with a resistor or with any other PTC thermistor of similar readings?

This is my first time dealing with a thermistor.

Thanks in advance

Hey.

My friend dropped off a GTO 14001 amp. It had lots of dust and some visible moisture damage inside which i cleared up. Did some reflow on solder joints that looked a bit bad but didnt find any cold solders. When amp is powered up it stays in protect but it seems to be fully working. I have correct switching on all the output fets but relays dont kick in. Only thing bothering me is that +/- voltage in the preamp/driver cards is +9.6V and - 14V. Removing driver cards and changing voltage regulator didnt change a thing. All the diodes check out fine in the psu section where secondary voltage is generated. Nothing seems to be heating up either.
Has anyone had any similar problem with this JBL series amp? Any ideas what to check next when output is switching but staying in protect?

Looking for a Tentlabs volume control - doesn’t matter if it’s new or used, as long as it’s functional.

A compatible remote (e.g. Hypex RC5) would be nice as well, but not necessary.

I am looking to connect with any DIYaudio folks anywhere near Traverse City, Michigan.

I am a few years out from retirement but I can see it from here. I am hoping to find new homes for a whole series of amps or even just to part them out so that the dumpster is not fed. I'm looking for advice. It would be great to meet a fellow enthusiast on the local side too! There seems to be no DIY audio postings from the area or even in Michigan. I'm feeling like a Dodo, soon to be extinct 😳

I’ve been building HT subs for many years and this is my favorite design. [/FONT][/COLOR]These subs have super low bass and out perform many store bought boxes.

Two long throw 8” woofers ($30 each) mounted isobaric, using small tunnel. Tunnels sound complicated, but they are pretty easy, simply use square blocks of wood with the same size hole as the woofer, laminated (glue) as needed. In this box I found that a 5” total inside depth works well. [/FONT][/COLOR]Also note; I used 1” thick wood, so bracing not needed.

The speakers are 4ohm, so ran them in series and bridged a 200 watt amp mono to drive them, an option is to run them 4ohm stereo.

As a relative noob in hifi audio, I've been playing with Hornresp to design the ideal enclosures for my pair of 2.5" Dayton Audio ND65-8 drivers. (Mainly just as an exercise in practical application to learn something about acoustics and quarter wave enclosure design)

I've tried several classic/standard/conventional models in Hornresp but the one below seems to provide the flattest response near the target tuning frequency.

What would you even call this? Mass Loaded Reverse Taper Quarter Wave Transmission Line? MLRTQWTL 😀

AFAICT it would sound good according to the model. Unless of course I'm overlooking some critical piece obvious to everyone but me.

Thoughts? What enclosure would you put these drivers in for maximum SQ when paired with a small subwoofer?

Several years ago I noticed quite a few 26, 27 & 30 enthusiasts trying to use them for their supposed tonal qualities. But the best power triodes all seemed to have MU’s of ~5. There is a fundamental problem; the overall gain is too low. The way out was a third gain stage.

I wondered if anyone had tried a Cascode front end to get the required gain, a search didn’t find much. As a first pass last year I tried simulating a Cascode with a 30 on the bottom & a common medium Mu triode on top. The Cascode triodes do not have to be the same. Just need to be able to handle the plate current.

More recently I tried using a 6J5 on top of a 27 in FlaCharlies 6N6G amp. The results looked OK so in the last few days that has been modified to drive a 6L6GC in triode or pentode mode. And a bit further, it turns out the top 6J5 triode grid can be used as a NFB point. The switches in the simulations allow the calculation of NFB, Internal Resistance, DF & Sensitivity.

The resulting amp has ~11 db NFB & DF of 3.2. And with a Volt RMS at the input 6W of audio results. Refer to simulation A. I was concerned the NFB might have a loading effect on the 27 but it turns out the load is actually relieved, refer to simulations B & C. With NFB connected the signal at the plate of the 27 doubles. And its gain is ~7.5.

Hi - I am looking for a pair of working tweeters for the earlier ( non freedom) version of the Mission 753. Anyone aware of an equivalent size, shape tweeter perhaps from other Mission speakers that would fit and perform well?. I am aware of a company that will fit a new tweeter to your housing but a previous owner seems to have glued ( very solidly) weird small silver tweeters in there that cannot easily be removed ! Any help/advice would be welcome

Fully assembled unit including original shipping carton, brand new JJ ECC82 tubes, and everything else supplied. Seen very little use.

Price 490 EUR + shipping within EU.

SOLD

Selling 4 AE Dipole15 - D8, 2 unused, 2 used for a bit. Black phase plugs. Currently $459 each on AE. Asking $1400 + shipping.

I have one of these and the reverb isn't working. I've ruled out the tank and connectors. I though it might be worth a shot to see if anybody has one that they could share with me. I've looked and haven't been able to find one. Thanks!

Hi All! First post, so I hope Ya'll will bear with me!

I was hoping someone could give a little experience/advice. I’ve been upgrading a hybrid tube headphone amp that has very limited space, mainly bypassing a few electrolytics and replacing signal path caps with higher grade ones. The headphone amp is a Schiit Mjolnir 2, a hybrid Tube/FET model with plenty of power. One of its design constraints was to use a non-regulated 6 volt supply for the tube heaters, just a simple RC network after the bridge rectifier (coming off a multi-secondary transformer). I'm considering upgrading that. and have been shopping for standalone, regulated PS circuit boards/kits/modules. As space is limited in the amp chassis, it would have to be separately enclosed in an external case. The easiest method to pipe this in would be to remove the original bridge rectifier and caps from the 6 volt heater rail of the headphone amp (thus disabling that secondary tap of the transformer) and hook up directly where the previous RC filter caps were (via an external port). But now I would be tying two separate circuit grounds together, as well as case grounds. So here are a few questions.

• Would that be SAFE,?
• Would it be stable?
• Would it be prone to noise/hum?
• Would it be advisable to tie the chassis grounds together? Or what grouding scheme would you use?
• I would be removing a load on the secondary winding from the original multi-secondary transformer. Would that effect voltage/current on the other secondaries? Would I need to compensate for those extra voltages/amperages (there are 4 secondary windings on the transformer) since a 6 volt secondary is now unused/unloaded?

The other method, which would be harder (and somewhat irreversible), would be to solder the external supply directly (via the external port) to the tube sockets, but then there is the problem of having to isolate those pins from the main circuit board. It might be able to be done by cutting traces/etc., but this is a 4 layer board and there may be connections or circuit trace routing I don’t know about. . There is no schematic. This method would also make it less easily reversed if I don’t like the results and wish to restore.

The purpose of this parallel supply isn’t per say to change unregulated tube heaters to regulated ones. That improvement would be incidental. Instead, I want to increase the max amperage of the filament circuit. Max current for a 6DJ8 tube is around 325 mA. I want to add flexibility in the type of tubes I can use with the headphone am, to be able to use 6414’s,6829's,E180cc's, or others (w/adapters),up to 500mA. So I’m trying to gain about a 1/4 Amp more heater current or so, about an amp total. Of course, I'd be glad for any benefit regulated filaments would give me, but the main purpose is tube rolling.



What do Ya’ll think? Any experience on something similar?

i would like to make a pair of focal trio11 10 inch monitors but i cant find no internal design or measurements .can someone please point me in the right direction

​

Greetings,

My AMC CVT 2100 has issues since I installed a set of Shuguang KT88.
The ZD501 and ZD502 keep shorting and blowing the mains fuse. The 270 ohms resistor is still intact.
I assume the zener diodes provide a kind of regulation but I am wondering if this feature is necessary with an ultralinear OT. I always thought that a safety resistor of 100 ohms was adequate.
The SM suggests 55mv across each 2 ohms resistor which is only 27.5 ma cathode current per tube; am I missing something?
Your help is appreciated.
Cheers

As the title suggests looking for a pair of good quality Toroidal for my J2 dual mono build. I can get Anteks AS3218 as the last resort. Shipping to Naperville, IL and do PM me with your offers.

Thanks

I've read that a hard coated anodized aluminum surface results in a non-ferrous layer that can resist up to 120V. If that is true, why use grease or pads between a chip and heatsink surface?

I am hoping to lower the cutoff freq of this crossover. is it possible to only change the large cap to do this or will it affect the entire range? Also what type of crossover is this? I meant to add that the capacitor I can read is the larger one, and its 10mF.

This project took a lot longer than I anticipated to finish but some life events got in the way. Part of the delay was fighting with finding good old stock globe tubes that didn't do weird things lol. Some of these tube weirdness issues made me question my design/other parts, but at the end of the day, the vast majority of the problems came down to wide sample variations/glitchy tubes, mainly with the 27 tubes.

Anyway, I feel like this turned out looking very cool and was fun building what I consider a modern design, using high quality parts, with these ancient globe style tubes. I used a pair of Hashimoto 5-7k UL output transformers and it sounds REALLY sweet. Loads of detail and got it tuned to have a nice balance of solid bass and a tamed top end.

It puts out just under 1.5W into 8 ohm dummy loads but I swear listening to it on my RP600M speakers, it's sounds more like 2-3W. It does need a solid 2VRMS drive but any of my modern sources can handle that. It's just enough power for me.

I did a complete build series of videos and here are the schematics and some pictures.

https://www.youtube.com/playlist?list=PLtEhh3UpOsiD-QbGfOhWdWjGsFb-4a4qL

Hi folks,

I recently got Aiyima D03 and found it has bass drop.
I have BEHRINGER UMC22 soundcard and made some voltage reducer scheme for it (according to 3kOhm XLR input of soundcard): 20kOhm resistor in series and 2.7kOhm resistor in parallel (scheme was calculated for 11.34 volt and 16W output).
When I turn on Aiyima at 0 volume all is ok, but when I increase volume by 1 step, Clip lamp in UMC22 starts to flash. I suppose voltage still too high for it and I made a mistake in resistor calculation

Could you please help me:
1) Can I measure freq response of Aiyima, using USB audio as input? I use CoolEdit / Adobe Audition to watch my results.
2) What was my mistake in scheme? Reducer should compress signal to 0.75V, here is formula:


where ZL is 3kOhm impedance of mic XLR input, Z1 is 20kOhm in series resistor, Z2 is calculated (in parallel) resistor, Vout is 0.775V, V1 is rms ampl voltage (2.82V for 1W @ 8 ohm load, 8.02V for 8W, 11.34V for 16W, 16.04 for 32W)

Have a Citation 22 where DC offset in the right channel is difficult to master. When turned on, DC speeds up to 1 volt to slowly creep down for many hours and when readjusting, i can keep it around 0. When changing the program source, it clicks into the right speaker at the same time as my DVM shows up to 1 volt and then drops slooooowly. The same result at the next switch-on and program change. Bias is OK according to the "book", so I guess the problem is on the pre-driver card, maybe the differential transistors in the right channel have given up? The question then is, which on the schedule are these transistors now? It is quite possible that there is something else that makes the DC offset go bananas when turned on, suggestions for sources of error are received with the greatest gratitude!

As titled, I'm looking to buy a well kept example of any of these four First Watt amps, listed in order of preference:

F4, F2J, F3, F1J

I'm located in upstate New York and Canada, and can receive packages in both countries without having to go through border issues. Fingers crossed and thanks everyone!

After several years building speakers I am considering building my very first “real” piece of equipment and beginner friendly preamp.
At first it will be paired with a Quad 405-2, but dow the road the power amp section could/will change all depending on needs and time.
The Nelson Pass B1 and the bottlehead Moreplay fit the bill, and would like to hear if anyone oof you had the chance to compare the 2 sound quality and build experience wise.
Thanks

Hi I'm recapping a GM2000a power supply caps, the caps are rated at 35v do I need to replace with 35v or can I assume anything above 16v will do?

Interested in applications of 6GT5 sweep tubes for PP audio amp design...
Not a whole lot out there- far as history of usage. Pic below shows what seems to be rare example-

Grommes Precision S-100​

I know Tony T has used these in SE design, and KodaBX has used them in PP...
Q's:
1. Are they a viable candidate to design low distortion good sounding 50w+50w in non parallel PP design? Or are they better suited for guitars?
2. Can anyone supply an audio amp schematic they've successfully built and recommend?
3. What kind of B+ is needed?

Thx,

Jim

I'm just wondering where the best place to put a resistor divider is in my system. My setup is that volume control is in software on my Mac Pro, which is my only source for everything. I have an amp which is 6SN7 into 2a3. The volume on that is perfect for my room - I don't need any more gain. However, I have a 2P29L line stage which improves the sound if I put in front. Problem here is far too much gain. 2P29L has a mu of 9. I really only want a 2x gain.

So looks like I could put a resistor divider in front of the 2P29L or in front of the 6SN7 or both, in fact. So where would be the most effective? The 2P29L is a better sound than the 6SN7. I may replace the 6SN7 with two 6AH4 or 1626 or something low gain like that. But for now it would be useful to put a resistor divider somewhere.

So where?

Hey all,

I'm looking for some suggestions for good tweeters similar to these. They, unfortunately, aren't shipped to my country, so I was looking for any alternatives that may actually ship to where I live (The UK). I'm looking to build a powerful directional speaker array built with 4 tweeters which would've been the aforementioned tweeters, so I was wondering if anyone had any suggestions for a machine like this?

Thanks in advance.

Hi Folks. I have a Mission PCM 7000 that I bought new in the 80s. It's been used very infrequently as I've ripped most of my CDs or buy digital downloads and stream the files to a DAC. But when I did try to use it recently, first the disc went in awkwardly and jammed the tray (maybe the CD wasn't in the tray properly), but the tray did open (pressing eject) and all that seems OK now. BUT every disc I try spins for a few seconds then stops, with the Disc and Error lights on in the panel. I took the lid off, and everything looks OK (mechanicals seem to work properly, no bulging capacitors on the boards). I also darkened the room to see if I could see any laser light when I loaded the disc, and saw nothing - but don't know exactly where to look or whether I should be able to see anything. Any advice to get this baby diagnosed or working would be much appreciated.

Hello,
I'm planning to construct a stepped attenuator for my pre-amp. I've been reading a lot about high end resistors such as Vishay’s Bulk Metal™ Z-foil etc. Do you think in this application they would be superior to TI 1% metal film RN65 mil-spec resistors? If so, any recommendations?
TIA

Have a Yaqin (Yaoin) VK-2100 hybrid. Really like it and squeezing all the mods in I can.

Taking suggestions for a matched quad of 6n1 or 6dj8's (would prefer the 6dj8's) to replace the stock Shauguan (or however you spell it) 6n1's. The stock 6n1's just don't seem very "good".... There is no manual bias adjust.

Would prefer NOS, but only can seem to find reasonably priced NOS in matched pairs...
Looking for something REALLY good in a matched NOS quad, or other suggestions.

Thanks guys!

I bought a MiniDSP 4x10HD a while ago when I built the Linkwitz LXmini+2's and have performed some modifications and optimization.

Firstly I removed the output coupling caps and added wire links as the caps are electrolytic and not biased so will most likely be generating higher distortion. I have circled the caps in RED that I removed. Also before removing the caps I checked DC offset which was negligible. The other option is to replace the EC's with MKP's or other film caps.


After living with MiniDSP for a while I found that my MiniDSP 4x10HD was clipping at the input on SPDIF and AES but not TOSLINK. To fix this I have lowered the input gain to -6dB and increased the output gain +3dB across all 4 outputs.

What I did was to decrease input gain until loud passages did not clip the input monitor, then I increased output gain until the subwoofer just clipped and backed off until no clipping occurred, then adjusted the other 3 outputs with the same additional gain as the subwoofer.

I plan to bypass the internal output DAC's using the I2S header on the PCB at some point in the future, but the shortage of components has made sourcing high quality I2S / DAC harder to come by.

I'm in the process of building a 3-way speaker. The ports I'm using are somewhat tapered, which makes it harder to determine the correct length. I know such ports can be modeled in Hornresp, but I don't know how. Also, as Troels notes, the required port length to achieve a desired Fb can be significantly shorter than the calculated length (depending somewhat on the amount of damping material).

My plan of attack for now is to make multiple nearfield measurements (port + driver summed). Starting with the port a bit longer than the calculated length, and shortening it 5mm for each consecutive measurement. This approach seems labourous to me, I hope there's an easier way to determine the right port length based on just one FR & Z measurement.

For Sale
Pair of Fostex FF225WK 8" Full Range in almost perfect condition
Pair of Fostex FT17H Horn Super Tweeter(new, never used)
295 eur + 4% paypal fee + shipping expenses

I'm confused about heatsink C/W values. I've used online heatsink size calculators and two of the required inputs are ambient temp and max temp. I've input 25C for ambient and 65C for max temp, thinking that equals a 40C rise above ambient. Heatsinkusa says their approximate °C/W/3" values are based on natural convection and a 70C temp rise above ambient. Another heatsink manufacturer says their approximate °C/W/3" values are based on natural convection and a 60C temp rise above ambient. Based on that it seems the 70C and 60C above ambient would allow the chip temp to get 20C to 30C hotter than my calculator inputs. What am I not understanding?

Hello everyone!

I have been reading more on the instrumentation amp configuration theory and from what I understand CMRR or common mode rejection ratio is an important measurement to pay attention to when choosing summing difference amp IC (U3 in the schematics below).



Now, when designing amplifier with differential signal inputs (or balanced inputs) there are a few options. One configuration could be to use LM3886 as U3 summing difference amp and to use two LM4562 as an impedance buffers U1 and U2. In such configuration the extent to which circuit is able to reject common mode noise and interference is defined by LM3886's CMRR. The datasheet provides it in Figure 48 on page 16:



Another configuration can be to use LM4562 as a summing difference amp. It's CMRR is provided in the datasheet on page 18:



Comparing those two graphs it can easily be seen that LM4562 is better option for the summing difference amp U3.

With that said, I have a few questions:

1. If I were to use LM4562 as a summing difference amp, how would I feed signal into LM3886? Non-inverting or inverting configuration?
2. Am I missing anything as far as differential signal extraction?

Thanks in advance,
Pavlo

Made this for my Marshall Haze 40c. Now I can use it with my 4x12 or recently recovered mini stack shown here.

Just one of each needed. Anyone in Europe having a stash of these?

Thought about to make this to a dedicated topic instead of cluttering somone else' thread.
Background is, that I'm frequently in need for some upgrade of rails regulators. Trying to adapt the usual and ready available shunt and series suspects, often did not necessarily lead to the desired results.

Though the well documented specs on load and line regulation would indicate them as no brainer, the sonic signature inherent to any of this device gets imposed on the sonic signature of the stage to be fed.
On sensitive stages the sonic signature of the regulator even begins to dominate, which of course is not any desirable.
So what I'm covering here is focused to the aspect of rails being part of the signal path, a different point of view, usually not that widly noticed.

I went with a LT3045 board I got from here:
LT3045-M Ultra Low Noise LDO Voltage</br>Regulator
They are of a nice built, using good parts, and surely the designer has studied the AnalogDevice data sheet to get the best out of it, so its a solid starting point.

Inserting the +15V configured board straight away in what I will call my test setup (basically a constant current dual FET input stage), did not bring up satisfying results.
After some experiments with RC filtering of the output of the LT3045 it did show up, that the capacitors used do have a fulminate effect on the sonic signature of the amp stage to be fed.
I did try tantal, Nichicon Fine Gold and the green bipolar ones from Nichicon. Very distinctive flavours easily to distinguish.
The RC filter I varied from 150ohm / 100uF to 1.5ohm / 47uF.

When gradually lowering the R of the filter it became apparent that the LT3045 input capacitor (47uF tantal) at the board at hand becomes sort of a bottle neck. Most probably this is also the reason why just inserting the board straight away did not deliver sound wise.

So the next step was to pimp the LT3045 input with a 1000uF Nichicon FC decoupled from the PS with a 1.5ohm resistor, what in fact did turn out pretty well.
With that out of the way, as to now to me the best combination was the Nichicon bipolar at 47uF / 1.5ohm.
The Fine Gold was overly glossy and didn't went down to the bottom.
The tantal suffered in musicality but was by far the most stringent down low.
The Nichicon bipolar overall was the best compromise so far.

This was just a very quick rush through the topic of rails being part of the signal path and I am looking forward to also try some other Pana and Nichicon lytics I await in the ideal test setup I currently have available by accident. All lytics I usually parallel with MKT and silver MICA, so I did it here as well.

Regarding the basically excellent LT3045 I would love to hear your findings on its sonic signature and the modifications you possibly did to deal with.

Hi, Anybody has these mosfets for sale?

Im sticking this in a section so nobody gets upset. About posting in the wrong section.
Here is my question. How do I create a cross over with zero info on the speakers.
The issue is if you want to get speakers with all the tech specs. They cost a lot. Im talking more than 3 times the price.

Im building my speakers using el-cheapo speakers. Which come with Zero tech specs. You go to a shop. You decide what size you want and what watts.
They test it for you. That's it. I still think a good cross over would help them sound better.


Im starting out in this as a hobby. I have no idea what I will like. What will work. What will not.
So Im not going to drop a lot of money into some drivers I may like or not like. Because I have no idea what size of woofer will satisfy my need for heavy bass.
What size of mid will match the woofer. I still need to see what size speakers work. Will an 8 inch woofer work for the kind of bass I like. Or do I need a 12 inch woofer. If I use a 12 inch woofer how large should my midrange speaker be.

Have been going thru speaker box designs on various sites seeing how they combine speakers.
All I want is nice clear music with good bass. My amp will put out about 60-70 watts RMS. They claim 200 watts per channel.
Im lost and need some advice.Have purchased 3 amps. and 3 preamp / tone control boards and a transformer. I have Proteus and can test various design ideas in simulation.
Even some basic advise like for a 2 way use this cross over for your tweeter and this for you full range. And for a 3 way do this. Or a way for me to figure out the tech specs I need.
I have a function generator, a scope. So was thinking what if I do a freq sweep and see where the speaker starts to work and stops to work. Could I use that to build the cross over.

Friends have donated a lot of their DIY speaker projects. So far the best is a 2 way with a peerless tweeter with a 8 inch full range boston acoustics. It sounds amazing. But zero Bass.
Im thinking if I build a 2 way it may help me get some bass out of it.
Or should I just add an 8 inch woofer. Sorry for rambling.

Gentlemen,

I have been asked to offer another round of groupbuy for my layout of Nelson Pass ACA amplifier - modified by TungstenAudio.
I will do - but: be sure - this will be my last contribution to the ACA.

Find attached an image of my PCB offer.
It contains of:

- a LT4320 based rectifier on the left side of the image
- Nelson Pass' ACA (with slight modifications done by TungstenAudio), on the image right side
- being driven by JasonKuetemanns CapMultiplier
- if you will ever read Rod Elliotts recommendations for a (small) ClassA PSU: here we are!

I will offer you 2 pairs of my PCBs (2xLT4320, 2xACA) as unregistered mail for 20€.

Tell me if you like to have.
Best regards - Rudi

P.S.: I am currently busy building a new desktop-PC for my own needs. It will consist of:

- BeQuietPure 500 Case, MSI X470 Gaming PLUS Mainboard (from time to time I like (?!) to play "Age of Empire" or "Stronghold", or even GTA)
- 16GB PC3200 DDR4 RAM, Radeon RX580 8GB graphic card, ..

Please have a look at my setup on image2.

An USB attached ASUS "soundcard" misses any heights!
The onBoard RTC892 does not " sound any better".

How shall I go on? Do you have any recommendations?

Hi,

Thank you for helping me.

I've searched but apparently don't know the right way to search for the answer. This has to be a common design situation.

I'm building a 3.5-way speaker and trying to select the drivers.

The woofers are 200-watt RMS. I have a mid that is 150-watt RMS. And the tweeter is 25 watt RMS.

What am I supposed to do to integrate that 25-watt tweeter into the mix without risking damage to the driver?

I've never built a crossover before, but am learning.

Thanks,

Dan

And also some woofers.

are gaskets primarily for use on closed design speakers?



thanks !

Run across some interesting woofers for open baffle use they are also very inexpensive. https://5core.com/products/pro-audi...b-woofer-loud-speaker-driver-full-range-8-ohm I actually run across these by accident. The QTS 1.29 the FS 44 HZ very close to the Eminence alpha 15" but these speakers have a 60 oz magnet vs the 25 oz magnet on the alpha's. These 5 core 15's are also available on eBay for $54.49 each free shipping $47.41 each free shipping if you buy four. Has anyone in the forum used these drivers for open baffle? Someone could build a pair using two of these per side for under $200.00 that is a steel. Hopefully I will have these mounted in a baffle and give them a listen soon. I have never heard open baffle speakers before hopefully these sound great.

Dear diy-ers,

I am looking for a method to measure the maximum B+ current draw for an amp with the power supply as shown below.
Could it be so simple as hooking it up to a dummy load and opening the brown wire and putting an ampere meter where the red circle is? After that we dime it and read the meter?

Thanks in advance

Very sad news Peter has passed away only saw him a few weeks ago at Munich high end he looked in fine shape ,my thoughts are with his family.

Mark suggested that I chronicle my mini-console project. It is based (speaker wise) on the first generation CHR-70.

Some background:

It is my plan to make a special gift for each of my eight grand children as close to the high school graduation as possible. The first was a guitar amp for my grandson based loosely on the Marshall 18 Watt with a modified plexi front end. The project I am discussing here is the second project which is a mini-console iPod dock for my grand daughter.

The concept is to take the vacuum tube console stereo concept and shrink it down as small as possible while still retaining full spectrum high quality sound but still have it portable enough to move from room to room. It is not to be a portable in the sense of a ghetto blaster but in the sense of easily transportable. It compares to the traditional iPod dock in much the same way that the original Compaq Luggable compares to a notebook.

The design is still in flux and has been discussed in several other places in one form or another.

Electronics and some amp build here...
http://www.diyaudio.com/forums/tubes-valves/180141-mini-console-schematic.html

Some Layout possibilities here...
http://www.diyaudio.com/forums/tubes-valves/176015-layout.html

Laborious process of settling on an approach here...
Serious design effort begins on mini-console project - AudioKarma.org Home Audio Stereo Discussion Forums

In the end I decided on a SE KT-88 amp in UL mode with Schade local feedback. The Power amp has been built and has been used in testing various speaker possibilities.

Now for the speaker part:

I started by putting the drivers in a hacked up Onkyo cabinet which is very small and sealed just to get an idea of the sound and capabilities.



They sounded quite good with exceptional imaging and plenty of volume. The mixer that I am using for testing does not have enough gain to drive the amp to full output but still provides very loud listening levels.



It was lacking in bass so I looked into doing a ported box to get down to my goal of usable output to 40Hz. It looked feasible...





So I built a test box. (To be Continued)...

I have just found MB Quart tweeters (most 1" titanium) on a sale page but the specs and normal price list is not on the page. Does anyone know the value and specs of these tweeters? 95-6738 1" titanium, 95-6934 1" titanium, and 95-6665 1" titanium.
I never heard of this brand, any info would be a help.
thanks