If you had a choice, I do, which output Mosfets would you use, and why. Fairchild or IR. From pictures of the original Fairchild's were used, on the store diagrams IR' are used
Help

I recently acquired a pair of Decca Corner Horns. The owner had fitted them with Kef B200s and T27s and they sound very nice. However I am toying with the idea of fitting Tannoy dual concentric 8" drivers.

Question - the B200's bottom end is rated at 25Hz and the Tannoy at 40Hz. And Decca's spec for the speakers claims 30Hz. Would the horn loading extend the ability of the Tannoy to reach the lower figure?

Which begs the question - how is the frequency range of a driver determined?

I've a dozen resistors to fit together in a speaker crossover and I was wondering which is the best practice to physically join a dozen resistor terminals together.

Any addressing is welcome.

This is a little used ( about 50 hours) ACA that I don't need anymore.
I'm selling to cover the cost of the parts and materials.
It is built on a Mini Dissipante 3U 250mm All aluminum case. The main transformer is a Hammond and the raw supply filtering comprise of 80mF 35 V Nichicon KG caps (8x10000uF). Biased at 1.6A and works great.
Shipping is from 06851 of about 22lbs.

Asking $450 plus shipping.

Hi All.

Looking for your advice.

I learned that the principal partners at Cerwin Vega had a falling, and, after departing, one of them formed SoundDynamics.

I have a pair of SoundDynamics 2 Way Loudspeakers.
Largish cabinets which feature 10" Woofers and 1" Tweeters fitted with wave guides.

They are very satisfying when it comes to bass reproduction but lack in treble area. Compared to other Speakers I own they are quite flat in the higher frequencies.

I ripped out one of the crossovers this weekend and list the parts as follows:

Resister: Cheap sandcast example marked with the values 7 watt, 2 ohm.
Capacitors: One Intercap 4.7mfd 250v & a smaller Intercap 4.7mfd 100v.
Inductor: Air core, thin copper winding, 35mm diam, 15mm centre hole, & 7 mm high. Scratching the red finished wire winding revealed a shiny copper color.

What do you recommend in terms of upgrading the crossovers?

cheers

Cliff

It might be interesting to see FR measurements of drivers playing at very low levels.

I have a blown capacitor. I can't seem to find a retailer. Anybody able help out?

nichicon
820uf
160v
LKM

This is an amp that I am currently bread boarding, it is a project suggestion on the Electra Print web site for a SE 6BX7 amp....

My question concerns the 450uf el cap that connects from B+ to the cathode of the 6BX7. Is it possible that this is here by design to inject some of the power supply ripple into the cathode, so that it can cancel out with the ripple on the plate, for better PSRR?

John Broskie does something similar in this article:

But in the Broskie article the value of the capacitor is a carefully chosen ratio of mu, at 1/mu (+ 1 I think). But on the Electra Print schematic they just seem to have jammed in a big capacitor

Parafeed-Amplifier Design

John Broskie does it again in this recent 300B amp:

Two-Tube Single-Ended Amplifier & Speakers (halfway down the article)

All for PSRR benefit?

2) California Audio Labs Delta CD Transports. $185 each plus shipping.

This is a CD transport only. No analog output.

One has been slightly modified to have a 75 ohm BNC for coaxial output.

There has also been some damping material added to the internal chassis.

One is Stock. No remote for either.

I'm looking for one really big or two kinda big heatsinks.

Iam repairing a Bass two, PS damaged. Drivers are A1715 and c2814.
Each pair drives 9x IRF064N.
I have only BDA 139 and 140...only 1,5Amp curent. Can i take them? The Original can handle 2 Amps..

Hi,
New to the forum. Been wanting to do some audio DIY for over 15 years, and I'm finally taking time to do it. I've acquired parts over the years, including some nice caps. But, a primary thing I would like to do--besides making a nice-sounding amp--is use my hard-earned tube stash, which consists of some nice ECC82, EEC83, ECC88, EL34, and KT88 variants. (Also have some 6SN7's and 6V6GT's.)

The following schematic link is to a redraw of the Williamson 1949 amp by Keith Snook, who I will thank up front for his work, as clear schematics seem hard to come by. Thanks Keith!

http://www.keith-snook.info/amplifier-hifi-schematics/Williamson amplifier 1949.pdf

My question, of course, is can this circuit be made to use some combo of ECC82's and/or ECC83's with EL34 or KT88 output tubes in lieu of the ECC81's and KT66's? If so, can it be done without sacrificing sound quality? Or, should I be looking at another circuit? I don't have any transformers yet, so...

I'm self taught and can read basic tube specs and get the voltages into spec (I think), but I don't trust my ability to design circuits--yet. Any advice is appreciated.

Best,
Louis

I have some 50ASX2 SE units and a 125ASX2. The darasheet and designer manual for the 50ASX2 shows the thermal pin and describes its electrical operatiion. However it does not say whether the pin is active before shutdown so that it can be used to enable a fan. I thought I remembered that it operated at 40 degrees C and that shutdown is at 50 degrees C but I cannot now see that in any of the documents.



Does anyone have any experience of using the Thermal Pin in this way?

Hi,
recently recapped this entire amp + new output transistors (matched within tolerance of 10).
The amp still hisses in the speakers. It's only audible at max volume. It's very quiet from Tuner/CD outputs, but very loud from phono section (nothing connected).
I heard this could be caused by transistors before the main stage, there are couple of those in the preamp, they run rather toasty (60-70 degrees) and the board is discolored around them.
Anyone has any tips? The Pre-amp transistors are 2SA1124 + 2SC2632. I can replacement ones by On-semi for pretty cheap if needed.
Thanks!

Little Richard, Rock Pioneer Who Broke Musical Barriers, Dead at 87 - Rolling Stone

YouTube

I am restoring a prob 18 year old custom built 2 way bookshelfs.

Long story short, there was a long screw in the enclosure that pierced the terminal of the tweeter which is a SEAS 27TFF.

See pics: Imgur: The magic of the Internet

The terminal is supposed to be fixed, and the housing is slightly broken. I can't see where the terminal should hit another piece of metal - the housing looks all plastic to me.

Any ideas on how to repair this? seating it back in looks like it would hold actually, but for how long....

Hammond 374BX with KT88.
The transformer is almost too hot to touch. Is there a starting point on what check to find out why?
Thanks

Looking for a pair of these.

I havent bridged my subwoofers before, and looking at new amps has revealed my lack of knowledge to many things



I've been looking for some rather cheap & lightweight amplifiers for bass duty (Not the best combination, I know) to replace my current amps (Pro-line 3000 & Crown XLS 5000) to less weighing ones.
I know I will be getting a bit worse bass than what I have now, but thats a trade-off I am willing to make to reduce my 75kg rack to a 24kg one.
I will be using 1 amplifier to power two Fane Colossus 18XB drivers (8ohm /1000w rms/2000w program/4000w peak) in a reflex cabinet tuned from 40 to 80hz.


So far the T.amp TSA 4000 looks to be the best option (The only options for a new amp really being between T.amp TSA 4000, T.amp TSA 4-1300 & Behringer NX 6000), giving 2x 1000W 8ohm, 2x 1500W 4ohm or 1x 2865W to bridged 8ohm and weighing 12kg.

Wiring: A lot of amplifiers ask for a +1 & +2 connection when bridging. I've only used +1 & -1 cables so far. Do I only need to switch the end of one of my speakon cables (making it a +1 & +2 to a +1 &-1 cable, like in the first picture) for everything to be alright? Or would I have to re-wire the cabinets aswell.


TSA 4000 and bridging; The bridged option says to be 8ohm. My drivers are 8 ohm each, i've placed two speakon sockets on the back of each cabinet to allow for a parallel connection, making them 4ohm each when connected to each other. Will there be problems if I try to connect this 4ohm setup to the 8ohm bridge mode?



Since I want a bit more power than the rated RMS, How would I go about connecting these two cabs to either get a bridged connection or to get the 4ohm per channel to be able to receive 1500w @ 4 ohm per cab?

I am not really sure how to switch between the 8 and 4 ohm options from the amplifier, is it the parallel option?




T.amp TSA 4000
https://www.thomannmusic.com/the_tamp_tsa_4000.htm


Fane Colossus 18XB
Fane Colossus 18XB-8 Ohm – Thomann United States

Many thanks!

Hi all,
'ts been a long time. How's everyone doing?

I'm working on this amp, which I recapped, adjusted, measured (fairly well - enclosed), and played for hours, until there was a POP!, and I lost both channels.

Smelling something too hot for comfort from the speakers protection board (it's an early model), I measured DC voltages coming into the protection board from the outputs and I get 0.85V for one channel and 1.38V for the other. Obviously, humongous. No wonder the protection boards clamps both channels to no output (base of Q110).

Obviously, at the end of my adjustments, the values for bias and offset were pitch perfect.

It seems some sort of failure occurred, but why on both channels, and why so similar a failure?

I am torn between pulling final Qs out (which would be painful, as they're soldered), and investigating the differential input to see if a large unbalance has occurred (but why?). Maybe do some voltage-resistance on all stages, starting at end, against schematic.

Any input welcome!
aR

Guys, I need your help to modify / upgrade my amps.

I have two Nakamichi PA-1's, 5x100w channel power amps, primarily ment for HT duty. These are like 20 years old and based on Nak's "Harmonic Time Alignment technology" which is probably some derivative of STASIS as it was manufactured after their license term with Threshold.

The Good:
1 - Sound good, parallel 100W per ch, overall solid build.
2 - 910VA R-Core transformer (Kitamura Kiden).
3 - 60,000uF cap

The bad:
1 - Single PCB for all 5-channels+protection, thin Cu layer on PCB prone to failure.
2 - Asymmetric PSU - separate power transformers (546VA + 364VA = 910VA) and filters for 2-ch + 3 ch amps.

I have some experience in circuit and PCB design and frankly i am less than impressed with the skills of Nak designer. There was no need to keep it to a single PCB, could have used fiber instead of thin Bakelite PCBs, too much component cramming, etc.


Few options I have considered:

1 - Re-cap, may be swap some components with premiums. Live with the units until they are beyond repair..

2 - Since I also own a Nak TA-3 (75Wpc, STASIS) and it is the best amp i have ever heard, I thought why not use either Nak TA-4 / PA-5 / PA-7 design to make my own clones. Use the PSU +/- 60Vdc rails of the unit as is, use the schematics from service manuals to design my own PCBs and I will be good to go.
Well, I went through the schematics of all the Nak units, seems like they are too old and many components are not available. Trying to source components that are already obsolete or going into the complexity of figuring out replacements seems too much hassle.
Is it still possible to make 100W STASIS?

3 - Secondly, I went through the Peeter's "X100 back engineered" thread. It seems like a good replacement for papa's STASIS and biased slightly into Class-A like Nak PA-7, it should surpass PA-7.

Basically I want something primarily Class AB with some high-current capability with slight Class-A bias (if possible in the chassis space) primarily meant for HT multi-channel duty.
All DIY Pass designs I have come across focus on Class A. Perhaps because most people into DIY want something really clean sounding for stereo duty.

What do you guys recommend?


PS. Since Mr. Pass is very lenient with DIYers using his designs for personal, non-commercial use, I am hoping I can use one of his old Class AB designs..


PA-1, undressed!

Complete Newby here...
Some critter chewed up my Paradigm PV60R in wall speaker and I need a replacement. Any recommendations given that this model is discontinued. Also, can I replace only one, or does the other need replacement too (to ensure sound continuity). It is the Right Front Speaker in a 7.2 system.


Thanks
Sean

เป็นวงจรง่ายฯ ใช้tl494ขับmosfet โดยตรง โดยใช้R DEVIDER ควบคุมไม่ให้ G-Sมีโวลท์มากเกินไป จะทำให้กินกระแสstanby แต่ถ้าvole G-Sน้อยไป เวลามีโหลดก็จะจ่ายกระแสไม่พอ ทำให้ไฟออกตกมาก วงจรที่ทดลองG-Sประมาณ3.3v ทำงานได้ดี

Several years ago, before I started meddling with vacuum tubes, I bought a relatively popular Chinese OTL headphone amp, the Little Dot Mk II. It sounded pretty good. In my ham-fisted attempts to "improve" the sound, I swapped out capacitors and such without knowing their function in the circuit. Many lifted pads and bodged wires later, the amp got shelved away.

After seeing the 6AS7 amp that I'd just completed, my kid wants one too, but smaller in size. I remembered the Little Dot, took it off the shelf, cleaned off the layer of dust, and cracked it open. Because the PCB's so jacked-up, I thought I'd build a point-to-point clone using the power transformer. I traced out the circuit:



The front end is easy, a triode strapped pentode. The output section appears to be a White cathode follower. In Merlin's book, he has a voltage divider providing the bias for the upper triode. Here, it looks like the bias is achieved by the 120R resistor between the 2 sections. Are there any improvements that can be made in terms of safety of operation and sound quality?

Thank you.

Anyone know of a good replacement for the KTC5200 ?

They are being used in a PPI PCX2125

I have a pair of Quasar QS1 speakers. A bit of background on them! They were high-end top of their range Rosewood monitors made in 1974 by Eagle International for export from England to the USA, the deal fell through when the American dealership wanted to assemble them in the USA but Eagle International didn't trust them to do it properly. Anyway, I am driving them with a Sansui AU-11000 but I have the volume at 1 o'clock to drive them at my usual level when other speakers go to only 9 o'clock? They are supposed to be driven with an amplifier with a maximum of 50 WPC? They still had the old electrolytics in the crossovers when I first got them so I changed them out thinking that was the problem but no, it wasn't? They are still hard to drive, they sound great but I'm wondering why they are rated at 50 watts when I have to give them at least 50 watts to get them going? I thought it might have been the HF switch on the back of them getting oxidized but they are both of exactly the same volume! Any ideas anyone?😀

I'm planning on building the preamp stage from the 1968 edition of the RCA Tube Receiving manual. This circuit appears in many places, even a number of places on this forum:


https://www.diyaudio.com/forums/tubes-valves/213241-help-rca-tube-manual-riaa-phono-stage-3.html
https://www.diyaudio.com/forums/tubes-valves/301088-rca-receiving-tube-manual.html
https://www.diyaudio.com/forums/tubes-valves/156541-own-riaa-tube-preamp.html
https://www.diyaudio.com/forums/tubes-valves/129119-tube-preamp-riaa.html


I've attached the projects BOM (I'm starting completely from scratch, don't have parts hanging around). It comes out to ~$240. I want to use a tube power supply. I'm using the power supply from the RCA manual. It uses a 6X4 tube with a 300-0-300 transformer. The filter I've selected is a pair of capacitors (47 uF) and two 500 ohm resistors. Under a 60 mA load, this should put out the 250 volts I need for B+. How do I estimate the current load for the circuit? It seems under lower load, the output voltage of the power supply will be higher.





I've also added a cathode follower to boost the output from 0.55 volts to (hopefully) something closer to line level (copy-pasted from here: The Valve Wizard -Cathode Follower). I'm using this as input to a preamp that expects a ceramic cartridge output. These carts are 1.5 V RMS if I remember right.


Design goals:
- All tube design, power supply and signal path
- Passive RIAA equalization
- Standalone component from the rest of the system (ie I don't want to reuse power supply voltage from the power amplifier)
- Close RIAA compliance (within 1 dB). I know there are designs that get closer. I want to be as close as possible, but I also want a simple circuit for my first tube project.
- 60's design, this is going in a console from the late 60s, and I like the idea of a contemporary design.



Questions:
- Can I simulate this circuit in KiCAD? I can't for the life of me get reasonable outputs
- Can I save a bit and use 22uF capacitors in place of the 20 uF and the 25 uF capacitors that are not in the RIAA equalization path?
- Have I made any mistakes in the components I've picked out?
- Do I need to tweak any of the values in the cathode follower?
- The cathode follower calls for a 280V B+, I'll be using 250 V, is that OK?


Circuit schematic and BOM attached.

I want to be sure before ordering more of these for the DWM3640 Class D driver board pulled from a Hifonics. Please see the attached image.

I don't care about cost or alternate packaging. I am unsure which one to order.

Also whats the channel type actually mean? See highlighted in photo.

can i use a 811A in this guitar amp circuit?
https://www.tedweber.com/media/kits/lauren_schem.jpg

PT specs
680V/150ma
6.3V/5A
solid state rec used.

OT specs
25watt SE
5000k primary
2/4/8/16 secondaries

i wanted to build a guitar amp that was a bit unusual ish so i found this weber Lauren amp kit and loved the cool 807 tube it uses. i never messed with 807s before but after doing some closer spec checking on the transformers this kit comes with, i realized i could be runing a more powerful output tube.
then i heard about the 811A and got curious lol

but i want an opinion from people with more XP with these tubes. if an 811A is just a bad idea with these transformers & circuit design, what other tube could i use in place of the 807 in this schematic to really get some umph?

thanks!

While in my long quarantine during this Covid-19 crisis, I have so much time so I decided to built a desktop speakers for my PC. After reading numerous thread and positive comments, I plan to use MarkAudio CHR-70.3 as it fits my budget.

I know there are a lot of proven cabinet design with the CHR-70 but they are just too big to fit my desktop. So I plan to built one that have small footprint but tall like a mini tower. I'm thinking of using the design below:



So I came up with a design that is 16x16x33(w,d,h). Basically its a tall square tower.



The volume excluding the port is 4.56L and I got the box tune at 42hz and gives a 1cmx42cm port at the bottom.



I am not sure if i have done everything correctly. Is a square tower a good for speaker box? The goal is to built a good sounding desktop speaker with good bass output. I know it's impossible to achieve punchy bass with a 4" fullrange driver but at least it should not sound thin without bass at all. Or are there better driver for this task beside the CHR-70?

I'm looking for a 8-10 inch woofer that will be working in active separate bass module crossed between 200-600 hz depending on swappable mid-high modules and go down to at least f3 40 hz.
The goal is to achieve fast,musical bass that is dynamic at the lowest listening levels. I guess im looking for a driver that has high Qms , low Qts and low Mms ?
So far i've found following drivers for bass reflex enclosure :
SB Acoustics SB23NRXS45-8 ( paper cone)
SB Acoustics SB23NbACS45-8 = SB23NACS45-8 ( alu cone )
SB Acoustics 8” SB20PFCR30-8 = SB20PFC30-8 ( paper cone )
wavecor WF223BD01/02
SEAS PRESTIGE H1252-08 L22RNX/P
SEAS CA22RNY
SEAS CA22RNX
SEAS L22RN4X/P
Seas CD22RN4X
Dayton Audio RS225P-8
Dayton Audio RS225-8
for sealed enclosure :
SEAS CA26RFX
L26RFX/P
SB_Acoustics 12" SB34NRX75-6
SB_Acoustics 12" SB34NRXL75-8
Peerless SLS 10
DAYTON AUDIO RS270-8 10
Could someone that has exerience with these drivers make a brief comparison between them and tell me which one would be the best ? Im especilly interested in SB23 paper vs aluminum. Also will a bigger and heavier
driver in sealed enclosure have better and faster bass at low volume than lightweight driver in BR enclosure provided they have same f3 ?
Some people say SBA woofers are fast and some say the opposite. Which is true ?

I have had my omega for quite a few years now and I used to record a lot but now I mainly use it to listen to music or play music through my studio speakers to play guitar along with.

After a while I started getting a bad hum through my speakers and yesterday when I tried to record the hum was in the recording.

Also when I turn the monitor mix and mainly the output level I get horrible cracking through my speakers and then one or the other speaker will quit playing until I find a sweet spot that gets both speakers playing.

I thought about taking the case off and at least spraying everything down with canned air and maybe get dust out and see if that will work. I'm just worried that if I mess it up I won't be able to use it to listen to music. I have a picture that shows that even with everything unplugged the levels are up 2 bars.

Does anyone have any ideas that might help?

Sent from my SM-N950U using Tapatalk

Hi I am wondering if lets say you have a normal audio pot with two "channel"
Both channels is constructed as normal logarithmic audio pot.
Is it possible to let channel one act normal and channel two act as a reverse audio pot, just by switching the wires on channel two?

OK, I didn't have $250 for a gold point stereo 24 position 100K attenuator. So, I bought a couple of cheap Chinese ones off of ebay, see attached photos. I know, I know, let the moans and groans begin. Anyway, I spent about an hour with my DMM and for the life of me can't find the terminal that correspond to in, out and ground. Anyone have experience with these? Thanks in advance for you help.


In
|
>
>
><---- Out
>
|
Ground

I've been using Cat6a 4x0,56mm as speaker cables for more than a decade and I'm finally replacing them with 20x28AWG (picture attached) to my ears (>60 so probably deaf) they sound better.

Micro Towers - I can't exactly remember which one I came across first - the plans on Planet 10 website http://homepage.mac.com/tlinespeakers/FAL/downloads/microTower-maps-150909.pdf, or this thread by Dave: http://www.diyaudio.com/forums/full-range/148901-microtower-bipolar-ml-tl-chr-70-el70-2.html. Either way, I loved the intro... a bit of nostalgia, a bit of reviving a joy of the past... and the build looked simple, the finished speakers cute. Compact dimesions = (usually) Higher WAF 🙂, especially given that my first FR build was the BIB (pretty massive); then the plan was to build a Pensil 12 which became a Super Pensil 12 (pretty massive too).

I was also looking for speakers which could produce good bass and became very excited about FAST. After discussing FAST with Dave I had initially planned to order a pair of Alp 7 or CHR70.2En from Dave as FAST FR units. Dave's CHR70.2Ens were on sale at that time, so just decided to pick up 2 pairs... a pair for FAST and a pair for other experiments.

And then it hit me - why don't I do a Micro Tower build? According to Dave and ChrisB the MTs give plenty of bass... also the MT dimensions looked a perfect fit to me for using my left over pieces of ply board.

And so it was decided - let's go and build this! The picture below is not my buidl, but a concept build by Dave and Chrisb taken from the plans. If you take look at the illustration (taken from P10 plans), you will see how compact the speakers are (and the variations that can be made).

-Zia

I found some Adire Audio 12" Brahmas in excellent condition that somebody was selling on Craigslist for $125 for the pair. I bought them not really knowing too much, but after some research it appears that these are quite legendary. Very capable SPL and SQ, so I am excited at the prospect of being able to build some high-end subs. I am looking to build a ported enclosure with one of them for use in the home. Problem...I have very limited floor space and a wife who understandably does not want any more taken up.

I was looking into building an enclosure beneath my house. I have seen bandpass designs where just the port fires into the room, and I guess I could go that route. But I was really hoping to build a vented system. My question is, if I build a ported enclosure and both the woofer and port fired into a "chamber" that goes to the room, then is this just a bandpass? For instance let's assume the front baffle of the enclosure is 18x14 and fires into a "chamber" that is 18x14x6 such that the 14x6 dimension is a hole in my floor covered with a vent to make it look like a heating vent.

I am thinking all speakers fire into a "front enclosure" that is your room, but at some point that enclosure is so large that it does not affect design. But I don't know how large that area needs to be. It made me think of car audio...is a sealed sub in a car with a window partially rolled down now considered a bandpass enclosure to those outside the car?

Thanks

I get a nasty (high freq) buzz on the ground line. When I lift the ground connection, the system is quiet. This is on my pre amp. However any other source component that is grounded immediately introduces this buzz again -- as soon as I plug it in.

Also, this nasty buzz usually instantaneously goes away later at night, around midnight. Nothing in my house, as far as I can tell.

So can I install some type of a ground line filter? Is there such a thing? Recommendations?

thanks.
Herman

haha, i'm currently soldering some circuit and it involve a TO-3 package transistor (MJ15003).
Well.... this is the second time i try to solder such package, but both are difficult, as they are hard to wet with my solder (its my solder problem ?) They cannot 'bond' to the surface of it, which easily came off if use a small force (shaking also will do).

The problem of base and emitter terminal are not so much problem (as pad let us do easy job, but they still hard to solder than typical TO-264 or similar (which standing, not flydisk shape)
The collector (entire casing and 2 holes) surface is the most difficult, like spending most of the time doing that and FAIL !

So any guys have nice and brilliant idea or experience to share with me ? in order faster and easier to solder these TOUGH 'guy'.

hello. i have a question about pairing voltage with application.
i have a source of 12V and i need to work with a fuzz face pedal distorsion with germanium transtistors and the the pedal should get 9v.
what is the best solution for this?
i thought about a voltage regulator or a voltage divider + opamp as voltage follower.
the best solution would be the voltage divider but i'm considering a walkaround. any pro/cons?cheers

Hi,

I would like to know if any on you you know which component brand does d&b audiotechnik use in their systems, particularly:

-. the 12" neodymiun woofer in their J12 system; and
-. the 1.3" exit HF compression drivers with titanium diaphragm in their C3 system.

Sorry i post this here, but I know there are many users from europe in this forum.

thank you in advance.

I'm laying out a PCB for a passive speaker crossover utilizing air-core conductors. As I'm going about my usual PCB layout process, it just dawned on me that the copper pour/ground plane I typically apply to boards may interfere with the inductance of the air core inductors.

Is this something I need to worry about?

My recent build is a SRPP pre-amp which has too much gain for me so I will probably rebuild it into something like this Muchedumbre Buffer Preamp – wauwatosa tube factory

But I think with two halves of the 6sn7 I am using in the SRPP

Now my question is as follows:
- I use Sowter 9335 as volume control
- Switching is by relays kit from Dantimax, this works fine
- However there is a lot of hard noise while switching, really annoying. Is this because of the high gain? Or because of the relays?
- Also do I still need a grid resistor after the Sowter?

For my BHSE, I have changed the original Mullard EL34 tubes to another brand. But the sound of my left side became a bit, how should I say, veiled. The higher the volume and the higher the pitch, the more obvious, like playing songs by soprano.

This still happens after I have changed back to the original Mullard tubes. Has anyone experienced this before or know the reason?

I have discovered that the bias the bottom left tube (left offset) cannot be adjusted. Has anyone experienced this before? Or does anyone know how to fix the problem?

Thanks a lot

Hi everybody,
I am attempting to build a bass amp head utilizing a Carvin SX-15 Preamp and a DBX 1 Compressor/Limiter 262. I am looking at a 210 watt per channel (420 watt Bridged) power amp board. Typical bridged configurations only use one of the input channels. I want to retain use of both channels while in mono but I am concerned about combining right and left outputs from the SX-15 using a common ground. Will this damage the preamp? I would also like to maintain the versatility of switching between stereo and mono. Anybody have any input?

I am missing a knob for my Forte Model 2 pre-amp. I am getting ready to sell it and I don't want it to be missing the one knob. I e-mailed Nelson Pass, but I haven't gotten a response back.

Hello,


I have designed a class D amplifier board based on a TAS3251 chip (TPA3251 + DAC+ DSP in the same chip).


I now need to buy the power supply. My initial intention is to go to a Meanwell LRS-350-36 (MEAN WELL LRS-350-36 Switching Power Supply SMPS 36V 9.7A 350W - Audiophonics). I have read several good recommendations for those.


However, I'm a bit bothered by the fact that those power supplies are not optimized for Audio. They can deliver a steady 350W, while I will normally have much lower needs, but need a to be able to cope with short peaks. TI has some suitable reference designs with 200W nominal and 600W peak (from memory).


I understand that DIY is not easy in that area because of specific transformers and coils (and voltage). Drmord proposed an interesting desgin, but from the Google translate of the article (Russian), making the transformer looks like art :-(



CONNEX modules are more significantly more expensive that Meanwell. Hypex even much more.


At the bottopm end of the cost spectrum, some cheap modules like Nouveau Module d'alimentation 36V 5A AC DC Module d'alimentation a decoupage carte ca 100V 240V a DC 36V alimentation a decoupage|Alimentation a decoupage| - AliExpress


What are they worth ?


Other interesting products to consider ?


And to increase my knowledge: what should I look at for those type of power supplies. What are the interesting features / performances ? What to stay away from ?


Help welcomed,


JMF

Has anyone tried to run this driver fullrange ?
It looks fairly flat up to 10 khz on manufacturer`s graphs , with -5 db drop up to 16 khz . I was thinking about running it fullrange with aid from my amp's treble knob that starts regulating from 10 khz so this would be ideal , or maybe with help of a tweeter playing from 10-11 khz with only a cap and resistor in series.
How would it stack against the specialised fullranges ?

Hello,
How big of a heat sink do I need for Q3 in the SSHV2:
H+ in = ~200 Vdc
Regulated DC out (B+)= ~ 150Vdc
Current: 10 mA + 20 mA draw (fspare SSHV2)
Dissipation: 20 mA (150V) = 3W?

Thanks!

Abe

HI Guys,
I have a question regarding a summing amp that I am about to build.
I am posting the schematics and a picture of the original card.
could you help me sourcing this inductors and from what type it is exactly ?
We talk about L9 and L10 here.
the value is 15 uH.
thanks a lot !! 🙂🙂🙂

P

I am putting together a PA system for piano-organ-voice and harmonica playing usually in a relatively small practice space. I don't need huge volume potential but want to get a full and natural sound.
I have done lots of projects and built electric and acoustic guitars, but the only experience I have building audio speakers is years ago when I put a pair of vintage Western Electric 755a speakers in and open baffle. I loved the simplicity of that form and want to create something similar at a larger scale for practice and performance.
I am using some new parts and some items I have been using with my current setup... re-used will be a Mackie 8 channel mixer for input. New is a B-52 Matrix-1500 BBE 3-Ch Plate Amplifier (1200W w/sub crossover), two Eminence Beta-12CX 12" Coaxial Driver with PRV Audio D280Ti-S 1" Titanium Horn Drivers and LaVoce SAF184.01 18" Subwoofer.
I'm thinking of putting the 12's in an open baffle and the sub in an open "H" cab.
is that a stupid idea? and how much math do I need to learn to figure out the dimensions of the baffle and sub cab?

WTB: PCM1704

Hi,
Asking the forum help in identifying the T/S parameters of the Audax A360 Elliptical Woofer
the Woofer P/N is: HD21-32 S45

Appreciate any associated info
Pics of the speaker are enclosed

Thanks much
Harel

I have a subwoofer amp I built from an Electronics Now (remember that?) magazine article around 1992 or so. Recently it started making whoosh/thunder noises, now it just howls. I have the schematic and can trace down the parts, but was wondering if I should focus on a bad cap or something or do I have to check everything (IF I want to keep it)? Thanks for any help.

Hello people of diyaudio.

I am looking to reuse an old set of fairly well build enclosures for a new project. The enclosures have cutouts for two 10" drivers on the front panel and a removable rear panel, as shown in the attached picture.

I currently don't have the capability to make new enclosures from scratch, but i should be able to build new rear panels plus what other small changes/fixes would be needed.

The enclosures have an internal volume of about 95 liters, but i would like to use a pair of hypex fusion plate amps so i expect the volume to be closer to 85-90 liters with their box included.

I have already tried modeling the enclosure in bassbox 6 pro with a single peerles XXLS-P835016 per box and a bending bassreflex tube of 100mm radius by 452mm length that's flared in both ends. This seems to be an ok option with an F3 of under 24hz, though i am unsure if a peak vent air velocity of 18.4m/s is ok.

My goal is to get a frequency response from around 20hz to 200-300hz. I hope you guys can help me with ideas for drives suited for this enclosure 🙂

Hi there, I bought a chassis with some lettering on the front panel I would like remove so its generic. I have tried Isopropyl and nail polish remover with no success.

I thought I saw a thread on this but can't seem to find it now. I know there is one on how to put lettering on a chassis but I want to get rid of a manufactureres name on mine.

Thx in advance
Neville

New Pro offering from the SB Acoustics guys...

http://www.sbaudience.com/

By giving a hand to zintolo with his GU50 projects I came upon this circuit. The bootstrapped pentodes provide a gain of 75db ,yielding 40 ohms plate to plate output impedance for 6k load by plate to cathode feedback. The input inverter comes from Audio Research D70 , It can function without by parafeed mode but oscillates on saturation. Using Ayumi models the amp exhibits 80w with 0.03% Dtot.

Hi
Anything out there
Cheers all

Hi
someone can help me with schematic of this AMP?
i need full schematic for this AMP.

Hi,

I have an issue with my Audio Note UK Model Soro SE Integrated recently.

My Soro SE is the model with ECC82, 6SL7 and 6L6/5881 tube.

The audio playback will begin to be distorted, especially obvious with mid range like vocal after power up for around 35 mins to 40 mins. The duration the audio playback begins to distort is always similar each time. This problem seemed to be related to heat, maybe some component is not working properly when heats built up.

if you have a similar experience and can advice what is the likely cause of this issue. Do also share with me if you have the schematic of this amp.

Thanks.

I picked up a set of DIY speakers with Vifa drivers. I am trying to determine who's design it is. They are 14"H X 6"W X 8"D. Made with 3/4" MDF. They have PerfectLay inductors, Solen Fast Caps and Lynk metal oxide resistors.

I need help to fix my Plinius M8. Specifically its Toroidal Transformer Power supply. Attached here are the pictures of the unit and the drawing. I was hoping if anyone could give me a data sheet or complete specifications of the power supply which is the Toroidal Transformer of the Plinius M8.

Hello. Look interested in the phase of the harmonics. Voltage and phase in degrees circled in color. Do not always get low values, does this make any sense?

Hello, 🙂

I'm planning to attenuate the tweeters in my speakers.

With my new amp, the upper midgrange and the top end can be a little bit on the cold side on some recordings.


I was planning to use metal oxide resistors, but I got some advices that I could try carbon film instead.

It turned out that some manufacturers are using bunches of 10 or more carbon film resistors connected in parallel:






Upon further reading, I found claims that metal oxide resistors are technically "better" and more precise, but that they can be cold sounding.
Carbon films are technically inferior, but they are warmer, more musical, etc:

Carbon Film vs Metal Film revisited


So guys, do you have some/any experiences with carbon film resistors in speaker crossovers?!

In my country, the choice of high quality components is very limited.
These are the carbon film resistors that I can buy at this moment:
Cinetech Ind. Co., Ltd
http://www.cinetech.com.tw/upload/2011/03/20110330164634.pdf

What do you think?

Thanks in advance,

Aleksandar 🙂

This is my small, minimal and very simple stereo amp for tablets/smatphones.


All components, eccept tubes (NOS), are recycled from old non-recoverable radios (resurrection from the grave)
The chassis is from an old Phonola radio from the early 1950s, upside down from what it was originally to obtain a support surface for the smartphone
The two little lamps (2x6V in series) on the side, are used to light up the smartphone (at night)
The big filter CAP was put close to the output transformer because I needed to cover a big hole
I choosed 12AT7/ECC81 and 6AK6 because their very low heaters current (power saving), you might try to use ECC82, 12FQ7, ECC83 at place of 12AT7 (same pinout), and use 6G6G (same tube different pinout) at place of 6AK6
For smartphone recharging I used a cheap 12V to 5V car audio USB power supply

NOT SUITABLE FOR CHILDER USE, SHOCK HAZARD!

Note: I am planning to add a small Bluetooth module (recycled) to this amplifier.




Output Power 1+1 W
Output audio transformers: 10K SE (EL95/ELL80)
Tubes; 12AT7/ECC81 - 6AK6(=6G6G octal)
Total heathers current: 0.3A @ 12V
note: 6AK6 heaters in series (6+6V)

Main voltage: 110/120 Vac (about 135-150Vcc after filter cap)
Output: 5Vcc 1A for device recharging

Pair of SEAS Prestige CA15RLY (H1216) 5.5" Coated Paper Cone Woofers.

Brand new unopened box.

Retails at £70 each. Wanting £120 for the pair plus postage.

As I await my delivery of a bare board pre from Tortuga (single ended unbalanced LDR) I will be encasing it ans wiring it up to input and out sockets. I would rather not use RCA phono, because I am feeding the pre with a DAC that has balanced out XLR, and a phono set from my turntable phono amp. The pre then outputs to a DBX Venu360 (also XLR) to do digital crossover into two sets of power amps to drive a pair of hybrid ESLs.

I also like XLR plugs from an engineering standpoint and have all the necessary balanced quad core cables, so don’t really want to rip them apart to make a balanced to RCA cable.

So my plan is to wire the XLR sockets and plugs in the amp to treat them as single ended.

There are many views on how best to achieve a balanced out to unbalanced in and unbalanced out to balanced in. My research based on this site Dealing with unbalanced gear in the studio - Crookwood leads me to the following plan, though I have to confess the more I think about, this more confused I get. Especially as what I am doing is a little different, in that I am trying to preserve standard XLR cables and get the right result by correctly wiring up internally. The DAC is a Chord Hugo TT, metal chassis with wallwart DC power (not sure if that makes it a floating or mains earth, I am guessing floating) The DBX is a pro unit with earthed mains in, so I am assuming this is a mains earthed unit. It also has a pin lift that can help with earth loops)

Please let me know if you agree or have a better suggestion.

For the input from the balance cables from the DAC

Internally within the amp, wire the hot pin 2 to the board, connect pin 1 and 3 together and earth on the chassis, or should the earth be taken from pin 1 and 3? The earth to be chassis earthed in a star.

For the output from the pre to my DBX, wire the signal +ve out to pin 2 again, and again connect pin 1 and 3, wire this to the -ve output signal.

Any help would be gratefully received

I got the Hifonics Brutus BXi1100D amplifier.
Unfortunately, someone was fixing it. Missing items.
What should the transistor Q101 be like?
The transistors in the inverter are IRLZ44N?
Power transistors are IRF3710Z ??

Dear all,
Anyone out there offers parts and PCB for Borbely Millennium 75w Class A monoblock?

Thanks!

Got this amp, repaired ps.. I have removed all output fets, because they was heating. Checked and found no oscillation. Now tested with injecting a signal, then oscillation starts. Maybe the mosfets are not good.. I will continue when I receive new parts.

Anyone know where I can buy new rca jacks for this amp or a part number ?

Hello, I have three amps, based on this design. What are the common drive board problems? Output fets are irf9640 and irf640n. I have high and low side drive, fets get hot quickly. On another amp, there is jo drive. Checked all parts, changed lm393, drive OK. Fets get hot. What is the right part number for the drive transistors AG and dk?

Came across a stock of new, unused parts from my early designing days, all from US sources. If interested, send me an offer:

MC35084L Mil Temp Quad Op Amp -- qty 40
MC33282 Quad Op Amp -- qty 20
MC33282 Dual Op Amp -- qty 20
AD536AKD/AJD RMS to DC converter in CERDIP -- qty 8
Intersil / Harris / Maxim -- qty 20
OP97F -- qty 20

I also have some values (40 ohms, 301 ohms, 1K, 5.69k, 825 ohms and some others to be catalogued) of 1/4W PRP 0.1 to 0.01% TC25 resistors from the early 2000s. Practically hundreds of each value.

I will continue to add as I find more. Again, if interested, please PM.

Got a question for all you Digital folks!! I don't much dabble on this end, as it has mostly been set Digital DAC up and forget it if it sounds good (and it does).

I have an AMR DP-777 SE DAC connected to my computer (spdif off mobo).

I have the following option for DAC inputs:

Option 1: 2 x AES XLR / BNC

Option 2: 2x Toslink / COAX (RCA

Option 3 1x USB Asynchronous

All the above go thru a 6922 (or a 5670 with adapter) Tube stage after DAC and out to the preamp.

Now Option 1 is the extra special HD Digital input that goes thru another tube (6H11), and is supposed to be the recommended connection. I currently have this connected via a cable I made - BNC/COAX terminated with an RCA to computer.

Here is the issue... my computer is around 15 feet away from my DAC, and using Toslink, COAX (RCA) and BNC cable I have issues locking at rates over 48khz...cannot lock on 88khz, 96khz, and 196khz. Currently set at 48khz with no issues.

And yes, I know I could move computer CLOSER to DAC... and would rather not just purchase a $300 special magical cable to 'try"... just trying to look at the obvious things first...

Now my questions:

* I have another computer I am considering making the SOLE music source - like the one now, I get all spdif off mobo...maybe swapping computers may have stronger signal drive so I can get over 48khz to DAC?

* Async USB input may get me the higher rates (only one that does 196khz methinks), but has a cable length maximum of 5 meters - around 15 feet, correct? And the USB input does not go thru the magic 6H11 tube like inputs on option 1

* I have a sound EMU 404 sound card I can throw in my computer that may have the additional Signal drive to get that higher rate signal to the DAC...could this help?

* I am using Chrome (Pandora on hi rez) and iTunes - nothing here would matter on getting higher rates to DAC, right? Current rates set on Windows...

* Is 48khz sampling good enough? Am I kidding myself thinking computer output at higher rates would make a world of difference? I do have a couple higher rate downloaded media...

* I can get 48khz input, and upsample to 88khz or 96khz (or 196khz maybe) - theoretically, worth it and better than straight 48khz? Same input rate signal tho...never quite understood how upsampling would make a difference...

Appreciate the help!! Go easy on me, please!!

Hi all
This is my first post and I’m new to diy hifi(always just bought it😂)
I’ve got some Rogers ls55 speakers that I like a lot but are looking tatty and they seem to be quite poorly built chipboard so I was thinking of having some new cabinets made (I’ve emailed wilmslow audio)
Or I could build some myself what’s the best route to take what material to use etc will it improve the sound etc or should I just buy new speakers🤣😂🤣😂
Any help would be great fully appreciated
Cheers
Scott
Ps my dad loves a bit of woodwork and has a garage full of tools table saw etc

Having problem with my NAD C350. Circuit protection activates approx. 5 seconds after power on, with or without speakers attached.

Any ideas or a link to where i can find a circuit diagram?

Thanks in advance!

//Bengt