Supravox 215-2000EXC mached pair.
condition is mint.with original boxes.
used for few years and are for sale as im going to home cinema system.
also have power supply for them made specialy, for additional price
looking for 1800 eur + shiping.
im located in Lithuania, so European buyer is prefered.
pictures if needed i can be sent in private

as new,with boxes, used for 2 weeks, cant get corect match for my system as supertweeters, so going for sale 🙁
pair 800EUR, + shiping
condition as new, no scraches and etc... not bolted on speakers, so mint condition.
PM if interested. they are in Europe.

for sale :EMT Haufe T94/2 MC transformers pair 1:20
price 650 eur.
pictures if needet to PM

Just wondering what a few different people are using and what they have tried-ive got a set of Acoustat spectra 11s and im trying to figure out wha type of wiring I should use- I also need to buy a new set of XLR cables so id like to hear what you guys settled on for yours-silver wire Ive found has a horrible bright sound with my speakers😱

I've burned through two of the Chinese ("LJM") CM6631A-based USB-->I2S/SPDIF converters and rather than buy another one I want to try something different.

I gather my main choices are XMOS and Amanero. I don't want to buy a sub-standard implementation of either, but I don't want to spend ridiculous amounts of money either.

All I need is the finished board - I can manage the chassis and power (if required).

Running Linux and PCM audio only, dumping I2S or SPDIF to an assortment of DACs based on my mood.

So, XMOS vs. Amanero and any recommendations on which specific boards are decently implemented and good value?

Thanks in advance!

I'm still at it ... trying for more power , better devices , and keeping it simple and reliable. While reading a little Douglas self (amp handbook), I ran across this statement :

"type 3 is as equally good as type 2 at reverse biasing the output bases, and may give even better HF turnoff as the carriers are "swept" away by a higher resistance connected to a higher voltage" "this remains to be determined..."

Click to expand...

This seemed to deserve more investigation , and the best test was my new triple using njw0281/0302's (drivers) - njw21193/4's (outputs). The 21193/4's have HUGE dies (hefty Cob) , lower gain/Ft and killer SOA. After I plugged in the models for the 21193/4's , I noticed more Xover distortion even as I was driving them with smaller OP's. I then tried the type 3 driver config (1st attachment). This seemed to run most nicely in class A (attachment 2) , and to my surprise halved my THD20 ,plus reduced (considerably), the Xover artifacts being fed back via NFB. 🙂

This also brought up the question of model quality as the NJW21193/4's are newer to-3p ON devices and the models, (like the fairchild KSA's) seem to show the device in great detail (Cob , saturation "effects") versus "stupid" models - (mje340/50).

It was cool that the simulation showed what Mr. self predicted ,..smoother Xover from 10k up , rounded corners in the Xover region at HF ,and a nice class A driver region (70ma average).
Has anyone built something similar ??? I'd love to hear about it .
OS

BTW , WOW... what a improvement in the forum !!! 😱

First post here.

I have a NAD 304 that i use for music while i try and finnish an amp based on a gainclone design. I turned this on yesterday to find the light was staying on red, and a smell of burning comming from it.

Searches have shown me that Some resistors should be changed, specificly R333 and R334 to 1 Watt. I have checked the resistors and they seem fine, but am about to change them anyway as i have some spare 1 watt resistors lying around.

are there any other idea's as to what is causing this - has anyone else experianced problems like this and it not been caused by the Resistors?

Thanks

Thorens TD 125 in near mint condition. Original base has been lacquered in black. New maple bottom plate. Board drilled for SME 3009. Cleaned and lubricated. Perfect pitch control in all three speeds. New Thorens belt plus a new German belt, power cord, copies of owners and service manuals. Extra Linn felt mat. Will provide blank arm board if required.

Obviously being stuck at home gives us all opportunities to get creative so I set out on a journey with some goals:

1. Use up some of my spare parts and tube stash.
2. Create a 5 watt amp, which is all the rage and will also replace my awful solid state shop amp given to me.
3. Utilize this spare Epiphone Century reissue chassis and output tranny.
4. Utilize this mystery smallish power tranny I scored at an estate sale.
5. Create a signal tracer probe to utilize with my new shop amp.

Looking at my tube stash I came across a bunch of 6AS5 pulls. Although the data sheet only gives a Class A example for a car radio, I didn’t see any reason why I couldn’t use these in a push pull setup assuming I can get the screens low enough and the tubes biased correctly. Each tube is around 2.2W, so a PP set of these should yield something close to 5W. Bingo. My power transformer appears to be a 250-0-250 design with only a 6.3v winding. Looks like I will have to go with a solid state rectifier. Here is what I came up with. I realize I am pushing these 6AS5’s beyond their limits but I really like the sound of this amp and will likely leave it unless you all see something egregious. I may add some NFB or may be some tone shaping switches, not sure yet. The screens were the challenge trying to get them down to 110V... I got them close. After about 5 years of repairing gear on the side this is only the second time I have tried to build an amp so be gentle. I really like the way this sounds. Here is the schematic, gut shots and a video of my brother playing it. As a bonus, I noticed these 6AS5’s are on sale for $1.95!

YouTube

If I am using for example Frank's 6sn7 line stage and its grid resistor is 1M and it has a input control of 100K what is the impedance of this? Wouldn't the impedance change with different volume settings?

What about figuring the impedance of the line stage section in my phone preamp that has a grid resistor of 221k but has a volume control after the input tube with a resistance of 100k?

Any dac ic good for measurements and listening?

Akm burned.
Ess has IMD hump issue.
Cirrus is over priced.
R2R from analog do not support 24bit.
Ti dacs poor specifications except obsolite ones.

What do you think about this?
Is there any dac chip out there both good for measurements and listening?

You have made all kinds of speakers, and have your own subjective feeling about them, how you hear them, how they place you in the "world of music." Do you hear them as omnidirectional, or just have to sit in the sweet spot area? I am interested in what your ears perceive, not what the mikes/instruments hear.

I have my thoughts in immersing in the world of music, within my normal living room, but before stating them, I'd like to hear of your subjective feelings. Thanks.

Having looked at the data sheets I am a bit confused as to how to correctly connect these in a power supply. I am using 30 uf 700 volt with 4 pins. Which pins connect to ground and which to the high voltage? Some of you may know that the cap is oblong with 2 pins at each end. So do the 2 pins along the long side form one connection, or is it the 2 pins at the narrow end that form a connection. Hope I have been clear in my description😱 May just go back to conventional electrolytics as these are bulky with no obvious way of mounting them🙁

MDD (Multi Delays Diffraction) is an innovative technology for loudspeakers.

MDD uses acoustic diffraction to emit coherent secondary sound waves, delayed by a few milliseconds at different points in space.
The 34c9 project is the first compact version made with MDD technology. Other features of the 34c9 project:
- zero internal acoustic reflections,
- sound insulation from the floor in the audio band,
- omnidirectional emission on the horizontal plane over the entire audio band,
- no damping material,
- 3FE25 speaker from Faital-Pro.

More information at links:
Claudio Gandolfi - MDD
34c9
Pinterest

My current working hypotheses are described on the page acustica.

The last projects reported in the full range and planars-and-exotics section:
MDD3A89 an MDD project with the 3FE25 driver
https://www.diyaudio.com/forums/planars-and-exotics/342677-mdd-multi-delays-diffraction-multi-tl-omnidirectional-single-drive-15.html#post6437638
other documentation is published at MDD3A89.

54m42 54m42 an MDD project (42 alveolar polypropylene wave guides on one driver)
other documentation is published at 54m42

66c9 66c9 a low-cost MDD project (paper waveguide for educational use)
https://www.claudiogandolfi.it/66c9.html

22D7 Two drivers per channel for a 3D effect
22D7: four MDD systems for a 3D effect with omnidirectional speakers
https://www.claudiogandolfi.it/22d7.html

22M7 Simple and inexpensive wide-band rigid PVC project.
https://www.diyaudio.com/forums/pla...nidirectional-single-drive-4.html#post6006473
other documentation is published at 22M7.

22C71L8 One driver per channel with waveguides applied to the two sides of the cone.
https://www.diyaudio.com/forums/pla...nidirectional-single-drive-5.html#post6017746
other documentation is published at 22C71L8.

MDDHX135 an MDD project with the HX135 driver
https://www.diyaudio.com/forums/pla...nidirectional-single-drive-6.html#post6124020
other documentation is published at MDDHX135.

MDD3FE25 an MDD project with the 3FE25 driver
https://www.diyaudio.com/forums/pla...nidirectional-single-drive-8.html#post6170069
other documentation is published at MDD3FE25.

Hello,

This is Onur. Actually I got help in this forum almost 2.5 years ago before I visited my friends in USA. At that trip and afterwards I got some drivers but didn't have time/resources to build something. Actually, I put two drivers in a PVC pipe and used them as atmos ceiling speakers, not sure if it counts 🙂

Right now we are in the process of moving into a new place. I have a dedicated home theater room 320 x 550 x 230 cm (w x h x d - 10.5 x 18 x 7.5 feet) and finished the cabling.

I will use nylon/spandex acoustically transparent screen (around 120" 16:9 or 114" 2.39:1) and put speakers behind them.

I would like to get your opinions around what to do for LCR speaker setup.

What I have in hand:

1) AV123 Strata Mini (tower speakers) - pair
2) Stone Image Audio Rothschilde A2 (bookshelf speakers) - pair
3) Wharfedale 2180 (pro speakers) - 7 of them
4) Visaton BG-20 drivers (BG 20 - 8 Ohm | Visaton) - 3 of them
5) Visaton DTW 72 drivers (DTW 72 - 8 Ohm | Visaton) - 3 of them
6) Tymphany TC9FD18-08 drivers (TC9FD18-08 - Tymphany) - 7 of them
7) subwoofers: infinity 1260w in a 45x45x50 cm enclosure (around 90 liters) - 2 of them

I am thinking to use strata mini's in the living room, not in the home theater room; but, if I use them in the HT room I found a center kit with the similar atohm drivers with the mini's (Kit Sirocco C.1 - ATOHM).

What would you do? Which drivers/design would you recommend for my application?

Best,
Onur

My dad has always been into hifi and spent a lot of time down at the local hifi shop where the boss (who sells very expensive stuff all day long) put him onto the Electrocompaniet amp.

I've listened to it a lot when I was much younger at home but not heard one for a long time.

Anyone else have any experiences with this amp and able to verify the claims of its supposed goodness?

Finished product: The 2 Channel Audio Amplifier | Inner Magazines

Background design info: The legendary Lohstroh-Otala Amplifier revisited | Inner Magazines

Hello everyone, I am trying to repair a PSB SubSonic subwoofer that I bought recently for cheap (for obvious reasons).
I obtained the service manual and started doing some basic tests. Seeing that the amp wouldn't power up at all or show any signs of life, I decided to first test the power supply. This amp uses a SMPS that has a pwm control to change the voltage of the supply rails continuously with changes in the load.

I had a look at the schematic and tested the voltage at the specified points, only to find that pretty much all the voltage readings I took were no where near the specified voltage, leading me to believe the power supply is faulty.
Some of the voltages were higher, and some were lower than what they were supposed to be. Another thing that I noted was Q401 and Q402 would get very hot, too hot to touch and they only share a smallish heatsink.

Another observation was the the power supply is audibly noisy in operation, sounds almost like a camera flash unit as it charges.

I have a basic understanding of SMPS's operation, but very little experience with them and I do not know what the best route for repair would be. It is no problem for me to remove components either partially or fully to allow out-of-circuit testing.

From what I have described, are there any common failure points that I should investigate first, or is there a procedure to trace the fault? I could simply go through and replace all the semiconductors and capacitors, but I would no doubt be replacing a lot of components that were perfectly fine, along with no guarantees of actually fixing the problem.

Any help would be greatly appreciated, I hope to learn something from this exercise so I don't want to simply replace everything until it works, as I may not even fix it and spend money for no reason.
Perhaps a couple of components failed and caused a cascade where their failure triggered other parts to fail? I do not know, so I thought I would ask here as I'm sure there are some experts on the subject. Thank you for taking the time to read my post, if you can help in any way I would be most grateful for your time and advice.

I am thinking to implement an active DSP configuration into my system.
I will use 3 way speaker and I already bought a protection cap for the tweeter.
(Acoustic Energy Aegis Three, Acoustic Energy Aegis Three Floorstanding Speakers user reviews : 4.5 out of 5 - 28 reviews - audioreview.com)

To do so I should remove the passive crossover and wire each speaker directly to the amp.

Doing so, I wont be able to use them without my actual complex active DSP configuration which in my case is a PC, running Equalizer APO, external sound card and four stereo amplifiers.


My question is, could be posible to maintain the original passive crossover/wires to speakers and connect also the new wires to the speakers?

Then, just connect the amp to the new entries and leave unconnected the passive XO entries. I am concern about having the XO circuitry on the other end of the speakers

I made a diagram, I hope it understandable.
The speaker have bi-amp capabilities. One channel for the woofer and the other for mid and tweeter.

I’m in the process of setting up a tube amp testing bench, and have built an 8ohm dummy load with BNC connectors to connect an Oscilloscope. Before hooking up anything “important” I thought I would test the dummy load with a cheap chip amp, but this amp has a built in speaker short circuit protection. Hooking up the dummy load on the speaker terminals seems to trigger this protection circuit, which was not what I expected.

I’ve verified that there isn’t a problem with the other connectors attached to the dummy load (the oscilloscope) by taking another 8 ohm resistor and hooking it up across the speaker terminals directly, with the same result.

Since this isn’t what I expected, I thought I would appeal to the collected wisdom just to get some feedback, before hooking it across an expensive output transformer. Have dummy loads been known to trip protection circuits?

Hello I am trying to choose a psu to power my class d module, and i am interested in finding out if there is any meaningfull diference between the 3 stated psu. More specificaly the psu in question are: a generic laptop power brick, a mean well smps (MEAN WELL RS-100-24 Switching Power Supply SMPS 100W 24V 4.5A - Audiophonics) and a connex smps made for use with class D amps: SMPS240QR ( SMPS240QR | Connex Electronic ). Especially given the diference in price 20 euro for the laptop psu, 30 for the mean well and about 60 for the last one. i knwo there is a diference in voltage but that not my main concern. They are to be used for a powered- active one way speaker with an indigraded class d amp propably one from sure electronics/wondom/dayton audio. The amp is going to be conected with a pc and i fear of forming a ground loop especialy sience the pc is grounded as well as the psus u mentioned, expecpt from the case where i use an extremely sceatchy ungrounded cheap laptop psu (or i dont connect the groudn wire inthe other two). Would the psu play a role in noise and ground looping given that it's a speaker ment for critical listening but not very high end.

i've been looking for more info and hopefully drawings of these cabs manufactured under the name Butterfly (and if i remember the badge correctly in small letters it said "by Tube Audio"

Hi
I am looking to fix the output board from a micromega 3 with the drive 3 digital output board .
the cd player works fine just nothing on the output
I have removed the board and removed the large diode which is a 1N5349B which is a 12v 5w zenner this tests as shorted out
the 2 diodes are good the resistor between them is burnt but still measuring 25R
could it be just the zenner needs replacing or because it has gone short will that have damaged anything else .
I have tried to test the 5 voltage regs on the board by testing between pins with a diode test on my meter which bleeps so no shorts or it would be a continuous tone .
cant seem to find a schematic any where !
any help much appreciated
Glenn
20181124_143950 by glenn jarrett, on Flickr
20181124_144033 by glenn jarrett, on Flickr
20181124_144016 by glenn jarrett, on Flickr

Greetings!

I'm looking for cheap 4ohm Subwoofers and found the RTO-1000 on Ebay. (RTO das Original! SUPER-SUBWOOFER fur PKW und Home STEREO 2x 180W 2x4 Ohm 255mm | eBay) But the TSP the seller states there are different from the TSP's that are listed on that website: TSPs vieler Chassis

Does someone know wich ones are correct or has other sources? I Couldn't find other datas for that speaker in the internet, but there should be old cataloges of RTO and Audio-Hifi newspapers that stated the TSP between 1994 and 2002 as the second link states as source. Maybe someone got the same speaker and still got the correct data? I already contacted the ebay seller, he dosn't know why its different and just says they normaly check everyting carefully but couldn't provide anything to proof his data.

Cheers!

hi Guys,
i have this running in my truck for about 6+ years
still working perfect, but i randomly decided to open it to give a dusting, and found this: the big capacitors ( few of them have little bulge )
expecting them to blow soon?
should i replace them to prevent it dying ?
its pushing 2 x 12" ss t7, ported, and its awesome .

I am wondering if anyone on here has built the Circuit Basics LM3886 amplifier exactly as shown on the web site?

What did you think of it?

A Complete Guide to Design and Build a Hi-Fi LM3886 Amplifier - Circuit Basics

Thank you,

David.

I wanted to do a very quick sim to see how these drivers stack up. I fully realise that real world influences will affect performance and sound but am I right in thinking that the Alpairs don't have quite the extension of the EAD100 (JX92) in a BR application?

After finding out my RCA "ETI Bullet" plugs are too bulky and tight for vintage gear I am now looking for compact, cheap but decent quality replacements.
Recommendations please?

like this, and where to source them?


thanks!

I replaced U1 in the oscillator with an AD797ANZ and I get way too much THD. Any compensation I need to do for it?

4 pieces of Morel CAW-428 4" woofers for sale, new, unused. IMHO, one of the best 4" mid/woofers.

Morel CAW 428 4" Classic Woofer

Price 50€ per piece + shipping.
Regards

Where can I buy recone kits for Speakerlab 1208R speakers

WARNING! Extremely newbie questions to follow!

I am the original owner of a pair of Time Windows, circa 1977, which I would like to get working again. There is no sound coming out of any of the tweeters. Are they likely to be my problem, or is it more likely the crossovers? I have contacted DCM, and they have a suggestion for replacement tweeters (PartsExpress, part number 264-500). Has anyone out there attempted to work on rebuilding these speakers? Or, can anyone recommend a shop in the San Francisco bay area?
Thanks in advance,
Dan Clark

Dear friends, I need some help. What is the easiest way to reduce ±60V to ±15V with sufficient performance?

I initially plan to use LM317 tracking preregulator circuit and add TVS diodes for clamping protection. Doing so can meet the requirements while getting the powerful performance of LM317 and is relatively simple, but there are some problems that have not been resolved:

1. At the moment of starting, due to the need to charge the load capacitor, the load will be exposed to a dangerous environment far exceeding ±15V.and the LM317 is easily damaged. If I use 30V TVS diodes on each LM317 and connect 17V TVS diodes in parallel to the output port, can I effectively protect the load from overvoltage damage?

2. At present I know that LM317 can make a tracking preregulator circuit to achieve a voltage drop of 50-60V. So, can LM337 corresponding to LM317 make negative voltage tracking preregulator circuit?

3. I considered using LM783, but it does not have a negative voltage LDO.Are there other more concise high-performance positive and negative voltage regulator circuits?

thank you all!：D

I replaced a 10K Ohm plate resistor in
a common cathode stage
by a 10M45S (5K trimpot, 1K grid stopper)
10mA constant current source (CCS).

I heard a small pop/thump sound momentarily AFTER power down the amp,
didn't have that with resistor.

Out of the 5 "identical" copies of 10mA CCS that I made,
only one doesn't have this issue.

I have also tried cascoded CCS, 10M90, various trimpots
... the "pop" persists.

I wonder what would cause this "pop" ???

Would it be some kind of residual current in the CCS
(like a choke which can be fixed with a flyback diode ) ?
The 10M45S CCS does not have energy storage ?
So I tried the flyback diode .. I tried bypassing the trimpot
with 10Meg resistor .. both didn't work.

Suggestions ? Insights ? TIA

Anyone have a service manual for this amp?

I'm need the value of R348 and Q311

Please BST Liker 330 shematic pdf.... Email: norbbie@gmail.com

I moved from the US to Singapore about 10 years ago. I had my Monsoon PlanarMedia 9 system shipped with our household items and I'm just now digging it out (yeah, it takes me a while to unpack).

My PM-9 is rated for 120 VAC 60Hz but here in Singapore, the supply is 230VAC at 50Hz. I assume that the frequency difference in this particular application won't be critical (is that correct?). I'd like to swap out the onboard transformer for one that will work with the local supply. I'm not a complete novice, but I haven't done much electronics DIY since moving to Singapore, so I suppose it would be appropriate to respond as though I am a novice.

The markings on the transformer are:

HK76H-129
TTI1201C014
BUILT IN THERMAL FUSE
0233

And on the side:

DAR PLUS A

I can't find any info on this part, and therefore, I don't know what the output should be. I also don't have an external step-down transformer in order to be able to power up the unit and test the output.

Does anybody know if I can simply swap out the transformer in this application? Any idea of the transformer output or how I could measure it?

(I have a few pics of the transformer if that will help--just let me know if it's necessary to post them)

So a friend gave me this cigar box. I had to do something with it...

It is a line stage using ECC99 dual triodes. It runs from a 12V external power supply.

I designed a non-isolated flyback converter (switching power supply) to generate a 200V B+ supply for the circuit. There's been some discussion about such a thing here lately, so here's a working example (albeit low power).

Also, I built a muting relay circuit to keep the outputs off until the tubes warmed up, to eliminate the big "thump" you can otherwise get when the output caps charge up as the tubes heat.

All the details are on my website Pete Millett's DIY Audio pages.

Pete

have much more amp parts half price or better might swop for 6GB8 Toshiba's or 8417's - WHY?

For Sale:
gently used Bottlehead Foreplay preamp kit. Built this back in about 2002 and used a handful of times. don't recall much on the specifics, but it's been sitting in a box for a LONG time. have some extra tubes as well.
Asking $100 obo

will ship at buyer's expense. Paypal for payment please.

thanks for looking

Pair of Lundahl LL1630/10mA

Selling a pair of Lundahl LL1630 preamp output transformers gapped at 10mA.

These are single ended preamp output transformers. They have a
a 7.2:1 step down ratio, and are gapped for 10mA unbalanced DC current.

Suggested uses:

• A traditional configuration with a single or paralleled 6SN7 sections, depending on the operating point and current you want to run. One section run at 7-10mA works, or you could parallel two sections at 5mA each.
• These are ideal for a high-gain, low-Rp tube like a 5842/WE417A line stage run at a more sane 10mA of plate current for a more delicate sound.
• The above 5842/417A would also make an excellent first stage driver for an LCR RIAA circuit.

These were originally designed to be used in a special configuration (paralleled primaries and secondaries) in the Ciuffoli SESS Tube Headphone Amplifier using the 5842 tube.

Asking $170/pair plus shipping from St. Louis, MO 63108 USA.
Please feel free to email with questions!

Thanks,
Tom

I have a tube amp using two different types of valves with different heater requirments and due to some shortage of components, as i have 7 regulated heaters, i chose to regulate the last two heaters voltage using two different types of regulators supplied from same positive 12V rail.
I chose LM317 for the lowest noise tube with lots of gain which ask for 300ma of current and lm7906 for the power tube in the chain which is also the hungriest heater taking 750ma. I know lm317 could supply both of them but i don't need too much stress on my regulators .



The question is:

how is the 7906 line ripple on GND line going to affect the LM317 output noise and how should i wire those circuits the best way to get the best immunity, let aside the decoupling capacitors required for best performance?
Honestly the heater noise isn't critical in my system , the regulation is used just because i don't have 6.3v windings on my transformers, but i am really curious about the best technical solution for the future.

Empire 208 Turntable Project

Selling a working, but currently disassembled, Empire 208 turntable, no tonearm, no plinth.

The motor was removed for testing and R&D with 3-phase motor drivers several years ago, but the project was set aside, and it has been sitting in a box for too long. Maybe it can become your project? 🙂 The motor is easy to reinstall. Three wires, color coded, to reattach, and two ground wires. If you want me to rewire it before shipping, I can.

This unit is cosmetically average (you should see some of them!), but was in good working condition before the testing. I borrowed a belt from a friend's 208 and it ran well and to speed. The motor mount grommets are pliable, but original. The motor cover is present, and has a 'dust bug' mark on it.

Asking $250 OBO. I'm most flexible if you take it as-is, as I'm trying to clear out things and make time for current projects!

Bullet proof packing, and fast shipping from Saint Louis, MO 63108. Thanks! - Tom

Hi there,

anyone a clue how to run a Cyrus Two/PSX combo as mono versions. I don´t understand how to connect a record player when running 2 Cyrus Two as mono blocks.

Thanks for any comment.

Best regards

Rad

I am working on a hiraga 30w amp, it has an iddle at 1.65 amps and produces alot of heat, I was not happy about die temperature versus heatsink temperature.
I bought a very fine coarse wetstone for sharpening knives, its surface seems extremely smooth almost like porcelain, I started polishing one output device as shown, you can see that it removed more on the outer surface like it has a deepening in the centre where the die is mounted, it took 15 minutes to get the entire surface even, heat transfer has improved by some degrees actually.
Anybody else tried this approach?

Hi, sorry to sound dramatic, but I have been tending to an old ARC SP8 with your very generous help and been really close to completion with only a residual hum left to finish. Oh and it was sounding lovely today and then......

An oscillating volume/ a pop and loud buzzz. I muted the amp and then turned it off. It has done something similar in the past when I decided to get it repaired, and it came back with errr... hum and hiss. It also did the same a few weeks back when I plugged in a friend's CD player, I had just assumed it was some crazy inept cable + socket management on my part and ignored it.

I have not turned it on again, and wanted some advice before I do.

Is there a protocol to minimise the potential damage of what seems such a dramatic problem by turning it on to investigate?

Earlier today in my search for hum I checked all the obvious voltages and it was apparently spot on (or very near)

Thoughts?

😕

Diy Audio has just closed (in review) another of the threads over cables.
I was about to post this there, but I didn't arrive on time.
I hope you are interested and / or it is a "ground wire", just my two cents.

Speaker Cables: Can You Hear the Difference? | Sound & Vision

I liked the allegory of the basket with the serpent in a hypnotic trance ........

I am a fan to british amplifiers. Onix and Tony Brady. Exposure and John Farlowe.I d like to know who created qed amplifiers like the a240sa or the 270.

Is it possible to have a contact with the engineer who created led amplifiers ?

I have this power supply that would be a decent test supply for someone starting a small work bench or needs a cheap supply.

5V @ 2.2 Amps
12V @ 1.5 Amps

Shipping from 17404.

$20 OBO plus shipping

Just finished the simple push pull great sounding amp. Matching it with the Ariel 5b speakers (found drivers on eBay must be from the 90’s) Built the SPP years back. Cannot beat tube lab thanks for the great product

I have a pair of Electronic R-core 300VA 230V primary 2x 21v secondary that I plan use in Peter Daniels LM3875 monoblocks.

I understand for larger toroids it is a good idea to use inrush/soft start protection. Does the same apply for R-core transformers?

I have Sjostrom SST03 soft start modules that I could use but if not necessary would hold them for another project.

Thanks

I am looking for a fast low impedance single supply 45v regulator PCB. I like the dadod's but it is dual. Any proposition?

I just picked up a Dual 1019, while checking it out I found the cartridge holder siliconed to the tonearm shell mount the ear is broken off, I ordered a holder TK 12 from a ebay seller bestaudio, as I had read that the other ebay sellers holder is not great, bestaudios does not have the relief cut for the release arm, so I will have to modify with a die grinder. caveat emptor! I still have to clean and lube, looking @ putting a Nagaoka mp110, Grado Blue 3 or a Ortofon 2M red cart on it, the Shure Realistic R1000EDT will get an after market stylus for 78s.

hello,
i'm building a medium sized PA and im looking for the best compression driver/horn combo, to play everything above 700Hz (probably 1.4"). i'm aiming for 60x40 coverage angle, so heres the options i found while researching:

horn:

RCF HF64

eminence H14EA

SB Audience H280

P-Audio PH-305

compression drivers: (i know theres some really nice coax compression drivers, but i'd like the price for the comp to be max 300€)

SB Audience Bianco 75-CD-T

FAITAL HF140/ HF1440

18Sound ND1460

BMS, B&C...


i think the horns will all sound similar, im more worried about the compression drivers.... anyone have experience with the ones listed above? or am i missing any? which one is best (max ~300€ )??

cheers, lisette

Can anyone tell me how many Class A watts I have if my AB amp is rated 80 watts but draws 125 watts from the wall at idle? Is there an easy equation for this? Thanks in advance.

Hi there, Philippe From Montreal here.
Built a pair of full range speakers last summer using Audio Nirvana 10" ferrites.
Driving them with a very old SIMA integrated from 1994 that needs recapping.
Ordered the parts to build a tube 6BQ5 SE amp.
Have been reading a lot since the last 2 months about tube amps and would like to thank all of you for your contribution to this site; it is very informative.

Have a question about tube amp cooling but am not sure in which topic to post it. mind if I do it here?

Am thinking about using small fans to cool my amp. I currently have 1.5" fans I'd like to mount on the back panel of the amp, left side. Under the mains transformer. They are 12v fans, but I'd run them on 5v or 6.3v to keep the noise down. Would let the air from the fans exit through holes surrounding the tubes, which would be mounted on the front right side of the amp. The flowing air would carry the heat from the inside of the casing out through the holes surround the tube sockets, which would the help control the tube temperature by creating air circulation around them.

Do you think the fans would induce electromagnetic hum in the audio circuits, which would mainly be routed on the right side of the amp, away from the fans, mains, heater wiring, and HV, which would be mostly on the left side?

Hi friends
I'm—again—struggling with details and aesthetics. This time it's the switch.
Bathing in the sea of variations @ mouser, Distrelec etc., but there's nothing I really like.
I'll probably end up with a switch without "frontend"—requiring a self-made toggle of sorts, but still haven't decided on the function: Push-button, rocker-switch, rotary?

My fantasies are:
- Oversized "long stroke" pushbutton — inexistent?
- Rockerswitch: making a part of the frontplate the switch...
- rotary: Is there a switch that triggers 90°, that could be rotated endlessly? (not back and forth, but on-off-on-off-on etc. in one direction...

Could I get some directions, parts, techniques?
many thanks!
david

My room is 16' by 43' so pretty large, but I would be mostly sitting only 10-12 feet away from the speakers. I've never built a speaker cabinet before, but had looked a lot at the frugal horn stuff like 5 years ago. I have no issue with cutting weird angles and stuff since I have been woodworking for over a decade. I like the Kirishima plans from frugal horn. Is there a full range driver priced like the FE206En or other enclosures I should look at? Thanks!

How many here have been successful in using DimDim.s HiFiDuino Pro project?

TFT HiFiDuino Pro Project | Dimdim's Blog

I would like to use this to control my BIII Pro SE but I don't need the input select or volume control. I wanted to see if anyone has set it up and added or removed features.

Idea for full symmetrical amplifier...

Hi all, I don't often visit here unless I need something😱. Thank goodness for the depth and breadth of our membership and their expertise, not to mention their patience.

I looked around for practical suggestions and projects on the topic but haven't found much here on the forum, other than theoretical discussion of design, rather than actual device noise problems. We are facing, if not already struggling, with a shrinking supply of genuine new production, reliable to specified quality, thru-hole semis for the more critical areas in low signal and line-level audio. At affordable prices/quantities, we are left with only a few complementary types, such as KSC1845/A992, BC550/560, 546/556 that meet most of our needs but for how long and at what prices in the future?

On the other hand, we are swamped with cheap copies, fakes and even some good BJTs too, out there but many are what I'd call popular types from 40 or more years ago - good enough for many general applications but doubtful and variable quality for audio. So what I'd like, is a simple amplifier that is set up for a direct audio test of small signal transistors, with a test socket, small loudspeaker on a baffle and maybe another socket for a DMM with bargraph scale to aid recording the results, as necessary.

We can do that pretty easily, even on a breadboard but for a more permanent arrangement, I hope to use FR4 matrix board and use the DUT like a buffer amplifier before an opamp, followed by a a small chipamp or perhaps just a low-power chipamp for both, such as LM386, TDA2822, TDA2030 and so on.

The question is; in what circuit, with what input arrangement, impedance, gain, bias etc. do we operate the transistor? It has to give a reasonable representation of how the transistor will sound in a typically sensitive application and that means, I think, the dominant popcorn and hiss noise of the input stage transistor, as a LTP or singleton.

I recently watched a video where a DIY had adapted his unstably high gain stomp-box amplifier and fitted it with a socket for the DUT - no circuit details. He was plugging and testing transistors at a great rate, with very obvious differences between individual, new transistors from apparently, the same lot. I was convinced that there would be useful results with this simple technique if applied to audio amplifiers too, given that many of us are tempted to use cheap semis and this test at least tells us just how bad the idea probably was

I'm really only interested here in qualitative testing because it goes without saying that it's quite appropriate for audio, with respect to SNR. Any support, suggestions for the test circuit, comments etc?

Hey to everyone.

I burned all my mosfets when putting amp on heatsink without isolating tape. So i replaced my irfp244 mosfets and turned on the amp, and when i try to play some music the sound is not like a class amp. So i desoldered my irfp9610 and measured they are also dead. I solder new ones and try to play music again and its a little better than before but not good at all. And the mosfets irfp244 are cold as ice after 20min of running time. Maybe any ideas what can be wrong?

Hi All,

After years of working flowless my F5 plays on both channels but on one side the transistors are staying cold (not ever warm)
I'm getting .59 volts across R12

Any ideas what this could be?

Thank you all,
IK

This is my first post so I am expecting someone to point out that I have already blundered.... but here goes:

I think I understand that destructive interference occurs in the mid frequencies as a result of bipolar speaker configuration. I remember reading something Planet_10 said: that constructive interference is less likely to occur than destructive: that dips are more common than peaks with this set-up, and that dips in the frequency response are less noticeable than are peaks.
Is this correct? And if so, why is it the case? I would assume that the interference would occur in equal proportions.
I also read that a lenticular baffle could help minimize this consequence of bipole design, and that a baffle which is wider than the distance between the drivers helps improve response by moving the band in which the comb-filtering occurs.
Can anyone dispel any of these misconceptions, or otherwise guide me toward the appropriate reading material? I would love to read about bipole speakers!
Thank you diyaudio community!

Greetings,


a couple of months ago I made a great found in the attic of my parents house. A cyrus two issue 07 and two mission loudspeakers. Asking my dad who they belong to, he told me he hasnt turned them on in twenty years and he was happy I wanted to make use of them again.
After a couple of test runs and a new alps blue poty(information received in this great forum), I had the system up and running pretty nicely.

Unfortunatly I wouldnt be writing this thread, if everything was still working fine. After having some friends visit for a weekend and using the system intensivly in the living room. When I moved the speakers back to my room, not thinking straight i plugged both sides of the output cable into ground of the right speaker...
I shorted the circuit. Just had the look at the amp. The upper fuse FS2 is blown, i am guessing thats F3.15A. Didnt see any other anomalies on the critical transistors and components of the protection circuit.



I'm not sure wether I should just replace the fuse and hope for the rest to be intact or if I have to take further percautions to make sure I dont break anything else when putting in a new fuse.
In the first case, where can I get an adequate replacement fuse?



Hoping for advice from some more experienced base addicts.

Hi guys,
Some time ago I've bought a classe DR10 that needed some TLC (mostly recap), haven't listened to it and just dropped it off at a service shop, they found out the amp wouldn't engage(soft start section does work) unless it was linked to another component, otherwise it was missing ground connection.
He has somehow fixed it but we are still puzzled - how, why? 😕 I thought about the bridge mode switch but he told me that's not the reason.
He inspected the board and found no missing wires or wires dangling loose. We have a 2-wire 230V installation.

Is this something common with old Classe's?

Hi all!! Here's a strange on; I realize amps can & have been repurposed with strange & cool results, so has anyone ever thought of, or used a Dynaco ST-70 stereo amp for a guitar platform? I assume one could use a stereo guitar preamp of sorts? I mean, guys use Macs & other monster amps for their rock rigs, so I'm just curious..
Stay safe, Be well all~

This is a new thread that has been spun off from here http://www.diyaudio.com/forums/analogue-source/303389-mechanical-resonance-mms-32.html#post5115798 to discuss the measurement, analysis and interpretation of turntable platter speed and stability, with the end goal of understanding it more and the fixes for it when needed. The Dr Feickert test records and apps have made measurements a lot more accessible, but the presentation and analysis part has been missing. For example Fremer always posts Feickert output on his reviews (e.g. https://www.analogplanet.com/content/technics-direct-drive-sl-1200g-turntable) but you can see that they heavily filter the measurement, throwing away a lot of useful information (and the reviewer wouldn't know what to do with that information anyway).

Member Luckythedog has taken this up a couple of notches by plotting the speed on a polar chart, so you can see speed variation on a rotation by rotation basis. This immediately gives useful additional information you can use to work out where the speed changes might be coming from.

I should cover on this post why this all matters, after all we are talking subsonic effects in the most case. The reason it matters, along with record eccentricity and cart-arm resonances is that you are frequency modulating the wanted signal. Unless you are chasing a 'phat' analog sound this is something that it's worth trying to minimise.

Floor open for discussion

I just got a pair of ATC SCM40's very cheap but they lack power.
I'm using bridge Anaview AMS-0100 to run my other speakers, and i'm extremly happy about the sound! If it was possible I would use a pair of brigde AMS-1000, but since Anaview don't make the amps any longer this is not posible.

I would like at least 1000w of power, so far i'm happy with my Anaview and also my 3E audio 3255 but I need more power- What do you recommend me to look after?

Best regards
Johan the noob 🙂

Hi

noob her

Going to try to build a First watt F6. does this lists locks alright, or are some thing wrong?

nel progetto di elektor del PA300 tra il piedino 5 ed 8 di IC1 viene collegato un condensatore da 33p denominato C9. qualcuno mi sa dire il motivo di questa scelta circuitale? vorrei realizzare il progetto sostituendo NE5534 con un OPA627 oppure con un OPA604 in quanto per le mie orecchie NE5534 è troppo freddo in termini di resa sonora. un grazie in anticipo a chi risponderà a questa mia domanda. ciao allego il circuito elettrico

in the draft elektor of PA300 between the leg 5 and 8 of IC1 it is connected to a capacitor 33p called C9. someone can tell me why this circuit choice? I would like to implement the project by replacing NE5534 with OPA627 or with a OPA604 as for my NE5534 ears is too cold in terms of sound. thanks in advance to those who will respond to my question. Hello Enclose the electrical circuit

Here is the decision I am facing and would appreciate your collective wisdom.
My speakers will be a two-way system with a horn tweeter and a 15 inch woofer in a vented box. The horn will be driven by a Pass DIY (First Watt) F5. A separate amp will be used for the woofer. The woofer is only about 92 dB efficient and will need more wattage (100 - 200 Watts).

My choices are narrowing on the woofer amp.
1) Use an Adcom GFA-555 ii amp (at least 25 years old & stashed in a closet). I would spend about $100-200 refreshing the capacitors (especially the big ones in the power supply). The amp is old but it is working. The bias is fine, there is negligible DC offset, but there are some on/off thumps and noises. So it is a working amplifier showing some signs of age, but I have always loved the way it sounds, especially in the bass regions.

2) Use an old case/heatsinks from a gutted Adcom GFA-545 (stashed in the garage) and build a Pass "AB100"

3) Use an old case/heatsinks from a gutted Adcom GFA-545 (stashed in the garage) and build a Honey Badger.

The costs are all close enough to one another (with some scrounging on the transformer and power supply parts). So cost is not a deciding factor.

Are there any other choices? Note: tubes are out, chip amps are out, anything less than about 100Watts is out, the power requirement also probably prevent any reasonable Class A amps. Also, I am a cheap son of a gun and also an avid DIYer that likes to learn a bit in the process (I have some experience with electronic projects). I am interested in your comments.

Thanks in advance,
-Tom

Hi guys,

some time ago i bought this Onkyo TA-2600 3-head cassette deck.
I'm in the process of adjusting it according to the service manual.
Attached is the page with the adjustments (please right-click > open in an new tab for full image view).

The adjustments consist of 8 steps to be executed with that order (1 to 8).
I have successfully completed steps 1 to 4. I'm stuck with some terminology and questions about steps 5 to 8...

Step 5. Bias Trap
In the "Test Tape" column it says METAL TAPE, i guess it means to use a blank metal tape for this test. However in the "Line Input" column there is no input suggested at all.
So, how should this step be completed? Just put a blank metal tape in there and hit the RECORD button then proceed with the adjustment?
If so, where the Input Level control knob of the deck should be set to?

Step 6. HX-PRO
In "Remarks" column it states: "R-467 R-468 counter clock wise" (those are potentiometers on the circuit board)
I don't get it, should those potentiometers turned all the way to the left (counterclockwise) before the adjustment begins?

Step 7. Bias current
In the last column of this test, called "Remarks" it mentions "Input VR Maximum" . What does that mean? Is it related to the Input Level control knob?

Step 8. Record level
Here i guess i need to feed the RCA inputs of the deck with 1KHz sine wave signal and begin with the adjustment.
But in column "Test tape" it does not mention anything. Shouldn't I record the signal to a tape in order to compare Record and PB levels?
Also, again in column "Remarks" , it says "Input VR maximum" which i don't know where it is referring to...

Any help ?

Hi,
Anybody knows what is the different in those two types of NFB?
What are the advantages of putting NFB ground capacitor in the position A?

I saw that NFB in some cassette decks playback amplifier and wonder why they put capacitor at that position.

Thanks in advance for answers!

The private message automatic addressing does not work when forwarding one message.

W10, Firefox 83.0 (64 bit).

Can anyone explain how is this one considered a dual mono amplifier?

I have this JL Audio 500/5 Rev 1 it plays on rear and sub. However it doesn't play on Front left or right. Moved selector switches and many combinations to no effect. All LED's on the boards are lit. I did clean all the switches before I got the rear and subs to play.

There are no shorted or open FET's. What am I missing?

I found this article interesting as it shows measurement to try to explain the differences in speaker cables.

The “Sound” of Speaker Cables: an Analysis | PS Audio

Hello everyone! I am a first time poster, but have been appreciating this forum's knowledge and information for sometime.


I have a problem with my Crown DC300A amp. The IOC lights have started to come on when I have the channel set to twelve o'clock or higher. When initially turned on, the audio is audibly very distorted, but then becomes less distorted with time. It never fully goes away and IOC lights continue to flicker with the audio.


Before, the IOC lights would come on only if I was feeding audio to the amp while I powered it off. I understand this behavior is normal? It also did not have audible distortion before on power up at all. It immediately sounded correct and the IOC lights did not come on. I have had the amp for about 5 years.


Does anyone have any suggestions on how to start repairing it? I have a little experience with minor repair, but if it is really involved, I might send it out. Thanks!

hey guys!

i just got my hands on a spoilt cyrus one int amp. from what i've checked, the output transistors have given up. the originals are buv28, but i cant seem to get them from my local retailers. i have been considering getting the BD711 to take its place, with alittle more current and power dissipation abilities i think it would be better off.

i only face one problem, i did try swapping in a pair of 3055s and the played for about a minute before resigning to the grave. i suspect the HFE is too high thus drawing too much current. i was hoping to lower the Iq but there isnt a pot to do that.

i intend to replace the lower resistor in the vbe multiplier with a 1k pot to see how it goes.

is this sensible?

another thing, i was thinking of scrapping the original supply altogether for a psx-lookalike. from what i gather, all i need to do is remove the fuses that connect the original psu to the output devices and add another one. the question here is what voltage does the supply have to be? the markings on the PCB say +/-40v, but the buv28 would not be able to that kinda trashing especially with the increased current that can be drawn with the new supply.

there are holes in the pcb for a larger output device. can anyone help me out in locating a device that would be able to take that added power or would the bd711s do.

thanks a million!