I recently acquired some Tannoy parts,nameplate type 220,I tried to search infos about this amp and found none.Anyone could give me some clues about this amp?
The transformer I circled is for what pupose?transformer one side connected to the variable pot,the other side connected to the grid of VR100 tube




Thanks!

Motivation
Traditional FM radio has its benefits- one of which is an unlimited supply of free music. With the advent of local radio stations that play a variery of music from the past and do't talk too much, listening to radio has become interesting again, at least for short periods of time.

A line-in will be needed as well, for an MP3 player or CD player or both.

Bluetooth is also a possibility.

Feasibility Testing
The feasibility of this project is already tested, using a transistor radio costing less than $10. The sound quality is fully acceptable, and considering that the radio uses an LM386 chip, albeit it bridged mono mode, sound quality is not expected to be an issue.


1) Satellite subwoofer home theatre system through headphone output

Sound quality - suprisingly good, though lacking bass. Distortion most probablt due to broken antenna.

2) Un-enclosed Radio Shack 6" 40-1011 woofer driver with sensitivity of 93 dB/W/m

Acceptable sound quality

3)Sony SS-G333ES speaker

Sony SS-G333ES on thevintageknob.org

These are large speakers, consisting of a 8" woofer, mid-range, and a high quality tweeter.

Sound quality was acceptable, something I could live with. Sound pressure levels at 1 metre was measured at 75dB/W/m at half volume with distortion attributable mainly to the FM reception. Connecting a long wire to the FM terminal cleared things up considerably.

All this from a transistor radio powered by 3 volts of batteries.

FM Section
The FM IC used on this little radio is a CD9088CB. Output is to one speaker although the headphone output seems to be stereo,

currently using PCM1702P DAC chips. is there any difference if I were to replaced it with PCM1702P-K chips?
kindly advise
tq

I have a number of old audio amps that I want to gut and use the PSU's to build Chipamps (gainclones, etc).
The problem is many of the old amp PSU's are higher than +/-50VDC and many chipamps can only handle +/-40 to 45VDC.
I also need 5+ amps.
Anyone have any simple circuits I could adapt, like with 3055's etc?
Thanks for any help,
-Rich-

I have a 5k:8 ohm SE output transformer rated 5 watts. According to WE data sheet for 300b I can get 6.2 watts @350volts, 50 ma. Clearly will not be using at maximum output all the time. Will occasionally surpassing the rated 5 watts do any lasting harm? Or am I going to melt a winding😱

I know these sorts of questions come up all the time and there is no easy answer...

I have a set of Australian Axis speakers - LS88 and LS28 and a matching centre. The high frequencies on the LS28 and LS88 have all but disappeared - which I attribute to the aging Tonegen tweeter (94L65DS-03HD; 442TND).

I believe these tweeters were used in many speakers through the ages.

There is even a thread on re-doping them (or a very similar model):
How to Re-Dope Snell Tonegen/Foster Tweeters (Model E, J, K; gens. I & II) | Audiokarma Home Audio Stereo Discussion Forums

In addition to the re-doping, there is also ferro fluid that may or may not need to be replaced depending on if or if it isn't in there. In any case, I'm not sure if I'm up to taking these apart.

Anyway, have been looking for a replacement - unfortunately they have an in between cut out diameter (~94mm) and the LS88 has an extra magnet glued to the back..

Any ideas?

Hi
My friend designed two regulator with very small size. He is willing to offer PCB sample to member on diyaudio forum.

Dual regulator : SIZE: 82mm X 59mm
Positive regulator : SIZE: 65mm X 41mm
Supply voltage range : 5V -- 80V

here are the pics of the regulators:
dual

positive


This is the PCB:
dual

positive


Schematic:
dual

positive


The mounting on chassis:



each member from DIYAUDIO can ask for one sample PCB(dual or positive). Because the different voltage has different BOM, please tell me output voltage you need. Only 20pcs of samples for each reg.

Applyer only pays the registered airmail shipping fee 3.00USD.
My email address: coffin@diyzone.net

cheers

Coffin

I think this qualifies for this forum. Here's a link to a description of an electrostatic driver with a graphene diaphragm:

nanotechweb

I haven't seen any reports of sheets of graphene big enough to make room-filling sound, though.

(Here's a Wikipedia link for those new to graphene: Graphene)

Few

I'm going to be helping someone put audio in a newly purchased home, and also want to do some projects in my own. Also, once I get past some personal stuff, I want to FINALLY make* some custom speakers and matching cabinets.

I've made some crude albeit scaled room sketches in PowerPoint, but that's not going to serve easily for 3D cabinets. And for rooms, I feel there must be something simpler. Once upon a time I used Google Sketch-Up, or are there better choices by now?


*Not myself, my detailed woodworking days are past. Any LA-area recommendations for cabinet makers (speakers and stereo cabinet, not kitchen ha ha) very welcomed.

Hello all

I have got an antique radio with a nice casing, and volume knob that I am thinking of repurposing.
I would like it to have a line-in, and a bluetooth function. Unfortunately the radio can only accommodate one speaker, and I think i will look for a 5.25 inch driver.

I want to power it with a suitable board. I found many, with the appropriate power, line in, and bluetooth, and volume control (which i intend to interface with the original knob).


Here is a good example of a board I'm considering


But these are all stereo. I am a little at a loss as to how best to convert to drive a single speaker. I see advice about combining the line-level signal using simple resistor Y-shaped configs, but not clear about how to combine a class D L/R output to mono.

Any tips would be greatly appreciated.

After lurking for a bit a looking at lots of designs, I've started cobbling together my own.

This is a class A buffer for low-voltage headphones, with no input or output capacitors (similar to the directly coupled B1 buffers in this forum).

This is intended to drive my Etymotics, which only need about 0.2V.

There are three "channels": right, left, and a virtual ground return.

The source follower is an IRF510, and the constant-current sink is my tweak on something jerluwoo posted in https://www.diyaudio.com/forums/sol...ource-ccs-audio-applications-post4785961.html

It seems to simulate fairly well 🙂

Haven't actually built it yet, that's next 😀

This is my first "real" attempt at making an amp, so any and all feedback is welcome!

Hello

This thread is the continuation of a cartoon that started here:


Vintage JBL for subwofer

I transcribe the text of my notes:

DEFINITIVE DECISION :
CORNERS !
I will use this two furniture, the white will be for the box and the red for the front panel.

Box:
Prism
Volume 300 liters gross
Design: sealed
QTC: 0.550
Perfect transients, although less SPL, this is compensated with a gain of + 3 db in each box when increasing to this volume ..
So for the same SPL will need half the power (watts)

These pieces of furniture have been a gift from a friend who did not use them anymore.

They serve ? he asked me .....

The next day they were in the hall, WAF asked where we would take the dog for a walk, for the same place that we will enter and leave, I answered, or is not he another member of the family?

The prism (irregular) will be 0.50x0.50x0.70, and the height of the box of 1.40 meters.

Soon I will attach the results of the simulations with WinIsd

Ohhh, I will have to make many gifts (and many invitations to go out to dinner) to my wife, these monsters are not easy to accept in a living room ....
I am a lucky man, yes sir ! 😉

My latest diy preamp adventure. -/+ 24v Linear Supply. Sparkoslabs regulators. LSK489 for the jfet’s. 6 layer PCB (s/g/p/p/g/s). Startup / shutdown muting.

Balanced -> LL1676(1:2) -> jfet follower -> 10k ladder -> jfet follower -> dc blocking cap -> RCA

I will post measurements soon.. the in/out are flipped on the case.

Hello everyone,

I am building a project with a DF player and a GF1002 (based on PAM8403). The problem I have right now is that by pressing the play button on the DF player, there is no sound, however the GF1002's IC is heating up. I have attached my current wiring diagram.

This scheme worked before I hooked everything on a PCB, which probably have destroyed my previous GF1002 (+ and - were shorted) - it also heated up.

However now I have brand new both DF player and the GF 1002. When I connect only 1 speaker to DF player (to pins SPK1 and SPK2), it works.

What have I done wrong?

Hi,
According to TAS5558 datasheet:

The TAS5558 supports volume control both by conventional digital gain/attenuation and by a combination of digital and analog gain/attenuation. Varying the H-bridge power-supply voltage performs the analog volume control function.The benefits of using power-supply volume control (PSVC) are reduced idle channel noise, improved signal resolution at low volumes, increased dynamic range,and reduced radio frequency emissions at reduced power levels.

Click to expand...

The TAS5558 also features power-supply-volume-control (PSVC), which improves dynamic range at lower power level and can be used as part of a Class G Power Supply when used with closed-loop PWM input power stages.

Click to expand...

I wonder is there any examples of Full Class D amps which implemented this (or similar) concept on volume control stage? I think this concept overcomes one of the big concerns in audio when used with full digital amps.

This project is about creating better enclosures for the 3.5 inch speaker drivers that came with my PC speaker system that was converted to an amplifer in this thread:

http://www.diyaudio.com/forums/chip-amps/283845-pc-speaker-electronics-amplifier-conversion.html

Removing the 3-inch speaker drivers and testing them externally yielded some interesting and encouraging results. Placing them in cardboard boxes generated a surprising level of clarity and some semblance of bass.

The speakers do sound better when 'liberated' from their enclosures. There are several reasons for this, as far as I am able to ascertain. The speaker grille probably cause a lot of diffraction, and also resonances. The box formed by the front of the speaker enclosure and the speaker box also causes some level of 'boxiness' and resonance.

I hope to design and build speaker enclosures for the speakers.
Specifications:

Impedance: 4 Ohms
Power Handing : 3 Watts
Size : 3 inches

Measurements:

Frequency response : 100Hz to 12,000 Hz (pure tone)
Max output : 75 dB at 1 metre

I am looking for a SPST tumbler (toggle) switch which has a long actuator/handle (at least 30 mm long).
When browsing the internet, I stumbled across a switch from APEM in its 600H series.
In that series APEM has also types with actuator lengths 30mm and 40mm. But looking for a supplier I cannot find that type.
Can somebody on this Forum help me with this problem.
It is in fact not important which manufacturer but as long as it can supply that 30mm actuator it is O.K.
In the attachments I show which type I mean.

SOLD

1x LL1650 Power Transformer, EUR 80 + shipping

2x LL1663PP OPT, EUR 110 + shipping

First come, first served.

Please post you interest in this thread and send PM afterwards.

Payment via PayPal only.

Hello,
I am investigating one problem with airplay streaming involved in signal chain. Longer story is here
Short story is that it began from shairport-sync issues. But i got same problems without shairport-sync involved.And that is just mind blowing. I played 20khz sine signal from mac to airport extreme latest version and firmware and got the same crackling sound due to dropouts about 384 samples lenght. I am out of ideas, so want to be more sure that not only me getting this. Anyone having apple at both ends could test this. Just generate 20khz sine over airplay to other apple end and see if you experiencing this. Why 20khz? Because this is the most easy way to find a problem if it exist. Make sine just below 0dbFs and play. Please play for 2minutes at least. The problem could take time to appear.
Anyone experiencing the same please let me know.

Thanks

I have Mission 770 with pretty sever scratches on the top ... any tips for getting them out - short of re-veneering, which I'll not do

Pictures show after light sanding with 600 grit to remove high spots, light soft pencil scribbled to identify "layer", light sanding with 320 grit to remove pencils marks - damp wipe to remove sanding dust. Still looks like hell.

While doing some experiments on my speaker, I placed a piece of plywood in the back of the enclosure behind the woofer at a 45 angle pointing upwards:



That didn't really change the output of the woofer, which was my original goal, but I discovered that it significantly reduced (smeared) a 850Hz peak I had in the port output.
When I flipped this reflector to point to the bottom of the enclosure, that effect was gone and the peak came back.
I also tried putting a piece of high density rockwool in the middle of the enclosure behind the woofer, and the effect was kinda midway between the reflector and no reflector.
(see attached measurements)

As far as I understand, the reflector changes the path of the wave from the back of the woofer, shifting the resonances to different frequencies, and overall, scatters it around the enclosure.
I'd love to hear your thoughts and explanations, maybe there's a better/easier/more proper way to achieve this?
Also, if you know any good articles on how to deal with the sound inside the enclosure, please share. There is plenty information about stuffing but I didn't find much about the cabinet shape, construction, effects of slanted walls etc.

I found a vendor on ebay for SJEP120R100.
I am not posting the link here for the ad is easy enough to find on ebay.
Does anybody have any experience? Are these the real deal?
They are HELLA-expensive!

Dear people from Diyaudio,

I have struggled quite a bit before trying to solve my issue with the help form this forum. I play with a pair of wonderful mission 717's with a bit of an upgraded cross-over. After modifying my amplifier I heard an issue in my speakers. Both have a slightly different version Audax Hd100 tweeter. To solve the problem I bought the tweeter known as the "Direct replacement for...". After measuring I deal with a +/- 6dB difference. The man who sold me the tweeter kindly helped me and we measured an L-pad for the tweeter. Sadly enough just an L-pad doesn't solve my problem.

To sketch the situation at this point, the original crossover is as following:
Low pass: 1,6mH coil in series.
High pass: 6,8uF capacitor in series, 0,20mH paralel.

Simple, yet effective.
The current situation follows this + a 2,7 ohm resistor series, 5,6 ohm resistor paralel. With this impedance making it a 5,8db attenuation.

I can't honestly say that I feel like I need this or that, it's just not 'there' yet, and I'd love to get some suggestions. I made my filter external so I am able to 'play around with it'.

Hope someone can put my tweeter on the right track, I can feel it's 'almost there'....

Hi all. I'm planning a couple of builds and need to get a few transmitting tubes. Figured I'd check here before going to one of the online marketplaces. Especially interested in 845/GM70, but would consider others. I'd rather keep the $ in the community as well as not have to worry as much about breakage during shipping. Thanks much!

Loren

Hi,


I am lost in the uderstanding of group delay and also on how to choose the inductance characteritics of a bass driver.


I believe to know a coil for a low pass is adding a lot more of inductance that the driver has itself at those low frequencies. How much is it important in the choice of the bass driver please ?


What about a 8" having a Le of 0.2 uH like modern drivers with low efficienty and trade offs with older design with maybe 0.5 to 1 uH ?


My understanding is the lowest inductance gives the best group delay or am I mixing the concepts, i.e. missunderstanding the thing ?


I especially asking myself what Le range should be preferabily chosen when we need to pick up a mid bass drivers, these 6" to 8" drivers that are asked to make 50 hz as 800 hz ??? Is there a threshold where we should don't care anymore cause too much difficult to manage below a limit ? For instance 100 hz or else at seing for instance some waerfall in the bass areas ?!



How much should I care of the inductance in the datasheet, then in the coil filter for a first order low pass, please ?


Sorry if I am mixing up the thing too much btw...


Many thanks if you could beginn to enlight me...or give me simple path to follow fon howw to consider the Le of a bass driver.

Looking for V5, including manuals and key. Please contact if you have to sell.

I've been using 4P1L as PP driver in my GM70 PP amplifier and like the sound. I used it in place of 46 as they are hard to get. The 4P1L is transformer coupled to the GM70.

As usual the 4P1L is very microphonic and that is beginning to concern me. I'm not entirely sure if it makes a difference but if the music is loud and cut off suddenly (lifting the cartridge off the record) a ringing can be heard that fades out; like a small bell.

I'm looking for suggestions for an alternative that is relatively easy to get, not too expensive. Preferably directly heated but I might have to concede on that.

any advice for table usb microscope in order to solder surface parts or take pictures ?

become necessary with years

Used Harman Kardon Citation 16 lower front panel in very nice condition. Does not include power switch, neon indicators nor any other panel parts or hardware. Sells and ships to USA residents only. $99.00 plus shipping; PayPal with transaction fee added.

Used ADCOM GFA-585 power amplifier rear heatsink assembly pair in excellent condition. They do not include any semiconductor devices nor emitter resistors, and possibly other parts may be missing. Sells and ships to USA residents only. $125.00 plus shipping; PayPal with transaction fee.

As new Hammond RCBS1900317BK1 table top rack mount enclosure cabinet 2U height (3.5") high. Includes mounting clips and screws. Never used. May have some minor paint scuffs or flaws.

Sells and ships to USA residents only. $125.00 shipped; PayPal with transaction fee.

These speakers are the original ones as built by Troels - I was lucky enough to buy them off him directly as he was short on space and another one of his projects had to be moved on. Speakers will come with full build / crossover details.

UK buyer preferred, free delivery in England/Wales - dispatch outside of this possible but it might be costly.

Asking £3000 based on parts cost - good deal considering the kit price and sheer amount of baltic birch plywood used and huge amount of time Troels put into these.

They put most commercial speakers to shame - for example Spendor D7.2 at over £4K is nowhere near the performance of these (I have directly compared). I personally believe something like the Spendor classic range or ATC SCM100 SE would be a more comparable speaker.

These ones are fitted with the beryllium tweeter.

These have similar DNA as ‘The Loudspeaker’ but in a smaller package.

Original webpage for the build:Faital-3WC-15

Condition is mint.

As a happy Quad 63 listener, Dipole-DIY-er and fascinated by the AMT Mid-Tweeters ... why not face the challenge to mix that all together into yet another, this time slighty more experimental DIY project for me: A non-standard AMT with an electrostatic drive ...
ES_AMT_1.jpg

I started with the Idea of a folded AMT-curtain which would have some 4:1 depth-to-width ratio and would result in some sort of max. 4:1 compression ratio, if the membrane would perfectly move in parallel (which is not the case). I designed not much deeper, because of possible lambda/4-resonances.

The membrane is hold into it's curtain shape by carbon rods which are manteled by shrinking tube. These rods can rotate in the plexyglass holders so to allow some repartition of the membrane tension.
ES_AMT_4.jpg

On both sides of the array there is a V2A steel rod, letting stretch the membrane and slightly play with the tension. After the tension seems ok, the membrane has been further stretched with a hot air gun. The electrostatic load of the membrane is fed by one of these V2A rods.
ES_AMT_2.jpg

Each fold of the electrostatically charged membrane has on both sides 5 straight copper wires driving the audio signal to it. Because everything should be symmetric, in theory there would not be any lateral forces on these copper wires. Wirewise, a wire either pushes, or pulls both adjacent menbrane folds. All these 5-Wires-Arrays are alternatively fed by the high tension audio signal. One set is fed from the top, the other set with opposite polarity from the bottom. The distance from these arrays to the membrane is some 2mm, as everything is set up on a raster of 2.54mm.
ES_AMT_3.jpg

The transformers are 220V-5V types, which gives a theoretical ratio of 1:44 when inversely used. To archieve enough high Audio signal Voltage, two of them are used, totalling to a ratio of 1:88. In order to get some 4kV audio signal, the nominal 5V inputs of the transformers must be fed with some tenfold 45V...50V. Therefore, to avoid saturation of the iron core, this setup must not be fed with signals below the tenfold of the nominal 50Hz, e.g. not below 500Hz.
Transformers.jpg

The static high voltage is provided by a Cockcroft-Walton multiplyer, fed by a commercial inverter for cold cathode lighting, the latter outputting 700V ... 1100V / 5mA at a frequency of 30kHz. The diodes are 2kV/3A types, the capacitors are Wima MKS 2kV/100nF types. So at the end of the miltiplyer chaint there must approx. be some 4kV.
CockcroftWalton.jpg

So, hooking all together ... and driving it with an old faithful Yamaha AX 590.

Three different membranes have been measured. Twice (red/green) membranes cut out from an aluminium damped emergency blanket. KISS for the beginning, because it is a standarded and readily available (I know, I know, way too much conductivity ...). This kind of membrane material is very noisy by itself, very self-resonant, which leads to really messed-up acoustic results between 500Hz ... 5kHz, full of resonances. And also a huge and broad peaking above 10kHz. Because of these resonances, something completely different was used for a third attempt: Give it a chance with a self-adhesive aluminium ribbon, all along with it's protective PE-strip-off-layer (blue). This provides a nice self-damping sandwich membrane, a much smoother sweep audition, but an akward loss of SPL around 10kHz. So in the end, none of these two membranes were suitable. And I am reluctant to dive into self.made soap/graphite/magicmixtures coating of unobtainable membrane brands. Unless someone knows THE solution ...
Amplitude.png

Besides the resonances there was way too low SPL: 80dB, and when driving it louder, then the sparks went firing ... for the case of the safety blanket, each spark was evaporating some of the aluminium coating (sort of a nice self-limiting process, indeed). The foil itself was robust: The sparking was not punching a hole into the foil.
Membrane.jpg

So all in all the project is/was a fail until now. But it was fun, and I learned a lot about electrostatic LS. And I luckily am still alive, despite handling HT.

I have not given up completely, though: Maybe someone has some most welcomed constructive critics / remarks / hints?

B&K 1640 mobile equipment power supply in good condition with manual. Discrete linear regulated design provides 3 amp continuous current and voltage adjustable from approx 10 to 15 volts DC. Vintage 1980s. Has auto-reset overcurrent switch.

Sells and ships to USA residents only. We have closed our audio shop due to retirement. $40 plus shipping; PayPal with transaction fee added.

I have NOS genuine Analog Devices AD743KN (9) and AD745JN (11) for sale. The 743s will work well in ROTEL RQ-970BX phono preamp upgrade and the 745s are excellent for ADCOM GFP-565 preamplifier phono stage upgrade (along with required resistor and capacitor changes). These were sourced from an authorized USA distributor and have been long out of production. We have closed our audio service/upgrade shop due to retirement. $20 each plus shipping. PayPal with transaction fee added. Sells and ships to USA residents only.

Hello everyone. My name is Brad. I have been lurking around this site for many years(about 20). Back in my teenage years, I was really into home and car audio during the early to late 1990's. Now that I am a married homeowner, I have an interest in building a few projects for my house and as well as my cars. A lot has changed since the late 1990's, and I would like to catch up on the current technology. Back in the 1990's I was a huge Cerwin Vega fan, and I am currently a fan today. Going back 25 to 30 years ago, I remember amplifier power was quite expensive being between $2-$5 per watt. Today, I see that there are amps out there with a lot of power for significantly less money. I also see many new companies out there. I am glad to start posting, as I have so many questions since I was active building stereo systems over 20 years ago. Thank you Brad

Hello, does anyone here know what happened to the site of an Korean or Taiwanese Sub miniature tube headphone amp site ?

I visited the site last in 2013 but i cant find it anywhere anymore.
This guy made beautiful tube amps in, to me, impossibly small mint tins.

All battery operated.

I downloaded one project of his the "amp head micro" but even googling on that name or reverse picture lookup doesn't give any results.

If any one knows where to find more documentation that would be great.

Kind regards Oliver


His name is sijosae. Old site is "http://www.headphoneamp.co.kr/ftp/sijosae/Gallery/"

My Logitech Z-2300 unit suffers from an audible low frequency humming. My observations about the humming are as follows:

• The humming comes from both satellite speakers and the woofer speaker. Though I'd say the humming from the satellite speakers is slightly louder.
• The humming is independent from the volume setting on the control remote
• The humming is present with and without an audio source connected to the 3.5mm input
• When disconnecting the satellite speakers and the woofer speaker, the humming is no longer audible. Though I can hear a similar humming (same pitch) originating from the toroidal power transformer, but it is much less audible.
• The humming remains audible when only the woofer is connected (with satellite speakers not connected) and when only the satellites are connected (with woofer speaker not connected).
• The humming was also present in my previous home.

Upon researching this issue on google, the most probable culprit would seem to be a ground loop. Note that the unit does not have a ground terminal (it uses a two terminal plug). I've disconnected all other appliances in the room and connected the speaker set directly to the wall socket, but the humming still persisted. Nevertheless I have been unable to exclude a ground loop as the cause of the humming. Can a ground loop be a problem considering the device is not grounded to the mains? Perhaps the issue lies with the grounding inside the unit? Would this manifest itself as a humming tone?

Upon googling further, I found a common problem in the Z-2300 is a subpar mechanical joint of two ground wires. See Logitech Z-2300 subwoofer hum solved! | YourITronics. I replaced the mechanical joint with a soldered joint, but unfortunately this did not mitigate the humming.

I then spend some time measuring the power supply circuit of the Z-2300 with my DMM but I couldn't find anything suspicious: mains voltage appeared over the primary coil, the secondary was at 40.2V AC and I measured 54.2V DC after the bridge rectifier. Measuring the rails for the MOSFETs, my DMM reported an initially high ripple on the DC voltage but after a while the reading would stabilize to less than 1V (note this was with no outputs connected).

I then proceeded to try and de-solder the output caps on the bridge rectifier (in order to measure their capacitance, I don't own a ESR meter) but have been unable to desolder them due to all the epoxy on the PCB. As the two big caps still look in good condition in the pictures linked below, I'm doubting whether they are causing the humming.

The similarly between the humming from the transformer and from the speakers leads me to believe the transformer might be the culprit? While reading on transformer humming, I typically read about mechanical humming. In this case the humming from the transformer sounds more electrical though. Is there anything I can try to determine whether the transformer is the culprit? Unfortunately I don't have access to a bench power supply, I only have a DMM (though it can read capacitance and conductance).

Finally, can anyone suggest any further steps for troubleshooting the issue?

Link to imgur album.


edit: replaced images with link to imgur.

Looks like this is a "rare" amplifier? Not much information out there on it. I have been running it as my 3rd spare LOL.



Started doing a weird thing where there would sometimes be no audio, but if I turned the volume way up it would start to play for a while, then stop. Figured I'd open it up and see what's going on.


One of the MOSFET's (looks like the power supply section) let out the magic smoke. 2 more have bad solder joints. Seems simple enough, but I am not sure what is the correct part.



Silk screen on the board says T3055, Part itself is BUZ71A. T3055 is kind of generic, lots of parts come up. BUZ71A has some more specific results, but seems to be obsolete. Found one site that had STP16NF06 as an x-ref.



I understand it is risky buying parts on Ebay, but what about Amazon?? Or, best to stick with the reliable part houses (Mouser, Newark, etc.)



Looking for someone smarter than me with experience to suggest the best route for replacement part?



Thanks!

2 bags for sale or swap. VZ serie 50V

looking for LMT 30734060GAA and LMT 30734050GAA relay datasheets.

thanks

Hello,

Sadly, but I am selling my Paravicini The Head TX-4 MC step-up transformer. It is in very nice condition, with very small signs of usage, but considering it's age I would consider it perfect. I've been using it for many years with great pleasure and I hope it will get into good hands.

It's a legendary SUT with magnificent sound. According to my best knowledge only 200 units were made, this is No.28. They show up for sale very rarely so now it is your opportunity to get one.

Item is located in Budapest (Hungary) and I am happy to ship it globally. I will pack it very carefully.

Asking price: EUR 2.290 plus shipping

If you are interested, please send me a PM.

For sale is my Lyra Clavis D.C. cartridge rebuilt by ANA Mighty Sound in 2018. Since then it has been played only a few hours and it has been sitting in my drawer.
ANA Mighty Sound just recently checked it and they found everything perfect. Cartridge looks and plays as new.

Rebuild includes:
- silver coils
- Ogura PA stylus on boron cantilever
- new silicone damper

VTF: 18 mN
Coil impedance: 6,1 ohm
Tracking: 100 micron / 315Hz

As you can see it tracks better than when it was brand new.

Don't underrate this cartridge, with the rebuild its quality has been raised significantly, with the silver coils inow t plays in a much higher league.
Amazing 100 micron tracking ensures not to miss a note from the record.

Asking price: €790 including express international shipping.
I am also open to serious offers.

Photo shows actual item. You can buy with confidence, I am long time member on DIYAudio.

For sale is my Audio Tekne MC-6310 low impedance MC pickup. It has been rebuilt by Ana Mighty Sound and it sounds very lovely.

Rebuild includes:
- new coils made from silver wire
- new cantilever with Line Contact stylus
- new damper (silicone based)
- cleaning, alignment, testing, fine tuning

VTF: 20 mN
Tracking ability: 80 micron / 315Hz
Coil impedance: 3,4 ohm

Stereophile recommended components under phono cartridge category class A.
New price was around 4200 euros.

Asking price: €1450 including FedEx International Priority shipping.
I am also open to serious offers.

I have the photos of the rebuild and I am happy to share some with potential buyers.

will not use germanium transistors, so if they can make someone happy 🙂

• ASZ17
• ASZ18
• ASY80
• 2N526

for sale or swap

Hello,

I've got a pair of small fullarange satellites in a 2.1 system with some serious phase sifting in the low-mid treble region. The sats consist of the PS95 driver in a 2.8 liter box with a 14cm baffle without any passive filters, and a 8's sub for everything lower than 100hz. Take a look at the REW measurement ( dont mid the high bass output this is just how i like to hear my computer speakers with some extra bass) i am curious about the multiple phase shifts in the 1k-5k region. I dont notice something significant by ear, but maybe that's because i havent listened to a lot of speakers. The mesurment is taken form my ear high right in the middle of the speakers (which are about 1 meter apart and have a slight tilt inwards. Is this significant? what might be causing this?

Here is an idea of a tricolumn speaker using the f88 (or other small speaker). I've designing it using the specs from the paper "Now,a tricolumn- build this efficiente column spekear" by R. N.Baldock. Two questions:

1. How to model it with Hornresp? Simply use parabolic sections? There are some discontinuities in the interfaces between the 3 cylinders (one of them is not a cylinder)...

2. Or just go for it with a thumbnail calculation based on the resonance frequency (L=c/(4*f)) and taper ratio of 1/3, height of the inner tube d=2*L/3 (part 2 of the paper)?

Thanks.

Hello!
I recently acquired a Cyrus iii amplifier for cheap and was wondering if it's worth more than parts. I would really like to fix it but I'm not quite sure where's the problem. When I turn it on with the power switch in the back, amplifier displays different combination of leds (see attached pictures) almost every time and the front panel buttons or volume control aren't responsive. Power indicator shows green or both green and red at the same time. I guess that there is a communication problem between the chips in the front board (the one with the buttons). Can anyone confirm my suspicion? I've soldered and desoldered surface mount components before (no destroyed pcbs so far), so I'm willing to give it a try to repair the board.

Hi. I put a voltmeter across my tweeter and it read a fraction of a volt.

Why is it that people use 250v and 600v capacitors in the high pass filter when the actual voltage reading is so low. Why not just use a cap rated at a few volts and save money rather than paying extra for a 600volt cap when there is no need for it..

I have been using an Ipad for too many years and its time for a new one. I use it almost exclusively for internet use. Getting tired of rotten apples behaviour. Never tried anything else. What other brands are a good alternative? Pros and cons? Thanks for the help.

This is amp number 2

This one doesn’t power up

Here is what I get on the 3525

Pin 1:0.00
Pin 2:5.01
Pin 3:0.00
Pin 4:0.14
Pin 5:2.09
Pin 6:3.60
Pin 7:2.07
Pin 8:0.29
Pin 9:5.47
Pin 10:0.00
Pin 11:0.00
Pin 12:0.00
Pin 13:13.47
Pin 14:0:00
Pin 15:13.47
Pin 16:5.01

Finally: The Art of Electronics | Electronics for physicists | Cambridge University Press

Hi dear DIY colleagues!

I bought me a great vintage denon poa 2400 power amp and pra-1500 preamp.
Sounds nice but when i change the preamp by a newer denon that I still have (pma1055). Well, then i prefer the sound of the latter.
When listening to the pra1500 I experience listening fatigue and it’s like I’m really missing dynamics and the highs are really overly bright...

I didnt’t notice anything physically wrong with capacitors. So I bought me a cheap capacitor tester and started disassembling some capacitors (randomly). I measured the two biggest capacitors (right after the transformer), then some in the tonal circuit. But they all measure fine.

I could measure all, but first I would appreciate some feedback from you people.

Do older capacitors affect dynamics and tones?

Even if they measure fine, should i replace them? Consider their age: + 30 yrs old.

Could i be measuring wrong?

Maybe its just the sound of the preamp? Find this hard to believe though, cause the preamp Im using now is really low end. But sounds better.

One more thing: the transformer does have a hum. But still outputs a nice 23,6 volt.

Thanks for your thoughts on this one!

Ps: i attached the manual (part of) of the pra 1500

Gr

Willem

One thing I’ve never really looked into before and a topic I’m having a very hard time finding information about:

Are drivers that require smaller enclosures inherently better than ones that require larger enclosures? Vice versa? What is one sacrificing over the other?

Hello: I just acquired these drivers; any body have any info about them?
I was told they were used in a factory passive sub about mid 1990's vintage.
The person I got them from gave me no specs except for a piece of paper stating
cabinet volume of 4 cu ft. & a crude diagram of the port & it's internal distance
from the cabinet. No info as to where to put port front or back.
I'm going to try to attach some pictures.

...................... thanks

.................. Fred petersen

Hi
I am selling nr. 3 tubes 845 RCA nos, never powerd on.
All checks before shipping.
Send message if interested

Walter

It could not swing the voltage into a set of lousy Koss 250 ohm cans to play percussion at a good level. Trying to do the same with a Zhaolu DAC's headphone amp literally smoked the Zhaolu's amp section.

It distorts like hell and assume transistors - not the sub-minature tubes, are cooked.

Don't know the shipping - have to find a box - would guess under $10 first class in the US

$25 sans shipping.

If restored to proper working condition, I would not recommend use with high Z cans.

Schiit would not provide a schematic so one is on their own.

The power supply will not fit a "small" Priority box. The DAC and PS
of course would fit the "medium" Priority box but that's around $15.80.

The idea came from xrk971’s 10F/RS225 FAST thread.

I was looking at woofers I could get around here since the Daytons are not available locally, and shipping here is prohibitive.

A distributor with good pricing recently showed up for SBAcoustics, and it got me excited that I may find a suitable woofer, as I already had the Visaton B80 laying around.

Going through the SBA website is no joke! There are so many products, it’s easy to get confused.
I was going nuts trying to find a match to the RS225, then I stumbled onto their new 5x8” race track woofer.

It looked ok to try and I shared the idea on the 10F thread.

That’s when BYRTT pointed out that c-to-c using the 5x8 woofers and a small full range driver would be very interesting, and how about a MTM, or in this case WFW?

The data that BYRTT shared pushed me in that direction easily. Having played with XSim and the manufacturer’s curves, I thought it had great potential.

So, I contacted the distributor, and 2 days later, all 6 drivers showed at my door, COD for only $6 shipping cost! That’s service!

BTW, as a plug, this is the distributor in Taiwan, should anyone be interested. They are very nice, and they speak, or write, Chinese as well as English.

thlaudio web site pages

So, this will be a thread on how it will turn out in the end.
I have an idea, but I may change a few things along the way according to measurements, I’m not inflexible.

Shall we start?

So, as we already know, the woofers will be the 5”X 8” SB15SFCR39-8. Two of them per enclosures.
The enclosures will be sealed.

Inside, sandwiched between the 5x8s will be a 2½" SB65WBAC25-4. It will have a sealed space inside the enclosures. This driver has been reviewed as having a great dispersion and great high end reach… close to a tweeter.

These are BYRTT’s measurements of this driver, in FR and dispersion… pretty good!





MTM, or in they case WFW, improves the vertical polars, as more data shared by BYRTT showed here



After I build them an enclosure, I’ll first try a simple 1st order XO, but will probably settled on a more elaborate one later on…





I’m sure I forgot something, but this is the beginning, so, I’ll keep adding up.

European seller ideally as I'm based in UK.

nice - very little use since serviced by Monarchy. Ran it on my Klipschorns. DC offset: 0 volts left, 2 millivolt right.

$445 not including shipping (probably $70 or more UPS from WV to CA)

- could not locate its original box but will have sufficient XPS foam padding.

US Only. Paypal Only

Hey all,

I will be honest. I have been working with audio for many years, engineering source parameters as an ME, and I am taking a deep dive into building my ideal mastering main speakers.

No need to go into tons of detail in terms of driver specs etc too much. The plan is to use a 10" sub, 6" mid, and planar tweeter.

Many of my favorite designs use an MTM -type format, at least with the tweeter below the mid. Grimm LS1 and Stratus Gold come to mind.

Another thing I've noticed in the best presentations I've heard is having mirrored tweeters on the outside of the speaker. This seems to improve imaging as well, although in a different way than MTM.

I have a terribly inaccurate two-second mockup that shows two concepts for the design. Would love to hear people's opinions about what would perform better.

If anyone is interested in more aspects of the design, I'd be happy to share them. I just figure that I'm verbose enough as it is. haha

I'm looking for a simple 38 - 40v 150ma P/S built around an LM7824.

I thought a 15v Zener on the centre pin with an 8k2 from the o/p pin, to make sure the reg. is not starved, should jack it up to 39 volts as I have all the parts lying around.

But, the LM7824 is rated for a max i/p of 40v. - Am I correct in assuming this refers to the max i/p voltage between i/p & centre pin, & as long as it is below 40v here, it should be OK.

The total input voltage I'm feeding to it is about 46 volts which should leave about 31 volts between the i/p & centre pin.

Comments please.

I am not used to this type of layout, why are there 2pairs of mosfets on each rail that is connected in series with inductors?
First pair triggering the second or what?
I feel stupid!
Rail voltage +/- 118v

Yamaha yst sw1500 triggers protection

Recapping this but come across some 470uf 120v caps at positions 513/514 in the power supply and 401/402 between amp modules. Any reason these need to be 120v or will 100v work just as well?

Just wanted to see what people thought of this bloke on YouTube I am following
Was going to give it a try on my Marantz 2238 old receiver and a couple of Sansui amps
Is your Amplifier & Speakers Balanced Correctly, Stereo Channel Tune Up using Audacity, Hifi Vintage - YouTube

Rav.

Hey fellas,

Having recently been made redundant it may be time to downgrade some of my Hifi gear 🙁 First to go will be my DAC. It's a Trichord Pulsar DAC that I bought used a few years ago, although it cost £1400 back in 1994.

My thinking is to replace with a modern budget equivalent (CA DacMagic), which sells for around half the price of the Trichord on the used market (£150 vs £300) - I'll pocket the difference into savings.

Reading up the on the DacMagic's specs it looks as if DACs have come a long way the 15 or so year between them so I was hoping the audible difference will not be that great. Before selling it, curiosity has got the better of me and I've decided to see what is in the Trichord component wise to compare:





To my surprise there are two toroidal transformers housed inside the main DAC, as well as an external PSU!



Compared to the DacMagic, there are obviously far more quality component with regards to capacitors and power supplies, although the circuitry seems far simpler.To be expected, given their respective age gap of 16 years:

ImageShack® - Online Photo and Video Hosting

What do you guys reckon? The DacMagic has had plenty of praise since it's release I am hoping the far more advanced chipset/DAC chips will compensate for it's relatively cheaper output stage and wall-wart power supply...

Since there is a 15 year difference between the designs, this seems feasible to me, or am I dreaming?! Since the £150 saving I will get by "downgrading" is fairly modest, I don't want to do something I regret.

Thanks for any advice

MS just upgraded all four of my PCs (Win 10). Now RightMark analyzer crashes.😡

Purchased a bare bones Fusion 12 kit from DIYSG back in August 2020. Erich was able to provide me with a list of crossover parts but no photo or schematic of the crossover. My last email response from him was in August when he stated that he would provide some sort of assembly instructions for the crossovers. Have emailed several times since then but no response.



Wonder if anyone would be willing to share this information, privately of course. Would like to run this by Erich but I would not be asking for this if I were able to get in contact with him.


Not trying to be a pain, and I know Erich has been busy moving. My guess is he has not been able to come up with this info and is too busy to research it at present.


Any help would be appreciated
Charles Sedivy
csedivy22@gmail .com

Hello. I've recently received some Seas T18 coaxial drivers. I've quickly thrown them into some sealed enclosures I had which provide a qtc of between .5-.6 according to calculations. I am using them close the wall and one is near a corner in a fairly near-field apartment listening setup. With some very rough measurements and based on what I can find online I've dialed in some basic crossover options into my mindsp SHD and measured to ensure they sum to a fairly similar FR. This driver seems to allow for 1st order crossovers, Seas uses 2nd order for their Loki kit, and I noticed their minidsp active preset they provide for the Loki uses 4th order LR with some EQing to flatten FR further. So far they sound pretty good! It's my first time using coaxials and I'm enjoying the 'solidity' to the sound when moving my head. As I don't always sit in the same place on the sofa and often move around the room, I can def notice a more cohesive less phasey sound when not in the sweet spot which I'm enjoying.

What I'm trying to understand is, does using a coaxial fully removing lobbing issues associated with each crossover type? and if so is there any reason a 1st order would be recommended in this instance over a simple 2nd or passive/active 4th? I suppose it depends on if I stay active or go passive, I assume running active there's little reason to not just use steeper filters, and the only reason to not do so passively would be costs/complexity of crossover?

Goodmorning everyone,
I have 2 80's speakers from FBT, it's the Europe l1200
RCF L18p200n woofer + RCF n980 driver
yes, you got it right, a 2-way with 18 woofer
the sound is fantastic, vintage as I like it but the bass is few
the case is about 110 liters with two 150mm holes without tubes
simulating with bassbox I noticed that they aimed at the peak of 80hz sacrificing everything that comes first.
can anyone tell me if i can improve the bass by working only on the reflex ports?

A tube amp was given to me. I powered it up and the 4 rectifier tubes lit up, about 5 of the 12AU7 tubes lit up, and the longer slender tube by the choke flickered / stayed constant/flickered. I think I have a stereo integrated amp. Please see my images attached.

I searched in the vintage Hammond catalogue and came up with the following:

2 x Hammond 1626X OT's, 20 W each. "X" means chassis mount

1 x Hammond 710X T 110VA

1 x Hammond 1136X T 78VA

1 x Hammond 159ZC 06H 2000mA choke

The rectifier tubes are RCA 7027A tubes and the slender flickering tube I am not sure, the label reads 0A? .

Think this might be a project to spruce up modernize a bit. Since I am a novice in this hobby, I am looking for comments and recommendations.

Regards,
Myles

I have always built sealed subs; several reasons, but anyway, I have been looking into BP-4 alignments to reduce the mid base distortion mostly, and because I never did one. Anyway, I have a Dayton RS265 HD and a Dayton Titanic 10. Both good drivers for their size, reasonably low distortion, and work well sealed. Small, but I listen to music not insane loud special effects. They seem to model pretty well, but I do not know what a BP driver should be optimized for. Both have low EBP. Ports come out very long, but do-able. Do I want a low or high Qts for example?

So, wondering if there are suggestions for alternate drivers that are known to work well in BP-4. I need to pass 25 to 80 Hz. The Titanic comes out pretty good at about -3 dB within less than a dB of ripple. Excursion is within reason as long as I toss in a 20 Hz first order HP.

I looked into PRs as I have not dealt with them before. I see some advantages, but would need probably at least a 12, if not a pair of 10's. Costly. 4 inch port is coming out as 9 m/s but 42 inches long. I had a 3 on the Titanic years ago and it was horribly chuffing. I think it calculated at 17. So much for 1/10 Mach theory.

Just curious. They have a known pleasant sound no matter what is being used with them.

Hello 🙂

I have this plan of a diy audio interface. The goals are as follows:

1. USB connection
2. at least 1 instrument input (for guitar)
3. at least 1 output (for headphones)
4. 16bit/48K minimum
5. integrated preamp/headphone amp
6. preferably usb powered, but I might have a 9v transformer that I can use for a linear supply.

Initially I planned on taking a cm108 board and just hooking up an opamp buffer with a level control but while researching on some alternatives to that board because mine had a noise floor of like -60dB, I fell into the DIY audio hole. oops. The analog part should be fine, it's the digital part that I need some help with.

Now, my plan is to take a CM108 and wire in a PCM1802 ADC and PCM5102 DAC via I2S. I chose the combo as I feel like it has some potential to sound good. Is this a bad idea? I don't have much experience with digital audio. I tried researching for other DIY audio interfaces, but I'm a bit lost. I'm open to other options. budget would be approx $30 max.

I'm also looking at modding this, as it apparently sounds good and it also has an I2S input.
SA9023A + ES9018K2M USB portable DAC HIFI fever external amplifier audio card (i'm not buying from this site, only put here for reference)

The reason I'm doing this is because I don't have much money to get other boards or complete units as international shipping is way too expensive in my country (Philippines) and also because I want to get my feet wet in audio more. I'm not really interested in making full speaker setups.

Thank you so much, and apologies if there's something wrong as this is my first post.

Would this be good woofer for 3-way? I would use about 450 Hz crossover. What is 2,83V 1m sensitivity at 100 Hz?

Hello there, I'm trying to build a ported speaker box for 4 inch 16w sub. I don't know how to choose the dimensions. Also I don't have any other specifications of the driver. Can anyone please help?