Hello,

In a scenario where a darlington pair is built using a high-current low-beta device driven by a signal high-beta transistor, what is the recommendation for placement of the driver, close to the output device's heatsink or on the contrary farther away so it doesn't pick up heat from the high-current pass transistor? Logically the driver should thermally track the output device, since in a monolithic Darlington they are on the same die no? I also have observed that the darlington input drivers tend to be next to their output transistors in power amplifiers. Thermal issues causes and effects are still a bit fuzzy to me, I would appreciate an explanation of the thermal effects at play in such a situation.

Below is a tentative pcb layout where I put the driver (Q1, TO-92) inside the output's transistor (Q2) heatsink fins, the output device being on the other side of that heatsink. Note that this circuit is high voltage (200-400V).



As always, thanks for any insights. Regards,
- Joris

Once upon the dawn of car audio, there were 1/3 octave and parametric EQs, and a few rare time-based things. What options do I have today?
And, as a bonus question, can I get away with a stereo unit for EQing the fronts* only, and use lowpass and gain and maybe Punch EQ to adjust the bass?

There's a 2017 VW Alltrack I'm driving frequently now, want to up the system around the factory radio. The current ideas:
- Replace the fronts with a component set (Crutchfield shows both 5" and 6" models supposedly fit...?!?). Probably a high end Focal since we have their home speakers, and a friend's swap in a CR-V sounds really clear.

• Gonna have made a box to fit in the rear footwell right behind the driver's seat. Currently thinking a pair of Rockford** 8" in an opposed configuration for force canceling. Fb around 60, Q below 0.7, should sound tight.
• Some 4-channel Rockford** amp to power the fronts and the sub. The fader will thus control the sub level.

OK all beautiful hopefully. BUT surely I will not be so lucky as to achieve perfectly flat response, hence the question above...


*Disconnect the rear speakers, I don't listen to rear stereo at home, screw this.
**why RF? My old business partner can get me all this free.

So I’m confused, and hoping someone can help enlighten me over what I can find on line.

Everywhere I look I get people saying if I’m building speakers, to only use a single woofer and a single tweeter… otherwise you get comb filtering.

Yet, every where I look- even super high end $100k speakers… there are multiple same size woofers in the floor standing cabinets.

So why?

How have they solved the issue?

:frustrated:

Thanks all

(2) CDT500/64k Renkus Heinz. Pulled from the CT5/64k speaker pair, same combo as what fits in the CDT-1 without bracket and rear weather protection cup (drivers are sealed anyway, so the same performance). If you want point source from a HUGE 24" x 24" horn exit! 103db Pattern Control down to 500hz. Reminds me of the original Lambda Unity or Danley Synergy. Too large for my application, which is why I am selling. Sound great!

$500 per horn w/driver and crossover included or $900 for the pair (w/drivers and both crossovers). Buyer pays actual shipping cost (24x24x24 box, 30lbs per drive - I may be able to fit everything into one box)

Photos show the actual horns, no cracks and output show they both pass rub&buzz test on Dayton DATS3 woofer tester (horn disconnected during test).

Shipped from Nashville, TN area. My Ebay name is "daus300b". PayPal. PM me if interested.




More info: https://www.renkus-heinz.com/product_detail/cdt500/

CDT500 series horns feature Complex Conic waveguide technology
and the unique Renkus-Heinz CDT-1L CoEntrant mid/high frequency
driver. They offer smooth pattern control down to 500 Hz along with
tonal quality unattainable with conventional high frequency drivers.


CoEntrant Topology (U.S. Pat. 5,526,456)
Integrates a midrange cone and HF compression driver into a true point source with inherent time-alignment.

Complex Conic: The Next Step in Horn Evolution
Complex Conic horns provide superior pattern control and more natural sound; may be rotated 90º.

High-Frequency Compression Driver
Provides crystal clear highs from 1800 Hz to18 kHz.

Eight-Inch Mid-Range Cone Transducer
Easily extends response down to 350 Hz with low distortion.

Weather Resistant Design
Sealed driver enclosure and weather resistant cone offer maximum protection from the elements.

Choice of Coverage Patterns
Choose between 90º by 40º, 60º by 40º , 60º by 60º and long throw 40º by 40º designs

Choice of Models
The CDT500-64K is a medium throw horn with a 60º by 40º coverage pattern.
The CDT500-94K is a medium throw horn with a 90º by 40º coverage pattern.
The CDT500-44K features long throw 40º by 40º dispersion.
The CDT500-66K features 60º by 60º coverage, ideal for overhead distributed systems used in large high ceiling areas.

All four models provide tight pattern control down to 500 Hz and below. They come complete with a built-in crossover and a weather resistant housing for the driver/crossover network.

Hello I have a DVC subwoofer that has 2.6ohm coils and have been searching for some cheap chip amps that could power it. I'm not looking to spend a lot on it because it's just an extra sub for my garage. It it were a dual 4 ohm sub it would make life much easier but I'm trying to work with what I have. Would it be possible to use an amp like the Aiyima A07 and hook 1 voice coil to each channel? I know it's below the recommended ohms but would it work if I used a lower voltage power supply with more amps? I have a SMPS that is adjustable from 1v-48v with 10amps.

After using a 90’s vintage Yamaha power amp (MX630) with my Chinese DAC (SMSL D300) for a spell, I got to thinking maybe I should upgrade to a new modern amplifier. I took home a demo unit from a local audio store. The amp was a Hegel H190. Retails for around $4500 Canadian. I used an optical cable splitter and fed it with the same signal as my SMSL DAC connected to the old Yamaha. The digital source was a WiiM pro streaming CD quality from TIDAL. I also had a three way amp/speaker switch so I could switch amps on the fly. I adjusted volume to the same level in both using an dB meter on my iPhone.
After extensive listening and switching back and forth, neither I, my wife nor my 24 year old son could hear any difference. If I wanted to guess, the Hegel may have been a bit fuller in the upper bass, but if it was it was marginal. Soundstage and imaging were indistinguishable.
For speakers I was using my DIY Seas Idunn two way bass reflex bookshelves. I have listened to these side by side with Focals and Martin Logan’s and they hold their own.
My amp system cost $600. $500 for the DAC, $100 for the used amp. Far cry from $4500. Needless to say I will not be keeping the Hegel.
Goes to show you they knew how to make excellent sounding amps back in the day, and the Chinese DACs that are flooding the market can be pretty good. In fact the best sound I got from the Hegel was when I fed the SMSL DAC into its analog input.
Cheers.

Hello. I am a new diyAudio member and have just registered now. I own a pair of Beveridge 2SW-1 speakers which I bought back in '79 as store demos which was the only way I could afford them, barely, and that was a sacrifice to do so. I got a real good deal on them. Back then Harold Bev came to the store where I bought the spkrs, gave a talk and demo on his system and I met him then( and much later on called him to ask what a good dummy spkr load would be). I am still listening to these going on 45yrs. For the first 20 yrs I owned them they were 'on' almost as much as my refrigerator. I have a lot of info I can share with fellow 2SW-1 owners in future posts regarding failures, tubes to use, etc., but right now I am extremely eager to get my left channel amp back up and running. I have read the posts from cvanc, kcin, and others regarding these amps and it looks like I'm in good company.

I have attached the newer redrawn amp schematic for referencing for my question(s).
The failure mode (there were other failure types in the distant past which I permanently fixed) I have from time to time is that any of three resistors in the screen/cathode circuit of the 36KD6's partially burn up which blow the fuse. They are R201, 203 and 205 which are 10K, 22K and 10K, respectively, half watt, carbon film type. In this case, R201 failed. I replaced it and powered up the amp again and I could only hear very low level lower frequency sound from the spkrs. I hooked up the other good amp to these spkrs and played fine with no issue. I opened up the bad amp and traced a 1kHz signal through the driver board to find there was no signal at the collector of Q110. There was signal at collector of Q111. So the stators (electrodes as Rick Bev calls them) were getting no audio signal and the diaphrams were. So I replaced Q110 with a suitable equivalent (BD140) which did not fix the problem. If I remember correctly, there was signal at Q106/107 collectors. So after doing some more probing with my scope the amp started to blow fuses when I would turn it on and V204 tube arc'd bigtime in the base area of the tube. Q111 collector (which has signal) is tied to grid of V204 through the 1K (910ohm in my amps) resistor. The dilemma I am having in trying to continue probing is that in order to see the signal at the Q110/111 xistors, the HV has to be connected so there is feedback present through R1 and R3 at the bases of Q108/109. I confirmed this by disconnecting the HV on the good amp and seeing there was no signal at the collectors of these xistors when HV is disabled Back in the mid 90's I bought and built the softstart circuit boards which Ron Welborne (Welborne Labs) sold and installed them right over the main pwr xformers using 3 nylon stand-offs. They still work and are preserving the main xformers. Something I will try tomorow is to bring the mains voltage up very slowly with my variac and see if V204 will live and not blow a fuse so I can continue to check for signal at Q110/111 collectors. Measuring input and output voltages on the driver bd, up to the Q110/111 collectors, I calculated 28dB voltage gain.

If anyone has any suggestions/ideas to try please pass them on. Thanks much!

C107 and C108 (6800pF) on the driver board set a little bit of "voicing" - a dip centered on 2KHz. You can undo this by simply lifting one leg of both caps.

I've lived with this change for a while, here are my impressions. First it's big, you can certainly hear the difference. Second... it's left me wondering if splitting the difference might sound about ideal? It's a tad bright, but I've always thought stock Bevs were voiced ever so slightly dark, if that makes any sense.

There is a second EQ point at 80Hz, this is set by C103 & C104 (.033uF). This one can't be removed, it's way too big. C103 and 104 are the only reason these giant cabinets have any bass at all...

Hope this is helpful.

Good Evening Everyone. Am looking at 2 Mark Audio drivers. The Alpair 11MS and the Alpair 10 series 3 drivers. So the 11’s are a new driver with Mono suspension and a more curved cone. I just wanted to know which one will sound better? I can go with any one of these drivers. I know a professional audiophile who builds everything from scratch of mine swears by the Aplair 10 series # 3 drivers are the best speakers he has heard in the pencils. He has not heard the 11MS drivers yet. I have enjoyed the CHN 50 driver for a few years now and am looking to step up to a bigger and better driver and sound. Thanks for your help. Jeff

Hi all.

I own a Rotel RA-04 integrated amp which I bought new back in 2007. All was fine until recently and I’m having issues with the channels.

I’m only getting sound from the left speaker when hooked up to my CD deck, but weirdly I get stereo sound from an AUX to RCA through the amp.

I’ve tried all RCA inputs and the CD deck works fine as I’ve tried it on a spare amp I have.

I’ve also tried hooking up the speakers to Speakers B just in case it was those, but no dice.

Any ideas? It’s a great condition amp and I’d really like to get it working again.

Hi All,
Mixer amp came to me with a few problems. One problem I sorted by replacing C60 on the main power amplifier board.
Another problem that I need help with is that one of the output sides does dead when the unit is on for a short while. When working if I disconnect the speaker and reconnect the sound will not come back. I carried out this action on the other side and it does not lose audio o/p when reconnected.
Any help or suggestions appreciated.

It has balanced outputs and a 3.5mm single ended output socket on the back. i was using the single ended as my amp doesn't have balanced inputs, and I had a headphone plugged in the headphone output on the front. That cable got tangled round my leg while I was asleep and I pulled it off its shelf and the single ended output socket broke off internally. I have included some pictures. It looks like I will need to desolder the balanced output sockets first to gain access to solder the single ended socket back on.

Can anyone offer any help as I haven't soldered much at all and have never desoldered anything. I have a cordless soldering iron I got from Lidl that takes E10 tips (the screw on kind).

Also does anyone know how the ribbon cable disconnects? It links the output board with the main DAC board and it the only thing stopping the rear panel from disconnecting completely with the main unit.

Hey there I built my towers without consideration for the crossover and I just need advice before I spend any more money on it!
I have 4- 6 inch aluminum magnesium hi-fi speakers in each box and I need some kind of a crossover to get the sound as good as I can get with a 50 wpc tube amp? Any recommendations??
“They sounded great on the workbench in a series parallel before I even built the box “

Hi everyone .
There are large 15" and 18" speakers on the market. among these it is possible to choose the moving coil which can be 4-8-16-32 ohm.
According to your experience, can you tell me what are the differences between a 4-8 ohm speaker compared to those with a 16-32 ohm moving coil? . Is it true that the 16-32 ones are characterized by a smaller distortion? I imagine you need a suitable amplifier for driving.

EJ Jordan JXR6HD and Alcone. Designing a friend's speaker. Need get sealed cabinets good for 40Hz -3dB in room and let you know in due time.

http://www.ejjordan.co.uk/jxseries/jxr6.html

Currently, one of my Exposure IV Duals is out of action, and awaiting components.
Thought that, given the age of the amps, I'd take the opprtunity to change out the original 10,000uf screw types on both of 'em.
Would something like this suffice ; https://uk.rs-online.com/web/p/aluminium-capacitors/0189787
I'm drawn to the 10,000 hour lifetime spec....what else should be considered please??

So I am continuing to mull options for my future listening/HT room.

How would I go about modelling something like a line array of four 2"ish full-range drivers (e.g. MA CHN40) mated to an 8" woofer, crossed over at say 300Hz.

I'm wondering if this kind of design, across 8 surround/overheads might
a) give me enough low frequency SPL to avoid subwoofers altogether, and
b) allow me to eliminate (or massively suppress) "sweet spots" by EQing between them and whatever the main LCR are

Hello.
I have 50 kemet peg226mg337rqe4 capacitors 63v 370uf.
They are very good caps 150 degrees, used in automotive and planes.
Is 80 euro digestible?
I attach a measurement and data

I have gone through the threads here and read open source monkey box build and also the LCCAM 10.3 build. From what I read, this combination seems to be the best:

• Bliesma T25B-6 tweeter
• Bliesma M74B-6 midrange / VOLT VM 753
• Purifi PTT8.0X04-NAB-02 8" woofer
• Hypex FA503 amp

But I'm at my parent's place now and need a much cheaper 3 way studio monitor as a second pair so that I can use them here. What combination would you suggest?

Also open to passive builds or hybrid amp / dsp builds like LCCAM. My aim is to go cheaper even than LCCAM. Don't want to buy Adam a7x, Neumann Kh 120 etc. Neumann have too much midrange and I always end up under-compensating for mids in the mixes.

I'm also open to coaxial designs. (Use equator D5, Presonus Sceptre S8 and Genelec 8361 in my main studio - so my ears find it easy to mix in coaxials). I'd also be happy to buy some of these drivers off you guys if they are available.

I have a pair of 7199 tubes for sale, any interest?
i have added a utracer quick test for the triodes and will do the same for pentode section.
triodes look good

Here is a mixed lot of 8 indicator tubes and magic eyes, brands are telefunken and Phillips.
Em84/87 um4.
The lot for 40 euro.

Here is a nice nos pair 6146b transmitter tube, also used in audio.
The pair is closely matched 90 ma.
Asking 90 euro.

Buy Hitachi 2SK134

I have both of the above cable test boxes for comparison.

The voltage that I measure on the test tones outputs is different for both units.

How should I be measuring the output with a multimeter (AC/DC) and between which pins on the output XLR connector?

The levels to measure are:

+4dBu
-10dBV
-50dBV (Mic)

Here's a complete "turnkey" ORION+ 3.1 speaker system, factory built by Wood Artistry & designed by Siegfried Linkwitz. This includes the speakers, active 3-way crossover, ATI 6012 amplifier and all cabling required. You only need to provide source w/ volume control.

The ORION+ 3.1 are open-baffle dipole design, using an active 3-way crossover and 8-channels of amplification. The drivers are some of the best you can find (Seas, Peerless) and the crossover employs precision tolerance components throughout.

This pair is circa 2010, Rev. 3.1, turnkey systems started at $8400. The brochure can be seen here: https://www.woodartistry.com/pdfs/Orion-Brochure-102208.pdf

All grill covers included. Excellent physical condition, and all electronics work as they should.

Asking $2000 - Local pick-up in Las Vegas, NV or delivery available up to 200 miles from 89147

3 6005 tubes new, jus pulled one out for photo.
Theire yours for 30 euro.

1 piece nos telefunken ED8000. Triode longlife, just opened the sealed box to check condition .
Asking 45 euro.

And 5 5965 tubes .
3 sylvania
1 rca
1 jan rca
Untested but can test for a small extra price.
Compatible with e180cc and the 7062
60 euro asking price.

Here are 12 5963 tubes The 5963 is a Mil-Spec 12AU7. Is also interchangeable with European ecc82
They are untested but can test them for a small extra fee.
Take all for 85 euro.

Hello all,

I thought I was done with my three-way speaker crossover, but I was thrown for a loop. I am doing a Paradigm Studio 100v3 upgrade. I re-did the crossover and upgraded the woofers from the stock models to two Scanspeak Illuminator 18WU/8741T, where the factory frequency response (Fig 1) shows a reasonably flat response down to 75, maybe 50Hz. The woofers are wired in parallel.

After designing and testing my crossover, I ended up with the frequency response I was happy with (Fig 2). That bump between 50 and 110Hz, followed by the dip between 130 and 300 was always there, and I assumed it was some combination of cabinet resonance/room effects. After soldering the speaker together with 18 gauge solid core wire and installing the thick felt insulation that came with the speaker originally, I could tell that the bass was lacking. Testing (Fig 3), confirmed that the bass was not there, and when all three components were tested together (Fig4), I confirmed that the mid was doing the work down to about 200Hz (Fig 5).

I have tried about everything to troubleshoot this without taking the whole thing apart again, with consistent results. My only guess at this point is that the woofers aren't fully grounded. I soldered a 14 gauge solid core strand from the common ground point on the crossover to four 18 gauge strand that went to each speaker, and one 14 gauge strand that would go to the binding posts. Is there some way I can confirm/eliminate this suspicion with a multimeter?

This cabinet is well-braced, so taking out the crossover takes some contortion.

Any wiring suggestions or troubleshooting methods would be appreciated. Thanks

Two stereo 2x200W 4Ohm amplifiers (total 4 boards) with heatsink plates
$160 for 4 channels, two plates
PM me for details

Hello.
Here are 10 pieces nos 5902 mini pentodes for audio.
There is 3 sylvania. 5 Raytheon. 1 rca and 1 sonotone.
Asking 60 euro.

I've been using Mogami ultra-flexible miniature cable to wire my tonearm: https://mogamicable.com/category/bulk/ultra_flex_mini/

Specifically, the 2490-08, which is a two-conductor #32, with shield. I use the shield as the ground for both channels.

Obviously, leaving the shield and jacket on the loop from the pivot to the plug imparts some resistance/torque to the arm moving. It is fairly linear for such a small arc, though, and my wire hops off the wand at nearly the top dead center of my pivot, which minimizes the influence. I've measured the force imparted by the wire and simply compensate by using it as part of my anti-skating force,

I've tried other cabling arrangements where the loop from the pivot to the plug isn't shielded but rather twisted (substituting a third, insulated, conductor for the shield). I prefer the level of noise rejection I get with the all-shielded wiring.

Some of the higher-end unipivot arms out there seem to use some sort of a sleeve on the tonearm wires where they exit the wand and travel to the plug/jack, and I wonder if there is a super-flexible sleeve that provides some EMI/RFI rejection? I've looked at braided copper sleeve and it seems pretty stiff.

Basically, I'm looking for suggestions for improving this aspect of my arm. I've seen alternative shielded wiring from outfits like Daburn, this wire is even smaller than the Mogami. The Daburm is less than 1mm for the two-conductor #40, versus 1.7mm for the Mogami. I'd love to try some but the minimum order seems to be a rather expensive spool of the stuff (hundreds of US dollars). if anyone knows how to get Daburn cables by the foot, I've love to hear about it.

As it is now, I have no problems with extreme tracking. I have cartridges rated for 100um @ 1g and I can certainly hit that no problem. I just feel there is room for improvement here.

I've included a picture so you can see how my arm is wired, and the loop I'm trying to optimize.

Hi, I am looking for replacements for 2SJ99/100-2SK343/344 Transistors
I've been searching for info on the internet but finding conflicting information.
I found someone recommending 2SK1058/J62s would be electrical equivalents, although the mounting would have to be modified, but elsewhere seen them listed as being Vertical Fets, so the 58/62s would not be suitable.
Checking the reprints of Hitachi datasheets, they don't appear to mention what type of fets they are.
Can anyone please help me out?

If there is an experienced DIY'er from Denmark that wants to build the J2 clone as mono blocks I have 2 x chassis + skinny boards. I have too many projects and those chassis takes up space. It needs to be a person from Denmark as pickup is the only possibility (Copenhagen). I also have -+24 VDC SMPS as it was the plan to built with those and have space enough inside chassis for extra filtering of the SMPS (Meanwell's). If interested we can find a good price for chassis, boards etc.
Chassis still wrapped in plastic. They were shipped assembled. High quality chassis.

Hi,
I'm currently planning to build a Tubelab Simple SE amplifier, and I'm at the stage of choosing output transformers.
My initial plan was to use the Hammond 1628SEA, but after some research, I'm considering other options that might offer better sound quality.
I've been eyeing the Hashimoto HC-507U and Iso FC-20s. Both transformers are smaller and lighter than the Hammond, they deliver 20 Watts vs 30W for the Hammond.
I'm concerned that they might not be powerful enough for my speakers, which are Monitor Audio GS20s rated at 89db (6 ohms). My room is quite small (4x5 meters), so I guess don't need an overly powerful amp.
I'm hoping to get some insights from experienced tube amp builders on this matter.
Would you recommend the Hashimoto HC-507U or Iso(tango) FC-20s for a Tubelab Simple SE, or would the Hammond 1628SEA be a better choice ?
Any advice or recommendations would be greatly appreciated. Thank you in advance!

Two years ago, I have tried to use TOSHIBA TC9459 volume control IC, but failed.
Yesterday, after successfully codeing Muses72323, I tried rewriteing the code for TC9459, it successfully made the IC working.
This is the testing schematic


the datasheet of TC9459
https://github.com/jerrylong-km/TOS...71ea65316247f8d16d08897f/东芝TC9459F-音量控制芯片.pdf

Hello everyone,

This is my first post here so i appologize in advance if this not the right place to post !
So for a sound installation i have to come up with an "autonomous" sound player. The idea is that when people will come in front of the installation, the music will need to start, either by pushing a button or by detecting their presence, and then stop when no one is around/loop if people are still around at the end of track. Here are some more infos :

- The hardware will be hidden inside the installation.
- It will be a "permanent' instal so it needs to be reliable in the long run.
- It should play .wav from an SD card.
- It should have two powered speakers.
- It should be started easily, by anyone, by just pressing an ON switch and the whole system must be ready.

Is there a solution on the market that i'm not aware off that would fit my needs ? Or do i need to do it myself with circuit boards such as those ones : https://www.amazon.fr/Récepteur-damplificateur-puissance-numérique-Bluetooth/dp/B075N8F4YD

I'd take any kind of help, thanks for your time !

I'd like to have a non-magnetic parts list here on the forum, as this seems to be a 'item of concern' for the more aware of us, when it comes to sonic quality-at it's finest. I ended up thinking about making such a thread that was and is -specific-, due to having little in the way of a specific thread on the forum! After an hour of searching, I decided that frustration would be the norm, and to attempt to remove that aspect for the next guy who does the same search. I mention dates on some parts,as things might change on the more expensive stuff which is low volume and is built specifically for it's sonic qualities. For example, on the later mentioned Teflon tube sockets that are $25 each - they might get wise and make a change. You see, the parts are supposed to be OFC and 24k gold plated--and that's it. But testing is showing that a bit of magnetic material is in there.....

Whatever the item series of devices, if you know it is non-magnetic, be it resistor, capacitor, transistor (yes-possible!) or whatever (sockets, switches, and potentiometers), please add to the list.

Please report in the given item it if IS magnetic as well, to help remove doubt, or doubt would abound-if the given specific item was not mentioned here. Also, some parts like resistors can be 'slightly less' magnetic than others, so might serve well, when it comes to being a second choice.

I was specifically searching for non-magnetic electrolytic capacitors.

So far, I've come across..in my pile'o'stuff......:



Rubycon 'Black Gate' electrolytics: Non-Magnetic

Elna Cera-Fine Electrolytics: Non-Magnetic

Elna SilMic Electrolytics: Non-Magnetic

Sanyo Os-Con Capacitors: Non-Magnetic (purple skinned)

Sprague 'Os-Con' capacitors: MAGNETIC! (Older series-blue skinned)

Most (near 100%-I mean, tell me if there is one series that isn't!) of all Panasonic Electrolytics: MAGNETIC

Most all series of Nichicon Electrolytics: MAGNETIC

Most all series of United Chemicon Electrolytics: MAGNETIC

'LittleFuse' ceramic bodied pigtail fuses: Non-magnetic

'Connex' teflon sockets at 'the parts connexion': the mini-9 pin sockets components (the metal bits) are VERY mildly magnetic. (tested 7/20/2008, a 7/26/2006 purchase)

Vampire Wire OFC Female inside mount RCA jacks: Mildly magnetic

Xhadow OFC speaker spades: Mildly Magnetic

Здравейте. Много харесвам CD плейърите на Philips от ранните им години. Наскоро взех cd 200, philips/sony. За съжаление с дефектен демодулатор saa 7011, открит чрез замяна с работещ, взет от CD303. Имам няколко работни saa7010 бр. Не мога да намеря saa7011. Въпросът ми е има ли успешна смяна и на двете ИС? Тук има тема от 2009 г., но съветите, дадени там, не работят, опитах. Съжалявам за гугъл преводача. Поздравления

Hi,
I am debating on building budget centre, surrounds and atmos speakers using arrays of 4 Peerless TC9FD. I would be using small closed boxes for them with DSP.
From what I see, 4 of them in series+parallel should give me the same impendance as 1 speaker and should then comfortably go to 120Hz(where they would be crossed) - I only play up to 90dB max.

Am I missing something or is this a good idea?
Alternatively, I could use SB12PFC25-4-COAX, but including crossover only 1 of them would far exceed the cost of 4x TC9FD(I only have 1 channel of dsp per speaker avalable for each).
Thanks for your help in advance.

Fronts are Bliesma t34a+aluminium 6.5 Purifi.
Bass is 4 separate Scans 32Ws

Hi to all the tube lovers! I need the schematics of that beautiful preamp to make some mods, in particular coupling caps and cathode resistors.
If someone have it pls send me a copy, thanks!!!

Ciao, Roberto

Complete STK3152-III counterfeit PCB required for SANSUI A1200 DC Servo Amplifier

SOLD..SOLD
Westmore 501 / Triplett 3444 Laboratory Vacuum Tube Tester
I have this listed on Audio Mart,.
Will discount for DiyAudio member; PM me.

https://www.usaudiomart.com/details...1-triplett-3444-laboratory-vacuum-tube-tester

Hi,

The RSS390HE-22 seems to be one of the new Dayton Audio subs on the market. I was all set to order the UM-15 but started looking at the options and came across this newer option. Has anyone tried one? My main use case is 75% audio and 25% home theatre, I'd give up the lower few Hz for a more refined sound. I was looking to go with a 2.5 - 3 cu.ft sealed box vs vented and use my miniDSP HD to boost the lower end and with some in-room gain it should dig deeper enough.

Thoughts or comments?

Hi, I am retired and try to mess about with electronics & stuff to keep a few grey cells active.
My first "Hi-Fi" was a Garrard Deck + TripleTone valve amp feeding an 8" dual cone speaker in a triangular baffle hung from the picture rail in the corner of my bedroom. When stereo came in I doubled up on the amp (control spindles projected from the back so you could join them) and moved on to a Goldring Lenco 75 (in preference to the then standard Garrard 301) with KEF speakers in home made enclosures.
I still have a couple of old KEFs here in Goa but to meet down-sizing space constraints in the UK I was lucky enough to find a cheapish pair of mis-treated Spendor S5e's to restore. I can't decide which I prefer.
I am currently in the process of building a spare pair of speakers using 'moderately priced' components (see my post on the Beginners Crossover forum.

Cheers (_)?

I just tried a very simple Amp with the 6E5P tube.

I have very efficient speakers, so I can life with around 1,2 Watts.

But the sound of this amp is so good, you would not believe.

Every detail is very clean and precious.

Even the bass have a good punch.

The schematics I will post later.

Hey guys,

So I've made a few HIFI units for myself without a lot of issues and they sound great. My company does activity funds so my plan is to have them come to the shop (I run the manufacturing side of this electrical engineering consulting company) and build a little two way system.

The plan is to make 30 of these units. One unit for one employee and they can bring whoever they want to help them assemble it. Seems fun

I am limited to about $60 a person so I have this dayton 4" high excursion woofer and this mini tweeter plus a tiny amp pushing 20w. I'm trying to cross them around 4k hz. I've never done this with a budget so low and I'm having issues with the impendence graph as you can see below. Usually I have higher end components I can choose more carefully so the Xover doesn't need to be so severe. Its all over the place and I'm wondering how to fix this. I want to use this woofer specfically because I am able to get this thing down to 40 hz Fs using some unique methods I've learned building subwoofers. The tweeter I am not married too. I can swap that out with anything you suggest.

Does anyone have any suggestions of what I can do to get this to behave?

Mini Planar Tweeter 6 ohm:
https://www.parts-express.com/Dayton-Audio-PTMini-6-Planar-Tweeter-6-Ohm-275-083?quantity=1

4" Woofer 8 ohm:
https://www.parts-express.com/Dayto...-Cone-Midbass-Woofer-8-Ohm-295-416?quantity=1

I appreciate any help anyone can give me here. Would be a shame to make 30 of these and have them suck

I got some t545 from my boss and it looks like it needs reconing. Anyone know where I can find a kit?

Hi,
Does anyone know of equivilent part numbers for the following:

* Hitachi 2SD669
* Hitachi 2SB649

BTW, the package is a TO-192...

Here is a link to the datasheets.

The circuit designer, Randy Slone, told me that some people replaced them with components from the MJE series but he couldn't remember the part numbers. I believe they are made by motorola but I cannot find any datasheets.

Any help would be GREATLY appreciated!
Thanks in advance!!!
Gaz

Hello guys
Im new to this site, its my first post here.

Just recently I got set of nice 604 e with original crossover n1500. Had to scrap the boxes as those were really tired. Plan is to have new crossovers made for them. Copy of the originals but with better components and new cabs. Either stonehange V if i get the plans or Billforts corner boxes.
Any advice highly appreciated.

Thanks

A set of great quality 3 x IEC and 4 x EU style 2 pin connectors plus snap on Ferrite cores. Also included are a bunch of IEC panel sockets and 1.5M of high quality 3 core 14AWG cable.

Only selling as I am using Neutrik Power-con connectors.

SOLD

hey, i got these speakers from my dad and they are around 10-15 years old, one speaker is working correctly but second one everytime when i turn it on i need to raise the volume in order to i assume turn on the relay between amp and woofers + tweeters to make it play music, so lets say that i listen usually at 40% volume but i need to raise the volume to 80% to turn them on and now i can go back to 40%, few weeks later i noticed that this column also has less bass and more treble, when i play 80-1000hz frequency at higher volumes sound is disorted/crackling? this does not occur in the fully working column and i think this could be caused by old caps inside the speaker?

there is available online service manual with circuit diagram and parts list for them and yamaha used electrolytic caps for 15v regulator, mix of ceramic and electrolytic caps on the preamp and mix of electrolytic and film caps on the amp and aside of replacing these old electrolytic caps do i need to replace film and ceramic caps as well? if its possible would there be any benefit in using polymer/aluminium polymer caps?

i live in EU and these speakers were imported from US and i need to use step down converter with chinese sounding name that does not sound trustworthy and i was wondering about converting them to 240v, according to yamaha service manual 120v and 240v versions have different fuse, power cord and the transformer, transformer doesnt have taps that i could rewire and i couldnt find any info about it online, at the output of the transfomer there is 600v full bridge rectifier, i saw one disassembly video of EU version and transformer looked identical to one in US version so im wondering if its possible that this transformer supports 240v? is there any way to check that? if no i would just have to buy transformer that has 240v input and outputs the same voltage as the current one right?

I'm replacing the diaphragms in a batch of HF108s and discovered they have varying qty and thickness shims under the diaphragms. I tried contacting Faital for the correct procedure in determining the required amount and thickness of shims. I'm pretty sure they're just tweaking the VC offset for lowest THD, but its not clear how they measure it or what their standards are. Has anyone else dealt with this and received any guidance as to the official way of dealing with this?

Looks like Fiio created a new portable cassette player (Walkman). At first glance it looked like it was a decent piece. If you look a bit closer, it's actually a cheap plastic device. Compared to a basic vintage Sony or Aiwa player that can still be bought on the used market, they are charging around $120 for this plastic wonder. So they essentially succeeded in making something mediocre even worse than it was and for more money too.

Just like MP3s did for 44.1k sampled digital audio, they made cassettes sound worse than they already did. I'd however venture to say that a decent diy recording on a high bias tape made with a higher end deck still sounds better than any MP3 does (discounting the little bit of tape hiss). I'd accept the hiss any day over the compressed audio.

I have found an EKOsynth 15 that's available for a pretty nice price, with one catch - the main DCO board is missing.

It was probably cannabilised by someone who had a nicer looking unit whose own board died (this particular example has a few blemishes and some slider knobs missing. I can live with that).

It's a cosmically stupid idea to rebuild the main board, right? I would have help from professors in my college - they'd probably laugh and shake their heads at me in a sort of, "what has he done now," sort of way, but they would help nonetheless xD.

The schematic and layout can be found here on synthxl. The main thing I'm concerned about are the mystery ICs that don't give me anything back when I search them online. They probably have something to do with the 'Digital' part in DCO. If they're irreplaceable and/or preprogrammed in some way, I'm snookered. If not, the rest is just mainly just some transistors and OTAs - moog stuff through and through, basically. Nothing that hasn't been D.I.Y.'d before.

So - what do y'all think? 😆😀

Thanks in advance for any help!

Sorry this is not DIY but I'm not sure what to do with these, they are such good quality and wasted stored away. These belonged to my Mother who has severe Alzheimer's now, such a devastating disease, I would like the recipient to donate funds to Alzheimer' Society UK.

Preferably all taken as one lot but can be split up if wished. 17 LPs in all. Really I only need the postage fees sent to me, and please make your considered donation to the cause. Whatever you think is fair. £2 - £3 each maybe?

All LPs are practically mint, hardly used, some beautiful recordings here. A treasure for a classical fan with a nice turntable system.

Weight for all 17 is around 5kg - tracked 48 is only around £7 UK post, EU around £20.

Further pics and a detailed list will be posted here later if required, just getting the offer out of the way for now.

Thanks for looking and anything you can offer.

ALL TAKEN, MANY THANKS

Does anybody do this - fit 2 different type sockets in your amp to try alternative tubes?

I first did it with rectifiers, an octal and a UX4 socket next to each other so I could use 5U4 or 5Z3. And just now I fitted a pair of Y8A sockets and a pair of side contact sockets to one amp so I can use EL12n or EL6. But as I was doing so I realised that these old sockets, which were used in enclosed radios, have very exposed connections with voltage on them. Particularly side contact sockets. So I'll have to make a cover for the sockets not in use. This is not difficult to do.

Most people use Chinese socket adapters so the problem doesn't exist, but I'm wondering what you guys do if you fit alternative socket types?

I need some advice.

I will be attending a DIY speaker conference where I will be giving a demo of some speakers I have built. I don't have a lot of time for the demo. I would like to assemble a single audio file which contains short excerpts of various musical files. My files are mostly 24 bit/96k flac files.

What is a good tool to edit and splice my music files? I would like to maintain the 24 bit/96k resolution of the originals. Please assume I am a newbe. I have occasionally used the native Windows function to rip a CD into *.wav files, but that is the extent of my experience.

Thanks ............ j.

Please find some pics of my new amplifier, this works a dream with no issues at all. To my ears sounds very good. What do you think, the tiger eyes light up blue and indicate the PSU is healthy. There are quite a few threads on this site indicating issues with this design, well this one works 100%
regards Nick

Hello,

A friend dropped off an amp head for me. This is the model with an ECC83 in phase shifter. The amp dates from 1973-74.
The fuse blows. The power supply capacitors are original. An EL34 is rinsed. The transformers are not cut, The zeners are heated well.

After research, in addition to changing the 100uF 450V and 20uF 450v capacitors, I was thinking of changing the diodes and resistors of the power supply (low voltage and high).

zener by 5W, diodes on the el34 anodes by THT (4000v) + capacitors (MLCC, Through-hole, 1.5nF, 2kV dc, ±10%, dielectric: X7R)

I am giving you 2 diagrams because the one that interests us is illegible while the other is close (2475-130) and... more readable!

If you know these amps and/or if I make a mistake (with the 5W zener instead of 1W for example), please tell me.

After 18 years challenging myself, learning from you and sharing nice projects I will leave this forum.
Also because being bullied and get physical threads without support of the moderators for the last 18 years.
See you all on the next forum.

R.I.P by mod.

Hi all,
I bought the AN/E kit speakers probably 20-25 years ago, really enjoyed them but when I started playing about with vintage full range drivers and DIY I pulled the drivers and crossovers and junked the cabinets I'd made to save space.
A friend of mine wants to build a valve amp, so I'm helping and suggested he try my audio notes.
I plan on building them into AN/J so if he doesn't go for them they will be small enough for me to use as a second system.
I've replaced the foam surrounds that had both disintegrated.

Only problem is I've lost the build plans. I know the outside dimensions and can experiment re port length but wondered if anyone can help on details,
is the baffle double layer?
What thickness is the ply?
I remember a brace under the midbass, what dimensions is it?
Any help much appreciated.

For context the amplifier is being bread boarded to work with a variety of tubes I have in stock so my friend can see what he prefers. 6cb5a, 300b sv811-10a and a variety of other sweep tubes, setup can use D3a, ef180 ef184 6j9 etc as drivers via power drive, Should be fun to rattling through the permutations!

Many thanks
Enzo

Hello people,
Recently I installed a piezo tune-o matic bridge to my guitar. Also I made a piezo preamp in given link, in order to match impedance stuff. https://till.com/articles/GuitarPreamp/
My problem right now, there is too much volume difference between piezo pickup and my humbuckers. I am not an expert on circuits, I just know tiny stuff about them. Is there any way to modify the circuit in order to reduce the gain or do you guys have another preamp suggestions?
Thanks in advance!

ARII 3.19 rel-2, mint kit, all bags unused, never had time to build it,
paid EUR 127,-- to Jan Didden incl. shipping from Belgium to Austria,
this is my price, too.
Payment in advance via banktransfer only ( BIC, IBAN ), no paypal.
Shipping to EU countries only.
Details via pm, thanks.

Hello;

Switching noise coming from SMPS are over the audio band.
I saw some designs using LC filters to get rid of this unaudible noise.

I do not know the THD+N measurement details but the noise (+N) should be the noise in audio band right?

So could you please explain the reason of why these noise degrade performance of DAC chip or opamps?

Ok, it’s an oxymoron. But, as I kind of expected, my daughter’s budget for an Oris horns system evaporated in the realities of rehabbing a house built in 1900. So, I looked in my cabinet of unloved hifi parts to see what we might be able to do. What I’m thinking:

Tapped horn, Volvotreter’s DIY 30hz Tangband, 30-80hz (pair)

Mid bass, EVM-15B on DIY straight exponential horn, 80-400

Midrange, JBL 2105 on DIY Edgar tractrix horn, 400-3500 or 4000

Tweeter, Jensen RP-103 horn 4000-12000

Super tweeter, Radio Sack 40-1310, 12000 up

I have all of the drivers except for the Tangbands, but they’re fairly inexpensive. Amp is a Pilot SA-232 she has (may convert to triode). No DSP to start, traditional crossovers midbass up. TH’s crossed with midbass electronically and powered by plate amp (TBD). Biggest outlay will be for wood; a lot of fabrication but my son-in-law and his brother are wanting the challenge.

Yes, without DSP level matching will be an issue, and it’s a guess on how flares and dispersions will integrate in the room. DSP may be in the future.

I’m trying to not stretch the limits of any given horn. Thoughts and rationalizations:

TH – proven design, plans available, though the current W6-1139SIF sims differently in hornresp than the W6-1139SC Volvotreter uses. Adding an inductor, as he does on his 38hz version, smooths the response considerably. Probably as low as I can go with a TH and cross at 80hz without issues.

Midbass – inspired by Volvotreter 77hz horn, modeled in hornresp, changed to an exponential flare and increased the mouth to be 1/2 size. Plan to use multiple layers of bending plywood to fashion the exponential side profiles. May be a challenge to build, but that’s why I have a son-in-law.

Midrange – from Dr Edgar’s Speaker Builder article. May cross at 3500 instead of Bruce’s 4000 to reduce beaming potential and the 2105 running out of gas. Thoughts?

Tweeter – the Jensens are sweet sounding, and I have them, came out of a Pilot console with above amp. Crossing higher on the bottom and lower on the top than typical should keep them out of any mischief, and easy to cross gently. A 16 ohm driver in the midst of 8’s, tho. Potential future upgrade.

Super tweeter – decent performers, and I have them. Fill in before the Jensen phenolics run out of gas.

As an alternative, I could build the tractrix mid for a discontinued Polydax dome driver up to 5k and cross it to a JBL 076 I have, to make it a 4-way, but I am afraid of the tractrix beaming and reliability; correct 076 diaphragms are long unavailable and Bruce switched from domes, as he found they tend to burn out. My daughter and her husband should be able to recone or replace any of my choices (except The Tangbands) for a number of years.

Any comments or criticisms welcomed!

Anyone else love listening to these rather broad offerings? Or different presentations of already known artists.

Anyways, they're great. Tons of great content to dig through. 🙂

https://www.youtube.com/channel/UC4eYXhJI4-7wSWc8UNRwD4A

I built this pair of speakers for my brother’s workshop/garage. He has speakers on his workbench on either side of a PC monitor, and he is often standing at the bench as well as sitting. He needs the speakers to sound good in the nearfield, as well as being able to fill the garage with music.

His current speakers are the MTM version of the Paul Carmody Overnight Sensation. He likes these speakers, but when standing at the bench, he feels the tweeter is too low (it is basically aimed at his belly). I also believe that the MTM configuration might be aiming a null at his face when standing close.

I thought that making a new pair for him might be a fun project. He had some specific requirements:

• Maximum width of the cabinet is 7”.
• Tweeter must be at least 17” above the bench.
• No paper drivers due the garage environment which has drastic changes in temperature and humidity

I have worked with the SB26CDC tweeter several times, and it is a great choice in the sub-$100 market. The sensitivity of 89 dB/m/2.83V is a bit low, but a small 2-way speaker is going to be low sensitivity anyway.

I wanted to use the SB17CAC35 woofer, but they were sold out in North America when I placed the order, so I used the very similar SB17NBAC35. I chose the 8 ohm version for two reasons. First, the Qts of the 8 ohm is more suitable to a sealed box, and second, his garage amp is an older A/V receiver, and he sometimes drives 2 pairs of speakers with it… no sense in burdening the amp with another 4 ohm speaker.

The cabinet was built from inexpensive “birch plywood” from Home Depot, labeled as made in Indonesia. I did not want to eat into my limited supply of Baltic birch, and I thought I would give this product a try. The plywood had some voids which had to be filled on the edges. It did not cut, machine, or sand as nicely as the Canadian made cabinet grade plywood I get from my hardwood lumber shop. There is no issue with the finished cabinet in terms of performance, but there was more work than necessary in working the material. In hindsight, I would have made the 30 mile trip to the lumber shop and paid $20 more for a sheet of maple or birch faced cabinet grade plywood. From now on I will stick with the Canadian stuff when I can’t get Baltic birch.

As I mentioned earlier, this is a sealed box design. That is my preference, I just prefer the quality of the bass from sealed box designs. It also reflects my own limitations as a designer. I have never been really satisfied with any vented box speaker I have ever built, and I find it very difficult to get the damping level just right so that both the bass and midrange sound correct. I have great respect for designers who can find the right combination of vent location, damping, tuning frequency, etc and arrive at a great 2-way vented box speaker. I am not one of them…



The baffle is double thick. There are three partial bulkhead braces.

The woofer is positioned at 9 13/16” from the bottom. The tweeter is positioned at 17 13/16” from the bottom. Both drivers are centered. The tweeter is recessed, but the woofer is not. The cabinet is only about ¼” wider than the woofer frame, and I did not think that a recess router cut would be successful with such a narrow edge distance.

The bevel cuts around the tweeter are at 33 degrees. The tapered bevels on the sides were made on the table saw with a wedge jig I screwed to the back of the cabinet. I selected the taper so that the bevel would begin at the point level with the top of the woofer frame. Around the tweeter, I wanted a ½” edge distance between the bevel and the tweeter recess. So, those two points set the taper angle. When I was cutting the bevel along the top, I screwed up and made the bevel deeper than I intended, so I have only about 1/8” edge distance between the top bevel and the tweeter recess, but fortunately there was no tear out or other problems. The tapered bevels below the woofer are for aesthetics only, they have no affect on the woofer directivity as far as I can tell.

The cabinets were stuffed with long fiber loose wool, well fluffed. I measured out 192 g of wool, which gives me a stuffing density of 16 g/liter, or 16 oz/ft^3.

We are taking our second ever cruise and we are taking a Pacific Island trip with Cunard. Although we have no intention of leaving the ship, if I want to visit Fiji or Vanuatu we'll do that at a later date and stay a month or so.
We've read the pre-boarding instructions and talked to some people who cruise a lot and being an old bushwalker and mountaineer I've bought my wife and I some brightly coloured waterproof jackets as part of a "ditch-Kit" for want of a better word as the advice from Cunard is that if there is an emergency we are supposed to head to our cabins, don warm clothing and sensible shoes; take our life jackets in hand and proceed to our designated main assembly area .
I'm getting a bit of stick on one forum for "wasting money" on something we'll never get to wear; especially if we have to abandon ship.
Anybody here do much luxury cruising and actually read the instructions as I have and take aboard such a jacket ? An unlikely event I know but there are these things called rogue shipping containers that cause trouble and they are everywhere. Besides which the coats will stay in the cars afterwards in case I need tio change a tyre in the rain or for putting on snow chains
An experienced traveler we came across said they used to be crew on liners before retiring and they now cruise a lot and they say they always take a ditch kit on board and they advised adding a small torch and whistle to the jackets pocket. Interested in the thoughts of the hive mind here. Total cost of the emergency package for both of us $55- local as whistles and small waterproof torches are something every bushwalker and skier tends to have and carry and the jackets were clearance items, bright Flouro yellow Hi-Vis but ultra light and compact.

Hi guys,

Have a DWM4070NV2 driver board from a Ground Zero GZPA 1.10000SPL to rebuild.
L2, L3, L4, L5 are all burned beyond recognition - what values are those inductors ?

I'm missing also Q2 + Q10 ? Are those the same as in DWM3640 marked as "MAX" transistors or not ?
I know driver board looks badly burnt, is there a place where a new driver board can be bought if i won't be able to repair this one ?

Looking to buy a Sigma 22 PSU from AMB, assembled or not.

Thanks
Do

Hello...new here...diy in many things but needs some input from tech in electronics 😉
As per the the title....stopped recognizing burned dvd-a.
Cleaned the lens...same issue persist...something on the mirror itself?..
thanks

Ignoring X-Max issues, what is the effect rear-mounting a driver opposite a smaller cut-out?
e.g. a 15" driver with 12" cut-out. I thought the idea ridiculous until I recalled I had sone PA horns built this way.

I bought a cheap Chinese SE amp many months ago to drive my tweeters - see this thread: https://www.diyaudio.com/community/threads/chinese-el34-6sn7gt-se-unusual-topology.401911

I disassembled it and fitted separate Glassware PS11 HV power supplies with separate chokes. Without the tube rectifier, the HT increased from about 320 to 368v - same for each channel.
With 330r cathode resistors (bypassed with 470uf) current is 73ma, anode voltage is 346 (22w), screen grid, connected to the UL tap is 355v. Grid resistor is 220k.

I then built an Akido Noval with 12AT7 input/gain stage and 12AU7 for low impedance output. Overall gain was about 12x..
https://www.diyaudio.com/community/threads/akido-preamp-query.408669/

There is no local or overall feedback so I don't think the results are too bad. There is no hum or noise short of putting an ear right against a tweeter.

I have an ANK 4.1 DAC, which I want to connect directly to a power amp.

The tube + OPT output stage of this DAC delivers 2 Vrms with 13 Ohm output impedance, which makes it ideal to drive a power amp without the need of a preamplifier.

And now it comes my idea to control the volume: instead of using an attenuator (either resistive or inductive) between the DAC and the power amp, I am thinking about using a variable IV resistor in the conversion stage.
In that way, the output signal amplitude would be linearly proportional to the IV resistor value, and there would be no need to attenuate the output signal.

I haven't thought about this in depth yet, and I haven't done any simulations, so I might be overlooking some details.
Has anyone in this forum done anything similar to this before?

Thank you in advance for reading this and for any suggestions/thoughts

Not that I need another turntable, but I really want to get this old Broadcast Electronics 12C deck back up and running.



The table is a commercial quality 3 speed idler drive. Broadcast Electronics was I believe the last company to manufacture the 12C table that began with Russco and later QRK. I've got new suspension grommets for the motor and I need to replace the felt on the platter, although I'll probably line the platter with chamois instead of felt.

I've got the awesome Karmadon cloned Gray 108 tonearm and I need to decide what cartridge to set it up with:



The arm is a faithful clone of a classic Gray Research 108 broadcast arm made of a magnesium alloy. These are a fine piece of kit.

Any recommendations for cartridges for such a set up? Under 1K USD budget, although I'd really be happy to keep it around 500.

Thanks,
eso

Kind of hard searching for results, so many questions on bias, like trying to find a needle in a haystack. Now this is not a Instrument question, just came across this when killing some time watching videos. In this video Uncle Doug adjusts the bias on the amp from 40% to 70% and in each increase in bias current there is an increase in gain and an increase in power out. Is this real or an error in measurement? We will skip ahead a little.

Login to view embedded media
And the final result.



Is this right and why would there be more power with more bias current? Inquiring minds want to know.

Hello guys, Im working on a small headamp project which will have mosfet (IRF520) classic source follower as the output stage. Currently Im using 200ohm resistor, class A, idle current about 150mA. Currently Im using 60ohm resistor. My question is this: I have lying around some chokes currently intended for tube amplifiers power supplies. Thy are rated at 5H 200ma dc current and they have DC resistance of 60 ohms. Can I use this choke instead of the resistor? The voltage will be the same. Will this ramp up the voltage headroom and efficiency and increase dynamics? Anybody used this with MOSFETs? Thanks. Im pinning my current schematic. (edit, in reality, 20k multi turn trimmer is used to set the bias instead of the 3k7-9k resistors)

Hello,

in photo the last LCR stage "full trafo", two stage/channel.
The coils for LCR, step up and interstage are made custom from Eltra Torino , in Italy.
The trafos for tube are from Sowter with Ni, ratio 4,5:1 , custom made
The power trafo from Fiat Transformer in Roma






The start point was this proto with full Tango trafos ans EQ2L




But they are scarce and expensive so I work on alternative also for tube.

A very interesting exercise.
And the name of it is LiberTango ( also a reference for Astor Piazzolla)

Walter