hi- anyone know a good place to buy vu bulbs- specs are 6VAC @ 14 ohms 20mmx3.75mm- thanks

Hi All,

Does anyone know what size screw thread is used on the securing bolt for the case.

I know it's not metric. is it BA BSF or something else?

Thanks
Andy

Greetings to all.

My name is Marian, i'm new here and I'm sorry to bother you with this but i'm kind of desperate, i have a problem with an EV 7300A power amplifier and i'm in great need of help.

The problem is with channel 1 with is silent, the protection LED on the front pannel stays on permanently, so the power amp inside is closed, this would seam to be cuse of some DC ofset voltage at the output that i have found but i cannot find the reason why it is, i have removed all the power transistors and checked them out and they all are ok, as are the other transistors on the board, then i have checked the other active components ( diodes, zenners ) and they are ok as well, i did found R31 to be foulty ( interupted ) and replaced it, and the power on LED on the board CR21 shorted out, i've replaced it either, now as i was nosing around i found what it first seam to be the the problem with OP Amp NE5532, i found a big difference of voltage between the rails at it's pins, as the negative one was ok at -15Vdc, the possitive one oscilating around +5Vdc, since all other components seam to be ok i have removed the OP and with it removed the voltage rails returned to good working size, +/-15Vdc, then i replaced the OP with a new one but the problem did not go away, i have put the old OP on the working module and it is ok there, but here every time i put the IC in the socket the possitive rail goes down allot, throug thoroughly verification i have found that the main positive rail goes down in fact ( that is measured against the ground ) so i have changed the power line with the one from the working module but still the same, with the NE5532 in it's socket the main positive voltage rail goes way down at a slow but steady rate, that i cannot understand why, i have also found an strange ( to me that is ) voltage difference between the power lines of the modules, i mean that as the working one has a +78/-53 Vdc the foulty one has +59/-72Vdc, i also verified most of the capacitors, searched for blown or defective resistors and came up empty..🙁

Now i came here to you askin for help of any kind, i realy need to solve this amp as it's one of my best friend's amp, so any help is greatly appreciated.

Here is the link to the manual http://archives.telex.com/archives/EV/Amplifiers/Owners%20Manual/7300A%20Owners%20Manual.pdf, and thank you all for your time.
Marian.

Hi,

My decade old Creative Inspire 5.1 5300 started to show problem recently; the popping comes out randomly.


I am thinking of replacing the amplifier board, is there any recommendation on the board?


Alternatively is to do build standalone amplify, using back the existing speaker. For the sub-woofer, I think I will just make it a passive speaker. Any pointers for the board, and the necessary casing?


I am ok with doing some soldering.


Regards.

Looking up something else I stumbled across something on the TI site suggesting with an active second order filter the second stage filter should have wildly different component values, say 10x the capacitance and 1/10 the resistance, or the other way round (it would help if I could remember which).

I've never heard this before or seen it on examples. Anyone know anything about it? As I said, I was looking for something else and at the time what I reda didn't sink in (I was looking for advice on feedback resistor values).

Hi unfortunately I have all my music as downloads to my PC from itunes at there best quality download. I realize this is subpar quality for many of you but I am wondering what is best way to play it through my home stereo for best audio quality?

There are so many options available. I usually just plug my USB stick in my Sony Blu ray player and it does a reasonable job but should I get some music dedicated device instead now I have upgraded my speakers? What about a DAC are they used for this purpose?

I know itunes have a big upgrade to lossless planned. But currently I only have the 256 format.
Regards Tim.

Selling my highly modded Naim CD5i.
Time to say good by to this nice player, as I it collect dust and someone may enjoy his gorgeous sound.

It has a huge number of modifications that I'll not list here. Worth mentioning Burson opamp, Schottky diodes, BHC capacitors, lot of oscons, silver-mica and regulators.


Will go for 700euro.
Shipping 22 euro to EU.
contact me @ tiberiu _ vicol at hotmail dot com

Regards,
Tibi

Hi all,
I recently posted for help designing a tube output stage that would exploit the unused power from my preamp PS. Several contributors helped identify the current limits of my supply, and shared advice on what output tubes might meet my design criteria. I have been reading up on amp basics, limited yet to SE triode mode configuration.

I took two recommended tubes and plotted some load lines. The 6l6 will be underutilized in my build, and the ECC99 maxed out. I am attaching a schematic of my PS which should allow me to continue to supply my 4x6sn7 Aikido preamp with the 40mA it requires, leaving an optimistic 100mA for the output stage, given my transformer is rated at 150mA, and is capacitor loaded. Furthermore, it has a 5A 6.3V secondary, which should be enough for 2 6l6 or ECC99 tubes.

I have modeled the PS in PSUDII, and my voltages are somewhat higher than estimated, probably due in part to my house supply frequently surpassing 121V. Using the software, I have determined that as it is shown gives me 390V with a 40mA load and 4uV ripple, and at 150mA, voltage dips to 340V and 15uV ripple. This seems pretty good to me.

Would you be kind enough to look at my load lines and offer advice on which will likely be a better fit given the PS limitations. I should add that I am not intent on squeezing as much wattage as possible from this amp, and I plan to listen only at modest levels close to the speakers, which are relatively efficient. With this in mind, preserving the character of the preamp (low distortion) is preferable. Another thing I should mention is that the Aikido gives a voltage gain of 9. I plan to use it with a CD player that quotes its output at 2Vrms. Given these, I calculate that I might have max voltage to the output of +-25Vp-p.d My choice of grid swing reflects this, and with the ECC99, I realize that I will not be using the full output of the preamp. 25 V seems really high to me, am I figuring that correctly or is that too literal?

I realize there are many details I have neglected, but thanks for any help with this.

I am not going to profess to being an expert or anything when it comes to electronics or especially audio circuitry, so I was hoping to get some feedback and/or that some people more knowledgeable than I would "check my homework", so to speak.

Here is the current draft of a schematic on which I am working, based on the examples in the datasheets for the LM1875, LM1876, and LM3886; Scott Campbell's "A Complete Guide to Design and Build a Hi-Fi LM3886 Amplifier"; and various information gleamed from this forum, particularly the advice of AndrewT.

I have tentatively selected the LM1875 (for its low distortion) — though it is otherwise a bit of an overkill, as I do not anticipate ever exceeding 2～4W.

Bipolar capacitors are film (my best guess as to what AndrewT meant by "MKP"), the polarized ones are audio-grade electrolytics, and the resistors are metal film (preferably with ≦0.5% tolerance — though that is my own preference).

I explain my high-band/low-band cutoffs in grey near their applicable parts in the schematic. Mouser was referenced for a rough idea of cost and availability of less common sizes. (9.98kΩ, for example.)

Source will be a computer's line-out, so I am guessing that a 10kΩ input impedance would be optimal, and a gain of 10 or 11 should more than suffice. (Also should help with reducing Johnson–Nyquist noise, compared to the values used in the datasheet, per my understanding.)

Question #1:
From a theoretical standpoint, does anyone see anything wrong with my numbers, or am I on the right track? Is anything absent that I should add?

Question #2:
In the case of a pure DC voltage source (batteries, for example), C3, C4, C6, and C7 are unnecessary, no? To the extent of my understanding, their purpose is to "fill the void" between peaks of one polarity of the AC voltage swing, no? Therefore, with a steady DC source, unnecessary, no? (There is also a discrepancy in the datasheet regarding the size of C6 and C7, with the typical application schematic saying 100μF and the recommended board layout showing 1000μF... And I also see people on here adding a third...)

Question #3:
I have seen suggestions of using large polarized capacitors in series with the speaker, as a means to protect it in the event of catastrophic failure of the LM1875. However, such nullifies the advantage of the split supply, no? (Perhaps a reason to opt for the LM1876, instead, I wonder?)

Question #4:
For the sake of breaking free of the two-layered, two-dimensional constraints of a PCB and minimize traces between components (with placement not addressed in the above schematic), would it not make sense to build something like this in free-form/dead-bug style?

Hello to the Forum


I own this little good sounding Cyrus Q Power amp that I used for a while as a power stage for my TV. This amp is just intended for high quality AV systems since it has an auto power feature.
Now I've moved it to a music only desktop setup that I mainly use during working hours at very (very) low levels. Unfortunately when using it in this way it sometimes switches to standby and it needs me to slightly raise the input level or press the front power button to awake it back. The auto-poweroff input level is a bit lower than the auto-poweron (hysteresis), most probably in order to avoid continuos power cycles.


Does someone know if and how the circuit can be modified in order to disable the auto-power feature? I have jut verified that keeping the power button always pressed does not keep it always-on; the auto-poweroff has precedence. The button can only awake the amp if already in standby.


Cheers


Raf

So I've built some cheapo party / garage speakers! Cheap, big, and loud were the design goals, and after hearing the woofer run full range I think I'm on the road to success. The box is together, but I still need the crossover. So here I am looking for help. 😀

Here's what I got:
A big, cheap, MCM 12" part no. 55-1745
12'' Professional Woofer | MCM Audio Select | 55-1745 (551745)
Claims response out to 4.5 khz

Cheapish Pyle compression driver
Tweeter Titanium Horn Driver Threaded Compression 150w RMS | Pyle | PDS221
Fs 800 hz (claimed)

I haven't found any frequency response graphs for these inexpensive drivers. I don't have frequency response measuring stuff, though I can do an impedance sweep.

Dayton 10" waveguide for the pyle
Parts-Express.com:*Dayton H10RW 10" Round Waveguide 1" Threaded | horn lens horn tweeter horn bell horn compression driver DaytonAudioWaveguides070109
loads down to 1,600 hz.

My simplistic plan at this point is to hear from some one what kind of acoustic slope is going to come out of the tweeter / WG combo, then add maybe 2nd order electrical (prolly around that 1.6 khz from the WG) to keep me from toasting the tweeters. Then whatever would match that on the woofer. Plus impedance compensation. BSC will be considered after the woofer and tweeter are playing nicely together.

But this is the first pair of speakers I've built w/o someone else's plan to follow, so maybe someone else will have a better idea. Whadya think?

Is anyone familiar with the transformers on ebay listed as Finemet? They say they were sold through Noguchi in the past. JELabs mentions the Noguchi ones on his blog. But I haven't seen anything else on them and the ebay ones seem like more recent arrivals.

On the data sheet what do the different frequencies next to the primary resistance mean? does that mean it bottoms out at 60Hz on the 5K taps?

I 0nly find sheets that are in some foreign language I can´t read.
Anyone have one in english?

Has anyone purchased any Kartesian drivers recently or dealt with THLP? I've been trying to create an account at THLP and can't get past the confirmation.

Both the Wom120_vMS and Mid120_vHE look very interesting to me as midranges covering, say, 400 Hz to 3k.

Hi folks, I’m Duane and I’m about to put together my first set of open baffle speakers. These will be used mostly for some classic jazz and acoustic guitar music and played at low-medium volume.

Baffles are from an old oak table that’s 1-3/4” thick and it measured 48”x30”. I’ve cut it diagonally and the two pieces are 20” at the base and 10” up top - sort of triangular. I have already cut holes for woofers 18” up from the bottom and chamfered the back sides of the holes with a generous half-round radius. That oak table was a curb find from 30 years ago, BTW, and I’ve wanted to do something fun with it. Now’s the time.

What I’m wanting to do is use a pair of 12” Cerwin-Vega woofers I picked up (also free, off a curb) which I re-foamed, along with a pair of Dayton PS220-8 “point-source” full-range drivers. I was planning on running the PS220 drivers straight from the amp - but limiting the upper response of the 4 ohm Cerwin-Vegas.

Sadly, I don’t have a low power SET or similarly low power SS amp; I’ll be trying these out with an old monster, Krell KSA-100 - until I can pick up something more suitable. Another issue for me is that these speakers will go in front of a large living room with a ceiling peak of 26’. Not sure if that will be a problem. I can get the speakers about 3’ out from the wall without the wife getting too upset.

Can anyone suggest a simple to build low-pass filter that may work OK with the 12” woofers I have and cross smoothly to those Dayton PS220’s?

Thanks for your help. 🙂

All reasonable offers considered when buying in bulk.

The following 4 boards from Ableconn for Raspberry Pi:

1.Raspberry Pi USB to 4 Ports USB Power Hun Board. Jumper selection either 2 pin external 5V or Pi USB power. This is a hat with standoff mounting hardware. Retail $28. Asking $10

2. Pi USB to SATA converter board. SATA III, II or I device. USB micro-B and USB 5 pin header. Retail $25. Asking $8

3. Pi USB to M.2 SATA SSD Converter. Accepts 2280, 2260, 2242 ans 2230 SSD. micro-B and USB 5 pin header. Standoff hardware included for Pi. Retail $25. Asking $9.

4. Pi USB to mSATA. SATA I, II, III SSD. Pi or external 5V jumper. Retail $27. Asking $10.


If you want all 4 boards I'll consider a discount.


TP-Link TL-POE150S POE injector. New in Box. These are $17 with free Amazon Prime shipping. Asking $10 with free media mail shipping.

The 2 units listed below sold together. This will power the DigiAmp+ and Pi to power Passive speakers using DietPi, Volumio or m00de Audio. Great for a small bedroom, hallway or kids room system.

2a. IQ Audio PiDigiAmp+ Specs: Access Denied New in Box with pigtail for external power.

2b .Meanwell brick power supply GSM60B18-P1J. 18V 3.3amp output. Good for small Class D amps. 2.1x5.5 center positive. New in box

Asking $55 for both with shipping included and no PayPal fees.

--- Power supplies. All new in box.

Cosel PBA75F: 75 watt 15V 5A. MFG part number PBA75F-15 Purchased directly from mouser: https://www.mouser.com/ProductDetail/Cosel/PBA75F-15-G?qs=7%2B9h8EK%2Bkysa4hy3GMwxYg==

Only asking $28 with free shipping.

https://www.mouser.com/productdetail/mean-well/rs-75-12?qs=pqZ7J9Gt/mo1O2E%2b2%2byO/g== $15 with free shipping.

-- Meanwell RS-50-12. Link: https://www.arrow.com/en/products/rs-50-12/mean-well-enterprises $12 free shipping.



-- Meanwell RS-75-12 12 Volt 6 amp power supply. Link

Looking for a pair of LL1692A or LL1660, 18ma or 25ma.

Hi, I recently came upon this thread
Ribbon mic (DIY) - Bigger gap to shorten front to back path. | GroupDIY
where PRR mentioned that the magnetic strength of a ribbon mic can affect whether it is resistance driven or mass driven. But it was my understanding that magnetic strength only affects the sensitivity.

If X amps are being run through Y magnetic field, the effect on the ribbon should be the same regardless of X and Y as long as X is sufficient.

So why did PRR say that the magnetic field can negate the effect of mass on a ribbon?

I have decided to clean out my workshop and sell a lot of drivers, amp parts and eventually my tube collection. I have way too much stuff and after suffering a stroke in February my life is going in a different direction. Time to make space for new projects.
I am open to offers as long as they are reasonable. I have used my meter on all of the drivers to verify they are good.

1. Tangband W5-704s pair minor use
2. Tangband W5-704d pair minor use
3. Tangband W6-789e pair new in box never use
4. Vifa DQ25SC16-04 pair brand new no use
5. Fostex FT207D minimal use
6. JBL LE20-1 I have 3 salvaged from various speakers
7. JBL LE10a pair one has a small water stain on the cone
8. JBL LE 5-2 pair in nice condition
9. JBL 123A-3 I have 3 in good condition
10. Dayton RSS315HF-4 rand new never used
11. JBL LE14a pair in nice condition in nice cabinets if you want them
12. Hammond 1620 PP output transformers pair
13. Hammond 166L5 pair brand new in box
14. Hammond 166G30 brand new in box
15. LM3886 amp board stuffed brand new never used
16. 41hz amp6 kit brand new never assembled
17. Bash 300S subwoofer plate amp in great shape

Make me offers. Just be reasonable. Buyer pays shipping.
I have pictures of everything. I will send pics upon request.

I have been wondering for some time about adding or making my speakers 3 way. First off I am running JBL D130's with LE175 horns and drivers referred to as potato mashers. My crossovers are JBL N1200.

I built these in the mid 80's I think my crossovers were beginning to get tired, They have the old paper and wax cap's and they were sounding muddy and I purchased some inexpensive 2way crossovers from amazon and it seemed to bring these speakers back to life. Blew me away how much better they sounded, which brings me to this.

I was thinking about buying new tweeters and use the LE175's as midranges and getting new 3 way crossovers. Ideas or suggestions. I will probably try to rebuild my JBL N1200's and maybe just leave it at is if rebuilding makes them sound as good as it does now with the cheap 2 way crossovers. I know the N1200 are completely filled with wax, and would like suggestions on getting them apart

Rocky

Hi, Im new here and Im here looking for a little help. I recently acquired some lovely vintage Toshiba 330 Hi Fi components. I have the sc-330 amp and matching tuner and pre amp. Iv been using them every day. They look and sound amazing! I have the sytem driving some lovely old Wharfdale E30 speakers.

The whole system belonged to my girlfriends dad who passed away a few years ago so they have sentimental value to her.

Yesterday was listening to some music when I the amp developed an awful static sound - something akin the sound of a Vinyl record in between songs, coming from the left channel.

I have tried removing everything that was plugged into the line in's, fiddling with all the switches on the amp and pre amp, making sure all the speaker cables are attached properly and unplugging all other electrical devices int he room all to no avail.
Also I tried headphones and the static is evident in the same channel through these too.

I would like with your help and advice to perhaps attempt a repair. I have only a very basic understanding of electronics but I probably know more than your average man on the street.
People have suggested contact cleaner for all the pots and switched so Iv ordered some from ebay and Il try this first.

If you have any information or input Id love to hear from you.

There is a post from a guy with the exact same amp and what seems to be a similar issue on another forum. The thread ends without an outcome but non the less it may be of use to someone offering help to me, so here is link:
Toshiba 330 Rack - Tapeheads.Net

any help much appreciated.

Thanks 🙂

Hello, first post here.
I am considering building a sub with a Pioneer TS-W312D4 as the driver for home theater. I cant understand how to build the port or the total enclosure volume through WinISD ; by trying changing values of the tuning frequency it is giving me the proper response in the Transfer Function Magnitude, but I cant figure out what structure needs to be changed to reach the lowest frequency in about 15-20Hz with the highest SPL possible?

I'm looking to make myself a set of "mix cube" type studio monitors. Typically known for being single-driver, sealed, and light on bass/treble so one can focus on mixing midrange content. Most attempts to clone the prototypical Auratones end with the need to find an identical driver. I'm not interested in a clone, just making a small, sealed, let's say "mid-focussed" speaker from a full range (or I guess good mid range) speaker driver as a complement to my "big" monitors. I actually already made a prototype with a $1.95 speaker from a DIY electronics site in a 3D printed enclosure. It's a bit to distorted at low volumes to be the finish line but it was close enough to make me think a real swing is worth the time.

So, I'm looking for driver options. Right now the best looking driver I've found is the Audax 13LB25AL with its flat midrange and gradual role off in a small sealed enclosure. The sensitivity is a bonus too. I also have a pair of Mark Audio Alpair 10p but they look to need a bigger sealed box to prevent a bass bump from over damping. The smaller alpairs all look to have a little bit of a scoop in the mids that would be undesirable. Surely there are other choices if anyone can make a recommendation. I'd pay about $150/driver max or thereabouts.

Hi guys
I am recapping my mark levinson 33H
As I star with the output stage board I have looked for week links
I wish to upgrade the emmiter resistors to non inductive and non magnetic ones and if it's possible to ultra low noise ones.
I don't have any experience in this specific point of upgrade so I don't
Know what to expect by sound characters.
I have heard great things about vishay mils resistors and ohmite audio gold resistors.
Did any one compare between those 2 ones ?
What are the sound characters did you got by upgrading emmiter resistors?
Values that I need are:
0.22 ohm 5w now installed cw5 resistors)
0.33 ohm 10w (now installed cw10 resistors)
10 ohm 5w (now installed vishay NS-5 non inductive)

Best regards

Nehoray

During installation a small piece of wire fell into the amp (the rca side). After that all 4 leds light, and consumption is 250mA at 12V.
A local technician tried to repair it and replaced R30 with a 2K2.
Then they send it to my shop.
I removed the transistor switch of the power supply driver board, injected 12V, and managed to turn on the power supply. The audio section has no rail to rail oscillation, probably muted.
Any help is highly appreciated as the amp seems quite complex.
I dont think the class D audio section is faulty, i believe its the turn circuitry.

Same of us experiences really hot summer know and miniDSP 2x4 HD

runs quite hot.
If you have a 3D printer welcome to print vented shell.
www.thingiverse.com/thing:4902183


I have added fans for vented shell as well
www.thingiverse.com/thing:4912339

this Focal Solid 1 is stuck in protection .there are no bad psu or output transistors ,no dc on the speaker terminals .nothing appears burned
Pwm is tl494cn

Pin 1:0.00
Pin 2: 1.35
Pin 3: 0.07
Pin 4: 1.53
Pin 5: 0.21
Pin 6: 0.45
Pin 7: 0.00
Pin 8: 13.97
Pin 9: 0.00
Pin 10: 0.00
Pin 11: 13.98
Pin 12: 13.98
Pin 13: 1.55
Pin 14: 1.55
Pin 15: 1.55
Pin 16: 0.00

hi- pressure pad has disintergrated- wondering what to replace it with

Hi amigos,

I don't know if you've heard of the Poppulse T180, in its MD version for the German market. But I was lucky to be able to have one)
The MD version was specially made for the German market with best caps and some improvements (wiring, OP amps etc).

I discovered this amp on a German discussion thread and was very skeptical of its praise. This amp has been compared to many amps above the 10,000 euro mark, including the ASR Emitter 2.

I am one of the people who prefer to test rather than read too much .... I am quite pragmatic in my approach so here is a small review of this beautiful amp

You can see my reviews from ASR and Diyaudio, I own many amps : Purifi / Hypex Ncore / Dual Merus Infineon / Top level TPA3255 etc...
So I have a good basis to be able to compare this Poppulse)



Spec :

Poppulse T180 MD version
Dual Mono Tripath TA2022 chip
Update : OPA1656 for Output path (XLR) + OPA1692 for the preamp section
Linear PSU
Full Balanced inputs
Unbalanced inputs
ALPS motorized volume controller
Anti RFI/RMI filter
2x120W / 8R
Full aluminium case
412 x 340 x 80 mm
8 KG

My setup :

Gustard AK4499 Dac (full balanced)
HD Audio stream source
DACS 33 floor speakers with Ribbon Tweeter 3 way


The amp already seems very well built and robust, it is quite heavy given its toroidal power supply (8KG). It is assembled in a black aluminum case and the connectors are of good quality.
By opening the case we discover a fairly simple but very clean circuit which highlights the two Tripath chips in a dual Mono configuration, so one chip per channel. Basically it comes with two genuine OP5532 that I updated.
Everything is well made in and it's readable enough to understand that we are dealing with a well finished amp. In this price range it is also very rare to find a motorized volume controller, the amplifier comes with a small remote control.

I have a small downside concerning the automatic protection mode: indeed a chip resets the volume controller to 0 each time the amplifier is turned on.
But in the end it may be a good point to protect the speakers
The manufacturer recommends a 40-hour break-in to polarize the components; I am still far from it because I barely did ten hours of listening.

I listened to multi styles in HD Audio to see the potential of the amp and I can already tell you that the amp has enormous potential!
You have the option of bypassing the internal preamp via two small switches. (bypass preamp 0db or use preamp 12db)

I made the test with the preamp only for the moment. The OPA1692 update on the preamp section allowed me to considerably improve the soundstage and refine the highs.

Here is my feeling:

Highs :

Tripath is well known for its definition, especially at the top of the spectrum. On my jazz register, the ride "chabadas" are sublime! The hi-hat, cymbals and effect cymbals come out beautifully and the Tripath / Ribbon Tweeter combination works wonderfully.
The higher-pitched voices come out extremely well in the mix in most of the albums listened to and the amp is in no way aggressive in the treble, the listening is very musical and muffled.

Mediums :

With the OPA1656 the mids are straight and very neutral. Compared to the 5532, I found that the OPA1656 brought a lot more warmth and "naturalness" to the vocals.
Here we keep the analytical dimension of class D with the advantages of class AB.
all the voices come out wonderfully, the baritone, soprano and tenor are really well transcribed.

Bass :

I never liked amps with bass transcribed too far forward. Here the bass is balanced, fair and round as it should. in the Pop to Rock register, it's clean and it doesn't bleed.
The delicate bass acoustic articulations are reproduced very well. I refer in particular to the mix in the rhythm section double bass / drums which stands out to me in the Jazz register.

Conclusion :

I was very skeptical when I read the German forums. But I can tell you that this amp is a killer considering its price. I was able to compare it to my Dual Merus reviewed recently on ASR and even against my Purifi, this amp is probably the most "musical" of the class D that I have been able to test. It is silent, very dynamic and absolutely warm in all registers.
This amp has everything a big one, a huge soundstage, enough power to drive big speakers and above all flexible with the possibility of personalizing your sound with your favorite OP amps in DIP8 format and even the possibility to bypass the internal preamp.

I have not tested the ASR Emitter 2 highlighted on the German forum (Kellerkind-Audioforum - "MD"- PopPulse T180) and which has been compared to this Poppulse but in my humble opinion this amp will overshadow much more expensive amps. I had the pleasure of testing a bunch of amps much much more expensive but really less efficient than this Poppulse! If you find one, go for it!

Demo Video :

In progress. Will share later

Pictures :



envoyer des photos gratuitement par internet








envoyer des photos gratuitement par internet

envoyer des photos gratuitement par internet

Hi all
Amp using 4 transformers using 4 set of IRFP064N mosfets. The driver transistors are KTN2222A and KTN2907A.

I would like to know the good replacement for driver transistors. Thank you.

Good day/night to you all! I've been thinking of building a pair of CHN-50 enclosures to use for my desktop setup, now that I'm hooked on MarkAudio from my 7MS build.

After looking through all the vented and mass loaded and horn designs, I simply don't know the advantages and disadvantages to each within the context of my particular setup...

Being that they will be on a desk, they will be both near the rear wall of my room, and each speaker will be sharing "baffle" with part of the computer monitor to the left and right.

Quite a loaded question, but what would be the sonic advantages in this use case to going with a horn loaded design, versus simple vented or mass loaded, other than taking advantage of getting the drivers higher and closer to ear-height when sitting on the desk?

Does it even matter? If not, might as well go with a Tozzi One kit? That'll save me time and effort.

I appreciate your insights. 🙂

Hi,

I have a brand new Hypex NC502MP module + cable kit to sell
Free shipment to Europe, can't ship outside !

Last version (2021).

Perfect to build a clean reliable powerful amp.
See ASR to check the NC502MP great performances )

PRICE : 450 euros free shipping (but UK)
Paypal only please


Hypex NCore NC502MP twin Channel Module
PSU SMPS integradted 1500W
Auto sensing 100-240V mains input operation
0.5W standby operation
47K Ohms Input Impedance, low output impedance
THD 0.0018%
S/N Ratio 116dB
26dB Voltage Gain
2 x 350W 8 Ohms
2 x 500W 4 Ohms
2 x 450W 2 Ohms
Fully loaded flat frequency response
92% efficient

Two years ago i purchessed a broken DD Dual turntable for its tonearm which was in good condition. I also have a B&O MMC20E cart that was never used from a broken B&O turntable , some Easton archery Jazz arrows made out of 7075 aerospace alloy and a a broken Garrard whose counterweight needed to be used too...Now i need to wire it , put the phono pre inside the wooden box and listen to the damn thing.

I'm tired of designing in high voltage and having a lot of spares and components. My method will help get the best performance. I hope those who believe in me will receive good things. when building a class d filterless high voltage system.
[double H Bridge]
[Sorry, the circuit I posted still crashes.]

Hello there!

I am a member on this forum for quite some time now. I just thought it would be great to introduce myself. 😀

I started building my own radio when I was ten. My father is an electrician and he always collects electronic boards from garbage(I came from a poor family). One day I found this fm tuner board and an amplifier board from a toy piano, with the help of my dad, I have built my first fm radio. Since then I fell in love with building audio electronics.

I am now an electronics engineer for more than 10years. Sadly I didn't got any opportunity to work for an audio electronics design job. But at least I am working for research and development for electronic products which is still I love.

I have created a website tataylino.com to post some of my work during my free time. Most of my post there is about audio electronics. This is my way of continuing my passion in audio electronics since my day job is not about audio electronics.

Cheers,
Glenn

I would like to share my DIY turntable plinths with you

I refer to the thread title which is IMO inaccurate. If accuracy in knowledge is required, to visit this set of forum pages then we should know firstly what analog line level is, and what equipment analog line level actually relates to. Our sub list of equipment presently reading as Preamplifiers , Passive Pre-amps, Crossovers, etc.

Will after a few pages here hopefully be seen to be quite inaccurate, and collectively be asked to aspire to greater accuracy to assert the pages knowing what line level actually is and only include equipment in discussion that actually uses Analog Line level.

As example would if we adopt the AES guidelines, would include as well as consumer line level and professional level equipment, also microphones and musical instruments.


Can we have firstly perhaps seek consensus on the definition of Analog line level

1. Consumer line level, can we agree this is the majority of audio equipment forum
members use.

expressed as -10dBv or nominal level 0.316V
RMS , or Peak amplitude V pk 0.447v or Vpp 0.894 ,

2.Professional equipment expressed as +4dBU , or nominal level 1.228V RMS
Peak amplitude Vpk 1.736 or Vpp 3,472

We should find in our understanding that consumer line level is bound already to the manufacture of CD's DVD's and the same same standards are used by streaming services. historically there was break away from this called the Loudness wars, but was sensibly brought back into line, when someone woke up that, dynamics were unable to be reproduced. ( this does not discount the inevitable use of companding that awaits )

Professional level is different in that DAW's and the like are constantly trying to achieve as high a dynamic range as possible at the recording stage,( Companding is the answer for everyone ) however professional level still applies to equipment in recording studios, and some equipment that can be used in domestic settings, but is typically balanced audio, and may have much incompatibility if used with consumer line level.


as a reference the AES ( Audio engineering society ) define line level here:
Pro Audio Reference (L)

"levels Terms used to describe relative audio signal levels: (Also see decibel).
mic-level Nominal signal coming directly from a microphone (before any digital conversion if present). Very low, in the microvolts, and requires a preamp with at least 60 dB gain before using with any line-level equipment.

line-level Standard +4 dBu (pro) or -10 dBV (consumer) audio levels. See decibel.

Instrument-level Nominal signal from musical instruments using electrical pick-ups. Varies widely, from very low mic-levels to quite large line-levels.'


There is scope already for DAC's to have amplification stages in them altering line level ... but this I invite blurs discussion of analog line level itself , if we base ourselves on accuracy going forward.

Over to you.

Hi folks


My Apart Concept1 amp started sounding distorted a couple of weeks ago, so I replaced all the large electrolytics and it cured the issue, I suspect the three caps next to the voltage regulator heatsinks had dried out.

However, there is still a problem, the amp has four inputs labelled A, B, C & D. It works great on B, C & D but A sounds distorted.

I also changed the 2.2uF electrolytic caps on the inputs to 2.2uF polyester ones, I don't have a service manual or a schematic, otherwise I'd replace all the caps in the signal path.

So, anyone got any bright ideas as to how to diagnose and fix input A? The only thing I can think of is to trace the channel from the input jacks, replacing all the caps along the way. However, I'm dubious that just a change of caps will do the job as the other 3 channels sound fine.

Just got my hand on a Thorens TD 160 and need to get a phono stage for it. If you have one for sale or thinking selling feel free to ping me.

I have installed bookshelfs with empty space in the corner (IKEA Billy). I have room for some absobers of some kind. From the corner out to the back of the bookshelf set at 45 degree angle from the walls there is about 35 cm distance. There is room for both some fibrous damping material and 25 cm/10" pipes.

The easy way out would be to stuff the whole compartment with some fiber material. An other would be to utilize a part of the space for quarter wave traps. Is that useful for say the 100-150 Hz range? If so should the open ends be placed near the corners (pressure maxima) or away from the (higher velocity)?

Hi,
I need some help.
I have a 1200AS2 module that stopped working.
Auxiliary and stby switching PSU is trying to start but after less than a second stop. That is all that I've found out without schematic. No visual demage is present on the board.
Is here anybody who has any experience in repairing this modules or has a service documentation to share?

I was lucky enough to be gifted some transformers at a time when I was wishing to experiment with some saturation ideas.
I made a video going through the stuff and there are some pretty interring items we found.
Let me know if any info in this video is incorrect or have any ideas for things I could do with these transformers.

Transformer MOTHERLOAD! - YouTube

Hi, I need some help. I have done some research but still can't find enough information about this Sprague 25uF 0-25VDC axial capacitor.

It looks like it needs to be replaced. Any suggestion is most welcome.

🙂🙂🙂

Mod note:

This thread has been split from Simple DSD SRC for BeagleBone

ppy said:

This project has been completed. Sound quality is quite high.

I offer two options:

1. For DSC 2.6.2 + U.FL output.
2. For DSC 2.5.2

The firmware Pure is compatible with BeagleBone Black, BeagleBone Green, and AntMiner.

Complete set of documentation for self production.
DSD`it — Yandex.Disk

Click to expand...

If Pavel has no objections, I am considering running a small quantity group buy for assembled boards. I have a friend who can do the smd soldering (using a reflow oven) for a reasonable cost. Is there any interest? If so I'll explore the costs a bit further.

DSC04869

Hi all, this old thing has been in storage for a while. Mostly works, most faders need replacing. Rca inputs noisy and headphones pretty ordinary

1 - is this junk?

2 - worth rebuilding to reasonable levels for a lotsa channel spare? It will be used for micing drums for now if rebuilt vs buying a small semi decent like a Yamaha

3 - I am attracted to the idea that if this unit can be used as a solid platform for something decent diy. The chassis seems solid and in good condition as are all the sockets. Would this be able to accommodate passive point to point type level, tone, pan and routing per strip preserving the channel strip functioning? Would this have enough space to fit a final valve based summing, gain and headphones? Instruments will plug in through pedals or already be hot

An attraction of building a valve gain in the mixer is to use it as a possible line conditioning stage (tube sound like that old musical fidelity x-ting) by plugging the music/karaoke pc into this then on to the power amps.

Also attracted to the idea of adding a mic at a time with each on its own outboard preamp maybe tube or jfet (wonder if this has the space inside to build simple jfet gain for each channel, I can lift the unit by adding more body underneath by about two cm or even more at the rear. Maybe homemade wedge or L shape custom end plates and backs. I can can give up the wide flat areas around the meters for things like tubes sticking out

It will be nice to have a simple, robust but musical setup where we just plug in our headphones and or music making things and jam or sit back or turn the amp and sub on

Through-hole 1% non-magnetic metal film resistors are getting hard to come by. And spending a buck a pop for them gets old quick, not really knowing if they're non-magnetic types until you receive them.

Some of you no doubt already know this, but quite a few excellent through-hole passive parts (especially 1% metal-film NM resistors) can be salvaged from 70's- and 80's-era test equipment. Many of these pieces have little or no market value any more and can be picked up for scrap value. It makes a lot of sense for a hobbyist to keep a few pcb's from them in the garage as a source of parts for ongoing projects. Of the major brands, here's a brief list of ones to keep an eye out for.

HP: Anything HP with analog circuitry and made in the USA from say late-70's to late-080's is chock-full of Dale CMF55 non-magentic resistors, with a sprinkling of RN60 to RN70s when needed. Typically hundreds of them per unit. After that they moved more to Roderstein (which are magnetic) and then to surface mount. Units made in Germany use mostly Rodersteins.

Most of HP's axial film caps were made by TRW, which tend to be very good. Most radials are Wima.

Wavetek: Wavetek function generators used TRW RN55's exclusively, all of them non-magnetic and excellent.

Tektronix: Old Tek stuff is more hit and miss. They used a variety of vendors for metal films, some magnetic, some not. I don't tend to save Tek pcb's for parts.

Interstate Electronics: A bit of a sleeper. These guys used very high-quality parts throughout. I just scrapped one of their P25 pulse generators; it has 140-150 Dale RN60 NM's on the main pcb. Nice heatsinks too.

Generally, any piece of gear for which DOD or DOE was the primary customer probably has high-quality passive parts inside.

Ones to avoid:
Systron Donner. Not worth the trouble, IMO.
Fluke. Their precision resistors were nice, but their general-purpose parts were nothing special.

Feel free to add to the list.

Hello folks, I'm a happy owner of an F4 which I built a few years ago. I really dig it, and I'm using an Audible Illusions M3A preamp.

They sound amazing to me, together, but even if the M3A is well known for its high ouput, it still isn't quite enough to express the full potential of the F4. I find myself turning the knobs full clockwise, and sometimes it just isn't "enough", or other times it makes the preamp itself distort a bit too much. I'm a bit sad, because I really like it, but it just isn't as usable as I'd like...

So, taking advantage of some upcoming spare time, I'd be willing to build an adequate preamp to drive the F4 at its full potential.

I've done some research but I'm not sure, and I've been a bit out of the scene in the last couple years, and that doesn't help either; it looks to me like the Pumpkin Preamp is the best shot. Is that so, or are there any other serious competitors, well suited for an F4?

Price is a bit of an object here, but I don't want anything that will make me miss the Audible Illusions... So, I just want to build something good. I hope it's possible to find a project which is both good sounding and easy to put together...

Thank you in advance for your help 😉

Giacomo

i have some questions here ... my previous experiment using test box running for 4th order bandpass subwoofer seems have found the optimum box volume and also the tuning frequency

Now time to the actual build ... i wanted something for my 4th order bandpass subwoofer with Plexiglas acrylic style on the sealed side of the bandpass so i can view the woofer from the outside at the same time adding some WS2812B running colour LED to make it nice

the plexiglas acrylic i found local here was 10mm thickness the thickest i could find ... is that thick enough? Only the removable panel to the driver access was plexiglas. thanks

I finally found one of my grail DACs. The price is good, not great (it's for sale by a dealer). Question: being from the 1990s, is it good to listen to as-is or should it be re-capped?

Hello All,

This is my first time posting and my first amp build. I'd appreciate some feedback even though I can eventually sort this out. I'd like to do further research but am limited in time due to family commitments and work. Once completed, I'd be happy to write it all up for the community. The customer support from Ghent has been helpful.

I'm building a monoblock amp to power a subwoofer. I have purchased the ICEPOWER 1000ASP board and the Ghent GK-ASP-MXR case. I chose the case with both the XLR and RCA to have flexibility in future stereo endeavors. However, if that imposes a lot of trouble, I'd be okay with just hooking up the RCA for now.

Here are my questions:

1. Ghent also sells an RTX module that converts an RCA input (+/GND) into balanced signals(+/-/GND). I'll be starting with an RCA input and possibly switching to XLR down the road. Do you all recommend the RTX module? This is only a subwoofer so I'm thinking the loss of quality may not be unacceptable.

2. If I choose not to use the RTX module and just do RCA only, would I just connect the board + signal input (P2) to the XLR connector, and buy an XLR to RCA converter cord?

3. From the AC connector (P3), I appear to have an extra black lead for the ground wire. I thought it would cut off the connector and attach it to the case ground screw just to add extra assurance the board is well-grounded. Any input?

4. When I do go to test, what do you all recommend for safety if I have to open it up again? How much time might be needed for the capacitors to discharge? A week?


For reference, the amp board data sheet is here:
https://www.parts-express.com/pedoc...asp-class-d-amp-module-1x1000w-data-sheet.pdf

(page 5 displays the pin connections)

Thank you!

This project has been simmering on the back burner for the better part of two years, but today I finally made some tangible steps towards what will be my most ambitious tube project to date: a 100 watt OTL loosely based on the Alan Kimmel circlotron that appeared in Vacuum Tube Valley: Issue 8.

Due to the cost and complexity of the build, I'm trying to approach it with a modular build style. This should allow me to build functional blocks at my convenience without having to commit to buying/building all the parts at once. My first step out of the prototype stage has been the output-section block, which is pictured below. The PCB was designed in Eagle and the aluminum socket plate was ordered from SendCutSend.

The OTL is built around the 21LG6A sweep tube. I found through some research that this tube offered a great balance of maximum current delivery at an affordable price. Far more economical than EL509 or the pricey 6LF6, especially at a quantity of 10 per channel. The driver for the output tube banks is borrowed from Pete Millett's A2 Driver Board and the preamp section is high gain "super triode" configuration leading into a LTP phase splitter.

I have a long road ahead on this project, but for the sake of documentation I will try to update this thread as I make progress. I appreciate any feedback or suggestions as I am very much an amateur and not an EE by trade.

Is there anything wrong with taking the first stage feedback signal from the same point as the input to the active Bax tone circuit like this? Would I be better off to take the first stage FB right from the anode? The concern is interaction between the two stages.

Hi folks,
Has anybody tried out the 814 pentode as triode ?
There are very nice curves on Pete Millet's site: http://www.tubebooks.org/file_downloads/814%20curves.gif

Thing is, anode voltage (and thus G2 voltage) goes well beyound 1kV. Furthermore the drawed Operating Point is at about 700V.
But: In the Datasheet they give a max. of 400V Ug2.
The reason might be that the datasheet only gives RF operating data. Max Ug2 for AF operating is usually much higher. But I'm still in doubt. Anyone has some facts ?

Hello,

I have a lot of questions.

Reference:
I want to build a two way DIY Klangfilm Eurodyn speakers. See attached photos.

Gear:
I have a pair of EV DH1A drivers.
Specs: http://www.electrovoice.com/downloadfile.php?i=971741

I'm planning on buying a pair of tractrix horns from stereo-lab.de:
http://stereo-lab.de/Horn-cf-450-Hz...uency-spherical-wave-tractrix-waveguide-lense

Im uncertain of which 12"/15" woofer that suits this setup - it needs to be a woofer that is buildt for being used in open baffle constructions.

Reason of choise:
I want this setup to be more integrated in my apartment than previous hifi solutions - the WAF, but still a sound I will find intriguing.

My plan ( with a lot of holes )
See attached renders and digital drawings.
I want a passive dividing network for this two-way setup.

I want the rear panel ,of the two single constructions , to get the lower frequencies to play - I have been told I will need a channel between the front panel ( placement of woofer ) to the rear panel + a opening in the rear panel + a distance from wall and rear panel to get this to work.

I want the speakers to be driven from my current 2a3 tube DIY amp or my Quad II's.

Questions:
1. Which woofer?

2. What type of passive dividing network?

3. How much calculations / simulations has to be done? - asking since I do have very little knowledge on the subject.


All inputs greatly appreciated.

*Edit* No longer discounted.

I just bought an extremely bad shaped Edison One preamp with two Edison 24 mono amps. Just paid $100 for all three. Looks like they have been tampered with by a child, but my hope is to restore and get them to play again. Still waiting to receive them from the Post Office.
I emailed Erik Andersson to ask for schematics but the received answer was NO!


Anyone here or know anyone who has schematics and experience with these?
Thanks in advance.

Hi,
I previously designed an amplifier PCB that included the output relay on the PCB. I want to redesign the board for through hole components, which take more space than the surface mount transistors previously used. The board dimensions need to stay the same to replace the existing board since the heat sink has been drilled etc.

If the relay(s) are off the board, i can reclaim more space for the circuit, and use through hole components, change the relay configuration by design, and also it will be easier for maintenance of any failed relay.

Does anyone have a preferred option, as off board protection relays offer greater flexibility for very little degradation, if any, for on board relays.

Thanks and regards,
Shadders.

Hi folks


I just obtained a pair of the AMaudio boards to build a phono preamp.
Unfortunately no schematic or list of parts appears to be available, I've checked their website, sent an email (which was returned as recipient unknown) so I'm a bit stuck.


The circuit is 'based on' the Boozhound, but is clearly slightly different as it includes a transistor and diode that the Boozhound doesn't.


Can anyone help me with supplying the correct schematic? I don't want to use the one below as it's for the Boozhound and this AMaudio one is slightly different, so I don't know for sure what value corresponds to what resistor - i.e. is R7 a 10ohm resistor on the AMaudio like it is on the Boozhound?

Hello! Maybe someone has a scheme for the below amplifiers:

Professional power amplifier MAX MA-1920
Professional power amplifier D.S.E AB-1800

Thank you

Hello,

- U192ETL USB transport with ElectroTos/Toslink interface and ElectroTos low jitter protocol,
- DA96ETF Discrete, ultra low noise multi-pattern fractal DAC with ElectroTos input.

Info: ECdesigns
Price: sold
Location: UK

Thank you.

[Solved] Audio Research CD2 tray opening issues

I have a Audio Research CD2 player which has a tray opening issue.
Probably just needs some cleaning but I am unsure how, and hoping people could give some pointers.

The issue is that when I press the eject button it might open half way, pause for a second and close again.
Sometimes it will open all the way and close immediately again.
This can happen several times and then it will open and stay open for me to lay in the CD.

Closing is usually OK but can experience funkiness too sometimes.

CD's, when inserted, play just fine. So I am assuming there is some detection thing that needs cleaning, but I don't know where it might be located.

Of course I tried looking it up, but all you get then is using a CD cleaner.
And since the laser doesn't seem to be dirty I doubt (but could be wrong) that is the issue.

Anyway, hoping to be able to use the player again since it's a very nice transport using AES/EBU. Never used the analogue outputs since, till the end of the month, I own a Devialet 400 setup. Switching to a Luxman L-590AX MKII then so would need a new DAC too.

Thanks in advance.

Greetings from Lake Geneva,

First post of a non-techie newbie, I'm interested in giving DIY a try.

I've been searching for some tube amplifier build video series and this is what I found so far:

Blueglow Electronics - Single Ended Amplifier Build 2017
Single Ended Amplifier Build 2017 - YouTube

Blueglow Electronics - KT88 Single Ended Amplifier Build 2018
KT88 Single Ended Amplifier Build 2018 - YouTube

stephe - Skunkie Designs Electronics - KT88 SE DIY Tube Amplifier Build
KT88 SE DIY Tube Amplifier Build - YouTube

stephe - Skunkie Designs Electronics - 6BM8 DIY Stereo Tube Amplifier Build
6BM8 DIY Stereo Tube Amplifier Series - YouTube

stephe - Skunkie Designs Electronics - 300B DIY Budget Tube Amplifier Build
300B DIY Budget Tube Amplifier Build Series - YouTube

xraytonyb - Scratch Build A Stereo Tube Amplifier
https://www.youtube.com/watch?v=egZ-XQ0k6Qo&list=WL&index=9

Young Ahn - Fluxion - How To Build Tube Amplifiers
https://www.youtube.com/watch?v=1N3_x91t-Gg&list=WL&index=17

And a new serie that is just starting, I like this channel:

Real World Audio - Build a SET
https://www.youtube.com/playlist?list=PLe6evB19z4AmC6bcukd9tAlXGYvmSEddn

Are there any other links that you could share?

Thanks,
Joel

Hello!

Thought i should share a small test I did between analog and digital volume reduction. The application applies to active crossover filters. (In other words an extra analog pass trough on all levels vs bit depth loss on lover levels).

The devices I used were Yamaha RXV 800RDS (Amplifier with 6ch analog vol control feature) against Open DRC DA8 (8ch digital crossover with digital vol control) both used the same cabling and and were recorded in Cubase in 24 bits. The audio files were then normalized to make it easier to compare differences in character between all four.




There were small differences in so-called HiFi-friendly music so I chose to continue only with a song that had a more crowded mix. The source was 50sec from an Original CD via S / Pdif. Track used:


NOTE! the test only shows differences not the actual sound because there is an additional AD conversion at the recording plus an extra during playback. The device I recorded with was the Motu UltraLite Pro soundcard.


Part 2.
Most digital volume controls today have 32bit floating point as well as this in the above test. Therefore, it was interesting to see what this means. If the rumors are right, you should have 16 bits extra to trim your volume with before the CD stream losing bit depth.

Lowering via - DCD1290 with internal 16bit digital vol control
Lowering via - Open DRC DA8 vol control with 32 bit floating point enviroment.



Part 3
As a small bonus, I also compared the character between these crossover dac's and a CD-DAC.
Denon DCD1290
Open DRC DA8
DCX2496 (with a French rca mod)




Tip:
It was easiest to hear differences in large headphones, and at best, import the files in Cubase or similar so you can start all at once and use "solo on selection" when switch between the files.

50sec Wavfiles for all test (zip)
https://www.amazon.com/clouddrive/share/I1Eu1znGAPYWgElP1L91AAPoFPebjymtUubS02Bv0k5

Got my hands on a Parasound HCA 1000 Power Amp, but can only find the service manual for the later HCA 1000A. I don't know the difference between these 2 versions, so could someone please guide me with a link to this??

SOLD SOLD SOLD SOLD


I have 2 kits, new in the baggies:

x1 Standard Chipamp LM3875 with standard PS boards

x1 Chipamp LM3874 with the big, beefy caps PS boards.

Take both for $110, no PayPal fees and free shipping.

Extra: for the person who takes both kits off my hands, I'll throw in a free Grayhill rotary selector switch with PCB ($22).

Thank you,

Nick

I am trying to solve the crosstalk problem of a Adcom gfp555ii. Looking at the schematic I found that the circuit board is connected to the chassis via a capacitor but there is a 10 ohm resistor which is connected to no where. Is there anything wrong and is it related to the crosstalk problem, i.e. I can hear the music through Tape In when the cd is connected to the CD input?

I was impressed by the review of this made in China amp where he actually opens it up
for a look inside. How about those 6L6GCs for 15W? Sounds good too:
PRS MT 15 Mark Tremonti Amplifier| An Inside and Out in Depth Review with Playing | Tony Mckenzie - YouTube

This guy measures about 25W:
PRS MT15 - Real Maximum Output Power Measured - YouTube

Perhaps the real Tiny Terror!

Might be good inspiration for a cheap build.

How accurate are the online software calculators for figuring out the components for a parallel notch filter? I have found more than a couple on the net. I'll be working on the 2 to 8Khz range.

I'm trying to tone down the highs on my Frugel-horn Fostex Fe108EZ's. I want to attenuate the range from 2Khz to 8Khz at least 3dB. I would need to buy high-quality capacitors, so buying and trying experimentation would get very expensive very fast.

Any advice or pointers would be greatly appreciated. Thanks.

Doug

I bought a 2.hand.

I want to ask a question, Q155(2SD669)&Q158(2SB649) are very hot. They are 45C after 1,2 min. turn on. Also, they are power supply regulator transistor of somewhere 🙂 I don't know. But, they're not for power amplifier main supply.

In service manuel, in the circuit diagram it's 2sd669 (1.5A transistor), but in part list it's KSC2690AYSTU (1.2A transistor). In amplifier they used KSC2690AYSTU.

Is this normal NAD design (Too hot transistors)???

There is no problem in sound.

If your interested in music production, music theory, or just music, hears a great youtube channel. You don't have to be a musician to appreciate it. The quote in the title is from this video.

Why Don't Record Labels Believe In Young Artists? - YouTube

Looking at toroidal trafos on ebay and an interesting one came up out of an Arcam av receiver. I downloaded the manual and found the trafo windings.

It seems that the main power amp section rails are switchable by a relay. I dont know what controls the relay.

Am I right in my assumptions here.? Looks like it can either run on the 36v or 29v rails.

Why might this be, just out of interest?

Thanks

Would like to swap Baby Huey EL34 PCB for Baby Huey EL84 PCB, or buy BH EL84 PCB, swap for tubes etc etc.

Please PM if you are interested/can assist.

Thanks.

I have tried this schematic (a combination of components of various ZENs) as a preamp for Zen9 and got an unexpected good and powerful sound. The jFET is a russian vertical SIT transistor KP926A with the triode-like output characteristics. Quiescent current is 150 mA, what seems to be crazy for a preamp. Undistorted sinusuidal output voltage is up to 27V, that is good for a power follower.

I purchased a couple of tiny boards based on the PAM8610 chip from Ebay. About $10. I want a tiny amp to feed my portable "Think-Geek" "crystal" speakers.

This chip feeds the class-D switched signal straight to the speakers, without any filtering. I added a few ferrite beads...

Works OK, until you get a transient bass-drum. That sends the amp into fits, with a noise I will describe as a "racous burp." 8W+8W of sine wave at 30Hz is fine, the transient bass is what sends the PAM8610 into fits.

Has anybody any idea where I should be looking to ameliorate the problem. I already have a huge cap on the power rail 🙂 I suspect it is some form of bootstrapping with too lower a capacitor value... has anybody any suggestions?

Hi all.

I fancy giving one of these cheap DACs a try, but I have two OPAMP options. Can anyone help please with regards to the differences? I am looking for a smoother, lusher, organic more euphoric sound then, especially on vocals, and something not over etched digital with less glare then if thats possible between the choice of the two. Any one any ideas to the differences please?

Hope someone can help me choose.


https://www.aliexpress.com/item/1005001966656478.html?spm=a2g0s.8937460.0.0.55012e0efO6PWn

I have some pots/attenuators that I’d like to clear for new projects. All are new, unused.

Noble 10K potentiometer, coming with pre-soldered board. 4 pieces. $59/ea

24-step attenuator. This one has twice the number of resistors (4x24) for a stereo unit. All Vishay Dale resistors. 4 pieces. $35/ea.

Shipping worldwide is $15.

Can someone point me at a supply for the attached hybrid amplifier? Any kits out there that would work well for this design?

I have a pair of tympani iva's which I had planned to use in the new house. It seems though that even in the large main room of the house, they are a bit overwhelming to some...So I am considering using just the mid/tweeter panel, using an ob dipole servo sub (gr research/rhythmic) for the lows. Not sure where the tympani's cross over to the mid panel. Anyone know if this is feasible? If not, any suggestions?

Thanks!