Hi Chaps,

I recently acquired a mint 401 50Hz deck, my third in fifty years. I have a new 60Hz pulley but it has been impossible to loosen up the slotted screws in the old bottom collar, the top collar was easy. I have plenty of screwdrivers but as you can see in the photos they do not fit straight in the slot due to the angle and the tiny screwdrivers do not have the strength to do the job. I do not want to disassemble more parts.

Any suggestions will be greatly appreciated.

Horacio

I have a P1000 that came in For repair due to not producing audio. I took the amp apart and checked the gate of output with my scope and noticed a small square wave was present on pad. I then checked the drain and realized it had 0 volts. I checked the power supply and it is functioning properly with nice square waves on gate and drain. I placed my multimeter probes on the center of the rectifiers and read 0 volts. The outter legs of rectifiers have nice square waves on them. I’ve repaired a couple of these but never seen them without rail voltage.

I bought some binding post with 4,000 crossovers attached. They were so inexpensive that...I can remove the crossover & only use the binding post & I'm still ahead. But...I need a crossover for 2,000 or 2,500. Is there a way to convert these 4,000 crossovers to 2,000 or 2,500?

Hello all,
I have to sell a new never used Maxon 110191 motor (famous on the Teres turntable. Never used (its sitting in a box since a project that never came). Selling for 50€ (because it has a broken connector, half of the normal, but perfectly usable and solderable)

To sell also 2 brand new “Mark Kelly” controller boards by Sylvain Bergeron, 25€ each.

To sell one full set of the all BOM of components for building one controller, includes the Talema transformer, just had a battery and a box, and you’re done., asking 125€.

15€ courier for the full package.
Paypal accepted, let me know and I’ll send you an payment request.
Thanks for looking.

Hello.
As you can see, this not my first post, but i have got questions, and i don`t know where to place it here.
So, i planning to build DIY Infinity Baffle loudspeakers, maximum a bigger for me modest appartaments, size of surface for each around 2m2, approximate 22 ft2. This very high sensitive - 97 db, not less.
On this moment i have one amplifier, tube, 4 watt class A on output 6P14P pentodes. I complete a satisfaction this amp, but i finding best.
So, my question is next: what amplifiers do i need to look at, or what features, or parameters, so that the amplifier perfectly conveys dynamic and macrodynamic sounds, such as explosions and shots.
I look forward to DIY kits sure, but possible of all variants.

Thank you, and be careful!

What could be lurking in those old electrolytic caps.......

There are a thousand ways to skin a cat and indecision is stopping me from making some subs.

Currently running full range drivers so looking for some stereo subs to handle low end, but can be crossed higher. Probably run Hypex Fusions for DSP/amps. Uk availability if possible.

Can anyone recommend (regardless of cab design, and can include any style but please include if they require certain design restrictions) the best subwoofers for for the below budget;

£50
£100
£200

I was wondering if it would be possible to reduce troublesome room modes with a simple box containing a passive radiator? The idea would be that the PR would be tuned to the room mode, and would resonate at that specific frequency in the location that it is placed.

Would it be best ported or sealed? Would it even be feasible? Seems like a low-cost alternative to a membrane resonator for low-frequency applications (and it would take up a *lot* less space than traditional absorption).

Finally, someone has made a Single Ended Triode Class A amplifier with deep, powerful, extended bass and highs that extend to the limits of human hearing. Together with the traditional smooth and detailed SET midrange, this is the best sounding amplifier we have heard to date.

Here is a new Lansing Audio Brand 6C33Cls-8 integrated stereo amplifier. These are excellent sounding amplifiers with huge transformers.
This amp puts out some amazing sound and has more than enough power at 15 watts per side. It uses 2 tube 6C33C, 2 tube EL34 Driver and 1 tube 12AT7 pre. Quite heavy at over 105lbs.

Taking the advantage of technical knowledge and expertise accumulated to date researching for over 20 years being attracted and absorbed in premium analog audio systems, LANSING AUDIO has been producing the highest quality vacuum tube sound systems. LANSING AUDIO produces all the individual sound product custom built with hard wiring process by his own hands using only the premium class components in order to assure reserving the original high fidelity sound tone for a long period time up to the level of carrying the product for several generations.

For more detail, please visit us
Lansing Audio: lansing audio – Professional Sound System
Amplifier 6c33cls-8 :Lansing Audio Stereo One Tube Amplifier 6C33C High End SE Triode Class A, Driver EL34, Pre 12AT7 – lansing audio

Just wondered if anyone has made a 6SJ7/6SN7 Aikido line stage yet. Remembering back to around 2003 John had designed a 6Au6/5687 line stage.
I made one and it sounded great. Yes, some would say too much gain but to repeat it just sounded so good.

This morning sitting here going thru threads I wondered if it was possible to make something a little different. I looked thru the info that was published years back and it listed different tubes and the respective parts and voltages. Not too much if memory is correct has been on the net about single front ends other than the 6Au6 that I can remember.

I was wondering if someone would join in the designing process and help me come up with something.

Hello everyone


I've been given an old iPod bedside speaker (remember those?) and since it was not wireless, and I don't have an iPod, I pullet it apart. I would discuss about the electronics in it, but that's a post for another forum, so keep an eye out on that. What I am here for is for some general advice. The thing is, I ran these speaker drivers, which I have yet to mention are the Swan/HiVi C3N. They look fairly well, paper cone and rubber surround with a shielded magnet. I pulled up a spec sheet I found online for them and ran the parameters through a calculation software, in this case WinISD. For some reason, I tried 3 different enclosure types, for instance, I used sealed, ported, and passive radiator. The only problem is that for no matter what I do, I cannot get the -3 below 120hz. I listened to them in the old enclosure which was ported, and the highs werent "sparkly" but that's to be expected because they roll off at about 15k and there were no tweeters. I say the bass was pretty decent, perhaps around the 80db range at -3db. I have used WinISD many times in the past for various projects so I can admit it is not user error. I am thinking of using a passive radiator design, as well as some simple crossovers with maybe one or two tweeters. The usable volume of the enclosure I am going to make is around 0.1 cubic feet, which is the USABLE space. The enclosure is bigger, but since it is portable things such as batteries and electronics take up some space. I was planning on using passive radiator(s) as they are notorious for small enclosure where a conventional port is not viable. Take for example the Bose soundlink mini. I like it, other may not, but for what it is, and all the tech they jammed into it, it's a great background music speaker. I have a friend who has one and we measure an approximate bass response of about mid 70's at minus 3 decibels, which is fine for what I'm doing, though lower is of course better. Not to mention my design is much bigger at 0.1 cubic feet vs 0.5 liters for the soundlink mini. Any suggestions? Thanks guys.



Also, I can list the parameters if anyone is interested, or cannot find them.

Hi,

the lytics caps // to the woofer in a passive filter are :

often lytics
always x00 uF capacitance
looks like more and more a mini-zobel as the ESR of the NPEs is increasing with years.

Should we bypass the lytics caps // to the woofer with film caps ?

I always seen 100 nF film // to 200 uF npe in commercial speakers for instance. Is it a real good idea to see such ESR mismatch for current flowing towards ground ? I mean the curent always flows toward the most easy path, aka less resistive... so is there a problem here like oscillation because of the ESR and capacitance mismatch with the // caps // to the voice coil Z of the bass - or mid- driver ?

Any rule like : bypass with 1% capacitance film a npe lytic the filter npe caps being between the plus and minus ?

Many thanks, not sure I can modelize that with Xsim like softs, would know more from members experience what happening at ears when designers choose it or used to. 😕

Hi at all.
Do you know what are the best carachteristics of the tubes, for use an interestage transformer.
Is a D3a tube a good option ?

Hi all

I'm happy to be here and hauling from corona stricken Denmark.
Have build speakers before, but that is so long ago, and back then it was a more simple time.

During this time away from work, I have been thinking about a project that has been on my mind for years.

Having a female who is the boss at home, have sent several nice big speakers out of the living room. I'm lucky to have a Libratone Lounge in my living room... How am I going to rock to such a small thing? 😛

Anyways - the plans I have had for more than 10 years is this:
Sound furniture.

It seems so simple and yet it is giving me a gigantic headache!
I should have kept my huge amplifier and my gigantic speakers!

I'm looking for parts: How to get HDMI ARC in to the system, Adding airplay 2 and ofc, how get this proposed 2.1 system to accommodate both movies and music.

My parts list is nearing something that could be done, so I hope there is a few good people here, who want me to succeed 🙂

Hi
Can't get my headphones replaced in warranty during COVID lockdown so I am forced to fix the old ones.


I have a pair of old headsets that have this volume potentiometer that I would like to bypass entirely. And keep the volume full at all times.


Could anyone tell me which pins would I need to manipulate?
I have numbers the pins and shown which direction the potentiometer goes for volume increase.



Thank you

The 2 above drivers as modeled by winisd actually shows better LF extension from the smaller driver. The SB17 would go quite a but lower but needs 16 litres or so.
I have a WAF constraint and 10 litres is my maximum.

Would the SB17 subjectively give me more 'punch' , despite what the numbers say.

I remember a quote from Zaph or Troels maybe who said you cant substitute SD and would always go for a bigger driver where possible...(was referring to 5.25")

These drivers will be used as low as they can, although I can filter out the lower octaves when listening through the Denon AVR, critical listening is straight from dac into DCG3>power amp>passive speakers

Question here.. some time ago, I (believe that I) damaged an AC-powered MP3 player by connecting it to the line-in of a vintage Fisher integrated (Philharmonic IV).

What I believe happened, is that the Fisher had a 2-wire cord (with the polarity backwards..) and both a small value cap and high value resistor tied from one side of the AC line to chassis.

This had the chassis at 120AC - albeit at a fairly high impedance.. classic "death cap" issue. When I connected the MP3, that 120AC leakage was enough to fry the player. Make sense?

So I've switched to a 3-wire cord, ditched the cap & resistor. I've also checked the input caps for the AUX input to verify there is no D.C. leakage present.

Is there anything else I need to do before I connect a DAC / MP3, etc. so nothing is damaged? I think the bases are covered, but just want to be absolutely sure.

Thanks!

I've recently acquired pioneer SA-770. Not much to look at but the first time I tried it I was impressed with the sound, reminds me of Class A which is what I like. The amp also runs quiet warm on idle like A class amps. The amp says it's non-switching circuit so I wonder if it is really Class A. Anyone knows what that means or is it just another marketing trick?

I have a Philips amplifier, but I searched on Google for nothing about this line, I don't know what model it was. The following fee information is blurred.
Everyone who can help me, thank you!

Hello hello everyone,
I am French, I do not speak English and I translate with Google translation and I apologize
help blog amplifier VTL 35 Triode.
After long years of service one of my 35 blocks dropped me HS output transformer.
I can not find the diagram of this VTL 35 Triode, I sent an email to VTL Amplifiers, Inc | Handmade In USA to ask them to help me
a photocopy of a diagram or the characteristics of the output transformer (input impedance)
they kindly replied that it was better to buy a new amplifier, commercially I find it very average ...
my VTL 35 Triode blocks. These are double push-pull, the tubes of 4. 5888 and 2. 6201 on each block.
Can you help me with information or advice?
I thank you in advance.
cordially

Capacitive load impact on distortion?

I have been working on a notch filter that can be tuned slightly to keep the notch centered on an oscillator, even when the oscillator drifts slightly or isn't accurate to begin with.

The principle has been proven, using a Bainter filter, which can be tuned with a single resistor value, without changing notch depth or Q. Basic circuit (without the tuning stuff) is attached.

The distortion however is higher than expected. From my testing it appears that it is caused by the capacitive load presented to opamps GP3 and U5. That distortion can be lowered by putting a small resistor in series with the capacitor, R16 and R17. But these resistors DO lower the notch depth so their value cannot be too high.

There is not a lot of current through those capacitors, in other words, their load is not heavy, but they do cause a phase shift between the opamp output voltage and output current I guess. Maybe that is the reason for increased distortion?

Does anyone have any experience with the impact of such capacitive load on distortion?
Does anyone know of opamps that a) are relatively insensitive to this and b) have very low distortion to begin with?

Jan

Hi all
Farnell in UK have BF256B in stock if anyone is interested.

Hi,

I'm designing a box to use with my JBL GTO 1014D (fs = 30 Hz, Qts = 0,44, VAS 30 L) and, as all small subs, I´m having a lot of trouble to tune it.

The ideal box volume is about 40L and Fb around 33 Hz. The problem is to avoid port turbulence, I need to use a 4" port, which is too long for this enclosure (about 60 cm), do it´s a quite hard to fit into the box even with curves.

Using a 3" port, the length problem is gone, but I get a ~ 60 m/s air speed peak at 31.5 Hz, 34 m/s at 40 Hz and 17 m/s at 48Hz. It's a 100% sure it will get noisy.

I was thinking about using a even lower Fb. I know it doesn't solve the problem, but the air speed peak will be located in a lower frequency were we don't have much musical information. I've simulated a Fb at 25 Hz and I got: ~ 60 m/s at 24Hz, 34 m/s at 31.5 Hz and 17 m/s at 39 Hz.

I know the port will get longer with the lower fb, but it still fitting the box and the higher air speeds still located at lower frequencies.

The other possibility is go to a sealed box. I get a 0,707 Qtc with a small 20L box. But I loose 9 db at 30 Hz and 5 db at 40 Hz. Since my bookshelf goes down to 55 Hz, I thing that the sealed subwoofer gets a little useless.

What you guys think? Where should I go without replacing the driver?

I'm trying to replace mosfets my power supply and and my output for my Rockford Fosgate Prime R1200 .1d, and I know they are irf3205 but that's as much as I know as far as how to pick them. I know the mosfet says p612d underneath the IRF3205 but can't seem to find the exact ones on digikey. if you can help me find a replacement that would be awesome. Also the output ones in need of replacing are IRFB4227 THEN underneath each individual one of those numbers is 575R, 575P, 575H. Replacement part numbers would be greatly appreciated, if anyone can help.. Thank you for your time.

I've some spare time on my hands at the moment(!) so I thought I might pick up a vintage silicon project that's been on my 'maybe' list for a long time - Aunt Corey's Homemade Buffered Passive Preamp.

Does anyone have a pair of BUF-03AJ devices that they're prepared to part with for a reasonable price?

Cheers

Hi All,
I'm new to this forum and therefore this is my first Post. I've recently finished building some rather special and rather large high fidelity loudspeakers. Each stereo side is in two parts; the top cabinet contains one GPA 16' full-range driver and will be passively driven by external amplifier, whilst the bottom cabinet contains twin SEAS 10' subwoofers and will be driven by it's own Hypex FA502 D-Class power amplifier configured in bridge mode to drive both subwoofers in mono at 1000 watts (per stereo side).
My limited experience in programming amplifiers is my problem and before the Hypex can be 'woken up' the free software download, needs to configure the amps. Easier said than done...
What with the total lock-down here in New Zealand due to the horrible CV outbreak, I can't get any external physical assistance, and it's killing me slowly just starring at these beautiful speakers with no sound... Any electronics sound guru's out there who can enlighten me will be much appreciated.

Why does making speakers feel so complicated it's like I'm trying to design a space ship or something? I'm just kinda playing it by ear and hoping I don't make any catastrophically bad design choices.

The Basic Design Constraints:
-Enclosure 3D printed on lulzbot taz 6
-One piece (No gluing multiple pieces together)
-Two Channel
-T-Glaze filament for translucent enclosure
-Small listening Room (Under 150sqft)
-Internal tapered T-Line designed to print without support
-Internal T-Line ends in the flared hole on the top of the speaker enclosure

Drivers:
-Tang Band W3-1876S 3" Mini Subwoofer
-Dayton Audio PT2C-8 Planar Tweeter

Amp:
TBD. Ideally, a DIY Class-A. Realistically, something I can buy used on Ebay.

Crossover:
TBD. Need to get further into the design.

The Status:
Basic Exterior shape and speaker placement. Starting to design the internal structure for the 3" driver. Need to work into the design to see exactly what I can do in the space available before I can even start modeling the speaker response with software.

Anything look obviously out of place so far?

I have removed the ps gets rectifiers and the drivers. Still stuck in protection. The 10uF 250v NP was blown and the power supply fets were all shorted. I can't seem to get it out of protection.
So anyone know how to bypass the protection on this amllifier?

i HAVE 5 TYPES OF 274B

PRICE PER PCS
ELROG 2745 $TBA
ACME 274B $295.00
WE 275B $265.00
274B HIFI $ 95.00
NS 275B $ 65.00

ELROG 274B

ACME 274B






WE 274B




274B HIFI





NS 274B

I came up with a Really nice looking Marantz SR 4200 receiver. after hooking it up I noticed a static noise coming from the speakers. This seems to get worse as it warms up. any educated guesses.

Looking for a pair of new or used. Shipping is to Racine, Wi 53403..Thanks

Pair Magnequest EXO 045 single ended parallel feed output transformers, 5k, 8 ohms
Asking $300
Ship Canada and USA

NOTE:

(google French English translation)

My friend who sold them to me thought they were cobalt so I made a first ad saying cobalt. have told me it was not cobalt. I canceled the announcement and made a second ad and
I assumed it was nickel because below it is marked N, but a guy said that means no DC.

So I don't know what metal they are.

Good day all,

I build this amplifier.Issue is after warp up 2 hours amp heatsink is 52degree and transformer 100++degree.i use 35vdc supply.in my mind maybe bias is high.can anobody suggest:

1.how to cek bias
2.how to add pot to tuning bias

Or correct this circuit.

Hi all,

Looking for a matched pair of either 2SK170C or LSK170C-TO-92

Must be Grade C

Let me know what you have...

Thanks

I make this d class with the help of my electronic guru mr.andrew lebon.amp is working fine but mosfet becomes hot .plz do remedy

I have made a Class d amp which supply voltage is 94-0-94 but max voltage AC i got from output is 20VAC
Can anyone tell me why this happens ???

Hello, I find it very interesting to put an inductance on the ground wire.
The first thing I have no phase and neutral if not two phases because the transformer that gives us the voltage is something old.
I have installed a stabilizer at the power input and followed by an EMI filter without metal housing.
It is assumed that the earth enters the filter and the inductor is placed in series at the output, which already goes to the terminal strip where all the devices are connected.
What would be the value of inductance, could I do it?
Cheers

I'm building my 2nd class D amp, this time in a more "official" aluminum case.

I need to start thinking on what piece goes where - where to put the SMPS, where to put the Amp board, where to put the DSP board, and then how to wire it all up.

Is there any info available like "This shouldn't be near that, never pass this cable in proximity of that specific thing/cable, never cross these types of cabling" and so on?

I'm looking for guidance to avoid making easily preventable mistakes..

I have the three pcbs from a MA KT88
(I had to swap them out with new ones I my amp because of some noise in my left channel)

Is there any way I can reuse these parts in a new build?

Would be fun to build something new from scratch.

Been playing this game for some time but I got to see the salt trick for the first time. I like his style and approach. Salt thing starts at 8:12

YouTube

Just finishing up the cabinets to the rear surrounds in the D'Appolito/Audax home theater system design and noticed that one of the two tweeters I bought new years ago (but never used) shows visual signs of possible ferrofluid leakage, but I'm just guessing; the white round label on the back of the driver is stained sort of a light oily brown over most of it's surface.

If it IS a ferrofluid leak, can it be fixed? PartsExpress and SimplySpeakers both sell ferrofluid replacement kits, but I can't ascertain as to whether or not this specific driver is serviceable.

TIA...

I have been using guitarix on my ubuntu machine for a while. The older versions of the software were very buggy, and didn't always get along with JACK.

Now, however, I am starting to be very impressed with it. It does almost everything a electric guitar/mandolin player would want. My favorite aspect of it is the excellent convolver, which has surprisingly low latency on my computer.

Does anyone else have any experience with guitarix? I think that combining it with an embedded PC and a class-d amp would make a wonderful all-in-one solution for guitar amplification.

In my opinion, it's miles ahead of anything I've tried on PC/mac, especially garageband. I've had experience with a Vox AC-30, and I will say, when I set up guitarix just right, it sounds *just* like the real thing.

A recent small subwoofer build necessitated that the ports face out opposite sides of the enclosure. The tuning dictated ports that were too long to fit any other way. I have looked and found nothing about this type of setup. Will this be ok or did I just waste a bunch of time and need to start over with different dimensions? Each chamber will have a 5.25” driver and will port out the side opposite where the chamber is.

Would you even attempt to repair this? I’m pretty busy and I’m on the fence about it myself.

David

I ended up with two of these CS4398-based DACs due to a seller issue, so one needs to find a new home.

You get a complete, tested DAC board and the correct 15-CT-15 VAC power transformer. Optionally, you can also add a 9-15 VAC transformer for separate digital & analog supplies.

The board has USB & Coax SPDIF inputs. You only need to add a power cord and optionally a case.


Asking $30.00 + ship.

First of all, a huge 'thank you' to all the great people on this forum! -You rock!
So far, I've never felt the urge to create an account because I mostly found answers to nearly all questions I had somewhere on diyaudio, but now the time has come.

Onto the reason why I finally created an account and started this thread:
A serviced pair of the awesome Infinity Renaissance 90 speakers is now in my possession (sadly standing around at the moment because my most powerful tube or SS amps with 75W are obviously not enough to get the Ren90's going plus I fear clipping the amps because the EMITs are easily damaged by that if you drive them with such an amp for too long) and need an amp capable of driving the Ren90's reliably. -I've attached the technical sheet with the crossover and an additional drawing of the bass-crossover-

The Ren90's are rated as 4ohm speakers, but, as far as I know, dip down to around 2 ohms, give or take a little.
I don't think they classify as amp-killers at all, like some Infinity speakers ~Kappa and thelike, but they are nonetheless demanding speakers, both when it comes to the quality of the audio-chain, since they are quite revealing -oh those beautiful EMIT-tweeters and EMIM-midranges, and of course when it comes to the power the amp can deliver -IMG/Infinity dual voice coil woofers were designed to be a easier load for the amp, but still need a bunch of (stable ~2ohm) power to sound their best.

I'm thinking SS mono-blocks are the obvious choice, but which? Preferably they should be diy. Maybe the Aleph Jx or the F5Tv3? (and with what rail voltage? 53-56V for around 100WClassA into 4ohm?)
Do you think they would do justice to the speakers, or should I look into commercial amps -and again which?
I should also mention at this point that my budget is not infinite. For this amp/the mono-blocks staying within my budget is however not of utmost importance, but I would like to stay under 2500EUR if possible.
That would be doable with the AJx or the F5Tv3 I guess.

Bi-amping the speakers could also be an option for me, but too take full advantage of that I would have to use an active x-over before the amps, which I have absolutely no experience with. Hence, if that is the way I should drive my Ren90's, please recommend me a good transparent active x-over.

Thanks in advance for your help and no matter, if you own Ren90's or not, please reply, if you think that you can help me in some way or have experience with similar Infinity speakers.

Best regards,
TubySS

Good day,

Item link
Replacement Amplifier Module Electro Voice EV ELX118P Power Sub Speaker w/ DSP 653753247361 | eBay

Decided to get two of these modules off ebay at 15 a piece, can anyone give me any type of information if this can work if I use it on a b&ctbx100 15 or 18 In a tham 15 or 18 box or a bass reflex box ? I know it says 500wrms at 8ohm I don't know if it does that. Really really appreciate the feedback. Again I know it's a small amount of power but I would just rather not have a bunch of processors and heavy amps to set up and move with to stick to Powered stuff plug and play.

Just for some context I already own a pair of the eV zlx-12p tops and I just want two separate subs to go with them for a small home entertainment system. Would like to get it to play generally 35hz( I know it's low idk if doable) to 100hz(idk if doable)

Ps just want something simple to build to give me a bit of low end responses.

Help anyone, with a preferred box or lf driver... Plus I can use in small open areas and maintain some OK sub range frequencies

Hey All,

While working on a 200ASC board, I managed to crack and break a small surface mount zener diode right next to the power terminal linking the 200ASC to a 200AC (see pics). Would anyone have any idea how to identify this component so I could replace it? It has no markings at all. Attempting contact with ICEPower or PartsExpress has not yet been helpful.

Thanks!

I have just restored a pair of Technics SB-F3 speakers. I replaced the 3 capacitors in each speakers crossover board. The original capacitors did not have any polarity markings on them, the new capacitors are polarity specific. There is no markings on the board to stipulate polarity. I have been unable to find a diagram for the crossover boards so have no way of knowing which of the solder points is + or -

Speakers are working and crossover appears to be doing the job. Issue is I have also changed the foam surrounds in the drivers. I understand it takes some time for the speakers to achieve maximum sound quality after changing driver surrounds so I'm not sure if I'm hearing this or the capcitors. They sound pretty good and the refoam went well but they are slightly 'muddy' sounding which is to be expected. I am leaving them on I order to allow the new foam to loosen up as advised but just wanted to check about the capacitors polarity just to be sure.

Thanks!

Dear All,

I am building a simple HV power supply to test various amp circuits. It will be used with a variac to variate the output voltage.
My question is: if I use a tube rectifier like the 5ar4, how sensitive is this tube to the supply voltage of the filament?
If I source the filament voltage from the same transformer connected to the variac, changing the supply voltage will also change the filament supply. I have I second transformer I could use to keep the 5V supply voltage constant.

Regards,

Davide

$500 or best offer
Local pick up only, NH, USA
I'm not sure I want to ship.

Any advices for up to date references ?

thanks

Single Rail TPS7A4700 Ultra Low Noise
Power Supply - 3.3V

Good for dacs or clocks...

20€ including post in Europe.

I have 4 OpenDRC's for sale, all purchased by me from minidsp.
All 4 are in excellent condition, all have original boxes.

My reason for selling is that i have recently switched to a processor/system called Q-Sys, for FIR processing.

The OpenDRC's are all currently set up as DRC-DI's; digital in and digital out.


* Unit #1 was purchased as a DRC-DA8 and converted to a DI.
So it comes with both the original MINIDAC8 and DIGI-FP I/O cards and all rear connection plates. It's pretty easy to go back and forth between setups.
I will set it up to the original DA8 if requested. $270 shipped conus. SOLD

* Units #2, 3, & 4 are DRC-DI's. I originally purchased two of the units with DA-FPs (digital in and analog out) and converted them to DI's.
So the first two units purchased come with a DA-FP (no longer available), and currently installed DIGI-FP cards. I'll set those up as a DA-FP if requested.
$240 shipped conus.

Thanks for looking, mark

The power supply as the picture shows, the resistors lose color code, do you have the color code of resistor values R08, R09, R10, R11 to share with me, you see the attached image

File sharing and storage made simple
File sharing and storage made simple

I am a complete noob when it comes to electronic circuit simulation, but I want to get into it. I wonder which software package / tools I should go with.

- I am a Linux user, and I am looking for software that runs natively on Linux (no Windows emulators or virtual machines)

- I don't want to start with with a badly limited toy. I prefer to walk the learning curve of a full tool once instead of starting over with new tools many times.

- Some compatibility in terms of netlists, device models, etc. with the mainstream tools would be useful.

- Interfacing with Python or Octave would be cool (for extended data processing or plotting).

- Which other features / aspects should I care about?

So far I have read about ngspice and Gnucap. I am sure there are others.

Any advice on where to go would be great!

Hi!

I happen to have some meters of 1.4mm cooper enamelled wire. I want to use a notch filter at 1kHz, and this asks for a 2.4mH. I thought about using a ferrite core (from a radio) and wind it myself. I know that this material will saturate easily at low frequencies, but I wonder if it will be ok at 1kHz.

Has anyone tried this before?

Hello,

I found some of vintage diode mark FR2 , made by Fuji Japan. I would like to use them in small preamp but I cann't find their datasheet, please help me out with FR2's datasheet.

Many thanks,

Have anyone tested SAMWHA for Audio capacitors ?
http://www.farnell.com/datasheets/28003.pdf

Farnell seems that no longer stock these. Is any other place, in Europe, where to buy such caps ?

Regards,
Tibi

Hi, I have a Arcam Alpha 5 Plus CD Player that is no longer picking up the CD. There seems to be a lot of noise coming from the pickup spindle and it appears to be just wobbly around randomly. I've had the lid off and cannot see anything broken, does anyone has any ideas?
Does anyone have a service manual they could email me please?
Thanks.

I started this thread because I would like all best knowledge, experience and practice on a matter to be gathered in one place: the most common reasons of oscillation in different types of solid state audio amplifiers, as well as the best ways to defeat it.

All are welcomed to share their succesfull experience of oscillation solutions.

Technicaly advanced members are highly expected to participate.

As for the current oscillation problem I'm interested in is a following CFP audio amplifier project.

Current layout without silkscreen errors:
SSA.JPG - Google Drive

Current Schematic:
SSA-HP-BAL.jpg - Google Drive

Hi guys,

i have decided to sell my amplifiers as it is currently only standing around and not being played.

I build it with better quality parts for the caps an the resistors. Here are the parts i used:

C1: 3300 uF, 50V; Nichicon KG series "Gold Tune"
C2: 1000 uF, 16V; Nichicon
C4/C4: 10 uF, 50V; Nichicon
Dale CMF55 Resistors
50k Alps Poti

It's not the original case. I used another one with the option for a poti.
In the back there is also a 230V plug, but it is not used.
I sell it with the 24V(5A) power supply from MeanWell, which is also a part of the original ACA-Kit

If you have any questions just ask 🙂

Price 280€ + shipping (i live in germany)


Regards
Nico

Hi folk's

The phonostage on my Kenwood amp has a dc offset adjust pot to apparently zero it out. It does adjust but then is unstable rising and falling rapidly.

Is there anything that can easily done to improve this so the offset is effectively kept low?

For a very simple portable bluetooth mono speaker / amp project, any opinions on which board performs with better with a 12 volt power supply (I'm looking at a very simple setup with either a sanwu TDA8932 or TPA3118 mono pbtl board as options)? I've read enough of the respective monster threads to leave me on the fence.

Thanks

Is it practical to use a subwoofer instead of a woofer in a 3 way system?

I ask because i notice that a lot of subs can be used up to at least 600 - 800 Hz, which could easily be crossed over to a midrange or mid/woofer driver, with the advantage of having extended bass response.

Everyone- The crossovers in the Dayton Audio BR1 speakers used a 46uF capacitor value. In the kit, for this capacitor they give you a 47uF electrolytic capacitor then a .1 or .01uf film to bypass the electrolytic.

So here is the question-

Leave it alone OR

I purchased 2x Erse Audio 47uF caps to replace the electrolytic. Thoughts or opinions on replacing the electrolytic? The film caps I purchased are huge lol. I will need to do something to mount this large cap

Thx in advance

Hello excuse the question, this is a class AB amplifier? What do you think of its quality?

Good morning. I've been looking for a new kit after my 1980 Electronics Today International (Australia) ETI4000s became irreparable. They lasted 40 years, with only a minor problem or two.

So I thought I'd post the original ETI kit article, just for historical value (if any).

I am looking at the Adelaide Speakers Summoner 1093DQTL kit. Summoner Series - Large 3-way floorstanders

Thoughts?

The recent audition of a Forte Model 4 in my system was sort of a revelation to me, and a step in the learning curve of how amplifiers and speakers work together. Thirteen years ago I built my first diy amp, a Zen V1 assembled on perf board. Next came the FirstWatt F5, and other iterations of the FW amps followed. I’m not a speaker builder, so the first speakers I had were a pair of B&W DM305, next a set of Focal 826W, and finally a set of Focal 1028BE. The core of my system has always been the FirstWatt amps at ~25 watts output. Now that I’m using the Model 4 with 50 watts available it’s apparent to me that my conventional speakers need more “muscle” for lack of a better term. I don’t understand that because for the most part the speakers are only using a fraction of that power most of the time. The Model 4 is a very nice sounding amplifier and seems to take control of my speakers. The mid’s and hi’s are not as smooth and sweet with the Model 4 compared to the FW amps, but the mid and lower bass sound much deeper and stronger. So now what? I’m contemplating the construction of an F5T. So is a 50 watt stereo enough or are 100 watt mono-blocks going to be better? It certainly has been a fun and gratifying journey to this point with much more learning/building to come.

Great forum find-
Spent most of my electronics life in digital and solid state design and build. Got a wild hair and bought a kit tube amp to do something different- not having dabbled in the art since the 5 tube superhet AM radio I built as kid.
Decided to go PP, class AB- So the attached is what arrived-
All works well- except the feedback loop arrowed causes about 1khz squeal after 3-4 seconds. Researched on this forum, tried changing primary and secondary windings to no avail... Admit didn't try all combinations.
So main Q is-
Amp is stable and works fine with feedback loop disconnected.... but I've read some here that a working loop will accentuate bass response of PP design. This conclusion correct? Is it worth fixing?
Thanks in advance,
Jim
ps. changed out the 75R in Pi filter to 1mh choke- if that matters

I’ve had these lying around for a while. One is in great shape. One has a small wrinkle by the phase plug. I think I received it that way. No idea if you can hear it or not. In any case, by one get one free!

$50 Plus shipping for both OBO.

Is it possible to design a power supply for a tube amplifier that will only filter frequencies 5khz and up? Would it necessarily require the same filtration as a full range amp?

In other words, since the filtration of a full range amp has to filter out 60hz, 120hz and its fundamentals, and if the high frequency amp only has 50khz and up passing though it, would it need a "standard" p/s?

I will admit I also posted this over in another forum that is not really read any longer. I thought someone here might appreciate it as I do use the PASS buffer in it. Not sure it if goes in the SS or TUBE, as it uses both kinds. Ah well.



So a long time ago I purchased an ARC SP 6 chassis (empty other than the front panel PCB) with the idea that I would put a tube preamp in it. After realizing that I had a few tube preamps, I decided I always wanted to check out tube buffers against other buffers...

So, in this one ARC SP 6 chassis, I have the following preamps:


Pass Labs Jfet buffer kit
Boozhound labs phono preamp
Boozhound labs Jfet buffer
John Broskie (Tube Cad Journal) low voltage Tube Buffer with 12AU7s.

I have hooked it up so the user can switch between the three buffers with a front panel switch. The mode selector on the ARC was busted, so it was not used. The input selector has an issue that cropped up after build, but I ordered another one and for now I am using the direct input, which I wired up like the original ARC to bypass the input selector and mode switch. The volume pot is a simple Noble Blue Velvet job, nothing great.

It is very eye-opening to be able to switch between preamps. I thought at first the Pass and Booz should sound very similar. I used the same resistors and same capacitors (Vishay Dale RN and Mundorf Mcaps) for the Pass and Booz. On the Tube Cad I used the "recommended" caps which are CDE. On the power supply caps, all of them are Nichicon Muse or greater. All wire is super great 9-9s Canare or better cable. Output jacks are the same that ARC purchases which I purchased from Michael Percy audio.

The power supply is of my own design, regulated, with just a bit more filtering than Pass calls for. Although I design preamps and amps, I decided I really wanted to check out someone else's work side by side.

So, what does this sound like?

It surely blows away the NAD preamp that I resorted to after my Mark Levinson computer controlled stuff blew up and would cost a fortune to replace. I went and grabbed some ancient NAD preamp I had (first gen preamp, I think a 1020) and I have been using that for a few years now... so it is hard for me to compare this ARC-THING to high-fi. However, I would note the following, at least.

It is certainly much more wide open, deep and spacious than the NAD. I mean, looking at the cost and parts count for any one of the three, including the phono, it would surpass anything you could get on the market near that kind of price range. Pick the Boozhound, AND get all of them from boozhoundlabs. What is that, like $340 for phono, buffer and power supply with parts? Lets add a pot and switch for $60 from TubeCad, add $100 for a chassis/feet/connectors. $500. I did not do that, as I had most resistors and caps, but the average audiohead could do it for that price. I do not think you could get a preamp to match it for that price.

Interesting notes, at least to me on my system:

The TubeCad is forward. The soundstage is in front of the speakers. Bass is deeper, or more pronounced for sure, than the other two. It seems sweeter, like someone was using a generic SS and then you plugged in your old Dynaco and went "huh, get a load of this... hrm, now that I think about it, I could listen to this all day" That is what it feels like when I switch to TubeCad from the others. The tubes are RCA cleartop 12AU7s.

The pass was the most surprising to me. I have heard one bagillion dollar pass and I was blown away. This pass seems to put the soundstage behind the speakers. It is just as wide, but the bass seems anaemic. For some reason, the TubeCad can drive the amp with authority... the Pass seems to not have enough current, or something. It is very strange.

I though the Booz would be super close to the pass. Honestly, they are nearly the same design and the same circuit. Heck, they used the same matched jfets. The pass seems more accurate. The booz seems more listenable. Both of them put the soundstage behind the speakers. The booz seems to articulate the high end more than the pass. For some reason, when I switch to the pass, I feel like it is subdued, compared to the Booz or TubeCad. Switching to the TubeCad is a big "whoa". I have owned plenty of tube amps and preamps, but to be able to go "click", oh, here is a tube pre vs a solid state. Wow.... even though it is more forward, it seems deeper, more lush, certainly more bass.

When I get my new selector switch in, I will let it burn in more and listen again. Those are my preliminary notes, from a long time lurker.

The other parts of my system for this test was a Rotel amplifier and Snell Type E/III speakers. I also used some custom Focal driver bookshelf speakers to test. All cables are custom using Canare or Kimber cable and high end connectors from the usual sources. Input signals were from FLAC audio sources on my computer, through a custom DAC driving Kimber cable to the preamp.

Random notes:

On the pass I have off boarded the input selector and potentiometer.

On the entire preamp, grounds are isolated from power ground, and only connect together at one point.

It is dead silent, even when cranked, with no input applied.



I have attached two images, one is just the preamp boards on a plate. The other is of the boards stuffed into one chassis, the ARC SP6.

Not having any success with a mtm build.
1. The woofers (6.5" flutes - 8ohm) do not go very high and what is up there is pitchy. Although, this time I realized the flutes do have robust bass if they are rolled off quickly.
2. Next tried to move the SB response lower, that was an issue and no matter what I tired they were no near the manufacturer's test results.

I assumed the mtm configuration is off the table, i,e, not enough face/baffle around the tweeter and decided with not much to lose here removed the mtm baffles and will try a tmm layout with the same drivers.

Started to think about a layout on new baffles, and almost started the cutouts but stopped and questioned: is an arbitrary layout going to have the same results.
A more direct question should I maximize the area around the tweeter?