I made these models partly to test out some changes I've made in how I go about creating models.

Note that the 3264/1295 are the same chip as the 3263/1294, just in a different package. The MT-200 versions are typically unobtanium.


.model 2SC3263-Y_kq npn ; Revision 4 by keantoken - Feb 27 2019
+ Bf=84 Vaf=150 Is=1.8p Cjc=600p Cje=15n Tf=2.2n
+ Rb=.22 Rbm=0 Irb=200m Re=38m
+ Rc=1m Rco=750m Vo=1000 Gamma=24n Qco=100p quasimod=1
+ Br=8 Ise=16p Ikf=1000 Nk=0.2
+ Itf=10 Xtf=100 Vtf=0.8 Xtb=1.4
+ Vceo=230 Icrating=15A mfg=Sanken
.model 2SA1294-Y_kq pnp ; Revision 3 by keantoken - Feb 27 2019
+ Bf=90 Vaf=150 Is=60f Cjc=1.2n Cje=20n Tf=3.9n
+ Rb=1.4 Rbm=0 Irb=3 Re=33m
+ Rc=8m Rco=380m Vo=1000 Gamma=160p Qco=100p quasimod=1
+ Br=8 Ise=0 Ikf=22 Nk=0.5
+ Itf=10 Xtf=100 Vtf=0.8 Xtb=1.7
+ Vceo=230 Icrating=15A mfg=Sanken
.model 2SC3264-Y_kq npn ; Revision 4 by keantoken - Feb 27 2019
+ Bf=84 Vaf=150 Is=1.8p Cjc=600p Cje=15n Tf=2.2n
+ Rb=.22 Rbm=0 Irb=200m Re=38m
+ Rc=1m Rco=750m Vo=1000 Gamma=24n Qco=100p quasimod=1
+ Br=8 Ise=16p Ikf=1000 Nk=0.2
+ Itf=10 Xtf=100 Vtf=0.8 Xtb=1.4
+ Vceo=230 Icrating=17A mfg=Sanken
.model 2SA1295-Y_kq pnp ; Revision 3 by keantoken - Feb 27 2019
+ Bf=90 Vaf=150 Is=60f Cjc=1.2n Cje=20n Tf=3.9n
+ Rb=1.4 Rbm=0 Irb=3 Re=33m
+ Rc=8m Rco=380m Vo=1000 Gamma=160p Qco=100p quasimod=1
+ Br=8 Ise=0 Ikf=22 Nk=0.5
+ Itf=10 Xtf=100 Vtf=0.8 Xtb=1.7
+ Vceo=230 Icrating=17A mfg=Sanken

These models were fitted mainly to the Ic vs Vce chart, which includes quasi-saturation and gives better overall accuracy even though the fit to the Hfe vs Ic chart may not look excellent. The fact is a model that fits the Hfe chart perfectly is actually likely to be a poor model overall.


Apparent deficiencies of these models:
Hfe is too high in high-current deep saturation, as the Vo parameter seems to be doing the opposite of what it should. Hence Vo has been made too high to interfere.
Vaf (Early voltage) is not accurate. It is a best guess as there is no data.
It's been suggested that Rb/Re/Rc are incorrect even though I got the best fit to the data with the current combinations.
Qco determines the slowdown due to quasi-saturation, but I don't know the best way to determine this parameter. So I've set it to a low value, which will in theory be better than not at all.


I can improve the model if someone can take measurements:

Cbe and Cbc values, and perhaps at multiple bias levels.
Vaf measurements as the current values are are only educated guesses.

Hi
I am looking a schematich for my next project about a single ended 6C33CB amplifier.What do you think about a 6BM8 (ECL82) for the driver stage ?? or this is a bad idea
thanks

Hi,
Does anyone know if Glassworks audio design are still trading?
I’ve emailed several times over 5he past few months but had no reply whatsoever
Martin

Hopefully someone can help. I recently built the 8600s with lundahl transformers. And it sounds fantastic. However, in my right channel the voltage starts out spot-on but then starts to vary. For example:

after 30 minutes.
TP3 101.1
TP4 109 one time then 29. Very strange
TP20 113
TP24 113
TP28 16

I quadruple checked the component placement and it lines up.

In addition, had an issue with one of the PCs 201 or 202 that the instructions indicated to put it one way and pages 22, the pcb chart, said another way - I put it the way on page 22 but maybe that isn't correct.

I checked the soldering but will check my solder on tube v1 pin 1, and PC202, and v4 tube pin 2?

Any advice would be appreciated.

Hello, honorable forum group. This is my first post, so I bow my head to you. As usual, I registered here to look for help in the problem that touched me and it is so difficult to solve that I need help of kind people and good audio professionals. So to the point - I'm happy owner of the Parasound PLD 1100 preamplifier, which unfortunately has failed. The problem started a few months ago with minor ailments in the form of quieter operation of one channel after warming up of the unit. The equipment went to the local service for inspection but this did not say anything. Just after receiving the PRE from the "review" for a few days it was OK. Then, unexpectedly, the equipment stopped working - first I checked the fuse above the power socket on the rear panel and it turned out that it was burnt. After putting on a new one and connecting it to the mains it was OK again, but only for 1 day because after returning from work next day I felt an unpleasant burning smell and immediately thought that something was wrong. Of course, my intuitions turned out to be right - unfortunately the transformer burned in the PLD 1100 :-(. I really want to save this unit, but I don't want to incur the cost of buying a new ori transformer because its cost with the replacement service exceeds the value of the equipment itself on the secondary market. My electronics engineer suggested that he will repair this transormator or select another one from the local market in Poland, but he must know the voltage parameters on the secondary side of the transformer in order to match the replacement that would be made by one of the local companies specializing in such services. Unfortunately, there is no information in the manual or service diagrams that I need to save the equipment so that it can continue to serve me and enjoy my ears. If someone has such a unit and can take measurements, I will be very grateful for Your help. With it I will be able to save this noble preamplifier. Please let me know if anyone is able to help with this problem.

Last year I built the simple Alpair 12.2p Small Reflex designed by Scott and absolutely love the sound, especially the detail. I'm currently running these near-field as a computer setup powered by a headphone amp, 0.5W max and it's just beautiful!

I'd like to expand on this and build something a bit different for my listening room and was thinking of another design by Scott, the Cape-Buffalo-Twin with two CHR120s per enclosure. I'd probably pair these with an Amp Camp which I already have.

I also considered the Seas A26, but in my very limited knowledge I *think* i'd prefer Scott's Twin Alpair. I don't have any firm requirements, a touch more low end over the 12.2p perhaps, listening volumes will be in the relaxed level.

Does this sound like a reasonable progression? I've attached the Buffalo Twin datasheet for reference.

BR

For Sale:

2x Mundorf CFC14 air coil /4.7mH/0,62ohm : 90€/pair
2x Mundorf CFC14 air coil/2.0mH/0,39ohm / 50€/pair

125€ for all coils

Items are located in Belgium

I am looking to test out drivers in the 5.25"-7" size class that use an inverted surround. The only drivers I am aware of are the Audax HM130C0/HM170C0.

Can anyone suggest others?

The next best thing would be a flat surround. For example there is the 6.5" Audax PR170M0 and the recent SB Audience Nero-6MRN150D 6" Midrange. Anything else like these out there?

Good evening all~ I just came into this cute little amp, & after much searching online for possible & necessary alterations to make this a guitar growler, but could come up w/only this schematic,
Having my tech just do his thing & not take it further than simply functioning well, is like bringing a Harley to a lawn mower repair guy. Is it possible for some of you kind folks to chime in with 'must do' value alterations to make this 2xEL84, EZ81, 6EU7 into a little monster.... Would immediately having him wire it for a 12ax7 or the gainy & popular Vox EF86 preamp tube be a good start? Then, what more could be swapped out for different values to make it into a guitar or harp that screams, & something more suitable for RnR than playing my dad's olde '78's through. I realize it might sound like a heap of work for ya'll, but I only know basic electronic & can follow a schematic, but have never done it myself,,, I simply want to hand it over to my tech, as I'm just an end user.
Enclosed is a chassis shot & an original schematic for you generous consideration...
Thnx in advance~

Hello,
i've made several tube amps, with a clean and a dirty channel, and when in high gain, there is a TAC TAC noise, it's dry and trebble sensitive, a TAC every 1.5 / 2 secondes. I used different diodes for the bridge, 1N4007 or faster diodes (UF something).
It gets louder with the gain and trebble...
ANy idea to understand, and maybe solve it?
Many thanks

Hi

I could use some help from Carver experts.

I own a Carver M500 power amp and a Carver M500T power amp. The M500 is working and I have just repaired the M500T. Both are 120volt models. The working one I use with a 1000VA step down transformer that weighs 10kg.

I tried starting up the M500T that I had repaired on a variac for safety. It is a Claude Lyons high quality variac that weight 8kg and is 1200va.

The M500T emitted squealing noises as I increased the variac voltage over 60 volts. I tried a few times; always with the same result. I then tried the working M500 power amp. To my surprise I got squealing noises form that also. ( However this power amp is definalely working OK when used with a a step down transformer ).

Does this mean that I can not use a variac to test start a carver power amp.

NOTE; Yes these are magnetic field carver power amps. Possibly the triac does not like the varying voltage of the variac - any comments anyone?

Thanks in advance for any help or advise

Don

Hello Mr. Nelson Pass.

I have been watching a few of your interviews and looking at your amplifier designs. Really liked your videos and views.

As you know, however, I have been experimenting with a simple class A amplifier - solder-less, all with wires and block connectors.

I do no think that I could ever build the PCBs and perform the soldering required for your kits in their present form.

Would you ever consider designing a solder-less amplifier design and offering it as a plan or a kit? That would make life easier to many people. You may, however have some concerns about sound quality and reliability.

Surprisingly, there are some enthusiasts out there who use crimped connectors and terminal blocks for their amplifier builds.

This builder has used solder-less connections extensively in his amplifier build.

https://www.diyaudio.com/forums/construction-tips/373042-tips-building-simple-alu-2.html#post6757520

There is a thread that looks at this concept here:

https://www.diyaudio.com/forums/tubes-valves/305115-solder-less-amplifier.html

I think I could manage to put together the Zen design linked above if it was solder-less but I would like to have a 18V DC input, have it run off a laptop power supply, and be content with 1 Watt output. I think your amp camp amplifier uses 19V.

So, what do you think?

Member Binary Mike passed away earlier this year, after a long battle with cancer.


Mike got his start in electronics as a child. He scrapped old TVs and radios for parts to build and experiment with. As a teenager, Mike already knew how to design with vacuum tubes. He dropped out of his EE program in college because it wasn't challenging and moved too slowly.



Mike and his wife operated an AV repair business for many years and eventually transitioned to design of industrial video equipment. They operated this business until they learned of Mike's illness.



Binary Mike had always wanted to design tube amplifiers in his retirement. We are happy that he was able to spend several years engaged in this pursuit before he passed.


Those who really knew Mike knew him as an old soul; kind, patient, and wise beyond his years. By the time of his death, Mike's mastery of the art of electronics was so complete that it wasn't enough to simply design world class tube amplifiers. He had to spice up the task with extra challenges, like getting high-end sound quality from commodity components. He wanted to reduce the financial barrier to entry into audiophilia. His designs reflect both his expertise and altruistic tendency.


Rest in peace, Mike. We are poorer without you.

Hello, can anyone recommend an engineer to service a Pioneer A400 amplifier in Surrey, UK? The amp drops the left channel at low volumes like when I listen to TV at night, the volume dial crackles. Also, one or two of the input channels don't work as well as the others with intermittent crackling/static noticeable and drop in volume level. Many thanks. James

Since 16 ohm loads demand less power than 8 or 4, it seems like any amp that could do 8 ohms could deliver at least as much power into 16. Are there any other factors I’m not aware of that would affect this?

As a related question: If a speaker varies between 4 and 16 ohms over the frequency spectrum, would wny amp that can deliver sufficient power at 4 ohm be appropriate? What if it’s a tube amp? Would it need to have an autoformer output?

(posted here because i could not find a forum for Bluetooth)

We're trying to get i2s output from the QCC3008. We can see analog output, but we don't show any i2s output.

We used the ADK Config tool to apply the following:

Configuration Set:
- Audio:
- I2S:
- BPS: 16
- Resample rate: 48 kHz
- Voice: 48 kHz
- Bit-clock scaling: 32
- Output > Channel Allocation:
- Main Group Primary Left and Right: Hardware Endpoint Type: I2S

We tried to pull pin 29 SPI-PCM# low with a 1 kOhm and a 10 kOhm R, but neither worked. We noticed the pin is still high: we measure about 1.5V on that pin with a 1kOhm pull down to ground.

We're using an off-the-shelf QCC3008 module.

Greetings all,

I'm finishing an amp with an LTP made of ECC88 cascodes. There's a CCS in the tail, with a 500 Ohm balance pot between the cathodes.
I was adjusting the balance with my scope and a 1 kHz sine. Right channel went fine, identical sines on the scope, top anode voltage on both sides 80V (B+ = 300V)
Left channel, same sines, nice. Top anode voltage 80V on one side, 230V on the other!?!
I blamed the tubes, swapped a few, but I still get the same result.
Cathode voltages are all in the same area.
I have NO idea what's going on, I hope someone can shed some light on this?
The amp seems to work fine, but this just seems wrong.
Thanks in advance.

occasionally had my hands on two sony 4560 faceplates with all stuff, boards, switeches etc. Dismantled from working units, used power vfets for another project. There are 2 pcs sk63 on each, in riaa section. I understand they are n-channel vfets. Is there any beautiful schematic of linestage or MC phono? Boards possibly? Search gives no result.

Greetings,
I'm very much a newbie. I just purchased a pair of Burson Audio Dual Opamps ( V6 Classics)

There are 4 opamps in total on my Burson Audio Conductor 3X Performance.
Instructions say I can swap either the 2 - LP Stage or 2 - I/V Stage. I'm not sure which would have the most audio impact.

Thanks so much in advance.

I have a Gustard A18 and had been playing with different opamp for the IV. The original lme49860 actually sounded quite good with a thick warm sound as compare to my other Topping es9038pro dac but not as detailed. So I want to see if there are better opamps. First to try was opa1656, didn't work, sound too sharp. I measure iv opamp output with a cheap dso scope (can only do min 20mv and 1uS) and saw a huge amount of noise 38mV at around 1.3mhz. Next tried ada4610, much better but still have 7.2mV at 1.2mhz.
Next is opa1612, very similar to ada4610.
Just wonder if the noise at the iv opamp has any meaning and should I play with the 180pf IV filter cap to lower the noise?

Hi there!

I have some very basic electronics knowledge, but can't work out how to fix a problem I am having.

I put together an amplifier (based off a d-class AA-AB32189). It is powered off its own 36v dc transformer, and there is a second transformer powering a pre-amp and an input selector (for Bluetooth and 2x rca - one off to a phono pre-amp). I have just sketched up a very basic map of the setup and will attach bellow.

There is also a wifi switch in-front of the two transformers that I can use my google assistant to turn the unit on and off.

I love the system, it works and sounds great. However, I get a loud pop a few seconds after turning it off. I have a work around with a switch that I can use to turn the amp off first, then shut the rest down. But this kind of ruins the point of the Wifi switch as I still have to go to the unit to turn it off!

I am looking for a solution to fix this pop. I assume it is from the other circuits (preamp and selector) turning off before the amp, so need a way to either delay these units turning off by 2-3 seconds so the amp can go off first (some kind of large capacitor?) or by instantly muting the amplifier when the power is turned off.

The amp has an input for a mute switch, so I was thinking if there was a way that this switch could be triggered by the loss of the 240v ac coming out of thew wifi switch this could work?

I have read an easy solution can be a cap on the amp which drains it so it shuts down quicker, but not sure If i can add this to a D-class amp?

Sorry if this is convoluted, but I would really appreciate some help on how to overcome this ! I have read a few thing but not found a solution that makes sense. And I dont know how I can get the loss of AC to trigger a small on of switch (I know relays can trigger 240v via 12v but can they go the other way?)

Thanks in advance!

Hello, I made 100R wire wound resistor with
0.08mm 114cm Manganin wire.
I have replaced on signal path resistor,
It's messy made and not stable.
0.08mm wire is so thin and fragile.
Actually it sounding pretty good.
Are there any advice or any experience?

Hi All,

I read somewhere that these tubes are designed for cascode use and that each triode in the envelope has slightly different parameters, particularly the max allowable Vhk.

However, I have been unable to confirm from this from any datasheets. With the possible exception of a a slight difference in some of the interelectrode capacitances, I can't find any mention of different parameters for each triode.

What, if any is the difference between the two triodes in the envelope?

If different, is it significant enough to preclude the use of the two triodes in one envelope as the input stages for a stereo amplifier?

Many thanks,

Greg

Hi,

I`m looking for a Denon Au-300lc in good order condition. Or Denon Au-320, as alternative.

Thanks,

David

I have finally finished the setup of my horn system.




Here is a measurement at listening position. Looks fine.

Hi,
I am an idiot. I am enjoying my DENON DVD2900, so I thought I would get another one. Being an idiot, a broken DVD2800 turned up, duh. It has the nice HDCD device in though. It didn't recognise disk, so I got a new laser off ebay (being an idiot) and have now fitted it.
To my surprise it works, sort of.
Put in a pristine CD and will load up and play sometimes quickly sometimes less.
Put in a less than pristine CD and sometimes it will load and play happily quickly and sometimes not atall.
Put in a playable but pretty damaged CD, chuggs and spins, doesn't play.

So it seems to be sometimes struggling to read the disk. When it does, it plays fine all the way through and skips between tracks quickly.

Powering up and opening and closing the door seem to be the things that affect the how well it recognises / reads the disk.
The service manual is not very forthcoming,has a few pictures of what happy disk loading ought to look like but no corrective measures, there are no tweaky pots, just mechanical adjustments, and all the test points are under the transport. So I haven't successfully looked at them on the scope yet.
The power rails look ok enough 5v rails vary between 4.5 and 4.9.

I am tempted to try replacing a few strategic PSU caps (I am a professional (idiot) I won't kill myself) just incase and investigate the power rail voltages a bit further.

Any bright Ideas?

thanks

Just trying my luck to see if anyone has a used Toroidy 0250/001 power transformer for sale.

Shipping to New Zealand.

Thanks 🙂

Anybody can help.

I need schematic 6sn7-45-IT-300B

Many Thanks


Regards


Hendra

It's a bit of an apples to oranges comparison, but any thoughts/biased opinions on each of these speakers? I am very impressed with the reputations of the men responsible for each, and the actual/potential performance of each speaker. Yes, the Statement II has a track record, and the BMR Tower is new on the scene, and yes, one speaker is a major diy project and the other is a finished product.

Assuming I had the means to properly build the Statement II, and I wanted to achieve the highest quality audio along with high spl output, how do you think the two would compare when used for the purpose of 2 channel music rather than HT?

I would like to preface this inquiry with the intention of not denigrating anyone.

https://www.stereonet.com/forums/up...FD.jpeg.fcc0c78d312e9009542b48c79802f8d3.jpeg

https://www.philharmonicaudio.com/images/BMR-Tower-Rosewood-2-smaller.jpg

Amp turns on and plays audio but at a reduced level. Goes into protection when input level is raised. Amp has signs of heat and a burnt resistor on the input board. Replaced the burnt resistor but problem is obviously still present since I didn't repair the cause. Any help on where to start would be greatly appreciated

Hi There! This is my first post. Brief introduction i have a pretty basic and limited knowledge of HiFi equipment and a fairly basic understanding of electronics (always keen to learn though).

Recently went out and bought an Onyko A9010 Amp and a set of Q Acoustics 3020 only to be left underwhelmed by the speakers performance i started remember my love for older HiFi gear and headed straight to Ebay, Google and Gumtree to see what i could find, a few days later i had a pair of very nice coniditon Technics SB-X3 speakers for peanuts. Got them home and plugged them in and on the whole was fairly impressed with their sound.

Not being satisfied i got the tinkering urge and started to pull apart check the internal speaker connections, crossover, and to give them a general spruce up. I them started reading into the capacitor replacement for the crossover and that generally electrolytic caps are bad past 20 years or so. So having never modified a crossover ever i started googling furiously for the types of capacitors to be hit with a minefield of options, prices and types. The SB-X3 crossover features 4 NPE's, 4 Inductors and one Wire Wound resistor in series with the woofer cap. From my week of googling i opted for some Ansar Supersound polypropylene as its suggested they are vastly superior to any electrolytic capacitor in an audio path and they sat at a reasonable price point.

I have just soldered them on today, expecting to be greeted with an uplift in treble brightness and clarity (seems to be the main enhancement NPE vs poly), but only to hear a muddy ruined speaker.

Hours and hours of head scratching and checking soldering i cant figure it out guys. With the new capacitors in place the Mid cone and tweeter's output are effectively reduced by 50-75% over NPE's. More research and reading into ESR issues on Polys vs NPE's i then decided to add an inline wirewound resistor in series with the cap, i tried 0.1, 0.22, 0.5, 1.0 Ohm and none made a discernable difference. THe woofer output seems unacfected and the volume seems inline with normal on the Poly cap, although people seem to leave NPE's for the woofer and use Polys for the tweeter i just decided to renew them all. I have bypassed the speakers mid/tweeter attenuators and that also made no difference.

Where am i going wrong guys? I don't have the knowledge to know what to probe or how to trouble shoot futher. I want to make it work.

I Have attached some pictures of the Crossover. The link to this manual shows the crossover schematic and PCB layout. Thanks for any help you an offer!

Technics SB-X3 - Linear Phase Speaker System - HiFi Engine

TECHNICS SB-X3 - Service Manual Immediate Download

Hi I'm designing a box with 2 Dayton RS150T-8 (40W each) in parallel combined with a passive radiator. (and a tweeter but not important here 🙂)

What I'm now seeing is that at (very) low input (10v) 25W the basta simulation excursion graph show that I'm at Xmax ? Actually much earlier if I take the frequencies lower than 44 Hz into account.

Anybody willing to explain this please ? (I can reduce the box Vb but then the charterictics are way off) ps, vent / passive radiator are exact as per vendors parameters. (SB15SFCR-00)

Thx !

Hi all

I have two identical toroidal transformers. Purchased on the same day, so probably same batch.

They have 2x 115V AC primaries, and 2x 15V AC secondaries. I need to find a way to double their voltage, while keeping them in the same common supply. Each one is capable of 15VA.

I was playing around in the software, and came up with two different combinations. See the Imgur link here.

Please let me know which would be the best method to connect the primaries.

In a weak moment I bought this pcb from ebay:
1 Stück vergoldet EL34 Push Pull Röhrenverstärker tube amp DIY PCB | eBay
It has a 5751 as input tube and ECC82 as longtail splitter.
I am going to change the Ecc82 for a ECC99 or a 6CG7 and a CCS.
But is the 5751 any good for input tube for hifi?
I have seen some use 12AT7 as input tube,but I don´t know..

Hello! I need a phono preamp circuit on nuvistors - I want to make such a device for myself . Can anyone suggest such a scheme? Perhaps - someone has already made such a preamp and got a good result. I will be very grateful for the information .

A FaceBay sale and I just collected. I thought it was worth taking a chance on a 20 minute drive and a $20- sale.
One of them is a decent enough generic 10" 4R woofer but the other.
It's a Paradigm in excellent condition.
Looking now for any information on the Paradigm B156 WFP Also note some extra numbers on the sticker W02200
Cast alloy frame and a poly cone with stiffening ribs and about 15mm of travel. Dusty and needs a clean but measure 8R

I sell three different condenser microphone amplifier modules for Chinese BM-700, BM-800 or similar microphone body on eBay:

1. CM-1A (Starting lvl);
   
2. CM-2A (Middle lvl);
   
3. CM-1XP (High lvl).

Compatible capsule: 34mm condenser capsule or 25mm electret (without built-in JFET). Required 48V phantom power.

Amp powers up and then goes into protection mode .

I noticed I get 7 volts of DC measured directly across the speaker terminals when the amp powers up

All the outputs test fine .

Any ideas ?

what can I expect the sonic differences to be between the SEAS 27TBFC/G and 27TBCD/GB-DXT? I would like to make a two way with an 8 inch woofer.

Hey All

Selling one complete (but unpainted) and two 90% complete Gedlee Abbey speakers (total of 3 speakers). I found out I'll be living in Portugal a good amount of the year, and I won't have the time to finish this system. That's the ONLY reason I'm selling. These were going to be my end-game speakers.

The 90% complete ones are detailed here:

FS: Geddes Abbey incredible speakers DIY opportunity includes speaker stands

Happy to ship via something like uShip. That's how I got the 90% complete speakers and they arrived perfectly at a very reasonable price.

Looking to sell everything together for $2,000. You pick them up in Brooklyn, NY or pay for uShip to pick them up and take them to you.

Thanks for looking!!

-Jim

Pics here:

Imgur: The magic of the Internet

Hello
I would like to ask the forum if you purchased it from Jac music in Germany is reliable? and you ask that because I deposit money for a transformer from 28/03/2014 and despite repeatedly e-mail you've sent I do not have ANY INFORMATION
Thank you

Hello,


I own a Cambridge Audio 851c CD-player/DAC/Pre-amp which I am currenty using av a DAC/Pre-amp.


Lately it has started acting up: WHen powering it on it will produce loud, static white noise. Usually switching it off and on a couple of times removes this problem, and it works as expected after this. However, as this i quite annoying, I decided to open it and have a look inside as the unit is out of warranty.


I inspected the insides and found what appears to be bad capacitors on the power board, which again is connected to the toroidal transformer. The DAC/pre-section looked fine.



I've attached some pictures of the power-board.



Could this be the cause of the problem described?
Could swapping the capacitors be a simple repair?
If so, does Cambridge Audio use "standard" soldering lead, or is there something which I should be aware of?


The values of the caps that seem bad are as follows:
C3 - 15 uF 450V, labeled 1921TQ
C14 - 1500uF 16V, labeled 92GW
C2 - 1000uF 16V, 10IICH


If this might be a matter of simply swapping the caps are there any recommended brands/types of caps or will any do?


I appreciate all and any input, thank you.

The amplifier turns on, the green LED is on, it does not go into defense, but there is no sound in any channel, more precisely, if you bring the speaker to your ear, you can hear the music very quietly. Can anyone come across such a problem or have a circuit for this amplifier? If you need to take a photo, write.

Folks:

I rebuilt a chip amp this past summer (https://www.diyaudio.com/forums/chip-amps/79303-chip-amp-photo-gallery-171.html#post6695088, post #3403) which now consists of a Super Gain Clone amplifier and RJM Audio B-Board diamond buffers and it has been in service in my kitchen ever since. It does two troublesome things: about half the time it is turned on, a second or two later it turns itself off with a loud "thump". By that I mean the illuminated latching power switch actually reverts to its "off" state. The second thing is that when I turn the amp off, it invariably issues a loud thump as well.

Ghosts maybe? A cap across the power switch? Your counsel is appreciated.

Regards,
Scott

I need to socket a Novar tube PCB, but B9E sockets are rare and very pricey.

However B9D Magnoval is in production and available very cheap.

These two bases have identical circle diameters pin center to pin center of 17.45 mm.

But the pins diameters differ by about .26 mm. Novar are 1.02 and Magnoval is 1.27 mm.

I'm thinking I should be able to plug a Novar tube into a Magnoval socket, there should be enough closure in the springs to make contact no? its only .26 mm short.

As long as I never plug a Magnoval tube into it which would then stretch out the springs making the socket too loose for Novar.

For Novar tubes do fellow DIY'ers get good enough contact using the widely available B9D sockets?

Melos tirode 200+ schematics looking for

Hello
I own a Melos triode 200 plus stero and I have problemas with one output (noises and distorsions) and when the problems began the powamp produce a terrible burning smell. It seems a transistor burning smell.
I'm looking for the schematics, but "Melos audio restoration" is closed, Melos audio is closed too.
Please somebody have the schematics?
Thankyou very much in advance
Roberto

Is it really that bad using a sealed sub with ported main speakers, I notice that some manufacturers do it in their ranges i.e. Monitor Audio in the Silver range.

Hi all,

This amp was in protect. Changed outputs and the amp comes on but seeing -1.5v on output terminals without signal. When signal given it is still having same -1.6v but when I increase the gain until it clip the voltage disappears (with no load).

Hello !

Does anyone have the schematic / service manual from Ground Zero GZIA 2230 HPX?

Thanks

This schematic are most likely a earlier version of the well known mullard 3-3 amplifier using different tubes than the the later version we all know real well (EF86-EL84) . This version uses EF40 as the pretube and EL41 as power output tube.

Enjoy 🙂










Btw . There is a third version of the schematic too that uses EF36 or EF37(A) and EL33. But i have not found a schematic yet on this version.

I would like to get polar data for my speakers but a lot of my speakers are large so a turntable is quite impractical. Instead I would like to build a 90 degree microphone arc with 5 degree spacing (18 microphones) at a radius of 3m and use a multichannel interface to capture the sweep. This would look similar to the Dynaudio measurement chamber:
Dynaudio: inside the speaker corp's state-of-the-art measurement facility | Home Cinema Choice

it would be very expensive to purchase 18 commercial measurement microphones, however I have constructed a microphone in the past using these instructions:
System Test
the WM-60AY capsule is no longer available though. Is there a modern replacement? perhaps MEMS?

Hello, i can't hear anyting over 13K... 20€

In fiddling with my composite amp ive found out that two of my toroidals dont sound the same.

One is an antek 300va 24 0 24 0, the other same spec but a local korean brand. They weight about the same. The amp uses lm3886 for output and a simple C filter (not crc)

Simply put the antek sounds much better. The bass is bigger, theres better grip on the lower notes. The korean transformer sounds tinny in comparison as if the power has been halved.

I couldnt get much out of how the korean toroidal was wound except that their core is outsourced (so probably cheap chinese) and they have hum issues (primary wound close to saturation?)

What would differ in a good and bad quality toroidals and how would that affect the bass in a class ab amp?

Thank you for your input in advance.

I’m just trying to get a reference for what more experience people find useful. I’ve mostly been using .075”, but its time for me to reorder and I wanted to know if there was anything else I should try.

My question is: why are all the output sockets I see in all turntable phones all single-ended? Why are they not balanced?

I was under the impression that if

• you have a floating differential signal,
• the signal amplitude is low, thus making it vulnerable to noise pickup

you have a textbook case to want to feed the two wires to a differential input of a balanced or differential amplifier. And I was under the impression that all cartridges, like most (passive) mics, are passive transducers which will generate a differential or "balanced" output. Basically, phono cartridges and XLR connectors and balanced interconnects and XLR inputs to phono preamps seem to be a match made in heaven. This is certainly true about mics and mic preamps.

Yet, I find all turntables fitted with RCA sockets. None of them (that I've seen) are balanced. (I'm sure there are a few, but that's not my point.) Why? Is my understanding of what constitutes a balanced signal incorrect? Is there some other reason why all turntables and phono preamp inputs in the world do not do balanced connections?

I tried searching, but couldn't find anything which discusses this. Maybe my searching was inept.

If you bi-wire your speakers, is it better to remove the jumper cables, or to keep them?

I've been dabbling in alternative technologies for a while now.
Usually they involve gluing 1um thick mylar to something.

I have very rarely been able to make anything close to a perfect diaphram.

For starters getting the mylar to be taught without wrinkles and without ripping the mylar is..somewhat of a challenge.
I currently just unroll the mylar and kind of stretch it out onto a mirror and kind of hope for the best and gently push the wrinkles and bubbles out.

Then I apply super 77 to it and apply the aluminum.

However, this is crude, annoying, slow, and imperfect.

I've tried ordering rolls of metalized mylar from china but they always tell me something along the lines of "sorry this is meant for capacitors" and then shut me out completely, the moment they get a hint that I am doing something unusual which is hard to avoid because they ask for a bunch of capacitor related technical parameters that I don't need or don't understand.
I'm not sure why they just don't take my money...

In any case. How would a professional do this?
Is there some contraption I can use to accomplish this quickly and easily with perfect results every time?

Hi All,

I noticed an ad on FB marketplace that may appeal to someone. This isn't my stuff. I don't know the guy. But I have been super curious about some of these things, so maybe you are too:

JBL 4628B- $300 ea., 4 availablec
JBL 4695– $550 ea., 2 available
JBL 4699B - $650 ea., 2 available
JBL 4625B – $200 ea., 4 available
JBL 4602A - $350 Each, 4 available
JBL 4691B Cabaret Series Speakers – $300 ea., 4 available

The link is here if you have FB: Log into Facebook

I'm working hard to not buy a pair of the 4628Bs just to check them out.

Paul

Superb woofers, these were only in use for about 20 hours in a prototype design, and are in brand new condition.

$700 for the pair, will ship in the original boxes.

Cheers,

Ken
ken@songeraudio.com

with an amp purchase ? Let me know.

FS: HK Citation II Cage (Reproduction) $79

This is a brand new, high-quality, heavy-duty cage for the Harmon Kardon Citation II Amplifier.

It is professionally painted black. Attaching hardware is not included. The price of steel has tripled in the last year or so, and this unit is sold below cost.

I have a source for the hardware kits -- about $18.00. PM me if interested.

$79 + shipping

I have one channel outputting 18VDC and no idea where to start troubleshooting.
Any help greatly appreciated.

Looking for a finger lift and armrest for a Pickering 194 or 196 tonearm.

So, I've had my VFET amplifier since Thursday and it's now Sunday morning. It has cured my Audiophilia Nervosa (i.e. FOMO) but a worse complaint has set in. I have incurable insomnia! That's right, I've barely slept in days!!

I keep thinking about my music collection, most of which I haven't listened to in 15 years, and wondering how this album or that album will sound. So far I've gone through Michael Franks, Jennifer Warnes, Stanley Jordan, Bill Withers, Thomas Dolby, Ricky Lee Jones, Steely Dan, the Doobie Brothers, Ryuichi Sakamoto and all my test albums. I've started buying CDs again just to hear how they sound.

How can I make it stop?? Argh!!!!

variable DC poewr supply to drive TT motor

Hi all,

I'm looking for a stable lab varible DC power supply to drive a Maxon A-max motor driving my TT.

Found one for sale with:

Ripple & Noise: <1mV rms
Waves and noises: CV<0.5mV r.m.s, CC 3mA, r.m.s
Power effect: CV < 0.01 % +1mV, CC <0.2% + 1mA
Overload effect: CV<0.01% +3mV, CC<0.2% +3mA

could such a supply run my platter good and steady?

Thanks all
Ik

Been an interesting few weeks.
Been trying to sell on a few bits.
1/ Ebay now just a rare sale.
2/ Amazon, listings rarely shown by Amazon so no buyers.
3/ gum tree, no bites.
4/ Ebuy, no sales
5/ DIYAUDIO swap meet, next to nothing sold.

Recession here ?

So after seeing some of the threads on here, and seeing many tubes that would be useful but not finding any sockets, I've designed a PCB based socket for them.

It uses a set of nine Keystone 1434 as the socket pinholes. They are easy to desolder in the event they wear out.

The connections are made to screw terminals.

There is a centre hole to make drilling the chassis easier, too. EDIT: The hole is 3mm. I now know some Novar tubes have the evacuation tip on the bottom. The hole can be drilled out if needed.

To the mods - Move to Vendors if necessary. I post this in parts so people will see it.

Oh, and Happy Wednesday.

Koda

I can detect a 0.5% change in pitch at 1000 Hz...... for instance changing it from 1000 to 1005 Hz.
Who else can dump their comment(s) on here and make it a decent thread?

Hi all,

I am in the process of putting together the parts for my RH84 V.2 EL84SE valve amp.

RH Amplifiers: RH84 amplifier - revision 2

I will be using NOS Russian 6P14P-EV in place of the EL84s.

The suggested rectifier power supply by the designer is a 5R4



The datasheet is here
http://www.r-type.org/pdfs/5r4gy.pdf

I was wondering about using a Russian 5C3S which is being advertised as being equivalent to a 5U4G.



Russian tube 5C3S is a quality equivalent of the 5U4G. Military equipment, high reliability. Svetlana factory. OTK marking.
Name: 5C3S
Type: double-anode rectifier
Application: alternative current rectification
Cathode type: oxide, direct heating
Envelope: glass
Mass: 72g
Filament voltage: 5V
Filament current: 2,7-3,3A
Anode voltage: 75V
Anode current: 0,225A
Socket type: rsh5-1
Max.reverse anode voltage: 1,7kV

The data sheet is here
https://drtube.com/datasheets/5c3s.pdf


The reason is purely down to looks of the tube at this stage. I have tried using the PSD2 software but I am such a novice I am not sure if I have done it correctly.

I have bought Lundahl LL1663 SE OPTs


http://www.lundahl.se/wp-content/uploads/datasheets/1663.pdf

and a Toroidy 10H 250mA toroidal choke for the amp project and will be using 8ohm speakers.

TDS10/250 - Toroidal Choke 10H 250mA DC - Shop Toroidy.pl

I am thinking of using a Hammond 372DX Transformer with
600V CT@144ma, 50 VAC, 5vCT@3A, 6.3VCT@4A which is a bit overkill but would enable PSE in the future I think.

The B+ is 315V

Can anyone advise on the choice of Rectifier tube and any changes to the capacitor values that may be needed to make this work if possible run the PSUD2 software to check the values for me. If it is a no and not worth doing then please do say

If this is in the wrong section could admin move it to the right section?

Thanks for all your help.

Lee

Hi,
i feel like i need to add the 3rd drive into my 2way JBL GTO 609C front doors set. I will custom install it into the A pillar, the tweeter i would probably let them in factory triangle on the door because they would be alligned but would make a custom mold also for better aiming.
The tricky part is what driver would i choose. I don't want to spend very much on these (even tho i know they are crucial drivers regarding clarity).
To keep install ok i would need 3" drivers (4" would be too big)
I have seen real budget speakers from 10USD to 60USD (a bit much for me at the moment).
What brands from the following will i be best with:
Visaton, Lavoce, Dayton Audio, Hivi, Fountek, Monacor, Tang Band and Peerless
From specs, some are even widebands.
They will be amplified (even though i've seen these requiring 15-20 W RMS most)

thanks.

Hi everyone,


This is my first post here, so if I'm doing something wrong, I'm sorry!


I'm repairing an old organ, the previous owner tried to tune it and destroyed what was probably a trimpot (which is now totally missing).
According to the schematics, the part "number" or "name" is "23.515".

I've found pictures of the missing component: Infrequent Sound [sex.tex] technology: GEM Galanti Group Rodeo 49, made in Italy
My missing part is the bottom left potentiometer.

Does this "23.515" refer to something standard ?

Thanks for any advice!

Greetings all,

I have hesitated to which sub-forum to post the topic, but as it is relevant to a low-frequency part of a multi-way speaker, I believe that this sub-forum is the best.

Background

For one reason or another, I had to give away my fully horn-loaded system and live with headphones. I am now in a position to acquire/build a pair of speakers, though not by replicating my former system. I have been contemplating a three-way, preliminarily a MEH above a 15 inch low-frequency driver. I seem to have a preference for a sealed box; which may well be because something always bothered me in a certain frequency portion of ported box. So, I will limit the following drivel to that topology.

Problem definition/proposed standard

From my understanding, one of the criticism of sealed box, and I am paraphrasing, is a “lack of low frequency extension and low efficiency”. Admittedly, this is a rather ill-defined statement, so let me attempt to qualify it vis-à-vis my preferred music genre.

As I tend to listen mostly to classical music, I have found two topics that appear to be relevant: “What high efficiency speaker for Classical Music?”, https://www.diyaudio.com/forums/multi-way/292232-efficiency-speaker-classical-music-26.html, and “A Test. How much Voltage (power) do your speakers need?”, https://www.diyaudio.com/forums/multi-way/204857-test-voltage-power-speakers.html.

I understand that different people may have different opinions regarding the required SPL, still, given the title of at least the first topic, one would expect at least some commonality, but the amplifiers range from a 2A3 to high-power solid state, and associated differences in the amplifier’s power.

In an attempt to understand the power requirement, I propose the following. According to my understanding majority of classical pieces do not have much content below about 40 Hz. Of course, there are exceptions, e.g., P.I. Tchaikovsky - 1812 Overture; R. Strauss - Also sprach Zarathustra; some G. Mahler pieces – 8th symphony, but they are that – exception. Since I live in a quiet environment and my listening preferences are on average 80 dB or less, assuming that the dynamic range of classical music is 20-30 dB it follows that 110 dB at 40 Hz peaks should be the standard.

Method

1. Driver selection

My first naïve idea was to look for high-efficiency 15 inch drivers, but, as I quickly found, they have about the same efficiency, cf., Table 1. So this does not appear to be a silver bullet.

2. Required power vs Vb

Recalling J. A. Hofman’s “iron law”, I decided to investigate the relationship between an enclosure’s Vb and a power that would satisfy the above-proposed standard. I started with Vb=100l, not due to any sophisticated reasoning, but simply because I had built such an enclosure; the idea having been that I had to start somewhere, and by comparing a model for the specific Vb with a measurement, it may be reasonable to correlate to different volumes.

Using Unibox v. 4.08, I had adjusted the power to the required SPL at 40 Hz. I repeated the exercise for different volumes, cf., Table. 2.

Notes: (i) Table 2 summarizes the model without any consideration for a room gain;
(ii) I was not concerned about exceeding the Xmax for the frequencies below the 40 Hz as this is an implementation and not conceptual issue.

Conclusion/Discussion

1. The parameters Fb and even more F3 are not strongly dependent on the change in Vb;
2. There is an inverse relationship between the Vb and the Qts;
3. There is an inverse relationship between the Vb and the power, which agrees with the “iron Law”; and
4. There is no escaping the conclusion that, assuming that the above-defined standard is to be achieved, a power higher than presented in the links is needed.

Provided that the conclusions are correct, and please do not hesitate to point any flaws in my diatribe, the above now presents at least two questions:

1. What would be the best architecture for an amplifier that will be most of the time supplying power 30 dB below peak, considering preliminary frequency of operation 40 Hz – 350 Hz?; and
2. Disregarding WAF, is there any guidance on selecting the Vb, considering the Vb to Qts relationship?

Kindest regards,

M

Table. 1

Driver Fs [Hz] SPL /1W/1M [dB]
TAD1601A 28 97
TD-15M 34.7 97.8
JBL2226 40 97

Table. 2

Vb [l] Fb {Hz] F3 [Hz] Qts Max SPL [dB] Power [W]
101.7 56.1 60.81 0.655 116.30 155
111.9 54.15 60.81 0.632 116.30 145
122.1 52.47 60.26 0.617 116.10 140
132.3 51.01 61.38 0.601 116.00 135
142.4 49.72 60.81 0.585 116.00 130
152.6 48.57 61.94 0.576 115.60 125

Hello all,

I have a Myriad Mi Integrated Amp that has been running well until recently. It hasn't been used for about 9 months and the first time I was listening to it after that it was fine for about 20 minutes and then the amp wend dead, I heard an on-and-off 'buzzing' noise for a few seconds, and then I saw smoke. I pulled the plug and opened it up.

After some investigation it seems that a Varistor (one of two) has blown. In the attached image it is circled in red, it is labelled 'VDR2' on the PCB, the second one is circled in yellow and labelled 'VDR1'.

All other components seem okay to the naked eye.

The two Varistors seem identical. Due to the location of the blown one I can not make out all the markings at the bottom but comparing it to the markings on VDR1 they seem to be identical components (see attached photos). The text that I can clearly read states "ZOV 14D471K (various certification markings) CH52Z".

Some observations that I found interesting were that (a) the two Varistors seem to be identical yet the blown VDR1 is a paler green to the good VDR2, and (b) the failed VDR1 had some heat shrink completely covering it which burned through when it failed.

As I understand it these Varistors are a layer of protection in the circuit to protect from over voltage spikes. Is it logical to assume that this was the cause or could it have just failed independently? If it is likely to have failed due to over voltage would that be coming from the mains supply or a failure upstream in the circuit?

So I have a few questions:

1. Is the colour difference likely due to heat during or leading up to the failure or maybe a different batch, a potential cause of failure?
   
2. Why would there be heat shrink over only one of the Varistors and not the other? Could that have caused overheating and premature failure?
   
3. Can I just replace the failed Varistor with another ZOV 14D471K (of any manufacturer), turn on the Amp, and see what happens?
   
4. Finally, whilst I'm 'in there' is there any point at all replacing and upgrading any of the other components - Cap upgrades for example?

I look forward to your thoughts and advice.

I picked up two hundred 1W 270R carbon composition resistors for a $2 at a ham swap last month. The resistor body is 15mm x 5.8 mm. I was going to keep them as my "lifetime" stock of grid stoppers...

Is there any rule about not using 1 watter's as grid stoppers? They should have no difference than 1/2 watter's in that position no? They certainly have twice the carbon 🙂

I'm kind of prolific when it comes to "making waveguides", but the crazy thing is that 25% of my projects never get posted. Basically I'll make a waveguide in 2-4 hours, print it, measure it, then forget about it for one reason or another.

This is one of those; I don't think I've posted this. If I'm wrong, apologies for the double post.

For some reason both channels of my amplifier thermal protection LEDs are on and the amp does not activate. This happens as soon as I plug in the unit and the power switch in OFF position. When I power on the amp, it does work, but no sound and the transistors are not getting warm at all (both channels). Any help would be appreciated.

Greetings everyone,

I watched this CXC mod video:

[wiki= https://www.youtube.com/watch?v=VoxC3st7WQw]%[/wiki]

And following, relocated the two cables and put a book on top to deal with resonance - these changes made a noticeable difference. I intend now to apply the resonance dampening material inside and will solder in a BNC connector. Near the end of the video, Miguel suggests adding a capacitor to the output, but, no details are given. Has anyone any idea what he’s suggesting, where this cap would be installed and what value?

Any and all information appreciated.

Thanks,

John

Hello everyone !
Here is an updated build or my project :
I want to build a portable "boombox". I must insist on the "portable" as I don't have a car nor a bike. I'm tall and still in "good" shape so I think I can easily move around 15Kg (and If I can't, I'll just use a small trolley, or go to the gym 😀). Usually parties are outdoor, playing for 6hours, for 50-100 people. It won't be the only speaker, it's to support an already existing setup with several boombox (sometimes only one Aiwa Exos-9, which is not enough, that's the main reason why I want to build it). My budget is between 500€ and 750€. I live in France and the wood I can get would cost me around 50€-100€ for MDF (which I entend to use).
I'm not looking for perfection here. The project is basically a cheaper soundboks gen. 3.
Thanks a lot for the help 🙂

Here is the new build :
Mid/bass 10" drivers : Eminence Beta-10A – Thomann France x2
Tweeter compression 1" : Celestion CDX1-1010 – Thomann France
Horn. : Celestion H1-8050 – Thomann France
DSP 2x4: miniDSP Kits: miniDSP 2x4 kit
3way amp : WONDOM AA-AB35281 T-Amp Class D Amplifier Module 3x200W 3 Ohm - Audiophonics
36V battery : https://fra.grandado.com/products/3..._BwE&variant=UHJvZHVjdFZhcmlhbnQ6MjA1MDY4NDg3

Let me know what you think. 🙂

Hi All

I just wanted to share this unit gain headphone amp circuit I designed and built it on Sunday.

So far it has exemplary performance and specs considering its simplicity, the built version exceeded my expectations:
Even thought I show a cap in the circuit, if the JFET's are matched the circuit is DC coupled input to output. I built 2 channels and 1 channel has 4mV DC offset andthe other has an 3.4mV DC output offset
The frequency responce is crazy I measured the responce to be almost perfectly flat with 0dB from 10Hz to 1MHz into a 33R resistor.

The specific JFETs isn't critical as long as IDSS is greater than 3mA and they are matched. I simulated with 2sk170GR, 2sk246GR/BL but I built it with 2sk117Y's (the model of the 2SK117 wasn't good).
The output bias current it set by 0.65/R75+R76, in the built version I went with R75 and R76 5R and R50 10R so it didn't run too hot.

I put it in a box last night and listening to Leonard Cohen with it now.

Have to give credit to Nelson Pass for his constant current stage and Erno Borbely for inspiration.

Cheers

Tim