I'm planning to put a double din head unit in my older Porsche. My plan is to buy an aftermarket steering wheel and put 4 momentary switches in the aluminum webbing of the wheel, for volume up/down and radio station change. I will run these through a clock spring with sufficient terminals, which I've found for my car. I don't want any other features. I've seen a few generic head units on ebay whose description say

"Features 2: Support steering wheel control"

Does that mean there will be wires from the head unit that can be used for this?

I would rather not use a control box such as the ASCW-1.

Here is an example of one of the units ebay head unit with steering wheel control

I've had those LX5 tweeter in my drawer for 25 years I've always like the liveness they can add to the room. I've decided to use them as surround in a dipole arrangement. SB13PFC Woofer back to back sharing the same enclosure. I build the enclosure and measured the response and ended up with a 10db dip at 430hz one octave wide. It is probably mutual cancellation between the two speakers.
Before i undergo cutting the top to separate the chambers, i am looking for other solutions that would not involving woodworking.
I was thinking of running one woofer like a 2.5way, cross low and skip the BSC on the xover.
Are there solutions, any idea or past experience on similar design from you you can share to remove this dip.
Regards

You will see me post this exact thread on a couple other places, because all the forums have shifted around a bit over the last decade and a half and I want as much useful feedback from a diverse crowd as possible. I've been sitting on a single Soundsplinter RL-P15D4 for about a decade now, biding my time until I finally got all the parts for a build (I got the driver, then a calibrated umik1, a db meter, and then finally for my birthday last month I got a Behringer NX3000D) I've moved in between so what was a theater in a 20x20 room morphed to an upstairs 3 wall theater with a 7.1 setup that was 11x21 to about half that because I had to build a room for my mother to move in (so it is about 11x11 now). As I am short on space, I have to make a coffee table style subwoofer with a front/rear firing (I originally was going to do a sonosub). I've already had all the mdf cut for a box that is 11.3cf (320L) with a 8" port that according to WinISD should be 41.15 inches for a 16hz tune. This will fit in the longest size of the box since the external dimensions are 50.5Lx27W.25x20H. My options for the port are evidently sonotube or sewer pipe, the sewer pipe being some super thick stuff that evidently weighs 8lbs per foot. I do have a Creality CR-10 S5 though with which I can print my own (it has a print area of 20"x20"x20").

My main concerns is the ~8 inches headspace enough for airflow (considering I think I have to add around a half inch for the flare. I have seen an alternative to a regular port, which is the Polk power port design which I've seen a couple builds on but they were all before 3d printing was possible (people had to get them turned on a lathe, or use a router to round the disc, etc). So for the same tune, according to the calcs, the port length only has to be 13.215 inches. Assuming the power port works as intended, the nice thing is I can fairly easily adjust the tuning just by increasing the internal port length (which I can do by printing the tube as a threaded two piece pipe).

Any thoughts or should I just stick with a long tube and call it a day? I'm also looking to try and find a second driver, but these things are over a decade old and finding a somewhat unused one will be hard (have to post in the wanted section and see what happens).

Eventually I'll be moving the whole theater down into the basement, but that will be a whole other project (this used to be my grandparents home). It still has a dirt floor basement but for some reason there is a huge concrete walled area in the corner that has 1'3" foot thick walls that are about 4' high and about 12'x6'. If anyone has ideas for that, let me know! The family story is she hired a Polish guy to make a Russian oven and something got lost in translation...the unfortunate thing is that there is enough concrete from that to have put a floor in the whole basement....

Shango

Sparkler Audio S508 Phono Stage $1,100.00







Specifications (S508v/S508i)
Power Supply: Worldwide, depend on market (IEC 3 pin AC inlet), AC110~120V, AC220~240V (factory assembled)
Input Terminals: Unbalanced RCA pin jack, frame ground terminal.
Input Impedance: 0Ω - total gain is determined by cartridge internal resistance.
Gain: 60..75dB（@1kHz) - adjustable by gain switch.
Type: MC cartridge, CR network RIAA equalizing, NF de-emphasis, current amplifier.
Line Output (S508v - voltage-mode): Unbalanced RCA pin jack, 2.2Vrms
Line Output (S508i - current-mode): Unbalanced RCA pin jack, 5.5mAp-p
Operations: Power switch, Gain switch (high/low)
Size W260×H46×D160mm - B5 size, Weight 1.46g (without power cable)
Materials: Stainless steel, hairline finished. Stainless top panel with clear acrylic.
Accessories: power cable for IEC 3 pin AC inlet, userʹs manual.

Is a pure tetrode (not Beam Tetrode) optimal for audio?

In tetrode or UL Mode.
I am talking about the Western Electric 350A in particular.

It is a pure tetrode.

Hello

As i have ordered a couple of wifi/bluetooth amplifiers (Arylic Up2Stream Amp 2.0), and wanted to build my own first set of speakers for them.
I found the Dayton PS95-8 and DS135-8 to be the right size(and cheap).
So here is the idea i have come up with:
PS95-8 - full range in upper chamber.
DS135-8 as a low(ish) woofer with a DS135-PR passive radiator in the lower chamber.
The lower chamber has these internal dimensions 15cm/15cm/15cm, and the upper chamber is 15cm/15cm/10cm.
I have uploaded a quick rendering of the idea i have.

What kind of crossover(if any) would be needed? or would notch filters be enough?
Here is the curve of the 2 speakers.


Link to the drivers:
Dayton Audio - PS95-8 3-1/2" Point Source Full-Range Driver 8 Ohm
Dayton Audio - DS135-8 5" Designer Series Woofer Speaker 8 Ohm
Dayton Audio - DS135-PR 5" Designer Series Passive Radiator

Kind regards

Hi,


I'm looking for the sce manual/schematic of this little Proton integrated amplifier with Sanken transistor from the late 80s...
Anyone please ? One channel is buzing/huming and pass no sound from the source... Lock down debugging project... would like to check the power trafo voltages.


Many thanks

Hi,

I am doing a little DIY at home, apologies this isnt really audio related!

I have begun to build a cabin bed for my eldest son, which I plan to hang on the wall. The room is literally the length of a single bed, so the bed will be supported on 3 sides.

On the long edge I have a brick wall, and also at one end, and I have some sturdy looking M10 anchor screws, and something like 7 or 8 anchor points along the bed frame length., and foot end, placed every 8 or 10 inches.

So I am then left with the head end of the bed, which is hollow wall.

I'm looking for some suggestions for plasterboard fixings that I can rely on to take their share of the load.


TIA for any help

Hi all,
I have this Nad 216 THX toroidal transformer but I have no idea how this thing should be wired. It is 120V/230V.

Measurements:

Black-green 0,7ohm
Black-orange 0,7ohm
Green-Orange 0,8ohm

Black-gray 1,0ohm
Black-brown 1,0ohm
Black-red 2,6ohm
Gray-brown 0,5ohm
Gray-red 2,1ohm
Brown-red 2,0ohm

How to connect 230v?

Hi,

I've just entered into the world of DIY tube amps by bringing a old Audio Innovations gen1 800 series back to life.
Only two hours ago, It played music for the first time in years!

The amp was bought second hand for the transformers and some bundled Telsa NOS tubes, still I decided to attempt repair before scraping the original PCBs.

Anyway: The amp shows clear signs of having had at least two instances of all tubes being damaged, prior to me repairing it, now for the third time.
I need advise on how to prevent this from happening again, as PCB and wiring was barley savable this time and next time the amp will definitely be history.

The damaged components indicate the failure mode is as described here: Audio Innovations
quote: "....the EL34's do their special internal short-circuit trick and destroy the cathode resistors (those who have seen their output valves glowing like fluorescent carrots before the sound expired on one or both channels ..........."

Is this an issue particular to Audio Innovations or is it general for EL34 tubes running UL Class A?

Diagram can be found here
Are there any precautions I can take to increase life expectancy of my latest pride amplifier?

Instead of EL34s I'm now using TAD 6L6 WGC-STR tubes. Matched Pairs for both left and right channels. Paraphase phase splitter is using no-name 12AU7 and input stage is Phillips Miniwatt ECC83.
There used to be a large difference (approx 10%) between Cathode resistors for "Push" and "Pull" sides. These are now within 0.5% of 395ohms.

Cathode decoupling caps had busted and are now replaced by 100V types.
Burned out grid stopper resistors on the "UL" grid has been replaced.

Unloaded B+ is 400 volts. I have not been able to measure B+ under load.

Any other measures I should take?

Thanks
Lars

A pair of woofers in very good condition. Home use only, no PA. Different color of cones due to different production date.

260 euro pair. Located in Sweden.

I would like to buy 5-10 pieces of LME49990. If anyone still have some for sale, I'm very happy to take it. Thanks.

Hello!

I have received a Carver M500 that blows its main AC fuse at power up.

Studying the schematics and looking inside, I notice evidence of previous cap replacement except the solder joints on the two biggest black caps looks original.

Yet, the orientation of one big black cap seems reversed: C509 should have its Neg leg on the Neg trace below--but it doesn't seem so; it appears they both face the same way:

Shared album - Daniel Martinic (Dan) - Google Photos

Mind you, the one in question is oddly turned about 30 deg.. not sure if that's usual.

Should I unsolder this cap and turn it?

Hi,

I have a little room (W)2.38m x (L)2.50x (H)2.70m with some acoustic treatment (2" Owens Corning SelectSound® Black Acoustic Board) in the front and back wall, and I am trying to learn to use REW's Room Simulation to get the proper location for my subwoofers (2x).

My questions are:

-. What I am trying to achieve here? The flattest frequency? Or just to lower the modal resonance lines? A peak its better than a null, as it can be equalized?

-. What is a "good" graph? At some models I have peaks of around 20db, and at others it's much flatter but at lower db. Although a total flat graph it's not achievable.

Thanks in advance!

I'm new to this forum so please bear with me with my lack of knowledge, that is why I'm here after all ☺️

I currently have a Bk monolith plus sub which I'm very happy with and want to add another one. This is where my problem begins.

My wife, who has been incredibly tolerant over the years with my hifi & home theatre purchases has finally put her foot down and said NO to another monolith plus. Not because of the expense, to use her words "were not having another big black monstrosity sat in here".

So, we came to a compromise. If i build two subs and make them look like side tables (walnut veneer, the works) she will be happy with that. I'm no stranger to joinery and confident in my skills, also having a brother as a joiner helps!

The subs are for home theatre only.

My initial thought is to use the same driver and plate amp that go into the monolith, but I'm hoping for opinions and suggestions on drivers and amps. I've been comparing drivers, cabinet volumes and port sizes in Winisd to get ideas but I'm no expert!


The maximum cabinet size I can go to is 18.5"W x 19"H x 32"L and would prefer them to be downfiring, vented subs keeping to a similar tuning as the monolith.
Budget around £1000 for the pair.

What do you think?

have come across a pair of ACS-340 Subwoofers and a pair of ACS-295 Satellite speakers. The Woofers have an 8-pin mini-DIN input receptacles and the Satellites have 7-pin mini-DIN plugs. Anyone have a schematic for either the ACS-295 or the ACS-340 systems?

I would like to "marry" the 295's satellites to BOTH '340 subs for a TRUE stereo subwoofer setup. In my humble opinion, bass is not as non-directional as some would have us audiophiles and DIYers believe.

FYI, the ACS-340's specs are as follows:

Satellites: 13W for both channels (I assume this is 6.5W/Ch)
Mono Sub: 27W total (Probably 13W x 2 channels.

I do not have specs for the '295 satellites.

I have to assume that even these systems have rudimentary active crossovers, and if they do, then I maybe I can take advantage of "retro-fitting" them for some reasonably good performance.

I have tried to contact Altec, but they do NOT release schematics.

Anyway, any help would be greatly appreciated.

Thanks and '73,


Steve

Hi amigos,

I am in the process of making a new double MONO Class D Amplifier.
I got two mono 300W Board with a LLC 800W PSU double rail 60VDC.

I wonder what is the right wiring ? Picture 1 or 2 ? if other, can you correct in the below pictures.
unfortunately I did not find any assembly instructions...

I can't seem to help myself
I just couldn't resist stopping to pick these all up Yesterday
I have no idea what I am going to do with all of them but the small boxes will soon be speakers for the 11YO Grand-daughter.
I hate building boxes because my woodwork sucks and the speakers I was building for the femme was vetoed by her mother because they were too big, these little ones might just pass muster tho
Your average big box cheap Chinese speaker system but the Teac subwoofer seems to be working
Fortuitously the little 4" woofers I like to play with are a prefect fit in the woofer hole, all I need now is to find a suitable tweeter, I really don't like those $2- Mylar ones at all

Hi

first time posting here, though I we been lurking for some time now 🙂

Was looking for a FW amp for my Omens for some time now, but living in Europe they are relatively rare - and pretty expensive, even 2nd hand (especially J2). Economy being what it is i decided to go DIY way and try to build one but I am unsure which one - F6, F5 or perhaps even Aleph J. From what I read it seems that F5/F6 have more authority over bass (which I fell Omens need); though on the other hand there are some that praise M2 for its tubesque qualities - which usually work well with Zu's. Essentially I would be grateful if you have any input and or experience with the said - or similar speakers - and FW amps.

All the best

Gordan

Hi out there!

I have two identical 5.1 systems that doesn't work (I think the problem in both are the power supply, but I don't care about that, I'm interesting on reusing the drivers, they are working fine). The pair of 5.1 sets are logitech x-530 models, detailed specs: (Logitech X-530, Continued - 5.1 Surround Sound on the Cheap | Tom's Hardware).

I have the idea of reusing the satellites drivers and the subwoofer of each old system, to build a pair of stereo two ways speakers. I want to build two boxes to accommodate the 10 small drivers for mid/high frequencies, and install the sub to cover the low frequencies. I would buy a pair of two ways passive filters to separate the frequencies (2 ways passive crossovers). I will power the new resultant speakers with a regular 2.0 channels amplifier (38 RMS watts per channel, 4-8 ohms capable).

I have some questions about this project:

1.- how can I wire the 10 small speakers to connect them to the high-pass filter with a total of 4 or 8 ohms resistance?
2.- What point do you recommend for crossing frequencies with these drivers?
3.- Do you miss any aspect in my thoughts about this project?

Many thanks!

Hello

I have a marantz cd4000 cd player which has been in storage (dry, safe) for several years and was working when went in...now I am wanting to use it, its not responding at all when plugged in - nothing on screen, no response to keypresses, I can hear a slight hum so internal transformers may be active...
I have downloaded schematics and will try to test power distribution - just wondered if anyone had seen anything like this and maybe there's a common cause (e.g. a fuse or weak connector) - also any tips on where you would start looking for the problem would be welcome!

Cheers
John

SOLD, thank you for your interest.

Hi, I have some Class A pcbs to sell. Prices are marked at a good discount already, but all offers considered. Shipping is not included. Shipped from Western Canada.

Image 1: Alpha 20 pcb. I have 2 pairs of these with pads and 1 pair without pads. $30 USD / pair.

Image 2: Dual Rail SLB pcb. I have 6 of these. $12 USD / each.

Image 3: ABBB pcb. I have 2 of these. $75 USD / pair.

Image 4: Alpha BB pcb. I have 2 of these. $45 USD / pair.

If interested, please PM me. Also have a look at my other 3 threads posted earlier for some other deals on Tube, Class AB, ClassD pcbs.

Regards,

Myles

Greetings all!

Im a broke 21 year old college student from Illinois and im usually active on the audio karma forums. I avoid posting here because the site to me is cluttered and confusing, however it seems there are more people on this website and more participation in the threads and just more in depth knowledge in general.


I am planning on getting a CNC mill soon and want to start making flat pack DIY kits for horns to sell to people, and would love to make some two way and three way systems, I just need to know where to start.


Im only 40% through with my degree in mechanical engineering, so my grasp and ability to understand papers and technical mumbo jumbo (which people have showed me and I have read) isn't that great. Its like a can partially grasp what I read on horn design but not fully.

The smartest people are really, the smart people who can explain things in a way easy enough for the common folk to understand it and im hoping one of you are good at this!

What is the best horn geometry? I realize that some horn types are better than others depending on the situation, and wanted to list all the pro's and cons of the different types fo horns.

Ive narrowed it down to 3 designs
can anyone give me a simplified explanation or list of the pro's and con's of
Tractrix horn
Bi-Radial Horn
Conical

any help??

Hi Guys,
Are there better sounding caps then the Styro's.
Using it to shunt HF. Notice that different brand
different sound. Overall it's a little too zinggy for
my taste & bright sounding. Toshin have some
PPSD which are cooper foil not cheap & wondering
if it would be better.
Perhaps you guys can advice on other types.
Btw Silver mica also not for me tried Soshin.


Thanks in advance

I received a book for Christmas and I'm delighted with it. Thought I'd pass the information along.

"Vaccum Tube Amplifier Basics," by EJ Jurich, Fourth Edition. I got the large paperback edition, but there is also a Kindle edition available from the usual places. Very inexpensive.

This is a book aimed at newbies like myself. It explains in clear and concise language how a tube amplifier works, but it's more than dry theory. It contains formulas throughout for calculating resistor and capacitor sizes, how to select a transformer (power and output) and explains different theories such as cathode bypass capacitors, negative feedback, ultralinear design and so on.

It explains and diagrams how to read the kind of schematics one finds on the web, explaining differing styles of notion and layout and what they mean. It shows the symbols for different types of devices, such as caps, pots, resistors, and so on. It explains how they are constructed in limited detail and how to decipher the values from the writing or colors on them, including 'old style' values.

It also talks about mechanical design, layout and construction, with diagrams and photos as well as the schematics for the circuits being built.

It also contains some common tube data at the back of the book, but more importantly, explains what values are important and what they are used for when designing a circuit.

There is a chapter on instrument (guitar) amps, including a project amp one can build, but it is mostly focused on hi-fi uses (although of course there is a huge amount of carryover between the two).

The book has several complete projects that one can build, including an SE 6V6 amp and a RIAA phono preamp and so on. It has some tone controls and explains how to design and then insert them into a circuit.

This book would probably be 'old hat' for anyone who has been building for a long time; most would probably already know this material (and might have differing opinions on some of it). But for newbies such as myself, this book seems to be exactly what I needed for now. Until I become much more advanced, this is what I was after.

One word of warning; the author appears to have a firm belief that expensive components are generally a waste of money and states it at several points in the text. Whether one agrees with that assessment or not is a matter of taste; I merely point out that it is present for those who have a visceral reaction to such statements.

I hope everyone is having great holidays and I thank you for the help you have already given me. Perhaps this may help to give back in some small way.

Hello!

Really sorry for long post, i tried to keep it short and detailed. Hope some kind person can help me out, i tried to search clips on youtube and various threads here but i just can't seem to you know.. Decide

I need some help with choosing speakers for my little room. And when i say little its really small, dimensions: 1,75x2,75x2,30 ^^

I want to make a cheap system around 50-150USD if possible.
I have amp (citronic plx 3600) and 5band mixer collecting dust. However i dont think i want to use PA speakers on this but unless you feel like i should then go ahead and please tell me why 😀

I listen to everythyng, but mostly powerfull rock or metall
So aiming on a system that will play rock, heavy metal. and if possible id like to feel the punch in my body but maybe that is hard to achieve with this price tag. If that is the case then please let me know and i will go higher

Biggest outer dimension is 30cm in width, speakers will be placed on a table 1 meter away, I feel like there is room for a 10" bass driver

I have built a ported subwoofer box before which actually turned out really good. so im atleast not completely new to the building part. I've dabbled with my car audio for 10 years but never really dived into this hi-fi world like i intend to do now gradually.

This is my first system so i just want to try it out and take it from there



But like i said in the beginning, i need help choosing a crossover and a set of speakers that work well for the specifications above
Is there kits that can be found or can you point me in the right direction maybe?

If you have questions just fire away and i will get back to you asap!

CS4396 Based DAC that had the output OPAMPS removed and Sescom M-14 Transformers installed for balanced out. I built this years ago - used it for quite some time until I started using my Wolfson based DAC...

To keep everything intact, I encased all of the delicate circuitry in hot glue...works great.

More info on DAC

Experience with this DIY DAC ?

$75 + ship or pickup in West Sub of Chicago?

Good morning everyone, friends, this time I come to ask you for help, an amplifier of the soundstream brand has arrived again and in my last experience I had with another like it, it went wrong but this time the failure is that I have frequency very low in the output fets of only 16khz, what I have been looking for is how to increase their frequency ?, I have seen them working at 118khz in advance greetings

I just finished building the PS for my F6 project. Using the Universal Power Supply board, I stuffed it with parts from the BOM in the build here:
https://cdn.shopify.com/s/files/1/1006/5046/files/P-PSU-1V30-bom.xls?15967766640867126881

I'm using an Antek AS-4218 (400VA, 18V).

I'm getting 26.8 volts out of each side. I was expecting 24.

Is this going to be too much for the F6? If so, should I chose differs values for R1 through R8?

BTW: I'm using 25V 15,000uf caps.

Thanks,
Peter

Victor

The amp fired up without a hitch, sounds wonderful through my La Scalas, thank you for everything.

Was just shared to me by my wife
WOW!
No Dialogue, Just a Guy Woodturning This Into a Speaker <<TwistedSifter
Not my cuppa tea but nice work
Anybody know what the innards were?

Hi.

Hope everyone is managing OK through this crazy time.

Helping a friend build a switch box for his system.

Here is the challenge...

There are two sources in his system. A turntable, and everything else...

He has two phono stages. One Tube with volume control (EAR834P) and a solid state one.

He wants to be able to switch between the two pending music played. This part is simple...

As the solid state Phono Stage is fed into a different preamp, and the EAR834P is bypassing it, they need to be isolated from each other. Still simple.

Both the the signal paths go through a High Pass filter in all cases to the Amp.

The signal is also split prior to the high pass from both sources and is sent to the Subwoofer.

The signal paths here also need to be separated from each other.

Getting more complicated.

What I am hoping to do is do all this switching with a single rotary switch, and put the switching as well as the high pass filter in a single box solution.

Too many wires running around the way it sits now...

I've attempted to draw a breakdown of how the flow needs to happen. Hope it makes sense...

Option 1 is using the EAR834P, Option 2 is running it through the SS Phone Stage.

How can I achieve this with a single rotary switch? Don't want to have three separate switches for him to have to flip back and forth.

Thanks!!!

P

Hi guys I have a question about Mrspeakers Alpha Prime. To my knowledge it uses dual 4 pin mini xlr, but T50rp only have 2 cables per channel. How is it wired? The connector is E-Valucon SN-8-4(R)

Having fun trying to amuse myself since the lock down started. Figured I was line stage poor so I started drilling holes and putting stuff together or I should say mocking it up. Waiting for parts to arrive but I can share what I have so far for your criticism.

Aikido 6Au6/5687 And Aikido 6SJ7/6SN7 with 5693's and 5692's in the sockets.

Hi there,

Picked up a Sony XM-3060 with a missing RCA shield, hoping it would be an easy fix. Well turns out not so easy finding the 10 pin RCA jack that Sony used. I checked all the other RCA"s I had to see if I could remove a shield and pop it on with no luck. I can find 9 pin RCA's that look like they may work. As far as I can tell A-F are the positive inputs and the three G's are the negative shared ground. I don't believe the tenth pin between D and E does anything

here's a couple possible replacements?
thanks for your time

Amazon.com: uxcell AV Concentric Outlet 6 RCA Female Jack 9-Pin Connector Socket Panel Mount 5pcs: Electronics

Input RCA jack for HiFonics, Autotek, Crunch,Lanzar, ect | eBay

I’m servicing my M-120a power amp that had a noisy right channel. Swapped out a 2Sc2240 and 2SA970 in the input stage - seems to have fixed it.

These two components are on a part of the PCB that appears to have suffered some long term heat damage - nearby a 1W 39k resistor that seems to be the culprit.

Interestingly the service manual states this as needing to be a “flameproof metal film resistor”. I’m tempted to just replace with a 3W normal metal film resistor, and mount this on the reverse side of the board to keep heat away from other components. Any problem with this approach? What’s different about flameproof specd resistors apart from obviously not catching alight if overheated? Do they behave differently when heat stressed? Do they fuse? Should I be using one as a replacement?

True, she's not much to look at. It was my first project and I was expecting it to blow up when I switched it on for the first time so I didn't put too much thought into the cabinet, or anything much really, as you can see. But it worked a treat from the get go and I loved the sound so much, and was lazy, so there it stayed for nearly ten years.

Now it's dead.

First the right channel would drop out sometimes, then reappear. Eventually it stopped working altogether. I put it down to ten year old tubes so I replaced the lot. No change, still just the left channel. Then that promptly died too, and the fuse blew.

I've turned it upside down and got the toolbox out, but it was a long time ago and I don't know what I'm looking at any more. I've checked obvious things like physical connections and they're fine, or at least look it. Nothing obviously cooked that I can see. I'm just about to remove the board and have a look at the other side.

Hi everybody

Currently have a marantz cd4000 everthing works fine apart from
the display says no disc the disc does not spin just twitches a fraction stops and twitches again

Is this a simple vam1201 replacement or could it be board trouble instead .

The laser has been cleaned once with a dry brush disc and with alcohol on a cotton bud still same....

Appreciate any help as dont want to waste money on laser

I used an idea from Sam's Linear Audio article, keeping Vds ~2.6V, and using an APV1122 MOSFET driver to bias the CPH5905 JFET.

Unfortunately I left the generator on so there is some pickup. Gain is just under 20dB. 1/f noise doesn't look that great.

Please stay tuned..
Full review of TU-8800 with Lundahl will be available soon..

Doctorjohn Cheaptubeaudio: Audio Reviews and More: Elekit TU-8800VK Lundahl Tansformers Tube Rolling TU-8300


Review: Elekit TU-8800 (VK), Part II, Lundahl Transformers, Tube Rolling
Review: Elekit TU-8300, Part II

Elekit TU-8800, Part I (has a pic of stock output transformers; tested with LS3/5A)
Elekit TU-8300, Part I

Klipsch Heresy Part III (for system description and general characteristics)

Note: This is a very long article, particularly the section on Tube Rolling. You may want to jump to the section(s) that interest you the most.

Prologue After I wrote my Elekit TU-8800, Part I, the LTA MicroZOTL arrived and I basically just got deeply immersed for quite a long while. This article is mainly about the detailed tests I am doing now. But in the interim I did re-visit a bit. with YL Horns I did pair it up briefly with my (104 db) YL horns. With the Siemens Top O-Getter 12AT7 and current production Russian "Genalex" KT88, the sound was somewhat too sharp, especially at high volume. This was interesting to me as the same tubes worked very well with my much less efficient (87 db) LS 3/5A's. I took this to mean a little too much power/gain for my horns. 6V6 I then swapped in my RCA 6V6's. Sound audibly improved but was still not entirely satisfactory. I then got diverted by other things. Used as an amp/Gain Issue As I usually have too many sources, I almost always use these Japanese amps (just an amp with a volume knob) as amps, preceded by an active preamp. With Elekit TU-8800, as with my TU-8300, the gain is very high, so the volume knob could not be turned up too much. Even then I encountered a unique problem: occasionally, with a dirty LP, a loud click or pop was enough to trigger the protection circuit of the Elekit, which would then mute itself and the green indicator lamp would partially turn orange red. Turning it off and on again would regain normalcy. This indicated to me again the issue of gain and the amp would better be used as an integrated amp (or as an amp with a passive preamp or TVC). This has happened with my TU-8300 before too.

This unit of TU-8800 is a fully assembled loan unit from vkmusic. I was told it is bone stock except for 2 coupling caps.

With the Klipsch Heresy I System
So, now that I have set up my living room system, I set out to do more testing on it. For those not familiar with my Heresy system, please first read the Heresy link above. A brief re-cap of the system:


Turntable (stereo): Thorens TD-124 Mk I with Thomas Schick 12" arm and Goldbug Clement II MC Cartridge.
Turntable (mono): Technics SL-1200 Mk II with Denon DL-102 Mono Cartridge。
Phonoamp: Arcam rPhono (to Gotham GAC-2111 interconnect)
CD Player: Magnavox CDB 262 (to Gotham DGS-1 interconnect)
Amp: Elekit TU-8800 (Belden 9497 loudspeaker cable)
Speakers: Klipsch Heresy I (alnico)
Subwoofer: Pioneer SW-8 (connected to amp with generic cable)

I started with the same Siemens 12AT7 and Russian KT88. It was immediately apparent that the sound was better than with the YL horns. It was already enjoyable but a little more sweetness in the massed strings, particularly when they really dig in (this is very challenging for systems), would not be amiss.

Pearl
12AT7 First, I swapped in a pair of old-stock GE D-getter 12AT7, and the sound immediately and considerably sweetened. The massed strings now only had a trace of the metallic about them. The soundstage moved back quite a bit. Yes, I lost a little resolution but I got more music. This confirmed much of what I believe of Siemens tubes - many of them are forward and lean (almost transistor-like sometimes) and are best used in vintage systems that are overly warm (usually not in spec).

Output Tube Rolling It is not often that I have the time to do much tube rolling. I usually do the minimal necessary to get the sound I want. With more time on hand at the moment, I decided to do this review justice. I randomly pulled out a few types (all old stock; see pic at bottom) to test. I tested them in no particular order, and as I went along, I pulled out more and more tubes. So this is a lengthy read. I shall also talk more about these tubes after I finish the review proper, to make it yet lengthier. You have been warned.


6V6GT Then, I dropped in a pair of RCA smoked glass 6V6GT (lowering the output to around 2 watts; remember to switch the Power Mode to Low) and the sound further improved. Now, I could play anything. It doesn't have the grunt of the KT88 but the power is enough for me even in this large room for Arethra Franklin's I never loved a man the way I loved you and Janis Joplin's Pearl. No pounding bass but the full impact of the music comes across loud and clear. Those 4 live bonus tracks (1970 Canadian Festival Express Tour) in the Joplin CD are even better than the album proper; the immediacy is life-affirming! Similarly, Celibidache's 1969 performance of Bruckner's 4th with the Swedish RSO (DG) is coherent and compelling. Now, all these albums mentioned, though reasonably well recorded, do not belong to the top tier in audio quality, but musically they are compelling. Triode/UL I tried both again and found the difference in sound quality as well as nominal power much less than expected (probably more apparent with higher powered tubes) and so left the amp in Ultralinear Mode. vs LTA MicroZOTL The Elekit with 6V6 is roughly in the same power envelope as the LTA. But, as expected, the LTA has a more naturally fast transient and reveal more rhythmic felicities and subtleties.

6550 I next dug out a pair of old-stock 3-getter Tung-Sol 6550 (this is a very fine tube, best of the 6550's) and installed them. By now I was listening to Rudolf Serkin playing Mozart Piano Concertos (with Abbado; DG). A repeat showed the sound to be further improved. The soundstage is larger and there is more detail compared to the 6V6GT. It is still quite smooth. Then I found out I had not changed the Power Mode before the swap (still in Low Power Mode). I turned off the power, changed to High Power Mode and turned it back on. Even more air and definition. I replayed the Janis Joplin CD. Surely it sounds more punchy, more controlled, and the vocals and instruments become clearer. An unqualified success. It got so good that I played Hugh Masekela's Hope and played a few track with relish. The attack and presence of the Heresy is highly gratifying (the non verbal expletives highly stirring), and the percussion and bass are very decent. The audiophile's favorite stimela plays with momentum, virility and satisfactory slam. Of course, again, with the 8" subwoofer, when it comes to bass it is not as good as my YL's 15" woofer, but it is satisfying enough and tightly argued. I'd not think of playing this track with 2 watts (6V6) for enjoyment (testing is a different matter). But it is not all about impact; the system brings out all the atmosphere in Nick Cave's The Boatman's Call. In this outstanding album, the mournful, the confessional and the spiritual create a groove of their own, as powerful as any uptempo material. Sparse but beautifully shaded instrumental effects punctuate the landscape established by the moody keyboard and Cave's voice (one thing I like about him is his clear vocals; you don't have to read the lyrics). Yes, horns let you feel the mood better than conventional transducers. So far so good.

Nick cave and the bad seeds-the boatman's call.jpgPower Mode I want to take the time here to emphasize the importance of checking this when one changes Power Tubes. The amps has 3 positions: LOW (6V6, 6F6); MID (6L6 family, 7591, EL34) and HIGH (KT66, KT77, KT88, 6550, KT 120/150). When I changed to the 6550 (above) I by mistake (using the 6V6 setting previously) started with the LOW, which gave it a softer sound because of the lower B+. That was OK. BUT, if I now want to swap back to the 6V6 and forgot to set it back to LOW, I would likely run into trouble as now I'd be running the 6V6 at too high a B+, even if I am sure Elekit runs the amp conservatively. Keep in mind you can safely run a power tube at a lower B+ (with a change in sound, as per my experience) for fun and experiment, but not the other way. I am not sure whether I can do this on the fly, so I didn't try. So, always check.

5881 This is a rugged 6L6WGB type that can withstand higher voltage (as per instruction, I used the Mid Position). The pair are Tung-Sol's, even if one is marked RCA. Here I got my first disappointment. It has neither the sheer brilliance and output of the Tung-Sol 6550 nor the musicality of the RCA 6V6.

EL34 Keeping the Mid Setting, I swapped in a pair of Mullard xf2 EL34 (labelled HP). The sound is very good. It sounds detailed and powerful, enough to almost rival the Tung-Sol 6550, yet is musical enough to rival the RCA 6V6G. In fact, it made the 6V6GT sound just a little veiled. It is also a little smoother than the Tung-Sol 6550, which likely means different things to different people. To the average vintage lover who crave tube warmth (usually overly so) that is great; but to someone like me the leading edge is just a little too rounded, making the sound, sweet as it is, not as life-like, and isn't that the primary goal of horn users? But one can see why this tube is popular in SE amp configuration. My first SE amp was the first generation Audion Sterling over 20 years ago, and it was a good sounding amp. Later I got into Direct-Heated Triodes, and one of my 300B amps was again the (first gen) Audion Silver Night. There is no doubt in my mind about which Audion amp is better.

6V6G Given the findings above I set my sight on testing more 6V6 types. I wasn't thinking of 6L6G but I chanced upon a pair of Zenith 6V6G and used them (Low Setting). An utter surprise! It gave a mesmerizing, flesh-and-blood performance! It is not the surprisingly detailed sound that is so impressive. Images are larger and more palpable. In the Nick Cave album, the second half is a little less somnolent than the first, and there are more instrumental flourishes, which I dig (including a violin). In Idiot Prayer, Nick Cave's voice acquires more gravitas and urgency, and the various instrumental flashes have the truest timber (nowhere is this more apparent than the pizzicati). The most impressive thing is, good as some of the other tubes are, this sets down the mood more effortlessly. You don't have to get it; it gets to you. Downside? Yes, for the first time I hear some clipping in loud passages. This is known, the G has lower power rating than the GT. But for simpler music (I count this Nick Cave album among them) it is hard to best.

6L6G Inspired by the 6V6G and, given the uninspiring performance of the related 5881, I swapped in a pair of RCA smoked glass 6L6G. Mind you, the 6L6G sounds magical in my WE 124B amp, albeit in push-pull. As expected, the sound is very good and has much of the same qualities of the 6V6G. But there are differences: it is slightly less detailed; the images are a little less fleshy and the instrumental timbers a little sweeter (not to the extent of EL34). While in terms of presence it is edged out by the 6V6G, it has the advantage of more power (doesn't clip). A very fine effort.

6V6GT/VT-107A I continued my 6V6 testing by swapping in an older pair of 6V6GT that is also marked with the military designation VT-107A (the RCA logo is also larger). In my experience, early VT- designated tubes are usually superior, and it so proved. Compared to the first pair of 6V6GT I used, it upped the game considerably. This older GT tube has a little more detail and even better presence, dynamics and flow. Like the other pair of 6V6GT, images are smaller and it is less dramatic than the 6V6G. It has the advantage of greater power and is quite effortless with most material. Overall performance is excellent.

KT66 The sound of the (old-stock) GEC KT66 proved yo be as fat as its profile. It is a rich sounding tube, even smoother than the EL34, but its transient edge is even slower. It is obvious the Nick Cave album moves at a more deliberate pace. Of course, presence is not its strong suit. When I replaced it with the VT-107A I was immediately revived by more air and pace.


KT88 Now, although this amp has 3 power modes and allows you to use all kinds of tubes, I suspect it was voiced with KT88, as it is the only tube marked in bold on the Power Mode sticker label. So I was curious about the old-stock GEC KT88., made by the UK to counter the high-powered US 6550. The US never made this tube, and in my experience all latter-day and current productions don't hold a candle to it (as evidenced here by the Russian "Genalex"). Sure enough, this excellent (and very expensive) tube performed wonderfully, very much in the vein of the 6550, though a little warmer and also a little less excitable. With all the power available (like the 6550, the chassis is notably warmer than when the 2 lower power modes are used), Chabrier's Espana (Ansermet, London) was well controlled yet crackled with excitement. With plentiful air, this tube effortlessly separated the various strands in the back-up to Cave's vocals, and the violin and pizzacati are truthful. Compared to its British cousins EL34 and KT66, it does less beautifying, and has better air, leading edge and transients. Although it is still not as neutral and doesn't convey the mood as well as the best of the 6V6/6L6 family, it is still highly musical and has more power to boot. Wonderful!

Back to 6L6G To check on myself, after the very good performance of the KT88, I re-installed the 6L6G and, sure enough, I stand by my words. Whether it is the vocals or timbers of the various instruments (like the burst of the Hammond or the wail of the violin), this tube is still more truthful than the KT88. And the music moves along even more. And, yes, the mood. I firmly know, for me, since I can get away with it, I'll stick with 6L6G, 6V6G and VT107A.

Back to VT-107A At the end of tube rolling, I re-installed the VT-107A, and the impression is the same. This is the tube I am going to use day-to-day.

Enter the TU-8300 (pics at bottom of article) At this point I swapped in my TU-8300 (see Part I). Design vs TU-8800 The two amps have a lot of similarity. The first half of the 12AT7 is capacitor coupled to the second half, which then is capacitor coupled to and drives the output tube. Both amps employ feedback from the 8 ohm output tap. Both amps have protection circuits. The biggest difference is that the TU-8300 is Triode only (for 300B as well as medium to high powered beam and pentode tubes, such as 6L6GC, EL34, 6550, KT88, though sadly not 6V6) whereas the TU-8800 is switchable between Triode and Ultralinear and can also use low powered tubes like 6V6 (but no 300B). Of course, due to the ultralinear feature, the output transformers of the TU-8800 require extra taps and are more expensive to make. It should be noted both amps belong to Elekit's top offerings. The older 8300 does not even have an earphone output, and has only one input (a nuisance). The 8800 is much better ergonomically, has 2 RCA inputs (one wired parallel to a minijack input) and does have an earphone output connected to the transformer output. Unlike the desktop-driven design of TU-8150 (here), for someone like me who use only the RCA inputs, these extra's do not interfere with the signal path. 8300 Mods As mentioned in Part I, I did some modifications to the TU-8300 (pic at bottom). I replaced the input RCA sockets, hardwired the input with Belden 8451, changed the potentiometer to an older generic type (unlike others, I regard older designs as better, and they are really cheap) and hardwired it to the circuit board with the conductors inside the same Belden 8451. I also changed the two coupling caps on each side to Russian military PIO. Earlier, in an attempt to lower the input sensitivity, I had wired resistors to the input but I later took them out as it was not very effective. The resultant sound is a little warmer than the original. Used as Integrated Amp As discussed at the start of the article, due to high input sensitivity, both amps are better used as integrated amps. For the purpose of this article I did that for both amps. For the 8300 I had to change cables when I switched sources. I had actually never previously used the 8300 as an integrated amp. Used this way, it is actually much quieter than I thought. 300B I started with the Shuguang 300B. Initially, I was taken by surprise. Using the same albums, the vocal and instrumental placements in the soundstage were noticeably different than before, the color was darker, the bass was muddy and things fell apart with orchestral tutti. I was not happy and after some thought swapped out the Mullard 12 AT7's and swapped in the GE's I had been using in the 8800. Good Lord! Now the 8300 with the 300B sounds almost identical to the 8800! A lot of people go for Mullard, but not me. Aside from a few specific types, it has its own colored, usually fat and veiled sound. The GE sounds much more neutral and correct. Thus tubed, the 300B turned in an equivalent performance to the best of the beam/pentode tubes. I expected this, as imho the 300B is one of the few successful modern tube production stories (of course NOS true WE300B is better, but that's untouchable). Russian KT88 Satisfied, and as I was not going to do all that tube rolling again, I just tested what I started with, the Russian "Genalex", and the result was pretty good, much as it performed in the 8800. Pointers vs. 8800 Keep in mind the 8300 had been modified to yield a warmer sound, so it is right to conclude the 8800 is a little warmer than the stock 8300. Even more obvious, although the 8300 is quite quiet, the TU-8800 is dead-quiet. With some of the tubes, there is no noise whatsoever; with some others, there may be a little noise, but I am confident it is tube noise/rush. Keep in mind with 97 db loudspeakers tube noise is an issue.

The Lundahl Transformers!
And, now gentlemen...the high point of this review. It is not every day that one gets to compare transformers! VK of vkmusic is a perfectionist who for the longest time has been offering upgrades for many of the Elekit kits he sells. These were usually capacitor and resistor upgrades (some of the resistors had to be custom made). Since the acclaimed TU-8600 300B amp, VK Music has gone further, offering upgraded transformers in cooperation with Lundahl. It is an arduous and time consuming task. VK informed me that the final version has three previous prototypes. In the top pic you can see they are even beefier and heavier than the stock ones. Installation This proved to be a bit challenging. It was not difficult to remove the stock transformers and wires, but the metal bracket they are mounted on was a problem. This is because there was not enough clearance on the right side of the chassis to allow lifting of the bracket. And because the screws of the Lundahl transformers have to be mounted from the bottom (see pic). I did not want to do the unsoldering needed to remove the circuit board. What I did was to stand the chassis on its right side. This way the bracket can be tilted 45 degrees from the chassis, allowing tight room to work (especially with the right output trans). I first got the screws in with my hand holding just the bit, then use a 90 degree screwdriver for the final tightening. The obvious message is it is much easier to have the upgraded trannies when one starts to build the kit! If not, one can upgrade with a little more effort.


Cover shows a close up of Cash's face, looking at the camera.TU-8800VK--Sonic Impressions I continued to use the GE 12AT7, the Low Power Mode and VT-107A. Brand new transformers take quite a while to run-in, but I'll cut to the chase: Now I am at around 30 hours; even without much run-in, the Lundahl Transformers are a significant Upgrade! From the first note of the Nick Cave album I noticed the difference. I replayed every album and also a few new ones. How one transformer is better than another is sometimes a subtle (but very important) thing that is hard to describe, harder than say the difference in sound between resistors or caps. Changing the transformer changes everything and it is hard to separate the impovement into components, but I shall say a few words on the sonic merits:
Ease of Flow Elekit, especially the 8800 (and the 8300), has a neutral and resolving sound. With the right tubes, as described in the tube rolling section, the flow can be impressive, but with the Lundahl's, it is significantly enhanced. This is as true for Nick Cave as for classical music. Paray's Dvorak 9th (Mercury CD) was as exciting as ever, yet totally non-grating. To me, better ease of flow is at least partly due to better microdynamics. As in real life, ease is a precious thing; unlike in real life in this case you can for sure buy it with money.
Enhanced Bandwidth This is immediately obvious and the most objective parameter. There is more air in the treble and a cleaner, more tactile, yet punchier, bass. It changes Nick Cave's vocals and the piano tone, now even clearer (sometimes even ethereal) and more resolving. All the instruments have more sheen. In classical music, it is obvious the soundstage is also significantly deeper and airier.
Sweet Presence Generally speaking, presence, or the feeling of a live performance, requires a fast transient attack (and horns) and can come at the expense of a little sweetness. Not so here. The Lundahl, even with increased bandwidth, makes everything sweeter, yet presence is enhanced. Johnny Cash At Folsom Prison (Legacy) is an excellent live recording. Here, the audience is perfectly captured, Cash's voice smoky, the guitars sweet and beautifully delineated. In Jackson, a duet, June Carter is just dynamite!
More Forgiving of Tubes As you have read from the Tube Rolling section, I roll tubes a bit to find out what I like (usually a neutral sound, but it has to convey presence and mood). Given the increased ease in sound, I suddenly had the idea to give some of the tubes I did not quite like before another shot. I rolled in the Russian "Genalex" KT88 and, surely, the performance is significantly better than before, less etched when the going gets rough. Keeping the output tube the same, I then tried out the 12AT7's which are so critical to the sound. The Siemens 12AT7 is still a little forward but it is now quite acceptable. The Mullard 12AT7 is still a little too dark and veiled for my taste, but it also performed very well. So, "rolling" transformers is even more effective than rolling tubes, when done right.
TU-8800VK--Earphone Tests I use earphones only on occasion, so this is brief. I first connected my Beyerdynamic DT880 (97 db, 600 ohms) and listened with satisfaction to Otto Klemperer conducting the Philharmonia in Dvorak's 9th (Angel, LP). But when I played the Nick Cave CD I realized the proceedings were a little heavy and the bass not well resolved. I was sure that is an impedance question, and so switched to the lower impedance AKG K701 (105 db, 62 ohms). Sure enough, that immediately cleaned up the sound and improved the flow, and now it resembled the sound via the loudspeakers. I see there are internal 6-position dip switches that select resistors, surely for impedance and level matching, but lacking the manual and not willing to open the chassis again I will leave it at that.
Comments on TU-8800(VK)
Stock Version As I'd expect from Elekit, the TU-8800 is a very capable amp. A decade on from the TU-8300, the TU-8800 is a lot more versatile and ergonomically desirable. As I'd also expect from Elekit, it is a very neutral amp that reveals every change in tubes and components. Even with current production tubes, it turns in a very good performance. Highly Recommended.
Lundahl (VK) Version The million dollar question is, at a premium of roughly half the cost of the stock amp, is the transformer upgrade worth it? Experienced tube users, especially vintage aficionados, know just how important, and how costly, good transformers are. Personally, I am very impressed by these Lundahl transformers. They confer abundantly that most precious Final Touch, and that elevates a very good product to an outstanding one. A lot of DIY people spend a lot of money upgrading caps and resistors but, I tell you, as reported just above, changing the transformer is even more transformative! Old stock tubes are expensive and, unless one already has a stash (like I), to me it pays to start with the better transformers. Enthusiastically Recommended. In fact, it had me thinking about upgrading the transformers of my TU-8300 (this Lundahl is not suitable). Also, if I don't already have the TU-8300 and the 6V6 based TU-8150, I'd buy the TU-8800VK without hesitation. It is also time for me to do some surgery on the TU-8150 (bypassing the earphone and mini-jack input that I don't use) to bring its performance closer to the 6V6 in TU-8800 (though unfortunately there is no transformer upgrade).
Tube Rolling Given the versatility of the amp, tube rolling is a temptation most cannot resist. Yet I'd like to give some guidelines here. In general, I think, even with the most humble of tubes (the current stuff) one can get a good sound. Get your system right before you go crazy rolling tubes! There are priorities. No amount of tube rolling is going to save a system that is intrinsically unbalanced. But, when you get your system to sound right, tube rolling becomes the coveted final touch. In this article, because of my stash, I can indulge in some of the best, but this is just for reference as to how far one can take the amp to. Here, I'd like to remind you upgrading to the Lundahl transformers is more essential than spending a large sum of money rolling tubes.
12AT7 This is very critical, and your system and taste shall likely come into play. Experienced tube users know that the input/driver tube(s) have as much, if not more, effect as the power tubes. Unlike the many tube "gurus" out there I usually shy away from a recommendation, because I believe there is no best tube (aside from old-stock tubes are better than current ones), and context (a system approach) is just as important. That said, I do believe the old-stock GE D-getter 12AT7 (not that rare) is a very fine mate with this amp. A new pair is not that expensive and used and test good tubes much cheaper on Ebay.
High Power Output Tubes With higher B+, more inefficient loudspeakers can be driven adequately, as evidenced in my Part I Report with the 87 db LS 3/5A. But, even with my 97 db Heresy's, the higher power mode still performed admirably. Basically, I think the designer designed it using the KT88 as prototype. Even the Russian "Genalex" KT88 sounds pretty good (especially with the Lundahl's), and I'd wager the KT120/150 would too. I'd avoid the KT66. And the performance of the genuine old-stock GEC KT88 propelled the amp into another league altogether. But the genuine item is very expensive and off-putting to most people. The old-stock Tung-Sol 6550 is almost as good, but cheaper. Enough said.
Medium Power Output Tubes I'd think EL34 is worthwhile. If you already have a stash of EL34 or 6L6GC/WGB etc you would have some fun. I certainly have not tested the vast 6L6 family extensively, but for now I can recommend only 6L6G.
Low Power Output Tubes If your system allows the use of low powered tubes, greater power to you! For me, I just love the flea-powered 6V6. Old-stock 6V6's are very reasonably priced, but I know not many can use this kind of flea-power. But, if your loudspeakers are efficient, and your room is small, try it for not that much money! You will be surprised! For me, a horn user, it is my preference.
Power Mode Switch I'd like to implore you once again that it is imperative for you to check the position of the switch when you change power tubes.
Integrated Amp vs. Power Amp If you want to connect more than 2 sources and if you have to use a preamp, make sure it is one without gain (passive, TVC, or even Elekit's own TU-8500 in Unity Gain mode).
There! It took forever to write this article on a Windows XP！

Top, L to R: 6V6GT, VT107A, 5881, 6V6G, 6L6G;
Bottom: L to R: EL34, 6550, KT66, KT88




Elekit TU-8300 in action

Innards of the TU-8300

Same person.

I usually build Class AB, never built a Class A amp before.

My first build Class A amp, I think output is 15W pure Class A.
Each channel using two pairs NJW1302 / NJW3281 running 500mA idle current per transistor with +-22.5V supply voltage.

The heatsink size 30cm x 12cm base thickness is 5mm with 12 mm small fins.

Now my room temperture is around 27'C and the heatsink temperature will be 65'C, my finger can touch the heatsink but can not stay on the it more than 2 second.

I want to know for a 15W output Class A amp, how high a temperature the transistor will be in danger. Summer is coming, at that time the heatsink temperature must be very high, I want to know the safety temperature range to run the amp in Summer.

Best regards,
Patrick

Hi all!
I'm new here. This forum looks great 🙂 I hope I'll find my answears here.


I'm going to build my first audio DIY project: a szekeres amp


First: I choose the szekeres because of it's simple design, and I've heard it sounds good. I'll use it for a Sennheiser HD565 on a computer (with sblive).
Is this a good choice? Or do better amps exist (better and not really more complicated) ?



Do you have some advices on the szekers model that sound the best? (DC coupled; CCS...)
My first choice is to build the latest one that is on headwise's site: (if nobody tells me it's a poor choice)

http://headwize2.powerpill.org/projects/showproj.php?file=szeke1_prj.htm




Now, I'm working on the PS. I've heard the szekeres are very sensible to ps quality, anr ripples. So I'm going to buils th PS myself, and not buy a regulated PS (a friend gave me a torroid transformer 2 days ago, so I haven't to buy the main part)

I'm thinking about using this model:



It's a ZenV4 PS. IMHO the design is good. But the values (especially for the condensers) are to be changed.

The problem is: how much will be good?

The transformer is a 230V (primary) 12V (secondary) 50VA. Will it be enough to drive a stereo szekeres?

What do you think about all this?
Can you give me some good values for the condensers?



Thanks a lot 🙂

There are 56 in the box. $35 shipped 48 states for all of them in the box shown.

These are new old stock as when I got them a few years ago. They must have been really dirty as it looks like someone cleaned them and took the numbers right off!

5 volt filament for two triodes, one section is a 12AX7 and the other is a 12AU7

Hi. My friends have an old musical fidelity B1 integrated amp - currently only used to listen to CDs. I want to buy them a new Rega Planar 1, but I’m concerned about whether these two would be compatible due to the age difference? It’s a surprise present & (also due to current social distancing rules) I can’t see a way of finding out what connections are on offer with the MF. The Rega states that the amp must have phono MM. So, basically, can someone tell me if it’s possible to plug a new Planar 1 into an old Musical Fidelity B1 and for them to work? 😕
PS please don’t go all technical on me - I have only a very basic understanding of all things electrical. Cheers

Hi guys, absolutely newbie here. I'm looking for a single channeled single ended preferably solid state headphone amp kit. Beginner friendly ofc. Does anyone have any suggestions? Thanks!

Has anyone yet nailed down a source for the CPF2377 Noritake FL display tube? I've got a client's Caspian with one that cracked & lost vacuum. Anyone determined what Sanyo model players or other cheaper players used the same display?

I used brutal force to open STK082G hybrid module from old DUAL amp. Most people, including me, presume that defunct module is due to fail output transistors but it seems to me that output transistors are OK, nothing seems fried. But there is one SMD component, I am not sure if it's resistor or cap, that seems like the color of body is spilled around the component.

I am so sorry to see such advanced component to be discarded just because SMD component failed, if that's the reason. After all discrete components could easily be serviced, but if you have to throw away complete power amplifier just because one SMD component... Hybrid modules looked like such smart idea...And they sound very good too...

I have a couple of original Sumo Polaris amps which are over 30 years old. I would like some suggestions on what capacitors I should and shouldn't change. I just replaced all the capacitors in a Sumo Athena. I also purchased identical spec power supply capacitors for the Polaris (Nichicon Super Through). However, some of the capacitors for the amp's PCB I can not find replacements with identical specs. For example the C9 (Culver, 16 uF - 50vdc - NP). Would it be alright to go higher in capacitance on that capacitor? My guess is it would not be ideal. I would also like suggestions on brand and types of replacements. I don't mind doing slight modifications either if it will result in better sonics and open to all suggestions. I am looking for the best possible replacements. I care about the amplifier as its been in my family for a long time. Thank you!

Hi all,

Anyone know about this Cap? What brand and what type? Like PIO or something? Where can i buy it?

Thanks

In a situation where your speakers would have a peak limiter set higher than the maximum peak output voltage of their connected amplifier would it be better to set a zero attack limiter with a short release time (4mS) just below the clip limit of the amplifier or to let the amplifier clip? if so how far below the maximum output voltage of the amplifier would you set the limiter?

Anyone use the SEAS kit here and did this build? I wonder how close it gets to Joseph perspective 2.


Seas Delling Excel Kit Pair

I am planning to install two 100 mA panel meters in the SE I’m building. I read somewhere on this forum that I can put the meters in place of R18 and R29.

Can someone confirm that?

Thanks, Jacques

I downloaded PSUD today, but when I click on "Help" I get the following error message:

Help Viewer Error
Browser "shell:AppsFolder\Microsoft.MicrosoftEdge_8wekyb3d8bbwe!MicrosoftEdge" not found

Any ideas on how to resolve this?

Hi Guys.

Im a real rooky with Amps, I really love electronics and love amps and music gear, recently finished a technician electronics so I know some of it, but want to learn the real deal and since I like Amps I think I will go for investigating and creating a few ones, I just recently finished a TDA2050 amp which works fine but not satisfied yet.

Thanks and looking forward to learning together.

Hi, I found this forum during my quest for information on subwoofer design, so now Im here to pick the brains of you guys with knowledge that would no doubt bamboozle me completely!

I can't find service manual and need to know What trans are in D1 and D2

Dear Sir,
I own a cd player CD SYMPHONIC LINE 4018-Reference Mark II , with the nickel front panel, unfortunately I lost the remote control when i move to other house.
Can get help please,
there is a remote control that will operate with this cd player, can someone copy it to a learning remote control, any help is very much appreciated.
Best regards,
Williams

Has anyone else had issues with the trident regulators dropping voltage after prolonged use? This mainly happens with my 1.2v regulator. I have check my Placid HD power supply and it is sourcing plenty of current.

LTspice model of amp.


View attachment k4040.zip

First of all I do not know if this thread belongs here, so if there's a moderators that thinks it should be moved somewhere else, just do it and let me know.

I have researching this matter for a long time: how to assemble a 5.1 or 7.1 preamp to be used in a high quality home video setup.

It must accept at least one or more HDMI inputs, and offer some way to select them, if there's more than one.

The output should be analog, with RCA sockets, to feed a multichannel amp or amps, and some way to control output level, passive or active.

It may also accept other sources, like stereo channel ones or DSD, with the proper interfaces.

It seems I may have found a company that makes several digital boards, and the most promising board seems to be this one:

ST6000 DAC ES9023x4 HDMI 24Bit / 192kHz 7.1CH for Raspberry Pi - Audiophonics

Apparently you input your HDMI signal, and it extracts and converts it to 7.1 analog audio.

The analog interface has 1/8" sockets, as PC motherboards now have. But I guess you can solder proper RCA sockets to each output.

Perhaps there are other similar systems that I do not know about. But I would like to have opinions, ideas, etc. on this preamp I want to assemble.

I have already asked Audiophonics for more info on this and other of their boards.

Hi all.
I hope everyone is safe and sound, staying healthy.
So I have a AP1200 that is doing something a kinda weird, from a cold start it will play for 15 mins or so, then go into protect, and then out of protect, and then do that over and over a few times, but as soon as it warms up, say 30-40 mins, stays out of protect and works just fine.
Seeing as with the current state of the world, most shops are closed, so I was going to attempt at little troubleshooting on my own.
I am NOT a skilled electronics guy, but am a licensed mechanic by trade, so I can do mechanical repairs, visible wiring repairs and the like.
I do know how to use a multi meter safely and correctly.
I already have one AP1200, and I changed the fan in that one, no big deal.
Seeing as the Protect on this amp is mostly to protect against sort circuit from speaker load only, I am kinda confused. I am 100 percent positive the there is no shorts from binding posts forward, and I had the cover off the amp, and it is a short distance from binding post to board, so not shorted there for sure.
Cold solder joint?
I can supply the wiring schematic if needed, and I have the service manual.
Any ideas?
I know its kinda a tough one without having the amp at hand.
Thanks and stay safe!
Dave.

Powers up no sound. Metered all trans to be good even changed driver board. Still no sound. Any ideas?

Hello all:

I have a few MCM 55-1205's* kicking around and want to experiment a bit. Some are currently in .3 cu ft sealed boxes which actually sound better than they should. I want to see if they are candidates for TL duty. The first kicker is I want to use a 2.5 TMM configuration in leiu of BSC, rolling the second one off around 600~ Hz instead of burning 3-6 dB up in a resistor.


Second is I want to see if it is practical to use a tall/ slim straight / folded TL to get what low end there is.

I also found out I'm a few days late to get Martin King's mathcad files, so I am trying to bend my non-calculus brain around the still available charts. I also found a couple of calculators to try modeling some configurations instead of trial & error. Paper is cheaper than sawdust.


What I have been exploring are iterations on the Weems Pipe, but with updated math for the TLL with the SL>SO. One spreadsheet wants something like a BIB line, the other looks more reasonable but I'll have to translate some German terms... Looking for some more (non-calculus) solutions, or a line on the currently unavailable MJK mathcad files.



Thanks in advance for your feedback, pointers, and suggestions .


* Here is the driver sheet: www.newark.com/mcm-audio-select/55-1205/5-1-4-poly-treated-cone-woofer/dp/36C6658
Fs=65Hz, Qts~.77, Vas=.388ft2.

Hello everyone,

I am considering using a smps for a guitar preamp.

I never did it before I usually use a linear power supply in all my builds.

My question is:

If I feed the smps 12vdc from a laptop power supply I have no ground wire coming in.

How do I ground the whole thing and keep it safe?

Thank you

Glass painter

Hey Perry,

I just finished building a 500m back from the grave. The amp working almost perfect except the amp will not shut off with remote power removed. Have you seen this issue before I swap out the lm339?

I've built myself an outdoor BT speaker but the signal is pretty poor as the BT unit is buried in the thick walled wooden enclosure. I have to have my phone within a couple of metres.

Is this the aerial..the wiggly copper trace? And can I just solder the central core of a coax cable to this and add an external wifi type antenna?

Anyone have a set of Woodgrain Walnut base for 1+1 laying around? I have a set of black bases that I can trade too...

Need to match the original matching Acoustat Sub

Looking for schematic or at least the value of R1 for the power led , mine is burned up surface mount resistor , led has 28vdc on other leg

Hi Everyone,

Im changing my conventional wired Ncore Amp to one of the kits provided by Ghent Audio but I am confused!

Question 1 - Which how I wire the Neutrik NL4? For each amp I obviously have 2 cables coming from the module to the case, but I have 1+, 1-, 2+ and 2-. Photo attached. How do I wire it?

Question 2 - Powercon only has 3 contact points unlike a normal IEC inlet. It has L, N and earth only. How should this be wired? I have two wires coming from the module, one read wire, one black wire.

Question 3 - Does the solderless XLR work in the same way as the conventional one? I can see on the solder less one that it has helpful numbers 1,2 and 3.

Turns out I'm still a complete bonehead.

I lost my +12 battery connection while I was bench testing and now the amp doesn't turn on, power LED glows very dimly.

My guess is I popped something in the turn-on circuit. Does anyone have a schematic for this amp or one similar? (PS gate drive is a volt-ish DC, should have checked the reading before tearing it down)

Live and learn, that's why I'm working on these cheap amps.

Thanks in advance gents. Worst case scenario I just buy the service manual for a one-off repair.

For sale are Bud's Purvine used 5k SE trans for 45/300B amps. He never specified the current but said up to 80 mA is "doable". I only ran it in 45 amp so around 40 mA. Was going to make a Reichert amp with them but nah... $245
Push Pull interstages were supposedly built for Lynn Olson ballanced amps. . two primaries , two secondaries and suitable for variety of tubes . No DC on primary. never used. $200. Pictures later

Hi guys are you aware of the best schools of speaker design, crossover design , speaker electronics etc ... in Denmark or Europe please ?

i found a blown resistor on the "crossover filter" of my "Power Dynamics Galax 10S Studio Monitor Subwoofer" and i found this on the "crossover filter" board "SUB100C 026147581 VER3" but there is no schematic! :/

The resistor was so blown and damaged i couldn't see the color code nor test it!

Quick question....

Will a capacitance multiplier work as a ripple filter....I am trying to measure millivolt range voltages so was wondering if a capacitance multiplier would work ?

Here is the circuit - SIMPLE_RIPPLE_SUPPRESSOR - Basic_Circuit - Circuit Diagram - SeekIC.com

Hi

I have a little active sub that one day decided to quit. The specifics I'm unsure of as I weren't there. But from what I was told it either happened when the sub was being turned on or when the line sub in was connected. There was a really loud pop, and it didn't work after that. If playing it now there is a very faint sign of it working, but I think it's being powered by the signal power itself, meaning the amplifier circuit doesn't amplify... The boards has a relatively simple layout, no surface mount components. I looked carefully over everything, but nothing seems to have failed, the fuses are also intact. I haven't managed to find schematics for it either. Does anyone have any idea of what could be wrong?



Thanks,
MrGecco

Several years ago, probably 4-5 I bought a Chipamp 3886 kit.

I assembled the individual pieces and the idea kind of faded away.

Decided to pick up the hobby again and force myself to make the time for a hobby once again.

So I pulled out the box I stored the stuff in. I've assembled the individual parts and I have a Lindberg Y236750 Transformer.

The original manuals do not seem to be on the website anymore and I have the V.1 boards.

How much can this push out wattage wise? For an initial project I'm looking to put together the amp and build a small set of speakers for my wife's office.

Are there assembly directions anywhere?

What would be a good pairing of inexpensive DIY speakers to pair with it? She'll be plugging it into her iMac. Maybe want to spend $150-$200 on the pair.

Thanks

Firstly, I apologize as you would get these types of threads on a daily basis, I did do some searching but was unable to find any non Dayton/TB suggestions.

I would like to make a pair of speakers in the 0.2-0.3cu ft range and would like to be able to have an f3 in the high to mid forties.

It will be active two way with only 40W RMS at 4Ohms, I don't expect it to go stupidly loud as drivers able to play that low are usually quite inefficient.

They will only have to play up to around 1.5k and will be crossed with a 3rd order crossover.

Budget would be tops of 5-6 hundred USD for a pair of drivers, I would like to avoid Chinese made stuff if I can, like to share the wealth.
Sadly I missed the Purifi drivers in the FS section by a day, at the moment the Fostex FW168HR is at the front of the pack with the Seas Prestige Titan L16RNX3 coming in second, if Seas did a 4Ohm version I'd buy it.

Thanks for any assistance,

Hi 🙂

First post 🙂 I have started to plan my first "real" speaker build. With "real" I mean actually doing some calculations and not just put an old recycled woofer in a cabinent with some guessed measurements.

Since current living condition is limiting the space a bit, the plan is a pair of slim wall speakers for a rather small room. Volym about 3-4 L (or 0,10-0,15 ft3) with dimensions around 55x17x8 cm (or 22x7x3 inches).

My main question:

I have read up on crossovers and played around in Xsim a bit. Started to find something quite good, but then I learned about baffle step. And to me it seems like if I'm going to design my own crossover, I might as well include a BSC. But then I also read about bass support from walls when speakers is situationed close to wall. How do I simulate these two things at the same time?? Haven't find a good guide on this, but I'm thinking it must have been done before?

I don't have equipment to measure and I want to order both drivers and components at the same time. I know that I otherwise could have build the cabinent, measured in place, and then designed the crossover... but this is going to be a design made in theory...

Second question:

I have focused in on the Dayton Audio TCP115 to use as woofer, and pair it with a bit more expensive tweeter that can be crossed over relatively low (approx. 2k). The reason being that this woofer simulates well in small cabinets, and is supposed to be able to play down to 55 Hz in my preliminary design. But does it sound good? After all, it's very cheep... I probably going to build subwoofer next, so maybe it's unneccessary to aim so low? Better to maybe aim at say 65-75 Hz, and have higher sound quality?

Suggestion on drivers?

As info, speakers will be powered from a Rotel RA-03.

(I have also played around with the idea of a small line array 🙂 But then I'm guessing both the high's and the low's will suffer.)

Thank you for answers!