Hi all,

I'm so glad I found this forum. Its hard to find communities these days that are filled with people who are passionate about their topic or hobby and successfully managed to keep out the spam and chaff.

I have had several different careers, but the relevant ones for here are my current ones. I am an electrician by day, and I run a design/fab furniture shop in my afternoons (I also have 2 young kids, so they get my nights).

I have several goals for joining up here, but I'd love to start out by building a nice setup for my workshop music. As always happens, I'm sure I'll dive in just deep enough to want to make different and more advanced stuff after I get my feet wet.

Just so I can point back to here in future threads, I have a 3'x3' spindle-powered CNC (and a 4'x8' soon, hopefully), a 3D printer, a decent grasp on Fusion 360, a full compliment of woodworking tools, and a nice little bench power/soldering station.

I look forward to picking your collective brain to get some cool things built and I hope to gain enough experience to be able to contribute my own advice in due time.

Found web site and want ask, have Realistic sta-2000D. Moved to paint now shuts down in 1 second. Is that a repair for me o audio shop? If shop where is audio shop you recommend? Live near SC. OR NC., And do not want any of those NTC or ECG parts. Thanks in advance for your help and having a web site to help people like me.

When I'm bored I sometimes use the local channels' weather radar to wander the globe. While checking out Australia I zoomed in on this city ... Kalgoorlie.

Now being from the midwest (USA) I've seen some deep holes (iron mines) but the one @Kalgoorlie looks pretty deep. Got to ask anybody that lives around there ... how deep is that?

I have a left over analog board suited for the TDAI-2170 and TDAI-3400 with a nice AK5294A ADC on it. I didn't find a service manual online but it seems fairly easy to run it stand alone: I managed to select the inputs and the +6dB gain by writing from an MCU to the 74HC595 which is accessible through the multi pin connector.

The board expects 3 power supplies of (I believe) +12, -12 and +5 volts, but there is one thing I don't understand:

The relays have 12V printed on them and are directly supplied from the input voltage, so I don't think I should feed higher than 12V to the board. But there are two regulators in series on the board: a 78M09G and a 78M05G, generating the 5V needed for the AK5394A. But the 78M09G has 10.4V at it's input and 8.7V at it's output and the data sheet says drop out is 2V (the 8.7V go into the 78M05G which outputs 5V). What do you think?

Please could anybody who has a Lyngdorf measure the voltages on the pins shown in attached picture for me? That would be of great help! (The attached picture shows the motherboard inside the Lyngdorf with the multi pin connector where the ADC module connects to.)

Been living in France since mid 2009.after leaving Spain after 8 years. The Spanish word 'enchufargo' explains all, it means to be connected, I wasn't and if you aren't nothing is possible, 80% of all €500 notes were to be found in Spain, mainly in brown paper bags. No matter how much research you do you can't trust notarios/alcaldes/bankos/abogados/immobiliarios you can still end up having your house bulldozed and being fined an awful lot of money - so we left.

Would have bought land and built my own design house but health problems got in the way for the next 6 years. We will get our Residency papers soon removing any doubts about continuing to live in France.

I was all set on buying a plot of land with building consents but for some reason or other I happened to look at American motor homes and further 'fifth wheels and travel trailers'.

Why - there is land with building consents, around €30K and there are other plots of land which you can use for recreation - loisirs which is very cheap, €5-10K normally around 1000-1500 sq.m. There you can park a campervan etc. no problem but you cannot build a house.

I've read quite a bit on American sites about the good and bad points with motorhomes, fifth wheels and travel trailers. I've ruled out motor homes, so I'm only interested in fifth wheels and travel trailers.

Any Americans or Canadians with actual experience I would welcome real time info from.

A lot of problems can happen because of (a) being on the road and (b) from being left out in all weathers.

I would construct a reinforced concrete hard standing with a water proofing additive above the level of the ground and once sited would not be moved, that should take care of problems associated with being on the open road. I would also construct an insulated skirt to protect the underbody from corrosion. I believe that I can have a water supply connected as well and have a fosse septic. With a diesel generator that makes me pretty independent of Big Brother.

If I build a house then I have to pay the housing tax known as Tax foncier, this is creeping up with every year. Living in the either model avoids this tax and insurance is cheaper, much less chance of theft or damage with living full time in it.

Some well known names in the RV industry have a bad reputation and you can't trust user reviews supplied by the companies themselves because no way will a company publish stinking reviews of their companies products.

If anyone can direct me to good user forums I would be grateful.

Problems with buying American - 120V electrics and non existent servicing, though apparently this is a problem in the States as well.

Why buy American - 30ft + are hard to find in Europe and like so many other things Europe is far more expensive than the USA. There are many top of the range models with loads of features that are around $80-90K. Yes I know I would have to pay shipping and in France a TVA/sales tax of 20% but then I have a fully fitted home I can move into straight away. Very good insulation is another +. compared to an old French house where you swelter in the summer and freeze in the winter. New French houses are so noisy (construction materials) and they are obsessed with having tiled floors - no thank you.

The biggest negatives for me are the colour schemes of so many are very dark, not a good idea when living permanently in one and cookers are for me outdated when a quality multi-oven is so much better. A big shower is also a good idea. We don't need sleeping for 8, there are just the two of us and at our age we don't expect lots of visitors. a massive fridge is not a good idea rather a decent sized fridge and freezer.

So please direct me to good RV users forums and any other useful tips or suggestions - thank you

Hi guys!
Here I have the headphone amp schematic that came up with and I would like to get some tips from you or maybe even confirmation if you think that it should be a working circuit. As a preamp, I'm using 12AU7(ECC82) and as a output stage WCF with ECC88. It is meant to be able to drive 32 ohm headphones. The first half of the ECC82 acts as a volume control and then the signal goes to eq and then to the second half of ECC82. I really apreciate your help. Thanks.

Hello clever people,

I am looking at replacing some old caps in a vintage ARC preamp (still trying to loose a tiny residual hum) and thought I might see if the output caps coming from the cathode follower on the last valve might be part of the problem. This valve has an AC heater.

Anyway the question is related to the value of these. They are currently 10 uF and I have been told by a friend that if I have a high input impedance Power amplifier (which I do at 100K) then I could happily use 1 uF and they would probably sound better, and I could afford to fit in some more exotic caps too.

Is there a calculation that manages this relationship in any way? I found a website that calculated Impedance at frequency, based on capacitance; and obviously this changes at frequency, and also implies the lower value capacitor would seem to decrease the output at lower frequencies.

Any helpful knowledge here.

Circuit diagram attached.

Thanks!

Hi I currently own a Naksa 80 and I would like to know if it's worth it, to upgrade to the Saksa 85. What do you think?

Hello, I am looking for a pair of RS291.

They must mesure as new or very near .

Better from European Union for shipping .

Thank you in advance.

Hi,

Is there a way to use the analogue inputs on the DScope to record into an editing package such as Audicity / Reaper etc?

It's not been seeing a lot of use at the workshop, as we have other AAs from R+S, AP etc. I was thinking that were the DScope to work well as a soundcard, it could be useful to have in the home system - enabling one box to record, as well as run health checks on the home setup.

Thanks in advance.

Based on tracking pre-regulator circuit form National and this link I expect to achieve 1A regulated current. But in reality ripple voltage is around 0.2V RMS.
The voltage across second reg is around 2V and does not change if one or two red LEDs are connected between Vout2 and Vadj1.
Sims in LTspice are ok.

I'm making bookshelf speakers for a friend as a gift for letting me get married in his backyard. I owe him so much more but this is a start. We narrowed down his expectations and I'll try to distill them here. I've mostly made parts express kits and a few Paul Carmody designs so I'd love to branch out with this one. I tried searching around but I'm drowning in possibilities and need help finding an established design!

The end goal is for casual background music and occasional moderate-volume dance parties. They will be moved around in the future but for now, they will be in a somewhat poor location, near an entryway corner in a 20'x20' room a few inches from the wall. My friend was in audiophile circles in the '90s so has an ear for decent sound, but he appreciates a more "casual" approach now.

- 14"x8"x8" so ~13 liters with 1/2" baltic birch (+/- an inch but this fits well on a console table.)
- <$350.
- Self-powered.
- Aux in for a record player and Bluetooth capable.
- "stealthy" Mostly black and no bright colors or super flashy drivers.
- Protected tweeter preferred so I can convince him to ditch a mesh grill.
- Something that gets down to about 40hz, lower would be better.


I hope this narrows my options and would be grateful for any help!

Thank you!

I would like to own a good quality second hand CD player with optional USB and FLAC capability, on a budget.
regards
Prasi

Looking for ideas for a frame for grill cloth that is not too terrible in refraction. Old school frames were terrible, which led us to the generations of exposed drivers. My next build I need to protect them. At least the woofer as it will be next to a passage and right at elbow level. Being the woofer. A bit of welded wire hardware cloth may be OK. Ideas?

Parsing the Tubelab website and this forum, I see twinklings of a Tubelab Spud SE based on compactrons, dating back to 2008 and fizzling out around 2010 timeframe.

I also see a LOT of other activities in Tubelab's life/career as well as answering our various questions here in TubelabLand. With the Simple P-P taking up what looks like much time, certainly understand if the spud PCB is dormant. Heck, I can't even get around to building out my SSE board due to other commitments.

If Tubelab could look into their crystal ball, would a Tubelab SpudSE PCB be rekindled and available? A spud puffing out more than 3W/ch with a simple build and budget price tag would be suh-weet.

Danke

Hi, I would like to build a speaker similar to the Granada G2.

It is using 2 x AE-12 Dipole, a Scan Speak 12MU and 2 x D3004/662000. One in the front and one on the back.
The G2 is active, but I will prefer a passive filter.

Sensitive 2.83v
Dipole-12 8 ohm 91db, 4 ohm 94db
12MU 4 ohm, 90db
D3004/662000 4 ohm 91db

Can I mix 8 and 4 ohm’s drivers?

I am open for suggestions, just want a passiv filter

http://aespeakers.com/shop/dipole/dipole12/Acoustic Elegance Dipole12 woofer for Open Baffle Bass
https://www.scan-speak.dk/product/d3004-662000/D3004/662000 – Scan-Speak A/S
https://www.scan-speak.dk/datasheet/pdf/12mu-4731t00.pdfhttps://www.scan-speak.dk/datasheet/pdf/12mu-4731t00.pdf

I have a Rotel RDD-980 that occasionally won’t read the ToC on any random cd. It will display “err” after I close the tray. Now the funny thing is that if I open and close the tray 2 or 3 times it suddenly does read the ToC and plays the whole CD perfectly fine with no glitches or skipping.
I carefully cleaned the lens but that didn’t resolve the issue.
Does anyone with experience on CDM-9/65 transports have any idea what could be causing this ?
I’ve read somewhere that sometimes the disc platter tends to shift down over time on the disc motor spindle with these transports causing focus errors. I’ve been searching this forum for a couple of hours today to see if I could find some more information but haven’t been able to find a thread on this. Maybe I’m not using the right search term. Anyone able to help ?
Also, is there any way I can get an eye pattern from this player ? I have a scope but can’t find an RF test point on the circuit board. Nothing about this in the service manual either.

Hello Guys,

I am putting together a Audio Note 300B Kit 1 but not from the kit. I purchased the PCB's from Ebay and separately all the components.

I will use toroidal transformers from Toroidy - pls see pictures.

In my mech engineer mind I liked the symmetry and designed in CAD the amp to respect this for a pleasing visual experience, I want the amp like this.

But since I am no specialist on the magnetic interferences ....etc - I hand over to you for some help to avoid doing mistakes.

Attached is the current layout in CAD:

- chassis is 480 x 388 - ordered but not arrived yet
- green = outside of the chassis - left and right OPT and middle MAINS - all 3 are SUPREME version toroidals with stainless cover and filled with epoxy; mounted from inside with only 1 screw
- blue = inside the chassis - D88 is the choke tranny and D80 is a 2x12V tranny for my dual VU system - analog and tube
- all other blue rectangles are PCB's also inside the chassis
- red - holes in the chassis where tubes are protruding outside

Initially I tried also to place symmetrically also the rectifier tube 5U4G but changed my mind unless I place it in front of the driver PCB.

I am putting an amplified microphone output into a Zoom H4N recorder. Right now my mic board puts out (+/-) 2V differential into an ADC (I can adjust the feedback resistor) but I want to record the output on the Zoom.
I cannot get a clear answer on what voltage diff the TRS inputs on the Zoom expect, and, of course, the damage limits.
Anyone have this information?

Thanks
Fritz

I have a pair for Bohlender and Graebener RD75's and am looking for suggestions for woofers to pair with them. I would prefer open baffle but I am open to suggestions.

Hi Forum,
The following project is described in a different forum, less used by DIY audio fanatics.
(for the whole story with more detail look at Audiokarma.com

The last 9 months I have been working on what started as an Electro Voice Interface D revamp into a big project with a full range 5.1 set based on the Interface D design with 6 more speakers in the make to end up with a Dolby Atmos compatible 7.1.4 system.

It al; started when I ran into a nice set of two EV VMR and two EV ST350b speakers and suddenly images from my youth popped up. I have been an Electro Voice fan since my teens end 70's and have actually build a copy of the Sentry III in that time frame. The Interface D was lost in the dungeons of my brain ready to pop up after seeing the VMR.

I have the luck that my nephew has a great wood shop with CNC machines that was owned by his father (my uncle) and his father (my grandfather), so building speakers has been a passion for over 35 years and I have build many models in the HiFi and PA space.

I am not an absolute vintage geek, love those old designs but I don't need to actually recreate the original. I do want a good sonic reproduction of the design so I am looking for the original stuff.

What I want to change is the geometry of the enclosure. I want to give it a slightly more modern appearance but still remain truthful to the original design. This means that I want to make the unit the same height but a more shallow front panel but deeper. This will give a width of about 15" with a depth of 22" with the original height of 32". (this is actually the enclosure 90 degrees turned). I don't want the passive crossover in the open on the bezel, but keep that clean.

The advantage is a nice speaker to look at in the living room (higher WAF) with a better dispersion as there will be less interference from the front panel.
Volume will remain the same so the LF properties will remain unaltered. I need to find a 12" speaker that will be up to the task (thinking on a Sentry 500 driver).

In the early months of this project I mainly focused on the filter and an alternative for the woofer. Until after a few moths I ran into an original (Swiss made) Electro Voice Interface Delta. And through a business relation I got the original Interface D/Sentry VI design with all the mechanical details and filter schematic.
The project got boosted.

I found some extra information about the different VMR's?
There are 4 versions with a 2,5" voice coil, and there is the 2" VC VMR II used in the interface C, The Interface Gamma and the Interface 300 (the last one I had bought was a bad investment as one tweeter was defect one VMR was defect and the woofers were crap)

1803-9864 – This is the hi-fi version from the Sentry VI and Interface D

1803-9943 – This is the original pro version with a voice coil made from round wire. The repair manual says to rebuilt using the voice coil from the 18030595 below.

1803-0037 – This is the same pro version as the 18039943, except that the part number for the plastic ring was different. My suspicion is that this is the white ring stating VMR you see in some pro cabs.

1803-0595 – This is the later pro version with higher power handling with a voice coil made from rectangular wire. As near as I can tell, this coil has the same impedance and performance as the round wire coil from 18039943 and 18030037, except that it has higher power capability.

What this exactly means with respect to the sound is not clear. They are all quite similar but will most likely be different one way or another.

The Interface Delda's arrived:
The foam surround of the 12"down firing woofer was close to being powder. It has been refoamed and the units are playing again.
The enclosure is in an OK shape, but not good enough to be allowed in the living room (no, not my wife, myself)

The plan is to redo the filter by using all air inductors and high quality Mundorf polypropylene caps. This should make the unit sound better and if good enough I will rebuild the enclosure to a less wide but deeper and taller (same volume) shape bringing the tweeter in a better position.


.........Things are getting out of hand …. (that is not new for me ….)

The design of the Interface E is getting more and more shape.
The filter parts are ordered for a full rebuilt of the passive filter with all Mundorf high end caps and air conductors.

The STR350’s are all within a very decent range equal to each other. Very consistent behavior I have to conclude.

I also had some time to listen to the speakers. I used a fairly low cost 45W Denon integrated amp and a budget DVD player as a CD source. Anything but High End and just setup in the office where I performed the measurements as can be seen from the pictures in the attached PDF.

But wow …… the Interface is a very special speaker. I love it now it is rebuild and connected to a slightly better source and amp. The dynamics are awesome; the highs are clean and very honest. Voices are pure, and extremely honest as well. But the power and unlimited dynamics is what struck me most even with this modest amp. Up till now High End audio (and I had some really awesome speakers like the Avalon Eidolon) can be great transparent and with awesome soundstage but sound compressed and canned compared to the “D”. People on other forums raved about these speakers and they are all right.

Jumping to September 2014.
The 5.1 set is done, it performs very well..... see attached pictures

[/IMG]Does anyone have a set of Legacy Signature iii speakers they would be able to remove the front bass driver on and help me with hooking up the woofers correctly? I purchased a pair that were used with the three bass woofers being run in active mode so they are basically disconnected from the crossover. I was told the downfiring woofer acts as the dynamic brake for the bass system so there is some complexity to hooking everything back up. Any help would be great. Legacy is going to take a couple of days to get back to me so I figured I reach out here.

Hi All,

It is I, the novice of interesting mistakes. I am in the completion phase of my Nutube B! build. I have soured my own parts except for the transistors from the DIY audio store and built mu own chassis. I added a 3rd input to better fit my system. At power up, the nutube lights up on the left side, but does not on the left. All voltages check out except for T8 which has zero volts. T7 is at about 12.7 volts turned all the way down I know I may have damaged the R1 resistor closest to T8. Does that sound like my issue?

BTW, I have done a close exam of all of my solders unter magnification. The power section is as the build guide describes. There is no smoke escaping. I will attach a pic with my eyeball phone.

Any ideas welcome.

Thanks

I just snagged a pair of new Quicksilver single-ended transformers on E-pay. They look as though they were intended for use with the Quicksilver SET Mono amp,9W/channel, using a KT88 and 6H30 tube complement. Since the transformer impedance is 3.3k, I suspect that the KT88 was used in triode mode. Anyway, I have no intention of just trying to copy whatever Quicksilver did, but want to go my own way. I am open to some suggestions as food for thought, as it'll be a while before I get around to wrapping an amp around this iron. How would you use these?

I am starting late spring cleaning, and if I find something useful, but what I do not want, I will post it. Anybody can have it for free, just pay shipping. Most items will be small, so $10 will cover flat rate box to continental us.

Here is an example, two boards of AD convertors from Philips DCC deck. Working.

If interested, pm me.

Hello all,
looking for Fist one 1.4 or similar modules to buy, please offer ( in case or just modules are fine)

Thanks

D.

I restore old receivers from the 70's as a hobby to keep me busy in my retirement years. One question. I have a couple of receivers that the Stereo, mono, left, right switch has no effect. Appears to just stay on stereo no matter the switch position. My thinking it is the switch itself. Am I on the right track.

Were the 2.25 A @ 90V SOA (safe operating area) transistors like MJ15024-25 and MJL21193-4 available in the spring of 1994?

Please give recommendations for audio shop in N.C. and S.C., or web-site to send to for repair. Cuts off after 1-2 seconds, need someone will use oem parts. Thanks for your time.

Hi

I have an Audiolab 8000C pre- amp (older UK model) which has no output from the RH channel. It was fine a few months ago when I last used it and there were no pops bangs etc when I turned it on. The relay clicks as usual and LH channel is fine.

I have had a look at both sides of the board and could see no sign of shorts or components failing.

I note this one is fitted with an sds relais tq2-24v. Anyone know if these cause problems or aware of other common problems ?

Any help would be greatly appreciated

Ale M reviewed the ETracer on his website, EML 20-AM DHT curves and model – Bartola(R) Valves

The fellow who designed the Etracer, Chris Chang, has several videos on how it operates:

Video

Quick question for you guys. I was wondering if anyone knows if there are any DAC chips with the same (or similar) pinout / size as the Burr Brown PCM58P?

I've been looking around for a while now, but the chip seems old enough that most of the information has disappeared.

I'd like to replace this chip in a piece of equipment and perhaps get something more modern, perhaps up to 24/192.

Is this something anyone has done or am I being a dumbass?

Hi

someone can help me to find the manual of 118A?
I have a service manual but not the user.

Thanks

Walter

I am arm wrestling with a stubborn hiss (5mVac measured at speaker terminal). When the driver tube is removed, the hiss is eliminated. I have tried several grid stoppers (1K thru 330K) and none seem to have any effect.

I have tried shielding the tube without any success. Hiss.

I tried replacing the IT with a plate choke Cap/resistor coupling. Still, hiss.

Hiss is certainly coming from the Aa tube. And yes, I am aware that the Aa is not a good match with the 5K IT, but I am just trying to get the feel for the Aa.

Any thoughts?

The resistor came out of a Vandersteen 3A crossover (see attached pictures). I got the color code off it, but I don't know what value it is. It's bigger than the 3W resistors I have, but 2Mohm 5W resistor turns up no axial parts on Mouser, so I wondered if maybe I was barking up the wrong tree. I've posted on the Vandersteen forums, but if they don't come back with an answer, is there any way to figure out the appropriate value?

Hello all,

I'm looking for National Panasonic/Technics rotary selector knobs, the ones seen at the rightmost part of the amplifier...

This is a barn find, it was missing those two knobs and sincerely it doesn't look as good with different knobs ar all...

Who knows, maybe someone has this in a box of parts and would be willing to sell/exchange them

Thanks in advance!

Hi everyone! My first time posting here. I believe no one has ever posted about the difference between the stock output transformer of the TU-8900 and the Lundahl LL2785B, so I thought posting a thread about it could help someone in the market looking to get his first 300B amp and having a dilemma.

About a month ago, I was about to order the TU-8900 with Lundahls already from Victor and we've been exchanging emails about it. I know, most of you won't believe this, but the next day, a package arrived on my porch. It was a TU-8900! My wife just started her new job about two months ago and she asked me what do I want her to get me when she receives her first pay check. I said, a 300B would be nice! She wasn't kidding! I was so excited, but she didn't know about the Lundahl output transformers. And that's fine.

I proceeded and built the amp. It was my first Elekit, but I'm not new to diy stuff. It came with EH 300B tubes and Clear Top 12AU7s. Also ordered VCaps for it as well. I knew it requires a lot of time to burn in before I can really judge it, but I had to get the Cossor WE300B from Victor. They came in quick and replaced the EH. Right off the bat, the sound is more pleasing to me.

I gave it about 80 hours and I just couldn't stop thinking about the Lundahls. I emailed Victor and ordered the Lundahl LL2785B. Oh boy, it came so fast! He shipped it Monday and I received it Tuesday at 3:30 PM. Installed them and I was speechless, literally, on what I heard. The LL2785Bs are just next level in performance. And yes, I know it's too early to judge them still (I have only about 20 hours on them), but it's very good sounding. I'm not saying that the stock transformers are bad, especially if this is your first 300B amp (the case for me), but the Lundahls are more musical than the stock. Almost more of everything. The three biggest differences for me are wider soundstage, more 3D sounding (I can hear some instruments like they were coming from the back of my seat), more detailed, and the bass is so much better!

I will continue to burn them in as the Vcaps requires about 300-400 hours (based on what I've read) and I will post my impressions here later.

I believe that I need a LF transformer for my 1+1s, would prefer MK-121-C Red Medallion but am willing to use what I can get.

I've managed to blow (or break the flyout leads) of one so looking to replace. Scan-speak 18W-8546-01

Really annoying as they are in a wilmslow kit speaker with Scan 9300 tweeter and a load of Hovland crossover caps and after many crossover tweaks I really like them.



There's no Uk stock anywhere new and the only place I know that winds voicecoils in the UK has now stopped repairs and closed its doors.



Alternatievly does anybody repair/rebuild in UK/europe?

I have a pair of these that are used and I’m unlikely to ever build a 300B PSE now as I've gone down the path of big power hungry speakers. I’ve had them sat in a cupboard for 8 years since being bought used!
I don’t post much on hi-fi forums recently but have been a member here for years.

Datasheet here: - SE12 SINGLE ENDED OUTPUT TRANSFORMER 8

They’re BIG! Pint Glass for scale in pic. And Jolly heavy at 6.2KG each. I’m not sure about posting them TBH.

Current RRP is £737 delivered.

I’d like £350 + delivery or collection from UK surrey/hampshire border.


http://www.gt400.co.uk/wp-content/uploads/2021/04/Sowter-SE12S-300b-PSE6.jpg
http://www.gt400.co.uk/wp-content/uploads/2021/04/Sowter-SE12S-300b-PSE5.jpg
http://www.gt400.co.uk/wp-content/uploads/2021/04/Sowter-SE12S-300b-PSE4-rotated.jpg
http://www.gt400.co.uk/wp-content/uploads/2021/04/Sowter-SE12S-300b-PSE3-rotated.jpg
http://www.gt400.co.uk/wp-content/uploads/2021/04/Sowter-SE12S-300b-PSE2-rotated.jpg
http://www.gt400.co.uk/wp-content/uploads/2021/04/Sowter-SE12S-300b-PSE1-rotated.jpg

Hi,

I know its not exactly HiFi, but I am considering using a professional AV switcher as a way of increasing amplifier inputs.

In particular an Extron MPS112 - this will give me 12 additional inputs and the specs don't seem too awful (0.08%THD+N at 1kHz, 90dB S/N), compared to the cassette decks and 8-tracks that will be plugged in to it.

These are cheap on ebay and a lot cheaper than the diy solution I was planning.

It seems like a pretty good solution to me, but I haven't found much online about anyone using these for audio, which could be a bad sign.

Has anyone else used something like this? What was your experience?

Thanks, Jon

Anyone know idle power consumption of the various class D modules?

The only number I've seen is for this one

http://www.ebay.com/itm/2pcs-L20D-I...ltDomain_0&hash=item2c5dafb004#ht_7538wt_1258

"Total Idle Power Consumption 7W No input signal".

Doesn't sound like much but it adds up with 14 ch.

Question is, do they actually do anything useful aside from protect the dome.. In other words is it all a snake oil description for a dome cover. I have read in various places now that removing them can be beneficial..?

Hi All. I'm going to ship these in a USPS Priority mail flat rate box. This is all I have time for - therefore it's to the US only.

You can stumble upon these on Ebay (I see ONE now for $250!) or you can get them from Mouser (at least $500 each - hard to tell). Made in Andover MA.

These are 28V DC SMPS that have isolated outputs. You can run them in series for +/- 28v. They are trimmable to reduce output voltage if desired. Look to the Vicor website. You do lose efficiency when you trim them. I run a similar pair in an external chassis to my Pass M2 clone. The results please ME These Flatpacs seem to not mind capacitance on the output terminals, although you probably don't need much.

Pictured they are in series, with ~14ohm between the ~0v and +56v. They are doing ~4A with them in series. Another meter sits at ~28V at the output on one of them.

They are highly regulated and in my reading I gather that the switching frequency increases with load <this is from memory.

Of course these are not made for audio, but for industrial applications so really it's a chance, but if you've been looking to try them here you go.

Not sure what I paid for them, but let's go with $75 (from $120) shipped for them both. Paypal friends and family would be great.

Hi There!

I'm looking at making some desktop monitors for my office and have been considering one of these seemingly great full range plans: the .53 Karlsonator, the XKI and the folded TABAQ (have I missed any others??).

I'm getting a little lost though on which speaker I should be considering/choose. Part of me thinks I should try and find a driver that works in ALL of these designs and just give them all a go.

I'll be supporting whichever speaker I choose with a Wharfedale SW150 subwoofer for low end extension, so digging as deep as possible isn't really my goal. 60-70Hz f3 would be more than enough though if it doesn't affect mid/highs then going deeper isn't a problem either.

I'm hoping to only spend $150 USD or so on drivers as a maximum.
I'm in Australia so availability isn't a huge issue, but drivers can be pretty expensive here. For example Dayton PA130-8's are $40 USD each here. I'd probably prefer a 4" or 3" driver though for more high end extension. I might also be able to find an economical way to ship smaller drivers from overseas and get a lot more bang for my buck (stupid convict tax ~ it's an Aussie thing).

I'll be listening to these in the nearfield, maybe 80cm - 100cm away from my ears but 1.5m apart from each other. Max SPL is not a problem and I don't need to fill a large room. I will be placing them on my desk or on stands on my desk and they'll be about 15-20cm from a wall.

Bit of a comparison:

0.4x Karlsonator - Faital Pro 3FE25 Driver - 60Hz f3, 83dB SPL, 310mm H x 175mm D x 175mm W.
0.5x Karlsonator - Dayton PA130-8 Driver - 60Hz f3, 87-88dB SPL, 385mm H x 203.2mm D x 298.5mm W

XKi - W5-2143 - 60hz f3? - 91dB SPL - 320ish mm H x 274ish mm D x 223ish mm W (Apparently a very good driver).

3" Tabaq Folded - 65Hz f3 - 85 dB SPL - 272mm H x 226mm D x 144mm W

What I don't really have is a comparison of sound quality between the designs!
So if anyone has any ideas, driver selection advice, listening impressions or advice to chip in I'd love to hear it. If this thread turns into a great resource for desktop speakers I'd love to see that too. It's not a topic that seems to explicitly get a lot of attention and I feel these small full range designs, tuned for musicality and frequency response, rather than max SPL are perfect candidates for this use case.

Thanks everyone and I'd love to hear from you soon!

Hi all.
I wanted to pass on some trial results from playing around with a Scott 299B to see what is possible with the stock iron. I had done the usual mods to this type of integrated amp from the early 60s that is commonly advised: cap and pot replacements, etc, but was never very impressed with it sonically. This amp were clearly built to a price point and everything is pushed hard to minimize the parts count & cost. So I pulled out all the stops and changed almost everything except the output tube and iron.

I shoehorned a Hammond 159Q 7H/150ma choke in to run the PS as choke input. This got the B+ down to 310V nicely and allowed triode operation of the 7189s. I am running the 7189s at 35ma each as the power transformer is designed to supply ~140ma and I don't think they designed in much of any excess capacity. The stock fixed bias arrangement I kept as it works OK and I didn't want to lose 10-12V of B+ across a big bias resistor. No global feedback at this point.

The driver is a Schmidt cathode coupled type using a 12AX7. This is simple, works well enough and both channels only took an additional 4ma from the B+. All coupling caps, four per channel, are some old Tektronics 0.1uF/600V oilers I have been looking for a project for. Resistors are various wattages of Allen-Bradley carbon comps: nothing fancy.

I pulled the phono section out and all the various crazy filtration they used to put in pre-amps in those days. Volume pots are 100K Bornes. I replaced the tube sockets as well. So stripped to the minimum: 4 7189s, 2 12AX7s and a 5AR4.

This thing is really sweet and much better then I was expecting! For $120 of parts, its improvement has the best cost to performance gain of any mod I have done. If you are sitting on one of these 60s integrated amps(6BQ5, 7189, 7591, etc), the combination of triode strapping and choke input PS is very worthwhile IMO.

Cons? Sure, always are. Top and bottom frequency extension have been sacrificed a bit to get the super sweet midrange. And I don't know how long the PS choke is going to last running LC at 100%. Its started buzzing a good bit after only 50 hours, so it might not be up to this task. Oh yeah... and output power is down to the 5W range. I can get it to crunch on my 94dB speakers at a moderately loud level but it is not as harsh as the clipping was when it was running in pentode. Still very enjoyable to listen to within its power capabilities.

Thats it. Happy soldering!

First of all, this is a project that is _way_ outside my skills, so I have a good dose of blissful ignorance. But sometimes that helps?

Behringer makes a P16 personal monitor system that uses 2 sets of 8 channel AES3-based digital audio over ethernet cable. They have a very capable and physical interface to create a personal mix of the audio. However, I have a couple of wishes:
1. I don't need 16 buttons and a variety of knobs; I want to have it controlled through a touchscreen wirelessly.

2. I want a smaller package.

3. I want it cheaper 😀.

It occurred to me that it _might_ be technically feasible to even use an ESP32 to read in AES 'frames' into a set of DMA FIFO buffers, do matrix operations from the software fader settings, and then pass the audio out through an I2S interface to a headphone.

Because this is for personal monitoring, latency is critical.
At this point, I legitimately don't know if the optimized ESP-DSP libraries are going to be able to keep up with 16 channels of 48khz audio being mixed down to a stereo stream.

Does anyone have any advice? Is there an easier way to do this?

I'm looking to convert an old bass reflex speaker to an infinite baffle box. The simplest way is for me to affix a new front baffle to it but if possible I'd like to be able to remove the new baffle. Would a screw on panel be sufficiently air tight? Could I use a gasket or similar to achieve air tight status? Thanks

Hello All,

I've come into possession of a Melos MA-333, which has a LDR potentiometer (from what I gather these sounded nice but had a ton of reliability issues).

Whomever had this before me took the audio signal from the LDR board and piped it through the Alps pot below the board which was originally used to adjust current to the LDRs and adjust the respective volume (pot was no originally in the audio path).

I've no intention of repairing the board as several PCB traces were cut and it's a bit of a mess. The Alps pot in there now is a 100k motorized Blue Velvet - been trying to find information on how to tear out this board and just replace the potentiometer with a better one (say a TKD for example). I can't quite seem to piece all the information together as some forum members are saying there are some resistor changes I'd have to make in order to switch the board out and run straight to potentiometer (impedance matching?) - doesn't look this was done in the current implementation. The balance pot is also very strange, moving it to either position gives me a distorted left or right channel, not sure what is happening here.

Here's a video of someone who's gone through a restoration of the original volume board and may help provide some guidance to those who's knowledge eclipses mine. It's tough as there are no public schematics for this preamp (or any other of their products). Happy to provide pictures if anyone would like.

Hopefully someone is able to shed some light on what's required to make this happen as the group here has been immeasurably helpful in all of my posts, can't thank everyone enough!

Does anyone have a real BC330 transistor datasheet? Apparently it's a 1970's transistor from Texas Instruments, but it could be that Telefunken also made them, as they are often found in Telefunken equipment.

I'm looking for a datasheet that has some measured data on noise performance - I know it's supposed to be a low noise transistor, but not how low. I have found lists with a few absolute maximum ratings, the h_FE range, sometimes an f_T or c_cb value and the remark that it's meant for low-noise audio stages on the Internet, but I haven't found anything that looks like a real datasheet.

Thanks in advance,
Marcel

I recently found my first esl's, Acoustat 1+1's, and it turns out one of the large low frequency transformers has been arcing for some time and has a burned spot on the windings. I tried using several layers of Corona Dope on it, to no avail. I guess my question is, does anyone know if there is a person who rewinds these if you send them the core? Or does anyone know how to go about getting a replacement? The other speaker sounds amazing and I'd love to get these going, together. Thanks for any leads in this direction

I have friend with a Carver M-500t which puts out what sounds like a dimmer buzz at idle.

After reading the Carver postings here, I've come to the conclusion that it's probably noise from the triac in the Magnetic Field PSU. This can apparently misfire under light load conditions.

Does this cause a buzz at the outputs?

Does anyone know how to fix this?

Hi folks.
Though I'm more into SE Tube amps, I have had lots of fun with the Gainclone, and since there seem fun to have with Class D as well, I thought that 50 bucks for this tiny amp (on Ebay) wasn't much.

It arrived today. Usually I use my 300B amp with Tannoy, but since I'm reworking it and as well building another tube amp, lately I just plugged an olf flea market Kenwood antique on a pair of .. flea market Klipsch KG4. Very pleasant. But back to the flea sized Indeed TA2021. Something is just .. "not right" All of a sudden, I'm in front of a 2 way set of speakers. Bass is articulated, but the treble seem uneven. Some shouting around 10khz I'd guess.

Is this amp supposed to mellow a bit with time?

Hi, im looking for 1 x ada4610-2arz-r7 to complete my Autoranger however it seems to be out of stock for the best part of a year! Does anyone have one they can part with?

Thanks

WTB (2) 4.7uF Jantzen Audio Superior Z-Cap or Audyn Cap PLUS 4.7uF

Looking to buy two (2) 4.7uF Jantzen Audio Superior Z-Cap's Or (2) Audyn Cap PLUS 4.7uF for a crossover mod I'm currently doing. Please send info and price with a PM directly

Also Jantzen 15.00 Ohm-10 Watt Superes Resistor, need (4) of them.

Located: US, CA

Thanks

Hi guys.
I have a CAD M179 condenser mic and I cannot figure out how to get the damn capsule out of the chassis. I guess it is glued in there.
Any ideas?

Thanks in advance.

Hi

For Sale: 1x Sound Master TA-377A Full Complementary symmetry FET stereo preamplifier kit, utilizing matched pair transistors on RIAA and line amp stages. Has transistor-based regulation on board. No power transformer.

Included: Main PCB with all components stuffed by factory, full instructions, two excellent Alps Black Beauty 100K pots (one for volume, one for balance), selector switch and wiring.

The Kit includes everything you will need to make a high quality pre amp, except a 2x 30v Transformer.

Price £35 plus postage.

Payment by paypal please.

I am struggling to attach photos for some reason (I have managed it before), but I will try and add some, otherwise PM me and I can send some direct.

Hi Everyone.

I have found this forum while looking for suitable speakers for my TV. I have been using an old Altec Lansing CS21 system and it sounded really good. Unfortunatly it as died, and the tv sound is pretty horrible in comparison. I used it for concerts on youtube ,spotify and netflix.
I do have some space restrictions,and while looking for speakers I came across the Fostex DYI kits. Not only they would fit in dimentions ,as i could finnish them to match the rest of the house (WAF is an issue..).
That being said,i have no way to demo them before buying ,and i am a bit afraid that they will sound worst than the Altec Lansing system .
I was thinking in one of this kits:

Fullrange loudspeaker kit Fostex FF85WK, with cabinet kit plywood 18 mm thick

Fullrange loudspeaker kit Fostex FF105WK, with cabinet kit plywood 18 mm thick

Do you guys think one of theese would suit my needs?

In my computer I use a single Ikea Eneby20 speaker and i am totally ok with the sound ,so i'm not super picky.

Thanks in advance for your atention,and congrats on a very nice forum.Really made me wanna get into this hobby!

Anyone interested in two pairs of these drivers? I have a pair of the ET-5 and a pair of the ET-5A monopole version of the Linaeum tweeter.

I picked them up a few months ago intending to use them for a DIY speaker project. I've never gotten around to that project and probably never will, so I figured someone else might be interested in these tweeters.

Hello Guys,

I have an odd one, 6080 OTL amplifier, I plugged in a new preamp and it blew all of the tubes (they exploded) on both channels.

So, changed the coupling caps, same thing, tested the cathode resistor, perfect on the money.

Checked all caps for leakage on the LCR, not an issue could be found.

Checked the loading resistors on the speakers, checked out...

B+ is as it should b, -75 rail is on the money bias, I just do not know.

I have NO schematic nor values, but I have the spec sheets for the tubes (EEC82 Driver 6080 Output), I know that too much current is passing to the K1 K2 but I cannot work out how...

I say this as I dissected one of the tubes and the connection from the K to Pin has gone.

Also, I put in a 6080, turned it off then on then off then on and bang... same again.

Any help would be great, I am scratching my hair away.

Björn

When adjusting focus balance, looking at the diamond pattern, I've read many places here, that it should be both large and clear.
So, is that done on the same trimmer?

And is focus balance the same is E-F balance? If not, how does one adjust E-F balance on a teac vrds-10?

Kind regards,
Jacques

Hi!

I got a little Sansui TU-555 tuner. When I first got it reception was very weak and no stereo. A lot of caps were bad so I started by changing them, touching up the soldering and replacing the famous 2sc458 transistors. The result was slightly better reception. I than cleaned the local/dist switch on the back and now reception is great only it doesn't decode stereo : I checked and double checked the orientation of the caps I changed, tested the 4 transistors on the multiplex circuit that are fine, changed the trimmer resistor, cleaned the remaining switches but there's no improvement. When I turn the trimmer resistor clockwise all the way I have a faint glow from the stereo bulb when tuning to stereo stations but when I listen to it it's clearly still mono...

I get that this site is dominated by engineer types who seek perfection but sometimes the goal is improvement as opposed to perfection. What with a limited budget and available components.

My first argument was that, for the money, commercial manufacturers can build better cabinets than diy'rs.. So I purchased a JVC home theatre 19 litre sub for $7. My initial plan was to replace the 6.5-inch driver with an 8-inch driver obtained from a Tannoy sub with a dead plate amp (cost $15). However, I sold the spike feet on the Tannoy for $10 and the driver for $25 because the location of the port on the JVC would make fitting an 8-inch driver tricky.

The 150w JVC sub sounds nice, smooth and sweet but the problem was always going to be: SPL 77db / 30Hz / 6 ohms. After a debate with Chris661 and Weltersys they intimated that substantial increases in SPL could be obtained by an increase in diaphragm area.

Using only the components I have lying around this is the upgrade:

Don't you think this is a fun waste of $7?

Is Burr Brown OPA627AP the best way to go? are there better OPAMPs for the 405 to use?

Sorry for asking, but I have no formal math on this kind of circuit and it escapes me.

What's the input impedance of this tone network with the short vs without it?

Meter says 5k while shorted...

Beyond that, I could learn but I'd need "handholding" in this case.

Thanks as always 🙂

BTW I think I like the curves better with replacing all the 3's with 2's in the cap value.
Koda

Hi,

I have a 15" subwoofer I built, using 25mm plywood (you can see the cabinet with the green grille in the image of my vintage system!) and I use this subwoofer amp BSBPV500

(they used to manufacture for REL in the early days I believe and they seem to know what they are doing ...a lot more than me!)

My brother with 3 Sonus Faber subwoofers like the sound of mine and tried the BK amp direct into the sonus subs bypassing the SF amp, and he and ended up with 3 replacing the integral amp with the BK. He uses digital signal processing to align his which I tried and did not get on with.

I made a 12" version of my 15" sub with the same brand of driver for a friend who borrowed my 15 and loved it, but his room could not put up with the cabinet size..

Anyway the preamble set's the scene for the question. When I make my subs I use a CNC shop on a full sheet of 25mm ply, and with the 12" I was able to get two cabinets out........so I have the chance to try a 2nd sub.

BUT I would rather not also invest in a 2nd amplifier if possible (which would give me independent phase control of each sub with the integral control on the amp). So is there any clever way to create a phase adjustment for the 2nd sub with a passive controller?

Thanks,

Hi, I’m trying to repair a Vitus RI-100 integrated amplifier. This amplifier has socketed input modules, one per channel, please see picture. One channel has high DC on the output. It starts low, when initially powered on and then quickly rises to over 1V DC as it warms up. If I swap these modules between channels, DC problem also swaps. So I have it narrowed down to the module.

The amplifier works and produces sound, but I’m assuming that one or more of the transistor is partially leaking DC. And over 1V DC is extremely high.

The little SMD transistors are labeled RS and TS. I cannot seem to find what these SMD codes correspond to as far as actual transistor part numbers.

Any help would be greatly appreciated.

1J(1Ж).., 2J(2Ж).., 4J(4Ж).., 6J (6Ж).., 10J(10Ж).., 12J(12Ж).. tubes for sale

Sale:
1J17B for $1
1J18B for $1
1J24B for $1.5
1J29B for $1
1J37B for $1.5
2J27L for $1
2J27P for $2
4J1L for $1
6J1B-V for $0.5
6J1P for $1
6J2B for $1
6J2P for $0.5
6J3 for $1
6J3P for $0.5
6J4 for $0.5
6J4P for
6J5B-V for $0.5
6J5P for $1
6J7 for $2
6J8 for $1
6J9P for $0.5
6J9P-E for $1
6J10B-V for $0.5
6J10P for $0.5
6J11P-E for $1
6J20P for $1.5
6J21P for $2
6J22P for $1.5
6J32P for $4
6J43P-E for $1
6J49P-D for $2.5
6J49P-DR for $4
6J49P-DRU for $4.5
6J52P for $2
10J1L for $1.5
12J1L for $1.5

Hi Guys

Does anyone know the reference of the integrated of that driver card?

Im in the work of recapping a old vintage class a/b amplifier i own.
A Sonotron pa200 .
Sonotron as a brand existed only for a few years in the seventies until the production got moved and they changed the name to adyton. A name that are more known and are still known today .

while im waiting for parts i thought, why not make a schematic for it and make some posts along the way?
So said and done
My computer is not the latest model so not many drawing programs would not work, so i found digi-key's online schematic drawing program. So im learning to use it along the way too.
This project are mostly for fun, and maybe someone here have seen a similiar schematic. And maybe help me along the way . Who knows. Maybe modify it to sound better or do other things with it.

Im gonna post the llttle info i have collected over the years and updates of the progress 🙂

Hello FEMM and COMSOL experts out there.


Anyone here willing and able to do a basic sim about the properties/BL behaviour of the Purify 6.5 midwoofer's alternating 3/4 layer voicecoil?


According to Lars Risbo, designer of the Purify 6.5 Woofer:

the winding has 4 layers but with typically 2 to 4 gaps where the coil is effectively only 3 layers. These gaps flatten the Bl(x) by reducing Bl around the rest position. This trades some sensitivity for much better linearity (the reduced mass due to the gaps compensate to some degree). the positions and widths of the gaps are found using computer optimisation of a finite element model. I hope that explains it better.

I have MANY drivers and amplifiers. Time to upgrade and re-arrange. On the low end; I have the SB23MFCL45-4 single in a closed box just under 1 ft^3 powered by an older Hypex DS 2.0. I will eventually add a second one but will have to wire them in series for 8 Ohms. The Hypex does great with 4 Ohms but no way could it do 2 Ohms. This won't increase my overall sensitivity I realize but I will still have twice the surface area and I'm guessing I would increase the SPL's because the Amp will have an easier load. I never have to turn the main "gain" control up past the half-way point. With all bass EQ settings, in room response goes all the way down to 14 Hz! Remarkable for a single 9 inch sub. in a small, closed box! The Hypex has a non-defeatable 12 Hz high-pass (I think 4th order?). Moving on up from there...

Have you ever make tube socket adapter? If you have please share your ideas. Here I want to share the way I made it. The pins are pulled from wafer connector and square pin, one side is grounded round to ~1mm diameter (on press drill or hand drill). The ceramic tube socket has a small recess on top so a M3 nut can be fitted level to the socket. M3 screw hold the 2 sockets together tight spaced so the pins are 2mm apart. The square end of the pin tinned and then push into one of the socket receptor, and soldered. I wired it up for pentode strapped triode of a pentode triode tube, such as 6f12p so the tube pins are compatible with 12ax7, but G2 is wire directly to plate in adaptor so that pin 9 will be freed. It's a great way for comparing tube sonic without rebuilt another circuit.

12ax7 6f12p
1 3, 8
2 6
3 7
4 4
5 5
6 9
7 1
8 2
9 -

Hi.
Can someone help me with this IC.
Whst kind of IC is it?
IT is located at the input side om a subwoofer amplifier.

Think it says ST ZBGA439 but not sure.

Thanks for any help.

My latest and one of my favorite for looks unfortunately not very good for a mic.I left the mahogany veneer on the wood which looks good against the gold glass horn.Headphone element is used for the mic element.

Imgur: The magic of the Internet

I've got a bad fan in my 5800 and have ordered a new pair from Adcom parts, but they seem to have been delayed. So, need to find a temporary substitute locally. There's no identifying markings on the fans, so I have no idea what the CFM or rotational speed is. I have determined that the good fan will turn on at a voltage of 3.95. Has anyone else had to substitute a fan in this amp and what advice might you have? CompUSA locally has a fan of the right size, that will turn on at 4.6 VDC, so maybe that will suffice.

Hi all,getting ready to start another project a 2270, I am in the process of putting my BOM together and take a look at these main cap's the unit calls for 9000uf 55v these are not even close, what do you guys suggest to use??? This should be a challenging project!!!!

I'm referring to the heatsinks on Q3 and Q4 on the BA-3 front-end board: https://files.diyaudio.com/archive/gallery/data/500/IMG_04151.jpg

There are no mount points for a heatsink on the board. The heatsinks I selected don't sit flush on the board, and bend back and forth as I connect test probes and such. Can someone suggest a heatsink that will mount flush with the board, or otherwise make secure contact, so that it doesn't act as a hinge on the transistor legs?

Ventus is a mostly discrete opamp. 🙂

This is a circuit designed for some DIY fun. It is based on the Diamante circuit I published a while back.

The front end is a folded cascode design and runs into a LME49600 buffer. The buffer is in the feedback loop.

A schematic is worth a thousand words.

It sounds excellent. It can drive low impedance headphones exceptionally well.

As shown it is a BAL/SE converter and take balanced input from DACs such as Buffalo or Opus.

I would suggest when using it in this way (Balanced to SE) you use a relay to shunt output to GND on turn off to prevent any turn off thump. The thump buster works well in this role.

The Ventus can also easily be setup as a classic non-inverting amplifier with single ended input. It also can be setup as an in inverting amplifier with single ended input.

Each module is a mono channel so It takes two for stereo, and they stack easily.

There is a pot to null output offset.

We have boards tested and parts are en route so these will be available very soon.

The board is tested and proven, and I love it. I have been listening to it for a week now.

Take a look.

Cheers!
Russ