Hello, and thank you for accepting my request to be a part of this forum. I'm looking to learn about the interesting engineering that goes into creating speakers and audio technology. I'm hoping to at some point create my own speaker system, and i hope that this forum can be a big help!

Does anyone have knowledge and experience with EI e88CC made in Yugoslavia? Do you like it compared to Siemens or telefunken sound ?

In the mid 90s, I started to build PC based audio machines using WIndows and built in cards... then moved to Firewire... then moved to USB... but it always felt a little bit too much like a computer. (*)

I've been using Android tablets for quite a few years now as a streamer... with the USB OTG connection to a DAC. Running Tidal HiFi and FooBar... plays nicely. Usually I buy them at Costco when they go on sale for 200 bucks and I'll put in a 512FB sdCard into them. They do great for audio and are pretty good when I travel to get my email... ( hot spot my cell phone ).

But the hardware has a fatal flaw, IMHO, it only comes with a single USB port, so getting USB OTG and Power to work together at the same time is a crapshoot. Now, normally, a single charge should be good enough for ten hours or so of music, but it still bothers me. Also, sometimes I've ran into issues where the cable was borderline and the tablet would stop driving music to the DAC. Getting better cables seems to have solved the problem (knock on wood), and also newer tablets are more reliable (I'm running a one and a three year old -both Samsung).

So, I tried Raspbian with a Raspberry. It works great and it's actually more of DIY world, so it satisfies my needs nicely

BUT

It still a hassle, I wanted something that would not require me to make it look like it was a "computer" nor that ran into those pesky issues with USB OTG and power...

So, last May I got a Chromebook at Costco for 200 bucks... and I put a 1TB uSDCard in it. It has two USB-C connections and two USB-A ports as well... so I can charge it, use a remote mouse, connect via USB-OTG and the form factor is a little bit less obvious when I close the lid. I've also taken it to a couple of trips and It works quite well, having the keyboard makes it far easier to use for other tasks.... emailing is sure far easier than on a tablet/smart phone.

The Chromebook also runs dual ARM A7xx chips which makes them a bit better than even the latest Raspberry 5. Not up to par with the expensive Android tablets perhaps, but I don't run many applications.

The only downside with Chrome OS is that it wants my Google account password... I think I need to fix that when I get around to it.

I've been so happy, that I just bought another one today on the Black Friday sale.

I've been reading that it's quite easy to make them run as Linux machines (**)

So, for the time being, I'm moving to using Chrome OS as a music streamer, and will keep playing with Raspbian... but I don't know that I will play with the Android tablets much more.

What is your experience using these OS/platforms for music streaming?

(*) My home theater uses a Windows 10 laptop with an i7 to play DVDs and music. It can do Netflix, Foobar, VLC, etc... and it's hooked up via coax to a surround decoder AND via USB to an 8 channel DAC that drives the surround decoder via analog 7.1 as well. It works well but our latest smart TVs do Netflix and Plex so the laptop doesn't get the love it used to - unless I want to run the full 7.1 system. Hopefully my latest experiments with eARC will work, otherwise I might have to upgrade the surround decoder...

(**) I knew several people, developers, that for years have been buying Macbooks only to use them as Linux machines.

Does anyone have plans for a build similar to the Fern and Roby Raven utilising the SEAS FA22rcz 8" fullrange driver?

Looking to challenge myself and think these would be great fun to put together.

Any help would be very much appreciated.

I have a tube-based phono preamp with 787K resistors on the output RCA’s from signal to ground. I’m thinking of swapping out the RCA’s but I’ll probably end up butchering the resistors in the process; if I do, can I replace them with a 750K value? I’m sure I can, but maybe not.

https://www.theguardian.com/books/2022/nov/18/the-big-idea-why-does-music-have-such-a-hold-over-us

dave

This started as a curiosity for me in this thread on suitable replacement drivers for a small speaker similar to the LS5/3A. I decided to make a small sealed speaker of the same dimensions as the LS3/5A (12in tall x 7.5in wide x 6.5in deep) with a goal to reproduce the typical response that it so famous for - but using modest (inexpensive) and readily availble drivers. The Dayton RST28F-4 is a newer low cost but well built soft dome and the DC130A-8 is a coated paper 5.25in woofer that has a pretty smooth response.

Details on the construction of the speaker can be found here in the foamcore speaker thread. Basically 3/16in Elmer's brand foamcore sheets, doubled up on the baffle and braced. Noico mass loaded butyl damping applied om the inside aliong with melamine foam pads and grey eggcrate acoustic foam.

Here are some photos of the construction:






Here is the assembled speaker:


The measured raw responses of the drivers:


Here is first cut at the crossover (asymmetric Harsch-like with inverted tweeter):


Here is the XO implemented outside with Wago connectors:


Here are the Crossover Part Numbers from Parts Express (per speaker)

L4 = 5mH 18ga #275-141 qnty 1
L1 = 0.1mH 20ga #257-568 qnty 1
C2 = 4.7uF MKP #255-020 qnty 1
C3A = 10uF MKP #027-114 qnty 1
C3B = 1uF MKP #027-410 qnty 1
R2A, R4 = 12.5ohm #006-12.5 qnty 2
R2B = 1.0ohm #006-027-101 qnty 1

C3 = C3A+C3B
R2 = R2A+R2B

Here is the predicted frequency response:


For comparison, here is the measured response of a typical LS3/5A:


Here is the predicted impedance - very benign and nominally 7 to 8ohms with a 22ohm peak at box tuning:


Here is the measured frequency response of the XO - note the wiggle in summed values around the XO - results from the asymmetric slopes in a Harsch-like approach:


Edit 8/25/2020: I remeasured the freq response a few days later and applied 7cycle FDW to match closer the smoothing of the Stereophile data:


Here is the corresponding HD vs frequency at 0.5m and 2.0Vrms:


Here is the measured Step Response:


This is the measured system impedance with XO and inside the box:


Edit Oct 11, 2020 - Polar (horiz) frequency response measurements at 0.5m and 2.0Vrms:


I am just atartitng to listen to it.. nice sounding and very clear vocals. Will give update later once I have more time. But not a bad compact bookshelf using basic components.

3D CAD plans for 9mm BB ply version with beech battens and 12mm baffle to allow for rebates for flush front mounted drivers:




Edit Dev 5, 2020: wooden cabinets - called Rockville’s now finished and playing nicely. These speakers sound superb as near field monitors.


Crossover boards:


Back panel with name plate made (same as battens) from Civil War era white oak from a razed barn near Rockville Maryland.

Hi. I'm wondering if there's such a thing as a universal paralleling 'box' you can plug two identical mono amps into to lower impedance capability. G.A.S. aka James Bongiorno did produce a bridging box called "The Bridge" for bridging their amps which was a universal circuit. TIA

looking for some crossover design advice , will post thread soon

Howdy all,

I got an older console stereo system at a auction on a low bid. Its a smaller one. Has a turntable and a tuner. Would be nice to do some upgrades or perhaps just repairs.

Since this was basically free figured its a good place to learn, My electronics background is college level physics (just 100 level) and a little car audio, little RPi/Arduino. So when I look at the schematics on say the DIY chinese tube amp kits discussed here I recognise quite a bit of it.

Is there a good place to start to read about tube amplifiers and these old home stereo systems? I would like to be more up to speed than I am. Going to dig into the console next week see what is and isn't working. go from there! in the meantime need to update my circutry knowledge base.

Phil

Hi all,

I recently found some Lithium Titanate (LTO) batteries on ebay and thinking that they can be used for 5 VDC DAC or ADC supplies I'd just like to mention it here.

The batteries nominally are 2.9 AH/2.4 VDC (3 AH) versions, however, their discharge curve voltages start around 2.5 to 2.7 volts. See e.g. here (larger capacity battery):

lithium & solar power LiFePO4 : Photo

According to a measurement the seller has emailed me these batteries may have an internal impedance as low as 1 milliohm (see first attached image). When discharged through a clamp at a 10A rate the combined impedance of the clamp/wires + battery is about 9 milliohms (second image & third image).

Additionally, to my knowledge the lifespan for LTO cells can be very long - many thousand charge/discharge cycles.

A link to the ebay ad is here:

Toshiba 2 4V 3Ah Lithium Titanate Li ion LTO Battery Cell 180 Amps Current | eBay

For a bit more information on these cells Toshiba lists some information on their webpages:

“ŒŽÅ‚Ì“ñŽŸ“d’r SCiB�b2.9AhƒZƒ‹

The European EV/GWL company also has posted some measurements on LTO cells (another brand though) which can be found here:

lithium & solar power LiFePO4

As far as I can see LTO cells can be charged as a normal Li-ion battery when observing their lower voltages.

FYI in case it may be of interest to others here ...

Cheers 😉

Jesper

Hello from the multiway section. This is my first time in another section of this forum.

As the title states I want your opinion. Data also accepted. Distortion measurements appreciated

Check out the pictures. What I am created is a ribbon tweet, planar mid, woofer studio monitor for my office. Ultra low distortion is my aim. I was hoping to find a driver to play from 800-40 hz at the bottom end. Beyond 40 I don't care much as I can't hear any lower than that and it won't play at an SPL level I would be able to feel. I have 0.38" cubed to play with. I can make the port as long as I want. Maximum diameter 7".

Other option is to seal up the woofer and try to integrate a subwoofer. In which case I would run a big cone. Probably a 15" sealed. Or make a ripole. Or make a push push. Not sure yet.....

Here's my options really:

1. Run an Epique 5.5 as my woofer. Run it from 800-38. Make the stand of this build the large port necessary to run this. Call it a day.
Cons of this (there are always cons): I've seen only one distortion measurement of this driver and it sits around 1-1.5%. The other drivers in this build hang out under 0.5%, nearer to 0.2%. This is going to make the woofer the driving factor of distortion. Additionally I would now have low frequencies shaking the mid and tweeter. I suppose a push push would make that go away but then I have double enclosure space to deal with....

2. Run a low distortion driver like the SB Acoustics Ceramic 6" and seal her up. That rolls off around 100 hz. Then I run a sub and attempt to integrate it. I've tried this with friends subs and it never quite matches their monitors correctly when changing volume (I have a lot of musician friends). It is VERY possible I just have no idea how to do it properly. In which case, I'd love if you'd point me towards something that explains the proper way to do it. Or just tell me. Either is fine. I'd run a big cone sub or fiddle with a ripole for fun.

3. Some other option or driver I am unaware of but you know about and want to tell me about.

I'll attach a couple of the simulated XOs (everything but the woofer is real measured data, the woofer is traced data) and a picture of the current enclosure design which is subject to change. The low end is not reflected in the XO currently.

Let me know your thoughts you beautiful bass heads!

I have two of these lovely chips.

€150 + shipping at cost.

R

Hello,

All in the tittle,

I have a DVM (6000 taps) but looking for an easy tool to say if a fet/mosfet/BJT is dead (littles as well as power transistors), and also give the numbers for good matching enough.

For now I try to test Fet with the buzz continituiy of my DVM : when going to buz with fast intermittent way : Fet OKAY ; If continous : FET bad ; I did it with J113, seems reliable.

But would likee something more easy and also sort out.

I know some cheap known tools, but have heard only bad things about it... At last some seems easy with smd pads and so on.... Gadgets ? I am only DIY casual...

Thanks

I haven't posted on here for many years, i've tried to reply to a thread but it says new members must introduce themselves first, so here it is 😂

Hi everyone 😊

Howdy!

I have had a Sony DVP-S9000ES for a couple of years now. It's really great sounding player for red book discs. Ever since I have owned it, it has had the problem recognizing the SACD layer of hybrid CD/SACD discs. I wasn't terribly bothered since I have so few SACD discs. Fast forward to about a month ago and it started having trouble recognizing red book discs as well.

I tried various things such as cleaning the lens with isopropyl alcohol and running through the calibration menu for both CD and SACD discs. Neither seemed to resolve the problem.

I took the plunge last week and bought a replacement laser from eBay from a US seller called Liberty Electronics. It arrived to me on Monday and I began the process of installing it.

I finally got the unit back together on Tuesday and it's now having some severe troubles. I can't get it to recognize any disc, but one DVD that I tried. No CD or SACD. I tried the calibration procedure again and it failed on every disc I tried.

When I insert the disc, it will spin up and then I hear/see the laser unit moving forward in progressive increments. It gets all the way to the end of the CD and then throws an error that just says "Error". I can clearly see the laser is shining as well.

I removed the anti-static solder blob on the laser before reinstalling so I know that is not the issue. Unless I bungled that somehow, but do not believe I did using my Hakko de-soldering station.

Just curious if anyone has encountered this before and what the problem might be. Damaged laser? Incompatible laser? Incorrect reassembly or possibly something damaged during reassembly?

I've read that the unit might need to be calibrated, but haven't found a ton of info on how to do that just yet. Also read that the laser's gain might need to be adjusted but I haven't found those adjustment points just yet either.

Any help you can provide would be appreciated. I've been spinning my wheels the past few evenings but still not ready to throw in the towel.

Hi all,

I purchased a ported enclosure of full range Philips AD12100/M4 drivers recently. The enclosure was 36" x 14" x 18" (Height x Width x Depth). Unfortunately that was too big for my room so I started putting them horizontally such that it would lay 36" along the ground the be 14" high up.

I recently read that these drivers were good candidates for an open baffle conversion so I've simply removed the body behind the speakers and placed them at an angle, slightly toed in as well as inclined towards ear height. This is obviously a starting point and I'd definitely "do it right" if this is the right way to go (remove ports on the baffle, fix the toe in and inclination angles, wall dampening, etc).

Currently I feel that whilst the clarity has improved significantly there is a perceptible drop in "body" when playing music, something that I'm trying to compensate with my subwoofer.

I was wondering if there is anything I can do to my setup to better improve it given the inherent limitations present in my room.

I paid about $100 shipped. I will accept the best reasonable offer. Untouched , includes build instructions and matching resisters.

Hello guys,

I am diving into the audio world as I would be interested to add a Surround/ Dolby Atmos to my living room.

I am trying to avoid wires and thus look into what could be done DIY & Wireless. Unfortunately, it seems that there is not many reliable protocols that are able to achieve bandwith & latency requirements of high quality audio.

Dolby Atmos FlexConnect -> Almost brand new, not much info.

Bluetooth -> Quickly read that it will not achieve latency requirements ?

RadioFrequency -> Have not look into that.

And finally, there is WiSA that is a proprietary protocol using 5.2-5.8Ghz frequency - One person seems to recently look into retro-engineer this protocol so it can be used for DIY, but not much news: Build a WISA receiver.
After researching a bit everywhere, I might have found a way to buy the WiSA transmitter and receivers without buying in bulk. I will not post the link yet as I would prefer to try first and update you later (but if you are really interested, please contact me in private message.)

In term of hardware, the idea would be:

INPUT & TX:
- A 2nd hand WiSA SoundSend that has the advantage to be Dolby certified OR from an eArc HDMI Audio extractor with I2S output to the WiSA transmitter.
(I also saw the Orange Pi5 has en eArc HDMI but I did not find any active project on that + the Dolby stuff would still be problematic if I understood correctly?)
- Transmit using a WiSA TX board.

RX:
- a WiSA RX board has I2S & I2C outputs and thus could be use to a mini amp / DSP ? This is where I need your expertise !
HDMI Extractor ---I2S---->TX --Wireless--> RX --- I2S---> Amp/DSP? ---> Speakers.

Pin out is just for schematics

One of my concern is how usable is the RX I2S output as it could be encrypted. After long research, I do not believe it is (see schema of a WiSA DAC and a WiSA ready Amp that used to be sold) but only real test will tell.
WiSA DAC:


Looking forward for your feedback,

I probably have a better chance of winning the lottery but no harm in asking 😁

Michael here ,. Love the old school Voigt transmission design. Huge easy ways to deminish driver misbehavure. Less xover parts or usually none if single driver. Lots of good ones now! Forget phase alignment and xover complications. The quarter wave "tube" design eliviates fr peaks and valleys by canceling them out instead of excentuation them in some designs. Then they add expensive xoverer to cover up but often loose good qualities also. Awsome video on YouTube "worlds second best speaker" explains everything by a really smart engineer. I made a pair and they are really easy to build. This design has very good bass but the best thing is a very "airy and open" soundstage.. they surprised me even with cheap drivers. I have made all sorts of "made up" designs , some crazy, but this is what I will always experiment with. I put a long thin port at the very top that made a huge difference in opening these up and got rid of the confined boxed in sound we all have come to get used to. Look at video and see what you think.. Im a convert! Michael marmarasmichael@gmail.com

Hi guys,
I purchased a Cary SLP 90 clone board sadly with no further instructions. In two of the videos of the ready made SLP 90 I could make out the transformer markings as
220 v AC secondaries which I find very high for the 12AU7. Max rating for this tube is with most manufacturers about 330v DC.

Two questions: will the lifespan of the tube suffer with this high voltage?
If so can the circuitry stay the same for a reduced plate voltage?

I tried to get the schematic but was unsuccessful so far.

Klaus

Sony TA F770ES with remote.
I have here for sale this amplifier in perfect working condition and in great visual aspect.
Everything is working just fine,sides constructed in solid rosewood, seeing by having more
equipment of the genus.
For buying check here or get in touch:
https://www.ebay.de/itm/326342363980

I was looking for a nice small amplifier that would be good for moving around and testing things like preamps and such. I have a Crown D60 which is decent and thin, but I have a friend offer me a Jamo MPA-101. Awhile back he tried to get into electronics, but gave up fairly quickly. He did do a “recap” on it and I’ve gone over the work and it looks decent.

The front LED doesn’t light (it works), it has high offset (200 mV) and it seems to have odd power up behavior. So I wanted to isolate the power supply to make sure it is good to go. Clearly the power on led isn’t working so the power supply isn’t good.

I noticed that there are two large resistors and both are showing signs of heat stress, here is one of them. He is turning brown in the middle.


So I thought I would disconnect everything possible from the power supply board. I removed the fan, the LED, and both amplifier boards. So it is just the one board and the only wires connected to it come from the secondary of the transformer.



I powered up and immediately for items on the board got very hot. There are two 1 watt 15v zener diodes and I would say within 6 to 7 seconds they were at about 230-250 F.




The other two items were the two large resistors which were right at or just slightly above 200 F, the photo is of the cooler of the two.



I’m thinking this might not be normal, not sure if I’ve seen a zener diode get this hot.



The two diodes in question are ZD2 and ZD3. The two resistors are R79 and R80.

The 15 V coming off of the Zener diode is actually closer to 17 V. I understand the voltage drop across those resistors is determined by the current and the heat created is from that current.

Is all this heat strictly being caused by the two zener diodes pulling that voltage to ground? I have not found any shorts on the board, I pulled both of the diodes and they measure perfectly fine out of circuit on a zener diode tester. They are obviously faults on the board as this board is not providing the voltage to the front panel LED, but not sure if these are related. I just want to make sure that the behavior I am seeing with the extreme heat on these two dies and two resistors look OK. If these two resistors are getting this hot strictly from the two diodes pulling the voltage to ground I can imagine they get quite a bit warmer when everything else is connected to the 15 V rails. Well I guess not that much more is pulled. Here’s the other portion of the power supply.


Dan

Hello,

im wondering whether there are more easy to implement dac chips im missing

AK4993
TDA1387/TDA1541
CS43131/CS43198/CS4398

im specially looking for a solution that can play DSD and PCM

i recently found out that CS chips sound quite good, still wondered whether i should try AKM, i also never tried older chips like the TDA1541, really unsure where i should my effort in... do you have some advice?

i had 4-5 ESS dacs, but compared to the recently tried CS chips they all sounded rather bright or even slightly distorted in the highs, so unless you have a good very good reason with recent chips i rather try AKM/CS in terms of new-ish chips or some older R2R designs

Looking for 10"~12" subwoofer driver. Used good condition OK. Need to downsize my 15" as I moving into smaller house. Got one your not using?

Up for sale is my lightspeed attenuator by George stantscheff.

This is made with dual volume controls for separate left and right attenuation.

Askinb $450 or best offer.

Buyer pays shipping and paypal fees.

Thanks

Happy new year everyone!

All the best! 🙂

As i didn't have any luck with my previous project (Vestax cdx 12) i decided to up-cycle the DAC of the Vestax.

Not that bad, not that good but i'll give a try.

BB PCM1710 used in several PC players and also in AN cd1.

As i'm gathering information about schematics im nearly at the end of the pcb.






It will be quite simple according to the two schematics describing all the necessary connections between CS8412/14 + PCM1710.

The only thing i will need some help is Pin 16 of Cs8412/14.

I'm thinking it will be great to have a sampling frequency indicator & error indicator (both in leds)

I've found a nice Cs8412 spdif indicator




In this case SEL (pin 16) is LOW so we can have error/frequency info selected according to datasheet.

I was wondering if with SEL in LOW we can enable de-emphasis also.. Seems not but a person with greater skills may know better.

Also how can we add the 96Khz sampling freq. in case we use the pin compatible 8414?

And the pcb so far..




Thank you all 🙂

For sale pair of monitors, you can use this for center speaker, surround or monitor with subwoofer combination. Verry good sounding speakers in good order and verry nice designed loudspeakers. Price 300 euro for pair.

I want to buy 1 or 2 genuine WM8804

​

Lastly (or not?),

I have torroidal transformers from toroidy.pl, unused

--SOLD-- TTSA0400 - Transformer AUDIO TSA400VA - voltage to 50V
Output voltage: 2 X 24 V; Mounting pad: Filled epoxy resin #07
Price currently ca. 90 Euros + shipping etc.
I offer one transformer for 60 Euros, two for 100 Euros, plus shipping from Germany.
--

and one piece of the following:
TTSA0050 - Transformer AUDIO TSA50VA - voltage to 50V
Output voltage: 2 X 22 V; Mounting pad: Filled epoxy resin #07 1 pcs. 126,00 z

current price ca. 35 Euros. Offering for 20 plus shipping from Germany.

PCBs:
2x Universal Power Supply $25.00 each
2x Super Regulator $19.00 each

Also, i have 3 chinese PSU PCBs that look and feel very solid, they go I think for about 10 USD on ebay. If you get something here and want one, free on the side, just let me know.

Next some PS caps:

SLPX223M035H4P3​

One is about 5 Euros +VAT +shipping, so I will offer them at 4 Euros plus Shipping. I have 18.


I think that is it for the time being. Thank you. I hope I didn't spam the forum too much.

Hi, next up -

a populated set of F5 V3.0 boards - 25 USD original and one pack of F5 Mosfet kit - I can't find the past or current price, seems like google ate the email.
Given that the F5M was sold for 55USD in kit form,

I offer these for 40 Euros plus shipping from Germany.

Can anyone give me some insight into this. The power switch is sticky. I have sprayed it with contact cleaner on A few occasions and it would work for A short time and would stop. Some days I can't power on and others I can't power down. Do I need A new switch? Should I take it apart and see where it's getting hung up? Just curious if anyone has run into this. Thanks for any feedback.

hi tube friends
i have built few of those nice green tube indicators
all work, but some have even without any signal small green strip on top and bottom
I wonder if the vr2, please see the schematics, is there to adjust something
my circuits do not have vr2, just the input signal sensitivity
thanks

2 pieces of Dayton ES140TiA-08. Unused. Purchased in 2020 from Parts Express.

Asking £50 GBP each + P&P.

Datasheet Here.

Hi Folks,

Can anyone know what the purpose/function of my red circuited wiring for this SE OPT Primary at 1K6 / 30W ?
Which circuit and example used for ? Any benefit to the AMP design ?

SOLD!

Hi,

I have to sold 2 x NPC - SM5842AP

New and unused, I bought them many many years ago from Spencer fetaudio.com . Originally planed for my D1 DAC but .....

Price each: asking for 75€ each (or make a fair offer)
Shipping: depends which shipping options you like and to shipp to where (+ PayPal fees) ;-)

2 Lundahl Interstage 1660/18mAh with Lundahl Cover for Eur 140.- / each
2 Lundahl Output 1623/90mAh with Lundahl Cover for Eur 250.-/ each

Hey

I have a subwoofer from Svs, model pb2000, unfortunately the subwoofer's internal amplifier burned out.
I couldn't find a diagram online to figure out how to fix it.
While browsing the web, I saw that there is another company that uses the same amplifier.
Does anyone know which company?
Does anyone happen to have the diagram? Or what is the best way to amplify the subwoofer so that it works properly? Even with another external amplifier. Thanks.

Maybe I’ve found my home…I’m a fire alarm technician by day and I refurbish and often upgrade the sometimes broken and sometimes distressed speakers that come my way when I’m not at work.

I have a Peak ESR meter that I use to match electrolytic capacitors when they are not being replaced with polypropylene metal film capacitors.

hey, I'm working on upgrading my old speakers and I found a lot of interesting information here 🙂

It is my side project, having some electrician background and extremely limited time with two children 🙂

Unfortunately I'm not an electrical engineer, I plan to start college soon to learn how to build power supplies and design power amplifiers

Hi Folks,

New member here.

I'm looking to build, or maybe buy, a small portable stereo combo amp for a digital piano/ synth. The closest thing to what I'm looking for is probably the Roland KC 220, but I dont want to spend €550 on it and I don't need it to be battery powered.

For whatever reason, most keyboard amp manufacturers don't make stereo amps and so if you want stereo you have to buy two and most people use active PA speakers anyway as they tend to be much better. This is unfortunate as most modern digital pianos sound rubbish in mono, even when summing the left and right together.

I want something to take along to a small jazz and blues group practice. It doesn't have to be high power and I'd like something as light as possible. I currently have a few options available, but they're all too big, too powerful and too heavy. For instance I have a Warwick Goblin bass head which is 200w and smaller and lighter than a Jack Reacher novel (and not as many people die horribly when I use it), but it's mono and the cab I use with it is a 4x8 that weighs 30 kg.

I'm thinking of building a small speaker cab, with maybe two midrange speakers to give the stereo and a shared woofer. Probably 2x 4 plus an 8 or a 10. I'd then buy a small class D stereo power amp module to drive it, or maybe a second Goblin. I only really need 20 or 30 W rms per side, probably even less.

I could either sum the L & R signals via a crossover for the woofer, or just drive it (with x over) from my left channel.

Has anybody got any advice on the cab ? Good idea or dumb ?

I was contemplating building a linestage based on the ARC Ref 6 or later but I cant find anything anywhere regarding it. Does anyone have any intel? I spent some time trying to decipher pics of the PCB online and it looks like it is similar to the ref 3 but implemented a current sink on the CF along with some regulator upgrades. To be honest it seems like each new iteration from ARC moves closer and closer to Allen Wrights designs but with the 6h30 tubes.

Reposting my Pass Front end preamp I no longer need. I am asking $300 and free shipping anywhere Conus.

2 balanced inputs
2 Single ended outputs
Alps 4 gang pot
VRDN PSU
Silver coated ofc
Wima input and output caps
Modushop Hifi Galaxy 330x230
chassis
Posts to easily change gain resistors

Shipping from Houston, TX.

Selling my Sennheiser HD650 headphones and a Whammy headphone amp I built for $600 shipped.

I used all vishay dale military resistors, Nichicon caps, mogami wiring, and a stepped attenuator volume pot. Opamp is a RC4580 included.Chassis is a Galaxy 3U 230x230 from DiyAudio.

I am only selling it so I can fund a balanced Whammy.

Shipping from Houston, TX.

I’ve been having some issues with the audio in my Becker BE1480. I am considering sending it to Becker in NJ for them to repair, but I’ll try to see if this is something I may be able to fix myself.

There are 2 issues depending on whether the unit plays a cassette tape or radio.

1) When playing a tape, there is only audio in the right channel. What’s more, it plays correct when set to play side 2 of the tape, but plays backwards when playing side 1 of the tape. I’ve had this issue for ~6 months. I had the unit out to visually inspect the mechanism, but nothing struck me as apparently causing the issue. I have also cleaned the tape head with rubbing alcohol.

2) The audio from the radio will play in left or right speakers and/or front and rear speakers intermittently. Only sometimes do all four speakers work at the same time. I’ve had the issue for ~2 years and I have yet to find a consistent pattern of when speakers work or don’t work. I can often increase the volume and at some point the speaker(s) will start working. I tried replacing the front speakers, but the issue persisted. That tells me that this is an issue with the head unit, not the speakers themselves. I also replaced the fader switch last year so that should not be an issue.

I would greatly appreciate any suggestions.

Hi everybody, this is my first post here. I have an amplifier mod that I'm really happy with. I wanted to post about it, and this place looked like a really good fit. Hope you enjoy it!

Many years ago I bought a Groove Tubes Spacestation SFX-100 for my keyboard setup. This amp caught my interest because I was never able to pull off a useful stereo sound while playing live. It is based on the Center Point Stereo concept developed and promoted by Aspen Pittman himself. The idea is pretty ingenious. It uses a novel application of Mid-Side processing, which historically has been used mostly in recording/mixing/producing, but turning it on its ear for live playback. What they did was to output the Mid signal (Right plus Left) through the front center speaker system, and the Side signal (Right minus Left) through a side-mounted open-frame speaker aligned with the center of the Mid speaker. (To avoid confusion, note that in the context of the Mid-Side language here, "Mid" means "middle", and not "midrange".) The two signals then propagate outward where the waves interact constructively and destructively to reconstruct the Right and Left portions of the sound everywhere in the sound-field. Because the stereo information all comes from a single point, in a large room you still can hear both "sides" of the stereo, which is really hard to do with separate Right and Left speakers - usually, except for a relatively narrow "sweet spot", either the Right or Left side will inevitably dominate over the other. I have to say that the CPS effect is pretty dramatic, even impressing this crusty "experienced" live performer/engineer. You can actually walk around and hear stereo just about everywhere in the room (or at least a useful approximation of it), both on and off the stage.

Now, my SFX-100 is from an early design, and it is clear that they were still ironing out some wrinkles. Here are some pics off the web of what the stock unit looks like (mine was the same):



The pic on the left is the whole cabinet, with the bottom being the open frame for the Side speaker mounting. The pic on the right is looking straight into the bottom left of the cabinet, showing the back of the Side speaker.

The Mid speaker system (meaning "Middle" here and not "midrange" - just for clarity) is pointed straight out the front, and has a 10 inch Eminence driver with a coaxial compression horn. The horn does well with the "bright" portion of the highs, but falls a bit short for the "crisp" part. The designers addressed this by tacking on a super tweeter, which appears to be a piezo type connected in parallel with the horn. When listening close to the piezo, it does put out some crispy highs, but at a much weaker level than the main drivers, and has that "splatty" quality so often associated with piezos. Unfortunately, piezos do get a bad rap because of a huge misunderstanding: even though they don't technically need a crossover to function without damage, they still react badly to huge low-frequency transients, leading to the splatty sound. In fact, a properly designed crossover not only smooths out the sound of a piezo beautifully, but it can also greatly increase the operating life. (More on this topic as we get deeper into the mod.)

The side speaker is a 6 inch coaxial. The front-wave of the Side speaker shoots the R-L signal to the right, and the open-frame design ingeniously allows the back-wave of the Side speaker to shoot the L-R signal to the left. The hole in the middle of the magnet is to allow the back-wave of the coaxial horn to also shoot some highs out of the back of the Side speaker (which, again, is goes out the left side of the cabinet). Note that in this design, there is no tweeter for the side signal. In the wider sound-field, starting about 3-6 feet away from the speaker, the three waves combine to create what your ears perceive as Left toward the left, and Right toward the right. At least that's the general idea, and it actually holds up pretty well.

What I found is that the piezo on the front did more harm than good to the Mid sound (to my taste), and the total lack of the tweeter on the Side speaker left the Side portion of the sound very muddy and boxy. After some thought, I decided that adding the right choice of high-output tweeters for both the Mid and Side drivers, along with nixing the wimpy piezo, would really go a long way to filling in what was missing.

I'll go into the choice of tweeters and the crossover design in the next post...

I've got a very basic kenwood turntable here. It has a DC motor rated at 12V and a simple power supply.

It came to me non-functional. On investigation the internal fuse was blown. The fuse sits between the transformer and the rectifier (i.e. not on the mains side).

When I replaced the fuse (with the correct value) it initially ran OK. For good measure I decided to replace the smoothing cap as it looked suspect - although I think it was probably glue rather than leaking electrolyte that led me to doubt it... It ran OK for a few minutes before and after capacitor replacement.

I then tried it again and the fuse blew right away.

According to my multimeter the low voltage side of the transformer is providing around 10V AC.

I have checked the diodes (removed from circuit) - they are all OK.

My best guess at this stage is either the motor is bad and drawing too much current, or perhaps the transformer is producing inadequate voltage and similarly causing the motor to draw too much current.

Any thoughts? Inclined to cut my losses at this stage...

This thread is for discussions about the Mezmerize B1 Buffer Pre Amplifier. For more information on this product, please see the product page below.

• Product Page
• Schematic
• Bill of Materials
• Dimensions

Threads on diyAudio that relate to this product (If we have missed one, please post it in this thread and we will add it to the list):

• Build Thread: Mezmerize Build Thread
• Build Thread: http://www.diyaudio.com/forums/anal...otrodded-blue-dcb1-build-132.html#post2700123
• The B-1 Mezmerize is based on this: B1 Buffer Preamp

Enjoying this recent acquisition looking new, through an 85 watt per side Yamaha receiver. I am hearing the most coherent bass than I have heard before from an enclosure of this size.

When I set up a pair of Tannoy E-11 (that I regarded to have the most natural sounding bass within the range bookshelf speakers operate in) for an A/B test, on the Wharfedales male vocals sounded like they were far forward of the rest of the music compared to my reference Tannoys.

Questions - was the Diamond line designed to do this on purpose or is it a side effect derived from something else the Wharfedale engineers were attempting to correct with the crossover?

I feel kind of silly asking, as it just occurred to me that the voicing the different product lines of Wharfedale is more heterogenous than other brands - I don’t think that this was true in the 1970’s, but I think that it has been true since the 1990’s.

Hi does anyone have one. One of mine has failed.

Apparently there are a few variations. Mine has the number 8778 printed on it.

Thank you, David

Hi 👋

I designed and 3-D printed experimental pod speakers. I’ve tried to keep the cost down as much as possible, which is important me. I chose the two following drivers for my tweeter and midbass enclosures:

Pioneer TS-M800Pro

Dayton Audio ND25FA-4


I chose a cheap crossover from Amazon is there any problem to use it or better to buy a different one?




Here is my speaker design concept:



Optional sub pod:


The color is not finalized. You can say it’s ugly too 😆

I have this amp that uses 2 NE5532 and 1 TL072 in the output
the 2 NE5532 are signetics, and the TL072 is a TI

Should I change those with newer op amps ?

The amp is a Hafler Pro5000

see schematics

I’ve had a chance to play with the Sony 2SK79 and am hoping to try out other small signal SITs. Looking at options for a SIT FE in my OPT-coupled SIT amp.

Hello everyone, I'm new to the forum, but I know there are some very skilled technicians in this group.
I'm slowly building my small audio repair lab, and one of my projects is to build a tube audio amplifier.
Among the instruments I’ve painstakingly purchased, I have a beautiful HP-339A distortion analyzer… the only problem is that it doesn’t work!

I’m trying to repair it, but I’ve encountered several difficulties.
The oscillator works correctly; on the oscilloscope, I measure a perfect sine wave with the correct frequency and amplitude from 1 Hz to 100 kHz.
However, the notch filter does not track properly. The LEDs indicating frequency adjustment often stay lit, even when using the internal oscillator directly connected to the distortion analyzer input.

Occasionally, the notch null occurs (usually when the third frequency knob is set to 1x or 100x, almost never at 1k or 10k), but most of the time, it doesn’t.
The problem has worsened over the past few weeks. I’ve checked all the electrolytic capacitors in the instrument, including the tantalum ones, without finding any issues.
I also cleaned the frequency switch contacts with isopropyl alcohol, but it didn’t improve the situation.

Therefore, I’m seeking help from anyone who might have faced a similar problem.
Thank you!

Greetings from Vietnam, I'm Glad to be here to start build some interesting thing like speaker, thanks for accepting!

Hi everyone, this is Roberto. Thanks for the best audio player ever made.

Ian Canada FifoPi Q7II + TransportPi AES + PurePi II complete stack with accessories and Lifepo4 186500 batteries. Will include RPI4 1GB with 16gb sd card for free. Used for less than 100hrs. I am going active with minidsp so it no longer fits in the chain. Location - india. Price- Rs 43000($510)

There were two different goals that forces these ideas and concepts:

1) Only the adjust free power amp concerning bias adjust for idle current
(self biasing - I know only the Quad 405 current dumping amp and some related topologies)
2) Additional no leaving the Class A operation and low idle current at the same time
under all load conditions > 4 ohms (I know only Threshold and Mark-Levinson - Madrigal)

Where I can find an overview of a wide range of commercial brands/ models so as topologies concerning this two categories (only push-pull topologies - not single ended)?

Here patents/examples for this topologies:
Patent US3995228
Madrigal Library: Adaptive Bias
Patent US4160216
(automatic and dynamic/adaptive bias for classA under all conditions without external bias adjustment)
Patent US4077013 (automatic Bias without external bias adjustment)
http://www.diyaudio.com/forums/solid-state/1573-linear-tech-lt1166-chip.html (automatic Bias without external bias adjustment)
Patent US5216379 (automatic and dynamic bias without external bias adjustment)
http://220.232.128.43/audio/quad405/Current Dumping Audio Amplifier - PJ Walker.pdf (current dumping - ClassB without external bias adjustment)

P. S.
In this case also this threads could be of interest:
http://www.diyaudio.com/forums/solid-state/162559-new-class-super-non-switching-need-revival.html
http://www.diyaudio.com/forums/pass-labs/104399-importance-being-biased.html
http://www.diyaudio.com/forums/solid-state/58561-low-biasing-high-biasing-class-ab-amps.html
(complementary push-pull FET output stage with no source degeneration resistors and good working of bias control - i. e. no variation in quiescent current at the same time).

I posed this question, because I'm looking for a simple answer as to why this resistor is needed In series with the speaker when measuring impedance.
My thought would have been that you use your amplifier to send a signal to the speaker, staggering the frequency sweep to one or two seconds at each. frequency and measuring the voltages at each frequency across the speaker. Have an ammeter In series with a speaker. To measure amps. One can then plot a graph of the impedance response.
Please keep in mind that my knowledge is at beginner level, and if you could, think of the simplest individual when constructing your answer. I understand equal. V=IR., but not a whole lot more.

I am hearing a low frequency hum at higher volumes when using my turntable and upon searching as to why that might be I saw a video saying to be sure to have your turntable grounded to your pre amp, receiver, or whatever, the problem is I see no ground lug on the stated turntable however there is a ground lug on my receiver?

Do I have an un-groundable turntable?

Thanks

I wasn't sure where to post this so apologies if it's in the wrong place.
I don't know much about what's available, brands or prices etc..
I'm in the UK and Amazon are selling a trio of JJ ecc83 valves for £50 ($64 ish for our American friends).
Is this about the best I can get for fifty quid and no more!
It's a trio I need btw, and I'll be looking at replacing the rest of the valves in the amp at a later date.
PP EL84 amp btw.

This is Vlad's kit. First image is what he provisioned to me, essentially complete without chassis, wiring between boards, input/output hardware, power inlet/fuse holder.

1541 chip, non-oversampling, 6N2P-EV NOS tubes, nice caps.

Second image is kit housed in larger Galaxy chassis supplied by DIY store.

Fired right up, sounds superior to the low end Project e DAC as expected. A really good value and step up. I run an old high end Sony CDP into a Monarchy anti-jitter box, haven't tried streaming contemporary sources.

The first "Miss World Pageant" winner of 1951. From the Wall St Journal:

One evening in 1951, over dinner at their family’s home in Stockholm, Kiki Håkansson’s older brother—who had once told her she had “the face of an angel and the body of a pig—proposed entering her in a coming beauty pageant.

Håkansson said she wasn’t interested. Her brother entered her anyway.

Next thing Håkansson knew—and in retrospect, much of her life would unfold in this same, less-than-fully-autonomous way—she was at the Lyceum Ballroom in London, competing in the first-ever Miss World pageant.

Miss World is now the longest-running major international beauty competition in the world, having preceded Miss Universe by one year. It remains a glitzy annual event and has expanded its focus to include contestants’ humanitarian work. But that first summer, when it was a part of a much larger event, the point of the competition was simple: Its official title was “The Girl Bikini Contest of the Festival of Great Britain.” (Because contestants from various countries entered, the press nicknamed the contest “Miss World,” and the next year the pageant officially adopted that title.)

Hi,

as a followup to my othe thread (New diy open baffle project: 3-way with AMT) starting my open baffle project I am a bit further now in decision making:

Tweeter: AMT23D6.1-R (88dB, 8Omhs) is already ordered
Mid woofer: Audiotechnology C-Quenze 18 H 52 06 13 SDKA – last perhaps in a version with the J-magnet instead 90dB

I am now looking for a matching subwoofer, xo is planned around 200 Hz. I am thinking of one of the following:

• Acoustic Elegance Dipole12 or Dipole15
• Supravox 285 GMF
• SB Audience Bianco 15OB350 Open Baffle (or the 12OB150)

I would prefer the 12" drivers as I awant to build a rather slim baffle but with side wings (U-frame). I tried to chosse drivers with higher sensitivity to compensate for the baffle loss for low frequencies. Are there reasosn one of them would not match well with the above mid/high drivers?

Another question:
Is there a way to simulate U-frame baffles? I wand to make them triangular shaped, is there a way to simulate this as well? Can I use Basta! for this?
Is the response the same when I "flip" the wings to the front as Basta! can only simulate flat baffles as far as I know....

I am searching for a strobe light for my Micro Seiki DDX-1000. According to the parts list part designation is "NL-77". I was checking the archive of this forum and it looks like that this part is NLA. Does anybody have an idea how to fix this or even found a new source for this neon light? The light is internally pulsed so a direct hook up of the light to line voltage and -frequency is not possible here.

Hello everyone and thanks for accepting me into the diyAudio community!

I work as a Broadcast Technologist / Electronics Technician at a local college here in Calgary. Before coming to Canada, I was a Telecom Technician, so my career is a diverse one 😉 but basically revolves around electrons! It's same with my hobbies: any DIY electronics, ham-radio, computers, programming, house-fixing, woodworking, ...

diyAudio popped up many times when I was searching inter-webs for a solution to a problem. Finally, decided to join you for my own benefit and also to try and help out other members if it's something that I have some sort of expertise. At the moment i don't have many projects going on. Latest one is tinkering with an old Sony STR-V2 receiver whose amplifier doesn't work any more. Instead of fixing it, idea is to use a class D module as an output amplifier and build an Arduino controlled preamp and audio switch. Prototype of the preamp is in the testing phase, it works. It uses NJW1194 - digital volume and tone control with 4-input switch. Project is going slow a bit, since we are in a house moving mode, which will be over by spring, i hope. Until then, I might not be a very active.

Cheers to everyone and thanks again!
Goran

I'm a new member from Europe. Hi-Fi audio is my love.

Hello,

Once again with a DAX problem. I now have a DAX decade balanced that works great on all inputs but it came with the ADX analog to digital converter that allows to use 3 different analog inputs with the DAX and its built in preamp. The DAX sold with this option have an additional board and a differently programmed Microprocessor. My issue is that the DAX can command the ADX module, correctly switching between the 3 inputs but it doesn't lock on the digital signal fed back from the ADX through BNC coax. Any other dac I tried, equipped with a BNC input does lock on the ADX without a problem and it sounds good. The actual BNC input on the DAX works fine with other sources.

At one point the DAX managed to lock on one of the 3 inputs but displayed Ncode on the screen and there was no sound.

Happy Thanksgiving everyone! We have a lot to be thankful for! Safe travels to all that are moving about today. Have a good weekend as well.

Hi folks,

I'm a casual builder of a lot of things, whenever i need something, ranging from sketching to programming, a little music, grafics, things in and around the house, shelves, modification of furniture, piping, recumbent bikes, bike trailer, car trailer mod for the recumbents, pc, audio, mod of speakers, and finally my very own omnis (for the bedroom) which i'll introduce and share with you later - and are the reason i registered here...

i was long "in love" with my Duevel Planets, which perform really great with any kind of music, all 3 amps i've tested them with and in any room and environment i tested them - true omnis in every meaning. They are in the music room (named after the piano and the keyboard, not the omnis), and i have a 6.1 set in the living room consisting of Jamo Speakers I purchased bit by bit during my studies and a Denon digital surround amp, 20yo meanwhile - time flies, and a multi room streaming system consisting of two Raspis connecting to the amps via bluetooth. Im a bit of an audiophile but not that very much that i would spend a lot of money on that, i like 3 dozen styles of music, and a handfull i really dislike and as written above i have a lot of other hobbies and work to do...

regards, Dan

Hi there,

Someone needed with knowledge in speaker measurements.

I am using this bible by Kimmo Saunisto for measurements speaker simulation: https://kimmosaunisto.net/Software/VituixCAD/VituixCAD_Measurement_REW.pdf
Most of it is clear and made for newbies, like me, but some parts of it still are confusing, one of it is related to nearfield measurements. In page 9 of it there is one sentence, which is very straightforward, but still leaves more questions than answers:

"Locate woofer cone close to floor or wall to make half space conditions at LF."

What does it mean? I measure farfield measurements of speaker with REW at home, with "good enough" conditions - driver at ~1.2m height from floor, and distance is around the same or more from nearest walls and big objects. Usually it is 1 meter distance from source to mic, as in most instructions. Gating is ~4-4.5ms. Then I move microphone stand close to the driver, at ~0.005m distance and measure it. The same for the BR vent. Then I do importing into Vituix and start sim.
EDIT: Yes, I do the merger and everything else as in this instruction

The question is - do I have to move speaker close to the wall when doing nearfield measurements??? That instruction says that, but I haven't found it mentioned nowhere except there. If I simply put it close to the wall at 90 degree angle, I am getting results of big SPL boost at ~150-500 Hz and drop below 150 Hz. When I import it into Vituix and do exactly the same with both nearfield measurement options the crossover needs to be adjusted a little. That is for 2-way. For 3-way or 4-way speakers the data for biggest woofers will get skewed even more. And yes, with near wall measurements the simulation looks uglier. I don't care much about the "beauty" but more about accuracy.

Can someone with experience comment about this?
Thank you.

Hello. I have a pair of Mission 753's that were donated to me by my son. I have enjoyed them for the last 2 years as a significant improvement to my listening despite having a cheap amplifier. My amp is an old Cambridge 30watt thing with a bi-wire feature which how iy is connected to the speakers.
Over the last month one speaker had begun to distort, then it increasingly started to fade in and out volume wise and recently it has began to play up and then drop out for extended periods. I have swapped it over at the amp output and the fault remains and the good speaker stays good when swapped.
Help to work out what is going on and how remedy this would be appreciated.

Thanks.

Hi all, please forgive what to a lot of you are very newbie questions. I have searched quite a bit for answers, but it's kind of hard to digest and apply everything in practice...

I'm building a subwoofer for music / HT use in my living room. It's going to replace an XTZ 10.17 (non-edge). For several reasons, I'm limited to a relatively "thin" and small box. I've bought a used RSS315HO-44 in very good condition that I'm going to use for the project. I understand this is a driver that should work well in small enclosures. Haven't bought an amplifier for it yet.

I don't listen crazy loud, but I like proper low extension, and I feel the XTZ lacks just a little bit in that area. It works OK enough for my needs, and I could probably have lived with it for the sound alone, but it doesn't really fit in the living room so I want to get rid of it. My living room has one open side, meaning the total room is quite large.

I was originally thinking to build a sealed box. According to WinISD, in a sealed box of ca 25 liters (I could go up to 41 liters), the driver at Xmax will give me around 97.5 dB @20hz and 104 dB @30Hz (700W) (using the SPL tab in WinISD). I believe this is around 1 dB better than the XTZ at 20Hz but around 5 dB worse at 30Hz. The -3dB point is in the mid 40s. If I make the box vented, 32 liters net volume (when vents, bracing, driver etc are subtracted), tuned for 24 Hz, vent pipe dia 9.74 cm, vent length 114 cm, I get 102 dB @ 20Hz and 110 dB @ 30 Hz, with a very flat response from 100 to 27 Hz. Port velocity is a bit high at 28 m/s max, but I believe I'll never reach that level with music, and for HT it might be OK. Driver excursion seems to be OK provided I high pass it @17 Hz. I'm thinking to stuff the box with polyfill.

Ok, so here are my questions:

1. Based on the WinISD simulation, the vented version seems like the obvious choice. It gives a lot flatter response in general, and a lot more dB below 45 hz. But still, I see a lot of people recommend sealed boxes and one of the arguments is that room gain gives the sealed box quite a bit more output in-room than the simulation indicates. What do you guys think? The sealed version is of course a bit easier to build, especially for a first timer.

2. I understand I could do EQ or even Linkwitz transform for the sealed box (provided I could get a proper DSP in the chain), but I would still be limited by the xmax of the driver, right? So I can't really get more output @ 20 and 30Hz than what WinISD gives me above?

3. Since I'm very inexperienced, dB numbers are a bit hard to relate to. I don't really know if 97.5 dB @ 20Hz and 105 @ 30 Hz might actually be quite sufficient for me. But as I said, I feel the XTZ lacks just a little bit (not much) of power for my needs in that large room. What are your experiences, what dB numbers would you think I should aim at (using the SPL tab in WinISD)

4. If I do vented, do you see a problem with the long vent pipe? I'm thinking to use flared ports (inlet and outlet). I know it's generally recommended to not go above 20 m/s but I believe my music listening will not exceed that, and for HT it's maybe not that important?

5. If I do vented, I'm thinking to use thin PVC pipe (HVAC air pipe) with 1.3 mm thick walls for the vent, and buy "aeroports" for the flared ends. Do you see any problems with this, or do you have better solutions to recommend?

6. The driver can be connected in 2 or 8 ohm configuration. It's easiest and cheapest to get an amp that can do 700 watts @ 8 ohm (bridged) as far as I can see. Does this give any disadvantages over using 700 watts @ 2 ohm (paying a bit more for an amp that is 2 ohm stable)?

7. Any general input or recommendations for the build?

Greetings from Western Australia: I have been messing with speakers, amplifiers, etc since the early 70's. I am currently setting up a system incorporating electrostatic panels from ER Audio, harking back to my early experiences hearing Quad Electrostatics belonging to the father's of girls I was dating.

A few years ago, I made a 814 push pull amplifier like this:



step-up tranformer as input stage, driven by a small amplifier.
It was nice but today I would like to make a more "conventional" amp with a tube driver.

As I already have a pair of LL1660 10mA, I wonder if a 5687 (200V/10mA) can drive the 814's into A2 region or definitively not ?

From the datasheet, control grid at +30V eats 10mA of current, will it works ?

It may be better with a direct coupled CF or even better with solid state but as I have these 1660's, I am curious..

I bought these tubes recently for some tube rolling from HotRox

Fantastic little tubes, but unfortunately due to high frequency damage to my ears, I have to sell them on.

Been used for approx 180 hours (150 hours burn in and then some listening)

These are a matched pair

Price - £95 GBP

Location - Glasgow (UK) - Can be picked up

eBay link is below for safe purchase

https://www.ebay.co.uk/itm/267080761574

I've been planning for stereo upgrading in my car. I'm going to build 3-way system. This is my very FIRST TIME using multiple amplifiers. I'm not sure if my car's electrical could support abundant amplifiers used. My car is 1983 380SEL.

Attached pics are diagrams of bi-amping vs. tri-amping that I could figure of:

• System A is tri-amping utilizing 3 amplifiers. The Soundstream amp is actually 5-ch configuration but it could be switched to 3-ch by bridging front and rear channels together.
• System B is bi-amping utilizing 2 amplifiers. The Soundstream amp now will perform 5-ch configuration so as to reduce an amplifier used--the tiny Sony amplifier.

As mentioned earlier I've never experienced with multiple amplifiers system before, I need advice from experienced people to suggest which system you recommend. And are there any modifications on my car's electrical system required to support the enormous current consumption for these systems?

Here is a diagram of power connection of tri-amping system with wire size labelled. I need assistance to review the diagram if it's acceptable and has proper wire sizes and fuse used.

PS. All components will be located at the rear trunk of a sedan except head unit, fuse, and battery.
PS2. The ga. unit may refer to AWG standard, I'm not sure. I just called it ga. following the user manual of Soundstream.