SPDIF coax/optical inputs. 35 watt stock power supply. RCA unbalanced and XLR unbalanced outputs. Direct coupled with ~neutral tonality. (brighter/"faster"/ tighter than my two CS4398 DAC). Opamps are National LME47910 (filter) and LME47920 (output)

$150 shipped CONUS Paypal only

Hey. So I've got a few TDA2822M ICs and all the passive parts laying around and I want to make a small battery-powered stereo amplifier. There's lots of schematics around, but they generally seem pretty dubious and lacking in citations. Does anyone have a recommendation, especially for a bridged build? Something that achieves the best sound from the chip, even if it uses a few more parts?

I know I can just buy a PAM 8403 built for the price of a Coke, but I'd rather screw around with perfboard and point to point.

What if i have to change 21194/21993 for 5200/1943?
is a problem the upper frecuency operation for the amp stability?
how it could be solve in the case?

thanks

Hi

I have an earlier version of this amp with the printed and not raised Technics logo. The amp is on a wooden rack which is in turn on a carpeted floor. If I wear a certain pair of slippers a static charge is building up. If I touch the metal case of the amp near the power switch it immediately shuts down.

When it first did this I thought it was a loose power cable. It comes back on again fine if I turn it of and turn it on again and functions with no issues. DC is around 2mv on both channels, etc.

I have recently replaced the speaker terminals as the original plastic twist lock ones were loose and breaking up. I have not used this unit much so not sure if it was an issue before the changing the speaker terminals.

This is not a major problem but was curious to know if anyone has any thoughts on the matter. The initial solution is not to wear static creating slippers!

Thanks

Hello Everyone,

I’ve been trying to deploy a circuit to protect my speakers as currently my power amplifier does not have one.
Going through numerous schematics on internet, most of these circuits required some form of vdc to function. However there are a few I found that don’t require additional power.

I’m not electronically trained and would need some help to understand this better. In the end, safety is top priority but and if I can have a circuit that doesn’t require additional power that would make my life so much easier.

Many thanks

Hello--

Awhile back I picked up a pioneer ke-1818 from the junkyard to put in my old tercel. Finally got around to hackin out the fire hazard wiring harness the PO put together, modified my bezel, got it all hooked up, aaaaaand....nothin. Checked power at the plug, and it is getting power at the constant and switched 12v wires with the key on.

Alright. Took it apart, nothing looks obviously bad. Scrounged the interwebs and found a barely usable wiring diagram. Using it as a vague guide, I went to checking a few things.

I have power going across the switch.

Checking the brain chip (IC951, PD4275B) GND is good and I've got 5.2v at VDD1 and VDD2. I would assume VDD2 is outputting voltage based on the arrow.

What does CE mean on the chip? I'm curious since it has a voltage value next to it and I've got no power going to it.

Also, where is the chip getting its power from? Since there is +12v going to it from the BU line, I am curious what pin that is.

Where would it be logical to check next? To me it seems like the brains of this radio is dead :/

Attached the wiring diagram I am using.

Hi.
Wrongly posted in components. So here it is. thanks to garrbage to point me in corect section.

I am currently trying to put together a good DAC AMP and DSP system "all in one.. "

So here is my list of parts. I am quite a noob regarding diyAudio, but I know may stuff around systems and programming and stuff.

So here is the list.

- ALLO VOLT+D Dual Mono Class D Amplifier 2x TPA3118D2 2x60W 4 Ohm

- AUDIOPHONICS DAC I-Sabre ES9038Q2M KALI EDITION Raspberry Pi / I2S & SPDIF / PCM DSD

- KALI ALLO / AUDIOPHONICS ES9038Q2M GPIO Adapter

- MiniDSP 2x4 Balanced Audio Processor board 2 to 4 channel


Here is missing a good power supply, I was reading the forums, but I can't make head and tales from what I read.

So some options are the

Allo NIRVANA SMPS or Shanti, are there other better solution at the price point.

AND the most important thing here, where on the forums should I post something like this.

Or I would be better with RME ADI-2 DAC FS, this one has DSP,DAC



Thanks anyone for help.

Reposted from redit.
Ned a little help with parts selection. AMP,DAC,DSP.. : diyaudio

In the pic ra2 is a 47 ohm resistor. When I put it in and turn the amp on it starts smoking. The amp idles at 3.5v so it's not drawing a ton of current. Any ideas what is causing this

I have a MAC 1500 in nice shape. I bought it as an investment, which - as all other true classic 60's gear seems to head for the sky - it remains at about the same value as when I originally purchased it off ebay...

This is the unit that's all tube, except for the phono stage. Worthwhile replacing transistors there, perhaps with modern day low noise equivalents, if they exist as a drop-in?

There's a lot going on tube wise in the FM section, including nuvistors, that I believe run (burn power) even when the input is selected to "aux". I've considered a switch to relieve this section of having to dissipate power when not used, but installing such would probably "molest" the unit from stock form considerably.

Perhaps the best thing to do is just sell it as-is, dead stock - and swallow the fact that it simply wasnt that good of an investment. Currently and for the last 7 years, its just sat in a cardboard box in the closet - no wood cover; that'd be an extra $250 (and an extra shipping parcel; no way they could be shipped together)

Thanks for any thoughts,

I have started building two 3way speakers using B&C 15NDL76, 8PE21, DE250 and Eminence H290B.

The enclosures are made from 15mm birch plywood, have a volume of 85L and are tuned to 50 hz.

Greetings,
Looking to gauge interest in a group in the NY Capital District and, western Massachusetts areas, or anyone else that'll make the trek to the intersection of I-90 and I-87.
Kind regards,
Drew

I have this amplifier which is getting + 70v ac on the outputs, the outputs are in good condition as well as the drivers any other item you can check?

Has anyone here just made one up?
I mean grabbing an LED, a photoresistor and holding them together with some light-resistive heatshrink?

Considering how variable commercial units seem to be and the efforts to make matching pairs as much as possible, I'm surprised I can't find any threads about making up your own.

ESP touched on this very topic here: Project 145

You can easily make them up at a fraction of the cost of industrial-made units, and you can probably play around with them a bit, tweaking distances, etc, to try and get matching pairs...

The other reason I started thinking about making up my own is that the two or three manufacturers I have found who make LDRs appear not to be RoHS compliant. The Advanced Photonix NSL-32SR and their variants aren't RoHS apparently. Neither are Excelitas Tech range...

For the cost of a few pennies, I'm going to put some together and will report back, but if anyone else has tried this, I'd love to hear your experience.

Hi all.

This is probably more a question for Chrisb than anyone else, as he's heard all the drivers in question. Happy for all opinions though.

I have built one of Dave's/Scott's MLTL designs for a 12pw. I really enjoy it. I'm now going to rebuild it in some fancy local hardwood, using the 12pw crossed over to one of a) MAOP 7.2, b) FF85wk, c) Alpair 5.2. I already have the MAOP and FF85wk and like them both. I've read many of the arguments about pairing 2 wideband drivers. I'm actually very interested in being able to miniDSP compare a very wide range of xover frequencies and slopes.

1/4 wavelength c-c spacing with the FF85wk and 5.2 would afford higher ideal xovers of ~500Hz or greater. I could probably get the MAOP7.2 close enough for ~400Hz. Although, I'm not at all convinced that I need something this low. Perhaps I enjoy the beaming of the 12pw when run full range. Perhaps I also enjoy midrange from larger drivers. These are the types of questions I want to experiment with by having such a huge frequency overlap in driver responses.

Any thoughts on which might be better? These will be biamped with tube amps. Listening space is about 4.5m X 3.5m X 2.75m opening onto a larger room. I sit about 3m from the speakers and listen to all kinds of music at moderate to low volumes.

I'd put them in closed volumes of: MAOP 3 litres, ff85wk and 5.2 about 1.5 litres.

Thanks for any thoughts everyone!

4 E88CC crossed swords tubes bought before the 6dj8 fever in original boxes never used (20 mn audition for two of them) .No gold grids on them just on the right is a 6Z31 Tesla ,ink is exactly the same . On one tube gold on the pins is gone never noticed before .
5 RCA 6CG7 clear top , 2 branded Pinacle, 4 Haltron, 2 Mitsubishi .No boxes but all unused and tested.
5 6X4 Ultron labeled as SQ, 2 Tesla 6z31 .6x4 miniature tube top made.
Can't test the E88CC properly at moment ,first triode is 0K but on second one the bias is changing and i get a false value .I think the shield need to be grounded .
If someone interested , offer in my mail box . EU .

Found an AKG PU-2R cartridge on an old BSR turntable. I wonder if it's anything of high value, or quality. Thanks.

For Sale: Quad 405-2 amp in clean condition with some surface scratches. I bought it for my Quad ESL-988, but prefer my NCores...

Had a little bit of noise, so I changed C5 cap (as recommended) and now nice and quiet...

Hows $400 + ship or pick up in West Sub of Chicago?

Cleaning out my workshop. This is what I've got, before it goes to eBay.

4 Vifa TC18WG-15-08 7" (Infinity) "buyout" Woofer $40/pair
SOLD *2 Vifa DX25TG-05 Tweeters $50/pair
SOLD *2 Vifa M13MI-08-08 Alnico midrange (Alon) $100/pair
2 PHL 1120 Midrange $200/pair
SOLD *2 Seas Excel W21EX001 Midbass (paper cone/copper phase plug) $200/pair
1 Seas Excel W17EX-C (Pro-Ac) $50
SOLD *5 Seas 27 TDFC/TV Shielded Tweeter $50/pair $100/5
2 Heil Tweeters 10b Panel Mount $100/pair (1 tweeter needs replacement element)
SOLD *2 Heil Tweeters Tempest style panel mount $100/pair
1 B&C 8PS21 $75

Most of these were tested, but not used extensively and have sat in boxes for 15+ years. They may have mounting scuffs on the screw holes or something, but were never used in a design. Heils were used drivers when I bought them. Won't separate pairs, the Seas tweets can go however.

Thanks for looking. If you want a couple things, send me an offer.

Hi,

I am happy to be a part of DIY Audio! This is my first post. Apologize if my posting is not perfect.

I am developing a 2 and 2.1 channel remote controller kit using PT2314 and ATMEGA328. PT2314 is absolutely amazing audio processor with 4 inputs, bass & treble controller and I2C/IIC communication.

The amplifier which I am using for testing purpose is a Class D amplifier which runs in 12V.

When I power up the amplifier and the audio processor circuit with the same power supply and with common ground, the audio processor circuit works fine without issues except for some digital circuit noise.

But when I power up with different power supplies for the audio processor circuit and the amplifier, the PT2314 becomes very hot and fails then on. In this case the the analog and digital ground are isolated. I am not sure if this isolated ground connection creates the problem. But I am sure there is a specific purpose the analog and digital ground are separated by the IC manufacturer.

Please find the pictures attached for the connections made. I sorry for the bad picture.

Anyone please suggest how to make this circuit work with different power supply for amplifier and audio processor / controller circuit.

Thanks,
DMA

Hello,
I've for sale a Terrasonde Audio Toolbox 1, including 230V adapter, in perfect shape and working order.
Here you can find more info:
AudioToolbox.US - Your source for Terrasonde Audio Toolbox.
I'd like to get 150eur+shipping and Paypal fees
Best regards.
Guglielmo

Selling a stereo pair of boutique-grade Black Rhodium Illusion interconnects (phono to phono), 1m long.

My thoughts are: Amazingly balanced bass reproduction with crystal clear trebles. Selling due to surplus of leads (I got rid of a pre-amp stage as my DAC has one built in now).

Review: Black Rhodium Polar Illusion review | TechRadar

Specification:

• Silver-plated Copper conductors for clearer mid and high frequencies.
• Low loss PTFE insulation for tighter control of the sound of bass instruments.
• Conductors are tightly twisted to reduce the effects of RFI and hum.
• Fitted with 24k gold-plated Eichmann Bullet phono plugs for enhanced sound quality.
• Cable pairs are twisted together for extra clarity of sound and improved imagery.
• Black Rhodium Illusion Diva Hifi Gear
• Black Rhodium Illusion DIVA - Zouch Audio
• RRP GBP £200.00

Price:
GBP £99 with free tracked shipping to UK.
GBP £99 with added P&P for non-UK internationals.
(I will only send tracked).

Splitting this into a separate thread from my top cap design thread because it seems more broadly applicable.

This is my first attempt at designing a power supply from scratch. I'm looking to get an OP of about 52mA@350V per side of an 815. That represents 70% of the max plate current and max plate voltage, and hits at about -18V bias on a 460V B+ ... assuming I drew the load line correctly, and that my screen voltage delta doesn't shift things too much.

Spitball on the preamp (not designed yet) is 8mA on a 400V node and 10mA on a 300V node. Those are probably high.

Here's the thought process:

• The PT I have puts out 370-0-370, rectified by a pair of (massively overspecified) 3B28s in full-wave
• Pi filter with 50uF-4H-50uF, feeding 105mA @ 460V
• 3.3k dropping resistor and a 22uF cap, feeding 8mA @ 400V
• 10k dropping resistor and another 22uF cap, feeding 10mA @ 300V

PSUD2 says this will work. I know I'll have to tweak values as I work out the rest of the circuit, but does this seem like a sane starting point? What have I messed up? What can I improve?

(Note - the 50uFs are really 100+100 to handle the voltage.)

Good evening, I am a new member from Italy, my name is Emiliano, I wanted to make an Aleph 5 finale but I have problems finding mosfets, can you give me equivalents and articles where we talk about this realization?
Thanks in advance.

Patient: Marantz 7200 (Class A+AB), 20 yrs old
Symptom: annoying hum
Investigations results: filtering caps should be replaced
Debate: I have the possibility to replace old 12mF caps with 33 or even 47mF caps. Do you anticipate any problems if I will do so?

I'm having a bit of a cull of the projects I've enthusiastically collected but, realistically, will never get around to progressing, so a few bits and pieces people might find useful or interesting (or maybe both?).

1. Set of PCBs to build a Hiraga 'La Monstre' 8wpc Class A amp. I bought these from member 'sachu888' here on DIY Audio. Just the bare boards except that I've soldered a set of (genuine, purchased from Spencer) 2SJ74/2SK170 FETs. PSU boards are a cap multiplier. I have a BOM and the PCBs are well labelled. 'La Monstre' schematics etc. are available on the long thread here on DIY Audio. There are some build pictures here (look for member sachu888) https://www.diyaudio.com/forums/solid-state/5462-hiraga-le-monstre-132.html

£10 plus shipping and PayPal fee at cost.



2. TentLabs E Choke. Never been near a power source! Info here - Electronic Choke

£20 plus shipping and PayPal fee at cost.



3. K&K Audio Time delay/soft start board. Assembled but never powered up. Info here; Other kits – K & K Audio (about 3/4 way down)



£15 plus shipping and PayPal fee at cost

4. I got a bit enthusiastic about building a Tim Mellow OTL amp using the Ares Audio PCBs

OTL Power amplifier - ARESAUDIO electronics & audio engineering

but I've decided I can't justify yet another amplifier project so have to offer a set of boards, consisting of 2 x input/driver PCBs, 1 x Power Supply PCB and 1 x Soft Start/Protection PCB (including the microprocessor). The boards cost me 60Euros.

£28 plus shipping and PayPal fee at cost - I'll throw in 6 x 9pin tube sockets too.



Send me a PM if anything is of interest. Happy to post just about anywhere. I have some more stuff that I'll post in the next day or so.

I have a vifa d25ag xx metal dome tweeter which sounds very airy when starts playing, but in 2-3 minutes the treble becomes muddy. More vocals starts coming up through it. If I slightly pushed the tweeter it becomes more airy and less vocals starts coming up through it. Is the tweeter suspension became bad that it cannot pull back the vibrating tweeter ? But funny thing is , if i turn off the speaker for some time and then again turn on, it’s alive again for 2 minutes. I contacted the manufacturer and he mentioned the inductor parallel to the tweeter could be bad.


I am not convinced that a inductor can ever go bad. After all it’s a much thicker coil and how would it degrade ?

Has anyone tried? I've searched around a bit and realized that nobody seems to have really discussed this.

There are thermal advantages and it could reduce thermal noise by keeping components cooler. But I think it's more of an interesting conversation piece to be honest.

This has been in practice for 10 or 20 years on the custom PC side. As far as I know nothing dissolves or adversely affected. They submerge everything. The motherboard, GPU, PSU, and memory. Except for disc hard drives. Mineral oil is non-conductive and non-flammable.

The drawbacks...

- Laws of thermodynamics still apply. The oil will heat up over time and there's a requirement to get rid of that heat.

- It's messy.

- Possibility of leaks.

- Weight... But I don't think most of us move an amp after setting it down.

Ok, I punched numbers in (online calculator) for a w8-2145 with a 4mh baffle step coil (1.24 ohms).

The Qts goes up from .45 to .495

For a sealed qtc .707 box.
Vb goes up from 1.63ft3 to 2.3ft3
F3 = fsb = 63hz goes down to 57hz (audible ? probably not)

Ported (standard 4th)
Vb goes from 3.43ft3 to 4.7ft3
Tuning goes from 35.7hz to 32.5hz
F3 goes from 34.13hz to 29hz


I assume (yup, I know the saying, but got to try), use the new numbers for ideal box size ?

I'm starting to design my first speakers, using DSP for crossovers instead of analog.
I've been reading the "Designing crossovers without measurements" thread and I'm trying to pick up as much as I can from it, but I'm wondering which parts apply when not building analog crossovers but using DSP for crossovers instead.
I'll probably be able to apply most of what I learn, but still - is there an equivalent article that could help me that's aimed at using DSP instead of building analog?

For sale is an enclosed Oatley Electronics K272 hybrid tube amplifier. This was built from a kit and uses two 6418 subminiature vacuum tubes as a preamp and an NE5532 op amp as the power stage. It is powered by 3 AAA batteries to power the filaments of the tubes and 2 9V batteries to power the opamp as well as the plates and screen grids of the tubes. Battery life is excellent.

I built this amplifier myself and it works very nice, is very quiet and has plenty of power to drive both my MDR-V6's as well as my Sennheiser HD600's. It is enclosed in a Hammond extruded aluminum case. Batteries are not included.

I would like $100 plus shipping for this amplifier.

Images:

https://images2.imgbox.com/8b/38/U4jVU7yI_o.jpg

https://images2.imgbox.com/67/24/DgM0f1AB_o.jpg

Hello folks,
i've been throwing parties for a while now with friends, in the city or in the countryside.
Til that point we've been renting our sound and got a really good deal on a nice l-acoutics system that can be scaled up or down depending on the expected crowd. So we've been getting good sound, but still, been interested in the history of discos, club, soundsystem and had a few experiences of hi-fi club sound (lucky cloud and beauty & the beat - both mancuso / loft inspired parties with khorns) and besides owning (which add its own set of challenges like storing, maintenance etc), i guess what draws me towards building a soundsystem is hi-fi sound, and also it's a bit more sexy to throw parties with your custom hi fi system (if you paint it right) rather than rented black boxes.

Anyway, i'm not a technical person, and despite having read lots of threads here and elsewhere there is still so much i don't know.

For the moment my mind is set on building a 4 way stereo system : so one tweeter, one horn for highs, one cabinet with two woofers for low mid / bass, and two subs by side.

I'm looking at building it gradually because $$$, so not in one go and i'd be starting by the highs / bass sections, before subs, then getting tweeters.

For the highs, i'm looking at the Radian 950pb, which combined with a a tad th4001 (clone, available on ebay & the web) seems like a nice pairing.

For the low mid / bass, i'm looking at building myself an Altec 817 cabinet, with 515 gpa drivers, so 2 drivers each side.

For the sub, i'm looking at making Lab subs (4 of them) (designed by tom danley) with 12inch speakers in it.

I guess, building the altec cabinet and the lab subs is one thing and a challenge in itself with my mininum woodworking skills (but i'd be getting help), but what i'm not really sure about is the coherence of the system as a whole, if each section in relation to the other is right in terms of frequency overlap, crossover etc.

obviously i'd be getting active crossovers, but i'm not sure about those, which i should be getting. For getting the xovers frequency right i'm lucky to be friend with two talended sound engineers, so they'd be helping on that side.

I'd like to know your thoughts on getting started on such a project, if my genereal idea of a system is valid.

thanks

Hi guys: I tried this question on PC forums but they were clueless, I figure this might be a better forum.

I am trying to switch my power amps on (they run my PC speakers) when the PC wakes up. I am currently turning them off/ on manually and whats the fun in that.

I have a solid state relay that can switch 120vac-240vac (I think) with a DC input of 3vdc to 24vdc.

Question is how do i feel voltage to the relay that is dependant on the PC's wake state.

I could run a loop from the PSU's 3, 5 or 12v lines I guess to trigger the relay, but am fearing cross contamination of HF from the PC's switching PSU going into the Solid state relay and finding its way into my analog power amps.

Whats an easy way to accomplish this?

Hello,

I have a complicated system of 2 Amps plus DSP unit and want to "downsize", and btw. change over to new speakers (yet to be defined - I am thinking of 4 x 15" passive subs plus 2 good affordable and light-weight 2 or 3 way passives).

In order to get best possible sound quality, is it possible to circumvent ANY conversion to analog between the servers of Spotify and the Amp's DSP by going Dante over Network cable from PC to amp. I don't need any mixer / mike etc. Can speak to the crowd via megaphone. Are there any pitfalls to watch for?

The system would consist of PC, network cable, 1 u amp and 4 or 6 speakers ( plus cellphone to get internet access of course). the whole system (Laptop, amp and cellphone charger would run on 1 x 230VAC / 16A distributor that can be bought for about EUR 3.49.

I 'd carry 2 or 4 15"-subs to the party depending on power requirements. (16 Ohms in bridge mode on 2 channels or 8 Ohms in bridge-mode. It is important to bridge the sub channels or phase-invert one of the sub amp channels if they are only half bridges - compensating the inversion by reversing the speaker wires of course - in order to go the "powersoft digi-mod way" of "balanced supply mode").

I am thinking of something like T604. This thing is quite expensive. Are there any similar lower-cost alternatives? Total system cost excluding laptop should be <=6K EUR. Maybe 7K if I am REALLY satisfied. (10K if I am lucky at the lottery) 😉

Then there is just the right kind at meniscus audio, Eclipse W6520R-8 currently selling for $41.82. Got the TSP almost like the vintage Dynaudio 17W75.

Greetings All. Eric here, newbie, been playing bass since 1982. I have what I originally thought was going to be an easy question to answer, and yet, despite the fact that I have posted in several different audio forums, and sent numerous emails, no one seems to be able to give me a straight answer. So it with great hope that I post this to all of you, my new DIY brethren. Allow me to set the scene.

I own a bass 2x15 cabinet.
Each speaker is a 400-watt Carvin PS15, rated at 8 ohms/400 watts each.
The 15's are wired in parallel for a total impedance of 4 ohms.
My amp is a Crown XLS1000 Drivecore that makes 350 watts into 4 ohms.

My question, given all of the above parameters, is this:

How do I add a higher-frequency driver and/or tweeter?

I have been getting piecemeal answers about things related to how it's done, but no one has been able to spell it out for me. I have spent hours scouring the web for the answer, but all I got was a major headache.

Can any of You help me please?

Hello everyone,

I'm designing stage microphone preamp with effect loop for a friend based at THAT 1510 & 1646 (or maybe INA217 & DRV135).
XLR microphone input, unbalanced send / return and XLR line output.
But I still can't decide how to handle power supply.

Usually I would use cheap wall-wart style AC transformer with half wave rectifier and LM7815/LM7915 regulators for +/- 15V rails. In my experience this proven to be simple, cheap and low noise.

However, requirement of phantom +48V makes things much more complex.
Basically I want to get internal +15V, -15V and +48V from single, standard and convenient wall wart style supply like 12V DC, 15V AC or 48V DC.

Boost converter from 15V to 48V? This potentially could introduce some imbalance to rails which isn't best thing with half wave rectifier.
With external +48V PSU it is straightforward to get phantom. But what about powering op amps? Maybe some kind of virtual earth rail-splitter? +/- 24V would be too high so voltages still need to be regulated. Single IC split-rail switching converters are expensive, complex and usually works only with low voltages like 5V.

It needs to be rather compact as I want to fit everything inside Hammond 1590BB. I don't want to make it overcomplicated, while keeping limited PCB space and low cost in mind.

I'd be grateful if anyone can suggest me some clever solution.

Hi All.
I'm running a raspberry pi 3b with a hifiberry DAC plus pro hat. I've isolated the DAC from the power of the RPi and am now running it from a linear power supply fed through a mains conditioner. I'm now really happy with the sound for its price (not sure if the mains conditioner does much tbh). Is there any mileage in feeding the RPi from a linear psu or can I leave that dirty? Also, I'm assuming there's an opamp on the DAC. Is it any good or could I bypass it and run it into my Lampizator buffer?

hi, what are some current feedback opamps such as ad844 846?

Thanks in advance

1) A rare pair of Raytheon CK 7729 gold pin vacuum tubes. These tubes are a low noise, low microphonics industrial version produced for critical applications such as aviation. These very rarely come up for sale. These tubes were made by Raytheon as designated by the "280" EIA code. They also have the same date code of "63-17" which corresponds to the 17th week of 1963. These tubes have been tested for shorts, grid leakage and emission on a restored and calibrated Sencore TC-142. The results are as follows:

Shorts: PASS
Grid Leakage: PASS
Emission:
Tube 1: Triode 1: 99% Triode 2: 99%
Tube 2: Triode 1: 99% Triode 2: 99%

In addition these tubes have had a life test performed on it which entails reducing the filament voltage of the tube under test by one step and noting any significant reduction in emission performance. Both triodes of both tubes performed excellently.

I would like $175 plus shipping for these tubes.

2) A trio of 6679 12AT7 tubes manufactured by RCA. The 6679 tube was originally manufactured for mobile communication and maintain output even with variations of filament voltage. They are equivalent to a 12AT7 tubes. These tubes have square getters and all three have the date code of "6122" which equates to the 22nd week of 1961. These tubes have been tested for shorts, grid leakage and emission on a restored and calibrated Sencore TC-142. The results are as follows:

Shorts: PASS
Grid Leakage: PASS
Emission:
Tube 1: Triode 1: 102% Triode 2: 103%
Tube 2: Triode 1: 102% Triode 2: 102%
Tube 3: Triode 1: 102% Triode 2: 102%

In addition these tubes have had a life test performed on it which entails reducing the filament voltage of the tube under test by one step and noting any significant reduction in emission performance. Both triodes of all three tubes performed excellently.

I would like $40 plus shipping for these tubes.


3) A pair of General Electric 12AY7 tubes. These tubes have angled square getters and grey plates. They have been tested for shorts, grid leakage and emission on a restored and calibrated Sencore TC-142. The results are as follows:

Shorts: PASS
Grid Leakage: PASS
Emission:
Tube 1: Triode 1: 95% Triode 2: 94%
Tube 2: Triode 1: 95% Triode 2: 95%

In addition these tubes have had a life test performed on it which entails reducing the filament voltage of the tube under test by one step and noting any significant reduction in emission performance. Both triodes of both tubes performed excellently.

I would like $35 plus shipping for these tubes.


4) A Mullard ECC81 12AT7 vacuum tube. This tube has a square getter and has the code sequence Tk1 B8F with the "B" signifying the Blackburn, England Mullard plant where this tube was produced. This tube has been tested for shorts, grid leakage and emission on a restored and calibrated Sencore TC-142. The results are as follows:

Shorts: PASS
Grid Leakage: PASS
Emission:
Tube 1: Triode 1: 100% Triode 2: 99%

In addition this tube has had a life test performed on it which entails reducing the filament voltage of the tube under test by one step and noting any significant reduction in emission performance. Both triodes of the tube performed excellently.

I would like $20 plus shipping for this tube.

Eminence New N314X-8 Compression Driver Leads the Way with Textreme Diaphragm | audioXpress

N314X-8 - Drivers | Eminence Speaker

Hello everyone,

I am a new member to the forum - just registered today.

I have a Heathkit A-7D Audio Amp I just purchased and I understand that there are some modifications that have been made to it over the years. Would anyone in the forum have any knowledge as to where I can find those mod's. Thank you, I would appreciate it.

Bill
KI7ZAD

Hello and happy new year everyone! Long time reader, first time poster. Over a decade of reading, love the forum.

I am in the planning stages of what I think is considered a simple 2.0 setup for my office/gaming/computer room. But it may actually be a 2.2 setup, I'm not sure.

I am looking to have 2 smallish to medium sized towers, on each side of my desk, so I can relax and and listen to music/videos and such without having my headphones on.

For practice purposes I would like to make each speaker box a 4 stage unit, with an active crossover setup. Tweeter, highs, mid, low, sub. I realize that is completely unnecessary, but I would like to try and do it, again, for practice and a challenge. I am hoping to get some practice so I can successfully upgrade our current projector/movie room's audio setup past the auto-configuration in the receiver. 😛

My question to this part of the forum is, what hardware and software will I need to do this? I have been doing some research but have a hard time finding the correct terms to get good results. My main computer is a Windows PC, but I have extra computers available if it is recommended I made a dedicated Windows or Linux box specifically for the speakers.

What I have found so far is:
Hardware-
USB Sound card : https://www.amazon.com/StarTech-com-7-1-USB-Sound-Card/dp/B002LM0U2S
I am concerned that is will be low quality?
Maybe a PCIE sound card if that will help? Like this one? : https://www.amazon.com/Creative-Blaster-Audigy-Performance-Headphone/dp/B00EO6X7PG/

Amplifier: I have been looking for an 8 channel amplifier, but have only been able to find this 12: Dayton Audio MA1240a Multi-Zone 12 Channel Amplifier

Cables: 4 of these 3.5 MM to RCA https://www.amazon.com/AmazonBasics-3-5mm-2-Male-Adapter-Stereo/dp/B01D5H8JW0

Microphone : miniDSP UMIK-1 Omni-directional USB Measurement Calibrated Microphone

Software: REW and Peace equalizer? Is that really all that is needed?

Other than the speaker wire and the speakers themselves, is this all I need hardware wise to complete the project? Do you have any other recommendations?

Thank you.

hi,

i'm looking for a schematic diagram for a guitar/keboard amp with leslie speaker.. mainly the Power amp section.

on switching on the rail fuse blows and a huge humm is heard ,,

also r23 is burnt and a 100ohm is burnt too..

thanks any help will be appreciated.

I have built an Tabaq-like MLTL with Dayton PS95-8. The internal box volume is ~9.5 L, current port length 80mm, diameter 36mm. It is simple round port, the speaker box is shelf type and used as a shelf type, so no bass augmentation from the floor is needed/used.

I want to remake the box and due to the specific folding, I cannot use 80mm length port, so I need something shorter, also I cannot use the variable length tubes I like so much. According to http://www.p10hifi.net/FAL/downloads/ChangingPortSize.pdf I recalculated, that if I chose port length ~71mm, its diameter will be 32mm.


The Sd of the PS95 is 28.3cm2, the original port cross section is ~10.2cm2, so a bit more than 1/3, ~35% Sd. The new port cross section is ~8cm2, which is right between 1/3 and 1/4, ~28% Sd of the driver.


Listening levels are smth from "personal" to "movie" but far from"party". With the original 36mm diameter vent I hear no sound artifacts because of port turbulence. It just sounds OK for me. If the sound level is bigger, it feels that the driver is approaching its limits faster than the port.



The question: will the same internal volume (and MLTL line length) box with the new smaller port be OK or the port is simply too small?


Thank you.

Hi all,

Saw a good deal on some Ruark speakers, was very happy with the great price I'd got, got them out of the car, picked on up by the rear port, plastic insert slipped out and the front of the speaker smashed on the tarmac. Luckily most of the speaker was saved by the proud cap head screws. Now the cabinets were a bit tatty anyway and I saw them as a bit of a project anyway so wasn't hugely bothered.

However, put them on and found the mid/bass woofer doesnt work... that is an issue.

It seems from my experimenting that the voice coil has come away from the diaphragm and from calling about fixing this isn't something many people are willing to attempt anymore. Unfortunately its a 6ohm driver and as a result replacements aren't exactly easy.

I found someone who actually would like to buy the other driver and since it looks like finding my own spare is next to impossible Im thinking it would be a good idea to cut my losses and sell it leaving me with 2 tweeters and a cab with a crossover which isn't exactly all that useful.

Useful info:

• The tweeter is marked as: Ruark Solus MDT 25S by Morel (believe hifi collective actually sell this.
• The driver in question is: Vifa M18WO-09 (6 ohm version) (falcon acoustics actually sell the 8ohm version but its not cheap)
• The enclosure is the Ruark CL20, seems well made, dimensions are 300x300x930 mm with a slight lean back and an interesting sort of curved mdf bracing around the outside but only on the section with the speakers installed

So my question is:

1. Is it realistic to be able to find a replacement driver?

2. If not, would someone have any thoughts on what driver would go well with the tweeter already in place? Then I obviously need to make a new crossover to suit, where is a good place for reading material in order learn how to do this?

I'm design engineer by trade so maths and mechanical stuff is a strong point of mine, however i always hated the electronics part of university.

Hi!

I'm a new forum user. I signed up to ask for advice on the construction of my amplifier.

I got a Sure AA-AB31314 amp board and a Mean Well RSP-500-48 PSU.

In order to protect my speakers I want to create a circuit to avoid spikes during turn off/on (I don't want to modify the amp because of warranty).

I found timed relays to decouple the speakers during power up but ... the idea of ​​passing the amplified signal inside a relay does not excite me at all.

So, I thought of an alternative circuit, but since I'm not too expert in electronics, I need a help...
I am thinking of connecting the positive pole that goes to each speaker to ground, through a relay that is closed during the power on and the power off (without music playing) and open with music playing (in this way the power signal does not pass through the relay).
Leaving aside the way in which I control it (which is not a problem with an Arduino type controller) I would like to know if this circuit can actually avoid overvoltage peaks to the speakers, or if it's idiocy ... 😛

I thank in advance anyone who wants to help me.

So, I have gorged much and digested some of the mind-numbing multitude of threads contained herein of deep knowledge, analyses and quibbles on varied DIY audio subject matter.

In doing so, I've realized that, on this forum, getting a simple answer without a dense paragraph of caveats or without a pre-ambled sound measurement hypothesis - is as difficult as understanding why some people don't like anything Star Trek or why others actually like to eat candied fruit cake.
Nevertheless, I will pose a simple question, hoping for a few reasonably simple answers to help with my first speaker build, and ultimately to achieve enlightenment within this realm.

Q: For those who have experienced and believe that a good compression driver & horn/waveguide combo delivers an overall more dynamic midrange-to-high frequency sound experience (vs. dome tweeter or dome tweeter & midrange cone), what is your vote for a specific model of horn/waveguide that delivers the least 'sound colouration'? I ask this because I have been reading many conflicting opinions about which horns do or don't add colouration. And nevermind discussing other variables like room acoustics, audio gear, on/off axis directivity, crossover design, etc., which really shouldn't affect horn colouration.

Thanks, music lovers.

Hi all,

So I'm NEW to building electronics - so thanks in advance for your patience with me haha.

I bought this with the 2.5" heatsink option and 12vdc output.

I rolled up the voltage from 0-18vac and cannot get a clean 12vdc output voltage on it. What am I missing here?

Here's a photo off the scope:

Bought myself two pcb-s of JHL 1969 some years ago. This summer I want to finish the amp, and I will use a Switch Mode PS with 27volts. When I am adjusting the pot.meters, R1 and R7, how do I do that? I have lost all the documentation I got from the seller, but I think that R1 (100K) shall be adjust till I get half the voltage, 13,5volts, between one end of C4 and input ground?, is that right?
R7, 1K, I do not have the clue what to do with? The pcb have the text "www.diyhifishop.com"

I have a pair of these speakers in excellent condition (externally at least). They have been stored In a closet in my air conditioned house for about 5 years. I plugged one in today. I let it charge for an hour or so. Using QUAD 405 amp. Speaker plays but much bass output. How long would one expect the panels to fully charge so I can determine if they work well or not? Very wet and humid today although speakers in air conditioned house if that makes a difference.

Thanks

Hi to all. I'm looking for help in designing a crossover network for a semi clone Tarkus built according to the design of The Tarkus by Paul Carmody. Why semi clone , simply because I am using Tweeter ScanSpeak Discovery tweeter D2608/9130, midrange from Monacor MS130 and Peerless woofer P830668 as used on the original design. All the drivers are fully burnt in. The enclosures are built on the original plan, but following a cut out error the bass bin is slightly bigger 64 L instead of 62. I am somewhat weak in xover design , but I am conversant with REW as regards measurements, I have a Uphoria UMC22 sound card and behringer ECM8000 microphone. My next post will provide the drivers' raw measurements following these questions:-

My 1st question : Is it ok to measure the drivers farfield at 1 meter or at listening position which is approx 2m50?
My 2nd question: Is it ok to measure all the drivers at tweeter height?
As for the woofer, I am not conversant with merging nearfield, farfield and port, although I have gone through ARTA explanations. personally I find it complicated in Arta to get a merged file. I have also tried to use Jeff Bagby xls which run really too slow and lags drastically on my computer. So any help from users will be appreciated. Enclosed photo of Semi clone Tarkus waiting for xover.

Hi,

Watt Puppy Clone using:

1 x Focal TC120
1 x Scan-Speaker 18W8545
2 x Peerless PPB 831868

Cabinet Overview
http://img170.imageshack.us/img170/803/cabge6.gif

Tweeter and Midrange Crossover
http://img211.imageshack.us/img211/3308/woofervo1.gif

Woofer Crossover
http://img98.imageshack.us/img98/4876/tweetermidiy6.gif

Dimensions:
Tweeter/mid - http://img223.imageshack.us/img223/3272/cab2ro5.gif
Woofer - HxWxD - 574mm X 257mm x 420mm
-The Port is of 75mm inner diameter and about 200mm long

What you think?

Any advice on the woofer enclosure?

Up for sale: I have fourteen pairs of brand-new-in-box Mark Audio (Markaudio) CHP-70 Gen.2 wideband drive units with the charcoal black paper cone. I mentioned these in my charcoal / black colour cone CHP sale thread here: FS Mark Audio (Markaudio) CHP-70 Gen.2 drive units (charcoal black cone) They are the same unit, the only difference being the black / charcoal colour cone.

For background interest the CHP-70 Gen.2 was developed by Markaudio in conjunction with their Japanese distributor and a number of his jazz / small club playing and listening enthusiasts. Their object was to create a 4in wideband driver with a semi 'vintage tone' that captured some of the characteristics of classic wideband units, with a lightly shelved down top end and smooth / natural midrange tone. Between the original unit and the gen.2 MA changed its graphing scales &c.: the drivers actually have similar responses, but the Gen.2 models introduced a raft of upgrades: an improved basket, a new central cap, Japanese designed low-mass coil and a new spider design providing a 12% reduction in moving mass.

Main CHP-70 Gen. 2 features:
-Usual Markaudio shallow-profile cone for consistent off-axis response
-Reinforced self-damping polymer basket
-Long-throw suspension
-Well balanced Fs, Qt, Vas to suit different types of load (works well in sealed, vented, horn & QW -two examples below in resistive vent marKen standmounts, and used as wideband midbass drivers in a pair of compact floorstanders)
-Black (charcoal colour) paper cone
-Supplied with factory gaskets and connecting hardware

I'm asking £30 per pair plus shipping (less than half normal retail)

All drivers are packaged in their original Markaudio boxes. I use sustainable FSC rated outer cardboard boxes fastened with heavy-duty packing tape. These are reinforced inside with recycled heavy-duty cardboard and packed with recycled brown / grey packing paper and high quality bubble-insulation.

Thanks as always for looking, and if you have any questions, please don't hesitate to ask.

Anyone have a picture of the areas in front of both regulators ?

R215 is burnt

R473,477 begins rca jacks are also burnt

Trying to build a 1st order low pass filter and the calculators I have been trying to use all give me a way low turn count . I have given the info asked for input ,but still get a non-sense answer.... Mild steel core 1" in diameter x 1" long , wire size .031 , mild steel has a relative permeability of 2000 .....,
Shooting for 12.8 mH and another one 4.2 mH ( same core size ect.) Please help me.

Hello,
I've for sale an SDTrans192 board in perfect working order, with the PPS caps modification suggested by Bunpei. Asking €. 150 plus shipping and paypal fee

Hello

Haven't been working with amps for years but a friend asked me to look at his Hertz EP1D.

Amp's relay does not engage, DC protection kicks in, that means that protection light is not on but the relay is not engaging. Relay is in working order. I checked by applying 12V to its appropriate terminals. Tried to measure voltage on the transistor supplying 12V to the relay while amp was running, when measuring the relay engages, DC on speaker terminals on that moment was 0,5V. Tried playing music through speaker while holding relay open, plays fine, no excessive heating. While relay is not engaged before the relay there is good audio signal, it is just not getting through the relay.

Anyone got a clue what could be causing this problem?

Dayton Audio PSS555-8 21" Pro Subwoofer with 4.5” Voice Coil 8 Ohm
Too bad shipping to Oz costs so much because it looks like a good candidate for bragging rights boxes

First of all sorry if the thread is in wrong section
2ndly, hello i am new here . First post
Now, on topic,
I just happen to find a really old 8Ohm 75RMS phillips subwoofer lying around.

i have the sub only, nothing else.
Currently i am running this thing with a cheap tpa3116d2 board

Running with a 24v PSU. But if i am not wrong i am getting max (24x.6x24x.6)/8 = 26w RMS
i want a cheap amp which can drive it to the max potential.
I can have 36v PSU but strictly DC.

I have a Belva BB3000D V2 class d amplifier. The amplifier will play audio ok, but goes into protect at higher volumes. I do not have very much experience with Class D Amplifiers. I was unable to get a schematic from Belva. What should I be looking for. Any help would be great, thanks.


Isaac

Where do most guys buy their power transformers?
I need 6.3Vac and about 250Vac, but only at a total of about 100mA for the HV secondary. Very hard to find in Oz.......

HD

Hi everyone, been away for a while, and am now in the market for a new digital streamer. The Bluesound Node 2i seems a great choice and almost pulled the trigger on it last night. VERY highly rated by customers and a What Hi Fi? 5 star review... then I checked the reviews on the BluOS app (the app which of course controls the node 2i)... DISASTER. A complete 180 departure into 1 star catastrophic oblivion is what came up. LOTS of very negative reviews.

I DON'T GET IT?! Can someone with experience with this device please chime in? Is this a screaming deal or frustrating disaster? Totally can't understand how something can be so highly regarded while its own control mechanism derided as so terrible???

Wild Burro Betsy pair in near new condition. $110 shipped lower 48 usa.


Hemp Acoustic 8's. One pair. Function fine. But cones are faded. Whizzers detached, and creased, not sure could be reused. $90 shipped lower 48 usa.

I changed the ad a couple times when I wasnt getting any rexponse. Am a bit scattered with excess work these days. Sorry. Ill keep it like this.

Thanks, Don

Hi!

I'm starting the design of my DAC/AMP based on the PCM2903C (for the dac), and the amp part based in the Objective 2. I'm doing this more with the purpose of learning than actually getting a super good dac/amp.

I'm not an expert so I thought that a good place to start would be a product made by, well, experts. So I download the datasheet of the PCM2903C evaluation board and saw that they placed an OPA2353 active low pass filter in the output.

While wandering around in the TI website I saw a equivalent model to the OPA2353, that seems to be better spec'd, while costing the same in Mouser, the OPA2365.

Questions were raised when I noticed that the OPA2353 datasheet stated that it is unity-gain stable, leading me to the thought that it makes some sense, since the active filters should be (inside a desired range of Hz) unity gain stable, right?


On the other hand, the OPA2365 does not claim such a thing, and furthermore, it recommends having a pulldown resistor in the output, connected to an additional negative supply when operating as a buffer, even though, said resistor is not included when the OPA2365 is acting as an active filter.



My questions is then, can the OPA2365 act as a LPF without the pulldown resistor without deteriorating the performance of my DAC? It seems to be an direct improvement of the OPA2353, while costing the same.

Or should I be using an different op amp as a LPF? Do you guys recommend any?

Thank you for your time!

I am looking for a commercial single ended to balanced line out converter or preamp stage. Pre-made units boxed and ready to go don’t seem to be readily available. It seems like a basic thing but not sure why something for say $40 from Behringer or similar doesn’t immediately come up on a search. However, a $10 Sparkfun THAT1646 breakout board with TRS jack did come up. If anyone has suggestions for a commercially made ready to use one, please share here:

Sparkfun THAT1646 breakout board:
https://www.digikey.com/products/en?mpart=BOB-14003&v=1568

Needs a +/-voltage PSU and a panel jack.

I have made simple 2 transistor converters using a CFP in SE Class A and that works well but looking for an ultra low distortion IC implementation here.

I decided to Marie Kondo my lab. I haven't touched tube circuits in years, so my collection of tubes, sockets, high-voltage caps, etc. no longer brings me joy. I think it's time for them to bring someone else joy. 🙂

If you're interested in buying, please toss me a PM or email (add @neurochrome.com to my user ID here). I take payment by credit card directly or by PayPal. Credit card is preferred.

I will use strikethrough and (PENDING) to indicate that a buyer has expressed interest and requested a shipping quote. I will use (SOLD) to indicate when an item has sold.

Unless otherwise noted all tubes are used but not abused.

I will be selling them at the quantities listed.

I'm happy to work out a deal for someone who buys all of it (or all of what's left).

I ship from Calgary, Canada by Canada Post (or DHL if you want it faster and are willing to pay more). I have commercial accounts with both and get a pretty nice discount, which I will pass on to you.
I'll have to quote shipping for each order, but expect shipping to run about $15-20 to the US and $19-25 for the rest of the world (including Canada). If you buy all the iron, the shipping will run a little more.

I'll take $40 (including shipping within North America) for what's left.

--- TUBES ---

• 6AN4 (QTY 5) - $10
• 6AN5 (QTY 4) - $10
• 6080WA, three - $10 (SOLD)
• 6BY5GA, two - $5 (SOLD)
• RTC E188CC, pair - $100 (SOLD)
• Pinnacle 6J5GT, NOS in original boxes, four quads - $25 per quad or $80 for all 16 tubes. (SOLD)
• Electroharmonix 12BH7A, matched pair - $15 (SOLD)
• Sweep tubes: 6GF7A (x3), 6LU8, 6KY8A (x4) - $5 (SOLD)
• Amperex 5842, pair - $30 (SOLD)
• GE 6SN7 side getter, matched pair - $40 (SOLD)
• 7721 (= d3A), quad - $25 (SOLD)
• Sovtek 5AR4, trio, new in box - $30 (SOLD)
• Tube goodie bag: 6AN8, 6AN5, 6BK7B, 6CL6 (x2), 12AT7 (x2), 6BX7 (x2), 6DW4 (x2) - $15 (SOLD)
• Voltage regulator tubes: 0A3, 0B3, 0C3. Boxes are pretty ratty (except the 0C3, which has a nice JAN box) - $5 for all three. (SOLD)

--- MISCELLANEA ---

• STE 8-3 IEC mains inlet filters. Brand new. 115/230 V, 3 A. (QTY 5) - $3 each or $10 for all five. See Post #9 for picture and data sheet.(SOLD)SOLD[/color]
• Sockets: Various 7, 8, 9, and 12 pin ceramic sockets both for chassis and PCB mount. Most are new. Some have been used for prototyping. About 1.5 lb (750 g) in all. - $10 (SOLD)
• Turret strips (as shown) - $5 (SOLD)

--- FREEBEES (WITH ORDER) ---

• 10 uF, 450 V. Bag of about 30. New.(SOLD)SOLD[/color]
• 100 ohm, 1 W, 5 % resistors (QTY 80) - new (SOLD)SOLD[/color]
• 220 uF, 400 V, 105 ºC Panasonic electrolytic. 10 mm snap-in types. (QTY 2) - new. (SOLD)
• 470 uF, 400 V, 105 ºC Nichicon electrolytic caps (QTY 4) - two used, two new (SOLD)
• 47 uF, 500 V, 85 ºC Nichicon electrolytic caps (QTY 6) - used for prototyping (SOLD)

Select your freebee by ordering at least one of my other items and asking for one of the three freebees listed. One freebee per customer.

--- ELECTROLYTIC CAPS ---

• 1000 uF, 50 V, Nichicon Muse KZ (QTY 16) - new - $10 (SOLD)
• 100 uF, 100 V Nichicon Muse KZ (QTY 18) - new - $10 (SOLD)

--- IRON ---

• Antek AS-4T430. Two windings of 0-70-430 V @ 460 mA, two windings of 6.3 V @ 4 A. 400 VA total. Used for prototyping, leads uncut. - $20 - See Post #8 for shipping charges. (SOLD)
• Electra-Print #8037: 70 H, 20 mA plate choke / inductor, (QTY 4) - $60/pair; $100 for all four. Used for prototyping, leads uncut. (SOLD)
• Hammond 156R: 1.5 H, 200 mA inductor, (QTY 1) - $5. Used for prototyping, leads uncut. (SOLD)
• Triad C-14X: 6 H, 200 mA choke / inductor (QTY 1), new in box. - $5 (SOLD)
• Triad FP230-50: 230 VCT @ 50 mA, 12 VA transformer, new in box. - $5 (SOLD)

--- POTENTIOMETERS ---

• ALPS motorized pot, 50 kΩ, audio taper, stereo (QTY 4) - $10/each or $20 for all four (SOLD)

--- FILM CAPACITORS ---

• 47 uF, 630 V Solen polypropylene caps (QTY 4) - two new, two have been used in prototyping, never cut (or even un-bent) the pins - $25/pair or $40 for all four (SOLD)

• 2.2 uF, 630 V Solen polypropylene caps (QTY 4) - two new, two have been used in prototyping, one has cut pins
• 220 nF, 630 V Solen polypropylene caps (QTY 8) - most are new, some have been used for prototyping.
• 100 nF, 630 V, polypropylene Epcos P/N: B32652A6104J (QTY 4) - new
• 0.1 uF, 630 V polyester cap Panasonic ECQ-E6104KF (QTY 30) - new
• 1.0 uF, 630 V polypropylene Epcos P/N: B32674B6105K (QTY 6) - new
• All 52 caps on this list: $10

• (SOLD)

Thank you tubes... 🙂

Tom

Hello everyone, I'm trying to do my first project with DIY Audio. I have found a old radio in the shed, a big wooden box from GDR times.
After checking it it did not seem to work and there are not that many circuit diagrams for that exact model so I figured I would try converting it into a bluetooth speaker (not a portable one but still).
I found this youtube video of someone building a 2.1 bluetooth speaker and thought that I might be able to pull that off: YouTube
I wanted to maybe change it up a little bit as some parts would be easier for me to aquire, the whole voltmeter part would also be left out because it does not fit the aesthetic of the old radio.

I now have some questions for parts and compatibility. I wanted to go for a "Class D" amplifier: TPA3116 2.1 Klasse D Digital Verstarkerplatine Amplifier Board 100W + 2x50W DE | eBay. It has 2x50W and 1x100W output. I also wanted to use crossovers: 2-Stuck V-150 2 Wege Frequenzweiche Crossover Weiche 150W 4-8Ohm 3-3,8kHz 12dB | eBay (sorry that all components are from german ebay).

As I am really completely new to this: first question: would the amplifier and crossovers be able to work in this configuration? Also: what should I look for when looking for drivers for this setup.

My second question for that matter would be how to arrange the insides of the speaker or is that information given in some way in the specifications for a driver. Maybe it isnt really necessary, I dont want to have the utmost high quality sound.

The bluetooth receiver part shouldn't be to hard to pull off. But I would like to add one last thing: a kind of "pre-amp" (?). I don't know the terminology but to describe what I want to achieve: I know that there are adjustable equalizer pre-amps like this: Stereo EQ Equalizer Board 15 Band 2.0 Kanal Vorverstarker Ton verstellbar Preamp | eBay. On the front of the radio are buttons labeled "Bass", "Jazz", "Voice", and so on. This would correspond to some kind of EQ-Setting (for example on a smartphone). My third question is: is there some form of "programmable equalizer" to achieve this change of EQ-settings on button press?

Thanks for any help, I know my questions are pretty broad (at least the second one) but maybe there is a quick answer to that. I don't want to get into creating speakers for eternity (at least for now, maybe this will change), so I really dont want to spend money on a book.

Looking if anyone can tell me what regulators go into U5-U4. 7812-7912? I'm just not sure.

I recently got a pair of Jensen H222 (16ohm) coaxial driver and using them on open baffles. They were designed to crossover at 2000Hz. I want to build a crossover with new component for them. I already experimented disconnecting the old cap and connected a new 3.3uF Clarity Cap (which is what I have on hand) to the tweeter while keeping the woofer connecting to the original coil. It sound better already than with the old cap. Originally, they should have only a 1st order crossover but I can't be 100% certain as they are potted in a small cover.
Someone pointed out that Jensen have equivalent separate woofer and tweeter to the H222 coaxial which use the A204 (2nd order) crossover. The A204 is a 2nd order butterworth as shown in the picture. At first, I was thinking to build my crossover base on the A204. Then I read that Linkwitz has a more flat response so I am leaning more toward the Linkwitz design. I wonder what kind of difference should I hear between the 2 kind of crossover?
Also, if I want to save money on parts; can I use lower quality cap or coil for the parallel connection to the tweeter or woofer so that I can put some better one connecting in series? Or should I keep them all the same?
For the coil, would it be better to go with a smaller gauge foil or a larger gauge wire coil for the same money?

I picked up an "as is" Mesa/Boogie Subway Rocket that was salvaged from a storage unit that had some flooding.

Initial inspection shows really no water damage to speak of. The high water mark is a full foot below the amp chassis so there was no direct water intrusion. Even the speaker survived and even the cabinet is none the worse for wear. I think it got a few inches of water that quickly receded.

However, although the amp ran OK when first tested, which only happened AFTER a teardown and inspection for corrosion issues, (It's very clean, really pristine actually.) after a couple hours of operation it developed an interesting problem. The whole power supply sags badly, and the bias supply sags worst. Normal B+ to the power tubes should be about 460 volts and bias, around 12. After several seconds on, bias drops to about 6 volts and B+ is down around 380.

Note, this happens even with NO tubes in the amp. So it's not a shorted tube.

Since all the capacitors in it are of 1999 vintage by the date codes, it's time for them to go. So I ordered a full set and swapped them all out with fresh caps.

Tests repeated. Results...SAME. With fresh caps.

Basics of the Rocket 44: 4 12AX7 tubes in the preamp stage, 4 EL84/6BQ5 output tubes, 44 watts rated output. Fairly conventional topology.

Subway Rocket is nearly the same amp.

Aside from hot tubes I'm not getting any hot or burning component smells.

So, the question I'm asking and trying to troubleshoot my way to an answer is, what is dragging down the power supply, and the bias supply most of all?

I tend to believe it's not a transformer issue. If it had a bad transformer it shouldn't be coming up to rated voltage at all. Well, if I'm wrong, a new transformer for this model is not expensive.

I have had an amp with a bias power supply problem before that was a bad bias coupling cap, an Orange Drop that shorted after that amp was recapped. The increased voltage from fresh healthy caps killed the Orange Drop so that was replaced, no further problems.

This is kind of a challenge. Usually when I see a problem with high voltage supplies that are being dragged down like this, there's evidence somewhere on the board. Some component(s) are expected to get HOT and be pretty easy to find. This one...not so much.

10x 35Z5-GT vacuum tube, half-wave rectifiers. All used, untested. $20 plus shipping takes the lot.

See:

https://frank.pocnet.net/sheets/093/3/35Z5GT.pdf

12x 6W4-GT vacuum tube damping diodes. $20 plus shipping from 94591 takes all.

See:

https://frank.pocnet.net/sheets/093/6/6W4GT.pdf

9x used, untested 35L6-GT beam power tubes. $20 + shipping from 94591 takes the lot. Local pickup is possible.

Up for grabs are 8 count 'em 8 6AV5 beam power pentodes. All are used, none are tested. I have no sleeves or boxes, but I can wrap in some cardboard for safe shipping. $35 plus shipping from 94591 takes 'em.

I have a dozen 6AU5 pentode beam power tubes. I haven't tested any of them, so sold as-is. Mainly used as horizontal deflection amps, but also use in some power supplies. $35 plus shipping takes 'em. Local pickup possible. Ships from 94591.

I have roughly 39x 6AU6 pentodes, all used and untested. I can throw in about a half a dozen 6AV6's as well. These aren't specifically audio tubes, but they may be fun to play around with. Heck, you could tie 'em together with some string and hang 'em on a Christmas tree (just don't plug 'em in if you do that!)

🙂

Anyway, $30 +shipping from 94591 takes 'em.

Hi,

I really like the sound of full-range speakers and I'm going to build a pair for a friend. His living room is quite large so some bass augmentation is necessary. I've been trying to figure out how to build a FAST speaker using W8-1772 and MCM 55-2421 woofers. I plan to use 2 of these 4 ohm sub drivers in series. My dilemma is should I bi-amp the full range and sub drivers with an active crossover? If I do that the system becomes more complicated, needing two amplifiers, more cabling, etc. I also considered using separate plate amps to simplify things but the plate amps I find are either too powerful (ie PA) or don't have enough power. I'm building the speaker for a friend who isn't technically savvy and likes things really simple. So I want to let him stream from his phone via bluetooth or wifi and avoid burdening him with extra knobs and buttons to fiddle with. The last option in my mind was a passive low crossover and a 2 ch integrated amp to drive both speakers. But passive xo's are totally uncharted territory for me. Any suggestions?

Best,

Selim

I've got roughly 35 3A4 pentode power tubes, all used. I tested a couple and they tested OK. These are relatively low voltage and low power, about 600mW each class A. If anyone wants to experiment, there are plenty here to play with. I haven't got any sleeves for these, so they'll be a hassle to pack and ship. Local pickup is possible. $35 +shipping takes them all. Shipped from 94591.

I've got maybe 10 or 15 6005 / 6AQ5 beam pentode power tubes. I tested one of the 15 tubes and it measured OK, but some of them look like they might be a bit tired. You can get about 10W out of a push-pull pair. I have no sleeves, so I'll have to wrap them in paper towels or something. Bit of a hassle. $25 +shipping takes the lot. Local pickup is possible. Ships from 94591.