Hello,
I assembled a PH-16 tube phono preamp from Tubes4Hifi and have been more than happy with a modest Nagaoka MP-110.

Now I upgraded my cart to a Denon DL-103 which needs a step-up stage. Since I plan to keep the Denon for a while, I thought I could add the step-up stage directly inside the custom-built cabinet of the PH16, and save myself another box hanging around, plus connectors, cables, etc.

I plan to buy a pair of Sowter 9570 (opinions are welcome, including about the OCC option).

I never built a step up stage so I have some basic questions:

Do I need any other components other than the transformers?

Do I need any schematics, or is the wiring obvious?

How much do the Sowters heat up? Do they need special dissipation or air flow?

Any physical layout considerations, e.g. distance from power supply or signal circuitry, etc.?

Thanks,
gm

Hi everyone,

Forgive me for the rather simple question, but can anyone point out the grid stopper resistor on this schematic? I'm trying to extend my tube sockets from a PCB to fit an enclosure and the advice I was given was to solder the grid stoppers directly to the socket. I attached the schematic and the reference document I was looking at.

Any help is much appreciated. Thank you

The gain and lpf pots have no effect . You can turn them fully up or fully down and the output remains the same.

Is there a way to clean these to get them to work properly or better off just replacing them ?

If replacing them does anyone have a good part number for them ?

They are 20k pots and the lpf pot is a 20k dual gang

Hello


I own a Siemens V2275 (shall be this one vintagetools shop | Siemens 2275/1). It shall be very much similiar to Neumann V475 units.


Now I want to build a summing mixer around this unit. I can solder but otherwise I have no idea about electronic. So I hope you can help me.



What are the pros and cons of active and passive versions? I tend to build a passive unit as I am more flexible with the preamp coloration. I want something like a neve style preamp. If I go for an active summing mixer, how to include this?



Where can I find DIY Tutorials for this? Google didnt help me very well. Maybe you can 🙂



I need 8 Inputs and a stereo (preferably 2 xlr) outputs, as well as a send return switch between the summing mixer and the audio interface to be able to hear my edits live (or do I get sth wrong here)?


I just own the Siemens unit and want to include it in my productions. I also think it will be fun working on my first DIY project and learning more about the stuff I use daily.


Thanks a lot 🙂

Further to our GB for Semisouth JFETs for possible Pass J2 DIY clones, we are happy to offer also a limited amount of 2SK3497 quads and pairs.
These can be used to replace the Semisouth's for the SRPP current source.

See discussions here :
https://www.diyaudio.com/forums/pass-labs/151909-firstwatt-j2-26.html#post5892862
(Posts #1271~1274)

We have not matched all our stock.
So for now we can only offer 25 quads and 30 pairs.
That should be more than enough anyway, since most people will get Semisouth quads or twin pairs.
Quads will cost more than 2 pairs.
Pricing to follow.

Each person limited to 4 MOSFETs (1 quad or 2 pairs).
New GB, so first come first serve.


Patrick

My latest ebay purchase is six Neo3 tweeter array in curved steel frame, with passive crossover designed around 1.5khz 24dB/octave, obviously from a custom speaker project.

I did not realize they were so curved when I bought them, but I assume they should still be used standing vertically. DC resistance measures at 5.2 Ohms.
I am brainstorming ideas to integrate these Neo3 arrays with my dual 8" bass units, which currently sound awesome crossed over to Radian 475PB compression drivers at 1kHz/18dB via Bryston active crossover. The horn setup actually sounds fantastic, but this was an impulse buy. For now, I'm trying to play with alternative presentation, but I may consider just adding the Neo3 as (super)tweeters if that doesn't work out.

When I thought they were straight, I was going to just mount them on some wood panels and stand them up on top of my woofer modules, but since they are so curved, I may need to devise some sort of steel tubing contraption with help of a machine shop. Any good ideas would be greatly helpful 😀

0430202008 by drjlo2, on Flickr

0430202016 by drjlo2, on Flickr

0430202030 by drjlo2, on Flickr

I have a Mesa Boogie Triaxis preamp that appears to be in some sort of Freeze mode. The presets cannot be changed.
To be on the safe side, I provided the Eprom with new software. Unfortunately, this was not the problem either.
Through a friend I got the tip to check the CMOS ICs. With the unit he had, one of these ICs turned out to be defective, so that the whole decoder part no longer functioned. And before I have to desolder them all to test with an ic tester, I would like to debug this in circuit. I hope I also understand the operation better.
Now I can still use some help with measuring digital circuits. Because the schematic was not complete, I drew a little bit of what was missing. To clarify the question. Of course there are more ICs that are not on the schematic. But I started at the D-flip flop IC (IC43) to control the buttons on the front panel.




I see data signal on all inputs. The OE connects to gnd. And if I understand correctly on every rising edge of the CP, the input is passed to the output. But now I measure a constant high value on the CP pin. And it comes from a 3-8 decoder of the port decoder circuit. For correct operation I should expect pulses here instead of a constant high value.
Now I try to find out with my scope whether these ICs are still working properly. However, I find that difficult to find out with all those data signals on the inputs. I understand examples on YouTube. Where they put 3 switches on the input and then 8 LEDs on the output and thus switch different outputs by means of the combination of switches. However, I am also here with a number of enable inputs that are constantly provided with data.
Can you guide me through the above circuit? And how I can properly measure whether the circuit behaves well..
If anything is unclear, let me know. Then I try to explain it better.

SOLD 2 x Hypex NC400 mono kit - assembled

SOLD Does anybody know how to either delete the thread completely or at least edit the thread title to indicate item sold?


I just built 2 of the Hypex DIYclassD mono kits. They work perfectly. $1050 shipped CONUS

Used for 30 mins. They were $675 each delivered. They seem to be out of stock now.
The only liberty I took in building them is that I sanded the surfaces down a little on the inside and put thermal grease between the amp and the chassis.

Here is the detail: DIYclassd.com

I'm selling because right now I need more channels for the Linkwitz affliction.

This price is firm. I think it is a good deal. I wish somebody had made this offer when I bought them.
I am not the haggling type. If you don't want them at this price, please move on.

Thanks,

Alan

I am currently making a Class D amplifier. Four channels powered by + -92 volts. The power supply is toroidal transformer with 40,000uF per rail ( 80 000 for all PSU ) .
Since I don't want to use relays in the output, do you think it is dangerous for the speakers if these capacitors are discharged through the speakers?
The DC protection at the output will stop the power supply to the transformer ....

I am trying to build my first DIY binaural mic using Primo EM172 capsules but I can use some advice.

What I made so far look like the following mic but without XLR connections.
Creating a DIY Binaural Microphone – Matt Davison
This is a sample recording using auto levels:

AUDIO SAMPLE

Each section is approximately 10cm long in this sketch:

(Simply 2 capsules connected to a 3.5mm trs plug)

I am using a ZOOM F1 portable audio recorder but I am experiencing more noise than expected...

I soldered the capsules using a 15W soldering iron and did not exceed 2-3s per capsule.

My questions:

How can I be sure the capsules aren't damaged by soldering or at least compare and measure them noise-wise against other mics?

My ZOOM F1 provides 2.5V PIP. I've read 5-10V would improve noise levels. What are your suggestions improving my setup and getting the most out of these capsules?

Thanks in advance!

Hi!

I have a MTX 5601 amp, its working but doing weird noise when i hook up the subwofers. It has +- 60 v, +- 15 v, everything looks great. But subwofers move very weird, they move towards like dc voltage on subwofers then hit the bass. More weird is the fan, it turns on every time the subwofer hits.

I am trying to build a simple regulator to power the voltage and driver stages of a tube amplifier that I am building, but it doesn't seem to be working. I want 300 volts out. The front end of the amplifier draws about 50 ma. On the attached schematic, the voltages that I am getting (with all tubes in place)are shown in boxes with arrows pointing to the DMV attachment points. I have tried R values (the resistor between B+ and the zener string) from 18.2k ohm down to 500 ohm. I have swapped in a new IRF 840. I have swapped in new zeners. I have checked for shorts to the heatsink. I am still getting about 320 volts at the top of the zener string with all values of R. I am getting about 330 volts +/- 3 volts at the output. I have built this style of regulator before, with good results. (meaning that I get the voltage out that I expected) What am I doing wrong? What should I try next?

Hi,
I recently acquired a pair of SL3 in poor condition.
They've been slightly water damage and will require woodwork and reshaping.
one speaker is working fine, the other one has very limited sound coming from the panel. the sound produced is identical regardless the power is on or off.

I swapped the panels, both panels work fine, the issue is related to the electronic in the faulty SL3 speaker.
I opened it , it has a MLPS103 rev h board.
Both exterior and interior leds are on.
Thanks to the shared knowledge on the forum, I could find the board diagram and started investigations.
the D26 diode was visibly in bad shape , I replaced it with a spare one.
I also measured the bias supply voltage at 260v, between D26 and D27.

I'll continue researching but my electronic skills are very limited, any help on how to diagnose the issue is very welcome !!!!

Many thanks in advance and kudos for the friendship and knowledge shared on this amazing forum.

Hi All,
How about a mono block good for 20W to 1KW+ based on SiLabs ISO drivers with a few nifty features and a considerable mod/DIY appeal?

Context

I’ve been lurking a lot around here lately, studying various class-d designs being proposed, discussed and implemented. Back in may this year, somebody asked about a silicon labs driver ic and whether it would be a good alternative to the various IRS designs. Here is the relevant web page. Having been familiar with Silicon Labs microcontrollers for a longtime (my job is analog/digital/RF/firmware design, DISCLAIMER: I am in no way involved with Silabs), I became aware of their class D drivers last year when they were first presented. Neat chip I thought, simple, well designed and with a few good features: isolated; precisely settable dead time down to a couple nanoseconds; comes in two driving strengths (0.5A for up to 400W and 4A for higher output designs); supports supply rails up to +/-750V (if that tickles your fancy). I liked the fact that they left out the error amp and modulator.
Other specs sounded good, and at that point I wondered how an amp based on the chip would sound in the real world. I also wondered why it hadn’t caught any traction in the DIY community. Maybe the manufacturer just isn’t known enough outside the microcontroller or RF space. Also, DIY’ers aren’t particularly attracted to SMD packages, and the Silicon Labs drivers do not come in DIP.

Silicon Labs do offer a reference design (RD), the Si824xClassD-KIT, delivering 2x 120W into 8 Ohms, for 299 USD (Mouser). After reading its user’s guide, I decided the board wasn’t for me. Not for use as one of my amps anyway. Reasons: a) form factor b) the protection circuitry and logic is a bit cluttered IMO c) last but not least, its price.

The plan

So, long story short, I started designing my own. Actually I’m still in the process, but would like to get early feedback and comments before committing to it, then fabbing and stuffing a few PCBs for myself and anyone else here interested in trying out the design, possibly with different configurations.

The highlights

- Mono block, BTL, uses two Si824x chips
- single supply from 12 to maybe 100V
- supports a separate 12V supply for gate drivers and input/logic
- undervoltage lockout, (over)current sensing for each arm
- heatsink temperature sensing, plus true wattmeter on output
- protection circuitry calibration, logic and UI on daughterboard
- daughterboard possibly uses microcontroller for shutdown logic and more
- mostly SMD, some TH components for easier adapting/experimenting

Form Factor

For starters, here is the form factor I came up with so far. (No routing yet, I’d like to stay some more time in the placement phase). Measuring 90 by 60mm, it fits onto a heatsink plate or extruded profile. Output MOSFETs are TO-220, mounted underneath the board which has holes drilled to access the mounting screws for the transistors.
http://www.diyaudio.com/forums/attachment.php?attachmentid=237851&stc=1&d=1314661880

Two TO-220 BJTs are mounted in the same way. One is the regulator for the gate drive voltage, and the other is a Vbe temperature sensor.
Input is at the top of the board via an RCA jack, while output and power connections are at the bottom. These can be either screw terminal blocks, or faston males.
Below are two possible heatsink mounting options, the first could be built into a (low power) active speaker, the second is beefier.

http://www.diyaudio.com/forums/attachment.php?attachmentid=237854&stc=1&d=1314661880

Of course, many more variations are feasible. BTW can you tell I have been fighting with Sketchup?

http://www.diyaudio.com/forums/attachment.php?attachmentid=237855&stc=1&d=1314661880

The two metal cubes are the output inductors. The layout accomodates the SAGAMI as in the RD, the Wurth WE-PD, plus there is enough real estate to accomodate larger toroids.

Architecture

The idea is to keep the signal path very much in line with the Silabs reference design, while re-inventing the protection circuitry and logic wheels, and adding a few niceties here and there. I'll post and go through the schematics right after this. I went for SMD mostly because I am familiar with it, but am leaving several key components as through hole. Apart from the power MOSFETs, “key” means that the component value will likely have to change with different power supply / output levels, or, as in the case of the dead time setting resistors, will depend on the chosen MOSFETs and will have to be experimented with.
The result is a ucd (self-clocking), mono block in BTL configuration able to pump 1KW and more depending on its single supply rail (and the choice of MOSFETs, and...). For myself here at home, I’d be happy with two channels with 50W into 4Ohms, using a lowly 24V/3A SMPS, or two 12V batteries. Later perhaps a third, with higher power, to drive a subwoofer.

Ok, I’ll post the schematics in a bit, or rather tomorrow, it’s getting late. Thanks for reading.

Hi Anything out there
Cheers all

I was able to take over a Triaxis with the following problem:
The display does not respond to the buttons. So all parameters remain unchanged when one of the buttons is pressed.
As far as I have tested, the Triaxis also does not respond to my midi signals from my foot controller. But I don't know if this is related to each other.
But what I want to start with is to get the buttons on the front panel working again.

I finally succeeded in having the presets changed by removing the battery and completely discharging the capacitor. It has now shifted from "program" 25 to "program" 1. With the corresponding settings.
However, the problem persists that it is not possible to change the settings. However, I found out by switching the unit off and on once, that at some moments the unit does not start up completely. Most LED displays will then remain empty, the 'Dynamic Voice' will occasionally indicate 5.0 and at another moment only the dot between the digits of other displays. Furthermore, all the LEDs of the 'RHY', 'LD1' and 'LD2' LEDs are lit.
This seems to indicate that something is not going well during startup.
This happens incidentally very sporadically.
Still have the idea that something goes wrong in the "system reset" part. But I am not sure yet. But it seems that the program does not start completely and therefore seems to freeze. Attached is the video showing how the start-up goes wrong.
YouTube

Below pictures of the part that is probably about.






I have already replaced the 2 large blue capacitors along the LM323 as they looked suspicious, but this did not produce any positive results. The problem persists.




Below the digital part of the control. I expect the problem to be here. But I don't know where ?!




Anyone have experience with this? Or who can help me with troubleshooting?

Dear Friends,

Inspired by the discussions around the possible schematics to use my father came up with the idea to combine the driver stage from the VTA ST70 AMP using 6SN7 tubes with the output of Mark III based on KT88 for more power. The draft of the schematics is attached.

Power transformed will be of toroid type giving 250 Wt output. B+ voltage before the choke will be 504 V.
I have some questions regarding the schematics:
1. Is this in general fine or have I missed something?
2. I want a OT with wide frequency response. The original schematics shows a 4.3K transformer. I found the LL1679-PP 9k7, 4k5, 2k6, giving 45, 105, 188 Watt transformer. Will it suite the needs? Or can you recommend something else?
3. There will be 2 chokes (1 per channel power supply). The Mk3 has this choke: 1.75 Henries, 200ma. DC current, 62 ohms, 400 vdc (max) 10% Tolerance. are these parameters enough? I saw in other schematics that chokes of 4-8 Henries are used.
4. Various schematics advice different capacity of C13 and C15 - from 22 to 47 uF. The more the better?
5. Did I correctly draw up the NFB? It is taken from the VTA 70 schematics.
6. Any suggestions on the capacitor types? I can take made in China or some European brands?
7. Is there any software to imitate and check how would this project actually work and whether some changes are needed?

Thank you in beforehand for your help

Rotel RDD 980 transport with Philips CDM9 (little sister of the CDM9pro) Arguably the CDM9 is the end of the line for the higher quality Philips transports. You will need your own DAC!

Just reduced to $199 plus actual cost of shipping and I will eat PP.

All functions work as designed including optical. Had to press ear ONTO the chassis to actually hear it was running. All functions work via remote as well, except tray does not open which is by design . Tray will close when play is pressed.



This Rotel is a back up that never needed to be used as a backup and has been in storage in my closet. I of course have used it a few times and I ordered the replacement remote (Rotel RR924)for it probably 10yrs ago

Audiogon bluebook says new retail was $700. Rotel's entry level higher quality in response to plethora of transports being built back then.

replaced door belt quite awhile ago. Readily available still.

Will be well packed as is my obsession --see my fb on Audiogon w/same user name as here. buyer pays for actual cost of shipping and I will eat PP. FYI--if you can take delivery at a business it will cost less for shipping via Fedex ground rather than home delivery rate. I use my account to calculate cost. If pics do not upload see my listing on US Audio Mart.

So sad. I'm sure over the years several of us have bought parts/components from Mendelsons.
This could be a great opportunity to pick up components/parts for cheap.

Upcoming Auctions - Cincinnati Industrial Auctioneers - Mendelsons Liquidation Outlet Auction 1

No affiliation.

Rgds
Mayank

Ultralow-noise (4 µVRMS) low-dropout linear regulators (LDO) 5/3PINs with Enable and Feedback input PINs, 15x25mm. Replacement for LM78xx TO-220 package (in 3PIN Mode)

Presenting new PCB with TPS7A4700 Ultra Low Noise Low Drop Out Voltage Regulator. The idea to build PCB adapter for TPS7A4700 QFN Package with 78xx Pin Compatible Layout is not new, but only few of them allow you to utilize all advanced features of TPS7A4700.


Features
• Input Voltage Range : +3 VDC to +25 VDC
• Output Voltage Noise : 4 μVRMS (10 Hz, 100 kHz)
• Power-Supply Ripple Rejection:
– 82 dB (100 Hz)
– ≥ 55 dB (10 Hz, 10 MHz)
• ANY-OUT™ Voltage Modes:
– User-Programmable Output via Solder pads (fig. 2a)
– Output Voltage Range: +1.4 V to +20.5 V (in 0.1V step)
• Output Current: 1 A
• Dropout Voltage: 307 mV at 1 A
• CMOS Logic Level-Compatible Enable Pin, if enable is not required, tie EN to IN. (“EN” Solder Pad, fig. 2b)
• Sense/FB Pin - This pin must be connected to OUT, can be connected to the point of load to maximize accuracy, tie FB/Sense to OUT if external connection not used by “FB” Solder Pad (fig. 2c)
• Built-In Fixed Current Limit and Thermal Shutdown
• PCB size: 25.4x15mm (approx. 1.0”x0.6”)
– Vertical or Horizontal mount, compatible with most of the TO-220 package footprints
• Operating Temperature Range:–40°C to 125°C
PCB Mounting Options
Can be mounted vertically (use angled headers) or horizontally (use straight headers), compatible with most of the TO-220 horizontal footprints due to oval shaped mounting hole.

Heatsinks
It is important to use sufficient heatsinks, the dispatched power can be calculated P=(Vin-Vout)*I. Back side of the PCB does not have any traces – only output pads and DC grounded copper pour. Heatsink can be attached directly to PCB if input/output pads not covered by it. Oval shape of the mounting hole also allows most of the standard heatsinks to be used safely without any modification.


Schematic Diagram

BOM (Bill of Materials)
TPS7A4700 x1: IC, Low Noise Power Solution, Texas instruments – United States
GRM31CR71E106KA12L x5: Cap Ceramic 10uF 25V X7R 10% SMD1206, Murata – Japan
GRM31MR71E105KA01L x1: Cap Ceramic 1uF 25V X7R 10% SMD1206, Murata – Japan

It is available on Ebay for $23.95 (with free shipping)

For sale TOROID 230VAC - 8X/39VAC out +2X/21VAC out

this is from a broken Samson amp.

70EUR + shiping

Dear all,

I would like to introduce to you a new type of inductor - the Flat Foil inductor.
Maybe its concept is not so new, but currently it's not available on the market. Though some small flat inductors made of thick copper wires are available (i.e. edgewise inductors), but none of them are made of thin copper foils as this one.

Please refer to the picture of its first hand-made sample, unlike the currently available spiral foil inductors, though the new coil is also made of foils, but the copper foils are in flat (horizontal) directions and folded up to make the coil loops.

Spec of the sample:
inner diameter = 42mm
outer diameter = 66mm
copper foil thickness = 100um width = 12mm
layers N = 93
inductance = 453uH @ 100Hz (ACR=0.3ohm)
inductance = 375uH @ 1kHz (ACR=1.462ohm)
DCR = 0.3ohm

I will briefly describe its advantages as following:
1. Full symmetric structure
- unlike the spiral foil coils which is not symmetric in structure (inner side and outer side), Flat Foil inductors are fully symmetric.
2. No polarity issue
- unlike the spiral foil coils which inherently have polarity issue, full symmetric structure guarantees no polarity.
3. Least vibration
- Flat foils have the least vibration because the flat foil direction is parallel to the Lorentz force, while the spiral foil coils are perpendicular to the Lorentz force and could vibrate easily.
4. Better heat dissipation
- Flat foils conduct the core heat from its center to the outer side, each layer is a heat sink for the core, core heat is evenly dissipated.
5. Least heat expansion deformation
- unlike the spiral foil coils, heat expansion will not cause deformation of the coil.
6. Each layer has the same inductance
- while each layer of the spiral foil coils has different diameter and therefore different inductance for each layer.
7. Less leakage between layers
- while the spiral foil coils have greater leakage flux between layer gaps.
8. Least Eddy current, least mutual inductance
- while the spiral foil coils will induce larger Eddy current when an external vertical magnetic flux penetrates its foil surface. Flat Foil coils have the least mutual inductance because its foil surface is parallel to the external vertical magnetic flux, and therefore the least eddy current.

I am comparing the Flat foil coils with spiral foil coils only, but I think it's pretty much the same when comparing to the wire wound coils.

What do you think about this type of inductors, would it be better when used in the crossover?

Your comments are welcome and will be highly appreciated!

Thanks in advance.

Hi !
I recently found a pair of ML SL3 in poor condition and started my quest to reshape and repair them.
I was amazed by the friendship and knowledge shared on DiyAudio, hope I can learn and contribute to it.

Hi, I live in New South Wales, Wauchope. I do have a sound system with a Yamaha receiver and Canton speakers. Getting a little deafer and got myself earphones so wife can have the tv as low as she wants and I listen to the earphones via bluetooth, which I can turn up as loud as I want it. Thought of upgrading my speakers and receiver and splash some money. Then I came across you and got the idea to build my own speakers. It looks very involved, BUT there are good tutorials and I ordered some books from the US of A.

I thought that I had seen plans for boxes and crossovers and what drivers to use. Cant find it again. Could you please show me where on the forum I could find them.

Also links to were I could get these online.

Thank you and my regards to all.
Werner

So the front panel is 8mm thick and I need to make a 19mm hole.
What's the best way to do that - using a "standard" 19mm HSS drill bit?
Or are there other / better ways?

Hi.
I have this Italia amp, and i love the sound of it. But i want to adjust bias.
Does anyone know the voltage? And witch resistors i should measure from?

Thanx in advance.

Hello.

Bought these attenuators from e-bay. I wonder where the signal in/out and ground should be connected?

2P 24 Step Attenuator Volume Control Pot Log A 100K Mono Potentiometer Ladder | eBay

All,

As asked by few members of the audio community, I’m pleased to share with you (in English) my Project, launched two years ago.
Originally, this project has been launched in order to replace my existing Elipson horus 5 Loudspeakers. I’m working to improve these horus 5 now 😎 .
A bit more than 2 years ago, my knowledge in Loudspeakers creation was really limited (almost null). So I started to post something on a french Forum (as I’m french).
Everything started here : http://www.homecinema-fr.com/forum/posting.php?mode=edit&f=1055&p=170079129
As usual this project aims at the DIY community.

None of schematics, illustrations or information presented here may be used for commercial purposes without my written consent.

Special thank to : Jerome69 (Rodolphe) for his wide support during the project life.

- - - - - Project description - - - - -

Name of these new speakers : ASTASIA (http://en.wikipedia.org/wiki/Euglena)

Technical Specifications :
- Speaker : 3 drivers – Bass Reflex
- Sensibility : 86.5 dB at 1m / 2.83V RMS
- Bandwidth : 29Hz - 40Khz (+3/-3 dB)
- Bandwidth : 50 Hz - 20Khz (+1/-1 dB) (50Hz is an estimate … cannot measure at this Frequency)
- Spécificity : Vent under the Box

Type of Speakers :
- Boomer: Seas - CA22RNX http://www.seas.no/images/stories/prestige/pdfdatasheet/h1288_ca22rnx_datasheet.pdf
- Medium: Seas - MCA15RCY http://www.seas.no/images/stories/prestige/pdfdatasheet/h1262_mca15rcy_datasheet_.pdf
- Tweeter: VIFA Vifa XT25TG30-04 http://www.tymphany.com/files/products/pdf/XT25TG30-04.pdf

Xover Specification:
- The Boomer is filtered using a Linkwitz Riley (Order 2) / 12dB/oct with a Fc set at 500Hz (low pass filter)
- The Medium is filtered using a Linkwitz Riley (Order 2) / 12dB/oct with a Fc set at 500Hz (high pass filter)
- The Medium is filtered using a Linkwitz Riley (Order 4) / 24dB/oct with a Fc set at 3000Hz (Low pass filter)
- The tweeter is filtered using a Linkwitz Riley (Order 4) / 24dB/oct with a Fc set at 3000Hz (high pass filter)

Xover is fairly simple compares to the high level of the filter :
- 5 Capacitors (All Capacitors are MKP – SCR or Audyn Cap QS )
- 4 Self (Air self from Mundorf 1.4mm² / Ferrite Self HQ58 type from IT for the boomer)
- 5 resistors (MOX 10W)

- > nothing ESOTERIC here !!!! -

end of part 1 -

Hello everyone!

I'm a recently retired electrical engineer with time on my hands. I always liked electronics growing up and fiddled with making stuff on and off until college and career consumed much of time. Recently I have been going over my 1979 era stereo equipment* and picked up a desire to make a set of speakers. The AR-18's are great little speakers but want something with a bit better performance and more visually appealing.

* My original stuff. All purchased at Service Merchandise (I miss that store) with the exception of the AR-18's.
Technics SU-7300 Int. Amp
Pioneer TX-6800 Tuner
Pioneer PL-518 Turntable
Acoutic Research AR-18 Speakers

Hi everybody,

at first I´d like to introduce myself.

I´am a guy, living in Berlin, Germany who got infected with the DIY-Tube amp-Virus a few years ago.

My first projects were always quite low powered mono and stereo amps.
As power switches I always used vintage toggle switches, since they are rather hard to destroy, look gorgeous and I had them lying around anyways.
Currently I am building a 50Watts Stereo Amp including an RIAA Pre-Amp.
The design is going to get a rather modern looking casing.
Therefore, I ordered different switches which unfortunately look or at least sound rather cheap.

So does anybody know where to purchase good, sturdy power switches which look and feel good?

Thanks a lot in advance!

Greetings from Berlin,
Mobi90

Wonder anyone can trouble shoot my Tivoli cube in the Toronto area.Its started to flash green/red/blue indicating it need service.No sound.Controls in the back not working.

Hi,

I am not sure whether this query has been asked before I will try to explain ask here quickly. Those who have expertise, eg Curryman or those who have experience with is query I welcomed your inputs. I am using the Minidsp as digital Speakers x-over like more users.
After reading Curryman application notes on his 9023 DAC I am thinking of upgrading my current Minidsp to speakers setup. Refer to my attachment for my query.

Current Set-up
It has one weakness, the DAC converts digital signal to analog and the Minidsp converts the analog signal internally and then converts back to analog again. By changing the quality of the DAC in the set-up also changes the output audio quality. That's to be expected.

New Set-up
It has an advantage of purely digital outputs all the way till the audio signal is converted back to analog via the DAC 1 & 2.
Questions:

a. Will this configuration work? I don't have to use Mclk, why?
b. If it works has anyone use this configuration, if so do you experienced improvement in sound quality?

Any suggestions for improvements of the new set-up are welcomed e.g. using other convertors like Minisharc or Nanodigi.
Thanks.

Hello, I am from Sri Lanka,

I seek help to find out why my Oppo-BDP83 does not display picture and the audio. I did change the HDMI cables, connected a different monitor, yet the problem exists. Can anyone help me how to get about on the servicing it?

Cheers

Mohan

I have two of these monster subs. Great in a 40 litre sealed enclosure - clean low deep bass. These were about £300 each I think when i got them.

Wanting £150 for the pair.

Collection (UK) is preferred as they are really heavy but postage at an additional cost can be arranged.

I'm wonering what are the cons of doing a circulr array of small 2.5-3 inch midrange drivers around a tweeter ? . Just like in tekton speakers but with surrounding midranges instead of tweeters.

https://positive-feedback.com/wp-content/uploads/2018/07/impact-a-10_orig.jpg

I couldnt edit the title for some reason? Its supposed to say ''BlueTooth on Vintage Amps.'' Anyway, I bought a couple of No Name, cheap 4.2 version Bluetooth Transmitter/Receiver modules to see how they would go? Well, they turned out to be way above expectations, in fact, they are excellent, the only thing I could pick on them about was if I left the Transmitter from my PC charging on the PC USB it would pick up the hard drive noise when listening to music. The internal batteries are supposed to last 8 hours but according to someone they only last 4 hours? Well, 4 hours is plenty enough time for me. I plug the Receiver on the amplifier into the amps aux and run its battery charger to the power strip. The Transmitter is plugged into the headphone jack on the PC. When I first tried these I tested them out on YouTubes Audiophile Test videos and I was blown away at the quality. HIFI Wireless Audio Bluetooth Receiver Transmitter 3.5MM RCA USB Music Adapter | eBay

I have a problem with my Philips FA960 integrated. The bulbs around the volume control and power switch are out. I replaced them about a year ago, and they were fine for a while, but now I find that the bulbs themselves are fine, but there's no current getting to them. I've checked the wiring, but don't see anything obvious.


Anyone experience anything similar with a Philips or similar Marantz amp of this era ((1980s)?

Hi All.

As part of the crossover rebuild of my Mordaunt Short MS 45Ti Loudspeakers I'm looking to replace the 2 Thermistors, which might be Varistors.

As it's been indicated earlier 40 year old Thermistors can become problematic.

Each crossover contains two Thermistors, each of different value.

Thermistor 1 is marked "MEXICO -35 805D"

Thermistor 2 is marked "MEXICO -070 802C"

I haven't been able to track down s supplier or find any technical specs.
The replacements needn't be identical as long as they function with the same values.

Element 14 might have something suitable but their website seems to be set up for those who know what they're ordering.

https://au.element14.com/

I couldn't find anything online regarding these.

thanks

Cliff

Amp will not power up .

Here is what I get on the SG3526

Pin 1:4.98
Pin 2:0.00
Pin 3:4.20
Pin 4:4.74
Pin 5:4.98
Pin 6:0.00
Pin 7:0.00
Pin 8:0.00
Pin 9:3.62
Pin 10:0.00
Pin 11:0.00
Pin 12:1.29
Pin 13:0.03
Pin 14:13.30
Pin 15:0.00
Pin 16:0.00
Pin 17:13.31
Pin 18:5.01

I am looking to replace some 6800uf, 63v filter caps on a Philips FA960 amp.


I wanted to go a little larger, but there are few offerings. It looks like I will have to stick with 6800uf.



Any advice on brands or lines?

Hey all

I’m modifying a Marantz CD63. It has 2 clock boards in it (Flea boards) both fed from a single additional power supply, connected to the DAC and servo chip.

The clocks have ground connections at the crystal end and the power input end. When I just had the one clock, one end’s ground was connected at the new power supply and the other end connected to the board just next to the DAC.

Now I’ve added a second clock I’m a bit confused as to how I should connect the grounds. If I connect this new one in the same way as the DAC clock then I think I’ve created a ground loop?

If I was to connect two clock boards, one feeding the servo and the other the DAC and decoder, both fed from the same external power supply, can anyone help as to where all the grounds should be going?? Obviously one from the clock board from the DAC but the rest I can’t get my head around.

TIA 😀

So, I'm thinking of adding a new music centre to my current Audio (and vídeo) system.
Starting from the existing gear:
Sources:

• Garrard SB125 Turntable + Cambridge Audio Phono Pre Amp
• Sony CDP 590
• PlayStation 4 (Blue Ray/DVD)

Amp: Prima Luna ProLogue 2
Speakers: Visonik Revo 4
TV: Philips Cineos 9631D/10
Others: Several laptops, a NAS for data backup and both Android and iOS smartphones. DIY interconnect and speaker cables (low capacitance).


Right now the PS4 is connected with the TV by hdmi and the TV analog áudio out is connected to one of the Amp channels (one still free) and that's the only way I can play YouTube, Plex and other streaming platforms on my system.


What do I want a music centre for? Well, I have a large CD collection that I will keep listening, and some vinyl records that I sometimes also listen. But sometimes I miss a song that I would like to stream in Hi-Res Quality to my system. I also want to start building a Hi-Res music library.


What are my requirements:

• Good value for Money
• Hi-Res playing capabilities
• Easy to operate
• Able to search the web to find the music I want and play it at once (from a smartphone or laptop)
• Able to stream from Hi-Res platforms (don't know which yet)

What are my ideas right now:

• Raspberry Pi 4 (4GB?) with the oficial PSU
• HDD (I have an old 500GB Iomega box and a newer WD My Passport Ultra)
• SMSL Sanskript 10th aniversary Mk.II (109€) DAC (great specs and measurements, better than higer priced equipments and all HAT boards available)

This would revamp my system, enable me to connect the PS4 audio(Toslink) and the TV (Coaxial Digital) directly to the DAC and, above all to have a remote controled Hi-Res server and streamer connected to my Prima Luna.


What are my main doubts:

• I don't have a clue of what OS distribution should I install on the RPi
• I'd like to start this with a very precise parts and software list
• I'm more confortable with soldering and woodworking than coding

All suggestions will be welcomed!


Thank you!

I have a pair of these very old drivers that need reconing but sadly recone kits arn't available. So what to do with them toss them in the trash or offer them on the Swap Meet for $ 1 plus postage. Here is a stock photo of these old drivers mine arn't in this good a shape, one is even missing the cone.

Since listening to the NE5534 performing I/V duties in a CD player and also as balanced to unbalanced converter in a DAC I have found it difficult to reconcile the many denigrating statements written by audio DIYers with the sound coming forth from this remarkable op-amp. Having reflected on this conflict of opinions I am offering my own explanation as to why the NE5534 receives such a bad press from many, though not all.


The background...
I had until recently been using a discrete op-amp which, with a FET input, sounded slightly better than an OPA627 biased into class with a ccs, and with a BJT input (my preferred option), improved on the AD797 (again with a ccs). Having read so much negative comment on the NE5534/2 I had not contemplated trying this op-amp, instead evaluating many other more modern types, including those already mentioned along side others, the LM6171, AD825, OPA134 etc. It was therefore a surprise to find the NE5534 the most musically engaging of the lot.


Tarred with the same brush...
The (uncompensated) NE5534 sounds more refined than the NE5532 and should be judged on its own merit. My understanding is that the NE5534 is the single version of the NE5533, not the NE5532!


Mass psychology...
No comment!


The sound...
(Uncompensated, with a 2mA ccs on the output)
In my view, after extensive listening comparisons with other op-amps, the NE5534 possibly works against itself. Its superb purity and focus impart a subjective quality that can be wrongly interpreted as detached and distant, lacking ‘body’ and ‘drive’, however it is perhaps these qualities that set the NE5534 apart from the rest. Consider a live concert where you might be sitting half way back in the auditorium. Individual instruments do sound distant, they do sound small and there is a distinct space between them and the walls of the auditorium. It does not sound larger than life. Due to various factors including microphone positioning a recording will usually allow reproduction of this perspective only to a degree, though interestingly there seems to be a current trend towards a more distant (and therefore more realistic) sound in more modern recordings. But this is precisely the strength of the NE5534 in my view, it does not sound larger than life! For those of us who like to be transported to a seat in the auditorium the NE5534 is the just the ‘ticket’, it convincingly recreates the acoustic where the recording took place, natural detail is portrayed coherently and the smooth, wide-open treble is the icing on the cake. For those who like their music larger than life and who prefer the orchestra in their room, it probably isn’t.

Tim.

WTB: Eminence Definimax 4015LF, 1 peace, I already have 1. Due to high shipping costs only Germany / Europe.
I have an OB like the Pass, I bougth 2 woofers, but 1 was an 4015ULF with quite different parameters. May be I dont hear it, but they have a measurable different output.

I would also swap the last for an 4015LF, please make your offer.


best regards

Helmut

Hi!
I sometimes have fantasies...
This time, it would be an amp with the power-Switch on top of it.
I imagine something like a push-Button, D≈20mm, height >= 30 mm, that would switch with a fat „ka-chunk“...
Been searching on various places but haven’t found it.
Where could be a place to find crazy stuff like this?

Thanks!
David

Hi folks, wonder if you can help with a couple of service-related questions on a Trace Elliot Super Tramp guitar amp I'm going to work on for a friend.

1. Is there any service manual for these other than the schematics I already have? Would be nice to have voltages, biasing, tests, that sort of thing.

2. I saw mention of the Super Tramp having an EC83/12AX7 preamp tube. There's no tube in any schematic I've seen. What's with that?

I don't have the amp in hand yet, just a description that it sounds squawky or something. So I'll need to do the usual tests. Anyway, if anyone can help clarify those two points, much appreciated!

--KW

Gentlemen

I purchased but haven't received as yet a PA-3 preamp. According to what I have been told it has 3 5814A tubes. It is non-working and I would like to find some information before I tear into it to either gut it and start over or to repair it.

Frank

It looks like I may have to draw up yet another schematic. OH GOD!

Any help or information would be much appreciated.


Joe

Pictured are some of my collection of tone-arm plugs. The first 3 fit my SME V series tonearms perfectly. The OEM tonearm cable is the right angle plug. The last 2 are expensive custom replacements which are useless because of the sloppy fit. Any ideas as to why the variance in dimensions? The Jelco is made in Japan if it helps. The 2 silver ones are from E.U. but one fits and the other doesn't. Go figure.

Hi folks,

I'm having issues with the High cut filter push button switch on my Mitsubishi DA-R20. I've tried cleaning it multiple times but it still wants to be a problem child. I could easily just bypass it but would like to replace it if possible but I can't locate one. Any suggestions on a suitable replacement option? The svcs manual shows it as part M07461455 if that helps at all.

Thanks!

Hello, would an older Phillip's console tube amp be worth developing into a tube amplifier without console?

To no surprise do cheap, low quality gear come with the lowest quality power supply and shortest possible cables! So I am now the "happy" owner of a mid cable power supply that have to be on my table, way to near my scope and other gear.
Is it possible to buy / make a enclosure that reduce the EMI or maybe almost eliminate them?

First of all I'd like to say that I have no experience restoring audio, but I am pretty handy and up for a challenge. With a good explanation I'll be ready to go. I posted this question in another thread but there was no response, so I thought a new thread might get more attention. Also this is basically my first post and I might not know all the lingo. Anyway, here we go.



I have a Sony MHC-7900 system with Sony SA-H7900 speakers. The system has been collecting dust for the past twenty-something years. I'd like to revive them since it is supposed to be a great system, but the tweeters (Sony 1-504-388-11) in the SA-H7900s are very quiet. I already checked if it was an equalizer problem and it was not. With a flat equalizer there is hardly any sound coming from the tweeters. This problem is also shortly discussed in this thread, but that hasn't been of much help.


One tweeter was slightly quieter than the other. I took it apart and cleaned it following this youtube video. I first cleaned it with dish soap, which made a small improvement. Then I did it again with cleaning spirit, which made no noticable difference.


As far as I understand either the electrostatic foil is not conductive anymore or the high voltage circuit doesn't work. The fact that both speakers have the same problem makes me think that the foil is the culprit, not the circuit. For those that are interested, I found a service manual of this loudspeaker.

Does anyone know what to do next? Are there still replacement parts available? I'd love to restore this system in it's old glory. Thanks in advance!

The Pi is small enough to fit inside the DEQ and bypass USB/spdif conversion if direct signal connection is possible. There should be a jump in SQ.

Will the DEQ allow this if I'm prepared to forego all other external spdif connections and if so, how to go about it and any clock issue? Adding a separate Pi power supply is assumed. Thanks!

Hi,

While troubleshooting my Linn 2250 amplifier I found than one of the channels has a DC offset of 1 volt. Each channel has 3 TDA7293 chipamps in parallel configuration.

My question is, is there a way to determine in situ which TDA7293 is faulty without replacing all 3 chipamps?

Hi everyone I am planning on experimenting with transmission line subwoofer and was wondering if t line subwoofer is really worth the extra box size.
As far as I know t line has flatter response and slower rolloff so it would get deeper than ported.
We are talking about a box for cheap generic 12 inch subwoofer. I have some parameters for these drivers and i can provide them if needed.
I am on a budget currently and i already have these drivers and want to experiment with them until I can upgrade.

Has anyone ever replaced their own NiCad battery in their Tandberg 3001 or 3011 tuner and found a good replacment?

Dear all

have a pair of original Mission 753 which were working perfectly.

But I tried to do the usual tweeter-grill removal mod.

Seemed to go okay, but I noticed the fine copper wire around the tweeter came a bit loose. It doesn't seem broken though.

When I reassembled everything the tweeter doesn't work at all 🙁

I've tried reassembling several times, but no luck.

Does the copper wire need to be fully wound around the tweeter edge or is some of the wire meant to go into the groove in the 'base' (where the foam plug has a groove around it)?

I hope someone can help please...

Aikido Cathode Follower [ACF] Buffer

For 6DJ8, non White-Cathode-Follower configuration, do I:
1. jumper R5? (Y/N)
2. jumper R11? (Y/N)
3. Omit C5 along with C3?

It would be great to have these definitively answered, since that's the last hold up to complting this project!

Thanks in advance!

Just joined and new to forums.
Looking for info to build a reverb remote pedal for this amp. The socket is a TRS stereo jack and I don't quite understand why from the schematic. Does anyone have any info on this please.

My parents found the time to completely clear out their house during the current crisis and threatened to throw all of my old amplifiers, from back in the day, away.

I could not allow this and have taken possession of every bit of crap... I mean audio equipment I had bought as a kid and young adult.

Some of has gone straight in the bin, (Longmill EQ anyone? 😀) and some is worth saving.

I don’t know how I blew this one up, but it was gone good and proper.

The primary side caps were literally blown and the thing doesn’t even power up enough to draw any current from my current limited PSU.

There is a little spark from the caps charging but nothing else when the remote is connected.

There is 12v on the PSU FETs but no oscillation, I suspect a dead 494 but it’s a surface mount component and I don't have a hot air soldering station or any chipquik...

Could there be something simple that I may have missed to check first?

I have wanted to build the EL84 version for a while and scrounged up all the parts needed to do it while we are in lockdown here. The chassis is made out of bits and pieces of chassis and scrap. The HV transformer is a 300w 120/240v adapter toroid so it’s much bigger than needed. I used 2 low voltage transformers, 1 for the +20v driver power and +12.6v for the 12ax7 and a second winding for the -36v bias voltage. A centre tapped transformer supplies 2 x 6.3vac for the power tubes.
I have regulated 12.6v 12ax7 filament,-36 for the bias and +295 for the B+. I used the Power supply board and modified it extensively to produce the regulated voltages I needed. I also re configured the relay to use the normally closed contacts to hold the HV to 100v for The delay time which I set to 1 minute. For output transformers I used the Toroidy 8k UL transformer which I have had since ordering them along with the EL34 outputs for that BH version. These are also quite large, being rated at 40w.
Fitting all this in the chassis became a big job. I was also concerned about hum issues with AC on the power tube filaments and 3 transformers in the mix.
Oh! And I painted it yellow and brown. Looking through my paint supply I found black but wanted something brighter, to lift the mood during these stressful times.
I ended up attaching the RCA connectors to the front sides of the chassis rather than the top, where I have seen it done before. I always thought it would be awkward and in the way to have the cables coming into the top of the chassis so I tried something different.
Bias adjustment was another issue. I did not have room to mount a switch and meter like on the EL34. So I came up with using the 8 pin RJ45 internet connector to bring up to 8 wires to the side of the top cover. I then connect a network cable with the other end connected to a terminal strip and can easily measure the low voltage bias voltages. I still have 2 wires of 8 which could be used to monitor a divided down HV and -bias voltage. I will post again about the tubes and operating points etc used.

Hello,
I have 2 subs and both are not working, one is a def tech pf15tl+ and the other is a jbl venue 12, both have amp issues, have recapped the jbl with no luck and also replaced the filter caps on the def tech also no luck. Tired of plate amps, thinking of just buying a external amp to get at least one of these working, not sure what I need to do this and how to hook up to what is there already. I have been reading and researching alot but am new to this and would really appreciate some advice. Thanks

Hello all.
Has anyone know of a schematic that uses DAF 91,DL94,DK92,Df91 or some of them for a guitar amp.
I have a Roberts CR portable mains powered radio that I would like to convert

Thamks

Hi all, newbie here, still learning the ropes, and would appreciate a bit of advice!

I have a nifty little Steljes ML50HD, just cracked it open to see if a quick deoxidising of the volume pot would sort out a different problem, but then also noticed the GND screw and an empty GND spot on the PCB.

I presume the ground screw is grounding through the metal chassis, it isn't connected to anything else. Then I wondered if anything is supposed to be connected to the PCB GND? It sits on it's own just behind the phono RCA inputs. The power (DC input) is way across in the corner. Pictures attached.

Thanks for any help!

Hi. I have been away so long that did’nt remember my sign in info. So created new.

But here is my question. I have Technics SU-V900 power transformers, filter capasitors and heatsinks. Transformers secondaries are about 46VAC, so that makes quite high voltage after rectified and filtered. Caps are 12 000uF/71V

Do you have suggestion, what could be quite simple power amp schema for these voltages. I have found something, but don’t know how they sound.

First DIY project will be a Subwoofer, but ive not been able to source a budget plate-amplifier for a reasonable price in the UK. I need it to run a Peerless SLS 830667 and ideally would get a Dayton Audio SA70 70W, but they are only available on import via amazon, and shipping and taxes don't justify the cost. Any ideas where i could get a budget plate-amp? doesn't need to be a Dayton..

OK, after :
- The ULTIMATE 300B
- The ULTIMATE OTL6080

Now :
- The ULTIMATE KT120

Note : ULTIMATE seems to somewhat be pretentious, but it doesn't mean "The BEST", only "The LAST" for me, instead... L'ultime tentative... 😉

Like the other ULTIMATEs, it will be built in the same Hammond aluminium box :



The protoype looks like this below :

[/URL][/IMG]

The first measurements and scope examinations proved to be correct sans plus 😕 :



But far from amazing if I compare to the results given by my U-OTL 6080 😱 :



For the moment, except a 10dB NFB, I did not tried any other correction. I wonder if my STS AH50B output transformers (used) have not suffered... 😕

Here are their specs (AH50B and AH53B are nearly identical) - it's in French, but the numbers are understandable, fortunately :





As you can see, they are not "average" models, but... 😕😕😕

I'd be interested to see similar oscillograms of such kind of single-ended amp from you Guys, so thanks to post pictures ! 😉😉😉

A+!

Hi,

my Hypex quad UCD180 amp is humming.😡

This unit was build a couple of years ago but the humming only recently became an issue or more apparent when i added a minidsp 2x4HD.
But the minidsp does not seem to be at fault as the humm exists when testing the amp on the bench/kitchen table.

The amp consist of 2 smps400 power supplies each driving both an UCD180HG Hxr and an UCD180AD (with a modified opamp).


With the amps on; the test speaker (TangBand W3-871s) makes a barely audible hiss (no problem).
Once an XLR-interlink is connected to the chassis the humming starts, touching the interlink in the chassis reduces the humm.
When using my XLR to RCA interlinks, touching the male pole of the RCA amplifies the (50 Hz?) humm extremely.

see video

The weird thing is that with the mindsp connected the humming is intermittent.
It sometimes builds up and can be removed by touching/hitting/shaking the minidsp 😕

I have to add that the amp is normally not connected to an earthed socket (1980 building code). Using an earth socket makes humm less but does not remove it.

So what did I do wrong making the amp?

I've had time to tinker for the first time in a long time. I have been working on an amplifier in the style of the linked patents, which has a linear error correcting amplifier working in tandem with a switching amplifier.

US Patent 4,523,152
US Patent 5,905,407

I implemented the IR2010 gate driver after the IRAUDAMP9 gate driver example and ran into some unexpected behavior. When the switching part of the amplifier (disconnected from everything else) has no logic power supply, but does have its main supply, its output was going high or periodically oscillating to high (brief blips at 50Hz or 120Hz intervals). After much debugging, the only thing that fixed it was to eliminate the bootstrap charging resistors which charge the high side floating power supply before the logic supply takes over via the bootstrap diode.

Is anyone familiar with this problem of self turn on in the absence of a logic supply? I can't tell from the datasheet whether the IR2010 outputs are specified to be high, low, or open in the absence of its logic power supply.

In my design I have a 10kOhm resistor to floating return on the output of the transistor buffer, but I omitted any resistor to return on the input to the buffer. I thought that might have been an oversight, and soldered in a resistor manually and still ran into problems with self turn on. This happened with that stage loaded or unloaded.

The switching part of the amplifier is now happily working without the bootstrap charging resistors, and the switching waveforms do not have excessive ringing on the oscilloscope. I'd like to try to fix this though, because now there is a 100uS long large voltage blip after turning on the amplifier due to the bootstrap being uncharged, which wasn't there earlier.

The gate driver circuit is attached, the resistor in question is RB57, which appears to causes unwanted turn on in the absence of the logic supply when the main supply is active.

Self-Assemble Speaker Kits – PBN Audio

they seems to be only simulated crossover on measured speakers, but i don't see the real and final measurement of cmplete system.

have someone of you experiences over these kits, are they reliable ?

thank you

I spent considerable time replying to a post over a few hours & when I pressed the submit it said it had timed out & to press the back button, re-load the page & re-send. BUT, all my work had disappeared. - Where did it go & how do I retrieve it ?

There isn't a parasound or repair dealer in my state 🙁

Here is what I have tried so far or diagnosed
-Shake it and smacked it, no effect
-checked and removed fuses and no luck, fuses are good
-I can hear a relay click over when it starts up
-The amp doesn't go into standby
-The right channel works and it will work as loud as my ears can handle my speakers
-The left channel will work at lower volumes but when a high pitch tone hits then static will appear. When I start to increase the volume the channel becomes nothing but static.

I have access to a digital multimeter and I think one of the transistors has went out but I need help on figuring out which multimeter went bad. I set the dmm to a continuity check and got resistances across across the legs.

here are some pictures of the amp, they are 1600x1200
http://webpages.charter.net/ajbertelson/diyaudio/top01.JPG
http://webpages.charter.net/ajbertelson/diyaudio/top02.JPG
http://webpages.charter.net/ajbertelson/diyaudio/transistors.JPG
http://webpages.charter.net/ajbertelson/diyaudio/centertransistors.JPG
http://webpages.charter.net/ajbertelson/diyaudio/transistorscloesup01.JPG
http://webpages.charter.net/ajbertelson/diyaudio/transistorscloesup02.JPG


This is my first time working with amps and I know I am playing with fire but I was wondering if I would be able to get some help in figuring out what went wrong. I am trying to learn about this stuff more.

This is a new thread specifically regarding my version of the Murphy Corner loaded line array using Vifa TC9 and stealing ideas from both RA7 and wesayso's line array threads.

Mine will be somewhat unique in that I can build them into the walls themselves so I can get the drivers as close to the corner as possible while also optimizing the enclosure volume.

Still in planning stages, but here's what I'm thinking so far.

- Power through 2 DIY NCore 400 monoblocks
- DSP through either miniDSP or whatever may come with the HT receiver I end up purchasing... perhaps an XMC from Emotiva.
- I have two Stereo Integrity 18' already with the intent of an IB subwoofer but may not use them if I can EQ the arrays to sufficiently represent HT bass.
- Will be building in surrounds into the ceilings (Atmos) and walls
- Room is about 11' wide by 20' deep. I'll throw up a sketch at some point.
- Sources will be a variety of things from SACD to vinyl to CD to HTPC.

And as no thread is complete without some pictures, here is where the remodel is at the moment:

The old room is gone and here we have some jack hammering to reinforce the foundation:


One interesting tidbit...



Our house was full of old knob and tube wiring. There are a few spots where it appears the wiring got super hot (short?) to the point of charring the nearby wood! Not sure how this was discovered as it also appears as if some tar or some other insulating substance was applied on the wires. In any case, we're rewiring the entire house so this won't be an issue again. While I'm on the topic though, is there anything I should specify for the HT room itself? I'm not a huge believer in power conditioning or whatever, but thought it would be worth asking.

Finally, in case you're curious... here's a shot of the second floor totally gutted:


This is through the kitchen into the two rear bedrooms which happen to be directly above the first shot.

Thanks in advance for all your help to come!

I hate starting new threads for a single question [EDIT: after posting this, I laugh at my thought of it really only being one question], but I can't seem to find info upon searching...


I plan to use the attached circuit (or a variation of it) in my new build. I'm starting this thread because it might help someone else that isn't interested in the amplifier.

Ignore the power supply (I'm going to tap off of the existing B+).

I want this meter to be "peaky", I assume C2 makes the meter more normalized/smooth? If so, removing it should work?

Is D1 there to make the signal DC? W1 wiper connects to the top of R2. If I changed the 100k pot to 1M, would I have to adjust the capacitors to compensate?

Why can't I just drive it like a normal triode? I will have a 1:20 gain stage to boost the level from line already... Can't I just put a biasing resistor on the cathode and feed it AC signal?

W2 on the cheap 8$ VU meter boards almost always smokes after 5 minutes in my experience (literal smoke). Replacing it with a 2W 500k part just showed you only really need a ~100k part for adjustability.

I want to build a push pull amp with the directly heated tetrode 2E25 operated in triode mode. My question is, should I connect the beam plates to the cathode?

I have a Musical Fidelity M1HPA and I see my woofers move slowly back and forth. If vol pot is turned down the movement is worst. Maybe 5 mm. When itøs turned all the way up, there is no cone movement.

What can be wrong?

Cleaning the garage... For sale 4 Dayton Audio DC180-8 absolutely NEW.
One of them measured and then installed in cabinets. I had no time to do a crossover and this projet is cancelled. Never used.

Selling in pairs:
1 pair: 40€
2 pairs: 70€

I could trade for... i don't know, but I don't want to put money.

Thank you